JPH11276958A - Method and device for coating coating material on cylindrical base and production of photosensitive body drum for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently form a uniform coating film on the outer peripheral surface of a cylindrical base by simple control. SOLUTION: In a method for coating a coating material on the cylindrical base for applying the coating material fed to a coating roll 2 on the cylindrical base 1, the film thickness of the coating material 5 fed to the coating roll 2 is uniformalized with a metering roll 3, and also, the coating material is applied while the cylindrical base 1 and the coating roll 2 are rotated in the same direction, then the coated cylindrical base 1 is separated from the coating roll 2. At this time, a separating speed between the cylindrical base 1 and the coating roll 2 is made into <=5 mm/s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for applying paint to a cylindrical substrate, and a method for manufacturing a photosensitive drum for electrophotography.

[0002]

2. Description of the Related Art An electrophotographic photosensitive drum is provided with an undercoat layer, a charge generation layer, and a charge transport layer, which are sequentially coated and laminated on an outer peripheral surface of a hollow cylindrical substrate made of aluminum as an electrophotographic photosensitive body paint. In some cases, a photosensitive layer is formed.
The photosensitive layer is required to be a thin film and have a uniform thickness. However, since there is a strong demand for cost reduction, development and study of a coating method having excellent productivity are being conducted. As a method of forming a photosensitive layer by applying an electrophotographic photoreceptor paint to the outer peripheral surface of a cylindrical substrate, there have been conventionally known methods such as a spray coating method, a dip coating method, and a blade coating method. However, the conventional coating method has drawbacks such as a failure to obtain a uniform coating film and poor production efficiency.

For example, in the spray coating method, if a solvent having a low boiling point is used for the electrophotographic photoreceptor paint, the solvent contained in the paint volatilizes while the paint reaches the outer peripheral surface of the cylindrical substrate, and the solid content of the paint is reduced. Due to the increased concentration, when it reaches the cylindrical substrate, it does not spread sufficiently to the outer peripheral surface, and the coating surface becomes uneven, and the coating surface cannot be smooth and a uniform coating cannot be obtained. was there.

Conversely, when a solvent having a high boiling point is used, the paint adheres to the outer peripheral surface of the cylindrical substrate and leveling (uniformity of the film thickness, the same applies hereinafter) occurs. Fixation is delayed. Therefore, if the application is continued in a state where the coating is not sufficiently fixed, if the desired film thickness is large, paint dripping occurs, and a coating film having a uniform film thickness cannot be obtained. In order to avoid this, it is conceivable to apply the paint by dividing it into several times.However, it is conceivable to apply and dry the paint until it is dry to the touch (to the extent that no trace remains even when touched with a finger) It was necessary to repeatedly obtain a desired film thickness, which was time-consuming and extremely complicated.

According to the dip coating method, the smoothness of the surface of the coating film is improved, but the coating film is formed inside or on the end surface of the cylindrical substrate. Since the coating film formed on the inside or the end face of the cylindrical base becomes an obstacle when attaching a flange or the like, when the cylindrical base is used as a photosensitive drum for electrophotography, the coating on the inside or the end face of the cylindrical base is required. Once formed, the coating must be peeled off. Further, depending on the model used, the coating film once formed on the outer peripheral end of the cylindrical substrate must be peeled off, which requires a peeling step, which is a factor that hinders productivity.

Further, the thickness of the coating film is largely controlled by the physical properties of the coating material and the pulling speed after immersion. When the coating film is pulled at a constant speed, a difference in film thickness occurs between the upper end and the lower end of the cylindrical substrate. In order to solve this, it is necessary to control the pulling speed, but it is difficult to control it, and furthermore, it is necessary to slow down the pulling speed after immersion in order to form a uniform coating film. There was a problem, and high production efficiency could not be obtained.

[0007] The blade coating method is a coating method in which a blade is arranged at a position close to the longitudinal direction of a cylindrical substrate, paint is supplied to the blade, the cylindrical substrate is rotated once, and then the blade is retracted. Although high productivity can be obtained by this method, when the blade is retracted, there is a disadvantage that the coating applied to the cylindrical substrate partially rises due to the surface tension of the coating, so that the film thickness becomes uneven.

[0008] Furthermore, there is a roll coating method as a method other than the above method. The roll coating method is special in that the object to be coated is a cylindrical substrate, that is, the coating is performed once by rotating the cylindrical substrate as the object to be coated. The returned surface repeatedly returns to the application section, causing a problem that a paint pool is generated and the film thickness becomes non-uniform.

In order to avoid the occurrence of this paint pool,
For example, in Japanese Patent Application Laid-Open No. Hei 3-12261, when the cylindrical substrate makes one rotation and the coating is applied to the entire outer periphery thereof,
It has been proposed to separate the cylindrical substrate from the roll.
However, this requires fairly complex and precise control, and if the cylindrical body only makes one revolution,
It is difficult to obtain a uniform coating.

[0010] Further, in the same publication, after the coating is completed by rotating the drum one or more rotations, the drum is separated from the paint supply roll, and the drum is continuously rotated to level the coating film surface (uniform film thickness). However, in this method, precise film thickness control must be performed in anticipation of the amount of paint pool to be leveled in advance.

[0011] Japanese Patent Application Laid-Open No. 2-222743 also discloses that
There is disclosed a method in which a coating film formed on the peripheral surface of a paint supply cylindrical roll is transferred only one layer to the peripheral surface of a cylinder to be coated, and the contact between the cylindrical substrate and the paint supply cylindrical roll is cut off. As described above, complicated and precise control is required.

[0012]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional coating method, and forms a uniform coating film efficiently on the outer peripheral surface of a cylindrical substrate by a simple control in a roll coating method. This is to provide a method for doing so.

[0013]

Means for Solving the Problems The present inventors have intensively studied a roll coating method in view of the above-mentioned situation, and found that in order to improve the uniformity of a coating film formed on a cylindrical substrate, a coating roll was used. It has been found that it is effective to control the speed at which the cylindrical substrate is separated in separating the cylindrical substrate from the application roll after forming the coating film on the cylindrical substrate by the method described above.

Further, after the gap between the cylindrical substrate and the application roll is set to be at least twice the thickness of the coating material to be formed on the cylindrical substrate, the coating is applied, and then the gap between the applied cylindrical substrate and the application roll is set. The liquid film of the formed paint is broken, and by controlling the separation speed within the moving distance until the applied cylindrical substrate is completely separated from the application roll, the coating film formed on the cylindrical substrate is controlled. It was also found that the uniformity could be further improved. Furthermore, when the coated cylindrical substrate separates from the application roll, the moving direction is important for the separation, and the inclination formed between the axis of the cylindrical substrate and the axis of the application roll. Is also important. Here, the paint film thickness means the paint film thickness before the volatile component evaporates, that is, at the time of application.

The present invention is based on the above findings,
In a method of applying a coating material supplied to an application roll to a cylindrical substrate, the coating layer supplied to the application roll is coated on the cylindrical substrate while rotating the cylindrical substrate and the application roll. The object has been solved by applying a coating material to the outer peripheral surface and separating the cylindrical substrate and the application roll at a separation speed of 5 mm / s or less when separating the cylindrical substrate and the application roll. Furthermore, the present invention, when separating the cylindrical substrate and the application roll, the separation speed between the cylindrical substrate and the application roll,
It can be 0.1 mm / s or more.

