Method and device for controlling the supply of ink to the inking units of a multi-color printing press

摘要

In the operation of a multi-color printing press an accurate and at the same time economic control of the inking of the printing plate or the like is made possible by converting the optical frequencies of light reflectance from inking zones (i.e. the zones controlled by the different fountain keys or the like) of the products printed on the press into representative acoustic frequencies which may be processed by electronic signal processing circuitry. The conversion of the light reflectance (diffusely reflected light from the printed image) into acoustic frequencies is undertaken by a light-pressure transducer with a microphone whose electrical output signal goes to a variable frequency filter means with a scan function such that narrow frequency sub-ranges are produced that are processed spectrally in keeping with the intensity thereof. The resulting intensity signals are related to the inks used in the press and converted into adjustment signals for the operation of ink fountain keys or the like controlling the inking rate is separate zones of the press.