JPH05333748A - Cleaning method for photosensitive drum - Google Patents

Abstract

PURPOSE:To remove toner scattering at a stop process and to prevent soiling on a printing surface by bringing a blade into contact with a drum while reversely rotating the drum at a starting process and then normally rotating the drum so as to shift to a printing process. CONSTITUTION:At the starting process where printing is started after printing data is inputted, the drum 1 is reversely rotated, and after the drum 1 is reversely rotated until the clean surface of the drum comes to a position on a transfer device side far from the leading end part of the blade 2, a solenoid is turned on so as to press the blade 2 against the drum 1. In the case that the toner 3b sneaks on the back side of the blade 2 at this time, the toner is wiped off by the surface of the drum 1, and almost the toner drops, but some toner sticks to the surface of the drum and then moves to the transfer device side. The reverse rotation of the drum is stopped after reversely rotating the drum and pressing the blade 2 against the drum, and then, the drum is rotated in a forward direction. When the drum is normally rotated, the toner sticking to the surface of the drum on the transfer device side far from the blade 2 is removed by the blade 2 which comes in contact with the drum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a photosensitive drum using a blade in an electrophotographic printer.

[0002]

2. Description of the Related Art Conventionally, as a method for cleaning a photosensitive drum, there is a method in which a rubber blade is brought into contact with a part of the peripheral surface of the photosensitive drum to scrape off the toner adhering to the photosensitive drum. If the photosensitive drum is stopped while it is in contact with the drum, the quality of the photosensitive drum is deteriorated. Therefore, the blade is generally separated from the drum when the photosensitive drum is stopped. FIG. 1 is a diagram for explaining the operation of the conventional method.

However, when the blade 2 is separated from the drum 1 using, for example, a solenoid (FIG. 1 (c)),
Due to the impact, the toner 3 attached to the blade 2
There are problems such as scattering on the drum (Fig. 1 (c) 3a) or adhering toner on the back side of the blade (Fig. 1 (c) 3b), so the drum stops (Fig. 1 (b)). )rear,
After reversing the drum by a small amount to move the blade away from the drum, or while reversing, separating the blade from the drum (see FIG.
(c)), stop the reverse rotation (same as (d)), and at the time of starting after receiving the print data, bring the blade 2 into contact with the drum surface cleaned by the reverse rotation (Fig. 1 (e)), and then the drum A control method of rotating in the forward direction (FIG. 1 (f)) has been used (for example, JP-A-60-178478).

[0004]

However, according to the above-mentioned conventional method of reversing in the stopping process, the above-mentioned problem is solved, but the problem of (3) remains, so that the toner 3b sneaking around the blade at the time of start-up. Since the blade 2 presses against the drum 1, there is a problem that the printed surface appears as dirt.

The present invention has been made in order to solve the above-mentioned problem, and the blade is attached to the blade by performing the contact / separation timing of the blade, the stopping of the drum in the stopping process and the starting process, and the forward / reverse timing in a specific order. It is an object of the present invention to provide a method for cleaning a photosensitive drum using a blade capable of preventing the generation of stains on the printing surface due to the scattering and sneaking of the toner.

[0006]

In order to achieve the above object, the method for cleaning a photosensitive drum according to the present invention is terminated by separating the blade after the rotation of the drum is stopped in the exposure process, and in the starting process. Is characterized by rotating the drum in the forward direction after pressing the blade against the drum while reversing the drum.

[0007]

When the blade is separated after the drum is stopped in the stopping process, a part of the toner adhering to the blade drops downward, and a part of the toner scatters and adheres to the drum surface.
The rest remains on the blade. Part of the remaining toner wraps around around the back surface of the blade. But in the boot process,
Since the blade is pressed against the drum while reversing the drum, the toner wrapping around the back surface of the blade is wiped off by the reversing drum surface. Then, during the forward rotation of the drum, the toner attached to the surface of the drum is removed by the blade.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is a partially omitted schematic configuration diagram centering on the control system of the electrophotographic printer, in which a charging device, an exposing device, a developing device, a transferring device, which are not shown, are provided around the photosensitive drum 1.
The purifier 4 and the static eliminator according to the present invention are arranged in this order.

