JPS61103155A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form an electrophotographic sensitive body prevented from deterioration of acceptance potential, high residual potential, susceptibility to temp. and humidity, and deterioration of sensitivity, and stabilized in acceptance potential and residual potential at the time of repeated uses by using a specified squarinic acid deriv. as a material for an electrostatic charge generating layer. CONSTITUTION:A charge transfer layer, the charge generating layer, and a surface protective layer low in resistance are successively laminated on a conductive substrate and the charge generating layer is formed by dispersing the squarinic acid represented by formula I as the charge generating material, preferably, in an amt. of 20-50wt% into a binder resin, such as polyvinyl butyral or various other resins. A preferable particle diameter of said deriv. is in the range of 0.05-1mum.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

[Prior art]

Conventionally, there have been many forms in which a charge generation layer is laminated as a lower layer of a charge transport layer as an f+1-1 structure of a laminated organic photoreceptor. Since most of the charge 1::7 transport layers commonly found at present have hole transport properties, it is necessary to use a photoreceptor having such a configuration with negative charging. For this reason, it has an impact on the photoreceptor, such as generation of a high concentration of ozone due to negative charging and uneven charging of the Kontron (it has had serious drawbacks).

In order to eliminate this drawback, a charge generation layer is laminated as an upper layer of the charge transport layer, and used with positive charging.In order to improve mechanical strength, deterioration, etc., a low resistance surface protection layer is laminated as the top layer. A similar configuration was attempted.

However, a photoreceptor with such a configuration does not have sufficient chargeability, resulting in only a low contrast potential, or even if it has sufficient chargeability, light attenuation is insufficient and the residual potential is high, and the temperature and humidity are high. There are various drawbacks, such as changes in the charging position and residual potential due to changes in the charging position, changes in the charging position and residual potential during repeated use, and a large decrease in sensitivity compared to before applying the surface protective layer. had.

[Purpose of the invention]

The object of the present invention is to provide an electrophotographic photoreceptor free from such drawbacks.
That is, it is an object of the present invention to provide an electrophotographic photoreceptor that prevents a decrease in charging potential, a high residual potential, the influence of temperature and humidity, and a decrease in sensitivity, and has a stable charging potential and residual potential during repeated use.

[Structure of the invention]

The object of the present invention can be achieved by using a specific squaric acid derivative as a material for the charge generation layer. A further object of the present invention is to provide a low-resistance surface protective layer made of fine particles of a specific conductive metal oxide dispersed in an insulating resin on a charge generation layer using a specific squaric acid derivative. It can be achieved.

In the present invention, a charge transport layer, a charge generation layer, and a low resistance surface protection layer are sequentially laminated on a conductive support, and a squaric acid derivative represented by the following structural formula (1) is separated in the charge generation layer. This is an electrophotographic photoreceptor characterized in that it has two sides.

Supports with conductive surfaces used in the present invention include drums and sheets of metals such as aluminum, copper, iron, zinc, nickel, etc.;
Vapor deposition of metals such as platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium, etc., vapor deposition of conductive metal compounds (e.g., In1O3, SnO□), lamination of metal foils, or carbon black, conductive metal compounds (e.g. ,
I'nz03.5b20. -5nO□, 5n02, Ti
0x) Drum-shaped, sheet-shaped, plate-shaped paper, plastic, glass, etc., whose surfaces are electrically conductive treated by dispersing powder, metal particles, etc. in a binder resin and applying the coating, are used.

The charge transport layer used in the present invention includes charge transport materials such as pyrene, N-ethylcarbasol, N-isopropylcarbasol, and 2,5-bis(P-diethylaminophenyl)-1,3,4-oxane. Diazole, l-phenyl-3-(P-diethylaminostyryl)-5-(P-
diethylaminophenyl)pyrazoline, ■-[pyridyl-(2)]-3-(P-diethylaminostyryl)-5
-(P-diethylaminophenyl)pyrazoline, l-[
Quinolyl-(2)] -3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, triphenylamine, N,N'-"diphenylN-
N'-bis(3-methylphenyl)-[1,l'-biphenyl]-4,4"-diamine, 4-diethylaminobenzaldehyde-1, l-diphenylhydrazone, 4,
4"-benzylidene-bis(N,N'-diethyl-m-
) luidine, poly-N-vinylcarbazole, halogenated holy N-vinylcarbazole, polyvinyl pyrene, polyvinylanthracene, polyvinyl ataridine poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, etc. .

These charge transport materials can be used alone or in combination of two or more. Charge transport materials are not limited to those described here. Binder resins used in the charge transport layer include general-purpose resins such as acrylic resin, methacrylic resin, polystyrene, polyester, polyarylate, polysal 7one, and polycarbonate, and tag transport polymers such as poly-N-vinylcarbazole. can be used. Note that an adhesive layer may be provided between the conductive support and the charge transport layer.

The charge generation layer used in the present invention uses the above-mentioned squaric acid monoconductor as a charge generation material, and adds it to a binder resin in an amount of, for example, 5% to 90% by weight, preferably 20% to 50% by weight. It is dispersed. The particle size of the squaric acid derivative is suitably 0.02 μm to 3 μm, preferably 0.05 μm to 1 μm. Electron 1: As the binder resin for the generation layer, polyvinyl butyral, poly])'F vinyl acid, polyester, polycarbonate,
Various resins such as phenoxy resin, acrylic resin, polyacrylamide, polyimide, polyvinylpyridine resin, casein, polyvinyl alcohol, and vinylcarbazole are used.

The low-resistance surface protective layer used in the present invention is a layer in which fine particles of a conductive metal oxide are dispersed in an insulating resin.
Fine particles exhibiting a gray or blue-white color and an average particle diameter of 0.3 μm or less, preferably 0.1 μm or less are suitable;
For example, antimony oxide, tin oxide, titanium oxide, indium oxide, a solid solution of tin oxide and antimony, or a solid solution of antimony oxide, etc. alone or a mixture thereof, or a single particle containing a mixture of these metal oxides, or a coated material. can be mentioned. Among them, tin oxide and antimony, a solid solution of antimony oxide, or tin oxide can lower the electrical resistance and make the protective layer substantially transparent.
'), A-f, t L <i@b"1tl-'y
('*' No. 457-30847, JP-A-57-12
83/I, see '1 Publication).

It is desirable that the protective layer has an electrical resistance of 10 9 to IO+4Ω·r,m. Electrical resistance is 10”Ω・
When it is more than cn+, l)i, t3'? The potential rises, resulting in a copy with a lot of fog, and if it becomes less than 10<9>Ω·cm, the image becomes blurred and the resolution decreases.

In addition, the protective layer does not have to be constructed so as not to substantially obstruct the passage of light used for imagewise exposure). - If the particle size of the conductive metal oxide used is too large, the protective layer becomes opaque, resulting in a dull feeling and a decrease in image density. The particle size is the wavelength of the light used for image exposure (0.42 to 0.8 μm)
Below, the particle size is preferably one-half or less, that is, 0.3
It is desirable to use particles with a size of .mu.m or less, preferably 0.1 .mu.m or less.

As the insulating resin, it is desirable to use an electrically insulating transparent resin whose electrical resistance does not easily change due to changes in humidity or temperature. Examples of insulating resins include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, and polyacrylamide. It is preferably used in terms of stability.

The fine particles of conductive metal oxide are 20% of the insulating resin.
A dispersion of up to 4:) 60% by weight is desirable.

If it is less than 20% by weight, the electrical resistance will be 101 Ω·cm or more, and if it is more than 60% by weight, the film strength of the protective layer will be significantly reduced. Therefore, the dispersion is preferably carried out in a range of 30% to 50% by weight.

Further, a charge injection blocking auxiliary layer may be provided on the noodle between the low resistance surface protective layer and the charge generation layer. Examples of the auxiliary layer forming material include coupling agents such as silane coupling agents and titanium coupling agents, organometallic compounds such as organic zirconium compounds and organic titanium compounds, and general-purpose resins such as polyester and polyvinyl butyral.

The appropriate film thickness of each layer is 5 μm to 40 μm for the charge transport layer, preferably 8 μm to 30 μm, and 5 μm to 30 μm for the charge generation layer.
m or less, preferably 0.1 μm to 3 μm, and the low resistance surface protective layer has a thickness of 0.5 μm to 20 μm, preferably 1 μm to 10 μm.
μm is appropriate.

〔Example〕

Examples of the present invention are shown below.

Example 1 A photoreceptor was prepared by sequentially laminating a charge transport layer, a charge generation layer, and a surface protection layer made of the following materials on an aluminum substrate.

