SHEET CONVEYANCE APPARATUS, IMAGE READING APPARATUS, AND IMAGE FORMING APPARATUS

BACKGROUND
Field

The present disclosure relates to a sheet conveyance apparatus that conveys a sheet, an image reading apparatus that reads an image on a sheet, and an image forming apparatus that forms an image on a recording medium.

Description of the Related Art

As an image reading apparatus mounted on a copying machine, a facsimile apparatus, a digital multi-function peripheral, and the like, an auto document feeder (ADF) that reads an image on a document while conveying the document has heretofore been known. Such an ADF feeds a plurality of documents stacked on a document tray by separating the documents one by one. Accordingly, the ADF cannot feed a plurality of documents bound with a staple (such documents are referred to as bound documents or stapled documents) by separating the documents one by one. Feeding of such bound documents may damage the documents due to the separation operation.

In this regard, Japanese Patent Application Laid-Open No. 2021-064849 discusses an image reading apparatus having a configuration in which skew of documents is detected by a plurality of skew detection sensors located side by side in a width direction, to thereby detect bound documents. If bound documents are fed, an uppermost document is rotated around the staple. Accordingly, detecting skew of documents makes it possible to determine whether bound documents are fed.

As a function of the ADF, a different-width mixed stacking mode (also simply referred to as a mixed stacking mode) for feeding a plurality of documents with different widths is known. In the different-width mixed stacking mode, documents with a smaller width are stacked at a position closer to one side in the width direction (at a position deviated from the center of conveyance).

Accordingly, in the case of detecting bound documents by the above-described method in the different-width mixed stacking mode, documents with a smaller width do not pass through one of the skew detection sensors, so that the documents can be erroneously detected as bound documents. In this regard, Japanese Patent Application Laid-Open No. 2021-064849 discusses a configuration in which a notification indicating that there is a possibility that set documents may include documents with different widths is transmitted in a case where skew of documents is detected.

However, a user needs to perform a plurality of operations to set the different-width mixed stacking mode after skew of documents is detected. For example, after cancelling the current job, the user needs to start from a standby screen for a job, such as a copying job, shift to a mode setting screen for selecting a function to set the different-width mixed stacking mode, and then come back to the standby screen again. Thus, the operation for setting the different-width mixed stacking mode after skew of documents is detected is troublesome for the user, which leads to deterioration in operability.

SUMMARY

Accordingly, the present disclosure is directed to providing an image reading apparatus and an image forming apparatus that facilitate setting of a different-width mixed stacking mode after skew of documents (bound documents) is detected, thereby improving the operability.

According to some embodiments, a sheet conveyance apparatus includes a stacking tray on which a sheet is stacked, a conveyance roller configured to convey the sheet stacked on the stacking tray, a first sensor configured to detect the sheet conveyed by the conveyance roller, a second sensor configured to detect the sheet conveyed by the conveyance roller, the second sensor and the first sensor being located side by side in a width direction orthogonal to a conveyance direction of the sheet, a controller configured to execute stopping processing to stop conveyance of the sheet by the conveyance roller in a case where one of the first sensor and the second sensor does not detect the sheet before a predetermined time period elapses since the sheet is detected by the other of the first sensor and the second sensor, and a display portion configured to display a predetermined screen configured to set a different-width mixed stacking mode, which is a mode to be used when a plurality of sheets with different widths is stacked on the stacking tray, in a case where the stopping processing is executed based on the first sensor and the second sensor.

According to another aspect of the present disclosure, a sheet conveyance apparatus includes a stacking tray on which a sheet is stacked, a conveyance roller configured to convey the sheet stacked on the stacking tray, a first sensor configured to detect the sheet conveyed by the conveyance roller, a second sensor configured to detect the sheet conveyed by the conveyance roller, the second sensor and the first sensor being located side by side in a width direction orthogonal to a conveyance direction of the sheet, a controller configured to determine whether the sheet conveyed by the conveyance roller is skewed based on the first sensor and the second sensor, and a display portion configured to display a predetermined screen configured to set a different-width mixed stacking mode, which is a mode to be used when a plurality of sheets with different widths is stacked on the stacking tray, in a case where the controller determines that the sheet conveyed by the conveyance roller is skewed.

According to still another aspect of the present disclosure, a sheet conveyance apparatus includes a stacking tray on which sheets are stacked, a conveyance roller configured to convey the sheets stacked on the stacking tray, a first sensor configured to detect the sheets conveyed by the conveyance roller, a second sensor configured to detect the sheets conveyed by the conveyance roller, the second sensor and the first sensor being located side by side in a width direction orthogonal to a conveyance direction of the sheets, a controller configured to determine whether the sheets conveyed by the conveyance roller are bound with a staple based on the first sensor and the second sensor, and a display portion configured to display a predetermined screen configured to set a different-width mixed stacking mode, which is mode to be used when a plurality of sheets with different widths is stacked on the stacking tray, in a case where the controller determines that the sheets conveyed by the conveyance roller are bound with a staple.

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

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a printer.

FIG. 2 is a schematic sectional view of an image reading apparatus.

FIG. 3 is a block diagram illustrating the image reading apparatus and a controller.

FIG. 4A is a top view of an auto document feeder (ADF) in a normal mode, and FIG. 4B is a top view of the ADF in a different-width mixed stacking mode.

FIG. 5 illustrates a motion of documents when bound documents are fed.

FIG. 6 illustrates a motion of documents when documents with different widths are fed.

FIG. 7 illustrates an example of a screen to be displayed on an operation unit when a document feed operation is stopped.

FIG. 8A illustrates an example of a standby screen to be displayed in a copy mode, FIG. 8B illustrates an example of a setting screen for “other functions”, and FIG. 8C illustrates an example of a setting screen for “mixed document stacking”.

FIG. 9A is a flowchart illustrating processing to be executed by a central processing unit (CPU) of the image reading apparatus, and FIG. 9B is a flowchart illustrating processing to be executed by a CPU of the controller.

FIGS. 10A and 10B are explanatory diagrams each illustrating document edge detection processing.

FIGS. 11A and 11B each explanatory diagrams each illustrating white filling processing.

