The PLS Plate Scanner for the Baker Perkins Press

The Tobias PLS plate scanner was incorporated into the Baker Perkins web press Instascan system. The approach emphasized the overall system concept requiring the close cooperation of the engineers involved with the plate scanner, the press and the printing operation. The plate scanner reads the image coverage of the plate corresponding to each key zone. It corrects for the effect of roller oscillation, and produces key setting values as the result of a non-linear function. This result is printed out on a 2000 char/sec printer and is also sent to a magnetic card encoder. For each plate, a magnetic card encoder. For each plate, a magnetic card is read at the press console, resulting in automatic adjustment of the keys on the appropriate fountain. The makeready waste and time were reduced to the approximate requirement for reaching the running ink/water balance and proper register.