In order to form a coating film having a uniform thickness on the cylindrical substrate, the present inventor has to rotate the cylindrical substrate and the application roll in the same direction, It has been found that it is effective to make the film thickness uniform. Therefore, according to the present invention, it is possible to perform the coating while rotating the cylindrical substrate and the application roll in the same direction. The uniformity of the coating film formed on the substrate can be improved. Also, the present invention provides a method of manufacturing a device, wherein the gap between the cylindrical substrate and the coating roll is set to be at least twice the thickness of a coating film formed on the outer periphery of the cylindrical substrate, and the coating material between the gaps is separated when the cylindrical substrate is separated. A technique for preventing the film thickness of the paint applied to the cylindrical substrate from being more adhered to the substrate and preventing the film thickness from becoming uneven, and, when separating the cylindrical substrate and the application roll, the cylindrical substrate is removed from the cylindrical substrate. Technology to prevent the unevenness in the paint applied at the time of separation of the cylindrical substrate, and to separate the cylindrical substrate and the application roll from each other, It is possible to select a technique in which the axis of the cylindrical substrate and the axis of the application roll are separated in an inclined state to prevent unevenness in the coating applied when the cylindrical substrate is separated.

Further, the apparatus for applying paint to a cylindrical substrate according to the present invention comprises a rotatable application roll for supplying a paint and applying the paint to the cylindrical substrate; It is possible to have a gripping device capable of adjusting the separation speed between the cylindrical substrate and the application roll to 5 mm / s or less when the cylindrical substrate and the application roll are separated from each other. When separating the coating roll, the cylindrical substrate, a technology capable of separating in a direction oblique to the axial direction of the cylindrical substrate, or a gripping device, when separating the cylindrical substrate and the coating roll, A technique that allows the axis of the cylindrical substrate and the axis of the application roll to be separated in an inclined state, and a technique for supplying the coating with a uniform film thickness to the application roll that is disposed close to the outer circumference of the application roll for a predetermined distance. It is possible to adopt a technology that has means for measuring paint It is.

Further, according to the present invention, the electrophotographic photosensitive drum substrate and the application roll are disposed close to each other, and the electrophotographic photosensitive material supplied to the application roll is applied to the electrophotographic photosensitive drum substrate. In the method of manufacturing a photosensitive drum for electrophotography to be dried, a coating layer supplied to a coating roll with a uniform film thickness by a paint measuring means is rotated by rotating the coating roll with the electrophotographic photosensitive drum base in the same direction. An electrophotographic photoreceptor paint is applied on the outer peripheral surface of the photoreceptor drum base, and when the applied electrophotographic photoreceptor drum base is separated from the coating roll, the electrophotographic drum base and the coating roll are separated. It is possible to provide a method for manufacturing an electrophotographic photosensitive drum having a separation speed of 5 mm / s or less. In addition,
In the present invention, the term “close” means a state in which the cylindrical substrate and the application roll are in contact with each other via the paint, and the term “separation” means that the paint formed between the cylindrical substrate and the application roll and the like. This means a state in which the liquid film is broken, the applied cylindrical substrate is completely separated from the application roll and the like, and the close state is released. Therefore, in the present invention, the separation speed is defined as a value within a moving distance until the coating liquid film formed between the cylindrical substrate and the application roll is broken and the cylindrical substrate and the application roll are completely separated from each other. It means moving speed.

Hereinafter, the method and apparatus for applying a coating material to a cylindrical substrate and the method for producing a photosensitive drum for electrophotography according to the present invention will be described in detail. First, in the present invention, a cylindrical substrate and a coating roll (hereinafter referred to as an applicator roll)
Will be described with reference to FIGS. 8 and 9.

8 and 9, reference numeral 1 denotes a cylindrical substrate as an object to be coated, and 2 denotes an applicator roll, each of which rotates in the direction of an arrow (solid line). That is, FIG. 8 shows a case where the cylindrical base 1 and the applicator roll 2 rotate in the same direction, and FIG. 9 shows a case where the cylindrical base 1 and the applicator roll 2 rotate in the opposite directions. I have. The coating material 5 is affected by the rotation direction of the cylindrical substrate 1 and the applicator roll 2, and flows in the directions of the arrows (chain lines).

As shown in FIG. 9, when the cylindrical substrate 1 and the applicator roll 2 rotate in opposite directions, the paint 5 applied to the cylindrical substrate 1 at the transition starting point 91 passes through the transition end point 92. It returns to the transition starting point 91 with the rotation of the cylindrical substrate 1. Therefore, a part of the paint 5 successively supplied by the applicator roll 2 cannot pass through the gap between the cylindrical substrate 1 and the applicator roll 2. The paint 5 that cannot pass is accumulated near the transition starting point 91 and forms a paint pool 8. When the cylindrical substrate 1 is separated from the applicator roll 2 in this state, a portion corresponding to the paint pool 8 protrudes and impairs the uniformity of the coating film. It is conceivable to separate the cylindrical substrate 1 from the applicator roll 2 before the paint pool 8 is formed, but in this case, the coating cannot be uniformly applied to the outer peripheral surface of the cylindrical substrate 1.

On the other hand, if the rotation direction of the cylindrical base 1 and the applicator roll 2 is set to the same direction as shown in FIG. That is, most of the paint conveyed by the applicator roll 2 reaches the transfer end point 92 from the arrow (chain line) transfer start point 91 along with the rotation of the cylindrical base 1 via the outer peripheral surface of the cylindrical base 1. . Therefore, even if the paint continues to be transferred from the applicator roll 2 to the cylindrical substrate 1, the paint pool 8 does not occur at the transfer start point 91. A small amount, if any, is generated and the applicator roll 2
The leveling after the separation of the cylindrical substrate 1 from the substrate can be resolved to such an extent that the function is not hindered.

By setting the rotation direction of the cylindrical substrate 1 and the applicator roll 2 in the same direction, it is possible to prevent or suppress the occurrence of paint accumulation. However, the uniformity of the coating film formed on the outer periphery of the cylindrical substrate 1 is promptly increased. It is important to make the coating supplied to the applicator roll 2 uniform in film thickness. That is, it is extremely difficult to form a uniform coating film on the outer peripheral surface of the cylindrical substrate 1 if the cylindrical substrate 1 makes one rotation after starting contact with the paint on the outer peripheral surface of the applicator roll 2. A number of rotations are required. However, since the number of rotations affects the production efficiency, it is desirable to form a coating film having a uniform film thickness at the lowest possible number of rotations. In order to form a uniform coating film on the outer peripheral surface of the cylindrical substrate 1 at a lower rotation speed, it is effective to make the thickness of the coating film on the outer peripheral surface of the applicator roll 2 uniform. A method for making the thickness of the coating film on the outer peripheral surface of the applicator roll 2 uniform will be described later. However, if the applicator roll 2 is immersed in the coating and the coating is applied to the outer peripheral surface thereof, the cylindrical substrate 1 It is difficult to quickly form a uniform coating film.

Also, a cylindrical substrate 1 and an applicator roll 2
The uniformity of the coating film formed on the outer periphery of the cylindrical substrate 1 can be promptly obtained by making the rotation directions of the coatings the same direction and making the thickness of the coating material supplied to the applicator roll 2 uniform. However, after the transfer of paint from the applicator roll 2 to the cylindrical substrate 1 to form a coating film, the applied cylindrical substrate 1 is removed from the applicator roll 2.
It is also important to control the separation speed within the moving distance until the cylindrical substrate 1 completely separates from the applicator roll 2 at a very low speed when separating from the applicator roll 2. The reason will be described with reference to FIGS. 10, 11, 12, and 13.

In FIGS. 10, 11, 12 and 13, reference numeral 1 denotes a cylindrical substrate as an object to be coated, and 2 denotes an applicator roll, each of which rotates in the direction of an arrow (solid line). The coating material 5 is affected by the rotating direction of the cylindrical substrate 1 and the applicator roll 2, and flows in the directions of the arrows (chain lines).

