JP2009051077A - Liquid discharge head and liquid discharge apparatus - Google Patents

Abstract

Discharge performance is greatly improved by improving the rigidity of a member that forms a pressure chamber 11 and enabling high pressure to be applied to liquid in the pressure chamber while preventing an increase in flow resistance of a nozzle 12. The liquid discharge head 7 and the liquid discharge apparatus A are provided.
A liquid discharge head (head main body 91) converts a pressure chamber wall member 14 for defining and forming a pressure chamber 11 in which the liquid is stored, and a liquid in the pressure chamber 11 by being expanded and contracted in a predetermined direction. An actuator 19 for applying pressure is provided. The pressure chamber 11 is partitioned by an opposing partition wall that faces the expansion / contraction direction of the actuator 19 and a non-opposing partition wall that does not face the pressure chamber 11, and the nozzle 12 is provided in the pressure chamber wall member 14 at the non-opposing partition wall. And extending in a direction different from the expansion and contraction direction.
[Selection] Figure 2

Description

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

  Ink jet technology for ejecting ink droplets onto recording paper has been used in manufacturing processes in various fields including the electronics field in recent years. That is, by discharging a liquid material from a liquid discharge head, patterns are formed and uniform thin films are formed in various device manufacturing processes. Liquid discharge heads used for such pattern formation are required to discharge further small droplets and high-viscosity liquids. In order to realize a head having a high discharge capacity that satisfies these requirements, it is necessary to apply a higher pressure to the liquid in the pressure chamber.

For example, a liquid discharge head disclosed in Patent Document 1 includes a pressure chamber wall member that partitions and forms a pressure chamber in which liquid is stored, an elastic partition that partitions a part of the pressure chamber, and an elastic partition that expands and contracts. The actuator is driven to extend and contract so as to be deformed, and the actuator is stacked in this order in the extending / contracting direction. In this liquid discharge head, a nozzle extending in the expansion / contraction direction is provided on the side opposite to the actuator across the pressure chamber, and when pressure is applied to the liquid in the pressure chamber by elastic deformation of the elastic partition portion, Liquid is ejected in a telescopic direction through the nozzle. In the liquid discharge head having this configuration, the energy generated by driving the actuator can be efficiently converted into the pressure applied to the liquid in the pressure chamber, and a high pressure can be applied to the liquid.
Japanese Patent No. 2721127

  However, in the configuration of the liquid discharge head of the above-mentioned patent document, the partition wall (opposite partition wall) facing the expansion / contraction direction among the members partitioning the pressure chamber, particularly the partition wall partitioning the pressure chamber, is driven by the actuator. Therefore, a high pressure is applied to the facing compartment. Here, when the rigidity of the portion constituting the opposing partition wall is low, even when a high pressure is applied to the liquid in the pressure chamber, the portion is deformed. As a result, the pressure applied to the pressure chamber escapes, and as a result, the pressure applied to the liquid decreases.

  One way to increase the rigidity of the member is to increase the thickness. In the liquid discharge head, the thickness of the constituent part of the opposing partition wall may be increased. However, since the nozzles are formed in the constituent parts of the opposed partition walls so as to extend in the expansion and contraction direction as described above, the length of the nozzles is increased by increasing the thickness of this part. This leads to an increase in the flow path resistance of the nozzle. Therefore, by increasing the thickness of the constituent part of the opposing partition wall, the rigidity can be improved and a high pressure can be applied to the liquid in the pressure chamber. It becomes impossible to discharge a highly viscous liquid with small droplets.

  The present invention has been made in view of such a point, and an object of the present invention is to improve the rigidity of a member that forms a pressure chamber and to apply a high pressure to the liquid in the pressure chamber, while An object of the present invention is to provide a liquid discharge head and a liquid discharge apparatus in which discharge capability is greatly improved by preventing an increase in flow path resistance.

