JP2975537B2 - Aluminum substrate for photoconductor in electrophotographic apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum substrate for a photosensitive member as a conductive support for supporting a photosensitive layer in an electrophotographic apparatus such as a copying machine, a facsimile, a printer and the like.

[0002] In this specification, the term aluminum is used to include both aluminum and its alloys.

[0003]

2. Description of the Related Art In general, a photoreceptor in an electrophotographic apparatus is constituted by a conductive substrate made of aluminum and a photosensitive layer is coated. As the photosensitive layer, an inorganic material such as selenium is used. Organic photoconductors (so-called OPC photoconductors) using organic materials instead of system photoconductive materials have come to be used because of their excellent film-forming properties, light weight, and low cost. I have.

Recently, in order to further improve the performance and characteristics of the organic photoreceptor, a charge generating layer (C
GL) and a charge transport layer (CTL) are sequentially applied to provide an organic photoreceptor called a laminate type. in this case,
For the purpose of improving coating properties and blocking properties of the photosensitive layer, an anodic oxide film may be formed on the surface of the aluminum substrate, and the photosensitive layer may be coated on the film.

Conventionally, in an electrophotographic apparatus incorporating an organic photoreceptor having an anodized film as described above, a laser, particularly a semiconductor laser, is used as a light source for writing an electrostatic latent image on the surface of the photoreceptor. Is generally used, and the surface of the photoreceptor is scanned by reflecting this laser light with a polygon mirror or the like. However, since the laser light is monochromatic light (wavelength is about 780 nm) and the incident angle changes, interference fringes are generated due to a path difference caused by the reflection of the laser light on the photoreceptor surface and the reflection on the aluminum substrate surface. And this causes an image defect.

Therefore, attempts have been made to use a light emitting diode instead of a laser as a light source. Since such a light emitting diode has a wide wavelength distribution, the occurrence of interference fringes can be suppressed.

However, in this case, it has been found that a new problem that small black spot noise occurs in a solid white image or white spots or white stripes may occur in a solid black image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and has a small black spot noise in a solid white image when a light emitting diode is used as a light source, a white spot in a solid black image, and the like. The purpose is to prevent the occurrence of white streaks.

[0009]

In order to achieve the above object, the present inventor has determined that the cause of the occurrence of small black spot noise in a solid white image and the cause of white spots or white stripes in a solid black image are anodic oxidation. The inventors have found that the present invention is involved in the surface roughness of the film, and have completed the present invention.

That is, the present invention relates to an aluminum substrate for a photoreceptor in an electrophotographic apparatus in which a light emitting diode is used as a light source, the surface of which is coated with an anodic oxide film, and the surface roughness of the anodic oxide film is reduced. Rmax 1.
An aluminum substrate for a photoreceptor in an electrophotographic apparatus, characterized in that the thickness is specified to be 0 μm or less.

In the present invention, the light emitting diode is used as the light source because the light emitting diode has a wide wavelength distribution, so that the occurrence of interference fringes can be suppressed.
The type of the light emitting diode is not particularly limited, and a red light emitting diode, a green light emitting diode, or the like can be used as appropriate. Preferably, the wavelength λ = 660 ±
A red light emitting diode having a wavelength of 20 nm or a wavelength λ = 710 ± 20 nm can be used.

The surface roughness of the anodic oxide film formed on the surface of the aluminum substrate is Rmax (maximum height) of 1.0 μm.
m is defined as having a surface roughness of Rmax 1.0 μm
This is because, when the value exceeds, small black point noise in a white solid image, white spots and white streaks in a black solid image are likely to occur. It is presumed that small black spot noise is likely to occur in solid white images because the surface is so rough that dirt easily adheres to the surface, or the adhered dirt becomes difficult to remove by washing. Is done. Also, the reason why white streaks easily occur in a black solid image is that the surface of the anodic oxide film has an Rmax of 1.0.
When the thickness exceeds μm, the photosensitive agent may be accumulated or the coating film may be cut off during the coating process of the photosensitive layer, and as a result, image defects such as white spots and white stripes on a solid black image may easily occur. It is presumed. Particularly preferably, the surface roughness of the anodic oxide film is set to Rmax 0.6 μm or less.

