JPH09258461A - Production of laminated electrophotographic photreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the formation of a uniform photosensitive layer and to attain the compatibility of the strength to chipping of a film with coatability and the perservable stability of a coating liquid by using a binder resin and specifying the moving speed of a conductive substrate in a vapor vessel of a coating vessel after the bottom end of the conductive substrate parts from the coating liquid after application of a photosensitive layer. SOLUTION: The conductive substrate is parted from the coating vessel and the photosensitive layer is formed of a charge generating layer and a charge transfer layer in the coating applying vessel filled with the coating liquid. In such a case, the binder resin for the charge transfer layer having a viscosity average mol.wt. of 30,000 to 60,000 is used. The moving speed of the conductive substrate in the vapor vessel of the coating applying vessel after the bottom end of the conductive substrate parts from the coating liquid after application of the photosensitive layer is set higher than the moving speed of the conductive substrate at the time of applying the photosensitive layer. Then, the formation of the uniform photosensitive layer is made possible by controlling the drying speed of the coating film without receiving the influence of the variable speed. The compatibility of the strength to chipping of the film by the cleaning stage of a copying machine and the coatability with the preservable stability of the coating liquid is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated electrophotographic photosensitive member, and more particularly to a method for manufacturing a laminated electrophotographic photosensitive member by applying a photosensitive material to a substrate by a dip coating method.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors currently in practical use can be roughly classified into those using an inorganic material and those using an organic material. Typical inorganic photoreceptors include selenium-based ones such as amorphous selenium (a-Se) and amorphous selenium arsenic (a-As ₂ Se ₃ ), dye-sensitized zinc oxide (ZnO), or cadmium sulfide. (Cd
There are those in which S) is dispersed in a binder resin, those in which amorphous silicon (a-Si) is used, and the like. A typical organic photoconductor is 2,4,7-trinitro-
For example, a charge transfer complex of 9-fluorenone (TNF) and poly-N-vinylcarbazole (PVK) is used.

These photoreceptors have many advantages as well as drawbacks. For example, selenium and CdS
The photoconductor using is problematic in heat resistance and storage stability, and has a limitation that it cannot be easily discarded because it has toxicity and must be recovered. ZnO resin-dispersed photoreceptors are almost not used at present because of low sensitivity and lack of durability. The a-Si photoreceptor is
Although it has excellent advantages such as high sensitivity and high printing durability,
There remain problems such as high manufacturing cost due to the complexity of the manufacturing process and image defects due to defects during film formation.

On the other hand, organic photoreceptors have many kinds of organic materials and can be arranged in various ways by synthesis. Therefore, by appropriately selecting them, problems such as storage stability and toxicity can be avoided and low Since it can be manufactured at cost, each company is energetically considering it. However, the organic photoreceptor also has a problem of low sensitivity, and its improvement is being promoted. The PVK-TNF charge transfer complex described above was one of the improvements, but it did not reach sufficient sensitivity.

Therefore, various other sensitizing methods have been proposed, and among them, a layer containing a substance (hereinafter referred to as "charge generating substance") which generates a charge carrier when irradiated with light (hereinafter referred to as "charge generating layer; CGL"). , And a layer mainly composed of a substance that accepts and transports charge carriers generated in the charge generation layer (hereinafter, referred to as “charge transport material”) (hereinafter, referred to as “charge transport layer; CTL”). ) And a laminated type photoconductor (hereinafter referred to as “multilayered electrophotographic photoconductor”) exhibit excellent sensitization property, and therefore, have constituted most of the organic photoconductor constitutions currently put into practical use. There is. Further, it is expected to be the mainstream of photoconductors in the future due to the improvement of durability in recent years.

As a method for producing an electrophotographic photosensitive member using the above organic material, a conductive substrate is dipped in a coating solution containing a photosensitive material as described in JP-A-57-5047. And then withdrawing the substrate from the coating liquid,
A dip coating method for forming a photosensitive layer on a substrate is known,
Since it is simple in terms of equipment and has excellent productivity, it has become the mainstream of the method for producing an organic photoconductor.

