Image forming apparatus and determination method

Abstract

To provide an image forming apparatus and a determination method that can determine a cause of paper jam that has been unable to be determined.SOLUTION: An image forming apparatus 100 comprises: conveying rollers; an image forming unit 3 that forms an image on a sheet conveyed by the conveying rollers; a detection processing unit 81 that detects paper jam in which the sheet conveyed by the conveying rollers jams during execution of image forming processing of forming an image on the sheet by using the image forming unit 3; and a determination processing unit 82 that, when the detection processing unit 81 detects the paper jam, determines a cause of the paper jam on the basis of a section where the paper jam occurs.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and a determination method. [Background technology]

[0002] An image forming apparatus such as a printer includes a sheet conveying unit and an image forming unit. The sheet conveying unit conveys a sheet. The image forming unit forms an image on the sheet conveyed by the sheet conveying unit.

[0003] In this type of image forming apparatus, a paper jam may occur in the sheet being conveyed by the sheet conveying unit during an image forming process in which an image is formed on the sheet using the image forming unit. In response to this, an image forming apparatus that determines the cause of the paper jam based on a scanned image of the sheet or the like is known as related technology. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-225081 Summary of the Invention [Problem to be solved by the invention]

[0005] When the image forming apparatus forms an image using an electrophotographic method, the paper jam may occur when the sheet onto which the toner image has been transferred wraps around a fixing member such as a fixing belt. Furthermore, in the image forming apparatus, the paper jam may occur when the sheet separates from the upstream transport roller before reaching the downstream transport roller of two transport rollers aligned in the sheet transport direction. However, the image forming apparatus according to the related art described above cannot determine the causes of these two paper jams.

[0006] An object of the present invention is to provide an image forming apparatus and a method for determining the cause of a paper jam, which has not been possible to determine until now. [Means for solving the problem]

[0007] According to one aspect of the present invention, an image forming apparatus includes a sheet conveying unit, an image forming unit, a detection processing unit, and a determination processing unit. The sheet conveying unit conveys a sheet. The image forming unit forms an image on the sheet conveyed by the sheet conveying unit. The detection processing unit detects a paper jam in the sheet conveyed by the sheet conveying unit during an image forming process in which the image is formed on the sheet using the image forming unit. When the detection processing unit detects the paper jam, the determination processing unit determines the cause of the paper jam based on the section in which the paper jam occurred.

[0008] A determination method according to another aspect of the present invention is executed by an image forming apparatus including a sheet conveying unit that conveys a sheet and an image forming unit that forms an image on the sheet conveyed by the sheet conveying unit, and includes a detection step and a determination step. In the detection step, a paper jam in the sheet conveyed by the sheet conveying unit is detected during an image forming process that forms an image on the sheet using the image forming unit. In the determination step, if the paper jam is detected in the detection step, the cause of the paper jam is determined based on the section in which the paper jam occurred. [Effects of the Invention]

[0009] According to the present invention, it is possible to determine the cause of a paper jam, which has not been possible to determine before. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2]FIG. 2 is a diagram showing the configuration of the image forming unit, the first conveying unit, and the second conveying unit of the image forming apparatus according to the embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the configuration of a post-processing section of the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing the system configuration of the image forming apparatus according to the embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart showing an example of an image forming operation control process executed by the image forming apparatus according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing an example of a cause determination process executed by the image forming apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[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 does not 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 Figures 1 to 4. Here, Figure 1 is a front view showing the appearance of the image forming apparatus 100. Also, Figure 2 is a cross-sectional view showing the configuration of the image forming section 3, the first conveying section 4, and the second conveying section 5. Also, Figure 3 is a cross-sectional view showing the configuration of the post-processing section 6.

[0013] Image forming apparatus 100 has a print function for forming an image on a sheet. Specifically, image forming apparatus 100 is a multifunction device that has multiple functions, such as a scan function, a fax function, and a copy function, in addition to the print function. Note that the present invention is applicable to image forming apparatuses such as printers, fax machines, and copy machines.

[0014] As shown in Figures 1 and 4, the image forming apparatus 100 includes an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a first conveying unit 4, a second conveying unit 5, a post-processing unit 6, an operation display unit 7, a memory unit 8, and a control unit 9.

[0015] The ADF 1 transports a document whose image is to be read by the image reading unit 2. The ADF 1 includes a document setting unit, a plurality of transport rollers, a document presser, and a paper discharge unit.

[0016] The image reading unit 2 realizes the scanning function. The image reading unit 2 includes a document table, a light source, multiple mirrors, an optical lens, and a CCD (Charge Coupled Device). The image reading unit 2 reads an image from a document transported by the ADF 1 and outputs image data including the read image. The image reading unit 2 also reads an image from a document placed on the document table and outputs image data including the read image.

[0017] The image forming unit 3 realizes the printing function. Specifically, the image forming unit 3 forms an image by electrophotography. As shown in FIG. 2, the image forming unit 3 includes a photosensitive drum 31, a charging roller 32, an optical scanning device 33, a developing device 34, a transfer roller 35, a cleaning device 36, a fixing unit 37, and a paper discharge tray 38. The image forming unit 3 forms an image based on image data output by the image reading unit 2. The image forming unit 3 also forms an image based on image data input from an external information processing device.

