JPS6350712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device for an electrophotographic copying machine, and more particularly to an eraser housed in a device that magnetically prevents the intrusion of magnetic powder in a cloud-like magnetic powder atmosphere. The present invention relates to a cleaning device for an electrophotographic copying machine that uses a lamp.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning auxiliary device that can provide excellent cleaning effects in an electrophotographic copying machine that uses a cleaning device that also serves as a developer.

In a two-cycle/one-copy electrophotographic copying machine that uses a developing and cleaning device, a magnetic roll for developing and cleaning is used in combination with a conductive fur brush. In order to further improve the removal efficiency, an erase lamp is used to erase the residual electrostatic charge image on the sensitive material. The present invention aims to enhance the cleaning effect by always sufficiently erasing the residual electrostatic charge image using the erase lamp.

As shown in FIG. 1, the cleaning device according to the present invention includes a conductive fur brush that rubs and rotates on a photoconductor to which an alternating current voltage is applied, a magnetic roll assembly 10a, and a magnetic roll assembly 10a.
A lamp 6 is built in between 10b and a slit-shaped opening 1 is formed.
A protector magnet 5 is provided with the magnet 1 facing the photoreceptor 1 side.

The present invention will be specifically described below with reference to the drawings. In FIG. 1, during the first rotation (first stroke) of the photoreceptor drum, the fur brush 2 is spaced approximately 2 mm from the surface of the photoreceptor 1 by a retracting mechanism (not shown), and the electrostatic latent image formed by charging and exposure. is developed by the ears of magnetic toner 8 formed on the non-magnetic sleeve 10b which rotates around the outer periphery of the magnetic roll 10a at a speed of about 200 rpm, and the toner image on the photoreceptor 1 is transferred to paper in a transfer process (not shown). The first step is completed.

During the second rotation (second stroke) of the photoreceptor drum, there is approximately 20 to 40% of the untransferred residual toner image on the photoreceptor drum 1, and this is developed/cleaned without being charged or exposed for preliminary cleaning. Enter the unit. At this time, the fur brush 2 has an interference area with the photosensitive drum 1 having a width of about 15 mm, and is rotating at about 200 rpm in the direction shown in the drawing. Further, a frit cover bar 3 made of non-magnetic metal (SUS303) to which a voltage of 500 VAC (50 Hz) is applied from a power source 4 is in contact with the fur brush 2 (mixed current is about 70 μA for a brush length of 300 mm). Therefore, the residual electrostatic latent image and residual toner on the photoreceptor drum 1 in contact with the fur brush 2 are affected by the unequal alternating electric field emitted from the tip of the fur brush, and the residual electrostatic latent image and residual toner are erased. As the charge is lost, it is subjected to electrostatic scattering action and mechanical wiping action by the fur brush, and a part of it forms a cloud and is directly collected on the sleeve 10b by the magnetic attraction force of the magnetic roll 10a, and the rest is transferred to the photoreceptor 1. It is evenly distributed and adhered to the top.
When the photoreceptor passes through the rubbing portion of the fur brush 2, a uniform and innumerable fine linear electrostatic charge image is formed on the surface of the photoreceptor due to the action of the alternating electric field applied by the fur brush. This image has a width of 0.05mm and a length of 0.5~ when the fur brush applied voltage is AC and the frequency is 50Hz.
It is about 2 mm, and positive charge images and negative charge images are formed at approximately the same number. Photoreceptor 1
Immediately after passing through the fur brush 2, it is irradiated by the erase lamp 6. If the photoreceptor uses a P-type semiconductor, the positive charge image can be erased, but the negative charge image cannot be erased (in the case of the N-type, the bias (becomes negative). So fur brush 2
By applying a DC bias of +250V in addition to an AC voltage of 500V, it is possible to align all the minute linear electrostatic charge images to positive values. Therefore, the electrostatic charge image is completely erased by light irradiation from the erase lamp 6, and the magnetic toner that is unstablely attached to the photoreceptor is the magnetic toner formed by the main magnetic pole _N1 of the magnetic roll. completely cleaned by the ears.

The erase lamp 6 is covered by a protector magnet 5 having a shape shown in FIG. 2 and having a slit-shaped opening facing the photoreceptor. Further, the two magnets 5 are arranged so that the magnetic poles of the same polarity face each other as shown in FIG. 3, and a repulsive magnetic field is formed in the opening, so that the magnetic powder is prevented from entering.

Contamination of the lamp can be further reduced by shearing the lamp with a transparent plate as shown at 12 in FIG. 1, if necessary.

Therefore, even though the erase lamp 6 is used in an atmosphere where magnetic toner forms a cloud, no magnetic toner adheres to the erase lamp 6, and the amount of light irradiated with it is sufficient to erase the residual electrostatic charge image on the sensitive material. can be sufficiently maintained.

With the above configuration, cleaning can be performed with a combination of magnetic toner resistance of 10 ¹⁵ Ωcm and sensitive material resistance of 10 ¹⁶ Ωcm.

In the above explanation, we have described the case of 2 cycles (development cycle + cleaning cycle)/1 copy, but 1 cycle (development and cleaning is 1 cycle)
The apparatus of the present invention can also be placed at appropriate locations around the photosensitive material even in the case of copying (performed during a cycle) or in the case of copying without synchronizing the photosensitive material with the original.

For example, the following fur brushes are suitable for use in the cleaning device of the present invention: Material: Carbon-containing nylon fiber (e.g. "Beltron" manufactured by Kanebo Co., Ltd.); Electrical resistance 10 ⁵ to 10 ⁶ Ω
cm.

Fiber diameter: 6-15 denier (e.g. 6.7 denier) Brush diameter: 25mm or more (e.g. 35mm) Fiber length: 4 mm or more (e.g. 8 mm).

[Brief explanation of drawings]

FIG. 1 shows a device according to the invention, FIG. 2 is a sketch of a protector magnet, and FIG. 3 is a cross-sectional view thereof. Codes in the figure: 1...Photosensitive drum, 2...Fur brush, 3...Flicker bar, 4...AC power supply, 5
...Protector magnet, 6...Erase lamp,
7... Toner box, 8... Magnetic toner, 9...
...Trimmer, 10a...Magnetic pole roll, 10b...
Sleeve, 11...bias power supply, 12...transparent plate.

Claims (1)

[Scope of Claims] 1. An erase lamp housed in a magnetic powder intrusion prevention device having magnets of the same polarity disposed in the opening is left between the cleaning fur brush and the developing and cleaning type magnetic roll. A cleaning device for electrophotographic copying machines. 2. The cleaning device for an electrophotographic copying machine according to claim 1, which uses a magnetic powder intrusion prevention device in which a transparent shielding plate is applied to the opening to protect the light source.