As shown in FIG. 12, when the cylindrical substrate 1 and the applicator roll 2 are rotated in the same direction as each other, the paint accumulation does not occur as described above, or the paint accumulation is small even if it occurs. When the cylindrical substrate 1 and the applicator roll 2 are rapidly separated from each other, an uneven portion (projection portion) is likely to occur in the coating film on the cylindrical substrate 1 as shown in FIG. At the transition starting point 91 and the transition end point 92 of the coating material 5 between the applicator roll 2 and the cylindrical substrate 1, a meniscus is formed between the cylindrical substrate 1 and the applicator roll 2 where the coating material is separated to form the cylindrical substrate 1. Since the amount of paint is larger than that of other portions of the upper coating film, the coating is smoothed by leveling after separation, but tends to remain.

A cylindrical substrate 1 and an applicator roll 2
Is smaller than twice the paint film thickness calculated from the desired dry film thickness and the nonvolatile content ratio of the paint 5,
The paint existing in the gap between the cylindrical substrate 1 and the applicator roll 2 is divided between the cylindrical substrate 1 and the applicator roll 2 when separated and adheres to the applicator roll 2 in large quantities. However, the thickness of the coating material in other portions of the cylindrical substrate 1 becomes thinner.

FIG. 10 shows a state in which the cylindrical substrate 1 is separated from the applicator roll 2 at a low speed from the state shown in FIG. FIG. 2 schematically shows a state in which the sheet is being stretched thinly and rotating in the same direction. As the cylindrical substrate 1 continues to separate from the applicator roll 2 at a low speed, the thinly-stretched liquid film of the paint between the cylindrical substrate 1 and the applicator roll is finally cut off as shown in FIG. The state shown in FIG. Cut cylindrical substrate 1 and applicator roll 2
Is present as slight swells on the coatings on both the cylindrical substrate 1 and the applicator roll 2, but the swelling of the coatings on the applicator rolls 2 (2) Disappears in a gap with a paint measuring means such as a metering roll provided on the outer periphery, and the swelling of the coating film on the cylindrical substrate 1 disappears promptly by the leveling action. Thereby, the uniformity of the coating film formed on the outer periphery of the cylindrical substrate 1 is further improved.

In the state of application to the cylindrical substrate shown in FIG. 12, the gap between the cylindrical substrate 1 and the applicator roll 2 is set to be at least twice the thickness of the paint to be formed on the cylindrical substrate 1. It is possible to prevent a portion thinner than the coating film thickness of the other portion of the cylindrical substrate 1 due to the division of the coating film in the gap between the cylindrical substrate 1 and the applicator roll 2 at the time of separation. it can. Further, since the coating liquid film between the cylindrical substrate 1 and the applicator roll 2 is broken with a small moving distance, the time required for separating the cylindrical substrate 1 from the applicator roll 2 at a low speed can be reduced. it can.

The cylindrical substrate 1 is applied to an applicator roll 2
When the paint in the paint pool formed between the cylindrical substrate 1 and the applicator roll 2 cuts the liquid film of the stretched paint at a low speed, the shaft of the cylindrical substrate 1 that separates The direction in which the core moves is separated in a direction oblique to the axial direction of the cylindrical substrate 1 at the time of coating, so that the core can move smoothly, or the coating film formed on the outer peripheral surface of the cylindrical substrate 1 can be uniform. Improve the performance.

Further, when the cylindrical substrate 1 and the applicator roll 2 are separated from each other, the axis of the cylindrical substrate 1 and the axis of the applicator roll 2 are separated in an inclined state. The axis of the cylindrical substrate 1 is separated from the axis of the applicator roll 2 in an inclined state that is slightly inclined instead of being parallel to the axis of the applicator roll 2, or the coating is formed on the outer peripheral surface of the cylindrical substrate 1. Improve the uniformity of

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for applying a paint to a cylindrical substrate and a method of manufacturing a photosensitive drum for electrophotography according to the present invention will be described below with reference to the drawings.
1 and 2 are a perspective view and a side view, respectively, showing an embodiment of the present invention. 1 and 2, reference numeral 1 denotes a cylindrical substrate as an object to be coated, 2 denotes an application roll (applicator roll), 3 denotes a paint measuring unit (metering roll), 4 denotes a cleaning doctor, 5 denotes a paint, and 6 denotes a paint. Measuring means, 9 is a gripping device, and 52 is a paint tank.

The cylindrical base 1, the applicator roll 2, and the metering roll 3 are installed so as to be rotatable in the direction of the arrow by a rotating mechanism (not shown). Further, the cylindrical substrate 1
The applicator roll 2 and the applicator roll 2 are disposed close to each other with a gap capable of transferring the paint from the applicator roll 2 to the cylindrical substrate 1, and a part of the metalling roll 3 is added to the paint 5 in the paint tank 52. The immersed applicator roll 2 and the applicator roll 2 are disposed close to each other with a gap equal to or greater than the gap capable of transferring the paint from the applicator roll 2 to the cylindrical substrate 1. The cylindrical substrate 1 is gripped by a gripping device 9 connected to a rotating mechanism (not shown) and capable of approaching and separating from the applicator roll 2. The gripping device 9 has a rotatable rotation mechanism connected to a moving device, and controls a position state, a rotation direction, a separation direction, a separation state, and the like between the cylindrical substrate 1 and the applicator roll 2 as described later. It can be controlled.

The applicator roll 2, which is partially immersed in the paint 5 in the paint tank 52, is rotated in the direction of the arrow. It is supplied to the outer peripheral surface of the applicator roll 2 through the gap with the metering roll 3,
The coating material 5 supplied to the applicator roll 2 is measured by passing through the gap having a constant width. Excess paint 5 scraped off by the metalling roll 3 is completely scraped off by the cleaning blade 4 as the metalling roll 3 rotates, and returns to the paint tank 52 again. By rotating the applicator roll 2 and the metering roll 3 in the direction of the arrow in this state, the thickness of the paint 5 on the outer peripheral surface of the applicator roll 2 becomes uniform, so that the coating 5 is applied to the outer peripheral surface of the cylindrical substrate 1. The thickness of the paint also becomes uniform quickly. In the above embodiment, the metering roll 3 is rotated, but may be fixed without rotating.

In the above embodiment, the metering roll 3
Is used to make the thickness of the paint 5 on the outer peripheral surface of the applicator roll 2 uniform, but as shown in FIG. 3, the applicator roll 2 is immersed in the paint 5 stored in the paint tank 52, May be disposed on the applicator roll 2 through a gap having a predetermined width. In this state, by rotating the applicator roll 2,
The thickness of the paint 5 on the outer peripheral surface of the applicator roll 2 is made uniform.

Further, as shown in FIG. 4, a plate-shaped paint measuring means 61 is disposed in a tangential direction of the applicator roll 2 with a gap having a predetermined width, or a step is formed on the outer periphery of the cylindrical body as shown in FIG. Is disposed between the applicator roll 2 and the applicator roll 2 via a gap having a predetermined width. Alternatively, the column-shaped paint measuring means 63 having an elliptical section in cross section as shown in FIG. It is also possible to dispose via a gap having a predetermined width.
Paint measuring means 61, 62, 63 shown in FIGS.
According to the method, the uniformity of the film thickness of the coating material 5 can be improved more than the gap setting doctor 6 shown in FIG.

As another method, as shown in FIG. 7, a pickup roll 7 is placed in a paint 5 stored in a paint tank 52.
And the paint 5 transferred from the pick-up roll 7 to the applicator roll 2 is measured and supplied in a gap between the applicator roll 2 and the metering roll 3 disposed close to the applicator roll 2. is there. In this case, the cleaning doctor 4 can be installed on the metering roll 3 to return the excess paint 5 to the paint tank 52. In this state, by rotating the applicator roll 2, the metering roll 3, and the pickup roll 7 in the direction of the arrow, the thickness of the paint on the outer peripheral surface of the applicator roll 2 is made uniform.

