JP2007062022A - System and method for evaluating flight of liquid drop - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize ejection and flight of a liquid drop conveniently when an ink jet recording head of focused ultrasonic system is evaluated in the design stage. <P>SOLUTION: The liquid drop flight evaluation system principally comprises a first position adjustment mechanism 1, a second position adjustment mechanism 2, a rotary drum 3, an imaging device 4, a focused ultrasonic wave generation structure 5, and an ink holding chamber 6. Positional relation between the level of ink liquid 12 and the focused ultrasonic wave generation structure 5 is adjusted by means of the adjusting body 1a, first adjusting arm 1b and second adjusting arm 1c and a third adjusting arm 1d of the first position adjustment mechanism 1. Flight of a liquid drop ejected from the liquid surface toward a recording medium, and an image point formed by impact of the liquid drop are measured by the rotary drum 3. The imaging device 4 measures flight state of the liquid drop. Liquid level in an ink holding chamber 6 is arranged directly under the rotary drum 3 by the second position adjustment mechanism 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet flight evaluation system and a droplet flight of an ink jet recording head, in which, for example, a recording liquid such as liquid ink is reduced into droplets by the pressure of focused ultrasonic waves and the droplets are ejected onto a recording medium to form an image. It relates to the evaluation method.

  Inkjet recording devices that apply energy (also referred to as pressure energy) to ink liquid to make ink droplets small and fly the image onto a recording medium to form an image have been put to practical use as inkjet printers and are widely used. Has been. Many ink jet recording apparatus systems have been devised. Among them, a method of flying droplets with pressure energy generated by the heat of a heating element, a method of flying droplets with pressure energy of ultrasonic waves using a piezoelectric element, and the like are typical.

  In the method using the piezoelectric element, the ultrasonic wave generated by the element is focused near the ink surface by an acoustic lens, and a small droplet is ejected from the ink surface using the pressure of the focused ultrasonic wave. There is a method (hereinafter referred to as focused ultrasound method). Ink jet recording heads other than the normal focused ultrasonic method require thin nozzles for ejecting ink droplets, and ink droplets in the nozzles tend to concentrate due to evaporation of the solvent, etc., leading to ink clogging. On the other hand, a focused ultrasonic type inkjet recording head is nozzle-less and has a structure that is extremely effective against ink clogging (see, for example, Patent Document 1).

  The focused ultrasonic type ink jet recording head will be described with reference to FIG. FIG. 5 is a schematic longitudinal sectional view of the ink jet recording head. As shown in FIG. 5, the focused ultrasonic type inkjet recording head has a structure in which an acoustic lens 11 that focuses ultrasonic waves generated from the piezoelectric element 10 is coupled to the piezoelectric element 10. The piezoelectric element 10 and the acoustic lens 11 focus the focused ultrasonic wave 14 on the liquid level 13 region of the ink liquid 12 and discharge the droplets of the ink liquid 12 from the liquid level 13.

More specifically, in the ink jet recording head shown in FIG. 5A, the piezoelectric element 10 is composed of a plate-like piezoelectric body 10a and opposing upper and lower electrodes 10b and 10c. The piezoelectric body 10a is, for example, a lead titanate ceramic flat plate. Alternatively, it is made of a piezoelectric polymer material such as a ceramic piezoelectric material such as ZnO or LiNbO ₃ or a copolymer of vinylidene fluoride and ethylene trifluoride. The electrodes 10b and 10c are made of, for example, a Ti / Au laminated electrode. In addition, it consists of electrode materials such as Ni, Al and Cu. A drive circuit 15 is connected to the electrodes 10b and 10c. Here, the piezoelectric body 10a has a thickness matched to the resonance frequency of vibration, and the electrodes 10b and 10c are thin films having a thickness of less than 1 μm, for example, formed by sputtering or vapor deposition.

  The acoustic lens 11 is made of, for example, a glass plate having a thickness of about 1 mm, or a mixture of alumina and tungsten powder using a polymer material such as epoxy resin or polyimide as a base material, and has a concave lens structure. It has become.

  The ink liquid 12 is made of, for example, metal or ceramic and is supplied to an ink holding chamber having an upper lid 16 having a thickness of about 0.1 mm. Here, an opening 17 is formed in a part of the upper lid 16, and the liquid level 13 of the ink liquid 12 is exposed in the opening 17.

