Fast-drying, radiofrequency-activatable inkjet inks and methods and systems for their use
View Patent ↗The present invention provides methods of drying radiofrequency-activatable inkjet inks, methods for customizing the radiofrequency parameters of an RF source based on pre-selected printing conditions, and methods for selecting or formulating an RF inkjet ink composition based on pre-selected printing conditions and/or printing equipment. The invention further provides radiofrequency-activatable inks having customized radiofrequency susceptibility profiles and to sets of such radiofrequency-activatable inks.
1. A method for modifying RF inkjet ink compositions, the method comprising the steps of:
(a) providing a first inkjet ink comprising a first RF susceptor, the first inkjet ink having a first RF susceptibility;
(b) modifying the RF susceptibility of the first inkjet ink by adding an effective amount of a second RF susceptor to the first inkjet ink to provide a second inkjet ink having a second RF susceptibility;
(c) applying the second inkjet ink to a substrate; and
(d) exposing the substrate and applied inkjet ink to an effective amount of RF radiation to dry the applied inkjet ink.
2. The method of claim 1 , wherein the RF radiation has a frequency of about 100 kHz to about 1 GHz.
3. The method of claim 1 , wherein the RF radiation has a power of about 1 to 500 W.
4. The method of claim 1 , wherein the second inkjet ink comprises a colorant, and a polar carrier, and further wherein the total amount of RF susceptor is present in the second inkjet ink in an amount of about 0.1 to 10 wt. %.
5. The method of claim 1 , wherein the second RF susceptor comprises a RF-activatable acrylic acid copolymer.
6. A method for modifying a plurality of RF inkjet ink compositions comprising the steps of:
(a) providing a plurality of initial inkjet inks, wherein at least one of the plurality of inkjet inks comprises an RF susceptor having an initial RF susceptibility;
(b) modifying the RF susceptibility of the initial inkjet inks by adding an effective amounts of a second RF susceptors to the initial inkjet inks to provide a plurality of RF-modified inkjet inks having modified RF susceptibilities such that an effective amount of RF energy needed to dry any one of the plurality of RF-modified inkjet inks is the same as an effective amount of RF energy needed to dry all of the plurality of RF-modified inkjet inks;
(c) applying the plurality of RF-modified inkjet inks to a substrate; and
(d) exposing the substrate to an effective amount of RF energy to dry the plurality RF-modified inkjet inks on the substrate.
7. A method of claim 1 , wherein the second inkjet ink has a dielectric loss value of 1000-20,000 at a frequency of 30 MHz.
8. A method of claim 1 , wherein the second inkjet ink has a dielectric loss value of 200-5,000 at a frequency of 60 MHz.
9. A method of claim 6 , wherein the plurality of RF-modified inkjet inks have a dielectric loss value of 1000-20,000 at a frequency of 30 MHz.
10. A method of claim 6 , wherein the plurality of RF-modified inkjet inks have a dielectric loss value of 200-5,000 at a frequency of 60 MHz.
11. The method of claim 1 , wherein the providing a first inkjet ink comprises purchasing a commercially available inkjet ink.
12. The method of claim 6 , wherein the providing a plurality of inkjet inks comprises purchasing a plurality of commercially available inkjet inks.
13. The method of claim 12 , wherein the plurality of commercially available inkjet inks are contained within a single cartridge.
14. The method of claim 1 , wherein the second RF susceptor is an ionomer.
15. The method of claim 6 , wherein the second RF susceptors are ionomers.
16. The method of claim 1 , wherein the first RF susceptor and the second RF susceptor are the same.
17. The method of claim 1 , wherein the first RF susceptor and the second RF susceptor are different.
18. The method of claim 6 , wherein the plurality of inkjet inks are contained within a single inkjet ink cartridge.
19. The method of claim 6 , wherein the plurality of inkjet inks comprise a plurality of colors.