| 摘要 |
PURPOSE:To reduce a power consumption and to solve the problem of a temperature drift, by a method wherein a lamp is lighted for a short time when a measuring switch is turned ON, measurement is conducted in a plurality of time meanwhile, and an average value is found therefrom to be taken as a reflection density. CONSTITUTION:A lamp 21 illuminates the surface of a substance 22 to be measured, and light is reflected and falls on a photosensing element 26. Reference light is obtained by introducing light from the lamp directly to a photosensing element 28. The reflected light and the reference light are measured to calculate the reflection density of the substance 22. When a measuring switch 13 is turned ON, the lamp 21 is lighted for a prescribed time, the measurement of the reflected light and the reference light is conducted in a plurality of times during this lighting, and a plurality of measurement data thus obtained are averaged to determine a measured value of the substance 22 to be measured. This measured value is calibrated with correction data found in a zero point correction mode, and this calibrated measured value is displayed digitally as the reflection density of the substance 22 on a display panel 11, while a buzzer 42 is driven to represent the completion of the measurement with a sound. |
