The principle of thermal paper is placed above 70 ℃ environment, if the thermal paper prints, heat-sensitive coating began to change color. But also to talk about the reasons for its color from its ingredients. The heat-sensitive thermal paper coating composition mainly two: one is called colorless dye or leuco dye; the other is a color agent. Such thermal paper is also known as a two-component type thermal recording paper chemical. Used as colorless dye are mainly: crystal violet lactone tritylaminothiazole benzene phthalocyanine system (CVL), fluoran system, colorless benzoyl methylene blue (BLMB) or Spiropyran system and other substances. The main principle used dispersants are: polyvinyl alcohol L-3266, polyvinyl alcohol GL-05, polyvinyl alcohol KL-03 (Nippon Synthetic Chemical production). Common topcoat and undercoat aid mainly: gohsefimer Z-200, polyvinyl alcohol T-350, polyvinyl N-300. Used as coloring agents mainly: p-hydroxy benzoic acid and its esters (PHBB, PHB), salicylic acid, 2 thermal paper, 4-hydroxy acid or an aromatic sulfone and other substances. Heat, colorless dye and the color developing agent in case of occurrence of thermal paper, chemical reaction produces a color, then use thermal paper to print the received signal or direct thermal paper printing thermal printer brands on the fax machine, fax on the show. Since the colorless dye used in many kinds of varieties, so there are different colors appearing handwriting, blue, purple, black. Thermal paper manufacturers, Kaifeng Paper (certified), thermal paper supplied by Xinxiang City Paper Co., Ltd. Kaifeng. Kaifeng, Xinxiang City Paper Co., Ltd. (www.xxkfzy.cn) Henan Xinxiang, a leader in paper and paper processing, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs . Paper in Kaifeng leadership with the staff warmly welcome all inquiries negotiations to create a better future Kaifeng Paper.