pengtao, you've point my problem ! I have Default Folder installed, and when it's disable, the problem disappear.
I've seen the problem noticed on Default Folder macupdate page, so I'll hope a fix will soon come.
Thanks pengtao !
Pentao, you are the MAN! I too have Default Folder X installed... I just went to my system preferences, turned Defualt Folder X OFF and voila! The printer proxy goes away automatically now after printing. Problem SOLVED! (for me at least), THANKS!