Dot Size; Too Much Ink; Dot Depletion; Print Quality - HP DesignJet 200 Service Manual

Dot Size

Each dot produced by a 300 dpi cartridge has a diameter of 0.0055 in. The dot size must be
larger than 1/300th of an inch (0.0033 in.) so that when a single dot wide line is printed, dots
overlap and the line appears to be continuous.

Too Much Ink

A 600 dpi grid contains four times as many dots as a 300 dpi grid. This means that four
times as much ink can be laid down on a 600 dpi grid. Media cannot absorb that much ink
effectively; it puddles, runs, and dries slowly.
To solve the ink problem, sophisticated algorithms produce asymmetrical dot

Dot Depletion

arrangements to selectively reduce (deplete) the number of dots placed on the addressable
600 dpi grid in enhanced mode. (The same happens on the 300 dpi grid in draft mode, but to
increase plotting speed.) Dot size is not varied in any of the print modes.

Print Quality

is fast and uses half the ink of true 300 dpi resolution. Special algorithms control

Draft mode

dot placement, creating a virtual 300 dpi image, rather than skipping every other dot. The
image appears considerably lighter than the true 300 dpi print quality.
uses true 300 dpi resolution. Plotters set to plot on a 300x300 dpi grid directly

Final mode

map 90,000 raster image dots per square inch to 90,000 drops of ink.
(on the DesignJet 220) uses addressable 600 dpi resolution. This involves

Enhanced mode

300 dpi cartridges on a 600x600 dpi grid. Dot depletion results in the same amount of drops
used as in true 300 dpi mode. Print quality improves because the dot centers may be located
anywhere on the 600 dpi grid. This results in smoother curves, straighter low angle lines,
smooth edged area fills and easily readable small text.
5 14 Functional Overview
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