Mita Industrial Co., Ltd.

Nariaki Mutou

Eiichi Miyamoto

Tooru Nakazawa

Tatsuo Maeda

A stable .alpha.-type titanyl phthalocyanine composition including an .alpha.-type titanyl phthalocyanine and a metal-free phthalocyanine is disclosed having a wide range of absorption wavelengths and high in spectral sensitivity. The method for making the phthalocyanine composition is carried out by pigmenting a concentrated sulfuric acid solution containing at least titanyl phthalocyanine by an acid paste process. The concentrated sulfuric acid solution is poured into water to produce an .alpha.-type titanyl phthalocyanine composition which is stable to withstand the impact of aging. Also disclosed is an electrophotographic sensitive material which includes a sensitive layer having the .alpha.-type titanyl phthalocyanine composition superposed on an electroconductive substrate. This electrophotographic sensitive material excels in its charging property and its dark attenuation property and exhibits high sensitivity and low residual potential. The electrophotographic sensitive material having a sensitive layer comprising the .alpha.-type titanyl phthalocyanine composition and an electric charge transferring material can also be superposed on an electroconductive substrate. This electrophotographic photosensitive material exhibits an oxidation potential in the ranage of 0.45 to 0.65 eV, enjoys high sensitivity, and shows low residual potential.

.alpha.-type titanyl phthalocyanine composition, method for production

The first aspect of this invention resides in providing an .alpha.-type titanyl phthalocyanine composition comprising an .alpha.-type titanyl phthalocyanine and metal-free phthalocyanine. This .alpha.-type titanyl phthalocyanine composition is stable, wide in range of absorption wavelengths, and high in spectral sensitivity because it contains an .alpha.-type titanyl phthalocyanine in combination with metal-free phthalocyanine. The second aspect of this invention resides in providing a method for the production of an .alpha.-type titanyl phthalocyanine composition comprising an .alpha.-type titanyl phthalocyanine and a metal-free phthalocyanine, which method comprises pigmenting a concentrated sulfuric acid solution containing at least titanyl phthalocyanine by the acid paste process consisting in pouring said concentrated sulfuric acid solution into water. By this method, an .alpha.-type titanyl phthalocyanine composition stable to withstand the impact of aging can be easily produced.

There is disclosed an electrophotographic sensitive layer which is provided with a single-layer type sensitive layer containing a specific perylene type compound as an electric charge generating substance, a specific diamine derivative of the following general formula as an electric charge transferring substance, and a binding resin. ##STR1## wherein R.sup.5, R.sup.6, R.sup.7, and R.sup.8 independently stand for either a group of the general formula: ##STR2## or a group of the general formula: ##STR3##

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Daito, Japan

Nariaki Mutou