Printer having a measuring unit adjustable to the spectral sensitivity of a copy material

摘要

A printer has a light source and an objective which direct a light beam along a predetermined path, and a unit in the path for measuring the density of a master to be reproduced. The measuring unit includes a filter combination of at least two filters downstream of the objective and a light sensor downstream of the filter combination. The filter combination has a transmission pattern which shifts as the angle of incidence of the light beam on one or more of the filters changes. At least one of the filters is pivotable in order to vary the angle of incidence of the light beam on the same. This allows the transmission pattern to be shifted so as to adjust the measuring unit to the spectral sensitivity of the copy material used for reproduction of the master.