Liquid discharge head, liquid discharge apparatus, and nozzle substrate

Abstract

A liquid ejecting head, a liquid ejecting apparatus, and a nozzle substrate are provided. The liquid ejecting head includes a first driving element, a first pressure chamber divided in a pressure chamber substrate and applying pressure to a liquid by driving of the first driving element, and a first nozzle formed on a nozzle substrate and communicating with the first pressure chamber to eject the liquid, the nozzle substrate having a first face and a second face closer to the pressure chamber substrate than the first face, the first nozzle including a first upstream nozzle portion including a first supply opening opening on the second face and a first bottom face opposite to the first supply opening, and a first downstream nozzle portion including a first ejection opening opening on the first face and a first connecting portion opening on the first bottom face, a cross-sectional area of the first upstream nozzle portion being larger than a cross-sectional area of the first downstream nozzle portion when viewed in a thickness direction of the nozzle substrate, and a center of gravity of the first connecting portion being located between a center of gravity of the first ejection opening and a center of gravity of the first bottom face.

Description

Technical Field

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

[0002] A liquid ejector head having a nozzle substrate having nozzles for ejecting liquids such as ink has been known for a long time. The liquid ejector head forms an image on a medium by ejecting liquid from the nozzles onto the medium. For example, Patent Document 1 discloses a liquid ejector head having a nozzle having a downstream nozzle portion that opens on the liquid ejection surface of two sides of the nozzle substrate, and an upstream nozzle portion located near the flow channel for liquid flow compared to the downstream nozzle portion.

[0003] When the nozzle is tilted relative to a direction perpendicular to the ejection surface, the direction of liquid ejection shifts from that direction, causing the position where the liquid lands on the medium to deviate from the ideal landing position. If the position where the liquid lands on the medium deviates from the ideal landing position, the quality of the image formed on the medium deteriorates. Therefore, Patent Document 1 discloses a technique that suppresses the tilting of the nozzle relative to a direction perpendicular to the ejection surface by using light passing through an exposure correction component during the manufacturing process to pattern the photosensitive resin material forming the nozzle.

[0004] However, the aforementioned prior art cannot be applied when the nozzle substrate is not formed of a photosensitive resin material. Furthermore, even when the nozzle substrate is formed of a photosensitive resin material, the configuration of the exposure correction component cannot suppress the tilting of the downstream nozzle portion relative to the direction perpendicular to the ejection surface, causing the liquid ejection direction to deviate from the direction perpendicular to the ejection surface, and consequently, the liquid drop position to deviate from the ideal drop position. Therefore, in this invention, a liquid ejection head, a liquid ejection device, and a nozzle substrate are provided that can suppress the liquid drop position deviation caused by nozzle tilting.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-200920 Summary of the Invention

[0006] The liquid ejector head according to a preferred embodiment of the present invention is characterized by comprising: a first driving element; a first pressure chamber divided in a pressure chamber substrate and subjected to pressure on a liquid by the driving element; a first nozzle formed on a nozzle substrate and communicating with the first pressure chamber for ejecting liquid, the nozzle substrate having a first surface and a second surface closer to the pressure chamber substrate than the first surface; the first nozzle comprising: a first upstream nozzle portion including a first supply opening on the second surface and a first bottom surface opposite to the first supply opening; a first downstream nozzle portion including a first ejection opening on the first surface and a first connecting portion opening on the first bottom surface; wherein, when viewed along the thickness direction of the nozzle substrate, the cross-sectional area of ​​the first upstream nozzle portion is larger than the cross-sectional area of ​​the first downstream nozzle portion, and when viewed along the thickness direction, the center of gravity of the first connecting portion is located between the center of gravity of the first ejection opening and the center of gravity of the first bottom surface.

[0007] The liquid ejection device according to a preferred embodiment of the present invention is characterized by having the liquid ejection head described above.

[0008] The nozzle substrate according to a preferred embodiment of the present invention is characterized by having a first nozzle for ejecting liquid, wherein the nozzle substrate has a first surface and a second surface located on the side opposite to the first surface, the first nozzle comprising: a first upstream nozzle portion including a first supply opening on the second surface and a first bottom surface opposite to the first supply opening; and a first downstream nozzle portion including a first ejection opening on the first surface and a first connecting portion opening on the first bottom surface, wherein when viewed along the thickness direction of the nozzle substrate, the cross-sectional area of ​​the first upstream nozzle portion is larger than the cross-sectional area of ​​the first downstream nozzle portion, and when viewed along the thickness direction, the center of gravity of the first connecting portion is located between the center of gravity of the first ejection opening and the center of gravity of the first bottom surface. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating an example of the structure of the liquid ejection device 100.

[0010] Figure 2 An exploded perspective view of the liquid ejector head 10.

[0011] Figure 3 This is a cross-sectional view of the liquid ejector head 10.

[0012] Figure 4 To Figure 3 A magnified image was taken near nozzle N.

[0013] Figure 5 This is a top view of the area near nozzle N.

[0014] Figure 6 This figure illustrates the nozzle substrate 46-A in the first reference example.

[0015] Figure 7 This figure illustrates the nozzle substrate 46-B in the second reference example.

[0016] Figure 8 This diagram illustrates the positional relationship of adjacent nozzles N.

[0017] Figure 9 This is a top view of the area near the nozzle ND in the first variation.

[0018] Figure 10 This is a cross-sectional view of the nozzle NE involved in the second variation. Detailed Implementation

[0019] 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 technically preferred limitations are added as 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 specified in the following description.

[0020] For ease of explanation, the following description will appropriately use intersecting X-axis, Y-axis, and Z-axis. Furthermore, one direction along the X-axis is the X1 direction, and the opposite direction is the X2 direction. Similarly, opposite directions along the Y-axis are the Y1 and Y2 directions. Furthermore, opposite directions along the Z-axis are the Z1 and Z2 directions.

[0021] Here, typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction within the vertical axis. In other words, the Z2 direction is the direction of gravity. However, the Z-axis may not be a vertical axis, but rather inclined relative to the vertical axis. Furthermore, the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, but are not limited to this; for example, they may intersect at an angle between 80 and 100 degrees.

[0022] 1. First Implementation Method

[0023] 1-1. Overview of the liquid ejection device 100

[0024] Figure 1This is a schematic diagram illustrating a structural example of the liquid ejection device 100. The liquid ejection device 100 of this embodiment is an inkjet printing apparatus that ejects ink, as an example of a liquid, in the form of droplets onto a medium PP. The medium PP is typically printing paper, but any printing material such as resin film or fabric can be used as the medium PP.

[0025] like Figure 1 As shown, the liquid ejection device 100 includes a drive signal generation circuit 2, a liquid container 14, a control module 6, a moving mechanism 5, and a liquid ejection module HU having multiple liquid ejection heads 10. In this embodiment, the liquid ejection module HU has four liquid ejection heads 10. Furthermore, the control module 6 is an example of a "control unit".

[0026] Liquid container 14 is a container for storing ink. Specific examples of liquid container 14 include ink cartridges that are detachable from the liquid dispensing device 100, ink pouches formed of flexible films, and ink refill containers. Furthermore, the type of ink stored in liquid container 14 is arbitrary.

[0027] Control module 6 includes, for example, one or more processing circuits such as a CPU or FPGA, and one or more storage circuits such as semiconductor memory. CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field Programmable Gate Array. Various programs and data are stored in the storage circuits. The processing circuits execute the programs and appropriately use the data to achieve various controls.

[0028] The moving mechanism 5 changes the relative position of the medium PP and the liquid ejection module HU. The moving mechanism 5 has a conveying mechanism 8 and a head moving mechanism 7.

[0029] The conveying mechanism 8, based on the control implemented by the control module 6, conveys the medium PP in the Y2 direction. Figure 1 In the example shown, the conveying mechanism 8 includes a conveying roller that is elongated along the X-axis and a motor that rotates the conveying roller. Furthermore, the conveying mechanism 8 is not limited to a structure using a conveying roller; for example, it could be a structure using a roller or a seamless belt to convey the medium PP by using electrostatic attraction to its outer peripheral surface.

[0030] The head movement mechanism 7, based on control implemented by the control module 6, causes the liquid ejection module HU to reciprocate in the X1 and X2 directions. In this embodiment, the X1 and X2 directions are designated as the main scanning directions, and the X2 direction as the secondary scanning direction. Thus, the liquid ejection device 100 in the first embodiment is a serial liquid ejection device that reciprocates along the X-axis. Figure 1 As shown, the head moving mechanism 7 includes a storage housing 71 for housing the liquid ejection module HU, and a seamless strap 72 for fixing the storage housing 71. Alternatively, the liquid container 14 can be stored together with the liquid ejection module HU in the storage housing 71.

