JPH04338759A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a sensitive body using an electric charge transferring material having electron transferring ability and to ensure excellent electrophotographic performance by incorporating a specified compd. CONSTITUTION:This sensitive body contains a compd. represented by formula I or II as an electric charge transferring material in the photosensitive layer. In the formula I, each of X and Y is =O, =Se, =Te, =C=O, =C=C(CN)2, =C=N(CN), =C=C(CN)(COOR) or =C=C(H)(CN) and Z is =O, =S, =Se, =Te, =N(R), =C=C(NC)2, =C=C(H)(CN), =C=N(CN), =C=C(CN)(COOR) or =C(H)(R). In the formula II, each of X and Y is =O, =Se, =Te, =C=O, =C=N(CN), =C=C(CN)2, =C=C(H)(CN) or =C=C(CN)(COOR3), Z is =O, etc., and each of R1 and R2 is alkyl, etc. Each of X-Z in the formulae I, II is divalent and bonds in two directions.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor for forming an electrostatic latent image. More specifically, the present invention relates to an electrophotographic photoreceptor having a layer containing a compound having electron transport ability.

0002

[Prior Art] Conventionally, electrophotographic photoreceptors using organic photoconductors have been studied in various ways because they have advantages such as non-pollution, high productivity, and low cost. It is put into practical use as a photoreceptor for machines. These electrophotographic photoreceptors include laminated and single-layer types, but photoreceptors using organic photoconductors generally have a charge generation layer that generates charges when irradiated with light, and a charge generation layer that transports the generated charges. It has a laminated structure consisting of a transport layer. In this case, the charge transport material used in the charge transport layer is a polymer material such as poly-N-vinylcarbazole, or a low molecular compound such as pyrazoline, hydrazone, or triphenylamine derivative.

However, since all of these charge transport materials have a hole transport ability, most of them employ a developing method in which the surface of the photoreceptor is negatively charged. For this reason, the toner that has conventionally been used in high-speed machines cannot be used, and currently there are few toners with high image quality. Furthermore, when the surface of the photoreceptor is negatively charged in this way, there is a problem that ozone is generated by reaction with oxygen in the air during charging, which not only harms the environment but also deteriorates the surface of the photoreceptor.

On the other hand, a positively charging laminated photoreceptor has been developed in which the layer structure of the photosensitive layer of the laminated photoreceptor is reversed, and a charge transport layer is provided on the lower side and a charge generation layer is provided on the upper side. Since the charging potential is low and the printing durability is poor, the structure is such that a protective layer is further provided on the charge generation layer.

In order to solve the above-mentioned problems, a photoreceptor may be constructed in which a charge transport material having an electron transport ability is used in the charge transport layer and the surface of the photoreceptor is positively charged. Examples of such electron-transporting materials include 2,4
, 7-trinitro-9-fluorenone is known. However, this substance is not useful for all electrophotographic photoreceptors and is carcinogenic, so its use has been discontinued. In addition, there are currently few other useful materials.

[0006]

[Object of the invention] In view of the above-mentioned problems, the present invention has been made to
An object of the present invention is to provide an electrophotographic photoreceptor using a charge transport material having electron transport ability.

Another object of the present invention is to provide a positively charging laminated electrophotographic photoreceptor having excellent electrophotographic performance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of research, the present inventors have found that the objects of the present invention can be achieved by any of the following electrophotographic photoreceptors. That is, in an electrophotographic photoreceptor having a photosensitive layer provided on a conductive support, the photosensitive layer contains one of the compounds represented by the following general formulas (A) and (B) as a charge transport substance. An electrophotographic photoreceptor featuring:

[0009]

[Chemical formula 3]

In the general formula (A),
,=Se,=Te,=C=O,=C=C(CN)2,=
C=N(CN),=C=C(CN)(COOR),=C
=C(H)(CN). Z is divalent =O, =S, =
Se,=Te,=N(R),=C=C(NC)2,=C
=C(H)(CN), =C=N(CN), =C=C(C
N)(COOR),=C(H)(R). Further, A represents the following two substituted or unsubstituted rings, an aromatic ring, or a heterocycle.

In the general formula (B), X and Y are divalent =O, =Se, =Te, =C=O, =C=N (C
N), =C=C(CN)2,=C=C(H)(CN),
=C=C(CN)(COOR3), Z is divalent =O, =
Se, =Te, =C=O, =N(R4), R1 and R2 are alkyl group, alkoxy group, electron-withdrawing group, SCN group, S
It is O2R5. R3, R4 and R5 are an alkyl group or a substituted or unsubstituted benzene ring.

The following compounds are disclosed as examples of the compounds represented by the above general formula (A) or (B) used in the present invention.

These compounds are synthesized according to commonly used synthetic methods.

Compound represented by general formula (A): (Synthesis example A)

[0015]

[C4]

2-phenyl-1,3-indanedione 1
0g (0.045mol) and 9.5g of malononitrile
(0.144 mol) in 500 ml of dry pyridine and refluxed for 25 hours under N2 atmosphere. Pyridine was concentrated to 50 ml under reduced pressure, and the precipitated crystals were collected by filtration. The obtained crystals were recrystallized from acetone. Yield 8.5g
(Yield 60%).

