JPH05165386A - Powder coating method for cleaning blade - Google Patents

Abstract

PURPOSE:To form a powder coating layer on the surface of the rubber-like elastic material of a cleaning blade by applying an aq. emulsion of a resin having a specific softening point on the surface of the rubber-like elastic material and drying the emulsion at the temp. below the softening point of this resin. CONSTITUTION:The aq. emulsion of >=60 deg.C softening point is used in order to form the powder coating layer on the surface of the rubber-like elastic material 11 of the cleaning blade for cleaning the surface of a photosensitive body. Polyethylene, polypropylene, polyvinyl acetate, polyacrylates, polymethacrylates, etc., are used as such resin. The aq. emulsion of this resin applied on the blade rubber 11 of the cleaning blade forms the powder layer when the emulsion is applied on the surface of the blade rubber and is then dried at the temp. below the softening point of the resin. The powder applied on the cleaning blade in such a manner is the spherical powder having 0.1 to 10mum average grain sizes and drastically decreases the friction resistance of the cleaning blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating method for a cleaning blade for cleaning the surface of a photoconductor 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 photoconductor is developed with toner, and the toner image is transferred to a recording paper. Residual toner needs to be cleaned.
For cleaning the residual toner, a method is widely used in which an end surface edge of a blade made of a rubber-like elastic material typified by polyurethane is brought into sliding contact with the surface of the photoconductor to scrape off the toner.

However, when the cleaning blade is used, the frictional resistance between the blade and the surface of the photosensitive member is large, so that the cleaning blade may not start or the rubber of the blade may be wound around to damage the photosensitive member or the cleaning blade. .. This problem does not occur because the scraped toner acts as a lubricant for the blade when it starts up and the copying process completes one cycle.Therefore, the cleaning blade uses fine powder in advance to improve the sliding at the beginning of use. The method of attaching to the part is widely used. As the fine powder, a fluorine-containing polymer such as polyvinylidene fluoride or polytetrafluoroethylene is generally used. or,
A method of applying a coating of a fluorine-containing polymer to form a film with good sliding on the surface of the rubber blade may also be used.

However, the method of adhering powder such as fluorine-containing polymer to the blade rubber has the following drawbacks. The amount of powder adhered is not constant, and powder lumps easily form. The powder easily falls off, and if it is touched with a hand, a finger, etc., the powder comes off, and especially a lump of powder easily falls off. The powder is harmful to the image. The powder that has fallen off inside the copier deteriorates the image quality when mixed with the developing toner. Also, if it adheres to the charge line, black streaks will appear in that part and the image will be deteriorated. When powdering, the work environment becomes worse because the powder easily disperses 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 the frictional resistance remains on the blade surface even after the start of use, which deteriorates the toner cleaning performance.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to prevent the powder adhered from falling off, have a small effect on the image quality, have a good working environment, and have a small friction resistance at the start of use. It is to provide a body coating method.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for coating powder on the surface of a rubber-like elastic body of a cleaning blade for cleaning the surface of a photoconductor of an electrophotographic copying machine, in which an aqueous emulsion of a resin having a softening point of 60 ° C. or higher is used as a rubber. The present invention relates to a method for coating powder on a cleaning blade, which comprises coating a part or all of the surface of the elastic body and drying at a temperature lower than the softening point of the resin.

In the present invention, an aqueous emulsion of a resin having a softening point of 60 ° C. or higher is used. Suitable as such resin are polyethylene, polypropylene, polyolefins such as polyethylene / propylene copolymer, polyacrylic acid esters such as polybutyl acrylate,
Examples thereof include polymethacrylic acid esters such as polybutyl methacrylate, polystyrene, polyvinyl acetate, polyvinyl acetate / polyethylene copolymer, polystyrene / polyacrylic acid ester copolymer, and polyacrylonitrile, and a mixture thereof is also preferable. is there. The softening point of the above resin is 60 ° C or higher, preferably 80 to 160 ° C.

The resin emulsion of the present invention can be obtained, for example, by emulsion polymerization. The resin emulsion of the present invention is preferably diluted with water to a resin concentration of 10% or less before use.

The present invention is characterized in that the aqueous emulsion of the above resin is applied to a part or all of the surface of the rubber-like elastic body of the cleaning blade, and is dried at a temperature below the softening point of the resin. The emulsion coated by the method of the present invention forms a powder and does not form a film. When the softening point is low, the resin particles are fused and form a film when the coated emulsion dries, and the powder does not become a powder. Coating is dipping,
Brush coating, spraying or the like is used. When the coating surface is repelled, a small amount of a nonionic surfactant or the like may be added. Although addition of alcohols such as isopropyl alcohol is also effective, basically only water is preferable. Drying after coating may be performed at room temperature. In order to accelerate the drying
The heating may be performed at a temperature lower than the softening point, but in order to avoid fusion of the resin particles, it is preferable that the temperature is about 20 ° C. lower than the softening point or lower. The powder thus coated is spherical and has an average particle size of preferably 0.1 to 10 μm. If the average particle size is less than 0.1 μm, the effect as a lubricant becomes small, and if it exceeds 10 μm, the toner easily slips through, which hinders the cleaning performance of the cleaning blade.

[0011]

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

Example 1 As an emulsion, an example using Chemipearl W300 manufactured by Mitsui Petrochemical Co., Ltd. is shown. This resin is polyethylene with a melting point of about 120 ° C., and the powder after drying is spherical with an average particle size of 3 μm. The raw emulsion was diluted with water to a solid content concentration of 5%, and the cleaning blade was brushed onto the area shown in FIG. It was dried at room temperature for about 10 minutes.

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

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

To measure the frictional resistance at start-up, FIG.
When the rotating torque of the drum was measured by the device shown in Fig. 3, the resistance value was the same as that of the comparative sample, and the frictional resistance could be sufficiently reduced. Torque is 10kgfcm without powder.
The drum didn't rotate over. After rotating the drum once, removing the cleaning blade and observing the portion in contact with the drum, the powder in the portion was removed.

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

[0017]

[Table 1]

[0018]

According to the method of the present invention, the adhesive force of the powder is appropriate, the required amount can be applied uniformly, and the powder does not fall off. The friction resistance of can be reduced. And since the powder is spherical, it is highly effective as a lubricant. Furthermore, since the powder does not scatter in the air, the working environment is good. Compared to the film forming method, the applied powder does not form a film, so after the start of use, if the image forming process makes one cycle, it will be scraped off, so there is almost no effect on the cleaning performance of the cleaning blade thereafter. Absent.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram of a starting rotational torque measuring device.

[Explanation of symbols]

 1 Cleaning Blade 11 Blade Rubber 12 Holder 13 Powder Application Range 21 Drum 22 Torque Meter 23 Bearing

Claims (1)

[Claims] 1. A powder coating method for a rubber-like elastic body surface of a cleaning blade for cleaning a photosensitive body surface of an electrophotographic copying machine, wherein a water-based emulsion of a resin having a softening point of 60 ° C. or higher is used as a part of the rubber-like elastic body surface. Alternatively, a method for coating a powder of a cleaning blade, which comprises coating the whole or all and drying at a temperature lower than the softening point of the resin.