Method and system for thermal graphic printing

Abstract

A method of thermally transferring colorant from a movable ribbon onto printable areas of a thermal print receptive sheeting. The method includes arranging a print head so that its length is substantially parallel to the direction of travel of the thermal print receptive sheeting and transferring colorant from the movable ribbon to the sheeting as the sheeting is stationary and the thermal print head is moved in a second direction substantially normal to the length of the thermal print head. The system includes a thermal print head, a transport for moving the thermal print receptive sheeting past the thermal print head in the first direction, and a mechanism that moves the print head in a second direction normal to the first direction when the print head is transferring colorant onto the sheeting.

What is claimed is:  
     
       1. A method of thermally transferring colorant from a moving ribbon on to printable areas of a thermal print receptive sheeting, comprising the steps of: 
       a) moving a thermal print receptive sheeting past a thermal print head, where the thermal print head is elongate and has a length L of at least one centimeter that extends substantially in a first direction; and  
       b) transferring the colorant from the moving ribbon to the thermal print receptive sheeting while moving the thermal print head in a second direction substantially normal to the first direction wherein the sheeting moves in the first direction past the thermal print head and wherein the sheeting movement is halted while transferring the colorant from the ribbon to the thermal print receptive sheeting.  
     
     
       2. The method of  claim 1 , wherein the thermal print receptive sheeting has a width of at least 16 centimeters. 
     
     
       3. The method of  claim 2 , wherein the thermal print receptive sheeting has a width of at least 38 centimeters. 
     
     
       4. The method of  claim 3 , wherein the thermal print receptive sheeting has a width of at least 50 centimeters. 
     
     
       5. The method of  claim 1 , wherein the thermal print receptive sheeting has a width of at least 46 centimeters. 
     
     
       6. The method of  claim 1 , wherein the colorant includes a binder that contains a pigment, a dye, or a combination thereof. 
     
     
       7. The method of  claim 1 , wherein the thermal print head transfers colorant from the movable ribbon to the thermal print receptive sheeting by the simultaneous application of heat and pressure. 
     
     
       8. The method of  claim 1 , wherein the length L is 4 to 27 centimeters. 
     
     
       9. The method of  claim 8 , wherein the length L is about 10 or about 16 centimeters. 
     
     
       10. The method of  claim 1 , further comprising sensing the position of the thermal print relative to the sheeting. 
     
     
       11. The method of  claim 1 , wherein when the print head is disengaged from the sheeting, the ribbon advance simultaneously ceases. 
     
     
       12. The method of  claim 1 , further comprising the step of  A method of thermally transferring colorant from a moving ribbon on to printable areas of a thermal print receptive sheeting, comprising the steps of: 
         a )  moving a thermal print receptive sheeting past a thermal print head, where the thermal print head is elongate and a length L of at least one centimeter that extends substantially in a first direction;    
         b )  transferring the colorant from the moving ribbon to the thermal print receptive sheeting while moving the thermal print head in a second direction substantially normal to the first direction wherein the sheeting moves in the first direction past the thermal print head and wherein the sheeting movement is halted while transferring the colorant from the ribbon to the thermal print receptive sheeting; and    
         c ) applying a polymeric film layer to the thermal print receptive sheeting after colorant transfer.  
     
     
       13. The method of  claim 1 , wherein the thermal print receptive sheeting is a retroreflective sheeting. 
     
     
       14. The method of  claim 13 , wherein the ribbon comprises a resin-based binder. 
     
     
       15. The method of  claim 13 , wherein the thermal print receptive sheeting is a cube corner retroreflective sheeting or a beaded lens retroreflective sheeting. 
     
     
       16. The method of  claim 1 , wherein the thermal print head comprises heatable resistive elements for supplying localized heat that causes the transfer of colorant from the ribbon to the sheeting. 
     
     
       17. The method of  claim 1 , further comprising the step of disengaging the thermal print head when the thermal print head is moved in the second direction with no colorant is  being transferred to a printable area of the sheeting, the ribbon ceasing to advance during periods of no colorant transfer. 
     
     
       18. The method of  claim 1 , wherein the thermal print head is a graphics-based thermal print head. 
     
     
       19. A method of transferring colorant from a moving ribbon on to a printable area of a thermal print receptive sheeting, the method comprising the steps of: 
       (a) moving a thermal print receptive sheeting in a first direction past a thermal print head that is elongate, that has a length L of at least one centimeter, and that extends in the first direction;  
       (b) halting movement of the sheeting; and then  
       (c) moving the thermal print head in a second direction normal to the first direction; and  
       (d) transferring colorant from the moving ribbon to the thermal print receptive sheeting.  
     
     
       20. A method of thermally transferring colorant from a moving ribbon onto printable areas of a thermal print receptive sheeting, comprising the steps of: 
         a )  moving a thermal print receptive sheeting in a first direction past a thermal print head, wherein the thermal print head is elongate and has a length L of at least one centimeter that extends substantially in the first direction; and    
         b )  transferring colorant from the moving ribbon to the thermal print receptive sheeting while halting the sheeting movement and moving the thermal print head in a second direction substantially normal to the first direction.   
     
