Toner housing plug with toner level sensor

A toner fill plug for a toner cartridge within an image forming device. The cartridge includes a toner reservoir having a port through which toner is input. The plug is sized to fit within the port and prevent toner leakage. The plug includes a reflector which aligns with an adjacently-positioned toner level sensor for determining the amount of toner remaining within the reservoir. The plug is removable to allow the user to refill the reservoir with new toner.

BACKGROUND

Cartridges used in image forming devices include toner to form an image on a media sheet. A number of different sensing mechanisms have been used for detecting the amount of toner remaining within the cartridge. One detection method includes detecting the amount of torque applied to an agitating member that rotates through the toner. The torque on the agitating member can be sensed to determine the remaining amount of toner.

Another method includes optical detecting using an optical sensor that radiates a light beam through a transparent window in the cartridge. In one embodiment, an emitter directs a light beam through an opening in the cartridge. The light beam reflects off a surface within the cartridge and is detected by a sensor positioned next to the emitter. The amount of reflected light determines the remaining amount of toner. In another embodiment, a second opening is positioned in the cartridge opposite from the first opening. The sensor is positioned at the second opening to receive the light beam directly from the emitter. Again, the amount of detected light determines the remaining amount of toner.

The cartridge may be used in the image forming device until the toner is exhausted. The cartridge is then removed from the device and replaced with a new cartridge. The exhausted cartridge is then either discarded, or refilled with new toner. The cartridge should have some manner of gaining access to the interior to allow for new toner to be refilled and used again within the image forming device. The refilling mechanism should provide a durable seal to prevent toner from leaking during the image formation process. The access point should also be positioned at a location on the cartridge to not interfere with the other cartridge mechanisms.

SUMMARY

The present invention is directed to a toner fill plug for a toner cartridge within an image forming device. The cartridge includes a toner reservoir having a port through which toner is input. A plug extends over the port and is sized to seal the port and prevent toner leakage. The plug includes a reflector that is positioned within the reservoir when the plug is mounted to the port. The reflector reflects a signal radiated by an adjacently-positioned toner level sensor for determining the amount of toner remaining within the reservoir. The plug is removable to allow for the user to refill the reservoir with new toner.

DETAILED DESCRIPTION

The present invention is directed to a toner fill plug30that prevents toner from leaking from a port23in a toner cartridge20. The plug30includes a reflector31that reflects a light signal radiated from a toner level sensor40for determining the amount of toner remaining within the cartridge20. The plug30may be removed for refilling new toner into a reservoir62within the cartridge20.

The plug30includes a seal34, base32, and a reflector31as illustrated inFIG. 1. The seal34is sized to fit within the port23and prevent toner from leaking from the cartridge20. In one embodiment, the seal34has an elliptical shape with a lip36and an outer rim35that extends around the exterior of the lip36. When inserted in the port23, the lip36contacts the edge of the port23, and the outer rim35contacts the outer edge of the cartridge20. An aperture37is positioned within the seal34to contain a window41. In one embodiment, the aperture37is positioned within the center of the seal34.

The elliptical shape of the seal34seats the lip and outer rim35within the port23. In one embodiment, the elliptical shape has a length major axis of about 30.7 mm and a minor axis of about 14.94 mm. The seal34may be constructed from a variety of materials. In one embodiment, the material is elastic to conform to the dimensions of the port23. In one embodiment, the seal34is constructed of a polycarbonate.

Base32extends outward from the seal34. The length of the base32may vary depending upon the desired location of the reflector31. One or more apertures33are positioned on a distal end of the base32opposite the seal34.

Reflector31extends outward from the base32at a predetermined distance from the window41. In one embodiment, the reflector31is spaced from the window41a distance of about 9 mm, and should not exceed a distance of more than about 40 mm. The reflector31reflects the signal emitted from the toner level sensor40. The reflector31and base32may be a one-piece member integrally formed together, or the reflector31may be a separate piece attached to the base32. In one embodiment, the reflector31is an aluminized plastic sheet attached to support member. The reflector31extends upward from the base32at a point between the seal34and the apertures33.

One or more retention features21extend outward into the internal reservoir62. The retention features21are sized to mount within the apertures33of the base32and maintain the plug30attached to the cartridge20. In one embodiment, retention features have a ramped shape with an angled surface that slant away from the port23.

The port23is positioned on the cartridge20at a location not to interfere with the elements used in the image formation process, such as the developer roll and toner adder roll. In one embodiment, a bottom edge of the port23is substantially aligned with a bottom of the reservoir62. This position allows the base32to slide across the bottom of the cartridge during installation, and for the apertures33to mount to the retention features21which extend outward from a lower wall of the internal reservoir62.

An agitating member25is positioned within the cartridge20to stir and move the toner. The agitating member25includes a shaft124and a blade125. The shaft124rotates with the blade125stirring and moving the toner within the internal reservoir62. The sweep of the blade125extends across the port23and plug30. The blade125includes a first edge27and a second edge28spaced a distance apart. The first edge27sweeps across the reflector31and the second edge28sweeps across the window41during each rotation. The sweeping motion keeps both the reflector31and window41clear to allow light from the toner level sensor40to pass back and forth between the window41and reflector31.

Toner level sensor40detects the amount of toner remaining within the cartridge20. The toner level sensor40includes an emitter42that radiates infrared light, and a receiver43that detects the reflected light from the reflector31. In one embodiment, the sensor40is mounted in the image forming device at a position to be adjacent to the window41when the cartridge20is installed. In another embodiment, the sensor40is attached to the plug30.

The emitter42emits an infrared light through the window41towards the reflector31. A strong reflected signal is received by the receiver43when there is no toner within the reservoir62. No signal or a weak signal is detected by the receiver43when toner within the reservoir is to a level to block the light from contacting or being reflected by reflector31.

Various types of emitters42and receivers43may be used and are considered within the scope of the present invention. In one embodiment, the emitter42and receiver43are separate elements.

Window41is an optically transmissive member mounted within the aperture37of the seal34. The window41may be any material which is transparent to infrared light and is sturdy enough to hold toner within the cartridge20. In one embodiment, the window41is made of polycarbonate. In one embodiment, the window41has a surface that is substantially parallel with a reflective surface of the reflector31

Removal of the plug30is necessary to refill toner within the cartridge20. In one embodiment as illustrated inFIG. 5, an opening190is formed in the plug30for inserting a tool178, such as a screwdriver. Once inserted, a downward force F is applied to the screwdriver to remove the apertures33on the base32from the retention features21within the cartridge20. Once removed, the plug30can be removed and new toner refilled through the port23. In one embodiment, a first opening190is formed in the seal34, and a second opening191is formed in the reflector31. In yet another embodiment, the plug30can be removed by a user grasping the outer edges of the seal34and applying a removal force.

Examples of cartridges for use in the present invention are those found in Printer Model Nos. C750 and C752 available from Lexmark, International, Inc, of Lexington, Ky. U.S. Pat. No. 6,496,662 assigned to Lexmark International Inc discloses other cartridges, plugs, and toner level sensors, and is herein incorporated by reference in its entirety.

Placement of the reflector31on the removal plug30assists in refilling the cartridge20with toner. The reflector31is removed with the plug during refilling and does not slow or prevent the toner from entering the cartridge. If the reflector31was permanently mounted within the cartridge20, it may interfere with the refilling process and act as a dam to prevent toner from entering through the port23.

The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. In one embodiment, seal34is a separate element that attaches to the body of the plug30. In another embodiment, additional sealing elements such as neoprene, felt, or caulk prevent toner leakage. These additional sealing elements may be attached to the plug30, to the cartridge20, or applied separately. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.