JP2020090380A - Image formation device - Google Patents

Abstract

To provide an image formation device which, when an abnormality has caused in a detection result of a double-feed detection sensor, can specify the cause.SOLUTION: An image formation device 101 comprises: an image formation part 20 which forms an image on a sheet conveyed through a horizontal path 40; a double-feed detection sensor 30 for detecting a condition where a plurality of sheets conveyed through the horizontal path 40 are conveyed while being overlapped; and conveyance detection sensors 31, 32 for detecting a residual material of the horizontal path 40. The image formation device 101 determines abnormality of a detection result of the double-feed detection sensor 30 before conveyance of the sheet is started. When the detection result is abnormal, the image formation device 101, based on the detection result of the conveyance detection sensors 31, 32, determines which of the abnormality of the double-feed detection sensor 30, the residual material of the horizontal path 40, and the abnormality of the conveyance detection sensors 31, 32 the cause of the abnormality is.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus that forms an image on a sheet, such as a printer, a copying machine, and a multifunction peripheral.

The image forming apparatus forms an image while feeding the sheets one by one. When a plurality of sheets are conveyed in an overlapping manner, the image forming apparatus cannot perform normal image formation on the sheets and discharges a product containing, for example, a blank sheet. Further, when a plurality of sheets are overlapped and conveyed, the sheets may be wound around the fixing unit or the fixing device in the image forming apparatus, and the image forming apparatus may malfunction. Conveying sheets in the state of overlapping multiple sheets is called "double feeding".

Patent Document 1 discloses an image forming apparatus including a sensor for detecting double feed in a sheet conveyance path. When the image forming apparatus detects a double feed, it stops the conveyance of the sheet and discharges the sheet to the tray for abnormal discharge. As a sensor that detects double feed, there is a double feed detection sensor that uses ultrasonic waves, for example. The double feed detection sensor using ultrasonic waves has an ultrasonic wave transmitting unit and an ultrasonic wave receiving unit. The receiving unit receives the ultrasonic wave output from the transmitting unit. The double feeding of the sheet is detected based on the detection result of the double feeding detection sensor indicating the intensity of the ultrasonic wave received by the receiving unit.

JP, 2018-95424, A

In order to accurately detect the double feed, the double feed detection sensor is checked for a failure before use. The failure of the double feed detection sensor can be confirmed by transmitting the ultrasonic wave from the transmitter and checking the intensity (reception level) of the ultrasonic wave received by the receiver when the object to be detected is not in the detection position of the double feed sensor. To be judged. When the reception level is lower than the threshold for failure determination, the failure of the double feed detection sensor is determined. That is, when the detection result of the double feed detection sensor is lower than the threshold value, it is determined that the detection result of the double feed detection sensor is abnormal. However, the reception level similarly decreases when there is a residue at the detection position and when the transmitter or the receiver itself fails. Therefore, even if the detection result (reception level) according to the intensity of the ultrasonic wave received by the receiving unit is less than or equal to the threshold value, the cause is the failure of the double-feed detection sensor itself or the residue at the detection position. It is unknown whether it is a thing.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide an image forming apparatus capable of identifying the cause of an abnormality in the detection result of the double feed detection sensor. ..

The image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet conveyed through a conveyance path, and a double-feed detection for detecting a state where a plurality of sheets conveyed through the conveyance path are conveyed in an overlapping manner. Means, a conveyance detecting means for detecting the presence/absence of a sheet in the conveyance path, and an abnormality in the detection result of the double feed detecting means before starting the conveyance of the sheet, and the detection result is abnormal. In this case, based on the detection result of the conveyance detection unit, the cause of the abnormality is an abnormality of the double feed detection unit, a residue of the conveyance path, or an abnormality of the conveyance detection unit. And a determination means for determining whether or not.

According to the present invention, when an abnormality occurs in the detection result of the double feed detection means, it is possible to accurately specify whether the cause is a failure of the double feed detection means or a residue at the detection position. it can.

