JPH0574062B2 - - Google Patents

Description

[Detailed description of the invention]

"Purpose of the Invention" (Industrial Application Field) The present invention relates to an aluminum substrate for an organic photoreceptor, which provides high-quality images with fewer image defects such as white spots when obtaining an image with a photoreceptor in an electrophotographic method. An object of the present invention is to provide an aluminum substrate for an organic photoreceptor that can be used as an organic photoreceptor. (Prior art) Equipment such as copiers and optical printers that can obtain images using electrophotography use photoconductors as photoconductors.
Photoreceptor materials such as Se, CdS, ZnO, and amorphous silicon are used in consideration of their characteristics and uses, but organic photoreceptors are particularly widely used because they are low in cost and do not pollute the environment. However, such photoreceptor materials are coated in one layer or in multiple layers on the surface of a light and moldable aluminum substrate in the shape of a flat plate, cylinder, belt, etc., and when copying, a specific wavelength of light is applied to the photoreceptor material. Copying is performed by irradiating a light beam to charge the area, electrically attaching printing powder, and transferring it to paper. If there is something structurally or compositionally different on the surface of the substrate, the charged state of the photoreceptor material will be uneven.
The adhesion of printing powder is disturbed, resulting in poor image quality such as white spots. As the aluminum substrate for the organic photoreceptor mentioned above, JIS1050, 1100 (pure aluminum), JIS3003
(Al-Mn alloy), JIS5000 (Al-Mg alloy),
Molded objects such as extruded materials and ironed materials according to JIS6000 (Al-Mg-Si alloy) are precision-finished using cutting tools such as diamond tools. On the other hand, such aluminum alloys contain relatively large amounts of Si and Fe as impurities, and elements such as Mn are added to give strength as per JIS 3003, so they do not form a solid solution in aluminum. These difficult elements such as Si, Fe, and Mn crystallize in the matrix as intermetallic compounds, and these crystallized substances are distributed in high density on the precisely finished surface of the substrate and affect the charged state of the photoreceptor material. This disturbs the adhesion of printing powder and causes poor image quality such as white spots, so it is necessary to reduce the content of Si and Fe, or to adjust the amount of elements such as Mn added. Proposed. As mentioned above, it is difficult to obtain ironed materials with a long axis relative to the diameter, and the jigs and equipment such as molds are expensive, so it is common to use extruded products. There are two ways to obtain a solid bit: the mandrel method, in which a mandrel is passed through a hollow billet and extrusion molding; and the port holder method, in which a solid bit is separated in a die and then welded again at the exit of the die for extrusion molding. Not only does it require special extrusion equipment to move the mandrel and the extrusion spot relative to each other, but it also increases production costs because it is necessary to first prepare a hollow billet. On the other hand, the latter porthole die method can be manufactured at low cost because it can be formed using only a die. (Problems to be Solved by the Invention) In an organic photoreceptor substrate made of an Al-Mg alloy, even if the contents of Si and Fe are reduced and elements such as Mn are adjusted to an appropriate level, poor image quality remains unresolved. That is, when the present inventors melt Al-Mg alloy,
As a result of examining substrates in which the content of Si and Fe is limited and the addition of elements such as Mn is suppressed, it has been confirmed that even in such cases, the occurrence of image quality defects such as white spots cannot be effectively reduced, I learned that there are unresolved issues regarding such poor image quality. However, as a result of various studies regarding the above-mentioned image quality defects, the inventors found that the image quality defects are not only caused by crystallized substances, but also by corrosion residues generated by microscopic local corrosion on the surface of the substrate, which affect the charged state of the photoreceptor. It was confirmed that unevenness occurred and the adhesion of printing powder was disturbed. It has been found that in molded products extruded using the porthole die method, which can be produced at low cost as mentioned above, image quality defects such as white spots occur in the welded area on the die exit side. It is known that there are many unresolved issues. "Structure of the Invention" (Means for Solving the Problems) As a result of repeated studies in view of the above-mentioned circumstances, the present invention has been developed by adding Cu to an Al-Mg alloy and reducing the content of Si and Fe as impurities. It has been confirmed that if the amount is as small as possible, and the ratio of Si and Fe is within a specific range, the Si and Fe crystals will be finely dispersed, their quantitative proportion will be small, and local corrosion will be less likely to occur. When the ratio of Si to Fe is within a certain range, the size of the crystal grains in the welded part of the extruded body with a porthole die becomes uniform, resulting in a high-quality image with fewer image defects. I succeeded in tightening it. That is, the present invention is as follows. 1 In terms of weight, Mg: 0.2~6.0%, Cu: 0.02~
