Us005565900A
`
`United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,565,900
`
`Cowger et al.
`
`[45] Date of Patent:
`
`Oct. 15, 1996
`
`[54] UNIT PRJNT HEAD ASSEMBLY FOR
`[NKJET pR1NT1N(;
`
`[75]
`
`Inventors: Bruce Cowger; Donald B. Ouchida;
`-
`ggzgflt R‘ B°eS°"’ all of Comflhs’
`
`.
`Assignee. Hewlett-Packard Company, Palo Alto,
`Calif
`
`App]_ No_; 192,037
`
`Filed:
`
`Feb. 4, 1994
`
`.
`
`6
`
`...................................................... B41.l 2/155
`Int. Cl.
`.............................................................. .. 347/42
`U.S. Cl.
`Field of Search .................................. 347/42, 49, 50,
`347/36’ 37
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`.
`
`1/1983 Koto .......................................... 347/86
`4,368,478
`7/1933 ozawa et a]_
`4394559
`2/1984 Thomas
`4,433,341
`7/1984 Bangs et al.
`4,462,037
`10/1934 Sick,-Hg at 3]
`4,475,116
`2/1935 Buck et 31 _
`4,500,395
`4/1985 Terasawa
`4,510,510
`3/1936 an et al.
`4,577,200
`9/1986 Kamberg 6‘
`47614348
`4,620,20Q l0/1986 Koto et al.
`4 623 332
`12/1986 Mmumoto
`4’633’274
`12/1986 Mmuda
`4,635,073
`1/1937 Hanson
`4,680,859
`7/1987 Johnson ..
`4,683,481
`7/1987
`
`........................ 347/65
`9/1987 Chan et al.
`4,694,308
`4,712,172 12/1987 Kiyohara et al.
`.
`. 347/60
`4,746,935
`5/1988 Allen ........... ..
`.. 347/98
`
`--
`9/1988 Bake‘ at 31-
`4/7711295
`4,791,433 12/1933 Hanson etal.
`4,306,106
`2/1939 Mebane et al.
`4,814,786
`3/1989 Hoisington et al.
`4,847,630
`7/1989 Bhaskar etal.
`4,372,026 10,1989 Rasmussen et al
`4,372,027
`10/1939 Buskirk etal.
`4,917,236
`4/1990 Pollacek
`4,929,969
`5/1990 Mon-is ..... ..
`4,940,413
`7/1990 Chjlders et al.
`4,953,287
`9/1990 West et al.
`5,016,023
`5/1991 Chan et al.
`570497904
`9/1991 Nakamura et a1_
`5,091,737
`2/1992 Toganoh ct al.
`..
`5,448,274
`9/1995 Hirabayashi at al
`5,469,199 11/1995 Allen etal.
`FOREIGN PATENT DOCUMENTS
`
`' 347/87
`. 347/37
`. 439/77
`. 347/88
`. 347/63
`_ 347,56
`347/19
`. 223/110.1
`.. 347/37
`. 439/67
`. 29/611
`. 347/42
`_ 347/19
`. 347/42
`- 347/50
`347/42
`
`0376719A3
`
`.
`7/1990 European Pat. Off.
`OTHER PUBLICATIONS
`
`“Printhead Interconnect,” R. T. Buck; HP Journal, May
`1985.
