JPS59214035A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity, easy to manufacture, and suitable for repeated uses by forming a photosensitive layer contg. a specified disazo pigment as an effective component on a conductive substrate. CONSTITUTION:An intended electrophotographic sensitive body is obtained by forming on a conductive substrate, such as an aluminum plate, a photosensitive layer contg., as an effective component, a disazo pigment represented by formula I in which R<1>, R<2> are H, lower akyl, aralkyl, aromatic, or heterocyclic, and both may form a ring together with each other. Said pigment can be easily prepared by using 2-hydroxy-naphthoic acid hydrazides as a starting material. The electrophotographic sensitive body of this invention may be a single layer type contg. said pigment, but it is preferable to form a double layer type composed of an electrostatic charge generating layer contg. a disazo compd. of formula I and a charge transfer layer contg. a charge transfer material, such as formula II or III.

Description

[Detailed description of the invention] Technical field The present invention relates to a photoreceptor for electrophotography.

PRIOR ART Photoconductors for electrophotography include inorganic photoconductors, such as those using selenium and its alloys, or photoconductors with dye-sensitized zinc oxide dispersed in a binder resin, and organic photoconductors. For example, 2.4. ? -) One using a charge transfer complex of Lietro 9-fluorenone (TNF) and poly-N-vinylcarno-9zole (PVK) is known as a representative example.

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

For example, the currently widely used selenium photoreceptor has difficult manufacturing conditions, high manufacturing costs, and is difficult to process into a belt shape due to its lack of flexibility.
It is also sensitive to heat and mechanical shock, so it requires a large amount of injection when handling.

Zinc oxide photoreceptors are low in cost because they can be manufactured by applying inexpensive zinc oxide to a support, but they generally have low sensitivity and poor surface smoothness, hardness, tensile strength, and abrasion resistance. It has mechanical drawbacks, and as a photoreceptor for plain paper copying machines, which is normally used repeatedly, there are many problems with durability.

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 to eliminate the drawbacks of these photoreceptors, and in particular, various organic photoreceptors have been proposed. Among these, there is a layer containing a substance C (hereinafter referred to as "charge generation material") that generates charge carriers when irradiated with light (hereinafter referred to as "charge generation layer"), and a layer that receives and receives the generated charge carriers. A laminated photoreceptor consisting of a layer (hereinafter referred to as a "charge transport layer") mainly containing a transporting substance (hereinafter referred to as a "charge transporting material") generally has higher sensitivity than conventional organic photoreceptors. Due to its stable charging properties, it has attracted attention as a photoreceptor for plain paper copying machines, and some 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 amine solution of chlordian blue as the charge generation layer and a hydrazone compound used as the charge transport layer (Japanese Patent Publication No. 155-423
(see Publication No. 80) and the like are known.

However, although conventional photoreceptors of this type have many advantages, they also have various drawbacks as described below.

The photoreceptor using the perylene derivative and oxadiazole derivative shown in (1) above has a high manufacturing cost because its charge generation layer is formed by vacuum deposition.

A photoreceptor using chlordian blue and a hydrazone compound as shown in (2) above uses an organic amine (which is generally difficult to handle) as a coating solvent for forming a charge generation layer.
For example, it is necessary to use ethylene cyakine), which has disadvantages in producing a photoreceptor.

Purpose The present invention provides an electrophotographic photoreceptor that can be manufactured easily and is suitable for repeated use.

Structure The electrophotographic photoreceptor of the present invention is prepared by disposing a compound of the following general formula (5-) on a conductive support (wherein and R2 are hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic group,
Represents a substituted or unsubstituted heterocyclic group. R1 and R1 may be the same or different, and 11,
Rt may jointly form a ring. ) A photoconductive layer (photosensitive layer) containing a disazo compound represented by the following formula is provided.

Here, as the lower alkyl group in the general formula (D,
Methyl group, ethyl group, prozyl group, etc., aralkyl group such as benzyl group, phenethyl group, etc., aromatic group such as phenyl group, naphthyl group, anthryl group, pyrenyl group, anthraquinonyl group, etc. Examples of the heterocyclic group include a chenyl group, a furyl group, a pyridyl group, a carnozolyl group, and R1 and R
Examples of the ring formed by 2 include a hexylidene ring, a pentylidene ring, a penzylidene ring, a dibenzopentylidene ring, and the like. Examples of the aralkyl group, aromatic group, heterocyclic group, or disubstituted group in the ring formed by R1 and R2 include a lower alkyl group, a lower alkoxy group, a halogen atom, a cyano group, a nitro group, a lower dialkylamino group, etc. can.

