JP2018103551A - Liquid jet device and method for controlling liquid jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet device that can suppress liquid-jetting failures even in a jetting state where shortage of supply of liquid to a common liquid chamber may be induced, and a method for controlling a liquid jet device.SOLUTION: A nozzle group has a first nozzle (30a) and a second nozzle (30b) different form the first nozzle. A driving pulse generating circuit generates first driving pulse (Pd) and second driving pulse (Pv2). The first driving pulse is driving pulse for jetting liquid from the first nozzle, and the second driving pulse is driving pulse for generating pressure vibrations in liquid in the second nozzle when a jetting state of liquid in each nozzles in the nozzle group satisfies a specific condition for inducing shortage of supply of liquid to a common liquid chamber.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a liquid ejecting apparatus including a liquid ejecting head having a nozzle group including a plurality of nozzles, and a method for controlling the liquid ejecting apparatus.

  The liquid ejecting apparatus includes a liquid ejecting head and ejects (discharges) various liquids from the liquid ejecting head. As this liquid ejecting apparatus, for example, there is an image recording apparatus such as an ink jet printer or an ink jet plotter, but recently, various types of manufacturing have been made by taking advantage of the ability to accurately land a very small amount of liquid on a predetermined position. It is also applied to devices. For example, a display manufacturing apparatus that manufactures color filters such as liquid crystal displays, an electrode forming apparatus that forms electrodes such as organic EL (Electro Luminescence) displays and FEDs (surface emitting displays), and chips that manufacture biochips (biochemical elements) Applied to manufacturing equipment. The recording head for the image recording apparatus ejects liquid ink, and the color material ejecting head for the display manufacturing apparatus ejects solutions of R (Red), G (Green), and B (Blue) color materials. The electrode material ejecting head for the electrode forming apparatus ejects a liquid electrode material, and the bioorganic matter ejecting head for the chip manufacturing apparatus ejects a bioorganic solution.

  This type of liquid ejecting head includes a liquid flow path from an inlet to a common liquid chamber (also called a reservoir or a manifold) and a pressure chamber to a nozzle, and an actuator (driving element) such as a piezoelectric element or a heating element. By driving this, pressure vibration is generated in the liquid in the nozzle and the pressure chamber, and droplets are ejected from the nozzle using this pressure vibration. When an operation is performed in which a large amount of liquid is simultaneously ejected from a plurality of nozzles in the liquid ejecting head, the supply of liquid from the upstream side to the common liquid chamber cannot catch up due to an increase in pressure loss in the liquid flow path, Thereby, the liquid may not be normally ejected from the nozzle. In response to such a problem, when the liquid ejection state in the liquid ejection head becomes a situation where there is a possibility that insufficient supply of the liquid may occur, a standby time during which the liquid is not ejected is provided, and the liquid as described above Has been proposed (see, for example, Patent Document 1).

JP 2010-228349 A

  However, there is a problem that the overall processing speed (throughput) of the liquid ejecting apparatus is reduced by providing the standby time as described above. Further, depending on the structure of the liquid ejecting head, this may be caused by a sudden change in the liquid ejecting state such as when the above-described standby time is provided from a situation where the liquid ejecting amount is relatively large. As a result, a large pressure oscillation may occur in the liquid in the common liquid chamber. Then, when the liquid ejection operation is restarted next time, there is a possibility that insufficient supply of liquid may occur depending on the phase of the pressure oscillation of the common liquid chamber.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress liquid ejection failure even in an ejection situation that may induce a shortage of liquid supply to the common liquid chamber. The present invention provides a liquid ejecting apparatus capable of performing the above and a method for controlling the liquid ejecting apparatus.

The liquid ejecting apparatus of the present invention has been proposed to achieve the above object, and a plurality of nozzle groups each composed of a plurality of nozzles and a plurality of nozzles corresponding to each nozzle are provided, and the liquid in the corresponding nozzles is provided. A liquid ejecting head having a common liquid chamber to which a liquid to be supplied to each nozzle and a driving element that causes pressure vibration to be supplied to the nozzle, and
A drive pulse generation circuit for generating a drive pulse for driving the drive element;
A liquid ejecting apparatus comprising:
The nozzle group includes a first nozzle and a second nozzle,
The drive pulse generation circuit generates a first drive pulse and a second drive pulse,
The first driving pulse is a driving pulse that is applied to the driving element corresponding to the first nozzle and ejects liquid from the first nozzle,
The second drive pulse corresponds to the second nozzle when the liquid ejection state of each nozzle in the nozzle group satisfies a specific condition that induces insufficient supply of liquid to the common liquid chamber. The driving pulse is applied to the driving element to cause pressure oscillation in the liquid in the second nozzle.

  According to the present invention, when the liquid ejection state of each nozzle in the nozzle group satisfies a specific condition that induces insufficient supply of liquid to the common liquid chamber, the second driving element corresponding to the second nozzle Since the drive pulse is applied to cause pressure oscillation in the liquid in the second nozzle, the liquid on the second nozzle side tends to be drawn into the common liquid chamber side as the liquid from the first nozzle is consumed. Even if a force acts, pressure vibration that resists (cancels) the force can be generated in the second nozzle. For this reason, even if it is a case where the injection condition in each nozzle satisfy | fills the said conditions, it is suppressed that air is drawn in into a liquid flow path from a 2nd nozzle. As a result, liquid injection failure is suppressed even in an injection situation where there is a risk of inadequate supply of liquid to the common liquid chamber, such as intermittent injection operation at high DUTY. It becomes possible to do. As a result, it is possible to perform the ejection operation without taking measures such as reducing the capacity of the liquid ejection device, such as lowering the DUTY or separately providing a standby time.

In the above configuration, the drive pulse generation circuit can generate a vibration drive pulse that is applied to the drive element corresponding to the nozzle that is not ejected of liquid and causes pressure vibration in the liquid in the nozzle. ,
It is desirable to adopt a configuration in which the second drive pulse is a drive pulse in which pressure vibration generated in the liquid in the nozzle is larger than in the case of the vibration drive pulse.

  According to this configuration, since the force against the force of drawing the liquid into the common liquid chamber is increased in the second nozzle, it is more reliable that air is drawn into the liquid channel from the second nozzle. To be suppressed.

  In the above-described configuration, it is desirable that the second drive pulse is a drive pulse that drives the drive element so as to increase the pressure of the liquid in the second nozzle and push it toward the ejection side. .

  According to this configuration, since the liquid is pushed out to the ejection side in the second nozzle, it is more effectively suppressed that air is drawn into the liquid flow path from the second nozzle.

  In the above configuration, a configuration is adopted in which the pressure vibration of the liquid in the second nozzle caused by the second drive pulse and the pressure vibration generated in association with the ejection of the liquid in the first nozzle are in opposite phases. It is desirable.

  Since the force for drawing the liquid into the common liquid chamber is canceled by the second nozzle, the air is more reliably suppressed from being drawn into the liquid channel from the second nozzle.

  In addition, the present invention is suitable when applied to a configuration in which a part of the common liquid chamber is partitioned by a compliance member having flexibility.

  According to this configuration, in a configuration in which a part of the common liquid chamber is partitioned by the compliance member having flexibility, the pressure vibration is greatly increased by the displacement of the compliance member according to the pressure vibration of the liquid in the common liquid chamber. Therefore, even in a relatively low DUTY, there is a possibility that insufficient supply may be induced. Even in such a configuration, it is possible to effectively suppress liquid ejection failure.

