| 摘要 |
PURPOSE:To obtain high-quality copied images over a long period of time by using a sufficiently electrostatically charged positive chargeable toner and negative chargeable toner as the developer. CONSTITUTION:The developer consisting of the positive chargeable toner 12 which consists essentially of a binder resin and magnetic material, is incorpo rated with a quaternary ammonium salt and aliphat. metal salt having 2.0 to 4.5wt.% metal content and 110 to 145 deg.C m. p. as a charge control agent and has the respective electrostatic charge controllability of Tc>=Tb>=Ta in frictional electrification quantity to iron powder, binder resin and the negative chargeable toner 13 which is incorporated with a metal-contg. complex as a charge control agent at 0.1 to 5wt.% of the weight of the binder resin is used. Ta denotes the electrostatic charge quantity (muC/g) of the toner contg. the quater nary ammonium salt alone; Tb denotes the electrostatic charge quantity (muC/g) of the toner contg. the aliphat. metal salt alone; Tc denotes the electrostatic charge quantity of the toner into which both of the quaternary ammonium salt and the aliphat. metal salt are incorporated. The magnetic toner which yields stable images of a high grade at all times without being affected by the environment of temp., humidity, etc., is obtd. in this way. |
