Q: The image units are new and machine has only 250,000 prints.
A: Try identifying if the lines are in one particular colour. Print off a page of one of each colour; cyan, magenta, yellow and black and determine if the lines are in one colour. If it is only in one colour, swap the drums over with another colour. If the lines don't move with the drum, it could require a service engineer to have a look at it. If the problem in through all 4 colours, it could be caused by the fuser or 2nd BTR, again an engineer will need to service this.