JPH09314033A - Coating method of coating liquid and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a uniform coating film without movement of dispersion particles in such a device that a smoothening member is attached to the nozzle of a coating liquid supply tube to smoothen the coating liquid injected through the injection port by the smoothening member, by using a conductive material to form the contact surface of the smoothening member for the coating film and electrically grounding the conductive material. SOLUTION: When a coating liquid is applied on a body 1 such as an electro- photographic photoreceptor, a coating liquid supplied from a coating liquid supply mechanism is injected through an injection port 22 of a nozzle of a coating mechanism while the body 1 is rotated. The tip of the nozzle 18 is covered with a smoothening member 20 which slides on the coating film and smoothens the surface of the coating film. Therefore, when the coating liquid is applied on the body 1, the liquid is rubbed by the contact region between the smoothening member 20 and the body to spread and smoothen the liquid. The smoothening member 20 is abutted on the body 1 under elastic force so that the nozzle 18 does not inhibit movement of the smoothening member 29. It is preferable that nozzle consists of a flexible material such as a silicone rubber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating liquid application method and apparatus, and more particularly to a coating liquid application method and apparatus using a nozzle and a smoothing member.

[0002]

2. Description of the Related Art Conventionally, a nozzle coating method has been known as one of the methods for forming a coating film on the surface of a substrate having a cylindrical shape, a cylindrical shape, or a flat plate shape. The nozzle coating method is to support an object to be coated horizontally, and when applying to a cylindrical or cylindrical object to be coated, rotate the object to be coated and relatively move the nozzle in the axial direction. When applied to the object to be coated, the object to be coated and the nozzle are relatively moved in the XY directions, the coating liquid is supplied to the surface thereof, and a coating film is formed by utilizing the fluidity of the coating liquid. It is a coating method.

However, the smoothing of the coating film in the conventional nozzle coating method depends on the affinity between the coating liquid and the object to be coated and the fluidity of the coating liquid, and it is difficult to control with high accuracy. Further, a jet of air is sprayed onto a spirally applied liquid (see Japanese Patent Laid-Open No. 59-196781), or is jetted vigorously from a nozzle to utilize flight energy (see, for example, Japanese Patent Publication No. 5-67345). However, when a solvent type coating liquid is used, it is difficult to form a sufficiently smooth coating film because the drying speed of the coating liquid on the surface of the object to be coated is fast.

Further, a method has been proposed in which the coating liquid is rubbed and smoothed by a coating film surface forming member provided separately from the nozzle (see, for example, JP-A-50-90404), but the coating space is opened to release the liquid. It is difficult to prevent very small irregularities from remaining on the surface when applied to the object to be coated in the form of drops,
Even if they are continuously applied in the form of a string, it is not easy to stabilize and smooth them by the method of separately providing the blade.

The distance between the nozzle and the object to be coated is 50 to 1
When it is close to about 00μ, the discharged coating liquid can smoothly move to the object to be coated based on the relative movement of the nozzle and the object to be coated to obtain a relatively smooth coating film. However, if the distance is a little larger than the nozzle diameter, droplets are formed in the nozzle opening, and the application to the object to be coated becomes intermittent.
As described above, in this case, the unevenness is not eliminated even if the blade is rubbed to smooth the surface, and the surface becomes remarkably rough as compared with, for example, dip coating. Therefore, it is necessary to keep the distance between the coated object and the nozzle within a certain value without causing collision between them, and for this purpose, an autofocus mechanism is incorporated to raise or lower the nozzle position based on the measured value. Alternatively, an accurate transport system must be formed so that the distance variation of the object to be coated does not occur, and there is a problem that these are expensive.

In view of the above situation, the present inventor has found that
No. 101289, by providing a coating liquid guide member that reaches the surface of the coating object at the nozzle opening, the requirement for positional accuracy of the nozzle with respect to the coating object is relaxed, and continuous discharge of the coating liquid and smoothing of the coating film are achieved. A possible coating method was provided.
However, even when the above coating method is used, when the solvent of the coating liquid has a particularly low boiling point (100 ° C. or less), solvent evaporation cannot be avoided until the coating liquid reaches the surface of the object to be coated,
It was necessary to devise such as providing a dedicated solvent supply pipe in order to dilute the concentrated coating liquid.

Further, the present inventor has previously provided a smoothing member function at the end of the coating liquid conducting member so that continuous coating can be performed even if the accuracy of the distance between the nozzle opening and the object to be coated is poor. The present invention provides a coating method and apparatus that can obtain a uniform coating film by performing smoothing simultaneously with coating (Japanese Patent Application No. 7-4717).
2).

