INKJET RECORDING APPARATUS

BACKGROUND OF THE INVENTION
Field of the Invention

The present invention relates to an inkjet recording apparatus that forms an image on a sheet.

Description of the Related Art

Hitherto, an inkjet type image forming apparatus that ejects ink onto a recording medium such as a sheet to print an image includes a recording head unit including an inkjet head that ejects the ink in an image forming portion. The inkjet head of the recording head unit is a precision part that requires precise control, and is disposed close to a recording side of the recording medium to execute image forming processing.

In such an inkjet type image forming apparatus, in a case where the inkjet head comes into contact with the recording medium where uplift has occurred, the inkjet head may be damaged. Therefore, the inkjet type image forming apparatus needs to remove the recording medium where the uplift has occurred without damaging the inkjet head and resume a job to perform error recovery.

Japanese Patent Application Laid-Open No. 2021-66129 discloses an inkjet recording apparatus that protects an inkjet head from a recording medium where uplift has occurred. The inkjet recording apparatus of Japanese Patent Application Laid-Open No. 2021-66129 immediately retracts an inkjet head portion from a conveyance path when the recording medium where the uplift has occurred is detected, thereby avoiding damage of the inkjet head due to contact between the recording medium where the uplift has occurred and the inkjet head. However, Japanese Patent Application Laid-Open No. 2021-66129 does not disclose how to perform error recovery by discharging the recording medium where the uplift has occurred after retracting the inkjet head.

On the other hand, Japanese Patent Application Laid-Open No. 2004-20650 discloses an error recovery method at the time of detection of an abnormal sheet. In a case where inspection processing is executed on a sheet after image formation and an abnormal sheet is detected, an image forming apparatus of Japanese Paten Application t Laid-Open No. 2004-20650 stores the detected abnormal sheet in a predetermined abnormal sheet storage portion and temporarily stores a normal sheet subsequent to the abnormal sheet in a predetermined normal sheet storage portion.

Further, when the storage of each sheet is completed, the image forming apparatus of Japanese Patent Application Laid-Open No. 2004-20650 starts feeding an additional sheet from a sheet tray, and forms an image scheduled to be printed on the abnormal sheet on the fed additional sheet. Then, when image forming processing on the additional sheet is completed, the image forming apparatus of Japanese Patent Application Laid-Open No. 2004-20650 starts feeding the normal sheet from the normal sheet storage portion again, and performs error recovery according to an order of sheet discharge.

However, in Japanese Patent Application Laid-Open No. 2004-20650, the error recovery is performed without considering a portion where an abnormality has occurred in the abnormal sheet, and thus there is a problem that the error recovery cannot be appropriately performed.

Specifically, in a case where an abnormality has occurred at a trailing edge portion of the abnormal sheet in a conveyance direction, reprinting on the normal sheet cannot be performed in time because processing of transferring the image scheduled to be printed on the abnormal sheet to the normal sheet cannot be performed in time. Furthermore, in a case where the uplift has occurred at a central portion of the abnormal sheet in the conveyance direction, the uplift can be suppressed by ejecting ink from an inkjet head, and thus, the inkjet head may need not be retracted. In this case, unnecessary inkjet head retraction control is performed.

SUMMARY OF THE INVENTION

It is desirable to provide an inkjet recording apparatus capable of appropriately performing recovery when a sheet is detected by performing the recovery according to a position of the detected sheet.

An inkjet recording apparatus according to the present invention includes: an accommodating portion configured to accommodate a sheet; a feeding portion configured to feed the sheet accommodated in the accommodating portion; a conveying portion configured to convey the sheet fed by the feeding portion; an ink head portion configured to eject ink onto the sheet conveyed by the conveying portion to form an image; a detector provided downstream of the feeding portion and upstream of the ink head portion in a conveyance direction of the sheet and configured to detect the sheet conveyed by the conveying portion; a first stack tray provided downstream of the ink head portion in the conveyance direction and on which the sheet conveyed by the conveying portion is stacked; a second stack tray provided downstream of the ink head portion in the conveyance direction and on which the sheet conveyed by the conveying portion is stacked; and a controller configured to control the conveying portion such that the sheet detected by the detector and a subsequent sheet fed by the feeding portion and following the sheet detected by the detector pass through the ink head portion without forming the image and are discharged to the first stack tray, and control the conveying portion such that a preceding sheet preceding the sheet detected by the detector is discharged to the second stack tray, in a case where a downstream side of the sheet with respect to a central position of a length of the sheet in the conveyance direction is detected by the detector.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are a schematic view and a diagram of an image forming apparatus according to a first embodiment of the present invention;

FIGS. 2A to 2C are schematic views illustrating an operation of a printing portion of the image forming apparatus according to the first embodiment of the present invention;

FIGS. 3A to 3D are a perspective view of an optical sensor of the image forming apparatus according to the first embodiment of the present invention and schematic views illustrating an operation of the printing portion;

FIG. 4 is a block diagram illustrating a hardware configuration of the image forming apparatus according to the first embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a configuration of a software module of the image forming apparatus according to the first embodiment of the present invention;

FIG. 6 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention immediately before detection of a misfed sheet during single-sided printing;

FIG. 7 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention after detection of the misfed sheet and before sheet discharge during the single-sided printing;

FIG. 8 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention in which all sheets are discharged to a sheet discharge destination in a case where an edge portion fold has occurred at a leading edge portion of the misfed sheet in a conveyance direction during the single-sided printing;

FIG. 9 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention in which all sheets are discharged to the sheet discharge destinations in a case where the edge portion fold has occurred at a trailing edge portion of the misfed sheet in the conveyance direction during the single-sided printing;

FIG. 10 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention immediately before detection of the misfed sheet whose both sides are blank during double-sided printing;

FIG. 11 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention after detection of the misfed sheet whose both sides are blank and before the sheet discharge during the double-sided printing;

FIG. 12 is a schematic view illustrating a state of the image forming apparatus according to the first embodiment of the present invention in which the misfed sheet whose both sides are blank is discharged to the sheet discharge destination during the double-sided printing;

FIG. 13 is a schematic view illustrating a state of the image forming apparatus according to the first embodiment of the present invention in which all sheets are discharged when the misfed sheet whose both sides are blank and where the edge portion fold has occurred at the leading edge portion in the conveyance direction is detected during the double-sided printing;

FIG. 14 is a schematic view illustrating a state of the image forming apparatus according to the first embodiment of the present invention in which all sheets are discharged when the misfed sheet whose both sides are blank and where the edge portion fold has occurred at the trailing edge portion in the conveyance direction is detected during the double-sided printing;

FIG. 15 is a schematic view of a state of the image forming apparatus according to the first embodiment of the present invention immediately before detection of the misfed sheet on which an image has been printed only on a front side during the double-sided printing;

FIG. 16 is a schematic view illustrating a state of the image forming apparatus according to the first embodiment of the present invention in which the misfed sheet on which the image has been printed only on the front side is discharged during the double-sided printing;

FIG. 17 is a schematic view illustrating a state of the image forming apparatus according to the first embodiment of the present invention in which all sheets are discharged when the misfed sheet on which the image has been printed only on the front side is detected during the double-sided printing;

FIG. 18 is a diagram illustrating an example of a sheet discharge destination management table used by the image forming apparatus according to the first embodiment of the present invention;

FIG. 19 is a sequence diagram illustrating an operation based on the software module of the image forming apparatus according to the first embodiment of the present invention;

FIG. 20 is a flowchart illustrating an operation of hardware of the image forming apparatus according to the first embodiment of the present invention;

FIG. 21 is a flowchart illustrating a procedure of misfed sheet detection control processing executed by the image forming apparatus according to the first embodiment of the present invention;

FIG. 22 is a flowchart illustrating a procedure of print head control processing executed by the image forming apparatus according to the first embodiment of the present invention;

FIG. 23 is a flowchart illustrating a procedure of print head retraction processing executed by the image forming apparatus according to the first embodiment of the present invention;

FIG. 24 is a flowchart illustrating a procedure of sheet conveyance control processing executed by the image forming apparatus according to the first embodiment of the present invention;

FIG. 25 is a flowchart illustrating a procedure of remaining sheet detection control processing executed by the image forming apparatus according to the first embodiment of the present invention;

FIG. 26 is a flowchart illustrating a procedure of conveyance rerouting control processing executed by the image forming apparatus according to the first embodiment of the present invention; and

FIG. 27 is a flowchart illustrating a procedure of conveyance rerouting control processing executed by an image forming apparatus according to a second embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference to the drawings.

First Embodiment
<Configuration of Image Forming Apparatus>

A configuration of an image forming apparatus 10 according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1A to 4.

FIG. 1A illustrates an entire configuration of the image forming apparatus 10, and FIG. 1B illustrates an internal configuration of the image forming apparatus 10.

FIG. 2A illustrates a relationship between a sheet whose leading edge portion in a conveyance direction is folded and an inkjet head 201 that has moved to a printing position. FIG. 2B illustrates a relationship between the sheet whose leading edge portion in the conveyance direction is folded and the inkjet head 201 that has moved to a retraction position. FIG. 2C illustrates a relationship between the sheet whose trailing edge portion in the conveyance direction is folded and the inkjet head 201 that has moved to the printing position. Here, printing means forming an image.

FIG. 3A illustrates a relationship between the sheet and the inkjet head 201 performing the printing at the printing position when it is detected that the trailing edge portion in the conveyance direction is folded. FIG. 3B illustrates a relationship between the sheet where uplift has occurred and the inkjet head 201 before the printing. FIG. 3C illustrates a relationship between the sheet where uplift has occurred and the inkjet head 201 performing the printing. FIG. 3D is a perspective view of an optical sensor 210.

Here, the image forming apparatus 10 as an inkjet recording apparatus is exemplified by a large commercial printer including a plurality of sheet discharge ports. A print server 70 is connected to the image forming apparatus 10. The image forming apparatus 10 starts a printing operation by receiving a print job transmitted from the print server 70. Here, the print server 70 can confirm a state of the image forming apparatus 10, monitor the print job, and perform maintenance control, and can execute various functions of the image forming apparatus 10 by comprehensively operating the image forming apparatus 10.

Specifically, the image forming apparatus 10 includes a sheet feeding portion 100, a printing portion 200, a fixing portion 300, a cooling portion 400, a reversing portion 500, a sheet discharge portion 600, a conveying portion 700, a controller unit 1000, and a printer engine 1009.

The sheet feeding portion 100 is a unit that holds a sheet and feeds the held sheet to the printing portion 200. The sheet feeding portion 100 includes a first stage sheet feeding portion 100a, a second stage sheet feeding portion 100b, and a third stage sheet feeding portion 100c. The sheet feeding portion 100 has a configuration in which three sheet feeding portions of the first stage sheet feeding portion 100a, the second stage sheet feeding portion 100b, and the third stage sheet feeding portion 100c having the same configuration are continuously connected.

The first stage sheet feeding portion 100a includes a sheet feeding cassette 110, a sheet feeding cassette 111, a sheet feeding cassette 112, a sheet discharge port 113, a sheet feeding portion 1TOP tray 114, a feeding portion 115, a feeding portion 116, and a feeding portion 117.

The sheet feeding cassette 110 as an accommodating portion is the uppermost sheet feeding cassette, and holds various printing sheets used for printing processing.

The sheet feeding cassette 111 as the accommodating portion is the middle sheet feeding cassette disposed between the sheet feeding cassette 110 and the sheet feeding cassette 112, and holds various printing sheets used for the printing processing.

The sheet feeding cassette 112 as the accommodating portion is the lowermost sheet feeding cassette, and holds various printing sheets used for the printing processing.

The sheet discharge port 113 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet feeding portion 1TOP tray 114.

The sheet discharge port 113 is provided at a distal end of a branch conveying portion branched from a branch position B3 of the conveying portion 700.

The sheet feeding portion 1TOP tray 114 is provided upstream of the optical sensor 210 described below of the printing portion 200 in the conveyance direction of the sheet (hereinafter, simply referred to as “conveyance direction”). The sheet discharged through the sheet discharge port 113 is stacked on the sheet feeding portion 1TOP tray 114.

The feeding portion 115 feeds the sheet accommodated in the sheet feeding cassette 110.

The feeding portion 116 feeds the sheet accommodated in the sheet feeding cassette 111.

The feeding portion 117 feeds the sheet accommodated in the sheet feeding cassette 112.

The second stage sheet feeding portion 100b includes a sheet feeding cassette 120, a sheet feeding cassette 121, a sheet feeding cassette 122, a sheet discharge port 123, a sheet feeding portion 2TOP tray 124, a feeding portion 125, a feeding portion 126, and a feeding portion 127.

The sheet feeding cassette 120 as the accommodating portion is the uppermost sheet feeding cassette, and holds various printing sheets used for the printing processing.

