HK1072916B - Ink-jet pen with two-part lid and techniques for filing - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates to ink-jet printing, and more particularly to filling techniques for ink-jet pens and to case structures for such pens.

BACKGROUND OF THE INVENTION

Ink-jet printers are in widespread use today for printing functions in personal computers, graphics plotters, facsimile machines and other applications. Such printers typically include replaceable or semipermanent print cartridges which hold a supply of ink and carry the ink-jet printhead. The cartridge typically is secured into a printer carriage which supports one or a plurality of cartridges above the print medium, and traverses the medium in a direction transverse to the direction of medium travel through the printer. Electrical connections are made to the printhead by flexible wiring circuits attached to the outside of the cartridge. The carriage receptacle has a corresponding electrical circuit with exposed contact pads which contact cartridge interconnect pads when the cartridge is mounted in the carriage. Each printhead includes a number of tiny nozzles defined in a substrate and nozzle plate structure which are selectively fired by electrical signals applied to the interconnect pads to eject droplets of ink in a controlled fashion onto the print medium. The cartridge may be connectable to auxiliary supplies of ink for replenishing the internal supply held in the cartridge.

In order to achieve accurate printing quality, each removable cartridge includes datum surfaces which engage against corresponding carriage surfaces to precisely locate the cartridge when inserted into the carriage. In this manner, when a cartridge ink supply is exhausted, the cartridge may be replaced with a fresh cartridge, and the printhead of the new cartridge will be precisely located relative to the carriage. The printer carriage receptacle and the cartridge are therefore designed together, so that the cartridge fits accurately within the carriage receptacle, the respective circuit pads and datum surfaces match up, and the cartridge can be removed and replaced with a fresh cartridge as needed.

US 5,777,647 discloses a free-ink ink-jet pen including a regulator module having a two-part lid structure. A lid portion is permanently affixed to a housing of the module and includes a labyrinth vent channel. A cover portion overlays the vent channel and includes a vent hole.

GB 2 310 168 discloses an inkjet cartridge having a housing with an open region, a printhead mounted on the housing, at least one internal fluid reservoir, a foam structure within the reservoir, and a two-part lid structure. The lid structure includes a lid portion permanently attached to the housing and a cover portion that is movable between an open position enabling the reservoir to be filled and a closed position.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, there is provided an inkjet cartridge as set forth in the accompanying claim 1.

Further aspects are set out in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWING

These and other features and advantages of the present invention will become more apparent from the following detailed description of an exemplary embodiment thereof, as illustrated in the accompanying drawings, in which:

• FIG. 1 is an isometric view of a small form factor inkjet cartridge with which the subject invention can be employed.
• FIG. 2 is a bottom view of the cartridge of FIG. 1.
• FIG. 3 is a simplified side view illustrating the latching of the cartridge of FIG. 1 in a carriage receptacle.
• FIG. 4 is an isometric view of the cartridge of FIG. 1 mounted in a carriage receptacle.
• FIG. 5A is a schematic diagram illustrating exemplary components of a refill kit useful in a technique for refilling an inkjet cartridge. FIG. 5B is a schematic illustration of the cartridge with elements of the refill kit during a refill procedure.
• FIG. 6 is a bottom isometric view of a one-piece lid structure.
• FIG. 7 is a top view of the lid structure of FIG. 6 with a template in place to identify locations of fill ports.
• FIG. 8 illustrates an exemplary embodiment of a two-part lid structure in accordance with an aspect of the invention.
• FIG. 9 is an isometric view of the lid structure of FIG. 8, showing the cover in an open position to expose the fill ports formed in the lid.
• FIG. 10 shows an alternate arrangement of the two-part lid structure, which allows the cover to be lifted up and detached from the lid for refill.
• FIG. 11 is an isometric view illustrating a further alternative embodiment of the two-part lid structure, wherein the cover is attached to the lid structure with a hinge on the back of the lid structure.
• FIG. 12 is an isometric view illustrating an alternative embodiment of the hinged two-part lid structure, wherein the hinge is located along a longitudinal edge of the cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

There is disclosed herein a refill technique for a low profile inkjet print cartridge. One exemplary low profile cartridge is described in US 6,332,676 , although other cartridges can alternatively be employed in practicing the invention. The following description of the exemplary cartridge is generally taken from the above reference application.

