JP2023103569A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

To reduce a difference in discharging performance that is generated depending on whether a piezoelectric element arranged adjacently to one piezoelectric element of a plurality of piezoelectric elements is driven or not.SOLUTION: A liquid discharge head comprises: a pressure chamber substrate partitioning a first pressure chamber and a second pressure chamber which store liquid; a first driving element provided in a first direction when viewed from the pressure chamber substrate, which varies pressure in the first pressure chamber; a second driving element, arranged adjacently to the first driving element and provided in the first direction when viewed from the pressure chamber substrate, which varies pressure in the second pressure chamber; a nozzle substrate, provided in a second direction which is opposite to the first direction when viewed from the pressure chamber substrate, in which a plurality of nozzles that discharge liquid are formed, where a first cavity part that is a space that does not communicate with any nozzle of the plurality of nozzles is formed between the first pressure chamber and the second pressure chamber.SELECTED DRAWING: Figure 5

Description

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

Conventionally, a nozzle substrate having a plurality of nozzles for ejecting ink, a pressure chamber substrate having a plurality of pressure chambers communicating with each of the plurality of nozzles, and a plurality of driving elements for changing the pressure of each of the plurality of pressure chambers. is known. Also, due to pressure fluctuations in pressure chambers adjacent to pressure chambers communicating with a certain nozzle, so-called structural crosstalk occurs, in which partition walls of channels such as pressure chambers are deformed, affecting ejection of ink from certain nozzles. known to do. For example, Patent Literature 1 discloses a liquid ejection head including a layer containing silicon carbide on a wall surface facing a pressure chamber in order to suppress structural crosstalk.

JP 2021-137974 A

However, even in the above prior art, structural crosstalk occurs. Therefore, when one drive element among the plurality of drive elements is driven, there is a possibility that a difference in ejection performance may occur depending on whether or not the drive element adjacent to this one drive element is driven.

In order to solve the above problems, one aspect of the liquid ejection head according to the present invention includes: a pressure chamber substrate that separates first pressure chambers and second pressure chambers that contain liquid; a first drive element provided in the first direction for changing the pressure of the first pressure chamber; a second driving element for changing the pressure of the pressure chamber; a nozzle substrate provided in a second direction opposite to the first direction when viewed from the pressure chamber substrate and having a plurality of nozzles for ejecting liquid; and a first hollow portion, which is a space that does not communicate with any of the plurality of nozzles, is provided between the first pressure chamber and the second pressure chamber.

Another aspect of the liquid ejection head according to the present invention includes a first driving element that changes the pressure of the first pressure chamber containing the liquid, and a second driving element that changes the pressure of the second pressure chamber containing the liquid. , a communication substrate formed with a first communication channel communicating with the first pressure chamber and a second communication channel communicating with the second pressure chamber; a first nozzle communicating with the first communication channel; a nozzle substrate formed with a plurality of nozzles including a second nozzle communicating with a second communication channel, wherein a second hollow portion is provided between the first communication channel and the second communication channel. The second cavity is a space that does not communicate with any of the plurality of nozzles.

A liquid ejection apparatus according to the present invention includes a liquid ejection head and a circulation mechanism that circulates liquid supplied to the liquid ejection head.

FIG. 2 is an explanatory diagram showing an example of the liquid ejection device 100 according to the first embodiment; 2 is an exploded perspective view of the liquid ejection head 1. FIG. FIG. 3 is a cross-sectional view taken along line aa in FIG. 2; FIG. 4 is an enlarged cross-sectional view of the vicinity of the piezoelectric element PZq; The figure which expanded the vicinity of pressure chamber CB1[i]. FIG. 4 is a diagram for explaining the dimensions of the hollow portion KB1 in the X-axis direction; FIG. 11 is a diagram showing a state near pressure chamber CB1[i] in a partial drive state in a comparative example that does not have cavity KB1; FIG. 10 is a diagram showing a state near the pressure chamber CB1[i] in a fully driven state in a comparative example that does not have a hollow portion KB1; FIG. 4 is a diagram showing a state around pressure chamber CB1[i] in a partial drive state in the first embodiment; FIG. 4 is a diagram showing a state around pressure chamber CB1[i] in a fully driven state in the first embodiment; FIG. 2 is an exploded perspective view of the liquid ejection head 1b. The figure which expanded the vicinity of pressure chamber CB1[i] in 2nd Embodiment. FIG. 4 is a diagram for explaining the position of the hollow portion KR1 in the X-axis direction; The figure which expanded the vicinity of pressure chamber CB1[i] in 3rd Embodiment. The figure which expanded the vicinity of pressure chamber CB1[i] in a 1st modification. The figure which expanded the vicinity of pressure chamber CB1[i] in a 2nd modification. The figure which expanded the vicinity of pressure chamber CB1[i] in a 3rd modification. FIG. 11 is an explanatory diagram showing an example of a liquid ejection device 100g in a fifth modified example; FIG. 2 is an exploded perspective view of the liquid ejection head 1g. FIG. 20 is a cross-sectional view taken along line bb in FIG. 19; FIG. 20 is a view showing a cross section of the liquid ejection head 1h in the sixth modification taken along the line bb in FIG. 19; The figure which expanded the vicinity of pressure chamber CB1[i] in a 7th modification.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part are appropriately different from the actual ones. In addition, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are attached, but the scope of the present invention is particularly limited in the following description. It is not limited to these forms unless otherwise stated.

1. First Embodiment Hereinafter, a liquid ejecting apparatus 100 according to a first embodiment will be described with reference to FIG.

1.1. Outline of Liquid Ejecting Apparatus 100 FIG. 1 is an explanatory diagram showing an example of the liquid ejecting apparatus 100 according to the first embodiment. The liquid ejection device 100 according to the first embodiment is an inkjet printing device that ejects ink onto the medium PP. The medium PP is typically printing paper, but any print object such as a resin film or fabric can be used as the medium PP. Ink is an example of a "liquid."

As illustrated in FIG. 1, the liquid ejection device 100 includes a liquid container 93 that stores ink. As the liquid container 93, for example, a cartridge that can be attached to and detached from the liquid ejection device 100, a bag-like ink pack formed of a flexible film, or an ink tank that can be replenished with ink can be used. A plurality of types of ink with different colors are stored in the liquid container 93 .

The liquid ejecting apparatus 100 receives print data Img indicating an image to be formed by the liquid ejecting apparatus 100 and information indicating the number of prints of the image to be formed by the liquid ejecting apparatus 100 from a host computer such as a personal computer or a digital camera. , is supplied. The liquid ejecting apparatus 100 forms an image indicated by the print data Img supplied from the host computer on the medium PP.

As illustrated in FIG. 1 , the liquid ejection device 100 includes a control device 90 , a moving mechanism 91 , a transport mechanism 92 and a circulation mechanism 94 .
Among them, the control device 90 includes, for example, a processing circuit such as a CPU or FPGA, and a memory circuit such as a semiconductor memory, and controls each element of the liquid ejection device 100 . Here, CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field Programmable Gate Array.
Also, the moving mechanism 91 transports the medium PP in the Y1 direction under the control of the control device 90 . Hereinafter, the Y1 direction and the Y2 direction opposite to the Y1 direction are collectively referred to as the Y-axis direction.
Under the control of the control device 90, the transport mechanism 92 reciprocates the plurality of liquid ejection heads 1 in the X1 direction and the X2 direction opposite to the X1 direction. In addition, below, the X1 direction and the X2 direction are generically called the X-axis direction. Here, the X1 direction is a direction crossing the Y1 direction. Typically, the X1 direction is a direction perpendicular to the Y1 direction. The transport mechanism 92 includes a storage case 921 that stores a plurality of liquid ejection heads 1 and an endless belt 922 to which the storage case 921 is fixed. Note that the liquid container 93 may be stored in the storage case 921 together with the liquid ejection head 1 .
Also, under the control of the control device 90 , the circulation mechanism 94 supplies the ink stored in the liquid container 93 to the supply channel RB<b>1 provided in the liquid ejection head 1 . Furthermore, under the control of the control device 90, the circulation mechanism 94 recovers the ink stored in the discharge channel RB2 provided in the liquid ejection head 1, and circulates the recovered ink to the supply channel RB1. Let Note that the supply channel RB1 and the discharge channel RB2 will be described later with reference to FIG.

As illustrated in FIG. 1, the liquid ejection head 1 receives a drive signal Com for driving the liquid ejection head 1 and a control signal Com for controlling the liquid ejection head 1 from the control device 90 based on the print data Img. Signals SI and are provided. The liquid ejection head 1 is driven by the drive signal Com under the control of the control signal SI, and supplies the ink supplied to the supply flow path RB1 to the nozzle flow paths RN provided in the liquid ejection head 1, Ink is ejected in the Z2 direction from some or all of the M nozzles N provided in the liquid ejection head 1 . Here, the value M is an integer of 2 or more.
Also, the Z2 direction is a direction orthogonal to the X1 direction and the Y1 direction. Hereinafter, the Z2 direction and the Z1 direction opposite to the Z2 direction may be collectively referred to as the Z-axis direction. The nozzle N will be described later with reference to FIGS. 2 and 3. FIG. The nozzle flow path RN will be described later with reference to FIG.
The liquid ejection head 1 ejects ink from some or all of the M nozzles N in conjunction with the transportation of the medium PP by the moving mechanism 91 and the reciprocation of the liquid ejection head 1 by the transportation mechanism 92. By causing the ejected ink to land on the surface of the medium PP, a desired image indicated by the print data Img is formed on the surface of the medium PP.

1.2. Overview of Liquid Ejection Head 1 An overview of the liquid ejection head 1 will be described below with reference to FIGS. 2 to 4. FIG.
FIG. 2 is an exploded perspective view of the liquid ejection head 1. FIG. 3 is a sectional view taken along line aa in FIG. 2. FIG. A line aa is a virtual line segment parallel to the X axis and passing through the nozzle flow path RN.

2 and 3, the liquid ejection head 1 includes a nozzle substrate 60, a compliance sheet 61 and a compliance sheet 62, a communication substrate 2, a pressure chamber substrate 3, a vibration plate 4, and storage chambers. A substrate 5 and a wiring substrate 8 are provided. Each element of the liquid ejection head 1 is a plate-like member elongated along the Y-axis and joined together using an adhesive.

As illustrated in FIGS. 2 and 3, the nozzle substrate 60 is a plate-like member extending parallel to the XY plane, and M nozzles N are formed thereon. The nozzle substrate 60 is manufactured, for example, by processing a silicon single crystal substrate using a semiconductor manufacturing technique such as etching. However, known materials and manufacturing methods can be arbitrarily adopted for manufacturing the nozzle substrate 60 . Further, the nozzle N is a through hole provided in the nozzle substrate 60 . In this embodiment, as an example, it is assumed that M nozzles N are provided on the nozzle substrate 60 so as to form a nozzle row Ln extending in the Y-axis direction.

