Mechanism for opening/closing a toner falling aperture

A mechanism for opening/closing a toner falling aperture is adapted to open/close a toner falling aperture formed in the bottom of a toner cartridge main body in which toner is housed. Disposed inside of the toner cartridge main body is a screw conveyor for conveying the toner to the toner falling aperture. While the toner cartridge is not under use, an elastic sealing member attached to the top surface of the bottom of the toner cartridge main body, closes the toner falling aperture. One end of the sealing member is secured to the screw conveyor. When the toner cartridge is set to a predetermined portion of the main body of an image forming apparatus and the screw conveyor is driven, the screw conveyor takes up the sealing member while winding the same thereon, thus opening the toner falling aperture. The sealing member to which toner is sticked, is taken up by the screw conveyor and held inside of the toner cartridge main body.

CROSS REFERENCE TO RELATED APPLICATION 
This Application claims priority benifit under 35 USC section 119 of 
Japanese Patent Application Serial No. 4-3482415, filed on Dec. 28, 1992 
and No. 5-2745, filed on Jan. 11, 1993, the disclosures of which are 
incorporated by reference. 
BACKGROUND OF THE INVENTION 
The present invention relates to a mechanism for opening/closing a toner 
falling aperture through which toner is supplied from a toner cartridge to 
the developing device in an image forming apparatus such as an 
electrostatic copying apparatus, a facsimile, a laser beam printer or the 
like. 
In the image forming apparatus above-mentioned, a toner cartridge is 
removably attached to a housing concave in the main body of the image 
forming apparatus. A toner cartridge of which toner has been used up, is 
to be replaced with a new toner cartridge. 
Generally, a toner cartridge has a sealing member made of an elastic sheet 
which removably covers, at the outer surface of the main body of the toner 
cartridge, a toner falling aperture formed in the bottom of the toner 
cartridge main body in which toner is housed. After the toner cartridge 
has been set to the housing concave, the sealing member is torn off, 
causing the toner falling aperture to be opened. Then, toner falling 
through the toner falling aperture, is supplied to the developing device 
which is disposed under the toner falling aperture. The sealing member 
thus torn off, is separated from the toner cartridge and taken out to the 
outside of the main body of the image forming apparatus. This 
disadvantagesouly presents the problem that the toner stuck to the sealing 
member scatters inside and outside of the main body of the image forming 
apparatus. 
On the other hand, there is proposed an image forming apparatus having an 
opening/closing mechanism for opening/closing a toner falling aperture 
formed in the bottom of the main body of a toner cartridge. Further, the 
developing device may be made in the form of a unit and adapted to be 
inserted in and removed from a housing concave of the main body of an 
image forming apparatus. In this connection, there is proposed an image 
forming apparatus having an opening/closing mechanism for opening/closing 
a toner falling aperture formed in the top surface of the developing unit. 
Conventionally, the opening/closing mechanism of the developing unit is 
operated irrespectively of the operation of the opening/closing mechanism 
of the toner cartridge. This produces a difference in toner falling 
aperture opening/closing timing between the opening/closing mechanisms. 
This may cause toner to fall in the space between the opposite surfaces of 
the developing unit and the toner cartridge (between the top surface of 
the developing unit and the underside of the toner cartridge). This 
involves the likelihood that the falling toner scatters at the time when 
the toner cartridge is pulled out. 
SUMMARY OF THE INVENTION 
In view of the foregoing, the present invention is proposed with the object 
of providing an economical mechanism for opening/closing a toner falling 
aperture, which prevents toner from scattering. 
To achieve the object above-mentioned, the present invention provides, as a 
first aspect, a mechanism for opening/closing a toner falling aperture 
formed in the bottom of the main body of a toner cartridge in which toner 
is housed, comprising: an elastic sealing member which is disposed inside 
of the toner cartridge main body and which is removably attached to the 
top surface of the bottom for closing the toner falling aperture; and 
taking-off means which is disposed inside of the toner cartridge main 
body, to which an end of the sealing member is secured, and which is 
adapted to take off the sealing member while winding the same thereon when 
the taking-off means is driven by o an external driving source. 
