JPH0635216A - Production of aluminum tubular substrate for electro-photographic photosensitive body - Google Patents

Abstract

PURPOSE:To obtain an aluminum substrate being excellent in an interference fringe preventive effect with respect to a photosensitive body to which a coherent light of a laser light, etc., is an exposure light source by performing centerless grinding and its moderate honing processing as the subsequent surface treatment to the aluminum substrate for an electrophotographic photosensitive body. CONSTITUTION:With respect to an aluminum tubular base body having prescribed surface roughness, manufactured by extrusion and drawing, the surface roughness of the aluminum tubular substrate is finished to 0.3-3.0mum by centerless grinding or roller burnishing, and thereafter, moreover, by liquid honing, with respect to the surface of the aluminum tubular base body, a processing of 0.5-3.0mum surface roughness, and 5-50% surface area increase percentage is performed. For instance, in the case of working by a centerless grinding device, an object 3 to be ground is fed between a rotary grindstone 1 and a feed roller 2 for rotating in the same direction, and the object 3 to be ground is ground, while transferring it in the rotary shaft direction of the rotary grindstone 1 and the feed roller 2. In such a way, since a compression residual stress can be left on the tube outside surface by rolled working, a bend and roundness are improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aluminum tubular substrate for an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors having a photoconductive layer formed on an aluminum substrate are widely used. Particularly in the organic photoreceptor, a charge generation layer and a charge transport layer are laminated,
The so-called laminated type photoreceptor is put to practical use because of its high sensitivity and long life. Generally, such a photoconductive layer is provided on a conductive aluminum substrate, but if there are defects such as adhesion of foreign matter, dirt, and fine holes on the surface of the photoconductive layer, image defects caused by them will appear on the copy image. May appear in. By the way, when aluminum is usually used as a drum-shaped substrate, it is formed by processing it into an extruded tube, and then performing drawing, impact processing, ironing, etc., to obtain a drum with a predetermined wall thickness and outer mold size. be able to.

However, the surface of such an aluminum drum which is only non-grinded is rough and is not sufficient for use as a substrate for an electrophotographic photosensitive member. Therefore, the surface of the aluminum substrate is usually finished by mirror-finishing or the like as a subsequent process. For example, as shown in FIGS. 5 and 6, there are methods such as surface polishing with a grindstone and diamond bite cutting. However, such a cutting and polishing method requires chucking and fixing aluminum tubular substrates one by one to a cutting device and performing a surface treatment, which is troublesome in operation and requires time for setting. There is. Therefore, the manufacturing cost becomes high and it is not suitable for mass production.

Further, when it is attempted to finish the flatness or uneven surface within a predetermined range by cutting and polishing, fine inclusions such as metal powder of aluminum metal and bite residue (grinding residue) generated by cutting are cut objects. Providing a stable electrophotographic photosensitive member by being mixed between the objects to be cut, which reduces the workability of cutting and causes surface defects caused by them, which appear as streaks as image defects. It has the drawback that it cannot. Especially in the conventional method such as surface polishing by diamond bite cutting, due to the grooves roughened at regular intervals at regular intervals, a phase difference occurs in the reflected light on the aluminum substrate upper surface and the photosensitive layer surface during exposure. , That causes an interference fringe pattern. Such a phenomenon is caused by an electrophotographic method using coherent monochromatic light such as laser light as a light source.
Remarkably appears as an image defect. Especially during reversal development, black spots or streaks are generated, resulting in image defects.

[0005]

The problem to be solved by the present invention is to provide an aluminum substrate for an electrophotographic photosensitive member with a centering grinding process and then a suitable honing process as a surface treatment to obtain a laser beam or the like. It is an object of the present invention to provide an aluminum substrate for an electrophotographic photosensitive member which is excellent in the effect of preventing interference fringes for the photosensitive member using the coherent light as an exposure light source.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have diligently studied in order to eliminate the above-mentioned problems caused by the conventional surface shape and processing method for an aluminum substrate for an electrophotographic photoreceptor and achieve the object of the present invention. As a result, the aluminum tubular substrate having a predetermined surface roughness manufactured by extrusion and drawing is subjected to centerless grinding or roller burnishing to finish the surface roughness Rz of the aluminum tubular substrate to 0.3 to 3.0 μm. And then further subjecting the surface of the aluminum tubular substrate to a surface roughness Rz of 0.5 to 3.0 μm and a surface area increase rate of 5 to 50% by liquid honing. The present invention provides a method for manufacturing the same.

