JP6157129B2 - LIQUID DISCHARGE DEVICE, LIQUID DISCHARGE DEVICE MANUFACTURING METHOD, METAL WIRING MANUFACTURING METHOD, AND COLOR FILTER MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a liquid ejection device in which a pressure chamber is formed by being partitioned by a partition wall made of a piezoelectric body, a method for manufacturing the liquid ejection device, a method for manufacturing a metal wiring, and a method for manufacturing a color filter .

  As a liquid discharge head that is a liquid discharge apparatus, a liquid discharge head that ejects droplets by changing the pressure of ink in a pressure chamber, generating a flow in the ink, and discharging the ink from a nozzle is widely used. In particular, drop-on-demand heads are most commonly used. There are two main methods for applying pressure to ink. That is, a method of changing the pressure of the ink by changing the pressure in the pressure chamber by a drive signal to the piezoelectric element, and a method of generating a bubble in the pressure chamber by a drive signal to the resistor and applying pressure to the ink.

  A liquid discharge head using a piezoelectric element can also be manufactured relatively easily by machining a bulk piezoelectric material. Further, there is an advantage that inks of a wide range of materials can be selectively applied to a recording medium with relatively few ink restrictions. From such a viewpoint, in recent years, there have been many attempts to use the liquid discharge head for industrial purposes such as color filter manufacturing and wiring formation.

  Of the piezoelectric liquid discharge heads used for industrial purposes, the share mode method is often employed. The shear mode method uses shear deformation by applying an electric field in an orthogonal direction to a piezoelectric body subjected to polarization treatment. The piezoelectric body to be deformed is a partition wall formed by processing ink grooves and the like with a dicing blade on a bulk piezoelectric material subjected to polarization treatment. An electrode pair for driving the piezoelectric body is formed on both side surfaces of the partition wall, and a liquid ejection head is configured by forming a nozzle plate on which nozzles are formed and an ink supply system (see Patent Document 1). ).

  The share mode liquid discharge head can be manufactured relatively easily, but in order to obtain a desired discharge speed, the piezoelectric body is shear-deformed by a voltage (potential difference) applied to both sides of the partition wall made of the piezoelectric body, It is necessary to control the pressure applied to the liquid in the pressure chamber.

  The discharge performance of a piezoelectric liquid discharge head is generally expressed by the relationship between voltage and discharge speed, and it is known that the discharge speed is proportional to the voltage. In order to obtain a liquid discharge head with low power consumption and good discharge speed control, droplets can be discharged at a low voltage, and the rate of change in discharge speed with respect to voltage (hereinafter referred to as “voltage sensitivity”) is reduced. It is necessary to.

  Since the discharge speed is proportional to the pressure applied to the liquid in the pressure chamber, it can be controlled by adjusting the pressure applied to the liquid depending on the material of the piezoelectric body, the width and height of the partition wall and the pressure chamber. For example, in order to increase the pressure applied to the liquid, it is effective to increase the displacement volume of the pressure chamber by narrowing the width of the pressure chamber or increasing the height of the pressure chamber.

On the other hand, the relationship between the displacement volume and the structure of the partition wall and the pressure chamber is as follows: displacement volume ΔVol, piezoelectric constant d ₁₅ , pressure chamber height H, partition wall width T, voltage V, and pressure chamber length z. ΔVol = (d ₁₅ × H × z × V) ÷ (4 × T).

Japanese Patent Publication No. 6-6375

  However, if an attempt is made to increase the displacement volume of the pressure chamber by changing the width of the partition wall or the height of the pressure chamber over the entire longitudinal direction, the rate of change of the displacement volume with respect to the voltage increases from the above relational expression. Since the displacement volume and the pressure applied to the liquid are in a proportional relationship, as a result, the rate of change in voltage with respect to the pressure applied to the liquid also increases. In other words, in order to discharge droplets at a low voltage, simply adjusting the width of the pressure chamber and the height of the pressure chamber to increase the pressure applied to the liquid in the pressure chamber increases the voltage sensitivity of the discharge speed. As a result, the controllability of the discharge speed of the liquid drops.

  In particular, when the diameter of the nozzle is reduced to, for example, 5 [μm] to 15 [μm] in order to eject micro droplets, the distance between the nozzle wall surface and the center of the nozzle is reduced, so that viscous resistance and surface tension are reduced. And the flow velocity of the liquid tends to concentrate at the center of the nozzle. For this reason, the liquid column formed in the discharge direction from the nozzle is hardly broken. Therefore, when the liquid column is broken and droplets are formed, the kinetic energy stored in the central portion of the nozzle is large, and therefore the droplet discharge speed is increased. In other words, by reducing the diameter of the nozzle, the pressure applied to the liquid in the pressure chamber, that is, the rate of change in the droplet discharge speed (voltage sensitivity) with respect to the voltage applied to the electrode pair becomes steeper, and the droplet discharge Speed controllability is further reduced.

Accordingly, the present invention provides a liquid ejection apparatus , a liquid ejection apparatus manufacturing method, a metal wiring manufacturing method using the liquid ejection apparatus, and a color filter manufacturing method that improve the controllability of the droplet ejection speed.

  In the present invention, the first substrate and the second substrate facing each other, and the first substrate and the second substrate are arranged in parallel with a gap in the width direction perpendicular to the height direction. A plurality of partition walls made of a piezoelectric body that form a plurality of pressure chambers extending in the direction of a first end in the longitudinal direction of each pressure chamber, and each nozzle connected to each pressure chamber And a common liquid chamber connected to the plurality of pressure chambers and disposed on the side of the second end opposite to the first end in the longitudinal direction of each pressure chamber. The common liquid chamber forming member, and each partition wall portion is divided into a movable region to which an electric field for shear deformation is applied at the nozzle side portion and a non-movable region to which the electric field is not applied at the common liquid chamber side portion. , Arranged on both side surfaces of each partition wall so as to face each other across the movable region. A plurality of electrode pairs, and each pressure chamber has a cross-sectional area of a cross section along a plane perpendicular to the longitudinal direction at the second end, and the pressure chamber has a cross-sectional area on the boundary between the movable region and the non-movable region. The first boundary point closest to the first end is formed so as to be wider than a cross-sectional area of a cross section along a plane perpendicular to the longitudinal direction.

