| 摘要 |
PURPOSE:To obtain an inexpensive device which requires no optical system, by dividing plural light sources into at least two systems, turn-on-controlling in order at every system, and measuring an area of a scanning part in each area on a printing plate partitioned in the direction being parallel with the printing direction. CONSTITUTION:A scanning head 5 is placed in parallel with a band-like area 3, and also so that overall length of the band-like area 3 is covered by plural photodetectors 10, 10-, also a printing surface 2 of a PS plate 1 is scanned in the direction meeting at right angles with the band-like area 3 by the scanning head 5, and a printing area of each band-like area 3, 3- corresponding to inkpots 4, 4-is measured. That is, the printing area is measured by moving the scanning head 5 relatively against the PS plate in the direction meeting at right angles with the band-like area 3 of the PS plate 1, receiving the diffused reflection light from the printing surface of the PS plate 1 by each photodetector 10 at some time point, and subsequently, receiving the diffused reflection light from the printing surface 2 by each photodetector 10 at a time point the head has moved by width P. |
