GB972347A - Improvements in or relating to offset printing machines - Google Patents

Abstract

972,347. Rotary offset printing machines. W. RITZERFELD, and G. RITZERFELD. Oct. 30, 1962 [Nov. 9, 1961], No. 40923/62. Heading B6C. In an automatically operated rotary offset printing machine for effecting selective printing from a master sheet 25, this sheet and successive copy sheets 27 are carried by a rotatable cylinder 1 past swingable and electromagnetically operated offset rollers 7 and 5 the roller drive deriving from the cylinder through gear trains 9, 11, 13 and 9, 10, 12. The machine also comprises an electromagnetically operated offset roller washing device 16, master sheet damping systems 17 and 18, an inking mechanism 19 ... 21 and a suction operated copy sheet feed device 26. The machine is automatically operated through electromechanical apparatus which comprises a suitably arranged contact arm 3 rotatable with the cylinder and having an actuating tip 33, a keyboard 28, a fixed contact bank 4 carrying appropriate contact studs such as 29 ... 31 and contact rings and half-rings 46, 42, 51 and 48, 50, a limit switch 34 operable by the tip 33, relays and electrical circuitry and electromagnets 8, 6 and 38 for actuating the roller 7, the roller 5 and the washing device 16, respectively. In operation keys on the keyboard 28 are actuated to select the particular lines or sections of the master it is required to print on each sheet 27. The machine produces a printed copy sheet every revolution of the cylinder 1, alternate sheets coming from the same offset roller. Each roller receives an image from the master sheet and transfers it to a copy sheet every other revolution of the cylinder the operational movements of roller 5 being as follows-roller 7 has identical movements but, relative to the rotating cylinder, lags by 360 degrees during passage therebeneath of the inked master and dependent upon the keys which have been actuated the roller trips " in " for every desired line or section and then is held off with further rotation prevented by a pawl and ratchet mechanism 52. The copy sheet immediately following the master is printed on by the already prepared roller 7 whilst the roller 5 is automatically rotated in a reverse direction by an electromagnetic clutch arrangement 14 to a position in readiness for its printing operation on the passage of the next copy sheet therebeneath. During this printing operation it is swung into contact with the copy sheet and rotated through one complete revolution. When sufficient copies have been printed the main switch 32 is opened manually and the machine continues to operate until the tip 33 actuates the switch 34 which now de-energizes a relay 35. This simultaneously effects deenergization of the offset roller control apparatus and energization of the electromagnet 38 which swings the washing mechanism 16 against the rollers cleaning the same in readiness for the neck printing operation.