Patent GB-696034-A (GB)
Title: An improved method of line printing device for duplicating a selected line or lines of a master sheet
IPC: B41L11/00
Filed: 1950-05-12
Abstract: 696,034. Copying documents; printing-surfaces. DITTO, Inc. May 12, 1950 [May 18, 1949], No. 11939/30. Class 100(ii) A method of duplicating selected lines of a master sheet in consecutive order on a series of copy sheets, which involves the use of first and second block-out strips shiftably mounted on the surface of a drum, comprises the steps of disposing the master sheet on the drum with the lines perpendicular to the axis of the drum, disposing the block-out strips on the drum in spaced relationship to expose a selected line and block out those portions of the master sheet above and below that line, feeding copy sheets from a stack into cooperative engagement with the drum and master sheet to duplicate that line, shifting the first blockout strip into edge to edge engagement with the second strip to cover the selected line previously duplicated and shifting the second block-out strip to expose a new line. The master sheet may be separated into a heading master and line master, the heading master being disposed over the first block-out strip so that the heading and a selected line from the line master are duplicated. A duplicating machine for carrying out the method comprises a frame 28a, duplicating drum 29 and feed table 30 on which are mounted a sheet feeding tray 31 and advancing mechanism 32. A master sheet is divided into a heading master 23 and line master 24, the line master 24 being held on the drum 29 with its lines running circumferentially by means of grippers 35 operated by a control lever 34 which is also used to control the operation of the drum which is motor driven. The construction of the grippers is described in Specification 472,869. Forwardly of the grippers, a slot 39 is provided in the drum wall, with a web 40 separating the slot from the interior of the drum to hold a block-out strip 41 and a combined block-out strip and master carrier 42, each of which comprises a piece of flexible material 48, such as very thin gauge sheet steel or tracing cloth, secured to a U-shaped steel clip 47 which fits into the slot 39 and the strip 42 further comprises a flap 49, integral with by turning over or secured as by spot welding to the material 48 to form a pocket 51 to receive the heading master 23. The steel clips 47 are shiftably held in the slot 39 by a number of pole pieces 46 of magnetic material extending up to or just below the upper surface of the web 40 and secured to the poles of a number of bar magnets 44 mounted on a cross bar 43 in the drum 29 by means of brackets 45, the bar and brackets being of non-magnetic material. The tray 31 comprises a pair of L-shaped side guides 90, 91 mounted for sliding movement in transverse slots 92, 93 respectively in the table 30 by means of spaced screws on which nuts 95 can be tightened to secure the guides in any desired position relative to the drum 29 and to each other and, so as to allow sliding movement together, a tie bar 100 may be provided to maintain their relative spacing and which is secured thereto by nuts on screws 98 sliding in a further slot 97 in the table 30. The tray 31 is positioned relative to the drum 29 by means of a spring loaded detent in a cylinder 101 secured to guide 90 which engages one of a number of recesses 103 in the table 30 or in a bar 115 overlying the table. Corresponding indicia 104, 105 are marked on the table 30 and the drum 29. Rubber pads may be provided in the side guides to engage the sides of a stack 80 of copy sheets. The sheet advancing means 32, which is comprised in housing 71 rotatably mounted on' a shaft 66, is mounted on the feed tray 31 so as to move therewith by means of yokes 108, 109 which embrace the shaft 66 either side of the housing 71, the yokes being either integral with or, as shown in Fig. 16, adjustably mounted in slots 112 in, brackets 106, 107 secured to the side guides 90, 91 towards the front of the tray. The advancing means comprises rubber wheels 79 pinned to a shaft 77 journaled in the housing 71 so that the wheels 79 rest on the stack 80 of copy sheets in the tray 31, the shaft 77 being driven from shaft 66 by gears 76, 78 and chain 81 located inside the housing 71. Intermittent unidirectional rotation of shaft 66, synchronized with the rotation of drum 29, is obtained by means of a gear sector 60 pivotally mounted in frame 28 to reciprocate through any suitable mechanism; the sector 60 driving a pinion 61 mounted on one element of a free wheeling clutch 62, the other element of clutch 62 being mounted on a stub shaft 63 journaled in the frame. The stub shaft 63 drives the shaft 66 through a sleeve 64 removably connected to shaft 63 by a pin 65 through end slots, and connected to the shaft 66 by a pin 69 in a slot 68 which permits relative movement to allow removal of the other end of shaft 66 from its socket 67 in which it is normally maintained by a coil spring 70. The housing 71 is mounted by means of bushings 75 on a sleeve 73 slidable on shaft 66 to which it is keyed by a dog point screw 74 in a keyway 72. The screw 74 is threaded into the hub portion of gear 76 so that it rotates with the shaft 66 causing the wheels 79 to be rotated to advance a copy sheet from the stack as the drum 29 is rotated. The housing 71 may be swung upwardly to replenish the stack 80 and rests on the stack by its own weight. The tray 31, together with the sheet advancing means 32, is shifted a corresponding distance each time that the block-out strips are shifted so that the heading and selected line are duplicated from the masters 23, 24 in the same position on the copy sheets. Specification 543,728 also is referred to.