`_
`_
`_
`_
`Pnmary Exammer—BenJarn1n R. Fuller
`Assistant Examirzer—Craig A. Hallacher
`
`ABSTRACT
`[57]
`Ink—jet pens having multiple print heads are manufactured
`with readily replaceable unit print head assemblies that
`facilitate testing of print head performance prior to complete
`assfimbly of the Pen-
`
`10 Claims, 5 Drawing Sheets
`
`HP 1004
` Page 1 of 10
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`

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`U.S. Patent
`
`Oct. 15, 1996
`
`Sheet 1 of 5
`
`5,565,900
`
`HP 1004
` Page 2 of 10
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`

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`U.S. Patent
`
`'
`
`Oct. 15,1996
`
`Sheet 2 of 5
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`5,565,900
`
`HP 1004
` Page 3 of 10
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`

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`Oct. 15, 1996
`
`Sheet 3 of 5
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`5,565,900
`
`'IVniunin
`KX“‘
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`HP 1004
` Page 4 of 10
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`

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`U.S. Patent
`
`5“,1f"C0
`
`6991
`
`Sheet 4 of 5
`
`5,565,900
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`HP 1004
` Page 5 of 10
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`

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`U.S. Patent
`
`Oct. 15, 1996
`
`Sheet 5 of 5
`
`5,565,900
`
`HP 1004
` Page 6 of 10
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`

`
`1
`UNIT PRINT HEAD ASSEMBLY FOR
`INK-JET PRINTING
`
`2
`FIG. 9 is a diagram showing one system for delivering a
`circulating ink supply to the unit print head assemblies of the
`pen.
`
`5,565,900
`
`TECHNICAL FIELD
`
`This invention pertains to ink-jet printing, and in particu-
`lar to modular-type manufacture of ink-jet printing pens,
`whereby a print head assembly is constructed as a unit and
`thereafter removably mounted to the pen body.
`
`BACKGROUND AND SUMMARY OF THE
`INVENTION
`
`Some ink-jet printers, such as manufactured by Hewlett-
`Packard Company under the designation Deskiet, include a
`cartridge or “pen” that is mounted to a carriage in the printer.
`The pen includes a body that defines a reservoir of ink, and
`a print head that is operated for ejecting minute ink drops
`onto paper that is advanced through the printer.
`Prior ink-jet pens have been constructed so that the print
`head is irremovably attached to the pen body,
`thereby
`preventing replacement of a print head without damage to
`the pen.
`Some ink-j et printer pens can be designed to include more
`than one print head. For example, a pen can be constructed
`to include a plurality of print heads that span across the
`entire width of a page that is advanced through the printer.
`In the event that such a multiple-print-head pen were
`manufactured using conventional techniques, the entire pen
`would have to be assembled before the printing character-
`istics of the print heads could be tested. A failure of one of
`the print heads, therefore, would ruin the entire pen and lead
`to expensive waste or re—work for repairing the pen.
`The present
`invention is directed to a construction
`whereby ink-jet printer pens have modular or unit print head
`assemblies that can be readily mounted to and removed from
`a pen body in the event that the assembly needs repair or
`replacement. Moreover, the print heads of an individual unit
`print head assembly may be fully tested before that assembly
`is joined with several other parts in manufacturing a pen.
`
`BRIEF DESCRIFIION OF THE DRAWINGS
`
`FIG. 1 is a perspective view of an ink-jet pen employing
`several unit print head assemblies made in accordance with
`the present invention.
`FIG. 2 is an enlarged, exploded view showing a unit print
`head assembly and part of the pen body to which the
`assembly is mounted.
`FIG. 3 is a perspective view showing the bottom of a unit
`print head assembly.
`FIG. 4 is a perspective view, partly cut away, showing an
`assembled ink-jet pen that
`incorporates unit print head
`assemblies.
`
`FIG. 5 is a bottom view similar to FIG. 3 but showing the
`assembly with part of the bottom plate cut away.
`FIG. 6 is a top plan view diagram illustrating an ink
`circulation path through the unit print head assembly of the
`present invention.
`FIG. 7 is an enlarged detail view, partly in section,
`showing a portion of a print head that is carried by the unit
`print head assembly.
`. FIG. 8 is a detail View of an alternative mechanism for
`mounting a print head assembly to a pen.
`
`DETAILED DESCRIPTION OF A PREFERRED
`EMBODIIVIENT
`
`FIG. 1 depicts a pen 20 for use with an inkjet printer. The
`pen 20 includes a plurality of unit print head assemblies 22
`(hereafter occasionally referred to as “assemblies,” for con-
`venience) constructed in accordance with the present inven-
`tion. The pen 20 includes a substantially rigid body 24 to
`which the assemblies 22 are removably mounted as
`explained more fully below.
`In one embodiment,
`for
`example, the assemblies 22 are mounted to the pen body by
`threaded fasteners 23 (FIG. 4).
