LIQUID SUPPLY UNIT BACISGROUND [0001] The present invention relates to a liquid supply unit. [0002] An inlr cartridge (also simply called "cartridge") configured to supply ink to a printer as an exa~upleo f a liquid ejection device has been lcnown conventionally as a liquid supply unit configured to supply a liquid to the licltud ejection device. A cartridge containing a pl~~raliotfy d ifferent color inks has been proposed to supply the respective color inks through , respective inlc supply ports to the printer as disclosed in Japanese Patent Publication (JP 2008-74090A). [0003] The technique proposed in JP 2008-74090A has tlie supply ports for the respective color inks sealed by a seal member to prevent leakage of ink in the cartridge attachment state. In the course of attachment or detachment of the cartridge, however, the inlc supply port is exposed, so that there is a possibility that inlc is leaked from the cartridge. In the cartridge attachment state, degradation of the seal menlber may cause leakage of ink. In the event of lealrage of one color inlc from its inlc supply port, the lealred inlr may be diffi~seda long the bottom wall sul-face of the cartridge and reach the periphery of tlie ink supply port for another color inlc. In the course of attachment or detachment of tlie cartridge, the anotller color ink may be ' contaminated with the lealced inlc reaching the periphery of the inlc supply port for the anotlier color ink. This may lead to color mixing of the supplied inlr. Tlle cartridge has contacts or terminals for receiving and sending electric signals. There is also a need to prevent the contacts or the terminals from being exposed to the lealred inlr. There is accordingly a need to more effectively suppress.diffilsion of the lealred inlr. I11 a liquid supply unit configured to contain and supply a liq~iida, liquid ejection device configured to receive supply of a liquid &om the liquid supply unit and a system including the liquid supply unit and the liquid ejection device, there are other needs including downsizing, cost reduction, resource saving, easy manufacture and improvelnent of usability. [0004] In order to solve at least part of the problems described above, the invention may be implemented by an aspect described below. [0006] (1) Accorcting to one aspect of the invention, there is provided a liqnid supply unit configured to supply a liquid. The l i q ~ ~siudp ply unit is mountable on a liquid st~pplyu nit mounting structure having a first liquid introducing part, a second liquid introducing part, a third liquid introducing part and a projection which is located between the first liquid introducing part and the second liquid introd~~cinpgar t and is located from between the first liquid introdt~cingp art and the second liquid introducing part to the third liquid introdncing part. The l i q ~ ~siudp ply unit comprises: a first liquid supply port configured to be connectable wit11 tlie &st liquid introducing part such as to supply a first liquid to tlie first liquid introducing part; a second liquid supply port configured to be connectable with the second liquid introducing part such as to supply a second liquid to the second liquid introducing- part; a third liquid supply port configured to be connectable with the third liquid introducing part such as to supply a third liquid to the third liquid introducing part; and a groove formed betkeen the first liquid supply port and the second liquid s~~ppployr t and extended from between the first liquid supply port and the second liquid supply port toward the third liquid supply port, such as to allo\v the projection to be inserted therein. In the liquid supply unit of tlus aspect, in the event of leakage of the third liquid from the third liquid supply port, this configuration enables the lealred third liquid to be guided to the groove which is extended toward the third liquid supply port and to be kept in the groove. The liquid supply unit of this aspect accordingly suppresses diff~~siofn t he lealred third liquid and prevents contamination of the lealred liquids. The liquid supply unit of this aspect suppresses diffi~siono f the lealred third liquid by the simple structure of the groove extended fro111 between the first liquid sul~plyp ort and the second liquid supply port toward the third liquid supply port. [00061 (2) The liquid supply unit of the above aspect may further con111rise: a first wall configured to have tlie h s t liquid supply port, the second liquid supply port, tlie third liquid supply port and the groove; a second mall opposed to the h s t wall; a third wall arranged to intersect with the first wall and the second wall; a fourth \vall arranged to intersect with the &st wall and tlie second wall and opposed to the third wall; a fifth wall arranged to intersect with the first wall and the second wall; and a sixth wall arranged to intersect with the fwst wall and the second wall and opposed to the fifth wall. In a plan view of the liquid supply unit in a direction from the first wall toward the second wall, the first liquid supply port may be located betwcen the fifth wall and the sixth wall, the second liquid supply port may be locatcd between the first liquid supply port and the sixth wall, the groove may be extended from the fourth wall toward the third wall, and the third liquid supply port may be locatcd betwcen the groove and the third wall. Tliis configuration enables the lealzed third liquid to be guided to the groove mhich is fortlied in the first wall and is extended toward tllc third liquid supply port and to be kept in the groove. The liquid supply unit of this aspect suppresses diffusion of the lealzed third liquid along the \vall surface of the first wall and prevents contamination of the lealzed liquids. In the liquid supply unit of tlus aspect, the groove is formed between the &st liquid supply port locatcd between the fifth wall and the sixth wall and the second liquid supply port located between the first liquid supply port and the sixth wall and is extended fiom the fourth wall toward the third wall. This configuration also enables the first liquid lealred horn the first liquid supply port or the second liquid lealzed fiom the second liquid supply port to be kept in the groove, thus s~~ppressindgif fi~siono f the lealced first liquid 6r the leaked second liqi~ida nd preventing contamination by the lealzed first liquid or the lealred second liquid. The liquid supply unit of this aspect suppresses diffusion of any of the lealzed liquids by tlie simple structure of the groove formed between the first liquid supply port which is located between the fiitll wall and the sixth wall and the second liquid supply port which is located between the &st liquid supply port and the sixtll ~valal nd extended from the fourth wall toward the third mall. [0007] (3) The Liquid supply unit of the above aspect may further comprise: a contact located on an outer wall surface of tlm third \Val1 and arranged to be electrically connectable with an electrode on the liquid supply unit niounting structure. In the plan view of the liquid supply unit in the dixection 'om tlie first wall toward the second wall, the third liquid supply port may be located betwcen the groove and the contact. This configuration keeps tlie lealzed third liquid in the groove and suppresses diffilsion of tlle lealced t k dl i q ~ ~aildon g the wall s~rfaceof the first wall toward the contact, t11~1s reducing the lilceliliood that tlie contact is exposed to the lcalzed tlurd liquid. [0008] (4) The liquid supply unit of the above aspect may further comprise: a first partition wall arranged to intersect wit11 the first wall and the second wall and located between the fifth wall and the sixth wall; a second partition wall arranged to intersect with the first wall, the second wall and the first partition wall and located between the fourth wall and thc third wall; a first liquid chamber defined by at least the first wall, the second wall, the fourth wall, the fifth wall, the first partition wall and the second paptition wall and arranged to comulunicate with the first liquid s~~ppployr t; a second liquid chamber defined by at least the first wall, the second wall, the fourth wall, the sixth wall, the first partition wall and the second partition wall and arranged to