Patent GB-757020-A (GB)
Title: Improvements in or relating to a rotary duplicating machine
IPC: B41C1/10
Filed: 1953-08-06
Abstract: 757,020. Lithographic duplicating machines. RITZERFELD, W., and RITZERFELD, G. Aug. 6, 1953 [Aug. 6, 1952], No. 24464/55. Divided out of 756,949. Classes 100 (1) and 100 (2). A duplicating machine for direct printing with the lighographic master sheet prepared as described in Specification 756,949, comprises a printing cylinder 14, Fig. 1, to which the master sheet 1 is attached by grippers 15, 16, operated as described below. Damping and inking arrangements.-Two liquid-applying felts 26, 89 mounted in pivotal boxes 24, 87 are displaceable to engage the cylinder 14 by means of springs 29, 92 and are normally held out of engagement by levers 27, 90 having rollers engaging the edges of links 35, 94. These links have sliding engagement with fixed pins 36, 95 at one end and are pivoted at the other end to a control lever 31. Displacement of the lever causes the rollers to enter notches in the links and allow the felts to engage the printing cylinder for the purposes described below. A moistening roller 41 mounted on a lever 38 is similarly controlled by a link 42 connected to an extension from the operating lever 31. A similar link 74 cooperates with a roller 76 on a lever 61 pivoted at 60 and forming one side of a frame mounting a number of inking rolls 62-66 receiving ink from a reservoir 72. A pump 48, the piston 57 of which is actuated by a lever 55 engaging a cam 53 on the printing cylinder, pumps moistening liquid, e.g. water, from a reservoir 47 to the moistening roller 41 and felt 26 through a manually-operable selector valve, e.g. a two-way valve 52. The lever 31 when operated also serves to rotate an eccentric 21 connected by links 19 to the arms 18 supporting the impression cylinder 17, which is thereby displaced into engagement with the printing cylinder when the lever 31 nears its lowermost position. Feeding sheets.-Sheets are fed to the printing couple by rollers 84, 85 receiving the sheets from a table 83 over which they are forwarded by a roller 81 locked against rotation in one direction and mounted on a bell-crank lever 80 reciprocated by a lever 78 pivoted at 77. A link 79 oscillated synchronously with the rotation of the printing cylinder is adapted to rock the lever 78. The other arm of bellcrank lever 80 co-operates with a curved member 82 attached to the lever 31 so that when this lever is moved to the lowermost position the roller 81 is lowered on to the table to forward the top sheet from a pile of sheets thereon to the rollers 84, 85. The lever co-operates with a notched quadrant 33. Driving mechanism; printing surfaces.-The printing cylinder is controlled by a one-revolution clutch comprising a continuously driven ratchet wheel 97 freely mounted on the axle 13 and a co-operating pawl 100 mounted on a pin 99 fixed to the cylinder. The pawl is normally held out of engagement with the ratchet by a hooked lever 103. When this lever is displaced by manual or pedal-operated means the cylinder rotates until the pawl is again disconnected by abutment with the lever 103, making one complete revolution. The grippers 15, 16 for the master sheet 1 are provided with a series of pins adapted to pass through perforations in the edge of the master sheet. In the starting position (shown) an operating lever 108 for the gripper 15 has one end in abutment with the free end of a lever 106 manually operable to open the gripper. A second pawl operating member 116, displaceable by a lever 113 into the path of the pawl is adapted to stop the cylinder with the gripper 15 in the dotted line position. When member 116 is displaced to this position a link 119 rotates a cam lever 118 the end of which is adapted to engage one end of the gripperoperating lever 122 and cause opening of the gripper 16. Release of the control lever 113 causes the gripper to be closed and the cylinder to continue for the remainder of the revolution. The leading edge of the master-sheet is attached to the cylinder 14 in the starting position by opening gripper 15 by actuation of lever 106, inserting the master-sheet over a table 111 and releasing the gripper. Lever 113 is then moved to the dotted line position and the pawl released by lever 103. After a small rotation the pawl engages member 116 and the cylinder stops with gripper 16 opened. The trailing end of the master-sheet is then tucked in the gripper and the lever 113 returned to its normal position. To protect the greasy image on the master-sheet during storage it is covered by a thin film which is loosened and removed or dissolved away before printing begins. The felt 26 and roller 41 are brought into contact with the printing cylinder for this purpose by an initial displacement of lever 31. Movement of lever 31 to the next notch on quadrant 33 displaces felt 26 to the inoperative position but allows moistening roller 41 to remain in contact with the cylinder. When the mastersheet is suitably moistened the next movement of the lever 31 brings the inking roller 62 into operative position for inking the greasy areas of the master-sheet. Movement of the lever 31 to the final position causes the impression cylinder to engage the printing cylinder and the bell-crank lever 80 to be released from the curved member 82 so that feeding of sheets from the pile on table 83 begins, the sheets being forwarded to the printing couple as described above. When the printing operation with a particular master-sheet is completed the lever 31 is lifted to the second notch position on quadrant 33. This interrupts the inking, moistening and sheet feeding and moves the impression cylinder out of engagement with the printing cylinder. It also causes the felt 89 to contact the master-sheet and apply a thin film of a quick-drying liquid which leaves a protective film so that the master-sheet can be stored without damage.