Liquid discharge device and liquid discharge method

Abstract

To provide a liquid discharge device and a liquid discharge method which can suppress finely-vibrated ink droplets from being unstably discharged.SOLUTION: A liquid discharge device comprises: a discharge part which has a nozzle, a pressure chamber and pressure generating means; a driving signal generating part that repeatedly generates driving signals including a plurality of pulses including discharge pulses and non-discharge pulses; and a driving control part that supplies, to the pressure generating means, pulses selected from the discharge pulses and the non-discharge pulses, for every repeated periods. When the non-discharge pulses are selected in a precedent period of the two continuous periods of the repeated periods and the discharged pulses are selected in the subsequent period, a pulse interval T1 between the non-discharge pulse in the precedent period and the discharge pulse in the subsequent period satisfies either of the following formulas (1) or (2): 1.7×Tc×n≤T1≤1.9×Tc×n (1) and 1.2×Tc×n≤T1≤1.4×Tc×n (2).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection apparatus and a liquid ejection method. [Background technology]

[0002] 2. Description of the Related Art Liquid ejection devices equipped with a liquid ejection head that ejects liquid such as ink onto a medium such as printing paper have been proposed.

[0003] The liquid ejection head described in Patent Document 1 includes a piezoelectric vibrator that vibrates the ink in the nozzle, a micro-vibration control signal generating means that generates a micro-vibration control signal, and a control unit that drives the piezoelectric vibrator based on the micro-vibration control signal. The micro-vibration control signal includes a drive pulse that vibrates the meniscus, which is the surface of the ink exposed in the nozzle opening, for nozzles that do not eject ink droplets. When the micro-vibration control signal is supplied to the piezoelectric vibrator, the meniscus of the nozzle vibrates micro-vibrates, stirring the ink in the nozzle opening. This micro-vibration operation suppresses thickening of the liquid in the nozzle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-1951 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the micro-vibration of the meniscus for stirring the ink in the nozzle is increased, there is a problem in that the ejection of the ink droplets immediately thereafter tends to become unstable. [Means for solving the problem]

[0006] A liquid ejection device according to one aspect of the present disclosure includes an ejection section having a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating a pressure fluctuation in a liquid in the pressure chamber, a drive signal generating section which repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse, and a drive control section which supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, wherein the ejection pulse is a pulse whose potential changes such that the pressure generating means generates the pressure fluctuation so that liquid is ejected from the nozzle, and the non-ejection pulse is a pulse whose potential changes such that the pressure generating means generates the pressure fluctuation so that liquid is not ejected from the nozzle, and when the non-ejection pulse is selected in the preceding period and the ejection pulse is selected in the succeeding period of two consecutive periods in the repeating periods, a pulse interval T1 between the non-ejection pulse in the preceding period and the ejection pulse in the succeeding period satisfies either of the following formulas (1) and (2). 1.7×Tc×n≦T1≦1.9×Tc×n (1) 1.2×Tc×n≦T1≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

[0007] A liquid ejection device according to one aspect of the present disclosure includes an ejection section having a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating a pressure fluctuation in a liquid in the pressure chamber, a drive signal generating section which repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse, and a drive control section which supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, wherein the ejection pulse is a pulse whose potential changes such that the pressure generating means generates the pressure fluctuation so that liquid is ejected from the nozzle, and the non-ejection pulse is a pulse whose potential changes such that the pressure generating means generates the pressure fluctuation so that liquid is not ejected from the nozzle, and when the non-ejection pulse is selected in the preceding period and the ejection pulse is selected in the succeeding period of two consecutive periods in the repeating periods, a connection interval T2 between the non-ejection pulse in the preceding period and the ejection pulse in the succeeding period satisfies either of the following formulas (1) and (2). 1.7×Tc×n≦T2≦1.9×Tc×n (1) 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

[0008] A liquid ejection method according to one aspect of the present disclosure is a liquid ejection method executed by a liquid ejection device capable of ejecting liquid, the liquid ejection device comprising: an ejection section having a nozzle, a pressure chamber communicating with the nozzle, and pressure generating means for generating pressure fluctuations in the liquid in the pressure chamber; a drive signal generating section configured to repeatedly generate a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse; and a drive control section configured to supply a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeated period, the ejection pulse being a pulse generated by the pressure generating means. The non-ejection pulse is a pulse whose potential changes so that the pressure generating means generates the pressure fluctuation so that liquid is ejected from the nozzle, and the non-ejection pulse is a pulse whose potential changes so that the pressure generating means generates the pressure fluctuation so that liquid is not ejected from the nozzle, and when the non-ejection pulse is selected in the preceding period and the ejection pulse is selected in the succeeding period out of two consecutive periods in the repeating period, the pulse interval T1 between the non-ejection pulse in the preceding period and the ejection pulse in the succeeding period satisfies either of the following equations (1) and (2). 1.7×Tc×n≦T1≦1.9×Tc×n (1) 1.2×Tc×n≦T1≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

[0009] A liquid ejection method according to one aspect of the present disclosure is a liquid ejection method executed by a liquid ejection device capable of ejecting liquid, the method comprising the steps of: The liquid ejection device includes: the non-ejection pulse is a pulse whose potential changes so that the pressure generating means generates the pressure fluctuation so that liquid is ejected from the nozzle, and the non-ejection pulse is a pulse whose potential changes so that the pressure generating means generates the pressure fluctuation so that liquid is ejected from the nozzle, and the non-ejection pulse is a pulse whose potential changes so that the pressure generating means generates the pressure fluctuation so that liquid is not ejected from the nozzle, and when the non-ejection pulse is selected in the preceding cycle and the ejection pulse is selected in the succeeding cycle of two consecutive cycles of the repeating cycles, a connection interval T2 between the non-ejection pulse in the preceding cycle and the ejection pulse in the succeeding cycle satisfies either of the following formulas (1) and (2). 1.7×Tc×n≦T2≦1.9×Tc×n (1) 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of a liquid ejection device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an electrical configuration of the liquid ejection device according to the first embodiment. [Diagram 3] 5A and 5B are schematic diagrams illustrating circulation channels of a liquid ejection head. [Figure 4] 4 is a cross-sectional view taken along the line A1-A1 in FIG. [Diagram 5] FIG. [Figure 6] FIG. 4 is a diagram for explaining a drive control unit. [Figure 7] FIG. 4 is a diagram for explaining a drive signal. [Figure 8]11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 9] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 10] FIG. 11 is a diagram showing the relationship between the pulse interval and the ink droplet velocity in the first shot. [Figure 11] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 12] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 13] FIG. 11 is a diagram showing the relationship between the pulse interval and the ink droplet velocity in the first shot. [Figure 14] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 15] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 16] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 17] 11 is a diagram for explaining a pulse interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 18] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 19] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 20] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 21] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 22] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 23] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 24] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Diagram 25] 13 is a diagram showing a connection interval between a non-ejection pulse and an ejection pulse. FIG. [Figure 26]FIG. 11 is a diagram for explaining a drive signal in a first modified example. [Figure 27] 11A and 11B are diagrams for explaining the pulse interval and connection interval between a non-ejection pulse and an ejection pulse. [Figure 28] 11A and 11B are diagrams for explaining the pulse interval and connection interval between a non-ejection pulse and an ejection pulse. [Figure 29] FIG. 11 is a diagram for explaining a drive signal in a second modified example. [Diagram 30] 13 is a schematic diagram illustrating a circulation flow path of a liquid ejection head according to a third modified example. FIG. [Diagram 31] 31 is a cross-sectional view taken along line A2-A2 in FIG. 30. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. In addition, the scope of the present disclosure is not limited to these forms unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0012] The following description will be given using the mutually intersecting X-axis, Y-axis, and Z-axis as appropriate. In addition, in the following, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, the mutually opposite directions along the Y-axis are the Y1 direction and the Y2 direction. The mutually opposite directions along the Z-axis are the Z1 direction and the Z2 direction. Typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z-axis does not have to be a vertical axis. In addition, the X-axis, Y-axis, and Z-axis are typically perpendicular to each other, but are not limited thereto, and may intersect at an angle within a range of 80° to 100°, for example.

