Oce Arizona 640 GT, User Manual, Page: 176 / 230

How To Improve Quality When Banding Occurs
Introduction
Banding can occur in an image for a number of reasons. Typically it occurs due to neighboring
nozzles that do not fire or multiple nozzles that fire with poor directionality. This can occur if the
printer sits idle for an extended period of time (e.g., overnight or longer), or if debris has been
picked up from the media or table by a printhead. If this happens, perform the Printhead
Maintenance procedure to clear the affected printheads. If banding is evident, print a nozzle check
to identify which nozzles of a particular print head are not firing. After you perform the printhead
maintenance, print another nozzle check to confirm whether the problem has been fixed.
If a print shows banding and a nozzle check print shows more than three separate nozzles out or
two or more adjacent nozzles out, the following procedures for recovering clogged nozzles is
recommended to improve image quality.
NOTE
Keep the table surface clean and ensure the media is clean and free of dust to help reduce
banding. Use an anti-static brush, if necessary. Also use a micrometer to accurately measure the
media thickness so the proper printhead gap between the printhead and the media is used. If the
printhead gap is less than it should be, there is a greater probability of picking up debris on the
printheads
Recovering Clogged Nozzles
When banding appears in an image and nozzle dropouts appear in the Nozzle Check print, we
recommend that printhead maintenance is performed. In some cases it may be beneficial to print
an image file after maintenance, to exercise the firing of the nozzles, then run the Nozzle Check
again.
If some nozzles are still out, perform a purge of only the printheads with nozzles out. To do this,
close the ink valves of the colors that don't require a purge, then purge to remove excess inks.
If dropouts still persist, you can also swab the printheads.
How To Improve Quality When Banding Occurs
176 Chapter 11 - Error Handling and Troubleshooting
Océ Arizona 600 Series