Further, according to the control method of the liquid ejecting apparatus of the present invention, a nozzle group composed of a plurality of nozzles, a plurality of driving elements provided corresponding to each nozzle, and causing pressure vibrations in the liquid in the corresponding nozzle, And a control method for a liquid ejecting apparatus, comprising: a liquid ejecting head having a common liquid chamber to which a liquid to be supplied to each nozzle is supplied; and a drive pulse generating circuit that generates a drive pulse for driving the drive element. ,
While applying the first drive pulse to the drive element corresponding to the first nozzle when ejecting liquid from the first nozzle of the nozzles constituting the nozzle group,
When the liquid ejection state of each nozzle in the nozzle group satisfies a specific condition that induces insufficient supply of liquid to the common liquid chamber, the second nozzle among the nozzles constituting the nozzle group A second drive pulse is applied to the corresponding drive element to cause pressure oscillation in the liquid in the second nozzle.

It is a front view explaining the structure of one form of a liquid ejecting apparatus (printer). 3 is a block diagram illustrating an electrical configuration of the liquid ejecting apparatus. FIG. FIG. 3 is a cross-sectional view of a liquid ejecting head (recording head). FIG. 4 is an enlarged view of a region X in FIG. 3. It is an enlarged view around a compliance section. It is a schematic diagram of the ink flow path from a reservoir to a nozzle. It is a schematic diagram explaining the flow of ink between the nozzle for ejection and the non-ejection nozzle. It is a schematic diagram explaining the change of the ink ejection condition about each nozzle. It is a table | surface which shows the test result about the presence or absence of the countermeasure of an ink supply shortage about an ink ejection condition. It is a wave form diagram of a jetting drive pulse. It is a wave form diagram of the 1st vibration drive pulse. It is a wave form diagram of the 2nd vibration drive pulse. It is the figure which showed the waveform of the pressure vibration produced | generated by the 2nd vibration drive pulse, the timing of the injection drive pulse, and the timing at which the 2nd vibration drive pulse is applied corresponding to each other. It is a schematic diagram explaining the flow of ink between the nozzle for ejection and the non-ejection nozzle. It is a wave form diagram of the modification of the 2nd vibration drive pulse. It is a wave form diagram of the modification of the 2nd vibration drive pulse. It is a wave form diagram of the modification of the 2nd vibration drive pulse. It is a wave form diagram of the modification of the 2nd vibration drive pulse.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following, an ink jet recording apparatus (hereinafter referred to as a printer) will be described as an example of the liquid ejecting apparatus of the invention.

  FIG. 1 is a front view illustrating a configuration of a printer 1 including a recording head 10 which is a kind of liquid ejecting head. FIG. 2 is a block diagram illustrating the electrical configuration of the printer 1. The printer 1 includes a frame 2 and a platen 3 disposed in the frame 2, and a recording sheet, fabric, resin sheet, or the like is placed on the platen 3 by a transport mechanism 4 (see FIG. 2). A recording medium (a kind of liquid landing target) is conveyed. A guide rod 5 is installed in the frame 2 in parallel with the platen 3, and a carriage 6 on which a recording head 10 is mounted is slidably supported on the guide rod 5. The carriage 6 is configured to reciprocate in the main scanning direction perpendicular to the conveyance direction of the recording medium along the guide rod 5 by driving a carriage moving mechanism 7 (see FIG. 2). The printer 1 uses ink (a kind of liquid in the present invention) from a nozzle 30 (see FIG. 3) of the recording head 10 while moving the carriage 6 relative to the recording medium placed on the platen 3 in the main scanning direction. Is ejected to land the ink on the recording medium, thereby forming (recording / printing) a landing pattern such as characters and images.

  An ink cartridge 8 (a type of liquid storage member) that stores ink is detachably mounted on the carriage 6. Examples of the ink include water-based dye ink or pigment ink, organic solvent-based (ecosolvent-based) ink having higher weather resistance than these water-based inks, and photo-curable ink that is cured by irradiation with ultraviolet rays. Well-known various compositions can be used. In the present embodiment, the configuration in which the ink cartridge 8 is mounted on the carriage 6 is illustrated. However, the present invention is not limited to this, and the ink cartridge 8 is disposed on the main body side of the printer 1 and is recorded via the ink supply tube. It is also possible to employ a configuration supplied to the head 10.

  At the home position, which is a non-recording area of the printer 1, a wiping mechanism 11 that wipes the nozzle forming surface (the surface facing the platen 3, see FIG. 3) of the nozzle plate 24 of the recording head 10 mounted on the carriage 6. Is arranged. The wiping mechanism 11 has a wiper 12, and the wiper 12 is configured by an elastic / flexible member such as rubber or elastomer. In the wiping mechanism 11, the wiper 12 is disposed at a position where the tip of the wiper 12 can come into contact with the nozzle forming surface of the recording head 10 during wiping. Then, the nozzle forming surface is wiped by the wiper 12 by relatively moving the wiper 12 in a state where the tip of the wiper 12 is in contact with the nozzle forming surface.

  A capping mechanism 13 is disposed adjacent to the wiping mechanism 11 at or near the home position. The capping mechanism 13 has a cap 14 (a kind of sealing member) made of a tray-like elastic member that can come into contact with the nozzle forming surface of the recording head 10. The capping mechanism 13 is configured such that the space in the cap 14 functions as a sealing space, and can be brought into close contact with the nozzle forming surface with the nozzle 30 of the recording head 10 facing the sealing space. Further, a pump unit 16 (see FIG. 2) is connected to the cap 14 via a waste liquid tube (not shown), and the operation of the pump unit 16 causes the inside of the sealed space of the cap 14 to be negatively charged via the waste liquid tube. Can be compressed. In the cleaning process for eliminating the clogging of the nozzles 30 and the ink flow paths of the recording head 10, the pressure in the sealed space (sealed space) is reduced to a negative pressure while being in close contact with the nozzle forming surface. Ink and bubbles in the head 10 are sucked and discharged into the sealed space of the cap 14.

  As shown in FIG. 2, the printer 1 in this embodiment includes a CPU 17, a storage device 18, a drive signal generation circuit 19 (corresponding to a drive pulse generation circuit in the present invention), an input / output interface 20, a transport mechanism 4, and carriage movement. It has a mechanism 7, a wiping mechanism 11, a capping mechanism 13, a pump unit 16, and a recording head 10. The input / output interface 20 receives a request for a printing operation from the external device side, print setting information, print data (image data), etc., outputs the status information of the printer 1 to the external device, and transmits and receives various data. . The CPU 17 is an arithmetic processing unit for controlling the entire printer, and controls a printing operation (liquid ejection operation) by the recording head 10. The storage device 18 is an element that stores a program for the CPU 17 and data used for various controls, and includes a ROM, a RAM, and an NVRAM (nonvolatile storage element). The drive signal generation circuit 19 generates a drive signal including a drive pulse (described later) for driving the piezoelectric element 31 of the recording head 10 based on waveform data relating to the waveform of the drive signal.

Next, the configuration of the recording head 10 in the present embodiment will be described.
3 is a cross-sectional view of the recording head 10, and FIG. 4 is an enlarged view of a region X in FIG. FIG. 5 is an enlarged view of the periphery of the reservoir 43 in FIG. The recording head 10 according to the present embodiment is a unit in which a plurality of head components such as a fixed plate 23, a nozzle plate 24, a communication plate 25, an actuator substrate 26, a compliance substrate 27, and a holder 28 are laminated and bonded by an adhesive or the like. It has become. In the following description, the stacking direction of the constituent members of the recording head 10 will be described as the vertical direction as appropriate.

