JP6652185B2 - Liquid injection device - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as a printer.

  Some inkjet printers, which are examples of liquid ejecting apparatuses, discharge a cleaning agent in a mist state to nozzles for ejecting ink to dissolve solid components of ink fixed around the nozzles and near openings. After that, there is a method in which the melt is blown off by discharging a gas to remove the melt (for example, Patent Document 1).

JP 2002-178529 A

  By the way, when the nozzle is clogged, the nozzle clogging can be eliminated by vigorously introducing the droplets of the cleaning agent into the nozzle. However, if a droplet of the cleaning liquid enters a nozzle that is not clogged, a meniscus (curved liquid surface) formed in the nozzle may be broken, and the jetting performance of the nozzle may be reduced. As described above, when the maintenance of the liquid ejecting unit having the nozzle is performed by the droplet, the maintenance result is changed according to the state of the nozzle, and thus the maintenance efficiency is low.

Such problems are not limited to printers that perform printing by ejecting ink, but are generally common to liquid ejecting apparatuses that have nozzles for ejecting liquid.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid ejecting apparatus capable of efficiently performing maintenance of a liquid ejecting unit having a nozzle capable of ejecting liquid.

Hereinafter, means for solving the above problems will be described.
A liquid ejecting apparatus that solves the above-mentioned problem has a liquid ejecting unit that has a nozzle that can eject a first liquid to a medium, and can eject a fluid that includes a second liquid to a liquid ejecting surface that the nozzle opens. A fluid ejecting device having a fluid ejecting nozzle provided with an ejection port, wherein the fluid ejecting device guides the fluid ejecting nozzle so as to reciprocate along the liquid ejecting surface of the liquid ejecting unit. have, as a maintenance operation to perform maintenance of the liquid ejecting portions, the liquid ejecting surface of the nozzle of the liquid ejecting portion are open, perform fluid injection for injecting a fluid containing a second liquid, said fluid The distance between the ejection port and the liquid ejection surface in ejection is the distance between the liquid ejection surface and the medium when the liquid ejection unit ejects the first liquid to the medium in the direction of gravity. Longer.
A liquid ejecting apparatus that solves the above problem has a liquid ejecting unit that has a nozzle that can eject a first liquid to a medium, and an ejection port that can eject a fluid containing a second liquid to the liquid ejecting unit. A fluid ejecting apparatus, wherein the fluid ejecting apparatus performs a maintenance operation for maintaining the liquid ejecting section, with respect to an opening area where the nozzle of the liquid ejecting section is opened, the opening being smaller than the opening of the nozzle. A first fluid ejection for ejecting a fluid containing small liquid droplets of a second liquid; and a fluid containing a droplet of the second liquid having a smallest droplet larger than the small liquid droplet to the liquid ejecting unit. And second fluid ejection.

  According to this configuration, the fluid ejecting apparatus performs the first fluid ejection on the opening area, thereby introducing small droplets of the second liquid smaller than the opening of the nozzle into the nozzle, thereby preventing the nozzle from being clogged. Maintenance to resolve the problem can be performed. On the other hand, in the second fluid ejection performed by the fluid ejecting apparatus on the liquid ejecting unit, since the second liquid droplet having the smallest droplet larger than the small droplet is ejected, the droplet is less likely to enter the nozzle. Therefore, it is possible to prevent the meniscus formed in the nozzle from being broken due to the second liquid droplet entering the nozzle that is not clogged. Therefore, the maintenance of the liquid ejecting section having the nozzle capable of ejecting the liquid can be efficiently performed.

  The liquid ejecting apparatus includes a wiping member capable of wiping the liquid ejecting unit, and as the maintenance operation, after the fluid ejecting apparatus performs the second fluid ejecting on the opening area, The opening area is wiped.

  According to this configuration, the fluid ejecting device performs the second fluid ejection on the opening region, thereby performing cleaning of the opening region while suppressing the droplet of the second liquid from destroying the meniscus in the nozzle. be able to. In addition, since the fluid ejecting apparatus performs the second fluid ejection on the opening area, the second liquid adheres to the opening area of the liquid ejecting unit. The maintenance of the opening area is performed in a state where the wiping member is moistened by the second liquid attached to the ejection unit. Thereby, the frictional resistance becomes smaller than when the wiping member wipes the opening area in a dry state, so that the load applied to the opening area by the wiping operation can be reduced. Further, since the fixed matter fixed to the opening area is wetted by the second liquid by the second liquid, the fixed matter is dissolved in the second liquid, so that the foreign matter fixed to the opening area can be efficiently removed by wiping by the wiping member. .

  The liquid ejecting apparatus includes a wiping member capable of wiping the liquid ejecting unit, and when a region that does not include the opening region in the liquid ejecting unit is a non-opening region, the fluid ejecting device may be configured as the maintenance operation. After performing the second fluid ejection on the non-opening area to cause the second liquid to adhere to the liquid ejecting unit, the wiping member contacts the non-opening area, and further the wiping member contacts the non-opening area. Wiping.

  According to this configuration, the fluid ejection device performs the second fluid ejection on the non-opening region, thereby suppressing the droplet of the second liquid from destroying the meniscus in the nozzle and cleaning the non-opening region. It can be performed. Further, the wiping member contacts the non-opening area after the second fluid ejection, so that the wiping member can be wetted with the second liquid. Therefore, by the wiping member wiping the opening region thereafter, foreign matter attached to the opening region can be removed while reducing the load applied to the opening region as compared with the case where the opening region is wiped in a dry state. .

In the above liquid ejecting apparatus, the second liquid is pure water or a liquid containing a preservative in pure water.
According to this configuration, since the main component of the second liquid is pure water, even when the second liquid enters the nozzle, deterioration caused by mixing with the second liquid of the first liquid in the nozzle is prevented. Can be suppressed. Further, when the preservative is contained in pure water as a main component, it is possible to suppress the decay of the second liquid held in the fluid ejection device.

  In the above liquid ejecting apparatus, the fluid ejecting apparatus can eject a fluid including a third liquid containing a liquid repellent component, and as the maintenance operation, the fluid ejecting apparatus applies the small liquid to the liquid ejecting unit. A fluid including a droplet of the third liquid having a minimum droplet larger than a droplet is ejected.

  According to this configuration, the fluid ejecting apparatus ejects the fluid containing the third liquid containing the liquid repellent component, thereby attaching the third liquid to the liquid ejecting unit and improving the liquid repellency of the liquid ejecting unit. be able to. Then, by improving the liquid repellency of the liquid ejecting unit, the liquid ejecting unit ejects the first liquid from the nozzle toward the medium, whereby a minute mist of the first liquid is unintentionally generated. When the liquid adheres to the liquid ejecting unit, the first liquid can be prevented from sticking to the liquid ejecting unit.

  In the liquid ejecting apparatus, in the ejection direction in which the fluid ejecting device ejects a fluid from the ejection port, a distance from the ejection port to the liquid ejecting unit is smaller than a distance when the first fluid ejection is performed. It is longer when performing fluid ejection.

  According to this configuration, the distance from the ejection port to the liquid ejection unit when the fluid ejection device performs the second fluid ejection is longer than that when the first fluid ejection is performed. The flying speed of the arriving second liquid droplet becomes relatively slow. This makes it difficult for the second liquid to enter the nozzle, and even if it does, the impact when the second liquid collides with the meniscus is reduced, so that destruction of the meniscus can be suppressed. Also, if the flying speed of the droplet is high, there is a risk that the droplet collides violently with the liquid ejecting unit and scatters around. The second liquid can be efficiently attached to the liquid ejecting unit by suppressing the scattering.

  In the liquid ejecting apparatus, a direction in which the fluid ejecting apparatus ejects fluid from the ejection port in the first fluid ejection is set as a first ejection direction, and the fluid ejecting apparatus ejects fluid from the ejection port in the second fluid ejection. Assuming that the direction in which the liquid is ejected is the second ejection direction, the intersection angle of the second ejection direction with respect to the opening surface of the liquid ejecting unit where the nozzle opens is smaller than the intersection angle of the first ejection direction with respect to the opening surface.

  According to this configuration, since the intersection angle of the second ejection direction with respect to the opening surface where the nozzle is opened is smaller than the intersection angle of the first ejection direction with respect to the opening surface, the liquid of the second liquid ejected by the second fluid ejection is ejected. Drops are less likely to enter the nozzle. Therefore, destruction of the meniscus of the nozzle due to the second fluid ejection can be suppressed.

  In the liquid ejecting apparatus, the fluid ejecting apparatus 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, Assuming that the direction in which the gas is ejected from the ejection port is the gas ejection direction, the angle θ of the gas ejection direction with respect to the opening surface of the liquid ejection unit with respect to the opening of the nozzle is 0 ° ≦ θ <90 °.

  According to this configuration, since the angle of the gas ejection direction with respect to the opening surface where the nozzle opens is 0 ° ≦ θ <90 °, it is suppressed that the gas ejected from the ejection port enters the nozzle and disturbs the meniscus. You. In addition, the fluid ejecting apparatus injects gas into the liquid ejecting unit in a state where the intersection angle with respect to the opening surface is small, thereby causing the gas to flow along the opening surface and blowing off the deposits attached to the liquid ejecting unit to improve efficiency. Can be removed well.

  In the liquid ejecting apparatus, the product of the mass of the small droplet ejected from the ejection port toward the nozzle by the fluid ejecting device and the square of the flying speed of the small droplet at the opening position of the nozzle is: The liquid ejecting unit is larger than the product of the mass of the droplet of the first liquid ejected from the nozzle and the square of the flying speed of the droplet.

  The kinetic energy of the ejected droplet is determined by the product of the mass of the droplet and the square of the flying speed of the droplet at a predetermined position. The liquid ejecting unit ejects the droplet of the first liquid from the nozzle. If the kinetic energy 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 of the small droplet that the fluid ejecting device ejects from the ejection port toward the nozzle at the opening position of the nozzle is larger than the energy that ejects the first liquid droplet from the nozzle. . Therefore, clogging of the nozzle, which cannot be eliminated by the ejection operation of ejecting the first liquid droplet from the nozzle opening, is eliminated by kinetic energy when the small droplet of the second liquid ejected by the fluid ejection device enters the nozzle. can do.

  In the above liquid ejecting apparatus, the liquid ejecting unit has a pressure generating chamber communicating with the nozzle, and an actuator capable of pressurizing the pressure generating chamber, and the liquid ejecting unit generates the pressure by driving the actuator. In a state where the first liquid in the room is pressurized, the fluid ejection device performs the first fluid ejection on the opening region of the liquid ejection unit.

  According to this configuration, when the fluid ejecting apparatus performs the first fluid ejection on the opening region of the liquid ejecting unit, the actuator is driven in the liquid ejecting unit to pressurize the pressure generating chamber communicating with the nozzle. As a result, the pressure inside the nozzle is increased, and it becomes difficult for small droplets of the second liquid ejected by the fluid ejecting device to enter the inner side of the nozzle. Therefore, when the film is stretched at the opening of the nozzle in the liquid ejecting unit, the small droplet of the second liquid ejected by the fluid ejecting device collides with the film stretched at the opening of the nozzle to break the film, Foreign matter such as the broken film is prevented from entering the nozzle. Therefore, even when the droplets are ejected from the outside of the nozzle to eliminate the clogging, it is possible to suppress the droplets and foreign substances from entering the nozzle.

FIG. 2 is a schematic diagram illustrating an embodiment of a liquid ejecting apparatus. FIG. 3 is a plan view schematically showing the arrangement of components of the liquid ejecting apparatus. FIG. 4 is a bottom view of the head unit. FIG. 3 is an exploded perspective view of the head unit. FIG. 4 is a sectional view taken along line A-A ′ in FIG. 3. FIG. 3 is an exploded perspective view of a liquid ejecting unit. FIG. 3 is a plan view of the liquid ejecting unit. (A) is a cross-sectional view taken along line BB 'in FIG. 7, (b) is an enlarged view in a single-dot chain line frame on the right side in (a), and (c) is a cross-sectional view in a single-dot chain line frame on the left side in (a). Enlarged view. FIG. 2 is a plan view showing a configuration of a maintenance device. FIG. 1 is a schematic diagram illustrating a configuration of a fluid ejection device according to a first embodiment. FIG. 2 is a perspective view of the injection unit according to the first embodiment. FIG. 2 is a schematic side cross-sectional view illustrating a usage state of the injection unit according to the first embodiment. FIG. 2 is a block diagram illustrating an electrical configuration of the liquid ejecting apparatus. FIG. 2 is a schematic side cross-sectional view illustrating a usage state of the injection unit according to the first embodiment. FIG. 2 is a schematic side cross-sectional view illustrating a standby state of the injection unit according to the first embodiment. FIG. 4 is a schematic diagram illustrating a configuration of a fluid ejection device according to a second embodiment. 9 is a table showing operation modes of the fluid ejection device according to the second embodiment. Explanatory drawing of wiping performed by attaching a foamy second liquid. Explanatory drawing of capping performed by attaching a foamy second liquid. The schematic diagram which shows the nozzle after the 2nd liquid is made to adhere. FIG. 9 is an explanatory diagram of fluid injection maintenance performed by the fluid ejection device according to the second embodiment. FIG. 4 is a schematic view showing a modification of the liquid ejecting unit. FIG. 4 is a schematic view showing a modified example of a fluid ejection nozzle.

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

(1st Embodiment)
As illustrated in FIG. 1, the liquid ejecting apparatus 7 includes a transport unit 713 configured to transport the sheet-shaped medium ST supported by the support 712 in the transport direction Y along the surface of the support 712, and a transported medium ST A printing unit 720 for ejecting ink as an example of a first liquid to perform printing, and a heating unit 717 and a blowing unit 718 for drying the ink that has landed on the medium ST.

  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 (in FIG. 1, a direction perpendicular to the paper surface).

  The transport unit 713 includes a transport roller pair 714a and a transport roller pair 714b that are disposed on the upstream side and the downstream side of the support table 712 in the transport direction Y and are driven by a transport motor 749 (see FIG. 13). Further, the transport section 713 includes guide plates 715a and 715b that are disposed 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 the medium ST. I have.

