JPH0436783A - Image flowing preventing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for preventing image deletion in an electrophotographic copying method.

[Prior Art] Conventionally, electrophotographic photoreceptors have been prepared by providing a photoconductive layer mainly made of selenium or a selenium alloy on a conductive support, or by using an inorganic photoconductive material such as zinc oxide or cadmium sulfide as a binder. Generally known are those using an organic photoconductive material such as poly-N-vinylcarbazole and trinitrofluorenone or an azo pigment, and those using amorphous silicon.

The demand for the reliability of these photoreceptors to maintain high image quality over a long period of time is increasing year by year. However, when the photoconductive layer is exposed, damage caused by corona discharge during the charging process and physical or chemical damage caused by contact with other members during the copying process shorten the life of the photoreceptor.

As a method to overcome these drawbacks, a technique has been proposed in which a highly hard protective layer containing carbon or carbon as a main component is provided on the surface of the photoreceptor.

For example, one in which a protective layer made of amorphous carbon or hard carbon is provided on the photosensitive layer (JP-A-6O-249155), one in which a diamond-like carbon protective layer is provided on the outermost surface (JP-A-6L-255152), photosensitive layer. A high-hardness insulating layer containing carbon as a main component is formed on the layer (Japanese Patent Laid-Open No. 81-284
855) Or nitrogen atoms, oxygen atoms,
Those provided with a protective layer made of a plasma organic polymer film containing at least atoms such as halogen atoms and alkali metal atoms (
JP-A-88-97981~4), protection consisting of an amorphous hydrocarbon film produced by glow discharge containing at least chalcogen atoms, group II atoms, group II atoms, group V atoms, etc., on an organic photosensitive layer. Layered (Japanese Unexamined Patent Publication No. 68-220
166-9), etc.

Photoreceptors with these protective layers have increased mechanical strength and improved durability. However, it has been found that when used for a long period of time, it has the disadvantage that image deletion occurs in environments with high humidity or rapid changes in humidity.

This is because discharge products (nitrate ions, ammonium ions, etc.) generated by corona discharge are adsorbed on the surface of the protective layer.
It is thought that this occurs because when this discharge product absorbs moisture from the atmosphere, the electrical resistance in the direction of the surface of the protective layer decreases, making it impossible to maintain the electrostatic latent image.

[Problems to be Solved by the Invention] In order to solve the problems of the prior art, the present invention seeks to provide a method for preventing image deletion in a copying method using a photoreceptor having a surface protective layer with excellent mechanical strength. It is something to do.

[Means for Solving the Problems] The structure of the present invention for solving the above problems is as follows: (1) An electronic device in which a photosensitive layer and a surface protection layer made of carbon or carbon as a main component are successively laminated on a conductive support. An electrostatic latent image forming means, a developing means for developing the electrostatic latent image, a means for transferring the developed image, and a means for cleaning toner remaining on the surface of the photoreceptor after transfer are arranged around the photographic photoreceptor. A method of forming an image by an image forming apparatus, comprising means for contacting and removing discharge products adhering to the surface of the surface protective layer with a brush-like member; The electrical specific resistance of the member is 10 to 106Ω
A method for preventing image deletion characterized by e1m.

(3) The tensile strength of the brush-like member is 1.0 to 3.0 g/d
This is a method for preventing image deletion, characterized in that yn.

The present invention will be explained in more detail below.

The electrophotographic photoreceptor used in the present invention has a structure in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, and the surface protective layer has carbon or carbon as a main component. It preferably has a C-C bond similar to a diamond with an SP3 orbital, a Vickers hardness of 100 to 8000 kg/cs, and a specific resistance (specific resistance) of 1 x 107 to 1 x 10 Ωel. and has an optical energy band width (referred to as Eg) of 1 OeV or more. It is formed of a thin film that is transparent in the infrared or visible region. The thickness of the protective layer is 100 ~ lO
μm, preferably 1000 to 2 μm.

Such films are generally produced by sputtering, plasma CV
D. Formed by glow discharge decomposition method, photo-CVD method, etc.

The photoconductive layer used in the present invention is Se.

5e-Te, Se alloys such as Ag3 Se3, ZnO1C
Used are particles of a II-Vl group compound such as dSSCdSe dispersed in a resin, an organic photoconductive material such as polyvinylcarbazonyl, or a-3i.

There are no particular restrictions on the structure of the photoconductive layer, and it may be a single layer or a stack of a charge generation layer and a charge transport layer.

Further, an adhesive layer for increasing adhesion and an electrical barrier layer for preventing charge injection may be provided between the protective layer and the photoconductive layer.

As the conductive support, a conductor or an insulator treated for conductivity is used. For example, AI.

AI, Ag on insulating substrates such as metals or alloys such as Ni, Fes Cu, and Au, polyester, polycarbonate, polyimide, and glass.

Examples include those formed with a thin film of a metal such as Au or a conductive material such as In2O3, 5n02, or paper treated with conductivity.

Further, there are no particular restrictions on the shape of the conductive support, and plate-like, drum-like, or belt-like ones may be used as required.

In the method for preventing image blurring of the present invention, discharge products adhering to the surface protective layer are removed by contacting the surface protective layer with a superabsorbent resin.

According to the present invention, it is possible to automatically remove discharge products adhering to the surface of the protective layer during each copying process, and even if the number of copies increases, the surface of the protective layer can always be kept fresh. can be prevented.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Example] A polyamide resin subbing layer in which Tioz particles were dispersed was provided on an aluminum cylindrical support (outer diameter 40 mm, length 2.50 + ss), and a charge generation layer and a charge transfer layer were provided on top of the polyamide resin subbing layer. This is a photoreceptor in which a 20005 polystyrene intermediate layer is formed on the surface of the photoreceptor, and a protective layer is formed using a plasma CVD apparatus.

Protective layer film forming conditions NF3 flow rate: 50SCCM C2H4 flow rate: 150SCCM Reaction pressure
: 0.02torr first alternating type extrusion crab 4
00W 1B, 56MHz support bias voltage (RF specific output knee 400V The carbon or carbon-based protective layer obtained in this way has a specific resistance of 1 x 10-Ω・CWA% Vickers hardness 2 hardness 2800k/, optical The target energy band width was 1.8 eV, and the film thickness was 0.8 μι.

FIG. 1 is an example of a schematic configuration diagram of a copying machine that removes discharge products attached to the surface of a protective layer according to the present invention.

Around this photoreceptor drum l, there is a charger 2,
An exposure slit 8, a developing section 4, a transfer charger 5, a separation charger 6, a cleaning unit 7, and a discharge product removal unit 8 are arranged in this order. In the discharge product removal unit, a brush 9 contacts the photoreceptor while rotating to remove discharge products. The direction of rotation may be forward or backward relative to the photoreceptor.

The materials used to construct the brush include fibers such as rayon, acetate, nylon, polyester, acrylic, polypropylene, polyethylene, polyurethane, cotton, and wool, and are subjected to various conductive treatments to control electrical resistance.

Conductive treatment methods include baking and carbonizing the above-mentioned fibers, coating with metal by plating or vacuum deposition, coating the surface with conductive fine particles, and blending or multicore composite spinning with conductive fine particle polymers. etc. can be exemplified.

The thickness of the fibers is preferably 5 to 15 ('denier/filament). Also, the density of the brush is 10,000 to 1
00,000 (pieces/1neh') The bristles length of the brush is 1~10■
■ is appropriate.

The brush can be constructed by directly fixing brush fibers onto a support, or by fixing a fabric of brush fibers onto a support by adhesive or other means.

Further, the brush may be placed at any position or timing in the copying process to bring the brush into contact with the photoreceptor surface as long as it does not disturb the toner image on the photoreceptor.

Further, the brush may be brought into contact with the photoreceptor continuously during the copying cycle, or may be brought into contact with the photoreceptor at appropriate times when necessary. Furthermore, when bringing the brush into contact with the photoreceptor surface, the linear velocity of the brush surface and the photoreceptor surface may be the same, or they may be rotated in the forward or reverse direction to improve contact efficiency. do not have.

Using this photoreceptor and changing the electrical resistance of the brush fibers during the copying process, we conducted a copying test of 30,000 copies at high temperature and high humidity (80°C, 90%), and the results shown in Figure 2 were obtained. .

Next, when the tensile strength of the brush fibers was changed and a copying test was conducted under the above conditions, the results shown in FIG. 3 were obtained.

As is clear from this result, the tensile strength of the fiber is 1.
The best results were obtained in the range of 0 to Leg/dyn.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the configuration of a copying machine, which is an example of an image forming apparatus used in the method of the present invention, and Fig. 2 shows the relationship between the electrical resistivity of brush fibers used in the method of the present invention and the rank of image deletion. The graph shown in FIG. 3 is also a graph showing the relationship between the tensile strength of brush fibers and the image blur rank. l... Photoreceptor having a protective layer, 2... Charger, 8... Exposure slit, 4...
Developing section, 5 Transfer charger, B Separation charger, 7 Toner cleaning unit, 8 Discharge product removal unit, 9 Brush.

Claims (3)

[Claims] (1) An electrostatic latent image forming means is placed around an electrophotographic photoreceptor in which a photosensitive layer and a surface protective layer consisting of carbon or carbon as a main component are successively laminated on a conductive support, and this electrostatic latent image is developed. In a method of forming an image using an image forming apparatus which is provided with a developing means for transferring the developed image, a means for transferring the developed image, and a means for cleaning the toner remaining on the surface of the photoreceptor after transfer, the discharge attached to the surface of the surface protective layer is A method for preventing image deletion, comprising means for contacting and removing a product with a brush-like member. (2) The electric specific resistance of the brush-like member is 10~10^6Ωc
The method for preventing image deletion according to claim 1, wherein m. (3) The tensile strength of the brush-like member is 1.0 to 3.0 g/d
The method for preventing image deletion according to claim 1 or 2, characterized in that yn.