JPH04242749A - Surface treatment method for electrophotographic photoconductor substrate - Google Patents

Abstract

PURPOSE:To provide a surface treatment method which has satisfactory washing property and capability of obtaining an electrophotographic photoconductor substrate with a surface having fewer image defects. CONSTITUTION:The surface of an electrophotographic photoconductor substrate 1 consisting of an aluminium material is cut by a bite 8 consisting of a polycrystalline diamond sintered body while supplying a water cutting solution thereto, and then, the substrate is washed with a washing solution consisting of a surfactant having a surface tension equal to less than 40dyne/cm.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for surface treating an electrophotographic photoreceptor substrate, and more particularly to a method for surface treating an electrophotographic photoreceptor substrate made of an aluminum-based material.

0002

[Prior Art] In electrophotographic copying machines, digital copiers, laser printers, etc., electrophotographic photoreceptors are formed by providing a photosensitive layer on a rotating drum-shaped electrophotographic photoreceptor substrate (hereinafter appropriately abbreviated as "substrate"). is widely used. As the material for the substrate constituting such an electrophotographic photoreceptor, aluminum-based materials are preferably used because of their advantages such as low cost, light weight, and ease of processing. This rotating drum-shaped base made of an aluminum-based material is generally finished by cutting the surface of a tubular material, and a cutting fluid is usually used during this cutting process. This cutting fluid is used for the purpose of cooling, lubricating, cleaning, etc., and specifically, petroleum-based, polybutene-based, kerosene, white kerosene, etc. are used. Furthermore, in order to prevent the occurrence of image defects, the surface of the substrate is also cleaned by a contact type cleaning means using a brush, an abrasive, etc. after cutting the substrate.

As specific techniques related to surface treatment methods for electrophotographic photoreceptor substrates, the following have been proposed. (1) Oiliness improver and/or extreme pressure additive 1.0
A technique for processing an electrophotographic photoreceptor substrate using a cutting oil containing less than % by weight (Japanese Patent Laid-Open No. 63-307463). (2) Technology for finishing the surface of an electrophotographic photoreceptor substrate made of an aluminum alloy containing magnesium, silicon, copper, and titanium in proportions in a specific range using a cutting tool with a rounded cutting part (Japanese Patent Laid-Open No. 64-86151) Publication No.). (3) Technology using an electrophotographic photoreceptor substrate made of an aluminum alloy containing silicon and iron in a specific range of proportions
(Japanese Unexamined Patent Application Publication No. 1986-86152). (4) A technique for finishing the surface of an electrophotographic photoreceptor substrate made of an aluminum alloy containing magnesium, silicon, and copper in proportions in a specific range using a cutting tool with a rounded cutting part (Japanese Patent Application Laid-Open No. 86153/1986) ). (5) Technology using an electrophotographic photoreceptor substrate made of an aluminum alloy containing silicon, magnesium, and iron in proportions within a specific range (Japanese Unexamined Patent Publication No. 86154/1986)
. (6) A technique using an electrophotographic photoreceptor substrate made of an aluminum alloy containing magnesium, silicon, copper, and titanium in proportions within a specific range (Japanese Patent Laid-Open No. 86155/1983). (7) silicon, iron, and magnesium in proportions within a specific range;
A technique using an electrophotographic photoreceptor substrate made of an aluminum alloy containing a specific proportion or less of other metals (Japanese Unexamined Patent Publication No. 1-123245). (8) Technology using a surface processing device that is composed of a lathe unit, a high-pressure liquid injection processing unit, and an electrophotographic photoreceptor substrate conveyance unit, and is capable of sequentially and automatically performing lathe processing and high-pressure injection processing. (Unexamined Japanese Patent Publication No. 1-172573). (9) Technology using a specific cutting fluid supply nozzle device having a spindle head that rotatably supports a spindle including a rotary tool with an oil hole and a rotary tool without an oil hole (Japanese Patent Laid-Open No. 62-152642) Public bulletin). (10) While spraying high-pressure water onto the surface of the electrophotographic photoreceptor substrate from the injection hole of a nozzle connected to a high-pressure water supply source, scan the nozzle along the surface of the substrate to A technique for roughening a surface to a predetermined surface roughness (Japanese Unexamined Patent Publication No. 63-264764). (11) After cutting the surface of an electrophotographic photoreceptor substrate made of an aluminum-based material with a diamond cutting tool while spraying cutting oil, the surface of the substrate is cleaned by contact cleaning means using a brush or abrasive. (Japanese Unexamined Patent Publications No. 2-201373 and No. 2-191963) which prevents the occurrence of image defects.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, aluminum cutting powder,
Environmental foreign substances such as dust and dirt, rust, etc. may be incorporated into the cutting oil and firmly adhere to the base. If this condition is left for a long period of time, for example one month or more,
Especially under high temperature and high humidity conditions in the summer, the above deposits become even more firmly attached, causing local corrosion (rust) to occur on the surface of the substrate, and this corrosion may not be visible to the naked eye. be.