Incidentally, the present invention is based on the inventor's extensive studies to achieve the above-mentioned object, and the discovery that the use of a specific disazo pigment (disazo compound) is extremely useful for electrophotographic photoreceptors. This was done based on the following. Furthermore, the electrophotographic photoreceptor of the present invention is not limited to a single-layer type, but rather is preferably a laminated type in which the photosensitive layer is composed of a charge generation layer and a charge transport layer. In such a laminated electrophotographic photoreceptor, the charge generation layer is formed of a layer containing a disazo pigment represented by the general formula (I).

The present invention will be described in more detail below. First, specific examples of the disazo compound represented by the general formula (I) used in the present invention are as follows.

These disazo compounds are prepared by combining the diazonium salt described in JP-A No. 55-69654 and the corresponding coupler (2-hydroyacyl-3-naphthoic acid hydrazide) in an appropriate organic solvent such as N , N
- It can be easily produced by reacting with a base in dimethylformamide (DMF) to cause a coupling reaction.

By the way, as described earlier, the photoreceptor of the present invention is
The charge-generating substance represented by the general formula (I) is contained in the photosensitive layer, but in an actual photoreceptor, the charge-generating substance and the charge-transporting substance are combined to form the photosensitive layer (photoconductive layer). layer) is formed.

Although the charge transporting substance used in the present invention is not specified, typical examples thereof are as follows.

[Rlo is an alkyl group such as a methyl group or an ethyl group, 12
- Substituted alkyl group such as 2-chloroethyl group or 2-hydroxyethyl group, R11 is an alkyl group such as methyl group or ethyl group, aralkyl group such as benzyl group, or aryl group such as phenyl group Rlm is a hydrogen atom, chlorine, or bromine represents a halogen atom such as, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a dialkyl group, or a nitro group. ] (Ar' represents a naphthyl group, an anthryl group, a styryl group, or a substituent thereof; 111 represents an alkyl group such as a methyl group or an ethyl group; an aralkyl group such as a benzyl group; or an aryl group such as a phenyl group; a naphthyl group; Examples of substituents on anthryl and styryl groups include alkyl groups such as methyl and ethyl groups, alkoxy groups such as meth-13-oxy and ethoxy groups, and dialkylamino groups such as dimethylamino and diethylamino groups. [R14, R11 or R1 is a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, or a propyl group, an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group, a halogen atom such as chlorine or bromine, or a nitro group. or represents a hydroxyl group, and R1' is a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, or a propyl group, an alkoxy group such as a methoxy group, an ethoxy group, or a propoxy group, a dialkylamino group such as a dimethylamino group or a diethylamino group, or a dialkylamino group such as a dimethylamino group or a diethylamino group; dialkylamino groups such as benzylamino groups, dialkylamino groups such as diphenylamino groups, halogen atoms such as chlorine and bromine, nitro groups or hydroxyl groups, R11
represents an alkyl group such as a methyl group or an ethyl group, an aralkyl group such as a benzyl group, or an aryl group such as a phenyl group.] (Rle, RlG, Hll or R11 represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, etc.) Alkyl groups, alkoxy groups such as methoxy groups, ethoxy groups, and propoxy groups; dialkylamino groups such as dimethylamino groups and diethylamino groups; halogen atoms such as chlorine and bromine;
Represents a nitro group or a hydroxyl group. ] (Rlm is an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted heterocyclic group, R1
4 or R1 represents a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a chloro-substituted alkyl group, a hydroxy-substituted alkyl group, a substituted or unsubstituted aralkyl group, and R34 and Hll are mutually They may be combined to form a nitrogen-containing heterocycle.

HH or R17 represents a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a furoyl group, a butyl group, an alkoxy group such as a methoxy group or an ethoxy group, or a halogen atom such as chlorine or bromine. Examples of the heterocyclic group for R18 include pyridyl group, furyl group, chenyl group, indolyl group, pyrrolyl group,
Examples include quinolyl group and carnozolyl group.

