Patent ID: 8017177

Claim:
A method of automatically marking an article which is transferred in one direction, comprising the steps of: storing in advance a pattern for coloring an outer surface of the article with a plurality of coloring agents of respective colors different from each other; detecting a transfer speed of the article with a pair of rotors; outputting a pulse signal from the rotors to a pulse count circuit; counting a number of the pulse signals with the pulse count circuit; supplying the coloring agents; supplying pressurized gas into a coloring agent supply source; spouting a plurality of the coloring agents of respective specific amount, as a single drop at a time, to form aligned spots on the outer surface of the article, from a plurality of separate and spaced nozzles, for each respective color, arranged in a longitudinal direction of the article being transferred, each nozzle having a separate coloring agent supply source connected therewith and a valve disposed between the nozzle and the coloring agent supply source and connected to the pulse count circuit, toward the outer surface of the article according to the pattern in response to a signal from the pulse count circuit; and forming round spots in a plan view on the outer surface of the article, wherein the coloring agents, as a single drop at a time, are spouted toward the outer surface of the article with the aid of bias of the supplied pressurized gas.