[0018] The charging roller 32 charges the surface of the photosensitive drum 31. The optical scanning device 33 irradiates the surface of the photosensitive drum 31 charged by the charging roller 32 with light based on image data. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 31.

[0019] The developing device 34 uses a developer containing toner to develop the electrostatic latent image formed on the surface of the photosensitive drum 31. A toner image is formed on the surface of the photosensitive drum 31 by the developing device 34.

[0020] The transfer roller 35 transfers the toner image formed on the surface of the photosensitive drum 31 onto a sheet transported by the first transport unit 4. The cleaning device 36 removes the toner remaining on the surface of the photosensitive drum 31 after the toner image has been transferred by the transfer roller 35.

[0021] The fixing unit 37 fixes the toner image transferred to the sheet by the transfer roller 35 onto the sheet. As shown in FIG. 2, the fixing unit 37 includes a fixing member 371 and a pressure roller 372. The fixing member 371 is formed in a belt or roller shape. The fixing member 371 is heated by a heater (not shown). The pressure roller 372 forms a fixing nip between itself and the fixing member 371. The sheet onto which the toner image has been transferred is heated and pressed as it passes through the fixing nip. As a result, the toner image transferred to the sheet is fixed to the sheet.

[0022] The sheet that has passed through the fixing unit 37 is discharged onto the discharge tray 38. In the image forming apparatus 100 of this embodiment, the second conveying unit 5 is attached to the discharge tray 38.

[0023] The first conveying section 4 conveys the sheet via the image forming section 3 to the paper discharge tray 38 or to the second conveying section 5 attached to the paper discharge tray 38. As shown in FIG. 2, the first conveying section 4 includes four paper feed units 40 (41 to 44), a sheet conveying path 45, and a plurality of conveying rollers 46. The first conveying section 4 also includes a plurality of sheet sensors 47 (see FIG. 4) corresponding to the plurality of conveying rollers 46.

[0024] Each paper feed unit 40 includes a cassette 401, a pickup roller 402, and a paper feed roller 403. Each cassette 401 holds sheets of various sizes. The sheets held in the cassette 401 include paper, coated paper, postcards, envelopes, and transparencies. Each pickup roller 402 transports the topmost sheet of the multiple sheets stored in the cassette 401 to the paper feed roller 403. The paper feed roller 403 transports the sheet transported by the pickup roller 402 to the sheet transport path 45.

[0025] The sheet transport path 45 is a passageway along which the sheets transported by the first transport unit 4 move. The sheet transport path 45 is formed by a pair of guide members provided inside a housing that houses the components of the image forming unit 3. The sheet transport path 45 extends upward from the lowest sheet feed unit 44 (see FIG. 2) of the four vertically aligned sheet feed units 40, passes through the image forming unit 3, and extends to the second transport unit 5. Of the four vertically aligned sheet feed units 40, the sheet feed units 41 to 43 above the sheet feed unit 44 communicate with the sheet transport path 45 above the sheet feed unit 44.

[0026] The plurality of transport rollers 46 are arranged side by side along the sheet transport path 45. Each of the transport rollers 46 transports the sheet in a direction toward the second transport unit 5.

[0027] The sheet sensors 47 are provided at positions corresponding to the transport rollers 46 in the sheet transport path 45. The sheet sensors 47 detect sheets passing through the positions of the transport rollers 46 in the sheet transport path 45. For example, the sheet sensors 47 are reflective or transmissive optical sensors.

[0028] The second conveying section 5 conveys the sheet conveyed from the first conveying section 4 to the post-processing section 6. The second conveying section 5 is an optional unit configured to be detachable from the paper discharge tray 38. As shown in FIG. 2, the second conveying section 5 includes a sheet conveying path 51 and a plurality of conveying rollers 52. The second conveying section 5 also includes a plurality of sheet sensors 53 (see FIG. 4) corresponding to the plurality of conveying rollers 52.

[0029] The sheet transport path 51 is a path along which the sheet transported by the second transport section 5 moves. The sheet transport path 51 extends from the first transport section 4 to the post-processing section 6.

[0030] The plurality of transport rollers 52 are arranged side by side along the sheet transport path 51. Each of the transport rollers 52 transports the sheet in a direction toward the post-processing section 6.

[0031] The sheet sensors 53 are provided at positions corresponding to the transport rollers 52 in the sheet transport path 51. The sheet sensors 53 detect sheets passing through the positions of the transport rollers 52 in the sheet transport path 51. For example, the sheet sensors 53 are reflective or transmissive optical sensors.

[0032] In the image forming apparatus 100, the first conveying section 4 may be connected to the post-processing section 6 without the second conveying section 5. In this case, the image forming apparatus 100 does not need to include the second conveying section 5.

[0033] The post-processing unit 6 performs post-processing such as perforation (punching) and stapling on sheets on which images have been formed and which are conveyed from the second conveying unit 5. The perforation is a process of punching holes in the sheets. The stapling is a process of stapling multiple sheets stacked on a stack tray 671 (see FIG. 3). The post-processing unit 6 is an optional unit configured to be connectable to the second conveying unit 5. As shown in FIG. 3, the post-processing unit 6 includes a first sheet conveying path 61, multiple first conveying rollers 62, a second sheet conveying path 63, multiple second conveying rollers 64, a switching member 65, a perforation unit 66, a staple unit 67, a first paper output tray 68, and a second paper output tray 69. The post-processing unit 6 also includes multiple first sheet sensors 70 (see FIG. 4) corresponding to the multiple first conveying rollers 62 and multiple second sheet sensors 71 (see FIG. 4) corresponding to the multiple second conveying rollers 64.

