JP3491486B2 - Transfer roll cleaning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an image transfer member provided in an image forming apparatus such as an electrophotographic copying machine or a laser printer, and more particularly to a cleaning device for removing the image transfer member from the transfer member. The present invention relates to an improved cleaning device for preventing a recording medium from being stained due to, for example, unfixed toner collected in one place adhering to the transfer member. 2. Description of the Related Art FIG. 4 shows a main configuration of a conventionally known image forming apparatus. The image forming apparatus shown in FIG. 1 is for a full-color image. In this full-color image forming apparatus, an image is formed as follows. First, the surface of the photosensitive drum 1 as a latent image carrier is uniformly charged by a charging roll (not shown). Subsequently, a laser scanner (not shown) driven according to the video signal
Thereby, an electrostatic latent image is formed on the photosensitive drum 1. [0003] The electrostatic latent image is developed with toner. The developing device 2 has developing devices 2a, 2b, 2c, and 2d corresponding to the colors of yellow (Y), magenta (M), black (Bk), and cyan (C), and is formed on the photosensitive drum 1. The developed electrostatic latent image is developed by any one of the developing devices to form a toner image. For example,
If the electrostatic latent image written on the photosensitive drum 1 corresponds to yellow image information, the electrostatic latent image is developed by a developing device 2a having yellow (Y) toner, and 1, a yellow toner image is formed. The above process is repeated for each color to form an unfixed toner image of each color for each rotation of the photosensitive drum 1.
The unfixed toner is superimposed on the belt-shaped intermediate transfer body 3, and the combined image is transferred to the recording medium P at a time. The intermediate transfer member 3 includes a plurality of rolls 4
The roll 4 is a backup roll, and is opposed to the secondary transfer roll 8 with the intermediate transfer member 3 interposed therebetween. The secondary transfer roll 8 for transferring the composite image to the recording medium P is separated from the intermediate transfer member 3 while the unfixed toner images of the respective colors are superimposed on the intermediate transfer member 3. After the unfixed toner images of all the colors are primarily transferred onto the intermediate transfer member 3, the intermediate transfer member 3 is pressed so as to come into contact with the intermediate transfer member 3 during the secondary transfer to the recording medium P. After the secondary transfer, the unfixed toner adhered to the secondary transfer roll 8 is scraped off by a transfer roll cleaner 9 and stored in a toner collecting container 10. Normally, all the unfixed toner image formed on the intermediate transfer member 3 is transferred to the recording medium P, and therefore, the toner image does not adhere to the secondary transfer roll 8. However, there is a case where the recording medium P smaller than the size of the unfixed toner image formed on the intermediate transfer member 3 is erroneously supplied, or the recording medium P is not supplied. The toner is removed by the transfer roll cleaner 9. The transfer roll cleaning device 9 is a blade-shaped member provided along the axial direction of the secondary transfer roll 8. The unfixed toner remaining on the intermediate transfer member 3 is cleaned by the intermediate transfer member cleaner 11. The driving directions of the photosensitive drum 1 and the intermediate transfer member 3 are indicated by arrows A and B in the figure, respectively. An example of an electrophotographic apparatus provided with this type of cleaning means is described in Japanese Patent Publication No. 5-173398. [0007] The conventional image forming apparatus has the following problems. Transfer Roll Cleaning Device 9
The toner scraped off as a result forms a toner peak 12 in the toner collection container 10. This toner mountain 1
When the value of 2 is high, the toner is re-adhered to the secondary transfer roll 8, and the cleaning effect is reduced. Also, the toner mountain 1
When the height of the transfer roll cleaner 9 is higher than the position of the transfer roll cleaner 9, the toner on the toner ridge 12 wraps around from both ends in the longitudinal direction of the transfer roll cleaner 9, and adheres to the back surface of the recording medium P and becomes dirty. There was a problem. The present invention solves the above-mentioned problems, and a transfer roll cleaning apparatus in which toner collected by being scraped off from a secondary transfer roll by a cleaning means is prevented from adhering to a recording medium, the secondary transfer roll, or the like. The purpose is to provide. [0009] In order to solve the above-mentioned problems and to achieve the object, the present invention provides a blade for peeling off toner adhered to a transfer roll, and a support plate for supporting the blade. And a driving unit that swings the support plate so that the blade operates in a direction in which the blade contacts the transfer roll at a transfer timing, and operates in a direction away from the transfer roll at a non-transfer timing. Receiving the toner separated from the transfer roll, the toner collecting container disposed below the blade and the toner accumulated in the toner collecting container can be leveled with the swing of the support plate. As described above, the present invention is characterized in that a toner mountain breaking member provided to extend to the support plate is provided. [0010] According to the above feature, the toner separated from the transfer roll by the blade drops and accumulates on the toner collecting container. On the other hand, as the support plate of the blade moves the blade toward and away from the transfer roll, the toner mountain breaking member is swung. As a result, the toner accumulated in the toner collecting container is leveled and does not peak. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a transfer roll cleaning apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a main part configuration diagram of an image forming apparatus to which the present invention is applied with a transfer roll cleaning device according to one embodiment, and the same reference numerals as in FIG. 4 indicate the same or equivalent parts. A recording medium, that is, recording paper Pa is stacked on the recording paper tray 13, and is sequentially moved between the secondary transfer roll 8 and the intermediate transfer body 3 by the feed roller 14 (secondary transfer). Position). The recording paper P is carried out of the tray 13 at a scheduled timing,
The secondary transfer roll 8 and the intermediate transfer body 3 at the secondary transfer position
Is sandwiched between. On the other hand, the unfixed toner image primarily transferred from the photosensitive drum 1 to the intermediate transfer member 3 moves to a secondary transfer position facing the conveyance path of the recording paper P with the rotation of the intermediate transfer member 3. Conveyed. On the back side of the intermediate transfer body 3 at the secondary transfer position, a backup roll 4 serving as a counter electrode of the secondary transfer roll 8 is provided. The backup roll 4 is formed by covering an insulating roll with a semiconductive conductive layer partially grounded. When a voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roll 8, the unfixed toner image carried on the intermediate transfer body 3 is electrostatically transferred to the recording paper P at the secondary transfer position. The recording paper P on which the toner image has been transferred is fed to the fixing device 15 and thermally fixed, and is output to a discharge tray (not shown). When a single-color image is formed, the unfixed toner image primarily transferred to the intermediate transfer member 3 is immediately secondarily transferred to the recording paper P, but a color image in which a plurality of color toner images are superimposed is formed. In this case, as described with reference to FIG. 4 regarding the related art, the steps of forming the toner image on the photosensitive drum 1 and primary transferring the toner image are repeated by the number of colors. The intermediate transfer member 3 on which the secondary transfer of the unfixed toner image has been completed is cleaned by the intermediate transfer member cleaner 11, and the secondary transfer roll 8 is cleaned by the transfer roll cleaner 9. The transfer roll cleaner, that is, the blade 9 is made of, for example, polyurethane rubber having a thickness of 2 mm and a length of 339 mm, and is held by a plate member (support plate 21) described later. The secondary transfer roll 8 and the intermediate transfer body cleaning device 9 are disposed so as to be able to contact and separate from the intermediate transfer body 3, respectively. When a full-color image is formed, the final color is not determined. The members 8 and 9 are separated from the intermediate transfer member 3 until the toner image is primarily transferred to the intermediate transfer member 3. Further, the transfer roll cleaning device 9 is separated from the secondary transfer roll 8 while the secondary transfer roll 8 is separated from the intermediate transfer body 3. The reason why the transfer roll cleaning device 9 is always in contact with the secondary transfer roll 8 is that it is not preferable considering the wear of the transfer roll cleaning device 9. From this viewpoint, at the time of the separation, the contact between the roll cleaning device 9 and the secondary transfer roll 8 is not necessarily completely cut off. Good. In this embodiment, further, a mountain breaking member 16 for flattening the dropped toner as indicated by reference numeral 12a is provided so that the toner dropped in the toner collecting container 10 does not rise and form the mountain 12. . Next, the configuration and operation of the secondary transfer roll 8, the transfer roll cleaning device, that is, the blade 9, and the mountain cutting member 16 will be described in detail. FIG. 1 is a side view showing a main part of a secondary transfer position, and FIG. 2 is a plan view of the same. FIG. 1 (a)
1 shows the position of the secondary transfer roll 8 at the time of the secondary transfer, and FIG. 1 and 2,
Shafts 17 and 18 projecting from both sides of the side walls 10a and 10b of the toner collecting container 10 are provided. The shaft 17,
The support plates 19 and 20 of the secondary transfer roll 8 are swingably attached to the outside of the shaft 18 so as to swing.
A support plate 21 of the blade 9 is swingably attached to the one of the projections 7 and 18 that protrudes inward. More specifically, the support plate 21 is mounted on the shaft 1 via brackets 21a and 21b formed at both ends of the support plate 21.
7 and 18. The secondary transfer roll 8 is supported on the support plates 19 and 20 by a shaft 8a. on the other hand,
The support plates 19, 20 are provided on the support plates 19, 20 respectively.