Contains 0.15%, the balance consists of aluminum and impurities, and Si as an impurity is 0.20% or less,
An aluminum substrate for an organic photoreceptor, characterized in that Fe is 0.20% or less, and the ratio of Si to Fe is within the range of 0.2≦Si/Fe≦1.8. 2. The aluminum substrate for an organic photoreceptor as described in 1 above, wherein the area ratio occupied by the intermetallic compound in the 300 μm surface layer of the aluminum substrate is 0.5% or less, and the average value of the major axis of the intermetallic compound is 3 μm or less. 3. The aluminum substrate for an organic photoreceptor as described in 1 above, which has a pitting area ratio of 0.2% or less. 4 In terms of weight, Mg: 0.2~6.0%, Cu: 0.02~
0.15%, Mn: 0.08% or less, the balance consists of aluminum and impurities, Si as impurities is 0.20% or less, Fe is 0.20% or less, and the ratio of Si to Fe is 0.2≦Si/ An organic photoreceptor aluminum substrate characterized by Fe≦1.8. 5. The aluminum substrate for an organic photoreceptor as described in 4 above, wherein the area ratio occupied by the intermetallic compound in the 300 μm surface layer of the aluminum substrate is 0.5% or less, and the average value of the major axis of the intermetallic compound is 3 μm or less. 6. The aluminum substrate for an organic photoreceptor as described in 4 above, which has a pitting area ratio of 0.2% or less. (Function) The composition range of each component as described above is explained in terms of wt% (hereinafter simply referred to as %) as follows. Mg: 0.2-6.0%. Mg is an element that easily forms a solid solution in aluminum, improves machinability, allows for highly accurate finishing, and adds strength to the alloy.If it is less than 0.2%, these effects must be properly determined. I can't. If it exceeds 60%, stress corrosion cracking susceptibility becomes significant, and even if a small amount of Si is present,
Generates Mg ₂ Si compounds and causes poor image quality. In order to avoid that the size of the crystal grains in the welded part of the molded body extruded by the porthole die method is significantly different from the size of the crystal grains in the non-welded part, the upper limit is _0.5 %. Prevents precipitation and reduces corrosion resistance. In other words, when extrusion molding is performed using a porthole die, the resistance between the flow and the dust during separation within the die is large, so the alloy temperature at the welding part on the die exit side increases, suppressing the formation of Mg ₂ Si compounds. . The preferred range is 0.3-1.3%. Cu: 0.02~0.15%. Cu not only gives strength to the alloy, but also electrochemically suppresses local corrosion, improves the charging state of the photoreceptor, and eliminates poor image quality.
If it is less than 0.02%, this effect is insufficient;
On the other hand, if the content exceeds 0.15%, corrosion will be accelerated. The preferred range is 0.04~
It is 0.10%. As mentioned above, the details of how adding a small amount of Cu suppresses local corrosion are not fully understood, but it is possible to shift the corrosion potential of the matrix to the noble side by adding a small amount of Cu to an Al-Mg alloy. It is clear that for a matrix such as an Al-Fe compound, which is generated by Fe etc. contained as an impurity, the potential shift to the noble side reduces the potential difference with the compound. It is presumed that this makes it difficult to corrode. Si: 0.20% or less. Fe: 0.20% or less. 0.2≦Si/Fe≦1.8. Si and Fe are elements contained as impurities, and when their content exceeds the upper limit, Al
- Fe compounds or Mg ₂ Si compounds crystallize and become a starting point for localized corrosion, and also cause scratches during surface finishing, and tend to form a surface deterioration layer where processing strain remains, causing corrosion in the area. In either case, it becomes a cause of image defects. In order to further improve the image quality, it is necessary to set the ratio of Si and Fe to 0.2≦Si/Fe≦1.8, which means that Mg ₂ Si or Al crystallized by Si or Fe
The purpose is to crystallize the -Fe compound as an Al-Si-Fe compound that has better machinability than these compounds, reduce the surface deterioration layer, and suppress the occurrence of local corrosion. When /Fe≦1.8, Al-Si-Fe compounds crystallize frequently, and when Si/Fe≧1.8, Mg ₂ Si
Crystallization of the compound increases, which is not preferable in any case. Note that this Si/Fe is preferably 0.4
-1.2, more preferably 0.5-1.0. Mn: 0.08% or less. The addition of a small amount of Mn turns the Al-Si-Fe compound into an Al-Si-Fe-Mn compound with better machinability, forming a precise finished surface, reducing the surface deterioration layer,
