Piezoelectric actuator and liquid ejecting head

There is provided a piezoelectric actuator including: a substrate that is supported by a support portion; a piezoelectric element that includes a lower electrode formed on the substrate, a piezoelectric layer formed on the lower substrate, and an upper electrode formed on the piezoelectric layer; and a driving circuit that applies a voltage to the piezoelectric element. The upper electrode has a first upper electrode that is positioned on an outer peripheral side of the piezoelectric layer and at least one second upper electrode that is positioned on a center side of the piezoelectric layer, and a voltage applied to the first upper electrode is lower than a voltage applied to the second upper electrode.

This application claims a priority to Japanese Patent Application No. 2009-171891 filed on Jul. 23, 2009 which is hereby expressly incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a piezoelectric actuator and a liquid ejecting head.

2. Related Art

Piezoelectric actuators that are configured by piezoelectric elements are used as liquid ejecting units of piezo-type liquid ejecting heads that are mounted in liquid ejecting apparatuses. The piezoelectric element configuring the piezoelectric actuator is disposed on a substrate that configures a pressure generating chamber. The piezo-type liquid ejecting head transforms the substrate in accordance with a change in the volume of the piezoelectric element and applies pressure to the liquid inside the pressure generating chamber, whereby it ejects the liquid.

There are cases where cracks are generated in the piezoelectric element during driving of the above-described liquid ejecting head. Thus, in JP-A-11-112048, a configuration of a piezoelectric element that suppresses generation of cracks by alleviating the remaining stress generated at the time of manufacturing the piezoelectric element is proposed. In addition, in JP-A-2009-18551, a configuration of a piezoelectric element that suppresses generation of cracks by alleviating the tensile stress generated in the piezoelectric element during a driving process is proposed.

However, there is a problem in that the stress is concentrated in an area of the substrate outside an area in which the piezoelectric element is disposed, and cracks are generated between the end portion of the piezoelectric element and a support portion supporting the substrate.

SUMMARY

An advantage of some aspects of the invention is that it provides a piezoelectric actuator and a liquid ejecting head capable of suppressing generation of cracks. The invention can be implemented in the following forms or applications.

According to an aspect of the invention, there is provided a piezoelectric actuator including: a substrate that is supported by a support portion; a piezoelectric element that includes a lower electrode formed on the substrate, a piezoelectric layer formed on the lower substrate, and an upper electrode formed on the piezoelectric layer; and a driving circuit that applies a voltage to the piezoelectric element. The upper electrode has a first upper electrode that is positioned on an outer peripheral side of the piezoelectric layer and at least one second upper electrode that is positioned on a center side of the piezoelectric layer, and a voltage applied to the first upper electrode is lower than a voltage applied to the second upper electrode.

According to the above-described configuration, the first upper electrode positioned on the outer peripheral side of the piezoelectric layer and at least one second upper electrode positioned on the center side of the piezoelectric layer are included. The voltage applied to the first upper electrode is lower than that applied to the second upper electrode. Thus, in the piezoelectric element, the electric field and the strain applied to the outer peripheral side are weaker than those applied to the center side. Accordingly, in the substrate configuring the pressure generating chamber, concentration of the stress in the area outside the area in which the piezoelectric element is disposed is suppressed. Therefore, generation of cracks between the end portion of the piezoelectric element and the support portion that supports the substrate can be suppressed.

In this case, there is provided the above-described piezoelectric actuator further including: a first resistor that connects the lower electrode and the first upper electrode to each other; and a second resistor that connects the first upper electrode and the second upper electrode to each other.

According to the above-described configuration, the voltage applied to the first upper electrode can be set to be lower than that applied to the second upper electrode.

In this case, there is provided the above-described piezoelectric actuator, wherein, when the voltage applied to the first upper electrode is V1, the voltage applied to the second upper electrode is V2, the first resistor has resistance of R1, and the second resistor has resistance of R2, the voltage V1applied to the first upper electrode is calculated by using the following equation.
V1=V2×R1/(R1+R2)

According to the above-described configuration, the voltage V1applied to the first upper electrode is a voltage acquired by dividing the voltage V2applied to the second upper electrode by the first resistor R1and the second resistor R2. Accordingly, the voltage V1applied to the outer peripheral side of the piezoelectric element can be set to be lower than the voltage V2applied to the center side of the piezoelectric element.

