Waste bottle with overflow chamber

Information

  • Patent Grant
  • 6353722
  • Patent Number
    6,353,722
  • Date Filed
    Tuesday, December 19, 2000
    23 years ago
  • Date Issued
    Tuesday, March 5, 2002
    22 years ago
Abstract
A container for collecting waste developer in an electrostatographic printing machine employing a trickle type developing process and having a waste developer discharge tube with a discharge opening adjacent an outer end thereof for discharging waste developer. The container includes an outer wall enclosing an interior chamber, with a partition wall extending from an inner surface of the outer wall dividing the inner chamber into a collection chamber and an overflow chamber. An opening is formed in the outer wall into the overflow chamber. The opening is sized and shaped to receive the discharge tube therethrough. When received through the opening, the discharge tube extends through the overflow chamber, over an inner edge of the partition wall and into the collection chamber, with the discharge opening being located within the collection chamber. With this construction, the waste developer is discharged into the collection chamber.
Description




FIELD OF THE INVENTION




This invention relates generally to an electrophotographic printing machine, and more particularly concerns a waste developer bottle for collecting and disposing of waste developer.




BACKGROUND OF THE INVENTION




In the process of electrophotographic printing, a charge-retentive surface, also known as a photoreceptor, is charged to a substantially uniform potential, so as to sensitize the surface of the photoreceptor. The charged portion of the photoconductive surface is exposed to a light image of an original document being reproduced, or else a scanned laser image created by the action of digital image data acting on a laser source. The scanning or exposing step records an electrostatic latent image on the photoreceptor corresponding to the informational areas in the document to be printed or copied. After the latent image is recorded on the photoreceptor, the latent image is developed by causing toner particles to adhere electrostatically to the charged areas forming the latent image. This developed image on the photoreceptor is subsequently transferred to a sheet on which the desired image is to be printed. Finally, the toner on the sheet is heated to permanently fuse the toner image to the sheet.




One familiar type of development of an electrostatic image is called “two-component development.” Two-component developer material largely comprises toner particles interspersed with carrier particles. The carrier particles are magnetically attractable, and the toner particles are caused to adhere triboelectrically to the carrier particles. This two-component developer can be conveyed, by means such as a “magnetic roll,” to the electrostatic latent image, where toner particles become detached from the carrier particles and adhere to the electrostatic latent image.




Despite the practical advantages of two-component development, which has caused this type of development to become very common in printers and copiers available today, a common problem involving two-component development relates to the degradation of two-component developer material over the life of a printer or copier. One print quality problem results from the fact that, as the toner in developer material is gradually consumed by being placed on the photoreceptor, and then from the photoreceptor onto print sheets, a constant quantity of carrier particles remains in the system. Over time, the ratio of toner to carrier particles in the developer mixture drifts from an optimal level. Further, the frequency of print quality defects tends to increase with the increasing length of service of a two-component development system. Such print quality defects may be caused by dirt generation from developer material that is nearing the end of its useful life. At service calls, however, developer material is frequently changed without knowing the condition thereof, often resulting in wasteful discarding of developer material that is still of satisfactory quality.




U.S. Pat. No. 4,614,165, assigned to the assignee hereof and incorporated by reference herein, discloses the general principle of what is known familiarly as “trickle” development. Very briefly, trickle development involves providing two distinct supplies of developer: a main supply, from which the development unit draws developer for application to the electrostatic latent image, and a second, separate developer supply which is used to replenish the first supply over time. Typically, the two quantities of developer have substantially different ratios of toner to carrier. In the embodiment described in the '165 patent, for example, the first developer supply in the housing of the development unit is 96% carrier by weight and 4% toner by weight, while the developer material being gradually dispensed into the first supply is 25% carrier by weight and 75% toner by weight. Over the course of the lifetime of the printer, or at least of the development unit, the relatively toner-rich developer in the second supply is gradually discharged, or caused to “trickle,” into the first developer supply. This trickling provides a substantially continuous replenishment of toner rich developer, and thereby maintains the effective ratio of toner to carrier within the main developer supply within an optimal range for a longer period of time. This trickling thereby extending the useful life and the optimal print quality associated with the development unit.




