Flexographic printing machine with a multiplicity of individually driven printing units
AssigneeLemo Maschinenbau GmbH
InventorWERNER THEUNER
Life of this patent
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Abstract
A flexographic printing machine for extensible webs like synthetic resin foil webs has a tension-measuring or length-measuring arrangement along the path through the multiplicity of printing units so as to control a web-drawing device at the downstream side of the path to ensure registry of the imprints or impressions produced by the printing units.
Claims9
A flexographic printing machine for printing a succession of imprints upon an extensible web of a material, said printing machine comprising:
- a housing;
- means for supplying said extensible web to a printing path in said housing;
- a multiplicity of individually driven printing units arrayed along said path and traversed in succession by said extensible web;
- a web-drawing unit along said path downstream of a last of said printing units and traversed by said web;
- measuring means along said path responsive to a property of said material during the passage of said web along said path representing elongation along said path;
- and
- a computer-controlled evaluation and regulating device operatively connected to said measuring means for controlling said web drawing unit in response to a degree of elongation of said web to maintain positioning of imprints by the printing units along said path.
A method of printing an extensible web of a material which comprises the steps of:
- (a) passing said web along a printing path through a multiplicity of individually driven printing units of a flexographic printing machine arrayed along said path;
- (b) measuring a property of said web representing a degree of elongation of said web along said path;
- and
- (c) controlling a web-drawing unit engaging said web downstream of a last of said printing units along said path and driven by a computer control in response to the measured property to maintain positioning of imprints by the printing units along said path.
A method of operating a flexographic printing machine for the flexographic printing of an extensible web in the form of a synthetic resin foil and in which the web is passed along a printing path through a succession of individually driven printing units, the improvement which comprises the steps of:
- (a) measuring a property of said web selected from changes in the length of web tension during passage of said web along said path;
- and
- (b) controlling withdrawal of said web from said path in response to said property by comparison of a measured value with a predetermined setpoint for comparison between measured values at inlet and outlet portions of said path to maintain elongation of said path substantially constant.
Dependencies are inferred from the claim text.