JPH07319191A - Aluminum tube for photoconductor substrate and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To obtain an aluminum tube for a photoreceptor base at low cost which realizes excellent picture quality and to obtain its production method. CONSTITUTION:This aluminum tube for a photoreceptor base body is produced by drawing an extruded raw tube. The max. recess on the tube surface is specified to <5mum width, <15mm length and <15mum thickness. This aluminum tube for the photoreceptor base body is produced by subjecting the extruded raw tube to the treatment to remove die marks. In the treatment, depth of the die mark on the tube surface is reduced to half or smaller to obtain <=3mum surface roughness Rmax. Then the tube is subjected to cold drawing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor base aluminum tube used as a conductive support for supporting a photoconductor in an electrophotographic copying machine, a laser beam printer and the like, and a method for producing the same. In this specification, the term aluminum is used to include both aluminum and aluminum alloys.

[0002]

2. Description of the Related Art It is desirable that the aluminum tube for a photoconductor substrate as described above has a surface state relatively close to a mirror surface due to its properties. For this reason, conventionally, aluminum pipes have been mirror-finished by cutting, but it is difficult to cut the aluminum pipes that are long, so it is necessary to cut the aluminum pipes short, which is a factor of cost increase. Was becoming. Therefore, recently, a processing method called ED method has been adopted in which aluminum is extruded into a tubular body and then the extruded raw tube is drawn to obtain a mirror surface. The ED method has an advantage that a relatively good mirror surface state can be obtained at a low cost because the extruded tube can be drawn to a length of 2 to 3 times by one or more drawing processes.

[0003]

However, although the aluminum tube for a photoreceptor substrate manufactured by the conventional ED method is low in cost, it is inferior in specularity as compared with a machined mirror-finished aluminum tube. , After coating the photoreceptor through resin coating or anodizing base treatment,
When incorporated into a printing apparatus and printed, an image defect may occur and there is a problem in image quality. SUMMARY OF THE INVENTION The present invention aims to solve the above problems by providing an aluminum tube for a photoconductor substrate which is low in cost and excellent in image quality, and a method for manufacturing the same.

[0004]

When the inventors investigated the cause of the above-mentioned image defects, the die marks existing on the surface of the extruded raw tube became elongated and relatively large concave streaks due to drawing, and this is the cause. It was found that this caused image defects. Then, as a result of investigating the size of the dent on the surface of the aluminum tube for the photoconductor substrate that causes an image defect, if the size of the dent is less than a certain value, the photoconductor is coated with a resin or a base coating, It was found that the cavities were easily filled and did not result in a final defect. Of the die marks on the surface of the extruded raw pipe, small and shallow ones disappear or become fine dents by drawing, and the extruded pipe before drawing does not become a final defect because it is easily embedded by the base treatment. It was found that the aluminum tube for a photoconductor substrate having a size of the surface recessed by a certain amount or less can be obtained by pulling out if the surface roughness of the above is regulated to some extent, and the present invention has been completed.

That is, the aluminum tube for a photoconductor substrate of the present invention is an aluminum tube produced by drawing an extruded raw tube, and the recess of the tube surface has a width of less than 5 μm and a length of 15 m.
It is characterized by being regulated to less than m and a depth of less than 15 μm. Further, in the method for manufacturing an aluminum tube for a photoreceptor substrate, a die mark removal treatment for reducing the depth of die marks on the tube surface to less than half is performed on an extruded raw tube to reduce the surface roughness to Rmax 3 μm or less, It is characterized by performing cold drawing.

The material of the aluminum tube for the photoreceptor substrate according to the present invention is Al-Mn alloy, pure Al, Al-
Examples thereof include Mg-Si alloys and Al-Mg alloys, and it is desirable to use an extruded raw pipe from a cast billet that has been sufficiently molten.

In the above-mentioned aluminum tube for a photoconductor substrate, if the dents existing on the surface are sufficiently small,
A final defect is not reached by being embedded by coating the photoreceptor or resin coating as a base treatment. Therefore, the size of the recess must be restricted to a width of less than 5 μm, a length of less than 15 mm and a depth of less than 15 μm. The preferred size of the depression is less than 4 μm in width, less than 5 mm in length and less than 10 μm in depth.

