Image forming apparatus, deterioration state determination method, and program

Abstract

To appropriately determine a state of deterioration of a detector element due to the influence of electromagnetic wave noise, despite individual difference in tolerance against the electromagnetic wave noise.SOLUTION: An image forming apparatus 1 comprises: a detector element 18 that detects a specific state and outputs a predetermined output signal SIG; and a determination unit 62 that, according to a state of the output signal SIG, determines a state of deterioration of the detector element 18 until the timing of replacement of the detector element 18 is reached. For example, the determination unit 62 measures the tolerance of the detector element 18 against electromagnetic wave noise on the basis of the output signal SIG, and determines the state of deterioration of the detector element 18 on the basis of the tolerance. For example, the determination unit 62 determines the state of deterioration of the detector element 18 on the basis of a state from when the detector element 18 detects the specific state until when the output signal SIG is settled.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, a deterioration state determining method, and a program. [Background technology]

[0002] When electrical equipment operates, electromagnetic noise is generated. Electromagnetic noise can change the characteristics of electrical components or damage them. Therefore, electromagnetic noise is one of the factors that cause electrical equipment to malfunction. Image forming devices such as MFPs (Multifunction Peripherals) also generate electromagnetic noise during operation. In order to prevent the image forming device from affecting other products in the vicinity, standards are set for the image forming device to suppress the electromagnetic noise to a specified level or less. In addition, standards are set for the image forming device's tolerance to electromagnetic noise so that the image forming device does not malfunction or become damaged due to electromagnetic noise from other products.

[0003] Electrical components mounted on an image forming apparatus also generate electromagnetic noise during operation, or are affected by external electromagnetic noise. Depending on the electrical component, the characteristics may gradually change due to the influence of external electromagnetic noise. Even though the characteristics change little by little from the initial state, the user does not notice the change in the characteristics of the components and continues to use the image forming apparatus. When a user uses the image forming apparatus under such circumstances, electrical components may malfunction due to the influence of electromagnetic noise. For example, if an electrical component malfunctions in an image forming apparatus, the execution of a job cannot be completed normally.

[0004] For example, the resistance of electrical components such as sensors to electromagnetic noise is determined by whether they malfunction. Whether they malfunction or not depends on whether the characteristics of the electrical components change due to the effects of electromagnetic noise. Therefore, in order to prevent electrical components from malfunctioning, it is necessary to evaluate the characteristics of the electrical components.

[0005] Conventionally, in an image forming device composed of multiple components, a technology has been proposed in which noise of a predetermined frequency generated by the components is detected, the intensity of the noise is compared with a predetermined reference value stored in advance, and the status of other components (control circuits) is determined and reported based on the comparison results (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-102724 Summary of the Invention [Problem to be solved by the invention]

[0007] Each part has individual differences in resistance to electromagnetic noise. The conventional technology of Patent Document 1 detects noise of a specific frequency and compares it with a specific reference value to determine the state of the part. However, the specific reference value does not reflect the individual differences between parts. Therefore, even if it is determined that there is a possibility of a failure, there may be cases where the failure does not actually occur. Also, even if it is determined that there is no possibility of a failure, there may be cases where the part actually malfunctions due to a change in the part's characteristics, leading to a failure.

[0008] Therefore, in order to solve the above-mentioned problems in the conventional art, the present invention aims to provide an image forming apparatus, a deterioration state determination method, and a program that are capable of appropriately determining the deterioration state of parts caused by the effects of electromagnetic noise, even if there are individual differences in tolerance to electromagnetic noise. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the invention of claim 1 is an image forming apparatus comprising a detector element having a receiving unit that receives a specific signal and an output unit that outputs a predetermined output value based on the specific signal received by the receiving unit, and a judgment unit that judges the deterioration state of the detector element to the point where it requires replacement based on the output status from the output unit.

[0010] The invention of claim 2 is characterized in that, in the image forming apparatus of claim 1, the detector element outputs an output signal which becomes a predetermined output value when it detects a specific state, and the judgment unit judges the deterioration state of the detector element until it reaches the time for replacement depending on the state of the output value output as the output signal.

[0011] The invention of claim 3 is characterized in that, in the image forming apparatus of claim 1, the judgment unit measures the tolerance of the detection element to electromagnetic noise based on the output value, and judges the deterioration state of the detection element based on the tolerance.

[0012] The invention of claim 4 is characterized in that, in the image forming apparatus of claim 2, the judgment unit judges the deterioration state of the detection element based on the state from when the detection element detects the specific state to when the output value is determined.

[0013] The invention of claim 5 is an image forming apparatus of claim 1, characterized in that the judgment unit judges the deterioration state of the detection element by distinguishing between a quasi-failure state and a failure state of the detection element.

[0014] The invention of claim 6 is characterized in that, in the image forming apparatus of claim 2, the detection element has a light-projecting section and a light-receiving section, and the light-receiving section outputs the output signal according to the amount of light received when it receives light irradiated from the light-projecting section.

[0015] The invention of claim 7 is characterized in that, in the image forming apparatus of claim 6, the judgment unit repeatedly samples a logical value based on the output signal output from the light receiving unit at a predetermined period, and judges the deterioration state of the detection element based on a logical change until the logical value indicates a predetermined value multiple times in succession.

[0016] The invention of claim 8 is characterized in that in the image forming apparatus of claim 7, the judgment unit counts the number of mismatches in which the logical value does not match the specified value during a period until the logical value indicates a specified value multiple times in succession, and judges the deterioration state of the detection element based on the number of mismatches.

[0017] The invention of claim 9 is characterized in that in the image forming apparatus of claim 7, the judgment unit counts the number of times the logical value is inverted during a period until the logical value indicates a predetermined value multiple times in succession, and judges the deterioration state of the detection element based on the number of inversions.

[0018] The invention of claim 10 is characterized in that, in the image forming apparatus of claim 7, the judgment unit calculates a mismatch probability in which the logical value does not match the specified value during a period until the logical value indicates the specified value multiple times in succession, and judges the deterioration state of the detection element based on the mismatch probability.

[0019] The invention of claim 11 is characterized in that, in the image forming apparatus of claim 7, the judgment unit repeats a detection process multiple times to detect a logical change until the logical value indicates a predetermined value multiple times in succession, calculates a mismatch probability in which the logical value does not match the predetermined value in multiple detection processes, and judges the deterioration state of the detection element based on the mismatch probability.

[0020] The invention of claim 12 is characterized in that, in the image forming apparatus of claim 6, the judgment unit measures the output current flowing to the light receiving unit and judges the deterioration state of the detection element based on the measurement result of the output current.

[0021] The invention of claim 13 is an image forming apparatus of claim 12, characterized in that the judgment unit changes the current flowing to the light-projecting unit, repeatedly samples a logical value based on the output signal output from the light-receiving unit at a predetermined period, and measures the output current flowing to the light-receiving unit based on the logical change until the logical value indicates a predetermined value multiple times in succession.

[0022] The invention of claim 14 is an image forming apparatus of claim 12, characterized in that the judgment unit changes a pull-up resistor connected to the light-receiving unit, repeatedly samples a logical value based on the output signal output from the light-receiving unit at a predetermined period, and measures the output current flowing to the light-receiving unit based on the logical change until the logical value indicates a predetermined value multiple times in succession.

[0023] The invention of claim 15 is an image forming apparatus of claim 7, characterized in that the judgment unit repeatedly samples a logical value based on the output signal output from the light receiving unit at a predetermined period, and if the number of mismatches between the logical value and the predetermined value during the period until the logical value indicates a predetermined value multiple times in succession is equal to or greater than a predetermined number, measures the output current flowing to the light receiving unit, and judges the deterioration state of the detection element based on the measurement result of the output current.

[0024] The invention of claim 16 is an image forming apparatus as recited in claim 1, further comprising a communication unit which communicates with an external device, and a decision unit which decides whether to determine the deterioration state of the detection element based on information received from the external device, and when the decision unit decides to determine the deterioration state of the detection element, the decision unit determines the deterioration state of the detection element until it reaches the time for replacement depending on the output status from the output unit.

[0025] The invention of claim 17 is the image forming apparatus of claim 1, further comprising a decision unit which detects electromagnetic noise and decides whether to judge the deterioration state of the detection element, and when the decision unit decides to judge the deterioration state of the detection element, the decision unit judges the deterioration state of the detection element until it needs to be replaced depending on the output status from the output unit.

[0026] The invention of claim 18 is an image forming apparatus according to claim 6, further comprising a life extension processing unit that performs life extension processing of the detection element, wherein the judgment unit judges whether or not life extension processing of the detection element is possible based on the deterioration state of the detection element, and the life extension processing unit performs the life extension processing of the detection element when the judgment unit judges that life extension processing of the detection element is possible.

[0027] The invention of claim 19 is characterized in that, in the image forming apparatus of claim 18, the life extension processing unit performs life extension processing of the detection element by increasing the current flowing to the light-projecting unit.

[0028] The invention of claim 20 is characterized in that, in the image forming apparatus of claim 18, the life extension processing unit performs life extension processing of the detection element by increasing the pull-up resistance connected to the light receiving unit.

[0029] The invention of claim 21 is a deterioration state determination method for determining the deterioration state of a detector element in an image forming apparatus equipped with a detector element that outputs an output signal, characterized in that the deterioration state of the detector element until it reaches the time for replacement is determined depending on the state of the output signal.

