JPH01144057A - Photosemiconductive material and electrophotographic sensitive body using same - Google Patents

Abstract

PURPOSE:To obtain superior exposure sensitivity characteristics and wavelength characteristics, as well as characteristics resisting deterioration due to repeated use for a long period, printing resistance, and image stability by incorporating a tin-phthalocyanine derivative having intense peaks at the specified Bragg angles in the X-ray diffraction diagram. CONSTITUTION:The electrophotographic sensitive body uses an electric charge transfer material and as a charge generating material the tin-phthalocyanine derivative crystals having intense peaks at the Bragg angles (2theta+ or -0.2 deg.) of 8.6 deg., 12.2 deg., 14.9 deg., 17.4 deg., 19.4 deg., and 27.6 deg. in the diffraction diagram using the Cu-Kalpha line, thus permitting the obtained electrophotographic sensitive body to have superior exposure sensitivity characteristics and wavelength characteristics as well as deterioration resisting characteristics, printing resistance, and image stability at the time of repeated uses for a long period.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a photosemiconductor material useful for electrophotographic photoreceptors etc. that uses phthalocyanine containing tin as a central metal. In other words, it relates to an electrophotographic photoreceptor having excellent exposure sensitivity characteristics and wavelength characteristics.

(Conventional technology) Conventionally, selenium has been used as the photoreceptor for electrophotographic photoreceptors.

Inorganic photoconductors such as selenium alloys, zinc oxide, cadmium sulfide and tellurium have been used primarily. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost and are beginning to be used as light sources for electrophotography. but,
Using semiconductor lasers that emit short-wavelength light in these devices has many problems in terms of lifespan, output, etc. Therefore, the conventionally used materials sensitive in the short wavelength region are unsuitable for use in semiconductor lasers, and the materials sensitive in the long wavelength region (
It has become necessary to research materials with high sensitivity to wavelengths of 780 nm and above. Recently, research has been actively conducted on multilayer organic photoreceptors using organic materials, especially phthalocyanine, which is expected to have sensitivity in the long wavelength region. For example, as a divalent metal phthalocyanine,
ε-type copper phthalocyanine (ε-CuPc).

X-type metal-free phthalocyanine (X-H2PC) and τ-type metal-free phthalocyanine (τ-H2Pc) have sensitivity in the long wavelength region. As trivalent and tetravalent metal phthalocyanine, chloroaluminum phthalocyanine (AIPccl)
, chloroaluminum phthalocyanine chloride (C4
! AlPcC1), or titanyl phthalocyanine (T
iOPc), chloroindium phthalocyanine (InP
A method of vapor depositing cC1) and then contacting it with vapor of a soluble solvent to achieve long wavelength and high sensitivity (Japanese Patent Application Laid-Open No. 57-39484
JP-A No. 59-166959), a method in which phthalocyanine containing Ti, Sn, and Pb as Group Ⅰ metals is subjected to long wavelength treatment using various substituents, derivatives, or shifting agents such as crown ethers. (Special application 1982-
No. 36254, patent application No. 59-204045),
Sensitivity is obtained in the long wavelength region.

Furthermore, JP-A-57-148745 discloses tin.

Photoreceptors have also been reported in which a charge generation layer is made of a vapor-deposited film of metal phthalocyanine selected from metals such as aluminum, but these have extremely poor charging properties and are not practical.

After hot water treatment according to Japanese Patent Application Laid-Open No. 62-119547,
An electrophotographic photoreceptor provided with a charge generation layer containing a tin phthalocyanine compound purified by N-methylpyrrolidone treatment and a binder polymer may contain alcohols and ethers used before and after thermal suspension treatment with N-methylpyrrolidone. Due to its strong polarity, the crystal particles of the tin phthalocyanine compound strongly aggregate during the purification process, making Φ purification difficult. Acids and intermediate impurities generated during synthesis tend to remain in or on the surface of the a-collection particles, and for this reason, the N-methylpyrrolidone used in the next step decomposes and undergoes two reactions, resulting in a decline in electrical characteristics. do not have.

