JP5713626B2 - Droplet discharge head and liquid discharge apparatus - Google Patents

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus including the liquid discharge head.

  The so-called continuous type droplet discharge device applies a constant pressure to the liquid with a pump, pushes it out of the nozzle, and further vibrates it with vibration means, so that the state of the liquid discharged from the nozzle regularly drops into droplets. Form. In this method, since the liquid droplets are continuously discharged from the nozzle, it is necessary to select the liquid droplets used for printing and the liquid droplets not used according to the print data. In the so-called charge deflection method, the droplets are selectively charged, deflected by an electric field, and selected so as to fly on a different trajectory from the uncharged droplets. The sorted non-printed droplets are captured and collected by a gutter. In order to realize these functions, a charging electrode, a deflection electrode, and a gutter are provided along the droplet flight trajectory from the nozzle.

  Patent Document 1 discloses a method of sorting droplets without charging the droplets. Specifically, large droplets and small droplets are separated by a nozzle and passed through a liquid curtain made of mist-like droplets formed in the droplet flight path to capture small droplets. Discloses a configuration in which only the recording medium is landed on a recording medium. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for causing another droplet to collide with a flying droplet, although it is not a continuous type liquid ejection device. Specifically, the droplets from the first discharge port collide with the droplets (main droplet) from the first discharge port and deflect the flight direction, thereby causing the satellite droplets (minimum) from the first discharge port. A configuration is disclosed in which only the droplets) are landed on a recording medium so as to reduce the size of the recording dots.

JP 2003-334957 A JP 2008-143188 A

  By the way, if the recording droplets are charged, the flying trajectory may be displaced due to electrostatic interaction with the charged droplets before and after and the charged mist adhering to the wall surface, and the landing accuracy may deteriorate. There is. Even when the recording droplet is not charged, the recording droplet may be charged by electrostatic induction due to the influence of the preceding charged droplet.

  In the method shown in Patent Document 1, since the recording droplet also passes through the liquid curtain, the landing position may be shifted due to the influence of the liquid curtain. In the method disclosed in Patent Document 2, another droplet is caused to fly and land on a gutter to capture a non-recording droplet. However, a splash mist is generated at the time of landing and the flight path may be contaminated. There is sex.

  An object of the present invention is to provide a liquid discharge head capable of suppressing the occurrence of mist in the droplet flight path while improving the landing accuracy of the used droplet (recording droplet), and a liquid discharge apparatus including the liquid discharge head Is to provide.

The liquid ejection head of the present invention collects unused liquid droplets among the first nozzle that continuously ejects liquid droplets and the liquid droplets continuously ejected from the first nozzle. A second nozzle capable of projecting the liquid level so that the liquid droplets ejected from the first nozzle fly, and projecting the liquid level from the second nozzle; A liquid discharge head that collects the unused liquid droplets by colliding and combining the unused liquid droplets discharged from the first nozzle with the protruding liquid surface, and retreating the protruding liquid surface, The second nozzle is located between the center line region of the second nozzle and the inner peripheral wall surface of the second nozzle in the flow path in the direction in which the liquid level protrudes from the second nozzle. structures provided for restricting the flow of liquid in regions Ri, the structure, as compared with the case where the structure is not present, to reduce the flow velocity near the inner circumferential wall acts to increase the flow velocity in the region of the center line, characterized in that.

  According to the present invention, since it is possible to selectively collect unused droplets (non-recording droplets) without affecting the used droplets (recording droplets), the landing accuracy of the used droplets (recording droplets) is improved. It becomes possible to raise. In addition, according to the present invention, by providing a structure near the opening of the second nozzle and restricting the flow of the liquid, the amount of displacement of the liquid surface protruding from the second nozzle can be increased, and the high frequency Even during driving, the used droplets and the unused droplets can be reliably selected.