However, although these methods are effective coating methods when the coating liquid has conductivity, they are not sufficient when the coating liquid is non-conductive. That is, in the case of a non-conductive coating liquid in which the coating surface is rubbed with a smoothing member in order to smooth the flow charge during pumping or smoothing with a pump, frictional charging occurs, and in the case of a coating liquid in which pigments are dispersed. After leaving the smoothing member, the dispersant moves in the coating film resulting in color unevenness.Even in the case of a uniform coating liquid, when leaving the smoothing member, electrostatic force is applied to the edge of the coating film. There was a problem that unevenness occurred on the.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and enables smoothing immediately after supplying a coating liquid without being affected by a change in viscosity of the coating liquid. It is intended to provide a coating liquid coating method and apparatus capable of obtaining a uniform coating film without the movement of dispersed particles.

[0010]

According to the present invention, a smoothing member is provided at a nozzle portion of a coating liquid supply pipe, the smoothing member is elastically brought into contact with an object to be coated, and the liquid is discharged from a coating liquid discharge port. In a coating liquid application method for smoothing a coating liquid with a smoothing member, at least the coating film contact surface of the smoothing member is formed of a conductive material,
A coating liquid application method characterized by electrically grounding this, and a smoothing member is provided at the nozzle portion of the coating liquid supply pipe and the smoothing member is elastically abutted on the object to be coated,
In a coating liquid coating device for smoothing a coating liquid discharged from a nozzle portion with a smoothing member, at least a coating film contact surface of the smoothing member is formed of a conductive material and is electrically grounded. A coating liquid coating device is provided. The coating method and apparatus of the present invention can be suitably used particularly for coating an electrophotographic photoreceptor.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below, taking as an example the case of applying to a cylindrical or cylindrical object. In FIG.
FIG. 3 is an explanatory view showing the case of using the method for manufacturing an electrophotographic photosensitive member as an example of a coating apparatus for carrying out the coating method of the present invention. The coating apparatus shown in FIG. 1 supplies a coating liquid to the surface of an object to be coated while moving in the axial direction of the object to be coated and a drive mechanism for horizontally supporting and rotating a cylindrical or columnar object substrate. It is composed of a coating liquid supply mechanism.

The object to be coated 1 is not particularly limited, and in the case of a substrate of an electrophotographic photosensitive member, a glass tube, an aluminum cutting tube, an aluminum squeezing tube, a resin tube, a paper tube, or the like, or a base for these tubes. A coated or ground-treated tube or an electrophotographic photoconductor recycling tube is used. The drive mechanism includes support plates 2 and 2 with bearings which are vertically arranged on the left and right at predetermined intervals, rotary shafts 3 and 3 which are horizontally arranged via bearings provided on the upper portions of the support plates, respectively. It is composed of a gear 4 fixed to one of the rotating shafts, a gear drive motor 5, and a timing belt 6 for transmitting the rotation of the motor 5 to the gear 4.

The object to be coated 1 is rotated by providing a fitting hole for the rotary shaft 3 in the center of the object to be coated 1 or by using flanges 7 and 7 which are attached to both ends of the object to be coated 1 in advance. That is, in the case of a cylindrical shape, after attaching the flanges 7, 7 to both ends of the object to be coated 1, the object to be coated 1 is positioned between the rotating shafts 3 and 3 and one of the rotating shafts is moved forward to move the flange 7, The rotary shafts 3, 3 are fitted and fixed in the respective center holes of 7, and the gear driving motor 5 is driven to rotate the article 1 to be coated. The flanges 7, 7 are mounted so that the axes of the objects to be coated, which are determined by the respective center holes of the flanges, are aligned.

The coating liquid supply mechanism includes support plates 8 and 8 which are vertically arranged on the left and right at predetermined intervals, two guide rods 9 and 9 which are arranged between the support plates, and the support plates 8 and 8. 8 and between the guide rods 9 and 9, one end of which is a screw screw 10 protruding from the support plate 8 and a gear 11 fixed to the end thereof, a gear driving motor 12, and rotation of the motor 12. Which has a timing belt 13 for transmitting the power to the gear 11, a fitting hole for the guide rod 9 provided on each of the left and right sides thereof, and a ball screw bearing portion for fitting the screw screw 10 provided at the center of the fitting hole. Moving body 1 arranged between plates 8 and 8
4, a flexible coating liquid supply pipe 15 having one end fixed to the moving body 14 and a nozzle portion at its tip facing the surface of the object 1 to be horizontally arranged, the coating liquid supply The pipe 15 comprises a coating liquid container 16 arranged on the other end side, and a metering pump 17 arranged in the middle of the coating liquid supply pipe 15.

