| 摘要 |
PURPOSE:To prevent toner used for the preceeding development from being scratched off at the succeeding development when plural electrostatic images formed on the same surface of a photosensitive element are developed successively by different developers by making the surface of the photosensitive element coarse. CONSTITUTION:The surface of a photosensitive element 1 is made coarse. When negative red toner 2 is adsorbed into a positive polar latent image on the photosensitive element 1 for example, black development is performed by a magnetic brush of a carrier 3 for black toner 4. To prevent the red toner 2 from the influence of the force F given from the black toner 4, frictional force muFs to be acted should be F or more. In order to satisfy said condition, minute recessed grooves 5 for example are formed on the surface of the photosensitive element 1 in the direction of axial line, so that the coarseness of the surface is increased and the coefficient of friction mu is increased. The groove 5 is a recessed one with the average depth of 1.5mum and the average pitch of 15mum. |
