JPH0582589B2 - - Google Patents

Description

Detailed Description of the Invention Scope of Industrial Application The present invention involves forming an electrostatic latent image on an image carrier, forming a transferable image on the surface of the image carrier using a developer, and transferring the image. The image is transferred onto the material surface, and the image is fixed on the transfer material and discharged outside the machine as a copy. After the image transfer, the image carrier surface is cleaned by cleaning means to remove the remaining image, and the image formation process is repeated. The present invention relates to a transfer-type image forming apparatus used in the image forming apparatus, and particularly relates to a cleaning apparatus using a roller as a cleaning means or its auxiliary means.

BACKGROUND TECHNOLOGY In a transfer type image forming apparatus as described above, the surface of an image carrier is cleaned by a cleaning means every image forming cycle to remove residual transfer images and other loose adhered contaminants, but image formation does not occur repeatedly. As they are used, they gradually become contaminated with stubborn deposits that cannot be removed by the cleaning means described above.

For example, the transfer residue is not only the untransferred toner but also the components of the paper during transfer, which are transferred to the image carrier and firmly adhered electrostatically. The paper powder that adheres in this way includes fibrous paper powder that can be seen with the naked eye, and paper components such as talc and clay that are invisible to the naked eye. Of these, fibrous paper dust gets caught in cleaning means such as blades and brushes, causing cleaning failures. In addition, paper components such as talc and clay, which cannot be seen with the naked eye, cannot be removed by conventional cleaning means (blades, brushes, webs, etc.) and gradually accumulate on the surface of the image carrier, causing contamination. Surfaces contaminated in this way are subject to electrical conductivity due to corona discharge or moisture absorption during various image forming processes, such as electrophotographic photoreceptors and electrostatic recording dielectrics. Properties such as characteristics may be partially or totally changed, resulting in a decrease in image forming ability. Then, for example, so-called image deletion, image missing (white spots), image density unevenness, etc. occur. Image flow occurs when an electrostatic latent image is formed in electrophotography, electrostatic recording, etc. When the charge on the charged part of the image carrier surface flows to the uncharged part due to the presence of attached contaminants, and when the latent image is developed, the ink flows. This is a phenomenon in which the developed image is developed even in the non-image areas. Image deletion, on the other hand, is a phenomenon in which an image is not formed on a contaminated surface of an image carrier, resulting in partial defects in the image.

Furthermore, paper contains a large amount of rosin, and as this adheres to the image carrier, the frictional resistance gradually increases. This will cause the cleaning blade to chatter and cause problems such as curling.

Except for the above fibrous paper powder, talc, clay,
An effective method for removing paper components such as rosin is to rub the image bearing member with a developer and entangle the developer with these contaminants, thereby simultaneously removing the developer and the contaminants. For this purpose, as shown in FIG. 1, there is a method in which an elastic roller 3 is pressed against the image carrier 1 and the image carrier 1 is rubbed with the developer 5 placed on the roller. This is because, as shown in Figure 2, the fibrous paper powder 7 is rubbed together with the developer on the roller between the roller 3 and the image carrier, and when it passes through the nip of the roller, the developer is removed as shown in 8. Intertwined with each other to form a dumpling-like shape. The paper powder thus formed into a ball is easily scraped off with a blade and collected in a waste toner receiver (not shown).

In addition, components of the paper that are invisible to the naked eye can be removed together with the toner by rubbing with the toner present. This is the same principle that, for example, can remove oil by sprinkling sand on an oil-stained object and rubbing it.

The above method is particularly suitable for amorphous silicon (a-
Effective for image carriers with hard surfaces such as Si).

In order to achieve these, a developer layer is created by separating a regulation plate 4 for regulating the amount of toner on the roller 3 from the roller for a certain period of time or by lightly pressing it against the roller, as shown in FIG. However, in such a method, if the regulating plate 4 is pressed too hard, the developer layer on the roller becomes thin and the effect is almost lost.

Furthermore, if the distance is too high, the developer layer becomes thick, and as shown in FIG. 4, a rolling phenomenon of the developer occurs between the image carrier surface 1 and the roller surface 3, and the rubbing effect is halved. Further, as shown in FIG. 5, developer leaks from between the roller 3 and the regulating plate 4, contaminating the interior of the machine, or falling onto the transfer material, seriously damaging the image. For this reason, it was very difficult to set the regulating plate 4, and the stability due to durability was also very low.

