JPS6197679A - Cleaning device - Google Patents

Abstract

PURPOSE:To remove effectively remaining toner and foreign matters, such as rosin, talc, etc,, providing rollers which control the position between an elastic cleaning roller and phtosensitive body at both end sections of the cleaning roller coaxially with the cleaning roller. CONSTITUTION:A cleaning roller 22 is brought into pressure-contact with and slid on a photosensitive body 1, with a prescribed nip width (a) being controlled, by means of controlling rollers 23 provided at both end sections of the roller 22 coaxially with the roller 22. Moreover, a toner layer is formed by means of a scraper 24 provided on the roller 22 by leaving a clearance (d) between them. Since the nip width is properly controlled, not only remaining toner but also foreign matters, such as rosin, talc, etc., can be removed effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Scope of Industrial Application] The present invention relates to an image forming apparatus using an electrostatic photographic process, and particularly to a cleaning apparatus for the image forming apparatus.

[Prior art and problems to be solved by the invention] A process of forming a transferable toner image on the surface of a moving image carrier, transferring it to a transfer material, and then removing residual toner remaining on the surface of the image carrier. Many methods have been proposed as toner cleaning means for image forming apparatuses that repeatedly perform toner cleaning, but one method involves scraping off residual toner by pressing a cleaning blade made of an elastic material such as urethane rubber against the image bearing surface. Such devices have been widely used in practice because of their simple construction and good toner removal efficiency.

However, although this type of cleaning blade type has an excellent toner removal function, paper dust is generated from the transfer paper by repeatedly bringing the transfer material, which is usually paper, into contact with and separating from the image carrier. If rosin or talc deposited from the paper or corona products generated due to the presence of high-pressure parts in the device adhere to the surface of the image carrier, these foreign substances can be easily removed with a cleaning blade alone. Furthermore, there is a risk that these foreign substances may absorb surrounding moisture, lowering the surface resistance of the image carrier and disturbing the electrostatic latent image.

In order to avoid such problems, a structure has been proposed in which a porous elastic roller such as a sponge is brought into pressure contact with the image bearing surface (Japanese Patent Application Laid-Open No. 5-111)
5-100585), in order to remove the toner that has been removed from the image carrier surface and moved to the elastic roller, the elastic roller comes into direct contact with the image carrier surface in order to bring the scraper into contact with the elastic roller. There are problems in that the elastic roller and the scraper may be damaged, or depending on the materials of the elastic roller and scraper, frictional charging may occur, which may disturb the electrostatic m-image on the surface of the image carrier.

Furthermore, a method has been proposed in which a magnetic roller is disposed upstream of the cleaning roller, and the surface of the image carrier is rubbed by a magnetic brush formed by the magnetic roller.

Figure 1 shows an example of the above-mentioned means (Japanese Unexamined Patent Publication No. 57-104
970), which is a cleaning device 2 disposed close to an image carrier 100 rotating and traveling in the direction of arrow A.
00 is equipped with a cleaning blade 201,
This is pressed against the surface of the image carrier, and a magnetic roller 202 is placed on the upstream side at a distance of 0.8 mm from the surface.
is rotatably arranged, and a scraper 203 is placed at a suitable location to scrape the surface of the magnetic roller by 0.3 to 0.7 mm.
It is profitable to separate the distance between the two. With this structure, the toner removed from the image carrier forms a magnetic brush, thereby removing foreign matter from the surface of the image carrier. However, although this method of rubbing with a magnetic brush can remove things like paper dust, it cannot remove things that strongly adhere to the surface of the image carrier, such as rosin, talc, and corona products. was not very effective. In addition, the scraper also has a 0.3 to 0.7
Since the paper particles are spaced apart by mm, paper powder smaller than that size passes through, and it is impossible to prevent foreign substances such as rosin and talc from depositing on the surface of the image carrier.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned current situation, and includes a cleaning device for an image forming apparatus that uses a cleaning blade. It is an object of the present invention to provide a cleaning device which can effectively remove not only residual toner but also foreign substances such as rosin and talc by disposing an elastic cleaning roller that rubs.

