Toner cartridge

Information

  • Patent Grant
  • 6771922
  • Patent Number
    6,771,922
  • Date Filed
    Tuesday, December 31, 2002
    21 years ago
  • Date Issued
    Tuesday, August 3, 2004
    20 years ago
Abstract
A toner cartridge for use in a laser printer has a toner reservoir or hopper in which an agitator is pivoted by a rotating paddle away from its home position proximate an exit opening and then returned to its home position by a spring exerting a predetermined desired force on the agitator after the agitator ceases to be moved by the paddle. The spring may be a cantilever spring, a torsion spring, or a stamped and formed leaf spring.
Description




FIELD OF THE INVENTION




This invention relates to an improved toner cartridge for use in a laser printer and, more particularly, to a toner cartridge for use in a laser printer utilizing an arrangement for improving print quality and print speed.




BACKGROUND OF THE INVENTION




Print quality in a laser printer is improved when the size of the toner particles is reduced. This size reduction of the particles allows more of the particles to print in a specific area so that there is more overlapping of the particles during development of an image on a medium such as paper, for example.




It also is desired to increase print speed. This results in the need for a lower melt point toner so that the toner will fuse faster on the medium.




Lower melt point toners are more prone to clumping to make it more difficult to convey the toner from its supply hopper or reservoir to the image development zone of the laser printer. This is because lower melt point toners have inherently lower flow rates than previously employed toners with higher melt point temperatures.




Inadequate conveyance of the lower melt point toner due to its lower flow rates can lead to insufficient toner in the image development zone; this reduces print quality even though the size of the toner particles has been decreased to improve the print quality. This insufficient toner in the development zone is referred to as “toner starvation.”




Various mechanical arrangements have been employed to aid in conveyance of the toner. These include rotating rods, reciprocating rakes, gravity assisted inclines, and a pivotally mounted agitator, for example.




U.S. Pat. No. 5,875,378 to Campbell et al discloses an agitator pivotally mounted about its end points and located in a transition opening between the supply hopper and the image development zone. The agitator is driven upwardly by a rotating paddle, which passes through the toner in the supply hopper, to a point at which their curved paths separate. Then, the agitator falls by gravity until it returns to its home or rest position, which is proximate to an exit surface sloping downwardly during normal operation of the toner cartridge.




Falling of the agitator by gravity displaces toner in the transition zone, which is between the hopper and the image development zone, into the image development area because of the sweeping motion of the agitator. The weight of the agitator is employed to break up the particles of toner that tend to clump together.




When using a lower melt point toner, the agitator is eventually suspended upon a bed of toner through its repeated actuation by the toner paddle. As a result, the agitator has been found to be ineffective for causing transport of toner particles having a lower melt point. It has been discovered that an external tip load on the farthest reaching portion of the agitator requires 20-50 grams of force on the agitator to return it to its home or rest position when using a lower melt point toner.




This problem is solved through using resilient means such as a spring, for example, to provide an additional tip loading of 20-50 grams on a pivotally mounted agitator. This enables the improved toner cartridge to have a lower melt point toner for increased printing speeds while using particles of relatively smaller size to improve the print quality. Therefore, premature failure to print, which is termed “toner starvation,” is avoided.




SUMMARY OF THE INVENTION




A toner cartridge comprises a hopper having an opening for delivering toner out of the hopper, which has a lower wall extending from a bottom of the hopper to a location substantially above the bottom of the hopper to define a bottom of the opening. A paddle is rotatable in the hopper to stir toner such that some toner will move gently toward the opening. The cartridge also has an exit surface to deliver toner from the hopper on the side of the lower wall opposite the hopper with the exit surface sloping downwardly during normal operation of the cartridge. An agitator, which extends across the exit surface, has a first pivot member on one side of the exit surface and a second pivot member on an opposite side of the exit surface. The hopper has support pins for supporting the first pivot member and the second pivot member of the agitator to pivotally support the agitator on the hopper. The agitator is normally located at a home position proximate the exit surface except when moved by the paddle around the first pivot member and the second pivot member. An extension on the agitator extends past the lower wall into the path of the paddle in the hopper when the paddle is rotated. Resilient means mounted on the agitator exerts a force on the agitator to return the agitator to the home position after the agitator is moved from the home position by the paddle engaging the extension during rotation of the paddle and the paddle ceases to engage the extension.