It is a system outline figure of the liquid discharge device of the present invention. It is sectional drawing of 1st Embodiment of the liquid discharge apparatus of this invention. 1 is an exploded explanatory diagram of a liquid ejection apparatus according to a first embodiment of the present invention. It is a figure of the collection | recovery nozzle of the liquid discharge apparatus of the 1st Embodiment of this invention. It is sectional drawing explaining operation | movement of the liquid discharge apparatus of the 1st Embodiment of this invention. It is a figure showing the simulation result of operation of the liquid discharge device of a 1st embodiment of the present invention. It is a simulation result at the time of using a straight nozzle. It is a simulation result at the time of use of the collection nozzle of the 1st embodiment of the present invention. It is a figure showing the modification of the collection | recovery nozzle which concerns on the 1st Embodiment of this invention. It is sectional drawing of the liquid discharge apparatus which concerns on the 2nd Embodiment of this invention. FIG. 6 is an exploded explanatory diagram of a liquid ejection apparatus according to a second embodiment of the present invention. It is a figure of the collection | recovery nozzle of the 2nd Embodiment of this invention. It is a figure showing the other form of the collection | recovery nozzle which concerns on the 2nd Embodiment of this invention.

[First Embodiment]
A first embodiment of the present invention will be described. The liquid discharge head of the present invention is applicable not only to printing ink using a color material but also to all liquids. In addition, although the droplet discharge head of the present invention is described as an example in which droplets are landed on a recording medium and used for recording, the use is not limited to printing, but a liquid made of a conductive material or a polymer is used. The present invention can be widely applied to a manufacturing apparatus and an analysis apparatus using a liquid containing protein.

  FIG. 1 is a system schematic diagram of a liquid ejection apparatus equipped with a liquid ejection head according to the first embodiment. The liquid ejection apparatus according to this embodiment includes an ink tank 001, a pressure pump 002, a vibration mechanism 003, a head 004, a controller 005, a recovery pump 006, and an ink adjustment unit 007. A thick line indicates an ink transport path, and a thin line indicates an electric signal transmission path.

  FIG. 2 is a cross-sectional view of the head 004 viewed from the Z direction. FIG. 3A is an exploded explanatory view of plates to be stacked as viewed from the Z direction. FIG. 3B is an exploded explanatory view of the recovery nozzle portion viewed from the X direction. In this embodiment, a configuration of a two-dimensional multi-nozzle head in which nozzle rows are formed in the Y direction and nozzle rows are arranged in the X direction is shown.

  The head 004 includes a discharge nozzle 101 (first nozzle), a recovery nozzle 102 (second nozzle), and a liquid level driving mechanism 103 (driving mechanism). As shown in FIG. 2, the liquid level driving mechanism 103 is provided adjacent to the recovery flow path 116 communicating with the recovery nozzle 102, and causes the liquid level of the liquid in the recovery nozzle 102 to protrude from the front end opening of the recovery nozzle 102. It is possible. The liquid surface protruding from the recovery nozzle 102 is arranged so as to be positioned on the flight trajectory 117 of the droplets continuously discharged from the discharge nozzle 101.

  As shown in FIGS. 2 and 3, the head 004 is configured by laminating plate-like members. The supply flow path plate 121 that forms the supply flow path 115 of the discharge ink, the individual flow path plate 122 that forms the taper flow path corresponding to the individual nozzle, and the discharge nozzle plate 123 that forms the discharge nozzle 101 are droplet flying. Laminate in the same Z direction as the track. The recovery flow path part 210 is formed by being laminated in the X direction perpendicular to the droplet flight trajectory, and is bonded to the discharge nozzle plate 123.

  As shown in FIG. 3B, the flow rate limiting structure 301 is provided in the flow path in the recovery nozzle 102 by stacking the flow speed limiting structure plate 202 between the recovery nozzle plate 201 and the recovery flow path plate 203. . The recovery channel has a pressure chamber composed of the diaphragm 114 and the piezoelectric element 112, and drives the liquid level of the recovery nozzle. Here, the configuration of the recovery nozzle 102 provided with the double cylindrical flow rate limiting structure 301 shown in FIG. 4 is shown. Although the flow rate limiting structure 301 is formed of the flow rate limiting structure plate 202 and is configured as a separate member from the recovery nozzle plate 201 and the recovery flow path plate 203, the same member may be used.