[0030] The invention of claim 22 is a program executed in an image forming apparatus having a detector element that outputs an output signal, characterized in that it causes the image forming apparatus to execute a step of determining a deterioration state of the detector element until it reaches the time for replacement depending on the state of the output signal. Effect of the Invention

[0031] According to the present invention, even if there are individual differences in resistance to electromagnetic noise, it is possible to appropriately determine the deterioration state of a detection element caused by the influence of electromagnetic noise. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 illustrates an example of the configuration of an image forming apparatus. [Diagram 2] FIG. 11 is a block diagram showing an example of a configuration for determining a deterioration state of a detector element. [Diagram 3] 11A and 11B are diagrams illustrating an example of a change in the characteristics of a detector element. [Figure 4] FIG. 13 is a diagram showing a signal output from a comparator. [Diagram 5] FIG. 5 is a diagram showing the sampling results of the signal shown in FIG. [Figure 6] 11 is a diagram illustrating an example of a determination content by a determination unit. FIG. [Figure 7] 10 is a flowchart illustrating an example of a processing procedure performed by the image forming apparatus. [Figure 8] 13 is a flowchart illustrating an example of a detailed procedure of a determination process. [Figure 9] 13A and 13B are diagrams illustrating an example of a logical determination when a process for determining that a logical value has been determined is performed multiple times. [Figure 10] 10 is a flowchart illustrating an example of a processing procedure performed by the image forming apparatus. [Figure 11] 13 is a flowchart illustrating an example of a detailed procedure of a determination process. [Figure 12] FIG. 13 is a diagram illustrating an example of estimating an output current based on the number of mismatch occurrences. [Figure 13]10 is a flowchart illustrating an example of a processing procedure performed by the image forming apparatus. [Figure 14] FIG. 2 is a diagram illustrating an example of a configuration in which a plurality of image forming apparatuses and a server apparatus can communicate with each other. [Figure 15] FIG. 11 is a block diagram showing an example of a configuration for determining a deterioration state of a detector element. [Figure 16] FIG. 11 is a block diagram showing an example of a configuration for determining a deterioration state of a detector element. [Figure 17] FIG. 11 is a block diagram showing an example of a configuration for determining a deterioration state of a detector element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, elements common to each other are designated by the same reference numerals, and redundant description thereof will be omitted.

[0034] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 shown in FIG. 1 executes a print job designated by a user to print and output an image on a sheet 9 such as printing paper. For example, the image forming apparatus 1 forms an image on the sheet 9 by an electrophotographic method. The image forming apparatus 1 is also capable of forming a color image by a tandem method. The image forming apparatus 1 includes a conveying section 2, an image forming section 3, and a fixing section 4 inside the apparatus body. The image forming apparatus 1 conveys sheets 9 stored in a paper feed cassette 8 at the bottom one by one, forms a color image or a monochrome image on the sheet 9, and discharges the sheet 9 from an outlet 15 at the top onto a paper discharge tray 16. The image forming apparatus 1 also includes a control section 7 inside the apparatus body. The control section 7 controls the operations of each section, such as the conveying section 2, the image forming section 3, and the fixing section 4.

[0035] The transport section 2 has a paper feed cassette 8, a pickup roller 10, a paper feed section 11, a transport path 12, a registration section 13, and a secondary transfer section 14. The paper feed cassette 8 is a container that stores a stack of sheets 9 such as printing paper. The pickup roller 10 takes out the topmost sheet 9 of the stack of sheets 9 stored in the paper feed cassette 8 and sends it to the paper feed section 11. The paper feed section 11 takes out only the topmost sheet 9 from the one or more sheets 9 sent out by the pickup roller 10 and supplies it to the transport path 12 downstream.

[0036] The conveying path 12 is a path for conveying the sheet 9 in the conveying direction indicated by the arrow F2. The sheet 9 sent to the conveying path 12 by the paper feed unit 11 is subjected to skew correction in the registration unit 13. For example, the registration unit 13 includes a pair of timing rollers. The registration unit 13 corrects the skew of the sheet 9 by abutting the leading edge of the sheet 9 against the nip portion of the pair of timing rollers. After correcting the skew of the sheet 9, the registration unit 13 holds the leading edge of the sheet 9 in the nip portion of the pair of timing rollers. When the leading edge of the sheet 9 is held in the nip portion of the pair of timing rollers, the conveying unit 2 temporarily stops conveying the sheet 9. The conveying unit 2 drives the pair of timing rollers in accordance with the timing at which the toner image formed by the image forming unit 3 moves to the secondary transfer unit 14, and conveys the sheet 9 toward the secondary transfer unit 14. When the sheet 9 passes through the nip portion of the secondary transfer unit 14, the toner image is transferred to the surface of the sheet 9. The sheet 9 onto which the toner image has been transferred is then subjected to a fixing process when passing through the fixing unit 4. The fixing unit 4 fixes the toner image to the sheet 9 by subjecting the sheet 9 to a heat treatment and a pressure treatment as it is conveyed. The sheet 9 is then discharged from the discharge port 15 onto the paper discharge tray 16.

[0037] The image forming unit 3 forms toner images of four colors, namely, Y (yellow), M (magenta), C (cyan), and K (black), and transfers the toner images of the four colors simultaneously to the sheet 9 passing through the secondary transfer unit 14. The image forming unit 3 includes a plurality of toner bottles 19 (19Y, 19M, 19C, 19K), a plurality of image units 20 (20Y, 20M, 20C, 20K), a plurality of exposure units 25 (25Y, 25M, 25C, 25K), and a transfer unit 30. Each of the plurality of toner bottles 19 (19Y, 19M, 19C, 19K) corresponds to a respective color. Also, each of the plurality of image units 20 (20Y, 20M, 20C, 20K) also corresponds to a respective color. Also, each of the plurality of exposure units 25 (25Y, 25M, 25C, 25K) also corresponds to a respective color.

[0038] The transfer unit 30 is a unit in which a pair of rollers 31, 32, an intermediate transfer belt 33, primary transfer rollers 34 (34Y, 34M, 34C, 34K), and a cleaning section 35 are integrally assembled. The pair of rollers 31, 32 are arranged at a predetermined interval in the horizontal direction. The intermediate transfer belt 33 is an endless belt, and is arranged in a state of being hung on the pair of rollers 31, 32. The primary transfer rollers 34 (34Y, 34M, 34C, 34K) are arranged at positions facing each image unit 20 on the inner side of the intermediate transfer belt 33. The cleaning section 35 removes toner remaining on the surface of the intermediate transfer belt 33.

[0039] Of the pair of rollers 31 and 32, one roller 31 is a drive roller that is attached to a drive shaft provided inside the main body of the apparatus and rotates. The roller 31 circulates the intermediate transfer belt 33 in the direction of the arrow F1 when the drive shaft is rotated. The other roller 32 is attached to a driven shaft provided inside the main body of the apparatus and rotates in accordance with the circulating movement of the intermediate transfer belt 33. The pair of rollers 31 and 32 are installed at positions spaced apart from each other by a predetermined distance inside the main body of the apparatus while applying a certain tension to the intermediate transfer belt 33. The roller 31 is installed at a position facing the secondary transfer unit 14 by being attached to the drive shaft inside the main body of the apparatus. The roller 31 applies a pressing force to the intermediate transfer belt 33 while sandwiching the intermediate transfer belt 33 between the roller 31 and the secondary transfer unit 14. Then, roller 31 sandwiches and presses sheet 9 transported from registration section 13 between intermediate transfer belt 33 and secondary transfer section 14, thereby secondarily transferring the toner image formed on the surface of intermediate transfer belt 33 onto sheet 9.

[0040] The cleaning unit 35 is held in a state of contacting the surface of the intermediate transfer belt 33 at a position facing the roller 32. The cleaning unit 35 removes toner remaining on the surface of the intermediate transfer belt 33 which circulates in the direction of the arrow F1. For example, the cleaning unit 35 includes a cleaning member such as a cleaning blade or a cleaning brush. The cleaning unit 35 brings the cleaning member into contact with the surface of the intermediate transfer belt 33.

[0041] Imaging units 20Y, 20M, 20C, and 20K corresponding to each color are provided below transfer unit 30. Exposure units 25Y, 25M, 25C, and 25K corresponding to each color are provided below each imaging unit 20Y, 20M, 20C, and 20K. Toner bottles 19Y, 19M, 19C, and 19K are disposed above transfer unit 30 and supply toner of each color to each imaging unit 20Y, 20M, 20C, and 20K.

[0042] The imaging units 20Y, 20M, 20C, and 20K have the same configuration, and only differ in the color of the toner they use. That is, each imaging unit 20Y, 20M, 20C, and 20K is a unit that includes an image carrier 21, a charging unit 22, a developing unit 23, and a cleaning blade 24, which are integrally assembled. The image carrier 21 is configured as a photosensitive drum. The charging unit 22, the developing unit 23, and the cleaning blade 24 are disposed around the image carrier 21. In the following, when it is not necessary to distinguish between the imaging units 20Y, 20M, 20C, and 20K, they may be collectively referred to as imaging units 20.

[0043] The image carrier 21 has a photosensitive layer on the surface of the photoreceptor drum. The image carrier 21 rotates in a rightward direction (clockwise direction) while in contact with the intermediate transfer belt 33 to which a transfer pressure is applied by the primary transfer roller 34 of the transfer unit 30. A cleaning blade 24, a charging unit 22, and a developing unit 23 are arranged around the image carrier 21 along the rotation direction. The charging unit 22 has a charging roller that contacts the surface of the image carrier 21. The charging unit 22 charges the surface of the image carrier 21 to a predetermined charge. The exposure unit 25 exposes the photosensitive layer charged by the charging unit 22 based on image data. As a result, the exposure unit 25 forms an electrostatic latent image on the surface of the image carrier 21. The developing unit 23 contains toner supplied from the toner bottle 19, and supplies the charged toner by stirring the carrier and toner to the surface of the image carrier 21. As a result, the developing unit 23 develops the electrostatic latent image with toner, forming a toner image on the surface of the image carrier 21. The toner image formed on the image carrier 21 is primarily transferred to the intermediate transfer belt 33 at a position where it comes into contact with the intermediate transfer belt 33. A bias voltage having a polarity opposite to that of the charged toner image formed on the surface of the image carrier 21 is applied to the primary transfer roller 34. The primary transfer roller 34 primarily transfers the toner image formed on the surface of the image carrier 21 to the intermediate transfer belt 33 by electrostatic force due to the bias voltage.

