JP2019090854A - Image forming apparatus and method for diagnosing abnormality in position detection function - Google Patents

Abstract

To solve the problem in which: there is a demand to specify a place of abnormality in a moving mechanism moving between two positions with a configuration simpler than the prior art.SOLUTION: In one embodiment of the present invention, the logic representing that a cleaning member 60 is present respectively at a first position and a second position, the logic representing that a first connector 72, a second connector 73, and a connector 74 for maintenance respectively come out, and the logic representing that a first sensor 62 and a second sensor 63 are respectively in an abnormal state, are identically set to "H." Embodiments obtain detection signals (detection logics) from the sensors, and detect coming-out of the connectors and abnormality in (dirt on) a motor 61 and the sensors from a change in the logics detected by the sensors while the motor is in operation.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus and an abnormality diagnosis method for a position detection function.

  A connector relaying a control board and a movement drive unit in a drive system having two or more position detection sensors and determining the position of the movement member by sensor detection logic and controlling the rotation direction of the motor for moving the movement member The following problems occur when the moving member starts to move with the sensor detection circuit in an abnormal state, or in a state in which the detection surface of the position detection sensor is contaminated and an abnormality occurs. First, since the stop position of the moving member can not be detected, the moving member may overrun and damage the moving drive unit including the moving member. Second, when the defective part of the position detection function can not be identified, it takes time to repair.

  On the other hand, when it is necessary to disconnect the connector to perform maintenance on the mobile drive unit, disconnect the connector while the power is off, and forget to insert the mobile drive unit in the connector even if the mobile drive unit is set at a predetermined position after maintenance. And it will be falsely detected as abnormal. For this reason, it is necessary to detect connector disconnection.

  According to Patent Document 1, in the charge wire cleaning device for detecting the position by the home position sensor (one) and the motor lock signal, when the motor lock signal is generated when the cleaning member is on the home position side, the home position sensor It is described that it is detected that the home position is surely if the switch is ON. Moreover, in patent document 1, the cleaning member for cleaning the charge wire 2 checks the signal from a home position sensor, and the detection signal is on, after the time which the home position sensor is reliably turned off passes. There is described a technique for determining that the home position sensor is abnormal if it remains as it is.

  In Patent Document 2, by connecting the LED power supply and signal line of the sensor to both ends of the connector and connecting the temperature sensor to the center of the connector, in the case of semi-insertion of the connector, the disconnection detection level of the sensor signal is detected. There is disclosed a technique for determining whether the disconnection of the sensor or the failure of the thermistor.

JP 06-214450 A JP 2004-219468 A

  In a drive system having two or more position detection sensors from the above situation and controlling the drive of a drive source (such as a motor) for moving the moving member by determining the position of the moving member by sensor detection logic It has been desired to identify abnormal points with a simpler configuration. Patent Literatures 1 and 2 do not consider the point of identifying such an abnormal part of the moving mechanism that moves two positions.

An image forming apparatus according to one aspect of the present invention is a movement that moves a moving member based on a moving member that moves between a first position and a second position, and a command input via a movement drive connector. A driving unit, a first position detection sensor provided at a first position and supplied with power via the first connector, and outputting a detection signal according to the position of the moving member via the first connector; A second position detection sensor which is provided at the position of the second power source, is supplied with power via the second connector, and outputs a detection signal according to the position of the movable member via the second connector; And a control unit that determines the position of the moving member using a detection signal output from the position detection sensor, and controls the operation of the movement drive unit.
In each of the first position detection sensor and the second position detection sensor, logic representing that there is a moving member in each of the first position and the second position, and disconnection of each of the first connector and the second connector The logic representing the same and the logic representing that each of the first position detection sensor and the second position detection sensor is in an abnormal state are the same. Then, the control unit performs at least an abnormality of the movement driving unit from detection signals of the first position detection sensor and the second position detection sensor before the movement start of the moving member and after the movement start as failure diagnosis of the position detection function. A process is performed to determine whether an abnormality of the position detection sensor or the second position detection sensor or the disconnection of the first connector or the second connector has occurred.

According to at least one aspect of the present invention, it is possible to identify an abnormal point of a moving mechanism that moves two positions with a configuration simpler than the prior art.
Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

FIG. 1 is a schematic cross-sectional view showing a configuration example of an image forming apparatus on which a position detection function according to a first embodiment of the present invention is mounted. It is an explanatory view showing an example of an electrode cleaning unit concerning a 1st embodiment of the present invention. It is a block diagram showing an example of composition of a position detection function concerning a 1st embodiment of the present invention. It is a table which shows the example of a setup of the sensor logic of the 1st sensor concerning the 1st embodiment of the present invention, and the 2nd sensor. It is explanatory drawing which shows the sensor logic of the 1st sensor in the normal stop position (1st position) which concerns on the 1st Embodiment of this invention, and a 2nd sensor. It is an explanatory view about operation specifications in case a cleaning member concerning a 1st embodiment of the present invention moves from a 1st position to a 2nd position. It is an explanatory view about an operation specification in case a cleaning member concerning a 1st embodiment of the present invention moves from a 2nd position to a 1st position. It is an explanatory view showing an example of detection of a connector for maintenance omission concerning a 1st embodiment of the present invention. It is an explanatory view showing the example of detection of the 1st connector omission concerning the 1st example of a 2nd embodiment of the present invention, and the 1st sensor abnormalities. It is explanatory drawing which shows the sensor logic in the example of a detection of the 1st connector omission and 1st sensor abnormality of FIG. It is an explanatory view showing the example of detection of the 2nd connector omission and the 2nd sensor abnormalities concerning the 2nd example of a 2nd embodiment of the present invention. It is explanatory drawing which shows the sensor logic in the example of a detection of the 2nd connector omission and 2nd sensor abnormality of FIG. It is an explanatory view showing an example of detection of motor connector omission and motor abnormalities concerning the 1st example of a 3rd embodiment of the present invention. It is an explanatory view showing an example of detection of motor connector omission and motor abnormalities concerning the 2nd example of a 3rd embodiment of the present invention. It is explanatory drawing which shows the example of a detection of the sensor detection circuit abnormality which concerns on the 4th Embodiment of this invention. It is explanatory drawing which shows the sensor logic in the example of a detection of the sensor detection circuit abnormality of FIG. It is explanatory drawing of sensor logic which shows the example of a detection of the connector for maintenance drop which concerns on the 1st example of the 5th Embodiment of this invention. It is explanatory drawing of sensor logic which shows the example of detection of 2nd sensor abnormality which concerns on the 2nd example of the 5th Embodiment of this invention. It is explanatory drawing of sensor logic which shows the example of detection of the 1st sensor abnormality which concerns on the 3rd example of the 5th Embodiment of this invention. It is explanatory drawing of sensor logic which shows the example of a detection of the connector omission (2nd connector detachment) of the 2nd sensor concerning the 4th example of a 5th embodiment of the present invention or the 2nd sensor abnormality. It is explanatory drawing of sensor logic which shows the example of detection of the motor abnormality which concerns on the 5th example of the 5th Embodiment of this invention. It is explanatory drawing of sensor logic which shows the example of a detection of motor connector disconnection or motor abnormality which concerns on the 6th example of 5th Embodiment of this invention. It is an explanatory view showing an example of composition of a motor current detection function of a control board concerning a 6th embodiment of the present invention. It is an explanatory view showing an example of a motor current waveform concerning the 1st example of a 6th embodiment of the present invention. It is an explanatory view showing an example of a motor current waveform concerning the 2nd example of a 6th embodiment of the present invention. It is an explanatory view showing an example of a motor current waveform concerning the 3rd example of a 6th embodiment of the present invention. It is flowchart (1) which shows the example of a procedure of the abnormal location identification process in the position detection function which concerns on the 7th Embodiment of this invention. It is a flowchart (2) which shows the example of a procedure of the abnormal location identification process in the position detection function which concerns on the 7th Embodiment of this invention. It is a flowchart (3) which shows the example of a procedure of the abnormal location identification process in the position detection function which concerns on the 7th Embodiment of this invention. It is a flowchart (4) which shows the example of a procedure of the abnormal location identification process in the position detection function which concerns on the 7th Embodiment of this invention.

  Hereinafter, examples of modes for carrying out the present invention (hereinafter, referred to as “embodiments”) will be described with reference to the attached drawings. The components having substantially the same function or configuration in the present specification and the attached drawings will be denoted by the same reference numerals and redundant description will be omitted.

<1. First embodiment>
[Configuration of image forming apparatus]
FIG. 1 is a schematic cross-sectional view showing a configuration example of an image forming apparatus on which the position detection function according to the first embodiment is mounted.
The image forming apparatus 1 shown in FIG. 1 adopts an electrophotographic method in which an image is formed using static electricity. For example, four of yellow (Y), magenta (M), cyan (C) and black (K) are used. This is a tandem-type color image forming apparatus in which toner images of colors (basic colors) are superimposed. The image forming apparatus 1 includes an image input unit 11 including sheet feed trays 20A and 20B, an image forming unit 30, an automatic document feeder (ADF) 12, and an operation display unit 13. The sheet feeding trays 20A and 20B can feed long sheets longer in the sheet conveyance direction than ordinary sheets, in addition to sheets of general size.

