The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 15, 1994
Filed:
Dec. 21, 1992
Hideki Ohta, Ikoma, JP;
Tatsuo Imafuku, Higashiosaka, JP;
Masami Tsujihiro, Katano, JP;
Toshiro Tokuno, Takarazuka, JP;
Hiroshi Shimoyama, Osaka, JP;
Nobuhiro Hirano, Osaka, JP;
Mita Industrial Co., Ltd., Osaka, JP;
Abstract
Spheroidal toner for developing electrostatic images is composed of a binding resin as its main component in which at least carbon black and a dispersion stabilizer for the carbon black are contained, the conductivity of the toner being in the range of 5.times.10.sup.-11 to 5.times.10.sup.-9 S/cm. The conductivity of the toner is preferably within the range of 4.times.10.sup.-10 to 5.times.10.sup.-9 S/cm. It is also desirable that the dispersion stabilizer be composed of at least one selected from the group consisting of oil-soluble dyes, coupling agents, and surfactants, and that according to Wadel's practical spheroidicity, the toner be within the range of 0.95 to 1.0. A method of manufacturing the toner includes the steps of: forming grafted carbon black by prepolymerization of a polymerizable composition containing carbon black and a monomer forming a binding resin; adding a carbon black dispersion stabilizer to the prepolymerized composition; and suspending the composition in an aqueous medium and polymerizing the suspended particles in the presence of a polymerization initiator.