Patent Publication Number: US-9417603-B2

Title: Toner cartridge having positional control features

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This patent application is a continuation application of U.S. patent application Ser. No. 13/340,911, filed Dec. 30, 2011, entitled “Toner Cartridge having Positional Control Features.” This patent application is related to U.S. patent application Ser. No. 13/340,935, filed Dec. 30, 2011, entitled “Toner Cartridge for Use in an Image Forming Device,” which is assigned to the assignee of the present application. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates generally to toner cartridges used in electrophotographic image forming devices and, more particularly, to a toner cartridge having positional control features. 
     2. Description of the Related Art 
     In order to reduce the premature replacement of components traditionally housed within a toner cartridge for an image forming device, toner cartridge manufacturers have begun to separate components having a longer life from those having a shorter life into separate replaceable units. Relatively longer life components such as a developer roll, a toner adder roll, a doctor blade and a photoconductive drum are positioned in one replaceable unit (an “imaging unit”). The image forming device&#39;s toner supply, which is consumed relatively quickly in comparison with the components housed in the imaging unit, is provided in a reservoir in a separate replaceable unit in the form of a toner cartridge that mates with the imaging unit. In this configuration, the number of components housed in the toner cartridge is reduced in comparison with traditional toner cartridges. As a result, in systems utilizing a separate toner cartridge and imaging unit, the toner cartridge is often referred to as a “toner bottle” even though the toner cartridge is more complex than a mere bottle for holding toner. 
     To deliver toner from the toner cartridge to the imaging unit, an auger in the toner cartridge may be used to feed toner from an exit port on the toner cartridge into an entrance port on the imaging unit and into a second auger that disperses the toner within the imaging unit. As the toner is drawn out of the toner cartridge, it is augured through a shutter used for sealing the exit port of the toner cartridge when it is not inserted in the printer. 
     In devices utilizing a separate toner cartridge and imaging unit, it is important that the toner cartridge and imaging unit are precisely aligned relative to one another within the image forming device. For example, if the exit port on the toner cartridge is misaligned with the entrance port on the imaging unit, severe toner leakage may occur resulting in mechanical and print quality defects. The toner cartridge and imaging unit must also be rigidly held in place after they are installed in the image forming device in order to prevent their positional alignment from being disturbed during operation. The requirement for tight positional control must be balanced with the need to permit the user to easily load and unload the imaging unit and the toner cartridge into and out of the image forming device. Accordingly, it will be appreciated that a toner cartridge having positional control features that permit precise alignment of the cartridge while permitting various angles of insertion of the cartridge into the image forming device is desired. 
     SUMMARY 
     A toner cartridge for use in an image forming device according to one example embodiment includes a housing having a reservoir for containing toner therein. The housing has a front, a rear, a first side, a second side, a top and a bottom. The housing has an exit port on the front of the housing in fluid communication with the reservoir to permit toner from the reservoir to pass out of the housing. A first leg and a second leg each project from the bottom of the housing and extend primarily along a front-to-rear dimension of the housing to limit the side-to-side travel of the toner cartridge during insertion into the image forming device. A first alignment guide is positioned on the first side of the housing and a second alignment guide is positioned on the second side of the housing substantially parallel to the first alignment guide. Each alignment guide extends primarily along the front-to-rear dimension of the housing. The first alignment guide includes a pair of rounded contact points and the second alignment guide includes a rounded contact point. The rounded contact points of the first and second alignment guides are convex to the bottom and unobstructed from the bottom to control the vertical position of the toner cartridge in the image forming device. 
     A toner cartridge for use in an image forming device according to another example embodiment includes a housing having a reservoir for containing toner therein. The housing has a front, a rear, a first side, a second side, a top and a bottom. The housing has an exit port on the front of the housing in fluid communication with the reservoir to permit toner from the reservoir to pass out of the housing. A first leg and a second leg each project from the bottom of the housing and extend primarily along a front-to-rear dimension of the housing to limit the side-to-side travel of the toner cartridge during insertion into the image forming device. A first alignment guide is positioned on the first side of the housing and a second alignment guide is positioned on the second side of the housing substantially parallel to the first alignment guide. Each alignment guide extends primarily along the front-to-rear dimension of the housing. The first alignment guide includes a pair of rounded contact points and the second alignment guide includes a rounded contact point. The rounded contact points of the first and second alignment guides are convex to the bottom and unobstructed from the bottom. The rounded contact points of the first and second alignment guides collectively form three datum points defining a plane that controls the vertical position of the toner cartridge in the image forming device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of the various embodiments, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings. 