  Further, the image forming apparatus 1 is provided with a conveyance path 21 for conveying the sheet S fed from the sheet feed trays 20A and 20B or the manual feed tray. The conveyance path 21 is provided with a plurality of rollers (a conveyance roller, a registration roller, and the like) for conveying the sheet S. For example, on the upstream side of the secondary transfer portion 35 on the conveyance path 21, a registration roller 24 configured to be capable of pressure contact and separation for correcting the posture of the conveyed sheet is provided.

  The image forming unit 30 includes four image forming units 31Y, 31M, 31C, and 31K in order to form toner images of yellow, magenta, cyan, and black. The image forming units 31Y, 31M, 31C, and 31K may be collectively referred to as an image forming unit 31. Each image forming unit 31 includes a charging unit 33, an LED writing unit (laser light source), a developing unit, and a photosensitive drum. The image forming unit 30 further includes an intermediate transfer belt 34, a secondary transfer unit 35, and the like on which the images formed on the photosensitive drums 32Y, 32M, 32C and 32K of the image forming units 31Y, 31M, 31C and 31K are transferred. A fixing unit 36 is provided downstream of the secondary transfer unit 35 in the sheet conveyance direction. The photosensitive drums 32Y, 32M, 32C, and 32K may be collectively referred to as a photosensitive drum 32.

  On the downstream side of the fixing unit 36 in the sheet conveyance direction, the conveyance path 21 is extended and connected to the sheet discharge outlet. Further, a reverse conveyance path 23 which branches on the downstream side of the fixing unit 36 and joins the conveyance path 21 on the upstream side of the secondary transfer unit 35 is connected to the conveyance path 21. The reversing conveyance path 23 is provided with a reversing unit 22 that reverses the sheet S. The reversing unit 22 reverses the sheet S conveyed from the fixing unit 36, and conveys the sheet S to the conveyance path 21 on the upstream side of the secondary transfer unit 35 through the inversion conveyance path 23. Further, the reversing unit 22 can return the reversed sheet S to the conveyance path 21 on the downstream side of the fixing unit 36 and discharge it as it is.

  An operation display unit 13 is installed on the top of the image forming apparatus 1. The operation display unit 13 has a function as an operation unit for instructing start of a job such as an image forming process, for example. The operation display unit 13 is provided with a display unit (not shown) formed of a liquid crystal panel or the like and an operation unit (not shown) formed of a touch panel or the like. The display unit can display the user's operation contents and setting information. The operation display unit 13 may be configured by a mouse, a tablet, or the like, and may be configured separately from the display unit.

  In the image forming mode, the image forming apparatus 1 charges the photosensitive drum 32 included in the image forming unit 31 of each color and exposes the surface of the photosensitive drum 32 in accordance with the document image, and electrostatic latent image is formed on the photosensitive drum 32. Form an image. Then, toner is attached to the electrostatic latent image of the photosensitive drum 32 corresponding to each of yellow, magenta, cyan and black by using a developing unit, and a toner image of each color is formed. Next, the toner images formed on the yellow, magenta, cyan, and black photosensitive drums 32 are sequentially primarily transferred onto the surface of the intermediate transfer belt 34 that is rotationally driven.

  Next, the toner images of the respective colors primarily transferred onto the intermediate transfer belt 34 are secondarily transferred onto the sheet S transported on the transport path 21 by the secondary transfer portion 35 (secondary transfer roller). The secondary transfer of the toner images of the respective colors on the intermediate transfer belt 34 onto the sheet S forms a color image. The image forming apparatus 1 discharges the sheet S on which the color toner image is formed to the fixing unit 36. A cleaning member 37 for scraping and removing the toner remaining on the intermediate transfer belt 34 is provided on the downstream side of the secondary transfer portion 35 on the intermediate transfer belt 34. The cleaning member 37 is configured to be movable at a position abutted against the surface of the intermediate transfer belt 34 and a position not abutted.

  The fixing unit 36 is an apparatus for performing a fixing process on the sheet S supplied from the image forming apparatus 1 on which a color toner image is formed. The fixing unit 36 fixes the transferred toner image on the sheet S by pressing and heating the conveyed sheet S. The fixing unit 36 includes, for example, an upper fixing roller and a lower fixing roller, which are fixing members. The upper fixing roller and the lower fixing roller are disposed in pressure contact with each other, and a fixing nip portion is formed as a pressure contact portion between the upper fixing roller and the lower fixing roller.

  A heating unit is provided inside the fixing upper roller. The radiant heat from the heating portion heats the roller portion at the outer peripheral portion of the fixing upper roller. The sheet S is conveyed to the fixing nip portion so that the surface (the fixing target surface) on which the toner image is transferred by the secondary transfer portion 35 faces the fixing upper roller. The sheet S passing through the fixing nip portion is pressurized by the upper fixing roller and the lower fixing roller and heated by the heat of the roller portion of the upper fixing roller. The sheet S on which the fixing process has been performed by the fixing unit 36 is discharged from the sheet discharge tray 40.

  The position detection function of this embodiment includes the positions of moving members that move at least two positions, such as the registration roller 24, the cleaning member 37, and the cleaning member 60 (see FIG. 2) that cleans the charging wire 33w of the charging unit 33. Detect Hereinafter, the position detection function of the present embodiment will be described by taking, as an example, the case of detecting the position of the cleaning member 60 reciprocating as the moving member.

[Electrode Cleaning Unit]
FIG. 2 is an explanatory view showing an example of the electrode cleaning unit 33c for cleaning the charging wire 33w of the charging unit 33. As shown in FIG.
The electrode cleaning unit 33c includes a cleaning member 60, a feed screw 60a, a first position detection sensor (hereinafter referred to as "first sensor") 62, and a second position detection sensor (hereinafter referred to as "second sensor") 63, And a motor 61 (an example of a movement drive unit).

The cleaning member 60 abuts on a rod-like charging wire 33w that charges the surface of the photosensitive drum, and neutralizes the charge on the charging wire 33w.
The feed screw 60a is a transfer body which is screwed into the cleaning member 60 and disposed substantially in parallel with the charging wire 33w, and moves the cleaning member 60 in substantially parallel with the charging wire 33w. The driven gear 60b is fixed to the end of the feed screw 60a, and the driven gear 60c rotationally driven by the motor 61 meshes with the driven gear 60b, whereby the driven gear 60b is rotated. Depending on the rotation direction of the motor 61, the cleaning member 60 moves in the F direction (the direction from the first position to the second position) or in the R direction (the direction from the second position to the first position).

  The first sensor 62 is disposed at a position (example of a first position) corresponding to one end of the feed screw 60a. The first sensor 62 has a movable segment 62a, and when the movable segment 62a is pressed directly or indirectly by the first sensor 62, an actuator configured of the movable segment 62a and the movable mechanism is turned on. At this time, the first sensor 62 outputs a High signal (hereinafter abbreviated as “H signal”) as a detection signal. In addition, when the actuator is in the OFF state, the first sensor 62 outputs a Low signal (hereinafter abbreviated as “L signal”) as a detection signal.

  Similarly, the second sensor 63 is disposed at a position (example of a second position) corresponding to the other end of the feed screw 60a. The second sensor 63 has a movable segment 63a, and when the movable segment 63a is pressed directly or indirectly by the second sensor 63, an actuator configured of the movable segment 63a and the movable mechanism is turned on. At this time, the second sensor 63 outputs an H signal as a detection signal. When the actuator is in the OFF state, the second sensor 63 outputs an L signal as a detection signal. In the present embodiment and each embodiment to be described later, as shown in FIG. 2, an intermediate position is defined between the first position and the second position.

  In the present specification, each of the first sensor 62 and the second sensor 63 outputs an H signal as a detection signal, or the state of each sensor is referred to as "the sensor logic is H", and as a detection signal. Outputting the L signal or its state of each sensor is referred to as "sensor logic is L".

  The motor 61 is connected to the motor connector 71 by wiring. The motor connector 71, the first connector 72 to which the first sensor 62 is connected, and the second connector 73 to which the second sensor 63 is connected are respectively connected to the male connector 74b of the maintenance connector 74. . The maintenance connector 74 is composed of a male connector 74b and a female connector 74a, and the female connector 74a is connected to the control board 50 (see FIG. 3) through a wire.

[Control board]
FIG. 3 is a block diagram showing a configuration example of the control board 50 for realizing the position detection function.
A maintenance connector 74 is connected to the control board 50 shown in FIG. The control board 50 includes a control unit 51, a non-volatile memory 52, a driver (drive circuit) 53, a current detection unit 54, a first power supply unit 55, and a second power supply unit 56.

  The control unit 51 controls each part of the control board 50 and performs various arithmetic processing. The control unit 51 is configured of, for example, a CPU (Central Processing Unit). The CPU executes the control program stored in the non-volatile memory 52 to implement each function in the present embodiment. Furthermore, the control unit 51 performs arithmetic processing and control based on the operation signal input from the operation display unit 13.

