JPH0358072A - Cleaner for image forming device - Google Patents

Abstract

PURPOSE:To accurately detect an amount of residual toner and to apply a suitable bias voltage by detecting the potential of a photosensitive drum on which an electrostatic latent image is formed, and calculating a bias value from the potential data. CONSTITUTION:A potential sensor Sv detects the potential of the photosensitive drum 8, on which a latent image is formed. A CPU detects a bias value, which is required for cleaning, in relation to the detected potential. The bias voltage is applied to the photosensitive drum via a bias control circuit. The electrostatic force of the photosensitive drum 8 for residual toner is weakened by the bias voltage, and the residual toner T is removed by a cleaning blade 141 and a fur brush. The toner is discharged to a toner recovering box by a spiral 148.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for removing residual toner after image transfer of an image forming apparatus such as a copying machine.

[Conventional technology]

Conventionally, in a cleaning device for an image forming apparatus using a cleaning member such as a magnetic brush or a fur brush, deterioration of the photosensitive characteristics of the photosensitive drum due to applying a bias voltage higher than necessary to the magnetic brush or fur brush has been prevented. The amount of toner remaining on the surface of the photoreceptor drum after transfer is detected by a photoelectric conversion element, and the minimum bias voltage capable of cleaning is applied to the magnetic brush or fur brush according to the detection output. A cleaning device has been proposed (Japanese Unexamined Patent Publication No. 176085/1985).

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional technology, a photoelectric conversion element is provided between the transfer section and the cleaning section to directly detect the amount of residual toner on the photoreceptor drum. There is a problem in that toner and paper dust scatter and adhere to the light receiving portion of the photoelectric conversion element, making it impossible to accurately detect the amount of remaining toner.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a cleaning device for an image forming device that accurately detects the amount of residual toner and applies a suitable bias voltage. .

[Means to solve the problem]

In order to solve the above problems, the present invention provides a cleaning device for an image forming apparatus that applies a bias voltage to a cleaning member to remove residual toner from a photoreceptor drum.
The apparatus includes a potential detection means for detecting the potential of the photosensitive drum on which an electrostatic latent image is formed by exposure, and a bias setting means for setting the bias voltage according to the detection signal.

[Effect]

According to the cleaning device for an image forming apparatus configured as described above, the potential of the photoreceptor drum on which an electrostatic latent image is formed by exposure is detected between the exposure section and the development section, and the potential of the photoreceptor drum is detected between the exposure section and the development section. When the electrolatent image section rotates to the cleaning section, a suitable bias voltage according to the detection signal is applied to the cleaning member, and the toner remaining on the photoreceptor drum is removed.

〔Example〕

The overall configuration of a copying machine using a cleaning device according to the present invention will be explained with reference to FIG.

In the figure, a contact glass 2 on which a document is placed is provided at the top of a copying machine main body 1, and a document presser 3 is provided above the contact glass 2. Further, an optical system consisting of an original irradiation lamp 4, a retraction plate 5, mirrors 61, 62, 63, 64, and a lens assembly 7 is constructed below the contact glass 2 in the copying machine main body 1. Light passing through the optical system is guided to an exposure area A of a rotatable photosensitive drum 8. Around the photoreceptor drum 8, in the order of rotational direction, there is a main charging body 9 including a corona discharger, a blank lamp 10, a developing section 1, a transfer charging section 12, a separation charging section 13, a cleaning section 14, and a static eliminating section. A lamp 15 and the like are provided.

Here, the blank lamp 10 erases unnecessary charges from the photosensitive drum 8 charged by the main charging section 9, that is, charges other than the area where the electrostatic latent image is formed (hereinafter referred to as the image forming area). It is something. Further, the developing section 11 has a developing roller 111, which supplies toner T onto the photoreceptor drum 8 and develops the electrostatic latent image formed by the exposure into a toner image. be. Further, the transfer charging section 12 electrostatically transfers the toner image formed on the photoreceptor drum 8 onto the conveyed transfer paper, and the separation charging section 13 consists of a corona discharger or the like.
This is for electrostatically separating the transfer paper from the photoreceptor drum 8 after transfer. Further, the cleaning section 14 removes residual toner, paper powder, etc. on the surface of the photosensitive drum 8 after the transfer paper is separated from the photosensitive drum 8.

As shown in FIG. 1, the cleaning section 14 includes a cleaning blade 141 and a fur brush FB for removing toner T remaining on the photoreceptor drum 8, and a spiral 148 for discharging the removed toner T. ing. The cleaning blade 141 is made of a flexible flat plate made of rubber, sponge, etc., and is attached to the node mounting plate 143. Further, the blade 1 node attachment plate 143 has a weight 145 at one end, and is attached to the other end of a blade support member 144 rotatably attached to a shaft 146 by a blade 1 node attachment pin 142.

With this configuration, the blade support member 144 is attached to the weight 1.
45 rotates in the opposite direction around the sleeve 146,
The rotational force brings the tip of the cleaning blade 141 into pressure contact with the photoreceptor drum 8 at a predetermined pressure. Then, as the photosensitive drum 8 rotates clockwise, the toner T remaining on the surface of the photosensitive drum 8 is scraped off and removed by the cleaning blade 141. Further, below the cleaning blade 141, as shown in FIG. 2, a suitable number of fur brushes FB consisting of fur brushes ps1, FB2 to FBn are arranged in parallel to the rotation axis of the photoreceptor drum 8. The tip of the brush is arranged so as to rub the surface of the photoreceptor drum 8.

