Fujitsu Corporation

Koji Uchiyama

Akira Nakazawa

Hiroo Ueda

Kohei Kiyota

Masao Tanaka

Hiroshi Sasao

A reusable thermal ink sheet used for thermal printing has a thermal ink composition layer formed on a substrate. The thermal ink composition is a mixture of ink material and filler. The ink material includes a coloring agent and a low temperature melting compound which is a solid at room temperature and is melted during thermal printing in response to a printing image to be transferred. The low temperature melting compound contains a urethane compound as a base material and additive materials as viscosity modulators thereof which lower the viscosity of the ink material at printing temperature. The additive materials contain at least one material selected from the group consisting of fatty acid compounds, fatty acid amide compounds and ester compounds. The improved ink sheet assures a high quality printing image is transferred to a plain paper having a rough surface when thermal printing occurs ten times or more. In addition, ghost images are not formed and background noise is eliminated. Further, a plasticizer is added to the ink material described above, thereby improving the thermal printing ability at a low temperature.

Ink sheet usable in thermal recording

An improved ink composition is disclosed which comprises, in addition to a solvent dye, one or more low-melting compounds, containing hydroxyl and/or ethylene oxide, and inorganic or organic fine particles. An ink sheet comprising such ink composition is also disclosed. The ink sheet is effectively reusable in a heat transfer recording process.

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Yokohama, Japan

Koji Uchiyama