JPH03100659A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and to reduce residual potential and to stabilize potential characteristics even at the time of repeated uses by incorporating specified titanyl-phthalocyanine. CONSTITUTION:The photosensitive layer contains the titanyl-phthalocyanine having peaks at the Bragg angles 2 theta of 6.8 deg., 14.9 deg., 24.8 deg., and 26.2 deg. in the diffraction pattern with respect to the CU-Kalpha characteristic X-ray. The fundamental structure of the titanyl-phthalocyanine is represented by formula I in which each of X<1>-X<4> is H, halogen, alkyl, alkoxy, and each of n, m, l, and k is an integer of 0-4, thus permitting potential acceptance to be good, sensitivity, and potential stability at the time of repeated uses to be enhanced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, which can be particularly effectively used in printers, copiers, etc., and is highly resistant to semiconductor laser light and LED light. The present invention relates to an electrophotographic photoreceptor exhibiting sensitivity.

[Conventional technology]

Conventionally, inorganic photoreceptors provided with a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component have been widely used as electrophotographic photoreceptors. However, such inorganic photoreceptors do not always satisfy the characteristics such as photosensitivity, thermal stability, moisture resistance, and durability required of electrophotographic photoreceptors for copying machines and the like. For example, selenium crystallizes due to heat, fingerprint stains, etc., so its properties as an electrophotographic photoreceptor tend to deteriorate.

In addition, electrophotographic photoreceptors using cadmium sulfide are moisture resistant,
Durability is poor, and electrophotographic photoreceptors using zinc oxide also have durability problems. Electrophotographic photoreceptors made of selenium or cadmium sulfide also have the drawback of severe restrictions in manufacturing and handling due to toxicity.

In order to improve the drawbacks of such inorganic photoconductive materials,
Attempts have been made to use various organic photoconductive substances in photosensitive layers of electrophotographic photoreceptors, and research has been actively conducted in recent years. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing polyvinylcarbazole and trinitrofluorenone. However, this photoreceptor does not have sufficient sensitivity and durability. Therefore, a functionally separated electrophotographic photoreceptor has been developed in which the carrier generation function and the carrier transport function are assigned to different substances. In such electrophotographic photoreceptors, materials can be selected from a wide range, so
It is expected that organic photoreceptors with arbitrary characteristics can be easily obtained, and therefore have high sensitivity and excellent durability.

Various organic dyes and organic pigments have been proposed as carrier-generating substances for such electrophotographic photoreceptors with functionally separated pots, including polycyclic quinone compounds typified by dibromuanthurone, pyrylium compounds, pyrylium compounds, and polycarbonates. Co-crystal complexes, squalium compounds, phthalocyanine compounds, azo compounds, etc., have been put into practical use.

Among these, phthalocyanine compounds, which are one of the organic photoconductive materials, are known to have a photosensitive range extending to longer wavelengths than other compounds.

Particularly in recent years, titanyl phthalocyanine has attracted attention.
The titanyl phthalocyanine described in No. 7 has a CuKa of 1.5.
Bragg angle 2θ for 41 people; 7. θ°, 15.5
It has clear peaks at 23.4° and 23.4°. However, these titanyl phthalocyanines have problems such as poor dispersibility and poor chargeability and potential stability for repeated use.

[Problem that the invention seeks to solve]

However, many of the carrier-generating substances mentioned above have their main sensitivity range in the short wavelength region or middle wavelength region of visible light, and their use in photoreceptors for laser printers using semiconductor laser light sources is limited by their oscillation wavelengths. The area is 750n
Sensitivity in the wavelength range from m to 850 nm was often insufficient. Among these, certain azo compounds and certain phthalocyanine compounds have been found to have main sensitivity in the long wavelength region of 750 nm or more, but all of these compounds have a specific aggregate structure or a specific crystal structure. By increasing the wavelength of the compound, the main absorption is made to have a longer wavelength, and at the same time, the ability to generate carriers is increased. Therefore, consideration of the manufacturing conditions of the compound and the manufacturing conditions of the photoreceptor has become an important issue. Due to the complexity of such technology, charging ability,
At present, no electrophotographic photoreceptor has been found that is satisfactory in overall sensitivity, repeatability, etc., and there is currently a need to develop a high-performance electrophotographic photoreceptor.

[Purpose of the invention]

The purpose of the present invention is to achieve high sensitivity and low residual potential.
Another object of the present invention is to provide an excellent electrophotographic photoreceptor whose potential characteristics are stable even after repeated use.

Another object of the present invention is to provide an electrophotographic photoreceptor having sufficient sensitivity even to long wavelength light sources such as semiconductor lasers.