In this case, there is provided the above-described piezoelectric actuator, wherein a voltage applied to one of a plurality of the second upper electrodes decreases as the corresponding second upper electrode is disposed further toward an outer peripheral side.

According to the above-described configuration, a difference in voltages applied to two second upper electrodes that are adjacent to each other can be decreased. Accordingly, the amount of change in the strain generated from the center portion of the piezoelectric element toward the outer peripheral side thereof can be decreased. Therefore, concentration of the stress can be suppressed in the piezoelectric element.

In this case, there is provided the above-described piezoelectric actuator, further including a vibration plate that is formed in a lower side of the lower electrode and is transformed by the piezoelectric element.

According to the above-described configuration, concentration of the stress in the area outside an area in which the piezoelectric element is brought into contact with the vibration plate is suppressed. Accordingly, the strain applied to the outer peripheral side is lower than that applied to the center side in the piezoelectric element. Therefore, concentration of the stress in the area outside the area in which the piezoelectric element is disposed is suppressed in the vibration plate configuring the pressure generating chamber, whereby generation of cracks between the end portion of the piezoelectric element and the support portion supporting the vibration plate can be suppressed.

In this case, there is provided a liquid ejecting head including: any one of the above-described piezoelectric actuators; a pressure generating chamber that is formed in the substrate; and a nozzle plate that is formed in a lower side of the substrate and has a nozzle communicating with the pressure generating chamber.

According to the above-described configuration, generation of cracks between the end portion of the piezoelectric element and the support portion supporting the vibration plate can be suppressed.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Embodiment

FIG. 1is an exploded perspective view schematically showing the schematic configuration of an ink jet recording head as an example of a liquid ejecting head according to a first embodiment of the invention.FIG. 2Ais a plan view ofFIG. 1, viewed from the upper side inFIG. 1, with a protection substrate30, which has a driving circuit200, removed from the ink jet recording head shown inFIG. 1.FIG. 2Bis a cross-sectional view ofFIG. 2Ataken along line IIB-IIB.

As shown inFIG. 1, a flow path forming substrate10according to this embodiment is formed from a silicon monocrystal substrate with a crystal plane orientation of the (110) plane. On one face of the flow path forming substrate10, an elastic film50is formed which is formed in advance from silicon dioxide by thermal oxidation.

In the flow path forming substrate10, pressure generating chambers12that are partitioned using a plurality of partition walls11are arranged in the width direction D2(short side direction) of the pressure generating chamber12by performing anisotropic etching from the other surface side. In addition, on one end portion side of the flow path forming substrate10in the longitudinal direction D1of the pressure generating chamber12, ink supply paths13and communication paths14are partitioned by the partition walls11.

At one end of the communication paths14, a communication portion15is formed that configures a part of a reservoir100that becomes a common ink chamber (liquid chamber) of the respective pressure generating chambers12. In other words, in the flow path forming substrate10, liquid flow paths are disposed that are formed of the pressure generating chambers12, the ink supply paths13, the communication paths14, and the communication portion15.

The ink supply path13communicates with one end portion side of the pressure generating chamber12in the longitudinal direction and has a cross-sectional area that is smaller than that of the pressure generating chamber12. For example, according to this embodiment, the ink supply path13is formed to have a width smaller than that of the pressure generating chamber12by narrowing the flow path on the pressure generating chamber12side between the reservoir100and the respective pressure generating chamber12in the width direction. Accordingly, the flow path resistance of ink flowing into the pressure generating chamber12from the communication flow path14is maintained to be constant. In addition, as described above, according to this embodiment, the ink supply path13is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides thereof.

Alternatively, the ink supply path may be formed not by narrowing the width of the flow path but by narrowing the flow path in the thickness direction. In addition, each communication path14communicates with the side of the ink supply path13that is located opposite to the pressure generating chamber12and has a cross-sectional area that is larger than that of the ink supply path13in the width direction D2(short side direction). In this embodiment, the communication path14is formed so as to have a cross-sectional area that is the same as that of the pressure generating chamber12.

In other words, in the flow path forming substrate10, the pressure generating chambers12, the ink supply paths13, that have a cross-sectional area smaller than that of the pressure generating chamber12in the short side direction, and the communication paths14, that communicate with the ink supply paths13and each has a cross-sectional area larger than that of the ink supply path13in the width direction D2, are arranged so as to be partitioned by the plurality of partition walls11.