[0044] Each of the imaging units 20Y, 20M, 20C, and 20K cooperates with the respective primary transfer rollers 34Y, 34M, 34C, and 34K to perform primary transfer while sequentially superimposing the toner images of each color onto the intermediate transfer belt 33 which circulates in the direction of the arrow F1. Therefore, when the intermediate transfer belt 33 passes the position of the most downstream imaging unit 20K, a color image in which the toner images of four colors are superimposed is formed on the surface of the intermediate transfer belt 33. When a monochrome image is formed on the sheet 9, the imaging units 20Y, 20M, and 20C do not operate, and only the imaging unit 20K corresponding to K (black) operates to form a monochrome image using only K toner on the intermediate transfer belt 33.

[0045] The toner image formed on the intermediate transfer belt 33 comes into contact with the sheet 9 transported by the transport unit 2 as it passes a position facing the secondary transfer unit 14, and is secondarily transferred onto the surface of the sheet 9. The secondary transfer unit 14 is provided at a position facing the roller 31 across the intermediate transfer belt 33. When the toner image primarily transferred onto the intermediate transfer belt 33 comes into contact with the sheet 9, a bias voltage of the opposite polarity to that of the charged toner is applied to the secondary transfer unit 14. This allows the toner image to be secondarily transferred onto the sheet 9.

[0046] Even after the toner image is secondarily transferred to the sheet 9 at the secondary transfer unit 14, some toner may remain on the surface of the intermediate transfer belt 33. Such residual toner circulates together with the intermediate transfer belt 33 while remaining attached to the surface of the intermediate transfer belt 33. Then, when the residual toner passes the position of the cleaning unit 35, the cleaning member provided in the cleaning unit 35 removes the residual toner from the surface of the intermediate transfer belt 33.

[0047] In each of the imaging units 20Y, 20M, 20C, and 20K, even after the toner image formed on the image carrier 21 is primarily transferred to the intermediate transfer belt 33, toner may remain on the surface of the image carrier 21. Such residual toner advances toward the cleaning blade 24 as the image carrier 21 rotates, and is removed from the surface of the image carrier 21 by the cleaning blade 24.

[0048] A sheet detection sensor 17a and a loop detection sensor 17b are provided in the conveying path 12 along which the sheet 9 is conveyed. The sheet detection sensor 17a is provided in a position adjacent to the conveying path 12 between the registration unit 13 and the secondary transfer unit 14. The sheet detection sensor 17a is a sensor that detects the passage of the sheet 9 downstream of the registration unit 13. The loop detection sensor 17b is provided in a position adjacent to the conveying path 12 between the secondary transfer unit 14 and the fixing unit 4. The loop detection sensor 17b is a sensor that detects whether or not an appropriate loop (flexure) is formed in the sheet 9 guided to the fixing unit 4 at a predetermined position upstream of the fixing unit 4. Both the sheet detection sensor 17a and the loop detection sensor 17b are detection elements 18 designed to output an output signal indicating a predetermined output value when a specific state in the image forming apparatus 1 is detected.

[0049] FIG. 1 shows an example in which the image forming apparatus 1 is equipped with two detector elements 18. However, the number of detector elements 18 mounted on the image forming apparatus 1 is not limited to two. That is, the image forming apparatus 1 is provided with many detector elements 18 for detecting various states in the image forming apparatus 1. All of the many detector elements 18 are composed of electrical components. Therefore, the characteristics of the detector elements 18 gradually change due to the influence of electromagnetic noise. If the characteristics change, the detector elements 18 may malfunction. If the detector elements 18 malfunction while the image forming apparatus 1 is executing a job, it may cause troubles such as jamming or errors. Therefore, the image forming apparatus 1 of this embodiment is configured to determine the deterioration state of the detector elements 18 due to the influence of electromagnetic noise. Below, a detailed description will be given of a configuration example for determining the deterioration state of the detector elements 18.

[0050] FIG. 2 is a block diagram showing an example of a configuration for determining the deterioration state of the detection element 18. The detection element 18 of this embodiment is configured by a photointerrupter, which is, for example, a transmission type photosensor. The detection element 18 has a light-projecting unit 28 and a light-receiving unit 29. The light-projecting unit 28 is configured by a light-emitting element such as an LED. The light-receiving unit 29 is configured by a light-receiving element such as a phototransistor. The light-projecting unit 28 irradiates light L toward the light-receiving unit 29. When there is no obstruction between the light-projecting unit 28 and the light-receiving unit 29, the light L from the light-projecting unit 28 is received by the light-receiving unit 29. When there is an obstruction between the light-projecting unit 28 and the light-receiving unit 29, the light L from the light-projecting unit 28 is blocked by the obstruction. In this case, the light-receiving unit 29 does not receive the light L from the light-projecting unit 28. Therefore, the light-receiving unit 29 of the detection element 18 functions as a receiving unit that receives the light irradiated from the light-projecting unit 28 as a specific signal.

[0051] The anode of the light-projecting unit 28 is connected to a power source Vcc via a pull-up resistor R1. For example, the pull-up resistor R1 is a variable resistor whose resistance value can be changed under the control of the control unit 7. The cathode of the light-projecting unit 28 is connected to the ground. Therefore, a current If flows steadily through the light-projecting unit 28, and the light-projecting unit 28 is in a light-emitting state.

[0052] A collector terminal of the light receiving unit 29 is connected to a power supply Vcc via a pull-up resistor R2. For example, the pull-up resistor R2 is a variable resistor whose resistance value can be changed under the control of the control unit 7. An emitter terminal of the light receiving unit 29 is connected to ground.

[0053] When an obstruction exists between the light-projecting unit 28 and the light-receiving unit 29 of the detection element 18, the phototransistor of the light-receiving unit 29 is turned off. At this time, the voltage of the collector terminal of the light-receiving unit 29 becomes HIGH. In contrast, when an obstruction does not exist between the light-projecting unit 28 and the light-receiving unit 29 of the detection element 18, the phototransistor of the light-receiving unit 29 is turned on. At this time, the output current Ic flows through the phototransistor. As a result, the voltage of the collector terminal of the light-receiving unit 29 becomes LOW. Therefore, the light-receiving unit 29 of the detection element 18 functions as an output unit that outputs an output signal indicating a predetermined output value based on the received specific signal.

[0054] For example, when the detection element 18 is the sheet detection sensor 17a, if the sheet 9 enters between the light projecting unit 28 and the light receiving unit 29, the detection element 18 detects the sheet 9 and outputs an output signal SIG according to the output current Ic. Also, when the detection element 18 is the loop detection sensor 17b, if a blocking object enters between the light projecting unit 28 and the light receiving unit 29 due to the formation of a loop by the sheet 9, the detection element 18 detects the loop formed state and outputs an output signal SIG according to the output current Ic.

[0055] A low-pass filter 39 including a resistor 37 and a capacitor 38 is connected to the output terminal (collector terminal) of the detection element 18. The output terminal of the low-pass filter 39 is connected to the control unit 7. However, whether or not to provide the low-pass filter 39 between the detection element 18 and the control unit 7 is optional.

[0056] The control unit 7 includes a signal processing unit 50, a CPU 51, a storage unit 52, and a communication unit 53. The signal processing unit 50 is configured by an arithmetic circuit such as an ASIC (Application Specific Integrated Circuit). The CPU 51 is a hardware processor that reads and executes a program 54 stored in the storage unit 52. The CPU 51 comprehensively controls the execution of jobs in the image forming apparatus 1. The CPU 51 also determines the deterioration state of the detection element 18. The storage unit 52 is a non-volatile storage device configured by an HDD (hard disk drive) or an SSD (solid state drive). The storage unit 52 stores the program 54 executed by the CPU 51. The storage unit 52 also stores management information 55 that records the state of the detection element 18. The communication unit 53 is an interface for connecting the image forming apparatus 1 to a network and communicating with an external device.

[0057] Image forming apparatus 1 includes an operation panel 58. Operation panel 58 is a user interface that allows the user to operate image forming apparatus 1. Operation panel 58 includes a display unit 59. Display unit 59 is configured, for example, with a color liquid crystal display. For example, display unit 59 displays an operation screen that can be operated by the user. Display unit 59 is also capable of displaying various notification screens for the user.

[0058] The signal processing unit 50 processes the output signal SIG output from the detection element 18. The signal processing unit 50 includes a comparator 56 and a current detection unit 57.

[0059] The comparator 56 compares the output signal SIG output from the detection element 18 with a predetermined threshold and outputs a binary signal of HIGH or LOW. For example, when the voltage level of the output signal SIG is equal to or greater than the predetermined threshold, the comparator 56 outputs a HIGH signal. On the other hand, when the voltage level of the output signal SIG is less than the predetermined threshold, the comparator 56 outputs a LOW signal. In other words, the comparator 56 outputs a logical value indicating whether the output signal SIG output from the detection element 18 is greater or smaller than the threshold.

[0060] The current detection unit 57 detects the output current Ic flowing through the light receiving unit 29 of the detection element 18. The output signal SIG output from the detection element 18 is a voltage signal corresponding to the output current Ic. Therefore, the current detection unit 57 is configured by, for example, an A / D converter. The current detection unit 57 converts the voltage signal corresponding to the output current Ic into a digital signal, and outputs a signal indicating the output current Ic.

[0061] The CPU 51 executes the program 54 to function as a job control unit 61, a determination unit 62, a life extension processing unit 63, and a notification unit 64.

