Hp 26500 vertical banding

[Kwiksigns]

Soo... This happens on every print. Vertical bands inline with rollers. Prints like that. Blues show up on one side and the reds show up to the right. Low resolution or high res, doesn't matter. I've used flexi and onyx. Both do it. HP keeps telling me I have to print at the highest resolution for everything... This defeats the purpose of buying this printer. It shows up terrible in green and blue. I don't know what the f is causing it...

 

[dypinc]

Looks like not best media, uneven coating. Shows up because of to much ink laydown for the amount of passes or drying heat and air flow not high enough for amount of pass for the quality of the media.

 

[Kwiksigns]

forgot to mention... happens on every media I have tried... RS, oracal trans, elcheapo, banners...

 

[gregwallace]

You say the vertical bands are inline with the rollers? Are you referring to pinch rollers?

 

[Snydo]

forgot to mention... happens on every media I have tried... RS, oracal trans, elcheapo, banners...

Have you tried turning your temps way down to see if the banding goes away....I have experience with an L25500 and my first guess is way too much heat. I run Oracal 3641G all the time and if I need to plot the job I use the HP Lowtemp Photopaper profile which is 18-pass uni-directional, if I were to use the Oracal profile my plots would be 1/8" off(in the middle of the print). My point is that the printer is likely warping the hell out of your vinyl. Low and Slow for best results on the L25500 anyway.

 

[chafro]

Hi,

How many passes are you using? Your are or laying to much ink or printing on way to low pass for that media.

Also,, print in onyx the ink limit file,, the bigger the better. Most original profiles lay to much unesessary ink.

 

[ExecuPrintGS]

You say the vertical bands are inline with the rollers? Are you referring to pinch rollers?

This is the first thing I'd check... Looks like roller lines to me... We get that on our Roland all the time, on our new jv130 I've adjusted the roller pressure to light on the center rollers and heavy on the outside edges where the printer won't print

 

[Kwiksigns]

No warping of media. I know it looks as if too much ink is in the one spot, but the pics suck. The line in the more red colors actually has a lighter line. I might try the roller pressure idea because they are right in the middle... But only happens in certain colors. Actually, its always there just more or less. I tried a Hp profile with Hp vinyl cause Hp said my settings were all correct except the media, so I switched and no better. If it were too much ink, it makes no sense as to why its only an inch wide in the middle of the print. You see it immediately as the first pass starts. Hp is pissing me off more and more. They said replace the heads cause they are out of warranty then he will replace stuff, but the head test showed they are perfect even though they have passed a lot of ink and are out of warranty. I don't think that is the issue but I will try it.

 

[Kwiksigns]

My problem with this whole thing is that Hp says "you need to print at the highest passes for everyhing"... If we had known this to begin with, I would have NEVER gotten this thing as the production speed is way too low and, if that's the case, falsely advertised.

 

[chafro]

Not the highest,, around 8-10 pass for most media. I like to use 12 pass for best quality and make the heads last longer.

12-16 pass for backlights and fabrics, sometimes 20 pass when very saturated reds, blacks, blues or greens.

i think speeds are very descent for a 15-20k printer, good ROI if you have the work.

The fastest speeds that ALL company's advertise never give you usable quality prints. All the industry does that. Always need to make some test prints to see at what speed is the quality good enought for your kind of work.

 

[danno]

We have had our L26500 for about 1.5 years. Have found that we must do test prints at different passes or particular colours. Most stuff runs at 10 pass. Greys and greens usually at 12 pass with a heat reduction. We did have some profile issues, where the machine didn't cooperate with the profile. Since then, we have switched back to the stock profiles, HP media, for all our prints and modify passes as needed. If we can't hit the colour we want, then we switch to one of the 9000's we have in the shop.

 

[Turtle]

I had a similar issue with my 26500 when it was new. The problem turned out to be a defective encoder strip. I had stripes (vertical bands) running full length through my prints. It's a good reason to have a service contract although my fix was covered under warranty.

 

[Kwiksigns]

SOOO.... HP sent out a whole replacement kit for the rollers. But... while we were replacing it, we noticed on the encoder strip, there were scratches. These scratches are exactly where we would have an inch vertical band. EVERY ONE. This thing took him 5 HOURS TO REPLACE, and then Frank, technician, sees the strip and goes, "oh... that part only takes about 30 minutes to replace"... go figure. that was about 2 hourts into taking apart the printer so that was at the point of no return. I don't even know when they plan on shipping a new one or if he told HP, but I have 3 or 4 wraps to print for this week and next so... yeah...

encoder strip is 99% the culprit.