JPH056128A - Intermediate transcription body cleaning device for full color image forming device - Google Patents

Abstract

PURPOSE:To prevent generation of toner filming so as to prevent image fog due to toner filming over transfer paper. CONSTITUTION:In an intermediate transcrption body cleaning device of a full color image forming device, with which color images formed in order on a recording medium 7 formed into a belt with color developer such as yellow, magenta, and cyanogenl are transcribed on an intermediate transcrption body 10 and piled so as to form full color images, the circumferential length of the intermediate transcription body 10 is formed over the length of a full sized maximum transcription paper sheet to be used, and a cleaning blade means 30 is detachably provided on the intermediate transcription body 10 between an image transcription position B from the intermediate transcription body 10 to the transfer paper and a toner image transcription position A from the belt-like recording medium 7 to the intermediate transcription body 10. A control means 33 to control contact or separation of the cleaning blade means 30 so as not to generate scratching traces of the blade in the image transcription territory of the intermediate transcription body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade cleaning device for an intermediate transfer member of a full color copying machine.

[0002]

2. Description of the Related Art In a conventional full-color copying machine, yellow, magenta, and cyan toner images formed on a belt-shaped recording medium (hereinafter referred to as a photoconductor) are also belt-shaped at the primary transfer portion. The images were sequentially transferred onto the formed intermediate transfer member to form a full-color image on the intermediate transfer member.

The full-color image formed as described above is transferred to the secondary transfer portion at the same timing at the secondary transfer portion.
It was transferred to the fixing unit after being transferred to the transfer paper that was conveyed to the next transfer unit.

Residual toner on the intermediate transfer member after transfer has been removed by, for example, a cleaning blade. The cleaning blade is configured to come into contact with and separate from the intermediate transfer member by controlling the ON / OFF state of the solenoid.

Specifically, a timing roller provided in the paper transport path portion before the intermediate transfer member activates a timer in synchronization with the timing at which the transfer paper starts to be transported to the secondary transfer portion, and a preset time is set. Turn the solenoid on and off later
I was letting it. Thus, when the cleaning blade is brought into pressure contact with the intermediate transfer member, the scratch mark D of the blade is inevitable.
(Fig. 3) was likely to occur.

[0006]

However, in the conventional intermediate transfer member cleaning device, the contact and separation control of the cleaning blade is performed only for the purpose of removing the residual toner on the intermediate transfer member. No consideration was given to scratch marks. Therefore, when the scratch marks generated on the intermediate transfer member are present at the primary transfer portion,
When the next transfer is performed, the toner is reversely transferred onto the photosensitive member, so-called toner filming occurs, and there is a problem that the image transferred to the transfer paper is fogged.

[0007]

According to a first aspect of the present invention, a color toner image sequentially formed on a belt-shaped recording medium (7) by yellow, magenta, and cyan color developers is used as an intermediate transfer member (10). In an intermediate transfer member cleaning device of a full-color image forming apparatus that forms a full-color image by transferring and superimposing it on top of one another, the circumference of the intermediate transfer member (10) is equal to or larger than the length of the maximum full-size transfer paper used. And an image transfer position (B) from the intermediate transfer body (10) to the transfer paper and a toner image transfer position (A) from the belt-shaped recording medium (7) to the intermediate transfer body (10). Cleaning blade means (3) for removing the residual toner on the intermediate transfer body (10) during
0) is provided in such a manner that it can be brought into contact with and separated from the intermediate transfer member (10), and in the case of full-color copying onto a full-size transfer paper, the intermediate transfer member (7) is transferred from the belt-shaped recording medium (7) during the first copying cycle. 10) The intermediate transfer member (1) after the rear end of the cyan toner image transferred onto the transfer paper has passed through the cleaning blade means (30) and the image has been transferred to a transfer paper.
Before the image leading edge position of 0) reaches the cleaning blade means (30), the cleaning blade means (30) is brought into contact with the surface of the intermediate transfer body (10) and the second copying cycle is performed. Before the leading edge of the yellow toner image transferred from the belt-shaped recording medium (7) onto the intermediate transfer body (10) reaches the cleaning blade means (30), and the intermediate transfer body (10). Before the abutting position of the cleaning blade means (30) reaches the toner image transfer position from the belt-shaped recording medium (7) to the intermediate transfer body (10), the cleaning blade (30) is moved to the intermediate position. Transfer body (1
It is characterized in that a control means (33) for controlling to separate from (0) is provided.

