JP2914462B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member containing a novel p-phenylenediamine derivative.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, zinc oxide, and silicon have been known for electrophotographic photoreceptors, and have been extensively studied and put to practical use. . In recent years, organic photoconductive materials have been actively studied for these inorganic materials, and some of them have been put to practical use as photoconductors for electrophotography.

Generally speaking, inorganic materials such as selenium photoreceptors have thermal stability, deterioration of characteristics due to crystallization, difficulty in production, and cadmium sulfide have moisture resistance and durability. Organic materials have better film-forming properties, better flexibility, and lighter Because of its advantages such as good transparency and easy design of a photoreceptor for a wide range of wavelengths by an appropriate sensitization method, its practical use is gradually receiving attention.

Incidentally, the photoreceptor used in the electrophotographic technology is generally required to have the following basic properties. That is, (1) high chargeability against corona discharge in a dark place, (2) little leakage (dark decay) of the obtained charge in a dark place, (3) charge charge by light irradiation (4) The residual charge after light irradiation is small.

[0005]

However, a number of studies have been made on photoconductive polymers such as polyvinyl carbazole as organic photoconductive substances to date, but these have not necessarily been of film-forming properties and of good properties. Flexibility and adhesiveness are not sufficient, and it is difficult to say that the photoconductor has the above-described basic properties.

On the other hand, as for the organic low-molecular-weight photoconductive compound, a photoreceptor having excellent mechanical strength such as film property, adhesion and flexibility can be obtained by selecting a binder or the like used for photoreceptor formation. Although it can be obtained, it is difficult to find a compound that is suitable for retaining high-sensitivity properties.

In order to improve such a point, an organic photoreceptor having higher sensitivity characteristics has been developed in which a carrier generating function and a carrier transporting function are shared by different substances. The feature of such a photoreceptor, which is called a function-separated type, is that a material suitable for each function can be selected from a wide range. Has been advanced.

As described above, various improvements have been made in the preparation of an electrophotographic photoreceptor. However, the electrophotographic photoreceptor satisfies the basic characteristics required for the photoreceptor and the requirements for high durability. What to do has not yet been obtained.

An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and high durability. In particular, it is an object of the present invention to provide a photoreceptor which has a high charging characteristic, has almost no decrease in sensitivity even when used repeatedly, and has a stable charging potential.

[0010]

The present inventors have studied a photoconductive substance having high sensitivity and high durability.
The present inventors have found that the novel p-phenylenediamine derivative represented by the following formulas (1) to (3) is effective, and have reached the present invention.

In Chemical Formula 1, R ₁ and R _{2 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group or an aryl group which may have a substituent, and R ₃ and R ₄ represent a halogen atom and a substituent Represents an alkyl group, an aralkyl group, or an aryl group which may have 1 and l and m each represent an integer of 0 to 4.
In Chemical Formula 2, R ₅ , R ₆ , and R ₇ represent a halogen atom, an alkyl group which may have a substituent, an aralkyl group, or an aryl group, and n, p, and q each represent an integer of 0 to 4. . Chemical 3
Wherein R ₈ , R ₉ and R ₁₀ represent a halogen atom, an alkyl group which may have a substituent, an aralkyl group or an aryl group, X represents an oxygen atom or a sulfur atom, and r, s and t represent Each represents an integer of 0 to 4.

Here, specific examples of R _{1 to} R ₂ include a hydrogen atom, a halogen atom such as fluor, chloro, and bromo; an alkyl group such as a methyl group, an ethyl group and a propyl group; a benzyl group; a methylbenzyl group; Aralkyl groups such as chlorobenzyl group, β-phenylethyl group, α-naphthylmethyl group,
Aryl groups such as a phenyl group, a methoxyphenyl group, a tolyl group, a chlorophenyl group, and a naphthyl group can be exemplified. Specific examples of R _{3 to} R ₁₀ include halogen atoms such as fluor, chloro and bromo, and methyl groups. , Alkyl groups such as ethyl group and propyl group, benzyl group, methylbenzyl group, chlorobenzyl group, aralkyl groups such as β-phenylethyl group, α-naphthylmethyl group, phenyl group, methoxyphenyl group, tolyl group, chlorophenyl group And an aryl group such as a naphthyl group. Also, l,
When the value of each of m, n, p, q, r, s, and t is 2 or more, the substituents represented by R _{3 to} R ₁₀ may be the same or different .

