Apparatus and method for increasing the productivity of a thermal printing apparatus for the production of finely detailed images of photographic quality

Thermal printing apparatus comprising:

• a laser for producing light spots;
• scanning means for scanning light spots along a line at a selected scanning speed;
• positioning means for positioning a dye donor element and a closely adjacent receiver element to be scanned by the laser light spots, the dye donor element having a thermal power level sensitivity above which the dye is transferred to print as dye pixels on the receiver element;
• means for supplying an image bearing information signal comprising a plurality of print data words;
• means for successively storing print data words and for determining intervals of time corresponding to a respective weighted value of each data word, said respective weighted value being determined by a processor;
• and
• laser control and drive means for turning the laser on to an optimum full-on power level above the level at which dye of a donor element transfers,
• means for controlling the turning on and off of the laser control and drive means such that the laser is full-on for time intervals linearly related to the weighted values of the data words;
• means for determining a time interval for each of said data words in a preselected portion of said data words and selecting from said time intervals a maximum time interval;
• means for determining a scanning speed with said maximum time intervals as a selected maximum duty cycle;
• and
• means for operating said scanning means at the determined scanning speed.

The method of operating a printing apparatus comprising means for producing light spots, scanning means for scanning said light spots along a line at a selected scanning speed, and positioning means for positioning a recording element sensitive to said light spots to be scanned by the light spots and exposing said recording element thereby;

• the method comprising the steps of:
• supplying an image bearing information signal comprising a plurality of print data words;
• successively storing print data words and determining intervals of time corresponding to a respective weighted value of each data word, said respective weighted value being determined by a processor;
• turning the light spot producing means on to an optimum full-on power level above the level at which said recording element is exposed and turning the spot producing means off,
• controlling the turning on and off of the light spot producing means so that the light producing means is full-on for time intervals linearly related to the weighted values of the data words;
• determining a time interval for each of said data words in a preselected portion of said data words and selecting from said time intervals a maximum time interval;
• determining a scanning speed, said scanning speed being equal to a distance containing said preselected portion of said data words;
• divided by the number of data words in said preselected portion times the maximum time interval;
• and
• operating said scanning means at the determined scanning speed.

The method of operating a thermal printing apparatus comprising a laser for producing light spots, scanning means for scanning light spots along a line at a selected scanning speed, and positioning means for positioning a dye donor element and a closely adjacent receiver element to be scanned by the laser light spots, the dye donor element having a thermal power level sensitivity above which the dye is transferred to print as dye pixels on the receiver element;

• the method comprising the steps of:
• supplying an image bearing information signal comprising a plurality of print data words;
• successively storing print data words and determining intervals of time corresponding to a respective weighted value of each data word, said respective weighted value being determined by a processor;
• turning the laser on to an optimum full-on power level above the level at which dye of a donor element transfers and turning the laser off,
• controlling the turning on and off of the laser such that the laser is full-on for time intervals linearly related to the weighted values of the data words;
• determining a time interval for each of said data words in a preselected portion of said data words and selecting from said time intervals a maximum time interval;
• determining a scanning speed, said scanning speed being equal to a distance containing said preselected portion of said data words;
• divided by the number of data words in said preselected portion times the maximum time interval;
• and
• operating said scanning means at the determined scanning speed.