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.

Date of Patent:
Mar. 07, 2017

Filed:

Jul. 30, 2014
Applicant:

Canon Kabushiki Kaisha, Tokyo, JP;

Inventors:

Shohei Tsuda, Suntou-gun, JP;

Koji Nishikawa, Susono, JP;

Katsuhisa Yamazaki, Numazu, JP;

Yojiro Hotta, Mishima, JP;

Kazuo Terauchi, Numazu, JP;

Motohide Shiozawa, Mishima, JP;

Takeshi Naka, Suntou-gun, JP;

Takuya Mizuguchi, Suntou-gun, JP;

Takayuki Itakura, Mishima, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03G 9/08 (2006.01); G03G 9/083 (2006.01); G03G 9/087 (2006.01); G03G 9/097 (2006.01);
U.S. Cl.
CPC ...
G03G 9/0839 (2013.01); G03G 9/081 (2013.01); G03G 9/083 (2013.01); G03G 9/0819 (2013.01); G03G 9/0827 (2013.01); G03G 9/0833 (2013.01); G03G 9/08755 (2013.01); G03G 9/09716 (2013.01); G03G 9/09725 (2013.01);
Abstract

Provided is a magnetic toner in which enhancement of initial transfer efficiency and transfer efficiency that is stable during a long-term use are achieved by simultaneously suppressing the friction force between the toner and a drum and the cohesion between toners, and further the degradation in chargeability and fluidity caused by the deterioration of the toner. The magnetic toner includes: a magnetic toner particle; a first external additive; and a second external additive. The first external additive includes an organic-inorganic composite fine particle, a plurality of convexes derived from an inorganic fine particle being present on a surface of the organic-inorganic composite fine particle, and has a number-average particle diameter of 50 nm or more and 500 nm or less. The second external additive includes a silica fine particle and has a number-average particle diameter of 5 nm or more and 30 nm or less. A shear load calculated from a rotation torque is 0.50 kPa or more and 2.00 kPa or less when a disc-shaped disc is pressed against a surface of a magnetic toner powder layer, the magnetic toner powder layer being produced by applying a vertical load of 9.0 kPa to the magnetic toner, under a vertical load of 5.0 kPa, and the disc which is being pressed is rotated, and an absolute value |ζ(T)−ζ(A1)| of a difference between a zeta potential ζ(T) of the magnetic toner particle dispersed in water and a zeta potential ζ(A1) of the first external additive dispersed in water is 50 mV or less.


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