[0031] Based on the control implemented by the control module 6, the liquid ejection module HU ejects ink from the liquid container 14 from multiple nozzles N along the Z2 direction to the medium PP.

[0032] The control module 6 controls the ejection action of the liquid nozzle 10. Specifically, the control module 6 generates a printing signal SI for controlling the liquid nozzle 10, a waveform specification signal dCom for controlling the drive signal generation circuit 2, a signal for controlling the conveying mechanism 8, and a signal for controlling the head moving mechanism 7.

[0033] The waveform specification signal dCom refers to a digital signal that defines the waveform of the drive signal Com. Furthermore, the drive signal Com refers to the signal used to specify the waveform of the drive signal Com. Figure 2 The piezoelectric element PZ described below is driven by an analog signal. The drive signal generation circuit 2 includes a DA conversion circuit and generates a drive signal Com with a waveform specified by the waveform specification signal dCom.

[0034] The printing signal SI refers to a digital signal used to specify the type of operation of the piezoelectric element PZ. Specifically, the printing signal SI specifies the type of operation of the piezoelectric element PZ by indicating whether a drive signal Com is supplied to the piezoelectric element PZ. Here, specifying the type of operation of the piezoelectric element PZ includes, for example, specifying whether to drive the piezoelectric element PZ, or, if the piezoelectric element PZ is driven, specifying whether ink is ejected from the piezoelectric element PZ, or, if the piezoelectric element PZ is driven, specifying the amount of ink ejected from the piezoelectric element PZ.

[0035] First, control module 6 stores the printing data Img supplied from a host computer or digital camera via its own storage circuit. Next, based on the printing data Img and other data stored in the storage circuit, control module 6 generates various control signals, including a printing signal SI, a waveform specification signal dCom, a signal for controlling the conveyor mechanism 8, and a signal for controlling the head movement mechanism 7. Then, based on these control signals and the data stored in its own storage circuit, control module 6 controls the conveyor mechanism 8 and the head movement mechanism 7 by changing the relative position of the medium PP with respect to the liquid ejection module HU, and controls the liquid ejection module HU by driving the piezoelectric element PZ. Thus, control module 6 adjusts the presence or absence of ink ejection from the piezoelectric element PZ, the amount of ink ejected, and the ink ejection timing, thereby controlling the execution of the printing process that forms an image corresponding to the printing data Img on the medium PP.

[0036] 1-2. Overview of Liquid Dispenser 10

[0037] The following is based on... Figure 2 as well as Figure 3 At the same time, a summary of the liquid ejector head 10 is given. Figure 2 An exploded perspective view of the liquid ejector head 10. Figure 3 This is a cross-sectional view of the liquid ejector head 10. Figure 3 The attached diagram shows the liquid ejection head 10 being... Figure 2 The section aa shown is cut and its state is observed along the Y2 direction. Section aa is parallel to the XZ plane and passes through the inlet 424 described later.

[0038] like Figure 2 as well as Figure 3 As illustrated, the liquid nozzle 10 includes a generally rectangular connecting plate 32 that is elongated along the Y-axis. On the Z1 direction surface of the connecting plate 32, a pressure chamber substrate 34, a vibrating plate 36, M piezoelectric elements PZ, a frame portion 42, and a sealing body 44 are provided. In other words, the connecting plate 32 is laminated onto the Z2 direction surface of the pressure chamber substrate 34. On the Z2 direction surface of the connecting plate 32, a nozzle substrate 46 and a malleable substrate 48 are provided. The components of the liquid nozzle 10 are generally plate-shaped members that are elongated along the Y-axis, similar to the connecting plate 32, and are bonded together using an adhesive.

[0039] like Figure 2 As illustrated, the nozzle substrate 46 is a plate-shaped component having M nozzles N arranged in a nozzle array Ln parallel to the Y-axis. The M nozzles N are arranged in a direction along the Y-axis. The nozzle substrate 46 is, for example, a silicon substrate. Figure 3 As illustrated, the nozzle substrate 46 has a surface FN1 facing the Z2 direction and a surface FN2 facing the Z1 direction. Surface FN2 is closer to the pressure chamber substrate 34 than surface FN1. Surface FN1 is an example of a "first surface". Surface FN2 is located on the opposite side of surface FN1 and is an example of a "second surface". The thickness direction of the nozzle substrate 46 is along the Z-axis. In this embodiment, the nozzle array Ln is parallel to the Y-axis and is a line segment from the centroid GD2 of the ejection opening D2 of the downstream nozzle portion ND of the nozzle N closest to the Y1 direction (described later) to the centroid GD2 of the ejection opening D2 of the downstream nozzle portion ND of the nozzle N closest to the Y2 direction. In addition, the arrangement of M nozzles N along the nozzle column Ln also includes the concept of at least a portion of the M nozzles N being arranged in a slightly offset direction intersecting with the nozzle column Ln, which refers to the situation where a portion or all of the M nozzles N overlap when viewed along the nozzle column Ln.

[0040] Each nozzle N is a through-hole through which ink passes. M is an integer greater than or equal to 2. However, M can also be 1. Details regarding the shape of the nozzle N are based on... Figure 4 This will be described in the following text.

[0041] The connecting plate 32 is a plate-shaped component with channels for ink flow. For example... Figure 2 as well as Figure 3 As illustrated, an opening 322, a second connecting channel 324, and a first connecting channel 326 are formed on the connecting plate 32. The opening 322 is a through-hole shared by the M nozzles N along the Y-axis when viewed along the Z-axis. Hereinafter, viewing along the Z-axis will sometimes be referred to as "top view." The second connecting channel 324 and the first connecting channel 326 are through-holes formed individually for each nozzle N. Furthermore, as... Figure 3 As illustrated, a common flow channel 328 spanning M second connecting channels 324 is formed on the surface of the connecting plate 32 in the Z2 direction. The common flow channel 328 is a flow channel that connects the opening 322 and the M second connecting channels 324.

[0042] Furthermore, the connecting plate 32 and the pressure chamber substrate 34 are formed by processing a single-crystal silicon substrate using semiconductor manufacturing techniques such as etching. However, the manufacturing method of each element of the liquid ejector head 10 is arbitrary.

[0043] The frame portion 42 is, for example, a structure manufactured by injection molding of resin material, and it is fixed to the surface of the connecting plate 32 in the Z1 direction. Figure 3As illustrated, a receiving portion 422 and an inlet 424 are formed on the frame portion 42. The receiving portion 422 is a recessed portion with a shape corresponding to the opening 322 of the connecting plate 32. The inlet 424 is a through hole communicating with the receiving portion 422. According to... Figure 3 As understood, the space connecting the opening 322 of the connecting plate 32 and the receiving portion 422 of the frame portion 42 functions as a liquid storage chamber RS. Ink supplied from the liquid container 14 and passing through the inlet 424 is stored in the liquid storage chamber RS.

[0044] The malleable substrate 48 has the function of buffering the vibration of ink in the liquid storage chamber RS. The malleable substrate 48 includes, for example, a flexible sheet member capable of elastic deformation. Specifically, the malleable substrate 48 is provided on the surface of the connecting plate 32 in the Z2 direction to seal the opening 322, the common flow channel 328 and the plurality of second connecting channels 324 of the connecting plate 32 and form the bottom surface of the liquid storage chamber RS.

[0045] like Figure 2 as well as Figure 3 As illustrated, the pressure chamber substrate 34 is a plate-shaped component having M pressure chambers CV corresponding to M nozzles N respectively. The M pressure chambers CV are arranged at intervals along the Y-axis. Each pressure chamber CV is an opening extending along the X-axis. When viewed from above, the X1 end of the pressure chamber CV overlaps with a second connecting channel 324, and the X2 end of the pressure chamber CV overlaps with a first connecting channel 326 of the connecting plate 32 when viewed from above.

[0046] A vibrating plate 36 is disposed on a surface of the pressure chamber substrate 34 in the direction opposite to the surface opposite to the connecting plate 32. The vibrating plate 36 is a plate-shaped component capable of elastic deformation. Figure 3 As illustrated, the vibrating plate 36 is constructed by laminating an elastic membrane 361 and an insulating membrane 362. The insulating membrane 362 is positioned in the opposite direction to the pressure chamber substrate 34 when viewed from the elastic membrane 361. The elastic membrane 361 is formed, for example, of silicon oxide. The insulating membrane 362 is formed, for example, of zirconium oxide.

