JP2015116784A - Liquid ejection head and liquid ejection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection head suppressing occurrence of variations of discharge characteristics of liquid, achieving reduction of a head controller in size and being capable of printing at a high speed, and further to provide a liquid ejection device.SOLUTION: A liquid ejection head includes: a plurality of piezoelectric actuators causing a change in pressure to be generated in each of pressure generating chambers; and switch elements 236 controlling whether or not a drive potential driving the plurality of piezoelectric actuators is applied to the piezoelectric actuators. First piezoelectric actuators 300A out of the plurality of piezoelectric actuators eject liquid from nozzle openings corresponding to the pressure generating chambers on the basis of the drive potential applied by control of a switch element 236A, and a plurality of second piezoelectric actuators 300B out of the plurality of piezoelectric actuators is applied with the drive potential by control of a switch element 236B while the liquid is being ejected from the first piezoelectric actuators 300A. The plurality of second piezoelectric actuators 300B is supplied with the drive potential from the common switch element 236B.

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject liquid from nozzle openings, and more particularly to an ink jet recording head and an ink jet recording apparatus that eject ink as liquid.

  As an ink jet recording head which is a liquid ejecting head, for example, a flow path forming substrate in which a plurality of pressure generating chambers communicating with nozzle openings are arranged in parallel, and a vibration plate is provided on one surface side of the flow path forming substrate. The piezoelectric actuator is provided, and by changing the volume in the pressure generation chamber by the piezoelectric actuator, a pressure change is generated and an ink droplet is ejected from a nozzle opening communicating with the pressure generation chamber.

  Among the pressure generation chambers arranged in parallel in such an ink jet recording head, the pressure generation chambers provided at the end portions in the parallel arrangement direction are adjacent to each other with one side in the parallel arrangement direction sandwiching the partition wall. In contrast, the pressure generation chambers are not adjacent to each other in the side-by-side direction. For this reason, the rigidity of the partition on the side where the pressure generation chamber is not adjacent is higher than the partition on the side where the pressure generation chamber is adjacent, and it is difficult to deform due to the pressure change of the pressure generation chamber. The difference between the pressure loss due to the deformation of the partition of the pressure generation chamber at the end and the pressure loss of the pressure generation chamber in the center in the side-by-side direction, that is, the pressure generation chamber in which the pressure generation chambers exist on both sides in the side-by-side direction This causes a problem that the ejection characteristics such as the flying speed of the ink droplets ejected from the nozzle openings vary.

  For this reason, a dummy pressure generation chamber that is not used for ink droplet ejection is provided next to the pressure generation chamber provided at the end in the juxtaposed direction used for ink droplet ejection, and pressure generation for ink droplet ejection is provided. A configuration is disclosed in which variations in the ink droplet ejection characteristics are suppressed by suppressing variations in the rigidity of the partition walls on both sides of the chamber (see, for example, Patent Document 1).

JP 2004-262242 A

  However, the provision of the dummy pressure generation chamber can make the rigidity of the partition walls on both sides of the pressure generation chamber used for ejection uniform. However, the provision of the dummy pressure generation chamber merely varies the ejection characteristics of the ink droplets. There is a problem that it is sometimes difficult to suppress this. This is because, during printing in which ink droplets are ejected, the piezoelectric actuator used for ejection is applied with a driving potential, but the piezoelectric actuator is not provided corresponding to the dummy pressure generating chamber, or dummy pressure generation is performed. Even if a piezoelectric actuator corresponding to the chamber is provided, the piezoelectric actuator corresponding to the dummy pressure generating chamber is not driven, so the rigidity of the partition between the dummy pressure generating chamber and the pressure generating chamber used for discharge This is because there may be a difference in the rigidity of the partition between the pressure generation chambers used.

  When a drive potential is applied to the piezoelectric actuator corresponding to the dummy pressure generation chamber, if all the piezoelectric actuators including the piezoelectric actuator corresponding to the dummy pressure generation chamber are provided with a switch element, an output signal line from the switch element There is a problem that the number of heads increases and the head controller becomes larger. In particular, when a plurality of dummy pressure generating chambers are provided, the number of piezoelectric actuators that are driven wastefully increases, and the head controller further increases in size.

Further, when a driving potential is applied to the piezoelectric actuator corresponding to the dummy pressure generating chamber, it is necessary to generate pixel data for the piezoelectric actuator corresponding to the dummy pressure generating chamber, which affects high-speed printing. There is a problem.
Such a problem exists not only in an ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a liquid ejecting head and a liquid ejecting apparatus capable of suppressing variations in liquid ejection characteristics, miniaturizing a head controller, and capable of high-speed printing. Objective.

An aspect of the present invention that solves the above problems includes a piezoelectric actuator that causes a pressure change in a pressure generation chamber, and a switch element that controls whether or not a driving potential for driving the piezoelectric actuator is applied to the piezoelectric actuator. And a first piezoelectric actuator among the plurality of piezoelectric actuators ejects liquid from a nozzle opening corresponding to the pressure generating chamber based on a driving potential applied by control of the switch element, and the plurality of actuators The second piezoelectric actuator is applied with a driving potential under the control of the switch element while the liquid is ejected from the first piezoelectric actuator, and there are a plurality of the second piezoelectric actuators, and the plurality of the second piezoelectric actuators The drive potential is supplied from the common switch element. A liquid-jet head according to claim.
In such an aspect, by applying a driving potential to the plurality of second piezoelectric actuators with a common switch element, the number of switch elements can be reduced, so that the head controller having the switch elements can be reduced in size and heat generation can be reduced. it can. In addition, since the number of switch elements can be reduced to reduce pixel data and the like, high-speed printing is possible. Further, the pressure generating chamber provided with the first piezoelectric actuator is used as a pressure generating chamber used for discharging liquid, and the pressure generating chamber provided with the second piezoelectric actuator is used as a dummy pressure generating chamber not used for discharging liquid. By arranging the dummy pressure generation chamber outside the end portion where the pressure generation chambers for parallel use are arranged and driving the second piezoelectric actuator, the pressure fluctuation chamber can be changed regardless of the position of the discharge pressure generation chamber. Variation in pressure loss due to propagation can be suppressed, and variation in ejection characteristics such as liquid flight speed can be suppressed.

  Here, the switch element applies a drive signal in which the drive potential is changed to the first piezoelectric actuator, and ejects liquid from the nozzle opening communicating with the pressure generating chamber corresponding to the first piezoelectric actuator. Preferably, the common switch element does not eject the liquid from the nozzle opening communicating with the pressure generation chamber corresponding to the second piezoelectric actuator without applying the drive signal to the second piezoelectric actuator. . According to this, it is not necessary to flow a change amount of the drive potential used for ejection, that is, a drive signal having a large waveform, to the switch elements common to the plurality of second piezoelectric actuators. It is possible to suppress an excessive current from flowing between the two.

