Ink cartridge for printer

A self-aligning ring for receipt within the ink supply port of an ink cartridge is provided. The ring includes, on the side thereof facing the interior of the ink cartridge, a first annular seal member whose inner diameter is slightly smaller than the outer diameter of an ink supply needle of a recording head, and on the side thereof facing the exterior of the ink cartridge, the ring includes a second annular seal member whose outer diameter is slightly larger than the inner diameter of the ink supply port. The seal members are connected by a thin flexible connecting member. If the ink supply needle is not positioned precisely coaxial with respect to the ink supply port, or even if the ink supply needle is not positioned precisely perpendicular to a recording head, the first annular seal member is displaced to conform with the ink supply needle position by deforming only the thin connecting member, and is hermetically fitted to the ink supply needle. Thus, ink is prevented from leaking from this seal. Where a multichannel ink cartridge for color printing is provided, a self-aligning ring would be mounted in the ink supply port of each compartment for cooperation with an associated ink supply needle.

BACKGROUND OF THE INVENTION 
The present invention relates generally to an ink cartridge for use with an 
ink-jet type recording apparatus and, more particularly, to an ink 
cartridge for use with an ink-jet type recording apparatus which 
compensates for misalignment of the ink supply port and ink supply needle 
to stop any ink from leaking. 
Ink-jet the recording apparatuses use liquid ink to print recording data. 
Particularly, an ink-jet type recording apparatus employs an ink cartridge 
that supplies ink contained therein to the recording head. The ink 
cartridge is directly connected to the recording head through the use of 
an ink supply needle mounted on the recording head. Ink is delivered by 
utilizing a pressure difference between the ink in the recording head and 
the ink in the ink cartridge, and by capillary forces. 
As a result of this construction, the ink cartridge is required to have a 
structure for connecting the ink cartridge to the ink supply needle. This 
structure is disposed either on the lower surface of the ink cartridge or 
below the ink cartridge itself. This arrangement of the connecting 
structure in turn requires that an appropriate measure be taken to contain 
leakage of ink from the ink cartridge when the cartridge is connected to 
the ink supply needle. As has already been disclosed in Japanese 
Unexamined Patent Publication No. 50-74341, one method of dealing with the 
leaking of ink which is widely used is to employ a package having a 
through-hole and a seal that allows the ink supply needle to be 
hermetically fitted into this through-hole at the ink supply port of the 
ink cartridge. With this structure, the ink cartridge can be positioned 
and retained in contact with the recording head without allowing any ink 
to leak by inserting the ink supply needle into the through-hole of the 
package so as to pierce the seal. 
In order to prevent any ink from leading, the ink supply port provided on 
the ink cartridge must have a minimal diameter. This design further 
requires a minimal diameter for the through-hole in the packing that is 
disposed in the ink supply port. However, if the ink supply needle is not 
positioned precisely coaxial with the through-hole in the packing disposed 
in the ink supply port, or if the ink supply needle is not perfectly 
perpendicular with respect to the packing disposed in the ink supply port, 
then the ink supply needle will not be centered upon insertion into the 
through-hole of the packing. As a result, the ink supply needle will be in 
contact with only a portion of the packing, whereas the remaining portion 
of the packing will not come in contact with the ink supply needle. Thus, 
ink will leak from between the ink supply needle and the packing where the 
ink supply needle does not contact the packing. 
This problem of leaking ink also arises from inconsistent positioning 
tolerances among the multiple ink supply needles in a recording head for a 
color printer using more than one ink supply needle to supply color inks 
to a recording head from a plurality of color ink tanks. In many cases, 
the plurality of color ink tanks is provided as a plurality of 
compartments in a single tank, so that the spacing between the connecting 
structures of the ink tank compartment and between the respective ink 
supply needles is fixed, aggravating the tolerance problem. 
