Processing execution device, image forming apparatus, defect detection method, and defect detection program

Abstract

To identify potentially faulty sensors while reducing manufacturing costs. [Solution] The processing execution device comprises a plurality of sensors, a batch detection unit 53 that detects a first number indicating the number of faulty sensors among the plurality of sensors, a normal determination unit 55 that detects whether each of the plurality of sensors is operating normally based on the output value of the sensor, and a fault determination unit 57 that determines one or more faulty sensors among the plurality of sensors based on a second number which is the total number of sensors that are not detected as operating normally by the normal determination unit and the first number.

Description

Technical Field

[0001] The present invention relates to a processing execution device, an image forming device, a defect determination method, and a defect determination program. In particular, the present invention relates to a processing execution device that executes processing using a sensor, an image forming device including the processing execution device, a defect determination method executed by the processing execution device, and a defect determination program that causes a computer to execute the defect determination method.

Background Art

[0002] Image forming devices such as copiers, printers, and facsimile machines execute a process of conveying a recording medium such as paper on which an image is formed, and form an image on the recording medium while the recording medium is being conveyed. While the process of conveying the recording medium is being executed, a plurality of sensors for detecting the presence or absence of the recording medium during conveyance are provided because an error such as the recording medium becoming jammed may occur. On the other hand, in a state where the sensor malfunctions and cannot operate normally, the presence or absence of the recording medium cannot be detected, so an error is detected even though the recording medium is not jammed. Therefore, it is required to detect the state of the sensor.

[0003] Japanese Patent Laid-Open No. 5-26937 discloses an image recording apparatus including control signal output means for supplying a control signal to a plurality of controlled objects, current amount detection means for detecting the amount of current flowing through the controlled object in response to a change in the output of the control signal, determination means for determining whether the control signal output means is normal or abnormal based on the detected amount of current, and power supply control means for cutting off the power supply to the apparatus according to the determination result of the determination means.

[0004] However, while faults can be detected in sensors whose output changes by switching on and off with a control signal, such as through-beam sensors, faults cannot be detected in sensors whose output does not change even when the control signal is switched, such as reflective sensors. Furthermore, faults can also be detected by detecting the value of the current flowing through the sensor, but this requires detecting the current for each sensor, which increases manufacturing costs. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-26937 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] One of the objectives of this invention is to provide a processing device that can identify potentially faulty sensors while reducing manufacturing costs.

[0007] Another objective of this invention is to provide an image forming apparatus capable of identifying potentially faulty sensors while reducing manufacturing costs.

[0008] Another object of this invention is to provide a fault detection method that can identify potentially faulty sensors while reducing manufacturing costs.

[0009] Another object of this invention is to provide a malfunction detection program that can identify potentially faulty sensors while reducing manufacturing costs. [Means for solving the problem]

[0010] According to one aspect of this invention, the processing execution device comprises a plurality of sensors, a batch detection unit that detects a first number indicating the number of faulty sensors among the plurality of sensors, a normal determination unit that detects whether each of the plurality of sensors is operating normally based on the output value of the sensor, and a fault determination unit that determines one or more faulty sensors among the plurality of sensors based on a second number which is the total number of sensors that are not detected as operating normally by the normal determination unit and the first number.

[0011] According to another aspect of this invention, the image forming apparatus comprises the processing execution apparatus described above.

[0012] According to yet another aspect of this invention, a malfunction determination method is a malfunction determination method performed by a processing execution device equipped with a plurality of sensors, and includes: a batch detection step of detecting a first number indicating the number of malfunctioning sensors among the plurality of sensors; a normal determination step of detecting whether each of the plurality of sensors is operating normally based on the output value of the sensor; and a malfunction determination step of determining one or more malfunctioning sensors among the plurality of sensors based on a second number which is the total number of sensors that are not detected to be operating normally in the normal determination step and the first number.

[0013] According to yet another aspect of this invention, the defect detection program causes a computer to execute the above-described defect detection method. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing the external appearance of a printer according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view showing an example of the internal configuration of a printer. [Figure 3] This is a circuit diagram showing an example of the electrical connection relationships of various sensors. [Figure 4] This is a block diagram illustrating the hardware configuration of the printer in this embodiment. [Figure 5]It is a block diagram showing an example of the functions of the CPU included in the printer. [Figure 6] It is a diagram showing an example of the current consumption value of the sensor. [Figure 7] It is a diagram showing an example of a reference value with respect to the total current consumption of four sensors. [Figure 8] It is a diagram showing an example of a threshold value. [Figure 9] It is a diagram showing an example of a defect determination process. [Figure 10] It is a diagram showing an example of the states of a plurality of sensors. [Figure 11] It is a diagram showing an example of the states of a plurality of sensors at a first point in time. [Figure 12] It is a diagram showing an example of the states of a plurality of sensors at a second point in time.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0016] FIG. 1 is a perspective view showing the appearance of a printer in one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of the internal configuration of the printer. Hereinafter, for the sake of explanation, the left-right direction in FIG. 2 is referred to as the left-right direction, and the front-back direction is referred to as the depth direction. The direction from left to right in the left-right direction is referred to as the right-side direction, and the direction from right to left is referred to as the left-side direction. The direction from the front to the back in the depth direction is referred to as the front direction, and the direction from the back to the front is referred to as the back direction.

[0017] Referring to FIGS. 1 and 2, printer 100 is an example of an image forming apparatus, and includes an image forming unit 140 for forming an image on a recording medium based on image data, a paper feeding unit 150 for feeding the recording medium to the image forming unit 140, and an operation panel 160. Printer 100 and paper feeding unit 150 are examples of a processing execution apparatus. The recording medium includes papers such as paper and OHP (Over Head Projector) sheets. Here, the case of using paper as an example of the recording medium will be described.

[0018] The image forming unit 140 includes image forming units 20Y, 20M, 20C, and 20K for yellow, magenta, cyan, and black respectively. Here, "Y", "M", "C", and "K" represent yellow, magenta, cyan, and black respectively. Printing data for yellow, magenta, cyan, and black are input into the image forming units 20Y, 20M, 20C, and 20K respectively. Since the image forming units 20Y, 20M, 20C, and 20K only differ in the color of the toner they handle, the image forming unit 20Y for forming a yellow image will be described here.

