| 摘要 |
PROBLEM TO BE SOLVED: To provide an image of high quality free from fog or dust by using a toner having a specified relation between the electrostatic charge build up time constant of a toner base body and the electrostatic charge build up time constant of the toner. SOLUTION: As the binder resin constituting the toner base body of the base body of a toner 11, a resin having a polar component as hydroxyl group or epoxy group in the molecule of a resin such as polyester resin or epoxy resin is used. Otherwise, a charge controlling agent is added to the binder resin to improve the electrostatic charge degree of the toner base body to a prescribed speed. As the charge controlling agent, a salicylic acid compound, chromium complex or the like is used. An external additive is then added to the toner base body. As the external additive, an inorganic particle such as silicon oxide, titanium oxide or the like is used. The kind and addition quantity of the binder resin and the like are controlled so that the ratio of the electrostatic charge build up time constant of the toner base body τm to the electrostatic charge build up time constant τt of the toner 11 is τm/τt<5. |
