JPH03168679A - Cleaning device - Google Patents

Abstract

PURPOSE:To suppress the generation of offsetting by providing a means to bring a cleaning blade into a pressurized contact with the photosensitive body and a means to travel it in the direction of projection, separating it from the photosensitive body drum. CONSTITUTION:During a copying action, a solenoid (S)43 is turned ON, an acting piece 44 is pulled in, a leading tip of a blade (B)36 is abutted to the surface of photosensitive body drum (D)20 through a first arm 33. A supporting part 32 is energized with a weight 42 by a second arm 34, B36 is brought to a pressurized contact on D20, and toner stuck to D20 is wiped off. When the copying action is stopped, S43 is turned off, a rotating arm 46 is rotated in the direction X by a spring 49, D20 is separated from B36, the arm 34 is abutted to the stopper 45 and stopped by the weight 42. When the copying action is restarted, B36 is brought into a pressurized contact in a more down stream side than the cleaning position of D20. Thus, it is difficult for the toner to be rotated to the down stream side of B36, any rotated toner is wiped off with a resin film 39, and offsetting is made difficult to be generated.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a cleaning device, particularly an image forming apparatus that forms an image using a rotating photoreceptor drum, for cleaning toner on the photoreceptor drum. Regarding cleaning equipment for [Prior Art] In image forming devices such as copying machines and laser printers,
Generally, an electrostatic latent image is formed on a rotating photoreceptor drum, the latent image is developed with toner, and the resulting toner image is transferred to transfer paper. The toner remaining on the photoreceptor drum after the transfer process is removed by a cleaning device.

A conventional cleaning device includes, for example, a support portion having a rotation center parallel to the center of the photoreceptor drum, a blade whose base is supported by the support portion and protrudes toward the photoreceptor drum, and the blade connected to the support portion. It is known that the blade is provided with a blade approaching/disengaging means for rotating the blade about the center to bring it close to and away from the photosensitive drum. The blade contact/separation means is mainly composed of a weight and a solenoid, and the weight of the weight presses the blade against the photoreceptor drum, and the action of the solenoid makes it possible to separate the blade from the photoreceptor drum. ing. In such a cleaning device, toner remaining on the photoreceptor drum is removed by a blade that is pressed against the photoreceptor drum. Further, when the operation of the image forming device is stopped, the blade is removed from the photoreceptor drum by actuation of a solenoid in order to prevent deformation of the blade and deterioration of the photoreceptor. [Problems to be Solved by the Invention] In the conventional cleaning device described above, when the blade is detached from the photoreceptor drum, toner attached to the tip of the blade tends to flow around to the downstream side of the blade. Furthermore, when a blade with toner attached to its tip is brought into pressure contact with a photoreceptor drum, the rotation of the photoreceptor drum may cause the toner to move downstream of the blade. In this way, the toner that has entered the downstream side of the blade adheres to the electrostatic latent image on the photoreceptor drum again and prevents charge removal from the electrostatic latent image. As a result, when a new electrostatic latent image is formed on the photoreceptor drum, the previous latent image remains, and so-called offset, in which double images are copied, tends to occur.

An object of the present invention is to provide a cleaning device that is unlikely to cause offset.

[Means to solve the problem]

The cleaning device of the present invention is for cleaning toner on a photosensitive drum in an image forming device that forms an image using a rotating photosensitive drum.
This cleaning device includes: a support portion having a rotation center line parallel to a center line of the photoreceptor drum; a blade having a base supported by the support portion and protruding toward the photoreceptor drum side for cleaning the photoreceptor drum; A blade pressure contact means for pressing the blade onto the photoreceptor drum by urging the blade toward the downstream side of the photoreceptor drum; It is equipped with a blade contact/separation means. [Function] In the cleaning device of the present invention, the blade is rotatably supported by the support portion. This blade is rotated toward the photoreceptor drum by the blade pressure contact means and is pressed onto the photoreceptor drum. As a result, the toner on the photoreceptor drum is removed. Further, the blade is moved toward the support portion by the blade contact/separation means and is separated from the photoreceptor drum. According to this operation of detaching the blade from the photoreceptor drum, toner attached to the tip of the blade is difficult to wrap around to the downstream side of the blade. As a result, offsets are less likely to occur. [Embodiment] Fig. 3 shows an example of a copying machine employing an embodiment of the present invention. In FIG. 3, on the top surface of the copying machine main body l1, there is a document table l.
2 is fixed, and a document presser 13 is arranged on the document table 12 so as to be openable and closable. On the right side of the copying machine main body 11 in the figure, a paper feed force set 14, 15 is detachably attached. A discharge tray 18 is installed on the left side of the copying machine main body 11 in the figure, from which copied sheets are discharged. Inside the copying machine main body 1l, an exposure device 19 for reading originals is provided at the top. This exposure device 19 includes a light source. It is constructed from ξler etc. Further, a photosensitive drum 20 on which an electrostatic latent image is formed is arranged in the center of the copying machine main body 11. Photosensitive drum 20
Around the main charging device 21 that charges the photoreceptor drum 20 to a predetermined charge, a developing device 22 that develops the electrostatic latent image,
A transfer device 23 for transferring a toner image onto paper; a paper separation device 24 for separating the paper from the photoreceptor drum 20;
, a cleaning device W. for removing residual toner on the photoreceptor drum 20; 25, and a static elimination lamp 26 for removing the electrostatic latent image on the photosensitive drum 2'0. Between the paper feed cassette 14, 15 and the image forming section which is controlled by the photoreceptor drum 20, etc., and on the downstream side of the bottom of the image form, there are a paper feed conveyance path 27 for conveying paper and a paper discharge conveyance path, respectively. A passage 28 is provided. A fixing device 30 that fixes the transferred image on the transported paper is disposed between the wandering transport path 28 and the paper discharge tray 18.

