JP2000162790A - Image forming device and electrophotographic photoreceptor used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor using the method for surely preventing moire without largely roughening the surface of base substance, and to provide an image forming device extremely reduced in the occurrence of moire by applying the photoreceptor. SOLUTION: In this image forming device, the electrophotographic photoreceptor 1 provided with a photoreceptive layer on a conductive layer, is used, and a latent image is formed by dot exposure where an exposure incident angle is 3 to 20 deg.. The dispersion of reflected light according to positions in the regular reflection direction of the photoreceptor 1 is 30 to 70% and a distance between the minium and the maximum of the dispersion is >=100 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus used as a copying machine, a printer or the like, and more particularly to an electrophotographic photosensitive member for dot exposure used therein.

[0002]

2. Description of the Related Art Conventionally, a photoreceptor, particularly a photoreceptor subjected to image exposure using coherent light, has a problem in that moire fringes are generated and image quality is impaired. 2. Description of the Related Art In recent years, an image forming apparatus that performs image exposure using a laser light source and visualizes the image by an electrophotographic method has become mainstream in a general copying machine and printer. This is because this combination can print out digital image information with high speed and high image quality, and is also suitable for outputting image information after processing.

In an electrophotographic photosensitive member, incident light is immediately absorbed by the photosensitive layer (a charge generation layer in the case of a multilayer structure), and once passes through the photosensitive layer and is reflected at the interface with the conductive layer. Some are absorbed by the photosensitive layer through various paths, such as those that are reflected and then absorbed on the surface of the photosensitive layer, and the light interferes with each other to cause exposure unevenness. This is because the amount of light absorbed by the photosensitive layer (charge generation layer) locally varies due to the interference of the light, and when developed, the density becomes uneven.

Conventionally, as a countermeasure, the interface between the photosensitive layer and the layer below it, that is, when a conductive substrate such as an aluminum drum is used, its surface is roughened, or the metal is vapor-deposited on a PET base or the like. When a conductive layer is formed separately, the surface of the conductive layer is roughened to prevent interference and to solve the problem.

[0005] However, such a method for roughening alone can certainly prevent moiré when the surface roughness is increased, but in some cases the image quality is rather deteriorated because the resolution and the like are deteriorated. Often it did not. Further, a belt-shaped photoreceptor or the like has a problem of mechanical strength, so that the surface of the substrate cannot be roughened too much.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to find a method for reliably preventing moiré without roughening the surface of a substrate, and to apply the method to an electrophotographic photosensitive member.
It is another object of the present invention to provide an image forming apparatus in which moire is extremely reduced.

[0007]

The object of the present invention is achieved by adopting the following constitution.

[1] In an image forming apparatus using an electrophotographic photosensitive member having a photosensitive layer provided on a conductive layer and forming a latent image by dot exposure at an exposure incident angle of 3 to 20 degrees, the regular reflection direction of the photosensitive member Is 30 to 70% depending on the position of the amount of reflected light, and the interval between the local minimum and maximum of the variation is 1
An image forming apparatus having a thickness of at least 00 μm.

[2] The image forming apparatus according to [1], wherein a laser beam is used as a light source for dot exposure.

[3] The electrophotographic photoreceptor for use in the image forming apparatus according to [1], wherein the electrophotographic photoreceptor has a multilayered photosensitive layer comprising at least a charge generation layer and a charge transport layer on the conductive layer. Photoconductor.

In the present invention, an electrophotographic photoreceptor having a photosensitive layer provided on a conductive layer refers to an electrophotographic photoreceptor having a photosensitive layer provided on an aluminum drum substrate (also referred to as a support) which is commonly used. Included in In this case, the conductive layer also serves as the drum base itself, and thus need not be particularly provided. However, when a belt-shaped photoreceptor is used using a flexible substrate, which is a preferred embodiment of the present invention, the support is usually insulative in many cases, and a conductive layer is generally applied separately. It is a target.

