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Abstract

The invention relates to a printing process and machine which enables the production of two-color images on a print carrier. The machine which carries out this process consists of two applicators (40,42) placed one after the other to deposit two layers of differently colored pigments onto the magnetic drum (10). The surface of the drum has produced thereon a latent magnetic image whose magnetic points have the same intensity of magnetization, but opposite polarities, the magnetic points intended to produce powder-image parts in one of said colors being opposite to that of the points intended to produce the other parts of said image. A transfer station (44,45) is provided with a magnetic field generator (21) located upstream to the point (45) where the pigments are transferred to the print carrier (20). The magnetic-field generator (21) applies a constant magnetic field to the recording surface in a direction perpendicular to the surface. The amplitude (H) and the direction of the magnetic field serves to reduce the intensity of magnetization of the magnetized points intended to produce on the carrier powder image parts whose color is that of one powdery developer and to increase the intensity of magnetization of the other magnetized points. The sole second developer, which has been deposited onto the points whose magnetizations have been increased, is transferred to the print carrier, while the two developers, which have been deposited onto the points whose magnetizations have been reduced, are transferred to said carrier in superimposed layers.

First Claim