JPH0670270B2 - Method for manufacturing aluminum alloy substrate for amorphous silicon photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a member used in an electrophotographic copying machine or a laser printer, and is photoconductive amorphous Si (hereinafter abbreviated as a-Si). The present invention relates to a method for manufacturing an aluminum alloy substrate used for forming a film on a photoreceptor.

(Prior Art) In an electrophotographic copying machine or a laser printer, a light beam emitted from a light source is applied to a photoconductive pre-charged photoconductor to form an electrostatic latent image, and a colored powder is formed on the photoconductor. A method is used in which the powder is transferred to a copying material after the body is attached.

As a photoreceptor having such properties, a vapor deposited film of Se is widely used, but in recent years, high image characteristics and durability have been demanded, and a film of a-Si is required to satisfy such properties. Has come to be used. This a-Si
To form a film, a vacuum deposition method utilizing a discharge phenomenon such as a plasma CVD method, a glow discharge method, or a sputtering method can be applied. In order to keep the photosensitive characteristics of the film in a good state, the above Se vapor deposition Thinner than the film, eg 30μm or less Normally
Since it is used with a thickness of ~ 20 μm, the surface of the substrate on which this a-Si film is formed needs to have a smoother finished surface than conventional ones. Therefore, a high purity (99.85 wt% or more) aluminum substrate is required. Gold moth is used. This is because the presence of elements such as Fe and Si as impurities in the aluminum ingot,
Coarse intermetallic compound particles such as high hardness Al ₃ Fe, AlFeSi, Mg ₂ Si, etc. are formed, resulting in cutting scratches (hereinafter referred to as scratches) when precision cutting the surface of the substrate, and this part forms a film. It has been considered that the non-uniformity of the a-Si film sometimes causes uneven adhesion when the colored powder adheres, and causes image defects such as color loss and black spots when transferred to a copying material. Further, it is considered that the image defects such as color loss are caused not only by the scratches but also by the gas holes. Therefore, when the aluminum alloy is melted, the substrate is manufactured using a material sufficiently degassed. The method of doing is also proposed.

By the way, this substrate is required not only to have corrosion resistance but also to have strength characteristics from the viewpoints of handleability and durability. Therefore, it is difficult to form Al and high hardness intermetallic compound particles, and strength characteristics are imparted by plastic working. Easy to do Mg
Al-Mg based alloys containing about 4 wt% of Al and other elements such as Mn, Cr, Zn, Ti, B and Cu are added as desired.

Therefore, such an Al-Mg alloy substrate has a purity of 9
A high-purity aluminum ingot of 9.85 wt% or more is used to sufficiently degas an Al-Mg alloy with the desired composition, melt it, cast it, mold it, and then cut it with a cutting tool such as a natural diamond tool. It is made by precision cutting. The cutting allowance in this case is about 200 μm and has been provided as a substrate.

(Problem of the invention) However, using a high-purity aluminum ingot, casting a molten Al-Mg alloy melt that has been sufficiently degassed, and then casting a material that has undergone appropriate plastic working such as rolling or extrusion Plasma CVD on a substrate finished by cutting
When a-Si photoconductor is formed by a known method such as a method, a hemispherical projection defect (hereinafter referred to as a projection defect) occurs on the film, which causes an image defect. . Therefore, an object of the present invention is to provide a method for manufacturing a substrate in which the occurrence of projection defects which become image defects is prevented.

(Means for Solving the Problems) The inventors of the present invention have used an Al-Mg-based alloy sub-layer which is used when a-Si photoconductor is subjected to a film-forming treatment and is less likely to cause a defect portion which becomes an image defect on the photoconductor surface. When a method for producing a straight was examined, a defect portion which was conventionally considered as an image defect on the surface of the photoconductor occurred even when the substrate was produced using a material having a small gas content, and the intermetallic compound particles As a result of observing in detail that defects also occur at locations unrelated to the locations of scratch defects and scratches, and most of these defects do not have roots in the substrate of the substrate, It was found to have its roots inside the membrane. As a result of further research, the inventors have found that the surface layer of the material from which the substrate is manufactured contains a significantly higher amount of gas than the average gas content of the entire material. The present invention has been completed by finding that when the surface layer is removed by a critical thickness or more before film-forming treatment of an a-Si photoreceptor, the generation of defective portions which become image defects on the surface of the photoreceptor can be significantly reduced. Is.

