JPS5849951A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor high in sensitivity and durability, by using a specified disazo pigment especially for a charge generating layer. CONSTITUTION:A disazo pigment represented by formula 1 is contained especially in a charge generating layer to form a laminate photoconductive layer on a conductive substrate, thus permitting the obtained photoreceotor to be high in sensitivity and durability and able to form a copy identical to an original. In formulaI, A is a hydrocarbon group having a double bond either single or conjugated, or a heterocyclic group which may be condensed with or sibstituted by a hydrocarbon group or an aromatic ring which contains N in the conjugated double bonds as shown by the formulae 2-7; R2, R3 are H, halogen, lower alkyl or alkoxy, or NO2; R4 is H, halogen, or CN; and X is a residue forming a naphthalene, anthracene, carbazole, benzocarbazole, or benzofuran ring by condensing with a benzene ring, and it may be substituted by a group except OH and CONHR1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a specific disazo pigment. , 4
1. . +b*, it-+□8. .

As materials, those using selenium, cadmium sulfide, zinc oxide, etc. are widely known.

Examples of photoconductive materials include photoconductive polymers typified by poly-N-vinylcarbasol and organic photoconductive substances with low fractions such as 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadikesol. Electrophotographic photoreceptors using organic photoconductive substances have good film-forming properties and can be produced by coating, so they are extremely popular. A highly productive and inexpensive photoreceptor can be provided.

In addition, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as a pigment or dye to be used, and a wide range of studies have been made to date.

However, there are problems with sensitivity, durability, etc., and so far only a few have been put into practical use.

The purpose of the present invention is, first, to provide an electrophotographic photoreceptor containing a specific disazo pigment, secondly, to provide a highly sensitive electrophotographic photoreceptor, and third, a highly durable electrophotographic photoreceptor. It's about offering your body.

The present inventors have arrived at the present invention by noting that an electrophotographic photoreceptor using a disazo pigment represented by the general formula in a photosensitive layer is extremely useful in electrophotography.

The person in the general formula (1) may be fused or substituted with a hydrocarbon group having a single bond or a conjugated double bond, or a hydrocarbon group having a nitrogen atom within the conjugated double bond, or an aromatic ring. It is a good heterocyclic group and forms a conjugated double bond system with the adjacent azomethine group, (in the formula bird).

``Bird'' represents a group selected from the group consisting of hydrogen atoms, which may be the same or different; ).

R11 represents a linear alkyl group such as methyl, ethyl, propyl, butyl. X represents a residue that is condensed with a benzene ring to form a naphthalene ring, an anthracene ring, a carbazole ring, a penzcarno<'/-JS/ ring, and a sifurane ring, and the formed residue is a hydroxyl group, -CONHR
The present inventors proposed in Japanese Patent Application No. 55-21670 an electrophotographic photoreceptor using a disazo pigment having a substituent other than , and having the same main skeleton as the disazo pigment used in the electrophotographic photoreceptor of the present invention. However, the electrophotographic photoreceptor of the present invention has a linear alkyl group such as methyl, ethyl, propyl, butyl, etc. in general formula (1), so that the electrophotographic photoreceptor has high sensitivity and high durability. It has been discovered that a photographic photoreceptor can be obtained.

The disazo pigment represented by the general formula (1) can generally be synthesized by the following method. P-aminobenzaldehyde is converted into a di-7tyl compound by a conventional method, and then has the same meaning as the general formula (1). ) in the presence of an alkali, the diazonium salt of P-aminobenzaldehyde is isolated in the form of a borofluoride salt or zinc chloride double salt, and then a suitable solvent such as N , N-dimethylformamide, dimethyl sulfoxide, etc. in the presence of an alkali, the general formula (8
) to synthesize a monoazo pigment represented by the general formula (wherein, X has the same meaning as in general formula (1)).Next, the monoazo pigment and the general formula H , N-A-NH, (10) (in the formula, AFi has the same meaning as the general formula (1)), and the disazo pigment represented by the general formula (1) can be easily obtained. can get.

An electrophotographic photoreceptor containing an organic pigment on a conductive layer includes: (1) A layer in which a pigment is dispersed in a binder is provided on a conductive layer as disclosed in Japanese Patent Publication No. 52-1667.

■Tokuko Showa 47-1'8545. % Kaisho 47-30328
A charge transporting material such as that disclosed in , or furthermore, the material and an insulating binder (the binder itself is a charge transporting material,
A layer in which a pigment is dispersed in a charge transporting medium consisting of a conductive layer formed on a conductive layer.

■A conductive layer as disclosed in JP-A No. 49-105537,
Consisting of a charge generation layer and a charge transport layer containing organic pigments.