         FIG. 1  is a block diagram of an imaging system according to one example embodiment. 
         FIG. 2  is a perspective view of a toner cartridge and an imaging unit according to one example embodiment. 
         FIGS. 3 and 4  are additional perspective views of the toner cartridge shown in  FIG. 2 . 
         FIGS. 5 and 6  are exploded views of the toner cartridge shown in  FIG. 2  showing a reservoir for holding toner therein. 
         FIG. 7  is a top perspective view of the toner cartridge and imaging unit shown in  FIG. 2 . 
         FIG. 8  is a cross-sectional view of the toner cartridge and imaging unit taken along line  8 - 8  in  FIG. 7  with the toner cartridge advanced closer to the imaging unit. 
         FIG. 9  is a side elevation view of the toner cartridge shown in  FIG. 2  as it is loaded into an image forming device. 
         FIG. 10  is a side elevation view of the toner cartridge shown in  FIG. 2  in its final position in the image forming device. 
         FIG. 11  is a side elevation view of the toner cartridge shown in  FIG. 2  in its final position in the image forming device showing the engagement of various interface features. 
         FIGS. 12A-C  are sequential views of a first wing guide on the toner cartridge advancing in a corresponding insertion path in the image forming device according to one example embodiment. 
         FIGS. 13A-C  are sequential views of a second wing guide on the toner cartridge advancing in a corresponding insertion path in the image forming device according to one example embodiment. 
         FIGS. 14A-C  are sequential cross-sectional views of a leg of the toner cartridge taken along line  14 - 14  in  FIG. 2  as the toner cartridge is inserted into the image forming device according to one example embodiment. 
         FIG. 15  is a perspective view of a toner cartridge and an imaging unit according to a second example embodiment. 
         FIG. 16  is a top perspective view of the toner cartridge and imaging unit shown in  FIG. 15 . 
         FIG. 17  is a cross-sectional view of the toner cartridge and imaging unit taken along line  17 - 17  in  FIG. 16  with the toner cartridge advanced closer to the imaging unit. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and drawings illustrate embodiments sufficiently to enable those skilled in the art to practice the present invention. It is to be understood that the disclosure is not limited to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. For example, other embodiments may incorporate structural, chronological, electrical, process, and other changes. Examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of the application encompasses the appended claims and all available equivalents. The following description is, therefore, not to be taken in a limited sense and the scope of the present invention is defined by the appended claims. 
     Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. 
     Spatially relative terms such as “top”, “bottom”, “front”, “back”, “rear” and “side” “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are generally used in reference to the position of an element in its intended working position within an image forming device. Further, terms such as “first”, “second”, and the like, are used to describe various elements, regions, sections, etc. and are not intended to be limiting. The term “image” as used herein encompasses any printed or digital form of text, graphic, or combination thereof. Like terms refer to like elements throughout the description. 
     Referring now to the drawings and particularly to  FIG. 1 , there is shown a block diagram depiction of an imaging system  20  according to one example embodiment. Imaging system  20  includes an image forming device  22  and a computer  24 . Image forming device  22  communicates with computer  24  via a communications link  26 . As used herein, the term “communications link” generally refers to any structure that facilitates electronic communication between multiple components and may operate using wired or wireless technology and may include communications over the Internet. 
     In the example embodiment shown in  FIG. 1 , image forming device  22  is a multifunction machine (sometimes referred to as an all-in-one (AIO) device) that includes a controller  28 , a print engine  30 , a laser scan unit (LSU)  31 , an imaging unit  32 , a toner cartridge  35 , a user interface  36 , a media feed system  38 , a media input tray  39  and a scanner system  40 . Image forming device  22  may communicate with computer  24  via a standard communication protocol, such as for example, universal serial bus (USB), Ethernet or IEEE 802.xx. Image forming device  22  may be, for example, an electrophotographic printer/copier including an integrated scanner system  40  or a standalone electrophotographic printer. 
