GB955542A - Improvements in or relating to offset printing machines - Google Patents

Abstract

955,542. Printing apparatus. W. RITZERFELD, and G. RITZERFELD. Nov. 15, 1962 [Nov. 23, 1961], No. 43233/62. Heading B6C. An offset lithographic printing machine comprises a main cylinder 1 having a peripheral segment carrying a printing master sheet 2 and a peripheral segment provided with grippers 4 for holding a copy sheet 5 to be printed, an offset roller 18 provided with a fixed apron 24 or other transfer means on one peripheral segment and a peripherally movable apron 25 on another segment, means being provided for transporting the apron 25 into and out of the interior of the roller 18 in a line-wise or section-wise manner whereby to effect the said peripheral movement and to enable selected parts of the image on the apron 25 to be printed, and electromechanical or mechanical means for controlling co-operation of the roller 18 with the cylinder 1 so that after engagement of the roller with the cylinder for transfer of the text of the master 2 on to both aprons, on each successive revolution of the cylinder the roller cooperates with the sheet 2 or by means of the apron 24 whereas the offset roller cooperates with the sheet 5 on each successive rotation of the cylinder by means of the apron 24 and also by a selected part of the apron 25. The apron 25 is unreeled from the shaft 26 and wound up on the shaft 47. The shaft 19 of the roller 18 is mounted between a pair of angular levers 48 which are pivoted at 49 and swinging of the roller 18 is controlled by energization of electromagnets 52, the armatures 51 of which are connected to said levers. Mechanical means such as cams or eccentrics may alternatively be used. The apparatus is controlled electrically by a switching arm 56 which rotates in synchronism with the cylinder 1. Initial energization of the electromagnets 52 swings the roller 18 against the cylinder 1 and the heading portion of the image is received on the apron 24 and the rest of the image on the apron 25. When the arm 56 reaches contact 72, Fig. 1, the roller co-operates with the cylinder 1 to print the heading from the apron 24 and on reaching contacts 74 and 75 the roller co-operates with the cylinder to print the first two lines from the apron 25, assuming the corresponding keys on a switchboard, Fig. 4, not shown, have been pressed. When the arm 56 reaches the contact 80 the heading is transferred to the fixed rubber apron 24. The said switches also cause electromagnets to introduce cam members 42 1 and 42 2 into the path of a pawl 37, Fig. 2, and the apron 25 is moved by an amount equal to two lines of text by means including pawls 34 and 37, a transport wheel 31 and a torsion spring 32. On subsequent rotation of the arm 56 the heading and then lines three and four of the text are printed. Both aprons are cleaned by a washing device 81, 82, 83 and 84. Moistening mechanisms 7, 8, 9, 10 and 11, 12, 13 and an inking mechanism 14, 15, 16 and 17. Whole page duplication may be achieved by cancelling all keys and closing a bridging switch.