HP L25500 Random Out Of Alignment

[VFT]

Hey all,

I'm having a problem that I just can't seem to figure out. It randomly goes out of alignment and then prints fine. I have cleaned and oiled the carriage rails, cleaned the encoder strip, checked the belt and the gear drive for debris, ran a vacuum check, realigned the print heads and a few various other things and I just can't get it to stop. It's never in the same place and it doesn't matter if it's the first print, somewhere in the middle or at the end. I really need to get this fixed. These prints are unusable like this. I was thinking it might be a feed issue, but I don't know where to start with that. I've attached a few pics to reference, but sometimes the offset is narrower than these examples. Anyone have any suggestions?

 

[BIG EASY DOES IT]

I had a similar thread going on reflective materials. What's the backer for your vinyl made out of. Is it super smooth. I believe our issues come from some sort of slipping on the pinch rollers. We've also thought it might be due to adhesive build up on the platen under the heater section. Our printer is also a L360 model. We have a L365 model that doesn't display these issues. What we have done is clean as much residue/adhesive from the platen area as possible and now use the take up real from beginning to end every time. Every once in awhile we have an issue still and I think it's while the take up real engages and it moves the print at the same time. We have also tried everything in the book to correct printing issues. I will also say we don't have this issue on any of the vinyls we use, but i think it has more to do with the backer of the materials then the face of the material. Just my 2 cents as we have not found a confirmed answer for this.

 

[VFT]

Thank you for your suggestion. I did also clean the entire platen area and checked the rollers for debris. None was found. I can clean it again just to make sure I didn't miss anything. I can also try using the take up reel. This printer is new to me so my media selection is limited. I was running Oracal 3640. The only other media I have in stock is Forward Banner 13 oz and UltraFlex Strip Mesh LTX. I've ran 10 of these and so far only 2 are any good.

 

[ddarlak]

This is purely my opinion so take it with a grain of salt and I'm going to make some assumptions here...

I assume you bought a used l25500? This was the first Latex printer HP made, it's roughly 6 years old and it was designed to last about 3.5 years. It is nothing more than a fancy large desktop printer designed to sell ink. It really can't be trusted once it passes 3 years or 100K Sq Ft.

Yes there is a solution to your problem, No I can't fathom what it is. It really doesn't matter what the problem is, there will be another one and then another one down the road.

I have owned 4 of these units, I have printed probably 200k sq ft through them. When they are done, they are done... They eat your time and become boat anchors real quick.

 

[VFT]

I appreciate your opinion and understand that I purchased an old machine. I have had many different machines run long past their "expected lifetime". I have also had many different techs tell me that I need a new head or cable or motherboard, or my machine is completely shot etc when in reality the fix was as simple as a loose screw, a dirty sensor or my personal favorite was a small piece of fuzz. Now, I'm not saying that this is always the case, but it seems to me the manufacturers never seem to know all of the quirks of their own equipment, but if you take the time to learn them yourself, there is almost always a solution. It all boils down to how much time are you willing to spend and what's it worth to you. Personally, I don't have the time, but I have a client that was promised a product by Monday and I intend to produce said product.

 

[VFT]

I have tried the take up reel suggestion and it's still doing it. I would guess that it is a feed issue of sorts, but I'm not exactly sure where. I even disabled OMAS to see if that had something to do with it. I'm printing 2 across on a 50" roll and both images are coming off identical so I figured it was pretty safe to rule out a vacuum issue. Any one else have any other suggestions?

 

[Bly]

It looks like an encoder strip issue. Pretty sure the encoder strip on those can't be cleaned and they recommend replacement.

 

[dale911]

There is regular maintenance of the encoder strip mentioned in the service manual so there could be some possibility to that. I emailed your info to another tech friend and I’m awaiting his response.

I don’t think it’s encoder because it’s not consistently doing it. I assume that the first image you sent shows the text printed horizontally across the platter. That being the case, for some reason, you for are getting a feed problem. Was this hooked up to the takeup reel when you were printing this? Also, the platter may be clean but the pinch rollers is where it matters. They are not super easy to deal with by qtips and isopropyl alcohol will take off ink and other dirt from them. If you haven’t already, print this without the takeup reel and see what happens.


Sent from my iPhone using Tapatalk

 

[VFT]

Thanks Dale and I agree with you. The encoder strip run the X-axis of the printer and the left to right alignment is perfect. To me, this looks like a Y-axis problem. I have tried with and without the take up reel. It's inconsistent. I can watch the entire thing print and not hear a single noise or anything that might indicate that it's going to screw up. I can look at the platen some more and see if I can find anything that's causing it to over/under feed the material. I'll break out the Q-tips and alcohol and give that a shot. I thought maybe there was a problem with the spindle itself, like maybe there was a broken tooth etc. and that was causing the slip, but the distance between each screw up varies. One slip is 15" away from the one before and the next is 9" and so on. I'm usually pretty decent at trouble shooting, but this thing has me completely stumped.

 

[VFT]

Well, every roller is officially as white as the Cheshire cats smile and the issue still isn't resolved.

 

[VFT]

After some more testing there is a pattern. I just couldn't see it in the other file with the yellow background. It appears that the halo or whatever you want to call it appears every 8-9". Does that ring a bell with anybody?

 

[henryp]

After some more testing there is a pattern. I just couldn't see it in the other file with the yellow background. It appears that the halo or whatever you want to call it appears every 8-9". Does that ring a bell with anybody?

Not familiar with this printer model but that is possibly a PF Encoder issue

 

[VFT]

I just wanted to say thank you to everyone that commented. I really appreciate the help and advice. It was the encoder disk.