(Exemplary compounds)

[0018]

[C5]

[0019]

[C6]

[0020]

[Chemical 7]

Compound represented by general formula (B): (Synthesis example B)

[0022]

[Chemical formula 8]

Compound (1) 10g (6.0×10▲▼2
mol) and malononitrile 4.3g (6.5×10▲
▼2 mol) in 500 ml of dry pyridine, and
The mixture was refluxed under 2 atmospheres for 30 hours. Pyridine under reduced pressure
It was concentrated to 0 ml, and the precipitated crystals were collected by filtration. The obtained crystals were recrystallized from acetone to obtain the desired product (3). Yield 7.0g (yield 54%) (exemplary compound)

[0024]

[Chemical formula 9]

[0025]

[Chemical formula 10]

[0026]

[Chemical formula 11]

In the electrophotographic photoreceptor of the present invention, examples of the conductive support include a metal pipe, a metal plate, a metal sheet, a metal foil, a conductive-treated polymer film, A1
A polymer film or paper coated with a metal oxide, a quaternary ammonium salt, etc. is used.

In the electrophotographic photoreceptor of the present invention, a photosensitive layer is provided on the conductive support, but the photosensitive layer may have a single layer structure or a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. It may also be from. Further, an adhesive layer may be provided between the conductive support and the photosensitive layer.

The adhesive layer may be formed of resin alone, coated with a low-resistance compound such as tin oxide, indium oxide, or titanium oxide dispersed in resin, or may be formed of aluminum oxide, zinc oxide, silicon oxide, etc. A vapor-deposited film of may also be used. The resin used for the adhesive layer is not particularly limited, but examples include vinylidene chloride-vinyl chloride copolymer, water-soluble polyvinyl butyral resin, alcohol-soluble polyamide resin, vinyl acetate resin, polyvinyl alcohol, nitrocellulose, polyimide resin, etc. It will be done.

The thickness of the binding layer is preferably about 0.01 to 10 μm, particularly preferably 0.01 to 1 μm. When the photosensitive layer is a single layer, the above general formula (A) is contained in the photosensitive layer made of a known material such as polyvinylcarbazole.
, (B) as a sensitizer, or a photosensitive layer containing a known charge generating substance containing a compound represented by the above general formulas (A) or (B) as an electron transporting substance. Examples include things that were made.

On the other hand, when the photosensitive layer is of a laminated type,
The charge generation layer may be obtained by vapor depositing a charge generation substance on a conductive support, or may be formed by applying a coating liquid containing a charge generation substance and a binding resin as main components.

Any known charge generating substance and binder resin can be used. for example,
Charge generating substances include inorganic semiconductors such as Tri-Se, organic semiconductors such as polyvinylcarbazole, bisazo compounds, trisazo compounds, metal-free phthalocyanine compounds, metal phthalocyanine compounds, pyrylium compounds, squarium compounds, and cyanine. Organic pigments such as perylene-based compounds, perylene-based compounds, and polycyclic quinone-based compounds can be used. In addition, as the binder resin, polystyrene, silicone resin, polycarbonate resin, acrylic resin,
Methacrylic resin, polyester, vinyl polymer, cellulose resin, butyral resin, silicone-modified butyral resin, alkyd resin, etc. can be used.

The thickness of the charge generation layer is 0.01 to 10 μm.
The thickness is preferably from 0.05 to 2 μm.

A charge transport layer is formed on the charge generation layer. This charge transport layer is composed of a compound represented by the above general formulas (A) and (B) and a binder resin,
Applying a coating liquid containing the compound represented by the above general formulas (A) and (B), a binder resin, and a suitable solvent as main components onto the charge generation layer using an applicator, bar coater, dip coater, etc. formed by. In this case, the mixing ratio of various compounds and binder resin is 1:100 to 100:
1 is preferred, particularly 1:20 to 20:1.

Any known charge transport substance and binder resin can be used in the charge transport layer. For example, as the binder resin, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, vinyltoluene-styrene copolymer, styrene-modified alkyd resin, silicone-modified alkyd resin, soybean oil-modified alkyd resin, vinylidene chloride-chloride Vinyl resin, polyvinyl butyral, nitrated polystyrene,
polymethylstyrene, polyisoprene, polyester,
Examples include phenol resin, ketone resin, polyamide, polycarbonate, polythiocarbonet, polyarylate, polyhaloarylate, vinyl acetate resin, polystyrene, polyallylethene, polyvinyl acrylate, polysulfone, polymethacrylate, and the like. Further, an electron donating substance may be added to the charge transport layer. Furthermore, an antioxidant and a radical trapping agent may be added to the charge transport layer. The thickness of the charge transport layer is preferably 2 to 100 μm, particularly preferably 5 to 50 μm.

