Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
1995-03-09
2001-07-31
Rodee, Christopher (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S056000, C430S059500
Reexamination Certificate
active
06268096
ABSTRACT:
FILED OF THE INVENTION
The present invention relates to a novel crystal of titanyl phthalocyanine useful as a photoconductive material, a photoconductive material comprising the same, and an electrophotographic photoreceptor using the same.
BACKGROUND OF THE INVENTION
Phthalocyanine compounds are useful as coatings, printing inks, catalysts or electronic materials. In recent years, they have been extensively studied particularly for their use as electrophotographic photoreceptor materials, optical recording materials and photoelectric conversion materials.
In general, phthalocyanine compounds are known to have several different crystal forms depending on the process of production or the process of treatment. The difference in crystal form is known to have a great influence on their photoelectric conversion characteristics. For example, known crystal forms of copper phthalocyanine compounds include &agr;-, &pgr;-, &khgr;-, &rgr;-, &ggr;- and &dgr;-forms as well as a stable &bgr;-form. It is known that these crystal forms are capable of mutual transformation by a mechanical strain, a sulfuric acid treatment, an organic solvent treatment, a heat treatment and the like as described, e.g., in U.S. Pat. Nos. 2,770,629, 3,160,635, 3,708,292, and 3,357,989. Further, a relationship between the crystal form of copper phthalocyanine and electrophotographic sensitivity is described in JP-A-50-38543 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”).
With respect to titanyl phthalocyanine, various crystal forms in relation to electrophotographic characteristics have been reported. For example, JP-A-62-67094 describes a stable &bgr;-form, JP-A-61-217050 describes an &agr;-form obtained by acid pasting or solvent treatment. Other crystal forms are disclosed in JP-A-63-366, JP-A-63-20365, JP-A-64-17066, and JP-A-1-153757.
However, any of the above-described titanyl phthalocyanine compounds proposed to date has poor crystal form stability against solvents and therefore, when dispersed and coated, cannot hold its crystal form for a long period of time.
Moreover, it is still unsatisfactory in photosensitivity and durability when used as a photosensitive material. That is, electrophotographic characteristics of titanyl phthalocyanine crystals are liable to variation depending on the diameter of primary particles, the specific surface area or shape of crystal grains, the absorbed water content, etc., thus making it difficult to obtain an electrophotographic photoreceptor having stable performance properties.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel titanyl phthalocyanine crystal which produces an electro-photographic photoreceptor having high photosensitivity and improved stability.
Another object of the present invention is to provide a photoconductive material comprising such a titanyl phthalocyanine crystal which has high sensitivity, improved stability, and prolonged durability.
A further object of the present invention is to provide an electrophotographic photoreceptor containing such a titanyl phthalocyanine crystal as a photoconductive material.
Other objects and effects of the present invention will be apparent from the following description.
As a result of extensive investigations, the inventors have found that crystal form stability of a titanyl phthalocyanine crystal showing a diffraction peak at a Bragg angle (2&thgr;±0.2°) of 27.3° can be improved by controlling the primary particle size within a specific range and specifying the shape of the crystal. The crystal having the thus improved stability holds its crystal form for a prolonged period of time even after being dispersed and coated. When used as a photoconductive material, it provides an electro-photographic photoreceptor having high sensitivity, improved stability, and prolonged durability. The present invention has thus been completed based on the above finding.
The present invention relates to a titanyl phthalocyanine crystal having a primary particle diameter ranging from 0.03 to 0.15 &mgr;m, showing a maximum X-ray diffraction peak at a Bragg angle (2&thgr;±0.2°) of 27.3°, having a ellipsoidal tabular form, and having a BET specific surface area of not less than 35 m
2
/g.
The present invention also relates to an electrophoto-graphic photoconductive material comprising the above-described titanyl phthalocyanine crystal.
The present invention further relates to an electrophoto-graphic photoreceptor comprising a support having thereon a photosensitive layer comprising a binder resin having dispersed therein the above-described titanyl phthalocyanine crystal, said photosensitive layer showing a maximum X-ray diffraction peak at a Bragg angle (2&thgr;±0.2°) of 27.3°.
REFERENCES:
patent: 2192704 (1940-03-01), Dahlen et al.
patent: 2770629 (1956-11-01), Eastes
patent: 3160635 (1964-12-01), Knudsen et al.
patent: 3357989 (1967-12-01), Byrne et al.
patent: 3708292 (1973-01-01), Brach et al.
patent: 4497741 (1985-02-01), Hölzle et al.
patent: 4499018 (1985-02-01), Doré et al.
patent: 4664997 (1987-05-01), Suzuki et al.
patent: 4728592 (1988-03-01), Ohaku et al.
patent: 4845209 (1989-07-01), Adam
patent: 4898799 (1990-02-01), Fujimaki et al.
patent: 4994339 (1991-02-01), Kinoshita et al.
patent: 5378569 (1995-01-01), Nukada et al.
patent: 48-724 (1973-01-01), None
patent: 51-109841 (1976-10-01), None
patent: 61-239248 (1986-10-01), None
National Bureau of Standards (1950), Tables for Conversion of X-ray Diffraction Angles to Interplanar Spacings. Washington, DC: USGPO.
Klug, Harold P. and Leory E. Alexander (1974), X-ray Diffraction Procedures. New York: John Wiley & Sons. p. 69.
Cullity, B. D. (1978, Elements of X-ray Diffraction. Reading, Mass.: Addison-Wesley Publishing Company, Inc. pp. 3, 4 & 21.
Stout et al., “Practice of X-Ray Structural Analysis”, Tokyo Kagaku Dojin, pp. 11-13.
Hoshizaki Taketoshi
Komori Yumiko
Nishikawa Masayuki
Nukada Hidemi
Ojima Fumio
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Fuji Xerox Co. LTD
Rodee Christopher
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