[0019] The image forming unit 20Y includes an exposure device 21Y, a photosensitive drum 23Y, a charging roller 22Y, a developing device 24Y, a primary transfer roller 25Y, a toner bottle 41Y, and a toner hopper 42Y. The exposure device 21Y receives yellow printing data. The photosensitive drum 23Y is an image carrier. The charging roller 22Y uniformly charges the surface of the photosensitive drum 23Y. The developing device 24Y forms a toner image on the photosensitive drum 23Y. The primary transfer roller 25Y transfers the toner image formed on the photosensitive drum 23Y onto an intermediate transfer belt 30, which is an image carrier, by the action of an electric field force. The drum cleaning blade 27Y removes the toner remaining on the photosensitive drum 23Y.

[0020] The toner bottle 41Y contains yellow toner. The toner bottle 41Y rotates using a toner bottle motor as its drive source and discharges toner to the outside. The toner discharged from the toner bottle 41Y is supplied to the toner hopper 42Y. The toner hopper 42Y supplies toner to the developer unit 24Y in accordance with the amount of toner remaining in the developer unit 24Y, which falls below a predetermined lower limit.

[0021] Around the photoreceptor drum 23Y, the charging roller 22Y, exposure unit 21Y, developer unit 24Y, primary transfer roller 25Y, and drum cleaning blade 27Y are arranged in order along the rotational direction of the photoreceptor drum 23Y.

[0022] The photoreceptor drum 23Y is charged by the charging roller 22Y, and then irradiated with laser light emitted by the exposure device 21Y. The exposure device 21Y exposes the image-corresponding area on the surface of the photoreceptor drum 23Y to form an electrostatic latent image. The developer 24Y develops the electrostatic latent image formed on the photoreceptor drum 23Y with charged toner. Specifically, toner is placed on the electrostatic latent image formed on the photoreceptor drum 23Y by the action of an electric field force, thereby forming a toner image on the photoreceptor drum 23Y. The toner image formed on the photoreceptor drum 23Y is transferred onto the intermediate transfer belt 30, which is an image carrier, by the action of an electric field force using the primary transfer roller 25Y. Toner that remains on the photoreceptor drum 23Y without being transferred is removed from the photoreceptor drum 23Y by the drum cleaning blade 27Y.

[0023] Meanwhile, the intermediate transfer belt 30 is suspended by the drive roller 33 and the driven roller 34 to prevent slack. When the drive roller 33 rotates counterclockwise in Figure 2, the intermediate transfer belt 30 rotates counterclockwise in the figure at a predetermined speed. As the intermediate transfer belt 30 rotates, the driven roller 34 rotates counterclockwise.

[0024] As a result, the image forming units 20Y, 20M, 20C, and 20K sequentially transfer toner images onto the intermediate transfer belt 30. The timing at which each of the image forming units 20Y, 20M, 20C, and 20K transfers toner images onto the intermediate transfer belt 30 is adjusted by detecting reference marks attached to the intermediate transfer belt 30. In this way, yellow, magenta, cyan, and black toner images are superimposed on the intermediate transfer belt 30.

[0025] The toner image formed on the intermediate transfer belt 30 is transferred to the paper by the action of an electric field force by the secondary transfer roller 26, which is a transfer member. The paper, which is transported by the timing roller 31, is transported to the nip section N where the intermediate transfer belt 30 and the secondary transfer roller 26 come into contact. The paper on which the toner image has been transferred is transported to the fixing device 50, where it is heated and pressurized. This melts the toner and fixes it to the paper. After that, the paper is discharged into the output tray 39.

[0026] A belt cleaning blade 28 is provided upstream of the image forming unit 20Y of the intermediate transfer belt 30. The belt cleaning blade 28 removes toner that remains on the intermediate transfer belt 30 without being transferred to the paper.

[0027] When forming a full-color image, the image forming unit 140 drives all of the image forming units 20Y, 20M, 20C, and 20K, but when forming a monochrome image, it drives only one of the image forming units 20Y, 20M, 20C, and 20K. It is also possible to form an image by combining two or more of the image forming units 20Y, 20M, 20C, and 20K. The printer 100 will be described in an example that employs a tandem system equipped with image forming units 20Y, 20M, 20C, and 20K that form four different colors of toner on the paper. Note that the printer 100 may also employ a four-cycle system in which a single photosensitive drum transfers the four colors of toner sequentially onto the paper.

[0028] The paper feeding unit 150 includes a paper feeding cassette 35, an ejection roller 36, a transport roller 32, a timing roller 31, a fuser 50, a paper discharge roller 37, a reversing roller 45, a first reversing transport roller 46, and a second reversing transport roller 47. A transport path 15 is formed connecting the ejection roller 36 to the paper discharge roller 37. The ejection roller 36, transport roller 32, timing roller 31, fuser 50, and paper discharge roller 37 are arranged in this order from bottom to top within the transport path 15. A secondary transfer roller 26 is located between the timing roller 31 and the fuser 50.

[0029] The transport path 15 has a first branching point C1 and a second branching point C2. The first branching point C1 is located between the transport roller 32 and the timing roller 31. The second branching point C2 is located between the fixing device 50 and the paper discharge roller 37. The transport path 15 is connected to the reversal path 16 at the first branching point C1. The reversal path 16 is the path connecting the reversal roller 45 and the first branching point C1. The first reversal transport roller 46 and the second reversal transport roller 47 are arranged in the reversal path 16. The first reversal transport roller 46 is positioned closer to the reversal roller 45 than the second reversal transport roller 47. The reversal path 16 has a third branching point C3 between the reversal roller 45 and the first reversal transport roller 46. A connecting path 17 is formed connecting the transport path 15 and the reversal path 16. The connecting path 17 is the path connecting the second branching point C2 and the third branching point C3. The connection path 17 connects to the transport path 15 at the second branching point C2 and to the reversal path 16 at the third branching point C3.

[0030] The transport path 15 includes a first path P1 between the transport roller 32 and the first branching point C1, a second path P2 between the first branching point C1 and the timing roller 31, and a third path P3 between the fixing device 50 and the paper discharge roller 37.

[0031] Multiple sheets of paper are loaded into the paper feed cassette 35. The paper stored in the paper feed cassette 35 is supplied one sheet at a time to the transport path 15 by the ejection roller 36 attached to the paper feed cassette 35. The paper supplied to the transport path 15 by the ejection roller 36 is transported by the transport roller 32 through the first path P1 and the second path P2 to the timing roller 31.

