Digital printing process and method

Abstract

Embodiments of the invention relate to a method of indirect printing with an aqueous ink formulation applied to the surface of the intermediate transfer member. Related apparatus, systems and treatment formulations are disclosed herein.

1 . An aqueous treatment formulation comprising:
 a. at least 1.5%, by weight, of at least one water soluble polymer having a solubility in water of at least 5% at 25° C.;   b. at least 5%, by weight, of a first non-ionic surfactant having a solubility in water of at least 7%, at 25° C.; and   c. a second non-ionic, silicone-containing surfactant having a solubility in water of at least 1%, at 25° C.;   d. a carrier liquid containing water, said water making up at least 55%, by weight of the aqueous treatment formulation;   said aqueous treatment formulation optionally including at least one of or both of:   v. a water absorbing agent; and vi. polyethyleneimine (PEI),   wherein said aqueous treatment formulation has all of the following properties:
 i. a static surface tension within a range of 20 and 40 mN/m at 25° C.; 
 ii. a 25° C. dynamic viscosity that is at least 10 cP; and 
 iii. a 60° C. evaporation load of at most 7.5:1, by weight. 
   
     
     
         2 . The aqueous treatment formulation of  claim 1  wherein said water soluble polymer is a polyvinyl alcohol and the aqueous treatment formulation additionally comprises said polyethyleneimine (PEI) having an average molecular weight of 200,000 to 2,000,000 g/mol. 
     
     
         3 . The aqueous treatment formulation of  claim 1 , wherein a concentration of said first non-ionic surfactant within said aqueous treatment formulation, by weight, is within the range of 6.5-18%. 
     
     
         4 . The aqueous treatment formulation of  claim 1 , wherein said second, non-ionic silicone-containing surfactant includes a polysiloxane-polyoxyalkylene copolymer, and wherein a concentration of said polysiloxane-polyoxyalkylene copolymer is at least 0.3%, at least 0.5%, at least 0.75%, or at least 1.0%, by weight, and further optionally, at most 5%, at most 4%, at most 3%, at most 2.5%, at most 2%, or at most 1.75%, by weight. 
     
     
         5 . The aqueous treatment formulation of  claim 1 , wherein said aqueous treatment formulation further includes said water absorbing agent. 
     
     
         6 - 7 . (canceled) 
     
     
         8 . The aqueous treatment formulation of any one of  claim 1 , wherein a concentration of quaternary ammonium salt within said aqueous treatment formulation, by weight, is at most 0.8%. 
     
     
         9 . The method of  claim 1 , wherein said water soluble polymer is selected from at least one of the group consisting of polyvinyl alcohol, water-soluble cellulose, polyvinylpyrrolidone (PVP), polyethylene oxide, and a water-soluble acrylate. 
     
     
         10 . (canceled) 
     
     
         11 . The method of  claim 1 , wherein a concentration of polyethyleneimine or said polyethyleneimine within said aqueous treatment formulation, by weight, is within a range of 0.1 to 1%, and wherein an average molecular weight of said polyethyleneimine is 200,000 to 3,000,000 g/mol. 
     
     
         12 . (canceled) 
     
     
         13 . The aqueous treatment formulation of  claim 1 , wherein said first non-ionic surfactant is, mainly includes, or includes a polyethoxylated sorbitan ester. 
     
     
         14 - 15 . (canceled) 
     
     
         16 . The aqueous treatment formulation of  claim 13 , wherein the HLB number of said first non-ionic surfactant is within a range of 14.5 to 20. 
     
     
         17 - 18 . (canceled) 
     
     
         19 . The aqueous treatment formulation of  claim 1 , wherein a concentration of said water soluble polymer is within a range of 2.0 to 8%. 
     
     
         20 - 22 . (canceled) 
     
     
         23 . The aqueous treatment formulation of  claim 1 , wherein said solubility in water of said at least one water soluble polymer, at 25° C., is at least 10%, by weight. 
     
     
         24 . The aqueous treatment formulation of  claim 1 , wherein said solubility in water of said first non-ionic surfactant, at 25° C., is at least 12%, by weight. 
     
     
         25 . The aqueous treatment formulation of  claim 1 , wherein said water absorbing agent is selected whereby, when said aqueous treatment solution is evaporated to form a solid film, said water absorbing agent acts as a water absorber that absorbs water from said aqueous treatment solution. 
     
     
         26 . (canceled) 
     
     
         27 . The aqueous treatment formulation of  claim 1 , wherein a concentration of said second non-ionic surfactant within said aqueous treatment formulation, by weight, is within a range of 1-18%. 
     
     
         28 - 34 . (canceled) 
     
     
         35 . method of  claim 1 , wherein functional groups within said silicone based release layer surface of the provided ITM make up at most 3%, by weight, of said addition-cured silicone material. 
     
     
         36 - 53 . (canceled) 
     
     
         54 . An article of manufacture comprising:
 (A) a quantity of the aqueous treatment formulation of  claim 1 ; and   (B) an intermediate transfer member (ITM) comprising a silicone-based release layer surface that is sufficiently hydrophilic to satisfy at least one of the following properties: (i) a receding contact angle of a drop of distilled water deposited on the silicone-based release layer surface is at most 60°; and (ii) a 10-second dynamic contact angle (DCA) of a drop of distilled water deposited on the silicone-based release layer surface is at most 108°   
     
     
         55 . The article of manufacture of  claim 54  wherein functional groups within said silicone based release layer surface of the provided ITM make up at most 3%, by weight, of said addition-cured silicone material. 
     
     
         56 . A method comprising:
 (A) providing a quantity of the aqueous treatment formulation of  claim 1 ; and   (B) applying the quantity of the aqueous treatment formulation to a silicone-based release layer surface of an intermediate transfer member (ITM), said silicone-based release layer surface being, before said applying, sufficiently hydrophilic to satisfy at least one of the following properties: (i) a receding contact angle of a drop of distilled water deposited on the silicone-based release layer surface is at most 60′; and (ii) a 10-second dynamic contact angle (DCA) of a drop of distilled water deposited on the silicone-based release layer surface is at most 108°   
     
     
         57 . The method of  claim 56  wherein functional groups within said silicone based release layer surface of the provided ITM make up at most 3%, by weight, of said addition-cured silicone material.