At present, the durability of the organic photoconductor is improved, but it is inferior to that of the inorganic type, and further improvement of the durability is expected in the future.

The cause of the poor durability of the organic photoreceptor is
There is a film scraping of the photosensitive layer due to the cleaning process of the copying machine.As the photoconductor becomes thin, the charging property is reduced and streak-shaped image defects occur on the image, and further defects of the photosensitive layer occur, which causes problems. Become.

For the purpose of improving these problems, a method of increasing the film thickness of the photoconductor to reduce the relative amount of film abrasion is disclosed in JP-A-3-56966, JP-A-3-63653, and JP-A-3-63653. JP-A-3-87749, JP-A-3-1113
No. 53, etc.

However, in order to increase the thickness of the photosensitive layer, various problems occur. For example, image unevenness occurs due to defective rising of the film thickness at the upper end of the photoconductor, and the amount of the charge transport layer coating liquid used increases, leading to higher costs. Due to the thick film, residual solvent is generated under the conventional drying conditions, which causes image defects due to long-term use. Further, if the drying temperature is raised for the purpose of eliminating the residual solvent, the organic material will be thermally destroyed and the characteristics of the photoreceptor will be lost. It is also possible to increase the solid content concentration of the charge transport layer coating liquid for the purpose of obtaining a uniform thick film photoreceptor, but in this case, poor dissolution of the organic material and deterioration of the stability of the coating liquid, When the thickness of the charge transport layer is increased, the amount of solvent evaporation increases during air-drying during coating of the charge transport layer, which causes problems such as defective brushing of the coating film.

[0011]

In the case of the conventional dip coating, it is necessary to provide an overflow device for the purpose of preventing the precipitation of the coating solution and keeping the dipping length of the conductive substrate constant. However, in the case of overflow coating, uneven coating occurs due to the turbulent flow of the coating liquid during coating while overflowing. Therefore, in order to satisfy the above conditions, a method of overflowing only when the substrate is immersed and stopping the overflow during coating can be considered. However, according to this method, the unevenness of the coating film due to the turbulent flow of the coating liquid can be eliminated, but due to the sagging during the drying process of the coating film, a difference in film thickness occurs between the upper and lower portions of the photoreceptor in the coating direction.

A method of controlling the coating speed in a coating solution for the purpose of improving these problems is disclosed in JP-A-57-50.
48, JP-A-59-46171, JP-A-6
No. 0-146244, JP-A No. 60-158455, etc. are proposed.

However, when the substrate is changed in speed in the coating liquid,
It is difficult to obtain a uniform coating film because the film thickness changes extremely at the shift point. Further, as shown in FIGS. 22 and 23 (where 51 is a solvent vapor layer, 52 is a coating tank, 53 is a liquid surface of a coating solution, 54 is a coating tank coating lid, 55 is a coating solution, and 56 is an overflow. A receiving tank, 57 is a coating liquid supply port, 58 is a coating liquid returning port, 59 is a coated substrate, and 60 is a coating tank coating lid opening.) A method of controlling the liquid level lowering speed by making the coating tank into a conical shape It is difficult to arrange speed control and it is impossible to support multiple models. Further, since the capacity of the coating tank is large and a large amount of coating liquid is required, there is a problem that the loss of the coating liquid is large and the cost is high.

[0014]

According to a first aspect of the present invention, there is provided a method of manufacturing a laminated electrophotographic photosensitive member, wherein a conductive substrate is immersed in a coating tank filled with a coating solution, and then the conductive substrate is removed from the coating tank. In a method for producing a laminated electrophotographic photoreceptor in which a photosensitive layer is formed from a charge generation layer and a charge transport layer which are separated from each other, a binder resin for a charge transport layer having a viscosity average molecular weight of 30,000 to 60,000 is used. The moving speed of the conductive substrate in the vapor tank of the coating tank after the lower end of the conductive substrate is separated from the coating liquid after coating the photosensitive layer is the moving speed of the conductive substrate during coating of the photosensitive layer. Make it faster.