A small form factor inkjet cartridge 20 is shown in FIGS. 1-4, and is characterized by a relatively small height dimension H1, in this exemplary embodiment on the order of 45 mm. This is compared to a typical height dimension of 72 mm for the HP 51629A (black ink), 51629G (black ink), 51649A (tri-color) and 51649G (tri-color) cartridges marketed by Hewlett-Packard Company. The width dimension W1 and depth dimension D1 are the same as for these already marketed cartridges; typical values for W1 and D1 are 30.9 mm and 48.3 mm, respectively. The small form factor cartridge 20 has utility for a variety of applications, including by way of example low profile printing devices and entertainment center printers.

The cartridge 20 includes a cartridge housing 22, typically fabricated of a plastic material, to which a top end cap or lid 24 is attached, e.g. by adhesive or ultrasonic bonding techniques. A bottom end cap or nose piece 26 is attached to the lower end of the housing, and supports a printhead 28 (FIG. 2). The housing 22 has formed therein at least one ink reservoir chamber, filled with a foam material in this example, for holding a supply of ink to supply the printhead during printing operations for delivering ink droplets onto a print medium during printing operations. The ink compartments in this exemplary embodiment receive foam structures (not shown in FIG. 1) which hold the ink in open foam cells, and create slight negative pressure through capillary action, as is well known in the art. The ink reservoir includes an ink outlet port in fluid communication with each chamber.

The printhead is fabricated in this exemplary embodiment as part of a TAB flexible circuit attached to the housing, and the bottom end cap, and includes a plurality of ink ejection orifices generally indicated as 28A (FIG. 2) communicating with the supply of ink in the reservoir through a reservoir outlet port. The TAB circuit further includes a cartridge set of electrical contact pads, which are interconnected through the TAB circuit to corresponding nozzle firing resistors of the thermal inkjet printhead. When the cartridge is mounted in a carriage receptacle, the cartridge set of contacts is brought into contact with a corresponding set of carriage contacts, for supplying drive signals to the printhead. Other types of cartridge reservoirs, printheads, and circuits can alternatively be employed without departing from the invention.

The top cap or lid 24 of the cartridge body has formed as an integral part thereof a boss or beveled latch feature 24A, and a keying feature 24B. The latch feature 24A is adapted to provide a latching surface against which a carriage latch member engages as the cartridge is inserted into a carriage receptacle adapted to receive the cartridge. This is illustrated in FIG. 3, wherein a cantilevered latch spring 104 is shown in a latched position relative to the cartridge body. The keying feature 24B is adapted to match with corresponding receptacle keying features, when the cartridge is mounted in the carriage receptacle.

FIG. 4 illustrates the cartridge 20 mounted in a carriage 100, and particularly in a carriage receptacle 102 which is dimensioned particularly to receive the cartridge 20. The cartridge and the receptacle are particularly adapted for use as a front loading system, wherein the cartridge is inserted in a sideways-facing receptacle opening or guide chute. The guide chute can be formed as an injection molded part, with short sidewall structures on the bottom and left and right sides of the chute. A carriage latch feature 104 and a receptacle keying feature 106 are formed at the top side of the receptacle chute. Thus, the guide chute is formed on three sides by short walls which extend only along a short portion of the cartridge body. To load the cartridge 20 into the receptacle carriage receptacle, the bottom of the cartridge is first inserted into the guide chute at an angle, and then the back of the cartridge is pushed back to engage the latch spring over the latch feature of the cartridge.

A refill kit 150 is described which provides an apparatus to fill or refill a multi-compartment inkjet cartridge such as the cartridge 20. In one example, the main components of the refill system 150 are a refill station including a fixture 190, an ink supply 160 which includes fill needles, a capping system 180 to provide a seal around the cartridge nozzle arrays to evacuate air and prime the cartridge when it is refilled, a vacuum source 192 to connect to the capping system, and the tool(s) 194, 196 to make the necessary refill ports in the top lid of the cartridge, for the cartridge type employing a non-removable lid. As will be described more fully below, an alternate example employs a removable lid or cover on the cartridge to expose the fill ports.