[0005] Such corrosion can be caused by immersion in organic solvents or surfactant solutions, ultrasonic cleaning, ultraviolet rays/O3
It cannot be completely removed by non-contact cleaning means such as washing, and therefore, if an electrophotographic photoreceptor is constructed by providing a photosensitive layer on the surface of a substrate where such corrosion exists, image defects may occur in the corroded area. Particularly when applied to an image forming process employing a reversal development method, there is a problem in that black spots, black stripes, and local fogging occur in the resulting image.

[0006] Partial corrosion on the substrate surface can be removed to some extent by cleaning the substrate surface with contact cleaning means using a brush or abrasive, but depending on the aluminum material, corrosion may occur on the substrate surface. On the contrary, scratches occur, and the film thickness of the photosensitive layer, especially the carrier generation layer, formed on the scratched portion is likely to change, which changes the photosensitivity of the photosensitive layer, causing contrast in the halftone image, resulting in image defects. There is a problem. Furthermore, the surface roughness is 0.3 to 2.0 μmRmax, and the length is 0.3 to 2.0 μmRmax.
In a substrate made of an aluminum material that has 5 to 15 micro-roughnesses within 1 mm, oil, cutting powder, environmental foreign matter, etc. enter into the micro-roughness recesses, and if left unattended, they will stick. This fixed substance cannot necessarily be removed by using a brush or abrasive alone, and therefore causes image defects, which may prevent an electrophotographic photoreceptor substrate of good quality from being obtained.

[0007] Furthermore, in the case of a base made of an aluminum material whose surface has been processed using cutting oil as in the prior art,
To remove cutting oil sufficiently, Freon 11, 112
, 113 etc., trichlorethylene, 1,1,1
- Cleaning must be done using chlorinated solvents such as trichloroethane, perchlorethylene, methylene chloride, etc. Therefore, using large amounts of such solvents is prohibited from the viewpoint of ozone layer depletion, carcinogenicity, etc. There are problems with environmental pollution and work safety. Further, in the technique (10) above, the surface of the substrate is processed while jetting high-pressure water, and there is a problem in that it is difficult to uniformly process the metal surface using only high-pressure water.

The inventors of the present invention have conducted extensive research to solve the above problems, and have found that the occurrence of image defects is caused by the cutting powder, environmental foreign matter, etc. generated during surface processing of the substrate, using the cutting oil as a binder on the substrate surface. It was discovered that the cause of the problem was that the cutting oil itself was decomposed and firmly stuck, or that it was caused by a chemical reaction. Then, after cutting with a cutting tool made of polycrystalline diamond sintered body using water-based cutting fluid instead of cutting oil, cleaning with a surfactant aqueous solution with a surface tension of 40 dyne/cm or less removes fluorocarbons and chlorine-based The present invention was completed based on the discovery that it is possible to provide an electrophotographic photoreceptor substrate of excellent quality that can be easily cleaned without using a solvent and has fewer image defects.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a surface treatment method that can be easily cleaned without using fluorocarbons or chlorine-based solvents, and that can obtain an electrophotographic photoreceptor substrate with fewer image defects. It is in.