As shown in FIG. )), and a predetermined bias voltage is applied from the bias control 32 as described later. This bias voltage weakens the electrostatic attraction force of the photoreceptor drum 8 to the residual toner T, and the residual toner T is easily swept and removed from the surface of the photoreceptor drum 8 by the fur brush FB. Note that the toner T adhering to the fur brush FB is scraped off by the scraper 147. Then, the cleaning blade 141
The residual toner T removed by the fur brush FB is discharged by the spiral 148 to a toner collection box (not shown).

Returning to FIG. 3, an exposure area A from the optical system is provided on the photosensitive drum 8 between the main charging section and the blank lamp 10, and further between the exposure area A and the developing section 11. A potential sensor Sv is provided to detect the potential of the photosensitive drum 8 on which an electrostatic latent image is formed by exposure. The potential sensor SV is connected to the fur brush FB1F as shown in FIG.
Multiple potential sensors SVI corresponding to B2 to FBn
, SV2 to SVn, and are disposed facing the photoreceptor drum 8 and parallel to the rotation axis of the photoreceptor drum 8.

That is, a divided area D obtained by dividing the circumferential surface of the photoreceptor drum 8
1, and the potentials of D2 to Dn are respectively detected. Further, a conveying roller 1 is provided at the bottom of the developing section 11.
A paper feeding and transporting mechanism 20 consisting of 7 pairs, a plurality of guide plates 16, 18, and a plurality of 19 pairs of carry-in rollers is disposed. It is fed to the body drum 8 side. A conveyance belt assembly 23 , a fixing section 24 , a delivery roller 25 , and a tray 26 are provided on the downstream side of the separation charging section 13 in the transfer paper conveyance direction, and transfer the transfer paper transferred by the transfer charging section 12 to the fixing section 24 . After being conveyed and fixed by a heat roller 241 and a pressure roller 242 in the fixing section 24, the toner is discharged to a receiving tray 26 through a discharge port 25.

Next, the operation of the cleaning device according to the present invention will be explained using FIG. 2. As mentioned in 1 above, the potential sensor SV is composed of n sensors SVI, Sv2 to SVn, and each potential sensor SV1, SV2 to SV
n is an area D1 obtained by dividing the photoreceptor drum 8 into n, respectively;
The potentials of D2 to Dn are detected. The detection signals from the potential sensors SV1, SV2 to SVn are input to the A/D converter 27 as parallel signals. The control circuit 28 consisting of a microcomputer is
When the copy start signal from the two switches is detected, A
output a predetermined sampling pulse to the /D converter 27,
Each potential signal detected by the potential sensors SvISv2 to Svn is converted into digital data E1, E2 to En, and the remaining toner T in each divided area DI, D2 to Dn is calculated from the potential data E1, E2 to En. The minimum bias values B1, 82 to Bn necessary for removal are calculated. Further, the control circuit 28 receives a drive pulse from the motor 30 for driving the photoreceptor drum 8, and from the drive pulse, the position at which the electric potential sensor SV starts detecting electric shock is rotated to a position where it contacts the fur brush FB. Measure the timing of rotational movement. Then, when the potential detection start position rotates to a position where it comes into contact with the fur brush FB, the control circuit 28 adjusts the bias value Bl,
B2 to Bn are output to the bias control circuit 32 via the D/A converter 31. The bias control circuit 32 applies bias voltages of the bias values BIB2 to Bn to the fur brushes FBIB2 to FBn, respectively, based on the analog signal D/A converted by the D/A converter 31 to the photosensitive drum 8.
The voltage is applied so that the polarity is opposite to that of the voltage. As a result, the potential of each divided area of the photoreceptor drum 8 is suitably neutralized, the electrostatic adsorption force of each divided area to the residual toner T is weakened, and the residual toner T is transferred to the far plan FBI, FB2 to FBn.
It is easily removed from the surface of the photoreceptor drum 8.

Note that the potential sensor SVI. Taking in the detection signal by Sv2 to SVn and the above bias value Bl, 82 to
Although the output of Bn is performed individually, the output of the detection signal and bias data may be performed serially.

〔Effect of the invention〕

As explained above, according to the present invention, static electricity/
8 The potential of the photoreceptor drum on which the image has been formed is detected and the bias value is calculated from the potential data, so residual toner does not scatter and adhere to the sensor, and information regarding the amount of residual toner is accurate. It also allows stable detection and accurate bias value setting. This provides stable cleaning performance.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of a cleaning device for an image forming apparatus according to the present invention, and FIG. FIG. 3 is a diagram showing the overall configuration of an image forming apparatus equipped with a cleaning device according to the present invention.

Claims (1)

[Claims] 1. In a cleaning device for an image forming apparatus that applies a bias voltage to a cleaning member to remove residual toner from a photoreceptor drum, a potential detection means detects the potential of the photoreceptor drum on which an electrostatic latent image is formed by exposure. and bias setting means for setting the bias voltage according to the detection signal.