FIGS. 12A and 12B each illustrate an example of a screen to be displayed on the operation unit when the document feed operation is stopped.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the present disclosure will be described below with reference to the accompanying drawings.

Image Forming Apparatus

A printer 1001 will be described as an example of an image forming apparatus according to an exemplary embodiment with reference to FIG. 1. FIG. 1 is a sectional view of the printer 1001. In the following description, a side where a user faces an operation unit 506 to perform various input/setting operations on the printer 1001 is referred to as a “front side” of the printer 1001, and a back side of the printer 1001 is defined as a “back side”. In other words, FIG. 1 illustrates an internal configuration of the printer 1001 as viewed from the front side.

The printer 1001 includes a printer body 1001A and an image reading apparatus 1005 that is located above the printer body 1001A. The operation unit 506 includes a touch panel and functions as a display portion that receives an instruction from the user and displays information for the user.

The image reading apparatus 1005 includes a scanner unit 100 and an auto document feeder (ADF) 200. The scanner unit 100 reads an image on a document D by optically scanning the document D conveyed by the ADF 200. The document D conveyed by the ADF 200 is, for example, a sheet such as plain paper or thin paper. Image data converted into an electric signal by the image reading apparatus 1005 is transferred to a controller 500 provided in the printer body 1001A (image forming apparatus body) via a control unit 160. The printer 1001 is configured to execute a copy mode for forming an image on a sheet P (recording medium) based on image information read by the image reading apparatus 1005, and a scan mode for transmitting image data read by the image reading apparatus 1005 to an external apparatus.

The printer body 1001A includes an image forming unit 1033 for forming an image on the sheet P, and a sheet feeding unit 1006 for feeding the sheet P to the image forming unit 1033. The sheet feeding unit 1006 includes sheet storage units 1037a, 1037b, 1037c, and 1037d that are configured to store sheets with different sizes. The sheets P stored in the sheet storage units 1037a, 1037b, 1037c, and 1037d are picked up and fed by pickup rollers 1002a, 1002b, 1002c, and 1002d. The sheets P are separated one by one by feed rollers 1003a, 1003b, 1003c, and 1003d and retard rollers 1004a, 1004b, 1004c, and 1004d, and are fed to a conveyance roller pair 1031. The sheets P are further conveyed to a registration roller pair 1036 by a plurality of conveyance roller pairs 1031 located along a sheet conveyance path 1007.

A manual feed tray 1037e is located on a side portion of the printer body 1001A. The sheets P that are stacked on the manual feed tray 1037e by the user are fed into the printer body 1001A by feed rollers 1038, and are further conveyed to the registration roller pair 1036. A leading edge of each sheet P contacts a nip portion of the registration roller pair 1036 in a stopped state, thereby correcting skew of the sheet P. The registration roller pair 1036 starts to rotate in accordance with progress of a toner image forming operation by the image forming unit 1033 and conveys the sheet P to the image forming unit 1033.

The image forming unit 1033 forms a toner image on the sheet P by an electrophotographic method. The image forming unit 1033 includes a photosensitive drum 1021 as a photosensitive member. The photosensitive drum 1021 is rotatable along a conveyance direction of the sheet P. A charging device 1018, an exposure device 1023, a developing device 1024, a transfer charging device 1025, a separation charging device 1026, and a cleaner 1027 are provided in the vicinity of the photosensitive drum 1021. The charging device 1018 uniformly charges the surface of the rotating photosensitive drum 1021. The exposure device 1023 exposes the surface of the photosensitive drum 1021 to light based on image data input from the image reading apparatus 1005 or an external apparatus (e.g., a personal computer (PC)), and forms an electrostatic latent image on the surface of the photosensitive drum 1021.

The developing device 1024 stores two-component developer containing toner and carrier, and supplies charged toner to the photosensitive drum 1021 to thereby develop the electrostatic latent image formed on the surface of the photosensitive drum 1021 into a toner image. The toner image formed on the photosensitive drum 1021 is transferred onto the sheet P conveyed by the registration roller pair 1036 by a bias electric field formed by the transfer charging device 1025. The sheet P to which the toner image is transferred is separated from the photosensitive drum 1021 by a bias electric field formed by the separation charging device 1026, and is conveyed toward a fixing unit 1029 by a pre-fixing conveyance unit 1028. Residual toner remaining on the photosensitive drum 1021 without being transferred to the sheet P is removed by the cleaner 1027.

The sheet P conveyed to the fixing unit 1029 is heated while being nipped and pressed by the roller pair. Thus, the toner is melted and fixed onto the sheet P, so that the image is fixed onto the sheet P. In the case of one-sided printing, a discharge roller pair 1010 discharges the sheet P having the image formed on the front surface thereof to a discharge tray 1030 that protrudes to the outside of the printer body 1001A. In the case of two-sided printing, the front surface and the back surface of the sheet P having the image formed on the front surface thereof are reversed by a reversing unit 1039, and the sheet P is conveyed to the registration roller pair 1036 by a two-sided conveyance unit 1040. The image forming unit 1033 forms the toner image on the back surface (second surface) opposite to the front surface (first surface) of the sheet P.

The sheet P having the toner image formed on the back surface thereof is heated and pressed by the fixing unit 1029, so that the image is formed on the back surface of the sheet P. The sheet P having the image formed on both surfaces thereof is discharged to the discharge tray 1030 by the discharge roller pair 1010.

The image forming unit 1033 according to the present exemplary embodiment forms an image on each sheet P by the electrophotographic method. The image forming unit 1033 is an example of an image forming unit. The image forming unit 1033 may form an image on each sheet P by any other method such as an inkjet method or an offset printing method.

