Abstract: An improvement in the measuring elements of closed circuit systems for controlling-correcting printing in offset printing machines is provided. The values of measurements are amplified, analogically commutated, converted from analog to digital form, and then microprocessed so as to be compared with standard values established in a memory program provided for each one of the valves controlling the printers block of each one of the printing bodies. A reading is taken decomposed into three variables, each one of which corresponds to one of the three basic colors of the visible spectrum in which the light from the colored stain is diffracted by means of a ROWLAND diffraction grating in which there is reflected the light from optical fibers arranged at 45.degree. angles with respect to the printing paper, and which direct a beam of light on the colored stain.

Abstract: A method is disclosed for accelerating the drying of offset inks. An additive composition comprising (a) 15 to 85 percent of functional amino polydimethylsiloxane and (b) 85 to 15 percent of a mixture of ethylene oxide and propylene oxide, wherein the ethylene oxide is present in an amount of from 15 to 85 percent with respect to the propylene oxide, is added to an offset printing ink.

Abstract: A sheet turning machine includes two slidable platforms, one of which is ascending while the other is descending, the upward travel of one of the platforms being synchronized with the downward travel of the other platform. The ascending platform is arranged between two vertical guide columns solidly fastened to a fixed chassis, while the descending platform is guided between two columns solidly fastened to a frame which tilts about the fixed chassis. The ascending platform is arranged under the field of action of a suction pump. A turning bridge is arranged above the descending platform and includes an endless conveyor belt which has a lower or return run part which diverges in a direction perpendicular to the columns guiding the descending platform. At the front of a roller whereat the endless belt returns, there is an air generator capable of maintaining a sheet of paper fixed to the belt while the sheet, travelling with the belt, passes from the upper run to the lower or return run.