HP Scitex FB950 Printer series - Manual (Page 117)

Wide horizontal banding, sometimes referred to as “directional gloss banding” or “lawnmower banding,”
which may be caused by light reflecting differently off adjacent printed areas. Ink that is laid down when
the printhead carriage is moving in one direction will have a different reflectance characteristic than ink
laid down in the opposite direction. This effect varies with the viewing angle, and is more pronounced
in darker images with higher ink saturation. To reduce or eliminate gloss banding, try these measures:
1. Use Plus mode — a special print mode designed to reduce the banding effect. Prints at a slightly
reduced speed relative to printing without Plus mode.
2. Use a reduced gamut color profile — these color profiles restrict the gamut used, which reduces
the color saturation in the printed image. If available, they can be downloaded from the RIP
manufacturer's web site (see
Choose a color profile on page 109 ).
3. Print with 4 colors instead of 6 to reduce the ink load and saturation.
4. Print in a higher quality mode — do not use Billboard mode; if printing in Production mode, try High
Quality mode instead. This will reduce the print speed, which will reduce the visible difference
between adjacent bands.
5. Print unidirectionally — this eliminates adjacent bands printed in opposite directions, but reduces
throughput by 50 percent, since the printer is printing in one direction instead of both directions.
6. Laminate — applying an overlaminate to the print will reduce the banding effect and provide extra
protection against damage.
Thin banding
Thin horizontal banding or stripes may indicate clogged inkjets or miscalibrated media feed.
●
If you see a white (missing color) line in only some colors, check jet health using the procedure at
the beginning of this guide.
● If a white (missing) or dark line appears across the entire width of the print, check media feed
calibration from the printer's control panel (Menu > Manual Calibrations > Media Feed Calibration).
● If used, Plus mode could have the effect of producing thin horizontal banding that resembles a
media feed error. In this case, try printing without Plus mode.
● Having a shuttered trailing lamp (as with the gloss-enhancing configurations) in any print mode,
but especially in a fast Plus mode, can also emphasize a thin dark line in some colors at the print
swath boundary. In this case, try changing the shutter setting.
ENWW Troubleshoot image quality problems 111