| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an additive for a pigment which is effective for improving the transparency, coloring power or the like of the pigment even under a thermal hysteresis. SOLUTION: The pigment additive is composed of a disazo compound represented by the formula (wherein n=1-4; R1 is OH, COOM, SO3M, CONH2 or NHCOCH3; and R2, R3, and R4 are each independently H, CH3, C2H5, OCH3, OC2H5, NO2, Cl, OH, COOH, SO3H, CONH2 or NHCOCH3, provided that M in COOM and SO3M is a hydrogen atom or a divalent or trivalent metal), and the pigment composition comprises a disazo pigment and the above pigment additive. Further, the toner for developing electrostatic images comprises the above pigment composition.</p> |