FIG. 5B illustrates a technique using a refill ink container 160 comprising the refill kit. The refill container 160 in this example includes an integrated housing structure, wherein the exterior walls and interior walls 160A, 160B define a plurality of ink chambers 162, 164, 166.

The housing 160 has a bottom surface 168, which includes keying features which mate with the features 24B formed on the top lid 24 of the cartridge 20, and a recess to clear the push feature 24F formed on the top lid. In the example of FIG. 5B, the bottom surface 168 has formed therein keying feature 170 at the bottom of the first chamber 162, to ensure that the correct refill kit is used with the particular cartridge 20. The bottom surface 168 further has formed therein the recess 172 at the bottom of the third chamber 166 to clear the push feature 24F protruding from the surface of the lid.

In this example, the chambers 162, 164, 166 are sized to provide equal volumes for holding liquid ink to refill the corresponding ink chambers 40, 42, 44 of the inkjet cartridge 20, regardless of the volume taken up for the key feature 172 and the recess feature 172.

A plurality of hollow fill needles protrude downwardly from the bottom surface 168 of the ink container 160. The fill needles are each in fluid communication with a corresponding ink chamber of the container 160. The needles are designed to penetrate the foam within the chambers 40, 42, 44 of the cartridge 20 to a predetermined depth to ensure good ink fill.

It will be appreciated that some cartridges will have a single chamber, e.g. a black ink cartridge. In this case, the refill container 160 corresponding to this cartridge can be constructed as well with a single large chamber, preferably with three fill needles, although the number of needles can be varied according to the requirements of a particular application. Alternatively, a three chamber refill supply as shown in FIG. 5B can be employed, with all three chambers holding the same type and color of ink, so that a single large compartment in the cartridge 20 is refilled by ink from a plurality of chambers in the refill supply.

In this example, the refill station includes a housing or fixture 190 to fixture the pen, and an apparatus including capping system 180 and vacuum source 192 to apply vacuum to the nozzle plate. The fixture 190 can be a stand-alone fixture, which can include bracketry to hold the ink container 160 and the cartridge 20 during the refill procedure. In an alternate example, the capping station in the printer is adapted to serve as the refill station. This is generally shown in FIG. 5B. In this case, an "Out of Ink (OOI)" message generated by the printer controller can be used to trigger the start of the refill cycle, either automatically or to prompt the user to refill the cartridge. The OOI message along with the correct carriage position can be stored in the printer registers and transferred to the refill station, which may be part of the printer or a separate unit. In another example, the fixture or filling station can be built into the printer housing structure, similar to the humidor/garage supplied with single pen printers, e.g. the Hewlett Packard DeskJet 500C printer, to store the unused cartridge.

The vacuum required to perform the ink fill may be applied by a manual prime pump, a small vacuum pump or by fittings to attach to a house vacuum cleaner. The vacuum may not be required to fill an already wet foam but can be used to evacuate the pen so as to start the fill process at a known empty point. This can be especially useful when filling a tri-chamber pen, where the overall weight of the pen does not necessarily indicate the residual ink in each of the three chambers.

Another optional component of the refill station is an ink level monitor to determine whether refill is needed (when the refilling is done manually) or when to stop filling ink. The "full" message will be sent to the ink supply either electronically or mechanically to ensure that an already full pen is not refilled thereby causing an ink spill. The ink fill level sensing system can include ink level sensors 182A, 182B, 182C (FIG. 5B) which indicate the ink level in the respective chambers 40, 42, 44 of the cartridge during the fill procedure.

The ink supply 160 may be a single or multi-chamber structure, depending on the cartridge it is designed to refill. The ink supply also preferably has hollow fill needles (or other suitable device) to penetrate the foam. There will also be a method to shut off the fill when the optimum level is reached. Another approach is to combine the needle and a sensor to sense ink level using electrical impedance or capacitance.

The capacity of the ink supply 160 can be selected in dependence on the capacity of the ink cartridge reservoir(s), and the refill operation conducted on an empty or almost empty ink cartridge. In this embodiment, the refill proceeds until all available ink in the ink supply 160 has been dispensed into the ink cartridge. The needles can be capped until ready for use. A closable vent can be proved in a top surface of the ink supply 160, and opened after the needles have been inserted into the fill port of the cartridge. Application of vacuum on the nozzle array of the cartridge then facilitates refilling the cartridge.

