Patent GB-753182-A (GB)
Title: Improvements in or relating to duplicating apparatus
IPC: B41L19/00
Filed: 1954-07-14
Abstract: 753,182. Rotary printing machines. ADDRESSOGRAPH-MULTIGRAPH CORPORATION. July 14, 1954 [March 25, 1954], No. 20599/54. Classes 100 (1) and 100 (2). A rotary offset duplicating machine comprises a plate cylinder 30, Fig. 3, carrying a printing plate 27, an offset cylinder 32, an impression cylinder 31, first and second inking rollers 25, 26 for applying ink to different areas of the printing plate 27, means for rendering the inking rollers individually active or inactive as desired, driving means for the cylinders and for a control mechanism adapted to render the first inking roller operative and the second inoperative for a predetermined number of cycles of rotation of the cylinders and then render the first inking roller inoperative and the second operative for a further predetermined number of cycles. The cylinders 31, 32 are mounted between side plates 17 and the plate cylinder 30 is carried on side plates 19 pivoted to plates 17 at 20. The spindle 21 of cylinder 30 has eccentric end portions connected by links to the plates 17 so that rotation of the spindle will cause the plate cylinder to swing into and out of contact with the offset cylinder 32 by angular displacement of side-plates 19. The bearing spindles 40 of the inking rollers 25, 26 also have eccentric end portions which engage in sideplates 19 and, by rotation cause the rollers to be moved into and out of contact with the printing plate 27. Operating levers 38 and 42, Fig. 2, are attached to spindles 21 and 40, these being rotatable manually or by a control mechanism described below. Ink repellent is applied to the printing plate by roller 28. Feeding sheets.-A sheet separating mechanism 15 is provided similar to that described in Specification 630,363 for feeding " run-down " sheets from a pile A. These sheets are used to clean the ink from the printing plate and offset cylinder before the other inking roller is brought into use to print from another part of the printing plate. A suction gripper 60, supplied from a motor-driven pump through a pipe 73 is mounted on a swinging cam-actuated arm 62 the arrangement being such that the top sheet of the pile is lifted and entered between forwarding rollers 55, 56, the suction then being cut off. Moving bands 85 carry the sheet to the printing position between cylinders 31, 32, suitable registering means being provided. The arm 62 carrying the suction gripper may be retained in the raised inoperative position by a slider 80, Fig. 2, having a nose 82 engageable under the moving end of arm 64. The slider is operated manually by a handle 81 or automatically by the control mechanism described below. Sheet delivery.-The " run-down " sheets which are fed automatically and copy sheets, fed manually, are both collected in a receptacle 45 but are received in separate compartments 90, 91. The compartments are separated by a plate 95 pivoted at 96 and displaceable into and out of alignment with a stripper 49 guiding the sheets as they pass out of the printing couple. The plate 95 is moved to guide the sheets into the upper or lower compartments by a lever 101, Fig. 6, pivoted to the wall of the receptacle at 102 and having a slotted limb 104 at right angles co-operating with a pin 106 on a lug attached to plate 95. The lever is connected at 100 to the armature of a solenoid 97 which, when energized moves the plate 95 into the uppermost position against the action of a spring 109. The solenoid is supplied through a switch controlled by the control mechanism now described. Control mechanism.-A shaft 111, Fig. 2, rotatable by a handle or by a drive from the impression cylinder 31 is connected by pulleys and a belt 114, Fig. 9, to a shaft 115 adapted to be coupled by a clutch 118 to an aligned shaft 117. The clutch is controlled by a lever 120 (see also Fig. 2) connected to it by a link 119. Shaft 117 is connected by a belt 124 to a shaft 123 which drives, through a reduction gear in gear-box 122 a control shaft 121. The ratio of the reduction gear is variable. The shaft 121 carries at one end a cam 141 acting through a spring-loaded follower lever 151 to control a switch 157 connected to energize the solenoid 97. A red lamp 140 (Fig. 2) connected in parallel with the solenoid, lights when switch 157 closes. A series of cams 142-145 and 134 are mounted on shaft 121 and co-operate with levers 152- 154, 175 and 136 pivoted on a parallel shaft 137. Of these cams, cam 134, Fig. 7, serves to control the switch 132 energizing the driving motor of the machine. In order to start the machine, a hand lever 125 is pulled anticlockwise against spring 170, a link 128 on lever 125 being connected by pin-and-slot 179, 180 to a similar lever 129 having a lug 130 adapted to operate the switch 132. A latch 