JPS61107248A - Laminate type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrophotographic characteristics by successively laminating a charge transferring layer having positive hole transferring action and a charge generating layer contg. a photoconductive azo pigment and a specified charge transferring material having positive hole transferring action on an electrically conductive support. CONSTITUTION:An azo pigment having a phenolic OH group is used as a photoconductive azo pigment used in a charge generating layer, and an azo pigment represented by formula I is especially effective. In the formula, l=2 or 3, A is a bivalent org. group forming a conjugated double bond system between carbon atoms having a bonded azo group, and B is a coupler having a phenolic OH group. A hydrazone type charge transferring material is used as a specified positive hoe transferring material used in the charge generating layer, and a material represented by formula II is especially preferable. In the formula, D is a phenyl group which may have a substituent other than a substituted amino group or a carbazolyl group which may have a substituent but is not N-substituted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electron-donating Jc photoreceptor, in particular at least a charge transport layer and a charge generation layer t'' sequentially formed on a tetraelectric support. The electrophotographic photoreceptor VcrJkJ has a surface layer as a charge generation layer.

BACKGROUND OF THE INVENTION Hitherto, electrophotographic photoreceptors using inorganic materials such as selenium, cadmium sulfide, and zinc oxide as photosensitive components have been known.

On the other hand, since the discovery that certain organic compounds exhibit photoconductivity, many organic photoconductors have been developed. For example, organic photoconductive polymers such as poly-H-vinylcarbazole, polyvinylanthracene, carnosol, anthracene, pyrazolines, oxadiazoles,
Low-molecular organic photoconductors such as hydrazones and polyaryl alkanes, 7-talocyanine pigments, azo pigments, cyanine dyes, polycyclic quinone pigments, rylene pigments, indigo dyes, thioindigo dyes, and squaric acid methine dyes Organic pigments and dyes are known. In particular, organic pigments and dyes that exhibit photoconductive t-V are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded. Photoconductive organic pigments and dyes have been proposed. For example, US Pat. No. 4,123,270, US Pat. No. 4,247
No. 614, No. 4251613, No. 4251614
No. 425682), No. 4260672, No. 4268596, No. 4278747, No. 42
Electrophotographic photoreceptors that use a disazo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer that functions as a charge trapping shield and a charge trapping shield, as disclosed in No. 93628, are known. There is.

Particularly with respect to azo pigments, there are many variations in the material, and in recent years there has been much research and some have been put into practical use.

In its use, it has an M structure in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support, and the charge transport material used in the charge transport layer is a material with strong electron donating property, and the hole transport property is used. , it was common to use the photoreceptor Teiden.

Reasons for this include the fact that there are almost no electron-carrying materials with excellent properties, and that they are not used for convenience due to cancerous pollution. ,・)... Negative corona release - Gyōnatsu FC Togo, the amount of ozone generated is large, and it is necessary to attach an ozone filter jacket to the main body of Hakishakoko, which is a factor in increasing costs. Furthermore, as ozone filters gradually deteriorate over the years, regular maintenance such as filter replacement is required.

Furthermore, negative corona discharge tends to cause discharge unevenness due to dirt on the discharge wire, etc., which causes image unevenness. Furthermore, the generated ozone has a negative effect on the durability life of the OPC. e
Problems such as deterioration of the material on the surface of the photoreceptor, which generates a large amount of ozone during charging, and a layer of ionic substances generated by corona charging on the photoreceptor, are noticeable. Otherwise, the overall potential decreases, causing local or overall image blurring or image defects in copied images formed by electrophotography.

On the other hand, positive corona discharge generates about 175 to 1/10 the amount of ozone compared to negative corona discharge, and discharge unevenness may occur due to dirt on the discharge wire, etc. It is also extremely advantageous in terms of photoreceptor life.

As described above, e-charging has many disadvantages, and there is an urgent need to develop an e-type photoreceptor.

One method for producing an e-charged laminated photoreceptor is to sequentially laminate a hole-transporting charge transport layer and a charge generation layer on a conductive support.

However, if the thickness of the charge generation layer is increased by 50%, carriers generated by light will be less likely to be trapped in the charge generation layer, the optical memory will become larger, and the bright area potential will increase during repeated use, etc. is large, so usually a1~0.5μ
It is customary to have an extremely thin film thickness of about 100 ml.