(2) An organic pigment added to a charge transfer complex as disclosed in Special Hj@49-91648. etc.

The electrophotographic photoreceptor of the present invention is characterized by containing a disazo pigment represented by the general formula (1), and can be applied to any type of electrophotographic photoreceptor having such characteristics, but the general formula (1) ) In order to increase the transport efficiency of charge carriers generated by light absorption of the disulfide pigments shown in (), it is desirable to use them as electrophotographic photoreceptors of type (1) and (2).

! A photoreceptor of type (2), in which charge carrier generation and transport functions are separated, is most desirable in order to take advantage of the characteristics of the pigment.

Therefore, this type 2 electrophotographic photoreceptor will be explained 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 can be either above or below the charge transport layer, but in an electrophotographic photoreceptor of the type that is used repeatedly, An adhesive layer may be provided as necessary for the purpose of improving adhesion with the conductive layer, charge generation layer, and charge transport layer mainly from the viewpoint of physical strength and in some cases from the viewpoint of chargeability.

As the conductive layer, a metal plate or metal foil such as aluminum,
Plastic films coated with a metal such as aluminum, aluminum foil laminated with paper, paper treated with conductivity, etc. are used.

As a material for the adhesive layer, trees such as Japanese pine, casein, polyvinyl alcohol, water-soluble polyethylene, and nitrocellulose are effective. The appropriate thickness of the adhesive layer is α1 to 5.0μ, preferably α5 to 3.0#.

The general formula (] is applied to the conductive layer or the adhesive layer applied to the conductive layer.
) After the disazo pigment shown in ) is made into fine particles, it is dispersed without a binder or, if necessary, in an appropriate binder solution, and the disazo pigment is coated and dried. It is desirable that the pigment particles have a particle size of 5.0μ or less, preferably zOμ or less, optimally α5μ or less.

The disazo pigment can also be applied by dissolving it in an amine solvent such as ethylenediamine.

Conventional methods such as blade, Mayer bar, spray, and dipping methods are used for application.

The thickness of the charge generation layer is 5. Below OA, preferably Hiro o, oi
~Log is desirable. When using a binder in the charge generation layer, the ratio of the binder in the charge generation layer is desirably 80% or less, preferably 40% or less, since a large amount of binder affects sensitivity10. Butyral, polyvinyl acetate, polyester, polycarbonate,
Various resins such as phenoxy resin, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, and polyvinyl alcohol are used.

A charge transport layer is provided on the charge generation layer provided like a layer. If the charge transport material does not have film-forming ability, a charge transport layer is formed by applying a solution prepared by dissolving a binder in a suitable solvent and drying it by a conventional method.

As charge transport substances, chloranil, bromoanil,
Tetracyanoethylene, tetracyanoquinodimethane,!
4.7-dolinitro9-fluorenone, 1417-titrani)O-9-fluoreno7.2.47-)linitro9-dicyanomethylenefluorenone, 2.45.7
-Titranitroxanthone, Z4B-) There are electron-withdrawing substances such as linitrothioxanthone, and polymerization of electron-withdrawing substances.

As a hole transport substance, pyrene, N-ethyl force A//
(Sole, N-isopropylcarbazole.

Hemethyl-N-phenylhydrazino-3-methylisoy
-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylethylcarbazole, N
, N-diphenylhydrazino-3-methylidene-10-
Ethyl fetch adiy, N,N-diphenylhydrazino-3-methylidene-1O-ethylphenol beef gin,
P-diethylaminobenzaldehyde N, N-diphenylhydrazo/, P-diethylaminobenzalf human-N -01-t 79-N-7x nylhydra7
'y, P-bi-tetradinopenzaldehyde N, N-diphenylhydrazone, 13.3-)limethylindolenine-W-aldehyde-N, N-diphenylhydrazone,
hydrazones such as P-diethylaminobenzaldehyde-3-methylbenzothiazolinone-2-hydrazone;

2. 5-bis(P-diethylaminophenyl)-13
, 4-oxadinzole, 1-phenyl-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[quinolyl(2))-3
-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2
) ) -3-(P-diethylaminostyryl)-5-
Pyrazoli such as (P-diethylaminophenyl)pyrazoline 7-0 2-(P--/ethylaminostyryl)-6-dinithylaminobenzosol, 2-(P-diethyladenophenyl)-4(P-dimethyl 7(/phenyl')-
Oxazole compounds such as 5-(2-chlorophenyl)oxazole.

