Liquid ejecting head and liquid ejecting apparatus

Provided is a liquid ejecting head including a pressure chamber forming substrate for forming a pressure chamber which is filled with liquid, a nozzle through which the ink is ejected in a direction along the pressure chamber forming substrate, and a communication flow path which allows the pressure chamber to communicate with the nozzle. The nozzle and the communication flow path are formed in the pressure chamber forming substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2014-006678 filed on Jan. 17, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to technology relating to ejection of liquid, such as ink.

2. Related Art

There are various types of technology relating to ejection of liquid, such as ink, onto a printing medium, such as a paper sheet for printing. A liquid ejecting head in which a pressure chamber forming substrate for forming a pressure chamber, a nozzle plate for forming a nozzle, and a communication substrate for forming a nozzle communication path through which the pressure chamber communicates with the nozzle are stacked on each other has been disclosed in, for example, JP-A-2013-154485.

In the configuration disclosed in JP-A-2013-154485, the pressure chamber forming substrate, the communication substrate, and the nozzle plate, all of which have a plate shape, are disposed in a state where the posture thereof is perpendicular to an ink ejection direction. Accordingly, when viewed from a printing medium side, the area (which is the area of a liquid ejection surface of the liquid ejecting head) of the head is great. Thus, it is difficult to arrange a plurality of nozzles with high density. Furthermore, in the case of a configuration in which a plurality of liquid ejecting heads are arranged, a plurality of nozzles are distributed over a wide range. Accordingly, it is difficult to maintain a uniform gap between the liquid ejection surface and a printing medium, over a plurality of heads.

In the configuration disclosed in JP-A-2013-154485, the pressure chamber, the nozzle communication path, and the nozzle are formed in separate substrates. Accordingly, when the liquid ejecting head is manufactured, it is difficult to form, with high accuracy, a flow path from the pressure chamber to the nozzle. Particularly, an error is likely to occur in the flow path, at a bonded portion between the substrates. As a result, ejection properties (such as an ejection amount, an ejecting direction, and the like) of liquid ejected from the nozzles are likely to deviate from designed values, and thus a variation in the ejection properties occurs. Furthermore, a configuration in which the pressure chamber forming substrate, the communication substrate, and the nozzle plate are constituted of silicon single crystal substrates is disclosed in JP-A-2013-154485. However, when materials of the three substrates differ from each other, the degree of thermal expansion is different for each substrate. Accordingly, the error in the flow path, which occurs at the bonded portion between the substrates, varies due to a temperature (heat). As a result, the variation in ejection properties becomes more significant.

SUMMARY

An advantage of some aspects of the invention is to reduce the area of a liquid ejecting head, viewed from a liquid ejecting direction, and suppress the variation in ejection properties with a simple configuration.

According to an aspect of the invention, there is provided a liquid ejecting head including a pressure chamber forming substrate for forming a pressure chamber which is filled with liquid, a nozzle through which the liquid is ejected in a direction along the pressure chamber forming substrate, and a communication flow path which allows the pressure chamber to communicate with the nozzle, in which the nozzle and the communication flow path are formed in the pressure chamber forming substrate.

In this case, liquid is ejected in the direction along the pressure chamber forming substrate. Thus, the area of the liquid ejecting head, viewed from the ink ejection direction, can be reduced, compared to the configuration disclosed in JP-A-2013-154485, in which a pressure chamber forming substrate, a communication substrate, and a nozzle plate are disposed in a state where the posture thereof is perpendicular to the ink ejection direction. As a result, a plurality of nozzles can be provided with high density and, further, it is easy to maintain a uniform gap between a liquid ejection surface and a printing medium. Furthermore, since the pressure chamber, the communication flow path, and the nozzle are formed in the same substrate (which is the pressure chamber forming substrate), the flow paths from the pressure chambers to the nozzles can be formed with high accuracy. Accordingly, it is possible to eliminate the possibility that an error may occur, in a flow path, at a bonded portion between the substrates and the extent of the error may vary due to temperature. As a result, it is possible to suppress the variation in ejection properties of liquid ejected from the nozzles. Furthermore, the pressure chamber, the communication flow path, and the nozzle can be formed by a common process (for example, etching of a plate material). As a result, it is possible to simplify the manufacturing process of the liquid ejecting head. In addition, since it is not necessary to provide a nozzle plate, the number of parts is reduced. Thus, the configuration of the liquid ejecting head can be simplified. Furthermore, it is not necessary to flatten the surfaces to which a nozzle plate is bonded. As a result, it is possible to reduce the accuracy necessary for manufacturing or assembling of the liquid ejecting head. Therefore, according to the invention, the area of the liquid ejecting head, viewed from the liquid ejection direction, can be reduced and the variation in ejection properties can be suppressed with a simple configuration.

In the liquid ejecting head, it is preferable that the liquid ejecting head further include a liquid storage chamber which is formed in the pressure chamber forming substrate and in which liquid to be supplied to the pressure chamber is stored.