The compounds represented by the formulas (1) to (3) can be produced by the methods of the following synthesis examples. Synthesis Example (Synthesis of Exemplified Compound 5)

[0014]

Embedded image

Indole of Chemical Formula 4 (14.0 g), p-dibromobenzene (11.8 g), potassium carbonate (16.
6 g) and cuprous bromide (0.3 g) were stirred and suspended in nitrobenzene (50 ml) and heated at 210 ° C. for 12 hours. After the product was subjected to steam distillation to remove nitrobenzene, the residue was washed with 500 ml of ethyl acetate, insolubles were extracted with 200 ml of benzene, and purified by silica gel chromatography to obtain 4.86 g of the crystal of Exemplified Compound 5. Obtained.

207.0-208.5 ° C. NMR (δ, ppm, CDCl ₃ ) 7.71 (d, 2H), 7.63 (s, 4H), 7.6
2 (d, 2H), 7.37 (d, 2H), 7.1 to 7.
3 (m, 4H), 6.73 (d, 2H)

The compounds represented by Chemical Formulas 2 and 3 can be synthesized in the same manner.

Next, p-phenylenediamine derivatives according to the present invention will be exemplified, but the present invention is not limited thereto.

The following compounds are exemplified as the compound represented by Chemical formula 1.

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

The following compounds are exemplified as the compounds represented by Chemical formula 2.

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image

[0041]

Embedded image

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

The following compounds are exemplified as the compounds represented by the chemical formula (3).

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

The electrophotographic photoreceptor according to the present invention is obtained by containing one or more kinds of the above-mentioned p-phenylenediamine derivatives and has excellent performance.

Various methods are known for using these p-phenylenediamine derivatives as electrophotographic photosensitive members. For example, a p-phenylenediamine derivative and a sensitizing dye may be dissolved or dispersed in a binder resin by adding a chemical sensitizer or an electron-withdrawing compound as necessary, and provided on a conductive support. In the form of a photoreceptor or a laminated structure composed of a carrier generating layer and a carrier transporting layer, a carrier generating layer having a high carrier generating efficiency, such as a dye or a pigment, is mainly provided on a conductive support. A photoreceptor comprising a p-phenylenediamine derivative to which a chemical sensitizer or an electron-withdrawing compound is added, if necessary, and dissolved or dispersed in a binder resin as a carrier transport layer; There is a photoreceptor obtained by laminating a carrier generation layer and a carrier transport layer on a conductive support in reverse, and the present invention can be applied to any case.

As a support for preparing a photoreceptor using the compound of the present invention, a metal drum, a metal plate, a paper which has been subjected to conductive processing, a plastic film or a belt-like support is used. As the film-forming binder resin used for forming a photosensitive layer on such a support, various resins can be mentioned depending on the application field. For example, for photoreceptors for copying, polystyrene resin, polyvinyl acetate
Resin, polysulfone resin, polycarbonate resin, vinyl acetate / crotonic acid copolymer resin, polyphenylene oxide resin, polyester resin, alkyd resin, polyarylate resin, acrylic resin, methacrylic resin, phenoxy resin and the like. Among them, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, polyarylate resin, phenol resin and the like are excellent in the potential characteristics as a photoconductor.

These resins can be used alone or in combination of two or more kinds as a copolymer. The amount added to the photoconductive compound of these binder resins is
The ratio is 0.2 to 10 times by weight, preferably 0.1 to 10 times.
When the amount is less than 5 to 5 times, the photoconductive compound precipitates in the photosensitive layer or on the surface, and the adhesion to the support is deteriorated. When the amount is more, the sensitivity is lowered.

