JPS62212661A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To decrease the fluctuation of sensitivity and electrostatic chargeability in repetitive use and to improve durability by using a specific modified polycarbonate resin as a binder resin of a photosensitive layer. CONSTITUTION:This electrophotographic sensitive body has the photosensitive layer on a conductive base. The binder resin of the photosensitive layer contains the modified polycarbonate resin having the repeating structural unit expressed by formulas I and II. The modified polycarbonate resin is synthesized according to the conventional practice by using >=2 kinds of phenolic compds. selected from formulas III and IV. The ratio of the amt. of using the phenolic compds. expressed by formulas III, IV is 20:80-95:5, more preferably 30:70-90:10. In formula, R<1> and R<2> denote a hydrogen atom and a group which are selected from an alkyl group of 1-3C and halogen atom, at least one of which denotes an alkyl group, R<3> and R<4> respectively independently denote an alkyl group of 1-3C or hydrogen atom.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor that uses a specific binder resin and has excellent durability. .

[Conventional technology]

In recent years, electrophotographic technology has been widely used not only in the field of copying machines but also in the field of various printers, as it can produce instant images and high-quality images.

Photoconductive materials for photoreceptors, which are the core of electrophotographic technology, range from conventional inorganic conductors such as selenium, arsenic-selenium alloys, cadmium sulfide, and zinc oxide to lightweight, easy-to-form, and Photoreceptors using organic photoconductive materials have been developed, which have advantages such as ease of manufacture.

As organic photoreceptors, there are so-called dispersion type photoreceptors in which photoconductive fine powder is dispersed in a binder resin, and laminated type photoreceptors in which a charge generation layer and a charge transfer layer are provided on a conductive support. However, the latter type is in practical use due to its high sensitivity and high printing durability.

[Problem that the invention seeks to solve]

However, conventional organic layered photoreceptors have been developed that have sufficient characteristics and durability in terms of electrical performance such as sensitivity and chargeability, but in terms of physical characteristics,
In other words, the load varies depending on the method, such as development with toner and friction with paper, but practical loads such as friction with cleaning members can cause wear and surface scratches, so there is a limit to practical use. The current situation is that the printing durability remains at the same level as expected.

Conventionally, binder resins for charge transfer layers include thermoplastic resins such as polycarbonate resins, acrylic resins, methacrylic resins, polyester resins, polystyrene resins, silicone resins, epoxy resins, and polyvinyl chloride resins;
Various curable resins have been used, but the charge transfer layer usually consists of a solid solution of a binder resin and a charge transfer agent, and because the amount of charge transfer agent doped is quite large, it has sufficient surface strength. I have not yet reached the point where I can do it. Therefore, when using a printer using a normal blade cleaning method, the image quality deteriorates due to abrasion and scratches on the surface after making several thousand to ten thousand copies, and the photoreceptor must be replaced.

Among these binder resins, polycarbonate resin has relatively excellent mechanical performance and therefore has excellent printing durability.

However, commercially available polycarbonate resins that are commonly used have poor solution stability because they are crystalline, and although a homogeneous solution is obtained at the initial stage, crystallization gradually progresses and the gel content increases. . When spraying is performed using such a liquid, it is difficult to obtain a uniform coating film, which is a major factor in reducing the coating yield.

[Means to solve the problem]

Therefore, the present inventors conducted a detailed study on the binder resin of the photosensitive layer and found that a specific modified polycarbonate resin has sufficient solution stability and excellent mechanical performance, leading to the present invention.

That is, the gist of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer on a conductive support, in which repeating structural units represented by the following general formulas (1) and (2) are used as a binder resin for the photosensitive layer. An electrophotographic photoreceptor is characterized in that it contains a modified polycarbonate resin.

(However, in the formula, R1 and Htl family hydrogen atoms, carbon atoms 7
~3 alkyl groups and halogen atoms, R1
and with a small difference (both represent an alkyl group. Rz and R4 each independently represent a carbon atom number/-, 7 aA/
Represents a Φ group or a hydrogen atom. ) (However, in the formula, R3 and R4 have the same meaning as in the above general formula (1).) The present invention will be described in detail below.

The photoreceptor of the present invention is provided on a conductive support. Examples of conductive supports include metal materials such as aluminum, stainless steel, copper, and nickel, polyester films with conductive layers such as aluminium, copper, palladium, tin oxide, and indium oxide on the surface, and insulating materials such as paper. A support is used.

A photosensitive layer of a dispersed type, a laminated type, etc. is provided on such a conductive support, and a commonly used barrier layer may be provided between the photosensitive layers.

