JPH0810333B2 - Photoconductor - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly to a photoreceptor suitable for an electrophotographic printer of the type in which a laser beam is imagewise line-scanned and an image forming method thereof.

Up to now, an electrophotographic printer of a line scanning type using a laser beam uses a gas laser having a relatively short wavelength, such as a helium-cadmium laser, an argon laser or a helium-neon laser, as a laser beam, and further, an electron used for the laser. As a photographic photoreceptor, a CdS-binder-based photosensitive layer forming a thick photosensitive layer, a charge transfer complex (IBM Journal of the Res)
each and Development-ment, 197
January 1st, P. 75-P. No. 89) was used, the laser beam did not cause multiple reflection in the photosensitive layer, and thus an interference fringe pattern image did not actually appear during image formation.

However, in recent years, a semiconductor laser has been used in place of the above-mentioned gas laser in order to design the device in a compact size and a low cost. Since this semiconductor laser generally has an oscillation wavelength in a long wavelength region of 750 nm or more, an electrophotographic photosensitive member having high sensitivity characteristics in the long wavelength region is required. Therefore, an electrophotographic photosensitive member for this purpose Has been developed.

Long-wavelength light (eg 6
Examples of the photoconductor having a photosensitivity to (00 nm or more) include, for example, a laminated electrophotographic photoconductor or a selenium-tellurium film having a laminated structure of a charge generation layer and a charge transport layer containing a phthalocyanine pigment such as copper phthalocyanine and aluminum chloride phthalocyanine. An electrophotographic photoconductor using a film is known.

When such a photosensitive member having sensitivity to long-wavelength light is attached to a laser beam scanning type electrophotographic printer and laser beam exposure is performed, an interference fringe pattern appears in the formed toner image. However, it had a drawback that a good reproduced image could not be formed. One of the reasons for this is that, for example, a long-wavelength laser is not completely absorbed in the photosensitive layer, and the transmitted light is specularly reflected on the surface of the substrate, which causes multiple reflected light of the laser beam in the photosensitive layer. Is caused by interference with the reflected light on the surface of the photosensitive layer.

As a method of solving this drawback, a method of roughening the surface of a conductive substrate used in an electrophotographic photosensitive member up to now by an anodic oxidation method or a sandblast method,
Although it has been proposed to eliminate the multiple reflection occurring in the photosensitive layer by a method of using a light absorbing layer or an antireflection layer between the photosensitive layer and the substrate, as a practical problem, interference fringes appearing at the time of image formation. The pattern could not be completely eliminated. In particular, the method of roughening the surface of the conductive substrate makes it difficult to form a rough surface having a uniform roughness. May be formed. Therefore, this large roughness portion acts as a carrier injecting portion into the photosensitive layer and causes white spots (or black spots when the reversal development method is used) during image formation. There wasn't. In addition, it is difficult to manufacture a conductive substrate having a uniform rough surface in the same lot, and there are many points to be improved. Further, the method using the light absorption layer or the antireflection layer also has a drawback that the interference fringe pattern cannot be sufficiently eliminated and the manufacturing cost is increased.

It is an object of the present invention to provide a novel photoreceptor (for example, an electrophotographic photoreceptor) which eliminates the above-mentioned drawbacks and an image forming method thereof.

Another object of the present invention is to provide an electrophotographic photoreceptor which is easy to manufacture, that is, a conductive substrate having uniform surface characteristics in the same lot can be easily manufactured.

An object of the present invention is to provide a photoreceptor having a coating layer having a photosensitive layer on a substrate, in which the thickness of the coating layer is regularly changed between minute widths of the coating layer. As shown in FIGS. 1 and 4, such a regular change in film thickness has concave portions with a minute width, that is, grooves, which are arranged in parallel in the circumferential direction of the surface of the cylindrical substrate. This is achieved by the photoconductor formed by the cross section along the direction of the minute width of the groove having a regular shape. Preferably, the groove on the surface of the cylindrical substrate is λ / 2 along the minute width of the groove.
(Λ; wavelength during image exposure) or more (preferably 0.1 μm to
This is achieved by a photoreceptor in which a tapered reflective surface having a height of 100 μm, particularly preferably 0.3 μm to 30 μm) is formed.

FIG. 1 shows an example of a conductive substrate used in the present invention.