[0062] The job control unit 61 controls the execution of a job in the image forming apparatus 1. For example, when the job control unit 61 receives a print job via the communication unit 53, it drives each of the conveying unit 2, the image forming unit 3, and the fixing unit 4 to control the operation of forming an image on the sheet 9. For example, the job control unit 61 controls the conveying operation of the sheet 9 and the loop forming operation for the sheet 9 based on a signal output from the comparator 56.

[0063] The determination unit 62 determines the deterioration state of the detector element 18 up to the point where replacement is required, according to the state of the output signal SIG output from the detector element 18. In other words, the determination unit 62 determines the deterioration state of the detector element 18 individually in a situation where the detector element 18 has not yet reached the time to be replaced.

[0064] The characteristics of the detector element 18 gradually change due to the influence of electromagnetic noise generated inside the image forming apparatus 1 or electromagnetic noise received from the outside of the image forming apparatus 1. FIG. 3 is a diagram showing an example of the characteristic change of the detector element 18. FIG. 3 shows a change in the level of the output signal SIG output when the detector element 18 is in the ON state. As shown in FIG. 3, when the detector element 18 continues to receive electromagnetic noise, the voltage level of the output signal SIG gradually increases and approaches the threshold value Th determined by the comparator 56. In addition, depending on the individual difference of the detector element 18, the output signal SIG changes in various manners such as the characteristic changes X1, X2, and X3 shown in FIG. 3. For example, when the output signal SIG changes in the manner of the characteristic change X1 shown in FIG. 3, the output signal SIG exceeds the threshold value Th even when the amount of noise is relatively small. In contrast, when the output signal SIG changes in the manner of the characteristic change X3 shown in FIG. 3, the output signal SIG does not exceed the threshold value Th unless the amount of noise is greater than the characteristic change X1. Although FIG. 3 shows an example in which the slopes of the characteristic changes X1, X2, and X3 are equal, the slopes may differ depending on individual differences in the sensing element 18.

[0065] If the output signal SIG in the ON state constantly exceeds the threshold value Th, the comparator 56 constantly outputs a HIGH signal. In this case, it becomes impossible to distinguish between the ON state and the OFF state of the detection element 18 by the signal output from the comparator 56. Therefore, if the output signal SIG in the ON state constantly exceeds the threshold value Th, the detection element 18 enters a failure state.

[0066] On the other hand, the output signal SIG when in the ON state sometimes exceeds the threshold value Th. In this case, the detection element 18 is in a quasi-fault state or a fault state. In this case, whether the job control unit 61 can normally execute a job depends on the frequency with which the output signal SIG exceeds the threshold value Th. For example, when the frequency with which the output signal SIG exceeds the threshold value Th is relatively low, the job control unit 61 can normally execute a job based on the output signal SIG from the detection element 18 in many cases. Therefore, the detection element 18 is in a first quasi-fault state. On the other hand, when the frequency with which the output signal SIG exceeds the threshold value Th increases, the number of cases in which the job control unit 61 can normally execute a job based on the output signal SIG from the detection element 18 decreases. In this case, the detection element 18 is in a second quasi-fault state. However, when the frequency with which the output signal SIG exceeds the threshold value Th becomes extremely high, the number of cases in which the job control unit 61 can normally execute a job based on the output signal SIG from the detection element 18 decreases significantly. In this case, the detection element 18 is in a fault state.

[0067] Furthermore, when the detection element 18 is affected by electromagnetic noise, the output current Ic when in the on state tends to gradually decrease.

[0068] There are two methods by which the determination unit 62 determines the deterioration state of the detection element 18. The first method is a method of determining the deterioration state of the detection element 18 by evaluating how close the output signal SIG of the detection element 18 is to the threshold value Th. The second method is a method of measuring the output current Ic of the detection element 18. In this embodiment, an example will be described in which the determination unit 62 determines the deterioration state of the detection element 18 by the first method.

[0069] Fig. 4 is a diagram showing a signal output from the comparator 56. The signal SIG1 shown in Fig. 4(a) illustrates a signal when the detection element 18 is in a normal state. When the detection element 18 turns on at timing Ta, the signal SIG1 switches from HIGH to LOW. When the detection element 18 is in a normal state, the signal SIG1 output from the comparator 56 continues to output a LOW signal while the detection element 18 is in the on state.

[0070] In contrast, the signal SIG2 shown in FIG. 4(a) illustrates a signal when the detector element 18 is in a quasi-fault state. When the detector element 18 turns on at timing Ta, the signal SIG2 switches from HIGH to LOW. However, since the output signal SIG of the detector element 18 approaches the threshold value Th, after the signal SIG2 switches from HIGH to LOW, the signal SIG2 output from the comparator 56 switches from LOW to HIGH in response to the fluctuation of the output signal SIG. In the example of FIG. 4(a), the signal SIG2 is HIGH during the period from timing Tb to Tc. When the detector element 18 turns on in this manner, the signal SIG2 output from the comparator 56 fluctuates after the detector element 18 turns on.

[0071] After the detection element 18 is turned on, the judgment unit 62 judges the deterioration state of the detection element 18 by repeatedly performing a logical judgment of the signal output from the comparator 56 at a predetermined period. Fig. 4(b) shows an example of the logical judgment. The signals SIG1, SIG2, SIG3, and SIG4 shown in Fig. 4(b) are signals output from the comparator 56, and represent signals in the process in which the deterioration of the detection element 18 progresses.

[0072] The signal SIG1 is a signal output from the comparator 56 when the detection element 18 is in a normal state. When the signal SIG1 switches from HIGH to LOW at timing Ta, the determination unit 62 repeatedly samples the logical value of the signal SIG1 at a predetermined period from a predetermined timing T1. The sampling interval is an interval of about several milliseconds. When the determination unit 62 samples a logical value indicating a predetermined value (LOW) a predetermined number of times in succession, it determines that the logical value of the signal SIG1 is determined to be a predetermined value. In the example of FIG. 4(b), when the determination unit 62 can sample a logical value indicating a predetermined value (LOW) twice in succession, it determines that the logical value of the signal SIG1 is determined to be determined. In the case of the signal SIG1, the timing at which the determination unit 62 determines that the logical value is determined is T2. Since the signal SIG1 is a signal when the detection element 18 is in a normal state, the number of samples until the determination unit 62 determines that the logical value is determined is the minimum "2".

[0073] The signal SIG2 is a signal output from the comparator 56 when the detection element 18 is slightly deteriorated from the normal state. When the signal SIG2 switches from HIGH to LOW, the determination unit 62 repeatedly performs an operation of sampling the logical value of the signal SIG2 at a predetermined period from a predetermined timing T1. Then, the determination unit 62 determines that the logical value of the signal SIG2 is determined when the logical value indicating the predetermined value (LOW) is sampled a predetermined number of times in succession, as described above. In the example of FIG. 4(b), when the determination unit 62 can sample a logical value indicating the predetermined value (LOW) twice in succession, the determination unit 62 determines that the logical value of the signal SIG2 is determined. The logical value of the signal SIG2 is inverted at timing T2. Therefore, the logical value sampled at timing T2 is not the predetermined value (LOW) but a logical mismatch. As a result, in the case of the signal SIG2, the timing at which the determination unit 62 determines that the logical value is determined is T4. Moreover, since the signal SIG2 is a signal in a state in which the detector element 18 is slightly deteriorated, the number of samples taken until the determining unit 62 determines that the logical value is determined is "4".

[0074] The signal SIG3 is a signal output from the comparator 56 when the deterioration of the detection element 18 progresses. When the signal SIG3 switches from HIGH to LOW, the determination unit 62 repeatedly performs an operation of sampling the logical value of the signal SIG3 at a predetermined period from a predetermined timing T1. Then, the determination unit 62 determines that the logical value of the signal SIG2 is determined when the logical value indicating the predetermined value (LOW) is sampled a predetermined number of times in succession, as described above. In the example of FIG. 4(b), when the determination unit 62 can sample a logical value indicating the predetermined value (LOW) twice in succession, the determination unit 62 determines that the logical value of the signal SIG3 is determined. The logical value of the signal SIG3 is inverted at timings T2 and T4. Therefore, the logical values ​​sampled at timings T2 and T4 are not the predetermined value (LOW) but are logically inconsistent. As a result, in the case of the signal SIG3, the timing at which the determination unit 62 determines that the logical value is determined is T6. Furthermore, since the signal SIG3 is a signal in a state in which the deterioration of the detection element 18 has progressed, the number of samples taken until the determining unit 62 determines that the logical value has been determined is "6".

[0075] The signal SIG4 is a signal output from the comparator 56 when the deterioration of the detection element 18 has progressed further. When the signal SIG4 switches from HIGH to LOW, the determination unit 62 repeatedly performs an operation of sampling the logical value of the signal SIG4 at a predetermined period from a predetermined timing T1. Then, the determination unit 62 determines that the logical value of the signal SIG4 has been determined when the logical value indicating the predetermined value (LOW) is sampled a predetermined number of times in succession, as described above. In the example of FIG. 4(b), when the determination unit 62 can sample a logical value indicating the predetermined value (LOW) twice in succession, the determination unit 62 determines that the logical value of the signal SIG4 has been determined. The logical value of the signal SIG4 is inverted during the period from timing T2 to T4. Therefore, the logical values ​​sampled at timings T2, T3, and T4 are not the predetermined value (LOW) but are logically inconsistent. As a result, in the case of the signal SIG4, the timing at which the determination unit 62 determines that the logical value has been determined is T6. Furthermore, since the signal SIG4 is a signal indicating that the detector element 18 is in an advanced state of deterioration, the number of samples taken until the determining unit 62 determines that the logical value has been determined will be "6".