  In the case of the ink jet recording head shown in FIG. 5B, unlike the case of FIG. 5A, the acoustic lens 11 has grooves of a predetermined pitch formed on the glass plate or polymer material based on the Fresnel zone theory. Made of Fresnel lens. The acoustic lens 11 made of a Fresnel lens is integrally connected to the piezoelectric element 10. Other structures are almost the same as those in FIG.

In the ink jet recording head, the piezoelectric element 10 vibrates when an intermittent high frequency voltage (burst wave) is applied by the driving circuit 15. By this vibration, an ultrasonic standing wave is generated between the acoustic lens 11 and the ink liquid 12 liquid surface. This standing wave is a focused ultrasonic wave 14 focused near the liquid surface 13 of the ink liquid 12. Then, for example, the converging point of the focused ultrasonic wave 14 on the liquid surface 13 of the ink liquid 12 in the opening 13 provided in the upper lid 16 of the ink liquid 12 rises in a conical shape, a meniscus is formed, and the vertex is separated and discharged. Small droplets of ink fly. The droplets of the ink liquid that have been made small droplets fly on the recording medium and form image dots.
JP-A-10-250110

  In the manufacturing design of the above-described focused ultrasonic type ink jet recording head, the resonance frequency of the focused ultrasonic wave can be determined with high accuracy by designing the piezoelectric material of the piezoelectric element 10 and the thickness thereof as described above. The focal length of the focused ultrasonic wave is determined with high accuracy by designing the material and shape of the acoustic lens 11. Thus, the characteristics of the focused ultrasound are determined with high accuracy by the design of the combined piezoelectric element and acoustic lens (hereinafter referred to as a focused ultrasound generating structure). However, until now, in the design stage evaluation of the ink jet recording head as shown in FIG. 5, it has been difficult to easily optimize the ejection of droplets and the flying of the droplets from the recording head. Further, the accuracy of the evaluation data of the recording head structure is not improved, and there is a problem that the head structure cannot be sufficiently optimized in the manufacturing design of the recording head.

  As described above, in the focused ultrasonic type ink jet recording head, the focused ultrasonic wave generation structure focuses the focused ultrasonic wave on the liquid surface region of the ink liquid. And this focused ultrasonic wave becomes a structure which discharges the droplet of an ink liquid from the liquid surface of an ink liquid. With such a structure, the ejection and flight of ink liquid droplets vary greatly depending on the relative positional relationship between the ink liquid surface and the focused ultrasonic wave generating structure. For this reason, fine adjustment of the focused ultrasonic wave generating structure is essential. In particular, it is important to adjust the propagation direction of the liquid surface and the focused ultrasonic wave, adjust the liquid surface position and the focal length of the focused ultrasonic wave, and adjust the aperture where the liquid level is exposed and the focused position of the focused ultrasonic wave. . In addition, these adjustments vary depending on the type of ink liquid (for example, pigment ink, dye ink, etc.), particularly the viscosity thereof.

  The present invention has been made in view of the above circumstances, and a droplet flight evaluation system and a droplet that enable simple optimization of droplet ejection and flight in the design of a focused ultrasonic type inkjet recording head. An object is to provide a flight evaluation method.

  In order to achieve the above object, a droplet flight evaluation system according to the present invention includes a recording liquid holding unit that has an opening to hold a recording liquid, and the recording liquid is exposed to the liquid surface of the recording liquid that is exposed at the opening. Focused ultrasonic wave generating means for emitting focused ultrasonic waves from the inside of the liquid and discharging and flying droplets of the recording liquid from the liquid surface; and changing the arrangement of the focused ultrasonic wave generating means inside the recording liquid. A first position adjusting unit that adjusts a positional relationship between the focused ultrasonic wave generating unit and the liquid level; a flying droplet measuring unit that measures a droplet of the recording liquid ejected and flying from the liquid level; It has the composition which has.

  Further, the droplet flight evaluation method according to the present invention includes a focused ultrasonic wave generating means for radiating focused ultrasonic waves to the liquid surface of the recording liquid and ejecting and flying droplets of the recording liquid from the liquid surface. And the arrangement of the focused ultrasonic wave generating means inside the recording liquid is changed to evaluate the flying state of the droplets.