The sheet feeding cassette 121 as the accommodating portion is the middle sheet feeding cassette disposed between the sheet feeding cassette 120 and the sheet feeding cassette 122, and holds various printing sheets used for the printing processing.

The sheet feeding cassette 122 as the accommodating portion is the lowermost sheet feeding cassette, and holds various printing sheets used for the printing processing.

The sheet discharge port 123 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet feeding portion 2TOP tray 124. The sheet discharge port 123 is provided at a distal end of a branch conveying portion branched from a branch position B2 of the conveying portion 700.

The sheet feeding portion 2TOP tray 124 is provided upstream of the optical sensor 210 of the printing portion 200 in the conveyance direction. The sheet discharged through the sheet discharge port 123 is stacked on the sheet feeding portion 2TOP tray 124.

The feeding portion 125 feeds the sheet accommodated in the sheet feeding cassette 120.

The feeding portion 126 feeds the sheet accommodated in the sheet feeding cassette 121.

The feeding portion 127 feeds the sheet accommodated in the sheet feeding cassette 122.

The third stage sheet feeding portion 100c includes a sheet feeding cassette 130, a sheet feeding cassette 131, a sheet feeding cassette 132, a sheet discharge port 133, a sheet feeding portion 3TOP tray 134, a feeding portion 135, a feeding portion 136, and a feeding portion 137.

The sheet feeding cassette 130 as the accommodating portion is the uppermost sheet feeding cassette, and holds various printing sheets used for the printing processing.

The sheet feeding cassette 131 as the accommodating portion is the middle sheet feeding cassette disposed between the sheet feeding cassette 130 and the sheet feeding cassette 132, and holds various printing sheets used for the printing processing.

The sheet feeding cassette 132 as the accommodating portion is the lowermost sheet feeding cassette, and holds various printing sheets used for the printing processing.

The sheet discharge port 133 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet feeding portion 3TOP tray 134. The sheet discharge port 133 is provided at a distal end of a branch conveying portion branched from a branch position B1 of the conveying portion 700.

The sheet feeding portion 3TOP tray 134 is provided upstream of the optical sensor 210 of the printing portion 200 in the conveyance direction. The sheet discharged through the sheet discharge port 133 is stacked on the sheet feeding portion 3TOP tray 134.

The feeding portion 135 feeds the sheet accommodated in the sheet feeding cassette 130.

The feeding portion 136 feeds the sheet accommodated in the sheet feeding cassette 131.

The feeding portion 137 feeds the sheet accommodated in the sheet feeding cassette 132.

The printing portion 200 is a unit that performs an image forming operation of printing the image only on a front side of the sheet conveyed by the conveying portion 700 or on both of the front side and a back side. In single-sided printing in which the image is printed only on the front side, the printing portion 200 prints the image on the front side of the sheet which is fed from the sheet feeding portion 100 and of which the front side and the back side are both blank. In double-sided printing in which the image is printed on both of the front side and the back side, the printing portion 200 prints the image on the front side of the sheet which is fed from the sheet feeding portion 100 and of which both sides are blank. In the double-sided printing, the printing portion 200 prints the image on the back side of the sheet which is conveyed by the conveying portion 700 from the sheet feeding portion 100 and on which the image has been printed only on the front side.

The printing portion 200 includes the inkjet head 201 and the optical sensor 210.

The inkjet head 201 as an ink head portion is movable between the printing position illustrated in FIG. 2A and the retraction position illustrated in FIG. 2B under the control of a head controller 1010. Here, the printing position is a position where the image is printed by approaching the sheet conveyed by the conveying portion 700 and ejecting ink. The retraction position is a position separated from the sheet conveyed by the conveying portion 700, and is a position farther from the sheet than the printing position. The inkjet head 201 moves to the retraction position to avoid contact with a misfed sheet.

Here, the misfed sheet is an abnormal sheet in which an abnormality such as a fold of an edge portion (hereinafter, referred to as “edge portion fold”) in the conveyance direction of the sheet (hereinafter, simply referred to as “conveyance direction”) or uplift has occurred. In addition, a position where the abnormality has occurred in the misfed sheet in which the edge portion fold has occurred is a leading edge portion that is upstream of a central position of a length of the misfed sheet in the conveyance direction (hereinafter, referred to as “leading edge portion in the conveyance direction”) or a trailing edge portion that is downstream of the central position of the length of the misfed sheet in the conveyance direction (hereinafter, referred to as “trailing edge portion in the conveyance direction”), and a position where the abnormality has occurred in the misfed sheet in which the uplift has occurred is between the leading edge portion and the trailing edge portion in the conveyance direction.

The inkjet head 201 includes a plurality of recording heads 2011, 2012, 2013, and 2014.

The recording head 2011, the recording head 2012, the recording head 2013, and the recording head 2014 are line type recording heads using an inkjet method and arranged in the conveyance direction. A method using a heat generating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted as the inkjet method. Ink of each color is supplied from an ink reservoir to each of the recording head 2011, the recording head 2012, the recording head 2013, and the recording head 2014 via an ink tube.

The recording head 2011, the recording head 2012, the recording head 2013, and the recording head 2014 are recording heads of four colors of Bk (black), Y (yellow), M (magenta), and C (cyan), respectively. The number of colors and the number of recording heads of the inkjet head 201 are not limited to four colors and four and may be any number of colors and any number. For example, the number of colors may be one, and the number of recording heads may be one.

The optical sensor 210 as a detector detects the abnormality such as the edge portion fold or uplift of the sheet conveyed by the conveying portion 700, and outputs an electric signal corresponding to a detection result to the controller unit 1000. The optical sensor 210 is provided upstream of the inkjet head 201 in the conveyance direction, and detects the misfed sheet before the image is printed by the inkjet head 201.

Specifically, the optical sensor 210 includes a light projecting portion 2101 and a light receiving portion 2102.

The light projecting portion 2101 emits a laser toward the light receiving portion 2102.

The light receiving portion 2102 includes a light receiving element (CCD). The light receiving portion 2102 enters a light receiving state in which the laser emitted from the light projecting portion 2101 is received by the light receiving element or a light blocked state in which the laser cannot be received by the light receiving element because the laser is blocked by a blocking object interposed between the light receiving element and the light projecting portion 2101. The blocking object is the edge portion fold of the misfed sheet, the uplift of the misfed sheet, or the like.

In a case where the light receiving element of the light receiving portion 2102 is in the light blocked state because there is a blocking object between the light projecting portion 2101 and the light receiving portion 2102, a bright portion (light incident portion) that receives the laser from the light projecting portion 2101 and a dark portion (light blocked portion) that corresponds to a shadow of the blocking object are generated. The light receiving portion 2102 outputs an electric signal corresponding to a light receiving quantity of the laser in the light receiving state or the light blocked state of the light receiving element to the controller unit 1000 via the printer engine 1009.

The fixing portion 300 is a unit that performs fixing control of fixing the image printed on the sheet to the sheet by using a plurality of heater units for the sheet which is conveyed by the conveying portion 700 and on which the image has been printed in the printing portion 200. The fixing portion 300 includes a sheet discharge port 301.

The sheet discharge port 301 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to a fixing portion double-sided tray. The sheet discharge port 301 is provided at a distal end of a branch conveying portion branched from a branch position B4 of the conveying portion 700.

The cooling portion 400 is a unit that performs temperature control of cooling the sheet which is conveyed by the conveying portion 700 and on which the image is fixed in the fixing portion 300 to normal temperature by using a plurality of fan units.

The reversing portion 500 performs switchback conveyance of the sheet cooled in the cooling portion 400 and conveyed by the conveying portion 700. The reversing portion 500 reverses the front side and the back side of the sheet such that the back side of the sheet printed on both of the front side and the back side is changed from an upper side to a lower side by performing switchback conveyance of the sheet. The reversing portion 500 includes a sheet discharge port 501 and a reversing portion TOP tray 502.

The sheet discharge port 501 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the reversing portion TOP tray 502. The sheet discharge port 501 is provided at a distal end of a branch conveying portion branched from a branch position B5 of the conveying portion 700.

The sheet discharged from the sheet discharge port 501 is stacked on the reversing portion TOP tray 502 as a first stack tray.

The sheet discharge portion 600 is a unit that performs control to stack and discharge the sheet conveyed by the conveying portion 700 from the reversing portion 500. The sheet discharge portion 600 has a configuration in which three units of the same sheet discharge portions of a first stage sheet discharge portion 600a, a second stage sheet discharge portion 600b, and a third stage sheet discharge portion 600c are continuously connected.

The first stage sheet discharge portion 600a includes a discharged sheet stacker 611, a sheet discharge port 612, and a sheet discharge portion 1TOP tray 613.

The sheet on which the image has been printed on both sides and which is discharged by the conveying portion 700 is stacked on the discharged sheet stacker 611 as a second stack tray.

The sheet discharge port 612 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet discharge portion 1TOP tray 613. The sheet discharge port 612 is provided at a distal end of a branch conveying portion branched from a branch position B6 of the conveying portion 700.

The sheet discharged through the sheet discharge port 612 is stacked on the sheet discharge portion 1TOP tray 613 as the first stack tray.

The second stage sheet discharge portion 600b includes a discharged sheet stacker 621, a sheet discharge port 622, and a sheet discharge portion 2TOP tray 623.

The sheet on which the image has been printed on both sides and which is discharged by the conveying portion 700 is stacked on the discharged sheet stacker 621 as the second stack tray.

The sheet discharge port 622 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet discharge portion 2TOP tray 623. The sheet discharge port 622 is provided at a distal end of a branch conveying portion branched from a branch position B7 of the conveying portion 700.

The sheet discharged through the sheet discharge port 622 is stacked on the sheet discharge portion 2TOP tray 623 as the first stack tray.

The third stage sheet discharge portion 600c includes a discharged sheet stacker 631, a sheet discharge port 632, and a sheet discharge portion 3TOP tray 633.

The sheet on which the image has been printed on both sides and which is discharged by the conveying portion 700 is stacked on the discharged sheet stacker 631 as the second stack tray.

The sheet discharge port 632 is provided to discharge and retract the sheet conveyed by the conveying portion 700 to the sheet discharge portion 3TOP tray 633. The sheet discharge port 632 is provided at a distal end of a branch conveying portion branched from a branch position B8 of the conveying portion 700.

The sheet discharged through the sheet discharge port 632 is stacked on the sheet discharge portion 3TOP tray 633 as the first stack tray.

During the single-sided printing, the conveying portion 700 conveys the sheet fed from the sheet feeding portion 100 in the order of the printing portion 200, the fixing portion 300, the cooling portion 400, the reversing portion 500, and the sheet discharge portion 600. During the double-sided printing, the conveying portion 700 conveys the sheet fed from the sheet feeding portion 100 in the order of the printing portion 200, the fixing portion 300, and the cooling portion 400. Thereafter, the conveying portion 700 conveys the sheet in the order of the cooling portion 400, the fixing portion 300, the printing portion 200, the sheet feeding portion 100, the printing portion 200, the fixing portion 300, the cooling portion 400, the reversing portion 500, and the sheet discharge portion 600.

The conveying portion 700 performs sheet discharge to the sheet feeding portion 1TOP tray 114, the sheet feeding portion 2TOP tray 124, the sheet feeding portion 3TOP tray 134, or the fixing portion double-sided tray through the sheet discharge port 113, 123, 133, or 301. Alternatively, the conveying portion 700 performs sheet discharge to the reversing portion TOP tray 502, the sheet discharge portion 1TOP tray 613, the sheet discharge portion 2TOP tray 623, or the sheet discharge portion 3TOP tray 633 through the sheet discharge port 501, 612, 622, or 623.

The controller unit 1000 is connected to an external device via the printer engine 1009 and a local area network 1007. The controller unit 1000 comprehensively controls an operation of the image forming apparatus 10, and performs input/output control of device information and a sensor signal with the printer engine 1009 and an external device.

The controller unit 1000 is not limited to be configured as one unit, and may be provided in each of the sheet feeding portion 100, the printing portion 200, the fixing portion 300, the cooling portion 400, the reversing portion 500, and the sheet discharge portion 600. In a case where the controller unit 1000 is provided in each of the sheet feeding portion 100, the printing portion 200, the fixing portion 300, the cooling portion 400, the reversing portion 500, and the sheet discharge portion 600, a specific controller unit 1000 comprehensively controls the other controller units 1000.

The controller unit 1000 includes a central processing unit (CPU) 1001, a random access memory (RAM) 1002, a read only memory (ROM) 1003, a hard disk drive (HDD) 1004, a network interface (I/F) 1006, a device I/F 1008, a head controller 1010, and a conveyance controller 1011.

The CPU 1001 reads a program stored in the ROM 1003 or the HDD 1004, stores the program in the RAM 1002, and executes the program stored in the RAM 1002 to control the operation of the image forming apparatus 10.

