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. 24, 1998
Filed:
Jul. 30, 1997
Motoo Urawa, Funabashi, JP;
Keita Nozawa, Shizuoka-ken, JP;
Hiroshi Yusa, Machida, JP;
Takashige Kasuya, Shizuoka-ken, JP;
Yuki Karaki, Shizuoka-ken, JP;
Kazuo Maruyama, Mishima, JP;
Masao Takano, Susono, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A magnetic black toner for electrophotography, includes: (a) magnetic black toner particles containing a binder resin, a magnetic material in 30-200 wt. parts per 100 wt. parts of the binder resin, and a first solid wax, and (b) first inorganic fine powder. The first solid wax (ii) provides a DSC heat-absorption main peak in a range of 60.degree.-120.degree. C., and (iii) shows a molecular weight distribution factor Mw/Mn of 1.0-2.0. The binder resin (iv) has a THF (tetrahydrofuran)-insoluble content of at most 5 wt. %, and (v) contains a THF-soluble content showing a GPC molecular weight distribution including a content (M1) of 40-70% in molecular weights of below 5.times.10.sup.4, a content (M2.ltoreq.M1) of 20-45% in molecular weights of 5.times.10.sup.4 -5.times.10.sup.5, and a content (M3<M2) of 2-25% in molecular weights exceeding 5.times.10.sup.5. (vi) The magnetic black toner exhibits a tan .delta. of 0.5-3.0 in a range of 150.degree.-190.degree. C. and a tan .delta. at 150.degree. C. that is equal to or larger than a tan .delta. at 100.degree. C. The magnetic black toner shows a good fixability in an oil-less fixation system to provide a fixed image having a gloss comparable to one obtained by a non-magnetic color toner.