Examples of the substituent on the phenyl group or heterocyclic group of R■ include alkyl groups such as methyl group and ethyl group, and alkoxy groups such as methoxy group and ethoxy group. Examples of the aralkyl group of Hffi4 or R1 include a benzyl group, and substituents on the aralkyl group include chlorine, halogen atoms such as -X, alkyl groups such as methyl and ethyl groups, and nitro groups. I can give an example. A morpholine ring is an example of the heterocycle formed by bonding R1& and R211 to each other. ] (R18 is a hydrogen atom, a halogen atom such as chlorine or bromine,
RHI is a hydrogen atom, a halogen atom such as chlorine or bromine, an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, or a dialkylamino group such as a dimethylamino group, a diethylamino group, or a dibutylamino group. , a dialkylamino group such as a dibenzylamino group or a chloro-substituted diethylamino group, a halogen atom such as a nitro group, a cyano group, or 17-mono group, or an alkyl nor such as a methyl group or an ethyl group. ] [Ra1 is a hydrogen atom, chlorine, bromine, etc.), a rhodane atom, an alkyl group such as a methyl group, an ethyl group, a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a butoxy group, or a cyano group, R11l or R1 is Hydrogen atom, alkyl group such as methyl group, ethyl group, butyl group, substituted alkyl group such as 2-chloroethyl group, 2-hydroxyethyl group, substituted or unsubstituted benzyl group,
R or R111 is a hydrogen atom, a halogen atom such as chlorine or bromine, an alkyl group such as a methyl group, an ethyl group or a butyl group, an alkoxy group such as a methoxy group, an ethoxy group or a butoxy group, a diethylamino group, a diethylamino group, etc. Examples of the substituent for the benzyl group Kk of s R''t or Rll representing a dialkylamino group include an alkyl group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, and a nitro group. ] (A/ represents an N-alkylcarbazolyl group, and examples of the alkyl group include a methyl group, ethyl group, propyl group, butyl group, etc.) (Bj・, Ra?, R11
8 is a hydrogen atom, a halogen atom such as chlorine or bromine, an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, a nitro group or an alkyl group B8
″ is a hydrogen atom, a halogen atom such as chlorine or bromine, an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as meth, an oxy group, an ethoxy group, a dimethylamino group, a diethylamino group, a dibutylamino group, etc. Substituted or unsubstituted dialkylamino groups such as dialkylamino groups, dibenzylamino groups, chloro-substituted dibenzylamino groups, methyl-substituted dibenzylamino groups, methoxy-substituted dibenzylamino groups, N-methyl-N-benzylamino groups, etc. [Ra4 is an N-alkylcarbazolyl group, Represents a pyridyl group, chenyl group, indolyl group, furyl group, or a substituted or unsubstituted naphthyl group, styryl group, or anthryl group.Substituents in the naphthyl group, styryl group, and anthryl group include a methyl group and an ethyl group. Examples include alkyl groups such as methoxy groups, alkoxy groups such as ethoxy groups, dialkyl groups such as dimethylamino groups and diethylamino groups.] CR41, 84m is a hydrogen atom, a methyl group, an ethyl group,
Alkyl groups such as thyl groups, methoxy groups, ethoxy groups,
It represents an alkoxy group such as a butoxy group, a halogen atom such as chlorine or bromine, or a dialkylamino group such as a dimethylamino group or a diethylamino group, and % nl represents 0 or 1. ] (Ra41, R44 are hydrogen atoms, methyl groups,
Alkyl groups such as ethyl groups, alkoxy groups such as methoxy groups and ethoxy groups, I-rodane atoms such as chlorine, 21-R41, R4m are methyl groups, ethyl groups, propyl groups,
Alkyl group such as butyl group, substituted or unsubstituted aralkyl group, substituted or unsubstituted aryl group, R4? represents a hydrogen atom or a substituted or unsubstituted phenyl group.

