Fb 700 Banding Help

[Jboogie214]

Our FB700 is creating strange "vertical banding" that runs the direction of the media path and not in the typical direction of the printhead. This banding seems to be more of a streaky halo effect and is not perfectly uniform the entire length. We have had our tech out to solve the problem but so far no luck. He has done all the cleaning, calibration, belt tensioning, etc. that he can think of but nothing is solving the problem.

The issue definitely shows up worse in dark or solid color areas. Also, the problem is either exaggerated or diminished by the media we are printing on. i.e.. Expanded PVC (Sintra, et al) is worse than styrene for some reason. The streak pattern is still visible on both medias though, and does seem to align from one board to the next.

Does anyone else have this issue and is there a solution or work around? Please help!

Attached are two photos showing the vertical banding issue (again the bands are not running in the same direction that the printhead was printing, they are running in the same direction as the table media belt)

Thanks...


Full Color banners seem to be the worst.

 

[FrankW]

Vertical Banding on that machines could have a lot of reasons, mechanical and others. There could be dirt on carriage wheels, carriage rail or linear encoder, damages or wrong calibration of carriage motor or carriage drive belt, problems with the lamp shutters and much more. There is a technical document available from HP for authorized technicians with 24 pages about reasons of vertical banding.

Is that banding over the whole width of the media? Or just on parts of the width? With which print mode that bading appears?

If cleaning wont help, perhaps you need some new parts.

But: vertical banding is not completely avoidable on every media in every print mode on machines like this. A wide, heavy carriage will not move 100% perfectly along the rail. And it is not only on HP-Printers: a few weeks ago, I have visited a customer while a technician desparately tries to find reasons for vertical banding on a relatively new Océ.

But, of course: if you have printed with this printer a long time and that symptoms are new, your machine needs repair.

 

[Jboogie214]

The banding typically happens on either indoor signage plus our outdoor signage plus. Depending on the substrate it can barely be seen or its visible quite clearly.

Vertical Banding on that machines could have a lot of reasons, mechanical and others. There could be dirt on carriage wheels, carriage rail or linear encoder, damages or wrong calibration of carriage motor or carriage drive belt, problems with the lamp shutters and much more. There is a technical document available from HP for authorized technicians with 24 pages about reasons of vertical banding.

Is that banding over the whole width of the media? Or just on parts of the width? With which print mode that bading appears?

If cleaning wont help, perhaps you need some new parts.

But: vertical banding is not completely avoidable on every media in every print mode on machines like this. A wide, heavy carriage will not move 100% perfectly along the rail. And it is not only on HP-Printers: a few weeks ago, I have visited a customer while a technician desparately tries to find reasons for vertical banding on a relatively new Océ.

But, of course: if you have printed with this printer a long time and that symptoms are new, your machine needs repair.

 

[HulkSmash]

Could be a heat or statics issue. Could very likely be the substrate as well. Try Higher passes.

 

[Jboogie214]

Im not well informed on how to in regards to passes. I will be changing the lamps here shortly. Thanks for your help.

Could be a heat or statics issue. Could very likely be the substrate as well. Try Higher passes.

 

[fozzie]

Are you running 6 color mode or 4 color mode. We had similar issues running 4 color. Switch to 6 color (same media) didn't do it.

 

[Jboogie214]

We are running 6 colors.

Are you running 6 color mode or 4 color mode. We had similar issues running 4 color. Switch to 6 color (same media) didn't do it.

 

[FrankW]

Im not well informed on how to in regards to passes. I will be changing the lamps here shortly. Thanks for your help.

You can't select Passes on the FB, you need to select a higher print mode.

About heat: how old are the lamps? You know that when they reduce UV-power, you could switch them from low to high power to compensate that reduction for another few hundred hours? Heat problem could also be a problem of filthy air filters on the lamp housings.

 

[fozzie]

Vertical Banding on that machines could have a lot of reasons, mechanical and others. There could be dirt on carriage wheels, carriage rail or linear encoder, damages or wrong calibration of carriage motor or carriage drive belt, problems with the lamp shutters and much more. There is a technical document available from HP for authorized technicians with 24 pages about reasons of vertical banding.

Is that banding over the whole width of the media? Or just on parts of the width? With which print mode that bading appears?

If cleaning wont help, perhaps you need some new parts.

But: vertical banding is not completely avoidable on every media in every print mode on machines like this. A wide, heavy carriage will not move 100% perfectly along the rail. And it is not only on HP-Printers: a few weeks ago, I have visited a customer while a technician desparately tries to find reasons for vertical banding on a relatively new Océ.

But, of course: if you have printed with this printer a long time and that symptoms are new, your machine needs repair.

have had a long time HP tech the last 2 days here working on our fb950. everything above is true and he helped elaborate some. basically, as the carriage moves back and forth it is never completely straight - many issues, i.e., mechanical, dirt, wear, etc, contribute to it. so instead of a straight line, you get a sine curve back and forth. cyan and magenta are the worst for this, so blues and purples show it the worst. when you go bidirectional the sine curves are intersecting and will produce the vertical lines more. he recommended going uni-directional to help minimize this. different medias show it more also.
not an HP thing, all printers to a degree have this.
hope this helps. so try uni-directional.

 

[Hotspur]

Maintenance!

Hi
Hopefully simple one I've seen multiple times (I've sold over 100 of these)
The head runs on wheels in a metal track.
When tiny pieces of dirt get stuck in the rail / wheel the head "jumps" a tiny amount as it runs over it causing a slight difference in the print in the same places.
When the media passes underneath the same spot a vertical band is created.
Have another look in the maintenance guide and specifically at the rail cleaning.
It can be very tiny pieces almost invisible and sometimes hard to shift so an initial cleaning doesn't always get it - but take some time and look v carefully and make sure that aluminum bar is spotless and the issue should go away.