However, when the charge generation layer is on the surface layer of the photoreceptor, charging, ill-exposure, development, transfer of the toner image to a transfer member such as paper or plastic film, separation of the transfer member from the photoreceptor, cleaning, and before and after cleaning. When the photoconductor of this eye is used for copying methods such as static elimination, part of the surface of the photoconductor will be scratched during processes such as development, transfer, cleaning, etc. where parts come into contact with the photoconductor. At present, there is a problem in which the charge generation layer is scraped away and exhibits no sensitivity in extreme cases where the reaction change is extremely large.

Problems to be Solved by the Invention The first object of the present invention is to provide a highly sensitive electrophotographic photoreceptor for e-charging in which at least a charge transport layer and a charge generation layer are successively laminated on a conductive support. There are many.

A second object of the present invention is to provide an electrophotographic photoreceptor for Φ charging, which has improved electrophotographic characteristics and has at least a charge transport layer and a charge generation layer sequentially laminated on a conductive support.

A fifth object of the present invention is to provide an e-coated material with improved durability, which comprises sequentially laminating at least a charge transport layer and a charge generation layer on a conductive support.
An object of the present invention is to provide an electrophotographic photoreceptor for charging.

1 Next means for solving the problem, operation, effect of the invention This object of the present invention is to provide at least a hole-transporting charge transport layer and a charge generation layer f:/I [next lamination] on a conductive support. ,
This is achieved by incorporating a photoconductive azo pigment and a specific hole-transporting charge transport material into the charge generating layer.

The reason why a particular charge transporting material must be selected is believed to be that there is selectivity in carrier injection from the photoconductive azo pigment, which is the carrier generating material, to the charge transporting material in the charge generating layer.

If an attempt is made to increase the physical strength of the photoreceptor surface by increasing the amount of binder resin in the charge generation layer by 1 ton, the transportability of carriers in the charge generation layer will be significantly reduced, resulting in a decrease in sensitivity, deterioration of optical memory, and brightness during long-term use. It is customary to imitate an increase in part potential, etc.

However, by incorporating a specific hole-transporting charge transporting material into the charge generation layer, it has become possible to ensure sufficient carrier transportability within the charge generation layer even when the amount of binder is increased. Therefore, a photoreceptor with a strong physical strength on the surface of the photoreceptor and excellent sensitivity and optical memory can be obtained.

Furthermore, the object of the present invention is achieved (the abrasion of the photosensitive layer during long-term use is significantly reduced, and a photoreceptor with less change in sensitivity during long-term use is possible).

As the photoconductive azo pigment used in the present invention, an azo pigment having a phenolic OH group is used. Specifically, an azo pigment represented by the general formula % (%) is particularly effective for M. t represents 2 or 3.In the formula, the person is a divalent organic group or N6) in which the carbon atoms to which the azo group is bonded form a conjugated double bond system.
It is characterized by the following.

A specific example of a divalent organic group is etc. can be mentioned.

R1-R28 are hydrogen, halogens such as chlorine, bromine and iodine, alkyl groups such as methyl, ethyl and propyl, flukoxy groups such as methoxy and ethoxypropoxy, benzyl, 7
Indicates enethyl aralkyl group, nitro group, cyano group, etc.

and aryl groups such as phenyl and naphthyl.

Specific examples of divalent organic groups include the general formulas (11-
(The group represented by 83 may also include a group having a phenylazo group which may have an enzymatic group on both sides.

m%n indicates O or 1 and may be the same or different.

In the general formula (13), B represents a coupler having a phenolic OH group, and specifically, HU is particularly effective.

-R In formula (10), Y represents a residue necessary for condensation with a benzene ring to form a polycyclic aromatic ring such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, etc. .

ztfi in general formulas (13) and (14) represents an aromatic hydrocarbon divalent group or a heterocyclic divalent group containing an N atom in the ring.