In the present invention, the means for regulating the surface roughness of the anodic oxide film to Rmax 1.0 μm or less is not particularly limited, but the following method is mentioned as the most reliable means. it can. That is, according to the research of the inventor, the surface roughness of the anodic oxide film depends on the surface roughness of the aluminum substrate and changes with the relationship with the composition component of the aluminum substrate, particularly on the amount of Cu. I understood. It is desirable that the surface roughness of the aluminum substrate be specified in a mirror surface state of RZ (ten-point average roughness) of 0.8 μm or less. On the other hand, the surface roughness of the aluminum base is RZ
Cu of 0.8 μm or less in aluminum substrate
If the amount exceeds 0.05% by weight, there is a risk that a large defect locally occurs on the surface of the anodic oxide film, and it becomes difficult to regulate the surface roughness of the anodic oxide film to Rmax 1.0 μm or less. . Therefore, it is desirable that the surface roughness of the aluminum substrate be set to Rz 0.8 μm or less and the Cu content in the aluminum substrate be specified to 0.05 wt% or less. Particularly preferred surface roughness of the aluminum substrate is RZ.
It is 0.5 μm or less. On the other hand, C in the particularly preferred base
The amount of u is 0.03 wt% or less. In addition, composition components other than the Cu amount are not limited.

The method for making the aluminum substrate have such a surface roughness as described above is not particularly limited, and it may be mirror-finished by cutting, or the photosensitive member is a photosensitive drum and the aluminum substrate is an aluminum tube. If it is provided as, the aluminum tube obtained by extrusion or drawing is ironed or drawn,
If necessary, it may be realized by cutting afterwards.

The type of the anodic oxide film is not particularly limited, but a sulfuric acid film is generally employed.
The thickness of the anodic oxide film is preferably 3 to 10 μm.
The conditions for the anodizing treatment are not particularly limited, and conditions conventionally used may be adopted.

Incidentally, in order to further suppress the occurrence of interference fringes in addition to the suppression of image defects by regulating the surface roughness of the anodic oxide film, preferably, as shown schematically in FIG.
A plurality of light emitting diodes (1) are used, these light emitting diodes (1) are arranged in parallel with the photoconductor (2) at the same interval, and a light emitting diode (1) and the photoconductor (2) It is preferable that a lens (3) is disposed on the photoconductor (2) so that light from the light emitting diode (1) is vertically incident on the photoconductor (2). As a result, a path difference due to reflection on the surface of the photoconductor (2) and reflection on the surface of the aluminum substrate (2a) is reduced, and interference fringes are further suppressed. FIG.
(2b) is a photosensitive layer, and (2c) is an anodized film.
In addition, as the lens (3) as described above, a multi-lens such as a SELVOC lens can be used.

As the photosensitive layer applied to the surface of the aluminum substrate via the anodic oxide film, a layer made of an organic material is generally used, and a laminated photosensitive layer having a charge generating layer and a charge transport layer is preferably used. Is formed. As the material of the laminated photosensitive layer, a conventionally known material may be appropriately used. For example, as the photoconductor used for the charge generation layer, various organic pigments such as phthalocyanine, azo, quinacridone, polycyclic quinone, perylene, indigo, and benzimidazole can be used. Above all,
Metals such as metal-free phthalocyanine, copper, indium chloride, gallium chloride, tin, oxytitanium, zinc, and vanadium, or oxides thereof, and azo pigments such as chloride-coordinated phthalocyanines, monoazo, bisazo, trisazo, and polyazos Is preferred.