[0047] According to Figure 3As understood, the connecting plate 32 and the vibrating plate 36 are positioned opposite each other at intervals inside each pressure chamber CV. A pressure chamber CV is a space located between the connecting plate 32 and the vibrating plate 36, used to apply pressure to the ink contained within it. The vibrating plate 36 forms part of the wall of the pressure chamber CV. Ink stored in the liquid storage chamber RS ​​is supplied and contained in the M pressure chambers CV in parallel, branching from the common flow channel 328 to each of the second connecting channels 324. That is, the liquid storage chamber RS ​​functions as a common liquid chamber for supplying ink to the multiple pressure chambers CV.

[0048] like Figure 2 as well as Figure 3 As illustrated, on the surface of the vibrating plate 36 in the direction opposite to that of the pressure chamber substrate 34, M piezoelectric elements PZ are provided, each corresponding to one of the M nozzles N. Each piezoelectric element PZ is an actuator that deforms upon the supply of a drive signal Com, and is formed in an elongated shape along the X-axis. The M piezoelectric elements PZ are arranged along the Y-axis in a manner corresponding to the M pressure chambers CV. When the vibrating plate 36 vibrates in conjunction with the deformation of the piezoelectric elements PZ, the pressure within the pressure chambers CV changes. The piezoelectric elements PZ are driving elements that cause the vibrating plate 36 to vibrate.

[0049] In the following text, to distinguish each of the M piezoelectric elements PZ, they will sometimes be referred to sequentially as the 1st, 2nd, ..., Mth. Furthermore, the mth piezoelectric element PZ will sometimes be referred to as piezoelectric element PZ[m]. The variable m is an integer greater than or equal to 1 and less than or equal to M. Additionally, when the structural elements or signals of the liquid ejection device 100 correspond to piezoelectric elements PZ, they may be represented by appending a suffix [m] to the symbol representing that structural element or signal. For example, the mth nozzle N may sometimes be represented as nozzle N[m]. Figure 2 As shown, the nozzle N located in the Y2 direction among the M nozzles N is represented as nozzle N[1], and the nozzle N located in the Y1 direction is represented as nozzle N[M].

[0050] When the vibrating plate 36 vibrates in conjunction with the deformation of the piezoelectric element PZ, the pressure in the pressure chamber CV changes, causing the ink filled in the pressure chamber CV to be ejected through the first connecting channel 326 and the nozzle N.

[0051] Figure 2 as well as Figure 3The sealing body 44 is a structure that protects the M piezoelectric elements PZ from external air and strengthens the mechanical strength of the pressure chamber substrate 34 and the vibrating plate 36. The sealing body 44 is fixed to the surface of the vibrating plate 36, for example, using an adhesive. Multiple piezoelectric elements PZ are housed inside a recess formed on the surface opposite to the vibrating plate 36 within the sealing body 44.

[0052] like Figure 3 As illustrated, a wiring substrate 50 is bonded to the surface of the vibrating plate 36. The wiring substrate 50 is a mounting component with multiple wires forming a plurality of wires for electrical connection between the control module 6 and the liquid nozzle 10. A flexible wiring substrate 50, such as an FPC or FFC, is preferably used. FPC is an abbreviation for Flexible Printed Circuit. FFC is an abbreviation for Flexible Flat Cable. A drive circuit 51 is mounted on the wiring substrate 50. The drive circuit 51 is a circuit that switches the supply of a drive signal Com to the piezoelectric element PZ based on control implemented by the printed signal SI.

[0053] 1-3. Regarding the shape of nozzle N

[0054] Figure 4 To Figure 3 A magnified image was taken near nozzle N. Figure 5 This is a top view of the area near nozzle N. Figure 4 as well as Figure 5 As shown, nozzle N has a downstream nozzle portion ND and an upstream nozzle portion NU located upstream of the downstream nozzle portion ND. The upstream nozzle portion NU includes a supply opening U1 opening on surface FN2 and a bottom surface U2 opposite to the supply opening U1. More specifically, the upstream nozzle portion NU is a generally cylindrical space with the supply opening U1 and the bottom surface U2 as the bottom surface and the wall surface WU as the side surface. The bottom surface U2 is a surface with the Z-axis as its normal vector. In other words, the bottom surface U2 is a surface parallel to the XY plane. However, the bottom surface U2 can also be a surface intersecting the XY plane. In the first embodiment, the shapes of the supply opening U1 and the bottom surface U2 are substantially the same. Therefore, as... Figure 4 as well as Figure 5As shown, when viewed from above, the position of the centroid GU1 of the supply opening U1 is approximately the same as the position of the centroid GU2 of the base U2. The centroid is the point where the sum of the static moments of the cross sections in the shape of an object is zero. For example, in the case of a circular object, the centroid is the center of the circle, while in the case of a parallelogram, the centroid is the intersection of the two diagonals of the parallelogram. "Approximately the same" means, in addition to being completely identical, that it also includes cases where manufacturing errors can be considered identical.

[0055] The downstream nozzle portion ND includes an ejection opening D2 on the surface FN1 and a connecting portion D1 on the bottom surface U2. More specifically, the downstream nozzle portion ND is a generally cylindrical space inclined relative to the Z-axis, with the ejection opening D2 and the connecting portion D1 as the bottom surface and the wall surface WD as the side surface. Figure 5 In this design, the supply opening U1, bottom surface U2, connecting part D1, and ejection opening D2 are circular in shape, but not limited to a circle; they can be any shape, such as an ellipse or a rectangle. The diameter of the connecting part D1 and ejection opening D2 is, for example, between 10 [μm] and 30 [μm]. The diameter of the supply opening U1 and bottom surface U2 is, for example, the smaller of 15 [μm] and an upper limit value corresponding to the resolution of the liquid ejection device 100 and the width of the first connecting channel 326. The upper limit value corresponding to the resolution of the liquid ejection device 100 is, for example, calculated as 25.4 [mm] / 600 when the resolution of the liquid ejection device 100 is 600 dpi, so that the upper limit value is approximately 0.0423 [mm], or in other words, approximately 42.3 [μm]. [μm] refers to micrometers. [mm] refers to millimeters. Dpi is an abbreviation for dots per inch.

[0056] In addition, Figure 4 In this case, the distance G2 from surface FN1 to bottom surface U2 is equal to the distance G1 from bottom surface U2 to surface FN2, but it is not limited to this. For example, the distance G2 can be longer than the distance G1, or the distance G2 can be shorter than the distance G1.

[0057] like Figure 5As shown, in a top-view view, the ejection opening D2 and the connecting portion D1 are located inside the supply opening U1 and the bottom surface U2. Therefore, in a top-view view, the cross-sectional area of ​​the upstream nozzle portion NU is larger than that of the downstream nozzle portion ND. However, it is also possible for part or all of the ejection opening D2 to be located outside the supply opening U1 and the bottom surface U2 in a top-view view. Furthermore, in a top-view view, the areas of the ejection opening D2 and the connecting portion D1 are approximately the same, but their areas can also be different. For example, the downstream nozzle portion ND can also be a conical shape whose cross-sectional area decreases towards the Z2 direction.

[0058] like Figure 4 As shown, the angle θ1 formed by the line segment LD12 connecting the center of gravity GD2 of the ejection opening D2 and the center of gravity GD1 of the connecting part D1 with the Z-axis direction is greater than 0 degrees and less than 90 degrees. For example, the angle θ1 is greater than 0.05 degrees and less than 5 degrees. Figure 4 As shown, the downstream nozzle portion ND is inclined along line segment LD12 relative to surface FN1. In the following description, it may be stated that the inclination of the downstream nozzle portion ND increases depending on the angle θ1, that is, depending on the angle θ1 approaching the direction perpendicular to the Z-axis.

[0059] 1-4. Regarding the ejection direction of nozzle N

[0060] The manufacturing process of the nozzle substrate 46 of the present invention includes: a nozzle forming process in which a downstream nozzle portion ND and an upstream nozzle portion NU are formed on a silicon wafer that constitutes a plurality of nozzle substrates 46; and a process in which the nozzle substrate 46 is cut from the silicon wafer. In the nozzle forming process, dry etching is preferably performed, for example. However, there is a situation where the upstream nozzle portion NU and the downstream nozzle portion ND are tilted relative to the surface FN1 due to deviations in the shape of the mask pattern formed on the silicon wafer during dry etching, or deviations in the density distribution of the plasma used in dry etching, etc. Figure 6 The nozzle substrate 46-A in the first reference example, in which the downstream nozzle portion ND is tilted relative to the vertical direction of the surface FN1, will be described.