In another embodiment, the ink supply needles can be provided with a normally needle valve arrangement, such as the needle valve structure 120 described in U.S. 5,929,883 , and illustrated in FIGS. 4-6. In this embodiment, the needle valve is opened when the ink supply 160 and the cartridge are brought together and the needle inserted into the cartridge through its fill port. The valve structure can include a collar biased by a spring to a normally closed position, but when the needle is passed into the fill port, the collar is forced up the needle to expose needle openings, allowing ink to flow.

Other techniques for controlling the flow of ink from the ink supply to the ink cartridge can also be employed.

The ink supply 160 is also be designed in such a way that the first chamber 162 has keying features 170 to ensure that the correct ink supply is used for a given pen which is unique, as described more fully in US 6,290,346 . In addition the third chamber has a recess or cut out 172 to clear the push feature 24F of the cartridge 20. The individual chamber geometry will be chosen in such a way that each chamber contains the required amount of ink regardless of the volume taken up to implement the keys and to clear the push feature.

The top lid 24 of the cartridge 20 may or may not have exposed fill ports on all chambers to enable filling. In one example, which is outside the scope of the claims, the lid 24 does not include exposed fill ports. In this case, the cartridge is filled with ink at the factory before the lid is mounted to the housing. This lid 20 has several structures 24D protruding from the undersurface 24E of the lid, as illustrated in FIG. 6. These structures 24D serve as push features to apply compression force on the foam which is fitted into the ink chambers of the cartridge 20. To allow the cartridge to be refilled with ink, one or more fill ports are formed through the lid 24, e.g. by punching or drilling. The holes are preferably formed in appropriate locations in the lid to avoid the structures 24D. A tool can be provided to enable location of the fill port in the optimum location for each chamber. One simple technique is to provide a paper template for the user to place over the lid 24. The key/latch feature 24B and the thumb grip 24F can locate the template on the lid. The template has port indicia 302A-302C which indicate the locations of the fill ports to be formed in the lid, and which match the optimum locations L1-L3 (FIG. 6) which avoid the structures 24D. If the holes are punched, the punch tool can be included in the refill kit. Alternatively, for drilling the fill port holes, a drill bit size can be specified for the customer to purchase separately from a local hardware store.

After filling, the fill port holes can be left exposed, and the cartridge back pressure will tend to prevent ink stored in the foam from leaking. Alternatively, the fill port holes can be sealed with plugs or with tape, such as adhesive tape.

According to the invention, the inkjet cartridge 20 is provided with a two-part lid to facilitate easy refill by users, improved manufacturing flow, improved water loss performance for entertainment center environments, and minimize/eliminate ink leaks through a vent hole.

The two-part lid includes one part permanently affixed to the cartridge housing, the lid and a second part, the cover, which has the push feature (24F) for insertion and removal of the cartridge. The cover can be removed easily by the user, either with a simple tool such as a screwdriver or no tools at all, depending on the particular implementation. For example, depending on the embodiment, the cover can be opened by sliding off of the back of the lid, by tilting the cover to either of the lid sides, or to the front or the back of the lid, or by removing the cover vertically from the permanently attached lid. Opening the cover exposes the fill ports for the three chambers, which can then be filled by use of the refill kit described above.

FIG. 8 illustrates an exemplary embodiment of the two-part lid structure 24', which includes the lid 240 which is adapted to be permanently affixed to the cartridge housing by ultrasonic welding, adhesive or other known attachment techniques. The lid structure 24' further includes a cover member 242, which can be moved from a closed position to expose fill ports formed in the lid useful for filling and refilling the cartridge. The push feature 24F is incorporated in the cover structure 242.

The lid structure further includes a labyrinth vent 244, illustrated in further detail in FIG. 9, an isometric view of the lid structure 24', showing the cover 242 in an open position. Here, the cover is slid out to a refill position to expose the fill ports 240A-240C formed in the lid 240. The labyrinth vent 244 is also exposed with the cover in the refill position. The vent includes a labyrinth groove 244A formed in the top surface of the lid 240, running from the vent openings 244B, 244C, 244D formed through the lid structure for each ink chamber to a terminal at 244E, which is exposed when the cover is in the closed position (FIG. 8).