BRIEF DESCRIPTION OF THE DRAWINGS




The attached drawings illustrate exemplary embodiments of the invention, in which:





FIG. 1

is a top right front perspective view of a toner cartridge of a laser printer where right is determined facing the laser printer from its front side where insertion of the toner cartridge is made with cover elements removed;





FIG. 2

is a top left rear perspective view of the cartridge with cover elements removed;





FIG. 3

is a front right perspective view of a hopper with one of its end walls removed and showing a spring used to return a toner agitator to its home position after it has been advanced therefrom by a rotatable paddle;





FIG. 4

is an end elevational view of a poi lion of the hopper with one of its end walls removed and the agitator in its home position;





FIG. 5

is an end elevational view of a portion of the hopper, similar to

FIG. 4

, with the one end wall removed and the agitator in its raised position and the spring engaged with an interior surface of the hopper;





FIG. 6

is a perspective view of the spring employed to return the agitator to its home position;





FIG. 7

is a perspective view of a portion of the agitator and showing initial positioning of the spring of

FIG. 6

on the agitator;





FIG. 8

is a perspective view, similar to

FIG. 7

, of a portion of the agitator and showing the spring pulled onto the agitator;





FIG. 9

is a perspective view, similar to

FIGS. 7 and 8

, of a portion of the agitator and showing the spring partially rotated from the position of

FIG. 8

;





FIG. 10

is a perspective view, similar to

FIGS. 7-9

, of a portion of the agitator and showing the spring fully rotated to its assembled position on the agitator;





FIG. 11

is a perspective view of a torsion spring employed to return the agitator to its home position;





FIG. 12

is a perspective view of the agitator with the torsion spring of

FIG. 11

mounted thereon;





FIG. 13

is a front left perspective view of a portion of the hopper with the agitator having the torsion spring of

FIG. 11

mounted thereon;





FIG. 14

is a perspective view of a stamped and formed leaf spring utilized for returning the agitator to its home position;





FIG. 15

is a perspective view of the agitator with the stamped and formed leaf spring of

FIG. 14

mounted thereon; and





FIG. 16

is a front left perspective view of the hopper with the agitator having the stamped and formed leaf spring of

FIG. 14

mounted thereon.











DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS




Referring to the drawings and particularly

FIG. 1

, there is shown a toner cartridge


10


for use in a laser printer. The toner cartridge


10


is inserted into the laser printer from the front and removable therefrom in the well-known manner.




The toner cartridge


10


includes a hopper


11


within which a paddle


12


is rotatably supported and driven by a drive element in the laser printer through a gear train including a gear


14


attached to a shaft


13


of the paddle


12


. The paddle


12


is rotated counterclockwise (as viewed in FIG.


1


).




To facilitate and guide insertion of the cartridge


10


into the laser printer, the cartridge


10


has a left guide wing


15


(see

FIG. 2

) and a right guide wing


16


. The guide wings


15


and


16


are mirror images of each other except that the left guide wing


15


is wider to accommodate the width provided by a particular printer in which the cartridge


10


is to be installed.




The hopper


11


includes a left end wall


17


and a right end wall


18


connected to opposite ends of a housing


19


of the hopper


11


to form a toner reservoir.




The paddle


12


has an outer toner moving bar


20


. The bar


20


extends across the width of the housing


19


except for a far left section


21


, which is inset for manufacturing purposes.




A rear wall


22


(see

FIG. 3

) of the hopper housing


19


terminates at about one-third of the total height of the interior of the hopper housing


19


as a flat surface


23


. The flat surface


23


has a slight downward angle from the hopper


11


.




An exit opening from the interior of the hopper


11


is defined by the flat surface


23


and a top wall


25


of the hopper


11


. An exit surface or wall


26


extends from the flat surface


23


of the rear wall


22


at an angle of approximately 50°. The exit surface or wall


26


is flat.




