Sheet transporting device, image forming apparatus and method of controlling operation

Abstract

To provide a sheet transporting device, image forming apparatus and method of controlling operation allowing for suppressing the occurrence of a trouble related to one pair of transport members used to correct the position of a sheet.SOLUTION: An image forming apparatus 100 comprises a third sensor 54 that detects the position in a width direction of a sheet being carried, a movement control section 55 that controls the movement of the sheet along the width direction of a correction roller pair under clamping the sheet based on the amount of deviation between a detection position as detected by the third sensor 54 and a sheet size-based reference position placed corresponding to a paper-feed source of the sheet, a detection processing section 61 that detects a sheet size of the sheet, and a switch-over processing section 62 that switches over between permission and non-permission to move the correction roller pair based on the sheet size placed corresponding to the paper-feed source of the sheet and the sheet size of the sheet detected by the detection processing section 61.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a sheet conveying device, an image forming apparatus, and an operation control method. [Background technology]

[0002] In an image forming apparatus such as a printer, the position of a sheet in the width direction may shift during transport of the sheet. In response to this, an image forming apparatus is known that corrects the position of the sheet in the width direction by using a pair of transport members that are movable along the width direction (see, for example, Patent Document 1). For example, in this type of image forming apparatus, the position of the sheet in the width direction is corrected based on the amount of deviation between the position of the sheet in the width direction during transport detected by a sensor and a reference position based on the sheet size associated with the paper feed source of the sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-142902 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the image forming apparatus, the sheet size associated with the sheet feed source may not match the sheet size of the sheet stored in the feed source. In this case, when the position of the sheet in the width direction is corrected, the pair of conveying members may be moved beyond the movable range, resulting in a malfunction such as the pair of conveying members becoming unable to move.

[0005] An object of the present invention is to provide a sheet conveying device, an image forming apparatus, and an operation control method that are capable of suppressing the occurrence of problems related to a pair of conveying members used for correcting the position of a sheet. [Means for solving the problem]

[0006] A sheet conveying device according to one aspect of the present invention includes a pair of conveying members, a sensor, a movement control unit, a detection processing unit, and a switching processing unit. The pair of conveying members are provided to be movable along a width direction perpendicular to a sheet conveying direction, and sandwich and convey the sheet. The sensor detects a position in the width direction of the sheet conveyed by the pair of conveying members. The movement control unit controls the movement of the pair of conveying members sandwiching the sheet along the width direction based on an amount of deviation between a detection position detected by the sensor and a reference position based on a sheet size associated with a paper feed source of the sheet. The detection processing unit detects the sheet size of the sheet. The switching processing unit switches between permission and prohibition of movement of the pair of conveying members based on the sheet size associated with the paper feed source of the sheet and the sheet size of the sheet detected by the detection processing unit.

[0007] According to another aspect of the present invention, there is provided an image forming apparatus including the sheet transporting device and an image forming section, the image forming section forming an image on the sheet transported by the sheet transporting device.

[0008] According to another aspect of the present invention, an operation control method is executed by a sheet conveying device including a pair of conveying members movable along a width direction perpendicular to a sheet conveying direction, sandwiching and conveying the sheet, a sensor detecting a position in the width direction of the sheet conveyed by the pair of conveying members, and a movement control unit controlling movement of the pair of conveying members sandwiching the sheet along the width direction based on a deviation amount between a detection position detected by the sensor and a reference position based on a sheet size associated with a sheet feed source of the sheet, and includes a detection step and a switching step. In the detection step, a sheet size of the sheet is detected. In the switching step, permission or prohibition of movement of the pair of conveying members is switched based on the sheet size associated with the sheet feed source of the sheet and the sheet size detected by the detection step. Effect of the Invention

[0009] According to the present invention, it is possible to suppress the occurrence of problems related to a pair of conveying members used for correcting the position of a sheet. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a configuration of an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a system configuration of the image forming apparatus according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a perspective view showing a configuration of a paper feed cassette of the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a right side view showing the configuration of the position correction unit of the image forming apparatus according to the embodiment of the present invention. [Diagram 5] FIG. 5 is a flowchart showing an example of an operation control process executed in the image forming apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0012] [Configuration of image forming apparatus 100] First, the configuration of an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS.

