JPS59218449A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance stability of a photosensitive body by forming a photosensitive layer contg. a specified disazo pigment as an effective component on a conductive supporting material. CONSTITUTION:A photosensitive layer formed on a conductive supporting material contains as an effective component a disazo compd. represented by the formula shown here in which R<1>, R<2> are each H, lower alkyl, such as methyl, aralkyl, such as benzyl, aromatic, such as phenyl, or heterocyclic, such as thienyl, and a ring formed from R<1> and R<2> is embodied by a hexylidene ring, etc. A combination of an electrostatic charge generating substance represented by the formula and a charge transfer substance is contained in the photosensitive (photoconductive) layer to form an electrophotographic sensitive body. This charge geerating layer has 0.05-2mum thickness and a preferable content of said pigment in this layer is 30-95wt%. Said electrophotographic sensitive body can be easily manufactured and its characteristics is stable even against repeated uses of it.

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, 2,4,7-dolinitro-9-fluorenone (TNF) and poIJ-N
A typical example is one using a charge transfer complex with -vinylcarbazole (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, 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 care must be taken when handling it.

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 (hereinafter referred to as "charge generation medium") containing a substance that generates charge carriers when irradiated with light (hereinafter referred to as "charge generation medium"), and a layer in which the charge generation layer receives the generated charge carriers. Compared to conventional organic photoreceptors, a laminated photoreceptor consisting of a substance that transports this (hereinafter referred to as "charge transport material" 5) and PFA (hereinafter referred to as "charge transport layer") mainly composed of Y Generally, it has attracted attention as a photoreceptor for plain paper copying machines because of its high sensitivity and stable charging properties, and some of them are in practical use.

This type of conventional laminated photoreceptor uses 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 Chlordiane Blue as the charge generation layer and a hydrazone compound used as the charge transport layer (% Kosho 55-42
380), etc. 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 described above has a high manufacturing cost because its charge generation layer is formed by vacuum deposition.

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

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

Structure The electrophotographic photoreceptor of the present invention is formed by forming a compound of the following general formula (RI) on a conductive support (where Hl and Hz 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.11 and R''
& may be the same or different, and those R'
, R'' may jointly form a ring.) A photoconductive layer containing a disazo compound (photosensitive N
) is a feature.

Here, the lower alkyl group in general formula (1) includes a methyl group, an ethyl group, a propyl group, etc., the aralkyl group includes a benzyl group, a 7enethyl group, etc., and the aromatic group includes a phenyl group, a naphthyl group, Examples of heterocyclic groups include anthryl group, pyrenyl group, and anthraquinonyl group; examples of heterocyclic groups include chenyl group, furyl group, pyridyl group, and carbazolyl group; and examples of the ring formed by R1 and Rx include hexylidene ring, pentylidene ring, and benzopentyl group. Examples include a lydene ring and a dipenzopentylidene ring. Examples of substituents on the aralkyl group, aromatic group, heterocyclic group, or the ring formed by R1 and R1 include a lower alkyl group, a lower alkoxy group, a halogen atom, and a cyan group.

Examples include a nitro group and a lower dialkylamino group.

Incidentally, the present invention is based on the following: As a result of extensive studies in order to achieve the above object, the present inventor discovered that the use of a specific disazo pigment (disazo compound) is extremely useful for electrophotographic photoreceptors, and This was done based on the following. Also.

The electrophotographic photoreceptor of the present invention is not limited to a single-layer type, but is preferably a laminated type in which the photosensitive layer is separated from the charge generation layer and the 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 (1).

The present invention will be explained in more detail below.

First, specific examples of the disazo compound represented by the general formula (1) used in the present invention are as follows.

These disazo compounds are the diazonium salts described in JP-A-54-12742.

The corresponding coupler (2-hydroxy-3-naphthoic acid hydrazide) is dissolved in a suitable organic solvent such as N,
It can be easily produced by reacting with a base in N-dimethylformamide (DMF) to cause a coupling reaction.

By the way, as described earlier, one photoreceptor of the present invention is
The charge generating substance represented by the general formula (1) is contained in the photosensitive layer at an intermediate pressure, but in an actual photoconductor, the charge generating substance and the charge transporting substance are combined to form the photosensitive layer (photoconductive layer). ) is formed.

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

(alG is an alkyl group such as a methyl group or an ethyl group,
-substituted alkyl group such as chloroethyl group or 2-hydroxyethyl group; RlK is a methyl group;

Alkyl groups such as ethyl groups, aralkyl groups such as benzyl groups, aryl groups such as phenyl groups, 11m is a hydrogen atom, a halogen atom such as chlorine or bromine, a methyl group, an ethyl group, or a propyl group.