  In the present embodiment, the actuator substrate 26 includes a pressure chamber forming substrate 29 in which a pressure chamber 33 communicating with the nozzles 30 formed in the nozzle plate 24 is formed, and a drive element that generates pressure vibration in the ink in each pressure chamber 33. And a protective substrate 32 that protects the pressure chamber forming substrate 29 and the piezoelectric element 31 in a laminated state. A wiring empty portion 40 through which the flexible substrate 39 on which the drive IC 38 is mounted is opened at a substantially central portion in plan view of the protective substrate 32. A lead electrode of the piezoelectric element 31 is disposed in the wiring space 40, and a wiring terminal of the flexible substrate 39 is electrically connected to the lead electrode. A drive signal sent from the drive signal generation circuit 19 is supplied to the piezoelectric element 31 through the flexible substrate 39. The flexible substrate 39 is not limited to the one provided with the drive IC 38, and a configuration in which the drive IC 38 is separately disposed on the protective substrate 32 via a so-called interposer may be employed.

  The pressure chamber forming substrate 29 of the actuator substrate 26 is made of a silicon single crystal substrate. In the pressure chamber forming substrate 29, a plurality of spaces corresponding to the nozzles 30 are provided as spaces for forming the pressure chambers 33. The pressure chamber 33 is a hollow portion that is long in a direction intersecting with the nozzle row (orthogonal in the present embodiment). A nozzle communication port 34 communicates with one end of the pressure chamber 33 in the longitudinal direction, and an individual communication port 35 communicates with the other end. Two rows of pressure chambers 33 are formed on the pressure chamber forming substrate 29 in the present embodiment.

A vibration plate 36 is laminated on the upper surface of the pressure chamber forming substrate 29 (the surface opposite to the communication plate 25 side), and the upper opening of the pressure chamber 33 is sealed by the vibration plate 36. That is, a part of the pressure chamber 33 is partitioned by the diaphragm 36. The vibration plate 36 includes, for example, an elastic film made of silicon dioxide (SiO ₂ ) formed on the upper surface of the pressure chamber forming substrate 29 and an insulator film made of zirconium oxide (ZrO ₂ ) formed on the elastic film. And consist of And the piezoelectric element 31 is laminated | stacked on the area | region corresponding to each pressure chamber 33 on this diaphragm 36, respectively.

  The piezoelectric element 31 of the present embodiment is a so-called bending mode piezoelectric element. For example, the piezoelectric element 31 is formed by sequentially laminating a lower electrode layer, a piezoelectric layer, and an upper electrode layer (all not shown) on the vibration plate 36. The piezoelectric element 31 configured in this manner bends and deforms in the vertical direction when an electric field corresponding to the potential difference between both electrodes is applied between the lower electrode layer and the upper electrode layer. In the present embodiment, two rows of piezoelectric elements 31 are formed corresponding to the rows of pressure chambers 33 formed in two rows. The lower electrode layer and the upper electrode layer extend as lead electrodes from the rows of the piezoelectric elements 31 on both sides to the inside of the wiring space 40 between the rows, and are electrically connected to the flexible substrate 39 as described above. ing.

  The protective substrate 32 is laminated on the vibration plate 36 so as to cover the rows of the piezoelectric elements 31 formed in two rows. Inside the protective substrate 32, a long accommodation space 41 that can accommodate the rows of piezoelectric elements 31 is formed. The accommodation space 41 is a recess formed partway in the height direction of the protective substrate 32 from the lower surface side (the diaphragm 36 side) of the protective substrate 32 toward the upper surface side (the holder 28 side). In the protection substrate 32 in the present embodiment, accommodation spaces 41 are respectively formed on both sides of the wiring vacant portion 40. A communication plate 25 having a larger area than the actuator substrate 26 is joined to the lower surface of the actuator substrate 26.

  Similar to the pressure chamber forming substrate 29, the communication plate 25 is made of a silicon single crystal substrate. In the communication plate 25 in the present embodiment, a nozzle communication port 34 for communicating the pressure chamber 33 and the nozzle 30, a reservoir 43 (a kind of common liquid chamber, also referred to as a manifold) provided in common to each pressure chamber, and The individual communication port 35 communicating the reservoir 43 and the pressure chamber 33 is formed by, for example, anisotropic etching. The reservoirs 43 are empty portions extending along the nozzle row direction, and two reservoirs 43 are formed corresponding to each nozzle row of the nozzle plate 24 in the communication plate 25 in the present embodiment. It is also possible to employ a configuration in which a plurality of reservoirs are provided for one nozzle row, and different types of ink are assigned to the respective reservoirs. The nozzle communication port 34, the individual communication port 35, and the reservoir 43 are formed by anisotropic etching from the lower surface side of the communication plate 25. Ink is introduced into the reservoir 43 through an introduction port 52 of a liquid chamber empty portion 51 provided in the holder 28 as will be described later. A plurality of individual communication ports 35 are formed along the nozzle row direction corresponding to the respective pressure chambers 33. The individual communication port 35 communicates with the end portion on the other side in the longitudinal direction of the pressure chamber 33 (the side opposite to the side communicating with the nozzle communication port 34).

  As shown in FIGS. 4 and 5, the reservoir 43 includes a first reservoir 43 a that communicates with the liquid chamber cavity 51 of the holder 28, and a first reservoir 43 a that communicates with the first reservoir 43 a and the pressure chamber 33. 2 reservoir portions 43b. The first reservoir portion 43 a is an empty portion having an opening having a shape and a size that follows the opening shape on the bottom surface side of the liquid chamber empty portion 51 of the holder 28, and is a portion that penetrates the thickness direction of the communication plate 25. . In the present embodiment, the introduction port 52 of the holder 28 is disposed at a position corresponding to the longitudinal direction of the first reservoir 43a, that is, the center in the nozzle row direction (see FIG. 6). The second reservoir portion 43b is a portion that is recessed from the lower surface side to the middle of the plate thickness direction while leaving the thin portion 43c on the upper surface side of the communication plate 25, and in the nozzle row direction with respect to the first reservoir portion 43a. It is formed adjacent to the intersecting direction (the orthogonal direction in the present embodiment). The second reservoir portion 43b extends along the first reservoir portion 43a from one end of the first reservoir portion 43a to the other end in the nozzle row direction. One end of the second reservoir 43b in the direction intersecting the nozzle row direction communicates with the first reservoir 43a, while the other end of the second reservoir 43b is joined to the communication plate 25. It is formed so as to communicate with individual communication ports 35 communicating with 29 pressure chambers 33. The opening on the lower surface side of the reservoir 43 is sealed with the compliance sheet 44 of the compliance substrate 27.

  A nozzle plate 24 in which a plurality of nozzles 30 are formed is joined to a substantially central portion of the lower surface of the communication plate 25. The nozzle plate 24 in the present embodiment is a plate material having an outer shape smaller than the communication plate 25 and the actuator substrate 26, and is composed of a silicon single crystal substrate. The nozzle plate 24 is located at a position deviated from the opening of the reservoir 43 on the lower surface of the communication plate 25, and the nozzle communication port 34 and the plurality of nozzles 30 communicate with each other in a region where the nozzle communication port 34 is opened. In such a state, it is joined with an adhesive or the like. In the nozzle plate 24 in this embodiment, a total of two nozzle rows (corresponding to the nozzle group in the present invention) in which a plurality of nozzles 30 are arranged are formed. In the present embodiment, one nozzle row is composed of, for example, 400 nozzles 30. The nozzle group is not limited to one in which a plurality of nozzles are arranged in a line, and one in which a plurality of nozzles are arranged in a matrix can also be employed. In short, the nozzle group may be composed of a plurality of nozzles to which liquids are respectively supplied from the same reservoir (common liquid chamber).

  In addition, on the lower surface of the communication plate 25, a compliance substrate 27 having a through-opening 46 having a shape following the outer shape of the nozzle plate 24 formed at the center so as to surround the nozzle plate 24 is joined. The through opening 46 of the compliance substrate 27 communicates with the through hole 23a of the fixing plate 23, and the nozzle plate 24 is arranged inside thereof.

