JP3419944B2 - Automatic charger cleaning device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically cleaning a charger wire of a charger, and in particular, but not by way of limitation, a threaded rod which is substantially parallel to a longitudinally stretched charger wire. ， The screw rod is screwed to this and the screw rod is positive,
A slider that moves forward and backward by reverse rotation, and a cleaning member that is supported by the slider and is in sliding contact with the charger wire;
Also, the present invention relates to an automatic charger cleaning device provided with a driving means mainly composed of an electric motor for driving the screw rod in forward and reverse directions.

[0002]

2. Description of the Related Art In, for example, an electrophotographic printer, a copying machine, etc., a main charging charger for charging positive or negative charges on a photosensitive member and a toner image on the photosensitive member are transferred onto a sheet. For this purpose, a transfer charging device or a separating charging device for separating the paper from the surface of the photoconductor is used. The charger wire for corona discharge used in these various chargers usually has a diameter of 60 to 10
It is a tungsten wire of about 0 μm, and its discharge electrostatically attracts fine particles such as dust, Si, and toner powder in the air. As a result, the fine particles are accumulated on the surface of the charger wire, and the discharge uniformity of the charger wire is deteriorated with time, resulting in deterioration of recording image quality. In order to prevent these problems and obtain a stable image, a method of automatically cleaning the charger wire has recently been adopted, for example, after the recording of a set number of sheets is completed. Specifically, a method has been widely adopted in which a cleaning pad for cleaning the charger wire is pressed against the charger wire and moved to clean the entire length of the charger wire. The following method is practically used for moving the cleaning pad.

1. Wire system: A drive wire and a pulley are used to drive the pulley to rotate to move the cleaning pad fixed to the wire; 2. Feed shaft system: A spiral feed shaft, that is, a screw rod is driven to rotate, A slider screwed on the feed shaft is moved along the feed shaft and cleaned by a cleaning pad mounted on the slider (for example, Japanese Utility Model Laid-Open No. 4-101561).

The following methods have been put to practical use for controlling the reversing operation and the stopping operation of the drive motor at the time of cleaning: 1. Sensor method: Position sensors are provided at the home position and reversing portion of the slider to detect the slider. Then, the drive motor is switched to the reverse drive or stopped (Japanese Patent Application Laid-Open No. 61-292655, Japanese Patent Application Laid-Open No. 1-284).
874); 2. Current detection method The overload current of the drive motor, that is, the binding current is detected when the slider collides with the abutting member at the reversing portion and the home position, and the drive motor is switched to the reverse driving or stopped. (Japanese Patent Laid-Open No. 61-292
655).

In the case of the combination of the feed axis system and the current detection system, when the slider hits the stopper surface and the motor current increases, the energization of the motor is stopped. Start driving. For example, when the slider is placed at the home position on one end side of the feed shaft (screw rod) and cleaning is performed by one reciprocating motion,
The motor is driven in the forward direction to drive the slider toward the other end (reversal end) of the feed shaft. During this drive, the motor current is monitored, and if it exceeds the set value, the slider will move to the stopper surface. If the motor is hit, the motor energization is stopped there, and this time the motor is driven in reverse rotation to drive the slider toward the home position (return drive), and the motor is driven during this drive. The current is monitored, and if it exceeds the set value, the slider is contacted with the stopper surface (returned to the home position) and the motor energization is stopped there.

[0006]

However, in the above-mentioned sensor system, there is a problem that the cost is high and erroneous detection occurs due to dirt or damage of the sensor. In addition, although the above current detection method has high reliability against troubles due to damage of the element, since a brush motor which is generally inexpensive is used, the motor may deteriorate due to deterioration of the motor or abrasion of the reciprocating mechanism. The characteristics of the output torque and the number of revolutions with respect to the drive current have changed, and there has been a problem that erroneous detection of the restrained state occurs over time.

An object of the present invention is to prevent the above-mentioned inconveniences of the current detection system, that is, to effectively prevent erroneous detection of a restrained state due to changes with time such as motor characteristics or wear of the reciprocating mechanism. .

[0008]

SUMMARY OF THE INVENTION An automatic charger cleaning device according to the present invention is a functional member of a conventional current detecting type automatic charger cleaning device, which is a cleaning member slidingly contacting a charger wire of the charger; An electric motor for driving the charger wire in a direction in which the charger wire extends; a motor driver for supplying a forward or reverse driving current to the electric motor; a current detecting means for detecting a driving current of the electric motor; A drive which instructs the motor driver to rotate in the normal direction and instructs the motor driver to stop when the drive current value detected by the current detecting means is equal to or more than a set value, and instructs the motor driver to drive in the reverse direction to be detected by the current detecting means. In addition to the cleaning control means (40: FIGS. 13 and 14) for instructing the motor driver to stop when the current value exceeds the set value, the cleaning member has reached the movement end where mechanical movement is blocked. When said electricity The average value of the restraint current values corresponding to the drive current value detected by the flow detecting means, that is , the restraint current value.
And a coefficient Kp less than or equal to the minimum constraint current value / maximum constraint current value
The reference value setting means to set the product obtained by multiplying the set value (40: FIG.
9-12);

[0009]

Since the set value is determined on the basis of the actual restrained current value of the electric motor, the movement termination due to the variation of the electric motor or the variation of the reciprocating mechanism and the change with time of the output characteristics or the load characteristics of them. Erroneous stop before arrival or excessive energization at the end of movement is eliminated. If the motor is locked
If the brush and commutator in the motor have a positional relationship
For example, sampling should be performed because the constraint current changes.
When the constraint current is the maximum value,
If the new reference value is used, the next constraint current is below the maximum value.
If it does, detection will not be possible. However,
Minimum constraint current value / maximum constraint current value to average value of bundle current value
Set the product obtained by multiplying the following coefficient Kp to the set value
As a result, such a problem does not occur. Restrained state
It is possible to effectively prevent malfunctions due to changes in.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0011]

【Example】

—First Embodiment— FIG. 1 shows a main part of an embodiment of the present invention in a partially disassembled state, and a plan view of the main part shown in FIG. 2a is a side view as seen in the direction of line 2B in FIG.
(B) of. The spiral feed shaft 2 for reciprocally driving the cleaning pad 1 has a charger wire 5
It is arranged parallel to A and 5B. A gear 4 is fixed to one end of the feed shaft 2, and a rotary shaft of an electric motor 8 stored in a drive motor unit 8U attached to a main body (printer or copying machine) is attached to the gear 4. The connected gears 3 mesh with each other. A pair of sliders 6A and 6B are screwed (screwed) to the feed shaft 2. When the electric motor 8 rotates forward, the feed shaft 2 rotates clockwise when viewed from the gear 4 side, and the sliders 6A and 6B move from the home position shown in FIG. Move to.

A cleaning pad 1 for cleaning the charger wires 5A and 5B is attached to the tips of sliders 6A and 6B which move along the feed shaft 2. The sliders 6A and 6B are parallel to the x and y planes of the case 7 of the charger, and are located between the copy guides, which are a pair of bent portions that project above the feed shaft 2 and face each other. The pair of bent portions are movable in the y-direction, but are restrained in the x-direction orthogonal thereto. As shown in FIG. 2, the distance between the tip of the bent portion on the slider 6A side of the case 7 and the tip of the bent portion on the slider 6B side, that is, the gap width, is, as shown in FIG. 2, a start end region Ff (home position region) and an end region Fr.
In the (reversal region), the width becomes wider as it approaches the end blocks Ef and Eb. The end portion of the guide member 7f is fixed to the end block Ef. The base portion of the guide member 7f is thinned toward the cleaning area Fc. Sliders 6A, 6
B is guided by the bent portion of the case 7, and the start end region Ff
When it enters, the tip of the guide member 7f is inserted between the sliders 6A and 6B as it approaches the end block Ef, and the sliders 6A and 6B are bent together with the bent portion of the case 7.
Guides to gradually widen the distance between the two as they approach the end block Ef. When the sliders 6A and 6B reach the end block Ef (the home position is set at this time), the cleaning pad 1 is separated from the charger wires 5A and 5B.

When the sliders 6A and 6B are in the start end region Ff, the cleaning region Fc and the end region Fr, the sliders 6A and 6B viewed in the 3A line direction, 3B line direction and 3C line direction of FIG. 2A. The enlarged front views of the above are shown in (a), (b) and (c) of FIG. 3, respectively. Sliders 6A, 6
When B is in the home position (FIG. 1, FIG. 2, and FIG. 3 (a)), the sliders 6A and 6B have a wide gap width in the bent portion of the case 7, and the slider extends from the inside to the outside by the guide member 7f. The cleaning pad 1 is expanded because it receives a force, and the cleaning pad 1 is separated from the charger wires 5A and 5B.

Next, the forward rotation of the electric motor 8 causes the feed shaft 2 to rotate clockwise as viewed from the gear 4 side, and the sliders 6A, 6
When B moves in the direction of arrow A shown in FIG. 2A and reaches the cleaning region Fc, the gap width of the bent portion of the case 7 becomes narrower, and the sliders 6A and 6B are guided by the gap width of FIG.
(A) is closed in the direction indicated by the arrow. That is, in the cleaning area Fc, the sliders 6A and 6B are moved to the cleaning area Fc shown in FIG.
As shown in FIG. 3, the charge wires 5A and 5B are sandwiched between the cleaning pads 1 and proceed. When the sliders 6A and 6B reach the reversal region Fr, the gap width of the bent portion of the case 7 that guides the sliders 6A and 6B becomes wider again, and the restraining force of the sliders 6A and 6B on the charge wires 5A and 5B becomes weaker. The charge wires 5A and 5B are expanded by the force of returning to their original positions (c in FIG. 3).

FIG. 4 shows a schematic configuration of a control system of a copying machine equipped with the charger shown in FIG. First, the CPU 40, RA
A control unit using a microcomputer including M41, ROM 42, EEPROM 47 (nonvolatile memory), input / output port buffer amplifiers 43, 44, etc. is provided.
The ADF 60 and the exposure optical system 50 are controlled by serial communication between the terminals T × D, R × D and CP2 of U40. In this serial communication, when the output of PC2 is at H level, the ADF 60 and the control section of the copying machine communicate with each other, and when the output of PC2 is at L level, the exposure optical system 50 and the control section of the copying machine communicate. It is configured to communicate. Here, the microcomputer of the ADF 60 performs the paper feeding / discharging process of the document and the jam detection based on the data transmitted from the control unit of the copying machine. On the other hand, the exposure optical system 5
The microcomputer of 0 drives and controls the scanner and the mirror by the data transmitted from the control unit of the copying machine. In this copying machine, the CPU 40 is provided with a sheet selecting means, a sheet reusing means, a defective printing preventing means, a conveyance resuming means, and the like in firmware.

Incidentally, in synchronization with the rotation of the photosensitive member, the pulse generator 45 generates a synchronization pulse of one pulse for each rotation of the minute angle, and the control unit of the copying machine here is the synchronization pulse generator 45. Based on the count value of the pulse that occurs, the transfer paper feed control, the document feed control, and the image forming process (especially timing control) are performed. The synchronizing pulse is generated by the pulse generator 45 in synchronization with the rotation of the photoconductor and is given to the CPU 40. The CPU 40 executes an interrupt process for each arrival of one pulse, counts up the number of incoming pulses, and compares the count value with the count value of the timing table (table storing the relationship between the count value and the event). Then, when one count value of the table is matched, the event (on / off of the image forming element) addressed to the count value is executed.

Motor driver 8A and voltage switching circuit 3
3 is connected to the I / O & buffer 44, and receives a command from the CPU 40 via this. The motor driver 8A detects the drive current ir of the electric motor 8 and outputs an analog voltage representing the drive current ir to the CPU via the I / O & buffer 44.
40 A / D conversion input ports.

FIG. 5 shows the configuration of the motor driver 8A for energizing the electric motor 8, and FIG.
Output signals S1, S2, S3 (via O & buffer 44)
The state and the area where the sliders 6A and 6B exist are shown in a time chart. When the CPU 40 sets the motor drive command S1 to the motor driver 8A to "L" and the motor drive command S2 to "H" (via the I / O & buffer 44), Q5 turns on and Q6 turns off, and the electric motor 8 Q2 and Q4 of the motor driver 8A are turned on, a forward drive current flows to the electric motor 8, the electric motor 8 rotates normally, and the slider 6
A and 6B move in the direction indicated by arrow A in FIG. 1 (forward movement).
Conversely, the motor drive command S1 is "H", the motor drive command S
When 2 is set to "L", Q5 turns off and Q6 turns on,
Q1 and Q3 of the motor driver 8A are turned on, a reverse drive current flows to the electric motor 8, the electric motor 8 reverses, and the sliders 6A and 6B move in the direction indicated by arrow B in FIG. 1 (return movement). . That is, the motor drive command S1 and the motor drive command S2 drive the electric motor 8 and determine the rotation direction thereof, and thus the traveling direction of the sliders 6A and 6B (directions indicated by arrows A and B in FIG. 1). It is a thing. This relationship is shown in Table 1 below.

[0019]

[Table 1]

The CPU 40 controls the current flowing in the resistor R ₀ connected to the emitters of Q3 and Q4 of the drive circuit, that is, the mode.
The analog voltage value Vr proportional to the drive current value Ir is digitally converted and read to recognize the drive current value ir flowing through the electric motor 8. When the sliders 6A and 6B enter the start end region Ff or the end region Fr outside the cleaning region and approach the end block Ef or Eb, the gap width of the case 7 expands as shown in FIG. 2 and the drive current value ir decreases. To do. Conversely, when the cleaning area Fc is entered from the start end area Ff or the end area Fr, the drive current value ir increases. Therefore, by monitoring the value of the current flowing through the resistor R ₀ , it is possible to recognize the movement from the cleaning region Fc to the start end region Ff or the end region Fr, and vice versa. CPU40
The current flowing through the resistor R ₀ is a threshold EI1 (Figure 1
5) It is recognized as the start end region Ff or the end region Fr if it is below, and if it exceeds the threshold value EI1, the cleaning region Fc.
Recognize that.

The voltage switching command S3 sets the applied voltage V _M to the motor / motor driver 8A. Figure 6
The internal circuit of the switching circuit 33 is shown in FIG. The switching circuit 33 in this embodiment uses the regulator REG on the low voltage side. The rated voltage Vs supplied to the electric motor 8 is supplied from the power supply terminal V _D. When the voltage switching command S3 is "L", the NPN transistor Q8, which is a switching element, is turned on and the transistor Q9 is turned off. Therefore, the rated voltage Vs supplied from the power supply terminal V _D is set.
Is supplied as it is to the motor driver 8A from the motor power supply terminal V _M. On the other hand, since the transistor Q8 is turned off with the transistor Q9 is turned on when the voltage switching command S3 "H", the low voltage VL ducks depressurized than the rated voltage Vs by a regulator REG - data supply terminal V _M Yorimo - Is supplied to the driver 8A.

The CPU 40 sets the voltage switching command S3 given to the voltage switching circuit 33 to "H" so that the voltage is low when the sliders 6A and 6B are in the start region Ff and the end region Fr outside the cleaning region. . Then, when the sliders 6A and 6B are in the cleaning area Fc, the voltage switching command S3 given to the voltage switching circuit 33 is set to "L" so as to become the rated voltage Vs. Table 2 shows these relationships.

[0023]

[Table 2]

In the present embodiment, a voltage reducing circuit using a regulator REG is used for switching between the rated voltage Vs and the low voltage VL in order to improve the reliability in consideration of the stability of the circuit in the switching circuit 33. However, in order to reduce costs, a circuit in which a resistor and a switching element are simply connected in parallel may be used.

In any case, since the low voltage VL is applied to the electric motor 8 when it is in the start end region Ff and the end region Fr outside the cleaning region, the sliders 6A and 6B are pressed against the end blocks Ef and Eb. The force (restraint torque) becomes lower than that when driven at the rated voltage Vs, and the output power (starting load) decreases at the next motor start. Therefore, the rush current (starting current) to the electric motor 8 should be reduced. It is possible to prevent deterioration of the motor.

FIG. 7 shows an outline of the control operation of the CPU 40. When the power is turned on, the CPU 40
Counters, timers, etc. are set to standby values, and signal levels in standby are set to the input and output ports of the mechanical unit (step 101). Below, in parentheses,
The word "step" is omitted and only the step number is shown.

When the initialization (101) is completed, the CPU 40
Reads the state of the mechanical unit and checks for any abnormality (state in which image formation cannot be started) (102, 10
3) If there is an abnormality, it is displayed on the operation board 46 (112). If there is no abnormality, the operation is waited for the input of the operation board 46 through the subroutine "charger cleaning" CCC, and if there is an input, the corresponding processing is performed (104). Here, copy number input, copy magnification input, recording density input, etc.
Write what was input to the register. The register means the internal memory of the CPU 40, the RAM 41 or the EEPR.
This is a memory area assigned to the OM 47.

If there is a start input, an operation button to that effect is displayed.
The CPU 40 displays the start and end timings for charging, exposing, erasing, feeding, developing, transferring, etc. for one image formation (recording one image). The timing table is set in correspondence with the copy mode (standard mode when there is no input, standard value for parameters without input) (105, 106).

