JP4264947B2 - Spray coating apparatus for electrophotographic photosensitive member and method for producing electrophotographic photosensitive member - Google Patents

Description

  The present invention relates to a spray coating apparatus for an electrophotographic photosensitive member and a method for producing an electrophotographic photosensitive member using the same, and more particularly, even if a liquid residue of a coating liquid adheres to the tip of a spray gun. The present invention relates to a spray coating type electrophotographic photosensitive member manufacturing apparatus and a manufacturing method capable of stably manufacturing a photosensitive layer comprising a uniform coating film on a workpiece.

An electrophotographic photoreceptor is generally produced by forming a coating film made of a photoreceptor material on the peripheral surface of a photoreceptor substrate.
As a coating method for forming this coating film, compared to the dipping (immersion) method, the amount of coating liquid used is small, and it is effective for coating liquids with a short service life, and there are few restrictions on the shape. The spray coating method is used because of its advantage that it can be applied to a large and long coated body, and the apparatus is small, and it is often used for coating a long and large drum photosensitive member.
However, the spray coating method is a method in which the coating liquid is sprayed as a large number of fine particles from the nozzles of the fine holes of the spray gun and sprayed onto the substrate (substrate surface) to form a film. Moreover, there is a problem that liquid residue adheres to the tip of the gun.
When the liquid residue adheres, the particle size distribution of the fine particles and the spray pattern change, and coating unevenness occurs. For this reason, every time one coated object is applied, the liquid residue adhering to the tip of the gun may have to be cleaned, which reduces productivity.
On the other hand, with high image quality in recent years, electrophotographic photoreceptors used for copying machines, printers and the like are required to have very high uniformity. In particular, in a full-color digital printer, coating film unevenness is likely to occur as an image abnormality. Therefore, in the manufacturing process, a uniform coating film is produced at the expense of productivity.
For this reason, there is a demand for a spray gun that does not require frequent gun tip cleaning because the change in the particle size distribution and spray pattern of the spray mist is small even when liquid residue adheres to the gun tip.

Conventionally, as a method for obtaining a uniform coating film on an electrophotographic photosensitive member, the coating environment at the time of coating film formation is adjusted (temperature environment is 21 ± 3 ° C., humidity environment is 0.012 (kgH ₂ O / kg dry air) or less. ) Method (for example, see Patent Document 1), controlling the coating conditions during spray coating (the wind speed in the vicinity of the conductive support is 0.1 to 1.0 m / sec, and the pressure inside the spray coating booth is less than the outside pressure). .0～0.3MmH ₂ O and a low state) method (for example, see Patent Document 2.), an electrophotographic photosensitive member is formed by spray coating the outermost surface layer, the viscosity of the layer coating liquid immediately below the A method of laminating a photosensitive material layer with a viscosity larger than that of the outermost surface layer coating solution (see, for example, Patent Document 3), a coating solution containing a solvent having a boiling point of 120 ° C. or more and 160 ° C. or less, Adjust application environment (temperature 0 ℃ less, RH 40% humidity) how to spray applied to (e.g., see Patent Document 4.), A method in which the photosensitive layer is spray applied by low-pressure air spray or less air pressure 1.5 kgf / cm ² to be applied (For example, refer to Patent Document 5.) A method of applying an electrophotographic photosensitive layer from a fixed spray nozzle while rotating a cylindrical conductive substrate while moving it in the axial direction (for example, refer to Patent Document 6). Etc. have been proposed.
However, in any of the proposed methods, the spray mist particle size distribution changes when foreign matter (liquid residue or the like) adheres to the nozzle tip of the spray gun. For this reason, when the coating operation is continued without cleaning the gun tip, unevenness of the coating film occurs and a uniform coating film cannot be formed.

Further, as a method with good coating efficiency for obtaining a uniform coating film, the spray cone in the main scanning direction of the photoconductor substrate is made larger than the spread of the spray cone in the sub-scanning direction of the photoconductor substrate, and the shape of the spray pattern There has been proposed a method of spraying a photoreceptor coating on the surface of a photoreceptor substrate so that the major axis / minor axis ratio is 2/1 (see, for example, Patent Document 7).
Alternatively, as a method of obtaining a uniform coating film, an angle formed by a projection vector onto a plane including the center of the spray nozzle outlet and the center axis of the photosensitive member base and a movement direction vector of the spray nozzle is set to 0 °. There has been proposed a method of spray application (see, for example, Patent Document 8) while setting the angle to be greater than 90 ° and moving the spray nozzle parallel to the central axis.
However, in any of the above proposed methods, if a foreign matter such as liquid residue adheres to the tip of the spray gun nozzle, the spray pattern changes, and coating unevenness occurs, making it impossible to form a uniform coating.

Further, as a step of laminating the surface protective layer on the photosensitive layer of the electrophotographic photosensitive member in which the photosensitive layer and the surface protective layer are continuous, the volume volume V (cm ³ / s) of the surface protective layer per second is 1.0 ×. A method of obtaining a coating film under spray conditions of 10 ⁻³ <V <1.0 × 10 ⁻² has been proposed (see, for example, Patent Document 9).
However, in the above method, when a foreign substance adheres to the tip of the nozzle, the spray pattern changes, the liquid adhesion amount per unit time becomes uneven, and coating film unevenness is likely to occur.

On the other hand, as a method to remove the nozzle tip contamination of the spray gun, a method is proposed in which a cap is applied to the tip of the spray gun after the coating film is formed, and cleaning liquid is introduced from the nozzle through the air ejection hole to clean the inner and outer surfaces of the nozzle tip. (For example, refer to Patent Document 10).
However, this method requires a cleaning jig, and further requires a cleaning time, which reduces productivity and increases manufacturing costs.

Alternatively, a method of making the diameter of the atomizing air nozzle 4 to 10 times the inner diameter of the paint nozzle has been proposed in order to prevent skinning and alteration of the aqueous emulsion adhering to the tip portion of the spray gun (for example, Patent Document 11). reference.).
In addition, a method has been proposed in which the paint is prevented from adhering to the tip of the paint injection port so that the paint solidified into particles does not fly (see, for example, Patent Document 12).
However, none of the above methods is sufficiently effective as a method for preventing the paint from adhering to the tip portion of the spray gun or the paint injection port, and the adhesion of the paint cannot be completely eliminated. For this reason, in the case of continuous production, there arises a problem that the uniformity of the formed coating film is inferior due to the influence of the adhered paint.

