JPH04149446A - Electrophotographic photosensitive body - Google Patents

Abstract

PURPOSE:To obtain high sensitivity and durability by incorporating a hydrazone component which contains a specific enamine group into a photosensitive layer. CONSTITUTION:A photosensitive layer, which has an electrically conductive substrate containing a hydrazone compound containing an enamine group represented by a formula I, is formed. In the formula I, A and B represent hydrogen, an alkyl group that may contain a substituent group, an alkyl group that may contain a substituent group, or a heterocyclic group that may contain a substituent group. However, the case where both A and B are hydrogen or an alkyl group is excluded. A' represents an alkyl group that may contain a substituent group or a heterocyclic residue that may contain a substituent group, while R and R' represent an alkyl group, hydrogen, or an alkyl group that may contain a substituent group. However, the case where both R and R' are hydrogen is excluded. Thus, high sensitivity and high durability are attained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor containing an enamine group-containing hydrazone compound in a photosensitive layer formed on a conductive support. The present invention relates to an electrophotographic photoreceptor.

<Prior Art> Conventionally, in electrophotographic technology, inorganic substances such as selenium, cadmium sulfide, amorphous silicon, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors.
In recent years, much research has been conducted on the use of organic photoconductive materials as electrophotographic photoreceptors. Here, the basic properties required for an electrophotographic photoreceptor are (1) high chargeability due to corona discharge in the dark;

(2) The resulting corona charge has little attenuation in the dark.

(3) Charges are quickly dissipated by light irradiation.

(4) There is little residual charge after irradiation with light.

(5) Increase in residual potential and decrease in initial potential due to repeated use are small.

6) There is little change in electrophotographic characteristics due to temperature and humidity.

Conventional inorganic electrophotographic photoreceptors such as selenium and cadmium sulfide have basic properties that meet the requirements for photoreceptors, but there are manufacturing problems such as high toxicity and difficult film formation. , has disadvantages such as poor plasticity and high manufacturing cost. Looking further into the future,
Due to the depletion of resources, there is a limit to production, and also from the viewpoint of pollution due to toxicity, it is desired to use photoreceptors made of organic materials instead of inorganic materials. In view of these points, research on electrophotographic photoreceptors made of organic materials has been actively conducted in recent years, and as a result, electrophotographic photoreceptors using various organic materials have been proposed and put into practical use. There is also.

In general, compared to inorganic materials, organic materials have better transparency, are lighter in weight, are easier to form into films, and have both positive and negative chargeability, and are used in the manufacture of photoreceptors. It also has the advantage of being easy to use.

<Problems to be Solved by the Invention> Typical organic electrophotographic photoreceptors that have been proposed so far include, for example, polyvinylcarbazole and its derivatives, but these do not necessarily have film properties or flexibility. ,
Polyvinylcarbazole sensitized with biryllium salt dye (Japanese Patent Publication No. 4B-25658), polyvinylcarbazole, etc. are not sufficient in terms of solubility, adhesion, etc.
:, 2. 4. Although there are improved products such as those sensitized with 7-dolinitrofluorenone (U.S. Patent No. 34B4237), the basic properties, mechanical strength, high durability, etc. required for the photoreceptor listed above are not met. In the end, we are not getting enough of what satisfies our needs.

An object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity and high durability.

In particular, it is an object of the present invention to provide a photoreceptor that has excellent stability against temperature and humidity, has high charging characteristics, and exhibits almost no decrease in photosensitivity even after repeated use.

<Means for Solving the Problems> As a result of research into photoconductive materials having high sensitivity and high durability for the above-mentioned purposes, the present inventors have found that an enamine group-containing hydrazone compound represented by the following general formula is effective. This discovery led to the present invention.

That is, the present invention provides the following general formula (I) on a conductive support.
Provided is an electrophotographic photoreceptor characterized in that a photosensitive layer containing an enamine group-containing hydrazone compound shown in the following is formed.

(In the formula, A and B are hydrogen, an allyl group that may contain a substituent, an alkyl group that may contain a substituent, and a heterocyclic group that may contain a substituent. However, if A and B are hydrogen or an alkyl group at the same time) Except if .

A' is an allyl group which may contain a substituent or a heterocyclic residue which may contain a substituent, and R and R' are an alkyl group, hydrogen, or an allyl group which may contain a substituent.

However, the case where R and R' are both hydrogen is excluded. )especially,
Among the enamine group-containing hydrazone compounds represented by the general formula (I), the electrophotographic photoreceptor using the compound represented by the following general formula ([I) has better electrophotographic properties.

