3250 misprinting at top of sheet

[N7DR]

I have been doing some testing, and the problem appears to occur only when I have double-sided printing enabled (even if printing a single sheet). If I print a single sheet but with double-sided printing enables, the problem occurs at the top of the page; if I do exactly the same, but disable double-sided printing, the printer seems to print properly.

[N7DR]

Starting a couple of days ago, my 3250 has started misprinting by leaving the first few lines blank, then producing a narrow fuzzy black line across the width of the sheet, and then printing the rest of the sheet correctly.

I created the following by trying to point a document that looked like this:

 A1

  B1

   C1

    D1 ... etc, up to L1

The following is a scan of a complete printed page. The gap below this text is the blank part where the printer has stopped printing properly. The line throught the "C1" below is the fuzzy black line that the printer is now producing.

Also, for about a quarter of an inch below the black line, the printing appears to be a little compressed vertically.