The conductive layer may be formed by vapor deposition or sputtering of a metal or metal oxide such as aluminum or ITO (indium tin oxide), or by mixing ITO or alumina conductive fine particles with a resin. And a resin having a coating film formed thereon.

As the material for the photoreceptor support that can be used in the present invention, generally known engineering plastic bases can be used. For example, polyethylene terephthalate, polyethylene naphthalate, polyetherimide, polyether sulfone, Examples thereof include polycarbonate and polyarylate, but are not limited to those shown here. The thickness of the belt-like support is 50 to 100 μm for the purpose of balancing rigidity and flexibility.
m are often used.

In any case, the surface of the support in the present invention is preferably subjected to a surface roughening treatment by any method. In the present invention, it is particularly preferable that Rz on both the front and back surfaces of the belt-shaped support is 0.4 to 5 μm. Rz is the difference between the average height of the five peaks and the average height of the five valleys between the lengths L (250 μm in the present invention).

The Rz is an optical stylus type pickup E-D
It can be measured by an optical stylus type surface roughness measuring device Sircom 470A (manufactured by Tokyo Seimitsu Co., Ltd.) incorporating T-SL024.

As the method for roughening the support, any generally known method may be employed. For example, fine particles such as a metal oxide such as titanium oxide or an organic substance are kneaded into a base to form a film. Stretched ones can be mentioned. Here, the shape of the fine particles kneaded into the base may be a true sphere or an irregular shape, and may be colorless and transparent, or colored such as white or yellow. Further, the size of the fine particles is preferably about 0.1 to 3 μm.

In addition, as a method of roughening the support, it is also effective to make the surface of the support uneven by sandblasting.

By using the electrophotographic photosensitive member having a photosensitive layer on the belt-like support of the present invention, high durability can be obtained even in an image forming apparatus having a mechanism in which at least one of the belt stretching rollers abuts on the photosensitive layer surface. Can be obtained. In this case, at least one of the belt tension rollers has a diameter of 15 mm.
A small-diameter roller having a diameter of from 40 mm to 40 mm can also be used.

Furthermore, since moire is not generated by laser light exposure and an extremely small image forming apparatus can be provided, an electrostatic latent image formed by writing on a photosensitive member by laser light is developed. Also, the present invention can be preferably applied to an image forming apparatus that employs a method in which a multicolor superimposed toner image is formed on a photoconductor and then transferred collectively.

In the case of laser beam exposure, the angle of incidence of light is not perpendicular to the surface of the photoreceptor, but is inclined at 3 to 20 degrees. This is because the reflected light on the photoconductor surface etc.
This is a measure to reduce the degree of re-irradiation to the photoreceptor which overlaps with the exposure light and adversely affects the photoreceptor.

In the present invention, furthermore, the variation depending on the position of the amount of reflected light in the specular reflection direction is 30 to 70%, and the minimum and maximum interval of the variation is set to 100 μm or more, so that the surface of the substrate is not excessively roughened. We found a way to reliably prevent moiré.

FIGS. 6 and 7 are diagrams for explaining the method of measuring the variation of the amount of reflected light depending on the position and the interval between the local minimum and the maximum of the variation and the measurement results.

Here, the measurement of the variation depending on the position of the amount of reflected light is performed as follows.

An ultra-high-precision laser displacement meter LC2400 manufactured by Keyence Corporation and a sensor head LC242 for regular reflection measurement
0 is used. The photoconductor sample was placed at a position (10 mm in LC2420) within the operating range of this sensor head as shown in FIG.
Install as follows. In this installation, the amount of reflected light at a specific position of the photoreceptor sample can be measured using the reflected light amount measurement mode of the laser displacement meter by using an XY stage often used for optical experiments. .