According to a second aspect of the present invention, when the control means performs full color transfer on a half size transfer paper,
The trailing end of the magenta toner image transferred from the belt-shaped recording medium (7) to the intermediate transfer body (10) at the time of the first copying cycle is the cleaning blade means (30).
Before the image front end of the intermediate transfer member (10) after being transferred to the transfer paper at the image transfer position (B} to the transfer paper after passing through the section reaches the cleaning blade means (30). The cleaning blade means (30) is brought into contact with the surface of the intermediate transfer member (10), and the yellow toner image at the time of the second copying cycle is transferred from the belt-shaped recording medium (7). ) After the rear end of the upper position has passed the cleaning blade means (30), the front end of the yellow image of the intermediate transfer body (10) on which the yellow toner image is transferred reaches the cleaning blade means (30). Before, the cleaning blade means (30) is controlled so as to be separated from the intermediate transfer body (10).

[0009]

According to the above-described intermediate transfer member cleaning device, since the cleaning blade does not come to the image area of the intermediate transfer member for transferring the toner image from the belt-shaped recording medium, toner filming occurs. Without it, it is possible to prevent image fogging due to toner filming on the transfer paper.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an intermediate transfer member section according to the present invention. FIG. 2 is a schematic configuration diagram of a full-color copying machine according to the present invention.

As shown in the figure, a transparent original placing table 1 is arranged on the upper surface of the main body of the copying machine. This document table 1
An exposure optical system 2 is provided below the exposure optical system 2. The exposure optical system 2 includes a light source lamp 2a for irradiating the original 13 placed on the original placing table 1 with light and a reflection from the original 13. A plurality of reflecting mirrors 2b for guiding the light onto the photoconductor 7 as shown by a chain line, and an imaging lens 2c arranged on the optical path,
The color separation filter 2d includes color filters of three primary colors of red, green, and blue.

On the optical axis of the exposure optical system 2, there is arranged a belt-shaped photosensitive member 7 made of an organic photosensitive member (OPC) which is irradiated with an optical image subjected to exposure scanning. 7
Paper feed cassettes 8 and 9 containing transfer paper 19 are disposed on the paper input side. The paper feed rollers 23 and 24 are provided on the upper surfaces of the paper feed cassettes 8 and 9, respectively.
Are provided, and these paper feed rollers 23, 24 are provided, and these paper feed rollers 23, 24 eject the transfer paper 19 from the paper feed cassettes 8 and 9 toward the intermediate transfer body 10. It is designed to be sent to. A timing roller 25 is provided on the delivery side of the paper feed rollers 23 and 24 in the direction of the intermediate transfer body 10. The timing roller 25 is rotated in synchronization with the intermediate transfer body 10. It has become.

The intermediate transfer member 10 is formed by heating a binder resin such as a polycarbonate resin to a melting temperature and adding a conductive material such as carbon black in an amount of 1 to several tens% by weight to form a film or tube ( Stretched). The electric resistance value of the intermediate transfer member 10 thus formed is 1 × 10 ⁷ to 1 ×.
It is stored in the mouth at 10 ⁹ Ω. Further, the circumference of the intermediate transfer member is set to be longer than the maximum length of a full-size transfer sheet.

The light for each color component transmitted through each color filter of the color separation filter 2d in the above exposure scanning is applied to the photoconductor 7 that is uniformly charged by the charging charger 16, and the photoconductor 7 is at the portion A. Exposed. As a result, the photoconductor 7
A yellow electrostatic latent image corresponding to the image of the original 13 is formed. After that, each of the electrostatic latent images is separated by the color separation filter 2d.
In the opposing portion of the developing tank 4 having the yellow developer which is the complementary color of the above, it is developed with the developer supplied from the developing magnet roller and is visualized to form a toner image. And
This toner image is transferred by the primary transfer device 21 to the intermediate transfer member 10.
Will be transferred to.

When the yellow copying cycle is completed, the photoconductor 7 is cleaned by the cleaning device 17 and is discharged by the discharge lamp 26. And
The magenta and cyan toner images are transferred to the intermediate transfer body 10 in the same copy cycle as described above.

When each of the above copy cycles is executed,
The toner image for each color component is transferred to the same position of the intermediate transfer body 10 by the primary transfer device 21, and the toner for each color component is overlaid to form one completed toner image. Become.

The intermediate transfer member 10 is rotatably driven by the first to third rollers 18a, 18b and 18c, and is in pressure contact with the driving roller 15 which rotatably drives the photosensitive member 7. A primary transfer device 21 is arranged on the back surface side of the intermediate transfer member 10 in a portion where the drive roller 15 is pressed.