0010

[Means for Solving the Problems] The method for surface treatment of an electrophotographic photoreceptor substrate of the present invention includes supplying an aqueous cutting fluid to the surface of an electrophotographic photoreceptor substrate made of an aluminum-based material.
After cutting the surface of the base with a cutting tool made of a polycrystalline diamond sintered body, the surface tension is 40 dyne/
The method is characterized in that the surface of the substrate is cleaned with a cleaning liquid consisting of an aqueous surfactant solution having a thickness of 1 cm or less.

[0011]

[Operation] By using a water-based cutting fluid, welding and adhesion of environmental foreign substances such as aluminum cutting powder, dust, and dirt to the substrate surface can be effectively prevented. Even if deposits occur, they do not stick firmly, making subsequent cleaning easier, and the deposits can be satisfactorily cleaned with an aqueous surfactant solution having a surface tension below a specific value. Therefore, productivity is improved by reducing the number of cleaning steps, and there is less need for contact cleaning using a brush or abrasive, so there is less risk of scratches on the substrate surface. Moreover, since there is no need to use fluorocarbons or chlorinated solvents for cleaning, there are no environmental pollution or work safety problems. That is,
If you use Freon or chlorine solvent as a cleaning solution,
Water stains may remain on the substrate after cleaning, causing image defects, and chlorinated solvents, in particular, react with water and generate hydrochloric acid, causing pitting corrosion on the surface tension of the substrate made of aluminum-based materials. Although problems arise, these problems do not arise with the present invention. Further, the cost of the cutting fluid can be reduced, and since the water-based cutting fluid has a higher cooling effect than the oil-based cutting fluid, the life of the cutting tool can be extended.

0012

[Example] In the surface treatment method of the present invention, while supplying water-based cutting fluid to the surface of an electrophotographic photoreceptor substrate made of an aluminum-based material, the surface of the substrate is cut with a cutting tool made of a polycrystalline diamond sintered body. After processing, the surface of the substrate is cleaned with a cleaning liquid consisting of an aqueous surfactant solution having a surface tension of 40 dyne/cm or less.

[0013] As aluminum-based materials, A1070, A1100, A3003, and
A5005, A5805, A6063, etc. are used. The shape of the base body is not particularly limited, and may be either a rotating drum shape or an endless seat belt shape.

A water-based cutting fluid is used as the cutting fluid, and it is preferable to supply the water-based cutting fluid to the substrate surface in the form of a mist using, for example, "Magic Cut" manufactured by Fuso Seiki Co., Ltd. By making it into a mist, it effectively prevents cutting dust and environmental foreign matter generated during cutting from sticking firmly to the substrate surface, and even if cutting dust etc. gets into the micro-roughness of the recesses, it is easily removed. . Furthermore, since cutting powder and the like do not firmly adhere to the surface of the substrate, cleaning becomes easy. Also,
Even if left unused for a long period of time, there is no risk of cutting dust or environmental foreign matter firmly adhering to the base surface. Furthermore, during surface processing,
Since a uniform and strong oxide film is formed on the surface of the base made of aluminum-based material by the aqueous cutting fluid in the form of a mist, the surface condition of the base is stable and there is no risk of local corrosion.

[0015] The supply amount of water-based cutting fluid has a good cooling effect,
From the viewpoint of obtaining lubricating and cleaning effects, 0.003ml
/cm2 or more is preferable. Specific examples of aqueous cutting fluids include pure water, tap water, aqueous solutions of anionic, cationic, nonionic, and amphoteric surfactants, water-soluble organic solvents such as alcoholic and ketone solvents, and combinations of these and water. Examples include mixtures of the following.

In the present invention, a cutting tool made of a polycrystalline diamond sintered body is used as the cutting tool. For rough machining, a normal polycrystalline diamond sintered body is used, but for finishing machining, a polycrystalline diamond sintered body with a grain size of approximately 0.5 μm and a nose radius R of 20 mm or more is used. It is preferable to use a bite. By using a nose with a large radius R, the maximum height Rmax within the feed pitch of the cutting tool can be increased.
becomes smaller and the machined surface becomes easier to clean. That is, the shape has a small maximum height Rmax and a large pitch. Furthermore, by increasing the radius R of the roundness of the nose, the feeding pitch of the cutting tool can be increased when the maximum height Rmax is the same, which is also effective for takt time. Here, the maximum height Rmax is JIS B0601
-1982. The measuring instrument used was the "Surface Roughness Meter SE-30H" (manufactured by Kosaka Laboratory), which is a stylus-type surface roughness measuring instrument specified in JIS B0651. The nominal value is 2 μm.

