Method for manufacturing magnetic toner

Abstract

Abstract PURPOSE:To obtain a spherical magnetic toner having a monodisperse grain size by a process comprising a stage for manufacturing particles by emulsion polymn., a stage for dipping the particles in a solvent which swells the particles but does not dissolve the same, a stage for adding a monomer to the particles, impregnating the same in the particles and polymerizing the monomer, a stage for immersing the particles in a swellable solvent contg. a magnetic material and obtaining a magnetic material polymer, and a drying stage. CONSTITUTION:Monodisperse particles having 1.2mum grain size are first obtd. by an emulsion polymn. using a polymerizable monomer such as styrene or the like. A hexadecanoic dispersion contg. 50wt% magnetic particles and 6wt% AIBN is dropped to the emulsion contg. such particles to swell the above-described polymer particles, whereby 2mum particles are obtd. 20ml such suspension is taken in a separate vessel, and after 1l of aq. soln. contg. an emulsifier is added thereto, 1l of styrene monomer is added to swell the above-described particles and to polymerized the same in the partiles, whereby 8mum particles are obtd. Such particles are dried, whereby 10mum spherical monodisperse toner is obd. When the toner obtd. in the above-mentioned way is used for copying, a sharp image having no photographic fogs is obtd. and the deterioration in the image is not observed even after an endurance test for 100,000 sheets.

Inventors

• 👤 Naoyuki Ushiyama
• 👤 牛山　尚之
• 👤 Ichiro Osaki
• 👤 大崎　一郎
• 👤 Toshiaki Nakahara
• 👤 中原　俊章

Bibliographic Details