[0032] The timing roller 31 transports the paper toward the secondary transfer roller 26. As the paper transported by the timing roller 31 passes through the nip section N formed between the secondary transfer roller 26 and the drive roller 33, the toner image formed on the intermediate transfer belt 30 is transferred by the secondary transfer roller 26. The paper passing through the nip section N is then transported to the fuser 50 by the intermediate transfer belt 30 and the secondary transfer roller 26.

[0033] The fuser 50 includes a pressure roller and a heating section. As the paper passes between the pressure roller and the heating section, the toner image formed on the paper is heated and pressurized, thereby fixing the toner image to the paper. The paper transported by the fuser 50 is transported towards either the paper discharge roller 37 or the reversing roller 45. A switching claw provided at the second branching point C2 of the transport path 15 switches whether the paper is transported towards the paper discharge roller 37 or the reversing roller 45. The paper transported from the fuser 50 towards the paper discharge roller 37 is transported to the paper discharge roller 37 via the third path P3. The paper discharge roller 37 discharges the paper transported by the fuser 50 into the paper discharge tray 39.

[0034] The paper transported from the fuser 50 toward the reversing roller 45 is transported to the reversing roller 45 through the portion of the third path P3 from the fuser 50 to the second branching point C2, the connecting path 17, and the portion of the fourth path P4 between the third branching point C3 and the reversing roller 45. The reversing roller 45 transports the paper transported by the fuser 50 toward the output tray 39 until the downstream end of the paper passes the third branching point C3. Then, in response to the downstream end of the paper passing the third branching point C3, the reversing roller 45 reverses its direction of rotation and transports the paper toward the first reversing transport roller 46. The paper transported by the reversing reversing roller 45 is transported toward the first reversing transport roller 46 through the fourth path P4. The first reversing transport roller 46 transports the paper toward the second reversing transport roller 47. The second reversing transport roller 47 transports the paper toward the timing roller 31. The paper transported by the second reversing transport roller 47 is transported to the timing roller 31 through the section of the fourth path P4 from the second reversing transport roller 47 to the first branching point C1 and through the second path P2.

[0035] A paper feed sensor 11 is located in the first path P1. The paper feed sensor 11 detects the paper being transported along the first path P1. A registration sensor 12 is located in the second path P2. The registration sensor 12 detects the paper being transported along the second path P2. A paper discharge sensor 13 is located in the third path P3. The paper discharge sensor 13 detects the paper being transported along the third path P3. The reversal path 16 has a fourth path P4 between the first reversal transport roller 46 and the second reversal transport roller 47. A duplex sensor 14 is located in the fourth path P4. The duplex sensor 14 detects the paper being transported along the fourth path P4.

[0036] The paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are all optical sensors. An optical sensor has a light-emitting part and a light-receiving part, and the light emitted from the light-emitting part is received by the light-receiving part. The amount of light received by the light-receiving part changes depending on whether or not paper is present in the detection area provided between the light-emitting part and the light-receiving part. The optical sensor detects the paper by detecting this change in the amount of light. The optical sensor may be transmissive or reflective. A transmissive optical sensor detects the phenomenon that light emitted from the light-emitting part is blocked by the paper. A reflective optical sensor detects the phenomenon that light emitted from the light-emitting part is reflected by the paper. In this embodiment, the case in which the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are all transmissive optical sensors will be described as an example.

[0037] Figure 3 is a circuit diagram showing an example of the electrical connection relationships of various sensors. Referring to Figure 3, the electrical circuit has the ammeter 19 connected in series with the power supply 18, and the paper feed sensor 11, resist sensor 12, paper discharge sensor 13, and duplex sensor 14 connected in parallel.

[0038] Figure 4 is a block diagram illustrating the hardware configuration of the printer in this embodiment. Referring to Figure 4, the printer 100 includes a main circuit 110, an image forming unit 140, a paper feeding unit 150, and an operation panel 160. The operation panel 160 is the user interface.

[0039] The main circuit 110 includes a CPU 111, a communication interface (I / F) unit 112, a ROM 113, a RAM 114, an HDD 115, and an external storage device 117. The HDD 115 is a high-capacity storage device. A solid-state drive (SSD) may be used instead of the HDD 115. The CPU 111 is connected to the image forming unit 140, the paper feeding unit 150, and the operation panel 160, and controls the entire printer 100.

[0040] The communication interface unit 112 is an interface for connecting the printer 100 to the network. The communication interface unit 112 communicates with computers connected to the network using communication protocols such as TCP (Transmission Control Protocol) or FTP (File Transfer Protocol).

[0041] ROM113 stores the program that the CPU111 executes, or the data necessary to execute that program. RAM114 is used as a workspace when the CPU111 executes the program.

[0042] The control panel 160 includes a display unit 161 and an operation unit 163. The display unit 161 is, for example, a liquid crystal display (LCD) and displays instruction menus for the user, information about acquired image data, etc. Alternatively, any device that displays images, such as an organic EL display, may be used instead of the LCD.

[0043] The operating unit 163 includes a touch panel 165 and a hard key unit 167. The touch panel 165 is capacitive. However, the touch panel 165 is not limited to the capacitive type; other types such as resistive, surface acoustic wave, infrared, and electromagnetic induction can be used. The hard key unit 167 includes a plurality of hard keys. The hard keys are, for example, contact switches.

[0044] The external storage device 117 is controlled by the CPU 111 and has a CD-ROM 118 installed in it. In this embodiment, an example is described in which the CPU 111 executes a program stored in ROM 113. Alternatively, the CPU 111 may control the external storage device 117 to read a program for execution from the CD-ROM 118, store the read program in RAM 114, and then execute it.

[0045] Furthermore, the recording medium for storing the program to be executed by the CPU 111 is not limited to the CD-ROM 118, but may also be a flexible disk, cassette tape, optical disk, semiconductor memory, etc. Optical disks include MO (Magnetic Optical Disc), MD (MiniDisc), and DVD (Digital Versatile Disc). Semiconductor memory includes IC cards, optical cards, mask ROM, and EPROM (Erasable Programmable ROM).

[0046] Furthermore, the CPU 111 may load programs stored in the HDD 115 into the RAM 114 and execute them. Programs stored in the HDD 115 include programs downloaded by the CPU 111 from computers connected to a network such as the Internet, or programs written to the HDD 115 by computers connected to the network. The term "program" here includes not only programs that can be directly executed by the CPU 111, but also source programs, compressed programs, encrypted programs, and so on.