By the way, when the extruded raw pipe is pulled out, the extruded raw pipe is stretched and the diameter of the pipe is reduced, so that the surface layer of the pipe is stretched and the opening (1) of the recess is closed as shown in FIG. Deformation occurs in the direction (arrow direction in the figure). In addition, when the outer diameter reduction rate due to drawing is represented by the following formula [I], the extruded raw tube is usually 10 times when the aluminum tube for the photoreceptor substrate is manufactured.
It is drawn with a high outside diameter reduction rate of over%. In such drawing, a relatively small dent disappears or becomes smaller due to the deformation of the surface layer portion, but a large dent has a large amount of deformation in the direction in which the opening (1) of the dent is closed, and therefore the dent is large. Has a smaller width but a larger depth. According to the present invention, the size of the recess of the extruded raw pipe is set to a certain value or less before the drawing process, so that the surface of the aluminum pipe for the photoconductor substrate can be drawn even if the drawing is performed at such a high outer diameter reduction rate. The size of the recess existing in the
It can be less than μm, less than 15 mm in length and less than 15 μm in depth. That is, the extruded raw tube is subjected to a die mark removal treatment to reduce the depth of the die mark to less than half and the surface roughness is set to Rmax of 3 μm or less. The size of the dents within the range is within the above-mentioned range, and has a good mirror surface. Particularly, the surface roughness (Rmax) is preferably 2 μm or less. Outer diameter reduction rate (%) = {(extruded raw pipe outer diameter-drawn pipe outer diameter) / extruded raw pipe outer diameter} x 100 ... [I]

Specific methods of the die mark removal treatment include a method of grinding the surface with a rotating brush, a method of etching after grinding with a grindstone or buffing, and a method of cold drawing to reduce the outer diameter to 10% or less. Three methods can be recommended.

The grinding with the first rotary brush is to grind the tube surface while rotating the wire brush. For example, in the rotating brush shown in FIG. 2, the revolution plate (2)
A plurality of donut-shaped wire brushes (3) that can rotate on the top are attached, and each wire brush (3) is revolved while revolving, and the surface of the extruded raw pipe is brought into contact with these wire brushes (3) and the pipe is By rotating, the tube surface is ground. In order to keep the surface of the extruded raw tube within the above range, it is preferable to use a thin wire brush having a diameter of 0.5 mm or less.
Although many fine scratches may be generated by brush grinding for removing the die mark, these scratches are so small that they disappear due to drawing or coating of the photoconductor, and image defects during printing. Don't

In the case of the second grindstone grinding or buffing,
If the abrasive grains or polishing agent remain in the dents on the surface, it may become a large defect due to the subsequent drawing process,
It is necessary to remove the abrasive grains and the polishing agent by etching after grinding or polishing. It is preferable to use a grindstone having a roughness of about # 500 to # 1500 so that the surface of the extruded raw tube is within the above range. It suffices that the etching removes the abrasive grains and the polishing agent remaining on the tube surface, and the type of etching solution and other conditions are not limited.

In the third cold drawing method, the surface diameter of the pipe is deformed so as to be stretched and scraped off by performing drawing with a small outer diameter reduction rate represented by the above-mentioned formula [I], and the depth of the die mark. Has the effect of reducing. However, if the outer diameter reduction rate is too large, the deformation becomes more noticeable in the direction of closing the opening (1) of the die mark than the effect of scraping off the surface layer, and the depth may be rather deep even if the width of the recess is narrowed. There is. Therefore, in order to remove the die mark, it is necessary to perform light drawing with a reduction rate of the outer diameter of 10% or less. A preferable outer diameter reduction rate is 5% or less.

[0013]

The aluminum tube for a photoreceptor substrate according to the present invention is an aluminum tube manufactured by pulling out an extruded raw tube, and the recess on the tube surface has a width of less than 5 μm and a length of 1
Due to the regulation of less than 5 mm and a depth of less than 15 μm, the depressions are only small. Therefore, the recesses are easily embedded and disappear by coating the photoreceptor or resin coating as the base treatment.

Further, in the method of manufacturing an aluminum tube for a photoreceptor substrate, a die mark removing treatment for reducing the depth of the die mark on the tube surface to less than half is performed on the extruded raw tube before cold drawing to obtain a surface roughness. Since Rmax is set to 3 μm or less and a remarkably large dent is removed, the dent after the withdrawal is small within the above range.

The die mark removal treatment of the extruded raw pipe is performed by grinding the pipe surface with a rotating brush, etching the pipe surface after grinding with a grindstone or buffing, or by cold drawing with an outer diameter reduction rate of 10% or less. Therefore, it can be easily performed.

[0016]

EXAMPLES Next, specific examples of the aluminum tube for a photoconductor substrate and the method for manufacturing the same according to the present invention will be described.

