JPH11305461A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having good well- balanced electrification ability, sensitivity, dark attenuation, residual potential, environmental characteristics and repetitive characteristics. SOLUTION: Relating to an electrophotographic photoreceptor obtd. by forming a photosensitive layer on an electrically conductive substrate, a dialkoxy- (or haloalkoxy-)silicon phthalocyanine compd. is used as an electric charge generating material and a compd. having a butadiene skeleton is used as an electric charge transferring material. The objective electrophotographic photoreceptor excellent particularly in sensitivity characteristics and electric charge retentivity is obtd. This photoreceptor can be effectively used in a printer, a facsimile or a copying machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor having high sensitivity and excellent characteristics from a visible region to a near-infrared wavelength region. is there. Hereinafter, the electrophotographic photosensitive member is abbreviated as a photosensitive member.

[0002]

2. Description of the Related Art In recent years, laser light has been used as a light source to increase the speed,
2. Description of the Related Art Laser printers, which have advantages of high image quality and non-impact, have come into widespread use, and photoconductors capable of meeting the demands have been actively developed. In particular, a method using a semiconductor laser as a light source is mainly used, and the wavelength of the light source is 780 nm.
There is a strong demand for a photoreceptor having high sensitivity to long wavelength light before and after.

Under the circumstances described above, phthalocyanine compounds are (1) relatively easily synthesized;
(2) having an absorption peak in a long wavelength region of 600 nm or more; (3) the spectral sensitivity varies depending on the central metal and crystal form;
Several compounds exhibiting high sensitivity in the wavelength range of semiconductor lasers have been published, and research and development are being vigorously conducted.

In the case of phthalocyanine compounds such as copper phthalocyanine, α, γ, ε, π,
Crystal forms such as χ, τ, ρ, and δ are known, and these crystal forms can be mutually transferred by mechanical strain, sulfuric acid treatment, organic solvent treatment, heat treatment, etc. (Organic Electronics Materials Series) 6 "Phthalocyanine"). The absorption spectrum and photoconductivity of the phthalocyanine compound vary depending not only on the type of the central metal but also on the crystal form as described above. Are different.

Japanese Patent Application Laid-Open No. 50-38543 discloses that, with respect to the crystal form and electrophotographic properties of copper phthalocyanine, the ε form shows the highest sensitivity in comparison with the α, β, γ and ε forms. ing. On the other hand, as for hydroxymetal phthalocyanine, a photoreceptor using dihydroxygermanium phthalocyanine, dihydroxytin phthalocyanine or dihydroxysilicon phthalocyanine is described in U.S. Pat. No. 4,557,989. JP-A-3-73661 describes an electrophotographic photosensitive member using halogenated silicon phthalocyanine or dihydroxysilicon phthalocyanine.
JP-A-214415 reports an electrophotographic photoreceptor using hydroxymetal phthalocyanine (Al, Ga, In, Si, Ge, Sn), and presents one crystal form for dihydroxysilicon phthalocyanine. .

[0006]

However, the conventionally proposed photoreceptor is not always sufficient in electrophotographic characteristics. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photoreceptor having good chargeability, sensitivity, dark decay, residual potential, environmental characteristics, repetition characteristics, and the like, and having a good balance. It is in.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be easily achieved if specific compounds are used in combination as a charge generating material and a charge transporting material. The knowledge was obtained and the present invention was completed.

That is, the gist of the present invention is to provide an electrophotographic photosensitive member having a photosensitive layer formed on a conductive support, wherein a dialkoxy (or halogenated alkoxy) silicon phthalocyanine compound is used as a charge generating material; An electrophotographic photoreceptor comprising a compound having a butadiene skeleton as a charge transport material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
First, the charge generating material (dialkoxy (or halogenated alkoxy) silicon phthalocyanine compound) and the charge transporting material (compound having a butadiene skeleton) in the photoreceptor of the present invention will be described.

The basic structure of the silicon phthalocyanine compound used in the present invention is represented by the following general formula (I).

