Image forming apparatus, notification method

Abstract

To provide an image forming apparatus and a notification method capable of notifying information regarding abnormal locations on a conveyor belt. [Solution] The image forming apparatus comprises an imaging unit 5 that images a conveyor belt on which markers are provided at predetermined intervals along the circumferential direction; a rotation processing unit 61 that rotates the conveyor belt at least once and stops it; a first detection processing unit 62 that detects abnormal locations on the conveyor belt while the conveyor belt is rotating; a first count processing unit 63 that counts the number of markers that pass through the imaging position by the imaging unit 5 from the time the first detection processing unit 62 detects the abnormal location until the conveyor belt stops; and a notification processing unit 66 that notifies the detection of the abnormal location and the count result by the first count processing unit 63 when an abnormal location is detected.

Description

Technical Field

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

Background Art

[0002] An inkjet type image forming apparatus including a conveyance belt for conveying a sheet and an ink ejection unit such as a recording head for ejecting ink toward the sheet conveyed by the conveyance belt is known. Further, an image forming apparatus capable of detecting dirt on the conveyance belt using an optical sensor is known as a related art (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when there are abnormal portions such as ink stains and scratches on the conveyance belt, it is desirable to clean or replace the conveyance belt. However, in the image forming apparatus according to the above related art, information regarding the abnormal portion is not notified to the user. Therefore, it is difficult for the user to clean or replace the conveyance belt.

[0005] An object of the present invention is to provide an image forming apparatus and a notification method capable of notifying information regarding an abnormal portion on a conveyance belt.

Means for Solving the Problems

[0006] An image forming apparatus according to one aspect of the present invention comprises a conveyor belt, an ink ejection unit, a plurality of markers, an imaging unit, a rotation processing unit, a detection processing unit, a counting processing unit, and a notification processing unit. The conveyor belt conveys a sheet. The ink ejection unit ejects ink toward the sheet being conveyed by the conveyor belt. The plurality of markers are provided on the conveyor belt at predetermined intervals along the circumferential direction of the conveyor belt. The imaging unit images the conveyor belt. The rotation processing unit rotates the conveyor belt at least once and stops it. The detection processing unit uses the imaging unit to detect abnormal locations on the conveyor belt while the conveyor belt is being rotated by the rotation processing unit. The counting processing unit counts the number of markers that pass through the imaging position by the imaging unit between the time of detection of the abnormal location by the detection processing unit and a predetermined reference time. When the detection processing unit detects an abnormal location, the notification processing unit notifies the detection of the abnormal location and the count result by the counting processing unit after the conveyor belt has stopped.

[0007] A notification method according to another aspect of the present invention is performed in an image forming apparatus comprising: a conveyor belt for conveying a sheet; an ink discharge unit for discharging ink toward the sheet being conveyed by the conveyor belt; a plurality of markers provided on the conveyor belt at predetermined intervals along the circumferential direction of the conveyor belt; and an imaging unit for imaging the conveyor belt, and includes a rotation step, a detection step, a count step, and a notification step. In the rotation step, the conveyor belt is rotated at least once and stopped. In the detection step, the imaging unit is used to detect an abnormal location on the conveyor belt while the conveyor belt is rotating in the rotation step. In the count step, the number of markers passing through the imaging position by the imaging unit between the time of detection of the abnormal location in the detection step and a predetermined reference time is counted. In the notification step, if the abnormal location is detected in the detection step, the detection of the abnormal location and the count result from the count step are notified after the conveyor belt has stopped. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide information regarding abnormal locations in a conveyor belt. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing the system configuration of an image forming apparatus according to the first embodiment of the present invention. [Figure 2] Figure 2 is a front view showing the external configuration of an image forming apparatus according to the first embodiment of the present invention. [Figure 3] Figure 3 is a front view showing the configuration of the image forming section, sheet transport section, and line sensor of an image forming apparatus according to the first embodiment of the present invention. [Figure 4] Figure 4 is a plan view showing the configuration of the image forming section, sheet transport section, and line sensor of an image forming apparatus according to the first embodiment of the present invention. [Figure 5] Figure 5 shows the configuration of the conveyor belt of an image forming apparatus according to the first embodiment of the present invention. [Figure 6] Figure 6 is a flowchart showing an example of a first abnormality notification process performed in an image forming apparatus according to the first embodiment of the present invention. [Figure 7] Figure 7 is a flowchart showing an example of an anomaly detection process performed in an image forming apparatus according to the first embodiment of the present invention. [Figure 8] Figure 8 is a block diagram showing the system configuration of an image forming apparatus according to a second embodiment of the present invention. [Figure 9] Figure 9 is a flowchart showing an example of a second abnormality notification process performed in an image forming apparatus according to a second embodiment of the present invention. [Figure 10] Figure 10 is a block diagram showing the system configuration of an image forming apparatus according to a third embodiment of the present invention. [Figure 11] Figure 11 is a front view showing the external configuration of an image forming apparatus according to a third embodiment of the present invention. [Figure 12]FIG. 12 is a block diagram showing the system configuration of the image forming apparatus according to the fourth embodiment of the present invention. [Figure 13] FIG. 13 is a front view showing the configurations of the image forming unit, sheet conveying unit, and line sensor of the image forming apparatus according to the fourth embodiment of the present invention.

Embodiments of the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of embodying the present invention and do not limit the technical scope of the present invention.

[0011] [Configuration of Image Forming Apparatus 100] First, the configuration of the image forming apparatus 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. In FIG. 3, the sheet conveyance path is indicated by a two-dot chain line with an arrow.

[0012] The image forming apparatus 100 is a printer capable of forming an image on a sheet by an inkjet method. Note that the present invention may be applied to a facsimile apparatus, a copying machine, or a multifunction machine capable of forming an image on a sheet by an inkjet method.

[0013] As shown in FIG. 1, the image forming apparatus 100 includes a paper feeding unit 1, an image forming unit 2, a sheet conveying unit 3, a drying unit 4, an imaging unit 5, an image processing unit 6, an operation display unit 7, and a control unit 8. The image forming apparatus 100 also includes a first housing 100A, a second housing 100B, a third housing 100C, and a paper discharge tray 100D shown in FIG. 2.

[0014] The first housing 100A houses the paper feeding unit 1. The second housing 100B houses the image forming unit 2, the sheet conveying unit 3, the imaging unit 5, the image processing unit 6, and the control unit 8. An operation display unit 7 is provided above the second housing 100B. The third housing 100C houses the drying unit 4. Sheets on which images are formed are discharged onto the paper discharge tray 100D.

