~304983 PRINTHEAD-CARRIAGE ALI~NM~NT AND EL~CTRICAL
INTERCONNECT LOCK-IN M~CHANISM
1 TECHNICA~ F~ELD
The present lnvention relates to ln~-~et prlnters, and, more partlcularly, to allgnment Or the prlnthead and carriage and an electrlcal lnterconnect lock-ln mechanlsm for controllln~ the prlnthead.
BACKGROUND ART
In lnk-Jet prlntln~ technology, a prlnthead, com-prlsln~ a plurallty of nozzles ln a nozzle plate, 18 fluldlcally assoclated wlth a reservolr of lnk. The prlnthead 18 mounted on one end of a prlnt cartrld~e and the reservolr ls provlded lnside the cartrld~e.
An lnterconnect means 18 provlded, whlch carrles electrlcal slgnals from a mlcroprocessor ln the prlnter to the prlnthead. For thermal lnk-Jet prlnter~, these slgnals provlde a current to reslstors assoclated wlth the nozzles and thus control the heatln~ of speclflc reslstors, whlch ln turn form droplets of lnk. The droplets of lnk are expelled through the nozzles toward a prtnt ~edlum, such as paper. The partl~cular pattern of reslstor hcatlng controls the pattern of characters formed on the prlnt medlum.
2S The prlnt cartrldge 18 supported ln a carrlage, whlch 18 adapted to ~ove ~dlrectlonally, normal to the novement of the prlnt medlum through the prlnter. The 3~
1;~0~983 1 carrlage movement 18 controlled by a motor and an asso-clated be~t drlve, with the motor controlled by the mlcroprocessor.
Insertlon of an lnk-Jet cartrldge lnto the car-rla~e often necessltates use of two hands or two opera-tlons. Further, many cartrldge/carrla~e conflguratlons do not provlde slmultaneous allgnment of the no~zle plate ln the X, Y, and Z dlrections. Flnally, contact between the prlnthead and the lnterconnect means ~ust be rellably made, ln order to ensure proper nozzle flrlng.
Accordln~ly, lt i8 desired to provlde a car-trldge/carrlage assembly that lncludes the foregolng advanta~es without the llmltatlons of the prlor art.
DISCLOSURE OF ~NV~NTION
In aecordanee wlth the lnventlon, a prlnthead eartrld~e and carrla~e asse~bly 18 provlded eomprlslng:
20(aJ a carrlage;
(b) means for securln~ a prlntln~ cartridge ln posltlon in the carrlage; and (c) lntereonnect means for supplyln~ electrl-cal slgnals to the cartrldge, lncludln~ force loadlng means for urglng the lnterconnect means agalnst the cartrldge.
The cartrldge has top, bottom, sldos, front and rear surfaces and ineludes a prlnthead on the bottom surface, a contaet on the back surfaee eonneeted to the prlnthead, referenclng pads on the slde surfaees, and a llp on the bac~ surface for aeceptlng a snap sprlng for lockln~ the cartrld~e ln posltlon ln the earrlage. The seeurlng means lncludes the snap sprlng ~nd means for recelvln~ the referenclng pads on the eartrldge. The ~3(34983 force loading means urge the interconnect means against the contact of the cartridge.
The printhead cartridge/carriage assembly sf the invention requires only one hand of the operator to both insert and lock the cartridge in position. Further, the cartridge/carriage assembly provides simultaneous alignment of the nozzle plate in the X, Y, and Z
directions. Finally, contact between the printhead and the interconnect means is reliably made each time the cartridge is inserted and locked in position, thereby ensuring proper nozzle firing each time.