[0013] 1: First embodiment 1A: Overall configuration of liquid ejection device 100 1 is a schematic diagram showing an example of the configuration of a liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects liquid such as ink as droplets onto a medium M. The medium M is, for example, printing paper. Note that the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0014] As shown in FIG. 1, the liquid ejection device 100 includes a liquid container 10, a control unit 20, a transport mechanism 30, a moving mechanism 40, a liquid ejection head 50, and a circulation mechanism 60.

[0015] The liquid container 10 stores ink. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of a flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the liquid container 10 is arbitrary.

[0016] The control unit 20 controls the operation of each element of the liquid ejection device 100. The control unit 20 includes, for example, one or more processing circuits such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits such as a semiconductor memory.

[0017] The transport mechanism 30 transports the medium M in the Y1 direction under the control of the control unit 20. The movement mechanism 40 reciprocates the liquid ejection head 50 along the X axis under the control of the control unit 20. The movement mechanism 40 has a substantially box-shaped carriage 41 that houses the liquid ejection head 50, and an endless transport belt 42 to which the carriage 41 is fixed. The number of liquid ejection heads 50 mounted on the carriage 41 is not limited to one, and may be multiple. In addition to the liquid ejection head 50, the above-mentioned liquid container 10 may be mounted on the carriage 41.

[0018] Under the control of the control unit 20, the liquid ejection head 50 ejects ink supplied from the liquid container 10 from each of a plurality of nozzles onto the medium M. This ejection is performed in parallel with the transportation of the medium M by the transport mechanism 30 and the reciprocating movement of the liquid ejection head 50 by the movement mechanism 40, thereby forming an image in ink on the surface of the medium M.

[0019] The liquid container 10 is connected to the liquid ejection head 50 via a circulation mechanism 60. The circulation mechanism 60 is a mechanism that, under the control of the control unit 20, supplies ink to the liquid ejection head 50 and collects ink discharged from the liquid ejection head 50 for re-supply to the liquid ejection head 50.

[0020] 1B: Electrical configuration of the liquid ejection device 100 2 is a diagram showing the electrical configuration of the liquid ejection device 100 according to the first embodiment. As shown in FIG.

[0021] The head chip 51 has a plurality of ejection parts 510. Under the control of the control unit 20, the drive control unit 52 switches whether or not to supply the drive signal Com output from the control unit 20 as the supply signal Vin to each of the plurality of ejection parts 510 of the head chip 51. In the example shown in FIG. 2, the head chip 51 has M ejection parts 510. M is a natural number of 1 or more. Hereinafter, the m-th ejection part 510 of the M ejection parts 510 may be referred to as the ejection part 510m. m is a natural number satisfying "1≦m≦M". In addition, in the following, when a component or signal of the liquid ejection head 50 corresponds to the ejection part 510m of the M ejection parts 510, the subscript m may be added to the symbol for representing the component or signal.

[0022] As shown in FIG. 2, the control unit 20 includes a control circuit 21, a memory circuit 22, a power supply circuit 23, and a drive signal generating section 24.

[0023] The control circuit 21 has a function of controlling the operation of each part of the liquid ejection device 100 and a function of processing various data. The control circuit 21 includes, for example, one or more processors such as a CPU (Central Processing Unit). Note that the control circuit 21 may include a programmable logic device such as an FPGA (field-programmable gate array) instead of or in addition to a CPU. Furthermore, when the control circuit 21 is composed of multiple processors, the multiple processors may be mounted on different boards or the like.

[0024] The memory circuit 22 stores various programs executed by the control circuit 21 and various data such as print data Img processed by the control circuit 21. The memory circuit 22 includes one or both of semiconductor memories, for example, a volatile memory such as a random access memory (RAM) and a non-volatile memory such as a read only memory (ROM), an electrically erasable programmable read-only memory (EEPROM) or a programmable ROM (PROM). The print data Img is supplied from an external device 200 such as a personal computer or a digital camera. The memory circuit 22 may be configured as a part of the control circuit 21.

[0025] The power supply circuit 23 receives power from a commercial power supply (not shown) and generates various predetermined potentials. The generated various potentials are appropriately supplied to each section of the liquid ejection device 100. For example, the power supply circuit 23 generates a power supply potential VHV and an offset potential VBS. The offset potential VBS is supplied to the liquid ejection head 50. In addition, the power supply potential VHV is supplied to the drive signal generation section 24.

[0026] The drive signal generating unit 24 is a circuit that repeatedly generates a drive signal Com for driving each pressure generating means 51e. Specifically, the drive signal generating unit 24 has, for example, a DA conversion circuit and an amplifier circuit. In the drive signal generating unit 24, the DA conversion circuit converts the waveform designation signal dCom from the control circuit 21 from a digital signal to an analog signal. The amplifier circuit amplifies the analog signal using the power supply potential VHV from the power supply circuit 23, thereby generating the drive signal Com. Of the waveforms contained in the drive signal Com, the signal having the waveform that is actually supplied to the pressure generating means 51e is the aforementioned supply signal Vin. The waveform designation signal dCom is a digital signal for defining the waveform of the drive signal Com.

[0027] The control circuit 21 executes a program stored in the memory circuit 22 to control the operation of each part of the liquid ejection device 100. Here, the control circuit 21 generates control signals Sk1 and Sk2, a print data signal SI, a waveform designation signal dCom, a latch signal LAT, a change signal CNG, and a clock signal CLK as signals for controlling the operation of each part of the liquid ejection device 100 by executing the program.