  Then, 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 as the transport roller pairs 714a and 714b rotate while pinching the medium ST. In the present embodiment, the medium ST is continuously conveyed by being unwound from a roll sheet RS wound in a roll on a supply reel 716a. Then, the medium ST fed out from the roll sheet RS and continuously conveyed is printed by the printing unit 720 on which an image is printed and then wound up in a roll shape by the take-up reel 716b.

  The printing unit 720 is guided by guide shafts 721 and 722 extending along a scanning direction X which is a width direction of the medium ST orthogonal to the transport direction Y of the medium ST, and is driven by a 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, orthogonally) both the transport direction Y and the gravity direction Z.

  The liquid is supplied to the carriage 723 through two liquid ejecting units 1 (1A, 1B) that eject ink, a liquid supply path 727 that supplies ink to the liquid ejecting units 1 (1A, 1B), and a liquid supply path 727. A storage unit 730 for temporarily storing the stored ink, and a flow path adapter 728 connected to the storage unit 730 are provided. The storage section 730 is held by a storage section holder 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 direction of gravity Z.

  The storage section 730 includes a differential pressure valve 731 provided at an intermediate position of a liquid supply path 727 for supplying ink to the liquid ejecting section 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) by the liquid ejecting units 1A and 1B located on the downstream side, and is opened. When the ink is supplied from the storage unit 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 if the pressure of the ink on the downstream side increases, and allows the supply of ink from the upstream side (the storage section 730 side) to the downstream side (the liquid ejection section 1 side). And functions as a one-way valve (check valve) for suppressing the backflow of ink from the downstream side to the upstream side.

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

  The upstream end of the supply tube 727a that constitutes a part of the liquid supply path 727 is the downstream end of a plurality of ink supply tubes 726 that can be deformed following the reciprocating carriage 723, and a part of the carriage 723. Are connected via a connection portion 726a attached to the. The downstream end of the supply tube 727a 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 727a, and the flow path adapter 728.

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

  The heat generating section 717 includes a heat generating member 717a such as an infrared heater and a reflector 717b that extend in the same scanning direction X as the direction in which the support base 712 extends. The ink attached to the medium ST is heated by heat (for example, radiant heat) such as radiated infrared rays. Further, the blower 718 for drying the ink attached to the medium ST by the blower is disposed at an upper position in which the printing unit 720 in the liquid ejecting apparatus 7 can reciprocate and is spaced from the support base 712.

  At a position between the storage section 730 and the heating section 717 in the carriage 723, a heat shielding member 729 for blocking heat transfer from the heating section 717 is provided. The heat shield member 729 is formed of a metal material having good heat conductivity such as stainless steel or aluminum, and covers at least the upper surface of the storage unit 730 facing the heat generating unit 717.

  In the liquid ejecting apparatus 7, the storage unit 730 is provided at least for each ink type. Further, the liquid ejecting apparatus 7 of the present embodiment includes a storage section 730 in which the colored ink is stored, and is capable of performing color printing and monochrome printing. The ink colors of the colored inks are, for example, cyan, magenta, yellow, black, and white. Each colored ink contains a preservative.

  In addition, when the medium ST is a transparent or translucent film or a dark color medium, for example, the white ink is used for base printing (also called solid printing or solid printing) before performing color printing. Is done. Of course, the coloring ink used can be arbitrarily selected, and may be, for example, three colors of cyan, magenta, and yellow. Further, in addition to the above three colors, at least one of light cyan, light magenta, light yellow, orange, green, and gray 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 of the carriage 723 are arranged so as to be separated by a predetermined distance in the scanning direction X and to be shifted by a predetermined distance in the transport direction Y. ing. Further, a temperature sensor 711 is provided at a lower end of the carriage 723 at a position between the two liquid ejecting units 1A and 1B in the scanning direction X.

  The moving area in which the liquid ejecting units 1A and 1B can move in the scanning direction X includes a printing area PA where ink can be landed from the nozzles 21 of the liquid ejecting units 1A and 1B during printing of the medium ST, and a moving area in the scanning direction X. The liquid ejecting sections 1A and 1B include non-print areas RA and LA that are areas outside the print area PA that do not face the medium ST being transported. The area corresponding to the print area PA in the scanning direction X is a heating area HA provided with a heating section 717 for fixing the ink that has landed on the medium ST by heating.

  A region having the maximum width in the scanning direction X where 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 712 is a print region PA. I have. That is, the ink droplets ejected from the liquid ejecting units 1A and 1B to the medium ST land in the print area PA. When the printing unit 720 has the 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-print areas RA and LA exist on both sides (the right and left sides in FIG. 2) of the print area PA in the scanning direction X. In FIG. 2, a fluid ejection device 775 for performing maintenance of the liquid ejection unit 1 is provided in the non-print area LA located on the left side of the print area PA. 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 ejection 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 ejection 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.

<Structure of 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 color of ink (for each type of liquid).

  As shown in FIG. 3, one head unit 2 has a large number (for example, 180) of openings of nozzles 21 for ejecting ink at a fixed nozzle pitch in one direction (the transport direction Y in the present embodiment). The arrangement of the nozzles constitutes the nozzle row NL.

  In the present embodiment, one head unit 2 is provided with two nozzle rows NL arranged in the scanning direction X, so that one liquid ejecting unit 1 has two rows located close to each other in the scanning direction. A total of eight nozzle rows NL arranged at regular intervals in X are formed. When the two liquid ejecting units 1 project a large number of nozzles 21 constituting the nozzle rows NL in the scanning direction X, the two nozzles 21 may have the same nozzle pitch between the nozzles 21 at the ends. 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 body 11 and a flow path forming member 40 fixed to one surface (upper surface) of the head body 11. The head main body 11 includes a flow path forming substrate 10, a communication plate 15 provided on one surface (lower surface) of the flow path forming substrate 10, and an opposite surface (lower surface) of the communication plate 15 to the flow path forming substrate 10. , A protection substrate 30 provided on the side (upper side) of the flow path forming substrate 10 opposite to the communication plate 15, and a protection plate 30 provided on the surface of the communication plate 15 on which the nozzle plate 20 is provided. And a compliance substrate 45.

  The channel forming substrate 10 can be made of a metal such as stainless steel or Ni, a ceramic material typified by ZrO2 or Al2O3, a glass ceramic material, an oxide such as MgO or LaAlO3, or the like. In the present embodiment, the flow path forming substrate 10 is made of a silicon single crystal substrate.

  As shown in FIG. 5, a plurality of nozzles 21 for discharging ink are provided on the flow path forming substrate 10 by anisotropic etching from one surface side so that the pressure generating chambers 12 defined by the plurality of partition walls discharge ink. Are arranged side by side along the direction in which they are to be performed. The flow path forming substrate 10 is provided with a plurality of rows (two rows in the present embodiment) in which the pressure generating chambers 12 are arranged in the transport direction Y so as to be arranged in the scanning direction X.

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

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

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

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

  Further, a supply communication passage 19 communicating with one end of the pressure generation chamber 12 in the transport direction Y is provided in the communication plate 15 independently for each pressure generation chamber 12. This supply communication passage 19 communicates the second manifold section 18 with the pressure generating chamber 12.

  As such a 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 that of the flow path forming substrate 10. That is, when a material having a significantly different linear expansion coefficient from 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 the present embodiment, by using the same material as the flow path forming substrate 10, that is, a silicon single crystal substrate, as the communication plate 15, it is possible to suppress occurrence of warpage due to heat, cracks due to heat, peeling, and the like.

  The surface (lower surface) of the nozzle plate 20 from which ink droplets are ejected, that is, the surface opposite to the pressure generating chamber 12 is referred to as a liquid ejecting surface 20a, and the opening of the nozzle 21 opening to the liquid ejecting surface 20a is a nozzle. It is called an opening.

  As the nozzle plate 20, for example, a metal such as stainless steel (SUS), an organic substance such as a 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, and peeling are suppressed. can do.

  On the other hand, a vibration plate 50 is formed on the side of the flow path forming substrate 10 opposite to the communication plate 15. In the present embodiment, as the vibration plate 50, 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. I have. The liquid flow path such as the pressure generating chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one surface side (the surface side to which the nozzle plate 20 is joined). The other surface of the liquid flow path is defined by an elastic film 51.

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

  In general, one of the electrodes 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, a common electrode is provided by providing the first electrode 60 continuously over the plurality of actuators 130, and an individual electrode is provided by providing the second electrode 80 independently for each actuator 130.

  Of course, there is no problem even if this is reversed for 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, but the present invention is not limited to this. For example, any one of the elastic film 51 and the insulator film 52 may be provided as the diaphragm 50, and the first electrode may be provided without providing the elastic film 51 and the insulator film 52 as the diaphragm 50. Only 60 may act as the diaphragm. Further, the actuator 130 itself may also substantially serve as the diaphragm.

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

  Further, the second electrode 80, which is an individual electrode of the actuator 130, is pulled out from the vicinity of the end opposite to the supply communication passage 19 and extends to the diaphragm 50, for example, gold ( One ends of lead electrodes 90 made of Au) or the like are connected to each other.

  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 sheet-like material having flexibility (flexibility), for example, a COF substrate or the like can be used.

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

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

  The holding portion 31 has a concave shape that opens toward the flow path forming substrate 10 without penetrating the protection substrate 30 in the gravity direction Z that is the thickness direction. Further, the holding units 31 are provided independently for each row including 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 of the actuators 130 arranged in the scanning direction X, and the rows of the actuators 130, that is, two of the actuators 130 are arranged in the transport direction Y. Such a holding section 31 may have a space that does not hinder the movement of the actuator 130, and the space may be sealed or not sealed.

  The protection substrate 30 has a through-hole 32 penetrating in the direction of gravity Z that is the thickness direction. The through-hole 32 is provided between the two holding units 31 arranged in the transport direction Y in the scanning direction X, which is the direction in which the plurality of actuators 130 are arranged. That is, the through hole 32 is an opening having a long side in the direction in which the plurality of actuators 130 are arranged. 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 board 121 are electrically connected in the through hole 32.

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

  The head unit 2 having such a configuration includes the 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 plan view, and is joined to the protection substrate 30 and also to the communication plate 15 described above. Specifically, the flow path forming member 40 has a concave portion 41 on the side of the protection substrate 30 having a depth in which the flow path forming substrate 10 and the protection substrate 30 are accommodated. The concave portion 41 has an opening area larger than the surface of the protection substrate 30 joined to the flow path forming substrate 10. The opening surface of the concave portion 41 on the nozzle plate 20 side is sealed by the communication plate 15 in a state where the flow path forming substrate 10 and the like are accommodated in the concave portion 41. Thus, a third manifold portion 42 is defined on the outer peripheral portion of the flow path forming substrate 10 by the flow path forming member 40 and the head main body 11. 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 share the common configuration of the present embodiment. A liquid chamber 100 is configured.

  That is, the common liquid chamber 100 includes the first manifold section 17, the second manifold section 18, and the third manifold section 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 liquid chambers provided on both outer sides of the two rows of pressure generating chambers 12 are arranged. 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 the pressure generating chambers 12 (rows arranged 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 be in communication.

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

  Further, the flow path forming member 40 is provided with a connection port 43 through which the wiring board 121 is inserted in communication with the through hole 32 of the protection substrate 30. The other end of the wiring board 121 extends in the direction in which the through-hole 32 and the connection port 43 penetrate, that is, in the direction of gravity Z, and is opposite to the direction in which the ink droplets are ejected.

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

  Further, a compliance substrate 45 is provided on a 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. Then, with the compliance substrate 45 exposing the nozzle plate 20 through the first exposure opening 45a, the openings on the liquid ejecting surface 20a side of the first manifold section 17 and the second manifold section 18 are sealed. That is, the compliance substrate 45 defines a part of the common liquid chamber 100.

  In the present embodiment, such a 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 made of polyphenylene sulfide (PPS) having a thickness of 20 μm or less), and the fixed substrate 47 is made of stainless steel (SUS) or the like. Formed of a hard material such as metal. Since a region of the fixed substrate 47 facing the common liquid chamber 100 is an opening 48 completely removed in the thickness direction, one surface of the common liquid chamber 100 has a flexible sealing film 46. The compliance part 49 is a flexible part sealed only with the compliance part 49. In the present embodiment, one compliance section 49 is provided corresponding to one common liquid chamber 100. That is, in the present embodiment, since two common liquid chambers 100 are provided, two compliance portions 49 are provided on both sides of the nozzle plate 20 in the transport direction Y.

  In the head unit 2 having such a configuration, when ejecting the ink, the ink is taken in through the introduction port 44 and the inside of the flow path from the common liquid chamber 100 to the nozzle 21 is filled with the ink. Then, by applying a voltage to each actuator 130 corresponding to the pressure generating chamber 12 in accordance with a signal from the drive circuit 120, the diaphragm 50 is flexibly deformed together with the actuator 130. Thereby, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the predetermined nozzle 21.

<About the configuration of the liquid ejecting unit>
Next, the liquid ejecting section 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 a holder member that holds the head unit 2 and supplies ink to the head unit 2, It includes a held head substrate 300 and a wiring substrate 121 which is an example of a flexible wiring substrate.

FIG. 7 is a plan view of the liquid ejecting unit 1 in which the illustration of the seal member 230 and the upstream flow path member 210 is omitted.
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 as 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 serving as an ink flow path. In the present embodiment, the upstream flow path member 210 is configured by stacking 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, and the upstream flow path 500 is configured by connecting these.

  In addition, the upstream flow path member 210 is not limited to such an embodiment, and may be a single member or may be configured by two or more members. Further, the laminating 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 portion 214 on the side opposite to the downstream flow path member 220, which is connected to liquid holding means such as an ink tank or ink cartridge holding ink (liquid). In the present 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.