Other aspects of this invention are as follows:
A printhead carriage lock-in assembly for use with a cartridge in a printer, for printing on a print medium, comprising:
a. carriage means;
b. said carriage means including base support means for receiving the cartridge;
c. said base support means depending into referencing means, for aligning the cartridge in proper printing position along at least two directions;
d. said base support means further including retention means for causing the cartridge to be locked in position relative to said carriage means;
e. electrical interconnect means, for supplying control signals to the carriage;
f. the cartridge including a reference system corresponding to, and generally coordinating with, said referencing system of said base support means, for providing proper alignment to the cartridge during its positioning relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;
A
3 a ~ 04983 g. said referencing means including a pair of downwardly depending, spaced-apart, generally oppositely disposed L-shaped members, for engaging said reference system of the cartridge;
h. the cartridge including a rear ledge, and said retention means including spring means for engaging said rear ledge in order to retain the cartridge in a locked position;
i. the cartridge further including a top portion, a bottom portion, and printhead means generally secured to said bottom portion; and j. said reference system of the cartridge including two set of similar pads, generally disposed near said bottom portion in a substantially symmetrical relationship relative to said printhead means;
k. said reference pads abutting one of said L-shaped members:
1. said reference pads abutting the other L-shaped member; and m. the cartridge further including lock-out ear means, slightly protruding outwardly from said top portion, for enhancing the orientation of the cartridge inside said carriage means.
A printhead carriage lock-in assembly for receiving a cartridge having electrical contacts, a reference system and a plurality of print elements, the print elements being disposed out of the plane of the electrical contacts, the printhead carriage lock-in assembly comprising:
a. carriage means:
b. said carriage means including base support means for receiving the cartridge;
c. said base support means depending into referencing means, for aligning the cartridge into a proper printing position along at least two directions:
3b ~304983 d. said referencing means generally coordinating with the reference system of the cartridge, for providing proper alignment to the cartridge during its position relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;
e. electrical interconnect means, for supplying control signals to the cartridge electrical contacts;
and f. said electrical interconnect means being disposed out of the plane of the cartridge electrical contacts to avoid obstructing the firing path of the print elements onto a print medium, to minimize contamination of said electrical interconnect means resulting from the firing of the print elements, and to allow for a desirable relatively close spacing between the print elements and the print medium.
A printhead carriage lock-in assembly for use with a cartridge in a printer, for printing on a print medium, comprising:
a. carriage means;
b. said carriage means including base support means for receiving the cartridge;
c. said base support means depending into referencing means, for aligning the cartridge in proper printing position along at least two directions;
d. said base support means further including retention means for causing the cartridge to be locked in position relative to said carriage means;
e. electrical interconnect means, for supplying control signals to the carriage;
f. the cartridge including a reference system corresponding to, and generally coordinating with, said referencing system of said base support means, for providing proper alignment to the cartridge during its 3c positioning relative to said carriage means, and for causing the cartridge to be retained in position during the printing operation;
g. said referencing means including a pair of downwardly depending, spaced-apart, generally oppositely disposed L-shaped members, for engaging said reference system of the cartridge:
h. the cartridge including a rear ledge, and said retention means including spring means for engaging said rear ledge in order to retain the cartridge in a locked position;
i. said carriage means further including chute means secured to said base support means, for helping guide the cartridge in position; and said chute means including spring means for applying a relatively light force against the cartridge, to help guide its alignment and positioning inside said chute means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an assembled carriage/cartridge assembly, together with electrical interconnect thereto;
FIG. 2 is an exploded side elevational view showing the assembly of the electrical interconnect and an elastomeric support in the cartridge;
FIG. 3 is a perspective view, partly cut-away, of the elastomeric support;
FIG. 4 is a front elevational view of the carriage;
FIG. 5 is a side elevational view of the carriage, without the cartridge;
FIG. 6a is a cross-sectional view of the assembly depicted in FIG. 5, showing the cartridge inserted into the carriage, but not locked into place;
FIG. 6b is a view similar to that of FIG. 6a, but showing the cartridge locked in position;
FIG. 7 is a view similar to that of FIG. 6b, but showing a greatly enlarged view of the electrical in-i304983 1 terconnect and elastomeric support asse~bled ln the carria~e;
FIG. 8 18 a slde elevatlonal vlew slmllar to that Or FIG. ~, ~lth th~ cartrld~e chute removed ln order to show the positlonln~ of the electrlcal lnter-connect ln the carrlage; and FIG. 9 18 a perspectlve vlew of the cartrldge, showln~ the prlnthead electrlcal contact, whlch pro-vldes electrlcal connectlon to the reslstors in the prlnthead, and the reference pads.
