JPH02308272A - Cleaning device for corona discharger - Google Patents

Abstract

PURPOSE:To avoid the rising of the cost of a device and to prevent the device from being made larger by changing the driving power of a motor which drives a cleaning member for cleaning a corona discharger corresponding to a driving time. CONSTITUTION:One cycle of action of the driving motor 204, that means, timing that a cleaner supporting member 213 moves back after it moves forward and timing that it stops at a home position, is set by a PWM timer 107 which receives a control signal from a control part 100. At first, duty in impressing voltage is set to be 100% and the motor 204 is normally rotated with 100% driving power. Then, the duty in impressing the voltage on the motor 204 is lowered to 80% when time (t1) elapses after driving the motor 204. Furthermore, the duty in impressing the voltage on the motor 204 is lowered to 30% when time (t2) elapses.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for cleaning discharge electrodes and shield members in corona dischargers that charge a photoreceptor used in copying machines, printers, etc. .

[Prior art]

In the copying process in a copying machine, generally, after a corona discharger uniformly charges the surface of a photoconductor, an optical system that optically scans the surface of the document performs an exposure process on the photoconductor.
After forming the electrostatic latent image, a predetermined developer is added to the electrostatic latent image using a developing device.

After that, a transfer device transfers the developed image to a transfer paper conveyed by a conveyance means, and then the transferred image is sent to a fixing device to fix the transferred image to the transfer paper, and after the fixing process, the transfer paper is discharged outside the copying machine. On the other hand, the photoreceptor that has undergone the transfer process is cleaned of residual developer on its surface by a cleaning means such as a blade, and then is placed on standby in preparation for the ninth copying process.

In the above copying process, the uniformity of the charging process by the corona discharger on the surface of the photoreceptor has a great effect on the quality of the copied image obtained as a result of the series of copying processes, so the discharge characteristics of the corona discharger are It must always be stable.

However, inside the copying machine, developer, paper powder, dust, etc. are floating during each copying process, and each time a series of copying processes is repeated,
These floating substances adhere to the discharge electrode of the corona discharger and the shield member surrounding it.

There is a problem that the discharge characteristics become unstable, resulting in a decrease in discharge efficiency and uneven discharge, making it impossible to obtain a good copied image.

Therefore, in place of regular maintenance in which the discharger unit is removed from the copier and cleaned, conventionally, a cleaning member is installed inside the corona discharger that slides into contact with the discharge electrode and the shield member surrounding it to clean it. A method has been adopted in which the corona discharger is connected to a drive wire stretched across a pair of pulleys that are pivotally supported along the corona discharger, and the pulleys are moved back and forth along the discharge electrode by a motor that drives the pulleys in forward and reverse directions for cleaning. There is. In such a system, the following three systems are adopted as a system for driving and controlling the cleaning member within the corona discharger.

The first method is to provide a position detecting means such as a sensor for the cleaning member inside the corona discharger and control the drive of the cleaning member based on a detection signal from the position detecting means.

Second, without providing a position detection means such as a sensor, the cleaning member is driven by applying a constant driving force to the motor for a certain period of time based on a timer or the like, and after a certain period of time, the application of the driving force to the motor is stopped. Thirdly, the cleaning member is driven by a motor and moves without providing a position detection means such as a sensor.

When the end of the corona discharger is reached and the cleaning member stalls, the motor driving the cleaning member is overloaded and the current increases. This increased current value is detected and the motor is controlled to reverse rotation or stop.

[Problem to be solved by the invention]

However, in the first conventional method.

Since a detection means for detecting the cleaning member is provided inside the corona discharger, the cost of the device itself increases.Also, space must be secured for installing the detection means inside the corona discharger, which reduces the size of the device. There is a problem in that it inhibits the development of

In addition, in the second conventional method, the cleaning member must be reliably moved from end to end within the corona discharger, so the maximum driving force must be applied to the motor from the start of the cleaning member. Add a sufficiently long time. As a result, after the cleaning member moves and reaches the end within the corona discharger, an unnecessarily large driving force is applied to the cleaning member, resulting in distortion of the cleaning member.

