Liquid discharge head and liquid discharge apparatus

Abstract

This invention provides a liquid nozzle and a liquid ejection device for suppressing the continuous thickening development in a common flow channel. The liquid nozzle of this invention is characterized by comprising: a plurality of independent flow channels corresponding to a plurality of nozzles for ejecting liquid and arranged along a first direction; a first common flow channel communicating with one side of the plurality of independent flow channels; a second common flow channel communicating with the other side of the plurality of independent flow channels; a first flow channel communicating with the first common flow channel and supplying liquid to the first common flow channel; a second flow channel communicating with the first common flow channel at a side relative to the first flow channel in the first direction and recovering liquid from the first common flow channel; a third flow channel communicating with the second common flow channel and supplying liquid to the second common flow channel; and a fourth flow channel communicating with the second common flow channel at a side relative to the third flow channel in the first direction and recovering liquid from the second common flow channel.

Description

Technical Field

[0001] This invention relates to a liquid ejector head and a liquid ejection device. Background Technology

[0002] In liquid ejector heads installed in liquid ejection devices such as inkjet printers and ejecting liquids such as ink, a technique for circulating liquid within flow channels in the liquid ejector head has been proposed to prevent the retention of air bubbles or thickening of the liquid inside the liquid ejector head. For example, Patent Document 1 describes a technique related to a liquid ejector head having: multiple independent flow channels corresponding to multiple nozzles; a common supply flow channel connected to one side of the multiple independent flow channels; a common recovery flow channel connected to the other side of the multiple independent flow channels; two supply ports for supplying liquid to the common supply flow channel; and two recovery ports for recovering liquid from the common recovery flow channel. In this liquid ejector head, liquid supplied from the two supply ports to the multiple independent flow channels via the common supply flow channel is recovered from the two recovery ports via the common recovery flow channel.

[0003] However, in existing technologies, because independent flow channels have higher flow resistance compared to common supply channels, the independent flow channel becomes the limiting factor for ink flow within the overall system of common supply channels, independent flow channels, and common recovery channels. Consequently, in common supply channels or common recovery channels where the flow resistance is lower than that of independent flow channels, the ink flow rate may be less than assumed. This prevents the proper recovery of thickened ink or the supply of non-thickened ink, resulting in the continuous thickening process.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-199695 Summary of the Invention

[0005] To address the above problems, the liquid ejector head of the present invention is characterized by comprising: a plurality of independent flow channels corresponding to a plurality of nozzles for ejecting liquid and arranged along a first direction; a first common flow channel communicating with one side of the plurality of independent flow channels; a second common flow channel communicating with the other side of the plurality of independent flow channels; a first flow channel communicating with the first common flow channel and supplying liquid to the first common flow channel; a second flow channel communicating with the first common flow channel on one side relative to the first flow channel in the first direction and recovering liquid from the first common flow channel; a third flow channel communicating with the second common flow channel and supplying liquid to the second common flow channel; and a fourth flow channel communicating with the second common flow channel on the other side relative to the third flow channel in the first direction and recovering liquid from the second common flow channel.

[0006] Furthermore, the liquid ejection device according to the present invention is characterized by comprising: the liquid ejection head described above; and a control device that controls a pressure regulating device to control the ejection of liquid from the liquid ejection head, wherein the pressure regulating device regulates the pressure in the first flow channel, the pressure in the second flow channel, the pressure in the third flow channel, and the pressure in the fourth flow channel. Attached Figure Description

[0007] Figure 1 This is a structural diagram illustrating an example of a liquid ejection device 100 according to an embodiment of the present invention.

[0008] Figure 2 An explanatory diagram showing an example of the structure of the ink supply device 8.

[0009] Figure 3 An exploded perspective view showing an example of the structure of a liquid ejector head 1.

[0010] Figure 4 A cross-sectional view showing an example of the structure of a liquid ejector head 1.

[0011] Figure 5 A cross-sectional view showing an example of the structure of a liquid ejector head 1.

[0012] Figure 6 A top view showing an example of the structure of a liquid ejector head 1.

[0013] Figure 7 An illustrative diagram showing an example of the pressure of ink inside a liquid ejector head 1.

[0014] Figure 8 A top view showing an example of the structure of the liquid ejector head 1B involved in Modified Example 1.

[0015] Figure 9 A top view showing an example of the structure of the liquid ejector head 1C involved in Modified Example 2.

[0016] Figure 10 A top view showing an example of the structure of the liquid ejector head 1D involved in Modified Example 2. Detailed Implementation

[0017] Hereinafter, the methods for implementing the present invention will be described with reference to the accompanying drawings. However, the dimensions and scales of the various parts in the drawings differ appropriately from the actual situation. Furthermore, although various technical preferences have been added since the embodiments described below are preferred examples of the present invention, the scope of the present invention is not limited to these embodiments unless otherwise specifically limited in the following description.

[0018] A. Implementation Method

[0019] The liquid ejection device 100 according to this embodiment will be described below.

[0020] 1. Overview of the liquid ejection device

[0021] Figure 1 The diagram shows the liquid ejection device 100 according to this embodiment.

[0022] The liquid ejection device 100 is an inkjet printing device that ejects ink onto a PP medium. Although the PP medium is typically printing paper, any printing material such as resin film or fabric can also be used as the PP medium. Furthermore, the ink is an example of a "liquid".

[0023] The liquid ejection device 100 includes: multiple liquid ejection heads 1, a control device 7, an ink supply device 8, a moving mechanism 91, and a conveying mechanism 92.

[0024] The control device 7 includes processing circuits such as a CPU or FPGA, and storage circuits such as semiconductor memory, and controls various elements of the liquid dispensing device 100. Here, CPU stands for Central Processing Unit, and FPGA stands for Field Programmable Gate Array.

[0025] Under the control of the control device 7, the moving mechanism 91 transports the medium PP in the Y1 direction along the Y-axis. Hereinafter, the Y1 direction along the Y-axis and the Y2 direction opposite to the Y1 direction are collectively referred to as the Y-axis direction. Similarly, the X1 direction along the X-axis (which intersects the Y-axis) and the X2 direction opposite to the X1 direction are collectively referred to as the X-axis direction. Furthermore, the Z1 direction along the Z-axis (which intersects both the X-axis and Y-axis) and the Z2 direction opposite to the Z1 direction are collectively referred to as the Z-axis direction. Additionally, in the following text, if the dot product of a vector with one object as the starting point and another object as the ending point, and a vector pointing towards the X1 direction, is positive, it is said that with one object as the reference, the other object exists on the "X1 side". Furthermore, in the following text, if the dot product of a vector with one object as the starting point and another object as the ending point, and a vector pointing towards the X2 direction, is positive, it is said that with one object as the reference, the other object exists on the "X2 side". The same applies to the Y1 side, Y2 side, Z1 side, and Z2 side.

[0026] In this embodiment, as an example, it is assumed that the X-axis, Y-axis, and Z-axis are mutually orthogonal. However, the present invention is not limited to this arrangement. It is permissible as long as the X-axis, Y-axis, and Z-axis intersect each other.

[0027] Under the control of the control device 7, the conveying mechanism 92 causes multiple liquid nozzles 1 to reciprocate in the X1 and X2 directions. The conveying mechanism 92 includes a housing 921 for storing the multiple liquid nozzles 1 and a seamless strap 922 for fixing the housing 921. Alternatively, the liquid container 93 can be stored together with the liquid nozzles 1 in the housing 921.

