HP CP1025nw Color laserjet printing one line of color dots down middle of page

[j_don]

We have an HP CP1025nw color laser printer that has recently started printing colored dots down the center of each printed page. Originally it was all 4 color dots yellow, cyan, magenta and black. the 4dots a space and the 4 dots repeating down the entire page. I hard reset the printer. I updated firmware, I checked that it had the latest driver/software. I uninstalled and reinstalled with most recent software (2016). I ran calibration , I ran cleaning pages.

The dots are now in a pattern of two dots space, two dots.. All 4 colors are still represented but like i said only two dots atr a time than a space

W e did recently replace the toners, but don't want to replace all 4 again.

[Apone]

it sounds like bad toner, but here is something to try:  half cycle test

load one sheet into the printer, send a single, color print job.  BEFORE the paper has time to reach the fuser (most often this requires a couple tries) stop the print by manually opening the toner access door. look under the toner at the printed image, is the defect there?  if so, chances are the toner is having issues.