  According to the present invention, the flow of liquid from the pressure chamber toward the common liquid chamber is increased during liquid discharge, so that the flow of liquid toward the nozzle is suppressed, and the rate of change in the droplet discharge speed with respect to the pressure applied to the liquid is reduced. Therefore, the controllability of the droplet discharge speed is improved.

1 is an exploded schematic diagram illustrating an inkjet head as an example of a liquid ejection head that is a liquid ejection apparatus according to a first embodiment of the present invention. FIG. It is a cross-sectional schematic diagram of the ink flow path showing the flow of ink in the inkjet head. It is a fragmentary perspective view of a discharge unit. It is a fragmentary sectional view of a discharge unit. It is a fragmentary perspective view which shows a part of discharge unit. It is a schematic diagram for demonstrating the displacement of a partition part at the time of applying a voltage to each electrode, and a deformation | transformation of a pressure chamber. It is a schematic diagram of the part except a 1st board | substrate in the discharge unit. It is a schematic diagram of a pressure chamber. It is a model for demonstrating operation | movement of the inkjet head at the time of ink discharge. It is a figure for demonstrating the manufacturing method of an inkjet head. It is a figure for demonstrating the manufacturing method of an inkjet head. It is a figure for demonstrating the manufacturing method of an inkjet head. It is a figure for demonstrating the manufacturing method of an inkjet head. It is a figure for demonstrating the manufacturing method of an inkjet head. It is a schematic diagram of the pressure chamber of 2nd Embodiment of this invention. It is a schematic diagram of the pressure chamber of 3rd Embodiment of this invention. It is a schematic diagram of the pressure chamber of 4th Embodiment of this invention. It is a schematic diagram which shows the cross section of a discharge unit. 4 is a graph showing a relationship between an applied voltage and a droplet discharge speed in the inkjet heads of Examples, Comparative Examples 1 and 2; 6 is a graph showing the relationship between nozzle diameter and voltage sensitivity in the inkjet heads of Examples, Comparative Examples 1 and 2; It is a schematic diagram which shows the pressure chamber of the inkjet head in an Example. It is a graph which shows the relationship between the cross-sectional area ratio of a pressure chamber, and voltage sensitivity. It is a graph which shows the relationship between ratio of length and voltage sensitivity.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an exploded schematic view showing an ink jet head as an example of a liquid discharge head which is a liquid discharge apparatus according to the first embodiment of the present invention. The ink jet head 100 shown in FIG. 1 is a discharge in which a plurality of pressure chambers 1 and a plurality of dummy chambers 2 arranged in a line in a width direction B orthogonal to a longitudinal direction A2 parallel to the liquid discharge direction A1 are formed. A unit 10 is provided. A nozzle plate 30 as a nozzle member in which each nozzle 30 a is formed corresponding to each pressure chamber 1 is arranged on the surface (front surface) on the liquid discharge side of the discharge unit 10. The discharge unit 10 and the nozzle plate 30 are aligned and bonded so that the positions of the pressure chamber 1 and the nozzle 30a coincide (that is, the pressure chamber 1 and the nozzle 30a communicate with each other). Thereby, each nozzle 30 a is connected to each pressure chamber 1. The pressure chamber 1 penetrates from the front surface toward the liquid supply surface (back surface). The dummy chamber 2 is an air chamber that penetrates the front side but does not penetrate the liquid supply surface (back side).

  A manifold 40 serving as a common liquid chamber forming member, which is provided with an ink supply port 41 and an ink recovery port 42 communicating with an ink tank (not shown), is joined to the back side of the discharge unit 10. A plurality of front grooves 7 communicating with the respective dummy chambers 2 are formed on the front side of the discharge unit 10. A flexible substrate 50 is bonded to the upper surface of the discharge unit 10.

  FIG. 2 is a schematic cross-sectional view of the ink flow path showing the flow of ink in the inkjet head 100. FIG. 3 is a partial perspective view of the discharge unit 10, and FIG. 4 is a partial cross-sectional view of the discharge unit 10.

  As shown in FIG. 3, the discharge unit 10 has a height direction between two substrates 11 and 12 (a first substrate 11 and a second substrate 12) facing each other and between the first substrate 11 and the second substrate 12. And a plurality of partition walls 3 arranged in parallel in the width direction B orthogonal to C.

  The partition walls 3 are formed in a long shape, and a plurality of pressure chambers 1 and a plurality of dummy chambers 2 extending in the longitudinal direction A2 are formed by the plurality of partition walls 3. Each partition 3 is composed of a piezoelectric body polarized in the height direction C.

  Further, as shown in FIG. 4, the discharge unit 10 has a plurality of electrode pairs (a pair of electrodes) 13 that are arranged on both side surfaces in the width direction B of each partition wall portion 3 and that shear-deform each partition wall portion 3. ing. That is, each partition wall 3 is provided with an electrode pair 13. Specifically, in each partition wall portion 3, an electrode pair 13 including a signal electrode 14 and a signal electrode 15 is provided on each side surface in the direction orthogonal to the liquid discharge direction A1 (longitudinal direction A2), that is, in the width direction B. Is provided. The signal electrode 14 is disposed on the dummy chamber side, and the signal electrode 15 is disposed on the pressure chamber side.

  One surface 12 a of the second substrate 12 is continuously connected to the signal electrode 14, is electrically connected to the signal electrode 14, and is continuously connected to the signal electrode 15. An electrically conductive bottom electrode 18 is formed. In the dummy chamber 2, the bottom electrodes 17, 17 formed on both sides are separated by a groove portion 19 and are electrically insulated.

  The signal electrode 14 is electrically connected to the extraction electrode 4 through a front electrode formed in the front groove 7 shown in FIG. The signal electrode 15 is grounded. When a voltage is applied to these electrode pairs 13, an electric field is applied to the partition wall portion 3 in a direction orthogonal to the polarization direction (width direction B), and the partition wall portion 3 is subjected to shear deformation in the width direction B. Function as. Specifically, the signal electrode 15 is set to the ground potential, and a voltage is applied to the signal electrode 14 with respect to the signal electrode 15. Since the electrode 15 in the pressure chamber 1 has a ground potential, a conductive liquid can be used.

