JPH06289628A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide a high sensitivity, excellent residual potential and electrostatic chargeability by incorporating water of the weight equal to or above the weight of an oxytitanium phthalocyanine crystal into a dispersion medium at the time of subjecting this crystal to a dispersion treatment in this dispersion medium. CONSTITUTION:A charge generating layer is formed by using a dispersion prepd. by subjecting the oxytitanium phthalocyanine crystal having the Bragg angle (2theta) of its X-ray diffraction spectra exhibiting a distinct diffraction peak at (27.3+ or -0.2) deg. to the dispersion treatment in the dispersion medium contg. the water of the weight equal to or above the weight of the crystal in the process for production of the electrophotographic sensitive body constituted by having a photosensitive layer on a conductive substrate. The dispersion is, therefore, prepd. without changing the crystal type of the oxytitanium phthalocyanine. The oxytitanium phthalocyanine to be used here is easily synthesized from, for example, phthalonitrile and titanium tetrachloride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photosensitive member using a crystal of oxytitanium phthalocyanine having a specific crystal type as a charge generating agent.

[0002]

2. Description of the Related Art Conventionally, phthalocyanine compounds have been used in electrophotographic photoreceptors.

In particular, some have been reported to have absorption peaks in the long wavelength region of 700 nm or more, and show high sensitivity in the near infrared region of semiconductor lasers depending on the type of central metal and crystal type. The research and development is actively done.

For example, there are various crystal types of oxytitanium phthalocyanine, and there is a large difference in chargeability, dark decay, sensitivity, etc. due to the difference in the crystal types.
59-49544, JP-A-59-166959, etc.

As a result of detailed examination of these crystal forms, the present inventors found that the Bragg angle (2θ) was (27.
It was found that oxytitanium phthalocyanine showing a clear diffraction peak at 3 ± 0.2) ° has very good sensitivity and has excellent characteristics.

[0006]

However, oxytitanium phthalocyanine, whose Bragg angle (2θ) shows a clear diffraction peak at (27.3 ± 0.2) °, is not a stable crystalline type and is applied to the charge generation layer. It was found that when the dispersion liquid of (1) was prepared, it was likely to change to another more stable crystal form depending on the dispersion conditions, and good characteristics such as sensitivity were impaired.

[0007]

[Means for Solving the Problems] Therefore, while maintaining the crystal form of such oxytitanium phthalocyanine,
As a result of studying the dispersion conditions for creating a stable dispersion liquid, when the dispersion treatment is carried out in the dispersion medium, by weight, by containing water in an amount equal to or more than the oxytitanium phthalocyanine crystals in the dispersion medium, The inventors have found that a dispersion liquid can be prepared while maintaining the crystal form even if other dispersion conditions are changed to some extent, and the present invention has been completed.

[0008]

That is, the present invention is a method for producing an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the X-ray diffraction spectrum has a Bragg angle (2θ) of (27.3
A charge generation layer was prepared by dispersing a crystal of oxytitanium phthalocyanine showing a clear diffraction peak at ± 0.2) ° in a dispersion medium containing water in an amount equal to or more than the weight of the crystal. And a dispersion liquid can be prepared by the method of the present invention without changing the crystal form of oxytitanyl phthalocyanine. Further, the electrophotographic photosensitive member obtained by the present invention exhibits extremely high sensitivity and exhibits favorable characteristics such as residual potential and chargeability.

[0009]

EXAMPLES The oxytitanium phthalocyanine used in the present invention can be easily synthesized from, for example, phthalonitrile and titanium tetrachloride.