     Controller  28  includes a processor unit and associated memory  29  and may be formed as one or more Application Specific Integrated Circuits (ASICs). Memory  29  may be any volatile or non-volatile memory of combination thereof such as, for example, random access memory (RAM), read only memory (ROM), flash memory and/or non-volatile RAM (NVRAM). Alternatively, memory  29  may be in the form of a separate electronic memory (e.g., RAM, ROM, and/or NVRAM), a hard drive, a CD or DVD drive, or any memory device convenient for use with controller  28 . Controller  28  may be, for example, a combined printer and scanner controller. 
     In the example embodiment illustrated, controller  28  communicates with print engine  30  via a communications link  50 . Controller  28  communicates with imaging unit  32  and processing circuitry  44  thereon via a communications link  51 . Controller  28  communicates with toner cartridge  35  and processing circuitry  45  therein via a communications link  52 . Controller  28  communicates with media feed system  38  via a communications link  53 . Controller  28  communicates with scanner system  40  via a communications link  54 . User interface  36  is communicatively coupled to controller  28  via a communications link  55 . Processing circuitry  44 ,  45  may provide authentication functions, safety and operational interlocks, operating parameters and usage information related to imaging unit  32  and toner cartridge  35 , respectively. Controller  28  processes print and scan data and operates print engine  30  during printing and scanner system  40  during scanning. 
     Computer  24 , which is optional, may be, for example, a personal computer, including memory  60 , such as RAM, ROM, and/or NVRAM, an input device  62 , such as a keyboard and/or a mouse, and a display monitor  64 . 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 drive, a CD-ROM and/or a DVD unit (not shown). Computer  24  may also be a device capable of communicating with image forming device  22  other than a personal computer such as, for example, a tablet computer, a smartphone, or other electronic device. 
     In the example embodiment illustrated, computer  24  includes in its memory a software program including program instructions that function as an imaging driver  66 , e.g., printer/scanner driver software, for image forming device  22 . Imaging driver  66  is in communication with controller  28  of image forming device  22  via communications link  26 . Imaging driver  66  facilitates communication between image forming device  22  and 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 imaging driver  66  may be, for example, to facilitate collection of scanned data from scanner system  40 . 
     In some circumstances, it may be desirable to operate image forming device  22  in a standalone mode. In the standalone mode, image forming device  22  is capable of functioning without 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  so as to accommodate printing and/or scanning functionality when operating in the standalone mode. 
     Print engine  30  includes laser scan unit (LSU)  31 , toner cartridge  35 , imaging unit  32 , and fuser  37 , all mounted within image forming device  22 . Imaging unit  32  is removably mounted in image forming device  22  and includes a developer unit  34  that houses a toner sump and a toner delivery system. The toner delivery system includes a toner adder roll that provides toner from the toner sump to a developer roll. A doctor blade provides a metered uniform layer of toner on the surface of the developer roll. Imaging unit  32  also includes a cleaner unit  33  that houses a photoconductive drum and a waste toner removal system. Toner cartridge  35  is also removably mounted in imaging unit  32  in a mating relationship with developer unit  34  of imaging unit  32 . An exit port on toner cartridge  35  communicates with an entrance port on developer unit  34  allowing toner to be periodically transferred from toner cartridge  35  to resupply the toner sump in developer unit  34 . 
     The electrophotographic printing process is well known in the art and, therefore, is described briefly herein. During a printing operation, laser scan unit  31  creates a latent image on the photoconductive drum in cleaner unit  33 . Toner is transferred from the toner sump in developer unit  34  to the latent image on the photoconductive drum by the developer roll to create a toned image. The toned image is then transferred to a media sheet received in imaging unit  32  from media input tray  39  for printing. Toner remnants are removed from the photoconductive drum by the waste toner removal system. The toner image is bonded to the media sheet in fuser  37  and then sent to an output location or to one or more finishing options such as a duplexer, a stapler or a hole-punch. 
     Referring now to  FIG. 2 , a toner cartridge  100  and an imaging unit  200  are shown according to one example embodiment. Imaging unit  200  includes a developer unit  202  and a cleaner unit  204  mounted on a common frame  206 . Imaging unit  200  and toner cartridge  100  are each removably installed in image forming device  22  along a common entry path. Imaging unit  200  is first slidably inserted into image forming device  22 . Toner cartridge  100  is then inserted into image forming device  22  and onto frame  206  in a mating relationship with developer unit  202  of imaging unit  200  as indicated by the arrow shown in  FIG. 2 . This arrangement allows toner cartridge  100  to be removed and reinserted easily when replacing an empty toner cartridge without having to remove imaging unit  200 . Imaging unit  200  may also be readily removed as desired in order to maintain, repair or replace the components associated with developer unit  202 , cleaning unit  204  or frame  206  or to clear a media jam. 