In these cases, the light absorption efficiency is insufficient, resulting in a decrease in the carrier generation efficiency of the charge generation layer, a decrease in the carrier injection efficiency into the charge transfer layer, and a decrease in deterioration resistance and rigidity resistance during repeated use over a long period of time. It had the drawback of not fully satisfying electrophotographic properties such as stability.

As mentioned above, there are 3 tin phthalocyanines that have been reported so far.
These are strongly aggregated lump particles, and since there are many impurities contained between the aggregated particles, which inevitably cause crystal growth during crystallization, and because the pigment particle size is large, they are used for vapor deposition and dispersion coating. The resulting charge generation layer lacked dispersion stability, resulting in a decrease in coatability. Thereby,
It has been difficult to obtain a homogeneous charge generation layer, and it has been difficult to obtain beautiful images and stable electrophotographic properties.

LEDs have also been put into practical use as digital light sources for printers. LEDs in the visible light range are also used, but those that are generally put into practical use have an oscillation wavelength of 650 nm or more, typically 660 nm+.

Azo compounds, perylene compounds, selenium, zinc oxide, etc.
Although it cannot be said that the phthalocyanine compound has sufficient photosensitivity at around 650 nm, it has an absorption peak around 650 nm, so it can be used as an effective material as a charge generating agent for LEDs.

(Problems to be Solved by the Invention) The purpose of the present invention is to provide excellent exposure sensitivity characteristics and wavelength characteristics, as well as deterioration resistance during repeated use over a long period of time.

The object of the present invention is to obtain an electrophotographic photoreceptor having rigidity resistance and image stability.

[Structure of the invention]

(Means and effects for solving the problems) The present invention has the following features:
This is a novel optical semiconductor material made using tin phthalocyanine compound crystal particles having an X-ray diffraction diagram showing a specific strong peak at the Bragg angle 2θ, and furthermore, an electron The above object has been achieved by an electrophotographic photoreceptor in which the charge generating agent is crystal particles of the novel tin phthalocyanine compound.

Specifically, we use (u-Kctg to calculate the Bragg angle (2
θ±0.2＠) 8.6°, 12.2°, 14.9＠.

A tin phthalocyanine compound having an X-ray diffraction diagram showing strong peaks at positions of 17.4°, 19.4° and 27.6° is selected.

The tin phthalocyanine compound used in the present invention is -
This is a compound represented by formula (III).

(In the formula, +R9 represents a halogen atom, an oxygen atom, an alkoxy group, and +R111 to R13 represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a nitro group, a cyano group, a hydroxyl group, a benzyloxy group, represents a substituent such as an amino group, j is an integer of 1 or 2, and I!, m, and n are integers of 0 to 4) The tin phthalocyanine compound of the present invention is defined by the type of substituent. , or the number of substitutions, the above-mentioned X-ray diffraction peak is observed.

Therefore, the Bragg angle (2θ±0.2”) is 8.6@.

Any tin phthalocyanine compound having strong peaks at the positions of 12.2", 14.9°, 17.4°, 19.4@ and 27.6" may be used, or two types thereof and It may be a mixture of three or more types.

Conventionally reported electrophotographic photoreceptors containing coarse crystalline secondary particles in the charge generation layer suffer from a decrease in light absorption efficiency.
The number of carriers generated decreases and the photosensitivity decreases. Furthermore, since the charge generation layer is non-uniform, the injection efficiency of carriers into the charge transport layer decreases, resulting in electrostatic properties such as induction phenomenon, decrease in surface potential, and potential stability during repeated use. Unfavorable phenomena occur in terms of the sensitivity of the photoreceptor, such as poor sensitivity. Further, even if the nine images are used, they lack homogeneity and produce minute defects.

