JPH02291563A - Production of optical drum - Google Patents

Abstract

PURPOSE:To provide the optical drum having precise shape accuracy by executing an inside surface ironing in a container having a desired inside surface characteristic and shape and transferring the inside surface characteristic and shape of the container to the outside surface of a cylindrical stock simultaneously with the thickness reduction working of the stock. CONSTITUTION:A cylindrical ironing device is used and the inside surface 4 of the cylindrical container 2 is finished to the surface characteristic and shape and size corresponding to the outside surface characteristic of the optical drum to be produced. The prescribed metallic cylindrical stock 6 is inserted into the container 2 and the inside surface of this metallic cylindrical stock 6 is subjected to the ironing. the metallic cylindrical stock 6 is subjected to a fairly large plastic deformation and internal pressure in the thickness direction thereof by this ironing and is press fitted to the inside surface of the container 2, by which the surface characteristic and shape of the inside surface 4 of the container 2 are exactly transferred to the outside surface of the metallic cylindrical stock 6. The outside surface characteristic and shape of the cylindrical optical drum are exactly obtd. in this way and the quality thereof is stabilized.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a method for manufacturing an optical drum, and in particular, to advantageously manufactures a cylindrical optical drum having a desired precise outer surface and shape created by internal ironing. It's about how to do it.

(Background Art) Various processing methods have been studied and put into practical use in order to create the desired outer surface properties and shape of a cylindrical optical drum. In order to make the outer surface of the photosensitive drum mirror-like, in addition to the cutting method, which simply involves cutting a predetermined pipe (cylindrical metal material), a predetermined plate material (metal material) is drawn and formed, and then ironed. DI method, which processes to thin the wall and finally performs cutting,
After extruding a specified billet into a bottomed cylindrical material, ironing is performed, and finally cutting is performed II.
E method is known and ironing process of specified extrusion pipe is carried out.
Also known are the l method and the ED method in which an extruded pipe is drawn.

However, all of these processing methods have some problems inherent in them, and it is difficult to achieve a high degree of mirror finish on the mirror-like outer surface, making it difficult to obtain a high-quality photosensitive drum. It was difficult. For example, with conventional cutting methods, there are problems such as long cutting time, inevitably low productivity, and high cutting costs.In addition, as the thickness of the material becomes thinner, the dimensional accuracy of the shape deteriorates. There are problems such as: In addition, in the DI method, II method, and EI method, ironing is applied to the outer surface of the cylindrical material in order to reduce the wall thickness. was damaged, making it difficult to form a high-quality mirror surface.Furthermore, even with the ED method,
There was a limit to how much the mirror surface could be improved.

On the other hand, the present inventors previously demonstrated at the 38th Joint Plastic Working Conference (October 6-8, 1987) that by ironing a strip, the back surface of the strip was brought into contact with the back surface of the strip. Although it has been shown that the condition of the tool surface can be transferred, in such strip ironing process, the wall thickness tends to change in the width direction of the strip, in other words, in the direction orthogonal to the ironing direction, and As a result, distortion and non-uniform surface properties of the strip tend to occur.

As a result of further research into the creation of a precision surface by the previously proposed tool surface transfer, the present inventors found that by applying internal ironing to a cylindrical metal material, the material could be made thinner while at the same time. , both the surface texture and shape of the inner surface of the container, which is the ironing tool, are accurately transferred to the outer surface, and unlike the case of flat ironing, which is a flat ironing process, the ironing process is carried out on the part perpendicular to the ironing direction, i.e. There is no change in the surface texture in the circumferential direction, and therefore it is possible to obtain an ironed product having an outer surface texture and shape that accurately corresponds to the surface texture and shape of the inner surface of the container in the axial and circumferential directions. They have discovered that this can be advantageously applied to the production of optical drums such as the light-absorbing drum of the copying machine mentioned above.

(Problem to be Solved) The present invention was completed under the above circumstances, and the object to be solved is to realize the outer surface properties and shape of a cylindrical optical drum with extreme accuracy, Another object of the present invention is to stabilize the quality thereof, and furthermore, to manufacture such a cylindrical optical drum having excellent outer surface properties and precise dimensions with high productivity, and to reduce the cost thereof.

(Solution Means) In order to solve this problem, the present invention provides an inner surface with a surface texture corresponding to the outer surface texture when manufacturing a cylindrical optical drum having a desired outer surface texture and shape. Using a container having a shape of The surface texture and shape of the inner surface of the container are transferred to the outer surface of the metal cylindrical material.

Note that the optical drum referred to here is a cylindrical body having a cross-sectional profile such as a circle or a polygon, and its outer surface is (
a) Ultra-precise mirror surfaces such as photosensitive drums for copying machines,
(b) A surface having a specific surface roughness, minute irregularities, and surface pattern.

(Specific Structure/Example) In short, in the present invention, a cylindrical ironing device as schematically shown in FIG. It is finished with a surface texture (for example, a mirror-like inner surface) and a shape and size that correspond to the outer surface texture of the drum. And this container 2
A predetermined metal cylindrical material 6 is inserted into the inner tag of the material 6, and the portion of the material 6 protruding from the end of the container 2 is held in place by gripping or other means. The punch 8 is pressed, and the inner surface of the metal cylindrical material 6 is ironed.

