JP2642356B2 - Method of manufacturing photoconductor drum - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accurately and thinly manufacturing an aluminum drawing tube as a photosensitive drum base of an electrophotographic copying machine.

2. Related Art and Problems The photoreceptor used in the electrophotographic copying machine is a photoreceptor drum,
The photoconductor is composed of a photoconductive layer formed on the photoconductor drum, and the photoconductor is assembled into a copying machine in a form in which a flange is press-fitted and fixed.

The photosensitive drum is a process of hot extruding a billet obtained by cutting an aluminum ingot made of aluminum or an aluminum alloy into an appropriate size to form an aluminum tube (hereinafter, the aluminum tube obtained in this process is referred to as a “hot extruded tube”). )), A drawn tube (hereinafter, referred to as a “drawn tube”) manufactured through a step of drawing the hot extruded tube at room temperature is obtained as an aluminum substrate cut into a desired size, and usually further obtained by a predetermined process. It is cut to the shape and dimensions.

However, since the hot extruded pipe is cooled without aggressive cooling control means, the cooling becomes non-uniform, and residual stress is accumulated non-uniformly inside the hot extruded pipe. As a result, when the drawing tube is cut to a predetermined size after each of the hot extrusion and drawing steps to manufacture the photosensitive drum, the residual stress is released and the photosensitive drum is distorted. Therefore, it is difficult to obtain a photosensitive drum with high roundness and without variation.

With a photoreceptor composed of a photoreceptor drum having such a poor roundness, development is not performed uniformly, and an image of poor quality with image density unevenness is formed.

Recently, it has been desired to reduce the thickness of the aluminum photosensitive drum from the viewpoints of further resource saving and cost reduction. However, the thinner the thickness, the more the above-mentioned problem becomes more serious.

In addition, a flange is press-fitted and fixed to the photoconductor drum to fix the photoconductor to the copying machine.In this case, if there is distortion and dimensional variation in the photoconductor drum, the inner surface of the photoconductor drum is cut. It is necessary to adjust the inner diameter (hereinafter referred to as "inner diameter cutting"), and the photoreceptor drum must have sufficient mechanical strength to withstand press-fitting and fixing of the flange.

Furthermore, since the photosensitive layer is formed on the photoreceptor drum after the outer surface of the photoreceptor drum is usually cut into a predetermined shape (hereinafter referred to as "outside diameter cutting"), uneven residual stress is present. Then, at the time of the cutting processing or the formation of the photosensitive layer, distortion of the photosensitive drum occurs. Also at this time, the photoreceptor drum needs to have a mechanical strength that can withstand the force applied at the time of cutting or forming the photosensitive layer.

However, cutting the inner diameter or outer diameter of a photosensitive drum having distortion or dimensional variation is effective for a photosensitive drum having a certain thickness, but is not so effective in improving accuracy. After all, an image having uneven density is formed, and a high-quality image cannot be obtained. With thinner photoreceptor drums, the tendency becomes even more pronounced, making such photoreceptor drums unusable.

A technique for preventing distortion occurring during the formation of a photosensitive layer is described in, for example, JP-A-56-74265. In the above technique, an aluminum substrate is annealed to release internal stress, then cut into a predetermined size and shape, and a photosensitive layer is deposited on the surface to prevent the occurrence of distortion due to heat at that time.

However, in the above technique, the roundness of the photosensitive drum is achieved by cutting the outer diameter, and it is difficult to reduce the thickness by reducing the thickness and the thickness, and furthermore, the inner diameter needs to be cut.

Problems to be Solved by the Invention The present invention has been made in view of the above circumstances, and has as its object the absence of non-uniformly distributed residual stress, high roundness and high roundness. It is an object of the present invention to provide a method for manufacturing a thin photosensitive drum having dimensional accuracy.

Another object of the present invention is to provide a method for manufacturing a photosensitive drum that can achieve a further cost reduction in addition to the above objects.