  Silicon, stainless steel, resin material, etc. can be used for these laminated members. By producing these plate-like members by patterning by exposure, etching, or pressing, even when the number of nozzles is increased, batch processing is possible, and the number of parts is not increased, and a head can be manufactured at low cost. In this embodiment, a thin film piezoelectric element is used as the liquid level driving mechanism 103. Specifically, the upper electrode 111, the piezoelectric element 112, and the lower electrode 113 are formed on the diaphragm 114. Sputtering or the like can be used for film formation, and dry etching can be used for patterning.

  In FIG. 3, the nozzle interval in the Y direction is, for example, 500 μm, and the nozzle interval in the X direction is 3 mm. A liquid having a viscosity of 1 to 40 cP and a surface tension of 30 mN / m can be used. For example, in the case of 40 cP ink, if the diameter of the discharge nozzle 101 is 7.4 μm, the pressure of the ink tank 002 is 0.8 MPa, and the vibration frequency of the vibration mechanism 003 is 50 kHz, the droplet size is 4 pL (diameter approximately 20 μm), The discharge speed is about 10 m / s.

  4A and 4B are diagrams showing a flow path structure in the recovery nozzle 102 of the present embodiment, where FIG. 4A is a perspective view, FIG. 4B is a cross-sectional view, and FIG. 4C is a side view as viewed from the recovery nozzle 102 side. . In FIG. 4, the liquid level protrudes in the minus X direction. As shown in FIG. 4, a flow rate limiting structure 301 is provided at a position separated from the opening surface of the recovery nozzle 102 by a distance equal to or larger than the radius of the recovery nozzle 102.

  The flow rate limiting structure 301 is provided, for example, at a position retracted from the opening of the recovery nozzle 102 of about φ80 μm to the flow path side by about 50 μm, and supports the cylindrical portion 301a having a length of about 50 μm and the cylindrical portion 301a. For this reason, a support portion 301b that protrudes outward is provided. The cylindrical portion (tubular portion) 301 a is provided concentrically with the recovery nozzle 102. The arrangement position of the cylindrical portion 301a is preferably at least a distance from the opening of the second nozzle 102 that is larger than 40 μm, which is the radius of the inscribed circle of the opening.

  Next, the operation of the liquid ejection apparatus according to the present embodiment will be described with reference to the head sectional view shown in FIG.

  The diameter of the collection nozzle 102 is, for example, about 80 μm, and is provided at a point about 1 mm away from the discharge nozzle 101 in the droplet flight direction.

  The ink IK stored in the ink tank 001 is pressurized by the pressure pump 002 and supplied to the head 004. The ink IK supplied to the head 004 is vibrated by the vibration mechanism 003 and discharged from the discharge nozzle 101 as a liquid column. When the ink ejected from the nozzle 101 reaches a position separated by about 500 to 800 μm, it splits from the liquid column into droplets and flies along a droplet flight trajectory 117 indicated by a one-dot chain line. The discharged liquid droplets are decelerated to about 8 m / s when passing through the vicinity of the recovery nozzle 102 due to air resistance. Further, the droplet flight trajectory 117 is 30 μm away from the recovery nozzle 102. On the other hand, the recovery nozzle 102 balances the negative pressure (about −1.4 kPa with respect to the atmospheric pressure) by the recovery pump 006 and the meniscus force, so that the liquid level becomes the recovery nozzle 102 as shown in FIG. Is held near the opening.

  When a droplet (unused droplet) 118 that is not used for recording passes in the vicinity of the recovery nozzle 102, the liquid level driving mechanism 103 causes the recovery nozzle 103 to receive a signal from the controller 005 as shown in FIG. The liquid level is projected from the opening 102 so as to be positioned on the droplet flight trajectory 117. Then, the unused liquid droplet 118 flying is collided with the protruding liquid surface PR projected from the opening of the recovery nozzle 102, thereby capturing the unused liquid droplet 118.