As the barrier layer, for example, a metal oxide such as aluminum oxide, a resin layer such as polyamide, polyurethane, cellulose, casein, etc. can be used. In the case of a separation type photoreceptor, photoconductive materials include selenium and its alloys, cadmium sulfide, other inorganic base conductors, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, Organic pigments such as benzimidazole pigments can be used.

In the case of a laminated type photoreceptor, each of the above-mentioned 8-component conductive materials can be conveniently used as the charge generation layer. It is conveniently used in a form bound with various binder resins such as polyester, polycarbonate, polyvinyl butyral, phenoxy resin, cellulose ester, cellulose ether, urethane resin, and epoxy resin. The thickness of this layer is usually 0.1 μm to 1 μm.
Preferably 0.1! Rμm to o, bμm is suitable.

In addition, charge transfer materials for the charge transfer layer include electron-withdrawing substances such as -9-trinitrofluorenone and tetracyanoquinodimethane, cal/<''/-ol, indole, imidazonyl, oxazole, thiazole, and oxadiazole. Examples include electron-donating substances such as heterocyclic compounds such as , pyrazole, pyrazoline, and thiadiazole, aniline derivatives, hydrazine derivatives, hydrazone, and polymers having a group consisting of these compounds in the main chain or IN chain.

Among these, the following general formula (3) (wherein R6 represents an alkyl group, substituted alkyl group, or aralkyl group, and R. is an alkyl group, allyl group, substituted alkyl group,
represents a phenyl group, a naphthyl group, or an aralkyl group, and 21 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ) or the following general formula (4) (where xl, Yl, Z- are hydrogen atoms, lower alkyl groups, lower alkoxy groups, represents a phenoxy group or an arylalkoxy group; R1 represents a hydrogen atom, a lower alkyl group, an allyl group, a phenyl group, or an aralkyl group; m and ) represent a group; p represents 0 or l;
represents. ) It is preferable to use the hydrazone compounds represented by the formulas alone or in combination.

Furthermore, the charge immobile layer of the present invention may contain a well-known plasticizer to improve its dispersion property, flexibility, and mechanical strength, and a well-known additive such as a well-known additive to suppress the accumulation of residual potential. It may contain additives.

The modified polycarbonate resin of the present invention has the general formula (1
) and (2). Usually, the molecular weight is the viscosity average molecular weight of about io, θ0
0~! The range is 0,000. Such a modified polycarbonate resin can be advantageously used as a binder resin for the photosensitive layer. If the photosensitive layer is a laminated type, t? Although it may be used as a binder for either the IIT generation layer or the charge transfer layer, it is preferably used as a binder for the charge transfer layer.

The modified polycarbonate resin of the present invention has the following general formula (5
) and (6) can be easily synthesized according to a conventional method using one or more phenolic compounds selected from (6).

(However, in the formula, R1, R1, R1 and R4 have the same meaning as above, and at least one of R1 and R2 represents an alkyl group.) R@ (However, in the formula, R1 and R4 have the same meaning as above. .

) The fecal volume ratio of the phenolic compound of the above general formula (5) and the phenol compound of the above general formula (6) is 10:1!
: 0'～DE! versus! , preferably 30:70 to qO
Selected from the range of vs. IO.

Specific examples of the phenolic compound represented by the general formula (5) include co-, Corbis (lI-hydroxy-J-methylphenylene Jv)-propane, 2. Corbis (Tacht a)
xy-,t,r-dimethylphenyl)-furopane,
Yu, Nibis(Hiro-hydroxy-3-chloro-5-methylphenyl)propane, -9-bis[Cuhydroxy-3-(=-propyl)-phenyl]furopane, /, /
Bis(hydroxyphenyl) alkanes such as -bis(ll-hydroxy-3-methylphenyl)ethane, /,/-bis(cuhydroxy-3,!-dimethylphenyl)ethane', and the like.

Specific examples of the phenolic compound represented by general formula (6) include bis(Hiro-hydroxyphenyl)methane, 1.
Examples include l-bis(hydroxyphenyl)alkanes such as 1-bis(terhydroxyphenyl)ethane, co-, -1bis(+-hydroxyphenyl)propane, and -12-bis(terhydroxyphenyl)furan.

The method for producing the modified polycarbonate resin of the present invention includes:
Specifically, in the presence of an inert solvent such as methylene chloride or 1,-1-dichloroethane, an aqueous alkaline solution or pyridine as an acid acceptor is added to the phenol compound, and the reaction is carried out while introducing phosgene.

When using an alkaline water bath solution as an acid acceptor, the reaction rate can be increased by using a tertiary amine such as trimethylamine or triethylamine, or a secondary ammonium compound such as tetrabutylammonium chloride or benzyltributylammonium bromide as a catalyst. increase

Phenol, p-
A phenol equivalent to Tasha IJ-7' tylphinol may also be present. The catalyst may be added from the beginning, or any method may be used, such as adding it after the oligomer is produced to increase the molecular weight.

