Method and apparatus for printing a web

#The invention concerns a method and an apparatus for printing material in web form.

#In this specification the term print image is used to denote a print image applied to a web of material, which may be a complete print image in itself, or alternatively a partial print image such that a plurality of such partial print images are applied to the web of material at the same location in order thereby to produce an overall print image, as is the case for example with multi-color printing.

#Furthermore in this specification the term printing is intended to include any printing and decorating processes such as relief printing, for example flexographic printing, intaglio printing and rotary screen printing, but also stamping or embossing, in particular hot stamping or embossing, without however that list of possible processes being exhaustive.

#FIG. 1 is a diagrammatic side view of a printing machine having a plurality of printing stations,

#FIG. 2 is a diagrammatic side view of a printing station on an enlarged scale,

#FIGS. 3A through 3C each show a greatly simplified part of the structure shown in FIG. 2 on an even larger scale showing the co-operating components in three positions which occur in succession during a working cycle, and

#Referring firstly to FIG. 1, shown therein is a printing machine 10 for printing on material in web form, as generally indicated at 12, which is drawn off a first roll 14 and passed in a general transportation direction indicated by an arrow 16 through first through fourth printing stations I–IV arranged in succession in the transportation direction 16. The printing stations are each of substantially the same structure. After the complete printing operation has been effected by the web 12 passing through the printing stations the web 12 is then wound on to a second roll 18.

#Each printing station I–IV is provided with a printing mechanism which is generally indicated by reference numeral 20 in the printing station IV, and devices for transporting, positioning and guiding the web 12 to be printed upon, in the region of the respective printing station. The web passes into each respective printing station at a constant intake speed indicated at V1.

#In the embodiment shown in FIG. 1 the printing stations are in the form of cylinder printing mechanisms whereas the printing mechanism shown in FIG. 2 is in the form of a short printing mechanism. Both types of printing mechanism can be employed here and the general structure thereof involves generally known design configurations so that they do not need to be described in greater detail at this juncture.