[0028] The control signal Sk1 is a signal for controlling the driving of the transport mechanism 30. The control signal Sk2 is a signal for controlling the driving of the movement mechanism 40. The print data signal SI is a digital signal for specifying the operating state of the pressure generating means 51e. The latch signal LAT and the change signal CNG are used in conjunction with the print data signal SI and are timing signals that define the timing of ink ejection from each nozzle of the head chip 51. These timing signals are generated, for example, based on the output of an encoder that detects the position of the carriage 41 described above.

[0029] 1C: Flow path of liquid ejection head 50 Fig. 3 is a schematic diagram for explaining the circulation flow path of the liquid ejection head 50. As shown in Fig. 3, the liquid ejection head 50 is provided with a plurality of nozzles N, a plurality of individual flow paths IP, a first common liquid chamber R1, and a second common liquid chamber R2. A circulation mechanism 60 is connected to the first common liquid chamber R1 and the second common liquid chamber R2. The individual flow paths IP, the first common liquid chamber R1, and the second common liquid chamber R2 form a circulation flow path.

[0030] The multiple nozzles N are arranged along the Y axis. Each of the multiple nozzles N ejects ink in the Z2 direction. A group of the multiple nozzles N constitutes a nozzle row L. The multiple nozzles N are also arranged at equal intervals.

[0031] An individual flow path IP communicates with each of the plurality of nozzles N. Each of the plurality of individual flow paths IP extends along the X-axis and communicates with a different nozzle N. Furthermore, the plurality of individual flow paths IP are arranged along the Y-axis.

[0032] Each individual flow path IP has a pressure chamber Ca, a pressure chamber Cb, a communication flow path Nf, an individual supply flow path Ra1, and an individual discharge flow path Ra2.

[0033] Each of the pressure chambers Ca and pressure chambers Cb in each individual flow path IP extends along the X-axis and is a space in which ink ejected from a nozzle N communicating with the individual flow path IP is stored. In the example shown in FIG. 3, the multiple pressure chambers Ca are arranged along the Y-axis. Similarly, the multiple pressure chambers Cb are arranged along the Y-axis. Note that, in each individual flow path IP, the positions of the pressure chambers Ca and pressure chambers Cb in the direction along the Y-axis are the same in the example shown in FIG. 3, but may be different from each other. In the following, when there is no particular distinction between the pressure chambers Ca and pressure chambers Cb, they are also simply referred to as "pressure chambers C."

[0034] A communication flow path Nf is disposed between the pressure chamber Ca and the pressure chamber Cb in each individual flow path IP. In each individual flow path IP, the communication flow path Nf is a flow path that communicates the pressure chamber Ca and the pressure chamber Cb. Furthermore, the multiple communication flow paths Nf are arranged along the Y axis at intervals from one another. A nozzle N is provided in each communication flow path Nf. In each communication flow path Nf, ink is ejected from the nozzle N due to pressure fluctuations in the pressure chamber Ca and the pressure chamber Cb described above.

[0035] Each individual flow path IP is provided with an individual supply flow path Ra1 between the pressure chamber Ca and the first common liquid chamber R1. The individual supply flow path Ra1 is a flow path that connects the pressure chamber Ca and the first common liquid chamber R1. Similarly, each individual flow path IP is provided with an individual discharge flow path Ra2 between the pressure chamber Cb and the second common liquid chamber R2. The individual discharge flow path Ra2 is a flow path that connects the pressure chamber Cb and the second common liquid chamber R2.

[0036] The individual flow paths IP are commonly connected to a first common liquid chamber R1 and a second common liquid chamber R2. Each of the first common liquid chamber R1 and the second common liquid chamber R2 is a space extending along the Y axis over the entire range in which the nozzles N are distributed. When viewed in the direction along the Z axis, the individual flow paths IP are located between the first common liquid chamber R1 and the second common liquid chamber R2.

[0037] The first common liquid chamber R1 is connected to an end E1 of each individual flow path IP in the X2 direction. Ink to be supplied to each individual flow path IP is stored in the first common liquid chamber R1. Meanwhile, the second common liquid chamber R2 is connected to an end E2 of each individual flow path IP in the X1 direction. Ink that is not ejected and is discharged from each individual flow path IP is stored in the second common liquid chamber R2.

[0038] A circulation mechanism 60 is connected to the first common liquid chamber R1 and the second common liquid chamber R2. The circulation mechanism 60 supplies ink to the first common liquid chamber R1 and recovers ink discharged from the second common liquid chamber R2 for re-supply to the first common liquid chamber R1. The circulation mechanism 60 has a first supply pump 61, a second supply pump 62, a storage container 63, a recovery flow path 64, and a supply flow path 65.

[0039] The first supply pump 61 is a pump that supplies the ink stored in the liquid container 10 to the storage container 63. The storage container 63 is a sub-tank that temporarily stores the ink supplied from the liquid container 10. The recovery flow path 64 communicates the second common liquid chamber R2 with the storage container 63, and is a flow path for recovering the ink from the second common liquid chamber R2 to the storage container 63. In addition to the ink stored in the liquid container 10 being supplied from the first supply pump 61 to the storage container 63, the ink discharged from each individual flow path IP to the second common liquid chamber R2 is supplied via the recovery flow path 64. The second supply pump 62 is a pump that sends out the ink stored in the storage container 63. The supply flow path 65 communicates the first common liquid chamber R1 with the storage container 63, and is a flow path for supplying the ink from the storage container 63 to the first common liquid chamber R1.

[0040] 1D: Specific structure of head chip 51 Fig. 4 is a cross-sectional view taken along the line A1-A1 in Fig. 3. Fig. 4 shows a cross section of head chip 51 cut along an individual flow path IP and a plane perpendicular to the Y axis. As shown in Fig. 4, head chip 51 has a nozzle substrate 51a, a flow path substrate 51b, a pressure chamber substrate 51c, a vibration plate 51d, a plurality of pressure generating means 51e, a case 51f, a protective plate 51g, and a wiring substrate 51h.

[0041] The nozzle substrate 51a, the flow path substrate 51b, the pressure chamber substrate 51c, and the vibration plate 51d are stacked in this order toward the Z1 direction. Each of these members extends along the Y axis, and is manufactured, for example, by processing a single crystal silicon substrate using semiconductor processing technology. These members are also bonded to each other with an adhesive or the like. Note that another layer such as an adhesive layer or a substrate may be appropriately interposed between two adjacent members among these members.

[0042] The nozzle substrate 51a is provided with a plurality of nozzles N. Each of the plurality of nozzles N extends along the Z axis and penetrates the nozzle substrate 51a, and is a through hole that allows ink to pass through.

[0043] The flow path substrate 51b is provided with the above-mentioned portions of the individual flow paths IP excluding the pressure chambers Ca and Cb, a liquid chamber R1a which is a part of the first common liquid chamber R1, and a liquid chamber R2a which is a part of the second common liquid chamber R2. That is, the flow path substrate 51b is provided with the communication flow path Nf, the individual supply flow path Ra1, the individual discharge flow path Ra2, the liquid chamber R1a, and the liquid chamber R2a.

