Harris Corporation

Harris-intertype Corporation

Algirdas J Krygeris

John M Manring

James E Murray

An apparatus for remote control of a printing press having a plurality of printing units each having a number of ink fountain key actuators, avoids duplication of remote control circuitry and of wiring by multiplexing a small number of remote controls and control wires. Command data are produced at a remote station, and temporarily stored there. Command data for all of the printing units which are to be controlled are then transmitted as a serial data stream over a pair of wires to storage registers located at the printing press. Thereafter, all of the actuators are energized in accordance with the data stored in their respective registers. A complete serial data stream is transmitted to the press once for each AC cycle of the power line frequency, and the actuators move in accordance with every such transmission of data. After a predetermined time interval, during which the identical serial data stream is repeatedly transmitted, the command data which is stored at the remote control station is replaced by freshly computed data, and the entire cycle is repeated.

Multiplexing of actuator control signals

A method for compensating measurements of optical density of ink printed by a printing press in which amounts of light reflected from a printed test patch area and from an adjacent unprinted reference area are measured. The measurement sensitivity of sensing apparatus for measuring light from the printed test area need not be equal to the measurement sensitivity of sensing apparatus for measuring light from the unprinted reference area because the relative sensitivities of the two sensing apparatuses are ascertained before the press starts printing. The relative sensitivities are ascertained by making preliminary measurements of light from areas known to have equal reflection densities, for example unprinted paper. The results of these preliminary measurements are stored in a memory and employed later automatically to compensate density measurements based on readings made by the two sensing apparatuses while the press is printing.

Automatic compensation for densitometer imbalance

A system for predetermining appropriate settings for the ink flow control devices of a printing press in dependence upon the average inked area in each of a plurality of image zones whose ink supply rate is controlled by a respective one of the ink flow control devices. An image-bearing member such as a lithographic printing plate is imaged onto an electronic camera tube where it is scanned. Electrical signals from the camera tube are integrated for each ink control zone and the resultant signals indicate the appropriate settings for the ink flow control devices, which can be remotely controlled. Spatial variations in illumination are compensated; output signals are automatically normalized.

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Richmond Heights, OH, United States of America

Algirdas J Krygeris