CN108369393B

CN108369393B - Replaceable unit for a magnet of an image forming device having varying angular offset for toner level sensing

Info

Publication number: CN108369393B
Application number: CN201580084924.7A
Authority: CN
Inventors: 布莱恩·斯科特·卡彭特; 罗伯特·沃森·麦克阿尔菲; 迈克尔·克雷格·里姆豪斯
Original assignee: Lexmark International Inc
Current assignee: Lexmark International Inc
Priority date: 2015-11-30
Filing date: 2015-12-01
Publication date: 2021-02-09
Anticipated expiration: 2035-12-01
Also published as: CN108369393A; CA3004256A1; CA3004256C; EP3384349A4; WO2017095392A1; EP3384349B1; EP3384349A1; HK1256722A1

Abstract

According to one example embodiment, a replaceable unit for an electrophotographic image forming apparatus includes a housing having a reservoir for storing toner. A rotatable shaft is disposed within the reservoir and has an axis of rotation. The first and second magnets are connected to the shaft and are rotatable about an axis of rotation in response to rotation of the shaft. The first magnet and the second magnet are detectable by the magnetic sensor when the replaceable unit is installed in the image forming apparatus. The polarity of the first magnet is oppositely oriented with respect to the polarity of the shaft from the polarity of the second magnet. The amount of angular displacement between the first magnet and the second magnet varies depending on the amount of toner in the reservoir.

Description

Replaceable unit for a magnet of an image forming device having varying angular offset for toner level sensing

Background

1. Field of disclosure

The present disclosure relates generally to image forming devices and, more particularly, to a replaceable unit for a magnet of an image forming device having a varying angular offset for toner level sensing.

2. Description of the related Art

In an electrophotographic printing process, a charged rotating photosensitive drum is selectively exposed to a laser beam. The areas of the photosensitive drum exposed to the laser beam are discharged, creating an electrostatic latent image of the page to be printed on the photosensitive drum. The toner particles are then electrostatically picked up by the latent image on the photosensitive drum, producing a colored image on the drum. The toned image is transferred to a printing medium (e.g., paper) directly from the photosensitive drum or indirectly from an intermediate transfer member. The toner is then fused to the media using heat and pressure to complete the print.

Toner supplies for image forming apparatuses are typically stored in one or more replaceable units installed in the image forming apparatus. When the replaceable units run out of toner, the units must be replaced or refilled to facilitate continued printing. Therefore, it is desirable to measure the amount of toner remaining in these units in order to alert the user that one of the replaceable units is nearly empty or to avoid printing after one of the units is empty to avoid damage to the image forming apparatus. Accordingly, a system for measuring the amount of toner remaining in a replaceable unit of an image forming apparatus is desired.

SUMMARY

The implementation mode comprises the following contents: wherein one of the north and south poles of the first magnet is directed outwardly away from the shaft and the other of the north and south poles of the second magnet is directed outwardly away from the shaft.

In certain embodiments, the first magnet is substantially axially aligned with the second magnet about the axis of rotation. In certain embodiments, the first magnet is substantially radially aligned with the second magnet about the axis of rotation.

The implementation mode comprises the following contents: wherein the first linkage is rotatable with the shaft and is rotatable independently of the shaft between a forward rotational stop and a rearward rotational stop. The second magnet is mounted on the first linkage. In some embodiments, the second linkage is fixed to rotate with the shaft, and the first magnet is mounted on the second linkage. In some embodiments, the first linkage has a paddle member that leads the first magnet in the operational rotational direction of the shaft, and the second magnet lags the first magnet in the operational rotational direction of the shaft. The paddle member may include a third magnet. In some embodiments, the first linkage is biased in the operational rotational direction of the shaft toward the forward rotation stop by a biasing member.

A replaceable unit for an electrophotographic image forming apparatus according to a second example embodiment includes a housing having a reservoir for storing toner. A rotatable shaft is disposed within the reservoir and has an axis of rotation. The first and second magnets are connected to the shaft and are rotatable about an axis of rotation in response to rotation of the shaft. The first and second magnets pass adjacent to at least a portion of an inner wall of a housing forming the reservoir during rotation of the first and second magnets. The first pole of the first magnet points outwardly away from the shaft and the second pole of the second magnet points outwardly away from the shaft. The polarity of the first pole is opposite to the polarity of the second pole. The amount of angular displacement between the first magnet and the second magnet varies depending on the amount of toner in the reservoir.

A replaceable unit for an electrophotographic image forming apparatus according to a third example embodiment includes a housing having a reservoir for storing toner. A rotatable shaft is disposed within the reservoir and has an axis of rotation. The first, second, and third magnets are connected to the shaft and rotatable about an axis of rotation in response to rotation of the shaft. The first, second, and third magnets pass adjacent to at least a portion of an inner wall of a housing forming the reservoir during rotation of the first, second, and third magnets. The second magnet leads the first magnet in the operational rotational direction of the shaft and the third magnet lags the first magnet in the operational rotational direction of the shaft. The amount of angular displacement between the first magnet and the second magnet and the amount of angular displacement between the first magnet and the third magnet vary depending on the amount of toner in the reservoir.

Brief Description of Drawings

The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present disclosure, and together with the description serve to explain the principles of the disclosure.

FIG. 1 is a block diagram of an imaging system according to an example embodiment.

FIG. 2 is a perspective view of a toner cartridge and an imaging unit according to one example embodiment.

Fig. 3 and 4 are additional perspective views of the toner cartridge shown in fig. 2.

FIG. 5 is an exploded view of the toner cartridge shown in FIG. 2 showing a reservoir for holding toner therein.

FIG. 6 is a perspective view of a paddle assembly of a toner cartridge according to one example embodiment.

7A-C are cross-sectional side views of a toner cartridge depicting operation of the sensing linkage at various toner levels according to one example embodiment.

FIG. 8 is a graph of the angular separation between the reference magnet and the sensing magnet as they pass the point of the magnetic sensor relative to the amount of toner remaining in the reservoir of the toner cartridge, according to one example embodiment.

FIG. 9A is a perspective view of a sensing linkage according to a second example embodiment.

FIG. 9B is a perspective view of a sensing linkage according to a third example embodiment.

FIG. 9C is a perspective view of a sensing linkage according to a fourth example embodiment.

FIG. 10 is a perspective view of a paddle assembly of a toner cartridge according to another example embodiment.

Detailed Description

In the following description, reference is made to the accompanying drawings in which like numerals represent like elements. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the present disclosure. Examples merely typify possible variations. Portions and features of some embodiments may be included in or substituted for those of others. The following description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims and equivalents thereof.

Referring now to the drawings and in particular to FIG. 1, a block diagram depiction of an imaging system 20 according to an example embodiment is illustrated. The imaging system 20 includes an image forming device 22 and a computer 24. Image forming device 22 communicates with computer 24 via a communication link 26. As used herein, the term "communication link" generally refers to any structure that facilitates electronic communication between components, and which may operate utilizing wired or wireless technology, and may encompass communication over the internet.

In the example embodiment shown in FIG. 1, image forming device 22 is a multi-function machine (sometimes referred to as an all-in-one (AIO) device) that includes a controller 28, a print engine 30, a Laser Scanning Unit (LSU)31, an imaging unit 32, a toner cartridge 35, a user interface 36, a media loading system 38, a media input tray 39, and a scanner system 40. The image forming device 22 may communicate with the computer 24 via a standard communication protocol, such as Universal Serial Bus (USB), ethernet, or ieee802. xx. The image forming device 22 may be, for example, an electrophotographic printer/copier that includes an integrated scanner system 40 or a stand-alone electrophotographic printer.