As the tin phthalocyanine compound used as the charge generation layer, dihalogeno tin phthalocyanine (S n Cl1zPc) disclosed in JP-A-62-119547 is used.
, and C of λ=1.5418 (A, U, )
Using ukα radiation, 2θ (+2°) = 8.4°, 1
Although it has strong X-ray diffraction peaks at 3.8°, 22.4°, 28.2°, and 30.0", the material synthesized by the disclosed method and purified with a solvent is For various reasons, there are many problems, and it is difficult to say that it is a high-quality photoreceptor.

However, the two tin phthalocyanine compounds of the present invention are
It is a sufficiently uniformly finely divided crystal grain.

This is a new charge-generating material that compensates for the drawbacks of known dihalogenotin phthalocyanines.

Phthalocyanine can be produced by the phthalodinitrile method, in which phthalodinitrile and metal chloride are heated and melted or heated in the presence of an organic solvent; the Weiler method, in which phthalic anhydride is heated and melted with urea and metal chloride, or heated in the presence of an organic solvent; There are a method of reacting cyanobenzamide and a metal salt at a high temperature, and a method of reacting a dilithium phthalocyanine and a metal salt, but the methods are not limited to these. Examples of organic solvents include reaction-inactive high-boiling point solvents such as α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenylethane, ethylene glycol, dialkyl ether, quinoline, sulfolane, and dichlorobenzene. desirable.

The tin-containing phthalocyanine used in the present invention is [Phthalocyanine Compound J] by Moser and Torts.
(Moser and Thomas"Phtha
Compounds obtained by known methods such as "Locyanine Compounds") and the above-mentioned appropriate methods are combined with acids, alkalis, acetone, methyl ethyl ketone, tetrahydrofuran, pyridine, quinoline, sulfolane, α
-chloronaphthalene, toluene, dioxane, xylene, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, trichloropropane, N,N'-dimethylacetamide.

It is obtained by purification with N-methylpyrrolidone, N,N'-dimethylformamide, etc. Purification methods include solvent washing, recrystallization, extraction methods such as Soxhlet, and thermal suspension methods. It is also possible to purify by sublimation. Purification methods are not limited to these.

The crude compound may have any X-ray diffraction peak.

The crystal transition to the tin phthalocyanine compound having the X-ray diffraction pattern of the present invention is carried out by the known method described in "Phthalocyanine Compounds" by Moser and Thomas. Acid pasting methods are best chosen if possible. Here, the acid pasting method refers to a method in which a phthalocyanine compound is dissolved in sulfuric acid and then poured into water to be reprecipitated.

Although the obtained new crystals are sufficiently fine particles, they can also be used as finer particles by mechanical trituration.

Further, if necessary, it is also possible to use a grinding aid such as common salt or sulfur sulfate.

Equipment used during grinding includes a kneader, Banbury mixer, attritor, edge runner mill, roll mill, ball mill, and sand mill.

Examples include, but are not limited to, 5PEX mills, homo mixers, dispersers, agitators, jaw graphers, stamp mills, canter mills, and micronizers.

The charge generation layer of the present invention using a tin phthalocyanine compound having an x1 diffraction pattern showing a strong 1 peak at a specific Bragg angle 2θ is a uniform layer with high light absorption efficiency. An electrophotographic photoreceptor with few voids between the charge generation layer and the charge transfer layer, and between the charge generation layer and the undercoat layer or conductive substrate, which provides stable potential and prevents bright area potential from increasing during repeated use. characteristics, and a reduction in 1-image defects.

An electrophotographic photoreceptor with a rigid ring that satisfies many requirements can be obtained.

An n-type photoreceptor is fabricated by laminating an undercoat layer, a charge generation layer, and a charge transfer layer in this order on a conductive substrate. P-type photoreceptors are made by laminating a charge transfer layer and a charge generation layer in this order on an undercoat layer, or by dispersing and coating a charge generation agent and a charge transfer agent together with a suitable resin on the undercoat layer. There are things that have been done. If necessary, an overcoat layer may be provided on both photoreceptors for surface protection and prevention of toner filming.

The tin phthalocyanine compound of the present invention can be suitably used for all of the above-mentioned various photoreceptors. Also.