  According to one aspect of the present invention, the liquid discharge head is bonded to the pressure chamber wall member that defines the pressure chamber in which the liquid is stored, and the pressure chamber member via the elastic member, and is a part of the pressure chamber. And the elastic member is elastically deformed in the expansion / contraction direction via the pressure member, thereby applying pressure to the liquid in the pressure chamber. An actuator to be applied, and the pressure chamber is partitioned by at least a facing partition wall facing the stretching direction and a non-facing partition wall not facing the stretching direction, and the pressure chamber wall member includes A nozzle that discharges the liquid in the pressure chamber in accordance with the expansion and contraction drive is formed to communicate with the pressure chamber in the non-opposing partition wall and to extend in a direction different from the expansion and contraction direction.

  According to this configuration, the nozzle formed on the pressure chamber wall member communicates with the pressure chamber on the non-opposing partition wall and extends in a direction different from the expansion / contraction direction of the actuator. Since the nozzle is not formed in the portion constituting the opposing partition wall in the pressure chamber wall member, the thickness of this portion can be made relatively thick. On the other hand, the thickness of the part which comprises the non-opposing partition wall in which a nozzle is formed can be made relatively thin. Therefore, the length of the nozzle becomes relatively short, and an increase in flow path resistance is suppressed. Therefore, in the liquid discharge head described above, in the head configured to relatively increase the thickness of the portion constituting the opposing partition wall and elastically deform the elastic member via the pressure member by the expansion and contraction drive of the actuator, The discharge capacity of the head can be increased by making it possible to apply a high pressure to the liquid while suppressing the increase in flow path resistance by relatively shortening the nozzle length. That is, it becomes possible to discharge a relatively high-viscosity liquid with small droplets.

  The nozzle may be formed to extend in a direction substantially orthogonal to the expansion / contraction direction. By doing so, since the nozzle length becomes the shortest, the flow resistance is minimized and the discharge capability of the liquid discharge head can be further improved. Note that “substantially orthogonal” is not only orthogonal (90 °) but also a concept including a predetermined range including orthogonal, and includes, for example, about ± 30 ° with respect to 90 °.

  The pressure chamber wall member is formed with a pressure chamber recess defining the pressure chamber so as to open on a surface on the side joined to the pressure member, and the pressure chamber wall member has an opening of the pressure chamber recess. The portion constituting the opposed partition wall on the side opposite to the side may be thicker than the thickness of the portion constituting the non-opposed partition wall where the nozzle is formed.

  By doing so, sufficient rigidity is secured as the rigidity of the constituent part of the opposing partition wall in the pressure chamber wall member, and higher pressure can be applied to the liquid in the pressure chamber. On the other hand, the thickness of the constituent part of the non-opposing partition wall in the pressure chamber wall member is reduced, and the flow path resistance of the nozzle is further reduced.

  The actuator may be configured such that an area of a cross section orthogonal to the expansion and contraction direction is larger than a cross sectional area of the pressure chamber.

  When the actuator attached to the liquid discharge head is an actuator having a relatively large cross-sectional area, the actuator has a capability of applying a high pressure to the liquid in the pressure chamber. In this configuration, since the rigidity of the portion constituting the opposing partition wall is sufficiently ensured, it is possible to fully exert the capacity of the actuator and apply a high pressure to the liquid in the pressure chamber.

  The pressure chamber wall member may be made of a material having a Young's modulus of 0.1 to 10 GPa.

  In the liquid discharge head having this configuration, the rigidity of the constituent portion of the opposing partition wall is not ensured by the property of the material constituting the pressure chamber wall member (that is, a high-rigidity material is used), but the rigidity is used for the pressure chamber wall. This is ensured by the thickness of the constituent part of the opposing partition wall in the member. For this reason, the freedom degree of selection of the material which comprises a pressure chamber wall member improves. As a material for the pressure chamber wall member, for example, a resin material can be used. In such a case, it is advantageous in terms of reduction in manufacturing cost and corrosion resistance to the liquid filled in the pressure chamber.

  According to another aspect of the present invention, a liquid ejection apparatus includes the liquid ejection head. For this reason, since the improvement in the rigidity of the pressure chamber wall member and the reduction in the flow resistance of the nozzle are combined, the discharge capability of the liquid discharge head is improved, thereby realizing a liquid discharge device with a high discharge capability.

