JPH03170988A - Cleaning device - Google Patents

Abstract

PURPOSE:To efficiently eliminate a toner by making a press-contacting angle between a blade and a photosensitive drum small by a blade press-contacting angle adjusting means. CONSTITUTION:A working piece 43 is drawn into a body of a solenoid 42, and a turning arm 45 turns counterclockwise. Accordingly, a shaft rod 34a of a supporting part 34 moves to an end part of a photosensitive drum 20 side of a slot 37. As a result, a press-contacting angle alpha of a blade 35 and the photosensitive drum 20 becomes small, and a distance between the blade 35 and the photosensitive drum 20 becomes small. In such a way, the toner adhering to the downstream side face of the blade 35 is scraped off efficiency by the rotating photosensitive drum 20, and adheres onto the photosensitive drum 20. In such a way, the toner adhering to the downstream side face of the blade 35 can be eliminated efficiently.

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. [Prior Art] In image forming apparatuses such as copying machines and laser printers,
An electrostatic latent image is formed on a photoreceptor drum that rotates at -1, 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 part having a rotation center parallel to the center of the photoreceptor drum, a blade whose base is supported by the support part and protrudes toward the photoreceptor drum, and a blade that is connected to the support part. It is known that the blade is provided with a blade approaching/disengaging means for rotating the blade about the photoreceptor drum to move it toward and away from the photoreceptor drum. The blade contact/separation means mainly consists of a weight and a solenoid, and the blade is brought into pressure contact with the photoreceptor drum by the weight, and the blade can be separated from the photoreceptor drum by the action of the solenoid. There is. In such a cleaning device, the toner on the photoreceptor drum is
It is wiped off by a blade that is pressed against the photoreceptor drum. Further, when the image forming apparatus stops operating, the blade is removed from the photoreceptor drum by actuation of a solenoid 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 removed from the photoreceptor drum, toner attached to the tip of the blade tends to flow around to the downstream side of the blade. Further, when a blade having 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 moved to the downstream side of the blade adheres to the static 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 a double image is formed, tends to occur. An object of the present invention is to provide a cleaning device that is unlikely to cause offset.

(!I!Means for solving the problem) A cleaning device of the present invention is for cleaning toner on a photoconductor drum in an image forming apparatus that forms an image using a rotating photoconductor drum. .

This cleaning device includes a blade that presses against the surface of the photoreceptor drum, and a blade pressure contact angle adjusting means for adjusting the pressure contact angle of the blade with respect to the photoreceptor drum.

[Effect]

In the cleaning device of the present invention, toner on the photosensitive drum is removed by a blade.

In such a cleaning device, when removing toner adhering to the downstream side surface of the blade, the blade contact angle adjusting means reduces the contact angle between the blade and the photoreceptor drum. This increases the contact area between the downstream side of the blade and the surface of the photoreceptor drum, and the toner adhering to the downstream side of the blade is efficiently scraped off onto the rotating photoreceptor drum and removed. Therefore, even if toner flows around to the downstream side of the blade and adheres to the downstream side of the blade, the toner is efficiently removed, and offset is less likely to occur in the cleaning device of the present invention. [Embodiment] Figure 3 shows an example of a copying machine that employs 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 l3 is arranged on the document table l2 so as to be openable and closable. A paper feed force set I-14.15 is removably attached to the right side of the copying machine main body 11 in the figure. A paper discharge tray 18 from which copied sheets are discharged is mounted on the left side of the copying machine main body 1l in the figure. Inside the copying machine main body l1, an exposure device 19 for reading originals is provided at the top. This exposure device 19 includes a light source. It has been criticized by Miller and others. Further, a photosensitive drum 20 on which an electrostatic latent image is formed is arranged in the center of the copying machine body 1. Photosensitive drum 20
Around the main charging device 2l that charges the photoreceptor drum 20 to a predetermined charge, a developing device 22 that develops the electrostatic latent image,
A transfer device 23 that transfers a toner image onto a sheet of paper, a paper separation device 24 that separates the sheet from the photoreceptor drum 20, a cleaning device 25 that removes residual toner on the photoreceptor drum 20, and a toner imager that removes the toner image from the photoreceptor drum 20. A static elimination lamp 26 is arranged to remove the latent image. Paper cassette}
14.15 and the image forming section constituted by the photoreceptor drum 20, etc., and downstream of the image forming section,
A paper feed conveyance path 27 and a paper discharge conveyance path 28 are provided for conveying paper, respectively. Paper discharge conveyance path 28 and paper tray 1
A fixing device 30 for fixing the transferred image on the paper that has been conveyed is arranged between the paper and the paper. The cleaning device 25 includes a cleaner 31 for removing toner on the photoreceptor drum 20, a screw conveyor 32 for discharging the toner removed by the cleaner 31 to the outside, and a casing 33 for housing these. It has FIG. 1 shows details of the cleaner 31. In the figure,
The cleaner 3l mainly includes a support part 34 and a blade 35.
and an arm 36. The support portion 34 is a prismatic member extending parallel to the rotation axis of the photoreceptor drum 20, and has shaft rods 34a at both ends. And the support part 34
is rotatably attached to the casing 33 by a center rod 34a. There is one point M on the casing 33 in Figure 1.
As shown by the line, a long hole 37 into which the shaft rod 34a fits is formed. The elongated hole 37 is formed in an arc shape approximately centered on the tip of the blade 35, and is disposed such that its upper end is close to the photoreceptor drum 20.

