Device for determination of operating angle of distributor rollers

Abstract

A control system for optimizing the starting angle of a vibrating roller for production of an evenly distributed film of ink on the printing plate of a printing press, particularly an offset press, in which a reciprocating drive connection is provided between the press drive and the vibrating roller for reciprocation of the latter. A chart is provided for each one of a complete set of reference distribution starting angles for the vibrating roller, each chart showing for each starting angle a corresponding ink density distribution curve which, when matched to the observed ink density distribution in a printed product, provides direct reading of optimum starting angle. A variable phase changer is interposed in the drive connection leading to the vibrating roller for directly setting the starting angle to optimum value. In a preferred embodiment of the invention the charts are arranged angularly spaced on a rotatable carrier disc which is coupled to a first servo device, while the phase changer is coupled to a second servo device, the servo devices being coupled together by servo circuitry for angular coincidence at an angle which is manually set. When the disc is in reference position (for example, zero), the optimum starting angle is read off the chart, following which the disc and phase changer are set, simultaneously, to the optimum angle.