Developer for electrostatic image

Abstract

Abstract PURPOSE: To improve the density, sharpness and distinctness of transfer images by dispersing magnetic material fine powder in the fixing medium containing the specific copolymer and selecting the electrostatic capacity, dielectric constant and electric resistance of developer particles in a fixed range. CONSTITUTION: Magnetic material fine powder of 45W65wt% based on the total weight is dispersed in the fixing medium containing the copolymer of 75000W150000 in weight-average molecular weight composed of one or more kinds of vinyl aromatic monomers and one or more kinds of mono- and diethylene base unsaturated monomers and the electrostatic capacity of the developer particles measured under the conditions of inter-electrode distance 0.65mm, electrode sectional area 1.43cm 2 and inter-electrode load 105g/cm 2 is so selected as to become 7.8W11.7PF, the dielectric constant 4W5 and the electric resistance 5W10 13 Ω.cm or more. The use of this one-component magnetic developer improves the density of transfer images and yields the transfer images of superior reproduction of intermediate colors as well. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Nobuhiro Miyagawa
• 👤 Takashi Tejima

Bibliographic Details