     With reference to  FIGS. 2-5 , toner cartridge  100  includes a housing  102  having an enclosed reservoir  104  ( FIG. 5 ) for holding a quantity of toner therein. Housing  102  may be viewed as having a top or lid  106  mounted on a base  108 . Base  108  includes first and second side walls  110 ,  112  connected to adjoining front and rear walls  114 ,  116 . In one embodiment, top  106  is ultrasonically welded to base  108  thereby forming enclosed reservoir  104 . Housing  102  also includes first and second end caps  118 ,  120  that are mounted to side walls  110 ,  112 , respectively. First and second end caps  118 ,  120  may be snap fitted into place or attached by screws or other fasteners. A handle  122  may be provided on top  106  or base  108  of toner cartridge  100  to assist with insertion and removal of toner cartridge  100  from imaging unit  200  and image forming device  22 . As shown in  FIG. 6 , a fill port  124  is provided on side wall  112  that is used to fill toner cartridge  100  with toner. After filling, fill port  124  is closed by a plug  126  and/or cap  128 . 
     With reference to  FIG. 5 , various drive gears are housed within a space formed between end cap  118  and side wall  110 . A main interface gear  130  engages with a drive system in image forming device  22  that provides torque to main interface gear  130 . Various linkages may be housed within a space formed between end cap  120  and side wall  112  for actuating a shutter that regulates the flow of toner out of an exit port  132  provided in front wall  114  ( FIG. 3 ). One or more paddles  134  are rotatably mounted within toner reservoir  104  with first and second ends of a drive shaft  136  of paddle(s)  134  extending through aligned openings in side walls  110 ,  112 , respectively. A drive gear  138  is provided on the first end of drive shaft  136  that engages with main interface gear  130  either directly or via one or more intermediate gears. Bushings may be provided one each end of drive shaft  136  where it passes through side walls  110 ,  112 . Accordingly, side wall  110  may also be termed the “drive” or “driven” side of toner cartridge  100 . 
     With reference to  FIGS. 5 and 6 , an auger  140  having first and second ends  140   a ,  140   b , and a spiral screw flight  140   c  is positioned in a channel  142  extending along the width of front wall  114  between side walls  110 ,  112 . Channel  142  may be integrally molded as part of front wall  114  or formed as a separate component that is attached to front wall  114 . Channel  142  is generally horizontal in orientation along with toner cartridge  100  when toner cartridge  100  is installed in image forming device  22 . First end  140   a  of auger  140  extends through side wall  110  and a drive gear  144  is provided on first end  140   a  that engages with main interface gear  130  either directly or via one or more intermediate gears. Channel  142  includes an open portion  142   a  and an enclosed portion  142   b . Open portion  142   a  is open to toner reservoir  104  and extends from side wall  110  toward second end  140   b  of auger  140 . Enclosed portion  142   b  of channel  142  extends from side wall  112  and encloses second end  140   b  of auger  140  and the shutter that regulates whether toner is permitted to exit toner cartridge  100  through exit port  132 . As paddle(s)  134  rotate, they deliver toner from toner reservoir  104  into open portion  142   a  of channel  142 . Auger  140  is rotated via drive gear  144  to deliver toner received in channel  142  to the shutter housed in enclosed portion  142   b  of channel  142 . In this embodiment, exit port  132  is disposed at the bottom of channel  142  so that gravity will assist in exiting toner through exit port  132  ( FIG. 3 ). 
