JPH0428774B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD OF THE INVENTION This invention relates to electrophotographic photoconductive member precision-machined supports made from improved aluminum alloys. [Prior Art] Aluminum alloys are widely used in various structures such as building materials and automobile parts, but in particular, they are used as constituent members of electrical devices (electronic devices) that require precision processing, such as supports for photoconductive members. Its usage is increasing. However, for example, general-purpose aluminum alloys standardized by the Japanese Industrial Standards (JIS) for wrought materials, castings, die castings, etc. include Mg, Cu, Mn,
Various impurity components are contained together with various compositional components including actively added components such as Si and Zn, and some of these may be localized in the structure as inclusions or may cause grain boundary steps. or exist as granular precipitates near the surface, impairing workability during precision machining, and as a result, deteriorating the characteristics of electronic components etc. made of aluminum alloys. To explain this situation in more detail with respect to electrophotographic photoconductive members, for example, electrophotographic photoreceptors are usually constructed by providing a photoconductive layer on the surface of a cylindrical support made of an aluminum alloy. Various organic and inorganic photoconductive substances are used as materials for the photoconductive layer. For example, amorphous silicon (hereinafter referred to as a-Si) whose dangling bonds are modified with a monovalent element has excellent optical properties. Due to its conductivity, abrasion resistance, and heat resistance, it is expected to be used as a material for photoconductive layers. In order to put this a-Si into practical use, in addition to the a-Si photoconductive layer,
It is necessary to use a charge injection blocking layer that prevents charge injection from the support, a surface protection layer such as SiN _x or SiC _x , and to form a multilayer structure depending on the purpose. The uniformity of the photoconductive member at this time is extremely important, and if there are defects such as non-uniform photoconductive properties or pinholes, it will not only be impossible to provide a beautiful image;
It becomes impractical. [Problems to be Solved by the Invention] It is known that the form of the film of a-Si in particular is greatly influenced by the surface shape of the support. In particular, the surface condition of the support is extremely important for large-area electrophotographic photoreceptor drums that require almost uniform photoconductive properties in most parts, and the presence of defects on the surface of the support will affect the uniformity of the film. The photoconductivity becomes poor and a columnar structure or spherical protrusion is formed, which causes photoconductive non-uniformity. Therefore, when using an aluminum alloy tube material as a support, in the process of performing various precision cutting or polishing processes such as mirror finishing or embossing on the surface, the various inclusions mentioned above may occur, for example, so-called hard spots. If a hard part exists, it will cause cutting resistance against the cutting tool during the mirror-finishing process, for example, and cause defects on the aluminum cylinder surface, resulting in cracks of about 1 to 10 μm, egre-like scratches, etc. on the aluminum support surface. Furthermore, fine irregularities,
Alternatively, it is a factor that causes streak-like scratches. However, in the past, inclusions, H ₂
To reduce blister caused by gas,
It is necessary to use an Al alloy base with various measures taken, and these measures will cause
Addition of processes and increase in costs could not be avoided. Furthermore, electrophotographic photoreceptors are repeatedly rubbed by blades, fur brushes, etc. in electronic processes to remove residual toner. At this time, increasing the hardness of the support as well as the abrasion resistance of the surface of the photoconductive layer is good for improving the durability of the photoreceptor, so there have been cases of using high-hardness Al materials, etc. Similarly, in a-Si photoreceptors in particular, problems arise due to precipitates in the Al structure, and this is particularly noticeable in high-concentration Si-based Al alloys. Therefore, the present inventors set the Bitkers hardness to 50Hv to 100Hv when the silicon content in the aluminum alloy is 2 to 7% by weight.