[0076] Fig. 5 is a diagram showing the sampling results of signals SIG1 to SIG4 shown in Fig. 4. As shown in Fig. 5, in the case of signal SIG1, the number of occurrences of logical mismatch is 0, the number of logic inversions is 0, and the probability of occurrence of logical mismatch is 0 / 2. In addition, in the case of signal SIG2, the number of occurrences of logical mismatch is 1, the number of logic inversions is 1, and the probability of occurrence of logical mismatch is 1 / 4. In addition, in the case of signal SIG3, the number of occurrences of logical mismatch is 2, the number of logic inversions is 2, and the probability of occurrence of logical mismatch is 2 / 6. Furthermore, in the case of signal SIG4, the number of occurrences of logical mismatch is 3, the number of logic inversions is 1, and the probability of occurrence of logical mismatch is 3 / 6.

[0077] When determining the deterioration state of the detector element 18, the determination unit 62 employs at least one of the number of logical mismatch occurrences, the number of logical inversions, and the probability of occurrence of logical mismatch as a determination criterion, as shown in Fig. 5. For example, when the number of logical mismatch occurrences is used as the determination criterion, the determination unit 62 determines that the detector element 18 is in a normal state when the number of logical mismatch occurrences is zero. Furthermore, when the number of logical mismatch occurrences is one or more, the determination unit 62 determines that the detector element 18 is in a quasi-fault state. Furthermore, when the number of logical mismatch occurrences is a predetermined number or more, the determination unit 62 determines that the detector element 18 is in a faulty state.

[0078] 6 is a diagram illustrating an example of the contents of the judgment by the judgment unit 62. The judgment unit 62 judges whether the state of the detection element 18 is a normal state or a degraded state. The degraded state includes a first quasi-fault state, a second quasi-fault state, and a fault state. The second quasi-fault state is a state in which the degraded state is more advanced than the first quasi-fault state. The fault state is a state in which the degraded state is further advanced than the second quasi-fault state.

[0079] After judging the state of the detection element 18, the judgment unit 62 further judges whether the detection element 18 can be reused, and whether a corresponding process and notification are necessary, as shown in FIG. 6. If the detection element 18 is in a normal state, reuse of the detection element 18 is permitted. If reuse is permitted, the detection element 18 will be reused as is when the image forming device 1 is transferred to another user. In contrast, if reuse is prohibited, the detection element 18 will be replaced with a new one when the image forming device 1 is transferred to another user. Furthermore, if the detection element 18 is in a normal state, no corresponding process is required for the detection element 18. Furthermore, if the detection element 18 is in a normal state, notification to the user is also unnecessary.

[0080] When the detector element 18 is in the first quasi-fault state, the detector element 18 cannot be reused. Therefore, when the image forming apparatus 1 is transferred to another user, the detector element 18 needs to be replaced with a new one. Furthermore, when the detector element 18 is in the first quasi-fault state, no response process is required for the detector element 18. Furthermore, when the detector element 18 is in the first quasi-fault state, no notification to the user is required.

[0081] When the detector element 18 is in the second quasi-fault state, the detector element 18 cannot be reused. Furthermore, when the detector element 18 is in the second quasi-fault state, the countermeasure for the detector element 18 is life extension processing. The life extension processing is processing for reducing malfunction of the detector element 18. Details of the life extension processing will be described later. Furthermore, when the detector element 18 is in the second quasi-fault state, it is also unnecessary to notify the user.

[0082] If the detector element 18 is in a faulty state, the detector element 18 cannot be reused. Furthermore, if the detector element 18 is in a faulty state, the countermeasure for the detector element 18 is to immediately replace it. That is, if the detector element 18 is in a faulty state, there is a high possibility that the image forming apparatus 1 will not be able to execute jobs normally, and therefore the detector element 18 needs to be replaced immediately. Furthermore, if the detector element 18 is in a faulty state, it is necessary to notify the user. That is, since the detector element 18 needs to be replaced immediately, it is necessary to notify the user that maintenance work will be performed.

[0083] After making the above-mentioned determination, the determination unit 62 records the determination result in the management information 55. The image forming apparatus 1 is equipped with a plurality of detector elements 18. Therefore, in the management information 55, the determination results for each of the plurality of detector elements 18 are recorded individually.

[0084] The life extension processing unit 63 functions in response to the management information 55 being updated by the determination unit 62. The life extension processing unit 63 reads the management information 55 and executes the life extension processing for the detection element 18 that is determined by the determination unit 62 to require the life extension processing. For example, the life extension processing unit 63 increases the current If flowing through the light-projecting unit 28 of the detection element 18. This increases the intensity of the light L irradiated from the light-projecting unit 28. When the intensity of the light L increases, the amount of light received by the light-receiving unit 29 increases. Therefore, when the detection element 18 is turned on, the output current Ic flowing through the light-receiving unit 29 of the detection element 18 can be increased. As a result, the voltage drop amount in the pull-up resistor R2 increases and the voltage level of the output signal SIG decreases, so that the operation of the detection element 18 approaches normal operation, and the life of the detection element 18 can be extended. For example, the life extension processing unit 63 can increase the current If flowing through the light-projecting unit 28 by decreasing the resistance value of the pull-up resistor R1 of the light-projecting unit 28. The current If flowing through the light projecting unit 28 may be increased by a method different from the above.

[0085] The notification unit 64 functions in response to the management information 55 being updated by the determination unit 62. The notification unit 64 reads out the management information 55 and executes notification processing for the detection element 18 that is determined by the determination unit 62 to require notification. For example, the notification unit 64 identifies the detection element 18 to be notified based on the management information 55, and creates a notification screen that clearly indicates the identified detection element 18 and indicates to the user that it is necessary to immediately replace it. The notification unit 64 notifies the user of the detection element 18 that requires immediate replacement by displaying the notification screen on the display unit 59 of the operation panel 58. The notification unit 64 may also notify a maintenance management server installed in a service center or the like via the communication unit 53 that it is necessary to immediately replace the detection element 18.

[0086] Next, the operation of the image forming apparatus 1 will be described. FIGS. 7 and 8 are flowcharts showing an example of a processing procedure performed by the image forming apparatus 1 of this embodiment. This processing procedure is a processing procedure performed by the control unit 7 as the CPU 51 executes the program 54. When the image forming apparatus 1 starts executing a job (step S10), the control unit 7 judges whether the detection element 18 detects a specific state and turns on (step S11). When the detection element 18 turns on (YES in step S11), the control unit 7 starts sampling the signal output from the comparator 56 (step S12). That is, the control unit 7 starts a process of repeatedly sampling the logical value of the signal output from the comparator 56 at a predetermined period. When the sampling starts, the control unit 7 starts an operation of counting the number of logical mismatches in which the logical value indicates a value different from a predetermined value (step S13). The control unit 7 continues the counting operation until it is determined that the logical value of the signal output from the comparator 56 has been determined. For example, when the logical value acquired by sampling indicates a predetermined value multiple times in succession, the control unit 7 determines that the logical value has been determined. When the control unit 7 determines that the logical value has been determined (YES in step S14), it executes a determination process (step S15).

[0087] 8 is a flowchart showing an example of a detailed processing procedure of the determination process (step S15). When the control unit 7 starts the determination process, it acquires the counted number of mismatch occurrences (step S20). After acquiring the number of mismatch occurrences, the control unit 7 judges whether the number of mismatch occurrences is 0 (step S21). If the number of mismatch occurrences is 0 (YES in step S21), the control unit 7 judges that the detection element 18 is in a normal state (step S22).

[0088] If the number of mismatch occurrences is not 0 (NO in step S21), this means that the output signal SIG output from the detector element 18 exceeded the threshold value Th at least once during the sampling of the logical value. In this case, the detector element 18 is in a deteriorated state, and the control unit 7 sets the detector element 18 to be unreusable (step S23).

[0089] Next, the control unit 7 judges whether the number of mismatch occurrences is 10 or more (step S24). If the number of mismatch occurrences is 10 or more (YES in step S24), the control unit 7 judges that the detection element 18 is in a faulty state (step S25). The control unit 7 also judges that the detection element 18 is an element that needs to be replaced immediately (step S26). Furthermore, the control unit 7 judges that it is necessary to notify the user (step S27).

[0090] If the number of mismatches is less than 10 (NO in step S24), the control unit 7 judges whether the number of mismatches is 5 or more (step S28). If the number of mismatches is 5 or more (YES in step S28), the control unit 7 judges that life extension processing of the detection element 18 is necessary (step S29). On the other hand, if the number of mismatches is less than 5 (NO in step S28), the control unit 7 judges that response processing for the detection element 18 is not necessary. This ends the judgment processing (step S15).

[0091] In the determination process shown in Fig. 8, an example has been described in which the deterioration state of the detector element 18 is determined based on the number of mismatch occurrences. However, this is not limited to this. For example, the control unit 7 may determine the deterioration state of the detector element 18 based on the number of logic inversions or the mismatch occurrence probability shown in Fig. 5, instead of the number of mismatch occurrences.

[0092] Returning to the flowchart of FIG. 7, when the judgment process (step S15) is completed, the control unit 7 judges whether or not to perform life extension processing (step S16). If the control unit 7 judges in the judgment process that life extension processing is necessary, it judges to perform life extension processing in step S16. If life extension processing is to be performed (YES in step S16), the control unit 7 executes life extension processing of the detection element 18 (step S17). For example, the control unit 7 executes life extension processing of the detection element 18 by increasing the current If flowing through the light-projecting unit 28. Note that if life extension processing is not to be performed (NO in step S16), the processing of step S17 is skipped.

[0093] The control unit 7 judges whether or not to perform notification processing (step S18). If the control unit 7 judges in the judgment processing that notification is necessary, it judges to perform notification processing in step S18. If notification processing is to be performed (YES in step S18), the control unit 7 executes notification processing for notifying the user that immediate replacement of the detection element 18 is necessary (step S19). For example, the control unit 7 notifies the user that immediate replacement of the detection element 18 is necessary by displaying a notification screen on the display unit 59 of the operation panel 58. Note that if notification processing is not to be executed (NO in step S18), the processing of step S19 is skipped. This ends the processing by the control unit 7.

