HP LaserJet 4050TN New Fuser Problem

[JC5409]

I installed a maintenance kit on a HP LaserJet 4050TN. After the install
I ran some test pages on plain paper and they printed fine. However anything printed on letterhead or envelopes was not fused properly "loose toner", I then ran some plain paper again and the problem cleared up. I was able to correct the letterhead issue from the paper-handling menu on the control panel; I changed the fuser mode setting for letterhead to "HIGH". The envelope feeder on tray one will not print envelopes correctly no matter which paper type or speed I select - it always prints with loose toner. I then pulled a fuser from an HP LJ 4000 and tested it in the LJ 4050TN and the envelopes printed properly. Is the new fuser defective or is there a setting that I am missing?? Any suggestions??

[MikeB]

A bad fuser from the factory is not all that odd. If a different known good fuser had no issues, then I'd definately return the new fuser from whence it came and try to get an exchange from them. Usually fusers are refurbished and recirculated so getting "new" bad fusers should not be cause for alarm.

[ptjeff1]

If the fuser you got was brand new from the factory then there is a possiblity that HP changed suppliers for some of the parts in the fuser, or slightly changed formulations. So your old fuser might not have the problem but the new one does. If you got a rebuilt fuser you might contact the seller. Not all companies test their fusers on heavy stock. We test on labels and plain paper. Labels are a heavier stock, but with envelopes you are pushing the limits of the printer. Envelopes are essentially two pieces of paper. The combination of heat and pressure in the fuser isn't enough to melt the toner to the envelope. I run envelopes in my LJ 4050 and don't have any problems, but I might be using an envelope with thinner paper.