Such features or options should be stated in the specs of that printer. They won't try to hide any options as they'll promote offering this or that.
In most cases as in other printers, an envelope feeder is nothing more than width adj. feed slot and possibility yet another adj. for thickness as well to include which side it's done of the printer.
http://www.cdw.com/shop/products/default.aspx?EDC=1500611&cm_mmc=sendtec-_-adwords-_-Printer_Scanner-_-Ricoh_SP4100Nl_Printer&SendTecID=12069737 (check tech. specs below)
Media Type: Banners , Envelopes , Labels , Plain paper , Recycled paper , Transparencies
tada -----Willy ![]()
Does anyone know if this printer has an envelope feeder?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic