JPS5872149A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To improve filming characteristic, sensitivity and durability by containing a specific pyrazoline compd. in a photoconductive layer (more particularly the charge transfer layer of laminated type photoconductive layers). CONSTITUTION:The photoconductive layer contg. the pyrazoline compd. expressed by the formula[R1, R2 are H, alkyl, (substd.) aralkyl, (substd.) aryl, said substitutents are OH, halogen, CN, N(CH3)2, etc., R3-R6 are (substd.) alkyl, (substd.) aralkyl, (substd.) aryl, R3 and R4, R5 and R6 may form cyclic amino groups altogether, said substituents are alkyl, 2-hydroxy alkyl, CN, etc., and R7-R10 are H, halogen, alkyl, alkoxy]is formed on a conductive substrate. More particularly, said layer is contained as a charge transfer material in a charge transfer layer. Thus the photoreceptor which is stable against environmental changes and gives superior toner images is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a novel organic photoconductive substance comprising a Hiropizzoline compound.

Conventionally, non-photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or quickly dissipating the charge when irradiated with light. On the other hand, it has various drawbacks. For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure.
In particular, when the ambient temperature exceeds 40° C., crystallization becomes significant, resulting in drawbacks such as a decrease in chargeability and the appearance of white spots on both sides. Furthermore, selenium-based photoreceptors and cadmium sulfide-based photoreceptors have the disadvantage that stable sensitivity and durability cannot be obtained when used under high humidity over time.

Zinc oxide photoreceptors still require the sensitizing effect of sensitizing dyes such as rose bengal, but these sensitizing dyes cause charging deterioration due to corona charging and photobleaching due to exposure light, so it may take a long time. It has the disadvantage that it cannot provide a stable distance of 6 m over a long period of time.

On the other hand, various organic photoconductive polymers including polyvinylcarbazole have been proposed, but these polymers are superior in terms of film formability and light weight compared to the above-mentioned inorganic photoconductive materials. However, it has been difficult to put it into practical use to date because sufficient film formation properties have not yet been achieved, and inorganic photoconductive materials have been lacking in terms of sensitivity, durability, and stability against environmental changes. This was because they were inferior in comparison. Additionally, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat. No. 3,837,851, etc.,
Low-molecular organic photoconductive materials such as 9-styrylanthracene compounds described in JP-A-94828 and JP-A-51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductive materials can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers.
It cannot be said that the sensitivity is sufficient.

An object of the present invention is to provide a new electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages.

Another object of the present invention is to provide novel organic photoconductive materials.

Another object of the present invention is to provide a compound suitable for a charge transport material used in photosensitive photosensitive material 1-, which has a laminated structure of a charge generation layer and a charge transport layer.

This object of the present invention is achieved by an electrophotographic I-prefecture light material having 1- containing a pyrazoline compound represented by the following general formula (1).