A tension spring 22 is provided for rotating 0 around the shafts 17 and 18 in the clockwise direction in the figure. Further, the support plates 19, 20 and the support plate 21 are disposed so as to be engageable with each other on the upper surfaces of the projecting portions on both sides. The blade 9 is attached to the support plate 21 by affixing or suitable bonding means. At the same time, the tip of the support plate 21 is extended and bent downward to remove the mountain breaking member 16. Make up. The mountain breaking member 16 may be a member integral with the support plate 21 or may be formed as a separate member and connected to the support plate 21 by an appropriate means such as welding or screwing. During the secondary transfer, the blade 9 is pressed against the secondary transfer roll 8, and during non-secondary transfer, the blade 9 is separated from the secondary transfer roll 8. The pressing and separating operations are performed by the movement of the cam 23. The cam 23 is a rotating shaft 2
4 and the shaft 24 is rotated by a motor (not shown). A tension spring 2 is provided at an end of the support plate 21 of the blade 9 (an end opposite to the mountain breaking member 16).
The support plate 21 is pressed against the outer periphery of the cam 23 by the tension spring 25. At the time of the secondary transfer, power is transmitted from the motor to the shaft 24 by the operation of a clutch (not shown) so that the cam 23 is at the minimum height position. When the cam 23 is at the maximum height, the support plate 21 and the support plates 19, 20
With the support plates 19, 20
Is urged clockwise in the figure by a tension spring 22, and the secondary transfer roll 8 is pressed against the intermediate transfer body 3 (FIG. 1A).
The clutch can be switched by, for example, energizing a solenoid or the like. At times other than during the secondary transfer, the shaft 24 is biased so that the cam 23 is at the maximum height position. Then, the support plate 21 is rotated counterclockwise about the shafts 17 and 18, and the support plate 21 and the support plates 19 and 19 are rotated.
20 are engaged. As a result, the support plates 19, 20
Is urged counterclockwise in the figure against the tension spring 22,
The secondary transfer roll 8 is separated from the intermediate transfer body 3 (see FIG. 1).
(B)). The operation of the cam 23 during the secondary transfer and the non-secondary transfer causes the support plate 21 to rotate the shafts 17 and 1.
It swings around 8 as shown by arrow C. As shown in FIG. 1A, at the time of the secondary transfer, the support plate 21 is in contact with the minimum height position of the cam 23, and the blade 9 and the peak breaking member 16 swing clockwise around the shafts 17 and 18 in the drawing. Have been. On the other hand, as shown in FIG. 1B, at the time of non-secondary transfer, the support plate 21 is in contact with the maximum height position of the cam 23, and the blade 9 and the mountain breaking member 16 are swung counterclockwise in the figure. . By such movement, the secondary transfer roll 8 comes into contact with the intermediate transfer member 3 only when necessary, and the blade 9 comes into contact with the secondary transfer roll 8. And the mountain scraper 1
As the blade 6 swings with the movement of the blade 9, the toner scraped off from the secondary transfer roll 8 is leveled at the tip of the blade 9 and is deposited flat as shown by reference numeral 12a without forming a mountain. I will do it. In this embodiment, the support plate 21
Swings following the movement of the cam 23, and the support plate 1
9 and 20 are made to move with the support plate 21.
However, the present invention is not limited to this embodiment, and the support plate 21 and the support plates 19 and 20 may be moved by the operation of individual cams or the suction operation of a solenoid or the like. As is apparent from the above description, according to the first aspect of the present invention, the toner deposited in the toner collection container is flattened, so that the toner can be used in a short time. Mountains can be prevented. Therefore, it is possible to solve the problem that the peak of the toner is high and the recording medium is contaminated by wrapping around the blade from both ends of the transfer roll. Further, it is not necessary to newly provide a separate member or a separate driving source in order to flatten the peak of the toner, and there is an effect that the support plate of the blade used conventionally can be simply extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a main part of a cleaning device according to an embodiment of the present invention. FIG. 2 is a plan view of a main part of the cleaning device according to the embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a main configuration of an image forming apparatus including a cleaning device according to an embodiment of the present disclosure. FIG. 4 is a schematic view showing a conventional color electrophotographic transfer device. [Description of Signs] 1 photoconductor drum, 2 developing device, 3 intermediate transfer member, 4 backup roll, 8 secondary transfer roll, 9 blade, 10 toner collection container, 1
2, 12a: toner, 16: pile breaking member, 21:
Support plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/16

Claims (1)

(57) Claims: 1. A latent image carrier on which a toner image corresponding to image information is formed, and an intermediate transfer body on which an unfixed toner image is primarily transferred from the latent image carrier. An image forming apparatus includes: a transfer roll that secondarily transfers an unfixed toner image from the intermediate transfer body to a recording medium; and a backup roll that supports the intermediate transfer body from the back side at a position facing the transfer roll. A blade for separating toner adhered to the transfer roll, a support plate for supporting the blade, and a transfer timing in a direction in which the blade comes into contact with the transfer roll at a transfer timing. And a driving unit that swings the support plate so that the blade moves in a direction away from the transfer roll at a non-transfer timing; In order to receive the toner separated from the copying roll, a toner collection container disposed below the blade and a toner accumulated in the toner collection container can be leveled with the swing of the support plate. A cleaning device for a transfer roll, comprising: a toner strip member extending from the support plate.