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

Abstract

A sheet conveyance apparatus includes a stacking portion, a feeding portion, first and second detection units, a controller, and a setting unit. The feeding portion separates and feeds sheets stacked on the stacking portion. Of a sheet fed by the feeding portion, the first detection unit detects skewing, and the second detection unit detects flip-up. The controller stops feeding where skewing of the sheet is detected by the first detection unit and where flip-up of the sheet is detected by the second detection unit. The setting unit sets a different-width mixed document mode in which a plurality of sheets having different widths is stacked on the stacking portion. In a case where the different-width mixed document mode is set by the setting unit, the controller does not stop feeding based on skewing detected by the first detection unit but stops feeding based on flip-up detected by the second detection unit.

Description

BACKGROUND

Field

The present disclosure relates to a sheet conveyance apparatus for conveying sheets, an image reading apparatus for reading image information from sheets, and an image forming apparatus for forming images on recording materials.

Description of the Related Art

Conventionally, image reading apparatuses for reading images on documents while conveying the documents using auto document feeders (ADFs), mounted on copying machines, facsimile apparatuses, and digital multifunction peripherals, have been known. Such an ADF separates and feeds documents stacked on a document tray one by one. Therefore, the ADF cannot separate and feed stapled documents (so-called “bound documents”), so that the documents may be damaged if the bound documents are fed by error.

Japanese Patent Application Laid-Open No. 2021-017298 discusses a sheet conveyance apparatus which detects bound documents through a flip-up detection unit for detecting flip-up of a document and a skewing detection unit for detecting skewing of a document.

This sheet conveyance apparatus can prevent documents from being damaged by stopping feeding of documents when bound documents are detected. The flip-up detection unit includes a sensor mounted above a document tray, and the skewing detection unit includes a plurality of sensors arranged side by side in a width direction.

A pair of regulation plates for regulating the positions of the set documents in the width direction is arranged on the document tray. In a case where documents having different widths (so-called “different-width mixed documents”) are set on the document tray, a document having a smaller width is set to abut on one of the regulation plates. Therefore, a document having a smaller width is placed at a position shifted from a conveyance center, and this may cause the skewing detection unit to erroneously detect occurrence of skewing.

SUMMARY

The present disclosure is directed to a sheet conveyance apparatus, an image reading apparatus, and an image forming apparatus, capable of detecting bound documents even in a case where mixed documents having different widths are processed.

According to an aspect of the present disclosure, a sheet conveyance apparatus includes a stacking portion on which sheets are to be stacked, a feeding portion configured to separate and feed the sheets stacked on the stacking portion one by one, a first detection unit configured to detect skewing of the sheet fed by the feeding portion, a second detection unit configured to detect flip-up of the sheet fed by the feeding portion, a controller configured to stop feeding executed by the feeding portion in a case where skewing of the sheet is detected by the first detection unit and in a case where flip-up of the sheet is detected by the second detection unit, and a setting unit configured to set a different-width mixed document mode in which a plurality of sheets having different widths is stacked on the stacking portion, wherein, in a case where the different-width mixed document mode is set by the setting unit, the controller does not stop feeding based on skewing detected by the first detection unit but stops feeding based on flip-up detected by the second detection unit.

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 cross-sectional diagram of a printer.

FIG. 2 is a control block diagram of the printer.

FIG. 3A is a diagram illustrating an example of a screen for performing a copy setting. FIG. 3B is a diagram illustrating an example of a screen for performing a stacking mode setting.

FIG. 4 is a top plan diagram illustrating a position of a skewing detection sensor.

FIG. 5 is a perspective diagram illustrating a position of a flip-up detection sensor.

FIG. 6 is a flowchart illustrating a document feeding operation.

FIG. 7 is a flowchart illustrating flip-up detection processing.

FIG. 8A is a perspective diagram illustrating a state where bound documents are stacked. FIG. 8B is a perspective diagram illustrating a state where the bound documents are fed. FIG. 8C is a perspective diagram illustrating a state where flip-up occurs in the bound documents.

FIG. 9A is a perspective diagram illustrating a state where normal documents are conveyed. FIG. 9B is a perspective diagram illustrating a state where a conveyed normal document has passed a second skewing detection sensor.

FIG. 10A is a perspective diagram illustrating a state where bound documents are stacked. FIG. 10B is a perspective diagram illustrating a state where the bound documents are fed. FIG. 10C is a perspective diagram illustrating a state where flip-up occurs in the bound documents.

FIG. 11 is a flowchart illustrating skewing detection processing.

FIG. 12A is a top plan diagram illustrating a state where bound documents are stacked. FIG. 12B is a top plan diagram illustrating a state where the bound documents are fed and skewing has occurred.

FIG. 13A is a top plan diagram illustrating a state where mixed documents having different widths are stacked. FIG. 13B is a top plan diagram illustrating a state where the mixed documents having different widths are fed.

FIG. 14 is a diagram illustrating an example of a screen for performing a bound documents detection setting.

FIG. 15 is a perspective diagram of an image reading apparatus.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a first exemplary embodiment of the present disclosure will be described with reference to the appended drawings. The below-described exemplary embodiment is an example embodying the present disclosure, and is not intended to limit a technical range of the present disclosure.

[Image Forming Apparatus]

First, an image forming apparatus according to a first exemplary embodiment will be described. FIG. 1 is a schematic cross-sectional diagram of a printer 100 described as the image forming apparatus according to the present exemplary embodiment. The printer 100 is an electrophotographic laser beam printer. The printer 100 includes a printer main body 70 and an image reading apparatus 10 mounted on the upper part of the printer main body 70. The printer 100 further includes an operation unit 506 for accepting an operation performed by the user. A display panel 506a serving as a display portion for displaying information to the user is arranged on the operation unit 506.