co~n~nunicawteit h the second liq~~isdu'p ply port; and a third liquid chamber defined by at least the first wall, the second wall, the third wall, the sixth wall and the first partition wall and arranged to com~n~~nicwaitteh the third liquid supply port. In the plan view of the liquid supply unit in the direction from the first wall toward the second wall, ' the groove may be located between the fourth wall and the third liquid chamber. This configuration lceeps the lealced third liquid in the groove so as to suppress diffusion of the lealced t1ll.d liquid along the wall surface of the first wall and prevent contamination of the lcalced liquids, and additionally causes the liquids contained in the first to the tlurd liquid chambers to be introduced to the Grst to the third liqnid introdtlcing parts of tbe liquid supply unit mounting structure. [0009] (5) In the liquid supply unit of the above aspect, the groove may be formed as a concave in the first partition wall. This configuration enables the groove to be readily formed without red~lcingth e capacities of the first liquid chamber and the second liquid chamber for containing the respective liquids. [0010] (6) In the liquid st~pplyu nit of the above aspect, in the plan view of the liqtlid supply nit in the direction from the first wall toward the second wall, the groove may be located between the fourth wall and a specific area where the first wall is in contact with a third seal element formed around a periphery of the third Iicluid introducing part of the Iiquid supply unit lnounting structure. This simple configuration enhances the effectiveness of lceeping the lealred third l i q ~ ~iind t he groove and thereby s~~ppressing diffusion of the leaked third liquid along the wall surface of the first wall and the effectiveness of preventing contamination by the lealrcd third liquict. [0011] (7) In the liquid supply unit of the above aspect, the fourth wall nlay have a concave arranged to be continuous with the groove. This configuration has the following- advantageous effects. The liquid supply unit is generally inclined and approacl~esd o example, a foamed material such as polyurethane foam or a fibrous material of bundled polypropylene fibers. The supply port-side liquid retaining member 406 and the liquid retaining member 460 have different characteristics of retaining the Iiq~ud. The supply port-side liquid retaining member 406 is made to have a lliglier pore density or density of pores than the Liquid retaining member 460. According to the magnitude relationship of the pore density, the supply port-side liquid retaining member 406 11;s greater capillary force than the capillary force of the liquid retaining member 460. [0058] This magnitude relationship of the capillarity force bet\veen the supply port-side Liquid retaining member 406 and the lirpid retaining member 460 causes ink contained in the liquid retaining member 460 to flow in the sequence described below. Ink flows from a member having s~nallcr capillary force to a member having greater capillary force. As shown in Fig. 6, when ink contained in the s~~ppployr t-side liquid retaining member 406 is suclred via the liquid introducing base 703 to be consumed, inlr contained in the liquid retaining nlelnber 460 laid on the upper surface of the supply port-side liquid retaining meniber 406 moves to the supply port-side liquid retaining melnber 406. The [hiving force of such inlr migration is mainly given by the capillary force of the supply port-side liqnid retaining member 406. Snch inlr migration has no difficulty, due to the air co~nmunication through the air communication hole 434 via the through hole 402a and the air groove 403 continuous with the th~ougho le 402a formed corresponding to the location where the liquid retaining menlber 460 is placed. [00591 Placing the supply port-side liquid retaining meniber 406 and the liquid retaining member 460 having different characteristics in the recess 421 of the casing 420 as described above, in combination with using the metal mesh 703s having greater capillary force than the capillarity force of the supply port-side liquid retaining n~emhe4r 06 for the liq~udin troducing base 703, allows for efficient consunlption of ink contained in the liquid retaining member 460. In other words, this reduces the remaining qnantity of rmused inlr in the liquid retaining member 460. [0060] As long as the capillary forces of the supply port-side liquid retaining member 406 and the liquid retaining member 460 are arranged to decrease with an increase in distance from the liquid introducing base 703, the magnitnde relationship of the pore density between the respective liquid retaining members 406 and 460 is not limited to the configuration of this embodiment. For example, when the supply port-side liquid retaining member 406 and the liquid retaining meniber 460 have identical pore densities, the respective liquid retaining nie~~ibe4r0s6 and 460 niay be subjected to water repellent treatment or hydrophobic treatment to have the magnitude relationslGp of the capillary force described above. [0061] The cartridge 4 also has a groove 450 fornled on the bottom surface of the bottom wall 422 with the liquid s1111ply port 407 (outer wall surface on the -Z direction side) as shown in Figs. 9 and 10. This groove 450 is extended from the second end wall 42.1-side toward the liquid supply port 407 to reach the peripllery of the periplicral concaved area 407b withont interfering with the recess 421 as shown in Fig. 11. In the plan view of tlie cartridge 4 in a direction from tlie bottom wall toward the cover 401 (+Z direction), the liqnid supply port 407 is located between the groove 450 and the circuit substrate 410 as sl~oowni n Figs. 9 and 10. Thc width of Lhe groove 450 in the X-axis direction on the bottom wall 422 is set to bc narrower than the width of the peripheral concavcd area 407b in the X-axis direction. Accumulation of ink in the groove 450 limits the ink diffusion area. The narrower width of the groove 450 effectively leads to the snlaller diffusion area. Tlie groove 450 nlay be formed to be continuous with tlie peripheral concaved area 407b. This configuration enables inlr to be introduced into the groove 450 without lealrage to outside of the peripheral concaved area 407b. [00621 Tlie cartridge 4 also has a pair of engagement projections 424t at a lower edge of the outer wall surface of the second end wall 424. In tlie course of atlach~nenot f the cartridge 4 lo the cartridge attachment structure 7, the engagement projections 424t enter the end wall 730 of the cartridge atlacllment structure 7 (Fig. 4) and are involved in positioning of the cartridge 4. Lo0631 A-4. Structure of Cartridge 5 The cartridge 5 has the different structure &om that of the carlridge 4 by containing t h e e different color inks, yellow, magenta and cyan. In tlie description of the s t r a c t ~ ~orfe t lie cartridge 5, the like components to those of the cartridge 4 are expressed by lilre numerical sy~nbolsw ill1 the digit at a liigllest place changed to 5 and are only briefly explained. Fig. 12 is an appearance perspective view illustrating the cartridge 5. Fig. 13 is an exploded perspective view illuslrating tlie cartridge 5. Fig. 14 is an appearance perspective view illustrating the carlridge 5 viewed from the bottom side. Fig. 15 is an appearance perspective view illustrating the carlridge 5 without the circuit substrate 510 viewed from the bottom side. Fig. 16 is a schematic cross sectional end view illustrating a casing 520, taken on a line 16-16 in Fig. 12. Fig. 17 is a schematic cross sectional end view illustrating the casing 520, talren on a line 17-17 in Fig. 13. In the illustration of Fig. 17, a recess 521y described later is shown to be located on the front side of Lhe sheet surface in tlie cross section of the casing 520 talren on the line 17-17 in Pig. 13. [0064] As illustrated in Fig. 13, the cartridge 5 has the casing 520, the cover 501 and the circuit substrate 510. The cover 501 is fixed to the casing 520 to cover three recesses 521m, 521c and 521y of the casing 520 (Fig. 13). The casing 520 has a partition wall 571 located between a first side wall 525 and a second side wall 526, a partition wall 572 located between the partition wall 571 and a second end wall 52.1 and a partition