Patent ID: 8258079

Claim:
A heat-sensitive transfer sheet, comprising: a base film; at least one dye layer containing at least one heat-transferable dye and a resin formed on one side of the base film; and a heat-resistant lubricating layer containing a lubricant and a resin formed on the other side of the base film; wherein the heat-resistant lubricating layer contains a compound represented by formula (P) as the lubricant: {(R 1a O)(R 2a O)P(═O)O} m M Formula (P) wherein M represents a hydrogen atom, a metal ion, or an ammonium ion; R 1a represents a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aryl group; R 2a represents a hydrogen atom, a metal ion, an ammonium ion, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aryl group; m has the same valence as that of M and represents a number of from 1 to 6; and wherein, when a characteristic X-ray intensity originated from K-line of phosphorus element in the heat-resistant lubricating layer, which intensity is obtained by irradiating an electron beam accelerated at 20 kV and having a beam size of 1 μm or less from the heat-resistant lubricating layer side of the heat-sensitive transfer sheet, is measured with respect to each points within a 200 μm square region, using an energy-dispersive X-ray spectroscope, the largest value of the characteristic X-ray intensity is at least 2.5 times or more as large as the smallest value of the characteristic X-ray intensity within the 200 μm square region, and a plurality of maximum regions having a maximum value of the characteristic X-ray intensity originated from K-line of phosphorus element exist in the 200 μm square region, and a variation coefficient that is obtained by dividing a standard deviation of the maximum values of the characteristic X-ray intensity among these maximum regions with an average value of the characteristic X-ray intensities is 0.25 or less.