JPH0876640A - Photoreceptor driving device - Google Patents

Abstract

PURPOSE: To execute a minute reverse rotation of the photoreceptor with a positioning accuracy even if the timing accuracy of ON/OFF control of a driving motor is incompetent. CONSTITUTION: The photoreceptor driving device for driving-controlling a photoreceptor drum 101 carrying the image by driving motor 110, is provided with a control part 114 for controlling rotation of the drive motor 110 so that the rotating signal of the reverse direction is imparted with respect to the rotation of the photoreceptor drum 101 at the time of right after the image forming operation, and during the time the photoreceptor drum 101 is stopped by the reverse rotation of the motor, the rotation of the drive motor 110 is controlled to be rotated in the forward direction for a specified time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor driving device used in an image forming apparatus such as a copying machine or a laser printer, and more specifically, it controls reverse rotation / forward rotation of a photoconductor immediately after image formation. However, the present invention relates to a photoconductor driving device that makes the stop position highly accurate.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a foreign matter such as toner or paper dust that has been slightly hardened is sandwiched between a cleaning blade and a photosensitive drum after a copying operation and left for a long time. If it is left, the cleaning property may be deteriorated. Therefore, the conventional photoconductor driving method is
In order to remove the foreign matter, the photosensitive drum is rotated in the reverse direction after the completion of the JOB such as the copying operation, and the operation of removing the trapped foreign matter is performed. The reverse rotation amount in the reverse rotation operation is preferably about 1 mm or more on the surface of the photosensitive drum, and the upper limit is also preferably the distance from the cleaning blade to the inlet seal.

FIG. 8 is a flowchart showing a control process of a conventional photoconductor driving device. In the figure, when copying is started, first, a copy operation (JOB) is executed (S801). After finishing this job, WA
IT1 is set (S802), and a reverse rotation signal (for example, a counterclockwise rotation signal if the rotation during image formation is clockwise) is output to the drive motor that drives the photosensitive drum (S803). Then, WAIT2 reverse rotation is executed for a fixed time (S804), and the reverse rotation signal is stopped (S80).
5).

For example, due to reasons such as productivity (material reservation) and cost reduction, drive motors of slightly different characteristics but generally having the same specifications are generally purchased in parallel and controlled by a single control device. It was Further, part of standard specifications (for example, copy speed) is changed in the model configuration of the image forming apparatus to increase the model series. Further, when a plurality of types of drive motors are prepared, conventionally, a signal line for determining the type of the drive motor is provided to discriminate the drive motor, or input to a storage device in the device when the drive motor is assembled.

Further, as a reference technical document related to the above, for example, an "electrostatic transfer type copying machine" is disclosed in JP-A-63-36286. This charges the photoreceptor
Before rotating in the process direction of exposure / development, minute rotation is performed in the direction opposite to the process direction to remove the paper dust and the like sandwiched between the photoconductor and the cleaning blade. Further, Japanese Patent Laid-Open No. 63-278087 discloses a "cleaning device for a copying machine". This is because after the photoconductor is rotated at the end of copying, the free end of the cleaning blade is separated from the photoconductor, and when the photoconductor is rotated again at the restart, the toner on the photoconductor is left unwiped. It is intended to prevent defective cleaning due to scattering and paper dust attached to the tip of the blade.
Further, Japanese Unexamined Patent Publication No. 3-91788 discloses a "photoconductor cleaning method for an image forming apparatus". In this method, after the cleaning process of the photoconductor is performed, the photoconductor is rotated in the reverse direction to remove adhered matters such as toner and paper dust accumulated on the tip portion of the cleaning blade with a fur brush.

[0006]

However, in the conventional photoconductor driving device as described above, the JO
After the end of B, it was difficult to stop the photosensitive drum at a desired position because the reverse rotation signal of a short time was simply given to the drive motor. This is because the rising speed of the drive motor is set to a large value in order to achieve the standard (for example, the first copy time) during the normal image forming operation. Therefore, 1 to several mm
In order to reversely rotate the photosensitive drum to stop it, the drive motor can be reversely rotated for a very short time. Therefore, the mechanical load, inertia, torque generated at the start of the drive motor, variations in motor control, etc. There was a problem that it would be greatly received.

Further, when a plurality of types of drive motors are controlled by one control device, the rising acceleration of reverse rotation may differ depending on the type of drive motor. However, when the reverse rotation control is executed at the same control timing, the rotational characteristics of the drive motors are not the same, so the reverse rotation amount of the photosensitive drum is different. Therefore, when all the drive motors are controlled by one control device, it is extremely difficult to suppress the desired reverse rotation range amount. Further, in order to deal with a desired reverse rotation range amount for all types of drive motors, it is general to perform the above-mentioned conventional technique so that the rising torques during reverse rotation of all drive motors are the same. To do this, there is a problem that the cost increases and the economic efficiency decreases. In addition, there is a problem that it also affects the specifications of the rise time during forward rotation.