wall 573 located between the partition wall 571 and a first end wall 523. These partition walls 571, 572 and 573 form the recesses 521111, 521c and 521y corresponding to the respective color inlrs, magenta, cyan and yellow. The cartridge 5 has supply port-side liquid retaining members 506 placed in respective areas defined by semicircc~lapr rojections 527 provided on the respective peripheries of ink supply ports 507111, 507y and 507c formed in a bottom wall 522 in the respective recesses 521m, 521c and 521y, and also has liquid retaining members 560 placed on the supply port-side liquid retaining lnembers 506. [0065] The partition walls 571, 572 and 573 and the recesses 521m 521c and 521y have the following positional relationship in the state that the cover 501 is joined with the casing 520. The partition wall 571 is located to intersect with the bottom wall 522, the cover 501, the first side wall 525 and the second side wall 526 andto be opposed to the first end wall 523 and the second end wall 524. The partition wall 572 is located to intersect with the bottoni wall 522, the cover 501, the first end wall 524 and the partition wall 571 and to be opposed to the first side wall 525 and the second side wall 526. The recess 521m communicating with the ink supply port 507m is defined by the bottom mall 522, the cover 501, the second end xvall524, the &st side wall 525, the partition wall 571 and the partition wall 572. The recess 521c communicating with the ink supply port 507c is defined by the bottom wall 522, the cover 501, the second end wall 524, the second side wall 526, the partition wall 571 and the partition wall 572. The recess 521y coinmunicating with the ink supply port 507y is defined by the bottom wall 522, the cover 501, tbe first end wall 523, the sccond side wall 526, the partition wall 571 and the partition wall 573. In one modification, the partition wall 573 may be omitted. In this nlodified application, the recess 521y is defined by the bottom wall 522, the cover 501, the f i s t end wall 523 the first side wall 525, the second side wall 526 and thepartition wall 571. [oOGG] As illustrated in Figs. 14 and 15, the bottom wall 522, the first end wall 523, the second end wall 524, the first side wall 525 and the second side wall 526 of the casing 520 have the similar structures to those of the corresponding walls of tlie cartridge 4. The cartridge 5 lias thc circuit substrate 510 located on tlie first end wall 523-side of the casing 520. As in the structure of the cartridge 4, the circuit substrate 510 is fixed to a substrate mounting structure 511. The circuit snbstrate 510 lias terminals 512 having substantially the similar structure to that of the cartridge 4. Contacts of the respective terniinals 512 are electrically connected with electrodes of thc electrode asse~ubly8 10 provided on tlie carriage 8 when the cartridge 5 is attached to the carriage 8 as described above. The substrate mounting structure 511 has tlie similar structure to that of the cartridge 4. The circuit substrate 510 is fixed to the substrate mounting structure 511 by thermally caulking projections 514 protruded fro111 tlie substrate mounting structure 511. [00G7] As illustrated in Figs. 12 and 13, the cover 501 has a cover member 530 and an outward extension member 531. The cover member 530 is in a flat plate-lilre shape and is arranged to cover the recesses 521m, 521c and 521y of the casing 520. The o u t ~ v a ~exdt ension member 531 is extended outward from the cover member 530 on the first end mall 523-side where tlic circuit s~~bstra5t1e0 with the terminals 512 is located, and includes a bent extension scction 532 and an inclincd extension section 533. Tlie structure of these extension sections 532 and 533 is similar to the structure of the cartridge 4. Tlie bent extension section 532 is bent at al~proximately9 0 degrees to the cover member 530 and is extended to be protruded along a first direction from the cover 501 toward the casing 520 (-Z . direction in Fig. 13). The inclined extension section 533 continuous with the bent extension section 532 is extended to a location to hang over the terxninals 512 of the circuit substrate 510 in the plan view of the covcr 501 in the &st direction fiom the cover 501 toward the casing 520 (-Z direction in ~ i13)~. In. th e state that the cover 501 is fixed to the casing 520, the outward extension member 531 is hung over an opening 513 of the substrate mounting structtwe 511 to close the opening 513'on tlie upper edge side of the fist end wall 523 as shown in Pig. 15. In the state that the cover 501 is fixed to the casing 520, the out~vard extension member 531 is engaged with an engagement element 505 as shown in Fig. 12. The outward extension member 531 is protruded to the outer side of at least the terminals 512 in the lower line of the circuit substrate 510 in a second direction from the second end wall 524 toward the first end wall 523 (+Y direction in Figs. G and 13). In one modification, the inclined exlcnsion section 533 may be extended longer to be protruded to the outer side of all the terminals 512 of the circuit substrate 510. [0068] As illustrated in Fig. 13, the cover 501 has through holes 502a, 502b and 502c, an air groove 503 arranged bctxveen the through hole 502a and the through hole 502c and an air conlmunication hole 534 provided for each of the recesses 521m 52c and 521y corresponding to the respective color inlrs, magenta, cyan and yellow, and seal member receiving elemelits 537 formed at respective corners of the cover 501. The seal member receiving elements 537 are protruded from the upper surface of the cover 501 to substantially the same height as thc height of t11e circumferential walls of the through holes 502a, 502b and 502c and the circumferential walls of the air grooves 503 and serve as joint seat elements of the seal member 504. [O0691 The three air colnillunication holes 534 are aligned in the X-axis direction in the outer periphery of the cover member 530 and arc formed to pass through the cover 501. The through hole 502b provided for each of the color inlrs, yellolv, magenta and cyan is formed to pass through the cover 501 ant1 is arranged to be aligned in the Y-axis direction with corresponcling one of the air communication holes 534 aligned in the X-axis direction. The air colnmunication hole 534 and the corresponding tlwo~~ghohl e 502b aligned in the Y-axis direction are connected with each other by an air groove (not shown) on the rear surface of the cover 501. This air groove, the cover baclrside opening of thc througli hole 502b and the cover backside opening of tlie air communication hole 534 are sealed by a cover backside seal member 536. The recesses 521111, 521c and 521y of the casing 520 closecl by the cover 501 are accordmgly open to the air throng11 the respective air collllnunication holes 534 via the through holes 502a, the air grooves 503 and the through holes 502b. The tlwoug11 holes 502a, 502b and 502c and the air grooves 503 are sealed on the upper surface side of the cover 501 by the seal member 504. This arrangement of open to the air described above enables ink contained in the porous liquid retaining member 560 placed in the recess 521111, 521c or 521y for each color inlr in the casing 520 closed by the cover 501 to be supplied to the supply port-side liquid retaining member 506 and then to the liquid introducing part 710111, tlie l i q ~ ~iindtr oducing part 710c or the liquid introducing part 710y (Fig. 4) of the carriage 8 via the corresponding inlr supply port 507m, 507c or 507y. In other words, the corresponding color inlrs are respectively supplied through the inlr supply port 507111 of the recess 521111 to the liquid introducing part 710x11 of the carriage 8, tlwough the inlr supply port 507c of tllc recess 521c to the liquid introducing part 710c and througli the ink supply port 507y of the recess 521y to the liquid introducing part 710y. The respective inlr supply ports 507111, 507c and 507y have the following positional relationship. [0070] In the plan view of the casing 520 or the cartridge 5 in a direction from the bottoni wall 522 with the ink supply ports 507111, 507c and 507y toward tlie cover 501 (+Z direction), the inlr supply port 507111 is located betmeen the first side wall 525 and the second side wall 