Here, reference numeral 700 denotes a sensor head, in which a light emitting unit 200 (ultra-high precision laser displacement meter L) is provided.
C2400) and the light receiving unit 300 (the regular reflection measurement sensor head LC2420). 6 in FIG. 6 was measured at 22.5 ° C. in the present invention. XY stage 40
The photoreceptor sample 500 is placed on 0, and the position is changed as indicated by the arrow to measure. In addition, 600 is a controller.

Although the laser wavelength of this measuring instrument is 670 nm, it is not limited to this wavelength. However, it is desirable to use a laser having a wavelength close to the wavelength when an image is actually formed by laser exposure. The position resolution of the measuring instrument is about 20 μm. In order to evaluate the moiré unevenness felt by human eyes, it is appropriate to measure at such a resolution and evaluate the variation. When this measuring method is carried out, the position may be shifted by, for example, 20 μm, and a change in the amount of reflected light may be measured to obtain an interval between the maximum and the minimum as shown in FIG. In practice, the average value of all values of the interval between the distinct local maxima and minima obtained by the measurement is obtained. Thus, it is possible to determine whether the interval between the local minimum and maximum of the variation is 100 μm or more.

The variation due to the position of the amount of reflected light is 1
Measure the length of 00mm at 5000 locations every 20μm,
Assuming that the amount of reflected light is x ₁ ... _X5000 , it can be obtained from the average amount of light as follows.

[0028]

(Equation 1)

If there is a possibility that the measured value may fluctuate due to sampling in the photoreceptor, the measurement is performed at three positions at both ends and the center of the image forming portion of the photoreceptor. You need to make sure that However, when there is little variation depending on the location, the measurement may be performed at any location.

The variation due to the position of the amount of reflected light and the minimum and maximum intervals of the variation vary depending on various conditions.
The state of the surface of the photoreceptor, the state of the surface of the substrate, the state of the interface between the layers, the optical density of each layer, and the like have a great effect. Therefore, by changing these, it is possible to control the variation due to the position of the reflected light amount, and the minimum and maximum intervals of the variation.

With the above ranges, the reason why the effects of the present invention can be obtained is not always clear.
In addition, it can be said that these conditions are combined effects. However, for example, if the minimum and maximum intervals of the variation always have a regularity of 100 μm or less, this is one of the major factors causing moiré.

Hereinafter, the present invention will be described in detail.

The photosensitive layer used in the present invention is preferably formed of a function-separated type containing both a charge transporting substance (CTM) and a charge generating substance (CGM), in particular, each of which is separately coated in layers.

A binder resin for the charge transport layer (CTL),
The charge transport material is not particularly limited as long as it satisfies the above requirements, and a known material can be used.

Specific examples are shown below, but the binder resin and the charge transporting substance are not limited to those shown here.

For example, as the binder resin, bisphenol A type polycarbonate, bisphenol Z type polycarbonate, other polycarbonates, organometallic compounds, polyvinyl butyral, polystyrene, styrene-
Butadiene copolymer, polyvinyl acetate, polyamide, polypropylene, polyurethane, acrylic resin, methacrylic resin, phenolic resin, epoxy resin, silicone resin, poly-N-vinyl carbazole, polyketone, polyvinyl formal, polyarylate, polybutylene terephthalate, polyolefin Vinylidene fluoride, polyvinyl fluoride, polysulfone, polyimide, polyetherimide,
Polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polyacrylamide, polyethylene terephthalate, polyacetylene, high-density polyethylene, low-density polyethylene, etc. can be used alone or in the form of a mixture of two or more or a copolymer of two or more. .

As the charge transporting substance, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives,
Fluorenone derivatives, bisimidazolidine derivatives, styryl derivatives, hydrazone compounds, butadiene derivatives, triphenylmethane, pyrazoline compounds, amine derivatives,
Oxazolone derivative, benzothiazole derivative, benzimidazole derivative, quinazoline derivative, diphenoquinone derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-
Vinylcarbazole, poly-1-vinylpyrene, poly-
9-vinylanthracene and the like.