In this case, the liquid storage chamber, in addition to the pressure chamber, the communication flow path, and the nozzle, is formed in the pressure chamber forming substrate. As a result, the configuration of the liquid ejecting head can be simplified, compared to the configuration in which the liquid storage chamber is formed in a substrate separate from the pressure chamber forming substrate.

In the liquid ejecting head, it is preferable that the liquid ejecting head further include a compliance sheet having flexibility which is disposed on one surface of the pressure chamber forming substrate and constitutes a wall surface of the liquid storage chamber.

In this case, the wall surface of the liquid storage chamber is constituted by the compliance sheet which has flexibility and is disposed on one surface of the pressure chamber forming substrate. Accordingly, pressure change in the liquid storage chamber can be suppressed (absorbed) by the compliance sheet. Furthermore, it is possible to more stably supply, to the pressure chamber, the liquid stored in the liquid storage chamber, compared to the configuration in which the compliance sheet is not provided. As a result, it is possible to further suppress the variation in ejection properties.

In the liquid ejecting head, it is preferable that the liquid ejecting head further include a communication plate which is disposed on one surface of the pressure chamber forming substrate and forms a liquid storage chamber in which liquid to be supplied to the pressure chamber is stored.

In this case, the liquid storage chamber is formed in a substrate (which is the communication plate) separate from the pressure chamber forming substrate. As a result, the liquid storage chamber having adequate capacity can be obtained regardless of the thickness of the pressure chamber forming substrate (for example, even when the thickness of the pressure chamber forming substrate is thin).

In the liquid ejecting head, it is preferable that the liquid ejecting head further include a compliance sheet having flexibility which is disposed on a surface of the communication plate, which is the surface opposite to a surface facing the pressure chamber forming substrate, and constitutes a wall surface of the liquid storage chamber.

In this case, the wall surface of the liquid storage chamber is constituted by the compliance sheet which has flexibility and is disposed on one surface of the communication plate. Accordingly, pressure change in the liquid storage chamber can be absorbed by the compliance sheet. Furthermore, it is possible to more stably supply, to the pressure chamber, the liquid stored in the liquid storage chamber, compared to the configuration in which the compliance sheet is not provided. As a result, it is possible to further suppress the variation in ejection properties.

According to another aspect of the invention, there is provided a liquid ejecting apparatus which includes the liquid ejecting head according to the aspect described above. The liquid ejecting apparatus is, for example, a printer in which ink is ejected onto a printing medium, such as a paper sheet for printing. However, a use of the liquid ejecting apparatus of the invention is not limited to printing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1is a partial configuration view of a printing apparatus100of an ink jet type according to Embodiment 1. The printing apparatus100is a liquid ejecting apparatus in which ink as an example of liquid is ejected onto a printing medium200, such as a paper sheet for printing. The printing apparatus100includes a controller12, a transporting mechanism14, and a head module16. The controller12collectively controls components of the printing apparatus100. The transporting mechanism14transports the printing medium200in a predetermined direction A1, in accordance with the control by the controller12.

An ink cartridge300filled with ink is mounted on the printing apparatus100. The head module16ejects, onto the printing medium200, ink supplied from the ink cartridge300, in accordance with the control by the controller12. The head module16is a line head in which a plurality of liquid ejecting heads20are arranged to be in two rows, along a direction A2intersecting (generally, perpendicular to) the transporting direction A1of the printing medium200, as illustrated inFIG. 1. The liquid ejecting heads20are arranged in a so-called staggered manner. In the illustration ofFIG. 1, the positions of respective liquid ejecting heads20of both the three liquid ejecting heads20constituting the upper-side row inFIG. 1and the two liquid ejecting heads20constituting the lower-side row inFIG. 1are different in the direction A2. A plurality of head modules16can be arranged in parallel, along the transporting direction A1of the printing medium200. The head module16includes a plurality of liquid ejecting heads20. The respective liquid ejecting heads20have a common configuration.

FIG. 2illustrates a perspective view of the liquid ejecting head20and a partially enlarged view thereof. The liquid ejecting head20is a head chip in which ink is ejected onto the printing medium200through a plurality of nozzles N arranged to be in two rows (which are a nozzle row GA and a nozzle row GB). An IC chip22having a driving circuit embedded therein is mounted on the liquid ejecting head20. The driving circuit generates driving signals. In the following description, a direction in which ink is ejected from the respective nozzles N of the liquid ejecting head20is referred to as a Z direction and a direction (which is the longitudinal direction of the liquid ejecting head20) in which the nozzle row GA or the nozzle row GB extends is referred to as an X direction. In addition, a direction perpendicular to both the Z direction and the X direction is referred to as a Y direction.