Alkyl groups such as butyl groups, methoxy groups, ethoxy groups,
It represents a propoxy group, a flukoxy group such as a butoxy group, a dialkylamino group, or a nitro group. ] (Ar' is a heptyl group, anthryl group, styryl group, or a substituted product thereof; Rlm is a methyl group.

It represents an alkyl group such as an ethyl group, an aralkyl group such as a benzyl group, and an aryl group such as a phenyl group. Examples of substituents on naphthyl, antri/l/, and styryl groups include alkyl groups such as methyl and ethyl groups, alkoxy groups such as methoxy and ethoxy groups, and dialkylamino groups such as dimethylamino and diethylamino groups. Examples include. ] (R14, RlB or R1'
F 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, or a halogen atom such as chlorine or bromine.

R16 represents a nitro group or a hydroxyl group, and R16 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 methquine group, an ethoxy group, or a propoxy group, a dialkylamino group such as a dimethylamino group or a diethylamino group, A dialkylamino group such as a dibenzylamino group, a diarylamino group such as a diarylamino group, a halogen atom such as chlorine or bromine, a nitro group or a hydroxyl group, R1' is an alkyl group such as a methyl group or an ethyl group, or a benzyl group represents an aralkyl group such as, or an aryl group such as phenyl group. ] [Blo H! O, R21 or R1! is a hydrogen atom, a methyl group.

Alkyl groups such as ethyl group and propyl group, methoxy group,
It represents an alkoxy group such as an ethoxy group or a propoxy group, a dialkylamino group such as a dimethylamino group or a diethylamino group, a halogen atom such as chlorine or bromine, a nitro group, or a hydroxyl group. ] Hall [R18 is an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted heterocyclic group, 1!
4 or Rls represents a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a zokyovir group, or a decyl group, a chloro-substituted alkyl group, a hydroxy-substituted alkyl group, or a substituted or unsubstituted aralkyl group, and R24 and R211 are They may be bonded to each other to form a nitrogen-containing heterocycle.

Hall or R1 is a hydrogen atom, a methyl group, an ethyl group,
Alkyl groups such as propyl and butyl groups, methoxy groups,
Represents an alkoxy group such as an ethoxy group, or a halogen atom such as chlorine or bromine. Examples of the heterocyclic group for R2s include a pyridyl group, a furyl group, a chenyl group, an indolyl group, a pyrrolyl group, a quinolyl group, and a carbazolyl group.

(!) Examples of substituents on the phenyl group or heterocyclic group in 8 include alkyl groups such as methyl A/ group and ethyl group, and alkoxy groups such as methoxy group and ethoxy group. Examples of the substituent in the group V (wherein V is aralkyl) include halogen atoms such as chlorine and bromine, alkyl groups such as methyl and ethyl groups, and nitro groups. A morpholine ring is an example of the heterocycle in which R14 and R1 are bonded to each other. ] [R1 is a hydrogen atom, a halogen atom such as chlorine, bromine,
12+1 is a hydrogen atom, a halogen atom such as chlorine, bromine,
Alkyl groups such as methyl group and ethyl group, alkoxy groups such as methoxy group and ethoxy group, dialkylamino group such as dimethylamino group, diethylamino group, diptylamino group, dibenzylamino group, chloro-substituted dibenzylamino group, etc. represents a halogen atom such as a cyalkylamino group, a nitro group, a cyano group, or an alkyl group such as a methyl group or an ethyl group. ] (181 is a hydrogen atom, a halogen atom such as chlorine, bromine, etc.
Alkyl group such as methyl group, ethyl group, ethyl group, alkoxy group such as methoxy group, ethoxy group, butoxy group or cyano group, Bit or R111 is a hydrogen atom, alkyl group such as methyl group, ethyl group, ethyl group, 2 - Substituted alkyl group such as chloroethyl group or 2-hydroxyethyl group, or substituted or unsubstituted benzyl group, R84
Or Hss is a hydrogen atom, a halogen atom such as chlorine or bromine, an alkyl group such as an ethyl group, an ethyl group, or an ethyl group,
It represents an alkoxy group such as a methoxy group, an ethoxy group, or an ethoxy group, or a dialkylamino group such as a dimethylamino group or a diethylamino group. Examples of the substituent on the benzyl group of HIS or R33 include alkyl groups such as methyl group and ethyl group, alkoxy groups such as methoxy group and ethoxy group, and nitro group. ] (Ar" represents an N-alkylcartumazolyl group.

