JP2004205916A - Coating method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when an electrophotographic photoreceptor is coated with an organic photosensitive material which is a coating liquid for a photosensitive layer by means of a spray nozzle, in the case where the electrophotographic photoreceptor is rotated, the coating liquid for a photosensitive layer is scattered by centrifugal force and a uniform coated surface is not obtained. <P>SOLUTION: After vertically holding a nearly cylindrical work of an electrophotographic photoreceptor, a spray nozzle for discharging a coating liquid for a photosensitive layer revolves on an axis of the nearly cylindrical work and coating is carried out while relatively moving the spray nozzle and the nearly cylindrical work in the axis direction of the nearly cylindrical work, whereby the problem that an organic photosensitive material which is the coating liquid for a photosensitive layer after coating is scattered by centrifugal force and a uniform coated surface is not obtained, can be solved, and this method is applicable also to a nearly cylindrical work which is composed of a polyester film or a metal sheet, has a large area and a large outside diameter, and comes into general use in recent years. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating apparatus and a coating method for manufacturing an electrophotographic photosensitive member by applying a coating solution for a photosensitive layer, particularly an organic photosensitive material, to a substantially cylindrical work made of a conductive film or a metal drum.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a dip coating method, a coating method using a slide hopper, and the like have been known as methods for manufacturing an electrophotographic photosensitive member by applying a coating solution for a photosensitive layer to an outer peripheral surface of a cylindrical work. However, in particular, in the dip coating method, the uniformity of the coating condition on the coating surface is good, but the film thickness is inevitably increased, and the end face is sealed so that the surplus coating liquid does not enter the conveying equipment or the inner surface. It remained on the sheath material and the like, and required an excessive amount of coating liquid.
[0003]
In the slide hopper system, it is difficult to keep the interval between the coating head and the target cylindrical work uniform in the circumferential direction, and to accurately align the axis of the cylindrical work with the axis of the coating head, especially Regulations on the positioning of cylindrical workpieces were eliminated. (For example, refer to Patent Document 1.)
In recent years, a cylindrical work serving as an electrophotographic photoreceptor is not limited to a cylindrical form made of glass or metal, but is generally made of a polyester film or a metal sheet. The electrophotographic photoreceptor as a cylindrical work made of the film or sheet is different from a cylindrical work made of glass or metal, and has a small thickness and poor cylindrical accuracy.
[0004]
In addition, at the same time as the cylindrical work composed of the film or the sheet becomes mainstream, the size of the cylindrical work, particularly the external shape of a circle, tends to increase. Therefore, the above-mentioned slide hopper type has limitations on cylindrical accuracy and diameter dimensions. In the present application, a cylindrical work as an electrophotographic photosensitive member having poor cylindrical accuracy is referred to as “substantially cylindrical work”.
[0005]
It is known that a spray nozzle system which is relatively flexible is becoming effective for the accuracy error of the distance from the substantially cylindrical work, and the spray nozzle system is suitable and advantageous in terms of efficiency. (For example, see Patent Document 2)
[Patent Document 1] Japanese Patent Application Laid-Open No. 1993-216252 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-278105 [Problems to be Solved by the Invention]
As described in the related art, a cylindrical work serving as an electrophotographic photosensitive member is not only in a cylindrical form made of glass or metal, but also made of a polyester film or a metal sheet. The electrophotographic photoreceptor as a substantially cylindrical work made of the film or sheet is different from a cylinder made of glass or metal and has a small thickness and poor cylindrical accuracy. The scheme is preferred. However, the conventional coating method or apparatus configuration is a method in which a substantially cylindrical work to be coated is rotated and a spray nozzle is relatively moved in the axial direction of the substantially cylindrical work.
[0006]
An organic photosensitive material, which is a coating solution for a photosensitive layer, is diluted with a volatile solvent, and has a property that, as soon as it is applied, the solvent volatilizes and drying starts. Therefore, when applying to the next application position adjacent to the previously applied position, if the adjacent portion is not applied before the previously applied organic photosensitive material is sufficiently dried, uneven coating occurs. Therefore, when applying an organic photosensitive material, which is a photosensitive layer coating liquid, to a substantially cylindrical work, it is preferable to apply spirally so that the drying times at adjacent application positions are always the same. However, when the diameter of the substantially cylindrical work to be applied increases, the substantially cylindrical work rotates once and is applied to an adjacent coating position if the circumferential speed of the substantially cylindrical work applied by the spray nozzle is the same. The drying time was too long, and there was a problem of uneven coating.
