Printhead carrier for an imaging apparatus

An imaging apparatus includes a printhead carrier for mounting a printhead cartridge. The printhead carrier includes a carrier back wall having an upper portion. A back portion of a printhead cartridge cradle is connected to the carrier back wall. A first proximal end of a latch lever is pivotably attached to a front portion of the printhead cartridge cradle. The latch lever has at least one cam follower, with each cam follower being located near the first distal end of the latch lever. A second proximal end of a carrier lid is pivotably attached to the upper portion of the carrier back wall. Each cam of the carrier lid is formed near a second distal end of the carrier lid, and each cam is positioned for progressive engagement by a corresponding cam follower as the latch lever is moved from an open position toward a latched position.

CROSS REFERENCES TO RELATED APPLICATIONS

REFERENCE TO SEQUENTIAL LISTING, ETC.

BACKGROUND

1. Field of the Invention

The present invention relates generally to an imaging apparatus, and more particularly to those having or using a printhead carrier.

2. Description of the Related Art

In the prior art, an imaging apparatus, such as an ink jet printer, forms an image on a print medium, such as paper, by applying ink to the print medium. Such an ink jet printer includes a reciprocating printhead carrier that transports one or more ink jet printhead cartridges across the print medium along a bi-directional scanning path defining a print zone of the printer. An ink jet printhead cartridge, for example, includes both an ink tank containing ink and an ink jet micro-fluid ejection device, i.e., ink jet printhead, for selectively ejecting the ink. Each ink jet printhead cartridge is mounted to the printhead carrier.

In the printing industry, there is an increasing desire to reduce size. Accordingly, every component is under scrutiny for optimal performance with minimal size. It is typical for printers to have carrier latches that hold their respective printhead cartridges in place on the printhead carrier. However, such carrier latches may involve several moving parts that often complicate the process of latching. Also, such carrier latches are designed such that a lid swings upward to permit the printhead cartridge to be loaded from the top. Further, such prior carrier latches may be oversized, as well as inefficient from a usability perspective, and provide little or no mechanical advantage to the user during latching.

SUMMARY OF THE INVENTION

The present invention, in one form thereof, is directed to an imaging apparatus. The imaging apparatus includes a guide frame, and a printhead carrier coupled to the guide frame for mounting a printhead cartridge. The printhead carrier includes a carrier back wall having an upper portion and a lower portion. A printhead cartridge cradle has a front portion and a back portion, the back portion being connected to the carrier back wall. A latch lever has a first proximal end and a first distal end, the first proximal end being pivotably attached to the front portion of the printhead cartridge cradle. The latch lever has at least one cam follower, with each cam follower being located near the first distal end. A carrier lid has a second proximal end, a second distal end, at least one cam, an interior and an exterior. The second proximal end is pivotably attached to the upper portion of the carrier back wall. Each cam is formed at the exterior near the second distal end, and each cam is positioned for progressive engagement by a corresponding cam follower as the latch lever is moved from an open position toward a latched position.

The present invention, in another form thereof, is directed to a printhead carrier for mounting a printhead cartridge. The printhead carrier includes a carrier back wall having an upper portion and a lower portion. A printhead cartridge cradle has a front portion and a back portion, the back portion being connected to the carrier back wall. A latch lever has a first proximal end and a first distal end, the first proximal end being pivotably attached to the front portion of the printhead cartridge cradle. The latch lever has a first cam follower spaced apart from a second cam follower. Each of the first cam follower and the second cam follower is located near the first distal end. A carrier lid has a second proximal end, a second distal end, a first cam, a second cam, an interior and an exterior. The second proximal end is pivotably attached to the upper portion of the carrier back wall. The first cam and the second cam are formed at the exterior near the second distal end. The first cam is positioned for progressive engagement by the first cam follower and the second cam is positioned for progressive engagement by the second cam follower as the latch lever is moved from an open position toward a latched position.

DETAILED DESCRIPTION

In addition, it should be understood that some embodiments of the invention may include both hardware and electronic components of modules that, for purposes of discussion, any be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software. As such, it should be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be utilized to implement the invention. Furthermore, and as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention and that other alternative mechanical configurations are possible.