[0015] As shown in FIG. 2, the second housing 100B includes an exterior cover 100E. The exterior cover 100E is provided so as to be able to open and close an opening formed in the front of the second housing 100B. For example, the exterior cover 100E is provided so as to be rotatable about a rotation axis 100F along the vertical direction shown in FIG. 2. A user of the image forming apparatus 100 can check the states of the image forming unit 2 and the sheet conveying unit 3 housed in the second housing 100B by opening the exterior cover 100E.

[0016] The paper feeding unit 1 includes a paper feeding cassette (not shown). The paper feeding cassette houses sheets on which images are to be formed. The paper feeding unit 1 supplies the sheets housed in the paper feeding cassette to the second housing 100B.

[0017] The image forming unit 2 forms an image on the sheet supplied to the second housing 100B by the paper feeding unit 1. As shown in FIG. 3, the image forming unit 2 includes line heads 11 to 14 and a head frame 15.

[0018] As shown in FIG. 4, each of the line heads 11 to 14 is long in the width direction D12 (see FIG. 4) orthogonal to the sheet conveying direction D11 (see FIGS. 3 and 4). Specifically, each of the line heads 11 to 14 has a length corresponding to the width of the largest-size sheet that can be housed in the paper feeding cassette in the width direction D12. The line heads 11 to 14 are arranged side by side at equal intervals along the conveying direction D11.

[0019] As shown in Figure 4, each of the line heads 11 to 14 has multiple recording heads 10. Each recording head 10 ejects ink toward the sheet being transported by the conveyor belt 21 of the sheet transport unit 3. Each recording head 10 on line head 11 ejects black ink. Each recording head 10 on line head 12 ejects cyan ink. Each recording head 10 on line head 13 ejects magenta ink. Each recording head 10 on line head 14 ejects yellow ink. Line heads 11 to 14 are examples of the ink ejection units of the present invention.

[0020] Each recording head 10 is equipped with multiple nozzles 10A (see Figure 4) for ejecting ink. The multiple nozzles 10A are provided on the surface of the recording head 10 that faces the sheet being transported by the sheet transport unit 3.

[0021] Each recording head 10 is equipped with a pressure chamber (not shown), a piezoelectric element (not shown), and an individual flow path (not shown) corresponding to each nozzle 10A. The pressure chamber communicates with the nozzle 10A and contains ink. The piezoelectric element causes ink to be ejected from the nozzle 10A by changing the volume of the pressure chamber in response to the application of a predetermined drive voltage. The individual flow path is an ink flow path provided between the pressure chamber and a common flow path (not shown) common to the multiple nozzles 10A. Multiple individual flow paths corresponding to the multiple nozzles 10A are connected to the common flow path. The common flow path is connected to an ink supply unit (not shown) that supplies ink to each of the pressure chambers.

[0022] As shown in Figure 4, line head 11 has three recording heads 10 arranged in a staggered pattern along the width direction D12. Similarly, each of the other line heads 12 to 14 also has three recording heads 10 arranged in a staggered pattern along the width direction D12, just like line head 11.

[0023] The head frame 15 supports the line heads 11 to 14. The head frame 15 is supported by the second housing 100B. Note that the number of line heads provided in the image forming unit 2 does not have to be four. Also, the number of recording heads 10 provided on each of the line heads 11 to 14 does not have to be three.

[0024] The image forming unit 2 forms an image on the sheet based on the print data. The print data is data generated based on the image data to be printed. Specifically, the print data includes ejection data corresponding to each nozzle 10A. The ejection data is data indicating the amount of ink ejected from the nozzle 10A. The print data is generated by converting each pixel included in the image data into the ejection data. The image forming unit 2 controls the ejection of ink by each of the line heads 11 to 14 based on the print data.

[0025] As shown in Figure 3, the sheet transport unit 3 is positioned below the line heads 11-14. The sheet transport unit 3 transports the sheets while keeping them facing the recording head 10. As shown in Figure 3, the sheet transport unit 3 comprises a transport belt 21 on which the sheets are placed, a first tension roller 22, a second tension roller 23, and a third tension roller 24 that tension the transport belt 21, and a transport frame 25 that supports them. The gap between the transport belt 21 and the recording head 10 is adjusted so that the gap between the surface of the sheet and the recording head 10 during image formation is a predetermined distance (for example, 1 mm).

[0026] The first tension roller 22 rotates by receiving rotational driving force supplied from a motor (not shown). As a result, the conveyor belt 21 conveys the sheet along the conveying path shown by the dashed line with arrows in Figure 3. The conveyor belt 21 is driven at a constant speed at a predetermined specific speed.

[0027] As shown in Figure 5, the conveyor belt 21 is equipped with numerous intake holes 21A. Also, as shown in Figure 3, the sheet conveying unit 3 is equipped with an intake device 26 located inside the conveyor belt 21. The intake device 26 draws in air from the numerous intake holes 21A of the conveyor belt 21. As a result, the sheets being conveyed by the conveyor belt 21 are attracted to the surface of the conveyor belt 21.

[0028] As shown in Figure 5, the conveyor belt 21 is provided with a plurality of home position holes 21B. The home position holes 21B are provided at predetermined intervals along the circumferential direction of the conveyor belt 21 at one end of the conveyor belt 21 in the width direction D12. The home position holes 21B are an example of a marker of the present invention.

[0029] In the second housing 100B, the sheet on which the image has been formed by the image forming unit 2 is supplied to the third housing 100C.

[0030] The drying unit 4 dries the ink image formed on the sheet by the image forming unit 2. For example, the drying unit 4 dries the ink image formed on the sheet by heating the sheet.

[0031] In the third enclosure 100C, the sheet on which the ink image has been dried by the drying unit 4 is discharged into the output tray 100D.

[0032] The imaging unit 5 images the transport belt 21.

[0033] As shown in Figure 1, the imaging unit 5 includes a line sensor 31 and an AFE (analog front end) circuit 32.

[0034] As shown in Figure 3, the line sensor 31 is located upstream of the ink ejection position (the position between the line heads 11-14 and the conveyor belt 21) in the sheet conveying path, in the sheet conveying path. The line sensor 31 is also located above the conveyor belt 21. Furthermore, as shown in Figure 4, the line sensor 31 is installed in a long length along the width direction D12. The line sensor 31 images the conveyor belt 21 and the sheets being conveyed by the conveyor belt 21.