That is, according to the present invention, an aluminum tubular substrate having a surface roughness of 10 μm or less finished to a predetermined size by hot extrusion and then drawing is formed by a centerless grinding process or a roller burnishing process to form a groove in the circumferential direction of the aluminum substrate. Formed,
The groove was formed by surface grinding that does not have regularity in the twill shape of the concave and convex portions of the groove and the groove spacing, and after finishing to a surface roughness Rz of 0.3 to 3.0 μm, it was formed by the centerless grinding by liquid honing. Surface roughness Rz 0.5 to 3.0 μm and surface area increase rate 5 to 5 to the extent that irregular grooves do not disappear
By carrying out the surface treatment within the range of 0%, the object and problems of the present invention can be achieved.

The contents of the present invention will be described in detail below with reference to the drawings. The present invention uses an aluminum tubular substrate having a predetermined surface roughness as described above, and describes a case where the aluminum tubular substrate is processed by, for example, a centerless grinding device. It is sent between a rotary grindstone and a feed roller which rotates in the same direction, The cutting object is ground while being transferred in the rotation axis direction of the rotary grindstone and the feed roller.

As shown in FIG. 1, the centerless polishing apparatus sends an object 3 to be ground between a rotary grindstone 1 and a feed roller 2 which rotates in the same direction as the rotary grindstone 1, and the grindstone 3 is fed by a blade 4. It is supported and guided by guides 5, 6, 7, and 8, and is transferred while being ground in the rotational axis direction of the rotary grindstone 1 and the feed roller 2. The arrow indicates the direction of rotation.

FIG. 2 is a top view of the present grinding machine.
The same sign is shown. While the aluminum tubular substrate 3 of the object to be ground is sequentially sandwiched between the rotary grindstone 1 and the feed roller 2 from the direction A in the figure to the direction B, the object 3 itself is also rotated at random and in the direction of the axial direction B. To be ground while moving to.

According to this method, an unground aluminum tubular substrate prepared by non-grinding such as drawing can be flowed to the centerless cutting process of the next process on an automated line, and the number of grindings per hour can be reduced to the conventional one. Compared with the method, surface treatment can be performed with extremely high efficiency. Further, since the compressive residual stress can be left on the outer surface of the pipe by rolling, the bending and roundness are improved. Thus, the poor surface condition of the extruded aluminum tubular substrate surface can be corrected by using the method of the present invention to finish the desired surface condition.

Particularly, compared with the above-mentioned conventional example, since the operation of the object to be ground is rotated and transferred at random, the cutting marks caused thereby are aperiodically cut in the circumferential direction or the axial direction of the object to be ground. They may be crossed or crossed. Therefore, these processed grooves are important factors for eliminating the defect of image defect due to the interference fringes of the photoconductor, which has been a problem in the past.

Further, also in the roller burnishing machine, the same machining groove as the above-mentioned feature of the present invention is formed. FIG. 3 is an explanatory view of the roller burnishing device 9, in which the aluminum tubular substrate 3 to be ground is sequentially centered burnished (rolled) by a number of burnishing rollers 10 in a direction B from a direction A in FIG. Random groove marks are formed on the surface of the aluminum tubular substrate 3.
The arrow in the figure indicates the direction of rotation.

With regard to the shape of the groove to be applied to these objects to be ground, the processing conditions, the particle size of the grindstone, the roughness, the number of revolutions, the feed rate, etc. are appropriately adjusted to obtain the desired shape. To use a so-called centerless tube having an irregular and aperiodic groove shape on the surface as it is as an aluminum substrate of an electrophotographic photoconductor as it is, it causes defects such as black spots in terms of image quality and is stable. It is not possible to provide the electrophotographic photoconductor.

