JPS5831576B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

Description

Detailed Description of the Invention The present invention involves coating a photoconductive emulsion obtained by dispersing or adsorbing a phthalocyanine photoconductive emulsion and a sensitizer in a binder resin solution on a conductive support, and drying the emulsion. The present invention relates to a method for producing an electrophotographic photoreceptor that is highly sensitive to visible light and has excellent properties such as mechanical strength and flexibility.

The basic technology of electrophotography has been well known and is based on the following method.

Inorganic compounds such as selenium, zinc oxide, lead oxide, cadmium sulfide, cadmium selenide, zinc sulfide, or organic compounds such as anthracene, perylene, acridine, phthalocyanine, quinacridone, polyvinylcarbazole, polyacenaphthylene, etc. The surface of a photoreceptor using a compound as a photoconductor element is uniformly charged, and then the electrostatic charge on the photoconductor layer is partially erased using visible light or actinic light to form an electrostatic latent image. .

This electrostatic latent image is visualized using a coloring agent called toner and a finely divided developer contained in the resin, and the resulting toner image is transferred to paper or other receiving material, and then heated, pressed, etc. It is fixed to the receptor using a suitable fixing method.

Photoreceptors made of vapor-deposited layers using photoconductor elements such as selenium have physical shortcomings such as flexibility, and zinc oxide,
In a photoreceptor in which a photoconductor element such as cadmium sulfide is dispersed in a resin, electrophotographic properties cannot be obtained unless the content of the photoconductor element is increased, and in order to increase the content of the photoconductor element, There is a need for improvements in the physical properties of photoconductor devices.

Photosensitive layers using organic compounds as photoconductor elements have a simple manufacturing process and excellent physical properties, but their electrophotographic properties are poor, and various sensitization methods have been proposed to improve practical sensitivity. However, nothing that is fully satisfactory is known yet.

In addition, polyvinylcarbazole-based photoconductor elements (PVK
) and an organic-inorganic photoconductor such as selenium are also known.

An example of these photoreceptors is a photoreceptor in which a PVK layer is provided on a conductive support and a selenium layer is further provided on top of the PVK layer, because it is difficult to maintain transparency unless the selenium layer is thin. The manufacturing process was difficult, and because the selenium layer lacked flexibility, careful attention had to be paid to the composition of the intermediate PVK layer, making it difficult to create a composition with good electrophotographic properties such as sensitivity. .

A method of providing a selenium layer on a conductive support and a PVK layer thereon is also known, and the PVK layer maintains sufficient transparency and has good printing durability.

And there is almost no PVK layer with excellent sensitivity, so it is very sensitive to electrons.

It could not be called a photographic photoreceptor.

Electrophotographic photoreceptors using phthalocyanine are also known, and have excellent properties not found in inorganic photoconductive materials, such as flexibility, processability, non-toxicity, and cutting resistance.

The manufacturing method for electrophotographic photoreceptors as described above is carried out by vapor deposition, or in the case of photosensitive liquids, roll coating, reverse coating, or spray coating, but it is difficult to control the coating thickness and is not suitable for high-speed production. Ta.

The object of the present invention is to have simple and easy production, high yield, and therefore low cost, no problems with disposal or pollution, and furthermore, to have excellent electrophotographic properties and various physical properties.

In the present invention, a photoconductive emulsion in which a phthalocyanine photoconductor element and a sensitizer are dispersed in a binder resin solution is applied to an aluminum foil and a polyester film using a gravure cylinder with a plate depth of 30 microns to 100 microns. This is a method for producing an electrophotographic photoreceptor, which is characterized in that it is coated on a laminated composite conductive support and dried.

Although any method of formation may be used, the gravure coating method is advantageous for industrially inexpensive and mass production, and also has excellent flexibility, mechanical strength, printing durability, etc. A photoreceptor can be obtained.