     With reference back to  FIG. 2 , when toner cartridge  100  is installed in image forming device  22 , its various interface features must align with corresponding interface features on imaging unit  200  and image forming device  22 . In its final position in image forming device  22 , toner cartridge  100  is positioned above frame  206  of imaging unit  200  with exit port  132  ( FIG. 3 ) aligned and mated with an entrance port  208  on developer unit  202 . In its final position, toner cartridge  100  does not apply a loading force on developer unit  202 . As discussed above, exit port  132  and entrance port  208  must be precisely aligned in order to prevent toner leakage between toner cartridge  100  and developer unit  202 . Further, main interface gear  130 , which is exposed on front wall  114  between side wall  110  and end cap  118 , must align and mate with a corresponding drive gear in image forming device  22  that provides torque to main interface gear  130 . If main interface gear  130  is misaligned, proper gear mesh may not be achieved, which may result in gear cogging. In addition, electrical contacts for processing circuitry  45  of toner cartridge  100  positioned within a connector  145  on end cap  118  must align and mate with corresponding electrical contacts in image forming device  22  in order to permit communication between toner cartridge  100  and image forming device  22 . The positions of these various interface points must be tightly controlled in order to ensure proper operation of toner cartridge  100 . As a result, toner cartridge  100  must be properly positioned from front-to-rear (direction “x” in  FIG. 2 ), vertically (direction “y”) and side-to-side or axially (direction “z”). The angle of insertion of toner cartridge (“Θ”), also referred to as yaw, must also be controlled to within an acceptable range in order to ensure proper positioning. 
     With reference to  FIGS. 2 and 7 , toner cartridge  100  and imaging unit  200  include both coarse and fine axial positioning features. Toner cartridge  100  includes a pair of legs  146 ,  148  projecting downward from base  108 . Legs  146 ,  148  are spaced along axial direction “z” from each other between end caps  118 ,  120 . Legs  146 ,  148  extend along base  108  from a rear portion of toner cartridge toward front wall  114  parallel to direction of insertion “x.” A front portion of leg  148  includes a slot  150  therein that permits an engagement feature on frame  206 , such as a fin  210 , to engage the linkages positioned between end cap  118  and side wall  110  to open the shutter when toner cartridge  100  is inserted into image forming device  22 . Frame  206  of imaging unit  200  includes a pair of vertical walls  212 ,  214  that correspond with legs  146 ,  148 . Each vertical wall  212 ,  214  includes a beveled front surface  212   a ,  214   a  that is outwardly angled with respect to the direction of insertion “x” and faces toner cartridge  100  as toner cartridge  100  advances toward imaging unit  200 . Each vertical wall  212 ,  214  also includes an inner surface  212   b ,  214   b  that is substantially parallel to the direction of insertion “x” of toner cartridge  100 . Inner surfaces  212   b ,  214   b  are spaced inward from front surfaces  212   a ,  214   a , respectively, along direction “x” toward developer unit  202 . As toner cartridge  100  is inserted into image forming device  22 , front surfaces  212   a ,  214   a  guide toner cartridge  100  toward developer unit  202  and limit the travel of toner cartridge  100  in the axial direction “z.” If toner cartridge  100  is misaligned in the axial direction “z” during insertion, an outer surface  146   a ,  148   a  of one of its legs  146 ,  148  will contact the corresponding front surface  212   a  or  214   a  of vertical walls  212 ,  214 . The angle of the front surface  212   a  or  214   a  will then urge toner cartridge  100  toward its proper axial alignment thereby providing coarse positional control as toner cartridge  100  advances toward developer unit  202 . 
     As toner cartridge  100  is advanced further, outer surfaces  146   a ,  148   a  of legs  146 ,  148  are restrained between inner surfaces  212   b ,  214   b  of vertical walls  212 ,  214  further limiting the travel of toner cartridge  100  in the axial direction. In the example embodiment illustrated, the distance between outer surface  146   a  of leg  146  and outer surface  148   a  of leg  148  is between about 266 mm and about 269 mm. These coarse axial control features lead to fine axial control features in the form of a tightly controlled slot and tab interface shown in  FIG. 8 .  FIG. 8  illustrates a cross-sectional view of toner cartridge  100  and imaging unit  200  taken along line  8 - 8  in  FIG. 7  with toner cartridge  100  advanced closer to imaging unit  200 . As shown in  FIG. 8 , a vertical wall  216  is spaced inward from vertical wall  212  along axial direction “z” forming a slot  218  therebetween. Specifically, slot  218  is formed between inner surface  212   b  of vertical wall  212  and an outer surface  216   a  of vertical wall  216 . As toner cartridge  100  is advanced closer to developer unit  202 , a front portion of leg  146  is received in slot  218  in frame  206  permitting slot  218  to tightly maintain the axial position of toner cartridge  100  as discussed in greater detail below. 
