JPS60150076A - Cleaning device - Google Patents

Abstract

PURPOSE:To remove various kinds of foreign matter stably for a long period by pressing an elastic cleaning roller against an image carrier, and allowing a scraper to abut on this roller at a 0-45 deg. acute angle. CONSTITUTION:A cleaning blade 21 made of urethane rubber, etc., is fitted to the housing 23 of a cleaning device 2, the elastic cleaning roller 3 consisting of an external layer 3a of solidstate silicone rubber and an internal layer 3b of silicone sponge is provided, and they are pressed against the image carrier 1. Then, the scraper 4 abuts on the roller 3 at a 0-45 deg. acute angle to the tangent to the roller 3. Consequently, various kinds of foreign matter such as residual toner, talc, and corona products are removed stably for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention This invention relates to an image forming apparatus using an electrostatic photographic process;
In particular, it relates to the cleaning device.

(2) Prior art and issues to be solved After forming a transferable image using toner on the surface of a moving image carrier and transferring this image to a transfer material mainly made of paper, residual toner remaining on the surface of the image carrier is removed. In image forming apparatuses where the process of removing is repeated, residual toner or minute pieces of paper generated from transfer material.

In order to stably obtain high-quality images, it is extremely important to sufficiently remove various foreign substances such as Merck and rosin that will precipitate, as well as corona products generated due to the presence of high-pressure corona generating parts in the image forming device. is important.

For this reason, a number of cleaning methods have been proposed that use an elastic cleaning roller using a fur brush, a web, a cleaning blade, a sponge, or the like.

Among these, those using a cleaning blade have been put into practical use in recent years because they have a simple structure, require little space, and have excellent cleaning functions.

However, although the cleaning blade that uses a cleaning blade has an excellent function of removing residual toner on the surface of the image carrier, it does not have the ability to remove foreign substances such as paper particles, precipitates such as rosin and talc, or corona products as described above. There is a risk that these deposits, not necessarily light components, may absorb moisture in the environment, leading to a decrease in the surface resistance of the image carrier and, thereby, to disturbance of the electrostatic latent image.

Furthermore, as a cleaning means, it is already known that sponge rollers are used, especially in image forming apparatuses using liquid developer, but if such a cleaning means is used in image forming apparatuses using powdered toner, Although it is effective in removing foreign matter such as, toner spills and contaminates the inside of the device, and the sponge becomes clogged, resulting in rapid deterioration of the cleaning action, making it impractical.

In addition, there are known image forming apparatuses using a dry developing system that utilize elastic rollers to prevent toner from falling off the cleaning device (for example, US Pat. No. 3,838,472); It goes without saying that such a device does not have the function of removing various kinds of foreign matter, and if an attempt is made to remove foreign matter by pressing the elastic roller against the image carrier, the drive system will be overloaded. This may cause image blur due to vibration.

Furthermore, there have been proposals to mix an abrasive such as CeO2 into the toner, or to form a magnetic brush and use it to rub the surface of the image bearing member at the cleaning site, but these methods do not provide stable cleaning over a long period of time. In order to perform the action, many of them still lack stability of action, and a satisfactory result has not yet been obtained.

(3) Purpose of the Invention The present invention has been made to solve the above-mentioned situation, and provides an elastic cleaning roller for at least pressing against the surface of an image carrier to remove various foreign substances as mentioned above. The cleaning device has a contact point with the cleaning roller on the same level as or slightly below the central axis of the cleaning roller on the opposite side of the cleaning roller from the image carrier, and the cleaning roller at the contact point By providing a scraper whose angle with the tangent to the surface is a moderately acute angle, foreign matter such as paper dust and corona products can be removed well, and
The object of the present invention is to provide a cleaning device that reduces wear on an elastic roller and prevents toner from adhering to the surface of the elastic roller, thereby making it possible to maintain and stabilize the cleaning function over a long period of time. It is.

(4) Structure and operation of the invention In order to solve the above-mentioned problems, in the present invention, at a fixed position on the surface of a moving image carrier, a low-hardness elastic material is installed in a cleaning device disposed close to the surface of the moving image carrier. An elastic cleaning roller having an inner layer made of an elastic material and an outer layer made of a highly hard elastic material is disposed so as to have a relative speed with the image carrier, and the image carrier abuts the cleaning roller near a position diametrically opposed to the image carrier. In addition, the scraper is arranged so that the angle formed with the tangent line (actually, the tangent plane) of the cleaning roller at the relevant contact position is an acute angle, preferably in the range of 0° to 45°, and the scraper is configured to remove foreign matter as described above. At the same time, the surface of the cleaning roller is maintained in a suitable condition to obtain a stable cleaning function over a long period of time.Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side sectional view of a main part showing the case where the present invention is applied to an electrostatic copying machine, in which a cleaning device 2 is arranged parallel to the axis of an image carrier 1 formed in a cylindrical shape that rotates in the direction of the arrow. are placed close together.

In addition, around the human face of the image carrier, a charging means for uniformly charging the photoconductive layer on the surface of the image carrier, an exposure means for projecting a light image onto the photoconductive layer to form an electrostatic latent image, and a charging means for forming an electrostatic latent image by projecting a light image thereon, and a charging means for uniformly charging the photoconductive layer on the surface of the image carrier; A developing means for producing a transferable image, a means for transferring the developed image onto a transfer material, etc. are provided, but since these are not directly related to the present invention, a description thereof will be omitted.