[0061] Figure 6 This figure illustrates the nozzle substrate 46-A in the first reference example. Figure 6 The image shows a cross-section of the nozzle NA formed on the nozzle substrate 46-A. The nozzle NA in the first reference example differs from the nozzle N in that it has a downstream nozzle portion ND-A instead of the downstream nozzle portion ND. Figure 6As shown, the difference between downstream nozzle section ND-A and downstream nozzle section ND is that the centroid GD1-A of the connecting portion D1-A of downstream nozzle section ND-A overlaps with the centroid GU2 of the bottom surface U2 of upstream nozzle section NU. Like downstream nozzle section ND, downstream nozzle section ND-A is inclined along line segment LD12 relative to surface FN1. In other words, downstream nozzle section ND-A is inclined in the X2 direction as it tends towards the Z2 direction. However, downstream nozzle section ND-A is not limited to always being inclined in the X2 direction; as long as it is perpendicular to the Z-axis, it has the possibility of being inclined in any direction.

[0062] In the first reference example, because the ink is ejected along the downstream nozzle portion ND-A, the ink ejection direction is deflected from the Z-axis. In the following text, this deflection of the ink ejection direction from the Z-axis will sometimes be described as "flying bend." Figure 6 In the example shown, the droplets DR ejected from nozzle NA are deflected in the X2 direction. When this flight bend occurs, the position where the ink lands on the media PP deviates from the ideal landing position. This deviation from the ideal landing position degrades the quality of the image formed on the media PP.

[0063] To ensure that the ink ejection direction is close to the Z-axis, consideration was given to suppressing the tilt of the downstream nozzle portion ND during the fabrication of the nozzle substrate 46. However, it is difficult to completely suppress deviations in the shape of the mask pattern formed on the silicon wafer during dry etching, as well as deviations in the density distribution of the plasma used in dry etching. Even assuming that these factors can be completely suppressed, there are situations where the fabrication process of the nozzle substrate 46 becomes complex or requires costly manufacturing equipment.

[0064] As described above, the ink ejection direction is affected by the tilt of the downstream nozzle portion ND-A. On the other hand, through the inventors' experiments, it was learned that the ink ejection direction is also affected by the separation of the center of gravity GU2 of the bottom surface U2 and the center of gravity GD1 of the connecting portion D1 when viewed from above. In the following description, the degree of offset of the position of the center of gravity GU2 relative to the position of the center of gravity GD1 will sometimes be described as "coaxiality". Sometimes, the close proximity of the centers of gravity GD1 and GU2 will be described as a higher degree of coaxiality. Furthermore, the direction from the center of gravity GU2 towards the center of gravity GD1 will sometimes be described as the direction of the coaxiality offset. Hereinafter, using... Figure 7 The nozzle substrate 46-B in the second reference example, where the center of gravity GD1 is separated from the center of gravity GU2 and the coaxiality is relatively low, will be explained.

[0065] Figure 7This figure illustrates the nozzle substrate 46-B in the second reference example. Figure 7 The image shows a cross-section of the nozzle NB formed on the nozzle substrate 46-B. The nozzle NB in ​​the second reference example differs from the nozzle N in that it has a downstream nozzle portion ND-B instead of the downstream nozzle portion ND. According to... Figure 7 As understood, the downstream nozzle portion ND-B differs from the downstream nozzle portion ND in that, when viewed from above, the centroids GD1-B of the connecting portion D1-B and the centroid GD2-B of the ejection opening D2-B overlap; in other words, the downstream nozzle portion ND-B is orthogonal to the surface FN1. That is, in the second reference example, the downstream nozzle portion ND-B is not tilted.

[0066] like Figure 7 As shown, in the second reference example, the ink is ejected in a direction that is tilted from the center of gravity GD1-B towards the center of gravity GU2. In other words, the ink is ejected in a direction that is deflected in the opposite direction to the direction of coaxiality offset. Figure 7 In the example shown, the droplet DR ejected from nozzle NB is ejected in a manner that deviates in the X1 direction. As a reason for the tilting of the ink ejection direction due to the coaxiality shift, the following cases are considered: since the center of gravity GD1-B of the connection part D1-B of the downstream nozzle part ND-B is shifted from the center of gravity GU2 of the bottom surface U2, there are cases where the oscillation of the ink meniscus formed in nozzle N is shifted from the center of gravity GU2 at the ejection timing; the meniscus is pulled into the Z1 direction and reaches the upstream nozzle part NU, causing the meniscus to lean to one side; and a pressure gradient is generated in the downstream nozzle part ND-B in a direction orthogonal to the Z-axis.

[0067] Therefore, the inventors discovered that even if the downstream nozzle portion ND is formed at an angle, the upstream nozzle portion NU can be set in a way that counteracts the offset of the ink ejection direction caused by the angle of the downstream nozzle portion ND, thereby suppressing the offset of the ink ejection direction. In other words, in the manufacturing process of the nozzle substrate 46, after the downstream nozzle portion ND is formed on the silicon wafer, the position of the upstream nozzle portion NU formed on the silicon wafer can be adjusted according to the angle of the downstream nozzle portion ND. For example, when viewed from above, the distance between the center of gravity GD1 and the center of gravity GU2 is formed to be 3 [μm] or more and 15 [μm] or less, preferably 4 [μm] or more and 11 [μm] or less.

[0068] Return to Figure 4 as well as Figure 5 This will be explained. In this embodiment, as... Figure 5As shown, when viewed from above, the center of gravity GD1 of the connecting part D1 is located between the center of gravity GD2 of the ejection opening D2 and the center of gravity GU2 of the bottom surface U2. In the first embodiment, when viewed from above, since the bottom surface U2 and the supply opening U1 have the same shape, it can also be said that the center of gravity GD1 is located between the center of gravity GD2 and the center of gravity GU1 of the supply opening U1. When viewed from above, since the center of gravity GD1 is located between the center of gravity GD2 and the center of gravity GU1, the positions of the center of gravity GD1 and the center of gravity GD2 are necessarily different, the positions of the center of gravity GD1 and the center of gravity GU1 are different, and the positions of the center of gravity GD2 and the center of gravity GU1 are different.

[0069] When viewed from above, it is located between the centers of gravity GD2 and GU2, and is not necessarily limited to being situated at the position overlapping with the line segment LDU connecting the centers of gravity GD2 and GU2. For example... Figure 5 As shown, "located between the centroids GD2 and GU2" means located between the lines LD2 and LU2. Here, line LD2 is a line orthogonal to line segment LDU and passing through the centroid GD2, and line LU2 is a line orthogonal to line segment LDU and passing through the centroid GU2. In other words, when viewed from above, relative to line LD1, which is orthogonal to line segment LDU and passes through the centroid GD1, the centroid GD2 is located in the X2 direction, and the centroid GU2 is located in the X1 direction. In the first embodiment, the case where line segment LDU is along the X-axis will be described.

[0070] When viewed from above, since the center of gravity GD2 is located in the X2 direction relative to the center of gravity GD1, a force in the X2 direction is applied to the ink ejected from nozzle N. Additionally, since the center of gravity GU2 is located in the X1 direction relative to the center of gravity GD1, a force in the X1 direction is applied to the ink ejected from nozzle N. Therefore, the forces in the X1 and X2 directions acting on the ink ejected from nozzle N cancel each other out. As described above, in the liquid ejection head 10 according to the first embodiment, even if the downstream nozzle portion ND is formed at an angle, the offset in the ejection direction can be offset by the offset in coaxiality, thus suppressing flight bending.

[0071] In addition, such as Figure 5 As shown, when viewed from above, the center of gravity GD2 of the ejection opening D2, the center of gravity GD1 of the connecting part D1, and the center of gravity GU2 of the bottom surface U2 are located on the same straight line. In this embodiment, when viewed from above, if the distance between the line segment connecting the centers of gravity GD2 and GU2 and the straight line connecting the center of gravity GD1 is 1 [μm] or less, it can be considered as a manufacturing error that the centers of gravity GD2, GD1, and GU2 are located on the same straight line.

[0072] Figure 8For the diagram used to illustrate the positional relationship of adjacent nozzles N, m1 is set to an integer greater than 2 and less than M-1, and nozzle N[m1-1], nozzle N[m1], and nozzle N[m1+1] are shown. Additionally, in Figure 8 In order to avoid making the accompanying drawings complicated, the symbols for the supply opening U1, bottom surface U2, connecting part D1, and ejection opening D2 have been omitted.

