KR20030019253A - An electrophotographic photoconductor and production method of the electrophotographic photoconductor - Google Patents

Abstract

PURPOSE: An electronic photograph photoreceptor and its preparation method are provided, to reduce the ununiformity of concentration and thickness of a coating remarkably for improving the uniformity of a coating and preventing the unevenness the outermost coating layer. CONSTITUTION: The electronic photograph photoreceptor is prepared by layering the photoreceptor material layers comprising (n) layer to the surface of a cylindrical body. The (n-1)-th layer and the (n-2)-th layer are formed by dip-coating and the n-th layer is formed by spray-coating with the condition that the viscosity of the (n-1)-th layer coating solution is greater than that of the (n-2)-th layer coating solution or the n-th layer coating solution. Preferably the viscosity of the (n-2)-th layer coating solution is 6.0 cps or less, that of the (n-2)-th layer coating solution is 150-450 cps, and that of n-th layer coating solution is 3.0-10.0 cps. Preferably the (n-2)-th layer is a charge generation layer, the (n-1)-th layer is a charge transport layer, and the (n)-th layer is a surface protection layer.

Description

The electrophotographic photosensitive member and the manufacturing method of the electrophotographic photosensitive member {AN ELECTROPHOTOGRAPHIC PHOTOCONDUCTOR AND PRODUCTION METHOD OF THE ELECTROPHOTOGRAPHIC PHOTOCONDUCTOR}

TECHNICAL FIELD This invention relates to an electrophotographic photosensitive member and its manufacturing method. Specifically, It is related with the electrophotographic photosensitive member which forms a photosensitive layer, a protective layer, etc. on a cylindrical base by combining immersion coating and spray coating, and its manufacturing method.

Recently, there is a remarkable development in the information processing system using the electrophotographic method. In particular, laser printers that convert information into digital signals and record information by light have remarkable improvements in print quality and reliability. Furthermore, it is applied to the laser printer which can perform full color printing by the convergence with these speed-up technologies.

The photoconductor mounted in electrophotographic apparatuses such as an electrophotographic printer, a copier, and a facsimile is mainly an amorphous silicon photoconductor by vapor phase growth (CVD) method, a selenium photoconductor by vacuum deposition method, and There are organic photoreceptors typified by crude and phthalocyanine entrances, and organic photoreceptors are most widely used for reasons such as wide selection of materials.

The electrophotographic photosensitive member is produced as a cylindrical photosensitive member and an endless belt photosensitive member corresponding to the structure, mechanism, and the like of the electrophotographic apparatus. Here, as the cylindrical photosensitive member, (1) a single photosensitive layer containing a charge generating material and a charge transporting material through a bottom layer provided as necessary on a cylindrical conductive base (hereinafter simply referred to as [gas] or [cylindrical base]). A charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are provided on the photosensitive layer of (1) above, (2) providing a protective layer on the photosensitive layer of (1) above, and (3) a bottom layer provided as necessary on a cylindrical substrate. It is known to laminate sequentially and to provide a protective layer on the laminated photosensitive member of (4) above (the photosensitive layer includes an inverse layer photosensitive member consisting of a charge transport layer / charge generating layer). An electrophotographic photosensitive member which is composed of a gas / bottom layer, a charge generating layer, a charge transport layer, and a protective layer having high reliability in strength and the like is widely used.

Such an electrophotographic photosensitive member is generally formed on a cylindrical substrate by using an immersion coating method, a spraying method, or the like, of a photosensitive material layer (bottom layer, photosensitive layer, surface protective layer, etc.). In particular, the immersion coating method is most widely used because of the ease of photoreceptor production, high productivity, and low equipment and cost.

As an actual immersion coating method, a container (immersion coating container) containing a coating liquid of a photoconductor material and a cylindrical gas are moved relative to each other so that the cylindrical gas is immersed in the coating liquid in the coating liquid container and then pulled up, and then the drawn cylindrical gas is stopped. A method of preliminary drying (natural drying), followed by complete drying by oven drying or the like has been adopted. Natural drying here means that the solvent in a coating liquid vaporizes (atmosphere drying) after apply | coating a coating liquid to gas, and before putting into a dryer.

By the way, this immersion coating method is suitable for mass production because several photosensitive substrates can be immersed at a time, but in order to manufacture an electrophotographic photosensitive member having a uniform thickness of the coating film within a short time, it can usually be quickly dried as a solvent of the coating liquid. If a solvent is used, and such a solvent is used, the coating liquid adhering to the cylindrical gas can be dried quickly to solidify within a short time, but it is weak around the product from the time of immersion and then to natural drying. Even with one air flow, the flow of solvent evaporation caused by this flow causes thickness irregularities in the coating film to be formed.

When such a photosensitive member is used, problems such as image unevenness, white spots, and stains caused by toner adhesion are caused.

Moreover, depending on the photosensitive material material layer, the pigment particle dispersed in a solvent has a big influence on the coating film state and the photosensitive member characteristic of a coating surface by the solvent used and their dispersibility. In particular, the pigment particles on the coating film in the dispersion liquid or immediately after coating cause interaction between the particles due to the evaporation rate of the solvent, the dry state, the temperature, the humidity, and the like, and as a result, unevenness occurs in the coating film. Compared to a black and white printer mainly composed of characters, this effect is particularly large in a full color printer in which an image is mainly used. The color unevenness appears directly on the image or lowers uniformity of dislocations, which is a major cause of image deterioration.

In view of the above, various methods have been conventionally devised in order not to cause light and light unevenness or thickness unevenness in the coating film.

For example, there is a method in which a hood is applied to an outer circumferential surface of a cylindrical gas and the coating liquid is applied during immersion coating. In this method, a method of discharging the solvent vapor from the side surface under the hood has been proposed, and a cylindrical hood having a hole around the lower end is provided on the immersion coating container to prevent brushing by diluting the windshield and the evaporation solvent. The coating film formation method characterized by the above is disclosed (for example, Unexamined-Japanese-Patent No. 59-42060). However, this method has a problem that film thickness nonuniformity occurs because wind blows from the hole and directly hits the coating film.

In addition, there is a method of forming a coating film for installing a stretchable or vertically movable hood on the gas holding device and covering the gas with the hood and immersing the gas, and controlling the vapor concentration by defining the size of the hood for the gas ( Japanese Patent Laid-Open No. 7-104488), this method has a problem that if the vapor is not leaked out, the concentration becomes too high and the coating film is dripping.