In addition, a method has been proposed in which a solvent is mixed in the atomizing air so that the tip of the nozzle is always washed with a solvent, and a uniform coating film is obtained so that the paint does not adhere to the tip of the nozzle and solidify (for example, patents). Reference 13).
However, this method has a problem that the atomization of the coating liquid becomes insufficient, and the uniformity of the formed coating film is not sufficient and inferior.

Japanese Patent Laid-Open No. 5-27455 JP 2003-156862 A JP 2003-149836 A JP 2000-75511 A Japanese Patent Laid-Open No. 11-253872 JP 2003-122035 A Japanese Patent Publication No. 5-45026 JP 2000-221707 A JP 2003-98695 A JP 2003-2111064 A JP-A-8-238450 Japanese Patent Laid-Open No. 11-114458 Japanese Patent Laid-Open No. 11-128788

  The present invention has been made in view of the above-described prior art, and does not require frequent cleaning even when liquid residue adheres to the tip of the spray gun when an electrophotographic photosensitive member is manufactured using a spray coating method. Without changing the particle size distribution or spray pattern of the fine particles of the coating liquid (hereinafter, sometimes referred to as spray mist or mist) continuously sprayed without reducing productivity, Hereinafter, it may be expressed as a workpiece.) An object of the present invention is to provide a manufacturing apparatus and a manufacturing method capable of stably forming a uniform coating film thereon. In particular, the present invention aims to provide a manufacturing apparatus and a manufacturing method that are suitably used for manufacturing an electrophotographic photosensitive member of a full-color digital printer.

  As a result of intensive studies, the present inventors have rigorously adjusted the mutual positional relationship and dimensions of the frustoconical nozzle and the hollow frustoconical air cap that constitute the spray gun that sprays the coating liquid in a mist form. Thus, even when a liquid residue of the coating liquid adheres to the tip of the spray gun, it has been found that a uniform coating can be stably formed without occurrence of unevenness without requiring frequent cleaning. .

That is, the present invention provides a coating liquid supply means, an atomizing air supply means, a truncated cone-shaped nozzle configured to feed the coating liquid and the atomized air, and the truncated cone-shaped nozzle. A spray gun having a hollow frustoconical air cap surrounding the substrate, and a coating liquid is sprayed from the spray gun to be selected from an undercoat layer, a charge generation layer, and a charge transport layer on the substrate. In a spray coating apparatus for an electrophotographic photoreceptor in which at least one layer is applied and formed,
Wherein the nozzle discharge opening is provided with a flow path for feeding a coating liquid, air gap and an outlet for feeding the atomizing air between said nozzle and said air cap is provided,
Inside the air cap facing said Nozzle constitutes said space straight cylindrical extending from the outlet of the atomizing air and the straight cylindrical truncated cone shaped space portion extending from the space Shape,
The spray coating apparatus for an electrophotographic photosensitive member, wherein a height of the right circular cylinder in the right circular cylindrical space is 0.1 mm or more and 0.3 mm or less .

  Here, in the spray coating apparatus for the electrophotographic photosensitive member of the present invention, the arrangement is such that the most advanced position of the air cap tip opening is the same or the front of the most advanced position of the nozzle tip. It is preferable that

Further, in the spray coating apparatus for an electrophotographic photosensitive member of the present invention, an opening angle of an inner inclined cylindrical surface forming the frustoconical space portion in the air cap having a hollow frustoconical shape facing the nozzle is formed. It is preferably 80 ° or more and 120 ° or less.

  In the spray coating apparatus for an electrophotographic photosensitive member of the present invention, the minimum gap size of the gap sandwiched between the air cap inner peripheral wall surface of the air cap tip and the nozzle outer peripheral wall surface of the nozzle tip is 0.2 mm. As mentioned above, it is preferable that it is 1.0 mm or less.

A coating liquid supply means, an atomizing air supply means, a frustoconical nozzle configured to feed the coating liquid and the atomizing air, and a hollow frustoconical shape surrounding the frustoconical nozzle A spray coating apparatus for an electrophotographic photosensitive member having a spray gun having an air cap is used, and a coating liquid is sprayed from the spray gun to form an undercoat layer, a charge generation layer, and a charge on the substrate. A method for producing an electrophotographic photosensitive member by coating and forming at least one layer selected from transport layers ,
Feeding the coating solution from the flow path and a discharge port provided in the nozzle, while discharging, the atomizing air feeding, and discharged from the gap between the discharge port provided between said nozzle and said air cap, Spray and apply the coating liquid as fine particles ,
The inner side of the air cap facing the nozzle forms a right columnar space extending from the atomizing air outlet and a frustoconical space extending from the right columnar space. And
In the method for producing an electrophotographic photosensitive member, the height of the right circular cylinder in the right circular cylindrical space is 0.1 mm or more and 0.3 mm or less .

  In the above-described electrophotographic photosensitive member manufacturing method of the present invention, the air cap tip opening portion is arranged and configured so that the leading end position of the air cap tip portion is the same as or the front surface with respect to the leading end position of the nozzle tip portion. preferable.

In the method for producing an electrophotographic photosensitive member of the present invention, an open angle of an inner inclined cylindrical surface forming the frustoconical space in the air cap having a hollow frustoconical shape facing the nozzle is 80 °. As mentioned above, it is preferable that it is 120 degrees or less.

  In the method of manufacturing the electrophotographic photosensitive member of the present invention, the minimum gap dimension of the gap sandwiched between the air cap inner peripheral wall surface of the air cap tip and the nozzle outer peripheral wall surface of the nozzle tip is 0.2 mm or more, 1 It is preferable that it is 0.0 mm or less.

  In the method for producing an electrophotographic photosensitive member according to any one of the present inventions, it is preferable that the pressure of the supplied atomizing air is 0.01 MPa or more and 0.5 MPa or less immediately before being introduced into the spray gun.

In the method for producing an electrophotographic photosensitive member according to any one of the present invention,
The solvent used in the coating solution is a mixed solvent, and the mixed solvent contains a solvent having a vapor pressure of 0.1 to 20 mmHg at least at 20 ° C., and the content is 10 wt% or more and 70 wt% or less. Preferably there is.

  Furthermore, in the method for producing an electrophotographic photosensitive member according to any one of the present invention, the particle size distribution of the coating liquid fine particles sprayed by the atomizing air from the spray gun is 1 μm or more and 30 μm immediately before adhering to the coated body. The following (measurement standard: D90 μm) is preferable.

