JPS61110146A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To eliminate pollution and to improve productivity, reliability, etc. by providing a photosensitive layer consisting of lead oxide, quinoneimine dye, org. charge transfer material and binder on a conductive substrate thereby providing an electrophotographic sensitive body. CONSTITUTION:The photosensitive layer is provided to about 5-5mum by coating a coating liquid consisting of the zinc oxide, quinoneimine dye, org. charge transfer material and binder on the conductive substrate such as the substrate of Al, Znor the like which itself has conductivity or the substrate made by coating Al, etc. to plastic by a vacuum deposition method, by which the electrophotographic sensitive body is formed. A barrier layer having >=10<7>OMEGAcm volume resisti-vity and <=5mu thickness may be provided between the conductive substrate and the photosensitive layer. A protective layer or insulating layer having >=10<11>OMEGAcm surface resistivity may be provided on the photosensitive layer as well.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is sensitive to both positive and negative charge polarities. This invention relates to a so-called bipolar electrophotographic photoreceptor. In particular, the present invention relates to an electrophotographic photoreceptor using a composite material of zinc oxide and an organic photoconductive material (OPC).

BACKGROUND OF THE INVENTION OPG, which is non-polluting and low-cost, is increasingly used as a photosensitive material for electrophotography. Traditionally O
Although PC had some drawbacks in sensitivity, durability, and environmental stability, these drawbacks have been rapidly improved in recent years. o
PCs are widely applied not only to general copying machines but also to laser beam printers, copying machines using laser light sources, microreader printers, facsimile printers, and color copying machines. Therefore, OPC is also becoming more sensitive, expanding the sensitive wavelength range (compatible with long wavelength semiconductor lasers), increasing lifespan, improving image quality, improving quality, lowering costs, mass production, non-pollution, and safety. Demand is increasing. In particular, in systems that use the so-called reversal development process, such as image scan laser beam printers and negative-positive microreader printers, as shown in Fig. It is necessary to perform a charging process.

Under such conditions, with a negative polarity OPC, it is normal to carry out negative charging and transfer positive charging, but the positive charge imparted to the OPC drum by positive charging during transfer is not erased by post-exposure. Therefore, it remains as a residual charge, causing potential unevenness (image unevenness). Therefore, in order to eliminate this potential unevenness, complicated adjustment of transfer charging conditions, secondary charging conditions, grid, exposure, development conditions, etc. is required. A photoreceptor used under such conditions is desired to have bipolar sensitivity. In this case, the above-mentioned problem does not occur at all.

Examples of bipolar photoreceptors include a single layer (molar layer) type as shown in Figure 2, and a composite type as shown in Figure 3, both of which have unipolar charge carriers. move in different directions, and currently there are problems with memory caused by carrier traps, residual potential at the composite layer interface, etc., and it is difficult to obtain products with satisfactory characteristics.

If a photosensitive layer in which carriers of both positive and negative polarity can move is selected, an electrophotographic photoreceptor with good polarity can be obtained without causing carrier traps as described above.

Examples of such photoreceptors include charge transporting substances such as hydrazine groups and pyrazoline as positive carrier carriers, and negative carriers such as Toshite, CdS, etc. in the same photosensitive layer.
Examples include PVK-TNF (polyvinylcarbazole-trinitrofluorenone), but it is highly toxic, requires measures to be taken back from the market, and is also undesirable from the standpoint of work safety.

Problems to be Solved by the Invention An object of the present invention is to provide an electrophotographic photoreceptor having excellent characteristics and sensitivity to both polarities.

That is, the objective is to provide an electrophotographic photoreceptor that is pollution-free, low cost, productive, reliable, and of high quality.

Organic photoconductors (OP
An object of the present invention is to provide a novel electrophotographic photoreceptor containing C) and zinc oxide as main components.

Means and Effects for Solving the Problems The present invention provides an electrophotographic method comprising a photosensitive layer comprising zinc oxide, a quinone imine dye, an organic charge transport substance, and a binder on a conductive substrate. Consists of a photoreceptor.

Zinc oxide is an electron carrier and the organic electrolytic transport material is a hole carrier. Quinoneimine dyes act as sensitizers.