Moreover, the coating apparatus WHEREIN: The apparatus for ensuring a vapor layer in the upper part of coating liquid is also known.

For example, the cover provided with the hole which can insert an electroconductive gas covered on the upper surface of the base plate which makes the height of the vapor layer of the solvent in the coating liquid which arises on the liquid surface of an immersion container 30 mm or less, and surrounds the outer peripheral surface of the immersion container. The coating film forming apparatus (Japanese Patent Laid-Open No. H5-337430), which has a depth of 30 mm or less and reduces the coating film nonuniformity, is provided with a detachable upper blocking plate and a side plate. And a coating film forming apparatus (Japanese Patent Laid-Open No. 7-144164) and the like, which provide a separation drive function to eliminate coating unevenness during immersion coating.

Furthermore, the thickness of the film without any coating film unevenness is passed through a coating aid provided with a function of removing the solvent vapor from the surrounding coating film at evenly spaced intervals near the upper surface of the coating liquid. Coating film forming apparatus (Japanese Patent Laid-Open No. 9-114110), which is capable of forming a uniform charge generating layer, or an accommodating portion of a solvent, which is a coating component, on an upper portion of an application container, or a separate solvent accommodating portion solvent The vapor supply passage is communicated with the upper part of the coating container to suppress the vapor of the solvent to prevent the viscosity of the paint from rising. Also, a window having a plurality of the same shape and the same area is provided on the photosensitive liquid level of the coating container, and the floating liquid level is floated. And a coating film forming apparatus (Japanese Patent Laid-Open No. 6-123989) characterized by preventing the film thickness fluctuation.

However, it is difficult to eliminate the coating unevenness in any of the above devices.

Moreover, in order to solve the said problem, the combination of the following coating methods is also proposed.

For example, in the coating film formation method which forms the layer provided with two or more types of layers by two or more types of application methods, it is a spray coating method or one type method which is a beam type coating method, an immersion coating method, or an ultrasonic atomization coating method. Two or more types of layer forming method (Japanese Patent Laid-Open No. 2-205855) including a charge generating layer and a charge transporting layer by another one type of phosphorus, and a coating film forming method of coating two or more kinds of paints separately on a coating object The coating film forming method (Japanese Patent Laid-Open No. 2-205856), and at least two spray coatings or immersion coatings and at least two spray coating or immersion coatings, wherein the coating start positions are different from each other, and the coating method is spray coating and beam coating. Although the coating film formation method (Japanese Unexamined Patent Publication No. 5-72759) etc. which form two layers of charge transport layers by one spray coating are also known, Be anything not sufficient enough not improve the coating non-uniformity, and also the non-uniformity and film thickness variation in the coating film formed on the lower level occurs on the top layer before the coating film is formed.

In addition, the expansion hood is installed in the gas holding device, and the substrate is immersed and coated while the gas is covered with the hood, and then air is introduced into the hood to prevent brushing by rapidly evaporating the solvent of the coating liquid on the object to be coated (Japan Japanese Patent Application Laid-Open No. 63-78) and adjusting a vapor concentration inside the hood to satisfy any relation by providing a cylindrical hood having a hole (Japanese Patent Laid-Open Publication No. 60-110378) and the like are also known. It is difficult to eliminate film nonuniformity or change in film thickness.

On the other hand, in addition to the immersion coating method, the spray coating method is also used for photosensitive member manufacture. The spray coating method is advantageous in that it is possible to form less change between layers and melting of the lower layer even with the same solvent-based coating liquid, but drying of the forming coating layer is not necessary every time the layer is formed, That is, after forming a last layer, what can be dried at one time is mentioned. Moreover, there also exists an advantage that a coating film can be formed with a small amount of coating liquid and occupies little space.

However, there is also a problem, for example, it is difficult to uniformly form the coating film compared to the immersion coating method, and if the proper coating liquid or the proper spraying conditions are required and these are neglected, the coated surface partially adheres to the coating liquid, or vice versa. There is a problem that a small portion occurs everywhere, causing non-uniformity of the coating film forming film.

In addition, in the organic electrophotographic photosensitive member, it is preferable to provide a protective layer on the uppermost layer of the photosensitive member in order to enhance durability, but the total thickness cannot be increased only by the protective layer due to the decrease in capacitance in the electrostatic characteristic value. If the photosensitive layer is to be formed by laminating the charge generating layer / charge transporting layer, it is necessary to make the thickness of the charge transporting layer and the protective layer applied to the same thickness as that of the conventional charge transporting layer. In order to maintain the sensitivity, it is not preferable to make the protective layer too thick.

Therefore, it is necessary to apply | coat a protective layer uniformly within 10.0 micrometers as thin as possible, Preferably it is in the range of 3.0-8.0 micrometers.

In addition, when the protective layer is thinner, the unevenness of the charge transporting layer is preferably less because the unevenness of the charge transporting layer underneath is easily affected. However, even if the above-described methods are combined, both problems cannot be sufficiently solved.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member in which the unevenness of the coating film and the thickness unevenness are reduced to the maximum, thereby improving the unevenness of the photosensitive member material layer and improving the film uniformity, and a manufacturing method thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which showed typically the structure before and behind application | coating of the immersion apparatus used by this invention.

2 is a diagram schematically showing a configuration of an immersion state of the immersion apparatus used in the present invention.

3 is a diagram schematically showing a configuration of a spray device of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: stretch hood

2: support member

3: cylindrical gas

4: lifting screw

5: lifting motor

6: coating container

7: coating liquid

8: coating container cover

9: elastic hood upper mounting portion

10: photosensitive gas start portion

11: gas jig holding plate

12: the bottom of the stretch hood

13: cover member

14: solvent vapor generation suppression plate

L1: Height of the opening of the upper end of the telescopic hood

L2: Bottom height of telescopic hood

T1: Steam Leak Prevention Unit

15: photosensitive member

16: rotating motor

17 gun for spray application

18: operating range of the spray coating gun

19: distance between the workpiece and the spray gun

As a result of newly examining the manufacturing method of an electrophotographic photosensitive member, when the n-type photosensitive material material layer is formed on a cylindrical base | substrate from the same solvent system coating liquid used for formation of each layer of photosensitive material layers, The formation of the nth layer (final layer, ie the top layer) is advantageously by spray application, and layers other than this nth layer, i.e., the n-1th layer just below the nth layer, the nth-2 below The layer, and further, the n-3 layer and the like below may be formed by immersion coating, and in this case, the viscosity of the n-1th layer coating liquid is determined by the viscosity of the n-2th layer coating liquid and the nth layer coating liquid. It was found that when the layer is made larger, the unevenness, which is a problem of the dip coating method, can be eliminated, and the unevenness, which is a problem of the spray coating method, can be eliminated and a good coating layer can be obtained. The present invention has been made based on this finding.