[0011]

Embedded image

In the general formula (I), OR ¹ and OR ² each represent an alkoxy group or a halogenated alkoxy group having 1 to 8 (preferably 1 to 6) carbon atoms, which may be the same or different. . Specific examples of the alkoxy group having 1 to 8 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, ter-butoxy, pentoxy, hexoxy, cyclohexoxy, Examples include a heptoxy group and an octoxy group, and specific examples of the halogenated alkoxy group having 1 to 8 carbon atoms include an alkoxy group in which the alkyl group of the above alkoxy group is substituted with a halogen atom. Among them, an alkoxy group having 1 to 6 carbon atoms is preferable. Further, the silicon phthalocyanine compound may contain an alkyl, alkoxy, or halogen atom-substituted substrate.

The above-mentioned silicon phthalocyanine compound is
For example, it can be manufactured by the following method. That is, first, after heating 1,3-diiminoisoindoline or phthalodinitrile and silicon tetrachloride in a solvent, the reaction product is filtered, washed, and purified to obtain a dichlorosilicon phthalocyanine compound. Next, a dialkoxysilicon phthalocyanine compound is produced by treating the dichlorosilicon phthalocyanine compound with sodium alkoxide in an alcohol solvent. Then, the product is isolated from the processing solvent, washed and dried.

On the other hand, the compound having a butadiene skeleton used in the present invention includes, for example, the following chemical formulas (1) to
The compound represented by (21) is mentioned.

The photoreceptor of the present invention comprises a photosensitive layer formed on a conductive support, and a charge generation material (dihydroxysilicon phthalocyanine compound) and a charge transport material (compound having a butadiene skeleton) in the photosensitive layer. And The photosensitive layer is usually configured as a laminated type, but may be a single layer (single layer) type.

The laminated photosensitive layer is formed by laminating a charge generation layer and a charge transport layer in any order. The charge generation layer is formed by a vapor deposition method or a coating method using a dispersion of a charge generation material and a binder, and the charge transport layer is formed by a casting method from an organic solvent solution or the above-described coating method. On the other hand, the single-layer photosensitive layer is formed by a coating method using a dispersion of a charge generation material, a charge transport material, and a binder. And the photoreceptor of the present invention has an adhesive layer,
In addition to an intermediate layer such as a blocking layer, a protective layer for improving electric characteristics and mechanical characteristics may be provided.

Examples of the conductive support include metal drums and sheets of aluminum, copper, nickel and the like, and laminates and vapor-deposits of these metal foils. Furthermore, conductive materials (metal powder, carbon black, copper iodide, polymer electrolyte, etc.) are applied together with a suitable binder, and the conductive material is contained in addition to conductive films, plastic drums, paper, etc. And a plastic film having on its surface a layer of a conductive metal oxide (such as tin oxide or indium oxide).

The blocking layer is formed on the surface of the conductive support, and is effective in preventing unnecessary charge injection from the conductive support. Further, the blocking layer has an effect of increasing the charge of the photosensitive layer and also an effect of increasing the adhesion between the photosensitive layer and the conductive support.

Materials constituting the blocking layer include inorganic materials such as aluminum anodic oxide film, aluminum oxide, aluminum hydroxide, titanium oxide, and surface-treated titanium oxide, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, and gelatin. And organic layers of starch, polyurethanes, polyimides, polyamides, etc., and other organic zirconium compounds, titanium chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, and the like. The thickness of the blocking layer is usually 0.1 to 20 mm,
Preferably it is in the range of 0.1 to 10 mm.

In the case of the laminated type photosensitive layer, the charge generation layer formed by the coating method includes a charge generation material and a binder,
If necessary, the composition contains an organic photoconductive compound, a coloring matter, and an electron-withdrawing compound.

Examples of the organic photoconductive compound include phthalocyanine compounds such as dialkoxysilicon phthalocyanine, titanyl phthalocyanine, gallium phthalocyanine, indium phthalocyanine, and metal-free phthalocyanine, azo compounds, anthraquinone compounds, perylene compounds, and polycyclic quinones. And methine squaric acid-based compounds.