As illustrated in FIGS. 2 and 3 , the communication substrate 2 is provided in the Z1 direction of the nozzle substrate 60 . The communication substrate 2 is a plate-like member elongated in the Y-axis direction and extending substantially parallel to the XY plane, and forms an ink flow path.
Specifically, the communication substrate 2 is formed with one supply channel RA1 and one discharge channel RA2. Among these, the supply flow path RA1 is provided so as to communicate with the supply flow path RB1, which will be described later, and extend in the Y-axis direction. Further, the discharge flow path RA2 communicates with a discharge flow path RB2, which will be described later, and is provided so as to extend in the Y-axis direction in the X2 direction when viewed from the supply flow path RA1.
Further, the communication substrate 2 has M connection channels RK1 corresponding to the M nozzles N one-to-one, M connection channels RK2 corresponding to the M nozzles N one-to-one, M communication flow paths RR1 corresponding to M nozzles N one-to-one, M communication flow paths RR2 corresponding to M nozzles N one-to-one, and M nozzles N one-to-one 1, one connection flow path RX1 provided in common to the M nozzles N, and one connection flow path provided in common to the M nozzles N. RX2 is formed.
Note that there may be M connecting flow paths RX1 corresponding to the M nozzles N on a one-to-one basis, and there may be M connecting flow paths RX2 corresponding to the M nozzles N on a one-to-one basis. good. In the following description, it is assumed that there is one connection channel RX1 and one connection channel RX2.

Hereinafter, where m is an integer satisfying 1 or more and M or less, of the M nozzles N, the nozzle N positioned m-th as viewed along the Y2 direction may be expressed as nozzle N[m]. A communication flow path RR1 corresponding to the nozzle N[m] may be expressed as a communication flow path RR1[m]. A communication flow path RR2 corresponding to the nozzle N[m] may be expressed as a communication flow path RR2[m]. A nozzle flow path RN corresponding to a nozzle N[m] may be expressed as a nozzle flow path RN[m]. A nozzle N[m] is provided in the nozzle flow path RN[m]. The nozzle flow path RN is open in the Z2 direction and closed by the nozzle substrate 60 .

Here, the communication flow path RR1 and the communication flow path RR2 may be collectively referred to simply as the communication flow path RR when the two are not distinguished from each other. Further, hereinafter, other elements provided substantially symmetrically in the X-axis direction may be expressed using the same generic term.

The connection flow path RX1 communicates with the supply flow path RA1 and is provided so as to extend in the X-axis direction in the X2 direction when viewed from the supply flow path RA1. The connection flow path RK1 is provided so as to communicate with the connection flow path RX1 and extend in the Z-axis direction in the X2 direction when viewed from the connection flow path RX1. Further, the communication flow path RR1 is provided so as to extend in the Z-axis direction in the X2 direction when viewed from the connection flow path RK1. Further, the connection flow path RK2 is provided so as to communicate with the connection flow path RX2 and extend in the Z-axis direction in the X1 direction when viewed from the connection flow path RX2. Further, the connection flow path RX2 is provided so as to communicate with the discharge flow path RA2 and extend in the X-axis direction in the X1 direction when viewed from the discharge flow path RA2. Further, the communication flow path RR2 is provided so as to extend in the Z-axis direction in the X1 direction when viewed from the connection flow path RK2 and in the X2 direction when viewed from the communication flow path RR1. Further, the nozzle flow path RN communicates the communication flow path RR1 and the communication flow path RR2. The nozzle flow path RN is located between the pressure chambers CB1 and CB2 when viewed from the Z1 direction. The nozzle channel RN communicates with the nozzle N corresponding to the nozzle channel RN.
The communication substrate 2 is manufactured, for example, by processing a single-crystal silicon substrate using semiconductor manufacturing technology. However, known materials and manufacturing methods can be arbitrarily adopted for manufacturing the communication substrate 2 .

As illustrated in FIGS. 2 and 3 , the pressure chamber substrate 3 is provided in the Z1 direction of the communication substrate 2 . The pressure chamber substrate 3 is a plate-like member elongated in the Y-axis direction and extending substantially parallel to the XY plane, and forms an ink flow path.
Specifically, as illustrated in FIG. 2, the pressure chamber substrate 3 includes M pressure chambers CB1 corresponding to the M nozzles N one-to-one, and M nozzles N and one-to-one pressure chambers CB1. M pressure chambers CB2 corresponding to , M−1 cavity portions KB1 located between each of the M pressure chambers CB1, and M−1 located between each of the M pressure chambers CB2 A single cavity KB2 is formed. Among them, the pressure chamber CB1 is provided so as to communicate with the connection flow path RK1 and the communication flow path RR1 and extend in the X-axis direction. Further, the pressure chamber CB2 communicates with the connection flow path RK2 and the communication flow path RR2, and is provided so as to extend in the X-axis direction when viewed from the Z-axis direction. The cavity KB1 and the cavity KB2 do not communicate with any of the M nozzles N. The cavity KB1 and the cavity KB2 extend along the X-axis direction. The cavity KB1 and the cavity KB2 may be sealed or open to the atmosphere outside the liquid ejection head 1 . In the following description, the cavity KB1 and the cavity KB2 are described as closed spaces.
The pressure chamber CB1 and the pressure chamber CB2 contain ink. The cavities KB1 and KB2 do not contain ink and are filled with air.
Below, pressure chamber CB1 corresponding to nozzle N[m] may be expressed as pressure chamber CB1[m]. Pressure chamber CB2 corresponding to nozzle N[m] may be expressed as pressure chamber CB2[m]. Furthermore, when m is 1 or more and M−1 or less, the cavity KB1 provided between the pressure chambers CB1[m] and CB1[m+1] is expressed as a cavity KB1[m]. There is When m is 1 or more and M−1 or less, the cavity KB2 provided between the pressure chambers CB2[m] and CB2[m+1] may be expressed as a cavity KB2[m]. .
The pressure chamber substrate 3 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology. However, known materials and manufacturing methods can be arbitrarily adopted for manufacturing the pressure chamber substrate 3 .

As illustrated in FIG. 3, the communication flow path RR1 includes a bent portion BD1 where the direction of ink flow changes. The communication flow path RR2 includes a bent portion BD2 where the direction of ink flow changes. The bent portion BD1 is a portion of the communication flow path RR1 that overlaps the nozzle flow path RN when viewed in the X-axis direction. The bent portion BD2 is a portion of the communication flow path RR2 that overlaps the nozzle flow path RN when viewed in the X-axis direction.
Below, when m is 1 or more and M or less, the bent portion BD1 included in the communication flow path RR1 [m] may be expressed as the bent portion BD1 [m], and the communication flow path RR2 [m] The bent portion BD2 included may be expressed as a bent portion BD2[i].

In addition, hereinafter, the ink flow path that communicates with the connection flow path RX1 and the connection flow path RX2 will be referred to as a circulation flow path RJ. That is, the connection flow path RX1 and the connection flow path RX2 are communicated with the M nozzles N by the M circulation flow paths RJ corresponding to each other. As described above, each circulation flow path RJ includes a connection flow path RK1 communicating with the connection flow path RX1, a pressure chamber CB1 communicating with the connection flow path RK1, a communication flow path RR1 communicating with the pressure chamber CB1, and a communication flow path RK1 communicating with the connection flow path RX1. It includes a nozzle flow path RN that communicates with the path RR1, a communication flow path RR2 that communicates with the nozzle flow path RN, a pressure chamber CB2 that communicates with the communication flow path RR2, and a connection flow path RK2 that communicates with the pressure chamber CB2.

As illustrated in FIGS. 2 and 3, a vibration plate 4 is provided in the Z1 direction of the pressure chamber substrate 3 . The diaphragm 4 is a plate-like member elongated in the Y-axis direction and extending substantially parallel to the XY plane, and is a member capable of elastic vibration. The diaphragm 4 has, for example, an elastic film made of silicon oxide and an insulating film made of zirconium oxide, which are laminated. The elastic film is formed, for example, by thermally oxidizing one surface of a silicon single crystal substrate. The insulating film is formed, for example, by forming a zirconium layer by sputtering and thermally oxidizing the layer.

As illustrated in FIGS. 2 and 3, in the Z1 direction of the diaphragm 4, there are M piezoelectric elements PZ1 corresponding to the M pressure chambers CB1 one-to-one, and one pair corresponding to the M pressure chambers CB2. M piezoelectric elements PZ2 corresponding to 1 are provided. The piezoelectric element PZ is a passive element that deforms according to the potential change of the drive signal Com. In other words, the piezoelectric element PZ is an example of an energy conversion element that converts the electrical energy of the drive signal Com into kinetic energy.

FIG. 4 is a cross-sectional view enlarging the vicinity of the piezoelectric element PZ. However, in FIG. 4, the illustration of the protection substrate 7 is omitted in order to avoid complication of the drawing.
As illustrated in FIG. 4, the piezoelectric element PZ is a laminated body in which a piezoelectric body ZM is interposed between a lower electrode ZD supplied with a predetermined reference potential and an upper electrode ZU supplied with a drive signal Com. is. The piezoelectric element PZ is, for example, a portion where the lower electrode ZDq, the upper electrode ZU, and the piezoelectric body ZM overlap when viewed from the Z1 direction. A pressure chamber CB is provided in the Z2 direction of the piezoelectric element PZ.
As described above, the piezoelectric element PZ is driven and deformed according to the potential change of the drive signal Com. The diaphragm 4 vibrates in conjunction with the deformation of the piezoelectric element PZ. When the diaphragm 4 vibrates, the pressure inside the pressure chamber CB changes. As the pressure inside the pressure chamber CB changes, the ink filled inside the pressure chamber CB is ejected from the nozzle N via the communication channel RR and the nozzle channel RN.

As illustrated in FIGS. 2 and 3, a wiring board 8 is mounted on the surface of the diaphragm 4 in the Z1 direction. The wiring board 8 is a component for electrically connecting the control device 90 and the liquid ejection head 1 . As the wiring board 8, for example, a flexible wiring board such as FPC or FFC is preferably adopted. Here, FPC is an abbreviation for Flexible Printed Circuit, and FFC is an abbreviation for Flexible Flat Cable. A drive circuit 81 is mounted on the wiring board 8 . The drive circuit 81 is an electric circuit that switches whether to supply the drive signal Com to the piezoelectric element PZ under the control of the control signal SI. As illustrated in FIG. 4, the drive circuit 81 supplies a drive signal Com to the upper electrode ZU of the piezoelectric element PZ via the wiring 810 .
Note that, hereinafter, the drive signal Com supplied to the piezoelectric element PZ1 may be referred to as drive signal Com1, and the drive signal Com supplied to the piezoelectric element PZ2 may be referred to as drive signal Com2. In this embodiment, when ejecting ink from the nozzle N, the waveform of the drive signal Com1 supplied by the drive circuit 81 to the piezoelectric element PZ1 corresponding to the nozzle N and the waveform of the drive signal Com1 supplied to the piezoelectric element PZ2 corresponding to the nozzle N by the drive circuit 81 It is assumed that the waveform of the driving signal Com2 to be supplied is substantially the same. Here, "substantially the same" is a concept that includes not only the case of being exactly the same, but also the case of being considered to be the same if an error is considered.

Returning to FIG. 2 and FIG. As illustrated in FIG. 3, a protective substrate 7 is provided on the surface of the diaphragm 4 in the Z1 direction. The protective substrate 7 protects the M piezoelectric elements PZ1 from the outside air. Furthermore, the protective substrate 7 is a structure that reinforces the mechanical strength of the pressure chamber substrate 3 and diaphragm 4 . The protective substrate 7 has a concave portion on the surface facing the diaphragm 4 . A protective space SS is formed by fixing the protective substrate 7 to the surface of the diaphragm 4 . The protective space SS contains the piezoelectric element PZ.

