Should have tried harder to clean the device before posting this.
Since the image contamination was a vertical line and appeared when I used the document feeder, I first tried a flatbed scan and verified the problem didn't occur. Then cleaned the DADF thoroughly and resolved the issue.
This often happens to me. When problems with any device occurs, I tend to think that it is something serious that only a specialist can get it done.It's a good thing that I am with people who have a knack on DIY. It is always good to go for simple remedies like cleaning before going on panic mode.