[0028] The control device 7 supplies a drive signal Com for driving the liquid ejector head 1 and a control signal SI for controlling the liquid ejector head 1. Then, under the control of the control signal SI, the liquid ejector head 1 is driven by the drive signal Com, causing ink to be ejected from some or all of the plurality of nozzles N provided in the liquid ejector head 1 in the Z1 direction. That is, the liquid ejector head 1 ejects ink from some or all of the plurality of nozzles N in a manner linked to the transport of the medium PP implemented by the moving mechanism 91 and the reciprocating motion of the liquid ejector head 1 implemented by the transport mechanism 92, and the ejected ink is sprayed onto the surface of the medium PP, thereby forming a desired image on the surface of the medium PP. Furthermore, regarding the nozzles N, [further details will be provided]. Figure 3 as well as Figure 4 The narrative will be presented in the text.

[0029] The ink supply device 8 stores ink. Furthermore, based on a control signal Ctr supplied from the control device 7, the ink supply device 8 supplies the stored ink to the liquid nozzle 1. Additionally, based on the control signal Ctr supplied from the control device 7, the ink supply device 8 recovers ink from the liquid nozzle 1 and returns the recovered ink to the liquid nozzle 1.

[0030] Furthermore, in this embodiment, as an example, it is assumed that the ink supply device 8 stores four types of ink corresponding to blue-green, magenta, yellow, and black. Also, in this embodiment, as an example, it is assumed that the liquid nozzle 1 has four liquid nozzles 1 corresponding to the four types of ink. However, for the sake of simplicity, the following description will focus on one type of ink among the four types stored in the ink supply device 8. Furthermore, for the sake of simplicity, the following description will focus on one liquid nozzle 1 among the four liquid nozzles 1 of the liquid nozzle 1, corresponding to only one type of ink.

[0031] 2. Overview of the ink supply system

[0032] The following is in reference Figure 2 At the same time, an overview of the ink supply device 8 will be provided.

[0033] Figure 2 This is an explanatory diagram used to illustrate the ink supply device 8.

[0034] like Figure 2 As shown, the ink supply device 8 includes: an ink storage container 81, an ink supply container 82, a pump G0, and a pressure regulating device 83.

[0035] The ink storage container 81 is a container for storing ink. For example, the ink storage container 81 can be a cartridge that can be detached from the liquid dispensing device 100, a bag-shaped ink bag formed of a flexible film, or an ink can that can be refilled with ink.

[0036] Pump G0 is a pump that supplies ink stored in ink storage container 81 to ink supply container 82 based on control signal Ctr supplied from control device 7.

[0037] The ink supply container 82 is a container for temporarily storing ink supplied from the ink storage container 81 and ink recovered from the liquid ejector head 1.

[0038] The pressure regulating device 83 includes pumps G11, G12, G21 and G22.

[0039] Pump G11 supplies ink stored in ink supply container 82 to liquid nozzle 1 via circulation channel J11 based on control signal Ctr supplied from control device 7. Here, circulation channel J11 is connected to connection port H11 provided on liquid nozzle 1. Pump G11 supplies ink to liquid nozzle 1 via circulation channel J11 and connection port H11.

[0040] Pump G12, based on a control signal Ctr supplied from control device 7, recovers ink from liquid nozzle 1 via circulation channel J12 and supplies the recovered ink to ink supply container 82. Here, circulation channel J12 is connected to connection port H12 provided on liquid nozzle 1. Pump G12 recovers ink from liquid nozzle 1 via circulation channel J12 and connection port H12.

[0041] Pump G21, based on a control signal Ctr supplied from control device 7, recovers ink from liquid nozzle 1 via circulation channel J21 and supplies the recovered ink to ink supply container 82. Here, circulation channel J21 is connected to connection port H21 provided on liquid nozzle 1. Pump G21 recovers ink from liquid nozzle 1 via circulation channel J21 and connection port H21.

[0042] Pump G22 supplies ink stored in ink supply container 82 to liquid nozzle 1 via circulation channel J22 based on control signal Ctr supplied from control device 7. Here, circulation channel J22 is connected to connection port H22 provided on liquid nozzle 1. Pump G22 supplies ink to liquid nozzle 1 via circulation channel J22 and connection port H22.

[0043] Additionally, although the illustration is omitted, a pressure estimation device can be provided in the ink supply device 8. This pressure estimation device estimates the pressure applied to the ink in circulation channel J11, the pressure applied to the ink in circulation channel J12, the pressure applied to the ink in circulation channel J21, and the pressure applied to the ink in circulation channel J22. This pressure estimation device can consist of sensors that detect the pressure applied to the ink in circulation channel J11, J12, J21, and J22. Furthermore, the pressure estimation device can be a computing device that estimates the pressure applied to the ink in the circulation channel J11, the ink in the circulation channel J12, the ink in the circulation channel J21, and the ink in the circulation channel J22 based on the operating conditions of pump G11, pump G12, pump G21, and pump G22.

[0044] In addition, in this embodiment, the circulating channel J11 is an example of a "first channel", the circulating channel J12 is an example of a "second channel", the circulating channel J22 is an example of a "third channel", and the circulating channel J21 is an example of a "fourth channel".

[0045] 3. Overview of the liquid nozzle

[0046] The following is in reference Figures 3 to 5 At the same time, a summary of the liquid ejector head 1 will be provided.

[0047] Figure 3 This is an exploded perspective view of liquid ejector head 1. Figure 4 for Figure 3 The sectional view along line II-II in the middle. Figure 5 for Figure 3 A sectional view along line III-III.

[0048] like Figures 3 to 5 As shown, the liquid ejector head 1 includes: a nozzle substrate 21, plastic sheets CS1 and CS2, a connecting plate 22, a pressure chamber substrate 23, a vibrating plate 24, a sealing substrate 25, a flow channel forming substrate 26, and a wiring substrate 4.

[0049] like Figure 3As shown, the nozzle substrate 21 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. Here, "substantially parallel" means, in addition to the case of perfect parallelism, that it can also be considered parallel if errors are taken into account. In this embodiment, "substantially parallel" means that it is defined as including the case where parallelism is considered if an error of about 10% is taken into account. Although the nozzle substrate 21 is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing techniques such as etching, known materials and manufacturing methods can be used arbitrarily in the manufacture of the nozzle substrate 21.

[0050] M nozzles N are formed on the nozzle substrate 21. Here, nozzle N refers to a through hole provided on the nozzle substrate 21. Furthermore, the value M is a natural number that satisfies M≥2. In this embodiment, it is assumed that the M nozzles N are arranged on the nozzle substrate 21 in a manner extending in the Y-axis direction. In the following text, the M nozzles N extending in the Y-axis direction will sometimes be referred to as nozzle row Ln.

[0051] like Figures 3 to 5 As shown, a connecting plate 22 is provided at a position on the Z2 side, with the nozzle substrate 21 as a reference. The connecting plate 22 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. Although the connecting plate 22 can be manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology, any known materials and manufacturing methods can be used in the manufacturing of the connecting plate 22.

[0052] Ink channels are formed on the connecting plate 22.

[0053] Specifically, on the connecting plate 22, a common flow channel BB1 extending in the Y-axis direction is formed, and a common flow channel BB2 extending in the Y-axis direction at a position on the X2 side based on the common flow channel BB1. Furthermore, on the connecting plate 22, a common flow channel BA1 extending in the Y-axis direction is formed at a position between the common flow channels BB1 and BB2, and a common flow channel BA2 extending in the Y-axis direction is formed at a position between the common flow channels BA1 and BB2.

[0054] Furthermore, on the connecting plate 22, there are M connecting channels BK1 corresponding to M nozzles N, M connecting channels BK2 corresponding to M nozzles N, M connecting channels BR1 corresponding to M nozzles N, M connecting channels BR2 corresponding to M nozzles N, and M nozzle channels BN corresponding to M nozzles N.

