Don't wipe the belt. Cleaning the belt (whichever part of the several you might be referencing by that term) will not help with the problem.
A stripe down the full length of a page, on every printout of a laser printer, usually indicates a damaged or dirty part in the machine. Open it up, take out what can be removed (if any part is a toner cartridge-like part, esp. if there's any shiny dark-bluish-greenish or else reddish-purplish cylinder showing, don't touch that with anything, nor clean it, nor expose it to bright light or illumination for longer than a half minute per 15 minutes - keep it in the dark awhile, while examining and cleaning inside the printer.
Look at all the parts, and swab dirt or lint away with a clean fresh swab or high-quality lint-free rag of cloth, or fresh paper towel. Make sure all rollers and roller-shaped elements are undamaged and unscratched (a scratch on some roller-shaped elements in the machine can produce the image defect you are having.)
Or follow the guide at HP Support for "Cleaning your printer" that applies to your model #:http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=125&prodSeriesId=446153&prodTypeId=18972&objectID=c00314469
And, if after that much examining nothing is found, and after that much cleaning and after you've reassembled it and tried printing again, the image defect is still there, then you need to try replacing the toner cartridge or all of them (I suppose there are three or four of them in your printer)... you will probably have to replace one of them at least, and if they are down to 1/4 capacity, it's almost time to do all of them anyway - unless ink is separate from the developer-containing cartridge that is probably the source of the problem. In which case, there might possibly be only one, and it would be non-colored. (HP's Support site is not helpful about replaceable parts for this model #, or I could be less general in my suggestions here.)
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