| 摘要 |
PURPOSE:To improve the reproducibility of a low-contrast line image without spoiling the reproducibility of an allover black part, by coating the surface of a developing sleeve with a material which varies in conductivity with an electric field. CONSTITUTION:On a conductive cylinder made of aluminum, MgF2 is vapor- deposited to 500Angstrom to manufacture a developing sleeve 1. On the sleeve, a magnetic brush 5 is formed of a developer which uses conductive iron oxide powder as a carrier, and the magnetic brush is brought into contact with a photoreceptor 4 made of an aluminum pipe to measure conductivity between both sleeves by an applied voltage. As a result, the conductivity increases as the applied voltage rises and decreases extremely in a low electric field. The conductivity characteristics vary linearly with the applied voltage. As the surface coating material, SiO2 is usable instead of MgF2. |
