JPS5872150A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic photoreceptor of high sensitivity and excellent durability by holding a layer contg. a specific pyrazoline compd. more particularly in a charge transfer layer. CONSTITUTION:The photoconductive layer contg. the compd. expressed by the formula[R1, R2 are H, alkyl, (substd.) aralkyl, (substd.) aryl, the former two substituents 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, and R7-R12 are H, halogen alkyl, akoxy]. More particularly, a charge generating layer and a charge transfer layer are contained in this order in the charge transfer layer provided on a conductive substrate. Thus the photoreceptor having good filming characteristic, high sensitivity and excellent durability 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 consisting of a pyrazoline compound.

2. Description of the Related Art Hitherto, photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive material wires have many advantages, such as being able to be charged to an appropriate potential in the dark, and being able to quickly dissipate the charge by illuminating the line with light, which causes less charge dissipation in the dark. Although it has advantages, it also has various disadvantages. For example, in a selenium-based photoreceptor, crystallization easily progresses due to factors such as temperature, humidity, dust, and pressure, and if the ambient temperature exceeds 40°C at q#, crystallization will be significant, and chargeability will decrease or When white spots appear on me, there are nine defects. Furthermore, selenium-based photoreceptors and cadmium sulfide-based photoreceptors are stable and provide good sensitivity and durability when used over time under high humidity, but have the drawback of being susceptible to sagging.

9. Zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal, but these sensitizing dyes do not cause deterioration due to charging and photobleaching due to exposure light. The resulting rounding has the drawback of not being able to provide a stable rounding 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 lightness compared to the aforementioned inorganic photoconductive materials. However, the reason why it has been difficult to put it into practical use until now is that sufficient film forming properties have not been obtained, and inorganic-based This is because it is inferior to photoconductive materials. In addition, hydrazone compounds disclosed in U.S. Patent No. 4,150,987, etc., triarylpyrazoline compounds disclosed in U.S. Pat. No. 3,837,851, etc.
Low-molecular organic photoconductive materials such as 9-styrylanthracene compounds described in JP-A-1-94828 and JP-A-51-4829 have been proposed. By appropriately selecting the binder used, these low-molecular-weight organic photoconductive materials have become able to eliminate the film-forming defects 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 eliminate the above-mentioned drawbacks and disadvantages and provide a novel electrophotographic photoreceptor.

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

Another object of the present invention is to provide a compound suitable for a charge transport material used in a photosensitive device comprising a laminated structure of a charge generation layer and a charge transport layer.

This object of the present invention is achieved by an electrophotographic photoreceptor having a layer containing a pyrazoline compound represented by the following general formula (1).

In the formula, hR1 and R1 are a hydrogen atom, a methyl group, an alkyl group such as an ethyl group, a propyl group, a butyl group, or an amyl group (especially preferably an alkyl group having 1 to 4 carbon atoms), a benzyl group, or a phenethyl group. , represents an aralkyl group such as a naphthylmethyl group, or an aryl group such as a phenyl group or a naphthyl group. These aralkyl groups and aryl groups have hydroxyl groups, chlorine atoms, bromine atoms, etc.
- Atom, di-substituted amino groups such as cyan group, dimethylamino group, diethylamino group, di-substituted amino group, diphenylamino group, dibenzylamino group, methyl group, ethyl group, propyl group.

Alkyl groups such as butyl groups, methoxy groups, ethoxy groups,
It may be substituted with a flukoxy group such as a propoxy group or a butoxy group.

'l s R4s R* and B. are substituted or terminally substituted alkyl groups (e.g., methyl group, ethyl group, propyl group, butyl group, amyl group, octyl group, 2- and droxyethyl group, 3-hydroxypropyl group , 2-chloroethyl group, 2-cyanoethyl as 2-N,N-diethylaminoethyl group, 3-N,N-diethylaminopropyl group, 3-chloropropyl group, 4-hydroxybutyl group, 3-methoxyptetravir group, 3-ethoxyglobyl group, etc.), substituted or terminally substituted aralkyl groups (e.g.,
Benzyl group, 7enether group, α-su7tylmethyl group, β
-su7thylmethyl group, 4-methylbenzyl group, 4-methoxybenzyl group%2-chlorobenzyl group, 2.4.6
-Doriclo I2 Hensyl group, 3-hydroxybenzyl group, 3-cyanobenzyl it, 2,6-dichloro-4-
methylbenzyl group, 3-nitrobenzyl group) or substituted or unsubstituted aryl group (e.g. phenyl group, tolyl group, xylyl group, biphenyl group).