Referring toFIG. 1, there is shown a diagrammatic depiction of an imaging system10embodying the present invention. Imaging system10may include a host12and an imaging apparatus14. Imaging apparatus14communicates with host12by way of a communications link16. Communications link16may be established by a direct cable connection, wireless connection or by a network connection such as for example an Ethernet local area network (LAN). As used herein, the term “imaging apparatus” is a device that forms a printed image on a print medium.

Alternatively, imaging apparatus14may be a standalone unit that is not communicatively linked to a host, such as host12. For example, imaging apparatus14may take the form of an all-in-one, i.e., multifunction, machine that includes standalone copying and facsimile capabilities, in addition to optionally serving as a printer when attached to a host, such as host12.

Host12may be, for example, a personal computer including an input/output (I/O) device, such as keyboard and display monitor. Host12further includes a processor, input/output (I/O) interfaces, memory, such as RAM, ROM, NVRAM, and a mass data storage device, such as a hard drive, CD-ROM and/or DVD units. During operation, host12may include in its memory a software program including program instructions that function as an imaging driver, e.g., printer driver software, for imaging apparatus14. Alternatively, the imaging driver may be incorporated, in whole or in part, in imaging apparatus14.

In the embodiment ofFIG. 1, imaging apparatus14includes a controller18, a print engine20and a user interface22.FIG. 2shows a side view of imaging apparatus14, in the form of a compact ink jet printer.

Controller18includes a processor unit and associated memory, and may be formed as an Application Specific Integrated Circuit (ASIC). Controller18communicates with print engine20by way of a communications link24. Controller18communicates with user interface22by way of a communications link26. Communications links24and26may be established, for example, by using standard electrical cabling or bus structures, or by wireless connection.

Print engine20may be, for example, an ink jet print engine configured for forming an image on a sheet of print media28, such as a sheet of paper, transparency or fabric. Print engine20may include, for example, a guide frame29and a reciprocating printhead carrier30slidably coupled to guide frame29. Printhead carrier30is mechanically and electrically configured to mount and carry at least one printhead cartridge32. During a printing operation, guide frame29guides printhead carrier30back and forth along a bi-directional main scan path34, and in turn printhead carrier30transports printhead cartridge32in a reciprocating manner over an image surface of the sheet of print media28.

FIG. 2shows imaging apparatus14with printhead carrier30in an open position so as to receive printhead cartridge32. Printhead cartridge32is installed from the front of imaging apparatus14toward the back of imaging apparatus14in a direction36A. Direction36B is a direction opposite to direction36A. Directions36A and36B are substantially perpendicular to bi-directional main scan direction, i.e., axis,34(seeFIG. 1). Since imaging apparatus14is configured to facilitate front loading of printhead cartridge32, electronic components, such as a printed circuit board38(shown in dashed lines) including controller18, may be positioned at a location above printhead carrier30, thereby contributing to a reduction of the footprint of imaging apparatus14when compared to top loading designs.

FIGS. 3A and 3Bshow a front view, and a bottom perspective view, respectively, of printhead cartridge32. Printhead cartridge32includes a reservoir body40, a top cover42and an ink jet printhead44. Reservoir body40includes a first side40-1, a second side40-2, a front side40-3, a back side40-4, and a bottom side40-5. Electrical connections are made to ink jet printhead44from controller18via a tape automated bond (TAB) circuit46located on back side40-4of printhead cartridge32.

Printhead cartridge32includes a plurality of positioning datums, individually identified as datums41A-1,41A-2,41A-3,41B-1,41B-2, and41C. Datums41A-1,41A-2, and41A-3are located on side40-2. Datum41B-1is located on an upper lip just below top cover42at back side40-4. Datum41B-2is located on bottom side40-5near front side40-3. Datum41C is located on an upper portion of back side40-4adjacent to datum41B-1. Datums41A-1,41A-2,41A-3,41B-1,41B-2, and41C may, for example, be in the form of raised surfaces, and are designed to be engaged by corresponding datums in printhead carrier30.

