JPS6155673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image bearing member for holding an electrostatic or toner image.

Electrostatic or toner images are formed by various processes. Image holding members on which electrostatic images or toner images are formed include image holding members that have a photoconductive layer and those that do not have a photoconductive layer, which are called electrophotographic photoreceptors. An image-bearing member usually consists of a support and an image-bearing layer thereon.

Electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on the type of electrophotographic process to which they are applied. Typical electrophotographic photoreceptors include a photoreceptor in which a photoconductive layer is formed as an image-retaining layer on a support, and a photoreceptor in which a photoconductive layer is laminated as an image-retaining layer and an insulating layer thereon. is widely used. A photoreceptor composed of a support and a photoconductive layer is used for image formation by most common electrophotographic processes, ie, charging, image exposure and development, and optionally transfer. For photoreceptors with an insulating layer, the insulating layer may be used to protect the photoconductive layer, improve the mechanical strength of the photoreceptor, improve dark decay characteristics, or be applied to certain electrophotographic processes. It is established for the purpose of Representative examples of photoreceptors having such insulating layers or electrophotographic processes using photoreceptors having insulating layers include, for example, U.S. Patent No. 2,860,048, Japanese Patent Publication No. 16429/1980,
Special Publication No. 38-15446, Publication No. 3713-1971, Publication No. 23910-1972, Publication No. 24748-1974, Publication No. 24748-1974, Publication No. 19747-1974, Publication No. 4121-1974
It is stated in the issue bulletin etc.

A predetermined electrophotographic process is applied to the electrophotographic photoreceptor to form an electrostatic image, and this electrostatic image is developed and visualized.

A typical structure of an image holding member without a photoconductive layer is one having an insulating layer as an image holding layer,
Some typical uses of this image holding member will now be described.

(1) For example, Japanese Patent Publication No. 32-7115, Japanese Patent Publication No. 32-7115,
As described in Japanese Patent Publication No. 8204 and Japanese Patent Publication No. 43-1559, electrostatic images formed on electrophotographic photoreceptors without a photoconductive layer are used for the purpose of improving the repeatability of electrophotographic photoreceptors. The toner image is transferred to an image holding member and developed, and then the toner image is transferred to a recording medium. An image holding member used in this electrophotographic process.

(2) In addition, as another electrophotographic process in which an electrostatic image is formed on an image holding member without a photoconductive layer in correspondence with an electrostatic image formed on an electrophotographic photoreceptor, for example, Japanese Patent Publication No. 45-30320 Publication No., Tokukosho
As described in Japanese Patent Application Laid-open No. 48-5063 and Japanese Patent Application Laid-Open No. 51-341, an electrostatic image is formed on a screen-shaped electrophotographic photoreceptor having a large number of fine openings by a predetermined electrophotographic process. By applying corona charging to an image holding member without a photoconductive layer through this electrostatic image, the ion flow of the corona is modulated and the electrostatic image is transferred to an image holding member without a photoconductive layer. An example of this process is to form an image, develop it with toner, and transfer it to a recording medium to form a final image. An image holding member used in this electrophotographic process.

(3) In addition, according to other electrophotographic processes, a toner image formed on an electrophotographic photoreceptor or an image holding member without a photoconductive layer is not directly transferred to a recording medium, but instead has an additional photoconductive layer. Then, the toner image is transferred from this image holding member to a recording medium and fixed. An image holding member used in this electrophotographic process. This process is particularly useful for forming color images or for high speed copying. Recording media are usually highly flexible, such as paper or film, and for this reason, it is possible to transfer a three-color image onto a recording media while accurately aligning it, with almost no deformation. A more accurately aligned color image is formed by transferring a three-color image to an image holding member that can be formed from a suitable material and then transferring it to a recording medium at once. In addition, for speeding up copying,
It is advantageous that the toner image is transferred to the recording medium via the image bearing member. The image holding member is required to have physical properties and electrical properties depending on the electrophotographic process to which it is applied, and is also required to have mechanical durability. The image holding member is charged with corona, exposed to light,
Various processes such as transfer, development, and cleaning are involved, and the insulating layer of the image holding member must satisfy all the characteristics, but it is difficult to find an optimal one that has excellent durability for repeated use. .

Furthermore, some resins tend to attract toner particles or specific components contained in the toner, and image holding members using such resins cause background stains on images.

SUMMARY OF THE INVENTION The main object of the present invention is to provide an image holding member that has excellent electrical properties and mechanical durability, and has less toner adhesion.

The image holding member according to the present invention has a polyarylate resin layer as an insulating layer of an image holding member having an insulating layer on a photoconductive layer or as an image holding layer of an image holding member without a photoconductive layer. This is a characteristic feature. The polyarylate resin is a polyester of aromatic dicaribonic acid and bisphenol A, and its structure is shown in the following formula.

Products using polyarylate resin for the insulating layer have good electrical characteristics and are highly durable against deterioration.

In addition, it is less soluble in solvents, has good mechanical properties, and exhibits properties that cause very little staining by toner.

As a result, an image holding member that can provide high quality images for a long time is produced. An image bearing member usually consists of a support and an insulating layer formed thereon.