The controller 28 comprises a processor unit and associated memory 29. The processor may comprise one or more integrated circuits in the form of a microprocessor or central processing unit, and may be formed as one or more Application Specific Integrated Circuits (ASICs). The memory 29 may be any volatile or non-volatile memory, or combination thereof, such as Random Access Memory (RAM), Read Only Memory (ROM), flash memory, and/or non-volatile RAM (NVRAM). Alternatively, memory 29 may be a stand-alone electronic memory (e.g., RAM, ROM, and/or NVRAM), a hard disk drive, a CD or DVD drive, or any form of memory device for use with controller 28. The controller 28 may be, for example, a combined printer and scanner controller.

In the illustrated example embodiment, controller 28 communicates with print engine 30 via a communication link 50. Controller 28 communicates with imaging unit 32 and processing circuitry 44 thereon via a communication link 51. Controller 28 communicates with toner cartridge 35 and processing circuitry 45 thereon via communication link 52. The controller 28 communicates with the media loading system 38 via a communication link 53. The controller 28 communicates with the scanner system 40 via a communication link 54. The user interface 36 is communicatively coupled to the controller 28 via a communication link 55.

Processing circuits

44, 45 may provide authentication functions, safety and operational interlocks, operating parameters, and usage information regarding imaging unit 32 and toner cartridge 35, respectively. The controller 28 processes print and scan data and operates the print engine 30 during printing and the scanner system 40 during scanning.

The computer 24, which is optional, may be, for example, a personal computer that includes memory 60, such as RAM, ROM, and/or NVRAM, an input device 62, such as a keyboard and/or mouse, and a display 64. The computer 24 also includes a processor, input/output (I/O) interfaces, and may include at least one mass data storage device, such as a hard disk drive, CD-ROM, and/or DVD unit (not shown). The computer 24 may be a device capable of communicating with the image forming device 22, such as a tablet computer, a smart phone, or other electronic devices, for example, in addition to a personal computer.

In the illustrated example embodiment, the computer 24 contains in its memory a software program containing program instructions that function as an imaging driver 66 (e.g., printer/scanner driver software) for the image forming device 22. Imaging driver 66 communicates with controller 28 of image forming device 22 via communication link 26. The imaging driver 66 facilitates communication between the image forming apparatus 22 and the computer 24. One aspect of imaging driver 66 may be, for example, to provide formatted print data to image forming device 22, and more particularly to print engine 30 to print an image. Another aspect of the imaging driver 66 may, for example, cause the collection of scanned data from the scanner system 40.

In some cases, it may be desirable to operate image forming device 22 in a standalone mode. In the standalone mode, the image forming apparatus 22 can operate without the computer 24. Accordingly, all or a portion of imaging driver 66, or a similar driver, may be located in controller 28 of image forming device 22 to accommodate printing and/or scanning functions when operating in a standalone mode.

The print engine 30 includes a Laser Scanning Unit (LSU)31, a toner cartridge 35, an image forming unit 32, and a fuser 37, all of which are installed within the image forming apparatus 22. Imaging unit 32 is removably mounted in image forming device 22 and includes a developer unit 34 that houses a toner cartridge and a toner delivery system. In one embodiment, the toner delivery system utilizes what is commonly referred to as a single component development system. In this embodiment, the toner delivery system includes a toner adder roller that provides toner from the toner cartridge to the developer roller. The doctor blade provides a metered uniform layer of toner on the surface of the developer roller. In another embodiment, the toner delivery system utilizes what is commonly referred to as a two component development system. In this embodiment, the toner in the toner cartridge of developer unit 34 mixes with the magnetic carrier beads. The magnetic carrier beads may be coated with a polymeric film to provide triboelectric properties to attract toner to the carrier beads as they are mixed in the toner cartridge. In this embodiment, the developer unit 34 includes a magnetic roller that attracts magnetic carrier beads having toner thereon to the magnetic roller through the use of a magnetic field.

The image forming unit 32 also includes a cleaner unit 33 that houses the photosensitive drum and the waste toner removal system. Toner cartridge 35 is removably mounted in image forming device 22 in mating relationship with developer unit 34 of imaging unit 32. The outlet port on toner cartridge 35 communicates with the inlet port on developer unit 34, allowing toner to be periodically transferred from toner cartridge 35 to replenish the toner cartridge in developer unit 34.

Electrophotographic printing processes are well known in the art and are therefore described briefly herein. During a printing operation, the laser scanning unit 31 generates a latent image on the photosensitive drum in the cleaner unit 33. Toner is transferred from a toner cartridge in developer unit 34 to the latent image on the photosensitive drum by a developer roller (in the case of a one-component development system) or by a magnetic roller (in the case of a two-component development system) to produce a toned image. The toned image is then transferred to a media sheet received by imaging unit 32 from media input tray 39 for printing. Toner may be transferred directly to the media sheet by the photosensitive drum or by an intermediate transfer member that receives toner from the photosensitive drum. The remaining toner is removed from the photosensitive drum by a waste toner removal system. The toner image is bonded to the media sheet in fuser 37 and then sent to an output location, or one or more finishing options, such as a duplex printer, a stapler, or a hole punch.

Referring now to FIG. 2, toner cartridge 100 and imaging unit 200 are shown, according to one example embodiment. The imaging unit 200 includes a developer unit 202 and a cleaner unit 204 mounted on a common frame 206. As described above, the image forming unit 200 and the toner cartridge 100 are detachably mounted in the image forming apparatus 22. The image forming unit 200 is first slidably inserted into the image forming apparatus 22. Toner cartridge 100 is then inserted into image forming device 22 and onto frame 206 in mating relationship with developer unit 202 of imaging unit 200, as indicated by the arrows shown in FIG. 2. This arrangement allows toner cartridge 100 to be easily removed and reinserted without having to remove imaging unit 200 when replacing an empty toner cartridge 100. Imaging unit 200 may also be easily removed as needed to facilitate maintenance, repair, or replacement of components associated with developer unit 202, cleaner unit 204, or frame 206, or to preclude jamming of media.

Referring to fig. 2-5, toner cartridge 100 includes a housing 102, housing 102 having an enclosed reservoir 104 (fig. 5) for storing toner. The housing 102 may include a top or cover 106 mounted over a base 108. The base 108 includes first and

second sidewalls

110, 112 connected by adjacent front and

rear walls

114, 116 and a bottom 117. In one embodiment, the top 106 is ultrasonically welded to the base 108, thereby forming the enclosed reservoir 104. First and second end caps 118, 120 may be mounted to

sidewalls

110, 112, respectively, and may include guides 122 to facilitate insertion of toner cartridge 100 into image forming device 22 for mating with developer unit 202. The first and second end caps 118, 120 may be snapped into place or attached by screws or other fasteners. Guides 122 travel in corresponding channels within image forming device 22. Legs 124 may also be provided on bottom 117 of base 108 or on

end caps

118, 120 to assist in the insertion of toner cartridge 100 into image forming device 22. Leg 124 is received by frame 206 to facilitate engagement of toner cartridge 100 with developer unit 202. Handle 126 may be disposed on top 106 or base 108 of toner cartridge 100 to facilitate insertion and removal of toner cartridge 100 from imaging unit 200 and image forming device 22. Outlet port 128 is provided on front wall 114 of toner cartridge 100 for toner to exit from toner cartridge 100.

Referring to fig. 5, various drive gears are housed within the space formed between the endcap 118 and the sidewall 110. The main interface gear 130 meshes with a drive system in the image forming apparatus 22, and the drive system supplies torque to the main interface gear 130. Paddle assembly 140 is rotatably mounted within toner reservoir 104 with first and second ends of drive shaft 132 of paddle assembly 140 extending through aligned openings in

sidewalls

110, 112, respectively. A drive gear 134 is provided on a first leg of the drive shaft 132, which meshes with the primary interface gear 130, either directly or via one or more intermediate gears. Bushings may be provided on each end of the drive shaft 132 that pass through the

side walls

110, 112.

