System and method for efficient donor material use

A control system for a thermal printer adapted to print images by transferring donor material from patches of donor material on a donor ribbon to form an image on a receiver medium, said printer being operable to print images in a manner that exhausts a full donor patch set or in a manner that exhausts a fractional donor patch set during printing, the control system comprising:

• a controller adapted to receive a print order, to determine whether a fractional donor patch set is available for printing;
• and to cause an image to be printed using donor material from an available fractional donor patch set where at least part of the print order can be satisfied using donor material from the fractional donor patch set except where said controller determines that the available fractional donor patch set has been used to print a previous image having an average image density in a minimum portion of the image that is greater than a threshold average image density.

A control system for operating a thermal printer adapted to print images by heating and transferring donor material from donor patch sets from onto a receiver medium, the printer being operable to print images in a manner that exhausts a full donor patch set or a fractional donor patch set during printing, comprising:

• a controller for identifying one of the donor patch sets on the web as a fractional donor patch set having sufficient donor material remaining to print an image, said controller further being adapted to determine that the fractional donor patch set is not to be used for printing when the identified fractional donor patch set has been used to print an image wherein at least a minimum area of at least one donor patch has been heated to a level above a threshold level.