If you have an ImageWriter LQ, you may get a strange test print of
varying print density which is caused by an incorrectly installed black
print ribbon.
If you get a test print with a black ribbon that shows four lines of light
print followed by three lines of dark print, the pattern continuing as
long as the test print is generated (the ribbon may also move vertically),
here is the reason for the problem -- and the solution.
The black ribbon has a small tab on the left-hand end which actuates a
micro-switch located in the left-front of the printer near the control
panel. This indicates to the printer that it does not have a color ribbon
installed (the color ribbon does not have this tab.)
When a COLOR ribbon is installed the micro-switch is not depressed, which
sets in motion the various color functions of the printer, such as ribbon
vertical motion, overstrike for certain colors, etc.
When the BLACK ribbon is installed, the micro-switch should be depressed,
setting the printer into single-color mode.
The characteristics of a color test print are such that four lines are
printed in single colors and three lines are generated with overlaid
colors. With a color ribbon installed this will result in a color sequence
as follows:
- Black, Yellow, Red, Blue, Orange, Green, Purple (the last three are the
overlaid colors.)
However, if the black ribbon is installed but the micro-switch is NOT
depressed, the printer believes it is in color mode and will generate a
test print accordingly. This will result in four lines of light print
(printer thinks it is printing single colors and does a single pass with
the print head) and three lines of dark print (printer thinks it is
printing overlaid colors and does a double pass with the print head,
moving the ribbon vertically as needed to access the second color.)
If you have this problem, make sure the black ribbon is correctly
installed in the printer. Correct installation will depress the
micro-switch and set the printer in single color mode, which will
generate a test print of uniform density.