I have a R2880 that I use for PiezoDN. Printed a negative the other day that had banding so I did a couple head cleanings and a nozzle check. Everything looked OK except for the (yellow) K7 channel. I could not see any lines so tried a couple more had cleanings. Same result.
Then I pulled all the cartridges and did a flush of that channel with PiezoFlush, as well as cleaned the capping station, etc and did a scrub of the heads. Same result nothing through the yellow channel. Since I had a new spare cartridge I filled it up and replaced it Still same, nothing is showing through the yellow K7 channel.
First-off. The lines are not from Shade 7 (PiezoDN uses shades 1-6 only).
BUT, it looks like you may have a completely blocked channel. Did you manually PiezoFlush the yellow channel with the small format cleaning kit? Did you see it go onto the paper towel below the print-head? If you just put a PF cartridge in and did cleanings, this may not have done the job . . If you did manually PF the channel and you know the nozzles are clean and still nothing is coming through that there may be something electronically wrong with that channel. Your printer is still fully functional as a K6 printer btw.
Related to original problem, download the new QTR *2.7.8. It has a new “2880dpi Super” setting for this printer that helps A LOT to get rid of micro lines on older printers.
Thanks for the reply. Yes I cleaned it using small format cleaning kit and the yellow channel flowed through easily. Looks like it might be electrical. Have been using QTR 2.7.8 still get banding at around 97% on a grey scale ramp, printing as a negative. I’ll use it as a K6 printer, thanks for pointing that out.