     With reference to  FIGS. 9-11 , the side surface of each end cap  118 ,  120  includes a wing guide  160 ,  170  (for end cap  120  and wing guide  170  see  FIGS. 3 and 4 ). Each wing guide  160 ,  170  includes a generally elongated body  161 ,  171  that extends from a rear portion of its end cap  118 ,  120  toward a front portion thereof. Wing guides  160 ,  170  are substantially parallel to each other. As toner cartridge  100  is inserted into image forming device  22 , wing guides  160 ,  170  each travel in a predetermined insertion path  300  defined by top and bottom guides  302 ,  304  running along an inner surface of image forming device  22 . A top surface  162 ,  172  of each wing guide  160 ,  170  includes a substantially planar rear portion  162   a ,  172   a  that extends from a rear portion of its end cap  118 ,  120  toward a front portion thereof. Each top surface  162 ,  172  also includes a front portion  162   b ,  172   b  that is angled downward with respect to rear portion  162   a ,  172   a , respectively. A stop  163 ,  173  extends vertically upward from each top surface  162 ,  172 , respectively, that limits the forward travel of toner cartridge  100  as it is inserted into image forming device  22  as discussed in greater detail below. Each wing guide  160 ,  170  also includes a tapered nose  164 ,  174 , respectively, forming a front tip thereof. In the example embodiment illustrated, a bottom surface  165 ,  175  of each respective wing guide  160 ,  170  includes three rounded projections  166   a ,  166   b ,  166   c  and  176   a ,  176   b ,  176   c  that define contact points with bottom guide  304  of image forming device  22 . Wing guides  160 ,  170  are sometimes referred to as “dog bone” shaped because of the shape formed by bodies  161 ,  171  combined with rounded projections  166   b ,  166   c  and  176   b ,  176   c . Top surface  162 ,  172  of each respective wing guide  160 ,  170  includes a pair of rounded projections  167   a ,  167   b ,  177   a  and  177   b.    
     Each end cap  118 ,  120  also includes an engagement surface  152 ,  154  projecting upwardly from a top portion of the respective end cap  118 ,  120 . Each engagement surface  152 ,  154  includes an angled front surface  152   a ,  154   a  that faces imaging unit  200  during insertion and an angled rear surface  152   b ,  154   b  that faces away from imaging unit  200  during insertion. 
     With reference to  FIG. 9 , as toner cartridge  100  is first inserted into image forming device  22 , a roller  306  in image forming device  22  that is biased into the insertion path of toner cartridge  100  contacts front surfaces  152   a ,  154   a  of engagement surfaces  152 ,  154 . The force applied to toner cartridge  100  by roller  306  controls the entry of toner cartridge  100  and prevents it from advancing into image forming device  22  too quickly. Further, as toner cartridge  100  is first inserted into image forming device  22 , the downwardly angled front portions  162   b ,  172   b  and tapered nose  164 ,  174  of wing guides  160 ,  170  provide the user with a relatively broad range of permissible angles of insertion Θ (or yaw). As toner cartridge  100  advances, the insertion angle is limited by projections  167   a ,  167   b ,  177   a ,  177   b  on top surfaces  162 ,  172  and front projections  166   a ,  176   a  on bottom surfaces  165 ,  175  as shown. 
     With reference to  FIG. 10 , as toner cartridge  100  is advanced to its final position, roller  306  passes over an apex  152   c ,  154   c  of each engagement surface  152 ,  154  until it contacts rear surfaces  152   b ,  154   b . The force applied by roller  306  to rear surfaces  152   b ,  154   b  of toner cartridge  100  urges toner cartridge  100  to its final position in image forming device  22 . As toner cartridge  100  advances, stops  163 ,  173  contact top guide  302  in image forming device  22  to prevent toner cartridge  100  from advancing further thereby controlling the front-to-rear horizontal positioning of toner cartridge  100  along direction “x.” The vertical position of toner cartridge  100  along direction “y” is controlled by the contact between rounded projections  166   b ,  166   c ,  176   b ,  176   c  and bottom guides  304  in image forming device  22 . Specifically, three of the four rounded projections  166   b ,  166   c ,  176   b ,  176   c  form datum points that define a plane that determines the vertical position of toner cartridge  100 . For example, in the example embodiment shown, the radii of rounded projections  166   b ,  166   c  and  176   b  are the same while the radius of rounded projection  176   c  is slightly smaller. As a result, in this embodiment, rounded projections  166   b ,  166   c  and  176   b  control the vertical position of toner cartridge  100 . 