In the present invention, methods for copolymerizing using two or more phenolic compounds include: 0) A method in which two or more phenolic compounds are first simultaneously reacted with phosgene and copolymerized (=) One of them is first reacted with phosgene. A method in which one reacts with phosgene, and after a certain amount of reaction, the other is added and polymerized (→
Any method can be used, such as a method of separately reacting with phosgene to produce oligomers and reacting them to polymerize.

The modified polycarbonate resin of the present invention thus obtained has excellent solubility in organic solvents, and has excellent solubility in organic solvents.
/, 4(-It also shows high solubility in non-halogenated solvents such as dioxane and tetrahydrofuran, and since coating liquids can be prepared using these solvents, there are few safety and health problems.

〔Effect of the invention〕

The photoreceptor using the modified polycarbonate resin of the present invention is
When used repeatedly, there is little change in sensitivity and chargeability (,
Therefore, the durability is extremely good.

Further, the photoreceptor of the present invention can be widely used in electrophotographic applications such as photoreceptors for printers using lasers, II% LCDs, cathode ray tubes (0!tT), etc. as light sources, as well as electrophotographic copying machines. .

〔Example〕

Next, the present invention will be explained in more detail with reference to production examples and examples, but these are not intended to limit the present invention. In addition, "parts" in the production examples and examples indicate "parts by weight."

Production Example 1 (a) Production of polycarbonate oligomer λI--bis(41-hydroxy-3-methylphenyl)furopane
100 parts Sodium hydroxide 3
0 parts water 17
0 part methylene chloride z, yo part p-tert-butylpheno-N, part Q The above mixture was charged into a reactor equipped with a stirrer and stirred at go rpm. 70 parts of phosgene was blown into this for one hour to effect interfacial polymerization. After reaction n7, only the methylene chloride solution containing the polycarbonate oligomer was collected.

The analysis results of the methylene chloride bath solution of the obtained oligomer were as follows.

Oligomer concentration (note/) 211.0 wt%
Terminal chloroformate group concentration (Note-) 0. jr & defined terminal phenolic water group concentration (Note 3) 0. /3 Regulations Note /
) Evaporate to dryness and measure aniline hydrochloride obtained by reacting with aniline.
．． Neutralization titration with 2N sodium hydroxide solution IW.

3) Color development when titanium tetrachloride is dissolved in acetic acid solution is t4! Colorimetric determination in am.

1) Sesame obtained by the above method! ff is hereinafter abbreviated as oligomer solution-person.

←) Production of polycarbonate oligomer 76.6% sodium salt of bisphenol A prepared by dissolving bisphenol A in aqueous sodium hydroxide solution Solution #100 parts p-tert-butylphenol Q, 23 parts Methylene chloride 10 parts phosgene
7 parts of the mixture having the above composition was quantitatively supplied to a pipe reactor to perform interfacial polymerization.

The reaction mixture was separated and only the methylene chloride solution containing the polycarbonate oligomer was collected.

The analysis results of the obtained oligomer solution in methylene chloride were as follows.

Oligomer degree A - dry! The oligomer solution obtained by the method having a weight-bearing terminal roloformate group concentration of 1.3N and a terminal phenolic hydroxyl group concentration of 0.3N or more is hereinafter abbreviated as oligomer solution fi-B.

(c) Production of copolymerized polycarbonate Oligomer solution-A 710 parts Oligomer solution-B 10 parts Methylene chloride
700 parts p-tert-butylphenol
0. Charge j parts into a reactor with a stirrer, and add z s o
Stirred at rpm. Furthermore, prepare a water bath liquid with the following composition 3
Time interfacial polymerization was performed.

Sodium hydroxide 114 parts Triethylamine 0.07 part Water
Subsequently, 30 parts of the reaction mixture were separated, and the methylene chloride solution containing the polycarbonate resin was washed with water, an aqueous hydrochloric acid solution, and water, and finally the methylene chloride was evaporated to take out the resin.

The average molecular r of this resin was /3.5θ0.

Further, from the results of NMR analysis, the amount of copolymerized bisphenol A was found to be 1.0%.

*The average molecular weight is a value determined from the following equations (1) and (2) from ηsp measured at 10° C. using a methylene chloride solution of polymer 6.0971.

ri5p10=Cri] (/+ to 'ηsp)...
...(1) [ri]=xKM”・
-1-(2) In the formula, C polymer concentration E/It [ri] Intrinsic viscosity '=0. -t K=/, 2JX10-s α=0. Example of Average Molecular Weight / In order to compare the solution stability of the modified polycarbonate and commercially available polycarbonate shown in Table (1), a 70% solution of tetrahydrofuran was prepared for each, and the solution was left at room temperature for an evening. , the solution viscosity was measured.