  As described above, according to the present invention, the nozzle formed in the pressure chamber wall member communicates with the pressure chamber in the non-opposing partition wall and extends in a direction different from the expansion / contraction direction, thereby forming the facing partition. The wall constituting the wall can be thickened to ensure rigidity and the nozzle length can be made relatively short to prevent an increase in flow path resistance. As a result, the liquid discharge head and the liquid discharge device The discharge capacity can be increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a schematic configuration of the liquid ejection apparatus A. The liquid ejection apparatus A includes a liquid ejection head 7 including one or a plurality of head bodies (see FIG. 2 and the like), and a stage 31 that supports the recording material 4.

  The liquid discharge head 7 is reciprocated in the main scanning direction (X direction shown in FIG. 1) by the head moving device 2 supported on the apparatus base 6, and the stage 31 is also moved on the stage supported on the apparatus base 6. The apparatus 3 reciprocates in the sub-scanning direction (Y direction shown in FIG. 1).

  The head moving device 2 includes a carriage 7 a that supports the liquid ejection head 7. The carriage 7a is guided by a carriage shaft 7b extending in the main scanning direction, and reciprocates in the main scanning direction by a driving source (for example, a motor) (not shown).

  The stage moving device 3 includes two stage shafts 32 and 32 that are arranged at a predetermined interval in the main scanning direction and extend in the sub scanning direction, respectively. The stage 31 is guided by these stage shafts 32 and 32 and reciprocates in the sub-scanning direction by a driving source (for example, a motor) (not shown).

  With this configuration, the liquid ejection apparatus A ejects a liquid material from the liquid ejection head 7 (head body) toward the recording material 4 while relatively moving the liquid ejection head 7 and the recording material 4 on the stage 31. Then, a desired pattern or a uniform thin film is formed on the recording material 4.

  As shown in FIGS. 2 and 3, the head main body 91 includes a pressure chamber 11 in which a liquid material is accommodated, and a nozzle 12 communicating with the pressure chamber 11. The head body 91 includes a pressure chamber wall member 14 that partitions the side surface and the bottom surface of the pressure chamber 11, a pressure member 15 that partitions the top surface of the pressure chamber 11, a holding member 16 that holds the pressure member 15, and an actuator 19. It has a laminated structure. In the following, the vertical direction in FIG. 2 is referred to as the vertical direction in the head main body 91, and the horizontal direction in FIG.

  The pressure chamber wall member 14 is a plate-like member made of, for example, a resin material having a thickness of about 2.0 mm, and a pressure chamber recess 14a is formed in the upper surface thereof. The pressure chamber recess 14a is a recess that divides a side surface and a bottom surface of the pressure chamber 11 by an inner peripheral surface and a bottom surface thereof. In the present embodiment, the width is set to about 0.3 mm, the length is set to about 1.0 mm, and the depth is set to about 0.25 mm. Here, the side surface of the pressure chamber 11 constituted by the inner peripheral surface of the pressure chamber recess 14a corresponds to a non-opposing partition wall that does not oppose the expansion / contraction direction of the actuator 19, as will be described later, and the bottom surface of the pressure chamber recess 14a. The bottom surface of the pressure chamber 11 constituted by the structure corresponds to the opposing partition wall that faces the expansion / contraction direction of the actuator 19. Thus, in the pressure chamber wall member 14, the portion constituting the opposing partition wall on the side opposite to the opening side of the pressure chamber recess 14a is made relatively thick (see t in FIG. 2). The portions constituting the non-opposing partition walls on both sides in the horizontal direction across the pressure chamber 11 are relatively thin.

  The pressure chamber wall member 14 is also formed with a supply port 14b that extends in the horizontal direction from one side surface and communicates with the inner peripheral surface of the pressure chamber recess 14a. The supply port 14 b is a hole for supplying the liquid material from the liquid material supply source (not shown) into the pressure chamber 11.

  The nozzle 12 is formed in the pressure chamber wall member 14 so as to extend in the horizontal direction from the other side surface and communicate with the inner circumferential surface of the pressure chamber recess 14a. The nozzle 12 includes a straight portion 12a having a substantially constant diameter, and a tapered portion 12b that is continuous with the straight portion 12a and decreases in diameter toward the tip. Here, the diameter of the straight portion 12a may be about φ0.15 mm, and the diameter of the tip opening of the tapered portion 12b may be about φ0.03 mm.

