Printer apparatus and laminating method

Abstract

A printer apparatus including a printing-medium conveying unit conveying a printing medium, a sheet conveying unit conveying a thermal transfer sheet having an image protecting layer to be thermally transferred onto an image formed on the printing medium, a thermal head with heating elements linearly arranged in a direction orthogonal to a conveyance direction of the printing medium, and a control unit driving and controlling the thermal head. For selectively applying different amounts of thermal energy to the heating elements to form an uneven pattern on the image protecting layer thermally transferred onto the image on the printing medium, the control unit randomly divides a row of the heating elements into heating element groups each including at least two adjacent heating elements, applies the same amount of thermal energy to heating elements in the same heating element group, and applies different amounts of thermal energy to adjacent heating element groups.

1 . A printer apparatus comprising:
 printing-medium conveying means for conveying a printing medium;   sheet conveying means for conveying a thermal transfer sheet having at least an image protecting layer to be thermally transferred onto an image formed on the printing medium;   a plurality of heating elements;   a thermal head in which the heating elements are linearly arranged in a direction orthogonal to a conveyance direction in which the printing medium is conveyed; and   control means for driving and controlling the thermal head,   wherein, for selectively applying different amounts of thermal energy to the heating elements in the thermal head so as to form an uneven pattern on the image protecting layer thermally transferred onto the image formed on the printing medium, the control means randomly divides a row of the heating elements in the thermal head into heating element groups each including at least two adjacent heating elements, applies the same amount of thermal energy to heating elements included in the same heating element group, and applies different amounts of thermal energy to respective adjacent heating element groups.   
   
   
       2 . The printer apparatus according to  claim 1 , wherein the control means applies the same amount of thermal energy to each heating element of the thermal head in at least two adjacent printing lines. 
   
   
       3 . The printer apparatus according to  claim 1 , wherein two different amounts of thermal energy are applied to the respective adjacent heating element groups. 
   
   
       4 . The printer apparatus according to  claim 3 , wherein, in the uneven pattern on the printing medium, an area ratio between a recessed portion and a raised portion formed by application of the respective two different amounts of thermal energy is in the range of 4:6 to 6:4. 
   
   
       5 . A laminating method for forming, by selectively applying different amounts of thermal energy to heating elements in a thermal head, an uneven pattern on an image protecting layer thermally transferred onto an image formed on a printing medium by thermal transfer, the laminating method comprising the steps of:
 randomly dividing, for each printing line of the printing medium, a row of the heating elements in the thermal head into heating element groups each including at least two adjacent heating elements;   applying the same amount of thermal energy to heating elements included in the same heating element group; and   applying different amounts of thermal energy to respective adjacent heating element groups.   
   
   
       6 . A printer apparatus comprising:
 a printing-medium conveying unit configured to convey a printing medium;   a sheet conveying unit configured to convey a thermal transfer sheet having at least an image protecting layer to be thermally transferred onto an image formed on the printing medium;   a plurality of heating elements;   a thermal head in which the heating elements are linearly arranged in a direction orthogonal to a conveyance direction in which the printing medium is conveyed; and   a control unit configured to drive and control the thermal head,   wherein, for selectively applying different amounts of thermal energy to the heating elements in the thermal head so as to form an uneven pattern on the image protecting layer thermally transferred onto the image formed on the printing medium, the control unit randomly divides a row of the heating elements in the thermal head into heating element groups each including at least two adjacent heating elements, applies the same amount of thermal energy to heating elements included in the same heating element group, and applies different amounts of thermal energy to respective adjacent heating element groups.