Examples of the binder (binder resin) include vinyl compounds such as styrene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylate, methacrylate, acrylamide, acrylonitrile, vinyl alcohol, ethyl vinyl ether and vinyl pyridine. Polymers and copolymers, phenoxy resins, polysulfone resins, polyvinyl acetal resins, polyvinyl butyral resins, polycarbonate resins, polyester resins,
Examples include polyamide resin, polyurethane resin, cellulose ester resin, cellulose ether resin, epoxy resin, silicon resin, alkyd resin, polyarylate resin, and the like.

The coating solution for the charge generation layer is prepared by dispersing (partially dissolving) the charge generation material in a binder solution. Examples of the organic solvent include ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether; ketones such as acetone, methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; halogenated aromatics such as monochlorobenzene and dichlorobenzene. Aliphatic hydrocarbons, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, halogenated aliphatic hydrocarbons such as trichloroethane, methanol, ethanol, alcohols such as isopropanol, methyl acetate,
Esters such as ethyl acetate; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; and sulfoxides such as dimethyl sulfoxide.

The ratio of the binder used is as follows.
It is usually in the range of 1 to 1000 parts by weight, preferably 10 to 400 parts by weight, based on 00 parts by weight. Examples of the dispersion method include a method using a ball mill, a sand grind mill, a planetary mill, a roll mill, a paint shaker, and the like.

Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, a curtain coating method, and a ring coating method.

Drying after coating is performed, for example, at 25 to 250 ° C.
At a temperature of 5 minutes to 3 hours in a stationary or blown state. Further, the thickness of the formed charge generation layer is
Usually, the range of 0.1 to 5 mm is appropriate.

The charge transport layer of the layered photosensitive layer contains additives such as an antioxidant, if necessary, in addition to the charge transport material and the binder. As the binder, the same insulating resin as described above can be used. The binder is used in an amount of usually 20 to 3000 parts by weight, preferably 50 to 1000 parts by weight, based on 100 parts by weight of the charge transporting material. The charge transport layer is formed by applying and drying a coating solution prepared using the same organic solvent as described above, and the thickness of the charge transport layer is usually in the range of 5 to 50 mm.

The photosensitive layer of the single-layer type photosensitive layer contains a charge generating material, a charge transporting material, and a binder. A charge generating substance other than the dihydroxysilicon phthalocyanine compound may be used in combination. As the binder, the same insulating resin as described above can be used. Further, if necessary, various additives such as an antioxidant and a sensitizer may be contained.

The binder is used in an amount of usually 2 to 300 parts by weight based on 10 parts by weight of the charge generating material and the charge transporting material. A suitable range is from 100 to 100 parts by weight. The single-layer type photosensitive layer is formed by applying and drying a coating solution prepared using the same organic solvent as described above.

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Synthesis Example 1 (Synthesis of dichlorosilicon phthalocyanine) 43.5 g of 1,3-diiminoisoindoline and 73.5 g of silicon tetrachloride were added to 500 ml of quinoline, and heated at 210 to 220 ° C. for 1 hour under a nitrogen atmosphere. Reacted. The product was hot-filtered at 180 ° C., and washed with quinoline and acetone in this order. Then, the mixture was heated under reflux in 300 ml of acetone, and the crystals were separated by filtration and dried to obtain 38.7 g of dichlorosilicon phthalocyanine.

The structural analysis was performed by mass spectrum (negative measurement), IR (KBr method), and elemental analysis. FIG. 1 shows a mass spectrum of dichlorosilicon phthalocyanine, and FIG. 2 shows an IR spectrum. M / z in mass spectrum:
At 610, a peak of dichlorosilicon phthalocyanine was confirmed. m / z: 575 is a fragment peak from which one chlorine atom has deviated.

In the IR spectrum, 1533, 1079, 1060 cm
^-1 showed an absorption characteristic of dichlorosilicon phthalocyanine (E. Cilibertoetal., J. Am. Chem. Soc., 106, 7748 (19
84)). The results of the elemental analysis are shown below, which are almost the same as the calculated values. As a result of structural analysis, the synthesized product was identified as dichlorosilicon phthalocyanine.