Another aspect of the present invention includes a piezoelectric actuator that causes a pressure change in the pressure generation chamber, and a switch element that controls whether or not a driving potential for driving the piezoelectric actuator is applied to the piezoelectric actuator. The first piezoelectric actuator among the plurality of piezoelectric actuators ejects liquid from a nozzle opening corresponding to the pressure generation chamber based on a driving potential applied by the control of the switch element, and the plurality of the piezoelectric actuators The second piezoelectric actuator is a liquid ejecting head in which a driving potential is applied without the control of the switch element while the liquid is ejected from the first piezoelectric actuator.
In this aspect, since the driving potential can be applied to the plurality of second piezoelectric actuators without passing through the switch elements, the number of switch elements is further reduced, and the head controller having the switch elements is reduced in size and heat generation is reduced. Can be achieved. Further, the pressure generating chamber provided with the first piezoelectric actuator is used as a pressure generating chamber used for discharging liquid, and the pressure generating chamber provided with the second piezoelectric actuator is used as a dummy pressure generating chamber not used for discharging liquid. By arranging the dummy pressure generation chamber outside the end portion where the pressure generation chambers for parallel use are arranged and driving the second piezoelectric actuator, the pressure fluctuation chamber can be changed regardless of the position of the discharge pressure generation chamber. Variation in pressure loss due to propagation can be suppressed, and variation in ejection characteristics such as liquid flight speed can be suppressed.

  Here, it is preferable that the drive potential applied to the second piezoelectric actuator without being controlled by the switch element is a reference potential. According to this, by setting the drive potential applied to the second piezoelectric actuator as the reference potential, it is not necessary to generate a drive potential applied to the second piezoelectric actuator, and the circuit configuration can be simplified. .

  Further, it is preferable that the pressure generating chamber corresponding to the second piezoelectric actuator is not filled with liquid. According to this, when a driving potential is applied to the second piezoelectric actuator, the pressure fluctuation corresponding to the second piezoelectric actuator is suppressed by suppressing the pressure fluctuation in the liquid in the pressure generating chamber corresponding to the second piezoelectric actuator. It is possible to suppress the pressure fluctuation of the liquid in the chamber from affecting other pressure generation chambers. Further, the liquid in the pressure generation chamber corresponding to the second piezoelectric actuator thickens and solidifies, and the rigidity of the partition wall between the pressure generation chamber corresponding to the second piezoelectric actuator and the pressure generation chamber of the first piezoelectric actuator, that is, It is possible to suppress the change in the bending characteristics.

  Moreover, it is preferable that the pressure generation chamber corresponding to the second piezoelectric actuator is not provided with the nozzle opening corresponding to the pressure generation chamber. According to this, it is possible to suppress problems caused by ink or the like adhering to the nozzle opening communicating with the pressure generating chamber corresponding to the second piezoelectric actuator.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect.
According to this aspect, it is possible to realize a liquid ejecting apparatus that can suppress variations in the liquid ejection characteristics, reduce the size of the head controller, and can perform high-speed printing.

1 is a diagram illustrating a schematic configuration of a recording apparatus according to a first embodiment of the invention. FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. FIG. 3 is a plan view of a main part of the recording head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of a main part of the recording head according to the first embodiment of the invention. FIG. 3 is a schematic diagram illustrating a wiring configuration of the recording head according to the first embodiment of the invention. FIG. 3 is a block diagram illustrating a control configuration of the recording apparatus according to the first embodiment of the invention. It is a block diagram which shows the control structure of the drive circuit which concerns on Embodiment 1 of this invention. It is a wave form diagram which shows the various signals which concern on Embodiment 1 of this invention. It is a block diagram which shows the example of a change of the drive circuit which concerns on Embodiment 1 of this invention.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an ink jet recording apparatus which is an example of a liquid ejecting apparatus according to Embodiment 1 of the invention.
As shown in the drawing, in an ink jet recording apparatus I, an ink jet recording head unit II (hereinafter also referred to as a head unit II) having a plurality of ink jet recording heads 1 is detachable from a cartridge 2 constituting ink supply means. The carriage 3 on which the head unit II is mounted is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. For example, the head unit II ejects a black ink composition and a color ink composition, respectively.

  Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the head unit II is mounted is moved along the carriage shaft 5. On the other hand, the apparatus main body 4 is provided with a conveyance roller 8 as a conveyance means, and a recording sheet S which is a recording medium such as paper is conveyed by the conveyance roller 8. Note that the conveyance means for conveying the recording sheet S is not limited to the conveyance roller, and may be a belt, a drum, or the like.

  An example of an ink jet recording head 1 mounted on such an ink jet recording apparatus I will be described with reference to FIGS. 2 is an exploded perspective view of an ink jet recording head that is an example of a liquid ejecting head according to Embodiment 1 of the present invention, FIG. 3 is a cross-sectional view of the ink jet recording head, and FIG. 5 is a plan view showing the arrangement of piezoelectric actuators, FIG. 5 is a cross-sectional view taken along line AA ′ of FIG. 4, and FIG. 6 is a diagram showing a connection configuration between the piezoelectric actuators and a drive circuit.

  As shown in the figure, the ink jet recording head 1 of the present embodiment includes a plurality of members such as a head main body 11 and a case member 40, and the plurality of members are joined by an adhesive or the like. In the present embodiment, the head body 11 includes a flow path forming substrate 10 that is an actuator substrate of the present embodiment, a communication plate 15, a nozzle plate 20, a protective substrate 30, and a compliance substrate 45.

  The flow path forming substrate 10 constituting the head body 11 is provided with a plurality of nozzle openings 21 through which pressure generation chambers 12 partitioned by a plurality of partition walls discharge ink by performing anisotropic etching from one side. It is arranged along the direction. Hereinafter, this direction is referred to as a direction in which the pressure generating chambers 12 are arranged side by side or a first direction X. Further, the flow path forming substrate 10 is provided with a plurality of rows in which the pressure generation chambers 12 are arranged in parallel in the first direction X, and in this embodiment, two rows. An arrangement direction in which a plurality of rows of the pressure generation chambers 12 in which the pressure generation chambers 12 are formed along the first direction X is provided is hereinafter referred to as a second direction Y. Furthermore, in the present embodiment, a direction orthogonal to the first direction X and the second direction Y is hereinafter referred to as a third direction Z.

  Further, the flow path forming substrate 10 has an opening area narrower than that of the pressure generation chamber 12 on one end portion side in the second direction Y of the pressure generation chamber 12, and the flow path resistance of ink flowing into the pressure generation chamber 12. A supply path or the like for providing the above may be provided.

  Here, in the present embodiment, as shown in FIG. 4, among the plurality of pressure generation chambers 12 arranged in parallel, the pressure generation chamber 12 used for ink discharge is referred to as a pressure generation chamber 12 </ b> A for discharge, The pressure generation chamber 12 that is not used for discharging the liquid is referred to as a dummy pressure generation chamber 12B. In the present embodiment, dummy pressure generation chambers 12B are arranged on both ends of the first direction X in the row of pressure generation chambers 12 arranged in parallel in the first direction X, and the dummy pressure generation chambers 12B A pressure generating chamber 12A for discharge is arranged between them. In the present embodiment, two dummy pressure generating chambers 12B are provided at both ends in the first direction X, respectively. In this embodiment, the discharge pressure generating chamber 12A and the dummy pressure generating chamber 12B are formed in the same shape. Of course, the discharge pressure generation chamber 12A and the dummy pressure generation chamber 12B may have different shapes. However, in the discharge pressure generation chamber 12A arranged in parallel in the first direction X, the first direction X In order to make the characteristics of the pressure generation chamber 12A at the center and the pressure generation chambers 12B at both ends the same, it is preferable that the discharge pressure generation chamber 12A and the dummy pressure generation chamber 12B have the same shape. Further, the number of dummy pressure generating chambers 12B is not particularly limited, and it is sufficient that at least one is provided at both ends of the juxtaposed discharge pressure generating chambers 12A in the juxtaposed direction. It may be provided above.