[Structure and effects of the invention]

The above object of the present invention is to obtain Bragg angles 2θ of 6.8″, 14.9°, 24.8°, 26 in the diffraction pattern for Cu-Ka characteristic X-ray (wavelength 1.541).
．． This can be achieved by incorporating titanyl phthalocyanine having a peak at 2° into the photosensitive layer.

The basic structure of the titanyl phthalocyanine of the present invention is represented by the following general formula.

In the general formula, X 1 , X 3 , and X 4 represent a hydrogen atom, a hydrogen atom, an alkyl group, or an alkoxy group, and n, m, 12. represents an integer from 0 to 4.

The X-ray diffraction spectrum is measured under the following conditions, and the peak here refers to a distinct acute-angled protrusion that is different from noise. Note that the peak position varies by about ±0.2' depending on the condition of the sample or due to measurement error, but the error value will not be described in the description of the present invention.

X-ray tube Cu voltage 40. OKV current
100 mA start angle 6. Od
eg.

Stop angle 35. Odeg.

Step angle 0.02 deg.

Measurement time: 0.50 sec.

The titanyl phthalocyanine of the present invention can be obtained, for example, by reacting 1°3-diiminoisoindoline with a titanium coupling agent.

In the present invention, other carrier-generating substances may be used in combination with the above titanyl phthalocyanine. Such a carrier generating substance differs in crystal form from the titanyl phthalocyanine of the present invention. Examples include titanyl phthalocyanine of a type, β, σβ mixed type, and amorphous type, as well as other phthalocyanine pigments, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, and squareium pigments.

Various carrier transport substances can be used in the photoreceptor of the present invention, but representative examples include nitrogen-containing heterocyclic nuclei represented by oxazole, oxadiazole, thiazole, thiadiazole, imidazole, etc. Compounds having such condensed ring nuclei, polyarylalkane compounds, pyrazoline compounds, hydrazone compounds, triarylamine compounds, styryl compounds, styryltriphenylamine compounds, β-7enylstyryltriphenylamine compounds , butadiene compounds, hexatriene compounds, carbazole compounds, condensed polycyclic compounds, and the like. Specific examples of these carrier transport substances include, for example, JP-A-61-10
The carrier transport substances described in No. 7356 can be cited, and the structures of particularly typical ones are shown below.

(1) Below margin (2) (6) (3) (7) (4) (8) (5) (9) (lO) (14) (11) (15) (12) (16) (13) (17) zH6 (18) (19) Various configurations of photoreceptors are known. Although the photoreceptor of the present invention can take any of these forms, it is preferably a layered or dispersed functionally separated photoreceptor.

In this case, the configuration is usually as shown in FIGS. 1 to 6. The layer structure shown in FIG. 1 is such that a carrier generation layer 2 is formed on a conductive support l, and a carrier transport layer 3 is laminated thereon to form a photosensitive layer 4. Photosensitive layer 4' with carrier generation layer 2 and carrier transport layer 3 reversed
was formed. 3 shows an intermediate layer 5 provided between the photosensitive layer 4 and the conductive support 1 having the layer structure shown in FIG. 1, and FIG. 4 shows the photosensitive layer 4' and the conductive support 1 having the layer structure shown in FIG. An intermediate layer 5 is provided between the two. The layer structure shown in FIG. 5 is a photosensitive layer 4 containing a carrier-generating substance 6 and a carrier-transporting substance 7.
'', and FIG. 6 shows such a photosensitive layer 4.
An intermediate layer 5 is provided between the conductive support l and the conductive support l.

In forming the photosensitive layer, it is effective to apply a solution in which a carrier-generating substance or a carrier-transporting substance is dissolved alone or together with a binder or an additive. However, because the solubility of carrier-generating substances is generally low,
In such a case, it is effective to apply a solution in which fine particles of a carrier-generating substance are dispersed in a suitable dispersion medium using a dispersion device such as an ultrasonic dispersion machine, a ball mill, a sand mill, or a homomixer. In this case, the binder and additives are usually added to the dispersion.

A wide variety of solvents or dispersion media can be used to form the photosensitive layer. For example, butylamine, ethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone,
Examples include tetrahydrofuran, dioxane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, toluene, xylene, acetophenone, chloroform, dichloromethane, dichloroethane, trichloroethane, methanol, ethanol, chloronol, butanol, and the like.

When a binder is used to form a carrier generation layer or a carrier transport layer, any binder can be selected as the binder, but a hydrophobic polymer having film-forming ability is particularly desirable.