An auger 136 having first and

second ends

136a, 136b and a helical thread is disposed in a channel 138 extending between the

side walls

110, 112 along the width of the front wall 114. The channel 138 may be integrally molded as part of the front wall 114 or formed as a separate member attached to the front wall 114. When toner cartridge 100 is installed in image forming device 22, channel 138, and thus toner cartridge 100, is generally horizontal in orientation. A first end 136a of auger 136 extends through sidewall 110 and a drive gear (not shown) is disposed on first end 136a that meshes with primary interface gear 130, either directly or via one or more intermediate gears. The channel 138 may include an open portion 138a and a closed portion 138 b. Open portion 138a is open to toner reservoir 104 and extends from sidewall 110 toward second end 136b of auger 136. A closed portion 138b of channel 138 extends from sidewall 112 and closes the optional gate and second end 136b of auger 136. In this embodiment, outlet port 128 is disposed at the bottom of closed portion 138b of channel 138, so gravity will assist in the exit of toner through outlet port 128. The shutter is movable between a closed position blocking toner from exiting outlet port 128 and an open position allowing toner to exit outlet port 128.

As paddle assembly 140 rotates, it transfers toner from toner reservoir 104 into open portion 138a of channel 138. As auger 136 rotates, it passes toner received in channel 138 to closed portion 138b of channel 138, where it passes out of outlet port 128 into a corresponding inlet port 208 in developer unit 202 (fig. 2). In one embodiment, inlet port 208 of developer unit 202 is surrounded by foam seal 210, foam seal 210 capturing residual toner and avoiding toner leakage at the interface between outlet port 128 and inlet port 208.

The drive system in image forming device 22 includes a drive motor and drive transmission from the drive motor to a drive gear that mates with primary interface gear 130 when toner cartridge 100 is installed in image forming device 22. The drive system in image forming device 22 may include a coded device (e.g., a shaft coupled to a drive motor) such as a coded wheel and an associated code reader such as an infrared sensor to sense motion of the coded device. The code reader communicates with the controller 28 so as to allow the controller 28 to track the amount of rotation of the primary interface gear 130, auger 136, and paddle assembly 140.

2-5 include pairs of replaceable units in the form of toner cartridge 100 and imaging unit 200, it will be appreciated that the replaceable units of the image forming apparatus may utilize any suitable configuration as desired. For example, in one embodiment, the primary toner supply, developer unit, and cleaner unit for the image forming apparatus are housed in a replaceable unit. In another embodiment, the primary toner supply and developer unit for the image forming apparatus is provided in a first replaceable unit and the cleaner unit is provided in a second replaceable unit. Also, although the example image forming device 22 discussed above includes a toner cartridge and a corresponding imaging unit, in the case where the image forming device is configured for color printing, a separate replaceable unit may be used for each toner color desired. For example, in one embodiment, an image forming apparatus includes four toner cartridges, each containing a particular toner color (e.g., black, cyan, yellow, and magenta), and four corresponding image forming units, each corresponding to one of the toner cartridges to allow color printing.

Fig. 6 illustrates paddle assembly 140 in greater detail according to an exemplary embodiment. In operation, the shaft 132 rotates in the direction shown by arrow a in fig. 6. The paddle assembly 140 includes a fixed paddle 141 that is fixed to the shaft 132 such that the fixed paddle 141 rotates with the shaft 132. In one embodiment, the shaft 132 extends from the sidewall 110 to the sidewall 112. In the depicted embodiment, fixed paddle 141 includes a plurality of arms 142 extending radially from shaft 132. In the depicted example embodiment, the fixed paddle 141 includes two

sets

142a, 142b of arms 142. In this embodiment, in the position depicted in fig. 6, the arms 142 of the first set 142a extend from the shaft 132 toward the rear wall 116, and the arms 142 of the second set 142b extend from the shaft 132 toward the front wall 114. Of course, these positions change as the shaft 132 rotates. The arm portions 142 of each

set

142a, 142b are radially aligned with one another and axially offset. The arms 142 of the first set 142a are circumferentially offset from the arms 142 of the second set 142b by about 180 degrees. Other embodiments include one set of arms 142 or more than two sets of arms 142 extending from the shaft 132. In other embodiments, the arms 142 are not arranged in groups. Again, the arms 142 may extend radially or non-radially from the shaft 132 in any manner desired.

The fixed paddle 141 may include a cross member 144 connected to the arm 142 of each

set

142a, 142 b. Cross member 144 may extend across all or a portion of the arms of

sets

142a, 142 b. Cross member 144 helps arm 142 to agitate and mix toner in reservoir 104 as shaft 132 rotates. A breaker bar 146, generally parallel to the shaft 132, may be disposed radially outward from each cross member 144 and connected to the distal end of the arm 142. The crusher 146 is positioned in close proximity to the inner surface of the housing 102 without contacting the inner surface of the housing 102 to help break up toner clumped proximate to the inner surface of the housing 102. The scraper blade 148 may extend from the cross member 144 in a cantilevered fashion. Blade 148 is formed of a flexible material such as polyethylene terephthalate (PET) material, such as that available from DuPont Teijin Films of Chester, Virginia, USA

Doctor blade 148 forms an interference fit with the inner surfaces of top 106, front wall 114, rear wall 116, and bottom 117 to wipe toner from the inner surface of reservoir 104. As shaft 132 rotates, doctor blade 148 also pushes toner into the channel138 open portion 138 a. Specifically, as cross member 144 rotates from bottom 117 through open portion 138a of channel 138 to top 106, the interference fit between blade 148 and the inner surface of front wall 114 causes blade 148 to have an elastic response as blade 148 passes through open portion 138a of channel 138, thereby flicking or pushing toner toward open portion 138a of channel 138. Additional blades may be provided on the axially distal arms 142 of shaft 132 as needed to wipe toner from the inner surfaces of

sidewalls

110 and 112. The arrangement of fixed paddle 141 shown in fig. 6 is not intended to be limiting. The fixed paddle 141 may include any suitable combination of protrusions, agitators, paddles, scrapers, and linkages as needed to agitate and move the toner stored in the reservoir 104.

In the depicted example embodiment, the permanent magnet 150 may rotate with the shaft 132 and may be detected by a magnetic sensor as discussed in more detail below. In one embodiment, magnet 150 is connected to shaft 132 by fixed paddle 141. In the depicted example embodiment, the first set 142a of arms 142 includes a pair of axially spaced arms 143 disposed at axial ends of the shaft 132. The arms 143 initially extend radially outward from the shaft 132 and then bend at the distal ends of the arms 143 opposite the operational rotational direction of the shaft 132. A cross member 145 connects the distal ends of the arms 143 and extends substantially parallel to the shaft 132. In the illustrated example embodiment, the magnet 150 is disposed in a finger 152, the finger 152 extending outwardly from the cross member 145 toward the inner surface of the housing 102. The fingers 152 extend in close proximity to the inner surface of the housing 102 but do not contact the inner surface of the housing 102 such that the magnet 150 is disposed in close proximity to the inner surface of the housing 102. In one embodiment, fixed paddle 141 comprises a non-magnetic material and magnet 150 is held by a friction fit within a recess in finger 152. Magnet 150 may also be attached to finger 152 with an adhesive or fasteners as long as magnet 150 will not disengage from finger 152 during operation of toner cartridge 100. The magnet 150 may be of any suitable size and shape so as to be detectable by a magnetic sensor. For example, the magnet 150 may be a cube, a rectangle, an octagon, or another form of prism, a sphere or cylinder, a sheet, or an amorphous object. In another embodiment, the finger 152 includes a magnetic material such that the body of the finger 152 constitutes the magnet 150. The magnet 150 may be constructed of any suitable material, such as steel, iron, nickel, etc. Although the example embodiment depicted in fig. 6 shows the magnet 150 mounted on the finger 152 of the fixed paddle 141, the magnet 150 may be disposed on any suitable linkage connected to the shaft 132, such as a cross member, arm, tab, finger, stirrer, paddle, etc. of the fixed paddle 141, or separate from the fixed paddle 141.

