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NovaJet 500/630/700 Series Service Manual
MAINTENANCE
Maintenance 3-17
7. A flow restriction in the ink delivery system or ink starvation
in the cartridge. Ink starvation in the cartridge can be caused
by a broken valve in a quick release fitting or pinched tube in
the ink supply lines of the tubing/chain assembly. Check the
ink delivery system for any flow restrictions by disconnecting
the ink cartridge needle from the cartridge in question, raise
the tip of the needle and observe the rate that the ink flows
back into the reservoir. The ink should take approximately 1
inch per second to clear the 3.5 inch cartridge tubing between
the cartridge and the first quick release fitting (flowing back
toward the reservoir), if it takes longer than this, you may
need to replace a defective quick release fitting (near the
cartridge or the reservoir) or tubing/chain assembly.
8. Wiping during a print can sometimes cause a band of lighter
density color in the image. Auto wipe may need to be
temporarily turned off to prevent banding.
9. Operator intervention. If someone lifts up the media on the
take-up side of the printer while it is printing, it can cause
momentary banding in the print. Lifting up the media while
printing changes the inkjet head-to-media distance and will
effect the printed dot size and placement of the ink droplets.
10. Cartridge failures can cause banding — electrical cartridge
failures and partial clogging of the inkjets can produce
banding. With Inkjet Detection and Compensation
technology, electrical cartridge failures and clogging can be
corrected for up to 20 failures per cartridge with minimal
degradation of the output.
11. Media width variations causing the media to drag on the
media guides can cause banding. Check the edges of the
media for evidence of media drag and edge anomalies.
12. Lower quality dithering. Select the highest quality dithering
pattern in the printer driver. i.e. stochastic dithering.
13. Deadband and cartridge calibrations. If the deadband
calibration is off, or the cartridge calibration is off, it can
effect banding. Also, if one color seems to be causing the
banding — shifting the color calibration of that color +/-1 unit
may help.