JP6435913B2 - Liquid ejecting apparatus and maintenance method for liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as a printer and a maintenance method for the liquid ejecting apparatus.

  In an ink jet printer that is an example of a liquid ejecting apparatus, a cleaning agent is ejected in the form of a mist onto a nozzle that ejects ink to dissolve the solid component of the ink fixed around the nozzle or in the vicinity of the opening. After that, there is one that removes the dissolved material by blowing it off by gas discharge (for example, Patent Document 1).

JP 2002-178529 A

  By the way, as described above, when the cleaning liquid is discharged toward the nozzle opening for ejecting the ink and the clogging of the nozzle is eliminated, the clogged solid component enters the nozzle inner tub, and this occurs during printing. There is a problem that ejection failure occurs when the ink is supplied to the nozzle together with the ink.

  Note that such a problem is not limited to the case where the clogging of the nozzle is eliminated by discharging the cleaning liquid to the opening of the nozzle, but is generally common when foreign matter exists on the upstream side of the nozzle. .

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid ejecting apparatus capable of discharging foreign matter present in a liquid ejecting section having a plurality of nozzles and a maintenance method for the liquid ejecting apparatus. There is.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The liquid ejecting apparatus that solves the above-described problem is a common liquid chamber capable of storing a first liquid supplied via a liquid supply path, and the first liquid that communicates with the common liquid chamber and that is supplied from the common liquid chamber. A liquid ejecting unit having a plurality of nozzles capable of ejecting a liquid to the medium, and a fluid injecting device capable of injecting at least one of a gas and a second liquid into the liquid ejecting unit through the opening of the nozzle. The fluid injecting device injects the fluid into the liquid ejecting unit through an opening of one of the plurality of nozzles, and causes the fluid containing the first liquid to be injected into the other nozzle among the plurality of nozzles. Perform fluid injection maintenance to drain through the opening.

  According to this configuration, the fluid injection device injects the fluid into the liquid ejecting unit through the opening of one nozzle, so that a plurality of nozzles and the foreign matters in the common liquid chamber that these nozzles communicate with are in the common liquid chamber. Together with the first liquid, it can be discharged from the opening of another nozzle. Therefore, foreign matter existing in the liquid ejecting unit having a plurality of nozzles can be discharged.

  The liquid ejecting apparatus includes a supply restricting unit capable of restricting a liquid flow in the liquid supply path, and the fluid injecting device performs the fluid injection maintenance in a state where the supply restricting part restricts the liquid flow. .

  According to this configuration, the fluid that has been injected from the nozzle by the fluid injection device does not flow to the upstream side when the supply restricting unit restricts the flow of the liquid, so that the injected fluid is efficiently discharged from the other nozzles. Can be made.

  In the liquid ejecting apparatus, after the fluid injection device performs the fluid injection maintenance in a state where the supply restricting portion restricts the flow of the liquid, the liquid supply path in a state where the supply restricting portion releases the restriction. The first liquid is supplied from the upstream side of the nozzle and filled with the first liquid up to the opening of the nozzle.

  According to this configuration, in the process of supplying the first liquid from the upstream side of the liquid supply path and filling the first liquid to the opening of the nozzle, the fluid injection device injects from the nozzle instead of the first liquid to be filled. Since the second liquid is discharged, the foreign matter in the common liquid chamber can be discharged together with the second liquid. Further, by filling the first liquid up to the opening of the nozzle, it is possible to prepare for the next liquid ejection operation.

In the liquid ejecting apparatus, a filter is provided between the supply restricting unit and the common liquid chamber in the liquid supply path.
According to this configuration, the filter positioned between the supply restricting portion and the common liquid chamber can suppress foreign matter from flowing toward the supply restricting portion along the flow of the fluid injected from the nozzle. . In addition, the fluid injected from the nozzle applies pressure from the downstream side of the filter, so that solids and the like accumulated on the upstream side of the filter can be peeled off from the filter.

  In the liquid ejecting apparatus, the liquid ejecting unit includes a pressure generating chamber communicating with the common liquid chamber and the nozzle, and an actuator capable of pressurizing the pressure generating chamber. When the apparatus injects the fluid into the one nozzle, the actuator corresponding to the other nozzle different from the one nozzle is driven.

  According to this configuration, by driving an actuator corresponding to another nozzle different from the nozzle into which the fluid is injected by the fluid injection device, it is possible to promote the discharge of the fluid from the other nozzle.

  In the liquid ejecting apparatus, the fluid injecting apparatus has an ejection port capable of ejecting the second liquid, and ejects the fluid from the ejection port in a state where the ejection port is separated from the liquid ejecting unit. Thus, the fluid is injected into the opening of at least one of the plurality of nozzles.

  According to this configuration, since the ejection port from which the fluid injecting device ejects the second liquid is disposed at a position away from the liquid ejecting unit, the adhesion of the first liquid ejected by the liquid ejecting unit to the ejection port is suppressed. Can do.

  In the liquid ejecting apparatus, the fluid injecting apparatus ejects a fluid containing small droplets of the second liquid that is smaller than the opening of the nozzle, thereby causing the fluid injecting apparatus to pass through the opening of one of the plurality of nozzles. The fluid is injected into the liquid ejecting unit.

  According to this configuration, when the fluid injection device ejects a fluid containing a small droplet of the second liquid smaller than the opening of the nozzle, the clogging of the nozzle can be eliminated by the energy with which the small droplet collides. it can. When the foreign matter that has caused clogging of the nozzle enters the common liquid chamber in the nozzle, the foreign matter can be discharged by fluid injection maintenance performed by the fluid injection device. Therefore, the configuration of the liquid ejecting apparatus can be simplified as compared with the case where a device for eliminating clogging of the nozzle is separately provided because the device for eliminating clogging of the nozzle is also used as the fluid injection device. .

  In the liquid ejecting apparatus, the product of the mass of the small liquid droplet and the square of the flying speed of the small liquid droplet at the opening position of the nozzle is the product of the first liquid droplet ejected from the nozzle opening. It is larger than the product of the mass and the square of the flying speed of the droplet.

  The kinetic energy of the droplet ejected by the fluid injection device is obtained by the product of the mass of the droplet and the square of the flying speed of the droplet at a predetermined position, and the liquid ejecting unit ejects the first liquid from the nozzle. If the kinetic energy of the droplet is large, even if the nozzle is slightly clogged, the clogging can be eliminated by the energy of the droplet. On the other hand, when the nozzle is severely clogged, the clogging cannot be eliminated by the energy for ejecting the first liquid droplet from the nozzle. In that regard, according to the above configuration, the kinetic energy at the nozzle opening position of the small liquid droplets ejected from the ejection port toward the nozzle by the fluid injection device is larger than the energy at which the first liquid droplet is ejected from the nozzle. . Therefore, clogging of the nozzle that cannot be eliminated by the ejection operation of ejecting the first liquid droplet from the nozzle opening is eliminated by the kinetic energy when the second liquid droplet ejected by the fluid injection device enters the nozzle. can do.

In the liquid ejecting apparatus, the second liquid is pure water or a liquid containing a preservative in pure water.
According to this configuration, by making the main component of the second liquid pure water, even when the second liquid enters the nozzle, the deterioration due to mixing with the second liquid of the first liquid in the nozzle is prevented. Can be suppressed. Moreover, when the antiseptic | preservative is contained in the pure water which is a main component, the decay of the 2nd liquid hold | maintained in the fluid injection apparatus can be suppressed.

  A maintenance method for a liquid ejecting apparatus that solves the above problem includes a common liquid chamber capable of storing a first liquid supplied via a liquid supply path, and a common liquid chamber that communicates with the common liquid chamber and is supplied from the common liquid chamber. A liquid ejecting unit having a plurality of nozzles capable of ejecting the first liquid to the medium; and a fluid injecting device capable of injecting at least one of the gas and the second liquid into the liquid ejecting unit through the opening of the nozzle; A liquid ejecting apparatus maintenance method comprising: an injecting step of injecting the fluid into the liquid ejecting unit through an opening of one of the plurality of nozzles; and an injection of the fluid injected in the injecting step A discharge step of discharging a fluid containing the first liquid in the liquid ejecting section through an opening of another nozzle among the plurality of nozzles by pressure.

  According to this configuration, it is possible to obtain the same effect as that of the liquid ejecting apparatus.

The schematic diagram which shows one Embodiment of a liquid ejecting apparatus. FIG. 3 is a plan view schematically showing the arrangement of components of the liquid ejecting apparatus. The bottom view of a head unit. The disassembled perspective view of a head unit. FIG. 4 is a cross-sectional view taken along line A-A ′ in FIG. 3. The disassembled perspective view of a liquid injection part. The top view of a liquid injection part. 7A is a cross-sectional view taken along the line BB ′ in FIG. 7, FIG. 7B is an enlarged view of the right-hand dashed line frame in FIG. 7A, and FIG. Enlarged view. The top view which shows the structure of a maintenance apparatus. The schematic diagram which shows the structure of the fluid injection apparatus of 1st Embodiment. The perspective view of the injection unit of a 1st embodiment. The side cross-sectional schematic diagram which shows the use condition of the injection unit of 1st Embodiment. FIG. 3 is a block diagram illustrating an electrical configuration of the liquid ejecting apparatus. The side cross-sectional schematic diagram which shows the use condition of the injection unit of 1st Embodiment. The side cross-sectional schematic diagram which shows the standby state of the injection unit of 1st Embodiment. The schematic diagram which shows the structure of the fluid injection apparatus of 2nd Embodiment. The table | surface which shows the operation mode of the fluid injection apparatus of 2nd Embodiment. Explanatory drawing of the wiping performed by making a foam-like 2nd liquid adhere. Explanatory drawing of the capping performed by making a foamy 2nd liquid adhere. The schematic diagram which shows the nozzle after making the 2nd liquid adhere. Explanatory drawing of the fluid injection | pouring maintenance which the fluid injection apparatus of 2nd Embodiment performs. The schematic diagram which shows the example of a change of a liquid injection part. The schematic diagram which shows the example of a change of a fluid injection nozzle.

  Hereinafter, as an example of a liquid ejecting apparatus, an embodiment of an ink jet printer that ejects liquid ink and prints an image including characters, figures, and the like will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the liquid ejecting apparatus 7 includes a transport unit 713 that transports the sheet-like medium ST supported by the support base 712 along the surface of the support base 712 in the transport direction Y, and the transported medium ST. In addition, a printing unit 720 that performs printing by ejecting ink as an example of the first liquid, and a heat generation unit 717 and an air blowing unit 718 for drying the ink that has landed on the medium ST are provided.

  The support base 712, the transport unit 713, the heat generating unit 717, the air blowing unit 718, and the printing unit 720 are assembled to the printer main body 11a including a housing, a frame, and the like. In the printer main body 11a, the support base 712 extends in the width direction of the medium ST (a direction orthogonal to the paper surface in FIG. 1).

  The transport unit 713 includes a transport roller pair 714 a and a transport roller pair 714 b that are disposed on the upstream side and the downstream side of the support base 712 in the transport direction Y and are driven by a transport motor 749 (see FIG. 13). Further, the transport unit 713 includes a guide plate 715a and a guide plate 715b that are arranged on the upstream side of the transport roller pair 714a and the downstream side of the transport roller pair 714b in the transport direction Y and guide the medium ST while supporting it. Yes.

  The transport unit 713 transports the medium ST along the surfaces of the guide plate 715a, the support base 712, and the guide plate 715b by rotating the transport roller pair 714a and 714b while sandwiching the medium ST. In the present embodiment, the medium ST is continuously conveyed by being fed out from the roll sheet RS wound around the supply reel 716a. The medium ST that is fed out from the roll sheet RS and continuously conveyed is wound up in a roll shape by the take-up reel 716b after the printing unit 720 has ink attached thereto and an image is printed.

  The printing unit 720 is guided by guide shafts 721 and 722 extending along the scanning direction X, which is the width direction of the medium ST perpendicular to the transport direction Y of the medium ST, and the carriage motor 748 (see FIG. 13). A carriage 723 that can reciprocate in the scanning direction X by power is provided. In the present embodiment, the scanning direction X is a direction that intersects (as an example, orthogonal) with both the transport direction Y and the gravity direction Z.

  The carriage 723 is supplied through two liquid ejecting sections 1 (1A, 1B) that eject ink, a liquid supply path 727 that supplies ink to the liquid ejecting sections 1 (1A, 1B), and a liquid supply path 727. A storage unit 730 for temporarily storing the ink that has been used and a flow path adapter 728 connected to the storage unit 730 are provided. The storage unit 730 is held by a storage unit holding body 725 attached to the carriage 723. In the present embodiment, the ejection direction of the ink droplet (droplet) from the liquid ejecting unit 1 is the gravity direction Z.

  The reservoir 730 includes a differential pressure valve 731 provided in the middle of the liquid supply path 727 for supplying ink to the liquid ejecting unit 1. The differential pressure valve 731 is opened when the pressure of the ink on the downstream side becomes a predetermined negative pressure with respect to the atmospheric pressure as the ink is ejected (consumed) in the liquid ejecting units 1A and 1B located on the downstream side thereof, When ink is supplied from the reservoir 730 to the liquid ejecting units 1A and 1B by opening the valve, and the negative pressure on the downstream side is eliminated, the valve is closed. The differential pressure valve 731 does not open even when the pressure of the ink on the downstream side increases, and allows the supply of ink from the upstream side (the storage unit 730 side) to the downstream side (the liquid ejecting unit 1 side). Therefore, it functions as a one-way valve (check valve) that suppresses the back flow of ink from the downstream side to the upstream side.

  The liquid ejecting unit 1 is attached to the lower end portion of the carriage 723 so as to face the support base 712 at a predetermined interval in the gravity direction Z. On the other hand, the storage unit 730 is attached to the upper side which is opposite to the liquid ejecting unit 1 in the gravity direction Z with respect to the carriage 723.

  An upstream end portion of the supply tube 727a constituting a part of the liquid supply path 727 has a downstream end portion of a plurality of ink supply tubes 726 that can be deformed following the reciprocating carriage 723, and a part of the carriage 723. It is connected via a connection part 726a attached to the. Further, the downstream end of the supply tube 727 a is connected to the flow channel adapter 728 at a position above the storage unit 730. Therefore, for example, ink from an ink tank (not shown) containing ink is supplied to the storage unit 730 via the ink supply tube 726, the supply tube 727 a, and the flow path adapter 728.

  In the printing unit 720, in the process in which the carriage 723 moves (reciprocates) in the scanning direction X, ink is applied to the medium ST on the support base 712 from the openings of the plurality of nozzles 21 (see FIG. 3) of the liquid ejecting unit 1. Spray. The heat generating unit 717 for heating and drying the ink that has landed on the medium ST is disposed at an upper position in the liquid ejecting apparatus 7 at a predetermined length in the gravity direction Z from the support base 712. The printing unit 720 can reciprocate along the scanning direction X between the heat generating unit 717 and the support base 712.

  The heat generating portion 717 includes a heat generating member 717a such as an infrared heater and a reflecting plate 717b extending along the same scanning direction X as the extending direction of the support base 712. In the area indicated by the one-dot chain arrow in FIG. The ink adhering to the medium ST is heated by radiated heat such as infrared rays (for example, radiant heat). In addition, the air blowing unit 718 that dries the ink attached to the medium ST by the air blowing is disposed at an upper position with a space that allows the printing unit 720 to reciprocate in the liquid ejecting apparatus 7.

  A heat shield member 729 that blocks heat transfer from the heat generating portion 717 is provided at a position between the storage portion 730 and the heat generating portion 717 in the carriage 723. The heat shielding member 729 is made of a metal material having good thermal conductivity such as stainless steel or aluminum, and covers at least the upper surface portion of the storage portion 730 facing the heat generating portion 717.

  In the liquid ejecting apparatus 7, the storage unit 730 is provided at least for each ink type. The liquid ejecting apparatus 7 of the present embodiment includes a storage unit 730 that stores colored ink, and can perform color printing and monochrome printing. For example, the ink colors of the colored ink are cyan, magenta, yellow, black, and white. Each colored ink contains a preservative.

  White ink is used for base printing (also referred to as solid printing or solid printing) before color printing, for example, when the medium ST is a transparent or translucent film or a dark medium. Is done. Of course, the color ink to be used can be arbitrarily selected, and may be, for example, three colors of cyan, magenta, and yellow. In addition to the above three colors, at least one color among light cyan, light magenta, light yellow, orange, green, gray, and the like can be further added to the colored ink.

  As shown in FIG. 2, the two liquid ejecting units 1A and 1B attached to the lower end portion of the carriage 723 are arranged so as to be separated by a predetermined distance in the scanning direction X and shifted by a predetermined distance in the transport direction Y. ing. Further, a temperature sensor 711 is provided at a position between the two liquid ejecting units 1A and 1B in the scanning direction X at the lower end of the carriage 723.

  The moving region in which the liquid ejecting units 1A and 1B can move in the scanning direction X is movable in the scanning direction X and the printing region PA in which ink can be landed from the nozzles 21 of the liquid ejecting units 1A and 1B when the medium ST is printed. The liquid ejecting units 1A and 1B include non-printing areas RA and LA that are areas outside the printing area PA that does not face the medium ST being conveyed. An area corresponding to the print area PA in the scanning direction X is a heating area HA provided with a heat generating portion 717 for fixing the ink landed on the medium ST by heating.

  The maximum width area in the scanning direction X in which the ink droplets ejected from the liquid ejecting units 1A and 1B can land on the medium ST having the maximum width conveyed on the support base 712 is a print area PA. Yes. That is, ink droplets ejected from the liquid ejecting units 1A and 1B onto the medium ST land in the printing area PA. When the printing unit 720 has a borderless printing function, the printing area PA is slightly wider in the scanning direction X than the range of the medium ST having the maximum width to be conveyed.

  The non-printing areas RA and LA exist on both sides of the printing area PA in the scanning direction X (on the right and left sides in FIG. 2, respectively). In the non-printing area LA located on the left side of the printing area PA in FIG. 2, a fluid ejecting device 775 for performing maintenance of the liquid ejecting unit 1 is provided. On the other hand, a wiper unit 750, a flushing unit 751, and a cap unit 752 are provided in the non-printing area RA located on the right side of the printing area PA in FIG.

  The fluid ejecting device 775, the wiper unit 750, the flushing unit 751, and the cap unit 752 constitute a maintenance device 710 for performing maintenance of the liquid ejecting unit 1. The position where the cap unit 752 is located in the scanning direction X is the home position HP of the liquid ejecting units 1A and 1B.

<About the configuration of the head unit>
Next, the configuration of the head unit 2 will be described in detail.
The liquid ejecting unit 1 includes a plurality (four in the present embodiment) of head units 2 provided for each ink color (each liquid type).

  As shown in FIG. 3, one head unit 2 has a large number (for example, 180) of nozzles 21 for ejecting ink at a fixed nozzle pitch in one direction (in the present embodiment, the transport direction Y). The nozzle rows NL are configured by being arranged.

  In this embodiment, two nozzle rows NL aligned in the scanning direction X are provided in one head unit 2, so that two rows located close to each other in one liquid ejecting unit 1 are in the scanning direction. A total of eight nozzle rows NL arranged at regular intervals in X are formed. The two liquid ejecting units 1 are configured such that when a large number of nozzles 21 constituting each nozzle row NL are projected in the scanning direction X, the distance between the nozzles 21 at the end portions can be the same nozzle pitch. The positional relationship is in the direction Y.