These charge transporting substances may be used alone or as a mixture of two or more. Also,
The weight ratio of the charge transporting substance to the binder resin in the charge transporting layer can also be arbitrarily set so as to satisfy the requirements of the present invention. Further, the thickness of the charge transport layer can be arbitrarily determined so as to satisfy the requirements of the present invention.

When an intermediate layer is provided in the present invention, a resin-based intermediate layer using a polyamide-based compound such as nylon, or a so-called ceramic-based intermediate layer using an organometallic compound and / or a silane coupling agent (curable layer). Intermediate layer) is preferred.

The charge generation layer is formed by dispersing a charge generation material in a binder resin as required. Examples of the charge generating material include metal or metal-free phthalocyanine compounds, azo compounds such as bisazo compounds and trisazo compounds, squarium compounds, azurenium compounds, perylene compounds, indico compounds, quinacridone compounds, polycyclic quinone compounds, cyanine dyes, xanthene dyes. And a charge transfer complex composed of poly-N-vinylcarbazole and trinitrofluorenone, and the like, but are not limited thereto. These may be used as a mixture of two or more as necessary.

However, in order to achieve the object of the present invention at the highest level, a perylene compound, an imidazole perylene compound or a metal phthalocyanine compound, titanyl phthalocyanine (TiOPc) is preferable. Here, when titanyl phthalocyanine is used as the charge generating substance, it is preferable that the X-ray diffraction spectrum with respect to the Cu-Ka line is titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ± 0.2 °. Further, other remarkable peaks of the titanyl phthalocyanine preferably have 24.1 ± 0.2 ° and 9.5 ± 0.2 °.

As the binder resin usable for the charge generation layer, for example, polystyrene resin, polyethylene resin,
Polypropylene resin, polyacrylic resin, polymethacrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinyl butyral resin, polyepoxy resin, polyurethane resin, polyphenol resin, polyester resin, polyalkyd resin, polycarbonate resin, polysilicone resin, Polymelamine resins, and copolymer resins containing two or more of the repeating units of these resins, such as vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and polymers Examples include, but are not limited to, organic semiconductors, such as poly-N-vinyl carbazole.

Among the above, when the imidazole perylene compound is used as the charge generating substance, a preferable binder is polyvinyl butyral resin. A mixture thereof is given.

In order to reduce fatigue deterioration upon repeated use or to further improve durability, a known antioxidant (hindered phenols, hindered amines, etc.) may be used in each layer of the photoreceptor. et
c. ), A heat-resistant agent, an ultraviolet absorber, an electron-accepting substance, a surface modifier, a plasticizer and the like, and an environment-dependent reducing agent.

In order to further improve the durability, a protective layer or the like may be provided in addition to the photosensitive layer, if necessary. The protective layer may further contain inorganic fine particles, organic fine particles, and the like.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a typical color image forming apparatus of the present invention and an image forming process will be described with reference to FIGS.

In this apparatus, although the exposure incidence angle differs depending on the color, dot exposure of 3 to 15 degrees is performed.

First, as shown in FIGS. 1 and 4, a photoreceptor cartridge 2 removably provided in the image forming apparatus will be described. The endless belt-shaped photoreceptor 1 wound around the upper roller 3, the lower roller 5, and the horizontal roller 7 is vertically stretched by the upper roller 3 and the lower roller 5,
It is driven in the direction of arrow I.

Further, on the surface on which the photoconductor 1 moves upward, the photoconductor 1 is moved in the direction of the closed space formed by the photoconductor 1.
A pressing roller 9 is provided as guide means for pressing the photosensitive member 1 in the closed space direction.