That is, phthalonitrile and titanium tetrachloride were mixed with each other in an inert solvent such as 1-chloronaphthalene to give 20
Heat to 0-220 ℃ to react. The dichlorotitanium phthalocyanine thus obtained is filtered off and washed with the solvent used for the reaction while hot to remove impurities and unreacted substances. Further, after washing with alcohols such as methanol, hydrolysis is performed to obtain oxytitanium phthalocyanine. The oxytitanium phthalocyanine thus obtained is suspended in water after being made amorphous by, for example, an acid paste method, and an aromatic solvent is added and heat-treated,
The Bragg angle (2θ) of the X-ray diffraction spectrum is (2
A crystal of oxytitanium phthalocyanine having a main diffraction peak at 7.3 ± 0.2) ° can be obtained. Of course, it goes without saying that crystals of oxytitanium phthalocyanine having a main diffraction peak at (27.3 ± 0.2) ° can also be obtained by other methods.

Next, when the crystalline oxytitanium phthalocyanine is dispersed in a dispersion medium, the dispersion medium is mixed with water in an amount equal to or more than the weight of the oxytitanium phthalocyanine crystal. The obtained dispersion liquid is used to prepare a coating liquid for forming the charge generation layer.

As the dispersion medium, various solvents can be used as long as they are mixed with water and do not change the crystal form of oxytitanium phthalocyanine. For example, tetrahydrofuran, dioxane, acetone, ethanol, propanol and the like can be used alone or in combination.

The binder resin may be added to the dispersion medium in advance, or may be added after dispersion. The binder resin used may be any resin soluble in the dispersion medium, and examples thereof include polyvinyl butyral resin, polyester resin, and phenoxy resin.

As a method for dispersing the crystals of oxytitanium phthalocyanine, known methods such as a ball mill and a sand grind mill can be used.

The proportion of oxytitanium phthalocyanine and binder resin is not particularly limited, but in general resin 1
Oxytitanium phthalocyanine is added to 00 parts by weight.
Used in the range of 20 to 300 parts by weight. In order to improve the characteristics, various electron-withdrawing compounds or electron-donating compounds can be added to the dispersion liquid according to a conventional method, if necessary.

Using the dispersion liquid thus obtained,
A photosensitive layer is formed on the conductive support. As the photosensitive layer,
A charge generation layer formed by using the above dispersion liquid, a charge transport layer formed thereon, or a charge generation layer formed by using the above dispersion liquid on the charge transport layer, or the above dispersion liquid It is possible to use either one of a single-layer structure formed by only one.

When the charge transport layer is provided, examples of the charge transport agent used include heterocyclic compounds such as oxazole, oxadiazole and pyrazoline, hydrazone compounds, stilbene compounds and various derivatives of these compounds. Examples of the binder resin used with these charge transport agents include polyester,
Examples include various resins such as polycarbonate, polysulfone, and polymethylmethacrylate.

As the conductive support, an aluminum plate,
Examples thereof include an aluminum cylinder, an aluminum foil, and a plastic film provided with a thin film or foil of a conductive metal such as aluminum on the surface.

A commonly used known intermediate layer may be provided between the conductive support and the photosensitive layer. As the intermediate layer, for example, an inorganic layer such as an aluminum anodic oxide coating or an organic layer such as polyvinyl alcohol, polyurethane or polyamide is used.

The present invention will be specifically described below with reference to production examples and examples. (Production Example 1) 100 gr of phthalonitrile was added to 770 ml of 1-chloronaphthalene, and 24 ml of titanium tetrachloride was added dropwise with stirring under a nitrogen atmosphere. After that, raise the temperature to 200 ~
After reacting at 220 ° C for 3 hours, the mixture was allowed to cool, filtered while hot at 130 ° C, and washed with 200 ml of 1-chloronaphthalene at the same temperature. Then, it was washed with methanol until the filtrate became colorless.

The dichlorotitanium phthalocyanine obtained was subjected to a thermal suspension treatment (80 ° C., 1 hour), and the pH of the filtrate was adjusted to 5
This hot suspension treatment was repeated until ~ 7.