As illustrated in FIGS. 2 and 3, a storage chamber forming substrate 5 is provided in the Z1 direction of the communication substrate 2 . The storage chamber forming substrate 5 is a member elongated in the Y-axis direction, and forms an ink flow path.
Specifically, one supply channel RB1 and one discharge channel RB2 are formed in the storage chamber forming substrate 5 . Among these, the supply channel RB1 is provided so as to communicate with the supply channel RA1 and extend in the Y-axis direction in the Z1 direction when viewed from the supply channel RA1. The discharge flow path RB2 communicates with the discharge flow path RA2 and extends in the Y-axis direction in the Z1 direction when viewed from the discharge flow path RA2 and in the X2 direction when viewed from the supply flow path RB1. be done.
Further, the storage chamber forming substrate 5 is provided with an inlet 51 that communicates with the supply channel RB1 and an outlet 52 that communicates with the discharge channel RB2. Ink is supplied from the liquid container 93 through the inlet 51 to the supply flow path RB1. Further, the ink stored in the discharge flow path RB2 is recovered through the discharge port 52. As shown in FIG.
An opening 50 is provided in the storage chamber forming substrate 5 . Inside the opening 50, the pressure chamber substrate 3, the diaphragm 4, and the wiring substrate 8 are provided.
The storage chamber forming substrate 5 is formed by, for example, injection molding of a resin material. However, known materials and manufacturing methods can be arbitrarily adopted for manufacturing the storage chamber forming substrate 5 .

In the first embodiment, the ink supplied from the liquid container 93 to the inlet 51 flows into the supply channel RA1 via the supply channel RB1. A part of the ink that has flowed into the supply flow path RA1 flows into the pressure chamber CB1 via the connection flow path RX1 and the connection flow path RK1. Also, part of the ink that has flowed into the pressure chamber CB1 flows into the pressure chamber CB2 via the communication flow path RR1, the nozzle flow path RN, and the communication flow path RR2. A part of the ink that has flowed into the pressure chamber CB2 is discharged from the discharge port 52 via the connection flow path RK2, the connection flow path RX2, the discharge flow path RA2, and the discharge flow path RB2.
Note that when the piezoelectric element PZ1 is driven by the drive signal Com1, part of the ink filled in the pressure chamber CB1 is discharged from the nozzle N via the communication flow path RR1 and the nozzle flow path RN. be. Further, when the piezoelectric element PZ2 is driven by the drive signal Com2, part of the ink filled inside the pressure chamber CB2 is discharged from the nozzle N via the communication flow path RR2 and the nozzle flow path RN. be.

As illustrated in FIGS. 2 and 3, a compliance sheet 61 is provided on the surface of the communication substrate 2 in the Z2 direction so as to block the supply flow path RA1, the connection flow path RX1, and the connection flow path RK1. . The compliance sheet 61 is made of an elastic material and absorbs pressure fluctuations of the ink in the supply channel RA1, the connection channel RX1, and the connection channel RK1. A compliance sheet 62 is provided on the +Z side surface of the communication board 2 so as to block the discharge channel RA2, the connection channel RX2, and the connection channel RK2. The compliance sheet 62 is made of an elastic material and absorbs pressure fluctuations of the ink in the discharge channel RA2, the connection channel RX2, and the connection channel RK2.

As described above, in the liquid ejection head 1 according to the present embodiment, the ink is discharged from the supply flow path RA1 to the discharge flow path RA2 via the connection flow path RX1, the circulation flow path RJ, and the connection flow path RX2. circulate. Therefore, in the present embodiment, even if there is a period during which the ink inside the pressure chamber CB is not ejected from the nozzle N, the ink remains stagnant inside the pressure chamber CB and in the nozzle flow path RN. can be prevented. Therefore, in the present embodiment, even if there is a period during which the ink inside the pressure chamber CB is not ejected from the nozzle N, it is possible to suppress the increase in the viscosity of the ink inside the pressure chamber CBq. It is possible to prevent the occurrence of an ejection abnormality in which ink cannot be ejected from the nozzles N due to increased viscosity.

Further, the liquid ejection head 1 according to the present embodiment can eject from the nozzles N the ink filled inside the pressure chamber CB1 and the ink filled inside the pressure chamber CB2. For this reason, in the liquid ejection head 1 according to the present embodiment, the amount of ink ejected from the nozzles N is larger than that of the nozzles N, which ejects only the ink filled in one pressure chamber CB. can be increased.

1.3. Details of Cavity KB1 FIG. 5 is an enlarged view of the vicinity of the pressure chamber CB1[i]. i is an integer of 2 or more and M−1 or less. In FIG. 5, the liquid ejection head 1 is cut along a plane that is parallel to the YZ plane and passes through the communication flow path RR1, and the cut section is viewed in the X1 direction. However, in FIG. 5, illustration of the protective substrate 7 is omitted in order to prevent complication of the drawing.

In the example of FIG. 5, the communication substrate 2 partitions the communication flow path RR1[i−1], the communication flow path RR1[i], and the communication flow path RR1[i+1]. More specifically, the communication flow path RR1[i−1] and the communication flow path RR1[i] are separated by a communication partition wall RW[i−1] which is a part of the communication substrate 2. FIG. The communication flow path RR1[i] and the communication flow path RR1[i+1] are partitioned by a communication partition wall RW[i] which is a part of the communication substrate 2 .

In the example of FIG. 5, the pressure chamber substrate 3 partitions pressure chambers CB1[i−1], CB1[i], and CB1[i+1]. The piezoelectric element PZ1[i+1] is adjacent to the piezoelectric element PZ1[i]. The piezoelectric element PZ1[i−1], the piezoelectric element PZ1[i], and the piezoelectric element PZ1[i+1] are provided in the Z1 direction when viewed from the pressure chamber substrate 3 . The nozzle substrate 60 is provided in the Z2 direction when viewed from the pressure chamber substrate 3 . Note that the Z1 direction is an example of the "first direction" and the Z2 direction is an example of the "second direction".

As illustrated in FIG. 5, the cavity KB1[i−1] is provided between the pressure chambers CB1[i−1] and CB1[i]. The cavity KB1[i] is provided between the pressure chamber CB1[i] and the pressure chamber CB1[i+1]. More specifically, the pressure chamber CB1[i−1] and the cavity KB1[i−1] are separated by a pressure chamber partition CS1[i−1] which is a part of the pressure chamber substrate 3. FIG. The cavity KB1[i−1] and the pressure chamber CB1[i] are partitioned by a pressure chamber partition CS2[i−1] which is a part of the pressure chamber substrate 3. FIG. The pressure chamber CB1[i] and the cavity KB1[i] are separated by a pressure chamber partition CS1[i] which is a part of the pressure chamber substrate 3 . The cavity KB1[i] and the pressure chamber CB1[i+1] are separated by a pressure chamber partition CS2[i] which is a part of the pressure chamber substrate 3 . In the following description, the pressure chamber partition CS1[1] to the pressure chamber partition CS1[M−1] may be collectively referred to as the pressure chamber partition CS1, and the pressure chamber partition CS2[1] to the pressure chamber partition CS2[M]. -1] may be collectively referred to as a pressure chamber partition CS2. Furthermore, the pressure chamber partition CS1 and the pressure chamber partition CS2 may be collectively referred to as the pressure chamber partition CS.

The width yKB of the cavity KB1 in the Y-axis direction is, for example, between 1 and 10 micrometers. The width between the two pressure chambers CB1 in the Y-axis direction, in other words, the sum of the width of the pressure chamber partition CS1, the width of the cavity KB1, and the width of the pressure chamber partition CS2 in the Y-axis direction is, for example, between 15 and 20 micrometers. As illustrated in FIG. 5, the width yKB is narrower than the width yCB of the pressure chamber CB1 in the Y-axis direction. The Y-axis direction is the direction in which the nozzles N are arranged, and is an example of the "nozzle row direction."

The cavity KB1 is defined by the pressure chamber substrate 3, the communication substrate 2, and the vibration plate 4. As shown in FIG. More specifically, the cavity KB1[i] is formed by the Y2-direction surface CF1 of the pressure chamber partition wall CS1[i] of the pressure chamber substrate 3 and the Y1-direction surface CF1 of the pressure chamber partition wall CS2[i] of the pressure chamber substrate 3. It is partitioned by CF2, the surface 2F1 of the communication substrate 2 in the Z1 direction, and the surface 4F2 of the diaphragm 4 in the Z2 direction. The surface 2F1 is the surface closer to the pressure chamber substrate 3 of the two surfaces of the communication substrate 2, and is an example of the "first surface." The surface 4F2 is the surface closer to the pressure chamber substrate 3 among the two surfaces of the diaphragm 4 .

The surface 2F1 and the Z2-direction surface 3F2 of the pressure chamber substrate 3 are bonded with an adhesive. The surface 3F2 is the surface closer to the nozzle substrate 60 of the two surfaces of the pressure chamber substrate 3, and is an example of the "second surface." The cavity KB1 opens toward the surface 3F1 of the pressure chamber substrate 3 in the Z1 direction, and further opens toward the surface 3F2. That is, it can be said that the cavity portion KB1 is a through hole penetrating through the pressure chamber substrate 3 .

Note that when the pressure chamber CB1[i] corresponds to the “first pressure chamber” and the pressure chamber CB1[i+1] corresponds to the “second pressure chamber”, the piezoelectric element PZ1[i] corresponds to the “first drive The piezoelectric element PZ1[i+1] corresponds to the "second driving element", the nozzle N[i] corresponds to the "first nozzle", and the nozzle N[i+1] corresponds to the "second nozzle". , the communication flow path RR1[i] corresponds to the "first communication flow path", the bent portion BD1[i] corresponds to the "first bent portion", and the communication flow path RR1[i+1] corresponds to the "second The bent portion BD1[i+1] corresponds to the “second bent portion”, and the hollow portion KB1[i] corresponds to the “first hollow portion”. Also, the pressure chamber CB1[i] can correspond to the "first pressure chamber" and the pressure chamber CB1[i-1] can correspond to the "second pressure chamber". In this case, the piezoelectric element PZ1[i] corresponds to the "first driving element", the piezoelectric element PZ1[i-1] corresponds to the "second driving element", and the nozzle N[i] corresponds to the "first nozzle". , the nozzle N[i−1] corresponds to the “second nozzle”, the communication channel RR1[i] corresponds to the “first communication channel”, and the bending portion BD1[i] corresponds to the “first The communication channel RR1[i−1] corresponds to the “second communication channel”, the curved portion BD1[i−1] corresponds to the “second curved portion”, and the hollow portion KB1 [i−1] corresponds to the “first cavity”.

FIG. 6 is a diagram for explaining the dimensions of the hollow portion KB1 in the X-axis direction. The top of FIG. 6 shows a plan view of the vicinity of the piezoelectric element PZ1[i] viewed in the Z2 direction. However, although the piezoelectric element PZ1 is normally hidden by the protective substrate 7 and cannot be seen, the piezoelectric element PZ1 is indicated by a solid line in order to make the positional relationship of the piezoelectric element PZ1 easier to see. Furthermore, the illustration of the diaphragm 4 is omitted in order to show the dimensions of the pressure chamber CB1 and the cavity KB1 in the X-axis direction. In the lower portion of FIG. 6, a view of the piezoelectric element PZ1[i] cut along a plane parallel to the XZ plane and viewed in the Y2 direction is shown.