The display panel 506a is a touch panel the user can operate by touching the display panel 506a with a finger.

Hereinafter, one side of the printer 100 where the operation unit 506 is arranged is called a front side, and another side thereof opposite to the one side is called a rear side. Accordingly, FIG. 1 is a diagram viewed from the front side of the printer 100. In the present exemplary embodiment, sheets include special paper such as coated paper, recording materials having special shapes such as envelopes and index paper, plastic films used for overhead projectors, and fabrics, in addition to normal paper, and documents are also examples of the sheets.

The printer main body 70 includes an image forming engine 60. The image forming engine 60 includes an image forming unit PU serving as an electrophotographic image forming unit and a fixing device 7. When the printer 100 is instructed to start executing an image forming operation, a photosensitive drum 1 serving as a photosensitive body is rotated, and a surface of the photosensitive drum 1 is uniformly charged by a charging device 2. Then, an exposure device 3 modulates and outputs laser light based on image data transmitted from the image reading apparatus 10 or an external computer, and scans the surface of the photosensitive drum 1 with laser light to form an electrostatic latent image. This electrostatic latent image is visualized (developed) to a toner image with toner supplied from a development device 4.

A feeding operation is executed concurrent with the above-described image forming operation, so that a recording material S stacked on a cassette 9 or a manual sheet feeding tray (not illustrated) is fed to the image forming engine 60. The fed recording material S is conveyed in tandem with the progress of the image forming operation executed by the image forming unit PU. Then, the toner image borne on the photosensitive drum 1 is transferred to the recording material S by a transfer roller 5. Toner remaining in the photosensitive drum 1 after transfer of the toner image is collected by a cleaning device 6. The recording material S to which the unfixed toner image has been transferred is forwarded to the fixing device 7, and heated and pressurized while being pinched by a roller pair. The recording material S on which the toner image has been fixed is discharged to a discharge tray 71.

[Image Reading Apparatus]

Next, the image reading apparatus 10 will be described. As illustrated in FIG. 1, the image reading apparatus 10 includes an auto document feeder (ADF) 20 serving as a sheet conveyance apparatus for conveying documents D and a reading unit 40 serving as a reading unit for reading a document D conveyed by the ADF 20. The ADF 20 is supported by a hinge (not illustrated), so that the ADF 20 can turn with respect to the reading unit 40 to uncover a document positioning glass table 41. In addition, the documents D as one example of the sheets can be blank sheets or sheets with images formed on one side or two sides thereof.

The ADF 20 includes a document tray 21 serving as a stacking portion for stacking the documents D and a discharge tray 32 for discharging the documents D. A first regulation plate 21a and a second regulation plate 21b serving as regulation plates for regulating positions in a width direction of the documents D set on the document tray 21 are mounted on the document tray 21. The first regulation plate 21a is arranged on a front side, and abuts on the front side edges of the documents D stacked on the document tray 21. The second regulation plate 21b is arranged on a rear side, and abuts on the rear side edges of the documents D stacked on the document tray 21. The first regulation plate 21a and the second regulation plate 21b as a pair of regulation plates are interlocked and moved in the width direction by an interlocking mechanism (not illustrated). Specifically, in a case where one of the first regulation plate 21a and the second regulation plate 21b is moved in one direction parallel to the width direction, another one of the first regulation plate 21a and the second regulation plate 21b is moved in a direction opposite to the one direction. Then, each of the first regulation plate 21a and the second regulation plate 21b abuts on the edges of the documents D in the width direction to regulate the positions of the documents D. The width direction is a direction orthogonal to a sheet conveyance direction (feeding direction) the ADF 20 conveys the documents D.

The ADF 20 includes a pickup roller 22, a feeding roller 23, a separation roller 24, a conveyance roller pair 25, a read roller pair 26, a read roller pair 30, and a discharge roller pair 31. The pickup roller 22, the feeding roller 23, and the separation roller 24 are examples of feeding portions according to the present exemplary embodiment. The ADF 20 further includes a document presence/absence sensor S31 for detecting presence or absence of the document D stacked on the document tray 21 and a first skewing detection sensor S11 and a second skewing detection sensor S12 serving as a first detection unit for detecting skewing of the document D. The first skewing detection sensor S11 is an example of a first sensor, and the second skewing detection sensor S12 is an example of a second sensor. Further, the ADF 20 includes a light emitting portion S21 and a light receiving portion S22 serving as a second detection unit for detecting flip-up of the document D. Flip-up of the document refers to a state where a fed document is turned up and deformed by external force. The light receiving portion S22 is a sensor for receiving light emitted from the light emitting portion S21. The light emitting portion S21 and the light receiving portion S22 constitute a flip-up detection sensor for detecting flip-up of a document. The light emitting portion S21 and the light receiving portion S22 are examples of third sensors.

The reading unit 40 includes a feeding-reading glass 28, a jump stand 29, a reference white plate 42, a document positioning glass table 41, a first mirror rack 43, a second mirror rack 44, lenses 45, and a charge coupled device (CCD) line sensor 46. A lamp 47 and a mirror 48 are arranged inside the first mirror rack 43. Mirrors 49 and 50 are arranged inside the second mirror rack 44. The first mirror rack 43 and the second mirror rack 44 can be moved in a sub-scanning direction (right-left direction in FIG. 1) by a wire and a driving motor which are not illustrated.

The image reading apparatus 10 can execute a feeding-reading mode and a fixed reading mode. In the feeding-reading mode, images of the documents D are read while the documents D stacked on the document tray 21 are being fed by the ADF 20. In the fixed reading mode, an image of the document D placed on the document positioning glass table 41 is read. The feeding-reading mode is selected in a case where the document presence/absence sensor S31 detects the documents D stacked on the document tray 21 or the user explicitly instructs execution of the feeding-reading mode via the operation unit 506.