  Furthermore, in the method for producing an electrophotographic photosensitive member according to any one of the present invention, it is preferable that the viscosity of the coating solution is 0.01 mPa · s or more and 5 mPa · s or less.

According to the manufacturing apparatus equipped with the spray gun according to the present invention, even when the liquid residue of the coating liquid adheres to the tip of the spray gun when the electrophotographic photosensitive member is manufactured, the influence of the liquid residue is reduced. The change in the particle size distribution and spray pattern of spray fine particles (spray mist) becomes small. Thereby, a uniform coating film with no occurrence of unevenness can be stably formed on the substrate (workpiece). In addition, according to the manufacturing method of the present invention, since it is not necessary to frequently clean the liquid residue during the coating operation, the productivity is not sacrificed, and the cost can be reduced in the manufacture of the electrophotographic photosensitive member. it can.
In other words, by using the spray coating apparatus of the present invention and applying the manufacturing method of the present invention, the coating film having extremely high coating film uniformity (non-uniformity that causes image abnormality) required for high image quality is applied. An electrophotographic photoreceptor having a film) can be efficiently produced. As a result, an electrophotographic photosensitive member for a full-color digital printer and a long and large-diameter photosensitive member are provided.
In addition, since it can be applied with a spray gun, it is smaller and simpler than a dipping system, and can be applied to large and long coated objects, so it can be widely applied to the general spray coating field. is there.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic configuration diagram of a spray coating apparatus for an electrophotographic photosensitive member according to the present invention.
As shown in FIG. 1, the spray coating apparatus 1 of the present invention is configured so that the coating liquid supply means 2, the atomizing air supply means 3, and the coating liquid 2A and the atomizing air 3A are fed, respectively. The spray gun 4 is configured.
The spray gun 4 is composed of a nozzle 5 and an air cap 6, and the mutual positional relationship and dimensions are suitable so that a stable spray mist can be sprayed even if a liquid residue of the coating liquid adheres to the tip of the spray gun. It has been adjusted. Then, the application liquid whose viscosity and the vapor pressure of the solvent are adjusted is supplied from the application liquid supply means 2 and the atomization air whose pressure is adjusted (controllable by adjusting the flow rate) is supplied from the atomization air supply means 3. Is supplied, and the coating liquid is sprayed from the spray gun 4 as a spray mist.

The structure of the spray gun 4 is configured by, for example, a design as shown in the schematic sectional view of FIG.
In FIG. 2, the spray gun 4 includes the truncated cone-shaped nozzle 5 and the hollow truncated cone-shaped air cap 6 as described above. The nozzle 5 is provided with a flow path 7 and a discharge port 8 for supplying the coating liquid 2A. A gap 9 and a discharge port 10 for supplying the atomized air 3 </ b> A are provided between the air cap 6 and the nozzle 5.
That is, the coating liquid 2A supplied from the coating liquid supply means 2 (FIG. 1) is discharged from the discharge port 8 via the flow path 7 and supplied from the atomizing air supply means 3 (FIG. 1). The atomized air 3A is discharged from the discharge port 10 via the gap 9 provided between the air cap 6 and the nozzle 5, and thereby the coating liquid is atomized and sprayed.
In addition, as shown in FIG.2 (b), although the needle (5n) is arrange | positioned in the flow path 7 of the nozzle 5 so that position adjustment is possible, it abbreviate | omits in the following detailed description.

In order to stably form a uniform coating film without unevenness on the workpiece even when the liquid residue of the coating liquid adheres to the tip of the spray gun during the coating operation with the spray gun configured as described above. As described above, it is necessary to prevent the particle size distribution of the spray mist sprayed and the spray pattern from changing.
The positional relationship and dimensions of the spray gun nozzle and the air cap in the present invention for solving the above problems will be described below. The name of each part used in the description is shown in FIG.

First, as shown in FIG. 4, a right columnar shape extending from the atomizing air discharge port 10 formed between the air cap tip opening portion 12 facing the nozzle tip portion 11 of the atomizing air discharge port 10. The dimension of the height of the right circular cylinder in the space (hereinafter sometimes referred to as the inner surface width) (b) is 0.1 mm or more and 0.3 mm or less. The height (inner surface width) of the right circular cylinder in the right cylindrical space portion is the axial length (width) of the cylindrical inner surface portion that becomes the boundary with the substantially right cylindrical space portion that continues from the opening of the air cap tip. Point to .
Here, when the inner surface width (b) is smaller than 0.1 mm, the strength and durability are insufficient, and it becomes difficult to use as a spray coating apparatus. On the other hand, when it is larger than 0.3 mm, when liquid residue adheres to the tip of the spray gun, the change in the flow path of the atomizing air affects the particle size distribution and the spray pattern.
A more preferable range of the inner surface width is 0.1 mm or more and 0.25 mm or less, and a particularly preferable range is 0.1 mm or more and 0.2 mm or less.

Next, as shown in FIG. 5, the distance (c) between the air cap most advanced position 14 and the nozzle most advanced position 13 is preferably set to a dimension of 0 mm or more. That is, it is preferable to arrange and configure the air cap leading edge position 14 so as to be the same or the front surface with respect to the nozzle leading edge position 13.
As a method of setting such an arrangement relationship, the nozzle 5 may be fixed and the air cap 6 may be moved, or the air cap 6 may be fixed and the nozzle 5 may be moved.

By setting the distance (c) between the air cap leading edge position 14 and the nozzle leading edge position 13 to 0 mm or more as described above, even when liquid debris adheres to the tip of the spray gun, The change is small, and the particle size distribution and spray pattern of the spray mist do not change so much, and a uniform coating film can be formed.
If the interval is smaller than 0 mm (the air cap leading edge position 14 becomes the rear surface with respect to the nozzle leading edge position 13), the particle size distribution of the spray mist and the spray pattern are affected, and a uniform coating film is formed. It cannot be formed.
A more preferable range of the distance between the air cap leading edge position 14 and the nozzle leading edge position 13 is 0 mm or more and 0.5 mm or less, and a particularly preferable range is 0 mm or more and 0.3 mm or less.