[0047] Figure 5 is a block diagram showing an example of the functions of the CPU in the printer. The functions shown in Figure 5 are realized by the CPU 111 of the printer 100, which executes a malfunction detection program stored in the ROM 113, HDD 115, or CD-ROM 118. Referring to Figure 5, the CPU 111 includes a processing execution unit 51, a batch detection unit 53, a normal determination unit 55, a malfunction determination unit 57, and a notification unit 59.

[0048] The processing execution unit 51 executes predetermined processes. The processing execution unit 51 controls the paper feeding unit 150 to execute multiple processes for transporting paper. The multiple processes for transporting paper include the first to fourth processes. The first process is the process of controlling the paper feeding unit 150 to transport the paper along the first path P1. The second process is the process of controlling the paper feeding unit 150 to transport the paper along the second path P2. The third process is the process of controlling the paper feeding unit 150 to transport the paper along the third path P3. The fourth process is the process of controlling the paper feeding unit 150 to transport the paper along the fourth path P4.

[0049] Specifically, when the processing execution unit 51 executes the first process, it drives the transport roller 32 and transports the paper taken out of the paper feed cassette 35 by the ejection roller 36. The processing execution unit 51 determines that the first process has been executed successfully if the paper is detected by the paper feed sensor 11 from the time Ts1 elapsed since the transport roller 32 was driven until the detection period Te1 has elapsed. The processing execution unit 51 determines that the first process has not been executed successfully and is in a first abnormal state if the paper is not detected by the paper feed sensor 11 even after the time Ts1 elapsed since the transport roller 32 was driven. The first abnormal state is a state in which a malfunction has occurred in the paper feed sensor 11. Furthermore, the processing execution unit 51 determines that the first process has not been executed successfully and is in a second abnormal state if the period during which the paper is detected by the paper feed sensor 11 exceeds the detection period Te1. The second abnormal state is a state in which the paper jams without being transported during the execution of the first process. The detection period Te1 is determined by the paper size and the speed at which the transport roller 32 transports the paper.

[0050] The processing execution unit 51 executes the second process after executing the first process or after executing the fourth process. When the processing execution unit 51 executes the second process after executing the first process, it drives the timing roller 31 to transport the paper passing through the first path P1 through the second path P2. The processing execution unit 51 determines that the second process has been executed successfully if the paper is detected by the registration sensor 12 from the time Ts2 elapsed after the paper is detected by the paper feed sensor 11 until the detection period Te2 has elapsed. The processing execution unit 51 determines that the second process has not been executed successfully and is in a first abnormal state if the paper is not detected by the registration sensor 12 even after the time Ts2 has elapsed since the paper was detected by the paper feed sensor 11. Furthermore, the processing execution unit 51 determines that the second process has not been executed successfully and is in a second abnormal state if the period during which the paper is detected by the registration sensor 12 exceeds the detection period Te2. The detection period Te2 is determined by the time the timing roller 31 starts transporting the paper, the size of the paper, and the speed at which the timing roller 31 transports the paper.

[0051] When the processing execution unit 51 executes the second process after executing the fourth process, it drives the timing roller 31 to transport the paper passing through the fourth path P4 through the second path P2. The processing execution unit 51 determines that the second process has been executed successfully if the paper is detected by the resist sensor 12 from the time Ts5 elapsed after the paper is detected by the duplex sensor 14 until the detection period Te2 has elapsed. The processing execution unit 51 determines that the second process has not been executed successfully and is in a first abnormal state if the paper is not detected by the resist sensor 12 even after the time Ts5 has elapsed since the paper was detected by the duplex sensor 14. Furthermore, the processing execution unit 51 determines that the second process has not been executed successfully and is in a second abnormal state if the period during which the paper is detected by the resist sensor 12 exceeds the detection period Te2.

[0052] When the processing execution unit 51 executes the third process, it drives the paper discharge roller 37 to transport the paper supplied from the fuser 50. The processing execution unit 51 determines that the third process has been executed successfully if the paper is detected by the paper discharge sensor 13 from the time Ts3 elapsed after the timing roller 31 starts transporting the paper until the detection period Te3 has elapsed. The processing execution unit 51 determines that the third process has not been executed successfully and is in a first abnormal state if the paper is not detected by the paper feed sensor 11 even after the time Ts3 has elapsed since the timing roller 31 started transporting the paper. The processing execution unit 51 also determines that the third process has not been executed successfully and is in a second abnormal state if the period during which the paper is detected by the paper discharge sensor 13 exceeds the detection period Te3. The detection period Te3 is determined by the size of the paper and the speed at which the paper discharge roller 37 transports the paper.

[0053] When the processing execution unit 51 executes the fourth process, it drives the reversing roller 45, the first reversing transport roller 46, and the second reversing transport roller 47 to transport the paper through the fourth path P4. The processing execution unit 51 determines that the fourth process has been executed successfully if the paper is detected by the duplex sensor 14 from the time Ts4 elapsed after the reversing roller 45 reverses its rotational direction until the detection period Te4 has elapsed. The processing execution unit 51 determines that the fourth process has not been executed successfully and is in a first abnormal state if the paper is not detected by the duplex sensor 14 even after the time Ts4 has elapsed since the reversing roller 45 reverses its rotational direction. The processing execution unit 51 also determines that the fourth process has not been executed successfully and is in a second abnormal state if the period during which the paper is detected by the duplex sensor 14 exceeds the detection period Te4. The detection period Te4 is determined by the size of the paper and the speed at which the reversing roller 45, the first reversing transport roller 46, and the second reversing transport roller 47 transport the paper.

[0054] The normal operation determination unit 55 detects whether each of the paper feed sensor 11, resist sensor 12, discharge sensor 13, and duplex sensor 14 is operating normally, based on the outputs of the paper feed sensor 11, resist sensor 12, discharge sensor 13, and duplex sensor 14. If the normal operation determination unit 55 detects that each of the paper feed sensor 11, resist sensor 12, discharge sensor 13, and duplex sensor 14 is operating normally, it outputs normal sensor information to the malfunction determination unit 57. The normal sensor information includes sensor identification information for identifying the optical sensor that has been detected to be operating normally.

[0055] The normal operation determination unit 55 detects that the optical sensor is operating normally when it detects an output value that is output when current is flowing through the optical sensor but not when no current is flowing through it. In this embodiment, the value input from the optical sensor to the CPU 111 when no current is flowing through the optical sensor is the same as the output value that the optical sensor outputs when current is flowing through the optical sensor and the light receiving unit is not receiving light.