[0034] The first sheet transport path 61 is a path along which sheets move, formed inside the post-processing section 6. The first sheet transport path 61 extends from the second transport section 5 to the first discharge tray 68.

[0035] The plurality of first transport rollers 62 are arranged side by side along the first sheet transport path 61. Each of the first transport rollers 62 transports a sheet in a direction toward the first paper discharge tray 68.

[0036] The second sheet transport path 63 branches off from the first sheet transport path 61 midway and extends to a second sheet discharge tray 69 .

[0037] The plurality of second transport rollers 64 are arranged side by side along the second sheet transport path 63. Each of the second transport rollers 64 transports a sheet in a direction toward the second discharge tray 69.

[0038] The switching member 65 is provided at a branching portion of the first sheet transport path 61 that branches off to the second sheet transport path 63, and switches the destination of the sheet to either the first discharge tray 68 or the second discharge tray 69. The switching member 65 switches the destination of the sheet by being swung by a drive unit (not shown), such as a motor or a solenoid. In the image forming apparatus 100, when the stapling process is to be performed on the sheet, the control unit 9 operates the switching member 65 to set the destination of the sheet to the first discharge tray 68. On the other hand, when the stapling process is not to be performed on the sheet, the control unit 9 operates the switching member 65 to set the destination of the sheet to the second discharge tray 69.

[0039] The punching unit 66 performs the punching process.

[0040] The stapler 67 performs the stapling process.

[0041] The first sheet sensors 70 are provided at the positions of the first transport rollers 62 in the first sheet transport path 61. The first sheet sensors 70 detect sheets passing through the positions of the first transport rollers 62 in the first sheet transport path 61. For example, the first sheet sensors 70 are reflective or transmissive optical sensors.

[0042] The second sheet sensors 71 are provided at positions corresponding to the second transport rollers 64 in the second sheet transport path 63. The second sheet sensors 71 detect sheets passing through the positions corresponding to the second transport rollers 64 in the second sheet transport path 63. For example, the second sheet sensors 71 are reflective or transmissive optical sensors.

[0043] The operation display unit 7 is a user interface of the image forming apparatus 100. The operation display unit 7 has a display unit such as a liquid crystal display that displays various information in response to control instructions from the control unit 9, and an operation unit such as operation keys or a touch panel that inputs various information to the control unit 9 in response to user operations.

[0044] The storage unit 8 is a non-volatile storage device, such as a flash memory.

[0045] The control unit 9 performs overall control of the image forming apparatus 100. As shown in FIG. 4, the control unit 9 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various types of arithmetic processing. The ROM 12 is a non-volatile storage device that stores in advance information such as control programs for causing the CPU 11 to execute various types of processing. The RAM 13 is a volatile or non-volatile storage device that is used as a temporary storage memory (work area) for the various types of processing executed by the CPU 11. In the control unit 9, the CPU 11 executes the various control programs that are pre-stored in the ROM 12. In this way, the control unit 9 performs overall control of the image forming apparatus 100.

[0046] The control unit 9 may be a control unit provided separately from a main control unit that performs overall control of the image forming apparatus 100. The control unit 9 may also be configured with an electronic circuit such as an integrated circuit (ASIC).

[0047] In the image forming apparatus 100, a sheet is transported in a transport direction D1 (see FIG. 2 ) toward a first discharge tray 68 or a second discharge tray 69 by a plurality of transport rollers 46 of the first transport unit 4, a plurality of transport rollers 52 of the second transport unit 5, a plurality of first transport rollers 62 of the post-processing unit 6, and a plurality of second transport rollers 64 of the post-processing unit 6. The image forming unit 3 forms an image on the sheet transported by the plurality of transport rollers 46, the plurality of transport rollers 52, the plurality of first transport rollers 62, and the plurality of second transport rollers 64. The plurality of transport rollers 46, the plurality of transport rollers 52, the plurality of first transport rollers 62, and the plurality of second transport rollers 64 are an example of a sheet transport unit of the present invention. Hereinafter, the transport rollers 46, the transport rollers 52, the first transport rollers 62, and the second transport rollers 64 may be collectively referred to as "transport rollers X." Furthermore, the sheet sensor 47, the sheet sensor 53, the first sheet sensor 70, and the second sheet sensor 71 may be collectively referred to as "sheet sensor Y."

[0048] Incidentally, in the image forming apparatus 100, during the execution of an image forming process in which an image is formed on a sheet using the image forming unit 3, a paper jam may occur in which the sheet being conveyed by the conveyance roller X gets stuck. In response to this, an image forming apparatus that determines the cause of the paper jam based on a scanned image of the sheet or the like is known as related art.

[0049] Here, in the image forming apparatus 100, the paper jam may occur when the sheet onto which the toner image has been transferred wraps around the fixing member 371. Also, in the image forming apparatus 100, the paper jam may occur when the sheet separates from the upstream transport roller X before reaching the downstream transport roller X of two transport rollers X aligned along the transport direction D1. However, the image forming apparatus according to the related art described above cannot determine the causes of these two paper jams.