A cleaning unit 1 for removing the developer on the photoconductor 1 is provided above the surface on which the photoconductor 1 moves upward.
1 is provided. This cleaning means 11 is shown in FIG.
This will be described with reference to FIG. On a bracket 15 rotatably provided on the shaft 13, a blade 17 that can contact a surface that moves from below to above the photoconductor 1 is attached.
Further, a spring 1 whose one end is locked to the main body side of the photoreceptor cartridge 2 and the other end is locked to the bracket 15.
9, the bracket 15 is urged in the direction in which the blade 17 presses against the photoconductor 1.

Returning to FIG. 1, below the cleaning means 11, a collection box 21 is provided along the photoreceptor 1 as a collection means for collecting the developer removed by the cleaning means 11.

Next, a latent image forming means for forming a latent image on the photosensitive member 1 will be described. Since the image forming apparatus of the present embodiment is a four-color image forming apparatus, it has four latent image forming means for each color. That is, a Y optical writing unit 25 that forms a Y (yellow) latent image on the photoconductor 1 using laser light, and an M (magenta) latent image on the photoconductor 1 using laser light. And an M optical writing portion 27 for forming
C optical writing section 29 for forming a latent image for (cyan)
And a K optical writing unit 31 that forms a K (black) latent image on the photoreceptor 1 using laser light.

The four optical writing units 25, 27,
Since the configurations of 29 and 31 are the same, the Y optical writing unit 25 will be described with reference to FIGS. 1 and 3 and the description of the other optical writing units will be omitted. In these figures, 33
Is a laser light source that emits a laser light on which a Y image signal is superimposed. The laser light from the laser light source 33 is reflected by the movement of the rotating surface of the polygon mirror 37,
Scanned, fθ lens 39, cylindrical lens 4
After 1, the photosensitive surface of the photoconductor 1 is scanned and exposed. By this scanning exposure, an electrostatic latent image is formed on the photosensitive surface of the photoconductor 1.

Next, as shown in FIGS. 1 and 5, an image forming cartridge 3 detachably provided in the image forming apparatus.
5 will be described. In the image forming cartridge 35, four developing means for developing the electrostatic latent images of each color formed on the photoconductor 1 are provided. That is, the Y optical writing unit 2
5, a Y developing unit 42 for developing the latent image formed, and an M developing unit 4 for developing the latent image formed by the M optical writing unit 27.
3, a C developing section 45 for developing the latent image formed by the C optical writing section 29, and a K developing section 47 for developing the latent image formed by the K optical writing section 31.

The four developing units 42, 43, 45, 4
7, the configuration of the Y developing unit 42 will be described, and the description of the other developing units will be omitted. Screws 51 and 52 agitate and transport the Y developer (in the present embodiment, the developer is a two-component developer composed of a toner and a carrier) transported from a developer reservoir (not shown); 53
Reference numeral denotes a supply roller for supplying a developer to the developing sleeve 55. The developing sleeve 55 carries a developer, reversely develops the electrostatic latent image on the photoconductor 1, and forms a toner image on the photoconductor 1.

Further, in the image forming cartridge 35,
A band electrode of a charging unit for applying a charge to the photoconductor 1 is provided corresponding to the developing units 42, 43, 45, and 47 of the respective colors. That is, a band electrode 61 for Y, a band electrode 63 for M,
A band electrode 65 for C and a band electrode 67 for K.

On the other hand, the charging means of each color in the present embodiment is provided with grids 71, 7 for controlling the charging potential on the photosensitive member 1.
3,75,77 but these grids 7
1, 73, 75 and 77 are provided on the side of the photoreceptor cartridge 2 as shown in FIG.

Returning to FIG. 1, reference numeral 81 denotes a paper feed unit,
Is provided in the cassette 83. The transfer paper P in the cassette 83 is carried out by the carry roller 85, nipped and carried by the carry roller pair 87 and the registration roller 88, and fed to the transfer unit 91.

The transfer section 91 includes a transfer pole 93 for transferring the developer image on the photosensitive member 1 to transfer paper P by corona discharge,
A separation pole 95 for separating the transfer paper P from the photoconductor 1 by an AC discharge is provided.

