JP2006116972A - Head spraying liquid medicine for lung inhalation, spraying apparatus equipped with the head and spraying method for the liquid medicine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharging head which discharges quite minute liquid droplets, for example, in the order of a sub pico liter or less. <P>SOLUTION: In a discharge port 4, an aperture part 7 is provided in a recessed position relative to a discharge port surface 5a forming an opening surface for the discharge port 4 of a discharge port plate 5. The aperture part constitutes a suddenly shrunk part in the cross sectioning area of the discharge port 4, in comparison with other parts. Furthermore, the liquid to be discharged is held to form meniscus 8 between the discharge port surface 5a and the aperture part 7 within the discharge port 4. Accordingly, the aperture part 7 is arranged within the liquid in the passage from a liquid flow path 3 to the discharge port surface 5a of the discharge port plate 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is suitably used for an inkjet head used for ejecting ink for recording in the inkjet recording field, an inhaler used for inhaling a liquid drug in the form of a mist in the medical field, The present invention relates to a liquid discharge head that discharges liquid as fine droplets.

  Conventionally, liquid discharge heads that discharge liquid as fine droplets have been widely used as inkjet heads in the field of inkjet recording. Ink-jet heads are required not only to eject droplets but also to have stability in the direction of droplet ejection. In conventional ink-jet heads, various proposals have been made to achieve this requirement. .

For example, Patent Document 1 discloses an ink jet head that forms a recess around an ejection port that ejects ink, thereby preventing ink contact between adjacent ejection ports and stably ejecting ink. ing. Patent Document 2 and Patent Document 3 have a discharge port forming member in which a recess is formed around the discharge port. The ink is treated on the inside of the recess and the surface of the discharge port forming member excluding the recess. There has been disclosed an ink jet head in which ink repellent treatment is performed and ink is ejected in a state where a meniscus is formed in a recess, thereby stably ejecting liquid droplets and improving recording quality.
Japanese Patent Laid-Open No. 5-77422 JP-A-5-193141 Japanese Patent Laid-Open No. 11-334069

  The demand for the recording quality of the ink jet head is further increased. In recent years, in particular, in order to make the granularity of the ink adhering to the recording medium inconspicuous, miniaturization of ejected droplets is required. However, the above-described conventional inkjet head has not necessarily been configured to achieve droplet miniaturization. If the droplet volume can be reduced to sub picoliter order or less, it can be applied not only to the ink jet recording field but also to other fields.

  An object of the present invention is to provide a liquid ejection head that ejects extremely small droplets, for example, in the sub-picoliter order or less.

  In order to achieve the above object, the present invention provides a liquid flow path, a discharge port forming member having a part of a wall of the liquid flow path and having a discharge port for discharging liquid as droplets, and the liquid An energy generating element that is provided at a position facing the discharge port on the wall of the flow path and generates discharge energy to be given to the liquid, and the discharge port of the discharge port forming member is provided in the discharge port. A throttle portion is provided at a position that is concave with respect to the opened surface, and the liquid is held in a form of a meniscus in the discharge port so that the throttle portion is located in the liquid, and the throttle portion Where c ≦ e and the height of the liquid flow channel in the facing direction between the discharge port and the energy generating element is e, the relationship c ≦ e is satisfied.

  It is preferable that the narrowed portion is provided at an intermediate position in the thickness direction of the discharge port forming member.

  Moreover, it is preferable that the opening diameter of the opening area of the throttle portion is changed with respect to the liquid ejection direction.

  Furthermore, it is preferable that the opening area of the throttle portion is formed by a plurality of pores.

  A heating element is preferably used as the energy generating element.

  As the liquid, a recording liquid used for ink jet recording or a medicine used for lung inhalation can be applied.

  In the liquid discharge head as described above, before the start of discharge, a meniscus is formed at the discharge port of the discharge port forming member, and the pores of the throttle portion are located in the liquid. When the energy generating element is driven for discharging the liquid, the liquid moves at least to the discharge port side.

  At this time, the liquid passes through the pores of the throttle portion when moving toward the discharge port. As a result, the movement speed of the liquid after passing through the pores is much faster than before the passage, and the flow velocity corresponding to the pores is relatively faster in moving the liquid in the recess opening the discharge port. .

  Accordingly, the central portion of the meniscus at the discharge port, which is opposed to the pores, rises and droplets are discharged. That is, since the entire liquid in the recess opening the discharge port is not discharged, it is possible to discharge a very small droplet.

  In addition, since the liquid has accumulated in the recess that opens the discharge port so that the pores are in the liquid, the liquid in the pores will not clog due to drying, and good liquid droplets will be discharged from the start of discharge. It can be discharged.

  As described above, according to the present invention, the liquid flow path, the discharge port forming member that forms a part of the wall of the liquid flow path and has a discharge port for discharging the liquid as droplets, An energy generating element that is provided at a position facing the discharge port on the wall of the liquid flow path and generates discharge energy to be given to the liquid, wherein the discharge port of the discharge port forming member is A constriction is provided at a position that is concave with respect to the opened surface, and the meniscus of the liquid is formed in the discharge port so that the pores of the constriction are located in the liquid. Since the central part facing the pores rises and droplets are ejected, it is possible to eject extremely small droplets without leading to the overall ejection of the liquid in the recess opening the ejection port. is there.