Thiazole compounds such as 2-(P-dimethylaminostyrene)-6-dinithylaminopenzothiazole, bis(
Triarylmethane compounds such as 4-diethylamino-2-methylphenyl)-phenylmethane 1.1-bis(
4-N,N-diethylamino-2-,7'tylphenyl)hebutane, 1,1. Z 2-tetrakis (4-N,
Polyarylfurcanes such as N-dimethylamino-2-methylphenyl)ethane.

triphenylamine, poly-N-vinylcarbasol,
Holivinylpyrene, polyhinyl 77thracene, pyrene-
Formaldehyde resin, ethyl carbazole formaldehyde resin, etc. The charge transport material is not limited to those described here, and when used, the charge transport material may be 1. The thickness of the charge transport layer of It or a mixture of two or more is preferably 5 to 30 mm.

It is 8 to 20 Jl.

As the binder, acrylic pre-resin, polystyrene, polyester, polycarbonate, etc. can be used. A hole transporting polymer such as the poly-N-vinylcarbazole described above can be used as the binder for the low molecular hole transport substance. On the other hand, tysp4tzzt is used as a binder for low-molecular electron transport materials.
Electron-transporting gynomer polymers such as taK can be used.

When a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order and a good or poor photoreceptor is used, and the charge transport material is an electron transport material, it is necessary to positively charge the surface of the charge transport layer.
D. When exposed to light after charging, good electrons are generated in the charge-generating layer in the exposed area and injected into the charge transport layer, and then reach the surface and neutralize the positive charge, resulting in attenuation of the surface potential and unexposed -yt
An electrostatic contrast occurs between the IK and the IK. A visible image can be obtained by developing the electrostatic latent image formed by K in this manner with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then fixed after printing.

There is also a method of transferring the electrostatic latent image on the photoreceptor onto an insulating layer of transfer paper, developing it, and fixing it. The type of developing agent, the developing method, and the constant deposition method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. , which then reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between the surface potential and the unexposed area. At present, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

The ■ type photoreceptor is made by adding a disazo pigment represented by the general formula (, 1) to an insulating binder solution such as that used for the charge transport layer of the type ■ photoreceptor, coating it on a conductive support with a dispersion diameter, and drying it. can be obtained.

The ■ type photoreceptor is a charge transport material of the ■ type photoreceptor, and the insulating material used for the charge transport layer (ingu) is dissolved in a suitable solvent, and then a disazo pigment represented by the general formula (1) is added. Then, after dispersion, it is obtained by coating and drying on a conductive support.

■Type of photoconductor As described in ■Type of photoconductor, when an electron transport material and a hole transport material are combined, a charge transfer complex is formed, so in the solution of this charge transfer complex, a compound expressed by the general formula (1) is formed. It is obtained by adding a disazo pigment, dispersing it, coating it on a conductive support and drying it.

Each of the photoreceptors contains at least one pigment selected from the disazo pigments represented by formula (1), and can be used to increase the sensitivity of the photoreceptor originally used or to provide panchromatic The sensory body is expressed by the general formula (
It is also possible to use a combination of two or more types of disazo pigments shown in 1), or a combination with a charge generating material selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying but also for a wide range of electrophotographic applications such as laser printers and CRT printers.゛Next, on to the present invention! A synthesis example of the disazo pigment to be used will be specifically explained.

(Pigment 41) 4-(P-formylphenyl-a/)-3-hydroxy-
Naphthalene-2-carboxylic acid methylamide 5.07 g (
0,0152 mol) of DMF900+aJK was added thereto, and the mixture was heated and stirred to bring the liquid temperature to 70°C.

Next, 9 g (o, oo 7 s mol) of sulfuric acid hydrazine was dissolved in 14 ml of water, the temperature of the solution was raised to 11"at, and stirring was continued at the same temperature for 3 hours. The reaction solution was then filtered to remove the precipitated solids. f separately, then DMF300 all,
Using M E K 300 sJ, sequentially hot filtration and washing,
Furthermore, it was dried under reduced pressure with heat to obtain 4.73g of the desired pigment (collection: 941G).
) was obtained.

Infrared mold yield spectrum above 280°C Amide 1660fi1 Elemental analysis Molecular formula 〇, H, N, 04 Analysis value [%] C6fL86 6&80 H4,6O N 16.91 16.85 Other disazo pigments used in the present invention were synthesized in the same manner can do. Next, examples of electrophotographic photoreceptors using the disazo pigment of the present invention will be shown.

An aqueous polyvinyl alcohol solution was applied onto an aluminum plate having a thickness of 100 seconds and dried to form an adhesive layer with a coating weight of 0.8 f/WLs o.

Next, the above-mentioned IJn1 pigment, 5 g of each pigment listed in Table 1, and 10 g of Polyester Adhesive 49.000 (manufactured by Devon, solid content 20%) were applied on the adhesive layer after HF80-gt min. The coating amount after drying was 0.20 g/6L''.