  The compliance substrate 27 is positioned and joined to the lower surface of the communication plate 25 and seals the opening of the reservoir 43 on the lower surface of the communication plate 25. As shown in FIGS. 4 and 5, the compliance substrate 27 in the present embodiment is configured by joining a compliance sheet 44 (a kind of compliance member) and a support plate 45 that supports the compliance sheet 44. The compliance sheet 44 of the compliance substrate 27 is bonded to the lower surface of the communication plate 25 so that the compliance sheet 44 is sandwiched between the communication plate 25 and the support plate 45. The compliance sheet 44 is made of a flexible thin film, for example, a synthetic resin material such as polyphenylene sulfide (PPS). The support plate 45 is formed of a metal material such as stainless steel having higher rigidity and thickness than the compliance sheet 44. In a region of the support plate 45 facing the reservoir 43, a compliance opening 48 is formed by removing a part of the support plate 45 in a shape following the opening of the lower surface of the reservoir 43. For this reason, the opening on the lower surface side of the reservoir 43 is sealed only with the compliance sheet 44 having flexibility. In other words, the compliance sheet 44 defines a part of the reservoir 43.

  A portion corresponding to the compliance opening 48 on the lower surface of the support plate 45 is sealed by the fixing plate 23. Thereby, a compliance space 47 is formed between the flexible region of the compliance sheet 44 and the fixing plate 23 facing the flexible region. The flexible region of the compliance sheet 44 in the compliance space 47 is displaced to the reservoir 43 side or the compliance space 47 side in response to pressure vibration in the ink flow path, particularly in the reservoir 43. Therefore, the thickness of the support plate 45 is determined according to the height required for the compliance space 47.

  The actuator substrate 26 and the communication plate 25 are fixed to the holder 28. The holder 28 has substantially the same shape as the communication plate 25 in a plan view, and an accommodation space 49 for accommodating the actuator substrate 26 is formed on the lower surface side of the holder 28. Then, the lower surface of the holder 28 is sealed by the communication plate 25 in a state where the actuator substrate 26 is accommodated in the accommodation space 49. As shown in FIG. 3, an insertion space 50 that communicates with the accommodation space 49 is formed at a substantially central portion of the holder 28 in plan view. The insertion space 50 communicates with the wiring space 40 of the actuator substrate 26. The flexible board 39 is configured to be inserted into the wiring cavity 40 through the insertion cavity 50. Further, inside the holder 28, a liquid chamber space 51 that communicates with the reservoir 43 of the communication plate 25 is formed on both sides of the insertion space 50 and the accommodation space 49. In addition, on the upper surface of the holder 28, an introduction port 52 communicating with the liquid chamber empty space 51 is opened. Ink sent from the ink cartridge 8 is introduced into the liquid chamber space 51 through the introduction port 52. In other words, the ink sent from the ink cartridge 8 is introduced into the introduction port 52, the liquid chamber space 51, and the reservoir 43, and is supplied from the reservoir 43 to the pressure chambers 33 through the individual communication ports 35.

  The fixed plate 23 is a metal plate material such as stainless steel. In the present embodiment, the fixing plate 23 has a through-hole 23 a having a shape that follows the outer shape of the nozzle plate 24 in order to expose the nozzle 30 formed on the nozzle plate 24 at a position corresponding to the nozzle plate 24. It is formed so as to penetrate the direction. As described above, the through hole 23 a communicates with the through opening 46 of the compliance substrate 27. In this embodiment, the lower surface of the fixed plate 23 in the fixed plate 23 and the exposed portion of the nozzle plate 24 in the through hole 23a constitute a nozzle forming surface.

  In the recording head 10 having the above-described configuration, the drive signal from the drive IC 38 (in the state where the flow path from the liquid chamber empty portion 51 through the reservoir 43 and the pressure chamber 33 to the nozzle 30 is filled with ink. When the piezoelectric element 31 is driven according to the drive pulse), pressure vibration is generated in the ink in the pressure chamber 33, and ink is ejected from a predetermined nozzle 30 by this pressure vibration. Further, the compliance sheet 44 is displaced (bends) in accordance with the pressure vibration generated in the liquid in the ink flow path (inside the reservoir 43) with the recording operation (liquid ejecting operation) of the recording head 10. Pressure oscillation is relieved.

  FIG. 6 is a diagram for explaining the flow of ink and air in the ink flow path (corresponding to the liquid flow path in the present invention), and is a schematic diagram showing a simplified ink flow path from the reservoir 43 to the nozzle 30. is there. FIG. 7 is a schematic diagram for explaining the ink flow between the ejection nozzle 30a (corresponding to the first nozzle in the present invention) and the non-ejection nozzle 30b (corresponding to the second nozzle in the present invention). is there. In the printer 1 according to the present embodiment, among the nozzles 30 constituting the same nozzle row, the nozzles 30 located at both ends are ink in a recording operation (liquid ejecting operation) performed for recording an image or the like on a recording medium or the like. This is a non-injection nozzle 30b where no injection is performed. Regarding such a non-ejection nozzle 30b, for example, when a larger head unit is configured by combining a plurality of recording heads 10, the nozzles at the ends corresponding to the joints between the nozzle rows of adjacent recording heads are positioned in the nozzle row direction. Are provided so as to overlap each other, and one of the overlapping nozzles is a non-injection nozzle. In addition, when a liquid ejecting operation is performed on a recording medium or the like whose dimension (width) in the nozzle array direction is narrower than the entire length of the nozzle array, the nozzle located outside the recording area is a non-ejection nozzle. The

  In the printer 1 having the above-described configuration, when a large amount of ink is ejected from a large number of nozzles 30 (ejection nozzles 30a) among the nozzles 30 constituting the same nozzle row, specifically, the same nozzle row is arranged. When the total ink amount (maximum value) when each of the largest size ink droplets is ejected from all the constituent nozzles 30 is 100%, for example, when the operation of ejecting the ink amount with a high DUTY of 70% or more is performed, In some cases, pressure loss increases in the ink supply path, resulting in insufficient supply of ink to the reservoir 43. Particularly, in the configuration in which the flexible compliance sheet 44 is provided in the reservoir 43 as in the recording head 10 in the present embodiment, immediately after the high DUTY period in which ink is ejected at the high DUTY as described above. When the DUTY is lower than a certain value (for example, less than 30%) than this, a low DUTY period or a pause period (DUTY = 0%) where no ink is ejected from each nozzle 30 is provided, or such a low DUTY When a sudden change occurs in the ink ejection state (when DUTY changes rapidly), such as when a high DUTY period is provided immediately after the period or pause period, the above-described compliance sheet 44 is predetermined. May vibrate with a natural period of. That is, the pressure of the ink in the reservoir 43 periodically increases and decreases. When ink is ejected with a relatively high DUTY in a state where the pressure in the reservoir 43 is reduced by this vibration, the pressure loss increases in the ink supply path on the upstream side of the reservoir 43, so that the upstream side Insufficient supply of ink occurs because ink does not catch up with the reservoir 43. When such ink shortage occurs and ink ejection is continued, the ink in the reservoir 43 is depressurized as the ink is consumed from the ejection nozzle 30a, as shown in FIGS. As described above, ink is drawn from the non-ejecting nozzle 30b side where ink is not ejected. If the pulling force is large, air may be drawn from the non-ejecting nozzle 30b and enter the ink flow path. When air enters the ink flow path, the ink may not be ejected normally from the ejection nozzle 30a. Hereinafter, the above-described DUTY is used as an index representing the ink ejection status (liquid ejection status) in each nozzle 30. The ink ejection status can also be grasped by the flow velocity at a specific position in the ink supply path from the ink cartridge 8 to the reservoir 43.