An agitator


27


extends across the flat surface


23


. As shown in

FIG. 12

, the agitator


27


includes a first body portion


28


and a second body portion


29


spaced from the first body portion


28


and connected thereto by connectors


30


to produce rectangular shaped openings


31


. The second body portion


29


is at an angle to the first body portion


28


.




The first body portion


28


has arms


32


and


33


integral therewith at its ends and extending therefrom. The arm


32


extends substantially perpendicular to the first body portion


28


, and the arm


33


is an angle greater than 90° to the first body portion


28


of the agitator


27


.




An extension


34


extends from the first body portion


28


of the agitator


27


at the end adjacent the arm


32


. The extension


34


includes a first portion


35


extending downwardly from the first body portion


28


of the agitator


27


and a second portion


36


inclined downwardly from the first portion


35


.




As shown in

FIG. 4

, the second portion


36


of the extension


34


rests on the flat surface


23


of the rear wall


22


of the hopper


11


. This positions the agitator


27


slightly above the flat surface


23


of the rear wall


22


of the hopper


11


.




A cantilever spring


38


(see FIG.


6


), which is formed of a music wire preferably having a diameter of 0.016″, is mounted on the first body portion


28


(see

FIG. 10

) of the agitator


27


. The spring


38


(see

FIG. 6

) includes a short leg


39


and a long leg


40


. An inclined portion


41


extends from the top of the long leg


40


and terminates in a curved portion


42


.




The legs


39


and


40


, which are substantially parallel to each other, are connected to each other by a base including a portion


43


extending from the short leg


39


and a portion


44


extending from the long leg


40


. The portions


43


and


44


are connected to each other by a portion


45


to form the base of the spring


38


.




As shown in

FIG. 7

, the spring


38


is initially positioned with the long leg


40


beneath the first body portion


28


of the agitator


27


. The spring


38


is then pulled from the position of

FIG. 7

to the position of

FIG. 8

in which the portion


45


extends over the first body portion


28


of the agitator


27


. Next, the spring


38


is rotated to the position of FIG.


9


. Finally, further rotation of the spring


38


from the position of

FIG. 9

to the position of

FIG. 10

mounts the spring


38


in the desired position on the agitator


27


. This uniquely wrapped base of the portions


43


-


45


of the spring


38


eliminates the need for any fastener or retainer for assembly of the spring


38


on the agitator


27


.




The arm


32


(see

FIG. 12

) of the agitator


27


has a circular opening


46


. The arm


33


of the agitator


27


has a circular opening


47


.




The left end wall


17


(see

FIG. 2

) of the hopper


11


has an extension


50


(see

FIG. 1

) with a rectangular shaped post or pin


51


extending substantially perpendicular therefrom for disposition in the circular opening


47


in the arm


33


of the agitator


27


. The right end wall


18


(see

FIG. 2

) of the hopper


11


has an extension


52


with a rectangular shaped post or pin


53


extending substantially perpendicular therefrom for disposition in the circular opening


46


(see

FIG. 7

) in the arm


32


of the agitator


27


.




The shape of the post


53


(see FIG.


2


), which is the same as the shape of the post


51


(see FIG.


1


), is clearly shown in

FIG. 5

even though it is not actually disposed in the circular opening


47


in the arm


33


but is disposed in the circular opening


46


(see

FIG. 12

) in the arm


32


. This is because the left end wall


17


(see

FIG. 2

) of the hopper


11


including the extension


50


and the post


51


has been removed from FIG.


5


.




Accordingly, the agitator


27


is pivotally mounted for movement from the position of

FIG. 4

to the position of

FIG. 5

by the bar


20


(see

FIG. 2

) of the paddle


12


engaging the second portion


36


(see

FIG. 4

) of the extension


34


of the agitator


27


to move it to the position of FIG.


5


. When the curved portion


42


of the spring


38


engages interior surface


54


of the hopper


11


, the bar


20


(see

FIG. 2

) of the paddle


12


has ceased to engage the extension


34


of the agitator


27


.