(In the formula, a + b are hydrogen, lower alkoxy group, lower alkyl group, tertiary amino group, a' is hydrogen, lower alkoxy group, alkyl group, halogen atom, R, R'
is an alkyl group, hydrogen, or an allyl group which may contain a substituent. However, the case where R and R' are both hydrogen is excluded. ) Further, in the electrophotographic photoreceptor, the photosensitive layer preferably contains a carrier transfer substance and a carrier generation substance,
Preferably, an enamine group-containing hydrazone compound represented by the above general formula (I) is used as the carrier transfer substance.

The enamine group-containing hydrazone compound represented by the general formula (I) according to the present invention can be synthesized by the following synthesis process.

(Blank below c) (Synthesis Step 1 (Synthesis Step 2) A hydrazone derivative can be easily obtained by heating and refluxing approximately equimolar amounts of the N derivative in a suitable solvent (e.g. ethanol). At this time, a small amount of acetic acid etc. may be added depending on the case. The reaction may be accelerated by adding it.

In synthesis step 2, approximately equal moles of the hydrazone derivative and the aldehyde derivative are mixed with P-toluenesulfonic acid,
Add a small amount of an acidic compound such as chlorine, heat to reflux, remove the water produced using a Dean-Stark tube, etc., and carry out the reaction.

Examples of the enamine group-containing hydrazone compound represented by the general formula (I) include those shown in Table 1 below.

(Left below) Table 1 Among these exemplified compounds, the one with excellent electrophotographic properties is A.
, B is a phenyl group substituted with an electron donating group, and A' is an exemplary compound of substituted and unsubstituted phenyl groups. Specifically, No 8) No 9 r N 010 +
No 11 No 12 + No 13. No14+N
o18. No.19. NO2O+ N021+No
25y No26. No. 27. No. 28 + N
o29 + No 30. No. 3 No. 37 +
No. 38 No. 39+ No. 44. No50
+No56+No61+NO62, NO66, etc.

The electrophotographic photoreceptor according to the present invention is obtained by incorporating one or more of the above-mentioned compounds into the photosensitive layer, and has extremely excellent performance.

In addition, other hydrazone compounds (for example, P N+N-diphenylaminobenzaldehyde-N, N-diphenylhydrazone, P-N,N-dibenzylaminobenzaldehyde-N,N-diphenylhydrazone) or 1.
3-butadiene compounds (e.g. 1-(P-diethylaminophenyl)414diphenyl-113-7"tadiene, 1.1-'; (P-dimethoxyphenyl)4+4-dipheny/I/-1,3-tadiene) or A photoreceptor having extremely excellent performance can also be obtained by mixing compounds such as ethylene compounds (for example, 1-P-N, N-diphenylaminophenyl 33-diphenylethylene).

Various methods are known for using these enamine group-containing hydrazone compounds as electrophotographic photoreceptors. In the form of a photoreceptor in which a binder resin is dissolved or decomposed and provided on a conductive support, or in the form of a laminate structure consisting of a carrier generation layer with high charge carrier generation efficiency and a carrier transfer layer. , the present hydrazone compound is added onto a carrier generating layer provided on a conductive support mainly with a pigment such as a sensitizing dye or an azo pigment, and if necessary, a chemical sensitizer or an electron-withdrawing compound is added, There is a photoreceptor in which a carrier transport layer is formed by dissolving or decomposing a binder, but it can be applied to either case.

Photoreceptors may be prepared using the compounds of the present invention with the aid of polymeric film-forming binders on supports such as metal drums, metal plates, conductively treated paper, or plastic films. Make it into a film.

In this case, in order to further increase the sensitivity, it is desirable to add a sensitizer or a substance that imparts plasticity to the polymerizable film-forming binder as described below to form a uniform photoreceptor film.

Various types of polymerizable film-forming binders can be used depending on the field of use.

In other words, in the field of photoreceptors for copiers or printers, polystyrene resin, polyvinyl acecool resin,
Preferred are polysulfone resins, polycarbonate resins, polyphenylene oxide resins, polyester resins, alkyd resins, polyarylate resins, and the like. These may be used alone or in combination of two or more. Among them, polystyrene.

Resins such as polycarbonate, polyarylate, and polysynthene oxide have a volume resistivity of 1013Ω or more, and also have excellent film properties, potential characteristics, and the like.

Further, the amount of these binders added to the enamine group-containing hydrazone compound of the present invention is in a weight ratio of 0.2 to 20 times, preferably in a range of 0.5 to 5 times, and when it is 0.5 or less, , the disadvantage that enamine group-containing hydrazone compounds may precipitate on the surface of the photoreceptor may occur.
If it becomes 5 times or more, it may lead to a significant decrease in sensitivity.

Especially alkaline binders are required for use in printing plates. An alkaline binder is an acidic group that is soluble in water or an alcoholic alkaline solvent (including mixed systems), such as an acid anhydride group, a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, or a sulfonimide group. It is a polymer substance with groups.

It is preferable that these alkaline binders usually have a high acid value of 100 or more. A binder resin with a high acid value easily dissolves or swells in an alkaline solvent.