  As shown in FIG. 4, the head unit 2 includes a plurality of members such as a head main body 11 and a flow path forming member 40 fixed to one surface (upper surface) of the head main body 11. The head body 11 includes a flow path forming substrate 10, a communication plate 15 provided on one surface (lower surface) side of the flow path forming substrate 10, and a surface (lower surface) side of the communication plate 15 opposite to the flow path forming substrate 10. , The protective substrate 30 provided on the opposite side (upper side) of the communication plate 15 of the flow path forming substrate 10, and the surface side of the communication plate 15 on which the nozzle plate 20 is provided. And a compliance substrate 45.

  The flow path forming substrate 10 can be made of a metal such as stainless steel or Ni, a ceramic material typified by ZrO 2 or Al 2 O 3, a glass ceramic material, an oxide such as MgO or LaAlO 3. In the present embodiment, the flow path forming substrate 10 is made of a silicon single crystal substrate.

  As shown in FIG. 5, the flow path forming substrate 10 is provided with a plurality of nozzles 21 in which pressure generation chambers 12 partitioned by a plurality of partition walls discharge ink by performing anisotropic etching from one side. It is arranged along the direction. The flow path forming substrate 10 is provided with a plurality of rows (two rows in the present embodiment) in which the pressure generation chambers 12 are arranged in parallel in the transport direction Y and are arranged in the scanning direction X.

  Supply to the flow path forming substrate 10 is provided with a flow path resistance of ink flowing into the pressure generation chamber 12 on one end side in the transport direction Y of the pressure generation chamber 12 and having an opening area smaller than that of the pressure generation chamber 12. A road or the like may be provided.

  As shown in FIGS. 4 and 5, the communication plate 15 and the nozzle plate 20 are stacked in the gravitational direction Z on one surface (lower surface) side of the flow path forming substrate 10. That is, the liquid ejecting unit 1 is a nozzle in which a communication plate 15 provided on one surface of the flow path forming substrate 10 and a nozzle 21 provided on the opposite surface side of the communication plate 15 from the flow path forming substrate 10 are formed. Plate 20.

  The communication plate 15 is provided with a nozzle communication path 16 that communicates the pressure generating chamber 12 and the nozzle 21. The communication plate 15 has a larger area than the flow path forming substrate 10, and the nozzle plate 20 has a smaller area than the flow path forming substrate 10. By providing the communication plate 15 in this way, the nozzle 21 of the nozzle plate 20 and the pressure generation chamber 12 can be separated from each other, so that the ink in the pressure generation chamber 12 is evaporated by the moisture in the ink from the nozzle 21. It becomes difficult to thicken. Further, since the nozzle plate 20 only needs to cover the opening of the nozzle communication passage 16 that communicates the pressure generating chamber 12 and the nozzle 21, the area of the nozzle plate 20 can be made relatively small, and the cost can be reduced. Can do.

  As shown in FIG. 5, the communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 (throttle channel, orifice channel) that constitute a part of the common liquid chamber (manifold) 100. It has been. The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the thickness direction (the gravitational direction Z that is the stacking direction of the communication plate 15 and the flow path forming substrate 10). The second manifold portion 18 is provided to open to the nozzle plate 20 side of the communication plate 15 without penetrating the communication plate 15 in the thickness direction.

  Further, the communication plate 15 is provided with a supply communication passage 19 that communicates with one end of the pressure generation chamber 12 in the transport direction Y independently for each pressure generation chamber 12. The supply communication path 19 communicates the second manifold portion 18 and the pressure generation chamber 12.

  As the communication plate 15, a metal such as stainless steel or nickel (Ni), or a ceramic such as zirconium (Zr) can be used. The communication plate 15 is preferably made of a material having the same linear expansion coefficient as the flow path forming substrate 10. That is, when a material having a linear expansion coefficient significantly different from that of the flow path forming substrate 10 is used as the communication plate 15, the flow path forming substrate 10 and the communication plate 15 are warped by being heated or cooled. In this embodiment, by using the same material as the flow path forming substrate 10 as the communication plate 15, that is, a silicon single crystal substrate, it is possible to suppress the occurrence of warping due to heat, cracking due to heat, peeling, and the like.

  Of the two surfaces of the nozzle plate 20, the surface (lower surface) that discharges ink droplets, that is, the surface opposite to the pressure generating chamber 12 is referred to as a liquid ejecting surface 20 a, and the opening of the nozzle 21 that opens to the liquid ejecting surface 20 a This is called an opening.

  As the nozzle plate 20, for example, a metal such as stainless steel (SUS), an organic material such as polyimide resin, a silicon single crystal substrate, or the like can be used. In addition, by using a silicon single crystal substrate as the nozzle plate 20, the linear expansion coefficients of the nozzle plate 20 and the communication plate 15 are made equal, and the occurrence of warpage due to heating or cooling, cracks due to heat, peeling, and the like are suppressed. can do.

  On the other hand, a diaphragm 50 is formed on the surface of the flow path forming substrate 10 opposite to the communication plate 15. In the present embodiment, an elastic film 51 made of silicon oxide provided on the flow path forming substrate 10 side and an insulator film 52 made of zirconium oxide provided on the elastic film 51 are provided as the diaphragm 50. Yes. The liquid flow path such as the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one side (the side where the nozzle plate 20 is bonded). The other surface of the liquid flow path is defined by the elastic film 51.

  An actuator (piezoelectric actuator) 130 having a first electrode 60, a piezoelectric layer 70, and a second electrode 80, which is a pressure generating unit of the present embodiment, is provided on the vibration plate 50 of the flow path forming substrate 10. Yes. Here, the actuator 130 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80.

  In general, any one electrode of the actuator 130 is used as a common electrode, and the other electrode is patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is continuously provided across the plurality of actuators 130 to be a common electrode, and the second electrode 80 is independently provided for each actuator 130 to be an individual electrode.

  Of course, there is no problem even if it is reversed for the convenience of the drive circuit and wiring. In the above-described example, the diaphragm 50 includes the elastic film 51 and the insulator film 52. However, the present invention is not limited to this. For example, the diaphragm 50 may be provided with one of the elastic film 51 and the insulator film 52, and the first electrode without the elastic film 51 and the insulator film 52 being provided as the diaphragm 50. Only 60 may act as a diaphragm. Further, the actuator 130 itself may substantially serve as a diaphragm.

  The piezoelectric layer 70 is made of an oxide piezoelectric material having a polarization structure, for example, can be made of a perovskite oxide represented by the general formula ABO3, and is a lead-based piezoelectric material containing lead or lead-free non-lead. A piezoelectric material or the like can be used.

  Further, the second electrode 80 that is an individual electrode of the actuator 130 is drawn from the vicinity of the end opposite to the supply communication path 19 and extends to the diaphragm 50. For example, gold ( One end of each lead electrode 90 made of Au) or the like is connected.

  Further, a wiring board 121 which is an example of a flexible wiring board provided with a drive circuit 120 for driving the actuator 130 is connected to the other end of the lead electrode 90. As the wiring substrate 121, a flexible sheet-like substrate such as a COF substrate can be used.

  On one surface of the wiring substrate 121, a second terminal row 123 is formed in which a plurality of second terminals (wiring terminals) 122 that are electrically connected to first terminals 311 of the head substrate 300 described later are arranged in parallel. . A plurality of second terminals 122 of this embodiment are arranged in parallel along the scanning direction X to form a second terminal row 123. Note that the driver circuit 120 is not necessarily provided on the wiring board 121. That is, the wiring board 121 is not limited to the COF board, and may be FFC, FPC, or the like.

  A protective substrate 30 having substantially the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 on the actuator 130 side. The protective substrate 30 has a holding portion 31 that is a space for protecting the actuator 130.

  The holding part 31 has a concave shape that opens to the flow path forming substrate 10 side without penetrating the protective substrate 30 in the gravity direction Z that is the thickness direction. In addition, the holding unit 31 is provided independently for each column configured by the actuators 130 arranged in parallel in the scanning direction X. That is, the holding unit 31 is provided so as to accommodate the rows arranged in the scanning direction X of the actuators 130, and for each row of the actuators 130, that is, two are arranged in the carrying direction Y. Such a holding part 31 should just have the space of the grade which does not inhibit the motion of the actuator 130, and the said space may be sealed or may not be sealed.

  The protective substrate 30 has a through hole 32 penetrating in the gravity direction Z which is the thickness direction. The through hole 32 is provided between the two holding portions 31 arranged in parallel in the transport direction Y in the scanning direction X, which is the direction in which the plurality of actuators 130 are arranged in parallel. That is, the through-hole 32 is an opening having a long side in the direction in which the plurality of actuators 130 are juxtaposed. The other end of the lead electrode 90 extends so as to be exposed in the through hole 32, and the lead electrode 90 and the wiring substrate 121 are electrically connected in the through hole 32.

  As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used. Moreover, the joining method of the flow path forming substrate 10 and the protective substrate 30 is not particularly limited. For example, in the present embodiment, the flow path forming substrate 10 and the protective substrate 30 are joined via an adhesive (not shown). Has been.

  The head unit 2 having such a configuration includes a flow path forming member 40 that defines the common liquid chamber 100 communicating with the plurality of pressure generating chambers 12 together with the head main body 11. The flow path forming member 40 has substantially the same shape as the communication plate 15 described above in a plan view, and is bonded to the protective substrate 30 and is also bonded to the communication plate 15 described above. Specifically, the flow path forming member 40 has a recess 41 having a depth in which the flow path forming substrate 10 and the protective substrate 30 are accommodated on the protective substrate 30 side. The concave portion 41 has an opening area larger than the surface of the protective substrate 30 bonded to the flow path forming substrate 10. The opening surface on the nozzle plate 20 side of the recess 41 is sealed by the communication plate 15 in a state where the flow path forming substrate 10 and the like are accommodated in the recess 41. As a result, the third manifold portion 42 is defined by the flow path forming member 40 and the head body 11 on the outer periphery of the flow path forming substrate 10. The first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15 and the third manifold portion 42 defined by the flow path forming member 40 and the head main body 11 are common to the present embodiment. A liquid chamber 100 is configured.

  That is, the common liquid chamber 100 includes the first manifold portion 17, the second manifold portion 18, and the third manifold portion 42. Further, the common liquid chamber 100 of the present embodiment is disposed on both outer sides of the two rows of pressure generating chambers 12 in the transport direction Y, and two common chambers provided on both outer sides of the two rows of pressure generating chambers 12. The liquid chambers 100 are provided independently so as not to communicate with each other in the head unit 2. That is, one common liquid chamber 100 is provided in communication with each row of pressure generation chambers 12 (rows arranged in parallel in the scanning direction X) of the present embodiment. In other words, a common liquid chamber 100 is provided for each nozzle group. Of course, the two common liquid chambers 100 may communicate with each other.

  As described above, the flow path forming member 40 is a member that forms a flow path (common liquid chamber 100) of ink supplied to the head main body 11, and has an introduction port 44 that communicates with the common liquid chamber 100. . That is, the introduction port 44 is an opening serving as an inlet for introducing the ink supplied to the head body 11 into the common liquid chamber 100.

  The flow path forming member 40 is provided with a connection port 43 that communicates with the through hole 32 of the protective substrate 30 and through which the wiring substrate 121 is inserted. The other end portion of the wiring board 121 extends in the penetrating direction of the through hole 32 and the connection port 43, that is, in the gravitational direction Z and opposite to the ink droplet ejection direction.

  In addition, as a material of such a flow path formation member 40, resin, a metal, etc. can be used, for example. Incidentally, the flow path forming member 40 can be mass-produced at low cost by molding a resin material.

  A compliance substrate 45 is provided on the surface of the communication plate 15 where the first manifold portion 17 and the second manifold portion 18 open. The compliance substrate 45 has substantially the same size as the communication plate 15 described above in a plan view, and is provided with a first exposure opening 45a that exposes the nozzle plate 20. The compliance substrate 45 seals the opening on the liquid ejection surface 20a side of the first manifold portion 17 and the second manifold portion 18 in a state where the nozzle plate 20 is exposed by the first exposed opening portion 45a. That is, the compliance substrate 45 defines a part of the common liquid chamber 100.

  In this embodiment, the compliance substrate 45 includes a sealing film 46 and a fixed substrate 47. The sealing film 46 is made of a flexible film-like thin film (for example, a thin film having a thickness of 20 μm or less formed of polyphenylene sulfide (PPS) or the like), and the fixed substrate 47 is made of stainless steel (SUS) or the like. It is made of a hard material such as metal. Since the region of the fixed substrate 47 that faces the common liquid chamber 100 is an opening 48 that is completely removed in the thickness direction, one surface of the common liquid chamber 100 has a flexible sealing film 46. It becomes the compliance part 49 which is the flexible part sealed only by. In the present embodiment, one compliance unit 49 is provided corresponding to one common liquid chamber 100. That is, in this embodiment, since two common liquid chambers 100 are provided, two compliance portions 49 are provided on both sides in the transport direction Y across the nozzle plate 20.

  In the head unit 2 having such a configuration, when ink is ejected, the ink is taken in through the introduction port 44, and the inside of the flow path is filled with the ink from the common liquid chamber 100 to the nozzle 21. Thereafter, according to a signal from the drive circuit 120, a voltage is applied to each actuator 130 corresponding to the pressure generation chamber 12, so that the diaphragm 50 is bent and deformed together with the actuator 130. As a result, the pressure in the pressure generating chamber 12 increases and ink droplets are ejected from the predetermined nozzle 21.

<Regarding the configuration of the liquid ejecting unit>
Next, the liquid ejecting unit 1 having the head unit 2 will be described in detail.
As shown in FIG. 6, the liquid ejecting unit 1 includes four head units 2, a flow path member 200 that includes the holder member that holds the head unit 2 and supplies ink to the head unit 2, and the flow path member 200. A held head substrate 300 and a wiring substrate 121 which is an example of a flexible wiring substrate are provided.

FIG. 7 is a plan view of the liquid ejecting unit 1 in which the seal member 230 and the upstream flow path member 210 are not shown.
As shown in FIG. 8, the flow path member 200 is disposed between the upstream flow path member 210, the downstream flow path member 220 that is an example of the holder member, and the upstream flow path member 210 and the downstream flow path member 220. And a sealing member 230.

  The upstream flow path member 210 has an upstream flow path 500 that serves as an ink flow path. In the present embodiment, the upstream flow path member 210 is configured by laminating a first upstream flow path member 211, a second upstream flow path member 212, and a third upstream flow path member 213 in the gravity direction Z. . Each of these members is provided with a first upstream flow path 501, a second upstream flow path 502, and a third upstream flow path 503, which are connected to form an upstream flow path 500.

  In addition, the upstream flow path member 210 is not limited to such an aspect, and may be a single member or a plurality of two or more members. Further, the stacking direction of the plurality of members constituting the upstream flow path member 210 is not particularly limited, and may be the scanning direction X and the transport direction Y.

  The first upstream flow path member 211 has a connection part 214 connected to a liquid holding means such as an ink tank or an ink cartridge in which ink (liquid) is held on the side opposite to the downstream flow path member 220. In this embodiment, the connecting portion 214 protrudes in a needle shape. Note that a liquid holding unit such as an ink cartridge may be directly connected to the connection unit 214, or a liquid holding unit such as an ink tank may be connected via a supply pipe such as a tube.

  A first upstream flow path 501 is provided in the first upstream flow path member 211. The first upstream flow path 501 opens at the top surface of the connection portion 214 and extends in the gravitational direction Z according to the position of the second upstream flow path 502 described later, or a direction orthogonal to the gravitational direction Z, that is, It is composed of a flow path or the like extending in a plane including the scanning direction X and the conveyance direction Y. A guide wall 215 (see FIG. 6) for positioning the liquid holding portion is provided around the connection portion 214 of the first upstream flow path member 211.

  The second upstream flow path member 212 has a second upstream flow path 502 that is fixed to the opposite side of the connection portion 214 of the first upstream flow path member 211 and communicates with the first upstream flow path 501. A first liquid reservoir 502 a having an inner diameter wider than that of the second upstream channel 502 is provided on the downstream side of the second upstream channel 502 (on the third upstream channel member 213 side).

  The third upstream flow path member 213 is provided on the opposite side of the second upstream flow path member 212 from the first upstream flow path member 211. The third upstream flow path member 213 is provided with a third upstream flow path 503. The opening part of the third upstream channel 503 on the second upstream channel 502 side is a second liquid reservoir 503a that is widened in accordance with the first liquid reservoir 502a. A filter 216 for removing bubbles and foreign matters contained in the ink is provided at the opening of the second liquid reservoir 503a (between the first liquid reservoir 502a and the second liquid reservoir 503a). As a result, the ink supplied from the second upstream channel 502 (first liquid reservoir 502a) is supplied to the third upstream channel 503 (second liquid reservoir 503a) via the filter 216.

  As the filter 216, for example, a net-like body such as a wire net or a resin net, a porous body, or a metal plate in which fine through holes are formed can be used. Specific examples of the mesh-shaped body include metal mesh filters and metal fibers, for example, SUS fine wires made of felt, or compression sintered metal sintered filters, electroforming metal filters, electron beam processing A metal filter, a laser beam processed metal filter, or the like can be used. In particular, it is preferable that the bubble point pressure (pressure at which the meniscus formed by opening the filter breaks) does not vary, and a filter having a high-definition hole diameter is appropriate. Further, the filter particle size of the filter is preferably smaller than the diameter of the nozzle opening when the nozzle opening is circular, for example, in order to prevent foreign matters in the ink from reaching the nozzle opening.

  When a stainless steel mesh filter is used as the filter 216, in order to prevent foreign matter in the ink from reaching the nozzle opening, the filter particle size of the filter is a nozzle opening (for example, when the nozzle opening is circular, the diameter of the nozzle opening is 20 μm). ) Smaller than the twilled weave (filtering particle size 10 um) is preferable. In this case, the bubble point pressure generated by the ink (surface tension 28 mN / m) (the pressure at which the meniscus formed by the filter opening breaks) is 3 to 5 kPa. It is. Moreover, the bubble point pressure (pressure at which the meniscus formed by the filter opening breaks) generated in the ink when the twill weave (filtering particle size 5 um) is employed is 0 to 15 kPa.

  The third upstream flow path 503 is branched into two on the downstream side (opposite side to the second upstream flow path) from the second liquid reservoir 503a, and the third upstream flow path 503 is the third upstream flow path. The member 213 is opened as a first discharge port 504A and a second discharge port 504B on the surface on the downstream flow path member 220 side. Hereinafter, when the first outlet 504A and the second outlet 504B are not distinguished, they are referred to as outlets 504.

  That is, the upstream flow path 500 corresponding to one connection portion 214 includes a first upstream flow path 501, a second upstream flow path 502, and a third upstream flow path 503, and the upstream flow path 500 is a downstream flow path member. The two outlets 504 (the first outlet 504A and the second outlet 504B) are opened on the 220 side. In other words, the two outlets 504 (the first outlet 504A and the second outlet 504B) are provided in communication with a common flow path.