Reference numeral 100 denotes a fixing unit that applies heat and pressure to the transfer paper P by sandwiching the pair of heat rollers 101 to fuse the toner to the transfer paper P. Reference numeral 110 denotes a discharge tray for transferring the transfer paper P that has been thermally fixed. It is a pair of transport rollers for nipping and transporting up to 111.

Reference numeral 120 denotes a paper feed path through which transfer paper P of another size conveyed from a paper feed unit provided outside the apparatus passes.

Next, the operation of the above configuration will be described. When the photoconductor 1 is driven in the direction of arrow I, first, the photoconductor 1 is charged by a charging means for Y including a band electrode 61 and a grid 71.
The upper portion has a predetermined charging potential.

Next, an electrostatic latent image is formed on the photosensitive member 1 by the Y optical writing section 25. Then, the toner in the developer carried on the developing sleeve 55 of the Y developing unit 42 moves onto the photoconductor 1 due to the Coulomb force, and a toner image is formed on the photoconductor 1.

The same operation is performed for the remaining colors, that is, M,
The process is performed for C and K to form Y, M, C, and K toner images on the photoconductor 1.

On the other hand, the transfer paper P is fed from the paper feeding unit 81 by the transport roller 85 and the transport roller pair 87 to the transfer unit 9.
It is conveyed toward 1.

The fed transfer paper P is synchronized with the toner image on the photoreceptor 1 by a registration roller 88 and then fed to a transfer unit 91 in synchronization with the toner image.
And the developer image on the photoconductor 1 is transferred to the transfer paper P.

Further, the transfer paper P is separated from the photoreceptor 1 by the charge eliminating action of the separation pole 95.

Next, the transfer paper P is heated by the fixing unit 100,
The toner is pressed, the toner is fused to the transfer paper P, and is discharged onto the discharge tray 111 by the pair of transport rollers 110.

The surplus toner on the photosensitive member 1 after the transfer is removed by the blade 17 of the cleaning means 11 and stored in the collection box 21.

According to the image forming apparatus having the above structure, the cleaning means 11 for removing excess toner on the photosensitive member 1 is provided above the surface on which the photosensitive member 1 moves from the bottom to the top. By providing the collection box 21 for collecting the surplus toner, the removed toner can be dropped by gravity without using the conveying means, and the mechanism can be simplified and the apparatus can be downsized.
The cleaning means 11 and the collection box 21
Is provided along the photoconductor 1, it is possible to prevent the heat from the fixing unit 100 from adversely affecting the photoconductor 1.

Further, the photosensitive member 1 is bent using the pressing roller 9 in the direction of the closed space formed by the photosensitive member 1, and the collection box 21 is provided in the space formed by the bending, so that the apparatus is further improved. The size can be reduced.

Further, by providing the photoreceptor cartridge 2 with the grids 71, 73, 75, 77 having the same life as the photoreceptor 1, the photoreceptor 1 and the grid 7 can be operated in one operation.
1, 73, 75 and 77 can be exchanged, and parts exchange becomes easy.

Further, grids 71, 73, 75, 77
Are provided in the photoreceptor cartridge 2 and grids 71 and 7 are provided.
By integrating 3,75,77 and photoconductor 1,
The distance between the grids 71, 73, 75, 77, which have strict distance accuracy, and the photoconductor 1 can always be maintained at a constant accuracy.

Further, since the band electrodes 61, 63, 65, and 67 having the same life as the developing units 42, 43, 45, and 47 are provided in the image forming cartridge 35, the developing unit 42, 43 43, 45, 47 and band electrodes 61, 63,
65, 67 can be replaced, and parts replacement is simplified.

Further, the developing units 42, 43, 4 of the respective colors
5, 47 and the respective band electrodes 6 of the charging means for each color.
1, 63, 65, 67 are integrated into the image forming cartridge 35, so that even in a multicolor image forming apparatus, the developing sections 42, 43, 45, 47 and
1, 63, 65 and 67 can be replaced, and parts replacement is simplified.