In addition, although the layer structure of an electrophotographic photosensitive member is as above-mentioned, the relationship between these and an nth layer, an n-1th layer, an n-2th layer, an n-3 layer, etc. has a layer structure of the photoconductor, for example, gas / In the bottom layer / charge generation layer / charge transport layer / surface protection layer, the nth layer is the surface protection layer, the n-1th layer is the charge transport layer, the n-2th layer is the charge generation layer, and the n-3rd layer is the bottom layer In the case where the photosensitive member has a layer structure of gas / bottom layer / single layer photosensitive layer / surface protective layer, the nth layer is the surface protective layer, the n-1th layer is the single layer photosensitive layer, and the n-2th layer is the bottom layer.

According to the inventors' consideration, the photoconductor has the most preferred layer configuration of gas / bottom layer / charge generating layer / charge transporting layer / surface protective layer, and the thickness of the layer is charge generating layer <bottom layer ≤ protective layer <charge transporting layer. It is preferable that the total film thickness laminated with respect to the thickness of the cylindrical gas is 1: 1/15 to 1: 1: 1, so that the charge transport layer formed by the immersion coating method is applied to the surface layer of the surface protective layer. It will affect the uniformity.

According to this invention, following (1)-(6) is provided.

(1) An electrophotographic photosensitive member formed by laminating an n-layer photosensitive member material layer on the surface of a cylindrical substrate, and a method of manufacturing the electrophotographic photosensitive member, wherein the viscosity of the coating liquid of the n-1-1th layer Under the condition that the coating liquid and the coating liquid of the n-th layer are larger than any viscosity, an immersion coating apparatus including an immersion coating container having a solvent vapor leakage preventing portion at least on the outer circumferential wall and an elastic hood surrounding the side of the cylindrical gas is used. The n-th layer and the n-th layer are formed by immersion coating, and the n-th layer is formed by spray coating, The electrophotographic photosensitive member and its manufacturing method characterized by the above-mentioned.

(2) The viscosity of the coating liquid of n-th layer is 6.0 cps or less, the viscosity of the coating liquid of n-th layer is 150-450 cps, and the viscosity of the coating liquid of n-th layer is 3.0- It is 10.0 cps or less, The electrophotographic photosensitive member and its manufacturing method.

(3) The solvent according to claim 1, wherein the solvent of the coating liquid of the n-th layer has at least one kind of solvent used in the coating liquid of the n-th layer and a boiling point higher than the highest boiling point of the solvent. It is comprised by the electrophotographic photosensitive member and its manufacturing method.

(4) The electrophotographic photosensitive member according to claim 3, wherein the difference in boiling point is 65 to 91 ° C.

(5) The electrophotographic photoconductor according to claim 3, wherein the same solvent as used in the coating liquid of the n-1 layer occupying the whole solvent of the coating liquid of the nth layer is 60 to 90% by weight. Its manufacturing method.

(6) The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the n-2th layer is a charge generating layer, the n-1th layer is a charge transporting layer, and the nth layer is a surface protective layer. And a method for producing the same.

Example

Hereinafter, the present invention will be described in more detail.

As mentioned above, the electrophotographic formation of the nth layer used as an uppermost layer by the spray coating method, and the formation of the other layer (n-1st layer, n-2nd layer ...) by the immersion coating method is carried out. In the method for producing a photoconductor, the immersion coating is performed under the conditions of the viscosity of the n-1 layer coating liquid> the viscosity of the n-2 layer coating liquid, and the viscosity of the n-1 layer coating liquid> the viscosity of the n layer coating liquid. Is carried out by further using an immersion coating apparatus provided with an application container provided with a solvent vapor leakage preventing portion and an elastic hood. By applying in this way, the uniformity | coating of a surface layer and the uneven | corrugated reduction in spray coating can be performed simultaneously.

When the viscosity of each layer coating liquid deviates from the said conditions, a layer will not be formed satisfactorily for reasons, such as a coating nonuniformity and a coating film being nonuniform. In the present invention, the viscosity of the n-2 layer coating liquid is 6.0 cps or less, preferably 3.0 to 5.0 cps, the viscosity of the n-1 layer coating liquid is 150 to 450 cps, preferably 180 to 230 cps, The viscosity of the nth layer coating liquid is 3.0-10.0 cps, Preferably it is 3.0-5.0 cps. By using the coating liquid having such a liquid viscosity, the coating film formed by the immersion coating, in particular, does not easily cause leveling of the coating liquid during natural drying, thereby forming a more uniform film quality.

The coating film uniformity in the immersion method is judged by time and machine after completion of immersion coating and drying.

The conditions of the machine were coated on a conductive support, dried, and measured by an eddy current type film thickness gauge (Fisher Co., Ltd., Fischer Corp. MMS). A total of eight points were measured at intervals, and the coating film uniformity was judged by the difference between the maximum value and the minimum value.

Visually, the average criterion is 3 with 5 levels of evaluation, and the larger the value, the higher the evaluation.

Similarly, the unevenness of the coating film by the spray method is carried out in eight places in the circumferential direction and the longitudinal direction, respectively, and the average value is the film thickness, and the difference between the maximum and minimum values is measured.

In the present invention, furthermore, the solvent of the coating liquid used in the nth layer is a solvent having at least one kind of the coating liquid solvent used in the n-1th layer and having a boiling point higher than the highest boiling point in the solvent (high boiling point solvent). ), The coating uniformity and the prevention of unevenness can be further improved.

As for the difference of a boiling point here, about 65-91 degreeC is suitable. If there is no difference in boiling point, the solvent volatilizes before the coating film becomes smooth, and there is no effect. On the contrary, the volatilization of the solvent in the formed coating film is delayed, which causes the flow unevenness due to the sagging of the coating film. Specific examples of the high boiling point solvent include cyclohexanol, cyclohexanone, cyclopentanol, and the like.