Aim to optimize image quality. This effect is particularly noticeable when the Si and Fe contents are high, which is preferable, but when the content exceeds 0.08%,
It becomes easier to generate AlMn ₆ compounds, which actually deteriorates machinability and causes poor image quality. Other ingredients. 0.005% usually added to prevent Mg oxidation
Be to a certain degree is acceptable and is particularly effective when the Mg content is high. In addition, when producing such an alloy, impurities that may be mixed in from the aluminum base metal, etc., include up to 0.1% of Zn and 0.05% of Cr.
The content of up to 0.05% of V and up to 0.02% of Ni is permissible because it does not interfere with the effects of the present invention and does not cause poor image quality. In addition, in order to further improve the image quality of the substrate with the above-mentioned composition, the surface layer of the substrate is 300 μm thick.
0.5% of the area occupied by intermetallic compounds between
The average size of the long axis should be 3 μm or less, or the area ratio of the pitting corrosion area should be 0.2%.
The following is desirable. As mentioned above, by setting the upper limit of Mg to 1.5%, the size of crystal grains in the welded part of the molded body extruded using the porthole die method is only slightly different from that in other non-welded parts. A substrate with good image quality can be obtained. The product is manufactured using aluminum ingots with a purity of JIS Class 1 or Special Class 2, especially JIS Special Class 2 or higher, and cast using a semi-continuous water-cooled casting method to finely disperse the crystallized intermetallic compounds. to obtain a slab or billet. The slab or billet thus obtained is subjected to a homogenization treatment by holding it at a temperature of 450 to 560 ° C for 5 hours or more (for example, 5 to 15 hours),
Then hot rolled and cold rolled to a thickness of 1 to 3
This plate is made into a plate with a diameter of approximately mm, and this plate is ironed to form a blank pipe or other material with a desired cross-sectional shape, or after homogenization treatment, extrusion molding is performed using a porthole die, and the resulting molded body is drawn into the desired shape. Made of raw pipes with cross-sectional shapes and other shapes. The surface of such a raw pipe is precisely finished using a diamond tool or a similar tool to form a base. (Example) Specific examples of the present invention will be described below. Example 1 Molten aluminum alloys having the respective compositions shown in Table 1 below were melted using JIS special class 1 aluminum ingot,
After degassing, non-metallic inclusions in the molten metal were removed through a porous tube filter, and then a billet of 325 mmφ was cast by a semi-continuous water-cooled casting method. These billets are heated at a temperature of 500 to 560℃ for 5 to 50 minutes.
After being held for 15 hours and homogenized, extrusion was performed using a mandrel method, cold drawing was performed to obtain an aluminum tube with an inner diameter of 80 mmφ and a wall thickness of 1.2 mm, and the surface of the tube was polished using a diamond tool. It was precisely finished and used as a base material, which was then used as a test material. Test materials 1 to 7 satisfy the conditions according to the present invention, whereas test material 8 does not contain Cu (Mg is low within the range of the present invention), and test material 9 has Cu of 0.23.
%, which is higher than the range of the present invention, and sample material 10 has Fe content of 0.28%.
This is still higher than the range of the present invention, and Si/Fe is also 0.18.
The following test materials do not fall within the scope of the present invention.
No. 11 has high Si and Si/Fe of 2.75, which is higher than the range of the present invention. In addition, although the composition of each component of sample material 12 satisfies the range of the present invention, Si/Fe is 2.1, which slightly exceeds the range of the present invention, and sample material 13 does not contain Cu (Mg
Although it is within the scope of the present invention, the test material
Sample No. 14 has Cu exceeding the range of the present invention, and Sample No. 15 has Mg of 0.1%, which is below the range of the present invention. Furthermore, sample material 16 has a Mg content of 6.7%, which exceeds the scope of the present invention, and sample material 17 does not contain Mg.
Fe is 0.28%, which exceeds the range of the present invention, and sample material 18 has a significantly high Fe content of 0.44%, and Mn is also 1.07%.
This is a very high case, and sample material 19 has a Si content of 0.41%.
This is the case when it is high. In addition, sample materials 20 and 21 contain Mn exceeding the range of the present invention;
22, while the individual contents meet the requirements of the present invention.
This is a case where the value of the Si/Fe ratio is 0.17, which is below the range of the present invention.

[Table] The occupancy rate and size of intermetallic compounds were measured for each sample material 1 to 16 obtained as above, and the corrosion rate was measured using the Cyas test method. The results are shown in Table 2 below. The measurement method is as follows. Occupancy of intermetallic compounds and their size. The sample material was cut along a plane passing through the axis, and the cross section was buffed and electrolytically polished.
The distance between 300 μm was measured using an image analysis device.
The measurement area is 100 x 100 μm ² for each sample.
Measurements were taken at 10 locations and averaged. In addition, the size was determined by measuring the major axis. Corrosion rate. After flattening the test material, the surface of the substrate was polished to Emery No. 1000, and corrosion was accelerated for 30 minutes using the JISH8681 Cass test method, and the pitting corrosion area was expressed as an area ratio. Image evaluation. Precision finished base with CTL and hydrazone,
A phthalocyanine-based organic photoreceptor was coated on CGL to a total film thickness of 25 μm, and the entire surface was copied in pure black using the normal black printing method, and the number of white defects in the black screen was evaluated. The evaluation criteria were A for those with no defects, B for those with no defects in practical use, and C for those with defects that would cause no problem in practical use.

[Table] That is, according to the above table, the samples according to the present invention (sample numbers 1 to 7) all have a small intermetallic compound occupation rate, a small average particle size, a small corrosion rate, and no occurrence of white defects. Few. On the other hand, all of the comparative examples were inferior and had many white defects, and none of them reached the level of the present invention in the overall evaluation, and all of them were poor. Example 2 Each molten aluminum alloy having the composition shown in Table 3 below is melted using JIS special class 1 aluminum ingot, degassed, and then filtered using a porous tube filter to remove non-containing substances in the molten metal. Metal inclusions were removed and an ingot of 203mmφ was made by semi-continuous water-cooled casting. This material is then homogenized at 500 to 560°C for 5 to 15 hours, extruded using a porthole die method, and then cold drawn to form an aluminum alloy with an inner diameter of 80 mmφ and a wall thickness of 1.2 mm. The surface of the raw tube was precisely finished using a diamond tool to obtain a test material as a base material. Test materials 1 to 6 all contained Mg of 1.5% or less and other component compositions to avoid the crystal grain size in the welded part from being significantly different from that in the non-welded part during porthole die extrusion molding. This is an inventive material that satisfies the requirements of the present invention, and test material 7~
Sample No. 11 has a Mg content of 0.7%, which is relatively low within the range of the present invention, but sample material 7 does not contain Cu, and sample material 8 has a Cu content of 0.23%, which exceeds the upper limit of the present invention. Sample material 9 has Fe of 0.28%, which is above the upper limit of the present invention, and sample material 10 has Fe of 0.28%.
Si was 0.22%, which exceeds the range of the present invention, and sample material 11 had Si/
Fe exceeds the upper limit of the present invention at 2.1, and both are comparative materials. Sample materials 12 and below are also comparative materials; sample material 12 does not contain Cu, sample material 13 has Cu that is higher than the upper limit of the present invention, and sample material 14 has Mg of 0.1%, which is lower than the lower limit of the present invention. In sample material 15, the Mg content was 1.8%, which exceeded the upper limit for porthole extrusion molding. In addition, sample material 16 does not contain Mg and has Fe content of 0.28%, which is above the upper limit of the range of the present invention, and sample material 17 does not contain Mg.
Fe is even higher at 0.44%, Mg is also 0.1%, which does not reach the lower limit of the present invention, and the final sample material 18 has a Si content of 0.41%.
Both have a high Mg content of 0.52% and contain no Cu, and are comparative materials.