The present invention has been completed based on the discovery that the above-mentioned conventional problems can be solved and that the size of the included inclusions can be made finer. The first object of the present invention is to produce an electrophotographic photoconductor manufactured from an aluminum alloy, which is suppressed from the influence of inclusions and whose adaptability to precision processing is further improved by optimizing the forming method. An object of the present invention is to provide a precisely processed support for a member. A second object of the present invention is to provide a support for an electrophotographic photosensitive drum, which is particularly desired to have an accurate surface shape and high dimensional accuracy through precision processing. [Means for Solving the Problems] The precision-processed support for electrophotographic photoconductive members of the present invention contains silicon in an amount of 2% by weight or more and 7% by weight or less, the balance being aluminum and impurities, and hydrogen as the impurity is for 100 grams of aluminum
1.0cc or less, and iron as an impurity is
2000 ppm or less, and is characterized by being manufactured from an alloy having a Bitkers hardness of 50 Hv or more and 100 Hv or less. General-purpose aluminum alloys generally contain precipitates and inclusions caused by impurities that are unavoidably mixed in during processes such as refining and melting, in addition to alloying ingredients that are actively added as necessary. There are This causes deterioration of the characteristics of the photoconductive member support. For example, silicon is difficult to form a solid solution with aluminum;
Si, SiO ₂ , Al-Si compounds, Al-Fe-Si compounds,
Al exists as an Al-Si-Mg compound or as Al ₂ O ₃ in the aluminum structure, for example, in the form of an island. Fe, Ti, etc. also appear as oxides and hard grain boundary precipitates and hard spots. On the other hand, when precision machining aluminum alloy,
During processing, the surface hardness of the aluminum alloy is one of the factors that greatly influences the surface condition after processing. In the present invention, we focused on silicon, which has a great effect on the hardness of aluminum alloys and is also a factor in causing hard spots, and by suppressing the silicon content to 7% by weight or less, we can reduce the increase in the number of hard spots in aluminum alloys. By keeping the surface hardness within the allowable range and by adding 2% by weight or more of silicon, the overall distribution of surface hardness is made safer, which improves workability in precision machining, thereby improving overall precision. As a result of research, we were able to achieve sufficient processability for practical use. That is, in the aluminum alloy used in the present invention, silicon, which is a component that causes hard spots, is deliberately set in the range of 2% to 7% by weight, the overall distribution of surface hardness is stabilized, and the silicon content is made to be stable through heat treatment, compression treatment, etc. It is an aluminum alloy whose hardness has been adjusted to between 50Hv and 100Hv. The aluminum alloy thus obtained can suppress the occurrence of cracks of about 1 to 10 μm, rough scratches, fine irregularities, or streak scratches as described above. In a more preferred embodiment of the present invention, in an aluminum alloy having a silicon content of 2 to 7% by weight, the Vickers hardness is set to 50Hv to 100Hv, and the sizes of the various inclusions described above (represented by the maximum length of the inclusion particles) are determined. When the particle size (particle size) is 10 μm or less, it is preferable because the workability during precision processing and the properties and durability of the support for electrophotographic photoconductive members obtained by precision processing are improved to an unexpected degree. A more preferable size of the inclusions is 5 μm or less. The hardness of the aluminum alloy used in the present invention
Specific methods for setting the temperature to 50 Hv or more and 100 Hv or less include the following methods. The aluminum alloy having the alloy composition specified in this invention has a Vickers hardness of
The Vickers hardness can be controlled to a desired value within the range of 50 Hv to 100 Hv by performing both heat treatment and plastic working or only plastic working. As a specific heat treatment, it is desirable to perform an annealing treatment, a containerization treatment, a tempering treatment, or the like. As an annealing treatment, for example, 1 to 2
It is desirable to hold it for about an hour and then slowly cool it.
This treatment can reduce the hardness of the aluminum alloy obtained by casting. Solution treatment for uniformly solid solutionizing the alloying elements in the aluminum alloy is preferably carried out at a temperature of about 500 to 525°C, preferably for about 8 to 10 hours. It is preferable to carry out the reaction at a temperature of about 150 to 170°C for about 5 to 10 hours. By performing the solution treatment and tempering treatment under these conditions, a Vickers hardness of about 80 Hv to 90 Hv can be obtained. Next, plastic working will be explained. The aluminum alloy as obtained by casting or the aluminum alloy that has undergone the above heat treatment process is subjected to plastic working such as rolling, extrusion, drawing, and drawing depending on the intended use of the aluminum alloy. These plastic workings cause work hardening of the aluminum alloy. The hardness of the aluminum alloy can be controlled to 50 Hv or more and 100 Hv or less by appropriately selecting the heat treatment conditions, plastic working method, conditions, etc. described above, and repeating the heat treatment and plastic working in some cases. Reduce the size of inclusions in aluminum alloy to 10μm
For example, as a specific method to suppress the following,
In addition to using a ceramic filter with a small opening diameter when melting aluminum alloys, we take a method to fully utilize the effect of the filter under sufficient management. Specifically, when the filter becomes clogged to a certain extent, Use the lot. Further examples include measures to prevent mixing of melting furnace materials and increasing the thickness of the slag surface. The iron contained in aluminum alloys is a combination of aluminum and silicon that coexists with the Fe-Al system and Fe-Al-Si.
