JP3030440B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated electrophotographic photoreceptor, and more particularly, to a seamless belt-shaped electronic device used in an analog or digital copying machine, a laser printer, a facsimile, and the like. The present invention relates to a method for manufacturing a photoconductor.

[Conventional technology]

Endless belt-shaped photoconductors are often used in electrophotographic copying machines, laser printers and the like. This is because in a copying machine using a cylindrical photoreceptor, it is necessary to provide a charger, an exposure system, a developing device, a transfer / separation device, a cleaning device, etc. around it, but if an endless belt-shaped photoreceptor is used, This is largely because the arrangement of such devices can be selected freely.

By the way, as such an endless belt-like substrate,
2. Description of the Related Art Conventionally, a sheet-like member made of a resin film of polyester or the like as a base material is bonded by means such as high-frequency bonding to form a seam, and a conductive layer formed on the surface of the endless belt is widely used. However, when a photosensitive layer is formed on an endless belt having such a seam and used as a photoreceptor, it is necessary to control the image forming start position so that the image forming area does not cover the seam. In addition, it is necessary to provide means for controlling the image forming position and the like, so that the system becomes complicated and cost increases. Also,
The seam accelerates or damages the cleaning blade, which also damages the photoreceptor and causes poor cleaning. For this reason, a seamless so-called belt-shaped photoconductor without a seam is demanded.

However, in response to such demands, a seamless belt manufactured by forming a plating layer of nickel or the like on the outer surface of a cylindrical metal mold and peeling off the plating layer has been put to practical use. Since a large mechanical strength is borne by a single layer of metal such as nickel, a considerable thickness is required, and as a result, it lacks flexibility and is difficult to bend with a small radius of curvature. There is a disadvantage that molding takes time and costs are increased.

In order to solve this problem, a technique has been proposed in which a lining layer made of a flexible material that bears the mechanical strength required for the belt is provided on the inner surface of the seamless belt. In order for the nickel layer to have a higher strength, a new problem arises such that the nickel layer must be thicker than required.

In order to solve such drawbacks / problems, the applicant of the present application wrote, "After forming a non-metal layer on the outer surface of a cylindrical mold, a metal layer is added thereon, and then the non-metal layer is peeled off from the cylindrical mold. Thus, an electrophotographic photosensitive member in which a seamless belt is formed, and a photosensitive layer is provided on the surface of the belt. "(JP-A-64-13576). However, even in the production of this photoreceptor, a step of separately applying and drying a lining layer is indispensable, and the problem of increasing the number of production steps remains.

[Problems to be solved by the invention]

The present invention solves the above-mentioned problems, and the application of the back coat (reinforcing layer) of the metal seamless belt is performed simultaneously with the step of applying and drying the undercoat layer, the photosensitive layer or the protective layer, and The production process can be reduced by using a coating liquid having the same composition as the undercoating layer, the photosensitive layer or the protective layer, and the substrate can be wavy when mounted on a laser printer or the like, and the substrate can be broken, scratched, bent, or the like. And a method for manufacturing the same.

[Means for Solving the Problems] The present invention relates to a method for producing an endless seamless belt-shaped electrophotographic photoreceptor, comprising a charge generation layer forming solution, a charge transport layer forming solution on the outer surface of a metal seamless belt-shaped substrate. Are sequentially applied and dried, or if necessary, an undercoat layer forming liquid is applied and dried before applying the charge generating layer forming liquid, or if necessary, a protective layer is applied after applying and drying the charge transport layer forming liquid. Applying and drying the forming liquid, and further applying and drying a reinforcing layer forming liquid on the inner surface of the substrate to produce a laminated electrophotographic photoreceptor, the coating of the reinforcing layer is performed by dip coating. The undercoat layer forming liquid, the charge generating layer forming liquid, the charge transport layer forming liquid, and the protective layer forming liquid are simultaneously coated with the same forming liquid.