Further, when a plurality of types of drive motors are prepared and a signal line for determining the type of the drive motor is provided to discriminate the drive motor, new signal terminals are provided to the drive motor and the control circuit in the image forming apparatus. There is a problem in that the cost increases due to the provision. In addition, when inputting data to the storage device in the device when the drive motor is assembled, it is possible that an assembly input error, an input error when exchanging the drive motor, or an input error may occur.
Further, there is a problem that the data in the storage device is destroyed due to a runaway of the device due to a current leak in the image forming device, which causes a situation in which the data must be input again.

The present invention has been made in view of the above, and makes it possible to execute a minute reverse rotation of a photoconductor with high position accuracy even when the time accuracy of the ON / OFF control of the drive motor is low. Is the first purpose.

In the case where a plurality of drive motors are prepared, the optimum control corresponding to the drive motors is realized, the standard change of the device is not required, and the economical efficiency thereof is improved. To aim.

Further, in the case where a plurality of drive motors are prepared, the determination can be made even if a hardware member such as a signal line or a terminal for the determination is not necessary, and further, a setting error for each drive motor is caused. The third purpose is to improve the economy and workability by eliminating the above.

[0012]

In order to achieve the above object, in a photoconductor drive device according to a first aspect of the present invention, in a photoconductor drive device for controlling rotation of a photoconductor carrying an image by a drive motor. , Giving a rotation signal in the opposite direction to the rotation of the photoconductor immediately after the end of the image forming operation, and controlling the rotation of the drive motor so that the photoconductor further rotates forward for a certain period while the photoconductor stops due to the reverse rotation. It is provided with a control means for controlling.

Further, in the photoconductor drive device according to the present invention, the control means controls the rotation time of the reverse rotation ON time, the forward rotation ON time after the reverse rotation, or both of them by a drive motor. It is to be changed for each type.

Further, in the photoconductor drive device according to the second aspect of the present invention, the control means executes the discrimination of the drive motor by reversing the logic of the state detection signal of the drive motor.

[0015]

In the photoconductor driving device of the present invention (claim 1), the control means gives a rotation signal in the opposite direction to the rotation of the photoconductor immediately after the image forming operation, and the photoconductor is stopped by the reverse rotation. During that time, the rotation of the drive motor is controlled so that it rotates forward for a certain period of time.

Further, in the photoconductor drive device of the present invention (claim 2), the control means controls the rotation time of the reverse rotation ON time, the forward rotation ON time after the reverse rotation, or both of them to control the rotation of the drive motor. Optimal control is executed for each drive motor by changing each type.

Further, in the photoconductor drive device of the present invention (claim 3), the control means executes the discrimination of the motor by reversing the logic of the state detection signal of the drive motor, and the discrimination by other hardware. Eliminate means.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing the configuration of an image forming apparatus using a counter type photoconductor cleaning apparatus according to the present invention. In the figure, 101 is a photosensitive drum on which an electrostatic latent image is formed, 102 is a charging roller for uniformly charging the photosensitive drum 101, 103 is image light, and 104 is toner on the electrostatic latent image on the photosensitive drum 101. A developing device 105 for adhering the toner image, a registration roller 105 for conveying the recording paper at a timing with the toner image formed on the photosensitive drum 101, and a transfer roller 106 for transferring the toner image formed on the photosensitive drum 101 to the recording paper. A transfer belt 107 for cleaning is a cleaning device for removing and collecting the residual toner after the transfer of the photosensitive drum 101. The cleaning device 107 includes a cleaning blade 108 that comes into contact with the photosensitive drum 101 in a counter manner, and an inlet seal 109 that has a film shape to prevent scattering of collected toner in the device and contacts the photosensitive drum 101. Is provided.

Further, as a photoconductor driving device for rotatively driving the photoconductor drum 101, a drive motor 110 as a drive source thereof and a timing at which the rotation output of the drive motor 110 is provided on the shaft of the photoconductor drum 101. Pulley 111
A drive system is constituted by a timing belt 112 and the like for transmission to the. Further, a drive control system of a motor driver 113 that controls the drive of the drive motor 110 and a control unit 114 that controls the entire apparatus is provided. The drive system is not limited to this as long as it can rotate the photosensitive drum 101 at a predetermined rotation speed, and is usually employed in an image forming apparatus such as a copying machine or a laser printer. A drive system in which the photoconductor drum 101 is directly connected by the drive motor 110 and a direct drive system of a motor, or a gear drive system in which the rotational force of the drive motor 110 is transmitted to a gear on the axis of the photoconductor drum 101 may be used.