  As shown in FIGS. 2 and 3, a communication plate 15 is joined to one surface side of the flow path forming substrate 10. The communication plate 15 is joined to a nozzle plate 20 having a plurality of nozzle openings 21 communicating with the pressure generating chambers 12.

  The communication plate 15 is provided with a nozzle communication path 16 that communicates the pressure generation chamber 12 and the nozzle opening 21. The communication plate 15 has a larger area than the flow path forming substrate 10, and the nozzle plate 20 has a smaller area than the flow path forming substrate 10. Thus, cost reduction can be achieved by making the area of the nozzle plate 20 relatively small. As shown in FIG. 5, the nozzle communication path 16 is provided corresponding to the discharge pressure generation chamber 12A in the pressure generation chamber 12, and is not provided in the dummy pressure generation chamber 12B. . Of course, the nozzle communication path 16 may be provided in the dummy pressure generating chamber 12B as long as the ink is not filled in the dummy pressure generating chamber 12B.

As shown in FIGS. 2 and 3, the communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 that constitute a part of the manifold 100.
The first manifold portion 17 is provided through the communication plate 15 in the third direction Z.
Further, the second manifold portion 18 does not penetrate the communication plate 15 in the third direction Z, and opens to the nozzle plate 20 side of the communication plate 15 and is provided halfway in the third direction Z.

  Further, the communication plate 15 is provided with a supply communication passage 19 that communicates with one end portion of the pressure generation chamber 12 in the second direction Y independently for each pressure generation chamber 12. The supply communication path 19 communicates the second manifold portion 18 and the pressure generation chamber 12. In the present embodiment, the supply communication path 19 is provided corresponding to the discharge pressure generation chamber 12A in the pressure generation chamber 12, and is not provided in the dummy pressure generation chamber 12B. As a result, the dummy pressure generation chamber 12B is not filled with ink. As described above, the ink in the dummy pressure generation chamber 12B is not filled with ink, so that the ink in the dummy pressure generation chamber 12B is thickened and solidified, and the dummy pressure generation chamber 12 and the discharge pressure generation chamber 12A. It is possible to suppress the change in the rigidity of the partition wall between them, that is, the bending characteristics. Further, it is possible to prevent the ink that has been thickened and solidified in the dummy pressure generation chamber 12B from entering the discharge pressure generation chamber 12A and causing a discharge failure. Further, if the dummy pressure generation chamber 12B is filled with ink, as will be described in detail later, when driving is performed by applying a drive potential to the dummy piezoelectric actuator 300B corresponding to the dummy pressure generation chamber 12B. Ink pressure fluctuations are transmitted into the manifold 100, which may affect the discharge pressure generation chamber 12A and affect the discharge characteristics of the ink droplets. If the dummy pressure generation chamber 12B is not filled with ink, it is possible to suppress the influence on the discharge pressure generation chamber 12A. Of course, the second manifold portion 18 and the like may be provided only in a region corresponding to the discharge pressure generation chamber 12A so that the manifold 100 does not reach the dummy pressure generation chamber 12B. In this case, even if the supply communication path 19 is provided in the dummy pressure generation chamber 12B, the ink in the manifold 100 is not filled in the dummy pressure generation chamber 12B.

  In the nozzle plate 20, nozzle openings 21 communicating with the pressure generation chambers 12 through the nozzle communication passages 16 are formed. That is, the nozzle openings 21 that eject ink that is the same type of liquid are juxtaposed in the first direction X, and the row of nozzle openings 21 juxtaposed in the first direction X is the second direction. Two rows are formed in Y. In the present embodiment, as shown in FIG. 5, the nozzle opening 21 is provided in communication only with the pressure generation chamber 12A for discharge. That is, the nozzle opening 21 is not provided corresponding to the dummy pressure generation chamber 12B. This eliminates unnecessary processing of the nozzle plate 20 and suppresses problems caused by ink or the like adhering to the nozzle openings 21 from which ink droplets provided corresponding to the dummy pressure generating chambers 12B are not ejected. Can do. For example, when the ink adhering to the nozzle opening 21 where ink droplets are not ejected is dried and solidified, and the liquid ejection surface where the nozzle opening 21 is opened is wiped with a blade made of an elastic material, the solidified ink is applied to the blade. There is a possibility that a discharge failure may occur due to adhesion and imprinting into the discharge nozzle opening 21. Of course, dummy nozzle openings 21 that are not used for discharge may be provided on both sides of the discharge nozzle openings 21 in the parallel arrangement direction. By providing the dummy nozzle openings 21 in this way, among the nozzle openings 21 used for ejection, the processing conditions can be made uniform between the nozzle openings 21 at the center in the juxtaposition direction and the nozzle openings 21 at both ends. Thus, variation in processing accuracy can be suppressed. That is, the processing conditions of the nozzle opening 21 to be processed, that is, the meat approaching, depending on whether the nozzle opening 21 having the adjacent nozzle opening 21 is processed or the nozzle opening 21 having no adjacent nozzle opening 21 is processed. This is because there is a possibility that the processing accuracy may vary due to whether or not the adjacent influences such as are different. Of course, when ink is filled in the dummy pressure generation chamber 12B, a nozzle opening 21 communicating with the dummy pressure generation chamber 12B is provided to correspond to the dummy pressure generation chamber 12B described later in detail. When a driving potential is applied to the dummy piezoelectric actuator 300 </ b> B, ink droplets may be ejected from the nozzle opening 21. That is, when the dummy nozzle opening 21 is provided, it is preferable that the dummy pressure generation chamber 12B is not filled with ink.

  On the other hand, as shown in FIGS. 3 and 5, a diaphragm 50 is formed on the surface of the flow path forming substrate 10 opposite to the communication plate 15. In the present embodiment, an elastic film 51 made of silicon oxide provided on the flow path forming substrate 10 side and an insulator film 52 made of zirconium oxide provided on the elastic film 51 are provided as the diaphragm 50. I made it. The liquid flow path such as the pressure generation chamber 12 is anisotropically etched from, for example, the flow path forming substrate 10 on one surface side in the third direction Z, in this embodiment, the surface side to which the communication plate 15 is joined. The other surface of the pressure generating chamber 12 is defined by an elastic film 51. In addition, the diaphragm 50 is not limited to what was mentioned above, For example, you may be comprised only with the elastic film 51 and may be comprised only with the insulator film 52. The diaphragm 50 may have other films in addition to the elastic film 51 and the insulator film 52. Further, the material of the diaphragm 50 is not limited to that described above.

  Further, on the insulator film 52 of the vibration plate 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated and formed by film formation and lithography in this embodiment. 300. Here, the piezoelectric actuator 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric actuator 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric actuator 300 and the second electrode 80 is an individual electrode of the piezoelectric actuator 300. However, there is no problem even if this is reversed for the convenience of the drive circuit 120 and wiring. . In the above-described example, since the first electrode 60 is continuously provided across the plurality of pressure generating chambers 12, the first electrode 60 functions as a part of the diaphragm, but of course, the present invention is not limited thereto. For example, only one of the first electrodes 60 may act as a diaphragm without providing one or both of the elastic film 51 and the insulator film 52 described above.