[Table] However, for each sample material obtained with such a porthole die, the occupancy rate and particle size of the intermetallic compound were measured in the same manner as in Example 1, and
In addition, the cast test corrosion rate was determined using the same method as described in Example 1, and the image quality evaluation such as image defects was performed in the same manner as in Example 1. The following Table 4 summarizes the results of examining the distribution by microscopic observation using Mr. Tatsuker's solution.

[Table] That is, test materials 1 to 6 according to the present invention all showed favorable results, whereas comparative materials 7 to 18
All of them were inferior in multiple measurement evaluation results, and it was confirmed that the one according to the present invention could provide a preferable substrate by the advantageous porthole die method. ``Effects of the Invention'' As explained above, the present invention can be used as an aluminum substrate for organic photoreceptors such as copying machine drums and optical printers, with fewer image defects such as white spots, good image quality, and high yield. This invention has the advantage of accurately obtaining a preferred substrate even in the porthole die method, which is advantageous in terms of equipment and production costs, and is an industrially highly effective invention. .

Claims (1)

[Claims] 1. In terms of weight, Mg: 0.2 to 6.0%, Cu: 0.02 to
Contains 0.15%, the balance consists of aluminum and impurities, with Si as impurities of 0.20% or less and Fe as impurities.
An aluminum substrate for an organic photoreceptor, characterized in that the content is 0.20% or less, and the ratio of Si to Fe is within the range of 0.2≦Si/Fe≦1.8. 2. The aluminum substrate for an organic photoreceptor according to claim 1, wherein the area ratio occupied by the intermetallic compound in the 300 μm surface layer of the aluminum substrate is 0.5% or less, and the average value of the major axis of the intermetallic compound is 3 μm or less. 3. The aluminum substrate for an organic photoreceptor according to claim 1, which has a pitting area ratio of 0.2% or less. 4 In terms of weight, Mg: 0.2~6.0%, Cu: 0.02~
0.15%, Mn: 0.08% or less, the remainder consists of aluminum and impurities, and contains Si as an impurity.
0.20% or less, Fe 0.20% or less, and this Si
An organic photoreceptor aluminum substrate characterized in that the ratio of Si and Fe is within the range of 0.2≦Si/Fe≦1.8. 5. The aluminum substrate for an organic photoreceptor according to claim 4, wherein the area ratio occupied by the intermetallic compound in the 300 μm surface layer of the aluminum substrate is 0.5% or less, and the average value of the major axis of the intermetallic compound is 3 μm or less. 6. The aluminum substrate for an organic photoreceptor according to claim 4, which has a pitting area ratio of 0.2% or less.