[0035] Specifically, the line sensor 31 is a CIS (contact image sensor). The line sensor 31 includes a plurality of image sensors arranged in a line in the width direction D12 (see Figure 4). Each of the image sensors includes a light-emitting unit and a light-receiving unit. The light-emitting unit emits light toward the conveyor belt 21. The light-receiving unit is provided to receive light emitted from the light-emitting unit and reflected by the conveyor belt 21 or the conveyed sheet, and outputs an analog electrical signal according to the amount of light received. The line sensor 31 images the object to be imaged (conveyor belt 21 or sheet) at an imaging cycle corresponding to the specific speed. Specifically, the line sensor 31 outputs an analog electrical signal corresponding to the image of the object to be imaged at the imaging cycle. The outer surface of the conveyor belt 21 is colored gray, for example, a color that suppresses the reflection of light emitted from the light-emitting unit more than the sheet's base color (white), and reflects light emitted from the light-emitting unit more than ink.

[0036] The AFE circuit 32 is an electronic circuit that converts the analog electrical signal output from the line sensor 31 into a digital electrical signal (image data). For example, the AFE circuit 32 converts the analog electrical signal output from the line sensor 31 into monochrome image data composed of 256 pixels with gradations from "0" to "255". For example, a pixel with a gradation value of "0" represents white. Also, a pixel with a gradation value of "255" represents black. The image data output from the AFE circuit 32 (hereinafter referred to as "line data") is stored in a predetermined first area in the RAM 53 of the control unit 8. Note that a pixel with a gradation value of "0" may represent black, and a pixel with a gradation value of "255" may represent white.

[0037] The image processing unit 6 is an electronic circuit that processes the print data using the image data output from the imaging unit 5. The image processing unit 6 is composed of electronic circuits such as integrated circuits (ASIC, DSP, FPGA). As shown in Figure 1, the image processing unit 6 includes a binarization processing unit 41 and a mask processing unit 42.

[0038] The binarization processing unit 41 reads the line data (an example of an image captured in the present invention) stored in the first area of ​​the RAM 53 and binarizes each pixel included in the line data into a sheet pixel (an example of a third pixel in the present invention) indicating a sheet, or a non-sheet pixel (an example of a fourth pixel in the present invention) indicating an object different from a sheet. Specifically, the binarization processing unit 41 binarizes each pixel included in the line data by comparing the tonal value of each pixel included in the line data with a predetermined threshold. More specifically, if the tonal value of a pixel included in the line data is less than the threshold (the tonal value is brighter than the pixel at the threshold), the binarization processing unit 41 converts the pixel into a sheet pixel. Also, if the tonal value of a pixel included in the line data is greater than or equal to the threshold (the tonal value is darker than the pixel at the threshold), the binarization processing unit 41 converts the pixel into a non-sheet pixel. The non-sheet pixels represent the conveyor belt 21, the air intake holes 21A formed in the conveyor belt 21, or ink stains adhering to the surface of the conveyor belt 21. The binarization processing unit 41 stores the line data after binarization in a predetermined second area in the RAM 53 of the control unit 8, which is different from the first area.

[0039] The mask processing unit 42 masks the area outside the sheet in the print data based on the line data that has been binarized by the binarization processing unit 41.

[0040] The image forming unit 2 receives the print data that has been masked by the mask processing unit 42. This makes it possible to suppress the ejection of ink into the area outside the sheet being transported by the transport belt 21.

[0041] The operation display unit 7 is the user interface of the image forming apparatus 100. The operation display unit 7 comprises a display unit and an operation unit. The display unit displays various information in response to control instructions from the control unit 8. For example, the display unit is a flat panel display such as a liquid crystal display. The operation unit inputs various information to the control unit 8 in response to user operations. For example, the operation unit includes operation keys and a touch panel.

[0042] The control unit 8 comprehensively controls the image forming apparatus 100. As shown in Figure 1, the control unit 8 includes a CPU 51, ROM 52, RAM 53, and non-volatile memory 54. The CPU 51 is a processor that performs various arithmetic operations. The ROM 52 is a non-volatile memory device in which information such as control programs for causing the CPU 51 to perform various operations is pre-stored. The RAM 53 is a volatile or non-volatile memory device used as temporary storage memory (work area) for various operations performed by the CPU 51. The non-volatile memory 54 is a non-volatile memory device. The CPU 51 comprehensively controls the image forming apparatus 100 by executing various control programs pre-stored in the ROM 52.

[0043] Incidentally, an image forming apparatus capable of detecting dirt on the conveyor belt 21 using an optical sensor is known as a related technology.

[0044] In this case, if there are any abnormalities on the conveyor belt 21, such as ink stains or scratches, it is desirable to clean or replace the conveyor belt 21. However, in the image forming apparatus relating to the above-mentioned related technology, information regarding such abnormalities is not communicated to the user. Therefore, it is difficult for the user to clean or replace the conveyor belt 21.

[0045] In contrast, the image forming apparatus 100 according to the first embodiment of the present invention can provide information regarding the abnormal location on the conveyor belt 21, as described below.

[0046] [Configuration of Control Unit 8] Next, the configuration of the control unit 8 will be described with reference to Figure 1.

[0047] As shown in Figure 1, the control unit 8 includes a rotation processing unit 61, a first detection processing unit 62, a first count processing unit 63, a second detection processing unit 64, a second count processing unit 65, and a notification processing unit 66.

[0048] Specifically, the ROM 52 of the control unit 8 contains pre-stored operation control programs for enabling the control unit 8 to function as each of the aforementioned processing units. The CPU 51 of the control unit 8 executes these operation control programs, thereby enabling it to function as each of the processing units shown in Figure 1.

[0049] Furthermore, some or all of the processing units included in the control unit 8 may be composed of electronic circuits. Also, the operation control program may be a program that causes multiple processors to function as the processing units shown in Figure 1.

[0050] The rotation processing unit 61 rotates the conveyor belt 21 at least once and then stops it.

[0051] For example, the rotation processing unit 61 stops the conveyor belt 21 after it has started rotating and when its rotational speed has reached the specified speed, at the moment when the conveyor belt 21 has completed one full rotation.

[0052] The first detection processing unit 62 uses the imaging unit 5 to detect the abnormal location on the conveyor belt 21 while the conveyor belt 21 is being rotated by the rotation processing unit 61. The first detection processing unit 62 is an example of the detection processing unit of the present invention.

[0053] Specifically, the first detection processing unit 62 causes the imaging unit 5 to output the line data from the time the rotational speed of the conveyor belt 21 reaches the specified speed until the conveyor belt 21 completes one full rotation. The first detection processing unit 62 also detects the abnormal location based on the line data stored in the first area of ​​the RAM 53.

