JP2833170B2 - Manufacturing method of electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an electrophotographic photosensitive member using titanyl phthalocyanine as a charge generation layer.

(Prior Art) Conventionally, inorganic compounds such as selenium, cadmium sulfide, and zinc oxide and organic compounds represented by polyvinyl carbazole have been proposed as photoconductive materials constituting a photosensitive layer of an electrophotographic photoreceptor. It has been put to practical use.

In recent years, electrophotographic non-impact printers using lasers and LEDs as light sources have been widely used, and the use of electrophotographic photosensitive members has been expanding. In particular, when a laser is used as a light source, a semiconductor laser is often used because of its advantages such as small size and low cost.
A photoreceptor having a near-infrared region of 30 nm and having high photosensitivity to this wavelength region is required.

Organic photoconductive materials that meet this requirement include squarylium-based pigments, triphenylamine-based trisazo pigments,
Although phthalocyanine-based pigments and the like are known, as a photoreceptor for a semiconductor laser, not only that the photosensitive wavelength region extends to a long wavelength, but also that the chargeability is high, the dark decay is small, and the residual potential is small. In addition, the organic photoconductive material is not always satisfactory because durability such as stability of charging potential upon repeated use is required.

Photosensitivity improving techniques for extending the photosensitive wavelength range of phthalocyanine pigments to longer wavelengths are reported, for example, in JP-A-59-166959 and JP-A-1-120564.

JP-A-59-166959 discloses that a titanyl phthalocyanine vapor-deposited film is brought into contact with saturated vapor of tetrahydrofuran for 1 to 24 hours to have a specific infrared absorption spectrum and a crystal structure having an X-ray diffraction spectrum, It is described that when this deposited film is used as a charge generation layer, a photoreceptor having high photosensitivity in a wavelength region of 750 nm or more can be obtained.

Further, JP-A-1-120564 discloses that a titanyl phthalocyanine vapor-deposited film is immersed in alcohol for 1 to 10 seconds to have a crystal structure having a specific X-ray diffraction spectrum. It is disclosed that a photoreceptor having high sensitivity and excellent electrophotographic photosensitive characteristics can be obtained in the electron wavelength region of 600 to 800 nm by using.

Among the known techniques, the former has an X-ray diffraction spectrum completely different from that of the titanyl phthalocyanine vapor-deposited film of the present invention in its crystal structure. Furthermore, it is necessary to contact the titanyl phthalocyanine vapor-deposited film with the solvent vapor for one hour or more. In order to improve the productivity, when synchronizing the titanyl phthalocyanine vapor deposition step and the charge transport layer coating step, the solvent vapor treatment is required. Large-scale equipment is required, which is not preferable for mass production.

In the latter, the titanyl phthalocyanine vapor-deposited film is 1 to
By immersing in alcohol for 10 seconds, the crystal structure is changed, but in fact, after immersion in alcohol, before the application of the charge transport layer, the alcohol must be dried. Requires drying time,
Further, in the case of forced drying, a place and equipment such as a dryer for the forced drying are required, which is not preferable.

The present invention has been made in view of the above-described problems in the related art. Accordingly, an object of the present invention is to provide a novel method for producing a novel electrophotographic photoreceptor having high photosensitivity to the near infrared wavelength region of a semiconductor laser, excellent durability, and high productivity. .

(Means for Solving the Problems) The present invention relates to a method for producing an electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer provided on a conductive support, wherein titanyl phthalocyanine is deposited to form a deposition layer. Forming, and then contacting the deposited layer with a mixed vapor containing at least an aromatic solvent and water to form a crystal structure showing a diffraction peak at a black angle (2θ ± 0.2 °) 27.3 ° in an X-ray diffraction spectrum. And forming a charge generation layer made of titanyl phthalocyanine.

 Hereinafter, the present invention will be described in detail.

FIG. 1 and FIG. 2 are schematic configuration diagrams showing an example of the configuration of an electrophotographic photosensitive member manufactured according to the present invention. First
In the figure, the laminate has a layered structure in which at least a charge generation layer 2 and a charge transport layer 3 are provided on a conductive support 1, and in FIG. An undercoat layer 4 is provided.

 First, a method for forming the charge generation layer will be described.

In order to form the charge generation layer, first, titanyl phthalocyanine is vapor-deposited on the conductive support directly or through an undercoat layer.

Titanyl phthalocyanine used for vapor deposition may be obtained by any of the methods such as those obtained by a general synthesis method, or those obtained by purifying it by an acid paste method, a sublimation purification method, or the like, Its crystal structure may be any.

Vacuum is deposited at a degree of vacuum of 10 ^-4 to 10 ^-7 Torr and a deposition source temperature of 350 to 600.
C., preferably 450 to 500.degree. C., and a substrate temperature of 20 to 100.degree. C., preferably 20 to 50.degree. In particular, since the substrate temperature slightly affects the crystallinity of the titanyl phthalocyanine film after vapor deposition, it is preferable to set the temperature as low as possible.In the present invention, the above temperature range can be adopted. .

The formed titanyl phthalocyanine vapor-deposited film is preferably an amorphous film, and has a thickness of 100 to 5 mm.
000 °, preferably in the range of 300 ° to 2000 °. When the film thickness is less than 100 mm, the photosensitivity is reduced due to a decrease in the light absorption of the formed charge generation layer, and when the film thickness is more than 5000 mm, the heat generation carriers in the charge generation layer increase due to the increase. , As dark decay increases and chargeability decreases,
It is preferable to set the above range.

Next, the vapor-deposited film formed as described above is treated with a mixed vapor containing at least aromatic and water. The vapor pressure ratio between the aromatic solvent and water in the mixed steam can be controlled by the processing temperature, and the processing conditions vary depending on the aromatic solvent used, but the processing temperature ranges from 30 ° C to 100 ° C.
C., preferably 50 to 80.degree. C., use time 1 to 10 minutes, preferably 3 to 5 minutes.

In the present invention, as the aromatic solvent used to constitute the mixed vapor, specifically, benzene, toluene,
Xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene and the like can be mentioned. The mixed vapor may further contain an aromatic solvent and another solvent constituting a ternary azeotrope with water. Such solvents include, for example, benzene and water, or toluene and water,
Examples include ethanol and isopronol. When these other solvents are contained, the mixing ratio and the processing temperature are preferably the composition ratio and the azeotropic temperature so as to constitute a ternary azeotropic mixture.

As a method of bringing the mixed vapor into contact with the titanyl phthalocyanine vapor-deposited film, for example, a closed container or an open container is filled with a solvent component constituting the mixed vapor, and the entire container is heated to generate the mixed vapor. A method in which a titanyl phthalocyanine vapor film is held in the container for a predetermined time, or a method in which a mixed vapor generated in a closed container is guided by a pipe and sprayed from a slit, a nozzle, or a perforated plate onto the titanyl phthalocyanine vapor-deposited film. Although it can be mentioned, of course, it is not limited to these methods.

By performing the treatment as described above, titanyl phthalocyanine forming a vapor-deposited film has a crystal structure showing a diffraction peak at a black angle (2θ ± 0.2 °) 27.3 ° in an X-ray diffraction spectrum.

Next, a method for forming the charge transport layer will be described.
The charge transport layer is formed by applying a coating solution obtained by dissolving a charge transport material and a binder resin in an organic solvent onto the charge generation layer. The compounding ratio of the charge transport material and the binder resin in the coating solution is usually set in the range of 5: 1 to 1: 5.

Examples of the charge transport material include polycyclic aromatic compounds such as anthracene, pyrene, and phenanthrene; compounds having a nitrogen-containing heterocycle such as indole, carbazole and imidazole; pyrazoline compounds; hydrazone compounds; triphenylmethane compounds; and triphenylamine. Compound,
Any known compounds such as an enamine compound and a stilbene compound can be used. Further, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylanthracene, poly-N
-Photoconductive polymers such as vinylphenylanthracene, polyvinylpyrene, polyvinylacridine, polyvinylacenaphthylene, polyglycidylcarbazole, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, etc., which themselves form the charge transport layer May be.