FIG. 1 is a configuration diagram of an image forming apparatus. The structural example figure of a controller. Explanatory drawing of a double feed detection sensor. 9 is a flowchart showing a failure detection process of the double feed detection sensor. (A)-(d) is explanatory drawing of the failure detection of a double feed detection sensor. FIG.

An image forming apparatus of the present invention will be described with reference to the drawings.

(Image forming device)
FIG. 1 is a configuration diagram of the image forming apparatus of the present embodiment. The image forming apparatus 101 includes one or more paper feed stages 14 that accommodate sheets on which images are formed. The sheet is fed from the paper feed stage 14, and an image is formed while being conveyed through the conveyance path. The transport path includes a vertical path 41 and a horizontal path 40. The image forming apparatus 101 includes a pickup roller 15 and a separation roller 16 in order to separate and feed sheets one by one from the paper feed stage 14 to the transport path (vertical path 41). The pickup roller 15 feeds the sheet from the paper feed stage 14. The separation roller 16 separates the sheets fed by the pickup roller 15 one by one. A vertical pass roller 17 is provided in the vertical pass 41. The vertical pass roller 17 conveys the sheet conveyed by the separation roller 16 to the horizontal pass 40.

The registration roller 11 is provided on the horizontal path 40. The horizontal path 40 between the vertical path roller 17 and the registration roller 11 is provided with a conveyance detection sensor 31 and a double feed detection sensor 30 in close proximity to each other in order from the upstream side in the sheet conveyance direction. The conveyance detection sensor 31 detects the presence/absence of a sheet conveyed on the horizontal path 40. Even if there is a residue other than the sheet at the position of the conveyance detection sensor 31, the conveyance detection sensor 31 outputs a signal indicating that the sheet exists. The sheet conveyance timing and the image formation timing are adjusted according to the detection result of the conveyance detection sensor 31. The multi-feed detection sensor 30 is used to detect whether or not a plurality of sheets conveyed on the horizontal path 40 are conveyed in an overlapped state in a multi-feed state. The double feed detection sensor 30 detects double feed using ultrasonic waves.

The registration roller 11 corrects skew of the sheet conveyed on the horizontal path 40 with respect to the conveying direction. A conveyance detection sensor 32 is provided downstream of the registration rollers 11 in the sheet conveyance direction. The conveyance detection sensor 32 detects a sheet conveyed on the horizontal path 40. Even when there is a residue other than the sheet at the position of the conveyance detection sensor 32, the conveyance detection sensor 32 outputs a signal indicating that the sheet exists. The sheet conveyance timing and the image formation timing are adjusted according to the detection result of the conveyance detection sensor 32. In the horizontal path 40, a secondary transfer unit 21, a fixing device 12, and a discharge roller 13 are sequentially provided on the downstream side of the transport detection sensor 32 in the sheet transport direction. Hereinafter, the residue will be described as including the sheet remaining in the transport path.

The image formation is performed by the image forming unit 20. The image forming unit 20 includes drums 22 to 25 on which toner images of different colors are formed and an intermediate transfer member 26. The intermediate transfer member 26 is rotating and is sequentially transferred from the drums 22 to 25 so that the toner images of the respective colors are superposed. By being superposed and transferred, a full-color toner image is formed on the intermediate transfer member 26. The full-color toner image is conveyed to the secondary transfer portion 21 by the rotation of the intermediate transfer member 26.

The registration roller 11 conveys the sheet to the secondary transfer portion 21 at the timing when the full-color toner image is conveyed to the secondary transfer portion 21. The secondary transfer unit 21 transfers the toner image formed on the intermediate transfer body 26 onto a sheet. The sheet onto which the toner image has been transferred is conveyed from the secondary transfer unit 21 to the fixing device 12. The fixing device 12 fixes the toner image on the sheet by heating and pressing the sheet on which the toner image is transferred. The fixing device 12 conveys the sheet on which the toner image is fixed to the discharge roller 13. The discharge roller 13 discharges the sheet (resultant) on which the toner image is fixed to the outside of the image forming apparatus 101.