  Thereafter, the unused droplet 118 merges with the protruding liquid surface PR, and the protruding liquid surface PR returns to the original static position due to surface tension. By maintaining the pressure constant by the recovery pump 006, the liquid level of the recovery nozzle 102 is maintained at a constant position even after capture. In particular, the amount of displacement of the liquid level driving mechanism 103 is controlled so that the protruding liquid level PR does not drop. The captured droplet is gradually sent to the ink adjusting unit 007, and after dust removal and viscosity adjustment, the pressurized liquid is pressurized again by the pressure pump 002 and circulated to the head 004 for reuse. . On the other hand, when a droplet used for recording (used droplet) passes in the vicinity of the recovery nozzle 102, the liquid level of the recovery nozzle 102 does not protrude (advance) and the liquid level of the recovery nozzle 102 flies. Do not cross the track 117. As a result, the used droplets land on the recording medium 008 as they are.

  As described above, by controlling the liquid level driving mechanism 103 in accordance with the recording data, the liquid droplets not used for recording are collected by the protruded liquid surface, and only the liquid droplets used for recording are transferred to the recording medium 008. Can be landed. In addition, by holding the recording medium in a transport unit (not shown), a desired image can be recorded by transporting the recording medium in accordance with the droplet discharge timing.

  When performing high-speed recording, the subsequent droplets may pass before the liquid level of the recovery nozzle 102 completely returns to the position at the time of stabilization. Even in such a case, if the difference between the position of the liquid surface of the recovery nozzle 102 at the time of forward movement and backward movement is sufficient and the unused liquid droplet can be captured and the used liquid droplet can be passed, the liquid ejection according to the present embodiment is performed. The device functions normally. In the present embodiment, a structure 301 that restricts the flow in the region between the nozzle central region and the nozzle inner peripheral surface is arranged inside the recovery nozzle 102, and thereby the liquid level of the recovery nozzle 102 is advanced. And a sufficient difference in position when retreating.

  In the present embodiment, the case where the negative pressure is maintained by the recovery pump 006, the liquid level is moved backward by the recovery nozzle 102, and the liquid level is advanced by the liquid level driving mechanism 103 when the unused droplets pass is described. Conversely, the positive pressure may be maintained by the recovery pump 006, the liquid level may be advanced by the recovery nozzle 102, and the liquid level may be retracted by the liquid level driving mechanism 103 when the used droplets pass. In this case, it is preferable that the outer surface of the recovery nozzle 102 is subjected to a water repellent treatment so that the liquid surface does not spread by wetting the outer surface in a state where positive pressure is applied. This method is effective in reducing power consumption and heat generation in a state where all of the ejected ink is collected without performing recording, such as during standby.

In FIG. 2, the liquid level driving mechanism 103 uses a piezoelectric element on a thin film, but other types of driving means may be used. For example, if the piezoelectric element, it may be used by laminating bulk piezoelectric elements may be utilized deformation of d ₁₅ direction by using the piezoelectric element on the side walls (shear mode). Alternatively, the driving means may be a heater, and the liquid level may be driven by foaming due to film boiling. When a heater is used, a large displacement can be easily obtained and the size can be reduced as compared with the case where a piezoelectric material is used, so that the nozzle density can be increased. On the other hand, when a piezoelectric element is used, the liquid level can be accurately controlled by optimizing the drive waveform.

  Next, the result of analyzing the operation of the liquid level protruding from the recovery nozzle 102 of the present embodiment using general-purpose fluid analysis software will be described.

  The ink viscosity was 40 cP, the surface tension was 30 mN / m, and a movement corresponding to the liquid level driving mechanism 103 was given a displacement of a sine waveform of ± 20 nm and 50 kHz to the contact.

  FIG. 6 shows the simulation result. 6 shows the movement of the liquid level of the recovery nozzle 102, and (a1) and (a2) in FIG. 6 are the analysis results of a straight nozzle in which the flow rate limiting structure 301 does not exist, and (b1) and (b2) in FIG. Is the analysis result of the nozzle provided with the flow rate limiting structure 301. The straight nozzle has a difference of 4.9 μm between the forward and backward movement of the liquid level, whereas the difference between the nozzle with the double-cylinder flow restricting structure 301 and 18.7 μm is large. I understand that there is.