Then, the spring


38


exerts a force of 20-50 grams on the agitator


27


to pivot it from the position of

FIG. 5

to the position of FIG.


4


. This results in the agitator


27


moving the toner through the exit opening, which is between the flat surface


23


of the rear wall


22


of the hopper


11


and the top wall


25


of the hopper


11


. This causes the toner to move along the downwardly inclined exit surface or wall


26


.




Thus, the agitator


27


prevents toner stagnation and delivers toner to a toner adder roller


55


(see FIG.


1


). The toner adder roller


55


is adjacent a developer roller


56


, which is adjacent a photoconductor drum


57


.




Accordingly, the spring


38


exerts the predetermined desired force on the agitator


27


to return it to its home position which is proximate the exit surface or wall


26


(see FIG.


4


). Instead of using the spring


38


, which is formed of music wire, a torsion spring


60


(see

FIG. 11

) may be employed, if desired, to return the agitator


27


(see

FIG. 5

) from the position of

FIG. 5

to the position of FIG.


4


.




The torsion spring


60


(see

FIG. 11

) includes a hooked end


61


for fitting around a surface


62


(see

FIG. 12

) of the arm


32


of the agitator


27


. The torsion spring


60


has a coiled portion


63


, which is supported on the post


53


(see FIG.


13


), surrounding the opening


46


in the arm


32


and a free end


64


(see FIG.


12


). As shown in

FIG. 13

, the free end


64


of the torsion spring


60


engages the interior surface


54


of the hopper


11


in the same manner as the curved portion


42


(see

FIG. 5

) of the spring


38


engages the interior surface


54


of the hopper


11


when the paddle


12


(see

FIG. 1

) has advanced the agitator


27


from the position of

FIG. 4

to the position of FIG.


5


.




Another resilient means for exerting the predetermined desired force on the agitator


27


to return the agitator


27


to the position of

FIG. 5

is to utilize a stamped and formed leaf spring


70


(see FIG.


14


). The leaf spring


70


has an elongated portion


71


extending from one end of a base


72


. The spring


70


has two fingers


73


and


74


spaced from each other and extending from the other end of the base


72


in a plane above the base


72


. A third finger


75


extends from the base


72


in a plane beneath the base


72


.




As shown in

FIG. 15

, the fingers


73


and


74


of the spring


70


extend across the top of the first body portion


28


of the agitator


27


while the third finger


75


extends beneath the first body portion


28


of the agitator


27


. Thus, this produces a press fit of the spring


70


on the first body portion


28


of the agitator


27


.




The base


72


is disposed in the middle of the three openings


31


between two of the connectors


30


. The base


72


of the spring


70


may be disposed in either of the other two openings


31


, if desired.




As shown in

FIG. 16

, the elongated portion


71


of the spring


70


has its end


76


disposed for engagement with the interior surface


54


(see

FIG. 5

) of the hopper


11


when the agitator


27


is moved to the position of

FIG. 5

by the paddle


12


(see FIG.


1


). This enables the spring


70


(see

FIG. 16

) to exert the predetermined desired force on the agitator


27


to return it to its home position.




The appropriate level of toner


77


(see

FIG. 4

) is schematically indicated by a surface line in

FIG. 4

, but the toner


77


is otherwise transparent for clarity purposes. The toner


77


is supplied to the interior of the hopper


11


through a fill hole


78


, which is closed by a plug.




For purposes of exemplification, exemplary embodiments of the invention have been shown and described according to the best present understanding thereof. However, it will be apparent that changes and modifications in the arrangement and construction of the parts thereof may be resorted to without departing from the spirit and scope of the invention.