Although it has been described above that the cylindrical substrate 1 and the applicator roll 2 are in contact with each other via the paint, the specific gap width depends on the type of paint to be applied and the cylindrical shape. The thickness may be set in the range of 10 μm to 2000 μm and a value equal to or less than the gap width between the applicator roll 2 and the paint measuring means 6 depending on the film thickness to be finally formed on the substrate 1. Setting the gap width between the cylindrical substrate 1 and the applicator roll 2 to be twice or more the thickness of the paint film to be formed on the cylindrical substrate 1 requires a uniform coating film on the cylindrical substrate 1. It is more preferable from the viewpoint of shortening the separation time between the applicator roll 2 and the cylindrical substrate. Further, the gap width between the applicator roll 2 and the paint measuring means 6 is also 10 μm to 10 μm depending on the kind of paint to be applied and the film thickness finally formed on the cylindrical substrate 1.
What is necessary is just to set in the range of 2000 micrometers.

The peripheral speed of rotation of the cylindrical substrate 1 when the coating material is applied should be in the range of 3 m / min to 50 m / min, and the peripheral speed of rotation of the applicator roll 2 should be 3 m / min.
It is preferable to set the range of min to 50 m / min.
When the peripheral speed of the cylindrical substrate 1 and the applicator roll 2 is low, the uniformity of the coating film formed on the outer peripheral surface is insufficient, and it takes a long time until the coating film is formed on the outer periphery of the cylindrical substrate 1. On the contrary, if the peripheral speed is too high, the paint may be scattered by the centrifugal force.

The ratio of the peripheral speed of rotation of the cylindrical substrate 1 to the peripheral speed of rotation of the applicator roll 2 (the peripheral speed of the cylindrical substrate 1 / the peripheral speed of the applicator roll 2) is 0.5 to 2.0. Is preferable, and the range of 0.6 to 1.5 is more preferable. The ratio of the diameter of the applicator roll 2 to the diameter of the cylindrical substrate 1 is 1
If it is in the range of / 4 to 10, the present invention can be practiced without any problem.

In the coating method of the present invention, one layer of paint is applied to the outer peripheral surface of the cylindrical substrate 1, in other words, the cylindrical substrate 1
It is not preferable to separate from the applicator roll 2 at the time when the. That is, the applicator roll 2
This is because the paint starts to transfer to the outer peripheral surface of the cylindrical substrate 1 and the coating film made of the paint is uniformly formed on the outer peripheral surface of the cylindrical substrate 1 only after the cylindrical substrate 1 rotates several times. Therefore, the cylindrical substrate 1 is separated from the applicator roll 2 after the cylindrical substrate 1 has rotated several times to form a uniform coating film. In the present invention, since the coating material on the outer peripheral surface of the applicator roll 2 is made uniform, the coating film of the coating material on the outer peripheral surface of the cylindrical substrate 1 can be made uniform with less rotation.

The speed at which the cylindrical substrate 1 having the coating applied uniformly on the outer peripheral surface thereof is separated from the applicator roll 2 is extremely important because if it is too high, the uniformity of the coating film obtained by the angle coating is impaired. . That is, a meniscus of the paint is formed between the gap between the cylindrical substrate 1 and the applicator roll 2 during the application as shown in FIG.
As shown in (2), when the separation speed after the application is high, the cylindrical substrate 1 remains partially disturbed even after separation from the applicator roll 2, and is slightly reduced by leveling after separation. However, this results in loss of uniformity of the coating.

On the other hand, when the speed of separating the cylindrical substrate 1 from the applicator roll 2 after coating is low, as shown in FIG. 10, the gap between the cylindrical substrate 1 and the applicator roll 2 during coating is reduced. The meniscus portion of the paint formed on the substrate 1 is stretched as a thin film of the paint as the gap between the cylindrical substrate 1 and the applicator roll 2 is enlarged, and is finally broken to the state shown in FIG. Since the amount of the paint on the meniscus portion is very small, the paint disappears due to the leveling action of the coating film.

The speed at which the cylindrical substrate 1 is separated from the applicator roll 2 after coating is preferably 5 mm / s or less and 0.3 mm / s or more with respect to the position of the cylindrical substrate 1 at the time of coating. , And more preferably 2 mm / s. This separation speed may be maintained until the breakage of the liquid film of the paint between the applied cylindrical substrate 1 and the applicator roll 2 is completed. Desirable.

In order to obtain a uniform coating film on the outer peripheral surface of the cylindrical substrate 1, the applied cylindrical substrate 1 is applied to an applicator roll 2.
In addition to controlling the speed of separation, the paint in the meniscus portion formed between the cylindrical substrate 1 and the applicator roll 2 is thinly stretched to break the paint thin film formed under certain conditions. It is also important. If the breakage of the thin film occurs partially in the cylindrical substrate 1 instead of all at once in the axial direction, or if the cutting occurs in one direction but the moving speed of the cutting portion is not constant, the axis of the cylindrical substrate 1 This is because a band-like or streak-like coating film unevenness occurs in the direction.

In order to cut a thin film of paint formed between the cylindrical substrate 1 and the applicator roll 2 under a certain condition, it is effective to apply a uniform force from the outside with the separation. is there

As shown in FIG. 16 (a), the surface on which the cylindrical substrate 1 moves away after the coating is finished is a plane including the axis of the cylindrical substrate 1 and the axis of the applicator roll 2 at the time of coating. Can be set at an angle in a range of ± 90 degrees with respect to a plane α intersecting with the axis of the cylindrical substrate 1. In order to break the thin film of paint thinly stretched in the gap between the cylindrical substrate 1 and the applicator roll 2 at a uniform speed, the direction in which the cylindrical substrate 1 is separated from the cylindrical substrate 1 is
Is desirably in a direction oblique to the axis of the cylindrical substrate 1 at the time of coating as indicated by an arrow T in FIG.

As shown in FIG. 17, the moving surface of the cylindrical substrate 1 that is separated after the coating is completed is the cylindrical substrate 1 at the time of coating.
If the direction of movement is 90 degrees with respect to the axis of the cylindrical substrate 1 at the time of application, the cylindrical substrate 1 and the In order to break the thin film of paint thinly stretched in the gap with the tarol 2 at a uniform speed, the axis of the separated cylindrical base 1 is inclined by an angle δ with respect to the axis of the applicator roll 2. Is preferred.

As shown in FIG. 18, the surface on which the cylindrical substrate 1 moving away after the coating is completed is moved to the cylindrical substrate 1 at the time of coating.
May be a cylindrical curved surface β that is the closest position. The direction in which the cylindrical substrate 1 separates is such that the cylindrical substrate 1 moves to break at a uniform speed a thin film of paint that has been thinly stretched in the gap between the cylindrical substrate 1 and the applicator roll 2. In the surface β to be formed, the direction is preferably an oblique direction with respect to the axis of the cylindrical substrate 1 at the time of coating as indicated by an arrow R in FIG.

The cylindrical substrate 1 which is separated after the coating is completed.
Moves on the cylindrical curved surface β where the position of the cylindrical substrate 1 at the time of coating is the closest position, and FIG.
When the direction of movement is 90 degrees with respect to the axis of the cylindrical substrate 1 at the time of coating, as shown by an arrow Y 'in FIG.
As shown in FIG. 7 (b), in order to break the thin film of the paint thinly stretched in the gap between the cylindrical substrate 1 and the applicator roll 2 at a uniform speed, the axis of the cylindrical substrate 1 It is preferable to separate the axis of the applicator roll 2 in an inclined state.