  With the configuration of the present invention, it is possible to easily optimize the ejection and flight of droplets in the evaluation of the design stage of a focused ultrasonic type inkjet recording head. Further, the accuracy of the evaluation data of the recording head structure is improved, and the optimization of the head structure in the manufacturing design of the recording head is facilitated.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating an example of a droplet flight evaluation system of the present embodiment. FIG. 2 is a longitudinal sectional view for explaining optimization of ejection and flight of ink liquid droplets. FIG. 3 is an AA arrow view of FIG. FIG. 4 is a longitudinal sectional view for explaining another optimization of the ejection and flight of the droplet. Here, the same or similar parts including those in FIG.

  As shown in FIG. 1, the droplet flight evaluation system of the present embodiment includes, as main components, a first position adjustment mechanism 1, a second position adjustment mechanism 2, a rotating drum 3, an imaging device 4, and focused ultrasound generation. A structure 5 and an ink holding chamber 6 are provided. The droplet flight evaluation system is collectively controlled by a control device such as a personal computer (PC).

  The first position adjustment mechanism 1 includes an adjustment main body 1a, a first adjustment arm 1b, a second adjustment arm 1c, and a third adjustment arm 1d. These adjusting arms are made of, for example, cylindrical ceramics, and the focused ultrasonic wave generating structure 5 including the piezoelectric element and the acoustic lens is fixedly held by a third adjusting arm 1d, and recording liquid holding means is provided. The position is adjusted by changing the arrangement in the ink liquid 12 of the ink holding chamber 6.

  The drive mechanism in the adjustment body 1a allows the first adjustment arm 1b to adjust the position by moving and displacing the focused ultrasonic wave generation structure 5 in the X-axis, Y-axis, and Z-axis directions shown in FIG. Yes. Similarly, the second adjustment arm 1c adjusts the position by applying a rotational direction α about the X axis as a rotation axis to the focused ultrasonic wave generation structure 5 and rotationally displacing it. The third adjustment arm 1d can be adjusted in position by applying a rotational direction β with the Y axis as a rotation axis to the focused ultrasonic wave generating structure 5 and rotationally displacing it. Here, the first adjusting arm 1b is moved and displaced in the X-axis, Y-axis, and Z-axis directions by a known motor and ball screw mechanism, and the accuracy of the displacement is about +/− 1 μm. The second adjustment arm 1c and the third adjustment arm 1d are rotationally displaced by a known motor and rotation adjustment mechanism, and the accuracy of the rotational displacement is about +/− 1 mrad (milliradian).

  Further, a drive circuit 15 for the piezoelectric element 10 of the focused ultrasonic wave generating structure 5 serving as a focused ultrasonic wave generating means is attached in the adjustment body 1a. The drive circuit 15 is connected to the focused ultrasonic wave generation structure 5 by wires arranged in the cylinders of the first adjustment arm 1b, the second adjustment arm 1c, and the third adjustment arm 1d. Yes.

  The second position adjustment mechanism 2 is a table made of, for example, a metal plate or a ceramic plate, and is configured to fix and hold the first position adjustment mechanism 1 and the ink holding chamber 6 on the surface thereof. The second position adjusting mechanism 2 adjusts the position of the ink holding chamber 6 together with the first position adjusting mechanism 1, and rotates with the liquid level of the ink liquid exposed at the opening provided in the upper lid of the ink holding chamber 6. The positional relationship of the drum 3 is adjusted. Then, the liquid surface of the ink liquid is set to be directly below the rotary drum, and the distance from the recording medium wound around the rotary drum 3 is adjusted.

  The rotating drum 3 rotates at a predetermined speed and can move in the Y-axis direction shown in FIG. The image dots formed on the storage medium wound around the surface of the rotary drum 3 by a large number of droplets that protrude from the surface of the ink liquid 12 and fly and land are recorded on the recording medium by the rotation and movement of the rotary drum 3. Are formed at different locations. In this way, the shape of each image point can be discriminated and measured, and the shape of the image dot after landing on the recording medium of the droplet can be grasped. It becomes possible to evaluate the flight state of the.

  The imaging device 4 is composed of, for example, a CCD camera having a strobe function, and measures droplets ejected from the surface of the ink liquid 12 by the focused ultrasonic wave generation structure 5 and flying toward the recording medium on the surface of the rotating drum 3. . Note that the strobe function unit and the camera unit may be integrated, or may be separated and arranged with the observation target interposed therebetween. By using this flying droplet measuring means, it is possible to grasp the flying state such as the particle size of the droplet, the number of droplets flying per unit time, the flying direction and the flying speed of the droplet, and the optimum droplet It becomes possible to evaluate the flight state of the.