That is, the present invention, Mg1.5 ~ 5.0 wt% and Cu 0.001 ~ 0.2
An aluminum alloy wrought material containing 5 wt% and consisting of balance Al and impurities with the total amount of Fe and Si in the impurities being 0.15 wt% or less is thickened before the film forming process of the a-Si photoconductor. 40
It is a method for manufacturing an aluminum alloy substrate for an a-Si photoconductor, which is characterized by removing 0 μm or more.

(Operation) First, the reasons for adding and limiting the alloy components will be described.

Mg1.5 to 5.0 wt% Mg is for imparting strength, and is less effective below the lower limit, and becomes sensitive to stress corrosion cracking above the upper limit and lowers durability. Further, coarse β-AlMg phase particles are likely to be generated, and the surface finish is lowered when the surface layer of the raw material is cut when manufacturing the substrate. By the way, the gas contained in the surface layer has hydrogen gas as a main component, and it is considered that this hydrogen gas has penetrated into the aluminum material as hydrogen atoms due to the reaction of moisture in the atmosphere with aluminum. Then, it is considered that hydrogen gas is concentrated on the surface. When the inventors measured the gas content, the surface layer 0.4 mm thick from the surface had an average of 0.4 cc / 100.
g Al, and the layers other than the surface layer had an average of 0.25 cc / 100 g Al. It is presumed that such a gas is released into the reaction gas at the time of film formation of the a-Si photoconductor, which is mixed in the a-Si photoconductor film and leads to the formation of protrusion defects. Also, as the Mg content increases, hydrogen atoms tend to be contained, so
If the content of is higher than the upper limit, even if the surface layer of the material is sufficiently removed during the production of the substrate, the generation of defective portions that become image defects on the surface of the photoreceptor cannot be significantly reduced. The preferred content is 2.0 to 3.5 wt%.

Cu 0.001 to 0.25 wt% Cu is for reducing the gas content in the surface layer. This seems to be because when Cu atoms are contained in the aluminum alloy, hydrogen atoms tend to form hydrogen molecules on the aluminum surface and prevent hydrogen atoms from entering the inside. That is, below the lower limit, the effect is small, and above the upper limit, not only the effect is saturated, but also the corrosion resistance decreases.

In addition to Mg and Cu, 0.1 wt% or less of Mn, 0.1 wt% or less of Zr, C
r less than 0.1 wt%, Zn less than 0.3 wt%, Ti less than 0.1 wt%,
The addition of an element of 0.02 wt% or less of B for the purpose of refining recrystallized grains or preventing casting cracks does not impair the object of the present invention.

Fe and Si are mixed as impurities from the above-mentioned high-purity (99.85 wt% or more) aluminum ingot, additive element materials, tools during melting, etc., but these elements are
Since an intermetallic compound such as Al ₃ Fe, AlFeSi, and Mg ₂ Si is formed and causes a defective portion which becomes an image defect on the surface of the photoconductor, the total content of Fe and Si is set to 0.15 wt% or less. Preferably Fe
It is desirable that the content is 0.10 wt% or less and Si is 0.10 wt% or less.

The alloy with the above composition is melted by a conventional method, then MgO,
Filtered to remove oxides such as Al ₂ O ₃ , the treated molten metal was cast into a slab or billet by a water-cooled semi-continuous casting method, and subjected to one-stage or two-stage homogenization treatment at normal temperature. After that, hot rolling, cold rolling or extrusion processing is carried out by a conventional method to produce a plate-shaped or drum-shaped substrate material, and then the a-Si photoreceptor is film-formed on this material. Thickness of surface layer is 400μm or more, preferably 500μm
The above is removed to obtain a substrate. This removal means
Methods such as cutting, polishing, and chemical dissolution can be applied, but cutting is preferable to achieve the most accurate and efficient substrate geometry. Removal amount of surface layer is 400μ
When it is m or less, it is impossible to prevent the generation of defective portions which become image defects on the surface of the photoconductor.