In addition, on the opening face side of the flow path forming substrate10, a nozzle plate20, in which nozzle openings21are formed that each communicates with an area near the end portion of one of the pressure generating chambers12on the side opposite to the ink supply path13, is fixed with an adhesive agent, a thermal welding film or the like. The nozzle plate20is formed, for example, of a glass ceramic, a silicon monocrystal substrate, stainless steel or the like.

On the other hand, on the side of the flow path forming substrate10that is located opposite to the opening face, the elastic film50made from silicon dioxide is formed as described above. An insulating film55, which is formed in a laminated manner from zirconium oxide (ZrO2) or the like, is formed on the elastic film50.

In addition, on the insulating film55, a lower electrode film60, for example, formed from platinum (Pt), iridium (Ir), or the like, a piezoelectric layer70formed from lead zirconium titanate (PZT) as an example of a piezoelectric material or the like, upper electrode films81and82as first upper electrodes that are, for example, formed from platinum (Pt), iridium (Ir), or the like, and an upper electrode film80as a second upper electrode are formed in a laminated manner, whereby they configure a piezoelectric element300. Here, the piezoelectric element300is the portion that includes the lower electrode film60, the piezoelectric layer70, and the upper electrode films80,81, and82.

Generally, any one side of the upper electrode films80,81, and82and the lower electrode film60is configured as a common electrode, and the other side of the electrode films and the piezoelectric layer70are configured by being patterned for each pressure generating chamber12. In this embodiment, as shown inFIGS. 1 and 2A, by disposing the lower electrode film60so as to extend in an area facing the plurality of pressure generating chambers12, the lower electrode film60is configured as the common electrode of the plurality of piezoelectric elements300. In addition, by separating the upper electrode films80,81, and82and the piezoelectric layer70for each piezoelectric element300, the upper electrode films80,81, and82are configured as individual electrodes of the respective piezoelectric elements300.

In addition, lead electrodes90,91, and92that are drawn out from near the end portion located on the ink supply path13side and extend to the insulating film55, and, for example, are formed from gold (Au) or the like are each connected to the respective upper electrode films80,81, and82that are individual electrodes of the piezoelectric elements300.

On the flow path forming substrate10on which the above-described piezoelectric elements300are formed, that is, on the lower electrode film60, the elastic film50, and the lead electrodes90,91, and92, a protection substrate30, which has a reservoir portion31that constitutes at least a part of the reservoir100, is bonded through an adhesive agent35. This reservoir portion31, in this embodiment, is formed so as to perforate the protection substrate30in the thickness direction and extend in the width direction D2of the pressure generating chamber12and communicates with the communication portion15of the flow path forming substrate10, as described above, so as to configure the reservoir100to become a common ink chamber for the pressure generating chambers12.

Alternatively, the communication portion15of the flow path forming substrate10may be divided into a plurality of portions for the pressure generating chambers12, so that only the reservoir portion31is configured as a reservoir. Furthermore, for example, it may be configured that only the pressure generating chamber12is disposed on the flow path forming substrate10, and the ink supply path13that allows the reservoir and the pressure generating chambers12to communicate each other is disposed in a member (for example, the elastic film50, the insulating film55, or the like) interposed between the flow path forming substrate10and the protection substrate30.

In addition, in an area of the protection substrate30that faces the piezoelectric elements300, a piezoelectric element holding portion32is formed with a space that does not block the movement of the piezoelectric elements300. As long as the piezoelectric element holding portion32has a space that does not block the movement of the piezoelectric elements300, the space may be or may not be sealed.

It is preferable that a material, such as glass, a ceramic material or the like that has a same rate of thermal expansion as that of the flow path forming substrate10, is used for the above-described protection substrate30. In this embodiment, the protection substrate30is formed by using a silicon monocrystal substrate that is formed from the same material as that of the flow path forming substrate10.

In addition, a through hole33that passes through the protection substrate30in the thickness direction is formed in the protection substrate30. In addition, a portion of each lead electrode90near the end portion thereof that is extracted from each piezoelectric element300is disposed so as to be exposed to the inside of the through hole33.

In addition, a driving circuit200, which is used for driving the piezoelectric elements300arranged so as to be parallel to one another, is fixed on the protection substrate30. As the driving circuit200, for example, a circuit substrate, a semiconductor integrated circuit (IC), or the like may be used. In addition, the driving circuit200and the lead electrodes90,91, and92are electrically connected to each other through a connection wire121that is formed of a conductive wire such as a bonding wire.

