Image forming apparatus, feeder and information processing device

Abstract

To specify defective components among components related to sheet conveyance.SOLUTION: A supply motor 108 drives a pickup roller 105, a supply roller 106 and a separation roller 107. A supply sensor 111 is disposed at the downstream side of the rollers 106, 107 to detect a top level sheet 2 sent by the supply roller 106. A torque detection part 108s detects torque of the supply motor 108. A control part 400 calculates a maximum amplitude value of ripple components of an output signal of the torque detection part 108s and calculates duration of detection of the top level sheet 2 by the supply sensor 111 each time the top level sheet 2 is sent out. The control part 400 determines that the qualities of the rollers 106, 107 to be satisfactory by comparing the maximum amplitude value and the duration with a prescribed first threshold and second threshold, respectively.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, a feeder, and an information processing apparatus. [Background technology]

[0002] Patent Document 1 discloses a technique for detecting an abnormality in a first roller pair, a second roller pair, and a third roller pair, which are arranged in order in the transport direction of a medium. The second roller pair is driven by a motor, and a torque detection unit detects the load torque of the motor. During a period in which the medium is transported by the first roller pair and the second roller pair, a CPU acquires the load torque detected by the torque detection unit. During a period in which the medium is transported by the second roller pair and the third roller pair, the CPU acquires the load torque detected by the torque detection unit. The CPU compares these load torques with a reference value. The CPU determines the presence or absence of an abnormality in the first roller pair, the second roller pair, and the third roller pair through such a comparison. However, the technique of Patent Document 1 cannot determine which roller of the first roller pair is abnormal. The same applies to the second roller pair and the third roller pair. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-26673 A Summary of the Invention [Problem to be solved by the invention]

[0004] An objective of one or more embodiments of the present invention is to identify faulty components involved in transporting sheets, such as media and paper. [Means for solving the problem]

[0005] In order to solve the above problems, according to one aspect of the present invention, an image forming apparatus includes a conveying unit, a supply motor, a detection unit, a torque detection unit, and a control unit. The conveying unit feeds the topmost sheet of a plurality of stacked sheets. The supply motor drives the conveying unit. The detection unit detects the topmost sheet. The torque detection unit detects the torque of the supply motor. The control unit identifies defective parts from among parts related to the conveyance of the sheets based on the detection results of the detection unit and the detection results of the torque detection unit.

[0006] According to one aspect of the present invention, an image forming apparatus includes a pickup roller, a supply roller, a separation roller, a supply motor, a detection unit, a torque detection unit, and a control unit. The pickup roller feeds the topmost sheet of a stack of sheets one by one. The supply roller is disposed downstream of the pickup roller and feeds the topmost sheet fed by the pickup roller. The separation roller is disposed downstream of the pickup roller and separates the topmost sheet fed by the supply roller from the sheet below it. The supply motor drives the pickup roller, the supply roller, and the separation roller. The detection unit is disposed downstream of the supply roller and the separation roller and detects the topmost sheet fed by the supply roller. The torque detection unit detects the torque of the supply motor and outputs an output signal representing the torque of the supply motor. The control unit calculates a maximum amplitude value of a ripple component of the output signal of the torque detection unit every time the detection unit detects the topmost sheet, and calculates a duration of detection of the topmost sheet by the detection unit. The control unit transmits the maximum amplitude value and the duration in association with each other to an information processing device.

[0007] According to one aspect of the present invention, an image forming apparatus includes a pickup roller, a supply roller, a separation roller, a supply motor, a detection unit, a torque detection unit, and a control unit. The pickup roller feeds the topmost sheet of a stack of sheets one by one. The supply roller is disposed downstream of the pickup roller and feeds the topmost sheet fed by the pickup roller. The separation roller is disposed downstream of the pickup roller and separates the topmost sheet fed by the supply roller from the sheet below it. The supply motor drives the pickup roller, the supply roller, and the separation roller. The detection unit is disposed downstream of the supply roller and the separation roller and detects the topmost sheet fed by the supply roller. The torque detection unit detects the torque of the supply motor and outputs an output signal representing the torque. The control unit executes a calculation process to calculate a maximum amplitude value of a ripple component of the output signal of the torque detection unit and to calculate a duration of detection of the topmost sheet by the detection unit every time the detection unit detects the topmost sheet. The control unit executes a comparison process in which the maximum amplitude value and the duration are compared with a predetermined first threshold value and a predetermined second threshold value, respectively. The control unit executes a determination process in which, if the maximum amplitude value is equal to or greater than the first threshold value and the duration is equal to or greater than the second threshold value, the control unit determines that the supply roller is defective if the maximum amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, the control unit determines that the separation roller is defective if the maximum amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, and determines that the supply roller and the separation roller are good if the maximum amplitude value is less than the first threshold value.

[0008] According to one aspect of the present invention, an image forming apparatus includes a placement table, a pickup roller, a detection unit, a supply motor, a torque detection unit, a lifter, and a control unit. A plurality of stacked sheets are placed on the placement table. The pickup roller delivers the topmost sheet of the plurality of sheets one by one. The detection unit is disposed at the same height as the position where the pickup roller is provided, and detects the topmost sheet. The supply motor drives the pickup roller. The torque detection unit detects the torque of the supply motor and outputs an output signal representing the torque. The lifter lifts the placement table toward the pickup roller when the detection unit does not detect the topmost sheet, and stops lifting the placement table when the detection unit detects the topmost sheet. The control unit calculates an average value of the ripple components of the output signal of the torque detection unit every time the topmost sheet is delivered by the pickup roller. The control unit transmits the average value to an information processing device in association with a detection result of the detection unit at the time of calculating the average value.

[0009] According to one aspect of the present invention, an image forming apparatus includes a placement table, a pickup roller, a detection unit, a supply motor, a torque detection unit, a lifter, and a control unit. A plurality of stacked sheets are placed on the placement table. The pickup roller delivers the topmost sheet of the plurality of sheets one by one. The detection unit is disposed at the same height as the pickup roller and detects the topmost sheet. The supply motor drives the pickup roller. The torque detection unit detects the torque of the supply motor and outputs an output signal representing the torque. The lifter lifts the placement table toward the pickup roller when the detection unit does not detect the topmost sheet, and stops lifting the placement table when the detection unit detects the topmost sheet. The control unit executes a calculation process to calculate an average value of the ripple component of the output signal of the torque detection unit every time the topmost sheet is delivered by the pickup roller. The control unit executes a comparison process to compare the average value with a predetermined threshold value. The control unit executes a judgment process to judge the detection unit to be good if, as a result of the comparison process, the average value is equal to or greater than the threshold value or the detection result of the detection unit is non-detection of the topmost sheet, and to judge the detection unit to be defective if the average value is less than the threshold value and the detection result is detection of the topmost sheet. Effect of the Invention

