Screen printing apparatus

Claim 1

A PRINTING APPARATUS FOR PRINTING ON A SHEET OF POROUS MATERIAL COMPRISING (A) A SUBSTANTIALLY HORIZONTALLY EXTENDING STENCIL SCREEN HAVING PERVIOUS PORTIONS, (B) A COLORING COMPOSITION ON THE TOP OF SAID PERVIOUS PORTIONS, (C) MEANS FOR SUBSTANTIALLY HORIZONTALLY RECIPROCATING SAID SCREEN THROUGH (1) A PRINTING STROKE AND (2) A RETURN STROKE, (D) A PERORATED, ARCUATE-SHAPED SUPPORTING PANEL DISPOSED BENEATH SAID SCREEN, (E) MEANS FOR OSCILLATING SAID PANEL AROUND THE RADIUS OF THE ARCH THEREOF THROUGH (1) A PRINTING STROKE (A'') DURING MOVEMENT OF SAID SCREEN THROUGH SAID FIRST-MENTIONED PRINTING STROKE (B'') IN THE SAME GENERAL DIRECTION AS THE MOVEMENT OF SAID SCREEN, AND (C'') IN POSITION TO PROGRESSIVELY PRESS SUCH A SHEET AGAINST THE LOWER SIDE OF SAID SCREEN, AND (2) A RETURN STROKE (A'') DURING MOVEMENT OF SAID SCREEN THROUGH SAID FIRST-MENTIONED RETURN STROKE, AND (B'') IN THE SAME GENERAL DIRECTION AS THE MOVEMENT OF SAID SCREEN, (F) MEANS FOR HOLDING SAID SCREEN IN UPWARDLY SPACED RELATION TO SAID PANEL DURING SAID RETURN STROKE, AND (G) MEANS FOR APPLYING REDUCED PRESSURE TO THE BOTTOM OF SAID PANEL AND THEREBY TO THE SIDE OF SAID SHEET REMOTE FROM SAID SCREEN DURING SAID PRINTING STROKE, (H) SAID LAST-NAMED MEANS BEING (1) THE SOLE PRESSURE MEANS FOR CAUSING SAID COLORING COMPOSITION TO BE DEPOSITED ON SAID POROUS SHEET, AND (2) DISPOSED IN POSITION TO APPLY SAID REDUCED PRESSURE AT ANY ONE TIME TO ONLY A SMALL FRACTION OF THE ARCH, OF SAID PANEL.