[0054] For example, the first detection processing unit 62 excludes the pixels representing the air intake holes 21A from a plurality of pixels included in the line data, and identifies the pixel with the highest gradation value (the darkest pixel) among the remaining pixels. The first detection processing unit 62 then determines that there is an abnormality if the gradation value of the identified pixel is equal to or greater than a predetermined first determination value. The first detection processing unit 62 also determines that there is no abnormality if the gradation value of the identified pixel is less than the first determination value. The first determination value is set based on the gradation value of each pixel representing each color of ink when the four colors of ink attached to the transport belt 21 are imaged using the imaging unit 5. Alternatively, the first determination value may be set based on the gradation value of the pixel representing a scratch when the scratch attached to the transport belt 21 is imaged using the imaging unit 5. Furthermore, the first determination value may be arbitrarily changed according to user operation on the operation display unit 7.

[0055] The first counting unit 63 uses the imaging unit 5 to count the number of home position holes 21B (see Figure 5) that pass through the imaging position of the imaging unit 5 between the time of detection of the abnormal location by the first detection unit 62 and a predetermined reference time. Specifically, the first counting unit 63 counts the number of home position holes 21B that pass through the imaging position of the imaging unit 5 from the time of detection of the abnormal location by the first detection unit 62 until the time of stopping of the conveyor belt 21 by the rotation unit 61 (an example of the reference time). The first counting unit 63 is an example of a counting unit of the present invention.

[0056] Specifically, the first count processing unit 63 detects that the home position hole 21B has passed the imaging position based on the line data stored in the first area of ​​the RAM 53.

[0057] The image forming apparatus 100 may also be equipped with a dedicated sensor for detecting the home position holes 21B, separate from the line sensor 31. In this case, the first counting unit 63 can use the dedicated sensor to count the number of home position holes 21B that pass through the imaging position.

[0058] The second detection processing unit 64 uses the imaging unit 5 to detect sheets that adhere to the conveyor belt 21 while the conveyor belt 21 is being rotated by the rotation processing unit 61.

[0059] Specifically, the second detection processing unit 64 detects sheets adhering to the conveyor belt 21 based on the line data stored in the first area of ​​the RAM 53.

[0060] For example, the second detection processing unit 64 identifies the pixel with the lowest gradation value (the brightest pixel) among the pixels included in the line data. The second detection processing unit 64 then determines that a sheet is present if the gradation value of the identified pixel is less than a predetermined second determination value. The second detection processing unit 64 also determines that there is no sheet if the gradation value of the identified pixel is equal to or greater than the second determination value. The second determination value is set based on the gradation value of the pixel representing the sheet when the sheet attached to the transport belt 21 is imaged using the imaging unit 5. The second determination value may be arbitrarily changed according to user operation on the operation display unit 7.

[0061] The second counting unit 65, similar to the first counting unit 63, uses the imaging unit 5 to count the number of home position holes 21B (see Figure 5) that pass through the imaging position from the time the second detection unit 64 detects the sheet until the conveyor belt 21 stops.

[0062] Specifically, the second count processing unit 65 detects that the home position hole 21B has passed the imaging position based on the line data stored in the first area of ​​the RAM 53.

[0063] When the abnormal location is detected by the first detection processing unit 62, the notification processing unit 66 notifies the detection of the abnormal location and the count result from the first count processing unit 63 after the conveyor belt 21 has stopped.

[0064] For example, the notification processing unit 66 causes the operation display unit 7 to display a first notification screen that includes a message indicating that the abnormal location has been detected and first location information indicating the location of the abnormal location. The first location information includes the count result from the first count processing unit 63. The first location information also includes information indicating the location of the abnormal location in the width direction D12, which is identified based on the line data.

[0065] Furthermore, when the second detection processing unit 64 detects a sheet adhering to the conveyor belt 21, the notification processing unit 66 notifies the detection of the sheet adhering to the conveyor belt 21 and the count result from the second count processing unit 65 after the conveyor belt 21 has stopped.

[0066] For example, the notification processing unit 66 causes the operation display unit 7 to display a second notification screen that includes a message indicating that a sheet attached to the conveyor belt 21 has been detected, and second position information indicating the position of the sheet. The second position information includes the count result from the second count processing unit 65. The second position information also includes information indicating the position of the sheet in the width direction D12, which is determined based on the line data.

[0067] [First Anomaly Notification Processing] The notification method of the present invention will be described below with reference to Figure 6, along with an example of the procedure for the first abnormality notification process executed by the control unit 8 in the image forming apparatus 100. Here, steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 8.

[0068] For example, the first abnormality notification process is executed when a predetermined execution timing arrives. For example, the execution timing includes the time when the image forming apparatus 100 is powered on. The execution timing also includes the time when the operating mode of the image forming apparatus 100 transitions from a power-saving mode, which consumes less power than the normal mode, to the normal mode. The execution timing also includes the time when an execution instruction for the printing process of forming an image on a sheet is input.

[0069] <Step S11> First, in step S11, the control unit 8 starts driving the conveyor belt 21.

[0070] When the rotational speed of the conveyor belt 21 reaches the specified speed, the control unit 8 inputs an instruction to the imaging unit 5 to output the line data. As a result, the imaging unit 5 outputs the line data at the imaging cycle, and the line data is stored in the first area of ​​the RAM 53.

[0071] <Step S12> In step S12, the control unit 8 determines whether or not the line data has been output from the imaging unit 5.

[0072] Here, if the control unit 8 determines that the line data has been output from the imaging unit 5 (Yes side of S12), it proceeds to step S13. If the line data has not been output from the imaging unit 5 (No side of S12), the control unit 8 waits for the line data to be output from the imaging unit 5 in step S12.

[0073] <Step S13> In step S13, the control unit 8 executes the abnormality detection process described below.

[0074] [Anomaly detection processing] Now, with reference to Figure 7, the anomaly detection process performed in step S13 of the first anomaly notification process will be described.

[0075] <Step S21> First, in step S21, the control unit 8 detects the abnormal location based on the line data that was last stored in the first area of ​​the RAM 53. The processing in step S21 is an example of the detection steps of the present invention and is performed by the first detection processing unit 62 of the control unit 8.

[0076] <Step S22> In step S22, the control unit 8 determines whether or not the abnormal location was detected by the processing in step S21.

[0077] If the control unit 8 determines that the abnormal location has been detected (Yes in S22), it proceeds to step S23. If the abnormal location has not been detected (No in S22), the control unit 8 proceeds to step S25.

[0078] <Step S23> In step S23, the control unit 8 records the detection of the abnormal location.

[0079] Specifically, the control unit 8 generates first detection information, which includes information indicating the date and time of detection of the abnormal location and information indicating the location of the abnormal location in the width direction D12. The control unit 8 also stores the generated first detection information in its non-volatile memory 54.