OBJECTS OF THE INVENTION The present invention has been proposed in view of the above-mentioned drawbacks, and it is easy to set the regulating plate 4, there is no toner leakage, and furthermore, the rubbing effect is large, and it is stable in durability, that is, it always produces stable and good images. It is possible to obtain.

The present invention to solve the above problems includes a roller with an insulating surface that is rubbed on an image carrier to remove residue on the surface of the image carrier, and a regulating member that regulates the residue attached to the roller. In a cleaning device with a cleaning device, the roller surface is charged in a polarity opposite to that of the toner due to the friction between the roller and the residue on the surface of the image carrier, so that the toner in the residue adheres to the roller surface as the roller rotates. The toner is charged to a polarity and as the roller rotates, the toner adhering to the roller surface is conveyed again to a rubbing area between the roller and the residue on the surface of the image carrier to remove the residue on the surface of the image carrier. Features.

Embodiment According to the present invention, the surface layer of the elastic roller is made insulating, and the roller is made of a material that triboelectrically charges the polarity of the developer during development due to friction with the transfer residue. By doing this, first of all, when the untransferred developer rushes into the elastic roller, the triboelectric charge (amount of charge due to frictional charging) of the developer increases due to the friction with the roller. The roller is charged with a polarity opposite to that of the developer. The developer then adheres firmly to the roller electrostatically.
At this time, as shown in Fig. 6, even if the developer scraping member (hereinafter referred to as scraper) 4' on the roller comes into strong contact with the roller, the roller and developer are strongly electrostatically attached. , several layers of developer remain. This state is most effective for rubbing the image carrier. Furthermore, developer leakage is completely eliminated.

In other words, the contact state of the scraper can be in a fairly wide range, whether it is weak or strong, making it possible to coat a stable thin layer of developer. Therefore, the rubbing effect on the image bearing member is stabilized, and the toner collection effect and scattering prevention effect are also improved.

At this time, the triboelectricity of the developer is 5μc/g or more, and the roller has the opposite polarity to this triboelectricity, so its absolute value is
It showed good performance at 1.5K~3KV.

For example, when a positively charging developer is used, silicone rubber, silicone rubber with Teflon dispersed therein, or a Teflon roller exhibits very good characteristics. When using a negative charging developer, use urethane rubber mixed with nylon resin, silicone rubber with amino-modified silicone oil added, or silicone rubber with amino-modified silica (SiO ₂ ).
It's better if it's mixed in. At this time, the developer remaining on the transfer is 3 to 5 μc/g, but on the roller it is 8 to 5 μc/g.
It was 10μe/g, and the roller was -2.5KV. The hardness of the roller is Asker C, about 25 to 40 degrees, and the nip when it comes into contact with the image carrier is 0.5 to 2.5.
mm was good. Further, at this time, the contact state of the scraper was such that the penetration amount was 0.05 to 0.6 mm, and a good scrape state was obtained.

The materials in the above embodiments are merely examples, and all other methods and configurations based on the idea of the present invention are included in the present invention.

Needless to say, in the above embodiments, the positively chargeable developer was described, but the same applies to the negatively chargeable developer.

Effects of the Invention As described above, stable sliding can be achieved by using a simple and inexpensive method in which the surface layer of the elastic roller is made of a material that is insulating and is charged to the opposite polarity to the polarity of the developer upon friction with the developer. It has a rubbing effect, prevents the developer from scattering, and provides a stable cleaning effect in terms of durability.

[Brief explanation of the drawing]

FIGS. 1 to 5 are cross-sectional views explaining the prior art;
FIG. 6 is a sectional view showing an embodiment of the present invention. 1 is an image carrier, 2 is a cleaning blade, 3
4 is an elastic roller, 4' is a scraper, and 5 is a developer remaining after transfer.

Claims (1)

[Claims] 1. A cleaning device comprising: a surface insulating roller that is rubbed on an image carrier to remove residues on the surface of the image carrier; and a regulating member that regulates residues attached to the roller. In the apparatus, the roller surface is charged with toner by rubbing between the roller and the residue on the surface of the image carrier so that the toner in the residue adheres to the roller surface as the roller rotates. The image carrier is charged with a polarity opposite to the polarity, and as the roller rotates, the toner adhering to the surface of the roller is conveyed again to a rubbing area between the roller and the residue on the surface of the image carrier. A cleaning device characterized in that it removes surface residue.