In addition, a compliance substrate40that is formed of a sealing film41and a fixing plate42is bonded on the protection substrate30. Here, the sealing film41is formed of a flexible material with low rigidity (for example, a poly phenylene sulfide (PPS) film with a thickness of 6 μm), and one-side face of the reservoir portion31is sealed by the sealing film41. The fixing plate42is formed of a hard material (for example, stainless steel (SUS) or the like with a thickness of 30 μm) such as a metal. An area of the fixing plate42that faces the reservoir100is an opening portion43that is completely removed in the thickness direction. Accordingly, one-side face of the reservoir100is sealed only by the sealing film41which is flexible.

According to the ink jet recording head of this embodiment, the inside is filled with ink from the reservoir100up to the nozzle opening21by inserting ink from an ink introducing opening that is connected to an external ink supplying unit that is not shown in the figure, and then, a voltage is applied between the lower electrode film60and the upper electrode films80,81, and82corresponding to each pressure generating chamber12in accordance with a recording signal transmitted from the driving circuit200, whereby the elastic film50, the insulating film55, the lower electrode film60, and the piezoelectric layer70are transformed so as to be bent. Accordingly, the pressure inside each pressure generating chamber12is increased, whereby ink droplets are ejected from the nozzle opening21.

The piezoelectric actuator is configured to include the piezoelectric element300that has the upper electrode films80,81, and82and the lead electrodes90,91, and92, the insulating film55and the elastic film50as substrates in which the piezoelectric element300is disposed, and a driving circuit200that drives the piezoelectric element300.

Here, the piezoelectric element300, the driving circuit200, and a vibration plate that is displaced in accordance with driving of the piezoelectric element300are collectively referred to as a piezoelectric actuator. In the above-described example, the elastic film50, the insulating film55, and the lower electrode film60act as the vibration plate. However, only the lower electrode film60may remain without disposing the elastic film50and the insulating film55so as to configure the lower electrode film60as the vibration plate.

FIG. 3is an external perspective view of one piezoelectric element300including the upper electrode films80,81, and82and the lead electrodes90,91, and92. The lower electrode film60may be included as a common electrode of the piezoelectric element300.

The upper electrode films80,81, and82that are individual electrodes of the piezoelectric element300are arranged in the piezoelectric layer70in the width direction D2with the longitudinal direction thereof being as D1. The upper electrode films81and82as the first upper electrodes are arranged on the outer peripheral side of the piezoelectric element300in the width direction D2. The upper electrode film80as the second upper electrode is arranged in the center portion of the piezoelectric element300in the width direction D2. In other words, the upper electrode film80is arranged in a position interposed between the upper electrode films81and82. The lead electrodes90,91, and92are connected to the upper electrode films80,81, and82.

FIG. 4is a circuit diagram, which includes a first resistor R1and a second resistor R2, for representing voltages applied to the first upper electrode and the second upper electrode. The first resistor R1is connected to the upper electrode films81and82as the first upper electrodes through connection wires126aand126c. In addition, the first resistor R1is connected to the lower electrode film60through a connection wire126d. The second resistor R2is connected to the upper electrode films81and82as the first upper electrodes through connection wires126aand126c. In addition, the second resistor R2is connected to the upper electrode film80as the second upper electrode through a connection wire126b.

When the voltage of the lower electrode film60is used as a reference voltage, a voltage applied to the upper electrode films81and82as the first upper electrodes is denoted by V1, and a voltage applied to the upper electrode film80as the second upper electrode is denoted by V2, the voltage V1is calculated by using the following Equation (1).
V1=V2×R1/(R1+R2)  (1)

As represented by Equation (1), the voltage V1is acquired by dividing the voltage V2at a center position P of the first resistor R1and the second resistor R2that are aligned in series. Accordingly, the voltage V1applied to the upper electrode films81and82as the first upper electrodes can be set to be lower than the voltage V2applied to the upper electrode film80as the second upper electrode.

FIG. 5is a partial cross-sectional view showing the elastic film50and the insulating film55as the substrates supported by the partition walls11as a support portion of the flow path forming substrate10.FIG. 5is a cross-sectional view viewed in the longitudinal direction D1shown inFIG. 1. As described above, in the piezoelectric layer70, the voltage V1applied to the upper electrode films81and82disposed on the outer peripheral side in the width direction D2is lower than the voltage V2applied to the upper electrode film80disposed on the center side in the width direction D2.