Alkyl groups include methyl group, ethyl group, propyl group,
Examples include ethyl group. ]C:a a”, Ra
t, n@@hl [AW child s salt IL, bromine fx tof) Halogen atom, alkyl group such as methyl group, ethyl group, alkoxy group such as methoxy group, ethoxy group, nitro group or amino group, RI is hydrogen atoms, halogen atoms such as chlorine and bromine.

Alkyl groups such as methyl and ethyl groups, alkoxy groups such as methoxy and ethoxy groups, dialkylamino groups such as dimethylamino, diethylamino and dibutylamino groups, dibenzylamino groups, chloro-substituted dibenzylamino groups, methyl-substituted Substituted or unsubstituted cyalkylamino groups such as dibenzylamino groups, methoxy-substituted dibenzylamino groups, N-alkyl-N-aralkyl amino groups such as N-methyl-N-benzylamino groups, carboxy groups, or esters thereof , represents an amine group, a hydroxy group, a cyan group, and an acetylamino crystal. ] (140 represents an N-alkylcarbazolyl group, pyridyl group, dienyl group, indolyl group, furyl group, or a substituted or unsubstituted naphthyl group, styryl group or anthryl group. Naphthyl group, styryl group, Examples of substituents on the anthryl group include alkyl groups such as methyl and ethyl groups, alkoxy groups such as methoxy and ethoxy groups, and dialkylamino groups such as dimethylamino and diethylamino groups.] (141, R41! hydrogen atom, methyl group, ethyl group,
Alkyl groups such as butyl groups, methoxy groups, ethoxy groups,
Alkoxy groups such as butoxy groups.

Represents a halogen atom such as chlorine or bromine, or a dialkylamino group such as a dimethylamino group or diethylamino group, and n
l represents 0 or 1. ]47 (14m, R44 is a hydrogen atom, 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 halogen atom such as chlorine, R41, R4+1
represents an alkyl group such as a methyl group, ethyl group, propyl group or butyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and 7 represents a hydrogen atom or a substituted or unsubstituted phenyl group. 84m, 14+1
An example of the a2/L/kyl group is a benzyl group, and an example of the aryl group is a phenyl group. Also,
Examples of substituents on aralkyl or aryl groups include alkyl groups such as methyl, ethyl, and butyl, alkoxy groups such as methoxy and ethoxy, halogen atoms such as chlorine, and dialkylamino groups such as dimethylamino and diethylamino groups. can be exemplified. ] [R4@, R41 represents an alkyl group such as a methyl group or an ethyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted benzyl group. Examples of the substituent include alkyl groups such as methyl group and ethyl group, and alkoxy groups such as methoxy group and ethoxy group. ] (RIG and R111 represent the same groups as R41 and R41+ above.) R cage (Hsm is a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, a substituted or unsubstituted phenyl group, or an unsubstituted N-furkyl carboxyl group) Represents a zolyl group, where Hsm
is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a substituted amino group (R11
4, R 6 represents an alkyl group such as a methyl group, ethyl group, propyl group or butyl group, a substituted or unsubstituted aralkyl group such as a benzyl group, or a substituted or unsubstituted aryl group such as a phenyl group.

Further, R84 and RIB may form a ring. ), m represents an integer of 0, 1, 2 or 3, and when m is 2 or more, RII'' may be the same group or a different group. As a substituent in the aralkyl group or aryl group in R54 or R11IIVC Examples include alkyl groups such as methyl, ethyl, propyl, and ethyl groups, alkoxy groups such as methoxy and nidoxy groups, halogen atoms such as chlorine, and dialkylamino groups such as dimethylamino and diethylamino groups. ] Further, specific examples of these charge transport substances are as follows.

Compound point structure formula l
CH.

C! H.

Compounds & Tanks Formula% Formula% ) Compound & Structure Formula 0 heavy H.

Compound A Structure Formula Compound Point Structure Formula Compound A
Structural formula 4 to -28 Compound point Structure Formula compound plate structure Formula chemical hardware shop
Structural formula -39 -40 -41 Compound A Structural formula compound point Structural formula compound point
Structural hardware store
Structural Formula In addition to the above-mentioned exemplified compounds, polymer substances include poly/N-pinyl carnosol, halogenated
Condensation resins such as N-vinylcarbachyjL/, polyvinylpyrene, bromo2rene-formaldehyde condensation 41 resin, N-ethylcarbazole-formaldehyde condensation resin, and low molecular weight substances such as oxazole derivatives, oxadiazole visiting conductors, and fluorenone. Any of the known charge transport materials such as nitro derivatives are effective.