When the timing setting (106) is completed, one copy cycle (one image forming process) is executed, the copy number counter (register) is incremented by 1 (107), and the register ET assigned to the EEPROM 47 is added.
Increment the contents of C and ECC by 1 (CC
P). The register ETC is a register E for counting the number of accumulated copy sheets for maintenance of the copying machine.
CC is for managing the cleaning timing of the charger.
As will be described later, cleaning of the charger (ACC in FIGS. 13 and 14) is executed immediately after the power of the copying machine is turned on after the data in the register ECC becomes equal to or higher than the set value CCS. Upon completion, the register ECC is cleared there (initialized to a data value 0) (55 to 56 in FIG. 8).

Referring again to FIG. Check whether the number of copies (number of times the image has been formed) has reached the set number (10
8) If the set number has not been reached, another copy cycle (107) is executed. When the set number is reached, cleaning (duration time) of the photoconductor and transfer belt
After that, the post-processing (end cycle) is set (109) and the operation board 46 waits for an input (104). When there is no start input from the operation board 46 and the end cycle ends, the rotation drive of the photoconductor is stopped, the charge eliminating lamp is turned off, and then the end cycle is stopped (105,
110, 111). That is, the mechanical unit is placed in a standby state (stop).

FIG. 8 shows the contents of the subroutine "charger cleaning" (CCC) shown in FIG. When proceeding to this subroutine, the CPU 40 checks whether the data of the register EIP assigned to the EEPROM 47 is 0 (first power-on after assembly of the copying machine) (51). When the data of the register EIP is 0, the "reference value initial value setting" (CCI) shown in FIGS. 9 and 10 is executed, and the register EIP is set to 1 (when the copying machine is assembled, the first power is turned on. The responded setting values EI2L, EI2 and EI1 have been set) are written (52). In addition, these set values EI2
L, EI2 and EI1 mean the data of the registers EI2L, EI2 and EI1 of the EEPROM 47, and the "cleaning control" (ACC) to be described later indicates that the cleaner pad 1 is at the end of movement (reverse position or home position). ) Has been reached, an abnormal lock (abnormal stop) has occurred on the traveling path, and whether the current position is within the region (Ff, Fr) near the terminal end are used as set values (reference values).
The contents of the “reference value initial value setting” (CCI) will be described later with reference to FIGS. 9 and 10.

Referring again to FIG. "Cleaning the charger" (C
CC), when the data of the register EIP is 1, the data E of the register ECN of the EEPROM 47 is
It is checked whether CN (the number of times cleaning has been completed after updating the reference value) is greater than or equal to the set value CNS (51, 53). Set value CNS
If it is above, "update of reference value" (CCR) is executed, and the register CNS is cleared (initialized to the number of cleaning completed 0) (54). The contents of "Update reference value" (CCR) are shown in Fig. 1.
1 and FIG. 12, which will be described later.

Next, the register ECC of the EEPROM 47
Check whether the data ECC (cumulative number of copies from the previous cleaning to the present) is the set value CCS or more (55), and if it is CCS or more, "cleaning control" (ACC)
Is executed to clear the register ECC (initialize the number of copies after cleaning to 0) (56), and delete the register ECN.
The ECN (the number of times cleaning has been completed after updating the reference value) is incremented by 1 (57).

"Charger cleaning" (CCC) explained above
However, as shown in FIG. 7, since it is executed immediately after the copying machine power is turned on, and since the content is as described above, immediately after the first powering on after assembling the copying machine, the "reference value initial value setting" is performed. (CCI) is executed, and after that, the number of copies (1
The cumulative value ECC of the number of executions of the copy cycle) is the set value C
"Cleaning control" immediately after the first power-on after reaching CS
(ACC) is executed and the ECC is initialized to 0. Then, immediately after the power is turned on for the first time after the number ECN of executions of "cleaning control" (ACC) reaches the set value CNS (integer), "update of reference value" (CCR) is executed and ECN is initialized to 0. It

Next, the contents of the "reference value initial value setting" (CCI) will be described with reference to FIGS. Here, the CPU 40 first starts the electric motor 8 in the normal rotation at the low voltage VL (61). That is, the voltage switching command S3 to the voltage switching circuit 33 is set to "H" and the low voltage VL is supplied from the power supply terminal VM to the motor driver 8A, and the motor driving command S1 to the electric motor 8 is set to "L". S2 is set to "H" to drive the electric motor 8 in the normal direction. Then, the counting of the internal timer T for counting the elapsed time T is started (62). As a result, the sliders 6A and 6B at the home position (FIG. 1) start to move in the A direction shown in FIG. 1 (outward path).

The CPU 40 then waits for the activation time tm to elapse (63). As shown in FIG. 15, the start-up time tm is until the high current at the moment when the voltage VL is applied to the electric motor 8 which has been stationary falls below a predetermined level due to the start of rotation of the electric motor 8. During this activation time tm, since S4 is L and the bypass relay 34 is open, the activation current flows to the current detection resistor R ₀ ,
The resistance R ₀ also suppresses the starting current level. The timing, time value, and reference value are shown in FIG.
Please refer to.