Ink is contained in reservoir body40, and top cover42completes the enclosure to contain the ink. Fluid passageways (not shown) provide one or more paths for ink to flow from reservoir body40to ink jet printhead44. Reservoir body40includes a pair of parallel elongate guide members48, individually identified as guide member48-1and guide member48-2. Guide member48-1and guide member48-2extend longitudinally along opposite sides40-1,40-2of reservoir body40.

Referring now to FIGS.4and5A-5D, printhead carrier30includes a carrier back wall50, a printhead cartridge cradle52, a latch lever54and a carrier lid56.

Carrier back wall50has an upper portion50-1and a lower portion50-2. A set of electrical contacts58are provided on carrier back wall50. The set of electrical contacts58are communicatively coupled to controller18, such as by a multi-conductor cable. The set of electrical contacts58provide electrical power and signal communication to TAB circuit46when printhead cartridge32is installed in printhead carrier30.

Printhead cartridge cradle52has a front portion52-1and a back portion52-2. Back portion52-2is connected carrier back wall50. Printhead cartridge cradle52includes positioning datums53A-1,53A-2,53A-3on a side wall thereof, and a datum53B-2located on a bottom portion thereof, which are positioned to engage corresponding datums41A-1,41A-2,41A-3, and41B-2of printhead cartridge32. Carrier back wall50includes positioning datums53B-1and53C positioned to correspondingly engage datums41B-1and41C of printhead cartridge32. The datums of printhead carrier30define absolute locating positions for positioning printhead cartridge32in printhead carrier30.

Latch lever54has a proximal end54-1and a distal end54-2. Proximal end54-1of latch lever54is pivotably attached to front portion52-1of printhead cartridge cradle52along a pivot axis60. Latch lever54has a first cam follower62-1and a second cam follower62-2. Each of cam followers62-1,62-2are located near distal end54-2, and are co-axially arranged along an axis64. Axis64is parallel to pivot axis60. Attached to latch lever54is a leaf spring65positioned to engage front side40-3of printhead cartridge32.

Each cam66-1,66-2is formed at exterior56-4of carrier lid56near distal end56-2. Cam66-1and cam66-2are oriented to be parallel, and each extends in direction36A from distal end56-2of carrier lid56to proximal end56-1of carrier lid56. In one embodiment, for example, the spacing between cam66-1and cam66-2in direction34is designed to be sufficient such that printhead cartridge32may be received between cam66-1and cam66-2. Each cam66-1,66-2is positioned for progressive engagement by a corresponding cam follower62-1,62-2, respectively, of latch lever54as latch lever54is moved from a full open position70(seeFIGS. 2 and 4) toward a latched position72(seeFIG. 5D). Carrier lid56pivots in an angular range of 10 degrees to 15 degrees, e.g., from horizontal, when carrier lid is moved from latched position72(seeFIG. 5D) to full open position70(seeFIGS. 2 and 4).

Each cam66-1and66-2has an identical a cam profile P, i.e., shape, that beings at distal end56-2of carrier lid56and ends at a corresponding detent74-1and detent74-2, respectively, formed at exterior56-4at a central region76(seeFIG. 5A) of carrier lid56that is between proximal end56-1and distal end56-2of carrier lid56. Each detent74-1,74-2is sized, shaped and positioned to receive a corresponding cam follower62-1,62-2, respectively, to define the location of latched position72, as shown inFIG. 5D.

Carrier lid56further includes a pair of elongate guide rails, individually identified as guide rail80-1and guide rail80-2formed in interior56-3of carrier lid56. Guide rails80-1,80-2are oriented to be parallel, and each extends in direction36A from distal end56-2of carrier lid56to proximal end56-1of carrier lid56to guide printhead cartridge32toward carrier back wall50as printhead cartridge32is loaded into printhead carrier32. Guide rail80-1is spaced apart from guide rail80-2in a direction perpendicular to direction36A, e.g., is spaced apart in a direction parallel to pivot axis68, i.e., in bi-directional main scan direction34. The spacing is designed to be sufficient such that printhead cartridge32may be received between first guide rail80-1and second guide rail80-2. Accordingly, guide member48-1and guide member48-2of printhead cartridge32are slidably engaged by guide rail80-1and guide rail80-2of carrier lid56as printhead cartridge32is loaded into printhead carrier30.