Accordingly, the present invention provides an ink tank with a seal which 
compensates for inconsistent positioning of ink-supply needles, or 
inconsistent inclines of ink-supply needles and keeps ink from leaking 
from the ink supply tank while in use. 
SUMMARY OF THE INVENTION 
Generally speaking, in accordance with the present invention, a novel ink 
cartridge is provided which is capable of compensating for any 
displacement of the ink supply needle with respect to the ink supply port 
at the time the ink supply needle is connected to the ink supply port. The 
needle and port can be connected without allowing the ink to leak. 
The ink cartridge of the present invention comprises a self-aligning ring 
operatively coupled to the ink supply port of the ink cartridge on the 
outlet or recording head side. In operation, the ink supply port is 
coupled with an ink supply needle emanating from the recording head 
through the self aligning ring. The self-aligning ring includes: a first 
annular seal member whose inner diameter is slightly smaller than an outer 
diameter of the ink supply needle; a second annular seal member whose 
outer diameter is slightly larger than an inner diameter of the ink supply 
port; and a thin connecting member for connecting the two seal members. 
When coupled, even if the ink supply needle is not located precisely 
coaxial with the ink supply port, the ink supply needle can be connected 
to the ink supply port hermetically by flexing the thin connecting member, 
thereby eliminating any leaking of the ink. 
Accordingly, it is an object of this invention to provide an improved ink 
transfer mechanism for transferring between an ink cartridge and a 
recording head. 
Another object of the invention is to provide an improved ink transfer 
mechanism capable of compensating for any misalignment of the ink supply 
needle with respect to the ink supply port during use. 
A further object of the invention is to provide an improved ink transfer 
mechanism wherein a self-aligning ring permits a hermetic seal between an 
ink cartridge and a recording head regardless of misalignment of the ink 
supply needle with respect to the ink supply port during use. 
Still other objects and advantages of the invention will in part be obvious 
and will in part be apparent from the specification and drawings. 
The invention accordingly comprises the features of construction, 
combination of elements, and arrangement of parts, which will be 
exemplified in the construction hereinafter set forth, and the scope of 
the invention will be indicated in the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 show an ink cartridge constructed in accordance with a 
preferred embodiment of the present invention. The ink cartridge of this 
embodiment is designed for monochromatic printers. Referring to FIG. 2, an 
ink cartridge main body, indicated generally as 1, is integrally formed 
into a box having an opening on top. Ink cartridge main body 1 is made of 
a resin material that suppresses evaporation of ink and is constructed to 
allow air passage. 
The upper opening of ink cartridge main body 1 is covered integrally with a 
cover 2 having both an ink charging port 3 sealed by a spherical stopper 4 
and an air vent 5 similarly sealed by a spherical stopper 6 designed to 
permit air flow into the ink cartridge while preventing ink loss. The air 
vent 5 communicates with atmosphere through a winding groove 61 and an air 
communication hole 60. An ink supply port, indicated generally as 10, is 
formed on one side of the bottom of ink cartridge main body 1. Ink supply 
port 10 communicates with an ink supply needle 31 of a recording head (not 
shown). Further, an ink absorbing member 8, formed of a flexible porous 
material, is disposed within main body 1. A biasing plate 7 is positioned 
with respect to cover 2 to form a gap between cover 2 and ink absorbing 
member 8. The ink supply needle is positioned relative to the ink 
cartridge by a positioning member 33 which is dimensioned to receive an 
outwardly projecting portion 12 of the ink receiving and transmitting 
portion of the ink cartridge which defines the ink supply port. 