  The first upstream flow path member 211 is provided with a first upstream flow path 501. The first upstream channel 501 is opened at the top surface of the connection portion 214, and extends in the direction of gravity Z or a direction orthogonal to the direction of gravity Z, depending on the position of a second upstream channel 502 described later, that is, It is configured by a flow path extending in a plane including the scanning direction X and the transport 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 a surface of the first upstream flow path member 211 opposite to the connecting portion 214 and communicates with the first upstream flow path 501. On the downstream side of the second upstream flow path 502 (on the side of the third upstream flow path member 213), there is provided a first liquid reservoir 502a having a larger inner diameter and a wider width than the second upstream flow path 502.

  The third upstream flow path member 213 is provided on a side of the second upstream flow path member 212 opposite to the first upstream flow path member 211. Further, a third upstream flow path 503 is provided in the third upstream flow path member 213. An opening portion of the third upstream flow path 503 on the second upstream flow path 502 side is a second liquid storage section 503a which is widened according to the first liquid storage section 502a. A filter 216 for removing air bubbles and foreign substances contained in the ink is provided in an opening portion 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 flow path 502 (first liquid reservoir 502a) is supplied to the third upstream flow path 503 (second liquid reservoir 503a) via the filter 216.

  As the filter 216, for example, a mesh-like body such as a wire net or a resin net, a porous body, or a metal plate having fine through holes can be used. Specific examples of the mesh include a metal mesh filter and a metal fiber, for example, a SUS fine wire formed into a felt shape, a metal sintered filter obtained by compression sintering, an electroforming metal filter, an 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 at the filter opening breaks) does not vary, and a filter having a high-definition hole diameter is suitable. Further, in order to prevent foreign matter in the ink from reaching the nozzle opening, for example, when the nozzle opening is circular, it is preferable that the filtration particle size of the filter is smaller than the diameter of the nozzle opening.

  When a stainless steel mesh filter is used as the filter 216, the filter particle size of the filter is set at the nozzle opening (for example, when the nozzle opening is circular, the nozzle opening has a diameter of 20 μm to prevent foreign matter in the ink from reaching the nozzle opening. ) Is preferable, and in this case, the bubble point pressure (pressure at which the meniscus formed at the filter opening breaks) generated by the ink (surface tension 28 mN / m) is 3 to 5 kPa. It is. The bubble point pressure (pressure at which the meniscus formed at the filter opening breaks) generated by the ink when the twill tatami (filtration particle size: 5 μm) is employed is 0 to 15 kPa.

  The third upstream flow path 503 is branched into two at a downstream side (opposite to the second upstream flow path) of the second liquid reservoir 503a, and the third upstream flow path 503 is a third upstream flow path. A first discharge port 504A and a second discharge port 504B are opened on a surface of the member 213 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 the outlet 504.

  That is, the upstream channel 500 corresponding to one connection portion 214 has a first upstream channel 501, a second upstream channel 502, and a third upstream channel 503, and the upstream channel 500 is a downstream channel member. Two outlets 504 (first outlet 504A and 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 so as to communicate with a common flow path.

  Further, a third protrusion 217 protruding toward the downstream flow path member 220 is provided on the downstream flow path member 220 side of the third upstream flow path member 213. The third protrusion 217 is provided for each of the third upstream flow paths 503, and a discharge port 504 is provided at the distal end surface of the third protrusion 217 so as to open.

  The first upstream channel member 211, the second upstream channel member 212, and the third upstream channel member 213 provided with such an upstream channel 500 are integrally laminated by, for example, an adhesive or welding. ing. The first upstream flow path member 211, the second upstream flow path member 212, and the third upstream flow path member 213 can be fixed with screws, clamps, or the like. In order to prevent the ink (liquid) from leaking from the connection portion up to 503, it is preferable that the connection is made 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. Then, ink is supplied to each of the upstream flow paths 500 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 introduction ports 44 of the head unit 2.

  In the present embodiment, the configuration in which the upstream flow path 500 is branched into two at the downstream side of the filter 216 (on the downstream flow path member 220 side) is exemplified. The upstream flow path 500 may be branched into three or more. Further, one upstream flow channel 500 may not be branched downstream of the filter 216.

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

  The downstream flow path member 220 has a downstream flow path 600 serving as an ink flow path. The downstream flow channel 600 according to the present embodiment includes two types of downstream flow channels 600A and 600B having different shapes.

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

  The first accommodating portion 251 is large enough to accommodate the first downstream flow path member 240. The second storage section 252 is large enough to store four head units 2. The second storage section 252 according to the present embodiment can store four head units 2.

  The first downstream flow path member 240 has a plurality of first protrusions 241 formed on the surface 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 504A among the third protrusions 217 provided on 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 direction of gravity Z and opens on the top surface of the first protrusion 241 (the surface facing the upstream flow path member 210). I have. The third protrusion 217 and the first protrusion 241 are joined via a seal member 230, and the first discharge port 504A and the first flow path 601 communicate with each other.

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

  Further, a plurality of first insertion holes 243 through which the wiring board 121 electrically connected to the head unit 2 is inserted are formed in the first downstream flow path member 240. Specifically, each first insertion hole 243 penetrates in the direction of gravity 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. Further, 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.

  The second downstream flow path member 250 has a plurality of second protrusions 253 formed on the bottom surface of the first storage portion 251. Each of the second protrusions 253 is provided so as to face the third protrusion 217 provided with the second discharge port 504B among the third protrusions 217 provided on the upstream flow path member 210. In the present embodiment, four second protrusions 253 are provided. The second downstream flow path member 250 has a downstream flow path that penetrates in the direction of gravity Z and opens on the top surface of the second protrusion 253 and the bottom surface (the surface facing the head unit 2) of the second housing portion 252. 600B are provided. The third protrusion 217 and the second protrusion 253 are joined via a seal member 230, and the second discharge port 504B and the downstream flow path 600B communicate with each other.

  Further, the second downstream flow path member 250 has a plurality of third flow paths 603 penetrating in the direction of gravity Z. Each third flow path 603 is open on the bottom surface of the first storage part 251 and the second storage part 252. In the present embodiment, four third flow paths 603 are provided.

  On the bottom surface of the first housing portion 251 of the second downstream flow path member 250, a plurality of grooves 254 connected to the third flow path 603 are formed. The groove 254 forms a second flow path 602 by being sealed by the first downstream flow path member 240 accommodated in the first accommodation section 251. That is, the second flow path 602 is a flow path defined by the groove 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.

  Further, the second downstream flow path member 250 has 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 direction of gravity Z, and is formed so as 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 connecting 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 such a first downstream channel member 240 and a second downstream channel member 250, the second channel 602 can be easily formed in the downstream channel member 220.

  The second flow path 602 is an example of a flow path extending in the horizontal direction. The fact that the second flow path 602 extends in the horizontal direction means that the extending direction of the second flow path 602 includes a component (vector) in the scanning direction X or the transport direction Y. Since the second flow path 602 extends in the horizontal direction, the height of the liquid ejecting unit 1 in the direction of gravity 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. Therefore, the second flow path 602, which is provided in the horizontal direction (the direction orthogonal to the gravity direction Z), also crosses the gravity direction Z and the horizontal direction (the in-plane direction of the scanning direction X and the transport direction Y). Also includes those provided. In the present embodiment, the first flow path 601 and the third flow path 603 are provided along the direction of gravity Z, and the second flow path 602 is provided along the horizontal direction (the transport direction Y). Note that 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 flow paths other than the first flow path 601, the second flow path 602, and the third flow path 603 may be present. Further, the downstream flow path 600A is not configured by the first flow path 601, the second flow path 602, and the third flow path 603, but may be configured by 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, for example, along a direction intersecting with the gravity direction Z, or may connect a plurality of flow paths like the downstream flow path 600A. May be configured.

  One such downstream channel 600A and one downstream channel 600B are formed for one head unit 2. That is, the downstream flow path member 220 is provided with a set of four downstream flow paths 600A and four downstream flow paths 600B.

  Of the openings at both ends of the downstream flow path 600A, the opening of the first flow path 601 to which the first discharge port 504A communicates is defined as the first inflow port 610, and the opening of the third flow path 603 opening to the second storage 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 to which the second discharge port 504B is communicated is defined as the second inlet 620, and the opening of the downstream flow path 600B opening to the second storage portion 252 is defined as the second flow path. Two outlets 621 are provided. Hereinafter, when the downstream channel 600A and the downstream channel 600B are not distinguished, they are referred to as the downstream channel 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 the present embodiment) head units 2 are housed in the second housing part 252 of the downstream flow path member 220.

  As shown in FIG. 8, the head unit 2 is provided with two inlets 44 each. The first outlet 611 and the second outlet 621 of the downstream flow channel 600 (the downstream flow channel 600A and the downstream flow channel 600B) are provided in the downstream flow channel member 220 in accordance with the positions where the respective inlets 44 are opened. .

  The respective 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 channel 600 opened on the bottom surface of the second storage part 252. The head unit 2 is fixed to the second housing portion 252 by an adhesive 227 provided around each of the inlets 44. By fixing the head unit 2 to the second storage portion 252 in this manner, the first outlet 611 and the second outlet 621 of the downstream flow channel 600 communicate with the inlet 44, and ink is supplied to the head unit 2. It is being supplied.

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

  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 the present embodiment are arranged side by side 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 area electrically connected to the wiring board 121.

  The head substrate 300 has 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 penetrates in the direction of gravity Z and is formed so as to communicate with the first insertion hole 243 of the first downstream channel 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 direction of gravity Z. The third through-hole 301 is a hole through which the first projection 241 of the first downstream channel member 240 and the second projection 253 of the second downstream channel member 250 are inserted. 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 embodiment. For example, a common through hole into which the first protrusion 241 and the second protrusion 253 are inserted may be used as an insertion hole. That is, the head substrate 300 is formed with an insertion hole, a notch, or the like so as not to hinder connection between the downstream flow channel 600 of the downstream flow channel member 220 and the upstream flow channel 500 of the upstream flow channel 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) having liquid resistance to a liquid such as ink used in the liquid ejecting unit 1 and capable of being elastically deformed, for example, rubber or elastomer is used. it can.

  The seal member 230 is a plate-shaped member in which a communication passage 232 penetrating in the direction of gravity Z and a fourth protrusion 231 protruding toward the downstream flow passage member 220 are formed. In the present embodiment, eight communication paths 232 and fourth protrusions 231 are formed corresponding to the respective upstream flow paths 500 and downstream flow paths 600.

  An annular first concave portion 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 protrusion 231 protrudes toward the downstream flow path member 220 and is provided at a position facing the first protrusion 241 and the second protrusion 253 of the downstream flow path 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 passage 232 penetrates the seal member 230 in the direction of gravity Z, and has one end opened to the first recess 233 and the other end opened to the second recess 234. Then, the fourth protrusion is formed between the distal end surface of the third protrusion 217 inserted into the first concave portion 233 and the distal end surfaces of the first protrusion 241 and the second protrusion 253 inserted into the second concave portion 234. The part 231 is held in a state where a predetermined pressure is applied in the direction of gravity Z. Therefore, the upstream flow path 500 and the downstream flow path 600 are connected in a sealed state via the communication path 232.

  The cover head 400 is attached to the downstream passage member 220 on the second storage section 252 side (lower side). The cover head 400 is a member to which the head unit 2 is fixed and is fixed to the downstream flow path member 220, and has 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 joined to a surface of the compliance substrate 45 opposite to the communication plate 15 and seals a space of the compliance section 49 opposite to the flow path (common liquid chamber 100). By covering the compliance section 49 with the cover head 400 in this way, it is possible to prevent the compliance section 49 from being broken even when it comes into contact with the medium ST. Further, the ink (liquid) attached to the surface of the cover head 400 can be wiped with, for example, a wiper blade or the like, by suppressing the attachment of the ink (liquid) to the compliance section 49. It is possible to suppress contamination with the attached ink and the like. Although not specifically shown, the space between the cover head 400 and the compliance section 49 is open to the atmosphere. Of course, the cover head 400 may be provided independently for each head unit 2.

<About the configuration of the maintenance device>
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 the wiper unit 750, a receiving area FA provided with the flushing unit 751, and a maintenance area MA provided with the 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 arranged in the scanning direction X from the printing area PA (see FIG. 2) side. They are arranged in order.

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

  The liquid receiving portion 751a of the present embodiment is configured by a belt, and moves the belt by the power of the flushing motor 754 at a predetermined time when the amount of ink stains due to the flushing of the belt can be considered to have exceeded a specified amount. Note that flushing refers to an operation of forcibly ejecting (discharging) ink droplets from all the nozzles 21 independently 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. It has two cap portions 752a. The two cap portions 752a are configured to be movable by a power of the capping motor 755 between a contact position in contact with the liquid ejecting unit 1 at the home position HP and a retracted position away from the liquid ejecting unit 1. .

  The wiper unit 750 includes a movable housing 759 that can reciprocate on a pair of rails 758 extending in the transport direction Y by the power of the wiping motor 753. In the housing 759, a feeding shaft 760 and a take-up shaft 761, which are located at a predetermined distance from each other in the wiping direction (the 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 located 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 is pressed. A portion wound around the roller 765 forms a semi-cylindrical (convex) wiping member 750a. The wiping member 750a is in a state of being urged upward.

  The housing 759 includes a cassette accommodating the feeding roll 763 and the winding roll 764, and a wiping direction guided by a rail 758 and driven by a wiping motor 753 via a power transmission mechanism (not shown) (for example, a rack and pinion mechanism). (In this embodiment, a holder that can reciprocate in a direction along the transport direction Y). The housing 759 is moved in the transport direction Y between the retracted position shown in FIG. 9 and the wiping position at which the wiping member 750a finishes wiping the liquid ejecting unit 1 by the wiping motor 753 being driven in the normal rotation and the reverse rotation. Make one round trip.

  At this time, when the forward movement of the housing 759 is completed, the power transmission mechanism is switched to a state in which 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 to rotate in the reverse direction is used. A returning operation of the housing 759 and a predetermined amount of winding operation of the cloth sheet 762 on the winding roll 764 are performed. The two liquid ejecting sections 1A and 1B are sequentially moved with respect to the wiping area WA, and the wiping of the two liquid ejecting sections 1A and 1B by one reciprocating movement of the housing 759 is individually performed for each of the pieces moved to the wiping area WA. Done.