Image Reading Apparatus

FIG. 2 is a sectional view of the image reading apparatus 1005. The scanner unit 100 includes a front-surface reading unit 101 (reading unit), a front-surface flow reading glass 106, a white reference member 108, a platen glass 109, a reading movement guide 110, a timing belt 151, and a platen glass motor 169. The image reading apparatus 1005 is configured to execute a document fixed-reading mode for reading an image on a document placed on the platen glass 109 and a document flow reading mode for reading an image on a document conveyed by the ADF 200. In the document fixed-reading mode, the scanner unit 100 drives the platen glass motor 169 to cause the timing belt 151 to move the front-surface reading unit 101 along the reading movement guide 110. The front-surface reading unit 101 reads an image on the front surface of a document placed on the platen glass 109 line by line while moving along the reading movement guide 110, thereby reading the image on the document. The ADF 200 is configured to turn with respect to the scanner unit 100 with a hinge (not illustrated), and functions as a holding portion that holds the document placed on the platen glass 109. In the document flow reading mode, the front-surface reading unit 101 is located at a front-surface reading position 107 and reads the image on the document conveyed by the ADF 200 on the front-surface flow reading glass 106. The front-surface reading unit 101 includes, for example, a contact image sensor (CIS).

The ADF 200 serving as a sheet conveyance apparatus includes a document tray 201 and a pair of side regulation plates 202 (a pair of regulation members). The document tray 201 is a stacking tray on which a document bundle formed of one or more documents is stacked. A document sensor 17 detects a document stacked on the document tray 201. The pair of side regulation plates 202 is provided on the document tray 201 in such a manner that the pair of side regulation plates 202 is movable in a width direction (main-scanning direction) orthogonal to a feed direction CD of the document, and regulates the movement of the document in the width direction.

The ADF 200 further includes a pick roller 210 (conveyance roller) and separation rollers 211. Upon receiving a document conveyance start instruction, the ADF 200 causes the pick roller 210 to descend to an uppermost surface of the document bundle stacked on the document tray 201 and to rotate, thereby conveying an uppermost document in the document bundle. The documents conveyed by the pick roller 210 are separated one by one by the action of the separation rollers 211 as a separation mechanism and are conveyed. The separation of documents by the separation rollers 211 is implemented by a known separation technique. The pick roller 210 and the separation rollers 211 according to the present exemplary embodiment are examples of a feeding unit that separates documents one by one and feeds the documents.

When the document separated by the separation rollers 211 turns on a separation sensor 212, counting of a timer 171 (see FIG. 3) is started. A count value of the timer 171 is used to calculate a double feed detection start timing of a double feed sensor 213 and to calculate the length of each document. A skew detection unit 228 is located downstream of the separation rollers 211, and skew of documents is detected by the skew detection unit 228. The skew detection unit 228 will be described in detail below. When the document reaches near the double feed sensor 213, double feed detection processing by the double feed sensor 213 is started. After that, the document is conveyed to registration rollers 215. A registration sensor 214 detects that the document has reached the registration rollers 215. The leading edge of the document is brought into contact with a nip of the registration rollers 215 in a stopped state and the document is bent in a loop shape, thereby correcting skew of the document. After that, the registration rollers 215 start to rotate and convey the document.

The document passes through a document conveyance path 240, which curves in a U-shape, and is conveyed from the registration rollers 215 to the front-surface flow reading glass 106. The document conveyed through the document conveyance path 240 turns on a read sensor 216, which triggers setting of a first timer value, which is used until the leading edge of the document reaches the front-surface reading position 107, to the timer 171. In the case of double-side simultaneous reading, a second timer value, which is used until the leading edge of the document reaches a back-surface reading position 220, is also set to the timer 171.

After that, first read rollers 217 convey the document to the front-surface reading position 107. The separation rollers 211, the registration rollers 215, the document conveyance path 240, and the first read rollers 217 are covered with an ADF cover 204, which is an exterior member.

When the timer 171 completes counting the first timer value for reading the image on the front surface of the document, reading of the image on the front surface of the document by the front-surface reading unit 101 is started. Specifically, the document conveyed on the front-surface flow reading glass 106 is illuminated by a front-surface light-emitting diode (LED) 102 in the front-surface reading unit 101 from under the front-surface flow reading glass 106. Reflected light from the front surface of the document passes through a front-surface lens array 104 and is read by a front-surface line sensor 103 (CIS). Thus, the image on the front surface of the document is read. The document is conveyed by second read rollers 219 from the front-surface reading position 107 to the back-surface reading position 220 while the image on the front surface of the document is read by the front-surface reading unit 101.

When the timer 171 completes counting the second timer value for reading the image on the back surface of the document, reading of the image on the back surface of the document by a back-surface reading unit 230 (reading unit) is started. In the case of double-side reading, the document conveyed on a back-surface white facing member integrally provided with a back-surface flow reading glass 234 is illuminated by a back-surface LED 231 in the back-surface reading unit 230 from above the back-surface flow reading glass 234. Reflected light from the back surface of the document passes through a back-surface lens array 233 and is read by a back-surface line sensor 232 (CIS). Thus, the image on the back surface of the document is read. The document is conveyed by third read rollers 221 from the back-surface reading position 220 to discharge rollers 223 while the image on the back surface of the document is read by the back-surface reading unit 230. A discharge sensor 222 detects the document that has reached the third read rollers 221. The discharge rollers 223 discharge the document onto a discharge tray 225 through a discharge port 224.

As illustrated in FIG. 2, the front-surface reading unit 101 and the back-surface reading unit 230 respectively include the front-surface line sensor 103 (CIS) and the back-surface line sensor 232 (CIS). Alternatively, the front-surface reading unit 101 and the back-surface reading unit 230 may use a charge-coupled device (CCD) sensor formed of a reduction optical system using a mirror, instead of using a CIS.

Control Configuration

FIG. 3 is a block diagram illustrating the image reading apparatus 1005 and the controller 500. The image reading apparatus 1005 includes the control unit 160, the front-surface LED 102, the front-surface line sensor 103, the back-surface LED 231, the back-surface line sensor 232, the platen glass motor 169, and a document conveyance motor 170. The front-surface LED 102, the front-surface line sensor 103, the back-surface LED 231, the back-surface line sensor 232, the platen glass motor 169, and the document conveyance motor 170 are electrically connected to the control unit 160. The control unit 160 serving as a controller includes a central processing unit (CPU) 164, a read-only memory (ROM) 165, and a random access memory (RAM) 166. The ROM 165 stores control programs for implementing document reading processing. The RAM 166 stores input data and working data. The control unit 160 further includes a lighting control unit 167, a scanning control unit 168, the timer 171, a front-surface image reading control unit 172, a back-surface image reading control unit 173, a conveyance detection unit 174, an analog-to-digital (A/D) conversion unit 161, and an image processing unit 162. The control unit 160 further includes a document main-scanning size obtaining unit 163, a nonvolatile memory 257, and an image processing unit 275.

