JPH0784479A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a cleaning blade having a small coefficient of friction with respect to the surface of an OPC photosensitive drum and stably functioning over a long period by making a coating layer into the layer of a small coefficient of friction formed on the surface where a releasing agent does not actually exist of the cleaning blade. CONSTITUTION:A plate-like blade is manufactured by cutting a centrifugally molded urethane sheet. After a plate metal is stuck to the blade, the surface of the blade is coated with a coating material by dipping through the use of a tank filled with the coating material. Then, the top end part of the blade is cut, and the releasing agent for coming into contact with a die is stuck to the A-surface of the blade. but the releasing agent, etc., are not stuck to the B-surface because it does not come into contact with the die. Then, the B- surface side of the blade is constituted so as to come into contact with a drum. Thus, the coating layer is hardly peeled compared with the case the side of the A-surface to which the releasing agent is stuck is abutted on the drum an excellent cleaning can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine and a printer.

[0002]

2. Description of the Related Art FIG. 4 is a schematic view for explaining a cleaning device as a cleaning means. A cleaning device 2 is provided in contact with a photosensitive drum 1 as an image carrier that rotates in the direction of arrow A.
The cleaning blade 3 is pressed against the surface of the photosensitive drum 1 in an inclined manner from the direction opposite to the rotation direction of the photosensitive drum 1. On the other hand, at the transfer portion, the residual toner 13 that does not contribute to the transfer and remains on the surface of the photosensitive drum 1 reaches the cleaning device 2 and is scraped off the surface of the photosensitive drum 1 by the cleaning blade 3 onto the squeegee sheet 15.

However, since the residual toner 13 on the drum has an electric charge, it adheres to the surface of the photosensitive drum by a strong electrostatic attraction force. In the case of the cleaner shown in FIG. 4, the cleaning blade uses this toner. Since the toner particles must be removed from the surface of the photosensitive drum by overcoming the electrostatic attraction force of the particles 13 on the surface of the drum, it must be pressed against the surface of the photosensitive drum with a large pressure.

On the other hand, since the cleaning blade 3 is required to have excellent chemical resistance, abrasion resistance, moldability and mechanical strength, urethane rubber having these various properties has been mainly used. However, since this urethane rubber cleaning blade has a very large coefficient of friction with the OPC photosensitive drum whose surface layer is made of a polymer resin such as polycarbonate, it has a large gap between the photosensitive drum and the cleaning blade. A frictional force is generated, the cleaning blade is turned over along the rotation direction of the photosensitive drum (blade is turned over), the photosensitive drum is not driven, and cleaning cannot be performed.

[0005]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus having a cleaning blade which has a small coefficient of friction with the surface of an OPC photosensitive drum and which functions stably over a long period of time.

[0006]

That is, the present invention has a running image carrier, and a cleaning blade for abutting the image carrier and removing toner remaining on the image carrier, and An image forming apparatus in which a cleaning blade has a coating layer, wherein the coating layer is a layer having a small friction coefficient formed on a surface of the cleaning blade substantially free of a release agent. Is.

For the coating layer having a small friction coefficient formed on the surface of the blade, a resin coating layer containing fine slippery particles is preferably employed. Such a coating material is prepared by uniformly dispersing the slippery particles in a resin-dissolved solution and coating the surface of the urethane cleaning blade without the release agent to form a low-friction blade.

By using particles having an irregular shape as the slippery particles, the binder resin for the coating layer is
Since the coating layer is formed in a fixed state by adding the mechanical fixing force due to the anchor effect, the slippery particles are more difficult to fall out of the coating layer, and the cleaning blade edge has a stable and low friction coefficient. Can be maintained.

As a method for manufacturing the cleaning blade, there are a method of injecting a urethane material into a mold to mold it into a blade shape, a method of forming a sheet-shaped urethane rubber by centrifugal molding, and then cutting it into a blade shape. The method using a mold allows the blade shape to be freely designed, but is costly in terms of cost. on the other hand,
In centrifugal molding, the degree of freedom of the blade shape is low, but mass production can significantly reduce the cost.