[0055] Specifically, connecting flow channel BK1 is configured to communicate with common flow channel BA1 and extend in the Z-axis direction at a position on the X2 side and a position on the Z2 side, with common flow channel BA1 as the reference. Connecting flow channel BR1 is configured to extend in the Z-axis direction at a position on the X2 side, with connecting flow channel BK1 as the reference. Connecting flow channel BK2 is configured to communicate with common flow channel BA2 and extend in the Z-axis direction at a position on the X1 side and a position on the Z2 side, with common flow channel BA2 as the reference. Connecting flow channel BR2 is configured to extend in the Z-axis direction at a position on the X2 side and a position on the X1 side, with connecting flow channel BR1 as the reference. Nozzle flow channel BN is located between connecting flow channels BR1 and BR2, communicating with both connecting flow channels BR1 and BR2, and also communicating with nozzle N corresponding to nozzle flow channel BN.

[0056] Additionally, in the following text, common flow channels BA1 and BA2 will sometimes be referred to as common flow channel BA, common flow channels BB1 and BB2 will be referred to as common flow channel BB, connecting flow channels BK1 and BK2 will be referred to as connecting flow channel BK, and connecting flow channels BR1 and BR2 will be referred to as connecting flow channel BR.

[0057] like Figures 3 to 5 As shown, a pressure chamber substrate 23 is provided at a position on the Z2 side, with the connecting plate 22 as a reference. The pressure chamber substrate 23 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. Although the pressure chamber substrate 23 can be manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology, any known materials and manufacturing methods can be used in the manufacture of the pressure chamber substrate 23.

[0058] Ink flow channels are formed on the pressure chamber substrate 23. Specifically, M pressure chambers CV1 corresponding to M nozzles N and M pressure chambers CV2 corresponding to M nozzles N are formed on the pressure chamber substrate 23. Pressure chamber CV1 is configured to extend in the X-axis direction at a position on the Z2 side relative to connecting flow channel BK1 and at a position on the Z2 side relative to connecting flow channel BR1, and communicates with connecting flow channel BK1 and connecting flow channel BR1. Pressure chamber CV2 is configured to extend in the X-axis direction at a position on the Z2 side relative to connecting flow channel BK2 and at a position on the Z2 side relative to connecting flow channel BR2, and communicates with connecting flow channel BK2 and connecting flow channel BR2.

[0059] Additionally, in the following text, pressure chambers CV1 and CV2 will sometimes be referred to collectively as pressure chamber CV.

[0060] In the following text, the connecting channel BK1, the pressure chamber CV1 connected to the connecting channel BK1, the connecting channel BR1 connected to the pressure chamber CV1, the nozzle channel BN connected to the connecting channel BR1, the connecting channel BR2 connected to the nozzle channel BN, the pressure chamber CV2 connected to the connecting channel BR2, and the connecting channel BK2 connected to the pressure chamber CV2 are sometimes referred to as independent channels RK. Furthermore, in the following text, the independent channel RK corresponding to the m-th nozzle N among the M nozzles N is sometimes referred to as independent channel RK[m]. Here, the variable m is a natural number that satisfies 1≤m≤M. In this embodiment, the M independent channels RK[1]~RK[M] corresponding to the M nozzles N are arranged along the Y-axis direction.

[0061] Furthermore, in this embodiment, as an example, it is assumed that each of the M independent flow channels RK[1] to RK[M] has approximately the same shape as each other, and each of the M independent flow channels RK[1] to RK[M] has approximately the same size. Here, "approximately the same" means not only the case of being completely identical, but also the case of being considered identical if errors are taken into account. In this embodiment, "approximately the same" means the case of being considered identical if an error of about 10% is taken into account.

[0062] like Figures 3 to 5 As shown, a vibrating plate 24 is provided at a position on the Z2 side, with the pressure chamber substrate 23 as a reference. The vibrating plate 24 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane, and is a component capable of elastic vibration. The vibrating plate 24 has, for example, an elastic membrane made of silicon oxide and an insulating membrane made of zirconium oxide.

[0063] like Figures 3 to 5As shown, at a position on the Z2 side with reference to the vibrating plate 24, there are M piezoelectric elements PZ1 corresponding to M pressure chambers CV1 and M piezoelectric elements PZ2 corresponding to M pressure chambers CV2. In the following text, piezoelectric elements PZ1 and PZ2 will sometimes be collectively referred to as piezoelectric element PZ. The piezoelectric element PZ is a passive element that deforms according to the potential change of the drive signal Com. Specifically, the piezoelectric element PZ is driven to deform according to the potential change of the drive signal Com. The vibrating plate 24 vibrates in a manner linked to the deformation of the piezoelectric element PZ. When the vibrating plate 24 vibrates, the pressure inside the pressure chambers CV changes. Furthermore, due to the pressure change inside the pressure chambers CV, the ink filled inside the pressure chambers CV is ejected from the nozzle N through the connecting flow channel BR and the nozzle flow channel BN.

[0064] like Figures 3 to 5 As shown, a sealing substrate 25 is provided at a position on the Z2 side, with reference to the pressure chamber substrate 23, to protect M piezoelectric elements PZ1 and M piezoelectric elements PZ2. The sealing substrate 25 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. Although the sealing substrate 25 can be manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology, any known materials and manufacturing methods can be used in the manufacture of the sealing substrate 25.

[0065] On the Z1 side of one of the two surfaces of the sealing substrate 25 with the Z-axis as the normal direction, there are recesses for covering M piezoelectric elements PZ1 and M piezoelectric elements PZ2. In the following text, the sealing space covering the M piezoelectric elements PZ1 and formed between the vibrating plate 24 and the sealing substrate 25 is referred to as sealing space SP1, and the sealing space covering the M piezoelectric elements PZ2 and formed between the vibrating plate 24 and the sealing substrate 25 is referred to as sealing space SP2. Furthermore, in the following text, sealing space SP1 and sealing space SP2 are sometimes collectively referred to as sealing space SP. Sealing space SP is a space that seals the piezoelectric elements PZ to prevent them from deteriorating due to moisture or other factors.

[0066] A through hole 250 is provided on the sealing substrate 25. The through hole 250 is located between the sealing space SP1 and the sealing space SP2 when the sealing substrate 25 is viewed in the Z1 direction, and extends from the Z1 side surface of the sealing substrate 25 to the Z2 side surface of the sealing substrate 25. A wiring substrate 4 is inserted through the through hole 250.

[0067] like Figures 3 to 5As shown, a flow channel forming substrate 26 is provided at a position on the Z2 side, with reference to the connecting plate 22. The flow channel forming substrate 26 is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. Although the flow channel forming substrate 26 can be formed, for example, by injection molding of a resin material, any known materials and manufacturing methods can be used in the manufacture of the flow channel forming substrate 26.

[0068] Ink-filled channels are formed on the channel forming substrate 26.

[0069] Specifically, a common flow channel BC1 and a common flow channel BC2 extending in the Y-axis direction are formed on the flow channel forming substrate 26. Common flow channel BC1 communicates with common flow channel BB1 and is located at a position on the Z2 side with reference to common flow channel BB1. Common flow channel BC2 communicates with common flow channel BB2 and is located at a position on the Z2 side with reference to common flow channel BB2 and at a position on the X2 side with reference to common flow channel BC1. In the following text, common flow channel BC1 and common flow channel BC2 will sometimes be collectively referred to as common flow channel BC.

[0070] In the following text, the common flow channel BA1, the common flow channel BB1 connected to the common flow channel BA1, and the common flow channel BC1 connected to the common flow channel BB1 will sometimes be referred to as the common flow channel R1. Furthermore, in the following text, the common flow channel BA2, the common flow channel BB2 connected to the common flow channel BA2, and the common flow channel BC2 connected to the common flow channel BB2 will sometimes be referred to as the common flow channel R2. Additionally, in the following text, the common flow channels R1 and R2 will sometimes be collectively referred to as the common flow channel R. Furthermore, common flow channel R1 is an example of a "first common flow channel," and common flow channel R2 is an example of a "second common flow channel."

