JPS6333158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor cleaning device that uses a brush roll made of insulating fibers to remove toner remaining on the surface of the photoreceptor.

Conventionally, as shown in FIG. 1, a conventional cleaning device of this type has a brush roll b made of insulating fibers in sliding contact with the surface a' of a photoreceptor a, and the brush roll b made of insulating fibers (polyacetal). A first sliding member (Flicker) c and a second sliding member (Flicker) d made of insulating resin (Teflon) are brought into sliding contact, and the brush roll b is charged (-) by the first sliding member c. , one in which the brush roll b is charged to (+) by the second rubbing member d is known. e is a pre-cleaned corotron.

With this structure, the first rubbing member c charges the brush roll b to (-) to help remove the residual toner on the photoreceptor surface a', and the second rubbing member d charges the brush roll b to a negative charge. The photoreceptor surface is charged to (+) to help remove toner adhering to the brush roll.
Clean to remove residual toner from a′.

However, with this structure, the brush roll b is charged to different polarities by the first and second rubbing members c and d and the photoreceptor a, so the charging balance of the three members is disrupted and the brush roll b is charged to one of the polarities. Charge build-up is likely to occur, and the brush roll b cannot be properly set and charged to a predetermined polarity, making it impossible to obtain good cleaning performance.

In addition, with only one brush roll, good cleaning performance cannot be obtained unless the roll is rotated at a circumferential speed of 5 m/sec or more and the roll bites into the photoreceptor t is 2.5 mm or more.

As a result, photoreceptor wear, toner filming, etc. occur, making it difficult to maintain image quality over a long period of time.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cleaning device for an electrophotographic photoreceptor that causes minimal impact on the photoreceptor and has good cleaning performance for a long period of time.

An embodiment of the present invention will be described below with reference to FIG.

Photoreceptor (photoreceptor made of selenium-based P-type semiconductor)
1 is rotated in the direction of arrow A, and the toner image formed on the photoreceptor is transferred to the paper in the transfer process. However, since residual toner adheres to the photoreceptor surface 1a after transfer, the residual toner is removed by a cleaning device 2 in a cleaning process.

The details of the cleaning device will be explained below.

Reference numeral 3 denotes a pre-cleaning corotron arranged opposite to the photoreceptor surface 1a, to which a negative biased high voltage AC (AC6KV, -DC2KV) is applied.

4 is a case, which includes a box-like main body 5 and an upper cover 6.
and a lower cover 7, and has an opening 8 opening to the photoreceptor 1.

Inside the opening 8 are first and second brush rolls 9 and 10 made of insulating fiber (for example, Dynel).
(both have an outer diameter of 50φmm) are spaced apart in the circumferential direction of the photoreceptor and are provided so as to nip and slide into contact with the photoreceptor surface 1a to a depth of approximately 1.5 mm. The second brush roll 10 rotates at about 1200 rpm in the opposite direction to the photoreceptor 1 and moves in the same direction at the contact portion B, while the second brush roll 10 rotates at about 1200 rpm in the same direction as the photoreceptor 1 and moves in the opposite direction at the contact portion C. In addition, the first and second brush rolls 9, 10
is rotated at a circumferential speed that is approximately 10 times faster than the circumferential speed of the photoreceptor 1.

Reference numeral 11 designates a first conductive member that comes into sliding contact with the first brush roll 9, and is provided on an insulating block 12 fixed to the lower cover 7, and is connected to a DC power source 13 to supply (+) DC voltage (+5KV/DC). ) is applied, so the first brush roll 9 is always frictionally charged (+).

A second conductive member 14 is in sliding contact with the second brush roll 10, and is fixed to the upper cover 6 and is connected to a DC power supply 15 to which a (-) DC voltage (-5KV/DC) is applied. Therefore, the second brush roll 10 is always frictionally charged (-).

Therefore, the residual toner after transfer is on the photoreceptor surface 1.
It reaches the pre-cleaning corotron 3 in a state where it is strongly electrostatically attached to a.

