| 摘要 |
PURPOSE: To enhance the intensity of light emission from image information and to enable reading with good SN ratio by printing image information on the surface of a label with fluorescent ink, mixing a specified fluorescent pigment into the label, and exciting the fluorescent ink with light emitted from the fluorescent pigment. CONSTITUTION: The label sheet 29 consists of labels 38 arranged with a specified interval on a release base sheet 39. The label 38 is produced by applying an adhesive on the lower surface of a transparent film 381 to form an adhesive layer 382, forming a coating layer 383 on the upper surface of the film 381, and adhering the adhesive layer 382 to the release base sheet 39. A bar-code is printed with a fluorescent ink on the surface of the coding layer 383. The coding layer 383 contains a fluorescent pigment. As for the fluorescent pigment, such a pigment that emits light of wavelengthλG satisfying the relation ofλI>λG is used.λI is the wavelength of light emitted from the fluorescent ink. Therefore, when the fluorescent ink is irradiated with external light, it directly emits light due to the external light, and moreover, it is excited by the light emitted from the fluorescent pigment by irradiation of light. Thus, intensity of emitted light is increased.
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