| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller in which charging failure of toner is prevented to reduce the amount of consumption due to fogging, its manufacturing method, a developing device including the developing roller, and an image forming apparatus including the same. SOLUTION: In the developing roller, a plurality of first grooves 21 and a plurality of second grooves 22 intersecting the same are formed. The cross section of each of the first grooves 21 and the second grooves 22 forms a U shape. A protruded part 3 is formed in a region surrounded by the first grooves 21 and the second grooves 22. A plurality of micro protrusions 32 are formed on a top surface 31 of the protruded part 3. R<SB>0</SB>is 0.5 to 2 times the mean particle size of toner T particles, wherein R<SB>0</SB>denotes the surface roughness Rz of the top surface 31. D<SB>1</SB>and D<SB>2</SB>are each 0.5 to 2 times the mean particle size of the toner T particles, and the relations R<D<SB>1</SB>and R<D<SB>2</SB>are satisfied, wherein D<SB>1</SB>denotes the distance from the average line of a roughness curve of the surface roughness R<SB>0</SB>to the maximum depth part 213 of the first grooves 21, and D<SB>2</SB>denotes the distance from the average line of the roughness curve of the surface roughness R<SB>0</SB>to the maximum depth part of the second groove 22. COPYRIGHT: (C)2008,JPO&INPIT |