  The control unit 51 sends a control signal (CONT signal) to the first power supply unit 55 to control the operation of the first power supply unit 55. The control unit 51 also sends a control signal (CONT signal) to the second power supply unit 56 to control the operation of the second power supply unit 56.

  The first power supply unit 55 supplies power to the first sensor 62 via the maintenance connector 74 and the first connector 72 based on the control signal, and via the maintenance connector 74 and the second connector 73. Power is supplied to the second sensor 63.

  The second power supply unit 56 is grounded through the sensor detection circuit 50d. The sensor detection circuit 50d includes two series circuits in which a resistor R1 and a resistor R2 are connected in series. That is, the sensor detection circuit 50d is provided for each of the first sensor 62 and the second sensor 63. A connection point between the resistor R1 and the resistor R2 of the first series circuit is connected to the first sensor 62 via the first connector 72 and the maintenance connector 74, and a detection signal of the first sensor 62 (first sensor The detection signal is taken into the control unit 51 through the connection point of the resistors R1 and R2. In addition, the connection point between the resistor R1 and the resistor R2 of the second series circuit is connected to the second sensor 63 via the second connector 73 and the maintenance connector 74, and the detection signal of the second sensor 63 2 sensor detection signal) The control unit 51 is taken in through the connection point of the resistor R1 and the resistor R2. The sensor detection circuit 50d will be described in detail with reference to FIG. 15 described later.

  The control unit 51 also outputs control signals (CONT, F / R) to the driver 53. The driver 53 supplies a drive signal to the motor 61 through the maintenance connector 74 and the motor connector 71 based on the control signal from the control unit 51. The motor 61 is rotationally driven in a designated direction and speed based on the drive signal. The driver 53 also supplies the motor current output from the motor 61 to the current detection unit 54. The current detection unit 54 detects the motor current supplied from the driver 53, and outputs information on the detected motor current to the control unit 51.

  As shown in FIGS. 2 and 3, the first sensor 62 outputs a detection signal corresponding to the position of the cleaning member 60 to the control unit 51 via the first connector 72 and the maintenance connector 74. In addition, the second sensor 63 outputs a detection signal corresponding to the position of the cleaning member 60 to the control unit 51 via the second connector 73 and the maintenance connector 74.

[Sensor logic]
FIG. 4 is a table showing a setting example of sensor logic of the first sensor 62 and the second sensor 63. A table defining sensor logic as shown in FIG. 4 is stored in advance in the non-volatile memory 52 so that the control unit 51 can refer to it.

  When the cleaning member 60 is in the middle position, the logic of the first sensor 62 is "L (not in the first position)" and the logic of the second sensor 63 is "L (not in the second position)" is there. Also, when the cleaning member 60 is in the first position, the logic of the first sensor 62 is "H (present in the first position)", and the logic of the second sensor 63 is "L (not in the second position ). When the cleaning member 60 is in the second position, the logic of the first sensor 62 is "L (not in the first position)", and the logic of the second sensor 63 is "H (in the second position ). Furthermore, in the case of the maintenance connector disconnection, the logic of the first sensor 62 is "H", and the logic of the second sensor 63 is also "H".

  As shown in FIG. 15 described later, when the first connector 72, the second connector 73, or the maintenance connector is removed in order to pull up the detection signal in the sensor detection circuit 50d corresponding to each sensor, The logic of each of the first sensor 62 and the second sensor 63 is "H". Also, as shown in FIG. 16 described later, when the detection surface of each sensor is dirty and is in a sensor abnormality state, the detection signal of each sensor is “H”.

  As described above, in the present embodiment and each embodiment to be described later, a logic indicating that the cleaning member 60 exists in each of the first position and the second position, the first connector 72, the second connector 73, and the maintenance The logic representing disconnection of each of the connectors 73 and the logic representing an abnormal state of each of the first sensor 62 and the second sensor 63 are set to the same "H". And each embodiment obtains the detection signal (detection logic) of each sensor, and detects a connector omission, abnormality (dirt) of a motor or a sensor, etc. from change of detection logic of each sensor at the time of motor 61 operation. be able to.

  For example, as described later, according to each embodiment, from the detection signals of the first sensor 62 and the second sensor 63 before the start of movement of the cleaning member 60 and after the start of movement, the abnormality of the motor 61, the first sensor 62 or the second It is possible to determine which one of the abnormality of the sensor 63 and the disconnection of the first connector 72 or the second connector 73 has occurred.

[Sensor logic of normal stop position]
FIG. 5 is an explanatory view showing sensor logic of the first sensor 62 and the second sensor 63 at the normal stop position (first position).
When the position detection function is normal, when the cleaning member 60 stops at the first position, the actuator is ON and the first connector 72 does not come off, so the logic of the first sensor 62 is “H”. Also, the actuator is off, and the logic of the second sensor 63 becomes "L". When the sensor logic of each sensor is the above (FIG. 5), the control unit 51 determines that the operation member 60 is normally stopped at the first position, and issues a command to the motor 61 by the driver 53, The movement of the cleaning member 60 is started toward the second position.

  When the cleaning member 60 is in the second position, when the logic of the first sensor 62 is “L” and the logic of the second sensor 63 is “H”, the operation member 60 is in the second position. The movement of the cleaning member 60 is started toward the first position.

[Operation specification when moving from the first position to the second position]
FIG. 6 is an explanatory view of an operation specification when the cleaning member 60 moves from the first position to the second position.
Since the cleaning member 60 is in the first position, the logic of the first sensor 62 is “H” indicating that the cleaning member is present (upper part in FIG. 6). At the start of cleaning member movement, the control unit 51 confirms that the logic of the movement destination second sensor 63 is “L” indicating no cleaning member at the second position, and the cleaning member 60 is in the F direction ( The motor 61 is rotated forward (F rotation) so as to move from the first position to the second position).

  When the cleaning member 60 leaves the first position and becomes the intermediate position, the actuator of the first sensor 62 is turned off, and the logic of the first sensor 62 becomes "L indicating no cleaning member at the first position". (FIG. 6, middle row). Then, when the cleaning member 60 reaches the second position, the actuator of the second sensor 63 is turned on, and the logic of the second sensor 63 changes to “H” indicating that the cleaning member is present at the second position, The control unit 51 stops the motor 61 (FIG. 6, lower stage).

[Operation specification when moving from the second position to the first position]
FIG. 7 is an explanatory view of an operation specification when the cleaning member 60 moves from the second position to the first position.
Since the cleaning member 60 is in the second position, the logic of the second sensor 63 is “H” indicating that the cleaning member is present (upper part in FIG. 7). At the start of cleaning member movement, the control unit 51 confirms that the logic of the movement destination first sensor 62 is “L” indicating no cleaning member at the first position, and the cleaning member 60 is in the R direction ( The motor 61 is reversely rotated (R rotation) so as to move from the second position to the first position).

  When the cleaning member 60 leaves the second position and becomes the intermediate position, the actuator of the second sensor 63 is turned off, and the logic of the second sensor 63 becomes "L" (center in FIG. 7). When the cleaning member 60 reaches the first position, the actuator of the first sensor 62 is turned on, the logic of the first sensor 62 changes to "H", and the control unit 51 stops the motor 61 (FIG. 7). Bottom).

[Connector for maintenance removal]
FIG. 8 is an explanatory view showing an example of detection of the maintenance connector disconnection.
It is assumed that the male connector 74b and the female connector 74a of the maintenance connector 73 are separated from each other. Regardless of whether the cleaning member 60 is at the first position, the intermediate position, or the second position, the logic of both the first sensor 62 and the second sensor 63 is “H” indicating that the cleaning member is present. If there is, the control unit 51 determines that the maintenance connector is missing. Even when both the first connector 72 and the second connector 73 are disconnected, the logic of both the first sensor 62 and the second sensor 63 is “H”, so in this case, the first The disconnection of the connector 72 and the second connector 73 may be determined.

<2. Second embodiment>
The second embodiment is connected to the first sensor 62 (second sensor 63) when the cleaning member 60 is at the first position (second position) or the cleaning member 60 is at the middle position. It is an example which detects the drop-off of connector 72 (the 2nd connector 73), or the abnormalities of the 1st sensor 62 (the 2nd sensor 63).

[First example]
FIG. 9 is an explanatory view showing a detection example of the first connector 72 disconnection and the first sensor 62 abnormality according to the first example of the second embodiment. FIG. 10 shows sensor logic in an example of detection of the first connector 72 disconnection and the first sensor 62 abnormality shown in FIG.

  When the cleaning member 60 is in the first position, the actuator of the first sensor 62 is turned on, and the logic of the first sensor 62 is "H". Further, the actuator of the second sensor 63 is turned off, and the logic of the second sensor 63 is "L" (upper part of FIG. 9). Here, when the cleaning member 60 is moved to the second position, the cleaning member 60 leaves the first position and the actuator of the first sensor 62 is turned off, but the logic of the first sensor 62 is “H”. Suppose that it was as it was. The actuator of the movement destination second sensor 63 is OFF, and the logic of the second sensor 63 remains "L" (center in FIG. 9).