In a trickle development system, as a fresh supply of developer is discharged into the housing of the development unit, it is typically necessary that a similar quantity of surplus developer be discharged from the housing of the development unit. This surplus or “waste” material is commonly collected in a waste bottle. An auger contained in a transport tube is often used to transport the waste material through the tube to the waste bottle. The transport tube, with the auger therein, typically extends through a seal in an opening in the waste bottle. Waste material traveling through the transport tube is discharged into the waste bottle through an opening in the tube.




When the waste bottle becomes filled with waste developer, it is necessary to remove the full bottle and replace it with an empty bottle. The bottle is removed from the development unit by sliding the bottle off the end of the transport tube. If the waste bottle is filled to the top with developer, waste developer in the bottle is dragged by the auger vanes, which are exposed through the opening in the transport tube, and by the edges of the opening in the tube through the seal in the bottle. When the opening in the transport tube clears the seal, the developer that has been dragged through the seal falls from the auger and the transport tube into the machine. As a result, the interior of the machine becomes soiled with developer.




There is a need in the art for a toner waste bottle that can be removed from the waste auger without developer being dragged through the seal and soiling the machine.




SUMMARY OF THE INVENTION




One form of the invention provides a container for collecting waste developer discharged from a developer module through a waste developer discharge conduit, comprising: a housing defining a chamber including a partition wall dividing the chamber into a collection chamber and an overflow chamber, said housing having an opening formed in the region of the overflow chamber to receive said discharge conduit therethrough, said discharge conduit extending through said overflow chamber, over an inner edge of said partition wall and into said collection chamber, so that waste developer is discharged into said collection chamber.




Another form of the invention provides an electrostatographic reproduction machine comprising: a developer module having a discharge conduit extending therefrom for discharging waste developer from said developer module; a waste collection bottle enclosing a chamber including a partition wall separating said chamber into a collection chamber and an overflow chamber, said bottle having an inlet opening in the region of said overflow chamber, said discharge conduit extending through said inlet opening, through said overflow chamber, over an inner edge of said partition wall and into said collection chamber, such that said waste developer is discharged into said collection chamber.











BRIEF DESCRIPTION OF THE DRAWINGS




The invention will now be described, by way of example, with reference to the accompanying drawings, of which:





FIG. 1

is an illustrative cross-sectional view of a trickle type developer module having a developer waste bottle attached thereto;





FIG. 2

is a cross-sectional side view of a developer waste bottle according to the present invention attached to a developer module; and





FIG. 3

is a cross-sectional view showing the waste bottle of

FIG. 2

in the process of being removed from the developer housing.











DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION




While the present invention will be described by way of example with reference to one form of the present invention, it will be understood that it is not intended to limit the invention to the described embodiment. On the contrary, the present invention is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.





FIG. 1

depicts the developer module


2


of an illustrative electrophotographic printing machine having a developer waste bottle


4


according to one form of the present invention. It will become evident from the following discussion that the disclosed waste bottle


4


is equally well suited for use in a wide variety of printing machines and is not necessarily limited in its application to the particular printing machine described herein.




As shown in

FIG. 1

, the illustrative electrophotographic printing machine employs a drum


10


having a photoconductive surface


12


adhering to a conductive substrate. The photoconductive surface may comprise a selenium alloy with the conductive substrate being an electrically grounded aluminum alloy. The drum


10


moves in the direction of arrow


14


to advance successive portions of the photoconductive surface


12


sequentially through the various processing stations A-E disposed about the periphery of the drum


10


.




