JPS6061756A - Apparatus for producing electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain efficiently the coated film of a photosensitive material having good quality by supplying a coating after dispersion through a filter to a coating tank prior to generation of drying, etc. on the surface of the coating, passing the paint overflowing from the upper part of the coating tank again throuth the filter and supplying cyclically the coating to the coating tank. CONSTITUTION:A sand mill device for dispersing a pigment, a filter for filtration of a coating and a dip coating tank are provided in order to form an electrophotographic sensitive body on a base body by a dip coating method. The paint after the dispersion is passed through a filter and is supplied to the coating tank prior to drying of the coating surface, reflocculation of the pigment, increase in viscosity and gelation. The coating overflowing from the upper part of the coating tank is again passed through the filter and is supplied cyclically to the coating tank. More specifically, the coating 46 fed continuously to the coating tank 44 overflows from the upper part of the tank 44 and is gathered in a receiving tray 45, from which the coating is again returned to a coating tank 40 and is supplied to the tank 44. The base body 30 of an electrophotographic sensitive body is attached to a lifting member 32 and is vertically moved by the rotation of a screw 33. The supply of the coating after dispersion through a filter 17 to the tank 44 and the supply of the overflowing coating again to the tank 44 are thus made possible and the good coated film of the photosensitive material is efficiently obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing an electrophotographic photoreceptor by coating a photosensitive material coating onto a substrate, and in particular to an apparatus for manufacturing an electrophotographic photoreceptor by coating a photosensitive material coating on a substrate, and in particular, for efficiently coating a dispersed photosensitive material coating in which a pigment is dispersed in a resin solution. The present invention relates to an apparatus for manufacturing an electrophotographic photoreceptor, which can produce a photosensitive material coating film with good properties.

An electrophotographic photoreceptor basically has a structure in which a photosensitive layer is formed on a conductive substrate. The photosensitive layer is generally one in which selenium is vapor-deposited, but the manufacturing cost is high and the productivity is low. As a method for forming a photosensitive layer, a method of applying a photosensitive material coating onto a substrate is very advantageous in terms of cost, productivity, yield, and applicability to a wide variety of substrate shapes.

As a photosensitive layer produced by coating, one in which dye-sensitized powder of zinc oxide or cadmium sulfide is dispersed in a binder resin is known. These use inorganic photosensitive materials, but organic photosensitive materials include polyvinylcarbazole, trinitrofluorene, phthalocyanine,
It is known that pyrazoline oxadiazole or the like is mixed or dispersed with a binder as necessary. In addition, functionally separated photosensitive layers in which a charge generation layer and a charge transport layer are stacked are also known in order to increase sensitivity, improve repeatability, and improve durability. The charge generation layer may include azo pigments such as Sudan Red, Diane Blue, and Jenas Green B, quinone pigments such as Algol Yellow, Pyrene Quinone, and Indanthrene Brilliant Violet RRP, indigo pigments such as quinocyanine pigments, perylene pigments, indigo, and thioindigo, and Indian Charge-generating substances such as bisbenzimidazole pigments such as Fast Orange toner, phthalocyanine pigments such as copper phthalocyanine pigments, and quinacridine pigments, polyester, polystyrene, polyvinyl butyral, polyvinyl pyrrolidone, methyl cellulose,
It is formed by being dispersed in a binder resin such as polyacrylic esters or cellulose esters. Its thickness is 0.0
The thickness is about 1 to 1μ, preferably about 0.05 to 05μ. In addition, the charge transport layer contains polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, coronene, etc. in the main button or side chain.
or indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole,
It is formed by dissolving a compound having a nitrogen-containing cyclic compound such as oxadiazole, pyrazoline, thiadiazole, and triazole, or a hole-transporting substance such as a hydrazone compound in a resin with a gold-forming property. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself.

Such resins include polycarbanates, premethacrylates, polyarylates, polystyrene,
polyester, polysulfone, steel (7-7)
Examples include ronitrile copolymer, styrene-methyl methacrylate copolymer, and the like.