However, in any of the methods for manufacturing the cleaning blade, a mold is used when polymerizing the isocyanate and polyester, which are urethane materials, and at this time, in order to separate the mold from the urethane product,
Since the mold release agent is applied to the mold, the mold release agent adheres to the surface of the urethane rubber blade molded body. When such a blade surface is coated with a coating material, the coating layer is easily peeled off from the surface on which the release agent is present, which causes a problem of poor cleaning due to peeling of the coating layer during long-term use.

As a means for preventing this, there is a method in which the release agent adhering to the blade surface is treated with a chemical agent to remove it, or the blade surface is polished to scrape off the release agent. At present, it is difficult to completely remove the release agent, and thus it is difficult to completely prevent the peeling of the coating layer.

[0012]

【Example】

(Embodiment 1) FIG. 1 is a schematic diagram for explaining a first embodiment of the present invention.

A release agent is used between the blade and the die to improve the releasability of the blade from the die. For this reason, a part or all of the blade is attached with the release agent. . When a coating material is applied to the blade, the coating layer is easily peeled off at the part where the release agent is attached.Therefore, when the release agent is attached to the edge surface of the blade tip that contacts the photosensitive drum, The friction of the blade causes the coating layer to peel off, resulting in a problem such as defective cleaning.

In view of this, in this embodiment, by utilizing the fact that there is a portion on the surface of the urethane rubber that does not have a release agent during manufacturing in centrifugal molding, a coating material is applied to this portion and a blade that abuts against the drum is used. It is characterized in that it is configured to be an edge portion. FIG. 1 shows a blade manufacturing process in this embodiment. A plate-shaped blade is made by cutting a urethane sheet made by centrifugal molding. After the sheet metal is attached to the blade, the coating material is dip-coated on the surface of the blade using a tank filled with the coating material. Then, the blade tip is cut. Since the surface A of the blade contacts the mold, the mold release agent adheres thereto, while the surface B does not contact the mold, so the mold release agent and the like do not adhere thereto. Therefore, in the present embodiment, the blade surface B side is configured to contact the drum. As a result, the coating layer is less likely to peel off than in the case where the surface A side with the release agent is brought into contact with the drum, and good cleaning can be performed. When the coating layer on the blade was inspected by a peeling test, it was found that the peelability of the B side was about 2-3 times stronger than that of the A side. In addition, when the surface A side was in contact with the drum surface, peeling of the coating layer due to durability was observed, but the problem of coating layer peeling was solved by contacting the surface B side with the drum surface. did it.

The coating material used in the present invention is to reduce the frictional force between the blade and the drum and to effectively prevent the blade from turning over. For this purpose, the following coating material is used. Is effective. That is, by using a solvent in which the lubricating particles are uniformly dispersed, the frictional force between the drum and the blade is further reduced,
It is possible to more effectively prevent the blade from being turned over from the end. By using particles having an indefinite shape as the slippery particles, the coating layer is formed in a state in which the binder resin of the coating layer is fixed by adding a mechanical fixing force due to the anchor effect, so that the slippery particles are coated. It becomes more difficult to separate from the layer, and the edge of the cleaning blade can maintain the friction coefficient more stably and lower.

When the cleaning blade made of polyurethane rubber is brought into contact with the OPC photosensitive drum whose surface layer is made of a resin such as polycarbonate to perform cleaning, the cleaning blade contacts the photosensitive drum. As the coating layer to be formed on the contact portion, a coating layer composed of a resin layer obtained by dispersing fluorinated graphite powder in an organic solvent solution of a resin such as nylon and applying dipping coating on a cleaning blade, followed by drying, heating and curing. When formed, it was found that the blade turning can be prevented very effectively.