The image forming apparatus 101 as described above includes an operation unit 306 serving as a user interface. The operation unit 306 is configured by combining an input device such as various key buttons and a touch panel and an output device such as a display and a speaker. The operation unit 306 receives a user's operation using the input device. The operation unit 306 displays information such as the operating state of the image forming apparatus 101 on the display and outputs a warning sound or the like from the speaker.

FIG. 2 is an exemplary configuration diagram of a controller that controls the operation of the image forming apparatus 101. The controller includes a main control unit 200 and a printer control unit 201.

The main control unit 200 is an information processing device including a CPU (Central Processing Unit) 301, a RAM (Random Access Memory) 302, and a ROM (Read Only Memory) 303. The CPU 301, RAM 302, and ROM 303 are connected via a bus. The CPU 301 controls the operation of the main control unit 200 by executing the control program stored in the ROM 303 using the RAM 302 as a work area. A PDL (Page Description Language) control unit 304, an internal interface (I/F) unit 305, and an operation unit 306 are connected to the bus.

The PDL control unit 304 performs print data processing, storage, image processing, and the like. The internal I/F unit 305 is a communication interface for communicating with the printer control unit 201. The operation unit 306 transmits the user instruction received from the input device to the CPU 301. The operation unit 306 displays an image on the display according to an instruction from the CPU 301. When the operation unit 306 instructs printing (image formation), the CPU 301 of the main control unit 200 transmits the print data processed by the PDL control unit 304 to the printer control unit 201 via the internal I/F unit 305. To do.

The printer control unit 201 is an information processing device including a CPU 311, a RAM 312, and a ROM 313. The CPU 311, RAM 312, and ROM 313 are connected via a bus. The CPU 311 executes the control program stored in the ROM 313 by using the RAM 312 as a work area to execute the basic control of the operation for image formation. A device control unit 314 and an internal I/F unit 315 are connected to the bus. The CPU 311 receives an image signal including print data from the main control unit 200 and controls the device control unit 314 to control the image forming operation. The multi-feed detection sensor 30 and the conveyance detection sensors 31, 32 are connected to the device control unit 314. The internal I/F unit 315 is a communication interface for communicating with the main control unit 200. The printer control unit 201 detects the double feeding of sheets based on the detection result of the double feeding detection sensor 30. Further, the printer control unit 201 confirms the failure of the double feed detection sensor 30 based on the detection results of the double feed detection sensor 30 and the conveyance detection sensors 31 and 32.

(Double feed detection)
FIG. 3 is an explanatory diagram of the double feed detection sensor 30. The double feed detection sensor 30 detects the double feed of the sheets conveyed between the two guide plates 402a and 402b forming the conveyance path (horizontal path 40). The double feed detection sensor 30 of the present embodiment is an ultrasonic sensor and includes a transmission unit 401a and a reception unit 401b. The reception unit 401b is arranged to face the transmission unit 401a with the horizontal path 40 interposed therebetween.

The transmission unit 401a is connected to the device control unit 314 via, for example, a power amplification circuit (not shown). The device control unit 314 outputs a pulse signal having a predetermined frequency under the control of the CPU 311. The pulse signal is amplified by the power amplification circuit and input to the transmission unit 401a. The transmission unit 401a is driven by a pulse signal acquired from the power amplification circuit to transmit ultrasonic waves.

