Method and apparatus for printing on sheet material
AssigneeGerber Scientific Products, Inc.
InventorCharles M. Hevenor
Life of this patent
Estimating the term…
Abstract
A thermal printer carries out printing operations to produce images in multiple colors in response to a printing program. In order to eliminate distortions and to insure registration of colors in the printed image, a printer controller eliminates backlash in the drive mechanism at the beginning of each printing operation.
Claims17
A printing apparatus for printing in multiple colors on sheet material comprising:
- a printhead responsive to a printing program defining a printing operation for placing a printed image on a sheet material;
- a donor web bearing a printing ink of one selected color, the web being replaceable to permit printing in other colors;
- means for supporting the donor web bearing printing ink between the printhead and the sheet material to enable the printhead to transfer the ink selectively from the web to the sheet material;
- drive means coupled with the printhead and the sheet material for moving the printhead and the sheet material relative to one another in a printing direction during a printing operation to place the printed image on the sheet material;
- and
- controller means connected with the printhead and the drive means and responsive to the printing program for controlling the operation of the printhead and the drive means to print a multiple color image long the sheet material relative to an origin point defined in the printing program and located at the beginning of the image in the printing direction,
- the controller means also including backlash elimination means actuating the drive means and displacing the printhead and sheet material relative to one another in the printing direction by an incremental amount to the origin point with each replacement of a donor web.
A printing apparatus for printing in multiple colors on a strip of sheet material comprising:
- a printhead;
- a donor web bearing a printing ink of at least one selected color, the web being replaceable to permit printing in different colors;
- means for supporting the donor web bearing the printing ink between the printhead and the strip of sheet material to enable the printhead to transfer ink selectively from the web to the sheet material;
- drive means for engaging a strip of sheet material and moving the strip longitudinally in a printing direction relative to the printhead;
- and
- controller means coupled to the printhead and the drive means and responsive to a printing program for controlling both the printhead and the drive means to print a multiple color image longitudinally along the strip of sheet material in the printing direction relative to origin point defined in the printing program and located at the beginning of the image,
- the controller means including backlash elimination means causing the drive means to reverse the movement of the sheet material and move the origin point back to the printhead and then to advance the strip of sheet material at least incrementally relative to the printhead in the printing direction prior to the start of printing on the material after each replacement of a donor web.
A printing apparatus for printing as defined in claim 6 wherein:
- the drive means engages and moves the strip of sheet material back and forth relative to the printhead;
- the controller means controls the back and forth movement of the strip to cause the strip to make multiple passes by the printhead in response to the printing program;
- and
- the backlash elimination means causes the drive means to reverse the movement of the sheet material and move the origin point back to the printhead and then to advance the strip of sheet material incrementally relative to the printhead in the printing direction prior to the beginning of each pass by the printhead.
A method of printing multiple color images defined in a printing program on sheet material in a machine controlled by the program and having a printhead, a donor web bearing a printing ink of at least one selected color, the donor web being replaceable to permit printing in different colors, the donor web and the sheet material being supported to enable the printhead to transfer the ink selectively from the web to the sheet material, and drive means for moving the printhead and sheet material relative to one another in one direction during a printing operation comprising the steps of:
- selectively energizing the printhead and the drive means in response to the printing program to move the printhead and sheet material relative to one another in the one direction and transfer ink from one donor web bearing ink of one selected color to the sheet material to print one color component of an image on the sheet material relative to an origin point defined in the printing program;
- energizing the drive means to move the printhead and sheet material relative to one another in the direction opposite to the one direction by an amount greater than the length of the image in the one direction;
- replacing the one donor web bearing ink of one selected color with another donor web bearing ink of another selected color;
- energizing the drive means upon replacement of the one donor web to move the printhead and sheet material relative to one another by at least an incremental amount in the one direction to remove backlash in the drive means and then
- selectively energizing the printhead and the drive means in response to the printing program to move the printhead and sheet material relative to one another in the one direction and transfer ink from the other donor web bearing ink of the another selected color to the sheet material to print another color component of the image on the sheet material.
Dependencies are inferred from the claim text.