[0013] For ease of explanation, the vertical direction in the installed state (as shown in FIG. 1) in which image forming apparatus 100 can be used is defined as up-down direction D1. Also, the front side of image forming apparatus 100 shown in FIG. 1 on the page is defined as the front (front face), and the left-right direction D3 is defined based on the front face of image forming apparatus 100 in the installed state.

[0014] Image forming apparatus 100 is an image processing apparatus having a print function for forming an image based on image data on a sheet SH (see FIG. 4). Specifically, image forming apparatus 100 is a multifunction machine having multiple functions including the print function. Note that the image forming apparatus of the present invention may be a printer, a fax machine, or a copier having the print function.

[0015] As shown in FIGS. 1 and 2, an image forming apparatus 100 includes an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a sheet conveying unit 4, an operation display unit 5, a storage unit 6, and a control unit .

[0016] The ADF 1 transports an original document whose image is to be read by the image reading unit 2. The ADF 1 includes an original document setting unit, a plurality of transport rollers, an original document holder, and a paper discharge unit.

[0017] The image reading unit 2 realizes a scanning function for reading an image of a document, and includes a document table, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device).

[0018] The image forming unit 3 realizes the printing function. Specifically, the image forming unit 3 forms a color or monochrome image on the sheet SH transported by the sheet transport unit 4 according to an electrophotographic method. Note that the image forming unit 3 may also form an image on the sheet SH transported by the sheet transport unit 4 according to an inkjet method.

[0019] As shown in FIG. 1, the image forming section 3 includes a plurality of image forming units 11-14, an optical scanning device 15, an intermediate transfer belt 16, a secondary transfer roller 17, a fixing device 18, and a paper discharge tray 19. The image forming unit 11 forms a toner image on the intermediate transfer belt 16 using a Y (yellow) toner. The image forming unit 12 forms a toner image on the intermediate transfer belt 16 using a C (cyan) toner. The image forming unit 13 forms a toner image on the intermediate transfer belt 16 using an M (magenta) toner. The image forming unit 14 forms a toner image on the intermediate transfer belt 16 using a K (black) toner. Each of the plurality of image forming units 11-14 includes a photosensitive drum, a charging roller, a developing device, a primary transfer roller, and a drum cleaning unit. The optical scanning device 15 emits light based on image data toward the surface of the photosensitive drum of each of the image forming units 11-14. The toner images formed on the surfaces of the photoconductor drums of the image forming units 11 to 14 are transferred onto the intermediate transfer belt 16. The secondary transfer roller 17 transfers the toner images transferred onto the surface of the intermediate transfer belt 16 onto a sheet SH transported by the sheet transport section 4. The fixing device 18 fixes the toner images transferred onto the sheet SH by the secondary transfer roller 17 onto the sheet SH. The sheet SH onto which the toner images have been fixed by the fixing device 18 is discharged to a paper output tray 19.

[0020] The sheet conveying section 4 conveys the sheet SH, on which an image is formed by the image forming section 3, along a conveying direction D4 (see FIG. 1). The conveying direction D4 is a direction along a plane perpendicular to the front-rear direction D2.

[0021] The operation display unit 5 is a user interface of the image forming apparatus 100. The operation display unit 5 includes a display unit and an operation unit. The display unit displays various information in response to control instructions from the control unit 7. For example, the display unit is a liquid crystal display. The operation unit inputs various information to the control unit 7 in response to user operations. For example, the operation unit is a touch panel.

[0022] The storage unit 6 is a non-volatile storage device. For example, the storage unit 6 is a flash memory. The storage unit 6 may be a solid state drive (SSD) or a hard disk drive (HDD).

[0023] The control unit 7 performs overall control of the image forming apparatus 100. Note that the control unit 7 may be a control unit provided separately from a main control unit that performs overall control of the image forming apparatus 100.

[0024] As shown in FIG. 2, the control unit 7 includes a CPU 21, a ROM 22, and a RAM 23. The CPU 21 is a processor that executes various arithmetic operations. The ROM 22 is a non-volatile storage device in which information such as a control program for causing the CPU 21 to execute various processes is stored in advance. The RAM 23 is a volatile or non-volatile storage device used as a temporary storage memory (work area) for various processes executed by the CPU 21. The CPU 21 comprehensively controls the image forming apparatus 100 by executing various control programs stored in advance in the ROM 22. The control unit 7 may be composed of an electronic circuit such as an application specific integrated circuit (ASIC).

