HP 2000CP 2500CP - Manual (Page 150)

6-8 Image Quality HP DesignJet CP Series Printers
One of the most common problems that affects the overall image quality is
‘Banding’.
Banding Problems
Banding is when you see repetitive horizontal bands within the printed
image (these may appear as light or dark bands).
Test pattern 2 is printed with four primary colors; black, cyan, magenta
and yellow. The three secondary colors printed are; red, blue and green
which are composed by mixing the primary colors as shown in the table
below:
Secondary Color Primary Color
Components
Red (R) Magenta (M) and Yellow (Y)
Blue (B) Magenta (M) and Cyan (C)
Green (G) Cyan (C) and (Y)
The main causes of banding are due to:
D Printheads.
D Media advance.
Banding Caused by Printhead Problems
If test pattern 2 has clear or dark horizontal bands in one or more of the
primary color columns, then several of the secondary color columns will also
have the same type of bands in the same position (but perhaps with less
intensity).
These bands are caused by two types of printhead nozzle failure; either
nozzles not printing, or nozzles misdirected. For further information on
printhead nozzle failures, refer to Test Pattern 3
' page 6-13.
In the following Example A, several nozzles in the magenta printhead are
not printing. There will be clear repetitive bands (perhaps white) in the
magenta column. Consequently, you will see lower intensity bands in the
same print position in the red (M + Y) and blue (M + C) secondary color
columns.