For purposes of the present disclosure, the several generally conventional electrophotographic processing stations in the path of movement of the photoconductive surface may be as follows. A charging station A, where the photoconductive surface


12


of the drum


10


is uniformly charged. An exposure station B, where a light or radiation pattern of a document to be printed is projected onto the photoconductive surface


12


to expose and discharge select areas of the photoconductive surface to form a latent image thereon. A developing station C, where xerographic developer is electrostatically applied to the photoconductive surface


12


of the drum to generate a toner image on the photoconductive surface. A transfer station D, where the toner image is electrostatically transferred from the photoconductive surface to a print sheet. Finally, a cleaning station E, where the photoconductive surface


12


is brushed or otherwise cleared of residual toner particles remaining thereon after image transfer.




Print sheets (not shown) supplied from a sheet feeding tray (not shown), are fed by appropriate conveying means (not shown) to the transfer station D. At the transfer station, the developed toner image is transferred from the photoconductive surface


12


of the drum


10


to the sheet. The sheet is then stripped from the photoreceptor belt by a sheet stripper


16


and transported to a fusing station (not shown), where the toner image is fused to the print sheet in a known manner. The print sheet, which now has an image fused to a first face thereof, is then transported to an output tray (not shown).




The developer module


2


is located at the developing station C. The developing unit includes a developer housing


20


defining a developer chamber


22


storing a supply of developer material including carrier granules and toner particles (not shown). A tubular sleeve


24


is rotatably mounted on a shaft within the developer chamber


22


. An elongate cylindrical magnet


26


is mounted inside sleeve


24


. The magnet is mounted stationarily within the sleeve and has a plurality of magnetic poles formed on its outer circumferential surface to generate a magnetic field. A motor (not shown) rotates the sleeve


24


in the direction of arrow


28


. The developer material is attracted to the sleeve by the magnetic field generated by the magnet, and the rotation


28


of the sleeve transports the developer material attracted thereto closely adjacent to or into contact with the photoconductive surface


12


at the developing station C. The toner particles in the developer are attracted from the carrier granules to the latent image recorded on the photoconductive surface


12


of the drum


10


, thereby developing a toner image on the drum. The sleeve


24


is electrically biased by a voltage source (not shown) in a known manner, in order to facilitate transfer of the toner from the carrier beads to the latent image on the drum.




As the latent image is being developed at the developing station C, the toner particles are being depleted form the developer material in the developer chamber


22


and require replenishment to maintain the carrier to toner ratio within an optimum range. In addition, the carrier granules and toner particles in the chamber age and must periodically be replaced in order to maintain the desired print quality. In order to provide the developer in the developer module with a useful life, preferably at least as long as the useful life of the photoconductive surface


12


on the drum


10


, a replenishing stream of a toner rich mixture of carrier granules and toner particles, (replenisher) is trickled into the developer


22


.




A discharging unit, indicated generally by the reference numeral


30


, dispenses replenisher to developer chamber


22


. Discharging unit


30


is shown as being adjacent to the developer chamber


22


in the developer housing


20


. However, one skilled in the art will appreciate that the discharging unit may be located within the chamber


22


or remote therefrom as well. Discharging unit


30


includes hopper


32


having a segmented feed roller


34


positioned in a lower end thereof. Replenisher is stored in the hopper


32


. As the feed roller


34


rotates, replenisher is discharged from the hopper into developer chamber


22


. The ratio of toner particles to carrier granules by weight in the replenisher being discharged from hopper is substantially greater than the ratio of toner particles to carrier granules by weight in the developer material in the developer chamber


22


. By way of example, the replenisher being dispensed from discharging unit may be 25% carrier granules by weight and 75% toner particles by weight, while the developer material in the developer chamber may be about 96% carrier granules by weight and 4% toner particles by weight.




As developer is trickled into the developer chamber


22


, it is often necessary to remove excess developer material from the developer chamber


22


, in order to maintain the proper level of developer in the developer chamber. This excess or waste developer material escapes through an opening


36


in the developer housing


20


outer wall, down a short duct


38


and into a transport or auger tube


40


containing an auger


42


. A motor (not shown) rotates the auger, whereby the auger rotates in the tube, such that the vanes


44


of the auger transport the waste developer through the auger tube to the waste bottle


4


. The waste developer is collected in the waste bottle. Over time, the waste bottle


4


becomes filled with developer and must be removed from the machine and replaced with an empty bottle.