Examples of such polymers include, but are not limited to, the following:

Polycarbonate Polycarbonate Z Resin Acrylic Resin Methacrylic Resin Polyvinyl Chloride Polyvinylidene Chloride Polystyrene
Styrene-butadiene copolymer polyvinyl acetate polyvinyl formal polyvinyl butyral polyvinyl acetal polyvinyl carbazole styrene-alkyd resin silicone resin
Silicone-alkyd resin polyester
Phenolic resin Polyurethane Epoxy resin Vinylidene chloride-acrylonitrile copolymer Vinyl chloride-vinyl acetate copolymer Vinyl chloride-vinyl acetate-maleic anhydride copolymer The ratio of carrier-generating substance to the binder is 10 to 600%
is desirable, and more preferably 50 to 400 wt%.

The ratio of carrier transport substance to binder is lO ~ 50
It is desirable to set it to 0vt%. The thickness of the carrier generation layer is 0.01 to 20 pm, more preferably 0.05 to 5 pm.
μm is preferred. The thickness of the carrier transport layer is 1-100μ
Although the thickness is I, 5 to 30 μm is more preferable.

The photosensitive layer may contain an electron-accepting substance for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use. Examples of such electron-accepting substances include succinic anhydride, maleic anhydride, dibromo succinic anhydride, phthalic anhydride, tetrachloro-7-thalic anhydride, tetrabromo-7-thalic anhydride, 3-nitro-phthalic anhydride, and 4-nitro-phthalic anhydride. Phthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, ■-dinitrobenzene, 113I5-trinitrobenzene, p-nitrobenzonitrile, vicryl chloride, quinone chloride Imide, chloranil, chloranil, dichlordicyano-p-benzoquinone, anthraquinone, dinitroanthraquinone, 9-fluorenylidenemalonodinitrile, polynitro-9-fluorenylidenemalonodinitrile, picric acid, o-nitrobenzoic acid, p- Nitrobenzoic acid, 3,5-
Examples include dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, heptatalic acid, mellitic acid, and other compounds with high electron affinity. The addition ratio of the electron-accepting substance is 0.00 to 100 by weight of the carrier-generating substance. O1-200 is desirable, and 0.1-100 is more preferable.

Further, the photosensitive layer may contain deterioration inhibitors such as antioxidants and light stabilizers for the purpose of improving storage stability, durability, and environmental dependence resistance. Compounds used for such purposes include, for example, chromanosif 114 compounds such as tocopherol and rJso(7) etherified or esterified compounds, polyarylalkane compounds, hydroquinone derivatives and their mono- and di-etherified compounds, benzophenone derivatives, and benzophenone derivatives. Triazole derivatives, thioether compounds, phosphonic acid esters, phosphorous acid esters, phenylenediamine derivatives, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like are effective. Specific examples of particularly effective compounds: Toshiteha, rlRGA
NOX l0IOJ, rlRGANOX565J
(manufactured by Ciba Geigy), "Sumilizer BHT"
, "Hindered phenol compounds such as Sumilizer IJDPJ (manufactured by Sumitomo Chemical Co., Ltd.)," Sanol LS-26
Examples include hindered amine compounds such as Sanol LS-622LDJ and Sanol LS-622LDJ (manufactured by Sankyo Co., Ltd.). middle class,
As the binder used for the protective layer etc., those listed above for the carrier generation layer and the carrier transport layer can be used, but in addition, polyamide resin, nylon resin, ethylene-vinyl acetate copolymer, ethylene-acetic acid Vinyl-maleic anhydride copolymer, ethylene-vinyl acetate-
Ethylene resins such as methacrylic acid copolymers, polyvinyl alcohol, cellulose derivatives, etc. are effective.

As the conductive support, a metal plate or a metal drum is used, or a thin layer of a conductive polymer, a conductive compound such as indium oxide, or a metal such as aluminum or flagylum is applied by means such as coating, vapor deposition, or lamination. A material provided on a substrate such as paper or plastic film can be used.

The photoreceptor of the present invention has the above-mentioned structure, and as is clear from the following examples, it has excellent charging characteristics, sensitivity characteristics, and repeatability characteristics.

〔Example〕

(Synthesis Example 1) 29.3 g of 1,3-diiminoisoindoline and 200 m2 of 1-propatool were mixed, and a titanium coupling agent (
83.6 g of BlenAct KR-55 (manufactured by Ajinomoto Co., Ltd.) was added thereto, and the mixture was heated under reflux for 5 hours under a nitrogen stream. After cooling, the precipitate was collected by filtration, washed with chloroform, 2% aqueous hydrochloric acid, water, methanol, and dried to obtain reddish-purple crystals. This crystal has a Bragg angle of 2θ of 6.8° in the X-ray diffraction spectrum.

The titanyl phthalocyanine of the present invention shown in FIG. 7 had peaks at 14.9°, 24.8″, and 26.2°.