Moreover, among the solvents used for the nth layer coating liquid, the same solvent as the solvent of an n-1th layer coating liquid is apply | coated by mix | blending in at least 60 weight% or more and 90 weight% or less, Preferably it is 70 weight%-80 weight%. Uniformity of the film and prevention of irregularities can be more effectively performed. When less than 60 weight%, the volatilization of the solvent in a formed coating film will become slow, and flow nonuniformity will arise by the coating liquid dripping of a coating film, and when more than 90 weight%, a solvent will volatilize before a coating film becomes smooth, and there will be no effect.

Moreover, by using such a solvent, the sprayed coating liquid can be naturally dried before leveling or hardly dried, thereby minimizing problems such as flow unevenness, sagging of the coating liquid, dust sticking, and the like.

Subsequently, the coating apparatus used for immersion coating used for this invention is demonstrated using drawing.

BRIEF DESCRIPTION OF THE DRAWINGS Although the structure of the coating device used for this invention is shown typically, it is a figure which shows the state in the natural drying before and after apply | coating a coating liquid to a cylindrical base body.

There is a gap of the height L1 (the height of the opening of the upper end of the elastic hood 1) between the gas jig holding plate 11 and the elastic hood upper mounting portion 9. There is a gap (height at the lower end of the stretchable hood 1) of height L2 between the application vessel lid 8 and the stretchable hood 1.

2 is a view showing a state in which the cylindrical gas is immersed in the coating liquid.

The reason for providing height clearance L1, L2 is as follows. When neither L1 nor L2 is provided, the coating film near the L2 side is rough or coating nonuniformity is large, and the film thickness on the L1 side tends to be thin. When setting only L1, the coating film of L1 side vicinity and a lower end side becomes rough, or a coating nonuniformity arises. In addition, when setting only L2, the airflow of a peripheral part will become turbulent and a roughening of a coating film will arise. For this reason, by setting L1 and L2, the airflow does not become turbulent with respect to the vertical movement in immersion coating, so that the coating film roughness and coating unevenness can be suppressed.

As for L1 and L2, the range of 5-20 mm is suitable for all.

The elastic hood 1 is fixed to the base jig holding plate 11 via the support member 2 disposed therein. The base jig holding plate 11 is coupled to the lifting motor 5 via the lifting screw 4. When the lifting motor 5 is driven in a predetermined direction, the lifting screw 4 rotates in the corresponding direction, and the base jig holding plate 11 is raised or lowered in accordance with the rotational direction thereof. The stretchable hood 1 also includes a cover member 13 made of a plurality of components to be retractable / extensible. The stretchable hood 1 is moved from the state of FIG. 1 (non-immersed state or hood stretched state) to the state of FIG. 2 (immersed state or hood retracted state) when the cover member 13 contracts so that the lower end of the support member 2 The cylindrical gas 3 bonded to the plate 3 moves in the form of being immersed into the coating liquid 7.

Then, when the lower end of the stretchable hood 1 reaches the application vessel lid 8 while approaching the solvent vapor leakage preventing portion T1 of the application vessel, the elastic hood 1 gradually folds or starts to contract. When the stretchable hood 1 is folded or contracted, the stretchable hood 1 is structured to be folded inside the member of the stretchable hood immediately above. In FIG. 1 and FIG. 2, although it is a structure folded inward, it may be a structure folded inward.

The stretchable hood is not limited to one having a structure in which the member is folded inward or outward in sequence, and for example, the entire hood may be in a stretchable form.

In particular, when the hood is in an elastic form, it is preferable that the distance between the convex tip of the elastic part and the base is maintained without being skewed when folded. In this sense, by attaching a magnet to the lower end of the elastic portion or by applying a magnetic force to the cover of the coating container may be carried out a folding operation. It is also possible to use a frame in which the frame is helically covered like a spring.

As the material of the stretchable hood 1, metals having high solvent resistance such as aluminum and stainless steel, resins having high solvent resistance such as nylon, poly fluoride ethylene, polycarbonate, polyethylene, polypropylene, glass, rubber and the like can be used.

The design of the height of the hood can cover the support member 2 and the cylindrical body 3 in the hood elongated state shown in FIG. 1, further covering only the support member 2 in the hood retracted state shown in FIG. 2. , The entirety of the cylindrical base 3 is to be completely immersed in the coating liquid 7 in the coating container 6. This height is changed by the total length of the cylindrical body 3 or the length of the support member 2.

As shown in FIG. 2, the stretchable hood 1 immerses the cylindrical gas 3 in the coating liquid 7 contained in the coating container 6 in a contracted state, and then leaks solvent vapor of the coating container in an extended state. The cylindrical body 3 is pulled up through the prevention part T1.

The solvent vapor leak prevention part T1 is provided so that the solvent vapor of the coating liquid 7 may not be disturbed when the cylindrical gas 3 is immersed and lowered in the coating container 6, and the excess coating liquid is applied to the coating container 6. Since the solvent vapor floating on the top of the coating liquid is disturbed due to the air pressure generated by returning inside, it is possible to prevent the coating irregularity and the film thickness unevenness from occurring. Coating unevenness and film thickness unevenness can be suppressed to the minimum.

The shape, particularly the height, of the vapor leakage preventing portion T1 is such that the solvent vapor from the coating liquid 7 is not dispersed when the cylindrical gas 3 is immersed and lowered in the coating container 6 as described above. It can determine suitably within the range which can exhibit.

Thus, for example, the solvent vapor leakage preventing portion T1 extends the outer circumferential wall of the application vessel 6 upward from the position of the application vessel lid 8 or newly adds a member from the position of the application vessel lid 8 above. Can be formed on the coating film outer peripheral wall, or the like. The height may be about 10 to 360 mm, preferably 30 to 100 mm from the surface of the coating liquid 7 in the coating container 6. If the installation height is less than 10 mm, the above effect does not exist, and if the installation height exceeds 360 mm, the effect is effective, but when the cylindrical body 3 is pulled up, the time in the solvent vapor layer becomes long, so that a thick film is applied (20 μm). The above problems are not suitable, and the leveling is too high, and it is not suitable for uniformly forming a thick film, resulting in problems such as complicated apparatus.

In the case of forming the solvent vapor leakage preventing portion T1 with the latter new member, the material of the member may be a solvent resistant material such as aluminum or stainless steel, a metal having corrosion resistance, nylon, Teflon (R), polycarbonate, Plastics with solvent resistance, such as polyethylene and polypropylene, glass, etc. can be used.

