My HP DeskJet 990cxi printer (approx 18mths - 2 yrs old) has recently started to print lines of text in very dark grey. In a solid block of text, you can see that alternate lines are grey / black / grey / black etc all the way down the page.
I first tried cleaning the print heads (with the software clean and then manually cleaning the nozzles and contacts of the cartridge with a cotton wool bud) but to no avail.
I have also tried replacing the print cartridge - again no effect. I have emailed HP support once with this query but received a fairly bog-standard reply of diagnostics to try - they did specifically mention alternate grey / black lines so it must be a recognised problem, as I said the diagnostic page showed up no porblems. As I recently reformatted the HDD and reinstalled WinXP Pro, I have also reinstalled the HP Printer Driver. I am currently running it on the WInXP Driver as opposed to the latest HP Driver (it is another 15Mb Download I have not got around to yet) but we were running this driver before the re-build and the problem was still the same.
Has anyone else experienced this type of problem with an HP Printer (or other manufacturer) or have any other ideas? If this is a physical hardware fault as HP suggested tehn I am disappointed it has occured this early as I have had very good experiences of HP Products in the past, and often recommend them to others.
In case this problem arises again or if anyone else gets a similar problem, I've just read in a trouble-shooting guide that the alternate black/grey lines can occur when the printer is printing faster than the computer can transfer the required information to the printer. It would therefore sound as if the Spool settings or the "print direct to printer" setting should be looked at or at least considered. Hope this helps someone, sometime.