Sensing linkage 160 is mounted to shaft 132. Sensing linkage 160 rotates with shaft 132, but may move somewhat independently of shaft 132. Sensing linkage 160 is free to rotate forward and backward on shaft 132 relative to fixed paddle 141 and relative to magnet 150 between the forward and rearward rotational stops. Sensing linkage 160 includes a pilot paddle member 162. In the depicted embodiment, the leading paddle member 162 is connected to the shaft 132 by a pair of arms 164, the pair of arms 164 being disposed between and alongside the arms 143 of the fixed paddle 141. Leading paddle member 162 includes a paddle surface 166, paddle surface 166 engaging toner in reservoir 104 as discussed in more detail below. In the depicted example embodiment, paddle surface 166 is substantially planar and perpendicular to the direction of motion of sensing linkage 160 to allow paddle surface 166 to impact toner in reservoir 104.

Sensing linkage 160 also includes one or more permanent magnets 168. Magnets 168 are mounted on one or more magnet supports 170 of sensing linkage 160, and magnets 168 are disposed in close proximity to, but not in contact with, the inner surface of housing 102. In this manner, magnet 168 is disposed in close proximity to the inner surface of housing 102, but the inner surface of housing 102 does not obstruct the movement of sensing linkage 160. In the depicted example embodiment, the magnet support 170 is connected to the shaft 132 by a pair of arms 172, the pair of arms 172 being disposed between and alongside the arms 143 of the fixed paddle 141. Arm 172 is connected to arm 164. In this embodiment, in the position depicted in fig. 6, arm 172 extends from shaft 132 toward top 106. Of course, the position of the arm 172 changes as the shaft 132 rotates. In this embodiment, magnet support 170 is relatively thin in a radial dimension and extends circumferentially between the distal ends of arms 172 along the rotational path of magnet 168 relative to shaft 132 to minimize drag on magnet support 170 as magnet support 170 passes toner in reservoir 104. In the operational rotational direction a of shaft 132, pilot paddle member 162 is disposed forward (e.g., through less than 180 degrees) of magnet 150, while magnet 150 is disposed forward (e.g., through less than 180 degrees) of magnet 168.

In the depicted example embodiment, two

magnets

168a, 168b are mounted on a magnet support 170; however, as discussed below, one magnet 168 or more than two magnets 168 may be used as desired. The

magnets

168a, 168b are substantially radially and axially aligned with each other relative to the shaft 132 and are circumferentially spaced apart. The magnets 168 are also substantially radially and axially aligned with the magnets 150 relative to the shaft 132, and are circumferentially spaced apart. In one embodiment, the magnet support 170 comprises a non-magnetic material and the magnet 168 is held by a friction fit within one or more recesses in the magnetic support 170. Magnet 168 may also be attached to magnet support 170 using adhesives or fasteners so long as magnet 168 does not become disengaged from magnet support 170 during operation of toner cartridge 100. As discussed above, the magnet 168 may be any suitable size and shape and comprise any suitable material. The magnet support 170 may take many different forms, including arms, tabs, linkages, cross members, and the like.

In certain embodiments, sensing linkage 160 is biased in the operational rotational direction toward the forward rotational stop by one or more biasing members. In the depicted example embodiment, the sensing linkage 160 is biased by an extension spring 176 connected at one end to the arm 172 of the magnet support 170 and at the other end to the arm 143 of the fixed paddle 141. However, any suitable biasing member may be used, as desired. For example, in another embodiment, a torsion spring biases sensing linkage 160 in an operational rotational direction. In another embodiment, the compression spring is connected at one end to arm 164 of pilot paddle member 162 and at the other end to arm 143 of fixed paddle 141. In another embodiment, sensing linkage 160 is free to descend by gravity toward its forward rotational stop as sensing linkage 160 rotates through the uppermost point of its rotational path. In the depicted example embodiment, the forward rotation stop comprises a stop 178, the stop 178 extending axially from a side of one or both arms 172 of the magnet support 170. The stop 178 is arcuate and includes a pilot surface 180, the pilot surface 180 contacting the arm 143 of the fixed paddle 141 to limit movement of the sensing linkage 160 relative to the magnet 150 in the operational rotational direction. In the depicted example embodiment, the rearward rotation stop comprises tail 182 of pilot paddle member 162. Tail 182 of pilot paddle member 162 contacts pilot portion 184 of cross member 145 to limit movement of sensing linkage 160 relative to magnet 150 in a direction relative to the operational rotational direction. It will be appreciated that the forward and rearward rotation stops may take other forms as desired.

Fig. 7A-7C depict the operation of

magnets

150 and 168 at various toner levels. Fig. 7A-7C depict a clock face in phantom along the rotational path of shaft 132 and paddle assembly 140 to facilitate explanation of the operation of

magnets

150 and 168. As discussed in more detail below, the magnetic sensor 190 is configured to detect movement of the

magnets

150 and 168 during rotation of the shaft 132 in order to determine the amount of toner remaining in the reservoir 104. In one embodiment, magnetic sensor 190 is mounted on housing 102 of toner cartridge 100. In this embodiment, magnetic sensor 190 is in electronic communication with processing circuitry 45 of toner cartridge 100 so that information from magnetic sensor 190 can be transmitted to controller 28 of image forming device 22. In another embodiment, magnetic sensor 190 is disposed on a portion of image forming device 22 adjacent to housing 102 when toner cartridge 100 is installed in image forming device 22. In this embodiment, the magnetic sensor 190 is in electronic communication with the controller 28. In the depicted example embodiment, the magnetic sensor 190 is disposed adjacent to the top 106, or on the top 106. In other embodiments, the magnetic sensor 190 is disposed adjacent to or on the bottom 117, the front wall 114, the back wall 116, or the

side wall

110 or 112. In those embodiments in which magnetic sensor 190 is disposed adjacent to or on top 106, bottom 117, front wall 114 or rear wall 116,

magnets

150 and 168 are disposed adjacent to the inner surface of top 106, bottom 117, front wall 114 or rear wall 116 as shaft 132 rotates, such as at the radial ends of fixed paddle 141 and sensing linkage 160. In those embodiments in which magnetic sensor 190 is disposed adjacent to or on

sidewall

110 or 112,

magnets

150 and 168 are disposed adjacent to the inner surface of

sidewall

110 or 112, such as at the axial ends of fixed paddle 141 and sensing linkage 160. The magnetic sensor 190 may be any suitable device capable of detecting the presence or absence of a magnetic field. For example, the magnetic sensor 190 may be a hall effect sensor, which is a transducer that changes its electrical output in response to a magnetic field. In the depicted example embodiment, the magnetic sensor 190 is disposed outside of the reservoir 104 at about a "12 o' clock" position relative to the paddle assembly 140.