     With reference to  FIG. 11 , accurate positioning of toner cartridge  100  permits proper alignment between the various interface features of toner cartridge  100  and the corresponding interface features on imaging unit  200  and image forming device  22 . As shown, in its final position, exit port  132  of toner cartridge  100  is aligned and mated with entrance port  208  on developer unit  202 . Main interface gear  130  is aligned and mated with a corresponding drive gear  308  in image forming device  22 . Electrical contacts for the processing circuitry in connector  145  are aligned and mated with corresponding electrical contacts on a connector  310  in image forming device  22 . The positional control features of toner cartridge  100  ensure that these interface points are tightly controlled in order to ensure proper operation of toner cartridge  100 . During operation, the force applied by roller  306  on rear surfaces  152   b ,  154   b  of engagement surfaces  152 ,  154  holds toner cartridge  100  in position and prevents it from separating from entrance port  208 , drive gear  308  or electrical contacts  310 . 
       FIGS. 12A-C ,  13 A-C and  14 A-C are sequential views illustrating the insertion of toner cartridge  100  into image forming device  22 .  FIGS. 12A-C  and  13 A-C show the positions of wing guides  160 ,  170 , respectively, relative to insertion path  300  as toner cartridge  100  is inserted into image forming device  22 .  FIGS. 14A-C  show cross-sectional views of leg  146  of toner cartridge  100  taken along line  14 - 14  in  FIG. 2 .  FIGS. 12A, 13A and 14A  show a first sequence view as toner cartridge  100  is initially inserted into image forming device  22 . Specifically,  FIGS. 12A and 13A  show wing guides  160 ,  170 , respectively, entering their respective insertion paths  300 .  FIG. 14A  shows a front portion  180  of leg  146  entering slot  218  in frame  206 . As illustrated, front portion  180  of leg  146  tapers in width forming a tab or nose  182  at a front tip thereof. In one embodiment, the width of nose  182  is between about 5 mm and about 9 mm. Slot  218  includes a corresponding tapered lead-in  220  to receive and guide front portion  180  of leg  146  into slot  218 . Slot  218  also includes an inner slot portion  222  sized to tightly receive nose  182 .  FIGS. 12B, 13B and 14B  show a second sequence view as toner cartridge  100  is advanced further into image forming device  22 .  FIGS. 12B and 13B  show wing guides  160 ,  170 , respectively, advanced further along their respective insertion paths  300 .  FIG. 14B  shows front portion  180  of leg  146  advanced further in slot  218 .  FIGS. 12C, 13C and 14C  show a final sequence view with toner cartridge  100  fully inserted into image forming device  22  and mated with developer unit  202 .  FIGS. 12C and 13C  show stops  163 ,  173  engaged with a corresponding lip or rounded stop  312  in image forming device  22 . Stops  312  control the position of toner cartridge  100  in the direction of insertion and ensure that toner cartridge  100  is not over-inserted into image forming device  22 .  FIGS. 12C and 13C  also show rounded projections  166   b ,  166   c  and  176   b , positioned on bottom guide  304  and rounded projections  166   a ,  176   a  and  176   c  spaced from bottom guide  304 . As discussed above, in this embodiment, rounded projections  166   b ,  166   c  and  176   b  define a plane that controls the vertical position of toner cartridge  100 .  FIG. 14C  shows nose  182  tightly positioned in inner slot portion  222  to control the axial position of toner cartridge  100 . 
       FIG. 15  shows a toner cartridge  400  having positional control features and a corresponding imaging unit  500  according to a second example embodiment. Imaging unit  500  includes a developer unit  502  and a cleaner unit  504  mounted on a common frame  506 . Developer unit  502  includes an entrance port  508  for receiving toner from toner cartridge  400 . Frame  506  includes a projection  510  for actuating a shutter that regulates the flow of toner out of toner cartridge  400  similar to fin  210  discussed above. As discussed above, imaging unit  500  and toner cartridge  400  are each removably installed in image forming device  22 . In its final position, toner cartridge  400  is in a mating relationship with developer unit  502  of imaging unit  500 . Toner cartridge  400  includes a housing  402  having a top or lid  406  mounted on a base  408 . Base  408  includes first and second side walls connected to adjoining front and rear walls  414 ,  416 . First and second end caps  418 ,  420  are mounted to the side walls, respectively. A main interface gear  430  is exposed on front wall  414  between end cap  418  and its respective side wall. Main interface gear engages with a drive system in image forming device  22  that provides torque to main interface gear  430 . An exit port  432  is disposed on front wall  414  in a downward facing orientation so that gravity will assist in exiting toner through exit port  432 . Toner cartridge  400  also includes electrical contacts for processing circuitry positioned within a connector  445  on end cap  420  ( FIG. 16 ). 