It forms intermetallic compounds and appears as hard spots in the aluminum matrix. In particular, these hard spots increase rapidly when the iron content increases beyond 2000 ppm, and have an adverse effect on, for example, mirror cutting. Therefore, the preferred iron content in the aluminum alloy of the present invention is 2000 ppm.
Below, it is further below 1000ppm. Furthermore, hydrogen contained in aluminum alloys causes structural abnormalities such as pores (blisters).
This may impair workability during precision machining or cause deterioration of the characteristics of electronic components obtained through precision machining. This inconvenience is caused especially when the amount of hydrogen in aluminum alloy is 1.0 per 100 grams of aluminum.
It can be solved by suppressing it to cc or less, more preferably 0.7cc or less. Iron content in aluminum alloy
As a specific method to keep it below 2000ppm, use a highly pure Al base metal as a raw material, for example,
Use products that have undergone repeated electrolytic refining. Another method is to thoroughly control each process of melting and casting. A specific method for suppressing the amount of hydrogen contained in aluminum alloy to 1.0 cc or less per 100 grams of aluminum is to blow chlorine gas into the molten metal as a degassing step when melting the Al alloy, and to Examples include a method in which the existing H ₂ gas is removed as HCl, or a method in which the molten Al alloy is held in a vacuum furnace for a certain period of time, and the H ₂ gas present in the alloy structure is diffused and removed into the vacuum. The precision-machined support for electrophotographic photoconductive members of the present invention made of the above-mentioned aluminum alloy exhibits sufficiently excellent desired properties, but if desired, in order to further improve the above properties, or in addition, other materials may be added. Other alloying components can also be added to impart these properties. Such alloy components (addition amount) include Mg (0.35-1.5% by weight), Cu
(0.1-0.4 wt%), Mn (0.03-0.8 wt%), Cr
(0.03-0.35 wt%), Zn (0.1-0.25 wt%), Ti
(0.1 to 0.15% by weight), etc. In the present invention, when selecting the composition of the aluminum alloy from within the above composition range, characteristics depending on the purpose of use, such as precision machinability, dimensional accuracy, mechanical strength, corrosion resistance, and heat resistance, are taken into consideration. You can select it as appropriate. The aluminum alloy used in the present invention undergoes plastic working such as rolling and extrusion, and then undergoes precision processing that involves mechanical methods such as cutting or polishing, or chemical or physical methods such as chemical etching. Depending on the purpose, heat treatment, cooking, etc. are combined as needed to shape the material into an appropriate shape depending on the purpose of use. For example, when forming a tubular component that requires strict dimensional accuracy such as an electrophotographic photoreceptor drum, a porthole extruded tube or a mandrel extruded tube obtained by ordinary extrusion processing is further cold-drawn. It is preferable to use a drawn tube obtained by Using a tube like this,
For example, when the tube surface is subjected to precision machining that involves a mechanical method such as cutting or polishing for mirror finishing, embossing, etc., or a chemical or physical method such as chemical etching, it is used in the present invention. The properties of aluminum alloys are particularly pronounced. The aluminum alloy described above is polished to a surface roughness of R _nax = 1 μm or less using methods such as mirror finishing with diamond biting, cylindrical grinding, and rattan pink finishing.