[0044] Each of the liquid chambers R1a and R2a is a space penetrating the flow path substrate 51b. A vibration absorber 51i that closes the opening of the space is provided on the surface of the flow path substrate 51b facing the Z2 direction.

[0045] The vibration absorber 51i is a layered member made of an elastic material. The vibration absorber 51i constitutes a part of the wall surface of each of the first common liquid chamber R1 and the second common liquid chamber R2, and absorbs pressure fluctuations in the first common liquid chamber R1 and the second common liquid chamber R2.

[0046] The communication flow path Nf has a first communication flow path Na1, a second communication flow path Na2, and a nozzle flow path Nfa. The first communication flow path Na1 and the second communication flow path Na2 are each a space penetrating the flow path substrate 51b. The first communication flow path Na1 and the second communication flow path Na2 communicate with each other via the nozzle flow path Nfa. The first communication flow path Na1 communicates the pressure chamber Ca with the nozzle flow path Nfa. The second communication flow path Na2 communicates the pressure chamber Cb with the nozzle flow path Nfa. The nozzle flow path Nfa is a space within a groove provided on a surface of the flow path substrate 51b facing the Z2 direction, and extends along the X axis. The nozzle substrate 51a forms a part of the wall surface of the nozzle flow path Nfa.

[0047] Each of the individual supply flow passages Ra1 and the individual discharge flow passages Ra2 is a space penetrating the flow passage substrate 51b. The individual supply flow passage Ra1 communicates the first common liquid chamber R1 with the pressure chamber Ca, and supplies ink from the first common liquid chamber R1 to the pressure chamber Ca. One end of the individual supply flow passage Ra1 opens to a surface of the flow passage substrate 51b facing the Z1 direction. On the other hand, the other end of the individual supply flow passage Ra1 is an upstream end of the individual flow passage IP, and opens to a wall surface of the first common liquid chamber R1 in the flow passage substrate 51b. On the other hand, the individual discharge flow passage Ra2 communicates the second common liquid chamber R2 with the pressure chamber Cb, and discharges ink from the pressure chamber Cb to the second common liquid chamber R2. One end of the individual discharge flow passage Ra2 opens to a surface of the flow passage substrate 51b facing the Z1 direction. On the other hand, the other end of the individual discharge flow path Ra2 is the downstream end of the individual flow path IP, and opens into the wall surface of the second common liquid chamber R2 in the flow path substrate 51b.

[0048] The pressure chamber substrate 51c is provided with pressure chambers Ca and pressure chambers Cb of a plurality of individual flow paths IP. Each of the pressure chambers Ca and pressure chambers Cb penetrates the pressure chamber substrate 51c and is a gap between the flow path substrate 51b and the vibration plate 51d. The pressure chamber Ca communicates with the nozzle N via the first communication flow path Na1 and the nozzle flow path Nfa. The pressure chamber Cb communicates with the nozzle N via the second communication flow path Na2 and the nozzle flow path Nfa.

[0049] The diaphragm 51d is a plate-like member capable of elastically vibrating. The diaphragm 51d is, for example, a laminate including a first layer made of silicon oxide (SiO2) and a second layer made of zirconium oxide (ZrO2). Another layer such as a metal oxide may be interposed between the first layer and the second layer. A part or all of the diaphragm 51d may be integrally formed with the pressure chamber substrate 51c using the same material. For example, the diaphragm 51d and the pressure chamber substrate 51c can be integrally formed by selectively removing a part in the thickness direction from a region corresponding to the pressure chamber C in a plate-like member of a predetermined thickness. The diaphragm 51d may also be formed from a layer of a single material.

[0050] A plurality of pressure generating means 51e corresponding to different pressure chambers C are provided on the surface of the vibration plate 51d facing the Z1 direction. The pressure generating means 51e is a piezoelectric element that generates pressure fluctuations in the liquid in the pressure chambers C. Each pressure generating means 51e is, for example, configured by laminating a first electrode and a second electrode facing each other and a piezoelectric layer disposed between the two electrodes. Each pressure generating means 51e ejects the ink in the pressure chambers C from the nozzles N by fluctuating the pressure of the ink in the pressure chambers C. When a drive signal Com is supplied, the pressure generating means 51e vibrates the vibration plate 51d in accordance with its own deformation. The pressure chambers C expand and contract in accordance with this vibration, and the pressure of the ink in the pressure chambers C fluctuates.

[0051] The case 51f is a case for storing ink. The case 51f is provided with a liquid chamber R1b, which is a portion other than the liquid chamber R1a of the first common liquid chamber R1, a liquid chamber R2b, which is a portion other than the liquid chamber R2a of the second common liquid chamber R2, an inlet port R01, and an outlet port R02. The liquid chamber R1b and the liquid chamber R2b are each a recess provided on the surface of the case 51f facing the Z2 direction. The inlet port R01 is a through hole formed by an inner circumferential surface extending from the surface of the case 51f facing the Z1 direction to the wall surface of the liquid chamber R1b. The inlet port R01 is connected to the supply flow path 65 of the circulation mechanism 60 described above. The outlet port R02 is a through hole formed by an inner circumferential surface extending from the surface of the case 51f facing the Z1 direction to the wall surface of the liquid chamber R2b. The outlet port R02 is connected to the recovery flow path 64 of the circulation mechanism 60 described above.

[0052] The protective plate 51g is a plate-like member installed on the surface of the diaphragm 51d facing the Z1 direction, and protects the multiple pressure generating means 51e and reinforces the mechanical strength of the diaphragm 51d. Here, a space for accommodating the multiple pressure generating means 51e is formed between the protective plate 51g and the diaphragm 51d.

[0053] The wiring board 51h is mounted on the surface of the diaphragm 51d facing the Z1 direction, and is a mounting component for electrically connecting the control unit 20 and the head chip 51. For example, a flexible wiring board 51h such as an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable) is preferably used. The drive control unit 52 described above is mounted on the wiring board 51h.

[0054] In the head chip 51 configured as above, ink flows through the first common liquid chamber R1, the individual supply flow path Ra1, the pressure chamber Ca, the communication flow path Nf, the pressure chamber Cb, the individual discharge flow path Ra2, and the second common liquid chamber R2 in this order by the operation of the above-mentioned circulation mechanism 60. Also, the pressure generating means 51e corresponding to both the pressure chamber Ca and the pressure chamber Cb are simultaneously driven by a supply signal Vin from the drive control unit 52, thereby fluctuating the pressure in the pressure chamber Ca and the pressure chamber Cb, and ink is ejected from the nozzle N in accordance with the pressure fluctuation.

