| 摘要 |
PURPOSE:To measure quantitatively the area ratio, etc., of part of a position to be measured where ink is transferred completely and specular reflection is performed with high accuracy by arranging at least one main light receiving element at the place to be measured in the same plane and at the same angle with a light emitting element. CONSTITUTION:The light emitting element 22 emits a measurement light beam toward the position of a sample 16 where a measurement is taken, the main light receiving element 23 is arranged at the position to be measured in the same plane with the element 2 so that an angle theta1 of incidence and an angle theta2 of reflection are equal, and a subordinate light receiving element 24 is arranged at a different position from the element 23. Then, the element 23 is irradiated with light having illuminance proportional to the area of part of the position to be measured where ink is transferred completely almost to cause specular reflection. Simultaneously, irregularly reflected light from due to aggregation destruction, etc., as a noise light component and irregularly reflected light from the paper surface of the lower layer of the part where the ink is transferred completely are also projected with low illuminance. The element 24 is irradiated with only various irregularly reflected light beams which become noise components. Therefore, noise components in the output of the element 23 are removed by multiplying the output of the element 24 by a constant factor and subtracting it. |