  A third protrusion 217 that protrudes toward the downstream flow channel member 220 is provided on the downstream flow channel member 220 side of the third upstream flow channel member 213. The third protrusion 217 is provided for each third upstream flow path 503, and the discharge port 504 is opened at the distal end surface of the third protrusion 217.

  The first upstream flow channel member 211, the second upstream flow channel member 212, and the third upstream flow channel member 213 provided with such an upstream flow channel 500 are integrally laminated by, for example, an adhesive or welding. ing. The first upstream flow channel member 211, the second upstream flow channel member 212, and the third upstream flow channel member 213 can be fixed with screws, clamps, or the like. In order to suppress the leakage of ink (liquid) from the connection portion up to 503, it is preferable to join with an adhesive or welding.

  In the present embodiment, four connection portions 214 are provided in one upstream flow path member 210, and four independent upstream flow paths 500 are provided in one upstream flow path member 210. Each upstream flow channel 500 is supplied with ink corresponding to each of the four head units 2. One upstream flow path 500 is branched into two, and communicates with a downstream flow path 600 described later, and is connected to each of the two inlets 44 of the head unit 2.

  In this embodiment, the upstream flow channel 500 is divided into two at the downstream side (downstream flow channel member 220 side) from the filter 216. However, the present invention is not limited to this, and the downstream side from the filter 216. The upstream flow channel 500 may be branched into three or more. One upstream flow channel 500 may not be branched downstream of the filter 216.

  The downstream flow path member 220 is an example of a holder member that has a downstream flow path 600 that is joined to the upstream flow path member 210 and communicates with the upstream flow path 500. The downstream flow path member 220 according to the present embodiment includes a first downstream flow path member 240 that is an example of a first member and a second downstream flow path member 250 that is an example of a second member.

  The downstream flow path member 220 includes a downstream flow path 600 that serves as an ink flow path. The downstream flow path 600 according to the present embodiment includes two types of downstream flow paths 600A and downstream flow paths 600B having different shapes.

  The first downstream flow path member 240 is a member formed in a substantially flat plate shape. The second downstream flow channel member 250 is provided with a first storage portion 251 as a recess on the surface on the upstream flow channel member 210 side and a second storage portion 252 as a recess on the surface opposite to the upstream flow channel member 210. It is a member.

  The 1st accommodating part 251 is taken as the magnitude | size of the grade in which the 1st downstream flow path member 240 is accommodated. Further, the second accommodating portion 252 has a size that accommodates the four head units 2. The second accommodating portion 252 according to the present embodiment can accommodate four head units 2.

  A plurality of first protrusions 241 are formed on the surface of the first downstream flow path member 240 on the upstream flow path member 210 side. Each first protrusion 241 is provided to face the third protrusion 217 provided with the first discharge port 504 </ b> A among the third protrusions 217 provided in the upstream flow path member 210. In the present embodiment, four first protrusions 241 are provided.

  The first downstream flow path member 240 is provided with a first flow path 601 that penetrates in the gravity direction Z and opens at the top surface of the first projection 241 (the surface facing the upstream flow path member 210). Yes. The third protrusion 217 and the first protrusion 241 are joined via the seal member 230, and the first outlet 504A and the first flow path 601 are in communication.

  The first downstream flow path member 240 is formed with a plurality of second through holes 242 penetrating in the gravity direction Z. Each of the second through holes 242 is formed at a position where the second protrusion 253 formed in the second downstream flow path member 250 is inserted. In the present embodiment, four second through holes 242 are provided.

  Further, the first downstream flow path member 240 is formed with a plurality of first insertion holes 243 through which the wiring board 121 electrically connected to the head unit 2 is inserted. Specifically, each first insertion hole 243 penetrates in the gravity direction Z and communicates with the second insertion hole 255 of the second downstream flow path member 250 and the third insertion hole 302 of the head substrate 300. Is formed. In the present embodiment, four first insertion holes 243 are provided corresponding to the respective wiring boards 121 provided in the four head units 2. The first downstream flow path member 240 is provided with a support portion 245 that protrudes toward the head substrate 300 and has a receiving surface.

  A plurality of second protrusions 253 are formed on the bottom surface of the first housing part 251 in the second downstream flow path member 250. Each second protrusion 253 is provided to face the third protrusion 217 provided with the second discharge port 504 </ b> B among the third protrusions 217 provided in the upstream flow path member 210. In the present embodiment, four second protrusions 253 are provided. In addition, the downstream downstream channel member 250 penetrates in the gravity direction Z and is open to the top surface of the second protrusion 253 and the bottom surface of the second storage unit 252 (the surface facing the head unit 2). 600B is provided. The 3rd projection part 217 and the 2nd projection part 253 are joined via seal member 230, and the 2nd discharge port 504B and downstream flow path 600B are connecting.

  A plurality of third flow paths 603 penetrating in the gravity direction Z are formed in the second downstream flow path member 250. Each third flow path 603 is open to the bottom surfaces of the first storage portion 251 and the second storage portion 252. In the present embodiment, four third flow paths 603 are provided.

  A plurality of groove portions 254 that are continuous with the third flow path 603 are formed on the bottom surface of the first housing portion 251 of the second downstream flow path member 250. The groove portion 254 constitutes the second flow channel 602 by being sealed by the first downstream flow channel member 240 housed in the first housing portion 251. That is, the second flow path 602 is a flow path defined by the groove portion 254 and the surface of the first downstream flow path member 240 on the second downstream flow path member 250 side. The second flow path 602 corresponds to a flow path provided between the first member and the second member described in the claims.

  Further, the second downstream flow path member 250 is formed with a plurality of second insertion holes 255 through which the wiring board 121 electrically connected to the head unit 2 is inserted. Specifically, each second insertion hole 255 penetrates in the gravity direction Z and is formed to communicate with the first insertion hole 243 of the first downstream flow path member 240 and the connection port 43 of the head unit 2. . In the present embodiment, four second insertion holes 255 are provided corresponding to the respective wiring boards 121 provided in the four head units 2.

  The downstream flow path 600A is formed by communicating the first flow path 601, the second flow path 602, and the third flow path 603 described above. Here, the second flow path 602 is formed by sealing a groove formed on one surface of the first downstream flow path member 240 with the second downstream flow path member 250. By joining the first downstream flow path member 240 and the second downstream flow path member 250, the second flow path 602 can be easily formed in the downstream flow path member 220.

  The second channel 602 is an example of a channel extending in the horizontal direction. The phrase “the second flow path 602 extends in the horizontal direction” means that a component (vector) in the scanning direction X or the transport direction Y is included in the extending direction of the second flow path 602. Since the second flow path 602 extends in the horizontal direction, the height of the liquid ejecting unit 1 in the gravity direction Z can be reduced. If the second flow path 602 is inclined with respect to the horizontal direction, the height of the liquid ejecting unit 1 is slightly required.

  Incidentally, the extending direction of the second flow path 602 is a direction in which the ink (liquid) in the second flow path 602 flows. Accordingly, the second flow path 602 is also provided in the horizontal direction (direction orthogonal to the gravity direction Z), and intersects the gravity direction Z and the horizontal direction (in-plane direction of the scanning direction X and the conveyance direction Y). Including those provided. In the present embodiment, the first flow path 601 and the third flow path 603 are provided along the gravity direction Z, and the second flow path 602 is provided along the horizontal direction (conveyance direction Y). The first flow path 601 and the third flow path 603 may be provided in a direction crossing the gravity direction Z.

  Of course, the downstream flow path 600A is not limited to this, and a flow path other than the first flow path 601, the second flow path 602, and the third flow path 603 may exist. Further, the downstream flow path 600A is not composed of the first flow path 601, the second flow path 602, and the third flow path 603, but may be composed of a single flow path.

  As described above, the downstream flow path 600B is formed as a through-hole penetrating the second downstream flow path member 250 in the gravity direction Z. Of course, the downstream flow path 600B is not limited to such an embodiment, and may be formed along a direction intersecting the gravitational direction Z, for example, or a plurality of flow paths may be communicated like the downstream flow path 600A. It may be configured.

  One such downstream flow path 600 </ b> A and one downstream flow path 600 </ b> B is formed for each head unit 2. That is, the downstream channel member 220 is provided with a total of four sets of the downstream channel 600A and the downstream channel 600B.

  Of the openings at both ends of the downstream flow path 600A, the opening of the first flow path 601 that communicates with the first discharge port 504A is defined as the first inlet 610, and the opening of the third flow path 603 that opens to the second accommodating portion 252. Is the first outlet 611.

  Of the openings at both ends of the downstream flow path 600B, the opening of the downstream flow path 600B that communicates with the second discharge port 504B is referred to as the second inlet 620, and the opening of the downstream flow path 600B that opens to the second accommodating portion 252 is the first. Two outlets 621 are provided. Hereinafter, when the downstream flow path 600A and the downstream flow path 600B are not distinguished, they are referred to as the downstream flow path 600.

  As shown in FIG. 6, the downstream flow path member 220 (holder member) holds the head unit 2 on the lower side. Specifically, a plurality of (four in this embodiment) head units 2 are accommodated in the second accommodating portion 252 of the downstream flow path member 220.

  As shown in FIG. 8, the head unit 2 is provided with two introduction ports 44. The first outlet 611 and the second outlet 621 of the downstream channel 600 (downstream channel 600A and downstream channel 600B) are provided in the downstream channel member 220 in accordance with the position where each inlet 44 opens. .

  The inlets 44 of the head unit 2 are aligned so as to communicate with the first outlet 611 and the second outlet 621 of the downstream flow path 600 that is opened at the bottom surface of the second housing portion 252. The head unit 2 is fixed to the second housing portion 252 with an adhesive 227 provided around each introduction port 44. In this way, the head unit 2 is fixed to the second housing portion 252, so that the first outlet 611 and the second outlet 621 of the downstream flow path 600 communicate with the inlet 44, and ink is supplied to the head unit 2. It comes to be supplied.

  In the downstream flow path member 220 (holder member), the head substrate 300 is placed on the upper side. Specifically, the head substrate 300 is placed on the surface of the downstream flow channel member 220 on the upstream flow channel member 210 side. The head substrate 300 is a member to which a wiring substrate 121 is connected, and a circuit for controlling the ejecting operation and the like of the liquid ejecting unit 1 and electrical components such as resistors are mounted via the wiring substrate 121.

  As shown in FIG. 6, a plurality of first terminals (electrode terminals) 311 to which the second terminal row 123 of the wiring board 121 is electrically connected are arranged on the surface of the head substrate 300 on the upstream flow path member 210 side. The provided first terminal row 310 is formed. A plurality of first terminals 311 of this embodiment are arranged in parallel along the scanning direction X to form a first terminal row 310. In the present embodiment, the first terminal row 310 is an example of a mounting region that is electrically connected to the wiring board 121.

  The head substrate 300 is formed with a plurality of third insertion holes 302 through which the wiring substrate 121 electrically connected to the head unit 2 is inserted. Specifically, each third insertion hole 302 is formed so as to penetrate in the gravity direction Z and communicate with the first insertion hole 243 of the first downstream flow path member 240. In the present embodiment, four third insertion holes 302 are provided corresponding to the respective wiring boards 121 provided in the four head units 2.

  Further, the head substrate 300 is provided with a third through hole 301 penetrating in the gravity direction Z. The third through hole 301 is inserted through the first protrusion 241 of the first downstream flow path member 240 and the second protrusion 253 of the second downstream flow path member 250. In the present embodiment, a total of eight third through holes 301 are provided so as to face the first protrusion 241 and the second protrusion 253.

  Note that the shape of the third through hole 301 formed in the head substrate 300 is not limited to the above-described mode. For example, a common through hole through which the first protrusion 241 and the second protrusion 253 are inserted may be used as the insertion hole. That is, the head substrate 300 is formed with an insertion hole, a notch or the like so as not to interfere with the connection between the downstream flow path 600 of the downstream flow path member 220 and the upstream flow path 500 of the upstream flow path member 210. Just do it.

  As shown in FIG. 8, a seal member 230 is provided between the head substrate 300 and the upstream flow path member 210. As a material of the seal member 230, a material (elastic material) that is liquid-resistant and elastically deformable with respect to a liquid such as ink used in the liquid ejecting unit 1, for example, rubber or elastomer is used. it can.

  The seal member 230 is a plate-like member in which a communication path 232 that penetrates in the gravity direction Z and a fourth protrusion 231 that protrudes toward the downstream flow path member 220 are formed. In the present embodiment, eight communication paths 232 and fourth protrusions 231 are formed corresponding to each upstream flow path 500 and downstream flow path 600.

  An annular first recess 233 into which the third protrusion 217 is inserted is provided on the upstream flow path member 210 side of the seal member 230. The first recess 233 is provided at a position facing the fourth protrusion 231.

  The fourth protruding portion 231 protrudes toward the downstream flow channel member 220 and is provided at a position facing the first protruding portion 241 and the second protruding portion 253 of the downstream flow channel member 220. A second recess 234 into which the first protrusion 241 and the second protrusion 253 are inserted is provided on the top surface of the fourth protrusion 231 (the surface facing the downstream flow path member 220).

  The communication path 232 passes through the seal member 230 in the gravity direction Z, and has one end opened to the first recess 233 and the other end opened to the second recess 234. Then, a fourth projection is formed between the tip surface of the third projection 217 inserted into the first recess 233 and the tip surfaces of the first projection 241 and the second projection 253 inserted into the second recess 234. The portion 231 is held in a state where a predetermined pressure is applied in the gravity direction Z. Therefore, the upstream flow path 500 and the downstream flow path 600 are communicated in a sealed state via the communication path 232.

  A cover head 400 is attached to the second accommodating portion 252 side (lower side) of the downstream flow path member 220. The cover head 400 is a member that is fixed to the downstream flow path member 220 to which the head unit 2 is fixed, and is provided with a second exposure opening 401 that exposes the nozzle 21. In the present embodiment, the second exposure opening 401 has a size that exposes the nozzle plate 20, that is, substantially the same opening as the first exposure opening 45 a of the compliance substrate 45.

  The cover head 400 is bonded to the surface of the compliance substrate 45 opposite to the communication plate 15, and seals the space on the opposite side of the compliance portion 49 from the flow path (common liquid chamber 100). Thus, by covering the compliance part 49 with the cover head 400, it can suppress that the compliance part 49 is destroyed even if it contacts the medium ST. Further, it is possible to suppress the ink (liquid) from adhering to the compliance portion 49 and to wipe the ink (liquid) adhering to the surface of the cover head 400 with, for example, a wiper blade. It is possible to suppress contamination with attached ink or the like. Although not particularly illustrated, the space between the cover head 400 and the compliance unit 49 is open to the atmosphere. Of course, the cover head 400 may be provided independently for each head unit 2.

<Maintenance device configuration>
Next, the configuration of the maintenance device 710 will be described in detail.
As shown in FIG. 9, the non-printing area RA includes a wiping area WA provided with a wiper unit 750, a receiving area FA provided with a flushing unit 751, and a maintenance area MA provided with a cap unit 752. . That is, in the non-printing area RA, the wiping area WA, the receiving area FA, and the maintenance area MA are located in the wiping area WA, the receiving area FA, and the maintenance area MA from the printing area PA (see FIG. 2) side in the scanning direction X. Arranged in order.

  The wiper unit 750 includes a wiping member 750 a that wipes the liquid ejecting unit 1. The wiping member 750a of the present embodiment is movable and performs a wiping operation with the power of the wiping motor 753. The flushing unit 751 has a liquid receiving portion 751 a that receives the ink droplets ejected by the liquid ejecting portion 1.

  The liquid receiving portion 751a of the present embodiment is constituted by a belt, and moves the belt by the power of the flushing motor 754 at a predetermined time when the amount of ink stain due to the flushing of the belt can be considered to exceed the specified amount. Note that flushing is an operation for forcibly ejecting (discharging) ink droplets from all the nozzles 21 irrespective of printing for the purpose of preventing and eliminating clogging of the nozzles 21 and the like.

  The cap unit 752 can contact the liquid ejecting units 1A and 1B so as to surround the opening of the nozzle 21 when the liquid ejecting units 1A and 1B are located at the home position HP as shown by a two-dot chain line in FIG. Two cap portions 752a. The two cap portions 752a are configured to be movable between a contact position where the capping motor 755 is in contact with the liquid ejecting portion 1 at the home position HP and a retracted position away from the liquid ejecting portion 1. .

  The wiper unit 750 includes a movable casing 759 that can reciprocate on a pair of rails 758 extending along the conveyance direction Y by the power of the wiping motor 753. In the housing 759, a feeding shaft 760 and a winding shaft 761 that are positioned at a predetermined distance in the wiping direction (same as the transport direction Y) are rotatably supported. The feeding shaft 760 supports a feeding roll 763 formed by an unused cloth sheet 762, and the winding shaft 761 supports a winding roll 764 formed by a used cloth sheet 762.

  The cloth sheet 762 positioned between the feeding roll 763 and the take-up roll 764 is wound around the upper surface of the pressing roller 765 that partially protrudes upward from an opening (not shown) at the center of the upper surface of the housing 759 and pressed. A semi-cylindrical (convex) wiping member 750a is formed at a portion wound around the roller 765. The wiping member 750a is biased upward.

  The casing 759 is a wiping direction via a cassette that houses the feeding roll 763 and the take-up roll 764 and a power transmission mechanism (for example, a rack and pinion mechanism) that is guided by the rail 758 and that is not illustrated by the power of the wiping motor 753. It is comprised from the holder which can reciprocately move (direction along the conveyance direction Y in this embodiment). The housing 759 is driven in the transport direction Y between the retracted position shown in FIG. 9 and the wiping position where the wiping member 750a finishes wiping the liquid ejecting unit 1 when the wiping motor 753 is driven in the forward and reverse directions. Move one round trip.

  At this time, when the forward movement of the housing 759 is finished, the power transmission mechanism is switched to a state where the wiping motor 753 and the winding shaft 761 are connected so as to be able to transmit power, and the power when the wiping motor 753 is driven in reverse rotation is switched. A backward movement operation of the housing 759 and a predetermined amount of winding operation of the cloth sheet 762 around the winding roll 764 are performed. The two liquid ejecting units 1A and 1B are sequentially moved with respect to the wiping area WA, and the wiping with respect to the two liquid ejecting units 1A and 1B by one reciprocating movement of the housing 759 is individually moved to the wiping area WA. Done.

  The flushing unit 751 includes a driving roller 766 and a driven roller 767 that are parallel to each other in the transport direction Y, and an endless belt 768 that is wound between the driving roller 766 and the driven roller 767. The belt 768 has a width equal to or greater than eight rows (2 rows × 4 rows) in the scanning direction X, and receives the ink ejected from the nozzles 21 of the liquid ejecting units 1A and 1B. A liquid receiving portion 751a is configured. In this case, the outer peripheral surface of the belt 768 is a liquid receiving surface 769 that receives ink.

  The flushing unit 751 has a moisturizing liquid supply unit (not shown) capable of supplying moisturizing liquid to the liquid receiving surface 769 below the belt 768, and a liquid that scrapes off waste ink and the like adhering to the liquid receiving surface 769 in a moisturizing state. The waste ink received by the liquid receiving surface 769 is removed from the belt 768 by the liquid scraping portion. For this reason, the receiving range of the liquid receiving surface 769 facing the nozzle 21 is updated by the circular movement of the belt 768.