Accordingly, in the piezoelectric layer70, the electric field and the strain on the outer peripheral side in the width direction D2is lower than those on the center side in the width direction D2. Accordingly, concentration of the stress in areas Q1and Q2of the insulating film55and the elastic film50as substrates in which the piezoelectric element300is not disposed, that is, between the end portion of the piezoelectric element300and the partition wall11as the support portion in the width direction D2is suppressed. Therefore, generation of cracks can be suppressed.

The first resistor R1and the second resistor R2may be arranged inside the driving circuit200shown inFIG. 1. Alternatively, the first and second resistors R1and R2may be connected to the connection wire121shown inFIG. 2Bor the lead electrodes90,91, and92shown inFIG. 3.

In this embodiment, the first resistor R1and the second resistor R2are arranged. However, a resistor included in the upper electrode film by changing the width of the upper electrode film so as to change the conductive cross-section area of the upper electrode film may be used.

As described above, the piezoelectric actuator described in this embodiment includes: the insulating film55and the elastic film50as substrates supported by the partition walls11as support portions; the piezoelectric element300that includes the lower electrode film60as the lower electrode formed on the substrate, the piezoelectric layer70formed on the lower electrode film60, and the upper electrode films80,81, and82as the upper electrodes formed on the piezoelectric layer70; and the driving circuit200that applies a voltage to the piezoelectric element300. In addition, the upper electrode films80,81, and82include the upper electrode films81and82as the first upper electrodes positioned on the outer peripheral side of the piezoelectric layer70and the upper electrode film80as the second upper electrode positioned on the center side of the piezoelectric layer70, and the voltage applied to the upper electrode films81and82is lower than that applied to the upper electrode film80.

According to such a configuration, in the piezoelectric element300, the electric field and the strain that are applied to the outer peripheral side are lower than those applied to the center side. Accordingly, in the insulating film55and the elastic film50as substrates configuring the pressure generating chamber12, concentration of the stress in the areas Q1and Q2(seeFIG. 5) that are positioned on the outer sides of the area in which the piezoelectric element300is arranged and are between the end portion of the piezoelectric element300and the partition wall11as the support portion supporting the substrate is suppressed. Therefore, generation of cracks in the areas Q1and Q2can be suppressed.

Second Embodiment

In a second embodiment of the invention, a piezoelectric actuator in which a first upper electrode surrounding a second upper electrode disposed on the center side will be described.

FIG. 6Ais a diagram representing that an upper electrode film84as the first upper electrode is disposed so as to surround an upper electrode film83as the second upper electrode. The upper electrode film83is disposed on the center portion of the piezoelectric layer70. The upper electrode film84is disposed so as to surround the upper electrode film83.

To the upper electrode films83and84, lead electrodes93and94are connected. In order not to allow the upper electrode films83and84to intersect with each other, the upper electrode film84is not formed in the area Q3.

FIG. 6Bis a diagram showing that the upper electrode84as the first upper electrode is disposed so as to surround the upper electrode film83as the second upper electrode and the upper electrode films83and84intersect with each other also in the area Q3. In the area Q3of the piezoelectric layer70of the piezoelectric element300bshown inFIG. 6B, an insulating layer130is formed between the upper electrode films83and84, whereby the upper electrode films83and84are not in the conductive state.

As described above, the upper electrode film84is disposed so as to surround the upper electrode film83. Accordingly, a voltage applied to the upper electrode film84as the first upper electrode disposed on the outer peripheral side in the longitudinal direction D1and the width direction D2is lower than a voltage applied to the upper electrode film83as the second upper electrode disposed on the center side. Therefore, in the piezoelectric element300ashown inFIG. 6Aand the piezoelectric element300bshown inFIG. 6B, the strain applied to the outer peripheral side in the longitudinal direction D1and the width direction D2is lower than that applied to the center side.

Accordingly, in the insulating film55and the elastic film50as substrates configuring the pressure generating chamber12, concentration of the stress in the areas Q1and Q2(seeFIG. 5) that are positioned on the outer sides of the area in which the piezoelectric elements300aand300bare arranged and are between the end portion of the piezoelectric elements300aand300band the partition wall11as the support portion supporting the substrate is suppressed. Therefore, generation of cracks in the areas Q1and Q2can be suppressed.

The other configurations of the piezoelectric actuator according to the second embodiment are the same as those described in the first embodiment.

Third Embodiment

In a third embodiment of the invention, a piezoelectric actuator in which a plurality of second upper electrodes is included in a piezoelectric layer70will be described.