[0010] According to one aspect of the present invention, it is possible to identify a defective part from among parts related to sheet transport. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a front view showing the inside of an image forming apparatus. [Diagram 2] FIG. 2 is a block diagram of the image forming apparatus. [Diagram 3] FIG. 3 is a timing chart showing the torque of the supply motor expressed as a current level. [Figure 4]FIG. 4 is a timing chart showing the torque of the supply motor expressed as a current level. [Diagram 5] FIG. 5 is a timing chart showing the torque of the supply motor expressed as a current level. [Figure 6] FIG. 6 is a graph showing changes in the maximum ripple amplitude and the first duration with an increase in the number of printed sheets. [Figure 7] FIG. 7 is a graph showing changes in the maximum ripple amplitude and the first duration with an increase in the number of printed sheets. [Figure 8] FIG. 8 is a graph showing the change in the output signal from the upper limit sensor and the average torque value with an increase in the number of printed sheets. [Figure 9] FIG. 9 is a graph showing the change in the output signal from the upper limit sensor and the average torque value with an increase in the number of printed sheets. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described with reference to the drawings. The features and technical effects of the embodiments will be understood from the following detailed description and drawings. However, the scope of the present invention is not limited to the embodiments disclosed below. The drawings are provided for illustrative purposes only, and therefore the scope of the present invention is not limited to the illustrations in the drawings.

[0013] <1. Image forming device> Fig. 1 is a front view showing a schematic diagram of an image forming apparatus 1. In Fig. 1, the housing 10 is cut along a vertical cross section parallel to the up-down and left-right directions so that components provided inside the housing 10 of the image forming apparatus 1 can be seen. Fig. 2 is a block diagram of the image forming apparatus 1.

[0014] The image forming apparatus 1 is a multi-function peripheral (MFP) that has an image input function, a copying function, and a printing function.

[0015] The image forming apparatus 1 includes an image input device 500 with an automatic document feed function. The image input device 500 is mounted on the housing 10 of the image forming apparatus 1. The image input device 500 includes an automatic document feeder and an image scanner. The image input device 500 feeds document sheets one by one to the image scanner using the automatic document feeder, and reads images of the front side or back side, or both, of the document sheets one by one using the image scanner.

[0016] The image forming apparatus 1 includes a control unit 400 and a display unit 410 . The display unit 410 is, for example, a liquid crystal display device or an organic EL display device with a touch panel. The display unit 410 is attached to the upper part of the front surface of the housing 10, facing diagonally upward and forward. The display unit 410 displays an image according to a video signal transferred from the control unit 400. The display unit 410 also serves as the display unit of the feeder 100 described below.

[0017] The control unit 400 is provided inside the housing 10. The control unit 400 has a CPU (Central Processing Unit), a RAM (Random Access Memory), a storage unit, a communication device, and the like. The storage unit is, for example, a semiconductor memory or a magnetic storage device. The control unit 400 controls the entire image forming apparatus 1. The communication device is a network card, a WiFi (registered trademark) slave, or a mobile phone line communication module. The control unit 400 is connected to the Internet via the communication device and, if necessary, a LAN (Local Area Network), or the like. The control unit 400 can communicate with an external server 450 via the Internet. A secure communication protocol such as a VPN (Virtual Private Network) may be adopted for communication between the control unit 400 and the external server 450. The control unit 400 also serves as a control unit for the feeder 100 described below.

[0018] The external server 450 is an information processing device configured by a computer system. The external server 450 may be configured by one computer system, or may be configured by multiple computer systems capable of distributed processing or parallel processing. The external server 450 may be a cloud computing system.

[0019] The image forming apparatus 1 includes a printer 200. The printer 200 is provided inside a housing 10. The printer 200 includes a feeder 100, a printer main body 210, and a discharge unit 300.

[0020] As shown in Fig. 1, a plurality of sheet stacks 3 are stored in a feeder 100. Each sheet stack 3 has a plurality of stacked sheets 2. The sheets 2 are paper. The sheets 2 are also called recording media or media.

[0021] The feeder 100 is provided at the bottom inside the housing 10. The feeder 100 feeds the stacked sheets 2 one by one from the top to the bottom to a timing roller 250 of the printer main body 210.

[0022] The feeder 100 has a lower cassette 101, a loading table 102, a lifter 103, a pickup roller 105, a supply roller 106, a separation roller 107, a supply motor 108, a torque detection unit 108s, an upper limit sensor 110, a supply sensor 111, a transport sensor 112, a pair of transport rollers 120, a transport motor 121, an upper cassette 131, a loading table 132, a lifter 133, a pickup roller 135, a supply roller 136, a separation roller 137, a supply motor 138, an upper limit sensor 140, a supply sensor 141 and a transport sensor 142. The components having the lower cassette 101, the loading platform 102, the lifter 103, the pickup roller 105, the supply roller 106 and the separation roller 107 constitute the lower conveying section, and the components having the upper cassette 131, the loading platform 132, the lifter 133, the pickup roller 135, the supply roller 136 and the separation roller 137 constitute the upper conveying section.

[0023] The lower cassette 101 is shaped like a box with an open top. The lower cassette 101 is accommodated in the housing 10 through a slot formed in the lower part of the front surface of the housing 10. The lower cassette 101 is guided in the front-rear direction by a slide rail provided in the lower part inside the housing 10. The lower cassette 101 can be removed from the slot to the front of the housing 10.

[0024] The mounting table 102 is provided so as to be able to rise and fall within the lower cassette 101. More specifically, the mounting table 102 is disposed within the lower cassette 101, the left end of the mounting table 102 is rotatably connected to the lower cassette 101, and the right end of the mounting table 102 is lifted and lowered with the left end of the mounting table 102 as a fulcrum. A plurality of sheets 2 are stacked on the mounting table 102.

[0025] The lifter 103 is provided in the housing 10 at the far right of the slot. When the lower cassette 101 and the mounting table 102 are inserted into the slot, the lifter 103 is disposed below the right part of the mounting table 102 in the lower cassette 101. The lifter 103 has a motor 104 that operates the lifter 103. The lifter 103 lifts the mounting table 102 by the power of the motor 104, and presses the topmost sheet 2 against a pickup roller 105 with an appropriate pressure.

[0026] The pickup roller 105 is rotatably supported by the housing 10 at the rear right of the slot. When the lower cassette 101 and the mounting table 102 are inserted into the slot and the lifter 103 lifts the mounting table 102, the topmost sheet 2 of the stacked sheets 2 is pressed against the pickup roller 105.

[0027] The supply roller 106 is rotatably supported by the housing 10 at the rear right side of the slot. The supply roller 106 is disposed away from the pickup roller 105 in the feeding direction of the sheet 2. The feeding direction of the sheet 2 is the rightward direction.

[0028] The separation roller 107 is rotatably supported by the housing 10 at the rear right of the slot. The separation roller 107 is pressed toward the supply roller 106 from below by the elastic force of a spring.