     
       21. A method according to  claim 20 , wherein the print head comprises a graphics- based print head with a resolution of at least about  75  dots per lineal centimeter.   
     
     
       22. A method according to  claim 21 , wherein during the transferring step the print head maintains pressure against a platen in the form of a platform. 
     
     
       23. A method according to  claim 21 , wherein the colorant forms graphics- based indicia on the sheeting.   
     
     
       24. A method according to  claim 20 , further comprising sensing the position of the print head relative to the sheeting. 
     
     
       25. A method of thermally transferring colorant from a moving ribbon onto printable areas of a thermal print receptive sheeting, comprising the steps of: 
         a )  moving a thermal print receptive sheeting in a first direction past a thermal print head, wherein the thermal print head is elongate and has a length L of at least one centimeter that extends substantially in the first direction; and    
         b )  transferring colorant from the moving ribbon to the thermal print receptive sheeting while halting the sheeting movement and moving the thermal print head in a second direction substantially normal to the first direction, wherein movement of the ribbon ceases when the print head encounters an area of sufficient size on the sheeting that is not destined to have colorant transferred to it and wherein the print head continues to move across the sheeting in the second direction to an area that is destined to have colorant transferred to it.   
     
     
       26. A method according to  claim 20 , wherein the sheeting comprises a signage article. 
     
     
       27. A method according to  claim 20 , comprising a cross web graphic printing system. 
     
     
       28. A method according to  claim 20 , wherein a single width of ribbon suffices for printing on varying widths of sheeting. 
     
     
       29. A method according to  claim 20 , wherein ribbon is used in proportion to the width of sheeting being printed. 
     
     
       30. A method according to  claim 20 , wherein more than one print operation cycle is employed to complete formation of indicia on the sheeting. 
     
     
       31. A method according to  claim 20 , wherein indicia of more than one color are applied to the sheeting using a single print head. 
     
     
       32. A method according to  claim 31 , wherein after the transfer of a first colorant from a first moving ribbon to the sheeting, a differently colored ribbon is substituted for the first moving ribbon and colorant is transferred from the differently colored ribbon to the sheeting. 
     
     
       33. A method of thermally transferring colorant from a moving ribbon onto printable areas of a thermal print receptive sheeting, comprising one or more print operation cycles comprising the steps of: 
         a )  moving the sheeting in a first direction past a thermal print head having a row of heating elements with a resolution of at least about  75  dots per lineal centimeter and a length L of at least about one centimeter that extends substantially in the first direction; and    
         b )  ceasing movement of the sheeting in the first direction, moving the print head against a platen in the form of a platform in a second direction substantially normal to the first direction, and transferring colorant from the moving ribbon to the sheeting;    
         thereby forming graphics - based indicia on the sheeting.   
     
     
       34. A method according to  claim 33 , wherein indicia of more than one color are applied to the sheeting using a single print head and more than one print operation cycle. 
     
     
       35. A method according to  claim 34 , wherein after the transfer of a first colorant from a first moving ribbon to the sheeting, a differently colored ribbon is substituted for the first moving ribbon and colorant is transferred from the differently colored ribbon to the sheeting. 
     
     
       36. A method of thermally transferring colorant from a moving ribbon onto printable areas of a thermal print receptive sheeting, comprising the steps of: 
         a )  moving the sheeting past a thermal print head having a row of heating elements with a resolution of at least about  75  dots per lineal centimeter and a length L of at least one centimeter that extends substantially in the direction of movement of the sheeting; and    
         b )  moving the print head across the sheeting in a direction substantially normal to such direction of movement of the sheeting and transferring colorant from the moving ribbon to the sheeting while movement of the sheeting ceases.   
     
     
       37. A method according to  claim 36 , wherein when transferring colorant the print head maintains pressure against a platen in the form of a platform. 
     
     
       38. A method according to  claim 36 , wherein indicia of more than one color are applied to the sheeting using a single print head. 
     
     
       39. A method according to  claim 36 , wherein after the transfer of a first colorant from a first moving ribbon to the sheeting, a differently colored ribbon is substituted for the first moving ribbon and colorant is transferred from the differently colored ribbon to the sheeting. 
     
     
       40. A method of thermally transferring colorant from a moving ribbon onto printable areas of a thermal print receptive sheeting, comprising the steps of: 
         a )  moving the sheeting past a thermal print head having a row of heating elements with a resolution of at least about  75  dots per lineal centimeter and a length L of at least one centimeter that extends substantially in the direction of movement of the sheeting; and    
         b )  moving the print head across the sheeting in a direction substantially normal to such direction of movement of the sheeting and transferring colorant from the moving ribbon to the sheeting while movement of the sheeting ceases, wherein movement of the ribbon ceases when the print head encounters an area of sufficient size on the sheeting that is not destined to have colorant transferred to it and wherein the print head continues to move across the sheeting to an area that is destined to have colorant transferred to it.   
     
     
       41. A method according to  claim 36 , wherein the print head has a row of heating elements with a length L of about  10  centimeters.