JP2018094799A - Liquid jet head, liquid jet recording device and liquid jet head driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To be able to suppress influences of crosstalk easily without complicating a configuration of a device.SOLUTION: A liquid jet head comprises: a plurality of nozzles for jetting liquid; a piezoelectric actuator that has a plurality of pressure chambers which correspond to the plurality of nozzles respectively and are filled with liquid, and varies volumes in the pressure chambers; and a control part that inflates and deflates the volumes in the pressure chambers by applying pulse signals to the piezoelectric actuator so as to jet the liquid filled into the pressure chambers, and varies discharge amounts of liquid droplets in a plurality of gradation by a plurality of kinds of driving waveforms in which one of more inflating pulse signals for inflating the volumes in the pressure chambers are overlapped in plural numbers. The control part generates a first driving waveform and a second driving waveform which can discharge the droplets more than the first driving waveform to different pressure chambers, and applies deflating pulse signals for deflating the volumes in the pressure chambers at least after generating the second driving waveform lastly.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a liquid jet head, a liquid jet recording apparatus, and a liquid jet head driving method.

  A liquid jet recording apparatus provided with a liquid jet head is used in various fields. In recent years, demands for higher printing speeds have increased, and liquid ejecting heads have increased numbers of nozzles and nozzle arrays, heads capable of ejecting liquid droplets at high frequencies, and large liquids with larger droplet sizes. Heads that can eject droplets have been commercialized. In addition, since high image quality is also required, the liquid ejecting head covers small to large droplets by increasing the gradation of the droplet size and discharging the droplet size in multiple gradations. Has also been developed.

  Since both high definition and high productivity as described above are required, the influence of crosstalk, which is a problem with liquid ejecting heads, tends to be more noticeable than with conventional liquid ejecting heads, resulting in poor drawing image quality. Is caused. Crosstalk in the liquid ejecting head occurs because a difference occurs in the presence / absence of vibration after-effects depending on the discharge state in the vicinity of the nozzle in the vicinity of the nozzle that ejects droplets. This also occurs because the meniscus state at each nozzle opening differs depending on the discharge amount of the entire head.

  As a technique for suppressing the adverse effect on image quality due to crosstalk, it is a common practice to optimize the discharge conditions of each nozzle. In many cases, a predetermined test pattern is drawn by a printing apparatus, the drawing data is read and fed back to the apparatus, and an optimum discharge condition is set.

  Further, Patent Document 1 stores a history of the discharge status of each nozzle, and a technique for suppressing the influence of crosstalk by applying an optimal discharge drive waveform to each nozzle according to the history. Have been described. Japanese Patent Application Laid-Open No. 2004-228561 describes a technique for suppressing the influence of crosstalk by delaying the application timing of the ejection drive waveform in accordance with the nozzle row and the ejection droplet size of each nozzle.

JP 2009-241345 A JP 2005-238728 A

  However, in the method of drawing a test pattern, it is necessary to add a function for reading and analyzing drawing data to the recording apparatus itself, which often results in a complicated apparatus configuration. Further, in a liquid jet recording apparatus that is digital printing, there are various image data to be printed, so the optimum condition derived from a predetermined test pattern is not always the optimum condition for actual printing. Since the injection state of each nozzle changes variously, it is difficult to carry out adjustment for suppressing crosstalk each time. Further, in the technique described in Patent Document 1, it is possible to provide an optimum drive waveform corresponding to each nozzle, but it is necessary to have means for storing the discharge status and means for selecting the optimum drive waveform. There is a problem that the control on the apparatus side becomes complicated. In the technique described in Patent Document 2, the influence of crosstalk is suppressed by slightly shifting the discharge timing of each nozzle. However, in order to meet the recent high productivity, the drive waveform is set at a high frequency. In this case, the effect of shifting the timing is reduced. In such a background, a liquid jet recording apparatus is required to have a technique for easily overcoming problems such as crosstalk peculiar to the liquid jet head in order to achieve higher definition image quality.

  Accordingly, the present invention has been made in view of the above-described circumstances, and a liquid jet head, a liquid jet recording apparatus, and a liquid jet that can easily suppress the influence of crosstalk without complicating the apparatus configuration. It is an object to provide a head driving method.

  One aspect of the present invention includes a plurality of nozzles for ejecting liquid, a plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with liquid, and a piezoelectric actuator for changing a volume in the pressure chamber; By applying a pulse signal to the piezoelectric actuator, the volume in the pressure chamber is expanded and contracted, the liquid filled in the pressure chamber is ejected, and an expansion pulse signal for expanding the volume in the pressure chamber is generated. And a control unit that varies the discharge amount of the droplets by a plurality of gradations using one or a plurality of types of driving waveforms that are overlapped, and the control unit is based on the first driving waveform and the first driving waveform. A contraction pulse signal for generating a second drive waveform having a large discharge amount for the pressure chamber different from the first, and contracting the volume in the pressure chamber at least at the end of the second drive waveform. Applying a liquid jet head, characterized by.

  According to another aspect of the present invention, in the liquid ejecting head, the control unit determines the final expansion pulse signal of the second drive waveform from the final expansion pulse signal of the first drive waveform. It is characterized by being applied as soon as possible.

  Further, according to one embodiment of the present invention, in the liquid ejecting head, the plurality of nozzles are arranged in a plurality of rows on a plane, and the control unit ejects liquid from nozzles of an arbitrary nozzle row. The pulse signal is applied so that the discharge timing to be delayed is later than the discharge timing of the nozzles of the adjacent nozzle row.

  According to another aspect of the present invention, in the liquid ejecting head, the control unit applies a plurality of the contraction pulse signals in succession.

  According to another aspect of the present invention, in the liquid ejecting head, the control unit sets the final expansion pulse signal of the second drive waveform in a range from 0.1 μs to 5.0 μs. Applying earlier than the final expansion pulse signal of one drive waveform.

  In addition, according to one embodiment of the present invention, in the liquid ejecting head, the time for delaying the ejection timing is in a range from 0.1 μs to 20 μs.

  Further, according to one embodiment of the present invention, in the liquid ejecting head, there is one inflow path in which the liquid is filled in each nozzle row in which the plurality of nozzles are arranged, and the one inflow Each nozzle row is filled with liquid in a form branched from the path.

  One embodiment of the present invention is characterized in that, in the liquid ejecting head, a maximum droplet discharge amount of one droplet is 70 pl or more with respect to the discharge amount.

  One embodiment of the present invention is characterized in that, in the liquid ejecting head, the liquid ejecting head is a circulating liquid ejecting head capable of ejecting droplets while circulating the liquid.

