Printer for printing on a continuous print medium

A method of saving ribbon in a thermal printer which prints upon a continuous print medium by ink transfer from a thermal print ribbon and wherein the thermal printer includes a thermal print head having energizable print elements, the method comprising the steps of:

• driving a print medium past said thermal print head at a speed which can be greater than a maximum printing speed characteristic of said thermal print head;
• driving a thermal print ribbon past said thermal print head in the same direction as said print medium at a speed substantially equal to said maximum printing speed of said thermal print head;
• providing a memory having stored therein predetermined patterns of dots;
• selectively energizing predetermined ones of said print elements of said thermal print head according to predetermined patterns of dots stored within said memory so as to transfer ink from said thermal print ribbon to said print medium in accordance with a predetermined one of said predetermined patterns of ink dots as said print medium is driven past said print head;
• and
• periodically omitting selected ink dots from said predetermined one of said predetermined patterns of ink dots formed upon said print medium when the speed of said print medium is greater than said maximum ribbon and print head speeds.

A thermal printer for printing on a continuous print medium by means of ink transfer from a thermal print ribbon, comprising:

• means defining a print medium path along which a print medium is conducted;
• a thermal print head having energizable print elements and located adjacent to said print medium path;
• means defining a print ribbon path which extends substantially in the same direction as said print medium path and along which a print ribbon is conducted such that said print ribbon is interposed between said print head and said print medium;
• ribbon drive means operable to drive said print ribbon at varying speeds along said print ribbon path;
• speed sensing means operable to sense the speed of travel of said print medium along said print medium path;
• and
• processing means, including memory means, for controlling said ribbon drive means in order to vary the speed, at which said print ribbon is driven, up to a maximum speed substantially corresponding to the maximum printing speed of said print head, for energizing selected ones of said print elements according to predetermined line patterns of dots stored within said memory means so as to cause the transfer of ink from said print ribbon to said print medium in accordance with a predetermined one of said line patterns of ink dots as said print medium moves past said print head along said print medium path, and for monitoring the speed of said print medium using said speed sensing means such that when the speed of said print medium is greater than said maximum ribbon and print head speeds, said print elements are energized such that a selected line of ink dots is omitted from said predetermined line pattern of ink dots formed upon said print medium.

A method of saving ribbon in a thermal printer which prints upon a continuous print medium by ink transfer from a thermal print ribbon and wherein the thermal printer includes a thermal print head having energizable print elements, the method comprising the steps of:

• driving a print medium past said thermal print head at a speed which can be greater than a maximum printing speed characteristic of said thermal print head;
• driving a thermal print ribbon past said thermal print head in the same direction as said print medium at a speed substantially equal to said maximum printing speed of said thermal print head;
• providing a memory having stored therein predetermined line patterns of ink dots;
• selectively energizing predetermined ones of said print elements of said thermal print head according to predetermined line patterns of dots stored within said memory so as to transfer ink from said thermal print ribbon to said print medium in accordance with a predetermined one of said predetermined line patterns of ink dots as said print medium is driven past said print head;
• and
• periodically omitting a selected line of ink dots from said predetermined one of said predetermined line patterns of ink dots formed upon said print medium when the speed of said print medium is greater than said maximum ribbon and print head speeds.