According to the arrangement above-mentioned, the toner cartridge which has 
not been used yet, is mounted on the main body of an image forming 
apparatus, and the taking-off means is then driven by the external drive 
source, so that the sealing member is wound on the taking-off means, 
causing the sealing member to be stripped off from the bottom of the toner 
cartridge main body. This causes the toner falling aperture to be opened. 
The sealing member to which toner is stuck, is taken up by the taking-off 
means and held inside of the toner cartridge main body. This prevents 
toner from scattering outside of the toner cartridge when the toner 
cartridge is replaced. 
The taking-off means may comprise rotary toner delivery means for 
delivering toner housed inside of the toner cartridge main body, toward 
the toner falling aperture. The rotary toner delivery means may comprise a 
screw conveyor. 
Preferably, the sealing member is a tape-like member. In such an 
arrangement, even though the sealing member is wound on a part of the 
rotary toner delivery means, no adverse effect is substantially exerted to 
the performance of the toner delivery means. 
The present invention provides, as another aspect, a mechanism for 
opening/closing a toner falling aperture, applied to an image forming 
apparatus having: a developing unit main body removably set to a housing 
concave in the main body of the image forming apparatus; a toner cartridge 
main body slidably connected to the top surface of the developing unit 
main body and removably set to the housing concave or cavity; and upper 
and lower toner falling apertures respectively formed in the bottom of the 
toner cartridge main body and in the top surface of the developing unit 
main body, the apertures being adapted to communicate with each other: the 
mechanism for opening/closing a toner falling aperture comprising: an 
upper shutter member slidably disposed under the bottom of the toner 
cartridge main body for opening/closing the upper toner falling aperture; 
first biasing means for biasing the upper shutter member to close the 
upper toner falling aperture; a lower shutter member slidably disposed on 
the top surface of the developing unit main body for opening/closing the 
lower toner falling aperture; second biasing means for biasing the lower 
shutter member to close the lower toner falling aperture; first engaging 
means disposed at the lower shutter member and adapted to be engaged with 
an engaging portion of the main body of the image forming apparatus such 
that the lower shutter member opens the lower toner falling aperture when 
the developing unit main body is inserted into the housing concave; and 
second engaging means respectively disposed at the upper shutter member 
and the lower shutter member for engaging the upper and lower shutter 
members with each other. 
According to the arrangement above-mentioned, when the toner cartridge main 
body alone is inserted into the image forming apparatus in which the 
developing unit main body has been set in the housing concave and in which 
the lower toner falling aperture has been opened, the second engaging 
means are engaged with each other, causing the upper shutter member to 
open the upper toner falling aperture. When the toner cartridge main body 
alone is pulled out, the second engaging means are disengaged from each 
other so that the first biasing means causes the upper shutter member to 
automatically close the upper toner falling aperture. This prevents toner 
from scattering. 
When the toner cartridge main body and the developing unit main body are 
integrally inserted into the housing concave of the main body of the image 
forming apparatus, the engagement of the first engaging means causes the 
lower shutter member to open the lower toner falling aperture and the 
engagement of the second engaging means with each other causes the upper 
shutter member to open the upper toner falling aperture in association 
with the opening of the lower toner falling aperture. When the toner 
cartridge main body and the developing unit main body are integrally 
pulled out, the disengagement of the first engaging means causes the first 
and second biasing means to automatically close the upper and lower toner 
falling apertures. 
Provision is made such that the upper and lower shutter members are 
interlockingly operated. This not only provides simplification of the 
structure and reduction in production cost, but also prevents toner from 
scattering due to difference in opening/closing timing between the upper 
and lower shutter members. 
Preferably, the toner cartridge main body and the developing unit main body 
are relatively slidable with respect to each other by a pair of slide 
mechanisms including grooves and projecting members which are adapted to 
be engaged with each other, and the second engaging means are disposed 
between the bottom of the toner cartridge main body and the top surface of 
the developing unit main body and between the pair of slide mechanisms. If 
the second engaging means cross the grooves, it is difficult to seal the 
groove portions that the second engaging means cross. According to the 
present invention, however, the second engaging means do not cross the 
grooves and the like. It is therefore easy to seal the space between the 
bottom of the toner cartridge main body and the top surface of the 
developing unit main body. 