The dimension xKB of the cavity KB1[i] in the X-axis direction is greater than or equal to the dimension xCB of the pressure chamber CB1[i] in the X-axis direction and less than or equal to the dimension xSS of the protective space SS in the x-axis direction. In the illustration of FIG. 6, dimension xKB is longer than dimension xCB and shorter than dimension xSS. Further, in the first embodiment, when viewed in the Y2 direction, the entire pressure chamber CB1 overlaps the hollow portion KB1.

The X-axis direction is a direction intersecting both the Y-axis direction and the Z1 direction, which are the directions in which the plurality of nozzles N are arranged, and is an example of the "flow path direction."

1.4. Structural Crosstalk In the first embodiment, since the cavity KB1[i] absorbs the deflection between the pressure chamber partition CS1[i] and the pressure chamber partition CS2[i], structural crosstalk is suppressed. This point will be explained. Structural crosstalk is a phenomenon in which ink ejection from a certain nozzle N is affected by deformation of the partition wall of a flow path such as a pressure chamber due to pressure fluctuations in a pressure chamber adjacent to a pressure chamber communicating with a certain nozzle N. be. In the following description, a state in which only the piezoelectric element PZ1[i] among the M piezoelectric elements PZ1 is driven is referred to as a "partially driven state," and a state in which all the M piezoelectric elements PZ1 are driven is referred to as a "fully driven state." ”. A drive signal Com supplied to the piezoelectric element PZ1 includes a drive waveform for driving the piezoelectric element PZ1. It is possible to make the drive waveforms supplied to the M piezoelectric elements PZ1 different from each other. are substantially the same. “Substantially the same” includes not only the case of being completely the same but also the case of being considered to be the same if an error is taken into account.

Structural crosstalk will be explained using the partial drive state and the full drive state. be. The ejection performance is one or both of the amount of ink ejected from the nozzle N and the ejection speed of the ink ejected from the nozzle N. In this embodiment, the ejection performance is described as the ejection amount of ink ejected from the nozzles N. As shown in FIG. In order to explain why structural crosstalk is suppressed by the cavity KB1, structural crosstalk in a mode without the cavity KB1 will be described with reference to FIGS. 7 and 8. FIG.

FIG. 7 is a diagram showing the state of the vicinity of the pressure chamber CB1[i] in the partially driven state in a comparative example that does not have the hollow portion KB1 unlike the present embodiment. The comparative example differs from the first embodiment in that it has a pressure chamber substrate 3 a instead of the pressure chamber substrate 3 . The pressure chamber substrate 3a does not have the cavity KB1 and the cavity KB2. In the comparative example, a pressure chamber partition CW that is part of the pressure chamber substrate 3 is provided between the two pressure chambers CB1. In the following description, the pressure chamber partition CW provided between the pressure chambers CB1[i] and CB1[i+1] may be expressed as pressure chamber partition CW[i]. In FIG. 7, a droplet DR1[i] ejected from the nozzle N[i] is shown to indicate the partial drive state.

As illustrated in FIG. 7, when the piezoelectric element PZ1[i] is driven, the piezoelectric element PZ1[i] is deformed and the pressure in the pressure chamber CB1[i] changes. Due to the pressure change in the pressure chamber CB1[i], a stress σ1[i] in the Y2 direction is generated in the pressure chamber partition CW[i−1]. It bends in the Y2 direction. Furthermore, due to the pressure change in the pressure chamber CB1[i], a stress σ2[i] in the Y1 direction is generated in the pressure chamber partition CW[i]. bend. Furthermore, due to the pressure change in the pressure chamber CB1[i], a stress σ3[i] in the Y2 direction is generated in the communication partition RW[i−1], and the stress σ3[i] causes the communication partition RW[i−1] to It bends in the Y2 direction. Furthermore, due to the pressure change in the pressure chamber CB1[i], a Y1-direction stress σ4[i] is generated in the communication partition RW[i], and the communication partition RW[i] bends in the Y1 direction.

As described above, in the comparative example, the excluded volume ΔW1 between the pressure chamber CB1[i] and the communication flow path RR1[i] in the partial drive state is the pressure chamber partition CW[i−1], the pressure chamber partition CW[i], It decreases as the communication partition RW[i−1] and the communication partition RW[i] bend. The excluded volume means the amount of change in volume between the pressure chamber CB1[i] and the communication flow path RR1[i] due to the vibration of the diaphragm 4. FIG.

FIG. 8 is a diagram showing the state near the pressure chamber CB1[i] in the full drive state in the comparative example. In FIG. 8, to show the full drive state, a droplet DR2[i−1] ejected from the nozzle N[i−1] and a droplet DR2[i] ejected from the nozzle N[i] , and a droplet DR2[i+1] ejected from the nozzle N[i+1].

As illustrated in FIG. 8, driving all of the piezoelectric elements PZ1 deforms all of the piezoelectric elements PZ1, thereby changing the pressures of all the pressure chambers CB1. A stress σ2[i−1] in the Y1 direction is generated in the pressure chamber partition CW[i−1] due to the pressure change in the pressure chamber CB1[i−1]. Furthermore, due to the pressure change in the pressure chamber CB1[i], a stress σ1[i] in the Y2 direction is generated in the pressure chamber partition CW[i−1]. Therefore, since the stress σ2[i−1] and the stress σ1[i] acting in different directions cancel each other, the pressure chamber partition CW[i−1] does not bend.

A stress σ2[i] in the Y1 direction is generated in the pressure chamber partition CW[i] due to the pressure change in the pressure chamber CB1[i]. Furthermore, due to the pressure change in the pressure chamber CB1[i+1], a stress σ1[i] in the Y2 direction is generated in the pressure chamber partition wall CW[i]. Therefore, since the stress σ2[i] and the stress σ1[i+1] acting in different directions cancel each other, the pressure chamber partition CW[i] does not bend.

A stress σ4[i−1] in the Y1 direction is generated in the communication partition RW[i−1] due to the pressure change in the pressure chamber CB1[i−1]. Furthermore, due to the pressure change in the pressure chamber CB1[i], a stress σ3[i] in the Y2 direction is generated in the communication partition RW[i−1]. Therefore, since the stress σ4[i−1] and the stress σ3[i] acting in different directions cancel each other, the communication partition RW[i−1] does not bend.

A stress σ4[i] in the Y1 direction is generated in the communication partition RW[i] due to the pressure change in the pressure chamber CB1[i]. Furthermore, due to the pressure change in the pressure chamber CB1[i+1], a stress σ3[i+1] in the Y2 direction is generated in the communication partition RW[i]. Therefore, since the stress σ4[i] and the stress σ3[i+1] acting in mutually different directions cancel each other, the communication partition RW[i] does not bend.

As described above, in the comparative example, the excluded volume ΔW2 between the pressure chamber CB1[i] and the communication flow path RR1[i] in the full drive state is the pressure chamber partition CS[i−1], the pressure chamber partition CS[i], Since the communication partition RW[i−1] and the communication partition RW[i] do not bend, the displacement volume is larger than that between the pressure chamber CB1[i] and the communication flow path RR1[i] in the partial drive state. 7 and 8, the magnitude relationship between the ejection amount from the nozzle N in the partial drive state and the ejection amount from the nozzle N in the full drive state is shown between the droplet DR1[i] and the droplet DR2[i]. expressed in terms of size. As illustrated in FIGS. 7 and 8, droplet DR2[i] is larger than droplet DR1[i]. The droplet DR2[i] becoming larger than the droplet DR1[i] is not what is shown in the print data Img, but is a phenomenon unintended by the user. When structural crosstalk occurs, the image formed on the surface of the medium PP is different from the image indicated by the print data Img, so the image quality of the image formed on the surface of the medium PP is degraded.

A difference ΔD1 between the volume of the droplet DR2[i] and the volume of the droplet DR1[i] is expressed by the following formula (1).
ΔD1 = ΔW2 - ΔW1 (1)

Equation (1) can be rephrased as Equation (2) below.
ΔD1=ΔCS[i−1]+ΔCS[i]+ΔRW[i−1]+ΔRW[i] (2)

However, ΔCS[i−1] indicates the amount of change in the volume of the pressure chamber CB1[i] due to the deflection of the pressure chamber partition CS[i−1]. ΔCS[i] indicates the amount of change in the volume of the pressure chamber CB1[i] due to the deflection of the pressure chamber partition CS[i]. ΔRW[i−1] indicates the amount of change in the volume of the communication flow path RR1[i] due to the deflection of the communication partition RW[i−1]. ΔRW[i] indicates the amount of change in the volume of the communication flow path RR1[i] due to the deflection of the communication partition RW[i]. ΔCS[i−1], ΔCS[i], ΔRW[i−1], and ΔRW[i] are all positive values.

Next, the reason why structural crosstalk is suppressed by the hollow portion KB1 will be described with reference to FIGS. 9 and 10. FIG.

FIG. 9 is a diagram showing a state near the pressure chamber CB1[i] in the partial drive state in the first embodiment. In FIG. 9, a droplet DR3[i] ejected from the nozzle N[i] is shown to indicate the partial drive state.

As illustrated in FIG. 9, driving the piezoelectric element PZ1[i] deforms the piezoelectric element PZ1[i] and changes the pressure in the pressure chamber CB1[i]. Due to the pressure change in the pressure chamber CB[i], the pressure chamber partition CS2[i−1] bends in the Y1 direction, and the pressure chamber partition CS1[i] bends in the Y1 direction. Since the air filled in the cavity KB1[i−1] is gas, it is compressed by external stress. The air in the cavity KB1[i-1] is compressed and the pressure in the cavity KB1[i-1] rises, but not to the extent that the pressure chamber partition CS2[i-1] is significantly deformed. Similarly, the air in the cavity KB1[i] is compressed and the pressure in the cavity KB1[i] rises, but not to the extent that the pressure chamber partition CS2[i] is significantly deformed. In this way, even if one of the two pressure chamber partition walls CS defining the cavity KB1 is flexed due to a change in the pressure of the pressure chamber CB1, the air inside the cavity KB1 is compressed. For example, since the hollow portion KB1 absorbs the bending of one pressure chamber partition CS, it is possible to suppress the bending of the other pressure chamber partition CS.
Note that in a mode in which the cavity KB1 is open to the atmosphere outside the liquid ejection head 1, the pressure chamber partition CS1[i] bends in the Y1 direction, and the volume of the cavity KB1[i] shrinks. However, the pressure in the cavity KB1[i] does not change. Therefore, in the mode in which the cavity KB1 is open to the atmosphere outside the liquid ejection head 1, compared to the mode in which the cavity KB1 is closed to the atmosphere outside the liquid ejection head 1, the pressure The chamber partition CS2[i] can not be deformed.

A stress σ3[i] in the Y2 direction is generated in the communication partition RW[i−1] due to the pressure change in the pressure chamber CB1[i], and the stress σ3[i] causes the communication partition RW[i−1] to move in the Y2 direction. bend toward. Furthermore, due to the pressure change in the pressure chamber CB1[i], a Y1-direction stress σ4[i] is generated in the communication partition RW[i], and the communication partition RW[i] bends in the Y1 direction.

As described above, in the first embodiment, the excluded volume ΔW3 between the pressure chamber CB1[i] and the communication passage RR1[i] in the partial drive state is determined by the pressure chamber partition CS[i−1], the pressure chamber partition CS[i ], communication partition RW[i−1], and communication partition RW[i].