  FIG. 8 and FIG. 9 are diagrams for explaining the conditions of the ejection situation in which insufficient ink supply occurs. FIG. 8 is a schematic diagram for explaining the change in the ink ejection situation for each nozzle 30, and FIG. It is a table | surface which shows the test result about the presence or absence of the countermeasure of an ink supply shortage about an ink ejection condition. In FIG. 8, hatched portions indicate a state where ink is ejected from the corresponding nozzle 30 (ejecting nozzle 30 a), and other portions indicate a state where ink is not ejected. Yes. In the example of FIG. 8, the nozzle row is composed of a total of 400 nozzles 30 from the nozzle 30 with the nozzle number # 1 to the nozzle 30 with the nozzle number # 400, of which the nozzle row is located at the end of the nozzle row. The nozzle 30 with nozzle number # 1 and the nozzle 30 with nozzle number # 400 are non-injection nozzles 30b, and the remaining nozzles 30 with nozzle numbers # 2 to # 399 are injection nozzles 30a. In the period A, ink droplets of the maximum size are ejected simultaneously from the ejection nozzles 30a with the nozzle numbers # 2 to # 399. In this case, the DUTY is 99.5%. The period B following the period A is a pause period in which DUTY is 0%, that is, no ink is ejected from any nozzle 30. A period C subsequent to the period B is a period in which ink is ejected at a duty ratio of 99.5% as in the period A. The non-ejecting nozzle 30b means a nozzle that is not constantly used for ejecting ink in the recording operation (liquid ejecting operation). The ejection nozzle 30a means a nozzle used for ejecting ink in a recording operation. The jet nozzle 30a may not be used in the recording operation depending on the content to be recorded (image or the like).

  Here, as shown in FIG. 9, if the time of the period B, which is a pause period or a low DUTY period, is less than 1.5 [ms], vibration in the ink in the reservoir 43 is hardly excited, and the countermeasure is It was unnecessary. Similarly, if the period B is 3 ms or longer, even if the ink in the reservoir 43 vibrates due to a change in DUTY between the period A and the period B, the vibration almost converges in the period B. As a result, no measures were required. When the time of period B is 1.5 [ms] or more and less than 3 [ms] and the time of period A is less than 1.5 [ms], the change in DUTY between period A and period B As a result, the ink in the reservoir 43 hardly vibrates and no countermeasure is required. Further, even if the time of period A is 1.5 [ms] or more, if the period of period C is less than 1.5 [ms], the reservoir is also changed by the change in DUTY between period A and period B. As a result, it was difficult for the ink in the ink 43 to vibrate, and no countermeasure was required. In the following, it is assumed that the time of period A and period C is 1.5 [ms] or more, and the time of period B is 1.5 [ms] or more and less than 3 [ms].

  When the DUTY in the period B is 30% or more, the difference in the DUTY between the period A and the period B and the difference in the DUTY between the period B and the period C are relatively small, so the ink in the reservoir 43 As a result, it was difficult for vibration to occur and no countermeasures were required. Even if the DUTY in period B is less than 30%, if the DUTY in period A and period C is less than 70% (the difference in DUTY between AB and BC is less than 40%), the DUTY in period A is 70% If DUTY in period C is 70% or more, or if UTYD in period A is 70% or more and DUTY in period C is less than 70%, a problem due to vibration of ink in reservoir 43 occurs. As a result, no measures were required.

  In contrast, when DUTY in period A and period C is 70% or more and DUTY in period B is 0%, or when ink is ejected in period B (low-duty ejection of less than 30%) ), For example, the difference in DUTY between period A and period B and between period B and period C, such as when DUTY in period A and period C is 99.5% When the difference in DUTY is 70% or more, there is a possibility that air may be drawn from the non-ejecting nozzle 30b into the ink flow path due to insufficient supply of ink due to the vibration of the ink in the reservoir 43. As a result, it was necessary.

  In the printer 1 according to the present invention, the ink in the non-ejecting nozzle 30b is satisfied when the ink ejection status of each nozzle 30 in the nozzle row satisfies the specific condition that induces the shortage of ink supply to the reservoir 43 as described above. By controlling the vibration of the (meniscus), air intake from the non-injection nozzle 30b is suppressed. Hereinafter, this point will be described.

  The change in DUTY can be recognized by the CPU 17 based on print data received from an external device or the like. In this embodiment, the difference in DUTY between the period A and the period B and the difference in DUTY between the period B and the period C are 70% or more, respectively. When the condition that the time of period B is 1.5 [ms] or more and less than 3 [ms] is satisfied for 1.5 [ms] or more, a countermeasure described later is performed. The conditions for executing the countermeasure are acquired in advance, for example, by performing a test at a stage before shipment as a product of the printer 1, and information about the conditions is stored in the storage device 18.

  Here, the ejection drive pulse Pd used for the ink ejection operation, and the vibration drive pulse used for the vibration operation (also referred to as the fine vibration operation) that vibrates the ink (meniscus) in order to suppress the ink thickening at the nozzle 30. And the vibration drive pulse for a countermeasure applied to the piezoelectric element 31 corresponding to the non-injection nozzle 30b when the said conditions are satisfy | filled is demonstrated.

  FIG. 10 is a waveform diagram of the ejection drive pulse Pd (a kind of first drive pulse in the present invention), and FIG. 11 is a waveform diagram of the first vibration drive pulse Pv1 (a kind of vibration drive pulse in the present invention). FIG. 12 is a waveform diagram of the second vibration drive pulse Pv2 for countermeasures (a kind of second drive pulse in the present invention).

  The injection drive pulse Pd shown in FIG. 10 includes an expansion element p1, an expansion hold element p2, a contraction element p3, a contraction hold element p4, and a return element p5. The expansion element p1 is a waveform element in which the potential drops from the reference potential Eb corresponding to the reference volume of the pressure chamber 33 (the volume serving as a reference for expansion or contraction) to the expansion potential EL1 lower than the reference potential Eb. The element p2 is a waveform element that maintains the expansion potential EL1 that is the terminal potential of the expansion element p1 for a predetermined time. The contraction element p3 is a waveform element that increases the potential with a steep slope from the expansion potential EL1 to the contraction potential EH1 higher than the reference potential Eb. The contraction hold element p4 is a waveform element that maintains the contraction potential EH1 for a certain period. The return element p5 is a waveform element that returns the potential from the contraction potential EH1 to the reference potential Eb to the extent that ink is not ejected.

  When the ejection drive pulse Pd is supplied to the piezoelectric element 31, first, the central portion in the width direction of the piezoelectric element 31 (and the operating portion of the diaphragm 36. The same applies hereinafter) is expanded outside the pressure chamber 33 by the expansion element p 1. It bends toward (the side away from the nozzle plate 24). As a result, the pressure chamber 33 expands from the reference volume corresponding to the reference potential Eb to the expansion volume corresponding to the expansion potential EL1. Due to this expansion, the ink in the pressure chamber 33 is depressurized, and the meniscus in the nozzle 30 (jet nozzle 30a) is drawn into the pressure chamber 33 side, and the ink enters the pressure chamber 33 through the individual communication port 35 from the reservoir 43 side. Supplied. The expanded state of the pressure chamber 33 is maintained over the supply period of the expansion hold element p2. Thereafter, the contraction element p <b> 3 is applied, so that the central portion of the piezoelectric element 31 bends inside the pressure chamber 33. Thereby, the pressure chamber 33 is rapidly contracted from the expansion volume to the contraction volume corresponding to the contraction potential EH1. The ink in the pressure chamber 33 is pressurized by the rapid contraction of the pressure chamber 33, and a specified amount of ink is ejected from the nozzle 30 (ejection nozzle 30a). The contraction state of the pressure chamber 33 is maintained over the supply period of the contraction hold element p4. During this period, the pressure vibration of the ink in the nozzle 30 caused by the ink ejection repeats increase and decrease periodically. Then, the return element p5 is supplied in accordance with the timing at which the ink pressure rises, and accordingly, the piezoelectric element 31 and the central portion of the operating portion are bent toward the outside of the pressure chamber 33 to return to the reference state.