  As shown in FIG. 2, a nozzle plate 30 is disposed on the first end 1 a side in the longitudinal direction A <b> 2 that is the liquid discharge side of the pressure chamber 1. On the other hand, on the liquid supply side of the pressure chamber 1, on the side of the second end 1b in the longitudinal direction A2 opposite to the first end 1a, the manifold 40 is disposed, and a common liquid chamber 43 is formed. ing. The common liquid chamber 43 is connected to each pressure chamber 1. Ink I is supplied to the common liquid chamber 43 from an ink tank (not shown) through the ink supply port 41. The ink I supplied to the common liquid chamber 43 is filled in each pressure chamber 1. Then, when the electric field is applied in the direction orthogonal to the polarization direction by the electrode pair 13, the partition wall 3 is sheared and the volume of the pressure chamber 1 is changed. Thereby, the ink (ink droplet) I which is a liquid (droplet) is ejected from the nozzle 30a.

  In the present embodiment, as shown in FIG. 4, the plurality of partition walls 3 are formed at intervals in the width direction B so as to protrude from one surface 12 a of the second substrate 12. That is, the plurality of partition walls 3 are protruded from the one surface 12a with an interval in the width direction B. And the front-end | tip part 3a of each partition part 3 and the one surface 11a of the 1st board | substrate 11 are joined by the adhesive agent 16, and the pressure chamber 1 and the dummy chamber 2 are partitioned off by the partition part 3, and the width direction B Are alternately formed. That is, a dummy chamber 2 partitioned by the partition walls 3 is formed between two adjacent pressure chambers 1, 1 among the plurality of pressure chambers 1. The dummy chamber 2 is an air chamber that is not connected to the common liquid chamber 43. In other words, the pressure chamber 1 and the dummy chamber 2 are spaces partitioned by the partition walls 3, that is, spaces surrounded by the partition walls 3, the second substrate 12, and the first substrate 11.

  The cross-sectional area of the cross section along the plane perpendicular to the longitudinal direction A2 of the pressure chamber 1 is H × W, where H is the height of the pressure chamber 1 and W is the width of the pressure chamber 1, as shown in FIG. ing. The height H of the pressure chamber 1 is the sum of the overall height in the height direction C of the partition wall 3 and the thickness D of the adhesive 16. The width W of the pressure chamber 1 is the width of the bottom electrode 18, and the width T of the partition wall 3 is a width between the signal electrode 14 and the signal electrode 15.

  As shown in FIG. 3, the extraction electrode 4 is individually formed on the other surface 12 b of the second substrate 12 corresponding to each pressure chamber 1. As shown in FIG. 1, the signal wiring 51 of the flexible substrate 50 is joined to the extraction electrode 4 formed on the second substrate 12. At this time, the extraction electrode 4 and the signal wiring 51 are aligned and joined.

  As shown by the arrows in FIG. 4, the partition wall portion 3 protrudes from one surface 12 a of the second substrate 12 and is polarized in a direction parallel to the height direction C, and a reverse direction to the base-side piezoelectric body 3 </ b> A. It has a chevron structure in which the tip-side piezoelectric body 3B polarized in the direction is joined by an adhesive 3C.

  Next, a method for applying a voltage to the electrodes 14 and 15 will be described. FIG. 5 is a partial perspective view showing a part of the discharge unit 10. 5A is a perspective view of the discharge unit 10 viewed from the front side, and FIG. 5B is a perspective view of the discharge unit 10 viewed from the back side. In FIG. 5, it is assumed that one pressure chamber 1 and two dummy chambers 2 are formed in the discharge unit 10.

As shown in FIG. 5A, a plurality of extraction electrodes 4 ₁ , 4 ₂ , 4 ₃ and a common electrode 22 are formed on the other surface 12b of the second substrate 12, and the flexible substrate 50 (FIG. 1). ) Signal wiring 51.

As shown in FIG. 5A, a front electrode 20 that is continuously connected to the signal electrode 14 and is electrically connected to the signal electrode 14 is formed in the front groove 7. There are connected so as to be electrically conductive to the extraction electrode 4 _2. Next, as shown in FIG. 5B, a back electrode 21 that is continuously connected to the signal electrode 15 and is electrically connected to the signal electrode 15 is formed, and this back electrode 21 is connected to the common electrode 22. Are connected to the extraction electrodes 4 ₁ and 4 _{3 so as} to be electrically conductive.

In the above electrode arrangement, when a voltage is applied to VA to the electrode 4 ₂ is taken out from the flexible substrate 50 (FIG. 1), the voltage VA is applied to the signal electrodes 14 via the front electrode 20. Similarly, as shown in FIG. 5 (b), the flexible substrate 50 by applying a voltage VB to one of the electrodes 4 ₁ and 4 ₃ removed from (FIG. 1), the voltage to the signal electrode 15 via the back electrode 21 VB is applied. In the present embodiment, the voltage VB is a ground potential.

  Next, the operation of the inkjet head 100 according to this embodiment will be described. FIG. 6 is a schematic diagram for explaining the displacement of the partition wall 3 and the deformation of the pressure chamber 1 when a voltage is applied to each electrode. Here, for the sake of explanation, it is assumed that the voltage VA is applied to the signal electrode 14, and similarly, the voltage VB is applied to the signal electrode 15.

  FIG. 6A shows a so-called ground state of the applied voltage VA = VB, and the partition 3 is not displaced in this state.

  Next, FIG. 6B shows how the partition wall 3 is displaced and the pressure chamber 1 is deformed when the applied voltage VA> VB. The voltages VA and VB are applied in a direction orthogonal to the polarization direction, and the partition wall portion 3 undergoes shear deformation. In this case, each partition wall 3 is displaced in a dogleg shape in a direction in which the cross-sectional area of the pressure chamber 1 is enlarged. By applying a voltage to each partition wall 3 in this way, the ink in the pressure chamber 1 can be filled.