[0017] The conditions for surface machining are that for rough machining, the spindle rotation speed is 2000 to 6000 rpm, and the depth of cut is 0.
．． 1 to 0.2 mm, feed pitch 0.2 mm/re
v The degree of rotation is good, and in finishing machining, the spindle rotation speed is 200
The preferred speed is 0 to 6000 rpm, the depth of cut is 20 μm, and the feed pitch is about 0.2 mm/rev. Note that the main shaft rotation speed cannot be unconditionally defined because it also differs depending on the outer diameter of the tubular base body.

In the present invention, it is particularly preferable to perform cutting so that the surface roughness of the substrate is 0.3 to 1.0 μmRmax. In addition, on the surface of the base, there are 5 to 40 micro-roughnesses due to the grain size of the polycrystalline diamond sintered body that constitutes the tool per rotation length (feed pitch) in the feeding direction of the tool. It is preferable to perform the cutting process so as to Here, the microroughness is
It was measured in the same way as the measurement of the maximum height Rmax above, and the fineness of the microroughness that can be measured varies depending on the radius of curvature of the tip of the stylus used, but in one example, the radius of curvature of the tip A stylus with a nominal value of 2 μm is used.

The machine tool that can be used for cutting the base is not particularly limited, but includes, for example, a lathe for machining the base as shown in FIG. 1. In FIG. 1, 1 is a drum-shaped base, 2 is a magnet base, 3 is a holder, 4 is an atomizer, 5 is a spray nozzle, 6 is a cutting fluid container, 7 is an operating air valve, and 8 is a cutting tool. When the operator steps on the operation air valve 7 with his foot, air is sent to the atomizer 4, and a mist of water-based cutting fluid is sprayed from the spray nozzle 5 of the cutting fluid container 6 onto the contact area between the cutting tool 8 and the base 1. be done. A specific example of a cutting fluid spraying device is "Magic Cut" (manufactured by Fuso Seiki Co., Ltd.). FIG. 2 is an enlarged view of the cutting fluid spraying device.

The cut substrate is then subjected to a cleaning process, but in the present invention, the surface tension is 40 dyne.
The surface of the substrate is cleaned with a cleaning liquid consisting of an aqueous surfactant solution of /cm or less. According to the cleaning method using an aqueous surfactant solution, there are no environmental hygiene problems that occur when using fluorocarbons or chlorinated solvents, and there is also the problem of image defects when scrubbing strongly with a brush or abrasive. does not occur either. In particular, when fluorocarbons or chlorine-based solvents are used as the cleaning solution, water stains may remain on the substrate after cleaning, causing image defects.In particular, chlorine-based solvents may react with water and generate hydrochloric acid. However, the problem of pitting corrosion occurring due to the surface tension of a substrate made of an aluminum-based material occurs, but these problems do not occur in the present invention.

Examples of the surfactant include anionic surfactants such as higher alkyl sulfonates, higher alcohol sulfate ester salts, phosphate ester salts, and carboxylate salts, benzalkonium chloride, sabamin type quaternary ammonium salts, Examples include cationic surfactants such as pyridinium salts and amine salts, amphoteric surfactants such as amino acid and betaine types, and nonionic surfactants such as polyethylene glycol and polyhydric alcohol types. These may be mixed and used as appropriate.

The surface tension of the surfactant aqueous solution is 40dy
It is necessary that it be below ne/cm. An aqueous surfactant solution with a low surface tension exhibits excellent cleaning properties because of its low surface activity. Here, "surface tension" is measured by "Wilhelmy surface tension meter A-3 model" manufactured by Kyowa Kagakusha (using platinum plate, 25° C.).