[0055] In the head chip 51, the aforementioned ejection section 510 includes a nozzle N, a pressure chamber C, and a pressure generating means 51e. In this embodiment, the ejection section 510 is configured by the nozzle N, the pressure chamber Ca, the pressure chamber Cb, the individual supply flow path Ra1, the individual discharge flow path Ra2, the communication flow path Nf, the two pressure generating means 51e, and the vibration plate 51d.

[0056] 1E: Nozzle N Fig. 5 is an enlarged cross-sectional view of the nozzle N. Fig. 5 shows a cross section of a part of the nozzle flow path Nfa and the nozzle N perpendicular to the Y-axis. As shown in Fig. 5, the nozzle N branches off from the nozzle flow path Nfa and extends in a direction different from the nozzle flow path Nfa. Specifically, the nozzle flow path Nfa extends in the direction along the X-axis, while the nozzle N extends in the direction along the Z-axis.

[0057] The nozzle N is a through hole formed in the nozzle substrate 51a and includes a discharge side opening end N1 and a connection portion N2. The discharge side opening end N1 is an opening end of the nozzle N on a surface of the nozzle substrate 51a facing the Z2 direction. The connection portion N2 is a boundary portion with the nozzle flow path Nfa of the nozzle N. The length along the Z axis from the discharge side opening end N1 to the connection portion N2 is the length L of the nozzle N.

[0058] 5, the nozzle N has a first portion NP1 and a second portion NP2. The first portion NP1 and the second portion NP2 are arranged in this order in the Z1 direction. The second portion NP2 is provided between the nozzle flow path Nfa and the first portion NP1. The nozzle flow path Nfa and the first portion NP1 communicate with each other via the second portion NP2.

[0059] Each of the first portion NP1 and the second portion NP2 extends along the Z-axis. The cross-sectional area of ​​each of the first portion NP1 and the second portion NP2 is circular. The first portion NP1 and the second portion NP2 are arranged coaxially. The first portion NP1 includes a discharge-side opening end N1. The second portion NP2 includes a connection portion N2.

[0060] The length L1 of the first portion NP1 is shorter than the length L2 of the second portion NP2. The length L1 is the length along the Z axis from the discharge side opening end N1 to the boundary between the first portion NP1 and the second portion NP2. The length L2 is the length along the Z axis from the boundary between the first portion NP1 and the second portion NP2 to the connection portion N2.

[0061] The cross-sectional area of ​​the first portion NP1 is smaller than the cross-sectional area of ​​the second portion NP2. Therefore, the nozzle N has a shape in which the width gradually decreases in the Z2 direction. The width W1 of the first portion NP1 is smaller than the width W2 of the second portion NP2. By making the width W1 smaller than the width W2, it is possible to eject finer ink droplets and improve the landing accuracy of the ink droplets compared to when the width is constant. In addition, it is preferable that the width W2 is smaller than the width of the nozzle flow path Nfa. By making the width W2 smaller than the width of the nozzle flow path Nfa, it is possible to reduce crosstalk between two second portions NP2 adjacent to each other in the direction along the Y axis.

[0062] Note that width W1 is the length of the first portion NP1 in a direction perpendicular to the Z axis. Width W2 is the length of the second portion NP2 in a direction perpendicular to the Z axis. Since the cross-sectional areas of the first portion NP1 and the second portion NP2 are circular, width W1 corresponds to the diameter of the first portion NP1, and width W2 corresponds to the diameter of the second portion NP2. Furthermore, the width of the nozzle flow path Nfa is the length along the Z axis.

[0063] Furthermore, the specific values ​​of the length L1 are not particularly limited, but are determined appropriately depending on the characteristics such as the ink ejection amount or ejection speed required for the nozzle N. The specific value of the length L2 is determined appropriately depending on the width W2 of the second portion NP2 or the thickness of the nozzle substrate 51a, etc. Furthermore, the specific values ​​of the widths W1 and W2 are not particularly limited, but are determined appropriately depending on the characteristics such as the ink ejection amount or ejection speed required for the nozzle N, for example.

[0064] As described above, the nozzle N extends in a direction intersecting the direction in which the nozzle flow path Nfa extends. Therefore, even if the circulation mechanism 60 described above is operated, the circulating flow of ink generated in the nozzle flow path Nfa by the operation is unlikely to reach the inside of the nozzle N. In particular, in the nozzle N having the first portion NP1 and the second portion NP2 as described above, it is necessary to ensure a certain degree of length in the Z-axis direction for each of the first portion NP1 and the second portion NP2. Therefore, in the nozzle N of this embodiment, the circulating flow is unlikely to reach the first portion NP1 compared to a nozzle of a constant width. Therefore, during the period in which the pressure generating means 51e is not operated, the ink is likely to stagnate in the nozzle N. Therefore, if this period continues for a long period of time, it may lead to an increase in the viscosity of the ink in the nozzle N.

[0065] Therefore, in the liquid ejection device 100, during a period when ink is not ejected from the nozzle N, the pressure generating means 51e is driven to vibrate the meniscus MN slightly so that ink is not ejected from the nozzle N. This vibration is smaller than the vibration of the meniscus MN when ink is ejected. This vibration agitates the ink in the nozzle N. Therefore, coupled with the action of the circulating flow of ink by the circulation mechanism 60, the replacement of ink is smoothly performed between the nozzle N and the nozzle flow path Nfa. This makes it possible to prevent the ink in the nozzle N from thickening, etc.

[0066] 1F: Driving the liquid ejection head 50 Fig. 6 is a diagram for explaining the drive control unit 52. As described above, the drive control unit 52 supplies the drive signal Com output from the drive signal generating unit 24 to the pressure generating means 51e as the supply signal Vin. The pressure generating means 51e is driven by the supply signal Vin from the drive control unit 52. In the example shown in Fig. 6, the drive signal Com includes a first drive signal Com-A, a second drive signal Com-B, a third drive signal Com-C, a fourth drive signal Com-D, a fifth drive signal Com-E, and a sixth drive signal Com-F.

[0067] The drive control unit 52 is connected to wirings LHa, LHb, LHc, LHd, LHe, and LHf. The wiring LHa is a signal line that transmits the first drive signal Com-A. The wiring LHb is a signal line that transmits the second drive signal Com-B. The wiring LHc is a signal line that transmits the third drive signal Com-C. The wiring LHd is a signal line that transmits the fourth drive signal Com-D. The wiring LHe is a signal line that transmits the fifth drive signal Com-E. The wiring LHf is a signal line that transmits the sixth drive signal Com-F. In FIG. 6, one of the first electrode and the second electrode of the pressure generating means 51e described above is shown as an electrode Zd[m], and the other is shown as an electrode Zu[m]. The wiring LHg is connected to the electrode Zd[m]. The wiring LHg is a power supply line to which an offset potential VBS is supplied.

[0068] The drive control unit 52 has M switches SWa, M switches SWb, M switches SWc, M switches SWd, M switches SWe, and M switches SWf, and a connection state designation circuit 52a that designates the connection states of these switches.