The present inventors, on the surface of a metal seamless belt-like substrate (hereinafter sometimes abbreviated as "metal seamless belt"), with or without an undercoat layer, a charge generation layer, a charge transport layer, When the protective layers are sequentially laminated as necessary, the coating and drying of any of the undercoat layer, the charge generation layer, the charge transport layer or the protective layer on the metal seamless belt surface (inner surface), and the It has been confirmed that the above-mentioned object can be achieved by forming a reinforcing layer by applying and drying a solution having the same composition as any one of the layers. The formation of the reinforcing layer is preferably performed in order to exert a sufficient reinforcing function among the above-described layers on the outer surface of the base,
It is preferable to carry out the coating simultaneously with the application of the undercoat layer, the charge transport layer or the protective layer. Furthermore, by performing the coating simultaneously with the coating of the outermost layer of the photoreceptor (the protective layer in the case of providing a charge transport layer or a protective layer), peeling off from the end of the charge generating layer and the like which may occur when the photoreceptor is used. Can be prevented, which is the most preferable manufacturing method. The present invention has been made based on such findings.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, the undercoat layer in the photoreceptor of the present invention,
The materials, thicknesses, and the like of the charge generation layer, the charge transport layer, and the protective layer are not different from those of the conventionally known laminated electrophotographic photosensitive member.

The metal seamless belt is obtained, for example, by forming a conductive seamless layer such as nickel on the outer surface of a cylindrical metal mold by plating, sputtering, vapor deposition, or the like, and then peeling the conductive seamless layer from the metal mold. be able to. The method for producing the metal seamless belt itself is a generally known method described in JP-A-48-51546 and JP-A-52-36016. The thickness of this metal seamless belt is 10-200 μm, often 20-50 μm
It is about thin.

Means such as dip coating and spray coating are generally employed to form each layer constituting the outer surface of the metal seamless belt. However, for forming the coating layer (reinforcement layer) on the inner surface of the metal seamless belt, The dip coating method is adopted. Therefore, when the reinforcing layer is formed on the inner surface of the conductive support (metal seamless belt), the undercoat layer, the charge generation layer, the charge transport layer, or the protective layer is immersed in the same composition as the coating liquid. It must be formed by a coating method.

FIG. 1 schematically shows a dip coating apparatus. The metal seamless belt 1 is attached to a support 16. By pulling up the support 16 from the coating liquid 3 (which is one of an undercoating layer forming liquid, a charge generating layer forming liquid, a charge transporting layer forming liquid, or a protective layer forming liquid) in the coating container 2,
On both front and back surfaces of the metal seamless belt 1, coating films 15 having the same composition are formed with substantially the same thickness. When the support 16 is raised, the rotation of the motor 5 is transmitted to the belt pulley 14 by the endless belt 12, and the belt pulley 14
As a result, the screw rod 6 fixed by the bearing 10 rotates,
The internal thread 8 is moved up and down according to this rotation.
A lid 4 is disposed on the support 16 at the top and bottom, and a fixing member 9 is attached to the upper lid 4.
Are fixed to the support bar 7 by screws. Support rod 7
Is fixed to the female screw 8 by a fixing member 11, and the female screw 8
The support 16 is configured to move up and down in accordance with the up and down movement of.

The film thickness of the coating film 15 is controlled by the
It is controlled by adjusting the number of revolutions and controlling the lifting speed.

FIG. 2 shows the appearance of the support 16 as viewed from above, but is not necessarily limited to such an appearance. In short, the support 16 has a form in which at least a part thereof is opened and the metal seamless belt 1 can be suspended. Anything should do.

FIG. 3 schematically shows the spray coating apparatus. Here, the metal seamless belt 1 is a belt support
Attached to 17. The belt support 17 is mounted horizontally, and is rotated at a constant speed in a certain direction by rotating a belt 20 wound around a pulley 19 of a center shaft 18. A spray gun 21 is installed in the vicinity of 17. The spray gun 21 is a scanning device 23 such as a screw in which a table 22 is installed in parallel with the axial direction of the belt support 17.
A pipe 25 for leading the carrier gas to the ejection nozzle 24 at the tip is provided, and a coating solution pipe 27 from the coating solution tank 26 is provided for the application of the carrier gas from the ejection nozzle 24. And a gas pressure adjusting valve 28 is attached to the pipe 25.