Referring now to

FIGS. 2 and 3

, the illustrated waste bottle


4


is designed to fit in a long narrow space in an electrostatic reproducing machine. As such, the bottle is long, narrow and short, as opposed to tall, in shape, in order to take full advantage of the available space. A neck


50


is formed in the inboard end


52


of the bottle


4


, near the top of the bottle. A doughnut shaped resilient seal


54


is sealingly affixed in the neck


50


of the bottle. The seal may be formed of open celled polyurethane foam, or other suitable material. The body or outer wall


56


of the bottle is shaped to define a waste collection chamber


58


and an overflow chamber


60


located between the collection chamber and the neck


50


of the bottle. The outboard end


62


of the bottle may be shaped to formed a handle


64


for grasping the bottle and removing it from the machine and an enlarged portion


66


in the collection chamber


58


for maximizing the storage capacity of the waste bottle


4


.




The auger tube


40


and the auger


42


extend through the seal


54


in the neck


50


of the waste bottle


4


, and through the interior of the bottle to the outboard end


62


of the bottle. The opening in the center of the seal


54


is formed with a diameter that is somewhat smaller than the outer diameter of the auger tube


40


, such that an airtight seal is formed between the neck of the bottle and the auger tube. A tapered nose


68


on the end of the auger tube


40


is received in a mating recess


70


formed in the inner surface of the outboard end


62


of the bottle. The taper on the nose of the auger facilitates insertion of the auger through the hole in the seal


54


. The portion of the auger tube


40


located in the collection chamber has a large longitudinally extending slot passing therethrough, such that approximately the lower half of the auger tube is open exposing the auger vanes


44


inside the collection chamber


58


. The portion of the auger tube located in the overflow chamber


60


is not slotted. The unslotted portion of the auger tube meshes with or matingly abuts up against a partition


74


wall that separates the overflow chamber


60


from the collection chamber


58


.




As previously described, the auger


42


is rotated by a motor (not shown) and thereby transports the waste developer through the auger tube


40


and into the waste bottle


4


. The waste material travels through the unslotted portion of the auger tube, past the overflow chamber


60


, and into the slotted portion of the auger tube located in the collection chamber


58


. The waste developer falls through the open bottom


72


of the auger tube into the collection chamber where it is collected. The waste developer piles up at the inboard end


52


of the bottle, until the top of the pile contacts the vanes


44


of the auger


42


, as illustrated in FIG.


2


. As more waste developer is transported through the auger tube and into the bottle, the waste developer is transported along the top of the pile by the auger vanes and drops the down the outboard side of the pile. The waste bottle is thus slowly filled form its inboard end


52


to its outboard end


62


, as indicated by arrow


80


in FIG.


2


.




When the bottle


4


is filled with waste toner, as depicted in

FIG. 3

, the waste material building up against the outboard end


62


of the bottle trips a magnetic switch (not shown), or other suitable sensor, on the outside of the bottle. The switch sends a signal to the machine's controller (not shown), and the controller provides a message or signal to the customer or service technician informing them that the waste bottle is full. The customer or technician then replaces the bottle with an empty waste bottle. The full waste bottle is returned to the manufacturer for recycling of the bottle and developer material, or other suitable disposal of the waste developer and bottle.




In order to remove a full waste bottle


4


from the machine, the bottle is grasped by the handle


64


and pulled outward as indicated by arrow


82


in FIG.


3


. As the bottle is moved out of the machine, the neck


50


of the bottles slides along the auger tube


40


, until the neck of the bottle clears the nose


68


of the auger tube. Some of the waste developer collected in the collection chamber


58


is dragged toward the neck of the bottle by the auger vanes


44


(to the left in FIG.