Through such internal ironing process, the metal cylindrical material 6 is subjected to considerably large plastic deformation and internal pressure in the direction of its wall thickness, and is crimped to the inner surface of the container, thereby allowing the metal cylindrical material 6 to be thinned. At the same time, container 2
The surface texture and shape of the inner surface 4 of the metal cylindrical material 6 will be accurately transferred to the outer surface of the metal cylindrical material 6, thereby making it possible to create a desired precision surface on the outer surface of the metal cylindrical material 6. At the same time, it became possible to mold precise shapes. Moreover, in the container 2, the metal cylindrical material 6 is plastically deformed as a whole while maintaining balance in the circumferential direction, so uniform ironing can be performed not only in the axial direction but also in the circumferential direction. This makes it possible to obtain a precise transfer surface that is uniform even in the circumferential direction.

In this way, the present invention applies ironing to the inner surface of a cylindrical metal material, unlike the conventional ironing of the outer surface. It will be used in the same way. Of course, it is desirable to apply a good lubricant to the inner surface of the metal cylindrical material 6 to be ironed according to the present invention in order to reduce the force required for ironing, but it is preferable to apply a good lubricant to the outer surface without using lubricant. Implementing this will improve the transfer accuracy. However, in order to avoid problems such as adhesion between the inner surface 4 of the container 2 and the outer surface of the metal cylindrical blank 6, a suitable lubricant, particularly a low viscosity lubricant, typically 100 centistokes (2
0°C) or less, preferably 50 centistokes (20
°C) It is desirable to use the following lubricants. Even if a lubricant exists between the inner surface 4 of the container 2 and the outer surface of the metal cylindrical material 6, the inner surface squeezing action effectively reduces the occurrence of oil pits caused by such lubricant. This can advantageously contribute to the creation of an accurate transfer surface.

In addition, in the inner surface ironing method according to the present invention, a predetermined metal cylindrical material that provides the desired cylindrical optical drum, for example, a photosensitive drum of a copying machine, is made of pure Al;A;
ff-Mn system, AI! ．． - By using an aluminum base tube such as A1 alloy such as Mg type and ironing it at a desired ironing rate, the wall thickness can be reduced to the desired thickness of the optical drum. As for the straining rate, a straining rate of 5% or more, preferably about 10 to 50% is advantageously employed. As the rubbing rate increases, the transferability of the inner surface of the container can be further improved.

In this way, according to the method of the present invention, the inner surface of the container is
Because it is accurately transferred to the outer surface of a metal cylindrical material, it can be used to create extremely precise mirror surfaces such as the photosensitive drum of a copying machine, surfaces with uniform surface roughness and reflectance, It has become possible to create a surface with uniform fine irregularities similar to that of a laser disk on the outer surface of a metal cylindrical material. Of course, in order to obtain the desired outer surface quality of such a metal cylindrical material, the inner surface of the container must be finished to a corresponding surface quality.
It goes without saying.

By the way, the excellent features of the method of the present invention as described above are also clear from the following discussion.

First, a strip made of pure aluminum (AIIOO) was ironed using paraffin mineral oil [viscosity: 1] as a lubricant.
B. 2 centistokes (20'C)) was used at an ironing rate of 15.3%, and the plate thickness was 0.39 m.
An ironed plate having a width of 10 mm was obtained. Note that the roughness of the transfer surface of the tool that supports the strip to be ironed and against which the strip is pressed is Rmax'=O. lam
Met. A part of the transfer surface of the obtained ironed board is shown in FIG. was getting thicker. Further, the results of measuring the surface roughness of such an ironed plate are shown in FIG. 2(b).

In the ironing process of such a flat plate, which is a flat transfer, uneven surface texture tends to appear as shown in the figure, and as is clear from FIGS.
Although it is a mirror surface with Rmax=0.1μm in area B, Rmax=0.6μm in area B, and Rmax=0.6μm in area C.
The surface is relatively rough with a maximum of about 1.2 μm, and in particular, regions B and C are observed as white and cloudy surfaces to the naked eye. When the surfaces of areas B and C were observed in detail with an optical microscope, countless tiny oil pits were observed in the entire area, indicating that the lubrication state of the transfer surface during processing was quite uneven in the width direction L. It is inferred that In most cases, such surface properties appear when the undeformed part of the strip bends (distorts) in the strip width direction during processing, and when the strip bends, material-iron tool contact occurs. It is thought that the surface pressure and lubrication state become non-uniform, and such non-uniform surface properties appear.

In contrast, according to the present invention, pure aluminum (AI
paraffinic mineral oil (viscosity: 1B.IOO) as a lubricant. 2 centistokes (20°C)) at an ironing rate of 31%, the inner diameter was as shown in Fig. 3(a):
An ironed cylinder having a diameter of 40 mm and a wall thickness of 20.77 mm was obtained. The roughness of the transfer surface on the inner surface of the container is Rmax 0
．． It was 25 μm. Then, the surface roughness of each part in the circumferential direction of the ironing cylinder shown in FIG. 3(a) was measured, and the results are shown in FIG. 3(b).