It is preferable to provide the solvent vapor generation suppression plate 14 which covers the hole of the coating container 6 without interrupting the immersion and rise of the cylindrical base 3 in the application container 6. By providing this solvent vapor generation suppression plate 14, leakage of the coating solvent vapor to the outside during immersion coating is remarkably prevented.

As a material of the solvent vapor generation suppression plate 14, the plastics, glass, etc. which were mentioned by the said solvent vapor leakage prevention part T1 are preferable.

FIG. 2 shows a state in which the stretchable hood 1 is most retracted by immersing the base 3, where the lowermost part 12 of the stretchable hood 1 is necessarily above the photosensitive body starter 10. It is a structure that is located.

The elastic hood 1 is applied in a wet state by the irregular air flow generated by the airflow entering the application vessel 6 when the cylindrical body 3 is pulled from the lowest end in the application vessel 6 to the top of the application vessel 6. It can suppress the nonuniformity which arises by impacting a film | membrane, or a coating nonuniformity generate | occur | produces to an up-down direction to the maximum.

The elastic hood 1 is in contact with the immersion operation and does not contact the solvent vapor of the coating liquid 7 but does not contact the coating liquid 7 or the coating film.

Formation of the immersion coating layer is performed by immersing and stopping the cylindrical body 3 to the lowest end of the coating liquid, and then stopping by pulling up to 5 to 50 mm, preferably 15 to 35 mm, and lowering it to the bottom end again to stop the solvent vapor leakage. It is pulled out of the upper part of the application container 6 through the inside of the prevention part T1.

In order to prevent the coating film nonuniformity by the convection of the coating liquid 7 in the coating container 6, the stop time in the lowest state should just be 3-30 second, Preferably it is 5-20 second. If it is 3 seconds or less, a coating film nonuniformity will not be eliminated and an effect will not change even if it carries out for 30 seconds or more, and it is unreasonable to reduce production cost.

Moreover, the stop time (natural drying) after pulling up is the purpose of preventing the coating liquid drooping when pulling up a coating film out of a liquid, and providing an equal coating film from the application start, and it is 3 to 30 second, Preferably it is 5 to 20 seconds. In 3 seconds or less, the effect is small and the coating liquid is too dripping to achieve the purpose. In 30 seconds or more, the solvent is too much vaporized in the coating film, so that the coating liquid is difficult to become difficult, resulting in poor leveling. Film thickness step is caused.

Next, the spray coating of this invention is demonstrated.

Fig. 3 schematically shows the spray coating apparatus of the present invention, and the photosensitive member 15 (coated material) on which the surface layer (n-1 layer) coating formed by the immersion coating method of Figs. After mounting, the figure which spray-coated an nth layer is shown typically.

The immersion applied photosensitive member 15 mounted and supported on the jig is rotated at a constant speed by the rotary motor 16, sprays the nth layer coating liquid with the spray coating gun 17, and the total operating range for the coating ( 18) or spraying the entire length of the photosensitive member 15 which is attached and immersed and applied to form a coating film.

The concentration of the spray liquid (n-th layer coating liquid) can be used within 1.0% by weight to 10.0% by weight, and 3.0% by weight to 6.0% by weight is suitable. If it is 1.0 wt% or less, it is necessary to spray more than the high concentration liquid in order to adhere the desired film thickness, so that the film thickness in the wet state (film thickness before the solvent volatilizes) becomes thick, resulting in slow volatilization of the solvent or leveling. It becomes large, and causes a flow nonuniformity. On the other hand, at 10.0% by weight or more, the high concentration liquid is sprayed, resulting in uneven adhesion to the object to be coated 15, resulting in an uneven state of the coating film. It is bad, a lot of irregularities occur. In addition, the liquid viscosity is preferably 3.0 cps to 10.0 cps, preferably 3.0 cps to 5.0 cps, and at 3.0 cps or less, coating unevenness occurs due to liquid dripping, and when it is 10.0 cps or more, the coating film becomes uneven. In many cases, the problem of the uneven state may occur.

The distance 19 between the object to be coated and the spray gun is preferably in the range of 50 mm to 150 mm, preferably 60 mm to 80 mm, and at 50 mm or less, the atomization concentration of the coating becomes high and the spray coating surface becomes uneven. In 150 mm or more, the density | concentration of the coating liquid of the atomization state becomes low, and adhesion efficiency becomes low, or it is easy to cause the coating film defect, such as adhesion of surrounding dust, mist, etc ..

Since the sprayed coating film is formed in the uneven state at the time of spraying at once, it is preferable to set the spraying frequency within 3 times or more in consideration of productivity and the like. It is difficult to repair an uneven | corrugated coating film in 1 time by performing it twice or three times, but since it sprays twice or 3 times in a wet state, the film thickness of a wet state is appropriate and leveled, and an uneven | corrugated state can be suppressed. As for atomizing air pressure which sprays a coating liquid, 1 kgf / cm <2> -3kgf / cm <2> is suitable, and 1.5 kgf / cm <2> -2.0 kgf / cm <2> is preferable. If this is out of this range, a problem arises in which all become concave coated film states.

The rotation speed of the object to be coated 15 is preferably 100 rpm to 300 rpm, preferably 180 to 230 rpm, and if it is 100 rpm or less, many uneven coating films are generated, and if it is 300 rpm or more, the solvent of the applied coating film is rapidly volatilized and leveled. Volatilization (natural drying) at is completed, resulting in a film thickness defect.

10 mm / sec-30 mm / sec are suitable for the moving speed of the spray gun 17, Preferably it is 15 mm / sec-20 mm / sec, and flow nonuniformity arises in 10 mm / sec or less, and 30 mm In / sec or more, it becomes easy to become a convex film thickness.

As for the time to naturally dry the wet coating film formed by spraying on the to-be-coated object 15, 30 sec-180 sec is suitable, Preferably it is 60 sec-120 sec. This natural drying time is largely related to the solid form and adhesion amount of the coating solution formulation, the lower the boiling point, the higher the solvent ratio, the higher the solid content, the smaller the adhesion amount, and the faster the volatilization of solvent, the faster the natural drying time. Faster.