The CPU 1001 executes the program stored in the RAM 1002 to comprehensively control each device connected via a system bus 1005. When the image forming apparatus 10 is powered on, the CPU 1001 performs predetermined control by reading and executing the program stored in the ROM 1003. The CPU 1001 installs the program received by the network I/F 1006 in the ROM 1003 or the HDD 1004. The CPU 1001 transmits data or device information generated in the control of the operation of the image forming apparatus 10 to an external device via the network I/F 1006 and the local area network 1007.

The CPU 1001 acquires image data transferred from the print server 70 via the local area network 1007 and the network I/F 1006. The CPU 1001 drives each device of the printer engine 1009 via the device I/F 1008 based on the acquired image data to print the image on the sheet.

The CPU 1001 controls the head controller 1010 and the conveyance controller 1011 based on an electric signal input from the optical sensor 210 via the printer engine 1009 and the device I/F 1008.

Specifically, the CPU 1001 executes misfed sheet detection control processing described below to detect the misfed sheet based on an electric signal corresponding to the light receiving state or the light blocked state in the light receiving element of the light receiving portion 2102 input from the optical sensor 210. For example, the CPU 1001 determines a portion where the light receiving quantity of the light receiving portion 2102 indicated by the electric signal input from the light receiving portion 2102 is less than a reference as the light blocked portion, and detects the misfed sheet that is the blocking object in a case where the light blocked portion occupies a predetermined ratio or more.

When the misfed sheet is detected, the CPU 1001 determines a position where the edge portion fold or uplift of the misfed sheet has occurred. For example, the CPU 1001 determines the position where the edge portion fold or uplift of the misfed sheet has occurred by using a time required for the sheet to pass through the optical sensor 210 once or twice at a predetermined sheet conveyance speed from a sheet feeding start time, and sheet information such as a size of the sheet. The sheet information is, for example, information included in an electric signal that is input to an operation portion by a user operation and is input to the CPU 1001 from the operation portion according to a user operation.

When the misfed sheet is detected, the CPU 1001 executes print head control processing and sheet conveyance control processing described below based on the determined position where the edge portion fold or uplift of the misfed sheet has occurred. The CPU 1001 executes the print head control processing to control the head controller 1010 to move the inkjet head 201 from the printing position to the retraction position or from the retraction position to the printing position. The CPU 1001 executes the sheet conveyance control processing to control the conveyance controller 1011 to discharge the sheet (hereinafter, referred to as “preceding sheet”) conveyed before the abnormal sheet to a normal sheet discharge destination and discharge and temporarily retract the sheet (hereinafter, referred to as “subsequent sheet”) conveyed after the abnormal sheet to a predetermined sheet discharge destination.

When the misfed sheet is detected, the CPU 1001 executes remaining sheet detection processing described below to discharge the misfed sheet and the subsequent sheet, and then check whether or not there is a sheet remaining on a conveyance path.

The CPU 1001 executes image transfer processing (bitmap shift) as recovery processing for printing, on the subsequent sheet, the image scheduled to be printed on the misfed sheet or the image being printed on the misfed sheet by the inkjet head 201.

The CPU 1001 is not limited to be provided in the controller unit 1000, and may be provided in a controller unit present in each of the sheet feeding portion 100, the printing portion 200, the fixing portion 300, the cooling portion 400, the reversing portion 500, and the sheet discharge portion 600.

The RAM 1002 functions as a main memory or a work memory of the CPU 1001. The RAM 1002 stores the program read from the ROM 1003 or the HDD 1004 by the CPU 1001.

The ROM 1003 stores various programs such as a control program and a boot program, and various tables including a sheet discharge destination management table described below.

The HDD 1004 stores various programs including an operating system (OS) program. The HDD 1004 is also used for the purpose of temporarily or long-term holding a large amount of data. The program stored in the HDD 1004 is described below.

The network I/F 1006 is an interface unit with the local area network 1007, and is connected to the local area network 1007. The network I/F 1006 receives data, device information, or a program from an external device via the local area network 1007, and outputs the received data, device information, or program to the CPU 1001. The network I/F 1006 transmits data or device information output from the CPU 1001 to an external device via the local area network 1007.

The device I/F 1008 is an interface unit with the printer engine 1009, and is connected to the printer engine 1009. The device I/F 1008 inputs and outputs signals for operating and referring to various motors, sensors, the inkjet head 201, and the like between the CPU 1001 and the printer engine 1009.

The head controller 1010 controls an operation of the inkjet head 201 included in the printer engine 1009 via the device I/F 1008 under the control of the CPU 1001.

The conveyance controller 1011 controls an operation of feeding the sheet from the sheet feeding portion 100 under the control of the CPU 1001. The conveyance controller 1011 controls an operation of a conveyance motor under the control of the CPU 1001 in order to convey the sheet by the conveying portion 700 and discharge the sheet to the sheet discharge portion 600 in synchronization with an ink discharge timing of the inkjet head 201. The conveyance controller 1011 controls sensors including the optical sensor 210 under the control of the CPU 1001. The conveyance controller 1011 controls the operation of the conveyance motor under the control of the CPU 1001 to discharge and temporarily retract the sheet being conveyed to the predetermined sheet discharge destination when the misfed sheet is detected.

The printer engine 1009 includes the inkjet head 201 and the like. The optical sensor 210, various motors, and the like are connected to the printer engine 1009. The printer engine 1009 is an inkjet type output device that conveys the sheet under the control of the controller unit 1000 and prints the image on the sheet by the inkjet head 201.

A configuration of a software module included in the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail with reference to FIG. 5.

The image forming apparatus 10 includes the software module including a comprehensive device controller 1, a head operation controller 2, a misfed sheet detector 3, a job manager 4, and a conveyance operation controller 5. The software module is stored in the HDD 1004 as a program.

The comprehensive device controller 1 comprehensively controls execution of the sheet conveyance control processing, control processing for the sensors including the optical sensor 210, the print head control processing, job control processing, and the like.

The head operation controller 2 controls an operation related to the inkjet head 201. The operation related to the inkjet head 201 includes an operation of ejecting the ink onto the sheet, an operation of moving the inkjet head 201 to the retraction position when the misfed sheet is detected, an operation of moving the inkjet head 201 to the printing position after error recovery processing, and the like. Here, the error recovery processing is processing of retracting the print job being executed when the misfed sheet is detected and discharging the misfed sheet and the subsequent sheet to the predetermined sheet discharge destination to prepare for the retracted print job to be re-input.

The misfed sheet detector 3 controls the optical sensor 210 to monitor a state of the sheet conveyed during the print job, and immediately notifies the comprehensive device controller 1 of detection of the misfed sheet.

The job manager 4 performs scheduling for the print job and temporary retraction control for print job data at the time of the error recovery processing. The job manager 4 performs re-generation control for the print job data for arranging a page order of the sheets and re-scheduling after the error recovery processing.

The conveyance operation controller 5 controls conveyance of the sheet for the print job, discharge of the misfed sheet to the sheet discharge destination, retraction of the sheet being conveyed to the sheet discharge destination when the misfed sheet is detected, and re-conveyance of the sheet for a recovery job.

The operation of the inkjet head 201 of the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2A to 3C.

As illustrated in FIG. 2A, in a case where the edge portion fold has occurred at the leading edge portion of the sheet in the conveyance direction, when the misfed sheet is detected by the optical sensor 210, the inkjet head 201 is moved from the printing position to the retraction position. As a result, a collision between the inkjet head 201 and the misfed sheet can be avoided as illustrated in FIG. 2B.

On the other hand, in a case where the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction as illustrated in FIG. 2C, in many cases, printing of the image on the leading edge portion of the misfed sheet in the conveyance direction has already started before the abnormality is detected particularly in the case of a large-sized sheet. In this case, the abnormality is detected when the image is printed in a trailing edge region in the conveyance direction as illustrated in FIG. 3A, the trailing edge region being a final region in an image printing region of the misfed sheet.

In this case, when continuing printing of the image on the subsequent sheet, the inkjet head 201 is immediately retracted from the printing position to the retraction position when the misfed sheet is detected. Then, it is necessary to move the inkjet head 201 from the retraction position to the printing position before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches. In addition, it is necessary to perform nozzle control for the inkjet head 201 to bring the inkjet head into a printable state and perform transfer of a bitmap image scheduled to be printed on the misfed sheet before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches.

However, in many cases, the movement of the inkjet head 201, the nozzle control, and the transfer of the bitmap image are not performed in time before the leading edge of the normal sheet following the misfed sheet in the conveyance direction reaches in a case where the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction. Therefore, in a case where the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction, the image forming apparatus 10 temporarily discharges and retracts the subsequent sheet whose both sides are blank or all the subsequent sheets according to a printing state of the misfed sheet.

Further, in a case where slight uplift has occurred between the leading edge portion and the trailing edge portion of the sheet in the conveyance direction as illustrated in FIG. 3B, the uplift of the sheet is suppressed by the ink ejected from the inkjet head 201. In this case, as illustrated in FIG. 3C, the collision between the inkjet head 201 and the sheet can be avoided. Therefore, it is possible to regard the misfed sheet where the slight uplift has occurred between the leading edge portion and the trailing edge portion in the conveyance direction of the sheet as the normal sheet, and to continue printing the image on the misfed sheet.

Therefore, the image forming apparatus 10 conveys the misfed sheet where the slight uplift has occurred between the leading edge portion and the trailing edge portion in the conveyance direction as it is without retracting, and continues an operation of printing the image on the misfed sheet where the slight uplift has occurred between the leading edge portion and the trailing edge portion in the conveyance direction.

A conveyance operation of the image forming apparatus 10 during a single-sided job according to the first embodiment of the present invention will be described in detail. Here, the single-sided job is a print job of printing the image only on the front side of the sheet.

The image forming apparatus 10 discharges the misfed sheet to the predetermined sheet discharge destination when the misfed sheet where the edge portion fold has occurred at the leading edge portion or the trailing edge portion in the conveyance direction is detected. In addition, the image forming apparatus 10 continues printing of the image as it is in a case where the processing of transferring the image scheduled to be printed on the misfed sheet ends before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches. Here, a case where the processing of transferring the image scheduled to be printed on the misfed sheet ends before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches is a case where the edge portion fold has occurred at the leading edge portion of the sheet in the conveyance direction.

On the other hand, the image forming apparatus 10 discharges and retracts the normal sheet to the sheet discharge destination different from the sheet discharge destination of the misfed sheet in a case where the processing of transferring the image scheduled to be printed on the misfed sheet does not end before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches. Here, a case where the processing of transferring the image scheduled to be printed on the misfed sheet does not end before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches is a case where the edge portion fold has occurred at the trailing edge portion of the sheet in the conveyance direction.

Next, the conveyance operation during the single-sided job will be described in more detail with reference to FIGS. 6 to 9.

FIGS. 6 to 9 illustrate, as an example, a state in which 20 sheets from St1 to St20 are conveyed into the image forming apparatus 10.

Here, in FIG. 6, St1 has reached the discharged sheet stacker 611, and St16 is the misfed sheet and is at a position immediately before being detected as the misfed sheet by the optical sensor 210. Further, St1 to St15 which are the preceding sheets and St17 to St20 which are the subsequent sheets are the normal sheets where the edge portion fold or uplift has not occurred.

In a case where the edge portion fold has occurred at the leading edge portion of St16 in the conveyance direction, the image forming apparatus 10 immediately retracts the inkjet head 201 from the printing position to the retraction position, continues conveyance of St16, and waits for St16 to pass through the printing portion 200.

After St16 passes through the inkjet head 201, the image forming apparatus 10 moves the inkjet head 201 from the retraction position to the printing position, and resumes the printing of the image on St17 to St20. In addition, the image forming apparatus 10 executes processing of transferring the image scheduled to be printed on St16. By such processing of transferring the image, the image scheduled to be printed on St17 to St20 is shifted backward by one page. Therefore, St21 is additionally fed from the sheet feeding portion 100 to the printing portion 200 as illustrated in FIG. 7.

Then, as illustrated in FIG. 8, the image forming apparatus 10 discharges St16 through the sheet discharge port 501, and discharges St17 to St21 to the discharged sheet stacker 611, thereby discharging St1 to St15 and St17 to St21 to the discharged sheet stacker 611. Accordingly, the image forming apparatus 10 ends the print job.

On the other hand, in a case where the edge portion fold has occurred at the trailing edge portion of St16 in the conveyance direction, the image forming apparatus 10 cannot perform the processing of transferring the image scheduled to be printed on St17 in time before the leading edge portion of St16 in the conveyance direction reaches the inkjet head 201. In this case, the image forming apparatus 10 detects the misfed sheet at a timing when the processing of transferring the image has not ended before the inkjet head 201 starts printing the image on the subsequent sheet. Therefore, in this case, as illustrated in FIG. 9, the image forming apparatus 10 discharges St16 through the sheet discharge port 501, and discharges and retracts St17 to St20, which are the subsequent sheets, through the sheet discharge port 113.