〔Example〕

In order to achieve the above object, in one embodiment of the present invention, a cleaning blade disposed in a cleaning device disposed close to the surface of a moving image carrier made of an organic semiconductor is brought into pressure contact with the surface of the image carrier to remove residual particles. Toner! !
In addition, an elastic cleaning roller made of a non-magnetic material is arranged on the upstream side of the cleaning blade when viewed in the running direction of the image carrier, and is applied to the surface of the image carrier through a regulating roller to a predetermined nip width. The cleaning roller is rotated at a relative speed in the same direction or in the opposite direction on the photoconductor while being pressed against the surface of the photoconductor, and a scraper is provided on the cleaning roller with a small gap between the cleaning roller and the photoconductor. A thin layer of toner is formed on the surface of a rotating cleaning roller, and in this state, the roller is brought to a position where it is brought into pressure contact with an image bearing surface.

With this structure, the elastic cleaning roller comes into contact with and rubs against the surface of the image carrier, which removes paper dust, rosin, etc.
Foreign matter such as talc or corona products can also be effectively removed from the surface.

The gap between the elastic cleaning roller and the scraper is 5
It is best to keep the cleaning roller below 0. Since the gap is small, any paper particles removed by the roller can be reliably removed by the scraper, so most of the foreign matter will be on the surface of the elastic cleaning roller beyond this point. A thin layer of non-existent toner is formed, and in this state the roller surface comes into pressure contact with the image carrier, so that the lubrication effect of the toner prevents the cleaning roller from damaging the image carrier surface.

FIGS. 2 and 3 show an embodiment in which the present invention is applied to a copying machine equipped with a rotating cylindrical image carrier, in which a photoconductive layer is provided on the surface of the image carrier around the image carrier. A charging means for charging the electrostatic latent image, an exposing means for forming an electrostatic latent image by irradiating it with a light image, a developing means for making the latent image visible, a transfer means for transferring the developed toner image onto a transfer material, etc. However, since these are not directly related to the present invention, their explanation will be omitted.

Residual toner that is not transferred to the transfer material at the transfer site and remains on the surface of the image carrier is brought to the cleaning device WI20 position while remaining attached to the surface of the image carrier traveling in the direction of arrow A, together with paper dust and other foreign matter. .

The cleaning device 12 has a casing 25 extending substantially parallel to the axis of the image carrier l (in a direction perpendicular to the plane of the paper), and a cleaning blade 21 made of an elastic material such as urethane rubber is attached to the casing 25 as appropriate. The edge of one end of the image carrier is in pressure contact with the surface of the image carrier.

Inside the housing 25, a cleaning roller 22 made of a non-magnetic elastic material is attached rotatably in the direction of arrow B on the upstream side when viewed in the traveling direction of the image carrier.
A part of the surface thereof is in pressure contact with the surface of the image carrier with a predetermined nip width. It is effective to use sponge-like silicone rubber as the cleaning roller.
Nr! There are 4.

Further, as shown in the figure, a scraper 24 is disposed on the housing opposite the cleaning roller 22, and the distance #d between the scraper and the surface of the cleaning roller is maintained at 50 mm or less. Therefore, foreign matter such as paper dust attached to the surface of the cleaning roller is reliably removed by the scraper 24, and eight layers of toner free of paper dust are formed downstream from the scraper position in the running direction of the reroller 22. Since the roller surface rubs against the image carrier, the toner acts as a lubricant and prevents the image carrier surface from being damaged by the cleaning roller.

Regulation of the contact pressure between the cleaning roller and the surface of the image carrier will be described below.

As shown in FIG. 2 and a part of FIG. 3, the shaft 22a of the cleaning roller 22 is attached to the housing 25 via a bearing 26, and the cleaning roller 23 is attached to the shaft 22m directly or through a bearing 27 for cleaning. Regulations 20 are attached to both ends of the roller 22, and come into contact with the image carrier l to regulate the amount of entry δ of the cleaning roller 22 into the image carrier l. By regulating the amount of penetration δ, it is possible to regulate the contact pressure and nip width a. Here, it is important to regulate the contact pressure (the nip width); if the contact pressure is large, that is, if the nip width a is large, the cleaning roller 22 will force the image carrier l
*As a result, the surface of the image carrier 1 is damaged and the quality of the image is degraded. In addition, when the contact pressure is small, that is, when the nip width a is small, the image carrier 1 such as rosin, talc, or corona product
In some cases, it may not be possible to sufficiently remove substances that have strong adhesion to the surface.