The conductive substrate 1 shown in FIG. 1 has linear projections 2 and tapered reflecting surfaces 3 (corresponding to cutting lines) regularly formed in every minute width d. The linear protrusion 2 and the tapered reflecting surface 3 can be formed in a spiral shape when the conductive substrate 1 is a cylindrical substrate, but in addition, for example, the linear protrusion 2 and the tapered reflecting surface 3 can be waved vertically to the longitudinal direction of the cylindrical substrate. It can be formed in a mold shape, and further, the linear protrusions 2 and the Taber reflecting surface 3 can be simultaneously formed in a vertical shape and a parallel shape with respect to the longitudinal direction.

FIG. 2 shows the conductive substrate 1 shown in FIG. 1, respectively.
2 is an enlarged cross-sectional view showing the state in which, for example, five linear projections 2 and a tapered reflecting surface 3 are formed per 1 mm width. Of course, the present invention is not limited to the above-mentioned example, and the minute width d
Can be less than 1000 μm (having one linear protrusion 2 per 1 mm width) as described above, preferably 10 μm (having 100 linear protrusions 2 per 1 mm width) to 500 μm (1 mm It has a range of 2 linear protrusions 2 per width).

The tapered reflecting surface 3 shown in FIG. 2 is a surface corresponding to a cutting line formed by regularly cutting with a cutting edge or the like, and its cross-sectional shape may be a semicircular shape as shown in the drawing. Alternatively, it may have another shape such as a U shape, a V shape, a sawtooth shape, a trapezoidal shape or a semi-elliptical shape.

The tapered reflecting surface 3 has a taper of height h, and the height h of this taper is λ / 2 (λ; at the time of image exposure) in order to effectively eliminate the interference fringe pattern appearing at the time of image formation. (Wavelength of incident light) or more. Specifically, as described above, the height h of the taper is preferably 100 μm or less, and particularly 0.3 μm to 30 μm.
It is desirable to set within the range. When the height h of the taper is 100 μm or more, the barrier layer formed on the surface of the linear projection 2 cannot cover most of the linear projection 2, and titanium oxide whose surface is conductively treated is dispersed in the resin. Even if the conductive layer is formed, the surface of the conductive layer still forms a protrusion corresponding to the linear protrusion 2 of the conductive substrate 1, and the protrusion should be sufficiently covered with the barrier layer. In this case as well, carrier injection from the protrusions into the photosensitive layer occurs, so that the carrier injection portions appear as white spots during image formation, and (in the case of reversal development, black spots appear. It is not desirable for image formation (as it appears).

The taper reflecting surface 3 has, for example, a tool having a semicircular, semi-elliptical, U-shaped, V-shaped or trapezoidal cutting edge fixed to a milling machine or a lathe, and the conductive substrate is moved regularly. It can be formed by a cutting process by performing.

In a preferred embodiment of the invention, a radius of 0.1
Pitch 1 with a bit having a semicircular cutting edge of mm to 50 mm
By cutting with a thickness of 000 μm or less, the tapered reflecting surface 3 having a shape as shown in FIG. 2 can be formed. The productivity used in this case can be improved by using multiple bytes in which a plurality of bytes are connected in parallel.

Further, the present invention can employ the anodizing method or the surface treatment method of immersing it in a solution of sodium silicate, potassium fluorozirconate or the like after the above-mentioned cutting treatment. The method disclosed in JP-A-5125, that is, the method of immersing in an aqueous solution of an alkali metal silicate after anodizing treatment can also be used. The above-described anodizing method is carried out, for example, by passing an electric current in an aqueous solution or a non-aqueous solution of an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid, boric acid or an organic acid such as oxalic acid, sulfamic acid or the like and using a conductive substrate as an anode. Can be done.

As the conductive substrate 1 used in the present invention, a metal such as aluminum, brass, copper or stainless steel, or a film obtained by vapor deposition of aluminum, tin oxide or indium oxide on a plastic such as polyester can be used.

FIG. 3 schematically shows a mode in which the electrophotographic photosensitive member is irradiated with a laser beam as coherent light. FIG. 3A shows an example using a conventional electrophotographic photosensitive member, and FIG. 3B shows an example using the electrophotographic photosensitive member of the present invention.

