Spot color enhancement in a digital inkjet press

Patent metadata

Field	Value
Publication number	US-9522542-B2
Application number	US-201614996151-A
Country	US
Kind code	B2
Filing date	Jan 14, 2016
Priority date	Feb 9, 2015
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A method of enhancing spot color printing in a digital inkjet press having a fixed number of monochrome inkjet printheads, the fixed number of monochrome inkjet printheads printing inks comprising at least process colors (CMY) and a spot color, the method comprising the steps of: (a) printing a process color combination comprising a predetermined ratio of at least two process colors, the process color combination approximating the spot color; and (b) printing the spot color with the process color combination to provide an enhanced spot color.

First claim

The invention claimed is:

1. A method of enhancing spot color printing in a digital inkjet press having a fixed number of monochrome inkjet printheads, the fixed number of monochrome inkjet printheads printing inks comprising at least process colors (CMY) and a spot color, said method comprising the steps of:
printing a process color combination comprising a predetermined ratio of at least two process colors, the process color combination approximating the spot color; and
printing the spot color with the process color combination to provide an enhanced spot color,

wherein:
the spot color has a hue angle defined by h1*;
the process color combination has a hue angle defined by h2*; and
−10°≦ h 1*− h 2*≦+10°.

2. The method of claim 1 , wherein:
the spot color has a lightness value defined by L1*;
the process color combination has a lightness value defined by L2*; and
−20≦ L 1*− L 2*≦+20.

3. The method of claim 1 , wherein:
the spot color has a chroma value defined by C1*;
the enhanced spot color has a chroma value defined by C3*; and
C 3*> C 1*.

4. The method of claim 3 , wherein the digital inkjet press comprises a maximum of five printheads.

5. The method of claim 1 , wherein the spot color is overprinted or underprinted relative to the at least two process colors.

6. The method of claim 1 , wherein the spot color is printed between the at least two process colors.

7. The method of claim 1 , wherein the spot color is orange and the process colors are magenta and yellow.

8. The method of claim 1 , wherein the digital inkjet press comprises a plurality of stationary inkjet printheads aligned in a media feed direction.

9. The method of claim 8 , wherein the digital inkjet press consists of cyan (C), magenta (M), yellow (Y), black (K) and spot color (S) printheads.

10. The method of claim 1 , wherein the spot color is printed at 100% laydown and the process color combination is printed at 100% laydown.

11. The method of claim 1 , wherein each ink has a colorant loading of less than 8 wt. %.

12. The method of claim 11 , wherein each ink is an aqueous-based inkjet ink.

13. The method of claim 1 , wherein the spot color is not black.

Assignees

• Memjet Technology Ltd
• Memjet Technology Ltd

Inventors

• Scholz Marcus
• Durham Yvette

Classifications

• B41J2/2103 Primary

  Features not dealing with the colouring process per se, e.g. construction of printers or heads, driving circuit adaptations · CPC title

• B41J2/21 Primary

  for multi-colour printing · CPC title

• B41J2/2146

  for line print heads · CPC title