`The pen body 24 can be mounted to a printer by any of a
`number of means in association with conventional mecha-
`nisms for advancing paper 28 immediately adjacent to the
`assemblies 22 so that ink drops can be ejected onto the paper
`from print heads carried by the assemblies. The pen body 24
`includes a ribbon-type multiconductor 26 for conveying
`control signals to the assemblies, as described more fully
`below.
`
`When the assemblies 22 are mounted to the pen body 24
`they are placed in fluid communication with a supply of ink.
`As shown in FIG. 1, the ink supply may be conducted to the
`pen body 24 from a remote source via an inlet conduit 32.
`The pen body 24 is constructed to define a manifold for
`conducting and distributing supply ink to each of the assem-
`blies 22. In a preferred embodiment, supply ink that is not
`expelled by the print heads during printing is removed from
`the manifold and circulated back to the supply via outlet
`conduit 34.
`
`With reference to FIGS. 2-5, the particulars of a unit print
`head assembly 22 and the pen body 24 to which it is
`mountable will now be described.
`
`A print head assembly 22 includes a carrier 40 made of
`molded plastic. Alternatively, ceramic, die-cast metal, or
`machined metal may be used. The carrier 40 carries print
`heads 50 (FIG. 4). In this regard, a number (for example,
`eight) of oblong recesses 46 are formed in a top, planar
`surface 48 of the carrier 40. A print head 50 that generally
`corresponds to the shape of a recess 46 fits within the recess
`and is mounted thereto, such as by bonding with adhesives.
`In a preferred embodiment, each carrier 40 includes two
`rows of print heads 50, with one row of print heads ofl°set
`relative to the other row of print heads so that, in the
`direction of paper movement (FIG. 1), there are no gaps
`between the nozzles 57 of the print heads in one row and the
`nozzles of print heads in the other row. This olIset relation-
`ship defines a 90° notch at each end 41 of the carrier.
`The outer surface 52 of the print head 50 and the surface
`48 of the carrier 40 are covered with a flexible circuit 54 that
`also wraps around the rounded long edges 55 of the carrier.
`The circuit 54 also extends over part of the carrier bottom
`plate 85 (FIG. 3), as described more fully below.
`The flexible circuit 54 may be staked to the carrier 40.
`Specifically, the circuit is applied to the exterior surface of
`the carrier under pressure and heat sufficient for causing
`plastic flow of the plastic carrier so that the underside of the
`flexible circuit 54 is joined to the carrier.
`The part of the circuit 54 that covers the upper surface 52
`of each print head 50 has defined through it two rows of
`minute nozzles 57. Each individual nozzle is in fluid com-
`
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`3
`munication with a firing chamber 98 in the print head (FIG.
`7). Each firing chamber 98 has associated with it a thin-film
`resistor 94 that is selectively driven (heated) with suflicient
`current for instantaneously vaporizing some of the ink that
`enters the chamber, thereby forcing a drop of ink through the
`nozzle.
`
`In apreferred embodiment, the flexible circuit 54 com-
`prises a strip of polyirnide, the underside of which (that is,
`the side of the strip that is staked to the carrier 40) has
`bonded to it a multitude of copper traces (not shown), each
`trace being joined at one end to an embossed, conductive
`contact pad 62 (FIG. 3). The contact pads are exposed on the
`exterior surface of the circuit 54 on the underside of the print
`head assembly 22. The contact pads connect with corre-
`sponding contacts mounted on the pen bodies as described
`more fully below.
`The other ends of the traces on the circuit terminate in free
`ends or beams that are welded to corresponding conductors
`carried on the print head 50. In this regard, windows 64 are
`provided through the flexible circuit 54. The beams of the
`traces protrude into the windows and are exposed there for
`welding to the conductors on the print head. A method and
`associated apparatus for attaching a flexible circuit to a pen
`body and print head is described in U.S. patent application
`Ser. No. 07/737,623, owned by the assignee of the present
`application and herein incorporated by reference.
