Liquid discharge head and printing device

Abstract

To provide a liquid discharge head that suppress a discharge failure due to crosstalk and can reduce a droplet size of liquid to be discharged, and a printing device.SOLUTION: A liquid discharge head includes: a pressure chamber connected to a nozzle for discharging liquid; a common flow channel for supplying the liquid to the pressure chamber; and an intermediate chamber disposed between the pressure chamber and the common flow channel and connected respectively to the pressure chamber and the common flow channel via a throttle flow channel. The intermediate chamber has a capacity that is larger than a capacity of the pressure chamber.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head that ejects a liquid such as ink for printing and a printing apparatus having the liquid ejection head.

Background Art

[0002] There is known a drop-on-demand type inkjet head that ejects an amount of ink necessary when necessary. As an example of a drop-on-demand type inkjet head, there is a piezoelectric inkjet head. The piezoelectric inkjet head includes an ink supply channel, a nozzle and a plurality of pressure chambers connected to the ink supply channel, and a piezoelectric element that applies pressure to the ink filled in the pressure chamber.

[0003] In a piezoelectric inkjet head, there is known a control method in which an ink meniscus is vibrated in advance and the pressure chamber is contracted in accordance with the phase of the resonance period, thereby efficiently ejecting the ink (for example, Patent Document 1). The period of the meniscus vibration is determined by the shape and capacity of the pressure chamber, the resistance of the throttle channel connected to the pressure chamber, and the like.

[0004] For high-definition printing, atomization of the ink ejected from the nozzle is desired. In order to atomize the ink, it is effective to reduce at least one of the ejection speed, the cross-sectional area of the nozzle, or the resonance period.

[0005] If the ejection speed is reduced, it becomes more susceptible to the influence of the air flow, resulting in disrupted ink landing accuracy, increased mist, or difficulty in the ink droplets flying straight. If the nozzle cross-sectional area is reduced, the ink may dry and clog at the tip of the nozzle, or the ejection angle of the ink may change. Also, to shorten the resonance period, there are methods such as reducing the volume of the pressure chamber or increasing the cross-sectional area of the throttle flow path. However, when such methods are adopted, as a side effect, the pressure wave of the meniscus vibration may be transmitted through the common flow path to the adjacent nozzle, which may have an adverse effect on the operation of the adjacent nozzle. Such an adverse effect on the adjacent nozzle is called crosstalk and the like.

[0006] An inkjet head that atomizes ink by reducing the resonance period without unnecessarily reducing the nozzle cross-sectional area and can suppress the deterioration of crosstalk due to reducing the resonance period is disclosed in Patent Document 2.

[0007] The inkjet head of Patent Document 2 is provided with an intermediate chamber and two throttle flow paths between the pressure chamber and the common flow path, so that the influence of the pressure fluctuation of the ink in the pressure chamber is less likely to be transmitted to the common flow path, and thus it is possible to achieve both atomization of the ejected ink and suppression of crosstalk.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] It is desired to further develop the technology disclosed in Patent Document 2 to further suppress ejection abnormalities due to crosstalk and to achieve atomization of the ejected liquid.

[0010] An object of the present disclosure is to provide a liquid ejection head and a printing apparatus capable of achieving both atomization of a discharged liquid and suppression of crosstalk.

Means for Solving the Problems

[0011] A liquid ejection head according to an aspect of the present disclosure includes a pressure chamber connected to a nozzle that ejects a liquid, a common flow path that supplies the liquid to the pressure chamber, and an intermediate chamber disposed between the pressure chamber and the common flow path and connected to the pressure chamber and the common flow path by throttle flow paths, respectively, and a volume of the intermediate chamber is larger than a volume of the pressure chamber.

[0012] A printing apparatus according to an aspect of the present disclosure includes the above-described liquid ejection head, a moving mechanism that relatively moves a printing object with respect to the liquid ejection head, and a control unit that controls the liquid ejection head and the moving mechanism.

Advantages of the Invention

[0013] According to the present invention, it is possible to achieve both atomization of a discharged liquid and suppression of crosstalk.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, detailed descriptions that are more detailed than necessary, for example, detailed descriptions of well-known matters and duplicate descriptions of substantially the same configurations may be omitted in some cases.

[0016] [Printing device 200] FIG. 1 is a top view of the printing device 200. In the present embodiment, an orthogonal coordinate system (X, Y, Z) will be used for the description. Hereinafter, the directions along the X-axis, Y-axis, and Z-axis will be referred to as the "X-axis direction", "Y-axis direction", and "Z-axis direction", respectively. In the example shown in FIG. 1, the installation surface of the printing device 200 is the XY plane, and the direction perpendicular to the installation surface is the Z-axis direction. In FIG. 1, for example, the X-axis and Y-axis are included in the horizontal plane, and the Z-axis is set along the vertical direction. However, in the present disclosure, the printing device does not necessarily have to be installed on a horizontal plane, and a slight inclination may be allowed.

[0017] The printing device 200 includes a base 1, a guide 2, a conveyance table 3, a gantry 4, a liquid discharge head 10, and a drive unit 7.

[0018] The base 1 is a base member that instructs each component of the printing device 200.

[0019] The gantry 4 supports the liquid discharge head 10.

[0020] The guide 2 is fixed to the upper surface of the base 1 along the longitudinal direction of the base 1, that is, the X-axis direction. The guide 2 guides the movement of the conveyance table 3.

[0021] The transfer table 3 holds a printing object 6 such as a substrate. The transfer table 3 is moved along the guide 2 together with the printing object 6 by the drive unit 7. As the printing object 6 moves, the liquid discharge head 10 discharges a liquid such as ink, thereby performing printing on the printing object 6.

[0022] In the example shown in FIG. 1, two liquid discharge heads 10 are respectively arranged on both sides of the gantry 4 along the X-axis direction, but the liquid discharge head 5 may be arranged on only one side of the gantry 4. Also, a plurality of gantries 4 may be provided.

[0023] [Liquid discharge head 10] The liquid discharge head 10 is an example of an ink circulation type inkjet head. FIG. 2 is an exploded perspective view of the liquid discharge head 10. In FIG. 2, the negative direction of the Z-axis is the ink discharge direction in the liquid discharge head 10, the direction along the Y-axis is the nozzle 101 arrangement direction, and the direction along the X-axis is the ink flow direction with respect to the pressure chamber 103.

[0024] The liquid discharge head 10 is composed of a nozzle plate 11, a flow path plate 12, a vibration plate 13, a housing 14, and a pressure fluctuation unit 15.

[0025] The nozzle plate 11 is arranged such that the plate surface is orthogonal to the Z-axis. The nozzle plate 11 is formed of, for example, a stainless steel (SUS) material, a silicon material, or a glass material formed by etching or press working. The thickness of the nozzle plate 11 is, for example, 100 μm when formed of a stainless steel plate. A plurality of nozzles 101 are formed through the nozzle plate 11 along the Y-axis. In FIG. 1, an example is shown in which the nozzles 101 arranged along the Y-axis direction are provided in two rows along the X-axis direction, but in the present disclosure, the nozzles may be provided in one row or three or more rows.

[0026] The flow path plate 12 has a rectangular parallelepiped shape and is arranged on the positive side of the nozzle plate 11 in the Z-axis direction such that the plate surface is orthogonal to the Z-axis. The flow path plate 12 is sandwiched between the vibration plate 13 and the nozzle plate 11. The flow path plate 12 is, for example, a laminate of a plurality of stainless steel plates formed by etching or press working. The thickness of each stainless steel plate is, for example, 10 μm or more and 100 μm or less, and the number of laminations is, for example, 3 or more and 10 or less.