R2O''R52 represents an alkyl group, an aralkyl group, or a 7-aryl group represented by R1-R29.The 7-aryl group in the 7-aryl group or an aralkyl group represents an alkyl group, an alkoxy group, a nitro group, or a cyano group represented by jjKRj to R29. , halogen, aralkyl group, aryl group or dimethylamino,
Substituted amino groups such as diethylamino and dibenzylamino may be substituted.

A hydrazone-based charge transporting material is used as a specific hole transporting material used to increase the generation of abrasive charge in this +6 light, and a particularly preferable material among the hydrazones is shown by the following general formula.

In the formula, phenyl may have a substituent t-'N' in addition to the t-substituted amino group! ! lit%In addition to the Nlt substituent, the substituent ftVt represents an optional carbazolyl group.

Specifically, D is y)il & selected.

R%R' in the general formula is an alkyl group such as methyl, ethyl, propyl, butyl, a 7-ralkyl group such as benzyl or phenethyl, or a 7-ralkyl group such as phenyl, α-naphthyl, β-7-tyl, etc.
The aryl group in the aryl group and the aralkyl group represents a chlorine% bromine, a halogen such as 1:i-, an alkyl group such as methyl, ethyl t-propyl, an alkoxy group such as methoxy, ethoxy, propoxy, dimethylamino, diethylamino , dipropylamino, dibenzylamino, etc.).

R55%R54%R4Q in formulas (17) to (19) is R
, R' has the same meaning as alkyl, aralkyl, or aryl group, and R35 to R3tp and RJl are alkyl groups such as methyl, ethyl, and propyl, alkoxy groups such as methoxy, ethoxy, and propoxy, chlorine, bromine, Indicates halogen such as iodine.

Specific examples of the hydrazonated compound used in the present invention are shown below.

The azo photoconductive pigment used in the compound charge generation layer is dispersed in a layer liquid system consisting of a suitable binder resin and a hydrazone charge transport material, and then coated on the previously prepared charge transport layer. A charge generation layer can be formed.

The binder that can be used when forming the charge-generating JfII by coating can be selected from a wide range of insulating resins, and poly-N-vinyl carbazole, polyvinyl ant 2
You can also choose from organic photoconductive polymers such as hexafluoride and polyvinylpyrene.

Preferably, in addition to the photoconductive polymer, polyvinyl butylar, polyarylate (such as a polymer of bisphenol A and 7-talic acid), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin,
Polyacrylamide = 8, polyamide, urethane wood, epoxy I! Insulating resins such as F resin can be used.

The resin contained in the charge generation layer is preferably 10 to 80% by weight, more preferably 60 to 60% by weight from the viewpoint of the physical residual layer on the surface of the photoreceptor and carrier transportability within the charge generation layer. It is very likely that this will be the case.

The proportion of the charge #4 transporting material in the charge generation layer is preferably 10 to 70% by weight, more preferably 20 to 60% by weight for the same reason as the resin amount.

Charge generation layer (ratio of azo photoconductive pigment included: 11
! M is preferably 0.3 to 80% by weight.

The solvent used in the paint for the charge generation layer is selected based on the resin used, the solubility of the charge transport material, and the dispersion stability of the charge generation material.
It is also necessary to choose from i things.

Specific wi solvents include alcohols such as methanol, ethanol, and isopropanol, acetone, and MEi.
K% Ketones such as cyclohexanone M% M, M-Dimethylformamide, Pi, amides such as N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, methyl acetate, acetic acid Which ester is ethyl, @, chloroform,
Aliphatic halogenated hydrocarbons such as methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene, or aromatic groups such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. Drying is preferably carried out by drying to the touch at room temperature and then drying on a heated dry bed. The heating conversion can be carried out at a temperature of 30 to 200° C. for a time ranging from 5 minutes to 2 hours, either stationary or under blown air.

The charge transport layer is connected to the above-mentioned "#t# generation part" and the regional IC', and in the presence of the "#t# generation field", the charge carriers injected from the charge carriers are taken, and these charges are transferred. It has the ability to transport carriers to the surface of a conductive support or to the surface of a sublayer with a conductor interposed between the layer and the charge transport layer.

The charge transport layer includes a charge transport material with hole transport properties.

used.