An example of the aralkyl group of H41,R4. is a benzyl group, and an example of the aryl group is a phenyl group. Substituents on aralkyl or aryl groups include alkyl groups such as methyl, ethyl and butyl groups, alkoxy groups such as methoxy and ethoxy groups, I-rodane atoms such as chlorine, diethylamino groups and diethylamino groups. An example is a dialkylamino group. ] (R411 and H49 represent an alkyl group such as a methyl group or an ethyl group, a substituted or unsubstituted 7-ale group, or a substituted or unsubstituted benzyl group. Examples of the substituent include an alkyl group such as a methyl group or a square group. Examples include alkoxy groups such as , methoxy group, and ethoxy group.] (RIIO and R111 represent the same groups as the above R''@TL' wound.) (BI1 represents a hydrogen atom, an alkyl group such as a methyl group, and an ethyl group, substituted or unsubstituted phenyl group,
A represents an integer of 0 or 1, and A represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group. Here, R111 is a hydrogen atom, an alkyl group, a 12-substituted amino group (R14
, BI3 represents an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a substituted or unsubstituted aralkyl group such as a benzyl group, a substituted or unsubstituted aryl group such as a phenyl group, and BI4 f? and R1
A ring may be formed with 1 liter. ), where m is 0, 1 .
Represents an integer of 2 or 3, and when m is 2 or more, 88m
may be the same group or different groups. -4 or R”K
Examples of substituents on the aralkyl or aryl group include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy and ethoxy; , dialkylamino groups such as dimethylamino group and diethylamino group. ] Further, specific examples of these charge transport substances are as follows.

24- Compound A Structural Formula % Formula % (Compound Structural Formula CvH4c
L C禦H, 0H C8山OH 26- Compound store Structure Shiaimoni
Structural formula-16 CH.

28- 29- Compound point structure ° formula hardware shop
Structural formula 32- Compound point Structural formula compound
Structural Formula 2-44 Compound Grave Structural Formula Compound Product
Structural Formula -52 -53 37- Compound Structure Formula 2-54 -55 -56 -57 Compound & Structural Formula In addition to the above-mentioned exemplified compounds, polymer substances include poly-N-vinylcarbazole, halogenated - Condensation resins such as poly N-vinylcarbazole, polyvinylpyrene, bromopyrene-formaldehyde condensation ff1M resin, N-ethylcarbazole-formaldehyde condensation resin, and low molecular weight substances such as oxazole derivatives, oxadiazole 8 conductors, and fluorenone. Any of the known electrifying substances such as nitro derivatives are effective.

The attached drawings are representative enlarged sectional views of two sides of the electrophotographic photoreceptor to be tested according to the present invention, and FIG.
A photosensitive layer 41, which is a partial layer containing a charge generating substance 21 and a charge transporting substance 31, is provided thereon, and FIG. 2 shows a multilayer structure in which a charge generating layer 22 and a charge transporting layer 32 are provided on a conductive support 11. The photosensitive layer 42 shown in FIG. Compared to the former, the latter laminated type electrophotographic photoreceptor (shown in Figure 2) is more advantageous in various aspects. Note that the photosensitive layer can also be formed by dispersing a disazo compound represented by the general formula (1) in a binder resin, without using the above-mentioned charge transporting substance.

The conductive support 11 used in the present invention is a metal plate, metal drum, or metal foil made of aluminum, nickel, chromium, etc., and a thin layer of plastic made of aluminum, tin oxide, indium oxide, chromium, palladium, etc. Paper or plastic film coated with or impregnated with a conductive substance is used.

In the laminated type photoreceptor, the charge generation layer 22 is made of a solution in which a specific disazo compound represented by the general formula (1) shown above is made into fine particles by a means such as a Zeel mill, neutralized and dispersed in an appropriate solvent, or as necessary. A dispersion in which a binder resin is dissolved in this is applied and formed on the conductive support 11, and if necessary, the surface is finished by a method such as puff polishing, and the film thickness is adjusted. It is something.

The thickness of the charge generation layer 22 is 0.01 to 5 μm, preferably 0.05 to 2 μm, and the proportion of the disazo compound in the charge generation layer 22 is 10 to 100% by weight, preferably 30 to 95% by weight. It is.

If the thickness of the charge generation layer 22 is 0.01 μm or less, sensitivity is poor, and if it is 5 μm or more, potential retention is poor.

Further, if the proportion of the disazo pigment in the charge generation layer 22 is less than 10 times 1 teIb, the sensitivity is poor.

