REPROGRAPHIC APPARATUS CAPABLE OF REPRODUCING VARIOUS TONE AND LINE ORIGINALS AND METHODS OF OPERATION THEREOF

摘要

A method of reproducing a mixed content original (e.g. one comprising half-tone and printed matter) comprises operating a recording device according to a selected one of a plurality of different algorithms. The algorithm used is selected according to the rate of change of reflectance or transmittivity of the zone being reproduced. In the example two reference values are established to define three ranges and the instantaneous value of the rate of change is compared therewith to determine in which of the three ranges it lies. For one range the currently operating algorthm is maintained, for a second range one algorithm is used and for the third range a second algorithm is used. The Figure shows facsimile apparatus comprising a a threshold switch 7 which determines which range contains the instaneous value of the rate of change. The switch 7 provides an output to the threshold devices, 15, 17 which determine the mode of operation of the recording device (printer) 19.