  Next, FIG. 6C shows how the partition wall 3 is displaced and the pressure chamber 1 is deformed when the applied voltage VA <VB. In this case, each partition wall portion 3 is displaced in a U shape in a direction in which the cross-sectional area of the pressure chamber 1 is reduced. By applying a voltage to each partition wall 3 in this way, the ink inside the pressure chamber 1 can be pressurized and the ink can be ejected from the nozzle 30a (FIG. 1).

  FIG. 7 is a schematic view of a portion of the discharge unit 10 excluding the first substrate 11. FIG. 7A is a perspective view of a portion of the discharge unit 10 excluding the first substrate 11. 7B is a cross-sectional view taken along a plane parallel to the longitudinal direction A2 of the pressure chamber 1 in FIG. 7A, and FIG. 7C is a longitudinal direction of the dummy chamber 2 in FIG. 7A. It is sectional drawing which follows a surface parallel to A2. The height of each pressure chamber 1 is increased from the first end 1a on the nozzle side toward the second end 1b on the common liquid chamber side in the longitudinal direction A2. On the other hand, the height of each dummy chamber 2 decreases from the end portion 2a on the nozzle side toward the end portion 2b on the common liquid chamber side in the longitudinal direction A2, and communicates with the common liquid chamber 43 (FIG. 2). Not.

  FIG. 8 is a schematic diagram of the pressure chamber. FIG. 8A is a schematic diagram when the pressure chamber 1 and the dummy chamber 2 are overlapped when viewed from the width direction B. FIG. FIG. 8B is a perspective view of the pressure chamber 1.

  In each partition wall portion 3, each electrode pair 13 is divided into two, a movable region R 1 that applies an electric field to be sheared and deformed at the nozzle side portion, and a non-movable region R 2 that does not apply an electric field at the common liquid chamber side portion. Further, they are arranged on both side surfaces of each partition wall 3 so as to face each other with the movable region R1 interposed therebetween.

  In the present embodiment, conductors are formed on the entire side surface on the pressure chamber 1 side and on the entire side surface of the dummy chamber 2 on both side surfaces of the partition wall portion 3, but only the portions that overlap each other when viewed in the width direction B. , Electrodes 14 and 15.

  Here, when viewed from the width direction B, the first boundary point closest to the first end 1a on the boundary X between the movable region R1 and the non-movable region R2 is P1, and the second boundary 1b on the boundary X is closest to the second end 1b. Let P2 be the near second boundary point. The cross-sectional area of the cross section of the pressure chamber 1 along the plane perpendicular to the longitudinal direction A2 at the first boundary point P1 is S1, and the cross section of the pressure chamber 1 along the plane perpendicular to the longitudinal direction A2 at the second end 1b is The cross-sectional area is S2.

  Each pressure chamber 1 is formed so that the cross-sectional area S2 is larger than the cross-sectional area S1. In this embodiment, the width of the pressure chamber 1 is formed to have a constant length from the first end 1a to the second end 1b. Therefore, in the present embodiment, the height H2 of each pressure chamber 1 at the second end 1b is higher than the height H1 of each pressure chamber 1 at the first boundary point P1.

  More specifically, as shown in FIG. 8 (b), in the pressure chamber 1, the first end 1a on the nozzle side and the middle in the longitudinal direction A2 have a constant height H3 (a constant cross-sectional area). A pressure chamber flat portion 207 is formed. In the pressure chamber 1, the length in the longitudinal direction A 2 from the first end 1 a to the boundary point P 1 is longer than the length in the longitudinal direction A 2 of the pressure chamber flat portion 207. The height H1 of the pressure chamber 1 at the boundary point P1 is higher than the height H3 of the pressure chamber flat portion 207.

  At this time, when the cross-sectional area of the cross section along the plane perpendicular to the longitudinal direction A2 is S in the pressure chamber 1, the cross-sectional area S increases from the boundary point P1 toward the common liquid chamber 43 in the longitudinal direction A2. The cross-sectional area S2 of the surface in contact with the common liquid chamber 43 is the maximum area in the cross-sectional area S.

  In the present embodiment, each pressure chamber 1 is continuous as the cross-sectional area S of the cross section along the plane perpendicular to the longitudinal direction A2 of each pressure chamber 1 moves from the first boundary point P1 toward the second end 1b. It is formed to be wide. In addition, although the cross-sectional area S shall change continuously, you may form so that it may become large in steps.

  In the present embodiment, the total length L in the longitudinal direction A2 of the pressure chamber 1 is a length L1 from the first end 1a to the second boundary point P2, and a length from the second boundary point P2 to the second end 1b. It is the sum of L2 and is in the range of 6 [mm] to 14 [mm].

  The width T of the partition wall 3 (FIG. 4) is in the range of 30 [μm] to 100 [μm], and the width W of the pressure chamber 1 is in the range of 30 [μm] to 100 [μm]. is there.

  The height H1 of the pressure chamber 1 at the first boundary point P1 is in the range of 100 [μm] to 400 [μm], and the height H2 of the pressure chamber 1 on the surface in contact with the common liquid chamber 43 in the pressure chamber 1 is 400 [μm] to 1500 [μm].

  The operation of the inkjet head 100 of this embodiment will be described. FIG. 9 is a schematic diagram for explaining the operation of the inkjet head 100 when ink is ejected in the first embodiment.

  FIG. 9A is a cross-sectional view of the inkjet head 100, and shows a state where the drive voltage VA = VB (FIG. 6A). In the ground state, the ink in the pressure chamber 1 does not flow.

  9B, when VA> VB (FIG. 6B), in the movable region R1, the partition wall portion 3 undergoes shear deformation in a direction in which the cross-sectional area of the pressure chamber 1 is enlarged. As the ink in the nozzle 30a flows toward the pressure chamber 1 side, the meniscus 28 is drawn into the nozzle 30a, and at the same time, the ink flows from the common liquid chamber 43 toward the pressure chamber 1, so that the length of the pressure chamber 1 is increased. The ink pressure near the center in the direction A2 increases. At this time, since the cross-sectional area S2 is larger than the cross-sectional area S1 and the flow path resistance in the pressure chamber 1 is low, ink is efficiently supplied to the portion corresponding to the movable region R1 of the pressure chamber 1.