`With particular reference to FIG. 4, each recess 46 in the
`carrier 40 is constructed to be generally wider than the print
`‘head 50 received therein, except at the ends of the recess,
`where opposing alignment features 70 protrude inwardly
`toward the longitudinal center line of the recess. The dis-
`tance between the pair of alignment features 70 at each end
`of the recess substantially matches the width of the print
`head 50. As a result, these features secure the print head with
`its longitudinal center line matching that of the recess.
`The long side edges of the print head 50 are spaced from
`the corresponding long side edges of each recess 46. This
`spaced relationship, therefore, defines an elongated first ink
`passageway 72 extending the substantial length of one side
`of the print head 50, and a corresponding second ink
`passageway 74, extending along the substantial length of the
`other side of the print head (FIG. 4). It will be appreciated
`that with the flexible circuit 54in place, the passageways 72,
`74 are substantially enclosed along their length by the print
`head 50, carrier 40, and the underside of the circuit 54.
`At the end of each passageway 72, 74, there is formed
`through the carrier a via 84 (FIGS. 4 and 5). The viae 84
`conduct the flow of ink in the associated ink passageway 72
`or 74 between that passageway and a corresponding one of
`a series of ducts 91 that are defined by the underside of the
`carrier 40 and the bottom plate 85. In particular, the under-
`side of the carrier 40 is formed to include downwardly
`protruding ribs 87, best shown in FIG. 5. The lowermost
`edges of the ribs are in a common plane so that the ribs
`evenly rest on the upper surface 86 (FIG. 4) of the bottom
`plate 85. The bottom plate 85 may be formed of any suitably
`rigid material, such as molded plastic.
`.
`The downwardly protruding ribs 87 define in combination
`with the surface 86 of the bottom plate the ducts 91 that
`connect certain viae 84 and the recesses 46 so that ink flows
`through passageways 72, 74 over a continuous path from
`print head to print head. The top view, simplified (print
`heads omitted) diagram of a carrier, FIG. 6, shows by arrows
`93 the continuous path of ink through the ducts 91, pas-
`sageways 72, 74, and viae 84.
`The carrier 40 also has protruding from its underside a set
`of annular, spaced-apart bosses 47 that protrude from the
`
`4
`bottom plate 85. The bosses 47 provide a mechanism for
`mounting the print head assembly to the pen body, as
`described more fully below.
`Two ports 83, 92 (FIG. 3) are formed in the bottom plate
`85. One port 83 aligns with a rounded end 95 (FIG. 6) of a
`duct 91 in the carrier and, therefore, forms an inlet to permit
`ink to enter the series of connected ducts 91, viae 84 and
`passageways 72, 74. The port 83 aligns with and seals in
`fluid communication with a manifold "aperture 81 formed in
`the pen body 24 in communication with an inlet manifold
`101 that is filled with ink via supply conduit 32 (FIG. 4).
`The inlet manifold 101 is defined by the pen body 24 as
`an elongated conduit or chamber extending along the length
`of the pen body 24. An aperture 81 is formed in the pen body
`at the inlet port 83 of each assembly that is mounted to the
`pen body. Preferably, an elastomeric 0-ring 89 is secured in
`a countersunk portion of each manifold aperture 81 to be
`compressed between the body and the carrier to provide a
`tight seal therebetween.
`Similarly, outlet port 92 aligns with the rounded end 100
`of the last in the series of ducts 91. The outlet port 92 seals
`in fluid communication with another aperture on the pen
`body (not shown) for directing ink that flows out of that port
`92 into an outlet manifold 103. The outlet manifold 103
`collects ink from each outlet port 92. Ink is removed from
`manifold 103 via conduit 34.
`
`FIG. 7 depicts ir1 greatly enlarged detail the relationship
`between print head firing chambers 98 and the first ink
`passageway 72. Specifically,
`the print head 50 may be
`constructed to include a substrate layer 97 that carries on it
`a number of thin-film resistors 94, one resistor underlying a
`corresponding nozzle 57 in the flexible circuit 54. Each
`resistor 94 is electrically connected with a discrete conduc-
`tive member (not shown) that is connected with a corre-
`sponding end of a copper trace carried by the flexible circuit
`as mentioned above.
