JPS6245549B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic copying master paper having a photoreceptor used in an electronic copying machine. Hereinafter, the electrophotographic copying master paper having this photoreceptor will be abbreviated as an electrophotographic photoreceptor.

The electrophotographic method is a method in which optical information is subjected to electronic development within a solid to form a permanent image using a physical process.

Original image information is transmitted, reflected, or transmitted through a lens system by light, and this light image causes a photoconductive change in the physical properties of the photosensitive surface to form an electrostatic latent image. Various methods have already been proposed for forming this as a visible image and further as a permanent image. For example, in JP-A-49-120641, an electrophotographic photosensitive layer is provided on one side of a paper support, a conductive layer is provided on the opposite side, and an insoluble resin layer is further provided on the conductive layer. Electrophotographic paper is listed. This discloses an electrophotographic method in which a toner image is formed on an electrophotographic photosensitive layer to form a permanent image, and an electrophotographic paper carrying this image is used as an original for diazo copying. The water-insoluble resin on the back side is effective in preventing curling throughout the process, regardless of the humidity or temperature in the atmosphere.

The present invention relates to another electrophotographic method, and is an invention in which a specific electrophotographic photoreceptor is used in an electrophotographic method in which the steps of charging, exposure, development, transfer, and cleaning are repeated.

Generally, this type of electrophotographic photoreceptor is used by being attached to a photoreceptor conveying device of an electronic copying machine. For example, as shown in FIG.
An electrophotographic photoreceptor 3 is mounted on an endless belt 2 suspended by the endless belt 2 so that its photosensitive layer faces the outer surface, and is conveyed by the endless belt 2 in the direction of the arrow. That is, after the photosensitive layer is uniformly charged by the charger 4, the exposure mechanism 5
The electrostatic latent image thus formed is developed by a developing device 6 to form a toner image, and this toner image is transferred to a transfer paper (not shown) by a transfer pole 7. After that, a cleaning mechanism 8, the photoreceptor 3 is moved so that the residual toner is cleaned and the photoreceptor 3 returns to its original position. The toner image on the transfer paper is then fixed to become an electrophotographic image. Further, reference numeral 9 denotes a fixed master frame for keeping the photoreceptor 3 flat in the area where it is charged and exposed.

Conventionally, in the photoreceptor, a conductive layer made of aluminum or the like is provided on one surface of a sheet-like base material made of paper or plastic film, and a conductive layer made of aluminum or the like is provided on one side of the support. The structure is such that a photoconductive photosensitive layer is provided through an intermediate layer, so that the photoconductive layer itself can maintain sufficient flatness, can be mounted on a conveying device in an appropriate state, and can be moved in a predetermined manner. It has appropriate flexibility and strength against tension so that it can move smoothly on the road.

However, in the conventional photoreceptor, when it is repeatedly subjected to electrophotographic formation, the charger 4
The back surface opposite to the photosensitive layer is damaged due to electric discharge from the transfer pole 7, friction with the fixed master pedestal 9 due to movement, and friction with the developing brush of the developing device 6 and the cleaning brush of the cleaning mechanism 8. The photoreceptor 3 gradually becomes charged, and as a result, the photoreceptor 3 is electrostatically attracted and fixed to, for example, the fixed master pedestal 9, which hinders the transportation of the photoreceptor 3, or causes wrinkles or tears in the peripheral portion of the photoreceptor 3. Furthermore, the photoconductor 3 has a finite service life and needs to be replaced periodically, but when replacing it, it becomes difficult to remove the photoconductor 3 from the conveying device, or it becomes difficult for the replacement operator to remove it. Disadvantages include the generation of electrical discharge between the hands and fingers, causing discomfort. This drawback is particularly noticeable in a low humidity atmosphere.

The above situation is the same even when the photoreceptor 3 is mounted on the rotating drum 10 as shown in FIG. It is convenient to wind up the rotating drum 10 by sliding the outer circumferential surface of the rotating drum 10 using a winding mechanism provided on the rotating drum 10. requires a very large winding force.

