Direct thermal printable film and laminate

Abstract

A new direct thermal printable media includes an optically transmissive film that gives both form and protection to a layer of thermosensitive imaging material on a back surface of the film. Concentrations of heat applied to a front surface of the film form images within the thermosensitive layer that are visible through the film. A substrate is laminated to the thermosensitive layer on the back surface of the film for providing additional support independently of physical and chemical properties required for directly supporting thermosensitive imaging material.

I claim:  
     
         1 . A direct thermal printable laminate comprising: 
 a thermally transmissive film having front and back surfaces;    a thermosensitive imaging layer on said back surface of the thermally transmissive film;    said thermosensitive imaging layer having a color developing mechanism reactive to transmissions of heat through said thermally transmissive film for forming images within said thermosensitive imaging layer;    a substrate for supporting said thermally transmissive film also having front and back surfaces; and    a bond between said back surface of the thermally transmissive film and the front surface of the substrate for laminating said thermally transmissive film to said substrate.    
     
     
         2 . The laminate of  claim 1  in which said bond is formed by an adhesive layer located between said thermosensitive imaging layer and the front surface of the substrate.  
     
     
         3 . The laminate of  claim 2  in which said thermosensitive imaging layer is bonded directly to said back surface of the transmissive film and indirectly to said front surface of said substrate through the intermediacy of said adhesive layer.  
     
     
         4 . The laminate of  claim 2  in which any layers located between said thermosensitive imaging layer and said adhesive layer are successively bonded to said thermosensitive imaging layer.  
     
     
         5 . The laminate of  claim 4  further comprising a barrier layer located between said thermosensitive imaging layer and said adhesive layer for preventing migration of contaminants from said adhesive layer to said thermosensitive imaging layer.  
     
     
         6 . The laminate of  claim 2  in which said back surface of the transmissive film and said front surface of the substrate have respective surface forms, and said thermosensitive imaging layer takes the form of said back surface of the transmissive film.  
     
     
         7 . The laminate of  claim 6  in which said thermosensitive imaging layer is in contact with said adhesive layer.  
     
     
         8 . The laminate of  claim 1  in which said thermally transmissive film is a strip of flexible material supporting said thermosensitive imaging layer.  
     
     
         9 . The laminate of  claim 1  in which said thermally transmissive film has a first thickness measured between said front and back surfaces of the thermally transmissive film and said substrate has a second thickness measured between said front and back surfaces of the substrate, and said first thickness is less than said second thickness.  
     
     
         10 . The laminate of  claim 9  in which said first thickness is less than 10 microns.  
     
     
         11 . The laminate of  claim 9  in which said second thickness is more than said first surface by at least an order of magnitude.  
     
     
         12 . The laminate of  claim 9  in which said front surface of the substrate has an average peak-to-valley roughness that is larger than an average peak-to-valley roughness of said back surface of the transmissive film.  
     
     
         13 . The laminate of  claim 12  in which said thermosensitive imaging layer has an average thickness that is more than the average roughness of the back surface of the transmissive film and less than the average roughness of the front surface of the substrate.  
     
     
         14 . The laminate of  claim 13  in which said thermosensitive imaging layer is applied as a coating on said transmissive film.  
     
     
         15 . The laminate of  claim 14  further comprising a friction-reducing coating applied over said front surface of the thermally transmissive film to protect thermal print heads from abrasion.  
     
     
         16 . The laminate of  claim 15  in which said front surface of the transmissive film is receptive to inks.  
     
     
         17 . The laminate of  claim 1  in which said thermally transmissive film is also an optically transmissive film so that the images formed in the thermosensitive imaging layer are visible through said film.  
     
     
         18 . The laminate of  claim 17  in which said substrate is opaque.  
     
     
         19 . A method of direct thermal printing the laminate of  claim 1  including the step of applying concentrations of heat to said front surface of the thermally transmissive film resulting in the formation of images within said thermosensitive imaging layer.  
     
     
         20 . The method of  claim 19  in which a thermal print head is used to apply the concentrations of heat.  
     
     
         21 . The method of  claim 20  in which the images are formed in said thermosensitive imaging layer by a chemical interaction between a dye precursor and a color developer induced by the transmissions of heat through said thermally transmissive film.  
     
     
         22 . A direct thermal printable laminate comprising: 
 first and second substrates located adjacent to each other and each having first and second surfaces;    a thermosensitive imaging layer applied as a coating on said second surface of the first substrate;    said thermosensitive imaging layer having a color developing mechanism reactive to transmissions of heat through said first substrate for forming images within said thermosensitive imaging layer;    said second surface of the first substrate being bonded to said first surface of the second substrate so that said thermosensitive imaging layer is located between said first and second substrates;    said first substrate being of reduced thickness with respect to said second substrate for transmitting concentrations of heat required to form images in said thermosensitive imaging layer from a thermal print head; and    at least one of said first and second substrates being optically transmissive for viewing images formed in said thermosensitive imaging layer.    
     
     
         23 . The laminate of  claim 22  in which said second surface of the first substrate and said first surface of the second substrate have respective surface forms and said thermosensitive imaging layer takes the form of said second surface of the first substrate.  
     