General formula (1) In the formula, IILl and Shima are an alkyl group (especially preferably an alkyl group having 1 to 4 carbon atoms) such as a methyl group, an ethyl group, a propyl group, a butyl group, or an amyl group. ,
It represents an aralkyl group such as a benzyl group, a phenethyl group, or a naphthylmethyl group, or an aralkyl group such as a phenyl group or a naphthyl group. These aralkyl groups and aryl groups can be substituted with a hydroxyl group, a chlorine atom, a halogen atom such as a bromine BJ1 atom, a cyano group, a dimethylamino group, a diethylamino group, a dipropylamino group, a diphenylamino group, a dibenzylamino group, etc. Amino group, methyl group, ethyl group,
Alkyl groups such as propyl and butyl groups, methoxy groups,
ORs which may be substituted with an alkyl group such as an ethoxy group, a propoxy group, a butoxy group, etc., 几-1
RI and f'L are substituted or unsubstituted alkyl groups (e.g., methyl group, ethyl group, propyl group, butyl group, amyl group, octyl group, 2-hydroxyethyl group,
3-hydroxyethyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-N,N-dimethylaminoethyl group,
2- N, N-diethylaminoethyl group, 3- N, N
-diethylaminopropyl group, 3-chloropropyl group, 4- and do-4xybutyl group, 3-methoxybenzyl group,
2-ethoxyethyl group, 3-ethoxypropyl group, etc.)
, substituted or unsubstituted aralkyl groups (e.g., benzyl group, phenethyl group, α-naphthylmethyl group, β-naphthylmethyl group, 4-methylbenzyl group, 4-methoxybenzyl group, 2-chlorobenzyl &, 2,4 .6-dolichlorobenzyl group, 3-hydroxybenzyl group, 3-cyanobenzyl group, 2,6-dichloro-4-methylbenzyl group, 3-nitrobenzyl group, etc.) or substituted or unsubstituted aryl group (e.g. , phenyl group, tolyl group, xylyl group, biphenyl group, α-naphthyl group, β-naphthyl group, 4-methoxyphenyl group, 4-ethoxyphenyl group, 2-chlorophenyl-!, 2,4.6-) IJ
Chlorophenyl group, 2.6-cyclo-4-methylphenyl group, 3-cyanophenyl group, 4-hydroxyphenyl: ll1p< 3-nitrophenyl group, 4-N, N
-dimethylaminophenyl group, 4-N,N-diethylaminophenyl group), and R3 and R4 and R5 and R. can be formed.

R,,,R,,R,andR,・represent a hydrogen atom, a halogen atom (e.g., chlorine atom, bromine atom, etc.), an alkyl group (e.g., methyl group, ethyl group, propyl group, butyl group, amyl group) , octyl group, etc.) or alkoxy group (
For example, methoxy group, ethoxy group, propoxy group, butoxy group, etc.).

Specific examples of the pyrazoline compound represented by the general formula (1) are listed below.

Compound example (1) (10) ((2) (13) ti (18) (19) 0's (21) (23) (24)H @)H (26) (27) Represented by general formula (1) The electrophotographic photoreceptor containing the birazolysi-based compound can be applied to any type of electrophotographic photoreceptor using an organic photoconductive substance, but preferred types include 1) an electron-donating substance and an electron-accepting substance; A charge transfer complex is formed by a combination of

2) An organic photoconductor sensitized by adding a dye.

3) Pigment dispersed in a hole matrix.

4) Functionally separated into charge generation layer 1- and charge transport layer.

5) With dye! The main components are a eutectic complex consisting of Li fat and an organic photoconductor.

6) An organic or non-self-contained charge-generating material is added to a cargo transfer complex.

etc., among which types 3) to 6) are desirable.

In the case of a 4) type photoreceptor, in other words, a pyrazoline compound represented by general formula (1) is used as a charge transport material for the charge transport layer of a photoreceptor that is functionally separated into two layers: a charge generation layer and a charge transport layer. When used, the sensitivity of the photoreceptor is particularly improved and the residual potential is low. Further, in this case, a decrease in sensitivity and an increase in residual potential during repeated use can be suppressed to a practically negligible level. Therefore, the 4) type of photoreceptor will be described in detail.

As for the layer structure, a conductive layer, a charge generation layer, and a charge transport layer are essential, and the charge generation layer may be either an upper part of the charge transport layer or a lower part of the charge transport layer, but in an electrophotographic photoreceptor of the type that is used repeatedly. It is preferable to laminate a conductive layer, a charge generation layer, and a charge transport layer in this order mainly from the viewpoint of physical strength and, in some cases, from the viewpoint of chargeability.

The charge transport layer according to the present invention is formed by applying a solution in which a charge transport compound consisting of a pyrazoline compound represented by the above-mentioned general formula (1) and a binder are dissolved in an appropriate solvent and drying the solution. is preferred. As the binder used here, for example, acrylic resin (methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate, polysulfone, polyurethane, or repeating 9 units of these resins) Examples include copolymer resins containing two or more of these, with polyester resins and polycarbonates being particularly preferred.Also, photoconductive resins that themselves have charge transport ability, such as poly-N-vinylcarbazole, are preferred. Polymers can also be used as binders.

