4000 and 4050 graphics print quality?

[pmperfect]

We have a 4000 and a 4050 that we use to print photos and text onto UV Ultra II paper. We have had both of these printers for over 3 years. I do routine maintenance and have recently replaced the transfer roller, fuser and pickup rollers. We use a new cartridge every 2 to 3 weeks. Over time the graphics print quality has suffered. The images are not as smooth as they use to be. What other part is there to replace that affects print quality?

[MichaelTech]

A worn toner could affect quality, also if the feed assy. is worn and the paper is slipping a bit, it would give you bad print.
Networked or parallel? A bad NIC can mess up the file sent.
Paper quality can be the culprit too. Check printing with new batch of paper.
If you have had any toner leakage, it would be at the contacts for the transfer roller. Also on the ECU where the contact wires touch may have toner on them.

[Strider]

Over time the mirrors and lenses in the laser/scanner get dirty which leads to lighter and uneven print quality.Use a gentle touch while cleaning them as you will be cleaning the silvered side of the mirrors and the lenses are made of a fairly soft plastic.you must remove and open the laser unit to gain access to these parts.Good luck.