HP 2840 Color LaserJet creating 1 single band

Sure hope someone can help. This printer used to print perfect black/white & color pages. It has about 1700 pages run thru it according to the Supply/Status Utlity. It sat for 6 mos & after going back in service it is producing a vertical band about 2" from the left of every page.

Now this vertical band can vary in width from 1/8" when doing a self-test/config page (color) to 3/4" in black & white. Even a full color page will produce a marked band in the same location but the color still looks good.

Anyone have any ideas, hints or guidance?