[0001] The present invention relates to apparatus for metering powder from a container and
is especially, but not exclusively, useful in xerographic copier/duplicator types
of equipment.
[0002] It has been known for many years to transfer powder from a reservoir into a processing
area by means of a rotating roller which has flexible plates engaging the peripheral
surface of that roller to provide a dynamic seal. The powder can be entrapped by,
or adhered to the roller surface as the roller surface passes through the material
in the reservoir area, with this material being released by the roller after it has
passed beyond the containment defined by the peripheral edge engaging seal plates.
US. Patent Specification No. 3,114,482 shows such an arrangement.
[0003] Similar metering configurations have been adapted by the xerographic industry for
the purpose of dispensing toner from a container to the active developer area of the
copier. For instance, U.S. Patent Specification No. RE28,589 shows such an arrangement
wherein the toner transporting element comprises a roller having a series of longitudinal
peripheral grooves on its external surface. The toner is trapped in these grooves
and transported past the flexible sealing plates so as to be dropped into the active
developer sump for a copier. As the roller rotates, it imparts vibratory movement
to the sealing plates as they engage the peripheral grooves. This vibratory movement
assists in maintaining the mass of toner within the dispenser in a loose and pulverulent
state. The roller itself, however has little effect on the mass of toner.
[0004] Another similar device is shown in U.S. Patent Specification No. 3985098. In this
device, the roller is an auger feed device and has, at one end, a portion carrying
spaced projections. Toner is fed to the auger between a pair of sealing plates which
have projections positioned to be engaged by the projections on the roller. This engagement,
as the roller rotates, causes movement of the sealing plates to break up the tendency
for the toner to coalesce.
[0005] In yet another arrangement, shown in the Xerox Disclosure Journal, Vol. 1, No. 2,
Feb. 1974 at pages 61 and 62, the feed plates of a disposable toner carton are caused
to vibrate during operation of a toner disperser into which the carton fits. In this
system, a cam coupled for movement with the dispensing feed roller engages and drive
members coupled to the feed plates. This movement of the feed plates agitates the
developer in the dispenser. Other techniques employed in the past in an efford to
overcome this caking problem have enjoyed varying degrees of success. One method employed
is to maintain continuously moving stir paddles along the container wall. Another
is to employ vibratable screens or the like along the container wall, such as that
shown in U.S. Patent Specification No. 3,840,156. The caking problem mentioned is
discussed in U.S. Patent Specification No. 3,964,648 which endeavours to resolve it
by an arrangement radically different from the present invention in that it employs
a rotating rod that pivots within the cylindrical storage container and in proximity
to its walls so as to break up the cake and also to throw a portion of toner out of
the reservoir into the sump of the developer.
[0006] U.S. Patent Specification No. 4,044,719 shows an arrangement wherein a grooved, rotating
replenisher meter roll engages a spring-like plate so that the spring-like plate will
scrape loose any toner that has caked into the metering roll, but does not address
the resolution of the reservoir caking problem.
[0007] The present invention is directed to a system in which reservoir caking is reduced
by employing a metering roll which itself agitates powder in a container. Essentially,
it has been realised that if the roller is mounted eccentrically, it imparts vibrations
in the toner mass which extend beyond the toner in the immediate vicinity of the roller.
Additionally, these vibrations may be employed in conjunction with those imparted
by moving sealing plates.
[0008] According to the invention, there is provided powder dispensing apparatus comprising
a powder container including a lower wall portion biassed into sealing contact with
the surface of a rotatable metering roll positioned within the container but with
its lowermost surface portion outside, the metering roll surface having a section
configured to entrap a metered quantity of powder from the container as it passes
the wall portion and to discharge the metered quantity by gravity from the dispensing
apparatus as it leaves the wall portion, characterised in that the metering roll,
is mounted eccentrically relative to its axis of rotation so that, its surface imparts
vibratory motion to the powder in the container as the roll rotates, thereby to agitate
the powder to reduce caking therein.
[0009] The invention will now be described, by way of example, with reference to the accompanying
drawings, in which:
FIG. 1 is a partially sectioned side view of a developer for a copier/duplicator employing
a toner powder dispenser embodying the present invention;
FIG. 2 is a top view of the FIG. 1 apparatus;
FIG. 3 is an expanded detail view particularly showing the roll operation in the FIG.
