Ricoh Company, Ltd.

Miyoshi Yushi Kabushiki Kaisha

Richo Company, Ltd.

Katsuhisa Kamio

Kyoji Tsutsui

Masafumi Torii

Hiromi Furuya

Masafumi Moriya

Kazuo Hosoda

Katsushi Sugiyama

Fumio Kawamura

Hiroaki Matsui

Katsuaki Kokubo

Masaru Shimada

Tadafumi Tatewaki

Shoji Maruyama

Masatake Kawashima

A reversible thermosensitive composition including a coloring agent and a developer and capable of assuming a colored state and a discolored state depending upon the thermal hysteresis thereof. The developer is a phenol compound represented by the formula: ##STR1## wherein n is an integer of between 1 and 3, X represents a divalent group having a nitrogen atom or an oxygen atom, R.sup.1 represents a substituted or non-substituted aliphatic hydrocarbon group having at least two carbon atoms and R.sup.2 represents a hydrocarbon group. A reversible thermosensitive recording medium has a thermosensitive recording layer containing the above composition.

Reversible thermosensitive coloring composition and reversible

A reversible thermosensitive composition including a coloring agent and a developer and capable of assuming a colored state and a discolored state depending upon the thermal hysteresis thereof. The developer is a phenol compound represented by the formula: ##STR1## wherein R.sup.1 and R.sup.3 represent, independently from each other, a substituted or non-substituted hydrocarbon group, R.sup.2 represents a substituted or non-substituted aliphatic hydrocarbon group having at least two carbon atoms, with the proviso that the total number of carbon atoms of R.sup.1, R.sup.2 and R.sup.3 is at least 8, X and Y represent, independently from each other, a divalent group having a nitrogen atom or an oxygen atom and r is an integer of between 1 and 3.

A reversible thermosensitive composition including a coloring agent and a developer and capable of assuming a colored state and a discolored state depending upon the thermal hysteresis thereof. The developer is a phenol compound represented by the formula: ##STR1## wherein R.sup.1 represents a substituted or non-substituted divalent hydrocarbon group having at least two carbon atoms, R.sup.2 represents a substituted or non-substituted hydrocarbon group, X and Y represent, independently from each other, a divalent group having a hetero atom and r is an integer of between 1 and 3. A reversible thermosensitive recording medium includes a support and a thermosensitive layer including the above composition.

Reversible thermosensitive composition and reversible thermosensitive

A reversible thermosensitive medium having a support and a thermosensitive layer, the layer comprising a composition including a coloring agent and a developer and capable of assuming a colored state and a discolored state depending upon the thermal hysteresis thereof. The developer is a phenol compound represented by the formula: ##STR1## wherein n is an integer of between 1 and 3, X represents a divalent group having a nitrogen atom or an oxygen atom, R.sup.1 represents a substituted or non-substituted aliphatic hydrocarbon group having at least two carbon atoms and R.sup.2 represents a hydrocarbon group. A reversible thermosensitive recording medium has a thermosensitive recording layer containing the above composition.

Reversible thermosensitive recording medium

A thermally reversible color forming composition which includes an electron-donating chromophoric compound and an electron-accepting compound, by which formation and deletion of a color image may be carried out by adjusting thermal energy applied to the composition, wherein the electron-accepting compound is a carboxylic acid compound having the following general formula (1):

Thermally reversible color forming composition and thermally reversible

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Kakamigahara, Japan

Katsuhisa Kamio