When the feeding-reading mode is executed, the pickup roller 22 supported by an arm (not illustrated) is moved down, and abuts on the uppermost document D stacked on the document tray 21. Then, the documents D are fed by the pickup roller 22 and separated one by one at a separation nip formed by the feeding roller 23 and the separation roller 24. The feeding roller 23 is formed of a material such as rubber having the friction lower than that of the separation roller 24. A torque limiter is arranged in a power transmission path for transmitting power to the separation roller 24, so that the separation roller 24 is rotated together with the feeding roller 23 when only one document D is fed thereto, and is not rotated when fed documents D are two or more. With this configuration, the feeding roller 23 and the separation roller 24 can separate the documents D one by one. In addition, the separation roller 24 can be a separation member such as a separation pad having a friction member. Further, the feeding roller 23 can be a rotation member such as a belt arranged in a rotatable state.

The documents D fed from the document tray 21 are conveyed by the conveyance roller pair 25, and further conveyed to the feeding-reading glass 28 by the read roller pair 26. A platen guide roller 27 is arranged at a position facing the feeding-reading glass 28. The platen guide roller 27 guides the document D passing through the feeding-reading glass 28 to prevent the document D from floating up from the feeding-reading glass 28.

Then, an image formed on a surface of the document D is read by the reading unit 40 via the feeding-reading glass 28. Specifically, the conveyed document D is irradiated with light emitted from the lamp 47, and the light reflected from the document D is guided to the lenses 45 by the mirrors 48, 49, and 50. Then, the light that has passed through the lenses 45 forms an image on a light receiving portion of the CCD line sensor 46, and the image is converted photoelectrically, so that the image information is transmitted to a central processing unit (CPU) 81. The reference white plate 42 is used as a reference for the reading luminance of the document D. The document D that has passed through the feeding-reading glass 28 is guided to the read roller pair 30 by the jump stand 29, and discharged to the discharge tray 32 by the discharge roller pair 31.

On the other hand, the fixed reading mode is selected in a case where the reading unit 40 detects a document D placed on the document positioning glass table 41 or the user explicitly instructs execution of the fixed reading mode through the operation unit 506. In the fixed reading mode, the first mirror rack 43 and the second mirror rack 44 are moved along the document positioning glass table 41, and the document D is scanned with light emitted from the lamp 47. The image information photoelectrically converted by the light receiving element of the CCD line sensor 46 is transmitted to the CPU 81.

[Control Block]

FIG. 2 is a control block diagram of the CPU 81 as a controller. The first skewing detection sensor S11, the second skewing detection sensor S12, the light emitting portion S21, the light receiving portion S22, and the document presence/absence sensor S31 are connected to the CPU 81. Further, a feeding motor 84 and a conveyance motor 85 are connected to the CPU 81 via a motor control unit 83. The feeding motor 84 drives the pickup roller 22 and the feeding roller 23. The conveyance motor 85 drives the conveyance roller pair 25, the read roller pair 26, the read roller pair 30, and the discharge roller pair 31.

The operation unit 506 and the storage unit 507 are also connected to the CPU 81. The user can start a copy job and execute various settings through the operation unit 506.

In the present exemplary embodiment, the second skewing detection sensor S12 also serves as a post-separation sensor for determining when to start feeding documents. Specifically, the CPU 81 starts feeding of a sheet subsequent to a preceding sheet based on detection of a trailing edge of the preceding sheet by the second skewing detection sensor S12. As described above, by making the second skewing detection sensor S12 also serve as a post-separation sensor, the number of sensors can be reduced, so that it is possible to reduce product cost.

[Setting of Stacking Mode]

The ADF 20 can execute conveyance of documents in three stacking modes, i.e., a normal mode, a different-width mixed document mode, and a same-width mixed document mode. In the normal mode, one or a plurality of documents having the same size is set on the document tray 21 and conveyed. In the different-width mixed document mode, documents having different widths are set on the document tray 21 and conveyed. The user sets the different-width mixed document mode when documents having different widths, e.g., A5-size documents having a width of 210 mm and B5-size documents having a width of 182 mm, are collectively set on the document tray 21. In a case where images are read from the documents having different widths (different-width mixed documents), the user moves the first regulation plate 21a and the second regulation plate 21b according to a document having the greatest width, and sets a document having a smaller width to make the document abut on the second regulation plate 21b on the rear side (see FIG. 13 described below). In the same-width mixed document mode, documents having the same widths and different lengths in the sheet conveyance direction are set on the document tray 21 and conveyed. The user sets the same-width mixed document mode when documents having same widths and different lengths in the sheet conveyance direction, e.g., A5-size documents and A4R-size documents having the same widths of 210 mm, are collectively set on the document tray 21. In the following description, the different-width mixed document mode and the same-width mixed document mode may collectively be called “mixed document mode”.

FIG. 3A is a diagram illustrating an example of a screen allowing the user to perform a copy setting, and FIG. 3B is a diagram illustrating a screen allowing the user to perform a stacking mode setting. A start button 600 for inputting a start instruction of a copy job, a stacking mode setting button 601 for executing setting of the stacking mode, and a bound documents detection setting button 602 for executing setting of bound document detection are displayed on the screen in FIG. 3A. Herein, “bound documents” refer to a bundle of stapled documents. When the user presses the start button 600, the image reading apparatus 10 starts executing the image reading operation. When the user presses the stacking mode setting button 601, a screen displayed on the display panel 506a is shifted to the screen in FIG. 3B.

A normal mode selection part 603, a mixed document mode selection part 604, a different-width mixed document selection part 605, and a same-width mixed document selection part 606 are displayed on the screen in FIG. 3B. The different-width mixed document selection part 605 and the same-width mixed document selection part 606 are displayed on the screen when the user presses the mixed document mode selection part 604. The user can select an appropriate stacking mode from the screen in FIG. 3B based on the widths and the lengths of documents included in a bundle of documents the images are to be read from. For example, the user presses the different-width mixed document selection part 605 to set the different-width mixed document mode when documents having different widths are set on the document tray 21.

