JP2505156B2 - Photoconductor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photoreceptor containing a low molecular weight organic compound.

2. Description of the Related Art Generally, in electrophotography, the surface of a photosensitive layer of a photoconductor is charged and exposed to form an electrostatic latent image, which is developed with a developer to be visualized. Direct method of fixing on top to obtain a copy image, or powder image transfer method of transferring a visible image on a photoreceptor onto a transfer paper such as paper and fixing the transferred image to obtain a copy image or on a photoreceptor There is known a latent image transfer system in which an electrostatic latent image is transferred onto a transfer paper, and the electrostatic latent image on the transfer paper is developed and fixed.

Conventionally, it is known to use an inorganic photoconductive material such as selenium, cadmium sulfide, or zinc oxide as a photoconductive material to form a photosensitive layer of a photoreceptor used in this type of electrophotography. . While these photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in a dark place, having little charge dissipation in a dark place, or being able to quickly dissipate charge by light irradiation, It has various disadvantages as follows. For example, with selenium-based photoreceptors,
Manufacturing costs are high, and it is sensitive to heat and mechanical shock, so care must be taken.In addition, cadmium sulfide-based photoconductors and zinc oxide photoconductors do not provide stable sensitivity in humid environments. The dye added as a sensitizer has a drawback that stable characteristics cannot be provided over a long period of time because charge deterioration due to corona charging and photobleaching due to exposure occur.

On the other hand, various organic photoconductive polymers such as polyvinylcarbazole have been proposed, but these polymers are superior to the above-mentioned inorganic conductive materials in film-forming property and lightness. However, it is still inferior to inorganic photoconductive materials in terms of sufficient sensitivity, durability and stability due to environmental changes. The low molecular weight organic photoconductive compound is
It is preferable that the physical properties of the coating film or the electrophotographic properties can be controlled by selecting the type and composition ratio of the binder used in combination.

The photoconductor in which these high-molecular weight and low-molecular weight organic photoconductive compounds are dispersed in the binder resin has drawbacks such as a large residual potential because of many carrier traps and low sensitivity. Therefore, it has been proposed to blend an organic photoconductive compound with a charge transport material to solve the above drawbacks.

As the charge transport material, many organic compounds are mentioned, for example, 2,5-bis (p-diethylaminophenyl) -1,3,4 described in US Pat. No. 3,189,447.
-Oxadiazole, diarylalkane derivatives described in U.S. Pat.No. 3,820,989 are disclosed in JP-A-54-
The hydrazone compounds and the like described in JP-A-59143 are known.

An object of the present invention is to provide a photoconductor containing a novel enamine compound having excellent charge transporting ability.

Another object of the present invention is to provide a photoreceptor having good sensitivity and chargeability.

Means for Solving the Problems The photoconductor of the present invention is characterized by a photoconductor containing an enamine compound represented by the following general formula [I].

General formula: [Wherein R 1 is hydrogen, an alkyl group, an aralkyl group, an alkoxy group, a disubstituted amino group, R 2 is a halogen atom, R 3 and R 4 are each independently an aryl group which may have a substituent, or a heterocyclic group. Shows a condensed polycyclic group. However, n is 1 to
Indicates an integer of 3.

Specific preferred examples of the enamine compound of the present invention include:
Examples thereof include those having the following structural formulas, but the present invention is not limited thereto.

The enamine compound represented by the general formula [I] of the present invention can be easily produced by a known method.

For example, the following general formula [II] general formula: [Wherein R ₁ .. R ₂ .n has the same meaning as [I]] and a general formula [III]: [Wherein R ₃ . R ₄ can be synthesized by dehydration condensation of an amine compound represented by [I].

In the reaction, water produced using a solvent such as benzene, toluene, or xylene is generally removed azeotropically,
Potassium carbonate, P-toluenesulfonic acid, acetic acid, Dowex5
0 or using a catalyst such as Montmorillonite catalyst KIO.

A structural example of a photoconductor using the enamine compound of the present invention is schematically shown in FIGS. 1 to 5.

FIG. 1 shows a photoreceptor in which a photoconductive layer (4) in which a photoconductive material (3) and a charge transport material (2) are mixed with a binder is formed on a substrate (1). The enamine compound of the present invention is used.

FIG. 2 shows a function-separated type photoreceptor having a charge generation layer (6) and a charge transport layer (5) as a photosensitive layer. The charge transport layer (5) is formed on the surface of the charge generation layer (6). There is. The enamine compound of the present invention is blended in the charge transport layer (5).

Similar to FIG. 2, FIG. 3 shows a function-separated type photoreceptor having a charge generation layer (6) and a charge transport layer (5). On the contrary to FIG. A charge generation layer is formed.

FIG. 4 shows the surface of the photoreceptor of FIG. 1 further provided with a surface protective layer (7). The photosensitive layer (4) is separated into a charge generation layer (6) and a charge transport layer (5). It may be a function separation type.

FIG. 5 shows an intermediate layer (8) provided between the substrate (1) and the photosensitive layer (4), and the intermediate layer (8) has improved adhesion. It can be provided in order to improve the coating property, protect the substrate, and improve the charge injection property from the substrate to the photoconductive layer. As the intermediate layer, polyimide resin, polyester resin, polyvinyl butyral resin, casein or the like may be used. In the photoreceptor of this aspect, the photosensitive layer may have a function-separated type.

The photoreceptor of the present invention is prepared by dissolving or dispersing an enamine compound represented by the general formula [I] in a suitable solvent together with a binder, and if necessary, a photoconductive material and an electron-withdrawing compound, or a sensitizing dye, other The coating solution obtained by adding the pigment is coated on a conductive substrate and dried, usually 5 to 30μ
m, preferably from 6 to 20 μm.

Specifically, a function-separated type photoreceptor having the same structure as that shown in FIG. 2 which is obtained by stacking a charge generation layer and a charge transport layer on a conductive support has a photoconductive material on the conductive support. Vacuum evaporation, or an appropriate solvent or, if necessary, dispersed in a solution in which a binder resin is dissolved, is applied and dried to form a charge generating layer, on which an enamine compound and a binder are formed. It is obtained by applying a solution in which is dissolved in a suitable solvent and drying it to form a charge transport layer. At this time, the thickness of the charge generation layer is 4 μm or less, preferably 2 μm.
The thickness of the charge transport layer is 3 to 30 μm, preferably 5 to 20 μm. The proportion of the enamine compound in the charge transport layer is 0.02 to 2 parts by weight, preferably 0.03 to 1.3 parts by weight, based on 1 part by weight of the binder. Also, other charge transport materials may be combined. In the case of the polymer charge transport material which itself can be used as a binder, other binder may not be used. The photoreceptor may have a configuration in which a charge transport layer is formed on a conductive support and a charge generation layer is laminated thereon similarly to the photoreceptor of FIG.

The photosensitive layer is formed by laminating a photosensitive layer on a conductive support.
A dispersion type photoreceptor having the same structure as the photoreceptor shown in the figure is obtained by dispersing fine particles of a photoconductive material in a solution in which an enamine compound and a resin are dissolved, coating this on a conductive support and drying it. Obtained by forming layers. At this time, the thickness of the photosensitive layer is 3 to 30 μm, preferably 5 to 20 μm. If the amount of the photoconductive material used is too small, the sensitivity is poor, and if it is too large, the charging property is deteriorated or the strength of the photosensitive layer is weakened. 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, is preferable, and the ratio of the enamine compound is 0.01 to 1 part by weight of the resin.
˜2 parts by weight, preferably 0.02 to 1.2 parts by weight. It may also be used in combination with a polymer photoconductor such as polyvinyl carbazole which itself can be used as a binder. It may also be combined with other charge transport materials such as hydrazone compounds.

Examples of materials used for the photoconductive material of the photoreceptor of the present invention include bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes,
Cyanine dye, styryl dye, pyrylium dye,
Organic substances such as azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indathlon pigments, squarylium pigments, phthalocyanine pigments, selenium, selenium tellurium Inorganic substances such as selenium / arsenic, cadmium sulfide, and amorphous silicon are listed. Other than this,
Any material can be used as long as it absorbs light and generates charge carriers with extremely high efficiency.

What can be used as a binder in the present invention,
Any known electrically insulating thermoplastic resin, thermosetting resin, photocurable resin, or photoconductive resin may be used.

Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins,
Acrylic resin, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer), styrene-
Thermoplastic binders such as butadiene block copolymer, polyarylate, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin: epoxy resin, urethane resin, silicone resin, phenol resin, melamine resin, Thermosetting binders such as xylene resin, alkyd resin, and thermosetting acrylic resin; photocurable resins; photoconductive resins such as poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene and the like. These can be used alone or in combination.

These electrically insulating resins are individually measured to be 1 × 10 ¹² Ω ・
It is desirable to have a volume resistance of cm or more. More preferred are polyester resins, polycarbonates,
Acrylic resin.

The photoreceptor of the present invention, together with the binder, halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene,
Plasticizers such as dibutyl phthalate and O-ta-phenyl, chloranil, tetracyanoethylene, 2,4,7-trinitro-9-fluorenone, 5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, An electron-withdrawing sensitizer such as 3,5-dinitrobenzoic acid,
A sensitizer such as methyl violet, rhodamine B, cyanine dye, pyrylium salt and thiapyrylium salt may be used.

The photoreceptor thus formed may have an adhesive layer, an intermediate layer (8) and a surface protective layer (7) as required as shown in FIGS. 4 and 5 described above.

EFFECTS OF THE INVENTION The photoconductor of the present invention, which contains the above-mentioned enamine compound, has a remarkably excellent charge transporting ability, the initial surface potential is stable, and the dark decay rate is sufficient for the photoconductor. It is small enough to be used and has good charging ability. Further, since the photoreceptor of the present invention is excellent in charge transporting ability, it has few carriers traps and high sensitivity.

Example 1 1 part by weight of a disazo pigment represented by the following general formula [A], a polyester resin (manufactured by Byron 200 Toyobo Co., Ltd.)
1 part by weight and 50 parts by weight of tetrahydrofuran were placed in a ball mill pot and dispersed for 24 hours to obtain a photosensitive coating solution. This was applied on an aluminum substrate and dried to form a charge generation layer having a thickness of 0.5 μm.

General formula: On the charge generation layer, the above-mentioned enamine compound (3)
10 parts by weight, polycarbonate resin (Panlite K-1300
A coating liquid prepared by dissolving 10 parts by weight of Teijin Kasei Co., Ltd. in 80 parts by weight of tetrahydrofuran was applied and dried to form a charge transporting layer having a thickness of 15 μm, thereby preparing a photoreceptor.

The photoreceptor thus obtained is corona charged at −6.0 KV using a commercially available electrophotographic copying machine (Ep 360Z manufactured by Minolta Camera Co., Ltd.) to obtain an initial potential Vo (V) and an initial potential of 1/2. The exposure dose E1 / 2 (lux · sec) was measured, and the initial potential decay rate DDR ₅ (%) when left in the dark for 5 seconds was measured.

Examples 2 to 4 have the same constitution as in Example 1 except that the enamine compounds (4), (7) and (8) are used instead of the enamine compound (3) used in Example 1. A photoconductor was prepared.

Vo, E1 / 2, and DDR ₅ of the photoreceptor thus obtained were measured in the same manner as in Example 1.

Example 5 2 parts by weight of a trisazo pigment represented by the following general formula [B], a potterester resin (manufactured by Byron 200 Toyobo Co., Ltd.)
1 part by weight and 100 parts by weight of methyl ethyl ketone were placed in a ball mill pot and dispersed for 24 hours to obtain a photosensitive coating solution. This was applied onto an aluminum substrate and dried to form a charge generation layer having a thickness of 1 μm.

General formula: On the charge generation layer, the above-mentioned enamine compound (9) 10
Parts by weight, polyarylate resin (U-100 Unitika) 10
A coating solution prepared by dissolving 100 parts by weight of chlorobenzene in 100 parts by weight was applied and dried to form a charge transporting layer having a thickness of 15 μm, thereby preparing a photoreceptor.

Vo, E1 / 2, and DDR ₅ of the photoreceptor thus obtained were measured in the same manner as in Example 1.

Examples 6 to 7 Photoreceptors having the same constitution as in Example 5 but using the enamine compounds (13) and (14) instead of the enamine compound (9) used in Example 3 were prepared. did.

Vo, E1 / 2, and DDR ₅ of the photoreceptor thus obtained were measured in the same manner as in Example 1.

