US 4,541,336 A · Method and device for controlling the supply of ink to the inking units of a multi-color printing press

Abstract

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.

Claims22

Dependent claims

A method for controlling the rate of supply of printing ink to a printed product passing through a multicolor printing press in separate zones spaced across the width of the press, comprising the steps of:

directing light from a light source to a material printed on the product in at least one zone at a time;
sensing the light reflectance from the material printed on the product in each zone to which light is directed;
converting the sensed light reflectance into a signal having acoustic frequencies dependent on the level of different optical frequency components of the sensed light;
providing a division of the complete acoustic frequency spectrum into a desired member of frequency sub-ranges, and arranging the converted acoustic frequencies into frequency sub-ranges related to the intensity of the ink colors used;
and
generating servo signals from the frequency sub-ranges for adjusting the printing ink supply across the width of the press.

3 more elements

A device for controlling the rate of supply of printing ink to a multi-color printing press having:

a plurality of inkings units each including means for changing the rate of inking in separate zones spaced across the width of the press;
and
at least one unit for examining the ink in an area of printed product passing through the press, said area having been printed in one of said zones, the unit comprising:
a light source for directing light onto the printed product;
a light transducer for sensing the light reflectance of the light from the printed product area and generating a signal or a function thereof;
an acoustic sensor connected to the light transducer for detecting the signal generated by the light transducer and converting the detected signal to an acoustic signal.
an acoustic receiver connected to the acoustic sensor for receiving the acoustic signal output from the acoustic sensor and producing a frequency band output signal;
variable frequency filter means connected to the acoustic receiver for receiving the frequency band output signal from the acoustic receiver, converting the frequency band output signal into a desired number of sub-bands and producing an output signal representative of each sub-band;
and
evaluating means connected to the variable frequency filter means for receiving the output signals from the variable frequency filter means and converting said output signals into servo signals applied to the inking units for adjusting the inking rate across the width of the press in the zones.

7 more elements

Dependencies are inferred from the claim text.

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

Life of this patent

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

Life of this patent

Abstract

Claims22