After taking a more indepth look at the Drums and following your suggestion of swapping R1 drum with R4 the defect changed from Black Lines to Yellow Lines and as such after looking at the drum more closely I could see some lines on the drum itself.
I have left the R1 drum in R4 as now the yellow lines only appear when colour printing and no marks appear now when printing letters or black and white documents which will provide a work-around until the new drum arrives.
Many thanks for you assistance as always.
Anyone have an idea why we are getting repeating black line on all print outs, all colors. I've swapped the drums out several times (color and black) with different drums and we've also wipped down the ibt belt and these lines will not fade and seem to repeat like it was on a drum but the lines never change after swapping each drum and test printing. Attached is the image of the lines and suggestions??