526. The ink supply port 507c is located between the inlr supply port 507m and the second side wall 526. [0071] As shown in Figs. 14 to 17, the cartridge 5 also has a first groove 580 and a second groove 581 on the bottom sturface of the bottoni wall 522 (outer wall surface on the -2 direction side) where the inlr supply ports 507111, 507c and 507y are formed. The first groove 580 is formed between the inlr supply port 507m corresponding to the liquid introducing part 710m for magenta and the ink supply port 507c corresponding to the liquid introducing part 710c for cyan (Fig. 4) and is extended ftom between the inlr sul~plyp ort 507m and tlle inlr supply port 507c toward tlie inlr sul~plyp ort 507y. The first groove 580 is formed in the partition wall 572 as a concave having such a depth that the guide projection 723 (Fig. 4) of the cartridge attachment structure 7 is inserted in the state of attacliment of the cartridge 5 to the cartridge attachment struct~n-e7 (Figs. 16 and 17) and is extended over the length of the partition wall 572, i.e., between the second end wall 524 and the partition wall 571. The first groove 580 and tlie ink supply port 507y has the following positional relationship described below. LO0721 As shown in Figs. 14, 15 and 17, tlie first groove 580 is extended from the second end wall 524 toward the first end wall 523. As shown in Figs. 13 to 15 and 17, the inlr supply port 507y is located between the first groove 580 and the first end wall 523. There are first to third positional relationships described below in the plan view of the casing 520 or the cartridge 5 in the direction from the bottom wall 522 toward the cover 501 (+Z direclion). In the first positional relationship, the inlr supply port 507y is located between the first groove 580 and lhe circuit substrate 510 as shown in Pig. 14. In the second positional rclationshil~,t he first groove 580 is located between the second end wall 524 and the recess 521y as shown in Fig. 17. In the third positional relationship, tlie &st groove 580 is located between the second end wall 524 and a peripheral concaved area 507b where the bottom wall 522 conies into contact will1 the elastic member 705 formed around the Liquid introducing part 710y (Fig. 4) of the carriage 8. Lilre the cartridge 4, tlie midth of the first groove 580 in the X-axis direction is set to be narrower than the width of the peripheral concaved area 507b. The h s t groove 580 may be formed to be continuous with the peripheral concaved area 507b. [0073] As illustrated in Fig. 17, the second groove 581 is formed in the second end wall 524 as a concave continuous with the first groove 580. The second groove 581 has a sliallo\ver depth in a direction from the bottom wall 522 toward the cover 501 than the depth of the first groove 580 in tlie clirection from the bottom wall 522 to\varcl the cover 501. Lo0741 A-5. Attachment of Cartridges Fig. 18 is a diagram scl~ematicallyil lu~stratinga ttachment of the cartridges 4 and 5 to tlie carriage 8. As illustrated, in tlie course of attachment, both the cartridges 4 and 5 are inclined such that the outer wall surfaces of the second end walls 424 and 524 face in the -Z direction when being inserted into the cartridge attachment structtwe 7 of the carriage 8. The engagement projections 424t and 524t of tlie respective cartridges 4 and 5 are subsequently inserted into the engagement holes 750 (Fig. 4) in the cartridge attachment structnre 7 of the carriage 8. The respective cartridges 4 and 5 are pressed in the -Z direction against the cartridge attachment structure 7 until the engagement elements 405 and 505 are engaged witli the cartridge engagement arnis 801 as shown in Fig. 6. [0075] As shown in Figs. 9 to 11, the cartridge 4 of this embodiment having the configuration described above has the liquid supply port 407 arranged to supply blaclr ink to the carriage 8 of the printer 10 or niore specifically to the liquid introducing part 710b of the cartridge attachment structure 7 (Figs. 4 and 6) of the carriage 8, and the circuit substrate 410 electrically connectable ~vithth e electrode assembly 810 of the car+age 8 in the printer 10. The liquid supply port 407 is located between the circuit substrate 410 and the groove 450 formed on the bottom surface of the bottom wall 422 to be extended from the second end wall 424. The configuration of the cartridge 4 of this embodiment has the following advantageous effects. The cartridge 4 is inclined in the course of attachment as shown in Fig. 18. The configuration without tlle groove 450 is lilrely to malre the flow of and diffilse tlle lealred inlr along the bottom surface of the bottom wall 422 in the event of leakage of blaclr inlr fiom the liquid supply port 407. The presence of the groove 450, howevel; causes the lealred inlr to be kept in the groove 450 of the bottom wall 422 (Fig. 11) and thereby suppresses diffusion of the inlr lealred from the liquid supply port 407. Additionally, the groove 450 guides the lealred inlr in a direction away from the first end wall 423 and accordingly reduces the lilrelihood that the terminals 412 are exposed to the lealred blaclr inlr. [00761 In the plan view of the casing 420 or the cartridge 4 in the direction from the bottom wall 422 toward the cover 401 (+Z direction), the cartridge 4 of the embodiment has the liquid supply port 407 located between the groove 450 and tlie circ~ustu bstrate 410 as shown in Figs. 9 and 10. This configuration of the cartridge 4 of the embodiment also lreeps black inlr lealred from the liquid supply port 407 in the groove 450 and suppresses diffusion of the blaclr inlr, t h ~r~edsu cing the lilrelihood that the terminals 412 are exposed to the lcalred blaclr ink. [0077] The cartridge 5 of the embodiment is attachable to thc carriage 8. The carriage 8 has the liquid introducing parts 710111, 710c and 710y and the guide projection 723 as shown in Fig. 4. The guide projection 723 is formed between the liq~liciln troch~cingp art 710111 and the liquid introducing part 710c and is extended from between the liquid introducing part 710m and the liquid introducing part 710c toward the liquid introducing part 710y. As shown in Figs. 13 to 15, the cartridge 5 of tlie embodiment has the inlr supply port 507111 provided to supply magenta ink to the liquid introducing part 710111, the inlr supply port 507c provided to supply cyan ink to the liquid introducing part 710c and the inlr s~lpplyp ort 507y provided to supply yellow inlr to the liquid introducing part 710y. The first groove 580 is formed between the inlc supply port 507m and the inlr supply port 507c. The h s t groove 580 is extended from between the inlr s~xpplyp ort 507111 and the inlr supply port 507c toward the inlr supply port 507y and is formed to allow for insertion of the guide projection 723. The cartridge 5 of the embodiment is inclined as shown in Fig. 18 in the course of attachment. In the event of lealrage of yellow inlr from the inlc supply port 507y, the lealred inlr is guided to the first groove 580 extended toward the inlr supply port 507y and is kept in the first groove 580. Accordingly the cartridge 5 of the cml~odiment suppresses diffusion of inlr leaked from the ink supply port 507y and prevents contamination by the lealred inlr. In the event of lealrage of ink from the ink supply port 507x11 or from the inlr s~~ppployr t 507c, the lealred ink is also kept in the first groove 580. This accordingly suppresses diffi~sionof the leaked inlr. The cartridge 5 of the embodiment can suppress diffi~siono f leaked ink by the silnple structure of the first groove 580 extended from between the inlr supply port 507111 and the ink supply port 507c toward the inlr supply port 507y. [0078] The cartridge 5 of the embodinlent has the bottom wall 522 \vith the inlr supply port 507111, the inlr supply port 507c, the inlr snpply port 507y and the first groove 580 formed therein, the cover 501 opposed to the bottom wall 522, the first end wall 523 arranged to intersect with the bottom wall 522 and the cover 501, the second elid wall 524 arranged to intersect with the bottom wall 522 and the cover 501 and opposed to the first end wall 523, the first side wall 525 arranged to intersect wit11 the bottom nlall522 and the cover 501, and the second side wall 526 arranged to intersect