  When the logic of the second sensor 63 becomes "H" (the cleaning member is at the second position) while the logic of the first sensor 62 remains "H" (the lower part of FIG. 9), the logic of the second sensor 63 Is changed from the logic before movement, the motor 61 operates normally. Therefore, the control unit 51 determines that the connector of the first sensor 62 is missing or the first sensor 62 is abnormal.

[Second example]
FIG. 11 is an explanatory view showing a detection example of the second connector 73 disconnection and the second sensor 63 abnormality according to the second example of the second embodiment. FIG. 12 shows sensor logic in the detection example of the second connector 73 disconnection and the second sensor 63 abnormality of FIG.

  When the cleaning member 60 is in the second position, the actuator of the second sensor 63 is turned on, and the logic of the second sensor 63 is "H". Also, the actuator of the first sensor 62 is turned off, and the logic of the first sensor 62 is "L" (upper part of FIG. 11). Here, when the cleaning member 60 is moved to the first position, the cleaning member 60 leaves the second position and the actuator of the second sensor 63 is turned off, but the logic of the second sensor 63 is “H”. Suppose that it was as it was. The actuator of the destination first sensor 62 is OFF, and the logic of the first sensor 62 remains "L" (center in FIG. 11).

  When the logic of the first sensor 62 becomes "H" (the cleaning member is at the first position) while the logic of the second sensor 63 remains "H" (the lower part of FIG. 11), the logic of the first sensor 62 Is changed from the logic before movement, the motor 61 operates normally. Therefore, the control unit 51 determines that the connector of the second sensor 63 is missing or the second sensor 63 is abnormal.

<3. Third embodiment>
The third embodiment is an example in which removal of the motor connector 71 or abnormal operation of the motor 61 is detected.

[First example]
FIG. 13 is an explanatory view showing a detection example of motor connector 71 disconnection and motor 61 abnormality according to the first example of the third embodiment. Here, the case where the cleaning member 60 moves from the first position to the second position will be described as an example.

  In a state where the logic of the first sensor 62 is “H” and the logic of the second sensor 63 is “L”, the control unit 51 instructs the movement of the cleaning member 60 and then the second sensor 63 If the logic remains "L", the cleaning member 60 remains at the first position. Therefore, the control unit 51 determines that the motor connector 71 is removed or the operation of the motor 61 is abnormal.

[Second example]
FIG. 14 is an explanatory view showing a detection example of the motor connector 71 disconnection and the motor 61 abnormality according to the second example of the third embodiment. Here, the case where the cleaning member 60 moves from the second position to the first position will be described as an example.

  In a state where the logic of the second sensor 63 is “H” and the logic of the first sensor 62 is “L”, the control unit 51 instructs the movement of the cleaning member 60 and then the first sensor 62 If the logic remains "L", the cleaning member 60 remains in the second position. Therefore, the control unit 51 determines that the motor connector 71 is removed or the operation of the motor 61 is abnormal.

<4. Fourth embodiment>
The fourth embodiment is an example in which the operation check of the sensor detection circuit 50 d provided in the control board 50 is performed. That is, in the present embodiment, the control unit 51 determines whether the sensor detection circuit 50d is normal or abnormal.

FIG. 15 is an explanatory view showing a detection example of a sensor detection circuit abnormality according to the fourth embodiment.
Since the configuration of the sensor detection circuit 50d corresponding to each of the first sensor 62 and the second sensor 63 is the same, only the sensor detection circuit 50d corresponding to the first sensor 62 will be described.

  The sensor detection circuit 50d includes transistors 57-1 and 57-2 which are switching elements, and resistors R1 and R2. The emitter terminal of the transistor 57-1 is connected to the first power supply unit 55, and the collector terminal of the transistor 57-1 is connected to the light emitting unit 64 formed of a resistor and a diode of the first sensor 62. The sensor power supply signal (CONT signal in FIG. 3) is input from the control unit 51 to the base terminal of the transistor 57-1. As described above, the first power supply unit 55 supplies sensor power (first power) to each sensor via the sensor detection circuit 50 d provided corresponding to each of the first sensor 62 and the second sensor 63. Although bipolar transistors are used as the transistors 57-1 and 57-2, field effect transistors may be used.

  The emitter terminal of the transistor 57-2 is connected to the second power supply unit 56, and the collector terminal of the transistor 57-2 is grounded via a series circuit of a resistor R1 and a resistor R2. The connection point between the resistor R1 and the resistor R2 is connected to the light receiving unit 65 formed of the phototransistor of the first sensor 62 and to the control unit 51. The pull-up power supply signal (CONT signal in FIG. 3) is input from the control unit 51 to the base terminal of the transistor 57-2. The voltage applied to the resistor R2 is taken into the control unit 51 as a sensor detection signal. As described above, the second power supply unit 56 supplies pull-up power (second power supply) to each sensor via the sensor detection circuit 50 d provided corresponding to each of the first sensor 62 and the second sensor 63. In FIG. 15, the power supply voltages of the first power supply unit 55 and the second power supply unit 56 are 3.3 V, the resistance value of the resistor R1 is 2.2 kΩ, and the resistance value of the resistor R2 is 100 kΩ. It is not limited to this example.

  In the sensor detection circuit 50d configured as described above, by controlling the pull-up power supply and the sensor power supply with respect to the sensor detection signal, it is possible to determine whether the sensor detection circuit 50d is operating normally.

FIG. 16 shows sensor logic in the detection example of the sensor detection circuit abnormality of FIG.
The first condition is that the sensor detection signal is “H” (with a member when the shield 66 is inserted (shielded) between the light emitting unit 64 and the light receiving unit 65 and the sensor power supply and the pull-up power supply are supplied. ). Here, when the supply of the pull-up power supply is switched from ON to OFF, if the sensor detection signal changes from "H" to "L" (no member), the control sensor detection circuit 50d (control board 50) is normal. is there. However, when the sensor detection signal remains "H", the control unit 51 determines that the sensor detection circuit 50d (control board 50) is abnormal. The shield 66 reciprocates between a position where the light emitted from the light emitting unit 64 to the light receiving unit 65 is blocked and a position where the light is not blocked by a drive source (motor, cylinder or the like) and a moving mechanism (not shown). The movement of the shield 66 is performed based on an instruction of the control unit 51.

  The second condition is that the sensor detection signal is “L” (member in the state where the shield 66 does not exist (open) between the light emitting unit 64 and the light receiving unit 65 and the sensor power supply and the pull-up power supply are supplied. None). Here, when the sensor power supply is switched from ON to OFF, if the sensor detection signal changes from "L" to "H" (member present), the control sensor detection circuit 50d (control substrate 50) is normal. . However, if the sensor detection signal remains “L”, the control unit 51 determines that the ground fault of the wiring in the sensor detection circuit 50 d or the sensor detection circuit 50 d (control board 50) is abnormal.

  Since the sensor detection circuit 50d is provided for each sensor, the control unit 51 performs operation check on all the sensor detection circuits 50d.

  In the fourth embodiment described above, the power supply supplied to the first sensor 62 and the second sensor 63 and the power supply pulling up the detection signal of the sensor can be turned off / on. Then, when the detection signal detects the presence of the cleaning member, the power source pulling up is turned off, and it is confirmed whether the detection signal changes without the cleaning member. Also. If the detection signal detects no cleaning member, the power supplied to the sensor is turned off, and it is checked whether the detection signal changes to the presence of the cleaning member. By these checks, it can be determined whether the sensor detection circuit can normally detect the position of the cleaning member.

<5. Fifth embodiment>
In the fifth embodiment, the sensor logic at the time of completion of the operation of the moving member 60 and the abnormality detection result are stored, and the stored information is used for abnormality diagnosis.

[First example]
FIG. 17 is an explanatory diagram of sensor logic showing a detection example of the maintenance connector disconnection according to the first example of the fifth embodiment. In the first example, the moving operation of the cleaning member 60 is normally ended last time, and the first sensor 62 and the second sensor 63 both have normal stop positions at the time of the moving operation of the cleaning member 60 after power OFF and ON. This is an example of the case where it is detected that the cleaning member is present, and is an example of detection of disconnection of the maintenance connector 74. The control unit 51 accumulates the information of the detection example shown in FIG. 17 in a database (not shown) of the non-volatile memory 52. The power supply here is a main power supply or the like of the image forming apparatus 1, and for example, when the main power supply is turned off, the power supply of the control board 50 (control unit 51) is turned off.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Then, when the cleaning member 60 moves from the second position to the first position, which is the home position, one operation (cleaning process) ends. The sensor logic after the end of the operation is that the first sensor 62 is “H” and the second sensor 63 is “L”. Therefore, the control unit 51 determines that this operation has ended normally.