[Skewing Detection Sensor]

Next, the first skewing detection sensor S11 and the second skewing detection sensor S12 will be described. FIG. 4 is a top plan diagram illustrating the positions of the first skewing detection sensor S11 and the second skewing detection sensor S12. The first skewing detection sensor S11 and the second skewing detection sensor S12 are arranged downstream of the feeding roller 23 in the sheet conveyance direction. Further, the first skewing detection sensor S11 and the second skewing detection sensor S12 are arranged next to each other in the width direction. In other words, the first skewing detection sensor S11 and the second skewing detection sensor S12 are arranged in a same line with respect to the sheet conveyance direction. Although two skewing detection sensors are employed in the present exemplary embodiment, the number of skewing detection sensors may be three or more.

The CPU 81 can determine whether a fed document is skewed based on signals transmitted from the first skewing detection sensor S11 and the second skewing detection sensor S12. Further, the CPU 81 determines that the document is stapled when a skewing amount of the document is large. The CPU 81 determines that the document is stapled in a case where any one of the first skewing detection sensor S11 and the second skewing detection sensor S12 does not detect the document before a prescribed period of time elapses since the other one of the first skewing detection sensor S11 and the second skewing detection sensor S12 detects the document. Then, the CPU 81 stops feeding of documents in a case where the CPU 81 determines that the document is stapled.

In other words, the CPU 81 stops feeding when there is a great difference between detection timings of the first skewing detection sensor S11 and the second skewing detection sensor S12. For example, the CPU 81 stops feeding in a case where the second skewing detection sensor S12 does not detect the document even after a prescribed period of time elapses since the first skewing detection sensor S11 detects the document. The skewing detection processing executed by the CPU 81 will be described below.

[Flip-Up Detection Sensor]

Next, the light emitting portion S21 and the light receiving portion S22 serving as flip-up detection sensors will be described. FIG. 15 is a perspective diagram of the image reading apparatus 10. As illustrated in FIG. 15, the ADF 20 includes a first wall portion 33 and a second wall portion 34 perpendicularly extending from a supporting face of the document tray 21 for supporting documents. The first wall portion 33 and the second wall portion 34 are a pair of walls arranged to face each other with the supporting face of the document tray 21 therebetween. The first wall portion 33 is arranged on the front side of the first regulation plate 21a, and the second wall portion 34 is arranged on the rear side of the second regulation plate 21b. The light emitting portion S21 is arranged on the first wall portion 33, and the light receiving portion S22 is arranged on the second wall portion 34. In other words, the light emitting portion S21 and the light receiving portion S22 are arranged and spaced in the width direction, with the supporting face of the document tray 21 therebetween.

FIG. 5 is a perspective diagram illustrating the positions of the light emitting portion S21 and the light receiving portion S22. As illustrated in FIG. 5, the light emitting portion S21 and the light receiving portion S22 are arranged above the supporting face of the document tray 21 in the vertical direction. Further, the light emitting portion S21 and the light receiving portion S22 are arranged upstream of the separation nip formed by the feeding roller 23 and the separation roller 24 in the sheet conveyance direction.

The CPU 81 can determine whether a document is stapled based on the signal from the light receiving portion S22. The CPU 81 determines that the document is stapled and stops feeding in a case where a light path from the light emitting portion S21 to the light receiving portion S22 is intercepted by the document. The flip-up detection processing executed by the CPU 81 will be described below.

[Bound Documents Detection Processing]

Next, processing for detecting bound documents will be described with reference to a flowchart. FIG. 6 is a flowchart illustrating processing of the document feeding operation executed by the CPU 81. When power is supplied to the printer 100, the CPU 81 starts the processing illustrated in the flowchart in FIG. 6.

First, in step S101, the CPU 81 determines whether documents are stacked on the document tray 21 based on the signal from the document presence/absence sensor S31. In a case where documents are not stacked on the document tray 21 (NO in step S101), the CPU 81 does not advance the processing to next step, and waits until documents are stacked on the document tray 21.

In a case where the CPU 81 determines that documents are stacked on the document tray 21 (YES in step S101), the processing proceeds to step S102. In step S102, the CPU 81 determines whether a feeding start instruction is issued by the user. In a case where the feeding start instruction is not issued (NO in step S102), the CPU 81 does not advance the processing to next step, and waits until the feeding start instruction is issued. In a case where the CPU 81 determines that the feeding start instruction is issued (YES in step S102), the processing proceeds to step S103. In step S103, the CPU 81 starts feeding of documents.

When feeding of documents is started, in step S104, the CPU 81 determines whether the different-width mixed document mode is selected. In a case where the different-width mixed document mode is not selected (NO in step S104), the CPU 81 concurrently executes both of the flip-up detection processing in step S105 and the skewing detection processing in step S106. A case where the different-width mixed document mode is not selected in step S104 is a case where the normal mode or the same-width mixed document mode is selected.

In a case where the different-width mixed document mode is selected (YES in step S104), the processing proceeds to step S105. In step S105, the CPU 81 executes only the flip-up detection processing, and does not execute the skewing detection processing. The flip-up detection processing and the skewing detection processing will be described below.

After the flip-up detection processing or the skewing detection processing is ended, in step S107, the CPU 81 determines whether skewing or flip-up of the document is detected. In a case where skewing or flip-up of the document is detected (YES in step S107), the processing proceeds to step S108. In step S108, the CPU 81 stops feeding of documents by stopping the feeding motor 84 and the conveyance motor 85. In a case where skewing or flip-up of the document is detected, the CPU 81 displays a message indicating a possibility of stapled documents on the display panel 506a.

