Tunable surfactants in dampening fluids for digital offset ink printing applications
AssigneesXerox Corporation, Palo Alto Research Incorporated
InventorsNaveen Chopra, Peter Gordon Odell, Steven E. Ready, Eric Peeters, Timothy D. Stowe, Ashish Pattekar, David K. Biegelsen
Life of this patent
Estimating the term…
Abstract
A dampening fluid useful in offset ink printing applications contains water and a surfactant whose structure can be altered. The alteration in structure aids in reducing accumulation of the surfactant on the surface of an imaging member. The surfactant can be decomposed, switched between cis-trans states, or polymerizable with ink that is subsequently placed on the surface.
Claims14
A method for cleaning an imaging member during offset lithographic printing, comprising:
- coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
- after an ink transfer from the imaging member and before a subsequent latent image forming step on the imaging member, exposing the imaging member to light or heat to alter the structure of the surfactant across the imaging member;
- and
- removing the surfactant from the imaging member, wherein the surfactant includes a cis-trans isomer having a dipole moment.
A method for cleaning an imaging member during offset lithographic printing, comprising:
- coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
- exposing the imaging member to light or heat to alter the structure of the surfactant;
- and
- removing the surfactant from the imaging member, wherein the surfactant includes a cis-trans isomer having a dipole moment, the cis-trans isomer including an azobenzene compound having the structure of Formula (III):
- wherein R1, R2, R3, R4, R5, and R6 are independently selected from hydrogen, carboxylic acid, amino, thiol, cyano, nitro, halogen, vinyl, alkoxy, trialkylammoniumalkoxy, sulfonic acid, phosphate ester, aldehyde, amide, urea, carbonate, carbonate, alkyl, polyoxyalkylene, and ester;
- and wherein R1 is different from R4.
A method for cleaning an imaging member during offset lithographic printing, comprising:
- coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
- exposing the imaging member to light or heat to alter the structure of the surfactant;
- and
- removing the surfactant from the imaging member, wherein the surfactant includes a cis-trans isomer having a dipole moment, the cis-trans isomer including an azobenzene compound having the structure of Formula (III-a):
- wherein R1 is selected from hydroxyl, amino, cyano, nitro, halogen, vinyl, alkoxy, sulfonic acid, aldehyde, and ester.
A method for cleaning an imaging member during offset lithographic printing, comprising:
- coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
- exposing the imaging member to light or heat to alter the structure of the surfactant;
- and
- removing the surfactant from the imaging member, wherein the surfactant includes a cis-trans isomer having a dipole moment, the cis-trans isomer including an azobenzene compound having the structure of Formula (III-b):
- wherein Rb is alkyl having 2 to 6 carbon atoms;
- and p is an integer from 1 to 10.
A method for cleaning an imaging member during offset lithographic printing, comprising:
- coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
- exposing the imaging member to light or heat to alter the structure of the surfactant;
- and
- removing the surfactant from the imaging member, wherein the surfactant includes a cis-trans isomer having a dipole moment, the cis-trans isomer including an azobenzene compound having the structure of Formula (III-c):
Dependencies are inferred from the claim text.