Canon Kabushiki Kaisha

Aki Takano

Hideki Takayama

Yoshihisa Yamashita

Kenji Nishiguchi

Shin-ichi Sato

Katsuhiko Suzuki

Junichi Sakai

Kousuke Yamasaki

Itaru Tsuji

Shin-Ichi Sato

An ink set includes a combination of a first ink and a second ink, the first ink containing a self-dispersion pigment having at least one hydrophilic group directly or through another atomic group bonded to the surface of the pigment particle, and ammonium ions, the second ink containing a pigment, a polymer having an acid value of 160 mg KOH/g or less, and alkali metal ions, wherein the first ink further contains a compound (A) selected from nonionic surfactants and/or a compound (B) selected from the group consisting of polyethylene glycol with an average molecular weight of 600 to 2,000, &#x3b1;,&#x3c9;-alkanediol having six carbon atoms, and an imidazolidinone derivative.

Ink set, ink jet recording method, ink cartridge, recording unit, and ink jet recording apparatus

An ink jet recording apparatus is provided with a plurality of inks and includes a unit configured to perform a recovery operation by suction of inks from a plurality of ink ejection portions using a suction cap, wherein the plurality of inks include an ink set including a combination of at least a first ink and a second ink, the first ink containing (i) a self-dispersion pigment having at least one hydrophilic group directly or through another atomic group bonded to the surface of the pigment, and (ii) ammonium ions, the second ink containing a pigment, a polymer having an acid value of 160 mg KOH/g or less, and alkali metal ions, and the suction cap used in the recovery operation is individually provided for each of the first ink and the second ink.

Ink jet recording apparatus and ink jet recording method

Provided is an aqueous ink with high storage stability and scratch resistance at such a high level that the coloring material of an image is not scraped off even when lightly touched with a sharp product. The aqueous ink includes a water-insoluble coloring material and plural polymers. The plural polymers include a polymer A which relatively contributes to dispersion of the water-insoluble coloring material and a polymer B which does not relatively contribute to the dispersion of the water-insoluble coloring material compared to the polymer A. The polymer A includes a block copolymer having an acid value of 120 mgKOH/g to 180 mgKOH/g and having an ethylene oxide group as a nonionic group. The polymer B has an acid value of 150 mgKOH/g or less and a hydrogen bond parameter (&#x3b4;h) of the polymer obtained by solubility parameters of monomers constituting the polymer of 1.0 cal/cmor more and 3.2 cal/cmor less.

Aqueous ink, ink jet recording method, ink cartridge, recording unit, ink jet recording apparatus, and image

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Kawasaki, Japan

Aki Takano