Then, the photoconductor surface 1a and the residual toner are neutralized by the AC corona discharge of the pre-cleaning corotron 3, and the photoconductor surface 1a and the residual toner are charged (-) by the -DC corona discharge.
The residual toner remains on the photoreceptor surface 1 in an extremely unstable state.
a, enters the cleaning device, and comes into sliding contact with the first brush roll 9.

Since the first brush roll 9 is charged (+), when it comes into contact with residual toner that is unstablely attached to the surface of the photoconductor, about half of the residual toner is removed from the surface of the photoconductor by electrostatic adsorption and mechanical wiping action. It is separated and removed from 1a.

Then, the remaining half of the residual toner becomes even more unstable in its adhesion to the photoreceptor, and the second brush roll 10
Enter and make sliding contact.

Since the second brush roll 10 is (-) charged, the (+)-charged residual toner is electrostatically repelled, and the residual toner is completely removed from the photoreceptor surface 1a with the help of mechanical wiping action. Cleaned.

The toner separated from the surface of the photoconductor by the first and second brush rolls 9 and 10 is swept away by the air flow by the brushing action of the first and second conductive members 11 and 14, and is transferred to the upper cover 6 and the scavenge roll 16. The air is transported to an air flow path 17 formed by The scavenge roll 16 is supplied with (+) DC voltage (+5~
6 KVDC) is applied, and the floating toner is adsorbed and collected on the surface of the scavenge roll, scraped off from the surface of the scavenge roll by the blade 18, and carried out of the case 4 by the transport auger 19. Furthermore, several percent of floating toner that is not collected by the scavenge roll 16 is collected by the filter 20, and only clean air is exhausted to the outside of the case 4.

As described above, the cleaning device shown in the embodiment utilizes the blowing action of the brush rolls 9 and 10 without requiring an external air suction source such as a blower, and the first and second conductive members 11 and 14 are connected to the brushes described above. It functions not only to control the charge of the rolls 9 and 10 and to remove the charges, but also to bring out the blowing effect.

It goes without saying that the cleaning device of the present invention can also be used in a brush cleaning device having an external air suction source.

Furthermore, in the above embodiments, a selenium-based semiconductor is used as the photoreceptor, but when using a photoreceptor made of an N-type semiconductor such as ZnO or CdS, the pre-cleaning corotron 3 is operated at a positive biased AC high voltage. The first conductive member 11 may be connected to a (-) DC voltage, and the second conductive member 14 may be connected to a (+) DC voltage.

That is, it is sufficient to apply a voltage of opposite polarity to the charge of the residual toner to the first conductive member 11, and apply a voltage of the same polarity to the second conductive member 14, respectively.

The present invention is as described above, and the first brush roll 9
is charged with a polarity opposite to that of the residual toner due to friction with the first conductive member 11, so that the residual toner on the surface of the photoconductor is electrostatically attracted and mechanically wiped off by sliding contact with the first brush roll 9. About half of the remaining toner is removed by the action, and the remaining residual toner rubs against the second conductive member 14 and comes into sliding contact with the second brush roll 14, which is charged to the same polarity as the residual toner, resulting in electrostatic repulsion and electrostatic repulsion. Completely removed by mechanical wiping action.

Therefore, the cleaning device has good cleaning performance.

In addition, good cleaning performance can be maintained over a long period of time with minimal impact on the photoreceptor.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, and FIG. 2 is a cross-sectional explanatory diagram of an embodiment of the present invention. 1 is a photoreceptor, 3 is a pre-cleaning corotron, 9 is a first brush roll, 10 is a second brush roll, 11 is a first conductive member, and 14 is a second conductive member.

Claims (1)

[Claims] 1. First and second brush rolls 9 and 10 made of insulating fibers and arranged in parallel in the rotational direction so as to rotate in sliding contact with the photoconductor surface 1a and remove toner remaining on the surface 1a; Brush roll 9, 10
The first and second conductive members 1 are rubbed against each other.
1 and 14, the first conductive member 11 is applied with a voltage of opposite polarity to the charge of the residual toner, and the second conductive member 14 is applied with a voltage of the same polarity as the charge of the residual toner. A cleaning device for an electrophotographic photoreceptor, characterized in that a voltage is applied thereto.