The charge transport layer 32 is formed by coating the charge generation layer 22 with a solution in which the various charge transport substances and binder resin described above are dissolved in a suitable solvent such as tetrahydrofuran. Here, the proportion of the charge transport substance contained in the charge transport layer 32 is 10 to 80% by weight, preferably 25% by weight.
~75% by weight and 1. The film thickness is 2 to 100 μm, preferably 5 to 40 μm. If the proportion of the charge transport substance contained in the charge transport layer 32 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 32 will become cloudy, which is not preferable. Furthermore, if the thickness of the charge transport layer 32 is 2 μm or less, the potential is not maintained well (,
If the thickness is 100 μm or more, the residual potential becomes high.

Examples of the binder resin for the charge generation layer 22 used here include polyester resin, butyral resin, ethyl cellulose resin, epoxy resin, acrylic resin, vinylidene chloride resin, polystyrene, polybutadiene, and copolymers thereof. , they may be used alone or in a mixed state of two or more.

Examples of the binder resin for the charge transport layer 32 include polycarbonate resin, polyester resin, polystyrene, polyurethane/resin, epoxy resin, acrylic resin, silicone resin, and copolymers thereof. It can be used as a species or in a mixture of two or more types.

Furthermore, various additives can be added to the charge transport layer 32 for the purpose of improving flexibility or durability. Additives used for this purpose include halogenated paraffins, dialkyl phthalates, silicone oils, and the like.

Furthermore, in the photoreceptor of the present invention, a barrier layer is provided between the conductive support 11 and the charge generation layer 22, an intermediate layer is provided between the charge generation layer 22 and the charge transport layer 32, and the charge transport layer 32 is provided as necessary. An overcoat layer can also be provided thereon.

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

Example 1 A solution of 76 parts by weight of disazo compound A I-32 and polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) in tetrahydrofuran (solid content concentration 2 m) 126
0 parts by weight and 3,700 parts by weight of tetrahydrofuran were pulverized and mixed in a 2-luminium mill, and the resulting dispersion was applied onto the A/I/1 side of an aluminum-deposited polyester base (conductive support) using a doctor blade. It was coated and air-dried to form a charge generation layer with a thickness of about 1 μm. On the other hand, 2 parts by weight of charge transport substance 42-29, polycarbonate resin (Pan 2ite K 130G, manufactured by Banjin Co., Ltd.)
After mixing and dissolving 2 parts by weight and 16 parts by weight of tetrahydrofuran to form a solution, this was applied onto the charge generation layer using a doctor blade, and then heated at 80°C for 2 minutes and then at 100°C.
The mixture was dried for 5 minutes to form a charge transport layer with a thickness of about 20 μm, thereby producing a laminated photoreceptor A1 shown in FIG.

Examples 2 to 10 Example 1 except that the disazo compound and charge transport substance shown in Table 1 below were used in place of the disazo compound AI-32 and charge transport substance 2-29 used in Example 1.
Photoreceptors A2 to A10 were prepared in the same manner as above.

These photoreceptors 1 to IOK were negatively charged by performing -6 KV =rona discharge for 20 seconds using an electrostatic copying paper testing device (%' sp 428 type manufactured by Kawaguchi Electric Seisakusho Co., Ltd.). After that, the sample was left in a dark place for 20 seconds, and the surface potential Vpo (V) at that time was measured. Then, the surface was irradiated with light using a tungsten lamp at an illuminance of 45-4.5 lux, and the surface potential was measured. The time (seconds) until Vpo reached H was determined, and the amount of fog light E% (Ntx·sec) was calculated. Table the results.
Shown in 1.

Table 1 In addition, the photoconductor plate 1 of the present invention was mounted on a copying machine Ricopy P-500 manufactured by Ricoh Co., Ltd., and image production was repeated 10,000 times. As a result, a clear image was obtained even after 10,000 repetitions.

From this fact, it can be understood that the photoreceptor of the present invention is also excellent in durability.

Effects As described above, the electrophotographic photoreceptor of the present invention is easy to manufacture and has excellent properties such as stable characteristics even after repeated use of the photoreceptor.

[Brief explanation of drawings]

1 and 2 are enlarged sectional views showing two typical sides of the electrophotographic photoreceptor of the present invention.

Claims (1)

[Claims] 1. The following general formula (1) (in the formula R1
and R3 is hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic group, or
Substituted or unsubstituted heterocyclic group. Here, R1 and R1 may be the same or different, or
R1 and R1 may jointly form a ring. ) An electrophotographic photoreceptor comprising a photosensitive layer containing a disazo pigment represented by the following formula as an active ingredient.