A secondary transfer roller 22 is provided on the surface side of the intermediate transfer member 10 in the area where the third roller 18c is provided. The peeling plate 20, the conveyor belt 11, and the fixing device 12 are arranged in this order on the delivery side of the secondary transfer roller 22.

The photosensitive member 7 irradiated with the irradiation light from the exposure optical system 2 is rotated and driven by the driven roller 14 and the driving roller 15.

A charger 16 for charging the photoconductor 7 and a destaticizing lamp 26 for destaticizing the photoconductor 7 are provided on the outer periphery of the photoconductor 7 on the side of the driven roller 14.
Below the photoconductor 7 in the vicinity of the charging charger 16, a cleaning device 17, which is a cleaning unit that removes the toner remaining on the photoconductor 7, is provided.
The cleaning device 17 is provided with cleaning blades 17a, 17a made of urethane or the like, for example.
Numeral 17a is pressed against the photoconductor 7 so as to scrape off, for example, toner remaining on the photoconductor 7.

In the vicinity of the central portion above the photoconductor 7, a black and white developing tank 3 in a non-contact state with the photoconductor 7,
Color developing tanks 4 to 6 are provided, and yellow, magenta, and cyan color developers are individually stored in the color developing tanks 4 to 6.

Next, the operation of the color copying machine having the above construction will be described below. First, the copy mode is executed by pressing a copy start switch (not shown). This copy mode has a copy cycle in which yellow, magenta, and cyan are developed and transferred to the intermediate transfer body 10. When the copy mode is executed, first, the yellow copy cycle is executed. become.

That is, the original document 1 placed on the original document table 1
3 is irradiated with light from the light source lamp 2a, and exposure scanning is performed. The reflected light from the original 13 is incident on the color separation filter 2d through the reflecting mirrors 2b ... And the imaging lens 2c, and is separated into color components by the color separation filter 2d.

On the other hand, the transfer papers 19 accommodated in the paper feed cassettes 8 and 9 are fed one by one to the timing roller 25 by the paper feed rollers 23 and 24, respectively.
Conveys the transfer paper 19 between the intermediate transfer body 10 and the transfer roller 22 in synchronization with the intermediate transfer body 10. The transferred transfer paper 19 is separated from the intermediate transfer body 10 by the peeling plate 20 after the toner image on the intermediate transfer body 10 is transferred by the transfer roller 22, and is introduced into the fixing device 12 by the transfer belt 11. Then, after the color toner image is fixed on the transfer paper 23 and then discharged to the outside, the one-time copy mode ends.

Next, with reference to FIGS. 1, 4 and 5, the construction of the cleaning device for the intermediate transfer member 10 and the cleaning control will be described.

The cleaning blade 30 includes an image transfer position (B) from the intermediate transfer member 10 to a transfer sheet and a photosensitive member (7).
The toner image transfer position (A) from the intermediate transfer body 10 to the intermediate transfer body (10) is provided so as to be capable of contacting and separating from the intermediate transfer body 10. Specifically, the cleaning blade 30 has a solenoid 31.
Is held so as to be rotatable (arrow in the figure) about the shaft 32 by turning on and off. The cleaning blade 30 comes into contact with and separates from the intermediate transfer member 10 in accordance with the above rotation. That is, when the solenoid 31 is OFF, the cleaning blade 30 and the intermediate transfer body 10 are in contact with each other, and when the solenoid is turned ON, the cleaning blade 30 rotates about the shaft 32 to perform the intermediate transfer. Separated from body 10. ON of solenoid 30-
The OFF control is performed by the control circuit 33.

Next, the cleaning control when copying a full size image (here, A3 size) will be described with reference to the time chart of FIG.

The full size original document placed on the original document table 1 is exposed and scanned three times. First, the electrostatic latent image formed on the photoconductor 7 in the first exposure scan is visualized by the yellow developer and transferred onto the intermediate transfer body 10 at the primary transfer position A. Specifically, the transfer rollers 21a, 2
1b DC high voltage (500-1000V)
Is applied to transfer the image.

The transfer of the yellow toner image is performed during the first rotation of the intermediate transfer member 10. At this time, the cleaning blade 30 is held at a position away from the intermediate transfer member 10 by the solenoid 31. Transfer is not performed during the subsequent second rotation of the intermediate transfer member 10, and is formed on the photosensitive member 7 by the second exposure scanning when the image front end of the yellow toner image reaches the primary transfer position on the third rotation. A magenta toner image obtained by visualizing the formed latent image with a magenta developer is transferred in an aligned manner. In the fourth round of the intermediate transfer member 10, the transfer is not performed as in the second round, and the subsequent 5th round is performed.
When the leading edge of the magenta toner image reaches the primary transfer position A on the circumference, the cyan toner image obtained by visualizing the latent image formed on the photoconductor 7 by the third exposure scan with the cyan developer is positioned. They are also overlaid and transferred.