For the formation of the n-th layer provided on the n-th layer, the one containing at least one kind of the n-1-th layer coating liquid solvent is used to contact the interface between the n-1 layer and the layer of the n-th layer. Although it is preferable from the reason that it can improve and maintain the electrostatic characteristic of a photosensitive member, and durability can be improved, at that time, melt | dissolution is prevented by employ | adopting the spray coating method as a coating film formation means of an nth layer as a melt avoidance method of an n-1th layer. Thus, the protective layer structure can be formed without adversely affecting the surface of the electrostatic transport layer.

It is preferable that a nth layer differs from a nth-1 layer in a material structure, and the objective of formation is a function of preventing coating film consumption by repeated image output.

As described above, in the present invention, in forming the photosensitive member material layer on the cylindrical substrate 3, the coating liquid viscosity in the immersion coating method and the spray coating method is specified, and the coating is provided with the solvent vapor leakage preventing unit T1. The problem can be achieved by combining immersion application and spray application by means of an immersion application device having a specific structure including a retractable hood 1 arranged to surround the container 6 and the cylindrical base 3 side circumferential surface. .

Next, the electrophotographic photosensitive member (herein, gas / bottom layer (n-3 layer) / charge generating layer (n-2 layer) / charge transport layer (n-1 layer) / surface protective layer (nth layer) manufactured in the present invention) The material which comprises the photosensitive member which is a laminated constitution of a layer) is demonstrated.

As the cylindrical body 3, a metal cylindrical shape such as aluminum, copper, iron, zinc, nickel, aluminum, copper, gold, silver, platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium, etc. Evaporate metal, deposit conductive metal oxides such as indium oxide and tin oxide, or apply metal foil, or disperse carbon black, indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide, etc. in the binder resin. A well-known material can be used in order to make it the cylindrical-shaped base material electrically conductive by apply | coating.

Moreover, the surface of the said cylindrical body 3 can further perform various processes, such as oxidation treatment of a surface, chemical | medical agent treatment, and coloring process in the range which does not affect image quality as needed.

Bottom layer:

A bottom layer is further provided between the cylindrical base 3 and the charge generating layer, which prevents charge from being injected into the photosensitive layer having a laminated structure from the cylindrical base 3 at the time of charging, and at the same time, It functions as an adhesive layer which can be integrally bonded and held with respect to (3), or prevents reflected light from the cylindrical base 3.

Resin used for this bottom layer is polyethylene, polypropylene, acrylic resin, methacryl resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate, polyurethane, poly Known resins such as mid resin, vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, water soluble polyester, nitrocellulose or casein, gelatin, etc. may be used. It doesn't happen.

Moreover, the thickness of a bottom layer is 0.5-10 micrometers, Preferably 1-7 micrometers is suitable.

As a coating method used when forming a bottom layer, conventional methods, such as the blade coating method, the wire bar coating method, the spray coating method, the dip coating method, the bead coating method, the air knife coating method, the curtain coating method, are mentioned.

Charge generating layer: the layer just below the outermost surface in the immersion coating of the present invention.

The charge generating layer may be, for example, azo dyes such as monoazo dyes, diazo dyes, trisazo dyes, perylene dyes such as perylene acid anhydride and perylene acid imide, Indigo-based pigments such as indigo and thioindigo, polycyclic quinones such as anthraquinone, pyrenequinone and flavantrons, quinacridone pigments, Bisbenzoimidazole-based pigments, indanthrone-based pigments, phthalocyanine-based pigments such as metal phthalocyanine, metal-free phthalocyanine, pyrylium salt pigments, thiarpyrylium salt pigments, Various known charge generating materials (carrier generating materials), such as process compounds formed of polycarbonate, are dissolved in a solvent together with a suitable binder resin and a charge transporting material (carrier transporting materials) as necessary. It can form by dissolving or disperse | distributing and apply | coating.

As the binder resin, butyral resin is suitable as the main component (50 wt% or more), but polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl formal, Polyvinyl ketone, polystyrene, polyvinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, Polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, etc. may be used together as needed.

The amount of the binder resin is 10 to 500 parts by weight, preferably 25 to 300 parts by weight based on 100 parts by weight of the charge generating substance.

As the method for dispersing the charge generating material in the resin, a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used.

At this time, it is effective that the charge generating material has a particle size of 5 µm or less, preferably 2 µm or less, and optimally 0.5 µm or less by volume average particle diameter.

Solvents used for these dispersions are methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, Methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, deoxane, tetrahydrofuran, methylenechlorite, chloroform 1, 2-dichloroethane Or organic solvents such as monochlorobenzene and xylene may be used alone or in combination of two or more thereof.

The film thickness of the charge generating layer used in the present invention is 0.1 to 5 탆, preferably 0.2 to 2 탆.

Charge transport layer: outermost surface layer in immersion coating of the present invention

The charge transport layer can be formed by dissolving or separating the charge transport material and the binder resin in a suitable solvent, and applying and drying this.

As the charge transport material constituting the charge transport layer, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1, 3, 4-oxadiazole, 1, 3, 5-triphenyl-pyrazoline Pyrazoline derivatives such as 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, triphenylamine, styryltriphenyl Aromatics such as amines and dibenzylaniline, tertiary amino compounds, N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1, 1-biphenyl-4 and 4'-diamine 1, 2, 4-, such as an aromatic tertiary diamino compound, 3- (4'-dimethylaminophenyl) -5, 6-di- (4'-methoxyphenyl) -1, 2, 4-triazine, etc. Hydrazone derivatives such as triazine derivatives, 4-diethylaminobenzaldehyde-1, 1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazolin, 6-hydroxy-2, 3 Α-steel, such as benzofuran derivatives such as di (p-methoxyphenyl) -benzofuran, p- (2,2-diphenylvinyl) -N, and N-diphenylaniline Derivatives, enamine derivatives described in Journal of Imaging Science 29: 7-10 (1985), carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and its derivatives, poly-N-carbazolyl Ethyl glutanite and derivatives thereof, and also known pyrene, polyvinyl pyrene, polyvinyl anthracene, polyvinyl acridine, poly-9-biphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin, and the like Charge transport materials can be used.

Moreover, these charge transport materials can be used individually or in mixture of 2 or more types.

Further, as the binder resin in the charge transport layer, polycarbonate resin, polyester resin, methacryl resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, butylene-butadiene copolymer , Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin Known resins such as -N vinylcarbazole can be used.

Moreover, these binder resin can be used individually or in mixture of 2 or more types.