[0094] Incidentally, the judgment unit 62 may perform a process of sampling the signal output from the comparator 56 and determining that the logical value has been determined multiple times. FIG. 9 is a diagram showing an example of logical judgment when the process of determining that the logical value has been determined is performed multiple times. The signals SIG1, SIG2, SIG3, and SIG4 shown in FIG. 9 are signals output from the comparator 56, and show signals in the process of the deterioration of the detection element 18 progressing. FIG. 9 shows an example of performing a process of sampling the signal output from the comparator 56 and determining that the logical value has been determined twice. In the example of FIG. 9, the second sampling is started after a predetermined time TP has elapsed since the start of the first sampling. That is, the judgment unit 62 repeats a detection process multiple times to detect a logical change until the logical value indicates a predetermined value multiple times in succession. Then, the judgment unit 62 calculates the mismatch occurrence probability that the logical value does not match the predetermined value in the multiple detection processes, and judges the deterioration state of the detection element based on the mismatch occurrence probability. In this way, the determination unit 62 can determine the deterioration state of the detector element 18 with higher accuracy by performing sampling multiple times after detecting that the detector element 18 has transitioned to the on state.

[0095] As described above, the image forming apparatus 1 of the present embodiment includes the detector element 18 having a receiving unit that receives a specific signal and an output unit that outputs a predetermined output value based on the specific signal received by the receiving unit, and the judgment unit 62 that judges the deterioration state of the detector element 18 until it becomes necessary to replace it, depending on the state of the output value output from the output unit of the detector element 18. For example, the image forming apparatus 1 described above includes the detector element 18 that detects a specific state and outputs a predetermined output signal SIG, and the judgment unit 62 that judges the deterioration state of the detector element 18 until it becomes time to replace it, depending on the state of the output signal SIG. That is, the image forming apparatus 1 of the present embodiment judges the deterioration state of the detector element 18, which gradually deteriorates due to electromagnetic noise, by monitoring the signal state of the output signal SIG output from the detector element 18. Therefore, the image forming apparatus 1 is not limited to simply judging whether the detector element 18 is in a normal state or a fault state, but is also capable of appropriately judging whether the detector element 18 is in a quasi-fault state. In particular, the signal state of the output signal SIG output from the detector element 18 differs depending on the resistance of the detector element 18 to electromagnetic noise. Therefore, even if there are individual differences in the tolerance to electromagnetic noise, the image forming apparatus 1 of this embodiment can appropriately determine the deterioration state of the detector element 18 according to the individual tolerance. In other words, the image forming apparatus 1 of this embodiment measures the tolerance of the detector element 18 to electromagnetic noise based on the output signal SIG, and determines the deterioration state of the detector element 18 based on the tolerance.

[0096] In the above, an example has been described in which the control unit 7 performs the process of determining the deterioration state of the detection element 18 when execution of a job is started in the image forming apparatus 1. However, the control unit 7 does not need to perform the process of determining the deterioration state of the detection element 18 every time a job is executed in the image forming apparatus 1. For example, the control unit 7 may be configured to determine the deterioration state of the detection element 18 every time the number of printed sheets in the image forming apparatus 1 reaches a predetermined number. In addition, the control unit 7 may be configured to determine the deterioration state of the detection element 18 every time a predetermined period (for example, one month) has passed.

[0097] Second embodiment Next, a second embodiment of the present invention will be described. In the first embodiment, an example in which the determination unit 62 determines the deterioration state of the detection element 18 by a first method will be described. In contrast, in the second embodiment, an example in which the determination unit 62 determines the deterioration state of the detection element 18 by a second method will be described. That is, the determination unit 62 of the second embodiment measures the output current Ic of the detection element 18 and determines the deterioration state of the detection element 18. Note that the detailed configuration of the image forming apparatus 1 in this embodiment is the same as the configuration described in the first embodiment.

[0098] The determination unit 62 of this embodiment measures the output current Ic flowing through the light receiving unit 29 of the detection element 18. For example, the determination unit 62 measures the output current Ic based on the signal output from the current detection unit 57. As described above, when the detection element 18 deteriorates due to the influence of electromagnetic noise, the output current Ic flowing through the light receiving unit 29 of the detection element 18 tends to gradually decrease. When the output current Ic decreases, the voltage drop amount in the pull-up resistor R2 decreases, and the voltage level of the output signal SIG changes. That is, the output signal SIG is a signal representing the output current Ic. Also, as described above, the current detection unit 57 converts the output signal SIG into a digital signal and outputs it. Therefore, the determination unit 62 can calculate the output current Ic based on the signal output from the current detection unit 57.

[0099] When the determination unit 62 measures the output current Ic, the determination unit 62 determines the degradation state of the detection element 18 based on the output current Ic. For example, the determination unit 62 calculates the amount of decrease in the output current Ic from the initial state, and determines the degradation state of the detection element 18 based on the amount of decrease. Specifically, similar to the first embodiment, the determination unit 62 determines whether the detection element 18 is in a normal state, a first quasi-fault state, a second quasi-fault state, or a fault state.

[0100] 10 and 11 are flow charts showing an example of a processing procedure performed by the image forming apparatus 1 of the second embodiment. This processing procedure is a processing procedure performed by the control unit 7 as the CPU 51 executes the program 54. When the image forming apparatus 1 starts executing a job (step S30), the control unit 7 judges whether the detection element 18 has detected a specific state and turned on (step S31). When the detection element 18 turns on (YES in step S31), the control unit 7 measures the output current Ic flowing through the light receiving unit 29 of the detection element 18 (step S32). Then, the control unit 7 executes a judgment process (step S33).

[0101] 11 is a flowchart showing an example of a detailed processing procedure of the determination process (step S33). When the control unit 7 starts the determination process, it acquires the output current Ic measured in step S33 (step S40). Then, the control unit 7 determines whether the output current Ic is equal to or greater than the current I1 in the initial state (step S41). If the output current Ic is equal to or greater than the current I1 (YES in step S41), the control unit 7 determines that the detection element 18 is in a normal state (step S42).

[0102] On the other hand, if the output current Ic is less than the current I1 (NO in step S41), the control unit 7 sets the detection element 18 to be unreusable (step S43). Next, the control unit 7 determines whether the output current Ic is less than the current I3 indicating a failure level (step S44). If the output current Ic is less than the current I3 (YES in step S44), the control unit 7 determines that the detection element 18 is in a failure state (step S45). Furthermore, the control unit 7 determines that the detection element 18 is an element that requires immediate replacement (step S46). Furthermore, the control unit 7 determines that it is necessary to notify the user (step S47).

[0103] If the output current Ic is equal to or greater than the current I3 (NO in step S44), the control unit 7 judges whether the output current Ic is less than the current I2 indicating a level requiring life extension processing (step S48). The relationship between the currents I1, I2, and I3 is I1>I2>I3. If the output current Ic is less than the current I2 (YES in step S48), the control unit 7 judges that life extension processing of the detection element 18 is required (step S49). On the other hand, if the output current Ic is equal to or greater than the current I2 (NO in step S48), the control unit 7 judges that no corresponding processing is required for the detection element 18. This ends the judgment processing (step S33).

[0104] Returning to the flowchart of FIG. 10, when the judgment process (step S33) is completed, the control unit 7 judges whether or not to perform life extension processing (step S34). If the control unit 7 judges in the judgment process that life extension processing is necessary, it judges to perform life extension processing in step S34. If life extension processing is to be performed (YES in step S34), the control unit 7 executes life extension processing of the detection element 18 (step S35). Details of the life extension processing are the same as in the first embodiment. Note that if life extension processing is not to be performed (NO in step S34), the processing of step S35 is skipped.

[0105] The control unit 7 judges whether or not to perform notification processing (step S36). If the control unit 7 judges in the judgment processing that notification is necessary, it judges to perform notification processing in step S36. If notification processing is to be performed (YES in step S36), the control unit 7 executes notification processing to notify the user that immediate replacement of the detection element 18 is necessary (step S37). The details of the notification processing are the same as in the first embodiment. Note that if notification processing is not to be executed (NO in step S36), the processing of step S37 is skipped. This ends the processing by the control unit 7.

[0106] As described above, the determination unit 62 of this embodiment measures the output current Ic flowing through the light receiving unit 29 of the detection element 18, and determines the deterioration state of the detection element 18 based on the measurement result of the output current Ic. Therefore, when the detection element 18 detects a specific state and turns to the ON state, the determination unit 62 can immediately determine the deterioration state of the detection element 18. In other words, the determination unit 62 of this embodiment has the advantage of being able to output the determination result more quickly than the first embodiment.

[0107] However, the method of measuring the output current Ic by the determination unit 62 is not limited to the method of measuring based on the signal output from the current detection unit 57. For example, the determination unit 62 may indirectly measure the output current Ic flowing through the light receiving unit 29 by changing the current If flowing through the light projecting unit 28 of the detection element 18. The determination unit 62 changes, for example, the resistance value of the pull-up resistor R1 of the light projecting unit 28 in order to change the current If flowing through the light projecting unit 28. When the current If flowing through the light projecting unit 28 changes, the amount of light received by the light receiving unit 29 changes, and the output current Ic changes. While changing the output current Ic, the determination unit 62 repeatedly samples the signal output from the comparator 56 at a predetermined period, as in the first embodiment. Then, the determination unit 62 measures the output current Ic flowing through the light receiving unit 29 based on the logic change until the sampled logical value indicates a predetermined value (LOW) multiple times in succession. That is, the determination unit 62 estimates the output current Ic based on the number of mismatch occurrences in which the logical value during sampling does not match the predetermined value.

