Slight gray printed page background

[Pfilt]

I replaced the toner in my HP M402dw LaserJet printer for the first time. I put in a large HP 26x black toner cartridge. Letters and printing are now dark again. However, I've noticed a very slight grayness to the white, unprinted areas of the paper. The paper is no longer the crisp, very bright white I put into the printer. Some online advice suggested it might be a defective toner cartridge. So I had Staples replace it with another new cartridge. My discernible eye still sees a very light haze of gray in places. I use this printer occasionally with no problem before this toner change. The printer is relatively new and not used a whole lot. Pristine. What could be the cause? Will the very slight gray go away after some use? I looked inside the printer and found nothing dirty or out of the ordinary. I've run the Cleaning Page; but there's no change.

[Repairatrooper]

The cleaning page only removes excess toner from the fuser. In some cases you will get some background shading, if it does not clear up after printing about 100 pages it probably will not. Is your firmware up to date? What toner darkness setting are you using? Do the configuration pages printed from the control panel of the printer show the same issue? If not, check for updated firmware and drivers for the printer.

[Pfilt]

I have run 4 Cleaning Pages, and the problem persists. Both a Configuration Report page and a Demo page test have the same slight haze. I don't mind waiting a hundred pages or so you think the problem could clear up itself. What are the chances?