PURPOSE: To provide a dry type developer used for an electrostatic latent image freed of triboelectrification and ground staining, by adding a charge controller to conductive magnetic particles.
CONSTITUTION: A charge controller, such as nigrosine, monoazo dye, triazine, or metal salicylate complex, and when needed, a solution of a polymer as a binder, a colorant and/or an improver of fluidity or the like characteristics are added to conductive magnetic particles 5b consisting of a metal, such as Fe, Ni, Co, or Mn, or a metal oxide of them, or an alloy of them in order to prevent triboelectrification with an electrostatic latent image. The mixture is spray dried or crushed after melt kneading. When the magnetic particles 5b are larger than a magnetic toner 5a, white spots occurs on the image, and on the contrary, when the particles 5b are too small, electrostatic image transfer is made unfavorable. A preferable volume average particle diameter of the particles 5b is 1/5W4/5 of the toner 5a, and more preferably, 3/10W2/3.
TOSAKA HACHIROU
MINAMITANI TOSHIKI