  Here, when the control board 50 is powered off, the sensor logic at power off (strictly speaking, immediately before power off) is “H” for the first sensor 62 and “L” for the second sensor 63. The control unit 51 stores information that the cleaning member 60 is at the first position in the database, and ends when the sensor logic of the previous operation is normal when the power is turned off.

  Next, when starting the operation this time, the control board 50 is powered on and turned on. When the cleaning member 60 is in the first position, the control unit 51 first causes both the first sensor 62 and the second sensor 63 after the power is turned on to be "H" indicating that there is a cleaning member (change to abnormal In the case of), it is determined that the maintenance connector 74 is disconnected, and a warning is displayed on the operation display unit 13. Then, the control unit 51 does not store the sensor logic immediately before the power-off in the database when the power is turned off after the current operation. The reason is that if the data of the previous operation is overwritten with the data of the current operation, the position of the cleaning member 60 and the state of each sensor can not be known. Therefore, in this case, since the data indicates that the cleaning member is present at the previous first position, the first sensor 62 is "H," and the second sensor 63 is "L."

[Second example]
FIG. 18 is an explanatory diagram of sensor logic showing an example of detecting a second sensor abnormality according to a second example of the fifth embodiment. In the second example, the moving operation of the cleaning member 60 is normally completed last time, there is no power OFF and ON, and both the first sensor 62 and the second sensor 63 have the cleaning member 60 at the moving operation of the cleaning member 60 this time. Is an example of the case of detecting.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Thereafter, when the cleaning member 60 moves from the second position to the first position, one operation (cleaning process) ends. The sensor logic after the end of the operation is that the first sensor 62 is “H” and the second sensor 63 is “L”. Therefore, the control unit 51 determines that this operation has ended normally.

  Next, at the start of the operation this time, the cleaning member 60 is in the first position, but the second sensor 63 changes from “L” to “H” (abnormal), and the first sensor 62 and the second sensor When both 63 become “H”, the control unit 51 determines that the second sensor 63 is abnormal, and displays a warning on the operation display unit 13. Then, the control unit 51 stores, in the database, the sensor logic immediately before the power-off after the current operation and the abnormality information data (the abnormality of the second sensor 63).

[Third example]
FIG. 19 is an explanatory diagram of sensor logic showing an example of detecting a first sensor abnormality according to a third example of the fifth embodiment. In the third example, the cleaning member 60 moved to the second position last time, but the first sensor 63 detects that the first sensor is abnormal without detecting the absence of the cleaning member, and then the power is turned on and off. When there is no change in the sensor logic at the time of the movement operation of the cleaning member 60 this time, it is an example of a case where it is not detected that the maintenance connector 74 has been disconnected but detected as an abnormality of the first sensor 62 similar to the previous time.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Thereafter, although the cleaning member 60 abnormally ends at the second position, the first sensor 62 remains “H” (abnormal), so the control unit 51 determines that the first sensor 72 is abnormal, The warning is displayed on the operation display unit 13 and the abnormality information data is stored in the database.

  Here, when the power of the control board 50 is turned off, the sensor logic when the power is turned off (strictly, immediately before the power is turned off) is that the first sensor 62 is "H" (abnormal) and the second sensor 63 is "H". It is. The control unit 51 also stores the sensor logic immediately before the power-off in the database.

  Next, when starting the operation this time, the control board 50 is powered on and turned on. Here, it is assumed that the cleaning member 60 has moved to the first position, which is the home position. The sensor logic at the start of movement at this time is that the first sensor 62 is “H” (abnormal), the second sensor 63 is also “L”, and no change is seen in the sensor logic as it is at the previous abnormality. Therefore, the control unit 51 determines that the first sensor 62 is abnormal and does not move the cleaning member 60. Then, the control unit 51 stores, in the database, the sensor logic immediately before OFF at the time of power OFF after the current operation and the same abnormality information data (abnormality of the first sensor 62) as in the previous time.

[4th example]
FIG. 20 is an explanatory diagram of sensor logic showing an example of detection of connector disconnection (second connector disconnection) of the second sensor or second sensor abnormality according to the fourth example of the fifth embodiment. In this fourth example, the cleaning member 60 moved to the second position last time, but the first sensor 63 does not detect the absence of the cleaning member, detects that the first sensor 62 is abnormal, and then performs power OFF / ON. Since the first sensor 62 becomes normal at the time of operation this time, the operation is started and it is an example of the case where it is detected that the connector of the second sensor 63 is disconnected or the second sensor 63 is abnormal.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Thereafter, although the cleaning member 60 abnormally ends at the second position, the first sensor 62 remains “H” (abnormal), so the control unit 51 determines that the first sensor 72 is abnormal, The warning is displayed on the operation display unit 13 and the abnormality information data is stored in the database.

  Here, when the power of the control board 50 is turned off, the sensor logic when the power is turned off (strictly speaking, immediately before the power is turned off) is that the first sensor 62 is “H” (abnormal) and the second sensor 63 is “H”. It is. The control unit 51 also stores the sensor logic immediately before the power-off in the database.

  Next, when starting the operation this time, the control board 50 is powered on and turned on. At the start of this operation, it is assumed that the cleaning member 60 is in the second position, and the first sensor 62 changes to the normal state and becomes “H”. Since the first sensor 62 is normal, the control unit 51 starts the movement of the cleaning member 60 from the second position to the first position. However, it is assumed that the cleaning member 60 has moved to the first position normally, but the second sensor 63 has not changed from the presence of the cleaning member to the absence of the cleaning member. In this case, the control unit 51 determines that the connector (second connector 73) of the second sensor 63 is disconnected or the second sensor 63 is abnormal, and displays a warning on the operation display unit 13. Then, the control unit 51 stores, in the database, the sensor logic immediately before turning off when the power is turned off after the current operation and the present abnormality information data (dropping of the second connector 73 or an abnormality of the second sensor 63).

[Fifth example]
FIG. 21 is an explanatory diagram of sensor logic showing an example of motor abnormality detection according to a fifth example of the fifth embodiment. In the fifth example, the moving operation of the cleaning member 60 is normally ended last time, and there is no change in the logic of both the first sensor 62 and the second sensor 63 even if a predetermined time has passed at the time of the moving operation of the cleaning member 60 this time. It is an example of the case. The predetermined time is defined in advance and stored in the non-volatile memory 52.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Thereafter, when the cleaning member 60 moves from the second position to the first position, one operation (cleaning process) ends. The sensor logic after the end of the operation is that the first sensor 62 is “H” and the second sensor 63 is “L”. Therefore, the control unit 51 determines that this operation has ended normally.

  Next, at the start of the operation this time, the control unit 51 instructs the motor 61 to start moving by the driver 53, and there is no change in the logic of the first sensor 62 and the second sensor 63 within a predetermined time. And a warning is displayed on the operation display unit 13. Since the power is not turned off before the start of operation this time, connector omission is excluded from the cause of the abnormality. Then, the control unit 51 stores, in the database, the sensor logic immediately before the power-off after the current operation and the abnormality information data (abnormality of the motor 61).

[Sixth example]
FIG. 22 is an explanatory diagram of sensor logic showing an example of detection of motor connector disconnection or motor abnormality according to a sixth example of the fifth embodiment. In the sixth example, the movement operation of the cleaning member 60 is normally ended last time, and the first sensor 62 and the second sensor 62 are detected even when a predetermined time has passed during the movement operation of the cleaning member 60 after power OFF / ON. 63 is an example when there is no change in logic.

  First, in the previous operation, when the control unit 51 instructs the cleaning member 60 to start moving from the first position to the second position, the sensor logic at the start of movement indicates that the first sensor 62 has the cleaning member present. “H”, and the second sensor 63 is “L” indicating no cleaning member. Then, when the cleaning member 60 moves from the second position to the first position, one operation (cleaning process) ends. The sensor logic after the end of the operation is that the first sensor 62 is “H” and the second sensor 63 is “L”. Therefore, the control unit 51 determines that this operation has ended normally.

  Here, when the control board 50 is powered off, the sensor logic at power off (strictly speaking, immediately before power off) is “H” for the first sensor 62 and “L” for the second sensor 63. The control unit 51 stores information that the cleaning member 60 is at the first position in the database, and ends when the sensor logic of the previous operation is normal when the power is turned off.

  Next, when starting the operation this time, the control board 50 is powered on and turned on. At the start of the operation this time, the control unit 51 instructs the motor 61 to start moving by the driver 53, and there is no change in the logic of both the first sensor 62 and the second sensor 63 within the predetermined time. It is determined that the connector 71 is disconnected or the motor 61 is abnormal, and a warning is displayed on the operation display unit 13. Then, the control unit 51 stores, in the database, the sensor logic immediately before the power off after the current operation and the abnormality information data (the disconnection of the motor connector 71 or the abnormality of the motor 61).

  According to the fifth embodiment described above, the sensor logic at the start of the previous operation of the cleaning member, the sensor logic at the completion of the operation, the states of abnormal end and normal end, and the power supply of the image forming apparatus 1 (control board 50) Save sensor logic just before OFF. Then, the control unit 51 determines from the previous sensor logic at the start of the operation of the cleaning member 60 next time, the result of the abnormal end and normal end, the power OFF / ON state, the sensor logic just before the previous power OFF, and the sensor logic this time. It is possible to pinpoint the abnormal point in detail.

