Epson Stylus Color C70, Service Manual

Page: 92 / 216

EPSON Stylus COLOR C70/C80 Revision A
Troubleshooting Overview 92
3.1.6.8 Dot Missing 3
This section describes the procedures for checking the following factors which can
cause instability in printing even though all nozzles are firing ink normally. Carry out
the steps in the order given.
1. Characters are not sharply defined.
2. Horizontal and vertical lines are not straight.
3. White stripes or colored stripes are easily visible after high-speed printing.
6 Let the printer stand for a
day (if time permits). After leaving the printer for a day, (In worst case, 3 to 4 days
are required.) check if the missing printing appears to be
returning to normal. If it does appear to be returning to
normal, use the cleaning function on the panel, and the CL3
cleaning function and initial ink charge flag reset function of
the adjustment program and check the progress. If it does
not appear to be returning to normal, proceed to step 7.
7 Replace the print head. —
Table 3-19. Dot Missing 2
Step Check Point Remedy
Table 3-20. Dot Missing 3
Step Check Point Remedy
1 Have any parts or units
relating to the carriage
guide shaft been
removed or replaced? Carry out PG adjustment. Refer to Chapter 5 for details. If
this does not apply, proceed to step 2.
2 Has a head ID been
recorded? If no head ID has been input, the TG value combination
will fortunately not result in a head hot error, but the
voltages an frequency correction data that are appropriate
for that head will not be stored on the main board, and so
the control carried out will not match the head's
performance and unstable printing may result. Refer to
Chapter 5 for details.
3 Has the head ben
replaced? If angle adjustment has not been carried out, it should be
carried out. Refer to Chapter 5 for details. If the head has
not been replaced, proceed to step 4.
4 Carry out Bi-D
adjustment. Refer to Chapter 5 for details.
5 Carry out PF
adjustment. Refer to Chapter 5 for details.
NOTE: PF adjustment is an effective adjustment function
for high-speed paper feeding. It is an adjustment
function for when the high-speed settings for
Economy mode printing when print quality is not a
problem and for Normal mode printing are carried
out using the printer driver. Accordingly, it is an
adjustment that cannot be expected to have an
effect on printing problems during high-quality
printing.
6 Do the uneven parts of
characters only appear
in a certain raster? Because it is possible that the printer has received a severe
shock in the case of a specified raster, check this with the
customer. If the carriage encoder receives a severe shock
and momentarily stops reading, it may cause a direct ink
firing timing fault even if it does not result in a fatal error,
and this can cause character distortion for a particular
raster.
If the printer has not received a severe shock and printing
can be carried out once more, the problem is not
reproduced again.