According to the above manufacturing method, after coating the photosensitive layer,
The lower film thickness of the charge transport layer is thinned. By making the moving speed of the substrate in the solvent vapor layer faster than the moving speed of the substrate during coating, the drying speed of the coating film is controlled to affect the shift. It is possible to form a uniform photosensitive layer without a charge-transporting layer. Also, by setting the viscosity average molecular weight of the binder resin for the charge transport layer to 30,000 or more and 60,000 or less, the film scraping strength in the cleaning process of the copying machine can be improved. In addition, it is possible to achieve both coatability and storage stability of the coating liquid.

According to a second aspect of the present invention, there is provided a method of manufacturing a multi-layer electrophotographic photosensitive member, which comprises lowering a coating liquid level in the coating tank when the conductive substrate and the coating tank are separated from each other when the photosensitive layer is formed. To form a photosensitive layer.

According to the above manufacturing method, by stopping the supply of the coating liquid during the coating of the photosensitive layer and lowering the liquid level in the coating tank, the solvent vapor layer is lengthened and the moving speed in the solvent vapor layer is increased. Since the vapor layer can be effectively used by controlling, a more uniform photosensitive layer can be formed.

According to a third aspect of the present invention, the distance between the opening of the coating lid of the coating tank and the surface of the coating liquid after the photosensitive layer is formed is 30 mm to 500 mm.

According to the above manufacturing method, by suppressing the distance between the opening of the coating tank coating lid and the surface of the coating liquid to be 30 mm or more, it is possible to suppress the coating unevenness in the image area of the photoconductor by 500.
When the thickness is less than or equal to mm, it is possible to suppress the occurrence of coating film defects in the electric field generation layer due to the adverse effect of the solvent.

According to a fourth aspect of the present invention, there is provided a method for producing a laminated electrophotographic photosensitive member, wherein the moving speed of the conductive substrate at the time of dip coating the charge transport layer of the photosensitive layer is 0.8 mm / sec to 4.0 mm /.
sec.

According to the above-mentioned manufacturing method, the coating liquid for the charge transport layer is used, and the substrate moving speed at the time of coating the photosensitive layer is 0.8 m.
By setting m / sec to 4.0 mm / sec, it is possible to make the charge transport layer uniform and to suppress film defects such as brushing in the film drying step.

According to a fifth aspect of the present invention, in the method for producing a laminated electrophotographic photoreceptor, the coating solution for the charge transport layer of the photosensitive layer has a total solid content of 10 to 20 parts by weight and a viscosity of 10 to 20 parts by weight. 100 mpa. s-400 mpa. s.

According to the above manufacturing method, the coating solution for the charge transport layer has a total solid content of 10 to 20 parts by weight,
Moreover, the viscosity is 100 mpa. s-400 mpa. When it is set to s, coatability of the charge transport layer, thickening of the coating solution for the charge transport layer, suppression of poor solubility, and storage stability can be ensured.

In the method of manufacturing a laminated electrophotographic photosensitive member according to claim 6, the dry film thickness of the charge transport layer is 10 μm to 25 μm.
μm.

According to the above-described manufacturing method, by setting the dry film thickness of the charge transport layer to 10 μm to 25 μm, it is possible to make the coating film uniform and suppress the generation of residual solvent in the coating film.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic cross-sectional view showing the moment when the photosensitive layer is applied without lowering the liquid level of the coating liquid and the substrate is separated from the liquid level. In FIG. 1, 1 is a solvent vapor layer and 2 is a solvent vapor layer. , Coating tank, 3 coating surface, 4 coating tank coating lid, 5 coating solution, 6 overflow receiving tank, 7 coating solution supply port, 8 coating solution return port, 9 Is a coated substrate, 10
Is the opening of the coating tank coating lid. FIG. 2 shows the moment when the photosensitive layer was applied while lowering the liquid level of the coating liquid and the substrate was separated from the liquid level of the coating liquid. FIG. 3 shows a coating apparatus of the present embodiment, 11 is a stirring tank, 12 is a liquid feed pump, 13 is an overflow coating tank, 14 is a conductive substrate holding section, 1
Reference numeral 5 is a ball screw for raising and lowering the conductive substrate, 16 is a ball screw driving motor, and 17 is a coating speed control device.