1 and 2 structure;
FIG. 4 is a partially broken and sectioned view of the roll mounting and plate sealing
arrangement of the FIGS. 1-3 embodiment;
FIG. 5 is a partially broken and sectioned view of another embodiment of the present
invention;
FIG. 6 is a partially sectioned and broken view of yet another embodiment of the present
invention;
FIG. 7 is an expanded view illustrating the metering operation of the FIG. 6 embodiment;
FIG. 8 is an isometric view of an alternative arrangement for sealing the edge of
the flexible plates;
FIG. 9 is a sectioned and broken view of the flexible plate seal of FIG. 8 showing
its interrelationship to a sidewall; and
FIG. 10 is a sectioned and broken view of an alternative metering roll sealing configuration.
[0010] The various embodiments of the invention will be shown and described in conjunction
with the environment of the developer mechanism for a xerographic copier/duplicator.
As will be more apparent from the subsequent description, the structures used in these
examples cooperate to eliminate toner sticking or bridging to the sidewalls of a toner
replenisher chamber for a copier, thereby allowing relatively complete evacuation
of the toner from the replenisher chamber on demand by the developer.
[0011] In FIG. 1, a segment 10 of a photoconductive surfaced drum or a photoconductor belt
guide is shown in its generally operative relationship to the developer 12. The housing
for developer 12 includes an opening 15 in which a toner charging or loading device
can be attached. Thus, the toner is initially loaded and stored in replenisher chamber
16. The toner is metered from chamber 16 into the auger chamber 18, where it is added
to the developer mix which is transported along the lower portion of chamber 18 by
auger 19. Each end of divider wall 20 has an opening such as 21 with the mix entering
the developer chamber 22 through the opening at one end. Auger element 24 rotates
oppositely from auger 19 so that toner is forced through the opening at the opposite
end from chamber 22 through the opening at the opposite end of wall 20, thereby continuously
recirculating the mix between chamber 18 and 22 through the interconnecting ports
or openings such as 21.
[0012] The mix contained in chamber 22 is attracted to the surface of magnetic developer
roll 25 for ultimate contact against the photoconductive surface of drum or belt guide
10 to provide development of the image on the photoconductive surface of 10. The operation
of this mechanism is conventional.
[0013] Inside replenisher chamber 16 is a metering roll 30, which is mounted on shaft 32
for rotation eccentrically relative to the central axis of roll 30. Chamber 16 also
includes bar 35 which, as can be seen in FIGS. 1 and 2, extends through the sidewalls
of chamber 16 with outer end 36 being positioned to ride on the upper surface of a
cam 37 (see FIG. 2). Microswitch 38 is located so as to be actuated by arm 36 of rod
35 when the level of toner in chamber 16 has dropped below some minimum. Each time
that shaft 32 is rotated, cam 37 likewise rotates, lifting arm 36 and allowing rod
35 to drop onto the upper surface of the toner contained in chamber 16, thereby ensuring
that rod 35 is always following the surface level of the toner contained in chamber
16. Note that rod 35 functions as a combination toner level sensor and toner agitator
in that the inner segment 39 pivots along the wall inside chamber 16, thus augmenting
the loosening of toner from the housing sidewall as the toner level drops.
[0014] A flexible plate 40, forming a lower wall portion of the container and fabricated
from spring steel or the like, is mounted as shown in FIGS. 1 and 3. That is, plate
40 is formed with a bend so as to be insertable between the retainer 41 and nub 42
of centre wall 20. This arrangement ensures that plate 40 is biased toward the peripheral
surface of roll 30 and maintains constant engagement therewith during full rotation
of roll 30. The dashed position of plate 40 as shown at 44, is obtained as roll 30
rotates in the direction indicated by the arrows. Roll 30 has grooves or flat areas
45 separated by one or more peripheral bridges 46. In the example shown, two grooves
45A and 45B, formed by flat cuts, are separated by bridges 46A, 46B, and 46C. As roll
30 rotates eccentrically around shaft 32, the grooves 45 entrap toner which is transported
past the outer edge of blade 40 and allowed to drop into the auger chamber 18. Bridges
46 prevent the outer edge of blade 40 from scraping the toner out of the entrapment
areas 45 as it passes the leading edge 47 of plate 40.