Next, 1-[Viridyl(2))-3(P-diethylaminostyryl)-5-(P-diethylaminophenyl)virazo, phosphorus (charge transporting material) 51, polymethyl methacrylate resin (number average molecular weight 100,000) 5f TH
It was dissolved in F70a/ and coated on the charge generation layer, and the coating amount after drying was 10 #frL''.

The electrophotographic photoreceptor thus prepared was statically charged with corona at Q 5 KV using an electrostatic copying paper tester Model 18F-428 manufactured by Kawaguchi Electric Co., Ltd., and held in a dark place for 10 seconds. It was exposed to light at an illuminance of 5/ux, and the charging characteristics were examined.

The initial potential is Vo (-V), the potential retention rate for 10 seconds in the dark is BY (*), and the half-decay exposure amount is B V2 (lux,
5ec), the charging characteristics of each photoreceptor were investigated, and the results were also positive. −
4,4"-Dioxydiphenyl-2,270rnj, and the coating amount after coating and drying was 12 g/llr. Charge measurement was carried out in the same manner as in Example 1, and the specific values are as follows. 0 However, the polarity was set to e.

Vo +500V approx. 83% 'B'4 131ux-see Examples 32 to 43 ・=* 5 g of /I61 pigment used in Example 1 and 2 g of butyral resin (degree of butyralization S mol-) were mixed with ethanol 95
After dispersing with mJK11 liquid, it was applied to the aluminum surface of an aluminium-deposited mylar film, and after drying, the charge transporting material shown in Table 2 was 5 g raw rough phenoxy, with an OJK working amount of 0.2 g/Wt. Resin υ00 manufactured by Bakelite PKHH) 5 g tt A solution dissolved in 10 ml of T HF was applied to the above-mentioned charge ray layer Klk cloth, and dried until the coating amount was 11
The photoreceptor thus prepared, on which a charge transport layer of g# was formed, was subjected to charge measurement in the same manner as Actual Bar Example 1, and the characteristic values are shown in Table 3.

Table 3 W electric characteristics Examples 1 and 8 for Aluo Shishi tube with a diameter of 120III
．． The adhesive layer, the charge generation layer, and the charge transport layer were sequentially laminated in the same manner as in 21 to create the photosensitive drums 44 to 46. Negative corona charger, exposure optical system, developer,
Using a transfer charger, a static elimination exposure optical system, and a cleaner (sequentially deployed), set the initial dark potential to esso v,
-A durability test was conducted using component magnetic developer, and after 20,000 copies of each drum, a beautiful copy that was faithful to the original was obtained. Relationship between 117J' and 117J' Nichiichi Permit Office Nagatomi Island FFL Haruki Prefecture Case Showa 56 Metropolitan 4I Permit No. 117078 龜AM06 Electrophotographic Photoreceptor Case 41WIF Applicant Residence Yrt Tokyo? giv6chom5es No. Tsuvia Co., Ltd. Representative Tomomasa Matsui Residence Shimo-Kyuko, Ota-ku, Tokyo 14! -! 4)-26,
Full text of the specification to be amended 7, Reprint of the specification of contents to be amended (no change in content)

Claims (1)

[Scope of Claims] (1) An electrophotographic photoreceptor characterized by using a disazo pigment represented by the following general formula (1). General formula (i) In the formula, one person may be a hydrocarbon group having a single bond or a conjugated double bond system, or a hydrocarbon group having a nitrogen atom in the conjugated double bond, or may be fused or substituted with an aromatic ring. It is a good heterocyclic group and forms a conjugated double bond system with the adjacent azomethine group, and horse represents a straight-chain alkyl group. X represents a residue that forms a naphthalene ring, anosthracene!, carbazole ring, benzcarbazole ring, or benzo7tine ring when combined with the densine group. L% The formed residue is a hydroxyl group,
It may have substituents other than eONH. (In the formula, 82.⇠ is a hydrogen atom, a halogen atom, which may be the same or different,
It is selected from the group consisting of a lower alkyl group, a lower alkoxy group, and a nitro group, and 雇 represents nine groups selected from the group consisting of a hydrogen atom, a halogen atom, and a cyano group. ) The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is selected from the following. (3) An electrophotographic photoreceptor comprising a conductive layer, a charge generation layer, and a charge transport layer, wherein the charge generation layer uses a disazo raw material represented by the general formula (1). (4) The electrophotographic photoreceptor according to claim 3, characterized in that a 'x7 pigment of the following 1-formation is used in the charge generation layer. (5) An electrophotographic photoreceptor according to claim 3, characterized in that a disazo pigment having the following structure is used in the charge generation layer.