PURPOSE: To form stably a sharp image having high density without fogging for a long period of time by consisting a carrier of particle groups of prescribed grain sizes made by dispersing the pulverous powder of a magnetic material into a binder resin, consisting the pulverous powder of the magnetic material of the particle groups of iron and/ or iron alloy having specific saturation magnetization intensity and grain size and using a two-component developer contg. such small-size carrier which is hardly scatterable.
CONSTITUTION: The carrier of the developer is formed by dispersing and incorporating the pulverous powder of the magnetic material into the binder resin and incorporating further additive components such as charge control agen thereto according to need. The average grain size thereof is made 10W50μm. The pulverous powder of the magnetic material is the magnetic material consisting of the iron and/or iron alloy having ≥150emu/g saturation magnetization intensity and the average grain size of the magnetic material particles is 0.01W10μm. The iron is used as the essential component for the iron alloy to be used for the magnetic material and 1 or ≥2 kinds among carbon, phosphorus, boron, silicon, tungsten, etc. are used for the other component elements. These magnetic materials are usable alone or in combination with ≥2 kinds. The ratio at which the pulverous particle of the magnetic material is incorporated into the carrier is 40W90wt% by the weight of the carrier.
KOIZUMI FUMIO
KASUYA RYUHEI
SHIGETA KUNIO
Next Patent: JPS6132858