The lighting control unit 167 controls ON/OFF of illumination of each of the front-surface LED 102 and the back-surface LED 231. The scanning control unit 168 controls driving of the platen glass motor 169. The platen glass motor 169 is connected to the front-surface reading unit 101 via the timing belt 151.

The rotation of the platen glass motor 169 enables the front-surface reading unit 101 to move in a sub-scanning direction SS along the reading movement guide 110. The scanning control unit 168 controls driving of the document conveyance motor 170 incorporated in the ADF 200. The document conveyance motor 170 causes the pick roller 210, the separation rollers 211, the registration rollers 215, the first read rollers 217, the second read rollers 219, the third read rollers 221, and the discharge rollers 223 to rotate to convey the document.

The front-surface line sensor 103 is incorporated in the front-surface reading unit 101. The front-surface line sensor 103 receives light that is applied by the front-surface LED 102 and reflected from the document. The amount of light (analog data) received by the front-surface line sensor 103 is converted into digital data by the A/D conversion unit 161. The image processing unit 162 performs image processing on the digital data received from the A/D conversion unit 161, to thereby generate image data. The back-surface line sensor 232 is incorporated in the back-surface reading unit 230. The back-surface line sensor 232 receives light that is applied by the back-surface LED 231 and reflected from the document. The amount of light (analog data) received by the back-surface line sensor 232 is also converted into image data by the A/D conversion unit 161 and the image processing unit 162.

The document main-scanning size obtaining unit 163 serving as a size information obtaining unit obtains size information input to the CPU 164 from the operation unit 506 provided on the printer body 1001A via the controller 500. The document main-scanning size obtaining unit 163 can also obtain document size information based on a size detection sensor 205 located on the document tray 201.

The image processing unit 275 includes a shading RAM 254 and a shading correction circuit 253. The shading RAM 254 includes an arithmetic memory 255 and a coefficient memory 256. The CPU 164 can access the shading RAM 254 to read out data from the shading RAM 254 or write data into the shading RAM 254.

The nonvolatile memory 257 is a memory (storage unit) configured to hold values (data) even when the image reading apparatus 1005 is powered off. The nonvolatile memory 257 holds, for example, a shading target value used for the shading correction circuit 253 to execute a shading correction, and information indicating an alarm or error that has occurred during a job.

The timer 171 counts pulse signals transmitted from the document conveyance motor 170. The pulse signals are transmitted from the document conveyance motor 170 every time the document is conveyed by a predetermined distance by the document conveyance motor 170. When the number of pulse signals counted by the timer 171 reaches a preset count value, the timer 171 transmits a count complete signal to the CPU 164. The CPU 164 receives the count complete signal from the timer 171, thereby making it possible to measure the distance by which the document is conveyed.

The front-surface image reading control unit 172 controls the front-surface reading unit 101 to execute image reading processing on the front surface of the document. After completion of counting of the first timer value set by the timer 171, the timer 171 outputs a first count complete signal to the CPU 164. Upon receiving the first count complete signal, the CPU 164 transmits a trigger signal to the front-surface image reading control unit 172. Upon receiving the trigger signal, the front-surface image reading control unit 172 starts document image obtaining processing to be performed by the front-surface reading unit 101. The back-surface image reading control unit 173 controls the back-surface reading unit 230 to execute image reading processing on the back surface of the document. After completion of counting of the second timer value set by the timer 171, the timer 171 outputs a second count complete signal to the CPU 164. Upon receiving the second count complete signal, the CPU 164 transmits a trigger signal to the back-surface image reading control unit 173. Upon receiving the trigger signal, the back-surface image reading control unit 173 starts document image obtaining processing to be performed by the back-surface reading unit 230.

The conveyance detection unit 174 obtains ON/OFF states of the separation sensor 212, the skew detection unit 228, the double feed sensor 213, the registration sensor 214, the read sensor 216, and the discharge sensor 222, which are provided along the document conveyance path 240. When the leading edge of the document has reached each sensor and when the trailing edge of the document has passed through each sensor, a signal from each sensor is transmitted to the conveyance detection unit 174. When the CPU 164 receives the signal received by the conveyance detection unit 174 from each sensor as an interrupt, the CPU 164 outputs an instruction signal without delay to the timer 171.

The control unit 160 provided in the image reading apparatus 1005 is electrically connected to the controller 500 provided in the printer body 1001A via a communication line 180. The controller 500 converts image data read by the image reading apparatus 1005 into image data of a format that can be output to the printer 1001 that forms an image on a sheet (recording medium).

The controller 500 converts image data read by the image reading apparatus 1005 into image data of a format that can be output to a PC. The controller 500 also controls the reception of a user operation and the management of the overall operation of the printer 1001. The controller 500 transmits and receives various data signals to and from the control unit 160 of the image reading apparatus 1005 via the communication line 180.

The controller 500 includes a CPU 501, a ROM 502, and a RAM 503. The ROM 502 stores control programs for implementing image conversion, management of the overall operation of the printer 1001, and the like. The RAM 503 stores input data and working data.

The controller 500 further includes an image processing unit 504 and an image memory 505.

The image processing unit 504 converts image data read by the image reading apparatus 1005 into image data of a format that can be output to the printer 1001. The image memory 505 temporarily stores these pieces of image data. The CPU 501 of the controller 500 is electrically connected to the operation unit 506. The operation unit 506 is provided with a display portion and buttons. The CPU 501 receives a button operation by the user from the operation unit 506. The CPU 501 outputs various information for the user to the display portion of the operation unit 506.

