Samsung ml-2010 printer prints vertical lines on the page

I can print documents and the printer seems to be functioning normal but the output page has dark vertical lines on the front and the back of the page. The document text still shows up but the quality is obviuosly very poor with the dark vertical lines running down the page. The vertical lines are on both the front and the back of the page but they are darker on the front/print side of the output page. I have changed the toner cartridge and did not fix or effect the problem.