As the shaft 132 rotates, the movement of the sensing linkage 160 and the magnet 168 relative to the magnet 150 may be used to determine the amount of toner remaining in the reservoir 104. As the shaft 132 rotates, in the depicted embodiment, the fixed paddle 141 rotates with the shaft 132 such that the magnet 150 passes the magnetic sensor 190 at the same point during each revolution of the shaft 132. On the other hand, the movement of the sensing linkage 160 between its forward and rearward rotational stops, which is freely rotatable relative to the shaft 132, depends on the amount of toner 105 present in the reservoir 104. Thus, during the revolution of shaft 132, magnet 168 passes magnetic sensor 190 at different points depending on the toner level in reservoir 104. Thus, as the magnet 150 and magnet 168 pass the magnetic sensor 190, the change in the angular separation or offset between the magnet 150, which serves as a reference point, and the magnet 168, which provides a sensing point, can be used to determine the amount of toner remaining in the reservoir 104. In an alternative embodiment, the linkage connecting magnet 150 to shaft 132, for example fixed paddle 141, is movable to some extent independently of shaft 132; however, it is preferred that the magnet 150 pass the magnetic sensor 190 at the same position relative to the shaft 132 during each revolution of the shaft 132 so that the position of the magnet 168 can be consistently evaluated relative to the position of the magnet 150.

When the toner reservoir 104 is sufficiently full, toner 105 present in reservoir 104 prevents sensing linkage 160 from advancing forward of its rearward rotational stop. Instead, as shaft 132 rotates, sensing linkage 160 is pushed by fixed paddle 141 through the path of its rotation. Thus, when toner reservoir 104 is quite full, the amount of rotation of shaft 132 between magnet 150 passing magnetic sensor 190 and

magnets

168a, 168b on sensing linkage 160 passing magnetic sensor 190 is at its maximum. In other words, because sensing linkage 160 rotates the stop rearward thereof, the angular separation from magnet 168a to magnet 150 when magnet 168a reaches magnetic sensor 190 and the angular separation from magnet 168b to magnet 150 when magnet 168b reaches magnetic sensor 190 are at their maximum limits.

When the toner level in reservoir 104 decreases as shown in fig. 7A, sensing linkage 160 is set forward from its rearward rotational stop as leading paddle 162 rotates forward from the "12 o' clock" position. Leading paddle member 162 advances forward of the rearward rotational stop of sensing linkage 160 until paddle surface 166 contacts toner 105, which stops the advancement of sensing linkage 160. In one embodiment in which paddle assembly 140 includes blades 148, blades 148 are not present on cross member 144 connected to set 142b of arms 142 along a portion of the axial direction of shaft 132 traversed by leading paddle member 162, such that toner 105 is not disturbed just before paddle surface 166 contacts toner 105 after leading paddle member 162 is rotated forward from the "12 o' clock" position. At higher toner levels, leading paddle member 162 is stopped by toner 105 before

magnets

168a, 168b reach magnetic sensor 190 so that the amount of rotation of shaft 132 between magnet 150 passing through magnetic sensor 190 and

magnets

168a, 168b passing through magnetic sensor 190 is maintained at its maximum. Sensing linkage 160 then remains substantially stationary on (or slightly below) the top of toner 105 until fixed paddle 141 catches up with leading paddle member 162 at the rearward rotational stop of sensing linkage 160 and fixed paddle 141 resumes pushing sensing linkage 160.

Referring to fig. 7B, as the toner level in reservoir 104 continues to decrease, magnet 168a is detected by magnetic sensor 190 at the point where leading paddle member 162 reaches toner 105. Accordingly, the amount of rotation of the shaft 132 between the magnet 150 passing through the magnetic sensor 190 and the magnet 168a passing through the magnetic sensor 190 is reduced. Sensing linkage 160 then remains substantially stationary on (or slightly below) the top of toner 105 with magnet 168a within the sensing window of magnetic sensor 190 until fixed paddle 141 catches up with leading paddle member 162 and resumes pushing sensing linkage 160. Thus, before magnet 168b reaches magnetic sensor 190, pilot paddle member 162 is stopped by toner 105 so that the amount of rotation of shaft 132 between magnet 150 passing through magnetic sensor 190 and magnet 168b passing through magnetic sensor 190 is maintained at its maximum.

Referring to fig. 7C, when the toner level in reservoir 104 is reduced even further, at the point where leading paddle member 162 reaches toner 105, magnet 168a has passed magnetic sensor 190, and magnet 168b is detected by magnetic sensor 190. Thus, the amount of rotation of the shaft 132 between the magnet 150 passing through the magnetic sensor 190 and the

magnets

168a and 168b passing through the magnetic sensor 190 is reduced relative to its maximum value. Thus, it will be appreciated that the movement of the

magnets

168a, 168b relative to the movement of the magnet 150 relates to the amount of toner 105 remaining in the reservoir 104.

Fig. 8 is a graph of the angular separation between magnet 150 and the point at which

magnets

168a and 168b pass magnetic sensor 190 versus the amount of toner 105 remaining in reservoir 104, according to an example embodiment. Specifically, line a is the angular separation between magnet 150 and magnet 168a relative to the amount of toner 105 remaining in reservoir 104, and line B is the angular separation between magnet 150 and magnet 168B relative to the amount of toner 105 remaining in reservoir 104. As shown in fig. 8, at higher toner levels, the amount of rotation of shaft 132 between magnet 150 passing through magnetic sensor 190 and

magnets

168a, 168b passing through magnetic sensor 190 is maintained at its maximum. In this example, when approximately 450 grams of toner 105 is maintained in reservoir 104, leading paddle member 162 advances in front of the rearward rotational stop of sensing linkage 160 until paddle surface 166 contacts toner 105 at a point where magnet 168a is within the sensing window of magnetic sensor 190. Thus, the amount of rotation of the shaft 132 between the magnet 150 passing through the magnetic sensor 190 and the magnet 168a passing through the magnetic sensor 190 is reduced, while the amount of rotation of the shaft 132 between the magnet 150 passing through the magnetic sensor 190 and the magnet 168b passing through the magnetic sensor 190 is maintained at its maximum. In this example, when approximately 300 grams of toner 105 is maintained in reservoir 104, leading paddle member 162 advances in front of the rearward rotational stop of sensing linkage 160 until paddle surface 166 contacts toner 105 at a point where magnet 168b is within the sensing window of magnetic sensor 190. Thus, the amount of rotation of the shaft 132 between the magnet 150 passing through the magnetic sensor 190 and the

magnets

168a and 168b passing through the magnetic sensor 190 is reduced relative to its maximum value.

In some embodiments, the poles of each

magnet

150, 168 are directed to the location of the magnetic sensor 190 in order to cause the

magnets

150, 168 to be detected by the magnetic sensor 190. For example, where the magnetic sensor 190 is positioned near the top 106 or on the top 106, the poles of each

magnet

150, 168 point radially outward away from the shaft 132 and toward the top 106, bottom 117, front wall 114, and rear wall 116 as the shaft 132 rotates. The magnetic sensor 190 may be configured to detect one or both of a north pole and a south pole. When the magnetic sensor 190 detects one of the north pole and the south pole, the

magnets

150, 168 are arranged such that the detected pole is directed toward the magnetic sensor 190.

Where the magnetic sensor 190 is configured to detect both north and south poles, in some embodiments, a first pole of the magnet 150 is directed toward the magnetic sensor 190 and an opposite pole of the magnet(s) 168 is directed toward the magnetic sensor 190. For example, fig. 6 shows north poles of magnets 150 pointing radially outward away from shaft 132 and toward top 106, bottom 117, front wall 114, and rear wall 116 as shaft 132 rotates, and south poles of

magnets

168a and 168b pointing radially outward away from shaft 132 and toward top 106, bottom 117, front wall 114, and rear wall 116 as shaft 132 rotates. Directing the opposite poles of the magnet 150 and the magnet(s) 168 toward the magnetic sensor 190 allows the controller 28 (or another processor) to immediately distinguish between the magnet 150 and the magnet(s) 168 based on the detected polarity. Otherwise, in the case where the magnet 150 and magnet(s) 168 have the same orientation relative to the magnetic sensor 190, the processor must infer whether the magnet detected by the magnetic sensor 190 is the magnet 150 or the magnet(s) 168 by comparing the amount of rotation of the shaft 132 that occurs between detections of successive magnets to a known range of possible angular positions of the magnet(s) 168 relative to the magnet 150 (and a known angular separation between the

magnets

168a, 168b, etc., if more than one magnet 168 is present). The range of angular positions of magnet(s) 168 relative to magnet 150 is defined by sensing the positions of the forward and rearward rotation stops of linkage 160. Thus, where the magnet 150 and the magnet(s) 168 have the same orientation relative to the magnetic sensor 190, the detection of at least two magnets needs to be before the magnet 150 can be distinguished from the magnet(s) 168.

