| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of an uneven density and fog and deterioration of image density over a long period by incorporating a polyester resin having an acid value in a specified range and an vinylic resin having anionic functional groups. SOLUTION: The binder carrier comprises at least a magnetic powder and a polyester resin having an acid value of 17-55 KOH mg/g, preferably, 19-50, further preferably, 30-45 KOH mg/g, and the vinylic resin having the anionic functional groups, which are not especially limited, so long as they are anionic functional groups, for example, sulfonic and carboxylic group and hydroxy group and the like can be enumerated, and preferably, sulfonic acid group is used. As the toner, positively or negatively chargeable toner may be used in accordance with a charge controller to be used or a carrier to be used, but the positively chargeable toner is preferred. |