Then, the rear end of the cyan toner image transferred from the photoconductor 7 onto the intermediate transfer member 10 has passed through the cleaning blade 30 and a full color image in which three colors of yellow, magenta and cyan are superposed. However, the position of the leading edge of the image on the intermediate transfer body 10 after being transferred to the transfer sheet conveyed to the secondary transfer section B by the timing roller 25 in synchronization with the intermediate transfer body 10 is set to the cleaning blade 30 section. Before reaching, the solenoid 31 is turned off to bring the cleaning blade 30 into contact with the intermediate transfer member 10 to start cleaning.

In the copy cycle of the second sheet, before the leading edge of the yellow toner image transferred from the photoconductor 7 onto the intermediate transfer body 10 reaches the cleaning blade 30, the intermediate transfer body 10 is not yet reached. Before the contact position of the cleaning blade 30 reaches the primary transfer position A where the toner image is transferred from the photoconductor 7 to the intermediate transfer member 10, the solenoid is turned on.
The cleaning blade 30 is controlled to be N and separated from the intermediate transfer member 10.

The above conditions will be described more concretely.
The peripheral length of the intermediate transfer body is 1, the length of the long side of the A3 size transfer paper is a3, the peripheral speed of the intermediate transfer body is v, and the distance from the contact portion between the cleaning blade and the intermediate transfer body to the primary transfer position is d, the time from the start of conveyance of the sixth transfer intermediate transfer member of the first copy to the cleaning blade ON is T1, the time the cleaning blade is ON is T2, and the intermediate transfer member of the second copy is 1 Assuming that the time from the start of conveyance on the circumference to the cleaning blade OFF is T3, and the time from the cleaning blade OFF to the transfer end of the yellow toner image on the intermediate transfer member is T4, the ON / OFF timing of the cleaning blade is as follows. Need to meet.

That is, T1 <(ld) ÷ v, T2 ≧ a3
By performing the ON-OFF control of the cleaning blade so that the conditions of ÷ v, T3 <(ld) / v, T4 <d ÷ v are satisfied, the image transfer area on the intermediate transfer body is set at the time of primary transfer. Since the scratches of the blade do not come, it is possible to prevent the occurrence of toner filming and the occurrence of fog in the final image on the transfer paper.

Next, the cleaning control when copying a half size image (A4 size in this case) will be described with reference to the time chart of FIG.

In the first copy cycle, the intermediate transfer member 10 first starts to rotate and the yellow toner image is transferred from the photosensitive member 7 to the intermediate transfer member 10 in the first half of the first rotation (position A). When the image on which the yellow toner image has been transferred reaches the primary transfer position during the subsequent second rotation of the intermediate transfer member 10, the magenta toner image is transferred in an overlapping manner with its position aligned. When the magenta toner image on the intermediate transfer body reaches the primary transfer position on the subsequent third round, the cyan toner image is transferred in the same position.

Then, after the rear end of the magenta toner image transferred from the photosensitive member 7 onto the intermediate transfer member 10 passes through the contact portion of the cleaning blade 30, the superimposed color image is transferred from the intermediate transfer member 10 to the transfer paper. Image transfer position,
That is, the solenoid 31 is turned off before the image leading edge position of the intermediate transfer body 10 after the transfer to the transfer paper at the secondary transfer position reaches the contact portion of the cleaning blade 30.
Then, the cleaning blade 30 is brought into contact with the intermediate transfer member 10 to start cleaning.

In the second copy cycle, the yellow toner image is transferred after the trailing end of the position on the intermediate transfer body 10 where the yellow toner image is transferred from the photoconductor 7 passes through the cleaning blade 30. Before the leading edge of the yellow toner image on the intermediate transfer body 10 reaches the cleaning blade 30, the solenoid 31 is turned on to separate the cleaning blade 30 from the intermediate transfer body 10.