The blade 35 protrudes from the support portion 34 toward the photoreceptor drums 1 and 20. The blade 35 is made of a flexible material such as urethane rubber. blade 35
is attached to the lower part of the blade holder 38.

The blade holder 38 is a generally L-shaped member, and is rotatably attached to the support member 39 by a pin 40. The support member 39 is fixed to the lower surface of the stone in the figure of the support part 34. One end of the arm 36 is fixed to the top surface of the support section 34. The arm 36 is bent and extends substantially horizontally to the left in the figure. A weight 41 is attached to the lower surface of the arm 36.
is installed. A solenoid 42 is arranged above the cleaner 31. The solenoid 42 has an actuation piece 43 that protrudes to the lower right in the figure. The tip of the operating piece 43 is provided with a pin 44 that protrudes toward the back of the figure. A rotating arm 45 is arranged between the solenoid 42 and the cleaner 3l. The rotating arm 45 is a dogleg-shaped member, and is attached to be rotatable about a fulcrum 46. A fulcrum 46 is provided at each end of the rotating arm 45.
Grooves 47, 47 extending to the sides are formed. In the rotating arm 45, the pin 44 of the actuating piece 43 is fitted into the groove 47 on the side of the solenoid 42, and the shaft rod 3 is fitted into the groove 47 on the side of the support part 34.
Each time 4a is fitted, the support portion 34 and the actuating piece 43 are connected. Further, a spring 4 is attached to the lower end of the rotating arm 45.
One end of 8 is attached. The other end of this spring 48 is attached to the upper part of the casing 31. As a result, the moving arm 45 is always biased clockwise. A solenoid 49 is arranged on the left side of the cleaner 3l in the figure. The solenoid 49 has an operating piece 5 that projects downward.
It has 0. This actuating piece 50 has a bottle 51 that protrudes toward the back of the figure. An operating arm 52 is disposed between the solenoid 49 and the tip of the arm 36 of the cleaner 3l. This working arm 52 is attached so as to be rotatable about a fulcrum 53. A groove 54 extending toward the fulcrum 53 is formed at one end of the working arm 52.
The bottle 51 of the actuating piece 50 is fitted into the hole 4.

Thereby, the operating piece 50 and the operating arm 52 are connected. The tip of the working arm 52 on the cleaner 31 side is connected to the arm 3.
It is located below 6. In addition, the working arm 5
One end of a spring 55 is attached to the arm 36 side portion of No. 2. The other end of the spring 55 is fixed to the upper part of the casing 33. As a result, the working arm 52 is always biased counterclockwise. Next, the effects of the above embodiment will be explained.

In the copying machine main body 1l, an image read by an exposure device 19 is formed as an electrostatic latent image on a photosensitive drum 20. This electrostatic latent image is developed by the developing device 22 to become a toner image. On the other hand, paper is conveyed from one of the paper feed cassettes 14 and 15 to the photosensitive drum 20 via the paper feed conveyance path 27. The toner image on the photosensitive drum 20 is transferred by the transfer device 23 onto the transported paper. The paper onto which the toner image has been transferred is separated from the photoreceptor drum 20 by the paper heat separation device 24 and conveyed to the fixing device 30 via the paper discharge conveyance path 28, where the transferred toner image is fixed. The paper with the image fixed is placed in a fixing device of 1 t.
30 to the rJF paper tray 18. As a result, paper on which a predetermined image is formed can be obtained. After the toner image is transferred by the transfer device 23, the photosensitive drum 2
The toner remaining on the photoreceptor drum 20 moves to the cleaning device 25 as the photosensitive drum 20 rotates, and is removed there.

