JP2606289B2 - Method of manufacturing seamless belt for electrostatic recording - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a seamless belt for electrostatic recording.

2. Description of the Related Art Electrostatic recording is used in many fields because of its excellent recording speed, sharpness of recording, storability of recording, and the like. The electrostatic recording medium used for electrostatic recording is typically a sheet-like one in which a dielectric layer made of an insulating resin is formed on a conductive substrate. It is used by being wound around a pipe or as a seamed belt type formed into a belt by a method such as ultrasonic welding at both ends.

Conventionally, in order to manufacture this type of electrostatic recording medium, a conductive coating is applied on a dielectric support by a bar coater, a gravure roll coater, an air knife coater or the like to form a conductive layer from a sheet member. It is processed into a belt shape.

By the way, in the case of a seamed belt type electrostatic recording medium,
Unlike a drum-type electrostatic recording medium, there is an advantage that the shape of the electrostatic recording medium can be made freely, and thus the arrangement of subsystems in the electrostatic recording apparatus can be varied. By using this, it is possible to use it as a superimposable intermediate drawing, which is effective for realizing the miniaturization and multifunctionalization of the machine.

However, in the conventional seamed belt type electrostatic recording medium, since a sheet-like material is bonded as described above, there is a portion or a bonding portion where no electrostatic recording layer exists, and high-quality recording is performed in this portion. Can not do. For this reason, there is no advantage that a large area can be recorded even with a small circumference, unlike a drum-type electrostatic recording medium, and an electrostatic recording medium having an area larger than that of copy paper is required. Cannot be realized.

Problems to be Solved by the Invention By the way, there are several known methods for producing a seamless belt, such as extrusion molding, inflation, blow molding, dip coating (Japanese Patent Application Laid-Open No. 61-273919), and spray coating. I have.

However, in the case of the extrusion molding method, the inflation method, or the blow molding method, it is difficult to obtain a structure in which a dielectric layer is laminated on a conductive layer. Further, electrostatic recording belts formed by other known methods are still at an insufficient level in terms of dimensional stability, surface properties, etc., for practical use as electrostatic recording belts.

Also, a method of sequentially applying a coating liquid for forming a dielectric layer and a conductive layer to the pipe surface by a dip coating method, a spray coating method, or the like, and then peeling off the formed coating film can be considered. Since shrinkage occurs and stress is applied to the method of compressing the pipe, it is difficult with this method to peel off the seamless layer formed on the pipe surface from the pipe.
Further, even if a release agent is applied to the surface, it has been difficult to improve it.

Furthermore, when using a method of applying a resin coating solution on a flexible seamless metal foil belt by a dip coating method and then bending the metal foil belt to peel off the seamless belt, the surface of the belt is controlled to be smooth. Not easy.

As described above, a method for producing a satisfactory seamless belt that can be practically used as an electrostatic recording medium has not been established yet.

The present invention has been made in view of the above-described problems in the related art.

An object of the present invention is to provide a method for easily obtaining a seamless belt for electrostatic recording having good surface properties.

Means and Means for Solving the Problems The method for producing a seamless belt for electrostatography of the present invention comprises:
A first step of immersing a jig having a smooth cylindrical inner surface in a resin solution contained in a dip coating tank and forming an insulating resin layer on the cylindrical inner surface of the jig by lifting the jig;
A second step of forming a conductive layer on the insulating resin layer by immersing the jig in which the insulating resin layer is formed on the inner surface of the cylindrical shape in a conductive coating solution contained in a dip coating tank and pulling up the jig; And a third step of peeling the coating material from the jig.

FIG. 1 shows an example of a schematic configuration of a dip coating apparatus used in the present invention, wherein 1 is a cylindrical jig such as an aluminum pipe, 2 is a pipe chuck apparatus, 3 is a coating tank, and 4 is a coating tank. The liquid 5 is a liquid leakage prevention collar attached to a cylindrical jig for preventing the application liquid from adhering to the outer surface of the pipe.

In the present invention, first, a cylindrical jig 1 such as an aluminum pipe having a smooth inner surface is fixed to a pipe chuck device 2 and immersed in a resin solution stored in a coating tank 3. Next, the cylindrical jig is pulled up to form an insulating resin layer on the inner surface. Next, using a similar coating tank containing a conductive coating liquid, immersing the cylindrical jig therein,
Then, by pulling up, a conductive layer is formed on the insulating resin layer. The coating material having a laminated structure formed on the inner surface of the cylindrical jig is then peeled off.

As a method of peeling off the applied material, slowly peel off the entire circumference of the jig from the end of the jig, peel off part of the applied material with a sharp object like a spatula, and slowly peel off the entire circumference After peeling off a part of the coating, air is blown between the jig and the insulating resin layer by an air gun, and the whole is peeled off. By heating or cooling, the adhesion between the jig and the coating is reduced. After that, various methods such as peeling using a spatula, air, steam or the like are used.

If the end of the belt becomes uneven compared to the center due to the influence of the end of the jig during coating or dripping of the coating solution, it is preferable to cut both ends of the belt. For cutting, a roller with a smaller diameter is passed through the belt, another roller with two disk-shaped cutters is applied, and both rollers are rotated to cut both ends. Various methods can be used, such as a method of passing a small-diameter cylinder through the belt loop and cutting both ends with a guillotine-type cutter.

The jig having a smooth cylindrical inner surface that can be used in the present invention has a cylindrical space inside, such as a pipe-shaped jig or a lump having a hollow inside. Any shape may be used as long as the inner surface is smooth and a coating film can be formed by a dip coating method.

As the material of the jig, any material can be used as long as it is not affected by the solvent used.For example, aluminum, nickel, iron or stainless steel, etc., various metals, synthetic resins such as Teflon or polyethylene, etc. can give. Further, composites in which metal surfaces are coated with Teflon or polyethylene or the like can also be used.