[0025] [Configuration of sheet conveying unit 4] Next, the configuration of the sheet conveying section 4 will be described with reference to FIGS.

[0026] As shown in FIG. 1, the sheet transport unit 4 includes a paper feed cassette 31, a pickup roller 32, a paper feed roller 33, a separation roller , and a sheet transport path .

[0027] The paper feed cassette 31 accommodates sheets SH on which images are formed by the image forming unit 3. For example, the paper feed cassette 31 accommodates sheets SH such as paper, coated paper, postcards, envelopes, and overhead projector sheets.

[0028] Here, in the image forming apparatus 100, a sheet size corresponding to the paper feed cassette 31 is set in response to a user's operation on the operation display unit 5.

[0029] For example, the control unit 7 causes the operation display unit 5 to display a sheet size setting screen used for setting a sheet size associated with the paper feed cassette 31 in response to a predetermined user operation on the operation display unit 5. Then, the control unit 7 sets the sheet size associated with the paper feed cassette 31 in response to the user operation on the sheet size setting screen.

[0030] 3, the paper feed cassette 31 includes a storage section 41, a lift member 42, a rear end cursor 43, a pair of side cursors 44, and a gripping section 45. The paper feed cassette 31 also includes a first sensor 46 and a second sensor 47 shown in FIG.

[0031] The storage section 41 defines a storage space for the sheet SH. As shown in Fig. 3, the storage section 41 is formed in a box shape that is open at the top.

[0032] The lift member 42 is provided to be movable up and down in the up-down direction D1 at the bottom of the storage unit 41. The lift member 42 lifts the stack of sheets SH stored in the paper feed cassette 31 to a contact position where the stack of sheets SH and the pickup roller 32 come into contact with each other.

[0033] The rear end cursor 43 is provided to be movable along the left-right direction D3 at the bottom of the storage section 41. The rear end cursor 43 comes into contact with the rear end of the sheet SH stored in the storage section 41 in the conveying direction D4 (see FIGS. 1 and 3 ) to adjust the position of the sheet SH in the storage section 41.

[0034] The pair of side cursors 44 are provided at the bottom of the storage unit 41 to be movable in the front-rear direction D2. The pair of side cursors 44 come into contact with both ends of the sheet SH stored in the storage unit 41 in the width direction D5 (see FIG. 3 ) to adjust the position of the sheet SH in the storage unit 41. The width direction D5 is a direction perpendicular to the conveying direction D4. The pair of side cursors 44 adjust the position of the sheet SH in the storage unit 41 so that the sheet SH stored in the paper feed cassette 31 is conveyed along the center of the sheet conveying path 35 in the width direction D5.

[0035] The grip portion 45 is provided at the front end portion of the sheet feed cassette 31. The grip portion 45 is used to insert and remove the sheet feed cassette 31 into and from the housing of the image forming apparatus 100.

[0036] The first sensor 46 detects the size in the transport direction D4 (see FIG. 3) of the sheet SH stored in the storage unit 41. For example, the first sensor 46 is an electric circuit that includes a first variable resistor whose electric resistance changes depending on the position of the rear end cursor 43 in the storage unit 41 and can output a first electric signal according to the electric resistance of the first variable resistor.

[0037] The second sensor 47 detects the size in the width direction D5 (see FIG. 3) of the sheet SH stored in the storage unit 41. For example, the second sensor 47 is an electric circuit that includes a second variable resistor whose electric resistance changes according to the distance between the pair of side cursors 44 and can output a second electric signal according to the electric resistance of the second variable resistor.

[0038] The pickup roller 32 is provided above the paper feed cassette 31. The pickup roller 32 comes into contact with the uppermost sheet SH in the stack of sheets SH lifted to the contact position by the lift member 42, and transports the sheet SH in a transport direction D4 (see FIGS. 1 and 3).

[0039] The paper feed roller 33 comes into contact with the upper surface of the sheet SH conveyed by the pickup roller 32, and conveys the sheet SH along a sheet conveying path .