Information from the magnetic sensor 190 may be used by the controller 28 or a processor in communication with the controller 28 (e.g., a processor of the processing circuitry 45) to help determine the amount of toner 105 remaining in the reservoir 104. In one embodiment, the initial amount of toner 105 in reservoir 104 is recorded in a memory associated with processing circuitry 45 at the time that toner cartridge 100 is filled. Thus, the processor that determines the amount of toner 105 remaining in reservoir 104 can determine the initial toner level in reservoir 104 when toner cartridge 100 is installed in image forming device 22. Alternatively, each toner cartridge 100 for a particular type of image forming device 22 may be filled with the same amount of toner, so that the initial toner level in reservoir 104 used by the processor may be a fixed value for all toner cartridges 100. When toner is loaded from the toner cartridge to imaging unit 200 based on one or more operating conditions of image forming device 22 and/or toner cartridge 100, the processor then estimates the amount of toner remaining in reservoir 104. In one embodiment, when shaft 132 and auger 136 are rotated to transfer toner from toner cartridge 100 to imaging unit 200, the amount of toner 105 remaining in reservoir 104 is approximated based on an empirically derived fill rate of toner 105 from toner reservoir 104. In this embodiment, the estimation of the amount of residual toner 105 is reduced according to the amount of rotation of the drive motor of the image forming apparatus 22, which provides the rotational force determined by the controller 28 to the main interface gear 130. In another embodiment, when toner cartridge 100 is installed in image forming device 22, the estimate of the amount of toner 105 remaining is reduced according to the number of printable elements (pixels) printed with toner colors contained in toner cartridge 100. In another embodiment, the estimate of the amount of toner 105 remaining is decreased according to the number of printed pages.

In situations where the amount of rotation of shaft 132 occurring between magnet 150 passing magnetic sensor 190 and each magnet 168 passing magnetic sensor 190 is reduced, the amount of toner 105 remaining in reservoir 104 may be determined empirically for a particular toner cartridge design. Thus, each time the amount of rotation of shaft 132 between detection of magnet 150 and detection of one of magnets 168 is reduced from its maximum value, the processor may adjust the estimate of the amount of toner remaining in reservoir 104 based on the empirically determined amount of toner associated with the reduction in the amount of rotation of shaft 132 between magnet 150 passing through magnetic sensor 190 and the corresponding magnet 168 passing through magnetic sensor 190.

For example, the toner level in reservoir 104 may be approximated by an estimate that starts from the initial amount of toner 105 supplied in reservoir 104 and decreases the amount of toner 105 remaining in reservoir 104 as toner 105 is consumed from reservoir 104. As discussed above, the estimate of remaining toner may be reduced based on one or more conditions such as the amount of rotation of the drive motor, the primary interface gear 130 or shaft 132, the number of pixels printed, the number of pages printed, and the like. The estimated amount of toner remaining may be recalculated based on its maximum value as the amount of rotation of shaft 132 as determined by controller 28 between magnet 150 through magnetic sensor 190 and magnet 168a through sensing linkage 160 of magnetic sensor 190 decreases. In one embodiment, this includes replacing the estimate of the amount of toner remaining with an empirical value related to a reduction in the amount of rotation of shaft 132 between magnet 150 passing magnetic sensor 190 and magnet 168a passing magnetic sensor 190. In another embodiment, recalculating the current estimate for the amount of toner remaining and the empirical value associated with the decrease in the amount of rotation of shaft 132 between magnet 150 passing through magnetic sensor 190 and magnet 168a passing through magnetic sensor 190 are both weighted. The modified estimate of the amount of toner 105 remaining in reservoir 104 is then reduced as toner 105 is consumed from reservoir 104 using one or more conditions as discussed above. When the amount of rotation of shaft 132 between magnet 150 through magnetic sensor 190 and magnet 168b through sensing linkage 160 of magnetic sensor 190, as determined by controller 28, decreases from its maximum value, the estimated amount of toner remaining may again be recalculated. As discussed above, this may include an estimate recalculation that weights both the estimate instead of or for the current estimate of the amount of toner remaining and the empirical value related to the reduction in the amount of rotation of shaft 132 between magnet 150 through magnetic sensor 190 and magnet 168b through magnetic sensor 190. This process may be repeated until reservoir 104 runs out of toner 105. In one embodiment, a current estimate of the amount of toner 105 remaining in reservoir 104 is stored in a memory associated with processing circuitry 45 of toner cartridge 100 such that if toner cartridge 100 is removed from one image forming device 22 and installed in another image forming device 22, then the estimate moves with toner cartridge 100.

In this manner, the detection of the movement of magnet 168 relative to the movement of magnet 150 may serve as a correction for the estimation of the toner level in reservoir 104 according to other conditions, such as empirically derived toner fill rate or number of printed pixels or pages, as discussed above, to account for variations and correct for possible errors in such estimation. For example, an estimate of toner level based on conditions such as empirically derived toner fill rate or number of printed pixels or pages may drift away from the actual amount of toner 105 remaining in reservoir 104 during the life of the toner cartridge 100, i.e., the difference between the estimate of toner level and the actual toner level may tend to increase over the life of the toner cartridge 100. Recalculating the estimate of the amount of toner 105 remaining from the movement of magnet 168 relative to the movement of magnet 150 helps to correct this offset, thereby providing a more accurate estimate of the amount of toner 105 remaining in reservoir 104.

It will be appreciated that the sensing linkage 160 may contain any suitable number of magnets 168 as desired depending on how many recalculations of the amount of toner remaining are desired. For example, in situations where more frequent recalculations of estimated toner levels are desired, the sensing linkage 160 may include more than two magnets 168 circumferentially spaced from one another. Alternatively, in situations where recalculation of the estimated toner level is desired only once (e.g., near a point where the reservoir 104 is nearly empty), the sensing linkage 160 may include a single magnet 168. The position of magnet 168 relative to pilot paddle member 162 may be selected so as to sense a particular toner level desired (e.g., 300 grams of toner remaining, 100 grams of toner remaining, etc.). Also, in the case where shaft 132 rotates at a fixed speed during operation of toner cartridge 100, the time difference between detection by magnet 150 and magnet 168 by magnetic sensor 190 may be used instead of using the amount of rotation of shaft 132. In this embodiment, time differences greater than a predetermined threshold between detection of the magnet 150 and one or more magnets 168 may be ignored by the processor to account for the shaft 132 stopping between print jobs.