[0007]
The centrifugal force acts when the peripheral speed of the substantially cylindrical work is increased in order to shorten the time for one rotation so that the organic photosensitive material which is the coating solution for the photosensitive layer is not excessively dried. There has been a problem that an organic photosensitive material, which is a coating solution for a photosensitive layer, is scattered. In addition, if the number of spray nozzles is increased and multiple spray nozzles are provided, and if the organic photosensitive material, which is the coating solution for the photosensitive layer, does not proceed to dry, it will be applied to adjacent coating positions. Must be strictly matched with each other, however, it is extremely difficult to match them, and there is a problem that spots are eventually formed.
[0008]
Further, in the case of the spray nozzle method, there is a problem that the spray state (discharge amount, particle size, etc.) is not stable immediately after the start of spraying, and that application unevenness occurs when applied immediately after the start of spraying.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the coating method and the coating apparatus according to the first invention of the present invention include a spray nozzle that discharges a photosensitive coating solution after vertically holding a substantially cylindrical workpiece of an electrophotographic photosensitive member. It has a mechanism that has a drive means that rotates around the axis of the substantially cylindrical work and that can apply the spray nozzle and the substantially cylindrical work while relatively moving the spray nozzle and the substantially cylindrical work in the axial direction of the substantially cylindrical work. And According to this apparatus, although the substantially cylindrical work moves in the axial direction, it does not rotate, so the problem that the applied organic photosensitive material, which is the coating liquid for the photosensitive layer, is scattered by centrifugal force and a uniform coated surface cannot be obtained is solved. It is possible to cope with a substantially cylindrical work having a large area and a large outer diameter with at least one spray nozzle.
[0010]
Further, the coating method and the apparatus according to the second invention of the present invention are such that the spray nozzle rotates in the axial direction of the cylindrical work as the electrophotographic photosensitive member while rotating about the axis of the cylinder of the substantially cylindrical work. When applying the spray while relatively moving the spray nozzle and the substantially cylindrical work, start spraying at an external position from the axial end of the cylinder of the substantially cylindrical work, perform preliminary spraying, and apply after the spray from the spray nozzle is stabilized Is started. As a result, a stable discharge can be obtained from the spray nozzle at the start of coating, and the problem of uneven coating due to a difference in the discharge state can be solved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a coating method and an apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of the coating apparatus. In FIG. 1, a work support 3 is provided on an up-down drive unit 8 provided on a support 2, and the work support 3 is configured not only to move up and down by the up-down drive but also to pivot about the support 2 as a machine axis. . The work support 3 is configured such that a holder 21 for holding a substantially cylindrical work 20 is suspended from the tip of the work support 3. In order to position the photosensitive layer coating liquid 30 on the substantially cylindrical work 20, first, the vertical drive means 8 provided on the support 2 moves upward, and the work support 3 is turned around the support 2 as an axis. Then, the work support 3 and the holder 21 are lowered by the vertical drive means 8 at a position above the supply area of the substantially cylindrical work 20 (not shown), and stopped at a height capable of holding the substantially cylindrical work 20. The substantially cylindrical work 20 is held by operating the holder 21. Then, the spray nozzle support 15 is moved upward by using the vertical drive means 8 to move the spray nozzle support 15 upward to a height sufficient to prevent the lower portion of the substantially cylindrical workpiece 20 from interfering with the spray nozzle support 15. The work support 3 is swiveled using the up-down drive means 8 and is lowered using the up-down drive means 8 to a position at the center of the spray nozzle support 15 where the photosensitive layer coating liquid 30 is applied. To position.
[0012]
An outline of a mechanism for applying is described. In FIG. 1, a spray nozzle support 15 is rotatable, is connected to a drive shaft 5 and a belt 6 with a rotation shaft 7 provided on a loading platform 4 as a machine shaft, and is rotationally controlled by a control mechanism (not shown). . The photosensitive layer coating liquid 30 is rotatably connected to the spray nozzle support 15 from the liquid supply unit 12 through a hollow portion of the rotary shaft 7 formed in a tubular shape by a rotatably connected supply mechanism. Is supplied to the spray nozzle 10 through a supply pipe incorporated in the configuration of the spray nozzle support 15 through the supply mechanism.