Examples of the fluorinated graphite that can be used in the present invention include (C ₂ F) _n type Cefbon DM.
(Manufactured by Central Glass Co., Ltd.), (CF) _n type Cefbon CMA, Cefbon CMF (manufactured by Central Glass Co., Ltd.), fluorocarbon # 2065, # 1030, # 1000 (manufactured by Asahi Glass Co., Ltd.), CF-100 (Nippon Carbon Co., Ltd.) Made) or (C
F) _n- type, fluorocarbon # 202 with different fluorination rate
No. 8, # 2010 (manufactured by Asahi Glass Co., Ltd.), and those obtained by treating the fluorinated graphite with a base such as amine to remove fluorine on the surface, but are not limited thereto. Further, the average particle diameter of the fluorinated graphite is preferably 20 μm or less, and particularly preferably in the range of 1 μm to 8 μm so as not to impair the cleaning of the toner.

(Embodiment 2) FIG. 2 is a schematic diagram for explaining this embodiment. A urethane sheet is molded by centrifugal molding as shown in Example 1. In this embodiment, at the stage of the urethane sheet, the coating material is sprayed on the surface of the sheet B and then cut to form a plate-shaped blade. At this time, the sheet B surface side is not in contact with the mold, and the release agent is not attached. Therefore, B
By coating the surface side, it is possible to create a blade in which separation of the coating layer and the urethane surface does not easily occur. Compared with the blade manufactured in Example 1, the number of manufacturing processes such as cutting is reduced, so that the cost can be reduced.

(Embodiment 3) In Embodiments 1 and 2,
The release agent should not be attached to the urethane surface that is not in contact with the mold, but the release agent or foreign matter may be attached due to some trouble during the manufacturing process, and the coating layer may peel off from it. There is. For example, the release agent becomes mist and scatters in the air, or the release agent is attached to the device in the sheet manufacturing process. It is conceivable that the agent or the like will adhere. Therefore, in this embodiment, after the urethane sheet is prepared, before coating the urethane surface with the coating material, at least a portion including the blade edge surface is polished to scrape off the release agent and the like that have adhered inadvertently. I'm dropping it. Further, by roughening the blade surface to some extent, it also has the effect of more firmly adhering the coating layer and the urethane surface, so it is possible to prevent further cleaning failure due to peeling of the coating layer, and realize good cleaning. It becomes possible.

(Embodiment 4) FIG. 3 is a schematic view for explaining the present embodiment, in which a blade is made by a mold.
In FIG. 3 (a), a urethane rubber is manufactured by injecting a liquid urethane material such as isocyanate and polyester into a mold molded into an appropriate blade shape and polymerizing in the mold. Next, in FIG. 3B, the created urethane rubber is cut into two pieces, each of which is subjected to a dipping treatment with a coating material in FIG.
Further, two cleaning blades are prepared by cutting the blade tip portion in FIG. 3 (d).

In the present embodiment, since the release agent is not attached to the cut surface X, by making this surface a contact surface with the drum, peeling of the coating layer can be prevented,
Good cleaning can be performed.

[0022]

As described above, according to the present invention,
An image forming apparatus having a running image carrier and a cleaning blade that is in contact with the image carrier and removes toner remaining on the image carrier, and the cleaning blade has a coating layer. Is a layer having a small coefficient of friction formed on the surface of the cleaning blade that is substantially free of the release agent, and a coating layer is provided on the blade surface with the release agent to contact the drum. The coating layer is less likely to peel off than when contacted, and good cleaning can be performed while effectively preventing cleaning failure due to peeling of the coating layer. Enabled equipment.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing Embodiment 4 of the present invention.

FIG. 4 is a schematic view showing a conventional cleaning device.

[Explanation of symbols]

 1 image carrier 2 cleaning device 3 cleaning blade 15 squishe sheet

Claims (2)

[Claims] 1. An image forming apparatus having a running image carrier and a cleaning blade which is in contact with the image carrier and removes toner remaining on the image carrier, and the cleaning blade has a coating layer. 2. The image forming apparatus as described in 1 above, wherein the coating layer is a layer having a small coefficient of friction formed on the surface of the cleaning blade substantially free of the release agent. 2. The image forming apparatus according to claim 1, wherein the coating layer is a resin film in which slippery particles are dispersed.