Preferably, the mechanism for opening/closing a toner falling aperture 
further comprises: a first stopper disposed at a predetermined part of the 
housing concave for stopping, at a predetermined insertion stroke 
position, the toner cartridge main body which is inserted; and a second 
stopper disposed at a predetermined part of the housing concave for 
stopping, at a predetermined insertion stroke position, the developing 
unit main body which is inserted: and the positions where the developing 
unit main body and the toner cartridge main body are stopped by the 
respective stoppers, are different from each other such that the lower 
shutter member opens the lower toner falling aperture before the upper 
shutter member opens the upper toner falling aperture and that the upper 
shutter member closes the upper toner falling aperture before the lower 
shutter member closes the lower toner falling aperture when the developing 
unit main body and the toner cartridge main body connected thereto are 
integrally inserted in and removed from the housing concave. 
According to the arrangement above-mentioned, the lower shutter member 
opens the lower toner falling aperture before the upper shutter member 
opens the upper toner falling aperture, and the upper shutter member 
closes the upper toner falling aperture before the lower shutter member 
closes the lower toner falling aperture. This securely prevents toner from 
scattering between the opposite surfaces of the toner cartridge main body 
and the developing unit main body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The following will discuss in detail embodiments of the present invention 
with reference to the attached drawings. 
First Embodiment 
FIGS. 1 to 4 show a first embodiment of the present invention. 
Referring to FIG. 3, a copying apparatus has, inside of the main body 1 
thereof, (i) an optical system 3 where a document placed on a document 
placing plate 2 is illuminated and scanned, and light reflected from the 
document is guided to a photoreceptor drum 42, (ii) an image forming unit 
4 where an electrostatic latent image formed on the photoreceptor drum 42 
is converted into a toner image by a developing device 41, and the toner 
image is then transferred onto a paper sheet, and (iii) a paper delivery 
unit 5 where a paper sheet is pulled out from a paper feeding tray 61 in a 
paper housing portion 6 by a paper feeding roller 51 having a semicircular 
section, and the paper sheet is passed through the image forming unit 4 
and then discharged to a discharge tray 56 inside of the main body of the 
copying apparatus. 
With reference to FIG. 1, removably mounted on the main body 1 of the 
copying apparatus is a toner cartridge TC for supplying toner to the 
developing device 41. A mechanism for opening/closing a toner falling 
aperture according to an embodiment of the present invention, is 
characterized in that a sealing member S which closes a toner falling 
aperture TC2 in the toner cartridge TC, is adapted to be taken up by a 
screw conveyor SC, serving as rotary delivery means, disposed inside of 
the toner cartridge TC, as shown in FIG. 4. 
Referring to FIG. 3, the copying apparatus main body 1 has a lower unit 7 
partitioned by a lower casing 71, and an lapper unit 8 partitioned by an 
upper casing 81 supported in a manner rotatable around a predetermined 
axis of rotation m at the lower end thereof, the upper unit 8 being 
relatively rotatable with respect to the lower unit 7. The copying 
apparatus main body 1 is of a so-called clamshell type in which the upper 
unit 8 is rotatably opened/closed with respect to the lower unit 7. 
The optical system 3 is arranged such that a document is illuminated by a 
fluorescent lamp 39 having a reflector plate 38 secured to a first moving 
frame 3A, and light reflected from the document is guided to the 
photoreceptor drum 42 after successively passing through a first mirror 31 
secured to the first moving frame 3A, second and third mirrors 32, 33 
secured to a second moving frame 3B, a lens 37, fourth and fifth mirrors 
34, 35 secured to a third moving frame 3C, and a sixth mirror 36. 
In the image forming unit 4, there are successively disposed, around the 
photoreceptor drum 42, a corona discharger 43, the developing device 41, a 
transferring corona discharger 44 and a cleaning device 45 in this order. 
The image forming unit 4 is arranged such that a document image is formed 
to form an electrostatic latent image on the outer peripheral surface of 
the photoreceptor drum 42 uniformly electrically charged by the corona 
discharger 43, the electrostatic latent image is converted into a toner 
image by the developing device 41, the toner image is transferred to paper 
by the transferring corona discharger 44, and residual toner is collected 
by the cleaning device 45. 
