Machine for generating optically variable image elements

Patent metadata

Field	Value
Publication number	US-11858253-B2
Application number	US-202118025495-A
Country	US
Kind code	B2
Filing date	Aug 18, 2021
Priority date	Oct 1, 2020
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

In some examples, a machine for generating optically variable image elements on a substrate includes a printing substrate infeed and a printing unit including a printing mechanism by which a substrate guided on a transport path is printed with a coating agent containing magnetic or magnetizable particles. A device for aligning the magnetic or magnetizable particles includes a first alignment device in the transport path and a further alignment device arranged upstream therefrom. During normal operation, the further alignment device is fixed to a frame at the transport path. The further alignment device includes a plurality of magnets that are spaced apart from one another transversely to the transport direction and, during operation, remain stationary. The number of magnets included in the further alignment device correspond to a number of columns of image-producing print motifs or groups of image-producing print motifs around a circumference of a forme cylinder.

First claim

The invention claimed is:

1. A machine ( 01 ) for generating optically variable image elements ( 03 ) on a substrate ( 02 ) having a web-format or sheet-format, the machine ( 01 ) comprising:
a printing substrate infeed ( 13 ),
at least one printing unit ( 04 ) comprising at least one printing mechanism ( 11 ; 12 ), by which the substrate ( 02 ) guided on a transport path of the substrate ( 02 ) through the machine ( 01 ) is printed and/or can be printed at least on a first side with a coating agent ( 06 ) containing particles (P) that are magnetic or magnetizable,
a product receiving system ( 27 ) used to receive the substrate ( 02 ) treated in the machine ( 01 ), and
a device ( 07 ) for aligning the particles (P) contained in the coating agent ( 06 ) which is printed at least on the first side of the substrate ( 02 ), wherein the device ( 07 ) is provided in the transport path of the substrate ( 02 ) between the at least one printing unit ( 04 ) and the product receiving system ( 27 );
the at least one printing mechanism ( 11 ; 12 ) comprising, as an image-producing cylinder, a forme cylinder ( 14 ; 16 ) including a plurality of image-producing print motifs or groups of image-producing print motifs around a circumference of the forme cylinder ( 14 ; 16 ), which on a circumferential length corresponding to a print image length are arranged in multiple columns, which are equidistantly spaced apart from one another transversely to a transport direction (T), and on a cylinder width corresponding to a print image width are arranged in multiple rows, which are equidistantly spaced apart from one another in the transport direction (T);
the device ( 07 ) for aligning the particles (P) comprising a first alignment device ( 33 ; 33 ′), which is arranged in the transport path of the substrate ( 02 ) and, in a region of a side of the first alignment device ( 33 ; 33 ′) facing the transport path, comprises a first plurality of magnets ( 44 ) to align, in a surface area comprising the coating agent ( 06 ), at least some of the particles (P) contained in the coating agent ( 06 ) in order to generate image information; wherein:
the first plurality of magnets ( 44 ) of the first alignment device ( 33 ; 33 ′) serving alignment purposes and the substrate ( 02 ) to which the coating agent ( 06 ) containing the particles (P) is applied are movable synchronously with respect to one another, at least on a section of the transport path of the substrate ( 02 ),
the device ( 07 ) for aligning the particles (P) comprises at least one first further alignment device ( 42 ), which is arranged upstream from the first alignment device ( 33 ; 33 ′) in the transport path of the substrate ( 02 ) and which, during operation, is fixed to a frame at the transport path of the substrate ( 02 ) and, transversely to the transport direction (T), the at least one first further alignment device ( 42 ) comprises a second plurality of magnets ( 46 ) that are spaced apart from one another transversely to the transport direction (T) and, during operation, remain stationary in the at least one first further alignment device ( 42 ),
a number of the second plurality of magnets ( 46 ) corresponds to a number of the columns of the image-producing print motifs or groups of image-producing print motifs disposed around the circumference of the forme cylinder ( 14 ; 16 ), and
the second plurality of magnets ( 46 ) included in the at least one first further alignment device ( 42 ) are arranged in the transport path of the substrate ( 02 ) so that the image-producing print motifs or groups of image-producing print motifs are each at least partially aligned with a lateral position of at least one of the magnets ( 46 ) of the second plurality of magnets ( 46 ) of the first further alignment device ( 42 ) along the transport path of the substrate ( 02 ),
wherein the second plurality of magnets ( 46 ) are positioned to perform a pre-orientation of a plurality of the particles (P) included in the coating agent ( 06 ) as the substrate ( 02 ) printed with the coating agent ( 06 ) traverses the at least one first further alignment device ( 42 ), and
wherein the first plurality of magnets ( 44 ) of the first alignment device ( 33 ; 33 ′) are positioned to perform additional orientation of the particles (P) in the coating agent ( 06 ) printed on the substrate ( 02 ) following the pre-orientation of the plurality of particles (P) at the at least one first further alignment device ( 42 ).