[0108] FIG. 12 is a diagram showing an example of estimating the output current Ic based on the number of mismatch occurrences. As shown in FIG. 12, the judgment unit 62 changes the resistance value of the pull-up resistor R1 in the order of Ra, Rb, Rc, and Rd. The relationship between the resistance values ​​Ra, Rb, Rc, and Rd is Ra>Rb>Rc>Rd. When the resistance value is Ra, if the number of mismatch occurrences during sampling is 0, the output current Ic can be estimated to be equal to or greater than the current I1 in the initial state. When the resistance value is Rb, if the number of mismatch occurrences during sampling is 1 to 4, the output current Ic can be estimated to be equal to or greater than the current I2, which is a level at which the life extension process is required, and less than the current I1. When the resistance value is Rc, if the number of mismatch occurrences during sampling is 5 to 9, the output current Ic can be estimated to be equal to or greater than the current I3, which is a failure level, and less than the current I2, which is a level at which the life extension process is required. Furthermore, when the number of mismatches occurring during sampling is 10 or more for the resistance value Rd, it can be estimated that the output current Ic is less than the current I3, which is the failure level.

[0109] The determination unit 62 counts the number of mismatch occurrences while changing the resistance value of the pull-up resistor R1 to each of the resistance values ​​Ra, Rb, Rc, and Rd. The determination unit 62 estimates the output current Ic based on the number of mismatch occurrences at each of the resistance values ​​Ra, Rb, Rc, and Rd. The determination unit 62 then calculates the output current Ic when the resistance value is returned to its original value based on the rate of change in the output current Ic when the resistance value of the pull-up resistor R1 is changed. The determination unit 62 may measure the output current Ic using this method.

[0110] Furthermore, the determination unit 62 may change the output current Ic by changing the resistance value of the pull-up resistor R2 of the light receiving unit 29, instead of changing the current If flowing through the light projecting unit 28 of the detection element 18. The determination unit 62 counts the number of mismatch occurrences while changing the resistance value of the pull-up resistor R2. The determination unit 62 estimates the output current Ic based on the number of mismatch occurrences for each resistance value. Then, the determination unit 62 calculates the output current Ic when the resistance value is restored based on the rate of change in the output current Ic when the resistance value of the pull-up resistor R2 is changed. The determination unit 62 may measure the output current Ic using this method.

[0111] The configuration and operation of this embodiment other than the above are similar to those described in the first embodiment.

[0112] Third embodiment Next, a third embodiment of the present invention will be described. In this embodiment, an example will be described in which the output current Ic is measured when the number of mismatch occurrences is equal to or greater than a predetermined number. Note that the detailed configuration of the image forming apparatus 1 in this embodiment is the same as the configuration described in the first embodiment.

[0113] The determination unit 62 of this embodiment repeatedly samples the signal output from the comparator 56 at a predetermined period, as in the first embodiment. Then, the determination unit 62 determines whether or not the number of mismatches, in which the logical value does not match the predetermined value, occurs a predetermined number of times or more during the period until the sampled logical value indicates a predetermined value (LOW) multiple times in succession. If the number of mismatches occurs a predetermined number of times or more, the determination unit 62 measures the output current Ic of the detection element 18, as in the second embodiment. Then, the determination unit 62 determines the deterioration state of the detection element 18 based on the measured output current Ic.

[0114] FIG. 13 is a flowchart showing an example of a processing procedure performed by the image forming apparatus 1 of the third embodiment. This processing procedure is a processing procedure performed by the control unit 7 as the CPU 51 executes the program 54. When the image forming apparatus 1 starts executing a job (step S50), the control unit 7 judges whether the detection element 18 has detected a specific state and turned on (step S51). When the detection element 18 turns on (YES in step S51), the control unit 7 starts sampling the signal output from the comparator 56 (step S52). When the sampling starts, the control unit 7 starts an operation of counting the number of logical mismatches in which the logical value indicates a value different from a predetermined value (step S53). The control unit 7 continues the counting operation until it is determined that the logical value of the signal output from the comparator 56 has been determined. When the control unit 7 determines that the logical value has been determined (YES in step S54), it acquires the number of mismatch occurrences (step S55). Then, the control unit 7 judges whether the number of mismatch occurrences is equal to or greater than a predetermined number (step S56). For example, the predetermined number is one. If the number of mismatch occurrences is less than the predetermined number of times (NO in step S56), the process by the control unit 7 ends.

[0115] If the number of mismatch occurrences is equal to or greater than the predetermined number (YES in step S56), the control unit 7 measures the output current Ic flowing through the light receiving unit 29 of the detection element 18 (step S57). Then, the control unit 7 executes a determination process (step S58). A detailed flowchart of this determination process (step S58) is the same as the flowchart shown in FIG.

[0116] When the judgment process (step S58) is completed, the control unit 7 judges whether or not to perform life extension processing (step S59). If the control unit 7 judges in the judgment process that life extension processing is necessary, it judges to perform life extension processing in step S59. If life extension processing is to be performed (YES in step S59), the control unit 7 executes life extension processing of the detection element 18 (step S60). The details of the life extension processing are the same as those in the first embodiment. Note that if life extension processing is not to be performed (NO in step S59), the processing of step S60 is skipped.

[0117] The control unit 7 judges whether or not to perform notification processing (step S61). If the control unit 7 judges in the judgment processing that notification is necessary, it judges to perform notification processing in step S61. If notification processing is to be performed (YES in step S61), the control unit 7 executes notification processing to notify the user that the detection element 18 needs to be immediately replaced (step S62). The details of the notification processing are the same as in the first embodiment. Note that if notification processing is not to be executed (NO in step S61), the processing of step S62 is skipped. This ends the processing by the control unit 7.

[0118] As described above, the determination unit 62 of this embodiment repeatedly samples the logical value based on the output signal SIG output from the light receiving unit 29 of the detection element 18 at a predetermined period. Then, the determination unit 62 measures the output current Ic flowing through the light receiving unit 29 when the number of mismatches, in which the logical value does not match the predetermined value, is equal to or greater than a predetermined number of times during the period until the logical value indicates the predetermined value multiple times in succession. The determination unit 62 determines the deterioration state of the detection element 18 based on the measurement result of the output current Ic. This allows the determination unit 62 to appropriately determine whether the detection element 18 is in a first quasi-fault state, a second quasi-fault state, or a fault state, as in the first and second embodiments.

[0119] Contrary to the above, the determination unit 62 may first measure the output current Ic flowing through the light-receiving unit 29. In this case, when the determination unit 62 determines that the detection element 18 has deteriorated based on the measurement result of the output current Ic, the determination unit 62 may repeatedly sample the logical value based on the output signal SIG output from the light-receiving unit 29 of the detection element 18 at a predetermined period. In this case, the determination unit 62 determines whether the detection element 18 is in a first quasi-fault state, a second quasi-fault state, or a fault state based on the number of mismatch occurrences in which the logical value does not match a predetermined value during a period until the logical value indicates a predetermined value multiple times in succession.

[0120] The configuration and operation of this embodiment other than the above are similar to those described in the first or second embodiment.

[0121] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described. In this embodiment, an example in which the control unit 7 appropriately controls the timing at which the process for determining the deterioration state of the detection element 18 is performed will be described.

[0122] FIG. 14 is a diagram showing an example of a configuration in which a plurality of image forming apparatuses 1a, 1b, and 1c can communicate with a server apparatus 100. The server apparatus 100 communicates with each of the plurality of image forming apparatuses 1a, 1b, and 1c via a network such as the Internet. For example, when a trouble such as a jam occurs during execution of a job, the image forming apparatuses 1a and 1b transmit trouble information D1 to the server apparatus 100. The server apparatus 100 collects the trouble information D1 and analyzes the cause of the trouble occurring in the image forming apparatuses 1a and 1b. As a result, when it is determined that the cause of the trouble is deterioration of the detection element 18, the server apparatus 100 transmits a judgment command D2 to the image forming apparatus 1c equipped with the same detection element 18 as the image forming apparatuses 1a and 1b in which the trouble occurred. When the image forming apparatus 1c receives the judgment command D2 transmitted from the server apparatus 100, it starts a process of judging the deterioration state of the detection element 18.

[0123] FIG. 15 is a block diagram showing an example of a configuration for determining the deterioration state of the detection element 18 in the fourth embodiment. The CPU 51 of the control unit 7 executes the program 54 to function as a determination unit 65. The determination unit 65 determines whether or not to determine the deterioration state of the detection element 18 based on information received from the server device 100, which is an external device. For example, when the determination unit 65 receives a determination command D2 from the server device 100, it determines to determine the deterioration state of the detection element 18. In this case, the control unit 7 executes a process for determining the deterioration state of the detection element 18 when executing a job after receiving the determination command D2 from the server device 100. At this time, the control unit 7 may execute the processes described in each of the first to third embodiments.

[0124] In this way, when a problem occurs in the other image forming apparatuses 1a and 1b due to deterioration of the detector element 18, the image forming apparatus 1c having the same detector element 18 mounted thereon determines the deterioration state of the detector element 18. Therefore, the image forming apparatus 1c can appropriately detect the deterioration state of the detector element 18 before a problem occurs due to deterioration of the detector element 18.

[0125] In the above, an example has been described in which the server device 100 transmits the judgment command D2 to the image forming device 1c, and the image forming device 1c judges the deterioration state of the detection element 18 upon receiving the judgment command D2. However, the present invention is not limited to this, and the server device 100 does not need to transmit the judgment command D2 to the image forming device 1c. For example, the image forming device 1c may periodically access the server device 100 and inquire about the occurrence of troubles in the other image forming devices 1a and 1b. In this case, the image forming device 1c can determine whether or not it is necessary to judge the deterioration state of the detection element 18 based on the response from the server device 100. Therefore, the image forming device 1c may judge the deterioration state of the detection element 18 based on the result of the determination.

