Abstract: A perpendicular magnetic recording head is provided, which has a head structure that narrows the erase band width in shingled write recording. A perpendicular magnetic recording head has a main pole that generates a recording magnetic field, a trailing shield positioned on the trailing side of the main pole, and a side shield positioned in the cross-track direction of the main pole. In the structure, a gap length (MP?SS distance) between the side shield and the main pole and a gap length (MP?TS distance) between the trailing shield and the main pole satisfy a relationship, (MP?TS distance)×0.5<(MP?SS distance)<(MP?TS distance)×1.5.

Abstract: A thermal recording material having good image storability and good lightfastness. The recording material does not have background fogging, even when exposed to light in a broad wavelength range or exposed to high-temperature surroundings. The recording material has a thermal recording layer provided on a support, and the thermal recording layer contains a compound of general formula (1), a compound of general formula (2), and a compound of general formula (3).

Abstract: The present invention provides a diazonium salt represented by the following general formula (1) wherein R1 represents a branched alkyl group; R2 and R3 separately represent an alkyl group and may bond to each other to form a ring; R4, R5, and R6 separately represent a hydrogen atom, an alkyl group, or an aryl group and R4 and R5 may bond to each other to form a ring; and X− represents an anion and a heat-sensitive recording material comprising a heat-sensitive recording layer including the diazonium salt and a coupler.

Abstract: The present invention provides a diazonium salt represented by the following general formula (1) wherein R1 represents a branched alkyl group; R2 and R3separately represent an alkyl group and may bond to each other to form a ring; R4, R5, and R6 separately represent a hydrogen atom, an alkyl group, or an aryl group and R4 and R5 may bond to each other to form a ring; and X— represents an anion and a heat-sensitive recording material comprising a heat-sensitive recording layer including the diazonium salt and a coupler.

Abstract: A thermal recording material having good image storability and good lightfastness. The recording material does not have background fogging, even when exposed to light in a broad wavelength range or exposed to high-temperature surroundings. The recording material has a thermal recording layer provided on a support, and the thermal recording layer contains a compound of general formula (1), a compound of general formula (2), and a compound of general formula (3).

Abstract: A heat-sensitive recording material having a support and a heat-sensitive recording layer provided thereon. The heat-sensitive recording layer contains a diazonium salt compound and a coupler which reacts with the diazonium salt compound upon heating to form a color. The heat-sensitive recording layer contains a compound of the following formula (I): ##STR1## wherein R represents a member selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, and an aryl group; X represents a member selected from the group consisting of --COOR.sup.1, --OCOR.sup.--1, --CONR.sup.1 R.sup.2, and --NR.sup.2 COR.sup.1 ; R.sup.1 represents an alkyl group or an aryl group, R.sup.2 represents a member selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group; n represents an integer from 1 to 5.

Abstract: A novel pyrazolone dye represented by the following formula (I), which can be effectively used as a filter dye, an irradiation inhibiting dye, an antihalation dye or the like in a photographic light-sensitive material: ##STR1## wherein R.sub.1 and R.sub.2 each represents --COOR or ##STR2## R and R' each represents a hydrogen atom, an alkyl group, or an aryl group or may combine with each other to form a 5- or 6-membered ring; Q.sub.1 and Q.sub.2 each represents an aryl group; X.sub.1 and X.sub.2 each represents a linkage group; Y.sub.1 and Y.sub.2 each represents a sulfo group or a carboxyl group; L.sub.1, L.sub.2 and L.sub.3 each represents a methine group; L.sub.4 and L.sub.5 each represents an alkylene group; m.sub.1 and m.sub.2 each represents 1 or 2; n represents 0, 1 or 2; p.sub.1 and p.sub.2 each represents 0 or 1; q.sub.1 and q.sub.2 each represent 0, 1, 2, 3 or 4; and s.sub.1 and s.sub.2 each represents 1 or 2.