  The cap unit 752 includes two cap portions 752a capable of forming a closed space that is in contact with the two liquid ejecting portions 1A and 1B and surrounds the liquid ejecting surface 20a (see FIG. 3) that is an opening region where the nozzle 21 opens. Have. Each cap unit 752a is moved between a contact position at which the cap unit 752a can contact the liquid ejecting unit 1 and a retracted position away from the liquid ejecting unit 1 by the power of the capping motor 755. Each cap portion 752a includes one suction cap 770 and four moisturizing caps 771. Each of the moisturizing caps 771 controls the drying of the nozzles 21 by performing capping to form a closed space surrounding the nozzle rows NL (see FIG. 3) in contact with the liquid ejecting unit 1.

  The suction cap 770 is connected to the suction pump 773 via the tube 772. Then, the suction pump 773 is driven in a state where the suction cap 770 is in contact with the liquid ejecting unit 1 to form a sealed space, so that the thickened ink is generated from the nozzle 21 by the action of the negative pressure generated in the suction cap 770. So-called suction cleaning is performed in which air bubbles and the like are sucked and discharged together with ink.

  Such suction cleaning is performed for each of the two nozzle rows NL for the liquid ejecting units 1A and 1B. When suction cleaning is performed, the ink droplets discharged from the nozzles 21 adhere to the liquid ejecting unit 1, and therefore, after the suction cleaning is performed, wiping by the wiping member 750a is performed in order to remove the adhered droplets and the like. Preferably it is done. Further, when the wiping member 750a performs wiping, there is a possibility that foreign matter or bubbles adhering to the liquid ejecting unit 1 are pushed into the nozzle 21 to destroy the meniscus or cause a discharge failure. Therefore, it is preferable that after the wiping is performed, the foreign matter mixed in the nozzle 21 is discharged and the ink meniscus in the nozzle 21 is adjusted by performing flushing.

<About the configuration of the fluid ejection device>
Next, the configuration of the fluid ejection device 775 will be described in detail.
As shown in FIG. 10, the fluid ejecting apparatus 775 is configured to eject at least one of air (gas) and second liquid (cleaning liquid) to the liquid ejecting unit 1. The fluid ejecting device 775 can eject the mixed fluid in which the air and the second liquid are mixed by ejecting the air and the second liquid together.

  The second liquid is preferably the same as the main solvent of the ink to be used. In this embodiment, since the water-based resin ink in which the ink solvent is water is employed, pure water is used as the second liquid. For example, when the ink solvent is the solvent, the ink is used as the second liquid. It is preferable to use the same solvent. Moreover, you may use the liquid which contained the preservative in the pure water as a 2nd liquid.

  The preservative contained in the second liquid is preferably the same as the preservative contained in the ink. For example, an aromatic halogen compound (for example, Preventol CMK), methylene dithiocyanate, halogen-containing nitrogen-sulfur compound 1,2-benzisothiazolin-3-one (for example, PROXEL GXL) and the like. When PROXEL is employed as a preservative from the viewpoint of difficulty in foaming, the content of the second liquid is preferably 0.05 mass percent or less.

  The fluid ejection device 775 includes an ejection unit 777, and the ejection unit 777 includes a fluid ejection nozzle 778 having an ejection port 778j that can eject the mixed fluid. The fluid ejecting nozzle 778 is disposed so as to eject the mixed fluid in the ejecting direction F (for example, upward above the liquid ejecting surface a). The fluid ejection nozzle 778 includes a liquid ejection nozzle 780 that ejects the second liquid toward the ejection direction F, and an annular gas ejection nozzle 781 that ejects air toward the ejection direction F and surrounds the liquid ejection nozzle 780. And.

  That is, both the liquid ejection nozzle 780 and the gas ejection nozzle 781 are open toward the ejection direction F. The opening diameter of the liquid ejecting nozzle 780 is preferably sufficiently larger than the opening diameter of the nozzle 21 of the liquid ejecting unit 1 in consideration of ink adhering and solidifying, for example, 0.4 mm or more. In this embodiment, the opening diameter of the liquid jet nozzle 780 is set to 1.1 mm.

  In addition, a so-called external mixing type in which a mixing portion KA in which the second liquid and air are mixed is located outside the fluid ejection nozzle 778 is employed for the fluid ejection nozzle 778 of the present embodiment. Accordingly, the mixing unit KA is configured by a predetermined space adjacent to the opening of the liquid injection nozzle 780 and the opening of the gas injection nozzle 781. A gas supply pipe 783 that forms a gas flow path 783 a for supplying air from the air pump 782 is connected to the fluid ejection nozzle 778. The gas flow path 783 a communicates with the gas injection nozzle 781.

  A pressure adjustment valve 784 that adjusts the pressure of the air supplied from the air pump 782 is provided in the middle of the gas supply pipe 783. In the fluid ejection device 775 of the present embodiment, the pressure of the air supplied from the air pump 782 to the fluid ejection nozzle 778 is set to be 200 kPa or more. An air filter 785 for removing dust and the like in the air supplied to the fluid ejection nozzle 778 is provided at a position between the pressure adjustment valve 784 and the fluid ejection nozzle 778 in the gas supply pipe 783.

  The fluid ejection nozzle 778 is connected to a liquid supply pipe 788 that forms a liquid channel 788a for supplying a second liquid stored in a storage tank 787 as an example of a liquid storage unit. The liquid flow path 788a communicates with the liquid ejection nozzle 780. At the upper end of the storage tank 787, an air release pipe 789 that opens the liquid storage space SK in the storage tank 787 to the atmosphere is provided, and the atmosphere release pipe 789 is provided with a first electromagnetic valve 790 as an example of an on-off valve. Yes.

  Therefore, when the first electromagnetic valve 790 is opened, the liquid storage space SK is in communication with the atmosphere via the atmosphere release pipe 789, while when the first electromagnetic valve 790 is closed, the liquid storage space SK. Is in a non-communication state that does not communicate with the atmosphere. That is, the first electromagnetic valve 790 is configured to be able to switch the liquid storage space SK between a communication state and a non-communication state by opening and closing.

  The storage tank 787 stores the second liquid and is connected via a supply pipe 792 to a cleaning liquid cartridge 791 that is detachably attached to the printer main body 11a (see FIG. 1). A liquid supply pump 793 for supplying the second liquid in the cleaning liquid cartridge 791 to the storage tank 787 is provided in the middle of the supply pipe 792. A second electromagnetic valve 794 for opening and closing the supply pipe 792 is provided at a position between the liquid supply pump 793 and the storage tank 787 in the supply pipe 792.

  As shown in FIGS. 11 and 12, the ejection unit 777 includes a base member 800 having a bottomed substantially rectangular box shape, a support member 801 disposed in the base member 800 and supporting the fluid ejection nozzle 778, and the base member 800. And a rectangular cylindrical case 802 that accommodates the fluid ejection nozzle 778 and the support member 801. The fluid ejection nozzle 778 is fixed to the support member 801, and the support member 801 and the case 802 are configured to be capable of individually reciprocating along the transport direction Y in the base member 800.

  As shown in FIG. 11, the ejection unit 777 includes a cleaning motor 803, a transmission mechanism 804 that transmits the driving force of the cleaning motor 803 to the support member 801, and a side plate 805 that is erected at an end portion on the printing area PA side. It has. The support member 801 is reciprocated along the transport direction Y together with the fluid ejection nozzle 778 when the driving force of the cleaning motor 803 is transmitted via the transmission mechanism 804. In this case, when the case 802 is pressed from the inside by the support member 801, the case 802 is reciprocated along the transport direction Y together with the support member 801.

  A cover member 806 as an example of a mating member that closes the upper end opening of the case 802 is attached to the case 802. A rectangular through-hole 807 extending in the transport direction Y is formed at a position overlapping with a part of the moving region of the fluid ejection nozzle 778 on the upper surface of the cover member 806 in the gravity direction Z. A rectangular frame-shaped lip portion 808 surrounding the through hole 807 is provided on the upper surface of the cover member 806. On the surface of the side plate 805 on the case 802 side, a guide portion (not shown) that guides the case 802 when the case 802 reciprocates along the transport direction Y is provided.

  As shown in FIG. 12, the guide portion (not shown) rises at the position where the case 802 corresponds to the liquid ejecting portions 1 </ b> A and 1 </ b> B, and the two rows of nozzle rows NL where the lip portions 808 are located close to each other. The case 802 is guided so as to come into contact with the liquid ejecting unit 1 in the enclosed state.

  In this embodiment, the distance between the fluid ejecting nozzle 778 and the liquid ejecting unit 1 in the gravity direction Z is set to about 5 mm, and the medium ST and the liquid ejecting surface supported by the support base 712 shown in FIG. It is longer than the distance (about 1 mm) with 20a.

<About the electrical configuration of the liquid ejecting apparatus>
Next, the electrical configuration of the liquid ejecting apparatus 7 will be described.
As illustrated in FIG. 13, the liquid ejecting apparatus 7 includes a control unit 810 that comprehensively controls the liquid ejecting apparatus 7. The control unit 810 is electrically connected to the linear encoder 811. The linear encoder 811 includes a tape-shaped code plate provided on the back side of the carriage 723 shown in FIG. 1 so as to extend along the guide shaft 722, and slits with a constant pitch fixed to the carriage 723 and perforated in the code plate. And a sensor for detecting the light transmitted through.

  The controller 810 inputs a number of pulses proportional to the amount of movement of the printing unit 720 shown in FIG. 1 from the linear encoder 811, and the printing unit 720 determines the number of pulses input from the home position HP (see FIG. 2). The position of the printing unit 720 in the scanning direction X is grasped by adding when leaving and subtracting when approaching the home position HP.

  A rotary encoder 812 is electrically connected to the control unit 810. The rotary encoder 812 includes a disk-shaped code plate attached to the output shaft of the cleaning motor 803 and a sensor that detects light transmitted through slits of a constant pitch perforated in the code plate.

  The control unit 810 inputs a number of pulses proportional to the amount of movement of the support member 801 from the rotary encoder 812, and determines the number of input pulses when the support member 801 leaves the standby position (the position shown in FIG. 15). By adding and subtracting when approaching the standby position, the position of the support member 801 (fluid ejection nozzle 778) in the transport direction Y is grasped.

  The control unit 810 is electrically connected to the actuator 130 via the drive circuit 813 and controls the drive of the actuator 130. The control unit 810 grasps clogging of each nozzle 21 based on the period of residual vibration of the diaphragm 50 driven by the actuator 130.

  The control unit 810 is electrically connected to the cleaning motor 803, the carriage motor 748, the transport motor 749, the wiping motor 753, the flushing motor 754, and the capping motor 755 via the motor drive circuits 814, 815, 816, 817, 818, and 819, respectively. It is connected to the. Then, the control unit 810 drives and controls the motors 803, 748, 749, 753, 754, and 755, respectively.

  The control unit 810 is electrically connected to the suction pump 773, the air pump 782, and the liquid supply pump 793 through pump drive circuits 820, 821, and 822, respectively. Then, the control unit 810 controls the driving of the pumps 773, 782, and 793, respectively. The control unit 810 is electrically connected to the first electromagnetic valve 790 and the second electromagnetic valve 794 via valve drive circuits 823 and 824, respectively. Then, the control unit 810 controls driving of the electromagnetic valves 790 and 794, respectively.

<Maintenance operation by the maintenance device>
Next, the operation of the liquid ejecting apparatus 7 will be described with particular attention paid to the maintenance operation performed on the liquid ejecting unit 1 by the maintenance apparatus 710.

  When print data is input to the control unit 810 through an external device or the like, the control unit 810 drives the carriage motor 748 based on the print data, and the liquid ejecting units 1A and 1B are moved while the printing unit 720 moves in the scanning direction X. Ink droplets are ejected from the nozzles 21 toward the surface of the medium ST. Then, the ejected ink droplets land on the surface of the medium ST, so that an image or the like is printed on the surface of the medium ST.

  During printing of the medium ST, in order to prevent thickening of ink in the nozzles 21 that do not eject ink droplets among all the nozzles 21, at a predetermined time (for example, every elapse of a predetermined time within a range of 10 to 30 seconds). The printing unit 720 moves to the receiving area FA, and performs flushing that ejects and ejects ink droplets from all the nozzles 21.

  When a predetermined suction cleaning condition is satisfied, the control unit 810 controls the carriage motor 748 to move the printing unit 720 to the home position HP and perform suction cleaning. In the suction cleaning, the suction cap 770 is brought into contact with the liquid ejecting portion 1 so as to surround the nozzle row NL, and the suction pump 773 is driven in a state where a sealed space is formed to apply a negative pressure to the suction cap 770. Then, a predetermined amount of ink is sucked from the nozzle 21 to remove thickened ink, bubbles and the like.

  After the completion of the suction cleaning, the control unit 810 moves the printing unit 720 to the wiping area WA and executes wiping to wipe the liquid ejecting unit 1 with the wiping member 750a, so that the liquid ejecting unit is discharged from the nozzle 21. The droplets attached to 1 are removed. Further, after the wiping is performed, the control unit 810 moves the printing unit 720 to the receiving area FA and performs flushing toward the liquid receiving unit 751a, thereby adjusting the meniscus in the nozzle 21.

  Thereafter, the control unit 810 detects clogging of each nozzle 21 based on the period of residual vibration of the diaphragm 50 driven by the actuator 130. Here, the clogging of each nozzle 21 is detected after completion of the suction cleaning, in particular, resin ink containing a synthetic resin that is cured by heating or UV ink that is cured by UV (ultraviolet) irradiation. This is because when used, the nozzle 21 may not be clogged even if suction cleaning is performed. The clogging referred to here is not only the state in which the ink in the nozzle 21 is solidified and clogged, but also the ink is solidified so that a film is stretched on the meniscus of the nozzle 21, the inside of the nozzle 21, and the pressure generation chamber 12. And a state in which the ink in the nozzle communication path 16 cannot be normally ejected (ejected) from the nozzle 21 due to the viscosity increase.

  If clogging of all the nozzles 21 is not detected and the print job is waiting, the control unit 810 moves the printing unit 720 to the printing area PA and prints the medium ST. On the other hand, when the clogged nozzle 21 is detected among all the nozzles 21, the control unit 810 moves the printing unit 720 to the non-printing area LA on the opposite side to the home position HP side in the scanning direction X. Then, the nozzle 21 that is clogged is removed by cleaning the clogged nozzle 21 with the fluid ejecting device 775.

  When the fluid ejecting device 775 performs nozzle cleaning, these positions are aligned so that the clogged nozzle 21 and the fluid ejecting nozzle 778 face each other in the gravity direction Z. In this case, the clogged nozzle 21 and the fluid ejection nozzle 778 are aligned in the scanning direction X (the direction orthogonal to the direction in which the nozzle row NL extends) by moving the printing unit 720, and the clogged nozzle. 21 and the fluid ejection nozzle 778 are aligned in the transport direction Y (the direction in which the nozzle row NL extends) by moving the fluid ejection nozzle 778.

  Specifically, when the clogged nozzle 21 is in the liquid ejecting portion 1A, the lip portion 808 is clogged after the alignment of the printing portion 720 in the scanning direction X as shown in FIG. The case 802 is moved via the support member 801 so as to come into contact with the liquid ejection surface 20a while surrounding the nozzle row NL including the nozzles 21. Subsequently, the fluid ejecting nozzle 778 is moved via the support member 801 so that the liquid ejecting nozzle 780 of the fluid ejecting nozzle 778 faces the clogged nozzle 21, and the position of the fluid ejecting nozzle 778 in the transport direction Y is adjusted.

  At this time, in a normal state before the mixed fluid is ejected from the fluid ejecting nozzle 778, the first electromagnetic valve 790 is opened, the liquid containing space SK is in communication with the atmosphere, and the second electromagnetic valve 794 is The valve is closed.

  In this state, as shown in FIG. 10, the height H of the gas-liquid interface KK of the second liquid in the liquid flow path 788a is −100 to −− when the height of the tip of the fluid ejection nozzle 778 is zero. It is preferably set to be 1000 mm. In the present embodiment, the height H when the height of the tip of the fluid ejection nozzle 778 is set to 0 is set to −150 mm.

  10 and 12, when the air pump 782 is driven to supply air to the fluid ejection nozzle 778, air is ejected from the gas ejection nozzle 781. The second liquid in the liquid flow path 788a is sucked up by the negative pressure generated by the jetting of air and jetted from the liquid jet nozzle 780. As a result, air and the second liquid are mixed in the mixing unit KA to generate a mixed fluid, and the mixed fluid is ejected onto a partial region of the liquid ejection surface 20a including the clogged nozzle 21.

  The mixed fluid has a droplet shape smaller than the opening of the nozzle 21 (for example, when the nozzle opening is circular and the shape of the droplet is spherical, the diameter is 20 μm or less smaller than the nozzle opening diameter). A large number of second liquids (this small-diameter second liquid droplet is referred to as a small droplet DS, see FIG. 16), and the ejection speed of the mixed fluid from the fluid ejection nozzle 778 at this time is 40 m / sec or more. It is set to be. The kinetic energy of the small droplet DS can destroy the film-like ink solidified at the gas-liquid interface to the extent that it cannot be destroyed by the energy transmitted to the gas-liquid interface in the nozzle 21 by the ink ejection operation or flushing operation during printing. It is preferably equal to or greater than the kinetic energy.

  That is, the product of the mass of the small droplet DS of the second liquid ejected from the ejection port 778 j toward the nozzle 21 by the fluid ejecting device 775 and the square of the flying speed at the opening position of the nozzle 21 of the small droplet DS. The mass of the ink droplet ejected from the opening of the nozzle 21 is set to be larger than the product of the square of the flying speed of the ink droplet.

  Further, the ejection of the mixed fluid including the small droplet DS of the fluid ejecting device 775 to the clogged nozzle 21 (opening region where the nozzle 21 opens) causes the ink in the pressure generation chamber 12 communicating with the clogged nozzle 21 to be ejected. The pressure generation chamber 12 and the actuator 130 corresponding to the pressure generation chamber 12 are preferably pressed in a state of being pressurized by the vibration of the diaphragm 50. Then, when the mixed fluid is ejected from the fluid ejection nozzle 778 to the clogged nozzle 21, a droplet-shaped second liquid smaller than the opening of the nozzle 21 in the mixed fluid enters the nozzle 21 through the opening of the nozzle 21. Then it collides with the clogged part.

  That is, the droplet-shaped second liquid smaller than the opening of the nozzle 21 collides with the ink solidified in the nozzle 21. At this time, the hardened ink is destroyed by the impact on the hardened ink by the second liquid, and the clogging of the nozzle 21 is eliminated. At this time, since the ink in the pressure generation chamber 12 communicating with the nozzle 21 in which the clogging has been eliminated is pressurized, the mixed fluid that has entered the nozzle 21 passes through the pressure generation chamber 12 to become a liquid. It is suppressed that it approachs into the back in 1 A of injection parts.

  When stopping the ejection of the mixed fluid from the fluid ejecting nozzle 778, first, the first electromagnetic valve 790 is closed while the mixed fluid is ejected from the fluid ejecting nozzle 778. The SK is switched from a communication state communicating with the atmosphere to a non-communication state not communicating with the atmosphere. Then, since the liquid containing space SK becomes negative pressure, the second liquid ejected from the liquid ejecting nozzle 780 is drawn into the liquid flow path 788a by the action of the negative pressure.