After drying the obtained oxytitanium phthalocyanine, its 20 gr was gradually added to 400 ml of sulfuric acid at 5 to 10 ° C., stirred at the same temperature for 2 hours and filtered, and the filtrate was poured into 5 L of water. Added The resulting precipitate was filtered off and washed thoroughly with distilled water until the filtrate showed no acidity. The obtained oxytitanium phthalocyanine was added to water 200
It was put in a suspension of 50 ml of chlorobenzene and heated at 80 ° C. for 3 hours.

The X-ray diffraction spectrum of the oxytitanium phthalocyanine thus obtained is shown in FIG. As shown in Fig. 1, the Bragg angle (2θ) is (27.3 ±
It has a clear peak at 0.2) °.

(Example 1) Polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., trade name S-REC BL- in a mixed solvent consisting of 475 parts by weight of tetrahydrofuran and 15 parts by weight of water)
1) 5 parts by weight were dissolved, and then 5 parts by weight of oxytitanium phthalocyanine prepared in Preparation Example 1 was added to this solution. Then, it was pulverized by a sand grind mill for 10 hours and finely divided.

Oxytitanium phthalocyanine was separated from the thus obtained dispersion liquid by a centrifugation method to obtain sample A. This X-ray diffraction spectrum is shown in FIG.
No change in crystal form is observed.

Next, by using the dispersion liquid obtained above by dip coating on an aluminum plate, the film thickness after drying is 0.1 μm.
It was provided so that

Next, on this charge generation layer, 50 parts by weight of a butadiene compound represented by the following (Chemical formula 1) and 50 parts by weight of a polycarbonate resin (Novalex 7030A, trade name, manufactured by Mitsubishi Kasei Co., Ltd.) were added to dichloromethane 350. The solution dissolved in parts by weight is also applied by dip coating to obtain a film thickness after drying.
The charge transport layer was provided so as to have a thickness of 20 μm.

[0028]

[Chemical 1]

As the initial electrical characteristics of this photosensitive member, the charging potential, the half-exposure amount and the residual potential were measured by an electrostatic copying paper tester EPA-8100 manufactured by Kawaguchi Electric Co., Ltd.

That is, the charging potential V when the photoreceptor is charged by corona discharge with a corona current of -30 μA in the dark.
Then, white light having an illuminance of 2 lux on the surface of the photoconductor was irradiated, and the exposure amount E1 / 5 required for reducing the surface potential to ⅕V0 and the residual potential Vr 4 seconds after the exposure were measured. The results are shown in (Table 1), and it can be seen that high sensitivity is exhibited.

[0031]

[Table 1]

Comparative Example 1 Sample B and a photoconductor were prepared in the same manner as in Example 1 except that 490 parts by weight of tetrahydrofuran was used alone as the dispersion solvent in place of the tetrahydrofuran-water system. The X-ray diffraction spectrum of sample B is shown in FIG. 3, and it can be seen that the spectrum pattern has changed and the crystal form has changed.

Next, the measurement results of the electrical characteristics are shown in (Table 1). It can be seen that the sensitivity is lower and the residual potential is higher than in Example 1.

[0034]

As described above, the method for producing the electrophotographic photoreceptor of the present invention has been described in detail. The electrophotographic photoreceptor obtained by the production method of the present invention exhibits extremely high sensitivity, residual potential, It was extremely excellent in chargeability and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing an X-ray diffraction spectrum of oxytitanium phthalocyanine obtained in Production Example 1.

FIG. 2 is a diagram showing an X-ray diffraction spectrum of Sample A obtained in Example 1 of the present invention.

FIG. 3 is a diagram showing an X-ray diffraction spectrum of Sample B obtained in Comparative Example 1.

Claims (1)

[Claims] 1. A method for producing an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the X-ray diffraction spectrum has a Bragg angle (2θ) of (27.3 ± 0.2) °. An electron characterized by forming a charge generation layer using a dispersion liquid obtained by dispersing a crystal of oxytitanium phthalocyanine showing a diffraction peak in a dispersion medium containing water in an amount equal to or more than the weight of the crystal. Manufacturing method of photographic photoreceptor.