The phthalocyanine according to the present invention can be either a metal phthalocyanine such as copper, cobalt, or nickel, or a metal-free phthalocyanine. Various crystal forms are known for phthalocyanine, and any crystal form is possible. However, it must have at least photoconductivity.

Fortunately, JP-A-1987 has good electrophotographic characteristics such as sensitivity.
-109841 is a copper phthalocyanine that shows three strong lines with diffraction angles of 2θ ± 0.2 degrees of 7.0, 7.7, and 9.2 degrees in the X-ray diffraction diagram of CuKa.
Alternatively, it is an ε-type copper phthalocyanine shown in JP-A-50-38543, or a metal-free phthalocyanine.

As an example of a method for producing these copper phthalocyanines, copper phthalocyanine having an ε-type crystal form is prepared by
There is a method of milling using mechanical strain at 20°C.

ε-type copper phthalocyanine is produced by the production method described in Japanese Patent Publication No. 40-2780, that is, between phthalic anhydride and steel or copper salt and urea or between phthalodinitrile and copper or in the presence or absence of a catalyst. In the production method by integrating copper salt and urea,
The total amount of urea used is 3 to 1.5 times the weight of phthalic anhydride or phthalodinitrile, and phthalic anhydride or phthalodinitrile is added little by little into the molten system containing excess urea. 1 selected from the group consisting of a production method in which a salt □ ring is performed after a condensation reaction, or copper phthalocyanine and a phthalocyanine derivative with a substituent introduced into the benzene nucleus, a phthalocyanine nitrogen isoform, a metal-free phthalocyanine, and a metal phthalocyanine outside the copper plate. It is a copper phthalocyanine obtained by a manufacturing method (Japanese Patent Application Laid-open No. 76925.49-59136) in which one or more seeds are □-ringed at 80 to 200° C. under strong mechanical strain.

The sensitizers used in the present invention include various chemical sensitizers, including nitrile compounds such as tetracyanoethylene, trinitroanthracene, 2, 4, 5, 7, etc.
, heterocyclic or polycyclic nitro compounds such as tetranitrofluorenone, 2°4.7 trinitrofluorenone, quinones such as anthraquinone, aromatic amines such as tetramethyl-P-phenylenediamine, etc., but especially 2,4. ,7
) IJ nitro-9-fluorenone and 2,4,5,
7-tetranitro, 9-fluorenone, or a mixture of both forms a good photoreceptor.

The above-mentioned phthalocyanine photoconductor element and sensitizer are mixed into a binder resin and kneaded using a method such as a ball mill to obtain a photoconductive material.

Binder resins that can be used at this time include phenolic resin, urea resin, melamine resin, furan resin, epoxy resin, silicon resin, polyurethane resin, xylene resin, toluene resin, vinyl chloride-vinyl acetate copolymer, and vinyl acetate copolymer. Various resins having insulating properties such as methacrylic copolymers, acrylic resins, polycarbonate resins, and fiber derivatives have specific resistances of 1070 m or more.

Alternatively, it can be formed on the surface of the support by vapor deposition, but as mentioned above, it is inferior in terms of printing durability, flexibility, etc., and it is preferable to disperse it in a binder resin.

As a result of examining the binder resins that can be used in the present invention, taking into consideration electrophotographic properties, flexibility, little deterioration of mechanical strength, and adaptability to gravure coating methods, etc., OH value is 30 to 60. Among them, 40 acrylic polyol and an acrylic resin which is a copolymer of methyl methacrylate and methacrylic acid and has a monomer ratio of 9/1 to 1/1 (weight solid content ratio), preferably 1 or 8/2, 1
It was concluded that the most excellent binder resin is a resin obtained by mixing at a weight/solid content ratio of /1 to 9/1 and further adding an amount of isocyanate compound corresponding to the OH equivalent of the acrylic polyol. .

A suitable solvent is added to the obtained photoconductive material to form a photosensitive emulsion, which is then formed on a conductive support by gravure coating.