The charge generation layer can be obtained by dispersing and coating a tin phthalocyanine compound and a resin in an appropriate solvent.
It can also be used by dispersion coating without the resin.

It is also known that a charge generation layer can be obtained by vapor deposition.
The material obtained by the present invention has been processed down to the minute primary particles, and the crystals have been extremely well-organized using an appropriate solvent, so that impurities existing between the nine particles can be removed, making it possible to deposit the material very efficiently. It is also effective as a material for vapor deposition.

The photoreceptor is coated using a spin coater, applicator, spray coater, bar coater, dip coater, doctor blade, roller coater, curtain coater, or bead coater.

Drying is preferably carried out by heating at 40 to 200° C. for 10 minutes to 6 hours under stationary or blowing air conditions. After drying, the film is coated to a thickness of 0.01 to 5 microns, preferably 0.1 to 1 micron.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide variety of insulating resins.

It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably polyvinyl butyral,
Polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide resin, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, silicone resin , polystyrene, polyketone resin, polyvinyl chloride, vinyl chloride copolymer, polyvinyl acetal, polyacrylonitrile, phenol resin, melamine resin, casein, polyvinyl alcohol, polyvinylpyrrolidone, and other insulating resins. The resin contained in the charge generation layer is suitably 100% by weight or less, preferably 40% by weight or less. Further, these resins may be used alone or in combination of two or more.

The solvent for dissolving these resins varies depending on the type of resin, and it is preferable to select a solvent that does not affect the charge generation layer and undercoat layer, which will be described later, during coating.

Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin, monochlorobenzene, dichlorobenzene,
Ketones such as acetone, methyl ethyl ketone, and cyclohexanone, methanol, and ethanol.

Alcohols such as isopropanol, ethyl acetate.

Esters such as methyl cellosolve, carbon tetrachloride.

Chloroform, dichloromethane, dichloroethane.

Aliphatic halogenated hydrocarbons such as trichlorethylene, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether.

Amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and sulfoxides such as dimethylsulfoxide are used.

The charge transfer layer is formed by a charge transfer agent alone or by dissolving and dispersing it in a binder resin.The charge transfer agent used in the photoconductor is preferably the following formula (1) or (II). [■] and (II) may also be used in combination. heterocyclic residue,
Alternatively, R8 and R1 may form a heterocycle.) (In the formula, * R4, R, is a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group + R&I R?I R1 is a hydrogen atom or -NR,, (Rs) group, and n is 0 or 1.) Particularly preferable examples of general formula (n) include compounds in which R4゜Rs are both ethyl groups and +R&~R, l are hydrogen atoms, or Either R1-R1 is NCzHs (
CzHs).

In addition to these, inorganic materials such as selenium, selenium-tellurium amorphous silicon, and cadmium sulfide can also be used.

Further, charge transfer substances can be used alone or in combination of two or more types. Resins used for the charge transfer layer include silicone resin, ketone resin, polymethyl methacrylate,
Polyvinyl chloride, acrylic resin, polyarylate, polyester, polycarbonate.

Polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer.

Insulating resins such as polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. are used.

Coating methods include spin coater and applicator.

Spray coater, bar coater, dip coater.

The coating is carried out using a doctor blade, roller coater, curtain coater, or bead coater, and the film thickness after drying is preferably 5 to 50 microns, preferably 10 to 20 microns.

In addition to these layers, an undercoat layer can be provided on the conductive substrate for the purpose of preventing deterioration of chargeability, improving adhesion, and the like. As an undercoat layer, nylon 6, nylon 66, nylon 11. Nylon 610. Polyamides such as copolymerized nylon and alkoxymethylated nylon, casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymers, gelatin, polyurethane, polyvinyl butyral, and metal oxides such as aluminum oxide are used.

Further, the resin can be prepared by incorporating conductive and dielectric particles such as metal oxides such as zinc oxide and titanium oxide, silicon nitride, silicon carbide, and carbon Bragg.

