Dry type developer for electrophotography
AssigneeRicoh Company, Ltd.
InventorsMitsuo Aoki, Nobuhiro Nakayama, Yasuo Asahina, Hiroyuki Fushimi, Kayo Makita, Yasuaki Iwamoto
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AssigneeRicoh Company, Ltd.
InventorsMitsuo Aoki, Nobuhiro Nakayama, Yasuo Asahina, Hiroyuki Fushimi, Kayo Makita, Yasuaki Iwamoto
Estimating the term…
The present invention relates to the positively chargeable black toner particles which comprise binder resins, carbonblack as a main colorant, quaternary anmonium salt of the following formula (I) as a charge control agent and .beta.-form Cu-phthalocyanine as a stabilizing agent for chargeability of toner particles without being affected by the change of environmental conditions. ##STR1## Wherein R.sub.1 is C.sub.1 -C.sub.8 alkyl or benzyl, R.sub.2 and R.sub.3 are each C.sub.1 -C.sub.18 alkyl, R is C.sub.1 -C.sub.118 alkyl or benzyl, X is hydroxy or amino, and Y is hydoroxy or hydrogen; (c) .beta.-form Cu-phthalocyanine; and (d) carbonblack. The present invention further relates to the two component dry-type developer composed by the improved above said positively chargeable toner particles and the carrier particles coated with silicone polylmers which have the strong durability without being changed to a supent carrier particles for a use of long time period.
A toner particle of a two component dry-type developer capable of being charged positively comprises (a) a binder resin;
A developer composition composed by toner particles and carrier particles, said toner particles comprising (a) a binder resin;
Dependencies are inferred from the claim text.