When the photoconductive emulsion according to the present invention is formed by gravure coating, the viscosity of the photoconductive emulsion is from 600 eps to 900 cps1, especially 750 cps, by using a gravure cylinder having a plate depth of 30 μ to 100 μ, especially 70 μ to 80 μ. By coating a photoconductive emulsion having Newtonian flow properties and subjecting it to a suitable drying treatment, a photoreceptor having uniform and good smoothness can be obtained.

A hot air dryer at 100°C to 150°C is sufficient for drying, and there is no blocking or other stains.

In addition, various types of conductive supports related to the present invention (C) can be used, such as commonly used aluminum plates and conductive-treated paper, but the mechanical strength, suitability for gravure coating, flexibility, In consideration of heat resistance and the like, the best results can be obtained with a composite in which a polyester film of 50 to 100 μ, preferably 75 μ is laminated to an aluminum foil of 5 μ to 20 μ, preferably tL<15 μ.

A more detailed explanation will be given below according to examples.

In the button examples, "parts" indicate parts by weight, and "sensitivity"
is shown based on the irradiation amount required to reduce the potential of the electrophotographic photoreceptor 9 by 50% immediately before exposure (the exposure amount for half-attenuation of the charge).

The mixture was mixed according to the above recipe, kneaded in a porcelain ball mill at room temperature for 30 hours, and 61 parts of Tolylene diisocyanate 2 (Coronet) L (manufactured by Nippon Polyurethane) was added.

Adding methyl ethyl ketone to the resulting photoconductive material,
Adjust the viscosity to approximately 750 ops using a B-type viscometer.

Next, a gravure cylinder with a plate depth of 70μ is used to create a thickness of 1
It is coated on a laminate of 5μ aluminum foil and 75μ thick polyester film and dried at a drying temperature of 100°C.

At this time, the thickness of the photosensitive layer! -j: It was 10μ. The obtained photoreceptor was further subjected to secondary drying at 150'C for 10 minutes.
It is stored in a dark place at 5° C. and 50% humidity for 24 hours to prepare a photoreceptor for electrophotography.

The surface of the photoreceptor obtained in this way was tested in a dark place.
A corona discharge is applied for 30 seconds with a 55 KV corona gap of 10 m, and 30 seconds after the corona discharge is stopped, exposure is performed at an illumination intensity of 10 Lux using a tank sten light source at 2854°.

The maximum surface charge amount was 550 V, and the dark decay rate of the potential after 30 p was 9.9% with respect to the potential 5 seconds after the end of charging.

Half-attenuation exposure of the charge of the photoreceptor of the housing octopus 1t18.5L
It was ux・5econd.

Using this photoreceptor, an image was created by the development and transfer method described below.

A positive film charge is given to the photoreceptor by corona discharge, and a positive film original image is
Lux is projected for about 1/10 seconds to form an electrostatic latent image on the photoreceptor, and a visible image is obtained using negatively charged toner.

A piece of high-quality paper was placed on top of it, and a visible image was transferred from the back of the paper using a positively charged carbon brush electrode with an applied voltage of 450 V, and then heated and fixed using an infrared lamp.

The resulting image was extremely faithful to the original, clean, clear, and had high contrast.

Moreover, this photoreceptor withstood repeated practical use and exhibited excellent printing durability.

Mix according to the above recipe, knead at room temperature for 30 hours in a porcelain ball mill, add Desmodur N-75 (Nippon Polyurethane Co., Ltd., hexamethylene diisocyanate), further add cellosolve acetate, and measure using a B-type viscometer. The viscosity was adjusted to approximately 600 cps.

Next, using a gravure cylinder with a plate depth of 90μ,
A laminate made of μ-thick aluminum foil and 75 μ-thick polyester film is gravure coated and dried at 130° C. around the button to give a film thickness of 8 μm.

The obtained photoreceptor was further subjected to secondary drying at 150°C for 10 minutes, and stored in a dark place at 25°C and 50% humidity for 24 hours.
Used as a photoreceptor for electrophotography.

