JPH0121319Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a cleaning device for an image forming apparatus;
More specifically, the present invention relates to a cleaning device for an image forming apparatus that is provided with auxiliary cleaning means.

In general, the process of image formation using an electrostatic recording device, for example, uses an insulator as a charge carrier or an insulating photoconductor, and an original is placed on top of the insulating material using an electrostatic recording needle or corona charging and light irradiation. An electrostatic latent image corresponding to the image is formed, and this latent image is developed with a toner developer containing thermoplastic colored fine powder as a main component, thereby forming a visible image.

The visible image, ie, the toner image, on the charge carrier is then transferred onto a copying material such as transfer paper. The toner image transferred onto the transfer paper by the above method is
The image forming process is completed by fixing the image onto the transfer paper using conventional heating means.

In the above image forming process, when the toner on the charge carrier is transferred onto a copying material such as transfer paper, the entire toner image is not necessarily completely transferred, so even after the transfer, the charge carrier remains A small amount of toner remains on the top.

Therefore, this residual toner must be cleaned before the charge carrier can be used for the next process. Conventionally, a brush cleaning method, a blade cleaning method, or the like has been adopted as a method for cleaning residual toner on a charge carrier.

Although each of these cleaning methods can effectively clean toner,
In order to reuse the collected toner, a separate device for reuse is required, which inevitably increases the size of the image forming apparatus itself and is not necessarily a desirable cleaning method.

Therefore, from the above point of view, an image forming apparatus using a two-rotation system is known as an apparatus developed for the purpose of downsizing and simplifying the apparatus.

In this two-rotation image forming process,
This relates to a method in which development and cleaning are performed in the same device during the image forming process, and the process is completed by rotating the charge carrier twice, and the process is completed by the first cycle of rotation of the drum having the charge carrier on the surface. The electrostatic latent image is developed with toner, and in the second rotation cycle, a small amount of toner remaining on the surface of the charge carrier is cleaned using the same developing device.

The developing device used in the two-rotation system is suitable for developing an electrostatic latent image by forming a magnetic brush with a developer made of magnetic toner containing magnetic powder or a developer made of magnetic toner and carrier. It is. Such a developing method using, for example, an insulating magnetic toner was disclosed in Japanese Patent Application Laid-open No. 1986-
This method is described in Japanese Patent No. 26046, and has various advantages not found in the prior art, such as a simple structure of the developing section, easy maintenance, and the ability to obtain sharp transferred images on plain paper.

FIG. 1 is a sectional view of a developing device A using the above developer. The developer falls from a hopper 1 into a toner retainer formed by a sleeve 2 and a rear wall 3 of the developer and is stored as toner 4. When the conductive and non-magnetic sleeve 2 that surrounds the fixed magnet group 5 with different polarity alternating arrangement is rotated clockwise, the toner 4 passes through the cutting plate gap 7 formed between the spike regulating plate 6 and the sleeve 2, and the toner 4 flows into the sleeve. 2, a thin layer corresponding to the cutting plate gap 7 is deposited on the sleeve 2. The toner 4 reaches the development gap 8 while standing on the sleeve 2 on top of each magnetic pole. Reference numeral 9 designates a conductive support member, for example, an aluminum drum, and in FIG. 1, only the circular arc of the drum in the developing section is omitted. 10, for example, zinc oxide provided thereon;
This is an electrophotographic photoreceptor made of selenium or an organic semiconductor as a charge carrier, and only the circular arcs are abbreviated. The developing gap 8 is the gap between the photoreceptor 10 and the sleeve 2. The developer is in the development gap 8.
The electrostatic latent image is brought into a fluffy state by the main magnet 11, contacts the photoreceptor 10, and develops the electrostatic latent image on the photoreceptor, which rotates clockwise. Note that a known method is used to create the electrostatic latent image.

Further, in the above development method, the support member 9, the sleeve 2, and the spike regulating plate 6 are grounded. Details of such a developing method are described in Japanese Patent Application Laid-Open No. 51-26046 and Japanese Patent Application Laid-Open No. 52-106734. In these two-rotation type image forming apparatuses, development is performed in the first cycle using the above-mentioned development method, and the toner image is transferred to the transfer material.
After the photoreceptor is neutralized, a cleaning cycle, which is a second cycle, begins.

In this cleaning cycle process, no charging or image exposure is performed, and only a cleaning step is performed, and the above-mentioned developing device A is used again for this cleaning action. That is, in the first cycle, main magnet 1
1, the amount of developer in a fluffy state on the sleeve 2 is consumed in the necessary amount for developing the electrostatic latent image on the photoreceptor 10. Developer 4 again
A small amount of toner remaining on the photoreceptor 10 is easily cleaned from the photoreceptor 10 by the magnetic force of the magnet group 5.

However, in these image forming devices, when cleaning the photoreceptor after transfer, toner that cannot be cleaned may remain.
These have the disadvantage that they later appear as development such as fog.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved cleaning device that can obtain cleaner toner images using an image forming apparatus that uses a two-rotation method. The above object is achieved by a cleaning device for an image forming apparatus which is provided with an auxiliary cleaning means consisting of a combination of a magnet and a brush in front of the corona charging device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cleaning device for an image forming apparatus according to the present invention will be specifically described below with reference to embodiments shown in the drawings.

