| 摘要 |
PURPOSE:To facilitate the detection of a speed difference of moving bodies with a simple device by making a laser light reflect on the first and second moving bodies sequentially to compare respective frequency changes by a Doppler effect. CONSTITUTION:When a laser light 41 from a laser light source 31 is made to irradiate a specified part P1 of the surface of a plate cylinder 11 rotating at an angle A of incidence radially askew from the rear in the direction of movement thereof,. the main reflected light 42 of the laser light 41 reflected scattering on the surface of the plate cylinder 11 irradiates a specified part P2 of the surface of a blanket cylinder 12 rotating at the angle A of emission askew from the front in the direction of movement thereof. So, the frequency of the laser light 41 generated at the light source 31 and frequency changes by a Doppler effect of the reflected light 43 received 31 are measured and a speed difference is calculated between surface speeds of the plate cylinder 11 and the blanket cylinder 12 based on the wavelength of the laser light 41 and the angle A of incidence set. |