The thickness of the charge transport layer is 5 to 20 microns.

In addition, conductive substrates used in the present invention include aluminum, yellow field, stainless steel, etc. formed into cylinders or foils, paper, plastic, etc., on which aluminum, tin oxide, antimony oxide, indium oxide, etc. are vapor-deposited. Or a laminated one is used. In addition, methods for forming the conductive layer include metal powders such as aluminum, silver, gold, nickel, and copper, carbon powders, tin oxide, antimony oxide,
There is also a method of applying a conductive paint in which a conductive coating material such as indium oxide is dispersed in a resin.

The electrophotographic photoreceptor manufactured by coating has been described above, and there are various coating methods such as spraying, roll coating, barcode coating, knife coating, screen coating, and dipping. Among these coating methods, the dip coating method is extremely advantageous for seamlessly coating a cylindrical substrate such as an electrophotographic photoreceptor by dipping the substrate into the coating and pulling it up. .

In such a dip coating method, in the case of a dispersed photosensitive material paint in which the pigment is completely dispersed in a solution, the specific gravity of the pigment is generally large, so that the pigment tends to settle or accumulate in the paint. As a result, uneven concentration and composition of the paint occur.
The paint film tends to become uneven. As a countermeasure against this, it is desirable to put the photosensitive material paint in which the pigment has been dispersed into the coating tank for dipping as soon as possible. Furthermore, it is preferable to keep the paint in constant motion so that the pigments do not settle.

There are various methods for dispersing pigments, such as ball mills, roll mills, sand mills, attritor mills, and colloid mills. The sand mill method is very advantageous in this respect. Since the sand mill method has a length D that allows the pigment to be continuously dispersed from rough dispersion to finish, it is disadvantageous from the standpoint of sedimentation to store the paint after dispersion in a container. It is also time-consuming and causes an increase in the number of steps.

The first feature of the present invention is that the sand mill device and the coating tank for dip coating are integrally connected, and the process from inputting raw materials to coating is performed continuously. According to the present invention, if the pigment and the resin solution used as a binder are put into the sand mill device when the paint is needed, the dispersed paint is sent to the coating tank, so the steps in between can be omitted and sedimentation can be avoided. It can be less.

Particularly when manufacturing an electrophotographic photoreceptor by coating, it is desirable to automate the process in order to prevent dust and dirt from forming in the coating film, and the present invention is highly effective.

An example of a sand mill apparatus for dispersing pigments is shown in FIG. Inside the container (vessel) 1, alumina,
It is filled with small particles made of materials such as zirconia, stainless steel, glass, sand, and iron. Paint raw materials are supplied from the input port 2. A plurality of blades 3 attached to a rotating shaft 4 are provided inside the container, and the blades 3 rotate at high speed to remove the pigment and resin solution inside the container.

The rotation speed is 200-4000 rpm. After being dispersed, the paint is separated from the dispersion medium through the entire mesh or grid 5, and comes out from the outlet 6. Such a sand mill device may be used alone, or if dispersion is insufficient, a plurality of sand mill devices may be connected to each other.

Although the paint that comes out of the sand mill passes through the gap, it contains crushed dispersion medium and undispersed coarse particles, and the paint that comes out of the sand mill contains a highly smooth surface like an electrophotographic photoreceptor. Difficult to use when a painted surface is required. Therefore, the second feature of the present invention is that a filter for filtering paint after sand milling is integrally connected to the sand mill apparatus.

The filter may have a mesh that does not allow passage of particles coarser than the thickness of the film to be coated, but preferably the mesh is finer than the film thickness and larger than the pigment particles. Also, it is more effective to reduce clogging by arranging in series a filter with large openings to capture coarse particles and a filter with fine openings to capture fine particles that cause dirt. .

The paint that has passed through the filter is sent to the coating tank.