  Thereby, the gas-liquid interface KK (the water head surface of the storage tank 787) of the second liquid in the liquid channel 788a is positioned on the lower side (storage tank 787 side) than the mixing unit KA. When the air pump 782 is stopped, air is not jetted from the gas jet nozzle 781. In this case, the air pump 782 is stopped in a state where the gas-liquid interface KK of the second liquid in the liquid channel 788a is positioned below the mixing unit KA, so that the second liquid in the liquid channel 788a is mixed with the mixing unit. The entry into the gas injection nozzle 781 beyond KA is suppressed.

  Further, in this case, even after the supply of air from the air pump 782 to the gas injection nozzle 781 via the liquid channel 788a is stopped, the closed state of the first electromagnetic valve 790 is maintained, and the liquid storage space SK is not in communication. Is maintained. Note that unnecessary second liquid after cleaning the nozzle 21 and unnecessary ink washed away from the nozzle 21 flow down from the case 802 into the base member 800 and the waste liquid port (not shown) of the base member 800. To a waste liquid tank (not shown).

  Further, when the clogged nozzle 21 is also present in the liquid ejecting section 1B, as shown in FIG. 14, the lip section 808 is clogged in the liquid ejecting section 1B as in the case of the liquid ejecting section 1A. The case 802 is moved via the support member 801 so as to come into contact with the liquid ejection surface 20a while surrounding the nozzle row NL including the nozzles 21. Then, similarly to the case of the liquid ejecting unit 1A, the mixed fluid is ejected to the clogged nozzle 21 of the liquid ejecting unit 1B with the first electromagnetic valve 790 opened to eliminate the clogging of the nozzle 21. To do.

  Note that the ejection of the mixed fluid from the fluid ejecting nozzle 778 to the liquid ejecting units 1A and 1B including the clogged nozzle 21 may be performed a plurality of times at time intervals. In this case, the time interval may or may not be constant. In this way, even when the mixed fluid ejected to the liquid ejecting portions 1A and 1B becomes a foam and closes the opening of the nozzle 21, the foam that closes the opening of the nozzle 21 while the ejection of the mixed fluid is stopped. The mixed fluid returns to the form of droplets. For this reason, the liquid droplets in the mixed fluid ejected later to the liquid ejecting units 1A and 1B by the mixed fluid that has been first ejected to the liquid ejecting units 1A and 1B and formed into bubbles to block the opening of the nozzle 21 are used. It is possible to prevent the entry into the nozzle 21 from being blocked. If pure water containing no preservative is used as the second liquid, such foaming can be suppressed.

  As shown in FIG. 15, after the fluid ejecting device 775 finishes cleaning the clogged nozzles 21 of the liquid ejecting units 1 </ b> A and 1 </ b> B, the support member is in a state where the mixed fluid is ejected from the fluid ejecting nozzle 778. 801 is moved to the standby position, and the fluid ejection nozzle 778 is opposed to a position that does not correspond to the through hole 807 in the upper wall of the cover member 806. At this time, a slight gap is formed between the fluid ejection nozzle 778 and the upper wall of the cover member 806.

  Then, the air injected from the annular gas injection nozzle 781 surrounding the liquid injection nozzle 780 collides with the upper wall of the cover member 806 and flows along the upper wall, and is injected from the annular gas injection nozzle 781. The pressure inside the air, that is, the upper side of the liquid jet nozzle 780 rises. And the 2nd liquid in the liquid flow path 788a is pressed toward the downward direction (storage tank 787 side) by the pressure which rose above this liquid injection nozzle 780. FIG. That is, the gas-liquid interface KK of the second liquid in the liquid channel 788a is pushed down far below the mixing portion KA.

  When the air pump 782 is stopped in this state, air is not jetted from the gas jet nozzle 781. In this case, the air pump 782 is stopped in a state where the gas-liquid interface KK of the second liquid in the liquid channel 788a is positioned below the mixing unit KA, so that the second liquid in the liquid channel 788a is mixed with the mixing unit. The entry into the gas injection nozzle 781 beyond KA is suppressed.

  Thereafter, the printing unit 720 is moved to the home position HP side, and suction cleaning and flushing for discharging ink from the openings of the respective nozzles 21 of the liquid ejecting units 1A and 1B are performed, so that the inside of the liquid ejecting units 1A and 1B is performed. The remaining second liquid or bubbles are removed. The suction cleaning and flushing at this time may be light and have a small ink discharge amount (consumption amount). The reason is that the jet of the mixed fluid to the clogged nozzle 21 is performed in a state where the ink in the pressure generating chamber 12 communicating with the clogged nozzle 21 is pressurized as described above. This is because the entry (reverse flow) into the interior of the liquid ejecting units 1A and 1B via the generation chamber 12 is suppressed.

(Second Embodiment)
Next, a second embodiment of the liquid ejecting apparatus will be described with reference to the drawings.
In the second embodiment, components having the same reference numerals as those in the first embodiment have the same configuration as those in the first embodiment, and thus the description thereof will be omitted. In the following, description will be made focusing on differences from the first embodiment. Do.

  As shown in FIG. 16, the fluid ejecting apparatus 775 </ b> D included in the liquid ejecting apparatus of the present embodiment is configured to be able to change the direction in which the fluid ejecting nozzle 778 ejects fluid. Here, the position of the fluid ejection nozzle 778 when the fluid is ejected in the first ejection direction S1 substantially orthogonal to the opening surface (liquid ejection surface 20a) where the nozzle 21 opens is referred to as a first position P1. The position of the fluid ejection nozzle 778 when ejecting fluid in the second ejection direction S2 that obliquely intersects the liquid ejection surface 20a is referred to as a second position P2, and is a first position that is parallel to the liquid ejection surface 20a. The position of the fluid ejection nozzle 778 when ejecting fluid in the three ejection directions S3 is referred to as a third position P3.

  In the fluid ejecting apparatus 775D, a liquid tank 832 is connected to a liquid supply pipe 788 that supplies the second liquid to the fluid ejecting nozzle 778 via a supply pipe 831. The liquid tank 832 stores a surfactant. The supply pipe 831 is in communication with the liquid tank 832 and the liquid supply pipe 788 when the supply pipe 831 is in an open state, and is not in communication with the liquid tank 832 and the liquid supply pipe 788 when in a closed state. An opening / closing valve 833 is provided. When the fluid mixture is ejected from the fluid ejection nozzle 778 when the on-off valve 833 is open, the surfactant in the liquid tank 832 is sucked out by the negative pressure generated by the ejection and mixed with the second liquid. Is done. That is, in the fluid ejecting apparatus 775D, by opening the on-off valve 833, the fluid ejecting nozzle 778 ejects a mixed fluid of gas, the second liquid, and the surfactant.

  Furthermore, the liquid ejecting apparatus according to the present embodiment includes a fluid ejecting apparatus 775B separately from the fluid ejecting apparatus 775D. The fluid ejection device 775B includes an air pump 782B, a gas supply pipe 783B whose downstream end is connected to the air pump 782B, a storage tank 787B, a liquid supply pipe 788B whose downstream end is connected to the storage tank 787B, and a gas supply pipe 783B. And a fluid ejection nozzle 778B to which the upstream ends of the liquid supply pipes 788B are respectively connected. And the 3rd liquid containing a liquid repellent component is stored in the storage tank 787B of the fluid ejecting apparatus 775B.

  The fluid ejecting device 775B only needs to be able to eject a fluid containing the third liquid containing the liquid repellent component, and may adopt the same configuration as the fluid ejecting device 775 of the first embodiment. The part may be changed. For example, the fluid ejecting device 775B is disposed in the non-printing area LA or the non-printing area RA, and is capable of ejecting fluid in the second ejecting direction S2 that obliquely intersects the liquid ejecting surface 20a. Is arranged at the second position P2.

<Maintenance operation by fluid ejection device>
Next, the operation of the liquid ejecting apparatus will be described by focusing on the maintenance operation performed on the liquid ejecting unit 1 by the maintenance device 710.

  The fluid ejecting device 775D selectively selects the first mode nozzle cleaning, the second mode liquid ejection surface cleaning, the third mode gas spray, the fourth mode bubble adhesion, or the sixth mode fluid injection according to the purpose. To run. Further, the fluid ejecting apparatus 775B executes the liquid repellent process in the fifth mode at a predetermined timing.

  As shown in FIG. 17, in the first mode nozzle cleaning, as described in detail in the first embodiment, an opening region (liquid ejection surface) where the nozzles 21 are opened for the purpose of eliminating clogging of the nozzles 21. 20a), the fluid ejection nozzle 778 performs a first fluid ejection that ejects a fluid containing a small droplet DS of the second liquid that is smaller than the opening of the nozzle 21. That is, in the first mode, the fluid injection nozzle 778 is disposed at the first position P1, the on-off valve 833 is closed, and the mixed fluid of the second liquid and gas is supplied to the specific nozzle 21 that is clogged as a target. High-speed and high-pressure injection is performed for a short time in the first injection direction S1.

  Next, in the liquid ejection surface cleaning in the second mode, for the purpose of cleaning the liquid ejection surface 20a, the fluid ejection nozzle 778 is smaller than the small droplet DS with respect to the liquid ejection surface 20a of the liquid ejection unit 1. A second fluid ejection is performed to eject a fluid containing a large droplet DL of a second liquid having a large (when the droplet is spherical). Note that the small droplet DS has a smaller droplet diameter than the ink droplet DM and the large droplet DL has an ink droplet compared to the ink droplet DM having the maximum diameter (when the droplet is spherical) ejected from the nozzle 21. Droplet diameter is larger than DM.

  In the second mode, the fluid ejecting nozzle 778 is disposed at the second position P2, the on-off valve 833 is closed, and the portion of the liquid ejecting surface 20a where the nozzle 21 is not opened is used as a target to mix the fluid mixture of the second liquid and gas. Injection is performed for a predetermined time in the second injection direction S2 at a lower speed and lower pressure than in the first mode.

  That is, the direction in which the fluid ejection device 775D ejects fluid from the ejection port 778j in the first fluid ejection is the first ejection direction S1, and the direction in which the fluid ejection device 775D ejects fluid from the ejection port 778j in the second fluid ejection is the first direction. In the case of the two ejection directions S2, it is preferable that the intersection angle of the second ejection direction S2 with respect to the liquid ejection surface 20a is smaller than the intersection angle of the first ejection direction S1 with respect to the liquid ejection surface 20a. In this way, the fluid ejected by the fluid ejecting nozzle 778 is unlikely to enter the nozzle 21, so the ink meniscus formed in the nozzle 21 is unlikely to break.

  In addition, when the meniscus of the ink formed in the nozzle 21 is broken or disturbed, the meniscus can be adjusted by performing flushing or the like. However, it takes time to adjust the meniscus or consumes ink. Therefore, it is desirable that the meniscus is not destroyed or disturbed by the maintenance operation.

  In the second fluid ejection (liquid ejection surface cleaning), in the second ejection direction S2 in which the fluid ejection device 775D ejects fluid from the ejection port 778j, the distance from the ejection port 778j to the liquid ejection surface 20a is set to the first fluid ejection. If it is made longer than when it is performed, the flying speed of the droplet when it reaches the liquid ejection surface 20a can be reduced. This is preferable because even if the fluid ejected by the fluid ejecting nozzle 778 enters the nozzle 21, the meniscus of the ink formed in the nozzle 21 is not easily broken.

  Here, when an adhering matter such as ink adhering to the liquid ejecting surface 20a is solidified, if the wiping member 750a wipes the liquid ejecting surface 20a, the solidified product comes into sliding contact with the liquid ejecting surface 20a. There is. The liquid ejecting surface 20a is often subjected to a liquid repellent treatment for improving the liquid repellency, such as applying a liquid repellent to form a liquid repellent film in order to suppress adhesion of ink droplets. For this reason, when the wiping member 750a wipes the liquid ejection surface 20a to which the solidified material has adhered, the solidified material may be dragged and the liquid repellent film may be damaged, resulting in a decrease in the liquid repellent effect. In that respect, in the second mode maintenance performed by the fluid ejecting apparatus 775D, the liquid ejecting surface 20a is cleaned with the second liquid, so that the foreign matter (ink) adhered to the liquid ejecting surface 20a without damaging the liquid repellent film. And dust) can be removed.

  Further, when the liquid ejecting surface 20a is wiped with the wiping member 750a, foreign matter or bubbles adhering to the liquid ejecting surface 20a are pushed into the nozzle 21 and, on the contrary, a droplet ejection failure may occur. In contrast, when the second liquid is sprayed onto the liquid ejection surface 20a for cleaning, it is preferable because no foreign matter is pushed into the nozzle 21.

  The wiping by the wiping member 750a may be performed in a state where the second liquid ejected by the fluid ejection nozzle 778 by the first fluid ejection or the like is attached to the liquid ejection surface 20a. That is, as a maintenance operation, the fluid ejecting device 775D performs fluid ejection on the opening region (liquid ejecting surface 20a) where the nozzle 21 opens in the liquid ejecting unit 1 to attach the second liquid, and then the second liquid. The opening area is wiped by the wiping member 750a wetted by the contact with. According to this configuration, the dirt adhering to the liquid ejection surface 20a is easily melted and removed by the second liquid, and the frictional resistance of the wiping member 750a to the liquid ejection surface 20a is reduced, so that the liquid-repellent film is not easily damaged. Become. At the time of this wiping, the second liquid only needs to adhere to the liquid ejecting unit 1 or the wiping member 750a. Therefore, the fluid ejecting devices 775 and 775D are not limited to the second fluid ejecting, and the fluid ejecting devices 775 and 775D perform the liquid ejecting unit 1 or wiping. What is necessary is just to inject the 2nd liquid or the mixed fluid containing a 2nd liquid toward the member 750a.

  In this case, the fluid ejecting nozzle 778 may eject a fluid containing the second liquid in a non-opening region (for example, a portion of the cover head 400) that does not include the opening region (the liquid ejecting surface 20a). That is, as a maintenance operation, after the fluid ejecting device 775D performs fluid ejection such as second fluid ejection on the non-opening region to attach the second liquid to the liquid ejecting unit 1, the wiping member 750a is the second fluid. The wiping member 750a, which is in contact with the wet non-opening area and is wetted with the second fluid by the contact, wipes the open area. In this way, if the fluid is ejected while avoiding the opening region where the nozzle 21 is opened, the meniscus is prevented from being destroyed by the fluid ejected by the fluid ejecting nozzle 778 in order to wet the liquid ejecting unit 1, which is preferable. .

  Next, in the third mode gas spraying, the liquid ejecting surface 20a of the liquid ejecting unit 1 is removed for the purpose of removing foreign matters (particularly, ink droplets and dust that have not solidified) attached to the liquid ejecting surface 20a. The fluid ejection nozzle 778 ejects only gas. That is, the fluid ejecting device 775D can selectively eject three types of gas, the second liquid, or a mixed fluid of the gas and the second liquid from the ejection port 778j. The foreign matter adhering to the surface 20a is blown away.

  When the direction in which the fluid ejection device 775D ejects gas from the ejection port 778j in the third mode is the gas ejection direction (third ejection direction S3), the angle θ of the third ejection direction S3 with respect to the liquid ejection surface 20a is 0 ° ≦ It is preferable that θ <90 °. In addition, when the angle θ in the third ejection direction S3 with respect to the liquid ejection surface 20a is small (for example, θ = 0 °) and there is little possibility that the ejected gas disturbs the meniscus of the nozzle 21, the gas is ejected at high speed and high pressure. However, since the removal efficiency of a foreign material is high, it is preferable.

  That is, if the gas ejection direction from the fluid ejection nozzle 778 is the third ejection direction S3, the gas ejected by the fluid ejection nozzle 778 is unlikely to enter the nozzle 21, so the ink meniscus formed in the nozzle 21 is reduced. It is preferable in that it is not easily broken. In the third mode, since the object does not slide on the liquid ejection surface 20a, foreign matters (ink, dust, etc.) attached to the liquid ejection surface 20a by air blowing are removed without damaging the liquid repellent film. It becomes possible.

  Further, the removal of the foreign matter by gas injection can be performed in a shorter time than the wiping performed by moving the wiping member 750a, and therefore, for example, the liquid ejecting unit 1 is periodically removed during the printing operation in the printing area PA. It is possible to perform maintenance that moves to the printing area LA and blows off the ink droplets and the like adhering to the liquid ejecting surface 20a with gas. In addition, in the case of gas injection, it is possible to remove foreign matters attached to a portion where the wiping member 750a cannot contact (for example, a step portion or a gap portion between the cover head 400 and the liquid ejection surface 20a).

  Furthermore, when the gas ejection direction (third ejection direction S3) is along the direction in which the nozzle row NL extends, the nozzle 21 in the adjacent row from which the blown ink (first liquid) ejects ink of another color. This is preferable because it is possible to avoid mixing and mixing colors.

  Next, in the fourth mode of bubble adhesion, the fluid ejection nozzle 778 moves the gas, the second liquid, and the surfactant in the second ejection direction S <b> 2 for the purpose of adhering the foam-like second liquid to the liquid ejection unit 1. The mixed fluid is ejected. In the fourth mode, the fluid ejection nozzle 778 is disposed at the first position P1 and the on-off valve 833 is opened to mix the surfactant with the second liquid ejected from the fluid ejection nozzle 778, and in the first ejection direction S1. By causing the ejected fluid to collide with the liquid ejecting surface 20a or the non-opening region (for example, a portion of the cover head 400) for a predetermined time, the second liquid is bubbled. In the fourth mode, foaming of the liquid is promoted by mixing the surfactant with the second liquid ejected from the fluid ejection nozzle 778.

  The mixing ratio of the second liquid and the surfactant can be adjusted by changing the water head difference between the second liquid in the storage tank 787 and the surfactant in the liquid tank 832. Further, in the fourth mode, as in the second mode, when the fluid containing the large liquid droplet DL of the second liquid having the smallest droplet diameter larger than the small liquid droplet DS is ejected at a lower speed and lower pressure than in the first mode, the nozzle This is preferable because the meniscus 21 is hardly disturbed. Further, in the fourth mode, the second liquid can be efficiently bubbled by continuing the ejection of the fluid containing the second liquid for a longer time than the fluid ejection as the nozzle cleaning in the first mode. .

  Also in the fluid ejecting apparatus 775 of the first embodiment, when a liquid in which pure water contains a preservative is used as the second liquid, the liquid ejecting unit 1 is operated by the action of components contained in the preservative. The second liquid that has collided with the liquid may become foamy. Therefore, in such a case, it is not necessary to mix a surfactant with the second liquid to be ejected.

  Then, as shown in FIG. 18, after the fluid ejecting device 775D attaches the bubble BU (foam-like second liquid) to the liquid ejecting unit 1, the wiping member 750a or the wiping member 750B is applied to the foam-like second liquid. And the wiping member 750B wipes the area to be wiped. In other words, the fluid ejecting device 775D functions as a liquid adhering device that causes the foam-like second liquid to adhere to the liquid ejecting unit 1. This is preferable because the friction resistance when the wiping member 750a is in sliding contact with the liquid ejection surface 20a is reduced by the bubble BU, and the liquid-repellent film is hardly damaged. In the present embodiment, a plate member that can be elastically deformed is illustrated as the wiping member 750B that performs wiping, but the same is true for the wiping member 750a made of the cloth sheet shown in the first embodiment. The effect can be obtained.