The purifier (cleaning unit) comprises a rubber blade 2, a swing arm 41 for holding the blade against the surface of the drum 1, and a swing arm for swinging the blade 2 to contact the drum surface. Solenoid to be released (SO
L) 42 and SO for controlling ON / OFF of the solenoid
And an L control circuit 43. The tip of the blade 2 contacts the surface of the photosensitive drum 1 behind the transfer position when the solenoid 42 is turned on, and is brought into contact with and separated from the surface of the photosensitive drum 1 when the solenoid is turned off.

Further, the drum 1 is provided with a drum drive section 5 comprising a motor 51 for rotating the motor 1 in the normal direction or the reverse direction, and a motor control circuit 52 for controlling the normal rotation / reverse rotation / stop of the motor.
Are connected. These are carried out by transmission through the gear 11.

The components from the charger to the static eliminator and the drum driving section 5 are connected to the microcomputer 6 having the CPU 62 and the storage sections 63 and 64 via the I / O interface 61, and The microcomputer 6 is connected to a receiving unit 7 that receives and inputs print data from an external device or a data processing unit that creates print data.

FIG. 3 is an operation explanatory view of the purifier according to the present invention corresponding to FIG. 1, and FIG. 4 is a flow chart for explaining the overall operation of the printer.

In the cleaning method according to the present invention, during the printing operation (S _{6 in} FIG. 4), as in the conventional method,
The drum 1 is rotated in the forward direction (normal rotation) and the solenoid is turned on.
The blade 2 is kept in the N state and is in contact with the drum 1 (FIG. 3 (a)). Then, in the stop process in which the print data is completely received or input and the print operation is started (Y in S ₇ ), first, as shown in FIG.
The rotation of the drum 1 is stopped (S ₈ ), and then the solenoid 4
2 is turned off (S ₉ ) and the blade 2 is separated from the drum 1. At this time, a part 3a of the toner 3 adhered to the blade 62 is scattered, a part of the toner 3 adheres to the surface of the drum, the remainder falls downward, and the other part 3b is the back surface of the blade. (See Figure 3 (c)).

When the print data is no longer input, the printer is in a standby state (stop state) (N in S ₁ ), print data is input again (Y in S ₁ ), and the printing operation is started. (S2 ₎ , and after the clean surface of the drum is reversed from the tip of the blade to the transfer unit side, the solenoid 42 is turned on and the blade 2
The pressed against the drum 1 (Fig. _{3 (d)) (S 3} ). At this time, if there is toner 3b sneaking around on the back surface of the blade, the toner is wiped off on the drum surface, and most of it falls (Fig. 3 (e)), but it adheres to the drum surface and is transferred to the transfer unit side. It may move to. In this way, after pressing the blade while reversing the drum (for example, after pressing the blade during the last (1/3) t of the time t when the drum reverses), the reverse rotation is stopped and the drum 1 is rotated in order. Rotate in the direction (Fig. 3 (f)) (S5 ₎ . During this rotation, the toner 3c adhering to the drum surface on the transfer unit side of the blade 2 is removed by the blade 2 in contact with the drum.

The control of the forward rotation may be the same as the control at the time of start-up in the related art, the printing operation can be performed by the normal process control, and the adhered toner on the drum surface reversed in FIG. It is not transferred to the paper in the transfer process. Following the forward rotation of FIG. 3F, the printing process is started.

[0016]

As described above, according to the method of the present invention, in the stopping process, the drum is simply stopped and the blades are separated from each other, and in the starting process, the blades are brought into contact with each other while reversing the drum. After that, I tried to rotate the drum forward and shift to the printing process,
The control is less complicated than the conventional method,
Moreover, since the toner scattered or sneaking around due to the blade separation in the stopping process is removed from the drum surface in the starting process, it is possible to effectively prevent the printing surface from being soiled.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an operation in a conventional cleaning method.

FIG. 2 is a schematic configuration diagram of an electrophotographic printer.

FIG. 3 is a diagram for explaining the operation of the method of the present invention.

FIG. 4 is a time chart of the same.

Claims (1)

[Claims] 1. In the stopping process, the blade is separated from the photosensitive drum after the rotation of the photosensitive drum is stopped,
In the start-up process, the photosensitive drum is rotated in the forward direction after pressing the blade against the photosensitive drum while rotating the photosensitive drum in the reverse direction, and then rotating the photosensitive drum in the forward direction.