[0073] Additionally, nozzle N[m1] is an example of a "first nozzle". The pressure chamber CV[m1] communicating with nozzle N[m1] corresponds to a "first pressure chamber". The piezoelectric element PZ[m1] applying pressure to the ink within the pressure chamber CV[m1] corresponds to a "first driving element". The upstream nozzle portion NU[m1] of nozzle N[m1] corresponds to a "first upstream nozzle portion", and the downstream nozzle portion ND[m1] corresponds to a "first downstream nozzle portion". The supply opening U1[m1] of the downstream nozzle portion ND[m1] corresponds to a "first supply opening", and the bottom surface U2[m1] corresponds to a "first bottom surface". The ejection opening D2[m1] of the downstream nozzle portion ND[m1] corresponds to a "first ejection opening", and the connecting portion D1[m1] corresponds to a "first connecting portion". Although in Figure 8 It is not illustrated in the text, but... Figure 4 When the nozzle N shown is equivalent to the "first nozzle", Figure 4 The line segment LD12 connecting the centroids GD2 and GD1 is equivalent to the "first line segment", and the angle θ1 between line segment LD12 and the Z-axis is equivalent to the "first angle".

[0074] Additionally, for any integer m2 from 1 to M that is different from m1, nozzle N[m2] is an example of a "second nozzle". Figure 8In the example, if m2 is considered as m1-1, then nozzle N[m1-1] can also be considered as an example of a "second nozzle". When nozzle N[m1-1] is a "second nozzle", the pressure chamber CV[m1-1] connected to nozzle N[m1-1] is equivalent to a "second pressure chamber". The piezoelectric element PZ[m1-1] that applies pressure to the ink within the pressure chamber CV[m1-1] is equivalent to a "second driving element". The upstream nozzle portion NU[m1-1] of nozzle N[m1-1] is equivalent to a "second upstream nozzle portion", and the downstream nozzle portion ND[m1-1] is equivalent to a "second downstream nozzle portion". The supply opening U1[m1-1] of the upstream nozzle portion NU[m1-1] is an example of a "second supply opening", and the bottom surface U2[m1-1] is an example of a "second bottom surface". The downstream nozzle portion ND[m1-1] has an ejection opening D2[m1-1] as an example of a "second ejection opening", and a connecting portion D1[m1-1] as an example of a "second connecting portion". Although in Figure 8 Not shown in the text, but in Figure 4 When the nozzle N shown is equivalent to the "second nozzle", the line segment LD12 connecting the center of gravity GD2 and the center of gravity GD1 is equivalent to the "second line segment", and the angle θ1 formed by the line segment LD12 and the Z-axis is equivalent to the "second angle".

[0075] Furthermore, nozzle N[m1-1] is located next to nozzle N[m1]. Therefore, nozzle N[m1-1] can also be considered as an example of a "third nozzle". In the case that nozzle N[m1-1] is a "third nozzle", the pressure chamber CV[m1-1] connected to nozzle N[m1-1] is equivalent to a "third pressure chamber". The piezoelectric element PZ[m1-1] that applies pressure to the ink in the pressure chamber CV[m1-1] is equivalent to a "third driving element". The upstream nozzle portion NU[m1-1] of nozzle N[m1-1] is equivalent to a "third upstream nozzle portion", and the downstream nozzle portion ND[m1-1] is equivalent to a "third downstream nozzle portion". The supply opening U1[m1-1] of the upstream nozzle portion NU[m1-1] is an example of a "third supply opening", and the bottom surface U2[m1-1] is an example of a "third bottom surface". The downstream nozzle portion ND[m1-1] has an ejection opening D2[m1-1] as an example of a "third ejection opening", and the connecting portion D1[m1-1] is an example of a "third connecting portion".

[0076] Nozzle N[m1+1] is located next to nozzle N[m1], and in the opposite direction to the direction from nozzle N[m1] toward nozzle N[m1-1], i.e., the Y1 direction. Therefore, nozzle N[m1+1] can be considered as an example of a "fourth nozzle". In the case that nozzle N[m1+1] is a "fourth nozzle", the pressure chamber CV[m1+1] connected to nozzle N[m1+1] is equivalent to a "fourth pressure chamber". The piezoelectric element PZ[m1+1] that applies pressure to the ink in the pressure chamber CV[m1+1] is equivalent to a "fourth driving element". The upstream nozzle portion NU[m1+1] of nozzle N[m1+1] is equivalent to a "fourth upstream nozzle portion", and the downstream nozzle portion ND[m1+1] is equivalent to a "fourth downstream nozzle portion". The supply opening U1[m1+1] of the upstream nozzle portion NU[m1+1] is an example of a "fourth supply opening", and the bottom surface U2[m1+1] is an example of a "fourth bottom surface". The downstream nozzle portion ND[m1+1] has an ejection opening D2[m1+1] as an example of a "fourth ejection opening", and the connecting portion D1[m1+1] is an example of a "fourth connecting portion".

[0077] exist Figure 8 In the example, the downstream nozzle portion ND[m1-1] of nozzle N[m1-1] is tilted in the X2 direction. The downstream nozzle portion ND[m] of nozzle N[m] is tilted in the W1 direction. The W1 direction is the direction obtained by rotating the Y1 direction clockwise by 45 degrees when viewed along the Z2 direction. The downstream nozzle portion ND[m1+1] of nozzle N[m1+1] is tilted in the Y1 direction. For simplicity, the explanation is based on the premise that the positions of the bottom surface U2[m1-1], the bottom surface U2[m1], and the bottom surface U2[m1+1] on the Z-axis are approximately the same.

[0078] The nozzle substrate 46 according to this embodiment has the characteristic that, as the tilt of the downstream nozzle portion ND increases, the coaxiality offset increases. Specifically, in Figure 8In the example, when viewed from above, the distance L1[m1] between the center of gravity GD1[m1] of the connecting part D1[m1] and the center of gravity GD2 of the ejection opening D2[m1] is longer than the distance L1[m1-1] between the center of gravity GD1[m1-1] of the connecting part D1[m1-1] and the center of gravity GD2 of the ejection opening D2[m1-1]. Given that the positions of the bottom surface U2[m1-1] and the bottom surface U2[m1] on their respective Z-axis are approximately the same, when distance L1[m1] is longer than distance L1[m1-1], it is inevitable that the angle between the line segment connecting the centers of gravity GD2[m1] and GD1[m1] and the Z-axis is greater than the angle between the line segment connecting the centers of gravity GD2[m1-1] and GD1[m1-1] and the Z-axis. In other words, the downstream nozzle section ND[m1] is more inclined compared to the downstream nozzle section ND[m1-1]. As the inclination of the downstream nozzle section ND increases, the degree of ink ejection direction shift also increases. Therefore, in Figure 8 In the example, the distance L2[m1] between the centroid GU2[m1] of the bottom surface U2[m1] and the centroid GD1 of the connecting part D1[m1] is longer than the distance L2[m1-1] between the centroid GU2[m1-1] of the bottom surface U2[m1-1] and the centroid GD1[m1-1] of the connecting part D1[m1-1].

[0079] The nozzle substrate 46 according to this embodiment has the following feature: the spacing between adjacent ejection openings D2 is closer to being fixed than the spacing between adjacent bottom surfaces U2. In other words, the deviation in the spacing between adjacent ejection openings D2 is smaller than the deviation in the spacing between adjacent bottom surfaces U2. Specifically, as according to Figure 8 As understood, the absolute value of the difference between distances LG1 and LG2 is less than the absolute value of the difference between distances LG3 and LG4. Distance LG1 is the distance, viewed from above, from the center of gravity GD2[m1] of the ejection opening D2[m1] to the center of gravity GD2[m1-1] of the ejection opening D2[m1-1]. Distance LG2 is the distance, viewed from above, from the center of gravity GD2[m1] of the ejection opening D2[m1] to the center of gravity GD2[m1+1] of the ejection opening D2[m1+1]. Distance LG3 is the distance, from the center of gravity GU2[m1] of the bottom surface U2[m1] to the center of gravity GU2[m1-1] of the bottom surface U2[m1-1]. The distance LG4 is the distance from the centroid GU2[m1] of the bottom surface U2[m1] to the centroid GU2[m1+1] of the bottom surface U2[m1+1]. Figure 8 In the example, the absolute value of the difference between distance LG1 and distance LG2 is approximately zero.

[0080] Additionally, here's an example of distance LG1 as the "first distance". Here's an example of distance LG2 as the "second distance". Here's an example of distance LG3 as the "third distance". Here's an example of distance LG4 as the "fourth distance".