As a result, while the commercially available polycarbonate (Nipilon 5-tooo manufactured by Mitsubishi Gas Chemical Co., Ltd.) became completely cloudy and gelled within 10 days, the modified polycarbonate of the present invention remained completely cloudy even after 1 month. , white turbidity, and gelation did not occur - Part io of a bisazo compound having the following structure, 5 parts phenoxy resin (PKHIII manufactured by Union Carbide Co., Ltd.), polyvinyl butyral resin (13H manufactured by Sekisui Chemical Co., Ltd.), ?
) 2700 parts of 4(-methoxy-Hiro-methylpentanone) was added to part J, and pulverization and dispersion treatment was performed using a sand grind mill.

The obtained dispersion was applied with a film applicator to an aluminum vapor-deposited layer deposited on a polyester film having a thickness of 100 μm using VC so as to have a dry film thickness of 7 mm, and then dried.

90 parts of N-methylcarbasol-3-aldehyde diphenylhydrazone,
and modified polycarbonate resin hioo part shown in Table (1) of Example-7, cyano compound da of the following structure, 5
A charge transfer layer is formed by applying a solution in which 1 part is dissolved in 7900 parts of dioxa to a dry film thickness of 7900 parts, and a charge transfer layer is formed.
A laminated type photoreceptor code A was prepared.

The characteristics of the photoreceptor thus obtained were measured as follows. First, the corona current flowing into the photoreceptor in the dark is 2=
Corona discharge is performed at a constant rate (/j
011s/8eC) to pass through the sensory body and be charged, and the charging voltage was measured to determine the initial charging voltage Vo. then z
Exposure amount (K 172
) was sought.

The results are shown in Table (2).

Examples 3 to 6 The procedure was the same as in Example C, except that modified polycarbonate resins B, O, D, and Ift in Table (1) of Example fil/ were used instead of the modified polycarbonate resin used in Example C. and photoreceptor j-B, respectively.

Coo 0. &-D and A-K were prepared, and their characteristics were measured in the same manner as in Example-. The results are shown in Table (2).

Comparative Example-/Instead of the modified polycarbonate used in Example-Co,
A photoreceptor/-IF was prepared in the same manner as in Example-C using commercially available polycarbonate (Niepilon 8-7ooo, manufactured by Mitsubishi Gas Kashoshaso).

The characteristics of this photoreceptor were measured in the same manner as in Example-1. The results are shown in Table (2)K.

Table (2) ---A At de 7 l/de]
maeOj,? -B4riff A
1.26tI4(-0440A/Kodayo j-D412j/KoO At, -147yo Da t,2/[9jl-
/ /-IF Ate $ 13
As can be seen from Table 7 (2), it can be seen that the photoreceptor of the present invention has superior electrical performance compared to photoreceptors using commercially available polycarbonate.

Examples - A brushed aluminum cylinder was applied by dip coating to the pigment dispersion used in Example 1, and a charge generation layer was provided so that the r4 thickness after drying was 17 .mu.m. Next, this aluminum cylinder was dip-coated in a tI-dioxane solution of the charge transfer agent used in Example 1, modified polycarbonate, and a charge transfer layer was provided so that the film thickness after drying was: tO μm.

The drum-shaped photoreceptor thus produced is designated as 7-G.

In order to evaluate the durability of this photoreceptor, this photoreceptor was placed in a commercially available copying machine with a blade cleaning method and a soup copy test was conducted.

As a result, even after making 10,000 copies, no deep scratches were found on the sensory surface, and there were almost no swallow lines on the copy image that were thought to be caused by scratches, resulting in a good copy image. . Further, the potential characteristics are extremely stable as shown in Table (3), and it can be judged that it has sufficient durability.

Table (3) Initial 43;'OV/
/! 5 de OV after 10,000 copies of Vda
As is clear from the results of 9jTV and above, the modified polycarbonate of the present invention is considered to have excellent performance as a binder resin for electrophotographic photoreceptors.

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, a modified polycarbonate resin having repeating structural units represented by the following general formulas (1) and (2) is used as a binder resin for the photosensitive layer. An electrophotographic photoreceptor characterized by containing. ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………(1) (However, in the formula, R^1 and R^2 are selected from hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, and halogen atoms, and R ^
At least one of 1 and R^2 represents an alkyl group. R^3 and R^4 each independently have 1 to 3 carbon atoms;
represents an alkyl group or a hydrogen atom. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼……………(2) (However, in the formula, R^3 and R^4 have the same meaning as in the general formula (1) above.) (2) The modified polycarbonate resin has the general formula (1)
And the content ratio of the repeating structural unit shown in (2) is 20
The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor has a resin ratio of 80 to 95 to 5.