In FIG. 3A, the photosensitive layer of the electrophotographic photosensitive member is shown.
Laser beam I on 4₁On the surface of the photosensitive layer 4
Reflected light R₁And the laser beam I₁Of the photosensitive layer 4
Laser beam I transmitted through the inside₂On the conductive substrate 1
It reaches the formed light diffusion surface 5, where the laser beam I
₂Part of the light is diffused light K₁, K₂…
Occurs, but with the remaining amount of light, strong specular reflection light R₂Yields
Furthermore, this regular reflection light R₂Of the photosensitive layer 4 and the air layer
Regular reflection at the interface, reflected light R₂It becomes' and the photosensitive layer 4 again
Will pass inside. Not shown next
Reflected light R₂A part of ′ receives the light diffusion effect by the light diffusion surface 5.
Specular reflected light R₃Cause In this way, the conductive substrate 1
Even if the light diffusion surface 5 is formed on the
Light I₁Is irradiated, multiple reflections are sequentially generated inside the photosensitive layer 4.
The reflected light R ₁, R₂, R₃Between ...
Causes a phase difference of each wavelength, which causes interference.
Will be. On the other hand, the mode shown in FIG.
The examples of the present invention are shown, but the electrophotographic photoreceptor of the present invention
Has a tapered reflecting surface 3 formed on the conductive substrate 1.
The photosensitive layer 4 is formed on the surface thereof. Photosensitive layer 4
Incident light I directed toward₁Is part of the surface of photosensitive layer 4
Is reflected and reflected light R₁And the other part is transmitted light I₂When
Then, it passes through the inside of the photosensitive layer 4 and at the tapered reflecting surface 3.
Regular reflection and reflected light R₂Cause This reflected light R₂Part of
Is the reflected light R specularly reflected at the interface between the photosensitive layer 4 and the air layer.₂′
Then, the light is regularly reflected by the tapered reflecting surface 3.

In this way, it is considered that the incident light I ₁ is sequentially subjected to multiple reflection inside the photosensitive layer 4 and causes interference between the reflected lights R ₁ , R ₂ , R ₃ ...

However, according to the research conducted by the present inventors, after the photosensitive layer 4 formed on the conductive substrate 1 having such a tapered reflecting surface 3 is charged, image exposure by a laser beam and toner development are sequentially performed. When applied to form an image, it was surprisingly found that no interference fringe pattern was generated in this image. The reason for this is, to the best of our knowledge, the interference fringe pattern generated by the light rays reflected by the tapered reflecting surface 4 is formed in a fine pattern that is invisible to the eye, and the toner particles are generally 1
Since the particle size is about 5 to 30 μm, which is relatively large compared to the interference fringe pattern, it is considered that the fine interference fringe pattern does not appear during image formation. However, here, the theoretical analysis regarding the elimination of the interference fringe pattern by the tapered reflecting surface 3 will be left to a sufficient examination and research later. In any case, by providing the tapered reflecting surface 3 between the photosensitive layer 4 and the conductive substrate 1, the interference fringe pattern, which has been exposed at the time of image formation by the conventional method, is not completely exposed. It ’s amazing,
The present invention has been completed based on this phenomenon. FIG.
Represents a preferred embodiment of the present invention. The electrophotographic photosensitive member shown in FIG. 4 has a linear projection 2 and a tapered reflection surface 3.
A photosensitive layer 10 having a laminated structure composed of a conductive layer 6, a barrier layer 7, a charge generation layer 8 and a charge transport layer 9 is sequentially coated on a conductive substrate 1 having

As the above-mentioned conductive layer 6, for example, a vapor-deposited film of a conductive metal such as aluminum, tin or gold, or a film in which a conductive powder is dispersed and contained in a resin can be used. Examples of the conductive powder used in this case include metal powders such as aluminum, tin and silver, carbon powder and conductive pigments mainly composed of metal oxides such as titanium oxide, barium sulfate, zinc oxide and tin oxide. Can be mentioned.
Further, the conductive layer 6 may contain a light absorber.

The resin in which the conductive pigment is dispersed has (1) strong adhesion to the substrate, (2) good dispersibility of the powder, and (3) sufficient solvent resistance. ,
It can be used if it meets the conditions such as
Thermosetting resins such as curable rubber, polyurethane resin, epoxy resin, alkyd resin, polyester resin, silicone resin, and acrylic-melamine resin are suitable. The volume resistivity of the resin in which the conductive pigment is dispersed is 10 ¹³ Ωcm or less,
It is preferably 10 ¹² Ωcm or less. for that reason,
In the coating film, the conductive pigment is preferably contained in the coating film in a proportion of 10 to 60% by weight.