[0071] The flow channel forming substrate 26 is provided with a connection port H11 communicating with a common flow channel BC1, a connection port H12 communicating with a common flow channel BC1, a connection port H21 communicating with a common flow channel BC2, and a connection port H22 communicating with a common flow channel BC2.

[0072] Furthermore, in the common flow channel R1, including the common flow channel BC1, ink is supplied from the ink supply container 82 via the circulation flow channel J11 and the connection port H11. A portion of the ink stored in the common flow channel R1 is recovered into the ink supply container 82 via the circulation flow channel J12 and the connection port H12. Additionally, in the common flow channel R2, including the common flow channel BC2, ink is supplied from the ink supply container 82 via the circulation flow channel J22 and the connection port H22. A portion of the ink stored in the common flow channel R2 is recovered into the ink supply container 82 via the circulation flow channel J21 and the connection port H21.

[0073] Furthermore, a portion of the ink supplied to the common flow channel R1 is filled into the pressure chamber CV1 via the connecting flow channel BK1. Also, when the piezoelectric element PZ1 is driven by the drive signal Com, a portion of the ink filled into the pressure chamber CV1 is ejected from the nozzle N via the connecting flow channel BR1. Additionally, a portion of the ink supplied to the pressure chamber CV1 is filled into the pressure chamber CV2 via the connecting flow channel BR1, the nozzle flow channel BN, and the connecting flow channel BR2. Furthermore, when the piezoelectric element PZ2 is driven by the drive signal Com, a portion of the ink filled into the pressure chamber CV2 is ejected from the nozzle N via the connecting flow channel BR2.

[0074] A through hole 260 is provided on the flow channel forming substrate 26. The through hole 260 is located between the common flow channel BC1 and the common flow channel BC2 when the flow channel forming substrate 26 is viewed in the Z1 direction, and extends from the Z1 side surface of the flow channel forming substrate 26 to the Z2 side surface of the flow channel forming substrate 26. A wiring substrate 4 is inserted through the through hole 260.

[0075] like Figures 3 to 5 As shown, a wiring board 4 is mounted on the Z2 side of one of the two surfaces of the vibrating plate 24 with the Z-axis as the normal direction. The wiring board 4 is a component for electrically connecting the liquid nozzle 1 to the control device 7. A flexible wiring board, such as an FPC or FFC, is preferably used as the wiring board 4. Here, FPC is short for Flexible Printed Circuit, and FFC is short for Flexible Flat Cable. An integrated circuit 40 is mounted on the wiring board 4. The integrated circuit 40 is a circuit that switches whether a drive signal Com is supplied to the piezoelectric element PZ1 under the control of the control signal SI.

[0076] like Figures 3 to 5As shown, a plastic sheet CS1 is provided at a position on the Z1 side based on the connecting plate 22 and at a position on the X1 side based on the nozzle substrate 21, in a manner that closes the common flow channel BA1 and the common flow channel BB1. Furthermore, a plastic sheet CS2 is provided at a position on the Z1 side based on the connecting plate 22 and at a position on the X2 side based on the nozzle substrate 21, in a manner that closes the common flow channel BA2 and the common flow channel BB2. In the following text, the plastic sheet CS1 and the plastic sheet CS2 will sometimes be collectively referred to as the plastic sheet CS. The plastic sheet CS is a plate-shaped component that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The plastic sheet CS is formed of an elastic material, thereby absorbing pressure variations of the ink within the common flow channel BA and the connecting flow channel BK.

[0077] Additionally, although the illustration is omitted, the liquid ejector head 1 includes a cover for sealing the nozzle surface NP, one of the two surfaces of the nozzle substrate 21 with the Z-axis as the normal direction. During periods when no ink is ejected from the nozzle N, the cover seals the nozzle surface NP of the nozzle substrate 21 on which the nozzle N is formed.

[0078] 4. Ink flow in the liquid ejector head

[0079] The following is in reference Figure 6 as well as Figure 7 At the same time, the flow of ink in the liquid ejector head 1 will be explained.

[0080] Figure 6 This is an explanatory diagram illustrating the flow of ink in the liquid ejector head 1. Specifically, in Figure 6 The diagram shows the ink flow in the common flow channel R and the independent flow channel RK when viewed from above in the Z1 direction towards the liquid ejector head 1. Furthermore, although in Figure 6 And the following description Figures 8 to 10 In the illustration, for ease of depiction, the connecting channel BK is shown as extending in the X-axis direction; however, in the liquid nozzle 1, the connecting channel BK extends in the Z-axis direction. Furthermore, in... Figure 6 And the following description Figures 8 to 10 In the example, the value M is assumed to be "8".

[0081] like Figure 6As shown, circulation channel J11 supplies ink to common channel R1, circulation channel J12 recovers ink from common channel R1, circulation channel J22 supplies ink to common channel R2, and circulation channel J21 recovers ink from common channel R2. Therefore, in common channel R1, as indicated by arrow EA1, the ink flows in the Y1 direction, and in common channel R2, as indicated by arrow EA2, the ink flows in the Y2 direction. Furthermore, in independent channel RK[m], ink is supplied from common channel R1 and recovered from common channel R2. Therefore, in independent channel RK[m], as indicated by arrow FA[m], ink flows from common channel R1 in the X2 direction to common channel R2.

[0082] Figure 7 This is an explanatory diagram illustrating the pressure applied to ink disposed within a flow channel in the liquid ejection device 100.

[0083] like Figure 7 As shown, the control device 7 controls the pressure regulating device 83 of the ink supply device 8 in such a way that the pressure P11 applied to the ink in the circulation channel J11, the pressure P12 applied to the ink in the circulation channel J12, the pressure P21 applied to the ink in the circulation channel J21, and the pressure P22 applied to the ink in the circulation channel J22 satisfy the first pressure condition expressed by the following equations (1) and (2).

[0084] First pressure condition

[0085] P11>P12……Equation (1)

[0086] P22>P21……Equation (2)

[0087] In this embodiment, since pressures P11, P12, P21, and P22 satisfy the first pressure condition, the ink in the common flow channel R1 can be circulated from the circulation channel J11 to the circulation channel J12 as indicated by arrow EA1, and the ink in the common flow channel R2 can be circulated from the circulation channel J22 to the circulation channel J21 as indicated by arrow EA2. Therefore, according to this embodiment, compared with a method in which the ink is not circulated in the common flow channel R, the continuous thickening that develops in the common flow channel R can be suppressed.

[0088] like Figure 7 As shown, the control device 7 controls the pressure regulating device 83 of the ink supply device 8 in such a way that the pressures P11, P12, P21 and P22 satisfy the second pressure conditions expressed by the following equations (3) and (4).

[0089] Second pressure condition

[0090] P11>P21……Equation (3)

[0091] P12>P22……Equation (4)

[0092] In this embodiment, since pressures P11, P12, P21 and P22 satisfy the second pressure condition, ink can be circulated from the common channel R1 through the independent channel RK[m] to the common channel R2 as indicated by arrow FA[m], and ink can be smoothly supplied to the pressure chamber CV provided in the independent channel RK[m].

[0093] like Figure 7 As shown, the control device 7 controls the pressure regulating device 83 of the ink supply device 8 in such a way that the pressures P11, P12, P21 and P22 and the atmospheric pressure PC satisfy the third pressure condition expressed by the following equations (5) and (6).

[0094] Third pressure condition

[0095] |P11-PC|<|P21-PC|……Equation (5)

[0096] |P12-PC|<|P22-PC|……Equation (6)

[0097] In this embodiment, atmospheric pressure PC refers to standard atmospheric pressure, specifically one atmosphere, i.e., 101325 Pascals. However, the invention is not limited to this method. Atmospheric pressure PC can also be the atmospheric pressure of the area where the liquid ejection device 100 is located.