The charge generation layer is formed as a uniform layer of these substances or in a state where fine particles are dispersed in a binder. Examples of the binder resin used herein include polyvinyl butyral, phenoxy resin, epoxy resin, polyester resin, acrylic resin, methacrylic resin, polyvinyl acetate, polyvinyl chloride, methyl cellulose, and polycarbonate.
Carbonate resins and the like. Preferably, the photoconductor is contained in an amount of 20 to 300 parts by weight, particularly 30 to 150 parts by weight, based on 100 parts by weight of the binder resin.
The thickness of such a charge generation layer is usually 5 μm or less, preferably 0.01 to 1 μm.

As the charge transporting material used in the charge transporting layer, polyvinyl carbazole, polyvinyl pyrene,
High molecular compounds such as polyacenaphthylene or low molecular compounds such as various pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, butadiene derivatives and stilbene derivatives can be used. A binder resin is blended with these charge transporting materials as needed.

Preferred binder resins include vinyl polymers such as polymethyl methacrylate, polystyrene and polyvinyl chloride and copolymers thereof, and polycarbonate resins.
, Polyester, polysulfone, phenoxy resin, epoxy resin, silicone resin, and the like. These partially crosslinked cured products are also used. It is preferable that the charge transport material is contained in an amount of 30 to 200 parts by weight, particularly 50 to 150 parts by weight, per 100 parts by weight of the binder resin.

The charge transport layer may contain various additives such as an antioxidant and a sensitizer, if necessary.

The thickness of the charge transport layer is usually 10 to 40 μm,
Preferably, it is used in a thickness of 10 to 25 μm.

[0023]

An anodic oxide film is formed on the surface of the aluminum substrate, and the surface roughness of the anodic oxide film is Rma.
Since x is defined to be 1.0 μm or less, the occurrence of small black spots in a solid white image, white spots and white streaks in a solid black image is suppressed. Further, since a light emitting diode is used as a light source, the occurrence of interference fringes is suppressed, and a high-quality image can be provided.

The surface roughness of the aluminum substrate is Rz
When the Cu content in the aluminum base is specified to be 0.05 wt% or less and the surface roughness of the anodic oxide film is set to Rmax 1.0 μm or less.
m or less, the surface roughness of the anodic oxide film is reliably reduced to Rmax 1.0 μm without the need for surface treatment.
It can be:

Further, a plurality of light emitting diodes are arranged in parallel at the same interval with respect to the photosensitive member, and light from the light emitting diode is vertically incident on the photosensitive member between the light emitting diode and the photosensitive member. When a lens is provided, a path difference due to reflection on the photoreceptor surface and reflection on the aluminum substrate surface can be reduced, and interference fringes can be suppressed.

[0026]

EXAMPLE As shown in Table 1, a plurality of aluminum extruded pipes based on A3003Al alloy and A6063Al alloy and having a regulated amount of Cu at various values were prepared as shown in Table 1. Then, the surface of the aluminum extruded tube was mirror-polished to obtain various surface roughnesses Rz shown in Table 1.
Was made.

Next, each aluminum substrate was subjected to anodizing treatment by a sulfuric acid method to form an anodized film having a film thickness of about 7 μm. Table 1 shows the surface roughness of the anodic oxide film of each sample.

Next, a photosensitive layer having a charge generating layer and a charge transporting layer was formed on the surface of each anodic oxide film as follows. That is, CGL is obtained by diluting metal-free phthalocyanine to 4% with tetrahydrofuran and forming a film having a thickness of about 0.5%.
The coating was applied to a thickness of μm and dried. Next, CT
The agent (hydrazone compound) and CT resin (polycarbonate) were dissolved in methylene chloride at a ratio of 1: 2, applied to a thickness of about 20 μm, and dried to obtain CTL.

With respect to the various photoconductors obtained above, FIG.
As shown in the figure, a plurality of light emitting diodes (1) as an exposure light source for forming an electrostatic latent image are placed 4.7 m from the surface of the photosensitive layer (2b) via a cell box lens (3) in the middle.
The photoconductors (2) were arranged in a line in parallel with each other at a distance of m. For the light emitting diode (1), the wavelength λ
= 710 ± 20 nm red light emitting diode was used. The incident angles of the light from the light emitting diodes to the photoconductor (2) were all within ± 1 degree.