The reception unit 401b is connected to the device control unit 314 via, for example, an output amplifier circuit and a rectifying/smoothing circuit (not shown). The reception unit 401b outputs a detection signal having a level corresponding to the intensity of the received ultrasonic wave. The detection signal is amplified by the output amplification circuit, rectified by the rectification smoothing circuit, and input to the device control unit 314. The device control unit 314 acquires and transmits the detection signal to the CPU 311. The CPU 311 detects double feeding based on the detection signal. For example, when the intensity (reception level) of the received ultrasonic wave represented by the detection signal is equal to or less than the threshold for determining the double feeding, the CPU 311 determines that the sheets are double fed. The CPU 311 that has determined that the sheets are double-fed notifies the main controller 200 of the occurrence of double-fed via the internal I/F unit 315. When notified of the occurrence of the double feed, the CPU 301 of the main control unit 200 notifies the user of the occurrence of the double feed by the operation unit 306. Such a double feed detection process is repeatedly performed during the image forming process.

FIG. 4 is a flowchart showing a process of detecting a failure of the double feed detection sensor 30. FIG. 5 is an explanatory diagram of failure detection of the double feed detection sensor 30. The failure detection process of the double feed detection sensor 30 is performed prior to the double feed detection process.

The CPU 311 measures the reception level of the double feed detection sensor 30 before starting the sheet conveyance (S701). To this end, the CPU 311 causes the device control unit 314 to transmit ultrasonic waves from the transmission unit 401a of the double feed detection sensor 30. The CPU 311 acquires the detection result (detection signal) of the ultrasonic wave received by the reception unit 401b via the device control unit 314. The CPU 311 measures the reception level by the detection signal.

The CPU 311 compares the measured reception level with an abnormality determination threshold value for determining an abnormality of the double feed detection sensor 30 (S702). The abnormality determination threshold is set to a value larger than the threshold for determining double feeding because it is necessary to detect even a single feeding in which only one sheet is conveyed. For example, assuming that the intensity of the ultrasonic wave transmitted from the transmission unit 401a is 100%, the abnormality determination threshold value is set to 40%.

When the reception level is higher than the abnormality determination threshold value (S702: N), the CPU 311 determines that the double feed detection sensor 30 is operating normally (S703). FIG. 5A shows a state in which the double feed detection sensor 30 is operating normally. Since there is no residue between the transmitting unit 401a and the receiving unit 401b and the transmitting unit 401a and the receiving unit 401b are not broken, the ultrasonic wave 411a is almost 100% in the receiving unit 401b (no attenuation). Status).

When the reception level is equal to or lower than the abnormality determination threshold value (S702: Y), the CPU 311 confirms the state (detection result) of the transport detection sensors 31 and 32 located in the vicinity of the upstream and the downstream of the double feed detection sensor 30 (S704). The CPU 311 determines whether or not the conveyance detection sensors 31 and 32 are in the on state (the state in which the signal indicating the presence of the sheet is output) (S705).

When the conveyance detection sensors 31 and 32 are in the off state (S705:N), the reception level of the double feed detection sensor 30 is abnormal when there is no residue at the detection position of the double feed detection sensor 30. In this case, the CPU 311 determines that an abnormality has occurred in the double feed detection sensor 30 (S706). FIG. 5C and FIG. 5D show a state in which an abnormality has occurred in the double feed detection sensor 30.
FIG. 5C shows a case where the transmission unit 401a operates normally and there is no residue between the transmission unit 401a and the reception unit 401b, and the reception unit 401b is out of order. The reception unit 401b is in a state where it cannot normally receive the ultrasonic wave 411a because of a failure. In this case, the intensity (reception level) of the ultrasonic wave 411a received by the receiving unit 401b is, for example, 0% regardless of the intensity of the ultrasonic wave that actually reaches the receiving unit 401b.
FIG. 5D shows a case where the receiving unit 401b is operating normally and there is no residue between the transmitting unit 401a and the receiving unit 401b, and the transmitting unit 401a is out of order. In this case, the intensity (reception level) of the ultrasonic wave received by the receiving unit 401a is, for example, 0% because the transmitting unit 401a is not normally transmitting the ultrasonic wave 411a.