     With reference to  FIGS. 15 and 16 , toner cartridge  400  and imaging unit  500  include both coarse and fine axial positioning features. The coarse axial positioning features are similar to those discussed above with respect to toner cartridge  100  and imaging unit  200 . Toner cartridge  400  includes a pair of legs  446 ,  448  extending downward from base  408 . Frame  506  of imaging unit  500  includes a pair of vertical walls  512 ,  514  that form a guide  516  therebetween that receives leg  446  and a pair of vertical walls  518 ,  520  that form a guide  522  therebetween that receives leg  448  as toner cartridge  400  is inserted into image forming device  22 . Each vertical wall  512 ,  514 ,  518 ,  520  includes a beveled front surface  512   a ,  514   a ,  518   a ,  520   a  that is outwardly angled with respect to the direction of insertion and faces toner cartridge  400  as toner cartridge  400  advances toward imaging unit  500 . Front surfaces  512   a ,  514   a ,  518   a ,  520   a  guide toner cartridge  400  toward developer unit  502  as toner cartridge  400  is inserted into image forming device  22 . Each vertical wall  512 ,  514 ,  518 ,  520  also includes an inner surface  512   b ,  514   b ,  518   b ,  520   b  that is substantially parallel to the direction of insertion of toner cartridge  400 . Inner surfaces  512   b ,  514   b ,  518   b ,  520   b  restrain outer surfaces  446   a ,  448   a  of legs  446 ,  448  limiting the travel of toner cartridge  400  in the axial direction. In the example embodiment illustrated in  FIGS. 15 and 16 , the distance between outer surface  446   a  of leg  446  and outer surface  448   a  of leg  448  is between about 255 mm and about 258 mm. 
       FIG. 17  illustrates a cross-sectional view of toner cartridge  400  and imaging unit  500  taken along line  17 - 17  in  FIG. 16 . As shown in  FIG. 17 , a post  524  is spaced axially inward from guide  516  and extends upward from frame  506  of imaging unit  500 . Toner cartridge  400  includes a slot  490  formed between a pair of substantially parallel walls  492 ,  494  that extend forward and downward from base  408 . Slot  490  is spaced axially inward from leg  446 . In the example embodiment illustrated in  FIG. 17 , the width of slot  490  is between about 6.3 mm and about 8.3 mm. As toner cartridge  400  is advanced toward developer unit  502 , post  524  on imaging unit  500  is tightly received in slot  490  on toner cartridge  400  permitting slot  490  to precisely maintain the axial position of toner cartridge  400 . As desired, post  524  and/or slot  490  may include a tapered lead-in section to facilitate engagement between the two. 
     With reference back to  FIGS. 15 and 16 , the side surface of each end cap  418 ,  420  includes a wing guide  460 ,  470 . Each wing guide  460 ,  470  includes the “dog bone” structure described above with respect to wing guides  160 ,  170  of toner cartridge  100 . As discussed above, wing guides  460 ,  470  control the front-to-rear horizontal positioning and vertical positioning of toner cartridge  400 . Each end cap  418 ,  420  also includes an engagement surface  452 ,  454  projecting upwardly from a top portion of the respective end cap  418 ,  420 . As discussed above, each engagement surface  452 ,  454  includes an angled front surface  452   a ,  454   a  that faces imaging unit  500  during insertion and an angled rear surface  452   b ,  454   b  that faces away from imaging unit  500  during insertion. During operation, rear surfaces  452   b ,  454   b  of engagement surfaces  452 ,  454  receive a hold-down force from a component in image forming device  22  to ensure that exit port  432 , main interface gear  430  and the electrical contacts for processing circuitry on connector  445  maintain their engagement with imaging unit  500  or image forming device  22 . 
     The foregoing description of several embodiments has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the application to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is understood that the invention may be practiced in ways other than as specifically set forth herein without departing from the scope of the invention. It is intended that the scope of the application be defined by the claims appended hereto.