[0029] The pickup roller 105 and the supply roller 106 are connected to a supply motor 108 via a belt transmission mechanism or the like. The supply motor 108 periodically drives the pickup roller 105, the supply roller 106, and the separation roller 107. Then, the pickup roller 105 sends out the stacked sheets 2 one by one from the top to the supply roller 106 and the separation roller 107, and the supply roller 106 sends the sheets 2 to the conveying roller 120. Even if multiple sheets 2 are sent by the pickup roller 105, the separation roller 107 returns the sheet 2 below the top sheet 2 to separate the top sheet 2 from the sheet 2 below it, so that the separation roller 107 prevents multiple sheets 2 from being sent.

[0030] As shown in FIG. 2, the torque of the supply motor 108 is detected by a torque detection unit 108s, and a signal representing the detected torque is output from the torque detection unit 108s to the control unit 400. The torque detection unit 108s includes a motor driver 108a, a resistor 108b, an amplifier 108c, and a low-pass filter 108d. The motor driver 108a is connected between the supply motor 108 and a constant-voltage power supply 108e. The motor driver 108a receives power from the constant-voltage power supply 108e. The control unit 400 controls the motor driver 108a, so that the motor driver 108a supplies power from the constant-voltage power supply 108e to the supply motor 108 to drive the supply motor 108. The magnitude of the current supplied from the constant-voltage power supply 108e to the supply motor 108 via the motor driver 108a is converted into a voltage signal by the resistor 108b. The voltage signal of the resistor 108b represents the torque of the supply motor 108. The amplifier 108c receives and amplifies the voltage signal of the resistor 108b. The amplifier 108c outputs the amplified voltage signal to the low-pass filter 108d. The low-pass filter 108d removes high-frequency components exceeding a predetermined cutoff frequency from the amplified voltage signal and passes low-frequency components equal to or lower than the cutoff frequency. The high-frequency components removed by the low-pass filter 108d are torque ripples caused by electrical influences of the supply motor 108 and the motor driver 108a. The low-frequency components passed by the low-pass filter 108d are torque ripples caused by mechanical influences of the transmission mechanism from the supply motor 108 to the rollers 105 to 107. The signal that has passed through the low-pass filter 108d is input to the control unit 400.

[0031] Fig. 3 is a timing chart showing a change in current of resistor 108b when control unit 400 controls supply motor 108 via motor driver 108a. In Fig. 3, the horizontal axis represents time, and the vertical axis represents the magnitude of current. The range of the horizontal axis in Fig. 3 is the period during which one sheet 2 is transported by pickup roller 105, supply roller 106, and separation roller 107.

[0032] When the supply motor 108 is driven to transport the sheet 2 by the pickup roller 105 and the supply roller 106, torque is generated in the supply motor 108. Therefore, the current of the resistor 108b is large, and the level of the signal input from the low-pass filter 108d to the control unit 400 is high. The signal contains a torque ripple component caused by the mechanical influence from the supply motor 108 to the rollers 105 to 107.

[0033] When the pickup roller 105, the supply roller 106, and the separation roller 107 are normal, the waveform of the current of the resistor 108b is as shown in FIG. 3. On the other hand, when the supply roller 106 is deteriorated due to dust such as paper powder adhering to the supply roller 106, the waveform of the current of the resistor 108b is as shown in FIG. 4. The deterioration of the supply roller 106 causes the supply roller 106 to slip relative to the sheet 2. The slip of the supply roller 106 generates abnormal noise in the transmission mechanism from the supply motor 108 to the rollers 105 to 107. Since such abnormal noise appears in the waveform of the current of the resistor 108b, as shown in FIG. 4, the slip of the supply roller 106 increases the torque ripple component and increases the amplitude of the waveform of the current of the resistor 108b. The same applies when the separation roller 107 is deteriorated.

[0034] If the deterioration of the supply roller 106 progresses further due to a large amount of dust adhering to the supply roller 106, the waveform of the current of the resistor 108b will become as shown in Figure 5. As shown in Figure 5, the torque ripple component increases further.

[0035] 1, the transport roller 120 is rotatably supported by the housing 10 above the supply roller 106 and the separation roller 107. The transport roller 120 is connected to a transport motor 121 via a belt transmission mechanism or the like. The transport motor 121 drives the transport roller 120, whereby the transport roller 120 sends the sheet 2 to the timing roller 250.

[0036] The upper limit sensor 110 is provided at the same height as the position where the pickup roller 105 is provided. The upper limit sensor 110 is a detection unit that detects the uppermost sheet 2 pressed against the pickup roller 105. The upper limit sensor 110 outputs an output signal indicating whether the sheet 2 is detected to the control unit 400. Specifically, when the uppermost sheet 2 is pressed against the pickup roller 105 with an appropriate pressure, the upper limit sensor 110 detects the uppermost sheet 2, and the output signal of the upper limit sensor 110 is at a high level. On the other hand, when the uppermost sheet 2 is not properly pressed against the pickup roller 105, the upper limit sensor 110 does not detect the uppermost sheet 2, and the output signal of the upper limit sensor 110 is at a low level. Note that when the upper limit sensor 110 detects the uppermost sheet 2, the output signal of the upper limit sensor 110 may be at a low level, and when the upper limit sensor 110 does not detect the uppermost sheet 2, the output signal of the upper limit sensor 110 may be at a high level.

[0037] The non-detection of the top sheet 2 by the upper limit sensor 110 causes the control unit 400 to operate the motor 104 of the lifter 103. The detection of the top sheet 2 by the upper limit sensor 110 causes the control unit 400 to stop the motor 104 of the lifter 103. Therefore, the lifter 103 lifts the placement table 102 until the top sheet 2 is pressed against the pick-up roller 105 with an appropriate pressure.

[0038] Here, if the upper limit sensor 110 fails, the lifter 103 does not operate normally, and the pressure with which the uppermost sheet 2 is pressed against the pickup roller 105 is low. In such a case, even if the supply motor 108 drives the pickup roller 105, the pickup roller 105 slips relative to the uppermost sheet 2. Therefore, the torque of the supply motor 108 is low, and the current waveform of the resistor 108b does not rise as much as in FIGS. 3 to 5.

[0039] The supply sensor 111 is disposed at a position downstream of the supply roller 4 in the transport direction of the sheet 2. The supply sensor 111 is a detection unit that detects the sheet 2 at that position.

[0040] The transport sensor 112 is disposed at a position downstream of the transport roller 120 in the transport direction of the sheet 2. The transport sensor 112 is a detection unit that detects the sheet 2 at that position.

[0041] The upper cassette 131, loading platform 132, lifter 133, motor 134, pickup roller 135, supply roller 136, supply motor 138, upper limit sensor 140, supply sensor 141 and transport sensor 142 are arranged in the same manner as the lower cassette 101, loading platform 102, lifter 103, motor 104, pickup roller 105, supply roller 106, supply motor 108, upper limit sensor 110, supply sensor 111 and transport sensor 112, respectively.

[0042] The printer main body 210 is installed inside the housing 10 and above the feeder 100. The printer main body 210 prints an image on a sheet fed by the feeder 100 and sends the printed sheet 2 to a discharge section 300.

[0043] The printer main body 210 has an exposure device 211, four developing devices 221-224, four photosensitive drums 231-234, four primary transfer rollers 241-244, a pair of timing rollers 250, a drive roller 251, a driven roller 252, a transfer belt 253, a secondary transfer roller 254, a fixing device 260, and a drive motor.

[0044] The exposure device 211 is installed inside the housing 10 and above the feeder 100. The exposure device 211 has four scanning type laser beam irradiators. The development devices 221-224 are arranged on the left and right above the exposure device 211. The development devices 221-224 contain yellow, magenta, cyan, and black toners, respectively. The photosensitive drums 231-234 are arranged on the left and right above the exposure device 211. The photosensitive drums 231-234 are provided on the development devices 221-224, respectively. The primary transfer rollers 241-244 are arranged on the left and right above the exposure device 211. The primary transfer rollers 241-244 are arranged on the photosensitive drums 231-234, respectively. The primary transfer rollers 241-244 are adjacent to the photosensitive drums 231-234, respectively. The secondary transfer roller 254 and the drive roller 251 are arranged above the timing roller 250. The driving roller 251 is driven by a driving motor. The secondary transfer roller 254 is disposed to the right of the driving roller 251. The secondary transfer roller 254 is pressed against the driving roller 251. The driven roller 252 is disposed to the left of the driving roller 251. The transfer belt 253 is provided in an endless shape. The transfer belt 253 is wound around the right driving roller 251 and the left driven roller 252 on the photosensitive drums 231 to 234. The transfer belt 253 is stretched between the driving roller 251 and the driven roller 252 in the left-right direction. The transfer belt 253 is passed between the primary transfer roller 241 and the photosensitive drum 231. The transfer belt 253 is passed between the primary transfer roller 242 and the photosensitive drum 232. The transfer belt 253 is passed between the primary transfer roller 243 and the photosensitive drum 233. The transfer belt 253 is passed between the primary transfer roller 244 and the photosensitive drum 234. The secondary transfer roller 254 is disposed to the right of the drive roller 251. The secondary transfer roller 254 is adjacent to the drive roller 251. The transfer belt 253 passes between the secondary transfer roller 254 and the drive roller 251.

[0045] The fixing device 260 is disposed above the secondary transfer roller 254 and the drive roller 251. The fixing device 260 has a fixing roller 261 and a pressure roller 262. The fixing roller 261 has a heater that heats the fixing roller 261. The pressure roller 262 is pressed against the fixing roller 261.

[0046] The discharge section 300 is disposed above the fixing device 260 and the transfer belt 253. The discharge section 300 has a discharge roller 301, a discharge tray 302, and a discharge motor. The discharge roller 301 is driven by the discharge motor. The discharge roller 301 is provided at a discharge port 303 above the fixing device 260. The discharge port 303 is formed in the housing 10 above the fixing device 260. The discharge tray 302 is provided on the top surface of the housing 10 to the left of the discharge port 303.

[0047] The exposure device 211 exposes the outer peripheral surfaces of the photosensitive drums 231 to 234. Exposing the photosensitive drum 231 by the exposure device 211 forms a yellow latent image on the outer peripheral surface of the photosensitive drum 231. Exposing the photosensitive drum 232 by the exposure device 211 forms a magenta latent image on the outer peripheral surface of the photosensitive drum 232. Exposing the photosensitive drum 233 by the exposure device 211 forms a cyan latent image on the outer peripheral surface of the photosensitive drum 233. Exposing the photosensitive drum 234 by the exposure device 211 forms a black latent image on the outer peripheral surface of the photosensitive drum 234. The latent images formed on the outer peripheral surfaces of the photosensitive drums 231 to 234 are charging patterns.

[0048] The developing devices 221-224 develop the latent images by attaching toner to the outer circumferential surfaces of the photosensitive drums 231-234, respectively. When the transfer belt 253 passes between the primary transfer roller 241 and the photosensitive drum 231, the primary transfer roller 241 attracts toner from the photosensitive drum 231 by the charge of the primary transfer roller 241, and transfers the yellow image to the transfer belt 253. Similarly, the primary transfer roller 242 transfers the magenta image from the photosensitive drum 232 to the transfer belt 253 by the charge of the primary transfer roller 242. The primary transfer roller 243 transfers the cyan image from the photosensitive drum 233 to the transfer belt 253 by the charge of the primary transfer roller 243. The primary transfer roller 244 transfers the black image from the photosensitive drum 234 to the transfer belt 253 by the charge of the primary transfer roller 244.

[0049] The timing roller 250 synchronizes the sheet 2 supplied by the feeder 100 with the transfer belt 253 and sends the sheet 2 to the secondary transfer roller 254. When the transfer belt 253 and the sheet 2 pass between the secondary transfer roller 254 and the drive roller 251, the secondary transfer roller 254 attracts toner from the transfer belt 253 by the charge of the secondary transfer roller 254, and transfers the image made of toner onto the sheet 2.

[0050] The fixing device 260 fixes the image onto the sheet 2 sent from the secondary transfer roller 254. Specifically, when the sheet 2 passes between the fixing roller 261 and the pressure roller 262, the heat of the fixing roller 261 melts the toner, and the pressure of the pressure roller 262 and the fixing roller 261 causes the toner to adhere to the sheet 2. As a result, the image is fixed onto the sheet 2.

[0051] The discharge section 300 discharges the sheet 2 sent from the fixing roller 261. Specifically, the discharge rollers 301 pass the sheet 2 through the discharge port 303, and the sheet 2 that has passed through the discharge port 303 is discharged onto the discharge tray 302. As a plurality of sheets 2 are printed one after another, the sheets 2 are stacked on the discharge tray 302.

[0052] <2. Printing Operation of Image Forming Device> The following describes the printing operation of the image forming apparatus 1. The printing operation of the image forming apparatus 1 described below may be in any one of a normal copy mode, a normal printing mode, a test printing mode, a test copy mode, and a diagnostic mode.

[0053] (1) Sheet supply When the control unit 400 acquires print job data during copying or printing, it periodically operates the supply motor 108 via the motor driver 108a. As a result, the pickup roller 105 sends the topmost sheet 2 out of the stacked multiple sheets 2 one by one to the supply roller 106 and the separation roller 107, and the supply roller 106 sends the topmost sheet 2 one by one to the transport roller 120, and the separation roller 107 separates the topmost sheet 2 from the sheet 2 below it.

[0054] (2) Printing and discharging sheets In parallel with controlling the supply motor 108, the control unit 400 synchronizes the conveyance motor 121, the printer body 210, and the discharge unit 300 with the conveyance of the sheet 2 based on signals from the supply sensor 111 and the conveyance sensors 112 and 142. As a result, the printer body 210 prints images on the sheets 2 one by one, and the discharge unit 300 discharges the sheets 2 one by one.

