| 摘要 |
<p>A dry toner powder the toner particles of which are triboelectrically negatively charged and are suited for development of an electrostatic charge pattern, wherein said toner particles contain: (1) one or more triboelectrically negatively chargeable thermoplastic resins serving as binder having a volume resistivity of at least 1013 Φ-cm, and (2) at least one substance having a volume resistivity lower than the volume resistivity of said binder, and wherein said substance(s) (2) is (are) capable of lowering the volume resistivity of said binder by a factor of at least 3.3 when present in said binder in a concentration of 5 % by weight relative to the weight of said binder, and wherein said toner powder containing particles including a mixture of said ingredients (1) and (2) under triboelectric charging conditions is capable of obtaining an absolute median (q/d) charge/diameter value (x) lower than 10 fC/10 νm but not lower than 1 fC/10 νm, and said toner powder under the same triboelectric charging conditions but free from said substance(s) (2) then has an absolute median q/d value (x) at least 50 % higher than when said substance(s) (2) is (are) present, and wherein the distribution of the charge/diameter values of the individual toner particles is characterized by a coefficient of variation ξ « 0.33.</p> |