  One embodiment of the present invention is characterized in that, in the liquid ejecting head, a viscosity value of the ejected liquid at 25 ° C. is in a range from 10 mPa · s to 40 mPa · s.

  Another embodiment of the present invention is a liquid jet recording apparatus including the liquid jet head.

  According to another aspect of the invention, the liquid jet recording apparatus is a line type liquid jet recording apparatus that performs recording in a form in which the liquid jet head is fixed to the liquid jet recording apparatus.

  According to another aspect of the present invention, there is provided a piezoelectric actuator that includes a plurality of nozzles that eject liquid and a plurality of pressure chambers that correspond to the plurality of nozzles and that are filled with liquid, and that changes a volume in the pressure chamber. And by applying a pulse signal to the piezoelectric actuator, the volume in the pressure chamber is expanded and contracted, the liquid filled in the pressure chamber is ejected, and the volume in the pressure chamber is expanded. A liquid ejecting head driving method in a liquid ejecting head, comprising: a control unit that varies a discharge amount of droplets by a plurality of gradations by using one or a plurality of types of driving waveforms that overlap one another. Generating a first drive waveform and a second drive waveform having a discharge amount larger than that of the first drive waveform for different pressure chambers; At the end of at least the second drive waveform, which is a liquid ejection head driving method characterized by comprising the steps of: applying a decreasing pulse signal for contracting the pressure chamber volume.

  According to the present invention, the influence of crosstalk can be easily suppressed without complicating the apparatus configuration.

1 is a perspective view showing a configuration of a liquid jet recording apparatus in an embodiment of the present invention. FIG. 2 is a schematic partial exploded perspective view of a liquid jet head according to an embodiment of the present invention. FIG. 6 is an explanatory diagram of a liquid ejecting head according to an embodiment of the invention. It is a schematic block diagram which shows an example of the control part in embodiment of this invention. It is a figure which shows an example of the conventional drive waveform. It is a figure which shows an example of the drive waveform which the control circuit in embodiment of this invention outputs. It is a figure which shows an example of the drive waveform which the control circuit in embodiment of this invention outputs. It is a figure which shows an example of the drive waveform which the control circuit in embodiment of this invention outputs. It is a figure which shows an example of the printing image in embodiment of this invention. It is a figure which shows an example of the printing image in embodiment of this invention. It is a table | surface which shows measurement result (DELTA) E in each implementation condition in embodiment of this invention.

(Liquid jet recording device)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of the liquid jet recording apparatus 30 according to the present embodiment will be described.
FIG. 1 is a perspective view showing the configuration of the liquid jet recording apparatus 30. In the following drawings, the scale of each member is appropriately changed for easy explanation.

  As shown in the figure, the liquid jet recording apparatus 30 includes a moving mechanism 40 that reciprocates the liquid jet head 1, and a flow path unit 35 that supplies liquid to the liquid jet head 1 and discharges liquid from the liquid jet head 1. And a liquid pump 33 and a liquid tank 34 communicating with the flow path portion 35. Each liquid ejecting head 1 includes a plurality of groove rows, and an end portion on the other side of the ejection grooves included in the groove row on one side and an end portion on the one side of the non-ejection grooves included in the groove row on the other side. They are separated and overlap in the thickness direction of the piezoelectric substrate.

  The liquid jet recording apparatus 30 includes a pair of transport units 41 and 42 that transport a recording medium 44 such as paper in the main scanning direction, a liquid jet head 1 that discharges liquid onto the recording medium 44, and the liquid jet head 1. The carriage unit 43 to be placed, the liquid pump 33 that presses and supplies the liquid stored in the liquid tank 34 to the flow path portion 35, and the moving mechanism that scans the liquid ejecting head 1 in the sub-scanning direction orthogonal to the main scanning direction. 40. A control unit (not shown) controls and drives the liquid ejecting head 1, the moving mechanism 40, and the conveying units 41 and 42.

  The pair of conveying means 41 and 42 includes a grid roller and a pinch roller that extend in the sub-scanning direction and rotate while contacting the roller surface. A grid roller and a pinch roller are moved around the axis by a motor (not shown), and the recording medium 44 sandwiched between the rollers is conveyed in the main scanning direction. The moving mechanism 40 couples a pair of guide rails 36 and 37 extending in the sub-scanning direction, a carriage unit 43 slidable along the pair of guide rails 36 and 37, and the carriage unit 43 to move in the sub-scanning direction. An endless belt 38 is provided, and a motor 39 that rotates the endless belt 38 via a pulley (not shown) is provided.

  The carriage unit 43 mounts a plurality of liquid ejecting heads 1 and ejects, for example, four types of liquid droplets of yellow, magenta, cyan, and black. The liquid tank 34 stores the liquid of the corresponding color and supplies it to the liquid jet head 1 via the liquid pump 33 and the flow path portion 35. Each liquid ejecting head 1 ejects droplets of each color according to the drive signal. An arbitrary pattern can be recorded on the recording medium 44 by controlling the timing of discharging the liquid from the liquid ejecting head 1, the rotation of the motor 39 that drives the carriage unit 43, and the conveyance speed of the recording medium 44.

  In this embodiment, the moving mechanism 40 is a liquid jet recording apparatus 30 that moves the carriage unit 43 and the recording medium 44 for recording. Instead, the carriage unit is fixed and the moving mechanism is recorded. It may be a liquid jet recording apparatus that records by moving a medium two-dimensionally. That is, the moving mechanism may be any mechanism that relatively moves the liquid ejecting head 1 and the recording medium.

(Liquid jet head)
Next, the liquid jet head 1 will be described in detail.
FIG. 2 is a schematic partial exploded perspective view of the liquid ejecting head 1. FIG. 3 is an explanatory diagram of the liquid ejecting head 1. 3A is a schematic cross-sectional view of the ejection groove 3 in the groove direction, and FIG. 3B is a schematic plan view of the piezoelectric substrate 2 viewed from the lower surface LS side. The flexible circuit board 8 and the flow path plate 11 are shown in FIG. Is omitted.