The CPU 311 that has determined that an abnormality has occurred in the double feed detection sensor 30 notifies the user of the abnormality of the double feed detection sensor 30 (S713). The CPU 311 transmits an instruction via the internal I/F unit 315 to the main control unit 200 to notify the abnormality of the double feed detection sensor 30. In response to this instruction, the CPU 301 of the main control unit 200 uses the operation unit 306 to notify the abnormality of the double feed detection sensor 30. This allows the user to take measures such as replacement of the double feed detection sensor 30.

When the conveyance detection sensors 31 and 32 are in the ON state (S705:Y), the reception level of the multi-feed detection sensor 30 is abnormal when there is a residue at the detection position of the multi-feed detection sensor 30. In this case, the CPU 311 determines whether or not the number of times each of the conveyance detection sensors 31 and 32 has output a signal indicating the presence of a sheet exceeds a specified value (S707). Therefore, the CPU 311 counts the number of times the conveyance detection sensors 31 and 32 output a signal indicating the presence of a sheet. The specified value is, for example, 3 times. The number of times the conveyance detection sensors 31 and 32 output a signal indicating that a sheet is present in the state where the double feed detection sensor 30 is determined to be abnormal is the number of sheet detections. Does not include detection of the presence of a sheet during document transportation.

When the number of times of outputting the signal indicating the presence of the sheet exceeds the specified value (S707: Y), the CPU 311 turns on even though there is no residue because the conveyance detection sensor 31 or the conveyance detection sensor 32 has failed. Judge that it has become. Therefore, the CPU 311 determines that an abnormality may occur in the transport detection sensor 31 or the transport detection sensor 32 (S708).

The CPU 311 that has determined that there is a possibility that the conveyance detection sensor 31 or the conveyance detection sensor 32 has an abnormality indicates that the user may have an abnormality in the conveyance detection sensor 31 or the conveyance detection sensor 32. Notify (S713). The CPU 311 transmits an instruction to the main control unit 200 via the internal I/F unit 315 so as to notify that the conveyance detection sensor 31 or the conveyance detection sensor 32 may have an abnormality. In response to this instruction, the CPU 301 of the main control unit 200 notifies that there is a possibility that an abnormality has occurred in the transport detection sensor 31 or the transport detection sensor 32 using the operation unit 306. This allows the user to take measures such as replacement of the transport detection sensors 31 and 32.

When the number of times of outputting the signal indicating the presence of the sheet does not exceed the specified value (S707:N), the CPU 311 determines that there is a residue at the detection position of the double feed detection sensor 30 (S709). FIG. 5B shows a state in which the residue 412 is present at the detection position of the double feed detection sensor 30. Although the transmission unit 401a and the reception unit 401b have not failed, there is a residue 412 at the detection position between them. The residue 412 in this case also includes a sheet. When the ultrasonic wave 411a having the intensity of 100% is transmitted from the transmitting unit 401a, the ultrasonic wave 411a is attenuated by the residue 412 until the intensity is equal to or lower than the abnormality determination threshold (for example, 30%) (ultrasonic wave 411b). Therefore, the intensity (reception level) of the ultrasonic wave 411b received by the reception unit 401b becomes less than or equal to the abnormality determination threshold value (30%).

The CPU 311 increments the number of times of outputting the signal indicating the presence of the sheet by 1 (S710). The CPU 311 notifies the user to remove the residue on the transport path (horizontal path 40) (S711). The CPU 311 transmits an instruction to the main control unit 200 via the internal I/F unit 315 so as to notify the main control unit 200 of the residual substance removal. In response to this instruction, the CPU 301 of the main control unit 200 uses the operation unit 306 to notify the removal of the residue. The notification is performed by sound or image. FIG. 6 is a view showing an example of the notification screen. The notification screen 800 is displayed on the display of the operation unit 306. The notification screen 800 is displayed in the text field 801 as "Please remove the residue on the transport path." The button 802 is displayed as “removal of residue left”, and the user can tell the image forming apparatus 101 that the residue has been removed by pressing the button after removing the residue. Further, the CPU 301 of the main control unit 200 may use the speaker of the operation unit 306 to notify the user of residual substance removal by a residual substance removal voice or a warning sound.