[0013]
The excess of the photosensitive layer coating liquid 30 is collected by the liquid receiving unit 11 until the photosensitive layer coating liquid 30 sprayed from the spray nozzle 10 is jetted from the spray nozzle, as described below. The photosensitive layer coating liquid 30 is ejected and collected.
[0014]
A mechanism for collecting a surplus of the photosensitive layer coating liquid 30 will be described with reference to FIGS. 1, 2, and 3. FIG. As shown in FIG. 1, a liquid receiving unit 11 is provided above a holder 21 of a work support 3 via an arm 41, and a photosensitive layer coating liquid 30 sprayed from a spray nozzle 10 is applied to the liquid receiving unit 11. It is designed to be collected.
[0015]
As shown in FIG. 2, a liquid receiving unit rotating mechanism 40 is provided above the position of the spray nozzle 10 of the spray nozzle support 15, and an arm 41 is attached to the tip of the liquid receiving unit rotating mechanism 40 that receives the spray of the spray nozzle 10. The liquid receiving unit 11 is provided through the liquid supply unit, and the liquid receiving unit rotating mechanism 40 is operated, so that the coating liquid 30 for the photosensitive layer sprayed from the spray nozzle 10 can be freely sprayed and shielded by the liquid receiving unit 11. It is possible. In addition, as shown in FIG. 3, the liquid receiving portion 11 is fixed via the arm 41 in a circumferentially outward direction of the frame of the spray nozzle support 15. In the step of providing the spray nozzle rotating mechanism 45 at the installation position of the spray nozzle 10 of the spray nozzle support 15 and applying the photosensitive layer coating liquid 30 to the substantially cylindrical work 20, the spray nozzle 10 is attached to the substantially cylindrical work 20. Until the spraying from the spray nozzle for application is stabilized, the spray is positioned and sprayed in the direction of the liquid receiving unit 11 via the spray nozzle rotating mechanism 45 as preliminary spraying. The photosensitive layer coating liquid 30 sprayed to the liquid receiving section 11 is received and collected. As a mechanism for collecting the photosensitive layer coating liquid 30, in the case of FIG. 1, the liquid is collected by the liquid collecting section 13 from the liquid receiving section 11 through the work support 3 vertical driving means 8 support column 2. 2 and 3, the supply of the coating solution 30 for the photosensitive layer from the liquid supply unit 12 to the spray nozzle 10 is reversed, and the liquid reception unit 11 supplies the spray nozzle support 15 through the internal pipe of the rotating shaft 7. The process returns to the liquid recovery unit 13. Actually, the photosensitive layer coating liquid 30 injected into the liquid receiving section 11 does not return to the liquid collecting section 13 naturally. Therefore, the liquid collecting section 13 is provided with a suction mechanism (not shown).
[0016]
The above-described coating liquid 30 for the photosensitive layer sprayed from the spray nozzle 10 is prevented from scattering and being coated on the coating surface of the substantially cylindrical workpiece 20 before coating, and the excess coating liquid 30 for the photosensitive layer is collected. Needless to say, if the requirement to perform is satisfied, the mechanism relating to the liquid receiving portion is not necessarily illustrated.
[0017]
A coating process using the coating device 1 of the above mechanism will be described. As described above, the substantially cylindrical workpiece 20 is placed at a predetermined position by the holder 21, and the liquid receiving section 11 shown in FIG. 1, FIG. 2 or FIG. I will The liquid supply unit 12 is activated, and the photosensitive layer coating liquid 30 is sent to the spray nozzle 10 through the rotary shaft 7 spray nozzle support 15. The coating liquid 30 for the photosensitive layer is ejected from the spray nozzle 10 toward the liquid receiving section 11 by preliminary ejection. By jetting for a certain period of time, air in the path from the liquid supply unit 13 to the spray nozzle 10 disappears, and the air is stabilized.