FIG. 1 explains the operation of the photoreceptor of the present invention when it is negatively charged and positively charged.

The quinone imine dyes used in the present invention include (1) azine dyes, (2) oxazine dyes, (
3) Includes three groups of thiazine dyes.

Exemplary dye azine dye 4 No. 1 Safranin T (CI No. 841) + 1o,
2 Supramin Blue EC No, 3 Wool Fast Blue BL (CINo,
833) Oxazine Dye No. 4 Melt Trouble-(CINo, 909) No.
, 5 is Russiania (C1)1o883)NO0
6 Sirius Splat Blue FFRLN007 Sirius Splat Blue FFBNo, 8 Mechi L/7 Blue (
CINo, 922) Ma, 9 Methylene Gly-7 (C
INaJ24) No, IO brilliant alizarin blue-3R (CINo, 931), and the like.

Examples of organic hole transport materials used in the present invention include:
Pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N-phenylhydrazino-3
-Methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-〇-methylidene-8-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino-3 -Methylidene-1O-ditylphenoxazine, P-diethylaminobenzaldehyde.

N-diphenylhydrazone, P-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone, l, 3.3 Trimethylindolenine-aldehyde-N, N - hydrazones such as diphenylhydrazone, P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone,
2.5-bis(P-diethylaminophenyl)-1,3
,4-oxadiazole, 1-phenyl-3-(P-diethylaminostyryl)-5-(P-diethyl7minophenyl)pyrazoline, 1-[quinolyl(2)]”-
3-(P-diethyl7-minostyryl)-5-(P-diethylami/)pyrazoline, 1-[pyridyl(2
)] -3-(P-diethylaminostyryl) -s
-(p-diethyl7minophenyl)pyrazoline, 1-
[6-Medoxybilidyl (2)] -3-CP-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[Levidyl (2)] -3-
CP-diethylaminostyryl) -5-(P-diethylaminophenyl)pyrazoline, l-[pyridyl (2)
]-3-(-diethylaminostyryl)-4-methyl-
5-(P-diethylaminophenyl)pyrazoline, 1-
[Pyridyl (2)] -3-(α-Methyl-P-diethylaminostyryl) -5-(P-jethyruamino 2enyl)pyrazoline, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl- 5-(P-diethylaminophenyl)pyrazoline, 1-phenyl-3-(α-
benzyl-P-diethyl 7-minostyryl) -5-(P
- Pyrazolines such as diethylaminophenylpyrazoline and spiropyrazoline, 2-(P-diethyl7minostyryl) -e -diethylaminobenzoxazole, 2
Oxazole compounds such as -(P-diethyl 7-minophenyl)-4-(P-diethyl 7-minophenyl) -5-(2-chlorophenyl)oxazole, thiazoles such as 2-(P-diethylaminostyryl)-8-diethylaminobenzothiazole triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1.1-bis(4-N,N-
diethylamino-2-methylphenyl)hebutane, 1
, polyarylalkane such as , 1,2.2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine , poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, and the like. Examples of binders include polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin,
Methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenolic resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or a copolymer containing two or more repeating units of these resins, such as styrene-butadiene copolymer, styrene -acrylonitrile copolymer, styrene-maleic acid copolymer, etc. Commercially available zinc oxide may be used, but 0.1 to 5 t, particularly preferably 0.1 to 5 t.
It is preferable to have a diameter of 1 to 1.0 degrees.

When forming layers by coating, dip coating method,
This can be carried out using a coaching method such as a spray coaching method, a spinner coaching method, a bead coaching method, a Meyer bar coaching method, a plaid coaching method, a roller coaching method, a curtain coaching method, or the like.

The photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer can be prepared using a substrate having a conductive layer that is itself conductive, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum,
Chromium, titanium, nickel, indium, gold, platinum, etc. can be used, as well as aluminum, aluminum alloys, indium oxide, tin oxide, and indium oxide.
Plastics having a layer formed by vacuum evaporation of a soot oxide alloy, etc., such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate,
Acrylic resin, polyfluoroethylene, etc., conductive particles such as carbon black.