  In addition, the second electrode 80 of the piezoelectric actuator 300 is connected to the lead electrode 90 that is the lead-out wiring of this embodiment. Specifically, in the second direction Y, the lead electrode 90 is drawn out on the flow path forming substrate 10 from the end portion between the rows of the piezoelectric actuators 300 of the second electrode 80. In the present embodiment, since the diaphragm 50 is provided on the flow path forming substrate 10, the lead electrode 90 is drawn out from the second electrode 80 onto the diaphragm 50. In the present embodiment, as shown in FIG. 4, the common lead electrode 91 drawn from the first electrode 60 is also formed on the first electrode 60. Note that the common lead electrode 91 has substantially the same configuration as the lead electrode 90, and thus a duplicate description is omitted.

  In this embodiment, as shown in FIGS. 4 and 5, the piezoelectric actuator 300 provided corresponding to the discharge pressure generation chamber 12A is referred to as a discharge piezoelectric actuator 300A, and is used as a dummy 12B. The corresponding piezoelectric actuator 300 is referred to as a dummy piezoelectric actuator 300B. In the present embodiment, the ejection piezoelectric actuator 300A corresponds to the first piezoelectric actuator, and the dummy piezoelectric actuator 300B corresponds to the second piezoelectric actuator. That is, in this embodiment, the discharge piezoelectric actuators 300A are arranged in parallel in the first direction X, and two dummy piezoelectric actuators 300B are provided at both ends of the discharge piezoelectric actuator 300A in the parallel arrangement direction. Is provided. The dummy piezoelectric actuator 300B is provided corresponding to the dummy pressure generating chambers 12B, and may be provided according to the number of dummy pressure generating chambers 12B. However, when a plurality of dummy pressure generation chambers 12B are provided at one end of the discharge pressure generation chambers 12A in the juxtaposed direction, at least a dummy pressure generation chamber 12B adjacent to the discharge pressure generation chamber 12A. The dummy piezoelectric actuator 300B may be provided on the other side, and the dummy piezoelectric actuator 300B may not be provided in the other dummy pressure generation chamber 12B.

  As shown in FIG. 4, the lead electrodes 90 drawn from the second electrodes 80 that are the individual electrodes of the dummy piezoelectric actuator 300 </ b> B are connected to each other on the flow path forming substrate 10. In the present embodiment, the lead electrodes 90 drawn from the dummy piezoelectric actuator 300 are connected to both ends of the piezoelectric actuator 300 arranged in parallel in the first direction X, respectively. That is, since two dummy piezoelectric actuators 300B are provided on one end side of the piezoelectric actuators 300 arranged in parallel in the first direction X, the two piezoelectric actuators 300B are pulled out from the two dummy piezoelectric actuators 300B. The two lead electrodes 90 are connected to each other. In addition, since two dummy piezoelectric actuators 300B are provided on the other end side, the two lead electrodes 90 drawn from the two dummy piezoelectric actuators 300B are connected to each other. Thereby, compared with the case where the lead electrode 90 is individually provided for each dummy piezoelectric actuator 300B, the size of the terminal portion connected to the wiring substrate of the lead electrode 90 can be reduced, and the flow path forming substrate 10 can be reduced. Can be miniaturized.

  Of course, the lead electrode 90 of the dummy piezoelectric actuator 300B is not limited to this, and the lead electrode of the dummy piezoelectric actuator 300B provided at both ends of the piezoelectric actuator 300 arranged in parallel in the first direction X, respectively. 90 may be connected. Further, in this embodiment, two rows in which the piezoelectric actuators 300 are arranged in parallel in the first direction X are formed in two rows in the second direction Y, and are provided at one end of the two rows of piezoelectric actuators 300. The lead electrodes 90 of the dummy piezoelectric actuator 300B may be connected to each other. Thereby, the area of the terminal part connected to the wiring board 121 can be reduced, and further size reduction can be achieved. That is, the lead electrode 90 drawn from each second electrode 80 of the dummy piezoelectric actuator 300B provided on one flow path forming substrate 10 should be connected as much as possible in consideration of the limitation of the routing. The formation substrate 10 can be downsized. As will be described in detail later, as the number of dummy piezoelectric actuators 300B connected by the lead electrodes 90 is increased, a common switch connected to the dummy piezoelectric actuators 300B provided in the drive circuit 120 serving as a head controller. The number of 236B can be further reduced.

  As shown in FIGS. 3 and 6, a drive circuit 120, which is a head controller such as a drive IC, is provided at the other end of the lead electrode 90 opposite to the one end connected to the second electrode 80. The connection wiring 122 of the mounted wiring board 121 is electrically connected. In addition, the connection method of the connection wiring 122 of the wiring board 121 and the lead electrode 90 is not specifically limited, For example, anisotropic conductive adhesive (ACP, ACF), nonconductive adhesive (NCP), solder And welding using a metal such as

  Here, the wiring board 121 is provided with a connection wiring 122A connected to the ejection piezoelectric actuator 300A and a connection wiring 122B connected to the dummy piezoelectric actuator 300B. The connection wiring 122A connected to the discharge piezoelectric actuator 300A is provided independently for each piezoelectric actuator 300A. Since the dummy piezoelectric actuator 300B is provided with the lead electrodes 90 of two or more piezoelectric actuators 300B connected as described above, the two dummy piezoelectric actuators to which the lead electrodes 90 are connected are provided. A connection wiring 122B is provided for each 300B. That is, one connection wiring 122B is not provided for one dummy piezoelectric actuator 300B. Thereby, the number of connection wirings 122B provided on the wiring board 121 can be reduced, and the wiring board 121 can be downsized.

  Further, since the number of connection wirings 122B can be reduced, the number of switches for connection wirings 122B inside the drive circuit 120, which will be described in detail later, can be reduced, and the drive circuit 120 can be downsized. it can.

  As shown in FIGS. 2 and 3, a protective substrate 30 having substantially the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 on the piezoelectric actuator 300 side. The protective substrate 30 has a holding portion 31 that is a space for protecting the piezoelectric actuator 300. The protective substrate 30 is provided with a through-hole 32 that penetrates in the thickness direction (the stacking direction of the flow path forming substrate 10 and the protective substrate 30). An end of the lead electrode 90 opposite to the end connected to the second electrode 80 is formed in the through hole 32, and the connection wiring 122 of the wiring substrate 121 and the lead electrode 90 are connected in the through hole 32. Has been.

  In addition, a case member 40 is fixed to the head main body 11 having such a configuration. The case member 40 defines a manifold 100 communicating with the plurality of pressure generating chambers 12 together with the head main body 11. The case member 40 has substantially the same shape as the communication plate 15 described above in a plan view, and is bonded to the protective substrate 30 and is also bonded to the communication plate 15 described above. Specifically, the case member 40 has a recess 41 having a depth in which the flow path forming substrate 10 and the protective substrate 30 are accommodated on the protective substrate 30 side. The concave portion 41 has an opening area larger than the surface of the protective substrate 30 bonded to the flow path forming substrate 10. The opening surface on the nozzle plate 20 side of the recess 41 is sealed by the communication plate 15 in a state where the flow path forming substrate 10 and the like are accommodated in the recess 41. As a result, a third manifold portion 42 is defined by the case member 40 and the head body 11 on the outer peripheral portion of the flow path forming substrate 10. The manifold 100 of this embodiment is configured by the first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15, and the third manifold portion 42 defined by the case member 40 and the head body 11. It is configured.

  In addition, as a material of case member 40, resin, a metal, etc. can be used, for example. Incidentally, the case member 40 can be mass-produced at low cost by molding a resin material.

