| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller which has satisfactory deformation characteristics free from adverse effect of its deformation on images and also has excellent physical properties in which other faults are overcome. SOLUTION: In a one-component contact developing device for use in electrophotography, the developing roller which carries developer on its surface and comes into contact with an image forming body, thereby rendering a latent image on the image forming body visible is a roller composed of a satisfactorily conductive metal core in its center and a single or multi-layer including a conductive elastic layer. Further, the maximum radius x mm of the deformed portion of the developing roller formed when pressure is exerted to its surface towards the roller center with a hard presser having a diameter ofϕ0.7 to 1 mm satisfies the conditions of 1.75a≤x≤√(3RR<SP>2</SP>-2Rr-r<SP>2</SP>)/2 relative to an arbitrary amount a of indent with a depth of 1 to 2 mm, wherein R is the radius of the roller and r is the radius of the metal core. COPYRIGHT: (C)2005,JPO&NCIPI |
