JPH0242216B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor, and provides a novel electrophotographic photoreceptor provided with a photosensitive layer containing an azo compound having a phthalocyanine skeleton. In recent years, the use of electrophotography has expanded not only to the field of copying machines, but also to fields where photographic technology has traditionally been used, such as printing plates, slide films, and microfilms. Application to high-speed printers is also being considered. Accordingly, the requirements for electrophotographic photoreceptors are becoming more sophisticated and wide-ranging. Until now, photoreceptors used in electrophotography have mainly had photosensitive layers containing inorganic conductive substances such as amorphous selenium, cadmium sulfide, and zinc oxide. Although these inorganic photoreceptors are useful, they also have various drawbacks. In recent years, in order to compensate for this, electrophotographic photoreceptors using various organic substances have been proposed and have begun to be put into practical use. Needless to say, the electrophotographic photoreceptor must have a carrier generation function and a carrier transport function. Many pigments have been proposed as organic compounds that can be used as carrier generating substances, including phthalocyanine, polycyclic quinone, indigo, dioxazine, quinacridone, and azo pigments, but only a limited number of them have been put into practical use. It is being
In addition, the range of carrier transfer materials that can be selected is limited, so that at present no material that satisfactorily meets the wide range of requirements of electrophotographic processes has been obtained. The present inventors conducted research to improve organic electrophotographic photoreceptors, and discovered that a photoreceptor provided with a photosensitive layer containing an azo compound having a phthalocyanine skeleton has excellent characteristics, and has arrived at the present invention. The azo compound having a phthalocyanine skeleton used as a material for the photosensitive layer of the electrophotographic photoreceptor in the present invention is represented by the following general formula (). (below,
The metalophthalocyanine moiety is expressed as “MPC” and abbreviated as “MPc〕(---N=N-A) _o .) [In the formula, n is a number from 2 to 4, M is H2 or a divalent metal atom such as Cr, Fe, Co, Ni, Cu, Zn, Pt, Pd, etc., and A is a general formula

【formula】

【formula】

【formula】

【formula】

It is a group represented by [Formula]. In the above formula, Z is an atomic group necessary to form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocycle, and Y is -NR ⁷ R ⁸ , -OR ⁹ or -
NHN=CH− ^R10 . R ¹ and R ² are substituted or unsubstituted alkyl groups, aralkyl groups, aryl groups, or heterocyclic groups, R ³ is an alkyl group or carboxyl group, or an ester thereof, R ⁴ , R ⁵ , R ⁸ and R ¹⁰ is a substituted or unsubstituted aryl group or heterocyclic group, and R ⁶ , R ⁷ and R ⁹ are H, substituted or unsubstituted alkyl group, aralkyl group, aryl group or heterocyclic group. n (-N=N-A) groups are specified in the [MPc] moiety.

[Formula] may have two or more, or each

[Formula] may have one each. ] The electrophotographic photoreceptor of the present invention has the excellent carrier generation function of the above-mentioned [MPc](--N=N-A) _o as a carrier of a so-called laminated or dispersion type electrophotographic photoreceptor. By using it as a generating substance, it not only has excellent electrophotographic properties such as charging characteristics, charge retention, sensitivity, and residual potential, but also has good film properties, less deterioration due to repeated use, and is resistant to heat, humidity, and light. It is a photoreceptor that exhibits stable performance without any changes in its properties. Specific examples of compounds having the structure [MPc](--N=NA) _o are listed below. First, a typical example when "-A" is the above general formula (a) is: There are the following compounds.

【table】

【table】

【table】

【table】

【table】

【table】 \
｜R ⁶
COCH ₃
If so, we have the following compound.

[Table] Cifenil
The above compounds can be synthesized by known methods.
(For example, FHMoser et al. “Phthalocyanine
Compounds”, Reinhold Publishing Co., New
York, 1963 p.248, and Tokuko Sho 39-16632)

[Formula] The starting material is one in which one amino group has been introduced in advance, and by forming the [MPc] moiety and diazotizing it, four