In the printing apparatus100, each liquid ejecting head20is disposed in a state where the Z direction thereof is directed downward (in other words, directed to the printing medium200side) in the vertical direction. Accordingly, the XY plane perpendicular to the Z direction is a horizontal plane substantially parallel to the printing medium200. The nozzles N of the plurality of the liquid ejecting heads20are distributed over the range greater than the width (which is the width of the printing medium200in the direction A2) of the printing medium200, as illustrated inFIG. 1. Accordingly, ink is ejected onto the printing medium200through the nozzles N of the respective liquid ejecting heads20of the head module16while the printing medium200is transported by the transporting mechanism14, and in such a manner an image can be printed onto the printing medium200.

In the liquid ejecting head20, pressure chamber forming substrates52, diaphragms54, and protection plates58are stacked on both surfaces (hereinafter, referred to as mounting surfaces)420of a base substrate42located in the central portion of the liquid ejecting head20, as illustrated in the enlarged view ofFIG. 2. In the protection plate58, the IC chip22is provided on a surface opposite to a surface facing the diaphragm54. The components on one mounting surface420of the base substrate42correspond to the nozzle row GA and the components on the other mounting surface420thereof correspond to the nozzle row GB. The respective nozzles N constituting the nozzle row GA and the respective nozzles N constituting the nozzle row GB are disposed facing each other, with the base substrate42interposed therebetween. In the X direction, the positions of the respective nozzles N of the nozzle row GA are different from the positions of the respective nozzles N of the nozzle row GB, as illustrated inFIG. 2. However, the components on both mounting surfaces420of the base substrate42are substantially symmetrically arranged with the base substrate42interposed therebetween. Furthermore, the specific configurations of the components are the same. Accordingly, in the following description, the focus is placed on the components corresponding to the nozzle row GA and the descriptions of the components corresponding to the nozzle row GB will not be repeated.

FIG. 3illustrates plan views of the base substrate42, the pressure chamber forming substrate52, the diaphragm54, and the protection plate58, when viewed from the −Y direction.FIG. 4is a cross-sectional view of the liquid ejecting head20, taken along line IV-IV inFIG. 2. The base substrate42is a member having a plate shape extending in the X direction, as illustrated inFIG. 3. Any material or manufacturing method can be applied to the base substrate42. A silicon (Si) single crystal substrate or a stainless steel substrate, for example, can be used as the base substrate42. The base substrate42is a plate material functioning as a base for stacking members, such as the pressure chamber forming substrate52, the diaphragm54, and the protection plate58. Furthermore, the base substrate42functions as a spacer for defining the Y-directional gap between the nozzle row GA and the nozzle row GB.

The pressure chamber forming substrate52is mounted on the mounting surface420of the base substrate42, as illustrated inFIG. 4. The pressure chamber forming substrate52is fixed to the base substrate42, using, for example, an adhesive. The pressure chamber forming substrate52is constituted of a base portion71, a space forming portion72, and side wall portions73, as illustrated inFIG. 3. The base portion71is a portion on the Z-directional side (which is the ink ejecting side) of the pressure chamber forming substrate52. In the base portion71, ink flow paths (which are the nozzles N, first flow paths522, opening portions524, and second flow paths526) corresponding to the respective nozzles N constituting the nozzle row GA are arranged, in the X direction, spaced apart from each other (generally, at equal intervals). The space forming portion72is located on the −Z-directional side (which is a side opposite to the ink ejection side) of the pressure chamber forming substrate52. The space forming portion72is an opening portion of which three sides are surrounded by the base portion71and the side wall portions73on both sides of the pressure chamber forming substrate52. The side wall portions73are portions on both sides of the space forming portion72and continuously extend from the base portion71.

Each of the plurality ink flow paths formed in the base portion71is constituted of the nozzle N, the first flow path522, the opening portion524, and the second flow path526, as illustrated inFIG. 3. The first flow path522linearly extends in the Z direction and allows the nozzle N to communicate with the opening portion524. The opening portion524functions as a pressure chamber66for applying pressure to ink. The second flow path526linearly extends in the Z direction and allows the opening portion524to communicate with the space forming portion72. The respective components (which are the nozzle N, the first flow path522, the opening portion524, and the second flow path526) described above pass through the base portion71in the Y direction. Any material or manufacturing method can be applied to the pressure chamber forming substrate52. A silicon single crystal substrate is selectively removed by, for example, semiconductor manufacturing technology, such as photolithography and etching, in such a manner that the pressure chamber forming substrate52is formed.

The silicon single crystal substrate (having a plate shape) fixed, using an adhesive, to the mounting surface420of the base substrate42or the surface of the diaphragm54, which is the surface facing the base substrate42, is subjected to, for example, anisotropic dry etching, in such a manner that the pressure chamber forming substrate52having a shape illustrated inFIG. 3can be easily formed with high accuracy. In this case, the cross section of the nozzle N in the XY plane has a rectangular shape (generally, a square shape) and does not have a circular shape. However, according to the results of extensive studies by the inventor, it is possible to know that, even when the cross section of the nozzle N has a rectangular shape, adequate ink ejection properties can be ensured.

