JPS5933455A - electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To enhance reproductivity of the image of a red original, by incorporating a specified disazo compd. in a charge generating layer in a laminate type electrophotographic receptor obtained by forming the charge generating layer and a charge transfer layer on a conductive substrate. CONSTITUTION:A charge generating layer 22 contg. a disazo compd. represented by formula I in which X, Ar are each an optionally substd. hetero ring on a conductive substrate 11 of an aluminum plate or the like. The intended electrophotographic receptor is obtained by forming on this layer a transfer layer 33 contg. a charge transfer substance represented by formula II in which R1, R2 are each methyl, ethyl, or the like, and R3 is H, chlorine, 1-4C alkyl, or the like. Said diazo compd. of formula I is obtd. by diazotizing 1,5-diaminoanthraquinone and coupling it with a corresponding coupler, such as naphthol AS or its derivs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor for electrophotography, and more specifically, the present invention relates to a photoreceptor for electrophotography. Penetrates the generation layer.

) and the charge generated by the charge generation layer] from a layer containing a substance (hereinafter referred to as charge transport layer) that receives the body and transports it (hereinafter referred to as the charge transport layer) The present invention relates to a laminated electrophotographic photoreceptor.

Conventionally, photoreceptors for electrophotography include inorganic ones that use selenium and its alloys, or photoreceptors that have dye-sensitized zinc oxide dispersed in a binder resin.
In addition, organic substances include 2,4.7-)dinitro-9
-Fluorenone (hereinafter referred to as T'NF 9°) and poly-
A typical example is one using a charge transfer complex with N-vinylcarbazole (hereinafter referred to as pVK).

However, while these photoreceptors have many advantages, they also have various disadvantages.

For example, the currently widely used selenium photoreceptor has difficult manufacturing conditions and high manufacturing costs, is difficult to process into an R-rut shape due to lack of flexibility, and is sensitive to heat and mechanical shock. Therefore, care must be taken when handling. In addition, zinc oxide photoreceptors can be manufactured by coating them on a support using inexpensive zinc oxide, so the cost is low;
Generally, it has low sensitivity, mechanical defects such as surface smoothness, hardness, tensile strength, and abrasion resistance. There are many problems. Furthermore, a photoreceptor using a charge transfer complex of % TNF and PVK has low sensitivity and is unsuitable as a photoreceptor for high-speed copying machines.

In recent years, extensive research has been carried out in order to eliminate the drawbacks of these photoreceptors, and in particular, organic type photoreceptors have been proposed. Among them, a type 1 photoreceptor is one in which a thin film of an organic pigment is formed on a conductive support (formed as a charge generation layer), and a layer mainly composed of a charge transport substance (charge transport layer) is formed on this. It is attracting attention as a photoreceptor for plain paper copying machines because it generally has higher sensitivity and stable chargeability than other photoconductors, and some of them are in practical use. .

This type of conventional laminated photoreceptor includes (1) a thin layer of a perylene derivative vacuum-deposited as a charge generation layer and an oxadiazole derivative as a charge transport layer (see U.S. Pat. No. 3,871,882); ), (2) A thin layer formed by coating an organic aban solution of chlordian blue as a charge generation layer and a hydrazone compound as a charge transport layer (Japanese Patent Publication No. 55-4238
(3) A thin layer formed by coating an organic solvent dispersion of a distyrylbenzene-based disazo compound as a charge generation layer and a hydrazone compound as a charge transport layer (Japanese Patent Application Laid-Open No. 1983-1999) -84943) etc. are known.

-However, it is true that the conventional laminated type photoreceptor has many advantages, but also has various disadvantages.

In the photoreceptor using the perylene derivative and oxadiazole derivative shown in (1), the charge generation layer is formed by vacuum evaporation, which increases the manufacturing cost.

The photoreceptor using chlordiane blue and hydrazone compound shown in (2) requires the use of an organic amine (e.g. ethylenediamine), which is difficult to handle under general pressure, as a coating solvent to form the charge generation layer. There are many drawbacks to the above. Furthermore, since the photosensitive wavelength range in the visible range ranges from approximately 450 to 660 nm, the image reproducibility of red originals was poor. Therefore, when actually implementing it in a copying machine, a filter that cuts red light is required.
There are disadvantages in the copy machine design.

The photoreceptor using a distyrylbenzene-based disazo compound and a hydrazone compound as shown in (3) is very advantageous in terms of manufacturing because it can easily form a charge-generating layer by applying a dispersion of the disazo compound. , Similar to the photoconductor (2), its photosensitive wavelength range is approximately 450 to 70'' On
Since the length of the red original is over 100 m, it has the disadvantage that image reproduction of red originals is poor.