FIG. 10 is a diagram showing the state around the pressure chamber CB1[i] in the full drive state in the first embodiment. In FIG. 10, to indicate the full drive state, a droplet DR4[i−1] ejected from the nozzle N[i−1] and a droplet DR4[i] ejected from the nozzle N[i] , and a droplet DR4[i+1] ejected from the nozzle N[i+1].

As illustrated in FIG. 10, driving all of the piezoelectric elements PZ1 deforms all of the piezoelectric elements PZ1, and the pressures of all the pressure chambers CB1 change. A stress σ2[i−1] in the Y1 direction is generated in the pressure chamber partition CS1[i−1] due to the pressure change in the pressure chamber CB1[i−1]. Moreover, due to the pressure change in the pressure chamber CB1[i], a stress σ1[i] in the Y2 direction is generated in the pressure chamber partition CS2[i−1]. Since the air filled in the cavity KB1[i−1] is gas, it is compressed by external stress. The air filled in the cavity KB1[i−1] is compressed, the pressure chamber partition CS1[i−1] bends in the Y1 direction, and the pressure chamber partition CS1[i−1] bends in the Y2 direction. nothing. Similarly, the air filled in the cavity KB1[i] is compressed, and the stress σ2[i] in the Y1 direction bends the pressure chamber partition CS1[i−1] in the Y1 direction, causing the stress σ1[i] in the Y2 direction. i+1] causes the pressure chamber partition CS1[i−1] to bend in the Y2 direction.

Since the communication partition RW[i−1] and the communication partition RW[i] are the same as those in FIG. 8, the description thereof is omitted.

As described above, in the first embodiment, the excluded volume ΔW4 between the pressure chamber CB1[i] and the communication passage RR1[i] in the full drive state is determined by the pressure chamber partition CS[i−1] and the pressure chamber partition CS [i] is reduced by the bending amount. Also in the first embodiment, the displacement volume between the pressure chamber CB1[i] and the communication flow path RR[i] in the full drive state is Since it does not bend, it is larger than the excluded volume between the pressure chamber CB1[i] and the communication flow path RR1[i] in the partial drive state. 9 and 10, the magnitude relationship between the ejection amount from the nozzle N in the partial drive state and the ejection amount from the nozzle N in the full drive state is shown between the droplet DR3[i] and the droplet DR4[i]. expressed in terms of size. As illustrated in FIGS. 9 and 10, droplet DR4[i] is larger than droplet DR3[i]. However, the difference between the size of the droplet DR4[i] and the size of the droplet DR3[i] is smaller than the difference between the size of the droplet DR2 and the size of the droplet DR[1].

A comparison will be made between the first embodiment and a mode that does not have the cavity portion KB1. In the embodiment without the hollow portion KB1, the difference in displacement volume between the partial drive state and the full drive state is the pressure chamber partition CS[i−1], the pressure chamber partition CS[i], the communication partition RW[i−1 ] and the bending of the communication partition RW[i]. On the other hand, in the first embodiment, the difference in displacement volume between the partial drive state and the full drive state corresponds to the bending of the communication partition RW[i−1] and the communication partition RW[i]. Therefore, in the first embodiment, compared to the comparative example, the pressure chamber partition CS[i−1] and the pressure chamber partition CS[i] are bent in both the partial drive state and the full drive state, so the difference in displacement volume is suppressed. that is, structural crosstalk can be suppressed.

Using the difference ΔD1 between the volume of the droplet DR2[i] and the volume of the droplet DR1[i] and the difference ΔD2 between the volume of the droplet DR4[i] and the volume of the droplet DR3[i], The reason why structural crosstalk can be suppressed in one embodiment will be described. The difference ΔD2 is expressed by the following formula (3).

ΔD2=ΔW4−ΔW3 (3)

Equation (3) can be rephrased as Equation (4) below.
ΔD2=ΔRW[i−1]+ΔRW[i] (4)

Comparing the droplet volume difference ΔD1 between the full drive state and the partial drive state in the comparative example with the droplet volume difference ΔD2 between the full drive state and the partial drive state in the first embodiment, the following (5 ) is obtained.

ΔD2-ΔD1 (5)

Equation (5) can be transformed into Equation (6) below using Equations (2) and (4).
(ΔRW[i−1]+ΔRW[i])−(ΔCS[i−1]+ΔCS[i]+ΔRW[i−1]+ΔRW[i])
=-ΔCS[i-1]-ΔCS[i] (6)

Both ΔCS[i−1] and ΔCS[i] are positive values. Therefore, equations (5) and (6) show negative values. As described above, the droplet volume difference ΔD2 between the full drive state and the partial drive state in the first embodiment is smaller than the droplet volume difference ΔD1 between the full drive state and the partial drive state in the comparative example. That is, structural crosstalk can be suppressed.

1.5. Summary of First Embodiment As described above, the liquid ejection head 1 includes the pressure chamber substrate 3, the piezoelectric elements PZ1[i], the piezoelectric elements PZ1[i+1], and the nozzle substrate 60. FIG. The pressure chamber substrate 3 partitions the pressure chamber CB1[i] and the pressure chamber CB1[i+1] that contain ink. The piezoelectric element PZ1[i] is provided in the Z1 direction when viewed from the pressure chamber substrate 3, and changes the pressure of the pressure chamber CB1[i]. The piezoelectric element PZ1[i+1] is adjacent to the piezoelectric element PZ1[i], is provided in the first direction when viewed from the pressure chamber substrate 3, and changes the pressure of the pressure chamber CB1[i+1]. The nozzle substrate 60 is provided in the Z2 direction when viewed from the pressure chamber substrate 3, and has a plurality of nozzles N for ejecting ink. Between the pressure chambers CB1[i] and CB1[i+1], a cavity KB1[i], which is a space that does not communicate with any of the plurality of nozzles N, is provided.
According to the first embodiment, the hollow portion KB1[i] absorbs the deflection of the pressure chamber partition CS1[i] and the pressure chamber partition CS1[i+1] regardless of whether it is in the partial drive state or the full drive state. , structural crosstalk is suppressed. By suppressing the structural crosstalk, the image quality of the image formed on the medium PP can be improved.

Further, in the Y-axis direction, the width of the hollow portion KB1[i] is narrower than the width of the pressure chambers CB1[i] and the width of the pressure chambers CB1[i+1].
According to the first embodiment, the width of the cavity KB1[i] is wider than the width of the pressure chamber CB1[i] and the width of the pressure chamber CB1[i+1]. It can be arranged in high density, and the resolution can be improved.

The multiple nozzles N include a nozzle N[i] communicating with the pressure chamber CB1[i] and a nozzle N[i+1] communicating with the pressure chamber CB1[i+1]. A communication substrate 2 is provided between the pressure chamber substrate 3 and the nozzle substrate 60 to partition the communication flow path RR1[i] and the communication flow path RR1[i+1]. The communication channel RR1[i] communicates between the pressure chamber CB1[i] and the nozzle N[i]. The communication channel RR1[i] communicates between the pressure chamber CB1[i+1] and the nozzle N[i+1]. The cavity KB1[i] is defined by the pressure chamber substrate 3 and a surface 2F1 of the two surfaces of the communication substrate 2 that is closer to the pressure chamber substrate 3. As shown in FIG.
According to the first embodiment, since the cavity KB1[i] is defined by the surface 2F1 of the communication substrate 2, the cavity KB1[i] is not defined by the surface 2F1, in other words, the cavity KB1[i] is not defined by the surface 2F1. i] in the Z-axis direction is shorter than the width of the pressure chamber substrate 3, the deformation of the pressure chamber partition CS can be absorbed more easily.

Further, the surface 2F1 and the surface 3F2 of the pressure chamber substrate 3 are bonded with an adhesive.
This adhesive also flows into the cavity KB1[i]. By flowing the adhesive into the cavity KB1[i], it is possible to suppress the adhesive from flowing into one or both of the pressure chamber CB1 and the communication flow path RR1. When the adhesive flows into the pressure chamber CB1, the adhesive accumulates at the boundary between the pressure chamber partition CS and 4F2, hindering the deformation of the vibration plate 4 and reducing the ink discharge amount. Therefore, according to the first embodiment, the amount of ink ejected is less likely to decrease compared to an aspect having no hollow portion KB1[i], so a decrease in ejection performance can be suppressed.

The liquid ejection head 1 also includes a vibration plate 4 provided between the pressure chamber substrate 3 and the piezoelectric element PZ1[i]. The cavity KB1[i] is defined by the pressure chamber substrate 3 and the surface 4F2 of the diaphragm 4. As shown in FIG.
According to the first embodiment, since the cavity KB1[i] is defined by the surface 4F2 of the diaphragm 4, the cavity KB1[i] is not defined by the surface 4F2. i] in the Z-axis direction is shorter than the width of the pressure chamber substrate 3, the deformation of the pressure chamber partition CS can be absorbed more easily.

The dimension of the cavity KB1 in the X-axis direction is greater than or equal to the dimensions of the pressure chambers CB1[i] and CB1[i+1] in the X-axis direction.
In a mode in which the dimension of the cavity KB1[i] in the X-axis direction is smaller than the dimension of the pressure chamber CB1[i] and the pressure chamber CB1[i+1] in the X-axis direction, the cavity KB1[i] There are places where the deflection of the partition due to the pressure change in [i] cannot be absorbed. More specifically, when the pressure chamber substrate 3 is viewed from the Y-axis direction, the partition wall 10 is formed by pressure changes in the pressure chambers CB1[i] at locations where the pressure chambers CB1[i] do not overlap the cavity portions KB1[i]. It is more likely that it will not be able to absorb the deflection of the Therefore, according to the first embodiment, it is possible to suppress the possibility that the deformation of the partition due to the pressure change in the pressure chamber CB1[i] cannot be absorbed. Furthermore, in the first embodiment, when the pressure chamber substrate 3 is viewed from the Y-axis direction, all of the pressure chambers CB1[i] overlap with the cavity portions KB1[i]. Therefore, in the first embodiment, when the pressure chamber substrate 3 is viewed from the Y-axis direction, the pressure chamber CB1[i] does not overlap the cavity KB1[i]. The deflection of the partition due to the pressure change of [i] can be absorbed more.

The liquid ejection apparatus 100 also includes the liquid ejection head 1 and a circulation mechanism 94 that circulates the ink supplied into the liquid ejection head 1 .
According to the first embodiment, air bubbles and dust mixed in the ink are returned to the circulation mechanism 94 together with the circulating ink, so clogging of the nozzles N is reduced. Therefore, maintenance such as liquid replacement and cleaning of the liquid ejection head 1 is facilitated.

2. Second Embodiment In the first embodiment, the cavity KB1[i] is provided between the pressure chamber CB1[i] and the pressure chamber CB1[i+1]. The second embodiment differs from the first embodiment in that a cavity is also provided between the communication flow paths RR1[i] and RR1[i]. A second embodiment will be described below.