As means for eliminating or alleviating the above-mentioned defects, there are a method of performing conductive processing on the back surface of the photoreceptor to make it conductive, and a method of forming unevenness on the back surface of the photoreceptor to reduce the contact area. . However, all of these means significantly increase the manufacturing cost of the photoreceptor, and the former method has the following drawbacks. For example, when laminating metal foil on the back surface of a photoreceptor, the metal foil comes into contact with the surface of the photoreceptor during the manufacturing process of the photoreceptor, causing scratches and stains on the photosensitive layer, and the metal foil also provides the required flexibility. Furthermore, it is not preferable to form a conductive layer in which conductive powder such as carbon black or metal powder is mixed and dispersed in a resin because the conductive layer is susceptible to bending. Furthermore, for example, when forming a conductive resin layer having an active group or a resin layer containing an activator, the resin having the active group or the activator may adhere to the photosensitive layer during the manufacturing process of the photoreceptor, and the electricity This is undesirable because it reduces the optical characteristics or sensitivity.

On the other hand, in the latter method of forming irregularities on the back surface of the photoreceptor, if the photoreceptors with such irregularities are stacked and stored for a long period of time, the surface smoothness of the photosensitive layer is lost due to the irregularities, and the electrophotography is When subjected to a process, a speckled pattern corresponding to the unevenness appears in the image. In addition, although the effect cannot be obtained unless the unevenness is quite large, it is quite difficult to form such unevenness while maintaining flatness on the back surface of the photoreceptor, which originally requires flatness. .

In view of the above-mentioned circumstances, the present invention has been developed so that even when the photoreceptor is mounted on a photoreceptor conveying device and repeatedly subjected to an actual electrophotographic process, the charging on the back side of the photoreceptor is extremely small and there is no problem in practice, and the invention is extremely inexpensive. An object of the present invention is to provide an electrophotographic photoreceptor that can be manufactured.

Another object of the present invention is to provide an electrophotographic photoreceptor having a support that does not adversely affect the characteristics of the photosensitive layer of the photoreceptor or other photoreceptors during manufacture, storage, and use. be.

Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIG. 3A, a conductive layer 13 made of aluminum foil, for example, is provided on one surface of the base material 11A made of paper, with an adhesive layer 12 made of polyethylene interposed therebetween, and the base material 11A is made of paper. A resin layer 14 containing polyethylene as a main component is provided on the other surface of 11A to constitute a support 15, and light is applied directly onto the conductive layer 13 of this support 15 or through a required intermediate layer 16. The structure is such that conductive photosensitive layers 17 are laminated.

Further, in the present invention, as shown in FIG. 3B or C, a base material 11B made of polyester film is used instead of the base material 11A made of paper in FIG. 3A.
Or base material 11C made of polypropylene film.
Further, polyethylene film, polyethylene terephthalate film, nylon film, acrylic film, and other films may be used alone or in a laminate of two or more types as the base material. Among these, non-hygroscopic substrates are preferred because they do not cause curling due to moisture absorption.

As the material of the conductive layer 13, in addition to aluminum, other metal foils such as zinc and copper can be used. Further, the conductive layer 13 can be formed by depositing a metal film on one surface of the base material or by using a resin in which conductive powder such as metal powder or carbon black is mixed and dispersed, and in this case, the adhesive layer 12 is unnecessary. be.

Further, as the intermediate layer 16 and the photoconductive photosensitive layer, conventionally known ones can be used as they are.

The material of the resin layer 14 provided in the present invention may be a resin containing polyethylene as a main component, that is, a copolymer of ethylene monomer and another resin monomer, or a copolymer of polyethylene and another polymer. Use a mixed resin with coalescence. In the case where a component other than polyethylene is contained, it is necessary that the polyethylene component is contained in an amount of at least 60% or more. Examples of monomers that form copolymers with ethylene include styrenes such as styrene and parachlorostyrene, vinylnaphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, and benzoic acid. Vinyl, vinyl esters such as vinyl butyrate, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloro-ethyl acrylate, phenyl acrylate ,α
- Esters of α-methylene aliphatic monocarboxylic acids such as methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, such as vinyl methyl ether, vinyl isobutyl ether, Vinyl ethers such as vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, N- vinyl pyrrole, N-vinyl carbazole, N-vinylindole, N-vinylpyrrolidone, etc. Vinyl compounds can be mentioned.

Polymers that can be mixed with polyethylene include homopolymers obtained by polymerizing the above-mentioned monomers, copolymers obtained by copolymerizing a combination of two or more of these monomers, or mixtures thereof.
Alternatively, non-vinyl resins such as rosin-modified phenol-formalin resins, oil-modified epoxy resins, polyurethane resins, cellulose resins, and polyether resins, or mixtures of these and vinyl resins as described above can be used.

The polyethylene constituting the resin layer 14 is not particularly limited, but high-density polyethylene with a molecular weight of 30,000 to 100,000 is preferred because of its small coefficient of friction. The thickness of the resin layer 14 is usually 70 μm or less, and the resin layer 14 can be formed by bonding the film to the exposed surface of the base material 11A with an adhesive, or by welding the film. Can be used. Incidentally, carbon black, metal powder, etc. may be mixed and dispersed in this resin layer 14.

Since the electrophotographic photoreceptor of the present invention has the above-described structure, the other surface of the support 15 that supports the photosensitive layer 17 on one side is formed of the resin layer 14 containing polyethylene as a main component. As is clear from the experimental results described below, even when the photoreceptor is repeatedly used in an actual copying machine, the back surface of the photoreceptor, that is, the other surface of the support 15, is hardly charged, and therefore the conveyance of the photoreceptor is There is no fear that an electrostatic adsorption force so large as to inhibit the electrophotographic process may occur, and the electrophotographic process can be stably continued and repeated. Moreover, since polyethylene is a very inexpensive resin and the formation of the resin layer 14 is easy, manufacturing costs can be kept low, and
Polyethylene is an inert, soft resin that does not impair or adversely affect the characteristics of the photosensitive layer of the photoconductor or other photoconductors during production, storage, or use of the photoconductor.

Next, with respect to a specific example of the photoreceptor of the present invention, an experiment conducted in order to confirm the effect of the present invention regarding the charging state on the back surface of the photoreceptor will be described.

Experimental Example 1 According to the configuration shown in FIG. 3A, a support 15 having a resin layer 14 was constructed using a base material 11A made of paper, and a barrier layer made of a hydrophilic resin was placed on the conductive layer 13 as an intermediate layer. 16, while a photoconductive powder consisting of zinc oxide powder was mixed and dispersed in a binder resin consisting of silicone resin, ethyl cellulose and acrylic resin together with a sensitizer consisting of rose bengal using a ball mill;
The obtained photosensitive liquid was applied onto the intermediate layer 16 and dried to form a photosensitive layer 17, thereby producing an electrophotographic photoreceptor according to the present invention. This photoreceptor was cut into required dimensions and attached to the conveyance device of a copying machine having the endless belt 2 shown in FIG. The adsorption force of the photoreceptor to No. 9 was measured. That is, after removing the mounting tool for the endless belt 2 of the photoreceptor, one end of the photoreceptor is pulled in the direction of extension of the photoreceptor using a spring weight, and when the photoreceptor starts sliding on the fixed master mount 9, the photoreceptor is removed. The tensile load applied to the was read using a spring balance. The value was extremely small, ranging from 50 to 100 g.

The above experiments were conducted in an atmosphere at a temperature of 10 to 15° C. and a relative temperature of 20%, and a spring balance manufactured by Ohba Instruments Manufacturing Co., Ltd. was used.