[0081] In addition, as according to Figure 8 As understood, the centroid GD2 of each of the M ejector openings D2 is located on the nozzle array Ln, which is parallel to the Y-axis. In other words, the centroid GD2 of each of the M ejector openings D2 is roughly at the same position on the X-axis. On the other hand, the upstream nozzle section NU is set according to the tilt direction and degree of tilt of the downstream nozzle section ND. Therefore, there is a possibility that the centroid GU2 of each of the M bottom surfaces U2 is at different positions on the X-axis.

[0082] 1-5. Summary of the First Implementation Method

[0083] Hereinafter, the first embodiment will be summarized using the m1-th piezoelectric element PZ[m1] out of the M piezoelectric elements PZ. m1 is an integer greater than or equal to 1 and less than or equal to M.

[0084] 0068 and above, the liquid ejector head 10 according to the first embodiment includes: a piezoelectric element PZ[m1]; a pressure chamber CV[m1], which is divided in a pressure chamber substrate 34 and applies pressure to ink by being driven by the piezoelectric element PZ[m1]; and a nozzle N[m1], which is formed on a nozzle substrate 46 and communicates with the pressure chamber CV[m1] to eject ink. The nozzle substrate 46 has a surface FN1 and a surface FN2 that is closer to the pressure chamber substrate 34 than the surface FN1. The nozzle N[m1] includes: an upstream nozzle portion NU[m1], which includes a supply opening U1[m1] that opens on the surface FN2 and a supply opening U1[m1] that opens on the surface FN2. The bottom surface U2[m1] opposite U1[m1]; the downstream nozzle portion ND[m1], which includes an ejection opening D2[m1] opening on the surface FN1 and a connecting portion D1[m1] opening on the bottom surface U2[m1]. When viewed along the thickness direction of the nozzle substrate 46, in other words, along the Z-axis, the cross-sectional area of ​​the upstream nozzle portion NU[m1] is larger than that of the downstream nozzle portion ND[m1]. When viewed along the Z-axis, the centroid GD1[m1] of the connecting portion D1[m1] is located between the centroid GD2[m1] of the ejection opening D2[m1] and the centroid GU2[m1] of the bottom surface U2[m1].

[0085] The fact that the center of gravity GD1[m1] is located between the centers of gravity GD2[m1] and GU2[m1] means that the offset in the ejection direction from the center of gravity GD1[m1] towards the center of gravity GD2[m1] due to the tilt of the downstream nozzle section ND[m1], and the offset in the ejection direction from the center of gravity GD1[m1] towards the center of gravity GU2[m1] due to the offset in coaxiality, will cancel each other out. Figure 5 In the example, the offset in the ejection direction in the X2 direction caused by the tilt of the downstream nozzle portion ND and the offset in the ejection direction in the X1 direction caused by the offset in coaxiality cancel each other out. Therefore, in the liquid ejection head 10 according to the first embodiment, even if the downstream nozzle portion ND[m1] is formed at an angle, the offset in the ejection direction can be canceled out by the offset in coaxiality, thus suppressing flight bending.

[0086] Furthermore, the angle θ1[m1] between the line segment LD12[m1] connecting the centroid GD2[m1] of the ejection opening D2[m1] and the centroid GD1[m1] of the connecting part D1[m1] and the direction along the Z-axis is greater than 0 degrees and less than 90 degrees, and the downstream nozzle part ND[m1] is inclined along the line segment LD12[m1] relative to the surface FN1.

[0087] Furthermore, when viewed along the Z-axis, the center of gravity GD2[m1] of the ejection opening D2[m1], the center of gravity GD1[m1] of the connecting part D1[m1], and the center of gravity GU2[m1] of the bottom surface U2[m1] are located on the same straight line.

[0088] In the following text, the m2th piezoelectric element PZ[m2] will be used to summarize the first embodiment. m2 is an integer from 1 to M and is different from m1. The liquid ejector head 10 according to the first embodiment further includes: a piezoelectric element PZ[m2]; a pressure chamber CV[m2], which is divided in the pressure chamber substrate 34 and applies pressure to the ink by being driven by the piezoelectric element PZ[m2]; a nozzle N[m2], which is formed on the nozzle substrate 46 and communicates with the pressure chamber CV[m2] to eject the ink. The nozzle N[m2] includes: an upstream nozzle portion NU[m2], which includes a supply opening U1[m2] opening on the surface FN2 and a bottom surface U2[m2] opposite to the supply opening U1[m2]; and a downstream nozzle portion ND[m2], which includes an ejection opening D2 opening on the surface FN1 and a connecting portion D1[m2] opening on the bottom surface U2[m2]. When viewed along the Z-axis, the cross-sectional area of ​​the upstream nozzle portion NU[m2] is larger than that of the downstream nozzle portion ND[m2]. When observed along the Z-axis, the centroid GD1[m2] of the connecting part D1[m2] is located between the centroid GD2[m2] of the ejection opening D2[m2] and the centroid GU2[m2] of the bottom surface U2[m2]. The angle θ1[m2] between the line segment LD12[m2] connecting the centroid GD2[m2] of the ejection opening D2 and the centroid GD1[m2] of the connecting part D1[m2] and the Z-axis is greater than 0 degrees and less than 90 degrees. (Downstream nozzle section) ND[m2] is inclined along line segment LD12[m2] relative to surface FN1. When the angle θ1[m1] is greater than the angle θ1[m2], when viewed along the Z-axis, the distance between the centroid GU2[m1] of the bottom surface U2[m1] and the centroid GD1[m1] of the connecting part D1[m1] is longer than the distance between the centroid GU2[m2] of the bottom surface U2[m2] and the centroid GD1[m2] of the connecting part D1[m2].

[0089] As the tilt of the downstream nozzle section ND increases, the force causing the shift from the center of gravity GD1 to the center of gravity GD2 due to the tilt of the downstream nozzle section ND increases. Therefore, as the tilt of the downstream nozzle section ND increases, the coaxiality shift increases, thereby enabling appropriate suppression of flight curvature based on the tilt of the downstream nozzle section ND.

[0090] In the following text, m1 will be set as an integer from 2 to M-1, and the m1-1th piezoelectric element PZ[m1-1] and the m1+1th piezoelectric element PZ[m1+1] will be used to summarize the first embodiment. The liquid ejector head 10 according to the first embodiment further includes: a piezoelectric element PZ[m1-1] and a piezoelectric element PZ[m1+1], which are different from the piezoelectric element PZ[m1]; a pressure chamber CV[m1-1], which is divided in the pressure chamber substrate 34 and applies pressure to the ink by driving the piezoelectric element PZ[m1-1]; a nozzle N[m1-1], which is formed on the nozzle substrate 46 and communicates with the pressure chamber CV[m1-1] to eject ink; a pressure chamber CV[m1+1], which is divided in the pressure chamber substrate 34 and applies pressure to the ink by driving the piezoelectric element PZ[m1+1]; and a nozzle N[m1+1], which is formed on the nozzle substrate 46 and communicates with the pressure chamber CV[m1+1] to eject ink. Nozzle N[m1-1] is located next to nozzle N[m1], and nozzle N[m1+1] is located next to nozzle N[m1], and in a direction opposite to that from nozzle N[m1] toward nozzle N[m1-1]. Nozzle N[m1-1] includes: an upstream nozzle portion NU[m1-1], which includes a supply opening U1[m1-1] opening on surface FN2, and a bottom surface U2[m1-1] opposite to the supply opening U1[m1-1]; and a downstream nozzle portion ND[m1-1], which includes an ejection opening D2[m1-1] opening on surface FN1, and a connecting portion D1[m1-1] opening on the bottom surface U2[m1-1]. When viewed along the Z-axis, the cross-sectional area of ​​the upstream nozzle portion NU[m1-1] is larger than that of the downstream nozzle portion ND[m1-1]. When viewed along the Z-axis, the centroid GD1[m1-1] of the connecting portion D1[m1-1] is located between the centroid GD2[m1-1] of the ejection opening D2[m1-1] and the centroid GU2[m1-1] of the bottom surface U2[m1-1]. The nozzle N[m1+1] includes: an upstream nozzle portion NU[m1+1], which includes a supply opening U1[m1+1] opening on the surface FN2 and a bottom surface U2[m1+1] opposite to the supply opening U1[m1+1]; and a downstream nozzle portion ND[m1+1], which includes an ejection opening D2[m1+1] opening on the surface FN1 and a connecting portion D1[m1+1] opening on the bottom surface U2[m1+1]. When observed along the Z-axis, the cross-sectional area of ​​the upstream nozzle portion NU[m1+1] is larger than that of the downstream nozzle portion ND[m1+1]. When observed along the Z-axis, the centroid GD1[m1+1] of the connecting portion D1[m1+1] is located between the centroid GD2[m1+1] of the ejection opening D2[m1+1] and the centroid GU2[m1+1] of the bottom surface U2[m1+1].When observing along the Z-axis, the absolute value of the difference between distances LG1 and LG2 is less than the absolute value of the difference between distances LG3 and LG4 when using the distances LG1 from the center of gravity GD2[m1] of the ejection opening D2[m1] to the center of gravity GD2[m1-1] of the ejection opening D2[m1], LG2 from the center of gravity GD2[m1] of the ejection opening D2[m1] to the center of gravity GD2[m1+1] of the ejection opening D2[m1+1], LG3 from the center of gravity GU2[m1] of the bottom surface U2[m1] to the center of gravity GU2[m1+1] of the bottom surface U2[m1], and LG4 from the center of gravity GU2[m1] of the bottom surface U2[m1] to the center of gravity GU2[m1+1] of the bottom surface U2[m+1].