The accompanying drawings are representative enlarged sectional views of two sides of the electrophotographic photoreceptor according to the present invention, and FIG. FIG. 2 shows a conductive support 1 provided with a photosensitive layer 41.
1, a 'load generation layer 22. A charge transport layer 32 is provided to form a multilayer photosensitive layer 42i. Compared to the former, the latter electrophotographic photoreceptor (shown in FIG. 2) having a product of Nm is more advantageous in various respects. 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 includes a metal plate, metal drum, or metal foil made of aluminum, nickel, chromium, etc., and aluminum, tin oxide, indium oxide, chromium, J? Plastic films provided with a thin layer of radium or the like, paper or plastic films coated with or impregnated with a conductive substance, etc. are used.

In a laminated type photoreceptor, the charge generation layer 22 is a liquid 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 and dispersed in an appropriate solvent, or as necessary. A dispersion in which a binder resin is dissolved is coated on a conductive support, 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 this charge generation layer 22 is 0.01 to 5 μm.

It is 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.

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, the ratio of the disazo pigment in the charge generation layer 22 is 101
Sensitivity is poor when the amount is less than i.

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 ratio of the charge transport material contained in the charge transport layer 32 is 10 to 80% by weight, preferably 25% by weight.
~75. The film thickness is 2 to 100 μm.

Preferably it is 5 to 40 μm. If the ratio of the charge transport substance contained in the charge transport layer 32 is less than 1OZ, the sensitivity will be poor, and if it is more than 80J, the film will become brittle or crystals will precipitate, making the charge transport layer 32 cloudy, which is not preferable. ,Also,
If the thickness of the charge transport 1@32 is 2 μm or less, the potential is not maintained well (and if it 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, zotyral 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.

Further, as the binder resin for the charge transport layer 32, polycarbonate resin and polyester resin are used.

Examples include polystyrene, polyurethane resin, epoxy resin, acrylic resin, silicone resin, and copolymers thereof.1. They may be used alone or in a mixture of two or more.

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.

Unfortunately, in the photoreceptor of the present invention, if necessary, a K/1 rear layer between the conductive support 11 and the charge generation layer F@22, an intermediate layer between the charge generation layer 22 and the charge transport layer 32, and a charge transfer layer are provided. It is also possible to provide an oat layer on the transport layer 32.

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

Example 1 Disazo compound Al~32 was mixed in 14 parts of 76M, 1260 parts by weight of a tetrahydrofuran d solution (solid content concentration 2%) of polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.), and 3700 parts by weight of tetrahydrofuran in wi-lumil. After grinding and mixing, the resulting dispersion was coated on the aluminum surface of the aluminum-deposited polyester paste (conductive support) using a nine-doctor blade, and air-dried.
A charge generation layer having a thickness of about 1 μm was formed. - incoming charge transport,
Substance & 2-29 Y 2 parts by weight.

Mix and dissolve 2 parts by weight of polycarmenate resin (1300° manufactured by Teijin Co., Ltd.) and 16 parts by weight of Tetra-Cracked resin (1300°) in an arm light to make a solution. Apply with a blade and dry at 80°C for 2 minutes and at 100°C for 5 minutes to obtain a J'f-size of approximately 20μ.
A layered Al photoreceptor as shown in FIG. 2 was prepared by forming a charge transport layer of m.

Examples 2 to 10 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 A I-32 and charge transport substance 2-29 used in Example 1. Photoconductors A2 to A10 were produced in the same manner. These photoconductors A2 to A10 were tested at -6 KV using a copy paper testing device (SP 42 B type, manufactured by Kuyokuchi Denki Seisakusho). After performing corona discharge for 20 seconds to make it negatively charged, it was left in a dark place for 20 seconds, the surface potential Vpo (V) at that time was measured, and then the surface was illuminated with a tungsten lamp at an illuminance of 4.5 lux. The time (seconds) it takes for the surface potential to reach −Vpo after irradiation with light is calculated, and the exposure amount E (looks/second) is calculated. The results are shown in Table 1.

Table 1 In addition, the photoreceptor AI 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 repeating 10,000 times. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

The electrophotographic photoreceptor of the present invention has excellent properties such as being easy to manufacture and having stable characteristics even after repeated use of the photoreceptor.

[Brief explanation of the drawing]

1 and 2 are enlarged sectional views showing two typical sides of the electrophotographic photoreceptor of the present invention. 11... Conductive support 21... Charge generating substance 2
2... Charge generation @ 31... Charge transport substance 3
2...Charge transport layer 41.42...Photosensitive layer
1 Figure complete 2 figures

Claims (1)

[Claims] 1. The following general formula (1) (where 'R
1 and R2 represent hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic group, or a substituted or unsubstituted heterocyclic group. Here, R1
and R3 may be the same or different, and 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.