The paper delivery unit 5 comprises: the paper feeding roller 51 adapted to 
pull out paper, one by one, from the paper feeding tray 61; a delivery 
roller 52 for delivering paper from a manual paper feeding part 60 or the 
paper feeding tray 61; resist means 53 with which the tip of paper 
delivered by the delivery roller 52 comes in contact, causing the paper to 
temporarily wait, the resist means 53 being formed by driving roller means 
53a and driven roller means 53b; a fixing unit 54 for fixing a toner image 
transferred onto paper; and a pair of discharging roller means 55. 
Referring to FIGS. 1 and 2, the toner cartridge TC comprises: a 
container-like toner cartridge main body T1; an aperture TC2 which is 
formed in the tom TC1 of the toner cartridge main body T1 and through 
which toner is adapted to fall toward the developing device 41; a pair of 
screw conveyors SC disposed inside of the toner cartridge main body T1 in 
the longitudinal direction thereof; and the tape-like narrow sealing 
member S having one end S1 which closes the aperture TC2 at the inside of 
the toner cartridge main body T1 while the toner cartridge TC is not under 
use. The other end S2 of the sealing member S is secured to a spiral blade 
SC1 of one screw conveyor SC. The sealing member S is stuck to the edge of 
the aperture TC2 by heat fusion or the like. 
The screw conveyors SC are adapted to be rotated in opposite directions 
(See arrows shown by chain lines in FIG. 1) to feed toner in opposite 
direcitons (See white arrows in FIG. 2). This causes toner to be 
circulated while passing on the aperture TC2 inside of the toner cartridge 
main body T1. 
The toner cartridge main body T1 is provided at the pulling-side end 
thereof with a channel-like movable grip T2. The grip T2 can be housed in 
a recess portion T3 formed at the pulling-side end such that the grip T2 
does not project from the pulling-side end when the grip T2 is not under 
use. 
According to the embodiment above-mentioned, when the toner cartridge TC 
which has not been used yet, is mounted on the copying apparatus main body 
1 and the screw conveyors SC are rotatingly driven, the sealing member S 
is taken up by one of the screw conveyors SC under rotation. This causes 
the sealing member S to be torn off from the aperture TC2, thus opening 
the aperture TC2 (See FIG. 4). The sealing member S to which toner is 
stuck, is taken up inside of the toner cartridge main body T1. This 
prevents toner from scattering outside of the toner cartridge TC when the 
toner cartridge TC is replaced. Accordingly, no toner scatters inside and 
outside of the copying apparatus main body 1 when the toner cartridge TC 
is replaced. 
The sealing member S is in the form of a narrow tape. Accordingly, even 
though the sealing member S is wound on a portion of the screw conveyor 
SC, no adverse effect is substantially exerted on the delivery performance 
of the screw conveyor SC. 
Second Embodiment 
Instead of the screw conveyors used in the embodiment in FIG. 1, there may 
be used a toner stirring and delivery mechanism DM as shown in FIG. 5. In 
the toner stirring and delivery mechanism DM, a plurality of rotary 
plate-like stirring blades DM1 and the like are disposed in the toner 
delivery direction so that toner is stirred and delivered. In such an 
arrangement, too, a sealing member S can be taken up by one of the 
stirring blades DM1, and similar effects to those produced in the 
embodiment in FIG. 1, can be produced. 
Third Embodiment 
With reference to FIG. 6A to FIG. 15C, the following will discuss a further 
embodiment of the present invention. 
Referring to FIG. 7, a developing device 41 is arranged in the form of an 
integral developing unit GU, and toner is to be supplied by a replaceable 
toner cartridge TC. Other component elements in FIG. 7 are similar to 
those shown in FIG. 3. Thus, like parts in FIG. 7 are designated by like 
reference numerals used in FIG. 3, and the description thereof is here 
omitted. 
With reference to FIG. 8, a copying apparatus is arranged such that the 
developing unit GU and the toner cartridge TC are integrally or 
individually inserted in and removed from a predetermined part of the 
copying apparatus main body 1 (the inserting direction is shown by K1, 
while the removing direction is shown by K2). As shown in FIGS. 6A, 6B, 
6C, an upper shutter member US and a lower shutter member SS are disposed 
for opening/closing a toner falling aperture TC2 of the toner cartridge TC 
and a toner falling aperture GU2 of the developing unit GU, respectively, 
and are adapted to be interlockingly operated. When inserted, the 
developing unit GU and the toner cartridge TC are stopped when the 
insertion-side ends thereof come in contact with a stopper L (See FIG. 6C) 
at a predetermined insertion stroke position. 
