JPH08314343A - Cleaning blade for electrophotographic device - Google Patents

Abstract

PURPOSE: To obtain a cleaning blade for an electrophotographic device which lessens the damage of a photoreceptor and has excellent durability by coating at least the part of a blade member which part comes into contact with the photoreceptor with polysilazane. CONSTITUTION: The blade member of the cleaning blade for the electrophotographic device constituting of the blade member, supporting member and adhesive layer is coated with the polysilazane at least on the part which comes into contact with a photoreceptor. At least the part of the blade member which part comes into contact with the photoreceptor is coated with a thin film (a thickness of submicron to several microns) constituting of the polysilazane or the sintered compact thereof and, therefore, the friction coefft with the photoreceptor is lowered without impairing the dimensional accuracy of the contact part with the photoreceptor. The polysilazane has the excellent adhesion property to polyurethane, etc., forming the blade member and, therefore, the peeling of the coating does not arise and the cleaning blade having the excellent durability is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning blade for an electrophotographic apparatus which comprises a blade member having a low friction coefficient.

[0002]

2. Description of the Related Art An electrophotographic apparatus has a photoconductor provided with a photoconductive layer on its surface. During operation, the outer peripheral surface of the photoconductor is uniformly charged, and then the object to be copied is covered. An electrostatic latent image is formed by exposing the outer peripheral surface through a copy image, toner is attached to the electrostatic latent image to form a toner image, and the toner image is transferred to paper or the like and fixed. Is.

In this process, a part of the toner remains on the outer periphery of the photoconductor after the transfer, and it is necessary to remove this residual toner. Such toner removal is performed by a cleaning blade. The cleaning blade is usually formed of a support member made of a metal plate, a blade member made of an elastic body, and an adhesive layer for attaching the blade member to the support member.

[0004]

The above blade member is
It is generally manufactured from urethane elastomer, but urethane elastomer has a large friction coefficient with the photoreceptor, and especially when the cleaning blade is attached to the photoreceptor for the first time, images with low toner consumption are continuously transferred. When a large number of copies are made, there is a problem that the blade edge portion is turned over due to a large frictional force and cleaning becomes impossible.

In order to avoid such a problem, it has been practiced to coat the blade edge portion with a fine powder of fluorine-based resin such as polyvinylidene fluoride and polytetrafluoroethylene to act as a lubricant. However, it is not easy to uniformly apply the fine powder in the longitudinal direction of the blade, and if there are variations in the application, there are drawbacks such as the above-mentioned inability to clean.

Further, while the cleaning is repeated, the fine powder is consumed, and instead of this, the toner acts as a lubricant, but the reduction of the lubricating effect is unavoidable and the mechanical strength is relatively low. When an organic semiconductor is used as a photoconductor, there are problems such as damage to the photoconductor and shortening of life.

In order for the cleaning blade to continue to exhibit stable performance for a long period of time, it is necessary that the edge of the blade member be in contact with the surface of the photosensitive member at all times with an appropriate pressure. Not only the smoothness of the cleaning blade tip edge is good, but also the blade member is mounted on the support member with high accuracy without misalignment, and the misalignment due to peeling, lifting from the support member, etc. Must be firmly fixed to prevent

In order to improve the above-mentioned problem of inability to clean, attempts have been made to include a lubricant in the material of the blade member, but the surface of the blade member containing such a lubricant is Since it is hydrophobized, problems such as difficulty in adhering to the support member occur.

In view of the above, it is an object of the present invention to provide a cleaning blade for an electrophotographic apparatus, which is less likely to damage the photoreceptor and has excellent durability.

[0010]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a cleaning blade for an electrophotographic apparatus comprising a blade member, a supporting member, and an adhesive layer, at least a portion of the blade member that is in contact with the photoreceptor. It is supposed to be covered with polysilazane.

The blade member used in the present invention is not particularly limited as long as it has a hardness of 40 to 95 (JIS-A), and for example, a thermoplastic elastomer, a thermosetting elastomer or the like can be used. Of these, thermosetting urethane elastomers are preferable.

Examples of the above-mentioned thermosetting urethane elastomer include those which are composed of an isocyanate compound, a high molecular weight polyol, and a crosslinking agent and which have undergone a thermosetting reaction.

Examples of the above-mentioned isocyanate compound include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI) and tolidine diisocyanate (TDI).
ODI) and the like.

Examples of the high molecular weight polyol include polyester polyol, polycarbonate polyol, polyether polyol, polycarbonate ether polyol and the like. Examples of the cross-linking agent include polyhydric alcohols such as butanediol, ethylene glycol, trimethylolpropane, and glycerin.