[0056] In a transmissive optical sensor, light emitted from a light-emitting part is received by a light-receiving part. In a transmissive optical sensor, the light-emitting part emits light when an electric current is flowing, but does not emit light when no electric current is flowing. Therefore, in a transmissive optical sensor, the light-receiving part will not receive light when no electric current is flowing. The normal operation determination unit 55 detects that the optical sensor is operating normally when it outputs an output value indicating that the light-receiving part of the transmissive optical sensor has received light.

[0057] The normal operation determination unit 55 may also detect that the optical sensor is operating normally when it outputs different output values ​​at different times. A through-type optical sensor outputs different output values ​​when paper is positioned between the light-emitting unit and the light-receiving unit and when no paper is positioned between them, and when current is flowing. When no current is flowing, the output value of the through-type optical sensor does not change depending on whether paper is positioned between the light-emitting unit and the light-receiving unit or not.

[0058] The batch detection unit 53 detects a malfunction in any of the paper feed sensor 11, registration sensor 12, paper discharge sensor 13, and duplex sensor 14. The malfunction determination unit 57 detects the first count after the processing execution unit 51 detects an abnormality in any of the multiple processes and interrupts that process. This allows for an appropriate timing for detecting the first count. Furthermore, reducing the frequency of detecting the first count can suppress an increase in the processing load. Alternatively, the batch detection unit 53 may also detect the first count in response to the replacement of any of the paper feed sensor 11, registration sensor 12, paper discharge sensor 13, and duplex sensor 14. In this case as well, the timing for detecting the first count can be appropriately determined. Furthermore, reducing the frequency of detecting the first count can suppress an increase in the processing load.

[0059] As shown in Figure 3, the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are connected in parallel. The voltage applied to the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 is the same. Therefore, the value of the current flowing through the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 is fixed. If there is a malfunction in any of the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, or the duplex sensor 14, current will not flow to the malfunctioning sensor. Therefore, the current value detected by the ammeter 19 will change. A malfunction is when the sensor does not operate normally, and includes cases where the sensor is broken or when the power supply is not connected to the sensor.

[0060] The batch detection unit 53 detects a malfunction in one of the multiple sensors based on the current value measured by the ammeter 19. Here, we will describe the case where the paper feed sensor 11, the registration sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are of the same model. Hereafter, the paper feed sensor 11, the registration sensor 12, the paper discharge sensor 13, and the duplex sensor 14 will be collectively referred to as sensors.

[0061] Figure 6 shows an example of the sensor's current consumption. Referring to Figure 6, the average current consumption of the sensor is 12.0 mA, and the minimum current consumption of the sensor is 9.5 mA.

[0062] Figure 7 shows an example of a reference value for the sum of the current consumption of the four sensors. The reference value is 48mA. The reference value is determined based on the sum of the current consumption values ​​of each of the four sensors. Here, the reference value is the sum of the average values ​​of the current consumption of each of the four sensors.

[0063] Figure 8 shows an example of a threshold value. The threshold value is determined from the reference value and the minimum current consumption of each of the four sensors. The threshold value for a malfunction in one of the four sensors is 38.5 mA. The threshold value for a malfunction in two of the four sensors is 29.0 mA. The threshold value for a malfunction in three of the four sensors is 19.5 mA. The threshold value for a malfunction in all four sensors is 10.0 mA.

[0064] Returning to Figure 5, the batch detection unit 53 compares the current value measured by the ammeter 19 with four judgment thresholds. Based on the comparison result, the batch detection unit 53 determines the number of faulty sensors among the four sensors as the first number. If the batch detection unit 53 determines that none of the four sensors are faulty, it sets the first number to 0. The batch detection unit 53 outputs the first number to the fault determination unit 57.

[0065] The malfunction determination unit 57 receives a first number from the batch detection unit 53 and normal sensor information from the normal determination unit 55. Based on the normal sensor information, the malfunction determination unit 57 determines the number of optical sensors that are not functioning normally among the four optical sensors as the second number. The malfunction determination unit 57 may also determine the second number based on the normal sensor information input from the normal determination unit 55 while at least one of the first to fourth processes is executed multiple times by the processing execution unit 51. Based on the first number and the second number, the malfunction determination unit 57 determines that one or more optical sensors among the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 have a malfunction. If the first number and the second number match, the malfunction determination unit 57 determines that there is a malfunction in the optical sensor that is not detected as functioning normally by the normal determination unit 55. The normal determination unit 55 outputs the determination result to the notification unit 59. The determination result includes sensor identification information for identifying the malfunctioning optical sensor. The malfunction detection unit 57 determines that the ammeter 19 is faulty if the first count and the second count do not match. The malfunction detection unit 57 outputs the determination result to the notification unit 59. The determination result includes sensor identification information for identifying the ammeter 19.

[0066] After the malfunction detection unit 57 determines that the ammeter 19 is malfunctioning, it does not detect the first number. This prevents the malfunction detection unit 57 from detecting a sensor malfunction based on uncertain information, thereby preventing misdiagnosis of a sensor malfunction.

[0067] The notification unit 59 receives the judgment result from the defect judgment unit 57. The notification unit 59 notifies the user of the defective component in accordance with the judgment result. The notification unit 59 displays the defect information on the display unit 161. The defect information includes sensor identification information if the judgment result includes sensor identification information, and information for identifying the ammeter 19 if the judgment result includes device identification information. The defect information may also include a diagram showing the location of the optical sensor identified by the sensor identification information or the ammeter 19 identified by the device identification information. The notification unit 59 may also output the defect information by voice. The notification unit 59 may also send the defect information to the user who manages the printer 100 by email or other means.

[0068] Figure 9 shows an example of the defect detection process. The defect detection process is performed by the CPU 111 of the printer 100 when the CPU 111 executes a defect detection program stored in the ROM 113, HDD 115, or CD-ROM 118. Referring to Figure 9, the CPU 111 sets the variable i to an initial value of 1 (step S01) and proceeds to step S02. The variable i is a value that indicates the number of times steps S06 to S12, which will be described later, will be executed.

[0069] In step S02, all sensor flags are set to NG, and the process proceeds to step S03. Each of the four sensor flags corresponds to a different sensor and indicates the sensor's status. The flags are set to either OK, which indicates that the sensor is functioning normally, or NG, which indicates that the sensor is not functioning correctly.