In view of the above-mentioned drawbacks, the inventors of the present invention set out to develop a laminated photoreceptor that can be easily manufactured and whose photosensitive wavelength range is in the short wavelength region (that is, has excellent image reproducibility for red originals). As a result of intensive studies regarding the purpose, we found that a certain disazo compound was used as a charge generator (^) to generate a
Laminated type sensitive body made up of 7 curses - achieved the purpose of 5
The present invention was completed based on the knowledge that

That is, the electrophotographic photoreceptor of the present invention is a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, wherein the charge generation layer has the general formula (I) and the margin below (formula (wherein, X represents a substituted or unsubstituted aromatic ring or heterocycle, and Ar represents a substituted or unsubstituted aromatic ring or heterocycle C). It is characterized by Specific examples of the aromatic ring in X of general formula (1) include a benzene field and a naphthalene term, and examples of the decyl group of -ttJ9 include an indole ring, a carbazole ring, and a benzofuran ring. Specific examples of the aromatic ring in Ar include benzene U to naphcrene, and specific examples of the betero ring include di-4-zofuran ring, carbazole ring, and the like.

Examples of the above-mentioned substituents include a lower alkyl group, a lower alkoxyl group, a dialkylamino group, a halogen, a nitro group, a cyan group, a carxyl group or an ester thereof, a halomethyl group, a sulfone group, or a salt or ester thereof.

The laminated photoreceptor of the present invention is easy to manufacture, and has a photosensitive wavelength region of short wavelength region (450 to 600 nm).
), making it an excellent photoreceptor for copying machines.

The present invention will be described and explained in more detail below.

First, specific examples of the charge generating substance used in the charge generating layer in the present invention, that is, the disazo compound represented by the general formula (Il) are as follows.

Below are the blank spaces.
Φ chain of ~ size o O
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H1 Engineering Engineering Engineering Country Engineering E Country Masaru Ta Engineering Engineering Masaru Country Country 0N=N-A 隘 A A tetrazonium salt obtained by diazotizing a compound (prepared as Naphthol AS) by a conventional method and a corresponding coupler (naphthol AS) are combined by reacting with a base in a suitable organic solvent such as N,N-dimethylformamide (DMF). It can be easily produced by carrying out a ring reaction. As an example, a production example of the disazo compound of the above-mentioned ridges 1-13 is shown below, but other disazo compounds can also be easily produced according to this production example, except for changing the coupler.

Production Example 1.5 - Cyabanoanthraquinone 4.76 fr to 36
% hydrochloric acid was added and the mixture was cooled to about θ°C. Add 3.0g of 97% sodium nitrate to 1 part of water.
The solution was added dropwise over a period of about 15 minutes at 0-5°C. After completion of the dropwise addition, the reaction mixture was stirred for an additional 30 minutes at about θ°C, and then filtered to remove some insoluble matter. Then, approximately xomt of F solution Vc42% HBF4 was added, and the precipitate that had separated out was separated and washed with methanol. The obtained crystals were dried under reduced pressure to obtain light brown anthraquinone-1,5-bisdiazonium pistetrafluorozelate 8.461r.

Infrared absorption spectrum (KBr tablet method) νNP2300
Cm - vCo 1695 crn - Tetrazonium salt obtained as above 2.18trh
Yohi 2-hydroxy-3-phenylcaltumamoylnaphthalene (naphthol As) 2.63 #r in DMF 300
A solution of 1.64 JFr of sodium acetate dissolved in 44 ml of water was added dropwise thereto at room temperature (about 20° C.) for about 5 minutes. After the addition was completed, the mixture was stirred at the same temperature for an additional 2 hours, and then the precipitated crystals were collected. Next, 300 m/m of DMF was added to the crystals, and the mixture was stirred at 80°C for 2 hours, and then the crystals were separated again, and this operation was repeated twice. Thereafter, the crystals were washed with water and dried at 80° C. under reduced pressure.

2.71 lIr (69.0%) of disazo compound J% 1-13 was obtained as a red powder.

Melting point -300°C or higher Elemental analysis result Actual value Calculated value C% 73.57 73.27H% 3.
82 3.85 N% 10.4:2 10.68 Infrared absorption spectrum (KBr tablet method) νNH (secondary amide)
325ottn-'νc0 1675C
1n-1 The main feature of the present invention is to use a disazo compound represented by the above general formula (1) as the charge-generating substance in the charge-generating layer. Substances are particularly sensitive to temperature, but typical examples are as follows.

(1) Hydrazone compound attenuated by general formula (II) [
In the formula, %R1 represents a methyl group, an ethyl group, a sz-hydroxyethyl group, or a 2-chloroethyl group, R1 represents a methyl group, an ethyl group, a benzyl group, or a phenyl group, and R3
is hydrogen.