(Comparative Synthesis Example 1) 5 g of titanyl phthalocyanine obtained in Synthesis Example 1 was
After dissolving in 150 g of 96% sulfuric acid at 5° C., the solution was filtered through a glass filter, and the resulting sulfuric acid solution was poured into 1500 ml of water, and the precipitated crystals were collected by filtration.

The crystals were washed repeatedly with deionized water until the filtrate was neutral, then treated with pyridine and methanol. The obtained crystal has a bulla-knob angle 2θ of 6.0 mm as shown in FIG.
Peaks were observed at 9°, 15.5°, 23.4°, and 25.5°.

(Example 1) 1 part of titanyl phthalocyanine having the X-ray diffraction pattern shown in FIG. ) and 100 parts of methyl ethyl ketone as a dispersion medium were dispersed using a sand mill, and aluminum was vapor-deposited onto the polyester base using a wire bar to form a film with a film thickness of 0.5 parts.
A 2 μm carrier generation layer was formed. Next, 1 part of the carrier transport substance 1, 1.3 parts of polycarbonate resin "Nipiron Z200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.), and a trace amount of silicone oil rKF-54J (manufactured by Shin-Etsu Chemical Co., Ltd.) were added to 10 parts of 1.2-dichloroethane. The dissolved liquid was applied using a blade coater and after drying, a carrier transport layer having a thickness of 20 μm was formed.The thus obtained photoreceptor is referred to as sample 1.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that the titanyl phthalocyanine shown in FIG. 7 in Example 1 was replaced with the comparative titanyl phthalocyanine having the X-ray diffraction pattern shown in FIG. A photoreceptor for comparison was obtained. This is a comparison sample (
1).

(Evaluation 1) The sample obtained as described above was evaluated as follows using a paper analyzer EPA-8100 (manufactured by Kawaguchi Electric Co., Ltd.). First, corona charging was performed for 5 seconds under the condition of -80 μA, and the surface potential Va immediately after charging was
The surface potential Vi after being left for 5 seconds was determined, and then exposure was performed so that the surface illuminance was 2 lux, and the surface potential was reduced to 1/1.
The exposure amount El/□ is required to set the voltage to 2Vi, and the exposure amount E is required to lower the surface potential from -600V to -100V. . 7. . . I asked for Also D-100 (Va-
The dark decay rate was determined from the formula Vi)/Va(%). The results are shown in Table 1.

(Evaluation 2) The obtained sample was also evaluated using a modified printer LP-3010 (manufactured by Konica) equipped with a semiconductor laser light source. Find the unexposed part potential V□ and the exposed part potential vL,
Furthermore, vH and vL after 10,000 repetitions were determined. The results are shown in Table 2.

Table Example (2) A 0.1 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MF-10J (manufactured by Tsukisui Kagaku Co., Ltd.) was formed on an aluminum drum. On the other hand, 1 part of the titanyl phthalocyanine shown in Figure 7 obtained in Synthesis Example 1 was ground in a ball mill, and then a solution of polycarbonate resin [3 parts of Panlite L-1250J, 15 parts of monochlorobenzene, and 35 parts of 1,2-dichloroethane] was added. Dispersion was performed. To the resulting dispersion, 2 parts of the carrier transport substance (1) was further added, and the mixture was applied onto the intermediate layer by spray coating and dried to a thickness of 20 μm.
A photosensitive layer was formed.

The thus obtained photoreceptor was evaluated in the same manner as in Evaluation 1 except that the charging polarity was changed to positive polarity.

Va -1385 (V) v; -1000 (V) D = 27.8 (%) E ryx -1,61 (1ux-sec) E
@oo /+oo-4・18 (lux es
ec) The titanyl-7-talocyanine used in the present invention has excellent dispersibility, and as is clear from the above examples, the electrophotographic photoreceptor of the present invention has good charging properties, high sensitivity, and stable potential during repeated use. It is clear that the properties are excellent.

[Brief explanation of drawings]

1 to 6 are cross-sectional views showing specific examples of the layer structure of the photoreceptor of the present invention. Figure 7 shows titanyl 7 of the present invention obtained by Synthesis Example 1.
X-ray diffraction diagram of talocyanine. FIG. 8 is an X-ray diffraction diagram of titanyl phthalocyanine obtained in Comparative Synthesis Example 1. l-1--Conductive support 2--111 Carrier generation layer 3--11 Carrier transport layer 4.4°, 4''-111 Photosensitive layer 5-m-Intermediate layer Fig. Figure Figure Figure

Claims (1)

[Claims] In the X-ray diffraction spectrum for Cu-Kα rays (wavelength 1.541 Å), Black angle 2θ is 6.8°, 14.
An electrophotographic photoreceptor comprising titanyl phthalocyanine having peaks at 9°, 24.8°, and 26.2°.