In a case where skewing or flip-up of the document is not detected (NO in step S107), the processing proceeds to step S109. In step S109, based on the signal from the document presence/absence sensor S31, the CPU 81 determines whether the conveyed document is a last document. In a case where the conveyed document is the last document (YES in step S109), the processing proceeds to step S108. In step S108, the CPU 81 stops the feeding motor 84 and the conveyance motor 85. In a case where the conveyed document is not the last document (NO in step S109), the processing returns to step S103, so that feeding of a next document is started. The CPU 81 repeatedly executes the above-described processing, and ends the processing of this flowchart when conveyance of the last document is completed.

[Flip-Up Detection Processing]

Next, the flip-up detection processing executed in step S105 in FIG. 6 will be described. FIG. 7 is a flowchart illustrating the flip-up detection processing executed by the CPU 81.

In the following description, a state where the light receiving portion S22 receives light from the light emitting portion S21 is called “non-detected state”, and a state where the light receiving portion S22 does not receive light from the light emitting portion S21 is called “detected state”.

First, movement of the document when flip-up occurs will be described prior to the description of the flowchart of the flip-up detection processing. FIGS. 8A to 8C are perspective diagrams illustrating movement of documents when a bound document Dst is fed. FIG. 8A illustrates a state where the bound document Dst is stacked, FIG. 8B illustrates a state where the bound document Dst is fed to the feeding roller 23, and FIG. 8C illustrates a state where flip-up occurs in the bound document Dst. The bound document Dst is a bundle of documents in which a first document sheet Dst1 and a second document sheet Dst2 are bound with a staple ST. Further, FIGS. 9A and 9B are perspective diagrams illustrating movement of a document when an unstapled normal document D is fed. FIG. 9A illustrates a state where the normal document D is conveyed, and FIG. 9B illustrates a state where the conveyed normal document D has passed the second skewing detection sensor S12.

When feeding is started in a state where the bound document Dst is stacked on the document tray 21 as illustrated in FIG. 8A, the bound document Dst is conveyed to the separation nip formed by the feeding roller 23 and the separation roller 24 by the pickup roller 22. When the bound document Dst reaches the separation nip as illustrated in FIG. 8B, the first document sheet Dst1 and the second document sheet Dst2 are conveyed to be separated from each other. At this time, while the first document sheet Dst1 is conveyed forward in the sheet conveyance direction, the second document sheet Dst2 is stopped by the separation roller 24 to remain in the document tray 21. However, because the first document sheet Dst1 and the second document sheet Dst2 are bound with the staple ST, the first document sheet Dst1 may be flipped and turned up due to force received from the respective rollers 23 and 24. When the first document sheet Dst1 is flipped up as illustrated in FIG. 8C, light emitted from the light emitting portion S21 is caught by the first document sheet Dst1 at a point A, so that a light path from the light emitting portion S21 to the light receiving portion S22 is intercepted. Therefore, the light receiving portion S22 is brought into a detected state, and the CPU 81 can determine that flip-up of the document has occurred.

On the other hand, in a case where the unstapled normal document D is conveyed as illustrated in FIG. 9A, the light receiving portion S22 is constantly brought into a non-detected state. Then, as illustrated in FIG. 9B, when a trailing end of the document D passes the second skewing detection sensor S12 while the light receiving portion S22 remains in the non-detected state, the CPU 81 determines that flip-up of the document has not occurred.

FIGS. 10A to 10C are perspective diagrams illustrating movement of a document when bound document Dst stapled at the trailing end portion thereof is fed. FIG. 10A illustrates a state where the bound document Dst is stacked, FIG. 10B illustrates a state where the bound document Dst is fed to the feeding roller 23, and FIG. 10C illustrates a state where flip-up occurs in the bound document Dst. While the bound document Dst in FIG. 8 is stapled at the leading end portion, the bound document Dst in FIG. 10 is stapled at the trailing end portion. In a case where the bound document Dst stapled at the trailing end portion illustrated in FIG. 10A is fed, the bound document Dst is conveyed to the feeding roller 23 without being flipped up as illustrated in FIG. 10B. However, at the separation nip, only the first document sheet Dst1 is conveyed forward in the sheet conveyance direction, and the second document sheet Dst2 remains in the document tray 21. Therefore, the stapled trailing end portion of the bound document Dst is flipped up. As a result, a light path from the light emitting portion S21 to the light receiving portion S22 is intercepted, so that the light receiving portion S22 is brought into a detected state. As described above, even when a position of the staple ST is different, the CPU 81 can detect flip-up of the document.

The flowchart of the flip-up detection processing will be described below. When the flip-up detection processing is started, in step S201, the CPU 81 determines whether the light receiving portion S22 is a detected state. In a case where the light receiving portion S22 is a non-detected state (NO in step S201), the processing proceeds to step S202. In step S202, the CPU 81 determines whether the second skewing detection sensor S12 is changed to OFF (i.e., a state where the document is not detected) from ON (i.e., a state where the document is detected).

In a case where the second skewing detection sensor S12 is ON (NO in step S202), the processing returns to step S201.

In a case where the light receiving portion S22 is brought into a detected state (YES in step S201) in step S201, the processing proceeds to step S203. In step S203, the CPU 81 determines that flip-up of the document has occurred, and ends the flip-up detection processing. In step S203, the CPU 81 records the occurrence of flip-up of the document in the storage unit 507. On the other hand, in a case where the second skewing detection sensor S12 is OFF while the light receiving portion S22 remains in the non-detected state (YES in step S202), the processing proceeds to step S204. In step S204, the CPU 81 determines that flip-up of the document has not occurred, and ends the flip-up detection processing. In step S204, the CPU 81 records the non-occurrence of flip-up of the document in the storage unit 507.