[0027] The vibration plate 13 is arranged on the positive side of the flow path plate 12 in the Z-axis direction such that the plate surface is orthogonal to the Z-axis. The vibration plate 13 is sandwiched between the housing 14 and the flow path plate 12. The vibration plate 13 is, for example, a thin film having a thickness of 5 μm or more and 50 μm or less, and is formed of, for example, polyimide (Pi), SUS, or nickel (Ni) formed by an electroforming method.

[0028] Further, the vibration plate 13 has a pressure receiving portion 113 that receives pressure from the piezoelectric element 112. The pressure receiving portion 113 is provided corresponding to each of the plurality of pressure chambers 103. The pressure receiving portion 113 is formed to protrude positively in the Z-axis direction from a first wall body 114 that is, for example, a wall body on the positive side of the pressure chamber 103 in the Z-axis direction.

[0029] The housing 14 has a rectangular parallelepiped shape and is arranged on the positive side of the vibration plate 13 in the Z-axis direction. The thickness of the housing 14 along the Z-axis direction is, for example, 1 cm. The housing 14 is formed, for example, by cutting an alloy steel such as stainless steel.

[0030] The pressure fluctuation portion 15 is arranged in a part (accommodation chamber) of the housing 14 and pressurizes the ink stored in the pressure chamber 103 to generate pressure fluctuations. The pressure fluctuation portion 15 has a piezoelectric element 112. The operation of the piezoelectric element 112 is controlled by a control board such as a flexible printed board on which a control IC is mounted. The control IC individually controls the voltage applied to the plurality of piezoelectric elements 112.

[0031] The nozzle plate 11, the flow path plate 12, the flow path plate 12 and the vibration plate 13, the vibration plate 13 and the housing 14, and the vibration plate 13 and the pressure fluctuation unit 15 are each adhesively fixed with an adhesive. As the adhesive, for example, an epoxy-based adhesive having thermosetting properties is used. Note that the adhesives for adhering the respective components may be the same adhesive or different adhesives. For example, a rubber-based adhesive and an epoxy-based adhesive may be used in combination.

[0032] Inside the nozzle plate 11, the flow path plate 12, the vibration plate 13, the housing 14, and the pressure fluctuation unit 15, or by combining these, each element of the liquid ejection head 10 is formed.

[0033] FIG. 3 is a cross-sectional view showing the internal configuration of the liquid ejection head 10. In FIG. 3, the liquid flow path of one nozzle 101 in the liquid ejection head 10 is schematically shown.

[0034] The liquid ejection head 10 has a nozzle 101, a silo 102, a pressure chamber 103, a first throttle flow path 104, an intermediate chamber 105, a first damper 106, a second damper 107, a second throttle flow path 108, a common flow path 109, a third damper 110, a filter 111, a piezoelectric element 112, and a convex portion 115. In this specification, the first throttle flow path 104 and the second throttle flow path 108 may be collectively referred to simply as the throttle flow path 116. Note that in this specification, the throttle flow path means a flow path formed with a smaller cross-sectional area than the surrounding structure in the liquid flow direction. In the present embodiment, the throttle flow path 116 is formed so that its cross-section is square, and it is desirable that the shortest side of the square is in the Z-axis direction, and the length of the shortest side is 30 μm or less, desirably 20 μm or less.

[0035] The liquid ejection head 10 ejects liquid from the nozzle 101 by pressurizing the liquid in the pressure chamber 103 with the piezoelectric element 112.

[0036] The nozzle 101 is a hole drilled through the nozzle plate 11 in the Z-axis direction.

[0037] The diameter of the nozzle 101 is set to a size that is easy to prevent clogging due to particles that may be contained in the liquid, clogging that may occur due to the liquid level of the liquid exposed to the outside drying from the tip of the nozzle 101, etc. Further, the diameter of the nozzle 101 is set to a size that is easy to prevent problems such as the droplets (liquid droplets) of the liquid to be discharged becoming too large or the residual vibration of the liquid remaining in the nozzle 101 after the discharge of the liquid droplets being difficult to subside.

[0038] As an example, the diameter (minimum diameter) of the nozzle 101 is 5 μm or more and 50 μm or less. Preferably, the diameter of the nozzle 101 is 12 μm or more. More preferably, the diameter of the nozzle 101 is 15 μm or more and 20 μm or less. The cross-sectional shape of the nozzle 101 may be a tapered shape as shown in FIG. 3, or may be a rectangular shape. Further, the wall surface of the nozzle 101 may have a linear cross-section or a curved cross-section.

[0039] As shown in FIG. 1 and the like, a plurality of nozzles 101 are arranged along the Y-axis direction, and FIG. 3 shows the cross-section of one of the nozzles 101.

[0040] When a plurality of rows of the nozzles 101 are provided along the X-axis direction, the silo 102, the pressure chamber 103, the first throttle flow path 104, the intermediate chamber 105, the first damper 106, the second damper 107, and the second throttle flow path 108 are formed in a plurality of rows corresponding to the arrangement of the respective nozzles 101. The common flow path 109 and the third damper 110 may be provided for each arrangement of the nozzles 101, or may be shared by the arrangements of a plurality of nozzles 101.

[0041] The pressure chamber 103 and the silo 102 are provided for each of the plurality of nozzles 101. The pressure chamber 103 is connected to the nozzle 101 via the silo 102. Through the nozzle 101 and the silo 102, the liquid in the pressure chamber 103 is discharged to the outside.

[0042] The pressure chamber 103 is a liquid storage space formed by the flow path plate 12 and the vibration plate 13. The pressure chamber 103 is connected to the nozzle 101 that discharges the liquid via the silo 102. In the present embodiment, the pressure chamber 103 is formed by the recess formed in the flow path plate 12 being blocked by the vibration plate 13. The pressure chamber 103 has, for example, a rectangular parallelepiped shape extending along the X-axis. Steps may be formed on the inner surface of the pressure chamber 103. However, in the present disclosure, the shape of the pressure chamber may be any shape.

[0043] On the first wall body 114, which is the positive-side wall body of the pressure chamber 103 in the Z-axis direction, a pressure receiving portion 113 for transmitting the pressure from the piezoelectric element 112 into the pressure chamber 103 is provided. When the first wall body 114 flexes due to the operation of the piezoelectric element 112, the volume of the pressure chamber 103 decreases and the pressure of the liquid in the pressure chamber 103 increases, so that the liquid is discharged to the outside via the silo 102 and the nozzle 101.

[0044] The silo 102 is formed along the Z-axis direction and connects the pressure chamber 103 and the nozzle 101. The silo 102 forms a liquid storage space together with the pressure chamber 103. The silo 102 has, for example, a cylindrical shape or a quadrangular prism shape. In the present disclosure, the silo connecting the pressure chamber and the silo may not be formed, and for example, a nozzle may be directly formed on a part of the wall body of the pressure chamber.

[0045] In the present embodiment, a first throttle passage 104, an intermediate chamber 105, a first damper 106, a second damper 107, a second throttle passage 108, a common passage 109, a third damper 110, a filter 111, and a convex portion 115 are provided on both sides in the X-axis direction with respect to one nozzle 101, a silo 102, a pressure chamber 103, and a piezoelectric element 112. In the present embodiment, when the liquid is not being discharged from the nozzle 101, the liquid flowing through the common passage 109 on the positive side in the X-axis direction from the pressure chamber 103 is supplied to the pressure chamber 103 via the second throttle passage 108, the intermediate chamber 105, and the second throttle passage 108 provided on the positive side in the X-axis direction from the pressure chamber 103, and flows out from the pressure chamber 103 to the common passage 109 on the negative side in the X-axis direction via the first throttle passage 104, the intermediate chamber 105, and the second throttle passage 108 on the negative side in the X-axis direction from the pressure chamber 103. In FIG. 3, the flow direction of the liquid flowing inside the liquid discharge head 10 in the present embodiment is indicated by a broken-line arrow.

