JPS6356976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cylindrical substrate for an electrophotographic photoreceptor using a paper tube.

The electrophotography referred to in the present invention relates to a copying method using a conventionally known electrophotographic process.

For example, using a photoreceptor in which an insulating layer, a photoconductive insulating layer, and a conductive layer are sequentially formed on a cylindrical substrate starting from the outermost layer, the surface of the insulating layer is first uniformly charged positively or negatively using an electrode or corona discharge. Then, the surface of the insulating layer to be charged is irradiated with the original image to be copied, and at the same time an alternating current corona discharge is applied to attenuate the charge on the irradiated area, thereby reducing the difference in surface potential that occurs according to the brightness pattern of the original image. After forming an electrostatic image on the surface of the insulating layer and visualizing the electrostatic image using a developer mainly composed of charged colored particles, the visible image is transferred to a transfer material such as paper using an internal or external electric field. is used to transfer the image, and then thermally fixes it to obtain an electrophotographic copy image.

If the electrophotographic photoreceptor described above is repeatedly used, its surface is likely to be damaged and deteriorated, and the quality of the copied images deteriorates due to fatigue of the photoconductive insulating layer over time. It is generally said that there are limits.

Therefore, in order to obtain high-quality copied images at all times, it is necessary to replace and update the electrophotographic photoreceptor at regular intervals, such as after copying 50,000 sheets.

Conventionally, a metal cylinder made of aluminum or the like has been generally used as the cylindrical substrate of an electrophotographic photoreceptor, and although this has the advantage that the substrate itself can be used as a conductor (the above-mentioned conductive layer), On the other hand, it is relatively expensive and, as mentioned above, has the disadvantage that it cannot be easily incinerated or otherwise disposed of after updating at regular intervals in order to obtain high quality copies.

Therefore, in an effort to obtain a cylindrical substrate that is inexpensive and can be easily disposed of by incineration, the inventor of the present invention, after various studies, came up with the idea of using a conventionally commonly used paper tube instead of a metal cylinder. The present invention was achieved by solving the problems in use as described below.

That is, the present invention provides a cylindrical substrate for an electrophotographic photoreceptor, which is obtained by polishing the surface of a paper tube by an appropriate method, covering the surface with a heat-shrinkable synthetic resin film, and heat-shrinking the film. It is in the manufacturing method.

There are some problems with using a paper tube as the substrate of an electrophotographic photoreceptor.

In other words, paper tubes are made by wrapping paper cut into tapes and pasting them with glue to form a tube, so there may be problems such as the inherent thickness of the paper, the seams of the paper, the binding fibers in the paper, etc. Foreign matter makes it difficult to obtain a smooth surface like that of a metal cylinder, and therefore unevenness appears on the insulating layer, photoconductive insulating layer, and conductive layer laminated thereon, making it difficult to obtain a high-quality copied image. Hard to get caught. In addition, since paper is a material that easily absorbs moisture, when applying a conductive layer, the coating liquid penetrates into the paper, making it difficult to obtain a normal coating surface. Expansion and contraction cause cracks in the paint layer.

Therefore, in the present invention, it is preferable to first use a method of spirally winding up a wide tape-like paper in order to obtain a paper tube with a surface as smooth as possible. At this time, using thick paper is advantageous in terms of efficiency in order to make a paper tube of the desired thickness, but deep depressions will occur where the paper meets the seams.
Thick paper is used at the beginning of winding the paper tube, and thin paper is used at the end of the winding, that is, at the portion that touches the surface of the paper tube. However, even with the method described above, it is not possible to obtain a paper tube with a completely smooth surface, so it is finished by polishing using an appropriate method, and then the surface of the paper tube is impregnated with resin and buffed in sequence. Then, the surface is covered with a heat-shrinkable film such as polyester film, and the film is heated to shrink. In this way, a cylindrical substrate is obtained in which the fuzz produced by polishing the paper tube is completely suppressed and the surface is smooth and completely impermeable to the coating liquid.