Example 8 Squalic acid pigment 2 represented by the following general formula [C]
Parts by weight, polyester resin (Byron 200 Toyobo Co., Ltd.)
5 parts by weight) and 100 parts by weight of methyl ethyl ketone were placed in a ball mill pot and dispersed for 24 hours to obtain a photosensitive coating solution.
This was applied onto an aluminum substrate and dried to form a charge generation layer having a thickness of 1 μm.

General formula: On the charge generation layer, 10 parts by weight of the enamine compound (15) and 10 parts by weight of a polycarbonate resin (manufactured by Panlite K-1300 Teijin Kasei Co., Ltd.) were dissolved in 80 parts by weight of tetrahydrofuran to prepare a coating solution after drying. A photoconductor was prepared by forming a charge transport layer by coating so as to have a film thickness of about 15 μm.

Vo, E1 / 2, and DDR ₅ of the photoreceptor thus obtained were measured in the same manner as in Example 1.

Example 9 50 parts by weight of copper phthalocyanine and 0.2 parts by weight of tetranitrocopper phthalocyanine were dissolved in 500 parts by weight of 98% concentrated sulfuric acid with sufficient stirring, and this was poured into 5,000 parts by weight of water to obtain photoconductivity of copper phthalocyanine and tetranitrocopper phthalocyanine. After depositing the material composition, it was filtered, washed with water, and dried at 120 ° C. under reduced pressure.

10 parts by weight of the photoconductive composition thus obtained was used as a thermosetting acrylic resin (Acridic A405 Dainippon Ink and Chemicals, Inc.)
22.5 parts by weight, melamine resin (Super Beckamine J8)
20 Dainippon Ink and Chemicals, Inc. 7.5 parts by weight 10 parts by weight of the above-mentioned enamine compound (16) are placed in a ball mill pot together with 100 parts by weight of a mixed solvent prepared by mixing equal amounts of methyl ethyl ketone and xylene, and dispersed for 48 hours for photoconductivity. A photosensitive coating liquid was prepared, and the coating liquid was applied onto an aluminum substrate and dried to form a photosensitive layer having a thickness of about 15 μm to prepare a photoconductor.

Vo, E1 / 2 and DDR ₅ of the thus obtained photoreceptor were measured in the same manner as in Example 1 except that corona charging was performed at +6 KV.

Examples 10 to 12 The same method as in Example 9 was used, but the enamine compounds (17), (19) and (20) were used instead of the enamine compound (16) used in Example 9, respectively. Was prepared.

Vo, E1 / 2, and DDR ₅ of the photoreceptor thus obtained were measured in the same manner as in Example 9.

The measurement results of Vo, E1 / 2, DDR ₅ of photoreceptors of Examples 1-12 shown in Table 1.

As is clear from Table 1, the photoconductor containing the enamine compound of the present invention always has an initial surface potential of 600 V or more, regardless of whether it is a function-separated type or a dispersion type, and the dark decay rate is sufficient to be used as a photoconductor. Very small and excellent in charging ability. Further, it is clear that the half-exposure amount is about 2 to 4 lux · sec and the sensitivity is stable, and the electrophotographic characteristics are excellent.

[Brief description of drawings]

1 to 5 are schematic views of a photoreceptor according to the present invention, and FIGS. 1, 4, and 5 are dispersion type photoreceptors in which a photosensitive layer is laminated on a conductive support. 2 and 3 show the structure of a function-separated type photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support. DESCRIPTION OF SYMBOLS 1 ... Conductive support, 2 ... Charge transport material 3 ... Photoconductive material, 4 ... Photosensitive layer 5 ... Charge transport layer, 6 ... Photoconductive layer 7 ... Surface protective layer, 8 ... Intermediate layer

Claims (1)

(57) [Claims] 1. A photoconductor containing an enamine compound represented by the following general formula [I]. General formula: [Wherein R 1 is hydrogen, an alkyl group, an aralkyl group, an alkoxy group, a disubstituted amino group, R 2 is a halogen atom, R 3 and R 4 are each independently an aryl group which may have a substituent, or a heterocyclic group. Shows a condensed polycyclic group. However, n is 1 to
Indicates an integer of 3. ]