GB850621A - Improvements in or relating to rotary duplicating machines - Google Patents

Abstract

850,621. Copying documents. RITZERFELD, W., and RITZERFELD, G. March 31, 1958 [April 18, 1957], No. 10227/58 Class 100(2) A rotary duplicating machine for printing lines on sections of a text, which lie more than one line space apart on a master sheet, on to a copy sheet in closer succession, comprises a rotatable printing element carrying the master sheet, and a counterpressure element movable into and out of cooperating position therewith by an electromagnet controlled by a switching contact on a member rotatable in timed relation with the printing element, the contact being operable on rotation of said member by a plurality of switching means which do not revolve with the member, are allocated to individual lines or sections of the master sheet, and are movable in the direction of the axis of rotation of said member into the path of rotation of the switching contact by a corresponding plurality of setting means. The printing drum 1, Fig. 1, rotates a shaft 59, Figs. 1 and 2, to which is secured a flange 57 carrying a contact switch 55. A contact switch 56 is carried by a second flange 58 rotatable on the shaft and carried round by the flange 57 by means of a ratchet wheel 64 on the flange 58 and a locking pawl 62 on the flange 57. At the end of each revolution, if a roller 69 is in operative position, it engages a switching pawl 63 to release the pawl 62, whereupon the flange 58 is rotated by a torsion spring 70 oppositely to the rotation of the shaft 59, through a distance corresponding to one line, whereafter the pawl 63 runs off the roller 69 and the pawl 62 engages the ratchet wheel 70. A stationary disc 52 accommodates a series of keys 51 each corresponding to a line and carrying switching rollers 51a, which can be moved into the path of the contact 55 by fully depressing the keys and into the path of both contacts 55, 56 or only the contact 56 by partially depressing the keys. Ball and spring detents hold the keys in any position. Closing of contacts 55, 56 by contact with a switching roller makes contact between slip rings 65, 66 and 67, 68 respectively. The ring pairs are each contacted by a pair of brushes completing circuit from a rectifier supplied by a transformer to the magnets 28 controlling the counterpressure roller 10, which is thereby moved against the drum 1 whenever either contact 55 or 56 is closed. There is also a manual switch in each of the circuits of contacts 55, 56, whereby either can be immobilised. Contact 55 and full key depression is used for printing part of the text (e.g. heading) repeatedly, while contact 56 and partial depression is used for printing lines progressively.