The material of the present invention has absorption peaks at wavelengths of 800 m or more and 650 r+n+, and can be used as an electrophotographic photoreceptor in copying machines,
In addition to being used in printers, solar cells.

It is also suitable as an absorbing material for photoelectric conversion elements and optical disks.

(Example) Hereinafter, nine embodiments of the present invention will be specifically described.

In the examples, parts refer to 9 parts by weight.

Example 1 After heating reaction of 20.4 parts of phthalodinitrile and 10.4 parts of tin tetrachloride in 200 parts of quinoline at 220°C for 4 hours,
The solvent was removed by steam distillation. It is then purified with acetone and the sample is dried to give dichlorotin phthalocyanine (S n
20.3 parts of Cl z P c ) were obtained.

Two parts of this dichlorotin phthalocyanine are dissolved in portions in 40 parts of 98% sulfuric acid at 5°C, and the mixture is stirred for about 1 hour while maintaining the temperature below 5°C.

Subsequently, the sulfuric acid solution was placed in 400 parts of ice water with high speed stirring.

The crystals were slowly poured and the precipitated crystals were filtered. The crystals were washed with distilled water until no acid remained, purified with acetone, and dried to obtain 1.8 parts.

The X-ray diffraction diagram of the obtained dichlorotin phthalocyanine is shown in FIG. This dichlorotin phthalocyanine has a Bragg angle (2θ±0.2') of 8.6°, 12°2°, 1
It had strong peaks at positions of 4.9°, 17.4°, 19.4° and 27.6°.

Next, a method for producing an electrophotographic photoreceptor using this dichlorotin phthalocyanine as a charge generating agent will be described.

Copolymerized nylon (Amiran CM-8000 manufactured by Toshi) 10
was mixed with 190 parts of ethanol in a ball mill for 3 hours, and the dissolved coating liquid was applied with a wire bar onto a sheet of polyethylene terephthalate (PET) film with aluminum vapor-deposited, and then dried at 100°C for 1 hour. A sheet having a subbing layer with a thickness of 0.5 microns was obtained.

Two parts of dichlorotin phthalocyanine obtained in this example was added to TH
The mixture was dispersed in a ball mill for 6 hours with a resin solution prepared by dissolving 1 part of vinyl chloride-vinyl acetate copolymer resin (VMCH manufactured by Union Carbide) in 97 parts of F.

This dispersion was applied onto the undercoat layer and dried at 100°C for 1 hour to form a charge generation layer of 0.3 microns.

Next, as a charge transfer agent, 1 part of exemplified compound (1-a) of the compound of formula (1) and 1 part of polycarbonate resin (Panlite L-1250 manufactured by Kijin Kasei) were mixed and dissolved in 8 parts of methylene chloride. Coat this solution on the charge generation layer,
After drying at .degree. C. for 1 hour, a 15 micron charge transport layer was formed and electrophotographic properties were measured.

Example 2 A photoreceptor was prepared in the same manner as in Example 1, except that the exemplified compound (n-a) of formula (II) was used as a charge transfer agent, and its electrophotographic properties were measured.

The electrophotographic properties of the photoreceptor were measured by the following method.

Static mode 2. Corona charge is 1 at -5.2KV
Surface potential and 51. By irradiating with white light of UX or light adjusted to 800 parts of 1 μW, the charge amount is 1/2 and 11
White light half-exposure ffi anger degree (E
l/2 and E115). Also.

Evaluation of repetition characteristics is -5.2KV, corona linear velocity 12
Charged at 0mm/sec, left in the dark for 2 seconds, 5L
Changes in surface potential and sensitivity were measured repeatedly in the order of 3-second exposure using UX.

In addition, 2 spectral sensitivity was measured using an electrostatic charging test device.

After corona charging the photoreceptor to -5.4KV, 50
A 0W xenon lamp was used as the light source, and a monochromator (
(manufactured by Jovan Ipon) as monochromatic light, and the light attenuation during charging exposure was measured.

The results of electrophotographic properties are shown in Table 1.