As for the compounding ratio (weight ratio) of a charge transport material and binder resin, 10: 1-1: 5 are preferable. As for the film thickness of a charge transport layer, 10-30 micrometers is preferable.

Moreover, as a solvent used when providing a charge transport layer, they are polar organic solvents, such as a hydroxyl group, an ether group, a ketone group, an ester group, and an acid group, specifically, from methanol, ethanol, tetrahydrofuran, dichloroethane, dichloromethane, etc. Choose one type.

Protective layer: Spray coating layer in this invention

The protective layer is provided for the purpose of preventing the quality of the charge transport layer from being deteriorated by the consumption of the coating film due to the repeated image output and maintaining the initial quality at the endurance quality.

However, the carrier transporting function must also be provided, and the charge transporting material and the binder resin of the material can use a charge transporting layer material, and in order to prevent the charge transporting layer film consumption, an inorganic pigment is added here to consume the protective layer itself. Is suppressed.

As an inorganic pigment, oxides, such as Zn, Ti, Si, Al, Pb, can be used. As for the compounding ratio (weight ratio) of a charge transport material and binder resin, 5: 10-10: 10 are preferable. The inorganic pigment is preferably 5 to 30% of the total weight of the charge transport material and the binder resin.

2.5 micrometers or less are suitable for the film thickness difference of a coating film, and 1.0 micrometers is especially preferable.

Further, as described above, the film thickness of the coating film composed of lamination is charge generation layer <bottom layer? Protective layer <charge transport layer, and / or the lamination total film thickness with respect to the thickness of the cylindrical gas is 1: 1/15 to 1: It is advantageous to control the quality by controlling the production cost and limiting the range of the final outer diameter by configuring 1/35. In addition, as described above, the film thickness of the four-layer laminated layer up to the protective layer can be obtained without any image defects from the beginning, including the difference in the film thickness in the longitudinal direction within 1 µm.

An Example is given to the following and this invention is concretely demonstrated to it.

As described below, the base layer and the charge generating layer were immersed and dried on an aluminum substrate having a diameter of 100 and a thickness of 0.75 mm to sequentially form a photoconductor basic structure.

(Basic composition)

1. Composition of bottom layer coating liquid

Soluble nylon (Alamine CM-8000, Toray Corporation) 5 parts by weight

Methanol95 parts by weight

After applying the bottom layer coating liquid which consists of immersion application | coating to the immersion application apparatus shown in FIG. 1 at 51 mm / s of pulling down speed, 10 sec of immersion lowest stop time, and 10 mm / s of pulling speed, it dries 130 degreeC / 30min, and is made into a film thickness 5.0. A bottom layer of μm was formed.

2. Composition of the charge generating layer coating liquid (liquid viscosity 6 cps)

10 parts by weight of the charge generating layer of the formula

Polyvinyl butyral 7 parts by weight

Tetrahydrofuran 345 parts by weight

In a ball mill and milled for 72 hours. The charge generating coating liquid was immersed and applied at a pulling down speed of 51 mm / s, the immersion lowest stop time 10 sec, and the pulling speed of 7 mm / s to the dip coating device shown in Fig. 1, and then dried at 130 ° C./30 min to obtain a film thickness of 1.0. A charge generating layer of 탆 was formed.

In addition, the coating liquid before immersion coating was measured using the R viscometer system (R115L) by the synchronous industry (company name), and this coating liquid was extract | collected about 10 ml in a sample bottle, and the measurement conditions are rotation speed 100rpm and a setting time. After setting the device condition to 1 min for silver, the constant temperature vessel temperature of 22 ± 2 ℃, and the cone type to 134 '× R24, take 1.0 ~ 1.2ml from the sample bottle immediately with a glass syringe, put it into the measuring cup, and press the measurement start button. . The number of measurements is performed twice, and the data processing after the measurement reads the value of 1min output to the printer, and sets the average value of the two times as the measured value.

Example 1

The charge transport layer was formed by the immersion coating method, and the protective layer was formed by the spray coating method for the photoconductor basic structure.

3. Composition of charge transport layer coating liquid (viscosity 200cps)

8 parts by weight of a charge transport agent of the formula

10 parts by weight of polycarbonate (Panlight C-1400, Teijin Kasei (company name) product)

82 parts by weight of tetrahydrofuran (boiling point 65-66 ° C.)

After dissolving the charge transport layer coating liquid consisting of the coating liquid at a pulling speed of 51 mm / s, the immersion lowest stop time 0 sec and the pulling speed of 8 mm / s, the film was dipped and dried at 110 ° C / 30 min. A charge transport layer having a film thickness of 25 μm was formed.

In addition, the coating liquid before immersion coating was measured using the E-type viscometer system (ELD) made by the synchronous industry (company name), and this coating liquid was extract | collected about 40 ml, The measurement conditions are 50 rpm of rotation speed, and the setting time is 2min. After setting the apparatus conditions to constant temperature vessel temperature 22 +/- 2 degreeC and cone type E, 12-13 ml of sample bottles are immediately taken with a glass syringe, put into a measuring cup, and press a measurement start button. The number of measurements is performed twice, and the data processing after the measurement reads the value of 2min output to the printer, and sets the average value of the two times as the measured value.

4. Composition of protective layer coating liquid (liquid viscosity 3.0 cps)

7 parts by weight of a charge transport agent of the formula

10 parts by weight of polycarbonate (Panlight C-1400, Teijin Kasei (company name) product)

Aluminum oxide 3 parts by weight

300 parts by weight of tetrahydrofuran (boiling point 65-66 ° C.)

Viscosity 3.0cps

The protective layer coating liquid which consists of the apparatus shown in FIG. 3 with a to-be-coated object and a total spray distance of 70 mm, 3 times of spraying times, atomization air pressure 1.5 kgf / cm <2>, rotation speed of a to-be-coated object 200rpm, spraying total moving speed 20mm / The coating was applied under the conditions of sec and a natural drying time of 60 sec, followed by drying at 140 ° C./30 min to form a protective layer having a film thickness of 7 μm. In addition, SP95-25 made from Kubo Engineering Co., Ltd. was used for the spray gun (painting ultra-precision jet device).