Then, this was mounted on a printer, a halftone image was produced by a dot pattern, and the presence or absence of interference fringes was examined. The presence or absence of small black dots by a solid white image and the presence of white stripes by a solid black image were also examined. Table 1 shows the results.

[0031]

[Table 1] As can be seen from the results in Table 1 above, the products of the present invention in which the surface roughness of the anodic oxide film is Rmax 1.0 μm or less can suppress white streaks and small black spots as compared with comparative products out of the range. I was able to confirm that. In particular, it can be seen that excellent image characteristics can be exhibited by setting the surface roughness of the anodic oxide film to Rmax 0.6 μm or less. Also, by defining the surface roughness Rz of the aluminum base to be 0.8 μm or less and the Cu content of the aluminum base to be 0.05 wt% or less, the surface roughness of the anodic oxide film can be made to be 1.0 μm or less. Recognize.

[0032]

According to the present invention, an anodic oxide film is formed on the surface of an aluminum substrate,
Since the surface roughness of the anodic oxide film is defined to be Rmax 1.0 μm or less, it is possible to suppress the occurrence of small black spots in a solid white image, white spots and white streaks in a solid black image. Of course,
Since a light emitting diode is used as a light source, the occurrence of interference fringes can be suppressed, and a high-quality image free from image defects can be provided.

Also, the surface roughness of the aluminum substrate is Rz
When the Cu content in the aluminum base is specified to be 0.05 wt% or less and the surface roughness of the anodic oxide film is set to Rmax 1.0 μm or less.
m or less, the surface roughness of the anodic oxide film is reliably reduced to Rmax 1.0 μm without the need for surface treatment.
It can be:

A plurality of light emitting diodes are arranged in parallel with the photosensitive member at the same interval, and light from the light emitting diode is vertically incident on the photosensitive member between the light emitting diode and the photosensitive member. If the lens is arranged, the path difference due to reflection on the photoreceptor surface and reflection on the aluminum substrate surface can be reduced, interference fringes can be suppressed, small black spots in a solid white image, An even better image can be provided in combination with the prevention of the occurrence of white spots and white stripes in a solid black image.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light emitting diode 2 ... Photoconductor 2a ... Aluminum base 2b ... Photosensitive layer 2c ... Anodized film 3 ... Lens

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomio Yoneyama 1014 Miyaharacho, Kofu City, Yamanashi Prefecture Inside Yamanashi Electronics Industry Co., Ltd. (72) Inventor Masaaki Oide 6, 224 Kaiyamacho Sakai City Showa Aluminum Co., Ltd. (56) References JP-A-4-208942 (JP, A) JP-A-4-265979 (JP, A) JP-A-5-80565 (JP, A) JP-A-4-269760 (JP, A) JP-A-4-29253 (JP, A) JP-A-3-259267 (JP, A) JP-A-5-80568 (JP, A) JP-A-3-236060 (JP, A) (58) Int.Cl. ⁶ , DB name) G03G 5/14 101 G03G 5/10

Claims (3)

(57) [Claims] 1. An aluminum substrate for a photoreceptor in an electrophotographic apparatus using a light emitting diode as a light source, the surface of which is coated with an anodic oxide film, and the anodic oxide film has a surface roughness of Rmax 1.0 μm. An aluminum substrate for a photoreceptor in an electrophotographic apparatus, which is defined as follows. 2. An aluminum substrate having a surface roughness of Rz 0.
2. The electronic device according to claim 1, wherein the surface roughness of the anodic oxide film is 1.0 μm or less by defining the Cu content in the aluminum substrate to be 0.05 wt% or less while being specified to be 8 μm or less. Aluminum base for photoconductors in photographic equipment. 3. An electrophotographic apparatus, comprising: a plurality of light emitting diodes arranged in parallel with a photoconductor at an equal interval; and a light from the light emitting diode being supplied between the light emitting diode and the photoconductor. 3. An aluminum substrate for a photoreceptor in an electrophotographic apparatus according to claim 1, wherein a lens for vertically incident on the substrate is arranged.