Charge transport layer polyester resin 50 parts by weight (20 parts by weight)
μ) (Toyobo: Byron 200) 2.5-bis (P
-diethylaminophenyl) -1,3,4-oxadiazole 50 parts by weight Charge generation layer Squaric acid derivative (1μ) (Structural formula (+)) 30 parts by weight Polyisobutyl methacrylate (DuPont: Elvacite 2045) 70 parts by weight Surface protective layer Tin oxide powder: 45 parts by weight Polyurethane: 55 parts by weight This photoreceptor was subjected to a commercially available electrostatic copying test in an environment of 5096 RI-1 at 20°C using electrostatic paper manufactured by Kawaguchi Electric. Anarai +1'-5P-4
28), a +6 kV corona discharge was performed to positively charge the sample, and the surface potential was measured after being left in a dark place for 1 second, and it was found to be 100 OV. Immediately thereafter, tungsten light of 5 lux was irradiated for 3 seconds to determine the light weight Ez required to reduce \'nap by half.

Furthermore, after this, the surface potential was further attenuated by irradiating light of 200 lux for 0.5 seconds, and the surface potential at that time was determined as residual potential: RP.

This measurement was carried out 1,000 times in succession, and ■ the 1st cycle and 2) the 1000th cycle. ,,the difference in RP is △■,. ,
(C), cycle stability was expressed as ΔRP (C).

In addition, similar measurements were carried out at 10°C and 20% RH and at 30°C.
It was carried out under the environment of 80% R1 ([cycle [] and 1
The difference between Vnup and RP at the 000th cycle is ΔVOD
Environmental safety was expressed as P (E) and △RP (E).

The various measured values during the tree-killing process are shown below.

Vnop: 100OV E! 4: 1.8 Lux・sec RP: 60V △Voop (C): 70V △RP(C
): 30VΔVoop ([i): 50V
ΔRP(E): 20V, that is, it can be said that it has sufficient chargeability and sensitivity, as well as excellent cytal stability and environmental safety.

Comparative Example I Example 1 except that β-type copper phthalocyanine was used instead of the squaric acid derivative in the charge generation layer in Example 1.
A photoreceptor was prepared in the same manner as above, and the same measurements were performed, and the following values were obtained.

V,, p: 650V E'A Near, 0 Lux・sec RP: 80V △ Voop (C): 200V Δ
RP (C): 30VΔVoop (B): 2
00V ΔRP(L':): 40V 'Charging property is low, and it shows that there are problems in both cycle and environment quality.

Examples 2 to 6 Photoreceptors were prepared in the same manner as in Example 1 except that the binders in the charge transport layer and charge generation layer in Example 1 were changed to the following combinations, and measurements were conducted. It exhibited excellent chargeability and sensitivity, as well as excellent cycle and environmental stability.

Example 7 A photoreceptor was prepared and measured in the same manner as in Example 1, except that the surface protective layer in Example 1 was changed to 40/60 parts by weight of titanium oxide/polyurethane resin. It exhibited stable characteristics similar to those of the photoreceptor of Example 1.

Vnop: 950V E'//2: l, 3 lux・sec RP: 50V ΔVnop (C): 80 V ΔRP (
C): 20VΔVnop (E): 90V
ΔRP (E): 30 V [Effects of the Invention] According to the present invention, an electrophotographic photoreceptor having excellent chargeability, sensitivity, cycle stability, and environmental stability can be obtained.

[Brief explanation of the drawing]

1 to 4 are sectional views of specific examples of the electrophotographic photoreceptor of the present invention. 10...Low resistance surface protective layer, 11...
Charge generation layer, 12... Charge transport layer, 13...
... Conductive support, ■4 ... Conductive metal oxide, 15 ... Charge generating material, 20 ...
Adhesive layer, 30...Charge injection blocking auxiliary layer. Figure 1 Figure 2 Figure 3! ! S! 1 Figure 4

Claims (2)

[Claims] (1) A charge transport layer, a charge generation layer, and a low resistance surface protection layer are sequentially laminated on a conductive support, and the charge generation layer contains the following structural formula (I) ▲Mathematical formula, chemical formula, table, etc.▼(I ) An electrophotographic photoreceptor characterized by dispersing a squaric acid derivative represented by: (2) The low-resistance surface protective layer consists of a layer in which fine particles of a conductive metal oxide are dispersed in an insulating resin, and the conductive metal oxide has an electrical resistance of 10^9 Ω·cm or less and an average particle size. 0
．． The electrophotographic photoreceptor according to claim (1), characterized in that the particles are 3 μm or less.