US 4,552,165 A · Method and device for maintaining density of a printed color constant

Abstract

In a system for maintaining density of a printed color constant, a reading unit is connected with a unit measuring the reading signal. An amplitude measuring unit and a rated variable voltage source are connected with a comparator. The comparator is connected with a PID regulator, the signal of which is connected with a first adder which itself connects with a viscosity code setting potentiometer. The first adder is connected with a second adder connected to a viscosimeter. The signal produced by the second adder is sent to an amplifier connected with a command circuit for controlling mixer valves for ink and solvent. This command circuit can be locked or released by means of signals received from a level indicator in a tank. The command circuit also actuates a pump and a valve of a return circuit of the ink/solvent mixture. The system is employed for controlling and keeping constant color density of a print.

Claims8

Dependent claims

A method for keeping constant density of a printed color on a medium, comprising the steps of:

receiving light rays reflected by a printed mark on the medium;
transmitting the reflected light rays to a photodiode to generate a signal corresponding to their intensity and thus representative of the density of the printed color;
measuring an amplitude of the signals and comparing a resulting measured value with a reference value to provide a correction signal;
combining the correction signal with a viscosity code signal indicating a viscosity code of an ink/solvent mixture used for printing on the medium in order to generate a corrected viscosity code signal;
combining the corrected viscosity code signal with a viscosity measuring signal derived from viscosity measurement of the ink/solvent mixture in order to provide an error signal;
and
using the error signal to command opening or closing of valve means of a mixture for regulating the ink/solvent mixture.

4 more elements

A system for keeping constant density of a printed color on a medium, comprising:

means for receiving light rays reflected by a printed mark on the medium;
means for transmitting the reflected light rays to a photodiode to generate a signal corresponding to their intensity and thus representative of the density of the printed color;
means for measuring an amplitude of the signals and comparing a resulting measured value with a reference value to provide a correction signal;
means for combining the correction signal with a viscosity code signal indicating a viscosity code of an ink/solvent mixture used for printing on the medium in order to generate a corrected viscosity code signal;
means for combining the corrected viscosity code signal with a viscosity measuring signal derived from viscosity measurement of the ink/solvent mixture in order to provide an error signal;
and
means for using the error signal to command opening or closing of valve means of a mixture for regulating the ink/solvent mixture.

4 more elements

Dependencies are inferred from the claim text.

Method and device for maintaining density of a printed color constant

Life of this patent

Method and device for maintaining density of a printed color constant

Life of this patent

Abstract

Claims8