In FIG. 7, only St21 for one page is additionally fed, but the present invention is not limited thereto, and in a case where there are more subsequent pages, printing of the image may be continued until the last page.

Here, in a case where the edge portion fold has occurred at the trailing edge portion of St16 in the conveyance direction, conveyance may be controlled such that St17 to St20, which are the subsequent sheets, pass through the inkjet head 201 without performing printing of the image by the inkjet head 201 and are discharged to the sheet discharge portion 1TOP tray 613, the sheet discharge portion 2TOP tray 623, or the sheet discharge portion 3TOP tray 633, instead of the above-described conveyance operation.

A conveyance operation of the image forming apparatus 10 during a double-sided job according to the first embodiment of the present invention will be described in detail. Here, the double-sided job is a print job of printing the image on both of the front side and the back side of the sheet.

The image forming apparatus 10 switches the error recovery processing according to a position where the edge portion fold has occurred on the misfed sheet and the printing state of the misfed sheet.

Specifically, in a case where the image forming apparatus 10 detects the misfed sheet in the printing state in which both of the front side and the back side are blank, the misfed sheet is discharged to the predetermined sheet discharge destination. In addition, the image forming apparatus 10 continues printing of the image on the subsequent sheet as it is in a case where the processing of transferring the image scheduled to be printed on the misfed sheet ends before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches the inkjet head 201. On the other hand, the image forming apparatus 10 discharges and retracts the subsequent sheet whose both sides are blank to the sheet discharge destination different from the sheet discharge destination of the misfed sheet in a case where the transfer processing does not end before the leading edge portion of the normal sheet conveyed next to the misfed sheet in the conveyance direction reaches the inkjet head 201.

In addition, in a case where the image forming apparatus 10 detects the misfed sheet in the printing state in which the image has been printed only on the front side, the misfed sheet is discharged to the predetermined sheet discharge destination. Then, the image forming apparatus 10 discharges and retracts the subsequent sheet to the sheet discharge destination different from the sheet discharge destination of the misfed sheet regardless of the position where the edge portion fold has occurred on the misfed sheet in the conveyance direction.

Here, in a case where processing of transferring, to the subsequent sheet, the image scheduled to be printed on the back side of the misfed sheet on which the image has been printed only on the front side or the image being printed and continuing printing of the image is executed, the page order of the subsequent sheets is shifted. In order to prevent such a shift in the page order of the subsequent sheets, control of complicated conveyance timings and control of arranging the page order are required. Therefore, by discharging and retracting the subsequent sheet without continuing printing of the image on the subsequent sheet, it is possible to avoid the control of the complicated conveyance timings and the control of arranging the page order.

In the above description, the subsequent sheet following the misfed sheet on which the image has been printed only on the front side is discharged and retracted. However, the present invention is not limited thereto, and printing of the image on the subsequent sheet following the misfed sheet on which the image has been printed only on the front side may be continued by performing the control of the complicated conveyance timings and the control of arranging the page order.

Next, the conveyance operation of the image forming apparatus 10 during the double-sided job in a case where both the front side and the back side of St29, which is the misfed sheet, are blank will be described in more detail with reference to FIGS. 10 to 14.

FIGS. 10 to 14 illustrate, as an example, a state in which 33 sheets from St1 to St33 are conveyed into the image forming apparatus 10.

Here, in FIG. 10, St1 has reached the discharged sheet stacker 631, and St1 to St14, which are the preceding sheets, are the normal sheets on which the image has been printed on both the front side and the back side and no edge portion fold or uplift has occurred. In addition, St29 is the misfed sheet and is at a position immediately before being detected as the misfed sheet by the optical sensor 210. Further, St15 to St28, which are the preceding sheets, are the normal sheets on which the image has been printed only on the front side, and St30 to St33, which are the subsequent sheets, are the normal sheets whose both sides are blank.

In a case where St29 is detected as the misfed sheet, the image forming apparatus 10 immediately retracts the inkjet head 201 from the printing position to the retraction position, continues conveyance of St29, and waits for St29 to pass through the printing portion 200 as illustrated in FIG. 11.

In a case where the edge portion fold has occurred at the leading edge portion of St29 in the conveyance direction, after St29 passes through the printing portion 200, the image forming apparatus 10 returns the inkjet head 201 from the retraction position to the printing position, and discharges St29 through the sheet discharge port 501 as illustrated in FIG. 12.

In addition, the image forming apparatus 10 executes processing of transferring the image scheduled to be printed on St29 to the subsequent sheet, and continues conveyance of St15 to St28 on which the image has been printed only on the front side and St30 to St33 whose both sides are blank. In addition, since the page order is shifted by one page due to the transfer processing, the image forming apparatus 10 additionally feeds St34. Further, when the misfed sheet is detected, the image forming apparatus 10 discharges St1 to St14 on which the image has been printed on both of the front side and the back side to the discharged sheet stacker 631 which is the normal sheet discharge destination as they are.

As a result, as illustrated in FIG. 13, only St29, which is the misfed sheet, is discharged through the sheet discharge port 501, and St1 to St28 and St30 to St34, which are the normal sheets, are discharged to the discharged sheet stacker 631 which is the normal sheet discharge destination.

On the other hand, in a case where the edge portion fold has occurred at the trailing edge portion of St29 in the conveyance direction, the image forming apparatus 10 causes the inkjet head 201 to remain retracted to the retraction position and discharges St29 through the sheet discharge port 501. In addition, the image forming apparatus 10 does not execute the transfer processing since the processing of transferring the image being printed on St29 to the subsequent sheet cannot be executed in time.

In addition, when the misfed sheet is detected, the image forming apparatus 10 discharges St1 to St14 on which the image has been printed on both of the front side and the back side to the discharged sheet stacker 631 which is the normal sheet discharge destination they are. Further, the image forming apparatus 10 discharges St30 to St33 whose both sides are blank through the sheet discharge port 133 to the sheet discharge destination corresponding to a position when the misfed sheet is detected, and discharges and retracts St30 to St33 to the sheet discharge destination different from the sheet discharge destination of St29.

As a result, as illustrated in FIG. 14, St29 is discharged through the sheet discharge port 501, St1 to St28 are discharged to the discharged sheet stacker 631 which is the normal sheet discharge destination, and St30 to St33 are discharged through the sheet discharge port 113.

Next, a conveyance operation of the image forming apparatus 10 during the double-sided job in a case where the image has been printed only on the front side of St14, which is the misfed sheet, will be described in more detail with reference to FIGS. 15 to 17.

FIGS. 15 to 17 illustrate, as an example, a state in which 33 sheets from St1 to St33 are conveyed into the image forming apparatus 10.

Here, in FIG. 15, St1 has reached the discharged sheet stacker 631, and St1 to St13, which are the preceding sheets, are the normal sheets on which the image has been printed on both of the front side and the back side and no edge portion fold or uplift has occurred. In addition, St14 is the misfed sheet on which the image has been printed only on the front side, and is at a position immediately before being detected as the misfed sheet by the optical sensor 210. Further, St15 to St29, which are the subsequent sheets, are the normal sheets on which the image has been printed only on the front side, and St30 to St33, which are the subsequent sheets, are the normal sheets whose both sides are blank.

In a case where St14 is detected as the misfed sheet, the image forming apparatus 10 immediately retracts the inkjet head 201 from the printing position to the retraction position as illustrated in FIG. 16. At this time, the image forming apparatus 10 does not execute the transfer processing for transferring the image scheduled to be printed on St14 or the image being printed to the subsequent sheet.

The image forming apparatus 10 discharges St14, which is the misfed sheet, through the sheet discharge port 501. In addition, the image forming apparatus 10 is desired to be able to reuse St15 to St29 on which the image has been printed only on the front side and which are the subsequent sheets by the error recovery processing. Therefore, the image forming apparatus 10 discharges St15 to St29 through the sheet discharge port 113, discharges and retracts St15 to St29 to the sheet discharge destination different from the sheet discharge destination of St14. At this time, the image forming apparatus 10 discharges St15 to St29 to the downstream sheet discharge destination closest to St15 in the conveyance direction when the misfed sheet is detected.

In addition, the image forming apparatus 10 discharges the St30 to St33, which are the subsequent sheets and of which the both sides are blank, through the sheet discharge port 612 to the sheet discharge destination corresponding to a position when the misfed sheet is detected, and discharges and retracts St30 to St33 to the sheet discharge destination different from the sheet discharge destination of St14 to St29. Further, when the misfed sheet is detected, the image forming apparatus 10 discharges St1 to St13 on which the image has been printed on both of the front side and the back side to the discharged sheet stacker 631 which is the normal sheet discharge destination they are.

As a result, St14, which is the misfed sheet, is discharged through the sheet discharge port 501, and St30 to St33, which are the normal sheets whose both sides are blank, are discharged through the sheet discharge port 612 as illustrated in FIG. 17. Further, St15 to St29, which are the normal sheets on which the image has been printed only on the front side, are discharged through the sheet discharge port 113, and St1 to St13, which are the normal sheets on which the image has been printed on both sides, are discharged to the discharged sheet stacker 631.

An operation based on the software module of the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The CPU 1001 monitors whether or not there is a misfed sheet among the sheets being conveyed by using the misfed sheet detector 3 while the comprehensive device controller 1 comprehensively controls each processing.

When the misfed sheet is detected by the misfed sheet detector 3, the CPU 1001 causes the misfed sheet detector 3 to immediately notify the head operation controller 2 of the detection, and causes the head operation controller 2 to retract the inkjet head 201 to the retraction position. When the misfed sheet is detected by the misfed sheet detector 3, the CPU 1001 causes the misfed sheet detector 3 to also notify the job manager 4 of the detection, and causes the job manager 4 to temporarily retract the print job data to prepare for the print job after the error recovery processing to be re-input. Further, the CPU 1001 causes the conveyance operation controller 5 to discharge the misfed sheet to the sheet discharge destination and discharge and retract the subsequent sheet that is the normal sheet to the sheet discharge destination according to the printing state.

After the sheet retraction control is completed, the CPU 1001 causes the conveyance operation controller 5 to confirm whether or not there is a remaining sheet on the conveyance path. Then, the CPU 1001 causes the comprehensive device controller 1 to notify the job manager 4 of completion of the error recovery processing and instructs the job manager 4 to re-input the print job, thereby printing the image on the sheet again and ending the operation.

Next, the operation based on the software module of the image forming apparatus 10 will be described in more detail with reference to FIGS. 5 and 19.

The operation of the image forming apparatus 10 illustrated in FIG. 19 is started when the CPU 1001 reads and executes a program of the software module illustrated in FIG. 5, the program being stored in the HDD 1004.

First, the comprehensive device controller 1 notifies the job manager 4 that the print job can be accepted (transmits a message signal indicating “job acceptance Ready”) (S100).

Next, the job manager 4 inputs the print job to the comprehensive device controller 1 (S101).

Next, the comprehensive device controller 1 instructs the misfed sheet detector 3 to start sensing processing by the optical sensor 210 for detecting the misfed sheet (transmits a message signal of “sensing start instruction”) (S102).

Next, the misfed sheet detector 3 notifies the comprehensive device controller 1 that the sensing processing has been started (transmits a message signal of “sensing start”) (S103).

Next, the comprehensive device controller 1 instructs the head operation controller 2 to lower the inkjet head 201 to the printing position in order to print the image on the sheet (transmits a message signal of “head lowering instruction”) (S104).

Next, after lowering the inkjet head 201 to the printing position, the head operation controller 2 notifies the comprehensive device controller 1 of completion of the lowering (transmits a message signal of “head lowering completion”) (S105).

Next, the comprehensive device controller 1 instructs the conveyance operation controller 5 to start conveyance of the sheet (transmits a message signal of “sheet conveyance start instruction”) (S106).

Next, the conveyance operation controller 5 starts sheet feeding control to start sheet feeding from the first stage sheet feeding portion 100a, the second stage sheet feeding portion 100b, or the third stage sheet feeding portion 100c of the sheet feeding portion 100 (S107).

Next, the conveyance operation controller 5 notifies the comprehensive device controller 1 that sheet feeding has been started (transmits a message signal of “sheet feeding start notification”) (S108). As a result, the printing operation is started.

After the start of the printing operation, the misfed sheet detector 3 detects the misfed sheet and determines a position where the edge portion fold or uplift has occurred on the misfed sheet in the conveyance direction (S201).

Next, the misfed sheet detector 3 notifies the comprehensive device controller 1 that the misfed sheet has been detected and the position where the edge portion fold or uplift has occurred in the conveyance direction (transmits a message signal of “misfed sheet detection notification”) (S202). As a result, the comprehensive device controller 1 starts the error recovery processing according to the position where the edge portion fold has occurred in the conveyance direction.

