HP 750 - Manual (Page 194)

750C
750C
Plus
755
CM
9-16 Print Quality C4705-90000
Pattern 3 (on the CAD color diagnostic pot) contains vertical and horizontal lines ofthe four
basic colors (cyan, magenta, yellow and black). This is a worst case situation, which provides
qualitative information.
Pattern 4 (on the CAD color diagnostic pot) includes one square and horizontal and vertical
lines in red (yellow plus magenta), blue (cyan plus magenta), and green (yellow plus cyan). The
horizontal and vertical lines can be used to verify whether the alignment between the
cartridges used to print them is within the required specification. The lines are one pixel in
thickness. If the plot is printed on matte film" media the dot size is approximately 3.33 mils
diameter (the same value as the alignment specification). Focus on one horizontal or vertical
blue line (see figure below), that is generated by two lines of cyan and magenta. If there is a
misalignment between the two cartridges, bigger than 3.33 mils, the lines will be this distance
apart. In this case, there will be a white line between the magenta and the cyan, as the dots of
each color will not come in contact. (The distance will be bigger than the dot size.) When there
is a blue line between the magenta and the cyan, then the distance between the lines is smaller
than 3.33 mils, hence, the alignment error is within the required specifications.
Dot size 3.33 mils
(Film / Glossy)
Alignment error
3.33 mils
In Spec (limit)
Alignment error
< 3.33 mils
Out of Spec
Corrective Actions
Ifthe penĆtoĆpen alignment error is out ofspecification:
D Perform the pen alignment test using white media ' page 8Ć40.
D Perform the lineĆsensor calibration (details ' page 7Ć5) and perform the pen alignment
test again.
D Replace all cartridges.
D Replace the carriage ' page 6Ć34.
D Troubleshoot the EEROM and the Main PCA.