Examples of these binder resins include styrene: maleic anhydride copolymer, vinyl acetate maleic anhydride copolymer, vinyl acetate crotonic acid copolymer, methacrylic acid: methacrylic ester copolymer, phenolic resin, methacrylic acid: styrene :Methacrylic acid ester copolymer, etc. Further, the proportion of these resins added to the photoconductive organic substance may be approximately the same as in the case of a photoreceptor for a copying machine.

Next, the sensitizing dyes added to the photosensitive layer include methylpiolet, crystalpiolet, and t.

Triphenylmethane dyes such as night blue and Victoria blue, erythrosine, rhodamine 81
Acridine dyes such as rhodamine 3R, acridine orange, and frapeosin; thiazine dyes such as methylene blue and methylene green; oxazine dyes such as fog blue and melt rub;
Other dyes include cyanine dyes, styryl dyes, pyrylium salt dyes, and thiobyrylium salt dyes.

Photoconductive pigments that generate charge carriers with extremely high efficiency through light absorption in the photosensitive layer include phthalocyanine pigments such as metal phthalocyanine, m-metal phthalocyanine, and halogenated metal-free phthalocyanine, perylene imide, and perylene acid anhydride. There are perylene pigments such as, azo pigments such as bisazo pigments and trisazo pigments, and other quinacridone pigments and anthraquinone pigments. In particular, those using metal-free fuclodianiline pigments, ticuronium phthalocyanine pigments, fluorene and fluorenone ring-containing bisazo pigments, bisazo pigments consisting of aromatic amines, and trisazo pigments as pigments that generate charge carriers provide high sensitivity. , provides an excellent electrophotographic photoreceptor.

The dyes mentioned above may also be used as charge carrier generating substances. These dyes may be used alone, but in many cases, charge carriers can be generated with even higher efficiency by coexisting with a pigment.

In addition to the spectral sensitizers listed above, it is sometimes necessary to add various chemical substances to prevent increases in residual potential, decreases in potential, and decreases in sensitivity due to repeated use. . These added substances include 1-taloloanthraquinone, benzoquinone, 2.3-dichloronaphthoquinone, naphthoquinone + 4.4'-dinitrobenzophenone, 4.4-dichlorobenzophenone, 4-nitrobenzophenone, and 4-nitrobenzalmarone. Dinitrile.

Ethyl α-cyano-β-(p-cyanophenyl)acrylate, 9-anthracenylmethylmalondinitrile, 1
Examples include -cyano-1-(P-nitrophenyl)-2-(Pthalolphenyl)ethylene and 2°7-sinitrofluorenone. In addition, antioxidants are added as additives to the photoreceptor.

An anti-curl agent, a leveling agent, etc. can be added as necessary.

The enamine group-containing hydrazone compound of the present invention is dissolved or dispersed in an appropriate solvent together with the various additives mentioned above depending on the form of the photoreceptor, and the coating solution is coated on the conductive support described above. and dried to produce a photoreceptor.

As a coating solvent, aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, a single solvent or a mixture of two or more solvents such as dioxane, dimethquinethane, and dimethylformamide, or alcohols, acetonitrile, and methyl ethyl ketone as necessary. It is possible to further add and use a solvent such as.

<Examples> Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these in any way.

Examples 1 to 5 An aluminum vapor-deposited polyester film (thickness: 75 μm) was used as a support, and a bisazo pigment represented by the following structural formula was applied onto the support using a polyvinyl butyral resin (
1% THF dissolved in Eslenoku B) manufactured by Nissin Chemical Industry Co., Ltd.
The same amount of resin by weight was added to the solution, and then dispersed in a paint conditioner (manufactured by Red Devil Co., Ltd.) together with glass beads having a diameter of 1 fl for about 1 hour, and then coated and dried by the Dr. Plaid method. The film thickness after drying is 0.
It was 2μ.

Exemplary compound N of the present invention is applied on this pigment layer (charge generation layer).
o8+ No14. + No18+ No21+ No
A 12% solution of 1 g of each of the 30 enamine group-containing hydrazone compounds and 12 g of polyarylate resin (Unitika U-polymer) dissolved in methylene chloride was applied using a squeegee doctor to form a resin hydrazone compound solid solution phase with a dry film thickness of 18 μm. (a cargo transport layer) was created.

The electrophotographic properties of the thus produced laminated electrophotographic photoreceptor were evaluated using an electrostatic recording paper tester (5P-428 manufactured by Kawaguchi Denki Co., Ltd.).

The exposure amount E100 (lux seconds) required for attenuation from -100V to -100V and the initial potential Vo (-volt) were measured.

Furthermore, the same device was used to apply and eliminate static electricity (static neutralization light: white light at 40°C).
The initial potential V (after performing the same operation 10,000 times, with one cycle of 1 second irradiation using Lux).

