US Patent No. 9,243,155

INK JET INK, INK CARTRIDGE, AND INK JET RECORDING METHOD


Patent No. 9,243,155
Issue Date January 26, 2016 
Title Ink Jet Ink, Ink Cartridge, And Ink Jet Recording Method
Inventorship Daiji Okamura, Tokyo (JP)
Kousuke Yamasaki, Kawasaki (JP)
Kenji Moribe, Fujisawa (JP)
Kouichirou Okumura, Kawasaki (JP)
Kenichi Shiiba, Warabi (JP)
Hiromitsu Kishi, Kawasaki (JP)
Assignee Canon Kabushiki Kaisha, Tokyo (JP)

Claim of US Patent No. 9,243,155

1. An ink jet ink, comprising: a polyurethane polymer and a self-dispersing pigment, the polyurethane polymer having units
derived from a polyisocyanate, a polyol having no acid group, and a diol having an acid group,
wherein the polyol having no acid group contains a polyether polyol having no acid group, and the percentage (% by mole) constituted
by a unit derived from the polyether polyol having no acid group with respect to all the units derived from the polyol having
no acid group is 80% by mole or more,

the polyether polyol has a number-average molecular weight of 450 or more to 4,000 or less,
the ratio of the percentage (% by mole) of urethane bonds in the polyurethane polymer to the percentage (% by mole) of urea
bonds in the polyurethane polymer is 85.0/15.0 or more to 100.0/0 or less, and

the diol having an acid group is at least one selected from dimethylolpropionic acid and dimethylolbutanoic acid, and the
acid value of the polyurethane polymer resulting from the unit(s) derived from the diol having an acid group is 40 mgKOH/g
or more to 140 mgKOH/g or less.