BEST MODES OF CARRYING OUT THE INV~NTION
Rcferrln~ now to the drawln~s whereln llke numer-als of reference designate llke elements throu~hout, a prlnt cartrld~e/carrla~e assembly, denoted genorally at 10, 18 shown ln FI~. 1. The assembly 10 comprlses a carrla~e 12 ln whlch a prlnt cartrld~e 1~ 18 deplcted, locked lnto posltlon. An lnterconnect strlp 16 pro-vldes electrlcal sl~nals from a ~lcroprocessor (notshown) to the carSridge 14, as dlscussed ~ore fully below.
As shown ln FIG. 2, the carrla~e 12 conprlses a base support ~B and a chute 20 affixed thereto by fa~-t~nlng ~eans 22. The carrla~e 12 advanta~eously com-prlses a ~lass-fllled, carbon-fllled, polytetrafluoro-ethylene-fllled, slllcon-fllled polycarbonate.
The lnterconnect strip 16 and a spring pad 2~ are sandwlched by the support 18 and chute 20. The sprln~
pad 2~ co~prlses a reslllent, elastonerlc naterlal and, a8 seen ln FI~. 3, comprlses a plurallty of reslllent bumps 26. ~he sprln~ pad 24 18 seated ln a depresslon (shown ln FIG. 4) ln the carrla~e base support 1~, i~O4983 1 behlnd a portlon of the lnterconnect strlp 16, as de-scrlbed more ~ully below.
The base support 18 and chute 20 are all~ned ln proper relatlon~hlp by ~old-d-ln ~oatur-o uch ~c ~lp~
27, whlch en~a~e throu~h correspondin~ open~n~s ln the lnterconnect strlp 16 lnto opposed openln~s in the other member.
~ he lnterconnect strlp 16 comprlses a ~trip of flexible dlelectrlc materlal, carryln~ a plurality of electrlcally conductln~ llnes 28, as seen ~ore clearly ln FIG. 8. The conductln~ llnes 28 ter~lnate ln conv~x contact bu~ps or dlmples 30, whlch are conrlgured ln a partlcular pattern.
The bumps 26 on the sprlng pad 2~ are confl~ured 1~ ln the same pattern as the contact dlmples 30 on the interconnect strlp 16. As seen ln FIG. 7, the sprln~
pad bumps 26 provlde a force loadln~ means against the contact dlmples 30 to ur~e them a~alnst the cartrldge 14.
The cartrld~e 14 comprlses top 32, bottom 34, sldes 36, 38, front ~0 and back ~2 surfaces. The car-tridge 14 advantageously comprlses a ~odlfled poly-phenylene oxlde.
A prlnthead ~4 18 provlded on the bottom surface 2S 3~. The prlnthead ~ comprlses a plurallty of resls-tors (not shown) assoclated wlth a plurallty of nozzles (not shown) formed ln a nozzle plate (not shown). Ink (not shown) 18 stored ln a reservolr lnterlor the car-trld~e l~. .
The cartrld~e 14 also lncludes a contact ~trlp ~6 on the back surface ~2, ~hlch wraps around to the bot-tom surface 3~ to provlde a plurallty Or conductlng paths or traces to the reslstors. In partlcular, each re~lstor 18 supplled by an electrical slgnal alon~ a ~304983 1 unlque conductln~ path. The contact strip ~6 lncludes a plural~ty of concave contact pads ~8, which are ar-ranged ln the same pattern as the eonvex eontact dlm-ples 30 on the lntereonn-et tr~p 1~. ~oekln~ o2 the eartrldge 1~ ln the earrla~e 12, a8 de~cr~bed ln ~reat-er detall below, ~atehes up the eontact dlmples 30 wlth the contact pads ~8, to provide an eleetrleal path from the mlcroproeessor to each of the reslstor ln the prlnthead 44.