  The flushing unit 751 includes a drive roller 766 and a driven roller 767 which are parallel to each other in the transport direction Y, and an endless belt 768 wound between the drive roller 766 and the driven roller 767. The belt 768 has a nozzle row NL having a width equal to or more than eight (two rows × four rows) in the scanning direction X, and receives ink ejected from each nozzle 21 of the liquid ejecting units 1A and 1B. The liquid receiving portion 751a is configured. In this case, the outer peripheral surface of the belt 768 becomes a liquid receiving surface 769 for receiving ink.

  The flushing unit 751 is provided below the belt 768 with a moisturizing liquid supply unit (not shown) capable of supplying a moisturizing liquid to the liquid receiving surface 769, and a liquid for scraping waste ink and the like attached to the liquid receiving surface 769 in a moisturizing state. A scraper (not shown), and the waste ink received by the liquid receiving surface 769 is removed from the belt 768 by the liquid scraper. Therefore, the reciprocating movement of the belt 768 updates the receiving area facing the nozzle 21 on the liquid receiving surface 769.

  The cap unit 752 includes two cap portions 752a capable of forming a closed space surrounding the liquid ejection surface 20a (see FIG. 3), which is an opening region where the nozzle 21 is opened by contacting the two liquid ejection portions 1A and 1B. Have. Each cap unit 752a moves between a contact position where it 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 moisturizing cap 771 suppresses drying of the nozzles 21 by performing capping in contact with the liquid ejecting unit 1 to form a closed space surrounding two nozzle rows NL (see FIG. 3).

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

  Such suction cleaning is performed for each of the liquid ejecting units 1A and 1B by two nozzle rows NL. When the suction cleaning is performed, the ink droplets discharged from the nozzles 21 adhere to the liquid ejecting unit 1. After the suction cleaning is performed, wiping by the wiping member 750a is performed to remove the adhered droplets and the like. It is preferred to do so. Further, when the wiping member 750a performs wiping, there is a possibility that a foreign substance or an air bubble adhering to the liquid ejecting unit 1 is pushed into the nozzle 21 to break a meniscus or cause a discharge failure. Therefore, it is preferable that after the wiping is performed, the foreign matter mixed into the nozzle 21 is discharged by performing flushing, and the ink meniscus in the nozzle 21 is adjusted.

<Configuration of fluid ejection device>
Next, the configuration of the fluid ejection device 775 will be described in detail.
As shown in FIG. 10, the fluid ejection device 775 is configured to be able to eject at least one of air (gas) and a second liquid (cleaning liquid) to the liquid ejection unit 1. Then, the fluid ejecting apparatus 775 can eject a mixed fluid in which 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 used. In this embodiment, since the water-based resin ink in which the solvent of the ink is water is used, pure water is used as the second liquid. For example, when the solvent of the ink is a solvent, the ink is used as the second liquid. Preferably, the same solvent is used. Further, as the second liquid, a liquid containing a preservative in pure water may be used.

  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, a halogen-containing nitrogen-sulfur compound , 1,2-benzisothiazolin-3-one (for example, PROXEL GXL) and the like. When PROXEL is used as a preservative from the viewpoint of difficulty in foaming, the content of the second liquid is preferably 0.05% by mass 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 capable of ejecting a mixed fluid. The fluid ejection nozzle 778 is disposed so as to eject the mixed fluid in the ejection direction F (for example, in an upward direction orthogonal to the liquid ejection surface a). The fluid ejection nozzle 778 includes a liquid ejection nozzle 780 from which the second liquid is ejected in the ejection direction F, and an annular gas ejection nozzle 781 from which air is ejected in 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 in 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 the fact that the ink adheres and solidifies, and is preferably, for example, 0.4 mm or more. In the present embodiment, the opening diameter of the liquid jet nozzle 780 is set to 1.1 mm.

  Further, as the fluid ejection nozzle 778 of the present embodiment, a so-called external mixing type in which the mixing section KA where the second liquid and the air are mixed is located outside the fluid ejection nozzle 778 is employed. Therefore, the mixing section KA is constituted 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 forming 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 783a communicates with the gas injection nozzle 781.

  A pressure adjusting valve 784 for adjusting the pressure of air supplied from the air pump 782 is provided at an intermediate position 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.

  Further, a liquid supply pipe 788 that forms a liquid flow path 788a for supplying the second liquid stored in a storage tank 787 as an example of a liquid storage unit is connected to the fluid ejection nozzle 778. The liquid flow path 788a communicates with the liquid ejection nozzle 780. At the upper end of the storage tank 787, an atmosphere opening pipe 789 for opening the liquid storage space SK in the storage tank 787 to the atmosphere is provided, and the atmosphere opening pipe 789 is provided with a first solenoid valve 790 as an example of an open / close valve. I have.

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

  The storage tank 787 stores a 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 at an intermediate position of the supply pipe 792. At a position in the supply pipe 792 between the liquid supply pump 793 and the storage tank 787, a second solenoid valve 794 for opening and closing the supply pipe 792 is provided.

  As shown in FIGS. 11 and 12, the ejection unit 777 includes a base member 800 having a substantially rectangular box shape with a bottom, a support member 801 disposed in the base member 800 to support the fluid ejection nozzle 778, and a 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 individually reciprocable within the base member 800 along the transport direction Y.

  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 provided upright at an end 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 by transmitting the driving force of the cleaning motor 803 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 is attached to the case 802 as an example of a mating member that closes an upper end opening of the case 802. A rectangular through-hole 807 extending in the transport direction Y is formed at a position on the upper surface of the cover member 806 overlapping a part of the movement area of the fluid ejection nozzle 778 in the direction of gravity Z. A rectangular frame-shaped lip portion 808 surrounding the through hole 807 is provided on the upper surface of the cover member 806. A guide (not shown) for guiding the case 802 when the case 802 reciprocates along the transport direction Y is provided on a surface of the side plate 805 on the case 802 side.

  As shown in FIG. 12, the guide portion (not shown) raises the case 802 at positions corresponding to the liquid ejecting portions 1 </ b> A and 1 </ b> B, and the two nozzle lines 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 an enclosed state.

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

<Electrical configuration of liquid ejecting device>
Next, the electrical configuration of the liquid ejecting apparatus 7 will be described.
As shown in FIG. 13, the liquid ejecting apparatus 7 includes a control unit 810 that controls the liquid ejecting apparatus 7 as a whole. 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 rear side of the carriage 723 shown in FIG. 1 so as to extend along the guide shaft 722, and a fixed-pitch slit fixed to the carriage 723 and perforated in the code plate. And a sensor for detecting the light transmitted therethrough.

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

  A rotary encoder 812 is electrically connected to the control unit 810. The rotary encoder 812 includes a disc-shaped code plate attached to the output shaft of the cleaning motor 803, and a sensor that detects light transmitted through slits of a fixed pitch formed 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 moves away from 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 the clogging of each nozzle 21 based on the cycle of the residual vibration of the diaphragm 50 due to the driving of the actuator 130.

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

<Maintenance operation by maintenance device>
Next, the operation of the liquid ejecting apparatus 7 will be described focusing on a maintenance operation performed on the liquid ejecting unit 1 by the maintenance apparatus 710, in particular.

  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 moves the liquid ejecting units 1A and 1B while the printing unit 720 moves in the scanning direction X. Ink droplets are ejected from each nozzle 21 toward the surface of the medium ST. Then, the ejected ink droplet lands 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, at a predetermined time (for example, every elapse of a predetermined time within a range of 10 to 30 seconds) in order to prevent the viscosity of the ink in the nozzles 21 which do not eject ink droplets among all the nozzles 21 to be prevented. The printing unit 720 moves to the receiving area FA and performs flushing for ejecting and discharging ink droplets from all the nozzles 21.

  When a predetermined suction cleaning condition is satisfied, the control unit 810 controls the carriage motor 748 and moves the printing unit 720 to the home position HP to perform suction cleaning. In the suction cleaning, a negative pressure is applied to the inside of the suction cap 770 by driving the suction pump 773 in a state where the suction cap 770 is brought into contact with the liquid ejecting unit 1 so as to surround the nozzle row NL to form a closed space. 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 causes the wiping member 750a to perform wiping for wiping the liquid ejecting unit 1. The droplets and the like attached to 1 are removed. After the execution of the wiping, the control unit 810 moves the printing unit 720 to the receiving area FA and performs flushing toward the liquid receiving unit 751a to adjust the meniscus in the nozzle 21.

  After that, the control unit 810 detects the clogging of each nozzle 21 based on the cycle of the residual vibration of the diaphragm 50 due to the driving of the actuator 130. Here, the detection of the clogging of each nozzle 21 after the completion of the suction cleaning is particularly performed by using a resin ink containing a synthetic resin which is cured by heating or a UV ink which is cured by UV (ultraviolet) irradiation. This is because, if used, the nozzle 21 may not be clogged even if suction cleaning is performed. The term “clogging” as used herein refers to not only a state in which the ink in the nozzle 21 is solidified and clogged, but also a situation in which the ink is solidified so as to form a film on the meniscus of the nozzle 21, and the inside of the nozzle 21 and the pressure generating chamber 12. This also includes a state in which ink cannot be normally ejected (ejected) from the nozzle 21 due to an increase in the viscosity of the ink in the nozzle communication path 16.

  Then, when the clogging of all the nozzles 21 is not detected and the print job is in the waiting state, 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 side opposite to the home position HP in the scanning direction X. By cleaning the clogged nozzle 21 with the fluid ejecting device 775, nozzle cleaning for eliminating clogging of the nozzle 21 is performed.

  When the fluid ejecting apparatus 775 performs nozzle cleaning, the positions of the clogged nozzle 21 and the fluid ejecting nozzle 778 are adjusted so as to face each other in the gravity direction Z. In this case, the positioning of the clogged nozzle 21 and the fluid ejection nozzle 778 in the scanning direction X (a direction orthogonal to the direction in which the nozzle row NL extends) is performed by moving the printing unit 720, and the clogged nozzle 21 is moved. The positioning of the fluid jet nozzle 778 in the transport direction Y (the direction in which the nozzle row NL extends) between the fluid jet nozzle 778 and the nozzle 21 is performed.

  More specifically, when the clogged nozzle 21 is located in the liquid ejecting unit 1A, as shown in FIG. 12, after the printing unit 720 is aligned in the scanning direction X, the lip unit 808 is clogged. The case 802 is moved via the support member 801 so as to contact the liquid ejection surface 20a in a state surrounding the nozzle row NL including the nozzle 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 to adjust the position of the fluid ejecting nozzle 778 in the transport direction Y.

  At this time, in a normal state before the mixed fluid is ejected from the fluid ejection nozzle 778, the first solenoid valve 790 is opened to establish a communication state in which the liquid storage space SK communicates with the atmosphere, and the second solenoid valve 794 is activated. The valve has been 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 0. Preferably, the distance is 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 be -150 mm.

  Then, in a state shown in FIGS. 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 this air injection and is injected from the liquid injection nozzle 780. As a result, the air and the second liquid are mixed in the mixing section KA to generate a mixed fluid, and the mixed fluid is jetted to a partial area of the liquid jetting surface 20a including the clogged nozzle 21.

  This mixed fluid has a droplet shape smaller than the opening of the nozzle 21 (for example, when the opening of the nozzle is circular and the shape of the droplet is spherical, the diameter is 20 μm or less smaller than the opening diameter of the nozzle). A large number of second liquids (the droplets of the second liquid having a small diameter are referred to as small droplets DS, see FIG. 16) are included. At this time, the ejection speed of the mixed fluid from the fluid ejection nozzle 778 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 discharging operation or the flushing operation during printing. It is preferably equal to or higher 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 778j by the fluid ejection device 775 toward the nozzle 21 and the square of the flying speed of the small droplet DS at the opening position of the nozzle 21 is Is set to be larger than the product of the mass of the ink droplet ejected from the opening of the nozzle 21 and the square of the flying speed of the ink droplet.

  Further, the ejection of the mixed fluid including the small droplets DS by the fluid ejecting device 775 to the clogged nozzle 21 (the opening area where the nozzle 21 is opened) is performed when the ink in the pressure generating chamber 12 communicating with the clogged nozzle 21 is discharged. This is preferably performed in a state where the pressure is generated by the vibration of the vibration plate 50 driven by the actuator 130 corresponding to the pressure generating chamber 12. When the mixed fluid is ejected from the fluid ejection nozzle 778 to the clogged nozzle 21, the second liquid in the form of a droplet smaller than the opening of the nozzle 21 in the mixed fluid enters the nozzle 21 through the opening of the nozzle 21. And collides with the clogged part.

  That is, the second liquid in the form of a droplet smaller than the opening of the nozzle 21 collides with the ink solidified in the nozzle 21. At this time, the impact of the second liquid on the solidified ink destroys the solidified ink, and the clogging of the nozzle 21 is eliminated. At this time, since the ink in the pressure generating 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 generating chamber 12 It is suppressed to enter the inside of the injection unit 1A.

  When the injection of the mixed fluid from the fluid injection nozzle 778 is stopped, first, the first solenoid valve 790 is closed in a state where the mixed fluid is being injected from the fluid injection nozzle 778, so that the liquid storage space is opened. The SK is switched from a communication state communicating with the atmosphere to a non-communication state not communicating with the atmosphere. Then, the liquid storage space SK has a negative pressure, and the negative pressure causes the second liquid ejected from the liquid ejecting nozzle 780 to be drawn into the liquid flow path 788a.

  As a result, the gas-liquid interface KK of the second liquid in the liquid flow path 788a (the head surface of the storage tank 787) is located below the mixing section KA (on the side of the storage tank 787). Then, when the air pump 782 is stopped, the air is not injected from the gas injection 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 flow path 788a is located below the mixing section KA. The entry into the gas injection nozzle 781 beyond the KA is suppressed.

