JPH02214867A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance electric chargeability, sensitivity, dark decay resistance, and resistance to rise of residual potential, and the like by using a specified oxytitanium phthalocyanine as a charge generating material and a specified compound as a charge transfer material. CONSTITUTION:The oxytitanium phthalocyanine to be used as the charge gener ating material has a main diffraction peak at the Bragg angle (2theta+ or -0.2 deg.) of 27.3 deg. in the X-ray diffraction spectra, and the compound to be used as the charge transfer material is represented by formula I in which each of R<1>, R<3>, R<5>, and R<6> is H, alkyl, alkoxy; each of R<2> and R<4> is alkyl, aryl, aralkyl, optionally substituted phenyl or naphthyl; and n is 0 or 1, thus permitting the obtained electrophotographic sensitive body to be high in sensitivity and electric chargea bility, low in residual potential, small in variance in the characteristics due to repeated uses, and good in stability of chargeability and durability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor having high sensitivity and excellent characteristics from the visible light region to the near-infrared wavelength region.

[Conventional technology and its problems]

Conventionally, photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors.

Further, research on the use of organic photoconductive materials, typified by polyvinyl carbazole, in photosensitive layers of electrophotographic photoreceptors has progressed, and some of them have been put into practical use.

Organic photoconductive substances have advantages over inorganic materials, such as being lightweight, easy to form a film, easy to manufacture photoreceptors, and materials that do not cause any damage. .

In recent years, laser beam printers (LBPs), which use laser light as a light source instead of conventional white light and have the advantages of high speed, high image quality, and non-impact, have become widely popular along with advances in information processing systems. There is a demand for the development of materials that can withstand these demands.

In particular, among laser beams, semiconductor lasers, which have seen remarkable technological progress and have been increasingly applied to compact disks, optical disks, etc., have been actively applied in the printer field as a compact and highly reliable light source material.

In this case, since the wavelength of the light source is around g 00 nm, there is a strong desire to develop a photoreceptor that is highly sensitive to long wavelength light around g 00 nm.

JP-A-591Iqsll is a material that meets this purpose.
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9go67, 63-/9gOAg, 63-2109
Various oxytitanium phthalocyanines are known, including the materials described in No. '72 and Otsu No. 3-27gVAg, each of which has a crystal type suitable as a material for an electrophotographic photoreceptor. However, there has been a demand for an electrophotographic photoreceptor that is highly sensitive to longer wavelength light and has other good electrical properties.

As a result of intensive study on electrophotographic photoreceptors using oxytitanium phthalocyanines, the present inventors found that the Bragg angle (,2θ10,,2°
) If a photoreceptor is made using oxytitanium phthalocyanine, which exhibits a main diffraction peak at 3°, as a charge-generating material, and a specific compound as a charge-transporting material, the desired purpose can be achieved, and the chargeability, sensitivity, and darkness can be improved. The present inventors have discovered that it is possible to provide a well-balanced electrophotographic photoreceptor with good attenuation, residual potential, etc., and have completed the present invention.

[Means to solve the problem]

That is, the gist of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer containing a charge-generating material and a charge-transporting material on a conductive support. λθ±0.2°)s
7: Oxytitanium phthalocyanine exhibiting a main diffraction peak at R4 represents an alkyl group, an allyl group, an aralkyl group, a phenyl group, a substituted phenyl group, or a naphthyl group, and n represents O or the number of /. Exists in the body.

(for production) The present invention will be explained in detail below.

Among the materials forming the electrophotographic photoreceptor of the present invention, oxytitanium phthalocyanine used as a charge generating material has a Bragg angle (λ
It has a main diffraction peak at 27.3° of θ10, 2°). In the present invention, the "main diffraction peak" refers to the peak with the strongest (highest) intensity in the X-ray diffraction spectrum.