[Formula] A target compound in which one (-N=N-A) is substituted for each is obtained. The physical configuration of the electrophotographic photoreceptor of the present invention may be in any known form. On a conductive support, a carrier generating layer containing the above-mentioned [MPc] (---N=NA) _o compound as a carrier generating substance as a main component, and a carrier transport layer containing a carrier transporting substance as a main component. Alternatively, a photosensitive layer in which a carrier-generating substance is dispersed in a carrier-transporting substance may be provided. Since these may be provided through an intermediate layer, the following pattern is possible. Support / Carrier generating layer / Carrier transport layer Support / Carrier transport layer / Carrier generating layer support / Carrier transport layer containing a carrier generating substance Support / Intermediate layer / Carrier generating layer / Carrier transport layer Support / Intermediate layer / Carrier transport layer/carrier generation layer Support/intermediate layer/carrier transport layer containing a carrier-generating substance Carrier transport substances include those that transport electrons and those that transport holes. Either can be used to form. The electrophotographic photoreceptor of the present invention can be manufactured in a conventional manner according to techniques known in the manufacture of photoreceptors using organic photoconductive materials. For example, the carrier generation layer forming the two-layered photosensitive layer is prepared by forming the above-mentioned [MPc] (---N=N-A) _o compound into fine particles in a suitable medium, and adding a binder as necessary. , either directly onto the conductive support or via an interlayer, or onto an already formed carrier transport layer and dried. Fine particles in the medium have a diameter of 5μ or less, preferably
It is necessary to disperse the particles at a particle size of 3μ or less, optimally 1μ or less. When using a binder, there is no particular limitation, but a hydrophobic, high dielectric constant, electrically insulating film-forming polymer compound is preferred. Various thermoplastic or thermosetting synthetic resins can be suitably used. As will be readily understood, it is advantageous for the medium to have the ability to dissolve the binder. The amount of the binder to be used is selected from a range of 0.1 to 5 times the weight of the carrier generating compound. The thickness of the carrier generation layer is in the range of 0.01 to 20μ. Preferably it is 0.05-5μ. The carrier transport layer can be formed by dissolving a carrier transport material in a suitable medium, applying the solution, and drying. As the medium, those used for preparing a dispersion of the carrier generation layer can be used. It is preferred to use a binder, unless the carrier transport material is one that also acts as a binder itself, such as poly N-vinyl carbazole or polyglycidyl carbazole.
As the binder, the same binder used for forming the carrier generation layer can be used. The amount of binder used depends on the amount of carrier transport material.
0.2 to 5 times the weight is appropriate. The thickness of the carrier transport layer is in the range of 1 to 100 microns, preferably 5 to 50 microns. On the other hand, in order to form a dispersed carrier generation-carrier transport layer, a carrier transport substance may be dissolved or dispersed in the above-mentioned dispersion liquid for forming a carrier generation layer, and the resultant solution may be applied onto a conductive support. Although the carrier transport material is optional, it is generally preferred to add a binder, except when using one that itself serves as a binder, as described above. The amount of binder used is usually 5 to 10 times the weight of the carrier generating material,
The amount of the carrier transport material used is 0.1 to 2.0 times, preferably 0.2 to 1.5 times the weight of the binder. When using a carrier transport material which itself has the ability to act as a binder, the amount is 5 to 10 times the weight of the carrier generating material. When an intermediate layer is provided between the conductive support and the above laminated or dispersed photosensitive layer, the intermediate layer includes:
Conventional materials can be used, including those that serve as binders for the photosensitive layer. The film thickness is preferably 1μ or less. Other known techniques can be applied to the electrophotographic photoreceptor of the present invention. For example, the photosensitive layer may contain a sensitizer. Suitable sensitizers include Lewis acids and dyes that form charge transfer complexes with organic photoconductive substances. Furthermore, a plasticizer may be added to improve the film formability, flexibility, and mechanical strength of the photosensitive layer. As is clear from the following examples, the electrophotographic photoreceptor of the present invention has excellent charging characteristics, sensitivity characteristics, and image forming properties, and has good photosensitivity. There is little variation in charging characteristics and little optical fatigue. It is also highly weather resistant. In the following examples, "parts" represent parts by weight. Example 1 One part of the exemplified compound 1) (n=3, M=Cu, Y=anilino) was placed in 50 parts of tetrahydrofuran and thoroughly dispersed using a ball mill, and the dispersion was applied onto an aluminum plate using a wire coater. , with hot air at 120℃
After drying for 30 minutes, a carrier generation layer having a thickness of about 0.3 μm was provided. On top of that, 5 parts of p-diethylaminobenzaldehyde-N-phenyl-N-benzylhydrazone and 5 parts of polycarbonate resin (Teijin Kasei "Panlite L-1250") were added to 70 parts of 1,2-dichloroethane.
The dissolved solution was applied to the film and dried with hot air at 80° C. for 1 hour to form a carrier transport layer with a thickness of 14 μm. The photoreceptor manufactured in this way was heated at 25℃ and RH.
(Relative humidity) After leaving it in an atmosphere of 55% to adjust the humidity, use the electrostatic paper tester (Kawaguchi Electric Manufacturing Co., Ltd. "SP-
428'') using a static method to perform corona charging at a voltage of -6 KV, and after keeping it in a dark place for 10 seconds, it was exposed to light using a tungsten lamp as a light source so that the sample surface illuminance was 20 lux, and the electrophotographic characteristics were determined. We conducted an evaluation. The following results were obtained. V ₀ (initial charging voltage) = -950 (V) V _D10 (potential retention rate for 10 seconds in the dark) = 87.0 (%) E _1/2 (half-attenuation exposure) = 9.0 (lux seconds) Example 2 A photoreceptor was produced in the same manner as in Example 1 except that exemplified compound 1) with n=2 was used,
The characteristics were measured in the same manner as in Example 1, and the results were as follows. V ₀ = -980 (V) V _D10 = 87.5 (%) E _1/2 10.5 (lux/sec) Example 3 5 parts of exemplified compound 2) (n = 4, M = Cu, Y = 4-chloroanilino) 1 part of polyester resin (Toyobo "Vylon 200") was placed in 250 parts of 1,2-dichloroethane and dispersed using a ball mill.The dispersion was applied onto a polyester film coated with aluminum and heated with hot air at 120℃ for 30 minutes. Dry,
A carrier generation layer with a film thickness of approximately 0.5μ was provided. On top of that, 10 parts by weight of a hydrazone derivative having the following structure, A solution of 10 parts by weight of polyester resin (the above-mentioned "Vylon 200") dissolved in 100 parts by weight of 1,2-dichloroethane is applied and dried with hot air at 100°C for 30 minutes to form a carrier transport layer with a film thickness of 15μ. did. The characteristics of this photoreceptor were measured and the following results were obtained. V ₀ = -1020 (V) V _D10 = 89.0 (%) E _1/2 = 7.5 (lux seconds) Examples 4 to 12 The following exemplified compounds were used in place of exemplified compound 2) in Example 3, A photoreceptor was manufactured in the same manner as in Example 3 except for the above. The characteristics of each are as follows.

