| 摘要 |
<p>PROBLEM TO BE SOLVED: To produce a toner which reduces image defects such as a mark of an aggregate and a vertical streak on printed matter formed with a printer or the like and can form an image having high image density, free from fog and excellent in image characteristics and to further produce a toner which can stably give a high quality image even in an environment at high temp. and high humidity, stably ensures superior image characteristics and electrostatic charge characteristics and is excellent also in durability. SOLUTION: At least inorg. fine particles of <=50nm average particle diameter are added to toner particles contg. a bonding resin and a colorant, they are mixed and the resultant toner is screened with a vibrating screen unit with an ultrasonic oscillator. The operation conditions of the vibrating screen unit in the screening step are controlled so as to satisfy the relations of A-B<=50 deg.C and A<=60 deg.C (A is the mesh temp. of the vibrating screen unit and B is the temp. of the toner after screening).</p> |