     
         24 . The laminate of  claim 22  in which said first surface of the second substrate has an average peak-to-valley roughness that is larger than an average peak-to-valley roughness of said second surface of the first substrate.  
     
     
         25 . The laminate of  claim 24  in which said thermosensitive imaging layer has an average thickness that is more than the average roughness of the second surface of the first substrate and less than the average roughness of the first surface of the second substrate.  
     
     
         26 . The laminate of  claim 22  in which said thickness of the first substrate is less than 10 microns.  
     
     
         27 . The laminate of  claim 22  further comprising a friction reducing coating applied to said first surface of the first substrate to protect the thermal print head from abrasion.  
     
     
         28 . The laminate of  claim 22  further comprising an adhesive layer located between said thermosensitive imaging layer of the first substrate and said first surface of the second substrate for bonding said first and second substrates.  
     
     
         29 . The laminate of  claim 28  further comprising a barrier layer located between said thermosensitive imaging layer and said adhesive layer for preventing migration of contaminants from said adhesive layer to said thermosensitive imaging layer.  
     
     
         30 . The laminate of  claim 22  in which said first substrate is and optically transmissive film.  
     
     
         31 . The laminate of  claim 30  in which said second substrate is opaque.  
     
     
         32 . The laminate of  claim 28  in which said adhesive layer is a first adhesive layer and further comprising a second adhesive layer located adjacent to said second surface of the second substrate.  
     
     
         33 . The laminate of  claim 32  further comprising a release layer located adjacent to said first surface of the first substrate.  
     
     
         34 . The laminate of  claim 33  in which said first and second substrates unwindable together from a roll in which said second adhesive layer is in contact with said release layer.  
     
     
         35 . A method of direct thermal printing the laminate of  claim 22  including the step of applying concentrations of heat to said first surface of the first substrate resulting in the formation of images within said thermosensitive imaging layer.  
     
     
         36 . The method of  claim 35  in which a thermal print head is used to apply the concentrations of heat.  
     
     
         37 . The method of  claim 36  in which the images are formed in said thermosensitive imaging layer by a chemical interaction between a dye precursor and a color developer induced by the transmissions of heat through said first substrate.  
     
     
         38 . A self-wound direct thermal printable tape comprising: 
 a film having front and back surfaces;    a release layer on said front surface of the film;    a thermosensitive imaging layer on said back surface of the film;    said thermosensitive imaging layer having a color developing mechanism reactive to transmissions of heat through said film for forming images within said thermosensitive imaging layer;    a substrate having front and back surfaces;    a first adhesive layer on said front surface of the substrate for bonding said substrate to said film;    a second adhesive layer on said back surface of the substrate for bonding said substrate to another substrate; and    said film being unwindable together with said substrate from a roll in which said second adhesive layer is in contact with said release layer.    
     
     
         39 . The tape of  claim 38  in which said film is optically transmissive so that images formed within said thermosensitive imaging layer are visible through said film.  
     
     
         40 . The tape of  claim 39  in which any layers located between said thermosensitive imaging layer and said first adhesive layer are successively bonded to said thermosensitive imaging layer.  
     
     
         41 . The tape of  claim 40  further comprising a barrier layer located between said thermosensitive imaging layer and said first adhesive layer for preventing migration of contaminants from said first adhesive layer to said thermosensitive imaging layer.  
     
     
         42 . The tape of  claim 39  in which said thermosensitive imaging layer is bonded to said first adhesive layer.  
     
     
         43 . The tape of  claim 38  in which said film is a strip of flexible material.  
     
     
         44 . The tape of  claim 43  in which said thermosensitive imaging layer is applied as a coating on said film.  
     
     
         45 . A method of using the tape of  claim 38  including the step of laminating the tape to said another substrate by positioning said second adhesive layer in contact with said another substrate.  
     
     
         46 . A method of printing on the tape of  claim 38  including the step of applying concentrations of heat with a thermal print head to said first surface of the film resulting in the formation of images within said thermosensitive imaging layer.  
     
     
         47 . A direct thermal printable film for use with a substrate for making a direct thermal printable laminate comprising: 
 an optically and thermally transmissive film having front and back surfaces;    a layer of friction-reducing material applied to said front surface of the transmissive film;    a layer of thermosensitive imaging material applied to said back surface of the transmissive film;    said front and back surfaces having respective surface forms and said thermosensitive imaging material taking the form of said back surface of the film; and    said thermosensitive imaging material having a color developing mechanism reactive to transmissions of heat through said film for forming images within said thermosensitive imaging layer that are visible through said film.    
     
     
         48 . The film of  claim 47  in which a layer of adhesive is applied over said layer of thermosensitive imaging material for attaching the film to the substrate prior to printing.  
     
     
         49 . The film of  claim 48  in which said layer of friction-reducing material is a release material for also protecting said layer of adhesive prior to use.  
     
     
         50 . The film of  claim 49  in which said film is unwindable from a roll in which said layer of adhesive is in contact with said layer of release.  
     
