Thermal paper is also called thermal recording paper, thermal paper, copy paper, thermal paper is 3 m (MinesotaMiningInkCharacter) companies in the United States first developed in 1951. Thermal paper is a kind of processing paper, the manufacturing principle is in the quality of the base paper coated with a layer of "thermal coating "(thermochromic layer).

1. The use of thermal paper

Thermal paper is mainly used in the following aspects: fax machine, communication, medical, recording and measuring systems such as electrocardiogram machine, thermal instrument, computer networking terminal printing, trademark, label (POS), among which fax machine is the most widely used. With the rapid development of information technology, bill printer technology and bar code technology have been widely used, thermal paper has been rapidly growing because of its unique performance, the advantages of rapid image generation and convenient bar code label, in the field of bar code record information and bill printing.

2, the classification of thermal paper

Thermal paper can be divided into ordinary thermal paper and three thermal paper from the function. Tri-proof thermal paper is a layer of protection on the thermal hair color layer, to give tri-proof thermal paper better waterproof, oil-proof and anti-friction properties, mainly used in the high-end market.

Thermal paper mainly is divided into two categories based on the structure, one is using thermal in assaying the fineness of colored pigment physics, physical type thermal paper records effect, the thermal paper is divided into molten transparent type, melting heat transfer printing and sublimation type, etc., the representative of which is melting transparent type of thermal paper, it is widely used in medical eeg and ecg, etc.; The other is the use of heat under the action of chemical reactions to achieve hair color purpose of the chemical thermosensitive paper, is the largest amount of products on the market at present, this kind of thermosensitive paper is divided into two components of metal compounds hair color thermosensitive paper and colorless dye two-component thermosensitive paper.

3. Thermal paper color rendering principle

Melting transparent thermosensitive paper color rendering principle is in the black base paper, coated with an opaque layer of wax as a surface layer, through the role of the hot pen, opaque waxy material melting transparent, the color of the underlying layer of the base paper revealed and formed an image.

The color developing principle of metallic compound color thermal paper is that heavy metal salt and reductant based on fatty acid are mixed together, and fatty acid salt is melted and reductant is reacted by heating temperature, so that heavy metal is reduced and color developing is free.

Colorless thermal paper coloring principle is based on the colorless dye containing inner fat ring and colorant mixture, under the action of heat, colorant and colorless dye melting reaction and color.

The methods of judging thermal paper

1. Fire roast method is very simple, with a lighter heating on the back of the paper, if after heating, the paper is now out of brown color and specification thermal formula is not very reasonable, save the time may be more short, if the paper is on the black part with thin stripes or uneven color piece, means it is unevenly coating.

Better quality paper in the heat should be black mixed green (with a little green), and color block uniform, from the center to the surrounding color gradually faded.

2. Sun exposure contrast identification

Compare and identify the paper that will be printed with a highlighter and put it in the sun (this can accelerate the reaction of the thermal coating to light), which paper will turn black the fastest, indicating the shorter the storage time.