Examples of powder X-ray spectra of the oxytitanium phthalocyanine used are shown in FIGS. 1 and 2. As shown in the figure, the main diffraction peak is the Bragg angle (λθ 00.2') core and 3° diffraction peak, and other peaks vary depending on detailed conditions, but the The intensity (comparison of peak heights) of the peak is also S
0% or less is preferable as an electrophotographic photoreceptor from the viewpoint of chargeability, sensitivity, etc.

Although the method for producing oxytitanium phthalocyanine used in the present invention is not particularly limited, it is produced, for example, by the following method.

■ JP-A No. 2003-120002 λ-t, qoql I Publication Production Example/method for producing CID type crystals described therein. That is, orthophthalodinitrile and a titanium chloride are reacted by heating in an inert organic solvent, and then hydrolyzed.

■ Various crystalline forms of oxytitanium phthalocyanine are directly dissolved in sulfuric acid or represented by the formula R5O3H (wherein R represents an aliphatic or aromatic residue which may have a substituent) in an organic acid solvent. heat treatment with a sulfonated compound,
In some cases, the mixture is then heat-treated with a mixed solvent of a water-insoluble organic solvent and water.

■ If desired, preliminarily dissolve in concentrated sulfuric acid and release into drained water, or make the paint amorphous by a known method such as mechanical grinding using a ball mill, sand grind mill, etc., and then heat-treat with the above sulfonated product. or heat-treated in a mixed solvent of a water-insoluble organic solvent and water.

■ In the case of the treatment with the above-mentioned sulfonated product, instead of heat treatment, mechanical grinding methods such as paint shaker ball mill, sand grind mill, etc. can be used in combination.

As the charge transport material, a compound represented by the above-mentioned general formula (I) is used.

In the general formula (I), R1, R3, R5 and R6 represent a hydrogen atom; mainly a lower alkyl group such as a methyl group, an ethyl group, a propyl group, or an alkoxy group such as a methoxy group or an ethoxy group; They may be the same or different from each other. Particularly preferred are a hydrogen atom, a methyl group, and the like.

R2 and R4 are mainly lower alkyl groups such as methyl group and ethyl group; Allyl group: aralkyl group such as benzyl group and phenethyl group; Phenyl group: substituted phenyl group such as methylphenyl group, halophenyl group, and methoxyphenyl group. or represents a naphthyl group, which may be the same or different from each other. Preferred are phenyl group, methylphenyl group, etc.

Further, n represents 0 or the number of l.

To explain the photoreceptor of the present invention in more detail, the photoreceptor of the present invention contains a charge generating material and a charge transporting material in a photosensitive layer formed on a conductive support. Specifically, in the photoreceptor of the present invention, a charge generating material is usually deposited directly or coated as a dispersion with a binder to form a charge generating layer, and then cast from an organic solvent solution or dissolved/dispersed with a binder. This is a laminated photoreceptor in which a charge transport layer containing a charge transport material is formed by liquid coating.
The stacking order of the charge generation layer and the charge transport layer may be reversed.

Alternatively, the photoreceptor of the present invention may be a single-layer type photoreceptor in which a charge generating material and a charge transporting material are dispersed and dissolved in a binder and coated on a conductive support.

In addition to these, intermediate layers such as adhesive layers and blocking layers, and layers for improving electrical properties and mechanical properties such as protective layers may be provided.

As the conductive support, any of those employed in well-known electrophotographic photoreceptors can be used.

Specific examples include metal drums and sheets made of aluminum, stainless steel, copper, etc., and laminates and vapor deposits of these metal foils.

Further examples include metal powder, carbon blank, plastic film, plastic drum, paper, paper tube, etc., which are coated with a conductive substance such as a polymer electrolyte together with a suitable binder and treated for conductivity. Examples include plastic sheets and drums that contain conductive substances such as carbon black, carbon fiber, etc., and are made conductive.