[0015] On the opposite or outer wall 48, another flexible blade or plate 50 forming another
lower wall portion of the container is mounted and retained within nubs 51 and 52
in a manner somewhat similar to blade 40. That is, the spring-like nature of blade
50 and its attachment between nubs 51 and 52 causes blade 50 to be continuously biased
toward the peripheral surface of roll 30 so that outer edge 53 remains in continuous
contact with the surface of roll 30. Accordingly, blade or plate 50 flexes to the
position shown in dashed lines at 54, and outer edge 53 not only ensures that the
toner contained in chamber 16 does not escape, but also provides a scrubbing function
to loosen any toner adhering to the peripheral surface of roll 30 to cause it to drop
into the auger sump 18. The result of the eccentric movement of roll 30 through chamber
16, as well as the flexing action of spring plates 40 and 50 in response to rotation
of metering roll 30 is that the toner contained within replenisher chamber 16 vibtates,
thereby preventing it from sticking or bridging on the housing sidewalls 20 and 48.
This augments complete evacuation of replenisher chamber 16. In effect, blade 40 acts
as a metering spring in conjunction with roll 30, whereas blade 50 acts as a cleaning
spring, although both provide continuous sealing.
[0016] FIG. 4 illustrates a typical arrangement for sealing the mechanical mounting or roll
30, relative to sidewall 55. Sidewall 55 is constructed with a slight depression therein,
into which a sponge-like member 56 is bonded or otherwise secured with member 56 being
fabricated from any acceptable closed cell material such as polyurethane or the like.
Rotational power to roll 30 is coupled through shaft 32, which is further mounted
within collar 57. The compressible nature of member 56 allows it to maintain a sealed
relation with the end face of roll 30 so that toner will not migrate through the mounting
hole for shaft 30 through sidewall 55 and collar assembly 57. The resilient sealing
member 56 also engages the outer edges of flexible plates 40 and 50 to prevent escape
of toner from chamber 16. That is, the bead on the outer edges of plates 40 and 50
somewhat compress member 56 in a manner similar to roll 30, thereby completing the
seal of chamber 16 despite the flexing movement of plates 40 and 50. This interrelationship
can be seen in FIGS. 1, 3, and 4.
[0017] In operation, power from a source (not shown) is applied to shaft 59 (note FIG. 2).
Clutch 58 is operable in response to electrical or mechanical actuation to couple
the rotary power from shaft 59 to shaft 32 and thus, to roll 30. The typical controls,
having determined by whatever means that additional toner is to be metered from replenisher
chamber 16, causes clutch 58 to be actuated and one or more rotations of roll 30 to
be accomplished until the controls determine that adequate toner has been dispensed.
In the course of rotation of roll 30, toner is entrapped in grooves 45 on roll 30,
transported past the sealing flexible wall portion or plate 40, and disgorged into
auger chamber 18 with the further assistance of scraper edge 53 on flexible wall portion
or plate 50. Plates 40 and 50 oscillate between the positions shown in FIG. 3, maintaining
continuous jostling or jogging of the toner contained within chamber 16. Cam 37 likewise
causes level sensor bar 35 to reciprocate to aid in sidewall build-up prevention and
level sensing of the amount of toner contained within chamber 16.
[0018] A somewhat different embodiment of the present invention is illustrated in FIG. 5,
wherein the replenisher chamber 70 is shown with a charge of toner 71 contained therein.
The combination toner level sensor and toner agitator 72 is here shown with a somewhat
open grid configuration, but pivotable around shaft 74, which has an arm external
to chamber 70 for actuating a microswitch, in response to a cam movement similar to
that discussed previously for level sensor bar 35. The generally triangular shape
of the lateral members such as 73 aids both in assuring that sensor 72 is brought
to rest on the top of the toner and in breaking up the toner lumps as it is dropped
into chamber 70.