  The liquid jet head 1 includes a piezoelectric substrate 2, a cover plate 9 bonded to the upper surface US of the piezoelectric substrate 2, a nozzle plate 13 bonded to the lower surface LS of the piezoelectric substrate 2, and the lower surface of the piezoelectric substrate 2. Flexible circuit boards 8x and 8y connected to the LS. The piezoelectric substrate 2 has ejection grooves 3 arranged in the reference direction K, and non-ejection grooves 4 penetrating from the upper surface US to the lower surface LS and alternately arranged in the reference direction K. The ejection grooves 3 and the non-ejection grooves 4 that are alternately arranged in the reference direction K constitute four groove rows 5 that are parallel to the first groove row 5a to the fourth groove row 5d. The piezoelectric substrate 2 further includes a drive electrode 6 installed on the side surfaces of the ejection groove 3 and the non-ejection groove 4, a terminal electrode 7 electrically connected to the drive electrode 6 and installed on the lower surface LS, and a second groove. A first opening H1 penetrating from the upper surface US to the lower surface LS is provided between the row 5b and the third groove row 5c. The flexible circuit board 8x is drawn from the lower surface LS of the piezoelectric substrate 2 to the upper surface US through the first opening H1.

  The cover plate 9 includes a liquid chamber 10 communicating with the ejection groove 3 and a second opening H2 penetrating in the thickness direction. The flexible circuit board 8x includes the first opening H1 and the second opening H2. Is drawn upward through. The nozzle plate 13 has nozzles 14 communicating with the respective ejection grooves 3, and four nozzles of the first nozzle row 15 a to the fourth nozzle row 15 d corresponding to the first groove row 5 a to the fourth groove row 5 d, respectively. Column 15 is configured.

  This will be specifically described. As shown in FIG. 3A, the ejection groove 3 penetrating from the upper surface US to the lower surface LS of the piezoelectric substrate 2 has a convex shape from the upper surface US to the lower surface LS, and the non-ejection groove 4 is from the lower surface LS to the upper surface US. Convex shape. Here, the discharge groove 3 and the non-discharge groove 4 included in the first groove row 5a are referred to as the first discharge groove 3a and the first non-discharge groove 4a, and the discharge groove 3 and the non-discharge groove 4 included in the second groove row 5b. Are the second ejection grooves 3b and the second non-ejection grooves 4b, and the ejection grooves 3 and the non-ejection grooves 4 included in the third groove row 5c are the third ejection grooves 3c and the third non-ejection grooves 4c. The ejection grooves 3 and the non-ejection grooves 4 included in 5d are referred to as a fourth ejection groove 3d and a fourth non-ejection groove 4d.

  In adjacent first groove row 5a and second groove row 5b, the end portion on the second groove row 5b side of the first discharge groove 3a included in the first groove row 5a on one side and the second groove row on the other side. The second non-ejection grooves 4 b included in 5 b are separated from the end portion on the first groove row 5 a side and overlap in the thickness direction of the piezoelectric substrate 2. Further, one end portion of the first non-ejection groove 4 a included in the first groove row 5 a is a shallow groove and is formed straight up to the one side surface of the piezoelectric substrate 2. The other end portion of the second non-ejection groove 4b included in the second groove row 5b is a shallow groove and is formed straight up to the side surface of the first opening H1. Each shallow groove has a depth from the lower surface LS deeper than ½ of the thickness of the piezoelectric substrate 2.

  Similarly, in the adjacent third groove row 5c and fourth groove row 5d, the end portion on the fourth groove row 5d side of the third discharge groove 3c included in the third groove row 5c on one side and the second groove row 5c on the other side. The fourth non-ejection groove 4d included in the four groove array 5d is separated from the end portion on the third groove array 5c side and overlaps in the thickness direction of the piezoelectric substrate 2. Further, one end of the third non-ejection groove 4c included in the third groove row 5c is a shallow groove and is formed straight up to the side surface of the first opening H1. The other end portion of the fourth non-ejection groove 4d included in the fourth groove row 5d is a shallow groove and is formed straight up to the other side surface of the piezoelectric substrate 2. Each shallow groove has a depth from the lower surface LS deeper than ½ of the thickness of the piezoelectric substrate 2. By forming the ejection grooves 3 and the non-ejection grooves 4 in this manner, the width in the groove direction of the first groove row 5a and the second groove row 5b and the groove direction of the third groove row 5c and the fourth groove row 5d are formed. The width can be shortened. Further, by forming one end of the non-ejection groove 4 as a shallow groove, a drive electrode (not shown) formed on both side surfaces of each non-ejection groove 4 is electrically separated and connected to the terminal electrode 7. Can do.

  The first ejection grooves 3a included in the first groove row 5a are arranged at a pitch P in the reference direction K. The second to fourth ejection grooves 3b to 3d included in the second to fourth groove rows 5b to 5d are also arranged at the pitch P in the reference direction K, respectively. The first ejection groove 3a and the second ejection groove 3b are shifted by 1/2 pitch P in the reference direction K. Similarly, the third ejection groove 3c and the fourth ejection groove 3d are shifted by ½ pitch P in the reference direction K. Further, the second ejection groove 3b and the third ejection groove 3c are shifted by a quarter pitch P in the reference direction K. As a result, the first to fourth ejection grooves 3 a to 3 d are arranged at a quarter pitch P in the reference direction K, and the recording density can be quadrupled compared to the case of one groove row 5.

  The structure of the drive electrode 6 and the terminal electrode 7 is demonstrated using FIG.3 (b). On the lower surface LS of the piezoelectric substrate 2, the discharge grooves 3 having a short length in the groove direction and the non-discharge grooves 4 having a long length in the groove direction are alternately arranged in the reference direction K, and the first to fourth groove rows 5a. ˜5d. A first opening H1 is opened at the center of the width of the piezoelectric substrate 2 in the groove direction. One end of both ends of the non-ejection groove 4 in the groove direction is a straight shallow groove, and the first non-ejection groove 4a of the first groove row 5a extends to the side surface of the piezoelectric substrate 2, The second non-ejection groove 4b of the two-groove row 5b extends to the side surface of the first opening H1. The third and fourth non-ejection grooves 4c and 4d of the third and fourth groove rows 5c and 5d have the same structure. Drive electrodes are provided on the side surfaces of the ejection grooves 3 and the non-ejection grooves 4. The drive electrode is installed so that the depth from the lower surface LS of each groove is approximately ½ of the thickness of the piezoelectric substrate 2.

