GB753994A - Improvements in and relating to printing apparatus - Google Patents

Abstract

753,994. Printing-machines. ACCOUNTTOKENS, Ltd. Feb. 1, 1955 [Feb. 19, 1954] No. 5029/54. Class 100 (2). In a printing-machine of the kind comprising a base 1, Fig. 1, to support a relief plate 4, and a printing head 5 mounted for pivotal movement towards the base and carrying a roller 13 adapted to co-operate with the relief plate to print on a sheet overlying the relief plate, the roller is mounted on a carriage 12 (see also Fig. 3) movable transversely across the width of the head 5 under the action of a spring, there being provided means whereby the spring is automatically loaded as the printing head is moved into printing position and means for releasing the carriage when the printing head is in this position. The roller 13 may be inkimpregnated or it may act through an inkribbon. A bell-crank lever 15 pivoted to the upper wall 8 of the head 5 has a forked end for engagement with a pin 16 on the carriage and the other arm 17 is connected to a spring 18. A hooked latch 19, connected to a fixed pivot point 20 spaced from the hinge axis 6 of the head, has a slot for engagement with arm 17 so that as the head is moved downwardly towards the base the latch pulls the lever 15 in a clockwise direction, thereby moving the carriage across the head and loading the spring 18. The latch is urged into engagement with arm 17 by a leaf-spring 21 and may be displaced out of engagement by pressure on a button 25 acting through an arm 26. A latch 23 may be provided to hold the head 5 in the operative position. In operation the sheet to be printed is placed over the relief plate 4 and the head 5 closed down so as to load the spring. The button is then pressed to release the carriage which moves the roller over the paper, inking those parts which are supported by the relief plate. At the end of the primary stroke of roller 13 a projection 27 on the carriage 12 is adapted to strike and release the latch and allow the head to rise under spring action. In a modification mechanism is provided to release the latch 19 automatically as soon as the head has arrived in the operative position. The bellcrank lever mechanism may be replaced by a cable connected at one end to the carriage and at the other to a spring-actuated drum.