| 摘要 |
PURPOSE:To provide the titled developer with improved developing efficiency, transferring efficiency and halftone reproducibility by dispersing magnetic powder having specified characteristics, higher fatty acid or its metal salt and an alcohol- soluble metal-contg. dye in a vinyl aromatic or acrylic resin. CONSTITUTION:The following components are kneaded with a roll mill: 55pts.wt. magnetic powder such as magnetite powder having >=0.42g/ml bulk density, >=0.35mum average maximum size measured with an electron microscope and 1- 1.55 maximum size/minimum size ratio, a 41.5pts.wt. styrene-acrylic copolymer, 3.5pts.wt. low mol. wt. polypropyrene, 0.5 part zinc stearate and a 0.7 part negative charge controller such as ''BONTRONS-31 ''. The kneaded material is melted, allowed to cool, coarsely pulverized, and finely pulverized with a jet mill to obtain a magnetic toner. |