[0080] <Step S24> In step S24, the control unit 8 starts counting the number of home position holes 21B (see Figure 5) that pass through the imaging position. The processing in step S24 is an example of the counting step of the present invention and is performed by the first count processing unit 63 of the control unit 8.

[0081] The count initiated by the process in step S24 continues until the process in step S15 (see Figure 6) of the first abnormality notification process is executed. The count result of the number of home position holes 21B passing through the imaging position is stored in the non-volatile memory 54 of the control unit 8 as part of the first detection information.

[0082] <Step S25> In step S25, the control unit 8 detects the sheet attached to the conveyor belt 21 based on the line data that was last stored in the first area of ​​the RAM 53. The processing in step S25 is performed by the second detection processing unit 64 of the control unit 8.

[0083] <Step S26> In step S26, the control unit 8 determines whether or not a sheet attached to the conveyor belt 21 has been detected by the processing in step S25.

[0084] If the control unit 8 determines that a sheet has been detected (Yes in S26), it proceeds to step S27. If no sheet has been detected (No in S26), the control unit 8 terminates the abnormality detection process.

[0085] <Step S27> In step S27, the control unit 8 records the detection of a sheet attached to the conveyor belt 21.

[0086] Specifically, the control unit 8 generates second detection information, which includes information indicating the date and time of sheet detection and information indicating the position of the sheet in the width direction D12. The control unit 8 also stores the generated second detection information in its non-volatile memory 54.

[0087] <Step S28> In step S28, the control unit 8 starts counting the number of home position holes 21B (see Figure 5) that pass through the imaging position. The processing in step S28 is performed by the second count processing unit 65 of the control unit 8.

[0088] The count initiated by the process in step S28 continues until the process in step S15 (see Figure 6) of the first abnormality notification process is executed. The count result of the number of home position holes 21B passing through the imaging position is stored in the non-volatile memory 54 of the control unit 8 as part of the second detection information.

[0089] This concludes the explanation of the anomaly detection process, and we will now resume the explanation of the first anomaly notification process.

[0090] <Step S14> In step S14, the control unit 8 determines whether the conveyor belt 21 has completed one full rotation from the moment the rotational speed of the conveyor belt 21 reaches the specified speed.

[0091] Here, if the control unit 8 determines that the conveyor belt 21 has completed one full rotation (Yes side of S14), it proceeds to step S15. If the conveyor belt 21 has not completed one full rotation (No side of S14), the control unit 8 proceeds to step S12. As a result, steps S12 and S13 are executed until the conveyor belt 21 has completed one full rotation.

[0092] <Step S15> In step S15, the control unit 8 stops driving the conveyor belt 21. The processes in steps S11, S14, and S15 are examples of the rotation steps of the present invention and are performed by the rotation processing unit 61 of the control unit 8.

[0093] <Step S16> In step S16, the control unit 8 determines whether or not either the abnormal location and / or the sheet attached to the conveyor belt 21 have been detected.

[0094] If the control unit 8 determines that either or both of the abnormal location and the sheet attached to the conveyor belt 21 have been detected (Yes in S16), it proceeds to step S17. If either or both of the abnormal location and the sheet attached to the conveyor belt 21 have not been detected (No in S16), the control unit 8 terminates the first abnormality notification process.

[0095] <Step S17> In step S17, the control unit 8 performs a notification process to notify the detection of either or both of the abnormal location and the sheet attached to the conveyor belt 21. The process in step S17 is an example of the notification step of the present invention and is performed by the notification processing unit 66 of the control unit 8.

[0096] Specifically, if only the abnormal area is detected, the control unit 8 displays the first notification screen on the operation display unit 7. If only the sheet is detected, the control unit 8 displays the second notification screen on the operation display unit 7. If both the abnormal area and the sheet are detected, the control unit 8 displays both the first notification screen and the second notification screen on the operation display unit 7.

[0097] Here, the first notification screen includes the counting result from the first counting processing unit 63. This allows the user to open the outer cover 100E (see Figure 2) and manually reverse the transport belt 21 so that the home position holes 21B pass through the imaging position a number of times equal to the counting result from the first counting processing unit 63, thereby moving the abnormal location to the vicinity of the imaging position. As a result, the user can easily identify the abnormal location.

[0098] In this way, the image forming apparatus 100 can notify information regarding the abnormal location on the conveyor belt 21. Therefore, if the abnormal location is present on the conveyor belt 21, the user can check the abnormal location and determine whether cleaning or replacement of the conveyor belt 21 is necessary.

[0099] [Second Embodiment] The image forming apparatus 100 may also include a switching processing unit 71 and an output processing unit 72 as shown in Figure 8.

[0100] The switching processing unit 71 switches the threshold used for binarizing the line data between a first threshold used for identifying belt pixels (an example of the first pixel of the present invention) corresponding to the transport belt and abnormal location pixels (an example of the second pixel of the present invention) corresponding to the abnormal location, and a second threshold used for identifying sheet pixels and non-sheet pixels.

[0101] The binarization processing unit 41, when the threshold is set to the first threshold, binarizes each pixel included in the line data into either the belt pixel or the abnormal location pixel. Specifically, if the tonal value of a pixel included in the line data is less than the threshold (the first threshold), the binarization processing unit 41 converts the pixel into the belt pixel. Also, if the tonal value of a pixel included in the line data is equal to or greater than the threshold (the first threshold), the binarization processing unit 41 converts the pixel into the abnormal location pixel. The belt pixel represents the conveyor belt 21 or a sheet attached to the conveyor belt 21. The abnormal location pixel represents an air intake hole 21A formed in the conveyor belt 21, or ink stains attached to the surface of the conveyor belt 21.

[0102] Furthermore, when the threshold is set to the second threshold, the binarization processing unit 41 binarizes each pixel included in the line data into either the sheet pixel or the non-sheet pixel.

[0103] Furthermore, the mask processing unit 42 masks the area outside the sheet in the print data to be printed on the sheet, based on the line data that has been binarized by the binarization processing unit 41 using the second threshold.

[0104] In other words, by providing the switching processing unit 71, the binarization processing unit 41 can be used for both generating the data used for the mask of the print data and generating the belt image described later.

[0105] The output processing unit 72 outputs the line data acquired by the imaging unit 5 when the abnormal location is detected by the first detection processing unit 62.

[0106] For example, the output processing unit 72 outputs the line data after it has been binarized using the first threshold by the binarization processing unit 41. In other words, the output processing unit 72 outputs the line data that has been stored in the second area of ​​the RAM 53 of the control unit 8 by the binarization processing unit 41.