[0098] Furthermore, since pressures P11, P12, P21 and P22 satisfy the second pressure condition and the third pressure condition, the atmospheric pressure correlation condition shown in the following equations (7), (8), (9) and (10) holds between each of pressures P11, P12, P21 and P22 and atmospheric pressure PC.

[0099] Atmospheric pressure correlation conditions

[0100] P11>PC……Equation (7)

[0101] P12>PC……Equation (8)

[0102] PC>P21……Equation (9)

[0103] PC>P22……Equation (10)

[0104] That is, in this embodiment, since pressures P11, P12, P21 and P22 satisfy the atmospheric pressure correlation condition, the third pressure condition described above can also be expressed as the following equations (5A) and (6A).

[0105] Third pressure condition

[0106] P11-PC<PC-P21……Equation (5A)

[0107] P12-PC<PC-P22……Equation (6A)

[0108] Furthermore, in the following text, the pressure applied to the ink near the nozzle N of the nozzle channel BN within the ink in the independent flow channel RK[m] is sometimes referred to as the nozzle near pressure PN[m].

[0109] In this embodiment, since pressures P11, P12, P21, and P22 satisfy the third pressure condition, the pressure PN[m] near the nozzle can be set to a pressure lower than atmospheric pressure PC. Furthermore, since the pressure PN[m] near the nozzle is set to a pressure lower than atmospheric pressure PC in this embodiment, ink leakage from the nozzle N can be suppressed, except in cases where ink in the pressure chamber CV is ejected from the nozzle N due to the drive of the piezoelectric element PZ.

[0110] like Figure 7 As shown, the control device 7 controls the pressure regulating device 83 of the ink supply device 8 in such a way that the pressures P11, P12, P21 and P22 satisfy the fourth pressure condition expressed by the following formula (11).

[0111] Fourth pressure condition

[0112] P11+P21=P12+P22……Equation (11)

[0113] Furthermore, for the fourth pressure condition, it is assumed that in addition to the cases where the sum of pressure P11 and pressure P21 and the sum of pressure P12 and pressure P22 are exactly the same, it also includes the cases where the sum of pressure P11 and pressure P21 and the sum of pressure P12 and pressure P22 are approximately the same.

[0114] Furthermore, in the following text, the pressure on the ink in the connection portion with the independent flow channel RK[m] of the ink applied in the common flow channel R1 is referred to as the independent flow channel near pressure PR1[m], and the pressure on the ink in the connection portion with the independent flow channel RK[m] of the ink applied in the common flow channel R2 is referred to as the independent flow channel near pressure PR2[m]. In this embodiment, as an example, it is assumed that the nozzle near pressure PN[m] can be expressed using the independent flow channel near pressure PR1[m] and the independent flow channel near pressure PR2[m] according to the following formula (12).

[0115] PN[m]={PR1[m]+PR2[m]}÷2……Equation (12)

[0116] In this embodiment, since pressures P11, P12, P21, and P22 satisfy the fourth pressure condition, the pressures PN[1] to PN[M] near the nozzles corresponding to the M independent flow channels RK[1] to RK[M] can be set to approximately the same value. More specifically, when the pressure PN[m] near the nozzle satisfies the above-described equation (12) as in this embodiment, the pressures PN[1] to PN[M] near the nozzle respectively satisfy the nozzle pressure condition shown in the following equation (15) using the average pressure PM1 of pressure P11 and pressure P21 shown in the following equation (13), and the average pressure PM2 of pressure P12 and pressure P22 shown in the following equation (14).

[0117] Nozzle pressure conditions

[0118] PM1={P11+P21}÷2……Equation (13)

[0119] PM2={P12+P22}÷2……Equation (14)

[0120] PN[m]=PM1=PM2……Equation (15)

[0121] Furthermore, although the nozzle pressure condition is defined by equation (15) above in this embodiment, the present invention is not limited to this method. The nozzle pressure condition can also be defined by, for example, the following equation (16).

[0122] Nozzle pressure conditions

[0123] PN[m]={P11+P12+P21+P22}÷4……Equation (16)

[0124] Thus, according to this embodiment, since the M nozzles N corresponding to the M independent flow channels RK[1] to RK[M] can eject ink while satisfying the nozzle pressure conditions, compared with the method where the pressures PN[1] to PN[M] near the M nozzles are different from each other, the deviation of the ink ejection characteristics from the M nozzles N corresponding to the M independent flow channels RK[1] to RK[M] can be reduced.

[0125] In addition, such as Figure 6 As shown, in this embodiment, the circulating channel J11 communicates with the common channel R1 at its end on the Y2 side in the Y-axis direction, and the circulating channel J12 communicates with the common channel R1 at its end on the Y1 side in the Y-axis direction. Therefore, in this embodiment, compared to, for example, the circulating channel J11 communicating with the common channel R1 at its central portion in the Y-axis direction, and the circulating channel J12 communicating with the common channel R1 at its central portion in the Y-axis direction, the continuous thickening development in the common channel R1 can be suppressed. Furthermore, in this embodiment, the Y-axis direction, i.e., the Y1 direction and the Y2 direction, is an example of a "first direction," the Y1 side is an example of "one side in the first direction," and the Y2 side is an example of "the other side in the first direction."

[0126] In addition, such as Figure 6 As shown, in this embodiment, the circulating channel J21 is connected to the common channel R2 at its Y2-side end in the Y-axis direction, and the circulating channel J22 is connected to the common channel R2 at its Y1-side end in the Y-axis direction. Therefore, in this embodiment, compared to, for example, the circulating channel J21 being connected to the common channel R2 at its central portion in the Y-axis direction, and the circulating channel J22 being connected to the common channel R2 at its central portion in the Y-axis direction, the continuous thickening development in the common channel R2 can be suppressed.

[0127] 5. Summary of Implementation Methods

[0128] As explained above, the liquid ejector head 1 according to this embodiment is characterized by comprising: M independent flow channels RK, which correspond to M nozzles N and are arranged along the Y-axis direction; a common flow channel R1, which is connected to one side of the M independent flow channels RK; a common flow channel R2, which is connected to the other side of the M independent flow channels RK; a circulation flow channel J11, which is connected to the common flow channel R1 and supplies ink to the common flow channel R1; a circulation flow channel J12, which is connected to the common flow channel R1 on the Y1 side compared to the circulation flow channel J11 and recovers ink from the common flow channel R1; a circulation flow channel J22, which is connected to the common flow channel R2 and supplies ink to the common flow channel R2; and a circulation flow channel J21, which is connected to the common flow channel R2 on the Y2 side compared to the circulation flow channel J22 and recovers ink from the common flow channel R2.

[0129] Thus, according to this embodiment, ink can be circulated from circulation channel J11 to circulation channel J12 within the common channel R1, and ink can be circulated from circulation channel J22 to circulation channel J21 within the common channel R2. Therefore, according to this embodiment, compared to, for example, a cavity circulation where common channel R1 is only connected to circulation channel J11 and common channel R2 is only connected to circulation channel J21, and ink supplied from circulation channel J11 to common channel R1 is recovered from circulation channel J21 via independent channels RK and common channel R2, the continuous development of thickening within common channels R1 and common channel R2 can be suppressed.

[0130] Furthermore, according to this embodiment, in the common flow channel R1, the ink flows from the Y2 side to the Y1 side in the Y1 direction, and in the common flow channel R2, the ink flows from the Y1 side to the Y2 side in the Y2 direction. Therefore, according to this embodiment, compared to a method where, for example, the flow direction of the ink in the common flow channel R1 and the flow direction of the ink in the common flow channel R2 are the same, the deviation in pressure applied to the ink near the M nozzles N corresponding to the M independent flow channels RK can be reduced, thereby reducing the deviation in the ejection characteristics of the ink from the M nozzles N corresponding to the M independent flow channels RK.

