Head Shading; Outline - Intermec ColorCoder V4 Service Manual

6.4 Head Shading

6.4:A Outline
Intermec ColorCoder V4 – Service Manual Ed. 1
The printer has four BJ line heads of 4-inch wide with 1408 nozzles
for each head. Since the each BJ head has each characteristics in
ejecting (printing), uneven shade in vertical direction (vertical
streaks) may be noticeable, when printing photographs or high-
duty illustration on the printer. The head shading (herein after
referred to as "HS") is to improve image quality, that is, corrective
data comply with the characteristic of each BJ line head is already
stored in a printer driver so that the printer driver can correct the
output of the BJ line head in the printing operation and in the way,
eliminate the vertical streaks on the image.
Effective HS
The HS is effective to correct and improve the vertical streaks
(uneven shade) which the characteristic of each BJ line head causes
(Figure 6-4). But the HS has no effect to a couple of vertical streaks
which non-fired ink and misaligned ejection, on the contrary, it may
make them emphasized.
When making new HS data therefore remove all the non-fired ink
or misaligned ejection by the cleaning operation before making it.
(See Chapter 6.7 Image Troubleshooting)
Never print out the HS test chart until BJ head has warmed up to the
temperature in which the printer runs usually. Use the test chart in
accordance with the condition in which the printer runs usualy,
because the printer self-controls heads' temperature and ejection
pressure could change accordingly.
Vertical streaks (uneven shade)
Chapter 6 Troubleshooting
Improved image after HS
Figure 6-11
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