A further object of the present invention is to produce a photosensitive drum which does not require cutting of the inner diameter of the photosensitive drum and which has a sufficient mechanical strength to withstand the photosensitive layer forming step or the press-fitting and fixing of the flange, though it is thin. The aim is to provide a method.

Means for Solving the Problems That is, the present invention relates to a method for manufacturing a photoreceptor drum, in which a drawn tube made of aluminum or an aluminum alloy is further drawn after annealing, and is not subjected to further annealing after the drawing. The present invention relates to a method for manufacturing a photosensitive drum.

In the present invention, a drawn tube manufactured by drawing a hot extruded tube once according to a conventional method can be used. Such hot extruded tubes typically have non-uniform residual stresses therein, but the present invention first releases such residual stresses by annealing. Release of the residual stress is effective in suppressing the occurrence of distortion of the pipe. Although the pipe strength is reduced by the release of the residual stress due to the annealing, the predetermined strength can be achieved by performing cold drawing again. The above effects are somewhat different depending on the type of aluminum alloy. For example, a heat-treated alloy (for example, aluminum alloy A6063) is more effective than a non-heat-treated alloy (for example, aluminum alloy A3003).

Annealing is performed by heating the drawn tube to a predetermined temperature and gradually cooling it.

The annealing temperature is higher than the recrystallization temperature of the aluminum or aluminum alloy constituting the drawn tube and lower than the melting point, preferably 320 to 450 ° C., depending on the type of the aluminum alloy, and more preferably 400 to 420 ° C. It is. If the heating temperature is lower than the recrystallization temperature, the release of residual stress is incomplete, and if it is higher than 450 ° C, the crystal grains become coarse,
Adverse effects on quality occur.

As the cooling condition, it is preferable to cool at a rate as low as possible up to a temperature lower than the recrystallization temperature, preferably up to 260 ° C. or lower. If the cooling rate is 28 ° C. per hour in terms of production efficiency and quality, the effects of the present invention are not hindered. When the cooling rate is higher than 28 ° C./hour, a solution treatment effect occurs, and thermal stress remains. If the cooling control is released at a temperature higher than the recrystallization temperature, the release of the residual stress becomes incomplete.

Next, the drawn tube subjected to the annealing treatment is stretched to a predetermined size and thickness in a further drawing step and then cut to obtain a photosensitive drum.

This further drawing may be performed by a known drawing method.However, according to the method of the present invention, a tube having substantially no non-uniform residual stress in the drawn tube can be obtained. When it is stretched and cut, no distortion or deformation occurs. Therefore, a photosensitive drum having a high roundness and no variation can be efficiently manufactured.

A photoreceptor drum usually has an outer diameter of 40 to 80 mm and a thickness of 2
An aluminum tube of 4 mm is used, but according to the present invention, it can be stretched thinly to a thickness of 1-1.5 mm.

In addition, the photoreceptor drum obtained by cutting does not have to worry about tube deformation and distortion due to release of non-uniform residual stress, and it already has predetermined dimensions and roundness. There is no. Outer diameter cutting may be performed as required to obtain a predetermined surface roughness.

The obtained photoreceptor drum has improved tensile strength compared to a tube obtained only by annealing, and even if the wall thickness is thin,
It has sufficient strength to withstand the force applied during the press-fitting of the flange and the formation of the photosensitive layer.

The photosensitive drum obtained as described above is provided with a photosensitive layer thereon, and is incorporated and used in an electronic copying apparatus or the like in a state in which a flange is press-fitted and fixed.

 Hereinafter, the present invention will be described with reference to examples.

Example 1 Using an aluminum alloy A6063, hot extrusion was performed at a temperature of 400 to 500 ° C. to form a hot extruded tube (98 mm in outer diameter, 90 mm in inner diameter).
mm), the tube was drawn at room temperature to produce a drawn tube (outer diameter 90 mm, inner diameter 85 mm). The drawn tube was treated by the following three methods A, B, and C, and then cut to produce 50 aluminum tubes (outer diameter 80.5 mm, inner diameter 78 mm, wall thickness 1.25 mm, length 340 mm).