Table 1 (Initial characteristics) (After 10,000 repetitions) From the results in Table 1, the photoreceptor of Example 1.2 exhibited high sensitivity characteristics both in the initial characteristics and even after 10,000 repetitions.

Example 3 On a PET film having an undercoat layer formed under the same conditions as Example 1, under a vacuum condition of 10-' Torr, 45
A charge generation layer having a thickness of 0.15 μm was obtained at 0°C. A charge transfer layer was formed thereon under the same conditions as in Example 1, and the electrophotographic properties were measured.

Table 3 From the results shown in Table 3, the photoreceptor of Example 3 exhibited high sensitivity characteristics both at the initial stage and after 10,000 repetitions. The sensitivities of the 9 dispersion and vapor deposition methods were almost the same.

Comparative Example 1 20.4 parts of phthalodinitrile and 10.4 parts of tin tetrachloride were heated and reacted in 200 parts of α-chloronaphthalene at 220° C. for 4 hours, then cooled and the solvent was removed by steam distillation. Next, hot suspension is carried out in methanol and N-methylpyrrolidone in this order, followed by filtration in that order. The filtrate was dried to obtain 18.6 parts of dichlorotin phthalocyanine.

The X-ray diffraction pattern of the obtained dichlorotin phthalocyanine is shown in FIG. Bragg angle (2θ±0.2°) of 8°4°, 13.8°, 22.4°, 28.2° and 30.0
The crystal had a strong peak at the 0 position and was completely different from the dichlorotin phthalocyanine of the present invention. Next, a photoreceptor was prepared using this dichlorotin phthalocyanine in the same manner as in Example 1, and its electrophotographic properties were measured.

Table 4 From the results shown in Table 4, the photoreceptor produced in Comparative Example 1 was significantly inferior in sensitivity than the photoreceptors of Examples 1 to 3.

〔Effect of the invention〕

With the present invention, in addition to excellent exposure sensitivity characteristics and wavelength characteristics,
Deterioration resistance properties during repeated use over long periods of time.

An electrophotographic photoreceptor having rigidity resistance of 1 and image stability could be obtained.

[Brief explanation of the drawing]

FIG. 1 is an X151 diffraction diagram of dichlorotin phthalocyanine produced in Example 1, and FIG. 2 is an X-ray diffraction diagram of dichlorotin phthalocyanine produced in Comparative Example 1.

Claims (1)

[Claims] 1. Bragg angle (2θ±0.2°) of 8.6°, 12
．． 2°, 14.9°, 17.4°, 19.4° and 2
An optical semiconductor material comprising a tin phthalocyanine compound having an X-ray diffraction diagram showing a strong peak at a position of 7.6°. 2. In an electrophotographic photoreceptor using a charge generating agent and a charge transfer agent on a conductive support, the charge generating agent is
Bragg angle (2θ±0.2°) of 8.6° and 12.2
°, 14.9 °, 17.4 °, 19.4 ° and 27.
An electrophotographic photoreceptor comprising a tin phthalocyanine compound having an X-ray diffraction diagram showing a strong peak at a 6° position. 3. In an electrophotographic photoreceptor comprising a charge generating agent and a charge transfer agent on a conductive support, the charge generating agent is a tin phthalocyanine compound according to claim 2, and the charge transfer agent is the following general formula [I] or [II]
An electrophotographic photoreceptor characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (R_1, R_2, or R_3 are alkyl groups, aralkyl groups, aryl groups, or heterocyclic residues that may have substituents, or R_2 and R_3 combine to form a heterocyclic group. (May form a ring.) ▲Mathematical formulas, chemical formulas, tables, etc.▼[II] (In the formula, R_4 and R_5 are hydrogen atoms, alkyl groups, alkoxy groups, or aryl groups, and R_6, R_7, and R_8 are hydrogen atoms. or -NR_4(R_5) group, n is 0
or 1. 4. The electrophotographic photoreceptor according to claims 2 and 3, which has an inorganic or organic subbing layer on a conductive support.