FIG. 2 is an external view showing the structure of an electrostatic recording apparatus equipped with a cleaning device for an image forming apparatus according to the present invention.

Reference numeral 9 denotes a charge holding drum, on the surface of which a photoreceptor 10 as a charge holding body is stretched and rotates in the direction of the arrow. This photoreceptor 10 may be of any material as long as it can hold a charge as an electrostatic latent image on its surface, and is made by coating a photoconductive material such as selenium, zinc oxide, cadmium oxide, or an organic photoconductor on a support. Examples include a photoreceptor having an insulating material on a support, an insulator having an insulating material on a support, and the like.

12 is a corona charging device that uniformly charges the surface of the charge holding body 10 to generate a charge, and then an exposure device 13 exposes it imagewise to erase the charge on the exposed portion to form an electrostatic latent image. However, in some cases, an electrostatic latent image is formed by directly generating charges on the surface of the photoreceptor 10 in an imagewise manner using a means such as an electrostatic recording needle.

A is the same developing device as shown in FIG. 1, which functions as both developing and cleaning. The operation of this developing device A is as described above. The toner image developed by this developing device A is transferred to the transfer section 14 as the drum 9 rotates and is transferred to a transfer material P such as copy paper, but the transfer means is a corona discharge, a bias roller 15, etc. The transfer may be performed not only by an electrical method using a , for example, but also by a physical means such as pressing, and as the transfer material p, in addition to copy paper, for example, a belt-shaped intermediate transfer member may be used. good. After the toner image is transferred, the toner remaining on the photoreceptor 10 is electrically neutralized by the static eliminator 16 in the next step and reaches the auxiliary cleaning member 17 according to the present invention. The member 17 is movable up and down with respect to the surface of the photoreceptor 10, and in this first rotation cycle, the cleaning member 17 slightly escapes from the surface of the photoreceptor 10 and does not perform a cleaning action. The toner remaining on the surface of the photoreceptor 10, which has entered the second rotation cycle, is cleaned by the developing device A according to the process described above.

However, in such an image forming apparatus, when the photoreceptor 10 is cleaned, toner that cannot be cleaned may remain.
When this material enters the charging process later, it is attracted to the discharge wire and becomes contaminated, resulting in uneven discharge and uneven charging during development, so it is necessary to thoroughly clean it. Therefore, in the device according to the present invention, in order to completely clean the toner that could not be cleaned by the developing device A, a magnet and a brush are combined and constructed as an auxiliary cleaning means in a position in front of the corona charging device 12. It is characterized in that a cleaning member 17 is provided. That is, the toner on the surface of the photoreceptor 10 that has not been cleaned in the developing device A is completely cleaned in the second rotation cycle by the cleaning member 17 of the present invention in which the brush is brought into contact with the surface of the photoreceptor 10. Ru. This is because conventionally it was thought that it was impossible to completely clean away the thin toner remaining on the photoreceptor by using a magnet alone, even if a fairly powerful magnet was used. This is because the toner holding force due to the magnetic force of the magnet becomes stronger and complete cleaning can be achieved only when the toner lifting action by the brush is combined with the toner lifting action. In the inventor's experiment, 99
Even if % or more of the toner has been cleaned, a small amount of residual toner will be attracted to the discharge wire if several thousand copies are made, resulting in uneven charging as described above.
However, according to the present invention, the effect of returning untransferred toner to the developing device, which is an advantage of the two-rotation system, is carried out almost in the same way as in the conventional method, and only a very small amount of toner is collected by the auxiliary cleaning member. Since the amount of adhering toner is extremely small, the brush can remain stationary and does not need to be rotated. Thus, the photoreceptor 10
is provided for reuse.

FIG. 3 is an embodiment showing the external configuration of an auxiliary cleaning member according to the present invention.

The cleaning member 17 may be configured by combining the magnet 18 and the brush 19 by adhering them via an adhesive layer 20 using an adhesive, for example, but they may also be combined integrally, as long as the cleaning effect is not impaired. Any combination of configuration means may be used.

As explained in detail above, in the cleaning device according to the present invention, the cleaning member having the above-mentioned configuration is provided as an auxiliary means in front of the corona charging device, so that the advantages of the conventional two-rotation type image forming device are not lost. In addition, contamination of the discharge wire is prevented, and rotation of the brush is not required, so the photoconductor surface is not damaged, and it not only simplifies the device and improves durability, but also produces beautiful copies. The resulting device is useful.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device, FIG. 2 is an external view showing the configuration of an electrostatic recording device equipped with a cleaning device according to the present invention, and FIG. 3 is an external view showing the configuration of an auxiliary cleaning member according to the present invention. It is a diagram. 9... Charge retention drum, 10... Photoreceptor, 17
...Auxiliary cleaning member, 18...Magnet, 19...Brush, 20...Adhesive layer, A...
Developing device.

Claims (1)

[Scope of utility model registration request] 1. A cleaning device for an image forming device which uses a two-rotation system, characterized in that an auxiliary cleaning means made of a combination of a magnet and a brush is provided in front of a corona charging device.