| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roll which hardly gives rise to an after-image phenomenon and a developing apparatus using the same. SOLUTION: A semiconductive roll (development roll) 12 includes an elastic semiconductor layer 2 which consists of an elastic material of 1x10<SP>2</SP>to 1x10<SP>7</SP>(Ωcm) in volume resistivityρ<SB>1</SB>, and a toner carrier layer 3 which is formed on the layer 2 and has the volume resistivityρ<SB>2</SB>satisfyingρ<SB>2</SB>/ρ<SB>1</SB><1,000. In addition, the surface roughness R of the toner carrier layer is 1 to 10μm in ten-point average roughness Rz stipulated in JIS (Japanese Industrial Standards) and satisfies the conditions 1Rz<d<5Rz when the thickness of the layer 3 is defined as (d). The developing apparatus uses such semiconductive roll. Preferably the layer 3 consists essentially of any one or more kinds selected from a urethane resin containing conductive powder, silicone resin, silicone denatured urethane resin, and fluororesin and the layer 2 consists of any one or more kinds among silicone rubber, polyurethane rubber and ethylene-propylene-diene rubber as a substrate surface. COPYRIGHT: (C)2004,JPO |