  In the pressure chamber wall member 14, it is preferable to form a water repellent film on the side surface where the tip opening of the nozzle 12 is formed from the viewpoint of the discharge stability of the liquid material. Such a water-repellent film can be formed by a known method.

  The holding member 16 is a plate-like member having a thickness of about 0.3 mm, for example, and is bonded to the upper surface of the pressure chamber wall member 14 via an adhesive layer 18a. The holding member 16 is also formed with a through hole 16a having a predetermined cross-sectional shape and penetrating in the thickness direction. The through hole 16a is a hole into which the pressure member 15 is inserted. As shown in FIG. 3, the center position of the pressure chamber recess 14 a of the pressure chamber wall member 14 and the center position of the through hole 16 a of the holding member 16 in a state where the holding member 16 is bonded to the upper surface of the pressure chamber wall member 14. Are set at the same position.

  The upper surface of the holding member 16 is fixed to other components of the head main body 91 (not shown in FIG. 2), so that the holding member 16 is not displaced even when the actuator 19 is driven. Yes.

  Between the holding member 16 and the pressure chamber wall member 14, an elastic member 18 that partitions the upper end portion of the side surface of the pressure chamber 11 is interposed. As will be described later, the elastic member 18 is a member for changing the volume of the pressure chamber 11 by elastically expanding and contracting when the pressure member 15 is displaced in the vertical direction as the actuator 19 is driven. As shown in FIG. 3, it is formed in a substantially rectangular annular shape. For example, the elastic member 18 may have a width of about 0.7 mm and a length of about 1.4 mm. The thickness may be about 0.02 mm to 0.1 mm, preferably about 0.03 mm. The elastic member 18 may be formed of, for example, a solvent-resistant rubber, specifically, fluorine rubber, silicon rubber, or the like in consideration of corrosion resistance against the liquid material.

  An adhesive layer 18 a that joins the holding member 16 and the pressure chamber wall member 14 to each other surrounds the outer peripheral surface of the elastic member 18. As a result, the adhesive layer 18 a is configured to restrict the elastic member 18 from being deformed by escaping toward the outside of the pressure chamber 11 when the elastic member 18 is elastically deformed.

  The pressure member 15 is a plate-like member made of a relatively high rigidity material such as stainless steel or ceramic. For example, the width may be about 0.5 mm, and the length may be about 1.2 mm. The pressure member 15 is in contact with the upper surface of the elastic member 18 by being inserted and held in the through hole 16 a of the holding member 16, and the upper surface of the pressure chamber 11 is formed by the lower surface of the pressure member 15. Partitioned. The pressurizing member 15 is held by the holding member 16 so as to be displaceable in the vertical direction, and is displaced in the vertical direction as the actuator 19 is driven, so that the elastic member 18 is expanded and contracted in the vertical direction.

  A gap between the pressure member 15 and the through hole of the holding member 16 is filled with a filler 16b. The filler 16b is elastically deformed so that the pressure member 15 can be displaced in the stacking direction. The filler 16b can be omitted.

  The actuator 19 is made of a laminated piezoelectric material having a width of about 0.5 mm, a length of about 1.1 mm, and a thickness of about 1.0 mm, for example. The lower end of the actuator 19 is joined to the upper surface of the pressure member 15, and the upper end of the actuator 19 is fixed to another constituent member not shown. The actuator 19 expands and contracts in the vertical direction in FIG. 2 when a voltage is applied to an electrode (not shown in FIG. 2) (see the white arrow in FIG. 2). With the expansion / contraction drive of the actuator 19, the pressure member 15 is displaced in the vertical direction in FIG. 2, and the elastic member 18 is expanded and contracted in the vertical direction accordingly, whereby the volume of the pressure chamber 11 is increased or decreased. . Here, as shown in FIG. 3, the actuator 19 has a cross-sectional area larger than the cross-sectional area of the pressure chamber 11, and the actuator 19 has a relatively high pressure relative to the liquid in the pressure chamber 11. Has the ability to apply.