Chlorine, bromine, alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms
represents an aralkyl group, dialkylamino group or nitro group. ] (2) Hydrazone compound 1 represented by general formula (e) (wherein, A'&'? naphthalene ring, anthracene ring, styryl group and their substituted products, or pyridine ring, furanate ring, 1,000-offene ring) Generally, R represents an argyl group or a benzyl group having 1 to 4 carbon atoms.] (3) A hydrazone compound represented by the general formula IV) [wherein, R1*R1e R3@Ej4 is hydrogen, C1
-3 alkyl group, C1-3 alkoxy group, dialkylamino group or dibenzylamino group s R
8 represents an alkyl group or benzyl group having 1 to 4 carbon atoms,
1) Yes. ] (4) Hydrazone compound represented by general formula (v) [wherein hR1eR mushroom, R3 and ■14 are hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, substituted or unsubstituted Represents a dialkylamino group, dibenzylamino group or halogen atom. (5) Diarylmethane compound C represented by the general formula (VJ) In the formula, R1 is an argyl group having 1 to 11 carbon atoms.

Represents a substituted or unsubstituted phenyl group or a heterocyclic group, R*e R3 may be the same or different, and hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloralkyl group, Represents a substituted or unsubstituted aralkyl group, and R2 and R3 may be bonded to each other to form a nitrogen-containing heterocycle 64 R44R5 may be the same or different, hydrogen, carbon number 1 to 4
represents an alkyl group, an alkoxy group, or a halogen. ]
(6) An anthracene compound represented by the general formula MO [wherein, meat represents hydrogen or a halogen atom].

R2t? Hydrogen-' represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group, or a substituted or unsubstituted dialkylamino group, and R3 is hydrogen or an argyl group having 1 to 4 carbon atoms. Or represents a halogen atom. ] (7) Fluorene, a compound represented by the general formula (■) [
In the formula, R1 is hydrogen, halogen, s(r) group, and has 1 to 4 carbon atoms.
represents an alkoxy group or an alkyl group having 1 to 4 carbon atoms, Ar is 4 6 R1e R8e R1+ is hydrogen, it is 1 to 4 carbon atoms
*R4*R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted benzyl group.

represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group. ] (8) Divinylbenzene compound achieved by the general formula! Proboscis [wherein R is a carbazolyl group or a pyridyl group.

a chenyl group, an indolyl group, a furyl group, or a substituted or unsubstituted phenyl group, a styryl group, a naphthyl group or an anthryl group, and these substituents are a dilykylamino group, an alkyl group having a carbon number of 1 to 4; group, carbon number 1
-4 alkoxy groups, . . . represent a group selected from the group consisting of a rogen atom, an aralkylamino group, an N-'γlkyl-N-aralkyl amino group, and an amino group. ] (9) Pyrazoline compound represented by the general formula [wherein,
R1v and R3 are hydrogen, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms.

It represents a sialgylamine group or a halogen atom, and n represents 0 or 1. ] Specific examples of the above charge transport materials are as follows.

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CHs CH3 In addition to the above-mentioned exemplified compounds, for polymeric substances, l IJ-N
-Vinylcartumasol, halogenated-poly-N-vinylcarbazole, polyvinylpyrene.

Or brompyrene-formaldehyde condensation resin, N
Condensation resins such as -ethylcarbazole-formaldehyde condensation resins, and low-molecular substances such as oxazole derivatives, oxadiazole derivatives, and nitro derivatives of fluorenone are all effective.

FIG. 1 is an enlarged sectional view of an electrophotographic photoreceptor showing an embodiment of the present invention. This photoreceptor is constructed such that a charge generation layer 22 and a charge transport layer 33 are provided on a conductive support 11 to form a photosensitive layer 44 .

The conductive support used in the present invention includes:

Metal plates made of aluminum, nickel, chromium, etc.
metal drum or metal foil, and aluminum, tin oxide,
A plastic film provided with a thin layer of indium oxide, chromium, radium, etc., and paper or plastic film coated with or impregnated with a conductive substance are used.

The charge generation layer is a liquid in which a specific disazo compound represented by the general formula (■) shown above is made into fine particles by a means such as a Zeel mill, and dispersed in a suitable solvent, or if necessary, a binder resin is added to this. (a) A dispersion in which is dissolved is coated on a conductive support, and if necessary, the surface is finished by, for example, a method such as puff polishing, and the film thickness is adjusted.

The thickness of the lightning-generating layer is preferably 0.01 to 5 μm,
<005 to 2 μm and dust, the proportion of the disazo compound in the charge generation layer is 10 to 100%, preferably 30 to 9
5 double injection%. The thickness of the charge generation layer is O,'01μga1
If the diameter is less than 5 μm, the sensitivity is poor, and if the diameter is 5 μm or more, the potential cannot be maintained. Furthermore, if the proportion of the disazo pigment in the charge generation layer is less than 10, the sensitivity is poor.