In order to continuously supply, apply and separate a plurality of cylindrical substrates 1 to the applicator roll 2, as shown in FIG. The surface on which 1 moves is the cylindrical substrate 1 during coating.
18A, and a plane γ orthogonal to a plane including the axis of the cylindrical substrate 1 and the axis of the applicator roll 2 is separated from each other, or as shown in FIG. It is advantageous to separate the cylindrical substrate 1 from the position on the cylindrical curved surface β having the closest contact point.

Further, after the cylindrical substrate 1 is separated from the applicator roll 2, the rotation of the cylindrical substrate 1 is continued by leveling and air-drying the formed coating film, and the coating film is fixed even if the rotation is stopped. After it is turned into a state where film dripping does not occur, it is put into a hot air circulation type drier and dried completely.

When a solvent having a relatively high volatility is used, a container or a shielding wall in which the applicator roll portion, the cylindrical base portion, or the entire periphery thereof is substantially closed to prevent drying due to the solvent volatilization. It is also effective to cover with such as.

Examples of the material of the cylindrical substrate 1 include metals such as aluminum, iron, copper, manganese, silicon, magnesium, zinc, stainless steel, chromium, titanium, nickel, molybdenum, vanadium, indium, gold, platinum and the like. Or a material obtained by depositing a conductive material such as aluminum on a resin such as an alloy of polyester or the like. However, the present invention is not limited thereto.

When the cylindrical substrate 1 is intended for an electrophotographic photosensitive drum, the photosensitive layer to be formed is a single layer type in which the charge generation material and the charge transport material are present in the same layer. Alternatively, it may be a stacked type in which a layer containing a charge generating material and a layer containing a charge transporting material are stacked.

The single-layer type photosensitive layer can be formed by applying a coating solution in which a charge generating material and a charge transporting material are dispersed or dissolved in a binder resin solution to the outer peripheral surface of a cylindrical substrate and then drying.

The laminate type photosensitive layer is formed by applying a coating material in which fine particles of a charge generating material are dispersed in a binder resin solution as needed to the outer peripheral surface of the cylindrical substrate 1 and then drying to form a charge generating layer. Then, a coating material in which a compound having a charge transport function is dissolved in a binder resin solution is applied and dried to form a charge transport layer. Conversely, the charge generation layer may be formed after forming the charge transport layer on the outer peripheral surface of the cylindrical substrate 1.

The thickness of the photosensitive layer in the electrophotographic photosensitive member is 5 to 50 μm in the case of a single-layer type electrophotographic photosensitive member.
Is preferable, and the range of 15 to 40 μm is particularly preferable.

In the case of a laminated electrophotographic photosensitive member, the thickness of the charge generation layer is preferably 5 μm or less.
The range of 01 to 1 μm is particularly preferred, and the thickness of the charge transport layer is preferably in the range of 5 to 50 μm, and particularly preferably in the range of 15 to 40 μm.

Examples of the charge generating material include phthalocyanine pigments, azo pigments, quinone pigments, perylene pigments, indigo pigments, thioindigo pigments, bisbenzimidazole pigments, quinacridone pigments, quinoline pigments, and lakes. Pigments, azo lake pigments, anthraquinone pigments, oxazine pigments, dioxazine pigments, triphenylmethane pigments, azurenium dyes, squararium dyes, pyrylium dyes, triallylmethane dyes, xanthene dyes, thiazine dyes, cyanine dyes, etc. Examples include various organic pigments and dyes, and inorganic materials such as amorphous silicon, amorphous selenium, tellurium, selenium-tellurium alloy, cadmium sulfide, antimony sulfide, zinc oxide, and zinc sulfide.

The charge generating substance is not limited to those listed here, and may be used alone or
More than one kind can be mixed and used. In the case of a charge generation layer formed by applying a dispersion liquid in which fine particles of the charge generation material are dispersed in a binder resin solution as needed, and drying the dispersion,
The use ratio of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10 by weight, and 6: 1 to 1: 1.
A range of 2 is more preferred.

As the charge transporting material, a hole transporting material and / or an electron transporting material can be used. Examples of the hole transport material include low molecular weight compounds such as pyrene, carbazole, hydrazone, oxazole, oxadiazole, pyrazoline, arylamine, arylmethane, benzidine, thiazole, and stilbene. And butadiene compounds. Examples of the polymer compound include poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, and ethylcarbazole-. Formaldehyde resin, triphenylmethane polymer, polysilane and the like can be mentioned.

Examples of the electron transporting material include organic compounds such as benzoquinone, tetracyanoethylene, tetracyanoquinodimethane, fluorenone, xanthone, phenanthraquinone, phthalic anhydride and diphenoquinone. , Amorphous silicon, amorphous selenium, tellurium, selenium-tellurium alloy, cadmium sulfide,
Examples include inorganic materials such as antimony sulfide, zinc oxide, and zinc sulfide. The charge transporting material is not limited to those listed here, and can be used alone or as a mixture of two or more.

As the binder resin, it is preferable to use a high molecular polymer which is hydrophobic and can form an electrically insulating film. As such a high-molecular polymer, for example,
Polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acetic acid Vinyl-maleic anhydride copolymer, silicone resin, silicon-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polyvinyl butyral, polyvinyl formal, polysulfone, and the like. It is not limited. These binder resins are used alone or in combination of two or more. Further, additives such as a plasticizer, a sensitizer, and a surface modifier can be used together with these binder resins.

Examples of the plasticizer include biphenyl, biphenyl chloride, o-terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenylphosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin and the like.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B, cyanine dye, merocyanine dye, pyrylium dye, and thiapyrylium dye.

Examples of the surface modifier include silicone oil and fluororesin. In order to improve the adhesiveness between the cylindrical substrate 1 and the photosensitive layer or to prevent the injection of free charges from the cylindrical substrate 1 into the photosensitive layer, the distance between the cylindrical substrate 1 and the photosensitive layer may be changed as required. An adhesive layer or a barrier layer (undercoat layer) may be provided.

Materials used for these layers include, in addition to the polymer compound used for the binder, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, polyimide, carboxy-methyl cellulose, vinylidene chloride-based polymer latex, Polyurethane, aluminum oxide, tin oxide,
Titanium oxide and the like can be mentioned.

The substance imparting a function as an adhesive or a barrier is not limited to those listed here.
When used, they can be used alone or as a mixture of two or more.

When the adhesive layer or the barrier layer is provided, the thickness is preferably from 0.005 μm to 12 μm, and more preferably from 0.01 μm to 2 μm.

When the above-mentioned charge generating material and charge transporting material are dispersed and dissolved in a binder resin solution, the solvent for dissolving the binder resin does not dissolve the underlying layer, although it depends on the type of the binder resin. Consider choosing from among things.

Specific examples of the organic solvent include alcohols such as methanol, ethanol, n-propanol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, cyclohexanone, isophorone and acetylacetone; N, N-dimethylformamide; , N
Amides such as dimethylacetamide; ethers such as tetrahydrofuran, dioxane, methyl cellosolve, and diglyme; esters such as methyl acetate, ethyl acetate, and diethyl carbonate; sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane; methylene chloride, chloroform; Aliphatic halogenated hydrocarbons such as carbon tetrachloride and 1,1,2-trichloroethane; benzene, toluene, o-
Examples include aromatics such as xylene, p-xylene, m-xylene, monochlorobenzene, and dichlorobenzene, but are not limited thereto. These solvents are used alone or in combination of two or more.

[0073]

EXAMPLES Hereinafter, examples of the method and apparatus for applying paint to a cylindrical substrate and the method of manufacturing a photosensitive drum for electrophotography according to the present invention will be described more specifically. It is not limited to the range.