The conductive layer 4 may contain a surface energy lowering agent such as silicone oil or various kinds of surfactants, whereby a uniform coating surface with few coating defects can be obtained. The conductive powder can be dispersed in the resin by a conventional method such as a roll mill, a pole mill, a vibrating ball mill, an attritor, a sand mill or a colloid mill. When the substrate has a sheet shape, wire bar coating is used. Blade coating, knife coating, roll coating, screen coating, etc. are suitable, and when the substrate is cylindrical, the dip coating method is suitable.

The conductive layer 6 is generally formed in a film thickness of about 1 μm to 50 μm, preferably about 5 μm to 30 μm, so that the height h of the projection 2 of the conductive substrate 1 is 100.
In the case of μm or less, the surface defect can be sufficiently hidden.

A barrier layer 7 having a barrier function and an adhesive function is provided between the conductive layer 6 and the photosensitive layer 10. The barrier layer 7 can be formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin and the like.

The barrier layer 7 has a thickness of 0.1 micron to
5 microns, preferably 0.5 to 3 microns are suitable.

The charge generation layer 8 in the present invention comprises azo pigments such as Sudan Red, Diane Blue and Dienas Green B, quinone pigments such as Argol Yellow, pyrene quinone, indanthrene brilliant violet RRP, quinocyanine pigments, berylylene pigments and indigo pigments. , Indigo pigments such as thioindigo, bisbenzimidazole pigments such as Indian first orange toner, phthalocyanine pigments such as copper phthalocyanine and aluminum chloro-phthalocyanine, quinacridone pigments and Japanese Patent Application No. 57-1652.
A charge-generating substance selected from the azulene compounds described in No. 63 is dispersed in a binder resin such as polyester, polystyrene, polyvinyl butyral, polyvinylpyrrolidone, methyl cellulose, polyacrylic acid esters, and cellulose ester. . Its thickness is 0.01 ~
It is about 1 μ, preferably about 0.05 to 0.5 μ.

The charge transport layer 9 has a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, coronene or indole in the main chain or side chain, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, It is formed by dissolving a compound having a nitrogen-containing cyclic compound such as pyrazoline, thiadiazole or triazole, or a hole transporting substance such as a hydrazone compound in a resin having film-forming properties. This is because the charge transporting substance generally has a low molecular weight and is poor in film forming property by itself. Such resins include polycarbonate, polymethacrylates, polyarylate, polystyrene, polyester, polysulfone, styrene-acrylonitrile copolymer, styrene-methyl methacrylate copolymer, and the like.

The thickness of the charge transport layer 9 is 5 to 20 μm.
Further, the above-mentioned charge generation layer 8 can be used as the photosensitive layer 10 having a structure in which it is laminated on the charge transport layer 9.

Further, the above-mentioned photosensitive layer 10 is not limited to the above-mentioned type, but may be, for example, the above-mentioned IBM Journal.
of the Research and Devel
Opment, January 1971, P. 75-P. 89, Charge transfer complexes consisting of polyvinylcarbazole and trinitrofluorenone, US Pat. No. 4,315,598.
No. 3, U.S. Pat. No. 4,327,169, etc., and a photosensitive layer using a pyrylium-based compound or a well-known photosensitive material in which a resin contains an inorganic photoconductive substance such as zinc oxide or cadmium sulfide dispersed therein. Layers and selenium,
It is also possible to use a vapor deposited film such as selenium-tellurium.

The electrophotographic photosensitive member of the present invention can be used in an electrophotographic printer using a semiconductor laser having a relatively long wavelength (for example, 750 nm or more), but other laser beams such as helium-neon laser and helium. -Suitable for electrophotographic printers using cadmium laser, argon laser, etc. The present invention can completely eliminate the interference fringe pattern at the time of image formation which has been revealed by the conventional method when such a coherent light such as a laser beam is used as a light source, and a black spot ( It also has an advantage that black spots can be effectively eliminated.