[0046] In the present disclosure, the flow direction of the liquid is not limited to the example shown in FIG. 3. For example, the liquid may flow in the direction opposite to the example shown in FIG. 3. Further, when the liquid discharge head of the present disclosure has a plurality of rows of nozzle arrays, the flow direction of the liquid in each array may not be the same direction. Further, the filter 111 may be disposed only on the upstream side, and in this case, a mere opening may be provided on the downstream side.

[0047] The first throttle passage 104 is a passage connecting the pressure chamber 103 and the intermediate chamber 105.

[0048] The thickness of the first throttle passage 104 along the Z-axis direction is, for example, 20 μm or less. The width of the first throttle passage 104 along the Y-axis direction is, for example, 50 μm or more and 700 μm or less. The length of the first throttle passage 104 along the X-axis direction is 50 μm or more and 500 μm or less.

[0049] In the example shown in FIG. 3, the length of the first throttle passage 104 on the positive side in the X-axis direction from the pressure chamber 103 and the length of the first throttle passage 104 on the negative side in the X-axis direction from the pressure chamber 103 are made different from each other. Specifically, the length of the first throttle passage 104 on the negative side in the X-axis direction is made shorter than the length of the first throttle passage 104 on the positive side in the X-axis direction. Also, the position of the nozzle 101 in the X-axis direction is shifted to the negative side from the central position of the pressure chamber 103 in the X-axis direction and arranged.

[0050] As a result, when liquid is discharged from the nozzle 101 and the pressure of the liquid in the pressure chamber 103 decreases, since the nozzle 101 is closer to the negative side from the central position, the pressure of the liquid in the vicinity of the first throttle passage 104 inside the pressure chamber 103 is smaller on the negative side where the nozzle 101 is closer than on the positive side where the nozzle 101 is not closer. By making the length of the first throttle passage 104 on the negative side where the pressure of the liquid becomes smaller shorter than the length of the first throttle passage 104 on the positive side, it becomes easier to maintain the pressure of the liquid evenly in the vicinity of the first throttle passages 104 on both the positive and negative sides.

[0051] The intermediate chamber 105 is arranged between the pressure chamber 103 and the common passage 109, and is connected to the pressure chamber 103 and the common passage 109 by throttle passages 116 (the first throttle passage 104 and the second throttle passage 108). The intermediate chamber 105 is a liquid storage part that temporarily stores the liquid flowing in from the common passage 109 or the pressure chamber 103. By storing the liquid in the intermediate chamber 105, liquid resonance can be generated in the fluid system composed of the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105. As a result, a relatively short resonance period can be realized, and an effect of suppressing the pressure applied from the piezoelectric element 112 to the liquid in the pressure chamber 103 from being transmitted to the adjacent nozzle 101 can be obtained.

[0052] In this embodiment, the volume of the intermediate chamber 105 is larger than the volume of the pressure chamber 103. Preferably, the volume of the intermediate chamber 105 is at least twice the volume of the pressure chamber 103. With such a configuration, the liquid ejection head 10 of this embodiment can atomize the liquid ejected from the nozzle 101 by making the resonance period relatively short, and can suppress the occurrence of ejection abnormalities due to crosstalk. The mechanism by which the volume of the intermediate chamber 105 is made larger than the volume of the pressure chamber 103, and the ejected liquid droplets can be atomized by making the resonance period relatively short and the occurrence of ejection abnormalities due to crosstalk can be suppressed will be described in detail later.

[0053] In the example shown in FIG. 3, in both the length in the X-axis direction and the length in the Z-axis direction, the intermediate chamber 105 is formed larger than the pressure chamber 103, so that the volume of the intermediate chamber 105 is larger than the volume of the pressure chamber 103. For miniaturization of the liquid ejection head 10, the intermediate chamber 105 may be expanded along the Z-axis direction rather than along the X-axis direction.

[0054] The intermediate chamber 105 has a first damper 106 and a second damper 107 at a position facing the first damper 106. The first damper 106 is provided on the positive side in the Z-axis direction of the intermediate chamber 105. The second damper 107 is provided on the negative side in the Z-axis direction of the intermediate chamber 105. A space for releasing pressure is provided on the negative side in the Z-axis direction from the second damper 107.

[0055] The first damper 106 and the second damper 107 are formed with different thicknesses. Further, the first damper 106 and the second damper 107 have different natural frequencies.

[0056] The thickness of the first damper 106 is, for example, 5 μm or less. The thickness of the second damper is, for example, 20 μm or less. The lengths of the first damper 106 and the second damper 107 along the longitudinal direction of the intermediate chamber 105, that is, the X-axis direction, are 200 μm or more. Note that the length of the first damper 106 and the length of the second damper 107 may be different from each other. Further, the first damper 106 and the second damper 107 may each be divided in the Y-axis direction. In this case, the divided first damper or second damper may each have a different natural frequency.

[0057] The second throttle flow path 108 is a flow path that connects the intermediate chamber 105 and the common flow path 109. The second throttle flow path 108 is provided coaxially with the first throttle flow path 104 or parallel in the X-axis direction.

[0058] The thickness of the second throttle flow path 108 along the Z-axis direction is, for example, 20 μm or less. The width of the second throttle flow path 108 along the Y-axis direction is, for example, 50 μm or more and 300 μm or less. The length of the second throttle flow path 108 along the X-axis direction is, for example, 50 μm or more and 300 μm or less.

[0059] In the present embodiment, the fluid resistance of the first throttle flow path 104 is formed to be larger than the fluid resistance of the second throttle flow path 108. Note that the fluid resistance means the magnitude of the resistance applied to the fluid flowing through a certain flow path under the condition that the viscosity and flow velocity of the fluid are constant. Further, in the present embodiment, the length of the second throttle flow path 108 is formed to be shorter than the length of the first throttle flow path 104. The reason is as follows.

[0060] The throttle flow path 116 including the first throttle flow path 104 and the second throttle flow path 108 has an effect of suppressing the transmission of the pressure fluctuation for liquid ejection in the pressure chamber 103 to the adjacent nozzle 101. As described above, by storing the liquid in the intermediate chamber 105, the same effect can be obtained.

[0061] Here, in order to miniaturize the liquid ejection head 10, it is desirable to shorten the total length along the X-axis direction of the intermediate chamber 105 and the throttle flow path 116. At this time, there is a strong correlation between the length of the first throttle flow path 104 and the volume of the liquid droplets ejected from the nozzle 101. Therefore, when designing the liquid ejection head 10, the length of the first throttle flow path 104 is determined based on the droplet volume of the liquid ejection head 10 to be manufactured. On the other hand, from experiments and the like, it is known that expanding the volume of the intermediate chamber 105 has a greater effect of attenuating the pressure fluctuations in the pressure chamber 103 than lengthening the second throttle flow path 108. Therefore, it can be expected that even if the second throttle flow path 106 is shortened, the effect of sufficiently attenuating the pressure fluctuations will be exhibited. If the second throttle flow path 106 is not provided, the effect of attenuating the pressure fluctuations by the intermediate chamber 105 cannot be obtained. Therefore, it is very effective to arrange the second throttle flow path 106 even if it is short. From the above, the length of the second throttle flow path 106 is preferably shorter than the length of the first throttle flow path 104, for example, 50 μm or more and 300 μm or less.

[0062] In this way, by making the length of the second throttle flow path 108 shorter than the length of the first throttle flow path 104, liquid resonance can be generated in the fluid system composed of the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105 to realize a relatively short resonance period. At the same time, it is possible to achieve both the effect of preventing the pressure applied to the liquid in the pressure chamber 103 from the piezoelectric element 112 from propagating to the adjacent nozzle 101 and the miniaturization of the liquid ejection head 10.