[0131] Furthermore, in the liquid ejector head 1 according to this embodiment, the circulating flow channel J11 is connected to the common flow channel R1 at its end on the Y2 side in the Y-axis direction, the circulating flow channel J12 is connected to the common flow channel R1 at its end on the Y1 side in the Y-axis direction, the circulating flow channel J22 is connected to the common flow channel R2 at its end on the Y1 side in the Y-axis direction, and the circulating flow channel J21 is connected to the common flow channel R2 at its end on the Y2 side in the Y-axis direction.

[0132] Therefore, according to this embodiment, compared with, for example, the circulation channel J11 being connected to the common channel R1 at its central portion in the Y-axis direction, and the circulation channel J12 being connected to the common channel R1 at its central portion in the Y-axis direction, and the circulation channel J22 being connected to the common channel R2 at its central portion in the Y-axis direction, and the circulation channel J21 being connected to the common channel R2 at its central portion in the Y-axis direction, the continuous development of thickening in the common channel R1 and the continuous development of thickening in the common channel R2 can be suppressed.

[0133] Furthermore, in the liquid ejector head 1 according to this embodiment, the pressure P11 applied to the ink in the circulation channel J11 is higher than the pressure P12 applied to the ink in the circulation channel J12, and the pressure P22 applied to the ink in the circulation channel J22 is higher than the pressure P21 applied to the ink in the circulation channel J21.

[0134] Therefore, according to this embodiment, the ink in the common flow channel R1 can be circulated from the circulation flow channel J11 to the circulation flow channel J12, and the ink in the common flow channel R2 can be circulated from the circulation flow channel J22 to the circulation flow channel J21. Therefore, according to this embodiment, compared with a method that does not circulate the ink in the common flow channel R, the continuous development of thickening in the common flow channel R can be suppressed.

[0135] Furthermore, in the liquid ejector head 1 according to this embodiment, the pressure P11 applied to the ink in the circulation channel J11 is higher than the pressure P21 applied to the ink in the circulation channel J21, and the pressure P12 applied to the ink in the circulation channel J12 is higher than the pressure P22 applied to the ink in the circulation channel J22.

[0136] Therefore, according to this embodiment, the pressure applied to the ink in the common channel R1 connecting the circulation channels J11 and J12 becomes higher than the pressure applied to the ink in the common channel R2 connecting the circulation channels J22 and J21. Therefore, according to this embodiment, ink can be circulated from the common channel R1 to the common channel R2 via the independent channel RK, thereby achieving a smooth ink supply to the independent channel RK.

[0137] Furthermore, in the liquid ejector head 1 according to this embodiment, the pressure P21 applied to the ink in the circulation channel J21 is different from the atmospheric pressure PC by a greater degree than the pressure P11 applied to the ink in the circulation channel J11 is different from the atmospheric pressure PC by a greater degree than the pressure P22 applied to the ink in the circulation channel J22 is different from the atmospheric pressure PC by a greater degree than the pressure P12 applied to the ink in the circulation channel J12 is different from the atmospheric pressure PC by a greater degree.

[0138] Therefore, according to this embodiment, the pressure on the ink near the nozzle N in the independent flow channel RK[m], i.e., the nozzle proximity pressure PN[m], can be set to a pressure lower than atmospheric pressure PC. Therefore, according to this embodiment, leakage of ink from the nozzle N can be suppressed.

[0139] Furthermore, in the liquid ejector head 1 according to this embodiment, the pressure P11 applied to the ink in the circulation channel J11 is higher than the atmospheric pressure PC, the pressure P12 applied to the ink in the circulation channel J12 is higher than the atmospheric pressure PC, the pressure P22 applied to the ink in the circulation channel J22 is lower than the atmospheric pressure PC, and the pressure P21 applied to the ink in the circulation channel J21 is lower than the atmospheric pressure PC.

[0140] Therefore, according to this embodiment, the pressure applied to the ink in the common channel R1 connecting the circulation channels J11 and J12 becomes higher than the pressure applied to the ink in the common channel R2 connecting the circulation channels J22 and J21. Therefore, according to this embodiment, ink can be circulated from the common channel R1 to the common channel R2 via the independent channel RK, and a smooth ink supply to the independent channel RK can be achieved.

[0141] Furthermore, in the liquid ejector head 1 according to this embodiment, the sum of the pressure P11 applied to the ink in the circulation channel J11 and the pressure P21 applied to the ink in the circulation channel J21 is approximately the same as the sum of the pressure P12 applied to the ink in the circulation channel J12 and the pressure P22 applied to the ink in the circulation channel J22.

[0142] Therefore, according to this embodiment, compared with the method where the sum of pressure P11 and pressure P21 is different from the sum of pressure P12 and pressure P22, the deviation of the pressure applied to the ink near the M nozzles N corresponding to the M independent flow channels RK can be reduced, thereby reducing the deviation of the ejection characteristics of the ink from the M nozzles N corresponding to the M independent flow channels RK.

[0143] Furthermore, the liquid ejection device 100 according to this embodiment is characterized by comprising: a liquid ejection head 1; and a control device 7, which controls the pressure regulating device 83 and outputs a control signal SI to control the ejection of ink from the liquid ejection head 1. The pressure regulating device 83 regulates the pressure P11 in the circulation channel J11, the pressure P12 in the circulation channel J12, the pressure P22 in the circulation channel J22, and the pressure P21 in the circulation channel J21.

[0144] Therefore, according to this embodiment, it is possible to suppress the continuous thickening development within the common flow channel R1 and the common flow channel R2 while simultaneously achieving the formation of an image of the medium PP by ejecting ink from the liquid ejector head 1.

[0145] B. Variations

[0146] The methods illustrated above can be modified in various ways. Specific modifications are illustrated below. Any two or more methods selected from the following examples can be appropriately combined within the bounds of non-contradiction.

[0147] Variation Example 1

[0148] In the above embodiments, the ink may also be an ink that has properties such as plasticity and thixotropy, which reduce viscosity through shear stress. In this case, a structure for making the shear stress act on the ink may also be provided in the common flow channel R1.

[0149] Figure 8 This is a top view used to illustrate the structure of the liquid ejector head 1B involved in this modified example. Specifically, in Figure 8 The figure shows the flow of ink in the liquid ejector head 1B when viewed from above in the Z1 direction.

[0150] like Figure 8 As shown, the liquid nozzle 1B differs from the liquid nozzle 1 of the embodiment in that it has a common flow channel RB1 instead of a common flow channel R1. Furthermore, in the liquid nozzle 1B of this modified example, in the common flow channel RB1, as indicated by arrow EB1, the ink flows in the Y1 direction; in the common flow channel R2, as indicated by arrow EB2, the ink flows in the Y2 direction; and in the independent flow channel RK[m], as indicated by arrow FB[m], the ink flows in the X2 direction.

[0151] The common flow channel RB1 differs from the common flow channel R1 in that it has a narrow section RB12. Specifically, the common flow channel RB1 has: a connecting section RB11 that communicates with the circulating flow channel J11, a common section RB13 that communicates with M independent flow channels RK[1] to RK[M] and also communicates with the circulating flow channel J12, and a narrow section RB12 disposed between the connecting section RB11 and the common section RB13. The cross-sectional area S12 of the narrow section RB12 is smaller than the cross-sectional area S11 of the connecting section RB11 and smaller than the cross-sectional area S13 of the common section RB13.

[0152] In this modified example, the ink supplied from the circulation channel J11 has pseudoplasticity or thixotropy, thereby reducing viscosity through shear stress.

