A recording medium includes a recording layer configured to be able to change a color-developed state by an external stimulus and a plurality of structures provided on the recording layer. The recording layer has a plurality of color-developing portions, and a pitch Δd′ between the color-developing portions and a width W of each of the color-developing portions satisfy a relationship of Δd′>W.

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 reversible recording medium according to an embodiment of the present disclosure includes a first recording layer to be colored in a first color, a second recording layer to be colored in a second color, the second color being different from the first color, and a first intermediate layer provided between the first recording layer and the second recording layer, the first intermediate layer including a plurality of layers respectively containing materials different from each other.

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 color laser markable article includes a color laser markable layer provided on a support, the laser markable layer including an infrared absorbing compound; a leuco-dye; and an acid generating compound, wherein the acid generating compound has a structure according to Formulae (I) or (II): ##STR00001##
wherein R1 and R3 independently represent an optionally substituted alkyl group, an optionally substituted (hetero)cyclic alkyl group, an optionally substituted (hetero)aryl group, an optionally substituted aralkyl group, an optionally substituted alkoxy group, an optionally substituted (hetero)cyclic alkoxy group, or an optionally substituted (hetero)aryl group; R2, R4 and R5 independently represent an optionally substituted alkyl, an optionally substituted (hetero)cyclic alkyl group or an optionally substituted aralkyl group; and R1 and R2, R4 and R5, R3 and R4, and R3 and R5 may represent the necessary atoms to form a ring.

A heat-sensitive recording material including a web-shaped substrate having a front side and an opposite reverse side, and at least one heat-sensitive recording layer on either or both of the sides of the web-shaped substrate. The heat-sensitive recording layer contains at least one dye precursor at least one salicylic acid derivative as a (color) developer reactive with this at least one dye precursor, and polyvinylpyrrolidone as auxiliary component augmenting the (color) developer the at least one salicylic acid derivative is 3,5-di(α-methylbenzyl)salicylic acid.

The present invention relates to thermal recording materials comprising (in order): a support (base) layer; one or more “undercoat” layers; a thermal layer (thermosensitive coloring layer); and one or more “protective” layers, wherein the thermal recording material contains an aminocarboxylic and/or phosphorus-based chelating agent.

The thermal (thermosensitive) recording materials of the invention show enhanced plasticizer resistance and/or preprint uniformity.

Described are colour developers of formula (I) Ar.sup.1—SO.sub.2—NH—C.sub.6H.sub.4—SO.sub.2—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 comprising at least one colour former and at least one phenol-free colour developer, the at least one colour developer being the compound of formula (I), and a method for producing this heat-sensitive recording material.

A recording material and a recording sheet having better color-developing performance, storage stability, etc. A recording material which contains (A) at least one color former, (B) at least one compound selected from the group including compounds represented by the following formula (I), and (C) at least one compound selected from the group including compounds represented by the following formula (II) (wherein R.sup.1 to R.sup.3 each represent a halogen atom, a nitro group, a C.sub.1 to C.sub.6 alkyl group, a C.sub.1 to C.sub.6 alkoxy group, a C.sub.2 to C.sub.6 alkenyl group or a C.sub.1 to C.sub.6 haloalkyl group, n1 and n3 each independently represent any integer of 0 to 5, n2 represents any integer of 0 to 4, and X represents —SO.sub.2—O— or —O—SO.sub.2—). ##STR00001##

A drawing and erasing apparatus includes a light source section that includes a plurality of laser elements different from each other in emission wavelength, a multiplexer that multiplexes a plurality of types of laser light beams outputted from the plurality of laser elements, a scanner section that performs scanning with multiplexed light outputted from the multiplexer on a reversible recording medium including a plurality of recording layers, the plurality of recording layers being reversible and different from each other in developed color hue, and a controller that controls a main scanning speed and a sub-scanning speed of the scanner section to cause the scanner section to perform overlapping scanning of a predetermined region on the reversible recording medium during erasure of information written on the reversible recording medium.