The cleaning device 2 has a housing 23, to which a cleaning blade 21 made of an elastic material such as urethane rubber is attached by an appropriate means, and the edge of one edge of the grade is attached to an image carrier. It is designed to remove residual toner by pressing against the surface.

An elastic cleaning roller 3 is rotatably disposed upstream of the cleaning blade when viewed in the running direction of the image carrier, and rotates at a constant relative speed to the image carrier. The cleaning roller consists of an outer layer 3a made of solid silicone rubber and an inner layer 3b made of silicone sponge, and its hardness is 2.
0 to 40 degrees (ASKFJRC constant load 500 J') is used, and is pressed against the surface of the image carrier so that the nip width N is 1 to 6 mm. Further, the peripheral speed of the cleaning roller is preferably in the range of 50 to 300% of the surface peripheral speed of the image carrier.

Along with the toner scraped off by the cleaning blade 21, foreign substances such as paper dust and corona products removed by the cleaning roller 3 are conveyed as the cleaning roller rotates, and are further scraped off by the scraper 4 in contact with the roller. The waste toner is then transported to a waste toner storage section inside the housing, and further, if necessary, to a waste toner collection container outside the housing by a screw conveyor 22 extending perpendicularly to the plane of the paper.

The scraper 4 is formed of an insulating material such as mylar film, and its free edge is located at a position approximately facing the image carrier of the cleaning roller 3 in the diametrical direction, and is horizontally at the same height or slightly below the central axis of the roller. The contact point is in contact with the cleaning roller at a position of 0° to 45°, preferably 0° to 2° with respect to the cutting line to the cleaning roller at the contact point.
It shall be arranged at an angle within the range of 0.

As shown schematically in Fig. 2, the angle between the scraper and the cutting line to the cleaning roller 3 and the scraper 4 at the contact position is θ, and experiments were conducted by varying θ, and the following results were obtained. Obtained. In actuality, the leading edge of the scraper was bittened by an elastic cleaning roller with a depth of 0.1 to 51A, and a Mylar film having a thickness of 190 to 200 .mu.m was used as the scraper.

In the case of θ-90°= scrape spring failure occurred after about 50 sheets were passed. This is because waste toner accumulates on the edge of the scraper, and because of the amount of M, and also because the edge tends to move away from the roller surface as the roller rotates, it is possible for the edge to separate from the roller. It was the cause.

In the case of θ-60°: Toner fusion occurred at the edge of the scraper after about 100 sheets were passed, and the surface of the cleaning roller was scraped after about 500 sheets were passed, resulting in poor scraping.

This is the edge of the scraper However, with the cleaning roller Localized inversion by rubbing Do you think it's because I woke you up? '1. -Many.

When θ=30°: A phenomenon similar to the above case when θ=600 occurred locally.

This goes to the scraper roller The abutting edge of The condition is not uniform, and the unevenness is more than 2. Because there are weak parts, some is substantially the same as in the previous case. This will result in a situation where this part is It is thought that a rotational phenomenon occurs. It will be done.

When θ=0°: No scraping defects occurred even after passing 100,000 sheets.

The end of the scraper after passing 120,000 sheets The edges are peeled off and the edges are scraped. The problem with the pull-up is starting to become noticeable. This is due to the wear of the scraper. Look at myra film scraper This is thought to be the limit of its lifespan.

Note that even though θ=0°, Using mylar film la for rapa Cleaning roller surface as mentioned above It has a certain biting amount as Therefore, it is actually 2 to 3 degrees. Ru.

If θ>90°, the scraper is facing in the same direction as the rotation direction of the cleaner blade.
Theoretically, this is considered to be lacking in the function of guiding and transporting the collected toner and other substances, and it is thought that the toner and other foreign substances will tend to stick to the surface of the cleaning roller. It is easy to understand that there is no such angle.

In view of the above experimental results, the angle θ is an acute angle, especially 00
Depending on the degree of processing and strength of the tip edge of the scraper, it is particularly preferable to set the angle in the range of 00 to 20 degrees.

Although the cleaning roller Kld in the above embodiments was made of silicone rubber or silicone sponge, it goes without saying that the roller is not limited to these.
Any material may be used as long as it is solid, has an outer layer of high hardness and an inner layer of low hardness, and has appropriate elasticity as a whole.

Further, as the material of the scraper, a thin plate made of bronze, stainless steel, etc., which emphasizes scraping action, may be used.

(5) Effects As explained above, the present invention has a structure in which an elastic cleaning roller is pressed against the image carrier and a scraper is arranged in contact with the cleaning roller at an acute angle. Rosin.

Not only can it effectively remove various foreign substances such as precipitates such as talc and corona products, but it also removes foreign substances that have been transferred to the cleaning roller without damaging the second surface of the Ri+)-Nino Glora for cleaning. Since it is possible to maintain functionality, it is possible to prevent deterioration of image quality due to poor cleaning and to obtain stable hard copies over a long period of time without increasing maintenance costs.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of essential parts of a cleaning device according to the present invention, and FIG. 2 is an explanatory diagram showing the relative arrangement of a cleaning roller and a scraper pan. 1... Image carrier, 2... Cleaning device, 21...
-Cleaning blade, 3...Cleaning roller, 4...Scraper. Figure 2

Claims (1)

[Claims] An elastic cleaning roller that comes into pressure contact with the surface of the moving image carrier, and a tip edge that comes into contact with the cleaning roller. A cleaning device comprising an extended and supported scraper.