Also included are plastic films and belts treated with conductive metal oxides such as tin oxide and indium oxide. The charge generation layer formed on these conductive supports is
It is obtained by coating and drying a coating solution obtained by dissolving or dispersing the oxytitanium phthalocyanine particles of the present invention, a binder polymer, and, if necessary, an organic photoconductive compound, a dye, an electron-withdrawing compound, etc. in a solvent. Examples of binders include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic esters, methacrylic esters, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane, and cellulose ester. , cellulose ether, phenoxy resin, silicone resin, epoxy resin and the like. The ratio of oxytitanium phthalocyanine to binder polymer is
Although there are no particular limitations, generally 5 to 300 parts by weight, preferably 20 to 300 parts by weight of the binder polymer is used per 100 parts by weight of oxytitanium phthalocyanine.

The thickness of the charge generation layer is 0.03~! rμm, preferably 0.7-2 μm.

The charge transport layer into which charge carriers are injected from the charge generation layer contains a charge transport material that has high carrier injection efficiency and high carrier transfer efficiency.

A binder polymer may be used in the charge transport layer if necessary. As the binder polymer, it is preferable to use a polymer that has good compatibility with the above-mentioned charge transport material and that does not cause the charge transport material to crystallize or undergo phase separation after coating film formation. Examples thereof include styrene, vinyl acetate, and chloride. vinyl,
Polymers and copolymers of vinyl compounds such as acrylic esters, methacrylic esters, butadiene, polyvinyl acecool, polycarbonate, polyesters, polysulfones, polyphenylene oxides, polyurethanes, cellulose esters, cellulose ethers, phenoxy resins, silicone resins, Examples include epoxy resin.

The amount of binder polymer used is usually the charge transport material io
30 to 3000 parts by weight, preferably 70 parts by weight
-1000 parts by weight.

In addition to the above, various additives can be used in the charge transport layer to improve the mechanical strength and durability of the coating film.

Examples of such additives include well-known plasticizers, various stabilizers, flow agents, crosslinking agents, and the like.

[Effects of the Invention] The electrophotographic photoreceptor of the present invention obtained in this manner has high sensitivity, low residual potential, high charging property, and small fluctuations due to repetition, and particularly stable charging that affects image density. Since it has good properties, it can be used as a highly durable photoreceptor.

7 again! ;0-g! ; Since the sensitivity is high in the Onm region, it is particularly suitable for photoconductors for semiconductor laser printers.

〔Example〕

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

Production example/phthalodinitrile 97. ! ; jJ is α-chloronaphthalene 7! ; 0rn13dpVC was added, and then 2.2ml of titanium tetrachloride was added dropwise under a nitrogen atmosphere. After the dropwise addition, the temperature was raised, and the mixture was reacted at 200-2.10°C for 3 hours with stirring, then allowed to cool, filtered while hot at 100-2.30°C, and heated to 100°C.
Washed with 200 rnl of α-chloronaphthalene heated to . The obtained crude cake was mixed with α-chloronaphthalene 300
m1. Next, suspension washing was carried out with 300 ml of methanol at room temperature, and then hot washing was carried out several times with 00 ml of methanol for 7 hours.The obtained cake was suspended in 700 ml of water, and hot washing was carried out for - hours. Ta.

The pH of the furnace solution was below . Hot water washing was repeated until the pH of the furnace solution reached 4 to 4.

The X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine is shown in FIG.

As is clear from Figure 1, the Bragg angle (λθ±0.2°
) shows a sharp peak at 27.3°, but the other peaks are relatively broad.

Production Example: β-type oxytitanium phthalocyanine qog having the X-ray diffraction spectrum shown in Figure 3 was mixed with qg% concentrated sulfuric acid 11
The mixture was dissolved in 0.0 liters of medium and stirred in a water bath for 3 hours.

Then, a concentrated sulfuric acid solution was added dropwise to ice water/A73 over 30 minutes to make it sufficiently uniform, and then filtered. Thereafter, the obtained precipitate was suspended and washed with an aqueous sodium acetate solution to neutralize it.
Next, a neutral wet cake iiog was obtained by washing with water suspension and filtration.