To lightly press the developer onto the image carrier 1.

Some or all of the components of the developer may adhere to the surface of the image carrier 1 in the form of a film, resulting in a decrease in image quality. Nip width a
The appropriate value for cleaning roller 22. Although it varies depending on the material of the image carrier 1 and the relative speed of the cleaning roller 22 and the carrier 1, an organic optical semiconductor may be used as the image carrier 1.
When sponge-like silicone rubber is used as the cleaning roller 22, the peripheral speed of the image carrier l is 100 mm/s, and the peripheral speed of the cleaning roller is 140 mm/s, the nip width a is 0.2 as confirmed by experiment. ~4 m
m was preferable (1 to 2 mm was particularly preferable)
.

Using a cleaning device configured as described above, we conducted a continuous paper-feeding experiment using transfer paper with a lot of precipitates such as rosin and talc in a high-temperature, high-humidity environment. Disturbance of the latent image, damage to the surface of the image carrier, and filming on the surface of the image carrier due to a decrease in the surface resistance of the carrier were observed. Next, when a similar paper feeding experiment was carried out using a magnetic brush means such as that disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-104970, a deterioration in image quality due to disturbance of the latent image was observed after several dozen sheets.

Next, when we conducted a similar experiment using a non-magnetic elastic roller without a thin layer of toner as a cleaning roller and pressing it against the image carrier, we found that the surface of the image carrier was removed several times after passing dozens of sheets. The image quality deteriorated, and furthermore, the image quality deteriorated due to non-uniform frictional charging between the cleaning roller and the image carrier.

In the case of using magnetic toner in the above embodiment, a magnetic roller may be embedded inside the cleaning cola 22, and the rubbing action can be increased by the action of the magnetic field. Furthermore, if an abrasive such as CeO2 is mixed into the toner, the foreign matter removal effect will be further enhanced.

〔Effect of the invention〕

In the present invention, a non-magnetic elastic cleaning roller is disposed in pressure contact with the surface of the image carrier with a predetermined nip width on the upstream side of a cleaning blade that is disposed in pressure contact with the surface of the image carrier that is running, and the cleaning roller is attached to the surface of the cleaning roller. toner f
Since the two scrapers are arranged to form a calendar, paper dust, etc. that cannot be sufficiently removed by the cleaning blade can be removed.
The rosin, talc, or corona products that will precipitate can be sufficiently removed, and damage to the surface of the image carrier caused by the cleaning roller can be effectively prevented by the lubricating effect of the toner formed in the form of ItiFAL on the surface of the cleaning roller. Therefore, it is highly effective in obtaining stable images over a long period of time.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the main parts of an example of a cleaning device.
be. FIGS. 2 and 3 are sectional views of essential parts showing an embodiment of the cleaning device according to the present invention. In fig. 1, too...image carrier, 2.200...cleaning device, 21...cleaning plate, 22.
...Elastic cleaning roller, 23...Regulation roller, 2
4...Scraper, 202...Magnetic roller.

Claims (4)

[Claims] (1) In a cleaning device that removes residual toner on the surface of an image carrier using a cleaning means, an elastic cleaning roller that comes into pressure contact with the image carrier is disposed upstream of the cleaning means when viewed in the running direction of the image carrier, and the elastic cleaning A cleaning device having position regulating means at both ends of a roller for regulating the position of the roller and an image carrier. (2) The cleaning device according to claim (1), wherein the position regulating means is a regulating roller coaxial with the elastic cleaning roller. (3) The cleaning device according to claim (1), wherein the elastic cleaning roller is in contact with the image carrier. (4) The contact width between the cleaning roller and the image carrier is
The cleaning device according to claim 1, which has a diameter of 0.2 to 4 mm.