Reference is now made to FIG. 1, wherein ink supply port 10 is shown in 
enlarged form. Ink supply port 10 includes an inward projecting portion 11 
and an outward projecting portion 12. Inward projecting portion 11 
projects inward into ink cartridge main body 1 to bias ink absorbing 
member 8. Outward projecting portion 12 projects outward from ink 
cartridge main body 1 to position ink cartridge main body 1. Inward 
projecting portion 11 assists the flow of ink within ink absorbing member 
8 to ink supply port 10 by compressing ink absorbing member 8 in the area 
adjacent inward projecting portion 11 to produce an average pore diameter 
of ink absorbing member 8 at this location smaller than the average pore 
diameter of absorbing body 8 at locations not adjacent inward projecting 
portion 11. This reduction in the average pore diameter in the vicinity of 
inward projecting portion 11 increases the capillary force, assisting the 
ink flow to ink supply port 10. Mesh filter 34 is positioned at the end of 
inwardly projecting portion 11 to assist in preventing particles and air 
bubbles from entering the ink supply port. Outward projecting portion 12 
positions ink cartridge main body 1 by engaging a plurality of ribs 13 
arranged on the circumferential surface of ink cartridge main body 1 with 
an annular positioning projected edge 33 disposed on the back of the 
recording head and also aids in connecting ink supply port 10 to ink 
supply needle 31. 
A stepped insertion hole 14 in outward projecting portion 12 is dimensioned 
to receive a self-aligning ring 20 (described below). In addition, a 
through-hole 16 serving as an ink through-hole (part of the ink supply 
port) is provided in inward projecting portion 11. Stepped insertion hole 
14 and through-hole 16 are formed coaxially so as to communicate with each 
other when ink cartridge main body 1 is coupled with in supply needle 31 
of the recording head. 
Self-aligning ring 20 will now be described with reference to FIG. 1. 
Self-aligning ring 20 is made of a flexible resin material and comprises 
three distinct portions. A ring-like annular needle seal 21 (the first 
seal) having a circular form in section is coupled with a ring-like 
annular port seal 22 (the second seal) having a circular form in section 
by a thin truncated conical connecting ring 23 that is thinner than 
annular needle seal 21 or annular port seal 22 in the axial direction. The 
inner diameter of annular needle seal 21 is slightly smaller than the 
outer diameter of ink supply needle 31. The outer diameter of annular port 
seal 22 is slightly larger than the inner diameter of an entrance portion 
14a of stepped insertion hole 14. 
A ring-like movable bush 24 having an L-shaped form in cross section is 
fitted adjacent annular needle seal 21 from outside so as to suppress the 
expansion of needle seal 21. The inner diameter of movable bush 24 is 
substantially smaller than the inner diameter of a portion 14b of stepped 
insertion hole 14. In addition, a ring-like fixed bush 25 having an 
L-shaped form in section is positioned within annular port seal 22 so as 
to insure fixed bush 25 remains in contact with the inner surface of 
entrance portion 14a of stepped insertion hole 14. Fixed bush 25 is 
dimensioned so that the inner end of fixed bush 25 does not come in 
contact with needle seal 21. Fixed bush 25 guides ink supply needle 31 
into stepped insertion hole 14 during insertion. Fixed bush 25 is mounted 
in such a manner that movable bush 24 is in sliding contact with stepped 
portion 15 within stepped insertion hole 14 and that fixed bush 25 is 
fitted into entrance portion 14a of insertion hole 14. 
Radially extending projected bars 24a are formed on the inner end surface 9 
movable bush 24 and are maintained in sliding contact with stepped portion 
15 within stepped insertion hole 14. When ink is injected into ink 
cartridge main body 1, ink cartridge main body 1 is evacuated to a 
negative pressure. A plurality of through-holes 24b are formed between 
projected bars 24a of movable bush 24 so that essentially all of the air 
within stepped insertion hole 14 can be released from around self-aligning 
ring 20 through through-holes 24b between the projected bars 24a. 
Additional through holes 25a are formed in fixed bush 25 for the same 
purpose. The releasing of the air in this manner prevents the ink charging 
pressure from causing self-aligning ring 20 from being detached from 
insertion hole 14. In effect, during injection of the ink into ink 
cartridge body 1 under negative pressure, ink essentially occupies the 
portion of insertion hole 14 not occupied by self-aligning ring 20, 
movable bush 24, and fixed bush 25. 
First seal member 9 in FIG. 2 seals the opening end of ink charging port 3, 
and second seal member 17 in FIG. 1 seals the opening end of ink supply 
port 10, and is penetrated by ink supply needle 31 during mounting of the 
ink supply cartridge. 
An electrode 35 extends through a bore 36 in a wall of ink cartridge body 1 
and serves as one electrode of an ink exhaustion sensor to inform the user 
that the ink cartridge requires replacement. An O-ring 37 prevents escape 
of ink through bore 36. 
The procedure for attaching ink cartridge main body 1 to a recording head 
will now be described. Ink cartridge main body 1 is coupled with the 
recording head in such a manner so as to align ink supply port 10 with ink 
supply needle 31. Ink supply needle 31 is inserted into ink supply port 10 
while piercing seal member 17 that seals ink supply port 10. Ink supply 
needle 31 then enters into through-hole 16 and is hermetically fitted with 
movable bush 24. Simultaneously therewith, ribs 13 disposed around the 
circumference of the outward projecting portion 12 are fitted into annular 
positioning projected edge 33a of positioning member 33 disposed on the 
recording head to thereby fix ink cartridge main body 1 in position. Ink 
cartridge main body 1 is attached to the recording head so as to align ink 
supply needle 31 with positioning projected edge 33 even if ink supply 
needle 31 is not projected precisely coaxial with through-hole 16, or if 
ink supply needle 31 does not project precisely perpendicularly from the 
recording head. As shown in FIG. 3, ink supply needle 31 is hermetically 
fitted to needle seal 21 even if not properly situated without greatly 
deforming needle seal 21. Needle seal 21 moves with movable bush 24 along 
stepped portion 15 within insertion hole 14 upon insertion of tapered tip 
portion 32 of ink supply needle 31, and thin conical connecting ring 23 is 
deformed and displaced in the radial direction outward. Thus, ink supply 
needle 31 is correctly fitted regardless of the precise position or angle 
of ink supply needle 31. Reference is now made to FIG. 3 which depicts the 
positioning of the movable bush 24 and self-aligning ring 20 when an ink 
supply needle 31 is not aligned with the axis of insertion hole 14. 
Reference is now made to FIGS. 4 and 5 wherein a second embodiment of the 
present invention is shown, like elements being given like reference 
numerals. This second embodiment depicts a mechanism for use with color or 
other multi-ink printers. A cartridge main body 41 has a plurality of ink 
tanks or compartments 42a, 42b, 42c fixed integrally thereto for 
containing different color inks. Ink supply ports 50a, 50b, 50c having 
similar self-aligning rings 20a, 20b, 20c are disposed on the bottoms of 
ink tanks 42a, 42b, 42c. Each ink tank 42a, 42b and 42c has an air vent 
sealed by a stopper 6a, 6b and 6c respectively (FIG. 4). The ink charging 
ports of the three ink tanks or compartments are covered and sealed by 
sheet member 9'. 
In the situation where ink cartridge 41 is attached to a recording head 
having inconsistent positioning tolerances among ink supply needles 31a, 
31b, 31c (FIG. 5), self-aligning rings 20a, 20b, 20c inside the ink supply 
ports 50a, 50b, 50c are designed so that the misaligned ink supply needles 
displace the respective needle seals 21 and movable bushes 24 as described 
above so as to align each needle seal 21 with the position of the 
corresponding ink supply needle 31a, 31b, 31c while flexing each 
corresponding thin conical connecting ring 23. This construction thereby 
prevents the ink from leaking, and permits fitting and retaining each ink 
supply needle 31a, 31b, 31c hermetically with the corresponding needle 
seal 21 by only deforming the thin connecting members 23. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in carrying out the above method without 
departing from the spirit and scope of the invention, it is intended that 
all matter contained in the above description shall be interpreted as 
illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.