  In addition, since the meniscus is formed in the recess opening the discharge port and the pores are located in the liquid, the liquid in the pores does not clog due to drying, and a good liquid from the start of discharge. Drops can be ejected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A and 1B show a liquid discharge head according to an embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line XX.

  In the liquid discharge head shown in FIG. 1, a heater 1 that is an energy generating element for discharging liquid is provided on a substrate 2. The heater 1 is disposed corresponding to the liquid flow path 3. In FIG. 1, only one heater 1 and one liquid flow path 3 are shown, but actually, a plurality of heaters 1 are arranged on one substrate 2, and the liquid flow path 3 is provided for each heater 1. Has been placed. The energy generation element is not limited to an electrothermal conversion element such as a heater, and may be a vibration energy generation element such as a piezo element.

  The liquid flow path 3 includes a discharge port plate 5 having a discharge port 4 for discharging liquid as droplets, a substrate 2, and a distance defining member 6 that defines a distance between the discharge port plate 5 and the substrate 2. It is surrounded and composed.

  The discharge port 4 has a constricted portion 7, that is, the cross-sectional area of the discharge port 4 is compared with other portions at a position that is concave with respect to the discharge port surface 5 a that is the surface on which the discharge port 4 of the discharge port plate 5 opens. Thus, a sharply narrowed portion is provided. Further, the liquid to be discharged is held in the discharge port 4 by forming a meniscus 8 between the discharge port surface 5 a and the narrowed portion 7. Therefore, the throttle portion 7 is located in the liquid in the path from the liquid flow path 3 to the discharge port surface 5 a of the discharge port plate 5.

  Here, specific dimensions of the liquid discharge head shown in FIG.

  The heater 1 is a 10 μm square, the opening diameter a of the discharge port 4 on the discharge port surface 5a is 10 μm, the hole diameter b of the fine hole 7a, which is the opening region in the throttle portion 7, is 3 μm, and the thickness c of the throttle portion 7 is It was 1 μm. Further, the height d from the upper surface of the restricting portion 7 to the discharge port surface 5a of the discharge port plate 5 is 4 μm, the height e of the liquid flow path 3 (the height of the interval defining member) is 5 μm, and the discharge port plate 5 The thickness f was 5 μm.

  The liquid discharge head has a relationship of c ≦ e between the thickness c of the throttle portion 7 and the height e of the liquid flow path 3. In the case of the liquid discharge head shown in FIG. 1, as described above, it is understood that c = 1 μm and e = 5 μm, and the relationship c ≦ e is satisfied.

  Next, the discharge operation of the liquid discharge head having such a configuration will be described. FIG. 2 shows a state of liquid ejection when the head of the form shown in FIG. 1 is driven.

  Before starting the discharge, as shown in FIG. 1, a meniscus 8 is formed at the discharge port 4 of the discharge port plate 5, and the pores 7a of the throttle portion 7 are located in the liquid. When a voltage is applied to the heater 1 for discharging the liquid, the heater 1 generates heat as shown in FIG. 2A, and the liquid in the liquid flow path 3 in contact with the surface of the heater 1 is heated. Bubbles are generated.

  When bubbles are generated due to film boiling, the volume of the bubbles grows sharply, so that the liquid moves downstream (discharge port 4 side) and upstream (liquid supply side).

  At this time, the liquid passes through the pore 7 a of the throttle portion 7 when moving toward the discharge port 4. As a result, the movement speed of the liquid after passing through the pores 7a is remarkably faster than before the passage, and the flow rate corresponding to the pores 7a is relatively high in the movement of the liquid in the recess opening the discharge port 4. Get faster.

  Therefore, as shown in FIGS. 2B to 2D, the central portion of the meniscus 8 in the discharge port 4 facing the pores 7a rises and the droplet 10 is discharged. That is, since the entire liquid in the recess opening the discharge port 4 is not discharged, it is possible to discharge a very small liquid droplet (0.014 pl).

  In addition, since the liquid is accumulated in the recess that opens the discharge port 4 so that the pore 7a is located in the liquid, the liquid in the pore 7a is not clogged by drying, and is good from the start of discharge. Liquid droplets can be discharged.

  FIG. 3 shows a first modification of the liquid discharge head shown in FIG. In the example shown in this figure, the diameter of the pore 7a formed by the throttle portion 7 is tapered from the liquid flow path 3 side to the discharge port surface 5a side as shown in FIG. Is different. As described above, even if the narrowed portion 7 is tapered, the same effect as the liquid discharge head shown in FIG. 1 can be obtained as long as the relationship of c ≦ e is satisfied. In the example shown in FIG. 3, the pore diameter 7a is shown in which the hole diameter becomes narrower from the liquid flow path 3 side toward the discharge port surface 5a side. However, the hole diameter of the pore 7a of the throttle portion 7 is the discharge port surface 5a. Even if the diameter of the narrowed portion 7 is narrowed from the side toward the liquid flow path 3 or the diameter of the narrow hole 7a of the throttle portion 7 is narrowed once from the liquid flow path 3 toward the discharge port surface 5a, and then expands again. Good. Further, corners may be taken in the pores 7 a of the narrowed portion 7. Furthermore, the shape of the pore 7a is arbitrary as long as the pore diameter of the pore 7a of the throttle portion 7 changes in the liquid discharge direction.