  With respect to the first groove row 5 a, the terminal electrode 7 is installed on the lower surface LS near the side surface of the piezoelectric substrate 2. The terminal electrode 7 includes a common terminal electrode 7x that is electrically connected to drive electrodes on both sides of the first ejection groove 3a, and drive electrodes on both sides of the two first non-ejection grooves 4a that sandwich the first ejection groove 3a. And individual terminal electrodes 7y that are electrically connected. The individual terminal electrode 7y is installed on the side surface side of the piezoelectric substrate 2, the common terminal electrode 7x is installed on the first ejection groove 3a side with respect to the individual terminal electrode 7y, and both are regions to which the flexible circuit board 8y is connected. Exposed to. Regarding the second groove row 5b, the terminal electrode 7 includes a common terminal electrode 7x that is electrically connected to the drive electrodes 6 on both sides of the second discharge groove 3b, and two second non-discharge grooves that sandwich the second discharge groove 3b. 4b includes an individual terminal electrode 7y electrically connected to the driving electrode on the side surface of the first opening H1. The individual terminal electrode 7y is installed on the opening side of the first opening H1, the common terminal electrode 7x is installed on the second ejection groove 3b side with respect to the individual terminal electrode 7y, and both are connected to the flexible circuit board 8x. Exposed to the area. The third groove row 5c and the fourth groove row 5d have the same configuration.

  Then, the flexible circuit board 8y is connected to the region of the terminal electrode 7 (common terminal electrode 7x and individual terminal electrode 7y) of the first groove row 5a by thermocompression bonding, and the wiring pattern of the flexible circuit board 8y and the terminal electrode 7 are electrically connected. Connect. Further, the flexible circuit board 8x is connected by thermocompression bonding to the region of the terminal electrode 7 of the second groove row 5b through the second opening H2 and the first opening H1, and a wiring pattern and terminals (not shown) of the flexible circuit board 8x are connected. The electrode 7 is electrically connected. Similarly, for the third groove row 5c and the fourth groove row 5d, the flexible circuit boards 8x and 8y are connected to the lower surface LS, and the terminal electrode 7 and the wiring pattern are electrically connected.

  The cover plate 9 includes a second opening H2 formed at the center of the width in the groove direction, first to fourth liquid chambers 10a to 10d, and first and second common liquid chambers 10e and 10f. The first common liquid chamber 10e includes an end portion on the second groove row 5b side of the first discharge groove 3a included in the first groove row 5a and a first groove of the second discharge groove 3b included in the second groove row 5b. The first liquid chamber 10a communicates with the other end of the first discharge groove 3a, and the second liquid chamber 10b communicates with the other end of the second discharge groove 3b. Similarly, the second common liquid chamber 10f includes an end portion on the fourth groove row 5d side of the third discharge groove 3c included in the third groove row 5c and a fourth discharge groove 3d included in the fourth groove row 5d. The third liquid chamber 10c communicates with the other end of the third discharge groove 3c, and the fourth liquid chamber 10d communicates with the other end of the fourth discharge groove 3d. Communicate. The non-ejection groove 4 does not open on the upper surface US of the piezoelectric substrate 2 where each liquid chamber 10 opens. Therefore, it is not necessary to provide each liquid chamber 10 with a slit that communicates with the ejection groove 3 and closes the non-ejection groove 4. Thereby, the structure of the liquid chamber 10 becomes very simple. It is also possible to circulate the liquid by flowing the liquid into the first and second common liquid chambers 10e, 10f and outflowing the liquid from the first to fourth liquid chambers 10a-10d. Conversely, it can be circulated. Alternatively, the liquid may be supplied to all the liquid chambers 10.

  The flow path plate 11 is bonded to the surface of the cover plate 9 opposite to the piezoelectric substrate 2. The flow path plate 11 includes a supply flow path 12x, a discharge flow path 12y, and a third opening H3. The third opening H3 penetrates in the plate thickness direction of the flow path plate 11, and the flexible circuit board 8x is drawn upward through the third opening H3. The supply flow path 12x communicates with the first common liquid chamber 10e and the second common liquid chamber 10f of the cover plate 9, and the discharge flow path 12y communicates with the first to fourth liquid chambers 10a to 10d. That is, the liquid is supplied from the supply flow path 12x to the piezoelectric substrate 2 side, and the liquid is discharged from the discharge flow path 12y. Alternatively, the flow may be reversed.

  The nozzle plate 13 has first to fourth nozzle rows 15 a to 15 d in which nozzles 14 communicating with the ejection grooves 3 are arranged in the reference direction K, and is joined to the lower surface LS of the piezoelectric substrate 2. The nozzle plate 13 is pasted together on the lower surface LS, and then the terminal electrode 7 is formed, and the nozzle plate 13 is removed from the region where the flexible circuit board 8 is connected and the region where the first opening H1 is opened. . That is, each nozzle row 15 can be aligned at a time.

  Thus, since the 1st opening part H1 was provided in the piezoelectric substrate 2, the terminal electrode 7 connected to the groove | channel row | line | column 5 of three or more rows and an external circuit can be electrically connected easily. Further, since the liquid does not come into contact with the drive electrode 6 and the individual terminal electrode 7y installed in the non-ejection groove 4, the drive signal given from the outside does not leak through the liquid, and the drive electrode 6 Electrolysis is not caused on the surface of the wire, and disconnection or the like is not generated. Further, between the first groove row 5a and the second groove row 5b, the end portions of the first discharge groove 3a and the second non-discharge groove 4b and the end portions of the second discharge groove 3b and the first non-discharge groove 4a are piezoelectric. Since it is configured to overlap in the plate thickness direction of the body substrate 2 and both the first discharge groove 3a and the second discharge groove 3b are communicated with the first common liquid chamber 10e, the width in the groove direction is greatly reduced. Can be made. The same applies to the third groove row 5c and the fourth groove row 5d.

  In the present invention, the shapes of the ejection grooves 3 and the non-ejection grooves 4 and the positions of the first ejection grooves 3a to the fourth ejection grooves 3d in the reference direction K are not limited to the present embodiment. Further, for the terminal electrodes 7 installed on the lower surface LS of the piezoelectric substrate 2, the common terminal electrodes 7 x correspond to the first ejection grooves 3 a and the second ejection grooves 3 b, and the end side of the piezoelectric substrate 2 and the first However, the present invention is not limited to this configuration. For example, the interval between the first groove row 5a and the second groove row 5b is widened, and the common terminal electrodes 7x of the first discharge groove 3a and the second discharge groove 3b are arranged between the first groove row 5a and the second groove row 5b. It may be drawn to the lower surface LS to form a common electrode, and the lower surface LS near the end in the reference direction K of the piezoelectric substrate 2 may be drawn and electrically connected to the wiring pattern of the flexible circuit board 8y or 8x. Similarly, the interval between the third groove row 5c and the fourth groove row 5d is widened, and the common terminal electrodes 7x of the third discharge groove 3c and the fourth discharge groove 3d are arranged between the third groove row 5c and the fourth groove row 5d. It may be drawn out to the lower surface LS to form a common electrode, and the lower surface LS near the end of the piezoelectric substrate 2 in the reference direction K may be drawn and electrically connected to the wiring pattern of the flexible circuit board 8y or the flexible circuit board 8x. Thereby, the arrangement pitch of the terminal electrodes 7 is expanded, and electrical connection with the wiring pattern of the flexible circuit board 8 is facilitated.

