Patent GB-772711-A (GB)
Title: Improvements in or relating to squeegees for screen and stencil printing
Inventor: GROAK JOSEF
IPC: B41L13/04
Filed: 1951-06-15
Abstract: 772,711. Stencil or screen printing. CHAMBON, Ltd. May 30, 1952 [June 15, 1951], No. 14293/51. Class 100(2) In screen or stencil printing, the ink is applied through the screen by a squeegee having in its surface ink-carrying recesses arranged in succession in the direction of the relative movement between the screen and the squeegee. The squeegee may be in the form of a blade, roller, segment, flat disc, or endless band and may be of resilient or rigid material, and the recesses may be straight, zigzag, or helical grooves running longitudinally or axially of the squeegee e.g. formed by blades mounted radially on a shaft, or may comprise indentations of square, circular or L shape. Moreover, the inks employed may be of semi-liquid composition comprising thermoplastic materials solid at ordinary temperatures so that with a thick stencil a relief printing may be obtained e.g. for Braille. In one form of machine described, Fig. 6, for printing on a paper web 12, the squeegee is a roller 53 with axially extending grooves set at an angle to the axis and engaging the internal surfaces of two stencils mounted on a cylinder 11. The roller 53 is in contact with a fountain roller 54 and a doctor roller 56, the latter having a doctor blade 57 applied thereto which is adjusted by a series of screws 61. Brackets 62 carrying the inking assembly are mounted on a hollow fixed shaft 38 within which is situated the shaft 22 of the stencil cylinder. The drive to the rollers is from a gear 65 on the shaft 22, an opening in the shaft 38 permitting of this. A second and identical printing cylinder 10 may be mounted on the other side of the web 12 either exactly opposite the cylinder 11 as shown or spaced therefrom in the direction of web feed. The bearing blocks of the cylinders are slidable and the cylinders at their ends have rollers engaging cam tracks whereby the cylinders are separated when the spaces between the ends of the stencils are at the printing position. The cylinders may be separated manually if desired. In a modification, Fig. 8 (not shown), the squeegee roller is hollow and rotates on a fixed hollow shaft to which ink is supplied under pressure. The ink flows through a radial channel in the shaft and radial ducts in the roller to the grooves in the roller. In another form, Fig. 9, the screen 90 is flat and is carried by a bed 94 reciprocated from a shaft 98 through rack- and-pinion gearing 95, 96, 100. The grooved squeegee roller 91 which is fed with ink from a duct by a duct-roller, presses against the lower side of the stencil, and sheets to be printed are fed to a cylinder 92 on the upper side of the stencil. The bearing blocks 104, 105 of the roller and cylinder are connected by toggle links 106 and pressed towards each other by springs 108. At the end of the printing stroke of the stencil, a lug 109 engages the links 106 to straighten them and thus move the roller and cylinder apart. Similarly at the end of the non-printing stroke of the stencil, a lug 110 moves the links 106 in the reverse direction to allow the cylinder and roller to press against the stencil. Specification 683,800 is referred to in the Provisional Specification.