Preferably, it is useful as a precisely processed support for electrophotographic photoconductive members that can be finished with a flatness of R _nax =0.05 μm or less. Hereinafter, an example of the structure of an electrophotographic photoconductive member using a-Si as a photoconductive material will be described using the precision-machined support for an electrophotographic photoconductive member of the present invention made from the above-mentioned aluminum alloy. Such a photoconductive member has, for example, a structure in which a charge injection blocking layer, a photoconductive layer (photosensitive layer), and a surface protection layer are sequentially laminated on a support. The shape of the support may be any shape such as a cylinder, a belt, or a plate, but for example, in the case of continuous high-speed copying for electrophotography, it is preferably an endless belt or a cylinder. The thickness of the support is determined appropriately so that a desired photoconductive member is formed, but if flexibility is required as a photoconductive member, the thickness is determined within a range that allows the support to function adequately. If inside, it will be made as thin as possible. However, even in such cases, the thickness is usually set to 10 μm or more in view of manufacturing and handling of the support, as well as mechanical strength. The surface of the support is given a mirror finish by, for example, mirror cutting to maintain the uniformity of the photoconductive member, and digital image information using coherent monochromatic light such as a laser beam is used as the light source of the photoreceptor. When used for recording, in order to prevent interference fringes, regular or irregular patterns, such as a spiral pattern, are formed by mechanical precision processing such as diamond cutting using a lathe, milling machine, etc., or other precision processing such as chemical etching. Fine irregularities of the shape are added. The charge injection blocking layer is composed of, for example, a-Si containing hydrogen atoms and/or halogen atoms, and as a substance that controls conductivity, it is made of a group or group of the periodic table, which is usually used as an impurity in semiconductors. Contains atoms of elements belonging to group . The thickness of the charge injection blocking layer is preferably 0.01 to 10 μm, more preferably 0.05 to 8 μm, and most preferably 0.07 to 5 μm. For example, Al ₂ O ₃ , SiO ₂ ,
A barrier layer made of an electrically insulating material such as Si ₃ N ₄ or polycarbonate may be provided, or a charge injection blocking layer and a barrier layer may be used together. The photoconductive layer is composed of, for example, a-Si containing hydrogen atoms and halogen atoms, and optionally contains a substance controlling conductivity separate from that used in the charge injection blocking layer. The layer thickness of the photoconductive layer is preferably 1 to 100 μm, more preferably 1 to 80 μm, and optimally 2 to 50 μm. The surface protective layer is composed of, for example, SiC _x , SiN _x , etc.
The layer thickness is preferably 0.01 to 10 μm, more preferably
The thickness is preferably 0.02 to 5 μm, preferably 0.04 to 5 μm. To form a photoconductive layer made of a-Si, a vacuum deposition method utilizing various conventionally known discharge phenomena such as a glow discharge method, a sputtering method, or an ion plating method is applied. Next, an example of a method for manufacturing a photoconductive member using a glow discharge decomposition method will be described. FIG. 1 shows an apparatus for manufacturing photoconductive members using a glow discharge decomposition method. The deposition tank 1 has a base plate 2
In the deposition tank 1, a cathode electrode 5 is provided, and a drum-shaped support made of an aluminum alloy having a specific composition on which an a-Si deposited film is formed. The body 6 is placed in the center of the cathode electrode 5 and also serves as an anode electrode. To form an a-Si deposited film on a drum-shaped support using this manufacturing device, first, close the raw gas inflow valve 7 and leak valve 8, open the exhaust valve 9, and exhaust the inside of the deposition tank 1. do. When the reading on the vacuum gauge 10 reaches approximately 5×10 ⁶ Toor, open the raw material gas inlet valve 7 and turn on the mass flow controller 1.
1, adjusted to a predetermined mixing ratio, for example,
A raw material mixed gas such as SiH ₄ gas, Si ₂ H ₆ gas, SiF ₄ gas, etc. is caused to flow into the deposition tank 1 . At this time, sedimentation tank 1
Adjust the opening degree of the exhaust valve 9 while checking the reading on the vacuum gauge 10 so that the internal pressure reaches the desired value. After confirming that the surface temperature of the drum-shaped support 6 is set to a predetermined temperature by the heater 12, the high frequency power source 13 is set to a desired power to generate glow discharge in the deposition tank 1. During layer formation, the drum-shaped support 6 is moved to the motor 1 in order to make the layer shape uniform.
4 to rotate at a constant speed. In this manner, an a-Si deposited film can be formed on the drum-shaped support 6. Hereinafter, the present invention will be explained in more detail based on Examples. Examples 1 to 4, Comparative Example 1 A diamond cutting tool with a tip curvature of 0.01 (mm ^-1 ) was installed in a lathe with an air damper for precision cutting (manufactured by PNEUMOPRECISION INC.) at a negative angle of 5° with respect to the cylinder center angle. It was set to obtain the rake angle. Next, five types of aluminum alloys with various Si contents, various Vickers hardnesses, and various inclusion sizes shown in Table 1 were applied to the rotating shaft flange of this lathe (for components other than Si,
The Mg content is 0.4% by weight, and the Fe content is 0.4% by weight.
