JPH0675223B2 - Automatic charger cleaning device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic charger cleaning device applied to an image forming apparatus including an image forming process such as a copying machine.

(Prior Art) The charger of a copying machine is installed in an environment where it is easily contaminated by developer dust. If the discharge wire becomes dirty, its discharge characteristics will change and the image forming conditions will be deteriorated, so that an appropriate image cannot be obtained.

Therefore, various measures have been taken to prevent the charger from becoming dirty.

As a conventional technique for preventing stains on the charger, there are many measures for scattering developer dust that causes stains, but the effect is small. In the anti-scattering technique, a suction device or the like is indispensable in order to increase its effect, but for that purpose, the device itself becomes large and the cost is high.

Further, as a means for directly cleaning the discharge wire, there is a means for cleaning by installing a cleaning pad and manually inserting / removing the charger to bring the cleaning pad into contact with the discharge wire. Since maintenance has to be performed regularly, there are drawbacks such as high maintenance costs.

(Purpose) The present invention solves the above-mentioned drawbacks of the conventional example, the discharge wire is automatically cleaned, and an abnormal cleaning operation can be detected before the start of image formation. The purpose is to prevent.

(Structure) To this end, the present invention provides a drive wire, a cleaning member such as a cleaning pad fixed to the drive wire and slidably contacting the discharge wire of the charger, a drive motor for reciprocating the cleaning member, and In an automatic charger cleaning device of an image forming apparatus having a motor lock detection means for detecting the restraint state of the drive motor and outputting a restraint signal, the above-mentioned automatic charger cleaning device for an image forming apparatus is set within a preset time before initial image formation. If the restraint signal does not occur, or if the restraint signal occurs for a set time or more immediately after the forward rotation signal for forward movement of the cleaning member and the reverse rotation signal for backward movement are output,
Alternatively, when the difference between the forward movement time and the backward movement time of the cleaning member is equal to or longer than the set time, the cleaning operation is stopped as an operation abnormality, the image forming operation is prohibited, and the abnormality is displayed.

Hereinafter, the configuration of the present invention will be described based on the illustrated embodiments.

In the embodiment, three chargers, that is, a main charger (CC), a transfer charger (TC), and a charge eliminator (CLC) are respectively provided with automatic charger cleaning devices.

FIG. 1 is an external view showing a charger equipped with an automatic charger cleaning device, including a drive DC motor 12, a passive worm gear 13,
The drive gear 14, the drive wire pulley 15, the pad drive wire 16, the cleaning pad 17, the discharge wire 18, the passive wire pulley 19, the power receiving terminal 20, and the casing 21.

2 is a schematic diagram of the copying machine, FIG. 3 is a block diagram of the main control section of the copying machine, FIG. 4 is a drive circuit diagram of the drive DC motor in the automatic charger cleaning device, and FIG. 5 is control of the drive DC motor. Timing diagram, FIG. 6 is a cleaning circulation diagram of the automatic charger cleaning device, FIG. 7 is a control flow diagram of the automatic charger cleaning device,
FIG. 8 is an explanatory diagram of use flag data in the control flow.

First, the image forming operation of the copying machine will be described with reference to FIG.

The photoconductor drum 5 charged by the main charger 9 is exposed by the original scanning light at the next slit portion 10 to form an electrostatic latent image on the drum, and the electrostatic latent image is visualized by the developing portion 11. Be converted. On the other hand, the transfer paper 1 is fed by the paper feed roller 2 and is fed by the registration roller 3 to the transfer portion in synchronization with the image on the drum. Transfer charger 4 at the transfer section
As a result, the image on the drum is transferred to the transferred transfer paper. Then, the transfer paper is attracted to the separation belt and conveyed, and advances to the next fixing device.

Further, the drum 5 removes the residual charge on the drum by the static eliminator 7, then the residual toner is collected by the cleaning brush 8, and the drum 5 is rotated again to the position facing the main charger 9 to end the image forming cycle. To do.

In the atmosphere of these image forming apparatuses, the toner is scattered and floated, and the toner adheres to the discharge wires of the chargers 4, 7 and 9 to change the image forming conditions and cause the image deterioration. On the street.

Therefore, in the present invention, a stable image can be obtained by automatically cleaning the discharge wire from the home position with the automatic charger cleaning device.

The operation of the automatic charger cleaning device will be described below.

To clean the discharge wire 18, rotate the drive motor 12 forward and backward, and the cleaning pad 17 that holds the discharge wire 18 in between.
This is done by reciprocating.

FIG. 3 is a main control block diagram of the copying machine.
Is composed of a micro cpμ, a ROM section, a RAM section, a non-volatile RAM section, a timer section, and an I / O section. The automatic charger cleaning device is also controlled by the control program in the ROM.

Reference numeral 22 (X _{1 to} X ₃ ) in FIG. ₃ is a drive circuit unit of the automatic charger cleaning device, which drives the drive DC motor 12 (M _{1 to} M ₃ ).

Next, forward / reverse rotation drive of the drive DC motor 12 by the drive circuit 22 will be described with reference to FIGS. 4 (a) and 4 (b).

The drive circuit 22 is divided into a logic section shown in FIG. 4 (a) and a driver section shown in FIG. 4 (b).

As shown in FIG. 4 (b), the driver unit is a bipolar drive with a single power source V _D , and the forward / reverse control is based on detection of a motor restraint current. In other words, the forward rotation signal (a = HIGH, b = LOW) from the main control during DC motor forward rotation (cleaner forward movement).
Is output, and in the logic section, A = HIGH, B = LOW, C
= LOW, D = HIGH, 4 signals are output. As a result, a current flows from + to-in the motor (M) 12, and the motor 12 rotates normally.

Also, at the time of reverse rotation, the main controller outputs a reverse rotation signal (a = LOW, d = H
IGH) is output, and the logic part composed of IC1 to IC8 is A
= LOW, B = HIGH, C = HIGH, D = LOW, four signals are output, and the motor 12 has a current flowing from + to + and reverses.
Also, motor drive current I _R (reverse rotation current), I _F (forward rotation current)
Is converted to a voltage by the detection resistors R ₄ and R ₈ , and IC9 and IC10
Is input to the comparator IC11. Then, forward / reverse control of the motor 12 and abnormality diagnosis control are performed by the comparator output e.

That is, the level V _{th of the} comparator is set as follows.

Forward _{rotation: R 8 I F (1 +} R 11 / R 12) <V th <R 8 I L (1 + R 11 /
R ₁₂ ) ... (1) I _L : Drive motor restraint current Reverse rotation: R ₄ I _R (1 + R ₁₀ / R ₉ ) <V _th <R ₄ I _L (1 + R ₁₀ / R)
₉ ) (2) V _th = V _D R ₁₄ / R ₁₄ -R ₁₃ (3) Further, detailed control will be described with reference to FIGS. 5 to 8.

The flow (OP.CLEANER) of FIG. 7 is an operation sub-program of the automatic charger cleaning device, which is called and executed outside the copying operation in the copying machine main control program.

The operation of the automatic charger cleaning device is performed when the power switch of the copying machine is turned on because the effect of cleaning once a day is sufficient.

In addition, in order to reduce the drive power source capacity of the automatic charger cleaning device and reduce the drive noise, one by one in order.
As shown in the figure, the static eliminator (CLC) 7, the main charger (CC) 9, and the transfer charger (TC) 4 are driven in this order. In addition, the driving order data is stored in the nonvolatile RAM of the main control unit so that the driving order does not get out of order even when the power switch is turned off, and control is performed so that the number of times of cleaning of each automatic charger cleaning device is made uniform. .

After the power switch is turned on, when the fixing temperature reaches the copy enable temperature (reload state), the operation control of the next automatic charger cleaning device is not executed after the reciprocating operation of the operating automatic charger cleaning device is completed. As a result, the cleaning operation is performed from the reliable home position without interrupting the operation of the automatic charger cleaning device during reciprocation. Further, the copyable state, which is limited by the cleaning time of the automatic charger cleaning device, can be minimized.

The operation timing of each motor 12 is as shown in FIG.

First, a reverse rotation signal is output and it is confirmed whether or not the cleaning pad 17 is at the home position (start position). When the restraint signal e is output, it is determined that the vehicle is in the home position. In order to prevent a noise erroneous signal, the restraint signal e is recognized as a normal signal when continuously generated for an arbitrary set time T _C (2 seconds in the embodiment). Next, the main control unit outputs the normal rotation signal a. When the restraint signal e is output, the main control unit outputs the reverse rotation signal b again. When the restraint signal e is output, the reverse rotation signal b is turned off, and the reciprocating operation of the automatic charger cleaning device is completed. Thereafter, similar control is sequentially performed for each automatic charger cleaning device, and when the operation of the three automatic charger cleaning devices ends, the operation cycle ends.

The abnormal operation diagnosis is performed for four cases.

First, in the initial homing, when the restraint signal e is not generated within an arbitrary set time (2 seconds or more in the embodiment) (connector is not contacted, drive wire is broken, etc.),
Secondly, immediately after the forward rotation signal a for the forward movement of the cleaning pad 17 and the reverse rotation signal b for the backward movement of the cleaning pad 17 are output, the restraint signal e is generated for an arbitrary set time (2 seconds or more in the embodiment) If (drive lock due to overload etc.),
Fourthly, when the difference between the forward movement time (T _F ) and the backward movement time (T _R ) of the cleaning pad 17 is an arbitrarily set time (4 seconds in the embodiment) or more (drive abnormality due to overload etc.). .

When an abnormality occurs, the cleaning operation is stopped, the abnormality is displayed on the display section in the operation section, and the copying machine is controlled to the copy prohibited state. By controlling as described above, the automatic charger cleaning device can execute its functional state, and the reliability and image quality of the copying machine can be maintained and improved more reliably.

(Effect) The present invention is as described above. According to the present invention, the drive abnormality of the automatic charger cleaning device can be detected before the image formation of the image forming apparatus, so that the formation of a defective image can be prevented. I can.

[Brief description of drawings]

FIG. 1 is an external view of an automatic charger cleaning device according to an embodiment of the present invention, FIG. 2 is a schematic view of a copying machine, FIG. 3 is a block diagram of a main controller of the copying machine, and FIG. ) And (b) are drive motor drive circuit diagrams, FIG. 5 is a drive motor control timing diagram, FIG. 6 is a control circulation diagram of an automatic charger cleaning device, and FIGS. 7 (a) to 7 (d) are automatic. FIG. 8 is a control flow diagram of the charger cleaning device, and FIG. 8 is an explanatory diagram of use flag data in the control flow. 4 ... Transfer charger, 7 ... Static eliminator, 9 ... Main charger, 12 ... Drive motor, 16 ... Drive wire, 17 ... Cleaning pad (cleaning member), 18 ... Discharge wire, 22 ... Drive circuit, 30 ...
Control plate, a ... Forward rotation signal, b ... Reverse rotation signal, e ... Restraint signal,
T _F … forward time, T _R … backward time.

Claims (1)

[Claims] 1. A drive wire, a cleaning member fixed to the drive wire and slidably contacting a discharge wire of a charger, a drive motor for reciprocating the cleaning member, and a restrained state of the drive motor. In an automatic charger cleaning device of an image forming apparatus having a motor lock detection means for outputting a restraint signal when the restraint signal is not generated within a set time during initial homing before starting image formation, or when cleaning is performed. If the constraint signal is generated for a set time or more immediately after the forward rotation signal for forward movement of the member and the reverse rotation signal for backward movement are output,
Alternatively, when the difference between the forward movement time and the backward movement time of the cleaning member is equal to or longer than the set time, the cleaning operation is stopped as an operation abnormality, the image forming operation is prohibited, and the abnormality is displayed. Device automatic charger cleaning device.