| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a well practical answer sheet writing utensil for eliminating labor for repetitively marking the same position as in a pencil or a mechanism pencil and erasing it without producing the erasing debris of an eraser while using a sensor for accurately reading an answer sheet, and to provide its set. <P>SOLUTION: The writing utensil for marking on an answer sheet includes at least (1) an electron releasing near-infrared absorbing organic compound, (2) an electron accepting compound, and (3) a reaction medium for controlling the color reaction of (1) and (2), uses a reversibly heat discoloring near-infrared absorbing composition to be color-changed from a coloring condition into a colorless condition with heating, as coloring agent, and has a friction member. The answer sheet writing utensil set comprises the answer sheet writing utensil using the reversibly heat discoloring near-infrared absorbing composition as the coloring agent, and a friction body. <P>COPYRIGHT: (C)2009,JPO&INPIT |