Next, some of the film-forming binder resins to be used are rigid and have low mechanical strength such as tension, bending, compression, etc. In the case where a substance giving plasticity is added to improve these properties. Is also required. These materials include phthalic acid esters (eg, DOP, DBP,
Phosphoric acid ester (eg, TCP, TOP)
And the like, sebacic esters, adipic esters, nitrile rubbers, chlorinated hydrocarbons and the like. In the case of adding such a substance that imparts plasticity, the addition of more than necessary deteriorates the potential characteristics. Therefore, the ratio is preferably 20% or less by weight with respect to the binder resin.

Next, sensitizing dyes added to the photosensitive layer include triphenylmethane dyes represented by methyl violet, crystal violet, ethyl violet, night blue and Victoria blue, erythrosine, rhodamine B and rhodamine 3B. , Aziridine dyes such as acridine orange 2G, acridine orange R, and flaveosin, thiazine dyes such as methylene blue and methylene green, capri blue, and meldra blue. Oxazine dyes, other cyanine dyes, styryl dyes, pyrylium salts, thiapyrylium salts, and squarium salt dyes.

Examples of photoconductive pigments that generate carriers with extremely high efficiency by light absorption in the photosensitive layer include metal-free phthalocyanines, phthalocyanine-based pigments such as phthalocyanine containing various metals or metalized compounds, peryleneimide, and the like. There are perylene pigments such as perylene anhydride, other quinacridone pigments, anthraquinone pigments, and azo pigments.

Among these pigments, those using bisazo pigments, trisazo pigments, and phthalocyanine pigments, which have a high carrier generation efficiency, provide high sensitivity and an excellent electrophotosensitive material. Further, the dye added to the above-mentioned photosensitive layer can be used alone as a carrier-generating substance. However, by coexisting with a pigment, a carrier may be generated with higher efficiency. Further, as the inorganic photoconductive substance, selenium, selentellurium alloy, cadmium sulfide,
Examples include zinc sulfide and amorphous silicon. In addition to the above-mentioned sensitizers (so-called spectral sensitizers), sensitizers (so-called chemical sensitizers) for the purpose of further improving the sensitivity can be added.

Examples of the chemical sensitizer include p-chlorophenol, m-chlorophenol, p-nitrophenol, 4-chloro-m-cresol, p-chlorobenzoylacetanilide, N, N'-diethylbarbituric acid , 3- (β-oxyethyl) -2-phenylimino-thiazolidone, malonic acid dianilide, 3,5,3 ′,
5'-tetrachloromalonic acid dianilide, α-naphtho-
And p-nitrobenzoic acid.

Further, a certain kind of electron-withdrawing compound can be added as a sensitizer for forming a charge transfer complex with the p-phenylenediamine derivative of the present invention and further increasing the sensitizing effect. Examples of the electron-withdrawing substance include 1-chloroanthraquinone, 1-nitroanthraquinone, 2,3
-Dichloro-naphthoquinone, 3,3-dinitrobenzophenone, 4-nitrobenzalmalonenitrile, phthalic anhydride, 3- (α-cyano-p-nitrobenzal) phthalide, 2,4,7-trinitrofluorenone, 1-methyl -4-nitrofluorenone, 2,7-dinitro-3,6
-Dimethylfluorenone and the like. In addition, an antioxidant, an anti-curl agent and the like can be added as necessary to the photoreceptor.

The p-phenylenediamine derivative of the present invention is dissolved or dispersed in an appropriate solvent together with the above-mentioned various additives depending on the form of the photoreceptor, and the coating solution is coated on the conductive support described above. To form a photoreceptor.

Examples of the coating solvent include halogenated hydrocarbons such as chloroform, dichloroethane, trichloroethane and trichloroethylene, aromatic hydrocarbons such as benzene, toluene and xylene, dioxane, tetrahydrofuran, methyl cellosolve, dimethyl cellosolve, methyl cellosolve acetate and the like. Can be used alone or as a mixture of two or more solvents or, if necessary, a solvent such as alcohols, acetonitrile, N, N-dimethylformamide, methyl ethyl ketone or the like.

