GB1125213A - Brush-type moistening mechanism for a lithographic printing press - Google Patents

Abstract

1,125,213. Dampening apparatus for lithographic press. MIEHLE - GOSS - DEXTER Inc. 19 June, 1967 [24 June, 1966], No. 28096/67. Heading B6C. A dampening system for a lithographic printing press comprises a fountain roller carrying a brush, a deflector blade assembly having a plurality of deflector blades arranged side-byside to progressively bend the bristles of the brush and flick water droplets from the tips of the bristles to a drum arranged closely adjacent in the path of the droplets, and means for individually adjusting the position of the blades and their penetration of the brush. Figs. 1 and 3 illustrate a press wherein a lithographic plate 11 carried on plate cylinder 12 is dampened by water-forme roller 35 in contact with a drum 31 having a hydrophilic surface; water is taken from a pan assembly 25, in which the constant level of water 26 is maintained by input 27 and overflow 28, by means of fountain roller 15 carrying a brush 16 whose bristles are deflected by blade assembly 30, thus flicking water on to the surface of drum 31. The bristles of the brush are preferably formed of resilient fibres which are sufficiently stiff as to eject water particles on straightening out; they are arranged on the roller in a narrow helical row, the pitch of the resulting helical brush being less than the width of the narrowest blade in the assembly 30. The assembly is made up of a plurality of blade sections 41 mounted on a common shaft 42; each deflector section 41 carries a blade (45) secured to a yoke (46) which in turn has an associated reference member (50) secured to the shaft 42 with an adjusting screw (53) interposed between the yoke and the member (50), thus adjusting the angle of the blade with respect to the bristles (Fig. 4, not shown). In operative position, the blade is generally tangential to the tips of the bristles; the deflector blades can be rocked collectively to a retracted position away from the bristles by means of arm 80 attached to shaft 42; this manually operated arm halts the damping progress by stopping transfer of water from roller 15 via brush 16 to drum 31 without altering the alignment of the blades (45) with respect to each other. Any droplets of water which escape from between bristles 16 and drum 31 are collected in an extension piece 75 of the fountain pan 25.