Patent GB-735181-A (GB)
Title: Rotary duplicating machines and methods of printing therefrom
IPC: B41L11/00
Filed: 1950-02-10
Abstract: 735,181. Rotary duplicating machines. RITZERFELD, W., and RITZERFELD, G. Feb. 10 1950, No. 3464/50. Classes 100 (1) and 100 (2). Copying documents; tripping arrangements; feeding sheets; sheet-delivery.-A rotary duplicating-machine is adapted for printing parts of the text of a printing-surface, which parts are separated by more than a line spacing, e.g. a heading and a selected line or lines, in immediate juxtaposition on copy sheets, and for this purpose means are provided for moving the impression cylinder away from the printing cylinder and positively separating the copy sheet from the printing surface during the passage across the printing-line of that part of the printing surface which is not to be printed; the copy sheet may remain stationary during the interval between the printing of the heading and the line or, where a mirrorscript printing- surface is used, may be moved rearwardly for damping that part of the sheet which is to receive the line impression, and then forwardly in readiness for the printing of the line. The machine may be arranged so that the whole of the text may be printed on a single sheet. The arrangement is described as applied to machines employing mirrorscript printing-surfaces and inked printing-surfaces, and of the general type in which the machine is stopped after each revolution to permit a copy sheet to be placed in position preparatory to printing. In one embodiment, Figs. 2 to 4, the sheets are fed over a table 66i<SP>11</SP>, beneath a moistening device 66k and between the impression roller 67e and a spring-pressed roller 67m to the printing line between the roller 67e and a cylinder 67h carrying a mirrorscript original. Means are described (Figs. 18, 18a, not shown) for preventing flexing of the roller 67m. The roller 67e is carried by pivoted levers 67f and is operated by toggle levers 67c, 67d connected by a link 67b to a lever having a roller 67 engaged, once during each revolution, by one of a series of axially-spaced cams 68-77 on a shaft 79 driven from and having the same angular speed as the printing cylinder 67h. Operation of the linkage 67-67d by a cam causes the impression cylinder 67e to be moved into contact with the cylinder 67h to print a part of the text, the particular cam in use determining the length, in the direction of sheet feed, of the part printed. Circumferential adjustment of the cams relatively to their shaft 79 selects the particular part (i.e. line or lines) to be printed. An eccentric pivot 67k for the lever 67c permits of adjustment of the pressure of the impression roller 67e. Prior to its engagement with the roller 67, the selected cam 68 ... 77 acts on a roller 66 to bring the moistening device 66k into contact with the copy sheet. The roller 66 is carried by a lever pivoted to a rod 66b having a pin 66c engaging a slot in a rod 66d and connected by a spring 66e to a pin 66g on.that rod. The rod 66d is pivoted to a lever 66h carrying the moistening device 66k and connected to a weak spring 66f tending to keep it raised. The arrangement causes the moistening device to have yielding engagement with the sheet. Fixed to the shaft 79 are cams 100, Fig. 2, acting on rollers 101, 102 corresponding to the rollers 66, 67 to cause actuation of the impression roller and moistening device through linkages similar to those shown in Fig. 4 for printing the heading prior to the printing of the line or lines. After the heading is printed, the impression roller 67e is moved away from the cylinder 67h and the sheet is positively separated from the printing surface by the roller 67m. The sheet then remains stationary (or is moved rearwardly and forwardly as referred to earlier) while the printing-surface continues its movement, until the impression roller is again moved into contact with the cylinder for printing a line or lines; the selected line or lines are thus printed on the sheet in juxtaposition to the heading. The set of cams 68-77 is secured to a sleeve 85 movable circumferentially and axially of the shaft 79. Attached to the cams is a grooved ring 62b engaged by a finger 62a attached to a block 62 threaded to engage a screwed spindle 61 and guided by a fixed rod 63<SP>1</SP>. Rotation of the spindle 61 imparts axial movement to the sleeve 85 so as to position that cam corresponding, e.g., to the number of lines to be printed, to be positioned opposite the rollers 66, 67. To select the particular line or lines, a gear-wheel 78 connected to manual operating means is fixed to the sleeve 85 for imparting circumferential movement thereto relatively to the shaft 79. Devices are incorporated whereby the cams are stepped backwardly relatively to the shaft 79 during each revolution of the printing cylinder so that successive lines on the printing surface are printed on successive sheets passing through the machine. These devices comprise a stepped plate 63 fixed to the