| 摘要 |
PURPOSE:To prevent the exposure of magnetic particles to a toner surface and the liberation thereof and to improve the quality and stability of a copied image by preliminarily coating a magnetic material with an acrylic resin by a polymn. method. CONSTITUTION:The acrylic resin-coated magnetic particles obtd. by adsorbing the monomer of the acrylic resin to the magnetic material which is made hydrophobic by an oil soluble activator, adding a polymn. initiator thereto and polymerizing the monomer is used. An alpha-methylene aliphat. monocarboxylic acid and the ester thereof or acryl type deriv. is used for the monomer of the acrylic resin. For example, 'Aerosel OT(R)' is used for the oil soluble activator. A radical polymn. initiator is used for the polymn. initiator and includes, for example, azo bis-isobutyro nitrile. The copied image quality and the stability thereof are improved by using such magnetic particles. |
