Quote Originally Posted by DAG COPIERS & COMPUTERS View Post
I would agree with the poster about replacing the the M laser, BTW, only last week I had exactly the same issue of magenta fading gradually until it eventually disappeared altogether from the printed copies. The machine? Not a canon color copier, but a HP LJ 2600n. The solution was simple, no need to replace the M laser; Simply removed the laser unit from the machine, opened the top cover and thoroughly cleaned the optics especially the reflecting mirror for the magenta, and the imaging lenses with a lint free cotton swab; I also did blowing off the dust in the unit. I took sometime doing the work, very carefully though considering it is a precision part. I also cleaned the ITB.
I was surprised with the resultant excellent prints after re-assembling. Somehow dust (and moisture?) seem to have found its way into the laser unit. Talk of trying 'to do something' before considering a replacement laser.
Well, that was an HP printer, for a canon, the story could be different.
What happens is the Lasers (Corrective Lens) displacement correction motor looses its home position and drives to the end of its range, you can sometimes wind it back but invariably it goes again.