[0040] The separation roller 34 is provided below the paper feed roller 33. The separation roller 34 is urged toward the paper feed roller 33 by an urging member (not shown). As a result, a paper feed nip portion that pinches the sheets SH is formed between the paper feed roller 33 and the separation roller 34. When multiple sheets SH are transported to the paper feed nip portion, the separation roller 34 separates the sheet SH that comes into contact with the paper feed roller 33 from the other sheets SH among the multiple sheets SH.

[0041] The sheet transport path 35 is a passageway along which the sheet SH travels from the paper feed cassette 31 to the paper discharge tray 19 via the secondary transfer roller 17 and the fixing device 18. A paper feed roller 33 and a separation roller 34 are provided in the sheet transport path 35. A plurality of transport roller pairs are also provided at intervals in the sheet transport path 35. In the sheet transport path 35, the sheet SH is transported in a transport direction D4 (see FIG. 1) by the paper feed roller 33 and the plurality of transport roller pairs.

[0042] Here, in the image forming apparatus 100, the position of the sheet SH in the width direction D5 (see FIG. 3) may be shifted during the conveyance of the sheet SH. To address this, the image forming apparatus 100 is provided with a position correction unit 8 shown in FIGS. 1, 2, and 4.

[0043] [Configuration of position correction unit 8] Next, the configuration of the position correction unit 8 will be described with reference to FIGS.

[0044] The position correction unit 8 corrects the position in the width direction D5 of the sheet SH being conveyed.

[0045] As shown in FIG. 1, the position correction unit 8 is provided on the sheet transport path 35 upstream of the secondary transfer roller 17 in the transport direction D4 and downstream of the paper feed roller 33 in the transport direction D4.

[0046] As shown in FIGS. 1, 2, and 4, the position correction unit 8 includes a correction roller pair 51, a support section 52, a movement mechanism 53, a third sensor 54, and a movement control section 55.

[0047] The correction roller pair 51 is provided to be movable along a width direction D5 (see FIG. 4) perpendicular to a conveying direction D4 (see FIG. 4) of the sheet SH, and conveys the sheet SH by sandwiching it. The correction roller pair 51 is an example of a pair of conveying members of the present invention.

[0048] Specifically, the correction roller pair 51 is composed of a drive roller that rotates by receiving a driving force supplied from a motor (not shown), and a driven roller that is provided opposite the drive roller. The driven roller is biased toward the drive roller by a biasing member (not shown). As a result, a transport nip that holds the sheet SH is formed between the drive roller and the driven roller. The correction roller pair 51 transports the sheet SH in a transport direction D4.

[0049] The support portion 52 rotatably supports the correction roller pair 51 .

[0050] As shown in Fig. 4, the support portion 52 includes a first bearing portion 52A, a second bearing portion 52B, and an extension portion 52C. The first bearing portion 52A rotatably supports the front rotating shaft of the driving roller and the front rotating shaft of the driven roller. The second bearing portion 52B rotatably supports the rear rotating shaft of the driving roller and the rear rotating shaft of the driven roller. The extension portion 52C is elongated in the width direction D5 and supports the first bearing portion 52A and the second bearing portion 52B.

[0051] The support portion 52 is supported by a housing of the image forming apparatus 100 so as to be movable along the width direction D5 (see FIG. 4). The correction roller pair 51 is provided so as to be movable integrally with the support portion 52. As a result, when the support portion 52 is moved along the width direction D5, the correction roller pair 51 supported by the support portion 52 is also moved along the width direction D5.

[0052] For example, the correction roller pair 51 is provided so that a front end 51A (see FIG. 4) of the correction roller pair 51 can move a distance L1 (see FIG. 4) from a home position P1 (see FIG. 4) to both sides in the width direction D5.

[0053] The moving mechanism 53 moves the correction roller pair 51 along the width direction D5. Specifically, the moving mechanism 53 includes a motor that generates a driving force for moving the correction roller pair 51 and the support portion 52, and a power transmission mechanism that transmits the driving force generated by the motor to the support portion 52. The support portion 52 is moved along the width direction D5 by the driving force transmitted from the moving mechanism 53.

[0054] The third sensor 54 detects the position in the width direction D5 of the sheet SH transported by the correction roller pair 51. The third sensor 54 is an example of the sensor of the present invention.

[0055] 4, the third sensor 54 is provided downstream of the correction roller pair 51 in the sheet transport path 35 in the transport direction D4. The third sensor 54 may be provided upstream of the correction roller pair 51 in the sheet transport path 35 in the transport direction D4.

