Epson P20000 Vertical Banding (Or misalignment?)

[aaronchan]

Dear all,

I just purchased a P20000 less than 2 months ago. But seems like I've got some werid problem with this printer which I had never had on my other Epsons.

If you look at the image, my corner mark wasn't printed properly, it has a double line instead of single. The this is a vertical line. One thing I have to mention is it happens greater toward to the end of a roll paper, also, the difference between both sides and center is a bit different.

This is a Hahnemuhle Photo Rag 308 with OEM inks.

I was trying to do the printhead alignment, after it prints out lots of vertical lines and patches across the width, I've realized there are some difference arocss the width. For example, VLM1 looks good at 7 in the first one from the left, but the one from the right is 6.

Anyone has this kind of problem with the P10k/20k before?

Thanks
Aaron

[JRSmit]

Is your head-alignment ok?
That is the first thing i would check.
Note that my experience on the SCP20000 is  that the manual headalignment will give far better results than the auto.

Dear all,

I just purchased a P20000 less than 2 months ago. But seems like I've got some werid problem with this printer which I had never had on my other Epsons.

If you look at the image, my corner mark wasn't printed properly, it has a double line instead of single. The this is a vertical line. One thing I have to mention is it happens greater toward to the end of a roll paper, also, the difference between both sides and center is a bit different.

This is a Hahnemuhle Photo Rag 308 with OEM inks.

I was trying to do the printhead alignment, after it prints out lots of vertical lines and patches across the width, I've realized there are some difference arocss the width. For example, VLM1 looks good at 7 in the first one from the left, but the one from the right is 6.

Anyone has this kind of problem with the P10k/20k before?

Thanks
Aaron

[ssgphoto]

What does the image area look like? Is the misalignment only in the corner marks or throughout the image area?
What media type do you use for HPR308?

[aaronchan]

Is your head-alignment ok?
That is the first thing i would check.
Note that my experience on the SCP20000 is  that the manual headalignment will give far better results than the auto.

Seems like I have solve the problem by doing the manual head alignment.
Hopefully it won't happen again because this is a brand new machine....

thanks
aaron

[cunningIMG]

I also had this issue soon after purchasing my P20000 in January 2018. Manual head alignments fixed the issue but it was not resolved for too long before I noticed the alignment off again. I had Epson service tell me that multiple auto alignments create a better alignment(they said 3 was good) as they "build" on each other.
I still perform manual head alignments on the machine to get the best results.

What software are you using to print Aaron? I have also noticed different results with different softwares/RIPs —which is something I can not explain.

[Stephen G]

Assuming your paper settings are correct, it could be caused by paper curl. When curl is too strong (end of roll situation with some papers) then the suction bed is not able to hold the paper flat enough. The paper lifts up slightly, effectively making the platen gap smaller. The head to paper surface distance is now wrong so you get the double lines.

Here's my thinking as to why this is the case: I think of platen gap as focus. If the head is too close to or too far away from the paper surface then you get defocus. Slight errors in platen gap distance are almost undetectable. Bigger errors start showing up as slightly unsharp prints, at the very fine detail level. Larger errors than this and you see clear double imaging.

I'm basing this on 9yrs combined experience with a 9900 and a P9000.

Test: run a print with those crop marks near the end of a roll. If you get the double lines cancel the print. Print it again, but this time spool out about 5cm of paper before you start the print. This gives the suction bed more paper to work on and it is more effective at keeping the paper flat, i.e. keeping the paper surface at the correct distance from the head.

My prediction is that the double lines will go away. If they do not then look at your paper settings. With a smooth predictable paper like Photorag I would use the recommended VFA setting, with platen gap left on auto. Paper thickness must be set correctly too, but I think VFA is a close match for Photorag308 so you won't need to change it from the default 0.5mm.