ES294284A1 - Offset machines - Google Patents

Abstract

An offset machine, Fig. 4, suitable for printing on planar or curved articles comprises a framework including two side walls, an offset cylinder carrying a two-part blanket 1, a plurality of printing cylinders A, B, C, D in contact with said offset cylinder, a plurality of forme inking rollers a, b, c, d, and an inking train including sliding rollers al, a3 and distributing rollers a2, a4 associated with each forme inking roller, screws, Fig. 2 (not shown), for adjusting the printing cylinder A, for instance, against spring pressure being located in a plane at right-angles to a plane containing screws, Fig. 3 (not shown), for adjusting the associated forme inking roller a against spring pressure. The cylinders such as A are mounted in bearings slidably located in guides, machined in the said side walls. Each printing cylinder is adjusted peripherally by means of pinions, Fig. 5 (not shown), and the bearings are then locked to the side walls by screws. The printing cylinders may be axially displaced by screw members adapted to engage the shafts of the cylinders. The cylinder A may be removed without affecting the adjustment of the inking rollers. Inking.-The forme inking roller a, Fig. 3 (not shown), is supported in bearings which are slidable in guides in the side walls. The roller may be removed upon removing plate members. Offset surfaces.-The offset surface, Fig. 1 (not shown), comprises two plastic hemicylindrical members lined with an adjustable amount of polyurethane. The ends of the offset cylinder are threaded so that collars and threaded rings co-operate with the tapered edges of the members to secure them to the cylinder. Printing on curved surfaces.-Articles to be printed are mounted on mandrels 36a-36d, Fig. 6, supported on a rotatable disc 35, Fig. 6. The mandrels are carried by pins 38 which rotate in lever arms 39 rockable about an axis 40 of a socket 401 carried by a bar 41. Screws 42 are provided to adjust the articles with respect to the offset blanket. The bars 41 are radially adjustable to accommodate articles of different diameter. Bottles &c. are printed by removing the disc 35 and connecting the drive to a pair of sprocket wheels, Fig. 8 (not shown), carrying a pair of chains. Each bottle is placed on supports by a pneumatically driven member and engages a socket. The bottles are filled with compressed air before printing. If the bottles are conical the chains are arranged at different levels by rollers, Fig. 7 (not shown). Planar articles to be printed are fed on to the chains which move at the peripheral blanket speed. The machine is adapted to print in four colours.