The CPU 311 determines whether or not the user has removed the residue after notifying the removal of the residue (S712). When the notification is made on the notification screen of FIG. 6, the CPU 311 makes this determination depending on whether or not the button 802 is pressed. The CPU 311 continues to notify the removal of the residue until the residue is removed (S712:N). When the residue is removed (S712:), the CPU 311 performs the failure detection process of the double feed detection sensor 30 after S701 again.

It should be noted that the removal of the residue can be determined by the following processing, for example. For example, the CPU 311 causes the main control unit 200 to display a screen indicating occurrence of a jam on the display of the operation unit 306. The CPU 311 automatically determines whether or not the user has removed the residue based on the detection results of the transport detection sensors 31 and 32.

Through the above-described processing, the image forming apparatus 101 can accurately determine the cause when the intensity (reception level) of the ultrasonic wave received by the reception unit 401b is equal to or lower than the abnormality determination threshold. Specifically, the cause of the image forming apparatus 101 is a failure of the double feed detection sensor 30, a residue at the detection position of the double feed detection sensor 30, or an abnormality of the conveyance detection sensors 31 and 32. You can judge exactly how.

Claims (9)

An image forming unit that forms an image on a sheet conveyed through a conveyance path,
A multi-feed detection unit for detecting a state in which a plurality of sheets conveyed on the conveyance path are conveyed in an overlapping manner,
A conveyance detection unit for detecting the presence or absence of a sheet on the conveyance path,
Before starting the conveyance of the sheet, it judges the abnormality of the detection result of the multi-feed detection means, and when the detection result is abnormal, based on the detection result of the conveyance detection means, the cause of the abnormality is A determination unit that determines whether the double-feed detection unit is abnormal, the transfer path remains, or the transfer detection unit is abnormal.
Image forming apparatus. The double-feed detection means includes a transmission means for transmitting an ultrasonic wave and a reception means for receiving the ultrasonic wave transmitted from the transmission means, and a reception level of a reception level according to the intensity of the ultrasonic wave received by the reception means. The detection signal is output as the detection result,
The determination means may determine an abnormality in a detection result of the double feed detection means by comparing the detection signal with a predetermined abnormality determination threshold value.
The image forming apparatus according to claim 1. When the detection result of the double feed detection unit is abnormal, the determination unit determines that the double feed detection unit is abnormal unless the conveyance detection unit outputs a signal indicating that a sheet exists. Characteristic,
The image forming apparatus according to claim 1. When the determination unit determines that the double feed detection unit is abnormal, a predetermined notification unit notifies the abnormality of the double feed detection unit,
The image forming apparatus according to claim 3. The determination unit counts the number of times the conveyance detection unit outputs a signal indicating that a sheet is present when the detection result of the double-feed detection unit is abnormal, and the number of times the conveyance detection unit detects the sheet is predetermined. When it exceeds the specified value of, it is determined that there is a possibility of abnormality in the conveyance detection means,
The image forming apparatus according to claim 1. When the determination unit determines that there is a possibility of abnormality in the conveyance detection unit, a predetermined notification unit notifies the conveyance detection unit that there is a possibility of abnormality,
The image forming apparatus according to claim 5. When the detection result of the double feed detection unit is abnormal and the number of times the conveyance detection unit outputs a signal indicating the presence of a sheet does not exceed a predetermined specified value, the determination unit determines the double feed detection unit. It is determined that the abnormality of the detection result of is the residue of the transport path,
The image forming apparatus according to claim 5. When the determination unit determines that the abnormality in the detection result of the double-feed detection unit is the residue of the transport path, a predetermined notification unit notifies the removal of the residue,
The image forming apparatus according to claim 7. When the residue is removed, the determination means determines again the abnormality of the detection result of the double feed detection means,
The image forming apparatus according to claim 8.

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