The coating liquid supplied from the coating liquid supply mechanism is discharged from the discharge port of the nozzle 18 in the coating mechanism. A smoothing member 20 that slides on the coating film to smooth the surface of the coating film is attached to the tip of the nozzle 18.

As shown in FIGS. 2 (a) and 2 (b), the smoothing member 20 has a coating liquid contact surface 20a on its front surface, and a small hole 21 penetrating to the front and rear surface is formed at the center thereof. The small hole 2
A nozzle 18 is inserted into and connected to the nozzle 1 from the back side, and a coating liquid discharge port 22 is formed on the front side coating liquid contact surface 20a side. The small hole 21 is provided in the central portion of the smoothing member 20, but its position does not need to be strictly in the center, and the position is selected according to the purpose. In particular, the upper and lower positions have a wide allowable range and can be provided at any position according to the conditions.

The smoothing member 20 is elastically brought into contact with the object to be coated 1 by elastic force. Therefore, it is necessary that the nozzle 18 does not restrain the movement of the smoothing member 20,
It is desirable that the nozzle 18 be formed of a soft and flexible material such as silicon rubber, or that the nozzle 18 be formed of a rigid member and connected by a flexible tubular body. Smoothing member 20
The material of is not particularly limited as long as it has resistance to the coating liquid, but an elastic material having flexibility is suitable, and a thin plate of rubber, plastic, or metal such as copper, aluminum, phosphor bronze, or stainless steel is used. You can
It is particularly desirable to use a structure having rubber elasticity in which a dent is formed when it is subjected to an extreme pressing force.

In order to obtain such a structure, it is possible to use a soft material such as ethylene / propylene rubber, fluorine rubber, Teflon rubber, silicon rubber, ethylene / vinyl acetate copolymer, and soft vinyl chloride. Alternatively, an elastic structure can be obtained by forming a closed-cell foam using a material having relatively rigidity such as low density polyethylene or ethylene / vinyl acetate. When a material having a high hardness such as phosphor bronze or polyester is used for the coating liquid contact surface 20a of the smoothing member 20, it is preferable to reduce the thickness of the rigid material and line it with an elastic material.

The shape of the smoothing member 20 may be a flat rectangular parallelepiped as shown in FIG. 2, but a thick pipe, a round bar or the like may be applied. These blades are elastically brought into contact with the object to be coated. The force pressing the surface of the smoothing member 20 to be coated is 1 to 40 gf / contact entire surface, preferably 5 to 2
It is preferable to select the force, elastic modulus, and shape so that 0 gf / contact surface is obtained.

A method of elastically contacting the smoothing member 20 with the object to be coated 1 can be achieved by forming the smoothing member 20 from a material having an appropriate elasticity. By supporting an elastic material such as a piano wire 25, it is possible to impart appropriate elasticity.

Discharge port 22 of nozzle 18 for discharging the coating liquid
Is 1 to 1 from the point where the object to be coated 1 and the smoothing member 20 are in contact with each other.
It is desirable to form a small hole 21 above 0 mm so that the nozzle end is almost on the blade surface. When the smoothing member 20 is made of a non-conductive material, at least the coating liquid contact surface 20a of the smoothing member 20 is made conductive.

As a method for making the smoothing member 20 conductive, a conductive powder such as carbon, metal powder or the like is kneaded to make the entire material conductive when a non-conductive synthetic resin or synthetic rubber is used. be able to. Further, the smoothing member 20 is formed without being made conductive, and then the coating liquid contact surface 20 is made of a conductive material.
It is also possible to form a and ground paths on the surface to make the surface conductive. As a method of making the surface conductive, vapor deposition of metal, application of a curable conductive coating material, lamination of a conductive sheet, film, sewing or the like can be adopted depending on each material.

The inner diameter of the nozzle 18 is selected depending on the liquid viscosity and the discharge flow rate, but it is preferably 0.3 to 3 mmφ. As a preferable example of the smoothing member 20, a polyethylene terephthalate (thickness: 75 μm) 23 obtained by machining foamed polyethylene (foaming ratio of about 25 times) into a flat rectangular parallelepiped as shown in FIG. Can be done by installing.