In a coating tank as shown in FIG. 1, for example, a bisazo pigment (chlorodiasi blue) of the following structural formula (Formula 1) 1.
5 parts by weight and butyral resin (made by Union Carbide:
XYGS) 1.5 parts by weight and methyl isobutyl ketone 98
A mixture of 1 part by weight and 8 parts by weight was dispersed with a paint shaker for 8 hours to fill the prepared charge generation layer coating solution. Next, a cylindrical conductive base made of aluminum, whose upper end is hermetically held, is immersed in the coating tank to overflow the coating liquid. When the substrate reaches the desired depth, the immersion is stopped, and then the substrate is drawn out and coated at a constant speed of 5.0 mm / sec to the state shown in FIG. At this time, the coating liquid having a volume larger than that of the substrate to be drawn out from the coating liquid is fed from the supply port at the lower part of the coating tank, and the coating is performed while controlling the liquid level of the coating liquid so as not to decrease. Then, after the substrate was separated from the surface of the coating liquid, the withdrawing speed of the substrate was changed to 2.0 mm / sec, and the substrate was drawn out at a constant speed until the substrate came out of the steam tank to form a charge generation layer on the conductive substrate. When the film thickness of the charge generation layer thus produced was measured with a profilometer (Taylor Hobson: Talysurf), a coating film having a small difference in film thickness between the upper part and the lower part of the coating layer was obtained. . Further, on the charge generation layer, 1 part by weight of a hydrazone compound (4.-diethylaminobenzaldehyde-NN-diphenylhydrazone) represented by the following structural formula (Formula 2) and a polycarbonate resin (supplied by Mitsubishi Gas Chemical Company: Iupilon) ) A mixture of 1 part by weight and 8 parts by weight of dichloromethane was stirred and dissolved, and the prepared coating solution for the charge transport layer was filled in a coating tank at a coating speed of 6.0 mm / sec.
Under the condition that the substrate moving speed in the vapor layer was 2.5 mm / sec, dip coating was performed on the charge generation layer; CGL by the same method as for the charge generation layer to provide the charge transport layer; CTL. Then, the coated photoreceptor was dried with hot air at a drying temperature of 80 ° C. for 1 hour to prepare a function-separated electrophotographic photoreceptor.

An eddy current type film thickness meter (Fisherscope EDDY36
In the same manner as the charge generation layer, a photoreceptor having a small film thickness difference between the upper and lower portions of the photoreceptor was obtained. The photoconductor thus obtained is used as an actual device (S: Sharp Corp .: S).
When it was mounted on F7370) and the image was confirmed, good image characteristics without image unevenness were obtained.

[0030]

Embedded image

[0031]

Embedded image

The results of the film thickness measurement carried out in this example are shown in FIG. 4 (the horizontal axis in the figure is the longitudinal direction (mm) of the photoreceptor, and the vertical axis is
The film thickness (μm) of each coating film is shown. ).

(Example 2) The manufacturing method of Example 2 is the same as Example 1 except that the supply of the coating solution at the time of coating the charge transport layer is stopped and the liquid level in the coating tank is lowered. A laminated electrophotographic photosensitive member was prepared by the same method as in Example 1. The measurement result of the film thickness formed in Example 2 is shown in FIG.

When the laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, good image characteristics without image unevenness were obtained.

(Embodiment 3) In the manufacturing method of Embodiment 3, the speed change after coating the charge transport layer in Embodiment 2 is performed at the speed obtained by the following mathematical formula 1, and otherwise the same as Embodiment 2. A laminated electrophotographic photosensitive member was prepared by the method described in Example 3
FIG. 6 shows the measurement result of the film thickness formed in.

X = Yexp (Zt) number 1 X: moving speed (shift) of the substrate in the vapor layer Y: coating speed Z: 0.013 The laminated electrophotographic photosensitive member thus obtained was used as an example. When the same image confirmation and film thickness confirmation as in 1 were performed, good image characteristics without image unevenness were obtained.