  Here, a PZT ceramic material can be used as the piezoelectric substrate 2. The piezoelectric substrate 2 is subjected to polarization processing. For example, a piezoelectric substrate 2 that is uniformly polarized in the vertical direction of the upper surface US or the lower surface LS, or a piezoelectric substrate that is polarized in the vertical direction of the upper surface US or the lower surface LS, and the opposite direction. A chevron type piezoelectric substrate bonded to a piezoelectric substrate subjected to polarization treatment can be used. Further, the piezoelectric substrate 2 in the present invention may be any material as long as a piezoelectric material is used for the side wall between at least adjacent grooves, and the peripheral portion of the piezoelectric substrate 2 and the liquid chamber 10 of the cover plate 9 correspond to each other. A non-piezoelectric material may be used for the region to be used.

  The cover plate 9 can be made of a ceramic material, a metal material, a synthetic resin material, or the like. The cover plate 9 is preferably made of a material having a thermal expansion coefficient comparable to that of the piezoelectric substrate 2. As the cover plate 9, for example, PZT ceramics or machinable ceramics can be used.

  The liquid jet head 1 is driven as follows. Liquid is supplied to one of the first liquid chambers 10a, and the liquid is filled in each first discharge groove 3a of the first groove row 5a. Further, the liquid is discharged from each first discharge groove 3a to the other of the first liquid chambers 10a, and the liquid is discharged from the other to the outside. The same applies to the second to fourth liquid chambers 10b to 10d. And the control part mentioned later supplies a drive signal to the terminal electrode 7 from the wiring pattern of flexible circuit board 8x, 8y, gives a drive signal to the drive electrode 6, and comprises the 1st-4th discharge grooves 3a-3d. Thickness deformation is induced on the side wall. For example, droplets are ejected from the nozzle 14 by a pulling method in which the volume of the ejection groove 3 is increased and then contracted.

  The first opening H1 formed in the piezoelectric substrate 2 may be an opening that completely divides the piezoelectric substrate 2, or an opening in which the piezoelectric substrate 2 is not completely divided and remains partially continuous. It may be. Similarly, the second opening H <b> 2 formed in the cover plate 9 may be an opening that completely divides the cover plate 9, or an opening in which the cover plate 9 is not completely divided and remains partially continuous. It may be. In addition, the piezoelectric substrate 2 is divided by the first opening H1, but the cover plate 9 may be configured such that a part of the cover plate 9 remains continuously.

(Control part)
Next, the control unit will be described. FIG. 4 is a schematic block diagram illustrating an example of the control unit 50 in the present embodiment. As shown in the figure, the control unit 50 includes an IC substrate 51 on which a control circuit 52 such as an integrated circuit for driving the liquid ejecting head 1 is mounted, and a flexible circuit substrate 8. In the control unit 50, the control circuit 52 is electrically connected to the drive electrode 6 of the piezoelectric substrate 2 (piezoelectric actuator) via the flexible circuit board 8. As a result, the control circuit 52 can apply a drive voltage to the drive electrode 6 via the flexible circuit board 8.

  The control circuit 52 applies a drive voltage (pulse signal) to the drive electrode 6. As a result, the side wall constituting the ejection groove 3 is deformed, the volume in the ejection groove 3 (pressure chamber) is expanded and contracted, and the ink (liquid) filled in the ejection groove 3 is ejected from the nozzle 14. The ink contains, for example, an inorganic pigment, and the viscosity value at 25 ° C. is in the range from 10 mPa · s (pascal second) to 40 mPa · s.

  Here, the control circuit 52 expands the volume in the ejection groove 3 by applying a positive pulse signal (expansion pulse signal) having a positive drive voltage to the drive electrode 6. In addition, the control circuit 52 contracts the volume in the ejection groove 3 by applying a negative pulse signal (contraction pulse signal) having a negative drive voltage to the drive electrode 6.

  In addition, the control circuit 52 varies the discharge amount (droplet size) of the droplets at a plurality of gradations by using one type of positive pulse signal or a plurality of types of drive waveforms that overlap each other. In other words, the control circuit 52 can discharge droplet sizes with multiple gradations. The droplet size is at least two gradations, for example, the maximum droplet discharge amount of one droplet is 70 pl or more. Thereby, it is possible to cover a small droplet to a large droplet and to improve the image quality.

  The droplet size changes according to the number of times of applying the positive pulse signal. Specifically, the larger the number of positive pulse signals to be applied, the larger the droplet size. Hereinafter, a driving waveform in which a positive pulse signal with a constant voltage is applied n (n is a positive integer) times with a constant pulse width is referred to as an n-drop driving waveform.

  Next, a control method in which the control circuit 52 suppresses crosstalk will be described with reference to FIGS. Nozzles 14 that are adjacent to each other at substantially the same time eject droplets having greatly different discharge amounts (that is, a drive waveform with a small discharge amount and a drive waveform with a large discharge amount are generated at the same time to the nozzle 14 (discharge groove 3)). Crosstalk may occur. In the following, an example will be described in which droplets with a 1-drop driving waveform and droplets with a 7-drop driving waveform are ejected by nozzles 14 that are substantially different (for example, adjacent). In other words, the control circuit 52 generates a 1-drop driving waveform and a 7-drop driving waveform in which the amount of ink discharged is larger than that of the 1-drop driving waveform at different ejection grooves 3 at substantially the same time. 5 to 8, the horizontal axis represents time, the upper row is a 1-drop drive waveform, and the lower row is a 7-drop drive waveform.

[Comparative example]
First, a conventional control method will be described as a comparative example. FIG. 5 is a diagram illustrating an example of a conventional drive waveform. In the example shown in the figure, in a one-drop driving waveform, two positive pulse signals P2 and P3 are applied after one positive pulse signal P1 is applied. On the other hand, in the 7-drop driving waveform, only seven positive pulse signals P11 to P17 are applied. That is, in the 7-drop driving waveform, the negative pulse signal is not applied after the seven positive pulse signals P11 to P17 are applied. The application timing at which the final positive pulse signal P1 in the 1-drop driving waveform is applied and the application timing at which the final positive pulse signal P17 in the 7-drop driving waveform are applied are the same. The final positive pulse signal is a positive pulse signal applied last in the driving waveform. When printing was performed with a combination of the 1-drop drive waveform and the 7-drop drive waveform shown in this figure, there was an effect of crosstalk, and white streaks and density differences increased.