The reason is that the rotary grindstone 1 shown in FIG.
Since the aluminum tubular substrate ground in step 4 itself is a soft metal, fine irregularities are formed on the surface, as shown in FIG.
The aluminum metal burr 11 as shown in FIG. As shown in FIG. 4B, 3 is an aluminum substrate, 11 is an aluminum burr generated during centerless polishing, and 12 is a photosensitive layer. When a photosensitive layer is formed on the aluminum substrate, if aluminum burrs 11 are generated in the surface direction of the photosensitive layer,
Charges are injected from that portion toward the surface of the photosensitive layer, and as a result, the surface potential of the photosensitive member is canceled, and in the case of the reversal development method, black spots appear on the image, resulting in an image defect. As shown in Table-1, a photoconductor having an organic photoconductive layer having a thickness of 20 μm provided on a centerless-ground aluminum tubular substrate was prototyped, and the image quality of the photoconductor was evaluated by a laser printer of a one-component development cleaning system. went. At the same time, the aluminum tubular substrate bit-ground was also evaluated in the same manner.

[0016]

[Table 1]

As shown in Table 1, among the aluminum tubular substrate samples A to E subjected to centerless grinding, interference fringes occurred when the surface roughness was 0.3 or less, and black spots were observed when the surface roughness was 3.0 μm or more. Sample F is a non-cutting tube that is not subjected to centerless grinding, and is an aluminum tube that is a base material obtained by extrusion drawing. In this case, both black spot interference fringes were prominently seen. Sample G is an aluminum tubular substrate that has been uniformly roughened to a surface roughness of 0.5 μm by ordinary diamond cutting, and although black spots do not occur, interference fringes due to the aluminum surface being uniformly and regularly roughened. Seen. Therefore, the preferable surface roughness of the groove shape that constitutes the present invention is effective in the range of Rz 0.5 to 3.0 μm.

With respect to these points, FIGS. 7 and 8 compare the surface roughness of the conventional aluminum tubular substrate with that of the present invention. That is, FIG. 7 shows the surface roughness of an aluminum tubular substrate uniformly roughened to a surface roughness Rz of 0.5 μm by a conventional bite cutting, measured axially with a surface roughness meter. The length between a and b in the figure is 2.5 mm in the axial direction of the drum (magnification: 60 times). Figure 8
Shows the surface roughness of the aluminum tubular substrate formed by the centerless grinding process of the present invention measured by the same method as described above, and the surface roughness Rz is 0.5 μm (magnification: 60 times).

As can be seen by comparison, the groove roughness obtained by the conventional method shown in FIG. 7 is very flat and has a uniform and regular roughness. That is, since the groove spacing, pitch, etc. are regular, the roughness is also constant and regular. On the contrary, the groove roughness according to the method of the present invention in FIG. 8 has waviness of ridges and valleys and does not have a constant roughness. In other words, it has a very irregular property because the groove-like marks are discontinuous on the circumference due to centerless cutting, overlap with the adjacent groove, and the groove roughness of the partial part differs due to rolling pressure. Therefore, it is considered that the effect of preventing the interference fringe pattern is effective.

As can be seen from these results, in the conventional machining method such as cutting with a cutting tool, since the finished unevenness is regular, it causes interference fringes, but in the groove shape of the present invention, In particular, it has been proved to be an effective method for interference fringes. However, as described above, this is not sufficient when an image with high-quality light gradation is desired for an exposure light source of coherent light such as laser light, that is, to achieve the object of the present invention. However, the object of the present invention is achieved by roughening the aluminum surface processed as described above by a specific liquid honing process.

The honing process is a method of suspending a powdery abrasive in a liquid such as water and spraying it on the surface of an aluminum substrate at a high speed to roughen the surface into a concave shape as shown in FIG. In that case, the surface roughness can be controlled by the spraying pressure, speed, specific gravity and suspension concentration. It is desirable to use glass beads as the abrasive. The basic configuration of the apparatus includes a pump 13, an injection gun 14, an abrasive material 15, an air introduction pipe 16, a processing container 17, and an object to be polished 1.
It consists of eight.

A preferred shape of the honing process is roughening to such an extent that the groove does not disappear on the circumference formed by the centerless grinding, which is a standard of the honing process of the present invention. Therefore, the surface roughness of the honing treatment is Rz.
0.5 to 3.0 μm is suitable. Preferably 1 μm
The range of ˜2 μm is preferable. Further, as described above, the honing treatment is not performed on the surface of the aluminum tubular substrate roughened in the groove shape to such an extent that the grooves on the circumference of the aluminum tubular substrate are completely disappeared, and the effect of the present invention cannot be expected. Therefore, when compared in terms of area increase rate, the effect is maximized in the range of 5 to 50% due to the synergistic effect of the circumferential groove marks and honing.

