Ink-receptor sheet for use as a recording material

Abstract

A recording sheet for use on a digital press includes either insoluble aluminium trihydrate in the base paper or magnesium sulphate at the surface. According to a second aspect of the invention, the recording sheet includes a paper substrate having a surface treatment including a water soluble cationic substance and a water soluble binder substance.

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         42 . Use of a recording sheet in a digital printing process, said use including the steps of: 
 providing a recording sheet that includes a paper substrate having a surface treatment including a water soluble cationic substance and a water soluble binder substance,    loading the recording sheet into a digital printing press, and    printing onto the recording sheet using a digital printing process that includes transferring liquid toner onto the recording sheet by electrophotography.    
     
     
         43 . Use of a recording sheet according to  claim 42 , wherein the cationic substance is a soluble polyvalent metal salt.  
     
     
         44 . Use of a recording sheet according to  claim 43 , wherein the cationic substance is a salt of a metal from Groups II and III or the Transition Metals of the Periodic Table.  
     
     
         45 . Use of a recording sheet according to  claim 44 , wherein the cationic substance is a salt of a cation selected from the group consisting of Mg 2+ , Ca 2+ , Al 3+ , Zr 4+  and Zn 2+ .  
     
     
         46 . Use of a recording sheet according to  claim 45 , wherein the cationic substance is magnesium sulphate.  
     
     
         47 . Use of a recording sheet according to  claim 46 , wherein the amount of magnesium sulphate applied to the surface of the recording sheet is in the range 0.5-3.0 g/m 2 .  
     
     
         48 . Use of a recording sheet according to  claim 47 , wherein the amount of magnesium sulphate applied to the surface of the recording sheet is in the range 1.0-2.0 g/m 2 .  
     
     
         49 . Use of a recording sheet according to  claim 48 , wherein the amount of magnesium sulphate applied to the surface of the recording sheet is in the range 1.25-1.75 g/m 2 .  
     
     
         50 . Use of a recording sheet according to  claim 42 , wherein the cationic substance is a cationic polymer.  
     
     
         51 . Use of a recording sheet according to  claim 50 , wherein the cationic substance is a poly-quaternary amine.  
     
     
         52 . Use of a recording sheet according to  claim 42 , wherein the binder substance is selected from a group consisting of polyvinylpyrrolidone, polyvinyl alcohol, carboxylated cellulosic polymers, polyacrylic acids, hydroxylated polyacrylates, polyacrylamides, starches and gelatine.  
     
     
         53 . Use of a recording sheet according to  claim 52 , wherein the binder substance is selected from a group consisting of carboxyalkyl polymers and hydroxyalkyl polymers.  
     
     
         54 . Use of a recording sheet according to  claim 53 , wherein the binder substance is selected from a group consisting of hydroxymethyl cellulose and hydroxypropyl cellulose.  
     
     
         55 . Use of a recording sheet according to  claim 54 , wherein the binder substance comprises carboxymethyl cellulose.  
     
     
         56 . Use of a recording sheet according to  claim 52 , wherein the binder substance has a molecular weight in the range 790,000 to 1,350,000.  
     
     
         57 . Use of a recording sheet according to  claim 52 , wherein the binder substance is polyvinyl pyrrollidone having a viscosity defined by a K-value of at least 30.  
     
     
         58 . Use of a recording sheet according to  claim 57 , wherein the binder substance is polyvinyl pyrrollidone having a viscosity defined by a K-value of at least 60.  
     
     
         59 . Use of a recording sheet according to  claim 58 , wherein the binder substance is polyvinyl pyrrollidone having a viscosity defined by a K-value of at least 90.  
     
     
         60 . Use of a recording sheet according to  claim 59 , wherein the amount of polyvinyl pyrrollidone applied to the surface of the recording sheet is in the range 0.15-0.75 g/m 2 .  
     
     
         61 . Use of a recording sheet according to  claim 60 , wherein the amount of polyvinyl pyrrollidone applied to the surface of the recording sheet is in the range 0.4-0.7 g/m 2 .  
     
     
         62 . Use of a recording sheet according to  claim 61 , wherein the amount of polyvinyl pyrrollidone applied to the surface of the recording sheet is approximately 0.5 g/m 2 .  
     
     
         63 . Use of a recording sheet according to  claim 42 , in which the substances are applied to the surface of the recording sheet as an aqueous solution.  
     
     
         64 . Use of a recording sheet according to  claim 42 , in which the recording sheet has a substantially uncoated appearance.  
     
     
         65 . Use of a recording sheet according to  claim 42 , the recording sheet being suitable for use on a digital press, in a lithographic printing process, for laser printing, inkjet printing with dye and pigment based inks and hot melt imaging.  
     
     
         66 . Use of a recording sheet according to  claim 42 , wherein the recording sheet is translucent or transparent.