In the present exemplary embodiment, the image reading apparatus 1005 includes the CPU 164, the ROM 165, and the RAM 166, and the controller 500 also includes the CPU 501, the ROM 502, and the RAM 503. However, for example, the image reading apparatus 1005 may share the CPU 501, the ROM 502, and the RAM 503 of the controller 500, instead of including the CPU 164, the ROM 165, and the RAM 166. In this case, various components electrically connected to the CPU 164 illustrated in FIG. 3 may be directly connected to the CPU 501 of the controller 500 without using the communication line 180. The present exemplary embodiment illustrates a configuration in which the image reading apparatus 1005 and the controller 500 include the CPU 164 and the CPU 501, respectively. A configuration in which the CPU 164 is omitted and the CPU 501 is shared by the image reading apparatus 1005 can be achieved by replacing the CPU 164 with the CPU 501, as needed.

Staple Detection

As described above, the ADF 200 separates documents one by one by the action of the separation rollers 211 and conveys the documents. Accordingly, the ADF 200 cannot separate and feed “bound documents” such as documents bound with a staple or pasted documents. If such documents are accidentally placed on the document tray 201, the documents may be damaged due to the separation operation performed by the separation rollers 211. Therefore, in the present exemplary embodiment, the skew detection unit 228 provided on the ADF 200 detects skew of documents, and the feed operation is cancelled when skew of documents is detected, to thereby prevent the documents from being damaged. The term “staple” used in the present exemplary embodiment refers to, for example, a deformable U-shaped staple that penetrates through a plurality of documents.

FIG. 5 is a side view and a top view illustrating the vicinity of the separation rollers 211 when bound documents DS are fed. The bound documents DS are a bundle of documents bound with a staple at a staple portion ST that corresponds to a front-side end portion at the leading edge of the document. The skew detection unit 228 includes a first sensor 228a and a second sensor 228b. The first sensor 228a and the second sensor 228b are photosensors that are located downstream of the separation rollers 211 in the feed direction CD and upstream of the registration rollers 215 and are each configured to detect the leading edge of the document. The first sensor 228a and the second sensor 228b are located side by side in the width direction at an interval W. Specifically, the first sensor 228a and the second sensor 228b are located at the same position in the feed direction CD and are located at different positions in the width direction. More specifically, the first sensor 228a and the second sensor 228b are located symmetrically about the center (conveyance center) in the width direction of the conveyance path of the ADF 200. In this case, however, the first sensor 228a and the second sensor 228b need not necessarily be located symmetrically about the conveyance center, and may be located at deviated positions in the feed direction CD.

If documents are normally conveyed (without being screwed), the first sensor 228a and the second sensor 228b located in this manner can detect the leading edge of each document almost at the same time. However, if the bound documents DS are conveyed, the uppermost document cannot be separated, so that the uppermost document is rotated (skewed) around the staple portion ST at a separation nip of the separation rollers 211. In this case, as illustrated in FIG. 5, the second sensor 228b detects the leading edge of the document earlier than the first sensor 228a. Accordingly, in a case where the first sensor 228a does not detect the document before a predetermined time period elapses since the document is detected by the second sensor 228b, the CPU 164 determines that there is a possibility that the fed documents may be bound documents. If the staple portion ST of the bound documents DS is located at a back-side end portion, the first sensor 228a detects the leading edge of the document earlier than the second sensor 228b. Also, in this case, if the second sensor 228b does not detect the document before a predetermined time period elapses since the document is detected by the first sensor 228a, the CPU 164 determines that there is a possibility that the fed documents may be bound documents. In other words, if one of the first sensor 228a and the second sensor 228b does not detect the document before the predetermined time period has elapsed after the other of the first sensor 228a and the second sensor 228b has detected the document, the CPU 164 determines that the fed documents are bound documents and executes stopping processing to stop the feed operation. Thus, based on the difference in the detection timing between the first sensor 228a and the second sensor 228b, the CPU 164 can determine whether skew of documents has occurred (whether the documents are bound documents).

The predetermined time period for the skew detection unit 228 based on which the CPU 164 determines to stop the document feed operation can be arbitrarily set. In the present exemplary embodiment, the difference in the detection timing between the first sensor 228a and the second sensor 228b that occurs when the leading edge of a document is inclined at 3° with respect to the width direction is set as the predetermined time period. To detect skew of documents, the interval W between the first sensor 228a and the second sensor 228b may be desirably large. This is because the difference in the detection timing between the first sensor 228a and the second sensor 228b becomes prominent when the interval W is large, which makes it possible to accurately detect skew of documents. On the other hand, if the interval W is extremely large, it may be difficult to detect a document with a smaller size. Therefore, in the present exemplary embodiment, the first sensor 228a and the second sensor 228b are respectively located at positions near both ends in the width direction of a minimum-size document that can be conveyed by the ADF 200.

Different-Width Mixed Stacking Mode

FIG. 4A is a top view of the ADF 200 in a state where only documents D1 with the same size are set on the document tray 201. FIG. 4B is a top view of the ADF 200 in a state where the document D1 and a small-size document D2 are set on the document tray 201.

The pair of side regulation plates 202 includes a back-side regulation plate 202a located on the back side and a front-side regulation plate 202b located on the front side. As illustrated in FIG. 4A, the back-side regulation plate 202a contacts the back-side edge of the document D1, and the front-side regulation plate 202b contacts the front-side edge of the document D1. The back-side regulation plate 202a and the front-side regulation plate 202b are configured to be movable in the width direction in conjunction with each other by an interlocking mechanism (not illustrated). For example, if the user has moved the front-side regulation plate 202b to the back side, the back-side regulation plate 202a is moved to the front side in conjunction with the movement of the front-side regulation plate 202b.

As illustrated in FIG. 4A, if all documents D1 in a document bundle set on the document tray 201 have the same size, all the documents D1 contact both the back-side regulation plate 202a and the front-side regulation plate 202b. In this case, the center in the width direction of each document D1 substantially matches the conveyance center of the ADF 200. This regulates the movement of each document in the width direction and prevents skew of each document during the feed operation. In the present exemplary embodiment, a mode for feeding a plurality of documents with the same size is referred to as a normal mode or a non-mixed stacking mode. Also, in the case of reading a plurality of documents with the same width and different lengths, all the documents contact both the back-side regulation plate 202a and the front-side regulation plate 202b. Thus, a mode for feeding a plurality of documents with the same width and different lengths is referred to as a same-width mixed stacking mode.

In some cases, a document bundle may include a plurality of documents with different widths (large-size document D1 and small-size document D2 in FIG. 4B). A mode for feeding a plurality of documents with different widths is referred to as a different-width mixed stacking mode. In the different-width mixed stacking mode, the back-side regulation plate 202a and the front-side regulation plate 202b are moved to accommodate the document D1 with a larger width. In this case, the both edges in the width direction of the document D2 with a smaller width cannot be regulated by both the back-side regulation plate 202a and the front-side regulation plate 202b. Therefore, in the different-width mixed stacking mode, the document D2 with a smaller width is placed on the document tray 201 in such a manner that only the back-side edge of the document D2 contacts the back-side regulation plate 202a. In this case, the front-side edge of the document D2 with a smaller width does not contact the front-side regulation plate 202b. In other words, in the different-width mixed stacking mode, smaller documents are set on the document tray 201 in a state where the documents are aligned on the back side. When the user selects the different-width mixed stacking mode, the operation unit 506 displays a message for prompting the user to set smaller documents in a state where the documents are aligned on the back side (see FIG. 8C).

FIGS. 8A to 8C each illustrate an example of a screen to be displayed on the operation unit 506. FIG. 8A illustrates an example of a standby screen to be displayed in a copy mode. FIG. 8B illustrates an example of a setting screen for “other functions”. FIG. 8C illustrates an example of a setting screen for “mixed document stacking”. For example, when the user sets the different-width mixed stacking mode in the copy mode, the user presses an “other functions” key 604 illustrated in FIG. 8A, which is the copy mode standby screen, on the operation unit 506 to display the screen illustrated in FIG. 8B. After that, the user presses a “mixed document stacking” key 605 on the screen illustrated in FIG. 8B to display a screen illustrated in FIG. 8C. The screen illustrated in FIG. 8C is a screen for the user to set the different-width mixed stacking mode. In this case, the user designates a mode depending on the size of a document bundle placed on the document tray 201. In this case, if documents with different widths at stacked, the user presses a “different widths” button 606, and if documents with the same width are stacked, the user presses a “same width” button 607. When the user presses the “different widths” button 606 and then presses an “OK” button 608, the different-width mixed stacking mode is set and mode information is stored in the RAM 503.

After that, the screen of the operation unit 506 returns to the screen illustrated in FIG. 8B. Accordingly, the user presses a “close” button 609 to return to the copy mode standby screen illustrated in FIG. 8A. When the user presses a “start” button 610 after making other settings, information stored in the RAM 503 is transmitted to the CPU 164 via the communication line 180 and the image reading apparatus 1005 starts the document feed operation in the different-width mixed stacking mode.

Control in Different-Width Mixed Stacking Mode

In the different-width mixed stacking mode, the control unit 160 according to the present exemplary embodiment executes conveyance control processing different from that in the normal mode. FIG. 6 illustrates a relationship between documents and the skew detection unit 228 during different-width mixed stacking. FIG. 6 illustrates an example where the large-size document D1 and the small-size document D2 are stacked in a mixed manner as illustrated in FIG. 4B. As described above, in the different-width mixed stacking mode, the small-size document D2 is set at a position deviated from the conveyance center. Further, as described above, the first sensor 228a and the second sensor 228b of the skew detection unit 228 are located side by side in the width direction.

Accordingly, in the different-width mixed stacking mode, in the case of feeding the small-size document D2, the small-size document D2 may pass through only the first sensor 228a without passing through the second sensor 228b. In this case, the second sensor 228b does not detect the document D2 before the predetermined time period elapses after the first sensor 228a has detected the document D2, so that the CPU 164 erroneously determines that skew has occurred (bound documents are fed). Therefore, according to the present exemplary embodiment, in the different-width mixed stacking mode, the control unit 160 disables skew detection (staple detection) by the skew detection unit 228. In this case, the control unit 160 may skip the document detection processing performed by the first sensor 228a and the second sensor 228b, or may disregard detection results from the first sensor 228a and the second sensor 228b. In any case, in the different-width mixed stacking mode, the control unit 160 does not execute feed stopping processing based on both the first sensor 228a and the second sensor 228b. On the other hand, in the normal mode or the same-width mixed stacking mode, the control unit 160 executes skew detection processing by the skew detection unit 228.

FIG. 10A illustrates an image region area A and positions of documents when the distance between documents is small. FIG. 10B illustrates the image region area A and positions of documents when the distance between documents is large. In the different-width mixed stacking mode, the small-size document D2 is set at a position deviated from the conveyance center, so that the pick roller 210 and the separation rollers 211 contact a front side relative to the center of the small-size document D2. Accordingly, in the different-width mixed stacking mode, skew of documents is more likely to occur than in the normal mode. If the skew is large, for example, in a case where the control unit 160 performs processing for determining the leading edge of a document based on an image within a predetermined area (image region area A), both the trailing edge of a preceding document and the leading edge of a subsequent document may appear in the same image region area A as illustrated in FIG. 10A. Thus, in the different-width mixed stacking mode, the risk of erroneous detection is higher than that in the normal mode in processing for detecting a leading edge position, a document angle, or the like based on image data. Therefore, in the different-width mixed stacking mode, the control unit 160 controls the conveyance in such a manner that the distance between the trailing edge of the preceding document and the leading edge of the subsequent document (interval between sheets) is larger than the distance in the normal mode. This control operation allows a single document to fall within a single image region area A as illustrated in FIG. 10B, so that stable reading can be achieved.

FIG. 11A is an explanatory diagram illustrating white filling processing when an earlier white filling start timing is set.

FIG. 11B is an explanatory diagram illustrating white filling processing when a later white filling start timing is set. The control unit 160 includes a function for performing white filling processing on the outside of a document region. In this case, if white filling processing is started at a document trailing edge detection timing as illustrated in FIG. 11A, a part of the skewed document may be filled with white, which may cause an image defect. Therefore, in the different-width mixed stacking mode, the white filling processing is started at a later timing than in the normal mode as illustrated in FIG. 11B, thereby making it possible to reduce the risk of occurrence of an image detect.