When the startup time tm has passed, the CPU 40 executes S
4 is switched to H (64). By this, bypass relay
Since the resistor 34 is closed and the resistor R ₀ is short-circuited, the motor applied voltage has a low value VL, but the motor drive current increases and the output torque of the electric motor 8 increases. Sliders 6A, 6B
The CPU 40 instructs the motor driver 8A to stop the motor 8 at the timing t1 (elapsed time) when the start end area Ff approaches the end (66). Then, the electric motor 8 is reversely started at the low voltage VL (67). That is, the voltage switching command S3 to the voltage switching circuit 33 is set to "H" to supply the low voltage VL from the power supply terminal VM to the motor driver 8A, and the motor drive command S1 to the electric motor 8 is set to "H", Electric motor 8 with S2 set to "L"
Is driven in reverse (67). As a result, the sliders 6A and 6B separated from the home position (FIG. 1) in the direction A start to return toward the home position. That is, it starts to move in the direction B shown in FIG. 1 (return path). Then, in order to detect the value of the motor drive current, S4 is set to L (bypass relay).
34) and return (68). Then, at a predetermined cycle ts, the mode is
The controller drive current ir is digitally converted and read, and it waits until it becomes a fixed value Ips or more (return to the home position) (69 to 73). The fixed value Ips is a reference value set in the ROM 42.

When the motor drive current ir exceeds the fixed value Ips (the sliders 6A and 6B return to the home position), the CPU 40 digitally outputs the motor drive current ir mS times in a predetermined cycle ts. It is converted, read, and written in the data table (one area of RAM) (69 to 77). When the data collection for mS times is completed, the CPU 40 instructs the motor driver 8A to stop the motor 8 (78), and calculates the average value irm of the read data for mS times (79). This average value irm is the average of the restraint currents during ts × mS (time width) of the drive currents (restraint currents) that returned to the home position on the return path and motor rotation became impossible (motor lock). It is a value.

The CPU 40 next calculates the calculated average value irm.
Is multiplied by a coefficient Kp, and the obtained product is written in the register EI2L assigned to the EEPROM 47 (80). next,
A coefficient Ka is added to the product (data EI2L of the register EI2L).
And the obtained product is written in the register EI2 assigned to the EEPROM 47 (81). Next, the average value irm
Multiplied by a coefficient Kp (data E of register EI2L
I2L) is multiplied by a coefficient Kd, and the obtained product is stored in the EEPROM 4
Write to register EI1 assigned to 7 (82).
These data EI2L, EI2 and EI1 are shown in FIG.
5 represents the level shown in FIG. 5, and in a "cleaning control" (ACC) described later, a threshold value (set value) for determining the movement end arrival of the cleaner pad, an abnormality in the cleaning area of the cleaner pad 1, respectively. The threshold (set value) for overload determination and the cleaner pad 1 are located outside the cleaning area in the vicinity of the end (F
It becomes a threshold value (setting value) for determining whether it is in f, Fr).

The coefficient Kp is Kp ≦ minimum constraint current value / maximum constraint current value based on the minimum constraint current value and the maximum constraint current value of the motor 8 measured before equipping the copying machine with the charger. The value is determined and stored in the ROM 42. When the motor 8 is in a restrained state (the state in which rotation is mechanically restrained), the restraint current value changes depending on the relative positional relationship between the brush and the commutator in the motor. When the constraint current when the driving current value is sampled (read) is the maximum value and this value is set as the threshold value (EI2L) as it is, when the next constraint current is less than the maximum value, It becomes impossible to detect the arrival at the end (restraint current). The above-mentioned coefficient Kp is for avoiding such a defect. As mentioned above, EI
By setting 2L = Kp × irm, the overload energization due to the leakage of the end arrival detection of the cleaner pad 1 due to the variation of the restraining current of the motor 8 is avoided.

The coefficient Ka is the threshold value E for determining the end arrival.
The threshold value EI2 for overload detection during traveling in the cleaning area is determined corresponding to I2L, and this is also stored in the ROM 42. The coefficient Kd defines a threshold value EI1 for determining whether or not the vehicle is traveling in the vicinity of the end area (Ff, Fr) outside the cleaning area, corresponding to the threshold value EI2L for determining the end arrival. This is also ROM 42
It is stored in. In this way, the thresholds EI2L and EI1 are also set to values proportional to the constraint current (irm).

Next, the contents of the "reference value update" (CCR) will be described with reference to FIGS. The content of this "update of reference value" (CCR) is the same as the above-mentioned "setting of initial value of reference value" (CCI), the corresponding step number is the same, A is added to the number, and "reference Update Value "
Each step of (CCR) is shown. "Update Reference Value"
(CCR) is different from "initial setting of reference value" (CCI) in step 72A. In step 72 of "Initial setting of reference value" (CCI), the cleaner pad 1
While the fixed current detection threshold value of the ROM 42 is set to the fixed value Ips of the ROM 42 when is returned to the home position,
In step 72A of "update of reference value" (CCR), the data EI2L of the register EI2L is used. EI2L
Is determined (following) on the basis of the average value irm of the actual restraint current, and the terminal restraint is caused by the change over time of the restraint current of the electric motor 8 and the wear of the cleaner pad reciprocating mechanism. Since it corresponds to the change in the characteristics of the load, the termination lock detection is performed more accurately.

Even in this "update of reference value" (CCR), the data EI is set to a value proportional to the average value Irm of the restricted current.
2L, EI2 and EI1 are updated. As a result, stable end lock detection is performed over time.

Next, the content of the "cleaning control" (ACC) will be described with reference to FIGS. FIG. 15 shows the change in the electrical signal that is produced by the "cleaning control" (ACC). The CPU 40 first sets all of the instruction signals S1 to S4 to L and clears the register FLG (1).

Then, the electric motor 8 is started with the low voltage VL (2). That is, the voltage switching command S3 to the voltage switching circuit 33 is set to "H" and the low voltage VL is supplied from the power supply terminal VM to the drive circuit 8A, and the motor driving command S1 to the electric motor 8 is set to "L" and S2. Is set to "H" to drive the electric motor 8 in the normal direction. Then, the internal timer T for counting the elapsed time T starts counting (3A). As a result, the sliders 6A and 6B at the home position (FIG. 1) start to move in the A direction shown in FIG. 1 (outward path).