  Next, the operation of the head main body 91 having the above configuration will be described. A predetermined voltage is applied to the actuator 19 in a state where the supply port 14b, the pressure chamber 11, and the nozzle 12 are filled with the liquid material. As a result, the actuator 19 is extended and deformed.

  The pressurizing member 15 is displaced downward as the actuator 19 expands and deforms, so that the elastic member 18 contracts and deforms, and pressure is applied to the liquid material in the pressure chamber 11. Then, the liquid material is pushed out from the nozzle 12 and is discharged as droplets in the horizontal direction in FIG. The droplets adhere to the recording material 4 in the form of dots.

  By canceling the voltage application to the actuator 19, the actuator 19 that has been extended returns to its original state, the pressurizing member 15 is displaced upward, and the volume of the pressure chamber 11 returns to its original state. At this time, the liquid material is replenished into the pressure chamber 11 from the supply source of the liquid material through the supply port 14b.

  In the head main body 91, the thickness of the portion constituting the bottom surface (opposing partition wall) of the pressure chamber 11 in the pressure chamber wall member 14 is relatively thick, thereby ensuring sufficient rigidity. Therefore, even when the actuator 19 is driven to expand and contract in the vertical direction and pressure is applied to the liquid in the pressure chamber 11 in the vertical direction, deformation or the like does not occur in this portion. As a result, for example, a high voltage (for example, 20 V) can be applied to the actuator 19 to apply a high pressure to the liquid material in the pressure chamber 11.

  The nozzle 12 formed on the pressure chamber wall member 14 extends in the horizontal direction perpendicular to the expansion / contraction direction of the actuator 19 and communicates with the side surface (non-opposing partition wall) of the pressure chamber 11. For this reason, for example, as shown by an imaginary line in FIG. 2, the length of the nozzle is significantly shortened compared to the case where the nozzle is formed in the portion constituting the bottom surface of the pressure chamber 11 so as to extend in the expansion / contraction direction of the actuator 19. can do. As a result, the flow path resistance of the nozzle 12 can be made as small as possible.

  Therefore, the discharge capacity of the head main body 91 is increased, and small droplet discharge and high viscosity liquid discharge are realized. The head main body 91 having the above-described configuration can discharge a high-viscosity liquid having a viscosity of, for example, 50 cP (0.05 Pa · s) with a small droplet amount of about 20 pl (picoliter).

  Here, the actuator 19 is not driven by the so-called push-pull drive as described above, but after the pressurizing member 15 is displaced upward to fill the pressure chamber 11 with the liquid material, the pressurizing member 15 is moved. It is good also as what is called pulling drive which discharges a liquid material from the nozzle 12 by returning to the original.

  The configuration of the head body in the liquid discharge head 7 is not limited to the above configuration. For example, a configuration as shown in FIG. 4 may be adopted.

  That is, the head main body 92 is configured by laminating the pressure chamber wall member 14, the pressure member 17, and the actuator 19 in this order.

  In the head main body 92, a thin film 20 is interposed between the pressure chamber wall member 14 and the pressure member 17, and the upper surface of the pressure chamber 11 is partitioned by the thin film 20. The thin film 20 may be, for example, a resin film having a thickness of 0.01 to 0.2 mm or a metal thin film having a thickness of 0.05 to 0.5 mm. Such a configuration in which the thin film 20 is interposed is an advantageous configuration for improving the corrosion resistance to the liquid material in the pressure chamber 11.

  The pressure member 17 is a substantially plate-like member, and a convex portion 17a protruding downward is formed at a position corresponding to the opening of the pressure chamber concave portion 14a on the lower surface thereof.

  An elastic member 21 is disposed between the pressure member 17 and the thin film 20 in a range excluding the convex portion 17a of the pressure member 17. The elastic member 21 is a member that allows displacement of the pressing member 17 in the vertical direction by elastically expanding and contracting in the vertical direction.

  Thus, the actuator 19 is joined to the upper surface of the pressure member 17, and the head main body 92 is configured such that when the actuator 19 is driven, the elastic member 21 elastically expands and contracts when the actuator 19 is driven. Accordingly, the pressure member 15 is displaced in the vertical direction, and the volume of the pressure chamber 11 is changed.

