Abstract:
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) at least one triboelectrically negatively chargeable thermoplastic resin serving as binder having a volume resistivity of at least 10 OMEGA -cm, and 2) at least one resistivity lowering substance being an onium compound having a volume resistivity lower than the volume resistivity lower than the volume resistivity of said binder, and said toner particles are free from non-resinous charge-controlling agent(s) providing negative triboelectric chargeability, 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 toner 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 mu m but not lower than 1 fC/10 mu m, 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 substances(s) is (are) present, and wherein the distribution of the charge/diameter values of the individual toner particles is characterized by a coefficient of variation nu
Abstract:
A dry toner powder of which the powder particles are electrostatically or magnetically attractable and suitable for use in the satin-look development of electrostatic charge images or magnetic patterns and wherein the composition of said powder particles includes at least one substantially colourless transparent thermoplastic (fusible) resin P and at least one substantially colourless compound Q, characterized in that said at least one resin P and said at least one compound Q when after been mixed in molten state followed by solidification form a light-scattering composition that under the measurement conditions of the test R has an optical absorption value of more than 0.10 but not more than 1.0, said resin(s) P and compound(s) Q being present in said toner in a weight ratio range P/Q from 5:1 to 1:5, and the weight ratio of P + Q with respect to the total weight of the toner is equal to or larger than 25:100.
Abstract:
A dry toner powder the toner particles of which are triboelectrically positively charged and are suited for development of an electrostatic charge pattern, wherein said toner particles contain: (1) one or more triboelectrically positively chargeable thermoplastic resins serving as binder having a volume resistivity of at least 10 OMEGA -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) when present in said binder in a concentration of 5 % by weight lower(s) thereof the volume resistivity of said binder by a factor of at least 3.3, 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 mu m but not lower than 1 fC/10 mu m, 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 nu
Abstract:
A dry developer composition suitable for use in the development of an electrostatic charge pattern is described. This developer composition comprises toner particles the average particle diameter whereof is comprised between 3 and 10 microns, and spacing particles the average diameter whereof is under 40 microns and at least twice the average particle diameter of the toner particles, and is characterised in that the part of spacing particles in the overall amount of spacing particles and toner particles is comprised between 1 and 8 % by weight.
Abstract:
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 10 OMEGA -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 mu m but not lower than 1 fC/10 mu m, 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 nu