Further, as shown in FIG. 6, the opening angle of the inclined cylindrical surface inside the air cap (the angle between the two oblique sides of the trapezoidal cross section passing through the axis: hereinafter referred to as a taper angle) (d) is 80 ° or more. A range of 120 ° or less is preferable.
When the taper angle is smaller than 80 ° or larger than 120 °, when the liquid residue adheres to the tip of the spray gun, the atomizing air flow path changes and the spray mist particle size distribution and spray pattern Changes greatly, and a uniform coating film cannot be formed.
A more preferable range of the taper angle is 80 ° or more and 110 ° or less, and a particularly preferable range is 90 ° or more and 100 ° or less.

Furthermore, as shown in FIG. 7, the minimum gap dimension (a) between the air cap inner peripheral wall surface of the air cap tip 12 and the nozzle outer peripheral wall surface of the nozzle tip 11 is 0.2 mm or more, 1 It is preferably within a range of 0.0 mm or less. If the minimum gap size is smaller than 0.2 mm or larger than 1.0 mm, when the liquid residue adheres to the tip of the spray gun, the atomizing air flow path changes and the spray mist particles The diameter distribution and spray pattern change greatly, and a uniform coating film cannot be formed.
A more preferable range of the minimum gap dimension (a) of the gap is 0.5 mm or more and 1.0 mm or less, and a particularly preferable range is 0.5 mm or more and 0.8 mm or less.

Next, a method for producing the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 8 is a schematic diagram showing an example of the configuration of a coating system when a coating solution is spray-coated on an object to be coated (work) using the spray coating apparatus for an electrophotographic photosensitive member of the present invention.
In FIG. 8, the work 51 is rotatably arranged in the coating booth 52, while the spray gun 53 is attached to the guide rail 54 so as to be movable along the axial direction of the work 51. The coating booth 52 is provided with a clean air supply port 55 and an exhaust port 56 in order to eliminate excess spray mist sprayed from the spray gun 53. Then, the application liquid is supplied from the application liquid tank 58 of the application liquid supply means 57 by the pump 59, and the atomization air is supplied from the atomization air tank 61 of the atomization air supply means 60 by the pump 62. It is atomized and sprayed onto the work 51 from the spray gun 53.

Here, the positional relationship and dimensions between the nozzle of the spray gun and the air cap used in the method for manufacturing the electrophotographic photosensitive member are based on the inner surface width of the air cap tip opening as described above, and the most advanced position of the air cap. And the tip end position of the nozzle, the taper angle on the inner side of the air cap, and the minimum gap size of the gap sandwiched between the inner peripheral wall surface of the air cap and the outer peripheral wall surface of the nozzle at each tip.
By using the spray gun adjusted in this way, even if a liquid residue of the coating liquid adheres to the tip of the spray gun, a uniform coating film can be continuously obtained without frequently cleaning the tip of the gun, Productivity is not reduced.

Further, when an electrophotographic photosensitive member is manufactured using a spray coating apparatus equipped with any one of the above-described preferred spray guns, the pressure of the atomized air to be supplied is 0. 0 immediately before being introduced into the spray gun. It is preferably 01 MPa or more and 0.5 MPa or less.
When the atomizing air pressure is lower than 0.01 MPa, the coating liquid is not sufficiently atomized, and coating unevenness occurs. On the other hand, if the pressure is greater than 0.5 MPa, the mist strikes the workpiece violently, resulting in uneven coating. Note that the pressure of the atomizing air can be controlled by adjusting the flow rate.
A more preferable range of the pressure is 0.01 MPa or more and 0.3 MPa or less, and a particularly preferable range is 0.01 MPa or more and 0.2 MPa or less.

Similarly, when an electrophotographic photosensitive member is produced using a spray coating apparatus equipped with any one of the above-described preferred spray guns, the solvent used in the coating solution is a mixed solvent, and the mixed solvent includes at least A solvent having a vapor pressure of 0.1 to 20 mmHg at 20 ° C. is preferably contained, and the content thereof is preferably 10% by weight or more and 70% by weight or less.
That is, when the content of the low vapor pressure solvent is less than 10% by weight, the evaporation of the solvent in the mist is too fast, the leveling on the work becomes insufficient, and the coating film unevenness occurs. On the other hand, when the content is more than 70% by weight, not only does it take time to dry the coating film, but the productivity is lowered, and the coating environment is easily affected by the coating environment.
A more preferable range of the content is 10% by weight or more and 60% by weight or less, and a particularly preferable range is 10% by weight or more and 50% by weight or less.
The solvent may have a vapor pressure of 0.1 to 20 mmHg at 20 ° C., but is easy to dissolve various resins used in the coating solution, has good compatibility with other solvents to be mixed, and is formed by coating. It is preferable that the surface state does not deteriorate during the drying process of the coated film (generation of crushed skin, etc.). As such a solvent, for example, it is preferable to use a combination of cyclohexanone as a mixed solvent of methyl ethyl ketone and tetrahydrofuran.

Furthermore, when producing an electrophotographic photosensitive member using a spray coating apparatus equipped with any one of the above-described preferred spray guns, the particle size distribution of the spray mist sprayed by the atomizing air from the spray gun is: It is preferably 1 μm or more and 30 μm or less immediately before adhering to the object to be coated.
Here, the particle size distribution is expressed using D90 μm as a measurement standard, and the meaning of D90 μm represents that particles having a particle size equal to or less than the value of the marked particle size occupy 90% of the total volume.
When the particle size distribution is smaller than 1 μm, the spray mist easily floats on the surrounding air current, and the adhesion efficiency to the object to be coated tends to decrease. Also, it is difficult to manage and control the coating environment, such as cleaning the coating booth, and the cost tends to increase. On the other hand, when the particle size distribution is larger than 30 μm, the impact is great when the mist hits the workpiece, and coating unevenness is likely to occur. If the particle size distribution is 30 μm or less, the mist adheres softly to the workpiece, so that coating film unevenness does not occur. Moreover, since mist accumulates densely, a uniform coating film can be produced.
A more preferable range of the particle size distribution is 1 μm or more and 20 μm or less, and a particularly preferable range is 1 μm or more and 10 μm or less.

