| 摘要 |
PURPOSE:To enhance sensitivity and printing resistance and to obtain a good prints free from background stains by forming on a conductive substrate a photosensitive layer composed of an electrostatic charge generating layer contg. a specified azo pigment and a charge transfer layer contg. a charge transfer material and an alkali-soluble resin. CONSTITUTION:The photosensitive layer 2 composed of two layers of the charge generating layer 3 contg. an azo pigment represented by the formula, (A) being a coupler residue, and the charge transfer layer 4 contg. a charge transfer material and an alkali-soluble resin. The layer 3 is essentially consisting of the azo pigment of the formula, but it is preferable to use a binder resin, such as an alkali-soluble novolak type phenol resin. A toner image 5 is obtaind by forming an elctrostatic latent image on such a photosensitive layer 2, developing it with a toner, and heat fixing the toner image 5. This is treated with an alkaline extracting soln. to disclose the hydrophilic surface of the substrate 1, leaving the image part coated with the oleophilic toner. When the original printing plate thus obtained is used for lithography, an oily ink attaches only to the image part, and a sharp prints free from stains can be obtained. |
