HP4050 tray 1 (envelop) doesn't feed

[total1]

HP4050N with tray 1 and tray 2 (no tray 3)
No duplex unit in use

My HP4050 (just received from a friend) won't feed envelopes without some strong 'encouragement'. The feeder wheel seems unable to pickup the envelopes. Tray 2 (paper tray) feeds fine. CHaracters are fully formed on all aspects of printing.
There appears to be some wear on the rubber wheel for tray 1.
What do I need to do or purchase? Is this an easy fix for someone who's never done any repair on an HP4050? [I don't intend on taking it in for service as I think I can do this, but I've never done whatever I need to do.]
Tremendous TIA!

[Strider]

The roller part# is RG5-3718-000CN.It is one of the easiest parts to replace on this printer.You grab the two tabs sticking out above the roller to remove the black plastic inner cover above the roller(it just pulls out).Then you look at the roller and pull the top of the blue tab toward you to loosen the roller.Then it lifts right off.Reassemble in reverse.It helps to use a small screwdriver to loosen the blue tab.

[total1]

Thanks, Strider. I'll get one on order so that I can be as experienced as you. Watch for the competition coming to a city near you! :-) Knowledgeable HP4050 technicians are in high demand. Pay at least 6 figures, starting at $0.00001, eh? :-)
Thanks!

[woodss]

I am writing to second that, it is the pick up roller, when you replace it make sure that you replace the seporation pad below the pick up roller.

Because the whenever the pickup roller is replaced the seporation roller needs to be replaced too, it also wouldnt hurt to clean or replace the rollers in tray two, and checking the fuser as well.

And it certainly wouldnt hurt to clean inside the printer, gently with a lint free cloth with a touch of filtered water.

And also cleaning the fan and its screen from dust that wouldnt hurt either.

All these suggestions is just routine maintaince.