  A compliance substrate 45 is provided on the surface of the communication plate 15 where the first manifold portion 17 and the second manifold portion 18 open. The compliance substrate 45 seals the opening on the liquid ejection surface side of the first manifold portion 17 and the second manifold portion 18.

  In this embodiment, the compliance substrate 45 includes a sealing film 46 and a fixed substrate 47. The sealing film 46 is made of a flexible thin film (for example, a thin film having a thickness of 20 μm or less formed of polyphenylene sulfide (PPS) or stainless steel (SUS)), and the fixed substrate 47 is made of stainless steel ( It is formed of a hard material such as a metal such as SUS. Since the region of the fixed substrate 47 facing the manifold 100 is an opening 48 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 46. The compliance portion 49 is a flexible portion.

  The case member 40 is provided with an introduction path 44 that communicates with the manifold 100 and supplies ink to each manifold 100. The case member 40 is provided with a connection port 43 that communicates with the through hole 32 of the protective substrate 30 and through which the wiring substrate 121 is inserted.

  In the ink jet recording head 1 having such a configuration, when ink is ejected, the ink is taken in from the liquid storage means via the introduction path 44 and the inside of the flow path is filled with ink from the manifold 100 to the nozzle opening 21. Thereafter, according to a signal from the drive circuit 120, a voltage is applied to each piezoelectric actuator 300 corresponding to the pressure generating chamber 12, so that the diaphragm 50 is bent and deformed together with the piezoelectric actuator 300. As a result, the pressure in the pressure generating chamber 12 is increased and ink droplets are ejected from the predetermined nozzle openings 21.

Here, the control system of the ink jet recording apparatus I including the ink jet recording head 1 of the present embodiment will be described in detail. FIG. 7 is a block diagram showing a control configuration of the ink jet recording head.
As shown in FIG. 7, the ink jet recording apparatus I according to the present embodiment is schematically configured by a printer controller 200 and a print engine 201.

  The printer controller 200 includes an external interface 202 (hereinafter referred to as an external I / F 202), a RAM 203 that temporarily stores various data, a ROM 204 that stores a control program, a control unit 205 that includes a CPU, and the like. , An oscillation circuit 206 that generates a clock signal, a drive signal formation circuit 207 that generates a drive signal to be supplied to the ink jet recording head 1, and a power generation that generates a power source for use in the drive signal formation circuit 207 A unit 208 and an internal interface 209 (hereinafter referred to as an internal I / F 209) that transmits dot pattern data (bitmap data) or the like developed based on a drive signal or print data to the print engine 201. .

  The external I / F 202 receives, for example, print data composed of character codes, graphic functions, image data, and the like from a host computer (not shown). Further, a busy signal (BUSY) and an acknowledge signal (ACK) are output to the host computer or the like through the external I / F 202. The RAM 203 functions as a reception buffer 210, an intermediate buffer 211, an output buffer 212, and a work memory (not shown). The reception buffer 210 temporarily stores print data received by the external I / F 202, the intermediate buffer 211 stores intermediate code data converted by the control unit 205, and the output buffer 212 stores dot pattern data. . This dot pattern data is constituted by pixel data obtained by decoding (translating) gradation data.

  The ROM 204 stores font data, graphic functions and the like in addition to a control program (control routine) for performing various data processing. The control unit 205 reads the print data in the reception buffer 210 and stores the intermediate code data obtained by converting the print data in the intermediate buffer 211. Further, the intermediate code data read from the intermediate buffer 211 is analyzed, and the intermediate code data is developed into dot pattern data by referring to the font data and graphic functions stored in the ROM 204. Then, the control unit 205 stores the developed dot pattern data in the output buffer 212 after performing necessary decoration processing.

  If dot pattern data corresponding to one line of the ink jet recording head 1 is obtained, the dot pattern data for one line is output to the ink jet recording head 1 through the internal I / F 209. When dot pattern data for one line is output from the output buffer 212, the developed intermediate code data is erased from the intermediate buffer 211, and the development process for the next intermediate code data is performed.

In addition, the power generation unit 208 supplies the drive signal forming circuit 207 with drive power that becomes a drive potential having a drive waveform, which will be described in detail later.
Then, the drive signal forming circuit 207 generates a drive signal (COM) based on the drive power generated by the power generation unit 208.

  The print engine 201 includes an ink jet recording head 1, a paper feed mechanism 213, and a carriage mechanism 214. The paper feed mechanism 213 includes a transport roller 8 serving as a transport unit, a paper feed motor, and the like, and sequentially feeds the recording sheets S in conjunction with the recording operation of the ink jet recording head 1. That is, the paper feed mechanism 213 moves the recording sheet S relative to the ink jet recording head 1 in the sub-scanning direction.

  The carriage mechanism 214 includes a carriage 3 on which the ink jet recording head 1 can be mounted, and a carriage drive unit that causes the carriage 3 to travel along the main scanning direction. The head 1 is moved in the main scanning direction. The carriage drive unit is composed of the drive motor 6 and the timing belt 7 as described above.

  The ink jet recording head 1 has a large number of nozzle openings 21 along a first direction X, which is the sub-scanning direction, and ink droplets (droplets) from each nozzle opening 21 at a timing defined by dot pattern data or the like. Is discharged. The piezoelectric actuator 300 of the ink jet recording head 1 is supplied with an electrical signal, for example, a drive signal COM or pixel data SI, which will be described later, via the wiring board 121.

Here, the drive circuit 120 mounted on the ink jet recording head 1 will be described in detail with reference to FIG. FIG. 8 is a block diagram showing the drive circuit.
As shown in FIG. 8, the driving circuit 120 includes a first shift register (SR) 230, a second shift register (SR) 231, a first latch circuit 232, a second latch circuit 233, a decoder 234, a control logic 235, a transmission. A switch 236 which is a switch element such as a gate is provided. Each part excluding the control logic 235, that is, the first shift register 230, the second shift register 231, the first latch circuit 232, the second latch circuit 233, the decoder 234, and the switch 236, respectively, is a discharge piezoelectric actuator 300A. It is provided for each. In addition, each part excluding the control logic, that is, the first shift register 230, the second shift register 231, the first latch circuit 232, the second latch circuit 233, the decoder 234, and the switch 236 are the dummy to which the lead electrode 90 is connected. For each dummy piezoelectric actuator 300B, that is, for every two dummy piezoelectric actuators 300B. That is, in this embodiment, each part except the control logic 235 is provided for each lead electrode 90. In this embodiment, the switch 236 connected to the ejection piezoelectric actuator 300A is referred to as an individual switch 236A, and the switch 236 connected to the dummy piezoelectric actuator 300B is referred to as a common switch 236B.

  The drive circuit 120 includes a clock signal CLK, a latch signal LAT, a change signal CH, pixel data SI, and setting data SP as head control signals from the printer controller 200 of the ink jet recording apparatus I through the connection wiring 122 of the wiring board 121. A setting signal including The drive signal 120 is input to the drive circuit 120 from the drive signal forming circuit 207 of the printer controller 200 via the connection wiring of the wiring board 121.