[0019] The eccentrically mounted metering roll 75 is sealed with a metering spring-type
of plate or blade 76 on one side, and a cleaning spring-type of blade 77 on the other,
also in a manner somewhat analogous to that previously described, at least as far
as mountings thereof relative to sidewalls 78 and 79. Roll 75 has a continuous longitudinal
groove 80 therein, without any bridging since groove 80 will entrap toner within itself
and blade plate 76 seals the mouth of groove 80 as it passes from chamber 70 to the
auger chamber 81. In this case, the outer edge 82 of blade plate 77 is arranged so
as to enter groove 80 and assure scrubbing of any toner from groove 80 before it reenters
chamber 70.
[0020] Yet another arrangement is shown in FIGS. 6 and 7 wherein the toner within chamber
86 is sensed by toner level arm 88, having a single inverted V-shaped transverse arm
89 for resting on the top of the toner and also aiding in lump break-up. The eccentrically
mounted metering roll 90 has an oval shaped cross-section in this example and interfaces
with spring blades or plates 91 and 92 in a manner similar to that previously described.
However, eccentrically mounted roll 90 has an outwardly extending ridge or raised
metering boss 95 thereon for the purpose of metering toner past sealing blade plate
91 with plate 92 acting as a scraper as is shown in detail in FIG. 7. The toner in
reservoir chamber 86 oscillates vertically in accordance with arrows 96 and 97 in
response to rotation of metering roll 90. The noncircular cross-section of metering
roll 90 adds a churning effect to the toner in the replenisher chamber as roll 90
rotates.
[0021] An alternative arrangement for sealing the replenisher storage chamber relative to
the sidewalls is illustrated in FIGS. 8 and 9. Flexible plate 100 is similar in construction
and operation to the metering and cleaning blades 40 and 50 of FIGS. 1 and 3. Blade
100 is sealed relative to sidewall 101 by a resilient sealing pad 102. Pad 102 is
made of a compressible material such as polyurethane foam with a pressure sensitive
adhesive surface for adhering in wrapped relation around the edge of plate 100. Thus,
compression of the wrapped edge of pad 102 establishes a dynamic seal interface 103
with sidewall 101 to prevent escape of toner despite flexing movement of spring plate
100.
[0022] FIG. 10 shows a configuration for sealing the metering roll 104 relative to sidewall
101 in a manner suitable for use concurrently with FIGS. 8 and 9. Roll 104 is mounted
for eccentric rotation by drive shaft 105 coupled to a power source (not shown) on
the other side of sidewall 101. Sealing assembly 106 is formed of a compressible core
107 which is affixed to roll 104 by bonding or adhering at interface 108 as by a pressure
sensitive adhesive or the like. The opposite side of seal assembly 106 is formed by
a wear-resistant layer 109 such as Mylar (trademark of E. I. DuPont de Nemours Et
Co.). Seal assembly 106 is installed in a generally compressed relation on the end
of metering roll 104 and remains in compressed relation between roll 104 and sidewall
101 during the full rotational operation of roll 104. Accordingly, toner is prevented
from escaping from the storage chamber into either the developer sump or the mounting
hole for drive shaft 105.
[0023] Note that the reciprocating motion of the metering roll surfaces as shown in the
preferred embodiments imparts some pulsating motion to the reservoir toner independent
of the flexible plates. Thus, the flexible plates can be replaced by relatively rigid
plates mounted and biased for a plunger type of movement toward the metering roll
surface. The combination of the spring-like flexible plates and the eccentric movement
of the metering roll surface in accordance with the preferred embodiments is advantageous
in that the greatest amount of agitation of the toner in the replenisher chamber is
obtained.
1. Powder dispensing apparatus comprising a powder container including a lower wall
portion (40, 50) biassed into sealing contact with the surface of a rotatable metering
roll (30) positioned within the container but with its lowermost surface portion outside,
the metering roll surface having a section (45) configured to entrap a metered quantity
of powder from the container as it passes the wall portion and to discharge the metered
quantity by gravity from the dispensing apparatus as it leaves the wall portion, characterised
in that the metering roll is mounted eccentrically relative to its axis of rotation
so that its surface imparts vibratory motion to the powder in the container as the
roll rotates, thereby to agitate the powder to reduce caking therein.