  In the evaluation at the design stage of the focused ultrasonic type inkjet recording head using the droplet flight evaluation system, the liquid level of the ink liquid 12 and the focused ultrasonic wave generation structure 5 are used by using the first position adjusting mechanism 1. The relative positional relationship between the two can be freely changed with high accuracy. Then, in each of the changed positional relationships, the focused ultrasonic wave generating structure 5 is driven, and droplets are ejected and ejected from the liquid surface of the ink liquid 12, so that a dot is applied to the recording medium on the rotating drum 3. Is formed.

  Then, the measurement of the dot formation state by the rotating drum 3 as described above and the measurement of the flying state of the droplet by the imaging device 4 are performed, and between the liquid surface of the ink liquid 12 and the focused ultrasonic wave generation structure 5. Evaluation data with high accuracy in the positional relationship can be obtained. In this way, the optimum positional relationship between the liquid surface of the ink liquid and the focused ultrasonic wave generating structure in the focused ultrasonic type ink jet recording head can be obtained.

  Adjustment of the positional relationship between the liquid surface of the ink liquid 12 and the focused ultrasonic wave generation structure 5 using the first position adjustment mechanism 1, ejection of droplets by the focused ultrasonic wave generation structure 5, and their flight are as follows: It is controlled by a control device such as the PC. The measurement data of the dot formation state and the flying state of the droplet are processed and evaluated by the PC.

  Next, the operation mechanism of the droplet flight evaluation system of the present embodiment for obtaining the optimum positional relationship between the liquid surface of the ink liquid 12 and the focused ultrasonic wave generation structure 5 will be described with reference to FIGS. I will explain.

  First, regarding the positional relationship between the liquid surface of the ink liquid 12 and the focused ultrasonic wave generation structure 5, movement in the X-axis, Y-axis, and Z-axis directions shown in FIG. A burst wave having a predetermined voltage value is applied to the piezoelectric element 10 of the focused ultrasonic wave generation structure 5 by the drive circuit 15 in the adjustment main body 1 a of the first position adjustment mechanism 1, and the focused ultrasonic wave is focused in the ink liquid 12. A sound wave 14 is generated. In the state in which the focused ultrasonic wave 14 is generated as described above, as described with reference to FIG. 1, the focused ultrasonic wave generation structure 5 becomes μm by the movement of the first adjustment arm 1b in the X-axis, Y-axis, and Z-axis directions. The position is adjusted in units.

  As shown in FIG. 2, the acoustic lens 11 constituting the focused ultrasonic wave generation structure 5 fixedly held on the third adjustment arm 1d by the movement of the first adjustment arm 1b in the Z-axis direction is The position is displaced. Then, the positional relationship between the focal position of the focused ultrasound 14 and the liquid level 13 changes. For this reason, in the meniscus 7 that rises in a conical shape from the liquid surface 13 due to the pressure energy of the focused ultrasonic wave 14, the shape such as the size or the height thereof changes. Further, as the shape of the meniscus 7 changes, the flying state of the droplets 8 that are separated and discharged from the apex of the meniscus 7 (particle size, number of droplets flying per unit time, droplet flying direction) And flying speed etc. will change.

  Then, the droplet 8 lands on a recording medium 9 such as a recording sheet wound around the rotary drum 3 to form an image point. The image dots formed in this way are formed at different locations on the recording medium 9 by the rotation and movement of the rotary drum 3 as described above. For this reason, the shape of these dot points can be discriminated and measured, and the optimum dot dot formation state or flight state of the droplet can be found. Further, as described above, the flying state of the droplet is measured by the imaging device 4. In this way, the distance in the Z-axis direction between the acoustic lens 11 and the liquid surface 13 for forming an optimum droplet is adjusted. This optimum distance in the Z-axis direction does not necessarily match the focal length of the focused ultrasonic wave 14. This distance varies greatly depending on the type of ink liquid (recording liquid), particularly its viscosity.