[0070]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1

[0071]

Embedded image

1 part by weight of the bisazo pigment of Chemical formula 41 and 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed together with glass beads for 2 hours by a paint conditioner. The pigment dispersion thus obtained was coated on an aluminum-evaporated polyester film using an applicator and dried to form a film of a carrier-generating substance having a thickness of about 0.2 μm.

Next, the p-phenylenediamine derivative represented by Exemplified Compound 5 was mixed with a polyarylate resin (U-polymer manufactured by Unitika) at a weight ratio of 1: 1 to prepare a 10% solution using dichloroethane as a solvent. This solution was applied on the carrier-generating substance film by an applicator to form a carrier transport layer having a dry film thickness of 20 μm.

The laminated electrophotographic photosensitive member thus produced was evaluated for electrophotographic characteristics using an electrostatic recording tester (SP-428, manufactured by Kawaguchi Electric). Measurement conditions: applied voltage -6
KV, static No.3. As a result, the light half-life exposure amount with respect to white light during charging was 2.0 lux · sec, which was a very high sensitivity value.

Further, repeated use was evaluated using the same apparatus. 10 ³ iterations with the place of obtaining the change in the charge potential at times, to first initial potential 920V, 10 ³ th initial potential of a 910V, see that a reduction in potential due to repeated is less stable And excellent properties.

Examples 2 to 5 A laminated photoreceptor was prepared in the same manner as in Example 1 except that the p-phenylenediamine derivative shown in Table 1 was used instead of the p-phenylenediamine derivative used in Example 1. ,
Under the same measurement conditions as in Example 1, the light half-life exposure amount E1 / 2 (lux · second) and the initial potential Vo (volt) were measured, and the values are shown in Table 1. Further, charging-discharging (discharging light: irradiation with white light at 400 lux for 1 second) is performed as one cycle, and
0 after a similar repeated ^three times the initial potential Vo (volts)
Table 1 shows the half-life exposure amount E1 / 2.

[0077]

[Table 1]

Examples 6 to 9 Titanium oxyphthalocyanine was used as a charge generating substance. That is, 1 part by weight of titanium oxyphthalocyanine and 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed together with glass beads for 2 hours using a paint conditioner. The dispersion thus obtained was applied on the same support as in Example 1 using an applicator to form a carrier generating layer. The thickness of this thin film was about 0.2 μ.

[0079]

Embedded image

[0080]

Embedded image

Next, a carrier transport layer was formed in the same manner as in Example 1 using each of the exemplified compounds shown in Table 2 and the comparative compounds represented by Chemical Formulas 42 and 43, to thereby produce a laminated photoreceptor. This photoreceptor was evaluated under the same measurement conditions as in Example 1. The results are shown in Table 2.

[0082]

[Table 2]

[0083]

As is apparent from the above, according to the present invention, an electrophotographic photosensitive member having high sensitivity and high durability can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/06 315 G03G 5/06 318 C07D 209/86 C07D 209/88

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a layer containing at least one of the p-phenylenediamine derivatives represented by the following formulas (1) to (3). Embedded image (In the formula ₁ , R ₁ and R ₂ represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, or an aryl group which may have a substituent, and R ₃ and R _{4 each} have a halogen atom and a substituent. An alkyl group, an aralkyl group, or an aryl group, and l and m each represent an integer of 0 to 4.) (Wherein, R ₅ , R ₆ , and R ₇ represent a halogen atom, an alkyl group which may have a substituent, an aralkyl group, or an aryl group, and n, p, and q each represent an integer of 0 to 4. ). (Wherein R ₈ , R ₉ and R ₁₀ represent a halogen atom, an alkyl group which may have a substituent, an aralkyl group or an aryl group, X represents an oxygen atom or a sulfur atom, and r and s ,
t represents an integer of 0 to 4, respectively. )