The cover 242 and lid structure 240 illustrated in FIGS. 8 and 9 can be formed in a with a tongue-and-groove dovetail arrangement to prevent the cover from upward movement relative to the lid plane, while permitting lateral sliding movement of the cover relative to the lid 240.

FIG. 10 shows an alternate arrangement 24" of the lid 240' and cover 242', which allows the cover to be lifted up and detached from the lid 240' for refill. The cover 242' can snap fit onto the lid 240', or a clasp can be provided.

FIG. 11 is an isometric view illustrating a further alternative embodiment 24''' of the two-part lid structure, wherein the cover 242" is attached to the lid 240" with a live hinge 246 on the back of the lid structure.

FIG. 12 is an isometric view illustrating an alternative embodiment of the hinged two-part lid structure 24", wherein the hinge 246' is located along a longitudinal edge of the cover 242"', instead of along a lateral edge as with the embodiment of FIG. 11.

The two-part lid 24 includes an improved vent to allow air to enter the ink chambers as ink is used, while minimizing vapor loss through the vent. With the cover portion in place, the vent path provided by the labyrinth groove 244A substantially reduces vapor loss. This enhances the performance of the print cartridge in hot and dry environments, e.g. an entertainment center environment. It is noted that labyrinth vents have been employed in the past, for example, in the Hewlett Packard model 51629 print cartridge. In that cartridge, however, the vent is not provided in a lid but in structure adjacent the nozzle array.

In addition to the improved water loss performance, the new vent design also helps in minimizing if not eliminate ink leaks through exposed vent holes.

The cartridge 20 is illustrated in FIG. 1 as having a one-piece lid, permanently attached to the cartridge housing structure after ink fill by ultrasonic welding or other attachment technique. For high volume manufacturing, the cartridge is preferably built from start to finish in one run or at least from foam insertion to the end of line. The two-part lid will help in completing the dry loop processes and having inventory available to complete the assembly as demand arises without compromising the shelf life of the cartridge which takes effect when ink is filled.

It is understood that the above-described examples and embodiments are merely illustrative of the possible specific embodiments which may represent principles of the present invention. Other arrangements may readily be devised in accordance with these principles by those skilled in the art without departing from the scope of the invention as defined by the accompanying claims.

Claims (3)

1. An inkjet cartridge (20), comprising:

   a cartridge housing (22) having an open region;

   a printhead (28) mounted on the housing;

   a plurality of datum surfaces (24A, 24B) on said housing for registering a position of the cartridge housing (22) in a fixed, repeatable position in a carriage structure (100);

   a cartridge set of electrical contacts mounted to the cartridge housing (22) and electrically coupled to the printhead (28), said cartridge set of electrical contacts positioned on the housing (22) for electrical contact with a corresponding first carriage set of electrical contacts when the cartridge (20) is mounted in the carriage structure (100);

   at least one internal ink reservoir (40; 42; 44) defined within the housing (22) in fluid communication with the printhead (28);

   a foam structure disposed within the at least one internal ink reservoir (40; 42; 44); and

   a two-part lid structure (24'; 24"; 24"') for covering the open region of the housing (22), the lid structure including:

   a lid portion (240; 240'; 240"; 240"') permanently attached to the housing (22) and including at least one fill port (240A-240C) in fluid communication with the at least one reservoir (40; 42; 44), the lid portion (240; 240'; 240"; 240"') further including a labyrinth vent including one or more vent openings (244B-244D) formed therethrough and a labyrinth vent groove (244A) communicating with the one or more vent openings, and

   a cover portion (242; 242'; 242"; 242"') that is movable between a closed position covering the at least one fill port (240A-240C) in the lid portion (240; 240'; 240"; 240"') and an open position in which the at least one fill port is exposed to enable the at least one reservoir (40; 42; 44) to be filled through said at least one fill port (240A-240C);

   whereby the one or more vent openings (244B-244D) are covered by the cover portion (242; 242'; 242"; 242"') when in the closed position and whereby the vent groove (244A) has a terminal portion which is not covered by the cover portion in the closed position.
2. A cartridge according to Claim 1, wherein the cover portion (242"; 242"') is hingedly attached to the lid portion (240"; 240"').
3. A cartridge according to Claim 1, wherein the cover portion (242) is slidingly engaged with the lid portion (240) to slide from the closed position to the open position.