[0070] In step S03, the current value is acquired, and the process proceeds to step S04. The CPU 111 controls the ammeter 19 and acquires the current value detected by the ammeter 19. In step S04, the first count is determined based on the current value, and the process proceeds to step S05. The CPU 111 determines the first count by comparing the current value with a judgment threshold corresponding to the number of faulty sensors. The first count is the number of faulty optical sensors among the paper feed sensor 11, resist sensor 12, paper output sensor 13, and duplex sensor 14.

[0071] In step S05, it is determined whether the current value is below the threshold Th. The threshold Th is a predetermined value. Here, the threshold Th is defined as the sum of the average current values ​​flowing through the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 when they are operating normally. In this embodiment, the threshold Th is a reference value of 48mA.

[0072] In step S06, an optical sensor is selected, and the process proceeds to step S07. The optical sensor to be processed is selected from among the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14. In step S07, the output value of the optical sensor selected in step S06 is acquired, and the process proceeds to step S08. In step S08, it is determined whether the optical sensor is functioning correctly based on the output value acquired in step S07. It is determined to be functioning correctly if an output value indicating that the optical sensor has received light at the light receiving unit is acquired. If the optical sensor is functioning correctly, the process proceeds to step S09; otherwise, step S09 is skipped, and the process proceeds to step S10. In step S09, the sensor flag is set to OK, and the process proceeds to step S10. The sensor flag corresponding to the optical sensor selected as the processing target in step S06 is set to OK.

[0073] In step S10, it is determined whether or not there is an optical sensor that should be processed next. If there is an optical sensor that was not selected as a processing target in step S06, the process returns to step S06; otherwise, the process proceeds to step S11.

[0074] In step S11, the second number is determined, and the process proceeds to step S12. The second number is the number of sensors whose sensor flag is set to NG. In step S12, it is determined whether the second number is equal to the first number. If the second number is equal to the first number, the process proceeds to step S13; otherwise, the process proceeds to step S14. In step S13, a malfunction is notified, and the process ends. The CPU 111 notifies the user of the malfunction information, which includes the sensor identification information of the optical sensors whose sensor flag is set to NG.

[0075] In step S14, the variable i is incremented, and the process proceeds to step S15. In step S15, it is determined whether the variable i is greater than a predetermined number of times. If the variable i is greater than the predetermined number of times, the process proceeds to step S16; otherwise, the process returns to step S06. The predetermined number of times is a predetermined value. For example, the predetermined number of times is set by the user and stored in the HDD 115. In step S16, a malfunction of the ammeter 19 is notified, and the process ends. Malfunction information indicating that the ammeter 19 is malfunctioning is notified to the user.

[0076] <Examples> Figure 10 shows an example of the state of multiple sensors. In Figure 10, it is shown that the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are all transmissive optical sensors. It is shown that the state of the paper feed sensor 11, the resist sensor 12, and the duplex sensor 14 are all normal, while the state of the paper discharge sensor 13 is faulty.

[0077] Figure 11 shows an example of the state of multiple sensors at a first time point. In Figure 11, the output values ​​and states of the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are shown. It also shows the case where the current value measured by the ammeter 19 is 39 mA.

[0078] The output values ​​of the paper feed sensor 11 and the resist sensor 12 indicate that light is being received by the light receiving unit. The output values ​​of the paper discharge sensor 13 and the duplex sensor 14 indicate that light is not being received by the light receiving unit and that light is being blocked. In the paper feed sensor 11 and the resist sensor 12, output values ​​indicating that light is being received by the light receiving unit are output only when current is flowing. Therefore, it can be determined that the paper feed sensor 11 and the resist sensor 12 are functioning normally.

[0079] When current flows through the paper ejection sensor 13 and paper is present in the third path P3, the output value of the paper ejection sensor 13 indicates that it is not receiving light from the light receiving unit. Furthermore, when the paper ejection sensor 13 is malfunctioning or disconnected and no current flows, the output value of the paper ejection sensor 13 indicates that it is not receiving light from the light receiving unit, regardless of whether paper is present in the third path P3 or not. Therefore, it is not possible to determine whether the paper ejection sensor 13 is functioning normally or not from its output value.

[0080] When current flows through the duplex sensor 14 and paper is present in the fourth path P4, the output value of the duplex sensor 14 indicates that it is not receiving light from the light receiving unit, thus indicating light shielding. Furthermore, when the duplex sensor 14 is malfunctioning or disconnected and no current flows, the output value of the duplex sensor 14 indicates that it is not receiving light from the light receiving unit, regardless of whether paper is present in the fourth path P4 or not. Therefore, it is not possible to determine whether the paper ejection sensor 13 is functioning normally or not from the output value of the duplex sensor 14.

[0081] The second number, determined from the output values ​​of the paper feed sensor 11, the registration sensor 12, the paper discharge sensor 13, and the duplex sensor 14, is 2. On the other hand, the output values ​​and status are shown. Also, since the current value measured by the ammeter 19 is 39mA, the first number is 1. The first number and the second number do not match. Therefore, it can be seen that either the paper discharge sensor 13 or the duplex sensor 14 is functioning normally, and the other is not functioning normally, but it is not possible to determine which one is functioning normally.

[0082] Figure 12 shows an example of the state of multiple sensors at a second time point. The second time point is after the first time point. In Figure 12, the output values ​​and states of the paper feed sensor 11, the resist sensor 12, the paper discharge sensor 13, and the duplex sensor 14 are shown. It also shows the case where the current value measured by the ammeter 19 is 39 mA.

[0083] The output values ​​of the paper feed sensor 11, the resist sensor 12, and the duplex sensor 14 are being received by the light receiving unit. Therefore, it can be determined that the paper feed sensor 11, the resist sensor 12, and the duplex sensor 14 are functioning normally.

[0084] When current flows through the paper ejection sensor 13 and paper is present in the third path P3, the output value of the paper ejection sensor 13 indicates that it is not receiving light from the light receiving unit. Furthermore, when the paper ejection sensor 13 is malfunctioning or disconnected and no current flows, the output value of the paper ejection sensor 13 indicates that it is not receiving light from the light receiving unit, regardless of whether paper is present in the third path P3 or not. Therefore, it is not possible to determine whether the paper ejection sensor 13 is functioning normally or not from its output value.

[0085] The second number, determined from the output values ​​of the paper feed sensor 11, the registration sensor 12, the paper discharge sensor 13, and the duplex sensor 14, is 1. Meanwhile, the output value and status are shown. Also, the current value measured by the ammeter 19 is 39mA, so the first number is 1. Since the first number and the second number match, it is determined that the paper discharge sensor 13 is malfunctioning or broken, etc. Therefore, it is determined that there is a problem with the paper discharge sensor 13.