α-naphthyl group, β-7thyl group% 4-meth, diphenyl group, 4-ethoxyphenyl group, 2-ri o 7 x
, nyl group s 21jL6- )lichlorophenyl group, 2,6-dichloro-4-methylphenyl group.

3-cyanophenyl group, 4-hydroxyphenyl group, 3
-nitrophenyl group, 4-N,N-dimethylaminophenyl group, 4-N,N-diethylaminophenyl group, etc.). Furthermore, a cyclic amino group (eg, pyrrolidino group, piperidino group, morpholino group, etc.) can be formed by Rs and R4 and R3 and R.

几1, "ms" +1, R4゜, Ru jiP YohiR
at Fi, hydrogen atoms, halogen atoms (e.g., chlorine atom, bromine atom, etc.), alkyl groups (e.g., methyl group,
ethyl group, propyl group, butyl group, amyl group, octyl group, etc.) or an alkoxy group (eg, 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 Examples These compounds can be used in combination.

As the electrophotographic photoreceptor containing the pyrazoline compound represented by the general formula (1), any type of electrophotographic photoreceptor using an organic photoconductive substance can be applied, but preferable types include 1) Electron-donating type. A charge transfer complex formed by a combination of a substance and an electron-accepting substance.

2) An organic photoconductor sensitized by adding a dye.

3) Hole Ma) IJ Lux pigment dispersed.

4) Functionally separated charge generation layer and charge transport layer.

5) Those whose main components are a eutectic complex consisting of a dye and a resin and an organic photoconductor.

There are also charge transfer complexes in which an organic or inorganic charge generating material is added, among which types 3) to 6) are desirable.

Furthermore, when using a type 4) type photoreceptor, or when a pyrazoline compound represented by the general formula (1) is used as a charge transport material for the charge transport layer of the photoreceptor, the sensitivity of the photoreceptor is particularly improved and the sound is pleasant. The potential is also 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 above or below the 1JL 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-degradation layer in this order, mainly from the viewpoint of physical strength, and in some cases from the viewpoint of chargeability.

According to the present invention, cargo transport 1@ is performed by applying a solution in which a charge transporting 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. It is preferable to form it by. Examples of the binder used here include acrylic resin and methacrylic resin.

Vinyl chloride resin, vinyl acetate resin, phenolic resin 11, epoxy Kikawa f, polyester resin I, alkyd resin, polycarbonate, polysulfone.

Examples include polyurethane and copolymer resins containing two or more repeating units of these resins, with polyester resins and polycarbonates being particularly preferred. Additionally, photoconductive polymers having an inherent charge transport ability, such as poly-N-vinylcarbazole, can also be used as binders.

The blending ratio of the binder and the charge transport compound is 1
00 parts by weight of the charge-permeable compound lθ~500″3[1
The thickness of this charge transport layer, preferably in parts, is
2-100 microns, preferably 5-30 microns, especially 8-20 microns are suitable.

The *+'ir-transmission of the present invention can contain divine additives. Gagaru e5:i machining,
Diphenyl, m-diphenyl, o-turnenyl, P-
Terphenyl, dibutyl uthaletate.

Dimethyl glycol phthalate, dioctyl phthalate, triphenyl #string, methylnaphthalene, benzophenone, chlorinated paraffin, dilauryl thioglobionone)
, 3,5-dini, trosalicyl, and various fluorocarbons.

Furthermore, the common agents used to form the charge transport layer of the present invention include many common organic solvents. Typical examples include aromatic M-based hydrocarbons such as benzene, naphthalene, toluene, xylene, meziprene, and chlorobenzene; ketones such as acetone and 2-butano; Examples include logenated aliphatic hydrocarbons, broken or linear ethers such as tetrahydrofuran and ethyl ether, and mixtures thereof.

As the electron element @4.F used in the present invention, any old material can be used as long as it absorbs light and generates charge carriers with extremely high efficiency, and preferred materials include Inorganic materials such as selenium, tellurium, selenium/arsenic cadmium sulfide, amorphous silicon, etc.
and biryllium yarn dyes, thiopyrylium dyes, triarylmethane dyes, thiazine dyes, and cyanine dyes.

Phthalocyanine pigments, perylene pigments, indigo pigments, thioindigo thread pigments, quinacridone pigments, squaric acid pigments, azo pigments.

Organic substances such as multi-quinone pigments can be removed.

The thickness of the charge generation layer is preferably 5μ or less, with a thickness of 0.05 to 3μ.
is desirable.

The charge generating material is provided by means such as vacuum deposition, sputtering, glow discharge or coating.

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

When the charge generation layer is formed by applying a resin dispersion oil or bath liquid containing the charge generation material, the proportion of Ba Ingu in the charge generation layer is preferably 80 or less, since a large amount of binder used will affect the sensitivity. It is desirable that the diameter be less than 40 cm.