That is, an electrophotographic printer using a laser beam generally applies a positive image-like scan exposure (image scan exposure) in response to an image signal to the laser beam after charging the electrophotographic photosensitive member, and a back image is statically exposed. An electrostatic latent image is formed, and then a developer having a toner having the same polarity as that of the electrostatic latent image is applied to the electrostatic latent image surface so that the toner is attached to the imagewise exposed positive imagewise exposed portion. The reversal development method is adopted, but in the case of this reversal development method, black spot-like unnecessary toner adhesion occurs in the formed image. This is because the rough surface formed by the sandblasting method has a large distribution state between the protrusions having a small height and the protrusions having a large height, and a uniform rough surface is not formed. Carriers are injected into the charge generation layer from the large protrusions, the carriers injected from the protrusions are electrostatically neutralized with the charged charges during charging, and are electrically imagewise exposed. Cause the formation of black spots.

On the other hand, in the electrophotographic photosensitive member of the present invention, as mentioned above, the surface of the conductive substrate is regularly cut by the cutting tool fixed to the milling machine or the lathe, so that a uniform height is obtained. Since the tapered reflecting surfaces having a certain height are formed in parallel along the direction of the minute width, there is no carrier injection portion and no black spots appear even if the above-described reversal development method is adopted. This point will be described in detail in the embodiments described below. Of course, the present invention is not limited to the above-mentioned reversal developing method, and various developing methods such as cascade developing method, magnetic brush developing method, powder cloud developing method, jumping developing method and liquid developing method can also be adopted.

The present invention will be described below with reference to examples. Example 1 After fixing a cutting tool to a lathe by pressing a cutting blade against one end of cylindrical aluminum having a diameter of 60 mm and a length of 258 mm so as to cut at a depth of 1.8 μm, while rotating the cylindrical aluminum. When the cutting edge of the cutting tool was moved to the other end of the cylindrical aluminum at a feed rate of 200 μm per revolution of the cylindrical aluminum to perform cutting, a tapered reflection surface having a cross-sectional shape shown in FIG. 2 was formed at a pitch of 200 μm. It was

The surface of the cylindrical aluminum thus cut and processed is used as a universal surface profilometer (SE
-3C), the measured value is 1.8 with a width of 200 μm.
It was found that the tapered reflecting surface having a height of μm is regularly formed at every 200 μm pitch.

Next, 25 parts by weight of titanium oxide (ECT-62) manufactured by Titanium Industry Co., Ltd., 25 parts by weight of titanium oxide (SR-1T) manufactured by Sakai Industry Co., Ltd., and 25 parts by weight of Dainippon Ink Co., Ltd. Phenol resin (Priofen J325) was mixed with 500 parts by weight of methanol and methyl cellosolve (methanol / methyl cellosolve = 4 parts by weight / 15 parts by weight),
After stirring, the mixture was dispersed with 50 parts by weight of glass beads having a diameter of 1 mm in a sand mill disperser for 10 hours.

Silicone oil (SH289A) manufactured by Toshiba Silicone Co., Ltd. as a solid content is 50 pp in this dispersion.
m and then stirred to prepare a conductive layer-forming coating liquid.

The coating liquid for forming the conductive layer is formed on the surface of the cylindrical aluminum which has been cut as described above so that the film thickness after drying is 20 μm.
m was applied by dip coating, and then heat-dried at 140 ° C. for 30 minutes to form a conductive layer.

Next, 10 parts by weight of a copolymerized nylon resin (trade name: Amilan CM-8000, manufactured by Toray Industries, Inc.) was dissolved in a mixed solution of 60 parts by weight of methanol and 40 parts by weight of butanol, and the solution was placed on the conductive layer. By dip coating, a 1 μm thick polyamide resin layer was provided. Next, 1 part by weight of ε-type copper phthalocyanine (Rionol Blue ES, manufactured by Toyo Ink Co., Ltd.), 1 part by weight of butyral resin (Eslec BM-2; manufactured by Sekisui Chemical Co., Ltd.) and 1 part by weight of cyclohexanone 1 part by weight.
After the dispersion was carried out for 20 hours by a sand mill disperser containing mmφ glass beads, it was diluted with 20 parts by weight of methyl ethyl ketone. This solution was applied on the previously formed polyamide resin layer by dip coating and dried to form a charge generation layer. The film thickness at this time was 0.3 μm.

Then, a hydrazone compound 1 having the following structural formula
0 parts by weight

[0043]

Embedded image And 15 parts by weight of styrene-methyl methacrylate copolymer resin (trade name: MS200; manufactured by Iron Manufacturing Co., Ltd.) were dissolved in 80 parts by weight of toluene. This solution was applied onto the charge generation layer and dried with hot air at 100 ° C. for 1 hour to give 16 μm.
A thick charge transport layer was formed.

