JPS63148263A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance solution stability and coating efficiency by incorporating as the binder resin of a photosensitive layer a modified polycarbonate resin having specified repeating structural units as an essential component. CONSTITUTION:The electrophotographic sensitive body is provided on a conductive substrate the photosensitive layer containing the modified polycarbonate resin having the repeating structural units each represented by the formula shown on the right in which each of R<1> and R<2> is H atom, 1-3C, alkyl group, or halogen atom, and at least one of them is alkyl group; each of R<3> and R<4> is H atom or 1-3C alkyl group. As the conductive substrate, a metallic material, such as aluminum or nickel, or an insulating support, such as polyester film or paper, coated with a conductive material, such as aluminum, is used, and on this substrate a dispersion type or laminate type or the like photosensitive layer is formed, thus permitting solubility and storage stability of the solution to be enhanced.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor), and more specifically, it relates 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 and applied not only in the field of copying machines but also in the field of various printers, etc., because of its ability to provide instantaneous 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, which have advantages such as ease of manufacture, have been developed and are making a lot of noise.

Examples of organic photoreceptors include 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 to be Solved by the Invention J] However, conventional organic laminated photoreceptors have been developed that have sufficient characteristics and durability in terms of electrical performance such as sensitivity and chargeability. In terms of physical properties, it has drawbacks such as friction and surface scratches due to practical loads such as development with toner, friction with paper, and friction due to cleaning materials, although the load varies depending on the method. Therefore, in practice, the printing durability is limited at present.

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, as well as various curable resins. However, the charge transfer layer usually consists of a solid solution of a binder resin and a charge transfer agent, and the amount of doping of this charge transfer agent is a considerable length A, so that it does not have sufficient surface strength. Therefore, when used in a process that uses a normal blade cleaning method, the image quality deteriorates due to surface abrasion and scratches after several thousand to ten thousand copies are made, and the photoreceptor must be replaced.

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

However, commonly used commercially available polycarbonate resins are crystalline and therefore have poor solution stability.Although a homogeneous solution can be obtained at the initial stage, crystallization gradually progresses and the gel content increases. I will do it. When such a liquid is used for coating, a uniform coating film cannot be obtained, which is a major factor in reducing the coating efficiency.

[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 provides sufficient solution stability and has excellent mechanical performance. Ta.

That is, the gist of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer on a conductive support, in which a modified polycarbonate resin having a repeating structural unit represented by the following general formula (1) is used as a binder resin for the photosensitive layer. An electrophotographic photoreceptor characterized by containing as a main component.

(However, in the formula, R1 and P are hydrogen atoms, number of carbon atoms/~3
selected from an alkyl group and a halogen atom, R1 and R
At least one of 1 represents an alkyl group. R” and R
' represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ) Hereinafter, the present invention will be explained in detail.

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 aluminum, copper, palladium, tin oxide, and indium oxide on the surface, and insulating supports such as paper. is used.

A photosensitive layer of a dispersed type, a laminated type, etc. is provided on such a conductive support, and a known barrier layer commonly used may be provided in between. For example, metal oxides such as aluminum oxide, resin layers such as polyamide, polyurethane, cellulose, casein, etc. can be used. In the case of a dispersed photoreceptor, organic pigments such as selenium and its alloys, cadminolene sulfide pigments, polycyclic quinone pigments, and benzimidazole pigments can be used.

In the case of a laminated photoreceptor, the charge generation layer can be made of the various photoconductive materials mentioned above, and either a uniform layer of these materials or fine particles of these materials can be used as a charge generating layer. It is used bound with various binder resins such as polycarbonate, polyvinyl butyral, phenoxy resin, cellulose ester, cellulose ether, urethane resin, and epoxy resin. The thickness of this layer is usually 0.18m to 1μm
1 preferably 0.1! A range of .mu.m to O-6 .mu.m is preferred.

In addition, as a charge transfer material for the charge transfer layer, −2+ ”
+ Electron-withdrawing substances such as 7-dolinitrofluorenone and tetracyanoquinodimethane; heterocyclic compounds such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, and thiadiazole; derivatives of aniline; Examples include electron-donating substances such as conductors, hydrazone, or polymers having a group consisting of these compounds in the main chain or side chain.

Among these, the following general formula (21 (formula, R1 represents an alkyl group, a substituted alkyl group, or an aralkyl group, and R6 represents an alkyl group, an allyl group, a substituted alkyl group,
It represents a phenyl group, a naphthyl group, or an aralkyl group, and zl represents a hydrogen atom, an alkyl group, an alkoxy group, or If a halogen atom. ) (see JP-A Sho!≠-/!0121) or the following general formula (3) (wherein, XI, yl, zl are hydrogen atoms, lower alkyl groups, lower alkoxy groups, represents a phenoxy group or an arylalkoxy group, R? represents a hydrogen atom, a lower alkyl group, an allyl group, a phenyl group or an aralkyl group, m and t represent/or i, p
It is preferable to use hydrazone compounds represented by O or /) alone or in combination.