[0091] Since ink is ejected from the ejection openings D2, if the interval between adjacent ejection openings D2 is not fixed, the interval between the dots formed on the medium PP will also be inconsistent, resulting in a decrease in image quality. Therefore, it is preferable that the interval between adjacent ejection openings D2 is fixed. As described above, in the liquid ejection head 10 according to the first embodiment, compared to a method where the interval between adjacent bottom surfaces U2 is more fixed than the interval between adjacent ejection openings D2, the quality of the image formed on the medium PP can be improved.

[0092] In addition, such as Figure 8 As shown, when viewed from above, the positions of the M ejection openings D2 on the X-axis are approximately the same. When the position of the ejection openings D2 on the X-axis shifts, the starting position for ejection will differ for each nozzle N. If the starting position for ejection differs for each nozzle N, it becomes more difficult to adjust the ejection position. Therefore, in the liquid ejection head 10 according to the first embodiment, it is easier to adjust the ejection position compared to arranging the M bottom surfaces U2 along the Y-axis.

[0093] Furthermore, the liquid ejection device 100 according to the first embodiment includes a liquid ejection head 10. In the liquid ejection device 100 according to the first embodiment, since even if the downstream nozzle portion ND is formed at an angle, the offset of the ejection direction can be offset by the offset of the coaxiality, thus suppressing flight bending.

[0094] Furthermore, the liquid ejector head 10 according to the first embodiment has the nozzle substrate 46 according to the first embodiment. In the nozzle substrate 46 according to the first embodiment, since even if the downstream nozzle portion ND is formed at an angle, the offset of the ejection direction can be offset by the offset of the coaxiality, thus suppressing the flight bend.

[0095] 2. Variations

[0096] The methods illustrated above can be modified in a variety of ways. Specific modifications are illustrated below. Two or more methods selected from the following examples can be appropriately combined within the bounds of non-contradiction.

[0097] 2-1. First variation example

[0098] In the liquid ejector head 10 according to the first embodiment, when viewed from above, the centers of gravity GD2[m1], GD1[m1] and GU2[m1] are located on the same straight line, but the centers of gravity GD2[m1], GD1[m1] and GU2[m1] may also be located at the vertices of a triangle.

[0099] Figure 9 This is a top view near the nozzle ND according to the first modified example. The liquid ejector head 10-D according to the first modified example differs from the liquid ejector head 10 in that it has a nozzle substrate 46-D instead of the nozzle substrate 46. The nozzle substrate 46-D differs from the nozzle substrate 46 in that it has a downstream nozzle portion ND-D instead of the downstream nozzle portion ND. Figure 9 As shown, when viewed from above, the center of gravity GD1-D of the connecting portion D1-D of the downstream nozzle portion ND-D is not located on the line segment LDU-D that connects the center of gravity GD2-D of the ejection opening D2-D and the center of gravity GU2 of the bottom surface U2. In the first modified example, the case where the line segment LDU-D is along the X-axis will be explained.

[0100] When viewed from above, the center of gravity GD1-D lies between the centers of gravity GD2-D and GU2. Specifically, when viewed from above, the center of gravity GD1-D lies between the straight line LD2-D, which passes through the center of gravity GD2-D and is orthogonal to line segment LDU-D, and the straight line LU2, which passes through the center of gravity GU2 and is orthogonal to line segment LDU-D. The downstream nozzle portion ND-D is tilted in the W1 direction from the center of gravity GD1-D toward the center of gravity GD2-D. Therefore, due to the tilt of the downstream nozzle portion ND-D, the ejection direction is shifted in the W1 direction. On the other hand, the direction of the coaxiality shift is in the V1 direction from the center of gravity GU2 toward the center of gravity GD1-D. The V1 direction is the direction obtained by rotating the X2 direction counterclockwise by 45 degrees when viewed along the Z2 direction.

[0101] In the first modification, a force is generated that causes the ink to be ejected in the W1 direction due to the tilt of the downstream nozzle portion ND-D, and a force is generated that causes the ink to be ejected in the opposite direction to the V1 direction, namely the V2 direction, due to the offset of coaxiality. The W1 direction can be decomposed into a component in the X2 direction and a component in the Y1 direction. Furthermore, the V2 direction can be decomposed into a component in the X1 direction and a component in the Y1 direction. Therefore, in the liquid ejector head 10-D according to the first modification, the X2 component of the force that causes the ink to be ejected in the W1 direction and the X1 component of the force that causes the ink to be ejected in the V2 direction cancel each other out. Therefore, in the liquid ejector head 10-D according to the first modification, even if the downstream nozzle portion ND-D is formed at an angle, the offset of the ejection direction can be offset by the offset of coaxiality, thereby suppressing flight bending.

[0102] Comparing the first modified example and the first embodiment, in the first modified example, the Y1 component of the force that ejects ink in the W1 direction is not canceled out by the Y1 component of the force that ejects ink in the V2 direction. On the other hand, in the first embodiment, since the centers of gravity GD2[m1], GD1[m1], and GU2[m1] are located on the same straight line, the direction of ink ejection due to the tilt of the downstream nozzle portion ND and the direction of ink ejection due to the offset of coaxiality are in opposite directions. As described above, the liquid ejection head 10 according to the first embodiment can further suppress flight bending compared to the liquid ejection head 10-D according to the first modified example.

[0103] 2-2. Second variation

[0104] In all the above methods, when viewed from above, the position of the center of gravity GU1 of the supply opening U1 is approximately the same as the position of the center of gravity GU2 of the bottom surface U2, but they can also be different.

[0105] Figure 10 This is a cross-sectional view of the nozzle NE involved in the second modification. The liquid ejector head 10-E involved in the second modification differs from the liquid ejector head 10 in that it has a nozzle substrate 46-E instead of a nozzle substrate 46. The nozzle substrate 46-E differs from the nozzle substrate 46 in that it has an upstream nozzle portion NU-E instead of an upstream nozzle portion NU. The upstream nozzle portion NU-E differs from the upstream nozzle portion NU in that it is tilted at an angle θ2 relative to the Z-axis. Angle θ2 is greater than 0 degrees and less than 90 degrees. Angle θ2 can be the same as or different from angle θ1. Although in Figure 10 In the example, the upstream nozzle section NU-E is tilted in the X1 direction, but the tilting direction is not limited to the X1 direction. It can be any direction as long as it is orthogonal to the Z-axis.

[0106] According to Figure 10 As understood, when viewed from above, the center of gravity GU1-E of the supply opening U1-E of the upstream nozzle portion NU-E and the center of gravity GU2-E of the bottom surface U2-E are located at different positions. In the liquid ejector head 10-E of the second modification, since even if the downstream nozzle portion ND is formed at an angle, the offset of the ejection direction can be offset by the offset of the coaxiality, thus suppressing flight curvature.

[0107] 2-3. Third variation example

[0108] In the above methods, the supply opening U1 and the bottom surface U2 have approximately the same area, but they can also have different areas. For example, the upstream nozzle portion NU can also be a conical shape whose cross-sectional area decreases as it moves toward the Z2 direction.

[0109] 2-4. Fourth variation example

[0110] The liquid ejector heads 10, 10-D, and 10-E in the above-described embodiments can also replace the piezoelectric element PZ and have a heating element that heats the ink in the pressure chamber CV. In the fourth variation, the heating element is an example of a "driving element".

[0111] 2-5. Fifth variation

[0112] Although the liquid ejection device 100 described above is an example of a serial liquid ejection device in which the liquid ejection module HU reciprocates in the X-axis direction, the present invention is not limited to this method. The liquid ejection device may also be a row-type liquid ejection device in which multiple nozzles N are distributed across the entire width of the medium PP.