[0023] Although the cleaning method is not particularly limited,
Specifically, the following methods may be mentioned. (1) A method of ultrasonically cleaning a substrate by immersing it in an aqueous surfactant solution. (2) A means of dipping the substrate in an aqueous surfactant solution and lightly rubbing the surface of the substrate with a sponge or brush. (3) Means of immersion in a surfactant aqueous solution. The above cleaning means may be used in combination as appropriate. After washing with an aqueous surfactant solution, a drying step is performed, but the drying means is not particularly limited. For example, warm pure water pulling drying, isopropanol drying, steam drying, etc. are used.

The electrophotographic photoreceptor substrate surface-treated by the method of the present invention is used to construct electrophotographic photoreceptors used in electrophotographic copying machines, digital copiers, laser printers, etc. The photoreceptor is constructed by, for example, providing an organic photosensitive layer including a carrier generation layer and a carrier transport layer on the surface of the substrate.

More specific examples will be described below, but the present invention is not limited to these examples. Example 1 The surface of a substrate was cut using a cutting tool while supplying cutting fluid to the surface of the substrate according to the following conditions. (1) Base: A base made of an aluminum-based material, with an outer diameter of 60 mm.
Kobe Steel's A40S (mm) with a length of 273 mm.
6000 series) was used. In addition to aluminum, this A40S also contains 0.55% by weight of magnesium, 0.12% by weight of silicon, 0.05% by weight of iron, 0.01% by weight of titanium, and 0% by weight of zinc.
．． 0.01% by weight, and manganese in a proportion of 0.01% by weight or less. (2) Tap water with a cutting fluid specific resistance of 5 kΩ/cm was used. (3) Cutting fluid was supplied at a supply amount of 0.003 ml/cm2. (4) A base processing lathe shown in FIG. 1 was used, which was equipped with "Magic Cut" (manufactured by Fuso Seiki Co., Ltd.) as a machine tool cutting fluid spraying device. (5) For rough machining with a cutting tool, a cutting tool made of a polycrystalline diamond sintered body with a nose radius of 3 mm and a grain size of 5 μm was used. In the finishing process, a cutting tool made of a polycrystalline diamond sintered body with a nose radius of 20 mm and a grain size of 0.5 μm was used. (6) Machining conditions In rough machining, the spindle rotation speed was 3000 rpm, the feed pitch was 0.2 mm/rev, and the depth of cut was 0.2 mm. In finishing machining, the spindle rotation speed is 3000 rpm,
Feed pitch: 0.2mm/rev, depth of cut: 20μm
And so. The substrate surface cut in the above manner is
An electrophotographic photoreceptor substrate was obtained which was washed and surface-treated as described below. The surface roughness of this base is 2.50μmR
max, and the number of microroughnesses per feeding pitch in the feeding direction of the cutting tool was 20. (1) The surface tension as a surfactant aqueous solution is 28 dyne.
Ultrasonic cleaning (frequency: 28 kHz) was performed using an ultrasonic cleaning device (600 W) manufactured by Sonic Fellows using an aqueous solution of sodium lauryl sulfate of /cm. (2) Next, ultrasonic cleaning (frequency 200 kHz) was performed using pure water using the ultrasonic cleaning device described above. (3) After that, the substrate was immersed in pure water. (4) Furthermore, using a heated pure water pulling device manufactured by Sonic Fellows, the pulling speed was 15 mm/min and the temperature was 60°C.
Drying was carried out using warm pure water under these conditions.

Examples 2 to 5 Surface-treated electrophotographic photoreceptor substrates were obtained in the same manner as in Example 1, except that the conditions shown in Table 1 below were used. however,
A to E and a to e listed in the cleaning liquid column of Table 1 represent the following. A: Aqueous solution B of sodium lauryl sulfate (surfactant)
: Aqueous solution C of Sapamin MS (cationic surfactant, manufactured by Ciba): 15 mol adduct of ethylene oxide stearate (
D: Aqueous solution of stearyl dimethyl betaine (surfactant) E: Aqueous solution of RBS48S (a mixture of surfactant and inorganic substance, manufactured by Junsei Kagaku Co., Ltd.) A: Aqueous solution of sodium lauryl sulfate (surfactant) (
(low concentration) b: Aqueous solution (low concentration) of Sapamin MS (positive ionic surfactant, manufactured by Ciba) c: 15 mol adduct of ethylene oxide stearate (
(surfactant) aqueous solution (low concentration) d: Aqueous solution (low concentration) of stearyl dimethyl betaine (surfactant) e: Aqueous solution (low concentration) of RBS48S (a mixture of surfactant and inorganic substance, manufactured by Junsei Kagaku Co., Ltd.)

