JPS63151955A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body superior in photosensitivity and durability by incorporating a specified hydrazone compound in a photoconductive layer formed on an electric conductive substrate. CONSTITUTION:The electrophotographic sensitive body has a photosensitive layer containing at least one of the hydrazone compounds represented by formula I in which each of R1 and R2 is alkyl, alkoxy, or halogen; each of R3 and R4 alkyl, aryl, aralkyl, or a heterocyclic group; m is 0, 1, or 2; and n is 1 or 2. Since the hydrazone compound itself has no film forming capability, a binder resin is used to form a photosensitive layer. As for the charge generating material, except for polymer resins, such as polyvinylcarbazole, since it has no film forming capability, a binder may be used when needed, thus permitting the obtained electrophotographic sensitive body to be superior in sensitivity, durability and resistance to environmental conditions.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, a photoconductive layer formed on a conductive support has a ,
By containing a novel hydrazone compound, an electrophotographic photoreceptor having excellent photosensitivity and durability is provided.

(Prior Art) Electrophotography, as already disclosed by Carlson in U.S. Pat. After uniformly charging the surface of a conductive photoreceptor by corona discharge in a dark place, the light image is converted into an electrostatic latent image using photoconductivity, and this is colored with charged powder (toner). It is one of the image forming methods that attaches a substance and converts it into a visible image.

The basic electrical and photoelectric properties required of a photoreceptor in such electrophotography are that it can be charged to an appropriate potential in a dark place, that this potential can be maintained for an appropriate amount of time, and that it can be charged quickly by light irradiation. For example, the electric charge can be dissipated.

In such photoreceptors, amorphous selenium,
Inorganic photoconductive materials such as cadmium sulfide and zinc oxide have been widely used. Although these inorganic materials satisfy the above conditions, they also have some drawbacks. For example, cadmium sulfide and zinc oxide are used as photoreceptors by being dispersed in resin as a binder, but they have mechanical drawbacks such as smoothness, flexibility, hardness, tensile strength, and abrasion resistance, so they are used as is. cannot withstand repeated use. Furthermore, when using cadmium sulfide, consideration must also be given to hygiene issues.

In addition, amorphous selenium must be manufactured by vapor deposition, which not only increases manufacturing costs but also has no flexibility and is difficult to process into a belt shape.
It has drawbacks such as the toxicity of selenium and its sensitivity to heat and mechanical shock, so care must be taken when handling it.

In recent years, in order to eliminate the drawbacks of these inorganic photoreceptors,
Research on organic photoreceptors is progressing, and organic photoreceptors.

Two kinds of organic photoreceptors have been proposed, and some are in practical use because they have many advantages such as ease of film formation, ease of manufacture, light weight, flexibility, and variable 1-spectral sensitivity.

For example, 9 poly-N-vinylcarbazole and 2.4°7-
Photoreceptor consisting of dolinitrofluoren-9-one (US Pat. No. 3,484,237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 48-25658), Photoreceptor whose main component is a eutectic complex consisting of a dye and a resin
Publication No.) etc.

Furthermore, an electrophotographic photoreceptor has been proposed that combines a substance it' that generates electric charge with light (referred to as a charge-generating substance) and a substance that can transport the generated electric charge (referred to as a charge-transporting substance). ing. For example, U.S. Patent No. 3.79
No. 1,826 discloses a photoreceptor in which a charge transport layer is provided on a charge generation layer, and U.S. Pat. No. 3,764,315 discloses a photoreceptor in which a charge generation material is dispersed in a charge transport material. A photoreceptor having a photosensitive layer is described. By assigning the functions of this type of charge generation and charge transport to different substances, that is, by combining the charge generation material and the charge transport material, the characteristics can be improved.
Useful photoreceptors are provided.

Until now, many charge generating substances useful in this type of photoreceptor have been known. On the other hand, although various materials have been proposed as charge transport materials, it is currently difficult to say that they are necessarily satisfactory. The basic characteristics of an excellent charge transport material are that when it is charged, it can hold a sufficient potential, and that it can sufficiently transmit light of an effective wavelength that allows the charge to be generated from the charge-generating material. Furthermore, it has the ability to quickly transport the charges generated by the charge generating substance. Also,
Practical requirements include the ability to form a uniform film either alone or dissolved in a binder, and to be able to withstand harsh environmental conditions such as temperature, humidity, and ozone and NOx generated during corona discharge. It is necessary that the electrostatic properties do not deteriorate or change.