As described above, in a case where the bound document Dst intercepts the light path from the light emitting portion S21 to the light receiving portion S22 to cause the light receiving portion S22 to be brought into a detected state, the CPU 81 determines that flip-up of the documents has occurred (the documents are stapled). Then, as described in step S107, the CPU 81 stops feeding of the documents when flip-up of the document occurs.

[Skewing Detection Processing]

Next, the skewing detection processing in step S106 in FIG. 6 will be described with reference to a flowchart. FIG. 11 is a flowchart illustrating the skewing detection processing executed by the CPU 81.

First, movement of the document when skewing occurs will be described prior to the description of the flowchart of the skewing detection processing. FIGS. 12A and 12B are top plan diagrams illustrating movement of a document when bound document Dst is fed. FIG. 12A illustrates a state where the bound document Dst is stacked, and FIG. 12B illustrates a state where the bound document Dst is fed and skewing has occurred.

When feeding is started in a state where the bound document Dst is stacked on the document tray 21 as illustrated in FIG. 12A, the bound document Dst is conveyed to the separation nip formed by the feeding roller 23 and the separation roller 24 by the pickup roller 22. When the bound document Dst reaches the separation nip as illustrated in FIG. 12B, the first document sheet Dst1 and the second document sheet Dst2 are conveyed to be separated from each other. At this time, while the first document sheet Dst1 is conveyed forward in the sheet conveyance direction, the second document sheet Dst2 is stopped by the separation roller 24 to remain in the document tray 21. However, because the first document sheet Dst1 and the second document sheet Dst2 are bound with the staple ST, the first document sheet Dst1 may rotated with the staple ST as a center.

At this time, the first skewing detection sensor S11 is OFF because the side of the document Dst1 bound with the staple ST is not conveyed. On the other hand, the second skewing detection sensor S12 is ON because another side of the document Dst1 which is not bound with the staple ST is conveyed to the downstream side. Therefore, the CPU 81 can determine skewing of the document based on a difference in timing when the two skewing detection sensors become ON.

The flowchart of the skewing detection processing will be described below. First, in step S301, the CPU 81 determines whether the first skewing detection sensor S11 is ON. In a case where the first skewing detection sensor S11 is not ON (NO in step S301), the processing proceeds to step S302. In step S302, the CPU 81 determines whether the second skewing detection sensor S12 is ON. In a case where the second skewing detection sensor S12 is ON in step S302 (YES in step S302), the processing proceeds to step S303. In step S303, the CPU 81 determines whether the first skewing detection sensor S11 is ON. In other words, in step S303, the CPU 81 determines whether the first skewing detection sensor S11 becomes ON after the second skewing detection sensor S12 has become ON in step S302. Herein, in a case where the first skewing detection sensor S11 is OFF (NO in step S303), the processing proceeds to step S304. In step S304, the CPU 81 determines whether a prescribed period of time Tth [ms] elapsed since the second skewing detection sensor S12 was ON. In a case where the prescribed period of time Tth [ms] has passed since the second skewing detection sensor S12 was ON (YES in step S304), while the first skewing detection sensor S11 remains OFF, the processing proceeds to step S305. In step S305, the CPU 81 determines that skewing of the document has occurred. In step S305, the CPU 81 records the occurrence of skewing of the document in the storage unit 507.

On the other hand, in a case where the first skewing detection sensor S11 is ON before the prescribed time Tth [ms] has elapsed since the second skewing detection sensor S12 was ON (YES in step S303), the processing proceeds to step S308. In step S308, the CPU 81 waits until the second skewing detection sensor S12 is OFF.

When the second skewing detection sensor S12 is OFF in step S308 (YES in step S308), the processing proceeds to step S309. In step S309, the CPU 81 determines that skewing does not occur, and ends the skewing detection processing. In step S309, the CPU 81 records the non-occurrence of skewing of the document in the storage unit 507.

In a case where the first skewing detection sensor S11 is ON in step S301 (YES in step S301), the processing proceeds to step S306. In step S306, the CPU 81 determines whether the second skewing detection sensor S12 is ON. In other words, in step S306, the CPU 81 determines whether the second skewing detection sensor S12 becomes ON after the first skewing detection sensor S11 has become ON in step S301. Herein, in a case where the second skewing detection sensor S12 is OFF (NO in step S306), the processing proceeds to step S307. In step S307, the CPU 81 determines whether a prescribed period of time Tth [ms] has elapsed since the first skewing detection sensor S11 was ON. In a case where the prescribed period of time Tth [ms] has elapsed since the first skewing detection sensor S11 was ON (YES in step S307), while the second skewing detection sensor S12 remains OFF, the processing proceeds to step S305. In step S305, the CPU 81 determines that skewing of the document has occurred.

On the other hand, in a case where the second skewing detection sensor S12 is ON before the prescribed time Tth [ms] has passed since the first skewing detection sensor S11 was ON (YES in step S306), the processing proceeds to step S308. When the second skewing detection sensor S12 is OFF in step S308 (YES in step S308), the processing proceeds to step S309. In step S309, the CPU 81 determines that skewing has not occurred, and ends the skewing detection processing.

Herein, the prescribed period of time Tth is a value determined depending on a conveyance speed, e.g., 30 ms. However, a value of the prescribed period of time Tth is not limited thereto. Further, a value of the prescribed period of time Tth can be different in steps S304 and S307.

As described above, in a case where any one of the first skewing detection sensor S11 and the second skewing detection sensor S12 does not detect the document before a prescribed time elapses since the other of the first skewing detection sensor S11 and the second skewing detection sensor S12 has detected the document, the CPU 81 determines that skewing of the document has occurred (the documents are stapled). Then, as described in step S107, the CPU 81 stops feeding of documents when skewing occurs in the document.