  9C, when VA <VB (FIG. 6C), the partition wall portion 3 is displaced in the direction of reducing the cross-sectional area of the pressure chamber 1 in the movable region R1. At this time, the pressure generated in the ink in the pressure chamber 1 becomes maximum, and the ink flows toward the nozzle 30a and the common liquid chamber 43 in the longitudinal direction A2.

  At this time, since the cross-sectional area S in the pressure chamber 1 increases from the boundary point P1 (FIG. 9A) toward the common liquid chamber 43 in the longitudinal direction A2, the ink flow toward the common liquid chamber 43 is increased. can do. That is, the flow passage resistance of the portion corresponding to the non-movable region R2 of the pressure chamber 1 is smaller than the flow passage resistance of the portion corresponding to the movable region R1 of the pressure chamber 1, and the second end 1b when the pressure chamber 1 is compressed. The ink can easily flow to the side. As a result, the flow of ink toward the nozzle 30a is reduced, and the rate of change in the ejection speed with respect to the pressure applied to the ink in the pressure chamber 1, that is, the voltage sensitivity can be reduced. Thereby, the controllability of the discharge speed of the droplets discharged from the nozzle 30a is improved.

  In addition, since the cross-sectional area S increases continuously (or stepwise) from the first boundary point P1 toward the second end 1b, the ink can flow more effectively. Therefore, the controllability of the discharge speed of the droplets discharged from the nozzle 30a is further improved.

  Thus, in order to reduce the voltage sensitivity, the ratio of the portion corresponding to the non-movable region R2 to the portion corresponding to the movable region R1 in the pressure chamber 1 is increased, and the flow of ink toward the common liquid chamber 43 is controlled. It is effective to do.

  On the other hand, in order to discharge a droplet from the nozzle 30a with a low voltage applied to the electrode pair 13, it is effective to increase the displacement volume per unit voltage in the movable region R1 and increase the pressure applied to the ink. is there.

  In view of these, in the pressure chamber 1, the cross-sectional area ratio between the cross-sectional area of the portion corresponding to the movable region R1 and the cross-sectional area of the portion corresponding to the non-movable region R2, and the length and non-limit of the portion corresponding to the movable region R1. It is preferable to adjust the ratio with the length of the portion corresponding to the movable region R2. By adjusting these ratios, it is possible to eject droplets from the nozzle 30a with a desired voltage sensitivity.

  Next, the manufacturing method of the inkjet head 100 in this embodiment is demonstrated. First, as shown in FIG. 10, the two piezoelectric plates 23 and 23 subjected to polarization treatment are reversed and bonded so that the polarization directions are opposite to each other, and then processed to a desired dimension by processing such as grinding. The piezoelectric substrate 24 is used.

  Subsequently, a plurality of partition walls 3 made of piezoelectric bodies (actuators) are formed on the piezoelectric substrate 24 by processing the partition grooves 25 as shown in FIG. Further, the front groove 7 is processed in the piezoelectric substrate 24. For the groove processing, it is preferable to use, for example, a cutting process with a diamond blade so that the piezoelectric substrate 24 does not become the Curie temperature or higher during the processing. However, since the front groove 7 is not a region that will later operate as an actuator, for example, laser processing or the like that does not consider the Curie temperature of the piezoelectric substrate 24 can be used.

  Next, as shown in FIG. 12, a conductive layer 26 is applied to the entire surface of the piezoelectric substrate 24 processed with the partition walls 25 including the inside of the partition grooves 25. This can be easily realized by electroless plating.

  Subsequently, as shown in FIG. 13, the conductive layer 26 on the upper surface (tip portion) 3a of the partition wall portion 3 is selectively removed by polishing or the like, and the groove portion 19 is formed so that the conductive layer 26 is further divided into the partition groove 25. Process. The groove 19 processed here may be formed by laser processing or cutting with a diamond blade.

  Next, as shown in FIG. 14, the adhesive 16 is applied to the tip 3 a of the partition wall 3 and bonded to the one surface 11 a of the first substrate 11 to obtain the discharge unit 10.

  The method of applying the adhesive 16 may be applied directly to the tip 3a of the partition wall 3 by means of screen printing, bar coater, or other means capable of adjusting the thickness, or once applied to a film or glass substrate and then transferred. You may do it. As the adhesive 16, for example, epoxy, phenol, or polyimide can be used.

  Thereafter, the front surface of the discharge unit 10 is ground and polished, and the conductive layer 26 is removed and adjusted to a desired size and shape. Further, the take-out electrode dividing grooves 27 are processed on the upper surface of the discharge unit 10 to obtain individual electrodes 4 that are electrically divided.

  After the discharge unit 10 is formed by the series of steps described above, the nozzle plate 30, the manifold 40, the flexible substrate 50, and the like are bonded together as shown in FIG. 1 to obtain the inkjet head 100 according to the present embodiment. .

[Second Embodiment]
Next, a liquid ejection apparatus according to a second embodiment of the present invention will be described. Also in this embodiment, the liquid ejection device is an inkjet head. FIG. 15 is a schematic diagram of a pressure chamber according to the second embodiment of the present invention. FIG. 15A is a schematic diagram when the pressure chamber and the dummy chamber are overlapped when viewed from the width direction. FIG. 15B is a perspective view of the pressure chamber.

  As in the first embodiment, as shown in FIG. 15A, in the partition wall portion 3 forming the pressure chamber 1, the portion sandwiched between the electrode pairs 13 undergoes shear deformation, so that the movable region R1 is designated as the movable region R1. The area other than is assumed to be a non-movable area R2. Similarly to the first embodiment, on the boundary between the movable region R1 and the non-movable region R2, the end point on the nozzle side in the longitudinal direction A2 is defined as the first boundary point P1, and the end point on the common liquid chamber side in the longitudinal direction A2 is defined as the first end point. Two boundary points P2.