During a cartridge loading operation, a user inserts the guide members48-1and48-2of printhead cartridge32onto the pair of elongate guide rails80-1,80-2in carrier lid56. The user then contacts latch lever54and rotates latch lever54toward carrier back wall50. At this time, leaf spring65of latch lever54engages front side40-3of printhead cartridge32and moves printhead cartridge32along the pair of elongate guide rails80-1,80-2in carrier lid56into contact with positioning datum53C on carrier back wall50of printhead carrier30as latch lever54is moved from open position70toward latched position72. Simultaneously, cam followers62-1,62-2of latch lever54engage and ride along the profile P of corresponding cams66-1,62-2, respectively, to force carrier lid56to rotate downwardly toward printhead cartridge cradle52. During this latching operation, the engagement of cam followers62-1,62-2of latch lever54with the arc-shaped cam profile P of the corresponding cams66-1,66-2, respectively, of carrier lid56provides a mechanical advantage to the user, thereby requiring minimal force to be applied by the user during the latching operation.

As carrier lid56rotates downwardly toward printhead cartridge cradle52, leaf spring69of carrier lid56engages top cover42of printhead cartridge32and moves printhead cartridge32into contact with positioning datums53B-1and53B-2on printhead cartridge cradle52when latch lever54is moved from open position70toward latched position72. A cantilever spring82in printhead cartridge cradle52forces printhead cartridge32into engagement with datums53A-1,53A-2and53A-3on the side wall thereof.

When printhead cartridge32is moved into contact with positioning datums53B-1and53B-2on printhead cartridge cradle52, guide members48-1and guide member48-2of printhead cartridge32are transversely disengaged from guide rail80-1and guide rail80-2of carrier lid56, respectively. Leaf spring65of latch lever54continues to engage front side40-3of printhead cartridge32to hold printhead cartridge32against the positioning datums on carrier back wall50of printhead carrier32with a compression force when latch lever54is in latched position72.

Printhead cartridge installation is complete when cam followers62-1,62-2engage detents74-1,74-2, respectively, of carrier lid56, as shown inFIG. 5D.

During a printhead cartridge removal operation, a user applies a downward force on a actuator surface56-5of carrier lid56to cause latch lever54to be released from carrier lid56by releasing each cam follower62-1,62-2from its corresponding detent74-1,74-2, respectively, of carrier lid56. In turn, leaf spring65of latch lever54extends from the compressed state to propel latch lever54to open position70to expose front side40-3of printhead cartridge32to facilitate extraction of printhead cartridge32in a direction36B opposite to direction36A, i.e., in a direction away from carrier back wall50. Also, at this time a torsion spring84causes carrier lid56to rotate upwardly at an angle of about 12 degrees from horizontal, thereby lifting printhead cartridge32from printhead cartridge cradle52through the engagement of guide rails80-1,80-2of carrier lid56with the corresponding guide members48-1,48-2of printhead cartridge32. The user may then grasp the opposing side walls40-1,40-2of printhead cartridge32(seeFIG. 3A) and pull printhead cartridge32in a generally lateral direction36B until printhead cartridge32is disengaged from the guide rails80-1,80-2of carrier lid56.

With the embodiment described above, the latching mechanism of the printhead carrier is as much as 29 percent smaller than some prior designs. Also, user forces needed to latch the printhead carrier have been reduced considerably, in some instances by as much as approximately 200 percent.

While the embodiment described above is directed to an exemplary single printhead cartridge carrier, those skilled in the art will recognize that the concepts of the present invention may be easily applied to a multiple printhead cartridge environment.

The foregoing description of methods and an embodiment of the invention has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modification and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the claims appended hereto.