[0056] For example, the third sensor 54 is a contact image sensor (CIS) long in the width direction D5. The third sensor 54 is provided so as to face one end (rear end in the front-rear direction D2) of the sheet SH conveyed along the sheet conveying path 35 in the width direction D5. Specifically, the third sensor 54 is provided so as to face an area (rear area in the front-rear direction D2) on one side of the center of the width direction D5 in the sheet conveying path 35. When the sheet SH passes a position facing the third sensor 54 in the sheet conveying path 35, the third sensor 54 captures an image of one end (rear end in the front-rear direction D2) of the sheet SH in the width direction D5, and outputs imaging data indicating the position of the end. The imaging data output from the third sensor 54 is input to the movement control unit 55. The third sensor 54 may be a transmission type or reflection type optical sensor arranged side by side along the width direction D5.

[0057] The movement control unit 55 controls the movement of the correction roller pair 51 clamping the sheet SH along the width direction D5 based on the amount of deviation between the detection position detected by the third sensor 54 and a reference position based on the sheet size associated with the paper feed source (paper feed cassette 31) of the sheet SH.

[0058] For example, the movement control unit 55 is configured with an electronic circuit such as an application specific integrated circuit (ASIC).

[0059] Here, the reference position is the position of one end of the sheet SH in the width direction D5 (the rear end in the front-rear direction D2) when the sheet SH of the sheet size associated with the paper feed cassette 31 passes through a position facing the third sensor 54 in the sheet transport path 35 without being shifted in the width direction D5. In the image forming apparatus 100, the reference position corresponding to each sheet size of the sheet SH that can be accommodated in the paper feed cassette 31 is determined in advance. For example, the movement control unit 55 recognizes the reference position in response to a notification from the control unit 7.

[0060] For example, the deviation amount is a positive value when the position of one end (rear end in the front-rear direction D2) of the sheet SH in the width direction D5 specified based on the imaging data output from the third sensor 54 is rearward in the front-rear direction D2 from the reference position. Also, the deviation amount is a negative value when the position of one end (rear end in the front-rear direction D2) of the sheet SH in the width direction D5 specified based on the imaging data output from the third sensor 54 is forward in the front-rear direction D2 from the reference position.

[0061] When the amount of deviation is a positive value, the movement control unit 55 controls the movement mechanism 53 to move the correction roller pair 51, which is sandwiching the sheet SH, forward in the front-rear direction D2 by an amount equal to the amount of deviation. When the amount of deviation is a negative value, the movement control unit 55 controls the movement mechanism 53 to move the correction roller pair 51, which is sandwiching the sheet SH, backward in the front-rear direction D2 by an amount equal to the amount of deviation. In other words, the movement control unit 55 moves the correction roller pair 51, which is sandwiching the sheet SH, so that one end of the sheet SH in the width direction D5 (the end on the rear side in the front-rear direction D2) is positioned at the reference position.

[0062] Incidentally, in the image forming apparatus 100, the sheet size associated with the paper feed source of the sheets SH (paper feed cassette 31) may not match the sheet size of the sheets SH accommodated in the paper feed source. In a conventional image forming apparatus, if the sheet size associated with the paper feed source of the sheets SH does not match the sheet size of the sheets SH accommodated in the paper feed source, and the position of the sheets SH in the width direction D5 is corrected, the correction roller pair 51 may move beyond the movable range, causing a malfunction such as the correction roller pair 51 becoming unable to move.

[0063] In contrast, in the image forming apparatus 100 according to the embodiment of the present invention, it is possible to suppress the occurrence of problems related to the correction roller pair 51, as will be described below.

[0064] [Configuration of control unit 7] Next, the configuration of the control unit 7 will be described in more detail with reference to FIG.

[0065] 2, the control unit 7 includes a detection processing unit 61, a switching processing unit 62, and a notification processing unit 63. An apparatus including the sheet conveying unit 4, the control unit 7, and the position correction unit 8 is an example of a sheet conveying apparatus of the present invention. Note that the present invention may be applied to the ADF 1.

