| 摘要 |
PURPOSE:To improve an offset preventing effect and to obtain stable images even after long-period copying by specifying the release agent in a toner, the fine particles content of the toner and the core material of a carrier. CONSTITUTION:This developer consists of at least the toner essentially consisting of a binder resin, coloring agent and the release agent and the resin- coated carrier. The release agent in the toner is low mol.wt. polyalkylene and the content of the release agent is 3-10wt.% by the weight of the binder resin. The fine particles content of the toner (number % of <=5mum grain size) is <=15%. The core material of the carrier has <=150mum average grain size, <=5.5 specific gravity, and 40-65emu/g (in the case of 1,000Oe impressed magnetic field) saturation magnetization. The electrostatic charge quantity of the toner is thereby stabilized even after long-period repeated copying and the welding of the toner to the carrier surface is hardly generated. The excellent offset resistance is thus obtd. |