As is clear from FIGS. 3(a) and (b), when the inner surface of the cylinder is ironed according to the present invention,
Since the product shape is axially symmetrical, there is almost no risk of uneven lubrication and hence uneven surface texture as in the case of the above-mentioned plane transfer. As is clear, the surface roughness in the circumferential direction of the ironing cylinder is approximately uniform in the circumferential direction, even though the circumferential length is quite long, about 12 On+m. It was confirmed that precision surface cylinders can be stably manufactured. In addition, in the case of a cylindrical body, since the material is closed in the circumferential direction, a relatively large compressive stress in the circumferential direction is likely to occur, and therefore a large hydrostatic stress can be applied to the material as internal pressure. It is considered to be advantageous in achieving excellent effects and effects in the field.

In addition, deep drawing processing was performed using an aluminum blank plate: A1100-0 material, outer diameter: 40 mmφ, wall thickness: 0.
7 1 mm, external surface properties: Rmax = 0.6 6
A cylindrical body having a diameter of μm was produced, and then the inner surface of the cylindrical body was subjected to ironing according to the present invention. In addition, the surface texture of the inner surface of the container is Ra = 0.03 μm, Rmax
= 0. The angle (α) formed by the tapered surface of the tip of the punch is 28 degrees, and the ironing speed is 0.
5+nm/s, Lz plan: 11%, 20%, 31%,
Room temperature: 20±2°C, lubricant: paraffinic mineral oil (viscosity: 1B.2 centistokes at 20'c).

Then, the surface roughness of the outer surface of each of the ironed products (cylinders) having different ironing rates was measured, and the results are shown in Table 1 below.

Table 1 As is clear from the results in Table 1, the inner surface ironing process according to the present invention yields an ironed product having an outer surface corresponding to the inner surface of the container, and in such ironing process, By increasing the ironing rate, the transferability can be further advantageously improved.

In carrying out the present invention, an ordinary ironing device is used, and a punch is press-fitted to perform a prescribed ironing process between a specified metal cylindrical material and the inner surface of a container. However, once the inner surface is ironed, the metal material (product) will be brought into close contact with the inner surface of the container, so it is not recommended to forcefully pull out such a metal material from the container as it is. This should be avoided as it may damage the outer surface of ironed products.

For this reason, in order to take out the ironed product from inside the container, in addition to dividing the container to the extent that it does not cause any problem, we also use the difference in thermal expansion between the container and the ironed product.
There is a method to further shrink the product by cooling and then take it out, a method in which the container has a double-tube structure and is banked up using hydraulic pressure, and after processing, the hydraulic pressure is released to make it easier to take out the product. In this method, various methods are adopted as appropriate, such as a method in which a double-tube container with a Taber fitting structure is used, and the inner container is pulled out depending on the Taber shape, and the product is then taken out from there.

In addition, when carrying out the present invention, various known conditions or structures may be adopted, added to, or substituted based on the knowledge of those skilled in the art, without departing from the spirit of the present invention. It should be understood that all of these embodiments fall within the scope of the present invention.

(Effects of the Invention) As is clear from the above description, the present invention is capable of thinning the material and simultaneously reducing the thickness of the target surface by ironing the inner surface in a container having the desired inner surface properties and shape. This method transfers the inner surface properties and shape of the container to the outer surface of the cylindrical material, creating a uniform and extremely precise surface, and at the same time molding a precise shape, resulting in higher quality than conventional methods. As a result, it became possible to obtain an optical drum with surface texture and precise shape accuracy.
Furthermore, it has become possible to easily obtain an optical drum that exhibits an outer surface texture that corresponds to the inner surface texture or pattern of the container.

Furthermore, according to the method of the present invention, the desired optical drum can be obtained by simply ironing.
Compared to conventional cutting methods, machining time can be significantly shortened, thereby improving productivity and advantageously reducing costs.
The final cutting process, such as that required by the method, is now completely unnecessary.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing one form of internal ironing according to the present invention, FIG. FIG. 3(b) is a graph showing the measurement results of the surface roughness in the width direction of such an ironed strip, and FIG. FIG. 3(b) is a graph showing the measurement results of the surface roughness in the circumferential direction of a cylindrical body subjected to such an internal ironing process. 2: Container 6: Metal cylindrical material 4: Inner surface 8: Ponchim Figure 1 Kawai Mododa Kuniaki Kaifuji Masami Sumitomo Light Metal Industries Ltd. Figure 2 (a) (b) Figure 3 (a) (0@) (b) (0@) (90°) (180°) (270@) (360”)

Claims (1)

[Claims] A method for manufacturing a cylindrical optical drum having a desired outer surface texture and shape accuracy, comprising: a container having an inner surface having a surface texture corresponding to the outer surface texture and a required inner shape precision; A predetermined metal cylindrical material is inserted into the container, and the inner surface of the metal cylindrical material is ironed to apply macroscopic plastic deformation and internal pressure to change the surface texture of the inner surface of the container. A method for manufacturing an optical drum, which comprises transferring the image onto the outer surface of the metal cylindrical material.