(Example 1) An applicator roll 2 made of carbon steel having a surface roughness of 3.2S, a length of 260 mm, and an outer diameter of 65 mm, and a metalling roll 3 of the same specification, which had been subjected to hard chromium plating as a surface treatment, and after coating. Applicator roll 2
A cylinder gripped by a gripping device 9 having a bearing connected to a rotary driving device and having a forward / reverse rotatable bearing, capable of controlling a separating speed within a moving distance until completely separating from the rotating drive device. The substrate 1 was arranged as shown in FIG. A cleaning doctor 4 made of resin was disposed on the metering roll 3 as shown in FIG. Cylindrical substrate 1
Is made of aluminum and has a length of 254 mm and an outer diameter of 30.
mm and a hollow structure with a wall thickness of 1 mm. For the purpose of obtaining a photosensitive drum for electrophotography, an undercoating paint was first applied to the cylindrical substrate 1.

The undercoat paint is prepared by dissolving 3.5 parts of soluble nylon ("CM-8000" manufactured by Toray Industries, Inc.) in a mixed solvent consisting of 57.9 parts of ethanol and 38.6 parts of benzyl alcohol. did.

Both ends of the cylindrical substrate 1 are gripped by a gripping device 9 having a bearing that is connected to a rotation driving device (not shown) and that can rotate forward and backward. The gripping device 9 can be moved close to and away from the applicator roll 2, and after coating, the liquid film of the paint formed between the cylindrical substrate 1 and the applicator roll 2 is broken so that the cylindrical substrate 1 Are mounted on a moving device (not shown) that controls a separating speed within a moving distance until completely separated from the applicator roll 2 and can set a separating direction. Cylindrical substrate 1
And the applicator roll 2 are initially separated,
At the time of coating, the moving device is set so that the gap width is 60 μm. The gap width between the applicator roll 2 and the metering roll 3 was set to 90 μm from the beginning.

The rotation directions of the cylindrical substrate 1 and the applicator roll 2 are the same, and the rotation directions of the applicator roll 2 and the metering roll 3 are also the same. The peripheral speed is
The cylindrical substrate was set to 20 m / min, the applicator roll was set to 20 m / min, and the metering roll was set to 2 m / min. .

After the applicator roll 2 and the metering roll 3 are rotated, the coating tank 5 containing the coating 5 for the undercoat layer is formed.
2 is lifted by a lifting device (not shown), so that the lower portion of the applicator roll 2 is immersed,
A coating film having a uniform film thickness was formed on the outer peripheral surface of.

Thereafter, the cylindrical substrate 1 was brought close to the applicator roll 2 while rotating until the gap width described above was reached. As a result, the coating material on the applicator roll 2 was transferred to the cylindrical substrate 1 and application was started. After maintaining the rotating state as it is for 12 seconds from the start of the transfer, a plane including the axis of the cylindrical substrate 1 and the axis of the applicator roll 2 is placed in a direction of 45 degrees with respect to the axis of the applicator roll 2. 0
It was separated at a speed of mm / s until the gap with the applicator roll 2 became 500 μm, and then moved to a detachable position at a speed of 20 mms.

The cylindrical substrate 1 on which the undercoat layer was applied was air-dried while rotating it for 3 minutes, and then dried at 120 ° C. for 5 minutes by a hot-air circulating dryer.

The film thickness after drying was measured by a spectral reflection interference film thickness meter (“TFM-120” manufactured by Oak Manufacturing Co., Ltd.) and found to be 0.9 μm. Here, the paint film thickness at the time of application calculated from the film thickness after drying in consideration of the non-volatile component concentration of the paint used being 3.5%.
The gap width between the cylindrical substrate 1 and the applicator roll 2 at the time of application is 60 μm with respect to this coating film thickness.
m becomes 2.3 times. In the present invention, whether or not the gap between the cylindrical substrate 1 and the application roll 2 is twice or more the thickness of the paint film 5 formed on the outer periphery of the cylindrical substrate 1 is determined as described above. The determination is made in consideration of the film thickness and the concentration of the nonvolatile component of the used paint.

(Example 2) The coating apparatus used in Example 1 was applied to the cylindrical substrate 1 in which the undercoat layer was applied to the outer peripheral surface in Example 1 (hereinafter referred to as an undercoat layer-coated cylindrical substrate 1). Was used to apply the charge generation layer.

The paint for the charge generating layer was prepared by mixing 0.8 part of α-type oxytitanium phthalocyanine and 0.8 part of butyral resin (“ESLEC BH-3” manufactured by Sekisui Chemical Co., Ltd.) with 49.25 parts of isopropyl alcohol and It was added to a mixed solvent consisting of 49.25 parts of cyclohexanone, and dispersed and mixed together with glass beads having an average particle size of 1.0 mm to prepare.

The undercoat layer-coated cylindrical substrate 1 to be coated is
As in the first embodiment, both ends are gripped by a gripping device 9 having a bearing that is connected to a rotation driving device (not shown) and that can rotate forward and backward. The gripping device 9 can approach and separate from the applicator roll 2, controls the separation speed within a moving distance until completely separated from the applicator roll 2 after application, and can set the direction of separation. Is mounted on a moving device (not shown).

The undercoat layer-coating cylindrical substrate 1 and the applicator roll 2 are initially separated from each other, but the moving device is set so that the gap width is 40 μm at the time of coating. The applicator roll 2 and the metering roll 3
Was set to 60 μm from the beginning.

The rotation directions of the undercoat layer-coated cylindrical substrate 1 and the applicator roll 2 are the same, and the rotation directions of the applicator roll 2 and the metering roll 3 are also the same. The peripheral speed of the undercoat layer-coated cylindrical substrate 1 was 11.2.
m / min, applicator roll 2 is 10.1 m / mi
n, the metering roll is 2 m / min.

After rotating the applicator roll 2 and the metering roll 3, the paint tank 52 containing the charge generating layer paint 5 is lifted by a lifting device (not shown), and the lower part of the applicator roll 2 is immersed. Then, a coating film having a uniform thickness was formed on the outer peripheral surface of the applicator roll 2.

Thereafter, the cylindrical substrate 1 coated with the undercoat layer was rotated and brought close to the applicator roll 2 until the gap width was reached. As a result, the coating material on the applicator roll 2 was transferred to the undercoat layer-coated cylindrical substrate 1 and coating was started. After maintaining the rotating state as it is for 10 seconds from the start of the transfer, the plane including the axis of the cylindrical base 1 and the axis of the applicator roll 2 is 1 mm / It was separated at a speed of s until the gap with the applicator roll 2 became 500 μm, and then moved to a detachable position at a speed of 20 mm / s.

The undercoat layer-coated cylindrical substrate 1 coated with the charge generating layer was air-dried while being rotated for 3 minutes, and then dried at 120 ° C. for 5 minutes using a hot-air circulation dryer.

The film thickness after drying was measured by a spectral reflection interference film thickness meter (“TFM-120” manufactured by Oak Manufacturing Co., Ltd.) and found to be 0.2 μm. Here, the paint film thickness at the time of application calculated from the film thickness after drying in consideration of the nonvolatile component concentration of the used paint being 1.6% is 1
The gap width between the cylindrical substrate 1 and the applicator roll 2 at the time of application is 40 μm with respect to this coating film thickness.
m becomes 3.2 times.

Example 3 A cylindrical substrate 1 having a charge generation layer coated on the outer peripheral surface thereof in Example 2 (hereinafter referred to as a charge generation layer coated cylindrical substrate 1) was prepared by using the coating apparatus shown in FIG. And a charge transport layer.