Referring to FIGS. 6A, 6B, 6C, FIG. 9, FIG. 10 and FIG. 11, the developing 
unit main body G1 has guide grooves GU3 in which both lateral edges of the 
lower shutter member SS are inserted. This enables the lower shutter 
member SS to be slid on the top surface GU1 of the developing unit main 
body G1. Further, the developing unit main body G1 has guide grooves GU4 
in which projections TC3 of the toner cartridge TC are inserted. This 
enables the toner cartridge TC to be slidably inserted in and removed from 
the developing unit GU. 
Referring to FIG. 10, the lower shutter member SS is made of a plate member 
and has a lower communicating aperture SS1 which is adapted to communicate 
with the aperture GU2 in the developing unit GU when the lower shutter 
member SS is slided to a predetermined position. The lower shutter member 
SS is provided on the top surface thereof with an upward projection SS2 
engageable with a groove US2 in the upper shutter member US. The lower 
shutter member SS is provided at the underside thereof with a downward 
projection SS3, serving as first engaging means, which passes through a 
slit GU5 in the top surface GU1 of the developing unit GU and which is 
engageable with a projection J1 of the copying apparatus main body 1. By a 
compression coiled spring FS serving as biasing means, the lower shutter 
member SS is normally biased toward the inserting direction K1 such that 
the aperture SS1 is positionally shifted toward the inserting direction K1 
with respect to the aperture GU2 in the developing unit GU. That is, the 
lower shutter member SS is biased to close the aperture GU2. 
When the downward projection SS3 of the lower shutter member SS is engaged 
with the projection J1 of the copying apparatus main body 1, the lower 
shutter member SS opens/closes the aperture GU2 in association with the 
insertion and removal of the developing unit GU. The groove US2 in the 
upper shutter member US and the lapward projection SS2 of the lower 
shutter member SS form second engaging means for interlockingly operating 
the upper and lower shutter members US, SS. 
Referring to FIGS. 11 to 14, the toner cartridge main body T1 is a box-like 
container. Slidably attached to the toner cartridge main body T1 is the 
upper shutter member US for opening/closing the toner falling aperture TC2 
formed in the bottom TC1 of the toner cartridge main body T1. The upper 
shutter member US has an upper communicating aperture US1 which is adapted 
to communicate with the aperture TC2 in the toner cartridge. TC when the 
upper shutter member US is slided to a predetermined position. Also, the 
upper shutter member US has the groove US2 engageble with the upward 
projection SS2 of the lower shutter member SS when the upper shutter 
member US is slided to a predetermined position. By a compression coiled 
spring FU serving as biasing means, the upper shutter member US is 
normally biased toward the inserting direction K1 such that the aperture 
US1 is positionally shifted toward the inserting direction K1 with respect 
to the aperture TC2 in the toner cartridge TC. That is, the upper shutter 
member US is biased to close the aperture TC2. 
The following will discuss the operation of the mechanism for 
opening/closing a toner falling aperture. 
First, with reference to FIGS. 15A, 15B, 15C, the description will be made 
of the case where only the developing unit GU is mounted. With the lower 
shutter member SS so biased as to close the aperture GU2, the developing 
unit GU is inserted into a predetermined part of the copying apparatus 
main body 1 (FIG. 15A). When the developing unit GU reaches the terminal 
end of an insertion stroke, the downward projection SS3 of the lower 
shutter member SS is engaged with the projection J1 of the copying 
apparatus main body 1 (FIG. 15B). This restrains the lower shutter member 
SS from being relatively moved with respect to the copying apparatus main 
body 1. When the developing unit GU is further inserted, the compression 
coiled spring FS is contracted and the developing unit GU is relatively 
moved with respect to the lower shutter member SS, so that the aperture 
GU2 in the developing unit GU is opened. At the same time, the developing 
unit GU is stopped as coming in contact with the stopper L (FIG. 15C). 