2.1. Overview of Liquid Ejection Head 1b in Second Embodiment FIG. 11 is an exploded perspective view of the liquid ejection head 1b. A liquid ejection head 1 b in the second embodiment differs from the liquid ejection head 1 in that it has a communication substrate 2 b instead of the communication substrate 2 . The communication substrate 2b differs from the communication substrate 2 in that it has a cavity KR1 between two communication flow paths RR1 and a cavity KR2 between two communication flow paths RR2 in the Y-axis direction. In the following, when m is 1 or more and M−1 or less, the cavity KR1 provided between the communication flow path RR1[m] and the communication flow path RR1[m+1] is referred to as the cavity KR1[m]. can be expressed. When m is 1 or more and M−1 or less, the cavity KR2 provided between the communication channel RR2[m] and the communication channel RR2[m+1] is expressed as the cavity KR2[m]. There is

When the pressure chamber CB1[i] corresponds to the "first pressure chamber" and the pressure chamber CB1[i+1] corresponds to the "second pressure chamber", the cavity KR1[i] is the "second cavity". corresponds to Further, when the pressure chamber CB1[i] corresponds to the "first pressure chamber" and the pressure chamber CB1[i-1] corresponds to the "second pressure chamber", the cavity KR1[i-1] is It corresponds to the "second cavity".

The cavity KR1 and the cavity KR2 do not communicate with any of the M nozzles N. The cavity KR1 and the cavity KB2 may be sealed or open to the atmosphere outside the liquid ejection head 1b. In the following description, it is assumed that the liquid ejection head 1b is sealed against the atmosphere outside. The cavities KR1 and KR2 do not contain ink and are filled with air.

FIG. 12 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the second embodiment. i is an integer of 2 or more and M−1 or less. In FIG. 12, the liquid ejection head 1b is cut along a plane that is parallel to the YZ plane and passes through the communication flow path RR1, and the cut section is viewed in the X1 direction. However, in FIG. 12, illustration of the protective substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 12, the cavity KR1[i-1] is provided between the communication flow path RR1[i-1] and the communication flow path RR1[i]. The cavity KR1[i] is provided between the communication flow path RR1[i] and the communication flow path RR1[i+1]. More specifically, the communication flow path RR1[i-1] and the cavity KR1[i-1] are separated by a communication partition wall RS1[i-1] that is part of the communication substrate 2b. The cavity KR1[i-1] and the communication flow path RR1[i] are separated by a communication partition wall RS2[i-1] which is a part of the communication substrate 2b. The communication flow path RR1[i] and the cavity KR1[i] are separated by a communication partition RS1[i] that is part of the communication substrate 2b. The cavity KR1[i] and the communication flow path RR1[i+1] are separated by a communication partition wall RS2[i] that is part of the communication substrate 2b. In the following description, the communication partition RS1[1] to the communication partition RS1[M-1] may be collectively referred to as the communication partition RS1, and the communication partition RS2[1] to the communication partition RS2[M-1]. , and communication partition RS2. Furthermore, the communication partition RS1 and the communication partition RS2 may be collectively referred to as the communication partition RS.

The cavity KR1 is defined by the communication substrate 2b and the surface 6F1 of the nozzle substrate 60 in the Z1 direction. More specifically, the cavity KR1[i] is defined by the Y2-direction surface RF1 of the communication partition RS1[i] and the Y1-direction surface RF2 of the communication partition RS2[i]. The surface 6F1 is the surface closer to the pressure chamber substrate 3 of the two surfaces of the nozzle substrate 60, and is an example of the "third surface."

As illustrated in FIG. 12, the width yKR of the cavity KR1 in the Y-axis direction is narrower than the width yKB of the cavity KB1 in the Y-axis direction. Further, as can be understood from FIG. 12, the hollow portion KB1[i] and the hollow portion KR1[i] overlap when viewed in the Z-axis direction. Here, the hollow portion KB1[i] and the hollow portion KR1[i] overlap means that part or all of the hollow portion KB1[i] and part or all of the hollow portion KR1[i] overlap. means In the illustration of FIG. 12, all of the cavity KB1[i] overlaps a part of the cavity KR1[i] when viewed in the Z-axis direction.

The cavity KR1 opens toward the Z1-direction surface 2F1 of the communication substrate 2b, and further opens toward the Z2-direction surface 2F2 of the communication substrate 2b. That is, it can also be said that the hollow portion KR1 is a through hole penetrating the communication substrate 2b. The surface 2F2 is the surface closer to the nozzle substrate 60 among the two surfaces of the communication substrate 2b.

FIG. 13 is a diagram for explaining the position of the hollow portion KR1 in the X-axis direction. The upper part of FIG. 13 shows a plan view of the vicinity of the communication flow path RR1[i] of the communication substrate 2b as viewed in the Z2 direction. The lower portion of FIG. 13 shows a cross-sectional view of the liquid ejection head 1b cut along a plane parallel to the XZ plane passing through the communication flow path RR1[i] and viewed in the Y2 direction.

The dimension xKR of the hollow portion KR1[i] in the X-axis direction is greater than or equal to the dimension xRR of the communication flow path RR1[i] in the X-axis direction. In the illustration of FIG. 13, dimension xKR is longer than dimension xRR.

Furthermore, as understood from FIG. 13, the cavity KR1[i] is provided between the bending portion BD1[i] and the bending portion BD1[i+1].

2.2. Summary of Second Embodiment As described above, the cavity KR1[i] is provided between the communication flow path RR1[i] and the communication flow path RR2[i+1]. The cavity KR[i] is a space that does not communicate with any of the nozzles N among the plurality of nozzles N. As shown in FIG.
According to the second embodiment, since the cavity KR1[i] absorbs the flexure of the communication partition RS1[i] and the communication partition RS2[i], structural crosstalk is reduced more than in the first embodiment. can be suppressed. Further, the adhesive that bonds the surface 2F1 of the communication substrate 2 and the surface 3F2 of the pressure chamber substrate 3 enters not only the cavity KB1[i] but also the cavity KR1[i]. Therefore, according to the second embodiment, it is possible to suppress the change in the pressure loss of the ink as compared with the first embodiment.

Also, when viewed in the Z1 direction, the cavity KB1[i] and the cavity KR1[i] overlap. That is, the pressure chamber partition CS1[i] and the communication partition RS1[i] are not joined to the pressure chamber partition CS2[i] and the communication partition RS2[i].
A mode in which the cavity KB1[i] and the cavity KR1[i] do not overlap when viewed in the Z1 direction is a mode in which a portion of the pressure chamber partition CS1[i] joins a portion of the communication partition RS2[i]. , a portion of the pressure chamber partition CS2[i] is joined to a portion of the communication partition RS1[i]. Hereinafter, a description will be given using a mode in which a portion of the pressure chamber partition CS1[i] is joined to a portion of the communication partition RS2[i]. Due to the pressure change in the pressure chamber CB1[i+1], the communication partition RS2[i] bends in the Y1 direction. A stress in the Y1 direction is generated in the pressure chamber partition CS1[i] depending on the portion. Therefore, in the full drive state, the stress in the Y2 direction and the stress in the Y1 direction are generated in the pressure chamber partition CS1[i]. smaller in comparison.
On the other hand, in the second embodiment, the pressure chamber partition CS1[i] and the communication partition RS1[i] are not joined to the pressure chamber partition CS2[i] and the communication partition RS2[i]. No stress in the Y1 direction is generated in the pressure chamber partition CS1[i]. Therefore, according to the second embodiment, structural crosstalk can be suppressed compared to a mode in which the cavity KB1[i] and the cavity KR1[i] do not overlap when viewed in the Z1 direction.

Further, the width of the cavity KR1[i] in the Y-axis direction is greater than the width of the cavity KB1[i].

Cavity KR1[i] opens toward surface 2F2 of communication substrate 2b.
According to the second embodiment, the adhesive that joins the communication substrate 2b and the nozzle substrate 60 flows into the cavity KR1 through the opening provided on the surface 2F2. By flowing the adhesive into the cavity KR1[i], it is possible to suppress the adhesive from flowing into one or both of the communication channel RR1 and the nozzle channel RN. When the adhesive flows into the communication flow path RR1 or the nozzle flow path RN, the shape of the communication flow path RR1 or the nozzle flow path RN changes, and the pressure loss of the ink changes. If the pressure loss of the ink changes, there is a possibility that the ejection performance will deteriorate as described above. Therefore, according to the second embodiment, the ink pressure loss is less likely to change compared to the case where the cavity KR1[i] does not open toward the surface of the communication substrate 2b, so the ejection performance is lowered. can be suppressed.

The communication channel RR1[i] includes a bent portion BD1[i] where the direction of ink flow changes. The communication flow path RR1[i+1] includes a bent portion BD1[i+1] where the direction of ink flow changes. Cavity KR1[i] is provided between bending portion BD1[i] and bending portion BD1[i+1]. When viewed from the Y-axis direction, the hollow portion KR1[i] overlaps the bent portion BD1[i] and the bent portion BD1[i+1].
In the communication flow path RR1[i], the partition wall of the bent portion BD1[i] is more flexible than the partition wall of the remaining portion. Therefore, by providing the hollow portion KR1[i] between the bending portion BD1[i] and the bending portion BD1[i+1], the bending of the partition between the bending portion BD1[i] and the bending portion BD1[i+1] can be absorbed, and structural crosstalk can be suppressed compared to a mode in which the cavity KR1[i] is not between the bent portion BD1[i] and the bent portion BD1[i+1].

3. Third Embodiment In the second embodiment, the pressure chamber substrate 3 is provided with the cavity portions KB1 and KB2, and the communication substrate 2b is provided with the cavity portions KR1 and KR2. On the other hand, the third embodiment differs from the second embodiment in that the pressure chamber substrate 3 is not provided with the cavity portions KB1 and KB2, and the communication substrate 2b is provided with the cavity portions KR1 and KR2. . A third embodiment will be described below.

3.1. Overview of Liquid Ejection Head 1c in Third Embodiment FIG. 14 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the third embodiment. i is an integer of 2 or more and M−1 or less. In FIG. 14, the liquid ejection head 1c is cut along a plane that is parallel to the YZ plane and passes through the communication flow path RR1, and the cut section is viewed in the X1 direction. However, in FIG. 14, illustration of the protection substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 14, the liquid ejection head 1c differs from the liquid ejection head 1b in that instead of the pressure chamber substrate 3, it has a pressure chamber substrate 3a.

The liquid ejection head 1c includes a piezoelectric element PZ1[i], a piezoelectric element PZ1[i+1], a communication substrate 2b, and a nozzle substrate 60. As shown in FIG. The piezoelectric element PZ1[i] changes the pressure of the pressure chamber CB1[i] containing ink. The piezoelectric element PZ1[i+1] changes the pressure of the pressure chamber CB1[i+1] containing ink. A communication flow path RR1[i] communicating with the pressure chamber CB1[i] and a communication flow path RR1[i+1] communicating with the pressure chamber CB1[i+1] are formed in the communication substrate 2b. The nozzle substrate 60 is formed with a plurality of nozzles N including a nozzle N[i] communicating with the communication channel RR1[i] and a nozzle N[i] communicating with the communication channel RR1[i+1]. A hollow portion KR1[i] is provided between the communication flow path RR1[i] and the communication flow path RR1[i+1]. The cavity KR1[i] is a space that does not communicate with any of the nozzles N among the plurality of nozzles.
According to the third embodiment, the hollow portion KR1[i] absorbs the flexure of the communication partition RS1[i] and the communication partition RS1[i+1] regardless of the partial drive state or the full drive state. Talk is suppressed.

4. Modifications Each of the forms illustrated above can be modified in various ways. Some examples of specific modification modes are illustrated below. Two or more aspects arbitrarily selected from the following examples can be combined as appropriate within a mutually consistent range.

4.1. First Modification In the second or third embodiment, the hollow portion KR1 is a through hole penetrating the communication substrate 2b, but it may be a concave portion that does not penetrate.

