Described are colour developers of formula (I)

Ar.sup.1—NH—CO—NH—C.sub.6H.sub.4—SO.sub.2—O—C.sub.6H.sub.4—NH—CO—NH—Ar.sup.2   (I),

a heat-sensitive recording material comprising a carrier substrate and also a heat-sensitive, colour-forming layer containing at least one colour former and at least one phenol-free colour developer, wherein the at least one colour developer is the compound of formula (I), and a method for producing this heat-sensitive recording material.

A thermal transfer sheet according to an embodiment of the present disclosure includes a substrate and a sublimation transfer discoloration- or decolorization-imparting layer disposed on one surface side of the substrate, in which the sublimation transfer discoloration- or decolorization-imparting layer contains at least a compound responsible for discoloration or decolorization and a binder resin.

A thermal transfer sheet according to an embodiment of the present disclosure includes a substrate and a sublimation transfer discoloration- or decolorization-imparting layer disposed on one surface side of the substrate, in which the sublimation transfer discoloration- or decolorization-imparting layer contains at least a compound responsible for discoloration or decolorization and a binder resin.

An object of the present invention is to provide a thermal recording material which is excellent in all of the following characteristics: plasticizer resistance, image stability against moisture and heat, the resistance to background fogging under moisture and heat, and the retention of color developing ability. Provided is a thermal recording material having, on a paper support, a heat-sensitive recording layer containing a colorless or light-colored dye precursor and a developer which reacts with the dye precursor on heating and converts the dye precursor to its colored form, the paper support containing 0.25 to 1.0% by mass of a neutral rosin sizing agent relative to the pulp solid content in combination with calcium carbonate and aluminum sulfate, the developer having a phenylureido moiety in its molecule.

The present invention relates to an N-(4-((4-(3-phenylureido)phenyl)sulfonyl)phenyl)benzenesulfonamide in the polymorphic form ω.sup.18.9, characterised by an x-ray powder diffractogram having the Bragg angles (2θ/CuK.sub.α) 10.9, 11.7, 14.6, 15.0, 15.8, 16.6, 17.6, 18.9, 19.4, 20.9, 21.2, 22.0, 23.3, 24.4, 24.7, 26.1, 27.4, 29.4, 34.2, or in the polymorphic form α.sup.21.2, characterised by an x-ray powder diffractogram having the Bragg angles (2θ/CuK.sub.α) 8.7, 9.8, 10.8, 13.2, 13.9, 14.9, 15.2, 16.0, 17.4, 17.7, 18.7, 20.4, 21.2, 21.6, 22.3, 23.0, 23.3, 23.9, 24.4, 25.0, 25.8, 26.6, 28.1, 28.9, 29.4, 30.1, 30.6, 31.8, 34.5, 35.3, 35.6, 36.9, a method for production thereof, use thereof as a colour developer in a heat-sensitive recording material, and a heat-sensitive recording material comprising N-(4-((4-(3-phenylureido)phenyl)sulfonyl)phenyl)benzenesulfonamide in the polymorphic form ω.sup.18.9 or in the polymorphic form α.sup.21.2.

A drawing method according to an embodiment of the present disclosure to be performed on a heat-sensitive recording medium including a recording layer, the recording layer containing a leuco dye and a photothermal conversion agent that absorbs infrared wavelength light, includes: performing drawing in a plurality of first regions, the plurality of first regions each extending in one direction and having gaps therebetween; and thereafter detecting recorded states of the plurality of first regions, calculating differences from the input image information, and performing drawing in a plurality of second regions at recording intensities determined on a basis of the differences, the plurality of second regions each extending in the one direction and being provided at the gaps between the plurality of first regions.

A drawing method according to an embodiment of the present disclosure to be performed on a heat-sensitive recording medium including a recording layer, the recording layer containing a leuco dye and a photothermal conversion agent that absorbs infrared wavelength light, includes: performing drawing in a plurality of first regions, the plurality of first regions each extending in one direction and having gaps therebetween; and thereafter detecting recorded states of the plurality of first regions, calculating differences from the input image information, and performing drawing in a plurality of second regions at recording intensities determined on a basis of the differences, the plurality of second regions each extending in the one direction and being provided at the gaps between the plurality of first regions.

A drawing method according to an embodiment of the present disclosure to be performed on a heat-sensitive recording medium including a recording layer, the recording layer containing a leuco dye and a photothermal conversion agent that absorbs infrared wavelength light, includes: performing drawing in a plurality of first regions, the plurality of first regions each extending in one direction and having gaps therebetween; and thereafter detecting recorded states of the plurality of first regions, calculating differences from the input image information, and performing drawing in a plurality of second regions at recording intensities determined on a basis of the differences, the plurality of second regions each extending in the one direction and being provided at the gaps between the plurality of first regions.

This heat-sensitive recording material is configured to contain, as a color-developing compound, at least one compound represented by one of formulas (1)-(3):

##STR00001##

A primary object of the present invention is to provide a thermosensitive recording material that achieves high recording density and excellent preservability of a recorded part, or to provide a thermosensitive recording material that achieves high recording density, and excellent heat resistant and resistance to thermal background fogging property in a high temperature environment, as well as excellent sticking resistance and resistance to dirt adhesion of head. The present invention is a thermosensitive recording material having a thermosensitive recording layer containing at least a leuco dye and a developer on a support; the thermosensitive recording material containing, as the developer, a sulfonamide compound represented by general formula (1); (a) the thermosensitive recording material further having a protective layer on the thermosensitive recording layer; the protective layer containing at least one type of adhesive agent selected from the group consisting of water soluble adhesive agents and water dispersible adhesive agents; and at least one of the thermosensitive recording layer or the protective layer containing a water resistance-imparting agent; or (b) the thermosensitive recording layer further containing saturated fatty acid amide represented by general formula (2).