The behavior of these liquid levels will be described in detail below.
FIG. 7 shows a flow velocity vector diagram and a pressure contour diagram of the simulation result of the straight nozzle. In the figure, the right direction is the forward direction of the liquid level, and the pressure contour diagram indicates that the lighter the color, the higher the pressure.

  First, at the time of maximum advance ((V1) in FIG. 7), the liquid level near the inner peripheral wall is greatly depressed (see the broken line ellipse A in FIG. 7), and the flow velocity in the flow path causes the liquid level to recede. It is a direction (broken line ellipse B in FIG. 7). When the liquid surface is retracted ((V2) in FIG. 7), the flow velocity in the vicinity of the liquid surface at the center is very small (see the broken line ellipse C in FIG. 7). Further, it can be seen that the flow velocity in the flow channel has already been reversed in the forward direction, and the flow velocity in the vicinity of the inner peripheral wall surface is larger than that in the central portion (see broken line ellipse D in FIG. 7).

  At the time of the minimum retreat of the central portion of the protruding liquid surface ((V3) in FIG. 7), the liquid surface near the inner peripheral wall that has been depressed returns to the vicinity of the opening of the recovery nozzle 102 (broken line in FIG. 7). (See ellipse E). When the central portion of the protruding liquid surface starts to move forward ((V4) in FIG. 7), the flow velocity in the flow path is in the backward direction, and the flow velocity near the inner peripheral wall surface is faster than the central portion. (Refer to the broken line ellipse F in FIG. 7). Also at this time, the flow velocity in the vicinity of the liquid surface at the center portion protruding is very small (see the broken line ellipse G in FIG. 7).

  From the above, the movement of the liquid level in the vicinity of the inner peripheral wall surface of the recovery nozzle 102 follows the change in the flow velocity in the flow path, while the liquid level in the center moves with a delay. It can be seen that the phase of is shifted. In addition, the amount of displacement of the liquid surface near the inner peripheral wall surface is large while the amount of displacement of the liquid surface at the center is small, and most of the energy of the liquid surface driving mechanism 103 is consumed near the inner peripheral wall surface of the recovery nozzle 102. Will be.

  The reason why the displacement amount of the liquid surface near the inner peripheral wall surface of the recovery nozzle 102 is large will be considered from the pressure gradient. Looking at the pressure contour diagram (C2 in FIG. 7) at the time of liquid level receding, the pressure gradient near the inner wall surface is large (see the dashed ellipse H in FIG. 7), and the pressure gradient near the center is small. (Refer to the broken line ellipse I in FIG. 7). From this, it is understood that the energy of the liquid level driving mechanism 103 is consumed as energy for moving the liquid level near the inner peripheral wall surface before moving the liquid level at the center. The pressure contour (C4 in FIG. 7) at the time of liquid level rise is the same, the pressure gradient in the vicinity of the inner peripheral wall surface is large (see the broken line ellipse J in FIG. 7), and the pressure gradient in the vicinity of the center is small (FIG. 7). It can be seen that the broken-line ellipse K in FIG.

  FIG. 8 shows a flow velocity vector diagram and a pressure contour diagram of a simulation result of a double cylindrical recovery nozzle provided with the flow velocity limiting structure 301 of the present embodiment.

  First, at the time of maximum advance ((V1 in FIG. 8)), the flow velocity in the center of the flow path is high due to the effect of the flow velocity limiting structure 301, and the flow velocity near the inner peripheral wall surface is suppressed (broken line in FIG. 8). (See ellipse A). At the time of retreat of the liquid level ((V2 in FIG. 8)), the flow velocity in the retreat direction becomes high at the center of the protruding liquid surface (see the broken line ellipse B in FIG. 8).

  At the time of the minimum retreat of the central portion of the protruding liquid surface ((V3) in FIG. 8), the flow velocity at the central portion of the flow path is high (see the broken line ellipse C in FIG. 8). When the central portion of the protruding liquid surface begins to advance ((V4) in FIG. 8), the flow velocity in the forward direction increases at the central portion of the liquid surface (broken line ellipse D in FIG. 8).