[0023]

EXAMPLES The method of the present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention. The sample aluminum tubular substrate was formed by a centerless grinding process under desired conditions, and is an aluminum tubular substrate having a surface roughness Rz of 0.3 to 3.0 μm. The surface of this aluminum substrate was processed by a liquid honing method under various conditions, and an organic photosensitive layer having a thickness of 20 μm was provided on the aluminum substrate. In this way, the image quality of the obtained photoreceptor was evaluated by a laser beam printer using a one-component developing blade cleaning system.

[0024]

Example 1 A liquid honing apparatus was prepared by suspending 5 liters of a spherical abrasive (glass beads) in 29 liters of water.
This was carried out by spraying the aluminum tubular substrate to be polished with a compressed air pressure of 0.25 kg / cm ² by a pump. At that time, the spray gun was moved up and down at 30 cm / sec, while the aluminum tubular substrate was rotated at 8 rpm. Processing time 15sec, 30sec, 45se
By changing the time from c to 60 seconds, an aluminum tubular substrate having irregular groove-shaped irregularities before processing is processed, and thereby the surface area per unit area is increased. The increase rate of this surface area is shown in Table-2. Further, Table 3 shows the evaluation results of the image quality of the photoconductor in which the photosensitive layer is provided on the honed aluminum tubular substrate, in the form corresponding to the conditions of Table 2.

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

Example 2 The compressed air pressure in Example 1 was 0.5 kg.
/ Cm ² , and the processing time is 15 sec, 30 sec, 4
By changing the treatment time from 5 sec to 60 sec, the surface area increase rate was obtained. In addition, Table 3 shows the image evaluation results.

[0028]

[Embodiment 3] The compressed air pressure in Embodiment 1 is 1.0 kg.
/ Cm ² , and the processing time is 15 sec, 30 sec, 4
The rate of increase in the surface area was obtained by changing the treatment time to 5 seconds. In addition, Table 3 shows the image evaluation results.

[0029]

[Embodiment 4] The compressed air pressure in Embodiment 1 is 2.0 kg.
/ Cm ² , and the processing time is 15 sec, 30 sec, 4
By changing the treatment time from 5 sec to 60 sec, the surface area increase rate was obtained. In addition, Table 3 shows the image evaluation results.

[0030]

[Embodiment 5] The compressed air pressure in Embodiment 1 is 3.0 kg.
/ Cm ² , and the processing time is 15 sec, 30 sec, 4
The rate of increase in the surface area was obtained by changing the treatment time to 5 seconds. In addition, Table 3 shows the image evaluation results.

[0031]

[Comparative Example 1] Similar to the example, the particle diameter of the glass beads as the abrasive was changed to 50 μm and the compressed air pressure was 2.0 kg / c.
m ² , processing time is 15 sec, 30 sec, 45 s
By changing the ec to 60 sec, the surface area increase rate was obtained. In addition, Table 3 shows the image evaluation results.

[0032]

[Comparative Example 2] As in the example, the particle diameter of the glass beads as the abrasive was changed to 100 μm, and the compressed air pressure was 2.0 kg /.
cm ² , processing time is 15 sec, 30 sec, 45
The rate of increase in the surface area was obtained by changing the treatment time between sec and 60 sec. In addition, Table 3 shows the image evaluation results.

[0033]

[Comparative Example 3] The increase rate of the surface area was obtained in the extruded drawn tube which was not subjected to the centerless grinding (the same condition as in Example 4). In addition, Table 3 shows the image evaluation results.

[0034]

Comparative Example 4 The surface area increase rate was obtained under the same conditions as in Example 4 on an aluminum tubular substrate roughened to a surface roughness of 2.0 μm by the conventional cutting tool cutting. In addition, Table 3 shows the image evaluation results. From Table-2 and Table-3, when the particle size of the glass beads of the abrasive is 20 μm, the compressed air pressure is 0.25 kg.
/ Sec ² and 0.5kg / cm ² processing time 45sec
Until then, black spots and interference fringes caused by burrs were generated. However, the processing time for compressed air pressure 0.5 kg / cm ² is 60 sec.
c and 1 kg / cm ² , 2 kg / cm ² were good with no black spots.

