HP LX850 Black fade on Polyester

[sballinger]

We've had our LX850 since last August and we primarily print Fisher Textiles GF4417 Soft Knit. Just printed a 33ft banner with a lot of black. Noticed about 3/4 through the black got lighter for about a foot and then back to normal again. This isn't the first time this has happened. HP can't explain it, I've learned their tech service is useless over the past year.

Any thoughts? Overheated printhead, ink delivery problem, PH?

 

[WYLDGFI]

What mode are you printing in???

 

[sballinger]

We print our fabric at 250% ink density, 18 pass uni, you can't get any higher on the LX850. We found this to be the best way to get dense blacks...to bad it decides to flake out. I should note it's horizontally faded, so it's in the path of the printheads

 

[Jack Knight1979]

sounds like ink fade. are you getting this on anything else? Black head losing prime? Can you increase the ink output or try another profile?

Are you able to decrease the carriage speed? This will help keep a steady flow of ink through the heads.

We print our fabric at 250% ink density, 18 pass uni, you can't get any higher on the LX850. We found this to be the best way to get dense blacks...to bad it decides to flake out. I should note it's horizontally faded, so it's in the path of the printheads

 

[sballinger]

I thought it might be the black head losing pressure, checked the head and connects, made sure the o-rings that fit into the top of the head were lubed and not dry. Looks good, I've even tried a second head that we have in stock, same thing.

When I colored calibrated the fabric, the ink restrictions ended up maxed at 100% for all six colors. It's pumping out the ink.

My understanding from HP is that if the printhead is experiencing overheating, it will slow the carriage to compensate and allow it to cool down.

I've even had our Techs from Northlight Color look at the problem and they can't explain it.

I'm going to try and print the file again and see if I get lucky....this LX850 can be a little bi-polar at times!

 

[Jack Knight1979]

NLC are a good group of folks.

Slow the head carriage if you can. It needs a little more than what the firmware is allowing for travel.

 

[sballinger]

NLC has been great for us. They had techs out here for days fixing a ink delivery problem and cyan ink spraying incident right after install. Mike Lynch is my go to guy!

I'll see if their is a way to slow that carriage down, thanks

 

[sballinger]

Ok, contacted HP, tech told me the 850 has a hard time producing solid colors on fabric (wish someone would have told us this before we dropped the $200k on the printer)

Regardless, no way to slow the carriage so I tried everything the tech and I could think of, I also have the service manual that the field technicians use on our computer, so after everything it looked like it was better and then back to square one. I've added some photos to show the problem. I'm out of options