The application of the photosensitive liquid or the like to the metal seamless belt is performed by rotating the belt with the metal seamless belt attached to the belt support 17 and scanning the spray gun with the scanning device 23 together with the carrier gas adjusted by the gas pressure adjusting valve 28. This is performed by spraying the coating liquid in the coating liquid tank 26 and spraying the coating liquid on the seamless belt.

In the present invention, as described above, at least one of the undercoat layer, the charge generation layer, the charge transport layer, and the protective layer is formed by a dip coating method. Therefore, for example, the undercoat layer and the charge generation layer are formed by a spray coating method. The formation of the charge transport layer and the reinforcing layer may be carried out once by a dip coating method.

〔Example〕

 Here,% is based on weight.

Example 1 Sodium polystyrene sulfonate 15 g Purified water 100 g Polyamide resin 700 g (Methanol solution manufactured by CM-8000 Toray, solid content 19.2
%) A mixture consisting of 200 g of methanol is used as the resin solution.

Take 450.0 g of this resin solution and 90.0 g of titanium oxide (TA-300, manufactured by Fuji Titanium Industry Co., Ltd.) in a ball mill pot,
Use 3/8 inch alumina balls as mill members,
After primary milling for an hour, the remaining resin solution 56
5 g was added and secondary milling was performed for 1 hour.

After milling, the mill base was taken out, and methanol and n-butanol were added and diluted and stirred so that mill base / methanol / n-butanol = 1 / 0.3 / 0.2.
Further, this liquid / methanol / n-butanol was diluted and stirred so as to be 1/1/1 to prepare an undercoat layer spray coating liquid.

The undercoat layer coating solution was spray-coated on a nickel electroformed seamless belt having a thickness of about 30 μm, and touch drying was performed for 5 minutes. The thickness of the undercoat layer was about 3.5 μm. Here, "touch drying" means that the coating is left at room temperature after application and dried to such an extent that it does not remain after touching with a finger.

Next, the following composition Trisazo pigment of the following formula (I) 25 g Butyral resin (XYHL, manufactured by UCC) 4.2 g Cyclohexanone 365 g Was placed in a ball mill pot, and primary milling was performed for 48 hours using a 3 / 8-inch menor ball, followed by addition of 600 g of cyclohexanone and secondary milling for 24 hours.

After milling, take out the mill base, add cyclohexanone so that the solid concentration becomes 0.9%, and dilute.
The mixture was stirred to prepare a liquid for forming a charge generation layer. This coating solution is
Spray on the undercoating layer in the same way as the undercoating layer,
For 20 minutes to form a charge generation layer having a thickness of about 0.2 μm.

Subsequently, a charge transporting material of the following composition (II) (manufactured by Ricoh) 70.0 g polycarbonate resin 100.0 g (C-1400, manufactured by Teijin Chemicals) dichloromethane (manufactured by Kanto Kagaku) 866.0 g silicon oil (KF-50) , Shin-Etsu Chemical Co., Ltd.) 0.002g The charge transport layer forming solution (coating solution for dip coating) is prepared, and the surface and the back surface of the metal seamless belt on which the undercoat layer and the charge generating layer are already applied are formed by the apparatus shown in FIG. The solution was applied by dip coating and dried by heating at 130 ° C. for 20 minutes. The film thickness is about 25 μm on the surface (charge transport layer) side,
The back (reinforcing layer) side was about 22 μm.

The electrophotographic photoreceptor thus obtained was mounted on a modified electrophotographic copying machine (FT2070, manufactured by Ricoh Company) to form a copied image, and this was repeated 60,000 times.
A clear image was obtained.

For comparison, in the same manner as described above except that the reinforcing layer (layer having the same composition as the charge transport layer) on the back side of the metal seamless belt was omitted (however, the charge transport layer was formed by a spray coating method). I made an electrophotographic photoreceptor.

When this electrophotographic photosensitive member was evaluated in the same manner as in Example 1, the nickel belt was wavy at the 15,000th sheet, and density unevenness occurred in the halftone image.