[0086] <Variation> (1) In this embodiment, the printer 100 has been described as executing the first to fourth processes in sequence. However, the present invention is not limited thereto. The printer 100 may execute each of the processes independently. In this case, each time one of the first to fourth processes is executed, it is determined whether the executed process has completed successfully, and the result of this determination does not affect the other processes.

[0087] (2) In this embodiment, the printer 100 has been described as executing the first to fourth processes as an example. However, the present invention is not limited thereto. The number of processes that the printer 100 executes may be one or more. The printer 100 may be equipped with multiple sensors. For this reason, when the printer 100 executes one process, multiple sensors are provided corresponding to one process.

[0088] (3) Multiple processes only need to be associated with at least one sensor. Multiple sensors may be associated with a single process. The first number is detected from the current value detected by the ammeter 19, and the second number is detected by determining whether each of the multiple sensors is functioning correctly.

[0089] (4) In this embodiment, a printer 100 was given as an example of a processing execution device. The processing execution device is not limited to a printer, but can be any device capable of executing multiple processes and equipped with one or more sensors corresponding to each of the multiple processes. For example, the processing execution device includes a transport device for transporting paper, an image forming device for forming an image on the paper, and a post-processing device for performing post-processing on the paper. Post-processing includes a process for rearranging multiple sheets of paper, a punching process for punching holes in the paper, a stapling process for inserting staples into the paper, a folding process for folding the paper, and a cutting process for cutting the paper.

[0090] (5) In this embodiment, a printer 100 was described as an example of an image forming apparatus, but the image forming apparatus may also be a copier, a laser beam printer, a facsimile machine, or a multifunction device (Multi Function Peripheral) that combines these.

[0091] (6) In this embodiment, a tandem-type color image forming printer 100 was described as an example of an image forming apparatus. The present invention is not limited to this, and may also be an image forming apparatus that forms monochrome images. The configuration and arrangement of the image forming units 20Y, 20M, 20C, 20K, the secondary transfer roller 26, and the fixing device 50 are not limited to this embodiment, and may be other configurations or arrangements.

[0092] <Summary of Embodiments> (Item 1) Multiple sensors and A batch detection unit that detects a first number indicating the number of faulty sensors among a plurality of sensors, For each of the multiple sensors, a normal operation determination unit is provided to detect whether the sensor is operating normally based on the output value of the sensor. A processing execution device comprising: a malfunction determination unit that determines one or more malfunctioning sensors from among a plurality of sensors based on a second number, which is the total number of sensors that are not detected to be operating normally by the normal determination unit, and the first number.

[0093] In this scenario, a first number indicating the number of faulty sensors among multiple sensors is detected. For each of the multiple sensors, it is detected whether the sensor is functioning normally based on the sensor's output value. Based on the second number, which is the total number of sensors that are not detected as functioning normally, and the first number, one or more faulty sensors are determined from among the multiple sensors. In some cases, it may not be possible to determine whether a sensor is functioning normally from the output values ​​of each of the multiple sensors. Since one or more faulty sensors are determined based on the first and second numbers, the faulty sensor can be accurately identified. As a result, a processing execution device that can detect sensor faults while reducing manufacturing costs can be provided.

[0094] (Item 2) The processing execution device according to Item 1, wherein the malfunction determination unit determines that there is a malfunction in the sensor that the normal operation determination unit has not detected as being in normal operation when the first number and the second number match.

[0095] According to this procedure, if the first and second counts match, a sensor that does not detect normal operation is determined to be faulty. Therefore, by comparing the two pieces of information, the first and second counts, the faulty sensor can be identified.

[0096] (Item 3) Multiple sensors are connected to a common connection line, The system further includes an ammeter for detecting the current flowing through the aforementioned connecting wire, The batch detection unit determines the first number based on the current value detected by the ammeter, according to the processing execution device according to item 1 or 2.

[0097] In this scenario, the first number is determined based on the current value flowing through a shared connection line shared by multiple sensors. Therefore, a single ammeter can detect a malfunction in any of the multiple sensors.

[0098] (Item 4) The processing execution device according to Item 3, further comprising a fault determination unit that determines that the ammeter is malfunctioning if the first number and the second number do not match.

[0099] Following this procedure allows for the detection of a malfunction in the ammeter.

[0100] (Item 5) If the fault determination unit determines that the ammeter is malfunctioning, the batch detection unit does not detect the first number, the processing execution device according to Item 4.

[0101] Following this procedure, if it is determined that the ammeter is faulty, the first value will not be detected. Therefore, since the sensor fault will not be detected based on uncertain information, it is possible to prevent the sensor fault from being incorrectly determined.

[0102] (Item 6) The processing execution device according to any one of Items 1 to 5, wherein the normal determination unit detects that a sensor is operating normally when it detects an output value that is output by a sensor through which current is flowing but not by a sensor through which no current is flowing.

[0103] In this scenario, a sensor is detected as functioning correctly when it detects an output value that is emitted by a sensor with current flowing through it, but not by a sensor with no current flowing through it. Therefore, it is possible to accurately detect whether the sensor is functioning correctly.

[0104] (Item 7) The processing execution device according to any one of Items 1 to 6, wherein the normal determination unit detects that each of the plurality of sensors that outputs different output values ​​at different times is operating normally.

[0105] Following this procedure, sensors that output different values ​​at different times are detected as functioning correctly. Since sensors with current flowing are detected as functioning correctly, sensors with no current flowing can be detected as faulty.

[0106] (Item 8) The system further comprises a processing execution unit that performs processing using the output values ​​of a plurality of sensors, The batch detection unit detects the first number after the processing execution unit has interrupted the execution of the processing, according to any one of items 1 to 7.

[0107] In this scenario, the first count is detected after the execution of processing using the output values ​​of multiple sensors is interrupted. Therefore, the timing of detecting the first count can be appropriately determined. In addition, the frequency of detecting the first count can be reduced, thereby suppressing an increase in the processing load.

[0108] (Item 9) The processing execution device according to any one of items 1 to 8, wherein the batch detection unit detects the first number in accordance with the replacement of any of the plurality of sensors.

[0109] In this scenario, the first count is detected when any of the multiple sensors are replaced. Therefore, the timing of detecting the first count can be appropriately determined. In addition, by reducing the frequency of detecting the first count, the increase in processing load can be suppressed.