  Furthermore, in this case, even after the supply of air from the air pump 782 to the gas injection nozzle 781 via the liquid flow path 788a is stopped, the closed state of the first solenoid valve 790 is maintained, and the non-communication state of the liquid storage space SK is maintained. Is maintained. Unnecessary second liquid after washing the nozzle 21 and unnecessary ink washed out from the nozzle 21 flow down from the case 802 into the base member 800, and a waste liquid port (not shown) of the base member 800 From a waste liquid tank (not shown).

  When the clogged nozzle 21 is also present in the liquid ejecting unit 1B, as shown in FIG. 14, the lip 808 is clogged in the liquid ejecting unit 1B as in the case of the liquid ejecting unit 1A. The case 802 is moved via the support member 801 so as to contact the liquid ejection surface 20a in a state surrounding the nozzle row NL including the nozzle 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 while the first solenoid valve 790 is opened, and the clogging of the nozzle 21 is eliminated. I do.

  Note that the injection of the mixed fluid from the fluid injection nozzle 778 to the liquid injection 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 injected into the liquid ejecting units 1A and 1B becomes foamy and closes the opening of the nozzle 21, the bubble that closes the opening of the nozzle 21 while the injection of the mixed fluid is stopped. The mixed fluid in the shape returns to a droplet shape. For this reason, the mixed fluid that is first sprayed to the liquid ejecting units 1A and 1B and forms a foam and closes the opening of the nozzle 21 causes droplets in the mixed fluid that are later ejected to the liquid ejecting units 1A and 1B. It is possible to suppress the entry into the nozzle 21. If bubbling water containing no preservative is used as the second liquid, such bubbling is suppressed.

  Then, as shown in FIG. 15, after the cleaning of the clogged nozzles 21 of the liquid ejecting units 1A and 1B by the fluid ejecting device 775 is completed, the support member is in a state where the mixed fluid is ejected from the fluid ejecting nozzle 778. By moving 801 to the standby position, the fluid ejection nozzle 778 faces a position on the upper wall of the cover member 806 that does not correspond to the through hole 807. 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 hits the upper wall of the cover member 806 and flows along the upper wall, so that the air is injected from the annular gas injection nozzle 781. The pressure inside the air, that is, the pressure above the liquid jet nozzle 780 rises. Then, the second liquid in the liquid flow path 788a is pressed downward (toward the storage tank 787) by the increased pressure above the liquid jet nozzle 780. That is, the gas-liquid interface KK of the second liquid in the liquid flow path 788a is in a state of being pushed down far below the mixing section KA.

  When the air pump 782 is stopped in this state, the air is not injected from the gas injection 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 flow path 788a is located below the mixing section KA. The entry into the gas injection nozzle 781 beyond the KA is suppressed.

  After that, the printing unit 720 is moved to the home position HP side, and suction cleaning or flushing for discharging ink from the openings of the nozzles 21 of the liquid ejecting units 1A and 1B is performed, so that the printing unit 720 enters the liquid ejecting units 1A and 1B. The remaining second liquid and air bubbles are removed. The suction cleaning and flushing at this time can be performed with a small amount of ink discharged (consumed). This is because the mixed fluid was injected to the clogged nozzle 21 while the ink in the pressure generating chamber 12 communicating with the clogged nozzle 21 was pressurized as described above. This is because entering (backflow) into the interior of the liquid ejecting units 1A and 1B via the generation chamber 12 is suppressed.

(2nd Embodiment)
Next, a second embodiment of the liquid ejecting apparatus will be described with reference to the drawings.
In the second embodiment, the components denoted by the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and a 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 775D provided in the liquid ejecting apparatus of the present embodiment is configured such that the direction in which the fluid ejecting nozzle 778 ejects the fluid can be changed. Here, the position of the fluid ejection nozzle 778 when ejecting the fluid 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. Further, the position of the fluid ejection nozzle 778 when ejecting the fluid in the second ejection direction S2 obliquely intersecting the liquid ejection surface 20a is referred to as a second position P2, and the second position P2 is parallel to the liquid ejection surface 20a. The position of the fluid ejection nozzle 778 when ejecting the fluid in the three ejection directions S3 is referred to as a third position P3.

  In the fluid ejection device 775D, a liquid tank 832 is connected via a supply pipe 831 to a liquid supply pipe 788 that supplies the second liquid to the fluid ejection nozzle 778. The liquid tank 832 stores a surfactant. When the supply pipe 831 is opened, the liquid tank 832 and the liquid supply pipe 788 are in communication with each other. When the supply pipe 831 is closed, the liquid tank 832 and the liquid supply pipe 788 are not in communication. Is provided. Then, when the fluid mixture is ejected from the fluid ejection nozzle 778 when the on-off valve 833 is in the open state, 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 ejection device 775D, by opening the on-off valve 833, the fluid ejection nozzle 778 ejects the mixed fluid of the gas, the second liquid, and the surfactant.

  Further, the liquid ejecting apparatus of 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 having a downstream end connected to the air pump 782B, a storage tank 787B, a liquid supply pipe 788B having a downstream end connected to the storage tank 787B, and a gas supply pipe 783B. And a fluid injection nozzle 778B to which an upstream end of the liquid supply pipe 788B is connected. The third liquid containing the lyophobic component is stored in the storage tank 787B of the fluid ejection device 775B.

  The fluid ejection device 775B only needs to be capable of ejecting a fluid including the third liquid containing a lyophobic component, and may have the same configuration as the fluid ejection device 775 of the first embodiment, or may have one configuration. The unit may be changed. The fluid ejection device 775B is disposed, for example, in the non-printing area LA or the non-printing area RA, and can eject the fluid in the second ejection direction S2 obliquely intersecting the liquid ejection 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 focusing on a maintenance operation performed by the maintenance apparatus 710 on the liquid ejecting unit 1.

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

  As shown in FIG. 17, in the nozzle cleaning in the first mode, as described in detail in the first embodiment, in order to eliminate clogging of the nozzle 21, an opening area where the nozzle 21 is opened (the liquid ejection surface). 20a), the fluid ejection nozzle 778 performs a first fluid ejection in which a fluid including a small droplet DS of the second liquid smaller than the opening of the nozzle 21 is ejected. That is, in the first mode, the fluid ejection nozzle 778 is arranged at the first position P1 and the on-off valve 833 is closed, and the mixed fluid of the second liquid and gas is targeted at the specific nozzle 21 where clogging has occurred. Injects for a short time in the first injection direction S1 at high speed and high pressure.

  Next, in the liquid ejecting surface cleaning in the second mode, the fluid ejecting nozzle 778 moves the liquid ejecting surface 20a of the liquid ejecting unit 1 so that the fluid ejecting nozzle 778 is smaller than the small droplet DS in order to clean the liquid ejecting surface 20a. A second fluid ejection is performed for ejecting a fluid including a large liquid droplet DL of a large second liquid (when the liquid droplet is spherical). 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 ejection nozzle 778 is arranged at the second position P2, the on-off valve 833 is closed, and the mixed fluid of the second liquid and gas is targeted at a portion of the liquid ejection surface 20a where the nozzle 21 does not open. Injection is performed at a lower speed and lower pressure than the first mode in the second injection direction S2 for a predetermined time.

  That is, the direction in which the fluid ejection device 775D ejects the fluid from the ejection port 778j in the first fluid ejection is referred to as the first ejection direction S1, and the direction in which the fluid ejection device 775D ejects the fluid from the ejection port 778j in the second fluid ejection is the first direction. Assuming the two ejection directions S2, the intersection angle of the second ejection direction S2 with the liquid ejection surface 20a is preferably smaller than the intersection angle of the first ejection direction S1 with the liquid ejection surface 20a. This makes it difficult for the fluid ejected by the fluid ejection nozzle 778 to enter the nozzle 21, so that the meniscus of the ink formed in the nozzle 21 is less likely 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, but it takes time or consumes ink to adjust the meniscus. 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 determined by the first fluid ejection. If it is longer than when performing, 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 from the fluid ejection nozzle 778 enters the nozzle 21, the meniscus of the ink formed in the nozzle 21 is hard to break.

  Here, in a case where the deposit such as ink attached to the liquid ejecting surface 20a is solidified, if the wiping member 750a wipes the liquid ejecting surface 20a, the solidified material may slide on the liquid ejecting surface 20a. There is. In addition, the liquid ejecting surface 20a is often subjected to a liquid repellent treatment for improving liquid repellency, such as forming a liquid repellent film by applying a liquid repellent agent, in order to suppress adhesion of ink droplets. Therefore, when the wiping member 750a wipes the liquid ejecting surface 20a to which the solidified material adheres, the solidified material is dragged and the liquid repellent film may be damaged, and the liquid repellent effect may be reduced. In that regard, in the maintenance of the second mode performed by the fluid ejecting apparatus 775D, the liquid ejecting surface 20a is washed with the second liquid, so that the foreign matter (ink) adhering to the liquid ejecting surface 20a is not damaged to the liquid repellent film. And dust) can be removed.

  In addition, if the wiping member 750a wipes the liquid ejecting surface 20a, foreign matters and bubbles adhering to the liquid ejecting surface 20a may be pushed into the nozzle 21 and may result in defective ejection of liquid droplets. On the other hand, when the second liquid is jetted to the liquid jetting surface 20a for cleaning, foreign matter is not pushed into the nozzle 21, which is preferable.

  The wiping member 750a may perform wiping 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 apparatus 775D ejects the fluid to the opening area (the liquid ejecting surface 20a) where the nozzle 21 is opened in the liquid ejecting section 1 to attach the second liquid, and then the second liquid The opening area is wiped by the wiping member 750a moistened by contact with the wiping member. According to this configuration, the dirt adhering to the liquid ejecting surface 20a is easily dissolved and dissolved in the second liquid, and the frictional resistance of the wiping member 750a to the liquid ejecting surface 20a is reduced, so that the lyophobic film is hardly damaged. Become. In this wiping, since the second liquid only needs to be attached to the liquid ejecting unit 1 or the wiping member 750a, the wiping is not limited to the second fluid ejecting, and the fluid ejecting device 775, 775D may be used for the liquid ejecting unit 1 or the wiping prior to the wiping. The second liquid or a mixed fluid containing the second liquid may be jetted toward the member 750a.

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

  Next, in the gas blowing in the third mode, the liquid jetting surface 20a of the liquid jetting unit 1 is applied to the liquid jetting surface 20a for the purpose of removing foreign substances (particularly, unsolidified ink droplets and dust) attached to the liquid jetting surface 20a. , The fluid ejection nozzle 778 performs ejection of only gas. That is, the fluid ejection 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. Foreign matter adhering to the surface 20a is blown off.

  Assuming that 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 °. When the angle θ of the third ejection direction S3 with respect to the liquid ejection surface 20a is small (for example, θ = 0 °) and the possibility that the ejected gas disturbs the meniscus of the nozzle 21 is small, it is preferable to eject the gas at high speed and high pressure. However, since the foreign matter removal efficiency is high, it is preferable.

  In other words, if the ejection direction of the gas from the fluid ejection nozzle 778 is the third ejection direction S3, the gas ejected from the fluid ejection nozzle 778 is unlikely to enter the nozzle 21, so that the meniscus of the ink 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 slidably contact the liquid ejecting surface 20a, foreign matter (such as ink and dust) attached to the liquid ejecting surface 20a by blowing air is removed without damaging the liquid repellent film. It becomes possible.

  In addition, since the removal of the foreign matter by the gas ejection can be performed in a shorter time than the wiping performed by moving the wiping member 750a, for example, the liquid ejecting unit 1 is periodically turned off during the printing operation in the printing area PA. It is possible to perform maintenance that moves to the printing area LA and removes ink droplets and the like adhering to the liquid ejecting surface 20a by blowing them off with a gas. In addition, in the case of gas ejection, it is also possible to remove foreign matter adhering 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).

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

  Next, in the foam attachment in the fourth mode, the fluid ejection nozzle 778 moves the gas, the second liquid, and the surfactant in the second ejection direction S2 in order to attach the foamy second liquid to the liquid ejection unit 1. Is injected. In the fourth mode, the fluid ejecting nozzle 778 is arranged at the first position P1, and the on-off valve 833 is opened, and the second liquid ejected from the fluid ejecting nozzle 778 is mixed with a surfactant, and the fluid is ejected in the first ejecting direction S1. The second liquid is foamed by causing the ejected fluid to collide with the liquid ejection surface 20a or the non-open area (for example, the portion of the cover head 400) for a predetermined time. In the fourth mode, foaming of the liquid is promoted by mixing a surfactant with the second liquid ejected from the fluid ejection nozzle 778.

  The mixing ratio between the second liquid and the surfactant can be adjusted by changing the head difference between the second liquid in the storage tank 787 and the surfactant in the liquid tank 832. Further, in the fourth mode, similarly to the second mode, when the fluid including the large droplet DL of the second liquid having the minimum droplet diameter larger than the small droplet DS is ejected at a lower speed and a lower pressure than the first mode, the nozzle This is preferable because it hardly disturbs the meniscus of No. 21. In the fourth mode, the second liquid can be efficiently foamed by continuing the injection of the fluid containing the second liquid for a longer time than the fluid injection as the nozzle cleaning in the first mode. .

  In the fluid ejecting apparatus 775 of the first embodiment, when a liquid obtained by adding a preservative to pure water is used as the second liquid, the liquid ejecting unit 1 is operated by the action of the component contained in the preservative. In some cases, the second liquid that has collided with the liquid may be foamed. Therefore, in such a case, the surfactant need not be mixed with the second liquid to be jetted.

  Then, as shown in FIG. 18, after the fluid ejecting device 775D attaches the foam BU (the 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 wiping area. That is, the fluid ejecting device 775D functions as a liquid attaching device that attaches the foamy second liquid to the liquid ejecting unit 1. This is preferable because the frictional resistance when the wiping member 750a slides on the liquid ejecting surface 20a is reduced by the bubble BU, and the liquid repellent film is less likely to be damaged. Note that, in the present embodiment, an elastically deformable plate-like member is illustrated as the wiping member 750B that performs wiping, but the same applies to the wiping member 750a made of a cloth sheet described in the first embodiment. Action can be obtained.

