code coding system in this device ribbon 10 is transported through the printing device 30 the device consists of three parts the thermal printing head 36 the image code transferring mechanism solenoid 38 and the identification card 21 which receives the image code the ribbon 10 moves at a uniform speed and is in contact with the printing head 36 at the end of the head 36 is a linear array of individual heated printing elements 37 arranged to generate the image that has been transmitted to the head 36 and the pixel areas of the ribbon if the colored component 12 of the ribbon 10 is a colored thermal ink then the heat causes the colored ink to melt and bond to the white transfer coating 13 under it if the component 12 is a direct thermal coating then the heat causes the chemistry of the direct thermal coating to change color and remain bonded to the white transfer coating 13 in either case the image code is created within the thermal transfer ribbon so that it can be transferred to the identification card 21 at the next station 38 of the printing unit this thermal transfer mechanism differs from conventional thermal transfer printing units in that in conventional thermal transfer printing the thermally created image is immediately and directly transferred to the receiving substrate the printing process applying the melted colored ink directly to the receiving substrate in this invention the image is created within the ribbon before applying it to the substrate card referring to fig3 the printed image 42 is transported to the image transfer station 38 as the ribbon moves along it the path a sensor detects this image and activates the solenoid 38 which presses the thermal transfer ribbon onto the identification card.