| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the magnetic developer stabilized in electrification quantity of toner for a long period even in the case of environmental change and prevented from deterioration of image density and rise of fog by restraining charge-up of a toner, especially, in an environment of low temperature and low humidity. SOLUTION: This magnetic developer is a mixture of magnetic resin grains (a) containing a magnetic powder and a fine powder (b) having an average particle diameter of 0.05-5μm, and this powder (b) is obtained by multistage soap-free polymerization and, in the stage before the final stage, alkylacrylate and/or alkylmethacrylate are polymerized or copolymerized and in the final polymerization stage, polymerizable carboxylic acid or acid salt is polymerized to produce the fine powder.</p> |
