JPH0143722Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cleaning blade in a wet electrophotographic apparatus.

2. Description of the Related Art Wet-type electrophotographic apparatuses, which form an electrostatic latent image or a magnetic latent image on a latent image carrier and wet-develop the formed electrostatic latent image, are well known as copying apparatuses.

The electrostatic latent image formed on the latent image carrier is wet-developed using a developer, but some of the toner that makes up the visible image remains on the latent image carrier. must be removed from the latent image carrier.

Regarding the removal of residual toner, the method of using a cleaning blade is conventionally well known.
Regarding the use of this cleaning blade,
The following problems arose.

FIG. 1 shows a typical latent image carrier cleaning method using a cleaning blade (hereinafter simply referred to as a blade), and only the parts necessary for explanation are schematically shown.

The latent image carrier 1 is formed into a drum shape and rotates in the direction of the arrow.

Toner remaining on the latent image carrier 1 is removed from the latent image carrier 1 by a cleaning roll 2 and a blade 3. That is, a cleaning liquid is supplied between the cleaning roll 2 and the blade 3, and a portion of this cleaning liquid impregnates the cleaning roll 2. The cleaning roll 2 containing the impregnated cleaning liquid rotates in the direction of the arrow and squeezes out the cleaning liquid.
The peripheral surface of the latent image carrier is rubbed to release some of the residual toner from the peripheral surface and to make the remaining toner easier to release from the peripheral surface. Then, the toner that is easily released is stripped off from the peripheral surface of the latent image carrier by the edge of the blade 3 that comes into pressure contact with the peripheral surface of the latent image carrier together with the cleaning liquid containing the already released toner. The toner thus removed from the peripheral surface of the latent image carrier is flushed away from the cleaning section by the cleaning liquid supplied to the cleaning section. However, in reality, the removed toner T tends to accumulate on the contact portion between the edge of the blade 2 and the peripheral surface of the latent image carrier, as shown in FIG.
The toner thus deposited gradually becomes a gel as the dispersion medium gradually evaporates while the electrophotographic process is not performed, and then solidifies over time.

Therefore, if the operation of the electrophotographic apparatus is stopped for a long time while the blade 3 and the latent image carrier 1 are kept in contact with each other, the blade 3 and the latent image carrier 1 will be exposed to toner T.
There is a problem in that the latent image carrier portion of the fixed portion is damaged during a new electrophotographic process.

The problem of adhesion between the blade 3 and the latent image carrier 1 is as follows.
When the device stops operating, the blade 3 and the latent image carrier 1
This can be solved by breaking contact with the blade 3 (see Figure 3), but even in this case, when the operation of the device is stopped for a long time, the toner T attached to the blade 3 may be in a gel state. and further solidifies.

When the toner solidifies on the blade 3 as shown in FIG. 3, when a new electrophotographic process is performed, the peripheral surface of the latent image carrier 1 is is rubbed by the solidified toner, damaging the peripheral surface of the latent image carrier.

When the latent image carrier is photoconductive, this damage is easily caused and is therefore a serious problem.

On the other hand, even if it does not solidify, toner that has become a gel adheres to and moves around the peripheral surface of the latent image carrier during a new electrophotographic process, causing abnormal images such as so-called black streaks and white spots. Become.

The cleaning blade is also used to clean the squeeze roller that removes excess developer from the surface of the latent image carrier after development, and if the visible image is transferred using the transfer roller, the cleaning blade is also used to clean the transfer roller. A cleaning blade is also used. Even in such a case, problems arise due to gelation or solidification of the removed toner, which may result in image abnormalities, malfunctions, and damage to the equipment.

Furthermore, the developing roller in the developing method in which the developer is attached to the peripheral surface of the developing roller and pumped up and supplied to the latent image, or in the direct recording method,
Squeezing rollers, cleaning rollers, blotter rollers, drying rollers, and the like are also members that come into contact with the developer, and when a cleaning blade is used to clean these members, similar problems occur. The various rollers mentioned above, such as the squeeze roller and cleaning roller, are
It may also be a belt with the same function.

An object of the present invention is to provide a cleaning blade that can effectively solve these problems. Here, the cleaning blade is a general term for a member that performs a cleaning action by coming into pressure contact with the surface of an object to be cleaned, such as a latent image carrier.

The present invention will be described below with reference to the illustrated embodiments.

FIG. 4 shows one embodiment of the present invention.

That is, the blade 30 has a blade main body 31
A coating layer 32 of an oil repellent agent is formed on the surface. In other words, this coating layer 32 is a feature of the present invention.