In addition, when an electrophotographic photosensitive member is produced using a spray coating apparatus equipped with any one of the above-described spray guns, the viscosity of the coating solution is 0.01 mPa · s or more and 5 mPa · s or less. It is preferable.
That is, if the viscosity of the coating solution is too low or too high, the coating solution cannot be made fine and spray coating cannot be performed. Furthermore, if it is greater than 5 mPa · s, the efficiency of atomization is poor, and liquid debris is likely to be generated at the tip of the gun. If it is 5 mPa · s or less, the formation of fine particles occurs efficiently, so that liquid debris is hardly generated.
A more preferable range of the viscosity of the coating solution is 0.05 mPa · s or more and 4 mPa · s, and a particularly preferable range is 0.1 mPa · s or more and 3 mPa · s.

Next, the electrophotographic photosensitive member manufactured by the manufacturing method using the spray coating apparatus for the electrophotographic photosensitive member of the present invention will be described. The following description does not limit the electrophotographic photosensitive member in the present invention.
As an example of the configuration of the electrophotographic photosensitive member, an undercoat layer, a charge generation layer, a charge transport layer, a protective layer, and the like are sequentially provided on a substrate (base). Each layer will be specifically described below with reference to the configuration of this example.
First, as a substrate for an electrophotographic photoreceptor, a drum or sheet of a metal material such as aluminum, copper, iron, zinc, or nickel; or on paper, plastic, or glass, aluminum, copper, gold, silver, platinum, Materials deposited with metals such as palladium, titanium, nickel-chromium, stainless steel, copper-indium, materials deposited with conductive metal oxides such as indium oxide and tin oxide, materials laminated with metal foil, or carbon black Various drum-like, sheet-like, or plate-like materials, such as materials that are electrically conductive by dispersing and coating indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide, etc. in a binder resin However, the present invention is not limited to these.

The surface of the substrate (conductive support) for the electrophotographic photoreceptor can be subjected to various treatments within a range that does not affect the image quality, if necessary. For example, oxidation treatment, chemical treatment, coloring treatment and the like can be performed on the surface. Further, an undercoat layer can be provided between the conductive support and the charge generation layer.
By providing this undercoat layer, injection of charges from the conductive support to the photosensitive layer is prevented during charging, and the photosensitive layer is integrally bonded and held to the conductive support. Effects such as a function as a layer or a function of preventing reflected light from entering from the conductive support can be obtained.

The resin used for the undercoat layer is polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate resin, polyurethane Examples of such resins include, but are not limited to, resins, polyimide resins, vinylidene chloride resins, polyvinyl acetal resins, vinyl chloride-vinyl acetate copolymers, polyvinyl alcohol resins, water-soluble polyester resins, nitrocellulose or casein, and gelatin. It is not something.
The thickness of the undercoat layer is 0.01 to 10 μm, preferably 0.3 to 7 μm.

  Examples of the charge generation layer (carrier generation layer) include azo dyes such as monoazo dyes, disazo dyes and trisazo dyes, perylene dyes such as perylene acid anhydride and perylene imide, indigo dyes such as indigo and thioindigo, Polycyclic quinones such as anthraquinone, pyrenequinone and flavanthrone, quinagridone dyes, bisbenzimidazole dyes, indanthrone dyes, squarylium dyes, metal phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments, pyrylium salt dyes, Various known charge generating materials (carrier generating materials) such as eutectic complexes formed from thiapyrylium salt dyes and polycarbonate are used. These carrier generating materials can be dissolved or dispersed in a solvent together with an appropriate binder resin to form a coating solution, which can be coated on the undercoat layer to form a charge generating layer. In addition, it can be used as a coating liquid to which a charge transport material (carrier transport material) is further added as necessary.

  Examples of the method for dispersing the charge generation material in the resin include a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method. At the time of dispersion, it is effective that the charge generating material has a volume average particle size of 5 μm or less, preferably 2 μm or less, and most preferably 0.5 μm or less. The thickness of the charge generation layer used in the present invention is generally 0.1 to 5 μm, preferably 0.2 to 2 μm.

Next, the charge transport layer is formed by containing a charge transport material in a suitable binder resin (binder) and coating it.
As a charge transport material, oxazoazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2) ] Pyrazoline derivatives such as 3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, aromatics such as triphenylamine, styryltriphenylamine, dibenzylaniline, tertiary amino compounds, N, Aromatic tertiary diamino compounds such as N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1-biphenyl-4,4'-diamine, 3- (4'-dimethylaminophenyl) 1,2,4-triazine derivatives such as -5,6-di- (4'-methoxyphenyl) -1,2,4-triazine, 4-die Hydrazone derivatives such as luaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinzoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran , P- (2,2-diphenylvinyl) -N, α-stilbene derivatives such as N-diphenylaniline, enamine derivatives described in “Journal of Imaging Science” 29: 7-10 (1985), N-ethyl Carbazole derivatives such as carbazole, poly-N-vinylcarbazole such as poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutanate and derivatives thereof, and pyrene, polyvinylpyrene, polyvinylanthra Emissions, polyvinyl acridine, poly-9-biphenyl-anthracene, pyrene - formaldehyde resins, but may be a known charge transport material such as ethyl carbazole formaldehyde resin, but is not limited thereto. These charge transport materials can be used alone or in combination of two or more.

As binders used in the charge transport layer, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, butylene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer Polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N vinylcarbazole, etc. Known resins can be used, but are not limited to these. These binder resins can be used alone or in combination of two or more.
The blending ratio (weight ratio) between the charge transport material and the binder is preferably 10: 1 to 1: 5. The thickness of the charge transport layer used in the present invention is generally 5 to 50 μm, preferably 10 to 30 μm.

In addition, in the electrophotographic photoreceptor in this example, a charge transport material and a pigment can be contained in a suitable binder as a protective layer on the charge transport layer.
As the pigment, in addition to inorganic pigments such as alumina and titanium oxide, organic pigments may be used. The weight ratio of the pigment in the total solid content is preferably 5 to 30%. The thickness is generally 2 to 10 μm, preferably 4 to 8 μm. The protective layer may not be provided depending on the copying machine or printer used.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.
Example 1
With the composition shown below, coating solutions for the undercoat layer, the charge generation layer, and the charge transport layer were prepared, and were laminated by spray coating under the following coating conditions to prepare an electrophotographic photoreceptor. Each layer was formed by continuous spray application of 10 layers, and 10 layers of the electrophotographic photosensitive member were produced by sequentially laminating each layer.

