MAGNETIC DEVELOPER AND DEVELOPING METHOD USING SAID DEVELOPER

摘要

PURPOSE:To have a specific volume grain size distribution and to form stably picture images of high density, by constituting magnetic toner particles of nonbreakable agglomerate of fine particles, and incorporating the magnetic material particles of specific number average grain sizes. CONSTITUTION:Magnetic toner particles made of a fixable resin medium and powder of a magnetic material disposed in said medium are incorporated. The magnetic toner particles consist of nonbreakable agglomerate of the fine particles of the magnetic material and contain the magnetic material particles of 1-8mu number average grain sizes measured with an electronic microscope. Said magnetic toner particles have the volume grain size distributions wherein the above-described magnetic material particles of <=3 times the number average grain sizes are substantially zero and median diameters are 10-35mu. Independent polymers such as vinyl arom. monomers and acrylic monomers or their copolymers are used as the medium for fixing.