The present invention is not limited to the above embodiment. In the above embodiment, the description has been given of a multicolor image forming apparatus, but the present invention can be applied to a monochromatic image forming apparatus.

[0077]

EXAMPLES The embodiments of the present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 As a photoreceptor substrate, a polyester base having a thickness of 75 μm and having a surface roughness Rz of 3.72 μm and a back surface Rz of 4.99 μm (a Teijin U4Z base) was used. . The photoreceptor was obtained by depositing aluminum on the above substrate, laminating an intermediate layer and a charge generation layer in this order, and then coating the charge transport layer coating solution to a thickness of 20 μm after drying.

Here, the intermediate layer is made of polyamide (manufactured by Toray Industries, Inc.).
(CM-8000) was mixed and dissolved in 80 parts by weight of methanol and 20 parts by weight of 1-butanol, and was applied by dip coating to a thickness of 1.0 μm.

The coating solution for the charge generation layer is represented by the following formula 1
20 parts by weight of a Y-type titanyl phthalocyanine compound and a silicone resin (KR-5240, manufactured by Shin-Etsu Chemical Co., Ltd.)
0 parts by weight and 800 parts by weight of 2-butanone were mixed and dispersed by a sand mill for 10 hours. This was dip-coated on the intermediate layer to prepare a charge generation layer having a thickness of 0.25 μm.

The coating solution for the charge transport layer was prepared by adding a compound B-1 represented by the following Chemical Formula 1 as a charge transport material to a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.) in addition to a binder dissolved in an appropriate amount in 1,2-dichloroethane. Iupilon Z-300)
It was obtained by mixing and dissolving 75 parts by weight with respect to 100 parts by weight.

[0082]

Embedded image

The obtained photosensitive member was designated as photosensitive member No. Let it be 1.

Example 2 Example 1 was repeated except that the photoreceptor substrate in Example 1 was replaced with a polyester base having a surface Rz of 3.12 μm and a rear surface Rz of 3.87 μm, on which aluminum was deposited. In the same manner as in 2 was obtained.

Example 3 The same procedure as in Example 1 was repeated except that the charge generating substance was changed to C-2. 3 was obtained.

Comparative Example 1 In Example 1, instead of the polyester base having a thickness of 75 μm and having a surface roughness Rz of 3.72 μm and a rear surface Rz of 4.99 μm (U4Z base manufactured by Teijin) in Example 1, 75μm thickness without surface roughening
Comparative Photoconductor N in the same manner as in Example 1 except that a polyester base of
o. 1 was obtained. Its surface roughness Rz was 2.01 μm.

Comparative Example 2 In Example 3, a polyester base having a thickness of 75 μm and having a surface roughness Rz of 3.72 μm and a rear surface Rz of 4.99 μm (U4Z base manufactured by Teijin Limited)
Instead of having a thickness of 100
Comparative Photoconductor No. 1 was prepared in the same manner as in Example 3, except that a smooth surface was formed by evaporating aluminum on a polyester base of μm. 2 was obtained. Its surface roughness Rz was 1.80 μm.

Comparative Example 3 The procedure of Example 1 was repeated, except that the photoreceptor substrate used in Example 1 was replaced with a polyester base having a surface Rz of 7.30 μm and a back surface having an Rz of 6.50 μm, on which aluminum was deposited. In the same manner as in Comparative Photoconductor No. 3 was obtained.

Comparative Example 4 Comparative Photoconductor No. 1 was prepared in the same manner as in Example 1 except that the thickness of the charge generation layer was changed to 0.41 μm. 4 was obtained.

Comparative Example 5 Comparative Photoconductor No. 5 was prepared in the same manner as in Example 3 except that the thickness of the charge generation layer was changed to 0.41 μm. 5 was obtained.