The eontact strlp 46 comprlses a flexlble materlal havlng a plurallty of eleetrleal traces thereon. Pre-ferably, a tape automated bond (TAB) elreult of the type manufactured and sold by 3M Company (Mlnneapolls, MN) is employed.
The top surface 32 of the cartrldge 14 19 provlded wlth a palr of flnger grlps 50a, 50b. The larger fln-ger grlp 50a termlnates ln a V-shaped member 52a, whlch may be provlded wlth an arrowhead lnslgnla to denote the proper dlreetlon of orlentation of the cartrldge 14. When the cartrldge 14 18 loeked ln the earrlage 12, the eartrldge 18 recelved by a slmllarly shaped surface on the earriage to provlde a visual referenee for proper orlentatlon. Loek-out ears 54 further aet to prevent ~ls-orlentatlon of the eartrld~e 14 ln the earrlage 12.
Xeference pads 56, seen more clearly ln FIG. 9, are provlded on the cartrldge 14 near the base thereof.
In partlcular, two sets of referenee pads 56 are pro-vided; these comprlse sculpted surfaces that allgn the nozzle plate ln the X, Y and Z dlrectlons. ~he X ref-erenee pad 56x ls a surfaee parallel to the slde sur-~ace 38. (There $8 only one X referenee pad 66x, slnee the earrlage 12 18 provlded wlth a slde sprlng 58 whlch ur~es against the opposlte slde surfaee 36 to foree the 1 cartridge a~ainst one slde of the chute 20. ~he Y
reference pad co~prlses the upper vertlcal surface 56y of the sculpted surface. The Z reference pad comprlses the lnner horlzont~l ~urfac- ~6z o~ the oculpted ~ur-face. The Junctlon of S6y and 56z comprlses~a plvot or rotatlon p~lnt 66r, about which the cartrld~e 14 ro-tates durin~ the lock-ln operation.
Downwardly dependin~ L-shaped ~e~bers 60a,b on the support ba~e 18 each cooperatlvely en~a~e one of the reference pads 56 ln ~atln~ association. A snap-sprlng 62 ln the upper portlon of the chute 20 en~a~es a led~e ~ember 6~ on the back surface ~2 of the cartrid~e 14.
The L-shaped ~embers 60a,b provlde reference sur-face a~ainst whlch the reference pads S6 of the car-trld~e bear. ~n partlcular, reference pad 56x bearsa~ainst reference surface 60x on member 60a (the me~ber on the opposlte side of the slde sprln~ 58). Reference pads 56y push back a~alnst reference surfaces 60y (shown ln FIG. 2J. Reference pads 56z bear down on reference surfaces 60z.
The snap-sprlng 62 18 housed ln a ~olded-ln fea-ture 66 of the carrla~c support base 18. A ~atln~
housln~ 6~, whlch slts abova the snap-sprln~ 62 when the base 18 and chute 20 are assembled, lncludes an 2S lnward V-shaped surface 67a, whlch recelves the slmi-larly-shaped surface 52a of the cartrld~e 1~. The rear of the housln~ 66 co~prlses a fln~er ~rlp 68. The front of the cartrld~e chute 20 18 al80 provlded wlth a fln~er ~rip 20b.
The support 18 of the carrla~e 12 lncludes a bear-in~ ~0, which 18 assoclated wlth a carrlago rod (not shown). The carrla~e rod 18 posltloned substantlally parallel with the paper drlve axls (not shown), and per~its bldirectlonal ~ovement of the carrla~e 12 1 therealong. The carrlage 12 ls noved by a belt (not shown), attached to the carrlage by a belt attachment ~2. The belt ~8 attached to a carria~e drlve motor (not shown), whlch 1- controll-d by th- ~cro~roce~sor.