The inner diameter of each of the obtained aluminum tubes was measured at three arbitrary positions at three positions to determine the standard deviation.

Further, the tensile strength of each aluminum pipe according to JISZ2241 was measured, and the average value was obtained.

 Table 1 shows the above results.

Method A (annealing treatment) After the drawn tube (outer diameter 90 mm, inner diameter 85 mm) is subjected to an annealing treatment in which it is heated to 410 ° C and cooled to 260 ° C at a rate of 25 ° C per hour, the second drawing is performed at room temperature. Done, outer diameter 8
It was elongated to 0.5 mm and 78 mm in inner diameter. Note that a furnace of a batch furnace type was used for annealing.

Method B (Tempering) A drawn tube (outside diameter 90 mm, inside diameter 85 mm) is drawn a second time at room temperature, stretched to 80.5 mm in outside diameter and 78 mm in inside diameter, and subjected to tempering treatment at 250 ° C. for 1 hour. did.

Method C (untreated) A drawn tube (outside diameter 90 mm, inside diameter 85 mm) was drawn a second time at room temperature and stretched to have an outside diameter of 80.5 mm and an inside diameter of 78 mm.

Table 1 shows that the aluminum pipe obtained by the method A subjected to the annealing treatment has a 50% or more variation in the inner diameter than the aluminum pipe obtained by the method B or the method C, and has good roundness and dimensional variation. Is small.

With respect to the tensile strength, the aluminum pipe obtained by the method A shows a slight decrease compared to the aluminum pipe obtained by the method C. However, after the annealing in the method A, the tensile strength when the drawing step was not performed (about 8Kg / mm ² ), which was considerably higher.

Example 2 A photoconductor was manufactured using photoconductor drums having different roundnesses, and the relationship with density unevenness (ID unevenness) was observed.

The photoreceptor drum used had a circularity of 12 μm, 20 μm, 68 μm, and 94 μm.

On the photoreceptor drum, a charge generation layer composed of a bisazo pigment and a binder resin and a charge transport layer composed of a hydrazone and a binder resin were laminated and formed.

On the other hand, as an original image for displaying a reference image for image density measurement, an A3 original paper in which black squares of 1 cm on a side as shown in FIG. did. Here, a row composed of seven blacks in the uppermost row of the base paper is referred to as a first row, a second row, and so on, and a lowermost row is referred to as a tenth row.

Using this base paper and the above photoreceptor, continuous copying of 20 sheets was performed. A serial number is assigned to each line of the obtained 20 sheets of copy paper, One of the seven black square columns in the first row of the first sheet was randomly picked, and the image density of the black square in the same column in each row was measured. The results are shown in a graph showing the number of rows on the horizontal axis and the image density (ID) on the vertical axis. A Macbeth reflection densitometer was used for image density measurement.

2 to 5 show the circularity of 12 μm, 20 μm and 68, respectively.
The results when the photoconductor drums of μm and 94 μm are used are shown. It can be understood that the lower the roundness, the greater the variation in image density.

According to the present invention, it is possible to manufacture a photosensitive drum having a high roundness without distortion or deformation, with a thinness and a non-uniformity which have not been achieved conventionally.

The use of a photoconductor composed of a photoconductor drum having a high roundness obtained according to the present invention enables uniform development,
A high-quality image without unevenness in image density is formed.
Therefore, the present invention can reduce the thickness of the photosensitive drum without deteriorating the image quality, and is effective for cost reduction and resource saving.

Furthermore, the obtained photoreceptor drum has improved tensile strength as compared with the drawn tube after annealing, and can sufficiently withstand the force applied during the press-fitting of the flange, the formation of the photosensitive layer, etc., even if the thickness is thin. Has strength.

[Brief description of the drawings]

FIG. 1 is a view showing an original image representing a reference image for measuring image density. 2 to 5 are diagrams showing variations in image density.

Claims (1)

(57) [Claims] 1. A method of manufacturing a photosensitive drum, comprising: drawing a tube made of aluminum or an aluminum alloy after annealing and further drawing the tube; and performing no further annealing after the drawing. Production method.