The blade member used in the present invention is a member in which at least a portion in contact with the photosensitive member is coated with polysilazane. The polysilazane is not particularly limited as long as it is a polymer having a silazane bond (-Si-N-) as a main chain, and examples thereof include Tonen polysilazane (manufactured by Tonensha) and Fricoat (manufactured by DEXTER). .

The method for coating the blade member with the polysilazane is, for example, a method of dissolving polysilazane in an organic solvent and immersing the blade member in this solution, or a method of spray-coating this solution on the blade member and then evaporating the solvent. Etc. can be mentioned. In the present invention, the polysilazane is preferably coated and then sintered. As a method of the above-mentioned sintering, after coating with polysilazane, 5
The heat treatment may be performed at 0 to 150 ° C.

The supporting member used in the present invention is not particularly limited as long as it is a commonly used member, and for example,
Examples include those manufactured from rigid metals, elastic metals, plastics, ceramics, etc. Among them, untreated steel sheets because they do not change over time and have corrosion resistance; zinc phosphate treatment, chromate treatment It is preferable to use a steel plate that has been subjected to a surface treatment such as;

The method for adhering the cleaning blade for an electrophotographic apparatus of the present invention may be a commonly used method. For example, a commonly used adhesive may be applied to the above supporting member, and the blade member may be bonded onto it. There are methods such as a method of heating and pressurizing, a method of integrally molding a supporting member coated with an adhesive by die molding and a blade member, and the like.

[0019]

In the cleaning blade for an electrophotographic apparatus of the present invention, at least a portion of the blade member that comes into contact with the photosensitive member is covered with a thin film (submicron to several microns thick) made of polysilazane or a sintered product thereof. Therefore, the friction coefficient with the photoconductor can be lowered without impairing the dimensional accuracy of the contact portion with the photoconductor.

Further, since polysilazane is also excellent in adhesion to polyurethane or the like which forms the blade member, the coating does not peel off and the durability is also excellent. In particular, when the polysilazane is applied and then sintered, the thin film becomes hard and strong, and the adhesion to the blade member is also increased, so that the friction and durability are further improved.

[0021]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 Ethylene adipate ester polyol (molecular weight 200
0) and 4,4′-diphenylmethane diisocyanate, 100 parts by weight of a urethane prepolymer (isocyanate content = 6.3%) and 1,4-butanediol / trimethylolpropane (molar ratio = 60/40).
A urethane composition consisting of 6.5 parts by weight of the above mixture was prepared, poured into a centrifugal molding machine (drum temperature 140 ° C., inner mold 720 mm, rotation speed 600 rpm), heated for 60 minutes, and taken out from the drum 110 ° C. A urethane elastomer sheet was prepared by further heating for 24 hours. By cutting this sheet into a predetermined size,
It was used as a blade member.

On the other hand, a supporting metal fitting manufactured using a phosphate-treated steel plate (Nippon Steel Co., Ltd. Bonde steel plate) was washed with methylene chloride, and a hot melt adhesive ( Henkel Hakusui, Macromelt 6
No. 238) was used to heat and melt it at 195 ° C., and the applicator was used to apply a thickness of 100 μm to a support fitting. A cleaning blade was produced by heating and pressurizing the support fitting and the blade member with a hot press to bond them. The tip of this cleaning blade was dipped in a polysilazane solution (Fricoat, manufactured by DEXTER) and dried at room temperature.

Example 2 Example 2 was repeated except that the tip of the cleaning blade was immersed in the polysilazane solution and then heat-treated at 110 ° C. for 1 hour.

Comparative Example 1 The procedure of Example 1 was repeated except that the tip of the cleaning blade was not immersed in the polysilazane solution.

Evaluation The obtained cleaning blades of Examples 1 and 2 and Comparative Example 1 were set in a Haydon surface property measuring machine, and the friction coefficient with an acrylic plate was measured. Further, the obtained cleaning blade was mounted on a commercially available dry plain paper electrophotographic copying machine, and the surface condition and blade edge portion of the photosensitive member after continuous copying of 35,000 sheets were observed, and the friction coefficient was also measured. The results are shown in Table 1.

[0027]

[Table 1]

[0028]

EFFECT OF THE INVENTION The cleaning blade for electrophotographic apparatus of the present invention, which has the above-mentioned constitution, has a low coefficient of friction, less damage to the photoconductor, and less abrasion of the blade edge portion, resulting in durability. Are better.

Claims (2)

[Claims] 1. A cleaning blade for an electrophotographic apparatus, comprising a blade member, a supporting member, and an adhesive layer, wherein the blade member is coated with polysilazane at least at a portion in contact with a photoreceptor. Cleaning blade for electrophotographic devices. 2. The cleaning blade for an electrophotographic apparatus according to claim 1, wherein the polysilazane is sintered.