`
`A thin, barrier layer 96 of polymeric material covers the
`substrate and is shaped by, for example, a photolithographic
`process to define the small—volume firing chambers 98 that
`surround each resistor 94. The outermost edges of the barrier
`96 are shaped to define for each chamber 98 an entry region
`99 through which ink may flow into the firing chamber. A
`portion of the ink is vaporized by the resistor, the resultant
`fluid expansion in the chamber ejecting a drop of ink through
`the corresponding nozzle 57 onto passing paper 28.
`As can be seen upon review of FIG. 7,
`the first ink
`passageway 72 is oriented to be in fluid communication with
`the print head so that ink is continuously flowing immedi-
`ately adjacent the entry regions 99 of each firing chamber.
`The print head construction is generally symmetrical
`about the longitudinal center line of the print head 50.
`Accordingly, it will be appreciated that the relationship of a
`second ink passageway 74 and the print head firing cham-
`bers on the opposing side of the print head provide the same
`ink flow across the firing chambers 98 as that of the first ink
`passageway 72.
`Although the print head and ink circulation system just
`described may be a preferred embodiment,
`it is contem-
`plated that print heads having firing chamber entrances fed
`from a charmel in the center, underside of the print head may
`also be used with a carrier of the present invention. The ink
`passageways of the carrier would be shaped to flow to
`central channels. Moreover, the print heads used with the
`present invention need not be supplied with circulating ink.
`T‘urning now to the particulars of the pen body portion to
`which the assemblies 22 are mounted, with reference to
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`5
`
`FIGS. 2 and 4, the pen body includes a mounting location
`that comprises a recessed, planar surface 102 defined
`between opposing, upwardly protuding lips 104, 106 that
`extend along the length of the pen body. Each short edge of
`the pen body includes a generally L-shaped end piece 108
`that is shaped to conform to the notched end of the print head
`assembly 22, as best shown in FIG. 4.
`The above-mentioned ribbon—type multiconductor 26 is
`attached to the surface 102 and includes clearance holes
`formed therethrough so as not to block the assembly bosses
`94 or inlet and outlet ports 83, 92. At locations underlying
`the embossed contact members 62 on the print head assem-
`bly underside (see FIG. 3), the multiconductor 26 carries
`embossed contacts 110 at the termini of the conductors
`formed in the multiconductor 26.
`
`5
`
`Whenever the print head assembly is mounted to the pen
`body, therefore, the embossed contacts 62 on the assembly
`22 press against, and, hence, electrically connect with the
`aligned embossed contacts 110 on the multiconductor 26. As
`a result, there is defined a continuous conductive path for
`conducting electronic control signals between the contacts
`110 and the circuit member conductors, the control signals
`being provided by the printer controller for firing the resis-
`tors 94 as mentioned above.
`
`threaded fasteners 23 may be
`As mentioned above,
`employed for removably mounting a print head assembly 22
`to a pen body 24. In this regard, the pen body may be formed
`to include a sleeve 112 (FIG. 4) through which a threaded
`fastener may extend. The threaded end of the fastener 23
`extends into the sleeve to engage an internally threaded boss
`47 of an assembly, which boss fits through a clearance hole
`in the multiconductor 26 and protrudes into the bore of the
`sleeve 112. The fastener 23 is sized so that when threaded
`tightly into the boss 47 the assembly is held firmly against
`the pen body. It will be appreciated that although only one
`fastener is shown in FIG. 4 there is provided a fastener and
`sleeve for each of the four threaded bosses 47 of each
`assembly 22.
`Numerous alternative mechanisms may be employed for
`mounting a print head assembly to a pen body. For example,
`as shown in FIG. 8, a print head assembly 22 may be snap-fit
`into a pen body 224 that has protruding lips 204, 206 shaped
`to generally conform to the rounded long edges 55 of the
`carrier. Accordingly, the assembly 22 is pressed between the
`lips, which yield slightly to permit the widest portion of the
`assembly to pass between the narrowest portion of the lips.