There are problems such as the wire coming off the bobbin.

Furthermore, in the conventional third method, control is performed by detecting the current value increased due to the applied load on the motor, so a current detection circuit for detecting the current value is required, and the device itself requires a current detection circuit. This results in increased costs. Also,
When the load on the motor increases for some reason while the cleaning member is moving inside the corona discharger.

The current detection circuit falsely detects that the cleaning member has reached the end inside the corona discharger, and at that point causes the motor to rotate in reverse. As a result, if the current detection circuit makes a false detection during normal rotation (forward movement), the cleaning member will rotate backwards as the motor rotates in the middle of the corona discharger, leaving an uncleaned area and corona discharger. There is a risk that the cleaning process inside the discharger will be incomplete. On the other hand, if the current detection circuit incorrectly detects during reverse rotation (double motion), the motor of the cleaning member will stop at the middle part of the corona discharger, and as a result, the cleaning member will also stop at the middle part of the corona discharger, and the copying process will be interrupted. Normal charging of the photoreceptor may be inhibited.

The present invention has been made in view of the above, and avoids an increase in the cost of the device itself and an increase in the size of the device due to the provision of a cleaning member position detection means such as a sensor or a current detection circuit, and also avoids unnecessary installation of the cleaning member. A corona discharger that prevents distortion of a cleaning member or detachment of a wire from a pulley due to the application of a driving force, and further avoids adverse effects on cleaning processing or charging processing due to false detection by the current detection circuit. The present invention provides a cleaning device.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a corona discharger comprising a discharge electrode for discharging and a shield member surrounding the discharge electrode. A cleaning member integrally formed with a member that comes into sliding contact with the members and cleans them; and a cleaning member that connects the cleaning member in a proper position and is stretched around a pair of pulleys that are pivotally supported along the corona discharger. A suspended drive wire, a motor capable of reciprocating the cleaning member connected to the drive wire along the discharge electrode by rotationally driving the pulley, and a driving force of the motor. For example, the control means for changing the duty of the applied voltage to the motor may cause the applied voltage to be higher than the normal time when starting to drive the motor.

The present invention provides a cleaning device for a corona discharger that controls the applied voltage to be lower than normal when the motor is stopped.

[Effect]

The cleaning device for a corona discharger according to the present invention changes the driving force of a motor that drives a cleaning member that performs a cleaning process on a corona discharger depending on the driving time.

For example, by means of a control means that changes the duty of the voltage applied to the motor, the applied voltage is made larger than normal when starting driving the motor, and smaller than normal when driving the motor is stopped.

〔Example〕

Hereinafter, nine embodiments of the present invention will be specifically described based on the drawings.

FIG. 2A is a partially omitted plan view of the cleaning device for a corona discharger according to the present invention, and FIG. 2B is a partially omitted plan view when the cleaning member is located at the home position. Diagram C
FIG. 2 is a cross-sectional view of the corona discharger and the cleaning member taken along a plane perpendicular to the longitudinal axis of the corona discharger. In the above explanatory diagram, there is a discharge electrode 200 that is made of a thin wire and performs a charging process on a photoreceptor (not shown), and a thin sheet metal having a U-shaped cross section (however, a shield member 201, which has a large window perforated in the longitudinal direction on the bottom surface thereof, and uniformizes the discharge characteristics of the discharge electrode with respect to the photoreceptor;

End blocks 202 and 203 made of an insulator are supported at the front and rear ends of the shield member 201 and extend the discharge electrode 200 between them, and a cleaning member, which will be described later, is fixed inside the end block 202. and a reversible rotary motor 204 for driving within the shield member 201.

