HP 2840 all in one lines on the page

I have a HP 2840 and I am getting lines on the left side of the page. I think maybe it needs to be cleaned, but I'm not sure of the best way to do this. I would prefer not to have to call someone in for service as it would be quite expensive. Is there something else I could do, maybe something less expensive to use? Anyu help/suggestions would be apprecated.

Lisa