If the different-width mixed stacking mode is not designated (i.e., in the normal mode), the sheet P to be printed is determined based on the size of the document detected on the document tray 201, regardless of the read document size. In this case, if documents with different widths are stacked, the largest document in the document bundle is detected on the document tray 201, and the sheet P to be printed is determined based on the size of the detected document. For example, if two types of documents, i.e., an A4-size document and a B5-size document, are fed in a job in the copy mode, the both types of documents are output as the A4-size document. Accordingly, in the present exemplary embodiment, the control unit 160 executes printing on an appropriate sheet P for each document based on the read document size in the different-width mixed stacking mode. This makes it possible to print out a copy of an A4-size document on an A4-size sheet and to print out a copy of a B5-size document on a B5-size sheet.

As described above, in the different-width mixed stacking mode, the control unit 160 executes conveyance control processing different from that in the normal mode. Accordingly, it may be desirable for the user to set the normal mode to read a bundle of documents with the same size and to set the different-width mixed stacking mode to read documents with different sizes. However, in the different-width mixed stacking mode, the type of a sheet to be output by the printer body 100A can be determined only after the document size is determined. Therefore, a job can be carried out with higher productivity in the normal mode in which the sheets P with the same size are continuously output. For this reason, it may be desirable to set the normal mode (different-width mixed stacking mode is not set) in default settings, and it may be desirable for the user to perform the operation of reading documents with different widths in the different-width mixed stacking mode.

Display Contents during Skew Detection

FIG. 7 illustrates an example of a predetermined screen to be displayed on the operation unit 506 in a case where skew of documents is detected by the skew detection unit 228. The screen illustrated in FIG. 7 is displayed on the operation unit 506 at the time when skew of documents is detected and feed processing is cancelled. The timing of displaying the screen illustrated in FIG. 7 is not limited to this timing. For example, the screen may be displayed after the user has removed documents stuck in the ADF 200. On the screen illustrated in FIG. 7, a button 601 for temporarily turning off the skew detection sensors and a button 602 for turning on the different-width mixed document stacking (different-width mixed stacking mode) are displayed. In this case, if the actually fed documents are bound documents, the user presses a cancel button 603 to cancel the job. Then, the user removes the documents that include stuck bound documents and remain in the conveyance path of the ADF 200. After that, the user excludes the bound documents, or removes staples or the like, and then places the document bundle on the document tray 201 again and resets the job.

If the actually fed documents are not bound documents and have the same size, there is a possibility that the documents may be obliquely placed on the document tray 201 (rough setting), or documents are more likely to be skewed due to crease, twisting, or the like. In the case of rough setting, it may be sufficient for the user to place the bundle of aligned documents on the document tray 201 again. However, if the documents are more likely to be skewed, there is a possibility that the skew detection unit 228 may determine that the documents are skewed again after the documents are conveyed again and the conveyance may be interrupted. For this reason, the user presses the button 601 for temporarily turning off the skew detection sensors. When the button 601 is pressed, information indicating that the button 601 is pressed is stored in the RAM 503. If the document conveyance operation is restarted in this state, the information stored in the RAM 503 is transmitted to the CPU 164 via the communication line 180 and skew detection by the skew detection unit 228 is disabled. In other words, the button 601 is an example of a second setting portion for disabling skew detection by the skew detection unit 228 without setting the different-width mixed stacking mode (still in the normal mode) for a suspended job when the job is restarted. This makes it possible to perform document bundle reading processing while preventing a job from being interrupted even in a state where documents are more likely to be skewed.

Next, a case where documents with different widths are actually fed but the user has not set the different-width mixed stacking mode will be described. Examples of the case where the user has not set the different-width mixed stacking mode may include a case where the user does not know the presence of the different-width mixed stacking mode, a case where the user knows the different-width mixed stacking mode but has forgotten to set the different-width mixed stacking mode, and a case where a document bundle happened to include a document with a size different from the other documents. In such cases, the user presses the button 602 for turning on the different-width mixed document stacking. When the button 602 is pressed, information similar to that when the “different widths” button 606 illustrated in FIG. 8C is pressed is stored in the RAM 503. In other words, the button 602 is an example of a first setting portion for setting the different-width mixed stacking mode for a suspended job when the job is restarted. If the document conveyance operation is restarted in this state, the information stored in the RAM 503 is transmitted to the CPU 164 via the communication line 180 and the feed operation in the different-width mixed stacking mode is executed. As described above, in the different-width mixed stacking mode, the CPU 164 disables skew detection by the skew detection unit 228, thereby making it possible to perform the document bundle reading operation while preventing a job from being interrupted.

Any message other than the message illustrated in FIG. 7 may be displayed on the button 602 for turning on the different-width mixed document stacking. For example, a message “documents with different widths are stacked” may be displayed to prompt the user to approve setting of the different-width mixed stacking mode, or an icon such as an icon displayed above the “different widths” button 606 illustrated in FIG. 8C may be displayed for the user to visually recognize the state.

Description of Flowcharts

FIGS. 9A and 9B are flowcharts each illustrating processing to be performed when the document feed operation is interrupted. The processing illustrated in FIG. 9A is implemented such that the CPU 164 executes programs stored in the ROM 165. The processing illustrated in FIG. 9B is implemented such that the CPU 501 executes programs stored in the RAM 503.

First, when an image reading job is started, in step S1100 illustrated in FIG. 9B, the CPU 501 issues a conveyance start command to the image reading apparatus 1005. When the document feed operation by the ADF 200 is started, in step S1001 illustrated in FIG. 9A, the CPU 164 determines whether a staple detection OFF instruction or a different-width mixed stacking mode designation ON instruction is issued. If one of the instruction is issued (YES in step S1001), the processing proceeds to step S1008. If neither of the instructions is issued (NO in step S1001), the processing proceeds to step S1002. In step S1002, skew detection is performed by the skew detection unit 228. Next, in step S1003, the CPU 164 compares skew detection results. If the amount of skew of documents is less than a predetermined value (NO in step S1003), the CPU 164 determines that documents are normally fed, and then the processing proceeds to step S1008.