[0040]

Table 1 C (%) H (%) N (%) Si (%) Cl (%) Found 62.65 2.58 18.12 4.48 12.21 Calculated 62.85 2.62 18 .33 4.58 11.62

FIG. 3 shows an X-ray diffraction spectrum of the above dichlorosilicon phthalocyanine. 2θ = 10.7, 12.3, 1
It has peaks at 5.5, 17.6, 19.9, 24.6, 26.8, and 27.6 °, respectively.

Synthesis Example 2 (Synthesis of dimethoxysilicon phthalocyanine) Dichlorosilicon phthalocyanine 1 synthesized in Synthesis Example 1
0 g of sodium methoxide 1.86 g, methanol 1
The mixture was added to a mixture of 00 ml and 100 ml of pyridine and reacted under reflux for 3 hours. The product is filtered hot, methanol,
Washing was performed in the order of water and acetone. Then, after repeating washing several times in 100 ml of water, the neutrality was confirmed, and the crystals were separated by filtration.
After drying, 9.7 g of dimethoxysilicon phthalocyanine was obtained.

The structural analysis was performed in the same manner as in Synthesis Example 1. FIG. 4 shows a mass spectrum of dimethoxysilicon phthalocyanine. In the mass spectrum, a peak of dimethoxysilicon phthalocyanine was confirmed at m / z: 602. m / z:
571 is a fragment peak from which one methoxy group has been removed. The results of the elemental analysis are shown below, which are almost the same as the calculated values. As a result of structural analysis, the synthesized product was identified as dimethoxysilicon phthalocyanine.

[0044]

Table 2 C (%) H (%) N (%) Si (%) Found 68.02 3.72 18.71 4.70 Calculated 67.78 3.65 18.60 4.65

FIG. 5 shows an X-ray diffraction spectrum of the above dimethoxysilicon phthalocyanine. 2θ = 8.1, 12.2,
It has peaks at 13.0, 17.0, 18.7, 23.3, 26.0, 27.8, and 30.4 °, respectively.

Synthesis Example 3 (Synthesis of diethoxy silicon phthalocyanine) Dichlorosilicon phthalocyanine 3 synthesized in Synthesis Example 1
g, sodium methoxide 0.68 g, methanol 50
The mixture was added to a mixture of 50 ml of pyridine and 50 ml of pyridine, and reacted under reflux for 3 hours. The product was filtered hot and washed in the order of ethanol, water and acetone. Next, washing was repeated several times in 50 ml of water, and after confirming neutrality, the crystals were separated by filtration and dried to obtain 2.7 g of diethoxysilicon phthalocyanine.

The structural analysis was carried out by mass spectrum (negative measurement) and IR (KBr method). FIG. 6 shows a mass spectrum of diethoxy silicon phthalocyanine. In the mass spectrum, a peak of diethoxy silicon phthalocyanine was confirmed at m / z: 630. m / z: 586 is a fragment peak from which one ethoxy group was removed. FIG. 7 shows an X-ray diffraction spectrum of the above-mentioned diethoxy silicon phthalocyanine. 2θ = 8.4, 10.9, 11.7, 14.6, 16.7, 17.2,
It has peaks at 24.6 and 26.8 °, respectively.

Synthesis Example 4 (Synthesis of diisopropoxy silicon phthalocyanine) Dichlorosilicon phthalocyanine 3 synthesized in Synthesis Example 1
g of sodium isopropoxide was added to a mixture of 0.82 g of sodium isopropoxide, 50 ml of methanol and 50 ml of pyridine, and the mixture was reacted under reflux for 3 hours. The product was filtered hot and washed in the order of isopropanol, water and acetone. Next, washing was repeated several times in 50 ml of water, and after confirming neutrality, the crystals were separated by filtration and dried to obtain 2.7 g of diisopropoxysilicon phthalocyanine.

The structural analysis was carried out by mass spectrum (negative measurement) and IR (KBr method). FIG. 8 shows a mass spectrum of diisopropoxysilicon phthalocyanine.
In the mass spectrum, a peak of diisopropoxysilicon phthalocyanine was confirmed at m / z: 658. m / z: 600
Is a fragment peak from which one isopropoxy group has been removed. FIG. 9 shows an X-ray diffraction spectrum of the above diisopropoxy silicon phthalocyanine. 2θ = 9.2, 13.0,
It has peaks at 15.3, 16.8, and 26.3 °, respectively.

