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HP9000 banding issue

HIGHTEC

New Member
I'm looking for individuals that own HP 9000 printers. Or a techician out there that does regularly work on them. I'm a technician on the printers and I have an issue with one of them that I think I know the issue. This printer is printing horizonal line 6 to 12 in. in length to the right of the printer. Toward the wiping station, not the capping station. Via the 64 in. platen printing area. Standing in front of the printer looking 35 to 40 in. way from the capping station. There a small area to the right that is printing horizonal. I think it the encoder strip., one other technician stated it was the vibration of the carriage when it stop and coming back to the capping station, possible bad rollers. But the carriage seem tight and there visual damage. Or the encoder strip sensor is dirty. Possibly with lint or dirt. Anyone come across this, these are not vertical banding lines like a media feed issue or bad nozzle checks but a horizonal line coming at you if you are standing in front of the printer. I'm sure someone else out there has seen this and figured it out.

Hightec Digital
916-990-9803
 

tbaker

New Member
you have a picture you can show? this wouldn't be the weirdest thing I've seen these models exhibit, but it would come close.
 

drive

New Member
+1 for pix. i'm guessing it could be the encoder or carriage cables. my seiko 64s performed similar tricks recently. but pics would really help
 

MachServTech

New Member
I would recommend dis-assembly of the carriage and checking the carriage track for buildup which causes vibrations in a specific print area...like speed-bumps which can create pattens in the print. It can also be the bearing wheels on the carriage.
 

tbaker

New Member
I'm with machtech on this, the 9000/10000 are getting on in years, and lately I've seen a rash of printers with worn trolley plates caused by accumulation of crap on the upper rail. This typically presents itself as VERTICAL banding and is normally consistent across the platen, but, there's nothing to say that you couldn't have buildup in a couple areas on the rail leading to the pattern, I'd still like to see pics tho.
 

HIGHTEC

New Member
thanks

I will be going back to the printer toward the end of the week, I'm putting in new pump assembly for the capping station and the lower subtank pump assembly. I will take off the back cover and see what I can do, I ordered a new encoder strip, see if that helps. Keep you posted, and once fixed I will let you know what I did.

Thanks again, It greatly appreciated taking time out of your busy schedule......:U Rock:
 

sfd2122

New Member
Is it only in one color or multiple colors? We just recently had the same issue but only in magenta. It turned out to be the printhead. The tech had never seen anything like it. We found it by swaping the cables going to the top of the printhead. So we put the magenta cable to the cyan and the cyan to the magenta and the magenta head still had the horizontal line even though it was firing to cyan. We changed the printhead and it resolved it. Check the top of the printhead for the recommended factory voltage and then check in the maint. menu what the actual voltage is. HP only recommends a 2 volt difference and a lot of people go beyond that and it ends up decreasing the life of the printhead.
 

tbaker

New Member
Horizontal ( along the platen) banding can be caused by multiple things, I'm guessing what you really meant was vertical banding ( 90 degrees to the platen). I've seen this on some of the older 9-10000s, and the ones that are production work horses. The only 2 things that I have found that cause the vertical banding are;

1) junk along the upper rail. Clean the accumulation with alcohol, clean the roller bearings on the trolley plate assembly.

2) trolley plate assembly going bad. If the grime is allowed to accumulate too heavily on the upper rail, the trolley plate assembly roller bearings can go bad, causing failure in this part. If that happens, you have to remove the entire carriage assembly and replace the trolley.

While it is possible for it to be the encoder strip, that is easy to check, there will be something on it, ink, dirt or oil, clean with diluted alcohol, unless it's ink, then you're basically hosed.
 

Rodan68

New Member
Did you ever figure this out? I seem to be having the same problem with a Seiko Colorpainter. There's about a 10" wide area that has "micro banding". I'm pretty sure it's not from a bad head because the rest of the print looks fine and it seems to happen with all the colors. My area is about 4-5" away from the capping station.
 

Quix

New Member
I agree with sfd2122. Once I had a similar problem caused by solvent inside the printhead's circuits (it got there accidentally while cleaning them). The banding was horizontal, and It changed it's position depending of the image printed. It got fixed after drying the printhead's top.
 

Quix

New Member
For "micro banding" you mean vertical blurry spots? In case you get an uneven vertical banding, it could be that the media is wrinkling lightly (if it wrinkles hard, you get ink stains due to the contact with the printhead). I believe the uneven distance form the media to the printhead causes the misplacing of the inkdrops. I've been having this problems recently: My workshop is very humid this time of the year)
 
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