High speed thermal printer

A high speed thermal printer associated with a color video printer apparatus and comprising storing means for storing an image signal input from a signal input source on a frame-by-frame basis, image print controlling means for gradation-comparing the image signal with a predetermined gradation value on a line-by-line basis, and a thermal print head comprising a plurality of heat generating elements for printing on a printing paper by sublimating dye, said printer further comprising:

• a drum motor for transporting the printing paper;
• a reel motor for transporting a film on which the dye is coated;
• maximum data detecting means for receiving the image signal on a line-by-line basis and for detecting maximum printing gradation data from the image signal;
• motor driving means for simultaneously driving said drum motor and reel motor;
• and
• system controlling means for controlling said motor driving means to drive said drum and reel motors at a constant speed in accordance with the maximum printing gradation data detected by said maximum data detecting means.