Gray tone generation
AssigneeTeletype Corporation
InventorsJames M. Berry, Anthony J. Hauser, Kurt E. Knuth, Gary B. Ollendick
Life of this patent
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Abstract
An ink jet printer in which refined half-tones or shades of gray are produced while retaining high contrast capability using a dot matrix in which the dots are of the same density for the same shading plus or minus one drop of ink at selected dot locations within the matrix but with each dot being printed in response to an individual shading density or darkness input signal.
Claims11
A method of refining a gray shade image produced with a liquid ink-jet recorder that projects discrete drops of ink onto a record divided into matrix cells, each matrix cell including a plurality of dot locations;
- depositing enough drops of liquid ink at each dot location of a matrix cell to produce approximately the requisite shade for that dot location within the matrix cell;
- and
- selectively adjusting the number of drops deposited at a dot location of the matrix cell area to refine the approximation to a more accurate half-tone representation of the image.
In an ink jet device for recording dots on a record, apparatus for forming images having shades of gray, comprising:
- means for causing the recording device to deposit at a predetermined dot location in a matrix cell on the record a number of drops of ink substantially representative of the shade to be recorded at the matrix cell location;
- and
- means responsive to the location of the predetermined dot within the matrix cell for selectively adjusting, by one, the number of drops of ink deposited at the predetermined dot location so as to refine the density of the image recorded on the record.
An ink jet device for recording dots on a record, including apparatus for matrix-forming images having shades of gray, comprising:
- means for depositing at each dot location of a matrix of dot locations a number of drops of ink to produce a shading no lighter than the shading of that dot location within its associated matrix cell;
- and
- means for selectively depositing an additional drop of ink at selected matrix cell dot locations to darken the cell no more than the darkness produced by an additional drop of ink at all dot locations of the cell.
Dependencies are inferred from the claim text.