<6. Sixth embodiment>
FIG. 23 is an explanatory view showing a configuration example of a motor current detection function of the control board 50 according to the sixth embodiment.

  As shown in FIG. 23, the control substrate 50 includes a control unit 51, a driver 53, and a current detection unit 54. The control unit 51 supplies the driver 53 with a control signal including a rotational speed command (CONT) and a rotational direction command (F / R). The driver 53 receives the supply of the power supply voltage 24 V, supplies a drive signal to the motor 61, and rotationally drives the motor 61. The current detection unit 54 detects the motor current of the motor 61 sent from the driver 53, and sends a current detection signal to the control unit 51. For example, the current detection unit 54 can be configured using an operational amplifier and a resistor, but not limited to this example, a known configuration can be adopted. The current detection unit 54 detects a motor current by capturing a voltage across a resistor provided between the driver 53 and the ground terminal. The control unit 51 also receives a detection signal of the first sensor 62 and a detection signal of the second sensor 63.

[First example]
FIG. 24 shows an example of a motor current waveform according to a first example of the sixth embodiment.
The horizontal axis of FIG. 24 represents time, the motor CONT of the vertical axis represents the rotational speed command to the motor 61, the first threshold represents the operating current value, and the second threshold represents the overcurrent value. Immediately after the motor CONT is turned ON, the motor current increases, and the control unit 51 determines that the load abnormality of the motor 61 is present when the motor current exceeds the second threshold. The load abnormality means a state in which the load applied to the motor 61 is larger than the setting.

[Second example]
FIG. 25 shows an example of a motor current waveform according to a second example of the sixth embodiment.
The example of FIG. 25 is an example in the case of moving the cleaning member 60 in the first position to the second position. The sensor logic at the start of movement is that the first sensor 62 is "H" and the second sensor 63 is "L". Since the motor current is lower than the first threshold (operating current value) and the motor 61 hardly rotates, the controller 51 does not change to "H" within a predetermined time after the motor CONT is turned on. It is determined that the motor 61 or the driver 53 is abnormal.

[Third example]
FIG. 26 shows an example of a motor current waveform according to a third example of the sixth embodiment.
The example of FIG. 26 is an example in the case of moving the cleaning member 60 in the first position to the second position. The sensor logic at the start of movement is that the first sensor 62 is "H" and the second sensor 63 is "L". If the motor 61 is rotating normally but the second sensor 63 does not change to "H" within a predetermined time, the control unit 51 determines that the gear is idle (gear abnormality).

  As described above, in the sixth embodiment, the current value at the time of driving the motor is detected, and the operating current threshold and the overcurrent threshold are provided. Then, when the sensor of the movement destination is normal, the motor 61 is driven, and the abnormality of the motor 61 and the mechanical abnormality are detected from the operating current value of the motor 61 and the sensor logic of the movement destination.

<7. Seventh embodiment>
Next, a procedure example of the abnormal point specifying process (abnormality diagnosis method for position detection function) in the position detection function by the control unit 51 will be described with reference to FIGS. The abnormal point specifying process of FIGS. 27 to 30 is a combination of the first to sixth embodiments described above. Moreover, the example shown in FIGS. 27-30 is an example in the case of moving the cleaning member 60 in a 1st position at the time of an operation | movement start to a 2nd position.

FIG. 27 is a flowchart (1) illustrating an example of a procedure of abnormal point specification processing in the position detection function according to the seventh embodiment.
FIG. 28 is a flowchart (2) illustrating an example of the procedure of the abnormal point specifying process in the position detection function according to the seventh embodiment.
FIG. 29 is a flowchart (3) illustrating an example of the procedure of the abnormal point specifying process in the position detection function according to the seventh embodiment.
FIG. 30 is a flowchart (4) illustrating an example of a procedure of abnormal point specification processing in the position detection function according to the seventh embodiment.

  In FIG. 27, first, the control unit 51 receives an instruction to move the cleaning member 60 from the first position to the second position (S1). As this movement instruction, there are, for example, one performed according to a predetermined program, and one in which a maintenance worker manually instructs the operation display unit 13 to perform a cleaning process.

  Next, the control unit 51 determines whether the cleaning member 60 is at a position detectable by the first sensor 62 (S2), and if the cleaning member 60 is at a position detectable by the first sensor 62 (S2) And the pull-up power supply to the first sensor 62 is turned off (S3). On the other hand, if the cleaning member 60 is not at the position where it can be detected by the first sensor 62 (NO in S2), the control unit 51 proceeds to step S41 (connector D) in FIG. The pull-up power supply to the first sensor 62 is turned off (S3).

  Next, the control unit 51 determines whether the state of the first sensor 62 has changed from detection (H) to non-detection (L) (S4). The detection state is a state in which the sensor outputs a detection signal (H) indicating that the cleaning member is present, and the non-detection state is that the sensor outputs a detection signal (L) indicating no cleaning member. It is in the state of When the state of the first sensor 62 changes to non-detection (L) (YES in S4), the control unit 51 determines that the sensor detection circuit 50d of the first sensor 62 is normal (S5). On the other hand, when the state of the first sensor 62 is still detection (H) (NO in S4), the control unit 51 determines that the sensor detection circuit 50d (control board 50) of the first sensor 62 is abnormal. The determination is made (S6), and the processing of this flowchart is ended (connector B).

  Next, the control unit 51 determines whether the cleaning member 60 is at a position where it can not be detected by the second sensor 63 (S7), and if the cleaning member 60 is at a position where it can not be detected by the second sensor 63 (YES in S7) The power supply to the second sensor 63 is turned off (S8).

  Next, the control unit 51 determines whether the state of the second sensor 63 has changed from non-detection (L) to detection (H) (S9). When the state of the second sensor 63 changes to detection (H) (YES in S9), the control unit 51 determines that the sensor detection circuit 50d of the second sensor 63 is normal (S10), as shown in FIG. The process proceeds to step S21 (connector C). On the other hand, when the state of the second sensor 63 is not detected (L) (NO in S9), the control unit 51 determines that the sensor detection circuit 50d (control board 50) of the second sensor 63 is abnormal. It is determined (S11) that the processing of this flowchart is ended (connector B).

  On the other hand, when the cleaning member 60 is in the position where the second sensor 63 can detect (NO in S7), the control unit 51 turns off the pull-up power supply to the second sensor 63 (S12). Next, the control unit 51 determines whether the state of the second sensor 62 has changed from detection (H) to non-detection (L) (S13).

  When the state of the second sensor 63 changes to non-detection (L) (YES in S13), the control unit 51 detects removal of the maintenance connector 74 (S14). When the state of the second sensor 63 changes to detection (H) (NO in S13), the control unit 51 determines that the sense detection circuit 50d (control substrate 50) of the second sense 63 is abnormal. To do (S15). After the process of step S14 or S15 ends, the control unit 51 ends the process of this flowchart (connector B).

  Next, after the process of step S10, the control unit 51 determines that the cleaning member 60 is present at the first position (S21). Next, the control unit 51 outputs a command to move the cleaning member 60 from the first position to the second position to the driver 53, and starts the operation of the motor 61 (S22). Next, the control unit 51 determines whether or not the second sensor 63 has detected the cleaning member 60 within a prescribed time after the movement command is issued (S23).

  When the second sensor 63 detects the cleaning member 60 within the prescribed time (YES in S23), the control unit 51 changes the state of the first sensor 62 from detection (H) to non-detection (L) It is determined whether or not it is (S24). When the state of the first sensor 62 changes to non-detection (L) (YES in S24), the control unit 51 determines that the cleaning member 60 has completed moving to the second position, and stops the motor 61. (S25).

  On the other hand, when the state of the first sensor 62 remains the detection (L) (NO in S24), the control unit 51 determines that the first sensor 62 is abnormal (S26). And control part 51 ends processing of this flow chart, after processing of Step S25 or S26 is completed.

  In addition, when the second sensor 63 can not detect the cleaning member 60 within the prescribed time (NO in S23), the control unit 51 detects the motor over current signal by the current detection unit 54. It is determined whether or not (S27). When the motor over-current signal is detected by the current detection unit 54 (YES in S27), the control unit 51 determines that the load abnormality or the actuator abnormality (abnormality of the moving mechanism of the cleaning member 60) is present (S28).

  On the other hand, when the controller 51 does not detect the motor over-current signal by the current detector 54 (NO in S27), whether the controller 51 detects the motor normal current signal by the current detector 54 or not Is determined (S29). When the motor normal current signal is detected by the current detection unit 54 (YES in S29), the control unit 51 determines that the gear is idle (S30). In addition, when the motor normal current signal is not detected by the current detection unit 54 (NO in S29), the control unit 51 determines that the motor 61 is abnormal (S31). And control part 51 ends processing of this flow chart, after processing of Step S28, S30, or S31 is completed.