[0050] In contrast to this, the image forming apparatus 100 according to the embodiment of the present invention is able to determine the cause of the paper jam, which has not been possible to determine before, as will be described below.

[0051] [Configuration of control unit 9] Next, the configuration of the control unit 9 will be described with reference to FIG.

[0052] As shown in FIG. 4, the control unit 9 includes a detection processing unit 81, a determination processing unit 82, a switching processing unit 83, and a notification processing unit 84.

[0053] Specifically, an image forming operation control program for causing the CPU 11 to function as each of the above-mentioned processing sections is stored in advance in the ROM 12 of the control section 9. The CPU 11 then executes the image forming operation control program stored in the ROM 12 to function as each of the above-mentioned processing sections.

[0054] The image forming operation control program may be recorded on a computer-readable recording medium such as a CD, a DVD, or a flash memory, and may be read from the recording medium and stored in a storage device such as the memory unit 8. Some or all of the processing units included in the control unit 9 may be configured with electronic circuits. The image forming operation control program may also be a program for causing a plurality of processors to function as each processing unit included in the control unit 9.

[0055] The detection processing unit 81 detects the paper jam that occurs when a sheet being conveyed by the conveyance roller X gets jammed during the image forming process in which an image is formed on a sheet using the image forming unit 3.

[0056] For example, the detection processing unit 81 detects the paper jam when a sheet is not detected by the next sheet sensor Y between the time when a sheet is detected by one of the multiple sheet sensors Y lined up along the sheet transport path in the image forming process and the time when a reference time corresponding to that sheet sensor Y has elapsed.

[0057] The transport path is determined by the execution conditions of the image forming process. For example, when the paper feed source is set to paper feed unit 42 and the staple function for executing the stapling process is enabled, the transport path starts from paper feed unit 42 and ends at first paper output tray 68. When the paper feed source is set to paper feed unit 44 and the staple function is disabled, the transport path starts from paper feed unit 44 and ends at second paper output tray 69.

[0058] When the detection processing unit 81 detects a paper jam, the determination processing unit 82 determines the cause of the paper jam based on the section in which the paper jam occurred.

[0059] For example, the causes of the paper jam that can be determined by the determination processing unit 82 include a first cause, a second cause, a third cause, and a fourth cause.

[0060] The first cause is that the width of the margin area set at both ends of the sheet in the width direction perpendicular to the conveyance direction D1 is insufficient. If the width of the margin area is too narrow, the sheet with the toner image transferred thereon will wrap around the fixing member 371, causing the paper jam.

[0061] The second cause is that the size of the sheet in the conveying direction D1 is insufficient. If the size of the sheet in the conveying direction D1 is too small, the sheet will separate from the upstream conveying roller X before reaching the downstream conveying roller X of the two conveying rollers X lined up in the conveying direction D1 (the sheet will get stuck between the two conveying rollers X), causing the paper jam.

[0062] The third cause is that the type of sheet is not suitable for transport by the transport roller X. For example, if the sheet is made of a slippery material such as resin, or if the sheet is coated, the transport roller X will slip, causing the paper jam. Also, if the sheet has perforations, part of the sheet may separate during transport, and the separated part may impede the transport of the following sheet, causing the paper jam.

[0063] The fourth cause is a malfunction of the transport roller X located in the section where the paper jam occurred. Note that "the transport roller X is malfunctioning" means that the transport roller X has an initial defect or its function of transporting sheets is impaired due to deterioration over time.

[0064] For example, when the detection processing unit 81 detects the paper jam, the judgment processing unit 82 judges that the section from the position of the sheet sensor Y that last detected the sheet to the position of the next sheet sensor Y is the occurrence section.

[0065] Furthermore, when the occurrence section includes the fixing unit 37 and the width of the margin area (the distance in the width direction) is less than a predetermined reference value, the determination processing unit 82 determines that the cause of the paper jam is the first cause. For example, the reference value is predetermined for each size in the width direction of the sheet on which an image is formed.

[0066] Furthermore, if the size of the sheet in the conveying direction D1 is less than the reference size corresponding to the section in which the jam occurred, the determination processor 82 determines that the cause of the paper jam is the second cause. The reference size is predetermined for each section defined by two sheet sensors Y aligned along the conveying direction D1. For example, the reference size corresponding to a certain section is 1.1 times the distance of the section in the conveying direction D1.

[0067] Furthermore, when the cause of the paper jam is neither the first cause nor the second cause, but the type of sheet corresponds to one of the predetermined specific types, the determination processing unit 82 determines that the cause of the paper jam is the third cause. For example, the specific types include coated paper, OHP sheets, and sheets with perforations.

[0068] Furthermore, when the cause of the paper jam is not the first cause, the second cause, or the third cause, the determination processing unit 82 determines that the cause of the paper jam is the fourth cause.

[0069] The determination processing unit 82 may specify the width of the margin area, the size of the sheet, and the type of the sheet based on the settings on a setting screen that sets the execution conditions of the image forming process. The image forming apparatus 100 may also include an imaging unit that captures an image of the sheet being transported by the transport roller X. In this case, the determination processing unit 82 may determine the size and type of the sheet based on the image capture result by the imaging unit.