A reference means, or sllder bump, ~ rldes on the surface of a carrla~e gulde ~6. The wel~ht of the carrlage 12 preloads the sllder bump ~4 a~alnst the carrla~e gulde 76, thereby ~aking constant contact.
The sllder bump ~4 comprlses a low-rrlction, lon~ wear-ln~ materlal and ~ay be a separate plece or a ~olded-ln feature of the carrla~e 12. The sllder bump ~4 serves to nalntaln the prlnthead ~4 a constant, ~lxed dlstance from the prlnt medlum.
The carrlage base 1~ also lncludes an lnterposer ar~ 78 secured ln a tube 80. The function of the lnterposer ar~ 18 related to ~echanlcally trl~erln~
certa~n features ln the servlce statlon where the as-sembly 10 resldes ln between prlntin~ operatlons, and 18 not relevant to the inventlon hereln.
The prlnthead lock-ln mechanlsm 18 consldered unlgue, slnce lt sl~ultaneously all~ns the nozzle plate ln the X, Y, and Z dlrectlons and all~ns, wlpes, and loads the contact pads of the electrlcal lnterconnect strlp 16. Thl~ 18 accompllshed wlth no addltlonal 2S ball, latch or lever arm, as seen on other lnk-~et prlnters. The allgnment of the nozzle plate and the loadln~ of the lnterconnect strlp 16 occurs when the user rotates the cartrldge 1~ ln the dlrectlon of the arrow 82 (FIG. 6a), about the plvot polnt 56r. The SO user does thls by squeezln~ the cartrld~e thumbhold 50a and the carrla~e fln~er hold 68 between the thumb and forefln~er.
Before the user can squecze the cartrld~e 1~ lnto lts locked-ln posltlon, the user ~ust be able to easlly 13049~3 1 drop the cartrld~e into the carrla~e chute 20. The sprin~s 58, 62 whlch ali~n the cartrid~e 1- do not apply any force to the cartrld~e untll the cartrldge be~lns to rotate ~nto th- lock-d-~n po-lt~on ~-ho~n ln ~IG. 6b). Thls leaves an unobstructed path for the user to easlly drop tbe cartrldge 14 lnto the pre-rota-tlon positlon, deplcted ln FIG. 6a. However, the slde-klcker sprlng 58 applles llght force when ~nsertlng the cartridge 14.
The cartrld~e 14 rotates about the reference pads 56, speciflcally, polnt 56r. ~3 the user rotates the cartrldge 1~, the align~ent functlons are performed before the electrical lnterconnect strlp 16 18 loaded.
Flrst, one slde 36 of the cartrl~ge 1~ en~a~es the lS molded-ln carrlage slde sprlng 58. Thls ~prlng 58 references the cartrldge 1~ ln the X dlrectlon by push-lng the cartrldge sldeways untll the X roference pad 56x 18 touchlng the X re~erence pad 60x on the car-trld~e. The result 18 an accuratc, no 810p allgnment of the nozzle plate ln the X dlrectlon.
The next action to occur 18 the all~nment ln the Z
dlrectlon. ~8 the rear ledge 64 of the cartrldge 1~
encounters the rear metal snap-sprlng 62, the sprlng pushes the cartrld~e ln the Z dlrectlon untll the Z
reference pads 56z are ln contact wlth the Z reference pad~ 60z on the carrla~e 12. ~he result i8 an accu-rate, no 810p reglstratlon of both the electrlcal ln-terconnect 16 and the nozzle plate ln the Z dlrectlon.
As the cartrldge 1~ contlnues to rotate about the rotatlon polnt 56r lnto posltion, the electrlcal lnter-connect concave contact pads ~8 on the cartrld~e con-tact ~6 get wlped sllghtly by the convex contact dlm-ples 30 on the carrlage lnterconnect strlp ~6. ~hls offers l~proved rellablllty over the dlmpled lntercon-1;304983 1 nect on prior art prlnters, because the oxides andcontamination are wlped off the contacts 30 and ~B
before the lnterconnect 16 18 loaded.
