Patent Grant
7862162
The present invention relates to fluidic couplings and in particular, ink couplings within inkjet printers.
The following applications have been filed by the Applicant simultaneously with the present application:
The disclosures of these co-pending applications are incorporated herein by reference.
The following patents or patent applications filed by the applicant or assignee of the present invention are hereby incorporated by cross-reference.
The Applicant has developed a wide range of printers that employ pagewidth printheads instead of traditional reciprocating printhead designs. Pagewidth designs increase print speeds as the printhead does not traverse back and forth across the page to deposit a line of an image. The pagewidth printhead simply deposits the ink on the media as it moves past at high speeds. Such printheads have made it possible to perform full colour 1600 dpi printing at speeds in the vicinity of 60 pages per minute, speeds previously unattainable with conventional inkjet printers.
The high print speeds require a large ink supply flow rate. Not only are the flow rates higher but distributing the ink along the entire length of a pagewidth printhead is more complex than feeding ink to a relatively small reciprocating printhead.
Some of the Applicant's printers provide the printhead as a user removable cartridge. This recognizes that individual ink ejection nozzles may fail over time and eventually there are enough dead nozzles to cause artifacts in the printed image. Allowing the user to replace the printhead maintains the print quality without requiring the entire printer to be replaced. It also permits the user to substitute a different printhead for different print jobs. A draft quality printhead can be installed for some low resolution documents printed at high speed, and subsequently removed and replaced with the original high resolution printhead.
A number of the Applicant's printhead cartridges do not have an inbuilt ink supply for the printhead. These printhead cartridges need to be fluidically coupled to the ink supply upon installation. The supply flowrate to the pagewidth printhead is too high for needle valves because of the narrow internal diameter. This requires the coupling conduits to be relatively large and therefore the engagement force required during installation is relatively high. The fluid seal is provided by a resilient element that is deformed during engagement. With larger conduits, the resilient element is larger and so to is the force required to deform it. Furthermore, full color printheads will have 3, 4 or even 5 separate couplings (CMY, CMYK, CMYKK or CMYK,IR) which only multiplies the additional coupling force necessary. Modern market expectations are that the installation and removal of cartridges and other consumables are simple and physically easy. It is also structurally undesirable to subject the cartridge to large forces. Flexing or bowing of the cartridge body can stress the electronics or nozzle structures.
Accordingly, the present invention provides a fluid coupling comprising:
a first conduit;
a second conduit having a seal seat and a compression member, the compression member being movable relative to the seal seat;
an annular seal positioned in the seal seat; and,
an engagement mechanism for moving the second conduit from a disengaged position where there is no sealed fluid connection between the first and second conduits, and an engaged position where the compression member moves toward the seal seat to compress the annular seal to form a sealed fluid connection.
The invention uses an engagement mechanism to deform the annular seal instead of the force of one conduit being pushed into the other. The exertion needed to establish the sealed fluid coupling can be reduced or removed by incorporating mechanical advantage or power assistance into the engagement mechanism. Also there is no force acting on the first conduit so it is not subjected to structural stresses.
Preferably, the engagement mechanism moves the second conduit such that it telescopically engages the first conduit and the second conduit prior to compressing the annular seal. Preferably, the engagement mechanism is manually actuated and compresses the seal with the assistance of a lever system. Preferably, the first conduit is part of a cartridge and the second conduit is part of a device that uses the cartridge during operation, the lever system latches to the cartridge when it has moved the second conduit to the engaged position. Optionally, the first conduit slides within the second conduit during telescopic engagement. Preferably, the annular seal is a ring of resilient material. In a particularly preferred form, the ring of resilient material has a radial cross sectional shape with at least one straight side when uncompressed, and said at least one straight side bulging to a curved shape when compressed.
In some embodiments, the lever system completely disengages the second conduit from the first conduit when it moves the second conduit to the disengaged position. Preferably, the cartridge has a plurality of first conduits and the device has a corresponding plurality of second conduits, and the lever system actuates to simultaneously engage and disengage the plurality of first and second conduits. In a further preferred form, the coupling has a corresponding plurality of the annular seals for each of the second conduits respectively, wherein the compression member is arranged to compress all the annular seals respectively, the second conduits formed in an arrangement with a geometric centroid at which the lever system connects to the compression member. In a particularly preferred form, the second conduits are arranged in a circle and the lever system connects to the centre of the circle.