[0070] The determination processing unit 82 may determine the cause of the paper jam using a method different from the methods described above. The causes of the paper jam that can be determined by the determination processing unit 82 may include causes other than the first cause, the second cause, the third cause, and the fourth cause.

[0071] When the judgment processing unit 82 judges that the cause of the paper jam is the fourth cause, and when there is a first transport path that can transport the sheet without changing the execution conditions of the image forming process and without passing through the transport roller X that has been judged to be faulty, the switching processing unit 83 switches the transport path of the sheet in the image forming process from the second transport path that passes through the occurrence section to the first transport path.

[0072] For example, suppose that the paper feed source is set to paper feed unit 44 and the image forming process is performed, and the paper jam occurs in the section between the most upstream transport roller X on the transport path and the next transport roller X. In other words, suppose that it is determined that the most upstream transport roller X on the transport path is faulty. In this case, if there is another cassette 401 that stores the same sheets as those stored in cassette 401 of paper feed unit 44, the switching processing unit 83 switches the paper feed source to paper feed unit 40 that includes the other cassette 401, thereby switching the transport path from the second transport path to the first transport path. Furthermore, if there is no other cassette 401 that stores the same sheets as those stored in cassette 401 of paper feed unit 44, the switching processing unit 83 does not switch the transport path.

[0073] Furthermore, when the staple function is enabled and the image forming process is executed, it is assumed that the paper jam occurs in a section of the first sheet conveying path 61 downstream of the switching member 65 in the conveying direction D1. In this case, unless the execution conditions of the image forming process are changed (the staple function is disabled), the section where the jam occurred cannot be avoided. Therefore, the switching processing unit 83 does not switch the conveying path.

[0074] In addition, when the judgment processing unit 82 judges that the cause of the paper jam is the second cause, and there is a third transport path that can transport the sheet without changing the execution conditions of the image forming process and without passing through the occurrence section, the switching processing unit 83 may switch the transport path from the second transport path to the third transport path.

[0075] The notification processing unit 84 notifies the result of the determination made by the determination processing unit 82 .

[0076] For example, when the judgment processing unit 82 determines that the cause of the paper jam is the first cause, the notification processing unit 84 causes the operation display unit 7 to display a message to that effect and to indicate that the paper jam can be avoided by widening the width of the margin area.

[0077] In addition, when the judgment processing unit 82 determines that the cause of the paper jam is the second cause, the notification processing unit 84 displays a message on the operation display unit 7 indicating this and that the paper jam can be avoided by increasing the size of the sheet in the conveying direction D1.

[0078] In addition, when the judgment processing unit 82 determines that the cause of the paper jam is the third cause, the notification processing unit 84 displays a message on the operation display unit 7 indicating this and that the paper jam can be avoided by changing the type of sheet.

[0079] Furthermore, when the determination processing unit 82 determines that the cause of the paper jam is the fourth cause, the notification processing unit 84 causes the operation display unit 7 to display a message indicating that. Furthermore, when the occurrence section can be avoided by changing the execution conditions, the notification processing unit 84 causes the operation display unit 7 to display a message indicating that.

[0080] Hereinafter, an example of the procedure of each process executed by the control unit 9 and the determination method of the present invention will be described.

[0081] [Image formation operation control processing] 5, an example of the procedure of the image forming operation control process executed by the control unit 9 in the image forming apparatus 100 will be described. Here, steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 9. The image forming operation control process is executed when an instruction to execute the image forming process is input.

[0082] <Step S11> First, in step S11, the control unit 9 starts the image forming process.

[0083] <Step S12> In step S12, the control unit 9 determines whether or not the image forming process has been completed.

[0084] Here, when the control unit 9 determines that the image forming process has ended (Yes in S12), it ends the image forming operation control process. On the other hand, when the image forming process has not ended (No in S12), the control unit 9 shifts the process to step S13.

[0085] <Step S13> In step S13, the control unit 9 determines whether or not the paper jam has been detected. The process of step S13 is an example of a detection step of the present invention, and is executed by the detection processing unit 81 of the control unit 9.

[0086] Specifically, the control unit 9 detects the paper jam when a sheet is not detected by the next sheet sensor Y between the time when a sheet is detected by one of the multiple sheet sensors Y lined up along the transport path and the time when the reference time corresponding to that sheet sensor Y has elapsed.

[0087] Here, if the control unit 9 determines that the paper jam has been detected (Yes in S13), it shifts the process to step S14. On the other hand, if the control unit 9 does not detect the paper jam (No in S13), it shifts the process to step S12.

[0088] <Step S14> In step S14, the control unit 9 stops the image forming process.

[0089] <Step S15> In step S15, the control unit 9 notifies the user that a paper jam has occurred.

[0090] For example, the control unit 9 causes the operation and display unit 7 to display a message indicating that a paper jam has occurred together with an image showing the section where the paper jam has occurred. The control unit 9 also causes the operation and display unit 7 to display an image or video showing the procedure for clearing the paper jam.

[0091] <Step S16> In step S16, the control unit 9 determines whether the paper jam has been resolved.