So far, as this type of charge transport material, polyphenyl compounds such as triphenyl have been classified by chemical structural formula, U.S. Patent No. 3.717.462, U.S. Patent No. 4.1
50,987, hydrazone compounds described in JP-A-55-52064, U.S. Patent No. 3.820
Diarylalkane compounds described in US Pat. No. 3,189,477, 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadi Azole, U.S. Patent No. 3゜8
Pyrazoline compounds described in No. 37.851 are relatively excellent charge transport materials that have been proposed in recent years. However, the current situation is that these charge transport materials do not satisfy all of the above conditions.

(Problems to be Solved by the Invention) The present invention provides an electrophotographic photoreceptor having excellent sensitivity, repeatability, durability, and the like.

[Structure of the invention]

(Means for Solving the Problem) As a result of intensive research, the present inventors discovered that a hydrazone compound with a specific structure is a truly useful charge transport material for electrophotographic photoreceptors, and further discovered that The present invention was completed by discovering that an electrophotographic photoreceptor using a charge transporting material has excellent properties.

That is, the present invention provides an electrophotographic photoreceptor having excellent properties using a hydrazone derivative with a novel structure.

An object of the present invention is to provide an electrophotographic photoreceptor that contains a novel charge transporting substance, has a low residual potential at high degrees of anger, and has high charge transport efficiency, so that the copying speed is high. Another object of the present invention is to reduce fatigue deterioration due to repeated use when used as a photoreceptor for electrophotography in which charging exposure, development, and transfer steps are repeated, and furthermore, to reduce the fatigue and deterioration caused by repeated use, and to maintain low humidity and high temperatures rather than low temperatures. Under various harsh environments with higher humidity.

An object of the present invention is to provide an electrophotographic photoreceptor that maintains stable characteristics and has excellent durability and environmental friendliness.

This object of the present invention is achieved by containing at least one compound represented by the following general formula (1) as a charge transport substance.

General formula (1) This object of the present invention is achieved by an electrophotographic photoreceptor characterized by having a photosensitive layer containing at least one azo compound represented by the following general formula CI) as a carrier generating substance. .

(In the formula, I R1 and R represent an alkyl group, an alkoxy group, or a halogen atom, and R3 and R4 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group. Also, 9m represents an integer of 0 to 2. and n represents 1 or 2.) To further explain the substituents, among R3, R2, R3 and R4, the alkyl group is 2, for example, a methyl group.

Indicates substituents such as ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and stearyl. Of R1 and R2, the alkoxy group represents a substituent such as a methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, or benzyloxy group, and the halogen atom represents a substituent such as a chlorine atom or a bromine atom. Represents a substituent. Of R1 and R4, the aral group refers to a substituent such as a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, or a fluorenyl group, and the aralkyl group refers to a benzyl group, a phenethyl group, a cinnamyl group, a benzhydryl group, Trityl group.

Indicates a substituent such as naphthylmethyl group? j! A ring group refers to a substituent such as a pyridyl group, a benzothiazolyl group, or a phthalazinyl group. Furthermore, the alkyl group, aryl group, aralkyl group, and heterocyclic group of R1 and R4 may have a substituent such as the alkyl group, alkoxy group, or halogen atom shown in the above specific examples of R1 and R1.

The compound of the present invention represented by the general formula (T) is 9
For example, it can be manufactured by the following method.

One method is to react hydrazine represented by the following general formula (II) or its mineral acid salt with an aldehyde represented by the general formula (III) in an organic solvent.

General formula CDI) (wherein R,, R2, m and n are the same as in general formula (1)) As the solvent, a wide range of non-reactive organic solvents can be used, but alcohols such as methanol and ethanol are preferable. etc., dimethylformamide, dioxane, etc. can be used alone or in combination.

In another method, hydrazine represented by the following general formula (IV) or its mineral acid salt is reacted with an aldehyde compound represented by the above general formula (V) in a solvent.

General formula (VT) H! N-NH-R3 (in the formula +R3 is the same as in general formula (1)) Then in a compound represented by the following general formula (V) and a solvent,
Preferably by reacting under basic conditions.

The hydrazone compound of the present invention can be obtained.

General formula (V) R, -X (wherein, X represents a negative group such as a halogen atom, and R4
(same as general formula (1)) As the solvent, a wide range of non-reactive solvents can be used, but preferably protic solvents such as water and alcohols, or aprotic polar solvents such as dimethyl sulfoxide and dimethyl formamide. , acetone, ketones such as methyl ethyl ketone, benzene, toluene.

Aromatic hydrocarbons such as xylene, tetrahydrofuran.