As the binder for use in 奄σding@seimasu, polyvinyl butyral, polymethyl methacrylate, polyester, polyvinylidene chloride, rubber chloride, polyvinyltoluene, styrene-anhydride man-butadiene military combination, etc. can be used.

Typical examples of charge-generating substances that can be used in the present invention are: (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (5) 11 C2+15
C2H5531 q) - C2 Teng (541 1 (CI (2) 30CH3 (CK) 30CH5 (to) squaric acid methine dye) Indigo dye (0,1,)), 178000) -
Thioindigo dye (C, 1,) 7678800) (61
) β-type copper phthalocyanine (62) (63) (64) (65) (66) (Excellent 7) These pigments are 111! 1 or 2ai or more can be used in combination. In addition, the crystal form of these pigments is
It may be α type, β type or any other type, but β type is particularly preferred.

The electrophotographic photoreceptor of the present invention uses a photosensitive layer having a structure in which a charge generation layer containing the pigment described above is coated on a suitable support, and a charge transport layer is laminated on the charge generation layer. It can be created by 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 free charges from the conductive support to the photosensitive layer during the -it time of the photosensitive layer having a laminated structure, and also allows the photosensitive layer to be integrally adhered and held to the conductive support. It acts as an adhesive layer. This intermediate layer can be made of metal oxides such as aluminum oxide or polyethylene, polyglobylene,
Acrylic resin, methacrylic resin, vinyl resin, phenol resin, epoxy resin, polyester resin, alkyl resin, polycarbonate, polyurethane, polyimide resin, vinylidene chloride resin, vinyl chloride-vinyl acetate copolymer, casein, gelatin, polyvinyl alcohol , nitrocellulose, aqueous ethylene-acrylic acid copolymer, and the like can be used. The thickness of this intermediate layer or adhesive layer is 0.1μ to 5μ, preferably 0.5 to 3μ.
is appropriate.

Alternatively, a laminated structure may be provided in which a multilayer layer is provided on a charge transport layer, and in this case, an appropriate surface retention layer may be formed.

For the dispersion of pigments, conventionally known methods such as ball mills and attritors can be used, and it is desirable that the pigment particles be 5 microns or less, preferably 2 microns or less, most preferably 0.5 microns or less.

The pigment can also be applied by dissolving it in an amine solvent such as ethylenediamine. Conventional methods such as plaid, Mayer bar, and spray dipping 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 surface of the charge transport layer must be negatively charged.・When exposed to light, holes generated in the charge transport layer in the exposed part are injected into the charge transport layer, and then reach the surface 7 and neutralize the negative charge, causing attenuation of the potential (Table If) and a gap between it and the uncod part. Electrostatic contrast occurs.

Various conventionally used developing methods can be used for visualization.

Another specific example of the electrophotographic photoreceptor of the present invention is
For example, the above-mentioned hydrazone compound is used as a charge-transporting substance, and the above-mentioned hydrazone compound is placed in a charge-transporting medium consisting of this and an insulating painter (which may also be a charge-transporting substance such as kaposi-N-vinylcarbazole). A photosensitive material made of dispersed pigment may be formed on a conductive layer. For example, the insulating binder and charge transport material used in this case are disclosed in Japanese Patent Publication No. 52-1667.
It is possible to use those disclosed in Japanese Patent Laid-Open No. 47-30328, Japanese Patent Application Laid-open No. 47-18545, and the like.

The support used in the electrophotographic photoreceptor of the present invention includes 41
11. Any type of conventionally used special conductive layer may be used as long as it is imparted with properties.

Specifically, aluminum, vanadium, molybdenum,
Chromium, cadmium, titanium, nickel, copper, zinc, palladium, indium, tin, platinum, gold, stainless steel,
Examples include a metal sheet such as brass or a plastic sheet on which metal is vapor-deposited or laminated.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It can also be widely used in electrophotographic application fields such as electrophotographic plate making systems.

According to the present invention, the sensitivity is significantly higher than that of electrophotographic photoreceptors using conventional organic photoconductive materials, and the bright area potential remains constant even after repeated charging and exposure more than 10,000 times. There is no increase in dark potential and no decrease in dark potential.

Hereinafter, the present invention will be explained according to examples.

Example 1 Ammonia aqueous solution of casein (casein 1
1.2F, 28% ammonia water If.

Water (222 sd) was applied and dried using a t-Meyer bar to form the entire adhesive layer with a coating amount of LOt/d.

