| 摘要 |
PURPOSE:To obtain a photoreceptor to be colored by irradiation of ultraviolet rays and to be decolored by heating or the like, and capable of being used repeatedly, by dispersing a fine powder of an ortho-niobate, a compound of niobium of rare earth elements having photochromism into a transparent film- forming polymer, and forming this dispersion layer on the surface of a substrate. CONSTITUTION:A fine powder of ortho-niobate, a rare earth compound, such as YNbO4 or EuNbO4 containing 0.01-0.1mol% PrNbO4, TbNbO4, or ErNbO4 based on the total composition is heated to 1,250-1,400 deg.C, and pulverized to 0.1-10mum size. This fine powder is dispersed into a transparent solution of a urethane or silicone type polymer, and the dispersion liquid is coated on a substrate, such as paper or synthetic resin film to form a 50-200mum thick photosensitive layer. This photoreceptor is colored from a pale color to a dark brown with ultraviolet rays, and retains this color for a long term. When it is irradiated with laser beams or heated to 100-200 deg.C, it returns to the initial color, and can be used repeatedly. |