  The first vibration drive pulse Pv1 shown in FIG. 11 has a vibration expansion element p11, a vibration expansion hold element p12, and a vibration contraction element p13. The vibration expansion element p11 is a waveform element that lowers the potential from the reference potential Eb to the first vibration expansion potential Ev1 that is lower than the reference potential Eb. The vibration expansion hold element p12 is a waveform element that maintains the first vibration expansion potential Ev1 that is the terminal potential of the vibration expansion element p11 for a certain period of time. The vibration contraction element p13 is a waveform element that gradually increases the potential from the first vibration expansion potential Ev1 to the reference potential Eb to such an extent that ink is not ejected from the nozzle 30. The potential difference between the reference potential Eb and the first vibration expansion potential Ev1 is the vibration voltage V1 of the first vibration drive pulse Pv1, and from the drive voltage Vd of the ejection drive pulse Pd (potential difference between the contraction potential EH1 and the expansion potential EL1). Is set small enough.

  When the first vibration drive pulse Pv <b> 1 configured in this way is supplied to the piezoelectric element 31, first, the central portion in the width direction of the piezoelectric element 31 is bent to the outside of the pressure chamber 33 by the vibration expansion element p <b> 11. As a result, the pressure chamber 33 expands from the reference volume corresponding to the reference potential Eb to the first vibration expansion volume corresponding to the first vibration expansion potential Ev1. Due to the expansion of the pressure chamber 33, the inside of the pressure chamber 33 is depressurized, and the meniscus in the nozzle 30 is drawn toward the pressure chamber 33 as shown by the hatched arrows in FIG. The expanded state of the pressure chamber 33 is maintained over the supply period of the vibration expansion hold element p12. Thereafter, when the vibration contraction element p13 is applied, the central portion of the piezoelectric element 31 bends inside the pressure chamber 33 and returns to the reference state. Thereby, the pressure chamber 33 returns to the reference volume. Along with the series of volume fluctuations of the pressure chamber 33, pressure vibration is generated in the pressure chamber 33 so that ink is not ejected from the nozzle 30, and the ink (meniscus) in the nozzle 30 vibrates due to this pressure vibration. The thickened ink in the vicinity of the nozzle 30 is diffused by the vibration of the meniscus, and as a result, the thickening of the ink can be suppressed.

  In a normal recording operation, a vibration operation is performed using the first vibration drive pulse Pv1 in order to suppress ink thickening in the non-ejection nozzle 30b. This oscillating operation is performed at a timing when ink is not ejected from the ejection nozzle 30a. Generally, in vibration operation, vibration driving is performed so that the meniscus is mainly drawn into the ink flow path side (pressure chamber 33 side or reservoir 43 side) so that ink is not accidentally ejected from the nozzles. The pulse is designed. However, when the supply of ink to the reservoir 43 is insufficient due to a rapid change in DUTY, as shown in FIG. 7, the ink is ejected from the ejection nozzle 30a, and the non-ejection nozzle 30b side If the timing at which the meniscus in the non-ejection nozzle 30b is drawn by the vibration expansion element p11 of the first vibration drive pulse Pv1 overlaps with the timing at which the ink is drawn from the reservoir 43 to the reservoir 43 side, more air is discharged from the non-ejection nozzle 30b. It becomes easy to be drawn.

  For this reason, in the printer 1 according to the present invention, when the ejection state at each nozzle 30 satisfies the above-described conditions, the second vibration drive pulse Pv2 for countermeasures replaces the first vibration drive pulse Pv1 with the non-ejection nozzle 30b. Vibration operation is performed. The switching between the first vibration drive pulse Pv1 and the second vibration drive pulse Pv2 is transmitted from the drive signal generation circuit 19 to the recording head 10 through different signal paths, and the recording head is satisfied in accordance with the establishment of the above conditions. 10 can be configured to be selectively applied to the piezoelectric element 31 by switching the signal path, or the waveform of the first vibration drive pulse Pv1 in the drive signal generation circuit 19 in accordance with the establishment of the above condition. May be changed to the waveform of the second vibration drive pulse Pv2 and transmitted to the shape recording head 10 side. Furthermore, as will be described later, a configuration in which a part of the waveform element of the ejection drive pulse Pd is selectively applied to the piezoelectric element 31 as the second vibration drive pulse Pv2 may be employed.

  Like the first vibration drive pulse Pv1, the second vibration drive pulse Pv2 shown in FIG. 12 includes a vibration expansion element p11, a vibration expansion hold element p12, and a vibration contraction element p13. Is different from the first vibration drive pulse Pv1 in that the point is increased and the timing of application to the piezoelectric element 31 is changed (described later). That is, the waveform of the vibration expansion element p11 in the second vibration drive pulse Pv2 lowers the potential from the reference potential Eb corresponding to the reference volume of the pressure chamber 33 to the second vibration expansion potential Ev2 lower than the first vibration expansion potential Ev1. Is an element. The vibration expansion hold element p12 in the second vibration drive pulse Pv2 is a waveform element that maintains the second vibration expansion potential Ev2 that is the terminal potential of the vibration expansion element p11 for a certain period of time. The vibration contraction element p13 in the second vibration drive pulse Pv2 is a waveform element that raises the potential from the second vibration expansion potential Ev2 to the reference potential Eb. The vibration voltage V2 (potential difference between the reference potential Eb and the second vibration expansion potential Ev2) of the second vibration drive pulse Pv2 is set higher than the vibration voltage V1 of the first vibration drive pulse Pv1. For this reason, the amplitude of the vibration generated in the ink in the nozzle 30 (non-ejecting nozzle 30b) is larger in the second vibration driving pulse Pv2.

  FIG. 13 shows the waveform (upper stage) of pressure vibration generated in the ink in the non-ejecting nozzle 30b when the piezoelectric element 31 is driven by the second vibration drive pulse Pv2, and the piezoelectric element 31 corresponding to the ejecting nozzle 30a is ejected. It is the figure which showed the timing (middle stage) when the drive pulse Pd is applied, and the timing (lower stage) when the second vibration drive pulse Pv2 is applied to the piezoelectric element 31 corresponding to the non-injection nozzle 30b. . In the upper part of the figure, the horizontal axis represents time, and the vertical axis represents the displacement of the meniscus (the central part of the meniscus) in the non-injection nozzle 30b. In this case, the initial position is a state in which the reference potential Eb is continuously applied to the piezoelectric element 31, and the meniscus (center portion of the meniscus) in a state where the meniscus is settled by the non-injection nozzle 30b. Position. In the middle and lower parts of the figure, the horizontal axis indicates time, and the vertical axis indicates voltage.

As shown in FIG. 13, when the piezoelectric element 31 is driven by the second vibration drive pulse Pv2, pressure vibration is generated in the ink in the non-ejection nozzle 30b, and this vibration cycle Tc is expressed by the following equation (1). be able to.
Tc = 2π√ {Cc / [(1 / Mn) + (1 / Ms)]} (1)
In equation (1), Mn is the inertance of the nozzle 30 (non-jet nozzle 30b) (mass of ink per unit cross-sectional area: [ink density ρ × channel length L] / channel cross-sectional area S), and Ms is individual. The inertance Cc of the communication port 35 is the compliance of the pressure chamber 33 (indicating the volume change per unit pressure and the degree of softness).