When this photoreceptor was corona charged at +5.5KV, the maximum surface charge amount was 620V, and the half-attenuation exposure amount was 11V.
It was Lux 0 seconds.

A positive charge was given to this photoreceptor by corona discharge, and 100W was applied.
Positive using a tungsten light source for enlargement.

An original film image is projected at 10 Lux for about 2 seconds to form an electrostatic latent image on the surface of the photoreceptor, and then a visible image is obtained using negatively charged toner.

A piece of high-quality paper was placed on top of it, and a visible image was transferred from the back of the paper using a positively charged carbon brush electrode at an applied potential of 550 V, and then heated and fixed using an infrared lamp.

The obtained image was a bright image with strong contrast.

Example 3 Mix according to the above recipe, knead at room temperature for 48 hours in a porcelain ball mill, further add M, E, and K and adjust to approximately 700 cps with a B-type viscometer, and measure photoconductivity. as a drug.

This photoconductive emulsion was coated onto the same laminate as in Example 2 using a gravure plate with a depth of 60μ and a cylinder.
Dry at ℃ to obtain a photoreceptor.

The maximum surface charge amount, dark decay rate, and half decay exposure amount of the obtained photoreceptor were measured in the same manner as in Example 1.
The maximum surface charge amount was 600V, the dark decay rate was 5.4 yen, and the half-attenuation exposure amount was 8.5 Lux -5econd, and it was found to be a sensitive material with extremely high sensitivity and good storage stability. Ta.

When an image was created using this photoreceptor in the same manner as in Example 1, a clear image faithful to the original was obtained, and the photoreceptor withstood repeated practical use and exhibited excellent printing durability. .

Mix according to the above recipe and use a porcelain bowl for 30 minutes.
The mixture was kneaded with ordinary salt for an hour, 1161 parts of Coroho was added, and appropriate amounts of M, E, and K were added to adjust the viscosity to about 650 cps. Example 2 An electrophotographic photoreceptor is obtained in the same manner as above.

Various properties of the obtained photoreceptor were measured in the same manner as in Example 1. As a result, the maximum surface charge amount was 670V and the dark decay rate was 9.
2nd stage, half-attenuation exposure amount 6.5 Lux -5econd
Met.

When an image was formed on this photoreceptor in the same manner as in Example 1, a clear image with no difference from the original image was obtained, and the photoreceptor sufficiently withstood repeated copying use.

The mixture was kneaded for 30 hours at room temperature according to the above recipe, 8.4 parts of hexamethylene diisocyanate was added, and an appropriate amount of cellosolve acetate was added to adjust the viscosity to about 600 cps, and the resulting photoconductive emulsion was mixed. coated using a gravure cylinder onto a photoconductive support consisting of a 15μ aluminum foil layer and a 75μ polyester layer;
A photoreceptor was obtained by drying and secondary drying.

When an image was formed on the obtained photoreceptor in the same manner as in Jitori Example 2, a clear and vivid image with vivid contrast was obtained that was extremely faithful to the original image. It showed excellent printing durability.

Claims (1)

[Claims] 1. A photoconductive emulsion in which a phthalocyanine photoconductor element and a sensitizer are dispersed in a binder resin solution is coated with an aluminum foil using a gravure cylinder with a plate depth of 30 to 100 microns. 1. A method for producing an electrophotographic photoreceptor, which comprises applying the film onto a composite conductive support layered with a polyester film and drying it. 2. A method for producing an electrophotographic photoreceptor according to claim 1, wherein copper phthalocyanine is used as the phthalocyanine photoconductor element. 3. The method for producing an electrophotographic photoreceptor according to claim 1 or 2, wherein 2.4.7 trinitro-9-fluorenone is used as a sensitizer. 4 As a sensitizer 2.4, 5, 7. Tetranitro-9-
A method for producing an electrophotographic photoreceptor according to claim 1 or 2, using fluorenone.