JPS61292655A - Automatic electrostatic charger cleaning device - Google Patents

Abstract

PURPOSE:To make automatic cleaning over whole charge line by returning a cleaning member to the home position before the cleaning operation of the cleaning member. CONSTITUTION:Charge cleaners are provided in three chargers; a main electrostatic charger CC, a transfer charger TC and a discharger CL. Toner is dispersed and floated in the atmosphere of an image forming device and this sticks to the discharge wire of each charger to fluctuate the condition of image forming and causes the deterioration of an image. By cleaning the discharge wire automatically by the charger cleaner from the home position, a stable image can be obtained. The cleaning of the discharge wire 18 is made by rotating a driving motor 12 at the first time normally and reversely and reciprocating a cleaner pad 17 that holds the discharge wire 18.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a charger (
charger) related to automatic cleaning devices.

(Prior Art) A charger of a copying machine is installed in an environment where it is easily contaminated by developer dust. If the charger wire becomes dirty, its discharge characteristics change, degrading the image forming conditions and making it impossible to obtain a proper image.

Therefore, various measures have been taken to prevent chargers from getting dirty.

Many of the conventional techniques for preventing dirt on chargers are related to scattering of developer dust, which is the cause of dirt, but their effectiveness is small. In scattering prevention technology,
In order to increase the effect, a suction device or the like is necessary, but this requires the device itself to be large and has the disadvantage of being expensive.

In addition, as a means to directly clean the charger wire, there is a method of installing a charger cleaner pad and manually inserting and removing the charger to cause friction between the cleaner pad and the charger wire, but this method does not require service. There were drawbacks such as the need to perform mincing periodically and the maintenance costs were questionable.

(Purpose) The present invention aims to improve the reliability and image quality of copying machines by eliminating the drawbacks of the conventional examples and providing a device that automatically cleans the charger line. .

(Structure) To achieve this, the present invention drives a cleaning member that is in sliding contact with the charger wire using a drive wire, and, prior to the cleaning operation of the cleaning member, first returns the cleaning member to its home position, and then, over the entire area of the charger wire, It is characterized by automatic cleaning.

The configuration of the present invention will be explained below based on the illustrated embodiments.

In the embodiment, charger cleaners are installed in three chargers: a main charger (CC), a transfer charger (TC), and a static eliminator (CLC).

FIG. 1 is an external view showing a charger having a charger cleaner, including a driving DC motor 12, a passive worm gear 13. Drive gear 14. Drive wire pulley 1
5. Pad driving wire 16, cleaning pad 17
．． Discharge wire 2 wire (charger wire) 1st, Passive wire pulley 19° Power receiving terminal 20. It is composed of a casing 21.

FIG. 2 is a schematic diagram of the image forming portion of the copying apparatus. FIG. 3 is a block diagram of the copying machine main control section. FIG. 4 is a charger cleaner drive DC motor drive circuit diagram. Fifth
The figure is a drive DC motor control timing diagram. FIG. 6 is a charger cleaner control circulation diagram. FIG. 7 is a charger cleaner control flow diagram. FIG. 8 is an explanatory diagram of flag data used within a control flow.

First, the image forming operation of the copying apparatus will be explained with reference to FIG.

The photosensitive drum 5 charged by the main charger 9 is exposed to document scanning light at the next slit section 10, and a static image is placed on the drum. A latent image is formed and silence! The latent image is visualized by the developing section 11. On the other hand, the transfer paper 1 is fed by a paper feed roller 2 and 1. The registration roller 3 feeds the image to the transfer section in synchronization with the image on the drum. In the transfer section, the transfer charger 4 transfers the image on the drum to the transferred transfer paper. Then, the transfer paper is attracted to the separation belt and conveyed, and then advances to the next fixing device.

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

As described above, toner is scattered and suspended in the atmosphere of these image forming apparatuses, and this adheres to the discharge wires of the respective chargers, changing the image forming conditions and causing image deterioration.

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

The charger cleaner operation will be explained below.

The discharge wire 18 is swept by the first drive motor 12.
This is done by rotating the discharge wire 18 in forward and reverse directions, and also reciprocating the cleaner pad 17 holding the discharge wire 18 therebetween.

FIG. 3 is a block diagram of the main control section of the copying machine, and the control board 30 includes a micro CPμ, a ROM section, a RAM section, a non-volatile R
It consists of an AM part, a timer part, and a 110 part, and the charger cleaner is also controlled by the control program in the ROM.

Reference numeral 22 (X, to
) to drive.

Next, the forward and reverse rotational driving of the drive DC motor 12 by the drive circuit 22 will be explained based on FIGS. 4(a) and 4(b).

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

A part of the driver is connected to a single power supply VD as shown in Figure 4(b).
The motor is bipolar driven, and forward/reverse control is based on motor lock current detection. In other words, when the DC motor rotates forward (when the cleaner moves forward), the forward rotation signal (a-HIGH,
d-LOW) is output, and in the logic section, A=HIG
Four signals are output: H, B-LOW, C-LOW, and D-HIGH. As a result, motor (M) 12 has +
A current flows from - to -, and the motor 12 rotates in the normal direction.

Also, when reversing, the main control section sends reverse signals (a-LOW, d
-HIGH> is output, and the logic section consisting of ICI to IC8 outputs A-LOW, B-HIGH, C-HIGH,
Four signals called LOW are output, and the motor 12 is -
From 10 to 10, the current is reversed. Also, the motor drive current r
*(reverse current), rr (forward current) are detection resistors R+R
It is converted into a voltage by IC 11, amplified by IC 9 and ICl 0, and input to the comparator ICI 1. Then, forward/reverse control of the motor 12 and abnormality diagnosis control are performed based on the comparator output e.

That is, the level V of the comparator is set as follows.

Positive E time s RgIy (1+R+J/R+z)<Vtb<
Ra1t, C1+Ri+/R+z)...(1)r
L: Drive motor restricted current when reversed: Ra I N (1+ R+o/Rq)
<Vth<R41L(1+R1°/R9)...(2
)Vth-VnR+4/R+a Rtt"" (3) Further, detailed control will be explained with reference to FIGS. 5, 6, 7, and 8.

The flow (OP, CLEANER) in FIG. 7 is a charger cleaner operation subprogram that is called and executed outside the copying operation in the copying machine main control program.

The operation of the charger cleaner is carried out when the power switch of the copying machine is turned on, since the effect is sufficient even if the charger cleaner is cleaned only once a day.

Further, in order to reduce the power supply capacity for driving the cleaner and to reduce the driving noise, each cleaner was driven one by one as shown in FIG. 6. Also, the driving order is OFF of the current SW.
Non-volatile RAM in the main control unit to ensure that it does not go awry even at times.
The drive order DATA is stored in the controller, and the number of times each charger cleaner is cleaned is controlled to be equalized.

When the fixing temperature reaches the copying temperature after turning on the power switch (reload state), after the reciprocating operation of the charger cleaner in operation is completed, the charger cleaner operation is interrupted and the next charger cleaner operation control is not executed. The cleaning operation is reliably executed without interruption during reciprocation of the charger cleaner operation. Furthermore, the copyable state limited by the charger cleaner cleaning time can be minimized.

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

First, a reversal signal is issued, and it is checked whether 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 at the home position. In order to prevent noise erroneous signals, when the constraint signal e is continuously generated for an arbitrarily set time Tc (2 seconds in the example),
It is recognized and processed as a regular signal. Next, the main control section outputs a normal rotation signal a. When the restraint signal e is output, the main control section outputs the reverse rotation signal d again. Then, when the restraint signal e is output, the reverse rotation signal is set to 0FFL, and the reciprocating operation of the charger cleaner is completed. Similar control is subsequently performed for each charger cleaner in sequence, and when the three charger cleaner operations are completed, the charger cleaner operation cycle is completed.

Abnormal operation diagnosis was performed for four cases.

First, in the initial operation (homing operation), if the restraint signal e is not generated for longer than an arbitrary set time (2 seconds or more in the example) (connector not connected, drive wire broken, etc.), 2.3. If the restraint signal e is generated from the peritoneum, which outputs the forward rotation signal for the forward movement and the reverse rotation signal for the backward movement, for longer than an arbitrarily set time (2 seconds or more in the example) (
drive lock due to overload, etc.), and the fourth is forward movement time (T
F) and the return time (TR) is greater than or equal to an arbitrarily set time (4 seconds in the embodiment) (driving abnormality due to overload, etc.). When an abnormality occurs, the abnormality is displayed on the display section within the operation section, and the copying apparatus is controlled to be in a copy inhibited state. By being controlled as described above, 1. the charger cleaner can perform its functional state, and the reliability of the copying apparatus 1. The image quality can be maintained and improved more reliably.

(Effects) The present invention is as described above, and according to the present invention, the cleaning operation of the cleaning member from an uncertain position is prevented after manual operation or after turning off the power of the copying machine during cleaning operation. The cleaning effect of the cleaning device can be ensured.

Further, since the backward movement operation can be confirmed prior to the cleaning operation, troubles in the backward movement control after the forward movement can be prevented.

[Brief explanation 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 diagram of the image forming part of the copying machine, Fig. 3 is a block diagram of the main control section of the copying machine, and Fig. 4 (a), (b)
is a drive motor drive circuit diagram, Figure 5 is a drive motor control timing diagram, Figure 6 is a charger cleaner control circulation diagram, Figure 7 Ca) to (d) are charger cleaner control flow diagrams, and Figure 8 is a control flow diagram. FIG. 3 is an explanatory diagram of usage flag data. 12... Drive motor, 16... Drive wire, 1
7 is a cleaning member, 18...charger wire. Figure 2 Helmet Figure 4 (G) Child 5 Figure c Child 6 Figure

Claims (1)

[Claims] A copying machine comprising a drive wire, a cleaning member fixed to the drive wire and in sliding contact with the charger line, a drive motor for reciprocating the cleaning member, and a home position detection means for detecting that the cleaning member is at the home position. In an automatic charger cleaning device such as a machine, it is detected that the home position signal from the home position detection means is not output, and the cleaning member is driven to the home position, and after detecting the home position signal, the cleaning device is started. An automatic charger cleaning device characterized by controlling its operation.