| 摘要 |
PURPOSE:To prevent variation in image density due to a decrease in toner density by using such a developer that the product of the magnetism and coercive force of high-resistance magnetic toner is larger than or equal to the product of the magnetism and coercive force of magnetic carriers. CONSTITUTION:A photosensitive body 1 rotates as shown by an arrow and an electrostatic latent image is formed on its surface. A developing device 2 consists of a fixed magnet roll 3, a nonmagnetic sleeve 4 which rotates counterclockwise, and a doctor 7, and the developer 5 thrown in a hopper 6 is attracted to the roll 3 and conveyed through the rotation of the sleeve 4. The developer 5 controlled by the doctor 7 is napped by main magnetic poles N1 of the roll 3 and contacts the photosensitive body 1 to form the electrostatic latent image. The developer 5 uses a mixture of high-resistance magnetic toner and magnetic carriers and the product of the magnetism and coercive force of the high- resistance magnetic toner is larger than or equal to the product of the magnetism and coercive force of magnetic carriers. Thus, variation in picture density due to a decrease in toner density is prevented. |