FIG. 15 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the first modified example. i is an integer of 2 or more and M−1 or less. FIG. 15 shows a view of the liquid ejection head 1d in the first modification taken along a plane parallel to the YZ plane and passing through the communication flow path RR1, and looking at the cross section in the X1 direction. However, in FIG. 15, the illustration of the protection substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 15, the liquid ejection head 1d differs from the liquid ejection head 1b in that it has a communication substrate 2d instead of the communication substrate 2b. The communication substrate 2d differs from the communication substrate 2b in that it has a hollow portion KRd1 provided between two adjacent communication flow paths RR1.

The cavity KRd1 opens toward the surface 2F1 but does not open toward the surface 2F2. Therefore, it can also be said that the cavity KRd1 is a recess that is recessed in the Z2 direction. Using the cavity KRd1[i] to explain that it is a recess, the deepest part of the cavity KRd1[i] when viewed from the surface 2F1 is the communication channel RR1[i] and the communication channel RR1[i]. Shallow compared to RR1[i+1]. Specifically, the length zKR in the Z-axis direction from the surface 2F1 to the deepest part of the cavity KRd1[i] is the length in the Z-axis direction of the communication flow path RR1[i] and the communication flow path RR1[i+1]. shorter than zRR.
According to the first modified example, compared to the second embodiment in which the cavity KR1 is opened on both sides, the strength of the communication board 2d is increased, and thus the manufacturing of the liquid ejection head 1d is facilitated. Further, according to the first modified example, compared to the aspect in which the cavity KR1 opens toward the surface 2F2 and does not open toward the surface 2F1, the pressure chamber partition walls CS1[i] and the pressure chamber partitions CS1[i] and Since the communication partition wall RS1[i] is not joined to the pressure chamber partition wall CS2[i] and the communication partition wall RS2[i], deformation of the communication flow path RR1 can be easily absorbed, and structural crosstalk can be suppressed.

In the first modified example, the communication substrate 2d has the hollow portion KRd1, which is a concave portion, between two adjacent communication flow paths RR1. It may have a cavity KR2 which is

4.2. Second Modification In the first embodiment, the second embodiment, and the first modification, the cavity KB1 was a through hole penetrating the pressure chamber substrate 3. good.

FIG. 16 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the second modified example. i is an integer of 2 or more and M−1 or less. FIG. 16 shows a view of the liquid ejection head 1e in the second modification taken along a plane parallel to the YZ plane and passing through the communication flow path RR1, and looking at the cross section in the X1 direction. However, in FIG. 16, illustration of the protection substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 16, the liquid ejection head 1e differs from the liquid ejection head 1b in that instead of the pressure chamber substrate 3, a pressure chamber substrate 3e is provided. The pressure chamber substrate 3e differs from the pressure chamber substrate 3 in that it has a hollow portion KBe1 provided between two adjacent pressure chambers CB1.

The cavity KBe1 opens toward the surface 3F2 but does not open toward the surface 3F1. Therefore, it can also be said that the hollow portion KBe1 is a recess that is recessed in the Z1 direction. In other words, the depth when viewed from the surface 2F1 is described using the cavity KBe1[i]. The deepest part of the cavity KBe1[i] is the pressure chamber CB1[i] and the pressure It is shallower than the chamber CB1[i+1]. Specifically, the Z-axis length zKR from the surface 3F2 to the deepest cavity KBe1[i] is greater than the Z-axis length zCB of the pressure chambers CB1[i] and CB1[i+1]. short.
According to the second modified example, compared to the aspect in which the cavity KB1 opens to the surface 3F1 and does not open to the surface 3F2, the pressure chamber partition CS1[i] and the communication partition RS1[i] are similar to the second embodiment. However, since it is not joined to the pressure chamber partition CS2[i] and the communication partition RS2[i], deformation of the pressure chamber CB1 can be easily absorbed, and structural crosstalk can be suppressed.
Further, according to the second modified example, the liquid ejection head 1e can be manufactured more easily than in the case where the hollow portion KB1 opens to the surface 3F1 and does not open to the surface 3F2. The reason why the manufacturing of the liquid ejection head 1e is facilitated will be described. At the time of manufacture, the pressure chamber substrate 3e and the elastic film of the vibration plate 4 are one silicon single crystal substrate. The manufacturer of the liquid ejection head 1e forms the pressure chamber CB1 and the cavity KB1 in the silicon single crystal substrate by etching the silicon single crystal substrate in the Z1 direction. After the pressure chambers CB1 and the cavity KB1 are formed, the manufacturer thermally oxidizes the silicon single crystal substrate from the Z1 direction to manufacture the pressure chamber substrate 3e and the elastic film of the diaphragm 4. FIG. Thus, in the second modification, the pressure chamber substrate 3e and the elastic film of the vibration plate 4 can be manufactured from one silicon single crystal substrate. On the other hand, in the mode in which the cavity portion KB1 opens to the surface 3F1 and does not open to the surface 3F2, the pressure chamber substrate 3e and the elastic film of the vibration plate 4 are manufactured from separate silicon single crystal substrates. It is difficult to manufacture compared to
According to the second modification, the cavity KB1 opens to the surface 3F1 and does not open to the surface 3F2. The rigidity of the joint portion between the pressure chamber substrate 3e and the vibration plate 4 is increased compared to the case where the pressure chamber substrate 3e and the vibration plate 4 are joined, and cracks are less likely to occur.

In the second modified example, the pressure chamber substrate 3e has the hollow portion KBe1, which is a concave portion, between two adjacent pressure chambers CB1. It may have a certain cavity KB2.

4.3. Third Modification Although the liquid ejection head 1 has the communication substrate 2 in each of the above-described aspects, the communication substrate 2 may be omitted.

FIG. 17 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the third modified example. i is an integer of 2 or more and M−1 or less. FIG. 17 shows a view of the liquid ejection head 1f in the third modification taken along a plane parallel to the YZ plane and passing through the communication flow path RR1, and looking at the cross section in the X1 direction. However, in FIG. 17, illustration of the protection substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 17, the liquid ejection head 1 f differs from the liquid ejection head 1 in that it does not have the communication substrate 2 . In the third modified example, the pressure chamber substrate 3 is laminated on the nozzle substrate 60 . Although not shown in FIG. 17, in the third modification, the nozzle flow path RN that communicates the pressure chambers CB1 and CB2 is provided in the nozzle substrate 60. As shown in FIG.

As illustrated in FIG. 17, in the third modification, the cavity KB1 is defined by the pressure chamber substrate 3 and the surface 6F1 of the nozzle substrate 60. As shown in FIG.
According to the third modification, since the cavity KB1 is provided up to the nozzle substrate 60 in the Z-axis direction, the cavity KB1 is not provided up to the nozzle substrate 60. In other words, the cavity KB1 is located on the surface 3F2. As compared with a mode in which the recess is not open toward the , deformation of the pressure chamber CB1 can be absorbed more easily, and structural crosstalk can be suppressed.

Moreover, the surface 6F1 and the surface 3F2 are joined with an adhesive. This adhesive also flows into the cavity KB1[i]. By flowing the adhesive into the cavity KB1[i], it is possible to suppress the adhesive from flowing into one or both of the pressure chamber CB1 and the nozzle channel RN. Therefore, according to the third modified example, compared with the mode in which the hollow portion KB1 is a concave portion that does not open toward the surface 3F2, the pressure loss of the ink is less likely to change, so the deterioration of the ejection performance is suppressed. can.

4.4. Fourth Modified Example Among the above-described embodiments, in the embodiment in which the cavity KB1 is provided, it is described that the cavity KB2 is provided. However, the hollow portion KB1 may not be provided. Similarly, in the embodiment in which the cavity KR1 is provided among the above-described embodiments, it is described that the cavity KR2 is provided. However, the hollow portion KR1 may not be provided.

4.5. Fifth Modification Although the liquid ejection device 100 in each of the above-described aspects includes the circulation mechanism 94, the circulation mechanism 94 may be omitted.

FIG. 18 is an explanatory diagram showing an example of a liquid ejection device 100g in the fifth modified example. The liquid ejecting apparatus 100 g differs from the liquid ejecting apparatus 100 in that it does not have the circulation mechanism 94 and has a liquid ejecting head 1 g instead of the liquid ejecting head 1 . The liquid ejection head 1g will be described with reference to FIGS. 19 and 20. FIG.

FIG. 19 is an exploded perspective view of the liquid ejection head 1g. 20 is a cross-sectional view taken along line bb in FIG. 19. FIG. A line bb is a virtual line segment parallel to the X axis and passing through the nozzle N. FIG.

As illustrated in FIGS. 19 and 20, the liquid ejection head 1g includes a nozzle substrate 60g, a compliance sheet 61, a communication substrate 2g, a pressure chamber substrate 3g, a vibration plate 4g, a reservoir forming substrate 5g, A wiring board 8 is provided. In other words, the liquid ejection head 1g does not have the compliance sheet 62, has the nozzle substrate 60g instead of the nozzle substrate 60, has the communication substrate 2g instead of the communication substrate 2, and has the pressure chamber substrate 3 instead of the pressure chamber substrate 3. It differs from the liquid ejection head 1 in that it has a pressure chamber substrate 3g, a diaphragm 4g instead of the diaphragm 4, and a storage chamber forming substrate 5g instead of the storage chamber forming substrate 5. FIG.

The communication board 2g differs from the communication board 2 in that the nozzle channel RN, the communication channel RR2, the connection channel RK2, the connection channel RX2, and the discharge channel RA2 are not formed. Since it does not have the nozzle flow path RN, the communication flow path RR1 does not have the bent portion BD1.

Since the communication board 2g does not have the nozzle channel RN, the nozzle board 60g differs from the nozzle board 60 in that it does not block the nozzle channel RN. As can be understood from FIG. 20, when viewed from the Z-axis direction, the nozzles N[m] provided on the nozzle substrate 60g overlap the communication flow paths RR1[m].

The pressure chamber substrate 3g differs from the pressure chamber substrate 3 in that the pressure chambers CB1 and the hollow portions KB2 are not formed.

The diaphragm 4g differs from the diaphragm 4 in that the piezoelectric element PZ2 is not provided.

The storage chamber forming substrate 5g is different from the storage chamber forming substrate 5 in that the opening 50 is not provided and the discharge channel RB2 is not provided.

In the fifth modification, the ink supplied from the liquid container 93 to the inlet 51 flows through the supply channel RB1 and into the supply channel RA1. A part of the ink that has flowed into the supply flow path RA1 flows into the pressure chamber CB1 via the connection flow path RX1 and the connection flow path RK1. Also, part of the ink that has flowed into the pressure chamber CB1 flows into the communication flow path RR1 and is ejected from the nozzle N. As shown in FIG.

In the fifth modification as well, the hollow portion KB1[i] absorbs the deflection of the pressure chamber partition CS1[i] and the pressure chamber partition CS1[i+1] regardless of whether it is in the partially driven state or the fully driven state. Structural crosstalk is suppressed. By suppressing the structural crosstalk, the image quality of the image formed on the medium PP can be improved.

Further, in the fifth modified example, a mode in which the hollow portion KB1 is provided is described, but the hollow portion KR1 may be provided between two adjacent communication flow paths RR1, or the hollow portion KR1 may be provided. The hollow portion KB1 may not be provided.

