Ricoh Company, Ltd.

Hiroshi Sakamoto

Norihiko Inaba

Keishi Taniguchi

Takanori Motosugi

Hiroshi Yaguchi

Kazumi Ohtaki

Susumu Iwata

Kanjirou Kawasaki

Hiroaki Inoue

Minoru Hagiri

Minoru Nomura

Yoshihiro Koseki

Shinichi Asami

A thermosensitive recording material is disclosed, which comprises (a) a heat insulating support having a foamed portion with minute voids therein, (b) an undercoat layer formed on the heat insulating support, comprising as the main component a film-forming polymeric material in an amount ranging from more than 50 wt. % to 100 wt. % of the entire weight of the undercoat layer, and (c) a thermosensitive coloring layer formed on the undercoat layer, comprising a leuco dye and a color developer for inducing color formation in the leuco dye upon application of heat thereto.

Thermosensitive recording material

A thermosensitive recording material is disclosed which comprises (a) a support material, (b) a plurality of undercoat layers successively overlaid on the support material, and (c) a thermosensitive recording layer formed on the undercoat layers.

A multi- and full-color thermosensitive recording method of recording multi- or full-color images on a multi-color thermosensitive recording sheet capable of forming 2 to 4 different colors by use of a thermal head is disclosed, with the improvement that the picture elements of a thermal head are grouped so as to be operative in the form of a matrix consisting of n picture elements in the main scanning direction and m picture elements in the sub-scanning direction, each matrix is assigned to 2 to 4 alternatively independent colorings and thermal recording is performed in such a manner that, of the n.times.m picture elements in each matrix, the number of the picture elements for each color formation is changed, whereby multi- and full-color recording with a multi-step pseudo density gradation is attained.

Multi-layer full-color thermosensitive sheet recording method

A thermosensitive recording sheet comprises a support material; a thermosensitive coloring layer formed on the support material, comprising a colorless or light-colored leuco dye, and an acidic material which colors the leuco dye upon application of heat thereto; and a protective layer formed on the thermosensitive coloring layer, comprising a water-soluble polymeric binder and silica powder with an oil absorption of 150% or more and with a bulk density of 5 ml/g or more, which are measured in accordance with Japanese Industrial Standard K 5101. This thermosensitive recording sheet has high dynamic thermal coloring sensitivity, is capable of yielding sharp images with high image density at low energy consumption with good thermal head-matching properties, and is resistant to chemicals.

Thermosensitive recording sheet

A two-color thermosensitive recording material using leuco dyes is disclosed, which is capable of forming two different colors when heated at different temperatures, black or blackish color at a low temperature and another color at a high temperature, comprising a support material, a high-temperature color-forming material overlaying the support material, a decolorization layer overlaying the high-temperature color-forming layer, and a low-temperature color-forming layer overlaying the decolorization layer, and when necessary, an intermediate layer interposed between the decolorization layer and the low-temperature color-forming layer, the decolorization layer containing an aliphatic amine or a morpholine derivative of the formula of ##STR1## which are fully defined in the specification, and the low-temperature color-forming layer containing as a color developer a thiourea derivatives of the formula, ##STR2## which is fully defined in the specification.

Two-color thermosensitive recording material

A thermosensitive recording sheet comprising a support material; a primer layer formed on support material, comprising a filler and a binder agent; a thermosensitive coloring layer formed on the primer layer, comprising a colorless or light-colored leuco dye, and an acidic material which colors the leuco dye upon application of heat thereto; and a protective layer formed on the thermosensitive coloring layer, comprising a water-soluble polymeric binder agent and a filler. This thermosensitive recording sheet has high dynamic thermal coloring sensitivity and is capable of yielding sharp images with high image density at low energy consumption with good thermal-head-matching properties such that materials are not generated which come out of the thermosensitive recording layer and adhere to the thermal pen or head during the recording process, thereby causing the thermal pen or head to stick to the thermosensitive recording sheet.

A thermosensitive recording material comprising a support material and a thermosensitive coloring layer formed on the support material, the thermosensitive coloring layer comprising a colorless or light-colored coloring material and a color developing material capable of coloring the coloring material upon application of heat thereto, is disclosed, in which the color developing material comprises at least one first bisphenol derivative of the formula (I) and at least one second bisphenol derivative of the formula (II), ##STR1## wherein n is an integer of 1 or 2, ##STR2## wherein X represents halogen, Y represents ##STR3## m is an integer of 1 or 2, and the substitution positions of Xm in the benzene rings are symmetrical with respect to Y.

A thermosensitive recording material comprising a support member and thermosensitive layer formed on the support member, the thermosensitive layer comprising a fluoran compound represented by the formula (I), an acidic material capable of coloring the fluoran compound upon application of heat thereto, and a benzamide compound of the formula (II) ##STR1## wherein R.sup.1 represents an alkyl group with 5 to 8 carbon atoms, R.sup.2 represents an alkyl group with 1 to 8 carbon atoms, and R.sup.3 represents an alkyl group with 1 to 2 carbon atoms; ##STR2## wherein R.sup.4 represents an alkyl group with 10 to 30 carbon atoms, and A represents hydrogen or --COOR.sup.5 in which R.sup.5 represents an alkyl group with 1 to 10 carbon atoms.

An improved thermosensitive recording material comprising a support material is disclosed and a thermosensitive coloring layer formed on the support material, the thermosensitive coloring layer comprising (a) a colorless or light-colored coloring material and (b) a developing material capable of coloring the coloring material upon application of heat thereto, said developing material comprising a p-hydroxybenzoic acid ester of the formula (I) and a bisphenol derivative of the formula (II), with a melting point ranging from 80.degree. C. to 130.degree. C., the formulas (I) and (II) being: ##STR1## wherein R represents alkyl having 1 to 4 carbon atoms, or benzyl, ##STR2## wherein R.sup.1 represents hydrogen or methyl; R.sup.2 represents hydrogen or alkyl having 1 to 5 carbon atoms; R.sup.3 represents hydrogen or methyl; and R.sup.4 represents hydrogen or alkyl having 1 to 4 carbon atoms.

The present invention provides a heat-sensitive recording sheet which is composed of a support and a heat-sensitive layer formed on said support, said heat-sensitive layer consisting essentially of a color-developable substance and an organic acid substance capable of making said color-developable substance develop a color when heated and containing at least one member selected from the group consisting of condensate of higher fatty acid amide and formaldehyde and condensate of higher fatty acid and ethylene diamine and at least one member selected from the group consisting of vegetable waxes and mineral waxes.

Growing community of inventors

Numazu, Japan

Hiroshi Sakamoto