Ink-jet printing process and ink-jet inks used therein
View Patent ↗The present invention relates to an improved process for wet-on-wet ink-jet printing. This invention provides a progressive dot printing ink-jet process comprising the steps of applying a first ink drop to a substrate and subsequently applying a second ink drop on to the first ink drop without intermediate solidification of the first ink drop. The first and second ink drops have a different viscosity, surface tension or curing speed. Further ink drops may be applied sequentially to the combined first and second ink drops without intermediate solidification of the first and subsequent ink drops.
1. A single pass progressive dot printing ink-jet process comprising the steps of:
applying a first UV curable ink drop to a substrate;
applying a second UV curable ink drop on to the first UV curable ink drop without intermediate solidification of the first UV curable ink drop; and
subsequently applying additional UV curable ink drops sequentially to the combined first and second UV curable ink drops without intermediate solidification of the first and second UV curable ink drops; wherein
a viscosity of the first to the additional UV curable ink drops applied varies in a graduated manner within a range of from 10 up to 30 mPa·s or a range of from 30 down to 10 mPa·s; and
a curing speed of the first to the additional UV curable ink drops applied varies in a graduated manner within a range of from 20 up to 70 m/min or a range of from 70 down to 20 m/min.
2. The single pass progressive dot printing ink-jet process according to claim 1 , wherein at least four UV curable ink drops are applied sequentially during a single pass of the substrate.
3. The single pass progressive dot printing ink-jet process according to claim 1 , wherein the first and second UV curable ink drops are different colors.
4. The single pass progressive dot printing ink-jet process according to claim 3 , wherein the UV curable ink drops are selected from cyan, magenta, yellow and black.
5. The single pass progressive dot printing ink-jet process according to claim 1 , wherein a surface tension of the first to the additional UV curable ink drops applied varies in a graduated manner within a range of from 20 up to 40 dynes/cm or a range of from 40 down to 20 dynes/cm.
6. A set of UV curable ink-jet inks suitable for use in a single pass progressive dot printing ink-jet process comprising:
at least four UV curable inks having a different viscosity, surface tension, and curing speed; wherein
the viscosity of the UV curable inks varies in a graduated manner within a range of from 10 up to 30 mPa·s or a range of from 30 down to 10 mPa·s;
the surface tension of the UV curable inks varies in a graduated manner within a range of from 20 up to 40 dynes/cm or a range of from 40 down to 20 dynes/cm; and
the curing speed of the UV curable inks varies in a graduated manner within a range of from 20 up to 70 m/min or a range of from 70 down to 20 m/min.
7. The set of UV curable ink-jet inks according to claim 6 , wherein the UV curable inks are selected from cyan, magenta, yellow and black.
8. An ink dispenser holding a set of UV curable ink-jet inks according to claim 6 .
9. A single pass progressive dot printing ink-jet process comprising the steps of:
applying a first UV curable ink drop to a substrate; and
applying a second UV curable ink drop on to the first UV curable ink drop without intermediate solidification of the first UV curable ink drop,
wherein subsequent UV curable ink drops are applied sequentially to the combined first and second UV curable ink drops without intermediate solidification of the first and second UV curable ink drops,
wherein a viscosity of the first to a last UV curable ink drop applied varies in a graduated manner within a range of from 10 up to 30 mPa·s or a range of from 30 down to 10 mPa·s.
10. A single pass progressive dot printing ink-jet process comprising the steps of:
applying a first UV curable ink drop to a substrate; and
applying a second UV curable ink drop on to the first UV curable ink drop without intermediate solidification of the first UV curable ink drop,
wherein subsequent UV curable ink drops are applied sequentially to the combined first and second UV curable ink drops without intermediate solidification of the first and second UV curable ink drops,
wherein a surface tension of the first to a last UV curable ink drop applied varies in a graduated manner within a range of from 20 up to 40 dynes/cm or a range of from 40 down to 20 dynes/cm.
11. A single pass progressive dot printing ink-jet process comprising the steps of:
applying a first UV curable ink drop to a substrate; and
applying a second UV curable ink drop on to the first UV curable ink drop without intermediate solidification of the first UV curable ink drop,
wherein subsequent UV curable ink drops are applied sequentially to the combined first and second UV curable ink drops without intermediate solidification of the first and second UV curable ink drops,
wherein a cure speed of the first to a last UV curable ink drop applied varies in a graduated manner within a range of from 20 up to 70 m/min or a range of from 70 down to 20 m/min.
12. The single pass progressive dot printing ink-jet process according to claim 9 , 10 , or 11 , wherein at least four UV curable ink drops are applied sequentially during a single pass of the substrate.
13. The single pass progressive dot printing ink-jet process according to claim 9 , 10 , or 11 , wherein the first and second UV curable ink drops are different colors.
14. The single pass progressive dot printing ink-jet process according to claim 9 , 10 , or 11 , wherein the UV curable ink drops are selected from cyan, magenta, yellow and black.
15. A set of UV curable inkjet inks suitable for use in a single pass progressive dot printing inkjet process comprising:
at least four UV curable inks having a different viscosity, wherein the viscosity of the UV curable inks varies in a graduated manner within a range of from 10 up to 30 mPa·s or a range of from 30 down to 10 mPa·s.
16. A set of UV curable inkjet inks suitable for use in a single pass progressive dot printing inkjet process comprising:
at least four UV curable inks having a different surface tension, wherein the surface tension of the UV curable inks varies in a graduated manner within a range of from 20 up to 40 dynes/cm or a range of from 40 down to 20 dynes/cm.
17. A set of UV curable inkjet inks suitable for use in a single pass progressive dot printing inkjet process comprising:
at least four UV curable inks having a different curing speed, wherein the curing speed of the UV curable inks varies in a graduated manner within a range of from 20 up to 70 m/min or a range of from 70 down to 20 m/min.
18. The ink-jet set according to claim 15 , 16 , or 17 , wherein the at least four UV curable inks include cyan, magenta, yellow and black.
19. The ink-jet set according to claim 15 , 16 , or 17 , wherein each of the at least four UV curable inks includes a cationic photoinitiator.
20. The ink-jet set according to claim 15 , 16 , or 17 , wherein each of the at least four UV curable inks includes a pigment as a colorant.
21. The ink-jet set according to claim 15 , 16 , or 17 , wherein each of the four UV curable inks includes:
a) monofunctional acrylate
15-45%;
b) polyfunctional acrylate
45-55%;
c) photoinitiators
1.0-6.0%;
d) synergist additive
<5%;
e) pigment dispersion
<3%; and
f) surfactant additive
0.01-2.0%.