4.6. Sixth Modification Although the communication flow path RR1 of the liquid ejection head 1g in the fifth modification does not have the bent portion BD1, it may have the bent portion BD1.

FIG. 21 is a diagram showing a cross section of the liquid ejection head 1h in the sixth modification taken along line bb in FIG.

The liquid ejection head 1h differs from the liquid ejection head 1g in that it has a communication substrate 2h instead of the communication substrate 2g and a nozzle substrate 60h instead of the nozzle substrate 60g. The communication substrate 2h differs from the communication substrate 2g in that it has nozzle flow paths RNh. The nozzle channel RNh communicates the communication channel RR1 and the nozzle N with each other. Since the communication substrate 2h has the nozzle flow path RNh, the communication flow path RR1 in the sixth modification has the bent portion BD1. Although not shown in FIG. 21, since the communication flow path RR1 has the bent portion BD1, in the sixth modification, it is preferable to provide the cavity KR1 between two adjacent communication flow paths RR1.

The nozzle substrate 60h differs from the nozzle substrate 60g in that it closes the nozzle flow path RNh. As can be understood from FIG. 21, when viewed from the Z-axis direction, the nozzles N[m] provided on the nozzle substrate 60g do not overlap the communication flow path RR1[m] when m is from 1 to M.

4.7. Seventh Modification Although the liquid ejection head 1g in the fifth modification has the communication substrate 2, it does not have to have the communication substrate 2 as in the third modification.

FIG. 22 is an enlarged view of the vicinity of the pressure chamber CB1[i] in the seventh modification. i is an integer of 2 or more and M−1 or less. In FIG. 22, the liquid ejection head 1k in the seventh modification is cut along a plane parallel to the YZ plane and passing through the nozzles N, and the cut section is viewed in the X1 direction. However, in FIG. 22, illustration of the protective substrate 7 is omitted in order to prevent complication of the drawing.

As illustrated in FIG. 22, the liquid ejection head 1k differs from the liquid ejection head 1g in that it does not have the communication substrate 2. As shown in FIG. The cavity KB1 is defined by the pressure chamber substrate 3 and the surface 6F1 of the nozzle substrate 60. As shown in FIG. In the seventh modified example as well, the hollow portion KB1[i] absorbs the deflection between the pressure chamber partition CS1[i] and the pressure chamber partition CS1[i+1] regardless of whether it is in the partial drive state or the full drive state. The difference in volume is reduced and structural crosstalk is suppressed.

4.8. Eighth Modified Example Among the above-described multiple modes, in the mode having the cavity KB1, the cavity KB1 is provided between two adjacent pressure chambers CB1. Outside, that is, between the Y2 direction end of the pressure chamber substrate 3 and the pressure chamber CB1[1], and between the Y1 direction end of the pressure chamber substrate 3 and the pressure chamber CB1[M], A cavity KB1 may be provided. For example, by providing the cavity portion KB1 in the Y2 direction of the pressure chamber CB1[1], compared to the aspect in which the cavity portion KB1 is not provided in the Y2 direction of the pressure chamber CB1[1], the pressure chamber CB1[1] becomes thinner in the Y2 direction, and the rigidity of the partition of pressure chamber CB1[1] approaches the rigidity of the partition of pressure chamber CB1[2]. The rigidity of the partition wall of the pressure chamber CB1[1] approaches the rigidity of the partition wall of the pressure chamber CB1[2], thereby reducing the difference between the ejection performance of the nozzle N[1] and the ejection performance of the nozzle N[2]. can. Similarly, between the Y2-direction end of the pressure chamber substrate 3 and the pressure chamber CB2[1], and between the Y1-direction end of the pressure chamber substrate 3 and the pressure chamber CB2[M], cavities are formed. A part KB2 may be provided.

Further, among the plurality of aspects described above, in the aspect having the hollow portion KR1, between the Y2-direction end of the communication substrate 2 and the communication flow path RR1[1], and the Y1-direction end of the communication substrate 2 and the communication flow path RR1[M] may also be provided with a cavity KR1. Similarly, between the Y2-direction end of the communication substrate 2 and the communication flow path RR2[1], and between the Y1-direction end of the communication substrate 2 and the communication flow path RR2[M], there are cavities. A portion KR2 may be provided.

4.9. Ninth Modification In each of the aspects described above, the serial-type liquid ejection apparatus 100 in which the transport mechanism 92 on which the liquid ejection head 1 is mounted is reciprocated has been exemplified. The present invention can also be applied to a liquid ejection device.

4.10. Tenth Modification In each of the above-described modes, a heating element may be used instead of the piezoelectric element PZ provided in the pressure chamber CB1 and the pressure chamber CB2 to eject ink.

4.11. Eleventh Modification The above-described liquid ejecting apparatus can be employed in various types of equipment such as facsimile machines and copiers, in addition to equipment dedicated to printing. However, the application of the liquid ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that ejects a colorant solution is used as a manufacturing apparatus for forming a color filter of a liquid crystal display device. Also, a liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes of a wiring board.

1, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1k... Liquid ejection head 2... Communication substrate 2F1, 2F2, CF1, CF2, RF1, RF2... Surface 2b, 2d, 2g, 2h... Communication Substrate 3 Pressure chamber substrate 3F1, 3F2, 4F2, 6F1 Surface 3a, 3e, 3g Pressure chamber substrate 4, 4g Diaphragm 5, 5g Reservoir forming substrate 7 Protection substrate 8 Wiring board 50 Opening 51 Inlet 52 Discharge port 60, 60g, 60h Nozzle substrate 61, 62 Compliance sheet 81 Drive circuit 90 Control device 91 Moving mechanism 92 Conveyance mechanism 93 Liquid container 94 Circulation mechanism 100, 100g Liquid ejection device 810 Wiring 921 Storage case 922 Endless belt BD1, BD2 Bending portion CB, CB1, CB2 Pressure Chambers, CS, CS1, CS2, CW... pressure chamber partition, Com... drive signal, DR, DR0, DR1... droplet, Img... print data, KB1, KB2, KBe1, KR, KR1, KR2, KRd1... cavity, Ln... nozzle row, N... nozzle, PP... medium, PZ1, PZ2... piezoelectric element, RA1... supply channel, RA2... discharge channel, RB1... supply channel, RB2... discharge channel, RJ... circulation channel, RK1, RK2... connection flow path, RN, RNh... nozzle flow path, RR, RR1, RR2... communication flow path, RS, RS1, RS2, RW... communication partition wall, RX1, RX2... connection flow path, SI... control signal, SS... Protective space, ZD... Lower electrode, ZM... Piezoelectric material, ZU... Upper electrode, xCB, xKB, xKR, xRR, xSS... Dimensions.

Claims (17)

a pressure chamber substrate that separates a first pressure chamber and a second pressure chamber containing liquid;
a first driving element provided in a first direction when viewed from the pressure chamber substrate and configured to change the pressure of the first pressure chamber;
a second drive element adjacent to the first drive element, provided in the first direction when viewed from the pressure chamber substrate, and configured to change the pressure of the second pressure chamber;
a nozzle substrate provided in a second direction opposite to the first direction when viewed from the pressure chamber substrate and formed with a plurality of nozzles for ejecting liquid;
with
Between the first pressure chamber and the second pressure chamber, a first hollow portion, which is a space that does not communicate with any of the plurality of nozzles, is provided.
liquid ejection head. Assuming that the arrangement direction of the plurality of nozzles is the nozzle row direction,
In the nozzle row direction, the width of the first cavity is narrower than the width of the first pressure chamber and the width of the second pressure chamber,
The liquid ejection head according to claim 1. The plurality of nozzles includes a first nozzle communicating with the first pressure chamber and a second nozzle communicating with the second pressure chamber,
A communication substrate is provided between the pressure chamber substrate and the nozzle substrate for partitioning a first communication flow path and a second communication flow path,
the first communication channel communicates between the first pressure chamber and the first nozzle;
the second communication channel communicates between the second pressure chamber and the second nozzle;
The first hollow portion is defined by the pressure chamber substrate and a first surface of two surfaces of the communication substrate that is closer to the pressure chamber substrate,
3. The liquid ejection head according to claim 1. The first surface and the second surface of the two surfaces of the pressure chamber substrate, which is closer to the nozzle substrate, are bonded with an adhesive,
The liquid ejection head according to claim 3. A second cavity is provided between the first communication channel and the second communication channel,
The second cavity is a space that does not communicate with any of the plurality of nozzles,
The liquid ejection head according to claim 4. When viewed in the first direction, the first cavity and the second cavity overlap;
The liquid ejection head according to claim 5. The second cavity opens toward the first surface,
With respect to the depth when viewed from the first surface, the deepest part of the second cavity is shallower than the first communication channel and the second communication channel,
7. The liquid ejection head according to claim 5 or 6. When the arrangement direction of the plurality of nozzles is the nozzle row direction,
the width of the second cavity in the nozzle row direction is greater than the width of the first cavity;
The liquid ejection head according to any one of claims 5 to 7. The first hollow portion is defined by the pressure chamber substrate and a third surface of two surfaces of the nozzle substrate that is closer to the pressure chamber substrate,
3. The liquid ejection head according to claim 1. the third surface and the second surface of the two surfaces of the pressure chamber substrate, which is closer to the nozzle substrate, are bonded with an adhesive;
The liquid ejection head according to claim 9. the first pressure chamber, the second pressure chamber, and the first hollow portion open toward a second surface of two surfaces of the pressure chamber substrate, the second surface being closer to the nozzle substrate;
With respect to the depth when viewed from the second surface, the deepest portion of the first hollow portion is shallower than the first pressure chamber and the second pressure chamber,
The liquid ejection head according to any one of claims 1 to 10. a vibration plate provided between the pressure chamber substrate and the first drive element;
The first cavity is defined by the pressure chamber substrate and a surface of the two surfaces of the diaphragm that is closer to the pressure chamber substrate,
The liquid ejection head according to any one of claims 1 to 10. The arrangement direction of the plurality of nozzles is the nozzle row direction,
Assuming that a direction intersecting both the nozzle row direction and the first direction is the flow channel direction,
The dimension of the first hollow portion in the direction of the flow path is equal to or greater than the dimension of the first pressure chamber and the second pressure chamber in the direction of the flow path.
The liquid ejection head according to any one of claims 1 to 12. a first driving element for changing the pressure of the first pressure chamber containing the liquid;
a second driving element for changing the pressure of the second pressure chamber containing the liquid;
a communication substrate formed with a first communication channel communicating with the first pressure chamber and a second communication channel communicating with the second pressure chamber;
a nozzle substrate formed with a plurality of nozzles including a first nozzle communicating with the first communication channel and a second nozzle communicating with the second communication channel;
with
A second cavity is provided between the first communication channel and the second communication channel, and the second cavity is a space that does not communicate with any of the plurality of nozzles.
liquid ejection head. The second cavity opens toward a surface closer to the nozzle substrate, out of two surfaces of the communication substrate.
The liquid ejection head according to claim 14. The first communication channel includes a first bent portion in which the direction of liquid flow changes,
The second communication channel includes a second bent portion in which the direction of liquid flow changes,
The second hollow portion is provided between the first bent portion and the second bent portion,
The liquid ejection head according to claim 15. a liquid ejection head according to any one of claims 1 to 16;
a circulation mechanism for circulating the liquid supplied into the liquid ejection head;
A liquid ejection device comprising:

Images