The blending ratio of the binder and the charge transport compound is 1
It is preferable that the charge transport compound is contained in an amount of 10 to 500 parts by weight per 00 parts by weight. The thickness of this charge transport layer is 2 to 1
00S silicon, preferably 5-30 microns, especially 8-30 microns
20 microns is suitable.

The charge transport layer of the present invention can contain various additives. Such additives include diphenyl, diphenyl chloride, 0-terphenyl, P-terphenyl, dibutyl phthalate.

Examples include dimethyl glycol phthalate, dioctyl tucrate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilaurylthiopropionate, 3,5-dinitrosalicylic acid, and various fluorocarbons.

Further, the solvent used in forming the charge transport layer of the present invention includes many useful organic solvents, such as benzene, naphthalene, toluene, xylene, mesitylene, chlorobenzene, etc. Aromatic hydrocarbons, aceto/ketones such as 2-butanone, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and ethylene chloride, dihydrofuran,
Examples include cyclic or linear ethers such as ethyl ether, and mixed solvents thereof.

The charge generating material used in the present invention can be a material that absorbs light and generates charge carriers with high efficiency. Preferred materials include selenium tellurium, selenium arsenic cadmium sulfide, amorphous silicon, etc. Inorganic substances, biryllium dyes, thiovirilicum dyes, triarylmethane dyes, thiazine dyes, cyanine dyes, phthalocyanine pigments, perylene pigments, indigo pigments, thioindigo pigments, quinacridone pigments, squaric acid pigments, Examples include organic substances such as azo pigments and polycyclic quinone pigments.

The thickness of the charge generation layer is 5μ or less, preferably 0-OS to 3μ.
is desirable.

The charge generation layer is provided by means such as vacuum evaporation, sputtering, glow emission IE or coating depending on the type of charge generation material used.

When coating, the charge-generating material may be provided as a binder, a resin dispersion, or a uniform solution of the binder and the charge-generating material.

When the charge generation layer is formed by coating a resin dispersion or solution of the charge generation material, the ratio of the binder in the charge generation layer is preferably 8071 or less, and preferably 40% Fi or less, since sensitivity will be affected if too much binder acid is used. desirable.

Examples of the binder used in the charge generation layer include polyvinylbutylene 2-rupolymethyl methacrylate, polyester,
Polyvinylidene chloride, chlorinated rubber, polyvinyltoluene,
A styrene-anhydrous butadiene copolymer or the like can be used.

Representative examples of the charge generating material that can be used in the present invention are listed below.

Charge generating substance (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (5) C-00-C C-00=C 11 C2H5C2H3 (51) 1 C2)15c2H5 02H5CHa (53) C2H5C2 possible ((b) ■ (CH,,)3°CHs (
CH,), OC1(.

Methyl squarate dye - Indigo dye (C!, 1./1678000) -
Thioindigo dye (C,1,/l678800) (6
1) β-type copper phthalocyanine (62) (63) ω0 (to)) (66) ωD These pigments may be used alone or in combination of two or more types, but β-type is particularly suitable. 1. The electrophotographic photoreceptor of the present invention has a photosensitive layer having a structure in which a charge-generating layer containing the pigment described above is coated on a suitable support, and a charge-transporting layer is laminated on the charge-generating layer. It can be created by using In this type of electrophotographic photoreceptor, an intermediate layer may be provided on a suitable support, a charge generation layer containing the aforementioned pigment may be formed thereon, and a charge transport layer may be formed thereon. This intermediate layer prevents the injection of zero free charge from the conductive support to the photosensitive layer when the photosensitive layer having the multilayer I-structure is charged, and also holds the photosensitive layer integrally adhered to the conductive support. It acts as an adhesive layer. This intermediate layer is made of metal oxide such as aluminum oxide, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, phenolic resin,
Epoxy resin, polyester resin, alkyd resin, polycarbonate, polyurethane, polyamide resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer,
Casein, gelatin, polyvinyl alcohol, nitrocellulose, water-soluble ethylene-acrylic acid copolymer, and the like can be used. The thickness of this intermediate layer or adhesive layer is suitably 0.1 to 5 microns, preferably 0.5 to 3 microns.