Example 2 The undercoat layer forming liquid used in Example 1 was applied to both surfaces of a nickel electroformed seamless belt having a thickness of about 30 μm by the dip coating apparatus shown in FIG. 1, and dried by heating at 130 ° C. for 10 minutes. ,
An undercoat layer having a thickness of about 3.5 μm and a reinforcing layer having a thickness of about 3.5 μm were formed. Subsequently, a charge generating layer (about 0.2 μm) and a charge transporting layer (about 25 μm thick) having the same composition as in Example 1 were formed on the undercoat layer to produce an electrophotographic photosensitive member.

This electrophotographic photosensitive member was repeated 60,000 times in the same manner as in Example 1, and a clear image was obtained.

For comparison, in the same manner as described above except that the reinforcing layer (layer having the same composition as the undercoat layer) on the back side of the metal seamless belt was omitted (however, the undercoat layer was formed by a spray coating method). I made an electrophotographic photoreceptor.

When the electrophotographic photoreceptor was evaluated in the same manner as in Example 1, the nickel seamless belt was wavy at the 15,000th sheet, and density unevenness occurred in the halftone image.

〔The invention's effect〕

 According to the present invention, the following effects are provided.

(1) The back surface coating (formation of the reinforcing layer) of the metal seamless belt can be performed without changing the manufacturing method of the metal seamless belt used so far.

(2) Since the backside coating can be performed simultaneously with the undercoat layer or photosensitive layer application step without adding a backside coating step, the number of manufacturing steps can be reduced as compared with conventional means.

(3) By coating the back surface of the photoreceptor belt, the occurrence of breakage, scratches, bending, and the like of the substrate during handling can be reduced.

(4) When the photoconductor belt is mounted on a laser printer or the like, the substrate does not undulate when the belt is driven, and density unevenness and background contamination on an image can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a dip coating apparatus useful for carrying out the method of the present invention. FIG. 2 is a plan view of an example of a metal seamless belt holder. FIG. 3 is a schematic view of an example of a spray coating apparatus useful for carrying out the method of the present invention. DESCRIPTION OF SYMBOLS 1 ... Coated object 2 ... Coating container 3 ... Coating liquid 4 ... Lid 5 ... Motor, 6 ... Screw rod 7 ... Support rod, 8 ... Female screw 9 ... Fixing member, 10 ... … Bearing 11… Fixing member 12… Endless belt 13… Coating device controller 14… Belt pulley 15… Coating film 16… Belt support 17… Belt support 18… Center Axis 19: Pulley, 20: Belt 21: Spray gun, 22: Stand 23: Scanning device, 24: Spray nozzle 25: Pipe, 26: Coating liquid tank 27: Coating liquid pipe, 28 …… Gas pressure control valve

Continued on the front page (72) Inventor Kazuya Ishida 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Izumi Aiso 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company (56) References JP-A-62-280752 (JP, A) JP-A-61-139048 (JP, A) JP-A-60-238837 (JP, A) JP-A-1-223467 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 5/00 101 G03G 5/10

Claims (2)

(57) [Claims] 1. A liquid for forming a charge generation layer and a liquid for forming a charge transport layer are sequentially coated on the outer surface of a metal seamless belt-like substrate.
Dry, or if necessary, apply and dry the undercoat layer forming liquid before applying the charge generating layer forming liquid, or apply the protective layer forming liquid after applying and drying the charge transport layer forming liquid as needed.・ Drying, and further applying and drying a reinforcing layer forming liquid on the inner surface of the base to produce a laminated electrophotographic photoreceptor, the coating of the reinforcing layer is performed by dip coating to form the undercoat layer. A method for producing an electrophotographic photoreceptor, wherein the method is carried out simultaneously with and using the same forming liquid as the forming liquid, the charge generating layer forming liquid, the charge transport layer forming liquid, and the protective layer forming liquid. 2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the application of the reinforcing layer is performed simultaneously with the outermost layer of the photoreceptor (application of the charge transport layer or the protective layer).