JPH065441B2 - Cleaning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrophotographic copying machine, and more particularly to a cleaning apparatus therefor.

(Problems to be solved with conventional technology) After a transferable toner image is formed on the surface of a moving image carrier, this is transferred to a transfer material, and at this time, residual toner and other foreign matter remaining on the surface of the image carrier are removed. In a known image forming apparatus that repeats the removing process, it is an essential requirement to obtain a stable image by sufficiently removing the residual toner and other foreign substances each time.

As a cleaning means of this kind, a cleaning blade made of an elastic material such as urethane rubber has been widely used conventionally because of its simple structure and excellent toner removing function.

However, the substance to be removed from the surface of the image carrier is not only the residual toner but also the corona product generated by the presence of the high-pressure member in the image forming apparatus and the paper mainly used as the transfer material. There are various deposits such as rosin, talc, etc. If these foreign substances adhere to the image carrier, they will absorb moisture in a high humidity and the portion will have low resistance, which may adversely affect the image forming apparatus. It was

Moreover, it has been difficult to sufficiently remove the above-mentioned foreign matters by the above-mentioned cleaning blade.

For this reason, as a cleaning means, in addition to the above-described cleaning blade, a roller made of an elastic material such as silicone rubber urethane is arranged in the vicinity of the cleaning blade, and the roller is configured to press-contact and rub the surface of the image carrier. Already proposed.

As the elastic rubbing roller as described above, for example, the surface of a silicon sponge is coated with a solid silicone rubber,
If the hardness is 20-40 (ASKER C constant load 500g _r ),
For example, when pressing against a rotating cylindrical image carrier, the nip width during pressing is set to 1 to 4 mm, and the peripheral speed of the rubbing roller at both contacting portions is set to 50 to 300% of that of the image carrier. At times, it has been found that good results can be obtained in removing foreign matter as described above.

By using the cleaning blade and the elastic rubbing roller in this way, the function of removing the residual toner and other foreign matter on the surface of the image carrier is improved, but the structure of the relevant part of the cleaning device becomes complicated accordingly. Therefore, there is a possibility that inconvenience may occur in processing the toner and the like removed from the image carrier by the blade and the rubbing roller.

This will be described with reference to FIGS. 3A and 3B. These drawings are partial front views of the portion where the cleaning blade and the elastic sliding roller are in contact with the image carrier, as viewed from the image carrier side. An elastic rubbing roller 10 rubs an image carrier (not shown) running in a direction substantially parallel to the arrow A with an appropriate nip width 10c, and a cleaning blade disposed downstream thereof. One edge 9a of 9 is in pressure contact with the surface of the image carrier.

A sealing material 13 is provided on the side of the cleaning blade 9 and the rubbing roller 10 for preventing scattering of the removed toner and the like.
Are arranged on both sides (only one is shown in the figure).

In such a structure, as shown in FIG. 3A, the width of the rubbing roller 10 (the length when viewed in the left-right direction, the same applies hereinafter) is larger than that of the cleaning blade, or both are close to each other. Then, the toner removed from the image carrier may enter the gap 15 between the end of the blade 9 and the sealing material 13 and may be scattered outside the cleaning device to contaminate each part inside the image forming device. .

Further, as illustrated in FIG. 3B, when the width of the cleaning blade 9 is made larger than that of the rubbing roller 10, the toner is not sufficiently collected in the portions 16 near the both ends of the blade, and the image of the blade edge of this portion is formed. The friction with the carrier was so large that the blade was turned up and cleaning failure could occur.

The present invention has been completed in view of such drawbacks, and the width of the cleaning blade width, the width of the rubbing roller, and other members related to the processing of the removed toner and the like is appropriately determined as described above. It is an object of the present invention to provide a cleaning device that can effectively avoid various drawbacks.

(2) Configuration of the Invention (Technical Means and Actions for Solving Problems) In order to achieve the above object, in the present invention, a cleaning blade and an upstream side of the blade as viewed in the traveling direction of the image carrier. In a cleaning device having at least one elastic rubbing roller arranged and a scraper for removing toner and the like adhering to the roller, the scraper width is shorter than that of the rubbing roller and the width of the rubbing roller is cleaned. The feature is that it is shorter than that of the blade.

With this configuration, the toner and the like removed from the surface of the image carrier is guided to both ends of the cleaning blade in an appropriate amount, and the toner is scattered outside the cleaning device or insufficient at both ends of the cleaning blade. It is possible to obtain a stable cleaning action by preventing the cleaning.

(Explanation of Examples) Hereinafter, a case where the present invention is applied to a copying machine having a rotating cylindrical photoconductor will be described with reference to the accompanying drawings.

FIG. 1 is a schematic side view of a main part of a copying machine to which the present invention is applied. After the surface photoconductive layer of a cylindrical photoreceptor 1 rotating in the direction of arrow A is charged by a charger 2, The light image 3 of the document is irradiated to form an electrostatic latent image. Then, toner is supplied to the latent image from the developing device 4 to form a transferable toner image, and the toner image is transferred onto a transfer material that is separately conveyed from the conveying path 5 at a transfer portion including a transfer charger 6. .

The transfer material is then separated from the photoconductor 1 by the action of the separation charger 7a and the separation roller 7b, and reaches the fixing portion (not shown) via the conveyance path 7c.

On the other hand, the toner sticking to the surface of the photoconductor without contributing to the transfer at the transfer portion reaches the cleaning device 8 together with the various foreign matters as described above.

The cleaning device 8 is provided with a cleaning blade 9 for scraping off the residual toner. Further, in the illustrated embodiment, the above-mentioned elastic rubbing roller 10 on the upstream side thereof is brought into pressure contact with the photoconductor 1. Rubbing. The rubbing roller comprises an inner layer 10b made of silicone sponge and an outer layer 10a made of solid silicone rubber.
In addition, it is assumed that the above-mentioned configuration and operation are provided.

The toner and other foreign matter removed from the surface of the photoconductor by the rubbing roller 10 and the cleaning blade 9 adheres to and accumulates on the surface of the rubbing roller, is conveyed along with the rotation, and is scraped off by the scraper 11. It is accumulated in the storage part in the cleaning device and is discharged to the outside by the screen conveyer 12 as needed.

In such a copying machine, in this embodiment, the widths of the cleaning blade 9, the rubbing roller 10 and the scraper 11 are set as follows.

FIG. 2 shows the relationship among the above three members as seen from the direction of arrow B in FIG. 1, in which the width of the cleaning blade 9 is 3 to 1 at both ends than the width of the rubbing roller 10.
The width of the scraper 11 is made 5 mm longer, and the width of the scraper 11 is made shorter than that of the rubbing roller by 1 to 5 mm at both ends.

With such a configuration, the thickness of the toner on the scraper is 30 μ or less in the range in which the scraper is in contact with the rubbing roller, while it is about 20 μ in the scraper non-contact portions on both ends. The excess toner is conveyed to the photoconductor and reaches the position of the cleaning blade, and due to the action of the edge, the excess toner is diffused to the voids 17 on the outer sides of both sides. In this case, the width relationship between the above-mentioned respective members is set to an appropriate numerical value by the toner scraping function of the cleaning blade 9 and the scraper 11, the toner rubbing removal action of the rubbing roller 10, the toner characteristics, and the like. ,
It is extremely easy to carry out experimentally to prevent the toner diffused by the blade edge from being removed by the portion and reaching the gap 15 between the blade and the seal member 13.

As described above, the cleaning blade 9 and the rubbing roller 10
By determining the dimensional relationship of the scraper 11 and the scraper 11, an appropriate amount of toner is supplied to the cleaning blade portion without being removed at the rubbing roller portion, and the disadvantages such as curling due to lack of toner at both ends of the cleaning blade are not caused. Moreover, it is possible to effectively prevent the toner from escaping from the gap portion to the outside.

Next, the relationship between the width of the cleaning blade and the width of the rubbing roller and the width of the developing area and the image area of the surface of the photoconductor will be described.

As is well known, since the toner adhesion area supplied by the developing device 3, that is, the developing area width is larger than the width of the transfer material, that is, the image area width, there is no transfer leakage. Outside the both sides of the image area, there are formed non-image areas in which the photoconductor runs with some toner attached.

On the other hand, as for the rubbing roller, as described above, it is always preferable to use silicone rubber.
It is known that if there are many unreacted components in the rubber, they may seep to the surface of the roller and adhere to the photoconductor, causing disturbance of the electrostatic latent image, contamination of the transfer material, and other deterioration of the image. . In order to avoid such an inconvenience, it is preferable to use urethane rubber. However, when urethane material is used, the blade edge in the cleaning device causes the toner to move in the lateral direction only by the above-mentioned dimensional relationship. Diffusion may be insufficient.

In such a case, in addition to the dimensional relationship of each member described above, the width of the rubbing roller is set to be between the maximum developing width and the maximum image width, and the toner in at least a part of the non-image area is set. It is preferable to avoid the toner shortage state at both ends of the blade by directly arriving at the cleaning blade edge.

(3) Effects of the Invention In the cleaning device used in the image forming apparatus of the present invention, the width of the cleaning blade for removing the residual toner and other foreign matters, the elastic rubbing roller, and the width of the scraper for removing the toner and the like from the roller can be reduced. By establishing an appropriate relationship, the toner is supplied over the entire width of the cleaning blade to prevent the blade from curling up due to lack of toner and cleaning failure due to this, and excessive toner is supplied to both sides of the blade. Since it can be prevented from being scattered to the outside of the cleaning device, a stable cleaning function can be maintained for a long period of time, which contributes to obtaining a high-quality image.

[Brief description of drawings]

FIG. 1 is a schematic side view of a main part of a copying machine to which the present invention is applied,
FIG. 2 is a front view of a main portion showing a relational arrangement of a cleaning blade, a rubbing roller and a scraper, and FIGS. 3A and 3B are partial front views showing a well-known relational arrangement of a cleaning blade and a rubbing roller. . 1 ... Photosensitive member, 3 ... Developing device, 8 ... Cleaning device, 9 ...
Cleaning blade, 10 ... rubbing roller, 11 ... scraper, 13 ... sealing member, 15 ... gap

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Keishi Osawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Innovator Nobutoshi Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non non corporation

Claims (2)

[Claims] 1. A cleaning blade that comes into pressure contact with the surface of an image carrier, an elastic rubbing roller that rubs against the surface, and a scraper that abuts against the rubbing roller, and the axial direction of the rubbing roller. The length of the cleaning blade in the same direction and the length of the scraper in the same direction are shorter than the length of the cleaning blade. 2. The cleaning device according to claim 1, wherein the axial length of the rubbing roller is smaller than the maximum developing area width and larger than the maximum image area width.