The cleaning device 25 includes a cleaner 31 for removing toner on the photoreceptor drum 20, a screw conveyor 50 for discharging toner removed by the cleaner 31, and a casing 51 for housing these. have.

Figure 1 shows the details of the cleaner 3l. In the figure,
The cleaner 31 mainly includes a support section 32 and a first arm 3.
3 and a second arm 34.

The support portion 32 is a prismatic member extending parallel to the rotation axis of the photoreceptor drum 20 that rotates clockwise, and has shaft rods 32a at both ends. The shaft rods 32a are each rotatably attached to the casing 51 (FIG. 3). The first arm 33 is attached to the upper right surface of the support portion 32 in the figure, and its lower end protrudes toward the photosensitive drum 20 side. The first arm 33 has a long hole 33a that is long in a direction perpendicular to the longitudinal direction of the support section 32. The first arm 33 is attached to the support portion 32 so as to be vertically movable by a pin 33b passing through the length 7L33a.

A blade 36 is attached to the lower end of the first arm 33 and is pressed onto the photosensitive drum 20 via a blade holder 35 . The blade 36 is made of a flexible material such as urethane rubber. Note that the blade holder 35 is rotatably attached to the first arm 3 by being fitted onto a pin 37.
It is supported by 3. A toner scattering prevention cover 38 whose base is fixed to the earthen wall of the casing 51 is arranged above the blade 36 . A resin sheet 39 made of, for example, polyester resin is attached to the lower end of the scattering prevention cover 38. The lower end of the resin sheet 39 is connected to the blade 36.
It is in elastic contact with the downstream side of the tip. Further, on the upstream side of the blade 36, a lower scattering prevention cover 40 is arranged so as to be in contact with the photosensitive drum 20. The upper part of the seventeenth arm 33 is bent in a direction away from the support part 32. A flat plate-shaped member 41 is attached to the upper end of the first arm 33 and protrudes toward the lower left in the figure.
The member 41 has a pin 41a that projects toward the front side in the figure. The second arm 34 has one end fixed to the lower left surface of the support section 32 in the figure. The second arm 34 is bent and extends substantially horizontally to the left in the figure. And the second arm 3
A stopper 45 is disposed below the other end of the casing 4 and projects horizontally from the casing 5l. A weight 42 is attached to the lower surface of the second arm 34. Also, the second
A solenoid 43 is attached to the upper surface of the arm 34. The solenoid 43 has an operating piece 4 that protrudes to the right side in the figure.
It has 4. The tip of the actuating piece 44 has a pin 44a that protrudes toward the back of the figure. The operating piece 44 of the solenoid 43 and the member 4l of the first arm 33 are connected to the rotating arm 46.
are connected by. The rotating arm 46 is a generally L-shaped member, and is rotatable by a fulcrum 47 provided at the center. Grooves 48 and 48 extending in the direction of the fulcrum 47 are formed at both ends of the rotating arm 46, respectively. The rotating arm 46 is connected to the member 41 by fitting the pin 41a of the member 41 into the groove 48 on the member 4l side and fitting the pin 44a of the actuating piece 44 into the groove 48 on the actuating piece 44 side. 44 are connected. The rotating arm 46 includes a member 4l.
One end of a spring 49 is attached near the .
The other end of the spring 49 is fixed to the casing 5l, and the spring 49 always urges the rotating arm 46 in the X direction. Next, the effects of the above embodiment will be explained.