In addition, the coating liquid before spray application | coating is measured using R type viscometer system (R115L) by the synchronous industry (company name), and this coating liquid is extract | collected about 10 ml, The measurement conditions are rotation speed 100rpm and measurement time is 1min. After setting the apparatus conditions to 134'xR24, the constant temperature container set temperature of 22 +/- 2 degreeC, extract 1.0-1.2 ml from a sample container with a glass syringe, and press a measurement start button. The number of measurements is performed twice, and the data processing after the measurement reads the value of 1min output to the printer, and sets the average value of the two times as the measured value.

The unevenness of the membrane was performed by the method described above, and the results are shown in Table 1.

Moreover, in addition to evaluation of film thickness or application | coating nonuniformity for every layer, after producing an electrophotographic photosensitive member, the whole solid pattern was output by the Imaggio copier (brand name: imagio) copier, and image nonuniformity was evaluated.

As for the image nonuniformity, the evaluation was performed as the value became higher as 3 as a standard in the 5-step evaluation.

Example 2

In the composition of the protective layer coating liquid, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that 380 parts by weight of tetrahydrofuran and 20 parts by weight of cyclohexanone (boiling point of 156 ° C) were used as the solvent, and the liquid viscosity was changed to 2.8 cps. Produced.

Example 3

In the composition of the protective layer coating liquid, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 300 parts by weight of tetrahydrofuran and 80 parts by weight of cyclohexanone were used as the solvent, and the liquid viscosity was changed to 4.0 cps.

(Comparative Example 1)

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the tetrahydrofuran was increased from 82 parts by weight to 400 parts by weight in the composition of the charge transport layer coating liquid.

(Comparative Example 2)

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the solvent was converted into 80 parts by weight of tetrahydrofuran and 20 parts by weight of cyclohexanone in the composition of the protective layer coating liquid, and the liquid viscosity at that time was 250 cps.

After application of protective layer: Visual ranking Charge transport layer (most surface layer in immersion method) (length-thickness difference: 탆) Charge transport layer (most surface layer in immersion method) (peripheral film thickness difference: 탆) Charge Transport Layer (Surface Layer in Immersion) Application Unevenness: Visual Ranking Uneven film thickness difference in the protective layer (spray coating): μm Image evaluation Example 1 4 0.7 to 1.3 0.8 to 1.5 3 0.9 to 1.1 3 to 4 Example 2 4 to 4.5 0.6 to 1.1 0.7 to 1.0 4 0.7 to 1.0 4 Example 3 5 0.4 to 0.8 0.5 to 0.7 5 0.6 to 0.9 5 Comparative Example 1 3 The film thickness of the target is not attached The film thickness of the target is not attached Non-thickness of target: Less than: 4 to 7 One Comparative Example 2 4 0.3 to 0.8 0.8 to 1.5 4 7 or more caused irregularities due to normal spray 1 to 2

Visual: Rank 5 (Good) → 1 (Poor)

ADVANTAGE OF THE INVENTION According to this invention, the electrophotographic photosensitive member which improved the coating film uniformity of an electric charge transport layer, and controlled the unevenness | corrugation of an outermost surface layer and uniformity, without easily causing a coating liquid dripping, can be provided. have.

Claims (12)

In an electrophotographic photosensitive member formed by laminating an n-layer photosensitive material layer on the surface of a cylindrical substrate, the viscosity of the coating liquid of the n-1 layer is applied to the coating liquid of the n-2 layer and the nth layer. Under immersion application apparatus using an immersion coating apparatus having an immersion coating container having a solvent vapor leakage preventing portion at least on the outer circumferential wall and an elastic hood surrounding the side of the cylindrical gas, under conditions that are greater than any viscosity of the liquid. And the n-th layer and the n-th layer, respectively, and the n-th layer is formed by spray coating. The viscosity of the coating liquid of the said nth-2 layer is 6.0 cps or less, the viscosity of the coating liquid of the said n-1st layer is 150-450 cps, and the viscosity of the coating liquid of a said nth layer is 3.0- An electrophotographic photosensitive member, characterized in that 10.0 cps. The solvent of claim 1, wherein the solvent of the coating liquid of the nth layer is a solvent having at least one of the solvents used in the coating liquid of the nth-1 layer and a boiling point higher than the highest boiling point of the solvent. The electrophotographic photosensitive member which is comprised. The electrophotographic photosensitive member according to claim 3, wherein the difference in boiling point is 65 to 91 占 폚. The electrophotographic photosensitive member according to claim 3, wherein the same solvent used in the coating liquid of the n-th layer in the coating liquid of the n-th layer accounts for 60 to 90% by weight of the whole solvent. The electrophotographic according to any one of claims 1 to 5, wherein the n-th layer is a charge generating layer, the n-th layer is a charge transport layer, and the n-th layer is a surface protective layer. Photosensitive member. In a method of manufacturing an electrophotographic photosensitive member by laminating an n-layer photosensitive member material layer on a surface of a cylindrical substrate, the viscosity of the coating liquid of the n-1th layer is determined by the coating liquid of the n-2 layer and the coating liquid of the nth layer. N-2 under immersion application using an immersion coating apparatus having an immersion coating container having a solvent vapor leakage preventing portion at least on the outer circumferential wall and an elastic hood surrounding the side of the cylindrical gas, under conditions larger than any viscosity. A layer and an nth-1th layer are formed and the said nth layer is formed by spray coating, The manufacturing method of the electrophotographic photosensitive member characterized by the above-mentioned. The viscosity of the n-th layer coating liquid is 6.0 cps or less, the viscosity of the n-th layer coating liquid is 150-450 cps, and the viscosity of the n-th layer coating liquid is 3.0-10.0 cps. The manufacturing method of the electrophotographic photosensitive member characterized by the above-mentioned. 8. The solvent according to claim 7, wherein the solvent of the n-th layer coating liquid is composed of at least one of the solvents used in the n-th layer coating liquid, and a solvent having a boiling point higher than the highest boiling point of the solvent. There is a manufacturing method of the electrophotographic photosensitive member. The manufacturing method of the electrophotographic photosensitive member of Claim 9 whose difference of boiling point is 65-91 degreeC. 10. The production of an electrophotographic photosensitive member according to claim 9, wherein the same solvent used in the coating liquid of the n-th layer in the coating liquid of the n-th layer accounts for 60 to 90% by weight of the whole solvent. Way. The electrophotographic according to any one of claims 7 to 11, wherein the n-th layer is a charge generating layer, the n-th layer is a charge transport layer, and the n-th layer is a surface protective layer. Method of manufacturing the photosensitive member.