Next, to prepare an electrophotographic photoreceptor, fine carbon powder is dispersed in a vinyl-vinyl acetate binder and coated on the substrate to form a conductive layer. In the PVC-PVC binder, fine carbon powder is well dispersed, and the coating layer follows the expansion and contraction of the paper tube as a base material as it absorbs and desorbs moisture, without causing cracks.

Next, photoconductive fine powder such as CdS, CdSe, or ZnO is dispersed in a thermoplastic or thermosetting resin, or a thermosetting synthetic resin that is solvent-free and liquid at room temperature (e.g., epoxy resin, A photoconductive insulating layer is formed by dispersing it in a binder of polyester resin, and coating it on the conductive layer to form an electrophotographic photoreceptor.

Alternatively, one type of resin selected from polyethylene, polypropylene, polystyrene, silicone resin, etc. may be coated on the photoconductive insulating layer, or it may be covered with a tube of the above-mentioned synthetic resin film and then heat-shrinked. Then, a light-transmitting organic insulating layer is formed to form an electrophotographic photoreceptor.

According to the cylindrical substrate of the present invention, an electrophotographic photoreceptor formed using the same can achieve exactly the same effect as a conventional photoreceptor based on a metal cylinder, and in addition, it is entirely flammable. Since it is made of a durable material, it can be easily disposed of by incineration, and it is also extremely advantageous in terms of cost.

Note that in the cylindrical substrate of the present invention, the heat-shrinked film can be easily removed, so that if the film is removed, the conductive layer and photosensitive layer coated thereon can be removed together without having to discard the entire photoreceptor. Therefore, the paper tube before being coated with film can be reused.

Hereinafter, the present invention will be explained in detail using Examples.

Example Paper tube base paper cut into a tape shape with a width of 110 mm and a thickness of about 0.8 mm is pasted with glue and wound in a spiral shape so that the seam between the base papers has a gap of about 0.05 mm or less. The base paper on the surface of the outer layer is impregnated paper with a thickness of about 0.2 mm, which is pasted with glue and wrapped so that the seam between the base papers has an overlap of less than about 0.05 mm, and the outer diameter is 130 mm.
A paper tube with a wall thickness of 5 mm and a length of 280 mm was manufactured.

After roughly removing the overlapping portion of the base paper on the outer layer of the paper tube using an appropriate polishing machine, it was impregnated with an emulsion of Movinyl 730 (acrylic resin manufactured by Hoechst Synthesis) at a rate of 5 g/m ² in terms of solid content. , after air drying,
Buffing was performed to create a seamless paper tube.

When the roundness and cylindricity of the paper tube were measured,
In both cases, the accuracy was within 0.2 mm.

Next, the paper tube was covered with a cylindrical heat-shrinkable polyester film with a wall thickness of 20 μm and an outer diameter of 150 mm, which was heated to 90° C. in a hot air dryer and left for 30 minutes.
Shrunk.

Next, 10 parts by weight of carbon black and 8 parts by weight of vinyl chloride-maleic anhydride copolymer resin were placed in a ball mill and dispersed for 2 hours. A coating liquid was then applied to the surface and both end faces of the above-mentioned cylindrical substrate, and heated at 100°C for 30 minutes. It was dried for minutes to provide a 30μ thick conductive layer.

80 parts by weight of CdS and epoxy resin on the top surface of the conductive layer.
18 parts by weight of the epoxy hardener and 1.8 parts by weight of the epoxy curing agent amine were kneaded and coated to form a 45 μm thick photoconductive insulating layer, which was then covered with a 20 μm thick polyester tube and heated at 95°C for 15 minutes. An electrophotographic photoreceptor using this as an insulating layer was fabricated by shrink-wrapping it.

The electrophotographic photoreceptor obtained in the above manner exhibited exactly the same performance as a conventional electrophotographic photoreceptor using a metal cylinder such as aluminum.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor characterized in that the surface of a paper tube is polished, impregnated with resin, further buffed, the surface is covered with a heat-shrinkable synthetic resin film, and the film is heated to shrink the film. A method for manufacturing a cylindrical substrate for use.