When the image holding member is an electrophotographic photoreceptor, it consists of a support, a photoconductive layer, and an insulating layer. The support is made of a material such as aluminum, copper, or stainless steel and is used in the form of a cylinder or sheet. The photoconductive layer is Se, Se-Te, Se-Te-As, ZnO, CdS,
It is formed by vapor deposition, sputtering, coating, etc. of photoconductive materials such as CdSe, PVK, and phthalocyanine alone or together with a binder. The thickness of the photoconductive layer varies depending on the material used, but is usually 5 to 50 μm.
That's about it. When the photoconductive layer is formed by coating, a resin layer that does not penetrate into the photoconductive layer may be provided to improve solvent resistance.

An insulating layer of polyarylate resin is applied onto this. Polyarylate resin is chlorobenzene,
It is dissolved in a solvent such as chloroform, methylene chloride, or tetrahydrofuran and applied at an appropriate viscosity. If the polyarylate resin layer alone causes high friction, it is also effective to use polytetrafluoroethylene (PTFE) powder dispersed in the polyarylate resin. An insulating layer with dispersed PTFE has lower friction and is suitable for cleaning processes with rubber blades. Use PTFE that is as finely powdered as possible, add dispersion aids such as fluorine-based and silicone-based as necessary, and process polyarylate resin using methods such as ball mill, homogenizer, roll mill, ultrasonic, colloid mill, etc. Dispersed in solution. The mixing ratio of PTFE is 2 to 50%, preferably 5 to 50%, based on the polyarylate resin.
It is 30%. Since the friction of polyarylate resin is not relatively high, it is not necessary to mix it in a large amount. If the amount is too large, the mechanical strength will decrease.

A polyarylate resin in which PTFE is dispersed as necessary is applied and, after a certain period of drying, becomes an insulating layer. The thickness of the insulating layer is 5 to 50μ, preferably 10 to 30μ
μ. When forming an insulating layer, another resin layer may be provided under the polyarylate resin.

Such resins include acrylic, polyurethane, epoxy, polyester, and acrylate photocurable resins.

The image holding member manufactured in this manner and having a polyarylate resin layer on its surface can stably form a high quality image due to its excellent properties.

Example 1 100 parts of CdS powder (parts by weight, the same applies hereinafter), 15 parts of diallyl phthalate resin (trade name: Daiso Tap, manufactured by Osaka Soda) as a binder, and 0.5 parts of benzoyl peroxide were dissolved in methyl ethyl ketone solvent and milled using a roll mill device. The mixture was mixed thoroughly to form a photoconductive paint. This was applied to an 80 x 300 mm Al cylinder by dipping, and cured at 110°C for 10 minutes to form a photoconductive layer with a thickness of 40 μm. Next, add 3 benzoyl peroxide on top of this.
A diallyl phthalate resin (same as above) solution containing % by weight was applied and cured at 110°C for 10 minutes to form a 10μ thick resin layer.

Next, urethane acrylate resin (trade name:
Sonne (manufactured by Kansai Paint Co., Ltd.) was applied and cured by irradiation with ultraviolet light to form a 10μ thick layer.

On the other hand, polyarylate resin (product name: U-100
Dissolve 10 parts of Unitika) in 30 parts of chlorobenzene, and add 2 parts of PTFE powder (trade name: Lublon L2, manufactured by Daikin Industries) and 0.2 parts of a surfactant (trade name: Chlorado FC431, manufactured by 3M). In addition,
Dispersion treatment was performed using a ball mill. Apply this liquid and
An insulating layer with a thickness of 4 μm was formed.

The photoreceptor thus obtained was subjected to primary +6KV corona charging, secondary AC corona charging, simultaneous image exposure,
Full-surface light irradiation, dry toner development, transfer to plain paper,
An electrophotographic copying machine was evaluated, which consisted of cleaning with a urethane rubber blade (2 mm thick, 30° angle, 10 gw/cm pressure). The images were of very good quality and the cleaning properties were also good. Further, even after a durability test of 50,000 sheets, there were almost no scratches on the surface of the photoreceptor, and there was no deterioration in cleaning performance.

Furthermore, in this example, the following photoreceptor was created.

A A photoconductor was prepared in the same manner as in Example 1, but
PTFE is not dispersed in the polyarylate layer on the surface.

B: The photoconductor of Example 1, but without applying polyarylate at the end, urethane acrylate resin was further applied to a thickness of 4 μm.

Photoreceptor A was in good condition initially, but after about 20,000 sheets of photoreceptor A, scratches on the surface began to increase and scratch marks appeared on the images.

This occurred because the friction was greater than with PTFE. Photoreceptor B had a sliding sound of the blade from the beginning, and the cleaning was sufficient.

Claims (1)

[Scope of Claims] 1. In an image holding member for holding an electrostatic image or a toner image, it can be used as an insulating layer of an image holding member having an insulating layer on a photoconductive layer, or as an insulating layer of an image holding member having no photoconductive layer. An image holding member comprising a polyarylate resin layer as an insulating layer serving as an image holding layer. 2. The image holding member according to claim 1, wherein polytetrafluoroethylene powder is dispersed and contained in the polyarylate resin layer.