Electrophotographic tower for negative charging
AssigneeMita Industrial Co., Ltd.
InventorsNoriaki Tsubota, Masahiko Kubo, Kazuo Fuji, Akihiro Watanabe, Yoshihisa Kuramae
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Abstract
The electrophotographic toner for negative charging according to the present invention is characterized in that a quaternary ammonium salt having an oxyacid anion is used as a charge-controlling assistant in combination with a charge-controlling agent for negative charging. This quaternary ammonium salt used as the assistant is incompatible with a fixing resin but dispersible therein. Therefore, the toner of the present invention provides a sharp distribution of the charge quantity, and formation of a highly charged toner having no contribution to development or a lowly charged toner causing scattering of the toner can be effectively prevented.
Claims14
An electrophotographic toner for negative charging, comprising
- a fixing resin,
- a colorant,
- a charge-controlling agent for negative charging, and
- a charge-controlling assistant, wherein the charge-controlling assistant is a positive charge-controlling substance which is incompatible with the fixing resin and has a dispersibility in the fixing resin, said charge-controlling assistant being a compound represented by the formula ##STR7## wherein at least one of groups R represents a long chain alkyl or long-chain alkenyl group having at least 8 carbon atoms, other groups R represent a lower alkyl group, a benzyl group, a long-chain alkyl group or a long-chain alkenyl group, with the proviso that at least 2 of these groups R represent a lower alkyl group having up to 4 carbon atoms or a benzyl group, and A represents an oxyacid anion.
Dependencies are inferred from the claim text.