The respective components (which are the nozzle N, the first flow path522, the opening portion524, the second flow path526, and the space forming portion72) formed in the pressure chamber forming substrate52may not pass through the pressure chamber forming substrate52in the Y direction. Furthermore, the respective components described above may be formed by isotropic dry etching or isotropic wet etching. Alternatively, two silicon single crystal substrates may be bonded to form the pressure chamber forming substrate52and the components described above may be formed by performing isotropic dry etching or isotropic wet etching on the bonded surface of each silicon single crystal substrate. In this case, the cross section of the nozzle N can have a circular shape or a shape similar to a circular shape.

The diaphragm54is mounted on the surface of the pressure chamber forming substrate52, which is the surface opposite to the surface facing the base substrate42, as illustrated inFIG. 4. The diaphragm54is fixed, using, for example, an adhesive, to the pressure chamber forming substrate52. The diaphragm54is a plate-shaped member capable of oscillating elastically. The diaphragm54has a configuration in which, for example, an elastic film formed of an elastic material, such as oxide silicon, and an insulation film formed of an insulating material, such as zirconium oxide, are stacked on each other. In the surface of the diaphragm54, which is the surface opposite to the surface facing the pressure chamber forming substrate52, a piezoelectric element56is disposed at the position corresponding to the plurality of opening portions524in the pressure chamber forming substrate52, as illustrated inFIGS. 3 and 4. The piezoelectric element56is a laminated body in which a piezoelectric body is interposed between facing electrodes. One electrode constituting the piezoelectric element56is, for example, a common electrode extending over the plurality of opening portions524and the other electrodes are a plurality of separate electrodes. The other electrode is separately formed for each opening portion524. The piezoelectric body continuously extends over the plurality of opening portions524. Furthermore, the piezoelectric body may be separately formed for each opening portion524. The piezoelectric element56may be separately provided for each opening portion524.

The space forming portion72interposed between the base substrate42and the diaphragm54functions as a liquid storage chamber (which is a reservoir)62which is a common liquid storage chamber of the plurality of nozzles N, as can be understood fromFIGS. 3 and 4. The ink supplied from the ink cartridge300is stored in the liquid storage chamber62. Both the diaphragm54and the piezoelectric element56are disposed on the opening portions524interposed between the base substrate42and the diaphragm54, and thus the respective opening portions524function as the pressure chamber (which is a cavity)66for applying pressure to ink.

The respective second flow paths526(which are tubular spaces extending in the Z direction) interposed between the base substrate42and the diaphragm54allow the liquid storage chamber62to communicate with the pressure chambers66. Thus, the second flow paths526function as the supply flow paths64through which the ink stored in the liquid storage chamber62is supplied to the respective pressure chambers66. Accordingly, in the plurality of supply flow paths64, the ink stored in the liquid storage chamber62is divided into plural streams, and then is supplied, in parallel, to the respective pressure chambers66. As a result, the respective pressure chambers66are filled with ink. Furthermore, the respective first flow paths522(which are tubular spaces extending in the Z direction) interposed between the base substrate42and the diaphragm54function as communication flow paths68which allow the pressure chambers66to communicate with the nozzles N. As described above, the pressure chamber forming substrate52is a substrate in which the liquid storage chamber62, the supply flow path64, the pressure chamber66, the communication flow path68, and the nozzles N are formed. The ink flow path in the liquid ejecting head20is constituted of, in order, the liquid storage chamber62, the supply flow path64, the pressure chamber66, the communication flow path68, and the nozzle N, as can be understood from the above description.

A plurality of connection terminals57are formed on the surface of the diaphragm54, which is the surface opposite to the surface facing the pressure chamber forming substrate52, as illustrated inFIG. 4. The plurality of connection terminals57are electrically connected to both the common electrode and the separate electrodes of the piezoelectric element56. The respective connection terminals57are arranged, in the X direction, spaced apart from each other (generally, at equal intervals). The respective connection terminals57are conductor patterns which linearly extend from the piezoelectric element56to the −Z-directional side.

The protection plate58is mounted on the surface of the diaphragm54, which is the surface opposite to the surface facing the pressure chamber forming substrate52, as illustrated inFIG. 4. The protection plate58is fixed, using, for example, an adhesive, to the surface of the diaphragm54, in which the plurality of connection terminals57are formed. A concave portion586is formed in the surface of the protection plate58, which is the surface facing the diaphragm54. The piezoelectric element56is accommodated in the concave portion586. The IC chip22having the driving circuit embedded therein is mounted on the surface of the protection plate58, which is the surface opposite to the surface facing the diaphragm54, as illustrated inFIGS. 3 and 4. Furthermore, an opening portion582which has a rectangular shape and has inclined surfaces584A and584B is formed on the −Z-directional side of the protection plate58. In the surface of the protection plate58, a plurality of signal wirings59extend from the IC chip22to the lower end portion of the inclined surface584A, as illustrated inFIG. 4. Each signal wiring59is electrically connected to the connection terminal57corresponding to the signal wiring59.

