Ricoh Company, Ltd.

Yasuyuki Hosogi

Shin Hasegawa

Keishi Taniguchi

Minoru Hakiri

Yuji Natori

Shigeo Hatada

Shigeaki Kimura

Aimi Suzuki

Toshiaki Azuma

The object of the present invention is to provide a water-based pigment dispersion containing a pigment, a dispersing agent, a resin emulsion, and water, the water-based pigment dispersion is subjected to a heat treatment. The present invention also provides a water-based pigment ink containing the water-based pigment dispersion, a dispersing agent, a resin emulsion, and water.

Water-based pigment dispersion, production method thereof, water-based pigment ink, production method thereof, ink record, inkjet recording apparatus, and inkjet recording method

The present invention provides a pigment dispersion that contains a carbon black, a dispersing agent and water, wherein the carbon black is any one of a channel black and a gas black, the dispersing agent is a sodium naphthalenesulfonate formalin condensate, and the total content of a dimer, a trimer and a tetramer of naphthalenesulfonate in the sodium naphthalenesulfonate formalin condensate is 20% by weight to 80% by weight. The present invention also provides an inkjet ink using the pigment dispersion.

Pigment dispersion, inkjet-ink using the pigment dispersion, image forming process, and image forming apparatus

An inkjet ink including water; a particulate pigment; a dispersant; and an emulsion, wherein the particulate pigment has an average particle diameter (D) not greater than 100 nm, and the standard deviation of particle diameter distribution of the particulate pigment is less than one half of the average particle diameter (D). An inkjet cartridge containing the inkjet ink. An inkjet recording apparatus including the inkjet cartridge and a carriage configured to carry the ink cartridge. An inkjet recording method including discharging the inkjet ink from a nozzle of a recording head to form an ink image on a recording paper. An image formed on a recording material in accordance with the inkjet recording method.

Inkjet, inkjet cartridge containing the inkjet ink, inkjet recording apparatus using the inkjet ink, inkjet recording method using the inkjet ink, and image formed by the inkjet recording method

A thermosensitive recording paper comprising a support sheet and a thermosensitive coloring layer formed thereon, which support sheet comprises needle-leaf tree pulp in an amount ratio of 10 to 50 wt. % of the absolute dry weight of the support sheet, with the maximum length of the fibers in the needle-leaf tree pulp being 4 mm or less.

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Numazu, Japan

Yasuyuki Hosogi