[Shrinkage waveform]
Subsequently, a contraction waveform will be described as a first control method. FIG. 6 is a diagram illustrating an example of a drive waveform output from the control circuit 52. The control circuit 52 applies a negative pulse signal as the final applied pulse signal applied at the end of each drive waveform. In the example shown in this figure, the control circuit 52 applies two negative pulse signals P22 and P23 successively after applying one positive pulse signal P21 in a one-drop driving waveform. The control circuit 52 applies two negative pulse signals P38 and P39 in succession after applying seven positive pulse signals P31 to P37 in a 7-drop driving waveform.

  Here, the application timing of the final positive pulse signal P21 in the 1-drop drive waveform and the application timing of the final positive pulse signal P37 in the 7-drop drive waveform are the same. The application timing t11 and pulse width (t11 to t12) of the first negative pulse signal P22 in the 1-drop driving waveform are the same as those of the first negative pulse signal P38 in the 7-drop driving waveform. The application timing t13 and pulse width (t13 to t14) of the second negative pulse signal P23 in the 1-drop driving waveform are the same as those of the second negative pulse signal P39 in the 7-drop driving waveform. That is, the control circuit 52 applies the negative pulse signals P22 and P23 in the 1-drop driving waveform and the negative pulse signals P38 and P39 in the 7-drop driving waveform simultaneously with the same pulse width. The pulse widths (t11 to t12) of the first negative pulse signals P22 and P38 are larger than the pulse widths (t13 to t14) of the second negative pulse signals P23 and P39. When printing was performed using a combination of the 1-drop driving waveform and the 7-drop driving waveform shown in this figure, white streaks and density differences were reduced as compared with the conventional control method.

  In the present embodiment, the control circuit 52 continuously applies two negative pulse signals as the final application pulse signal. However, the present invention is not limited to this, and the number of negative pulse signals may be one. And three or more.

[Waveform position shift]
Next, waveform position shifting will be described as a second control method. FIG. 7 is a diagram illustrating an example of a drive waveform output from the control circuit 52. The control circuit 52 applies the pulse signal so that the final application timing of the positive pulse signal is earlier in the case of the drive waveform in which the number of overlapping positive pulse signals is larger. That is, the control circuit 52 uses the drive waveform with a small number of superimposed positive pulse signals as the final positive pulse signal of the drive waveform with a large number of superimposed positive pulse signals (that is, the drive waveform with the larger ink ejection amount). That is, it is applied earlier than the final positive pulse signal of the drive waveform having the smaller ink ejection amount.

  In the example shown in the figure, the control circuit 52 applies the final positive pulse signal P57 in the 7-drop drive waveform at a timing t21 earlier than the application timing t22 of the final positive pulse signal P41 in the 1-drop drive waveform. ing. The time from the application timing t21 of the positive pulse signal P57 to the application timing t22 of the positive pulse signal P41 is, for example, in the range from 0.1 μs (microseconds) to 5.0 μs. The control circuit 52 applies two negative pulse signals P42 and P43 in succession after applying the final positive pulse signal P41 in the 1-drop driving waveform, but in the 7-drop driving waveform, the control circuit 52 applies the negative pulse signal P41. Do not apply a pulse signal. When printing was performed using a combination of the 1-drop driving waveform and the 7-drop driving waveform shown in this figure, white streaks and density differences were reduced as compared with the conventional control method.

  FIG. 8 is a diagram illustrating an example of a drive waveform output from the control circuit 52. In this figure, the drive waveform at the time of combining two control methods of a contraction waveform and waveform position shift is shown. In the example shown in the figure, the control circuit 52 applies the final positive pulse signal P77 in the 7-drop drive waveform at a timing t31 earlier than the application timing t32 of the final positive pulse signal P61 in the 1-drop drive waveform. ing. In addition, the control circuit 52 applies two negative pulse signals P62 and P63 in succession after applying one positive pulse signal P61 in a one-drop driving waveform. The control circuit 52 applies two negative pulse signals P78 and P79 in succession after applying seven positive pulse signals P71 to P77 in a 7-drop drive waveform.

  Here, the control circuit 52 simultaneously applies the first negative pulse signal P62 in the 1-drop driving waveform and the first negative pulse signal P78 in the 7-drop driving waveform to the same pulse width (t33 to t33). Apply at t34). Further, the control circuit 52 simultaneously applies the second negative pulse signal P63 in the 1-drop driving waveform and the second negative pulse signal P79 in the 7-drop driving waveform to the same pulse width (t35 to t36). ). The pulse widths (t33 to t34) of the first negative pulse signals P62 and P78 are larger than the pulse widths (t35 to t36) of the second negative pulse signals P63 and P79.

[Timing adjustment]
Next, timing adjustment will be described as a third control method. The control circuit 52 includes nozzles 14 corresponding to the odd-numbered nozzles 14 (the first nozzle row 15a and the third nozzle row 15c) among the nozzles 14 arranged in four rows (four nozzle rows 15) on the plane. Only), the timing of applying the drive waveform is delayed from the timing of applying the ink to a predetermined position. That is, in the control circuit 52, the ejection timing of ejecting ink from the odd-numbered nozzles 14 is based on the ejection timing of the adjacent even-numbered nozzles 14 (the nozzles 14 corresponding to the second nozzle row 15b and the fourth nozzle row 15d). A pulse signal is applied so as to be delayed. That is, the control circuit 52 shifts the ejection timing of the odd-numbered nozzles 14 from the ejection timing of the even-numbered nozzles 14. The delay time for delaying the discharge timing is, for example, in the range of 0.1 μs to 20 μs. When the delay time was set to 5 μs, white streaks and density differences were reduced as compared with the conventional control method.

  In this embodiment, the ejection timing of the odd-numbered nozzles 14 is delayed, but it is only necessary that the ejection timings of the adjacent nozzles 14 are shifted. For example, the ejection timing of the even-numbered nozzles 14 is delayed. May be. In the present embodiment, the liquid jet head 1 in which the nozzles 14 are arranged in four rows on a plane has been described. However, the present invention is not limited to this, and the number of nozzle rows 15 may be two or more.