In some embodiments, the device is a print engine for an inkjet printer and the cartridge has an inkjet printhead. In these embodiments, it is preferable if the inkjet printhead is a pagewidth inkjet printhead such that the cartridge has an elongate configuration and the lever system has a hingedly mounted latch for releasably engaging the cartridge to secure it in the print engine when in the engaged position and allow the cartridge to be lifted from the print engine when in the disengaged position. Preferably, half of the plurality of first conduits extend from an inlet manifold at one end of the elongate cartridge, and half of the plurality of first conduits extend from an outlet manifold at the other end of the elongate cartridge.
In particular embodiments, the first conduits extend transversely to the longitudinal extent of the elongate cartridge such that the plurality of second conduits move transverse to the longitudinal extent of the elongate cartridge when moving between the engaged and disengaged positions.
Preferably, the second conduit has a shut off valve that opens when the first and second conduits are in the engaged position and closes when they are in the disengaged position.
In some preferred embodiments, the lever system has an input arm hinged to the compression member, the input arm having a compression lever fixed at an angle to the longitudinal extent of the input arm, the input arm arranged to push against the compression member as it rotates about the hinge connection to the compression member, the compression member in turn pushes against the second conduit to move it relative to the first conduit, until the input arm reaches a predetermined angle about the hinge where the compression lever engages the second conduit such that further rotation of the input arm moves the compression member relative to the second conduit to compress the annular seal.
In further preferred forms, the device has a chassis and the lever system latches the cartridge with a latch arm hinged to the chassis, the latch arm being fixed for rotation with an actuation arm hinged to the input arm, such that user actuation of the latch arm advances and retracts the second conduit and the compression member. Conveniently, the latch arm provides the longest lever arm of the lever system and so requires the least force to rotate.
Preferred embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:
The invention will be described with specific reference to a fluid coupling between an inkjet print engine and its corresponding printhead cartridge. However, the ordinary worker will appreciate that the invention is equally applicable to other arrangements requiring a detachable fluid connection.
In
An input arm 20 is hinged to compression member 18. A compression lever 22 is fixed at an angle to the input arm 20. The input arm 20 and the compression lever 22 are part of a lever system described in greater detail below with reference to
As best shown in
When the fluid coupling disengages, the input arm 20 is rotated in the opposite direction to simultaneously decompress the annular seal 16 and retract the second conduit 14 from the first conduit 12. This coupling is configured establish a sealed fluid connection with the first conduit subjected to little or no insertion force. In light of this, the structure that the supports the first conduit is not overly flexed or bowed. This protects any components that are not robust enough to withstand structural deformation.
In
Referring to
When the compression member is at its point of maximum travel towards the cartridge, the compression lever 22 engages the second conduit (not shown). The compression lever 22 is dimensioned to hold the second conduit stationary relative to the first conduit as the input arm 20 continues to rotate and draw the compression member 18 back to compress the seal and establish the fluid seal (see
The coupling is shown forming a sealed fluid connection between one of the spouts 12 and the one of the second conduits 14. It will be appreciated that the coupling at the inlet and outlet manifolds are identical with the exception that the ink flows from the second conduit 14 to the spout 12 at the inlet manifold and in the opposing direction at the outlet manifold. For the purposes of this description, the coupling will be described at the inlet manifold. Accordingly, flexible tubing 52 feeds ink from an ink tank (not shown) to the second conduit 14. The shut off valve 30 in the second conduit 14 is being held open by the end of the spout 12. The ink flows into the spout 12 and down to the LCP channel molding 4 where it is distributed to the printhead ICs 31.
The coupling 10 is actuated by the actuator arm 56 hinged to the print engine chassis 42 at shaft 50. As discussed above the latch 40 (not shown in
When the printhead cartridge 38 is to be replaced, the latch (not shown) is lifted off the cartridge to automatically rotate the actuator arm 56 upwards, thereby lifting and retracting the input arm 20. The annular seal 16 is released when the compression lever 22 swings out of engagement with the surface 26. The second conduits and the corresponding spouts 12 now have a loose sliding fit and slide easily away from each other. With the compression member 18 and the spouts 12 completely disengaged, the user simply lifts the cartridge 38 out of the print engine 3.
The above embodiments are purely illustrative and not restrictive or limiting on the scope of the invention. The skilled worker will readily recognize many variations and modifications which do not depart from the spirit and scope of the broad inventive concept.
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|---|---|---|---|
| 20020163566 | Jang et al. | Nov 2002 | A1 |
| 20030020040 | Anderson | Jan 2003 | A1 |
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| Number | Date | Country | |
|---|---|---|---|
| 20090179968 A1 | Jul 2009 | US |