Furthermore, the non-charged @ layer of the present invention contains a well-known adhesive agent to improve film formability, flexibility, and mechanical strength, and well-known additives to suppress the accumulation of residual potential. It may also contain additives.

The modified polycarbonate resin of the present invention has the general formula [1
It has a repeating structural unit shown by 1. Usually, the molecular weight is about 10,000-yo in terms of viscosity average molecular weight.
It is the range of o o o. Such a modified polycarbonate resin can be advantageously used as a binder resin for the photosensitive layer. When the photosensitive layer has a layer loss history, the modified polycarbonate resin of the present invention may be used as a binder for either the charge generation layer or the charge transfer layer, but it is preferably used as the binder for the charge transfer layer.

The modified polycarbonate resin of the present invention has the following general formula (4
) can be easily synthesized according to a conventional method using a phenolic compound selected from

(However, in the formula, R', R'', R'' and R' have the same meanings as above, and at least one of R1 and R1 represents an alkyl group.) Here, the phenol type represented by the general formula (4) Specific examples of the compounds include co,2-bis(Hiro-hydroxy-j-methylphenyl)-propane, λ-pis(4L-hydroxy-3,r-dimethylphenyl)-propane, -2-bis(4t -Hydroxy-3-chloro-yo-methylphenyl)propane,! , Cocose [Kouhydro Palm 3-(
-1propyl)phenyl)furopane, /l/-bis(≠
-hydroxy-3-methylphenyl)ethane, /, /-
Bis(4t-hydroxy-3,j-dimethylphenyl)
Examples include bis(hydroxyphenyl) alkanes such as ethane.

To produce the modified polycarbonate resin of the present invention, specifically, in the presence of an inert solvent such as methylene chloride or λ-dichloroethane, an aqueous alkaline solution or pyridine or the like is added as an acid acceptor to the phenolic compound, React while introducing phosgene.

When using an alkaline aqueous solution as an acid acceptor, the reaction rate can be increased by using a tertiary amine such as trimethylamine or triethylamine, or a μ-class ammonium compound such as tetrabutylammonium chloride or benzyltriphthylammonium bromide as a catalyst. do.

Phenol, p-
A phenol equivalent to tertiary-butylphenol may also be present.

The catalyst may be added from the beginning, or may be added after the oligomer is prepared to increase its molecular weight.

In the present invention, any modified polycarbonate resin having a repeating structural unit represented by the general formula (1) as the main component may be used, and other components may be added to the extent that the effects of such structural units are not impaired. For example, Bis (4!
-hydroxyphenyl)methane, /, /-bis(≠
Bis(hydroxyphenyl) alkanes such as -hydroxyphenyl)ethane, λ, 2-bis(≠-hydroxyphenyl)propane, and λ9.2-bis(Hiro-hydroxyphenyl)butane are represented by the above general formula (1). Modified polycarbonate resin 100 having repeating structural units
They may be used in combination within a range of 5 parts by weight or less.

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

〔Effect of the invention〕

Since the modified polycarbonate resin of the present invention has excellent solubility and solution storage stability, the productivity of photoreceptors is greatly improved, such as by extremely reducing the occurrence of defects during coating on photoreceptors.

In addition, when the photoreceptor using the modified polycarbonate resin of the present invention is used repeatedly, there is little change in sensitivity and chargeability, and since it has excellent mechanical properties, there is almost no film peeling due to cleaning blades, etc., and therefore it is durable. is extremely good.

Furthermore, the photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in lasers,
It can also be widely used in electrophotographic applications such as photoreceptors in printers using LEDs, LCDs, cathode ray tubes (CRTs), and the like as light sources.

〔Example〕

Next, the present invention will be explained in more detail with reference to production examples and examples, but the present invention is not limited thereto unless it exceeds the gist thereof.

In addition, "parts" in the production examples and examples indicate "parts by weight."

Production example / ←) Production of polycarbonate oligomer λ, -monobis(guhydroxy-3-methylphenyl)propane
100 parts sodium hydroxide
30 parts water
♂ 70 parts methylene chloride 530 parts p-tert-butylphenol λ. θ part: Charge the above mixture into a reactor equipped with a stirrer, and mix at ♂00 rpz.
It was stirred with 70 parts of phosgene was blown into this for one hour to effect interfacial polymerization. After the reaction was completed, 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 concentration (Note 1),! 4t, o heavy terminal chloroformate group concentration (Note 2) o, zb
Specified terminal phenolic hydroxyl group concentration (Note 3) o,
i3 standard Note 1) Measurement by evaporation to dryness 2) Aniline hydrochloride obtained by reacting with aniline is
l, Neutralization titration with 2N aqueous sodium hydroxide solution 3) 12! ] Colorimetric determination of color development when titanium chloride is dissolved in acetic acid solution at 3 tl lr nm.

The oligomer solution obtained by the above method is hereinafter abbreviated as oligomer solution A.

(b) Production of modified polycarbonate resin Oligomer solution A 260 parts Methylene chloride
ioo part p-tert-butylphenol
0.3 part was charged into a reactor equipped with a stirrer, and stirred at 1/2 Orpm. Furthermore, an aqueous solution having the following composition was charged and interfacial polymerization was carried out for 3 hours.