However, fog occurs on the image when the compressed air pressure is 3.0 kg / cm ² . Also compressed air pressure 2.0 kg / c
Even with m ^2, if the particle size of the glass beads becomes 50 μm, fogging occurs for a processing time of 45 seconds or more. As shown in Table 2, it can be seen that the surface area per unit area after liquid honing is 54.3% in the case where fog starts to occur. Compressed air pressure 2.0kg / cm ² , processing time 60se
The surface area increase rate when processed with c is 50%, and the surface area increase rate when processed with compressed air pressure of 3.0 kg / cm ² and processing time of 15 sec is 54.3%. The image quality of the former is good and that of the latter causes fog on the image.
Therefore, if the surface area increase rate is 4.8% or less, burr is not completely taken care of and black spots occur, so the effective range when liquid honing is 5% or more and 50% or more.
By the following treatment, an electrophotographic photosensitive member having stable image quality can be obtained.

Furthermore, a significant difference was observed in the surface roughness as the surface area was increased by the honing process.
Particularly, in the vicinity of the boundary value of the surface area increase rate of 5%, the compressed air pressure was 0.5 kg / cm ² , and the surface roughness was 0.43 μm at the processing time of 45 sec and 0.5 μm at the time of 10 sec. Furthermore, near the boundary value of the surface area increase rate of 50%,
When the compressed air pressure is 2.0 kg / cm ² and the processing time is 60 sec, the surface roughness is 2.8 μm, and the compressed air pressure is 3.0 kg.
/ Cm ² and processing time 15 sec, surface roughness is 3.1μ
It was m.

As described above, it can be seen that the surface roughness after the honing process is small as the surface area increases with a small increase rate, and the surface roughness is large with a large increase rate. From the above results, the surface roughness of the centerless tubular substrate of the present invention in the honing process is 0.5 μm.
The range of up to 3.0 μm is effective.

[0038]

The aluminum substrate for an electrophotographic photoreceptor according to the present invention obtained as described above is centerless ground on a non-cutting aluminum tubular substrate which cannot be used as it is because of many stains, protrusions, scratches, dents and the like on its surface. These defects can be removed by the treatment and liquid honing treatment, and the surface treatment can be performed with high efficiency, which is most suitable for industrialization. The present invention can obtain excellent image quality without interference fringes, especially when coherent light such as laser light is used.

[Brief description of drawings]

FIG. 1 is a front view of a centerless grinding apparatus of the present invention.

FIG. 2 is a top view of the centerless polishing apparatus of the present invention.

FIG. 3 is an explanatory view of a roller burnishing processing device of the present invention.

FIG. 4A is a sectional view showing a burr on the aluminum surface.
FIG. 7B is a diagram illustrating the mechanism of black spot generation.

FIG. 5 is a front view showing an example of a conventional grindstone polishing apparatus.

FIG. 6 is a front view showing an example of a conventional diamond bite cutting device.

FIG. 7: Surface roughness Rz 0.5 μ obtained by conventional bite cutting
The surface roughness of the aluminum tube uniformly roughened to m was measured in the axial direction by a surface roughness meter (magnification: 20,000).
0 times).

FIG. 8 is a diagram showing the surface roughness of an aluminum tubular substrate formed by the centerless grinding process of the present invention as measured by the same method as described above (magnification: 20,000 times).

FIG. 9 is a front view of the liquid honing processing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 rotating grindstone 2 feed roller 3 object to be ground (aluminum tubular substrate) 4 blade 5-8 guide 9 roller burnishing machine 10 burnishing roller 11 aluminum burr 12 photosensitive layer 13 pump 14 injection gun 15 abrasive material 16 air introduction pipe 17 processing container 18 Object to be ground (aluminum tubular substrate)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazu Yamada 19-27, Tokoji Temple, Kofu City, Yamanashi Prefecture

Claims (1)

[Claims] 1. A surface roughness Rz of an aluminum tubular substrate by centerless grinding or roller burnishing.
Of 0.3 to 3.0 μm, and further subjected to liquid honing so that the surface roughness Rz of the surface of the aluminum tubular substrate is as large as the centerless grinding or roller burnishing groove does not disappear. 5-3.0μ
m, and a surface area increasing rate of 5 to 50% are applied to the aluminum tubular substrate for an electrophotographic photosensitive member.