FIG. 7Ais a diagram showing that upper electrode films85and89as first upper electrodes having their longitudinal direction as D1are arranged on the outer peripheral sides of the piezoelectric layer70in the width direction D2. In addition, upper electrode films86,87, and88as second upper electrodes having their longitudinal direction as D1and are disposed on the center portion of the piezoelectric layer70in the width direction D2.

To the upper electrode films85to89, lead electrodes95to99used for applying voltages to respective upper electrode films are respectively connected.

The voltage applied to the upper electrode film87that is disposed on the center line in the width direction D2has a maximum voltage of all the voltages of the upper electrode films85to89. Accordingly, the voltage applied to the upper electrode films86and88adjacent to the outer peripheral side of the upper electrode film87disposed on the center line in the width direction D2is lower than that applied to the upper electrode film87. In other words, the voltage applied to one of the upper electrode films86to88as the second upper electrodes decreases as the corresponding second upper electrode is disposed further toward the outer peripheral side in the with direction D2.

In addition, a voltage applied to the upper electrode film85that is adjacent to the outer peripheral side of the upper electrode film86in the width direction D2is lower than that applied to the upper electrode film86. Similarly, a voltage applied to the upper electrode film89that is adjacent to the outer peripheral side of the upper electrode film88in the width direction D2is lower than that applied to the upper electrode film88.

Under this configuration, a difference in voltages applied to two second upper electrodes that are adjacent to each other in the width direction D2can be decreased. Accordingly, in the piezoelectric layer70of the piezoelectric element300c, the amount of change in the strain generated from the center portion toward the outer peripheral side can be decreased. Therefore, concentration of stress in the piezoelectric layer70of the piezoelectric element300ccan be suppressed.

FIG. 7Bis a diagram showing a piezoelectric actuator in which a first upper electrode is disposed so as to surround a plurality of second upper electrodes. An upper electrode film111as the second upper electrode is disposed so as to surround an upper electrode film110as the second upper electrode disposed on the center portion of the piezoelectric layer70. In addition, an upper electrode film112as the first upper electrode is disposed so as to surround the upper electrode film111as the second upper electrode. To the upper electrode films110,111, and112, lead electrodes120,121, and122are respectively connected.

Accordingly, differences in voltages applied to two second upper electrodes that are adjacent to each other in the width direction D2and the longitudinal direction D1can be decreased. Accordingly, in the piezoelectric layer70of the piezoelectric element300d, the amount of change in the strain generated from the center portion toward the outer peripheral side can be decreased. Therefore, concentration of stress in the piezoelectric layer70of the piezoelectric element300dcan be suppressed.

An ink jet recording head that includes the piezoelectric actuator as described in the first to third embodiments configures a part of a recording head unit that includes an ink flow path that communicates with an ink cartridge or the like and is built in an ink jet recording apparatus.FIG. 8is a schematic diagram showing an example of the ink jet recording apparatus.

As shown inFIG. 8, to recording head units1A and1B that have ink jet recording heads, cartridges2A and2B that configure an ink supplying unit are detachably attached. A carriage3in which the recording head units1A and1B are mounted is disposed in a carriage shaft5that is installed to a device main body4so as to be movable in the shaft direction. For example, the recording head units1A and1B are configured so as to eject a black ink composition, and a color ink composition.

Then, as the driving force of a driving motor6is transferred to the carriage3through a plurality of gears, not shown in the figure, and a timing belt7, the carriage3in which the recording head units1A and1B are mounted moves along the carriage shaft5. On the other hand, a platen8is disposed in the device main body4along the carriage3. The platen8is configured to rotate depending on the driving force of a feed motor not shown in the figure. Accordingly, a recording sheets S that is a recording medium such as a paper sheet fed by a feed roller or the like can be transported so as to be wound around the platen8.

In addition, in the first to third embodiments, the ink jet recording head has been described as an example of a liquid ejecting head. However, the invention is targeted for a general liquid ejecting head in a broad meaning. Thus, it is apparent that the invention can be applied to a liquid ejecting head that ejects liquid other than ink. As other liquid ejecting heads, for example, there are various recording heads used in an image recording apparatus such as a printer, a color material ejecting head that is used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head that is used for forming an electrode of an organic EL display, an FED (field emission display), or the like, and a bio organic material ejecting head that is used for manufacturing a bio chip, and the like.