Next, the toner removal operation by the cleaning device 25 will be explained. During normal copy operation, the solenoid 42
is in the OFF state. In this state, the rotating arm 45 is biased clockwise by the spring 48, and the pivot arm 45 is biased clockwise by the spring 48.
4a is located at the lower end of the long hole 37 of the casing 33. Further, the solenoid 49 is in an ON state. In this state, the operating piece 50 of the solenoid 49 is drawn into the main body of the solenoid 49, as shown in FIG.
Therefore, the end of the working arm 52 on the cleaner 31 side is located at the first
As shown in the figure, it is in a state where it does not come into contact with the lower surface of the arm 36. This dead fruit arm 36 biases the support part 34 counterclockwise due to the weight of the weight 41. As a result, the blade 35 comes into pressure contact with the photoreceptor drum 20. The toner adhering to the photosensitive drum 20 is then wiped off by the blade 35. The wiped toner falls onto the screw conveyor 32 due to its own weight, and
It is discharged outside as waste toner.

When the copy operation stops, the solenoid 49 turns OFF.
It becomes F. As a result, the operating arm 52 is rotated counterclockwise by the biasing force of the spring 55 and presses the arm 36 upward. Therefore, the support part 34 rotates clockwise,
The blade 35 separates from the photoreceptor drum 20. At this time, the toner accumulated on the tip of the blade 35 is removed from the blade 35.
5 and may adhere to the downstream side of the blade 35. Such toner is removed as follows.

For example, in a copy preparation operation, first, the solenoid 49 is turned on to rotate the sakukawa arm 52 clockwise, thereby bringing the blade 35 into pressure contact with the photosensitive drum 20 . That is, the cleaner 31 is set to a normal cleaning state. Next, the photosensitive drum 20 is rotated and its surface is charged. Then solenoid 4
Turn 2 ON. When the actuating member 43 is moved, the operating piece 43 is drawn into the main body of the solenoid 42, and the rotating arm 45 rotates counterclockwise. Accordingly, the shaft rod 34a of the support portion 34 moves to the end of the elongated hole 37 on the photosensitive drum 20 side. As a result, as shown in FIG.
0 (see FIG. 1) becomes smaller, and the distance between the blade 35 and the photosensitive drum 20 becomes smaller. As a result, the toner adhering to the downstream side surface of the blade 35 is efficiently scraped off by the rotating photoreceptor drum 20 and adheres to the photoreceptor drum 20. The toner adhering to the photoreceptor drum 20 is moved again to the upstream side of the blade 35 by the rotation of the photoreceptor drum 20, and is wiped off by the blade 35. In this manner, in this embodiment, toner adhering to the downstream side surface of the blade 35 can be efficiently removed. Therefore, in this embodiment, offset is less likely to occur. In the above description, the solenoid 42 is activated after the photoreceptor drum 20 is rotated so that the contact angle between the blade 35 and the photoreceptor drum 20 becomes small, but the opposite may be used. That is, first, the contact angle between the blade 35 and the photoreceptor drum 20 is made small, and then the contact angle between the blade 35 and the photoreceptor drum 20 is reduced.
You can also rotate 0. [Other Embodiments] (a) In the embodiment described above, the blade 35 is biased toward the downstream side of the photoreceptor drum 20 so that the photoreceptor drum 20
How to remove the toner on the top (so-called counter one-way method)
However, the invention is not limited to this. 1. That is, the present invention may be adopted as a method (so-called trail method) in which toner is removed from the photoreceptor drum by biasing the blade toward the upstream side of the photoreceptor drum. In this case, in order to remove toner adhering to the tip end surface of the blade, the pressure contact angle between the blade and the photosensitive drum is controlled to be large.

(c) In the above embodiment, the blade 35 and the photosensitive drum 2
Although the solenoid 42 is used as a means for adjusting the pressure contact angle with respect to 0, other means such as a stepping motor may be used.

(C) In the embodiment described above, the blade 35 is pressed against the photosensitive drum 20 using the weight 4L, but the present invention is not limited to this. For example, a solenoid, a spring, a cam, etc. may be used instead of the 4L weight. [Effects of the Invention] According to the present invention, toner adhering to the blade can be efficiently adhered to the photoreceptor drum side and removed by the blade pressure contact angle adjusting means. Therefore, according to the present invention,
Offset is less likely to occur.

[Brief explanation of the drawing]

FIG. 1 is a front partial view of an embodiment of the present invention, FIG. 2 is a schematic partial view showing the operation of the embodiment, and FIG. 3 is a schematic vertical sectional view of a copying machine employing the embodiment. 20... Photoreceptor drum, 34... Support part, 35...
-Blade, 42... Solenoid, 45... Rotating arm.

Claims (1)

[Claims] (1) In an image forming apparatus that forms images using a rotating photoreceptor drum, a cleaning device for cleaning toner on the photoreceptor drum, the blade being in pressure contact with the surface of the photoreceptor drum; A cleaning device comprising: a blade pressure contact angle adjusting means for adjusting a pressure contact angle of the blade with respect to the photoreceptor drum.