The binder resin can be selected from a wide range of insulating resins. Preferred binder resins include polyvinyl butyral, polyarylate, polycarbonate, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulose resin, and urethane resin. And insulating resins such as epoxy resin, casein, polyvinyl alcohol and polyvinyl pyrrolidone.

As the organic solvent, specifically, methanol, ethanol, alcohols such as isopropanol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone,
N, N-dimethylformamide, amides such as N, N-dimethylacetamide, dimethylsulfoxides, tetrahydrofuran, dioxane, ethers such as ethylene glycol monomethyl ether, methyl acetate, esters such as ethyl acetate, chloroform, methylene chloride, Aliphatic halogenated hydrocarbons such as dichloroethylene, carbon tetrachloride, and trichloroethylene, and aromatic hydrocarbons such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene can be used.

Use various methods such as dip coating, spray coating, spin coating, bead coating, wire bar coating, blade coating, roller coating, extrusion coating, curtain coating, etc. Can be. In addition, drying, after touch drying at room temperature,
Heat drying is preferred. Heat drying is 30-200 ℃
At a temperature of 5 minutes to 2 hours at a stationary temperature or under blowing. The thickness of the charge transport layer is usually 5 to
It is set to about 50 μm.

As the electroconductive support, any known electrophotographic photoconductor can be used.

In the present invention, an undercoat layer may be provided on the conductive support as shown in FIG. The undercoat layer is effective for preventing unnecessary charge injection from the conductive support, and has an effect of increasing the chargeability of the photosensitive layer. further,
It also has the effect of increasing the adhesion between the photosensitive layer and the conductive support.
Examples of the material constituting the undercoat layer include polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl pyridine, cellulose esters, cellulose ethers, polyamide, polyurethane, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, Examples include polyacrylamide, zirconium chelate compounds, zirconium alkoxide compounds, organic zirconium compounds, titanyl chelate compounds, titanyl alkoxide compounds, organic titanyl compounds, silane coupling agents, and the like. The thickness of the undercoat layer is 0.05 to 0.5
It is preferable to set to about μm.

(Examples) Hereinafter, the present invention will be described specifically with reference to examples.

Example 1 A titanyl phthalocyanine pigment having an X-ray diffraction spectrum shown in FIG. 3 was prepared by applying a vacuum of 10 ^-5 Torr and an evaporation source temperature of 450 ° C.
Then, the film was deposited on an aluminum substrate so as to have a film thickness of 500 ° C., and left in a mixed vapor of monochlorobenzene and water heated to 50 ° C. for 3 minutes to form a charge generation layer. FIG. 4 shows the X-ray spectrum of this charge generation layer.

Next, the following structural formula And 2 parts of a compound represented by the following structural formula 3 parts of poly (4,4-cyclohexylidenediphenylene carbonate) is dissolved in 20 parts of monochlorobenzene, and the obtained coating solution is applied on an aluminum substrate on which a charge generation layer is formed by dip coating. After air drying, heat and dry at 100 ° C for 1 hour.
A μm charge transport layer was formed.

The obtained electrophotographic photoreceptor is subjected to normal temperature and normal humidity (20 ° C, 50% R
In the environment of H), a -6 KV corona discharge was applied for 2 seconds using an electrostatic copying paper tester (EPA-8100, manufactured by Kawaguchi Electric Co., Ltd.), and then the light of the tungsten lamp was changed to a monochromator. Into monochromatic light of 790 nm by using
Irradiation was adjusted to μW / cm ² . The exposure amount E _1/2 (erg / cm) until the surface potential becomes 1/2 of the initial potential V _0.
² ) Measure, then apply 10 lux tungsten light to 1
Irradiating the second photoreceptor surface was measured residual potential V _R. Further, V ₀ , E after repeating the above charging and exposure 1000 times.
It was measured _1/2 and V _R. Table 1 shows the obtained results.

Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the deposited film was treated in a mixed vapor of toluene and water heated at 50 ° C. for 5 minutes. FIG. 5 shows an X-ray diffraction spectrum of the charge generation layer of the electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 As a method for treating a deposited film, toluene heated to 74 ° C.
An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the photosensitive member was left in a mixed vapor of water and ethanol for 3 minutes. FIG. 6 shows an X-ray diffraction spectrum of the charge generation layer of the electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4 Type 8 nylon (trade name:
Lacamide 5003, manufactured by Dainippon Ink Co., Ltd.), 5 parts, methanol 3 parts, n-butanol 2 parts by a dip coating method, and dried by heating at 150 ° C. for 5 minutes. An undercoat layer of μm was formed.

Next, a charge generation layer and a charge transport layer were formed on the undercoat layer in the same manner as in Example 1. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5 An electrophotographic photoreceptor was produced in the same manner as in Example 4 except that the thickness of the charge generation layer was changed to 1000 °, and evaluation was conducted in the same manner as in Example 1. The results are shown in Table 1.

Example 6 An organic zirconium compound (trade name: Organix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) 10 was placed on an aluminum substrate.
Parts, silane coupling agent (trade name: A1110, manufactured by Nippon Unicar Co., Ltd.) 11 parts, ethanol 5 parts, n-butanol 2
Using a coating solution consisting of parts, apply by dip coating, and heat dry at 150 ° C for 5 minutes to a film thickness of 0.1 μm
Was formed.

Next, on this undercoat layer, in the same manner as in Example 1,
A charge generation layer and a charge transport layer were formed. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the treatment in a mixed vapor of monochlorobenzene and water was not performed. FIG. 7 shows an X-ray diffraction spectrum of the charge generation layer of the electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 4, except that the treatment in a mixed vapor of monochlorobenzene and water was not performed, and the same evaluation was performed. Was. The results are shown in Table 1.

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the deposited film was left in monochlorobenzene vapor heated at 50 ° C. for 3 minutes. FIG. 8 shows an X-ray diffraction spectrum of the charge generation layer of the electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the deposited film was left in toluene vapor heated at 50 ° C. for 5 minutes. FIG. 9 shows an X-ray diffraction spectrum of the charge generation layer of the electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 5 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the deposited film was left in steam heated to 50 ° C. for 5 minutes. The obtained electrophotographic photosensitive member was evaluated in the same manner as in Example 1. First result
It is shown in the table.

According to these results, any electrophotographic photoreceptor having a charge generation layer formed of a titanyl phthalocyanine vapor-deposited film treated with a mixed vapor of an aromatic solvent and water according to the present invention was untreated or did not undergo treatment. It can be seen that the chargeability, the photosensitivity, and the stability upon repeated use are better than those treated with a single vapor of a group solvent or steam.

(Effects of the Invention) According to the method of the present invention, it is possible to convert a titanyl phthalocyanine vapor-deposited film into a film having a specific crystal structure by a simple treatment, and to have a crystal structure converted in such a manner. An electrophotographic photosensitive member having a charge generation layer made of titanyl phthalocyanine has extremely high sensitivity to the near-infrared wavelength region of a semiconductor laser and has excellent durability. Therefore, the present invention is extremely useful for manufacturing an electrophotographic photosensitive member for a semiconductor laser.

[Brief description of the drawings]

1 and 2 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention, respectively. FIG. 3 is an X-ray diffraction diagram of a titanyl phthalocyanine pigment used for vapor deposition in Examples, and FIGS. And FIG. 6 are X-ray diffraction diagrams of the charge generation layers of the electrophotographic photosensitive members of Examples 1, 2 and 3, respectively. FIGS. 7, 8 and 9 are Comparative Examples 1, 3 and 4, respectively. 3 shows an X-ray diffraction diagram of the charge generation layer of the electrophotographic photoreceptor of FIG. 1 ... conductive support, 2 ... charge generation layer, 3 ... charge transport layer, 4 ... undercoat layer.

Claims (1)

(57) [Claims] 1. A method for producing an electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer provided on a conductive support, wherein titanyl phthalocyanine is vapor-deposited to form a vapor-deposited layer. A charge generation layer comprising titanyl phthalocyanine having a crystal structure showing a diffraction peak at a black angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by being brought into contact with a mixed vapor containing at least an aromatic solvent and water. Forming an electrophotographic photosensitive member.