  From FIG. 15 (b), when the area of the cross section of the pressure chamber 1 along the plane perpendicular to the longitudinal direction A2 is defined as the cross sectional area S, the cross sectional area S is from the boundary point P1 to the common liquid chamber side in the longitudinal direction A2. It becomes larger toward the second end 1b. The cross-sectional area S2 of the pressure chamber 1 on the surface in contact with the common liquid chamber is the maximum area in the cross-sectional area S.

  Further, in the pressure chamber 1, the cross-sectional area S is a flat portion in the longitudinal direction A2 from the first end 1a on the nozzle side to the second end 1b on the common liquid chamber side, and the movable region R1. The portion sandwiched between the movable regions is referred to as a movable region flat portion 206, and the entire flat portion is referred to as a pressure chamber flat portion 207. The length of the pressure chamber flat portion 207 in the longitudinal direction A2 is longer than the length of the movable region flat portion 206.

  When the cross-sectional area S1 and the cross-sectional area S2 of the pressure chamber 1 are compared, the cross-sectional area S2 is wider than the cross-sectional area S1. Specifically, the width W of the pressure chamber 1 is constant, and the height H2 of the pressure chamber 1 is higher than the height H1.

  The cross-sectional area S of the pressure chamber 1 is constant from the first boundary point P1 to the middle toward the second end 1b, and continuously increases from the middle toward the second end 1b. Yes.

  Even in the above configuration, the cross-sectional area S in the pressure chamber 1 increases from the boundary point P1 to the common liquid chamber 43 in the longitudinal direction A2 as in the first embodiment. The flow of ink heading can be increased. That is, the flow passage resistance of the portion corresponding to the non-movable region R2 of the pressure chamber 1 is smaller than the flow passage resistance of the portion corresponding to the movable region R1 of the pressure chamber 1, and the second end 1b when the pressure chamber 1 is compressed. The ink can easily flow to the side. As a result, the flow of ink toward the nozzle 30a is reduced when droplets are ejected, and the rate of change in ejection speed with respect to the pressure applied to the ink in the pressure chamber 1, that is, the voltage sensitivity can be reduced. Thereby, the controllability of the discharge speed of the droplets discharged from the nozzle 30a is improved.

[Third Embodiment]
Next, a liquid ejection apparatus according to a third embodiment of the present invention will be described. Also in this embodiment, the liquid ejection device is an inkjet head. FIG. 16 is a schematic view of a pressure chamber according to the third embodiment of the present invention. FIG. 16A is a schematic diagram when the pressure chamber and the dummy chamber are overlapped when viewed from the width direction. FIG. 16B is a perspective view of the pressure chamber.

  In the third embodiment, the movable region R1 of the partition wall 3 extends to a portion corresponding to a region where the height of the pressure chamber 1 is increased in the longitudinal direction A2 toward the common liquid chamber. More specifically, as shown in FIG. 16B, the length of the movable region flat portion 206 in the pressure chamber 1 is longer than that of the pressure chamber flat portion 207.

  At this time, the cross-sectional area S of the pressure chamber 1 increases from the first boundary point P1 toward the common liquid chamber in the longitudinal direction A2, and the cross-sectional area S2 of the pressure chamber 1 on the surface in contact with the common liquid chamber is the cross-sectional area. S is the maximum area.

  Even in the above configuration, the cross-sectional area S in the pressure chamber 1 increases from the boundary point P1 to the common liquid chamber 43 in the longitudinal direction A2 as in the first embodiment. The flow of ink heading can be increased. That is, the flow passage resistance of the portion corresponding to the non-movable region R2 of the pressure chamber 1 is smaller than the flow passage resistance of the portion corresponding to the movable region R1 of the pressure chamber 1, and the second end 1b when the pressure chamber 1 is compressed. The ink can easily flow to the side. As a result, the flow of ink toward the nozzle 30a is reduced when droplets are ejected, and the rate of change in ejection speed with respect to the pressure applied to the ink in the pressure chamber 1, that is, the voltage sensitivity can be reduced. Thereby, the controllability of the discharge speed of the droplets discharged from the nozzle 30a is improved.

[Fourth Embodiment]
Next, a liquid ejection apparatus according to a fourth embodiment of the present invention will be described. Also in this embodiment, the liquid ejection device is an inkjet head. FIG. 17 is a schematic view of a pressure chamber according to the fourth embodiment of the present invention. FIG. 17A is a schematic diagram when the pressure chamber and the dummy chamber are overlapped when viewed from the width direction. FIG. 17B is a perspective view of the pressure chamber.

  In the fourth embodiment, the height of the pressure chamber 1 gradually increases from the first end 1a on the nozzle side in the longitudinal direction A2 toward the first boundary point P1. As shown in FIG. 17B, the cross-sectional area S of the pressure chamber 1 increases from the first boundary point P1 toward the common liquid chamber in the longitudinal direction A2, and the pressure on the surface in contact with the common liquid chamber The cross-sectional area S2 of the chamber 1 is the maximum area in the cross-sectional area S.

  Even in the above configuration, the cross-sectional area S in the pressure chamber 1 increases from the boundary point P1 to the common liquid chamber 43 in the longitudinal direction A2 as in the first embodiment. The flow of ink heading can be increased. That is, the flow passage resistance of the portion corresponding to the non-movable region R2 of the pressure chamber 1 is smaller than the flow passage resistance of the portion corresponding to the movable region R1 of the pressure chamber 1, and the second end 1b when the pressure chamber 1 is compressed. The ink can easily flow to the side. As a result, the flow of ink toward the nozzle 30a is reduced when droplets are ejected, and the rate of change in ejection speed with respect to the pressure applied to the ink in the pressure chamber 1, that is, the voltage sensitivity can be reduced. Thereby, the controllability of the discharge speed of the droplets discharged from the nozzle 30a is improved.

  FIG. 18 is a schematic diagram showing a cross section of the discharge unit 10. FIG. 18A shows the structure of the discharge unit 10 according to this embodiment, and the length L of the pressure chamber 1 is 12 [mm].