Claims
  • 1. A toner cartridge comprising:a hopper having an opening for delivering toner out of said hopper; said hopper having a lower wall extending from a bottom of said hopper to a location substantially above the bottom of said hopper to define a bottom of said opening; a paddle rotatable in said hopper to stir toner such that some toner will move gently toward said opening; an exit surface to deliver toner from said hopper on the side of said lower wall opposite said hopper, said exit surface sloping downwardly during normal operation of said cartridge; an agitator extending across said exit surface having a first pivot member on one side of said exit surface and a second pivot member on an opposite side of said exit surface; said hopper having support pins for supporting said first pivot member and said second pivot member of said agitator to pivotally support said agitator on said hopper; said agitator normally located at a home position proximal said exit surface except when moved by said paddle around said first pivot member and said second pivot member; an extension on said agitator extending past said lower wall into the path of said paddle in said hopper when said paddle is rotated; and a spring mounted for exerting a force on said agitator to return said agitator to said home position after said agitator is moved from said home position by said paddle engaging said extension during rotation of said paddle and said paddle ceases to engage said extension.
  • 2. The toner cartridge according to claim 1 in which said spring is mounted on said agitator and has a portion engaging the interior of said hopper when said agitator is moved from said home position by said paddle engaging said extension during rotation of said paddle to exert force on said agitator to return said agitator to said home position.
  • 3. The toner cartridge according to claim 2 in which said spring is a wire having a free end constituting said portion engaging the interior of said hopper to exert force on said agitator to return said agitator to said home position after said paddle ceases to engage said extension.
  • 4. The toner cartridge according to claim 2 in which said spring is a wire having a base wrapped around said agitator and a leg extending from said base, said leg constituting said portion engaging the interior of said hopper to exert force on said agitator to return said agitator to said home position after said paddle ceases to engage said extension.
  • 5. The toner cartridge according to claim 2 in which said spring is a torsion spring connected to said agitator to exert force on said agitator and having a free end constituting said portion engaging the interior of said hopper when said agitator is moved from said home position by said paddle engaging said extension during rotation of said paddle to exert force on said agitator to return said agitator to said home position after said paddle ceases to engage said extension.
  • 6. The toner cartridge according to claim 2 in which said spring is a stamped and formed leaf spring having an end constituting said portion engaging the interior of said hopper when said agitator is moved from said home position by said paddle engaging said extension during rotation of said paddle to exert force on said agitator to return said agitator to said home position after said paddle ceases to engage said extension.
  • 7. The toner cartridge according to claim 6 in which said stamped and formed leaf spring comprises:a base having an elongated portion extending from one end thereof; said elongated portion having its free end constitute said end engaging the interior of said hopper; and said base having overlapping fingers in two substantially parallel planes extending from its other end for mounting on said agitator.
  • 8. The toner cartridge according to claim 1 in which said extension has its end contacting said lower wall when said agitator is in said home position.
  • 9. A toner cartridge comprising:a hopper having an opening for delivering toner out of said hopper; said hopper having a lower wall extending from a bottom of said hopper to a location substantially above the bottom of said hopper to define a bottom of said opening; a paddle rotatable in said hopper to stir toner such that some toner will move gently toward said opening; an exit surface to deliver toner from said hopper on the side of said lower wall opposite said hopper, said exit surface sloping downwardly during normal operation of said cartridge; an agitator extending across said exit surface having a first pivot member on one side of said exit surface and a second pivot member on an opposite side of said exit surface; said hopper having support pins for supporting said first pivot member and said second pivot member of said agitator to pivotally support said agitator on said hopper; said agitator normally located at a home position proximate said exit surface except when moved by said paddle around said first pivot member and said second pivot member; an extension on said agitator extending past said lower wall into the path of said paddle in said hopper when said paddle is rotated; and resilient means mounted on said agitator exerting a force on said agitator to return said agitator to said home position after said agitator is moved from said home position by said paddle engaging said extension during rotation of said paddle and said paddle ceases to engage said extension.
US Referenced Citations (5)
Number Name Date Kind
4993829 Naganuma et al. Feb 1991 A
5875378 Campbell et al. Feb 1999 A
6181904 Burdette et al. Jan 2001 B1
6229976 Kimura May 2001 B1
6459876 Buchanan et al. Oct 2002 B1
Foreign Referenced Citations (1)
Number Date Country
04-342274 Nov 1992 JP