[0066] Specifically, the ROM 22 of the control unit 7 stores in advance an operation control program for causing the CPU 21 of the control unit 7 to function as each of the above-mentioned processing units. The CPU 21 of the control unit 7 executes the operation control program stored in the ROM 22 to function as each of the above-mentioned processing units. Note that some or all of the processing units included in the control unit 7 may be configured with electronic circuits. The operation control program may also be a program for causing a plurality of processors to function as each of the processing units included in the control unit 7. The control unit 7 may also include a movement control unit 55.

[0067] The detection processing unit 61 detects the sheet size of the sheet SH.

[0068] For example, the detection processing unit 61 detects the sheet size of the sheets SH contained in the paper feed cassette 31 using the first sensor 46 and the second sensor 47. Specifically, the detection processing unit 61 identifies the sheet size of the sheets SH contained in the paper feed cassette 31 based on the size of the sheets SH detected by the first sensor 46 in the transport direction D4 and the size of the sheets SH detected by the second sensor 47 in the width direction D5.

[0069] The detection processing unit 61 may detect the sheet size of the sheet SH accommodated in the sheet feed cassette 31 by using a sheet sensor (not shown) that detects the sheet SH upstream of the position correction unit 8 in the sheet transport path 35 in the transport direction D4. Specifically, the detection processing unit 61 may calculate the size of the sheet SH in the transport direction D4 based on the detection time of the sheet SH by the sheet sensor and the transport speed of the sheet SH by the sheet transport unit 4, and specify the sheet size of the sheet SH based on the calculation result.

[0070] The switching processing unit 62 switches between permission and prohibition of movement of the correction roller pair 51 based on the sheet size associated with the paper feed source of the sheet SH and the sheet size of the sheet SH detected by the detection processing unit 61.

[0071] For example, the switching processing unit 62 allows the movement of the correction roller pair 51 when the sheet size associated with the paper feed source of the sheet SH is included in the sheet size group corresponding to the sheet size of the sheet SH detected by the detection processing unit 61, and does not allow the movement of the correction roller pair 51 when the sheet size is not included in the sheet size group.

[0072] Here, the sheet size group corresponding to the sheet size detected by the detection processing unit 61 includes the sheet size. The sheet size group corresponding to the sheet size detected by the detection processing unit 61 includes some or all of a plurality of sheet sizes whose size difference in the width direction D5 between the sheet size and the detected sheet size is equal to or less than twice the amount of correction (distance L1 shown in FIG. 4) that can be made by the position correction unit 8. In the image forming apparatus 100, the sheet size group corresponding to each sheet size of the sheets SH that can be accommodated in the sheet feed cassette 31 is determined in advance.

[0073] For example, when the sheet size associated with the paper feed cassette 31 is included in the sheet size group corresponding to the sheet sizes detected by the detection processing unit 61, the switching processing unit 62 transmits a first control signal to the movement control unit 55 to permit the movement of the correction roller pair 51 and notifies the movement control unit 55 of the reference position when the sheet size associated with the paper feed cassette 31 is not included in the sheet size group corresponding to the sheet sizes detected by the detection processing unit 61, the switching processing unit 62 transmits a second control signal to the movement control unit 55 to prohibit the movement of the correction roller pair 51. Instead of transmitting the second control signal, the switching processing unit 62 may stop the supply of power to the movement mechanism 53, the third sensor 54, and the movement control unit 55.

[0074] In addition, the switching processing unit 62 may allow the movement of the correction roller pair 51 when the sheet size associated with the paper feed source of the sheet SH matches the sheet size of the sheet SH detected by the detection processing unit 61, and may not allow the movement of the correction roller pair 51 when they do not match.

[0075] When the switching processing unit 62 does not permit the movement of the correction roller pair 51, the notification processing unit 63 issues a notification to that effect.

[0076] For example, the notification processor 63 causes the operation display unit 5 to display a message indicating that the position of the sheet SH is not corrected because the sheet size associated with the sheet feed cassette 31 does not match the sheet size of the sheet SH contained in the sheet feed cassette 31. The notification processor 63 may output audio data including the message.

[0077] [Motion control processing] 5, an example of the procedure of the operation control process executed by the control unit 7 in the image forming apparatus 100 will be described together with the operation control method of the present invention. When an image forming process for forming an image on a sheet SH is executed, the operation control process is executed before the image forming process.

[0078] <Step S11> First, in step S11, the control section 7 detects the sheet size of the sheet SH. Here, the process of step S11 is an example of a detection step of the present invention, and is executed by the detection processing section 61 of the control section 7.