The basic operation of the image forming apparatus configured as described above will be described. The surface of the photosensitive drum 101,
A DC voltage is supplied from a power pack (not shown) to the charging roller 102 in contact with the photosensitive drum 101 to uniformly charge the charging roller 102 to a high potential. Immediately after that, when the surface of the photosensitive drum 101 is irradiated with the image light 103 by the exposure means, the potential of the irradiated portion decreases. Since the image light 103 has a light amount distribution corresponding to black / white of the image, the potential distribution corresponding to the recorded image, that is, an electrostatic latent image is formed on the surface of the photosensitive drum 101 by the irradiation of the image light.

After that, when the portion on which the electrostatic latent image is formed passes through the developing device 104, toner adheres according to the level of the potential, and a toner image is formed by visualizing the electrostatic latent image. . The recording paper is conveyed by the registration roller 105 to the portion where the toner image is formed at a predetermined timing, and overlaps with the toner image. After this toner image is transferred onto the recording paper by the transfer belt 106, the recording paper is transferred onto the photosensitive drum 1.
Separated from 01. The separated recording paper is conveyed through a conveyance path, thermally fixed by a fixing unit (not shown), and then ejected to the outside of the machine. After the transfer process is completed, the surface of the photosensitive drum 101 is cleaned by the cleaning device 1.
The cleaning process is performed by 07, and the residual charge is erased by the charge removing unit to prepare for the next image forming process.

FIG. 2 is a flow chart showing the control procedure of the photoconductor drive device according to the present invention. In the figure, when the copy process is started, first, a predetermined copy operation (JO
B) is executed (S201). When this JOB ends, WAIT1 is set for a certain time (S202), and a reverse rotation signal is output to the drive motor 110 that drives the photosensitive drum 101 (S203). Then, the reverse rotation of WAIT3 is executed for a fixed time (S204), the reverse rotation signal is stopped, and at the same time, the normal rotation signal is sent out (S205). This normal rotation is performed WAIT4 for a fixed time (S206), and the normal rotation signal is stopped (S207).

The above control will be further described with reference to FIGS. 3 and 4. As shown in b of FIG. 3, the time change of the rotation speed of the photoconductor drum 101 in the above control means that the reverse rotation is braked after the reverse rotation signal is stopped. The drum 101 suddenly decreases its reverse rotation speed and stops. In this way, the drive motor 11
By controlling 0, the relationship between the photosensitive drum 101 and the ON time of the reverse rotation signal is as shown in b of FIG.
That is, the reverse rotation distance of the photosensitive drum 101 is set to X1 to X.
In order to keep it within 2, the ON time of the reverse rotation signal should be controlled during T2. Therefore, it is not necessary to perform high-speed and highly accurate rotation control.

In the above control, when the WAIT1 time is 0 or small, a reverse rotation signal may be sent before the normal rotation of the photosensitive drum 101 is stopped. Further, after the reverse rotation is stopped, there may be some time before the output of the normal rotation signal, that is, between WAIT3 and WAIT4. Further, the control unit 114 that outputs a rotation signal for normal rotation / reverse rotation is generally incorporated in the control system of the image forming apparatus, but is included in the control unit (motor driver 113) of the drive motor. It may be.

By the way, when the control unit 114 for controlling the same drive motor 110 via the motor driver 113 controls the drive motors 110 having different characteristics, due to the difference in the torque generated when the drive motor 110 rises,
The rising acceleration when the photosensitive drum 101 rotates in the reverse direction is different. That is, the inclination of FIG. 3-c changes, and the inclination and the position of FIGS. 4-a and b change, so that the drive motor 1
Control time of 10 (WAIT2 or WAIT3 or W
It is extremely difficult to keep the reverse rotation distance of the photoconductor within X1 to X2 while keeping AIT4) the same. Therefore, in the present invention, the times of WAIT 2 to 4 are optimally changed and controlled according to the type (characteristic) of the drive motor 110.

Further, in general, the drive motor 110 is provided with the operation state of the drive motor 110 by the control unit 11 of the image forming apparatus.
There is a state detection signal to inform the 4th. The control unit 114 detects this state detection signal and executes various controls.
In the present invention, the drive motor 1 is utilized by utilizing this state detection signal.
The 10 types are determined.