The third feature of the present invention is that in order to agitate the paint in the coating tank and to keep the paint surfaces always fresh, the paint is constantly overflowing from the top of the coating tank, and the overflowing paint is recycled again. It passes through a filter and is circulated and supplied to the coating tank.

A pump is connected to circulate the liquid in this way and to supply the sand mill equipment with the paint before dispersion.

Magneticun J as a pump? Any pump, gear pump, dia slam pump, screw pump, etc. may be used.

That is, the electrophotographic photoreceptor manufacturing apparatus according to the present invention includes:
An apparatus for manufacturing an electrophotographic photoreceptor by coating a photosensitive material paint in which a pigment is dispersed onto a substrate by a dip coating method includes a sand mill device for dispersing the pigment, a filter for filtering the dispersed paint, and a device for applying the paint to the substrate. A coating tank for dip coating is installed continuously on top of the coating tank, and the dispersed paint is passed through a filter before the paint surface dries, pigment reagglomerates, viscosity increases, or gluing occurs. Then, the coating material is supplied to a coating tank, and the paint overflowing from the upper part of the coating tank is passed through the filter again to be circulated and supplied to the coating tank.

An embodiment of the apparatus of the present invention will be described below with reference to FIG.

The paint 1 before being dispersed is placed in a front tank 12, to which a stirrer 13 is attached.

The paint is pumped by a pump 14 to a sand mill device 15
sent to. In the illustrated embodiment, a two-barreled sand mill apparatus is shown, each having a structure as shown in FIG. The paint 41 after dispersion is stored in the paint tank 40,
Next, it is pressurized by the bomb f43, passes through the filter 172, and is sent to the coating tank 44. 18171 valve is shown.

The paint 46 continuously sent to the coating tank overflows from the top of the coating tank (71-perflow), is collected in a tray 45, is returned to the paint TI'v40, and is passed through the filter 1 again.
7 and are circulated and supplied to the coating tank.

The coating tank has a lid 47 to reduce evaporation of the solvent during overflow.

The base body 30 of the electrophotographic photoreceptor is attached to an elevating member 32 by a holding member 31, and this is moved up and down by the rotation of an elevating motor 34 and a screw 330.

As described above, the electrophotographic photoreceptor manufacturing apparatus according to the present invention includes a sand mill device 15 for dispersing pigment, a filter 17 for filtering the dispersed paint, and a coating tank for dip-coating the paint onto the substrate. 44, and the dispersed paint is supplied to the coating tank 44 through the filter 17 before the paint surface dries, pigment reagglomerates, viscosity increases, or gluing occurs. and coating tank 4
The paint overflowing from the upper part of the coating tank 4 passes through the filter 17 again and is circulated and supplied to the coating tank 44.

As described above, the electrophotographic photoreceptor manufacturing apparatus according to the present invention, in which the sand mill dispersion device, the filter, and the coating tank are all connected, can shorten the process and prevent pigment sedimentation when coating a pigment dispersion type paint. It is very effective in preventing reagglomeration and reducing solvent evaporation. It is also possible to prevent accidents such as paint stains and scattering during the process.

Furthermore, the device of the invention is very effective, especially when the dispersion coating is thixotropic.

If the paint is thixotropic, the viscosity of the paint will vary depending on the fluidity of the paint, and when the paint is allowed to stand still, the viscosity will gradually increase, and eventually it will become glued and lose its fluidity. One way to prevent this is to constantly stir the paint or apply dynamic stimulation from the outside, but it is time-consuming to remove the paint from the disperser once it has been dispersed. However, when the paint is continuously fed without being taken out to the outside as in the present invention, there is no need to worry about this.

Furthermore, since the paint overflows from the top of the coating tank and the overflowing liquid is passed through the filter again and supplied to the coating tank, it also has the effect of removing particles that have aggregated or settled in the coating tank.