[0069] The switch SWa[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHa for transmitting the first drive signal Com-A and the electrode Zu[m] of the pressure generating means 51e[m]. The switch SWb[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHb for transmitting the second drive signal Com-B and the electrode Zu[m] of the pressure generating means 51e[m]. The switch SWc[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHc for transmitting the third drive signal Com-C and the electrode Zu[m] of the pressure generating means 51e[m]. The switch SWd[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHd for transmitting the fourth drive signal Com-D and the electrode Zu[m] of the pressure generating means 51e[m]. The switch SWe[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHe for transmitting the fifth drive signal Com-E and the electrode Zu[m] of the pressure generating means 51e[m]. The switch SWf[m] is a switch that switches between conduction (on) and non-conduction (off) between the wiring LHf for transmitting the sixth drive signal Com-F and the electrode Zu[m] of the pressure generating means 51e[m]. Each of these switches is, for example, a transmission gate.

[0070] The connection state designation circuit 52a generates the connection state designation signals SLa[m], SLb[m], SLc[m], SLd[m], SLe[m], and SLf[m] based on the clock signal CLK, the print data signal SI, the latch signal LAT, and the change signal CNG supplied from the control circuit 21. Specifically, the connection state designation circuit 52a generates the connection state designation signals SLa[1] to SLa[M] that specify the on / off states of the switches SWa[1] to SWa[M]. The connection state designation circuit 52a generates the connection state designation signals SLb[1] to SLb[M] that specify the on / off states of the switches SWb[1] to SWb[M]. The connection state designation circuit 52a generates the connection state designation signals SLc[1] to SLc[M] that specify the on / off states of the switches SWc[1] to SWc[M]. The connection state designation circuit 52a generates connection state designation signals SLd[1] to SLd[M] that designate the on / off states of the switches SWd[1] to SWd[M]. The connection state designation circuit 52a generates connection state designation signals SLe[1] to SLe[M] that designate the on / off states of the switches SWe[1] to SWe[M]. The connection state designation circuit 52a generates connection state designation signals SLf[1] to SLf[M] that designate the on / off states of the switches SWf[1] to SWf[M].

[0071] For example, although not shown, the connection state designation circuit 52a has a plurality of transfer circuits, a plurality of latch circuits, and a plurality of decoders so as to correspond one-to-one to the pressure generating means 51e[1] to 51e[M]. Of these, the print data signal SI is supplied to the transfer circuit. The print data signal SI includes an individual designation signal for each pressure generating means 51e, and the individual designation signal is supplied serially. For example, the print data signal SI includes an individual designation signal that is transferred to the plurality of transfer circuits in sequence in synchronization with a clock signal CLK. Furthermore, the latch circuit latches the individual designation signal supplied to the transfer circuit based on the latch signal LAT. Furthermore, the decoder generates the connection state designation signals SLa[m], SLb[m], SLc[m], SLd[m], SLe[m], and SLf[m] based on the individual designation signal, the latch signal LAT, and the change signal CNG.

[0072] For example, the switch SWa[m] is in an on state when the connection state designation signal SLa[m] is at a high level, and in an off state when the connection state designation signal SLa[m] is at a low level. For example, the switch SWb[m] is in an on state when the connection state designation signal SLb[m] is at a high level, and in an off state when the connection state designation signal SLa[m] is at a high level, and in an off state when the connection state designation signal SLa[m] is at a low level. For example, the switch SWc[m] is in an on state when the connection state designation signal SLC[m] is at a high level, and in an off state when the connection state designation signal SLC[m] is at a low level. For example, the switch SWe[m] is in an on state when the connection state designation signal SLe[m] is at a high level, and in an off state when the connection state designation signal SLC[m] is at a low level. For example, the switch SWf[m] is in an on state when the connection state designation signal SLC[m] is at a high level, and in an off state when the connection state designation signal SLC[m] is at a low level.

[0073] 1G: Drive signal Fig. 7 is a diagram for explaining the drive signal Com. As shown in Fig. 7, the latch signal LAT includes a pulse PlsL for defining a repeating period Tu. The period Tu corresponds to a printing period for forming dots of ink from the nozzles N on the medium M. The period Tu is defined as, for example, the period from the rising edge of the pulse PlsL to the rising edge of the next pulse PlsL.

[0074] The first drive signal Com-A has an ejection pulse P1. The ejection pulse P1 is a pulse whose potential changes to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e ejects ink from the nozzle N. When the ejection pulse P1 is supplied to the pressure generating means 51e, ink is ejected from the nozzle N as an ink droplet.

[0075] The ejection pulse P1 includes a second expansion driving element s1, a minimum potential s2, a contraction driving element s3, a maximum potential s4, and an expansion driving element s5 in this order. The minimum potential s2 is the minimum value of the voltage of the ejection pulse P1. The maximum potential s4 is the maximum value of the voltage of the ejection pulse P1. The second expansion driving element s1 is a falling edge from the reference potential to the minimum potential s2. The second expansion driving element s1 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The contraction driving element s3 is a rising edge from the minimum potential s2 to the maximum potential s4. The contraction driving element s3 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The expansion driving element s5 is a falling edge that returns from the maximum potential s4 to the reference potential. The expansion driving element s5 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The reference potential is, for example, a potential higher than the offset potential VBS.

[0076] The second drive signal Com-B has an ejection pulse P2. The ejection pulse P2 is a pulse whose potential changes to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e ejects ink from the nozzle N. When the ejection pulse P2 is supplied to the pressure generating means 51e, ink is ejected from the nozzle N as an ink droplet.

[0077] The ejection pulse P2 includes a preparatory contraction driving element u1, a high potential u2, an expansion driving element u3, a minimum potential u4, a contraction driving element u5, a maximum potential u6, and an expansion driving element u7 in this order. The minimum potential u4 is the minimum value of the voltage of the ejection pulse P2. The maximum potential u6 is the maximum value of the voltage of the ejection pulse P2. The high potential u2 is a potential higher than the reference potential and lower than the maximum potential u6. The preparatory contraction driving element u1 is a rising edge from the reference potential toward the high potential u2. The preparatory contraction driving element u1 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The expansion driving element u3 is a falling edge from the high potential u2 toward the minimum potential u4. The expansion driving element u3 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The contraction driving element u5 is a rising edge from the minimum potential u4 toward the maximum potential u6. The contraction driving element u5 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The expansion driving element u7 is a falling edge that returns from the maximum potential u6 to the reference potential. The expansion driving element u7 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C.

[0078] The third drive signal Com-C has a non-ejection pulse P01. The non-ejection pulse P01 is a pulse that changes potential so as to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e does not eject ink from the nozzle N. By supplying the non-ejection pulse P01 to the pressure generating means 51e, the meniscus MN of the ink in the nozzle N is slightly vibrated without ejecting ink from the nozzle N.

[0079] The non-ejection pulse P01 includes a first expansion driving element a1, a minimum potential a2, and a first contraction driving element a3, in this order. The minimum potential s2 is the minimum value of the voltage of the non-ejection pulse P01. The first expansion driving element a1 is a falling edge from the reference potential to the minimum potential a2. The first expansion driving element a1 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first contraction driving element a3 is a rising edge from the minimum potential s2 to the reference potential. It is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C.

[0080] The fourth drive signal Com-D has a non-ejection pulse P02. The non-ejection pulse P02 is a pulse that changes potential so as to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e does not eject ink from the nozzle N. By supplying the non-ejection pulse P02 to the pressure generating means 51e, the meniscus MN of the ink in the nozzle N is slightly vibrated without ejecting ink from the nozzle N.

[0081] The non-ejection pulse P02, like the non-ejection pulse P01, includes a first expansion driving element a1, a minimum potential a2, and a first contraction driving element a3, in this order. The non-ejection pulse P02 and the non-ejection pulse P01 differ in the start timing of the first expansion driving element a1. The start timing of the non-ejection pulse P02 is later than the start timing of the non-ejection pulse P01.

[0082] The fifth drive signal Com-E has a non-ejection pulse P03. The non-ejection pulse P03 is a pulse that changes potential so as to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e does not eject ink from the nozzle N. By supplying the non-ejection pulse P03 to the pressure generating means 51e, the meniscus MN of the ink in the nozzle N is slightly vibrated without ejecting ink from the nozzle N.

[0083] The non-ejection pulse P03 includes a first contraction driving element b1, a maximum potential b2, and a first expansion driving element b3, in this order. The maximum potential b2 is the maximum value of the voltage of the non-ejection pulse P02. The first contraction driving element b1 is a rising edge from the reference potential to the maximum potential b2. The first contraction driving element b1 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The first expansion driving element b3 is a falling edge from the maximum potential b2 to the reference potential. The first expansion driving element b3 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C.

[0084] The sixth drive signal Com-F has a non-ejection pulse P04. The non-ejection pulse P04 is a pulse that changes potential so as to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e does not eject ink from the nozzle N. By supplying the non-ejection pulse P04 to the pressure generating means 51e, the meniscus MN of the ink in the nozzle N is slightly vibrated without ejecting ink from the nozzle N.

[0085] The non-ejection pulse P04, like the non-ejection pulse P03, includes a first contraction driving element b1, a maximum potential b2, and a first expansion driving element b3, in this order. The non-ejection pulse P04 and the non-ejection pulse P03 differ in the start timing of the first expansion driving element a1. The start timing of the non-ejection pulse P04 is later than the start timing of the non-ejection pulse P03.

[0086] The drive signal generating unit 24 repeatedly generates a drive signal Com including a plurality of pulses such as the above-mentioned ejection pulses P1, P2, and non-ejection pulses P01, P02, P03, and P04. The ejection pulses P1, P2, and non-ejection pulses P01, P02, P03, and P04 are appropriately selected and used for the supply signal Vin. When the ejection pulse P1 or P2 is selected, ink is ejected from the nozzle N. When the non-ejection pulse P01, P02, P03, or P04 is selected, ink is not ejected from the nozzle N and the ink in the nozzle N slightly vibrates.

[0087] 1H: Time interval between non-ejection pulse and ejection pulse As described above, in order to suppress thickening of the ink in the nozzle N, the meniscus MN of the ink in the nozzle N is vibrated slightly during periods when ink is not being ejected. This vibration agitates the ink in the nozzle N. However, if the vibration is increased in order to agitate the ink in the nozzle N, the residual vibration of the meniscus MN caused by the vibration will cause the ejection of ink to become unstable immediately after the vibration. This can result in a deterioration of image quality.

[0088] In this embodiment, in order to prevent the ink ejection from becoming unstable immediately after the micro-vibration, the time interval between the non-ejection pulse P01, P02, P03 or P04 and the ejection pulse P1 or P2 is set to a specific pulse interval T1.

[0089] Fig. 8 is a diagram showing the pulse interval T1 between the non-ejection pulse P01 and the ejection pulse P1. Fig. 9 is a diagram showing the pulse interval T1 between the non-ejection pulse P02 and the ejection pulse P1. Fig. 8 shows an example in which, of two consecutive periods Tu in a repeating period Tu, the non-ejection pulse P01 is selected in the preceding period Tua, and the ejection pulse P1 is selected in the following period Tub. Fig. 9 shows an example in which the non-ejection pulse P02 is selected in the preceding period Tua, and the ejection pulse P1 is selected in the following period Tub.

[0090] Each of the non-ejection pulses P01 and P02 initially includes a first expansion drive element a1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The ejection pulse P1 initially includes a second expansion drive element s1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first expansion drive element a1 and the second expansion drive element s1 are in phase.

[0091] The pulse interval T1 between the preceding non-ejection pulse P01 or P02 of the period Tua and the following ejection pulse P1 of the period Tub satisfies the following formula (1): 1.7×Tc×n≦T1≦1.9×Tc×n (1) The natural vibration period of the ejection part 510 is denoted by Tc, and n is a natural number.

[0092] By the pulse interval T1 satisfying the above formula (1), the ink ejection after the micro-vibration is prevented from becoming unstable, compared to when the formula is not satisfied. The pulse interval T1 in Fig. 8 and Fig. 9 is the time interval between the half-value point A1 of the period of the first expansion driving element a1 of the non-ejection pulse P01 or P02 and the half-value point S1 of the period of the second expansion driving element s1 of the ejection pulse P1. The half-value point A1 is a value 50% increased from the minimum potential a2 of the first expansion driving element a1. The half-value point S1 is a value 50% increased from the minimum potential s2 of the second expansion driving element s1.

[0093] FIG. 10 is a diagram showing the relationship between the pulse interval T1 and the ink droplet velocity Vm of the first shot. FIG. 10 shows the result of the ink droplet velocity Vm of the first shot when the pulse interval T1 is changed. The horizontal axis of FIG. 10 indicates the pulse interval T1, and the vertical axis of FIG. 10 indicates the ink droplet velocity Vm of the first shot. FIG. 10 shows the result of the ink droplet velocity Vm of the first shot when a non-ejection pulse including a first expansion drive element a1 is applied first, and then an ejection pulse including a second expansion drive element s1 is applied first. That is, FIG. 10 shows the result when the first drive element of the non-ejection pulse and the first drive element of the ejection pulse are in phase.