In each of the examples and comparative examples, as a material for manufacturing an aluminum tube for a photoconductor substrate, an outer diameter of 40 mm, an inner diameter of 36 mm, and a surface roughness (R
max) 5 μm extruded raw tube was used. First, the following die mark removal treatment was performed on the extruded raw pipe. (Example 1) The depth of the die mark was ground to 60% by the rotating brush shown in FIG. (Example 2) The same rotary brush as in Example 1 was used for grinding until the depth of the die mark was 100%, in other words, the die mark disappeared. (Example 3) After the surface of a pipe was ground with abrasive grains having a roughness of # 1000, etching was performed with a sodium hydroxide solution. (Example 4) Cold, outer diameter 38.5 mm, inner diameter 35.5
drawn to mm. The outer diameter reduction rate at this time is 3.75%. (Comparative Example) No die mark removal treatment was performed. Then, after measuring the surface roughness (Rmax) of each extruded tube that has been subjected to the die mark removal treatment as described above, cold drawing is performed for two passes using a mandrel to obtain an outer diameter of 30 m.
The aluminum tube for a photoreceptor base having a diameter of m and an inner diameter of 28.5 mm was finished, and the surface was observed with a microscope to measure the width and length of the maximum dent and the depth by the depth of focus method. Furthermore, the same photoconductor was applied to the surface of each aluminum tube for each photoconductor substrate, and the print quality was evaluated by visual observation by incorporating the photoconductor in a printing device. Table 1 shows the reduction rate of the die mark depth and Rma after the die mark removal treatment.
x, and the size of the largest depression in the final drawn tube, image quality.

[0018]

[Table 1]

As is clear from the results shown in Table 1, Example 1
Each of the aluminum pipes for a photoreceptor substrate manufactured in any of Nos. 4 to 4 had a maximum recess of less than 5 μm in width, less than 15 mm in length and less than 15 μm in depth, and high-quality printing without image defects could be performed. On the other hand, in the aluminum tube for a photoreceptor substrate of the comparative example, image defects occurred.

[0020]

As described above, the aluminum tube for a photoreceptor substrate of the present invention is an aluminum tube manufactured by pulling out an extruded raw tube, and the maximum recess on the tube surface has a width of 5 mm.
Since it is regulated to less than μm, less than 15 mm in length and less than 15 μm in depth, the dent disappears by coating the photoreceptor or resin coating as a base treatment. as a result,
The dent does not reach the final defect and can provide a high quality image.

Further, in the method for producing an aluminum tube for a photoreceptor base, the extruded raw tube was subjected to a die mark removal treatment for reducing the depth of the die mark on the tube surface to less than half, and the surface roughness was set to Rmax of 3 μm or less. After that, since cold drawing is performed, the recess of the surface of the extruded raw pipe can be made small within the above range after the drawing. Therefore, it is possible to manufacture an aluminum tube for a photoreceptor base that can provide a high quality image as described above.

Further, the die mark removal treatment of the extruded raw pipe is performed by grinding the pipe surface with a rotating brush, etching the pipe surface after grinding with a grindstone or buffing, or by cold drawing with an outer diameter reduction rate of 10% or less. It can be carried out by any of the methods, and in each case, a simple process is added before the drawing, and an aluminum tube for a photoconductor substrate having excellent image quality can be efficiently manufactured. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an extruded raw pipe.

FIG. 2 is a schematic front view of a rotating brush.

[Explanation of symbols]

 1 ... Aperture 2 ... Revolution plate 3 ... Wire brush

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruo Tate, 6-224, Kaiyamacho, Sakai City, Showa Aluminum Co., Ltd. (72) Inventor Takeshi Gocho, 6-224, Kaiyamacho, Sakai City

Claims (5)

[Claims] 1. An aluminum tube manufactured by pulling out an extruded raw tube, wherein a recess on the surface of the tube is restricted to a width of less than 5 μm, a length of less than 15 mm and a depth of less than 15 μm. Aluminum tube for body foundation. 2. The extruded raw pipe is subjected to a die mark removal treatment for reducing the depth of the die mark on the pipe surface to half or less to reduce the surface roughness to Rmax 3 μm or less, and then cold drawn. Method for manufacturing aluminum tube for photoconductor substrate. 3. The method for manufacturing an aluminum pipe for a photoconductor substrate according to claim 2, wherein the die mark removing process is performed by grinding the pipe surface with a rotating brush. 4. The method for manufacturing an aluminum tube for a photoconductor substrate according to claim 2, wherein the die mark removing process is performed by etching the tube surface after grinding with a grindstone or buffing. 5. The method for manufacturing an aluminum tube for a photoconductor substrate according to claim 2, wherein the die mark removing process is performed by cold drawing with an outer diameter reduction rate of 10% or less.