with the botto~u wall 522 and the cover 501 and opposed to the first side wall 525. As shown in Figs. 13 to 16, in the plan view of the cartridge 5 in the direction from the bottom wall 522 tomard the cover 501, the inlr supply port 507m is located between the first side wall 525 and the second side wall 526; the inlr supply port 507c is located between the ink supply port 507111 and the second side wall 526; the first groove 580 is extended i50111 the second end wa11.524 toward the first end wall 523; and the ink supply port 507y is located between the f i s t groove 580 and the first end wall 523. The cartridge 5 of this embodiment enables ink lealred from the inlr supply port 507y to be gnided to the first groove 580 extended tomard the inlr snpply port 507y on the bottom mall 522 and to be kept in the first groove 580. The cartridge 5 of this elnbodilucnt accordingly suppresses the inlc lealced from the ink supply port 507y from being diffused along the wall surface of the bottom wall 522 and prevents contamination by the leaked inlc. [0079] In the cartridge 5 of this embodiment, the first groove 580 is fonned between the ink supply port 507m which is located between the first side wall 525 and the second side wall 526 and the inlr supply port 507c which is located between the ink supply port 507111 and the second side wall 526 and is extended from the second end wall 524 toward the first end xvall 523. This configuration also enables inli lealced from the inlr supply port 507m or inlc lealied from the inlr supply port 507c to be lcept in the first groove 580, t1111s suppressing diffusion of the lealred inlc along the wall surface of the bottom wall 522 and preventing contamination by the lealced inlr. The cartridge 5 of the embodiment can suppress diffusion of leaked ink by the si~nplest ructure of the first groove 580 formed between the ink supply port 507m which is located between the first side wall 525 and the second side wall 526 and the inlc supply port 507c which is located between the inlc supply port 507m and the second side wall 526 and extended from the second end wall 524 toward the first end wall 523. [OO~O] As sho\vn in Fig. 14, the contacts of the terminals 512 provided on the circuit substrate 510 located on the outer \vall surface of the fist end wall 523 in the cartridge 5 of the embodiment are electrically connectable with the electrode assembly 810 of the carriage 8 (Fig. 6). In the plan view of the cartridge 5 in the direction &om the bottonl wall 522 toward the cover 501, the ink supply port 507y is located bel;\vcen the first groove 580 and the circ~ustu bstrate 510. The ink lealred from the ink s~~ppployr t 507y is kept in the first groove 580. This conGguration suppresses the lealred inli from flowing along the wall surface of the bottom wall 522 and reaching the first end wall 523, thus red~~cinthge likelihood that the terminals 512 ere exposed to the lealced ink. [0081] As shown in Fig. 16, the cartridge 5 of the embodiment has the first groove 580 formed as a concave in the partition wall 572 which parts the recess 521m and the recess 521c fkom each other. This configuration of the cartridge 5 of the embodiment enables the first groove 580 to be readily formed without reducing the capacities of the recesses 521m and 521c for containing inlrs. [00821 In the plane view of the cartridge 5 in the direction from the bottom mall 522 toward the cover 501, the cartridge 5 of the embodiment has the first groove 580 located between the peripheral concaved area 507b and the second end wall 524. The cartridge 5 of the embodiliient accordingly enhances the effectiveness of keeping inlr lealred from the inlr supply port 507y in the first groove 580 and thereby s~ippressingd iffusion of the leaked inlr along the wall surface of the bottom wall 522 described above and tlie effectiveness of preventing contamination by the lealred inlr by tllc simple structure of tlie &st groove 580 adequately positioned. [0083] As illnstrated in Fig. 17, the cartridge 5 of the embodinlent has the second groove 581 formed in the second end wall 524 to be continuous with the &st groove 580. When the cartridge 5 is inclined to be attached to the carriage 8 as shown in Fig. 18, the second groove 581 approaches tlie guide projection 723 of the cartridge attachment structure 7 of the carriage 8 earlier tlian tlie first groove 580. In the cartridge 5 of the embodiment, the second groove 581 contin~lousw ith tlie first groove 580 first receives tlie guide projection 723 in tlie course of attachment of the cartridge 5 to tlie carriage 8. Insertion of the guide projection 723 into the second groove 581 causes the guide projection 723 to serve as a guide rail in the X-axis direction. Tliis configuration of the cartridge 5 of the enlbocliment facilitates attachment of the cartridgc 5 to tlie carriage 8 and enhances the fit of the cartridge 5. [0084] In tlie cartridge 5 of tlic embodiment, the second groove 581 in the second end \\,all 524 is formed to have the shallower depth in the direction froin the botton~w all 522 toward tlie cover 501 than the depth of tl?e first groove 580 in the direction from the bottom wall 522 toward the cover 501. As described above, in the course of attachment of the cartridge 5 to the carriage 8, the cartridge 5 is inclined, so that the guide projection 723 of tlie cartridge attachnient structure 7 of tlie carriage 8 first enters the seconcl groove 581 of the cartridge 5. Setting the depth of the second groove 581 sliallo\ver than the depth of the first groove 580 prevents the second end wall 524 fsom excessively coming close to the liqrucl introducing part 710111 or the liquid introducing part 710c of the cartridge attachment structure 7. This configuration of the cartridgc 5 of tlie embodin~enpt revents tlie second end wall 524 fsom carelessly coming into contact wit11 the liquid introducing part 710111 or 710c or its periphery of the cartridge attachment structure 7 in the course of attachment of the carlridgc 5 to the carriage 8. This is advantageous in terms of avoiding potential damage. coo851 The cartridge 5 of the embodiment has the casing 520 and the circuit substrate 510. The casing 520 has the reccsscs 521111, 521c and 521y config~uredt o separately contain magenta inlr, cyan inlr and yellow ink. Additionally, in the cartridge 5 of the embodiment, the casing 520 has the ink supply ports 507m 507c and 507y and the first groove 580, and the circuit substrate 510 is placed on the casing 520. Thc cartridge 5 of the multi-part struct~woin cluding the casing 520 and the circuit substrate 510 according to the embodiment enables lealred inlr to be kept in the first groove 580 and thereby suppresses diff~~sioonfs t he lealred ink. The invention ]nay be imnplemented by various other aspects described below. [0087] B-1. ltodification ofAppearance of Cartridge Fig. 19 is diagrams illustrating a modification of the appearance of a cartridge 5A in six differen1 views. In the description below, the like components to those of lhe cartridge 5 of the abovc en~bodimenat re expressed by the like numerical sylnbols and are not specifically described here. [O0881 In the plan view of the cartridge 5 of the above embodiment, the direction &om the bottom wall 522 to\vard the cover 501 is set to a first direction. Fig. 19 illustrates a bottom view of the cartridge 5Ain this first direction, a top view of the cartridge 5A in a second direction opposite to the first direction, a &ont view of the cartridge 5A in a tlurd direction orthogonal to the &st direction, a rear viem of the cartridge 5A in a fourthdirection opposite to the third direction, a left side view of the cartridge 5Ain a fiftll direction orthogonal to the first direction and the third ilii.ection and a right side view of the cartridge 5A in a sixth direction opposite to the fifth direction. As illustrated, in the cartridge 5A, appearance 520As of a casing 520A has ctwved ends in the left and right side views, compared with appearance 520s of the casing 520 of the cartridge 5 described above. The degrec of curvature may be greater than the degree of curvature illtlstrated, as long as the area where the first groove 580 and the inlc sul~plyp orts 5071~50 7c and 507y are formed remains as flat surface. The cartridge 5A has an inlc supply port 507m, an