~he w1pln~ action 18 followed by the alignment of the cartrld~e electr1cal contact pads 48 ln the X dl-rection. This occurs when the cartrld~e'~ outer rear heel lock tabs ~4a,c en~a~e the sides 86a,c of the heel lock slot 86 on the carrla~e 12. The lnterconnect strlp 16 on the carrla~e 12 18 referenced accurately to the heel lock slot 86 by plns 2~, thereby providing the requlred sllgnment of the lnterconnect strlp to the cartrld~e' 8 electrical contact pads ~8. The contact strlp ~6 18 fastened, ~uch as by ~lue or adheslve, to the cartrld~e 14 and 18 referenced by an asse~bly ma-chlne.
Flnally, the cartrld~e 14 18 all~ned accurately lnthe Y dlrectlon. ~he clectrlcal lnterconnect' 8 rubber ~prlng pad 24 on the carrla~e 12 ~ust be deflected the proper dlstance ln the Y dlrectlon ln order to maintaln the requlred contact force. In the back ~2 of the cartridge 1~, the rubber sprln~ 2~ pushes back a~alnst the electrlcal contacts 30 and ~8 80 that the Y refer-ence pads 56y on the cartrld~e contact the Y reference pads 60y on the carrla~e. ~hls malntalns the necessary force on the contact pads ~8 located on the contact strlp ~6, on the rear surface ~2 of the cartr~d~e 1~.
This al80 provldes an accurate Y re~istratlon of the nozzle plate as well a~ controllln~ the rotational allgnment of the nozzl~s.
At the top 32 of the cartrld~e 1~, the requlred contact force in the Y and Z dlrectlons 1~ ~alntalned by the rear snap-sprln~ 62. As the cartrid~c 1~ ro-tates lnto tho lock~d-ln posltlon, the rear llp 6~ of the cartrid~e 1~ deflects the r~ar sprln~-snap 62 and 13049~33 1 passe~ over an over-center polnt 62a (FI~. 6a) on the ~nap-sprlng. The snap-sprln~ 62 ls dcslgned to apply ~bout ~0% of lts force in the Y dlrectlon. Thl6 18 the force requlr~d to ~alnt~ln th~ ctrlcal lnt-rconnect 16 ~n the rear ~2 o~ the cartrld~e 1~.
As the cartrldge 14 passes the over-center po~nt 62a on the rear snap-sprln~ 62, the cartrid~e ~akes an audlble "snap", s~nallin~ to the user that the car-trld~e is ln the proper locked-in poslt1On. The force of the rubber interconnect sprln~ pad 24 18 adequate to hold the cartrld~e into lts accurately all~ned positlon under the lar~e acceleratlons and shock loads the car-trld~e encounters ln nor~al println~ operatlons.
To remove the cartrld~e 1~ ~rom the carria~e 12, the user slmply rotates the cartrld~e by sgueezln~ the cartrldge fln~er hold 50b and the carrlage thumb hold 20b between the thumb and forefln~er. The rear led~e 64 on the carrlage 14 deflects the rear snap-sprlng 62 untll the cartrld~e over-centers lnto the unlocked pos1tlon. There 18 an audlblc "snap~ whlch tells the user that the cartrld~e 1~ can now be 11fted out o2 the carrlage 12 for d~sposal.
INDUSTRIAL APP~ICABILITY
The prlnt cartrld~e/carrla~e assembly d1sclosed herein 18 sultably employed ln lnk-Jet prlnters, partl-cularly thermal lnk-Jet prlnters.
Thus, there has been dlsclosed an lnk-~et prlnt cartrldge/carrla~e assembly whlch 18 eas11y assembled and disassembled, wlth reproduclbly accurate re~lstra-tlon of the cartrld~e in the carrla~e. Varlous chan~es and ~odlflcatlons o~ an obvlous nature wlll be readlly apparent to those of ordinary sklll ln this art, and all such chan~es and ~odifications are considered to fall wlthin the scope of the lnventlon, ~8 deflned by the appended clalmo.