[0107] For example, the output processing unit 72 causes the operation display unit 7 to display a belt image on the operation display unit 7, which is composed of the line data after binarization using the first threshold by the binarization processing unit 41. The belt image is composed of a plurality of line data acquired while the conveyor belt 21 rotates once.

[0108] The output processing unit 72 may also print the belt image onto a sheet using the image forming unit 2. The output processing unit 72 may also transmit the belt image to a pre-specified destination.

[0109] [Second Anomaly Notification Processing] Hereinafter, with reference to Figure 9, an example of the procedure for the second abnormality notification process executed by the control unit 8 in the image forming apparatus 100 according to another embodiment will be described.

[0110] As shown in Figures 6 and 9, the content of the second abnormality notification process is the same as that of the first abnormality notification process, except that the processes in steps S31 to S35 are added. Therefore, only the processes in steps S31 to S35 will be explained below.

[0111] <Step S31> In step S31, the control unit 8 determines whether or not the abnormal location has been detected.

[0112] If the control unit 8 determines that the abnormal location has been detected (Yes side of S31), it proceeds to step S32. If the abnormal location has not been detected (No side of S31), the control unit 8 proceeds to step S17.

[0113] <Step S32> In step S32, the control unit 8 switches the threshold from the second threshold to the first threshold. The process in step S32 is performed by the switching processing unit 71 of the control unit 8.

[0114] <Step S33> In step S33, the control unit 8 executes a data acquisition process to acquire the belt image.

[0115] Specifically, the control unit 8 drives the conveyor belt 21 again. More specifically, the control unit 8 drives the conveyor belt 21 from the time the rotational speed of the conveyor belt 21 reaches the specified speed until the conveyor belt 21 completes one full rotation.

[0116] Furthermore, the control unit 8 causes the imaging unit 5 to output the line data while the conveyor belt 21 is being driven.

[0117] Furthermore, the control unit 8 instructs the binarization processing unit 41 to binarize the line data output by the imaging unit 5. As a result, each pixel included in the line data is binarized into either the belt pixel or the abnormal location pixel. The binarized line data (a part of the belt image) is then stored in the second area of ​​the RAM 53.

[0118] <Step S34> In step S34, the control unit 8 switches the threshold from the first threshold to the second threshold. The process in step S34 is performed by the switching processing unit 71 of the control unit 8.

[0119] <Step S35> In step S35, the control unit 8 outputs the belt image acquired by the data acquisition process. The processing in step S35 is performed by the output processing unit 72 of the control unit 8.

[0120] Specifically, the control unit 8 displays the belt image on the operation display unit 7. This allows the user to check the shape of the abnormal area without opening the outer cover 100E.

[0121] [Third Embodiment] Furthermore, the image forming apparatus 100 may also include a movement processing unit 81 shown in Figure 10 and a window section 27 shown in Figure 11.

[0122] The window portion 27 is provided on the outer surface of the second housing 100B (see Figure 11) (an example of a housing of the present invention) so that a part of the outer surface of the conveyor belt 21 can be seen from outside the second housing 100B (see Figure 11) (an example of a housing of the present invention).

[0123] For example, as shown in Figure 11, the window portion 27 is provided in the outer cover 100E. The window portion 27 is an opening formed in the outer cover 100E and is closed by a light-transmitting material such as glass. For example, the window portion 27 is provided in the outer cover 100E such that the portion of the outer surface of the conveyor belt 21 located below the line sensor 31 (see Figure 3) is visible from outside the second housing 100B.

[0124] Based on the count result from the first count processing unit 63, which is notified by the notification processing unit 66, the movement processing unit 81 moves the abnormal location to a visible area that can be seen from outside the second housing 100B through the window 27.

[0125] For example, the movement processing unit 81 reverses the rotation of the transport belt 21 so that the home position holes 21B pass through the imaging position a number of times equal to the number of count results from the first count processing unit 63.

[0126] Here, when the first detection processing unit 62 detects the abnormal location, the notification processing unit 66 notifies the user of the detection of the abnormal location after the conveyor belt 21 has stopped, and notifies the movement processing unit 81 of the count result from the first count processing unit 63. For example, after the movement processing unit 81 has moved the abnormal location, the notification processing unit 66 displays on the operation display unit 7 a message indicating that the abnormal location has been detected and a message indicating that the abnormal location is visible from the window 27.

[0127] This allows the user to check for abnormalities without having to open the outer cover 100E (see Figure 11) and manually reverse the transport belt 21 so that the home position holes 21B pass through the imaging position a number of times equal to the count result from the first count processing unit 63.

[0128] Furthermore, the movement processing unit 81 may move the sheet attached to the conveyor belt 21 to a visible range that can be seen from outside the second housing 100B through the window 27, based on the count result from the second count processing unit 65 which is notified by the notification processing unit 66.

[0129] Furthermore, when the second detection processing unit 64 detects a sheet adhering to the conveyor belt 21, the notification processing unit 66 may, after the conveyor belt 21 stops, notify the user of the detection of a sheet adhering to the conveyor belt 21 and notify the second count processing unit 65 of the count result to the movement processing unit 81. For example, after the movement processing unit 81 moves the sheet adhering to the conveyor belt 21, the notification processing unit 66 may display on the operation display unit 7 a message indicating that a sheet adhering to the conveyor belt 21 has been detected, and a message indicating that the sheet adhering to the conveyor belt 21 is visible from the window 27.

[0130] [Modified version of the third embodiment] One of the multiple home position holes 21B (see Figure 5) may have a different visual appearance from the other home position holes 21B. For example, one of the multiple home position holes 21B may be larger in size than the other home position holes 21B. Also, one of the multiple home position holes 21B may have a different shape from the other home position holes 21B. Hereinafter, a home position hole 21B that has a different visual appearance from the other home position holes 21B will be referred to as a "reference hole" (an example of a reference marker in the present invention). Note that the marker in the present invention is not limited to holes, but may also be a colored area. In this case, the reference marker in the present invention may be a marker with a different color from the other markers.

[0131] In this case, the rotation processing unit 61 may stop the conveyor belt 21 after the rotational speed of the conveyor belt 21 has reached the specified speed and the reference hole has passed the imaging position, at the timing when the conveyor belt 21 has completed one full rotation.

[0132] Furthermore, the first counting unit 63 may count the number of home position holes 21B that pass through the imaging position from the time the reference hole passes through the imaging position (another example of the reference time) while the conveyor belt 21 is being rotated by the rotation processing unit 61 until the first detection processing unit 62 detects the abnormal location.

[0133] Furthermore, the movement processing unit 81 may move the abnormal location to a visible area visible from outside the second housing 100B through the window 27, based on the count result from the first count processing unit 63 which is notified by the notification processing unit 66. For example, the movement processing unit 81 may rotate the transport belt 21 until the number of times the home position hole 21B passes the imaging position since the reference hole passed the imaging position matches the count result from the first count processing unit 63 which is notified by the notification processing unit 66.