A substrate coated on plasti-7 together with a suitable binder such as silver particles, a substrate made of plasticine or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

The appropriate thickness of the photosensitive layer is about 5 to 50 mm, preferably about 15 to 25 mm.

A subbing layer with barrier and adhesive functions can be provided between the conductive layer and the photosensitive layer, and casein.

Polyvinyl alcohol, nitrocellus, ethylene
Acrylic acid copolymers, polyamides such as nylon 6,
Nylon 66, nylon 610. Copolymerized nylon, alkoxymethylated nylon, etc.

It can be formed from polyurethane, gelatin, aluminum oxide, etc. The film thickness is 5 to 3 or less, preferably 0.5 to 3
The end is appropriate. In order for the barrier calendar to perform its function, it is desirable that the distance is 1070 cm or more, and dyes, pigments, organic charge transport materials, etc. are generally exposed to ultraviolet rays, ozone,
It is susceptible to dirt from oil etc. and chips from metal etc., and a protective layer (insulating layer) may be provided if necessary.In order to form an electrostatic latent image on this protective layer, the surface resistivity is 8 The protective layer used in the present invention is preferably 100 or more, polyvinyl butyral, polyester, polycarbonate,
A solution in which a resin such as acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer is dissolved in a suitable organic solvent is applied onto the photosensitive layer. , can be dried and formed. At this time, the thickness of the protective layer is generally 0°05
-20 liters, preferably 0.2-5 liters. An example will be shown below in which a UV absorber or the like may be contained in this protective layer.

Example 1 A liquid having the following composition was dispersed in a magnetic ball mill for 12 hours.

Photoconductive powdered soybean lead 100 parts by weight Safranin T
(CINo, 841) l ttP-diethylaminobenzaldehyde-α-naphthylphenylhydrazone 100 Acrylic-styrene resin 100//(MS-200, manufactured by Nippon Steel Chemical) Methylseronlupe 80//Monochlorobenzene 30//Put the dispersion through a 20p filter After filtering with
Coated on a mm aluminum cylinder by dipping method and heated at 100°C.
The layer was dried for 60 minutes to obtain a photosensitive layer of 20 tiles. Potential characteristics and image printing were performed using a Canon Microreader PC printer 70.

Primary charging -450 final A (constant current), image exposure halogen lamp 81 ux, sec, development negative toner, transfer charging +400 final A (constant current) Also, as a comparative example, P
-Diethylaminobenzaldehyde-[alpha]-naphthylphenylhydrazone was not used, but the same procedure as in Example 1 was repeated to obtain 20 photosensitive layers.

The evaluation results were as follows.

Example 1 Comparative example Dark potential (VD) -430v -40
0v half-attenuation light amount (sensitivity) 4.11. s 4.5
．． jL, s Bright area potential (VL) -100v
-100V Image unevenness: 0x (influence of reverse charging) Evaluation was also carried out using -order charging: +500 JLA, image exposure using a halogen lamp of 81 ug, sec, developing positive toner, and transfer charging: -400 final A.

Example 1 Comparative example Dark potential (VD) + 400v +
380v half-attenuation light amount (sensitivity) 4.3 sentences, J - Bright area potential (VL) + 100 meters - Image unevenness 〇 - (influence of reverse charging) Example 2 A liquid with the following composition was dispersed for 12 hours using a magnetic ball mill. I did it.

Photoconductive zinc oxide 100 parts by weight Supramin Blue EG 1tt (Exemplary dye No. 2) P-diethylaminobenzaldehyde-α-naphthylphenylhydrazone 100 PMMA resin (
J-8H1 Seiko Kagaku) 100//Methyl Cellosolve 60//.

Monochlorobenzene 30// After filtering the dispersion using a zO island rough filter, the diameter is 60 mm + the length is 250 m.
The photoreceptor was coated on an aluminum cylinder with a wall thickness of 0.5 mm by a dipping method and dried at 100° C. for 60 minutes to obtain a photoreceptor weighing 18 g.

Canon Microreader Printer PC Printer 7
Potential characteristics and image formation were performed at 0.

-Next charge -450 lux A (constant current), image exposure ゛halogen lamp 8 fL ux, sea, development negative toner, transfer charging +400 pot A (constant current) Also, as a comparative example, the same as the comparative example in Example 1 I used something. The evaluation results were as follows.