[Arrangement of Documents in Different-Width Mixed Document Mode]

Next, a setting method of documents in the different-width mixed document mode will be described. FIG. 13A is a top plan diagram of the document tray 21 on which documents are stacked in the different-width mixed document mode. FIG. 13B is a top plan diagram illustrating a state where a document having a small width is conveyed in the different-width mixed document mode.

As illustrated in FIGS. 13A and 13B, a document D1 having a small width and a document D2 having a large width are stacked on the document tray 21.

As described above, in the different-width mixed document mode, documents having different widths are stacked on the document tray 21 and fed therefrom. As illustrated in FIG. 13A, in the different-width mixed document mode, the user moves the first regulation plate 21a and the second regulation plate 21b according to the document D2 having the largest width. Therefore, an edge of the document D2 having the largest width, located on the front side in the width direction, abuts on the first regulation plate 21a, whereas another edge thereof, located on the rear side, abuts on the second regulation plate 21b. On the other hand, the document D1 having a small width is set based on the second regulation plate 21b on the rear side. In other words, an edge of the document D1 having a small width, located on the front side in the width direction, is separated from the first regulation plate 21a, whereas another edge thereof, located on the rear side, abuts on the second regulation plate 21b. In addition, when the user selects the different-width mixed document mode via the operation unit 506, a screen prompting the user to set and align all of documents with the second regulation plate 21b on the rear side is displayed on the display panel 506a.

As illustrated in FIG. 13B, when feeding of different-width mixed documents is started, the document D1 having a small width may not pass a detection position of the first skewing detection sensor 11 while passing a detection position of the second skewing detection sensor S12. In this case, there is a risk that the CPU 81 erroneously detects occurrence of skewing if the above-described skewing detection processing is executed. This happens because the prescribed period of time Tth [ms] elapses since the second skewing detection sensor S12 detects the document, while the first skewing detection sensor S11 remains OFF (YES in step S304).

However, according to the present exemplary embodiment, the CPU 81 only executes the flip-up detection processing without executing the skewing detection processing in a case where the different-width mixed document mode is selected. With this configuration, the CPU 81 can be prevented from erroneously detecting occurrence of skewing of a document in the different-width mixed document mode. Further, even when the different-width mixed document mode is selected, staples can be detected by the flip-up detection processing. Therefore, by executing staple detection in the different-width mixed document mode, the CPU 81 can prevent documents from being fed and damaged.

In addition, according to the present exemplary embodiment, the CPU 81 does not execute the skewing detection processing in a case where the different-width mixed document mode is selected. However, the CPU 81 may execute the skewing detection processing in the different-width mixed document mode and ignore a result of skewing detection. In other words, the CPU 81 may continuously execute feeding in the different-width mixed document mode even in a case where skewing of a document is detected through the skewing detection processing. Further, the CPU 81 may control the power source not to supply power to the first skewing detection sensor S11 and the second skewing detection sensor S12 in the different-width mixed document mode.

Next, a second exemplary embodiment according to the present disclosure will be described. A basic configuration of the printer 100 according to the present exemplary embodiment is similar to the configuration described in the first exemplary embodiment. Therefore, descriptions thereof are omitted. FIG. 14 is a diagram illustrating an example of a screen allowing the user to perform a setting of bound documents detection. When the user presses the bound documents detection setting button 602 in the above-described screen in FIG. 3A, the screen displayed on the display panel 506a is shifted to the screen illustrated in FIG. 14.

A skewing detection setting portion 607 and a flip-up detection setting portion 608 are displayed on the screen in FIG. 14. As a first setting, the user can select whether to turn ON (enable) or OFF (disable) the skewing detection of the ADF 20 via the skewing detection setting portion 607. In a case where ON is selected at the skewing detection setting portion 607, the CPU 81 stops feeding based on a result of the above-described skewing detection processing when skewing of a document occurs. In a case where OFF is selected at the skewing detection setting portion 607, the CPU 81 ignores a result of the skewing detection processing and continuously executes feeding even when the CPU 81 determines that skewing of a document has occurred.

As a second setting, the user can select whether to turn ON (enable) or OFF (disable) the flip-up detection of the ADF 20 via the flip-up detection setting portion 608. In a case where ON is selected at the flip-up detection setting portion 608, the CPU 81 stops feeding based on a result of the above-described flip-up detection processing when flip-up of a document has occurred. In a case where OFF is selected at the flip-up detection setting portion 608, the CPU 81 ignores a result of the flip-up detection processing and continuously executes feeding even when the CPU 81 determines that flip-up of a document has occurred.

In addition, the CPU 81 may be configured not to execute the skewing detection processing in a case where OFF is selected at the skewing detection setting portion 607. Further, the CPU 81 may be configured not to execute the flip-up detection processing in a case where OFF is selected at the flip-up detection setting portion 608.

As described above, if the user is allowed to perform the bound documents detection setting, the user can arbitrarily select whether to execute skewing detection and flip-up detection depending on sizes of documents to be fed. For example, in a case where documents to be read are mixed documents having different widths, the user sets the skewing detection to OFF and sets the flip-up detection to ON. In this way, similar to the first exemplary embodiment, the CPU 81 is prevented from erroneously detecting occurrence of skewing of a document in the different-width mixed document mode. Further, even when the different-width mixed document mode is selected, staples can be detected by the flip-up detection processing. Therefore, by executing staple detection in the different-width mixed document mode, the CPU 81 can prevent documents from being fed and damaged.

Further, for example, in a case where tightly curled documents are stacked on the document tray 21, there is a possibility that the CPU 81 erroneously detects occurrence of flip-up of a document due to a light path from the light emitting portion S21 to the light receiving portion S22 being intercepted by a curled portion of the document. However, according to the present exemplary embodiment, the user can optionally perform the bound document detection setting depending on a state of documents. Therefore, it is possible to reduce occurrence of the erroneous detection.