Accordingly, driving signals are supplied, through both the signal wiring59and the connection terminal57, from the IC chip22(which is the driving circuit) to the respective electrodes of the piezoelectric element56. The piezoelectric element56separately oscillates in accordance with the driving signals, for each area corresponding to the opening portion524. Furthermore, the diaphragm54oscillates in accordance with the oscillation of the piezoelectric element56, and thus the pressure (in other words, the volume of the pressure chamber66) of the ink in the pressure chamber66varies. As a result, ink is ejected from the nozzles N, due to an increase in the pressure in the pressure chamber66. As can be understood from the above description, the piezoelectric element56functions as a pressure generating element which causes the pressure in the pressure chamber66to vary, and in such a manner the ink in the pressure chamber66is ejected from the nozzles N. The diaphragm54is fixed, using, for example, an adhesive, to the protection plate58, in which the diaphragm54is in close contact with the protection plate58. Furthermore, the opening portion582of the protection plate58is sufficiently away from the piezoelectric element56. Accordingly, only a part of the diaphragm54, which is a portion corresponding to the concave portion586of the protection plate58, oscillates in accordance with the driving signals.

According to Embodiment 1, ink is ejected in the Z direction along the pressure chamber forming substrate52, as described above. Thus, the area of the liquid ejecting head20, viewed from the ink ejection direction (which is the Z direction), can be reduced, compared to the configuration disclosed in JP-A-2013-154485, in which a pressure chamber forming substrate, a communication substrate, and a nozzle plate are disposed in a state where the posture thereof is perpendicular to the ink ejection direction. As a result, a plurality of nozzles N can be provided with high density and, further, it is easy to maintain a uniform gap between a liquid ejection surface and the printing medium200, over the plurality of liquid ejecting heads20.

According to Embodiment 1, since the pressure chamber66, the communication flow path68, and the nozzles N are formed in the same substrate (which is the pressure chamber forming substrate52), the ink flow paths from the pressure chambers66to the nozzles N can be formed with high accuracy. Accordingly, it is possible to eliminate the possibility that an error may occur, in a flow path, at a bonded portion between the substrates and the extent of the error may vary due to temperature. As a result, it is possible to suppress the variation in ejection properties of ink ejected from the nozzles N. Furthermore, the pressure chamber66, the communication flow path68, and the nozzles N can be formed in the pressure chamber forming substrate52, by a common process (for example, anisotropic dry etching). As a result, it is possible to simplify the manufacturing process of the liquid ejecting head20.

According to Embodiment 1, it is not necessary to provide a nozzle plate. When the nozzle plate is provided, the nozzle plate is fixed in a close-contact state. Thus, in the surfaces (which are the Z-directional lateral surfaces of the base substrate42, the pressure chamber forming substrate52, the diaphragm54, and the protection plate58) to which the nozzle plate is fixed, it is necessary to sufficiently reduce a difference in level. In other words, manufacturing or assembling the liquid ejecting head20requires high accuracy. In contrast, according to this embodiment, since it is not necessary to provide a nozzle plate, the number of parts is reduced. Thus, the configuration of the liquid ejecting head20can be simplified. Furthermore, it is not necessary to flatten the surfaces to which a nozzle plate is bonded. As a result, it is possible to reduce the accuracy necessary for manufacturing or assembling of the liquid ejecting head20.

Therefore, according to Embodiment 1, the area of the liquid ejecting head20, viewed from the ink ejection direction, can be reduced and the variation in ejection properties can be suppressed with a simple configuration. Furthermore, according to Embodiment 1, the liquid storage chamber62and the supply flow path64are also formed in the pressure chamber forming substrate52. As a result, the configuration of the liquid ejecting head20can be simplified, compared to the configuration in which the liquid storage chamber62and the supply flow path64are formed in a substrate separate from the pressure chamber forming substrate52.

Next, Embodiment 2 will be described. In the following descriptions of Embodiments 2 to 4, the same reference numerals and letters are given to components of which the configurations are the same as those in Embodiment 1. Furthermore, the descriptions thereof will not be repeated.

FIG. 5is a cross-sectional view of the liquid ejecting head20according to Embodiment 2.FIG. 5corresponds toFIG. 4which is referred to in Embodiment 1.FIG. 6illustrates plan views of a compliance plate44and a compliance sheet46. As can be understood fromFIGS. 5 and 6, the configuration of the liquid ejecting head20according to Embodiment 2 and the configuration of the liquid ejecting head20described in Embodiment 1 have a difference in that both the compliance plate44and the compliance sheet46are further provided in the liquid ejecting head20of Embodiment 2.

