FI103876B - Method of use in flexo printing machine - Google Patents

Description

, 103876

A method for use with a flexo printing press

TECHNICAL FIELD The present invention relates to a method for use with a flexo printing machine, the printing apparatus of which comprises a first and a second roller 5, the axes of which are substantially horizontal and between which the material to be printed is arranged to pass.

Often, a flexo-printed product after printing is coated with, for example, a PE film. Thus, by means of a flexo printing press, the material web is to be led, as a separate operation, to a separate coating machine, in which the overlay is performed. Thus, the coating requires both time and separate equipment investment in the coating machine.

Summary of the Invention

It is an object of the present invention to provide a method for use in connection with a flexo printing machine, which method can be used to dispense with coating a web of material printed with a flexo-15 printing machine on a separate coating machine or line. This is achieved by a method according to the invention, characterized in that it comprises the steps of setting a predetermined gap between the first and second rolls, rotating the first and second rolls at a predetermined circumferential velocity of the material web; and a coating material is fed to the nip between the second roll and the material web for one-sided coating of the material web.

According to a first embodiment of the invention, the first roll is a drawing roll of a flexo printing press and the second roll is a rubber roll thereof.

; According to a second embodiment of the invention, the first roll is a rubber roll of a flexo printing press and the second roll is a raster roll thereof.

When applying the method according to the invention, the flexo-30 printing machine is thus advantageously obtained as a multifunctional machine, which can also be used to coat a machine-printed material web. The Flexo printing machine can then be used for some purposes, for example, to produce layered products replacing PE films by applying the process of the invention.

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List of figures

In the following, the method of the invention will be described in more detail with reference to the accompanying drawing, the figure of which schematically shows the part of a flexo printing machine in which the method of the invention is applied.

Detailed Description of the Invention

The figure of the accompanying drawing schematically shows the part of a flexo printing machine in connection with which the method according to the invention is to be applied. This part of the printing press comprises essentially horizontal rolls, a draw roll 1 and a rubber roll 2 arranged conventionally rotatable therebetween, between which a pressable web 3 is guided. The printing press further comprises a raster roll 7 which is arranged to rotate against the rubber roll 2.

In a conventional flexo printing press, the rubber roller is not driven, i.e. it is not rotated by a motor, but only the drive roller 1 comprises such a steplessly variable speed drive. When applying the method according to the invention, the rubber roller 2 or the rubber roller 2 and the raster roller 7 may also be provided with such a drive which enables infinitely variable speed control. Unlike a conventional flexo printing press, the nip between the draw roll 1 and the rubber roll 2 is also slightly opened so that they have the clearance 5 required by the coating process according to the invention. As shown, the web 3 to be coated is guided along the draw roll 1. wherein said clearance 5 is practically located between the material web 3 and the rubber roll 2. If the raster roll 7 is also provided with drive: the material track 3 can alternatively be guided through the 25 nip 8 between the rubber roll 2 and the raster roll 7, along the rubber roll 2.

In the embodiment of the invention in which the web 3 is guided through the nip of the pull roll 1 and the rubber roll 2, the coating material is conducted to the nip 6 between the web 3 and the rubber roll 2 when the coating is carried out. by gravity in the nip 6, because the nip 6 is located between the rubber roller and the web 3 in a cushion above the rubber roller axis. During the coating process, both the pull roller 1 and the rubber roller 2 are rotated such that their direction between these rollers is opposite to the direction of the web 3 transfer. Thus, the coating can be thought of as a kind of 35 "countercurrent coating". For optimal operation and tensile 3 103876

The peripheral speeds of Ian 1 and the rubber roller 2 are set at a predetermined ratio with the speed of the material web 3. This rate is determined by the properties of the coating, such as viscosity, on the one hand, and the properties of the substrate to be coated, on the other. By the method according to the invention, the material web 3 can be coated on its surface facing the rubber roll 2.

In the embodiment of the invention in which the web to be coated is guided between the rubber roll 2 and the raster roll 7, the coating material is introduced into the nip 8 between the web and raster roll 7. Otherwise, the coating procedure is exactly the same as described above between the rubber roller 2.

The material web suitable for coating in the process of the invention may be, for example, a fiber-based web having a surface weight of 40 to 370 grams per square meter and a thickness of 40 to 350 micrometers. Exemplary preferred coated substrates include cardboard, preferably sat-pocket cardboard, or paper such as preferably greaseproof paper. The substrate may also be a plastic film or laminate.

The coating agents or coatings used in the process of the invention may be in the form of an aqueous or solvent dispersion and may contain various coating agents such as barrier materials, binders, dispersion lacquers, may be pigmented or non-pigmented, and thus may contain or pigments.

The above process of the invention has been described by way of one exemplary embodiment only, and it is to be understood that it may also be applied to some extent, without departing from the scope defined in the appended claims.

Claims (3)

A method of use in connection with a flexo printing machine, the color apparatus comprising a first (1; 2) and a second roller (2; 7), the shafts of which are substantially horizontal and between which a web of material to be printed is arranged to run; characterized by the method comprising steps in which a predetermined size game (5) is installed between the first (1; 2) and the second (2; 7) valleys, the first (1; 2) and the second (2; 7) the roller is rotated in the opposite direction to the direction of travel of the material web (3) with predetermined peripheral speeds relative to the material web (3) and coating means (4) measured in the nip (6; 8) between the second roller (2). 7) and the material web (3) for coating one side of the material web (3). 15 Method according to claim 1, characterized in that the first roller is the flex roller (1) of the flexo printing machine and the second roller is its rubber roller (2). Method according to claim 1, characterized in that the first roller is the rubber roller (2) of the flexo printing machine and the second roller is its raster roller (7).