Patent ID: 7031635

Claim:
A toner cartridge, comprising a housing having a chamber for containing toner, an opening and an inner tube fixed to the housing and extending into the chamber in communication with the opening, wherein the inner tube is provided with a supporting portion at a distal end thereof and a hollow portion open to the chamber; a straight tube extending away from the housing in communication with the opening in the housing; a plug engaged in the straight tube having a through hole at a center thereof communicating with the opening in the housing, the plug comprising a fixing member fixed in the straight tube and an elastic washer disposed in the straight tube between the fixing member and the housing; wherein the fixing member and the elastic washer each have a hole which together form the through hole of the plug; wherein the diameter of the hole of the elastic member is smaller than that of the opening in the housing and also that of the hole in the fixing member; a stepped piston slidably engaged in the inner tube, wherein the piston has a resting portion having an outer diameter larger than that of the hole in the elastic washer and smaller than that of the opening in the housing and a protruding portion which can be squeezably engaged against the circumference of the hole of the elastic washer; and an elastic member disposed in the inner tube with opposite ends thereof respectively engaged to the supporting portion of the inner tube and the resting portion of the piston to bias the resting portion against the top surface of the washer and the protruding portion into engagement in the hole of the washer.