The aluminum vapor-deposited surface is the side that comes into contact with the coating liquid, and the aluminum vapor-deposited polyethylene terephthalate sheet extends beyond the required area and is used for grounding. Further, as shown in FIGS. 2A and 2B, a member for embedding two piano wires 25, 25 in a foamed polyethylene block to give elasticity to the whole and at the same time support the polyethylene block on a supporting member 26. Can also be used as

FIG. 3 shows conductive polyethylene foam (resistance value 1
This is an example of a blade using 50 kΩcm), and grounding in this case can be performed through the piano wire 25.
Further, as shown in FIG. 4, the coating liquid contact surface 20 of the smoothing member 20.
It is also possible to adopt a structure in which a nozzle is bonded to a. In the illustrated coating liquid supply mechanism, the moving body 14 is provided with only one coating liquid supply pipe 15, but it is also possible to provide a plurality of coating liquid supply pipes at predetermined intervals, and the metering pump 1
It is also possible to provide a single coating liquid supply pipe in which 7 is common and the tip portion has a branched structure.

The coating liquid supply pipe is provided with a header 19 and the flexible nozzle 18 can be directly attached to the header, or a rigid pipe is attached to the header and the flexible nozzle 18 is attached to the pipe. You can also The position of the ejection port 22 of the nozzle 18 may be right above the axis of the cylindrical or cylindrical object 1 to be coated, or may be horizontally displaced from the rotation axis of the object to be coated.

The coating method according to the present invention is performed as follows. That is, the drive mechanism is used to horizontally support and rotate the object to be coated 1, while the coating liquid supply mechanism is used to rotate the object to be coated 1.
The coating liquid is supplied to the surface of the in a spiral or ring shape.
The supplied coating liquid is rubbed on the object 1 to be coated and, at the same time, rubbed at the contact portion of the smoothing member 20 with the object to be spread, and the coating liquid is spread and smoothed. In particular, if the rotation speed, the liquid viscosity, the amount of coating liquid supplied, etc. are properly adjusted, the smoothed liquid is cured by the usual immobilization means to form a uniform film. Examples of the immobilization means include air-drying in the case of a solvent evaporation type coating liquid, heating suitable for the resin in the case of a coating liquid using a curable resin, and ultraviolet irradiation. In the case of a plate-shaped object to be coated, the object 1 to be coated and the smoothing member 20 move relative to each other, but it is preferable to incline the smoothing member 20 in the direction in which the object to be coated 1 separates from each other.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the embodiment, as the coating liquid supply mechanism, the coating liquid supply pipe 15 is provided on the discharge side of the metering pump 17.
And the other end of the tube was connected to the header 19. A flexible nozzle 18 was directly attached to the header.

(Embodiment 1) This embodiment is an example using the smoothing member shown in FIG. Aluminum cutting tube (outer diameter 30.0
mm, inner diameter of the stamped wax portion 28.5 mm, length 260 mm), a flange was attached, and an inner expansion collet chuck of the object rotating mechanism was inserted into the flange hole and gripped. Drive the gear motor of the object rotating mechanism to move the aluminum cutting tube 1 to 200
Rotated at rpm. Length 100 as the smoothing member 20
mm, width 15 mm, thickness 10 mm, using a foamed polyethylene with 75μ Alpet (aluminum-deposited polyester sheet) fixed with a cover string with the aluminum deposition surface as the outer surface and extended above the foamed polyethylene. Grounded through a pet. In it,
As the flexible nozzle 18, a polyethylene pipe having an inner diameter of 0.6 mm was inserted into a small hole penetrating from the tip of the smoothing member 20 to a position of 40 mm and passed through so that the discharge port 22 came to the front surface.

The header 19 was set so that, when the header was lowered, the discharge port side of the smoothing member 20 was in contact with the aluminum cutting pipe at a position of about 60 ° from the horizontal. On the other hand, oxytitanium phthalocyanine 1 represented by the following formula (A)
To 0 parts by weight,

[0031]

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(Wherein X represents a halogen atom and n represents a number from 0 to 1) 200 parts by weight of n-propanol was added, and the mixture was pulverized and dispersed by a sand grind mill for 10 hours, and then polyvinyl butyral. (Denka Butyral # -6000C manufactured by Denki Kagaku Kogyo Co., Ltd.) was mixed with 5 parts by weight of a 10% methanol solution to obtain a dispersion liquid for a charge generating layer of an electrophotographic photoreceptor. Using this dispersion, the gear pump was operated so that the wet film thickness was 20 μm. The smoothing member was moved in the axial direction so that the aluminum cutting tube had a pitch of 0.6 mm per revolution. The coating film after air drying showed a uniform color tone, and the coating film thickness was uniform as in the sample obtained by dip coating.