[0079] Specifically, the control unit 7 determines the sheet size of the sheet SH stored in the paper feed cassette 31 based on the size of the sheet SH in the conveying direction D4 detected by the first sensor 46 and the size of the sheet SH in the width direction D5 detected by the second sensor 47.

[0080] <Step S12> In step S12, the control unit 7 determines whether or not the sheet size associated with the paper feed cassette 31 is included in the group of sheet sizes corresponding to the sheet size detected by the process of step S11.

[0081] Here, if the control unit 7 determines that the sheet size associated with the paper feed cassette 31 is included in the sheet size group corresponding to the processing result of step S11 (Yes side of S12), it shifts the process to step S13. On the other hand, if the sheet size associated with the paper feed cassette 31 is not included in the sheet size group corresponding to the processing result of step S11 (No side of S12), it shifts the process to step S14.

[0082] <Step S13> In step S13, the control unit 7 allows the correction roller pair 51 to move.

[0083] Specifically, the control unit 7 transmits the first control signal to the movement control unit 55 and notifies the movement control unit 55 of the reference position. This enables the movement control unit 55 to correct the position of the sheet SH during the execution of the image forming process.

[0084] <Step S14> In step S14, the control unit 7 does not permit the movement of the correction roller pair 51. Here, the processes of steps S12, S13, and S14 are an example of a switching step of the present invention, and are executed by the switching processing unit 62 of the control unit 7.

[0085] Specifically, the control unit 7 transmits the second control signal to the movement control unit 55. This limits the position correction of the sheet SH by the movement control unit 55 during the execution of the image forming process.

[0086] <Step S15> In step S15, the control unit 7 issues a notification that the movement of the correction roller pair 51 is not permitted. Here, the process of step S15 is executed by the notification processing unit 63 of the control unit 7.

[0087] Specifically, the control unit 7 causes the operation display unit 5 to display the message.

[0088] In this way, in the image forming apparatus 100, permission or prohibition of movement of the correction roller pair 51 is switched based on the sheet size associated with the paper feed cassette 31 and the sheet size of the sheet SH detected by the detection processing unit 61. This makes it possible to restrict the movement of the correction roller pair 51 when the sheet size associated with the paper feed cassette 31 does not match the sheet size of the sheet SH detected by the detection processing unit 61. This makes it possible to suppress the occurrence of malfunctions such as the correction roller pair 51 moving beyond the movable range and becoming unable to move.

[0089] Furthermore, in the image forming apparatus 100, even if the sheet size associated with the paper feed cassette 31 does not match the sheet size of the sheet SH detected by the detection processing unit 61, movement of the correction roller pair 51 is permitted if the sheet size associated with the paper feed cassette 31 is included in the sheet size group corresponding to the detection result by the detection processing unit 61. This makes it possible to avoid limiting the position correction of the sheet SH even when the size difference between the sheet size associated with the paper feed cassette 31 and the sheet size of the sheet SH detected by the detection processing unit 61 is small and the correction roller pair 51 is unlikely to move beyond its movable range.

[0090] [Notes on the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0091] <Appendix 1> A sheet conveying device comprising: a pair of conveying members that are movable along a width direction perpendicular to the sheet conveying direction and that clamp and convey the sheet; a sensor that detects the position in the width direction of the sheet conveyed by the pair of conveying members; a movement control unit that controls the movement of the pair of conveying members along the width direction while clamping the sheet based on the amount of deviation between the detection position detected by the sensor and a reference position based on a sheet size associated with a paper feed source of the sheet; a detection processing unit that detects the sheet size of the sheet; and a switching processing unit that switches between allowing and disallowing the movement of the pair of conveying members based on the sheet size associated with the paper feed source of the sheet and the sheet size of the sheet detected by the detection processing unit.

[0092] <Appendix 2> The sheet conveying device described in Appendix 1, wherein the switching processing unit allows movement of the pair of conveying members when the sheet size associated with the paper feed source of the sheet matches the sheet size of the sheet detected by the detection processing unit, and does not allow movement of the pair of conveying members when they do not match.

