There is a very quick, crude but successful way of accessing this belt.
Firstly, using a sharp 'Stanley' knife score and cut away a section, approx 9cms x3cms, of the lower edge of the printer casing, covering the drive belt.
The pulley wheels and belt can then be clearly seen. Refitting the belt around the pulleys will then take no more than a minute. When finished simply cover the casing hole with a piece of stiff card.
Job done.
John Bamber, February 2009