When ink is ejected by the contraction element p3 of the ejection drive pulse Pd on the ejection nozzle 30a side at the timing when the meniscus in the non-ejection nozzle 30b is displaced toward the pressure chamber 33 due to the pressure vibration, the non-ejection nozzle 30b. Air is easily drawn from. Therefore, ink is ejected by the contraction element p3 of the ejection drive pulse Pd on the ejection nozzle 30a side at the timing when the meniscus in the non-ejection nozzle 30b is displaced toward the ejection side (the recording medium side on the platen 3). In addition, the application timing of the second vibration drive pulse Pv2 (the generation timing relative to the ejection drive pulse Pd) is adjusted. More specifically, as shown in FIG. 13, regarding the time Δt from the end of the vibration expansion element p11 of the second vibration drive pulse Pv2 to the start of the contraction element p3 of the injection drive pulse Pd, the following equation (2) Or the application timing of the 2nd vibration drive pulse Pv2 is adjusted so that it may become a value within the range of Formula (3).
Tc / 4 ≦ Δt ≦ Tc / 2 (2)
5Tc / 4 ≦ Δt ≦ 3Tc / 2 (3)

  FIG. 14 is a schematic diagram illustrating the flow of ink between the ejection nozzle 30a and the non-ejection nozzle 30b when the vibration operation is performed by the second vibration drive pulse Pv2. The second vibration drive pulse Pv2 is applied to the piezoelectric element 31 corresponding to the non-injection nozzle 30b at a timing at which the time Δt falls within the range of the expression (2) or the expression (3), whereby the non-injection nozzle 30b. Ink is ejected on the ejection nozzle 30a side at the timing when the ink (meniscus) is displaced toward the ejection side. In other words, the vibration of the ink generated by the second vibration drive pulse Pv2 in the non-ejection nozzle 30b and the vibration of the ink generated by the ejection drive pulse Pd in the ejection nozzle 30a cancel each other as much as possible. Ink is ejected on the ejection nozzle 30a side so that the phase is reversed. For this reason, as shown in FIG. 14, even if a force to draw the ink toward the reservoir 43 acts on the ink on the non-ejecting nozzle 30b side as the ink is consumed from the ejecting nozzle 30a, the non-ejecting nozzle 30b Since the meniscus is moved to the injection side (see the hatched arrow in the figure), it resists the force to be drawn into the reservoir 43 side. For this reason, even if it is a case where the ejection condition in each nozzle 30 satisfy | fills the said conditions, it is suppressed that air is drawn in into an ink flow path from the non-ejecting nozzle 30b. As a result, even if the ink supply to the reservoir 43 is likely to be insufficient, such as when the ejection operation at high DUTY is repeated intermittently, air entrainment in the ink flow path is suppressed. However, it is possible to perform the ejection operation without taking measures to reduce the capability of the printer 1 such as lowering the DUTY or separately providing a standby time for converging the vibration in the reservoir 43. Become. In addition, since the vibration voltage of the second vibration drive pulse Pv2 in this embodiment is higher than that of the normal first vibration drive pulse Pv1, the amplitude of the pressure vibration generated in the ink in the non-ejecting nozzle 30b is further increased. be able to. As a result, air entrainment in the ink flow path can be more reliably suppressed.

15 to 18 are waveform diagrams for explaining modifications of the second vibration drive pulse Pv2. In addition, the waveform shown with the broken line in each figure has shown the 1st vibration drive pulse Pv1.
The second vibration drive pulse Pv2 is a drive pulse in which the vibration voltage V2 is higher than the vibration voltage V1 of the first vibration drive pulse Pv1, whereas the second vibration drive pulse Pv2a shown in FIG. The vibration voltage remains at V1, and the potential change rate (ratio of potential change with respect to time change) between the vibration expansion element p11 and the vibration contraction element p13 is steeper than in the case of the first vibration drive pulse Pv1. Is different. In this way, by making the potential change rate of the vibration expansion element p11 and the vibration contraction element p13 whose potential changes among the waveform elements of the second vibration drive pulse Pv2a more steep, the pressure vibration generated in the ink in the non-ejection nozzle 30b. Can be made larger in amplitude. Therefore, by adopting the second vibration drive pulse Pv2a instead of the second vibration drive pulse Pv2, the air is suppressed from being drawn into the ink flow path from the non-ejecting nozzle 30b. The application timing of the second vibration drive pulse Pv2a is the same as that of the second vibration drive pulse Pv2.

  The potential change rates of the vibration expansion element p11 and the vibration contraction element p13 can be set differently. For example, in the second vibration drive pulse Pv2b shown in FIG. 16, the potential change rate of the vibration expansion element p11 is set to be smaller than the potential change rate of the dynamic expansion element p11 of the first vibration drive pulse Pv1. The potential change rate of the contraction element p13 is set larger than the potential change rate of the vibration contraction element p13 of the first vibration drive pulse Pv1. For this reason, in the second vibration drive pulse Pv2b, the force for contracting the pressure chamber 33 to pressurize the ink is larger than the force for expanding and depressurizing the pressure chamber 33. That is, the second vibration drive pulse Pv2b is a drive pulse that pressurizes the ink in the non-ejection nozzle 30b by time average by driving the piezoelectric element 31. For this reason, according to the second vibration drive pulse Pv2b, the force that pushes the ink toward the ejection side in the non-ejecting nozzle 30b is large, so that air is more effectively suppressed from being drawn into the ink flow path from the non-ejecting nozzle 30b. Is done. The application timing of the second vibration drive pulse Pv2b is the same as that of the second vibration drive pulse Pv2.

  In the second vibration drive pulse Pv2c shown in FIG. 17, the vibration voltage V2 is higher than the vibration voltage V1 of the first vibration drive pulse Pv1, and the potential change rate between the vibration expansion element p11 and the vibration contraction element p13 is the first. It is steeper than in the case of one vibration drive pulse Pv1. Thereby, the amplitude of the pressure vibration generated in the ink in the non-ejecting nozzle 30b can be further increased. Therefore, by adopting the second vibration drive pulse Pv2c instead of the second vibration drive pulse Pv2, it is possible to further reliably suppress the air from being drawn into the ink flow path from the non-ejecting nozzle 30b. The application timing of the second vibration drive pulse Pv2c to the piezoelectric element 31 is the same as that of the second vibration drive pulse Pv2.

  The second vibration drive pulse Pv2d shown in FIG. 18 differs from the above-described second vibration drive pulses Pv2, Pv2a, Pv2b, and Pv2c in the direction of potential change from the reference potential Eb. Specifically, the second vibration drive pulse Pv2d has a vibration contraction element p21, a vibration contraction hold element p22, and a vibration expansion element p23. The vibration contraction element p21 is a waveform element that increases the potential from the reference potential Eb to the vibration contraction potential Ev3 that is higher than the reference potential Eb. The vibration contraction hold element p22 is a waveform element that maintains the vibration contraction potential Ev3, which is the terminal potential of the vibration contraction element p21, for a predetermined time. The vibration expansion element p23 is a waveform element that lowers the potential from the vibration contraction potential Ev3 to the reference potential Eb. The vibration voltage V3 (potential difference between the vibration contraction potential Ev3 and the reference potential Eb) of the second vibration drive pulse Pv2 is set to a value equal to or greater than V1. That is, the second vibration drive pulse Pv2d contracts the pressure chamber 33 from the reference state and pushes the ink in the non-ejecting nozzle 30b to the ejection side, and then expands the pressure chamber 33 to return to the reference state to thereby reference the ink. It has a waveform for driving the piezoelectric element 31 to return to the position side. Even when the second vibration drive pulse Pv2d is employed instead of the second vibration drive pulse Pv2, the ink vibration generated by the second vibration drive pulse Pv2d in the non-ejecting nozzle 30b and the ejection drive in the ejection nozzle 30a are performed. The application timing of the second vibration drive pulse Pv2d to the piezoelectric element 31 corresponding to the non-ejecting nozzle 30b is adjusted so that the vibration of the ink generated by the pulse Pd has an opposite phase. Also with this configuration, the force that pushes the ink toward the ejection side acts on the non-ejecting nozzle 30b, so that air is more effectively suppressed from being drawn into the ink flow path from the non-ejecting nozzle 30b. Air is prevented from being drawn into the ink flow path from the non-ejecting nozzle 30b.