  Assuming that a portion to be wiped by the wiping member 750 </ b> B of the liquid ejecting unit 1 is a wiping region, the wiping region includes an opening region (the liquid ejecting surface 20 a) where the nozzle 21 is opened in the liquid ejecting unit 1 and an outside of the opening region including the opening region. And a non-open area (cover head 400). That is, it is preferable that the wiping member 750B wipes not only the liquid jetting surface 20a but also the portion of the cover head 400 outside the liquid jetting surface 20a. The area where the fluid ejecting apparatus 775D adheres the foam 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 bringing the moisturizing cap 771 or the suction cap 770 into contact with the cover head 400 which is a non-opening area, when the caps 770 and 771 contact the liquid ejecting unit 1. In some cases, the liquid adhering to the liquid ejecting unit 1 may collect 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 by the release of the 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 is performed after the contact area where the caps 770 and 771 come into contact with each other when the capping is performed is included in the wiping area, and the fluid ejecting device 775D attaches the foam BU (the foam-like second liquid) to the contact area. This is preferable because contact traces can be removed.

  In addition, as shown in FIG. 19, in a state where the fluid ejecting apparatus 775 </ b> D causes the droplets or bubbles BU of the second liquid to adhere to the liquid ejecting unit 1 by ejecting the mixed fluid in the first, second, or fourth mode. The moisturizing cap 771 may be brought into contact with the liquid ejecting unit 1 to perform capping so that the attached second liquid is included in the closed space. With this configuration, 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 or the moisturizing time can be increased. Or become possible.

  In this case, the fluid ejection device 775D functions as a liquid attachment device that attaches the second liquid to the liquid ejection unit 1. In the fluid ejection device 775D, by mixing and ejecting a gas with the second liquid, the diameter of the droplet of the second liquid can be reduced, and the flying speed of the droplet and 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, the gas need not be mixed with the fluid to be ejected, and the second liquid is ejected as droplets. You don't have to.

  Here, when the fluid ejected by the fluid ejecting device 775D vigorously collides with the liquid ejecting unit 1 at an angle close to a right angle, when the fluid collides with the liquid ejecting unit 1, the fluid collides easily and scatters around. In this regard, by reducing the intersection angle between the fluid ejection direction F and the liquid ejecting unit 1, scattering of the fluid when it contacts the liquid ejecting unit 1 is suppressed, and the second liquid is efficiently dispensed from the liquid ejecting unit 1. Can be adhered to. Therefore, it is preferable to eject the fluid in the second ejection direction S2 in order to cause the liquid ejecting unit 1 to adhere the droplets of the second liquid. On the other hand, in order to foam the second liquid in the liquid ejecting unit 1, it is preferable to inject the mixed fluid in the first ejection direction S1 with the second liquid containing gas.

  As shown in FIG. 19, when the second liquid is attached to the liquid ejecting unit 1 before the capping is performed by bringing the moisturizing cap 771 into contact with the cover head 400 which is a non-opening area, the cover head 400 It is preferable that the fluid ejection device 775D ejects the second liquid toward the nozzle 21 because the meniscus of the nozzle 21 is not broken by the ejected second liquid. On the other hand, if the second liquid is made 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 750B performs wiping after the execution of the first fluid ejection or the like by the fluid ejection device 775D to clean the liquid ejection unit 1, the fluid ejection device 775D performs the second fluid ejection or the like. It is preferable that the moisturizing cap 771 performs capping when the second liquid is attached to the liquid ejecting unit 1 by execution. That is, the foreign matter adhering to the liquid ejecting unit 1 is removed by removing the foreign matter adhering to the liquid ejecting unit 1 by performing wiping in a state of being wetted with the second liquid, so that the foreign matter adhering to the liquid ejecting unit 1 during capping is removed. Can be prevented from sticking.

  As shown in FIG. 20, when the foam-like second liquid is attached to a position close to the nozzle 21, after the bubble BU disappears, a film Me of the second liquid is formed on the meniscus surface Sf of the nozzle 21. The film Me functions as a drying prevention film. Therefore, when capping is performed for a long time or when the environmental temperature is high, capping may be performed in a state in which the foam-like second liquid is attached to the liquid ejection surface 20a. In addition, when performing capping for a long time, if the foam BU formed by mixing a surfactant with the second liquid and foaming is adhered, the foam BU is less likely to be broken by the action of the surfactant. The two-liquid foam BU can be kept near the nozzle 21 for a longer time.

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

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

  Further, the liquid ejecting surface 20a preferably has high liquid repellency in order to suppress adhesion and solidification of ink droplets. However, 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. By doing so, it is possible to hold the second liquid for moisturizing in the cover head 400 while suppressing the attachment of the liquid droplets to the liquid ejecting 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, the evaporation or volatilization of the dispersion medium or the solvent (eg, water or the like) contained in the ink or the like suppresses the drying of the nozzle 21 opened in the moisturizing cap 771. In addition, a roller or the like for attaching a liquid for moisturizing to the liquid ejecting unit 1 may be separately provided.

  When capping is performed by bringing the suction cap 770 into contact with the cover head 400, it is preferable that the liquid adhering to the liquid ejecting unit 1 after the suction cleaning is quickly moved to the suction cap 770 side. Therefore, in particular, the lip portion of the suction cap 770 that comes into contact with the cover head 400 is preferably set to have a lower liquid repellency than the cover head 400.

  Next, in the lyophobic processing of the fifth mode, when the lyophobic film is damaged, for example, the fluid ejecting device 775B uses the liquid ejecting surface 20a as a maintenance operation for restoring the lyophobic performance of the liquid ejecting surface 20a. Then, a fluid including a third liquid droplet having a minimum droplet diameter larger than the small droplet DS is ejected in the second ejection direction S2. At this time, by ejecting the third liquid together with the gas, droplets of the third liquid can be diffused over a wide range. After the liquid droplets of the third liquid are attached to the liquid ejecting surface 20a, wiping may be performed to spread the third liquid uniformly 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. Discharging the fluid containing the ink in the liquid ejecting unit 1 through the opening of the other nozzle 21 among 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 through the liquid supply path 727 and the second liquid that is supplied from the common liquid chamber 100. It has a plurality of nozzles 21 that can eject one liquid to the medium. Then, the fluid ejecting device 775D injects a fluid into the liquid ejecting unit 1 through the opening of one of the plurality of nozzles 21, and sends the fluid including the first liquid (ink) out of the plurality of nozzles 21. Fluid injection maintenance for discharging through the opening of the other nozzle 21 is performed. In this regard, the fluid ejection device 775D functions as a fluid injection device that can inject at least one of the gas and the second liquid into the liquid ejection unit 1 through the opening of the nozzle 21.

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

  That is, the fluid ejection device 775D functioning as a fluid injection device has an ejection port 778j capable of ejecting the second liquid, and ejects a fluid from the ejection port 778j when the ejection port 778j is separated from the liquid ejection unit 1. By doing so, the 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 together with foreign matter from the other nozzles 21 (discharge step). Examples of the foreign matter mixed in the common liquid chamber 100 include, in addition to air bubbles, fragments of a film (solidified ink) that has been destroyed due to the nozzle cleaning in the first mode and has entered the inner side of the nozzle 21. Is mentioned.

  The sixth mode is the same as the first mode except that the injection time is longer than the first mode. Therefore, the injection time of the fluid injection for nozzle cleaning in the first mode is the same. , The fluid ejection in the first mode and the sixth mode can be continuously executed. In this case, the fluid injection device (fluid ejection device 775D) ejects a fluid including the small droplet DS of the second liquid having a smaller diameter than the opening diameter of the nozzle 21, thereby forming one of the plurality of nozzles 21. The fluid is injected into the liquid ejecting unit 1 through the opening of the nozzle 21.

  In the injection step, a differential pressure valve 731 (one-way valve) is opened upstream of the common liquid chamber 100 when the pressure in the liquid chamber becomes lower than the pressure in the space outside the liquid chamber by a predetermined pressure (for example, 1 kPa). Since the fluid injected from the nozzle 21 does not flow backward to the upstream side, 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 is provided with the differential pressure valve 731 functioning as a supply regulating unit capable of regulating the flow of the liquid, the fluid ejecting device 775D operates in a state where the differential pressure valve 731 regulates the flow of the liquid upstream. Preferably, fluid injection maintenance is performed. For example, in the case where an on-off valve that can be arbitrarily opened and closed is provided instead of the differential pressure valve 731, it is preferable to perform the fluid injection maintenance with the on-off valve closed.

  Further, in the liquid supply path 727, since the filter 216 is provided between the common liquid chamber 100 and the differential pressure valve 731, even if the fluid is injected into the nozzle 21, foreign matter (such as fragments of a film) is caused by the flow. 2 The flow into 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 a nozzle 21 different from the nozzle 21 into which the fluid is injected may be driven. In the nozzle 21 into which the fluid is not injected, even if the pressure in the common liquid chamber 100 slightly fluctuates, the ink does not leak from the nozzle 21 if the pressure fluctuation is within the meniscus pressure resistance range. Even in such a configuration, since the ink is pushed out from the nozzle 21 by driving the actuator 130 to press the pressure generating chamber 12 communicating with the nozzle 21, the meniscus is broken and the liquid flows out from the nozzle 21. be able to.

  Here, foreign matters such as filtered solids 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 storage portion 503a to the first liquid storage portion 502a, so that the foreign matter attached to the upstream surface of the filter 216 is separated from the filter 216. It is expected to be.

  Accordingly, it is possible to remove the deposits on the filter 216 that cannot be removed by the downstream flow, such as suction cleaning, by suction cleaning performed subsequent to 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 regulated by the differential pressure valve 731, the flow is changed by the bending displacement of the wall surface. Since the amount of liquid flowing from the second liquid storage part 503a to the first liquid storage part 502a flows, it is highly possible that the attached matter is 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 at one end side (left end side in FIG. 21) in the longitudinal direction of the common liquid chamber 100 is used. It is preferable that the fluid is injected from the nozzle 21 and the liquid is discharged from the nozzle 21 on the other end (the right end in FIG. 21).

  In the sixth mode, since it is sufficient that foreign matter can be discharged into the liquid ejecting unit 1, any fluid among gas, second liquid, or a mixed fluid of gas and second liquid may be ejected. Then, regardless of which fluid is ejected, a fluid different from the ink (first liquid) is mixed into the liquid ejecting unit 1. Therefore, after performing the maintenance in the sixth mode, the suction cap 770 is performed. Then, suction cleaning using the suction pump 773 is performed, and the fluid mixed by filling the nozzle 21 with the first liquid may be discharged from the liquid ejecting unit 1. That is, after the fluid ejecting device 775D performs the 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 passage 727 is in a state where the regulation is released by the differential pressure valve 731. To supply the first liquid 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 every time the medium ST is transported by a predetermined amount. Good. Alternatively, the state of the opening surface (liquid ejection surface 20a) is detected by a sensor or the like, and a mode is selected according to the detection state, such as selecting the second mode when foreign matter is attached to the liquid ejection surface 20a. The maintenance may be performed selectively.

According to the above embodiment, the following effects can be obtained.
(1) In the first mode, the fluid ejection device 775D performs the first fluid ejection on the opening area, thereby introducing the small droplet DS of the second liquid smaller than the opening of the nozzle 21 into the nozzle 21. In addition, nozzle cleaning as 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 ejection device 775D on the liquid ejection unit 1, the droplet DL of the second liquid having the smallest droplet larger than the small droplet DS is ejected. The droplet DL does not easily enter the nozzle 21. Therefore, in the second mode, the meniscus formed in the nozzle 21 is prevented from being broken 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 nozzle 21 capable of ejecting the liquid can be efficiently performed.

  (2) In the second mode, the fluid ejection device 775D performs the second fluid ejection on the opening area, thereby suppressing the droplet DL of the second liquid from destroying the meniscus in the nozzle 21 and opening the fluid. Area cleaning can be performed. In addition, the second liquid is attached to the opening area of the liquid ejecting unit 1 by performing the second fluid ejection to the opening area by the fluid ejecting apparatus 775D. Therefore, after that, the wiping member 750B performs wiping of the opening area, so that maintenance (wiping) of the opening area is performed in a state where the wiping member 750B is wetted by the second liquid attached to the liquid ejecting unit 1. Accordingly, the frictional resistance is smaller than when the wiping member 750B wipes the opening area in a dry state, and thus the load applied to the opening area by the wiping operation can be reduced. In addition, since the fixed matter fixed to the opening area is wetted by the second liquid by the second liquid, the fixed matter is dissolved in the second liquid, so that the foreign matter fixed to the opening area can be efficiently removed by wiping by the wiping member 750B. it can.

  (3) In the second mode, the fluid ejection device 775D performs the second fluid ejection on the non-open area, thereby suppressing the droplet DL of the second liquid from destroying the meniscus in the nozzle 21, Cleaning of the non-open area can be performed. Further, since the wiping member 750B comes into contact with the non-opening area after the second fluid ejection, the wiping member 750B can be wet with the second liquid. Therefore, the wiping member 750B subsequently wipes the opening area, thereby reducing the load applied to the opening area and removing foreign substances adhering to the opening area as compared with the case of wiping the opening area in a dry state. it can.

  (4) By using pure water as the main component of the second liquid, even when the second liquid enters the nozzle 21, deterioration due to mixing with the second liquid of the first liquid in the nozzle 21 is suppressed. can do. Further, when the preservative is contained in pure water as a main component, decay of the second liquid held in the fluid ejection device 775, 775D can be suppressed.

  (5) The fluid ejecting apparatus 775B ejects the fluid containing the third liquid containing the liquid repellent component, thereby causing the third liquid to adhere 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. However, 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 to the liquid ejection unit 1 when the fluid ejection device 775D performs the second fluid ejection in the second mode is longer than when performing the first fluid ejection 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 becomes relatively slow. This makes it difficult for the second liquid to enter the nozzle 21 and, even if it does, the impact when the second liquid collides with the meniscus is reduced, so that the destruction of the meniscus can be suppressed. Also, if the flying speed of the droplet is high, there is a risk that the droplet collides vigorously with the liquid ejecting unit 1 and scatters around. However, by reducing the flying speed of the droplet, the droplet contacts the liquid ejecting unit 1. The second liquid can be efficiently attached to the liquid ejecting unit 1 while suppressing scattering at the time.