It is also possible to form a laminated structure in which the charge generation layer is provided on the charge transport layer. In this case, a known method such as a suitable terminating method can be used, and the pigment particles are preferably 5 μm or less, preferably 2 μm.
μ or less Optimally, it is desirable to set it to 0.5'μ or less.

The pigment can also be applied by dissolving it in an amine solvent such as ethylenediamine. Conventional methods such as blade, i-ear per, spray dipping, etc. are used for application.

Further, if necessary, the surface of the charge generation layer can be polished to a mirror finish in order to uniformly inject carriers into the charge transport layer above the charge generation layer.

The pyrazoline compound used in the present invention has hole transport properties, and when using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, the charge transport surface is negatively charged. In the exposed area, holes generated in the charge generation layer are injected into the charge transport material and then reach the surface to neutralize the negative charge, causing the surface potential to attenuate and leaving the unexposed area unexposed. There is a quiet and electric contrast between the two.

Various conventional visualization methods can be used for visualization.

As another specific example of the electrophotographic photosensitive φ east of the present invention,
For example, the above-mentioned hydrazone compound is used as a charge transport material, and the above-mentioned hydrazone compound is used in a charge transport medium consisting of a chronic binder (the binder itself may be a charge transport material such as poly-N-vinylcarbazole). It may also be a book in which a photosensitive li+ made of dispersed pigment is formed on a conductive layer. As the insulating binder and charge transport material used in this case, for example, Japanese Patent Publication No. 52-166
No. 7, JP-A-47-30328, JP-A No. 47-18545
The support used in the electrophotographic photoreceptor of the present invention disclosed in the specification may be any type of conductive layer conventionally used as long as it is imparted with conductivity.
) or t10 Specifically, aluminum, panadicum, molybdenum, chromium, cadmium, titanium, nickel, copper, zinc, palladium, indium, tin, platinum, gold,
Examples include metal sheets such as stainless steel and brass, and plastilag sheets on which metals are vapor-deposited or charged.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers, CRT printers, and electrophotographic plate making systems.

According to the present invention, the sensitivity is significantly higher than that of a good electrophotographic photoreceptor using a conventional organic photoconductive material, and the bright area potential remains constant even after repeated charging and exposure 10,000 times or more. The present invention will be explained according to examples under increased wind.

Example 1 Ammonia aqueous solution of casein (casein 1
1.2g, 28% ammonia water 1gs water 222m/)
Apply it with a Mayer bar and let it dry.

1 value 1. A contact layer of Og/m'' was formed.

Next, 5 g of bisazo pigment having the following structure and 2 g of butyral resin (degree of butyralization: 63 mol) were mixed with 9 mol of ethanol.
After being dispersed with a liquid dissolved in a solution of 5 m/m, it was coated on the adhesive layer to form a charge generation layer with a coating weight of 0.2 g/m'' after drying.

Next, the pyrazoline compound! (1) to 5gζpoly-4,
5 g of 4-dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight 30001) was dissolved in dichloromethane 7
The solution containing 150-π was applied onto the charge generating J- and dried, resulting in a coating amount of 101. A charge transport layer of Z'-- was formed.

The electrophotographic photoreceptor thus prepared was statically charged with 3' Sena at 05 KV using a Seiden Copying Paper Tester Mode/5P-428 manufactured by I-Denki and held in a dark place for 10 seconds. After exposure to light at 5/ux, the charging characteristics could be observed. .