inlr supply port 507c, an inlr supply port 507y, a first groove 580 and a circuit s ~ ~ b s t r a5t1e0 in a specific part of the casing included in the bottom view, and the inlc supply port 507y is located between the .first groove 580 and the circuit substrate 510. [0089] In the carlridge 5A of the different appearance 520As, Llle positional relationship between the h s t groove 580 and the inlc sul~plyp ort 507y enables inlc leaked from the inlr supply port 507y to be lrept in the first groove 580 and suppresses diff~~sioofn t he lealred inlc along the wall surface of the bottom wall 522, thus preventing contamination by the lealred ink. [0090] As shown in the bottom plan view of the cartridge 5A in the h s t direction, this cartridge 5A also has the inlr supply port 507y located bet~veen the first groove 580 and the circuit substrate 510. This configuration enables lealred inlc to be lrept in the first groove 580 and suppresses diffusion of the lealced inlc along the wall s~wfaceo f the bottom xvall522 toward the circuit substrate 510, thus reducing the lilrelihood that the circuit substrate 510 is exposed to the lealred inlc. [00911 B-2. Cartridge Using Outer Casing Fig. 20 is diagrams illustrating a schematic exploded view of a cartridge 5B according to a first modification using an outer casing, with a view in a direction A. The cartridge 5B has an outer casing 520out and an inner casing 520in. The outer casing 520out has the appearance similar to that of the casing 520 of the above embodiment except the bottom wall 522 and has a casing insertion openilig 52011. The inner casing 520 in has recesses 521111 521c and 521y configured to separately contain the respective color inlcs, magenta, cyan and yellow and has ink supply ports 507111, 507c and 507y and a first groove 580 in a bottonl wall 522. These recesses an inlr supply ports have the similar configurations to those of the casing 520 described above. The outer casing 520out also has a circuit substrate 510 electrically connectable with the electrode assembly 810 of the carriage 8. The outer casing 520out is attachable to and detachable fro111 the inner casing 520in thro~~ginlls ertion of the inner casing 520in into the casing insertion opening 52011. The cartridge 5B in the state that the inner casing 520in is inserted in the casing insertion opening 52011 of the outer casing 520out is colnpatible with the cartridge 5 of the above embodiment. Positioning pins, steps and the lilrc are formed, though not being illustrated, between the outer wall of the inner casing 520in and the inner wall of the casing insertion opening 52011 to position the inner casing 520in in the Z-axis direction. [0092] When each color ink is consumed and used up to be replaced, the cartridge 5B of this lllodification allows for ink refill by sinlple replacement of the inner casing 520in. The cartridge 5B of the multi-part structure including the separable inner casing 520in and outer casing 520out enables lealred ink to be lrept in the fwst groove 580 and suppresses diffusion of the lealred ink along the wall surface of the bottom \\la11 522 toward the circuit substrate 510, thus reducing the likelil~oodt hat the circuit s~~bstra5t1e0 is exposed to the lealred ink. Lo0931 Fig. 21 is diagrams illustrating a perspective bottonl view of an outer casing 520out in a cartridge 5C according to a second modification using the outer casing, with a .iie\v in a direction A. Fig. 22 is diagrams illustrating a perspective bottom view of inner casings for respective color inlrs in the cartridge 5C, with a view in a direction A. Fig. 23 is a schematic exploded view of the cartridge 5C. The cartridge 5C has an outer casing 520out and inner casings 520inm, 520inc and 520iny. The outer casing 520out has the appearance similar to that of the above casing 520 including the bottom wall 522. As illustrated in Fig. 21, ink supply ports 507m 507c and 507y, and a first groove 580 are formed in a bottom ~vall522of the outer casing 520out. The respective inlr supply ports and the circuit substrate 510 have sinlilar configurations and are formed at similar positions to those of the casing 520 of the above cmbodi~nent. The outer casing 520out has the bottom wall 522, a first end wall 523, a second end wall 524, a first side mall 525 and a second side ~i~all52su6r rounding the bottom wall 522, and partition walls 571 to 573 to define casing-receiving recesses 521ma, 521ca and 521ya to individually receive the inner casings 520inln, 520inc and 520i11y described belo~v. These casing-receiving recesses 521ma, 521ca and 521ya are supposed to receive the inner casings 520inm, 520inc and 520iny liquid-tightly, so that the bottonl wall 522 has the flat inner wall surface. [00941 The inner casing 520inm has the external shape to allow for insertion into tlye casing-receiving recess 521ma of the outer casing 5200ut and has a recess 521111. The recess 521111 is formed to have the similar internal shape to that of the recess 521m of the casing 520 of the above embodiment and causes the l i q ~ ~riedta ining member 5GO and the supply port-side liq~liclr etaining member 506 to be placed therein. Tile inner casing 5071na has a through hole 5071na which is aligned with the ink supply port 507m of the outer casing 5200ut and has a seal member cz arranged lo < seal the periphery of the tl~roughh ole 507ma. In the state that the inner casing 520inm is placed in the casing-receiving recess 521ma of the outer casing 5200ut, magenta ink is supplied from the ink st~pplyp ort 507111 through the through hole 507ma sealed ~vilhth e seal meml~erc z into the liquid introducing part 710x1 of the carriage 8 (Fig. 4). The inner casing 520inc and the inner casing 520iny have similar configurations. [0095] The inner casing 520inm, the inner casing 520inc and the inner casing 520iny are respectively connected with the ink supply port 507111, the ink supply port 507c and tlie ink supply port 507y. This configuration allo~vsm agenta ink to be s~~ppliethdr ough the inlc supply port 507m into the liquid introducing part 710m of the carriage 8 (Fig. 41, allows cyan inlr to be supplied through the ink supply port 507c into the liquid introducing part 710c and allows yellow ink to be supplied through the ink supply port 507y into the liquid introducing part 710y. Placing the inner casings'520inm, 520inc and 520iny into the corresponding casing-receiving recesses 521ma, 521ca and 521ya of the outer casing 5200ut completes the cartridge 5C as shown in Pig. 23. The cartridge 5C is colnpatible with the cartridge 5 of the above embodiment. Positioning pins, steps and the like are formed, though not being illustrated, between the inner walls of the casing-receiving recesses 521ma, 521ca and 521ya of Ll~eo uter casing 520out and the outer walls of the inner casings 520i1lm, 520inc and 520i1ly to position the inner casings 520inm, 520inc and 520iny in the Z-axis direction. [OO~G] MJhen each color inlr is consumed and used up to be replaced, the cartridge 5C of this modificatio~al llo\vs for ink refill by simple replacement of the inner casing 520inm, the inner casing 520inc or the inner casing 520iny. The cartridge 5C of the m~dtiparstt ructure including the separable inner casings 520inm, 520inc and 520iny and outer casing 520out enables lealzed ink to be lzcpt in the first groove 580 and suppresses diffusion of the lealzed inlz along the wall s~~rfaocfe t he bottom wall 522 toward the circuit substrate 510, thus reducing the lilzelihood that the circuit substrate 510 is exposed to the lealzed ink. [0097] Fig. 24 is a schematic exploded view illustrating a cartridge 5D according to a third niodification using the outer casing. The cartridge 5D has an outer casing 520out and an inner casing 520in. The outer casing 520out is substantially similar to that of the second lnodificatioii described above, while the inner casing 520in is equivalent to an integral body of the inner casings 520inm, 520inc and 520iny of the above second modification. In this cartridge 5D, the outer casing 520out does not have partition walls 571 and 573 and has a partition wall 572 having such a height as to allow for formation of a first groove 580. For example, the partition wall 5i2 may be formed to have half the height illustrated in Fig. 17, and the first groove 580 is formed in