Next, the comprehensive device controller 1 instructs the head operation controller 2 to retract the inkjet head 201 from the printing position to the retraction position (transmits a message signal of “head retraction instruction”) (S203).

Next, the head operation controller 2 performs head retraction control of retracting the inkjet head 201 from the printing position to the retraction position (S204). In a case where both sides of the misfed sheet are blank, the head operation controller 2 returns the inkjet head 201 from the retraction position to the printing position after the misfed sheet passes through the printing portion 200 according to the printing state of the subsequent sheet. After printing the image on the normal sheet, the head operation controller 2 moves the inkjet head 201 from the printing position to the initial position.

Next, the head operation controller 2 notifies the comprehensive device controller 1 of completion of the retraction control for the inkjet head 201 (transmits a message signal of “head retraction completion notification”) (S205).

In addition, in the error recovery processing, the comprehensive device controller 1 instructs the conveyance operation controller 5 to reroute the subsequent sheet from the current conveyance path to the conveyance path to a temporary retraction destination (transmits a message signal of “conveyance rerouting instruction”) (S206).

Next, the conveyance operation controller 5 executes conveyance rerouting control processing of rerouting to discharge and temporarily retract the subsequent sheet (S207). However, in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction, the conveyance operation controller 5 maintains the normal sheet discharge destination without changing the sheet discharge destination of the subsequent sheet that is the normal sheet on which the image has been printed only on the front side, and continues the conveyance processing. In addition, in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the leading edge portion of the misfed sheet in the conveyance direction, the conveyance operation controller 5 maintains the normal sheet discharge destination without changing the sheet discharge destinations of all the subsequent sheets, and continues the conveyance processing.

Next, the conveyance operation controller 5 notifies the comprehensive device controller 1 of completion of the conveyance rerouting control processing after completing the discharge of all the subsequent sheets to the retraction destination or the normal sheet discharge destination (transmits a message signal of “conveyance rerouting completion notification”) (S208).

Furthermore, in the error recovery processing, the comprehensive device controller 1 notifies the job manager 4 of job cancellation in order to retract the print job data (transmits a message signal of “job cancellation notification”) (S209).

Next, the job manager 4 retracts and holds the print job data as print data being printed (S210).

In the above operation, the operation of step S203, the operation of step S206, and the operation of step S209 by the comprehensive device controller 1 are performed in parallel.

Next, the comprehensive device controller 1 instructs the conveyance operation controller 5 to execute remaining sheet detection control processing for confirming whether or not there is a remaining sheet on the conveyance path (transmits a message signal of “remaining sheet detection instruction”) (S301).

Next, the conveyance operation controller 5 executes the remaining sheet detection control processing of confirming whether or not there is a remaining sheet on the conveyance path (S302).

Next, after the remaining sheet detection control processing is completed, the conveyance operation controller 5 notifies the comprehensive device controller 1 of completion of the remaining sheet detection control processing (transmits a message signal of “remaining sheet detection completion notification”) (S303).

Next, the comprehensive device controller 1 notifies the job manager 4 that the error recovery processing has been completed (transmits a message signal of “recovery completion notification”) (S304).

Next, the job manager 4 accepts the print job data being printed, re-inputs the print job data to the comprehensive device controller 1, and resumes the print job, the print job data being retracted and held in the processing of step S210 (S305). At this time, in a case where the image has been printed only on the front side of the misfed sheet detected in S201, the job manager 4 regenerates the print job data such that the image to be printed on the abnormal sheet is printed on the sheet newly conveyed by the conveying portion 700.

An operation of hardware of the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The CPU 1001 starts the printing operation when the print job is received, and starts execution of the misfed sheet detection control processing for detecting the misfed sheet, the print head control processing for printing the image on the sheet, and the sheet conveyance control processing for conveying the sheet.

In a case where the misfed sheet is detected during the printing operation, the CPU 1001 starts the error recovery processing according to the position where the edge portion fold has occurred on the sheet in the conveyance direction and the printing states of the misfed sheet and the subsequent sheet. By starting the error recovery processing, the CPU 1001 retracts the inkjet head 201 and the sheet being conveyed, and executes the conveyance rerouting control processing and the remaining sheet detection control processing.

Thereafter, the CPU 1001 ends the printing operation in a case where the sheet discharge has been completed up to the last page, with no misfed sheet detected, after the re-input print job is received again and the error recovery processing ends. In addition, the CPU 1001 ends the misfed sheet detection control processing, the print head control processing, and the sheet conveyance control processing.

The sheet during the double-sided job is inspected by the optical sensor 210 as to whether or not the sheet is the misfed sheet, and then passes through the inkjet head 201, so that the image is printed on the front side. Further, the sheet on which the image has been printed on the front side is circulated on the conveyance path, conveyed again to the printing portion 200, inspected by the optical sensor 210 as to whether or not the sheet is the misfed sheet for the second time, and then passes through the inkjet head 201, so that the image is printed on the back side.

In a case where the misfed sheet on which the image has not been printed is detected by the first inspection as to whether or not the sheet is the misfed sheet during the double-sided job, it is not necessary to perform re-printing of the image and re-conveyance control for arranging the page order. Therefore, in this case, when the edge portion fold has occurred at the leading edge portion of the misfed sheet in the conveyance direction, the inkjet head 201 retracted to the retraction position is returned to the printing position, and printing of the image on the subsequent sheet is continued. On the other hand, when the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction, the inkjet head 201 retracted to the retraction position is returned to the printing position. Then, printing of the image on the back side of the subsequent sheet on which the image has been printed only on the front side is continued, and the subsequent sheet whose both sides are blank is temporarily discharged and retracted.

In addition, in a case where the misfed sheet on which the image is already printed is detected by the second inspection as to whether or not the sheet is the misfed sheet, the image printed on the misfed sheet is printed on the normal sheet by performing the bitmap shift in order to execute the error recovery processing. In this case, it is necessary to perform the re-conveyance control for arranging the page order. Therefore, in this case, after the inkjet head 201 is retracted and the misfed sheet is discharged, the conveyance is controlled such that the subsequent sheet is also temporarily retracted to the retraction destination different from the retraction destination of the misfed sheet.

Next, the operation of the hardware of the image forming apparatus 10 will be described in more detail with reference to FIGS. 4 and 20.

The operation illustrated in FIG. 20 is started at a timing when the CPU 1001 detects that the print job has been transmitted to the image forming apparatus 10.

First, the CPU 1001 receives the print job from the print server 70 via the local area network 1007 and the network I/F 1006, and stores and holds the print job data in the RAM 1002 (S1001).

Next, the CPU 1001 starts the misfed sheet detection control processing in order to monitor whether or not there is a misfed sheet among the sheets being conveyed according to the operation of step S102 of the operation illustrated in FIG. 19 (S1002). The misfed sheet detection control processing is described below.

Next, the CPU 1001 starts the print head control processing in order to eject the ink onto the sheet and print the image (S1003). The print head control processing is described below.

Next, the CPU 1001 starts the sheet conveyance control processing in order to convey the sheet (S1004). The sheet conveyance control processing is described below.

Next, the CPU 1001 determines whether or not the misfed sheet has been detected based on the electric signal input from the optical sensor 210 in the misfed sheet detection control processing (S1005). Here, only the sheet where the edge portion fold has occurred is detected as the misfed sheet determined in the operation of step S1005.

The misfed sheet determined in the operation of step S1005 is not limited to only the sheet where the edge portion fold has occurred, and may also include the sheet where the uplift has occurred. However, in this case, only the sheet where an uplift amount as a value indicating the abnormality of the sheet where the uplift has occurred exceeds a predetermined value as a threshold is detected. At this time, for example, in a case where the maximum height of the light blocked portion in which the light receiving quantity of the light receiving portion 2102 indicated by the electric signal input from the light receiving portion 2102 is less than the reference value in an uplift direction is larger than a predetermined height, the CPU 1001 determines that the uplift amount of the sheet exceeds the predetermined value.

In a case where the misfed sheet has been detected (step S1005: Yes), the CPU 1001 instructs the inkjet head 201 to move to the retraction position according to the operation of step S203 of the operation illustrated in FIG. 19 (S1006).

Next, the CPU 1001 starts the error recovery processing, and instructs to reroute the subsequent sheet to the conveyance path for conveying the subsequent sheet to the normal sheet discharge destination or retracting the subsequent sheet to the sheet discharge destination as the retraction destination according to the operation of step S206 of the operation illustrated in FIG. 19 (S1007).

Next, the CPU 1001 notifies the print server 70 of the job cancellation via the network I/F 1006 and retracts the print job data being printed according to the operation of step S209 of the operation illustrated in FIG. 19 (S1008).

Next, the CPU 1001 determines whether or not the discharge of the sheet being conveyed has been completed up to the last page (S1009).

In a case where the discharge of the sheet being conveyed has not been completed up to the last page (step S1009: No), the CPU 1001 repeats the processing of step S1009.

On the other hand, in a case where the discharge of the sheet being conveyed has been completed up to the last page (step S1009: Yes), the CPU 1001 executes the remaining sheet detection control processing according to the operation of step S301 of the operation of FIG. 19 (S1010). The remaining sheet detection control processing is described below.

Next, the CPU 1001 determines whether or not there is no remaining sheet (S1011).

In a case where there is a remaining sheet and a notification that the remaining sheet has been detected is received in the remaining sheet detection control processing (step S1011: No), the CPU 1001 notifies a user of remaining sheet information and urges the user to remove the remaining sheet. Thereafter, the CPU 1001 returns to the processing of step S1010.

On the other hand, in a case where there is no remaining sheet and the notification that there is no remaining sheet is received in the remaining sheet detection control processing (step S1011: Yes), the CPU 1001 urges the print server 70 to re-input the print job (S1012).

Next, the CPU 1001 determines whether or not the print job has been re-input from the print server 70 (S1013).

In a case where the print job has not been re-input (step S1012: No), the CPU 1001 repeats the processing of step S1012.

On the other hand, in a case where the print job has been re-input (step S1012: Yes), the CPU 1001 returns to the processing of step S1002.

In a case where the misfed sheet has not been detected in the processing of step S1005 (step S1005: No), the CPU 1001 determines whether or not the sheet discharge has been completed up to the last page (S1014).

In a case where the sheet discharge has not been completed up to the last page (step S1014: No), the CPU 1001 returns to the processing of step S1006.

On the other hand, in a case where the sheet discharge has been completed up to the last page (step S1014: Yes), the CPU 1001 instructs to stop the misfed sheet detection control processing (S1015).

Next, the CPU 1001 instructs to stop the print head control processing (S1016), and then ends the operation.

The misfed sheet detection control processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The misfed sheet detection control processing is processing of detecting whether or not there is a misfed sheet among the sheets being conveyed by the conveying portion 700 by using the optical sensor 210 of the printing portion 200. In the misfed sheet detection control processing, monitoring of the misfed sheet is continued until an instruction to stop the processing is issued, and a message signal of a misfed sheet detection notification is immediately transmitted when the misfed sheet is detected.

Next, the misfed sheet detection control processing will be described in more detail with reference to FIG. 21.

The misfed sheet detection control processing illustrated in FIG. 21 is started at a timing when the operation of step S1002 of the operation illustrated in FIG. 20 is started.

First, the CPU 1001 activates the optical sensor 210 in a case where the optical sensor 210 is not activated, and holds the optical sensor 210 in an activated state in a case where the optical sensor 210 is already activated. The CPU 1001 activates the optical sensor 210 to enable the optical sensor 210 to detect the misfed sheet, thereby performing the monitoring of the misfed sheet (S2001).

Next, the CPU 1001 determines whether or not the misfed sheet has been detected by the optical sensor 210 (S2002).

In a case where the misfed sheet has been detected (step S2002: Yes), the CPU 1001 makes the misfed sheet detection notification (S2003), and then ends the misfed sheet detection control processing.

On the other hand, in a case where the misfed sheet has not been detected by the optical sensor 210 (step S2002: No), the CPU 1001 determines whether or not an instruction to stop the misfed sheet detection control processing by the operation of step S1015 of the operation illustrated in FIG. 20 has been issued (S2004).

In a case where the stop instruction has not been issued (step S2004: No), the CPU 1001 returns to the processing of step S2002.

On the other hand, in a case where the stop instruction has been issued (step S2004: Yes), the CPU 1001 ends the misfed sheet detection control processing.

The print head control processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The print head control processing is processing of moving the inkjet head 201 to the printing position by the head controller 1010 when the printing operation starts, ejecting the ink onto the conveyed sheet from the inkjet head 201, and printing the image on the sheet. Furthermore, the print head control processing is processing of immediately moving and retracting the inkjet head 201 from the printing position to the retraction position by the head controller 1010 when the misfed sheet is detected in order to avoid the collision between the inkjet head 201 and the misfed sheet. The print head control processing is processing of returning the inkjet head 201 from the retraction position to the printing position when the misfed sheet passes through the printing portion 200 in the case of printing the image on the subsequent sheet.