In addition, in the apparatus of the present invention, it is not necessary to always disperse the paint, and it is only necessary to compensate for the amount reduced by coating. Each time, the worker confirms that the paint has decreased.
Although it is possible to operate the entire mill dispersion machine, it is preferable to
It's better if it's automated. For that purpose, paint tank 40
A mechanism for detecting the amount can be installed, and when the amount decreases below a certain level, the dispersed paint is supplied, and when the amount is filled, the dispersion is stopped. Mechanisms for detecting paint build-up include a method using a float roller, a method of optically detecting the liquid level, and the like.

Hereinafter, an example in which an electrophotographic photoreceptor was manufactured using the electrophotographic photoreceptor manufacturing apparatus shown in FIG. 2 will be described.

Example] shows the steps of forming an undercoat layer on the substrate of an electrophotographic photoreceptor using the apparatus shown in FIG. 2 shows the step of forming a photosensitive layer on the .

Example 1 In an apparatus for manufacturing an electrophotographic photoreceptor as shown in FIG. 2, the internal volume of the sand mill device 15 was set to 2.81 mm. The interior is shown in Figure 1, and the blades used were made up of eight blades. The space was filled with glass beads (manufactured by Toshiba Glass) having an average diameter of 1 φ. The rotation speed of the blade was 2000 rpm. The number of stages in the mill is 2 as shown in Figure 2, and 4? A dia slam pump with a capacity of 100 ml per minute was used for '14. The capacity of the front tank 12 was 51, and a homogenizer (manufactured by Yamato Kagaku) was attached to this to enable pre-dispersion.

The capacity of the paint tank 40 was 51, and a rotary agitator (manufactured by Shinsha Kagaku) was attached to it. , jC7 nno 43 is flow fjk1
1/min diaphragm pump. The filter 17 was a 25μ filter (manufactured by Toyoji Paper Co., Ltd., trade name Tonal TCW-25R8) attached to the housing. The coating tank 44 was cylindrical with an inner diameter of 80 mm and a height of 350 mm, and the upper part had a To catch the overflowing paint, a tray 45 was attached to the receiver, and piping was connected so that the paint returned from there to the paint tank 4°.

The base 3o of the electrophotographic photoreceptor has an outer diameter of 60'mm and a height of 26mm.
A cylindrical aluminum tube with a closed upper part and an open lower part was used. It is raised and lowered by a variable speed motor (Fuji Electric Ps motor).

The coating material was dispersed and applied using an electrophotographic photoreceptor manufacturing apparatus in which a sand mill device, a filter, and a coating tank were integrated as described above. First, a conductive smooth layer as shown in Japanese Patent Application No. 57-195062 was formed. Titanium oxide powder (manufactured by Sakai Chemical Co., Ltd.) 10 parts (parts by weight, the same applies hereinafter), tin oxide powder (manufactured by Mitsubishi Metals) 5 parts, -liquid epoxy resin (solid content concentration 50 t, manufactured by Amicon) 15 parts, and toluene 3
o Part f Weighed and poured into the front tank of the manufacturing equipment.

After stirring with a homogenizer for 10 minutes or more, the mixture was fed under pressure to a sand mill device with a pump. After 15 minutes, the first stage sand mill device was rotated, and after another 15 minutes, the second stage was rotated. Continuous operation was carried out in this state, but the paint that came out during the first 30 minutes was returned to the front tank.

After the dispersed paint accumulated in the paint tank to some extent, it was pumped into the coating tank. When the paint began to overflow from the coating tank and had accumulated in the paint tank, the sand mill equipment and pumps were completely stopped. Thereafter, the dispersion process was performed when the amount of paint decreased.

After the substrate was immersed in the coating tank, it was pulled up at a rate of 18' Own/min. After air drying for 5 minutes, it was cured at 170° C. for 30 minutes. In this way, a 15 μm thick undercoat layer was formed. This layer was formed to cover scratches and irregularities on the surface of the substrate. On top of the undercoat layer formed in Example 2, a polyamide resin (trade name: Amilan CM8000) was applied using another coating device. A 4% methanol solution (manufactured by Toshi Co., Ltd.) was applied to form a resin layer with a thickness of 0.5 μm. This is to improve the charge injection properties of the photosensitive layer to be formed next.