Comparative Example 6 Comparative Photoconductor No. 3 was prepared in the same manner as in Example 3 except that the thickness of the charge generation layer was changed to 0.55 μm. 6 was obtained.

The measurement of the value of the variation depending on the position of the amount of reflected light in the regular reflection direction of each photoconductor and the minimum and maximum intervals of the variation were performed by the above-described method. The measuring device and the measuring method described with reference to FIGS. 6 and 7 were used.

The measurement was carried out at intervals of 20 μm over a measuring range of 100 mm, and the variation was obtained by calculating the standard deviation from the data of 5000 points, and calculating% with respect to the average value. Also, the maximum,
For the minimum interval, an average interval was obtained from the measured data.

The produced photoreceptor was adhered by ultrasonic thermal fusion in a belt shape such that the photosensitive layer faced up.

Next, the photosensitive member No. Nos. 1 to 3 and Comparative Photoconductor Nos. 5000 sheets were continuously printed by the printer shown in FIG. 1 and image evaluation was performed under the standard bias and the standard -100V.

Characteristic evaluation Moiré Moiré is Y, M, C, K every 1000 sheets under each condition.
Of each color image and a gray image of Y + M + C + K were imaged at a density of 0.3, respectively, and visually judged.

Evaluation Criteria 5: None at all under any conditions 4: Appeared slightly under any of the conditions, but no practical problem 1: A level that is a serious problem in practical use

2. Resolving power Information obtained by changing the number of fine lines drawn in a width of 1 mm was printed out, and the number of obtained print samples was examined to determine how many readable.

Table 1 shows the results.

[0100]

[Table 1]

As is evident from Table 1, the photosensitive member No. in the present invention. In Nos. 1 to 3, good images having substantially no moiré and high resolving power were obtained.

[0102]

According to the present invention, a method for reliably preventing moiré without excessively roughening the surface of a substrate has been found, and is applied to an electrophotographic photosensitive member. Can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged configuration diagram of a cleaning unit in FIG.

FIG. 3 is a plan view of an optical writing unit in FIG. 1;

FIG. 4 is a configuration diagram when the photosensitive member cartridge is detached from the image forming apparatus in FIG.

FIG. 5 is a configuration diagram when the image forming cartridge is detached from the image forming apparatus in FIG.

FIG. 6 is a view for explaining a method of measuring a variation depending on a position of a reflected light amount and a minimum maximum interval of the variation.

FIG. 7 is a view for explaining a variation depending on a position of a reflected light amount and a measurement result of a minimum maximum interval of the variation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Photoreceptor cartridge 3 Upper roller 5 Lower roller 7 Lateral roller 9 Press roller 11 Cleaning means 35 Image forming cartridge 61, 63, 65, 67 Band electrode 71, 73, 75, 77 Grid 200 Light emitting part (ultra high precision Laser displacement meter LC240
0) 300 light-receiving unit (sensor head LC24 for specular reflection measurement)
20) 400 XY stage 500 Photoconductor sample 600 Controller 700 Sensor head

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Yasuda 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H068 AA29 AA34 AA35 AA59 FB01 FB05 FB07 FC05 2H076 AB02 AB18

Claims (3)

[Claims] 1. An image forming apparatus for forming a latent image by dot exposure at an exposure incident angle of 3 to 20 degrees using an electrophotographic photosensitive member having a photosensitive layer provided on a conductive layer. Variation due to the position of reflected light amount is 30 ~
70%, and the interval between the local minimum and maximum of the variation is 100 μm.
m or more. 2. The image forming apparatus according to claim 1, wherein a laser beam is used as a light source for the dot exposure. 3. An electrophotographic photoreceptor for use in an image forming apparatus according to claim 1, further comprising a photosensitive layer having a multilayer structure comprising at least a charge generation layer and a charge transport layer on the conductive layer. body.