[0018]
Simultaneously with the start of spraying from the spray nozzle 10 or after the spraying is stabilized, the rotation of the spray nozzle support 15 is increased until a predetermined rotational speed is reached. At the stage when the number of rotations of the spray nozzle support reaches the set number of revolutions, the liquid receiving unit 11 which has been receiving the injection of the photosensitive layer coating liquid 30 from the spray nozzle 10 is moved by using the mechanism shown in FIG. 1, FIG. 2 or FIG. Release from spray nozzle 10. While the coating liquid 30 for the photosensitive layer is stably sprayed through the spray nozzle 10, the substantially cylindrical workpiece 20 held by the holder 21 is raised at an appropriate speed by the vertical driving means 8 via the workpiece support 3. Let it. As a result, the substantially cylindrical work 20 and the spray nozzle 10 located on the spray nozzle support 15 move in the cylindrical axis direction of the substantially cylindrical work 20, and the substantially cylindrical work 20 is sprayed. The periphery of the work 20 can be spirally applied.
[0019]
Here, as shown in FIG. 1, a mechanism is shown in which the substantially cylindrical work 20 moves up and down by the vertical driving means 8 with respect to the relative movement of the substantially cylindrical work 20 and the spray nozzle 10 in the axial direction of the substantially cylindrical work 20. However, the relative movement may be a mechanism in which the spray nozzle 10 moves up and down, or both may move.
[0020]
Spiral application is continued, the relative movement progresses, the lower end in the axial direction of the substantially cylindrical work 20 passes, and when the application of the photosensitive layer coating liquid 30 to the substantially cylindrical work 20 is completed, spraying is performed. In the case of the mechanism shown in FIG. 2, the liquid receiving unit 11 moves via the liquid receiving unit rotating mechanism 40 and the arm 41 in order to interrupt the photosensitive layer coating liquid 30 which has been continuously ejected from the nozzle 10. In this case, the spray nozzle 10 rotates via the spray nozzle rotating mechanism 45. In the case of the mechanism of FIG. 1, the supply from the liquid supply unit 12 is immediately stopped.
[0021]
Thereafter, the substantially cylindrical work 20 held by the holder 21 and the work support 3 is rotated about the support column 2 via the vertical drive means 8 until the support 20 is positioned at the receiving position of the substantially cylindrical work 20 (not shown). The driving means 8 descends and transfers the substantially cylindrical workpiece 20 on which the application of the photosensitive layer coating liquid 30 has been completed to the receiving section.
[0022]
Once again, the next substantially cylindrical work 20 is held by the holder 21 so that the coating liquid 30 for the photosensitive layer is continuously applied to the substantially cylindrical work 20.
[0023]
As described above, by using the coating apparatus 1, the steps from receiving the substantially cylindrical work 20, applying the photosensitive layer coating liquid 30 to the delivery, and passing the work without touching the substantially cylindrical work 20 are performed. Damage and adhesion of dirt can be prevented.
[0024]
【Example】
Hereinafter, an example in which the coating liquid for a photosensitive layer is actually applied to a substantially cylindrical workpiece using the coating apparatus 1 of the present invention will be described, but the present invention is not limited to the example.
(Example 1)
As the photosensitive layer coating solution, a solution prepared by diluting a photosensitive layer coating solution corresponding to a conventional immersion method with a solvent was used. As a substantially cylindrical workpiece actually coated with the photosensitive layer coating liquid, a workpiece having a diameter of 470 mm and a length of 600 mm in the axial direction was used. Application was performed at a discharge rate of 5 ml / min or less, a rotation speed of 200 rpm or less, and an axial relative movement speed of 10 mm / sec or less.
(Comparative Example 1)
The movement of the spray nozzle is set only in the axial direction of the substantially cylindrical work so that the mutual application condition between the spray nozzle and the substantially cylindrical work is the same as that in the first embodiment, and the substantially cylindrical work is rotated to rotate the photosensitive layer. When the application liquid for application was applied, a decrease in the amount of application due to centrifugal force was observed, the applied film thickness became thinner, and coating unevenness occurred.
(Comparative Example 2)
In Comparative Example 1, the movement of the spray nozzle is set only in the axial direction of the substantially cylindrical work, and the substantially cylindrical work is rotated so that the mutual application conditions of the spray nozzle and the substantially cylindrical work are the same as those in Example 1. By applying the coating solution for a photosensitive layer in this manner, the coating amount was reduced due to centrifugal force, and the coating film thickness was reduced and coating unevenness occurred. Accordingly, the movement of the spray nozzle was set only in the axial direction of the substantially cylindrical work, and the rotation speed of the substantially cylindrical work was set to の of that in Comparative Example 1 to apply the photosensitive layer coating solution. Although the result was improved as compared with Comparative Example 1, coating unevenness occurred due to a difference in drying time.