The coating material for the charge transport layer is composed of 20 parts of an arylamine compound represented by the chemical formula (1) and a polycarbonate resin ("Iupilon Z-20" manufactured by Mitsubishi Gas Chemical Company, Inc.).
0 ") was prepared by dissolving 25 parts in a mixed solvent consisting of 58 parts of cyclohexanone and 58 parts of xylene.

[0093]

Embedded image

As in the case of the first embodiment, both ends of the cylindrical substrate 1 coated with the charge generating layer, which is the object to be coated, are gripped by a gripping device 9 which is connected to a rotation driving device (not shown) and has bearings capable of rotating forward and reverse. ing. The gripping device 9 can approach and separate from the applicator roll 2, controls the separation speed within a moving distance until completely separated from the applicator roll 2 after application, and can set the direction of separation. Is mounted on a moving device (not shown).

The charge generating layer coating cylindrical substrate 1 and the applicator roll 2 are initially separated from each other, but the moving device is set so that the gap width is 200 μm at the time of coating. The gap width between the applicator roll 2 and the metering roll 3 was set to 330 μm from the beginning.

The rotation direction of the charge generating layer-coated cylindrical substrate 1, the applicator roll 2, and the metering roll 3 is the same direction, and the peripheral speed of rotation is 10.
2m / min, applicator roll 10.2m / m
in, the metering roll 3 is 2 m / min.

After rotating the applicator roll 2, the paint pan 52 containing the charge transport layer paint 5 is raised by a lifting device (not shown), so that the lower part of the applicator roll 2 is immersed. A coating film having a uniform film thickness was formed on the outer peripheral surface of.

Thereafter, the cylindrical body 1 coated with the charge generating layer was rotated and brought close to the applicator roll 2 until the gap width was reached. This allows applicator roll 2
The above coating material was transferred to the charge generating layer coated cylindrical substrate 1 and coating was started. After maintaining the rotating state for 10 seconds from the start of the transfer, the plane including the axis of the cylindrical substrate 1 and the axis of the applicator roll 2 is placed at 0 ° so as to be at 45 ° to the axis of the applicator roll 2. It was separated at a speed of 5 mm / s until the gap with the applicator roll 2 became 2000 μm, and then moved to a detachable position at a speed of 20 mm / s.

The charge generating layer-coated cylindrical substrate 1 coated with the charge transporting layer was air-dried while being rotated for 12 minutes, and then dried at 120 ° C. for 60 minutes by a hot-air circulation dryer.

The film thickness after drying was measured by a high-frequency eddy current film thickness meter (“LH-300C” manufactured by Kett Science Laboratory Co., Ltd.) and found to be 27.2 μm. Here, the paint film thickness at the time of paint calculated from the film thickness after drying in consideration of the non-volatile component concentration of the paint used being 28% is 97 μm. 200 μm gap width between cylindrical substrate 1 and applicator roll 2
m becomes 2.1 times. The thickness distribution in the axial direction is shown in FIG. 14 and the thickness distribution in the circumferential direction is shown in FIG.

Using the electrophotographic photosensitive drum obtained as described above, a printing test was performed one day after the production, and the image characteristics were good.

(Example 4) When applying the coating material for the charge generating layer used in Example 2 to the cylindrical substrate 1 coated with the undercoat layer obtained in Example 1, the cylindrical substrate coated with the undercoat layer at the time of application was used. Example 1 was carried out under the same conditions and operations as in Example 2 except that one end in the axial direction had a wider gap of 50 μm than the other end. The gap between the undercoat layer-coated cylindrical substrate 1 and the applicator roll 2 was set to 50 μm at one end with a wide gap at the time of application. This is to break the coating liquid film from one end in the axial direction of the undercoat layer-coated cylindrical substrate 1. Applicator roll 2 of cylindrical substrate 1 coated with undercoat layer
As the separation started, the coating liquid film started to break from the side where the 50 μm gap was set wide, and the break occurred at a uniform speed.

The undercoat layer-coated cylindrical substrate 1 coated with the charge generation layer was air-dried while rotating it for 3 minutes, and then dried at 120 ° C. for 5 minutes by a hot-air circulation dryer.

The film thickness after drying was measured with a spectral reflection interference film thickness meter (“TFM-120” manufactured by Oak Manufacturing Co., Ltd.).
m, and there was no color unevenness in appearance.

Example 5 In applying the charge transport layer coating material used in Example 3 to the charge generating layer coating cylindrical substrate 1 obtained in Example 2, the charge generating layer coated cylindrical substrate 1 was used.
And the applicator roll 2 are initially separated,
At the time of coating, the gap width was set to 70 μm, and the gap width between the applicator roll 2 and the metering roll 3 was set to 180 μm from the beginning, and the operation was performed under the same conditions and operation as in Example 3.

The charge-generating layer-coated cylindrical substrate 1 coated with the charge-transporting layer was air-dried while being rotated for 12 minutes, and then dried at 120 ° C. for 60 minutes by a hot-air circulation dryer.

The film thickness after drying was measured with a spectral reflection interference film thickness meter (“LH-300C” manufactured by Kett Science Laboratory Co., Ltd.) and found to be 27.8 μm. Here, the paint film thickness at the time of application calculated from the film thickness after drying in consideration of the non-volatile component concentration of the paint used being 28% is 99 μm. Gap width between cylindrical substrate 1 and applicator roll 2 70 μm
Is 0.7 times. The thickness distribution in the axial direction is shown in FIG. 14, and the thickness distribution in the circumferential direction is shown in FIG.

(Comparative Example 1) In applying the coating material for the charge generation layer used in Example 2 to the cylindrical substrate 1 coated with the undercoat layer obtained in Example 1, the coated cylindrical substrate coated with the undercoat layer was applied. The coating for the charge generation layer was applied under the same conditions and operations as in Example 2 except that the direction of separation 1 was perpendicular to the axis of the applicator roll 2 and the separation speed was 10 mm / s. After the application, drying was performed in the same manner as in Example 2.

When the film thickness after drying was measured with a spectral reflection interference film thickness meter (“TFM-120” manufactured by Oak Manufacturing Co., Ltd.), the average film thickness was 0.21 μm. There is a dark band, and the thickness of this part is 0.3
It was 5 μm.

(Comparative Example 2) In applying the charge transporting layer coating material used in Example 3 to the charge generating layer coating cylindrical substrate 1 obtained in Example 2, the applied charge generating layer coating cylindrical shape was applied. The charge transport layer was applied under the same conditions and operations as in Example 3 except that the separating direction of the substrate 1 was perpendicular to the axis of the applicator roll 2 and the separating speed was 20 mm / s.

The charge-generating layer-coated cylindrical substrate 1 coated with the charge transport layer was air-dried while being rotated for 12 minutes, and then dried at 120 ° C. for 60 minutes by a hot-air circulation dryer.

The film thickness after drying was measured with a high-frequency eddy current film thickness meter (“LH-300C” manufactured by Kett Science Laboratory Co., Ltd.) and found to be 28.1 μm. FIG. 14 shows the axial film thickness distribution, and FIG. 15 shows the circumferential film thickness distribution.
As shown.

FIGS. 14 and 15 show that the method and apparatus for applying paint to a cylindrical substrate and the method for manufacturing a photosensitive drum for electrophotography according to the present invention allow the coating of the cylindrical substrate 1 from the applicator roll 2 after application. It can be seen that by controlling the separating direction and the separating speed, the uniformity of the coating film thickness formed on the outer peripheral surface of the cylindrical substrate 1 is improved.