[0092] For example, the control unit 9 determines that the paper jam has been cleared when it detects that a cover member corresponding to the section where the paper jam occurred has been closed, out of one or more cover members that are openably and closably provided on the housing of the image forming apparatus 100. The fact that the cover member has been closed may be detected by a sensor provided corresponding to the cover member.

[0093] Here, if the control unit 9 determines that the paper jam has been cleared (Yes in S16), it shifts the process to step S17. On the other hand, if the paper jam has not been cleared (No in S16), the control unit 9 waits for the paper jam to be cleared in step S16.

[0094] <Step S17> In step S17, the control unit 9 executes a cause determination process, which will be described later.

[0095] <Step S18> In step S18, the control unit 9 determines whether or not a user operation to instruct the suspension of the image forming process has been accepted during the execution of the cause determination process.

[0096] Here, if the control unit 9 determines that a user operation to instruct the image forming process to be stopped has been accepted (Yes in S18), it terminates the image forming operation control process. On the other hand, if a user operation to instruct the image forming process to be stopped has not been accepted (No in S18), the control unit 9 shifts the process to step S19.

[0097] <Step S19> In step S19, the control unit 9 restarts the image forming process.

[0098] [Cause determination process] Next, with reference to FIG. 6, an example of the procedure of the cause determination process executed in step S17 of the image forming operation control process will be described.

[0099] <Step S21> First, in step S21, the control unit 9 determines the cause of the paper jam. The process of step S21 is an example of a determination step of the present invention, and is executed by the determination processing unit 82 of the control unit 9.

[0100] Specifically, the control unit 9 determines that the section from the arrangement position of the sheet sensor Y that last detected the sheet to the arrangement position of the next sheet sensor Y is the occurrence section.

[0101] Furthermore, when the occurrence section includes the fixing unit 37 and the width of the margin area is less than the reference value, the control unit 9 determines that the cause of the paper jam is the first cause.

[0102] Furthermore, when the size of the sheet in the transport direction D1 is less than the reference size corresponding to the occurrence section, the control unit 9 determines that the cause of the paper jam is the second cause.

[0103] Furthermore, when the cause of the paper jam is neither the first cause nor the second cause, and the type of sheet corresponds to one of the specific types, the control unit 9 determines that the cause of the paper jam is the third cause.

[0104] Furthermore, when the cause of the paper jam is not the first cause, the second cause, or the third cause, the control unit 9 determines that the cause of the paper jam is the fourth cause.

[0105] <Step S22> In step S22, the control unit 9 branches the process depending on the result of the process in step S21. Specifically, if the process in step S21 determines that the cause of the paper jam is the fourth cause (Yes in S22), the control unit 9 shifts the process to step S23. On the other hand, if the process in step S21 does not determine that the cause of the paper jam is the fourth cause (No in S22), the control unit 9 shifts the process to step S31.

[0106] <Step S23> In step S23, the control unit 9 determines whether or not there is a first transport path that can transport the sheet without changing the execution conditions of the image forming process and without passing through the transport roller X that has been determined to be faulty.

[0107] Here, if the control unit 9 determines that the first transport path exists (Yes in S23), it shifts the process to step S24. On the other hand, if the first transport path does not exist (No in S23), it shifts the process to step S25.

[0108] <Step S24> In step S24, the control unit 9 switches the transport path from the second transport path to the first transport path. The process of step S24 is executed by the switching processing unit 83 of the control unit 9. This makes it possible to automatically switch the transport path to a path that bypasses the occurrence section.

[0109] <Step S25> In step S25, the control unit 9 executes a fourth notification process to notify the user that the cause of the paper jam has been determined to be the fourth cause. The process of step S25 is executed by the notification processing unit 84 of the control unit 9.

[0110] Specifically, in the fourth notification process, a message indicating that the cause of the paper jam has been determined to be the fourth cause is displayed on the operation display unit 7. Also, in the fourth notification process, if the occurrence section can be avoided by changing the execution conditions, a message indicating this is displayed on the operation display unit 7. Also, in the fourth notification process, a selection screen used for a selection operation to select whether or not to cancel the image forming process is displayed on the operation display unit 7, and the selection operation by the user is accepted. Note that, if the occurrence section can be avoided by changing the execution conditions, whether or not to change the execution conditions may be selected by a user operation.

[0111] <Step S26> In step S26, the control unit 9 determines whether or not the selection operation has been accepted on the selection screen.

[0112] Here, if the control unit 9 determines that the selection operation has been accepted (Yes in S26), it ends the cause determination process. On the other hand, if the selection operation has not been accepted (No in S26), the control unit 9 waits for acceptance of the selection operation in step S26.

[0113] <Step S31> In step S31, the control unit 9 branches the process depending on the result of the process in step S21. Specifically, if the process in step S21 determines that the cause of the paper jam is the second cause (Yes in S31), the control unit 9 shifts the process to step S32. On the other hand, if the process in step S21 does not determine that the cause of the paper jam is the second cause (No in S31), the control unit 9 shifts the process to step S41.

[0114] <Step S32> In step S32, the control unit 9 executes a second notification process to notify the user that the cause of the paper jam has been determined to be the second cause. The process of step S32 is executed by the notification processing unit 84 of the control unit 9.