[0055] (3) Lifting of the platform and sheet stack During printing, the control unit 400 monitors the output signal of the upper limit sensor 110. When some sheets 2, for example 10 sheets, are sent out from the placement table 102 during printing, the upper limit sensor 110 no longer detects the top sheet 2 on the placement table 102. Therefore, the output signal of the upper limit sensor 110 switches from high level to low level. Then, the control unit 400 activates the motor 104 of the lifter 103, and the lifter 103 lifts the placement table 102. Thereafter, when the upper limit sensor 110 detects the top sheet 2, the output signal of the upper limit sensor 110 switches from low level to high level. Then, the control unit 400 stops the motor 104 of the lifter 103.

[0056] (4) Processing during printing During printing, each time the sheet 2 is sent out by the pickup roller 105 and the supply roller 106, that is, each time the supply sensor 111 detects the sheet 2 and the output signal of the supply sensor 111 rises from a low level to a high level, the control unit 400 executes the following processes (4-1) to (4-12).

[0057] (4-1) Increment the print amount The control unit 400 updates the number of periodic operations of the supply motor 108, i.e., the number of printed sheets of sheet 2. Specifically, each time the supply sensor 111 or the transport sensor 112 detects the sheet 2 and causes the output signal of the supply sensor 111 or the transport sensor 112 to rise from low to high, the control unit 400 increments the printed sheet value. The printed sheet value here refers to the number of printed sheets of sheet 2 that have been printed since the start of printing. At the start of printing, the control unit 400 resets the printed sheet value to zero.

[0058] (4-2) Increment the total number of printed sheets The control unit 400 updates the total number of printed sheets 2. Specifically, each time the supply sensor 111 or the transport sensor 112 detects a sheet 2 and causes the output signal of the supply sensor 111 or the transport sensor 112 to rise from low to high, the control unit 400 increments the total number. The total number here refers to the total number of sheets 2 that have been printed since the start of the initial printing. Note that the control unit 400 does not reset the total number at the start of printing.

[0059] (4-3) Calculating the average torque of the supply motor During printing, the control unit 400 monitors the torque of the supply motor 108. That is, the control unit 400 monitors the output signal of the low-pass filter 108d. At this time, the control unit 400 discretizes the output signal of the low-pass filter 108d at a sampling frequency of, for example, 1 kHz, and processes the discretized data string. Specifically, every time the output signal of the supply sensor 111 rises from a low level to a high level as a result of the supply sensor 111 detecting the sheet 2, the control unit 400 calculates a time average value of the torque of the supply motor 108 for a certain period, for example, 10 milliseconds. That is, the control unit 400 calculates an average value of, for example, 100 pieces of data for a certain period from the discretized data string. Hereinafter, the average value calculated in this manner is referred to as the torque average value. The certain period is, for example, the period T shown in FIG. 3.

[0060] (4-4) Calculating the maximum amplitude of the torque ripple of the supply motor Each time the supply sensor 111 detects the sheet 2 and the output signal of the supply sensor 111 rises from low level to high level, the control unit 400 calculates the difference between the maximum and minimum torque values ​​of the supply motor 108 for a fixed period, such as 10 milliseconds. That is, the control unit 400 extracts the maximum and minimum values ​​from, for example, 100 pieces of data for the fixed period of time from the discretized data string, and calculates the difference between them. Hereinafter, the difference calculated in this way is referred to as the ripple maximum amplitude value. The fixed period is, for example, the period T shown in FIG. 3.

[0061] (4-5) Timing of the first duration During printing, the control unit 400 monitors the output signal of the supply sensor 111. Each time the supply sensor 111 detects the sheet 2 and the output signal of the supply sensor 111 rises from a low level to a high level, the control unit 400 measures the period until the supply sensor 111 detects the sheet 2. In other words, the control unit 400 measures the period from when the supply sensor 111 becomes high level one time before to when the supply sensor 111 becomes high level thereafter. The control unit 400 may also measure the period from when the supply sensor 111 becomes low level one time before to when the supply sensor 111 becomes high level thereafter. These periods correspond to the periods during which the sheet 2 is transported by the supply roller 106. Hereinafter, these periods are referred to as first durations.

[0062] (4-6) Memory of maximum ripple amplitude, first duration and total amount Each time the supply sensor 111 detects the sheet 2 and the output signal of the supply sensor 111 rises from a low level to a high level, the control unit 400 associates the ripple maximum amplitude value, the first duration, and the total number of sheets with each other. Furthermore, the control unit 400 stores the associated ripple maximum amplitude value, the first duration, and the total number of sheets in chronological order.

[0063] (4-7) Check the quality of the supply roller and separation roller The control unit 400 determines whether the supply roller 106 and the separation roller 107 are defective or defective based on the maximum ripple amplitude value and the first duration associated with each other in (4-6) above.

[0064] Specifically, the control unit 400 compares the ripple maximum amplitude value associated in (4-6) above with a predetermined first threshold value. The control unit 400 compares the first duration associated in (4-6) above with a predetermined second threshold value. If the ripple maximum amplitude value is equal to or greater than the first threshold value and the first duration is equal to or greater than the predetermined second threshold value, the control unit 400 determines that the supply roller 106 is defective. If the ripple maximum amplitude value is equal to or greater than the first threshold value and the first duration is less than the predetermined second threshold value, the control unit 400 determines that the separation roller 107 is defective. If the ripple maximum amplitude value is less than the first threshold value, the control unit 400 determines that the supply roller 106 and the separation roller 107 are good.

[0065] If it is determined that the supply roller 106 is defective, the control unit 400 may cause the display unit 410 to display a message indicating that the supply roller 106 is defective. If separation roller 107 is determined to be defective, control unit 400 may cause display unit 410 to display the fact that separation roller 107 is defective. If the supply roller 106 or the separation roller 107 is determined to be defective, the control unit 400 may stop the operation of the feeder 100, the printer body 210, and the discharge unit 300.

[0066] (4-8) Timing of the second duration During printing, the control unit 400 monitors the output signal of the transport sensor 112. Each time the sheet 2 is sent out by the pickup roller 105 and the supply roller 106, for example, each time the transport sensor 112 detects the sheet 2, the control unit 400 measures the period until the transport sensor 112 detects the sheet 2. In other words, the control unit 400 measures the period from when the supply sensor 111 becomes high level one time previously to when the transport sensor 112 becomes high level thereafter. The control unit 400 may also measure the period from when the transport sensor 112 becomes low level one time previously to when the transport sensor 112 becomes high level thereafter. These periods correspond to the periods during which the sheet 2 is transported by the supply roller 106. Hereinafter, these periods are referred to as second durations.

[0067] (4-9) Memory of maximum ripple amplitude, second duration and total amount Each time the supply sensor 111 detects the sheet 2 and the output signal of the supply sensor 111 rises from a low level to a high level, the control unit 400 associates the ripple maximum amplitude value, the second duration, and the total number of sheets with each other. Furthermore, the control unit 400 stores the associated ripple maximum amplitude value, the second duration, and the total number of sheets in chronological order.