[0134] Furthermore, the second counting unit 65 may count the number of home position holes 21B that pass through the imaging position from the time the reference hole passes through the imaging position until the sheet is detected by the second detection unit 64, while the conveyor belt 21 is being rotated by the rotation unit 61.

[0135] Furthermore, the movement processing unit 81 may move the sheet attached to the conveyor belt 21 to a visible range that can be seen from outside the second housing 100B through the window 27, based on the count result from the second count processing unit 65 which is notified by the notification processing unit 66.

[0136] [Fourth Embodiment] Furthermore, the image forming apparatus 100 may also include a cleaning processing unit 82 shown in Figure 12 and a cleaning unit 28 shown in Figure 13.

[0137] The cleaning unit 28 is provided to be movable between a cleaning position in which it contacts and cleans the conveyor belt 21, and a retracted position where it is moved away from the cleaning position. For example, the cleaning unit 28 comprises a cleaning member and a support member. For example, the cleaning member is a rubber blade. The cleaning position is the position where the cleaning member contacts the conveyor belt 21 (see Figure 13). The retracted position is the position where the cleaning member is separated from the conveyor belt 21. The support member movably supports the cleaning member. The support member is supported by the conveyor frame 25 so as to be movable between the cleaning position and the retracted position along the direction of the arrow shown in Figure 13. The cleaning unit 28 is positioned in the retracted position except when the conveyor belt 21 is being cleaned.

[0138] When the first detection processing unit 62 detects the abnormal area, the cleaning processing unit 82 performs a cleaning process to clean the conveyor belt 21 using the cleaning unit 28.

[0139] For example, in the cleaning process, with the cleaning unit 28 positioned at the cleaning location, the conveyor belt 21 is rotated at least once.

[0140] Here, if the first detection processing unit 62 does not detect the abnormal location, the rotation processing unit 61 stops the conveyor belt 21 when the conveyor belt 21 has completed one full rotation after reaching the specified speed. Also, if the first detection processing unit 62 detects the abnormal location, the rotation processing unit 61 stops the conveyor belt 21 when the conveyor belt 21 has completed three or more full rotations after reaching the specified speed.

[0141] Furthermore, the cleaning processing unit 82 executes the cleaning process from the moment the rotational speed of the conveyor belt 21 reaches the specified speed until after the conveyor belt 21 has completed one rotation.

[0142] Furthermore, the first detection processing unit 62 detects the abnormal location again after the cleaning process has been performed.

[0143] Furthermore, the first counting unit 63 counts the number of home position holes 21B that pass through the imaging position between the time of detection of the abnormal area by the first detection unit 62 after the cleaning process and the reference time. For example, the first counting unit 63 counts the number of home position holes 21B that pass through the imaging position from the time of detection of the abnormal area by the first detection unit 62 after the cleaning process until the conveyor belt 21 is stopped by the rotation unit 61. Alternatively, the first counting unit 63 may count the number of home position holes 21B that pass through the imaging position from the time the reference hole passes through the imaging position after the cleaning process until the first detection unit 62 detects the abnormal area.

[0144] Furthermore, if the first detection processing unit 62 detects the abnormal location after the cleaning process has been executed, the notification processing unit 66 will notify the detection of the abnormal location and the count result from the first count processing unit 63 after the conveyor belt 21 has stopped.

[0145] This makes it possible to limit notification to the user of the detection of an abnormal area when the abnormal area detected by the first detection processing unit 62 can be removed by cleaning.

[0146] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0147] <Note 1> An image forming apparatus comprising: a conveyor belt for conveying a sheet; an ink discharge unit for dispensing ink toward the sheet being conveyed by the conveyor belt; a plurality of markers provided on the conveyor belt at predetermined intervals along the circumferential direction of the conveyor belt; an imaging unit for imaging the conveyor belt; a rotation processing unit for rotating the conveyor belt at least once and stopping it; a detection processing unit that uses the imaging unit to detect an abnormal location on the conveyor belt while the conveyor belt is being rotated by the rotation processing unit; a count processing unit that counts the number of markers that pass through the imaging position by the imaging unit between the time of detection of the abnormal location by the detection processing unit and a predetermined reference time; and a notification processing unit that, when the abnormal location is detected by the detection processing unit, notifies the detection of the abnormal location and the count result by the count processing unit after the conveyor belt has stopped.

[0148] <Note 2> The aforementioned reference time includes the time when the conveyor belt is stopped by the rotation processing unit, as described in Appendix 1, for the image forming apparatus.

[0149] <Note 3> The image forming apparatus according to Appendix 1, wherein the plurality of markers include one reference marker that is different from the other markers, and the reference time includes the time when the reference marker passes the imaging position.

[0150] <Note 4> The image forming apparatus according to any one of the appendices 1 to 3, wherein the imaging unit images the conveyor belt upstream of the discharge position in the conveyor path of the sheet, which passes through the ink discharge position by the ink discharge unit, in the direction of conveying the sheet.

[0151] <Note 5> The image forming apparatus according to Appendix 4, further comprising an output processing unit that outputs an image captured by the imaging unit when the detection processing unit detects the abnormal location.

[0152] <Note 6> The image forming apparatus according to Appendix 5, comprising a binarization processing unit that binarizes each pixel in the captured image into a first pixel corresponding to the transport belt or a second pixel corresponding to the abnormal location, and the output processing unit outputs the captured image after binarization by the binarization processing unit.

[0153] <Note 7> The image forming apparatus according to Appendix 6, comprising: a switching processing unit that switches a threshold used for binarizing the captured image between a first threshold used for identifying the first and second pixels and a second threshold used for identifying a third pixel indicating the sheet and a fourth pixel indicating an object different from the sheet; and a masking processing unit that masks the area outside the sheet in the print data to be printed on the sheet based on the captured image binarized by the binarization processing unit using the second threshold.

[0154] <Note 8> An image forming apparatus according to any one of the appendices 1 to 7, comprising: a housing for housing the conveyor belt; a window provided on the outer surface of the housing so that a part of the outer surface of the conveyor belt can be viewed from outside the housing; and a movement processing unit that moves the abnormal location within a visible range that can be viewed from outside the housing through the window, based on the count result notified by the notification processing unit.