The electrophotographic photosensitive member thus prepared was loaded into a Canon laser beam printer LBP-CX (manufactured by Canon Inc.), which is an electrophotographic printer of a reversal development system equipped with a semiconductor laser having an oscillation wavelength of 778 nm. Later, line scanning was performed on the entire surface to form an image with a black toner image on the entire surface, and no interference fringe pattern appeared in this all black image.

Next, the operation of line-scanning the laser beam in accordance with the character signal and forming characters as an image is repeated 2000 times under the condition of a temperature of 15 ° C. and a relative humidity of 10%, and the 2000th copy character image is taken out. It was When the number of black spots (black spots) having a diameter of 0.2 mm or more in this copy character image was measured, no black spots were found at all. Comparative Example 1 As a comparative experiment, the method of roughening the surface of cylindrical aluminum by sandblasting was adopted instead of the cutting method used when the electrophotographic photosensitive member of Example 1 was prepared. An electrophotographic photosensitive member was prepared in the same manner as in Example 1. At this time, the surface condition of the cylindrical aluminum surface-roughened by the sandblast method was measured with a universal surface profilometer (SE-3C) of Kosaka Laboratory before the conductive layer was formed. It was found to be 1.8 μm.

When this electrophotographic photosensitive member for comparison was attached to the laser beam printer used in Example 1 and the same measurement was carried out, clear interference fringes were formed in the entire black image. Also, in the 2000th copy character image, there are about 3 black spots with a diameter of 0.2 mm or more per 10 cm ^2.
There were 0 formed, and the image was extremely difficult to see. Example 2 Fine particle zinc oxide (Sazex 200 manufactured by Sakai Chemical Industry Co., Ltd.)
0), 10 g of acrylic resin (Dianal LR009 manufactured by Mitsubishi Rayon Co., Ltd.), 10 g of toluene and 10 mg of an azurenium compound having the following structural formula were sufficiently mixed in a ball mill to prepare a coating solution for photosensitive layer.

Azurenium compound (Japanese Patent Application No. 57-165
No. 263)

[0048]

Embedded image This photosensitive layer coating solution was provided in place of the photosensitive layer having a laminated structure composed of the charge generation layer and the charge transport layer used in Example 1 so that the film thickness after drying was 21 μm. An electrophotographic photoreceptor was prepared by the same method.

This electrophotographic photosensitive member was attached to the laser beam printer used in Example 1 (however, the charging device was changed so that the charging was positive), and the same measurement was carried out. It was found that there was no interference fringe pattern inside, and black spots with a diameter of 0.2 mm or more were not found at all in the 2000th copy of the character, and it was an extremely good image. Example 3 The machined cylindrical aluminum of Example 1 was anodized by a conventional method to form a thin film of aluminum oxide,
A selenium-tellurium film (tellurium; 10% by weight) was formed thereon with a film thickness of 15 μm by a vacuum vapor deposition method.

When this electrophotographic photosensitive member was attached to the laser beam printer used in Example 2 and the same measurement was carried out, the same result was obtained. Example 4 After fixing a cutting tool to a lathe by pressing a cutting blade against one end of cylindrical aluminum having a diameter of 60 mm and a length of 258 mm so as to cut at a depth of 0.8 μm, 20 μm per one rotation of cylindrical aluminum The cutting process was performed up to the other end at a feed rate of. The universal aluminum surface shape measuring instrument (SE-
3C), it is 0.8μm in 20μm width
It was found that the tapered reflecting surface having a height of 10 μm was regularly formed at every 20 μm pitch.

On this cylindrical aluminum, Example 1
The electroconductive layer, the polyamide resin layer, the charge generation layer and the charge transport layer used in Step 1 were sequentially applied to prepare an electrophotographic photoreceptor. This was attached to the laser beam printer used in Example 1, and an image was formed by the same method. As a result, when a black image was formed on the entire surface, no interference fringe pattern appeared in the image. When the 2000th character image was taken out and observed for the presence of black spots, no black spots were found in the character image. Comparative Example 2 Instead of the cutting method used when the electrophotographic photosensitive member of Example 4 was prepared, a method of roughening by a sandblast method was adopted. The sandblast method used at this time was set so that the average surface roughness would be 0.8 μm (measured by Universal Surface Profile Measuring Instrument SE-3C of Kosaka Laboratory).