[0114]

According to the method and apparatus for coating paint on a cylindrical substrate and the method of manufacturing a photosensitive drum for electrophotography according to the present invention, the paint layer supplied to the coating roll is coated with the cylindrical substrate and the coating roll. The gap is set to be at least twice the thickness of the paint film formed on the outer periphery of the cylindrical substrate, and applying the paint to the outer peripheral surface of the cylindrical substrate while rotating the cylindrical substrate and the application roll in the same direction. When the cylindrical substrate and the coating roll are separated from each other, the separation speed between the cylindrical substrate and the coating roll is set to 5 mm / s or less and 0.1 mm / s or more, and the cylindrical substrate is removed from the cylindrical substrate. Prevents irregularities in the paint applied when the cylindrical substrate is separated by separating the substrate in the direction oblique to the axial direction or by separating the axis of the cylindrical substrate and the axis of the application roll in an inclined state. , Simple control of cylindrical substrate It is possible to form a uniform coating film on the peripheral. Therefore, an electrophotographic photosensitive drum having a photosensitive layer having a uniform coating film on the outer peripheral surface of the cylindrical substrate can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a method and an apparatus for applying a paint to a cylindrical substrate according to the present invention, and an apparatus for applying a paint to a cylindrical substrate in one embodiment of a method for manufacturing a photosensitive drum for electrophotography.

FIG. 2 is a side view showing an apparatus for applying a coating material to the cylindrical substrate of FIG.

FIG. 3 is a side view showing a paint measuring means (gap setting doctor) in the apparatus for applying paint to a cylindrical substrate in FIG. 1;

FIG. 4 is a side view showing a plate-shaped paint measuring means in the apparatus for applying paint to a cylindrical substrate in FIG. 1;

FIG. 5 is a side view showing another paint measuring means in the paint applying apparatus for applying a paint to the cylindrical substrate shown in FIG. 1;

FIG. 6 is a side view showing another paint measuring means in the paint applying apparatus for coating a cylindrical substrate in FIG. 1;

FIG. 7 is a side view showing a pickup roll in the apparatus for applying a coating material to the cylindrical substrate of FIG. 1;

FIG. 8 is a schematic diagram showing a case where a cylindrical substrate and an applicator roll are rotated in the same direction.

FIG. 9 is a schematic diagram showing a case where a cylindrical base and an applicator roll are rotated in opposite directions.

10 is a view showing a state in which the cylindrical base is separated at a low speed from the state of FIG. 12;

FIG. 11 is a diagram showing a state immediately after separation in FIG. 10;

FIG. 12 is a view showing a paint application state before separation in the same-direction rotation state of FIG. 8;

13 is a diagram showing a state in which the cylindrical base is separated from the state shown in FIG. 12 at a high speed.

FIG. 14 is a graph showing the axial thickness distribution of the electrophotographic photosensitive drum obtained in Example 3, Example 5, and Comparative Example 2.

FIG. 15 is a graph showing a circumferential film thickness distribution of the electrophotographic photosensitive drum obtained in Example 3, Example 5, and Comparative Example 2.

FIG. 16 is a schematic diagram showing a separating direction between a cylindrical base and an applicator roll.

FIG. 17 is a schematic diagram showing a separating direction and a separating state between a cylindrical base and an applicator roll.

FIG. 18 is a schematic diagram showing a separating direction between a cylindrical base and an applicator roll.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylindrical base material 2 ... Coating roll (applicator roll) 3 ... Paint measuring means (metering roll) 4 ... Cleaning doctor 5 ... Paint 6 ... Gap setting doctor 7 ... Pickup roll 8 ... Paint pool 9 ... Gripping means

Claims (13)

[Claims] In a method of applying a coating material supplied to an application roll to a cylindrical substrate, the coating material supplied to the application roll is rotated by rotating the cylindrical substrate and the application roll. While applying a coating material to the outer peripheral surface of the cylindrical substrate, when separating the cylindrical substrate and the application roll, the separation speed between the cylindrical substrate and the application roll is 5 mm /
s or less, a method for applying paint to a cylindrical substrate. 2. The method according to claim 1, wherein, when separating the cylindrical substrate and the application roll, a separation speed between the cylindrical substrate and the application roll is set to 0.1 mm / s or more. Method for applying paint to cylindrical substrate. 3. The method for applying a paint to a cylindrical substrate according to claim 1, wherein the coating is performed while rotating the cylindrical substrate and the application roll in the same direction. 4. The method according to claim 1, wherein the gap between the cylindrical substrate and the coating roll is set to be at least twice the thickness of a coating film formed on the outer periphery of the cylindrical substrate. A method of applying paint to a cylindrical substrate. 5. The method according to claim 1, wherein, when separating the cylindrical substrate and the application roll, the cylindrical substrate is separated in a direction oblique to an axial direction of the cylindrical substrate. The method for applying a paint to a cylindrical substrate according to any one of the above. 6. The method according to claim 1, wherein when separating the cylindrical substrate and the application roll, the axis of the cylindrical substrate and the axis of the application roll are separated in an inclined state. The method for applying a paint to a cylindrical substrate according to any one of the above. 7. A method of applying paint to a cylindrical substrate, wherein the paint supplied to an application roll is applied to a cylindrical substrate, wherein the coating layer supplied to the application roll is rotated by rotating the cylindrical substrate and the application roll. While applying a coating material to the outer peripheral surface of the cylindrical substrate, when the cylindrical substrate and the application roll are separated, the cylindrical substrate is separated in a direction oblique to the axial direction of the cylindrical substrate. A method for applying a paint to a cylindrical substrate, characterized by comprising: 8. A method of applying a coating material supplied to a coating roll to a cylindrical substrate, wherein the coating layer supplied to the coating roll is rotated by rotating the cylindrical substrate and the coating roll. While applying a paint to the outer peripheral surface of the cylindrical substrate, when separating the cylindrical substrate and the application roll, the axis of the cylindrical substrate and the axis of the application roll are separated in an inclined state. Coating method on a cylindrical substrate. 9. A rotatable coating roll for supplying a coating material and applying the coating to a cylindrical substrate; and a cylinder for gripping the cylindrical substrate so as to be able to rotate forward and backward, and when the cylindrical substrate and the coating roll are separated from each other, A coating device for coating a cylindrical substrate, comprising: a gripping device capable of adjusting a separation speed between a cylindrical substrate and an application roll to 5 mm / s or less. 10. The apparatus according to claim 1, wherein the holding device is capable of separating the cylindrical substrate in a direction oblique to the axial direction of the cylindrical substrate when separating the cylindrical substrate from the application roll. An apparatus for applying a paint to a cylindrical substrate according to claim 9. 11. The gripping device according to claim 9, wherein, when separating the cylindrical substrate and the application roll, the axis of the cylindrical substrate and the axis of the application roll can be separated in an inclined state.
Or a coating device for coating a cylindrical substrate according to item 10. 12. The coating roll according to claim 9, further comprising a paint metering means disposed close to the outer periphery of the coating roll for a predetermined distance to supply the coating roll with a uniform film thickness. For coating paint on cylindrical substrates. 13. An electrophotographic photosensitive drum, wherein an electrophotographic photosensitive drum base and an application roll are disposed in close proximity to each other, and the electrophotographic photosensitive coating supplied to the application roll is applied to the electrophotographic photosensitive drum base and then dried. In the method of manufacturing a photosensitive drum, a coating layer supplied to a coating roll with a uniform film thickness by a coating measuring means is rotated by rotating the coating drum and the electrophotographic photosensitive drum base in the same direction. An electrophotographic photoreceptor paint is applied on the outer peripheral surface of the substrate, and when the applied electrophotographic photoreceptor drum substrate is separated from the application roll, the separation speed between the electrophotographic photoreceptor drum substrate and the application roll is increased. A method for producing a photosensitive drum for electrophotography, wherein the speed is 5 mm / s or less.