| 摘要 |
PROBLEM TO BE SOLVED: To provide a paper quality detection apparatus capable of simply detecting the quality of paper in a non-contact state. SOLUTION: A light source 1 generating light of frequency f1 and a light source 2 generating light of frequency f2 are provided and the frequency f3 of the difference between the frequencies f1, f2 of lights is set to 1-10 THz. Paper 4 is irradiated with the lights from the light sources 1, 2 through a heterodyne crystal 3 and a light signal only of the frequency f3 transmits through the paper 4 to be sensed by a photosensor unit 5 to be converted to an electronic signal. A CPU unit 6 takes in the electric signal to convert the same to digital data and fetches the temperature data and humidity data measured by an environment sensor 11 to collate the digital data, the temperature data and the humidity data with a preliminarily held map to judge the quality of the paper 4. |