[0110] (Item 10) The system further comprises a processing execution unit that sequentially executes a plurality of processes corresponding to each of the plurality of sensors, The processing execution unit, if an error is detected in any of the multiple processes, does not execute one or more subsequent processes, as described in any of items 1 to 9.

[0111] In this scenario, multiple processes corresponding to multiple sensors are executed sequentially, and if an error is detected in any of these processes, one or more subsequent processes will not be executed. Therefore, when multiple processes are executed sequentially, it is possible to detect malfunctions in each of the multiple sensors corresponding to each of the processes.

[0112] (Item 11) An image forming apparatus equipped with a processing execution device as described in any of Items 1 to 10.

[0113] Following this approach, it will be possible to provide an image forming apparatus that can detect sensor malfunctions while reducing manufacturing costs.

[0114] (Item 12) A method for determining a malfunction that is performed by a processing execution device equipped with multiple sensors, A batch detection step for detecting a first number indicating the number of faulty sensors among a plurality of sensors, A normal operation determination step for each of the multiple sensors, which detects whether the sensor is operating normally based on the output value of the sensor, A malfunction determination method comprising: a malfunction determination step in which, based on a second number which is the total number of sensors that are not detected to be operating normally in the normal determination step, and the first number, one or more of the sensors that are malfunctioning are determined from among the plurality of sensors.

[0115] Following this approach, it becomes possible to provide a fault detection method that can detect sensor malfunctions while reducing manufacturing costs.

[0116] (Item 13) A malfunction determination program executed by a computer that controls a processing execution device equipped with multiple sensors, A batch detection step for detecting a first number indicating the number of faulty sensors among a plurality of sensors, A normal operation determination step for each of the multiple sensors, which detects whether the sensor is operating normally based on the output value of the sensor, A malfunction determination program that causes the computer to perform a malfunction determination step, which determines one or more malfunctioning sensors from among the plurality of sensors based on a second number, which is the total number of sensors that are not detected to be operating normally in the normal determination step, and the first number.

[0117] Following this approach, it becomes possible to provide a fault detection program that can detect sensor malfunctions while reducing manufacturing costs.

[0118] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0119] 100 Printer, 110 Main circuit, 111 CPU, 112 Communication I / F unit, 113 ROM, 114 RAM, 115 HDD, 117 External storage device, 118 CD-ROM, 140 Image forming unit, 150 Paper feeding unit, 160 Operation panel, 161 Display unit, 163 Operation unit, 165 Touch panel, 167 Hard key unit, 11 Paper feed sensor, 12 Resist sensor, 13 Paper ejection sensor, 14 Duplex sensor, 15 Transport path, 16 Reversal path, 17 Connection path, 18 Power supply, 19 Ammeter, 20Y, 20M, 20C, 20K Image forming unit, 26 Secondary transfer roller, 30 Intermediate transfer belt, 31 Timing roller, 32 Transport roller, 33 Drive roller, 34 Driven roller, 35 Paper feed cassette, 36 Ejection roller, 37 39 Paper output roller, 45 Paper output tray, 46 Reversing roller, 47 First reversing transport roller, 50 Fixing device, 51 Processing execution unit, 53 Batch detection unit, 55 Normal judgment unit, 57 Malfunction judgment unit, 59 Notification unit, C1 First branching point, C2 Second branching point, C3 Third branching point, N Nip section, P1 First path, P2 Second path, P3 Third path, P4 Fourth path.

Claims

1. Multiple sensors, A batch detection unit that detects a first number indicating the number of faulty sensors among a plurality of sensors, For each of the multiple sensors, a normal operation determination unit is provided to detect whether the sensor is operating normally based on the output value of the sensor. A processing execution device comprising: a malfunction determination unit that determines one or more malfunctioning sensors from among a plurality of sensors based on a second number, which is the total number of sensors that the normal determination unit does not detect as operating normally, and the first number.

2. The processing execution device according to claim 1, wherein the malfunction determination unit determines that there is a malfunction in the sensor that the normal operation determination unit has not detected as being in normal operation when the first number and the second number match.

3. Multiple of the aforementioned sensors are connected to a common connection line. The system further includes an ammeter for detecting the current flowing through the aforementioned connecting wire, The processing execution device according to claim 1, wherein the batch detection unit determines the first number based on the current value detected by the ammeter.

4. The processing execution device according to claim 3, further comprising a fault determination unit that determines that the ammeter is malfunctioning if the first number and the second number do not match.

5. If the fault determination unit determines that the ammeter is malfunctioning, the batch detection unit does not detect the first number, as described in claim 4.

6. The processing execution device according to claim 1, wherein the normal determination unit detects that a sensor is operating normally when it detects an output value that is output by a sensor through which current is flowing but not by a sensor through which no current is flowing.

7. The processing execution device according to claim 1, wherein the normal determination unit detects that each of the plurality of sensors that outputs different output values ​​at different times is operating normally.

8. The system further includes a processing execution unit that performs processing using the output values ​​of multiple sensors, The processing execution device according to claim 1, wherein the batch detection unit detects the first number after the processing execution unit has interrupted the execution of the processing.

9. The processing execution device according to claim 1, wherein the batch detection unit detects the first number in response to any of the multiple sensors being replaced.

10. The system further includes a processing execution unit that sequentially executes multiple processes corresponding to each of the multiple sensors, The processing execution device according to claim 1, wherein the processing execution unit does not execute one or more subsequent processes if an error is detected in any of the plurality of processes.

11. An image forming apparatus comprising a processing execution device according to any one of claims 1 to 10.

12. A method for determining a malfunction that is performed by a processing execution device equipped with multiple sensors, A batch detection step for detecting a first number indicating the number of faulty sensors among a plurality of sensors, A normal operation determination step for each of the multiple sensors, which detects whether the sensor is operating normally based on the output value of the sensor, A malfunction determination method comprising: a malfunction determination step in which, based on a second number which is the total number of sensors that are not detected to be operating normally in the normal determination step, and the first number, one or more of the sensors that are malfunctioning are determined from among the plurality of sensors.

13. A malfunction detection program executed by a computer that controls a processing execution device equipped with multiple sensors, A batch detection step for detecting a first number indicating the number of faulty sensors among a plurality of sensors, A normal operation determination step for each of the multiple sensors, which detects whether the sensor is operating normally based on the output value of the sensor, A malfunction determination program that causes the computer to perform a malfunction determination step, which determines one or more malfunctioning sensors from among the plurality of sensors based on a second number, which is the total number of sensors that are not detected to be operating normally in the normal determination step, and the first number.

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