  From the above, both the movement of the liquid surface near the inner peripheral wall surface and the movement of the liquid surface in the central portion follow the movement of the flow velocity in the flow path of the recovery nozzle 102, and compared with the straight nozzle described above. Then, it turns out that the phase difference between both becomes small. Further, the amount of displacement of the liquid surface near the inner peripheral wall surface of the recovery nozzle 102 is suppressed, and accordingly, the amount of displacement of the liquid surface at the center is increased. This is because the flow velocity distribution in the flow path of the recovery nozzle 102 has a large peak at the center due to the action and effect of the flow velocity limiting structure 301.

  Further, when the pressure contour at the time of retreat of the liquid surface ((C2) in FIG. 8) is seen, the pressure distribution at the center portion is raised in the forward direction (see the broken line ellipse E in FIG. 8). The pressure gradient near the center of the surface is larger than in the case of the straight nozzle. Similarly, the pressure contour at the time of advancement of the liquid level ((C4) in FIG. 8) has a shape in which the pressure distribution at the center is raised in the advance direction (see the broken line ellipse F in FIG. 8).

  As described above, the flow rate limiting structure 301 arranged in the recovery nozzle 102 relatively reduces the flow velocity and pressure gradient in the vicinity of the inner peripheral wall surface as compared with the case where the structure 301 does not exist, It acts to relatively increase the flow velocity and pressure gradient. Further, since the flow rate limiting structure 301 suppresses the operation phase difference with the liquid level driving mechanism 103 to be small, the energy loss is reduced and the positional difference (displacement amount) between the forward and backward movement of the protruding liquid surface is increased. be able to. That is, paying attention to the fact that the liquid flow velocity and pressure distribution in the direction from the central region toward the inner peripheral wall region in the vicinity of the opening of the recovery nozzle 102 are related to the displacement amount of the protruding liquid surface, the liquid flow velocity and pressure distribution are structured. By controlling with the body 301, the amount of displacement of the protruding liquid surface can be increased.

  Thus, by disposing the flow rate limiting structure 301 in the flow path in the recovery nozzle 102 so as to limit the flow between the center region and the inner peripheral wall surface region, the displacement operation of the liquid level of 50 kHz can be performed. The droplets were selected and the desired printing was achieved.

  In addition, the configuration of the double cylinder that divides the flow path in the recovery nozzle 102 into the central region and the inner peripheral wall surface region has been described so far, as shown in FIGS. 9A and 9B. The same effect can be obtained by arranging the structures 302 and 303 serving as resistors in the wall surface region. The structure 302 is an annular member that fits to the inner peripheral wall surface of the recovery nozzle 102. The structural body 303 is a plurality of projecting members arranged along the circumferential direction of the inner peripheral wall surface of the recovery nozzle 102.

[Second Embodiment]
A second embodiment of the present invention will be described. FIG. 10 is a cross-sectional view of the configuration of the liquid discharge head in this embodiment, and FIG. The flow rate limiting structure 304 of the flow path in the recovery nozzle 102 of the present embodiment has a structure as shown in FIG. By making the structure of a square nozzle and a flat plate, the stacking directions are all the same Z direction, so that the manufacture becomes easy.

  As can be seen in FIG. 10, all the plates are stacked in the same Z direction as the droplet flight trajectory 117. As shown in the exploded explanatory view of FIG. 11, the flow rate limiting structure 304 is formed by alternately stacking the recovery flow path plates (404, 406, 408) and the flow rate limiting structure plates (405, 407). Can do.

  The flow rate limiting structure 304 is formed of a flow rate limiting structure plate (405, 407) and is configured as a separate member from the recovery flow path plate, but may be configured as the same member.

  In FIG. 12, the length of the rectangular piece of the recovery nozzle 102 is 80 μm, and the flow rate limiting structure 304 is disposed at a position drawn from the opening surface of the recovery nozzle 102 to the 50 μm flow path side.

  Also in the present embodiment, the liquid level displacement operation can be realized, and a desired printing can be performed by selecting a droplet.

  As described above, the effect similar to that of the first embodiment can be obtained by including the structure 304 that restricts the flow of the inner peripheral wall surface, although only on the two sides of the square nozzle.

  In addition, the same effect can be obtained by the same manufacturing method even if the double rectangular tube type 305 as shown in FIG. 13 is used.

  In the above-described embodiment, various structural examples have been described as the structure. However, the structure is not limited thereto, and the structure capable of controlling the flow rate and pressure distribution of the liquid so that the displacement amount of the protruding liquid surface can be increased. Any body can be used.

  The liquid discharge head of the present invention has little impact on the flying of the droplets used during the selection and recovery of the droplets, so that high landing accuracy can be obtained and used for the production of a high-definition liquid discharge head can do.

001 Ink tank 002 Pressurizing pump 003 Excitation mechanism 004 Head 005 Controller 006 Collection pump 007 Ink adjustment unit 008 Recording medium 101 Discharge nozzle 102 Recovery nozzle 103 Liquid level driving mechanism 301, 302, 303, 304, 305 Flow rate limiting structure

Claims (9)

A first nozzle that continuously discharges droplets and an unused droplet out of the droplets continuously discharged from the first nozzle are discharged from the first nozzle. A second nozzle capable of projecting the liquid level so as to be positioned in a trajectory where the liquid droplets fly, the liquid level is projected from the second nozzle, and the first liquid is projected onto the projected liquid level. A liquid discharge head that collects the unused droplets by colliding and combining the unused droplets ejected from the nozzle, and retreating the protruding liquid surface,
The second nozzle includes, in its flow path, a region of the center line of the second nozzle in a direction in which the liquid level protrudes from the second nozzle, and an inner peripheral wall surface of the second nozzle. A structure for restricting the flow of the liquid in the region between is provided , and the structure reduces the flow velocity in the vicinity of the inner peripheral wall surface compared to the case where the structure does not exist, and the center line A liquid discharge head , which acts to increase the flow velocity in the area of the liquid.   2. The liquid ejection head according to claim 1, wherein the structure includes a cylindrical portion disposed concentrically with the second nozzle and a support portion that supports the cylindrical portion.   2. The liquid discharge head according to claim 1, wherein the structure is an annular member that is fitted to an inner peripheral wall surface of the second nozzle.   The liquid ejection head according to claim 1, wherein the structure is a plurality of projecting members arranged along a circumferential direction of an inner peripheral wall surface of the second nozzle.   5. The liquid ejection head according to claim 1, wherein the structure is disposed apart from an opening of the second nozzle. 6.   6. The liquid ejection head according to claim 5, wherein the structure is arranged at a distance greater than at least a radius of an inscribed circle of the opening from the opening of the second nozzle.   The liquid discharge head according to claim 1, further comprising a drive mechanism that displaces the liquid level.   The liquid ejection head according to claim 7, wherein the drive mechanism is provided adjacent to a flow path communicating with the second nozzle. A first nozzle that continuously discharges droplets and an unused droplet out of the droplets continuously discharged from the first nozzle are discharged from the first nozzle. And a second nozzle capable of projecting the liquid level so as to be positioned in a trajectory on which the liquid droplets fly, the liquid level is projected from the second nozzle, and the first liquid is projected onto the projected liquid level. A liquid discharge head including a recovery unit that collects the unused droplets by colliding and combining the unused droplets discharged from the nozzles of the nozzles, and retreating the protruding liquid surface;
Transport means for transporting a recording medium to the liquid discharge head in order to perform recording by using used liquid droplets among liquid droplets continuously discharged from the first nozzle, The second nozzle includes, in its flow path, a region of the center line of the second nozzle in a direction in which the liquid level protrudes from the second nozzle, and an inner peripheral wall surface of the second nozzle. A structure for restricting the flow of the liquid in the region between is provided , and the structure reduces the flow velocity in the vicinity of the inner peripheral wall surface compared to the case where the structure does not exist, and the center line A liquid ejecting apparatus, wherein the liquid ejecting apparatus acts to increase the flow velocity in the region .