(-volt) and Eroo (lux seconds) were measured, and changes in vO and Eloo were investigated.

As a comparative example, an electrophotographic photoreceptor was prepared in the same manner except that a hydrazone compound having the structure shown below was used instead of the enamine group-containing hydrazone compound of the present invention to form a charge transfer layer. In addition, the electrophotographic characteristics of this photoreceptor were measured in the same manner.

Table 2 shows the above results. (for example described in Shown below.

(Left below) Example 6 X-type metal-free phthalocyanine (Dainippon Ink Co., Ltd. Fast Gemble-81) was deposited on an aluminum vapor-deposited polyester film.
20) Add 0.4 g to 30 ml of an ethyl acetate solution containing 0.3 g of vinyl chloride-vinyl acetate copolymer resin (Nislex M manufactured by Block Chemical Co., Ltd.), and disperse for about 20 minutes in a paint conditioner. A charge generation layer was formed by coating by the doctor playd method so as to have a thickness of 0.4 μm after drying.

On this charge generation layer, an enamine group-containing hydrazone compound of Exemplary Compound No. 44 (melting point: 157.0 to 159.0°C) was applied.
) A photoreceptor having a two-layer structure was prepared by stacking polyarylate layers containing polyarylate.

The energy required to halve the potential of the 780 nm spectral sensitivity of this photoreceptor (E) and the initial potential (vO) were determined.
O=880 volts, E,=2.1 C erg/c
! i) It was a highly sensitive and highly chargeable photoreceptor.

In addition, Sharp laser printer (WD-580)
P) was modified, the present photoreceptor was attached to the drum part, and continuous copying was performed 10,000 times, and no large change in value was observed compared to the first time when the initial potential was low.

Example 7 Styrene: ethyl methacrylate: methacrylic acid (styrene: ethyl methacrylate = 3: 1 weight ratio acid value = 170) and exemplified compound N011 (melting point: 153.5) were deposited on a surface-oxidized Al plate with a grained surface. 0℃) 2:
5% of the exemplary compound and 4-(P-diethylaminophenyl)-2,6-diphenylthiobilylium perchlorate (thiobilylium salt pigment). 0 of the exemplified compound
．． Each was added at a rate of 5% to make a 10% dioxane solution as a whole, and this solution was applied and dried using a squeegee doctor to prepare a single layer type photoreceptor with a film thickness of 7 μm.

Regarding the photoconductor created in this way, the above-mentioned 5P-4
The electrophotographic characteristics were evaluated according to No. 28.

Evaluation conditions: applied voltage -6KV, static -3 initial potential 540 (volts), light half-reduction exposure amount 15 (lux
Also, this photoreceptor was visualized with a developer (toner), and then an alkaline processing solution (3% triethanolamine, 10%
Ammonium carbonate and 20% average molecular weight 1190-210
When treated with polyethylene glycol), the toner-free areas were easily eluted, and by washing with water containing sodium silicate, a printing original plate could be easily prepared.

When offset printing was performed using this original plate, it was found that it could withstand printing of about 100,000 sheets.

The optimum exposure amount for obtaining a visible toner image was 500 lux for 15 seconds.

In addition, when creating the original printing plate, direct plate making was performed without using any base material.

<Effects of the Invention> According to the present invention, an electrophotographic photoreceptor with high sensitivity and high durability can be obtained. In particular, according to the present invention, it is possible to obtain an electrophotographic photoreceptor that has excellent stability against temperature and humidity, has high charging characteristics, and exhibits almost no decrease in photosensitivity even after repeated use.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized in that a photosensitive layer containing an enamine group-containing hydrazone compound represented by the following general formula (I) is formed on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, A and B are hydrogen, an allyl group that may contain a substituent,
These are an alkyl group which may contain a substituent, and a heterocyclic group which may contain a substituent. However, cases where A and B are both hydrogen or an alkyl group are excluded. A′ is an allyl group which may contain a substituent, a heterocyclic residue which may contain a substituent,
R and R' are an alkyl group, hydrogen, or an allyl group which may contain a substituent. However, the case where R and R' are both hydrogen is excluded. 2. The electrophotographic photoreceptor according to claim 1, wherein the enamine group-containing hydrazone compound represented by the general formula (I) is a compound represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) (In the formula, a and b are hydrogen, a lower alkoxy group, a lower alkyl group, and a tertiary amino group, and a' is hydrogen, a lower alkoxy group, An alkyl group or a halogen atom, and R and R' are an alkyl group, hydrogen, or an allyl group which may contain a substituent.However, this excludes cases where R-R' are hydrogen at the same time.) 3. The photosensitive layer is 2. The electrophotographic photosensitive material according to claim 1, comprising a carrier transfer substance and a carrier generating substance, and wherein an enamine group-containing hydrazone compound represented by the general formula (I) is used as the carrier transfer substance. body.