[Formation of undercoat layer]
<Preparation of coating solution for undercoat layer>
15 parts by weight of alkyd resin (Beccosol 1307-60-EL: manufactured by Dainippon Ink & Chemicals), 10 parts by weight of melamine resin (Super Becamine G-821-60: manufactured by Dainippon Ink & Chemicals) 320 parts by weight of methyl ethyl ketone 90 parts by weight of titanium oxide powder (Typer CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) was added thereto and dispersed for 12 hours by a ball mill.
The obtained solution was taken out into a container and further diluted with 140 parts by weight of cyclohexanone to obtain a coating solution for an undercoat layer.
<Coating conditions for coating solution for undercoat layer>
Applying the coating system configuration of the schematic diagram shown in FIG. 8 to the prepared undercoat layer coating solution, the spray coating apparatus for the electrophotographic photosensitive member of the present invention has a diameter of 170 mm and a length of 410 mm. An undercoat layer was formed by spray coating on a nickel seamless belt (coated body / work).
As the spray gun of the spray coating apparatus used here, one having a configuration as shown in the schematic sectional view of FIG. 9 was used. Descriptions and specifications of each symbol in FIG. 9 are shown below.
Explanation of each code:
(A): Minimum gap size of the gap between the air cap inner diameter and nozzle outer diameter of each tip (b); Inner width of the air cap tip (c); Air cap leading edge position and nozzle leading edge position (D); Taper angle inside the air cap (θ); Taper angle outside the nozzle (e); Distance between the most advanced position of the needle and the most advanced position of the nozzle (t1); Nozzle inner wall and needle in the flow path The gap between the outer wall of the nozzle (t2);
(A); 0.1 mm, (b); 0.2 mm, (c) -0.1 mm, (d); 78 °, (θ); 30 °, (e); 1.4 mm, (t1); 0.01 mm, (t2); 0.2 mm,
Other conditions:
Material of spray gun: Cemented carbide Alloy Atomization air flow rate: 10L / min
Under the above conditions, an undercoat layer coating solution was spray-coated on a nickel seamless belt, and then dried at 140 ° C. for 20 minutes to form an undercoat layer having a thickness of 8.2 μm.

[Formation of charge generation layer]
<Preparation of coating solution for charge generation layer>
Next, 5 parts by weight of polyvinyl butyral resin (S-REC HL-S: manufactured by Sekisui Chemical Co., Ltd.) is dissolved in 150 parts by weight of methyl ethyl ketone, and 10 parts by weight of a trisazo pigment represented by the following structural formula (1) is added to the ball mill. And then dispersed for 48 hours by adding 210 parts by weight of cyclohexanone. The obtained solution was taken out into a container and further diluted with 600 parts by weight of methyl ethyl ketone to obtain a charge generation layer coating solution.

<Coating conditions for coating solution for charge generation layer>
As in the case of the undercoat layer, the coating solution for the charge generation layer prepared above was coated with the coating system configuration of FIG. 8 and the spray coating apparatus for the electrophotographic photosensitive member of the present invention. The charge generation layer was formed by spray coating on the coated body (work).
The spray gun of the spray coating apparatus used here was the same as that of the undercoat layer, but some specifications were changed.
Specifications:
(A); 0.1 mm, (b); 0.2 mm, (c) -0.1 mm, (d); 78 °, (θ); 30 °, (e); 1.0 mm, (t1); 0.01 mm, (t2); 0.2 mm,
Atomizing air flow rate: 25 L / min
The coating solution for charge generation layer was spray-coated on the workpiece under the above conditions, and then naturally dried to form a charge generation layer having a thickness of 0.5 μm.

[Formation of charge transport layer]
<Preparation of coating solution for charge transport layer>
Next, 10 parts of bisphenol A polycarbonate resin and 0.002 part of silicon oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) are dissolved in 160 parts of tetrahydrofuran, and 8 parts of a charge transport material of the following structural formula (2) are dissolved therein. Was added and dissolved, and diluted with 160 parts by weight of cyclohexanone to prepare a coating solution for a charge transport layer.

<Coating conditions for coating solution for charge transport layer>
As in the case of the undercoat layer, the charge transport layer was formed using the coating system configuration shown in FIG. 8 and the spray coating apparatus for the electrophotographic photosensitive member of the present invention.
The spray gun of the spray coating apparatus used here was the same as that of the undercoat layer, but some specifications were changed.
Specifications:
(A); 0.1 mm, (b); 0.2 mm, (c) -0.1 mm, (d); 78 °, (θ); 35 °, (e); 1.5 mm, (t1); 0.02 mm, (t2); 0.2 mm,
Atomization air flow rate: 20 L / min
The coating solution for charge transport layer was spray-coated on the workpiece under the above conditions, and then dried at 160 ° C. for 20 minutes to form a charge transport layer having a thickness of 25 μm.
Ten electrophotographic photoreceptors of Example 1 were produced by continuous coating as described above.

In Table 1, the cyclohexanone content of each coating solution and the viscosity of each coating solution are shown in Table 1 below. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.
In Table 2, the particle size distribution is measured by a laser light scattering type particle size distribution measuring device LDSA-3400A (manufactured by Tohnichi Computer Applications), and σ is the particle size distribution of sprayed fine particles (D90 μm). Represents standard deviation. The maximum film thickness difference was measured with an electronic micrometer (manufactured by Anritsu).

Example 2
In the same manner as in Example 1, coating solutions for the undercoat layer, the charge generation layer, and the charge transport layer were prepared, and the coating conditions (a) in Example 1 were changed from 0.1 mm to 0.5 mm. Example 1 except that (c) was changed from −0.1 mm to 0.2 mm, (d) was changed from 78 ° to 95 °, and the atomizing air flow rate at the time of application of each coating solution was changed as follows. Ten electrophotographic photoreceptors of Example 2 were produced by continuous coating in the same manner as in Example 1.
Atomization air flow conditions:
At the time of application of the coating solution for the undercoat layer: 20 L / min (film thickness of the formed undercoat layer: 8.2 μm)
At the time of application of the charge generation layer coating solution: 40 L / min (film thickness of the formed charge generation layer: 0.5 μm)
At the time of application of the charge transport layer coating solution: 30 L / min (film thickness of the formed charge transport layer: 25 μm)