[0068] (4-10) Check the quality of the supply roller and separation roller The control unit 400 determines whether the supply roller 106 and the separation roller 107 are good or bad, based on the ripple maximum amplitude value and the second duration associated with each other in (4-9) above.

[0069] Specifically, the control unit 400 compares the ripple maximum amplitude value associated in (4-9) above with a predetermined first threshold value. The control unit 400 compares the second duration associated in (4-9) above with a predetermined second threshold value. If the ripple maximum amplitude value is equal to or greater than the first threshold value and the second duration is equal to or greater than the predetermined second threshold value, the control unit 400 determines that the supply roller 106 is defective. If the ripple maximum amplitude value is equal to or greater than the first threshold value and the first duration is less than the predetermined second threshold value, the control unit 400 determines that the separation roller 107 is defective. If the ripple maximum amplitude value is less than the first threshold value and the first duration is less than the predetermined second threshold value, the control unit 400 determines that the supply roller 106 and the separation roller 107 are good.

[0070] If it is determined that the supply roller 106 is defective, the control unit 400 may cause the display unit 410 to display a message indicating that the supply roller 106 is defective. If separation roller 107 is determined to be defective, control unit 400 may cause display unit 410 to display the fact that separation roller 107 is defective. If the supply roller 106 or the separation roller 107 is determined to be defective, the control unit 400 may stop the operation of the feeder 100, the printer body 210, and the discharge unit 300.

[0071] (4-11) Storage of the upper limit sensor output signal level, average torque value, and total number During printing, the control unit 400 monitors the output signal of the upper limit sensor 110. Each time the supply sensor 111 detects a sheet 2 and the output signal of the supply sensor 111 rises from low to high, the control unit 400 associates the level of the output signal of the upper limit sensor 110 at the time of calculating the torque average value with the torque average value and the total sheet value. Furthermore, the control unit 400 stores the associated levels, torque average values, and total sheet value in chronological order.

[0072] (4-12) Checking the quality of the upper limit sensor The control unit 400 judges whether the upper limit sensor 110 is good or bad based on the average torque value associated with the level of the output signal of the upper limit sensor 110 in the above (4-11).

[0073] Specifically, the control unit 400 compares the torque average value associated in (4-11) above with a predetermined third threshold value. Furthermore, the control unit 400 determines whether the level of the output signal of the upper limit sensor 110 associated in (4-11) above is high or low. If the torque average value is less than the third threshold value and the level of the output signal of the upper limit sensor 110 is high, the control unit 400 determines that the upper limit sensor 110 is defective. If the torque average value is equal to or greater than the third threshold value, or if the level of the output signal of the upper limit sensor 110 is low, the control unit 400 determines that the upper limit sensor 110 is good.

[0074] If it is determined that the upper limit sensor 110 is defective, the control unit 400 may cause the display unit 410 to display a message indicating that the upper limit sensor 110 is defective. If the upper limit sensor 110 is determined to be defective, the control unit 400 may stop the operation of the feeder 100, the printer body 210, and the discharge unit 300.

[0075] (5) Printing complete When the incremented print amount in (4-1) above reaches the number of sheets specified in the print job data, the control unit 400 stops the operation of the feeder 100, the printer main body 210, and the discharge unit 300, in that order.

[0076] (6) Data transmission After printing is completed, the control unit 400 transmits the time series of the maximum ripple amplitude value, the first duration, and the total amount value, which have been associated with each other in the above (4-6), to the external server 450. When the external server 450 receives the time series of the maximum ripple amplitude value, the first duration, and the total amount value, it stores the received time series so as to add the received time series to the time series stored up to that point. Note that, during printing, the control unit 400 may transmit the maximum ripple amplitude value, the first duration, and the total amount value, which have been associated with each other in the above (4-6), to the external server 450, and the external server 450 may store the maximum ripple amplitude value, the first duration, and the total amount value in chronological order.

[0077] The control unit 400 transmits the time series of the maximum ripple amplitude value, the second duration, and the total amount value, which are associated with each other in the above (4-9), to the external server 450. When the external server 450 receives the time series of the maximum ripple amplitude value, the second duration, and the total amount value, it stores the received time series so as to add the received time series to the time series stored up to that point. Note that during printing, the control unit 400 may transmit the maximum ripple amplitude value, the second duration, and the total amount value, which are associated with each other in the above (4-9), to the external server 450, and the external server 450 may store the maximum ripple amplitude value, the second duration, and the total amount value in chronological order.

[0078] The control unit 400 transmits the time series of the level, average torque value, and total sheet value associated with each other in the above (4-11) to the external server 450. When the external server 450 receives the time series of the level, average torque value, and total sheet value, it stores the received time series so as to add the received time series to the time series stored up to that point. Note that during printing, the control unit 400 may transmit the level, average torque value, and total sheet value associated with each other in the above (4-11) to the external server 450, and the external server 450 may store the level, average torque value, and total sheet value in chronological order.

[0079] <3. Processing of external servers> The external server 450 reads the last associated maximum ripple amplitude value and first duration from the stored time series of the maximum ripple amplitude value, the first duration, and the total number of sheets. The external server 450 judges the quality of the supply roller 106 and the separation roller 107 based on the last maximum ripple amplitude value and the first duration. The judgment process of the external server is the same as the judgment process of the control unit 400 in the above (4-7).

[0080] The external server 450 reads the last associated maximum ripple amplitude value and second duration from the stored time series of the maximum ripple amplitude value, the second duration, and the total number of sheets. The external server 450 judges the quality of the supply roller 106 and the separation roller 107 based on the last maximum ripple amplitude value and the second duration. The judgment process of the external server is the same as the judgment process of the control unit 400 in the above (4-10).

[0081] The external server 450 reads the last associated level and average torque value from the stored time series of level, average torque value, and total amount. The external server 450 judges the quality of the upper limit sensor 110 based on the last level and average torque value. The judgment process of the external server 450 is the same as the judgment process of the control unit 400 in the above (4-12).

[0082] <4. Regarding the quality of the supply roller and separation roller> The reason why the quality of the supply roller 106 and the separation roller 107 can be determined based on the maximum ripple amplitude value and the first duration as described above in (4-7) will be described with reference to FIGS.

[0083] When both the supply roller 106 and the separation roller 107 are in good condition, the top sheet 2 is fed by the supply roller 106, and the sheet 2 below it is returned by the separation roller 107. A good supply roller 106 does not slip relative to the top sheet 2. A good separation roller 107 does not slip relative to the sheet 2 below the top sheet 2. Therefore, the torque ripple component is small, and the ripple maximum amplitude value is less than the first threshold value. The period during which the sheet 2 is transported by the supply roller 106, i.e., the first duration, is less than the second threshold value.

[0084] When the supply roller 106 is deteriorated by dust such as paper powder, the supply roller 106 slips with respect to the sheet 2. Such slippage increases the torque ripple component, and the maximum ripple amplitude value becomes equal to or exceeds the first threshold value, as shown in Figures 6 and 7. The same applies when the separation roller 107 is deteriorated.

