Patent ID: 7976906

Claim:
A printing apparatus for printing ink on glass boards, comprising: a horizontal support for a glass board on which ink having solid particles is to be printed; at least one digital ink-jet printing head; and an ink supply system comprising: a main ink tank, a stirrer positioned within the main ink tank, a closed circulation line for circulating the ink out of the main ink tank and back into the main ink tank using a first circulation pump, a mid ink tank, a first ink supply pipe connecting a junction in the closed circulation line to the mid ink tank, and a second ink supply pipe connecting the mid ink tank to the at least one digital ink-jet printing head, wherein the ink supply system is configured to provide the ink from the main ink tank to the least one digital ink-jet printing head through the closed circulation line, the first ink supply pipe, the mid ink tank and the second ink supply pipe to control dispersal of liquid and the solid particles in the main and mid ink tanks, and to maintain the ink provided to the at least one digital ink-jet printing head in a substantially unified heterogenic suspension.