Example 4 The manufacturing method of Example 4 is the same as that of Example 2 except that the distance between the opening of the coating tank cover of Example 2 and the liquid surface after coating the photosensitive layer is 30 mm. A laminated electrophotographic photosensitive member was prepared by the method, and the measurement results of the film thickness formed in Example 4 are shown in FIG.

When the laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, good image characteristics without image unevenness were obtained.

(Example 5) The manufacturing method of Example 5 is the same as that of Example 2 except that the distance between the opening of the coating tank cover of Example 2 and the liquid surface after coating the photosensitive layer is 500 mm. A laminated electrophotographic photosensitive member was prepared by the method, and the measurement result of the film thickness formed in Example 5 is shown in FIG.

The laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, and good image characteristics without image unevenness were obtained.

(Example 6) In the manufacturing method of Example 6, the coating speed of the charge transport layer of Example 1 was set to 3.0 mm / sec, and otherwise the same method as in Example 1 was used. FIG. 9 shows the measurement results of the film thickness of the photoconductor prepared in Example 6.

The laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, and good image characteristics without image unevenness were obtained.

(Example 7) In the manufacturing method of Example 7, the coating speed of the charge transporting layer of Example 1 was set to 0.8 mm / sec, and otherwise the same method as in Example 1 was used. A photoconductor was prepared to obtain a multi-layer electrophotographic photoconductor having a charge transport layer having a thickness of 10 μm. The measurement result of the film thickness formed in Example 7 is shown in FIG.

When the laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, good image characteristics without image unevenness were obtained.

(Embodiment 8) The manufacturing method of Embodiment 8 uses the charge transport material of the charge transport layer coating liquid of Embodiment 1 with 5.0 parts by weight of charge transport material and 90 parts by weight of dichloromethane, and a viscosity of 100 mp.
a. A multilayer electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transporting layer coating solution of s was used, and the measurement results of the film thickness formed in Example 8 are shown in FIG. Indicate.

(Example 9) In the manufacturing method of Example 9, the viscosity average molecular weight of the binder resin for coating the charge transport layer was 60,0.
00, the coating liquid viscosity is 400 mpa. s, the charge transport layer is coated at a coating speed of 0.8 mm / sec, and the moving speed of the substrate in the vapor layer after coating the charge transport layer is 4.5 mm / sec.
A laminated electrophotographic photosensitive member was produced by the same method as in Example 1 except that the time was set to sec, and the measurement result of the film thickness formed in Example 9 is shown in FIG.

The laminated electrophotographic photosensitive member thus obtained was subjected to the same image confirmation and film thickness confirmation as in Example 1, and good image characteristics without image unevenness were obtained.

Comparative Example 1 An electrophotographic photosensitive member was produced by pulling out the conductive substrate at the same coating speed without controlling the speed in the vapor layer as in Example 1.
The image and the film thickness of the thus obtained photoconductor were checked in the same manner as in Example 1. As a result, the film thickness of the coating film was thin below the photoconductor, which caused image unevenness. Good photoconductor characteristics could not be obtained. FIG. 13 shows the measurement result of the film thickness performed in Comparative Example 1.

(Comparative Example 2) The distance between the opening of the coating tank coating lid of Example 4 and the liquid level of the coating liquid after coating the photosensitive layer was 30 mm, but it was set to 20 mm, and other than that, Example 4 was used. A laminated electrophotographic photosensitive member was prepared in the same manner as in 1. and the thus-obtained photosensitive member was subjected to image confirmation and film thickness confirmation in the same manner as in Example 1. Due to insufficient control of the film thickness, uneven density occurred in a part of the image, and good image characteristics could not be obtained. FIG. 14 shows the measurement result of the film thickness performed in this Comparative Example 2.

(Comparative Example 3) The distance between the opening of the coating tank coating lid of Example 5 and the liquid level of the coating liquid after coating the photosensitive layer was 500 mm, but was 600 mm, and other than that, Example 5 was used. A laminated electrophotographic photosensitive member was prepared in the same manner as in 1. and the thus obtained photosensitive member was subjected to image confirmation and film thickness confirmation in the same manner as in Example 1. The charge generation layer was adversely affected by solvent vapor. Results in a rough and rough image, and the film thickness becomes thin at the upper and lower portions of the charge transport layer, resulting in uneven density, and good image characteristics cannot be obtained. FIG. 15 shows the measurement result of the film thickness performed in Comparative Example 3.