  The length L in the longitudinal direction A2 of the pressure chamber 1 is 12 [mm], and the cross-sectional area S of the pressure chamber 1 increases from the first boundary point P1 toward the common liquid chamber 43 in the longitudinal direction A2. On the other hand, the sectional area S2 of the pressure chamber 1 in contact with the common liquid chamber 43 is larger than the sectional area S1 of the pressure chamber 1 at the first boundary point P1, and the sectional area S1 is the maximum sectional area in the pressure chamber 1. More specifically, the height H1 of the pressure chamber 1 at the first boundary point P1 is 240 [μm], the height H2 of the pressure chamber 1 on the surface in contact with the common liquid chamber 43 is 650 [μm], and the pressure chamber 1 The width W (see FIG. 8) is 60 [μm].

  The length L1 in the longitudinal direction A2 between the first end 1a (nozzle 30a) and the second boundary point P2 is 7.3 [mm], and the second boundary point P2 and the second end 1b (common liquid) The length L2 in the longitudinal direction A2 between the chamber 43) is 4.7 [mm].

  The cross-sectional area S is represented by the product of the height H of the pressure chamber 1 and the width W of the pressure chamber 1, and the ratio of the cross-sectional area S1 and the cross-sectional area S2 is R11 (= S1 / S2). The cross-sectional area ratio R11 is 2.7. When the ratio of the length L1 to the length L2 is R12 (= L2 / L1), the length ratio R12 is 0.64.

  FIG. 18B shows the structure of the discharge unit of Comparative Example 1, and the cross-sectional area S has a constant height and a constant width in the longitudinal direction A2. That is, the cross-sectional area is the same from the cross-sectional area S1 of the pressure chamber intersecting the first boundary point P1 to the cross-sectional area S2 of the pressure chamber in contact with the common liquid chamber.

  More specifically, the length L of the pressure chamber is 12 [mm] as in the embodiment. The length L1 is 11 [mm], the length L2 is 1 [mm], and the width W of the pressure chamber is 60 [μm].

  The height H1 of the pressure chamber at the first boundary point P1 is 240 [μm], and the height H2 of the pressure chamber on the surface in contact with the common liquid chamber is also 240 [μm]. The ratio R11 between the cross-sectional area S1 and the cross-sectional area S2 is 1.0. The ratio R12 between the length L1 and the length L2 is 0.09.

  FIG. 18C shows the structure of the discharge unit of Comparative Example 2, in which the length L of the pressure chamber is shortened to 8 [mm] compared to Comparative Example 1 (FIG. 18B). The height H1 of the pressure chamber at the first boundary point P1 is 240 [μm], the height H2 of the pressure chamber on the surface in contact with the common liquid chamber is 240 [μm], and the width W of the pressure chamber is 60 [μm].

  Moreover, the length L1 is 7.3 [mm] like the embodiment. The length L2 is 0.7 [mm]. The ratio R11 between the cross-sectional area S1 and the cross-sectional area S2 is 1.0. The ratio R12 between the length L1 and the length L2 is 0.09.

  In addition, in the example (FIG. 18A), the comparative example 1 (FIG. 18B), and the comparative example 2 (FIG. 18C), the partition wall width T is 70 [μm] and the nozzle diameter is 10. [Μm].

  FIG. 19 is a graph showing the relationship between the applied voltage and the droplet discharge speed in the inkjet heads of the example, comparative example 1 and comparative example 2. The results of comparing these characteristics are shown in Table 1.

  The voltage sensitivity of Comparative Example 1 is as high as 2.0 [m / s / V], whereas the voltage sensitivity of Comparative Example 2 in which the total length L of the pressure chamber is shorter than that of Comparative Example 1 is 1.4 [m / s / V]. m / s / V], and the voltage sensitivity can be reduced as compared with Comparative Example 1. However, in Comparative Example 2, the threshold voltage for discharging droplets is higher than that in Comparative Example 1. On the other hand, in this embodiment, the voltage sensitivity can be lowered as compared with Comparative Examples 1 and 2 without increasing the threshold value of the voltage for discharging with respect to Comparative Example 1.

  FIG. 20 is a graph showing the relationship between the nozzle diameter and the voltage sensitivity in the inkjet heads of the example, comparative example 1, and comparative example 2.

  It can be seen that the voltage sensitivity increases as the nozzle diameter decreases. In order to obtain a desired voltage sensitivity of 0.5 [V / m / s] to 1.0 [V / m / s], in Comparative Example 1, the nozzle diameter needs to be at least 30 [μm]. In Comparative Example 2, it can be seen that the nozzle diameter needs to be at least 20 [μm]. On the other hand, it can be seen that this embodiment is effective when the diameter of the nozzle is in the range of 5 [μm] to 15 [μm].

  FIG. 21 is a schematic diagram showing a pressure chamber of the ink jet head in the present embodiment. FIG. 21A is a cross-sectional view of the pressure chamber of the inkjet head, and FIG. 21B is a perspective view of the pressure chamber of the inkjet head. In the configuration of FIG. 21, by changing the height H2 of the pressure chamber 1 on the surface in contact with the common liquid chamber 43 to a range of 250 [μm] to 650 [μm], the cross-sectional area S1 of the pressure chamber 1 and the pressure chamber 1 The ratio R11 = S2 / S1 of the cross-sectional area S2 was changed and evaluated.

  In addition, the length L of the pressure chamber 1 is 12 [mm], the length L1 in the longitudinal direction A2 from the nozzle 30a to the second boundary point P2 is 7.3 [mm], and the common liquid chamber 43 from the second boundary point P2 The length L2 in the longitudinal direction A2 was set to 4.7 [mm]. The height H1 of the pressure chamber 1 is 240 [μm], the width W of the pressure chamber 1 is 60 [μm], and the width T of the partition wall is 70 [μm].

  FIG. 22 is a graph showing the relationship between the cross-sectional area ratio R11 of the pressure chamber 1 and the voltage sensitivity. The voltage sensitivity can be lowered by increasing the cross-sectional area ratio R11 of the pressure chamber 1.