Furthermore, the obtained wet cake gsg is water? 70 rn/ml, 7 ml of ortho-dichlorobenzene was added, and the mixture was stirred at a temperature of 60° C. for 7 hours.

The reaction solution was decanted to remove most of the water-orthodichlorobenzene, and then methanol g '00 rn
The mixture was stirred at a temperature of 0° C. for 1 hour, and then filtered and dried in a conventional manner to obtain blue oxytitanium phthalocyanine/gg.

The X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine is shown in FIG.

As is clear from Figure 2, the peak of the X-ray diffraction spectrum of the obtained oxytitanium phthalocyanine is very similar to the peak shape of Figure 1 shown in Production Example/, and the peak is at the Bragg angle (λθ〇, s''). It shows a sharp peak at 27.3°, but other pics have relatively wide peaks.

Example/Production Example/Oxytitanium phthalocyanine 0 produced in
．． q g, 0.2 g of polyvinyl butyral was dispersed with a sand grinder along with 30 g of methoxygoomethyl-pentason, and this dispersion was dried using a film applicator on the aluminum vapor deposited layer deposited on the polyester film. It was coated to a thickness of 0.3 g/7712 and dried to form a charge generation layer.

On this charge generation layer, N, N'-diphenyl-N, N
'-C(J-methylphenyl)-benzidine 7θ part, polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., Kneepilon E
-+2000) 100 parts of a charge transport layer having a film thickness of 7 μm was laminated to obtain an electrophotographic photoreceptor having a laminated type photosensitive layer.

The half-decreased exposure (E/) is used as the sensitivity of this photoreceptor using an electrostatic copying paper tester (Model SP-112g manufactured by Kawaguchi Electric Seisakusho).
It was measured by That is, in the dark, the corona current is SOμ
The photoreceptor is negatively charged by corona discharge with an applied voltage set to be A, and then exposed to white light with an illuminance of jlux. When I asked for 0.
It was 271ux-sec.

The charged voltage (initial surface potential) of the photoreceptor at this time was 3 g3V, and the surface potential (residual potential) after 70 seconds of exposure was -9V.

Example 3 The same procedure as Example 1 was performed except that the oxytitanium phthalocyanine produced in Production Example 2 was used instead of the oxytitanium phthalocyanine used in Example 2. The measured half-reduction exposure (E) is 0. /gluX-8
It was ec.

Example 3 Below, N, N'-diphenyl N, used in Example/
A photoreceptor was prepared in the same manner as in Example/, using the arylamine shown below in place of N'-di(3-methylphenyl)-benzidine, and the sensitivity was measured in the same manner as in Example/. did.

The results are summarized in the table below.

Kawayu 9- Comparative Example Example/In N, N'-diphenyl-N, N'
-di(3-methylphenyl)-N instead of benzidine
-Methyl-carbazole-3-aldehyde-diphenylhydrazone was carried out in exactly the same manner as in Example/, and the measured half-life exposure amount (E) was o, 701ux.
-sec.

[Brief explanation of the drawing]

FIGS. 1 and 2 are X-ray diffraction spectra of oxytitanium phthalocyanine used in the present invention. Figure 3 shows
This is an X-ray diffraction spectrum of β-type oxytitanium phthalocyanine used in Production Example.

Claims (1)

[Scope of Claims] A photoreceptor having a photosensitive layer containing a charge-generating material and a charge-transporting material on a conductive support, in which the charge-generating material has a Bragg angle (2θ±) in its X-ray diffraction spectrum.
0.2゜) Using oxytitanium phthalocyanine which shows a main diffraction peak at 27.3゜, the following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (in the formula , R^1, R^3, R^5 and R^6 represent a hydrogen atom, an alkyl group or an alkoxy group, and R^2 and R^4 represent an alkyl group, an allyl group, an aralkyl group, a phenyl group, a substituted phenyl group. or a naphthyl group, and n represents a number of 0 or 1.