[0063] Also, as described above, in a state where the piezoelectric element 112 is not driven and no liquid is discharged from the nozzle 101, the liquid circulates by continuously flowing from the upstream common flow path 109 to the downstream common flow path 109. At this time, the flow path resistance applied to the liquid in the entire flow path from the upstream common flow path 109 to the downstream common flow path 109 can be regarded as the sum of the flow path resistances of the first throttle flow path 104 and the second throttle flow path 108 in series. From the viewpoint of circulating the liquid in the liquid discharge head 10, the smaller the flow path resistance of the entire flow path, the easier it is to control the flow rate of the circulating liquid. Therefore, it is better that the flow path resistances of the first throttle flow path 104 and the second throttle flow path 108 are each small. As described above, since the length of the first throttle flow path 104 is determined by the required droplet volume, in order to reduce the flow path resistance of the entire flow path, it is desirable to make the length of the second throttle flow path 108 shorter than the length of the first throttle flow path 104.

[0064] The common flow path 109 is a flow path that circulates the liquid supplied to the nozzle 101 along the Y-axis direction. The common flow path 109 is connected to the entire flow path provided in the housing 14 shown in FIG. 2 via the filter 111. The entire flow path is connected to the liquid tank 210 shown in FIG. 1 and supplies the liquid from the liquid tank 210 to the liquid discharge head 10.

[0065] The common flow path 109 has a third damper 110. By providing the third damper 110 in addition to the intermediate chamber 105 and the second throttle flow path 108, it is possible to more effectively prevent the situation where the pressure applied to the liquid in the pressure chamber 103 propagates to the adjacent nozzle 101. The third damper 110 is provided at a position facing the filter 111 in the common flow path 109. A space for the third damper 110 to release pressure is provided on the negative side in the Z-axis direction from the third damper 110.

[0066] In the example shown in FIG. 3, for one nozzle 101 and pressure chamber 103, on the upstream side and the downstream side in the liquid flow direction, that is, on both the positive and negative sides in the X-axis direction, a first throttle flow path 104, an intermediate chamber 105, a second throttle flow path 108, and a common flow path 109 are arranged respectively. Here, the shapes of the first throttle flow path 104, the intermediate chamber 105, the second throttle flow path 108, and the common flow path 109 may be different from each other, for example, between the upstream side and the downstream side. Specifically, the lengths of the first throttle flow path 104 and the second throttle flow path 108 along the liquid flow direction (X-axis direction) may be different between the upstream side and the downstream side. The volume of the intermediate chamber 105 may be different between the upstream side and the downstream side. The lengths of the first damper 106 and the second damper 107 provided in the intermediate chamber 105 along the flow direction may be different from each other between the upstream side and the downstream side. In this case, it is sufficient that the first damper 106 and the second damper 107 closer to the nozzle 101 in the flow direction are formed shorter than the first damper 106 and the second damper 107 farther from the nozzle 101.

[0067] Moreover, the present disclosure is not limited to a configuration in which a first throttle flow path 104, an intermediate chamber 105, a second throttle flow path 108, and a common flow path 109 are arranged on the upstream side and the downstream side in the liquid flow direction for one nozzle 101 and pressure chamber 103. For example, for one nozzle and pressure chamber, only one first throttle flow path, intermediate chamber, second throttle flow path, and common flow path may be arranged.

[0068] The filter 111 is a member that covers the positive side in the Z-axis direction of the common flow path 109. The filter 111 has a plurality of through holes. The diameters of the plurality of through holes are set to values that allow the liquid to pass through and do not allow particles that may cause the nozzle 101 to clog to pass through. It is desirable that the through holes of the filter 111 have an opening smaller than that of the nozzle 101, and the diameter of the through holes may be set, for example, to be 3 μm or more and 20 μm or less.

[0069] The piezoelectric element 112 is a pressure source that applies pressure to the liquid in the pressure chamber 103. The piezoelectric element 112 is in contact with the pressure receiving portion 113 via an adhesive. When a voltage is applied to the piezoelectric element 112 based on control by a control unit 230 shown in FIG. 1, for example, it deforms so as to expand and contract in the Z-axis direction. For the piezoelectric element 112, for example, a laminated piezoelectric actuator in the D33 mode is used.

[0070] Next, with reference to FIGS. 4 to 6, an example of the laminated structure of the liquid ejection head 10 will be described. FIG. 4 is a plan view of the nozzle plate 11. FIG. 5 is a plan view of a plurality of laminates constituting the flow path plate 12. FIG. 6 is a plan view of the vibration plate 13. In FIGS. 4 to 6, each laminated structure is shown in a plan view as viewed from the positive side in the Z-axis direction.

[0071] The nozzle plate 11 is made of, for example, a material obtained by stretching SUS (Steel Use Stainless). A plurality of nozzles 101 are formed along the Y-axis direction on the nozzle plate 11. As a processing method for the nozzles 101, laser processing, punching processing, etching processing, etc. may be appropriately adopted. Note that FIG. 4 shows an example in which an array of nozzles 101 is formed in one row on the nozzle plate 11. When a plurality of arrays of nozzles 101 are provided, the arrays of nozzles 101 may be formed along the X-axis direction on the nozzle plate 11.

[0072] The flow path plate 12 is configured by laminating a first laminate 121, a second laminate 122, a third laminate 123, a fourth laminate 124, a fifth laminate 125, a sixth laminate 126, and a seventh laminate 127 in order from the negative side to the positive side in the Z-axis direction. FIG. 5A is a plan view of the first laminate 121. FIG. 5B is a plan view of the second laminate 122. FIG. 5C is a plan view of the third laminate 123. FIG. 5D is a plan view of the fourth laminate 124. FIG. 5E is a plan view of the fifth laminate 125. FIG. 5F is a plan view of the sixth laminate 126. FIG. 5G is a plan view of the seventh laminate 127.

[0073] The first laminate 121, the second laminate 122, the third laminate 123, the fourth laminate 124, the fifth laminate 125, the sixth laminate 126, and the seventh laminate 127 are made of, for example, a material obtained by stretching SUS. The laminates may be bonded to each other with an adhesive or the like, or may be bonded by thermal diffusion bonding or the like.

[0074] An opening penetrating in the Z-axis direction is formed in each of the first laminate 121 to the seventh laminate 127. FIG. 5 shows the reference numerals of the configuration of the liquid ejection head 10 corresponding to each opening.

[0075] The first laminate 121 has an opening corresponding to the silo 102, and openings corresponding to the spaces for the second damper 107 and the third damper 110 to release pressure. The thickness of the first laminate 121 is, for example, 30 μm or more and 100 μm or less.

[0076] The second laminate 122 has an opening corresponding to the silo 102. In FIG. 5B, the positions corresponding to the first damper and the third damper 110 in the first laminate 112 are indicated by broken lines. Actually, the positions of the broken lines of the second laminate 122 are just planes. The thickness of the second laminate 122 is, for example, 10 μm or more and 25 μm or less.

[0077] The third laminate 123 and the fourth laminate have openings corresponding to the silo 102, the intermediate chamber 105, and the common flow path 109. The thickness of the third laminate 123 and the fourth laminate is, for example, 20 μm or more and 100 μm or less.

[0078] The fifth laminate 125 has openings corresponding to the pressure chamber 103, the intermediate chamber 105, and the common flow path 109. The thickness of the fifth laminate 125 is, for example, 20 μm or more and 100 μm or less.

[0079] The sixth laminate 126 has openings corresponding to the pressure chamber 103, the first throttle passage 104, the intermediate chamber 105, the second throttle passage 108, and the common passage 109. Although no boundaries are formed between each of the pressure chamber 103, the first throttle passage 104, the intermediate chamber 105, the second throttle passage 108, and the common passage 109 in the openings of the sixth laminate 126, in FIG. 5F, the positions corresponding to the boundaries are indicated by broken lines. Thus, the first throttle passage 104 and the second throttle passage 108 are formed at the same position in the Z-axis direction of the flow path plate 12. The thickness of the sixth laminate 126 is, for example, 10 μm or more and 30 μm or less.

