Method and apparatus for high speed thermal printing

An electroresistive printing apparatus comprising:

• a printing station;
• at least one printing unit at said printing station, with each said printing unit having a face, and with each said face being comprised of a matrix of resistive heating elements arranged in rows and columns so as to produce a printed dot density of a predetermined number of dots per millimeter;
• means for positioning a record medium at said printing station;
• means for providing a ribbon containing heat-transferrable ink at said printing station;
• means for moving relatively said face of said printing unit, said ribbon, and said record medium into and out of printing relationship at said printing station;
• means for energizing momentarily selected ones of said heating elements in said rows when said ribbon, said record medium and said face are in said printing relationship for transferring said ink to said record medium in accordance with a pattern of data to be printed so as to partially complete the printing of said pattern;
• and
• said moving means including indexing means for providing relative movement (along a line which is substantially perpendicular to said rows) among said face, said ribbon, and said record medium when they are in said printing relationship so as to present said rows of heating elements to an unprinted portion of said record medium to enable progressively the completing of said pattern of data, whereby upon predetermined numbers of energizations of said heating elements and subsequent indexings by said indexing means, said pattern of data is completed.