Ethers such as dioxane, dichloromethane, l, 2-
Chlorinated hydrocarbons such as dichloroethane or pyridine,
Amines such as triethylamine can be used alone or in combination.

Next, representative examples of the hydrazone compound of the present invention are listed below.

[Hydrazone compound]

2H5 These compounds can be used alone or in combination of two or more.

The photoreceptor of the present invention contains the above-mentioned hydrazone compounds, and photoreceptors with various characteristics can be obtained depending on how these hydrazone compounds are applied. For example, a hydrazone compound as a charge transporting substance is provided on a conductive support substrate in the same layer as a charge generating substance, or a configuration called a single layer type photoreceptor, or a first layer mainly containing a charge generating substance. It can be used in a structure commonly called a laminated type photoreceptor, which is formed by laminating two second layers mainly containing a charge transporting substance on a conductive supporting substrate. These configurations are appropriately selected depending on the polarity of the photoreceptor used. In addition, three charge generating substances are used in the present invention.

For example: Selenium as an inorganic compound.

Inorganic optical semiconductors such as selenium alloys, CdS, ZnO, CdSe, and amorphous silicon can also be used.

Preferably, an organic charge generating substance is used.

Examples of organic charge-generating substances include phthalocyanine compounds such as τ-type metal-free phthalocyanine, ε-type copper phthalocyanine, Aluminum V-luftacyanine, vanadyl phthalocyanine, titanyl phthalocyanine, and indium chlorophthalocyanine, and disazo compounds.

Indigo compounds such as thioindigo, indanthrene thread quinone compounds such as dibromuanthanthrone.

Examples include perylene compounds and perinone compounds.

Since the hydrazone compound in the present invention does not have film-forming ability by itself, a binder resin is used to form it as a photosensitive layer. Further, since charge generating substances cannot form a film by themselves except for polymeric resins such as polyvinylcarbazole, a binder may be used as necessary.

In the present invention, the binder preferably used is a highly electrically insulating film-forming polymer or copolymer. Among such polymers and copolymers, binders preferably used in the present invention include phenol resins, polyester resins, vinyl acetate resins, polycarbonate resins, polypeptide resins, cellulose resins,
Polyurethane resin, polyvinylpyrrolidone, polyethylene oxide, polyvinyl chloride resin.

Starch, polyvinyl alcohol, acrylic copolymer resin, methacrylic copolymer resin, silicone resin.

Polyacrylonitrile copolymer resin, polyacrylamide, polyvinyl butyral, polyvinyl carbazole,
Examples include polyvinylidene chloride resin. These polymer binders may be used alone or in combination of two or more, but the binders that can be used in the present invention are not limited to these. Further, in the photoreceptor of the present invention, a charge generation layer containing a charge generation substance as a main component is provided on the conductive support via an intermediate layer if necessary, and adjacent to the charge generation layer the charge generation layer containing a charge transport substance as a main component is provided. A stacked structure including a charge transport material may also be used. In addition, in the case of such a laminated structure, the dispersion obtained by ■ coating or ■ micronizing the charge-generating substance in a dispersion solvent using a ball mill, attritor, etc., and mixing and dispersing it with a polymer binder as necessary. It can be provided by a method such as applying a liquid. The polymer binder used at this time may be the same as that used in the charge transport layer.

Alternatively, it may be a single photosensitive layer comprising the hydrazone compound according to the present invention and a binder.

In addition, the hydrazone compound according to the present invention has a binder of 10
Preferably, 10 to 300 parts by weight of the charge transport material per 0 parts by weight. However, the present invention is not limited only to this range. The thickness of this photosensitive layer is determined by the required photosensitivity and durability, as well as the mixing ratio of the charge generating substance and the charge transporting substance to the binder. The thickness of the photosensitive layer on the supporting conductive substrate is preferably 50 microns or less, preferably about 7 to 30 microns, from the viewpoint of film flexibility.

The photosensitive layer can also be coated with a layer that serves as a protective layer, if necessary.

The support used in the electrophotographic photoreceptor of the present invention includes:

Any material may be used as long as it is imparted with electrical conductivity, and any type of electrically conductive layer conventionally used may be used. Specifically, metals such as aluminum, copper, stainless steel, and brass, plastics or conductive particles 9 on which aluminum, indium oxide, tin oxide, etc. are vapor-deposited or laminated, for example carbon black.

Examples include plastics in which tin particles and aluminum particles are dispersed. Also, regarding its shape.