  For each of the second vibration drive pulses Pv2, Pv2a, Pv2b, Pv2c, and Pv2d, the configuration provided separately from the injection drive pulse Pd is illustrated. However, the configuration is not limited thereto, and one of the waveform elements of the injection drive pulse Pd is illustrated. It is also possible to adopt a configuration in which the part is selectively applied to the piezoelectric element 31 as the second vibration drive pulse Pv2. That is, in the ejection drive pulse Pd shown in FIG. 10, the contraction element p3 is the first contraction element p3a on the minus side (expansion potential EL1 side) and the plus side (contraction potential EH1 side) from the reference potential Eb. And the second contraction element p3b. Of these, the second contraction element p3b, the contraction hold element p4, and the return element p5 are selected and applied to the piezoelectric element 31 corresponding to the non-injection nozzle 30b as the second vibration drive pulse Pv2 for countermeasures. Can also be adopted. Also in this configuration, ink is ejected on the ejection nozzle 30a side at the timing when the meniscus in the non-ejection nozzle 30b is displaced toward the ejection side by the second vibration drive pulse Pv2. In other words, the vibration of the ink generated by the second vibration drive pulse Pv2 in the non-ejection nozzle 30b and the vibration of the ink generated by the ejection drive pulse Pd in the ejection nozzle 30a cancel each other as much as possible. Since ink is ejected on the ejection nozzle 30a side so that the phase is reversed, air is suppressed from being drawn into the ink flow path from the non-ejection nozzle 30b. Further, according to this configuration, since it is not necessary to separately provide the second vibration drive pulse, the configuration and signal path of the drive signal generation circuit 19 can be further simplified.

  Regarding the vibration voltage of these second vibration drive pulses, the voltage can be set to a level at which ink is normally ejected (in a state where the above conditions are not satisfied). Thereby, the amplitude of the vibration of the ink generated by the second vibration drive pulse in the non-ejecting nozzle 30b becomes larger, and the air is more effectively suppressed from being drawn into the ink flow path.

  In each of the above-described embodiments, the so-called flexural vibration type piezoelectric element 31 is exemplified as the drive element. However, the present invention is not limited to this, and for example, a so-called longitudinal vibration type piezoelectric element can be employed. In this case, with respect to each of the exemplified driving pulses, the waveform changes in the potential change direction, that is, up and down (polarity). In addition, the actuator is not limited to the piezoelectric element, and other driving elements such as an electrostatic actuator may be employed.

  In the above description, the ink jet recording head 10 (recording head 10), which is a kind of liquid ejecting head, has been described as an example. However, the present invention is also applicable to other liquid ejecting heads and liquid ejecting apparatuses including the same. can do. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to a liquid ejecting head including a plurality of bio-organic matter ejecting heads and the like and a liquid ejecting apparatus including the same.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Frame, 3 ... Platen, 4 ... Conveyance mechanism, 5 ... Guide rod, 6 ... Carriage, 7 ... Carriage moving mechanism, 8 ... Ink cartridge, 10 ... Recording head, 11 ... Wiping mechanism, 12 ... Wiper 13 ... Capping mechanism 13 ... Cap, 15 ... Draining tube, 16 ... Pump unit, 17 ... CPU, 18 ... Storage device, 19 ... Drive signal generation circuit, 20 ... Input / output interface, 23 ... Fixing plate, 24 ... Nozzle Plate, 25 ... Communication plate, 26 ... Actuator substrate, 27 ... Compliance substrate, 28 ... Holder, 29 ... Pressure chamber forming substrate, 30 ... Nozzle, 31 ... Piezoelectric element, 32 ... Protection substrate, 33 ... Pressure chamber, 34 ... Nozzle Communication port, 35 ... Individual communication port, 36 ... Diaphragm, 38 ... Drive IC, 39 ... Flexible substrate, 40 ... Wiring , 41 ... accommodating space, 43 ... reservoir, 44 ... compliance sheet, 45 ... support plate, 46 ... through opening, 47 ... compliance space, 48 ... compliance opening, 49 ... accommodating cavity, 50 ... inserting cavity, 51 ... Liquid chamber empty space, 52 ... Inlet

Claims (6)

A plurality of nozzle groups each composed of a plurality of nozzles, a plurality of nozzles corresponding to each nozzle, a drive element that generates pressure vibrations in the liquid in the corresponding nozzle, and a common liquid supplied to each nozzle are supplied A liquid ejecting head having a liquid chamber;
A drive pulse generation circuit for generating a drive pulse for driving the drive element;
A liquid ejecting apparatus comprising:
The nozzle group includes a first nozzle and a second nozzle,
The drive pulse generation circuit generates a first drive pulse and a second drive pulse,
The first driving pulse is a driving pulse that is applied to the driving element corresponding to the first nozzle and ejects liquid from the first nozzle,
The second drive pulse corresponds to the second nozzle when the liquid ejection state of each nozzle in the nozzle group satisfies a specific condition that induces insufficient supply of liquid to the common liquid chamber. A liquid ejecting apparatus, wherein the liquid ejecting apparatus is a driving pulse that is applied to a driving element to cause pressure oscillation in the liquid in the second nozzle. The drive pulse generation circuit is capable of generating a vibration drive pulse that is applied to the drive element corresponding to the nozzle that is not ejected of liquid and causes pressure vibration in the liquid in the nozzle,
2. The liquid ejecting apparatus according to claim 1, wherein the second driving pulse is a driving pulse that generates a larger pressure vibration in the liquid in the nozzle than in the case of the vibration driving pulse.   The liquid ejection according to claim 2, wherein the second drive pulse is a drive pulse for driving the drive element so as to increase the pressure of the liquid in the second nozzle and push the liquid toward the ejection side. apparatus.   3. The pressure vibration of the liquid in the second nozzle caused by the second drive pulse is opposite in phase to the pressure vibration caused by the ejection of the liquid in the first nozzle. Alternatively, the liquid ejecting apparatus according to claim 3.   The liquid ejecting apparatus according to claim 1, wherein a part of the common liquid chamber is partitioned by a compliance member having flexibility. A plurality of nozzle groups each composed of a plurality of nozzles, a plurality of nozzles corresponding to each nozzle, a drive element that generates pressure vibrations in the liquid in the corresponding nozzle, and a common liquid supplied to each nozzle are supplied A control method of a liquid ejecting apparatus comprising: a liquid ejecting head having a liquid chamber; and a drive pulse generating circuit that generates a drive pulse for driving the drive element,
While applying the first drive pulse to the drive element corresponding to the first nozzle when ejecting liquid from the first nozzle of the nozzles constituting the nozzle group,
When the liquid ejection state of each nozzle in the nozzle group satisfies a specific condition that induces insufficient supply of liquid to the common liquid chamber, the second nozzle among the nozzles constituting the nozzle group A control method for a liquid ejecting apparatus, wherein a second driving pulse is applied to the corresponding driving element to cause pressure oscillation in the liquid in the second nozzle.

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