[0113] 2-6. Other variations

[0114] The aforementioned liquid ejection device, besides being used in printing equipment, can also be used in various devices such as fax machines or copiers. Originally, the application of the liquid ejection device of the present invention was not limited to printing. For example, a liquid ejection device 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 device that ejects a solution of conductive material can be used as a manufacturing apparatus for wiring and electrodes in wiring boards.

[0115] Symbol Explanation

[0116] 2…Drive signal generation circuit; 5…Moving mechanism; 6…Control module; 7…Head moving mechanism; 8…Conveying mechanism; 10, 10-D, 10-E…Liquid nozzles; 14…Liquid container; 32…Connecting plate; 34…Pressure chamber base plate; 36…Vibrating plate; 42…Frame; 44…Sealing body; 46, 46-A, 46-B, 46-D, 46-E…Nozzle base plate; 48…Plastic base plate; 50…Wiring base plate; 51… Drive circuit; 71…Receiving housing; 72…Seamless strap; 100…Liquid ejection device; 322…Opening; 324…Second connecting channel; 326…First connecting channel; 328…Common flow channel; 361…Elastic membrane; 362…Insulating membrane; 422…Receiving part; 424…Inlet; CV…Pressure chamber; Com…Drive signal; D1, D1-A, D1-B, D1-D…Connecting parts; D2, D2-B, D2-D …ejection opening; DR…droplet; FN1, FN2…face; G1, G2…distance; GD1, GD1-A, GD1-B, GD1-D, GD2, GD2-B, GD2-D, GU1, GU1-E, GU2, GU2-E…center of gravity; HU…liquid ejection module; Img…printing data; L1, L2…distance; LD12, LDU, LDU-D…line segment; LG1, LG2, LG3, LG4 …distance; Ln…nozzle array; N, NA, NB, ND, NE…nozzle; ND, ND-A, ND-B, ND-D…downstream nozzle section; NU, NU-E…upstream nozzle section; PP…medium; PZ…piezoelectric element; RS…liquid storage chamber; SI…print signal; U1, U1-E…supply opening; U2, U2-E…bottom surface; WD, WU…wall surface; dCom…waveform specification signal; θ1, θ2…angle.

Claims

1. A liquid ejector head, characterized in that, have: First driving element; The first pressure chamber is divided in the pressure chamber substrate and is pressured to the liquid by the drive of the first driving element. A first nozzle, formed on a nozzle substrate and communicating with the first pressure chamber, ejects liquid. The nozzle substrate has a first surface and a second surface that is closer to the pressure chamber substrate than the first surface. The first nozzle includes: The first upstream nozzle portion includes a first supply opening that opens on the second surface and a first bottom surface that is opposite to the first supply opening; The first downstream nozzle portion includes a first ejection opening on the first surface and a first connecting portion opening on the first bottom surface. When viewed along the thickness direction of the nozzle substrate, the cross-sectional area of ​​the first upstream nozzle portion is larger than the cross-sectional area of ​​the first downstream nozzle portion. When viewed along the thickness direction, the center of gravity of the first connecting portion is located between the center of gravity of the first ejection opening and the center of gravity of the first bottom surface.

2. The liquid ejector head as described in claim 1, characterized in that, The first line segment connecting the center of gravity of the first ejection opening and the center of gravity of the first connecting portion forms a first angle greater than 0 degrees and less than 90 degrees with the thickness direction. The first downstream nozzle portion is inclined along the first line segment relative to the first surface.

3. The liquid ejector head as described in claim 1, characterized in that, When observed along the thickness direction, the center of gravity of the first ejection opening, the center of gravity of the first connecting portion, and the center of gravity of the first bottom surface are located on the same straight line.

4. The liquid ejector head as described in claim 1, characterized in that, When viewed along the thickness direction, the position of the center of gravity of the first supply opening is different from the position of the center of gravity of the first bottom surface.

5. The liquid ejector head as described in claim 2, characterized in that, It also has: The second driving element is different from the first driving element; The second pressure chamber is divided in the pressure chamber substrate and is pressured to the liquid by the drive of the second driving element; A second nozzle, formed on the nozzle substrate and communicating with the second pressure chamber, ejects liquid. The second nozzle includes: The second upstream nozzle portion includes a second supply opening on the second surface and a second bottom surface opposite to the second supply opening; The second downstream nozzle portion includes a second ejection opening on the first surface and a second connecting portion opening on the second bottom surface. When viewed along the thickness direction, the cross-sectional area of ​​the second upstream nozzle portion is larger than the cross-sectional area of ​​the second downstream nozzle portion. When viewed along the thickness direction, the center of gravity of the second connecting portion is located between the center of gravity of the second ejection opening and the center of gravity of the second bottom surface. The second angle formed by the second line segment connecting the center of gravity of the second ejection opening and the center of gravity of the second connecting part with the thickness direction is greater than 0 degrees and less than 90 degrees. The second downstream nozzle portion is inclined along the second line segment relative to the first surface. When the first angle is greater than the second angle, when viewed along the thickness direction, the distance between the center of gravity of the first bottom surface and the center of gravity of the first connecting part is longer than the distance between the center of gravity of the second bottom surface and the center of gravity of the second connecting part.

6. The liquid ejector head as described in claim 1, characterized in that, It also has: The third and fourth driving elements are different from the first driving element; The third pressure chamber is divided in the pressure chamber substrate and applies pressure to the liquid by being driven by the third driving element. A third nozzle, formed on the nozzle substrate and communicating with the third pressure chamber, ejects liquid. A fourth pressure chamber is divided in the pressure chamber substrate and is pressured to the liquid by the drive of the fourth drive element; A fourth nozzle, formed on the nozzle substrate and communicating with the fourth pressure chamber, ejects liquid. The third nozzle is located next to the first nozzle. The fourth nozzle is located next to the first nozzle and in a direction opposite to that from the first nozzle toward the third nozzle. The third nozzle includes: The third upstream nozzle portion includes a third supply opening that opens on the second surface and a third bottom surface opposite to the third supply opening; The third downstream nozzle portion includes a third ejection opening on the first surface and a third connecting portion opening on the third bottom surface. When observed along the thickness direction, the cross-sectional area of ​​the third upstream nozzle portion is larger than the cross-sectional area of ​​the third downstream nozzle portion. When viewed along the thickness direction, the center of gravity of the third connecting portion is located between the center of gravity of the third ejection opening and the center of gravity of the third bottom surface. The fourth nozzle includes: The fourth upstream nozzle portion includes a fourth supply opening on the second surface and a fourth bottom surface opposite the fourth supply opening; The fourth downstream nozzle portion includes a fourth ejection opening on the first surface and a fourth connecting portion opening on the fourth bottom surface. When observed along the thickness direction, the cross-sectional area of ​​the fourth upstream nozzle portion is larger than the cross-sectional area of ​​the fourth downstream nozzle portion. When viewed along the thickness direction, the center of gravity of the fourth connecting portion is located between the center of gravity of the fourth ejection opening and the center of gravity of the fourth bottom surface. When observed along the thickness direction, the distance from the center of gravity of the first ejection opening to the center of gravity of the third ejection opening is defined as the first distance, the distance from the center of gravity of the first ejection opening to the center of gravity of the fourth ejection opening is defined as the second distance, the distance from the center of gravity of the first bottom surface to the center of gravity of the third bottom surface is defined as the third distance, and the distance from the center of gravity of the first bottom surface to the center of gravity of the fourth bottom surface is defined as the fourth distance. The absolute value of the difference between the first distance and the second distance is less than the absolute value of the difference between the third distance and the fourth distance.

7. A liquid ejection device, characterized in that, It has a liquid ejector head as described in any one of claims 1 to 6.

8. A nozzle substrate, characterized in that, Equipped with a first nozzle for ejecting liquid, The nozzle substrate has a first surface and a second surface located on the side opposite to the first surface. The first nozzle includes: The first upstream nozzle portion includes a first supply opening that opens on the second surface and a first bottom surface that is opposite to the first supply opening; The first downstream nozzle portion includes a first ejection opening on the first surface and a first connecting portion opening on the first bottom surface. When viewed along the thickness direction of the nozzle substrate, the cross-sectional area of ​​the first upstream nozzle portion is larger than the cross-sectional area of ​​the first downstream nozzle portion. When viewed along the thickness direction, the center of gravity of the first connecting portion is located between the center of gravity of the first ejection opening and the center of gravity of the first bottom surface.

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