| 摘要 |
<p>Inkjet-printed images (characters or graphics) have an image-quality asymmetry, correlated with the direction of pen scanning. The invention exploits this asymmetry to improve apparent overall quality by forcing the less-perfect side of each image element to become, and be hidden in, the element interior. To achieve this effect, part of each element is printed during pen scanning in one direction and part during scanning in an opposite direction. Neither scan prints the trailing edge -- that is, the edge the pen reaches last, when moving in a given direction. Instead each scan prints only the leading edge -- plus the interior or part of the interior, if the image is wide enough that its interior forms an analytically separate portion. If the image is wider still, it is subdivided so that one discrete interior portion is printed in the same scan with one of the lateral edges (the leading edge in one scan direction) and an additional discrete interior portion is printed in the same scan with the other lateral edge (the leading edge in the opposite scan direction). The widths of the "leading edge" and also of top and bottom edges are defined to optimize print quality by finding the best tradeoff between oppositely acting surface-tension effects: when very wide portions are printed all at once, creating a large pool of liquid ink, objectionable "runners" occur (which effect favors defining the "edges" as narrow); but when only very narrow portions are printed, edges objectionably reveal the pixel structure conspicuously (which favors defining the "edges" as wide). Overlap dots can be included in the portion or portions printed when scanning in either or both directions, to avoid narrow unprinted gaps in case of misalignment between scans in opposite directions. <IMAGE></p> |