Next, the print head control processing will be described in more detail with reference to FIG. 22.

The print head control processing illustrated in FIG. 22 is started at a timing when the operation of step S1003 of the operation illustrated in FIG. 20 is started.

First, the CPU 1001 controls the head controller 1010 to move the inkjet head 201 to the printing position at which the ink can be ejected onto the sheet according to the operation of step S104 of the operation illustrated in FIG. 19 (S3001).

Next, the CPU 1001 determines whether or not an instruction to move the inkjet head 201 to the retraction position has been issued by the operation of step S1006 of the operation illustrated in FIG. 20 (S3002).

In a case where the instruction to move the inkjet head 201 to the retraction position has been issued (step S3002: Yes), the CPU 1001 controls the head controller 1010 to execute the print head retraction processing (S3003). The print head retraction processing is described below. Thereafter, the CPU 1001 ends the print head control processing.

On the other hand, in a case where the instruction to move the inkjet head 201 to the retraction position has not been issued (step S3002: No), the CPU 1001 determines whether or not the sheet has reached an ink ejection position of the inkjet head 201 (S3004).

In a case where the sheet has not reached the ink ejection position (step S3004: No), the CPU 1001 returns to the processing of step S3002.

On the other hand, in a case where the sheet has reached the ink ejection position (step S3004: Yes), the CPU 1001 controls the head controller 1010 to cause the inkjet head 201 to eject the ink onto the sheet (S3005).

Next, the CPU 1001 determines whether or not an instruction to stop the print head control processing has been issued by the operation of step S1016 of the operation illustrated in FIG. 20 (S3006).

In a case where the instruction to stop the print head control processing has not been issued (step S3006: No), the CPU 1001 returns to the processing of step S3002.

On the other hand, in a case where the instruction to stop the print head control processing has been issued (step S3006: Yes), the CPU 1001 moves the inkjet head 201 to an initial position and ends the print head control processing.

The print head retraction processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The print head retraction processing is processing of immediately retracting the inkjet head 201 to the retraction position in order to avoid the collision between the inkjet head 201 and the misfed sheet in a case where the misfed sheet is detected.

Here, in a case where the image has been printed on the front side of the misfed sheet, it is necessary to print the image printed on the front side of the misfed sheet again on the subsequent sheet which is the normal sheet and perform re-conveyance control so as to arrange the page order. Therefore, in a case where the image has been printed on the front side of the misfed sheet, the image cannot be continuously printed on the subsequent sheet.

On the other hand, in a case where no image has been printed on the misfed sheet, it is not necessary to execute processing of reprinting the image to be printed on the misfed sheet on the subsequent sheet and arranging the page order, and thus, the image can be continuously printed on the subsequent sheet. As described above, in a case where the image can be continuously printed on the subsequent sheet, it is desired to print the image on both sides of the subsequent sheet and complete the sheet discharge.

Therefore, in the print head retraction processing, in a case where no image has been printed on the misfed sheet, the inkjet head 201 retracted to the retraction position is returned to the printing position, and printing of the image on the subsequent sheet is continued. At this time, in the print head retraction processing, printing of the image on all subsequent sheets is continued in a case where the edge portion fold has occurred at the leading edge portion of the misfed sheet in the conveyance direction. On the other hand, in the print head retraction processing, in a case where the edge portion fold has occurred at the leading edge portion of the misfed sheet in the conveyance direction, printing of the image on the back side of the subsequent sheet on which the image has been printed only on the front side is continued.

Next, the print head retraction processing will be described in more detail with reference to FIG. 23.

The print head retraction processing illustrated in FIG. 23 is started at a timing when an affirmative determination (Yes) is made in the processing of step S3002 of the print head control processing illustrated in FIG. 22.

First, in order to avoid the collision between the inkjet head 201 and the misfed sheet, the CPU 1001 controls the head controller 1010 to move the inkjet head 201 from the printing position to the retraction position and waits for the misfed sheet to pass (S3101).

Next, the CPU 1001 determines whether or not both sides of the misfed sheet are blank (S3102).

In a case where the image has been printed only on the front side of the misfed sheet (step S3102: No), the CPU 1001 ends the print head retraction processing.

On the other hand, in a case where both sides of the misfed sheet are blank (step S3102: Yes), the CPU 1001 determines whether or not the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction and the subsequent sheet whose both sides are blank has passed through the inkjet head 201 (S3103).

In a case where the edge portion fold (trailing edge fold) has occurred at the trailing edge portion of the misfed sheet in the conveyance direction and the subsequent sheet whose both sides are blank has passed through the inkjet head 201 (step S3103: Yes), the CPU 1001 ends the print head retraction processing.

On the other hand, in a case where the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction and the subsequent sheet whose both sides are blank has not passed through the inkjet head 201 (step S3103: No), the CPU 1001 moves the inkjet head 201 to the printing position (S3104). At this time, the CPU 1001 moves the inkjet head 201 from the retraction position to the printing position after the misfed sheet passes through the inkjet head 201.

Next, the CPU 1001 determines whether the subsequent sheet has reached the ink ejection position (S3105).

In a case where the subsequent sheet has not reached the ink ejection position (step S3105: No), the CPU 1001 repeats the processing of step S3105 and waits for the subsequent sheet to reach the ink ejection position.

On the other hand, in a case where the subsequent sheet has reached the ink ejection position (step S3105: Yes), the CPU 1001 controls the head controller 1010 to eject the ink onto the subsequent sheet (S3106).

Next, the CPU 1001 determines whether or not all the sheets being conveyed have passed through the inkjet head 201 (S3107).

In a case where all the sheets being conveyed have passed through the inkjet head 201 (step S3107: Yes), the CPU 1001 ends the print head retraction processing.

On the other hand, in a case where not all the sheets being conveyed have passed through the inkjet head 201 (step S3107: No), the CPU 1001 returns to the processing of step S3105.

In the above-described print head retraction processing, whether or not both sides of the misfed sheet are blank and whether or not the image has been printed only on the front side can be determined based on an elapsed time from the sheet feeding start time of the misfed sheet to the passage of the misfed sheet through the inkjet head 201. Time information regarding a time required for the sheet to pass through the inkjet head 201 once from the sheet feeding start time and a time required for the sheet to pass through the inkjet head twice is stored in the ROM 1003 in advance.

The sheet conveyance control processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The sheet conveyance control processing is processing of starting conveyance of the sheet fed from the sheet feeding portion 100 by rotating the conveying roller and executing the conveyance rerouting control processing in a case where an instruction to perform rerouting for changing the conveyance path due to detection of the misfed sheet is issued. Further, the sheet conveyance control processing is processing of notifying that the conveyance of all the sheets has been completed and stopping the conveying roller to end the conveyance of the sheet when the sheet discharge has been completed up to the sheet of the last page.

Next, the sheet conveyance control processing will be described in more detail with reference to FIG. 24.

The sheet conveyance control processing illustrated in FIG. 24 is started at a timing when the operation of step S1004 of the operation illustrated in FIG. 20 is started.

First, the CPU 1001 controls the conveyance controller 1011 to start driving of the conveying roller (S4001).

Next, the CPU 1001 controls the conveyance controller 1011 to cause the sheet feeding portion 100 to start sheet feeding (S4002).

Next, the CPU 1001 determines whether or not an instruction to reroute the subsequent sheet to the conveyance path for retracting the subsequent sheet to the sheet discharge destination has been issued by the operation of step S1007 of the operation illustrated in FIG. 20 (S4003).

In a case where the rerouting instruction has been issued (step S4003: Yes), the CPU 1001 executes the conveyance rerouting control processing (S4004). The conveyance rerouting control processing is described below.

Next, the CPU 1001 determines whether or not the sheet discharge has been completed up to the sheet of the last page (S4005).

In a case where the sheet discharge has not been completed up to the sheet of the last page (step S4005: No), the CPU 1001 returns to the processing of step S4003.

On the other hand, in a case where sheet discharge has been completed up to the sheet of the last page (step S4005: Yes), the CPU 1001 notifies that the discharge of all the sheets has been completed (S4006). Then, the CPU 1001 makes a conveyance rerouting completion notification by the operation of step S208 of the operation illustrated in FIG. 19 to notify that the conveyance rerouting control processing has been completed.

Next, the CPU 1001 controls the conveyance controller 1011 to stop the driving of the conveying roller (S4007), and then ends the sheet conveyance control processing.

On the other hand, in a case where the rerouting instruction has not been issued in step S4003 (step S4003: No), the CPU 1001 skips to the processing of step S4005.

The remaining sheet detection control processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The remaining sheet detection control processing is processing for confirming whether or not an unexpected sheet remains on the conveyance path to confirm that the error recovery processing has been normally executed when the sheet being conveyed is retracted to the sheet discharge destination by the conveyance rerouting control processing caused by the detection of the misfed sheet. In the remaining sheet detection control processing, the conveying roller is driven for a predetermined time to confirm whether or not any of conveyance sensors has detected a sheet remaining on the conveyance path. In the remaining sheet detection control processing, in a case where a sheet has been detected by the conveyance sensor, it is notified that the remaining sheet has been detected, and in a case where no sheet has been detected by the conveyance sensor, it is notified that there is no remaining sheet.

Next, the remaining sheet detection control processing will be described in more detail with reference to FIG. 25.

The remaining sheet detection control processing illustrated in FIG. 25 is started at a timing when an affirmative determination (Yes) is made in the operation of step S1009 of the operation illustrated in FIG. 20.

First, the CPU 1001 controls the conveyance controller 1011 to start driving of the conveying roller (S5001).

Next, the CPU 1001 determines whether or not a remaining sheet has been detected by the conveyance sensor (S5002).

In a case where a remaining sheet has been detected (step S5002: Yes), the CPU 1001 notifies that a remaining sheet has been detected (S5003).

Next, the CPU 1001 controls the conveyance controller 1011 to stop the driving of the conveying roller (S5004), and then ends the remaining sheet detection control processing.

On the other hand, in a case where remaining sheet has been not detected in step S5002 (step S5002: No), the CPU 1001 determines whether or not a predetermined time has elapsed from the detection of the misfed sheet (S5005).

In a case where the predetermined time has not elapsed (step S5005: No), the CPU 1001 returns to the processing of step S5002.

On the other hand, in a case where the predetermined time has elapsed (step S5005: Yes), the CPU 1001 notifies that there is no remaining sheet (S5006), and then executes the processing of step S5004.

After ending the remaining sheet detection control processing illustrated in FIG. 25, the CPU 1001 starts the operation of step S1011 of the operation illustrated in FIG. 20.

The conveyance rerouting control processing executed by the image forming apparatus 10 according to the first embodiment of the present invention will be described in detail.

The conveyance rerouting control processing is processing of selecting and determining the sheet discharge destination according to a position where the sheet being conveyed is present on the conveyance path when the misfed sheet is detected, by using the sheet discharge destination management table illustrated as an example in FIG. 18. The conveyance rerouting control processing is processing of switching a conveyance destination so as to guide the sheet to a designated high-priority sheet discharge destination in a case where the high-priority sheet discharge destination is designated in the sheet discharge destination management table.

Here, the sheet discharge destination management table is a table that manages a plurality of sheet discharge destinations that can be used as the sheet retraction destinations when the misfed sheet is detected. The sheet discharge destination management table stores information of “IndexNo”, “sheet discharge destination”, “distance to branch position”, “conveyance time to branch position”, and “high-priority sheet discharge destination” in association with each other.

“IndexNo” is an identifier for uniquely identifying the sheet discharge destination. “Sheet discharge destination” indicates the sheet discharge destination. “Distance to branch position” indicates a distance to the branch position on the conveyance path for discharging the sheet to the associated sheet discharge destination with a sheet feeding position of the sheet feeding portion 100 as 0 mm. “Conveyance time to branch position” indicates a time required for movement to the branch position on the conveyance path for discharging the sheet to the associated sheet discharge destination at a predetermined conveyance speed with the sheet feeding start time from the sheet feeding portion 100 as 0 second.

In the sheet discharge destination management table illustrated in FIG. 18, a sheet feeding position Q (see FIG. 10) of the sheet feeding cassette 132 is 0 mm. Further, the branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 1 is the branch position B1. The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 2 is the branch position B2. The branch position corresponding to the distances to the branch position and the conveyance times to the branch position of IndexNo. 3 and IndexNo. 5 is the branch position B3. The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 4 is the branch position B4.

The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 6 is the branch position B5. The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 7 is the branch position B6. The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 8 is the branch position B7. The branch position corresponding to the distance to the branch position and the conveyance time to the branch position of IndexNo. 9 is the branch position B8.