(Comparative Example 4) The coating speed of the charge transport layer of Example 1 was 4.0 mm / sec, but the coating speed was 0.7 mm / sec.
A laminated electrophotographic photosensitive member was prepared in the same manner as in 1. and the thus obtained photosensitive member was subjected to image confirmation and film thickness confirmation in the same manner as in Example 1. The charge generation layer was adversely affected by solvent vapor. Was a rough and rough image, and the average film thickness of the charge transport layer was as thin as 9 μm and there was no contrast, and good image characteristics could not be obtained. FIG. 16 shows the measurement result of the film thickness performed in Comparative Example 4.

(Comparative Example 5) The coating speed of the charge transport layer in Example 1 was 4.0 mm / sec, while the coating speed was 4.2 mm / sec.
A laminated electrophotographic photosensitive member was prepared by the same method as described in (1), and the thus obtained photosensitive member was subjected to image confirmation and film thickness confirmation in the same manner as in Example 1. As a result, the upper portion of the dried charge transport layer was confirmed. In the lower part, the film thickness becomes thin, uneven density occurs in the image, and brushing occurs in the lower part, which causes uneven image, and good image characteristics cannot be obtained. FIG. 17 shows the measurement result of the film thickness performed in this Comparative Example 5.

(Comparative Example 6) The binder resin for the charge transport layer used in Example 1 had a viscosity average molecular weight of 30,000, but was 25,000, and the viscosity liquid viscosity was 90 mp.
a. s, except that a laminated electrophotographic photosensitive member was prepared by the same method as in Example 1, and the image and film thickness of the thus obtained photosensitive member were confirmed in the same manner as in Example 1. However, the average film thickness of the charge transport layer after drying was 8 μm, and an image with no contrast was obtained, and good image characteristics were not obtained. Although the coating speed was increased in order to increase the film thickness, defective rising of the upper film thickness of the photoconductor, brushing, etc. occurred, and good image characteristics could not be obtained. FIG. 18 shows the measurement result of the film thickness performed in this Comparative Example 6.

(Comparative Example 7) The binder resin for the charge transport layer used in Example 1 had a viscosity average molecular weight of 30,000, but was 70,000, and the viscosity liquid viscosity was 480 mp.
a. s, except that a laminated electrophotographic photosensitive member was prepared by the same method as in Example 1, and the image and film thickness of the thus obtained photosensitive member were confirmed in the same manner as in Example 1. The average film thickness of the charge transport layer after drying is 49 μm, and after the bubbles in the coating film due to the poor bubble escape of the coating solution for the charge transport layer, the film thickness of the charge transport layer causes the brushing at the lower part of the photoreceptor to cause an image defect. became. Further, in order to make the film thickness 25 μm, the coating speed of the charge transport layer is extremely slow at 0.25 mm / sa, and the surface of the charge generation layer is rough due to the bad influence of the solvent vapor layer and the film thickness is insufficient at the lower part of the photoreceptor. However, good image characteristics cannot be obtained. FIG. 19 shows the measurement result of the film thickness performed in this Comparative Example 7.

Comparative Example 8 9 parts by weight of the coating solution for the charge transport layer of Example 1 having a total solid content of 20 parts by weight and a coating solution viscosity of 96 mpa. s, except that a laminated electrophotographic photosensitive member was prepared by the same method as in Example 1, and the image and film thickness of the thus obtained photosensitive member were confirmed in the same manner as in Example 1. However, the average film thickness of the charge transport layer after drying was 9 μm, and good image characteristics were not obtained. Further, in order to make the film thickness 25 μm, the coating speed of the charge transport layer becomes as high as 10 mm / sa, insufficient rising of the upper part of the photoconductor and brushing over the entire surface of the photoconductor, and good image characteristics can be obtained. I couldn't do it. FIG. 20 shows the measurement result of the film thickness performed in this Comparative Example 8.