2. Apparatus as claimed in claim 1 further characterised in that said roll has a substantially
circular cross secton.
3. Apparatus as claimed in claim 1 characterised in said roll has a non-circular cross
section.
4. Apparatus as claimed in any of claims 1 to 3 further characterised in that said
lower wall portion (40) is formed from resilient material and is biassed into contact
with the roll such as to vibrate as the roll rotates to impart further vibratory motion
to the powder in the container.
5. Apparatus as claimed in any of the previous claims further characterised by a further
lower wall portion (50) biassed into sealing contact with the surface of the roll,
the wall portions defining the edges of said lowermost surface portion of the roll,
said further lower wall portion being of resilient material such as to vibrate as
the roll rotates to impart further vibratory motion to the powder in the container.
6. Apparatus as claimed in any of the previous claims further characterised in that
said section of the metering roll surface includes an indentation (45) to retain powder
and a bridge (46) over the indentation over which the, or each, lower wall portion
rides.
7. Apparatus as claimed in any of claims 1 to 5 further characterised in that said
section of the metering roll includes a projection (95) over which the, or each, lower
wall portion rides.
8. Apparatus as claimed in any of the previous claims, further characterised in that
the metering roll and the, or each, wall portion extends over substantially the length
of the container.
9. Apparatus as claimed in any of the previous claims, further characterised in that
said container comprises the toner dispenser of the developer unit of a xerographic
copier, and toner is dispensed therefrom by the metering roll into the developer sump
of the developer unit.
1. Dispositif distributeur de poudre comportant un conteneur pour la poudre, possédant
un élément de paroi inférieur (40, 50) sollicité de manière à être en contact étanche
avec la surface d'un rouleau doseur rotatif (30) disposé à l'intérieur du conteneur
mais dont la partie de sa surface la plus basse est à l'extérieur, le rouleau doseur
comportant un élément de surface (55) conformé de manière à retenir une quantité dosée
de poudre provenant du conteneur, lorsque l'élément de surface passe devant l'élément
de paroi, et à évacuer la quantité dosée du dispositif distributeur sous l'effet de
la pesanteur lorsqu'elle quitte l'élément de paroi, caractérisé en ce que le rouleau
doseur est monté de façon excentrée par rapport à son axe de rotation de telle sorte
que sa surface applique un mouvement vibratoire à la poudre située dans le conteneur,
lorsque le rouleau tourne, de manière à agiter ainsi la poudre afin de réduire l'agglomération
au son intérieur.
2. Dispositif selon la revendication 1, caractérisé en outre en ce que ledit rouleau
possède une section transversale essentiellement circulaire.
3. Dispositif selon la revendication 1, caractérisé en outre en ce que ledit rouleau
possède une section transversale non circulaire.
4. Dispositif selon l'une quelconque des revendications 1 à 3, caractérisé en outre
en ce que ledit élément de paroi inférieur (40) est réalisé en un matériau élastique
et est sollicité de manière à être en contact avec le rouleau de manière à vibrer
lorsque le rouleau tourne afin d'appliquer un mouvement vibratoire supplémentaire
à la poudre située dans le conteneur.
5. Dispositif selon l'une quelconque des revendications précédentes, caractérisé en
outre par un autre élément de paroi inférieur (50) solicité de manière à être en contact
étanche avec la surface du rouleau, les éléments de paroi définissant les bords de
ladite partie de surface la plus basse du rouleau, ledit autre élément de paroi inférieur
étant constitué en un matériau élastique de manière à vibrer lorsque le rouleau tourne
afin d'appliquer un mouvement vibratoire supplémentaire à la poudre située dans le
conteneur.
6. Dispositif selon l'une quelconque des revendications précédentes, caractérisé en
outre en ce que ledit élément de surface de la surface du rouleau doseur comporte
un renfoncement (45) destiné à retenir la poudre et un rebord (46) en saillie sur
le renfoncement et sur lequel circule le ou chaque élément de paroi inférieur.
7. Dispositif selon l'une quelconque des revendications 1 à 5, caractérisé en outre
en ce que ledit élément de surface du rouleau doseur comporte une partie saillante
(95) sur laquelle circule le ou chaque élément de paroi inférieur.