`The pen body lips thereafter resile to firmly hold the
`assembly in place against the pen body 224.
`Notches 220 are formed in spaced-apart locations along
`the length of one of the lips 204 to permit a thin fiat lever to
`fit through the notch and part way under the assembly,
`thereby to pry the assembly 22 from the pen body 224.
`It will be appreciated by one of ordinary skill in the art
`that a testing device conforming to a pen body (24 or 224)
`for holding a single print head assembly 22 can be con-
`structed for testing individual assemblies 22 before they are
`joined with several other assemblies to make a complete
`pen.
`
`Any of a number of systems may be employed for
`supplying circulating ink to a print head assembly via
`conduits 32, 34. One preferred supply system is shown in
`FIG. 9. In this embodiment,
`the pen body 24 includes
`internal partitions 205 that define a discrete inlet and outlet‘
`manifold pair underlying each assembly 22. In this regard,
`the embodiment of FIG. 9 is dilferent from the embodiment
`described above in that the earlier-described embodiment
`
`6
`includes a single manifold pair 201, 203 that extends across
`a substantial length of the pen body across all of the print
`head assemblies 22.
`As shown in FIG. 9, each inlet manifold 201 receives ink
`from a connected supply conduit 232. An outlet manifold
`discharges ink through an outlet conduit 234. Ink is supplied
`to each supply conduit 232 from a supply 210 that comprises
`any container suitable for storing a supply of ink. The outlet
`conduits 234 are tied to a return line 238 to which is
`connected a diaphragm pump 240 that provides a pressure
`gradient for generating the ink flow through the system in a
`circulating manner as depicted.
`In a preferred embodiment, the fluid pressure within the
`system is maintained slightly below ambient so that ink will
`not leak from the print head nozzles 57 when the firing
`chambers are inactive. It is desirable, however, to regulate
`the pressure within the system so that the partial vacuum or
`back pressure established in the system does not become so
`high as to prevent the drop ejection forces generated in the
`firing chambers from overcoming the back pressure. To this
`end, a vacuum regulator 212 is connected to the return line
`238 (or to any other location in the system) to permit the
`limited entry of ambient air into the system in the event that
`pressure within the system drops below a predetermined
`threshold level. Preferably,
`the vacuum regulator 212 is
`adjustable for changing the threshold level as necessary.
`Interconnected between the supply container 210 and
`each inlet conduit 232 is a normally closed valve 207. The
`valves may be any suitable electronically controlled valves
`that are normally closed when the printer is not operating.
`The closed valves, therefore, tend to maintain the partial
`vacuum or back pressure within the associated print head
`assembly 22 even if the pen 20 is tipped out of its normal
`position, which tipping would impart a pressure head in the
`assembly tending to cause the lower nozzles to leak and the
`upper nozzles to become de-primed. In a preferred embodi-
`ment, the length of a print head assembly from one end 41
`to another (that is, the length of a continuous passageway
`filled with ink) is less than the back pressure (measured in
`inches of water column) to be maintained in the print head
`assembly so that in instances where one end of the pen is
`tipped directly above the other end of the pen, the resultant
`pressure head in an individual assembly will not exceed the
`back pressure maintained within the assembly by the closed
`valve.
`
`It is contemplated that the above-described manifolds are
`not required and that inlet conduits 32, 232 can be directly
`connected to the inlet ports 83 of each assembly 22, and the
`outlet conduits 34, 234 may be similarly connected directly
`to outlet ports 92 of the assemblies.
`Although the foregoing invention has been described in
`connection with preferred and alternative embodiments, it
`will be appreciated by one of ordinary skill that various
`modifications and variations may be substituted for the
`mechanisms and method described here without departing
`from the invention as defined by the appended claims and
`their equivalents.
`For example, a preferred embodiment described above is
`illustrated in FIG. 2 with four carriers, each carrier being
`sized to carry eight print heads. It is contemplated, however,
`that the carrier and pen body configuration is readily adapt—
`able to more or fewer carriers that carry one or any number
`of print heads.
