| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a developer capable of providing a desired image density, excellent in offset resistance, and stabilized in frictional charging characteristic by mixing a high melting point wax, a binder resin and a coloring agent at high speed in a first mixing process, and adding and mixing a low melting point wax at low speed or with a weak force in a second mixing process. SOLUTION: Two-stage mixing process is provided before fusing kneading, in a first mixing process, a high melting point wax, a binder resin, and a coloring agent are mixed at high speed, and in a second mixing process, a low melting point wax is added and mixed at low speed or with a weak force. The mixing at high speed in the first mixing process is performed by use of, for example, a Henschel mixer. The Henschel mixer has a mixing tank 2, and a set of stirring blades 4 consisting of an upper blade and a lower blade are mounted on a vertical shaft protruded from the lower center of the mixing tank 2. In this case, the circumferential speed of the stirring blade 4 is preferably set to 30-50m/sec. Thus, the first developer material is mixed with a relatively strong force.</p> |