Examples of the hole-transporting substance include pyrene, N-ethylcarbazole, N-inopropylcarbazole, hydrazones including the hydrazone described in the section of human 91 used in the charge generation layer, 2,5-bix(p-diethylamino phenyl)
-1,3,4-oxothadiazole, 1-phenyl-3
-(P-diethylaminostyryl)-5-CP-diethylaminophenyl)pyrazoline, 1-[quinolyl (2)
]-3-CP-diethylaminostyryl)-5~(P-
diethylaminophenyl]pizzoline, 1-[pyridyl(2))-5-CP-diethylaminostyryl)-5
-CP-diethylaminophenyl]pyrazoline, 1-(
6-methocypyridyl (2)) -3-(p-diethylaminostyryl)-5-CP-diethylaminophenyl)pyrazoline, i-(pyridyl (37) -3-(p
-diethylaminostyryl)-5-CP-diethylaminophenyl)pyrazoline, 1-[lepidil (2))-3
-(p-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline-1-[pyridyl+2]
)-3-CP-diethylaminostyryl)-4-methyl-5-(P-diethylaminophenyl]pyrazoline, 1
-[Pyridyl (2)) -5-(α-Methyl-P-diethylaminostyryl)-5-CP-diethylaminophenyl)pyrazoline, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl-5-( P-diethylaminophenyl]pyrazoline.

1-phenyl-3-(α-benzyl-P-je 1
Pyrazolines such as tylaminostyryl)-5-CP-diethylaminophenyl) pyrazoline and spiropyrazoline! , 2-(p-diethylaminostyryl)-6-ethylaminobenzoxazole, 2-(P-diethylaminophenyl)-4-(P-dimethyl7minophenyl)-
Oxazole compounds such as 5-(2-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)-
Thiazole compounds such as 6-dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-M,H-diethylamino-2 -methylphenyl)hebutane, 1,1,2,2-tetrakis(4-N,N-dimethylamino-2-methyl-7enyl)
Examples include polyarylalkane such as ethane, triphenylamine tpolyN-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, helene-formaldehyde resin, ethylcarbazole formaldehyde 4jHHk1, and the like.

1. et'''et''0'' 15 transportation 5 quality 0 other 7゛ゞ''
Inorganic materials such as selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Also, t these charge transport substances are 1′m or 2)j1
The above can be used in combination.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as binders include acrylic resins, polyarylates, polyesters, polycarbonates,
Polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone,
Examples include insulating resins such as polyacrylamide-polyamide monosalt rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Since charge transport iv1 has a limit in which it can transport charge carriers, it is not possible to increase the film thickness more than necessary. Generally, it is 5 to 30μ, but the preferred range is 8
~20μ. When forming the charge transport l- by coating, the above-mentioned suitable coating method can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having one conductive layer. Examples of substrates having a conductive layer include 1. The substrate itself is conductive.1
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium1
Nickel, indium, gold, platinum, etc. can be used, and other materials such as aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-cum-tin oxide alloy, etc. can be used to form a film by vacuum evaporation. For example, polyethylene, polypropylene,
polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (yI
For example, a substrate coated on a plastic with a suitable binder (e.g., carbon black, silver particles, etc.), a substrate made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the charge transport layer.

The undercoat layer is made of casein, polyvinyl alcohol, cellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, composite nylon, alkoxymethylated nylon, etc.),
It can be formed from polyurethane, gelatin, aluminum oxide, etc. The thickness of the undercoat layer is suitably (L1 to 5μ, preferably (L5 to 3μ).

The electrophotographic photoreceptor used in the present invention is subject to deterioration due to ultraviolet rays, ozone, etc., dirt due to oil, etc., scratches due to cutting powder of metal, etc., and damage to the photoreceptor due to photoreceptor contact members such as developing members, transfer members, cleaning members, etc. A protective layer or an insulating layer may be further provided on the charge generation layer for the purpose of preventing scratching. In order to form an electrostatic latent image on this layer, it is likely that the surface resistance is 10<11 >[Omega] or more.

The skin protector used in the present invention is made of polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene/butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer, etc. The photosensitive layer can be formed by dissolving a resin in a suitable organic solvent and applying the solution onto the photosensitive layer and drying it.

Additionally, additives such as ultraviolet absorbers can be added to the resin liquid.