In the electrophotographic photoreceptor of the present invention, a barrier layer may be provided on the conductive support. The barrier layer is effective in preventing unnecessary charge injection from the conductive support, and has the effect of improving image quality. Materials for forming the barrier layer include metal oxides such as aluminum oxide, acrylic resins, phenol resins, polyester resins, polyurethanes, and the like. The barrier layer may be provided below or above the adhesive layer.

[0037]

EXAMPLES The present invention will be explained below using Examples Group A and Group B.

(Group of Examples A) Example A1 A 0.05 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer was provided on a PET film on which aluminum was vapor-deposited, and the following was applied thereon. A charge generation layer (0.5
μm) using a bar coater, 2 g of a solution of 0.16 g of Exemplified Compound A1 dissolved in 10 ml of ethylene chloride (polymer:solvent = 0.75:1) was applied with a doctor blade, and heated at 90°C. Dry for 1 hour, film thickness 20
A μm electrophotographic photoreceptor was prepared. This electrophotographic photoreceptor was tested at +800V and -80V using an electrostatic copying paper tester (EPA-8100 manufactured by Kawaguchi Electric Seisakusho Co., Ltd.).
It was charged to 0 V and exposed to 10 lux of white light, and the amount of exposure until the surface potential was halved was determined and was defined as the sensitivity.

The results are shown in Table A. The method of determining the sensitivity is the same for Example B group.

[0040]

[Chemical formula 12]

Examples A2 to A9 Electrophotographic photoreceptors were prepared in the same manner as in Example A1, except that the compounds shown in Table A were used in place of exemplified compound A1, and the sensitivity was measured in the same manner. The results are shown in Table A.

Comparative Example A (1) An electrophotographic photoreceptor was prepared in the same manner as in Example A1, except that 2,4,7-trinitrofluorenone (TNF) was used in place of exemplified compound A1, and the same procedure was carried out. Sensitivity was measured. The results are shown in Table A.

Comparative Example A (2) Tetracyanoquinodimethane (T
An electrophotographic photoreceptor was prepared in the same manner as in Example A1 except that CNQ) was used, and the sensitivity was measured in the same manner. The results are shown in Table A.

[0044]

[Table 1]

(Group of Examples B) Example B1 A 0.05 μm thick intermediate layer made of vinyl chloride-vinyl acetate-maleic anhydride copolymer was provided on a PET film on which aluminum was vapor-deposited, and the above-mentioned Charge generation layer (0.5 μm) consisting of bisazo compound BA and polyvinyl butyral (bisazo compound:butyral=3:1)
was applied using a bar coater, and exemplified compound B2 was applied thereon;
A solution of 0.16g dissolved in 10ml of ethylene chloride (
2 g of polymer:solvent=0.75:1) was applied with a doctor blade and dried at 90° C. for 1 hour to prepare an electrophotographic photoreceptor with a film thickness of 20 μm.

The results are shown in Table B.

Examples B2 to B5 Example B1 except that compounds shown in Table B were used in place of exemplified compound B2.
An electrophotographic photoreceptor was prepared in the same manner as above, and the sensitivity was measured in the same manner. The results are shown in Table B.

Comparative Example B (1) An electrophotographic photoreceptor was prepared in the same manner as in Example B1 except that 2,4,7-trinitrofluorenone (TNF) was used in place of exemplified compound B2, and the same procedure was carried out. Sensitivity was measured. The results are shown in Table B.

Comparative Example B (2) Tetracyanoquinodimethane (T
An electrophotographic photoreceptor was prepared in the same manner as in Example B1 except that NCQ) was used, and the sensitivity was measured in the same manner. The results are shown in Table B.

[0050]

[Table 2]

As is clear from Tables A and B, the examples of the present invention exhibit positive charging sensitivities that are sufficiently within the practical range.

[0052]

[Effects of the Invention] The compound of the present invention has an electron transport ability and can provide a practical sensitivity for positive charging.

Claims (2)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (A) as a charge transport substance. Photoreceptor. [Formula (A)] [In the general formula (A), X and Y are divalent =O, =Se, =Te, =C=O, =C=C with bonds open in two directions.
(CN)2,=C=N(CN),=C=C(CN)(C
OOR),=C=C(H)(CN). Z is a divalent =O, =S, =Se, =Te, with bonds open in two directions.
=N(R), =C=C(CN)2, =C=C(H)(C
N),=C=C(CN)2,=C=C(CN)(COO
R), =C(H)(R). Further, A represents the following two substituted or unsubstituted rings, an aromatic ring, or a heterocycle. ] 2. An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (B) as a charge transport substance. Photoreceptor. [In the general formula (B), X and Y are divalent =O, =Se, =Te, =C=O, =C=N with bonds open in two directions.
(CN),=C=C(CN)2,=C=C(H)(CN
), =C=C(CN)(COOR3), Z is divalent =O with bonds open in two directions, =Se, =Te, =C=O,
=N(R4), R1 and R2 are an alkyl group, an alkoxy group, an electron-withdrawing group, an SCN group, and SO2R5. Said R3
, R4 and R5 are an alkyl group or a substituted or unsubstituted benzene ring. ]