Comparative Examples 1 to 15 Example 1 except that the conditions shown in Tables 1 and 2 below were used.
An electrophotographic photoreceptor substrate surface-treated in the same manner as above was obtained. "D 110" listed in the cutting fluid column of Table 2 contains 54% paraffinic hydrocarbons and 46% naphthenic hydrocarbons.
This is a water-insoluble cutting fluid containing %.

[0028]

[Table 1]

[0029]

[Table 2]

Actual evaluation Using the electrophotographic photoreceptor substrates obtained in the above Examples and Comparative Examples, a subbing layer, a carrier generation layer, and a carrier transport layer were sequentially laminated in the following manner to achieve functional separation. An electrophotographic photoreceptor having a two-layer organic photoreceptor layer was produced.

(1) Toluene and 2-butanone (MEK) as undercoat layer coating solvents
A subbing layer having a dry film thickness of 0.2 μm was provided on the electrophotographic photoreceptor substrate using LVAX 4260 (ethylene copolymer) as a binder.

(2) 2-butanone (MEK) was used as the carrier generation layer coating solvent, and KR-5240 (silicone resin) was used as the binder (solution).
Using τ-type metal-free phthalocyanine as a carrier generating substance, the amount of adhesion after drying was 4 m on the undercoat layer.
A carrier generation layer of g/dm2 was provided.

(3) Carrier transport layer: 1,2-dichloroethane was used as the coating solvent, Iupilon Z-200 (polycarbonate BPZ) was used as the binder, and ED-485 was used as the carrier transport material.
(styryltriphenylamine type), Irganox-1010 (pentaerythryl-tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) as an antioxidant, silicone Using KF-54 (1/10 dilution) as oil, a carrier transport layer having a dry film thickness of 20 μm was provided on the carrier generation layer.

Each of the electrophotographic photoreceptors described above was mounted on a laser printer "LP3115" manufactured by Konica Corp., and an actual photographic test was conducted in which an image was formed on A4 size plain paper using a reversal development method, and the image quality was evaluated. In addition, the charging voltage is black dot,
VH = 45 to prevent black stripes and local fogging.
It was set to 0V. In addition, the image quality is evaluated as ◎ when there are no black spots, black stripes, or local fog, and ○ when there are some black spots but no fog.
The case where fogging occurred was marked as ×. The above results are also shown in Tables 1 and 2.

[0035]

[Effects of the Invention] As explained in detail above, according to the surface treatment method of the present invention, water-based cutting fluid is used in the cutting process, so that environmental foreign substances such as aluminum cutting powder, dust, and dirt are removed from the substrate surface. Welding and sticking are effectively prevented,
In the cleaning process, an aqueous surfactant solution with a surface tension of 40 dyne/cm or less is used as the cleaning solution, which not only provides good cleaning performance but also reduces environmental pollution, work safety, and pores caused by the use of fluorocarbons and chlorinated solvents. It is possible to obtain an electrophotographic photoreceptor substrate that does not cause corrosion problems and has fewer image defects such as black spots, black streaks, dark spots, and localized fog.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a base processing lathe.

FIG. 2 is an enlarged perspective view of a cutting fluid spraying device.

[Explanation of symbols]

1 Base 2 Magnet base 3 Holder 4 Atomizer 5 Spray nozzle 6 Cutting fluid container 7 Operation air valve 8 bytes

Claims (1)

[Claims] 1. After cutting the surface of an electrophotographic photoreceptor substrate made of an aluminum-based material with a cutting tool made of a polycrystalline diamond sintered body while supplying an aqueous cutting fluid to the surface of the substrate, the surface tension of the substrate is 40 dyne. 1. A method for surface treatment of an electrophotographic photoreceptor substrate, characterized in that the surface of the substrate is cleaned with a cleaning liquid consisting of an aqueous surfactant solution of /cm or less.