[0153] In other words, in this modified example, the ink supplied from the circulation channel J11 experiences shear stress as it passes through the narrow section RB12, resulting in a decrease in viscosity. Therefore, in this modified example, the ink supplied from the circulation channel J11 can circulate smoothly in the common channel R1, the independent channel RK[m], and the common channel R2.

[0154] Variation Example 2

[0155] Although the above embodiments and variations 1 illustrate and describe the case where the M independent flow channels RK[1] to RK[M] each have approximately the same shape and approximately the same size, the present invention is not limited to this manner. The M independent flow channels RK[1] to RK[M] may also include one independent flow channel RK and an independent flow channel RK with a different shape than that one independent flow channel RK. Furthermore, the M independent flow channels RK[1] to RK[M] may also include one independent flow channel RK and an independent flow channel RK with a different size than that one independent flow channel RK.

[0156] Figure 9 This is a top view used to illustrate the structure of the liquid ejector head 1C involved in this modified example. Specifically, in Figure 9 The figure shows the flow of ink in the liquid ejector head 1C when viewed from above in the Z1 direction.

[0157] like Figure 9As shown, the liquid nozzle 1C differs from the liquid nozzle 1 of the embodiment in that it has a common flow channel RC1 instead of a common flow channel R1, a common flow channel RC2 instead of a common flow channel R2, and independent flow channels RKC[1] to RKC[M] instead of independent flow channels RK[1] to RK[M]. The common flow channel RC1 differs from the common flow channel R1 of the embodiment in that it connects with the M independent flow channels RKC[1] to RKC[M] instead of the M independent flow channels RK[1] to RK[M]. The common flow channel RC2 differs from the common flow channel R2 of the embodiment in that it connects with the M independent flow channels RKC[1] to RKC[M] instead of the M independent flow channels RK[1] to RK[M]. Furthermore, in the liquid ejector head 1C involved in this modified example, in the common flow channel RC1, as indicated by arrow EC1, the ink flows from the Y2 side toward the Y1 side; in the common flow channel RC2, as indicated by arrow EC2, the ink flows from the Y1 side toward the Y2 side; and in the independent flow channel RKC[m], as indicated by arrow FC[m], the ink flows toward the X2 direction.

[0158] The independent flow channel RKC[m] differs from the independent flow channel RK[m] in the embodiment in that it has a connecting flow channel BKC1[m] instead of a connecting flow channel BK1, and a connecting flow channel BKC2[m] instead of a connecting flow channel BK2.

[0159] Independent flow channels RKC[1] to RKC[M] include independent flow channels RKC[m1] and independent flow channels RKC[m2]. Here, variable m1 is a natural number satisfying 1≤m1<m2, and variable m2 is a natural number satisfying m1<m2≤M. In this modified example, the flow resistance of independent flow channel RKC[m1] is greater than that of independent flow channel RKC[m2]. Specifically, in this modified example, the connecting flow channel BKC1[m1] in independent flow channel RKC[m1] is longer than the connecting flow channel BKC1[m2] in independent flow channel RKC[m2]. Furthermore, in this modified example, the connecting flow channel BKC2[m1] in independent flow channel RKC[m1] is longer than the connecting flow channel BKC2[m2] in independent flow channel RKC[m2]. However, the present invention is not limited to such a manner. For example, it can also be done in the following manner: the cross-sectional area of ​​connecting channel BKC1[m1] is smaller than the cross-sectional area of ​​connecting channel BKC1[m2], and the cross-sectional area of ​​connecting channel BKC2[m1] is smaller than the cross-sectional area of ​​connecting channel BKC2[m2]. Furthermore, in this modified example, independent channel RKC[m1] is an example of a "first independent channel," and independent channel RKC[m2] is an example of a "second independent channel."

[0160] Even in Figure 9 In the example shown, similarly to the embodiment, the pressure on the ink in the connection portion with the independent flow channel RKC[m] in the common flow channel RC1 is referred to as the pressure near the independent flow channel PR1[m], and the pressure on the ink in the connection portion with the independent flow channel RKC[m] in the common flow channel RC2 is referred to as the pressure near the independent flow channel PR2[m].

[0161] exist Figure 9 In the example shown, the difference between the pressure PR1[m1] and the pressure PR2[m1] near the independent flow channel is greater than the difference between the pressure PR1[m2] and the pressure PR2[m2] near the independent flow channel. Therefore, if the flow resistance of the independent flow channel RKC[m1] is approximately the same as that of the independent flow channel RKC[m2], the ink flow rate in the independent flow channel RKC[m1] becomes faster than the ink flow rate in the independent flow channel RKC[m2].

[0162] In contrast, in this modified example, the flow resistance of the independent flow channel RKC[m1] is set to be greater than that of the independent flow channel RKC[m2]. Therefore, according to this modified example, compared with the method of setting the flow resistance of the independent flow channels RKC[m1] and RKC[m2] to be approximately the same, the flow rates of the ink in the independent flow channels RKC[m1] and RKC[m2] can be made closer. Thus, according to this modified example, compared with the method of setting the flow resistance of the independent flow channels RKC[m1] and RKC[m2] to be approximately the same, the deviation in the ink ejection characteristics from the M nozzles N corresponding to the M independent flow channels RKC[1] to RKC[M] can be reduced.

[0163] Figure 10 This is a top view used to illustrate the structure of the liquid ejector head 1D involved in this modified example. Specifically, in Figure 10 The figure shows the flow of ink in the liquid ejector head 1D when viewed from above in the Z1 direction.

[0164] like Figure 10As shown, the liquid nozzle 1D differs from the liquid nozzle 1 of the embodiment in that it has independent flow channels RKD[1] to RKD[M] instead of independent flow channels RK[1] to RK[M]. Furthermore, in the liquid nozzle 1D of this modified example, in the common flow channel R1, as indicated by arrow ED1, the ink flows in the Y1 direction; in the common flow channel R2, as indicated by arrow ED2, the ink flows in the Y2 direction; and in the independent flow channel RKD[m], as indicated by arrow FD[m], the ink flows in the X2 direction.

[0165] The independent flow channel RKD[m] differs from the independent flow channel RK[m] in the embodiment in that it has a pressure chamber CVD1[m] instead of pressure chamber CV1, and a pressure chamber CVD2[m] instead of pressure chamber CV2.

[0166] Independent flow channels RKD[1] to RKD[M] include independent flow channels RKD[m1] and independent flow channels RKD[m2]. In this modified example, the volume of pressure chamber CVD1[m1] in independent flow channel RKD[m1] is larger than the volume of pressure chamber CVD1[m2] in independent flow channel RKD[m2]. Furthermore, in this modified example, the volume of pressure chamber CVD2[m1] in independent flow channel RKD[m1] is larger than the volume of pressure chamber CVD2[m2] in independent flow channel RKD[m2]. However, the present invention is not limited to this manner. For example, it is also possible to adopt the manner in which the volume of independent flow channel RKD[m1] is larger than the volume of independent flow channel RKD[m2]. In addition, in this modified example, independent flow channel RKD[m1] is another example of a "first independent flow channel", and independent flow channel RKD[m2] is another example of a "second independent flow channel".

[0167] Even in Figure 10 In the example shown, similarly to the embodiment, the pressure on the ink in the connection portion with the independent flow channel RKD[m] in the ink applied in the common flow channel R1 is called the pressure near the independent flow channel PR1[m], and the pressure on the ink in the connection portion with the independent flow channel RKD[m] in the ink applied in the common flow channel R2 is called the pressure near the independent flow channel PR2[m].

[0168] exist Figure 10In the example shown, the difference between the pressure PR1[m1] and the pressure PR2[m1] near the independent flow channel is greater than the difference between the pressure PR1[m2] and the pressure PR2[m2] near the independent flow channel. Therefore, assuming that the volume of the independent flow channel RKD[m1] is approximately the same as that of the independent flow channel RKD[m2], the ink flow rate in the independent flow channel RKD[m1] becomes faster than the ink flow rate in the independent flow channel RKD[m2].