  Assuming that a portion to be wiped by the wiping member 750B of the liquid ejecting unit 1 is a region to be wiped, the region to be wiped includes an opening region (liquid ejecting surface 20a) where the nozzle 21 opens in the liquid ejecting unit 1 and an outside of the opening region including And a non-opening area (cover head 400) located in the area. That is, it is preferable that the wiping member 750B wipes not only the liquid ejection surface 20a but also the portion of the cover head 400 on the outer side. The area where the fluid ejection device 775D adheres the bubble BU (foam-like second liquid) before wiping may be an open area, a non-open area, or both areas.

  By the way, as shown in FIG. 19, when capping is performed by contacting the moisture retention cap 771 or the suction cap 770 with the cover head 400 that is a non-opening region, when the caps 770 and 771 are in contact with the liquid ejecting unit 1. In addition, the liquid adhering to the liquid ejecting unit 1 sometimes collects in an annular contact area where the caps 770 and 771 come into contact.

  Then, after the caps 770 and 771 are separated from the liquid ejecting unit 1 due to the release of capping, contact marks (also referred to as lip marks) of the caps 770 and 771 may remain in the contact area of the liquid ejecting unit 1. Therefore, when the wiping area includes a contact area where the caps 770 and 771 come into contact with each other when the capping is performed, and the fluid ejection device 775D attaches the bubble BU (foam-like second liquid) to the contact area, wiping is performed. This is preferable because the trace of contact can be removed.

  In addition, as shown in FIG. 19, the fluid ejecting apparatus 775 </ b> D has the second liquid droplet or bubble BU attached to the liquid ejecting unit 1 by ejecting the mixed fluid in the first, second, or fourth mode. The capping may be performed with the moisturizing cap 771 in contact with the liquid ejecting unit 1 so as to include the attached second liquid in the closed space. In this way, the humidity of the sealed space can be kept high by the second liquid accommodated in the sealed space formed by the moisturizing cap 771, so that the moisturizing effect of the nozzle 21 can be enhanced and the moisturizing time can be lengthened. It becomes possible to do.

  In this case, the fluid ejecting apparatus 775D functions as a liquid attaching apparatus that attaches the second liquid to the liquid ejecting unit 1. In the fluid ejecting apparatus 775D, by mixing and injecting a gas with the second liquid, the droplet diameter of the second liquid can be reduced, the flying speed of the droplet or the pressure of the ejection can be increased. it can. Therefore, when the fluid ejecting apparatus 775D is used for the purpose of adhering the second liquid to the liquid ejecting unit 1, it is not necessary to mix gas with the fluid to be ejected, and the second liquid is used as droplets to fly. You don't have to.

  Here, if the fluid ejected by the fluid ejecting device 775D collides with the liquid ejecting unit 1 at an angle close to a right angle, the fluid ejecting device 775D collides with the liquid ejecting unit 1 and is likely to be scattered around. In that regard, by reducing the crossing angle between the fluid ejection direction F and the liquid ejecting unit 1, scattering when the fluid contacts the liquid ejecting unit 1 is suppressed, and the second liquid is efficiently supplied to the liquid ejecting unit 1. Can be attached to. Therefore, it is preferable to eject the fluid in the second ejection direction S <b> 2 in order to attach the droplet of the second liquid to the liquid ejecting unit 1. On the other hand, in order to foam the second liquid in the liquid ejecting unit 1, it is preferable to eject the mixed fluid in the first ejecting direction S1 in a state where the gas is included in the second liquid.

  In addition, as shown in FIG. 19, when the second liquid is attached to the liquid ejecting unit 1 prior to capping by the moisturizing cap 771 coming into contact with the cover head 400 that is a non-opening region, It is preferable that the fluid ejecting device 775D eject the second liquid toward the liquid because the meniscus of the nozzle 21 is not broken by the ejected second liquid. On the other hand, if the second liquid is caused to adhere to the liquid ejection surface 20a by the ejection of the fluid ejection device 775D, the second liquid can be present at a position closer to the nozzle 21, so that the moisturizing effect can be enhanced.

  Further, after the wiping member 750a or the wiping member 750B performs wiping to clean the liquid ejecting unit 1 after the first fluid ejecting by the fluid ejecting device 775D, the second fluid ejecting or the like of the fluid ejecting device 775D is performed. It is preferable that the moisturizing cap 771 performs capping when the second liquid adheres to the liquid ejecting unit 1 by execution. That is, by removing the foreign matter adhering to the liquid ejecting unit 1 by performing wiping in a state wetted with the second liquid, the foreign matter adhering to the liquid ejecting unit 1 during capping is performed. Can be prevented from sticking.

  As shown in FIG. 20, when the foam-like second liquid is attached at a position close to the nozzle 21, the second liquid film Me is formed on the meniscus surface Sf of the nozzle 21 after the foam BU disappears. The film Me functions as an anti-drying film. Therefore, when capping is performed for a long time or when the environmental temperature is high, capping is preferably performed with the foam-like second liquid attached to the liquid ejection surface 20a. In addition, when capping is performed for a long period of time, if the bubble BU that is generated by mixing a surfactant with the second liquid is adhered, the bubble BU is not easily broken by the action of the surfactant. The two liquid bubbles BU can be present near the nozzle 21 for a longer time.

  Further, as shown in FIG. 19, if an absorbent 774 capable of absorbing and holding a liquid is accommodated in the moisturizing cap 771, the second liquid droplets and bubbles BU adhering to the liquid ejecting unit 1 are transferred to the moisturizing cap. Even when the lip portion or side wall of 771 falls down, the second liquid that has fallen down can be absorbed by the absorbent 774 and held.

  Further, at the time of capping, a portion (for example, of the cover head 400) surrounded by the moisture retention cap 771 of the liquid ejecting unit 1 so that the second liquid adhering to the liquid ejecting unit 1 is retained in the liquid ejecting unit 1 for as long as possible. A groove or a recess may be formed in the portion or the like. If the second liquid adhering to the liquid ejecting unit 1 is held in a position close to the nozzle 21 in this way, the nozzle 21 can be efficiently moisturized.

  Furthermore, the liquid ejecting surface 20a preferably has high liquid repellency in order to suppress the adhesion and solidification of ink droplets, but the liquid repellency of the cover head 400 and the like located around the liquid ejecting surface 20a is made lower than that of the liquid ejecting surface 20a. In this case, it is possible to hold the second liquid for moisture retention in the cover head 400 while suppressing the adhesion of droplets to the liquid ejection surface 20a.

  In order to enhance the moisturizing effect, capping may be performed after ink (waste ink) is put into the moisturizing cap 771 by flushing or the like. Also in this case, drying of the nozzle 21 opening in the moisturizing cap 771 is suppressed by evaporation or volatilization of a dispersion medium or a solvent (for example, water or the like) contained in the ink or the like. In addition, you may make it provide separately the roller etc. which adhere the liquid for moisture retention to the liquid injection part 1. FIG.

  Further, when capping is performed by the suction cap 770 coming into contact with the cover head 400, it is preferable that the liquid adhering to the liquid ejecting unit 1 after the suction cleaning immediately moves to the suction cap 770 side. Therefore, in particular, the lip portion of the suction cap 770 that contacts the cover head 400 is preferably set so that the liquid repellency is lower than that of the cover head 400.

  Next, in the liquid repellent treatment in the fifth mode, when the liquid repellent film is damaged, as a maintenance operation for recovering the liquid repellent performance of the liquid ejecting surface 20a, the fluid ejecting device 775B performs the liquid ejecting surface 20a. On the other hand, a fluid containing a third liquid droplet having a minimum droplet diameter larger than that of the small droplet DS is ejected in the second ejection direction S2. At this time, the third liquid droplets can be diffused over a wide range by ejecting the third liquid together with the gas. Alternatively, after the third liquid droplet is attached to the liquid ejecting surface 20a, wiping may be performed so that the third liquid is uniformly spread over the entire liquid ejecting surface 20a.

  Next, the fluid injection maintenance in the sixth mode includes an injection step of injecting a fluid into the liquid ejecting unit 1 through the opening of one of the plurality of nozzles 21, and a pressure of the fluid injected in the injection step. A discharge step of discharging the fluid containing the ink in the liquid ejecting unit 1 through the openings of the other nozzles 21 of the plurality of nozzles 21.

  That is, the liquid ejecting unit 1 communicates with the common liquid chamber 100 that can store the first liquid (ink) supplied via the liquid supply path 727 and the common liquid chamber 100 and is supplied from the common liquid chamber 100. It has a plurality of nozzles 21 that can eject one liquid onto the medium. Then, the fluid ejecting device 775D injects the fluid into the liquid ejecting unit 1 through the opening of one nozzle 21 of the plurality of nozzles 21, and causes the fluid including the first liquid (ink) to flow out of the plurality of nozzles 21. Fluid injection maintenance for discharging through the opening of another nozzle 21 is performed. In this respect, the fluid ejecting device 775D functions as a fluid injecting device capable of injecting at least one of the gas and the second liquid into the liquid ejecting unit 1 through the opening of the nozzle 21.

  In the injection process, as shown in FIG. 21, in order to discharge the foreign matter mixed in the common liquid chamber 100 of the liquid ejecting unit 1, a nozzle row NL is configured by using the fluid ejecting nozzle 778 of the fluid ejecting apparatus 775D. Fluid is injected through the openings of some of the nozzles 21. For example, the fluid ejecting device 775D disposes the fluid ejecting nozzle 778 at the first position P1, closes the on-off valve 833, and directs the second liquid having a diameter smaller than the opening diameter of the nozzle 21 toward the opening of the nozzle 21. The fluid containing small droplets DS is ejected in the first ejection direction S1 at a high speed and a high pressure for a longer time than in the first mode.

  That is, the fluid ejection device 775D that functions as a fluid injection device has an ejection port 778j that can eject the second liquid, and ejects fluid from the ejection port 778j when the ejection port 778j is away from the liquid ejection unit 1. By doing so, fluid is injected into the opening of at least one of the plurality of nozzles 21.

  The fluid injected from the nozzles 21 flows in the common liquid chamber 100 communicating with the plurality of nozzles 21 and pushes out the ink in the common liquid chamber 100 from the other nozzles 21 together with foreign substances (discharge process). Examples of the foreign matter mixed in the common liquid chamber 100 include bubbles, broken pieces of the film (solidified ink), etc., which are destroyed by the nozzle cleaning in the first mode and enter the inner side of the nozzle 21. Is mentioned.

  In the sixth mode, except that the injection time is longer than that in the first mode, the other main injection conditions are the same as those in the first mode. Therefore, the injection time of the fluid injection for nozzle cleaning in the first mode By continuing the operation, fluid ejection in the first mode and the sixth mode can be executed continuously. In this case, the fluid injecting device (fluid ejecting device 775D) ejects the fluid containing the small droplet DS of the second liquid whose diameter is smaller than the opening diameter of the nozzle 21, thereby causing one of the plurality of nozzles 21 to be ejected. The fluid is injected into the liquid ejecting unit 1 through the opening of the nozzle 21.

  During the injection process, there is a differential pressure valve 731 (one-way valve) that opens when the pressure in the liquid chamber becomes a predetermined pressure (for example, 1 kPa) lower than the pressure in the space outside the liquid chamber, upstream of the common liquid chamber 100. Since the fluid injected from the nozzle 21 does not flow backward upstream, the foreign matter in the common liquid chamber 100 can be efficiently discharged from the other nozzles 21 together with the first liquid in the discharging step. That is, in the case where the liquid supply path 727 includes the differential pressure valve 731 that functions as a supply regulating unit capable of regulating the flow of the liquid, the fluid ejection device 775D is in a state where the differential pressure valve 731 regulates the flow of the liquid upstream. It is preferable to perform fluid injection maintenance. For example, when an opening / closing valve that can be arbitrarily opened and closed is provided instead of the differential pressure valve 731, it is preferable to perform fluid injection maintenance with the opening / closing valve closed.

  Further, in the liquid supply path 727, the filter 216 is provided between the common liquid chamber 100 and the differential pressure valve 731. Therefore, even if fluid is injected into the nozzle 21, foreign matter (film fragments, etc.) is generated by the flow. 2 Inflow to the upstream flow path 502 (see FIG. 8) is suppressed.

  In the fluid injection maintenance, when the fluid ejection device 775D injects a fluid into one nozzle 21, the actuator 130 corresponding to the nozzle 21 different from the nozzle 21 that injects the fluid may be driven. In the nozzle 21 to which no fluid is injected, even if the pressure in the common liquid chamber 100 fluctuates somewhat, the ink does not leak from the nozzle 21 if the pressure fluctuation is in the meniscus withstand pressure range. Even in such a configuration, when the actuator 130 is driven to pressurize the pressure generating chamber 12 that communicates with the nozzle 21, the ink is pushed out from the nozzle 21, so that the meniscus is destroyed and the liquid flows out from the nozzle 21. be able to.

  Here, foreign matter such as filtered solid matter may accumulate and adhere to the upstream surface of the filter 216. In this case, the liquid injected from the downstream side in the fluid injection maintenance flows back from the second liquid reservoir 503a to the first liquid reservoir 502a, so that the foreign matter attached to the upstream surface of the filter 216 is separated from the filter 216. Is expected to be.

  This makes it possible to remove deposits on the filter 216 that could not be removed by the downstream flow, such as suction cleaning, by suction cleaning performed following the fluid injection maintenance operation. In addition, when a part of the wall surface forming the liquid chamber of the differential pressure valve 731 has flexibility, even if the flow of the liquid to the upstream side is restricted by the differential pressure valve 731, it fluctuates due to the deflection displacement of the wall surface. Since the amount of liquid to be flowed from the second liquid reservoir 503a to the first liquid reservoir 502a, there is a high possibility that the deposits will be separated from the filter 216.

  In the sixth mode, in order to generate a flow in one direction indicated by an arrow in FIG. 21 in the common liquid chamber 100, the nozzle on one end side in the longitudinal direction of the common liquid chamber 100 (left end side in FIG. 21). The fluid is preferably injected from the nozzle 21 and the liquid is discharged from the nozzle 21 on the other end side (the right end side in FIG. 21).

  In the sixth mode, it is sufficient that foreign matter can be discharged into the liquid ejecting unit 1, and therefore any fluid of gas, the second liquid, or a mixed fluid of the gas and the second liquid may be ejected. When any of the fluids is ejected, a fluid different from the ink (first liquid) is mixed into the liquid ejecting unit 1, and therefore, after performing the sixth mode maintenance, the suction cap 770 is used. In addition, suction cleaning using the suction pump 773 is performed, and the mixed fluid may be discharged from the liquid ejecting unit 1 by filling the nozzle 21 with the first liquid. That is, after the fluid ejection device 775D performs fluid injection maintenance in a state where the supply regulating unit (the differential pressure valve 731) regulates the flow of the liquid, the upstream side of the liquid supply path 727 in a state where the regulation of the differential pressure valve 731 is released. Ink is supplied from the nozzle to fill the first liquid up to the opening of the nozzle 21.

  The maintenance operation of the liquid ejecting unit 1 including the second to sixth modes as described above may be performed by selecting an appropriate mode every time printing is performed for a predetermined time or each time a predetermined amount of medium ST is transported. Good. Alternatively, the state of the opening surface (liquid ejecting surface 20a) is detected by a sensor or the like, and the mode is selected according to the detection state, for example, when the foreign material adheres to the liquid ejecting surface 20a, the second mode is selected. You may select and perform maintenance.

According to the above embodiment, the following effects can be obtained.
(1) In the first mode, the fluid ejecting device 775D performs the first fluid ejection on the opening region, thereby introducing the second liquid small droplet DS smaller than the opening of the nozzle 21 into the nozzle 21. Nozzle cleaning, which is maintenance for eliminating clogging of the nozzle 21, can be performed. On the other hand, in the second fluid ejection in the second mode performed by the fluid ejecting device 775D on the liquid ejecting unit 1, the second liquid droplet DL having the smallest droplet larger than the small droplet DS is ejected. The droplet DL is unlikely to enter the nozzle 21. Therefore, in the second mode, the meniscus formed in the nozzle 21 is prevented from being destroyed by the droplet DL of the second liquid entering the nozzle 21 that is not clogged. Therefore, the maintenance of the liquid ejecting unit 1 having the nozzles 21 that can eject liquid can be performed efficiently.

  (2) In the second mode, the fluid ejecting device 775D performs the second fluid ejecting on the opening region, thereby preventing the second liquid droplet DL from destroying the meniscus in the nozzle 21 while opening the opening. The area can be cleaned. Further, the fluid ejecting device 775D performs the second fluid ejection on the opening region, so that the second liquid adheres to the opening region of the liquid ejecting unit 1. Therefore, the wiping member 750B subsequently wipes the opening region, whereby maintenance (wiping) of the opening region is performed in a state where the wiping member 750B is wetted by the second liquid attached to the liquid ejecting unit 1. Thereby, since frictional resistance becomes smaller than the case where the wiping member 750B wipes the opening area in the dry state, the load applied to the opening area by the wiping operation can be reduced. In addition, since the fixed substance that is fixed to the opening area is moistened with the second liquid, the fixed substance is dissolved in the second liquid, so that the foreign matters fixed to the opening area can be efficiently removed by wiping with the wiping member 750B. it can.

  (3) In the second mode, the fluid ejecting device 775D performs the second fluid ejecting on the non-opening region, thereby suppressing the droplet DL of the second liquid from destroying the meniscus in the nozzle 21, The non-opening region can be cleaned. In addition, the wiping member 750B comes into contact with the non-opening region after the second fluid ejection, so that the wiping member 750B can be wetted with the second liquid. Therefore, the wiping member 750B subsequently wipes the opening area, so that the load applied to the opening area can be reduced as compared with the case of wiping the opening area in a dry state, and the foreign matters attached to the opening area can be removed. it can.

  (4) By making the main component of the second liquid pure water, even when the second liquid enters the nozzle 21, the deterioration due to mixing with the second liquid of the first liquid in the nozzle 21 is suppressed. can do. Moreover, when the preservative is contained in the pure water as the main component, the decay of the second liquid held in the fluid ejecting devices 775 and 775D can be suppressed.

  (5) The fluid ejecting device 775B ejects the fluid containing the third liquid containing the liquid repellent component, thereby attaching the third liquid to the liquid ejecting unit 1 and improving the liquid repellency of the liquid ejecting unit 1. be able to. Then, by improving the liquid repellency of the liquid ejecting unit 1, the liquid ejecting unit 1 ejects the first liquid from the nozzle 21 toward the medium ST, so that a minute mist of the first liquid is unintentionally generated. Even when the mist adheres to the liquid ejecting unit 1, the first liquid can be prevented from sticking to the liquid ejecting unit 1.

  (6) Since the distance from the ejection port 778j when the fluid ejection device 775D performs the second fluid ejection in the second mode to the liquid ejection unit 1 is longer than when the first fluid ejection is performed in the first mode, The flying speed of the droplet of the second liquid that reaches the liquid ejecting unit 1 by the two-fluid ejection is relatively slow. Thereby, it becomes difficult for the second liquid to enter the nozzle 21, and even if it enters, the impact when colliding with the meniscus is reduced, so that the meniscus can be prevented from being destroyed. In addition, if the flying speed of the liquid droplet is high, there is a possibility that the liquid ejecting section 1 will be vigorously collided and scattered around. However, by making the flying speed of the liquid droplet slow, the liquid ejecting section 1 is contacted. The second liquid can be efficiently attached to the liquid ejecting unit 1 while suppressing scattering of the time.