The charge transport layer is formed by applying 7 g of a solution prepared by dissolving the various charge transport layer materials described above and a binder resin in a suitable solvent such as tetrahydrofuran onto the charge generating layer. Here, the proportion of the charge transport substance contained in the charge transport layer is 10 to 80% by weight, preferably 25 to 75% by weight, and the film thickness is 2 to 100 μm, preferably 5 to 80% by weight.
It is 40 μm. If the proportion of the charge transport substance contained in the charge transport layer is less than 10% by weight, the sensitivity will be poor, and if it is more than 80% by weight, the film will become brittle or crystals will precipitate and the charge transport layer will become cloudy, which is not preferable. Further, if the thickness of the charge transport layer is 5 μm or less, the potential is not maintained well, and if the thickness is 40 μm or more, the residual potential becomes high.

The binder resin for the charge generating j- used here includes polyester resin, butyral resin, ethyl cellulose resin, epoxy resin, acrylic resin, vinylidene chloride resin, polystyrene, s5 IJ butadiene, and copolymers thereof. These can be used alone or in a mixed state of two or more.

Further, as the binder resin for the charge transport layer, polycarbonate resin, polyester resin, Bolistima/7. Examples include polyurethane resins, epoxy resins, acrylic resins, silicone resins, and copolymers thereof, and these may be used alone or in a mixed state of two or more.

Furthermore, various additives can be added to the charge transport layer for the purpose of improving flexibility or durability. Examples of additives used for this purpose include non-logenated paraffin, dialkyl phthalate, and silicone oil. It is also possible to provide an intermediate layer between the barrier layer, the charge generation layer and the charge transport layer, or an automatic coating layer on the charge transport layer.

Further, the disazo compound of the general formula (■) according to the present invention can be dispersed as fine particles in a binder resin (if necessary, a charge transport substance may be added) to form a dispersed photoreceptor. It can also be used as

The structure of the present invention is as described above, and as is clear from the examples described later, the electrophotographic photoreceptor of water valve 1 (j4) is easy to manufacture and has stable characteristics even when the photoreceptor is repeatedly used. It has some excellent properties.

Next, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited thereby.

Example 1 76 parts by weight of disazo compound number 1-1, d? Tetrahydrofuran solution (solid content concentration 2%) of polyester resin 200 (manufactured by Toyobo Co., Ltd.) 1260 heavy needles,
and 3,700 parts by weight of tetofhydrofuran were pulverized and mixed in a Zeel mill, and the resulting dispersion was applied onto the aluminum surface of an aluminum-deposited polyester 4-base (conductive support) using a doctor blade, and air-dried. A charge generation layer having a thickness of about 1 μm was formed.

- 2 parts by weight of it carrier substance $2-327, -
After mixing and dissolving 2 parts by weight of polycarbonate resin (Teijin Co., Ltd. #1300° in Panlite) and 16 parts by weight of tetrahydrofuran to form a solution, this was applied onto the charge generation layer with a doctor blade at 80'C; Dry for 2 minutes at 00℃ for 5 minutes at 1.00℃ to a thickness of approximately 2071 tons.
A charge transfer layer of n was formed, and a laminated type structure 1 shown in FIG. 1 was prepared.

Examples 2 to 19 Same as Example 1 except that the disazo compound and charge transport substance shown in Table 1 below were used instead of the disazo compound 1-1 and charge transport substance 1412-327 used in Example 1. Photoreceptor gaps 2 to 19 were prepared in the same manner.

These photoconductor groups 1 to 19 were negatively charged by performing corona discharge of -6 KV for 20 seconds using a static M1 copying paper testing device (manufactured by Kawaguchi Denzoku Seisakusho Co., Ltd., model SP 428). , leave it in the dark for 20 seconds, set the surface potential Vpo (V) at 1lll+, and then illuminate the surface with a tungsten lamp at an illuminance of 20 lux (Z)
After irradiating light, the time (seconds) until the surface potential reaches % of Vpo is determined, and the amount of light E3A, (lux/
seconds) was calculated.

The results are shown in Table-1.

Furthermore, in order to examine the durability of the photoreceptor of the present invention against repeated use, the photoreceptor weight 6 of the present invention was attached to a copying machine Ricoh-P-500 manufactured by Ricoh Co., Ltd., and an image was output using io.
Repeated ooo times.

As a result, a clear image was obtained even after 10,000 repetitions. From this, it can be understood that the photoreceptor of the present invention has extremely excellent durability.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention.

Claims (1)

[Scope of Claims] 1. In a laminated electrophotographic photoreceptor having a charge generation layer and a charge transport layer on a conductive support, the charge generation layer has the general formula (I) (wherein, X is An electrophotographic photoreceptor comprising a layer containing a disazo compound represented by a substituted or unsubstituted aromatic ring or heterocycle, and Ar represents a substituted or unsubstituted aromatic ring or heterocycle. .