  In exactly the same manner, as shown in FIG. 3, the focused ultrasonic wave generation structure 5 fixed and held on the third adjustment arm 1d is constituted by the movement of the first adjustment arm 1b in the X-axis and Y-axis directions. The acoustic lens 11 is displaced in the X-axis and Y-axis directions. And the position changes within the opening 17 of the meniscus 7 to be generated. Here, as described above, the diameter of the opening 17 is, for example, 1.5 mm or less. Due to the change in the position of the meniscus 7 in the opening 17, the flying state of the droplet 8 that is separated and discharged from the vertex of the meniscus changes. This is because the surface tension of the liquid surface 13 of the ink liquid 12 changes at a position in the opening 17 due to the influence of the upper lid 16.

  Therefore, the opening 17 shown in FIG. 3 is arranged in the central region of the concave surface 11a formed in the acoustic lens 11 whose effective surface has an aperture of about 3 mm as described above. It is preferable to adjust the movement in the axial direction. Such adjustment can be easily performed through measurement of an image point formed by landing on the recording medium 9 wound around the rotating drum 3 as described above, and measurement of a droplet flight state by the imaging device 4. Normally, when the meniscus 7 is positioned at the center of the opening 17, the influence of the upper lid 16 is minimized, the surface tension at the liquid surface is the lowest, and the flying speed of the droplet ejected from the liquid surface is the largest. Become.

  Next, in the positional relationship between the liquid surface of the ink liquid 12 and the focused ultrasonic wave generating structure 5, a rotation direction α with the X axis shown in FIG. 1 or 3 as the rotation axis is given to the focused ultrasonic wave generating structure 5. A case where the position is adjusted will be described. Also in this case, a burst wave having a predetermined voltage value is applied to the piezoelectric element 10 of the focused ultrasonic wave generating structure 5 by the drive circuit 15 in the adjustment main body 1a of the first position adjustment mechanism 1, and the ink liquid 12 A focused ultrasound 14 is generated therein. In the state where the focused ultrasonic wave 14 is generated in this way, as described in FIG. 1, the position of the focused ultrasonic wave generating structure 5 is adjusted in units of mrad by the rotational drive of the X axis of the second adjustment arm 1c. .

  As shown in FIG. 4, the concave surface 11a of the acoustic lens 11 constituting the focused ultrasonic wave generation structure 5 fixedly held on the third adjustment arm 1d by the rotational drive of the X axis of the second adjustment arm 1c is as follows. The relative positional relationship of the ink liquid 12 with respect to the liquid surface 13 is displaced. Then, since the angle formed by the propagation direction of the focused ultrasonic wave 14 and the liquid level 13 changes, the shape of the meniscus 7 discharged from the liquid level 13 changes. Along with the shape change of the meniscus 7, the flight direction and the flight speed of the droplet 8 flying separately from the apex of the meniscus 7 change greatly.

  These droplets 8 land on the example recording medium 9 wound around the rotating drum 3 in the same manner as described with reference to FIG. The shape of the image dots formed in this way is measured, and an evaluation is made as to whether or not the image is in an optimal droplet image formation state. Further, as described above, the flying state of the droplet is measured by the imaging device 4. The optimum rotation direction α is adjusted to a rotation angle at which the droplet 8 flies vertically from the liquid surface 13.

  Exactly in the same manner, the relative positional relationship between the concave surface 11a of the acoustic lens 11 and the liquid surface 13 of the ink liquid 12 is displaced by driving in the rotational direction β by the third adjusting arm 1d. Then, the angle formed by the propagation direction of the focused ultrasonic wave 14 and the liquid surface 13 changes in the same manner as in the case of driving in the rotation direction α. For this reason, the shape of the meniscus 7 discharged from the liquid surface 13 changes. Then, the flying state of the droplet 8 that is separated and discharged from the apex of the meniscus 7 changes greatly.

  Therefore, these droplets 8 are evaluated by the image points formed by landing on the recording medium 9 wound around the rotary drum 3 and the imaging device 4 in the same manner as in the case of driving in the rotational direction α. . The optimum rotation direction β is adjusted to a rotation angle at which the droplet 8 flies vertically from the liquid surface 13.

  In this way, the position is adjusted so that the particle size of the droplets becomes a desired particle size, and the number of droplets flying per unit time of the droplets becomes a desired number. Further, the position is adjusted so that the flying direction of the droplet is perpendicular to the liquid surface and the flying speed of the droplet is within a predetermined range.