【table】

[Table] Example 13 Charge-discharge of the photoreceptor manufactured in Example 5 was measured at 1000
We repeated the experiment and examined the changes in characteristics. The results are as follows, and it was found that the repeatability was excellent.

[Table] Example 14 A film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer (Sekisui Chemical "Eslec MF-10") with a thickness of 0.02μ was placed on an aluminum laminated polyester film (aluminum foil thickness of 10μ). Create an intermediate layer of
On top of that, 1 part of Exemplified Compound 29) (n=2) was added in 1 part,
A dispersion prepared by dispersing an attritor in 50 parts of 4-dioxane was applied and dried with hot air at 100° C. for 30 minutes to form a carrier generation layer with a thickness of 0.2 μm. On top of that, 1,2- Apply a solution dissolved in 100 parts of dichloroethane,
It was dried with hot air at 100°C for 30 minutes to form a carrier transport layer with a thickness of 10μ. When the E _1/2 of the photoreceptor thus obtained was measured,
It was 5.9 lux・sec. This photoreceptor was charged with -7KV corona discharge in a dark place, exposed imagewise at a maximum light intensity of 30 lux/second, developed using a magnetic brush method, and then transferred. As a result, the contrast was strong and the gradation was fine. A good clear image was obtained. Even after repeating the copying test 2000 times, the image remained good and no changes were observed.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor, characterized in that a photosensitive layer containing an azo compound having a phthalocyanine skeleton represented by the following general formula () is provided on a conductive support. [Wherein, n is a number from 2 to 4, M is H2 or a divalent metal atom such as Cr, Fe, Co, Ni, Cu, Zn, Pt, Pd, and A is a general formula [Formula ] [Formula] [Formula] [Formula] [Formula] A group represented by [Formula] [Formula]. In the above formula, Z is an atomic group necessary to form a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocycle, and Y is -NR ⁷ R ⁸ , -OR ⁹ or -
NHN=CH− ^R10 . R ₁ and R ² are substituted or unsubstituted alkyl groups, aralkyl groups, aryl groups, or heterocyclic groups, R ³ is an alkyl group or carboxyl group, or an ester thereof, R ⁴ , R ⁵ , R ⁸ and R ¹⁰ is a substituted or unsubstituted aryl group or heterocyclic group, and R ⁶ , R ⁷ and R ⁹ are H, substituted or unsubstituted alkyl group, aralkyl group, aryl group or heterocyclic group. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier-generating substance and a carrier-transporting substance, and the carrier-generating substance is an azo compound having a phthalocyanine skeleton represented by the above general formula (). .