It may be sheet-shaped, cylinder-shaped, or other shapes. Note that when using the electrophotographic photoreceptor according to the present invention, the light source is usually a halogen lamp, etc.
When the charge generating substance is phthalocyanine.

Because the sensitivity is more than 750 parts m, gallium-aluminum-arsenic semiconductor laser ° (oscillation wavelength 780 nm)
) can also be used.

Next, the present invention will be explained in more detail with reference to synthesis examples and examples, but the present invention is not limited to the following examples. In the following examples, "parts" refer to parts by weight.

Synthesis Example 1 l-(4-methylphenyl)-1,2,3,4-tetrahydroquinoline-6-carboxaldehyde-1'
-Synthesis of diphenylhydrazine (exemplified compound (1)) 1-(4'-methylphenyl)-1,2,3,4-tetrahydroquinoline-6-carboxaldehyde 3°8
and 1.9 parts of sodium acetate were added to 40 parts of ethanol.

Further 1,1. - 368 parts of diphenylhydrazine hydrochloride was added and heated under reflux for 2 hours.

After cooling, the precipitated crystals were filtered and washed with ethanol.
The crude product obtained by drying was recrystallized using a mixed solvent of acetonitrile and toluene to obtain 4.9 parts of purified product (yield 78
．． 1%) was obtained as a pale yellow crystalline powder.

Elemental analysis value: Czq H27N, calculated value as s (%
): C, 83, 42, H, 6° 52; N.

10,06 Actual value (%): C, 83,30; H, 6,61; N.

10, 15 Infrared absorption spectrum: r(-CH=N-11518
a+1-' Synthesis Example 2 l-(4-chloro-2-methylphenyl)-1,2゜3
．． Synthesis of 4-tetrahydroquinoline-6-carpoxyaldehyde 1-ethyl-1'-(1-naphthyl)-hydrazone (exemplified compound (7)) 1-(4'-chloro-2-methylphenyl)-1 , 2゜ 5.7 parts of 3.4-tetrahydroquinoline-6-carboxaldehyde and 3.7 parts of 1'-ethyl-1'-(1-naphthyl)hydrazine were added to 50 parts of ethanol, and then 0.5 parts of acetic acid was added. 1 part was added and heated under reflux for 2 hours.

After cooling, the precipitated crystals were filtered and washed with ethanol.
The crude product obtained by drying was recrystallized using acetonitrile to obtain 6.8 parts of purified product (yield 74.9%) as pale yellow needle-like crystals.

Elemental analysis value: Calculated value (%) as C, tqHzllN3Cl: C, 76,72; H, 6,22; N.

9.26; C1,7,80 Actual value (%): C, 76,55, H, 6,37; N
.

9.41; C1,7,62 Infrared absorption spectrum: r(-CH=N-) 1
525cm-' Synthesis Example 3 l-(4'-n-butylphenyl) -1,2,3,4
-Tetrahydroquinoline-6-carpoxyaldehyde 1,1-diphenylhydrazone (exemplary compound (9))
Synthesis of 1-(4'-n-butylphenyl)-1,2,3,4-
Tetrahydroquinoline-6-carboxaldehyde 4
．． 4 parts and 1.9 parts of sodium acetate were added to 50 parts of ethanol, and further 3.8 parts of 1,1-diphenylhydrazine hydrochloride were added and the mixture was heated under reflux for 2 hours.

After cooling, the precipitated crystals were filtered and washed with ethanol.
The crude product obtained by drying was recrystallized using a mixed solvent of acetonitrile and toluene to obtain 5.7 parts of purified product (yield: 82.
2%) was obtained as a pale yellow crystalline powder.

Elemental analysis value: as C2□HssNs Calculated value (%): C, 77,82; H, 9,80; N.

12, 38 Actual value (%): C,? 7.65, H, 9,66, N.

12,51 Infrared absorption spectrum: r(-CH=N-) 1
535cm-'Example 1 Dibrome anthanthrone 0 o, 4 parts Polyester resin (Vylon 200) 0.5
Part 1.2-dichloroethane 9.5
The photoconductive composition was dispersed in a vibrating mill for 2 hours, and the resulting photoconductive composition was coated on an 80μ aluminum plate with a wire bar to a dry film thickness of 0.5μ.
A charge generation layer is formed by drying for 1 hour in an oven uniformly heated to 00°C. Next, a solution having the following composition was prepared so that it was coated on the charge generation layer to a thickness of 15 μm.

Compound (1) 0.3
Polyester resin (Vylon 200) 0.
4 parts dichloroethane 2.
It was coated with a 6 part T wire bar and dried for 30 minutes in an oven uniformly heated to 80° C. to produce a laminated photoreceptor.