     
         51 . The film of  claim 48  further comprising a layer of barrier material between said layer of thermosensitive imaging material and said layer of adhesive for preventing migration of contaminants from said layer of adhesive to said layer of thermosensitive imaging material.  
     
     
         52 . The film of  claim 48  in which said optically and thermally transmissive film has a thickness no greater than 10 microns for transmitting thermal patterns through said film.  
     
     
         53 . A method of making a direct thermal printable laminate using the direct thermal printable film of  claim 47  including the step of laminating the back surface of the transmissive film containing the layer of thermosensitive imaging material to a front surface of a substrate that does not as readily transmit heat as the transmissive film.  
     
     
         54 . The method of  claim 53  including the further step of applying a layer of adhesive between the layer of thermosensitive imaging material and the front surface of the substrate prior to said step of laminating.  
     
     
         55 . The method of  claim 54  including the further step of applying a layer of barrier material over said layer of thermosensitive imaging material prior to said step of laminating.  
     
     
         56 . A direct thermal printable film comprising: 
 a thermally transmissive film having front and back surfaces;    a layer of thermosensitive imaging material applied to said back surface of the transmissive film;    said thermosensitive imaging material having a color developing mechanism reactive to transmissions of heat through said film for forming images within said thermosensitive imaging layer; and    said thermally transmissive film having a thickness no greater than 10 microns to permit transfers of heat from a direct thermal print head through said thermally transmissive film for forming images within said thermosensitive imaging layer.    
     
     
         57 . The film of  claim 56  in which said thermally transmissive film is also optically transmissive so that the images within said thermosensitive imaging layer are visible through said film.  
     
     
         58 . The film of  claim 56  further comprising a layer of friction-reducing material applied to said front surface of the transmissive film.  
     
     
         59 . The film of  claim 56  in which said front and back surfaces have respective surface forms and said thermosensitive imaging material takes the form of said back surface of the film.  
     
     
         60 . The film of  claim 56  in which said film is windable and unwindable from a roll for use in a laminating machine for joining said film to another substrate.  
     
     
         61 . A method of making a direct thermal printable laminate comprising the steps of: 
 feeding a film of thermally transmissive material having front and back surfaces through a coating machine;    applying a coating of thermosensitive imaging material on the back surface of the film so that transmissions of heat through the film form images within the thermosensitive imaging material;    feeding a substrate having front and back surfaces through a coating machine;    applying a coating of adhesive between the coating of thermosensitive imaging material and the front surface of the substrate; and    laminating the film and the substrate together so that the back surface of the film is adjacent to the front surface of the substrate.    
     
     
         62 . The method of  claim 61  in which said step of applying a coating of adhesive includes applying the coating to the front surface of the substrate prior to laminating the film and substrate together.  
     
     
         63 . The method of  claim 61  including the further step of dividing the film into narrower strips following said step of applying the thermosensitive imaging material and before said step of laminating.  
     
     
         64 . The method of  claim 63  including the further steps of winding the narrower strips into rolls and unwinding one of the narrower strips together with unwinding a roll of the substrate before said step of feeding the substrate.  
     
     
         65 . The method of  claim 61  including the further step of applying a barrier coating over the coating of thermosensitive imaging material for preventing migration of contaminants from the coating of adhesive to the coating of thermosensitive imaging material.  
     
     
         66 . The method of  claim 61  including the further step of applying a friction-reducing coating to said front surface of the film to reduce abrasion with a thermal print head.  
     
     
         67 . The method of  claim 61  including the further step of applying a coating of adhesive on the back surface of the substrate.  
     
     
         68 . The method of  claim 67  including the further step of applying a coating of release on the front surface of the film.  
     
     
         69 . A method of making a direct thermal printable laminate comprising the steps of: 
 feeding a film of thermally transmissive material having front and back surfaces through a processing machine, said film having a coating of thermosensitive imaging material on the back surface of the film;    feeding a substrate having front and back surfaces through the processing machine, said substrate having a thickness greater than a thickness of said film; and    laminating the film and the substrate together so that the back surface of the film containing the thermosensitive imaging material is adjacent to the front surface of the substrate.    
     
     
         70 . The method of  claim 69  including the further step of applying a coating of adhesive between the thermosensitive imaging material and the front surface of the substrate prior to said step of laminating.  
     
     
         71 . The method of  claim 69  in which said film has a thickness no greater than 10 microns to support transmissions of heat through the film to form images within the thermosensitive imaging material.  
     
     
         72 . The method of  claim 69  including the further steps of separately unwinding the film and the substrate from separate rolls prior to said steps of feeding the film and substrate through the processing machine.  
     
     
         73 . The method of  claim 72  in which the coating of thermosensitive imaging material is applied in advance of said step of unwinding the film.  
     
     
         74 . The method of  claim 69  in which the substrate is a first of two substrates and including the further step of feeding a second substrate having front and back surfaces through a processing machine, said second substrate also having a thickness greater than the thickness of said film.  
     
     
         75 . The method of  claim 74  in which said step of laminating includes laminating a first length portion of the film to the first substrate and including the further step of laminating a second length portion of the film to the second substrate so that the back surface of the film containing the thermosensitive imaging material is adjacent to the front surface of the second substrate.