The CPU 40 then waits for the activation time tm to elapse (3B). As shown in FIG. 15, the start-up time tm is until the high current at the moment when the voltage VL is applied to the electric motor 8 which has been stationary falls below a predetermined level due to the start of rotation of the electric motor 8. During this activation time tm, since S4 is L and the bypass relay 34 is open, the activation current flows to the current detection resistor R ₀ ,
The resistance R ₀ also suppresses the starting current level. The timing, time value, and reference value are shown in FIG.
Please refer to.

When the starting time tm has passed, the CPU 40 executes the S
Switch 4 to H (3C). By this, bypass relay
Since the resistor 34 is closed and the resistor R ₀ is short-circuited, the motor applied voltage has a low value VL, but the motor drive current increases and the output torque of the electric motor 8 increases. Sliders 6A, 6B
The CPU 40 returns S4 to L (bypass relay 34 open) in order to detect the value of the motor drive current at the timing t1 (elapsed time) approaching the end of the start end region Ff, and the reference value for overload judgment ". I2 / L ”is set to a threshold value EI2 (register EI2 data for judging overload during traveling in the cleaning area).
Data), and a reference value "I1" for determining whether the vehicle is traveling in the region near the end (Ff, Fr) is set in EI1 (data of the register EI1) (5).

Then, the motor applied voltage is switched to the rated value Vs (7). This switching increases the motor drive current value and accelerates the sliders 6A and 6B.
Since the cleaning area Fc is changed to the cleaning area Fc, the forward movement load increases and the speed increase of the sliders 6A and 6B is small.

The CPU 40 determines that the measured value of the internal timer T is t.
The motor drive current value is repeatedly read until it reaches 2, and it is checked whether it is the overload reference value "I2 / L" or more (8, 9). When the overload reference value "I2 / L" or more,
Since the cleaning area Fc is overloaded, the motor drive is stopped at that point, and the abnormality indicator lamp for the charger shown in FIG. 1 of the operation indicator board 35 is turned on (10). This abnormality may be due to the fact that a hard and relatively large deposit is adhered to the charger wire, an obstacle (eg, paper) is present in the slider guide portion of the case 7, or some abnormality in the slider drive system. To be

Now, when the time t2 elapses while the motor drive current value is less than the overload reference value "I2 / L", the CPU
40 repeatedly reads the motor drive current value ir, and when it falls below "I1", considers that the sliders 6A and 6B have entered the end region Fr from the cleaning region Fc and writes 1 to the register FLG. (13), the motor applied voltage is switched to VL (15), and the overload reference value "I2 /
L "is changed to the threshold value EI2L (data of the register EI2L) for detecting the termination constraint current (16). When the motor drive current value ir exceeds "I2 / L", the motor
Drive is stopped (17, 18).

At this time, if the content of the register FLG is 1, the sliders 6A and 6B move from the cleaning area Fc to the end area F.
r, and the sliders 6A and 6B hit the end block Eb, the motor drive current ir is changed to the reference value (I2 /
L = EI2L) or more, that is, assuming that the sliders 6A and 6B normally move forward and reach the reversal position (end of movement), the process proceeds to the backward drive control shown in FIG. 14 (11-17). -18-21). The contents are the same as those of the forward drive control described above.

The motor drive current ir is the reference value (I2 / L)
When the content of the register FLG is 0 when the above is reached, from the cleaning area Fc of the sliders 6A and 6B to the end area F.
The motor drive current ir has exceeded the reference value (I2? L = EI2, high value) without a decrease in the motor drive current due to the entry into r, and the cleaning area Fc (or the end area Fr). In this case, the motor drive is stopped and the abnormality indicator lamp addressed to the charger (charger) in the operation indicator board 35 is turned on (1).
1-17-19). This abnormality is caused by charger wire 5
It is conceivable that a hard and relatively large adherent adheres to A and 5B, that there is an obstacle (for example, paper) in the slider guide portion of the case 7, or some abnormality of the slider drive system.

The time t3 is reached without the motor drive current ir reaching the reference value I2 / L (high value EI2 or low value EI2L).
When the time elapses, the motor drive is stopped and the operation display board 4
The abnormality indicator lamp of 6 which is addressed to the charger is turned on (12-2
0). This abnormality is considered to be an abnormality in which no current flows through the electric motor 8, that is, a disconnection abnormality of the motor energization loop, or a charger not installed.

According to the first embodiment described above, the "initial setting of reference value" (CCI) is executed immediately after the first power-on after the copying machine is assembled, and the sliders 6A and 6B are moved from their home positions. The fact that the sliders 6A and 6B are returned to the home position by the forward drive and the backward drive (restricted current) is detected by comparing the current ir of the motor 8 with the reference value Ips set in the ROM 42. . When the restraint current is detected, the motor drive current ir is sampled mS times, and the average value of them is calculated to determine the restraint level (irm) in the actual restraint state. Then, the calculated average value i rm is multiplied by a preset coefficient Kp. In order to use this value EI2L = Kp × irm as a reference value for detecting the terminal restraint state from the next time, EEPRO
It is stored in (register EI2L of) M47. Then, in subsequent "update of reference value" (CCR), detection of return of the sliders 6A and 6B to the home position (home position output) and detection of end restraint in wire cleaning operation are performed. EEPROM4 is used as the reference value.
7 (the register EI2L thereof) is used. The coefficient Kp is calculated in advance by the following formula and stored in the ROM 42.

Kp ≦ motor minimum restraint current / maximum restraint current This is because the restraint current changes depending on the positional relationship between the brush and the commutator in the motor when the motor is restrained.
For example, when the constraint current at the time of sampling is the maximum value, if this value is used as it is as the new reference value, detection cannot be performed when the next constraint current is less than the maximum value. Such a problem will not occur if the coefficients having the relation of the above equation are multiplied. By multiplying the coefficient, it is possible to effectively prevent a malfunction due to a change in the restraint state.