In this embodiment, a lock signal is used as a state detection signal for the drive motor 110. The drive motor 110 starts rotating when the signal TRG for controlling ON / OFF of the rotation of the drive motor becomes L as shown in FIG. 5, for example. When the rotation of the drive motor 110 reaches a predetermined number of rotations, the drive motor 110 outputs the lock signal LOK to H level.
From L to L and the control unit 11 via the motor driver 113.
4 is informed that the rotational speed of the drive motor 110 has risen to a predetermined level. Further, when the load on the output shaft of the drive motor 110 is abnormally high and the rotation speed does not reach the normal rotation speed, or when the drive motor 110 is broken and does not rotate, the LOK signal does not become L, Control unit 114
Can detect that the rotation of the drive motor 110 is abnormal.

Here, the types of the drive motor 110 are A and B.
In the present embodiment, the drive motor A performs the same operation as the drive motor of the above-mentioned conventional example, and LOK = L when the rotational speed is normal as shown in FIG. 5, and L otherwise.
OK = H. However, as shown in FIG. 6, the drive motor B has LOK = H when the rotation speed is normal, and LOK = L otherwise.

As a result, the control unit 114 executes different control depending on the type of the drive motor 110 after the power is turned on.
At least 1 before executing processing with different parameters
When the LOK signal is detected and LOK = H, the motor A,
When LOK = L, the drive motor B can be detected. Further, in the state detection after the drive motor 110 is started, it can be known that the LOK signal is not inverted as compared with the state before the drive motor 110 is rotated.

FIG. 7 is a flow chart showing the above control processing. In the figure, the power is turned on (S701)
First, it is determined whether or not LOK = L (S70).
2). If it is determined here that LOK = L, the parameters for the drive motor B are set (S703). On the other hand, when it is determined in step S702 that LOK is not L, the parameters of the drive motor A are set (S704).

Further, in this embodiment, since only the lock signal is used as the state detection signal of the drive motor 110, only two kinds of drive motors 110 can be discriminated. However, when there are a plurality of state detection signals, the number of the signals is n. Book, 2
It is of course possible to discriminate the n-th power type drive motor 110.

[0032]

As described above, according to the photoconductor driving device of the present invention (claim 1), the control means outputs the rotation signal in the direction opposite to the rotation of the photoconductor immediately after the image forming operation is completed. Since the rotation of the drive motor is controlled so as to rotate forward for a certain period of time while the photoconductor stops due to the reverse rotation, the photoconductor is controlled even when the time accuracy of the drive motor ON / OFF control is low. It is possible to perform a minute reverse rotation of the with high position accuracy.

According to the photoconductor driving device of the present invention (claim 2), the control means drives the rotation time of the reverse rotation ON time, the forward rotation ON time after the reverse rotation, or both of them. Since the optimum control is executed for each drive motor by changing it for each type of motor, the control of the drive motor having a plurality of characteristics can be realized under the optimum condition by one control means. The change can be eliminated and the economy can be improved.

Further, according to the photoconductor drive device of the present invention (claim 3), the control means reverses the logic of the drive motor state detection signal to execute the determination of the start motor, and the other hardware. In the case where a plurality of drive motors are prepared in order to eliminate the need for a discriminating means, the discrimination can be made even if the signal lines and terminals for discrimination are unnecessary, and moreover, there is no setting error for each drive motor. It can be eliminated and the economy and workability can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an image forming apparatus using a counter type photoconductor cleaning apparatus according to the present invention.

FIG. 2 is a flowchart showing a control procedure of a photosensitive member driving device according to the present invention.

FIG. 3 is a diagram showing a transition of rotation speed control of a photosensitive drum.

FIG. 4 is a graph showing the relationship between the reverse rotation distance of the photosensitive drum and the drive motor reverse rotation delivery time.

5 is a timing chart showing a rotation control characteristic of a drive motor A. FIG.

FIG. 6 is a timing chart showing a rotation control characteristic of a drive motor B.

FIG. 7 is a flowchart showing a control process corresponding to a plurality of types of drive motors according to the present invention.

FIG. 8 is a flowchart showing a control process of a conventional photoconductor driving device.

[Explanation of symbols]

 101 photoconductor drum 110 drive motor 113 motor driver 114 controller

Claims (3)

[Claims] 1. A photoconductor driving device for controlling the rotation of a photoconductor carrying an image by a drive motor, wherein a rotation signal in the opposite direction to the rotation of the photoconductor immediately after the completion of the image forming operation is given, and by the reverse rotation. 2. A photoconductor drive device, comprising: a control unit that controls the rotation of the drive motor so that the photoconductor further rotates forward for a certain period of time before the photoconductor stops. 2. The control means changes the rotation time of the reverse rotation ON time, the normal rotation ON time after the reverse rotation, or both, for each type of drive motor. The photoreceptor driving device described. 3. The photoconductor driving device according to claim 1, wherein the control means executes the discrimination of the drive motor by reversing the logic of the state detection signal of the drive motor.