  (7) Since the intersection angle of the second ejection direction S2 with 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 the opening surface, ejection is performed by the second fluid ejection. The liquid droplet DL of the second liquid is unlikely to enter the nozzle 21. Therefore, in the second mode, the meniscus of the nozzle 21 can be prevented from being broken by the second fluid ejection.

  (8) Since the angle of the gas ejection direction (third ejection direction S3) with respect to the opening surface (liquid ejection surface 20a) where the nozzle 21 opens is 0 ° ≦ θ <90 °, the gas ejected from the ejection port 778j is Disturbing the meniscus by entering the nozzle 21 is suppressed. Further, the fluid ejecting apparatus 775D ejects the gas to the liquid ejecting section 1 in a state where the angle with respect to the opening face is reduced, so that the gas flows along the opening face and blows off the deposit attached to the liquid ejecting section 1. And can be efficiently removed.

  (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 droplet of the first liquid ejected from the nozzle 21 by the liquid ejecting unit 1 is large, even if the nozzle 21 is slightly clogged, the clogging of the nozzle 21 is performed by the energy of the droplet. Can be eliminated. On the other hand, if the nozzle 21 is severely clogged, the clogging cannot be eliminated by the energy for ejecting the first liquid droplets from the nozzle 21. In this regard, 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 by the fluid ejection device 775D toward the nozzle 21 causes the droplet of the first liquid to be ejected from the nozzle 21. Greater than the energy to be injected. Therefore, clogging of the nozzle 21 that cannot be eliminated by the ejection operation of ejecting the first liquid droplet from the opening of the nozzle 21 is prevented when the small droplet DS of the second liquid ejected by the fluid ejection device 775D enters the nozzle 21. Can be eliminated by the kinetic energy.

  (10) When the fluid ejection device 775 </ b> D performs the first fluid ejection on the opening area of the liquid ejection unit 1, the actuator 130 is driven in the liquid ejection unit 1 to move the inside of the pressure generation chamber 12 communicating with the nozzle 21. By applying pressure, the pressure in the nozzle 21 increases. Then, it becomes difficult for the small droplet DS of the second liquid ejected by the fluid ejecting device 775D to enter the inner side of the nozzle 21. Therefore, when the film is stretched over the opening of the nozzle 21 in the liquid ejecting unit 1, the small droplet DS of the second liquid ejected by the fluid ejecting apparatus 775D collides with the film stretched over the opening of the nozzle 21 to form the film. While being destroyed, foreign matter such as the destroyed film is suppressed from entering the nozzle 21. Therefore, even when the droplets are ejected from the outside of the nozzle 21 to eliminate the clogging, it is possible to prevent the droplets and foreign substances from entering the nozzle 21.

  (11) Before the cap 771 performs capping, the liquid applying device (fluid ejecting device 775D) attaches the second liquid to the liquid ejecting unit 1. Therefore, when the cap 771 performs capping to form a closed space. The second liquid can be made to exist near the nozzle 21. Therefore, the second liquid that evaporates near the nozzle 21 can efficiently keep the nozzle 21 moist.

  (12) Since the second liquid can be attached to the liquid ejecting unit 1 by ejecting the second liquid from the ejection port 778j by the liquid attaching device (fluid ejecting device 775D), the liquid attaching device (775D) is located at a position away from the liquid ejecting unit 1. A fluid ejection device 775D can be provided.

  (13) By mixing a gas with the second liquid ejected by the liquid adhering device (fluid ejecting device 775D), the second liquid can be made to fly into finer droplets. By ejecting such minute droplets, the second liquid can be uniformly attached to a predetermined area of the liquid ejecting unit 1.

  (14) If the second liquid adheres to the opening area where the nozzle 21 opens, there is a possibility that the second liquid enters the nozzle 21 and mixes with the first liquid. In this regard, if the second liquid is allowed to adhere to the non-opening area of the liquid ejecting unit 1 that does not include the open area, it is possible to prevent the second liquid from entering the nozzle 21.

  (15) The liquid attachment device (fluid ejection device 775D) ejects the small droplet DS of the second liquid to the opening area, thereby introducing the small droplet DS into the nozzle 21 and clogging the nozzle 21. Nozzle cleaning, which is maintenance for solving the problem, can be performed. At this time, since the second liquid that has not entered the nozzle 21 adheres to the opening area, capping is performed so that the enclosed second liquid is included in the closed space, so that the second liquid is consumed for moisture retention. The moisturizing of the nozzle 21 can be performed without performing an operation for separately adhering the second liquid to the liquid ejecting unit 1, and thus the efficiency is high.

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

  (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, thereby dissolving the foreign matter adhering to the wiping area into the second liquid and efficiently removing the foreign matter. Can be removed. Further, by making the second liquid foamy, the frictional resistance when the wiping member 750B comes into contact with the wiping area is reduced. Therefore, when the wiping member 750B wipes the liquid ejecting unit 1, the liquid ejecting unit 750B is used. 1 can be reduced.

  (18) In the fluid ejecting apparatus 775D, the gas ejected from the ejection port 778j can contain gas by mixing the gas with the second liquid. The two liquids can be efficiently foamed.

  (19) In the nozzle cleaning in the first mode, it is possible to introduce small droplets DS into the nozzles 21 and eliminate the clogging. In the nozzle cleaning, the second liquid is prevented from becoming foamy by shortening the duration of time for injecting the fluid, so that the bubbles do not make it difficult for the small droplet DS to enter the nozzle 21. On the other hand, in the fourth mode, since the second liquid can be made into a foam by extending the ejection duration time of ejecting the fluid, the liquid deposition device (fluid ejection device 775D) for cleaning the nozzle can be used in the fourth mode. The two liquids can also be used as a device for foaming.

  (20) The wiping target area to be wiped includes the 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 near 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 this regard, when the liquid applying device (fluid ejecting device 775D) adheres the foamy second liquid to the non-opening region located outside the opening region, 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 collects at the contact portions with the caps 770 and 771, so that the caps 770 and 771 eject the liquid. After leaving the unit 1, contact marks of the caps 770 and 771 may remain on the liquid ejecting unit 1. In this regard, the liquid ejecting device (fluid ejecting device 775D) attaches the foamy second liquid to an area including the contact area where the caps 770 and 771 come into contact, and the wiping member 750B wipes the area to thereby eject the liquid. 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 the halogen-containing nitrogen-sulfur compound contained in the second liquid, decay of the second liquid can be suitably suppressed. .

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

  (25) When the fluid regulating unit (differential pressure valve 731) regulates the flow of the liquid at the time of executing the fluid injecting maintenance, the fluid injected by the fluid injecting device (fluid ejecting device 775D) from the nozzle 21 moves 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 to the opening of the nozzle 21 after the fluid injection maintenance, the fluid ejecting device is replaced with the first liquid to be filled. Since the second liquid injected by the nozzle 775D from the nozzle 21 is discharged, foreign substances in the common liquid chamber 100 can be discharged together with the second liquid. Further, 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 follows the flow of the fluid injected from the nozzle 21 by the filter 216 located between the supply regulating unit (differential pressure valve 731) and the common liquid chamber 100, and the foreign matter of the differential pressure valve 731 It can be suppressed from flowing to the side. Further, by applying pressure from the downstream side of the filter 216 to the fluid injected from the nozzle 21, solids and the like accumulated on the upstream side of the filter 216 can be peeled off from the filter 216.

  (28) When the fluid injection maintenance is performed, the fluid injection device (fluid injection 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 nozzle 21 can receive the fluid. 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 for the first liquid ejected by the liquid ejection unit 1 is provided. 778j can be suppressed.

  (30) When the fluid injection device (fluid ejection device 775D) ejects a fluid including the small droplet DS of the second liquid smaller than the opening of the nozzle 21, the energy of the collision of the small droplet DS causes the nozzle 21 Clogging can be eliminated. When the foreign matter that has caused the clogging of the nozzle 21 enters the common liquid chamber 100 inside the nozzle 21, the foreign matter is discharged by the fluid injection maintenance performed by the fluid injection device (fluid injection device 775D). can do. Therefore, since the device for eliminating clogging of the nozzle 21 is also used by the (fluid ejection device 775D), the configuration of the liquid ejecting device 7 can be reduced as compared with the case where a device for eliminating clogging of the nozzle 21 is separately provided. It can be simplified.

The above embodiments may be modified as in the following modification examples. Further, each of 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 unit 1 (1C) having two liquid ejecting heads 3 (3A, 3B) to which ink is supplied from one differential pressure valve 731 through the supply channel 732 is provided. In some cases, maintenance of the liquid ejecting heads 3A, 3B may be performed by the fluid ejecting devices 775, 775B, 775D. In the liquid ejecting unit 1C, fluid injection maintenance for injecting fluid from all the nozzles 21 of one liquid ejecting head 3A and discharging liquid from all the nozzles 21 of the other liquid ejecting head 3B can also be performed.

  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 portion 836 for storing the liquid for injection, a cap 837 capable of forming a closed space in which the nozzle 21 of the liquid ejecting head 3 opens, and a connection for connecting the storage portion 836 and the cap 837. A supply channel 838 and a supply pump 839 for supplying the liquid in the storage section 836 to the cap 837 under pressure are provided. Then, the cap 837 is brought into contact with, for example, the liquid ejecting head 3A 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 of the liquid ejecting head 3A, the supply channel 732, and the other liquid ejecting head 3B And the liquid is discharged together with the foreign matter from the nozzle 21 of the liquid ejecting head 3B.

  As in the second modification shown in FIG. 23, instead of the external mixing type fluid ejection nozzle 778, the second liquid supplied from the liquid flow path 788a is mixed with air supplied from the gas flow path 783a. A so-called internal mixing type fluid jet nozzle 778B having a mixing section KA for generating a mixed fluid inside may be used. In this case, the mixed fluid generated in the mixing section KA is ejected from the ejection port 778j provided at the tip (upper end) of the fluid ejection nozzle 778B.

  -With respect to the fluid ejection in each mode in the second embodiment, the ejection direction, ejection speed, droplet diameter, and ejection pressure can be arbitrarily changed. For example, the fluid ejection of each mode may be performed in the first ejection direction S1 using the same fluid ejection device 775 as in the first embodiment.

  -Before injecting the mixed fluid from the fluid ejection nozzle 778 to the liquid ejection units 1A and 1B including the nozzle 21, the second liquid is ejected to the liquid ejection units 1A and 1B including the nozzle 21. Is also good. In this case, a liquid supply pump 793 may be used to eject the second liquid from the liquid ejection nozzle 780. However, a pump for ejecting the second liquid from the liquid ejection nozzle 780 at an intermediate position of the liquid supply pipe 788 is separately provided. Preferably, it is provided. With this configuration, the second liquid is first jetted to the liquid jetting units 1A and 1B including the nozzle 21, and then the mixed fluid is jetted by mixing air into the second liquid. In addition, it is possible to suppress that only air is injected to the liquid injection units 1A and 1B including the nozzle 21. Therefore, it is possible to suppress the air injected into the liquid ejecting units 1A and 1B including the nozzle 21 from entering the inside 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, the injection of the air is stopped first, and then the injection of the second liquid is stopped. Injection of only air to the liquid ejecting units 1A and 1B including the nozzle 21 can be suppressed.

  The temperature ejection sensor 711 (see FIG. 2) provided on the carriage 723 may be used to detect fluid ejection failure in the fluid ejection devices 775B and 775D. That is, a liquid or a fluid containing liquid is ejected from the fluid ejection nozzle 778 of the fluid ejection device 775 or 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. , The fluid ejection failure in the fluid ejection devices 775B and 775D is detected.

  Specifically, if the liquid is properly ejected from the fluid ejection nozzles 778 and 778B, the liquid contacts the temperature sensor 711 to cool the temperature sensor 711, and the temperature sensor 711 detects a decrease in temperature. By doing so, it is possible to detect that the liquid is properly ejected from the fluid ejection nozzles 778 and 778B. On the other hand, when the temperature of the temperature sensor 711 does not decrease even though the fluid ejecting devices 775 and 775D perform the ejecting operation, defective ejection of the liquid may occur due to clogging of the fluid ejecting nozzles 778 and 778B or running out of the liquid. It can be determined that it has occurred.

  A pressurizing pump for supplying ink in an ink tank (not shown) to the storage unit 730 is provided, and the clogged nozzle 21 during ejection of the mixed fluid from the fluid ejection nozzle 778 to the clogged nozzle 21 is provided. The pressurization of the ink in the communicating pressure generating chamber 12 may be performed by the pressurizing pump with the differential pressure valve 731 being opened.

  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 to regions of the liquid ejecting units 1A and 1B that do not include the nozzle 21. You may do so. Further, before performing the injection of the mixed fluid from the fluid ejection nozzle 778 to the liquid ejection units 1A and 1B including the nozzle 21, the second liquid is ejected at a position where the fluid ejection nozzle 778 does not face the liquid ejection units 1A and 1B. You may make it. Even in this case, it is possible to suppress the injection of only air to the liquid ejecting units 1A and 1B including the nozzle 21.

  -The 2nd liquid which is the 2nd liquid may be constituted only by pure water (pure water which does not contain a preservative). In this way, when the second liquid mixes with the ink in the nozzle 21, the second liquid can be prevented from adversely affecting the ink.

  When ejecting the mixed fluid to the clogged nozzle 21, the actuator 130 corresponding to the clogged nozzle 21 may be driven in the same manner as when ejecting ink during printing or during flushing. Even in this case, it is possible to suppress the mixed fluid from entering the clogged nozzle 21.

  When the mixed fluid is jetted 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. The pressure generating chambers 12 may be pressurized. This can prevent the mixed fluid from entering the nozzles 21 other than the clogged nozzle 21.