Comparative Example 9 The total solid content of the charge transport layer coating solution of Example 1 was 20 parts by weight, but 25
Parts by weight, the viscosity of the coating liquid is 425 mpa. s, except that a laminated electrophotographic photosensitive member was prepared by the same method as in Example 1, and the image and film thickness of the thus obtained photosensitive member were confirmed in the same manner as in Example 1. The average film thickness of the charge transport layer after drying is 35 μm, and after the bubbles in the coating film due to the poor bubble escape of the coating solution for the charge transport layer, the film thickness of the charge transport layer causes brushing in the lower part of the photoconductor to cause an image defect. became.
Further, in order to make the film thickness 25 μm, the coating speed of the charge transport layer was 2.2 mm / sa, and a relatively uniform photosensitive layer was obtained, but insoluble matter was generated in the coating solution because the fixed concentration was large. However, good image characteristics were not obtained because white spot defects occurred on the image. FIG. 20 shows the measurement result of the film thickness performed in this Comparative Example 9.

[0057]

According to the method of manufacturing a laminated electrophotographic photosensitive member of claim 1, the substrate is moved at a moving speed in a solvent vapor layer where the lower film thickness of the charge transport layer becomes thinner after coating the photosensitive layer. It is possible to form a uniform photosensitive layer without being affected by the speed change by controlling the drying speed of the coating film by making the moving speed higher than the moving speed of the substrate, and the binder resin for the charge transport layer. Viscosity average molecular weight of 30,000 or more 6
When the amount is less than or equal to 10,000, the film scraping strength in the cleaning process of the copying machine and the coatability and the storage stability of the coating liquid can be made compatible.

According to the method for producing a laminated electrophotographic photosensitive member of claim 2, the supply of the coating liquid during the coating of the photosensitive layer is stopped and the liquid level in the coating tank is lowered to lengthen the solvent vapor layer. By controlling the moving speed in the solvent vapor layer, the vapor layer can be effectively utilized, so that a more uniform photosensitive layer can be formed.

According to the method for producing a multi-layer type electrophotographic photosensitive member of claim 3, the image area below the photosensitive layer is set by setting the distance between the opening of the coating tank coating lid and the liquid surface of the coating liquid to be 30 mm or more. By suppressing the coating unevenness in the inside to 500 mm or less, it is possible to suppress the coating film defect of the electric field generation layer and the thinning of the lower portion of the charge transport layer due to the adverse effect of the solvent.

According to the method for producing a multi-layer type electrophotographic photoconductor of claim 4, the coating solution for the charge transport layer is used, and the substrate moving speed at the time of coating the photosensitive layer is 0.8 mm / sec to 4.0 m.
By setting m / sec, it is possible to make uniform the film of the charge transport layer and suppress film defects such as brushing in the film drying step.

According to the method for producing a multi-layer type electrophotographic photosensitive member of claim 5, the coating solution for the charge transport layer has a total solid content concentration of 10 to 20 parts by weight and a viscosity of 100 m.
pa. s-400 mpa. When it is set to s, coatability of the charge transport layer, thickening of the coating solution for the charge transport layer, suppression of poor solubility, and storage stability can be ensured.

According to the method for producing a multi-layer electrophotographic photosensitive member of claim 6, the dry thickness of the charge transport layer is 10 μm to 2 μm.
By setting the thickness to 5 μm, it is possible to make the coating film uniform and suppress the generation of residual solvent in the coating film.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a coating apparatus according to an embodiment of the present invention (when a photosensitive layer is coated without lowering the coating liquid level).

FIG. 2 is a schematic cross-sectional view of a coating apparatus according to an embodiment of the present invention (when coating a photosensitive layer while lowering the coating liquid level).

FIG. 3 is a schematic cross-sectional view of a coating device and a substrate holding / lifting device according to an embodiment of the present invention.