In order to improve the releasability, a release agent may be applied to the inner surface of the jig in advance, or the release agent may be mixed in the coating solution. As such a release agent, known ones are used, and for example, zinc, calcium or magnesium salts of higher fatty acids such as stearic acid, and dioctyl phosphate estelmonoethanolamine salt are preferably used.

In the present invention, since the surface property of the seamless belt for electrostatic recording is determined by the surface property of the inner surface of the jig, the inner surface of the jig is mirror-finished in advance, thereby having a very smooth surface. A seamless belt for electrostatic recording can be obtained.

In the present invention, various resins can be used as the resin used for the resin solution for forming the insulating resin layer to be the dielectric layer for electrostatic recording. For example, polyimide resin, polyamideimide resin, polybenzimidazole resin, polyphenylene sulfide resin, polyetherketone resin, fluororesin, aramid resin, silicone resin, polyetherimide resin, polymaleimide resin, polyparapanic acid resin, polyesterimide resin , An epoxy resin, a polyoxadiazole resin, a polyacrylate resin, a polyether sulfone resin, a polyethylene naphthalate resin, a polyhydantoin resin, a polysulfone resin, a polycarbonate resin, a polyurethane resin and the like can be used alone or as a mixture.

The conductive paint for forming the conductive layer is made of a resin solution in which a conductive material is dispersed. The resin described above can be used as the resin. As the conductive material, for example, conductive powders such as carbon, ITO, tin oxide, antimony oxide, tungsten oxide, and molybdenum oxide or metal whiskers can be used.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist is not exceeded.

Example 1 As shown in FIG. 1, an aluminum pipe 1 having an inner diameter of 120 mmφ with an inner surface mirror-finished was used as a cylindrical jig 1 by attaching a liquid leakage prevention collar 5 to prevent the application liquid from adhering to the outer surface of the pipe. It was fixed by the pipe chuck device 2. This aluminum pipe is placed in a coating solution placed in a coating tank 3, that is, a bisphenol Z type polycarbonate (molecular weight 7) having a solid content of 12% by weight in methylene chloride.
7,000) was dissolved in the coating solution, and pulled up at a speed of 80 mm / min to apply the resin solution to the inner surface of the aluminum pipe. After removing the aluminum pipe from the pipe chuck, the aluminum pipe was dried at 120 ° C. for 10 minutes to form an insulating resin layer having a thickness of 50 μm.

Next, a conductive layer was formed on the insulating resin layer. The conductive coating solution is tin oxide 40% by weight and polyurethane resin (desmophen 651 manufactured by Sumitomo Bayer Urethane Co.) 60
% By weight was dispersed in n-butanol so as to have a solid content of 5% by weight, and then a curing agent (Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added by 20% by weight to the polyurethane resin. After dipping the above aluminum pipe in this conductive paint and pulling it up at a speed of 70 mm / min,
It was dried and cured at 0 ° C. for 5 hours to form a conductive layer having a thickness of about 10 μm.

Then, between the inner surface of the aluminum pipe and the insulating resin layer, after inserting a spatula having a sharp tip to partially peel off, slowly peeling the applied material from the peeled portion,
Further, by cutting both ends, a seamless belt for conductive recording having a smooth surface was obtained.

Example 2 Dip coating was performed in the same manner as in Example 1 using the same apparatus. That is, 17% by weight of a polyimide (copolymerized product of benzophenonetetracarboxylic dianhydride and 4,4'-diisocyanodiphenylmethane, 2,4-diisocyanotoene) and 0.4% by weight of dioctyl phosphate monoethanol Release agents consisting of amines (Separ 44-100,
In the dimethylformamide solution of Chukyo Yushi Co., Ltd.)
The aluminum pipe was immersed, pulled up at a speed of 300 mm / min, and dried at 200 ° C. for 10 minutes to form an insulating resin layer having a thickness of 40 μm.

Next, a conductive layer was formed on the insulating resin layer. That is, the above aluminum pipe was immersed in a solution obtained by diluting a conductive paint (Totite R-121, manufactured by Fujikura Kasei Co., Ltd.) five-fold with n-butyl alcohol, and pulled up at a speed of 200 mm / min. The resultant was dried and cured at 4 ° C. for 4 hours to form a conductive layer having a thickness of 3 μm.

Next, a spatula having a sharp tip is inserted between the inner surface of the aluminum pipe and the insulating resin to partially exfoliate, and then air is injected into the exfoliated portion by an air gun to apply the coating material from the inside. Was peeled off, and the both ends were cut to obtain a seamless belt for electrostatic recording having a smooth surface.

Advantageous Effects of the Invention Since the present invention has the above-described configuration, it is uniform,
A seamless belt for electrostatic recording having a smooth surface can be easily obtained. The seamless belt formed by the method of the present invention has good dimensional stability and can be advantageously used as an electrostatic recording medium.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dip coating apparatus used in the present invention. 1 ... cylindrical jig, 2 ... pipe chuck device, 3 ...
Coating tank, 4 ... Coating liquid, 5 ... Color to prevent liquid leakage.

Claims (1)

(57) [Claims] 1. A first method for forming an insulating resin layer on a cylindrical inner surface of a jig by dipping a jig having a smooth cylindrical inner surface into a resin solution contained in a dip coating tank and pulling up the jig. A step of forming a conductive layer on the insulating resin layer by immersing the jig in which the insulating resin layer is formed on the inner surface of the cylindrical shape in the conductive coating solution contained in the dip coating tank and pulling up the jig; A second step and a third step of peeling the coating material from the jig
A method for producing a seamless belt for electrostatic recording, comprising the steps of: