ELECTROSTATIC LATENT IMAGE DEVELOPER

摘要

PURPOSE:To improve the rising speed of the electrostatic charge of a toner and to prevent the splashing of the toner of the electrostatic latent image developer formed by using the toner contg. styrene copolymers on a low mol.wt. side and high mol.wt. side as a binder resin. CONSTITUTION:The styrene copolymer A having the number average mol.wt. within a 1X10<3> to 2X10<4> range and having 70 to 98wt.% copolymn. ratio WA of the styrene monomer at >=10 pts.wt. and <50 pts.wt. and the styrene copolymer B having the number average mol.wt. within a 1X10<5> to 2X10<6> range and 50 to 90wt.% copolymn. ratio WB of the styrene monomer at >=50 pts.wt. and < 90 pts.wt. are incorporated into the binder resin. Magnetic powder is incorporated at 0.5 to 13wt.% into the toner satisfying the relation WA>=WB in the copolymn. ratio WA, WB of these styrene monomers. A magnetic carrier essentially consisting of such toner and a magnetic material is used.