[0126] Fifth embodiment Next, a fifth embodiment of the present invention will be described below, which is another example in which the control unit 7 appropriately controls the timing at which the control unit 7 performs the process of determining the deterioration state of the detection element 18.

[0127] FIG. 16 is a block diagram showing an example of a configuration for determining the deterioration state of the detector element 18 in the fifth embodiment. The image forming apparatus 1 includes a noise detection unit 66 provided near the detector element 18. The noise detection unit 66 is configured by an antenna for detecting electromagnetic noise near the detector element 18. The CPU 51 of the control unit 7 executes the program 54 to function as a determination unit 65. The determination unit 65 detects electromagnetic noise near the detector element 18 based on the detection result of the noise detection unit 66 and determines whether to determine the deterioration state of the detector element 18. For example, when the noise amount of the electromagnetic noise is greater than a predetermined amount, the determination unit 65 determines to determine the deterioration state of the detector element 18. In this case, the control unit 7 executes a process for determining the deterioration state of the detector element 18 when executing a job after the determination by the determination unit 65 is made. At this time, the control unit 7 may execute the process described in each of the first to third embodiments.

[0128] Therefore, the image forming apparatus 1 of the present embodiment can appropriately determine the deterioration state of the detector element 18 when there is a possibility that the deterioration of the detector element 18 is progressing due to the influence of electromagnetic noise.

[0129] Sixth embodiment Next, a sixth embodiment of the present invention will be described. In this embodiment, an example will be described in which the timing to prompt the user to replace the sensing element 18 is controlled when the deterioration state of the sensing element 18 is the first quasi-fault state or the second quasi-fault state.

[0130] 17 is a block diagram showing an example of a configuration for determining a deterioration state of the detection element 18 in the sixth embodiment. The image forming apparatus 1 stores history information 68 including a job execution history in the storage unit 52. That is, when a job is executed in the image forming apparatus 1, the job control unit 61 generates history information 68 including the job execution history and stores it in the storage unit 52.

[0131] The notification unit 64 reads the management information 55 and determines whether the detection element 18 is in the first quasi-fault state or the second quasi-fault state. When the detection element 18 is in the first quasi-fault state or the second quasi-fault state, the deterioration of the detection element 18 progresses. Therefore, when the detection element 18 is in the first quasi-fault state or the second quasi-fault state, the notification unit 64 reads the history information 68 and determines the timing to prompt the user to replace the detection element 18. Specifically, the notification unit 64 identifies the frequency of use by the user based on the history information 68. In addition, the notification unit 64 estimates the remaining period until the detection element 18 becomes in a fault state based on the frequency of use by the user and the state of the detection element 18 (the first quasi-fault state or the second quasi-fault state). Then, when the remaining period becomes shorter than a predetermined period, the notification unit 64 notifies the user to prompt the user to replace the detection element 18. This allows the user to perform the work to replace the detection element 18 before the detection element 18 becomes in a fault state. The notification urging the user to replace the detection element 18 may be sent to the server device 100 instead of to the user alone.

[0132] (Modification) Although a number of preferred embodiments of the present invention have been described above, the present invention is not limited to the contents described in each of the embodiments, and various modifications are possible.

[0133] In the above embodiment, an example has been described in which the detection element 18 is a transmission type photosensor. However, the detection element 18 is not limited to a transmission type photosensor. For example, the detection element 18 may be a reflection type photosensor. Furthermore, the detection element 18 may be configured as a sensor other than a photosensor.

[0134] Furthermore, the program 54 described in the above embodiment is not limited to being stored in advance in the storage unit 52 of the image forming apparatus 1. For example, the program 54 may be a transaction target by itself. In this case, the program 54 may be provided in a downloadable form via a network such as the Internet, or may be provided in a state recorded on a computer-readable recording medium such as a CD-ROM. [Explanation of symbols]

[0135] 1,1a,1b,1c Image forming device 7 Control section 18 Detector element 28 Light projector 29 Light receiving section 50 Signal processing section 51 CPU 52 Storage section 53 Communications Department 54 Programs 56 Comparator 57 Current detection section 61 Job control section 62 Judgment Department 63 Life Support Department 64 Notification Department 65 Decision Section

Claims

1. A sensing element including a receiving unit that receives a specific signal and an output unit that outputs a predetermined output value based on the specific signal received by the receiving unit; a determination unit that determines a deterioration state of the detection element to a state where replacement is required according to an output state from the output unit; An image forming apparatus comprising:

2. The detector element outputs an output signal that has a predetermined output value when a specific state is detected, 2 . The image forming apparatus according to claim 1 , wherein the determining unit determines a deterioration state of the detector element until the detector element reaches a time to be replaced, depending on a state of an output value output as the output signal.

3. 2. The image forming apparatus according to claim 1, wherein the determining section measures a resistance of the detector element against electromagnetic noise based on the output value, and determines a deterioration state of the detector element based on the resistance.

4. 3. The image forming apparatus according to claim 2, wherein the determining section determines the deterioration state of the detector element based on a state from when the detector element detects the specific state until when the output value is determined.

5. 2. The image forming apparatus according to claim 1, wherein the determination unit determines the deterioration state of the detector element by distinguishing between a quasi-failure state and a failure state of the detector element.

6. The detection element has a light projecting portion and a light receiving portion, 3. The image forming apparatus according to claim 2, wherein the light receiving section outputs the output signal in accordance with an amount of light received when the light emitted from the light projecting section is received.

7. The image forming apparatus according to claim 6, characterized in that the judgment unit repeatedly samples a logical value based on the output signal output from the light receiving unit at a predetermined period, and judges the deterioration state of the detection element based on a logical change until the logical value indicates a predetermined value multiple times in succession.

8. The image forming apparatus according to claim 7, characterized in that the judgment unit counts the number of times that the logical value does not match the specified value during a period until the logical value indicates the specified value multiple times in succession, and judges the deterioration state of the detection element based on the number of times that the mismatch occurs.

9. The image forming apparatus according to claim 7 , wherein the determination unit counts the number of times the logical value is inverted during a period until the logical value indicates a predetermined value multiple times in succession, and determines the deterioration state of the detection element based on the number of times of inversion.

10. The image forming apparatus according to claim 7, characterized in that the judgment unit calculates a mismatch probability in which the logical value does not match the specified value during a period until the logical value indicates the specified value multiple times in succession, and judges the deterioration state of the detection element based on the mismatch probability.

11. The image forming apparatus according to claim 7, characterized in that the judgment unit repeats a detection process multiple times to detect a logical change until the logical value indicates a predetermined value multiple times in succession, calculates a mismatch probability in which the logical value does not match the predetermined value in multiple detection processes, and judges the deterioration state of the detection element based on the mismatch probability.

12. 7. The image forming apparatus according to claim 6, wherein the determining section measures an output current flowing through the light receiving section, and determines a deterioration state of the detection element based on a measurement result of the output current.

13. The image forming apparatus according to claim 12, characterized in that the judgment unit changes the current flowing through the light-projecting unit, repeatedly samples a logical value based on the output signal output from the light-receiving unit at a predetermined period, and measures the output current flowing through the light-receiving unit based on the logical change until the logical value indicates a predetermined value multiple times in succession.

14. The image forming apparatus according to claim 12, wherein the determination unit changes a pull-up resistor connected to the light receiving unit, repeatedly samples a logical value based on the output signal output from the light receiving unit at a predetermined period, and measures an output current flowing to the light receiving unit based on a logical change until the logical value indicates a predetermined value multiple times in succession.

15. The image forming apparatus according to claim 7, wherein the judgment unit repeatedly samples a logical value based on the output signal output from the light receiving unit at a predetermined period, and if the number of times that the logical value does not match the predetermined value during a period until the logical value indicates the predetermined value multiple times in succession is equal to or greater than a predetermined number, measures an output current flowing through the light receiving unit, and judges the deterioration state of the detection element based on the measurement result of the output current.

16. A communication unit that communicates with an external device; A determination unit that determines whether to determine a deterioration state of the detection element based on information received from the external device; Further comprising: The image forming apparatus according to claim 1, characterized in that, when the decision unit decides to determine the deterioration state of the detection element, the judgment unit determines the deterioration state of the detection element until it reaches the time for replacement based on the output status from the output unit.

17. A determination unit that detects electromagnetic noise and determines whether or not to determine a deterioration state of the detection element; Further comprising: The image forming apparatus according to claim 1, characterized in that, when the decision unit decides to determine the deterioration state of the detection element, the judgment unit determines the deterioration state of the detection element until it reaches the time for replacement based on the output status from the output unit.

18. A life extension processing unit that performs a life extension process on the detection element; Equipped with The determination unit determines whether or not a life extension process for the detection element is possible based on a deterioration state of the detection element, The image forming apparatus according to claim 6 , wherein the life extension processing unit performs the life extension processing of the detector element when the determination unit determines that the life extension processing of the detector element is possible.

19. 20. The image forming apparatus according to claim 18, wherein the life extension processing unit performs the life extension process for the detection element by increasing a current flowing in the light projecting unit.

20. 20. The image forming apparatus according to claim 18, wherein the life extension processing unit performs the life extension process for the detection element by increasing a pull-up resistance connected to the light receiving unit.

21. 1. A deterioration state determination method for determining a deterioration state of a detector element in an image forming apparatus including a detector element that outputs an output signal, comprising: A deterioration state determining method, comprising: determining a deterioration state of said detection element until the detection element reaches a time to be replaced according to a state of said output signal.

22. A program executed in an image forming apparatus having a detection element that outputs an output signal, the program including: determining a deterioration state of the detection element until the detection element needs to be replaced according to a state of the output signal; A program characterized by executing the above.

Images