At this time, the thickness of the protective layer is generally in the range of 0.05 to 20μ, particularly preferably in the range of α2 to 5μ.

The layer structure of the electrophotographic photoreceptor of the present invention is as shown in the drawings.

When a conductive layer, a charge transport layer, and a charge generation layer are laminated and a good/bad photon is used, the charge transport substance consists of a hole transport substance, so the surface of the charge generation layer must be positively charged. When exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. On the other hand, electrons generated by exposure reach the surface and neutralize the positive charges.

Attenuation of the surface potential occurs and electrostatic contrast occurs between the surface potential and the unexposed area. A visible image is obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be developed and fixed after being transferred to paper, plastic film, etc.

Seriously, the silence on the photoreceptor! A method may also be used in which the latent image is transferred onto an insulating layer of transfer paper, developed, and fixed. The type of developer, the developing method, and the fixing method may be any known ones or any of the known methods, but are not limited to specific ones.

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

The present invention will be explained below according to examples.

Examples 1 to 17 Ammonia aqueous solution of casein on an aluminum plate □ (casein 11.2P, 28% ammonia water 1js water 222
The film was coated with a Mayer bar so that the film thickness after drying was 1.0 μm and dried.

Next, hydrazone compound 5f of the exemplified compound boiled 1 and polymethyl methacrylate resin (number average molecular fL: 100
,000) 5ft-benzene was dissolved in 70dK and applied onto the charge generation layer using a Mayer bar so that the film thickness after drying would be 12μ, and dried to form a charge transport layer.

Next, hydrazone compound 45f of exemplified compound/I62 and polymethyl methacrylate resin (number average molecule i 100,000)
Disazo pigment 1 represented by 45P chlorobenzene 800
0f was added, and the mixture was dried in a sand mill for 1Q hour. This dispersion was coated onto the previously formed charge transport layer by a dipping method and dried to form a charge generation layer with a baseness of 5μ.
A photoreceptor was created.

Separately from the photoreceptor of Example 1, the hydrazone compounds used in the charge generation layer were selected from Exemplary Compounds 2 to 13.16.18.20.
．． Photoreceptors of Examples 2 to 17 were produced in exactly the same manner as Example 1 except that Example 2) was replaced.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
Photocopy paper testing device Mode/, 13P-42
The corona band was statically charged at +5KV using V8, held in a dark place for 1 second, and then illuminated with f51. Exposure with ux and the band't! L characteristic f: Investigated.

The band's curve characteristics are t surface potential (/Vo) and the exposure t(li
) t-measured. The results are shown in Table 1.

1st table j l 600
452 2
580 4, Q3 S
590 404
4 610 4.15
5 570 4
, 46 6 590
4.6f3 8
610 439 9
590 5810
10 600 A611
11 570
4.912 12 5
90 4.2) 3 13
580 4.414
16 610 &2)5
18 590 6
．． 316 20 58
0 As shown in Table 58, the photoreceptor of the present invention has good ef tolerance and e band! The sensitivity of the time was shown.

Comparative Example 1 A photoreceptor was prepared in exactly the same manner as in Example 1, except that the hydrazone compound was not used in the charge generation layer of Example 1, and the photoreceptor was loaded.

Surface potential: +560v 1% 18 Lux@aea Compared to the photoreceptor of the present invention, the sensitivity is extremely low and it has no practical use at all.

Examples 18 to 28 A polyvinyl alcohol film having a thickness of 1.1 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film by dip coating.

Next, using the specific charge generating material used in the charge transporting 1% charge generation layer of Example 1 and the materials shown in Table 2 as the charge storage material, the photoconductors t-:1 of Examples 18 to 28 were fabricated. It was prepared in exactly the same manner as in Example 1 and the potential was measured. The fruit boxes are shown in Table 3. Optical memory has been added as a potential measurement item.

By exposing a photoreceptor to light before charging, the charging potential of a photoreceptor with a strong optical memory decreases significantly, resulting in a poor image! ! An extreme decrease in image density or white areas in the pre-exposed area will cause development.

The evaluation method for optical memory is 6Q Q tax 3.
A pre-exposure of 10 minutes was applied, and the difference in surface potential (ΔvO) decreased compared to when no pre-exposure was applied.