  Next, when it is determined in step S2 that the cleaning member 60 is not at a position where detection by the first sensor 62 is possible (NO in S2, connector D), the control unit 51 turns off the power supply to the first sensor 62. To do (S41).

  Next, the control unit 51 determines whether the state of the first sensor 62 has changed from non-detection (L) to detection (H) (S42). When the state of the first sensor 62 changes to detection (H) (YES in S42), the control unit 51 determines that the sensor detection circuit 50d of the first sensor 62 is normal (S43). On the other hand, when the state of the first sensor 62 remains undetected (L) (NO in S42), the control unit 51 determines that the sensor detection circuit 50d (control board 50) of the first sensor 62 is abnormal. It is determined that (S49), and the processing of this flowchart is ended (connector B).

  Next, the control unit 51 determines whether the cleaning member 60 is at a position detectable by the second sensor 63 (S44), and if the cleaning member 60 is at a position detectable by the second sensor 63 (YES in S44) And the pull-up power supply to the second sensor 63 is turned off (S45).

  Next, the control unit 51 determines whether the state of the second sensor 63 has changed from detection (H) to non-detection (L) (S46). When the state of the second sensor 63 changes to non-detection (L) (YES in S46), the control unit 51 determines that the sensor detection circuit 50d of the second sensor 63 is normal (S47). It transfers to step S61 (connector E) of FIG. On the other hand, when the state of the second sensor 63 is still detection (H) (NO in S46), the control unit 51 determines that the sensor detection circuit 50d (control board 50) of the second sensor 63 is abnormal. The determination is made (S48), and the processing of this flowchart is ended (connector B).

  In addition, when the cleaning member 60 is not at the position where the second sensor 63 can detect (NO in S44), the control unit 51 turns off the power supply to the second sensor 63 (S50). Next, the control unit 51 determines whether the state of the second sensor 62 has changed from non-detection (L) to detection (H) (S51).

  When the state of the second sensor 63 changes to detection (H) (YES in S51), the control unit 51 determines that the sense detection circuit 50d (control substrate 50) of the second sense 63 is normal ( S52), shift to the step S67 (connector F) of FIG. In addition, when the state of the second sensor 63 is not detected (L) (NO in S51), the control unit 51 determines that the sense detection circuit 50d (control substrate 50) of the second sense 63 is abnormal. It is determined that the process of this flowchart is ended (connector B).

  Next, after the process of step S47, the control unit 51 determines that the cleaning member 60 is present at the second position (S61). Next, the control unit 51 outputs a command to move the cleaning member 60 from the second position to the first position to the driver 53, and starts the operation of the motor 61 (S62). Next, the control unit 51 determines whether or not the first sensor 62 has detected the cleaning member 60 within a prescribed time after the movement command is issued (S63).

  When the first sensor 62 detects the cleaning member 60 within the prescribed time (YES in S63), the control unit 51 changes the state of the second sensor 63 from detection (H) to non-detection (L) It is determined whether or not it is (S64). When the state of the second sensor 63 changes to non-detection (L) (YES in S64), the control unit 51 determines that the cleaning member 60 has completed the movement to the first position, and stops the motor 61. (S65).

  On the other hand, when the state of the second sensor 63 remains in the detection (H) state (NO at S64), the control unit 51 determines that the second sensor 63 is abnormal (S66). End the process (connector B).

  Next, after the process of step S52, the control unit 51 determines that the cleaning member 60 is present at the intermediate position (S67). Next, the control unit 51 outputs a command to move the cleaning member 60 from the intermediate position to the first position to the driver 53, and starts the operation of the motor 61 (S68). Next, the control unit 51 determines whether or not the first sensor 62 has detected the cleaning member 60 within a prescribed time after the movement command is issued (S69).

  When the first sensor 62 detects the cleaning member 60 within the prescribed time (YES in S69), the control unit 51 determines that the cleaning member 60 has completed the movement to the first position and stops the motor 61. (S70). Then, after the process of step S65 or S70, the control unit 51 proceeds to step S1 (connector A), and waits for an instruction to move the cleaning member 60 from the first position to the second position.

  Furthermore, when the first sensor 62 can not detect the cleaning member 60 within the prescribed time (NO in S63, NO in S69), the control unit 51 proceeds to the determination process in step S27 (connector G) .

  In the seventh embodiment described above, as the processing sequence when starting the movement of the cleaning member 60, the control unit 51 confirms that the sensor detection circuit 50d of each sensor is normal, and the movement destination sensor does not have the cleaning member. From the previous sensor information, abnormality occurrence information, power OFF / ON information, and current sensor logic information, it is determined whether or not the movement operation can be started. Then, when it is determined that there is an abnormality, the control unit 51 identifies an abnormal part from the information and does not move the cleaning member 60. On the other hand, when it is determined that there is no abnormality (normal), the control unit 51 starts the moving operation of the cleaning member 60 and determines the presence / absence (normal / abnormal) of the abnormality from the change of the sensor logic.

<8. Modified example>
A stepping motor is used as an example of the motor 61 in each of the above-described embodiments. After determining that the stepping motor is not operating in each embodiment, the control unit 51 changes the number of rotations of the stepping motor to determine load fluctuation. For example, the rotation speed of the stepping motor is reduced to operate. Since the rotational torque of the stepping motor increases as the rotational speed decreases, the control unit 51 checks whether the stepping motor rotates in a state in which the rotational torque is increased. The time required for the cleaning member to reach the movement destination sensor is extended by the decrease in the number of rotations of the stepping motor. Then, when the sensor of the movement destination outputs a signal indicating that the movement member is present, the control unit 51 determines that the stepping motor is in a heavy load state, and displays a load abnormality on the operation display unit 13.

  Further, after determining that the stepping motor is not operating in each embodiment, the control unit 51 may increase the set current value of the stepping motor to operate the stepping motor. When the set current value is increased, the rotational torque of the stepping motor is increased, so the control unit 51 confirms whether the stepping motor rotates in a state where the rotational torque is increased. Then, when the sensor of the movement destination outputs a signal indicating that the movement member is present, the control unit 51 determines that the stepping motor is in a heavy load state, and displays a load abnormality on the operation display unit 13.

  When it is detected that the motor 61 is in a heavy load state, the count number of occurrences is stored as the failure extension processing without stopping the motor 61. Then, when the count number of occurrences exceeds the predetermined count number, the control unit 51 displays a warning indicating an abnormality on the operation display unit 13 and stops the image forming apparatus 1. This limits the decrease in production efficiency to a small extent.

  Furthermore, the present invention is not limited to the embodiments described above, and it goes without saying that various other applications and modifications can be taken without departing from the scope of the present invention described in the claims. is there.

  For example, the above-described embodiment is a detailed and specific description of the configuration of the apparatus and system for the purpose of easy understanding of the present invention, and is not necessarily limited to one having all the components described. In addition, it is possible to replace part of the configuration of one embodiment with the component of another embodiment. In addition, it is also possible to add components of other example embodiments to the configuration of one example embodiment. Moreover, it is also possible to add, delete, and replace other components for part of the configuration of each embodiment.

  Further, some or all of the above-described components, functions, processing units, processing means, etc. may be realized by hardware, for example, by design of an integrated circuit. Further, each component, function, and the like described above may be realized by software by a processor interpreting and executing a program that realizes each function. Information such as a program, a table, and a file for realizing each function can be placed in a memory, a hard disk, a recording device such as a solid state drive (SSD), or a recording medium such as an IC card, an SD card, or a DVD.

  Further, control lines and information lines indicate what is considered to be necessary for the description, and not all control lines and information lines in the product are necessarily shown. In practice, almost all components may be considered to be connected to each other.

  Furthermore, in the present specification, processing steps that describe time-series processing are parallel or individual processing that is not necessarily performed chronologically, as well as processing performed chronologically in the order described. Processing (eg, parallel processing or processing by an object).