The compliance plate44is provided on the mounting surface420of the base substrate42, as illustrated inFIG. 5. The compliance plate44is fixed, using, for example, an adhesive, to the base substrate42. The compliance plate44has a rectangular shape extending in the X direction, as illustrated inFIG. 6. In the −Z-directional side of the compliance plate44, an opening portion442is provided in a state where the opening portion442passes through, in the Y direction, the compliance plate44. The size or the position of the opening portion442substantially corresponds to the space forming portion72(which is the liquid storage chamber62) of the pressure chamber forming substrate52. Any material can be used as the compliance plate44. For example, a metallic material, such as stainless steel, can be used as a material of the compliance plate44.

The compliance sheet46is provided over the surface of the compliance plate44, which is the surface opposite to the surface facing the base substrate42, as illustrated inFIGS. 5 and 6. The compliance sheet46is a sheet having flexibility and is constituted of, for example, synthetic resin or a metallic material. The compliance sheet46is fixed, in a close-contact manner, to the compliance plate44, using, for example, an adhesive, except for a part of the compliance sheet46, which is the portion corresponding to the opening portion442of the compliance plate44. Accordingly, when a pressure is applied to the compliance sheet46, only a part of the compliance sheet46, which is the portion corresponding to the opening portion442, is bent.

The pressure chamber forming substrate52is fixed, using, for example, an adhesive, to the surface of the compliance sheet46, which is the surface opposite to the surface facing the base substrate42, as illustrated inFIG. 5. As described in Embodiment 1, the pressure chamber forming substrate52is the substrate in which the liquid storage chamber62, the supply flow path64, the pressure chamber66, the communication flow path68, and the nozzles N are formed. Accordingly, the ink flow path from the liquid storage chamber62to the nozzle N has the same configuration as that in Embodiment 1. In the liquid storage chamber62, a wall surface on the base substrate42side is constituted of the compliance sheet46having flexibility, as illustrated inFIG. 5. Most of a part of the compliance sheet46, which is the portion constituting the wall surface of the liquid storage chamber62, faces the opening portion442and is not fixed to the compliance plate44. Accordingly, pressure change in the liquid storage chamber62can be absorbed by the compliance sheet46.

In the case of Embodiment 2 described above, similarly to Embodiment 1, the area of the liquid ejecting head20, viewed from the ink ejection direction (which is the Z direction), can be reduced and the variation in ejection properties can be suppressed with a simple configuration. Furthermore, according to Embodiment 2, the wall surface of the liquid storage chamber62is constituted of the compliance sheet46which has flexibility and is provided on the surface of the pressure chamber forming substrate52, which is the surface facing the base substrate42. Accordingly, pressure change in the liquid storage chamber62can be absorbed by the compliance sheet46. Furthermore, it is possible to more stably supply, to the pressure chamber66, the ink stored in the liquid storage chamber62, compared to the configuration in which the compliance sheet46is not provided. As a result, it is possible to further suppress the variation in ejection properties.

FIG. 7is a cross-sectional view of the liquid ejecting head20according to Embodiment 3.FIG. 8illustrates plan views of a communication plate48and a pressure chamber forming substrate53, seen from the −Y direction. Upon comparison with the liquid ejecting head20described in Embodiment 1, the communication plate48is further provided in the liquid ejecting head20of Embodiment 3, as can be understood fromFIGS. 7 and 8. The liquid ejecting head20of Embodiment 3 and the liquid ejecting head20of Embodiment 1 have a difference in that both a liquid storage chamber63(which is a space forming portion482) and a supply flow path65(which is a through-hole484) are formed not in a pressure chamber forming substrate53but in the communication plate48.

The communication plate48is provided on the mounting surface420of the base substrate42, as illustrated inFIG. 7. The communication plate48is fixed, using, for example, an adhesive, to the base substrate42. The communication plate48has a rectangular shape extending in the X direction, as illustrated inFIG. 8. The space forming portion (which is a concave portion)482functioning as the liquid storage chamber63is formed on the −Z-directional side of the surface of the communication plate48, which is the surface facing the base substrate42. Furthermore, in the communication plate48(specifically, in the Z-directional end portion of the space forming portion482), a plurality of through-holes484which pass through the communication plate48in the Y direction are arranged, in the X direction, spaced apart from each other (generally, at equal intervals), as illustrated inFIG. 8.

The pressure chamber forming substrate53is fixed, using, for example, an adhesive, to the surface of the communication plate48, which is the surface opposite to the surface facing the base substrate42, as illustrated inFIG. 7. In the base portion71on the Z-directional side of the pressure chamber forming substrate53, parts (which are the nozzles N, the first flow paths522, and the opening portions524) of the ink flow paths corresponding to the respective nozzles N constituting the nozzle row GA are arranged, in the X direction, spaced apart from each other (generally, at equal intervals), as illustrated inFIG. 8.