Table 3 18580, 4.9 2t) 19610 5.6 30 22590 5950 23600 4.0 20 24620 4.5 10 25610 i3 20 26580 A8 20 27590 4.9 30 Comparative Examples 2-5 Example 18.23.2 6 Comparative photoreceptors 2 to 5 were prepared in exactly the same manner as in Example 18, 23, 26, and 27, except that the charge transport material shown in Table 4 was used in place of the human 1-2 sine compound in the charge generation layer of .27. did. Table 5 shows the potential measurement values.

Table 4 Comparative example Charge transport material list used for charge generation layer
5 5 610 10 9t1 When hydrazone in the charge generation layer is replaced with a charge transporting material other than hydrazone, the sensitivity of the photomemory is significantly worse than in the case of hydrazone. A system that uses a combination of generated materials and hydrazone,
proved to be extremely effective.

Example 29 An aluminum cylinder with a diameter of 60 al was coated with the same coating liquid except that the binder resin used in the charge generation layer of Example 1 was replaced with 1C of polycarbonate smoked resin (number average molecular weight: 75,000). ! An electrophotographic photoreceptor was prepared by sequentially stacking each layer using the dipping method.

Canon Co., Ltd.'s e-band PPO copy disc (prototype =>
Using 'it, -vJA8's 1# sheet was set to Φ700V with the initial bright area potential set to Φ100V, and an e-charging toner was used to print 10,000 sheets, and the potential was measured after the durability was left overnight.

The 4-year-old prototype drum for testing includes a corona charger for 8 Firefly A, an exposure area, an yl image area, and a transfer @ Firefly'h.
It is equipped with a corona charger, blade cleaner, and pre-exposure lamp.

The results of potential measurement are initial durability potential (+V) durability after 10,000 sheets (+V) dark area position 700 720 light area potential 100
Sensitivity fluctuations due to the 130-print printing cycle were small, and the image had no blurring or image defects due to ozone deterioration, and no discharge unevenness due to corona wire contamination was observed, and a beautiful image was obtained even after the 10,000-sheet printing cycle.

Example 30 A methanol bath of polyvinyl butyral resin (saponification degree of 100, butyralization degree of 75, weight coefficient average molecular weight of 30,000) was prepared in exactly the same manner as in Example 29, and was placed on a good and bad light body.
A protective layer having a dry film thickness of 3 μm was formed by coating by the tx method.

Using this photoconductor and using the same equipment as in Example 29, a durability test of 20,000 images was carried out in exactly the same manner as in Example 29, but the images obtained were extremely impressive. It has been proven that.

[Brief explanation of the drawing]

1 to 4 show the layer structure of the electrophotographic photoreceptor of the present inventor. Reference numeral 1 is an azo photoconductive pigment, 2 is a binder resin + hydrazone carrier transport material, and 3 is a charge generation layer 4 that is a charge -x! In the s-layer, 5 is a conductive support, 6 is a bottom layer, and 7 is a protective layer or an insulation layer.

Claims (3)

[Claims] (1) At least a hole-transporting charge transport layer and a charge generation layer are sequentially laminated on a conductive support, and the charge generation layer contains an azo photoconductive pigment and a hydrazone charge transport material. A laminated electrophotographic photoreceptor. (2) The azo photoconductive pigment used in the charge generation layer is a pigment represented by the general formula A-(N=N-B)_l(I), and the hydrazone charge transport material used in the charge generation layer is a pigment represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) However, in the general formula (I), A is a divalent organic group in which the carbon atoms to which the azo group is bonded form a conjugated double bond system or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ indicates a coupler with a phenolic OH group, and l
represents 2 or 3, and in general formula (II), R represents a phenyl group that may have a substituent other than the substituted amino group, or a carbazolyl group that may have a substituent other than the N substituent. ,
The laminated electrophotographic photoreceptor according to claim 1, wherein R' is a material representing an alkyl group, an aralkyl group which may have a substituent, or an aryl group. (3) A laminated electrophotographic photoreceptor according to claim 1 or 2, wherein a protective layer or an insulating layer having a surface resistivity of 10^1^1 Ω or more is provided in the charge generation layer.