  Then, the experimental result at the time of implementing the 1st-3rd control method mentioned above is described. 9 and 10 are diagrams illustrating an example of a print image. As shown in FIG. 9, a square area A in the center is printed with 7 drops, and the surrounding area B is verified with a print image G printed with 1 drop. Specifically, in the print image G printed by each control method, the color measurement is performed on the area a and the area b shown in FIG. 10, and ΔE of the area b with respect to the area a is measured. The area a is an area that includes only one drop of printing on one line. That is, the region a is a region where all the nozzles 14 eject one drop of liquid droplets. The area b is an area including 1-drop printing and 7-drop printing on one line. That is, the region b is a region where there are a nozzle 14 for ejecting a drop of one drop and a nozzle 14 for ejecting a drop of seven drops. ΔE is a numerical value indicating a color difference according to ISO: 11664-4. A larger ΔE value indicates a larger color difference, and a smaller ΔE value indicates a smaller color difference. When the density difference is large, the value of ΔE (color difference) also increases. In this embodiment, the color of the printed matter was measured by a colorimeter (X-rite eXact) manufactured by X-Rite.

  FIG. 11 is a table showing the measurement result ΔE under each execution condition. As shown in the figure, the implementation condition (1) Ref. ΔE in (conventional control method) is 2.3. Further, ΔE in the implementation condition (2) contraction waveform (first control method) is 0.9. Further, ΔE in the implementation condition (3) waveform position shift (second control method) is 1.1. Further, ΔE in the implementation condition (4) timing adjustment (third control method) is 1.3. Thus, in any of the first to third control methods, the value of ΔE is smaller than that of the conventional control method. That is, in any of the first to third control methods, there are few white lines and density differences compared to the conventional control method.

  In addition, ΔE under an implementation condition in which (2) the contraction waveform and (3) waveform position shift are combined is 0.7. In addition, ΔE in an implementation condition in which (2) the contraction waveform and (4) timing adjustment are combined is 0.7. In addition, ΔE in an implementation condition in which (3) waveform position shifting and (4) timing adjustment are combined is 1.0. As described above, the combination of the control methods has the effect of reducing the value of ΔE and suppressing crosstalk.

  In addition, ΔE is 0.3 in an implementation condition in which three control methods of (2) contraction waveform, (3) waveform position shift, and (4) timing adjustment are combined. That is, when the three control methods are combined, the value of ΔE becomes the smallest, and there is an effect of further suppressing crosstalk.

  As described above, the liquid jet head 1 included in the liquid jet recording apparatus 30 according to the present embodiment includes a plurality of nozzles 14 that eject liquid, and a plurality of nozzles 14 that correspond to each of the plurality of nozzles 14 and are filled with liquid. The piezoelectric substrate 2 having the discharge groove 3 and changing the volume in the discharge groove 3, and applying a pulse signal to the piezoelectric substrate 2 expands and contracts the volume in the discharge groove 3. In addition to ejecting the liquid filled in 3, one or more expansion pulse signals for expanding the volume in the ejection groove 3 are varied, and the ejection amount of the droplet is varied in a plurality of gradations by a plurality of types of drive waveforms. And a control circuit 52. The control circuit 52 generates a first drive waveform and a second drive waveform having a larger discharge amount than the first drive waveform for different ejection grooves 3, and at least at the end of the second drive waveform, the ejection groove. A contraction pulse signal for contracting the volume in 3 is applied.

  Thereby, without complicating the apparatus configuration, it is possible to easily suppress the influence of crosstalk, reduce white streaks and density differences, and improve print image quality.

  Further, the control circuit 52 applies the final expansion pulse signal of the second drive waveform earlier than the final expansion pulse signal of the first drive waveform, for example, in the range from 0.1 μs to 5.0 μs. . Thereby, the influence of crosstalk can be suppressed, white stripes and density differences can be reduced, and the print image quality can be improved.

  The control circuit 52 applies a plurality of contraction pulse signals continuously. Thereby, the effect which suppresses the influence of crosstalk more is acquired.

  In addition, the plurality of nozzles 14 are arranged in a plurality of rows on the plane, and the control circuit 52 determines that the discharge timing of ejecting the liquid from the nozzles of any nozzle row is the discharge timing of the nozzles of the adjacent nozzle rows. A pulse signal is applied so as to be delayed. As an example, the discharge timing delay time is in the range of 0.1 μs to 20 μs. Thereby, the influence of crosstalk can be suppressed, white stripes and density differences can be reduced, and the print image quality can be improved.

  In addition, for each nozzle row 15 in which each of the plurality of nozzles 14 is arranged, there is one inflow path (supply flow path 12x) filled with liquid, and in a form branched from one inflow path, The nozzle row 15 is filled with liquid. Accordingly, an effect of suppressing the influence of crosstalk can be obtained in the liquid ejecting head 1 having a structure in which the liquid is filled in each nozzle row 15 in a form branched from one inflow path.

  As an example of the discharge amount, the maximum droplet discharge amount of one drop is 70 pl or more. Larger droplets consume more ink instantaneously, resulting in a difference in density. Therefore, the effect of suppressing the influence of crosstalk can be obtained in the liquid ejecting head 1 that ejects large droplets.

  The liquid ejecting head 1 is, for example, a circulation type liquid ejecting head capable of ejecting droplets while circulating liquid. Thereby, an effect of suppressing the influence of crosstalk in the circulation type liquid jet head 1 can be obtained.

  Moreover, the liquid to inject contains an inorganic pigment as an example. Thereby, in the liquid ejecting head 1 that ejects the liquid containing the inorganic pigment, an effect of suppressing the influence of crosstalk is obtained.

  Moreover, the viscosity value at 25 degrees C of the liquid to inject is the range from 10 mPa * s to 40 mPa * s as an example. Accordingly, an effect of suppressing the influence of crosstalk can be obtained in the liquid ejecting head 1 that ejects a liquid having a viscosity value at 25 ° C. in the range of 10 mPa · s to 40 mPa · s.

  The liquid jet recording apparatus 30 is, for example, a line type liquid jet recording apparatus that performs recording in a form in which the liquid jet head 1 is fixed to the liquid jet recording apparatus 30. Thereby, an effect of suppressing the influence of crosstalk in the line type liquid jet recording apparatus 30 is obtained.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the circulation type liquid ejecting head 1 capable of ejecting droplets while circulating ink has been described. However, the present invention is not limited to this, and the non-circulation type liquid ejecting head 1 is also described above. It is possible to employ the configuration of the embodiment. The liquid ejecting head 1 may be a so-called edge chute type that ejects ink from a nozzle facing the longitudinal end of the ejection groove, or ejects ink from a nozzle facing the longitudinal center of the ejection groove. A so-called side shoot type may be used.

