US 5,296,326 AGranted

Magnetic toner

AssigneeCanon Kabushiki Kaisha

InventorsMasaaki Taya, Hirohide Tanikawa, Yasutaka Akashi, Makoto Unno, Masaki Uchiyama, Kiichiro Sakashita

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Abstract

A magnetic toner for electrophotography having stable triboelectric chargeability under various environmental conditions may be provided by using magnetic iron oxide particles having a moderately high surface Feo content, specified by the following conditions: (a) a dissolved Fe (II) content in dissolved total iron of 14-33.3 wt. % at a dissolved total iron percentage of 5.+-.1 wt. %, (b) a dissolved Fe (II) content in dissolved total iron of 17-33.3 wt. % at a dissolved total iron percentage of 10.+-.1 wt. %, and (c) a dissolved Fe (II) content in dissolved total iron of 18-33.3 wt. % at a dissolved total iron percentage of 15.+-.1 wt.

Claims52

Dependent claims

A magnetic toner comprising magnetic toner particles containing at least a binder resin and magnetic iron oxide particles, wherein the distribution of Fe (II) in a surface layer of said magnetic iron oxide particles satisfy the following conditions (a)-(c):

(a) a dissolved Fe (II) content in dissolved total iron of 14-33.3 wt. % at a dissolved total iron percentage in the range of 4-6 wt. %;
(b) a dissolved Fe (II) content in dissolved total iron of 17-33.3 wt. % at a dissolved total iron percentage in the range of 9-11 wt. %;
and
(c) a dissolved Fe (II) content in dissolved total iron of 18-33 wt. % at a dissolved total iron percentage in the range of 14-16 wt. % and said magnetic iron oxide particles have an FeO content based on total Fe of 30-40 wt. %.

1 more element

Dependencies are inferred from the claim text.