8. Distributeur selon l'une quelconque des revendications précédentes, caractérisé
en outre en ce que le rouleau doseur et le ou chaque élément de paroi s'étendent sur
essentiellement la longueur du conteneur.
9. Distributeur selon l'une quelconque des revendications précédentes, caractérisé
en ce que ledit conteneur comporte le distributeur de toner de l'unité de développement
d'un copieur xérographique, et que le toner est distribué par le rouleau doseur à
partir de cette unité dans la cuvette de développement de l'unité de développement.
1. Pulverabgabevorrichtung mit einem Pulverbehalter, welcher einen unteren Wandabschnitt
(40, 50) enthält, der in dichtende Berührung mit der Oberfläche einer drehbaren Zumeßwalze
(30) vorbelastet ist, die innerhalb des Behälters, aber mit ihrem untersten Oberflächenabschnitt
außerhalb angeordnet ist, wobei die Zumeßwalze einen so ausgebildeten Abschnitt (45)
aufweist, daß er beim Vorbeilaufen am Wandabschnitt eine bemessene Menge des Pulvers
aus dem Behälter einfängt und beim Verlassen des Wandabschnitts die bemessene Menge
durch Schwerkraft aus der Abgabevorrichtung entlädt, dadurch gekennzeichnet, daß die
Zumeßwalze exzentrisch bezüglich ihrer Drehachse angebracht ist, so daß ihrer Oberfläche
bei Drehung der Walze dem Pulver im Behälter eine Schwingungsbewegung verleiht, wodurch
das Pulver gerührt und ein Verklumpen desselben gemindert wird.
2. Vorrichtung nach Anspruch 1, ferner dadurch gekennzeichnet, daß die Walze einen
im wesentlichen kreisförmigen Querschnitt hat.
3. Vorrichtung nach Anspruch 1, ferner dadurch gekennzeichnet, daß die Walze einen
nicht-kreisförmigen Querschnitt hat.
4. Vorrichtung nach irgendeinem der Ansprüche 1 bis 3 ferner dadurch gekennzeichnet,
daß der untere Wandabschnitt (40) aus elastischem Material ausgebildet und in Berührung
mit der Walze vorbelastet ist, so daß er bei Drehung der Walze schwingt und dem Pulver
im Behälter eine weitere Schwingungsbewegung verleiht.
5. Vorrichtung nach irgendeinem der vorstehenden Ansprüche, ferner gekennzeichnet
durch einen in dichtende Berührung mit der Oberfläche der Walze vorbelasteten weiteren
unteren Wandabschnitt (50), wobei die Wandabschnitte die Ränder des untersten Oberflächenabschnitts
der Walze bestimmen, wobei der weitere untere Wandabschnitt aus elastischem Matrial
ist, so daß er bei Drehung der Walze schwingt und dem Pulver im Behälter eine weitere
Schwingungsbewegung verleiht.
6. Vorrichtung nach irgendeinem der vorstehenden Ansprüche, ferner dadurch gekennzeichnet,
daß der Abschnitt der Zumeßwalzenoberfläche eine Einsenkung (45) zur Aufnahme von
Pulver und eine Brücke über die Einsenkung, über welche sich der oder jeder untere
Wandabschnitt aufliegend bewegt, enthält.
7. Vorrichtung nach irgendeinem der Ansprüche 1 bis 5, ferner dadurch gekennzeichnet,
daß der Abschnitt der Zumeßwalze einen Vorsprung (95) enthält, über welchen sich der
oder jeder untere Wandabschnitt aufliegend bewegt.
8. Vorrichtung nach irgendeinem der vorstehenden Ansprüche, ferner dadurch gekennzeichnet,
daß die Zumeßwalze und der oder jeder Wandabschnitt sich im wesentlichen über die
Länge des Behälters erstrecken.
9. Vorrichtung nach irgendeinem der vorstehenden Ansprüche, ferner dadurch gekennzeichnet,
daß der Behälter die Tonerabgabe der Entwicklereinheit eines xerographischen Kopiergeräts
umfaßt und daß Toner daraus durch die Zumeßwalze in den Entwicklersumpf der Entwicklereinheit
abgegeben wird.