[0085] However, if the ripple maximum amplitude value is equal to or greater than the first threshold value, it is not possible to determine whether the supply roller 106 or the separation roller 107 has deteriorated. Therefore, the first duration is used as a determination factor. When the supply roller 106 deteriorates, the supply roller 106 slips against the sheet 2, so that it takes a long time for the sheet 2 fed by the supply roller 106 to be detected by the supply sensor 111. Therefore, as shown in FIG. 6, deterioration of the supply roller 106 causes the first duration to be equal to or greater than the second threshold value. Even if the separation roller 107 slips against the sheet 2 below the top sheet 2 due to deterioration, it takes a short time for the sheet 2 fed by the supply roller 106 to be detected by the supply sensor 111. Therefore, as shown in FIG. 7, deterioration of the separation roller 107 does not cause the first duration to be equal to or greater than the second threshold value.

[0086] <5. Upper limit sensor quality> As described above in (4-12), the reason why the quality of the upper limit sensor 110 can be determined based on the average torque value and the level of the output signal of the upper limit sensor 110 will be described with reference to Figures 8 and 9. Here, Figures 8 and 9 are graphs showing changes in the output signal of the upper limit sensor 110 and the average torque value as printing progresses. In Figures 8 and 9, the horizontal axis indicates the number of printed sheets 2, and the vertical axis indicates the output signal of the upper limit sensor 110 and the average torque value.

[0087] When the upper limit sensor 110 is in a normal state, the sheets 2 are successively sent out from the mounting table 102 during printing, so that the output signal of the upper limit sensor 110 periodically drops to a low level as shown in Fig. 8. Here, the range of the horizontal axis in Fig. 8 and Fig. 9 corresponds to approximately one cycle.

[0088] When the output signal of the upper limit sensor 110 drops to a low level, the pressure with which the top sheet 2 is pressed against the pick-up roller 105 drops. Therefore, the torque average value drops. Even so, the low level of the output signal of the upper limit sensor 110 causes the control unit 400 to operate the motor 104 of the lifter 103. Therefore, the torque average value rises before dropping to the third threshold value.

[0089] On the other hand, when the upper limit sensor 110 is defective, even if the sheets 2 are sent out one after another from the placement table 102 during printing, as shown in FIG. 9, the output signal of the upper limit sensor 110 does not periodically decrease, and the output signal of the upper limit sensor 110 remains at a high level. Therefore, the lifter 103 does not operate, and the pressure with which the uppermost sheet 2 is pressed against the pick-up roller 105 continues to decrease to the third threshold. Therefore, the torque average value being less than the third threshold and the output signal of the upper limit sensor 110 being at a high level means that the upper limit sensor 110 is defective. Here, even if the transmission mechanism from the supply motor 108 to the pick-up roller 105 or the lifter 103 is defective, the torque average value may be less than the third threshold. Therefore, the upper limit sensor 110 cannot be identified as defective just because the torque average value is less than the third threshold. However, since the output signal of the upper limit sensor 110 is used as a determining factor in addition to the average torque value, a faulty upper limit sensor 110 can be identified among the components related to lifting the sheet stack 3 and transporting the topmost sheet 2 .

[0090] <6. Summary> As described above, the torque detection unit 108s detects the torque of the supply motor 108 and outputs a signal indicating the detected torque to the control unit 400. Every time the sheet 2 is fed by the pickup roller 105 and the supply roller 106, the control unit 400 calculates the maximum ripple amplitude value from the output signal of the torque detection unit 108s. The supply sensor 111 detects the sheet 2 fed by the pickup roller 105 and the supply roller 106. Every time the sheet 2 is fed by the pickup roller 105 and the supply roller 106, the control unit 400 calculates the first duration from the output signal of the supply sensor 111. The control unit 400 compares the maximum ripple amplitude value and the first duration with a first threshold value and a second threshold value, respectively. If the comparison result shows that the maximum ripple amplitude value is equal to or greater than the first threshold value and the first duration is equal to or greater than the second threshold value, the control unit 400 determines that the supply roller 106 is defective. If the comparison result shows that the maximum ripple amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, the control unit 400 determines that the separation roller 107 is defective. If the comparison result shows that the maximum ripple amplitude value is less than the first threshold value, the control unit 400 determines that the supply roller 106 and the separation roller 107 are good. Using the first duration in addition to the maximum ripple amplitude value as a determination factor contributes to identifying a defective part among the supply roller 106 and the separation roller 107.

[0091] The control unit 400 monitors the output signal of the upper limit sensor 110. Each time the control unit 400 sends out the sheet 2 by the pick-up roller 105 and the feed roller 106, the control unit 400 calculates the torque average value from the output signal of the torque detection unit 108s. The control unit 400 compares the torque average value with a third threshold value. If the comparison result shows that the torque average value is equal to or greater than the third threshold value, or if the output signal of the upper limit sensor 110 is low when the sheet 2 is sent out by the pick-up roller 105 and the feed roller 106, the control unit 400 judges the upper limit sensor 110 to be good. If the comparison result shows that the torque average value is equal to or greater than the third threshold value and if the output signal of the upper limit sensor 110 is high when the sheet 2 is sent out by the pick-up roller 105 and the feed roller 106, the control unit 400 judges the upper limit sensor 110 to be defective. Using the output signal of the upper limit sensor 110 in addition to the torque average value as a judgment factor contributes to identifying a defective upper limit sensor 110 among the components related to lifting the sheet stack 3 and conveying the top sheet 2. [Explanation of symbols]

[0092] 1. Image forming device 2 seats 3 Sheet Stack 100 Feeder 102 Placement table 103 Lifter 104 Motor 105 Pickup roller 106 Supply roller 107 Separation roller 108 Supply motor 108s Torque detector 110 Upper limit sensor (detection part) 111 Supply sensor (detection unit) 112 Transport sensor (detection unit) 400 Control section 450 External Server

Claims

1. a conveying unit that conveys the topmost sheet of the stacked sheets; A supply motor that drives the conveying unit; a detection unit that detects the topmost sheet; A torque detection unit that detects the torque of the supply motor; a control unit that identifies a defective part from among parts related to conveyance of the sheet based on a detection result of the detection unit and a detection result of the torque detection unit; An image forming apparatus comprising:

2. The conveying unit is a pick-up roller for feeding the topmost sheet from the plurality of sheets; a feed roller disposed downstream of the pickup roller and feeding the topmost sheet fed by the pickup roller; a separation roller disposed downstream of the pickup roller and configured to separate the top sheet fed by the feed roller from the sheet therebelow; having the parts relating to the conveyance of the sheet include the supply roller and the separation roller, the supply motor drives the pickup roller, the supply roller, and the separation roller; the detection unit is disposed downstream of the supply roller and the separation roller, the torque detection unit outputs an output signal representing the torque of the supply motor to the control unit; The control unit calculates a maximum amplitude value of a ripple component of the output signal of the torque detection unit, the control unit calculates a duration during which the detection unit detects the uppermost sheet, and the control unit determines whether the supply roller and the separation roller are good or bad based on the maximum amplitude value and the duration. The image forming apparatus according to claim 1 .