On the roughened cylindrical aluminum, a conductive layer, a polyamide resin layer, a charge generation layer and a charge transport layer similar to those in Example 1 were sequentially coated to prepare a comparative electrophotographic photoreceptor. An image was formed in the same manner as in Example 1. As a result, it was found that when a black image was formed on the entire surface, a clear interference fringe pattern appeared in the image.
Further, when the 2000th copy character image was formed, about 20 black spots having a diameter of 0.2 mm or more were formed per 10 cm ² of the image surface. Example 5 Cylindrical aluminum having a diameter of 60 mm and a length of 258 mm was attached to a lathe, and a depth of 3 μm was set with a cutting tool in the longitudinal direction 1.
Cutting was performed with the cutting edge of the cutting tool while rotating the cylindrical aluminum so that three cutting lines per mm were spirally formed.

Next, this cylindrical aluminum was attached to a milling machine, and two cutting lines were formed in a direction parallel to the longitudinal direction of the cylindrical aluminum at a depth of 3 μm per 1 mm in the circumferential direction.

In this cylindrical aluminum, tapered reflecting surfaces having a width of 1000/3 μm and a height of 5 μm in the longitudinal direction are regularly formed at intervals of 1000/3 μm, and further, in the circumferential direction. Is 5μ with a width of 500μm
Tapered reflecting surfaces having a height of m were regularly formed at every 500 μm pitch.

Next, conductive carbon paint (Fujikura Kasei Co., Ltd.)
100 parts by weight of Dotite) and 50 parts by weight of melamine resin (Super Beckamine, manufactured by Dainippon Ink and Chemicals, Inc.) were mixed with 100 parts by weight of toluene. This solution was applied on a previously cut aluminum cylinder by a dip coating method and then heat-cured at 150 ° C. for 30 minutes to give a film thickness of 4 μm.
m has a conductive layer.

Next, the polyamide resin layer used in Example 1, the charge generation layer and the charge transport layer were sequentially provided on the conductive layer to prepare an electrophotographic photoreceptor.

When this was attached to the laser beam printer used in Example 1 and a similar image was formed, no interference fringe pattern appeared in the entire black image as in Example 1, and 2000 It was found that no black spots were found in the copy character image of the first sheet. Comparative Example 3 The same method as in Example 1 was carried out except that the cylindrical aluminum that had been sandblasted to have an average surface roughness of 3 μm was used in place of the cylindrical aluminum that had been subjected to the cutting process used in Example 5. An image was formed after preparing a comparative electrophotographic photosensitive member. As a result, an interference fringe pattern that is slightly weaker than that of Comparative Example 1 appears in the entire black image, and 2000
0.2 cm diameter per 10 cm ² in the first copy character image
Black spots of mm or more were formed at a rate of 40 or more.

[0058]

As described above, the electrophotographic photosensitive member of the present invention can be used in an electrophotographic printer using a semiconductor laser having a relatively long wavelength (for example, 750 nm or more).
When the coherent light such as a laser beam is used as a light source, it is possible to completely eliminate the interference fringe pattern at the time of image formation, which has been revealed by the conventional method. Can be effectively resolved.

[Brief description of drawings]

FIG. 1 is a perspective view of a conductive substrate used in the present invention.

FIG. 2 is an enlarged sectional view.

FIG. 3A is a sectional view showing an aspect of a conventional electrophotographic photosensitive member, and FIG. 3B is a sectional view showing an aspect of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Linear Protrusion 3 Tapered Reflecting Surface 4, 10 Photoconductive Photosensitive Layer 5 Light Diffusing Surface 6 Conductive Layer 7 Barrier Layer 8 Charge Generation Layer 9 Charge Transport Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masafumi Hisamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hitoshi Toma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Naoto Fujimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-58-162975 (JP, A) JP-A-56-150755 (JP) , A)

Claims (2)

[Claims] 1. A photoreceptor having a coating layer having a photosensitive layer on a cylindrical substrate, wherein the surface of the cylindrical substrate is circumferentially aligned.
The width is 10 μm to 500 μm and the depth is 0.3 μm to 30
It is characterized in that it has grooves of μm in parallel, and the cross section along the width direction of each groove has a regular shape, whereby the film thickness of the coating layer changes regularly. Photoconductor. 2. The photosensitive member according to claim 1, wherein the groove forms a tapered reflecting surface.