  The cyclohexanone content of each coating solution and the viscosity of each coating solution in Example 2 are shown in Table 1 below. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 1
Implementation was performed except that the inner surface width (b) of the air cap tip under the coating conditions in Example 1 was changed from 0.2 mm to 0.4 mm, and the atomizing air flow rate at the time of applying each coating liquid was changed as follows. Ten electrophotographic photosensitive members of Comparative Example 1 were produced by continuous coating in the same manner as in Example 1 .
Atomization air flow conditions:
During application of the coating solution for the undercoat layer: 8 L / min (film thickness of the formed undercoat layer: 8.2 μm)
At the time of application of the charge generation layer coating solution: 20 L / min (film thickness of the formed charge generation layer: 0.5 μm)
At the time of application of the charge transport layer coating solution: 15 L / min (film thickness of the formed charge transport layer: 25 μm)

  Table 1 below shows the cyclohexanone content of each coating solution and the viscosity of each coating solution in Comparative Example 1. In addition, Table 2 below shows the pressure of atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 2
In the same manner as in Comparative Example 1 except that (a) of the coating conditions in Example 1 was changed from 0.1 mm to 1.1 mm, and the atomizing air flow rate at the time of application of each coating solution was changed as follows. Ten electrophotographic photoreceptors of Comparative Example 2 were produced by continuous coating.
Atomization air flow conditions:
At the time of application of the coating solution for the undercoat layer: 40 L / min (film thickness of the formed undercoat layer: 8.2 μm)
During application of the charge generation layer coating solution: 60 L / min (film thickness of the formed charge generation layer: 0.5 μm)
At the time of application of the charge transport layer coating solution: 45 L / min (film thickness of the formed charge transport layer: 25 μm)

  Table 1 below shows the cyclohexanone content of each coating solution and the viscosity of each coating solution in Comparative Example 2. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 3
Ten electrophotographic photoreceptors of Comparative Example 3 were produced by continuous coating in the same manner as in Comparative Example 1 except that the coating condition (d) in Example 1 was changed from 78 ° to 125 °. Therefore, the atomizing air flow rate and each film thickness at the time of application of each coating liquid are the same as those in Comparative Example 1.

  The cyclohexanone content of each coating solution and the viscosity of each coating solution in Comparative Example 3 are shown in Table 1 below. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 4
Instead of the undercoat layer coating solution of Example 1, the undercoat layer coating solution prepared as follows was used.
That is, 15 parts by weight of alkyd resin (Beckosol 1307-60-EL: manufactured by Dainippon Ink and Chemicals) and 10 parts by weight of melamine resin (Super Becamine G-821-60: manufactured by Dainippon Ink and Chemicals) were added to methyl ethyl ketone 320. Dissolve in parts by weight, add 90 parts by weight of titanium oxide powder (Typer CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) and disperse in a ball mill for 12 hours, take it out in a container, and dilute with 140 parts by weight of methyl ethyl ketone. An undercoat layer coating solution was obtained.
Ten electrophotographic photoreceptors of Comparative Example 4 were produced by continuous coating in the same manner as in Comparative Example 1 except that the undercoat layer coating solution thus obtained was used. Therefore, the atomizing air flow rate and each film thickness at the time of application of each coating liquid are the same as those in Comparative Example 1.

  Table 1 below shows the cyclohexanone content of each coating solution and the viscosity of each coating solution in Comparative Example 4. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 5
Instead of the charge transport layer coating solution of Example 1, a charge transport layer coating solution prepared as follows was used.
That is, 10 parts of bisphenol A type polycarbonate resin and 0.002 part of silicon oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) are dissolved in 100 parts of tetrahydrofuran, and the charge transport material represented by the structural formula (2) is dissolved therein. 8 parts was added and dissolved, and diluted with 50 parts of cyclohexanone to prepare a coating solution for charge transport layer.
Ten electrophotographic photosensitive members of Comparative Example 5 were produced by continuous coating in the same manner as in Comparative Example 1 except that the charge transport coating solution thus obtained was used. Therefore, the atomizing air flow rate and each film thickness at the time of application of each coating liquid are the same as those in Comparative Example 1.

  The cyclohexanone content of each coating solution in Comparative Example 5 and the viscosity of each coating solution are shown in Table 1 below. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Comparative Example 6
Ten electrophotographic photoreceptors of Comparative Example 5 were produced by continuous application in the same manner as in Comparative Example 1 except that the atomizing air flow rate during application of the charge transport layer coating liquid in Comparative Example 1 was 60 L / min. did. Therefore, the film thickness (25 μm) of the charge transport layer, the atomizing air flow rate and the respective film thicknesses during application of the coating solution for the undercoat layer and the coating solution for the charge generation layer are the same as in Comparative Example 1.

  The cyclohexanone content of each coating solution and the viscosity of each coating solution in Comparative Example 6 are shown in Table 1 below. Table 2 below shows the pressure of the atomizing air at the time of coating each layer, the particle size distribution of fine particles sprayed from the spray gun, and the maximum film thickness difference in the film thickness of each layer.

Image Evaluation With respect to the electrophotographic photosensitive members (each 10) obtained in Examples 1 and 2 and Comparative Examples 1 to 6, a remodeled machine (λ == RICOH Co., Ltd., full color laser printer). Using 655 nm, 1200 dpi, and a beam spot of 2.7 × 10 ⁻³ mm ² ), image formation was performed. The quality of the formed image (white solid image, oblique thin line image, halftone image, image abnormality occurrence time) was visually determined. The halftone image is a 2 × 2 dot image. Table 3 shows the image evaluation results.

  From the above evaluation results, the inner surface width (b) of the air cap tip in the spray gun of the present invention, the distance (c) between the air cap leading edge position and the nozzle leading edge position, the taper angle (d) inside the air cap, By adjusting the mutual positional relationship and dimensions of the nozzle and air cap, such as the minimum gap dimension (a) between the air cap inner diameter and the nozzle outer diameter at the tip, the liquid residue is frequently It was confirmed that a spray mist having a stable particle size distribution was sprayed continuously without cleaning, and a uniform coating film with no unevenness could be stably formed on the workpiece.