Sensing linkage 160 is not limited to the shape and configuration shown in FIG. 6 and may take many shapes and sizes as desired. For example, fig. 9A depicts a sensing linkage 1160 including a magnet support 1170 in the form of radially extending arms 1172. The magnet support 1170 is relatively thin in the axial direction and includes magnets 1168 that are radially and axially aligned and circumferentially spaced from each other. In this embodiment, magnet 1168 is disposed in a location at an axial end of sensing linkage 1160 that is detected by a magnetic sensor adjacent to sidewall 110 or 112, or on

sidewall

110 or 112. Fig. 9B depicts a sensing linkage 2160 like the sensing linkage 160 discussed above with respect to fig. 6, including a pair of arms 2172 connecting the magnet support 2170 to the shaft 132. Sensing linkage 2160 differs from sensing linkage 160 in that magnet support 2170 and arm 2172 further extend in a circumferential dimension to accommodate additional magnets 2168. Fig. 9C depicts sensing linkage 3160, which includes a series of circumferentially spaced and axially aligned radial arms 3172, which respectively serve as magnet supports 3170. In this embodiment, each magnet support 3170 provides a respective magnet 3168 for detection by a magnetic sensor disposed adjacent to or on a

side wall

110 or 112.

Leading paddle member 162 having paddle surface 166 that engages toner in reservoir 104 may also take on many shapes and sizes as desired. For example, in one embodiment, paddle surface 166 is angled relative to the direction of motion of sensing linkage 160. For example, paddle surface 166 may be V-shaped and have a front face forming a portion with a concave surface having a V-shaped profile. In another embodiment, paddle surface 166 includes a comb portion having a series of teeth that are axially spaced from each other to reduce friction between the sensing linkage and toner. The surface area of the paddle surface 166 may also vary as desired. Further, in some embodiments, the pilot paddle member 162 includes a permanent magnet 186 positioned for detection by a magnetic sensor 190 as shown in fig. 6. The change in the angular separation or offset between magnet 150 and magnet 186 as they pass magnetic sensor 190 may be used to further detect the movement of sensing linkage 160 relative to magnet 150 to estimate the amount of toner remaining in reservoir 104. In those embodiments in which the poles of the magnet 150 are oriented opposite to the poles of the magnet(s) 168, the poles of the magnet 186 may have the same orientation as the magnet(s) 168. For example, fig. 6 shows the south poles of magnets 186 directed radially outward away from shaft 132, as

magnets

168a, 168 b.

The amount of toner remaining in the reservoir may then be determined by sensing relative movement between the sensing linkage and the fixed linkage within the reservoir. Because the sensing linkage and fixed linkage movement are detectable by sensors external to the reservoir 104, the sensing linkage and fixed linkage may be provided without electrical or mechanical connection to the exterior of the housing 102 (rather than the shaft 132). This avoids the need for additional, potentially leak-prone connections that seal into the reservoir 104. Locating the magnetic sensor 190 outside of the reservoir 104 reduces the risk of toner contamination that could damage the sensor. Magnetic sensor 190 may also be used to detect the installation of toner cartridge 100 in the image forming device and to confirm whether shaft 132 is rotating properly, thereby eliminating the need for additional sensors to perform these functions.

Although the example embodiment depicted in fig. 7A-7C shows the magnetic sensor 190 disposed at approximately "12 o' clock" with respect to the paddle assembly 140, the magnetic sensor 190 may be disposed elsewhere on the rotational path of the paddle assembly 140 as desired. For example, by changing the position of magnet 150 and magnet 168 relative to pilot paddle member 162 by 180 degrees, magnetic sensor 190 may be disposed at approximately a "6 o' clock" position relative to paddle assembly 140.

While the example embodiments discussed above utilize a sensing linkage and a fixed linkage in the reservoir of the toner cartridge, it will be appreciated that a sensing linkage and a fixed linkage, both having magnets, may be used to determine the toner level in any toner-storing reservoir or cartridge in image forming device 22 (e.g., the reservoir of the imaging unit or a storage area for waste toner). Also, while the example embodiments discussed above discuss a system for determining toner levels, it will be appreciated that the systems and methods discussed herein may be used to determine levels of particulate materials other than toner, such as grains, seeds, flour, sugar, salt, and the like.

Although the examples discuss sensing a magnet with a magnetic sensor, in another embodiment, an inductive sensor, such as an eddy current sensor, or a capacitive sensor is used instead of a magnetic sensor. In this embodiment, the fixed linkage and the sensing linkage comprise conductive elements that are detectable by inductive or capacitive sensors. As discussed above with respect to

magnets

150 and 168, metallic elements may be attached to the fixed linkage and sensing linkage by friction fit, adhesives, fasteners, etc., or portions of the fixed linkage and sensing linkage may comprise metallic materials.

Fig. 10 illustrates another example embodiment of a paddle assembly 4140. In this embodiment, the toner cartridge includes a paddle 4141 that is fixed to the shaft 4132 such that the paddle 4141 rotates with the shaft 4132. The paddle 4141 includes a plurality of permanent magnets 4168 mounted on one or more magnet supports 4170. As discussed above, magnet 4168 is disposed in close proximity to but not in contact with the inner surface of the housing of the toner cartridge. In the example embodiment depicted, the magnet support 4170 is connected to the shaft 4132 by a pair of arms 4172. In the depicted example embodiment, two

magnets

4168a, 4168b are mounted on the magnet support 4170; however, more than two magnets 4168 may be used as desired. The

magnets

4168a, 4168b are substantially radially and axially aligned with and circumferentially spaced relative to the shaft 4132. The magnet 4168 may be oriented, shaped, and mounted to the shaft 4132 in various ways as discussed above. In this embodiment, the magnetic sensor 190 detects the magnet 4168 as the shaft 4132 rotates. In this manner, magnetic sensor 190 can be used to detect the presence or absence of a toner cartridge in the image forming device and confirm whether shaft 4132 is rotating properly, thereby eliminating the need for additional sensors to perform these functions. The magnetic sensor 190 may also be used to determine the rotational speed of the shaft 4132 by measuring the time difference between the detection of the magnet 4168a and the detection of the magnet 4168b as the shaft 4132 rotates. The magnetic sensor 190 may also be used to determine the amount of rotation of the shaft 4132 by counting the passes of the magnet 4168.

The above description illustrates various aspects of the present disclosure. It is not intended to be exhaustive. Rather, it was chosen to illustrate the principles of the present disclosure and its practical application to enable one of ordinary skill in the art to utilize the present disclosure, including various modifications thereof. All such modifications and variations are considered to be within the scope of the present disclosure as determined by the appended claims. Rather obvious modifications include combinations of one or more features of various embodiments with features of other embodiments.

Aspects of the disclosure can be implemented in one or more of the following embodiments.

1) A replaceable unit for an electrophotographic image forming apparatus, comprising:

a housing having a reservoir for storing toner;

a rotatable shaft disposed within the reservoir and having an axis of rotation; and

a first magnet and a second magnet connected to the shaft and rotatable about the rotation axis in response to rotation of the shaft, the first magnet and the second magnet being detectable by a magnetic sensor when the replaceable unit is installed in the image forming apparatus, a polarity of the first magnet being oriented opposite to a polarity of the second magnet with respect to the shaft,

wherein an amount of angular offset between the first magnet and the second magnet varies depending on an amount of toner in the reservoir.

2) The replaceable unit of claim 1), wherein one of the north and south poles of the first magnet is directed outwardly away from the shaft and the other of the north and south poles of the second magnet is directed outwardly away from the shaft.

3) The replaceable unit of claim 1), wherein the first magnet and the second magnet are substantially axially aligned about the axis of rotation.

4) The replaceable unit of claim 1), wherein the first magnet and the second magnet are substantially radially aligned about the axis of rotation.

5) The replaceable unit of claim 1), further comprising a first linkage rotatable with the shaft and rotatable independently of the shaft between a forward rotational stop and a rearward rotational stop, the second magnet being mounted on the first linkage.

6) The replaceable unit of claim 5), further comprising a second linkage fixed to rotate with the shaft, the first magnet being mounted on the second linkage.

7) The replaceable unit of claim 5), wherein the first linkage has a paddle member that leads the first magnet in the operational rotational direction of the shaft, and the second magnet lags the first magnet in the operational rotational direction of the shaft.

