US 4,553,478 AGranted

Printing machine pre-setting arrangement

AssigneeMAN Roland Druckmaschinen AG

InventorsHarry M. Greiner, Hermann Fischer, Claus Simeth

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Abstract

A system for presetting register and color zone adjusting devices in a multi-color rotary printing machine uses digitally-driven optical scanners axially traversing the plate cylinders under control of at least one numerical computer. Machine-specific characteristics are programmed in non-volatile memory as referenced values. Data processing is not required to be conducted external to the printing machine. The system is compact and requires practically no re-adjustment or entry of desired values from the machine operator. The machine operator, however, may enter coordinates for printing areas on the printing plate in order to speed up the scanning process for determining the initial color zone preset. The scanner multi-functionally scans the printing plate for both register adjustment and for integrating the ratio of printing to non-printing area for each inking zone. The system is easily reprogrammed and the optical scanner is interchangeable with a densitometer in order to provide alternative control functions during printing, such as the regulation of inking and dampening.

Claims14

Dependent claims

In a rotary printing machine having a printing plate mounted on a plate cylinder, a machine frame to which the plate cylinder is journaled, a drive for rotating the plate cylinder, automatic means for adjusting the axial and circumferential register of the plate cylinder, and automatic means for dosing a desired amount of ink to a plurality of axially-displaced inking zones on the printing plate, an apparatus for presetting the axial and circumferential register and the means for zonally dosing ink comprising, in combination,

means for sensing the angular position of the plate cylinder drive,
an optical scanner and traversing mechanism mounted to the machine frame for axial scanning of the printing plate including means for driving the optical scanner to a commanded axial position, and
a numerical computer including memory, being responsive to the angular position of the plate cylinder drive, the axial position of the optical scanner, and a signal from the optical scanner, and having means to selectively operate the machine drive, move the optical scanner to commanded axial positions, and generate control signals for said means for adjusting axial and circumferential register and said means for dosing ink, said numerical computer further comprising
(a) means for sensing the axial and circumferential positions with respect to the machine frame and machine drive, respectively, of at least one register mark engraved on the printing plate,
(b) means for adjusting the axial and circumferential positions of the register mark so that the register mark is aligned with predetermined axial and circumferential positions, and
(c) means for scanning printing areas on the printing plate and determining ink dosing control signals responsive to the ratio of printing to non-printing area in the respective inking zones on the printing plate,
so that a single optical scanner multi-functionally scans the printing plate to preset the register and zonal ink dosing within the printing machine under control of the numerical computer.

4 more elements

A method of operating a numerical computer having a memory for the presetting of a rotary printing machine having a printing plate mounted on a plate cylinder, a machine frame to which the plate cylinder is journaled, a drive for rotating the plate cylinder, automatic means for adjusting the axial and circumferential register of the plate cylinder, automatic means for dosing a desired amount of ink to a plurality of axially displaced inking zones on the printing plate, means for sensing the angular position of the plate cylinder drive, and an optical scanner and traversing mechanism mounted to the machine frame for axial scanning of the printing plate including means for driving the optical scanner to a commanded axial position,

said computer being responsive to the angular position of the plate cylinder drive, the axial position of the optical scanner, and a signal from the optical scanner, and having means to selectively operate the machine drive, move the optical scanner to commanded axial positions, and generate control signals for said means for adjusting axial and circumferential register and means for dosing ink,
said method comprising the steps of:
(a) moving the optical scanner to the predetermined location of at least one register mark engraved on said printing plate, and thereupon correlating a signal from said optical scanner with the angular position of the plate cylinder drive and the axial position of the optical scanner to determine the axial and circumferential positions of said register mark engraved on said printing plate,
(b) generating control signals for said means for adjusting axial and circumferential register in response to the determined axial and circumferential positions of said register mark so that the register mark is aligned with predetermined axial and circumferential positions, and
(c) moving said optical scanner to the locations of printing areas on the printing plate and at said locations moving said optical scanner and operating said machine drive to scan the printing areas, and processing said signal from said optical scanner to determine ink dosing control signals responsive to the ratio of printing to non-printing area in respective inking zones on the printing plate,
so that a single optical scanner multi-functionally scans the printing plate to preset the register and zonal ink dosing within the printing machine under control of the numerical computer.

3 more elements

Dependencies are inferred from the claim text.