Thus, when the power is turned on for the first time, the motor 8
By obtaining the new reference value from the actual restraint current, it is possible to prevent malfunction of the charger cleaning device due to motor variations.

Further, as the motor 8 is used, the efficiency is lowered due to the abrasion of the brush and the abrasion of the bearing, and the current and rotation characteristics with respect to the torque are changed as shown in FIG. Therefore, when the reference value is fixed, the output torque with respect to the same current becomes small over time, and the sliders 6A and 6B are stopped halfway or the restraint state is erroneously detected. However, in the first embodiment described above, The above problem is prevented by updating the reference value each time the product is input. That is, the information (EIP) for determining whether the power is turned on for the second time after the copying machine is assembled is stored in the EEPROM 47.
Are stored in the register EIP assigned to the first register, and “initial value setting of reference value” (CCI) is performed in the case of the first time, and “update of reference value” (CCI) in the case of the second time or later.
In CR), the same control is performed by reading the reference value from the register EI2L of the EEPROM 47. These "initial setting of reference value" (CCI) and "update of reference value" (CCR) are performed immediately after the power is turned on, and it is possible to prevent abnormal operation due to variations in the motor, and to perform stable cleaning operation even over time. I can do it. "Update reference value" (CC
Also in R), the multiplication of the coefficient can effectively prevent a malfunction due to a change in the restraint state.

In the above-described first embodiment, the cleaning of the charger ("cleaning control" ACC) is performed by setting the copy number CCS as the number of copies.
It is carried out every time it exceeds. And the cleaning frequency is the set value C
Update of standard value every time NS is exceeded (“update of reference value” CC
Since R) is performed, it is possible to flexibly cope with changes in motor characteristics over time and stabilize the cleaning operation. Even in the usage mode in which the power is turned on a few times (the power-on time is long), if the number of copies is large during one power-on, the "cleaning control" ACC, immediately after the next power-on,
The "update of reference value" CCR is executed and a sufficient effect is exhibited. Since the “update of reference value” CCR is set to 1 / CNS (integer) of the number of times the charger is cleaned (the number of times the “cleaning control” ACC is executed), the charger is replaced when the number of times the charger is cleaned reaches a predetermined value. When notifying the necessity and managing the replacement of the charging device, by setting the predetermined value to an integral multiple of CNS, when the charging device is replaced with the predetermined value and the power is turned on, the "update of reference value" CCR is displayed. The threshold value EI2L for detecting the arrival of the moving end is promptly updated with respect to a large change in load caused by replacement of the charger, and the adaptability for replacement of the charger is high.

In the first embodiment, the copying case extending in the y-direction.
In the movement termination regions Ff and Fr, the slider 7 allows the electric motor 8 to drive the sliders 6A and 6B, and the movement of the pad 1 in the direction away from the charger wires 5A and 5B. In the cleaning area Fc between Fr, the pad 1 is forced in the direction in which it is pressed against the charger wires 5A and 5B. Therefore, the drive load of the sliders 6A and 6B is applied to the charger wires 5A and 5B in the cleaning area Fc.
Is large due to the frictional force caused by the pressure contact with the case 7 and the frictional force forcing the pad 1 by the case 7.
At f and Fr, since these frictional forces are absent or small, the slider 6A, 6B drive load is small.

Therefore, the starting load when the sliders 6A and 6B are forward driven from the home position is small, and the forward rotation starting current level of the electric motor 8 is correspondingly low. When the sliders 6A, 6B move to the cleaning area Fc, the sliders 6A, 6B
Although the load of B becomes large, the sliders 6A and 6B are already running, that is, the rotation speed of the electric motor 8 is increasing, and there is no static friction or static inertia.
The increase in the drive current of the drive 8 is low. When the sliders 6A and 6B move from the cleaning area Fc to the movement end area Fr, the above-mentioned frictional force is reduced and the drive current of the electric motor 8 is reduced. When the sliders 6A, 6B hit the stopper, that is, when the slider 6A, 6B reaches the reverse position, the drive current increases there. This is the set value EI
When 2L is reached, the motor energization is stopped, and the electric motor 8 is energized in the reverse direction to start the return drive. The set value EI2L for determining the arrival of the reverse position is a low value because the traveling loads of the sliders 6A and 6B in the movement termination region Fr are small. That is, it is a value corresponding to a load that is considerably high with respect to the traveling loads of the sliders 6A and 6B in the movement termination region Fr, and is set to a low value as the traveling load is low. This suppresses the motor current when reaching the reverse position to a low level. The change in the drive current of the electric motor 8 when the electric motor 8 is reversely started from the reverse position to drive the sliders 6A and 6B back to the movement end region Ff is opposite to the above-described forward drive process. . As described above, the moving end area F
Since the motor drive currents in f and Fr are low, the forward drive and reverse drive start-up currents in the movement end regions Ff and Fr are low, and the stop restraint by the stoppers in the movement end regions Fr and Ff. Since the current (the overload reference value EI2L that determines it) is determined to be low, the overcurrent energization of the electric motor 8 is greatly suppressed.

Second Embodiment The hardware configuration of the second embodiment is the same as that of the first embodiment shown in FIGS. However, the copy control main flow of the CPU 40 (FIG. 7 in the first embodiment) is as shown in FIG.
Changed as shown in and "Clean Charger" CCC
(FIG. 8 in the first embodiment) is changed as shown in FIG. The other control and processing operations of the second embodiment are similar to those of the above-mentioned first embodiment. Therefore, the second
Control and processing operations of the embodiment different from those of the first embodiment will be described.