(Embodiment 2) This embodiment is an example using the smoothing member shown in FIG. Aluminum tube 1 as in Example 1
Was gripped in the same way and rotated. The electrically conductive foamed polyethylene had a width of 15 mm, a length of 100 mm, and a thickness of 10 mm, and two 0.6 mmφ piano wires were inserted almost to the tip, and the piano wire was fixed to the nozzle base by sandwiching the piano wire with a metal plate and grounding. . 40m from the bottom of the conductive foam polyethylene
A polyethylene tube having an inner diameter of 1.0 mm was penetrated at the position m, and the opening of the polyethylene tube was positioned on the surface of the conductive expanded polyethylene. On the other hand, 56 parts by weight of a hydrazone compound represented by the following formula (1),

[0034]

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Hydrazone compound 1 represented by the following formula (2)
4 parts by weight,

[0036]

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Cyano compound 1.5 represented by the following formula (3)
Parts by weight,

[0038]

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And 100 parts by weight of polycarbonate resin (Novarex 7030A, Mitsubishi Chemical Co., Ltd.) were added to 1,4
500 parts by weight of dioxane and 50 parts of tetrahydrofuran
A coating solution for an electrophotographic photoreceptor charge transport layer dissolved in 0 part by weight of a mixed solvent was obtained. This coating solution is applied to wet film thickness 1
It was discharged from a polyethylene pipe so as to have a diameter of 00 μm. The polyethylene pipe was moved in the axial direction of the aluminum pipe so as to have a pitch of 1.0 mm per revolution. The rotation speed of the aluminum tube was 300 rpm. After coating, it was dried at 125 ° C. for 30 minutes, and the surface roughness of the coating film was measured. Rmax = 0.3μ
m. The film thickness was in the range of 19.7 to 20.3 μm. The coating was repeated several times on the sample, but when the polyethylene pipe was dipped and kept in the solvent used for coating for a short time and then kept in the solvent vapor, there was almost no clogging or dirt.

Comparative Example 1 Coating was carried out under exactly the same conditions as in Example 1, except that Alpet was not attached to the foamed polyethylene block. The liquid surface leaving the blade was smooth and the color tone was uniform, but the pigment gradually moved until the coating film was fixed,
The light and shade unevenness has occurred.

Comparative Example 2 Coating was carried out under exactly the same conditions as in Example 2, except that non-conductive expanded polyethylene was used. The surface roughness after drying was Rmax = 1.0 μm, and the trace of spiral movement of the foamed polyethylene was clearly recognized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coating liquid application device of the present invention.

FIG. 2A is a side sectional view showing a coating liquid application portion,
(B) is a rear view.

FIG. 3 is a side sectional view showing another example of a coating liquid application portion.

FIG. 4 is a side sectional view showing still another example of a coating liquid application portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Object to be coated 3 Rotating shaft 4 Gear 5 Motor 7 Flange 8 Support plate 9 Guide rod 12 Gear drive motor 14 Moving body 18 Nozzle 20 Smoothing member 20a Coating liquid contact surface 22 Coating liquid discharge port 25 Piano wire 26 Supporting member

Claims (8)

[Claims] 1. A smoothing member is provided at a nozzle portion of a coating liquid supply pipe, the smoothing member is elastically brought into contact with an object to be coated, and the coating liquid discharged from a coating liquid discharge port is smoothed by the smoothing member. In the coating liquid application method for smoothing, at least the coating film contact surface of the smoothing member is formed of a conductive material, and this is electrically grounded. 2. The coating liquid application method according to claim 1, wherein the article to be coated is a columnar body or a cylindrical body that rotates about a central axis. 3. A smoothing member is provided in the nozzle portion of the coating liquid supply pipe, and the smoothing member is elastically brought into contact with an object to be coated so that the coating liquid discharged from the nozzle portion is smoothed by the smoothing member. In the coating liquid applying device, at least the coating film contact surface of the smoothing member is formed of a conductive material and is electrically grounded. 4. A small hole penetrating the front and back surfaces is bored in the central portion of the smoothing member, a nozzle portion of a coating liquid supply pipe is connected to the small hole, and a coating liquid discharge port is formed on the front surface of the smoothing member. The coating liquid coating apparatus according to claim 3, wherein the coating liquid discharging port of the smoothing member is elastically abutted on the object to be coated while being formed. 5. The coating liquid applying apparatus according to claim 3, wherein the smoothing member is formed of an elastic material to impart elasticity. 6. The coating liquid applying apparatus according to claim 3, wherein the smoothing member is supported by an elastic material to impart elasticity. 7. The coating liquid applying apparatus according to claim 3, wherein the smoothing member is made of a foam of a conductive resin. 8. The coating liquid application apparatus according to claim 3, wherein the smoothing member is made of a synthetic polymer material having a metal layer laminated on the coating liquid contact surface.