When removing the developing unit GU, the operations above-mentioned may 
be reversed. That is, the developing unit GU may be removed with the 
aperture GU2 closed by the lower shutter member SS. 
With reference to FIGS. 6A, 6B, 6C, the following description will discuss 
the case where the developing unit GU and the toner cartridge TC connected 
thereto are integrally inserted. With the developing unit GU connected to 
the toner cartridge TC, the groove US2 in the upper shutter member US is 
engaged with the upward projection SS2 of the lower shutter member SS, and 
the apertures US1, SS1 in the both upper and lower shutter members US, SS 
communicate with each other. 
When the developing unit GU and the toner cartridge TC are inserted (FIG. 
6A) and reach the terminal end of the insertion stroke, the downward 
projection SS3 of the lower shutter member SS is engaed with the 
projection J1 of the copying apparatus main body 1 (FIG. 6B). This 
restrains the upper and lower shutter members US, SS from being relatively 
moved with respect to the copying apparatus main body 1. When the 
developing unit GU and the toner cartridge TC are further inserted, the 
compression coiled springs FU, FS are contracted, and the developing unit 
GU and the toner cartridge TC are relatively moved with respect to the 
shutter members US, SS. Accordingly, the apertures GU2, TC2 in the 
developing unit GU and the toner cartridge TC are opened. At the same 
time, the developing unit GU and the toner cartridge TC are stopped as 
coming in contact with the s topper L (FIG. 6C). When removing the 
developing unit GU and the toner cartridge TC, the operations 
above-mentioned may be reversed. That is, the developing unit GU and the 
toner cartridge TC may be removed with the apertures TC2, GU2 closed by 
the shutter members US, SS. 
In this embodiment, the upper and lower shutter members US, SS for the 
toner cartridge TC and the developing unit GU are so biased as to close 
the apertures TC2, GU2. Accordingly, even though the toner cartridge TC 
alone or the developing unit GU alone is removed, no toner falls through 
the aperture TC2 or GU2. 
Provision is made such that the shutter members US, SS for the toner 
cartridge TC and the developing unit GU are interlockingly operated. This 
not only simplifies the structure to lower the production cost, but also 
prevents toner from scattering due to an undesired difference in 
opening/closing timing between the shutter members US, SS. 
The upward projection SS2 and the groove US2 serving as engaging means for 
interlockingly operating the shutter members US, SS, are disposed between 
the bottom TC1 of the toner cartridge main body T1 and the top surface GU1 
of the developing unit main body G1 and between the pair of guide grooves 
GU4. It is now supposed that the upward projection SS2 crosses the guide 
grooves GU4. In such a case, it is required to provide a space in which 
the upward projection SS2 is relatively moved with respect to the guide 
grooves GU4. It is difficult to seal such a space. According to the third 
embodiment, however, it is easy to seal the space between the bottom TC1 
of the toner cartridge main body T1 and the top surface GU1 of the 
developing unit main body G1. 
Fourth Embodiment 
FIGS. 16A, 16B, 16C show a fourth embodiment of the present invention. The 
fourth embodiment differs from the third embodiment in FIGS. 6A, 6B, 6C in 
the following two points. 
(i) Provision is made such that the toner cartridge TC and the developing 
unit GU are integrally inserted and removed as connected to each other by 
a predetermined holding force (See FIG. 16A). 
(ii) The stopper L has a stepped structure such that the developing unit GU 
and the toner cartridge TC are adapted to be stopped at different 
insertion stroke stop positions. Accordingly, the lower shutter member SS 
opens the aperture GU2 (See FIG. 16B) before the upper shutter member US 
opens the aperture TC2 (See FIG. 16C). When removing the toner cartridge 
TC and the developing unit GU, the upper shutter member US closes the 
aperture TC2 before the lower shutter member SS closes the aperture GU2. 
This fourth embodiment not only produces effects similar to those produced 
by the embodiment shown in FIG. 6A, but also securely prevents toner from 
scattering in the space between the opposite surfaces of the toner 
cartridge and the developing unit. 
It is a matter of course that the present invention is not limited to the 
embodiments above-mentioned, but a variety of modifications may be made 
without departing from the scope of the present invention.