Sodium hydroxide l Hirobe triethylamine 0.07 parts water
Subsequently, the reaction mixture was separated, and the methylene chloride solution containing the polycarbonate resin was washed with cold water, an aqueous hydrochloric acid solution, and water. Finally, the methylene chloride was evaporated to remove the resin.

The average molecular weight 1 of this resin was μIt, 20t).

*The average molecular weight referred to here is a value determined from the following formula (1) and formula (2) from η8p measured at 20°C using a methylene chloride solution of polymer 6 and θl/l.

ηθp10=rη] (/ten'ηap)
・・・・・・(1) [η)==K“1
...... (in formula 21 O: polymer concentration y/
l [η]: Intrinsic viscosity 'xO, -r K=/, 2JX/θ-6 α = O0♂3 M: Average molecular weight Example 1 Regarding the modified polycarbonate and commercially available polycarbonate shown in Table (1), To compare their solution stabilities, 10% solution of tetrahydrofuran was added to each
ii14 was prepared and left at room temperature for 7 months, and the viscosity of the solution was measured.

As a result, commercially available polycarbonate (Nipiron A-10OO, manufactured by Mitsubishi Gas Chemical 1) became completely cloudy for io days, and
In contrast, the modified polycarbonates of the present invention did not turn into cloudy gels even after one month, and no change in viscosity was observed.

Example λ A bisazo compound having the following structure IO part, 5 parts of phenoxy resin (PKHH manufactured by Union Carbide Co., Ltd.), z part of polyvinyl butyral resin (BH-3 manufactured by Block Chemical Industry Co., Ltd.), Hiro-methoxy-μm methylpentanone -λ 700 parts were added, and pulverization and dispersion treatment was performed using a sand grind mill. The obtained dispersion was applied with a film applicator onto an aluminum vapor-deposited layer coated with a polyester film having a thickness of 100 μm so that the dry film thickness satisfied O1≠I/go, and then dried.

On the charge generation layer thus obtained, 20 parts of N-methylcarbasol-3-aldehyde diphenyl crack 21,
and 100 parts of modified polycarbonate resin A shown in Table (1) of Example 1, a cyano compound having the following structure≠,
! A solution dissolved in 200 parts of Hehiro-dioxane was applied to form a charge transfer layer to a dry film thickness of 17 μm.
A laminated photoreceptor λ-A was created.

The characteristics of the photoreceptor thus obtained were measured as follows. First, the corona current flowing into the photoreceptor in the dark is λμ
Corona discharge is carried out so that A is passed through the photoreceptor at a constant speed (/!θ gate/day θC) to charge it, and the charging voltage is measured, and the initial charging voltage is ■. I asked for Next, the photoreceptor was exposed to white light having an illuminance of J tux, and the amount of exposure (El!%) required to reduce the surface potential of the photoreceptor by half of the initial charged voltage was determined. The results are shown in Table 21.

In place of the modified polycarbonate resin used in Example 3 and Ko Example, modified polycarbonate resin B in Table (1) of Example
, O were used, and photoreceptors J-B and Hiroshi-0 were prepared in the same manner as in Example 1, respectively, and their characteristics were measured in the same manner as in Example λ.

The results are shown in (2).

Comparative Example/Used in Example λ1. nfcx polycarbonate glue
Then, a photosensitive ¥4i:/-D was prepared in the same manner as in Example λ using commercially available polycarbonate (Nipilon B-1000 manufactured by Mitsubishi Gas Chemical Co., Ltd.).

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

Table (2) As can be seen from Table (2), the photoreceptor of the present invention is superior in electrical performance to photoreceptors using commercially available polycarbonate.

Example - An aluminum cylinder with a mirror-finished surface was dip-coated in the pigment dispersion used in Example-, and the film thickness after drying was O.
The charge generation layer was provided so that 1≠μm. Next, this aluminum cylinder was dip-coated in a Hehiro-dioxane solution of the charge transfer agent used in Example λ, modified polycarbonate, and a Kr4L cargo transfer layer was provided so that the film thickness after drying was 204 m.

The drum-shaped photoreceptor thus produced is designated as j-E.

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

As a result, in the copy of the ψ stick, there was almost no mechanical film υ due to the Mori IJ + Bunning I radar, and no deep scratches were found on the surface of the photoreceptor. No black streaks that were considered to be caused by scratches appeared on the copy image, and a good copy image was obtained. Therefore, it can be judged that the mechanical properties are extremely excellent, and the potential properties are as shown in Table (3).
It can be judged that it is extremely stable and has sufficient durability.

Table (3) As is clear from the above results, the modified polycarbonate of the present invention is considered to have excellent performance as a binder resin for electrophotographic photoreceptors.

Employer: Mitsubishi Chemical Industries, Ltd. Agent Patent Attorney Hase - Others/names

Claims (1)

[Scope of Claims] In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, a binder resin of the photosensitive layer may be a binder resin of the following general formula (1).
) An electrophotographic photoreceptor characterized by containing as a main component a modified polycarbonate resin having a repeating structural unit represented by: ▲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 represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. )