8) The replaceable unit of claim 7), wherein the paddle member includes a third magnet.

9) The replaceable unit of claim 5), wherein the first linkage is biased in an operational rotational direction of the shaft toward the forward rotation stop by a biasing member.

10) A replaceable unit for an electrophotographic image forming apparatus, comprising:

a housing having a reservoir for storing toner;

a first magnet and a second magnet connected to the shaft and rotatable about the axis of rotation in response to rotation of the shaft, the first magnet and the second magnet passing through a vicinity of at least a portion of an inner wall of a housing forming the reservoir during rotation of the first magnet and the second magnet, a first pole of the first magnet pointing outward away from the shaft and a second pole of the second magnet pointing outward away from the shaft, the first pole having a polarity opposite to a polarity of the second pole,

11) The replaceable unit of claim 10), wherein the first magnet and the second magnet are substantially axially aligned about the axis of rotation.

12) The replaceable unit of claim 10), wherein the first magnet and the second magnet are substantially radially aligned about the axis of rotation.

13) The replaceable unit of claim 10), further comprising a first linkage rotatable with the shaft and rotatable independently of the shaft between a forward rotational stop and a rearward rotational stop, the second magnet being mounted on the first linkage.

14) The replaceable unit of claim 13), further comprising a second linkage fixed to rotate with the shaft, the first magnet being mounted on the second linkage.

15) The replaceable unit of claim 13), wherein the first linkage has a paddle member that leads the first magnet in the operational rotational direction of the shaft, and the second magnet lags the first magnet in the operational rotational direction of the shaft.

16) The replaceable unit of claim 15), wherein the paddle member includes a third magnet that passes near at least a portion of the inner wall of the housing forming the reservoir during rotation of the shaft.

17) The replaceable unit of claim 13), wherein the first linkage is biased in an operational rotational direction of the shaft toward the forward rotation stop by a biasing member.

Claims

1. A replaceable unit for an electrophotographic image forming apparatus, comprising:

a housing having a reservoir for storing toner;

a rotatable shaft disposed within the reservoir and having an axis of rotation;

a linkage rotatable with the rotatable shaft about the axis of rotation, the linkage having a first magnet;

a paddle member that leads the first magnet in an operational rotational direction of the rotatable shaft such that the paddle member is positioned closer to a leading end of the first magnet than to a trailing end of the first magnet in the operational rotational direction of the rotatable shaft, the paddle member includes a second magnet that leads the first magnet in the operational rotational direction of the rotatable shaft such that the second magnet is positioned closer to a front end of the first magnet than to a rear end of the first magnet in the operational rotational direction of the rotatable shaft, the paddle member is rotatable independently of the rotatable shaft between a forward rotation stop and a rearward rotation stop, such that the amount of angular offset between the first and second magnets varies as a function of the rotational position of the paddle member relative to the forward and rearward rotation stops.

2. The replaceable unit of claim 1, wherein the paddle member is biased by a biasing member in the operational rotational direction of the rotatable shaft toward the forward rotation stop.

3. The replaceable unit of claim 1, wherein the second magnet is angularly spaced forward from the first magnet relative to the operational rotational direction of the rotatable shaft when the paddle member is located at the rearward rotation stop.

4. The replaceable unit of claim 1, wherein the first magnet and the second magnet are substantially axially aligned about the axis of rotation.

5. The replaceable unit of claim 1, wherein the first magnet and the second magnet are substantially radially aligned about the axis of rotation.

6. The replaceable unit of claim 1, wherein the first and second magnets pass near a point on an inner wall of the housing forming the reservoir once per rotation of the rotatable shaft when the replaceable unit is installed in the image forming device for detection by a magnetic sensor.

7. The replaceable unit of claim 1, wherein the linkage is fixed for rotation with the rotatable shaft.

8. The replaceable unit of claim 1, wherein the polarity of the first magnet is oriented opposite the polarity of the second magnet relative to the rotatable shaft.

9. A replaceable unit for an electrophotographic image forming apparatus, comprising:

a housing having a reservoir for storing toner;

a rotatable shaft disposed within the reservoir and having an axis of rotation;

a first linkage rotatable with the rotatable shaft about the axis of rotation, the first linkage having a first magnet;

a second coupling rotatable about the axis of rotation in response to rotation of the rotatable shaft, the second coupling having a second magnet that precedes the first magnet in an operational rotational direction of the rotatable shaft such that the second magnet is positioned closer to a front end of the first magnet than to a rear end of the first magnet in the operational rotational direction of the rotatable shaft, the second coupling being rotatable independently of the rotatable shaft between a forward rotational stop and a rearward rotational stop such that an amount of angular offset between the first magnet and the second magnet varies as a function of a rotational position of the second coupling relative to the forward rotational stop and the rearward rotational stop, the second magnet being rotatable relative to the operational rotational direction of the rotatable shaft and the rotational stop when the second coupling is at the rearward rotational stop The first magnet is angularly spaced forward.

10. The replaceable unit of claim 9, wherein the second linkage includes a paddle member that precedes the first magnet in the operational rotational direction of the rotatable shaft, and the second magnet is positioned on the paddle member.

11. The replaceable unit of claim 9, wherein the second linkage is biased by a biasing member in the operational rotational direction of the rotatable shaft toward the forward rotation stop.

12. The replaceable unit of claim 9, wherein the first magnet and the second magnet are substantially axially aligned about the axis of rotation.

13. The replaceable unit of claim 9, wherein the first magnet and the second magnet are substantially radially aligned about the axis of rotation.

14. The replaceable unit of claim 9, wherein the first and second magnets pass near a point on an inner wall of the housing forming the reservoir once per rotation of the rotatable shaft when the replaceable unit is installed in the image forming device for detection by a magnetic sensor.

15. The replaceable unit of claim 9, wherein the first linkage is fixed for rotation with the rotatable shaft.

16. The replaceable unit of claim 9, wherein the polarity of the first magnet is oriented opposite the polarity of the second magnet relative to the rotatable shaft.

17. A replaceable unit for an electrophotographic image forming apparatus, comprising:

a housing having a reservoir for storing toner;

a rotatable shaft disposed within the reservoir and having an axis of rotation;

a second linkage rotatable about the axis of rotation in response to rotation of the rotatable shaft, the second linkage having a second magnet that leads the first magnet in the operational rotational direction of the rotatable shaft such that the second magnet is positioned closer to the front end of the first magnet than to the rear end of the first magnet in the operational rotational direction of the rotatable shaft, the second linkage is rotatable independently of the rotatable shaft between a forward rotation stop and a rearward rotation stop, such that the amount of angular offset between the first magnet and the second magnet varies depending on the rotational position of the second linkage relative to the forward rotation stop and the rearward rotation stop, the second linkage is biased in the operational rotational direction of the rotatable shaft toward the forward rotation stop by a biasing member.

18. The replaceable unit of claim 17, wherein the second linkage includes a paddle member that precedes the first magnet in an operational rotational direction of the rotatable shaft, and the second magnet is positioned on the paddle member.

19. The replaceable unit of claim 17, wherein the first magnet and the second magnet are substantially axially aligned about the axis of rotation.

20. The replaceable unit of claim 17, wherein the first magnet and the second magnet are substantially radially aligned about the axis of rotation.

21. The replaceable unit of claim 17, wherein the first and second magnets pass near a point on an inner wall of the housing forming the reservoir once per rotation of the rotatable shaft when the replaceable unit is installed in the image forming device for detection by a magnetic sensor.

22. The replaceable unit of claim 17, wherein the first linkage is fixed for rotation with the rotatable shaft.

23. The replaceable unit of claim 17, wherein the polarity of the first magnet is oriented opposite the polarity of the second magnet relative to the rotatable shaft.