Methods for inkjet varnishing

Patent metadata

Field	Value
Publication number	US-9156276-B2
Application number	US-201314404654-A
Country	US
Kind code	B2
Filing date	Jun 17, 2013
Priority date	Jul 6, 2012
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

A method for inkjet varnishing a substrate includes the steps of jetting a micro-pattern of a varnish having a viscosity of less than 30 mPa·s at 45° C. and at a shear rate of 30 s −1 to a portion of the substrate by one or more printheads having nozzles with a nozzle diameter of no more than 30 μm, and at least partially curing the micro-pattern within 500 milliseconds after jetting to provide a micro-roughness to the portion of the substrate.

First claim

The invention claimed is:

1. A method for inkjet varnishing a substrate, the method comprising the steps of:
jetting a micro-pattern of a varnish having a viscosity of less than 30 mPa·s at 45° C. and at a shear rate of 30 s −1 to a portion of the substrate using one or more print heads including nozzles having a nozzle diameter of no more than 30 μm; and
at least partially curing the micro-pattern within 500 milliseconds after jetting the micro-pattern to provide a micro-roughness to the portion of the substrate.

2. The method according to claim 1 , wherein the varnish includes a yellow colour pigment having an average particle size of less than 200 nm as determined by laser diffraction and/or a photoyellowing photoinitiator.

3. The method according to claim 2 , wherein the photoyellowing photoinitiator is a thioxanthone photoinitiator.

4. The method according to claim 1 , wherein the varnish includes at least 20 wt % of a vinylether acrylate based on a total weight of the varnish.

5. The method according to claim 1 , wherein the varnish is jetted by the one or more print heads including nozzles having a nozzle diameter of no more than 22 μm.

6. The method according to claim 1 , wherein the micro-pattern includes a plurality of varnish drops having a first drop size and a plurality of varnish drops having a second drop size larger than the first drop size.

7. The method according to claim 1 , wherein the micro-pattern is a random pattern.

8. The method according to claim 1 , wherein the micro-pattern covers 40% to 80% of the portion of the substrate.

9. The method according to claim 1 , wherein the varnish contains no or less than 0.1 wt % of particulate matter based on a total weight of the varnish that has an average size larger than 10% of the nozzle diameter as measured by laser diffraction.

10. The method according to claim 1 , wherein the substrate is a print of one or more radiation curable inkjet inks.

11. The method according to claim 10 , further comprising the step of:
using image data in the print to determine a location on the substrate to jet the micro-pattern of the varnish.

12. The method according to claim 10 , wherein the micro-pattern is jetted on a portion of the print having a highest amount of radiation curable inkjet ink per unit of surface area.

13. The method according to claim 1 , wherein the micro-pattern of the varnish is fully cured in the at least partially curing step.

14. The method according to claim 1 , wherein the varnish is jetted by a single pass inkjet printer.

15. A varnished substrate obtained by the method according to claim 1 .

Assignees

• Agfa Graphics Nv

Inventors

• De Meutter Stefaan
• Van Dyck Geert
• Tilemans David

Classifications

• B41J2/2114 Primary

  Ejecting specialized liquids, e.g. transparent or processing liquids (B41J2/211 takes precedence) · CPC title

• B41M7/0081

  using electromagnetic radiation or waves, e.g. ultraviolet radiation, electron beams · CPC title

• B41M7/0045

  using protective coatings or film forming compositions cured by mechanical wave energy, e.g. ultrasonics, cured by electromagnetic radiation or waves, e.g. ultraviolet radiation, electron beams, or cured by magnetic or electric fields, e.g. electric discharge, plasma · CPC title

• B41L23/24

  Print-finishing devices, e.g. for glossing prints · CPC title

• B41M7/02 Primary

  Dusting {, e.g. with an anti-offset powder for obtaining raised printing such as by thermogravure (B41M7/0027, B41M7/0036, B41M7/0045, B41M7/0054, B41M7/0072, B41M7/0081, B41M7/009 take precedence); Varnishing (devices for treating the surfaces of sheets, webs, or other articles in connection with printing B41F23/00, B41L23/00)} · CPC title