the partition wall 572. The inner casing 520in has a recess 580c located between a through hole 507ma and a through hole 507ca and configured to receive the partition wall 572 with the first groove 580. The cartridge 5D of the multi-part structure also sul~pressesd iffiision of lealzed ink and other advantageous effects described above. [0098] Fig. 25 is a schelllatic exploded view illustrating a cartridge 5E according to a fourth lnodification using the outer casing. The cartridge 5E has external tanks 590Tm, 59OTc and 59OTy for the respective color inks, magenta, cyan and yellow and tubes 590Cm, 590Cc and 590Cy for the respective color inlzs, in addition to an outer casing 520out and inner casings 520inm, 520inc and 520iny. The outer casing 520out is similar to that of the third modifteation described above, while the inner casings 520inm, 520inc and 520iny are similar to those of the second modification described above. The external t a n b 590Tn1, 590Tc and 590Ty are configured to contain the respective color inks therein and supply the contained color inks by means of internal p111nps (not shown) through the' tubes 590Cm, 590Cc and 590Cy to the inner casings 520inm, 520inc and 520iny. The inner casings 520in1n, 520inc and 520iny have through holes 5071na, 507ca and 507ya as described above in the second modification. These through holes 5071na, 507ca and 507ya are arranged to respectively comnlunicate xvith tlle inlz si~pl~ployr ts 507m, 507c and 507y of the outer casing 520out. The external tank 590Tm and the tube 590Cm are connectable with the inlr supply port 507m; the external tanlr 590Tc and the tube 590Cc are connectable wit11 the inlr supply port 507c; and the external tank 590Ty ant1 thc tube 590Cy arc conncctablc with the inlr s~~ppployr t 507y. This con!iguration allows magcnta ink lo be supplied througll the ink supply port 507m into the liquid introducing part 710111 of the carriage 8 (Fig. 41, allows cyan ink to be supplied through tllc inlr supply port 507c illto the liquid introducing part 710c and allo~vsy ello\v inlr to be supplied tlwougll the ink supply port 507y into the liquid introducing par1 710y. The cartridge 5E of the multi-part struct~urea lso suppresses diffusion of lealred inlr and other advantageous effects described above. The present invention is not limited to the inkjet printer or its ink cartridges but is also applicable to any liqnid ejection device configured to eject another liq~uicbl ut inlr and a cartridge (Liquid container) configured to contain another liquid. For example, the invention may be applied to any of various Liq~ude jection devices and their liquid containers: (1) image recording device, such as a facsimile machine; (2) color material ejection device used to manufacture color filters for an image display device, e.g., a liqnid crystal display; (3) electrode material ejection device used to form electrodes of, for example, an organic EL (electrolumincscence) display and a field emission display (FED); (4) liquid ejection device configured to eject a bioorganic material-containing liquid used for manufacturing bioclGps; (5) sa~npleej ection device used as a precision pipette; (6) ejection device of lubricating oil; (7) ejection device of a resin solution; (8) liquid ejection device for pinpoint ejection of lubricating oil on precision machines such as ~vatcheso r cameras; (9) liquid ejection dcvice configured to eject a transparent resin 39 solution, such as an ultraviolet curable resin solution, onto a substrate in order to manufacture a l~emispl~ericmali crolens (optical lens) used for, for example, optical communication elements; (10) liquid ejection device config~uredto eject an acidic or allraline etching solution in order to etch a substrate or the lilce; and (11) liquid ejection device equipped with a liquid ejection head for ejecting a very s m ~ lvlo lume of droplets of any other liquid. The "droplet" herein means the state of liquid ejected from the liquid ejection device and may be in a granular shape, a teardrop shape or a tapered threadlike shape. The "liquid" herein may be any material ejectable by the liquid ejection device. The "liquid" may be any material in the liquid phase. For example, liquid-state ~naterialso f high viscosity or low viscosity, liquid materials in sol-gel process and other liquid-state materials including inorganic solvents, organic solvents, solutions, liqnid resins and liquid metals (metal melts) are included in the "liquid". The "liq~tid"is not limited to the liquid state as one of the t h e e states of matter but inclndes sol~ttions,d ispersions and mixtures of the functional solid material particles, such as pigment particles or metal particles, solved in, clispersed in or mixed with a solvent. Typical examples of the liquid include ink described in the above embodiment and liquid crystal. The ink herein includes general water-based inks and oil-based inks, as well as various liquid compositions, such as gel inlrs and hot-melt inlrs. [01011 The invention is not limited to any of the embodnnents, the examples and the modifications described herein but may be implemented by a diversity of other configurations without departing from the scope of the invention. For example, the teclmical features of tile embodiments, exa~npleso r modifications corresponding to the tecllnical feat~tresof the respective aspects described in Summary may be replaced or combined appropriately, in order to solve part or all of the problems described above or in order to achieve part or all of the advantageous effects described above. Any of the technical features may be omitted appropriately unless the technical feature is described as essential herein. [0102] In tlie eml~odimenat nd ~uodificationsd escribed above, thc guide projection 723 is provided on tlie cartridge attachment structure 7, while the first groove 580 in which the guide projection 723 is inserted is provicled on the cartridge 5. In one modification, the guide projection 723 shown in Fig. 4 ]nay be replaced by a pl~uralityo f projections protraded discretely along the length from between the liquid introd~~cinpgar t 710m and the liquid introducing part 710c adjacent to each other in thc X-axis direction to the liquid introducing part 710y. The first groove 580 may be formed as a single concave as shown in Fig. 14 or may be fornled as a plurality of concaves in which the plurality of projections are inctivid~~alilnys erted. The definition of "groove" includes not only a dent portion formed on the cartridge 5 but also a slot completely penetrates tlwough the cartridge 5. [0103] This application clainls priorities to Japanese Patent Applications No. (JP) 2013-260964 filed on Decenlber 18, 2013, JP 2013-270007 filed on December 26, 2013, JP 2013-272477 filed on December 27, 2013, JP 2014-015767 filed on January 30,2014, JP 2014-18365 filed on February 3, 2014, JP 2014-29769 filed on Febri~ary 19, 2014, JP 2014-31192 filed on February 21,2014, JP 2014-34847 filed on February 26,2014, JP 2014-37928 filed on February 28, 2014, JP 2014-37929 filed on February 28, 2014, JP 2014-45198 filed on March 7, 2014, JP 2014-57360 filed on Rllarcl~2 0, 2014, JP 2014-61295 filed on March 25, 2014, JP 2014-61296 filed on March 25, 2014, JP 2014-61297 filed on hilarch 25, 2014, and JP 2014-118344 filed on June 9, 2014, entire disclosures of which are incorporated herein by reference for all purposes. IN040A2127-WlpEnglisl~pSpec_for-filing.doc What is Claimed is: I. A liquid supply unit configured to be mountable on a liquid supply unit mounting structure having a first liquid introducing parl, a second liquid introducing part, a third liquid introdncing part and a projection ~vluchis located between the first liquid introducing part and the second liquid introducing part and is located hetween the tlurd liquid introducing part and a part between the first liquid introducing part and the second liquid introducing part, the liquid supply unit comprising: a first liquid supply port configrwed to be connectable with the first liquid introducing part such as to supply a first liquid to the first liquid introducing part; a second liquid supply port configured to be connectable with the second liquid introducing part such as to supply a second liquid to the second liquid introducing part; a third liquid supply port configured to be connectable with the third liquid introducing part such as to supply a third liquid to the third liquid introducing part; and a groove formed between the first liquid supply port and the second liquid supply porl and extended from between the first liquid supply port and the seconcl liquid supply port toward the tlird liquid supply po~ts,u ch as to allow the projection to be inserted therein. 