FIG. 4 is a longitudinal direction length and CG of a photoconductor in Example 1.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 5 is a longitudinal length and CG of a photoconductor in Example 2.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 6 is the longitudinal length and CG of the photoconductor in Example 3.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 7 is the longitudinal length and CG of the photoconductor in Example 4.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 8 is a longitudinal length and CG of a photoconductor in Example 5.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 9 is a longitudinal length and CG of a photoconductor in Example 6.
It is a figure showing the relationship with the thickness of L * CTL.

FIG. 10 is the longitudinal length and C of the photoconductor in Example 7.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 11 is the longitudinal length of the photosensitive member and C in Example 8.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 12 is the longitudinal length and C of the photoconductor in Example 9.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 13 is the longitudinal length of the photoconductor and C in Comparative Example 1.
It is a figure showing the relationship with the thickness of GL * CTL.

14 is a longitudinal length of the photoconductor and C in Comparative Example 2. FIG.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 15 is a longitudinal length of the photosensitive member and C in Comparative Example 3.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 16 is the longitudinal length and C of the photoconductor in Comparative Example 4.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 17 is the longitudinal length of the photoconductor and C in Comparative Example 5.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 18 is a longitudinal length of the photoconductor and C in Comparative Example 6.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 19 is the longitudinal length of the photoconductor and C in Comparative Example 7.
It is a figure showing the relationship with the thickness of GL * CTL.

20 is the longitudinal length and C of the photoconductor in Comparative Example 8. FIG.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 21 is the longitudinal length of the photoconductor and C in Comparative Example 9.
It is a figure showing the relationship with the thickness of GL * CTL.

FIG. 22 shows a coating device used in a conventional method for manufacturing a photoreceptor.

FIG. 23 is a coating device used in a conventional method for manufacturing a photoreceptor.

[Explanation of symbols]

 1 Solvent Vapor Layer 2 Coating Tank 3 Liquid Level of Coating Liquid 4 Coating Tank Coating Lid 5 Coating Liquid 6 Overflow Receiving Tank 7 Coating Liquid Supply Port 8 Coating Liquid Return Port 9 Coating Substrate 10 Coating Tank Coating Lid Opening 11 Stirring Tank 12 Liquid feed pump 13 Overflow type coating tank 14 Conductive substrate holding section 15 Conductive substrate lifting ball screw 16 Ball screw drive motor 17 Coating speed control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryuhiro Morita 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Sayaka Uesugi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Rikiya Matsuo 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture

Claims (6)

[Claims] 1. A multi-layer electrophotography in which a conductive substrate is immersed in a coating tank filled with a coating solution, and then the conductive substrate is separated from the coating tank to form a photosensitive layer from a charge generation layer and a charge transport layer. In the method for producing a photoreceptor, a binder resin for a charge transport layer having a viscosity average molecular weight of 30,000 to 60,000 is used, and after the photosensitive layer is coated, the lower end of the conductive substrate is separated from the coating solution. 2. The method for producing a laminated electrophotographic photosensitive member, wherein the moving speed of the conductive substrate in the vapor tank of the coating tank is set to be higher than the moving speed of the conductive substrate at the time of coating the photosensitive layer. 2. The photosensitive layer is formed by lowering the level of the coating liquid in the coating tank when separating the conductive substrate from the coating tank during the formation of the photosensitive layer. 1. The method for producing a laminated electrophotographic photosensitive member according to 1. 3. The distance between the coating lid opening of the coating tank and the liquid surface of the coating liquid after forming the photosensitive layer is 30 mm to 500 mm.
The method for manufacturing a laminated electrophotographic photosensitive member according to claim 1, wherein 4. The moving speed of the conductive substrate during dip coating of the charge transport layer of the photosensitive layer is 0.8 mm / sec to 4.0 m.
2. The method for manufacturing a laminated electrophotographic photosensitive member according to claim 1, wherein m / sec. 5. The coating solution for the charge transport layer of the photosensitive layer has a total solid content concentration of 10 to 20 parts by weight and a viscosity of 100 mPa.s. s-400 mpa. 2. The method for producing a laminated electrophotographic photosensitive member according to claim 1, wherein S is s. 6. The dry film thickness of the charge transport layer is from 10 μm to
The method for producing a laminated electrophotographic photosensitive member according to claim 1, wherein the thickness is 25 μm.