As for the sheet discharge destination of the sheet discharge destination management table, the sheet feeding portion 3TOP tray 134 is the sheet discharge destination of sheet discharge through the sheet discharge port 133, the sheet feeding portion 2TOP tray 124 is the sheet discharge destination of sheet discharge through the sheet discharge port 123, and the sheet feeding portion 1TOP tray 114 is the sheet discharge destination of sheet discharge through the sheet discharge port 113. Further, the fixing portion double-sided tray is the sheet discharge destination of sheet discharge through the sheet discharge port 301, and the reversing portion TOP tray 502 is the sheet discharge destination of sheet discharge through the sheet discharge port 501. Further, the sheet discharge portion 1TOP tray 613 is the sheet discharge destination of sheet discharge through the sheet discharge port 612, the sheet discharge portion 2TOP tray 623 is the sheet discharge destination of sheet discharge through the sheet discharge port 622, and the sheet discharge portion 3TOP tray 633 is the sheet discharge destination of sheet discharge through the sheet discharge port 632.

In the sheet discharge destination management table illustrated in FIG. 18, the sheet discharge destination for the sheet present upstream of the sheet discharge portion 1TOP tray 613 in the conveyance direction when the misfed sheet is detected is the sheet discharge portion 1TOP tray 613. In the sheet discharge destination management table illustrated in FIG. 18, the sheet discharge destination for the sheet present between the sheet discharge portion 1TOP tray 613 and the sheet discharge portion 2TOP tray 623 when the misfed sheet is detected is the sheet discharge portion 2TOP tray 623. Further, in the sheet discharge destination management table illustrated in FIG. 18, the sheet discharge destination for the sheet present between the sheet discharge portion 2TOP tray 623 and the sheet discharge portion 3TOP tray 633 when the misfed sheet is detected is the sheet discharge portion 3TOP tray 633.

On the other hand, in the sheet discharge destination management table illustrated in FIG. 18, the high-priority sheet discharge destination for the sheet being conveyed between the sheet feeding cassette 132 and the branch position B3 to the sheet discharge portion 1TOP tray 613 when the misfed sheet is detected is the sheet discharge portion 1TOP tray 613. As a result, the image forming apparatus 10 can collectively discharge, to the same sheet discharge portion 1TOP tray 613, the sheets being conveyed between the sheet feeding cassette 132 and the branch position B3 to the sheet discharge portion 1TOP tray 613.

Further, in the sheet discharge destination management table illustrated in FIG. 18, the fixing portion double-sided tray is set as the sheet discharge destination of the sheet present in a range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray when the misfed sheet is detected. However, the misfed sheet and the normal sheet present in the range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray are desirably discharged to different sheet discharge destinations. Therefore, in the sheet discharge destination management table illustrated in FIG. 18, the high-priority sheet discharge destination of the misfed sheet present in the range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray is set to the reversing portion TOP tray 502.

In the sheet discharge destination management table illustrated in FIG. 18, the high-priority sheet discharge destination of the normal sheet present in the range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray is set to the sheet feeding portion 1TOP tray 114.

Since the normal sheet present in the range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray has passed through the printing portion 200 once, the image is printed only on the front side. The sheet on which the image has been printed only on the front side other than the normal sheet present in the range between the branch position B3 to the sheet discharge portion 1TOP tray 613 and the branch position B4 to the fixing portion double-sided tray is also present downstream of the branch position B4 to the fixing portion double-sided tray in the conveyance direction. In the sheet discharge destination management table illustrated in FIG. 18, the high-priority sheet discharge destination of the normal sheet on which the image has been printed only on the front side and which is present downstream of the branch position B4 in the conveyance direction is set to the same sheet feeding portion 1TOP tray 114 as that for the normal sheet present upstream of the branch position B4 in the conveyance direction.

Only the normal sheet on which the image has been printed on both sides (having both sides printed) is present downstream of the branch position B3 to the sheet feeding portion 1TOP tray 114 in the second round in the conveyance direction. Therefore, there is no problem even if the normal sheet present downstream of the branch position B3 to the sheet feeding portion 1TOP tray 114 in the second round in the conveyance direction is discharged as usual, and it is not necessary to switch the sheet discharge destination. Accordingly, in the sheet discharge destination management table illustrated in FIG. 18, the high-priority sheet discharge destination of the normal sheet present downstream of the branch position B3 to the sheet feeding portion 1TOP tray 114 in the second round in the conveyance direction is set to a normal sheet discharge tray. Here, the normal sheet discharge tray is the discharged sheet stacker 611, the discharged sheet stacker 621, or the discharged sheet stacker 631.

The sheet discharge destination management table is set and stored in advance for each of the sheet feeding cassettes 110 to 112, 120 to 122, and 130 to 132. In the present embodiment, a description of an example of the sheet discharge destination management table set corresponding to each of the sheet feeding cassettes 110 to 112, 120 to 122, 130, and 131 other than the sheet feeding cassette 132 is omitted.

In the conveyance rerouting control processing, the subsequent sheet is rerouted in a case where the image has been printed only on the front side of the misfed sheet. In addition, in the conveyance rerouting control processing, in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the leading edge portion in the conveyance direction, the subsequent sheet is discharged to the normal sheet discharge destination without performing the rerouting of the subsequent sheet. Further, in the conveyance rerouting control processing, in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the trailing edge portion in the conveyance direction, the subsequent sheet whose both sides are blank is rerouted, and the subsequent sheet whose both sides are blank is discharged and retracted to the sheet discharge destination different from the sheet discharge destination of the misfed sheet.

The conveyance rerouting control processing is not limited to such processing, and in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the trailing edge portion in the conveyance direction, the sheet may be normally conveyed as it is and discharged to the normal sheet discharge destination without performing the rerouting of the subsequent sheet whose both sides are blank.

Next, the conveyance rerouting control processing will be described in more detail with reference to FIGS. 18 and 26.

The conveyance rerouting control processing illustrated in FIG. 26 is started at a timing when an affirmative determination (Yes) is made in the processing of step S4003 of the sheet conveyance control processing illustrated in FIG. 24.

First, the CPU 1001 determines whether or not the image has been printed only on the front side of the misfed sheet (the misfed sheet has been printed on one side) (S4101).

In a case where both sides of the misfed sheet are blank (step S4101: No), the CPU 1001 determines whether or not both sides of the subsequent sheet that is a sheet discharge control target are blank and the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction (the trailing edge fold has occurred on the misfed sheet) (S4102).

In a case where both sides of the subsequent sheet that is the sheet discharge control target are blank and the edge portion fold has not occurred at the trailing edge portion of the misfed sheet in the conveyance direction (step S4102: No), the CPU 1001 determines that there is no change in sheet discharge destination of the subsequent sheet that is the sheet discharge control target (S4103).

Next, the CPU 1001 determines whether rerouting of all the sheets being conveyed has been completed (S4104).

In a case where the rerouting of all the sheets being conveyed has been completed (step S4104: Yes), the CPU 1001 ends the conveyance rerouting control processing.

On the other hand, in a case where the rerouting of all the sheets being conveyed has not been completed (step S4104: No), the CPU 1001 returns to the processing of step S4101.

In addition, in a case where the image has been printed only on the front side of the misfed sheet (step S4101: Yes), the CPU 1001 acquires an elapsed time from the sheet feeding start time of the subsequent sheet that is the sheet discharge control target to the current time (S4105). The elapsed time from the sheet feeding start time to the current time is hereinafter referred to as the “elapsed time from the sheet feeding start time”.

Next, the CPU 1001 determines whether or not there is a sheet discharge destination (unconfirmed sheet discharge destination) that is not referred to in the sheet discharge destination management table (S4106). At this time, the CPU 1001 determines whether or not there is a sheet discharge destination that is not referred to in order from IndexNo. 1.

In a case where there is a sheet discharge destination that is not referred to (step S4106: Yes), the CPU 1001 refers to the sheet discharge destination that is not referred to in the sheet discharge destination management table (S4107).

Next, the CPU 1001 compares the elapsed time from the sheet feeding start time acquired in step S4105 with “conveyance time to branch position” being referred to in the sheet discharge destination management table. Then, the CPU 1001 determines whether or not the elapsed time from the sheet feeding start time acquired in step S4105 is earlier than “conveyance time to branch position” being referred to (S4108). In this manner, the CPU 1001 determines a position of the sheet that is the sheet discharge control target by using the elapsed time from the sheet feeding start time.

In a case where the acquired elapsed time from the sheet feeding start time is after “conveyance time to branch position” being referred to (step S4108: No), the CPU 1001 advances IndexNo that is being referred to in the sheet discharge destination management table by one, and returns to the processing of step S4106.

On the other hand, in a case where the acquired elapsed time from the sheet feeding start time is earlier than “conveyance time to branch position” being referred to (step S4108: Yes), the CPU 1001 determines whether or not the high-priority sheet discharge destination is associated with the sheet discharge destination being referred to (S4109).

In a case where the high-priority sheet discharge destination is associated with the sheet discharge destination associated with IndexNo being referred to (step S4109: Yes), the CPU 1001 changes the conveyance path such that the sheet that is the sheet discharge control target is discharged to the associated high-priority sheet discharge destination (S4110). Thereafter, the CPU 1001 proceeds to the processing of step S4104.

For example, in a case where IndexNo. 3 is referred to, the CPU 1001 changes the conveyance path such that the sheet that is the sheet discharge control target is discharged to the “sheet discharge portion 1TOP tray 613” that is the high-priority sheet discharge destination associated with IndexNo. 3. As described above, in a case where the sheet can be discharged to the high-priority sheet discharge destination, the CPU 1001 discharges the sheet that is the sheet discharge control target to the associated high-priority sheet discharge destination.

Here, the high-priority sheet discharge destination is the sheet discharge destination that has a short downtime at the time of completion of sheet discharge and is designated for collective sheet discharge for each printing state in which the sheet that is the sheet discharge control target is the misfed sheet, the normal sheet whose both sides are blank, or the normal sheet on which the image has been printed only on the front side.

As described above, the CPU 1001 uses the sheet discharge destination management table when executing the conveyance rerouting control processing to select the sheet discharge destination of the subsequent sheet according to the printing state of the misfed sheet and the position where the edge portion fold or uplift has occurred. As a result, it is possible to calculate the sheet discharge destination to be selected as the sheet discharge destination according to a position of the sheet that is the sheet discharge control target on the conveyance path when the misfed sheet is detected.

In addition, in a case where the high-priority sheet discharge destination is not associated with the sheet discharge destination being referred to in the processing of step S4109 (step S4109: No), the CPU 1001 changes the conveyance path such that the subsequent sheet that is the sheet discharge control target is discharged to the sheet discharge destination being referred to (S4111). Thereafter, the CPU 1001 executes the processing of step S4104. As a result, the CPU 1001 discharges the subsequent sheet present within a predetermined range specified by the elapsed time from the sheet feeding start time when the misfed sheet is detected to the closest sheet discharge destination positioned downstream of the predetermined range in the conveyance direction by using the sheet discharge destination management table.

In a case where there is no sheet discharge destination that is not referred to in the processing of step S4106 (step S4106: No), the CPU 1001 determines that there is no sheet discharge destination and stops sheet conveyance (S4112). A case where there is no sheet discharge destination that is not referred to means a case where the sheet has passed through the branch positions to all the sheet discharge destinations. Thereafter, the CPU 1001 executes the processing of step S4104.

Furthermore, in a case where both sides of the subsequent sheet that is the sheet discharge control target are blank and the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction in the processing of step S4102 (step S4102: Yes), the CPU 1001 proceeds to the processing of step S4105.

By executing the conveyance rerouting control processing, it is possible to select the sheet discharge destination closest to the sheet being conveyed based on the elapsed time from the sheet feeding start time of the sheet being conveyed when the misfed sheet is detected. In addition, by referring to the sheet discharge destination management table, it is possible to implement control to switch the sheet discharge destination including the sheet discharge destination to be preferentially selected as the temporary retraction destination of the sheet being conveyed according to the position where the sheet that is the sheet discharge control target is present when the misfed sheet is detected.

In the processing of step S4102 of the conveyance rerouting control processing described above, in a case where both sides of the subsequent sheet that is the sheet discharge control target are blank and the edge portion fold has occurred at the trailing edge portion of the misfed sheet in the conveyance direction, the subsequent sheet whose both sides are blank is temporarily retracted to the sheet discharge destination. However, the present invention is not limited thereto, and in the processing of step S4102, in a case where both sides of the subsequent sheet that is the sheet discharge control target are blank and the edge portion fold has not occurred at the trailing edge portion of the misfed sheet in the conveyance direction, conveyance of the subsequent sheet whose both sides are blank may be continued. In this case, the image is printed on both sides of the subsequent sheet whose both sides are blank, and the subsequent sheet on which the image has been printed on both sides is discharged to the normal sheet discharge destination.