  (7) Since the intersection angle of the second ejection direction S2 with respect to the opening surface (liquid ejection surface 20a) where the nozzle 21 opens is smaller than the intersection angle of the first ejection direction S1 with respect to the opening surface, the second fluid ejection is performed. The second liquid droplet DL is unlikely to enter the nozzle 21. Therefore, in the second mode, the meniscus destruction of the nozzle 21 due to the second fluid ejection can be suppressed.

  (8) Since the angle of the gas injection direction (third injection direction S3) with respect to the opening surface (liquid injection surface 20a) where the nozzle 21 opens is 0 ° ≦ θ <90 °, the gas injected from the injection port 778j is It is suppressed that the meniscus is disturbed by entering the nozzle 21. Further, the fluid ejecting device 775D injects the gas onto the liquid ejecting unit 1 in a state where the angle with respect to the opening surface is reduced, thereby causing the gas to flow along the opening surface and blowing off the deposits attached to the liquid ejecting unit 1. Can be removed efficiently.

  (9) The kinetic energy of the droplet ejected from the ejection port 778j or the nozzle 21 is obtained by the product of the mass of the droplet and the square of the flying speed of the droplet at a predetermined position. If the kinetic energy of the first liquid droplet ejected from the nozzle 21 by the liquid ejecting unit 1 is large, even if the nozzle 21 is slightly clogged, the clogging is caused by the energy of the droplet. Can be resolved. On the other hand, when the nozzle 21 is severely clogged, the clogging cannot be eliminated by the energy for ejecting the first liquid droplet from the nozzle 21. In that respect, in the first mode, the kinetic energy at the opening position of the nozzle 21 of the small droplet DS ejected from the ejection port 778j toward the nozzle 21 by the fluid ejection device 775D causes the droplet of the first liquid to be ejected from the nozzle 21. Greater than the energy to be injected. Therefore, when the small droplet DS of the second liquid ejected by the fluid ejecting device 775D enters the nozzle 21, the clogging of the nozzle 21 that cannot be eliminated by the ejecting operation of ejecting the first liquid droplet from the opening of the nozzle 21. Can be solved by kinetic energy.

  (10) When the fluid ejecting device 775D performs the first fluid ejecting on the opening region of the liquid ejecting unit 1, the actuator 130 is driven in the liquid ejecting unit 1 and the inside of the pressure generating chamber 12 communicating with the nozzle 21 is passed. By pressurizing, the pressure in the nozzle 21 increases. Then, the small droplet DS of the second liquid ejected by the fluid ejecting device 775D is less likely to enter the inner side of the nozzle 21. Therefore, when the film is stretched at the opening of the nozzle 21 in the liquid ejecting section 1, the second liquid droplets DS ejected by the fluid ejecting device 775D collide with the film stretched at the opening of the nozzle 21 to form the film. While destroying, it is suppressed that foreign matters, such as the destroyed film, enter the nozzle 21. Therefore, even when droplets are ejected from the outside of the nozzle 21 to eliminate clogging, mixing of the droplets or foreign matter into the nozzle 21 can be suppressed.

  (11) Prior to the cap 771 capping, the liquid adhering device (fluid ejecting device 775D) attaches the second liquid to the liquid ejecting unit 1, so that when the cap 771 capping and forms a closed space The second liquid can be present near the nozzle 21. Therefore, the nozzle 21 can be efficiently moisturized by the second liquid that evaporates in the vicinity of the nozzle 21.

  (12) Since the second liquid can be adhered to the liquid ejecting unit 1 by ejecting the second liquid from the ejection port 778j by the liquid adhering device (fluid ejecting device 775D), A fluid ejection device 775D can be disposed.

  (13) By mixing the gas with the second liquid ejected by the liquid adhesion device (fluid ejecting device 775D), the second liquid can be made to fly in smaller droplets. And by ejecting such fine droplets, the second liquid can be uniformly attached to a predetermined region of the liquid ejecting unit 1.

  (14) If the second liquid is attached to the opening region where the nozzle 21 is opened, the second liquid may enter the nozzle 21 and mix with the first liquid. In this regard, if the second liquid is attached to the non-opening area that does not include the opening area in the liquid ejecting unit 1, the second liquid can be prevented from entering the nozzle 21.

  (15) The liquid adhering device (fluid ejecting device 775D) ejects the small droplet DS of the second liquid into the opening region, thereby introducing the small droplet DS into the nozzle 21 and clogging the nozzle 21. Nozzle cleaning, which is maintenance for eliminating the problem, can be performed. At this time, since the second liquid that has not entered the nozzle 21 adheres to the opening region, the second liquid is consumed for moisture retention by performing capping so that the attached second liquid is included in the closed space. In addition, the nozzle 21 can be moisturized without separately performing the operation for causing the second liquid to adhere to the liquid ejecting unit 1, which is efficient.

  (16) By performing wiping after the execution of the first fluid ejection by the liquid adhesion device (fluid ejection device 775D), the foreign matter adhered to the opening region is removed together with the second liquid adhered to the opening region by the first fluid ejection. Since it can be removed, the liquid ejecting unit 1 can be efficiently maintained. In addition, the liquid ejecting unit 1 can be cleaned by executing the second fluid ejecting by the fluid ejecting apparatus 775D, and the second liquid is attached to the liquid ejecting unit 1 by performing the second fluid ejecting. By performing capping, it is not necessary to perform an operation for attaching the second liquid to the liquid ejecting unit 1 separately. Further, in the first fluid injection, since the clogging is eliminated by introducing the small droplet DS into the nozzle 21, the meniscus in the nozzle 21 may be disturbed after the first fluid injection is executed. High nature. On the other hand, in the second fluid ejection, since the droplet having the smallest droplet larger than the small droplet DS is ejected, the possibility that the second liquid enters the nozzle 21 and breaks the meniscus is small. Therefore, if capping is performed after the second fluid ejection is performed, it is possible to suppress the nozzle 21 from being left in a state where the meniscus is disturbed, as compared to the case where capping is performed after the first fluid ejection is performed.

  (17) The liquid adhering device (fluid ejecting device 775D) adheres the second liquid to the wiping area to be wiped by the wiping member 750B, so that the foreign matter adhering to the wiping area is dissolved in the second liquid, and the foreign matter is efficiently removed. Can be removed. Moreover, since the frictional resistance when the wiping member 750B comes into contact with the wiped area is reduced by making the second liquid foam, the liquid ejecting unit is removed when the liquid ejecting unit 1 is wiped by the wiping member 750B. 1 can be reduced.

  (18) In the fluid ejection device 775D, by mixing the gas with the second liquid, the fluid ejected from the ejection port 778j can include the gas. Two liquids can be efficiently foamed.

  (19) In the first mode nozzle cleaning, small droplets DS can be introduced into the nozzle 21 to eliminate the clogging. In the nozzle cleaning, the second liquid is prevented from being foamed by shortening the ejection duration time for ejecting the fluid, so that the small droplet DS does not easily enter the nozzle 21 due to the foam. On the other hand, in the fourth mode, the second liquid can be made into a foam shape by lengthening the ejection duration time for ejecting the fluid. Therefore, the liquid adhering device (fluid ejecting device 775D) for cleaning the nozzle is used in the first mode. It can also be used as an apparatus for making two liquids foam.

  (20) The wiping area to be wiped includes an opening area where the nozzle 21 is opened in the liquid ejecting unit 1, and the wiping member 750 </ b> B wipes the opening area so that the foreign matter adhered to the vicinity of the opening of the nozzle 21. Can be removed.

  (21) When the second liquid enters the nozzle 21, the meniscus of the nozzle 21 may be disturbed, or the first liquid and the second liquid in the nozzle 21 may be mixed. In that regard, when the liquid adhering device (fluid ejecting device 775D) adheres the foam-like second liquid to the non-opening region located outside the opening region, the mixing of the second liquid into the nozzle 21 is suppressed. be able to.

  (22) When the caps 770 and 771 come into contact with the liquid ejecting unit 1, the liquid adhering to the liquid ejecting unit 1 gathers at the contact portions with the caps 770 and 771, and the caps 770 and 771 eject the liquid. After leaving the part 1, contact marks of the caps 770 and 771 may remain on the liquid ejecting part 1. In that respect, the liquid adhering device (fluid ejecting device 775D) adheres the foam-like second liquid to the region including the contact region where the caps 770 and 771 come into contact, and the wiping member 750B wipes the region, thereby ejecting the liquid. The contact traces of the caps 770 and 771 attached to the portion 1 can be efficiently removed.

  (23) Due to the effect of the preservative containing at least one of the aromatic halogen compound, methylene dithiocyanate and halogen-containing nitrogen-sulfur compound contained in the second liquid, it is possible to suitably suppress the decay of the second liquid. .

  (24) In the fluid injection maintenance, the fluid injection device (fluid ejection device 775D) injects the fluid into the liquid ejection unit 1 through the opening of the one nozzle 21 so that the plurality of nozzles 21 and the nozzles 21 communicate with each other. The foreign matter in the common liquid chamber 100 can be discharged from the opening of the other nozzle 21 together with the first liquid in the common liquid chamber 100. Therefore, foreign matter existing in the liquid ejecting unit 1 having the plurality of nozzles 21 can be discharged.

  (25) When the supply restricting unit (the differential pressure valve 731) restricts the flow of the liquid when the fluid injecting maintenance is performed, the fluid injected from the nozzle 21 by the fluid injecting device (fluid ejecting device 775D) is upstream. Since it does not flow, the injected fluid can be efficiently discharged from the other nozzles 21.

  (26) In the process of supplying the first liquid from the upstream side of the liquid supply path 727 and filling the first liquid up to the opening of the nozzle 21 after the fluid injection maintenance, the fluid ejecting apparatus is replaced with the first liquid to be filled. Since the second liquid injected from the nozzle 21 by the 775D is discharged, foreign matter in the common liquid chamber 100 can be discharged together with the second liquid. In addition, by filling the first liquid up to the opening of the nozzle 21 in this way, it is possible to prepare for the next liquid ejecting operation.

  (27) In the fluid injection maintenance, foreign matter is introduced into the differential pressure valve 731 along the flow of the fluid injected from the nozzle 21 by the filter 216 positioned between the supply regulating unit (the differential pressure valve 731) and the common liquid chamber 100. It can be suppressed from flowing in the direction. In addition, when the fluid injected from the nozzle 21 applies pressure from the downstream side of the filter 216, solid matter or the like accumulated on the upstream side of the filter 216 can be peeled off from the filter 216.

  (28) When performing the fluid injection maintenance, the fluid injection device (fluid ejection device 775D) drives the actuator 130 corresponding to another nozzle 21 different from the nozzle 21 into which the fluid has been injected, so that the other nozzles 21 The discharge of fluid can be promoted.

  (29) Since the ejection port 778j from which the fluid injection device (fluid ejection device 775D) ejects the second liquid is disposed at a position away from the liquid ejection unit 1, the ejection port of the first liquid ejected by the liquid ejection unit 1 Attachment to 778j can be suppressed.

  (30) The fluid injecting device (fluid ejecting device 775D) ejects the fluid containing the small droplet DS of the second liquid that is smaller than the opening of the nozzle 21, so that the energy of the small droplet DS collides with the energy of the nozzle 21 Clogging can be eliminated. When foreign matter that has caused clogging of the nozzle 21 enters the common liquid chamber 100 inside the nozzle 21, the foreign matter is discharged by fluid injection maintenance performed by the fluid injection device (fluid ejection device 775D). can do. Accordingly, the configuration of the liquid ejecting apparatus 7 is more than the case where a device for eliminating the clogging of the nozzle 21 is provided separately because the apparatus for eliminating the clogging of the nozzle 21 is also used by the (fluid ejecting apparatus 775D). It can be simplified.

In addition, you may change each said embodiment like the example of a change shown below. In addition, the above embodiments and the following modifications can be used in any combination.
As in the first modification shown in FIG. 22, the liquid ejecting section 1 (1C) having two liquid ejecting heads 3 (3A, 3B) to which ink is supplied from one differential pressure valve 731 through the supply flow path 732 In some cases, maintenance of the liquid ejecting heads 3A and 3B may be performed by the fluid ejecting apparatuses 775, 775B, and 775D. Further, in the liquid ejecting unit 1C, it is possible to perform fluid injection maintenance for injecting fluid from all the nozzles 21 of one liquid ejecting head 3A and discharging the liquid from all the nozzles 21 of the other liquid ejecting head 3B.

  In this case, the liquid may be injected using a liquid injection device 835 as shown in FIG. 22 for fluid injection maintenance. That is, the liquid injection device 835 includes a storage unit 836 that stores the liquid for injection, a cap 837 that can form a closed space in which the nozzle 21 of the liquid ejecting head 3 opens, and a connection that connects the storage unit 836 and the cap 837. A flow path 838 and a supply pump 839 that pressurizes and supplies the liquid in the reservoir 836 toward the cap 837. Then, the cap 837 is brought into contact with the liquid jet head 3A, for example, to form a closed space, and the supply pump 839 is driven to pressurize and supply the liquid for injection into the closed space. Then, as indicated by an arrow in FIG. 22, the pressurized liquid in the closed space enters from the opening of the nozzle 21, and the common liquid chamber 100, the supply flow path 732, and the other liquid jet head 3B of the liquid jet head 3A. And the liquid is discharged from the nozzle 21 of the liquid jet head 3B together with the foreign matter.

  As in the second modification shown in FIG. 23, the second liquid supplied from the liquid flow path 788a and the air supplied from the gas flow path 783a are mixed instead of the external mixing type fluid ejection nozzle 778. Alternatively, a so-called internal mixing type fluid ejection nozzle 778B having a mixing portion KA that generates a mixed fluid therein may be used. In this case, the mixed fluid generated by the mixing unit KA is ejected from the ejection port 778j provided at the tip (upper end) of the fluid ejection nozzle 778B.

  -About the fluid injection of each mode in the said 2nd Embodiment, the injection direction, the injection speed, the droplet diameter, and the injection pressure can be changed arbitrarily. For example, the fluid ejection device 775 similar to that of the first embodiment may be used to perform the fluid ejection in each mode in the first ejection direction S1.

  Before ejecting the mixed fluid from the fluid ejecting nozzle 778 to the liquid ejecting units 1A and 1B including the nozzle 21, the second liquid is ejected to the liquid ejecting units 1A and 1B including the nozzle 21. Also good. In this case, the liquid supply pump 793 may be used to eject the second liquid from the liquid ejecting nozzle 780, but a pump for ejecting the second liquid from the liquid ejecting nozzle 780 is separately provided in the middle of the liquid supply pipe 788. It is preferable to provide it. If it does in this way, since it will inject the 2nd liquid first with respect to liquid injection part 1A, 1B containing the nozzle 21, mixes air in the said 2nd liquid after that, and will come to inject a fluid mixture. Moreover, it can suppress that only air is injected with respect to liquid-injection part 1A, 1B containing the nozzle 21. FIG. Therefore, it is possible to suppress the air injected to the liquid ejecting units 1A and 1B including the nozzle 21 from entering the interior of the liquid ejecting units 1A and 1B from the opening of the nozzle 21. Further, in this case, even when the injection of the mixed fluid to the liquid injection units 1A and 1B including the nozzle 21 is stopped, by stopping the injection of air first and stopping the injection of the second liquid later, It can suppress that only air is injected with respect to liquid injection part 1A, 1B containing the nozzle 21. FIG.

  A fluid ejection failure in the fluid ejection devices 775B and 775D may be detected using a temperature sensor 711 (see FIG. 2) provided on the carriage 723. That is, a liquid or a fluid containing liquid is ejected from the fluid ejection nozzle 778 of the fluid ejection device 775,775D or the fluid ejection nozzle 778B of the fluid ejection device 775B toward the temperature sensor 711, and the detection result of the temperature sensor 711 at that time Based on the above, the ejection failure of the fluid in the fluid ejection devices 775B and 775D is detected.

  Specifically, if the liquid is properly ejected from the fluid ejecting nozzles 778 and 778B, the temperature sensor 711 is cooled by the liquid sensor coming into contact with the temperature sensor 711, so that the temperature sensor 711 detects a decrease in temperature. By doing so, it can be detected that the liquid is appropriately ejected from the fluid ejection nozzles 778 and 778B. On the other hand, if the temperature of the temperature sensor 711 does not decrease even though the fluid ejecting devices 775 and 775D perform the ejecting operation, the fluid ejection nozzles 778 and 778B may be clogged or run out of liquid, causing liquid ejection failure. It can be determined that it has occurred.

  A clogged nozzle 21 provided with a pressurizing pump for supplying ink in an ink tank (not shown) to the reservoir 730 during ejection of the mixed fluid from the fluid ejection nozzle 778 to the clogged nozzle 21; The pressurization of the ink in the pressure generation chamber 12 that communicates may be performed by the pressurization pump with the differential pressure valve 731 opened.

  Before ejecting the mixed fluid from the fluid ejecting nozzle 778 to the liquid ejecting units 1A and 1B including the nozzle 21, the second liquid is ejected to a region not including the nozzle 21 of the liquid ejecting units 1A and 1B. You may do it. Further, before the mixed fluid is ejected from the fluid ejecting nozzle 778 to the liquid ejecting units 1A and 1B including the nozzle 21, the second liquid is ejected at a position where the fluid ejecting nozzle 778 does not face the liquid ejecting units 1A and 1B. You may make it do. Even if it does in this way, it can suppress that only air is injected with respect to liquid injection part 1A, 1B containing the nozzle 21. FIG.

  -The 2nd liquid which is a 2nd liquid may comprise only pure water (pure water which does not contain antiseptic | preservative). In this way, when the second liquid is mixed with the ink in the nozzle 21, it is possible to suppress the second liquid from adversely affecting the ink.

  When the mixed fluid is ejected to the clogged nozzle 21, the actuator 130 corresponding to the clogged nozzle 21 may be driven in the same manner as during ink ejection or flushing during printing. Even in this case, the mixed fluid can be prevented from entering the clogged nozzle 21.

  When the mixed fluid is ejected to the clogged nozzle 21, the actuator 130 corresponding to the nozzle 21 other than the clogged nozzle 21 is driven to correspond to the nozzle 21 other than the clogged nozzle 21 You may make it pressurize each pressure generation chamber 12 to perform. In this way, the mixed fluid can be prevented from entering the nozzles 21 other than the clogged nozzle 21.

The fluid ejecting device 775 may be disposed in the non-printing area RA.
A wiper for wiping the liquid ejecting surface 20a of the liquid ejecting units 1A and 1B may be separately provided between the fluid ejecting device 775 and the printing area PA in the non-printing area LA. In this way, after the fluid ejection device 775 ejects the mixed fluid to the liquid ejecting units 1A and 1B, the mixed fluid (second liquid is transferred before moving the printing unit 720 to the home position HP side across the printing area PA. ) Can be wiped with the wiper. Therefore, it is possible to prevent the mixed fluid (second liquid) attached to the liquid ejection surface 20a from dripping during the movement of the printing unit 720 in the printing area PA.