A worm gear 205 is fixed to the rotating shaft of the reversible motor 204 to transmit the rotational driving force of the reversible motor 204 to the outside, and a worm gear 205 is rotatably supported within the end block 202.
A worm wheel 206 that meshes with the worm wheel 206, a pulley 207 formed integrally with or connected to the worm wheel 206, and a support member 208 provided in the end block 203 that is paired with the pulley 207. Boo I7209 is pivotally supported by the pulley 20
7 and a drive wire 210 that is wound around and stretched around a pulley 209 and is movable in the left and right direction in one drawing, and the wire 21
Hook portions 211.0 to fixedly connect both ends of each. j12 on its side; springs 214 and 215 that are engaged with the support member 208 of the pulley 209 to apply a predetermined tension to the drive wire 210; Support member 2
A cleaner pad 21 is adhesively supported by four pillars 216 provided at the center of the cleaner pad 21 to clean the discharge electrode 200.
7 and the shield member 2 at both ends of the cleaner support member 213.
01 and a cleaner pad 219 for cleaning the inside of the shield member 201, which is adhesively supported by a rising portion 21B provided on the surface facing the shield member 201.

Therefore, the cross-sectional outer diameter of the cleaner support member 213 is:

Both sides of the window, which is approximately equal to the cross-sectional inner diameter of the shield member 201 and is bored at the U-shaped bottom of the shield member 201, fit into grooves formed at the end protruding from the lower surface of the bottom of the cleaner support member 213. guides the movement of the cleaner support member 213 while remaining inclined. Above cleaner pad 2
Suitable materials for the parts 17 and 219 are elastic bodies such as felt, urethane foam, Talalino (trade name), and flocked material.

Further, in FIG. 2B, the cleaner support member 213 is shown.

This shows the state at the home position.

Projection 220 and projection 221 of end block 202
is in contact with the side surface of the cleaner support member as a stopper, but the length of the stopper is

Since 220>221, the cleaner support member 2
13 maintains the inclined state as shown in the figure and stops, and the discharge electrode 200 and the cleaner pad 217 are in a non-contact state. This is to ensure that the discharge electrode 200 is maintained at the adjusted position inside the shield member 201 and to always maintain uniform and stable discharge characteristics with respect to the photoreceptor.

FIG. 1 is a circuit diagram for controlling the present invention. an input interface (not shown) that inputs signals from various parts of the copying machine and sends out manual signals to the data bus;
8. A ROM (not shown) that stores programs for controlling each part of the copying machine, a CPU (not shown) that executes various processes according to the programs stored in the ROM, and 8. A control unit 100 includes a RAM (not shown) that stores results and data, an output interface (not shown) that outputs external control commands, etc. to each part in a predetermined format, and the cleaning member Transistors 101, 102, 103, and 104 serve as drivers for the DC motor 204 driven within the corona discharger, and an inverter 10 that inverts the output from the control section 100.
5°106 and PWM for time-controlling the motor 204.
It consists of a timer 107 and AND circuits 108 and 109 that receive and perform ND control on the output of the PWM timer 107 and the output from the control section 100.

In the above configuration, the operation will be explained based on the operation explanatory diagrams in FIGS. 3 and 4, the timing chart in FIG. 5, and the flow chart in FIG. 6.

In FIG. 2A, when the motor 204 is started, the worm gear 205 rotates counterclockwise when viewed from the output shaft side, and the worm wheel 206 and pulley 2 that mesh with the worm gear 205 rotate in the counterclockwise direction when viewed from the output shaft side.
07 in the counterclockwise direction, the cleaner support member 213 connected to the drive wire 210 leaves the home position shown in FIG. 2B and starts moving rightward in FIG. 1.

At this time, the end portions of the 5 drive wires 210 are provided with a hook portion 211 and a hook portion 212 protruding from the longitudinal center position of the cleaner support member 213 in the same direction by l (see FIG. 3).
When the drive wire 210 is pulled in the direction of the arrow in FIG. The cleaner pad 217 slides in contact with the discharge electrode 200 with the discharge electrode 200 sandwiched therebetween, and cleans it. Similarly, the inner surface of the shield member 4 is also covered with a cleaner pad 21.
9 will be cleaning.

