JPH0328445Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic copying device, and more specifically, an electrophotographic copying device in which a cleaning device for cleaning residual toner on a charge carrier is improved. Regarding.

[Background of the idea]

Generally, the image forming process using an electrophotographic copying device involves forming an electrostatic latent image corresponding to the image of an original on a charge holding body using an insulating photoconductor as a photoreceptor through corona charging and light irradiation. A visible image (toner image) is formed by developing this with a toner developer whose main component is thermoplastic colored fine powder. The toner image on the charge carrier is electrostatically transferred onto a transfer material such as plain paper and fixed for use. On the other hand, residual toner is removed from the charge holding member by a post-transfer cleaning means, and the charge holding member is prepared for the next copy image formation.

Here, as a method for cleaning the residual toner on the charge holding body after the above-mentioned transfer, conventionally,
Fur brush methods, web methods, blade methods, roller methods and magnetic brush cleaning methods are known. The fur brush method is a method in which a fur brush that rotates at a relatively high speed is brought into contact with a charge carrier for cleaning, and the toner removed by the cleaning is sucked in by a suction to collect the toner on a filter box. Although this method is satisfactory in terms of cleaning ability, it has drawbacks such as the large size of the device and the generation of noise, so it is not used much at present.

Other methods do not use suction and therefore do not have the drawbacks of the fur brush method described above. In particular, blade cleaning devices have the advantage of having a simple structure and being compact, and are widely used.

However, since all cleaning methods other than the fur brush method involve rubbing and removing the toner on the charge carrier, some of the toner, which is a powder with a particle size of more than 10 microns, becomes atomized during cleaning. It hangs and floats in the air. This floating toner is present in the electrostatic recording device and has an adverse effect on copy image formation or image quality. In order to prevent the toner floating in the form of mist from spreading inside the electrostatic recording apparatus, the cleaning means is provided in a sealed box to prevent the toner from flowing out. However, it is difficult to completely cover the cleaning means with this closed box, and some space is required between the rotating drum-shaped charge holding body and the outer wall member of the closed box. Conventionally, efforts have been made to make this gap as narrow as possible or to lengthen the gap to create a structure that prevents mist-like floating toner from leaking along this gap to the outside of the cleaning device, but in reality, leakage does not occur. contamination of the outside world was unavoidable. This is due to the fact that as the drum-shaped charge carrier rotates, the air layer adhering to the surface of the charge carrier enters the airtight box-shaped cleaning device, so the air pressure inside this sealed box-shaped cleaning device is slightly reduced. becomes higher than the outside, and this amount of air flows out along the gap, and this seems to be because the floating toner also flows out at the same time.

[Purpose of invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic copying apparatus equipped with a cleaning device that prevents the air pressure inside the cleaning device from becoming higher than that outside the cleaning device and prevents toner from flowing out of the cleaning device.

[Structure of the invention] The above object is to perform image exposure on a photoreceptor drum by providing a document table on the upper surface and a slit exposure optical system below it, and to provide a cleaning device on the side surface of the photoreceptor drum to clean the photoreceptor. In an electrophotographic copying machine that performs blade cleaning on the circumferential surface of the drum and is provided with a motor fan to exhaust air from inside the copying machine, the top outer wall of the cleaning device is provided with an air hole portion equipped with a filter. A bottom cover is provided on the bottom surface of the slit exposure optical system, and the bottom cover and the top outer wall are substantially parallel and form an air passage therebetween, and the air flow generated in the air passage by the operation of the motor fan. This is achieved by an electrophotographic copying apparatus characterized in that the air in the cleaning device is sucked through the filter.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a cross-sectional view of the internal structure of an electrophotographic copying machine equipped with the cleaning device of the present invention. An image exposure section that exposes an original image is located above the photosensitive drum 1 that is rotationally driven in the direction of the arrow. That is, the original placed on the original platen 2 is subjected to slit exposure by optical scanning and image exposure. The slit exposure optical system 3 includes an exposure lamp 4
and a first movable base 6 on which a first mirror 5 is mounted, and the reflected light of the first mirror 5 is 1/1/2 of the first movable base 6.
The light is reflected by the second and third mirrors 8a and 8b of the second movable base 7, which moves synchronously with this at a speed of 2, and is incident on the lens 10. This lens 10 forms an original image on the circumferential surface of the photosensitive drum 1 via the fourth mirror 9 .

The photosensitive drum 1 rotating clockwise is first uniformly charged by a charging electrode 11, and then a latent image is formed by a slit exposure optical system 3. Photosensitive drum 1
The upper latent image is developed into a toner image when passing through the developing device 12.

A transfer electrode 13 and a separation electrode 14 are provided at the bottom of the photoreceptor drum 1, and a toner image is transferred to the transfer paper conveyed from the right paper feeder 15 at the transfer electrode 13, and then to the separation electrode. 14
After being separated at , the image is sent to the fixing device 17 by the conveyance device 16, where it is fixed, and then discharged from the device.