`The invention claimed is:
`1. A pen for an ink-jet printer, comprising:
`a print head assembly, including:
`
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`5,565,900
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`7
`a carrier having an outer side and an inner side;
`at least one print head mounted to the carrier, the print
`head having a plurality of chambers defined therein,
`the print head also having firing means associated
`with each chamber for expelling ink drops from the
`chambers;
`the carrier defining a passageway in fluid communica-
`tion with the chambers, the passageway including an
`inlet port extending through the inner side and
`through which port ink may flow into the passage-
`way to the chambers;
`a circuit member attached to the carrier and having
`conductors for conducting control signals to the
`firing means,
`the firing means responsive to the
`control signals for expelling ink drops from the
`chambers;
`
`15
`
`a pen body having a mounting surface including:
`electrical contacts mounted to the pen body;
`a conduit defined by the pen body for conducting ink
`through the conduit, the conduit including an aper-
`ture through the mounting surface; and
`mounting means for removably mounting the carrier
`inner side adjacent to the pen body mounting surface
`so that the conductors and the contacts join to form
`a junction to provide continuous paths for conduct-
`ing control signals between the contacts and the
`circuit member conductors and so that the aperture
`and inlet port join to form a junction and are in fluid
`communication.
`2. The pen of claim 1 comprising more than one print head
`assembly as defined in claim 1, and wherein the mounting
`means is for removably mounting more than one print head
`assembly to the pen body so that the conductor and the
`contacts join to provide continuous paths for conducting
`control signals between the contacts and the conductors, and
`so that
`the conduit and inlet ports are joined in fluid
`communication.
`3. The pen of claim 1 wherein the mounting means
`comprises removable fasteners connected between the car-
`rier and pen body for removal of the mounted print head
`assembly without damage to the pen body.
`4. The pen of claim 1 wherein the mounting means
`includes:
`
`resilient snap members protruding from the pen body to
`force together the circuit member conductors and the
`pen body contacts so that the junction between the
`conductors and the contacts is made.
`5. The pen of claim 1 wherein the carrier includes an
`outlet port through which ink that flows into the passageway
`may flow out of the passageway.
`
`8
`6. The pen of claim 1 further comprising a seal member
`attached between the carrier and pen body for sealing the
`joined aperture and inlet port.
`7. The pen of claim 1 further comprising:
`a mounting portion defined by the pen body and to which
`is mounted a plurality of carriers;
`ink delivery means for supplying ink from a supply to all
`carriers that are mounted to the pen body,
`the ink
`delivery means including conduits connected between
`the supply and each carrier; and
`a valve connected to each conduit, each valve being
`operable for opening and closing the conduit.
`8. A method of making a pen for an ink-jet printer,
`comprising the steps of:
`providing a carrier having at least one print head mounted
`thereto wherein the print head has a plurality of cham-
`bers defined therein for receiving ink, the print head
`also having firing means associated with each chamber
`for expelling ink drops from the chambers;
`defining in the carrier a passageway to be in fluid com-
`munication with the chambers, the passageway includ-
`ing an inlet port through which ink may flow into the
`passageway to the chambers;
`the circuit
`attaching a circuit member to the carrier,
`member having conductors for conducting control sig-
`nals to the firing means, the firing means responsive to
`the control signals for expelling ink drops from the
`chambers, the conductors terminating in a plurality of
`contact members;
`providing a pen body that has exposed electrical contacts
`mounted thereto and a conduit defined by the pen body
`for conducting ink from a supply through the conduit;
`and
`
`removably mounting the carrier to the pen body so that the
`contact members and the electrical contacts are pressed
`together to provide continuous paths for conducting
`control signals between the electrical contacts and the
`conductors, and so that the conduit and inlet port are
`joined to form a junction and are in fluid communica-
`tion.
`9. The method of claim 8 wherein the attaching step
`includes attaching the circuit member so that the contact
`members are exposed for pressure connection with the
`electrical contacts on the pen body when the carrier is
`mounted to the pen body.
`10. The method of claim 8 including the step of providing
`a seal member for sealing the junction of the conduit and
`inlet port.
`
`HP 1004
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