Next, bisazo pigment 5F having the following structure and butyral resin (butyralization degree 63 mol%) 22 were mixed with ethanol 9
After being dispersed with a solution dissolved in 5d, the charge generating layer was coated on the adhesive layer to form a charge generating layer having a coating weight of 0.297 after drying.

Next, the pyrazoline compound (1) was added to 51. poly-4,4
'-Dioxydiphenyl-2,2-carbonate (viscosity average molecular weight 3000035 ft) A solution dissolved in dichloromethane 15011 was applied to the charge generating layer and dried to form a charge transport layer with a coating weight of 1027. Formed.

The electrophotographic photoreceptor thus prepared was statically charged with corona at θ5KV using Kawaguchi Denki's Seiki Copying Paper Tester ModetSP-428, held in a dark place for 10 seconds, and then exposed at an illuminance of 5 Lux. The charging characteristics were investigated.

The initial potential Vo (V), the potential retention rate for 10 seconds in the dark is RvO), and the half-attenuated Liyuan-tong is El/2 (tux・5e
c) Charging characteristics of this photoreceptor are shown.

■o: θ620■ Rv: 92chi El/2: 6.6 tux-sec actual travel examples 2-1
8 The following pigment was vacuum deposited on an aluminum plate with a thickness of 100 μm to form a charge generation layer with a thickness of 0.15 μm.

Next, polyester resin (Pine 200: Toyobo ■
) 5F and the above-mentioned pyrazoline compounds (2) to (13
), (15), (198 (21), (25), (27)
5fi respectively dissolved in dichloromethane 150- is applied and dried on charge generation 1-, and heavy industry ■ is 11 f/-
An electrical transport layer was formed.

The electrophotographic A-sensitizer prepared using this strain was used in conjunction with Example 1 to examine its charging characteristics, and the results are shown in Table 1.

Table 1 Example 19 Bicizoline compounds used in Example 1 (5t of υ and 1
7-N-vinylcarbazole (1.3 million molecules) 5f2i
β-type copper phthalocyanine 1.02 was added to a solution dissolved in dichloromethane 150-, and after dispersion, it was applied onto the casein layer of the aluminum plate provided with the casein l- used in Example 1,
The coating amount after drying was t-10t/1.

Charge measurement of the photoreceptor thus prepared was carried out in the same manner as in Example 1, and the results are shown below.

However, the charging polarity was set to ■.

■o: ■560V Rv: 90% El/2: 11. Otux-sec Example 20 Selenium e Tellurium (Tellurium Jiit10-) on aluminum plate
was vacuum evaporated to form a charge generating JvI with a thickness of 0.8 μm.

Next, the same charge transport layer as used in Example 1 was coated and dried to give a coating weight of 11 t/m''.

The electrophotographic photosensitive plates prepared in this manner were used in Example 1 and I''.
Mr. J and band 1 [examine the characteristics and reduce the results to the following] VO: 0570 ■ RV: 87 CH 11/2: 4.6 tux・sec Example 21 0, 2 whose surface was cleaned − Shore molybdenum board (substrate)
was fixed at a predetermined position in the glow discharge I〉 deposition tank. Next, the tank was completely evacuated to a vacuum level of 5 x 10-' torr. Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C. After that, hydrogen gas and silane gas (15 liters per hydrogen gas) are introduced into the tank to generate a gas current and steam Mfli+! Adjust the main valve to O65
stabilized at torr. Next, Fat Sen Coil V Ko5 M
A high frequency direct force of Hz was applied to generate glow emission inside the coil in the tank, resulting in 30W of human power. the above·
In rice cultivation, m = upper vC amorphous silicon ilK k was grown under the same conditions until the film thickness reached 2μ, and then glow discharge was discontinued. After that, turn off the heating heater, and wait for the substrate temperature to reach 1001::, close the hydrogen gas and silane gas outflow valves, and once reduce the inside of the tank to below 10-'t'orr. After that, the pressure was returned to atmospheric pressure and the substrate was taken out. Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1.

The photoreceptor thus obtained was placed in a charging exposure experiment apparatus KPj9.
F) Corona charging was performed at 6 KV and a light image was immediately irradiated. The light image was illuminated through a transmission type test chart using a tungsden lamp light source.

Thereafter, a good toner image 16 was obtained on the surface of the photoreceptor by immediately cascading a charged 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, milk and poultry represent a hydrogen atom, an alkyl group, a substituted or terminally substituted aralkyl group, or a substituted or terminally substituted aryl group. R1, R4s R1 and B are substituted or A terminally substituted alkyl group, a substituted or terminally substituted aralkyl group 0t's a, which indicates a circle-substituted or terminally substituted aryl group, and R4 form a cyclic a) group, which is a hydrogen atom, a halogen atom, or an alkyl group. group or alkoxy group. )