Image stitching for a multi-head printer

An apparatus for screening a region in a digital image, the apparatus comprising:

• means for dividing the region into a two-dimensional array of cells having n columns and m rows, wherein m≧2;
• means for selecting a first corresponding phase shift for each column in the array;
• and
• for each cell in the array:
• means for identifying the column containing the cell;
• means for identifying the first corresponding phase shift selected for the identified column;
• and
• first printing means for printing a dot centered at a location in the cell corresponding to the identified first corresponding phase shift.

A method for use in a multi-head printer to stitch a first and second region of a digital image, the method comprising steps of:

• (A) identifying a stitching region including adjoining portions of the first and second regions;
• (B) printing the adjoining portions of the first and second regions using both a first and second print head in the multi-head printer by performing steps of:
• (1) weighting the output of the first print head within the stitching region using a first weighting function;
• and
• (2) weighting the output of the second print head within the stitching region using a second weighting function;
• wherein neither the first weighting function nor the second weighting function is a step function.

An apparatus for use in a multi-head printer to stitch a first and second region of a digital image, the apparatus comprising:

• means for identifying a stitching region including adjoining portions of the first and second regions;
• means for printing the adjoining portions of the first and second regions using both a first and second print head in the multi-head printer, the means for printing comprising:
• means for weighting the output of the first print head within the stitching region using a first weighting function;
• and
• means for weighting the output of the second print head within the stitching region using a second weighting function;
• wherein neither the first weighting function nor the second weighting function is a step function.