Example 2 Comparative example Dark potential (VD) -420v -40
0v half-attenuation light amount (sensitivity) 3.91. s 4.
5 fL,s Bright area potential (VL) JOv
-100v compensation unevenness O× (influence of reverse charging) Also, -order charging +500. A, image exposure halogen lamp 8 nux, sec, development positive toner, transfer charging -400 end A Example 2 Comparative example Dark area potential (VD) + 400v +
380v half-attenuation light amount (sensitivity) 4.1 viewing 4 - Bright area potential (VL) +110mm - Image unevenness
O- (Influence of reverse charging) Example 3 Styrene resin (HF-55,
Nippon Steel Chemical Co., Ltd.) was dissolved in toluene to a viscosity of 25 cps, and applied to a thickness of 1 wire by spraying at 80°C.
Drying was performed for 5 minutes. For the samples of Examples 1 and 3, a Canon Mini Copier PC-20 was modified to have composition plus charge, development negative toner, and transfer plus charge, and a 3,000-sheet durability test was conducted (negative charge is also possible, but positive charge is more durable). Furthermore, as a comparative example, a durability test of 3,000 sheets was conducted on the sample of the comparative example in Example 1 using a PC-20 machine with composition negative charging, development positive donor, and transfer negative charging (comparative example has sensitivity to positive charging). )
.

As a result, it was found that the samples of Examples 1 and 3 had significantly less deterioration, and the durability of the samples provided with a protective layer was further improved. This is because the amount of ozone generated by positive charging is
This is thought to be due to the fact that the charge is 115 to 1/10 compared to a negative charge.

Durability of 3000 sheets of image Example 3 Example 1 Comparative example VO decrease -20v -50-100vV
L7 ypu +20v + 40v +
70v Image fog OOΔ × Slight fog Density decrease Oo × Example 4 Example 1 except that a 0.5% barrier layer was provided between the aluminum cylinder substrate and the photosensitive layer.

The barrier layer was made of polyamide (CM-8000, manufactured by Toshi), the solvent was methanol, the viscosity was 10 cps, and the coating was done by the dipping method.

The evaluation results were as follows.

Example 4 Comparative example Dark potential (VD) -480v -400
v half-attenuation light amount (sensitivity) 3.8, s 4-51 +s
Bright area potential (VL) -110v -10
0v contrast 370ma 300ma (
(VD-VL) Furthermore, a similar study was conducted with negative charge as positive.

Example 4 Comparative example Dark potential (VD)' + 450v +
380v half-reduced sight (sensitivity) 4.0 sentences, s - Bright area potential (VL) + 110ma - Contrast 340- (VD-VL) Further improvement of acceptance potential (VD) was observed by providing a barrier layer. , resulting in contrast potential (VO-VL)
This contributed to increased thickness, increased image density, and reduced fog.

Next, the dyes exemplified as quinone imine dyes were tested in the same manner as in Example 1, corresponding to each example, and good bipolar photoreceptors were obtained in all cases.

As described in detail of the invention, a bipolar electrophotographic photoreceptor has been strongly desired due to its operation and stability of performance, but it has not been possible from the viewpoints of sensitivity, productivity, safety, cost, etc. Desired products have not been developed.

However, by combining a quinoneimine dye and an organic charge transporting material with zinc oxide, we are able to provide electron transport properties not found in conventional organic photoreceptors and durability stability not found in conventional zinc oxide, resulting in an overall superior product. It has become possible to provide a bipolar electrophotographic photoreceptor that has never been seen before.

[Brief explanation of drawings]

Claims (3)

[Claims] (1) Zinc oxide, quinoneimine dye, on a conductive substrate,
An electrophotographic photoreceptor comprising a photosensitive layer comprising an organic charge transport substance and a binder. (2) The electrophotographic photoreceptor according to claim 1, wherein a barrier layer having a volume resistivity of 10^7 Ωcm or more and a thickness of 5 μm or less is provided on the conductive substrate. (3) The electrophotographic photoreceptor according to claim 1 or 2, wherein the uppermost layer is provided with a protective layer or an insulating layer having a surface resistivity of 10^1^1 Ω or more.