By the above operation, the discharge electrode 200 and the shield member 201
can be cleaned at the same time.

After that, the cleaner support member 213 is attached to the end block 20.
After reaching the third side, the motor 204 rotates in the opposite direction, and the cleaner support member 213 moves back in the direction of arrow B (see Fig. 4). The member 213 is in an inclined state opposite to the forward movement, and moves at an angle of /θ2 as shown in FIG. moves while maintaining almost no contact with the discharge electrode 200.

During the reciprocating movement of the cleaning support member 213 described above, a window (not shown) formed at the bottom of the shield member 201 is inserted into a groove (not shown) formed in the leg part protruding from the lower surface of the bottom of the cleaner support member 213. Both sides fit together, and the portions smoothly guide the reciprocating movement of the cleaner support member 213 and guide the cleaner pad 219 so that it does not come into gentle sliding contact with and support the inner surface of the shield member 201. Cleaner support member 213 returned to the home position shown in FIG. 2B
A protrusion 220 provided on the end block 202 is provided on the side surface of the end block 202.
, 221 come into contact with each other to correct the inclination angle of the cleaner member 213, and each cleaner pad 21 of the cleaner support member 213
7 and the discharge electrode 200 to prevent the discharge electrode 200 from moving out of its predetermined position.

Corona discharge is always performed under the same conditions, so that the photoreceptor is uniformly charged.

At this time, the one-cycle operation of the drive motor 204, that is, the timing when the cleaner support member 213 moves forward and then backward, and the timing when it stops at the home position are determined by the PWM timer 107 that receives a control signal from the control unit 100. Set.

Next, the AND circuit 1
PWM from PWM timer 107 via 08,109
When a signal is output and PA-0 is set to H level and PA-1 is set to L level, transistors 101.10
4 is set ON and the current is IA as shown in FIG.
Force direction flow.

The motor 204 rotates in the normal rotation direction (601).

At the same time, as shown in the timing chart showing one cycle of cleaning operation in Figure 5, the duty of voltage application is increased to 100%.
The motor 204 is rotated in the forward direction with the driving force of 100% (602). Next, it is determined whether L1 time (see FIG. 5) has elapsed since the motor 204 was driven (603), and if E1 time has elapsed since the motor 204 was driven, the duty of voltage application to the motor 204 is set to 80. % and continue to rotate the motor 204 in the normal direction (604)
. Furthermore, it is determined whether two hours (see FIG. 5) have elapsed since the elapse of the L1 time (605), and if t2 hours have elapsed since the elapse of the time t, the duty of voltage application to the motor 204 is changed. The motor 204 is continuously rotated in the normal direction with the reduction to 30% (606). After that, further t2
It is determined whether 3 hours (see FIG. 5) have passed since the time elapsed (607), and t! If the time t1 has elapsed since the time elapsed, PA-0 is set to L level, the drive motor 204 is stopped (60B), and the motor 2
Set the duty of voltage application to 04 to 0% (60
9).

In this way, the driving force for the motor 204 is gradually reduced in accordance with time, so that the cleaning member reaches or has not yet reached the end of the corona discharger during t3 shown in FIG. Even if there is no, the driving force is small, so
Problems such as distortion of the cleaning member or detachment of the wire from the pulley can be avoided.

Thereafter, the motor 204 is in a stopped state.

After the elapse of time (see FIG. 5), similarly to 2, the PWM timer 107 outputs the AND circuit 1 by the control signal from the control section 100.
08 and 109, and contrary to the above case, PA-0 is set to L level and PA-1 is set to H level.

Transistors 102 and 103 are set to ON.