[0080] The seventh laminate 127 has openings corresponding to the pressure chamber 103, the intermediate chamber 105, and the common passage 109. The thickness of the seventh laminate 127 is, for example, 30 μm or more and 100 μm or less.

[0081] As shown in FIGS. 5D to 5F, partitions 118 are provided in the fourth laminate 124, the fifth laminate 125, and the sixth laminate 126 along the Y-axis direction. As shown in FIGS. 5C and 5G, partitions 118 are not provided in the most positive region and the most negative region in the Z-axis direction of the common passage 109. This partition 118 is provided, for example, to improve the strength of the flow path plate 12. However, in the liquid ejection head of the present disclosure, the partition may not be provided.

[0082] By laminating the first laminate 121 to the third laminate 123, the second damper 107 and the third damper 110 are configured. Further, by laminating the first laminate 121 to the fourth laminate 124, the silo 102 is configured.

[0083] By laminating the seventh laminate 127 on top of the third laminate 123, the pressure chamber 103, the intermediate chamber 105, and the common flow path 109 are formed. By laminating the seventh laminate 127 on top of the fifth laminate 125, the first throttle flow path 104 and the second throttle flow path 108 are formed. In the present disclosure, the first throttle flow path and the second throttle flow path may be formed by another laminate such as the third laminate to the fifth laminate.

[0084] The vibration plate 13 has a region corresponding to the filter 111, a thin portion 117 corresponding to the first damper 106 and the first wall body 114, and a pressure receiving portion 113 and a convex portion 115. The thickness of the vibration plate 13 is, for example, 10 μm or more and 30 μm or less. The vibration plate 13 is made of, for example, polyimide (Pi), SUS, or nickel (Ni) formed by an electroforming method. In the present disclosure, the filter 111 may not be provided, and a simple opening may be formed instead of the filter. Also, a filter may be provided in the common flow path on the upstream side in the liquid flow direction, and an opening may be formed without providing a filter in the common flow path on the downstream side.

[0085] The convex portion 115 is a protrusion that protrudes facing the first partition wall 118 that separates the pressure chamber 103 and the intermediate chamber 105 between the first damper 106 and the first wall body 114. The length of the convex portion 115 in the X-axis direction is formed to be the same as or shorter than the length of the first partition wall 118 in the X-axis direction.

[0086] When manufacturing the liquid ejection head 10, when joining the vibration plate 13 including the pressure receiving portion 113, the first wall body 114, the convex portion 115, and the first damper 106 to the flow path plate 12, by physically pushing the convex portion 115 from the positive side in the Z-axis direction, the vibration plate 13 can be firmly joined to the flow path plate 12.

[0087] The thin portion 117 is a region formed thinner than the surroundings. The thickness of the thin portion 117 is, for example, 2 μm or more and 10 μm or less. The pressure receiving portion 113 and the convex portion 115 are formed inside the region of the thin portion 117.

[0088] Thus, the first damper 106 and the first wall 114, which is a part of the wall of the pressure chamber 103, are integrally formed by the thin portion 117. Thereby, the material constituting the thin portion 117 can be effectively utilized, and the manufacturing cost can be reduced. Further, since there is no need for the cost of separately forming a separate member for the first damper 106 and the first wall 114, the entire liquid discharge head 10 can be miniaturized and the cost can be reduced.

[0089] The nozzle plate 11 is joined to the negative side in the Z-axis direction of the flow path plate 12 formed by laminating the first laminate 121 to the seventh laminate 127. Thereby, the nozzle 101 is disposed on the negative side in the Z-axis direction of the silo 102.

[0090] Further, the vibration plate 13 is joined to the positive side in the Z-axis direction of the flow path plate 12. As described above, at this time, by physically pressing the convex portion 115 from the positive side in the Z-axis direction, the vibration plate 13 is firmly joined to the flow path plate 12. Thereby, the openings provided in the third laminate 123 to the seventh laminate 127 of the flow path plate 12 are covered by the vibration plate 13, and the pressure chamber 103, the intermediate chamber 105, and the common flow path 109 are formed.

[0091] [Effects Obtained by the Liquid Discharge Head 10] Hereinafter, the effects obtained by the liquid discharge head 10 having the above-described configuration and the principle thereof will be described in detail.

[0092] Generally, in order to perform high-precision printing, there is a desire to reduce the size of the liquid droplets ejected by the liquid ejection head. Generally, in a piezoelectric liquid ejection head, there is generally a relationship approximately as shown in the following equation (1) between the volume V of the ejected liquid droplet, the cross-sectional area S of the nozzle, the ejection speed v, and the resonance frequency (Helmholtz frequency) f of the fluid system in the liquid ejection head. Note that in Equation (1), the influence given by the applied voltage waveform, the ligament length determined by the viscosity of the liquid, etc. is not considered, but it is fully possible to grasp the relationship between the volume V of the ejected liquid droplet, the cross-sectional area S of the nozzle, the ejection speed v, and the resonance frequency f. V = (S × v) / (2 × f) (1)

[0093] As described above, in order to prevent clogging of the liquid in the nozzle, it is desirable not to make the cross-sectional area S of the nozzle unnecessarily small. Also, if the liquid ejection speed v is decreased, problems such as an increase in ejection instability or deterioration of robustness may occur, so it is desirable not to make the ejection speed v unnecessarily slow.

[0094] According to Equation (1), in order to reduce the volume V of the ejected liquid droplet without making the nozzle cross-sectional area S unnecessarily small and without making the ejection speed v unnecessarily slow, the resonance frequency f may be increased, or in other words, the resonance period may be shortened. As a method of shortening the resonance period, there are methods such as reducing the volume of the pressure chamber or reducing the resistance of the throttle flow path.

[0095] However, when the resonance period is shortened by reducing the volume of the pressure chamber or reducing the resistance of the throttle flow path, the pressure fluctuation of the liquid in the pressure chamber easily propagates to other adjacent nozzles via the throttle flow path and the common flow path. In this case, crosstalk occurs in which the pressure fluctuation of the liquid has an adverse effect on the liquid ejection in the adjacent nozzles.

[0096] The liquid ejection head 10 according to an embodiment of the present disclosure reduces the volume of the pressure chamber 103 and utilizes the resonance period of the liquid in the flow system composed of the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105 to eject small droplets of ink. As a result, the nozzle cross-sectional area can be made as large as possible, the ejection speed v can be made as fast as possible, and the resonance period can be shortened to reduce the volume V of the ejected liquid droplets, while preventing the deterioration of crosstalk.

[0097] Note that simply reducing the volume of the pressure chamber 103 or reducing the flow path resistance to shorten the resonance period makes it easier for the pressure fluctuation of the liquid in the pressure chamber 103 to be transmitted to the adjacent nozzles, resulting in crosstalk. To suppress this, in the liquid ejection head 10 according to an embodiment of the present disclosure, an intermediate chamber 105 and two throttle flow paths, i.e., the first throttle flow path 104 and the second throttle flow path 108, are provided between the pressure chamber 103 and the common flow path 109, and the volume of the intermediate chamber 105 is made larger than the volume of the pressure chamber 103.

[0098] In the liquid ejection head 10 according to an embodiment of the present disclosure, the liquid is ejected from the nozzle 101 by utilizing the resonance of the liquid generated in the flow system composed of the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105. Here, the second throttle flow path 108 and the common flow path 109 outside the intermediate chamber 105 when viewed from the pressure chamber 103 are less likely to affect the resonance of the liquid for liquid ejection. The reason for this will be described later.

[0099] And by making the volume of the intermediate chamber 105 larger than the volume of the pressure chamber 103, the volume of the liquid that reaches the intermediate chamber 105 from the pressure chamber 103 via the first throttle flow path 104 expands. As a result, the pressure fluctuation generated in the pressure chamber 103 for ejecting the liquid is sufficiently attenuated by the expansion of the liquid in the intermediate chamber 105.