Referring to FIG. 17, the CPU of the second embodiment
After finishing the "initialization" (101), the 40 starts the timer Tmd for measuring the elapsed time. This starts timekeeping. The measured value of this timer Tmd is waiting for input (104-105-110-111-113-114-
During 104), it is added to the data ETD of the register ETD allocated to the EEPROM 47, and the addition sum is updated and written in the register ETD (113). And timer T
md is restarted (114). Since this is repeated while waiting for input, the duration of power-on of the copying machine is added to the register ETD. When the copier powers off,
Since the register ETD is not updated as described above, the value immediately before the power is turned off is maintained. Therefore, in the data ETD of the register ETD, the power of the copying machine is repeatedly turned on and off.
It is the cumulative value of the power-on duration of each time.

Referring to FIG. 18, the CPU of the second embodiment
Immediately after the power is turned on after the second time after the copying machine is assembled, the reference numeral 40 checks whether the data ETD (accumulated value of power-on duration) of the register ETD is the set value TDS or more (5
1, 53), and if so, "Update Reference Value" (CCR)
Is executed to clear the register ETC (initialize to accumulated value 0) (54). The contents of the “update of reference value” (CCR) are the same as those shown in FIGS. 11 and 12.

As described above, according to the second embodiment, the "update of reference value" (CCR) is executed immediately after the next power-on when the accumulated value of the power-on duration becomes equal to or more than the set value TDS. Threshold values EI2L, EI2, EI1 are set to follow load fluctuations caused by changes in the surface condition of the charger wire or the case due to the power-on time in addition to the contamination of the charger wire due to image formation. To be In particular, when the image forming duty (image forming processing time during the power-on period) is short, it is effectively adapted to the load fluctuation of the charger.

Incidentally, in the copying machine or printer of the mode in which the number of times of cleaning of the charger is counted, and when it reaches the set value, a notification prompting the replacement of the charger is given, and then the presence or absence of replacement of the charger is automatically monitored, In response to the detection of the replacement of the charger, the "reference value update" (CCR) is performed immediately after the power is turned on thereafter. As a result, the adaptability for replacing the charger is high.

[0066]

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a first embodiment of the present invention in a partially disassembled state.

2A is a plan view of the main part shown in FIG. 1 as viewed in the direction of line 2A, and FIG. 2B is a side view as viewed in the direction of line 2B.

3A is an enlarged front view of the sliders 6A and 6B in the starting end region Ff as viewed from the direction of the line 3A shown in FIG. 2, and FIG. 3B is a diagram showing the sliders 6A and 6B being cleaned. An enlarged front view seen from the direction of the line 3B shown in FIG. 2 when in the region Fc, (c) shows that when the sliders 6A and 6B are in the end region Fr, the direction of the line 3C shown in FIG. It is the enlarged front view seen.

4 is a block diagram showing a configuration of an electric control system of a copying machine incorporating the charger shown in FIG.

5 is a block diagram showing a configuration of a motor driver 8A shown in FIG.

6 is an electric circuit diagram showing an internal circuit of a switching circuit 33 shown in FIG.

FIG. 7 is a flowchart showing an outline of a copy control operation of the CPU 40 shown in FIG.

FIG. 8 is a flow chart showing the contents of the “charger cleaning” CCC shown in FIG. 7.

FIG. 9 is a flowchart showing a part of the contents of the “reference value initial value setting” CCI shown in FIG. 8.

FIG. 10: “Initial value setting of reference value” CCI shown in FIG.
It is a flow chart showing the rest of the contents of.

FIG. 11 is a flowchart showing a part of the contents of the “update reference value” CCR shown in FIG.

FIG. 12 is a flowchart showing the remaining contents of the “update reference value” CCR shown in FIG.

FIG. 13 is a flowchart showing a part of the content of “cleaning control” ACC shown in FIG. 8.

FIG. 14 is a flowchart showing the remaining part of the contents of “cleaning control” ACC shown in FIG. 8.

15 is a time chart showing changes in signals S1 to S4 and changes in motor drive current, which are caused by "cleaning control" ACC shown in FIG. 8, of CPU 40 shown in FIG.

16 is a graph showing the relationship between the drive current and the output torque of the electric motor 8 shown in FIG. 1, and the relationship between the output torque and the rotational speed.

FIG. 17 is a flowchart showing an outline of copy control operation of the CPU 40 according to the second embodiment of the present invention.

FIG. 18 is a flowchart showing the contents of “charger cleaning” CCC shown in FIG. 17.

[Explanation of symbols]

1: Cleaning pad 2: Feed shaft 3: Gear 4: Gears 5A, 5B: Charger wire 6A, 6
B: Slider 7: Case of charger 8: Electric motor 8U: Motor drive unit 8A: Motor
Driver 40: CPU 33: voltage switching circuit 34: bypass relay 46: operation / display board Ff: start end area Fr: end area Fc: cleaning area Ef, E
b: End blocks Q1 to Q9: Transistors

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/02 G03G 15/16 102

Claims (2)

(57) [Claims] 1. A cleaning member slidably contacting a charger wire of a charger; an electric motor for driving the cleaning member in a direction in which the charger wire extends; a motor for supplying a positive and a reverse driving current to the electric motor. Motor driver; current detection means for detecting the drive current of the electric motor; the motor driver is instructed to perform normal rotation drive, and when the drive current value detected by the current detection means exceeds a preset value, the motor is driven.
Cleaning control means for instructing the motor driver to stop and then instructing the motor driver to stop when the drive current value detected by the current detecting means exceeds a set value by instructing reverse driving. Corresponding to the drive current value detected by the current detecting means when the end of the movement is blocked, that is , the binding current value, the minimum value of the binding current value is set to the minimum value.
The product of the constraint current value / a coefficient Kp less than or equal to the maximum constraint current value.
The reference value setting means to set said set value; charger automatic cleaning device comprising a. Wherein the reference value setting means for each time series accumulated value of power-on time of the charging device using device exceeds a predetermined value, and sets the setting <br/> value, according to claim 1 Automatic charger cleaning device.