1000ppm or less, hydrogen content is aluminum
A cylinder made of aluminum (1.0 cc or less per 100 grams, the remainder being Al) was vacuum chucked, and while using a combination of spraying white hot water from an attached nozzle and suctioning chips from the attached vacuum nozzle, Circumferential speed 1000
(m/min), feed rate 0.01 (mm/R),
Mirror cutting was performed so that the outer diameter was 80mmφ. The mirror-finished cylinders were inspected visually and with a metallurgical microscope for surface defects (aggressive scratches, cracks, and streak-like scratches) that had occurred after mirror-finishing, and the number thereof was determined. The amount of hydrogen contained in the cylinder was determined by cutting out a part of the manufactured cylinder and using it as a sample in a laboratory.
RH- made by Equipments Corporation
Measurements were made using Model IE according to its specifications. Next, on each of these mirror-finished aluminum alloy cylinders, using the photoconductive member manufacturing apparatus shown in Figure 1, photoconductive material was applied under the following conditions according to the glow discharge decomposition method described in detail above. The member was manufactured. Lamination order of deposited film Raw material gas used Film thickness (μm) Charge injection blocking layer SiH ₄ /B ₂ H ₆ 0.6 Photoconductive layer SiH ₄ 20 Surface protection layer SiH ₄ /C ₂ H ₄ 0.1 Aluminum cylinder temperature: 250℃ Deposited film Deposition chamber internal pressure during formation: 0.3Torr Discharge frequency: 13.56MHz Deposited film formation rate: 20Å/sec Discharge power: 0.18W/cm ² Each electrophotographic photoreceptor drum thus obtained was
It was installed on a Canon Inc. 400RE copying machine and printed on A-3 paper, and there were no white dot-like image defects (0.3 mm).
φ or more) was evaluated. This evaluation result is the first
Shown in the table. Furthermore, each of the electrophotographic photoreceptor drums of Examples 1 to 3 was further subjected to a durability test of 1 million sheets at 23°C/
Tests were conducted under conditions of 50% relative temperature, 30°C/90% relative humidity, and 5°C/20% relative temperature, but there was no increase in image defects, especially defects such as white spots, and the image showed good durability. It was confirmed that

[Table] [Effects of the present invention] According to the aluminum alloy of the present invention, Si
By optimizing the content and Vickers hardness, the workability of precision machining and the desired properties of processed products are dramatically improved, and the effects of inclusions are suppressed or completely eliminated, resulting in precision It is ideal for electrophotographic photoconductive members that require precision processing, and in particular, where accurate surface shapes due to precision processing are desired, since reduction in processability and deterioration of desired properties of processed products are suppressed. In addition, the tubular material obtained by drawing this aluminum alloy has an accurate surface shape, high dimensional accuracy, and high hardness, so it is particularly useful for forming precision tubular components such as supports for electrophotographic photoreceptor drums. It is suitable for Furthermore, the photoconductive member using the aluminum alloy as a support of the present invention has excellent uniformity and durability in electrical, optical, and photoconductive properties, and especially when used for electrophotography, the photoconductive member It is possible to obtain high-quality images with fewer defects.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an apparatus for manufacturing a photoconductive member using a glow discharge decomposition method. 1... Sediment tank, 2... Base plate, 3...
Tank wall, 4... Top plate, 5... Cathode electrode, 6... Drum-shaped support, 7... Raw material gas inflow valve, 8... Leak valve, 9... Exhaust valve, 10... Vacuum gauge, 11 ... Mass flow controller, 12 ... Heater, 13 ... High frequency power supply, 14 ... Motor.

Claims (1)

[Claims] 1 Contains 2% to 7% by weight of silicon, the remainder consists of aluminum and impurities, and the hydrogen as the impurity is per 100 grams of aluminum.
1.0cc or less, and iron as an impurity is
1. A precision-processed support for an electrophotographic photoconductive member, characterized in that it is manufactured from an alloy having a hardness of 2000 ppm or less and a Bitkers hardness of 50 Hv or more and 100 Hv or less.