| 摘要 |
PROBLEM TO BE SOLVED: To improve the physical strength and to restrict fall of an image part, damage of a non-image part, elusion of the oxide film and residual color in the photosensitive layer by respectively setting the number of holes of an oxide film surface and the number of holes of an interface between the oxide film and aluminum at a specified number. SOLUTION: The number of holes of an oxide film surface is set at 400-700 pieces/μm<2> , and the number of holes in an interface between the oxide film and aluminum is set at 700-1500 pieces/μm<2> . As a method of forming a porous oxide film of low density of 400-700 pieces/μm<2> a processing vessel 3 for positive electrode oxidization is divided into plural parts to interrupt the electrode reaction on the way, and temperature rise is thereby prevented so as to prevent the generation of yellowing even at the relatively high voltage. The number of holes can be adjusted in response to a purpose, and liquid temperature can be adjusted per each processing vessel by dividing the vessel. A desirable number of dividing is 2-20, and for dividing, plural processing vessel 3 are arranged, and each processing vessel is desirably provided with a power source to fluctuate the dividing condition. |