As shown in FIG. 1, the current flows in the I8 direction, and the motor 20
4 rotates in the opposite direction (611). At the same time motor 204
The motor 204 is reversed by setting the voltage application duty to 1ooi (612). Next, it is determined whether 3 hours (see FIG. 5) have passed since the motor 204 was driven (613), and if 3 hours have passed since the motor 204 was driven, the duty of voltage application to the motor 204 is changed. is reduced to 80% and the motor 204 is continuously reversed (614). Furthermore, when the ts time elapses, 8
(615) to determine whether time has elapsed (see Figure 5).
, t, if 6 hours have passed since the time elapsed,
The duty of voltage application to the motor 204 is reduced to 30% and the motor 204 is continuously reversed (616
). Thereafter, it is determined whether one hour has elapsed since 14 hours have elapsed (see FIG. 5) (617), and ti
FA-1 if 1 hour has passed since the time elapsed
is set to L level to stop the drive motor 204 (61
Along with B), the voltage application rate to the motor 204 is set to 0% (619). In the above operation, the cleaning member returns to the home position during tl, and one cycle of the cleaning operation by the cleaning member is completed.

In the above embodiment, a PWM timer is used as an output element of the PWM signal, but the PWM signal can be outputted from the output interface of the control section 100 by using a timer etc. built in the control section 100. By doing so, further cost reduction can be achieved.

〔Effect of the invention〕

As explained above, according to the cleaning device for a corona discharger according to the present invention, the control means changes the driving force of the reversible motor that reciprocates the cleaning member along the discharge electrode according to the driving time. 2. For example, by means of a control means that changes the duty of the voltage applied to the motor, the applied voltage is made larger than normal when starting driving the motor, and the applied voltage is made larger than normal when driving the motor is stopped. In order to control the reduction of .

It is possible to avoid an increase in the cost and size of the device itself due to the provision of a cleaning member position detection means such as a sensor or a current detection circuit, and to avoid distortion of the cleaning member due to unnecessary driving force being applied to the cleaning member. Alternatively, it is possible to prevent the wire from coming off the pulley, and furthermore, it is possible to avoid an adverse effect on the cleaning process or the charging process due to erroneous detection by the current detection circuit.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a circuit for controlling the operation of a cleaning device for a corona discharger according to the present invention, and FIG. 2A is an explanatory diagram. FIG. 2B is a partially omitted plan view of a cleaning device for a corona discharger to which the present invention is applied; FIG. 2B is a partially omitted plan view when the cleaning member is at the home position in FIG. 2A;
FIG. 2C is a cross-sectional view of the corona discharger and the cleaning member taken along a plane perpendicular to the longitudinal axis of the corona discharger, and FIG. FIG. 4 is a partial plan view showing the forward movement state of the cleaning member, FIG. 4 is a partial plan view showing the backward movement state of the cleaning member, FIG. 5 is a timing chart showing the operation of the present invention, and FIG. is a flowchart showing the operation of the present invention. Explanation of symbols 100...-Control unit, 101-104--Transistor 105, 106...-Inverter 107...-PWM timer 108, 109--AND circuit 200...-Discharge electrode, 201-Shield member 202 .203--End block 204--Drive motor 210--Drive wire, 213--Cleaner support member 217.219--Cleaner pad Fig. 5 Stop/Stop

Claims (2)

[Claims] (1) In a corona discharger composed of a discharge electrode that performs discharge and a shield member surrounding the discharge electrode, a member that slides into contact with the discharge electrode and the shield member and cleans them is integrally formed. a cleaning member that connects the cleaning member to a proper position and is stretched between a pair of pulleys that are pivotally supported along the corona discharger; A corona characterized by having a reciprocating motor that reciprocates a cleaning member connected to the discharge electrode along the discharge electrode, and a control means that changes the driving force of the motor in accordance with the driving time of the motor. Discharger cleaning device. (2) In the cleaning device for a corona discharger according to claim 1, the control means for changing the duty of the applied voltage to the motor increases the applied voltage at the start of driving the motor compared to the normal time, and drives the motor. A cleaning device for a corona discharger, characterized in that the applied voltage is lower when stopped than when normally applied.