The above conditions will be described more concretely.
From the photoconductor 7 to the intermediate transfer body 1 in the first copy cycle
From the start of the transfer of the cyan toner image to 0, the intermediate transfer member 1
The time taken for the trailing edge of the magenta toner image transferred on the image 0 to pass through the contact portion of the cleaning blade 30 is T
5, in the same copy cycle of the first sheet, the leading edge of the cyan toner image transferred onto the intermediate transfer member 10 from the start of the transfer of the cyan toner image from the photosensitive member 7 to the intermediate transfer member 10 becomes the contact portion of the cleaning blade 30. The time until reaching T6 is T6, and the intermediate transfer member 10 on which the yellow toner image should be transferred from the photosensitive member 7 from the start of transfer of the yellow toner image from the photosensitive member 7 to the intermediate transfer member 10 in the second copy cycle.
The time until the rear end of the upper position reaches the contact portion of the cleaning blade 30 is T7, and from the start of transfer of the yellow toner image from the photoconductor 7 to the intermediate transfer member 10 to the intermediate transfer member in the second copy cycle. Letting T8 be the time until the tip of the yellow toner image transferred to 10 reaches the contact portion of the cleaning blade 30 and a4 is the length of the long side of the A4 size transfer paper, the cleaning blade is turned on and off.
Must meet the following conditions.

That is, T5> (a4-d) ÷ v, T6 <
(L-d) / v, T7> (a4-d) / v, T8 <(l
By controlling the cleaning blade ON / OFF so that the condition of −d) ÷ v is satisfied, there is no scratch of the blade on the image transfer area on the intermediate transfer member during the primary transfer. Can be prevented, and fogging can be prevented from occurring in the final image on the transfer paper.

The transfer sheets of A3 size and A4 size have been described above, but the same applies to other sizes, and the description thereof will be omitted.

[0041]

According to the intermediate transfer member cleaning device of the present invention, it is possible to prevent the occurrence of toner filming and prevent image fog on the transfer sheet due to toner filming.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an intermediate transfer member according to the present invention.

FIG. 2 is a schematic configuration diagram of a full-color copying machine according to the present invention.

FIG. 3 is a schematic diagram showing blade scratch marks of a conventional intermediate transfer member.

FIG. 4 is a time chart of cleaning control when copying a full size image according to the present invention.

FIG. 5 is a time chart of cleaning control when copying a half-size image of the present invention.

[Explanation of symbols]

7 Belt-shaped recording medium 10 Intermediate transfer body 30 cleaning blade means 33 Control means

Claims (2)

[Claims] 1. A full-color image forming apparatus for forming a full-color image by transferring color toner images sequentially formed on a belt-shaped recording medium with yellow, magenta, and cyan color developers onto an intermediate transfer member and superposing them. In the intermediate transfer member cleaning device, the peripheral length of the intermediate transfer member is formed to be equal to or greater than the length of the maximum full-size transfer paper used, and the image transfer position from the intermediate transfer member to the transfer paper and the belt shape are A cleaning blade means for removing the residual toner on the intermediate transfer member is provided between the recording medium and the toner image transfer position on the intermediate transfer member so as to be able to come into contact with and separate from the intermediate transfer member. Toner image transferred from the belt-shaped recording medium onto the intermediate transfer member at the time of the first copy cycle in the case of full-color copying to After the trailing edge has passed through the cleaning blade means part, and before the image leading edge position of the intermediate transfer body after transferring the image to the transfer paper reaches the cleaning blade means part, the cleaning blade means is Before the front end of the yellow toner image transferred from the belt-shaped recording medium onto the intermediate transfer member during the second copying cycle is brought into contact with the surface of the intermediate transfer member and before reaching the cleaning blade means. Before the cleaning blade means contact position on the intermediate transfer body reaches the toner image transfer position from the belt-shaped recording medium to the intermediate transfer body, the cleaning blade means is separated from the intermediate transfer body. An intermediate transfer member cleaning device for a full-color image forming apparatus, which is provided with control means for controlling. 2. When the control means performs full-color copying on a half-size transfer paper, the magenta toner image transferred from the belt-shaped recording medium onto the intermediate transfer body during the copying cycle of the first sheet is recorded. Before the image front end of the intermediate transfer member after the rear end has passed through the cleaning blade means part and after being transferred to the transfer paper at the image transfer position onto the transfer paper, reaches the cleaning blade means part. The means is brought into contact with the surface of the intermediate transfer body, and the rear end of the position on the intermediate transfer body where the yellow toner image in the second copying cycle is transferred from the belt-shaped recording medium is the cleaning blade means part. Before the tip of the yellow toner image on the intermediate transfer body after the yellow toner image is transferred after passing the cleaning blade means The intermediate transfer member cleaning device for a full-color image forming apparatus according to claim 1, wherein the cleaning blade means is controlled so as to be separated from the intermediate transfer member.