  In order to obtain a desired voltage sensitivity of 0.5 [V / m / s] to 1.0 [V / m / s], the cross-sectional area ratio R11 of the pressure chamber 1 is in the range of 1.8 to 3.5. It turns out that it is good to do.

  FIG. 23 is a graph showing the relationship between the length ratio R12 and the voltage sensitivity. The length L of the pressure chamber 1 is constant at 12 [mm], and the length L1 from the nozzle 30a to the second boundary point P2 is in the range of 4 [mm] to 10 [mm], so that the pressure chamber 1 The length ratio R12 in the range was set in the range of 0.6 to 1.7, and the relationship with the voltage sensitivity was evaluated. In addition, the height H1 of the pressure chamber 1 at the first boundary point P1 is 250 [μm], the height H2 of the pressure chamber 1 on the surface in contact with the common liquid chamber 43 is 400 [μm], and the width W of the pressure chamber 1 is 60 [Μm], and the partition wall width T was set to 70 [μm].

  From FIG. 23, the voltage sensitivity can be lowered by increasing the ratio R12 of the length of the movable region and the non-movable region in the pressure chamber 1. It can be seen that R12 should be in the range of 0.6 to 1.7 in order to achieve the desired voltage sensitivity of 0.5 to 1.0 [V / m / s].

  In other words, if the entire partition wall 3 forming the pressure chamber 1 is a movable region, the voltage sensitivity is too low. In contrast to this, the partition wall 3 is divided into two parts, a movable region to which an electric field for shear deformation is applied at the nozzle side portion and a non-movable region to which an electric field is not applied at the common liquid chamber side portion, thereby ensuring proper voltage sensitivity. Can be set to any value. And it can set to more appropriate voltage sensitivity by making ratio R12 into the range of 0.6-1.7.

  The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

  In the above embodiment, the ink jet head used in a printer or the like has been described as the liquid discharge head, but the present invention is not limited to this. For example, it may be a head that discharges a liquid containing metal fine particles used when forming metal wiring as the liquid, or may be a resist ink used for resist patterning.

  In the above embodiment, the partition wall is a piezoelectric body configured by joining a base end piezoelectric body polarized in the height direction and a front end piezoelectric body polarized in a direction opposite to the base end piezoelectric body. Although the case has been described, it may be composed of a piezoelectric body polarized in one direction in the height direction.

DESCRIPTION OF SYMBOLS 1 ... Pressure chamber, 1a ... 1st edge part, 1b ... 2nd edge part, 3 ... Partition part, 11 ... 1st board | substrate, 12 ... 2nd board | substrate, 13 ... Electrode pair, 30 ... Nozzle plate (nozzle member), 30a ... Nozzle, 40 ... Manifold (common liquid chamber forming member), 43 ... Common liquid chamber, 100 ... Inkjet head (liquid ejection device), P1 ... First boundary point, P2 ... Second boundary point, R1 ... Movable region, R2 ... Non-movable area

Claims (10)

A first substrate and a second substrate facing each other;
The first substrate and the second substrate are arranged in parallel with a gap in the width direction orthogonal to the height direction, and are formed of a piezoelectric body that forms a plurality of pressure chambers extending in the longitudinal direction. A plurality of partition walls,
A nozzle member which is disposed on the first end portion side in the longitudinal direction of each pressure chamber and in which each nozzle connected to each pressure chamber is formed;
A common liquid chamber forming member disposed on the second end opposite to the first end in the longitudinal direction of each pressure chamber and forming a common liquid chamber connected to the plurality of pressure chambers;
Both side surfaces of each partition wall so as to divide each partition wall into a movable region to which an electric field for shear deformation is applied at the nozzle side portion and a non-movable region to which the electric field is not applied at a common liquid chamber side portion. A plurality of electrode pairs arranged opposite to each other with the movable region interposed therebetween,
Each of the pressure chambers has a cross-sectional area of a cross section along a plane perpendicular to the longitudinal direction at the second end portion that is closest to the first end portion on the boundary between the movable region and the non-movable region. A liquid ejecting apparatus, wherein the liquid ejecting apparatus is formed so as to be wider than a cross-sectional area of a cross section along a plane perpendicular to the longitudinal direction at a boundary point.   2. The liquid ejection apparatus according to claim 1, wherein a height of each pressure chamber at the second end is higher than a height of each pressure chamber at the first boundary point.   In each of the pressure chambers, a cross-sectional area of a cross section along a plane perpendicular to the longitudinal direction of each of the pressure chambers becomes wider continuously or stepwise from the first boundary point toward the second end portion. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is formed as described above.   2. An air chamber that is disconnected from the common liquid chamber and is partitioned by the partition walls is formed between two adjacent pressure chambers of the plurality of pressure chambers. 4. The liquid ejection device according to any one of items 1 to 3.   5. The liquid ejection apparatus according to claim 1, wherein a diameter of the nozzle is in a range of 5 [μm] to 15 [μm].   2. S2 / S1 is in a range of 1.8 to 3.5, where S1 is a cross-sectional area at the first boundary point and S2 is a cross-sectional area at the second end portion. 6. The liquid ejection device according to any one of items 1 to 5.   The length in the longitudinal direction from the second boundary point closest to the second end on the boundary between the movable region and the non-movable region to the first end is L1, and from the second boundary point to the The length of the said longitudinal direction to a 2nd edge part is set to L2 / L1 in the range of 0.6-1.7, when L2 is set to the length in any one of Claim 1 thru | or 6 characterized by the above-mentioned. The liquid discharge apparatus as described. A method for manufacturing a liquid ejection device according to any one of claims 1 to 7 ,
Forming a plurality of partition walls in the piezoelectric substrate by processing a plurality of partition grooves, the depth of which increases from the middle toward the second end of the piezoelectric substrate;
Processing a front groove on the first end side of the plurality of partition walls;
Forming a conductive layer in the partition groove and the front groove;
A method for manufacturing a liquid ejection apparatus, comprising:   A method of manufacturing a metal wiring, wherein the metal wiring is formed using the liquid ejection device according to claim 1.   A method for producing a color filter, comprising producing a color filter using the liquid ejection device according to claim 1.

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