If the amount of skew of documents is more than or equal to the predetermined value (YES in step S1003), the processing proceeds to step S1004. In step S1004, the CPU 164 causes the document conveyance motor 170 of the ADF 200 to stop to stop the document feed operation and transmits information indicating abnormal stop to the CPU 501. Then, the processing proceeds to step S1005 and the CPU 164 waits for the next command from the CPU 501. In step S1101 illustrated in FIG. 9B, the CPU 501 determines whether information indicating abnormal stop is transmitted. If information indicating abnormal stop is not transmitted (NO in step S1101), the processing proceeds to step S1109. If information indicating abnormal stop is transmitted (YES in step S1101), the processing proceeds to step S1102. In step S1102, the CPU 501 causes the operation unit 506 to display the screen illustrated in FIG. 7 to prompt the user to issue the next instruction. Then, the processing proceeds to step S1103. In step S1103, the CPU 501 determines whether any one of the buttons 601 to 603 illustrated in FIG. 7 is pressed. If any one of the buttons 601 to 603 is pressed (YES in step S1103), the processing proceeds to step S1104. In step S1104, the CPU 501 determines which button is pressed. If the cancel button 603 is pressed, the processing in this flowchart ends. If the button 601 for turning off the skew detection sensors is pressed, the processing proceeds to step S1105. In step S1105, information indicating that the button 601 is pressed is stored in the RAM 503, and then the processing proceeds to step S1106. If the button 602 for turning on the different-width mixed stacking mode is pressed in step S1104, the processing proceeds to step S1205. In step S1205, information indicating that the button 602 is pressed is stored in the RAM 503, and then the processing proceeds to step S1106.

In step S1106, the CPU 501 waits for an operation to be subsequently executed from the user.

If an instruction is issued from the user (YES in step S1106), the processing proceeds to step S1107. In step S1107, the CPU 501 determines whether a conveyance restart instruction is issued from the user. If the conveyance restart instruction is not issued from the user (NO in step S1107), the processing in this flowchart ends. If the conveyance restart instruction is issued from the user (YES in step S1107), the processing proceeds to step S1108. In step S1108, the CPU 501 transmits information stored in the RAM 503 in step S1105 or step S1205 and a document conveyance start command to the CPU 164 via the communication line 180. Then, when it is determined that an implementation content instruction is issued in step S1005 illustrated in FIG. 9A, the processing proceeds to step S1006. In step S1006, the CPU 164 determines whether the conveyance restart instruction is issued from the user. If the conveyance restart instruction is not issued from the user (NO in step S1106), the processing in the flowchart illustrated in FIG. 9A ends. If the conveyance restart instruction is issued from the user (YES in step S1006), the processing proceeds to step S1007. In step S1007, the CPU 164 starts the document conveyance operation in the mode instructed by the CPU 501. In this case, the user performs so-called jam processing, as needed, such as processing of resetting the documents being conveyed on the document tray 201 in advance. In step S1008, the CPU 164 determines whether there is any document placed on the document tray 201, i.e., if the last document to be conveyed has already been conveyed. If there are documents placed on the document tray 201, i.e., the last document to be conveyed has not been conveyed yet, (NO in step S1008), the processing returns to step S1001. If all documents are fed and there are no documents placed on the document tray 201, i.e., the last document to be conveyed has been conveyed (YES in step $1008), the processing proceeds to step S1009. In step S1009, the CPU 164 transmits image reading end information, and then the processing in the flowchart illustrated in FIG. 9A ends. In step S1109 illustrated in FIG. 9B, the CPU 501 determines whether the image reading end information is transmitted from the image reading apparatus 1005. If the image reading end information is not transmitted, the processing returns to step S1101. In step S1101, the CPU 501 continuously monitors abnormal document conveyance until the document conveyance operation ends. If the image reading end information is transmitted (YES in step S1109), the processing in the flowchart illustrated in FIG. 9B ends.

As described above, in the present exemplary embodiment, if skew of documents is detected and the feed operation is stopped, the operation unit 506 displays the predetermined screen including the button 602 for setting the different-width mixed stacking mode. This makes it possible to restart the document feed operation in an appropriate mode, for example, even when the user has forgotten to set the different-width mixed stacking mode, or the user does not know the presence of the different-width mixed stacking mode. Further, it is possible to simplify the operation for setting the different-width mixed stacking mode after the feed operation is stopped.

Furthermore, in the present exemplary embodiment, if skew of documents is detected and the feed operation is stopped, the operation unit 506 displays the predetermined screen including the button 601 for disabling skew detection by the skew detection unit 228 instead of setting the different-width mixed stacking mode. This makes it possible to restart the document feed operation in an appropriate state even in a state where documents are more likely to be skewed due to crease, twisting, or the like. When the button 601 is pressed, the different-width mixed stacking mode is not set and the normal mode is maintained, so that a job can be restarted without deteriorating the productivity.

The button 602 for turning on the different-width mixed document stacking need not necessarily be displayed on the operation unit 506 when the document feed operation is stopped. For example, if the document feed operation is stopped in a job in a state where the same-width mixed stacking mode or the different-width mixed stacking mode is already set, the button 602 for turning on the different-width mixed document stacking may be hidden as illustrated in FIG. 12A. Further, in a state where the same-width mixed stacking mode or the different-width mixed stacking mode is already set, the button 602 for turning on the different-width mixed document stacking may be grayed out as illustrated in FIG. 12B to prevent the user from selecting the button 602. This prevents the user from performing an unwanted operation, which leads to an improvement in operability.

According to the present disclosure, it is possible to provide an image reading apparatus and an image forming apparatus that facilitate setting of the different-width mixed stacking mode after skew of documents (bound documents) is detected, thereby improving the operability.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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 priority from Japanese Patent Application No. 2023-202124, filed Nov. 29, 2023, which is hereby incorporated by reference herein in its entirety.

SHEET CONVEYANCE APPARATUS, IMAGE READING APPARATUS, AND IMAGE FORMING APPARATUS

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