It is a schematic block diagram of the spray coating apparatus for electrophotographic photoreceptors in this invention. It is the schematic sectional drawing (a) which shows the structural example of the spray gun of FIG. 1, and the schematic sectional drawing (b) of the spray gun tip which shows the state by which the needle was deployed. It is a schematic sectional drawing which shows the name of each part used in order to demonstrate the spray gun in this invention. It is a principal part enlarged view of the spray gun front end for demonstrating the preferable range of the inner surface width (b) of the air cap front-end | tip part in this invention. It is a principal part enlarged view of the spray gun front end for demonstrating the preferable range of the space | interval (c) of the air cap most advanced position and nozzle most advanced position in this invention. It is a principal part enlarged view of the spray gun front end for demonstrating the preferable range of the taper angle (d) inside an air cap in this invention. It is a principal part enlarged view for demonstrating the preferable range of the minimum clearance dimension (a) of the space | gap pinched | interposed into the air cap internal diameter and nozzle outer diameter of each front-end | tip part in this invention. It is a schematic diagram which shows the example of a coating system structure in the case of spray-coating a coating liquid on a workpiece | work using the spray coating apparatus for electrophotographic photoreceptors in this invention. It is principal part sectional drawing for demonstrating each item of the spray coating apparatus used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spray coating apparatus 2 Coating liquid supply means 2A Coating liquid 3 Atomization air supply means 3A Atomization air 4 Spray gun 5 Nozzle 6 Air cap 7 Flow path 8 Discharge port 9 Cavity 10 Discharge port 11 Nozzle tip part 12 Air cap tip Part 13 Nozzle cutting edge position 14 Air cap cutting edge position (a) Minimum gap dimension of the gap sandwiched between the air cap inner diameter and the nozzle outer diameter at each tip (b) Inner width of the air cap tip ( right cylinder Height )
(C) Distance between the leading edge position of the air cap and the leading edge position of the nozzle (d) Taper angle inside the air cap (θ) Taper angle outside the nozzle (e) Distance between the leading edge position of the needle and the leading edge position of the nozzle ( t1) The gap between the inner wall of the nozzle and the outer wall of the needle in the flow path (t2) The most advanced nozzle thickness 51 Work 52 Coating booth 53 Spray gun 54 Guide rail 55 Clean air supply port 56 Exhaust port 57 Coating solution supply means 58 Coating solution Tank 59 Pump 60 Atomizing air supply means 61 Atomizing air tank 62 Pump

Claims (12)

A coating liquid supply means, an atomizing air supply means, a frustoconical nozzle configured to feed the coating liquid and the atomizing air, and a hollow frustoconical shape surrounding the frustoconical nozzle A spray gun having an air cap, and spraying a coating liquid from the spray gun to coat and form at least one layer selected from an undercoat layer, a charge generation layer, and a charge transport layer on an object to be coated. In the spray coating apparatus for the electrophotographic photosensitive member,
Wherein the nozzle discharge opening is provided with a flow path for feeding a coating liquid, air gap and an outlet for feeding the atomizing air between said nozzle and said air cap is provided,
Inside the air cap facing said Nozzle constitutes said space straight cylindrical extending from the outlet of the atomizing air and the straight cylindrical truncated cone shaped space portion extending from the space Shape,
The spray coating apparatus for an electrophotographic photosensitive member, wherein a height of the right circular cylinder in the right circular cylindrical space is 0.1 mm or more and 0.3 mm or less .   2. The electrophotographic photosensitive member according to claim 1, wherein the front end position of the air cap front end opening portion is arranged and configured so as to be the same as or the front surface with respect to the front end position of the nozzle front end portion. Spray coating equipment. The open angle of an inner inclined cylindrical surface forming the frustoconical space in the air cap having a hollow frustoconical shape facing the nozzle is 80 ° or more and 120 ° or less. 2. A spray coating apparatus for an electrophotographic photosensitive member according to 1.   The minimum clearance dimension of the space | gap pinched by the air cap inner peripheral wall surface of the said air cap front-end | tip part and the nozzle outer peripheral wall surface of a nozzle front-end | tip part is 0.2 mm or more and 1.0 mm or less, The spray coating apparatus for electrophotographic photoreceptors as described. A coating liquid supply means, an atomizing air supply means, a frustoconical nozzle configured to feed the coating liquid and the atomizing air, and a hollow frustoconical shape surrounding the frustoconical nozzle A spray coating apparatus for an electrophotographic photosensitive member having a spray gun having an air cap is used, and a coating liquid is sprayed from the spray gun to form an undercoat layer, a charge generation layer, and a charge on the substrate. A method for producing an electrophotographic photosensitive member by coating and forming at least one layer selected from transport layers ,
Feeding the coating solution from the flow path and a discharge port provided in the nozzle, while discharging, the atomizing air feeding, and discharged from the gap between the discharge port provided between said nozzle and said air cap, Spray and apply the coating liquid as fine particles ,
The inner side of the air cap facing the nozzle forms a right columnar space extending from the atomizing air outlet and a frustoconical space extending from the right columnar space. And
The method for producing an electrophotographic photosensitive member, wherein a height of the right circular cylinder in the right circular cylindrical space is 0.1 mm or more and 0.3 mm or less .   6. The electrophotographic photosensitive member according to claim 5, wherein the front end position of the air cap front end opening portion is arranged and configured to be the same as or the front surface with respect to the front end position of the nozzle front end portion. Manufacturing method. The open angle of an inner inclined cylindrical surface forming the frustoconical space in the air cap having a hollow frustoconical shape facing the nozzle is 80 ° or more and 120 ° or less. 6. A method for producing an electrophotographic photosensitive member according to 5.   6. The minimum gap dimension of a gap sandwiched between an air cap inner peripheral wall surface of the air cap tip and a nozzle outer peripheral wall surface of a nozzle tip is 0.2 mm or more and 1.0 mm or less. A method for producing the electrophotographic photosensitive member according to the description.   The electrophotographic photosensitive member according to any one of claims 5 to 8, wherein the pressure of the supplied atomizing air is 0.01 MPa or more and 0.5 MPa or less immediately before being introduced into the spray gun. Method.   The solvent used in the coating solution is a mixed solvent, and the mixed solvent contains a solvent having a vapor pressure of 0.1 to 20 mmHg at least at 20 ° C., and the content is 10 wt% or more and 70 wt% or less. The method for producing an electrophotographic photoreceptor according to claim 5, wherein the electrophotographic photoreceptor is provided.   The particle size distribution of the coating liquid fine particles sprayed by the atomizing air from the spray gun is 1 μm or more and 30 μm or less (measurement standard: D90 μm) immediately before adhering to the object to be coated. 9. The method for producing an electrophotographic photosensitive member according to any one of 8 above.   The method for producing an electrophotographic photosensitive member according to claim 5, wherein the coating solution has a viscosity of 0.01 mPa · s or more and 5 mPa · s or less.

Images