[0100] Note that in the liquid ejection head 10 of the present embodiment, as described above, droplets are ejected by utilizing the resonance of the liquid generated in the flow system composed of the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105. Here, when the intermediate chamber 105 is not sufficiently larger than the pressure chamber 103, the pressure fluctuation of the liquid generated in the pressure chamber 103 is not sufficiently attenuated and is transmitted to the common passage 109 through the second throttle passage 108. Therefore, resonance is not completed (the components for completion decrease) between the pressure chamber 103 and the intermediate chamber 105. In this case, in the liquid ejection head 10, the resonance generated in the system including the nozzle 101, the pressure chamber 103, the first throttle passage 104, the intermediate chamber 105, the second throttle passage 108, and the common passage 109 affects the resonance generated in the flow system composed of the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105. As a result, the resonance period in the liquid ejection head 10 becomes longer. As a result, in order to achieve droplet formation of the ejected droplets, it is necessary to adopt another measure such as reducing the nozzle diameter. Therefore, in the liquid ejection head 10 of the present embodiment, in addition to reducing the volume of the pressure chamber 103 and reducing the flow resistance of the first throttle passage 104, by making the volume of the intermediate chamber 105 sufficiently larger than the pressure chamber 103, it is possible to obtain the effect of sufficiently shortening the resonance period by utilizing the resonance of the liquid generated in the flow system composed of the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105.

[0101] With such a configuration, it is possible to obtain the effect of sufficiently shortening the resonance period by utilizing the resonance of the liquid generated in the flow system composed of the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105. In addition, the pressure fluctuation of the liquid generated in the pressure chamber 103 for liquid ejection is sufficiently attenuated by the intermediate chamber 105 and the second throttle passage 108, and it becomes difficult to be transmitted to the common passage 109. Therefore, the resonance period of the entire flow path system can be shortened, and crosstalk can be effectively suppressed.

[0102] Furthermore, in the liquid ejection head 10 according to the embodiment of the present disclosure, since the intermediate chamber 105 has the first damper 106, the effect of absorbing the pressure fluctuations propagated from the pressure chamber 103 can be significantly enhanced. As a result, among the plurality of resonances respectively occurring at various locations within the liquid flow path, the intensity of the resonance in the fluid system constituted by the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105 can be made relatively strong. That is, small droplets can be ejected with a relatively short resonance period, and among the pressure fluctuations of the liquid flowing into the intermediate chamber 105 through the first throttle flow path 104, the component directly flowing into the second throttle flow path 108 can be significantly reduced. That is, both the effect of shortening the resonance period to atomize the ejected droplets and the effect of reducing crosstalk can be enhanced. Furthermore, since the intermediate chamber 105 has the first damper 106 and the second damper 107, the residual vibration in the intermediate chamber 105 can be effectively attenuated. As a result, the effect of more effectively suppressing crosstalk and the effect of suppressing the influence of residual vibration when the liquid is ejected at a high frequency can be obtained. Here, by disposing the first damper 106 and the second damper 107 having different natural frequencies within the intermediate chamber 105, the residual vibration of the damper itself can also be suppressed at an early stage.

[0103] Furthermore, since the common flow path 109 has the third damper 110, even if the pressure fluctuations for liquid ejection reach the common flow path 109, the pressure fluctuations can be attenuated in the common flow path 109, and crosstalk can be more effectively suppressed.

[0104] Note that, apart from the resonance occurring in the fluid system including the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105 due to the liquid ejection, pressure fluctuations may occur in the pressure chamber 103 due to the natural vibrations of the first damper 106 and the second damper 107 respectively. Here, generally, in a liquid ejection head, the ejected droplets are ejected with ligaments (residues of liquid following the flying droplets). However, for high-definition printing, it is desirable that the droplets and the ligaments integrate and land before landing.

[0105] In the liquid ejection head 10 according to the embodiment of the present disclosure, after the liquid is ejected from the nozzle 101, the pressure fluctuations generated in the intermediate chamber 105 and the pressure chamber 103 by the first damper 106 can apply a force in the direction of pushing the ligament into the ejected droplets. As a result, it becomes easier to integrate the droplets and the ligaments, and high-definition printing can be performed.

[0106] FIG. 7 is a diagram showing an example of the relationship between the diameter of the nozzle 101 in the liquid ejection head 10, the resonance period for liquid ejection in the liquid ejection head 10, and the droplet volume. In FIG. 7, the ejection speed of the liquid is set to 6 m / s. Each straight line shown in the graph of FIG. 7 represents the relationship between the droplet volume and the resonance period when the diameter of the nozzle 101 is 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm. Note that the resonance period for liquid ejection is the resonance period of the liquid occurring in the fluid system composed of the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105.

[0107] In the liquid ejection head 10 of the present embodiment, as described above, the diameter of the nozzle 101 is preferably 12 μm or more, and more preferably 15 μm or more and 20 μm or less. This is because generally when the diameter of the nozzle is less than 12 μm, the liquid surface exposed from the nozzle tip dries and solidifies near the nozzle tip, deteriorating the mass productivity of the object to be printed.

[0108] According to FIG. 7, for example, when the liquid ejection head 10 is designed by setting the diameter of the nozzle 101 to 15 μm and the resonance period to about 3.8 μs, the droplets ejected from the nozzle 101 can be made into small droplets of 2 pL. Further, when it is desired to make the droplet volume 1 pL, for example, the liquid ejection head 10 may be designed such that the diameter of the nozzle 101 is 13 μm and the resonance period is about 2.5 μs. Note that the design of the liquid ejection head 10 includes structural design such as the diameter of the nozzle 101, the relationship between the volume of the pressure chamber 103 and the volume of the intermediate chamber 105, and the flow path cross-sectional areas of the first throttle flow path 104 and the second throttle flow path 108, and process design such as the waveform for ejecting droplets in accordance with the fluid resonance period.

[0109] As described above, in the present embodiment, based on the desired diameter of the nozzle 101 and the droplet volume, the resonance period for liquid ejection (that is, the resonance period of the flow path system constituted by the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105) is set to an appropriate value, and the liquid ejection head 10 is designed accordingly, whereby a liquid ejection head 10 capable of ejecting a desired droplet volume can be obtained. Here, in the liquid ejection head 10 according to the embodiment of the present disclosure, even when the diameter of the nozzle 101 is 12 μm or more, which is easy to process and less likely to be clogged, small droplets such as 1 pL and 2 pL can be ejected by making the resonance period relatively short without deteriorating fluid characteristics such as crosstalk. In particular, when printing a pattern on a high-definition display panel, small droplets such as 1 pL and 2 pL are desired, but the liquid ejection head 10 of the present embodiment can sufficiently meet such a demand.

[0110] Note that the resonance period for liquid ejection is determined by the volumes of the pressure chamber 103 and the intermediate chamber 105, and the magnitude of the resistance generated in the liquid flowing through the first throttle passage 104. In practice, the resonance period for liquid ejection can be estimated by performing a fluid simulation using, as parameters, the volumes of the pressure chamber 103 and the intermediate chamber 105, the flow path cross-sectional areas of the first throttle passage 104 and the second throttle passage 108, and the characteristics (such as viscosity) of the liquid. For practical use, the resonance period for liquid ejection may be derived and set by an experimental method as described below.

[0111] Note that the resonance period is the time from when the piezoelectric element 112 applies pressure to the liquid in the pressure chamber 103 until the meniscus (liquid surface) at the tip of the nozzle 101 moves in the positive (or negative) side in the Z-axis direction and then moves in the negative (or positive) side in the Z-axis direction and returns to the original liquid level position. The resonance frequency is the reciprocal of the resonance period. As an experimental method for setting the resonance period of the liquid ejection head 10, a general simulation method may be used in which the relationship between the waveform with the resonance period changed step by step and the ejection speed is experimentally derived, and the period with the highest speed (the best ejection efficiency) is extracted.