During the copy operation, the solenoid 43 is in an on state.
In this state, the operating piece 44 of the solenoid 43 is retracted toward the main body of the solenoid 43, as shown in FIG. Therefore, the first arm 33 moves to the lowest position, and the blade 36 protrudes toward the photosensitive drum 20 side. The tip of the blade 36 is in contact with the surface of the photoreceptor drum 20. Further, the 27th arm 34 biases the support portion 32 in the counterclockwise direction by the weight of the weight 42. As a result, the blade 36 is brought into pressure contact with the photoreceptor drum 20. In this state, the toner adhering to the electrostatic latent image formed on the photoreceptor drum 20 is wiped off by the blade 36. The wiped toner falls onto the screw conveyor 50 due to its own weight and is discharged to the outside as waste toner. When the copy operation is stopped, the solenoid 43 is turned off. As a result, the rotating arm 46 rotates in the X direction by the biasing force of the spring 49 and pulls the seventeenth arm 33 upward, so that the blade 36 protrudes less and separates from the photoreceptor drum 20. At the same time, the cleaner 3l begins to rotate counterclockwise around the support portion 32 due to the weight of the weight 42, but this continues until the second arm 34 comes into contact with the stopper 45. When the copying operation is restarted, the solenoid 43 is turned on again, and the rotating arm 46 rotates in the reverse X direction against the biasing force of the spring 49. As a result, the first arm 33 moves downward, and the blade 36 comes into pressure contact with the photosensitive drum 20 again. Note that while the blade 36 is detached, the support portion 3
2 has been rotated slightly counterclockwise. For this reason,
The blade 36 comes into pressure contact with the photoreceptor drum 20 from the downstream side of the cleaning position of the photoreceptor drum 20. Therefore, the toner accumulated at the current cleaning position is difficult to go around to the downstream side of the blade 36 when the blade 36 is pressed against the blade 36.

As described above, in this embodiment, the blade 36 moves in its protruding direction and separates from the photoreceptor drum 20. That is, the blade 36 separates toward the downstream side of the photoreceptor drum 20. Further, the blade 36 contacts the photosensitive drum 20 from the downstream side of the cleaning position. Therefore, it is difficult for toner to get around to the downstream side of the blade 36.
Therefore, in this embodiment, offset is less likely to occur. Even if the toner gets around to the downstream side of the blade 36, in this embodiment, this toner can be wiped off by the resin film 39. Here, suppose that when the blade 36 is separated from the photosensitive drum 20, the toner T wraps around to the downstream side of the blade 36 as shown in FIG. 2A. However, in this embodiment, as the blade 36 is detached, the tip of the resin sheet 39 is attached to the blade 3.
6 in the direction of the photoreceptor drum 20. As a result, the downstream side surface of the tip of the blade 36 is cleaned, and the second
As shown in Figure B, the toner T that has entered the downstream side of the blade 36 is wiped off upstream. Therefore, the second C
As shown in the figure, the blade 36 is again attached to the photoreceptor drum 20.
When the toner T is pressed against the blade 36, the toner T flows to the downstream side of the blade 36
wraparound is better prevented. [Other Embodiments] In the embodiments described above, the blade 36 is configured to be pressed against the photosensitive drum 20 by the weight 42, but the present invention is not limited to this. Instead of the weight 42, for example, a spring or a solenoid may be used. [Effects of the Invention] According to the present invention, the blade for cleaning the photoreceptor drum can be moved toward and away from the photoreceptor drum by moving in the direction in which it protrudes. For this reason,
In the present invention, it is difficult for toner to wrap around the downstream side of the blade, and offset is difficult to occur.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an embodiment of the present invention, FIGS. 2A, 2B, and 2C are diagrams showing the operating states of the embodiment, and FIG. 3 is a copying machine employing the embodiment. FIG. 20... Photoreceptor drum, 32... Support part, 33...
・First arm, 36...blade, 42...weight,
43... Solenoid, 46... Rotating arm.

Claims (1)

[Claims] (1) In an image forming apparatus that forms an image using a rotating photoreceptor drum, a cleaning device for cleaning toner on the photoreceptor drum, the cleaning device rotating parallel to the center line of the photoreceptor drum. a support portion having a center line; a blade for cleaning the photoreceptor drum whose base is supported by the support portion and protrudes toward the photoreceptor drum; and a blade for cleaning the photoreceptor drum in the downstream direction of the photoreceptor drum. a blade pressure-contact means for bringing the blade into pressure contact with the photoreceptor drum by urging the blade toward the photoreceptor drum; and a blade contact/separator for bringing the blade into contact with and away from the photoreceptor drum by moving the blade in its protruding direction. A cleaning device comprising means and.