An improved electrocoagulation printing method comprising the steps of (a) providing a positive electrode formed of an electrolytically inert metal and having a continuous passivated surface moving at substantially constant speed along a predetermined path, the passivated surface defining a positive electrode active surface; (b) forming on the positive electrode active surface a plurality of dots of colored, coagulated colloid representative of a desired image, by electrocoagulation of an electrolytically coagulable colloid present in an electrocoagulation printing ink comprising a liquid colloidal dispersion containing the electrolytically coagulable colloid, a dispersing medium, a soluble electrolyte and a coloring agent; and (c) bringing a substrate into contact with the dots of colored, coagulated colloid to cause transfer of the colored, coagulated colloid from the positive electrode active surface onto the substrate and thereby imprint the substrate with the image. The improvement resides in applying between steps (b) and (c) on the positive electrode active surface a liquid olefinic substance to dislodge any remaining ink from the surface without altering the dots of colored, coagulated colloid, and removing the dislodged ink in admixture with the olefinic substance from the positive electrode active surface, thereby preventing formation of undesirable background on the printed image in step (c).