[0169] In contrast, in this modified example, the volume of the independent flow channel RKD[m1] is set to be larger than the volume of the independent flow channel RKD[m2]. Therefore, according to this modified example, compared with the method of setting the volumes of the independent flow channels RKD[m1] and RKD[m2] to be approximately the same, the flow rate of ink in the independent flow channel RKD[m1] can be made closer to the flow rate of ink in the independent flow channel RKD[m2]. Thus, according to this modified example, compared with the method of setting the volumes of the independent flow channels RKD[m1] and RKD[m2] to be approximately the same, the deviation in the ejection characteristics of ink from the M nozzles N corresponding to the M independent flow channels RKD[1] to RKD[M] can be reduced.

[0170] Variation Example 3

[0171] Although in the above Figure 9 In the modified example 2 shown, the case where the channel length of the independent channel RKC[m1] is set to be longer than the channel length of the independent channel RKC[m2] is illustrated and explained, but the present invention is not limited to this manner. As described above, when the channel resistance is the same, the ink flow rate in the independent channel RKC[m1] becomes faster than the ink flow rate in the independent channel RKC[m2].

[0172] In contrast, in this modified example, the cross-sectional area when observing the ink flow direction from the independent flow channel RKC[m1] is set to be smaller than the cross-sectional area when observing the ink flow direction from the independent flow channel RKC[m2]. Therefore, since the flow resistance of the independent flow channel RKC[m1] is greater than that of the independent flow channel RKC[m2], the ink flow rate difference can be reduced.

[0173] However, in this case, when the flow resistance of the independent flow channel RKC[m2] becomes too small and piezoelectric elements PZ1 and PZ2 are driven, the pressure released towards the common flow channels RC1 and RC2 instead of the nozzle N increases, which may reduce the ejection characteristics such as the ejection volume. To eliminate this situation, the volume of the pressure chambers CV1 and CV2 of the independent flow channel RKC[m2] can be increased compared to the independent flow channel RKC[m1], the size of the XY plane of the piezoelectric elements PZ1 and PZ2 can be increased, or the driving voltage applied to the piezoelectric elements PZ1 and PZ2 can be increased.

[0174] Variation Example 4

[0175] Although the embodiments and variations 1 to 3 described above illustrate and explain a case where an independent flow channel RK includes two pressure chambers, pressure chamber CV1 and pressure chamber CV2, the present invention is not limited to this configuration. It is also possible for an independent flow channel RK to include only one pressure chamber CV.

[0176] Variation Example 5

[0177] Although the above embodiments and variations 1 to 4 illustrate a serial liquid ejection device 100 in which the housing 921 housing the liquid ejection head 1 reciprocates in the X-axis direction, the present invention is not limited to this manner. The liquid ejection device 100 may also be a row-type liquid ejection device in which multiple nozzles N are distributed across the entire width of the medium PP.

[0178] Variation Example 6

[0179] The liquid ejection apparatus described in the above embodiments and variations 1 to 5 can be used not only in printing equipment but also in various other devices such as fax machines and copiers. Clearly, the application of the liquid ejection apparatus of the present invention is not limited to printing. For example, a liquid ejection apparatus that ejects a solution of color material can be used as a manufacturing apparatus for color filters in liquid crystal display devices. Furthermore, a liquid ejection apparatus that ejects a solution of conductive material can be used as a manufacturing apparatus for wiring and electrodes in wiring boards.

[0180] Symbol Explanation

[0181] 1…Liquid ejector head; 7…Control device; 8…Ink supply device; 83…Pressure regulating device; J11…Circulation channel; J12…Circulation channel; J21…Circulation channel; J22…Circulation channel; R1…Common channel; R2…Common channel; RK…Independent channel; N…Nozzle.

Claims

1. A liquid ejector head, characterized in that, have: Multiple independent flow channels, corresponding to multiple nozzles for ejecting liquid, and configured along a first direction; A first common flow channel, which is connected to one side of the plurality of independent flow channels; The second common flow channel is connected to the other side of the plurality of independent flow channels; A first flow channel, which is connected to the first common flow channel and supplies liquid to the first common flow channel; The second flow channel is connected to the first common flow channel on one side relative to the first flow channel in the first direction, and recovers liquid from the first common flow channel; The third flow channel is connected to the second common flow channel and supplies liquid to the second common flow channel; The fourth flow channel communicates with the second common flow channel on the opposite side from the third flow channel in the first direction, and recovers liquid from the second common flow channel. The first common flow channel has: A connecting section, which is connected to the first flow channel; A common section, which is connected to the plurality of independent flow channels; A narrow portion is disposed between the connecting portion and the common portion, and has a smaller cross-sectional area compared to the connecting portion and the common portion.

2. The liquid ejector head as described in claim 1, characterized in that, The first flow channel communicates with the first common flow channel at its end on the other side of the first direction. The second flow channel communicates with the first common flow channel at one end in the first direction. The third flow channel communicates with the second common flow channel at one end in the first direction. The fourth flow channel is connected to the second common flow channel at its end on the other side of the first direction.

3. The liquid ejector head as described in claim 1, characterized in that, The viscosity of the liquid inside the liquid nozzle is reduced by shear stress.

4. The liquid ejector head as described in claim 1, characterized in that, The pressure applied to the liquid in the first flow channel is higher than the pressure applied to the liquid in the second flow channel. The pressure applied to the liquid in the third flow channel is higher than the pressure applied to the liquid in the fourth flow channel.

5. The liquid ejector head as described in claim 1, characterized in that, The pressure applied to the liquid in the first flow channel is higher than the pressure applied to the liquid in the fourth flow channel. The pressure applied to the liquid in the second flow channel is higher than the pressure applied to the liquid in the third flow channel.

6. The liquid ejector head as described in claim 5, characterized in that, The degree of pressure difference between the liquid applied in the fourth flow channel and atmospheric pressure is greater than the degree of pressure difference between the liquid applied in the first flow channel and atmospheric pressure. The degree of difference between the pressure applied to the liquid in the third flow channel and the atmospheric pressure is greater than the degree of difference between the pressure applied to the liquid in the second flow channel and the atmospheric pressure.

7. The liquid ejector head as described in claim 1, characterized in that, The pressure applied to the liquid within the first flow channel is higher than atmospheric pressure. The pressure applied to the liquid within the second flow channel is higher than atmospheric pressure. The pressure applied to the liquid within the third flow channel is lower than atmospheric pressure. The pressure applied to the liquid in the fourth flow channel is lower than atmospheric pressure.

8. The liquid ejector head as described in claim 1, characterized in that, The sum of the pressure applied to the liquid in the first flow channel and the pressure applied to the liquid in the fourth flow channel is approximately the same as the sum of the pressure applied to the liquid in the second flow channel and the pressure applied to the liquid in the third flow channel.

9. The liquid ejector head as described in claim 5, characterized in that, The plurality of independent flow channels include: First independent flow channel; The second independent flow channel is configured on one side of the first direction, compared to the first independent flow channel. The flow resistance of the first independent flow channel is greater than that of the second independent flow channel.

10. The liquid ejector head as described in claim 5, characterized in that, The plurality of independent flow channels include: First independent flow channel; The second independent flow channel is configured on one side of the first direction, compared to the first independent flow channel. The volume of the first independent flow channel is larger than the volume of the second independent flow channel.

11. A liquid ejection device, characterized in that, have: The liquid ejector head according to any one of claims 1 to 10; A control device controls a pressure regulating device to control the ejection of liquid from the liquid nozzle. The pressure regulating device regulates the pressure in the first flow channel, the second flow channel, the third flow channel, and the fourth flow channel.

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