The initial potential V ((V), the potential retention rate for 10 seconds in the dark is Rv (l, the half-decay exposure amount is E 1/2 (/ux * 5ec
) This shows the charging characteristics of this photoreceptor.

vO: 0580v RV: 91 Section BX/2: 6.31ux @ sec Examples 2 to 17 The following pigments were vacuum deposited on an aluminum plate with a thickness of 100 μm, and the charge generation layer with a thickness of 0×15 μm was immersed in an acid.

Next, polyester resin (Bi I”200: Toyobo ■
)5g and the pyrazoline compounds (2) to (14) exemplified in Section 1.
), (18), and (22λ@) dissolved in 150 m/150 m of dichloromethane to generate a charge! - It was coated on top and dried to form a charge transport tfd with a coating weight of I1 g/ln''.

The charging characteristics of the electrophotographic photoreceptor thus prepared were examined in the same manner as in Example 1, and the results are shown in Table 1.

Table 1 Selenium/tellurium on Alti (tellurium weight 10L: fb
) A charge generation layer having a thickness of 0.8 μm was formed by TLC dry deposition.

Next, the charge transport layer and the first layer used in Example 1 were cured and dried to give a coating weight of 1 ig/m''.

A photosensitive plate prepared from this camphor tree was subjected to charging characteristics in the same manner as in Example 1, and the results are shown below.

vo; 0600v 3v: 884 gt/2: 4.91ux@sec Example 19 5 g of the pyrazoli/based compound (1) used in Example 1 and Bo 13
g dissolved in dichloromethane 150snf VC
Type steel phthalocyania 1. After dispersing Og and dispersing it, it was applied on the casein layer 1 of the casein layer 1 (used in Example 1), and the coating amount after drying was determined as IQg.
/rn”.

The electrostatic charge of the photoreceptor thus prepared was measured using the same material as Example 1), and the results are shown below.

However, the imperial JC polarity was set to ■.

vo: ■560v ILv: 88 section 181/2: 11.3 /uX@sec real 1iI
Example A 20 A molybdenum plate (substrate) of 0.21Lm) with a cleaned thorn surface was fixed at a predetermined position in a glow emitting device q. Next, the inside of the tank is evacuated to approximately 5 x 1 (f' torr
The vacuum level was set to . -The input voltage of the IJO light heater was increased to stabilize the molybdenum base temperature at 150°C.

After that, hydrogen gas and silane gas (15St for hydrogen gas)
4) is introduced into the tank, and the amount of gas θ is set to 5 to the evaporation tank-conduction coil.
MHz high-frequency power was applied to generate a glow discharge inside the coil in the tank, resulting in a 30W power cutter. An amorphous silicon film was grown on the substrate under the above conditions and the same conditions were maintained until the film thickness reached 2 μm, after which glow discharge was stopped. After that, turn off the heating heater and high frequency power supply, and then
After waiting for the temperature to reach 100 degrees Celsius, the hydrogen gas and silica/gas outflow pulp were closed, and after the inside of the tank was once lowered to below 10'torr, the pressure was returned to atmospheric pressure and the substrate was taken out. A charge transport layer was formed in exactly the same manner as in Example 1.

The resulting good and bad light bodies were placed on a charging exposure experiment mount and the result was 0.
It was corona charged at 6 KV and immediately irradiated with a light image. One light image was irradiated through a transmission type test chart using a tungsten 4R ten lamp light source.

Thereafter, a good toner image was obtained on the surface of the photoreceptor by immediately cascading an e-chargeable developer (containing toner and carrier) onto the surface of the photoreceptor.

Patent applicant: Canon Co., Ltd. Copia Co., Ltd.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a layer containing at least one pyrazoline compound represented by the following general formula (1). General formula (1) (wherein R1 and R2 represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group. R1s R4, R and R
@ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group; - and tome can form a cyclic amino group;・can form a cyclic amino group. R,, R,, . . . and ELl. each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. )