  Also in the head main body 92 having this configuration, the thickness of the portion constituting the bottom surface (opposing partition wall) of the pressure chamber 11 is relatively thick and sufficient rigidity is ensured. It becomes possible to apply a high pressure to the liquid material inside. Further, the nozzle 12 formed on the pressure chamber wall member 14 extends horizontally perpendicular to the expansion / contraction direction of the actuator 19 and communicates with the side surface (non-opposing partition wall) of the pressure chamber 11. Thus, the flow path resistance of the nozzle 12 can be made as small as possible.

  As a result, the discharge capacity of the head main body 92 is increased, and small droplet discharge and high viscosity liquid discharge are realized.

  The nozzle 12 is not limited to be formed to extend in the horizontal direction, and the angle thereof may be adjusted as appropriate according to the configuration of the liquid ejection apparatus A, for example.

  Further, the material of the pressure chamber wall member 14 is not limited to the resin material, and for example, a metal material such as stainless steel or other materials can be used.

  Furthermore, the actuator for applying pressure to the liquid in the pressure chamber 11 is not limited to a piezoelectric body, and for example, a magnetostrictive element can be employed.

  As described above, since the present invention realizes the ejection of small droplets and the ejection of high-viscosity liquids, for example, the electronics field such as the manufacture of various devices such as flat panel displays and circuit boards, the optoelectronics field, In various technical fields such as the bio-medical field, it is useful as a liquid material ejection head and liquid material ejection device for forming various patterns, uniform thin films, etc., and by ejecting ink, for example, a recording medium such as recording paper It is also useful as an ink discharge head and an image forming apparatus for forming an image thereon.

It is a schematic perspective view which shows the liquid discharge apparatus which concerns on embodiment. It is a longitudinal cross-sectional view which shows the head main body which concerns on embodiment. It is a top view of the head body. It is a longitudinal cross-sectional view which shows the head main body which concerns on other embodiment.

Explanation of symbols

11 Pressure chamber 12 Nozzle 14 Pressure chamber wall member 14a Pressure chamber recess 19 Actuator 7 Liquid ejection head 91 Head body 92 Head body A Liquid ejection device

Claims (6)

A pressure chamber wall member that defines and forms a pressure chamber in which a liquid is stored;
A pressure member joined to the pressure chamber member via an elastic member to form a part of the pressure chamber; and
An actuator that elastically deforms the elastic member in the expansion / contraction direction via the pressure member by driving the expansion / contraction in a predetermined expansion / contraction direction, thereby applying pressure to the liquid in the pressure chamber;
The pressure chamber is partitioned by at least a facing partition wall facing the stretching direction and a non-facing partition wall not facing the stretching direction,
In the pressure chamber wall member, a nozzle that discharges the liquid in the pressure chamber with the expansion / contraction drive of the actuator communicates with the pressure chamber in the non-opposing partition wall and extends in a direction different from the expansion / contraction direction. A liquid discharge head that is formed. The liquid discharge head according to claim 1,
The liquid ejection head, wherein the nozzle extends in a direction substantially orthogonal to the expansion / contraction direction. The liquid discharge head according to claim 1 or 2,
The pressure chamber wall member is formed with a pressure chamber recess for partitioning the pressure chamber, which is open to a surface on the joint side with the pressure member,
In the pressure chamber wall member, the portion constituting the opposing partition wall on the side opposite to the opening side of the pressure chamber recess is compared with the thickness of the portion constituting the non-opposing partition wall where the nozzle is formed. Liquid discharge head is thickened. The liquid discharge head according to any one of claims 1 to 3,
The actuator is a liquid discharge head in which an area of a cross section perpendicular to the expansion / contraction direction is configured to be larger than a cross-sectional area of the pressure chamber. In the liquid discharge head according to any one of claims 1 to 4,
The pressure chamber wall member is a liquid discharge head made of a material having a Young's modulus of 0.1 to 10 GPa.   A liquid discharge apparatus comprising the liquid discharge head according to claim 1.

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