Pressure-sensitive recording paper

This paper changes color in response to pressure, similar to that of a pen, for recording information. It is widely used for creating multiple handwritten or typewritten documents, such as slips, and is also used in line printers. There are two main types of pressure-sensitive recording paper: one in which carbon wax is evenly applied to the back of the paper, which is then placed on top of the paper to be copied and pressure is applied from above to cause the color to transfer; and another in which pressure destroys the microcapsules and chemically causes the color to change. The latter type is called non-carbon paper, and has microcapsules on the back of the paper that contain oil in which a colorless reduced form of a dye (leuco dye) has been dissolved, and the surface of the paper to be copied is coated with acidic activated clay, or an organic dye developer based on phenol or zinc salicylate. When the capsules are destroyed while the microcapsule layer and developer layer are in contact with each other, the dye moves to the developer layer and changes color. When a large number of copies are required, paper with a capsule layer and developer layer on both sides is used as the intermediate paper.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

筆圧程度の圧力に感じて発色して情報記録を行うための紙で，伝票など手書きまたはタイプ書きの書類の複数作成に広く用いられるほか，ラインプリンターなどにも応用されている．おもな感圧記録紙には，紙の裏面にカーボンワックスを均一に塗布し, 被複写紙と重ねて上から圧力を加えると転移する形式のものと，圧力でマイクロカプセルを破壊し，化学的に発色させる形式とがある．後者はノンカーボン紙またはノーカーボン紙といい，紙の裏面に無色の色素の還元体(ロイコ色素)を溶解したオイルを含有するマイクロカプセルを塗布し，被複写紙表面に酸性の活性白土，あるいはフェノール系やサリチル酸亜鉛系の有機顕色剤を塗布してある．マイクロカプセル層と顕色剤層が接触した状態でカプセルが破壊されることによって，色素が顕色剤層に移動して発色する．多くの複写枚数を必要とする場合には，カプセル層と顕色剤層を両面にもつ紙を中間紙として使用する．

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