According to the present disclosure, it is possible to provide a sheet conveyance apparatus, an image reading apparatus, and an image forming apparatus, capable of detecting bound documents even in a case where mixed documents having different widths are processed.

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 Japanese Patent Application No. 2023-090550, filed May 31, 2023, which is hereby incorporated by reference herein in its entirety.

Claims

1. A sheet conveyance apparatus comprising: a stacking portion on which sheets are to be stacked;a feeding portion configured to separate and feed the sheets stacked on the stacking portion one by one;a first detection unit configured to detect skewing of the sheet fed by the feeding portion;a second detection unit configured to detect flip-up of the sheet fed by the feeding portion;a controller configured to stop feeding executed by the feeding portion in a case where skewing of the sheet is detected by the first detection unit and in a case where flip-up of the sheet is detected by the second detection unit; anda setting unit configured to set a different-width mixed document mode in which a plurality of sheets having different widths is stacked on the stacking portion,wherein, in a case where the different-width mixed document mode is set by the setting unit, the controller does not stop feeding based on skewing detected by the first detection unit but stops feeding based on flip-up detected by the second detection unit.

2. The sheet conveyance apparatus according to claim 1, wherein the first detection unit includes a first sensor that is for detecting the sheet fed by the feeding portion and a second sensor that is for detecting the sheet fed by the feeding portion and is arranged next to the first sensor in a width direction, andwherein the controller stops feeding executed by the feeding portion in a case where any one of the first sensor or the second sensor does not detect a sheet before a prescribed period of time elapses since the other one of the first sensor or the second sensor detected the sheet.

3. The sheet conveyance apparatus according to claim 2, wherein the controller starts feeding of a subsequent sheet which follows a preceding sheet when a trailing edge of the preceding sheet is detected by the second sensor.

4. The sheet conveyance apparatus according to claim 1, wherein the second detection unit includes a light emitting portion and a light receiving portion arranged above the stacking portion, andwherein the controller stops feeding executed by the feeding portion in a case where a light path from the light emitting portion to the light receiving portion is intercepted by a sheet after feeding is started by the feeding portion.

5. The sheet conveyance apparatus according to claim 1, wherein the setting unit is capable of setting the different-width mixed document mode and a same-width mixed document mode in which plural sheets having the same widths and different lengths in a conveyance direction is stacked on the stacking portion, andwherein, in a case where the same-width mixed document mode is set by the setting unit, the controller stops both of the feeding based on skewing detected by the first detection unit and the feeding based on flip-up detected by the second detection unit.

6. The sheet conveyance apparatus according to claim 1, further comprising a display portion configured to display a message wherein, in a case where skewing is detected by the first detection unit and in a case where flip-up is detected by the second detection unit, the display portion displays a message indicating that the sheets stacked on the stacking portion are likely to be bound documents.

7. A sheet conveyance apparatus comprising: a stacking portion on which sheets are to be stacked;a feeding portion configured to separate and feed the sheets stacked on the stacking portion one by one;a first detection unit configured to detect skewing of the sheet fed by the feeding portion;a second detection unit configured to detect flip-up of the sheet fed by the feeding portion;a controller configured to determine that the sheets stacked on the stacking portion are bound documents in a case where skewing of the sheet is detected by the first detection unit and in a case where flip-up of the sheet is detected by the second detection unit; anda setting unit configured to set a different-width mixed document mode in which a plurality of sheets having different widths is stacked on the stacking portion,wherein, in a case where the different-width mixed document mode is set by the setting unit, the controller does not execute determination of bound documents based on skewing detected by the first detection unit but executes determination of bound documents based on flip-up detected by the second detection unit.

8. A sheet conveyance apparatus comprising: a stacking portion on which sheets are to be stacked;a feeding portion configured to separate and feed the sheets stacked on the stacking portion one by one;a first detection unit which includes a first sensor that is for detecting the sheet fed by the feeding portion and a second sensor that is for detecting the sheet fed by the feeding portion and is arranged next to the first sensor in a width direction;a second detection unit which includes a light emitting portion and a light receiving portion arranged above the stacking portion;a controller configured to stop feeding executed by the feeding portion in a case where any one of the first sensor or the second sensor does not detect a sheet before a prescribed period of time elapses since the other one of the first sensor or the second sensor detected the sheet and in a case where a light path from the light emitting portion to the light receiving portion is intercepted by a sheet; anda setting unit configured to set a different-width mixed document mode in which a plurality of sheets having different widths is stacked on the stacking portion,wherein, in a case where the different-width mixed document mode is set by the setting unit, the controller does not stop feeding based on a detection result by the first detection unit but stops feeding based on a detection result by the second detection unit.

9. A sheet conveyance apparatus comprising: a stacking portion on which sheets are to be stacked;a feeding portion configured to separate and feed the sheets stacked on the stacking portion one by one;a first detection unit configured to detect skewing of the sheet fed by the feeding portion;a second detection unit configured to detect flip-up of the sheet fed by the feeding portion;a controller configured to stop feeding executed by the feeding portion in a case where skewing of the sheet is detected by the first detection unit and in a case where flip-up of the sheet is detected by the second detection unit; anda setting unit configured to set a first setting for enabling or disabling detection of skewing of a sheet executed by the first detection unit and a second setting for enabling or disabling detection of flip-up of a sheet executed by the second detection unit.

10. An image reading apparatus comprising: the sheet conveyance apparatus according to claim 1; anda reading unit configured to read images of sheets conveyed by the sheet conveyance apparatus.

11. An image forming apparatus comprising: an image reading apparatus having the sheet conveyance apparatus according to claim 1, and having a reading unit configured to read images of sheets conveyed by the sheet conveyance apparatus; andan image forming unit configured to form images on a recording material based on image information of a sheet read by the image reading apparatus.