  FIG. 4 shows a second modification of the liquid ejection head shown in FIG. In the example shown in this figure, the position of the throttle portion 7 is set between the surface of the discharge port plate 5 where the discharge port 4 is opened and the upper surface of the interval defining member 6 that defines the height of the liquid flow path 3. 1 is different from that shown in FIG. As described above, even if the position of the throttle portion 7 in the discharge port 4 is changed within a range that is concave with respect to the discharge port surface 5a, the relationship shown in FIG. The same effect as the liquid discharge head can be obtained.

  FIG. 5 shows a third modification of the liquid discharge head shown in FIG. In the example shown in this figure, a plurality of pores 7 a formed by the throttle portion 7 are provided corresponding to one heater 1. As described above, by providing the discharge ports 4 with the plurality of pores 7a, in addition to the above-described effects, a plurality of droplets can be simultaneously discharged from one discharge port 4.

  The first to third modified examples described above can be applied to the liquid discharge head of the present invention in an appropriate combination as well as being applied alone.

  The liquid discharge head of the present invention can be suitably used for an apparatus for discharging (including spraying) minute droplets. Specific examples thereof include an ink jet recording head in the ink jet recording field and a medicine inhaling head in the medical field.

  When the liquid discharge head of the present invention is used as an ink jet recording head, the discharge ports are arranged in one or a plurality of rows, and the discharged liquid is used to prevent ink or ink bleeding on the recording sheet. In addition, a recording liquid such as a surface treatment liquid that adheres to the recording sheet prior to the ink is used. By appropriately setting the arrangement direction and the arrangement length of the discharge ports, it can be used as an ink jet recording head used in a serial type ink jet recording apparatus, or an ink jet recording head used in a line type ink jet recording apparatus. You can also. Further, in the case of an ink jet recording head used in a serial type ink jet recording apparatus, it is possible to adopt a cartridge form in which a liquid discharge head and a tank for storing a recording liquid supplied to the head are integrated or separable. .

  When the liquid ejection head of the present invention is used as a medicine inhalation head, the liquid ejection head is connected to a medicine dispenser, and the liquid to be ejected includes proteins such as insulin, human growth hormone, and gonadotropin. Formulations, nicotine, or anesthetics are used.

1 shows a liquid discharge head according to one embodiment of the present invention, in which (a) is a plan view and (b) is a cross-sectional view taken along line XX. It is a figure which shows the mode of a liquid discharge when the head of the form of FIG. 1 is driven. FIG. 10 is a view showing a first modification of the liquid ejection head in the form of FIG. 1. FIG. 10 is a diagram showing a second modification of the liquid ejection head in the form of FIG. 1. FIG. 10 is a diagram showing a third modification of the liquid ejection head in the form of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater 2 Board | substrate 3 Liquid flow path 4 Discharge port 5 Discharge port plate 6 Space | interval regulating member 7 Constriction part 7a Fine hole 8 Meniscus 9 Bubble 10 Droplet a: Opening diameter b of the discharge port of the discharge port plate: Formed by the constriction part C: Diameter of the narrowed portion c: Thickness of the throttle portion d: Height from the upper surface of the throttle portion to the surface where the discharge port of the discharge port plate is opened e: Height of the liquid flow path (height of the spacing regulating member)
f: Thickness of discharge port plate

Claims (7)

A liquid flow path;
A part of the wall of the liquid flow path, and a discharge port forming member having a discharge port for discharging liquid as droplets;
An energy generating element that is provided at a position facing the discharge port of the wall of the liquid flow path and generates discharge energy to be given to the liquid;
The discharge port is provided with a throttle portion at a position that is concave with respect to the surface of the discharge port forming member on which the discharge port is opened.
The liquid is held by forming a meniscus in the discharge port so that the throttle portion is located in the liquid, and
When the thickness of the throttle part is c, and the height of the liquid channel in the facing direction of the discharge port and the energy generating element is e,
A liquid discharge head satisfying a relationship of c ≦ e.   The liquid ejection head according to claim 1, wherein the throttle portion is provided at an intermediate position in the thickness direction of the ejection port forming member.   3. The liquid discharge head according to claim 1, wherein an opening diameter of an opening region of the throttle portion is changed with respect to a discharge direction of the liquid.   4. The liquid ejection head according to claim 1, wherein the opening area of the throttle portion is formed by a plurality of pores. 5.   The liquid ejection head according to claim 1, wherein the energy generating element is a heat generating element.   The liquid discharge head according to claim 1, wherein the liquid is a recording liquid used for inkjet recording. The liquid discharge head according to claim 1, wherein the liquid is a medicine used for lung inhalation.

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