On the other hand, as shown in FIG. 4A, an intermediate layer 16 and a photosensitive layer 17 were provided in exactly the same manner as described above on a support having the same structure except that a polypropylene layer 18 was provided in place of the resin layer 14. When a photoreceptor was made using the above method and the tensile load was determined in the same manner as above, the value was as large as 3000 g.

Experimental Example 2 According to the structure shown in FIG. 3B, a support 15 having a resin layer 14 was constructed using a base material 11B made of a polyester film, and a photosensitive layer was formed in the same manner as in Experimental Example 1 to obtain the present invention. A photoreceptor was fabricated using the following method. On the other hand, as shown in FIG. 4B, a photoreceptor was prepared in the same manner using a support without the resin layer 14.

The tensile strength of each of these photoreceptors was determined in the same manner as in Example 1, and the tensile strength of the photoreceptor having the resin layer 14 according to the present invention was 50 to 100.
However, for the photoreceptor without the resin layer 14, it was 550 g.

Experimental Example 3 According to the structure shown in FIG. 3C, a support 15 having a resin layer 14 was constructed using a base material 11C made of a polypropylene film, and a photosensitive layer was formed in the same manner as in Experimental Example 1 to obtain a photosensitive layer according to the present invention. A photoreceptor was produced. On the other hand, as shown in FIG. 4C, a photoreceptor was prepared in the same manner using a support without the resin layer 14.

When the tensile strength of each of these photoreceptors was determined in the same manner as in Experimental Example 1, it was found that the resin layer 14
The amount was 50 to 100 g for the photoreceptor having a resin layer, and 550 g for the photoreceptor without a resin layer.

As is clear from the above experiments, in the electrophotographic photoreceptor of the present invention, in which the back surface opposite to the photosensitive layer is formed of the resin layer 14 made of polyethylene, even when it is used repeatedly, there is very little charge. There is virtually no obstacle to this. The theoretical reason for this is unknown, but the friction is due to the fact that polyethylene itself is difficult to charge and the surface of the resin layer 14 loses its smoothness considerably due to containing polyethylene as a main component. This is thought to be due to the fact that it is less likely to occur.

As described above, according to the present invention, an extremely simple structure in which a resin layer containing polyethylene as a main component is exposed on the back surface of an electrophotographic photoreceptor reliably and significantly prevents charging of the photoreceptor, and is suitable for actual use. It is possible to prevent troubles such as electrostatic adhesion on the top of the photoreceptor, and since there is almost no static charge, the photoreceptor can be easily removed for replacement. It is possible to provide an electrophotographic photoreceptor that is completely unnecessary, has low cost, and has no adverse effects in manufacturing, storage, or use.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a photoconductor conveyance device using an endless belt of an electronic copying machine, FIG. 2 is an explanatory cross-sectional view of a conveyance device also using a rotating drum, and FIG. FIGS. 3B and 3C are explanatory cross-sectional views showing the structure of the support, respectively, and FIG. 4A is a comparative sample of the photoreceptor of FIG. 3A. FIGS. 4B and 4C are explanatory cross-sectional views showing the structure of the photoreceptor, and FIGS. 4B and C are explanatory cross-sectional views of a support for constructing a comparative sample of the photoreceptor using the supports of FIGS. 3B and C, respectively. DESCRIPTION OF SYMBOLS 1...Pulley body, 2...Endless belt, 3...Electrophotographic photoreceptor, 4...Charging device, 5...Exposure mechanism, 6...Developing device, 7...Transfer pole, 8...Cleaning mechanism, 9...Fixed master mount, 10... Rotating drum, 11A, 1
1B, 11C... Base material, 13... Conductive layer, 14... Resin layer, 15... Support, 17... Photosensitive layer.

Claims (1)

[Claims] 1 Consisting of a support and a photoconductive photosensitive layer laminated on one side of the support, the other side of the support is formed of a resin layer containing polyethylene as a main component, and is repeatedly exposed to electrons. An electrophotographic copying master paper characterized in that it is used in a photoforming process.