[0115] Specifically, in the second notification process, a message indicating that the cause of the paper jam has been determined to be the second cause and that the paper jam can be avoided by increasing the size of the sheet in the conveying direction D1 is displayed on the operation and display unit 7. Also, in the second notification process, the selection screen is displayed on the operation and display unit 7, and the selection operation by the user is accepted.

[0116] <Step S33> In step S33, the control unit 9 determines whether or not the selection operation has been accepted on the selection screen.

[0117] Here, if the control unit 9 determines that the selection operation has been accepted (Yes in S33), it ends the cause determination process. On the other hand, if the selection operation has not been accepted (No in S33), the control unit 9 waits for acceptance of the selection operation in step S33.

[0118] <Step S41> In step S41, the control unit 9 branches the process depending on the result of the process in step S21. Specifically, if the process in step S21 determines that the cause of the paper jam is the third cause (Yes in S41), the control unit 9 shifts the process to step S42. On the other hand, if the process in step S21 does not determine that the cause of the paper jam is the third cause (No in S41), the control unit 9 shifts the process to step S51.

[0119] <Step S42> In step S42, the control unit 9 executes a third notification process to notify the user that the cause of the paper jam has been determined to be the third cause. The process of step S42 is executed by the notification processing unit 84 of the control unit 9.

[0120] Specifically, in the third notification process, a message indicating that the cause of the paper jam has been determined to be the third cause and that the paper jam can be avoided by changing the type of sheet is displayed on the operation and display unit 7. Also, in the third notification process, the selection screen is displayed on the operation and display unit 7, and the selection operation by the user is accepted.

[0121] <Step S43> In step S43, the control unit 9 determines whether or not the selection operation has been accepted on the selection screen.

[0122] Here, if the control unit 9 determines that the selection operation has been accepted (Yes in S43), it ends the cause determination process. On the other hand, if the selection operation has not been accepted (No in S43), the control unit 9 waits for acceptance of the selection operation in step S43.

[0123] <Step S51> In step S51, the control unit 9 executes a first notification process to notify the user that the cause of the paper jam has been determined to be the first cause. The process of step S51 is executed by the notification processing unit 84 of the control unit 9.

[0124] Specifically, in the first notification process, a message indicating that the cause of the paper jam has been determined to be the first cause and that the occurrence of the paper jam can be avoided by widening the width of the margin area is displayed on the operation and display unit 7. Also, in the first notification process, the selection screen is displayed on the operation and display unit 7, and the selection operation by the user is accepted.

[0125] <Step S52> In step S52, the control unit 9 determines whether or not the selection operation has been accepted on the selection screen.

[0126] Here, if the control unit 9 determines that the selection operation has been accepted (Yes in S52), it ends the cause determination process. On the other hand, if the selection operation has not been accepted (No in S52), the control unit 9 waits for acceptance of the selection operation in step S52.

[0127] In this way, when the image forming apparatus 100 detects a paper jam, the cause of the paper jam is determined based on the section in which the paper jam occurred. By taking the width of the margin area into consideration, it is possible to determine whether the cause of the paper jam is the first cause. Furthermore, by taking the size of the sheet in the conveying direction D1 into consideration, it is possible to determine whether the cause of the paper jam is the second cause. Therefore, it is possible to determine the cause of the paper jam, which could not be determined by the image forming apparatus according to the related art described above.

[0128] The determination processing unit 82 may be provided in an information processing device such as a server connected to the image forming apparatus 100 so as to be able to communicate with the image forming apparatus 100.

[0129] [Notes on the Invention] The following is a summary 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.

[0130] <Appendix 1> An image forming apparatus comprising: a sheet conveying unit that conveys a sheet; an image forming unit that forms an image on the sheet conveyed by the sheet conveying unit; a detection processing unit that detects a paper jam in the sheet conveyed by the sheet conveying unit while an image forming process is being executed to form an image on the sheet using the image forming unit; and a judgment processing unit that, when the detection processing unit detects the paper jam, determines the cause of the paper jam based on the section in which the paper jam occurs.

[0131] <Appendix 2> The image forming device described in Appendix 1, wherein the image forming unit includes a fixing unit that fixes the toner image transferred to the sheet to the sheet, and the cause of the paper jam includes a first cause that the width of the margin area set at both ends of the sheet in a width direction perpendicular to the sheet conveying direction is insufficient, and the judgment processing unit judges that the cause of the paper jam is the first cause when the occurrence section includes the fixing unit and the width of the margin area is less than a predetermined reference value.

[0132] <Appendix 3> The image forming apparatus of claim 1 or 2, wherein the cause of the paper jam includes a second cause in which the size of the sheet in the transport direction is insufficient, and the judgment processing unit judges that the cause of the paper jam is the second cause when the size of the sheet in the transport direction is less than a reference size corresponding to the occurrence section.

[0133] <Appendix 4> The image forming apparatus of Appendix 2, wherein the causes of the paper jam include a second cause that the size of the sheet in the transport direction is insufficient and a third cause that the type of sheet is not suitable for transport by the sheet transport unit, and the judgment processing unit judges that the cause of the paper jam is the second cause when the size of the sheet in the transport direction is less than a reference size corresponding to the occurrence section, and judges that the cause of the paper jam is the third cause when the cause of the paper jam is not the first cause or the second cause but the type of the sheet corresponds to one of predetermined specific types.

