| 摘要 |
PROBLEM TO BE SOLVED: To prevent a high temperature offset of toner in color image formation obtained by superposing and thermally fixing the toner having a plurality of colors. SOLUTION: In heat fixing, the toner having four colors of yellow, magenta, cyan and black is superposed and transferred sequentially on a transfer material 6, and the yellow (Y) toner 13Y is toner facing the fixing surface of a heating roller 8a. The black (BK) toner 13BK directly adheres to the transfer material 6, and does not face the fixing surface. The external additive isolation rate of the yellow toner 13Y being the toner facing the fixing surface is larger than the external additive isolation rates of the toner 13M, 13C and 13BK of other colors, and is set to the maximum. Thereby, many isolation external additives of the toner 13Y are present between the toner 13Y and the fixing surface, which improves release properties of toner and prevents the high temperature offset of toner. COPYRIGHT: (C)2004,JPO |