block 62 and an arm 81 fixed to the rod 63<SP>1</SP> engaging a cam 80 on the shaft 79 so that once in each revolution the plate is moved into the path of abutments 92, 94 on two levers 64, 65 freely mounted on a member 98a keyed to the shaft. The steps correspond to the operative lengths of the cams and, since the plate 63 moves in the axial direction with the cams, the step corresponding to a selected cam is positioned opposite the abutments 92, 94. The levers 92, 94 are connected by a spring 93 normally holding them in the relative position shown in Fig. 3. Another spring 90 normally holds the lever 64 with its leading edge abutting against a pen 95 on a disc 91 fixed to the block 98a. A spring-pressed pawl 88 on the lever 64 engages a ratchet-wheel 86 which is fixed to another ratchet-wheel 84 in turn fixed to the sleeve 85. A pawl 82 pivoted on a pin 91<SP>1</SP> on the disc 91 engages the ratchet-wheel 84 so as to rotate the wheel 84 and therefore, through the wheel 86 and pawl 88, the levers 64, 65 with the shaft 79. Engagement of the abutment 94 with the plate 63 brings the lever 65 to rest but the members 64, 84, 86 continue to rotate until the abutment 92 reaches the plate, the drive to these parts having meantime been disconnected by a cam surface 97 on the lever 65 engaging a pin 96 on the pawl 82. Engagement of the parts 92, 63 brings the members 64, 84, 86 to rest and with them the cams 68 ... 77, the shaft 79 meanwhile continuing its rotation. When the cam 80 causes the plate 63 to move free of the abutments 92, 94, the levers 64, 65 move back into their normal positions relative to the shaft 79 and to each other under the action of the springs 90, 93 but the ratchet-wheels 84, 86 together with the cams remain in their set back position relative to the shaft 79 due to the action of another pawl 99 on the pin 91<SP>1</SP> engaging the wheel 86. The pawl 88 slips over the teeth of wheel 86 during the return to normal of levers 64, 65 and the driving pawl 82 is allowed to re-engage the wheel 84. These operations recur once during each revolution, so as to cause the impression roller to move into contact with the printing cylinder at a later point in each cycle with the result that each sheet receives an imprint of a line which, on the printing-surface, follows the line printed on the preceding sheet. A spring 98 attached at its ends to the member 98a and the sleeve 85 respectively is wound up during the relative movement between the sleeve and the shaft 79. By simultaneously releasing the pawls 88, 89, the spring 98 can be allowed to bring the parts back into their original starting positions. By disconnecting the arm 81 and cam 80, the same line or lines can be printed on all sheets. In a modified arrangement (Fig. 5, not shown), the toggle mechanism operating the impression roller is latched in the inoperative position and subsequently unlatched. In Fig. 6 an arrangement is shown for moving the copy sheet as required, comprising a shaft 138 driven from printing-cylinder shaft 31 carrying two cams 139, 147 in one plane and a third cam 145 in an adjacent plane. Prior to the operation of the impression roller 129 to effect printing of the heading, the cam 139 frictionally engages a roller 140 which through friction rollers 141, 142, 143 rotates the roller 129, so that the latter in cooperation with the spring-pressed roller 135 feeds the copy sheet forward to the printing line in readiness for the .printing of the heading. Subsequent to the heading printing, the cam 145 engages a roller 146 which, through the rollers 140 ... 143 rotates the impression roller 129 in the reverse direction to move the sheet rearwardly into position for moistening the line or lines. Finally, the cam 147 engages the roller 140 and causes the copy sheet to be moved forward into position for the printing of the line or lines. The shaft of the impression roller is braked to prevent jerking when the cams engage the rollers 140, 146. Toothed gearing (Fig. 7, not shown) and ratchet gearing (Fig. 8, not shown) sheet-control means are also described. In the first-mentioned arrangement, springy .wires are pressed against the printing-surface when the moistening device is lifted, i.e. during printing. In further modifications (Figs. 13, 13a and 15, not shown) a single cam controlling the line printing is stepped backwardly relatively to each shaft during each revolution of the printing cylinder as described with reference to Figs. 2, 3. Keyed to the shaft are three other cams, two controlling the moistening and printing of the heading, and the third for effecting printing on one sheet of the whole of the matter on the printing surface; this latter operation is effected by moving the three cams axially of the shaft to bring the third cam into alignment with rollers corresponding to the rollers 66, 67, Figs. 2, 3. In Fig. 14, cams 396, 397 which control the mechanism for effecting the printing of the line and heading respectively, act on a roller 401 forming part of the mechanism ope