  In the above-described embodiments, only the relationship between the 1-drop drive waveform and the 7-drop drive waveform has been described. However, the present invention is not limited to this, and the 2-drop drive waveform, the 6-drop drive waveform, and the 3-drop drive waveform are not limited thereto. Even in the combination of a waveform and another drive waveform having a different discharge amount such as a 5-drop drive waveform, the configuration of the above-described embodiment (for example, applying a contraction pulse signal at the end of the drive waveform having the larger discharge amount). By adopting it, it is possible to suppress the influence of crosstalk, reduce white streaks and density differences, and improve print image quality.

  In the above-described embodiment, the case where the pulse width of the positive pulse signal in the drive waveform is constant has been described as an example. However, an optimal pulse width may be selected according to the ink to be ejected.

  In the above-described embodiment, the case where the positive pulse signal is the expansion pulse signal has been described. However, the expansion pulse signal may be a negative pulse signal as long as it substantially expands the volume in the ejection groove 3. Good. Similarly, the contraction pulse signal may be a positive pulse signal as long as it substantially contracts the volume in the ejection groove 3.

  Note that all or some of the functions of the units included in the control circuit 52 in the above-described embodiment are recorded on a computer-readable recording medium and a program for realizing these functions is recorded on the recording medium. You may implement | achieve by making a computer system read a program and executing it. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage unit such as a hard disk built in the computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  Further, the control circuit 52 in the above-described embodiment may be realized as an integrated circuit such as an LSI (Large Scale Integration). Further, for example, the control circuit 52 may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology, an integrated circuit based on the technology may be used.

DESCRIPTION OF SYMBOLS 1 Liquid ejecting head 2 Piezoelectric substrate 3 Discharge groove, 3a 1st discharge groove, 3b 2nd discharge groove, 3c 3rd discharge groove, 3d 4th discharge groove 4 Non-discharge groove, 4a 1st non-discharge groove, 4b 2nd Non-ejection groove, 4c Third non-ejection groove, 4d
Fourth non-ejection groove 5 Groove row, 5a First groove row, 5b Second groove row, 5c Third groove row, 5d Fourth groove row 6 Drive electrode 7 Terminal electrode, 7x Common terminal electrode, 7y Individual terminal electrode 8, 8x, 8y Flexible circuit board 9 Cover plate 10 Liquid chamber, 10a First liquid chamber, 10b Second liquid chamber, 10c Third liquid chamber, 10d Fourth liquid chamber, 10e First common liquid chamber, 10f Second common liquid chamber 11 Channel plate 12 Channel, 12x Supply channel, 12y Discharge channel 13 Nozzle plate 14 Nozzle 15 Nozzle row, 15a First nozzle row, 15b Second nozzle row, 15c Third nozzle row, 15d Fourth nozzle row 30 Liquid jet recording apparatus 50 Control unit 51 IC substrate 52 Control circuit US Upper surface, LS lower surface, K Reference direction H1 First opening, H2 Second opening, H3 Third opening

Claims (13)

A plurality of nozzles for ejecting liquid;
A plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with a liquid, and a piezoelectric actuator for changing a volume in the pressure chamber;
By applying a pulse signal to the piezoelectric actuator, the volume in the pressure chamber is expanded and contracted, the liquid filled in the pressure chamber is ejected, and an expansion pulse signal for expanding the volume in the pressure chamber is generated. A control unit that varies the discharge amount of the droplets at a plurality of gradations by one or a plurality of types of drive waveforms that are superimposed;
With
The control unit generates a first drive waveform and a second drive waveform having a larger discharge amount than the first drive waveform for different pressure chambers, and at least at the end of the second drive waveform, A contraction pulse signal for contracting the volume in the pressure chamber is applied. The liquid according to claim 1, wherein the control unit applies the final expansion pulse signal of the second drive waveform earlier than the final expansion pulse signal of the first drive waveform. Jet head. The plurality of nozzles are arranged in a plurality of rows on a plane,
The said control part applies the said pulse signal so that the discharge timing which the liquid in a nozzle of arbitrary nozzle rows ejects may be delayed from the discharge timing of the nozzle of an adjacent nozzle row. Item 3. The liquid jet head according to Item 2. The liquid ejecting head according to claim 1, wherein the control unit applies a plurality of the contraction pulse signals continuously. The control unit applies the final expansion pulse signal of the second drive waveform earlier than the final expansion pulse signal of the first drive waveform in a range from 0.1 μs to 5.0 μs. The liquid ejecting head according to claim 2. The liquid ejecting head according to claim 3, wherein the time for delaying the ejection timing is in a range from 0.1 μs to 20 μs. For each nozzle row in which each of the plurality of nozzles is arranged, there is one inflow path filled with the liquid, and each nozzle row is filled with liquid in a form branched from the one inflow path. The liquid ejecting head according to claim 1, wherein the liquid ejecting head is a liquid ejecting head. The liquid ejecting head according to claim 1, wherein a maximum droplet discharge amount of one droplet is 70 pl or more with respect to the discharge amount. The liquid ejecting head according to claim 1, wherein the liquid ejecting head is a circulating liquid ejecting head capable of ejecting liquid droplets while circulating the liquid. . 10. The liquid jet head according to claim 1, wherein a viscosity value of the liquid to be jetted at 25 ° C. is in a range from 10 mPa · s to 40 mPa · s. The liquid ejecting head according to any one of claims 1 to 10,
A liquid jet recording apparatus comprising: The liquid jet recording apparatus according to claim 11, wherein the liquid jet recording apparatus is a line type liquid jet recording apparatus that performs recording in a form in which the liquid jet head is fixed to the liquid jet recording apparatus. A plurality of nozzles for ejecting liquid;
A plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with a liquid, and a piezoelectric actuator for changing a volume in the pressure chamber;
By applying a pulse signal to the piezoelectric actuator, the volume in the pressure chamber is expanded and contracted, the liquid filled in the pressure chamber is ejected, and an expansion pulse signal for expanding the volume in the pressure chamber is generated. A control unit that varies the discharge amount of the droplets at a plurality of gradations by one or a plurality of types of drive waveforms that are superimposed;
A liquid jet head driving method in a liquid jet head comprising:
Generating a first drive waveform and a second drive waveform having a discharge amount larger than that of the first drive waveform for the different pressure chambers;
The controller applying a contraction pulse signal for contracting the volume in the pressure chamber at least at the end of the second drive waveform;
A liquid ejecting head driving method comprising: