JPH08171223A - Method for extruding aluminum material for electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To extrude an aluminum tube stock for an electrophotographic photoreceptor with less defects. CONSTITUTION: The rear end of the aluminum billet 1 placed in a container is cut with a butt end shear 5, a fresh aluminum billet 1 is brought into contact with the cut face, and the billet is continuously extruded to produce an aluminum material for an electrophotographic photoreceptor. In this case, the surface roughness of the cut face and the end face of the fresh billet 1 to be brought into contact with the cut face is controlled to <= about 100μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extruding an aluminum material, and more particularly to a method for extruding a blank of an aluminum base used as a conductive support of an electrophotographic photoreceptor from a billet.

[0002]

2. Description of the Related Art Conventionally, a cylindrical aluminum substrate made of aluminum or an aluminum alloy has been used as a conductive support for an electrophotographic photosensitive member. There are various methods for producing the cylindrical aluminum substrate, and one of them is extrusion of a cylindrical aluminum base, an aluminum billet, using a porthole die to form a cylindrical aluminum tube. Then, if necessary, the aluminum base tube is subjected to a treatment such as squeeze processing and surface treatment to produce a conductive support, and then, if necessary, subjected to surface oxidation treatment, and then the surface of the conductive support. There is a method for producing an electrophotographic photosensitive member by forming a photosensitive layer on.

This extrusion method is usually carried out using an apparatus provided with a die ring incorporating a container (2) and a porthole die (4) as shown in FIG. 1 and processed by an aluminum billet. (1) is conveyed in the container (2) from the right side to the left side in the figure, and is pressed by the port hole die (4) under high temperature and high pressure.

The porthole die (4) is a short-axis columnar body having an open porthole with a large inlet portion and a small outlet portion. The aluminum billet (1) is once separated and then flows in from the inlet of the porthole. It recombines through a small gap at the outlet of the port hole and is extruded as a thin-walled cylindrical aluminum tube. Then, when one aluminum billet is extruded, as shown in FIG. 2, the rear end portion is cut by a certain amount with a cutting blade called a bad end shear (5),
After that, the next new aluminum billet is extruded so as to connect to the cut surface.

[0005]

By the way, when an aluminum tube formed by such a processing method is used as a support for an electrophotographic photosensitive member, a microdefect which is not a problem with a normal aluminum profile is generated. When it is present on the support, there is a problem that it causes an image defect during image formation on the photoreceptor. Therefore, in the conventional photoconductor manufacturing process, in order to remove the photoconductor having such micro defects,
Although almost all of them are inspected for surface defects, since such inspection is usually performed after applying the photosensitive layer, not only is the extra human cost involved in the inspection, but the defect occurrence rate is high. However, since a considerable amount must be discarded as defective products, there is a problem that the yield is low and the manufacturing cost is very high.

The present invention is intended to solve the above problems, and an object thereof is to provide an electrophotographic photoreceptor having reduced image defects, and an electrophotographic photoreceptor having reduced defects. An object of the present invention is to provide a method for extruding an aluminum tube. Then, by obtaining an aluminum base pipe in which the occurrence rate of the defects is reduced, the production efficiency of the aluminum base pipe and the production efficiency of the electrophotographic photosensitive member can be improved.

[0007]

As a result, the inventors of the present invention have made diligent studies to solve the above-mentioned problems, and as a result, the rate of occurrence of such defects was found to be such that cutting after cutting with the bad end shear of the front billet at the billet joint portion. Surface and the surface roughness of the front end surface of the next billet, and by controlling the surface roughness below a specific value and extruding the aluminum billet, the above defects are reduced and good electrophotography The inventors of the present invention have arrived at the present invention by discovering that an aluminum tube capable of producing a photoconductor can be obtained.

That is, the gist of the present invention is that the rear end of the aluminum billet loaded in the container is cut with a bad end shear, and a new aluminum billet is brought into contact with the cut surface to continue extrusion processing. In the method of extruding an aluminum material for use in electroforming, the extruding method of an aluminum material for an electrophotographic photosensitive member, characterized in that the cut surface and an end surface of a new aluminum billet contacting the cut surface are brought into contact with each other with a surface roughness of 50 μm or less. In the way.

[0009]

The present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an extrusion processing apparatus used in the present invention, and FIG. 2 is a cross-sectional view showing a method of cutting the rear end of a front billet with a bad end shear.

The extrusion apparatus illustrated in FIGS. 1 and 2 is provided with a cylindrical container (2) and a die ring incorporating a porthole die (4), and an aluminum billet (1) to be extruded. Is transported in this container from the right side in the figure, passes through the porthole die under high temperature and high pressure, and is then transported to the left side in the figure. The aluminum billet is separated and flows in through the inlet of the port hole, and is pressed and joined through a small gap at the outlet of the port hole to be extruded as a thin-walled cylindrical aluminum tube.

When one aluminum billet is extruded,
The rear end is usually cut within a range of 20 mm or less, and then the next aluminum billet is extruded so as to be connected to it. The feature of the present invention resides in that the surface roughness of the cut surface of the front billet and the surface roughness of the front end surface of the next aluminum billet are set to a certain level or less.

Here, the surface roughness means JIS B065.
Rma judged by the standard surface roughness standard piece according to 9
Say x (μ). In the present invention, the surface roughness of the bad end shear cut surface of the front billet is about 100 μ or less, preferably about 70 μ or less, and more preferably about 50 μ or less. On the other hand, the surface roughness of the front end face of the next billet is about 100 μ or less, preferably about 70 μ or less, and more preferably about 50 μ or less. If the surface roughness is too large, air gaps in the connecting surface between the cut surface and the front end surface become 10 μm or more, which is a problem as a defect of the tube for the photoreceptor substrate.

As a method for reducing the surface roughness of the cut surface of the front billet to 100 μm or less in the present invention, the conventional bad end shear (the shear for ordinary aluminum material can obtain the surface roughness of only about 500 μ) is cut. The blade shape may be improved so that the surface roughness becomes 100 μ or less, or after cutting, special processing for smoothing the surface, for example, milling, polishing, etc. may be performed. It is good, but usually, the extruding rear end of the front billet has a high extruding temperature (about 500 ° C.), so that it is preferable to use a special bad end shear.

Further, as a method for making the surface roughness of the front end face of the next billet of 100 μm or less in the present invention, milling, polishing, cutting with a saw machine using a special saw blade, etc. are mentioned, but especially It is preferable to use milling. Normally, when cutting with a face mill, 20 to 3
The surface roughness is 0 μ. As the aluminum billet used in the present invention, various known aluminum alloys are used in addition to ordinary aluminum alone.

[0015]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. [Comparative Example 1] A billet having an outer diameter of 177 mm and a length of 500 mm is inserted into a container, pushed by a push rod, and a hollow pipe having a diameter of about 40 mm is pushed out by about 40 m by passing through a die. At this time, do not press the billet against the die completely
Leave about 0 mm. Next, the container was moved to the right in the figure, and the remaining billet (bad end) was cut off with a conventional bad end shear from above.
Looking at the cut surface at this time, the surface roughness was about 500 μ, and it was a torn shape, and the surface was rough. Next, press the container against the die, insert a new billet with a surface roughness of about 500μ whose front end face was cut with a saw, and push it in with a push rod. Then, extrusion processing was performed.

The aluminum tube obtained by the extrusion is ironed and formed into a thin long-axis cylinder, and then oxytitanium phthalocyanine and polyvinyl butyral are placed on the surface-treated conductive support. A charge generating layer containing a resin and a charge transporting layer containing a hydrazone compound and a polycarbonate resin were laminated by a dip coating method to produce an electrophotographic photoreceptor.

At this time, the cavity defects of the photosensitive drum frequently occurred especially in front of the extruded tube, and the total occurrence rate was about 4 to 8%. [Example 1] The same billet as in Comparative Example 1 was inserted into a container, pushed with a push rod, and passed through a die to obtain about 40.
A hollow pipe of mmφ is extruded for about 40 m. At this time, the billet is not completely pressed against the die, and about 20 mm is left. Next, move the container to the right in the figure, and cut off the remaining billet (bad end) from the top with a bad end shear that has been precision processed. Looking at the cut surface at this time, the surface roughness was 50 μ. Next, press the container against the die, cut the front end face with a saw machine, insert a new billet processed with a face mill to a surface roughness of 30μ, and push it in with a push rod. The front end face was pressed and joined to perform extrusion processing.

The aluminum tube obtained by the extrusion is ironed to form a thin long-axis cylinder, and then oxytitanium phthalocyanine and polyvinyl butyral are placed on the surface-treated conductive support. A charge generating layer containing a resin and a charge transporting layer containing a hydrazone compound and a polycarbonate resin were laminated by a dip coating method to produce an electrophotographic photoreceptor. At this time, the cavity defect of the photosensitive drum was 1% or less as a whole.

[0019]

As described in detail above, according to the present invention, an aluminum photographic tube having an extremely low defect rate can be obtained, so that an electrophotographic photosensitive member having excellent characteristics with few image defects can be obtained.
Further, since the range of the defective portion is reduced, the portion to be removed and eliminated is reduced and the manufacturing efficiency of the aluminum base pipe is improved.
Further, the number of defective products conventionally found after forming the photosensitive layer is reduced, and the production efficiency of the electrophotographic photoreceptor is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an extrusion processing device.

FIG. 2 is a cross-sectional view showing a method of cutting the rear end of the front billet after extrusion.

[Description of sign]

 1: Aluminum billet 2: Container 3: Push rod 4: Dice 5: Bad end shear

Claims (1)

[Claims] 1. Extrusion of an aluminum material for an electrophotographic photosensitive member in which a rear end of an aluminum billet loaded in a container is cut by a bad end shear, and a new aluminum billet is brought into contact with the cut surface to continue extrusion processing. In the processing method, the aluminum material for an electrophotographic photosensitive member is extruded by bringing the cut surface and a new aluminum billet in contact with the cut surface into contact with each other with a surface roughness of about 100 μm or less.