Here, the drive signal COM and various signals will be described in detail with reference to FIG. FIG. 9 is an explanatory diagram of drive signals and various signals.
As illustrated in FIG. 9, the drive signal COM is generated in the first period signal SS1 generated in the period T1 in the repetition period T, the second period signal SS2 generated in the period T2, and the third period generated in the period T3. It has a section signal SS3 and a fourth section signal SS4 generated in the period T4. The first section signal SS1 has a drive pulse PS1. The second interval signal SS2 has a drive pulse PS2, the third interval signal SS3 has a drive pulse PS3, and the fourth interval signal SS4 has a drive pulse PS4. Note that the drive pulse PS1, the drive pulse PS2, and the drive pulse PS3 are applied to the piezoelectric actuator 300 when a large dot is formed, and each has the same waveform. Further, the drive pulse PS1 and the drive pulse PS2 are applied to the piezoelectric actuator 300 when the medium dot is formed. The drive pulse PS1 is applied to the piezoelectric actuator 300 when forming small dots. Further, the drive pulse PS4 is applied when the piezoelectric actuator 300 is vibrated to such an extent that no ink droplet is ejected from the nozzle opening 21.
Here, the drive signal COM is a drive potential in a broad sense, and each of the drive pulse PS1, the drive pulse PS2, the drive pulse PS3, and the drive pulse PS4 included in the drive signal COM is a drive potential.

  The drive pulse PS1 is a waveform for ejecting ink droplets from the nozzle opening 21. The drive pulse PS1 is applied from the state in which the reference potential Vb is maintained to the first potential V1 to expand the pressure generating chamber, and the expansion state is maintained for a predetermined time. An expansion maintaining element P2 for maintaining, a contracting element P3 for contracting the pressure generating chamber 12 by applying from the first potential V1 to the second potential V2, a contraction maintaining element P4 for maintaining the contracted state for a certain time, and a second potential V2 And an expansion return element P5 for returning the pressure generating chamber from the contracted state to the reference volume of the reference potential Vb. The drive pulse PS2 and the drive pulse PS3 have the same waveform as the drive pulse PS1.

  The drive pulse PS4 is based on the vibration expansion element P6 that expands the pressure generating chamber 12 from the reference potential Vb to the third potential V3, the vibration expansion maintaining element P7 that maintains the expansion volume for a certain time, and the expansion volume of the third potential V3. And a vibration return element P8 for returning to the reference volume of the potential Vb. That is, the potential at the start or end of each drive pulse PS1, PS2, PS3, and PS4 becomes the reference potential Vb. This reference potential Vb is set to a potential higher than the ground potential GND.

  These drive signals COM are respectively supplied to switches 236 provided for each piezoelectric actuator 300, in this embodiment, for each discharge piezoelectric actuator 300A and for each lead electrode 90 to which the dummy piezoelectric actuator 300B is connected. Entered. That is, the switch 236 is common to each individual switch 236A provided for each discharge piezoelectric actuator 300A and each lead electrode 90 to which the dummy piezoelectric actuator 300B is connected, that is, common to a plurality of piezoelectric actuators 300B. A switch 236B. The individual switch 236A performs on / off control as to whether or not to apply the drive signal COM to the ejection piezoelectric actuator 300A. By this on / off control, a part of the drive signal COM can be selectively applied to the piezoelectric actuator 300, whereby the dot size can be changed. Further, the drive potential of the drive signal COM can be applied to the dummy piezoelectric actuator 300B by the on / off control of the common switch 236B.

  The latch signal LAT is a signal that defines an ejection cycle in which ink is ejected from the nozzle opening 21 to one pixel, and is a signal that indicates a repetitive cycle T (a period in which the ink jet recording head moves in a section of one pixel). The latch signal LAT is generated by the printer controller 200 and is input to the control logic 235 and the latch circuit (the first latch circuit 232 and the second latch circuit 233).

  The change signal CH is a signal indicating a section in which the drive pulse included in the drive signal COM is applied to the piezoelectric actuator 300. The change signal CH is generated by the printer controller 200 and input to the control logic 235.

  The pixel data SI is a signal indicating whether or not a dot is formed in each pixel, that is, whether or not an ink droplet is ejected from the nozzle opening 21. This pixel data SI is composed of 2 bits for each nozzle opening 21. For example, when the number of nozzles is 180, pixel data SI of 2 bits × 180 is sent from the printer controller 200 every repetition period T. The pixel data SI is input to the first shift register 230 and the second shift register 231. In this embodiment, pixel data SI that does not always eject ink droplets is supplied to the dummy piezoelectric actuator 300B.

  The clock signal CLK is used when pixel data SI, change signal CH, latch signal LAT, etc. sent from the printer controller 200 are set in the control logic 235, each shift register (first shift register 230, second shift register 231), etc. It is a signal used for.

  The control logic 235 generates the selection signal q0 based on predetermined 4-bit data and the change signal CH among the 16-bit setting data SP. Similarly, the selection signals q1 to q3 are generated based on predetermined 4-bit data of the 16-bit setting data SP and the change signal CH. The generated selection signals q0 to q3 are provided for each piezoelectric actuator 300, in this embodiment, for each ejection piezoelectric actuator 300A, and for each of two dummy piezoelectric actuators 300B to which the lead electrode 90 is connected. Each is input to the decoder 234.

  Here, when the pixel data SI indicates small dot formation (in the case of the pixel data “01”), the pixel data “01” is latched, and the selection signal q1 is output as the switch control signal SW. Accordingly, the individual switch 236A is turned on in the period T1, and the individual switch 236A is turned off in the periods T2, T3, and T4. As a result, the drive pulse PS1 of the first section signal of the drive signal COM is applied to the piezoelectric actuator 300, that is, the ejection piezoelectric actuator 300A, and the ejection piezoelectric actuator 300A is driven by the drive pulse PS1. When the piezoelectric actuator 300A is driven according to the drive pulse PS1, small dots are formed on the recording sheet S.

  When the pixel data SI indicates medium dot formation (pixel data “10”), the pixel data “10” is latched and the selection signal q2 is output as the switch control signal SW. Accordingly, the individual switches 236A are turned on in the periods T1 and T2, and the individual switches 236A are turned off in the periods T3 and T4. As a result, the drive pulse PS1 of the first interval signal and the drive pulse PS2 of the second interval signal of the drive signal COM are applied to the piezoelectric actuator 300, that is, the ejection piezoelectric actuator 300A, and the ejection piezoelectric actuator 300A is driven. Driven by the pulse PS1 and the drive pulse PS2. When the piezoelectric actuator 300A is driven according to the drive pulse PS1 and the drive pulse PS2, medium dots are formed on the recording sheet S.

  When the pixel data SI indicates large dot formation (pixel data “11”), the pixel data “11” is latched, and the selection signal q3 is output as the switch control signal SW. Accordingly, the individual switches 236A are turned on in the periods T1, T2, and T3, and the individual switches 236A are turned off in the period T4. As a result, the driving pulse PS1 of the first section signal, the driving pulse PS2 of the second section signal, and the driving pulse PS3 of the third section signal of the driving signal COM are applied to the piezoelectric actuator 300, that is, the ejection piezoelectric actuator 300A. The ejection piezoelectric actuator 300A is driven by the drive pulse PS1, the drive pulse PS2, and the drive pulse PS3. When the piezoelectric actuator 300A is driven according to the drive pulse PS1, the drive pulse PS2, and the drive pulse PS3, a large dot is formed on the recording sheet S.

  When the pixel data SI indicates no dot formation (pixel data “00”), the pixel data “00” is latched, and the selection signal q0 is output as the switch control signal SW. Accordingly, the switch 236 (individual switch 236A, common switch 236B) is turned on in the period T4, and the switch 236 is turned off in the periods T1, T2, and T3. As a result, the drive pulse PS4 of the fourth section signal of the drive signal COM is applied to the piezoelectric actuator 300, and the piezoelectric actuator 300 is driven by the drive pulse PS4. When the ejection piezoelectric actuator 300A is driven in accordance with the drive pulse PS4, pressure fluctuations occur such that ink droplets are not ejected from the nozzle openings 21, and the ink meniscus in the nozzle openings 21 vibrates.

  Here, the pixel data “00” is applied to the ejection piezoelectric actuator 300A and the dummy piezoelectric actuator 300B that do not form dots during printing. In other words, in the present embodiment, the pixel data SI and the setting data SP from the printer controller 200 are data that does not eject ink droplets to the common switch 236B connected to the dummy piezoelectric actuator 300B. In the embodiment, data indicating that dots are not formed during printing is given, and a driving potential similar to that when dots are not formed is applied to the dummy piezoelectric actuator 300B. That is, of the piezoelectric actuators 300 arranged in parallel in the first direction X, two dummy piezoelectric actuators 300B are provided at each of the end portions in the juxtaposed direction, and the two piezoelectric actuators 300B provided at each end portion are provided. The same drive pulse PS4 is applied to the dummy piezoelectric actuator 300B via the common switch 236B. Thus, by providing the common switch 236B for the dummy piezoelectric actuator 300B to which the lead electrode 90 is connected, it is not necessary to provide the switch 236B individually for each dummy piezoelectric actuator 300B, and the drive circuit 120 is provided. Can be miniaturized. That is, when an individual switch 236A is provided for each dummy piezoelectric actuator 300B, the drive circuit 120 is increased in size. That is, since it is only necessary to always apply the same drive potential, that is, the drive pulse PS4 in this embodiment, to the plurality of dummy piezoelectric actuators 300B, it is possible to share the connection wiring 122B and share the switch 236B. it can. In the present embodiment, a plurality of dummy piezoelectric actuators 300B can be connected by lead electrodes 90 to reduce the size of the flow path forming substrate 10, and a switch 236B common to the plurality of dummy piezoelectric actuators 300B can be provided. By connecting, the drive circuit 120 can be downsized. In addition, since the number of switches 236 can be reduced, heat generation of the drive circuit 120 can also be suppressed. Furthermore, since the number of switches 236 can be reduced, the number of connection wirings 122B of the wiring board 121 can also be reduced, and the wiring board 121 can be downsized. Incidentally, as the number of dummy piezoelectric actuators 300B connected by the lead electrodes 90 is increased, the number of common switches 236B connected to the dummy piezoelectric actuators 300B provided in the drive circuit 120 as the head controller is further reduced. Therefore, it is preferable to connect the lead electrodes 90 drawn from the plurality of dummy piezoelectric actuators 300 to reduce the number of common switches 236B. That is, two rows of piezoelectric actuators 300 arranged in parallel in the first direction X are provided on one flow path forming substrate 10, and four dummy piezoelectric actuators 300 </ b> B are provided for each row of piezoelectric actuators 300. If the lead electrodes 90 of a total of eight dummy piezoelectric actuators 300B are connected to each other, the drive circuit 120 may be provided with only one common switch element 236B. Further downsizing can be achieved.

  Note that “during printing in which a driving potential is applied to the dummy piezoelectric actuator 300B” means that ink droplets are being ejected from the nozzle openings 21 corresponding to the ejection piezoelectric actuator 300A, and the ejection piezoelectric actuator 300A. The time during which an ink droplet is ejected from the nozzle opening 21 corresponding to the period is a period in which the drive potential is applied to the ejection piezoelectric actuator 300A.

  Further, the drive potential not used for ink droplet ejection is changed to the dummy piezoelectric actuator 300B without applying a drive signal that changes the drive potential used for ink droplet ejection, that is, the drive pulses PS1 to PS3. Since the drive pulse PS4, which is a drive signal, is applied, a change amount of the drive potential used for ejection, that is, a drive signal having a large slope is supplied to the connection wiring 122 common to the plurality of dummy piezoelectric actuators 300B. This is unnecessary, and it is possible to suppress an excessive current from flowing through the connection wiring 122B, the lead electrode 90, and the like between the switch 236B and the dummy piezoelectric actuator 300B.

  As described above, during printing, that is, while ink droplets are ejected from the ejection piezoelectric actuator 300A, the drive potential PS is applied to the dummy piezoelectric actuator 300B by applying the drive pulse PS4 to the dummy piezoelectric actuator 300B. doing. Accordingly, the dummy piezoelectric actuator 300B is tensioned to support the partition wall between the dummy pressure generation chamber 12B and the discharge pressure generation chamber 12A from the side, that is, the discharge pressure generation chamber 12A side. Will be pressed. As a result, even if the internal pressure of the discharge pressure generation chamber 12A increases, the partition wall can be prevented from being bent and deformed toward the dummy pressure generation chamber 12B. For this reason, the pressure loss from the pressure generation chamber 12A for discharge to the dummy pressure generation chamber 12B can be reduced. In addition, since the partition between the piezoelectric actuator 300A for ejection and the piezoelectric actuator 300B for dummy is supported by the tensioned piezoelectric actuator 300B, the rigidity of the partition is higher than that of the structure in which the dummy pressure generation chamber 12B is not provided. It can suppress becoming high too much. Therefore, the deformation degree of the partition wall on the dummy pressure generation chamber 12B side and the deformation of the partition wall on the other pressure generation chamber 12A side when the pressure fluctuation occurs in the discharge pressure generation chamber 12A adjacent to the dummy pressure generation chamber 12B. The degree can be set to the same level. As a result, the amount of pressure loss due to the propagation of pressure fluctuations can be made equal in the pressure generation chamber 12 at the end in the juxtaposed direction and the other pressure generation chambers 12A such as the central portion. As a result, the discharge characteristics such as the flying speed of the ink droplets discharged from the discharge pressure generation chambers 12A arranged in parallel can be made uniform. For this reason, it becomes possible to cope with the high density of the nozzle openings 21 (pressure generation chamber 12) and the miniaturization of the ink jet recording head. Further, it is also suitable when the flow path forming substrate 10 forming the pressure generating chamber 12 is made from a material having relatively low rigidity such as a silicon single crystal substrate.

  In the present embodiment, an ink droplet is ejected from the nozzle opening 21 corresponding to the ejection piezoelectric actuator 300A during printing, that is, the drive pulse PS4 applied when the ejection piezoelectric actuator 300A does not form dots. Meanwhile, the head control signal can be prevented from being enlarged by applying it to the dummy piezoelectric actuator 300B. That is, when a switch 236 is provided for each dummy piezoelectric actuator 300B, a head control signal such as pixel data SI indicating whether or not an ink droplet is to be ejected is required for each switch 236. By connecting a plurality of dummy piezoelectric actuators 300B to a common switch 236B, head control signals such as pixel data SI indicating whether or not ink droplets are to be ejected can be reduced. And high-speed printing can be realized.

  In addition, a drive signal (drive pulse PS4) that is a drive potential not used for ejection can be applied to the dummy piezoelectric actuator 300B simply by changing the setting signal including the pixel data SI and the setting data SP. The circuit configuration of the drive circuit 120 is simplified. Of course, since it is only necessary to apply a driving potential to the dummy piezoelectric actuator 300B during printing, only the reference potential Vb that does not include the driving pulse PS4 that is a fine vibration pulse may be applied. In order to apply only such a reference potential Vb, a period T5 in which only the reference potential Vb is applied may be added to the drive signal COM described above, but the repetition period T becomes longer. This is not preferable because there is a risk of losing. For example, the drive signal forming circuit 207 includes the first drive signal COM1 that is the same as the drive signal COM that is applied to the ejection piezoelectric actuator 300A and the second drive that includes at least the reference potential Vb that is applied to the dummy piezoelectric actuator 300B. By generating the signal COM2 and applying the second drive signal COM2 to the dummy piezoelectric actuator 300B during printing, a suitable drive potential can be applied to the dummy without increasing the repetition period T. It can also be selectively applied to the piezoelectric actuator 300B. However, when the first drive signal COM1 and the second drive signal COM2 are used as described above, the drive circuit 120 needs to have a circuit configuration capable of selecting the first drive signal COM1 and the second drive signal COM2. There is a possibility that the circuit configuration becomes complicated.

  Furthermore, since it is only necessary to apply a drive potential to the dummy piezoelectric actuator 300B, the drive potential PS is not applied to the dummy piezoelectric actuator 300B without applying the drive pulse PS4 included in the drive signal COM. May be. That is, as shown in FIG. 10, a dummy drive signal formation circuit 215 is provided in the printer controller 200, and the dummy drive signal formation circuit 215 is caused to generate a dummy drive signal including only the reference potential Vb. May be applied directly to the dummy piezoelectric actuator 300B. As a result, the drive circuit 120 does not require the common switch 236B connected to the plurality of dummy piezoelectric actuators 300B, and the drive circuit 120 can be further reduced in size and heat generation can be suppressed. Further, in the configuration shown in FIG. 10, since the drive potential can be applied to the dummy piezoelectric actuator 300B without using the switch 236 of the drive circuit 120, the number of pixel data can be further reduced, thereby realizing high-speed printing. it can. Furthermore, since the common switch 236B is unnecessary, the circuit configuration of the drive circuit 120 can be further simplified. Further, by using the wiring board 121 connected to the dummy piezoelectric actuator 300B separately from the wiring board 121, the wiring board 121 does not require the connection wiring 122B connected to the dummy piezoelectric actuator 300B. Further miniaturization and cost reduction of the substrate 121 can be achieved.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above. For example, in the first embodiment described above, the drive pulse PS4 is applied as the drive potential to the dummy piezoelectric actuator 300B. However, in the dummy pressure generation chamber 12B corresponding to the dummy piezoelectric actuator 300B, ink is supplied. Therefore, a drive signal including ejection drive pulses PS1 to PS3 may be applied to the dummy piezoelectric actuator 300B. However, as described above, a drive waveform having a large amount of change used for ejection of the connection wiring 122B, the lead electrode 90, and the like between the dummy piezoelectric actuator 300B and the common switch 236B flows, so that an excessive current may flow. There is.
In the above-described first embodiment, the configuration in which the ink is not filled in the dummy pressure generation chamber 12B is illustrated. However, the present invention is not particularly limited thereto, and the ink may be filled.

  Further, in the first embodiment described above, the reference potential Vb or the reference potential Vb including the micro-vibration driving pulse PS4 is applied to the dummy piezoelectric actuator 300B. However, the present invention is not limited to this. A potential different from Vb may be applied to the dummy piezoelectric actuator 300B. However, by applying the reference potential Vb to the dummy piezoelectric actuator 300B, it is not necessary to form a potential other than the reference potential Vb in the drive signal forming circuit 207, the dummy drive signal forming circuit 215, etc., and the circuit configuration is simplified. Can be

  In the first embodiment described above, the thin film piezoelectric actuator 300 has been described as the pressure generating means for causing a pressure change in the pressure generating chamber 12, but the present invention is not particularly limited thereto. For example, a green sheet is attached. It is possible to use a thick film type piezoelectric actuator formed by such a method, a longitudinal vibration type piezoelectric actuator in which piezoelectric materials and electrode forming materials are alternately stacked and expanded and contracted in the axial direction.

  Further, in the above-described ink jet recording apparatus I, the ink jet recording head 1 (head unit II) is mounted on the carriage 3 and moves in the main scanning direction. However, the present invention is not particularly limited to this. The present invention can also be applied to a so-called line-type recording apparatus in which the recording head 1 is fixed and printing is performed simply by moving the recording sheet S such as paper in the sub-scanning direction.

Furthermore, the present invention is intended for a wide range of liquid jet heads in general, for example, for manufacturing recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. The present invention can also be applied to a coloring material ejecting head, an organic EL display, an electrode material ejecting head used for forming electrodes such as an FED (field emission display), a bioorganic matter ejecting head used for biochip manufacturing, and the like.
Further, although the ink jet recording apparatus I has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.

  I ink jet recording apparatus (liquid ejecting apparatus), II ink jet recording head unit (liquid ejecting head unit), 1 ink jet recording head (liquid ejecting head), 10 flow path forming substrate, 12 pressure generating chamber, 12A for discharging Pressure generating chamber, 12B dummy pressure generating chamber, 15 communication plate, 21 nozzle opening, 30 protective substrate, 40 case member, 50 vibration plate, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 121 wiring board, 122, 122A, 122B connection wiring, 200 printer controller, 236 switch (switch element), 236A individual switch (switch element), 236B common switch (switch element) 300 piezoelectric actuator, a piezoelectric actuator for 300A discharge, the piezoelectric actuator for 300B dummy

Claims (7)

A piezoelectric actuator that causes a pressure change in the pressure generating chamber;
A switch element for controlling whether or not to apply a driving potential for driving the piezoelectric actuator to the piezoelectric actuator,
A first piezoelectric actuator among the plurality of piezoelectric actuators ejects liquid from a nozzle opening corresponding to the pressure generating chamber based on a driving potential applied by control of the switch element,
Among the plurality of actuators, the second piezoelectric actuator is applied with a driving potential under the control of the switch element while the liquid is ejected from the first piezoelectric actuator.
There are a plurality of the second piezoelectric actuators,
The liquid ejecting head, wherein the plurality of second piezoelectric actuators are supplied with a driving potential from a common switch element. The switch element applies a drive signal in which the drive potential is changed to the first piezoelectric actuator, and ejects liquid from the nozzle opening communicating with the pressure generation chamber corresponding to the first piezoelectric actuator,
The common switch element does not eject liquid from the nozzle opening communicating with the pressure generation chamber corresponding to the second piezoelectric actuator without applying the driving signal to the second piezoelectric actuator. The liquid jet head according to claim 1. A piezoelectric actuator that causes a pressure change in the pressure generating chamber;
A switch element for controlling whether or not to apply a driving potential for driving the piezoelectric actuator to the piezoelectric actuator,
A first piezoelectric actuator among the plurality of piezoelectric actuators ejects liquid from a nozzle opening corresponding to the pressure generating chamber based on a driving potential applied by control of the switch element,
The liquid ejecting head, wherein a driving potential is applied to the second piezoelectric actuator among the plurality of actuators without controlling the switch element while the liquid is ejected from the first piezoelectric actuator.   The liquid ejecting head according to claim 3, wherein the drive potential applied to the second piezoelectric actuator without being controlled by the switch element is a reference potential.   The liquid ejecting head according to claim 1, wherein the pressure generation chamber corresponding to the second piezoelectric actuator is not filled with liquid.   6. The liquid ejection according to claim 1, wherein the pressure generation chamber corresponding to the second piezoelectric actuator is not provided with the nozzle opening corresponding to the pressure generation chamber. head.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

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