The space forming portion482interposed between the base substrate42and the communication plate48functions as the liquid storage chamber63which is a common liquid storage chamber of the plurality of nozzles N, as can be understood fromFIGS. 7 and 8. Each through-hole484allows the liquid storage chamber63to communicate with the pressure chamber66. The through-hole484functions as the supply flow path65through which the ink stored in the liquid storage chamber63is supplied to the pressure chamber66. The configuration of the ink flow path from the pressure chamber66to the nozzle N is the same as that of Embodiment 1. As can be understood fromFIGS. 3 and 8, the pressure chamber forming substrate52of Embodiment 1 is the substrate in which the liquid storage chamber62, the supply flow path64, the pressure chamber66, the communication flow path68, and the nozzles N are formed and the pressure chamber forming substrate53of Embodiment 3 is the substrate in which the pressure chamber66, the communication flow path68, and the nozzles N are formed. In Embodiment 3, the liquid storage chamber63(which is the space forming portion482) and the supply flow path65(which is the through-hole484) are formed not in the pressure chamber forming substrate53but in the communication plate48.

In the liquid ejecting head20of Embodiment 3, the space forming portion482of the communication plate48functions as the liquid storage chamber63, as described above. Accordingly, upon comparison with the case of Embodiment 1 or Embodiment 2, the liquid storage chamber63having adequate capacity can be obtained regardless of the thickness of the pressure chamber forming substrate53. When, for example, the capacity of the liquid storage chamber63is small, the flow-path resistance increases. Thus, when the piezoelectric element56is driven at a high frequency, there is a possibility that inadequate ink supply may occur. However, according to this embodiment, it is possible to eliminate inadequate ink supply at the time of high-frequency driving of the piezoelectric element56. As a result, high-speed printing can be performed.

As described above, the liquid ejecting head20of Embodiment 3 includes the communication plate48which is disposed on the surface of the pressure chamber forming substrate53, which is the surface facing the base substrate42, and forms the liquid storage chamber63in which ink to be supplied to the pressure chamber66is stored. Even in this embodiment, similarly to Embodiment 1, the area of the liquid ejecting head20, viewed from the ink ejection direction (which is the Z direction), can be reduced and the variation in ejection properties can be suppressed with a simple configuration. Furthermore, according to Embodiment 3, the liquid storage chamber63is formed in the communication plate48which is a substrate separate from the pressure chamber forming substrate53. Thus, the liquid storage chamber63having adequate capacity can be obtained regardless of the thickness of the pressure chamber forming substrate53(for example, even when the thickness of the pressure chamber forming substrate53is thin). Accordingly, it is possible to eliminate inadequate ink supply at the time of high-frequency driving of the piezoelectric element56. As a result, high-speed printing can be performed.

FIG. 9is a cross-sectional view of the liquid ejecting head20according to Embodiment 4. The liquid ejecting head20of Embodiment 4 has a configuration in which the configurations of Embodiments 2 and 3 are used in combination, as can be understood fromFIG. 9. The configuration of the liquid ejecting head20of Embodiment 4 and the configuration of the liquid ejecting head20described in Embodiment 1 has a difference in that the liquid ejecting head20of Embodiment 4 includes the compliance plate44and the compliance sheet46which are described in Embodiment 2 and the communication plate48and the pressure chamber forming substrate53which are described in Embodiment 3.

The compliance plate44, the compliance sheet46, the communication plate48, and the pressure chamber forming substrate53, in addition to the diaphragm54and the protection plate58, are stacked on the base substrate42, as illustrated inFIG. 9. The compliance plate44and the compliance sheet46are similar to those described in Embodiment 2 and the configurations thereof are as illustrated inFIG. 6, except that the Z-directional width of the opening portion442of the compliance plate44is slightly greater than that of Embodiment 2. The size or the position of the opening portion442substantially corresponds to the space forming portion482(which is the liquid storage chamber63) of the communication plate48. Furthermore, the communication plate48and the pressure chamber forming substrate53are similar to those described in Embodiment 3 and the configurations thereof are as illustrated inFIG. 8.

Even in the case of Embodiment 4, similarly to Embodiment 1, the area of the liquid ejecting head20, viewed from the ink ejecting direction (which is the Z direction), can be reduced and the variation in ejection properties can be suppressed with a simple configuration. Furthermore, according to Embodiment 4, the wall surface of the liquid storage chamber63is constituted by the compliance sheet46which has flexibility and is disposed on the surface of the communication plate48, which is the surface facing the base substrate42. In addition, most of a part of the compliance sheet46, which is the portion constituting the wall surface of the liquid storage chamber63, faces the opening portion442and is not fixed to the compliance plate44. Accordingly, a pressure change in the liquid storage chamber63can be absorbed by the compliance sheet46. Furthermore, according to Embodiment 4, since the liquid storage chamber63is formed in the communication plate48which is a substrate separate from the pressure chamber forming substrate53, the liquid storage chamber63having adequate capacity can be obtained regardless of the thickness of the pressure chamber forming substrate53. Accordingly, it is possible to eliminate inadequate ink supply at the time of high-frequency driving of the piezoelectric element56. As a result, high-speed printing can be performed.