This blade 30 can be used not only as shown in FIG. 1, but also in any conventionally known blade cleaning method. Further, the blade body itself may be any conventionally known one. Of course, it can be easily applied to cleaning not only latent image carriers but also the various rollers and belts mentioned above, such as squeeze rollers and transfer rollers.

That is, when implementing the present invention, there is no need to newly construct a special cleaning blade, and a conventionally used cleaning blade can be used as is. Therefore, the present invention can be applied to new devices as well as very easily to existing devices.

The oil repellent coating layer 32 repels the dispersion medium in the developer and cleaning solution, so that its effect substantially completely prevents the removed toner from adhering to the blade 30. Therefore, in a system in which the blade and the latent image carrier are brought into constant contact with each other, the problem of sticking between the blade and the latent image carrier can be effectively solved.

Furthermore, in a method in which the contact between the blade and the latent image carrier is released while the electrophotographic process is not being performed, even if a small amount of cleaning liquid containing toner adheres to the blade, the adhesion force is extremely weak. Due to the movement of the blade when the contact between the blade and the latent image carrier is released, such adhering liquid is sieved off the blade, so that the toner is completely prevented from gelling or solidifying on the blade. Prevented. Further, in the case of a blade for cleaning a squeeze roller or a transfer roller, the width direction of the blade itself can generally be made close to the vertical direction. The toner removed by the blade has a weak adhesion to the oil repellent coating layer, and is easily removed from the contact area between the object to be cleaned and the blade due to the inclination of the blade. Thus, the present invention effectively solves the conventional problems.

Examples of oil repellents include tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, tetrafluoroethylene-hexafluoropropyline copolymer,
Examples include IH-pentadecafluorooctyl methacrylate, perfluorinated lauric acid, vinyl chloride, perfluorinated alcohol, perfluoroalkyl ester polymers, and fluorine-containing hydroxy unsaturated esters.

Generally, blades are often made of polyurethane, but developer or cleaning solution (generally, the developer itself or a mother liquor of the developer is used)
Isopar H, which is commonly used as a dispersion medium for polyurethane, has a contact angle of 3° with polyurethane, so the developer or cleaning solution tends to wet the polyurethane blade, causing toner transfer to the blade. Adhesion occurs.

However, when such an oil repellent as described above is applied to the blade surface, the contact angle increases by more than 20 times, and the developer and cleaning liquid are easily repelled by the oil repellent coating layer.

As for the method of applying the oil repellent, a method suitable for each oil repellent may be adopted. For example, in the case of IH-pentadecafluorooctyl methacrylate, it is sufficient to simply dilute it with a volatile solvent and spray it. In this case, with the evaporation of the solvent,
A coating layer is formed.

In the experiment, a coating layer was formed on a polyurethane blade using the above method using IH-pentadecafluorooctyl methacrylate as an oil repellent, and a developer containing Isopar H as a dispersion medium was used as a cleaning solution to carry a latent image. After cleaning the body, it was confirmed that the previous problems were completely resolved.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining blade-type latent image carrier cleaning, FIGS. 2 and 3 are diagrams for explaining the problems to be solved by the present invention, and FIG. 4 is a diagram for explaining the problem to be solved by the present invention. It is a figure for explaining one example of. 30...Latent image carrier cleaning blade, 3
1... Blade body, 32... Oil repellent coating layer.

Claims (1)

[Claims for Utility Model Registration] 1. In a wet electrophotographic device that supplies a developer to a latent image formed on a latent image carrier to develop the image, a device that is pressed against the surface of a member that comes into contact with the developer, A cleaning blade for removing adhering developer, the cleaning blade having an oil repellent layer on its surface. 2. A cleaning blade for a wet-type electrophotographic apparatus according to claim 1 of the utility model registration claim, characterized in that the pressure contact with the surface of a member that comes into contact with a developer is released when the wet-type electrophotographic apparatus is not in operation. 3. The cleaning blade for a wet-type electrophotographic apparatus according to claim 1 or 2, wherein the member that comes into contact with a developer is a latent image carrier. 4. The cleaning blade for a wet-type electrophotographic apparatus according to claim 1 or 2, wherein the member that comes into contact with a developer is a transfer roller. 5. The cleaning blade for a wet electrophotographic apparatus according to claim 1 or 2 of the utility model registration claim, wherein the member that comes into contact with a developer is a squeeze roller. 6. The cleaning blade for a wet-type electrophotographic apparatus according to claim 1 or 2 of the utility model registration claim, wherein the member that comes into contact with a developer is a developing roller.