JPS58175Y2 - electrophotographic photoreceptor - Google Patents

Description

[Detailed description of the invention] The present invention has a photoconductive layer on a support having grooves or notches with a substantially arcuate cross section at both ends, and at least a surface layer such as the photoconductive layer is formed on the support. The present invention relates to an electrophotographic photoreceptor characterized in that they are mutually present on almost the entire surface.

Electrophotographic photoreceptors such as zinc oxide to resin binder dispersion systems and organic photoconductive systems are generally coated on a drum-shaped or plate-shaped support by means of wire bars, roller coating, brush coating, spraying, etc. to form a photoconductive layer. Although it is manufactured by applying a photosensitive liquid, it is difficult to finish the surface of the photoconductive layer neatly with this method, and a product with high commercial value cannot be obtained, and there are also problems with durability when used repeatedly. becomes.

Therefore, in order to obtain a photoreceptor with a uniform and flat surface layer,
For example, Japanese Patent Publication No. 51-4110 discloses a method in which a drum-shaped support containing a liquid with a large heat capacity such as water is immersed in a photosensitive liquid, and then pulled up vertically with the liquid flowing down slightly and dried. In JP-A No. 49-107244, a photosensitive liquid is coated on a drum-shaped support by a conventional method and dried.
Furthermore, after applying an adhesive thereon, a heat-shrinkable plastic tube is covered as a protective layer, and then this is heat-shrinked to bring the tube into close contact with the surface of the photoconductive layer.

However, in the former immersion pulling method, during pulling, the photosensitive liquid flows down the support and concentrates at the bottom edge of the coated surface, causing the coating film to bulge in that area, resulting in uneven thickness of the photoconductive layer. This not only deteriorates image stability (uniformity of image density, uniformity of background density), but also causes mechanical trouble within the copying machine, and when drying, heat shrinkage of the coating film causes raised areas. Internal stress is generated in this area, making it easy to peel or sink.

Although it is possible to apply the photosensitive liquid without it flowing down, in order to make the coating uniform as a whole, it is necessary to
It is preferable to adjust the viscosity of the liquid, drying conditions, support temperature, etc., and apply the liquid in a slightly flowing state.

On the other hand, in the latter method of using a heat-shrinkable tube, a uniform and flat surface layer is obtained by heat-shrinking the tube, and the coating film is also reinforced by the tension generated by the heat-shrinking of the tube, but the axis of the tube Adhesion to the coating film (photoconductive layer) is still insufficient at both end portions of the tube, resulting in drawbacks such as curling or tearing of the tube and permeation of the solvent.

The present invention eliminates all of the above-mentioned drawbacks, and has excellent image stability, no trouble in the copying machine, no peeling of edges, etc.
An object of the present invention is to provide an electrophotographic photoreceptor that exhibits excellent adhesion and durability without curling, tearing, etc., and without solvent seepage.

To explain the photoreceptor of the present invention with reference to the drawings, FIGS. 1 to 4 are longitudinal cross-sectional views of an example of the photoreceptor of the present invention, and 1 is a drum-like shape having grooves or arrowheads with a substantially arcuate cross section at both ends. The support 1' is also a plate-like support, 2 is a photoconductive layer, and 3 is a protective layer (also called an overcoat layer or an insulating layer).

In the photoconductor shown in FIGS. 1 and 4, the photoconductive layer 2 is the surface layer, and the photoconductive layer 2 is the surface layer, and
In the photoreceptor shown in the figure, the protective layer 3 is the surface layer.

In any photoreceptor, at least the surface layers are present on almost the entire surface of the support.

Note that the photoreceptors shown in FIGS. 1 to 3 use a drum-shaped support, and the photoreceptor shown in FIG. 4 uses a plate-like support.

To make a photoreceptor as shown in FIGS. 1 and 4, a photoreceptor may be applied and dried on a drum-shaped support 1 or a plate-shaped support 1' according to the above-mentioned immersion pulling method (however, the In the case of the photoreceptor shown in the figure, only one side of the support is immersed using an appropriate method).

In the case of the photoreceptor shown in FIG. 2, a photoconductive layer is provided on the drum-shaped support 1 by a conventional method such as vapor deposition or coating, and then a suitable layer is formed on the photoconductive layer by the same dipping and pulling method as in the case of FIG. A resin solution may be applied and dried.

Alternatively, in the case of the photoreceptor shown in FIG. 3, a photoconductive layer may be provided on the drum-shaped support 1 by a conventional method such as vapor deposition or coating, and then covered with a heat-shrinkable tube and heat-shrinked.

In addition, a photoconductor and a resin binder for forming a photoconductive layer,
The material for the protective layer resin (or heat-shrinkable tube) may be any conventionally used material, but it is preferable that the heat-shrinkable tube shrinks in the axial direction to further improve adhesion. .

The shape of the end portion of the support body is preferably as shown in FIGS. 2 and 3 rather than as shown in FIGS. 1 and 4.

Further, the shape of the support itself is not limited to those shown in FIGS. 1 to 4.

Note that a known sensitizer can be added to the photoconductive layer.

Further, an intermediate layer such as an adhesive layer can be provided between the support and the photoconductive layer or between the photoconductive layer and the protective layer.

This intermediate layer may or may not extend to the grooves or notches of the support.

Examples are shown below.

Example 1 An aluminum drum having an outer diameter of 120 mm and a length of 310 mm and having grooves in the circumferential direction at both longitudinal ends as shown in FIG. Pull up vertically at a speed of 30 mm/sec, then 11
It was dried at 0° C. for 10 minutes to obtain a drum-shaped photoreceptor as shown in FIG. 1 having a photoconductive layer with a thickness of 10 μm on the flat surface.

At this time, the height of the bulge at the end was 2 to 3 .mu.m from the flat surface of the photoconductive layer, as shown in FIG.

On the other hand, a comparison photoreceptor having a photoconductive layer with a flat portion having a thickness of 10 μm was prepared in the same manner as in the present example except that an aluminum drum without grooves was used.

The maximum height of the end portion of this product was 30 to 40 μm from the flat surface of the photoconductive layer, as shown in FIG.

In FIG. 6, 1'' is a drum-shaped support without grooves, and 2' is a photoconductive layer.

Example 2 After processing both ends of an aluminum drum with an outer diameter of 120 mm and a length of 31 Q mm into the shape shown in FIG.
10' Torr, support temperature 60°C, evaporation source temperature 250
It was deposited to a thickness of about 50μ at ~300°C, and then a protective layer solution with the following composition was applied using the same dipping and pulling method as in Example 1 to form a protective layer with a thickness of 2μ, as shown in Figure 2. I created a photoreceptor like this.

The end portion of the obtained photoreceptor was as shown in FIG. 9, and no swelling or peeling of the protective layer was observed.

On the other hand, the end of the photoreceptor produced in the same manner as in this example except that an aluminum drum without notches was used is shown in FIG. 10, and the maximum height of the protrusion from the flat part of the protective layer 3' is 1
It was 0-15μ.

Further, peeling of the protective layer was observed up to about 2 mm from the outermost edge.

Example 3 Epoxy resin (Epicoat 1001 manufactured by Shell Oil Company, USA)
) 150 g dissolved in 600 g of methyl ethyl ketone, 100 g of photoconductive copper phthalocyanine particles were added, mixed and dispersed in a ball mill for 4 hours, 15 g of diethyltetramine (curing agent) was added thereto, and further mixed and dispersed in a ball mill for 3 minutes. After that, the end part was processed into the shape shown in Fig. 11 with an outer diameter of 120 mm and a length of 31 Q mm.
■Apply it on an aluminum drum and heat it with hot air at 50℃ for 2 hours.
The photoconductive layer was dried for 0 minutes to form a 20 μm thick photoconductive layer, and then left at room temperature for one week to harden the photoconductive layer.

Next, a heat-shrinkable plastic tube (HHS Diafoil made by Mitsubishi Plastics) with a film thickness of 15 μm is placed on top of this, heat-shrinked to provide a protective layer, and the end shape of the photoreceptor (3 (corresponding to the photoreceptor shown in the figure) was obtained.

On the other hand, a comparative photoreceptor was prepared in the same manner as in this example except that an aluminum drum having no notches was used.

The shape of the end portion is as shown in FIG.

Next, when these photoreceptors were used to make continuous copies using a commercially available wet-type electrophotographic copying machine, the photoreceptor of this example exhibited no peeling or tearing of the protective layer until 20,000 copies were obtained.
In addition, there was no penetration of the developer from the edge, whereas with the comparison product, the protective layer tore and peeled off to about 2 mm from the edge after making the same number of copies, and the developer also penetrated 1Qmm from the edge. It had penetrated all the way.

[Brief explanation of drawings]

1 to 4 are longitudinal sectional views of an example of the photoreceptor of the present invention, and Fig.
The figure is a sectional view showing the dimensions of the end of the support of the present invention used in Example 1, Figure 6 is a state diagram of the end of the photoreceptor of the present invention obtained in Example 1, and Figure 7 is an example of the present invention. 8 is a cross-sectional view showing the dimensions of the end of the support of the present invention used in Example 2, and FIG. 9 is a state diagram of the end of the comparative photoreceptor obtained in Example 2. A state diagram of the end portion of the photoreceptor of the present invention, FIG. 10 is Example 2.
FIG. 11 is a cross-sectional view showing the dimensions of the end of the support of the present invention used in Example 3, and FIG. 12 is a state diagram of the end of the comparative photoreceptor obtained in Example 3. FIG. 13 is a state diagram of the end portion of the photoreceptor of the present invention, and FIG. 13 is a state diagram of the end portion of the comparative photoreceptor obtained in Example 3. 1...Drum-shaped support of the present invention, 1'...
...Plate-shaped support of the present invention, 1''...Drum-shaped support for comparison, 2゜2'...Photoconductive layer, 3,3'
...protective layer.

Claims (1)

[Scope of utility model registration request] A photoconductive tank is provided on a support having grooves or notches with substantially arc-shaped cross sections at both ends, and at least surface layers such as photoconductive layers are mutually present on substantially the entire surface of the support. An electrophotographic photoreceptor characterized by: