Ink Cartridge

This invention relates to an ink cartridge for a printer that uses a latching arrangement to fit the cartridge to the printer.

In a known arrangement, the printer is provided with a recess for receiving an ink cartridge. In use, the cartridge is pushed into the printer and is latched in place as a spring-loaded lever in the printer travels along a track in the cartridge, and comes to rest in a pocket. The track is an M-shaped track, so that, by pushing the cartridge again, the spring-loaded arm is pushed along a different part of the track thereby releasing the lever from its pocket and permitting the cartridge to be ejected from the printer by a spring-biased sealing arrangement which has enough force to eject the cartridge after the spring-loaded arm has left its pocket.

An aim of the invention is to provide an improved latching arrangement for the ink cartridge of a printer.

According to a first aspect, the present invention provides an ink cartridge for a printer, the ink cartridge having a housing, and a latching portion engageable with a spring-loaded lever of the printer for detachably fixing the ink cartridge within a receiving slot formed in the printer, the latching portion being constituted by a recess formed in one end of the housing, the recess being formed with a latch which is engageable with the lever to fix the ink cartridge within the recess, wherein the ink cartridge is provided with a release mechanism which is engageable with the lever to disengage the lever from the latch.

Ih a preferred embodiment, the latch has a lever-engageable portion adjacent to the mouth of the recess, and a shoulder behind which a projection provided on the lever is engageable. Li this case, the latching portion may further comprise a slot defined by portions of the latch and the recess, the slot being configured for slidably receiving the lever.

Advantageously, the lever-engageable portion is inclined to the direction in which the lever enters the recess.

In a preferred embodiment, the release mechanism is constituted by an elongate member housed in a channel formed in the housing, one end portion of the elongate member being formed with a device for disengaging the lever from the latch. Preferably, said device is an inclined end portion of the elongate member, said end portion being inclined with respect to the direction in which the lever enters the recess.

Advantageously, the release mechanism further comprises a manually-engageable actuator positioned at the other end portion of the elongate member, the manually-engageable actuator being accessible at that end portion of the housing remote from said one end.

Preferably, the release mechanism is spring-biased away from the position in which it engages the lever.

A known ink cartridge incorporates a bag of ink positioned in a sealed enclosure within the casing of the cartridge. A flexible film, which is heat-welded onto the top of the base of the cartridge constitutes the sealed enclosure around the bag. In use, the sealed enclosure outside the bag is pressurised with air supplied by the printer, thereby urging the ink out of the bag and towards the heads of the printer. The bag is heat- welded onto a neck made of plastics material, the neck holding a valve, a packing member and a seal. The neck is heat-welded to the base of the cartridge to effect an airtight seal to the cartridge. The cartridge is completed by a clip-on lid which is press-fitted into place on the base of the cartridge. When the cartridge is inserted into a printer, the seal is pierced by a spike positioned within the printer, so that ink can subsequently be forced out of the bag towards the print heads.

Another aim of the invention is to provide an ink cartridge which has an improved sealing arrangement within a printer.

According to a second aspect, the present invention provides an ink cartridge for a printer, the ink cartridge comprising a casing housing an ink supply container, and a septum assembly for directing ink from the container to a print head of the printer via an aperture provided in a wall of the casing, the septum assembly being provided with a septum seal for sealing engagement with the interior of said wall, the septum seal being made of a resilient material that is piercable by a piercing device provided within the printer, wherein the septum seal is provided with a secondary seal surrounding that portion thereof that, in use, is pierced by the piercing device, the secondary seal sealingly engaging that portion of the interior of said wall that surrounds the aperture.

Preferably, the septum assembly is constituted by a septum and the septum seal, the septum having a neck connectable to the container, a tube leading from the neck towards that portion of the septum seal surrounding the secondary seal.

Advantageously, the secondary seal is an O-ring. Conveniently, the septum seal further comprises a further seal for sealing the perimeter thereof against the interior of said wall. Preferably the further seal is constituted by an O-ring.

In a preferred embodiment, the septum seal further comprises an additional seal for sealing the perimeter thereof against a surface of the septum. Preferably, the additional seal is an O-ring.

The septum seal may be sealingly housed within a recess formed in an end plate of the septum.

Advantageously, the end plate is sized to fit within the casing of the cartridge in such a manner that the secondary seal is compressed against the interior of said wall. Conveniently, the casing of the cartridge is provided with upstanding support means for the septum assembly, the support means being positioned a predetermined distance from said wall, the predetermined distance being less than the thickness of the end plate, whereby the secondary seal is compressed against the interior of said wall when the end plate is positioned between said support means and the interior of said wall.

A conventional printer is provided with a plurality of ink cartridges each containing ink of a different colour, and the printer is provided with a respective receiving slot for each of the ink cartridges. In order to prevent a cartridge containing ink of a given colour from being positioned within a receiving slot intended for a cartridge containing ink of another colour, each of the cartridges is formed with a keying portion that mates with a complementary keying portion formed in the respective receiving slot. The keying portions of the cartridges are all different, thereby preventing cartridges from being fitted incorrectly into the wrong receiving slots in the printer.

A disadvantage of this conventional printer is that a separate mould needs to be manufactured for each colour cartridge; or, at the very least, a part of each mould is changeable. This is still a disadvantage, in that such a mould needs to be removed from the moulding machine, and disassembled and re-assembled in between the moulding of separate colour cartridges.

In addition, such ink cartridges are usually moulded using plastics material of the same neutral colour, so that the cartridges look identical unless their keying portions are studied carefully. Consequently, if colour cartridges are mixed up in the production process, it is possible to send out cartridges labelled for one colour whilst having a keying portion for an entirely different colour.

A further aim of the invention is, therefore, to provide ink cartridges containing ink of different colours, the cartridges being manufactured using a common mould, and being provided with means for easily identifying the colour of the ink.

According to a third aspect, the present invention provides an ink container for a printer, the ink cartridge comprising a casing and an ink container positioned within the casing, wherein the casing is made of the material having the same colour as the ink in the ink container.

Advantageously, the casing is made of a plastics material by a moulding process.

According to a fourth aspect, the present invention provides an ink cartridge for a printer, the ink cartridge comprising a casing, an ink container positioned within the casing, and an auxiliary member associated with the casing, the casing being made of a material having a neutral colour, and the auxiliary member having the same colour as the ink in the ink container.

Preferably the auxiliary member is a lever which is engageable with a latching arrangement provided within the cartridge, the latching arrangements being provided for releasably locking the ink cartridge within a receiving slot in the printer.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which: -

Figure 1 is a schematic representation of an ink cartridge constructed in accordance with the invention, the cartridge being shown in conjunction with a spring-loaded lever of an associated printer;

Figure 2 is a perspective view of the base of an ink cartridge of Figure 1 ;

Figure 3a is a perspective view of an assembled septum and septum seal assembly for use with the cartridge of Figure 2;

Figure 3b is a perspective view similar to that of Figure 3a but showing the assembly from a different angle;

Figure 4a is an exploded perspective view corresponding to Figure 3a;

Figure 4b is an exploded perspective view similar to Figure 3b; and

Figure 5 is a perspective view of the ink cartridge base of Figure 2 with the assembly of Figures 3a and 3b positioned therein;

Referring to the drawings, Figure 1 shows an ink cartridge 1 which is adapted to engage within a complementary receiving slot provided in an associated printer. The printer is provided with a spring-loaded lever 2 which is engageable with a recessed portion 3 provided in the leading end portion of the cartridge. The lever 2 is pivotally mounted, at 4, within the printer, and is biased by means of a spring (not shown) in the direction of the arrow 5. The lever 2 carries a round peg 6 on its underneath side.

The recessed portion 3 of the cartridge 1 is shaped to define a ramp 7 adjacent to the leading end portion of the cartridge. The ramp 7 forms part of a projection 8 provided within the recessed portion 3, the projection defining a slot 9 within the recessed portion, the slot having a width which complements that of the lever 2. A pocket 10 is formed at the rear end of the projection 9.

The longitudinal edge portion of the cartridge 1 which, in use, is aligned with the lever 2 is formed with a channel which houses an elongate sliding plate 11 made of plastics material. The plate 11 is slidable within the channel, and is provided with a manually-engageable end portion 11a which extends from the rear end portion of the cartridge 1. A ramp 10b is formed at the other end of the plate 11. The plate 11 is biased by means of a spring (not shown) towards the position shown in Figure 1, that is to say the position in which the ramp 1 Ib is retracted away from the pocket 10.

The cartridge 1 is installed into the printer by aligning its leading end portion with the receiving slot provided in the printer, and by pushing the cartridge and its trailing end portion as indicated by the arrows 12. The cartridge 1 slides into the receiving slot until it abuts a portion of the printer's mechanism (not shown), that exerts a pressing force on the leading end portion of the cartridge as indicated by the arrows 13. This mechanism carries a spring-loaded, rubber-faced nozzle (not shown) that engages with a hole (not shown) in leading end of the cartridge 1, to impart air pressure to the interior of the cartridge. The mechanism also carries a pointed ink-receiving nozzle (not shown), made of plastics material, that pierces a rubber septum (not shown in Figure 1), in the

leading end portion of the cartridge 1. The cartridge 1 can then provide a supply of ink to the ink-receiving nozzle.

During the process of pushing the cartridge 1 into the printer, the cartridge pushes the spring-biased mechanism further into the printer. At the same time, the spring-loaded lever 2 enters the recessed portion 3 of the cartridge. As the cartridge 1 is pushed into the receiving slot in the printer, the lever 2 is forced towards the slot 9, against the biasing force of the spring. When the cartridge 1 is fully pushed into the receiving slot, the peg 6 on the lever 2 is forced into the pocket 10 by means of the spring acting in the direction of the arrow 5. The cartridge 1 is then held firmly within the receiving slot of the printer, in opposition to the spring-biased mechanism acting in the direction of the arrows 13, while securely engaging the air-introducing means and the ink-receiving nozzle of the printer.

In order to release the cartridge 1 from the printer, the peg 6 of the lever 2 must be urged out of the pocket 10. This is accomplished by the user manipulating the elongate sliding plate 11. Thus, the user presses the manually-engageable end portion 11a, thereby forcing the sliding plate 11 along the channel formed in the longitudinal edge of the cartridge 1 until the ramp 1 Ib engages with the peg 6 to force it out of the pocket 10.

Once the peg 6 is free of the pocket 10, the spring-biased mechanism of the printer, acting in the direction of the arrows 13, ejects the cartridge 1 from the receiving slot in the printer, the peg 6 sliding freely along the slot 9 during this process.

Tn order to identify the colour of the ink contained in the cartridge 1, without the use of different keying portions for each ink colour, the cartridge is moulded using a plastics material having the same colour as the ink to be contained. Alternatively, the cartridge is moulded from a plastics material having a neutral colour, and the lever 11 is moulded using a plastics material having the same colour as the ink to be contained. In either case, there is no need for the cartridge 1 to be provided with a keying portion (which

keying portions would need to be different for cartridges containing inks of different colours), so that the same mould can be used for all cartridges.

Where a cartridge 1 is moulded from a plastics material having the same colour as the ink to be contained, its lever 11 can be moulded from a plastics material having a different colour to indicate its ejecting function. In addition, the lever 11 may be embossed with wording or a logo that further indicates its ejecting function. This notification on the ejection function may be further enhanced by a label fitted to the front wall of the cartridge 1.

Figure 2 shows the base 21 of the cartridge 1, the lid of the cartridge not being shown to illustrate the internal features of the cartridge. The base 21 defines an internal compartment 22 which, in use, receives an ink cartridge bag (not shown). This bag is of conventional design, and so will not be described.

That end of the cartridge 1 which first enters the receiving slot of the printer is provided with two apertures 23 and 24, the first of which is used to transfer ink from the cartridge to the printer, and the second of which is used for refilling the cartridge. A septum assembly support 25 is positioned within the base 21 adjacent to the apertures 23 and 24, the support having two upstanding shoulders 25a and 25b and two curved support surfaces 25c and 25d. The assembly 25 is positioned a small distance d from the interior wall of the cartridge base 21 which contains the apertures 23 and 24.

Figures 3 and 4 show a septum and septum seal assembly 26 which, in use, is positioned on the support 25 within the cartridge base 21. The assembly 26 is constituted by a septum 27 and a septum seal 28. The septum 27 includes a neck 29 and a septum plate 30, the mouth of the ink bag being heat-welded to the neck. The neck 29 is provided with apertures 29a and 29b through which ink passes respectively during transfer from the bag to the printer and for refilling. The apertures 29a and 29b are connected to the septum plate 30 by respective ink tubes 31 and 32.

The plate 30 is shaped to receive the septum seal 28, the septum seal being provided with an O-ring seal 33 which seals against the internal surface of the plate. The septum seal 28 is made of a resilient material such as rubber, and is provided with an ink supply tube 34 which mates with the tube 31 when the septum seal 28 is positioned within the plate 30.

The front face 35 of the septum seal 28 is provided with an O-ring seal 36 which extends around its periphery, and with an O-ring seal 37 co-axial with, but of a slightly larger diameter than, the ink supply tube 34.

In use, the septum seal 28 is fixed within the plate 30, and the ink bag is heat-welded to the neck 29 of the septum 27. The entire assembly is then fitted into the base 21 of the ink cartridge 1 with the plate 30 being a friction fit within the gap between the support assembly 25 and the interior wall of the cartridge base 21 that contains the apertures 23 and 24. This friction fit is such that the O-rings 36 and 37 are compressed against that interior wall to provide a good seal thereagainst. The arrangement is such that the tubes 31 and 32 are aligned with the apertures 23 and 24, and these tubes are supported by the curved support surfaces 25c and 25d. This arrangement is shown in Figure 5. The lid of the cartridge 1 is then ultra-sonically welded to the base 21 prior to the cartridge being inserted into the receiving slot of the printer.

As the cartridge 1 is fully inserted into the receiving slot, a spike within the printer pierces that portion of the septum seal 28 which is aligned with the ink supply tube 31 so that, when air pressure is imparted to the interior of the cartridge, ink contained in the bag is forced out through the tubes 31 and 32 towards an associated print head.

It will be appreciated that the O-ring seals 36 and 37 provide a good seal against the interior wall of the base 21 of the cartridge 1. The provision of the seals is particularly important as the front face 35 of the septum seal 28 is made of relatively thin rubber, and would, therefore, not provide a good sealing surface against the interior wall once that front face is pierced by the printer spike. It will be apparent, therefore, that the

septum and septum seal assembly 26 constitutes an improved sealing arrangement for an ink cartridge of this type.

It will be apparent that modifications could be made to the ink cartridge described above. For example, each of the O-rings 33, 36 and 37 could be constituted as a half O-ring, that is to say its cross section could be semi-circular rather than circular.