On the other hand, the photosensitive drum 1 to which a small amount of residual toner has adhered after the transfer is cleaned by the cleaning device 18 according to the present invention.

The electrophotographic copying apparatus described above includes many heat sources such as the fixing device 17 and the exposure lamp 4 within the apparatus. Therefore, when the apparatus is used continuously for a long period of time in a closed structure, the temperature inside the apparatus rises, and the performance of the photoreceptor drum 1 using, for example, selenium as the photoreceptor is significantly deteriorated. Therefore, an exhaust motor fan 1 is installed in the electrophotographic copying machine.
9 is provided to exhaust the internal air to the outside. The arrow A indicates motor fan 19.
This is the airflow caused by the

FIG. 2 shows a cleaning device 18 used in the electrophotographic copying apparatus of the present invention, in which an elastic blade 181 is used to clean the photoconductor drum 1, which rotates in the direction of the arrow. The blade material is made of synthetic rubber such as urethane or silicone, or natural rubber. The residual toner scraped off by the elastic blade 181 falls on the collection blade 182 and is collected in a toner reservoir 183. The toner accumulated in the toner reservoir 183 is conveyed and collected in one direction by a rotating spiral screw 184. 185 is the outer wall, outer wall 1
85 to prevent the toner surrounded by the toner from scattering to the outside. Further, there are gaps 186a and 186b between the outer wall 185 and the rotating photoreceptor drum 1.

The present invention includes a bottom cover 30 of the optical system that covers the slit exposure optical system 3 and has a dust-proof effect, and an upper outer wall 185a that forms the upper surface of the cleaning device 18 located almost parallel to the bottom cover 30 of the optical system. It is provided in an air hole 188 covered by a filter 187 made of fiber or the like, and the above-mentioned parallel bottom cover 30 and top outer wall 18
5a forms a chimney-like air passage,
The motor fan 19 is rotated to form an air flow at an appropriate speed, and air is sucked from inside the cleaning device through a filter 187.

With this structure, the mist-like floating toner that flowed out from the gap 186b and the like in the prior art is prevented from flowing out. This seems to be because the slightly higher pressure air inside the cleaning device 18 flows through the air hole portion 188 and flows out through the filter 187 toward the air flow. This was demonstrated by the fact that the filter 187 became smeared with toner after long periods of copying. At the same time, the present invention was also found to be effective in significantly reducing toner scattering within the electrostatic recording device.

In this embodiment, the airflow from a motor fan, which happens to be provided for the purpose of preventing an overall temperature rise inside the electrophotographic copying machine, is used, but a separate motor fan for cooling the photosensitive drum is newly provided.
It is also possible to create an air flow between the bottom cover 30 and the upper outer wall 185a that forms the upper surface of the cleaning device 18, and the air flow is effective as an air vent hole provided with a filter. Both are included in this invention.

[Effect of idea]

The electrophotographic copying device of the present invention slightly reduces the pressure inside the cleaning device by extremely gentle means using airflow passing over the top surface of the cleaning device, thereby preventing toner from scattering outside the cleaning device. This is what I did. Conventionally, there has been a device that uses a direct suction fan to suck out toner floating in the cleaning device, but in this case, an unnecessarily large amount of toner adheres to the filter, and the filter often needs to be replaced.

The present invention has the excellent effect of eliminating such drawbacks and preventing leakage of toner from the cleaning device by means of a motor fan provided in the electrophotographic copying apparatus separate from the cleaning device.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of an electrophotographic copying apparatus according to the present invention, and FIG. 2 shows a cross-sectional view of the internal structure of a cleaning device provided in the electrophotographic copying apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 3... Slit exposure optical system, 18... Cleaning device, 30... Bottom cover, 181... Elastic blade, 182... Collection blade, 183... Toner reservoir, 184... Spiral Skrill, 185... Outer wall, 187...
Filter, 188...Air hole portion, 185a...Top outer wall.

Claims (1)

[Claims for Utility Model Registration] A document table 2 is provided on the upper surface and a slit exposure optical system 3 is provided below it to perform image exposure on the photoreceptor drum 1, and a cleaning device 1 is provided on the side surface of the photoreceptor drum 1.
8 is provided to remove the blade 1 on the circumferential surface of the photoreceptor drum 1.
In the electrophotographic copying apparatus, a motor fan 19 is provided to exhaust air from the inside of the copying apparatus, and a filter 1 is installed on the top surface of the cleaning device 18.
Upper outer wall 1 provided with air holes 188 marked 87
85a, a bottom cover 30 is provided on the lower surface of the slit exposure optical system 3, the bottom cover 30 and the upper outer wall 185a are substantially parallel to form an air passage therebetween, and when the motor fan 19 operates, the The air flow generated in the air passage causes the filter 187 to
An electrophotographic copying apparatus characterized in that the apparatus is configured to suck air from the cleaning device 18.