Method of automatic register setting of printings in a rotary machine and device for working the method
First Claim
1. A method for an automatic register setting of printings printed by plate cylinders in a rotary machine using inks of a plurality of colors, wherein the rotary machine comprises a succession of printing units respectively positioned downstream with respect to the travelling direction of a web to be printed, at least one pulse generator, two pull rollers located downstream of the printing units, compensating rollers used with the plate cylinders to correct register errors determined by means of register marks printed on the web when pressing cylinders are lowered against the plate cylinders, scanning heads each located near and downstream of the respective printing units, each printing unit includes one of the plate cylinders and one of the pressing cylinders which are controlled by one of a plurality of control devices, the method comprising the steps of:
- a) lowering the last pressing cylinder;
b) aligning the scanning head of the printing unit so that it is positioned vertically to the successive pass of the register marks printed by the plate cylinder;
c) phasing the printing unit such that a scanning gate is placed around the register mark;
d) repeating the successive steps a), b) and c) for all the printing units, successively upstream, excluding the first printing unit located most upstream;
e) raising all of the pressing cylinders which have been previously lowered, and lowering the first pressing cylinder as soon as all the pressing cylinders raise up;
f) determining the register error in a mode called “
mark-to-cylinder”
;
g) correcting, at a constant tension of the web, the register error by a compensating roller or a plate cylinder;
h) determining a residual register error in a mode called “
mark-to-mark”
;
i) correcting the residual register error with a compensating roller or a plate cylinder; and
j) repeating the successive stages f), g), h), i) for all the printing units, successively downstream, starting from the second printing unit.
1 Assignment
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Accused Products
Abstract
Device and method for the automatic register setting of printings printed by plate cylinders in a rotary machine using inks of a plurality of colors. The printing machine particularly comprises a succession of printing units, at least one pulse generator, two pull rollers located downstream of the printing units, a combination of plate cylinders and compensating rollers to correct some register errors, scanning heads each located near and downstream to the respective printing units. Each printing unit particularly includes one of the plate cylinders as well as one of the pressing cylinders. Each pressing cylinder is controlled by a control unit.
47 Citations
11 Claims
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1. A method for an automatic register setting of printings printed by plate cylinders in a rotary machine using inks of a plurality of colors, wherein the rotary machine comprises a succession of printing units respectively positioned downstream with respect to the travelling direction of a web to be printed, at least one pulse generator, two pull rollers located downstream of the printing units, compensating rollers used with the plate cylinders to correct register errors determined by means of register marks printed on the web when pressing cylinders are lowered against the plate cylinders, scanning heads each located near and downstream of the respective printing units, each printing unit includes one of the plate cylinders and one of the pressing cylinders which are controlled by one of a plurality of control devices, the method comprising the steps of:
-
a) lowering the last pressing cylinder;
b) aligning the scanning head of the printing unit so that it is positioned vertically to the successive pass of the register marks printed by the plate cylinder;
c) phasing the printing unit such that a scanning gate is placed around the register mark;
d) repeating the successive steps a), b) and c) for all the printing units, successively upstream, excluding the first printing unit located most upstream;
e) raising all of the pressing cylinders which have been previously lowered, and lowering the first pressing cylinder as soon as all the pressing cylinders raise up;
f) determining the register error in a mode called “
mark-to-cylinder”
;
g) correcting, at a constant tension of the web, the register error by a compensating roller or a plate cylinder;
h) determining a residual register error in a mode called “
mark-to-mark”
;
i) correcting the residual register error with a compensating roller or a plate cylinder; and
j) repeating the successive stages f), g), h), i) for all the printing units, successively downstream, starting from the second printing unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device for providing an automatic register setting of printings printed by plate cylinders, the device comprising:
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a rotary machine using inks of a plurality of colors, the rotary machine comprising a succession of printing units respectively positioned downstream with respect to the traveling direction of a web to be printed;
at least one pulse generator;
two pull rollers located downstream of the printing units;
pressing cylinders that are lowered against the plate cylinders to determine register errors by means of register marks printed on the web;
compensating rollers cooperating with the plate cylinders to correct the register errors;
scanning heads, each of the scanning heads located near and downstream to the respective printing units, wherein each printing unit includes one of the plate cylinders and one of the pressing cylinders which are controlled by one of a plurality of control devices, wherein the device performs the functions of;
a) lowering the last pressing cylinder;
b) aligning the scanning head of the printing unit so that it is positioned vertically to the successive pass of the register marks printed by the plate cylinder;
c) phasing the printing unit such that a scanning gate is placed around the register mark;
d) repeating the successive steps a), b) and c) for all the printing units, successively upstream, excluding the first printing unit located most upstream;
e) raising all of the pressing cylinders which have been previously lowered, and lowering the first pressing cylinder as soon as all the pressing cylinders raise up;
f) determining the register error in a mode called “
mark-to-cylinder”
;
g) correcting, at a constant tension of the web, the register error by a compensating roller or a plate cylinder;
h) determining a residual register error in a mode called “
mark-to-mark”
;
i) correcting the residual register error by a compensating roller or a plate cylinder; and
j) repeating the successive stages f), g), h), i) for all the printing units, successively downstream, starting from the second printing unit, and wherein the control devices of the pressing cylinders are controlled by an automatic control circuit connected to a calculation circuit of a register error. - View Dependent Claims (10, 11)
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Specification