138 pivoted to lever 136 is normally connected by a pin 183 to lever 129, the pin normally seating in a recess in the upper wall of a slot 185 in the latch. When lever 125 is moved in either direction cam surfaces 181, 188 on link 128 bear on coacting surfaces on the latch 138 and lift it to free pin 183 from the recess so that lever 129 can be moved without moving lever 136. As soon as the switch is closed the cam 134 rotates to displace lever 136 anticlockwise so that the latch 138 returns to its position of engagement with pin 183 whereby the cam 134 again controls the lever 129. Normally the cam 134 causes the switch 132 to re-open at the end of the pre-determined number of cycles of the printing cylinders but, by clockwise rotation of lever 125 the switch may be re-opened at any time before that. As shown in Fig. 17, the cams 142-144 act on followers 148 on levers 152-154, the levers being connected at their free ends to links 162- 164 controlling the mechanisms described above. The connection is made by a pin 196 engaging in a slot 195 so shaped that when the ends of the links are lifted the automatic control is disconnected and manual control may be used. As shown in Fig. 2, the link 162 (governed by cam 142) is connected to slider 80 which renders the sheet separating device active or inactive. Link 163 (governed by cam 143) is connected through an arm 173 to the spindle 21, rotation of which causes the plate cylinder to move into and out of contact with the offset cylinder. A link 164 (governed by cam 144) is connected to the spindle 40 of the upper inking roller 25 which is thereby moved into inking contact with the printing plate 27. Lever 175 (Fig. 9) governed by cam 145 is connected by a link 165 to control the lower inking roller in the same way. Inking rollers.-As shown in Fig. 19 the inking roller 25 may be a complete roller adapted to ink the whole of the printing plate 27 while the roller 26 is cut away so as to be adapted to ink only a part of plate 27. In this case the sheets printed when roller 25 is in operation will reproduce the whole of the printing plate and those printed with roller 26 will reproduce only a part, either the top or bottom of the master or the right or left hand side depending on the disposition of the plate on the cylinder. Alternatively both inking cylinders may be cut away so that both effect inking of only a part of the master. The two inking rollers may supply different colours. Operation.-When it is required to print copy sheets from a printing plate, some copy sheets bearing one part and the others bearing another part of the plate, the plate is attached to cylinder 30 and the machine is started by actuation of lever 125. Rotation of control shaft 121 then automatically causes the receptacle plate 95 to be lifted so that printed sheets are delivered to the bottom compartment, causes the red lamp 140 to light, warning the operator that copy sheets are not to be fed yet, causes the plate cylinder to move into contact with the offset cylinder, sets the sheet separator 15 in action, so that " run-down " sheets are fed to the printing couple and swings upper inking roller 25 into engagement with the plate cylinder. A predetermined number of " run-down " sheets is then passed through the machine to ensure cleaning of the offset cylinder and proper inking of the printing plate. At the end of this period the sheet separator is rendered inactive, the sheet receptacle is re-positioned and the red light is extinguished. The operator then feeds the desired number of sheets manually to the machine, these being printed and collected in the upper part 90 of the receiving tray 45. After this period the inking roller 25 is moved out of operation and the feed of " run-down " sheets is restarted, the receptacle being in its first position and the red light lit. When the inked image on the offset cylinder has been erased and the ink removed from the printing plate the inking roller 26 comes into operation and the process is repeated. After printing with this inking roller the cylinders may be cleaned by passing a few " run-down " sheets through and finally the switch 132 opens to stop the machine. As stated above the lever 125 may be used to stop the machine at any time during the operation described. Also the automatic control may be dispensed with, the clutch 118 (Fig. 9) being uncoupled by lever 120, the links 162-164: being disconnected by lifting handles 198 (Fig. 17) and the driving motor being energized by a switch in parallel with switch 132. The operation of the machine is then entirely manual. Alternatively the sheet feeding mechanism 15 may be disabled alone by operation of the release member 81, the control link 162 being formed, for this purpose, in two parts connected by yielding springs. The invention may alternatively be applied to a direct-printing machine.