[0025]
【The invention's effect】
After holding the substantially cylindrical work of the electrophotographic photoreceptor vertically, the spray nozzle for discharging the photosensitive coating liquid rotates about the axis of the substantially cylindrical work, and the spray nozzle and the substantially cylindrical work are rotated in the rotation axis direction. Is applied while relatively moving in the axial direction of the substantially cylindrical work, the problem that the applied organic photosensitive material as the coating solution for the photosensitive layer is scattered by centrifugal force and a uniform coating surface cannot be obtained can be solved. It is also applicable to large-area, large-diameter substantially cylindrical workpieces made of polyester films and metal sheets, which have become popular in recent years.
[0026]
Although the substantially cylindrical work made of the polyester film or the metal sheet has poor cylindricity, the use of the spray nozzle coating method has a slight error in the distance between the spray nozzle and the surface of the substantially cylindrical work. However, the influence on the finish quality of coating is small.
[0027]
In spraying, the spray nozzle rotates in the axial direction of the cylindrical work as the electrophotographic photosensitive member around the axis of the cylinder of the substantially cylindrical work, and moves while relatively moving the spray nozzle and the substantially cylindrical work in the rotation axis direction. Injection starts at an external position from the axial end of the cylinder of the substantially cylindrical work, preliminary injection from the spray nozzle is performed, and application is started after the injection is stabilized, so that stable discharge can be obtained at the start of coating. Thus, it is possible to eliminate the occurrence of spots due to the difference in the ejection state.
[Brief description of the drawings]
FIG. 1 is a schematic view of a coating apparatus according to an embodiment of the present invention, showing a first example of a mechanism relating to a liquid receiving unit.
FIG. 2 is a diagram showing a second example of a mechanism relating to a liquid receiving unit in FIG. 1;
FIG. 3 is a view showing a third example of a mechanism relating to a liquid receiving unit in FIG. 1;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 coating device 2 support 3 work support 4 carrier 5 drive shaft 6 belt 7 rotation shaft 8 vertical drive means 10 spray nozzle 11 liquid receiving unit 12 liquid supply unit 13 liquid recovery unit 20 substantially cylindrical work 21 holder 30 for photosensitive layer Coating liquid 40 Liquid receiving unit rotating mechanism 41 Arm 45 Spray nozzle rotating mechanism

Claims (4)

In an electrophotographic photoreceptor manufacturing apparatus for applying a photosensitive layer coating solution to a substantially cylindrical work by spraying, the substantially cylindrical work is vertically supported, and a spray nozzle is arranged around the substantially cylindrical work. A coating apparatus, comprising: a circulating means for circling the outer periphery of a substantially cylindrical work; and a driving means for relatively moving the substantially cylindrical work and a spray nozzle in the axial direction of the substantially cylindrical work. A liquid receiving part for receiving the photosensitive layer coating liquid sprayed from the spray nozzle when starting to spray the photosensitive layer coating liquid from the spray nozzle at a position outside the end of the substantially cylindrical workpiece. 2. The coating device according to 1. In a method of manufacturing an electrophotographic photoreceptor in which a coating solution for a photosensitive layer is applied to a substantially cylindrical work by spraying, a spray nozzle is disposed so as to vertically support the substantially cylindrical work and orbit around the substantially cylindrical work. After moving the substantially cylindrical work and the spray nozzle relative to each other in the axial direction of the substantially cylindrical work, and starting spraying the photosensitive layer coating liquid from the spray nozzle at a position outside the end of the substantially cylindrical work, the spray nozzle is substantially cylindrically moved. A coating method for applying a coating solution for a photosensitive layer while moving a substantially cylindrical work and a spray nozzle relative to each other in the axial direction of the substantially cylindrical work while orbiting the outer periphery of the work. 4. The photosensitive layer coating solution sprayed from the spray nozzle is received by a bearing portion when the spraying of the photosensitive layer coating solution from the spray nozzle is started at a position outside the end of the substantially cylindrical workpiece. Application method.

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