3. The control unit compares the maximum amplitude value and the duration with a first threshold and a second threshold, respectively; When the comparison result indicates that the maximum amplitude value is equal to or greater than the first threshold value and the duration is equal to or greater than the second threshold value, the control unit determines that the supply roller is defective, When the comparison result indicates that the maximum amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, the control unit determines that the separation roller is defective, If the comparison result indicates that the maximum amplitude value is less than the first threshold value, the control unit determines that the supply roller and the separation roller are in good condition. The image forming apparatus according to claim 2 .

4. The conveying unit is a placement table on which the plurality of sheets are placed; a pick-up roller for feeding the topmost sheet from the plurality of sheets; a lifter that lifts the placement table toward the pickup roller when the detection unit does not detect the top sheet and stops lifting the placement table when the detection unit detects the top sheet; having the component relating to the conveyance of the sheet includes the detection unit, the feed motor drives the pick-up roller; The detection unit is disposed at the same height as the pickup roller, the torque detection unit outputs an output signal representing the torque of the supply motor to the control unit; The control unit calculates an average value of the output signal of the torque detection unit when the top sheet is fed by the pickup roller, and judges the quality of the detection unit based on the average value and a detection result of the detection unit. The image forming apparatus according to claim 1 .

5. The control unit compares the average value with a predetermined threshold value; If the comparison result indicates that the average value is equal to or greater than the threshold value, or the detection result of the detection unit indicates that the previous topmost sheet has not been detected, the control unit determines that the detection unit is in a good condition; If the comparison result indicates that the average value is less than the threshold value and the detection result of the detection unit is the detection of the top sheet, the control unit determines that the detection unit is defective. The image forming apparatus according to claim 4 .

6. a pickup roller that feeds the topmost sheet out of the stack of sheets one by one; a feed roller disposed downstream of the pickup roller and feeding the topmost sheet fed by the pickup roller; a separation roller disposed downstream of the pickup roller and configured to separate the top sheet fed by the feed roller from the sheet therebelow; a supply motor that drives the pickup roller, the supply roller, and the separation roller; a detection unit disposed downstream of the supply roller and the separation roller, the detection unit detecting the uppermost sheet fed by the supply roller; a torque detection unit that detects a torque of the supply motor and outputs an output signal representing the torque of the supply motor; a control unit that calculates a maximum amplitude value of a ripple component of the output signal of the torque detection unit and calculates a duration of detection of the top sheet by the detection unit every time the detection unit detects the top sheet, The control unit transmits the maximum amplitude value and the duration to an information processing device in association with each other. Feeder.

7. An information processing device capable of communicating with the control unit of the feeder according to claim 6, a receiving process for receiving the maximum amplitude value and the duration transmitted by the control unit; a comparison process of comparing the maximum amplitude value and the duration with a first threshold and a second threshold, respectively; a determination process in which, when the result of the comparison process shows that the maximum amplitude value is equal to or greater than the first threshold value and the duration is equal to or greater than the second threshold value, the control unit determines that the supply roller is defective, when the maximum amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, the control unit determines that the separation roller is defective, and when the maximum amplitude value is less than the first threshold value, the control unit determines that the supply roller and the separation roller are good; An information processing device that executes the above.

8. a pickup roller that feeds the topmost sheet out of the stack of sheets one by one; a feed roller disposed downstream of the pickup roller and feeding the topmost sheet fed by the pickup roller; a separation roller disposed downstream of the pickup roller and configured to separate the top sheet fed by the feed roller from the sheet therebelow; a supply motor that drives the pickup roller, the supply roller, and the separation roller; a detection unit disposed downstream of the supply roller and the separation roller, the detection unit detecting the uppermost sheet fed by the supply roller; a torque detection unit that detects the torque of the supply motor and outputs an output signal representing the torque; A control unit, The control unit: a calculation process for calculating a maximum amplitude value of a ripple component of the output signal of the torque detection unit and calculating a duration of detection of the uppermost sheet by the detection unit every time the detection unit detects the uppermost sheet; a comparison process of comparing the maximum amplitude value and the duration with a first threshold and a second threshold, respectively; a determination process for determining that the supply roller is defective when the maximum amplitude value is equal to or greater than the first threshold value and the duration is equal to or greater than the second threshold value, determining that the separation roller is defective when the maximum amplitude value is equal to or greater than the first threshold value and the duration is less than the second threshold value, and determining that the supply roller and the separation roller are good when the maximum amplitude value is less than the first threshold value; Run Feeder.

9. a placement table on which the stacked sheets are placed; a pickup roller for feeding the topmost sheet of the plurality of sheets one by one; a detection unit that is disposed at the same height as a position where the pickup roller is provided and detects the topmost sheet; A supply motor that drives the pickup roller; a torque detection unit that detects the torque of the supply motor and outputs an output signal representing the torque; a lifter that lifts the placement table toward the pickup roller when the detection unit does not detect the top sheet and stops lifting the placement table when the detection unit detects the top sheet; a control unit that calculates an average value of a ripple component of the output signal of the torque detection unit every time the topmost sheet is sent out by the pickup roller, The control unit transmits to an information processing device a detection result of the detection unit at the time of calculating the average value and the average value in association with each other. Feeder.

10. An information processing device capable of communicating with the control unit of the feeder according to claim 9, a receiving process for receiving the detection result and the average value transmitted by the control unit; a comparison process for comparing the average value with a predetermined threshold value; a determination process for determining the detection unit as good if the average value is equal to or greater than the threshold value or the detection result is non-detection of the top sheet as a result of the comparison process, and determining the detection unit as bad if the average value is less than the threshold value and the detection result is detection of the top sheet; An information processing device that executes the above.

11. a placement table on which the stacked sheets are placed; a pickup roller for feeding the topmost sheet of the plurality of sheets one by one; a detection unit that is disposed at the same height as a position where the pickup roller is provided and detects the topmost sheet; A supply motor that drives the pickup roller; a torque detection unit that detects the torque of the supply motor and outputs an output signal representing the torque; a lifter that lifts the placement table toward the pickup roller when the detection unit does not detect the top sheet and stops lifting the placement table when the detection unit detects the top sheet; A control unit, The control unit: a calculation process of calculating an average value of a ripple component of the output signal of the torque detection unit every time the topmost sheet is sent out by the pickup roller; a comparison process for comparing the average value with a predetermined threshold value; a determination process for determining the detection unit as good if the average value is equal to or greater than the threshold value or the detection result of the detection unit is non-detection of the uppermost sheet as a result of the comparison process, and determining the detection unit as bad if the average value is less than the threshold value and the detection result is detection of the uppermost sheet; Run Feeder.

Images