[0155] <Note 9> An image forming apparatus according to any one of the appendices 1 to 8, comprising: a cleaning unit provided so as to be movable between a cleaning position in which it contacts the conveyor belt to clean the conveyor belt and a retracted position in which it is retracted from the cleaning position; and a cleaning processing unit which, when an abnormal location is detected by the detection processing unit, performs a cleaning process to clean the conveyor belt using the cleaning unit, wherein the detection processing unit detects the abnormal location again after the cleaning process is performed, the count processing unit counts the number of markers that pass through the imaging position between the time of detection of the abnormal location by the detection processing unit after the cleaning process is performed and the reference time, and the notification processing unit, when an abnormal location is detected by the detection processing unit after the cleaning process is performed, notifies the detection of the abnormal location and the count result by the count processing unit after the conveyor belt has stopped.

[0156] <Note 10> A notification method performed in an image forming apparatus comprising: a conveyor belt for conveying a sheet; an ink discharge unit for discharging ink toward the sheet being conveyed by the conveyor belt; a plurality of markers provided on the conveyor belt at predetermined intervals along the circumferential direction of the conveyor belt; and an imaging unit for imaging the conveyor belt, the notification method comprising: a rotation step for rotating the conveyor belt at least once and stopping it; a detection step for using the imaging unit to detect an abnormal location on the conveyor belt while the conveyor belt is rotating by the rotation step; a count step for counting the number of markers that pass through the imaging position by the imaging unit between the time of detection of the abnormal location by the detection step and a predetermined reference time; and a notification step for notifying the detection of the abnormal location and the count result from the count step after the conveyor belt has stopped, if the abnormal location is detected by the detection step. [Explanation of Symbols]

[0157] 1 Paper feed section 2 Image forming unit 3. Sheet transport section 4 Drying section 5. Imaging Department 6. Image Processing Unit 7 Operation display section 8 Control Unit 10 Recording head 10A Nozzle 11 Line Head 12 line heads 13 Line Head 14 Line Head 15 Headframe 21 Conveyor belt 21A Intake port 21B Home Position Hole 27 Window section 28 Cleaning Department 31 Line Sensor 32 AFE Circuit 41. Binarization Processing Unit 42 Mask Processing Unit 51 CPU 52 ROM 53 RAM 54 Non-volatile memory 61 Rotation Processing Unit 62 First detection processing unit 63. First Count Processing Unit 64 Second Detection Processing Unit 65 Second Count Processing Unit 66 Notification Processing Unit 71 Switching Processing Unit 72 Output Processing Unit 81 Movement Processing Unit 82 Cleaning Processing Unit 100 Image forming apparatus

Claims

1. A conveyor belt for transporting the sheets, An ink dispensing unit that dispenses ink toward the sheet being transported by the conveyor belt, The conveyor belt has a plurality of markers provided at predetermined intervals along the circumferential direction of the conveyor belt, An imaging unit for imaging the aforementioned conveyor belt, A rotation processing unit that rotates the conveyor belt at least once and stops it, A detection processing unit that uses the imaging unit to detect abnormal locations in the conveyor belt while the conveyor belt is being rotated by the rotation processing unit, A counting processing unit that counts the number of markers that pass through the imaging position by the imaging unit between the time of detection of the abnormal location by the detection processing unit and a predetermined reference time, When the detection processing unit detects the abnormal location, a notification processing unit notifies the detection of the abnormal location and the counting result by the counting processing unit after the conveyor belt has stopped. An image forming apparatus equipped with the following features.

2. The aforementioned reference time includes the time when the conveyor belt is stopped by the rotation processing unit. The image forming apparatus according to claim 1.

3. Each of the aforementioned markers includes a reference marker that is different from the other aforementioned markers. The aforementioned reference time includes the time when the reference marker passes the imaging position. The image forming apparatus according to claim 1.

4. The imaging unit images the conveyor belt upstream of the discharge position in the conveyor path of the sheet, which passes through the ink discharge position by the ink discharge unit, in the conveyor path of the sheet. An image forming apparatus according to any one of claims 1 to 3.

5. The system includes an output processing unit that outputs the captured image acquired by the imaging unit when the abnormal location is detected by the detection processing unit. The image forming apparatus according to claim 4.

6. The system includes a binarization processing unit that binarizes each pixel in the captured image into a first pixel corresponding to the conveyor belt or a second pixel corresponding to the abnormal location. The output processing unit outputs the captured image after it has been binarized by the binarization processing unit. The image forming apparatus according to claim 5.

7. A switching processing unit that switches the threshold used for binarizing the captured image between a first threshold used for identifying the first and second pixels and a second threshold used for identifying the third pixel representing the sheet and the fourth pixel representing an object different from the sheet, A masking processing unit that, based on the captured image binarized using the second threshold by the binarization processing unit, masks the area outside the sheet in the print data to be printed on the sheet, The image forming apparatus according to claim 6, comprising:

8. A housing for the aforementioned conveyor belt, A window is provided on the outer surface of the housing so that a part of the outer surface of the conveyor belt can be viewed from outside the housing, A movement processing unit moves the abnormal location to a visible area that can be seen from outside the housing through the window, based on the count result reported by the notification processing unit, An image forming apparatus according to any one of claims 1 to 3, comprising:

9. A cleaning unit is provided that is movable between a cleaning position in which it contacts the conveyor belt to clean the conveyor belt and a retracted position which is moved away from the cleaning position, When the detection processing unit detects the abnormal location, a cleaning processing unit is provided that performs a cleaning process to clean the conveyor belt using the cleaning unit. Equipped with, The detection processing unit detects the abnormal location again after the cleaning process has been executed. The counting processing unit counts the number of markers that pass through the imaging position between the time the detection processing unit detects the abnormal area after the cleaning process is performed and the reference time. The notification processing unit, when the abnormal location is detected by the detection processing unit after the cleaning process is performed, notifies the detection of the abnormal location and the counting result by the counting processing unit after the conveyor belt has stopped. An image forming apparatus according to any one of claims 1 to 3.

10. A notification method performed by an image forming apparatus comprising: a conveyor belt for conveying a sheet; an ink discharge unit for dispensing ink toward the sheet being conveyed by the conveyor belt; a plurality of markers provided on the conveyor belt at predetermined intervals along the circumferential direction of the conveyor belt; and an imaging unit for imaging the conveyor belt, wherein A rotation step in which the conveyor belt is rotated at least once and then stopped, A detection step in which the imaging unit is used to detect an abnormal location in the conveyor belt during the rotation of the conveyor belt by the rotation step, A counting step which counts the number of marks that pass through the imaging position by the imaging unit between the time of detection of the abnormal location by the detection step and a predetermined reference time, If the abnormal location is detected by the detection step, a notification step is performed to notify the detection of the abnormal location and the count result from the count step after the conveyor belt has stopped. A notification method that includes this.

Images