|
Thermal paper is a special fine paper that is coated with a chemical that changes color when exposed to heat. It is used in thermal printers and particularly in inexpensive or lightweight devices such as adding machines, cash registers, and credit card terminals. The surface of the paper is coated with a solid-state mixture of a dye and a suitable matrix; a combination of a fluoran leuco dye as an example. When the matrix is heated above its melting point, the dye reacts with the acid, shifts to its colored form, and the changed form is then conserved in a metastable state when the matrix solidifies back quickly enough. Usually, the coating will turn black when heated, but coatings that turn blue or red are sometimes used. While an open heat source, such as a flame, can discolor the paper, a fingernail swiped quickly across the paper will also generate enough heat from friction to produce a mark. Multicolor thermal paper first became available in the early 1990s with the introduction of the Fuji Thermo-Autochrome (TA) system.〔U. S. Patent 5,216,438, ''Direct color thermal printing method for optically and thermally recording a full-color image on a thermosensitive recording medium'', by S. Nakao, N. Katsuma and A. Nagata, Fuji Photo Film Co. (1993).〕 This was followed in the early 2000s by the development of the Polaroid "zero-ink" (ZINK) system.〔U. S. Patent 7,166,558, ''Thermal imaging system'', Bhatt et al., (2007).〕 Both of these methods rely on multi-layer coatings with three separate colorizing layers, but different methods are used for independent activation of each layer. ==History== The earliest direct thermal papers were developed by NCR Corporation (using dye chemistry) and 3M (using metallic salts). The NCR technology became the market leader over time, although the image would fade rather rapidly compared with the much more expensive, but durable 3M technology. Texas Instruments invented the thermal print head in 1965, and the Silent 700, a computer terminal with a thermal printer, was released in the market in 1969. The Silent 700 was the first thermal print system that printed on thermal paper. During the 1970s, Hewlett-Packard integrated thermal paper printers into the design of its HP9800 series desktop computers, and integrated it into the top of the 2600-series CRT terminals as well as in plotters. In the 1970s and early 1980s, Japanese producers (such as Ricoh, Jujo, and Kanzaki), using similar dye-based chemistry, formed partnerships with barcode printer manufacturers (such as TEC, Sato, and others) and entered the emerging global bar code industry, primarily in supermarkets. U.S. producers such as Appleton (NCR's licensee), Nashua Corporation, Graphic Controls, and others fought to gain market share. Leading pressure-sensitive label producers such as Avery Dennison became major consumers of direct thermal paper for label applications. In the late 1980s and early 1990s, thermal transfer, laser printing, electrophotography, and, to a lesser extent, ink jet printing began to take away industrial and warehouse barcode applications due to better durability. Direct thermal made a strong comeback with point of sale receipts (gasoline pumps, cash registers, rental car receipts, etc.). During 1998, Nintendo used thermal paper technology for their Game Boy Printer. In 2006, NCR Corporation's Systemedia division introduced two-sided thermal printing technology, called "2ST" 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「thermal paper」の詳細全文を読む スポンサード リンク
|