Example 1 0.4 g of dimethoxysilicon phthalocyanine produced in Synthesis Example 2 was pulverized together with 30 g of 4-methoxy-4-methylpentanone-2 by a sand grind mill for 6 hours, and subjected to a fine particle dispersion treatment. Next, polyvinyl butyral (Denka Butyral # 6000C, manufactured by Denki Kagaku Kogyo KK)
0.1 g and phenoxy resin (Union Carbide Co., Ltd.)
(UCAR), 0.1 g of 4-methoxy-4-methylpentanone-2 solution (10%) to prepare a dispersion. This dispersion was applied onto a polyester film on which aluminum was deposited by a bar coater and dried to form a charge generation layer (film thickness after drying: 0.4 μm). Next, 7.0 g of a butadiene compound (a) shown below was placed on the charge generation layer.
A solution in which 10 g of a polycarbonate resin was dissolved in 62 g of THF was applied by an applicator and dried to form a charge transport layer (film thickness after drying: 20 μm).

Examples 2 to 4 and Comparative Example 1 In the same manner as in Example 1 except that the charge generation materials listed in Table 3 below and the following butadiene compounds (a), (b) or β-TiOPc were used. A photoreceptor was made.

[0052]

Embedded image

[0053]

[Table 3]

Next, using an electrostatic copying paper tester (“Model EPA-8100” manufactured by Kawaguchi Electric Works), the initial electrical characteristics (charge potential, dark decay, half-reduction exposure sensitivity,
(Residual potential). As an evaluation method, the photoreceptor is negatively charged by corona discharge at an applied voltage set so that the corona current becomes 22 mA in a dark place (the surface potential at this time is referred to as a charged potential). Monochromatic light (1.0mW
/ cm ² ) was continuously exposed for 10 seconds and the decay of the surface potential was measured (the surface potential after 10 seconds of exposure was defined as the residual potential). The dark decay was defined as a potential which decreased one second after charging, and the half-exposure sensitivity was determined by the exposure (E1 / 2) required for the surface potential to decrease from -450 V to -225 V. Table 4 shows the results.

[0055]

[Table 4]

[0056]

According to the present invention described above, an electrophotographic photoreceptor having particularly excellent sensitivity characteristics and charge retention is provided. The electrophotographic photoreceptor of the present invention is effectively used for printers, facsimile machines, and copiers. It can be suitably used.

[Brief description of the drawings]

FIG. 1 is a mass spectrum diagram of a dichlorosilicon phthalocyanine compound obtained in Synthesis Example 1.

FIG. 2 is an IR spectrum of the dichlorosilicon phthalocyanine compound obtained in Synthesis Example 1.

FIG. 3 is an X-ray diffraction diagram of the dichlorosilicon phthalocyanine compound obtained in Synthesis Example 1.

FIG. 4 is a mass spectrum diagram of the dimethoxysilicon phthalocyanine compound obtained in Synthesis Example 2.

FIG. 5 is an X-ray diffraction diagram of the dimethoxysilicon phthalocyanine compound obtained in Synthesis Example 2.

FIG. 6 is a mass spectrum diagram of the diethoxysilicon phthalocyanine compound obtained in Synthesis Example 3.

FIG. 7 is an X-ray diffraction diagram of the diethoxysilicon phthalocyanine compound obtained in Synthesis Example 3.

FIG. 8 is a mass spectrum diagram of the diisopropoxysilicon phthalocyanine compound obtained in Synthesis Example 4.

FIG. 9 is an X-ray diffraction diagram of the diisopropoxysilicon phthalocyanine compound obtained in Synthesis Example 4.

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a photosensitive layer formed on a conductive support, wherein a dialkoxy (or halogenated alkoxy) silicon phthalocyanine compound is used as a charge generating material, and a butadiene skeleton is used as a charge transporting material. An electrophotographic photosensitive member comprising a compound having the following formula: