| 摘要 |
A method of preparing a two-dimensional bit-mapped image is disclosed in which the image has n pixels per row for printing using one or more printheads each having a row of ejection locations. Each ejection location has associated ejection electrodes to which a voltage is applied sufficient to cause particulate agglomerations to be formed from within a body of printing fluid. In order to cause charged particulate agglomerations to be ejected as printed droplets from selected ejection locations, voltage pulses of predetermined amplitude and duration, as determined by the respective bit values P i , where 1 ‰¤ i ‰¤ n, of the individual pixels of rows of the image, are applied to the electrodes of the selected ejection locations. P i is determined by the expression: FOR i = 1 to n :
FOR j = 1 to (4 k +1):
IF P i ‰¤ P L AND P i +1 ... P i+(1+k) ‰¤ P H then P i+j = ± j .P i+j
or
IF Pi ‰¤ P L AN D P i -1 ... P i -(1 + k ) ‰¥ P H then P i-j = ± j .P i-j
where ± j < 1 for j = 1 or j = 2 k and ± j ‰¤ 1 for j = 3 k or j = 4 k
OR
FOR i = 1 to n:
FOR j = 1 to (4 k +1):
IF P i ‰¤ P L AND P i +1 ... P i+(1+k) ‰¥ P H then P i+j = ± j .P i+j
or
IF P i ‰¤ P L AN D P i -1 ... P i -(1+ k ) ‰¥ P H then P i-j = ± j .P i-j
where ± j > 1 for k ‰¥ 2 and ( j = k or k +1), and ± j ‰¥ 1 for k ‰¥ 3 and
(2 ‰¥ j ‰¥ k -1 or k +2 ‰¤ j ‰¤ 2 k -1 or j = 2 k +1, 3k+1, or 4 k +1),
where P L is a low threshold and P H is a high threshold defined as 0 < P L < P H < 1, and where the arrangement of the printheads forms an array of ejector locations on a spacing parallel to the rows of the image of k times the pixel spacing of the image arranged parallel to the width of the image, with A interleaved printheads arranged to print on B interleaved passes, such that k = A.B such that a given printhead on a given pass will print the pixels of every kth column of the image. |