2. The liquid supply unit according to claim l~f,u rther comprising: a first wall configured to have the first liquid supply port, the second liquid supply port, the third liquid supply port and the groove; a second wall opposed to the first wall; a third wall arranged to intersect with the fmt wall and the second wall; a fourth wall arranged to interscct with thc first wall and the second wall and opposed to the third wall; a fifth wall arranged to intersect with the first wall and the second wall; and a sixth wall arranged to intersect with the first wall and the second wall and opposed to the fifth wall, wherein in a plan view of the liquid supply unit in a direction &om the first wall toward the second wall, the first liquid supply port is located between the fifth wall and the sixth wall, the second liquid supply port is located between the first liqnid supply port and the sixth wall, the groove is extended £roll1 the fourth wall toward the third wall, and the third liquid supply port is located bctween the groove and the tl&d wall. 3. The liquid supply unit according to claim 2, fiirther comprising: a contact located on an outer wall surface of the third wall and arranged to be electrically connectable with an electrode on the liquid supply unit mounting structure, wherein in the plan view of the liquid supply unit in the direction &om the first wall toward the second wall, the third liquid supply port is located between the groove and the contact. 4. The liquid supply unit according to either claim 2 or claim 3, further comprising: a first partition ~valalr ranged to intersect mith the first wall and the second wall and located between the fifth \\la11 and the sixth wall; a second partition wall arranged to intersect with the first wall, the second wall and the first partition wall and located between the fourth wall and the third wall; a f ~ slitqu id cl~aml~dcerf ined by at least the first wall, the second wall, the fourth wall, the fifth wall, the firs1 partition wall and the second partition wall and arranged to communicate with the first liquid supply port; a second liquid chamber defined by at least the first wall, the second wall, the fourth wall, the sixth wall, the first partition wall and the second partition wall and arranged to communicate with the second liquid supply port; and a third liquid chalnber defined by at least the first wall, the second wall, the tl~irdw all, the sixth wall and the first parlition wall and arranged to communicate with Llle third liquid supply port, wherein in the plan view of the liquid supply unit in the direction from the fist wall toward the second wall, the groove is located between the fourth wall and Lhe third Liquid chamber. 5. The liquid supply unit according to clainl 4, wherein the groove is formed as a concave in the first partition wall. 6. The liquid supply unit according to any one of clailns 2 to 5, wherein in the plan view of the liquid supply nit in the direction from the first wall Loxvard the second wall, the groove is located between. the foturth wall and a specific area where the first wall is in contact with a third seal element formed around a periphery of the third liquid introducing part of the liquid supply uniL mounting structure. 7. The liquic1 supply unit according to any one of claims 2 to 6, wherein the fourth wall has a concave arranged to be continuous wit11 the groove. 8. The liquid supply unit according to claim 7, wherein tlie concave of the fourth wall has a shallower depth in the direction from the first wall toward the second wall than deptli of the groove in tlie direction from the first wall toward the second wall. 9. The liquid supply unit according to claim 1, the liqt~ids ~lpplyu nit having: a h s t outer shape including the first liquid supply port, the second liqnid supply port, the third liquid supply port, the groove and a contact mlfich is configured to be electrically connectable with an electrode of the liquid s~lpplyu nit mounting structure, in a plan view of the liquid supply unit in a first direction, a second outer shape in a plan view of the liquid supply unit in a second direction opposite to the first direction, a third outer shape including the contact in a plan view of the liquid supply unit in a tlfird direction orthogonal to the first direction, a foulrth enter shape in a plan view of the liquid supply unit in a fourth direction opposite to the third dii-ection, a fifth outer shape in a plan vie\v of thc liquid supply unit in a fifth ~ e c t i o onr thogonal to the first direction and the third direction, and a sixth outer shape in a plan view of the liquid supply unit in a sixth direction opposite to the fifth direction. 10. The Liq~lids upply unit according to claim 9, \vherein the third liquid supply port is located between the groove and the contact in the plan view of tlie liquid sup~llyu nit in the first direction. 11. The liquid sul~plyu nit according to claim 1, f i ~ ~ t l lceorm l~rising: a first member config~uredt o have a liquid chamber scpa~atcly containing the first liquid, tlie second liquid and the third liquid, the first liquid supply port, the second liquid supply port, the t l ~ldiqu id supply port and the groove; and a second member placed on the first member and configured to have a terminal including a contact that is electrically connectable with an electrode of the liquid supply unit nlounting structure. 12. The liquid supply unit according to claim 1, further comnprising: a first member configured to have the first liquid supply port, the second liquid supply port, the t1jl.d liquid supply port and the groove; and a second member configured to be attachable to and detachable from the first mc~nbera nd to have a terminal including a contact that is electrically connectable with an electrode of the liquid supply unit mounting structure. 13. The liquid supply unit according to claim 1, furtlier comprising: a first member config~wedto have the first liq~udsu pply port, tlie second liquid supply port, tlie third liquid supply port, a ternlinal including a contact that is electrically connectable with an electrode of the liquid snpply unit mounting structure, and the groove; and a second inember configured to be attachable to the first liquid supply port, the second liquid supply port and the third liquid supply port, such as to supply the first liquid through the first liquid sul~plyp ort to the first liquid introducing part, supply tlie second liquid thougll the seconil liquid supply port to the second liquid introducing part and supply the third liquid through tlle t1il.d liquid supply port to the third liquid introducing part. 14. Alicluicl sul>ply unit con£ig~ured to be attachable to and cletacl~able horn a liquid ejection clevice, the liq~~iscul~ pplyu nit coml~rising: a groove; a liquid s~q~pployr t tlwougll which a liquid is supplied to the liquid ejection device; and a termiilal assembly co~&gu~e-etdo be electrically co~nlectablew it11 the liquid ejeclion device, wherein the liquid su111ply port is located between the groove and tiie terminal assembly. 15. hliq~iicslr 111l>lyu nit colfig~wedto be attachable to and detachal~le from a liquid ejection device, the liquid supply unil co~nprising: a h s t w all configured to have a groove and a liqu~ids upply port through which a liquid is supplied to the liquid ejection device; a secollcl wall opposed to the first all; a fo~~rwtlall l arranged to intersect \vithl the flrsl wall and the second vrrall; anct . a third wall arranged to intersect wit11 the first ~valaln cl the second wall, opl~osedto the fourth wall and configured to have a terminal asseml~ly vr~l~icish electrically conilectable tvith the liquid ejection clevice, wherein in a plan view of the liquid sr111ply unit in a clirection holu tile fwst wall toward the second vr~al1,-tll~ieq uid supply port is located between the groove and the teyn~illaal ssembly.