JP3119921B2 - Cleaning blade powder coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of coating a cleaning blade for cleaning the surface of a photoreceptor of an electrophotographic copying machine.

[0002]

2. Description of the Related Art In an electrophotographic copying machine, a latent image formed on the surface of a photoreceptor is developed with toner, and the toner image is transferred onto a recording paper. It is necessary to clean the remaining toner.
For cleaning the residual toner, a method of scraping off the toner by sliding an end surface edge of a blade made of a rubber-like elastic material represented by polyurethane on the surface of the photoreceptor is widely used.

However, when the cleaning blade is started to be used, the blade may not start due to a large frictional resistance between the blade and the surface of the photosensitive member, or the blade rubber may be wrapped, thereby damaging the photosensitive member and the cleaning blade. . Once started and the copying process goes through, this problem does not occur because the scraped toner acts as a lubricant for the blade, so the cleaning blade uses a fine powder beforehand to improve the slip at the beginning of use. The method of attaching to a part is widely used. As the fine powder, for example, fluorine-containing polymers such as polyvinylidene fluoride and polytetrafluoroethylene are generally used. or,
A method of applying a fluorine-containing polymer paint to form a slippery film on the rubber blade surface may be used.

However, the method of adhering powder such as fluorine-containing polymer to blade rubber has the following disadvantages. The amount of powder adhered is not constant, and powder clumps tend to stick. The powder easily falls off, and the powder is removed when touched with a hand, a finger, or the like, and a lump of powder particularly easily falls off. Powder is detrimental to image. The powder that has fallen inside the copier deteriorates the image quality when mixed with the developing toner. Also, if it adheres to the charge line, a black streak appears at that portion, deteriorating the image. The powdering operation deteriorates the working environment because the powder is easily scattered in the air.

Further, in the method of forming a film by coating with a fluorine-containing polymer, the film does not easily wear, so that it remains on the blade surface even after the start of use and reduces the frictional resistance, thereby deteriorating the toner cleaning performance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the powder adhering from falling off, reduce the influence on the image quality, improve the working environment, and reduce the frictional resistance of the cleaning blade at the start of use. An object of the present invention is to provide a body covering method.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method of coating a rubber-like elastic body surface of a cleaning blade for cleaning the surface of a photoreceptor of an electrophotographic copying machine.
Apply an aqueous dispersion of polyethylene resin to part or all of the surface of the rubber-like elastic body, dry at room temperature , and apply
Ethylene resin is used as a spherical powder having an average particle size of 0.1 to 10 μm.
The present invention relates to a powder coating method for a cleaning blade, which is formed in a state .

In the present invention, an aqueous dispersion of a resin having a softening point of 60 ° C. or higher is used. Suitable as such a resin is polyethylene emissions. The softening point of the above resin is 60
° C or higher, preferably 80 to 160 ° C.

The resin dispersion of the present invention is obtained by, for example, emulsion polymerization. The resin dispersion of the present invention is preferably diluted with water so that the resin concentration is 10% or less.

The present invention is characterized in that an aqueous dispersion of the above resin is applied to a part or all of the surface of a rubber-like elastic body of a cleaning blade and dried at normal temperature . The dispersion coated according to the method of the invention forms a powder and does not form a film. If the softening point is low, the resin particles are fused to form a film when the applied dispersion is dried, and do not become powder.
Dipping, brushing, spraying and the like are used for coating. If repelling occurs on the coated surface, a small amount of a nonionic surfactant may be added. The addition of alcohols such as isopropyl alcohol is also effective, but basically only water is preferred. Drying after coating may be performed at room temperature. To speed up drying, heating may be performed at a temperature lower than the softening point,
In order to avoid fusion of the resin particles, the temperature is preferably about 20 ° C. lower than the softening point. The powder coated in this way is spherical and has an average particle size of preferably 0.1 to 10 μm. When the average particle size is less than 0.1 μm, the effect as a lubricant is reduced, and when the average particle size is more than 10 μm, the toner tends to slip through, which hinders the cleaning performance of the cleaning blade.

[0011]

The present invention will be described below with reference to examples.

Example 1 An example is shown in which Chemipearl W300 manufactured by Mitsui Petrochemical Industry is used as a dispersion . This resin has a softening point of 132 ° C and a melting point of about 12.
It is polyethylene at 0 ° C, and the powder after drying has an average particle size of 3
μm spherical. The raw material dispersion was diluted with water to a solid content concentration of 5%, and the cleaning blade was brush-painted in the range shown in FIG. Dry at room temperature for about 10 minutes.

As a comparative example, polyvinylidene fluoride powder (Kynor 461, Pen Ort Co., average particle size 5 μm) was powdered in the same range.

The cleaning blade used was a polyurethane rubber having a rubber hardness of 70, which was cut to a thickness of 2 mm, a total length of 320 mm, and a width of 17 mm, and bonded to a metal holder with a bonding width of 8 mm.

In order to measure the frictional resistance at the time of starting, FIG.
When the rotational torque of the drum was measured with the device shown in Table 2, the resistance was the same as that of the comparative sample, and the frictional resistance was sufficiently reduced. If no powder is applied, torque is 10kgfcm
After that, the drum did not rotate. After one rotation of the drum, the cleaning blade was removed and the portion in contact with the drum was observed.

The drum is an OPC photosensitive drum having a diameter of 85 mm and a total length of 340 mm, and can be freely rotated. A torque meter is attached to one end of the rotating shaft of the drum. By rotating the torque meter at about 60 rpm by hand, the drum rotates and the torque can be measured. Cleaning blade, contact pressure 15g
/ Cm so that the holder part was fixed. Table 1 shows the results
Shown in

[0017]

[Table 1]

[0018]

According to the method of the present invention, the powder adhesion is moderate, the required amount can be applied uniformly, and the powder does not fall off during storage or transportation, so that the inside of the copying machine can be contaminated. Therefore, the friction resistance at the start of use can be reduced. And since the powder is spherical, it is highly effective as a lubricant. Further, since the powder does not fly into the air, the working environment is good. Compared with the film forming method, the applied powder does not form a film, so if the image forming process goes through once after use, it will be rubbed and removed, and the effect on the cleaning performance of the cleaning blade after that will hardly be affected. Absent.

[Brief description of the drawings]

FIG. 1 is an example of a cleaning blade used in the present invention.

FIG. 2 is a schematic diagram of an apparatus for measuring a starting rotation torque.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cleaning blade 11 Blade rubber 12 Holder 13 Powder application range 21 Drum 22 Torque meter 23 Bearing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-158888 (JP, A) JP-A-61-3187 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/10 B05D 7/24 301

Claims (1)

(57) [Claims] In a method of coating a rubber-like elastic body surface of a cleaning blade for cleaning a photosensitive body surface of an electrophotographic copying machine, an aqueous solution of a polyethylene resin having a softening point of 60 ° C. or higher is used.
The dispersion was applied to a part or the whole of the rubber-like elastic body surface, normal
Dry at room temperature and apply polyethylene resin to the elastic body surface
A powder coating method for a cleaning blade, wherein the powder is formed in a state of spherical powder of 0.1 to 10 μm .