[0093] <Appendix 3> The sheet conveying device described in Appendix 1, wherein the switching processing unit allows movement of the pair of conveying members when the sheet size associated with the paper feed source of the sheet is included in a sheet size group corresponding to the sheet size of the sheet detected by the detection processing unit, and does not allow movement of the pair of conveying members when the sheet size associated with the paper feed source of the sheet is not included in the sheet size group.

[0094] <Appendix 4> 4. The sheet conveying device according to claim 1, further comprising a notification processing section that notifies a user when the switching processing section does not permit the movement of the pair of conveying members.

[0095] <Appendix 5> 5. An image forming apparatus comprising: the sheet conveying device according to any one of claims 1 to 4; and an image forming section that forms an image on the sheet conveyed by the sheet conveying device.

[0096] <Appendix 6> An operation control method executed by a sheet conveying device comprising a pair of conveying members that are movable along a width direction perpendicular to the sheet conveying direction and that clamp and convey the sheet, a sensor that detects the position in the width direction of the sheet conveyed by the pair of conveying members, and a movement control unit that controls the movement of the pair of conveying members along the width direction while clamping the sheet based on the amount of deviation between the detection position detected by the sensor and a reference position based on the sheet size associated with the sheet feed source, the operation control method including a detection step of detecting the sheet size of the sheet, and a switching step of switching whether or not to allow movement of the pair of conveying members based on the sheet size associated with the sheet feed source and the sheet size of the sheet detected by the detection step. [Explanation of symbols]

[0097] 1 ADF 2 Image reading unit 3. Image forming section 4 Sheet transport section 5 Operation display section 6 Memory section 7 Control section 8 Position correction unit 31 Paper feed cassette 32 Pick-up roller 33 Paper feed roller 34 Separation roller 35 Sheet transport path 41 Storage unit 42 Lifting parts 43 Back end cursor 44 Pair of Side Cursors 45 Gripping part 46 First Sensor 47 Second Sensor 51 Correction roller pair 52 Support part 53 Moving mechanism 54 3rd Sensor 55 Movement control section 61 Detection processing unit 62 Switching Processing Unit 63 Notification processing section 100 Image forming device

Claims

1. a pair of conveying members that are movable along a width direction perpendicular to a conveying direction of the sheet and that sandwich and convey the sheet; a sensor for detecting a position in the width direction of the sheet conveyed by the pair of conveying members; a movement control unit that controls movement of the pair of conveying members that are clamping the sheet along the width direction based on an amount of deviation between a detection position detected by the sensor and a reference position based on a sheet size associated with a sheet feed source of the sheet; a detection processing unit for detecting a sheet size of the sheet; a switching processing unit that switches between permission and prohibition of movement of the pair of conveying members based on a sheet size associated with a sheet feed source of the sheet and the sheet size detected by the detection processing unit; A sheet conveying device comprising:

2. the switching processing unit permits movement of the pair of conveying members when a sheet size associated with a paper feed source of the sheet matches a sheet size of the sheet detected by the detection processing unit, and does not permit movement of the pair of conveying members when the sheet size does not match. The sheet transport device according to claim 1 .

3. the switching processing unit permits movement of the pair of conveying members when a sheet size associated with a paper feed source of the sheet is included in a sheet size group corresponding to the sheet size of the sheet detected by the detection processing unit, and does not permit movement of the pair of conveying members when the sheet size is not included in the sheet size group. The sheet transport device according to claim 1 .

4. a notification processing unit that notifies a user when the movement of the pair of conveying members is not permitted by the switching processing unit; The sheet transport device according to claim 1 .

5. A sheet conveying device according to any one of claims 1 to 4, an image forming unit that forms an image on the sheet conveyed by the sheet conveying device; An image forming apparatus comprising:

6. An operation control method executed by a sheet conveying device including: a pair of conveying members that are movable along a width direction perpendicular to a sheet conveying direction and that sandwich and convey the sheet; a sensor that detects a position in the width direction of the sheet conveyed by the pair of conveying members; and a movement control unit that controls movement of the pair of conveying members that are sandwiching the sheet along the width direction based on an amount of deviation between a detection position detected by the sensor and a reference position based on a sheet size associated with a paper feed source of the sheet, the operation control method comprising: a detection step of detecting a sheet size of the sheet; a switching step of switching whether or not the movement of the pair of conveying members is permitted based on a sheet size associated with a sheet feed source of the sheet and the sheet size detected in the detection step; The motion control method includes:

Images