GRADATION CONTROL APPARATUS FOR SELF COLORING TYPE COLOR RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a novel gradation control apparatus capable of applying a gradation representation to each coloring dot formed on a multicolor recording medium by heating elements. SOLUTION: A pressure sensitive and thermally sensitive coloring layer of the multicolor recording medium includes a thermally sensitive coloring component and multiple pressure sensitive microcapsules each of which has a pressure-temperature coloring characteristic of creating a first color by being broken at a predetermined pressure in a first temperature range. The thermally sensitive coloring component has a temperature coloring characteristic of crating a second color different from the first color in a second temperature range between a first temperature included in the first temperature range and a second temperature exceeding the upper limit of the first temperature range. A gradation control apparatus applies the gradation representation by a dot gradation method to a mixture of colors in a color mixing temperature region of the first color and the second color.