  In the above embodiment, the case where the acoustic lens 11 is a concave lens has been described. However, the case where the acoustic lens 11 is constituted by a Fresnel lens is exactly the same. Further, in the adjustment of the positional relationship between the ink liquid level 13 and the focused ultrasonic structure 5, the rotation direction θ shown in FIG. 2 may be adjusted. The second position adjustment mechanism 2 is preferably a drive table that performs movement displacement in the X, Y, and Z axis directions and rotational displacement similar to the first position adjustment mechanism 1.

  In the above embodiment, the relative arrangement between the focused ultrasonic wave generating structure 5 and the liquid surface 13 of the ink liquid 12 is very easily changed in the evaluation of the design stage of the inkjet recording head using the focused ultrasonic waves. Can do. The arrangement of the droplets 8 can be changed in various ways to measure in detail the flying state of the droplets 8 ejected from the liquid surface 13 and flying. In this way, the accuracy of the evaluation data of the recording head structure is greatly improved. Then, optimization of the head structure in the manufacturing design of the recording head can be easily performed.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention.

1 is a schematic elevation view showing an example of a droplet flight evaluation system according to an embodiment of the present invention. The longitudinal cross-sectional view for demonstrating the optimization of discharge and flight of the droplet which concerns on embodiment of this invention. The AA arrow directional view described in FIG. The longitudinal cross-sectional view for demonstrating another optimization of the discharge and flight of the droplet which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of an ink jet recording head for explaining the present invention, wherein (a) is a longitudinal sectional view of a focused ultrasonic storage head in which a concave acoustic lens is coupled to a piezoelectric element, and (b) is a Fresnel lens. FIG. 3 is a longitudinal sectional view of a focused ultrasonic type storage head in which is coupled to a piezoelectric element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st position adjustment mechanism, 1a ... Adjustment main body, 1b ... 1st adjustment arm, 1c ... 2nd adjustment arm, 1d ... 3rd adjustment arm, 2 ... 2nd position adjustment mechanism, 3 ... Rotation Drum, 4 ... imaging device, 5 ... focused ultrasound generating structure, 6 ... ink holding chamber, 7 ... meniscus, 8 ... droplet, 9 ... recording medium, 10 ... piezoelectric element, 10a, 10b ... electrode, 11 ... acoustic Lens, 11a ... concave surface, 12 ... ink liquid, 13 ... liquid surface, 14 ... focused ultrasonic wave, 15 ... drive circuit, 16 ... upper lid, 17 ... opening

Claims (8)

A recording liquid holding means for holding a recording liquid with an opening;
Focused ultrasound generating means for emitting focused ultrasound from the inside of the recording liquid to the liquid surface of the recording liquid exposed at the opening, and discharging and flying the recording liquid droplets from the liquid surface;
A first position adjusting unit that adjusts a positional relationship between the focused ultrasonic wave generating unit and the liquid surface by changing an arrangement of the focused ultrasonic wave generating unit inside the recording liquid;
Flying droplet measuring means for measuring droplets of the recording liquid ejected from the liquid surface and flying;
A droplet flight evaluation system characterized by comprising:   2. The droplet flight evaluation system according to claim 1, wherein the first position adjusting unit adjusts a radiation direction of the focused ultrasonic wave with respect to a liquid surface of the recording liquid.   3. The focused ultrasonic wave generation unit includes a piezoelectric element that is acoustically connected to the recording liquid and an acoustic lens that focuses ultrasonic waves generated from the piezoelectric element. The droplet flight evaluation method described.   4. The droplet flying evaluation system according to claim 1, wherein the flying droplet measuring means includes an imaging device having a strobe function.   5. The droplet flight evaluation system according to claim 1, further comprising a rotating drum around which a recording medium on which the droplet ejected and ejected from the liquid surface lands is wound.   6. The droplet flight evaluation system according to claim 5, wherein the rotating drum moves in a direction of a rotation axis.   A second position for adjusting the positional relation between the liquid surface exposed at the opening of the recording liquid holding means and the rotary drum while fixing the positional relation between the recording liquid holding means and the first position adjusting means. The droplet flight evaluation system according to claim 5 or 6, further comprising an adjusting unit. A focused ultrasonic wave generating means for radiating focused ultrasonic waves to the liquid surface of the recording liquid and discharging and flying droplets of the recording liquid from the liquid surface is disposed inside the recording liquid,
A droplet flight evaluation method, characterized in that the flying state of the droplet is evaluated by changing the arrangement of the focused ultrasonic wave generating means inside the recording liquid.

Images