-The fluid ejection device 775 may be arranged in the non-printing area RA.
A wiper for wiping the liquid ejection surfaces 20a of the liquid ejection units 1A and 1B may be separately provided between the fluid ejection device 775 and the printing area PA in the non-printing area LA. With this configuration, after the fluid ejecting apparatus 775 ejects the mixed fluid to the liquid ejecting units 1A and 1B, the mixed fluid (the second liquid) is moved before the printing unit 720 is moved to the home position HP side across the printing area PA. The liquid ejecting surface 20a wetted in the step (2) can be wiped by 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.

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

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

  The nozzle row NL (nozzle 21) that ejects ink of a color (kind) that is used extremely infrequently is used without regular maintenance (such as suction cleaning, flushing, and wiping). Clogging may be eliminated by cleaning with the fluid ejection device 775, 775D. By doing so, the amount of ink used for ink (color) that is used very rarely in suction cleaning and flushing is reduced, so that the ink can be saved.

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

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

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

  The ink used in the liquid ejecting apparatus 7 contains a resin in composition, and does not substantially contain glycerin having a boiling point of 290 ° C. at 1 atm. When the ink substantially contains glycerin, the drying property of the ink is significantly reduced. As a result, in various types of media, particularly, non-ink-absorbing or low-absorbing media, not only is the density unevenness of the image conspicuous, but also the ink fixability is not obtained. Further, it is preferable that the ink does not substantially contain an alkyl polyol (excluding the above-mentioned glycerin) having a boiling point of 280 ° C. or higher at 1 atm.

  Here, “substantially not contained” in the present specification means that the substance is not contained in an amount that is sufficient to exhibit the significance of addition. Quantitatively speaking, it is preferable that glycerin is not contained in an amount of not less than 1.0% by mass, more preferably not more than 0.5% by mass, based on the total mass (100% by mass) of the ink. It is still more preferably not contained more than 0.1% by mass, even more preferably not more than 0.05% by mass, particularly preferably not more than 0.01% by mass. Most preferably, glycerin is not contained in an amount of 0.001% by mass or more.

Next, additives (components) contained in or capable of being contained in the ink will be described.
[1. Color material]
The ink may include a coloring material. The coloring material is selected from pigments and dyes.

[1-1. Pigment]
By using a pigment as a coloring material, the light resistance of the ink can be improved. As the pigment, any of an inorganic pigment and an organic pigment can be used. Examples of the inorganic pigment include, but are not particularly limited to, carbon black, iron oxide, titanium oxide, and silica oxide.

  Examples of the organic pigment include, but are not particularly limited to, for example, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, 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 the pigment used for the 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, 60. Among them, C.I. I. Pigment Blue 15: 3 and 15: 4 are preferred.

  Pigments used for 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, C.I. I. Pigment Violet 19 is preferable.

  Examples of the pigment used for the 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. Pigment Yellow 74, 155, and 213 are preferred.

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

[1-2. dye]
A dye can be used as a coloring material. The dye is not particularly limited, and an acidic dye, a direct dye, a reactive dye, and a basic dye can be used. The content of the coloring material is preferably from 0.4 to 12% by mass, more preferably from 2% by mass to 5% by mass, based on 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, and 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 higher, and more preferably 60 ° C. or higher, since the resin 21 is less likely to cause clogging of the nozzle 21 and has an advantageous effect of imparting abrasion resistance to the medium. More preferred.

  Here, the “thermal deformation temperature” in this specification is a temperature value represented by a glass transition temperature (Tg) or a minimum film forming temperature (MFT). That is, “the heat distortion temperature is 40 ° C. or higher” means that either Tg or MFT may be 40 ° C. or higher. In addition, since MFT is easier to grasp the resilience of the resin than Tg, the heat deformation temperature is preferably a temperature value represented by MFT. If the ink has excellent resin re-dispersibility, the ink does not adhere and the nozzle 21 is less likely to be clogged.

  Specific examples of the thermoplastic resin include, but are not particularly limited to, poly (meth) acrylate or a copolymer thereof, polyacrylonitrile or a copolymer thereof, polycyanoacrylate, polyacrylamide, and poly (meth) acrylic acid. (Meth) acrylic polymers, polyethylene, polypropylene, polybutene, polyisobutylene, and polystyrene, and their copolymers, and polyolefin-based polymers such as petroleum resins, cumarone-indene resins, and terpene resins, and polyvinyl acetate Or a copolymer thereof, a polyvinyl acetate-based or vinyl alcohol-based polymer such as polyvinyl alcohol, polyvinyl acetal, and polyvinyl ether; polyvinyl chloride or a copolymer thereof; polyvinylidene chloride; a fluororesin; Polymer, polyvinylcarbazole, polyvinylpyrrolidone or copolymer thereof, nitrogen-containing vinyl polymer such as polyvinylpyridine and polyvinylimidazole, polybutadiene or copolymer thereof, diene system such as polychloroprene and polyisoprene (butyl rubber) Polymers, and other ring-opening polymerization type resins, condensation polymerization type resins, and natural polymer resins.

  The content of the resin is preferably from 1 to 30% by mass, more preferably from 1 to 5% by mass, based on the total mass (100% by mass) of the ink. When the content is within the above range, the glossiness and the abrasion resistance of the formed overcoated image can be further improved. 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 include a resin emulsion. The resin emulsion, when the medium is heated, preferably forms a resin film together with a 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 effects, the ink becomes excellent in 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 that functions as a binder in the ink in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in an 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 , Vinylpyridine, vinylcarbazole, vinylimidazole, and vinylidene chloride homopolymers or copolymers, fluororesins, and natural resins. Among them, any one of a methacrylic resin and a styrene-methacrylic acid copolymer resin is preferable, and any one of an acrylic resin and a styrene-acrylic acid copolymer resin is more preferable, and a styrene-acrylic acid copolymer resin is preferable. Even more preferred. In addition, the above-mentioned copolymer may be in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, 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 based on 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 ejection stability can be further improved.

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

  When the ink contains polyethylene wax, the ink can have excellent abrasion resistance. The average particle size 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 content (in terms of solid content) of the polyethylene wax is, independently of each other, preferably in the range of 0.1 to 3% by mass relative to the total mass (100% by mass) of the ink, and 0.3 to 3%. It is more preferably in the range of mass%, more preferably in the range of 0.3 to 1.5 mass%. When the content is within the above range, the ink can be satisfactorily solidified and fixed even on a non-ink-absorbing or low-absorbing medium, and the storage stability and ejection stability of the ink are more excellent. Things.

[3. Surfactant]
The ink may include a surfactant. Examples of the surfactant include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of uniformly spreading the ink on the medium. Therefore, when printing is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be 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 surfactants. An activator is mentioned, and among them, a silicon-based surfactant is preferable.

  The content of the surfactant is 0.1% by mass or more and 3% by mass or less with respect to the total mass (100% by mass) of the ink because the storage stability and the ejection stability of the ink are further improved. It is preferably within the range.

[4. Organic solvent]
The ink may include a known volatile water-soluble organic solvent. However, as described above, the ink is substantially free of glycerin (a boiling point at 1 atm. Is 290 ° C.), which is a kind of organic solvent, and is an alkyl polyol having a boiling point at a pressure of 1 atm. (Excluding glycerin) is preferably not substantially contained.

[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 nozzle 21 during printing can be effectively suppressed. In addition, since it has a property of dissolving a medium such as vinyl chloride, the adhesion of an image 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 include 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. And typical examples of the sulfoxides include dimethyl sulfoxide and tetramethylene sulfoxide.

  Representative examples of imidazolidinones include 1,3-dimethyl-2-imidazolidinone, representative examples of sulfolane include sulfolane and dimethylsulfolane, and representative examples of urea derivatives include dimethyl urea and 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.

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

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

Next, the components of the surfactant mixed with the second liquid will be described.
Examples of the surfactant include cationic surfactants such as alkylamine salts and quaternary ammonium salts; anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; alkyldimethylamine oxide Surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers; And the like, and among them, an anionic surfactant or a nonionic surfactant is particularly preferable.

  The content of the surfactant is preferably 0.1 to 5.0% by mass based on the total mass of the second liquid. Furthermore, the content of the surfactant is preferably from 0.5 to 1.5% by mass with respect to the total mass of the second liquid from the viewpoint of foaming properties and defoaming properties after foaming. In addition, only one surfactant may be used, or two or more surfactants may be used. 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) 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 preferred.

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

  The surfactant has a function of making the aqueous ink easily spread on the recording medium. The surfactant that can be used in the present invention is not particularly limited, and anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl Nonionic surfactants such as ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; silicone-based surfactants; For example, a fluorine-based surfactant can be used.

  The surfactant has an effect of disaggregating and dispersing the aggregate by the surface active effect between the cleaning liquid (second liquid) and the aggregate. Further, since the cleaning liquid has a function of lowering 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.

  Any surfactant can be suitably used as long as it has a hydrophilic part and a hydrophobic part in the same molecule. Specific examples are preferably those represented by the following formulas (I) to (IV). That is, a polyoxyethylene alkylphenyl ether-based surfactant of the following formula (I), an acetylene glycol-based surfactant of the formula (II), a polyoxyethylene alkyl ether-based surfactant of the following formula (III), and a compound of the formula (IV) )) Polyoxyethylene polyoxypropylene alkyl ether-based surfactants.

（Ｒは分岐していても良い炭素数６〜１４の炭化水素鎖、ｋ：５〜２０）

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

（ｍ、ｎ≦２０，０＜ｍ＋ｎ≦４０）

(M, n ≦ 20, 0 <m + n ≦ 40)

（Ｒは分岐してもよい炭素数６〜１４の炭化水素鎖、ｎは５〜２０）

(R is a hydrocarbon chain having 6 to 14 carbon atoms which may be branched, and n is 5 to 20)

（Ｒは炭素数６〜１４の炭化水素鎖、ｍ、ｎは２０以下の数）
前記式（Ｉ）〜（IV）の化合物以外では、例えばジエチレングリコールモノフェニルエーテル、エチレングリコールモノフェニルエーテル、エチレングリコールモノアリルエーテル、ジエチレングリコールモノフェニルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコールモノブチルエーテル、テトラエチレングリコールクロロフェニルエーテル等の多価アルコールのアルキル及びアリールエーテル類、ポリオキシエチレンポリオキシプロピレンブロック共重合体等のノニオン系界面活性剤、フッ素系界面活性剤、エタノール、２−プロパノール等の低級アルコール類を用いることができるが、特にジエチレングリコールモノブチルエーテルが好ましい。

(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 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 of alkyl and aryl ethers of polyhydric alcohols such as ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine surfactants, and lower alcohols such as ethanol and 2-propanol. However, diethylene glycol monobutyl ether is particularly preferred.

  F: ejection direction, DS: small droplet, S1: first ejection direction, S2: second ejection direction, ST: medium, 1, 1A, 1B, 1C: liquid ejection unit, 7: liquid ejection 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 (9)

A liquid ejecting unit having a nozzle capable of ejecting the first liquid to the medium,
A fluid ejection device having a fluid ejection nozzle provided with an ejection port capable of ejecting a fluid containing a second liquid to a liquid ejection surface where the nozzle opens,
With
The fluid ejection device,
The fluid ejecting nozzle has a guide unit for guiding the liquid ejecting unit so as to be able to reciprocate along the liquid ejecting surface of the liquid ejecting unit,
Examples maintenance operation to perform maintenance of the liquid ejecting portion, to the liquid ejection surface of the nozzle of the liquid ejecting portion are open, perform fluid injection for injecting a fluid containing a second liquid,
The distance between the ejection port and the liquid ejection surface in the fluid ejection is the distance between the liquid ejection surface and the medium when the liquid ejection unit ejects the first liquid to the medium in the direction of gravity. A liquid ejecting apparatus characterized by being longer.   The fluid ejection nozzle may include a mixing unit that mixes the second liquid supplied through a liquid flow path and a gas supplied through a gas flow path to generate a mixed fluid therein. The liquid ejecting apparatus according to claim 1, wherein:   The liquid flow path is connected to a storage unit that stores the second liquid,
  In the position of the fluid ejection, a position where the gas flows into the mixing unit is located above a position where the second liquid flows into the mixing unit, and is located above a liquid level of the liquid in the storage unit. The liquid ejecting apparatus according to claim 2, wherein: Said fluid containing a second liquid, according to any one of claims 1 to 3, characterized in that ejected from the fluid ejecting nozzle in the injection direction intersecting obliquely to the liquid ejecting surface Liquid ejector.   The liquid ejecting apparatus according to claim 4, wherein the ejection direction in which the fluid including the second liquid is ejected is along a direction in which the fluid ejecting nozzle of the fluid ejecting apparatus reciprocates.   The method according to any one of claims 1 to 5, wherein, as the maintenance operation, after the fluid including the second liquid is ejected to the liquid ejection surface, the first liquid is discharged from the nozzle. Item 6. The liquid ejecting apparatus according to item 1. A wiping member capable of wiping the liquid ejecting unit,
7. The liquid ejecting apparatus according to claim 1, wherein, as the maintenance operation, after the fluid including the second liquid is ejected to the liquid ejecting surface, the liquid ejecting surface is wiped by the wiping member. The liquid ejecting apparatus according to claim 1. The liquid ejecting unit has a pressure generation chamber communicating with the nozzle, and an actuator capable of pressurizing the pressure generation chamber,
In a state where the first liquid in the pressure generation chamber is pressurized by the driving of the actuator in the liquid ejecting unit, the fluid ejecting apparatus ejects the fluid including the second liquid to the liquid ejecting surface. The liquid ejecting apparatus according to any one of claims 1 to 7, wherein: The fluid ejecting apparatus can selectively eject three types of gas, the second liquid, and a mixed fluid of the gas and the second liquid from the ejection port,
When the direction in which the fluid ejection device injects the gas from the ejection port is a gas ejection direction,
9. The liquid ejecting apparatus according to claim 1, wherein an angle θ of the gas ejecting direction with respect to the liquid ejecting surface satisfies 0 ° ≦ θ <90 °. 10.

Images