[0134] <Appendix 5> The image forming apparatus of Appendix 4, wherein the cause of the paper jam includes a fourth cause, which is a failure of the sheet transport unit located in the occurrence section, and the judgment processing unit judges that the cause of the paper jam is the fourth cause if the cause is not the first cause, the second cause, or the third cause.

[0135] <Appendix 6> An image forming apparatus as described in Appendix 5, further comprising a switching processing unit that switches the sheet transport path in the image forming process from a second transport path that passes through the occurrence section to the first transport path when the judgment processing unit determines that the cause of the paper jam is the fourth cause and when there is a first transport path that can transport the sheet without changing the execution conditions of the image forming process and without passing through the sheet transport unit that has been determined to be faulty.

[0136] <Appendix 7> 7. The image forming apparatus according to any one of claims 1 to 6, further comprising a notification processing unit that notifies a result of the determination by the determination processing unit.

[0137] <Appendix 8> A determination method executed in an image forming device equipped with a sheet transport unit that transports a sheet and an image forming unit that forms an image on the sheet transported by the sheet transport unit, the determination method including: a detection step that detects a paper jam in the sheet transported by the sheet transport unit during execution of an image formation process that forms an image on the sheet using the image forming unit; and a determination step that, when the paper jam is detected by the detection step, determines the cause of the paper jam based on the section in which the paper jam occurred. [Explanation of symbols]

[0138] 1 ADF 2 Image reading unit 3 Image forming unit 4 First conveyor section 5 Second conveying section 6 Post-processing section 7 Operation display section 8 Memory section 9 Control Unit 31 Photosensitive drum 32 Charging roller 33 Optical scanning device 34 Developing device 35 Transfer roller 36 Cleaning device 37 Fixing section 38 Paper output tray 40 Paper feed unit 45 Sheet transport path 46 Transport roller 47 Sheet Sensor 51 Sheet transport path 52 Transport roller 53 Sheet Sensor 61 First sheet transport path 62 First conveyor roller 63 Second sheet transport path 64 Second conveyor roller 65 Switching member 66 Perforation 67 Staple section 68 First output tray 69 Second output tray 70 First seat sensor 71 Second seat sensor 81 Detection processing unit 82 Judgment processing unit 83 Switching processing section 84 Notification processing section 100 Image forming device

Claims

1. a sheet conveying unit that conveys a sheet; an image forming unit that forms an image on the sheet conveyed by the sheet conveying unit; a detection processing unit that detects a paper jam in the sheet being conveyed by the sheet conveying unit during an image forming process in which an image is formed on the sheet using the image forming unit; a determination processing unit that, when the paper jam is detected by the detection processing unit, determines the cause of the paper jam based on the section in which the paper jam occurs; An image forming apparatus comprising:

2. the image forming unit includes a fixing unit that fixes the toner image transferred onto the sheet, The causes of the paper jam include a first cause that the width of margin areas set at both ends of the sheet in a width direction perpendicular to the sheet conveyance direction is insufficient, the determination processing unit determines that the cause of the paper jam is the first cause when the occurrence section includes the fixing section and the width of the margin area is less than a predetermined reference value; The image forming apparatus according to claim 1 .

3. The causes of the paper jam include a second cause that the size of the sheet in the sheet conveyance direction is insufficient, the determination processing unit determines that the cause of the paper jam is the second cause when the size of the sheet in the transport direction is less than a reference size corresponding to the occurrence section. The image forming apparatus according to claim 1 .

4. The causes of the paper jam include a second cause that the size of the sheet in the conveying direction is insufficient, and a third cause that the type of the sheet is not suitable for conveyance by the sheet conveying unit, the determination processing unit determines that the cause of the paper jam is the second cause when the size of the sheet in the transport direction is less than a reference size corresponding to the occurrence section, and determines that the cause of the paper jam is the third cause when the cause of the paper jam is neither the first cause nor the second cause and the type of the sheet corresponds to any of predetermined specific types. The image forming apparatus according to claim 2 .

5. The causes of the paper jam include a fourth cause in which the sheet conveying unit present in the occurrence section is broken, the determination processing unit determines that the cause of the paper jam is the fourth cause when the cause of the paper jam is not the first cause, the second cause, or the third cause; The image forming apparatus according to claim 4 .

6. a switching processing unit that switches the sheet transport path in the image forming process from a second transport path that passes through the section where the paper jam occurred to the first transport path when the determination processing unit determines that the cause of the paper jam is the fourth cause and when there is a first transport path that can transport the sheet without changing the execution conditions of the image forming process and without passing through the sheet transport unit that has been determined to be out of order; The image forming apparatus according to claim 5 .

7. a notification processing unit that notifies a result of the determination by the determination processing unit; 7. The image forming apparatus according to claim 1.

8. A determination method executed in an image forming apparatus including a sheet conveying unit that conveys a sheet and an image forming unit that forms an image on the sheet conveyed by the sheet conveying unit, a detection step of detecting a paper jam in the sheet being conveyed by the sheet conveying unit during execution of an image forming process in which an image is formed on the sheet using the image forming unit; a determining step of determining a cause of the paper jam based on the section in which the paper jam occurred when the paper jam is detected by the detecting step; A determination method including:

Images