Negatively chargeable toner for developing latent electrostatic images
AssigneeRicoh Company, Ltd.
InventorsKazuhito Watanabe, Toshiki Nanya, Yasuaki Iwamoto
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Abstract
A negatively chargeable toner for developing latent electrostatic images is composed of a coloring agent; releasing agent; a binder resin including a polyester and a styrene - acryl-based polymer component with a weight-average molecular weight of 50,000 to 150,000, a number-average molecular weight of 2,000 to 12,000, and a glass transition temperature of 55.degree. to 70.degree. C. at a mixing ratio by weight in the range of (95:5) to (50:50); and a charge controlling agent including at least one phthalic ester which is mixed with the styrene - acryl-based polymer component, and at least one fluorine-containing quaternary ammonium salt.
Claims11
A negatively chargeable toner for developing latent electrostatic images comprising:
- a coloring agent;
- a releasing agent;
- a binder resin comprising a polyester and a styrene-acryl-based polymer component at a mixing ratio by weight in the range of (95:5) to (50:50), said styrene-acryl-based polymer component having a weight-average molecular weight of 50,000 to 150,000, a number-average molecular weight of 2,000 to 12,000, and a glass transition temperature of 55.degree. to 70.degree. C.;
- and
- a charge controlling agent comprising at least one pthalic ester of general formula (I) which is mixed with said styrene-acryl-based polymer component:
- ##STR4## wherein R.sup.1 and R.sup.2 each represent a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, a phenyl group, or a phenyl-group-containing saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and at least one fluorine-containing quaternary ammonium salt of general formula (II):
- ##STR5## wherein X represents --SO.sub.2 -- or --CO--;
- R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each represent hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aryl group;
- Y represents iodine or bromine;
- and m and n are integers of 1 to 20.
Dependencies are inferred from the claim text.