3


). The partition wall


74


traps the vast majority of the waste developer inside the collection chamber


58


. Some of the waste developer being dragged by the auger vanes, however, is dragged over the partition wall


74


by the auger vanes. Since the overflow chamber


60


is void of developer, the waste developer that is dragged over the partition wall falls from the auger vanes


44


and is collected in the overflow chamber


60


. As a result, the auger vanes are cleared of waste developer prior to passing through the seal


54


in the neck


50


of the bottle, and developer is substantially prevented from being dragged through the seal and falling off the auger into the machine.




An exemplary embodiment of the present invention has been described. After reading the description, those skilled in the art will identify various modifications that can be made to the embodiments described above without departing from the invention. For example, waste bottles having other shapes or overall proportions, other than the long narrow bottle illustrated and described, may incorporate an overflow chamber according to the present invention. Also, other mechanisms and or structures may be employed in the structure of the discharge unit


30


and the developer module


2


. For example, an alternative feed mechanism, such as an auger or some sort of valve, may be employed in place of the described segmented roller


34


to control the discharge or trickle of replenisher from the discharge unit


30


. Similarly, some sort of feed mechanism or valve may be employed to control the flow of waste developer being discharged from the developer housing


20


into the auger tube


40


. Therefore, the above description is illustrative, and the scope of the claimed invention is not intended to be limited to the particular embodiments described above.



Claims
  • 1. A container for collecting waste developer discharged from a developer module through a waste developer discharge conduit, comprising:a housing defining a chamber including a partition wall dividing the chamber into a collection chamber and an overflow chamber, said housing having an opening formed in the region of the overflow chamber to receive said discharge conduit therethrough, said discharge conduit extending through said overflow chamber, over an inner edge of said partition wall and into said collection chamber, so that waste developer is discharged into said collection chamber.
  • 2. The container of claim 1, wherein said inner edge of said partition wall abuts against an outer peripheral surface of said discharge conduit.
  • 3. The container of claim 1, further comprising an auger in said discharge conduit, said auger including vanes extending along the length thereof.
  • 4. The container of claim 1, further comprising a seal mounted in the opening of said housing, said seal engaging an outer peripheral surface of said discharge conduit to form a seal.
  • 5. The container of claim 4, wherein said seal comprises a ring-shaped foam member.
  • 6. An electrostatographic reproduction machine comprising:a developer module having a discharge conduit extending therefrom for discharging waste developer from said developer module; a waste collection bottle enclosing a chamber including a partition wall separating said chamber into a collection chamber and an overflow chamber, said bottle having an inlet opening in the region of said overflow chamber, said discharge conduit extending through said inlet opening, through said overflow chamber, over an inner edge of said partition wall and into said collection chamber, such that said waste developer is discharged into said collection chamber.
  • 7. The machine of claim 6, wherein said inner edge of said partition wall nests with an outer peripheral surface of said discharge conduit.
  • 8. The machine of claim 6, further comprising a seal mounted in said inlet opening, said seal engaging an outer peripheral surface of said discharge conduit to form a seal.
  • 9. The machine of claim 8, wherein said seal is a generally annular foam member.
  • 10. The machine of claim 6, further comprising an auger in said discharge conduit, said auger including vanes extending along the length thereof.
  • 11. The machine of claim 10, further comprising a seal mounted in said inlet opening, said seal engaging an outer peripheral surface of said discharge conduit to form a seal.
US Referenced Citations (6)
Number Name Date Kind
4614165 Folkins et al. Sep 1986 A
4625895 Tsukano Dec 1986 A
4891673 Buell Jan 1990 A
5250749 Aimoto Oct 1993 A
5260747 Uwagawa et al. Nov 1993 A
5436703 DeYoung et al. Jul 1995 A
Foreign Referenced Citations (3)
Number Date Country
07-281571 Oct 1995 JP
10-232590 Sep 1998 JP
2000-98744 Apr 2000 JP