As described above, in a case where the misfed sheet on which the image has not been printed is detected, the inkjet head 201 is retracted to the retraction position and then returned to the printing position, printing of the image on the subsequent sheet is resumed, and the subsequent sheet is discharged to the normal sheet discharge destination to execute the error recovery processing. By executing such processing, the downtime may be shortened.

In the present embodiment, the sheet being conveyed is discharged to any one of a plurality of sheet discharge destinations according to the position where the edge portion fold or uplift has occurred on the sheet where the edge portion fold or uplift detected by the optical sensor 210 has occurred. The plurality of sheet discharge destinations includes the sheet feeding portion 1TOP tray 114, the sheet feeding portion 2TOP tray 124, the sheet feeding portion 3TOP tray 134, the fixing portion double-sided tray, the reversing portion TOP tray 502, the sheet discharge portion 1TOP tray 613, the sheet discharge portion 2TOP tray 623, and the sheet discharge portion 3TOP tray 633. As a result, when the edge portion fold or uplift of the sheet is detected, recovery is performed according to the position where the edge portion fold or uplift of the sheet has occurred, so that recovery when the edge portion fold or uplift of the sheet is detected can be appropriately performed.

Second Embodiment

A configuration of an image forming apparatus according to a second embodiment of the present invention is the same as those in FIGS. 1 and 2, and thus a description thereof will be omitted. In addition, since an operation based on software of the image forming apparatus according to the present embodiment is the same as the operation illustrated in FIG. 13, a description thereof will be omitted. Furthermore, since an operation other than conveyance rerouting control processing in an operation of hardware of the image forming apparatus according to the present embodiment is the same as that in FIG. 14, a description of the operation other than the conveyance rerouting control processing will be omitted.

The conveyance rerouting control processing executed by the image forming apparatus according to the second embodiment of the present invention will be described in detail.

The conveyance rerouting control processing according to the present embodiment is processing of determining a printing state of a sheet according to the number of times the sheet that is a sheet discharge control target has passed through a printing portion 200, and dynamically determining a sheet discharge destination according to the determined printing state. In the conveyance rerouting control processing according to the present embodiment, processing corresponding to the printing state of a misfed sheet is executed, and the sheet discharge destination to be preferentially selected is dynamically determined according to a position of a subsequent sheet that is the sheet discharge control target when the misfed sheet is detected.

In the conveyance rerouting control processing, the misfed sheet is discharged to a specific sheet discharge destination. In addition, the number of times the sheet has passed through the printing portion 200 is determined by comparing an elapsed time from a sheet feeding start time of the sheet that is the sheet discharge control target with a time required for the sheet to pass through the printing portion 200 once from the sheet feeding start time and a time required for the sheet to pass through the printing portion 200 twice. At this time, time information regarding the time required for the sheet to pass through the printing portion 200 once from the sheet feeding start time and the time required for the sheet to pass through the printing portion twice is stored in a ROM 1003 in advance. As a result, a position of the sheet that is the sheet discharge control target can be estimated from the elapsed time from the sheet feeding start time.

Specifically, in a case where the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target is equal to or shorter than the time required for the sheet to pass through the printing portion 200 once, the number of times the sheet has passed through the printing portion 200 is determined to be 0 times. In addition, in a case where the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target is longer than the time required for the sheet to pass through the printing portion 200 once and is equal to or shorter than the time required for the sheet to pass through the printing portion 200 twice, the number of times the sheet has passed through the printing portion 200 is determined to be one time. Furthermore, in a case where the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target is longer than the time required for the sheet to pass through the printing portion 200 twice, the number of times the sheet has passed through the printing portion 200 is determined to be two times.

Further, the sheet discharge destination with the shortest downtime is selected according to the position of the sheet that is the sheet discharge control target. Specifically, the misfed sheet is discharged to a reversing portion TOP tray 502, and a normal sheet that has passed through the printing portion 200 0 times is discharged to a sheet discharge portion 1TOP tray 613 positioned at the closest position. In addition, the normal sheet that has passed through the printing portion 200 once is discharged to a sheet feeding portion 1TOP tray 114 positioned at the closest position, and the normal sheet that has passed through the printing portion 200 twice is discharged to a normal sheet discharge destination.

The sheet discharge destination is not limited to the above, and can be changed to the sheet discharge destination from which a user can easily reuse the retracted normal sheet according to a conveyance path configuration of an image forming apparatus 10 such as a configuration additionally including an inspection machine or a finisher. Depending on the configuration of the apparatus, the sheet discharge destination may be switched for each process such as an image forming process, a fixing process, a cooling process, and a reversing process for the sheet.

Furthermore, in a case where both sides of the misfed sheet are blank, the subsequent sheet on which an image has been printed only on a front side and which has passed through the printing portion 200 once is continuously conveyed as it is, and is discharged to the normal sheet discharge destination regardless of the position where an edge portion fold has occurred on the misfed. The subsequent sheet which has passed through the printing portion 200 0 times and of which both sides are blank is discharged and retracted to a changed sheet discharge destination, or is continuously conveyed as it is and discharged to the normal sheet discharge destination, according to the printing state of the misfed sheet and the position where the edge portion fold has occurred on the misfed sheet.

In a case where the image has been printed only on the front side of the misfed sheet, the subsequent sheet is discharged and retracted to the changed sheet discharge destination. In a case where both sides of the misfed sheet are blank, the subsequent sheet may be continuously conveyed and discharged to the normal sheet discharge destination regardless of the printing state of the subsequent sheet.

Subsequently, the conveyance rerouting control processing according to the present embodiment will be described in more detail with reference to FIG. 27.

The conveyance rerouting control processing illustrated in FIG. 27 is started at a timing when an affirmative determination (Yes) is made in the processing of step S4003 of the sheet conveyance control processing illustrated in FIG. 24.

First, a CPU 1001 acquires the elapsed time from the sheet feeding start time (S5101).

Next, the CPU 1001 determines whether or not the sheet that is the sheet discharge control target is the misfed sheet (S5102).

In a case where the sheet is the misfed sheet (step S5102: Yes), the CPU 1001 controls a conveyance controller 1011 to change a conveyance path such that the misfed sheet is discharged to the reversing portion TOP tray 502 (S5103).

Next, the CPU 1001 determines whether or not rerouting of all the sheets being conveyed has been completed (S5104).

In a case where the rerouting of all the sheets being conveyed has been completed (S5104: Yes), the CPU 1001 ends the conveyance rerouting control processing.

On the other hand, in a case where the rerouting of all the sheets being conveyed has not been completed (step S5104: No), the CPU 1001 returns to the processing of step S5101.

In addition, in a case where the sheet is not the misfed sheet in the processing of step S5102 (step S5102: No), the CPU 1001 determines whether or not the image has been printed on both sides of the sheet that is the sheet discharge control target (the sheet has been printed on both sides) (S5105).

In this case, the CPU 1001 determines whether or not the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target acquired in the processing of step S5101 is longer than the time required for the sheet to pass through the printing portion 200 twice.

In a case where the image has been printed on both sides of the sheet that is the sheet discharge control target (step S5105: Yes), the CPU 1001 selects a sheet discharge port through which the sheet is to be discharged to the normal sheet discharge destination (S5106).

In this case, the CPU 1001 determines that the image has been printed on both sides of the sheet that is the sheet discharge control target based on the longer elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target than the time required for the sheet to pass through the printing portion 200 twice. Thereafter, the CPU 1001 executes the processing of step S5104.

In a case where the image has not been printed on both sides of the sheet that is the sheet discharge control target (step S5105: No), the CPU 1001 determines whether or not the image has been printed only on the front side of the sheet that is the sheet discharge control target (the sheet has been printed on one side) (S5107).

In this case, the CPU 1001 determines that the image has not been printed on both sides of the sheet that is the sheet discharge control target based on the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target, the elapsed time being equal to or shorter than the time required for the sheet to pass through the printing portion 200 twice. In addition, the CPU 1001 determines whether or not the image has been printed only on the front side of the sheet that is the sheet discharge control target by determining whether or not the elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target is longer than the time required for the sheet to pass through the printing portion 200 once.

In a case where the image has been printed only on the front side of the sheet that is the sheet discharge control target (step S5107: Yes), the CPU 1001 determines whether or not the image has been printed only on the front side of the misfed sheet (the misfed sheet has been printed on one side) (S5108).

In this case, the CPU 1001 determines that the image has been printed only on the front side of the sheet that is the sheet discharge control target based on the longer elapsed time from the sheet feeding start time of the sheet that is the sheet discharge control target than the time required for the sheet to pass through the printing portion 200 once. In addition, the CPU 1001 determines whether or not the image has been printed only on the front side of the misfed sheet by determining whether or not the elapsed time from the sheet feeding start time of the misfed sheet is longer than the time required for the sheet to pass through the printing portion 200 once.

In a case where the image has been printed only on the front side of the misfed sheet (step S5108: Yes), the CPU 1001 changes the conveyance path such that the sheet that is the sheet discharge control target is discharged to the sheet discharge destination positioned at the closest downstream position in the conveyance direction other than the reversing portion TOP tray 502 (S5109).

In this case, the CPU 1001 determines that the image has been printed only on the front side of the misfed sheet based on the longer elapsed time from the sheet feeding start time of the misfed sheet than the time required for the sheet to pass through the printing portion 200 once. In addition, the sheet discharge destination positioned at the closest position in this case is the sheet discharge destination positioned at the closest position that is downstream of the position of the sheet that is the sheet discharge control target when the misfed sheet is detected in the conveyance direction, and is, for example, the sheet discharge portion 1TOP tray 613. Thereafter, the CPU 1001 executes the processing of step S5104.

On the other hand, in a case where both sides of the misfed sheet are blank (step S5108: No), the CPU 1001 does not change the sheet discharge destination of the sheet that is the sheet discharge control target and maintains the normal sheet discharge destination (S5110), and then executes the processing of step S5104. In this case, the CPU 1001 determines that both sides of the misfed sheet are blank based on the elapsed time from the sheet feeding start time of the misfed sheet, the elapsed time being equal to or shorter than the time required for the sheet to pass through the printing portion 200 once.

Further, in a case where both sides of the sheet that is the sheet discharge control target are blank (step S5107: No), the CPU 1001 determines whether or not both sides of the misfed sheet are blank and the edge portion fold has occurred at a leading edge portion in the conveyance direction (S5111). In this case, the CPU 1001 determines that both sides of the sheet that is the sheet discharge control target are blank based on the fact that the image has not been printed on both sides of the sheet that is the sheet discharge control target and the image has not been printed only on the front side.

In a case where both sides of the misfed sheet are blank and the edge portion fold has not occurred at the leading edge portion in the conveyance direction (step S5111: No), the CPU 1001 changes the conveyance path (S5112). In this case, the CPU 1001 changes the conveyance path such that the sheet that is the sheet discharge control target is discharged to the sheet discharge destination positioned at the closest position that is upstream of the printing portion 200 in the conveyance direction. Thereafter, the CPU 1001 executes the processing of step S5104.

In this case, the CPU 1001 determines that both sides of the misfed sheet are blank based on the elapsed time from the sheet feeding start time of the misfed sheet, the elapsed time being equal to or shorter than the time required for the sheet to pass through the printing portion 200 once. Furthermore, the sheet discharge destination positioned at the closest position in this case is the sheet discharge destination positioned at the closest position that is upstream of the printing portion 200 in the conveyance direction and downstream of the position of the sheet that is the sheet discharge control target when the misfed sheet is detected in the conveyance direction, and is, for example, the sheet feeding portion 1TOP tray 114.

On the other hand, in a case where both sides of the misfed sheet are blank and the edge portion fold has occurred at the leading edge portion in the conveyance direction (step S5111: Yes), the CPU 1001 does not change the sheet discharge destination of the sheet that is the sheet discharge control target and maintains the normal sheet discharge destination (S5113). Thereafter, the CPU 1001 executes the processing of step S5104.

As described above, control of dynamically switching the sheet discharge destination according to the position where the sheet that is the control target is present is implemented by executing the conveyance rerouting control processing according to the printing state of the misfed sheet.

In the present embodiment, a blank state, a single-sided printing state, or a double-sided printing state is determined based on the number of times the conveyed sheet has passed through the printing portion 200. As a result, in the present embodiment, the effects of the first embodiment described above can be achieved, and a sheet discharge destination management table can be made unnecessary, and a simple configuration can be achieved.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Specifically, in the first and second embodiments, the misfed sheet and the subsequent sheet are discharged to different sheet discharge destinations, but the present invention is not limited thereto, and the misfed sheet and the subsequent sheet may be discharged to the same sheet discharge destination.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2023-217629, filed Dec. 25, 2023, which is hereby incorporated by reference herein in its entirety.

INKJET RECORDING APPARATUS

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