  Reference Signs List 1 image forming apparatus 13 operation display unit 24 roller 33 charging unit 33 c electrode cleaning unit 33 w charging wire 37 cleaning unit 50 d sensor detection circuit 51 control unit 55 ... 1st power supply unit, 56 ... 2nd power supply unit, 53 ... driver, 54 ... current detection unit, 57-1, 57-2 ... transistor, 60 ... cleaning member (moving member), 60a ... slide bar, 61 ... motor (Movement drive unit) 62: first sensor 63: second sensor 71: connector for motor 72: first connector 73: second connector 74: maintenance connector

Claims (13)

A moving member moving between a first position and a second position;
A movement drive unit for moving the moving member based on a command input through the movement drive unit connector;
A first position detection sensor provided at the first position and supplied with power via the first connector, and outputting a detection signal according to the position of the moving member via the first connector;
A second position detection sensor provided at the second position and supplied with power via the second connector, and outputting a detection signal according to the position of the moving member via the second connector;
A control unit that determines the position of the moving member using the detection signal output from the first position detection sensor and the second position detection sensor, and controls the operation of the movement drive unit;
In each of the first position detection sensor and the second position detection sensor, logic representing that the moving member is present at each of the first position and the second position, and for the first connector and the second connector The logic representing each connector disconnection and the logic representing an abnormal state of each of the first position detection sensor and the second position detection sensor are the same,
The control unit performs at least an abnormality of the movement driving unit from detection signals of the first position detection sensor and the second position detection sensor before start of movement of the moving member and after start of movement as failure diagnosis of the position detection function. An image forming apparatus configured to determine whether an abnormality of the first position detection sensor or the second position detection sensor or a disconnection of the first connector or the second connector has occurred; A first power supply unit for supplying a first power supply to each sensor via a sensor detection circuit provided corresponding to each of the first position detection sensor and the second position detection sensor;
A second power supply unit for supplying a second power source for pulling up a detection signal of the first position detection sensor or the second position detection sensor corresponding to each sensor detection circuit;
When the detection signal of each of the first position detection sensor and the second position detection sensor indicates that there is a moving member, the control unit is configured to receive the first position detection sensor from the second power supply unit and the first position detection sensor. By stopping the second power supply supplied to the second position detection sensor, the detection signal changes to a signal indicating no moving member, or the first position detection sensor and the second position detection sensor That the first power supply, which has been supplied from the first power supply unit to the first position detection sensor and the second position detection sensor, is stopped when the detection signal of each of And the detection signal corresponding to each of the first position detection sensor and the second position detection sensor is changed by the sensor detection circuit corresponding to each of the first position detection sensor and the second position detection sensor. The image forming apparatus according to claim 1 determines that it can be detected correctly presence. The moving member is at a first position, the first position detection sensor outputs a detection signal indicating the presence of the moving member at a first position, and the second position detection sensor is at a second position. When a detection signal indicating absence is output, or
The moving member is at the second position, the second position detection sensor outputs a detection signal indicating the presence of the moving member at the second position, and the first position detection sensor is at the first position. When a detection signal indicating absence is output, or
When the moving member is present between the first position and the second position, and both the first position detecting sensor and the second position detecting sensor output a detection signal indicating no moving member.
The image forming apparatus according to claim 1, wherein the control unit issues an instruction to the movement driving unit to start movement of the moving member. The control unit outputs a detection signal indicating that the moving member is present at the first position when the moving member is at the first position, and the second position detecting sensor outputs the second detection signal. The second position detection sensor detects a second position when a command to move the moving member to the second position is sent to the movement drive unit from the state where the detection signal indicating no moving member is output to the position of When the first position detection sensor outputs a detection signal indicating the presence of the moving member to the first position, the first connector is disconnected or the first position detection sensor outputs the detection signal indicating the presence of the moving member. 1 Determined that the position detection sensor is abnormal,
Alternatively, the moving member is in the second position, and the second position detection sensor outputs a detection signal indicating the presence of the moving member in the second position, and the first position detection sensor is in the first position. The first position detection sensor moves to the first position when a command to move the moving member to the first position is sent to the movement drive unit from the state where the detection signal indicating no moving member is output. When the detection signal indicating presence is output and the second position detection sensor outputs a detection signal indicating presence of the moving member at the second position, the second connector is disconnected or the second position detection The image forming apparatus according to claim 1, wherein the sensor is determined to be abnormal. The control unit outputs a detection signal indicating that the moving member is present at the first position when the moving member is at the first position, and the second position detecting sensor outputs the second detection signal. The second position detection sensor transmits a command to move the moving member to the second position from the state where the detection signal indicating no moving member is output to the position of When the detection signal indicating the presence of the moving member is not output to the second position, it is determined that the connector for the movement driving unit is disconnected or the movement driving unit is abnormal.
Alternatively, the movable member is at the second position, and the second position detection sensor outputs a detection signal indicating the presence of the movable member at the second position, and the first position detection sensor is moved to the second position. When a command to move the moving member to the first position is sent to the movement drive unit from the state where the detection signal indicating the absence of a member is output, the first position detection sensor moves to the first position within a prescribed time. The image forming apparatus according to claim 1, wherein the movement drive unit is determined to be abnormal when the detection signal indicating the presence of the movement member is not output. And a current detection circuit connected to a motor drive circuit for driving the motor as the movement drive unit and detecting a motor current.
The control unit instructs the motor to move the moving member, and the sensor of the movement destination has a predetermined time while the current detection circuit detects a motor current equal to or higher than an operating current threshold of the motor when the motor rotates. When the detection signal indicating the presence of the moving member is not output, it is determined that the motor is idling due to gear abnormality, and the motor current detected by the current detection circuit is equal to or higher than the overcurrent threshold. The image forming apparatus according to claim 1, wherein it is determined that the load is heavy or mechanical or higher. The connector for the movement drive unit, the first connector, the second connector, and the control unit are connected by wires to a maintenance connector in which the movement member is configured to be removable.
The control unit determines that the maintenance connector is disconnected when both the first position detection sensor and the second position detection sensor output a detection signal indicating that there is a moving member. Image forming device. Furthermore, the logic of the first position detection sensor and the second position detection sensor at the start of operation of the moving member, and the logic of the first position detection sensor and the second position detection sensor at the end of the operation of the moving member And a data storage unit in which abnormality information at the time of abnormality occurrence and the logic of the first position detection sensor and the second position detection sensor immediately before the power supply of the control unit is turned off;
The control unit, when starting the moving operation of the moving member after the previous operation of the moving member ends, the information stored in the data storage unit and the information at the start of the moving operation of the moving member this time The image forming apparatus according to claim 1, wherein the presence or absence of an abnormality in the position detection function is determined from the logic of a first position detection sensor and the second position detection sensor. The connector for the movement drive unit, the first connector, the second connector, and the control unit are connected by wires to a maintenance connector in which the movement member is configured to be removable.
The control unit is configured to normally end the previous movement operation of the movable member, and when the movement operation of the movable member is started after the control unit is turned off and turned on, the first position detection sensor and the second position detection sensor When both of the position detection sensors output a detection signal indicating that there is a moving member, it is determined that the maintenance connector is removed, and after it is determined that the maintenance connector is removed, the power supply of the control unit 9. The image forming apparatus according to claim 8, wherein the logic of the first position detection sensor and the second position detection sensor immediately before the power is turned off is not stored in the data storage unit when the power is off. The movement drive unit is a stepping motor,
After the control unit determines that the stepping motor is not operating, the number of rotations of the stepping motor is decreased to operate the stepping motor, and the sensor of the movement destination outputs a signal indicating that the moving member is present The image forming apparatus according to claim 1, wherein the stepping motor is determined to be in a heavy load state. The movement drive unit is a stepping motor,
After the control unit determines that the stepping motor is not operating, the setting current value of the stepping motor is increased to operate the stepping motor, and the sensor of the movement destination outputs a signal indicating presence of the moving member The image forming apparatus according to claim 1, wherein the stepping motor is determined to be in a heavy load state. When the control unit can normally detect the presence or absence of the moving member by the sensor detection circuit corresponding to each of the first position detection sensor and the second position detection sensor, each sensor detection circuit is normal. Determined that there is
Then, after determining that the sensor detection circuit is normal, the movement operation of the movable member is performed after the previous operation of the movable member is completed in a state where the sensor of the movement destination detects the signal with the movable member. At the time of starting, the position detection function from each information stored in the data storage unit and the logic of the first position detection sensor and the second position detection sensor at the start of the moving operation of the moving member this time If it is determined that there is an abnormality, the movement operation of the moving member is not performed.
In addition, when it is determined that there is no abnormality in the position detection function, the movement operation of the moving member is started, and the position detection function is performed by logical change of detection signals of the first position detection sensor and the second position detection sensor. The image forming apparatus according to claim 8, wherein the presence or absence of an abnormality is determined. A movable member for moving between the first position and the second position, a movable drive unit for moving the movable member based on a command input via the movable drive connector, and the first position A first position detection sensor which is provided with power supply via a first connector and outputs a detection signal according to the position of the movable member via the first connector, and is provided at the second position A second position detection sensor that is supplied with power via a second connector and outputs a detection signal according to the position of the moving member via the second connector, the first position detection sensor, and the second position detection A position detection function abnormality diagnosis method in an image forming apparatus, comprising: a control unit that determines the position of the moving member using the detection signal output from a sensor and controls the operation of the movement drive unit,
In each of the first position detection sensor and the second position detection sensor, logic representing that the moving member is present at each of the first position and the second position, and for the first connector and the second connector The logic representing each connector disconnection and the logic representing an abnormal state of each of the first position detection sensor and the second position detection sensor are the same.
An acquisition step in which the control unit acquires detection signals output from the first position detection sensor and the second position detection sensor before the movement start of the moving member and after the movement start as failure diagnosis of the position detection function;
The control unit is configured to detect at least an abnormality in the movement drive unit from detection signals output from the first position detection sensor and the second position detection sensor before and after the movement start of the movement member. A determination step of performing a process of determining which one of a sensor and an abnormality of the second position detection sensor and a disconnection of the first connector and the second connector has occurred.

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