Substrates manufactured with the surface layer removed were a-Si
By forming a protective means such that the surface of the substrate does not react with moisture in the atmosphere and hydrogen gas does not enter, such as by storing it in dry air until the photoreceptor is film-formed. The period up to is not specified.

(Example) Example 1 A molten aluminum alloy melted, degassed and filtered by a conventional method was continuously cast into a billet having a diameter of 325 mm, and homogenized at 530 ° C for 10 hours. , Extruded by an indirect extruder and then drawn to have an outer diameter of 90.3-92.0mm
× Inner diameter was 80.0 mm, and annealed at a temperature of 350 ° C. for 2 hours to obtain a raw tube. The composition of the tube is Mg2.5wt%, Cu0.002wt%,
Fe was 0.04 wt% and Si was 0.02 wt% as impurities, and the balance was Al and other impurities. Next, using a natural diamond R bit, the raw tube was mirror-finished while changing the cutting amount to manufacture a substrate having an outer diameter of 90.0 mm and an inner diameter of 80.0 mm. A 20 μm thick a-Si film was formed on the substrate by a glow discharge decomposition method using SiH ₄ gas as a source gas.
A photoconductive photoreceptor was formed. The presence or absence of protrusion defects on the surface of the a-Si photoconductor film was inspected with an inspection mirror at a magnification of 100. In addition, these were mounted on an actual machine and a transfer test was performed to inspect for the presence or absence of color loss. Regarding the presence or absence of color loss, there was nothing that did not cause a defect, and there was a defect that did not. The results are shown in Table 1.

From the results shown in Table 1, a substrate manufactured by sufficiently removing the surface layer of the tube (Example of the present invention: sample numbers 1-1, 1-2, 1
In the case where the a-Si photoconductor was subjected to the film formation process in -3), no protrusion defects were generated on the film surface, and color loss did not occur even when the actual machine test was performed, but the surface layer of the elementary tube was sufficiently deleted. Untreated substrate (Comparative example: Sample No. 1-4,1-
In the case of using 5), it can be seen that a protrusion defect occurs on the film surface, and color loss occurs in an actual machine test.

Example 2 Aluminum alloys of various compositions were melted and cast by the same method as in Example 1, the resulting billet was subjected to homogenization treatment at a temperature of 540 ° C. for 10 hours, extruded by an indirect extruder, and then drawn. Then, it was annealed at a temperature of 340 ° C. for 2 hours to obtain a raw tube.
The composition is shown in Table 2 and the mechanical properties are shown in Table 3.

1) is mixed as an impurity.

imp is an impurity other than 1).

Next, using a natural diamond R-bite,
A substrate having an outer diameter of 90.0 mm and an inner diameter of 80.0 mm was manufactured by cutting 0.50 mm and mirror-finishing. The substrate was inspected for corrosion resistance, mirror finish due to scratches, presence of projection defects on the surface of the a-Si photoconductor film, and presence or absence of color loss by an actual machine transfer test. Corrosion resistance is CASS
The test and the finished state of the mirror surface were visually observed, and the presence or absence of protrusion defects and the presence or absence of color loss were the same as in Example 1. The result is the third
Shown in the table.

From the results in Table 3, the examples of the present invention are excellent in each characteristic,
-It is understood that this is a suitable manufacturing method for a substrate for a Si photoconductor. On the other hand, it is understood that the comparative example is inferior in any of the characteristics and is not preferable as a method for producing a substrate for an a-Si photoconductor.

(Effects of the Invention) As described above, the present invention is an improvement in the process of removing the surface of the material sufficiently more than the amount conventionally cut, and the obtained substrate has a-Si It is possible to form a uniform film when the photoconductor is subjected to a film forming process, and it is possible to reduce the occurrence of defects such as protrusion defects that cause image defects. Therefore, the aluminum alloy substrate according to the present invention has effects such as high productivity and high yield in film formation of an a-Si photoconductor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location G03G 5/08 350 9223-2H

Claims (1)

[Claims] 1. Mg1.5-5.0 wt% and Cu0.001-0.25 wt%
Containing Al and the balance Al and Fe in the impurities.
And an aluminum alloy wrought material having a total amount of Si of 0.15 wt% or less is removed by a thickness of 400 μm or more before the film forming process of the amorphous silicon photoconductor. Production method.