2. The machine according to claim 1 , characterized in that the first alignment device ( 33 ; 33 ′) is formed by a magnetic cylinder ( 33 ; 33 ′), which is arranged in the transport path of the substrate ( 02 ) and, in a region of an outer circumference of the magnetic cylinder ( 33 ; 33 ′), comprises the first plurality of magnets ( 44 ).

3. The machine according to claim 1 , characterized in that a drying and/or curing device ( 41 ) is arranged at the transport path of the substrate ( 02 ) so as to act on a point of the transport path of the substrate ( 02 ) located in a magnetically active region of the first alignment device ( 33 ; 33 ′).

4. The machine according to claim 3 , characterized in that the first alignment device ( 33 ; 33 ′) is formed by a magnetic cylinder ( 33 ; 33 ), and the drying and/or curing device ( 41 ) is directed at a circumferential section of the magnetic cylinder ( 33 ; 33 ′) located in the transport path of the substrate ( 02 ), and/or the drying and/or curing device ( 41 ) is implemented as a UV radiation dryer and/or as an LED dryer.

5. The machine according to claim 1 , characterized in that the first further alignment device ( 42 ) serving pre-orientation purposes is arranged upstream from the first alignment device ( 33 ; 33 ′) in the transport path of the substrate ( 02 ) in such a way that arrangement and alignment of the second plurality of magnets ( 46 ) in relation to the surface area comprising the coating agent ( 06 ), and that encompasses the image information to be generated, induces or can induce a homogeneous pre-orientation of a majority of the particles (P), and
the particles (P) have a non-spherical, flat shape, having a longitudinal axis extending for a length in a direction of a longest extension, an axis extending perpendicularly to the longitudinal axis in a direction of a width, and a thickness extending with respect to both axes and being smaller compared to the length and the width, at least with respect to a parallel progression of the longitudinal axis of the particles (P) and which is projected in a plane of the substrate ( 02 ).

6. The machine according to claim 5 , characterized in that the second plurality of magnets ( 46 ) of the first further alignment device ( 42 ) that is arranged upstream from the first alignment device ( 33 ; 33 ′) are configured and oriented in such a way that, in a respective surface area encompassing image information to be generated, the particles (P) are biaxially aligned parallel to one another, both with respect to the longitudinal axis and the axis extending perpendicularly thereto, so that a homogeneous optical impression arises across the surface areas that encompass the image information to be generated.

7. The machine according to claim 5 , characterized in that the second plurality of magnets ( 46 ) of the first further alignment device ( 42 ) that is arranged upstream from the first alignment device ( 33 ; 33 ′) rest against respective stop means ( 59 ), as viewed in a direction perpendicular to the transport path of the substrate ( 02 ), and/or are acted upon by one or more spring elements ( 62 ) with a force pointing in a direction of the transport path of the substrate ( 02 ), and/or that the second plurality of magnets ( 46 ) of the first furthe

Assignees

• Koenig & Bauer Ag

Inventors

• Kreps Edwin
• Thony Emmanuel

Classifications

• B41F19/005 Primary

  with means for applying metallic, conductive or chargeable material · CPC title

• B41F13/0024

  Frames · CPC title

• B41F13/193

  Transfer cylinders; Offset cylinders {(attaching blankets B41F30/04)} · CPC title

• B41F23/0409

  Ultraviolet dryers · CPC title

• B41F33/0009

  Central control units · CPC title