MODIFICATION EXAMPLES

The embodiments described above can be modified in various ways. Examples of the specific aspects of modification are described below. Two aspects or more selected from the examples described below can be appropriately combined as long as they do not contradict each other.

(1) In the embodiments described above, the nozzle row GA is formed in one mounting surface420of the base substrate42and the nozzle row GB is formed in the other mounting surface420. However, the components in either one of the mounting surfaces420may be removed. In other words, a nozzle row can be formed in only one mounting surface420of the base substrate42. However, when nozzle rows are formed in both mounting surfaces420of the base substrate42, a plurality of nozzles N can be provided with high density. The number of nozzles N is not limited to the plural number and may be one or more. When the number of nozzles N is one, the number of communication flow paths68, the pressure chambers66, the supply flow paths64, the supply flow paths65, or the like is one.

(2) The head module16(which is a line head) in which a plurality of liquid ejecting heads20are arranged in the direction A2perpendicular to the transporting direction A1of the printing medium200is exemplified in the embodiments described above. However, the invention can be applied to a serial head. For example, a head module18illustrated inFIG. 10is a serial head in which a plurality of liquid ejecting heads20according to the embodiments described above are mounted on a carriage. The head module18reciprocates in the direction A2and ejects ink through the respective nozzles N, while the printing medium200is transported (in the direction A1).

(3) In the embodiments described above, the IC chip22may not be provided on the protection plate58. A driving circuit for generating driving signals may be provided in the controller12and the driving signals from the driving circuit may be supplied to the connection terminal57through a flexible wiring substrate. In this case, it is not necessary to form the signal wiring59on the surface of the protection plate58. Furthermore, the IC chip22may be provided on the flexible wiring substrate, in a Chip-On-Film (COF) manner. When a case in which a driving circuit is provided in the controller12and a case in which the IC chip22is provided on a flexible wiring substrate are compared to each other, the latter can achieve the condition that the driving circuit is located closer to the liquid ejecting head20. Accordingly, it is possible to obtain an effect, such as improved noise-resistance properties and a reduction in distortion of driving-signal wave form. Furthermore, in the case where the driving circuit is provided in the controller12or the case where the IC chip22is provided on a flexible wiring substrate, the driving signals from the driving circuit may be supplied not to the connection terminal57formed on the surface of the diaphragm54but to the signal wiring59formed on the surface of the protection plate58. In this case, the driving signals are supplied to the piezoelectric element56, through both the signal wiring59and the connection terminal57. The diaphragm54having the connection terminal57formed therein faces the pressure chamber forming substrate53and constitutes the wall surface of the ink flow path. Accordingly, in a case where the driving signals are supplied to the connection terminal57, when a wiring substrate is pressed to the connection terminal57, at the time of connecting the flexible wiring substrate and the connection terminal57, there is a possibility that distortion may occur in the ink flow path, due to a pressing force. In contrast, when the driving signals are supplied to the signal wiring59, a flexible wiring substrate is connected to the signal wiring59on the protection plate58. Thus, even when the flexible wiring substrate is pressed to the signal wiring59, at the time of connecting the flexible wiring substrate and the signal wiring59, distortion does not occur in the ink flow path.

(4) In Embodiment 2 or Embodiment 4, the compliance sheet46may be disposed in only the portion corresponding to the liquid storage chamber62or63.

(5) A component (which is a pressure generating element) for changing the pressure in the pressure chamber66is not limited to the piezoelectric element56. For example, an oscillating body, such as an electrostatic actuator, can be used as a pressure generating element. Furthermore, a pressure generating element is not limited to a component which applies mechanical oscillation to the pressure chamber66. For example, a heater element (which is a heater) which generates, in a heating manner, air bubbles in the pressure chamber66, in such a manner that the pressure in the pressure chamber66changes, can be used as a pressure generating element. Any element can be used as a pressure generating element, as long as it changes the pressure in the pressure chamber66. The pressure changing method (for example, a piezoelectric method or a thermal method) or the specific configuration of a pressure generating element is not limited.

(6) The liquid ejecting apparatus of the invention can also be applied to an apparatus, such as a facsimile machine and a copying machine, other than a printer. In addition, a use of the liquid ejecting apparatus according to the invention is not limited to printing. For example, a liquid ejecting apparatus for ejecting a solution of coloring material can be used as a manufacturing apparatus for forming a color filter for a liquid crystal display. Furthermore, a liquid ejecting apparatus for ejecting a solution of conductive material can be used as a manufacturing apparatus for forming wiring or an electrode of a wiring substrate.