-5, OKV for the sample thus obtained.

Corona discharge was applied with a corona gap of 10 mm and a charging speed of 10 m/lll1n, and after 10 seconds after the discharge was stopped, a tungsten light source of 2854 was used. OLux
Exposure at an illuminance of The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was defined as the sensitivity. The sample measured in this manner had a maximum surface charge of -620V, a dark decay rate of 5.0%, a sensitivity of 2.4 Lux, sec, and a residual potential of -30V.

Example 2 Disazo compound 0.4 part Acrylic resin (Dianal) (R113) 0.
2 parts vinyl chloride-vinyl acetate resin (VMCH) 0
．． 2 parts ethyl acetate 14
The photoconductive composition was dispersed in a vibrating mill for 2 hours, and the resulting photoconductive composition was coated with a 5μ thick aluminum foil and a 75μ thick aluminum foil.
A charge generation layer was formed on the laminate film with the polyester film using a wire bar so that the dry film thickness was 0.5 μm, and left in an open oven uniformly heated to 130° C. for 1 hour. Next, in Example 1, a laminated photoreceptor was prepared and tested in the same manner as in Example 1, using compound (4) instead of compound (1).

Maximum surface charge amount -680V, dark decay rate 7.2%, sensitivity 2
°I Lux-sec + residual potential -19V.

Example 3 40 parts of copper phthalocyanine and 0.5 part of tetranitrocopper phthalocyanine are dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring. - Pour the dissolved solution into 5,000 parts of water to precipitate a composition of F4 phthalocyanine and tetranitrocopper phthalocyanine, then filter, strain with water, and dry at 120° C. under pressure.

The above copper phthalocyanine composition 1.0 parts Compound (9) 2.5 parts Acrylic polyol (Takelac A-702) 3.6 parts Epoxy resin (Epon 1007) 0.5 parts Methyl ethyl ketone 5.2 parts Cellosolve acetate 1.3 parts The above composition is milled in a magnetic ball mill for 48 hours to obtain a photoconductive composition.

Next, this photoconductive composition was roll coated onto the aluminum of a laminate film of a 5 micron thick aluminum foil and a 75 micron polyester film to a dry film thickness of 8 microns, and was uniformly heated to 110°C. The sample was placed in a heated oven for 1 hour to prepare an electrophotographic photoreceptor. Corona discharge was applied to the obtained sample at +5.7 KV, a corona gap of 10 mm, and a charging speed of 10 m/sin, and 10 seconds after the discharge stopped, 2
Exposure is performed using an 854 tungsten light source with an illuminance of 10 Lux. The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was defined as the sensitivity. The sample measured in this way had a maximum surface charge of 600 V and a dark decay rate of 10%.
, sensitivity 2.7 Lux sec *Residual potential 25V, both chargeability and sensitivity are of sufficient value for practical use, no induction is observed in 1 surface potential decay upon charging exposure, and a light decay curve of 3 curves is observed. Ta. In addition, 10,000 copies were made continuously using this photoconductor with positive charging using a copying machine, but the resulting images had excellent gradation, and even when copies were made using an ordinary photograph as an original, Beautiful images can be obtained in terms of detailed intermediate color density, and there is no change in sensitivity.
Furthermore, there are scratches on the photoreceptor.

A clear image with no scratches was obtained in the copied image.

Examples 4 to 12 In Example 1, τ was used instead of dibromancethrone.
Type metal-free phthalocyanine, polycarbonate resin instead of polyester resin (Panlite L-1250
), laminated photoreceptors were prepared in the same manner as in Example 1 using various hydrazone compounds shown in Table 1 instead of Compound 1, and the samples thus obtained were measured in the same manner as in Example 1. , maximum surface charge, dark decay rate, sensitivity, and residual potential were as shown in the following table.

Table ■ [Effects of the invention] The present invention has the above structure, and when using it,
High sensitivity even for positive and negative charges.

In addition, there is little deterioration of the photoreceptor due to repeated use, and in practical soil, it has excellent charge retention ability, environmental friendliness with respect to sensitivity changes, and durability under conditions ranging from low to high temperatures and from low humidity to high humidity. .

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized by having a photosensitive layer containing at least one compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 and R_2 represent an alkyl group, an alkoxy group, or a halogen atom, and R_3 and R_4
represents an alkyl group, an aryl group, an aralkyl group or a heterocyclic group. Also, m represents an integer from 0 to 2, and n is 1
Or represents 2. )