[0112] FIG. 8 is a diagram showing an example of the applied waveform applied to the piezoelectric element 112. The vertical axis of FIG. 8 is, for example, the applied voltage. The horizontal axis of FIG. 8 is time. At the time of designing the liquid ejection head 10, the waveform setting of the liquid ejection head may be performed so as to take the resonance period shown in FIG. 8 based on the resonance period derived by the above-described simulation.

[0113] As described above, the liquid ejection head 10 of the present embodiment can achieve the first effect and the second effect simultaneously. The first effect is an effect of making both the nozzle 101 larger in diameter and the ejected liquid droplets smaller by relatively shortening the resonance period related to liquid ejection. The second effect is an effect of effectively reducing the adverse effect (crosstalk) caused by the pressure during liquid ejection in one nozzle 101 propagating to adjacent nozzles. That is, the liquid ejection head 10 of the present embodiment can achieve both making the ejected liquid droplets smaller and suppressing crosstalk while making the cross-sectional area of the nozzle 101 as large as possible.

[0114] (Other effects) In addition to the first effect and the second effect described above, the liquid ejection head 10 of the present embodiment exhibits various effects as follows.

[0115] <Action, effect> As described above, the liquid ejection head 10 according to the embodiment of the present disclosure includes a pressure chamber 103 connected to a nozzle 101 that ejects liquid, a common flow path 109 that supplies liquid to the pressure chamber 103, and an intermediate chamber 105 disposed between the pressure chamber 103 and the common flow path 109 and connected to the pressure chamber 103 and the common flow path 109 by a throttle flow path 116. The volume of the intermediate chamber 105 is larger than the volume of the pressure chamber 103.

[0116] In the liquid ejection head 10 according to the embodiment of the present disclosure, liquid is ejected from the nozzle 101 by utilizing the resonance of the liquid generated in the fluid system constituted by the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105. Here, the second throttle flow path 108 and the common flow path 109 outside the intermediate chamber 105 as viewed from the pressure chamber 103 are less likely to affect the resonance of the liquid for liquid ejection.

[0117] Between the pressure chamber 103 where pressure fluctuations for liquid ejection occur and the common flow path 109, an intermediate chamber 105 having a larger volume than the pressure chamber 103 and a throttle flow path 116 (a first throttle flow path 104 and a second throttle flow path 108) are provided. As a result, the pressure fluctuations generated in the pressure chamber 103 for liquid ejection are attenuated by the intermediate chamber 105 and the throttle flow path 116, and it becomes difficult for them to be transmitted to the common flow path 109. By making the volume of the intermediate chamber 105 larger than the volume of the pressure chamber 103, the volume of the liquid reaching the intermediate chamber 105 from the pressure chamber 103 through the first throttle flow path 104 expands. Therefore, the pressure fluctuations for ejecting the liquid, which occur in the pressure chamber 103, are sufficiently attenuated in the intermediate chamber 105.

[0118] Also, by making the volume of the intermediate chamber 105 larger than the volume of the pressure chamber 103, the liquid in the pressure chamber 103 can be ejected from the nozzle 101 due to the resonance occurring in the fluid system composed of the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105. The influence of the relatively long resonance period in the system including the second throttle flow path 108 and the common flow path 109 on liquid ejection can be minimized. In this way, by making the volume of the intermediate chamber 105 larger than the volume of the pressure chamber 103, the resonance period in the liquid ejection head 10 according to the embodiment of the present disclosure can be shortened. As a result, it is possible to achieve both atomization of the ejected liquid droplets and suppression of crosstalk.

[0119] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the volume of the intermediate chamber 105 is twice or more that of the pressure chamber 103. With such a configuration, the robustness against the viscosity or flow rate of the liquid can be improved. Therefore, the effect of ejecting the liquid from the nozzle 101 by utilizing the resonance of the liquid generated in the flow system constituted by the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105 can be easily exhibited even for inks having different characteristics such as viscosity. That is, the intensity of the resonance of the liquid generated in the flow system constituted by the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105 can be relatively increased with respect to the vibration components generated at various locations in the ink flow path. Therefore, it is possible to eject small droplets using a short resonance period, and the effect of further suppressing crosstalk can be improved.

[0120] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the intermediate chamber 105 has a first damper 106. With such a configuration, the pressure applied to the liquid in the pressure chamber 103 during liquid ejection can be effectively attenuated in the intermediate chamber 105. Further, the effect of ejecting the liquid from the nozzle 101 by utilizing the resonance of the liquid generated in the flow system constituted by the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105 can be easily exhibited. That is, the intensity of the resonance of the liquid generated in the flow system constituted by the nozzle 101, the pressure chamber 103, the first throttle passage 104, and the intermediate chamber 105 can be relatively increased with respect to the vibration components generated at various locations in the ink flow path. Therefore, the function of absorbing the pressure in the intermediate chamber 105 can be strengthened, small droplets can be ejected using a short resonance period, and the effect of further suppressing crosstalk can be improved.

[0121] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the first damper 106 is integrally formed with the first wall body 114 of the pressure chamber 103 that is connected to the pressure receiving portion 113 that changes the volume of the pressure chamber 103. With such a configuration, compared with the case where the first wall body 114 and the first damper 106 are formed separately, the manufacturing process of the liquid ejection head 10 can be reduced, so that the manufacturing cost can be reduced and the material constituting the thin portion 117 can be effectively utilized.

[0122] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the throttle passage 116 has a first throttle passage 104 that connects the pressure chamber 103 and the intermediate chamber 105, and a second throttle passage 108 that connects the intermediate chamber 105 and the common passage 109. The resistance applied to the liquid passing through the first throttle passage 104 is greater than the resistance applied to the liquid passing through the second throttle passage 108.

[0123] With such a configuration, the length of the second throttle passage 108 can be made shorter than that of the first throttle passage 104, and thus the liquid ejection head 10 can be miniaturized. In addition, the flow path resistance to the circulation of the liquid in the entire flow path of the liquid ejection head 10 can be reduced, and the circulation flow rate of the liquid can be stably increased.

[0124] According to the liquid ejection head 10 according to the embodiment of the present disclosure, a convex portion 115 that protrudes opposite to the first partition wall 118 that separates the pressure chamber 103 and the intermediate chamber 105 is provided between the first damper 106 and the first wall body 114.

[0125] With such a configuration, when the vibration plate 13 is joined to the flow path plate 12 during the manufacture of the liquid ejection head 10, the vibration plate 13 can be firmly joined to the flow path plate 12 by physically pushing the convex portion 115 from the positive side in the Z-axis direction.

[0126] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the thickness of the first damper 106 is 5 μm or less, and the length of the first damper 106 along the longitudinal direction of the intermediate chamber 105 is 200 μm or more. Further, according to the liquid ejection head 10 according to the embodiment of the present disclosure, the intermediate chamber 105 has a second damper 107 at a position facing the first damper 106. Further, according to the liquid ejection head 10 according to the embodiment of the present disclosure, the second damper 107 has a natural frequency different from that of the first damper 106.

[0127] With such a configuration, resonance of the liquid occurs in the system of the nozzle 101, the pressure chamber 103, the first throttle flow path 104, and the intermediate chamber 105 to realize a relatively short resonance period, and the pressure applied to the liquid in the pressure chamber 103 during liquid ejection can be more effectively attenuated in the intermediate chamber 105. With such a configuration, the robustness against the viscosity or flow rate of the liquid can be improved, so that, for example, even for ink with high viscosity or the like, small droplets can be ejected using a short resonance period, and the effect of further suppressing crosstalk can be improved.

[0128] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the common flow path has a third damper 110. With such a configuration, the pressure that could not be completely attenuated by the time it reached the second throttle flow path 108 can be effectively attenuated in the common flow path 109.