  In place of the air pump 782, an air compressor of equipment such as a factory may be used. In this case, a three-way electromagnetic valve capable of opening the gas flow path 783a to the atmosphere is provided at a position between the pressure adjustment valve 784 and the air filter 785 in the gas supply pipe 783 so that the gas flow can be performed when the fluid ejection device 775 is not used. The path 783a may be opened to the atmosphere.

  When the control unit 810 detects the nozzle 21 that does not clear the clogging even if the suction cleaning is performed a predetermined number of times based on the clogging detection history, the nozzle 21 that temporarily does not clear the clogging is not used. Alternatively, so-called complementary printing may be performed in which printing is performed by ejecting ink from another normal nozzle 21 instead. In this case, the clogging may be eliminated by washing the nozzles 21 whose clogging is not eliminated even if the suction cleaning is performed a predetermined number of times after complementary printing with the fluid ejecting devices 775 and 775D.

  The nozzle row NL (nozzle 21) that ejects ink of a color (kind) that is used infrequently is used without regular maintenance (suction cleaning, flushing, wiping, etc.) The clogging may be eliminated by washing with the fluid ejecting devices 775 and 775D. In this way, the amount of ink used for suction cleaning and flushing of ink (type) of color that is very infrequent is reduced, so that the ink can be saved.

During the ejection of the mixed fluid from the fluid ejection nozzle 778 to the clogged nozzle 21, it is not always necessary to pressurize the pressure generation chamber 12 communicating with the clogged nozzle 21.
The product of the mass of the droplet of the second liquid smaller than the opening of the nozzle 21 and the square of the flying speed of the droplet at the opening position of the nozzle 21 is not necessarily the mass of the ink droplet ejected from the opening of the nozzle 21 It is not necessary to make it larger than the product of the flying speed of the ink droplet and the square of the flying speed.

  The liquid ejected by the liquid ejecting unit is not limited to ink, and may be, for example, a liquid material in which functional material particles are dispersed or mixed in the liquid. For example, recording is performed by ejecting a liquid material in which a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. It may be configured.

The medium is not limited to paper, and may be a plastic film, a thin plate, or the like, or may be a fabric used in a printing apparatus.
Next, ink (colored ink) as the first liquid will be described in detail below.

  The ink used for the liquid ejecting apparatus 7 contains a resin in terms of composition and substantially does not contain glycerin having a boiling point of 290 ° C. under 1 atm. If the ink substantially contains glycerin, the drying property of the ink is greatly reduced. As a result, in various media, in particular, a non-ink-absorbing or low-absorbing medium, not only the density unevenness of the image is noticeable but also the ink fixing property cannot be obtained. Furthermore, it is preferable that the ink substantially does not contain alkyl polyols (excluding the above glycerin) having a boiling point of 280 ° C. or higher at 1 atm.

  Here, “substantially free” in the present specification means not to contain more than the amount that fully exhibits the significance of addition. Speaking quantitatively, it is preferable not to contain 1.0 mass% or more of glycerin with respect to the total mass (100 mass%) of an ink, and it is more preferable not to contain 0.5 mass% or more. More preferably, it is not contained in an amount of not less than 1% by mass, more preferably not in excess of 0.05% by mass, and particularly preferably not in excess of 0.01% by mass. And it is most preferable not to contain glycerol 0.001 mass% or more.

Next, additives (components) that are or can be included in the ink will be described.
[1. Color material]
The ink may include a color material. The color material is selected from pigments and dyes.

[1-1. Pigment]
By using a pigment as the color material, the light resistance of the ink can be improved. As the pigment, both inorganic pigments and organic pigments can be used. The inorganic pigment is not particularly limited, and examples thereof include carbon black, iron oxide, titanium oxide, and silica oxide.

  Examples of organic pigments include, but are not limited to, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments Examples include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. . Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4 and 60 are listed. Among them, C.I. I. Any one of CI Pigment Blue 15: 3 and 15: 4 is preferable.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50. Among them, C.I. I. Pigment red 122, C.I. I. Pigment red 202, and C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferred.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213. Among them, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 74, 155, and 213 are preferred.

In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used.
The average particle diameter of the pigment is preferably 250 nm or less because clogging at the nozzle 21 can be suppressed and the ejection stability is further improved. In addition, the average particle diameter in this specification is based on a volume. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring device include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

[1-2. dye]
A dye can be used as the coloring material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. The content of the color material is preferably 0.4 to 12% by mass, and more preferably 2% by mass or more and 5% by mass or less with respect to the total mass (100% by mass) of the ink.

[2. resin]
The ink contains a resin. When the ink contains a resin, a resin film is formed on the medium. As a result, the ink is sufficiently fixed on the medium, and the effect of mainly improving the abrasion resistance of the image is exhibited. For this reason, the resin emulsion is preferably a thermoplastic resin. The heat deformation temperature of the resin is preferably 40 ° C. or more, and is preferably 60 ° C. or more, because the advantageous effect that the nozzle 21 is not easily clogged and the medium has abrasion resistance is obtained. More preferred.

  Here, the “thermal deformation temperature” in the present specification is a temperature value represented by a glass transition temperature (Tg) or a minimum film forming temperature (MFT). That is, “the thermal deformation temperature is 40 ° C. or higher” means that either Tg or MFT may be 40 ° C. or higher. In addition, since MFT can grasp | ascertain the superiority or inferiority of the redispersibility of resin rather than Tg, it is preferable that the said heat deformation temperature is a temperature value represented by MFT. If the ink is excellent in resin redispersibility, the ink does not adhere and the nozzle 21 is less likely to be clogged.

  Although it does not specifically limit as a specific example of the said thermoplastic resin, Poly (meth) acrylic acid ester or its copolymer, polyacrylonitrile or its copolymer, polycyanoacrylate, polyacrylamide, poly (meth) acrylic acid, etc. (Meth) acrylic polymers, polyethylene, polypropylene, polybutene, polyisobutylene, and polystyrene, and copolymers thereof, and polyolefin polymers such as petroleum resins, coumarone-indene resins, and terpene resins, polyvinyl acetate Or copolymers thereof, vinyl acetate-based or vinyl alcohol-based polymers such as polyvinyl alcohol, polyvinyl acetal, and polyvinyl ether, polyvinyl chloride or copolymers thereof, polyvinylidene chloride, fluororesin, and fluorine-containing halogenated compounds such as fluororubber. -Based polymers, polyvinylcarbazole, polyvinylpyrrolidone or copolymers thereof, nitrogen-containing vinyl polymers such as polyvinylpyridine and polyvinylimidazole, polybutadienes or copolymers thereof, polychloroprene, and diene systems such as polyisoprene (butyl rubber) Examples include polymers, and other ring-opening polymerization resins, condensation polymerization resins, and natural polymer resins.

  The content of the resin is preferably 1 to 30% by mass, and more preferably 1 to 5% by mass with respect to the total mass (100% by mass) of the ink. When content is in the said range, the glossiness and abrasion resistance of the top coat image formed can be made further excellent. Examples of the resin that may be contained in the ink include a resin dispersant, a resin emulsion, and a wax.

[2-1. Resin emulsion]
The ink may contain a resin emulsion. When the medium is heated, the resin emulsion preferably forms a resin film together with the wax (emulsion), thereby exhibiting an effect of sufficiently fixing the ink on the medium and improving the abrasion resistance of the image. When the medium is printed with the ink containing the resin emulsion due to the above-described effect, the ink has excellent abrasion resistance particularly on a non-ink-absorbing or low-absorbing medium.

  The resin emulsion that functions as a binder is contained in the ink in an emulsion state. By including a resin functioning as a binder in the ink in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink can be improved.

  Examples of the resin emulsion include, but are not limited to, (meth) acrylic acid, (meth) acrylic acid ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone. , Vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride homopolymers or copolymers, fluororesins, and natural resins. Among them, either a methacrylic resin or a styrene-methacrylic acid copolymer resin is preferable, either an acrylic resin or a styrene-acrylic acid copolymer resin is more preferable, and a styrene-acrylic acid copolymer resin is more preferable. Even more preferred. In addition, said copolymer may be any form among a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  The average particle diameter of the resin emulsion is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink. Among the resins, the content of the resin emulsion is preferably in the range of 0.5 to 7% by mass with respect to the total mass (100% by mass) of the ink. When the content is within the above range, the solid content concentration can be lowered, so that the discharge stability can be further improved.

[2-2. wax]
The ink may include wax. When the ink contains a wax, the fixability of the ink on a non-ink-absorbing and low-absorbing medium is further improved. Among them, an emulsion type is more preferable. Examples of the wax include, but are not limited to, polyethylene wax, paraffin wax, and polyolefin wax. Among them, polyethylene wax described later is preferable. In the present specification, the “wax” means a product in which solid wax particles are dispersed in water mainly using a surfactant described later.

  When the ink contains polyethylene wax, the ink can have excellent abrasion resistance. The average particle diameter of the polyethylene wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

  The polyethylene wax content (in terms of solid content) is preferably in the range of 0.1 to 3% by mass, independently of the total mass (100% by mass) of the ink, and 0.3 to 3%. The range is more preferably in the range of mass%, and further preferably in the range of 0.3 to 1.5 mass%. When the content is within the above range, the ink can be solidified and fixed satisfactorily even on a non-ink-absorbing or low-absorbing medium, and the storage stability and ejection stability of the ink are further improved. Can be.

[3. Surfactant]
The ink may contain a surfactant. Examples of the surfactant include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of spreading the ink uniformly on the medium. For this reason, when printing is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding is obtained. Examples of such nonionic surfactants include, but are not limited to, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivatives, and fluorine-based interfaces. Examples of the surfactant include silicon surfactants.

  The content of the surfactant is that the storage stability and ejection stability of the ink are further improved. A range is preferable.

[4. Organic solvent]
The ink may contain a known volatile water-soluble organic solvent. However, as described above, the ink contains substantially no glycerin (boiling point at 290 ° C. under 1 atm), which is a kind of organic solvent, and alkyl polyols having a boiling point of 280 ° C. or more under 1 atm. It is preferable that it does not contain substantially (except the said glycerol).

[5. Aprotic polar solvent]
The ink may include an aprotic polar solvent. By containing the aprotic polar solvent in the ink, the above-described resin particles contained in the ink are dissolved, so that clogging of the nozzles 21 can be effectively suppressed during printing. Further, since it has a property of dissolving a medium such as vinyl chloride, image adhesion is improved.

  The aprotic polar solvent is not particularly limited, but one or more selected from pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, amide ethers It is preferable to contain. Representative examples of pyrrolidones include 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. Representative examples of lactones include γ-butyrolactone, γ-valerolactone, and ε-caprolactone. Typical examples of sulfoxides include dimethyl sulfoxide and tetramethylene sulfoxide.

  Typical examples of imidazolidinones include 1,3-dimethyl-2-imidazolidinone, typical examples of sulfolanes include sulfolane and dimethylsulfolane, and typical examples of urea derivatives include dimethylurea, There is 1,1,3,3-tetramethylurea. Representative examples of dialkylamides include dimethylformamide and dimethylacetamide, and representative examples of cyclic ethers include 1,4-dioxane and tetrahydrofuran.

  Among these, pyrrolidones, lactones, sulfoxides, and amide ethers are particularly preferable from the viewpoint of the effects described above, and 2-pyrrolidone is most preferable. The content of the aprotic polar solvent is preferably in the range of 3 to 30% by mass and more preferably in the range of 8 to 20% by mass with respect to the total mass (100% by mass) of the ink. preferable.

[6. Other ingredients]
The ink may further contain a fungicide, a rust inhibitor, a chelating agent, and the like in addition to the above components.

Next, the component of the surfactant mixed in the second liquid will be described.
Surfactants include cationic surfactants such as alkylamine salts and quaternary ammonium salts; anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, and fatty acid salts; alkyldimethylamine oxides , Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers Among these, an anionic surfactant or a nonionic surfactant is particularly preferable.

  The content of the surfactant is preferably 0.1 to 5.0% by mass with respect to the total mass of the second liquid. Furthermore, it is preferable that content of surfactant is 0.5-1.5 mass% with respect to the total mass of a 2nd liquid from a viewpoint of bubble property and the defoaming property after a bubble. In addition, only 1 type may be sufficient as surfactant, and 2 or more types may be sufficient as it. The surfactant contained in the second liquid is preferably the same as the surfactant contained in the ink (first liquid). For example, the surfactant contained in the ink (first liquid) In the case where is a nonionic surfactant, the nonionic surfactant is not limited to the following, for example, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivatives , And fluorine-based surfactants, among which silicon-based surfactants are preferable.

  In particular, the foam height immediately after foaming using the Ross Miles method and after 5 minutes of foaming is in the above range (the foam height immediately after foaming is 50 mm or more and the foam height after 5 minutes of foaming is 5 mm or less). In order to achieve this, an adduct obtained by adding ethylene oxide (EO) to acetylenic diol with an addition mole number of 4 to 30 as the surfactant is used, and the content of the adduct is 0% with respect to the total weight of the cleaning liquid. 0.1 to 3.0% by weight is preferable. Furthermore, the foam height immediately after foaming using the Ross Miles method and after 5 minutes of foaming is the above preferred range (the foam height immediately after foaming is 100 mm or more, the foam height after 5 minutes of foaming is 5 mm or less) In order to achieve this, an adduct obtained by adding ethylene oxide (EO) to acetylene diol with an addition mole number of 10 to 20 is used, and the content of the adduct is 0.5 to 1 with respect to the total weight of the cleaning liquid. Preferably, the content is 5% by weight. However, if the content of the ethylene oxide adduct of acetylene diol is too large, the critical micelle concentration may be reached, resulting in an emulsion.

  The surfactant has a function of facilitating the wetting and spreading of the aqueous ink on the recording medium. The surfactant that can be used in the present invention is not particularly limited, and anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, and fatty acid salts; polyoxyethylene alkyl ethers, polyoxyethylene alkylallyl Nonionic surfactants such as ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers; Cationic surfactants such as alkylamine salts and quaternary ammonium salts; Silicone surfactants; A fluorine-based surfactant or the like can be used.

  The surfactant has an effect of subdividing and dispersing the aggregate due to the surface active effect between the cleaning liquid (second liquid) and the aggregate. Further, since it has a function of reducing the surface tension of the cleaning liquid, the cleaning liquid easily enters between the aggregate and the liquid ejecting surface 20a, and has an effect of easily separating the aggregate from the liquid ejecting surface 20a.

  As the surfactant, any compound having a hydrophilic part and a hydrophobic part in the same molecule can be preferably used. As specific examples, those represented by the following formulas (I) to (IV) are preferable. That is, a polyoxyethylene alkylphenyl ether surfactant of the following formula (I), an acetylene glycol surfactant of the formula (II), a polyoxyethylene alkyl ether surfactant of the following formula (III) and the formula (IV ) Polyoxyethylene polyoxypropylene alkyl ether surfactants.

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k: 5 to 20)

(M, n ≦ 20, 0 <m + n ≦ 40)

(R is a C6-C14 hydrocarbon chain which may be branched, n is 5-20)

(R is a hydrocarbon chain having 6 to 14 carbon atoms, m and n are numbers of 20 or less)
Other than the compounds of the above formulas (I) to (IV), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl Use alkyl and aryl ethers of polyhydric alcohols such as ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol However, diethylene glycol monobutyl ether is particularly preferable.

  F ... jetting direction, DS ... small droplet, S1 ... first jetting direction, S2 ... second jetting direction, ST ... medium, 1, 1A, 1B, 1C ... liquid jetting unit, 7 ... liquid jetting device, 12 ... pressure Generation chamber, 21 ... Nozzle, 100 ... Common liquid chamber, 130 ... Actuator, 216 ... Filter, 727 ... Liquid supply path, 750a, 750B ... Wiping member, 770, 771 ... Cap, 775, 775B, 775D ... Fluid ejection device, 778j ... injection port.

Claims (10)

A common liquid chamber capable of storing a first liquid supplied via a liquid supply path, and a plurality of the first liquid supplied from the common liquid chamber and in communication with the common liquid chamber and capable of ejecting the first liquid to the medium A liquid ejecting section having a nozzle;
A fluid injecting device capable of injecting at least one of a gas and a second liquid into the liquid ejecting unit through the opening of the nozzle;
With
The fluid injecting device injects the fluid into the liquid ejecting unit through an opening of one of the plurality of nozzles, and supplies a fluid containing the first liquid to an opening of another nozzle of the plurality of nozzles. A liquid ejecting apparatus characterized by performing maintenance of fluid injection to be discharged through. In the liquid supply path, provided with a supply regulating unit capable of regulating the flow of liquid,
The liquid ejecting apparatus according to claim 1, wherein the fluid injecting device performs the fluid injecting maintenance in a state where the supply restricting unit restricts the flow of the liquid. After the fluid injection device performs the fluid injection maintenance in a state where the supply restricting portion restricts the flow of the liquid, the supply restricting portion releases the restriction, and then the upstream side of the liquid supply path The liquid ejecting apparatus according to claim 2, wherein one liquid is supplied to fill the first liquid up to an opening of the nozzle. 4. The liquid ejecting apparatus according to claim 2, wherein the liquid supply path includes a filter between the supply restricting unit and the common liquid chamber. The liquid ejecting section includes a pressure generation chamber communicating with the common liquid chamber and the nozzle, and an actuator capable of pressurizing the pressure generation chamber.
The actuator corresponding to the other nozzle different from the one nozzle is driven when the fluid injection device injects the fluid into the one nozzle in the fluid injection maintenance. The liquid ejecting apparatus according to claim 1. The fluid injection device has an ejection port capable of ejecting the second liquid, and ejects the fluid from the ejection port in a state where the ejection port is separated from the liquid ejection unit, whereby the plurality of nozzles The liquid ejecting apparatus according to claim 1, wherein the fluid is injected into an opening of at least one of the nozzles. The fluid injection device ejects a fluid containing small droplets of the second liquid that is smaller than an opening of the nozzle, whereby the fluid is injected into the liquid ejecting unit through the opening of one of the plurality of nozzles. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is injected. The product of the mass of the small droplet and the square of the flying speed of the small droplet at the opening position of the nozzle is the mass of the droplet of the first liquid ejected from the opening of the nozzle and the droplet. The liquid ejecting apparatus according to claim 7, wherein the liquid ejecting apparatus is larger than a product of a flying speed and a square. The liquid ejecting apparatus according to any one of claims 1 to 8, wherein the second liquid is pure water or a liquid containing a preservative in pure water. A common liquid chamber capable of storing a first liquid supplied via a liquid supply path, and a plurality of the first liquid supplied from the common liquid chamber and in communication with the common liquid chamber and capable of ejecting the first liquid to the medium A liquid ejecting section having a nozzle;
A fluid injecting device capable of injecting at least one of a gas and a second liquid into the liquid ejecting unit through the opening of the nozzle;
A maintenance method for a liquid ejecting apparatus comprising:
An injecting step of injecting the fluid into the liquid ejecting unit through an opening of one of the plurality of nozzles;
A discharging step of discharging the fluid containing the first liquid in the liquid ejecting unit through the openings of the other nozzles among the plurality of nozzles by the pressure of the fluid injected in the injecting step;
A maintenance method for a liquid ejecting apparatus.