| 摘要 |
PURPOSE:To satisfactorily maintain the electrostatic charge of developer particles and to form a sharp image of a high density without generating fogging while satisfactorily maintaining the holding of a magnetic brush of the developer on a specific developing sleeve provided internally with a magnet by using the above-mentioned developing sleeve. CONSTITUTION:The sleeve 1 consists of a conductive sleeve base body 2 and a coated film 3 of a metal oxide particle/high-polymer resin dispersion. The metal oxide particles 4 have 3-100mum grain size, <=10<10>OMEGA-cm specific volume resistivity and positive electrostatic chargeability and are dispersed in the high-polymer resin dispersion medium. Projecting parts 6 and recesses 7 are formed in this coated film 3 and the roughness thereof exists in a 5-20mum range. The surface of the coated film is held electrically conducted to the sleeve base body 2 through the metal oxide particles 4 dispersed in the coated film. The magnet 12 for forming the magnetic brush is provided in the developing sleeve 1. The electrostatic charging of the one-component type magnetic developer is thereby effectively executed and the napping of the magnetic brush of the developer is effectively executed as well. In addition, the effective adjustment of the electrostatic charge potential of the toner and the effect of preventing the fogging by biasing are enabled as well. |