[0129] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the thickness of the third damper is larger than that of the first damper, and the length along the longitudinal direction of the third damper is 5 times or more the length along the longitudinal direction of the first damper. With such a configuration, the pressure that could not be completely attenuated by the time it reached the second throttle flow path 108 can be more effectively attenuated in the common flow path 109.

[0130] According to the liquid ejection head 10 according to an embodiment of the present disclosure, the minimum diameter of the nozzle is 15 μm or more, and the volume of the liquid droplets ejected from the nozzle is 2.5 pL or less. Alternatively, according to the liquid ejection head 10 according to an embodiment of the present disclosure, the minimum diameter of the nozzle is 12 μm or more, and the volume of the liquid droplets ejected from the nozzle is 1.5 pL or less. Thus, the liquid ejection head 10 can achieve both an increase in the diameter of the nozzle 101 and a reduction in the size of the ejected liquid droplets.

[0131] According to the liquid ejection head 10 according to an embodiment of the present disclosure, the common flow path 109, the throttle flow path 116, and the intermediate chamber 105 are provided one each on the upstream side and the downstream side in the liquid flow direction as viewed from the pressure chamber 103. With such a configuration, it can be applied to a printing apparatus that circulates and uses liquid.

[0132] According to the liquid ejection head 10 according to an embodiment of the present disclosure, the volume of the intermediate chamber 105 is different between the upstream side and the downstream side in the liquid flow direction. With such a configuration, the period of Helmholtz resonance that can occur in the system among the intermediate chamber 105, the second throttle flow path 108, and the common flow path 109 can be shifted on each of the upstream side and the downstream side, and crosstalk that can be caused by the resonance occurring in the system can be reduced. Note that, in order to shift the resonance period, the volume of the second throttle flow path 108 may be configured to be different between the upstream side and the downstream side instead of the volume of the intermediate chamber 105.

[0133] According to the liquid ejection head 10 according to an embodiment of the present disclosure, the intermediate chamber 105 has first dampers 106 each having different lengths along the flow direction between the upstream side and the downstream side. With such a configuration, the vibration period of the first damper 106 can be shifted between the upstream side and the downstream side. For example, when ejecting liquid at a high frequency, the vibration of the first damper 106 itself and the ejection timing may overlap with each other, causing the ejection state to fluctuate. However, by shifting the vibration period of the first damper 106 on each of the upstream side and the downstream side, the influence on ejection caused by the first damper 106 itself can be suppressed.

[0134] According to the liquid ejection head 10 according to the embodiment of the present disclosure, the position of the nozzle 101 in the flow direction is displaced upstream or downstream from the center of the pressure chamber 103 in the liquid flow direction, and the length of the first damper 106 closer to the nozzle 101 in the flow direction is shorter than the length of the first damper 106 farther from the nozzle 101. Since the pressure of the liquid is absorbed by the silo 102, the first damper 106 closer to the nozzle 101 makes it difficult for the pressure fluctuation in the pressure chamber 103 to be transmitted to the intermediate chamber 105. Therefore, since the required pressure absorption amount of the first damper 106 closer to the nozzle 101 is small, by making it shorter than the first damper 106 on the far side, the minimum required dampers can be arranged on each of the upstream side and the downstream side, and the effect of reducing the size of the liquid ejection head 10 can be obtained.

[0135] The printing apparatus 200 according to the embodiment of the present disclosure includes the liquid ejection head 10 described above, a stage 220 (moving mechanism) that relatively moves the printing target 300 with respect to the liquid ejection head 10, and a control unit 230 that controls the liquid ejection head 10 and the stage 220.

[0136] With such a configuration, it is possible to provide a printing apparatus 200 using the liquid ejection head 10 that can achieve both miniaturization of the ejection droplets and suppression of crosstalk while making the nozzle 101 as large in diameter as possible and increasing the ejection speed as much as possible.

Industrial Applicability

[0137] The present disclosure is useful for a liquid ejection head for high-definition printing.

Explanation of Signs

[0138] 10 Liquid ejection head 101 Nozzle 102 Silo 103 Pressure chamber 104 First throttle flow path 105 Intermediate chamber 106 First damper 107 Second damper 108 Second throttle passage 109 Common passage 110 Third damper 111 Filter 112 Piezoelectric element 113 Pressure receiving part 114 First wall body 115 Convex part 116 Throttle passage 117 Thin part 118 First partition wall 11 Nozzle plate 12 Flow path plate 121 First laminate 122 Second laminate 123 Third laminate 124 Fourth laminate 125 Fifth laminate 126 Sixth laminate 127 Seventh laminate 13 Vibration plate 14 Housing 15 Pressure fluctuation part 200 Printing device 210 Liquid tank 220 Stage (moving mechanism) 230 Control unit 300 Object to be printed

Claims

1. A pressure chamber connected to a nozzle for discharging a liquid, A common flow path for supplying the liquid to the pressure chamber, An intermediate chamber disposed between the pressure chamber and the common flow path and connected to the pressure chamber and the common flow path by throttle flow paths respectively, Comprising, The volume of the intermediate chamber is larger than the volume of the pressure chamber, A liquid discharge head.

2. The volume of the intermediate chamber is at least twice the volume of the pressure chamber, The liquid discharge head according to claim 1.

3. The intermediate chamber has a first damper, The thickness of the first damper is 5 μm or less, The length of the first damper along the longitudinal direction of the intermediate chamber is 200 μm or more, The liquid discharge head according to claim 1.

4. The first damper is integrally formed with a first wall of the pressure chamber connected to a pressure receiving portion that changes the volume of the pressure chamber, The liquid discharge head according to claim 3.

5. The throttle flow path has a first throttle flow path connecting the pressure chamber and the intermediate chamber and a second throttle flow path connecting the intermediate chamber and the common flow path, The fluid resistance of the first throttle flow path is greater than the fluid resistance of the second throttle flow path, The liquid discharge head according to claim 1.

6. A convex portion protruding to face a first partition wall separating the pressure chamber and the intermediate chamber is provided between the first damper and the first wall, The liquid discharge head according to claim 4.

7. The intermediate chamber has a second damper at a position facing the first damper, The second damper has a natural vibration frequency different from that of the first damper, The liquid discharge head according to claim 3.

8. The common flow path has a third damper, The thickness of the third damper is greater than that of the first damper, The length of the third damper along its longitudinal direction is at least five times the length of the first damper along its longitudinal direction, The liquid discharge head according to claim 3.

9. The minimum diameter of the nozzle is 15 μm or more, and the volume of the liquid droplet discharged from the nozzle is 2.5 pL or less, The liquid discharge head according to claim 1.

10. The minimum diameter of the nozzle is 12 μm or more, and the volume of the liquid droplet discharged from the nozzle is 1.5 pL or less, The liquid discharge head according to claim 1.

11. The common flow path, the throttle flow path, and the intermediate chamber are each provided one on the upstream side and one on the downstream side in the flow direction of the liquid as viewed from the pressure chamber. The liquid ejection head according to claim 1.

12. The volume of the intermediate chamber is different between the upstream side and the downstream side. The liquid ejection head according to claim 11.

13. The intermediate chamber has first dampers respectively having different lengths along the flow direction between the upstream side and the downstream side. The liquid ejection head according to claim 11.

14. The position of the nozzle in the flow direction is displaced from the center of the pressure chamber in the flow direction of the liquid to the upstream side or the downstream side, The length of the first damper closer to the nozzle in the flow direction is shorter than the length of the first damper farther from the nozzle. The liquid ejection head according to claim 13.

15. The liquid ejection head according to any one of claims 1 to 14, a moving mechanism that relatively moves a printing material with respect to the liquid ejection head, a control unit that controls the liquid ejection head and the moving mechanism, A printing apparatus comprising:

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