An electrophotographic photoreceptor manufacturing apparatus as shown in FIG. 2 was used. However, at this stage, the sand mill device was a four-stage continuous type. The flow rate of the pump 14 was 50 m11 minutes. The filter was a 25μ filter, and then a 5μ filter (Tocel TCW-5R8, manufactured by Toyo Roshi) was connected to form two filters.

In a paint tank 40 equipped with a solvent dropper, 10 parts of a disazo pigment having the following structural formula were added, including a total of 6 parts of cellulose acetate butyrate resin (product name: CAB-381; Eastman Chemical #1 and 60 parts of cyclohexane 2F). After straining and mixing well, it was poured into the front tank. After stirring with a homogenizer for more than 15 minutes, the pump was activated to start pressure feeding. The sand mill device was rotated one stage every 30 minutes. All four stages rotated. After continuous operation, the paint that came out was returned to the front tank for the first hour.After that, the paint that came out was stored in the paint tank, but at this time, the paint that came out was returned to the front tank. Methyl ethyl ketone was dropped in an amount equal to the volume of the paint that had arrived.

When the paint overflowed into the coating tank and enough paint had accumulated to allow sufficient liquid circulation, the disperser was stopped, and from then on, when the paint decreased, the paint was dispersed.

The substrate provided with the polyamide resin layer was immersed in this coating tank and pulled up at a speed of 160 mm/min. It was dried at 60° C. for 10 minutes to form a charge generation layer with a thickness of 0.1 μm.

Although the disazo pigment used here tends to re-agglomerate even after being dispersed, it was possible to apply it efficiently by using the apparatus according to the present invention.

Next, 10 parts of a hydrazone compound having the following structural formula and 20 parts of a styrene-methyl methacrylate copolymer resin (trade name: M8-200, manufactured by Nippon Steel Chemical) were dissolved in 90 parts of toluene. This liquid is applied to another coating device 6'.
It was coated on the charge generation layer and dried at 100° C. for 1 hour to form a charge transport layer with a thickness of 16 μm.

An electrophotographic photoreceptor was manufactured as described above.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a sand mill device used in the device of the present invention, and FIG. 2 is a schematic diagram showing embodiment si of the device of the present invention. 1: Sand mill device container (vessel), 2: Inlet,
3: Impeller, 4: Rotating shaft, 5: Gap/6: Outlet, 11: Paint before fraction, 12: Front tank, 13: Stirrer, 14: Pump, 15: Sand mill device, 16: Motor, 17: Filter, 18: Valve, 30: Substrate of electrophotographic photoreceptor, 31: Holding member, 32: Lifting member, 33 Niscrew screw, 34: Lifting motor, 40:
Paint tank, 41: Paint after dispersion, 43: Pump, 44
: Application tank, 45: Receiver is plate, 46: Paint. Figure 1

Claims (2)

[Claims] (1) An apparatus for manufacturing an electrophotographic photoreceptor by coating a photosensitive material paint in which a pigment is dispersed onto a substrate by a dip coating method, which includes a sand mill device for dispersing the pigment, a filter for filtering the dispersed paint, and a filter for filtering the dispersed paint. A coating tank for dip coating the paint onto the substrate is installed continuously, and the dispersed paint is dried on the paint surface, re-agglomerated, pigments increased, viscosity increased, etc.
Or, before it becomes dull, it passes through a filter,
An apparatus for manufacturing an electrophotographic photoreceptor, characterized in that the paint is supplied to a coating tank, and the paint overflowing from the upper part of the coating tank is circulated and supplied to the coating tank by passing through the filter again. (2) It has a paint tank that stores the paint dispersed by the sand mill device and the paint that overflows from the top of the coating tank.
Claim (1) is characterized in that the paint tank is provided with a mechanism for detecting the amount of paint, and when the paint decreases by a certain amount, a sand mill device is driven to supply the paint. An apparatus for manufacturing an electrophotographic photoreceptor as described in 1.