[0094] When the pressure vibration applied to the liquid in the pressure chamber C by the first driving element of the ejection pulse resonates with the residual vibration of the micro-vibration, the ink droplet speed becomes faster. When the ink droplet speed is fast, it approaches the dotted line L01 in the example of Figure 10. As the ink droplet speed increases, the landing speed of the ink droplet on the medium M becomes faster. On the other hand, when the pressure vibration applied to the liquid in the pressure chamber C by the first driving element of the ejection pulse damps the residual vibration of the micro-vibration, the ink droplet speed becomes slow. When the ink droplet speed is slow, it approaches the dotted line L02 in the example of Figure 10. As the ink droplet speed decreases, the landing speed of the ink droplet on the medium M becomes slower. Also, the longer the pulse interval T1 is, i.e., in the case of low frequency drive, the smaller the change in ink droplet speed due to the residual vibration of the micro-vibration becomes, converging to a certain value.

[0095] When such a change in ink droplet speed occurs, there is a risk of image quality degradation. In particular, when the ink droplet speed of the first shot, which is affected by the residual vibration, is greater than the ink droplet speed of the subsequent second shot, there is a risk of white streaks appearing on the medium M, for example. Furthermore, the higher the driving frequency, the more likely the pulse interval T1 becomes to be shorter. Therefore, the ink ejection is more likely to be affected by the residual waveform caused by micro-vibrations. For this reason, the higher the driving frequency, the more likely image quality degradation occurs due to the above-mentioned change in ink droplet speed.

[0096] As can be seen from FIG. 10, in order to suppress the influence of residual vibration due to micro-vibration, it is preferable to set the pulse interval T1 so that the ink droplet speed is between dotted line L01 and dotted line L02. In other words, it is preferable that the timing is such that the ink droplet speed of the first shot is unlikely to resonate with or be damped by the residual vibration of the micro-vibration. Specifically, when the ejection pulse P1 is supplied immediately after the non-ejection pulse P01 or P02, the ink droplet speed of the first shot is unlikely to be influenced by the residual vibration due to the micro-vibration by the pulse interval T1 satisfying the above-mentioned formula (1). This prevents the ink ejection after the micro-vibration from becoming unstable. This makes it possible to suppress deterioration in image quality.

[0097] As described above, n in formula (1) may be any natural number, but is preferably 1. When n is 1, it is easier to adapt to high-speed driving compared to when n is 2 or more.

[0098] Also, from the viewpoint of making the ink droplet speed less susceptible to the effects of micro-vibrations, n in formula (1) may be a natural number x 0.5 rather than a natural number. However, by using a natural number for n, the ink ejection stability can be improved compared to when n is a natural number x 0.5.

[0099] Moreover, which of the non-ejection pulses P01 and P02 is applied in the period Tua immediately before the period Tub in which the ejection pulse P1 is applied is appropriately selected, for example, according to the natural vibration period Tc of the ejection section 510. The natural vibration period Tc varies appropriately depending on, for example, individual differences in the liquid ejection head 50 and the type of ink. For example, when the natural vibration period Tc exceeds a predetermined value, the non-ejection pulse P01 is selected, and when the natural vibration period Tc is equal to or less than the predetermined value, the non-ejection pulse P02 is selected.

[0100] Moreover, it is preferable that the pulse width T3 of each of the non-ejection pulses P01 and P02 shown in Figures 8 and 9 is 0.5Tc. By setting the pulse width T3 to 0.5Tc, it is possible to reduce unintended vibration of the meniscus MN of the ink in the nozzle N compared to other cases. Therefore, it is possible to reduce ejection defects caused by the vibration, and the ink is preferably stirred by the micro-vibration. Note that the pulse width T3 may be other than 0.5Tc. Furthermore, the natural vibration period Tc is, for example, 4 μsec or more and 12 μsec or less.

[0101] 8 and 9, the pulse width T3 is the time interval between the half-value point A1 and the half-value point A2 of the non-ejection pulse P01 or P02. The half-value point A2 is a value that is 50% reduced from the minimum potential a2 of the first contraction driving element a3.

[0102] Fig. 11 is a diagram showing the pulse interval T1 between a non-ejection pulse P01 and an ejection pulse P2. Fig. 12 is a diagram showing the pulse interval T1 between a non-ejection pulse P02 and an ejection pulse P2. Fig. 11 shows an example in which a non-ejection pulse P01 is selected in a preceding period Tua, and an ejection pulse P2 is selected in a following period Tub. Fig. 12 shows an example in which a non-ejection pulse P02 is selected in a preceding period Tua, and an ejection pulse P2 is selected in a following period Tub.

[0103] Each of the non-ejection pulses P01 and P02 initially includes a first expansion drive element a1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The ejection pulse P2 initially includes a preparatory contraction drive element u1 that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The first expansion drive element a1 and the preparatory contraction drive element u1 are in opposite phase.

[0104] The pulse interval T1 between the preceding non-ejection pulse P01 or P02 of the period Tua and the following ejection pulse P2 of the period Tub satisfies the following formula (2): 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection part 510 is denoted by Tc, and n is a natural number.

[0105] By the pulse interval T1 satisfying the above formula (2), the ink ejection after the micro-vibration is prevented from becoming unstable, compared to when the formula is not satisfied. The pulse interval T1 in Fig. 11 and Fig. 12 is the time interval between the half-value point A1 of the period of the first expansion driving element a1 of the non-ejection pulse P01 or P02 and the half-value point U1 of the period of the preparatory contraction driving element u1 of the ejection pulse P2. The half-value point A1 is a value that is 50% increased from the minimum potential a2 of the first expansion driving element a1. The half-value point U1 is a value that is 50% decreased from the high potential u2 of the preparatory contraction driving element u1.

[0106] FIG. 13 is a diagram showing the relationship between the pulse interval T1 and the ink droplet velocity Vm of the first shot. FIG. 13 shows the result of the ink droplet velocity Vm of the first shot when the pulse interval T1 is changed. The horizontal axis of FIG. 13 indicates the pulse interval T1, and the vertical axis of FIG. 10 indicates the ink droplet velocity Vm of the first shot. FIG. 13 shows the result of the ink droplet velocity Vm of the first shot when an ejection pulse including a preparatory contraction drive element u1 is applied first after a non-ejection pulse including a first expansion drive element a1 is applied first. That is, FIG. 10 shows the result when the first drive element of the non-ejection pulse and the first drive element of the ejection pulse are in opposite phase.

[0107] When the pressure vibration applied to the liquid in the pressure chamber C by the first driving element of the ejection pulse resonates with the residual vibration caused by the micro vibration, the landing speed of the ink droplets on the medium M becomes faster. On the other hand, when the pressure vibration applied to the liquid in the pressure chamber C by the first driving element of the ejection pulse damps the residual vibration caused by the micro vibration, the landing speed of the ink droplets on the medium M becomes slower. The longer the pulse interval T1 is, that is, in the case of low frequency drive, the smaller the change in ink droplet speed due to the residual vibration of the micro vibration becomes and converges to a certain value. When such a change in ink droplet speed occurs, there is a risk of image quality degradation. In addition, the higher the frequency of drive, the more likely the pulse interval T1 is to become shorter. Therefore, the ejection of ink is more likely to be affected by the residual waveform caused by the micro vibration. For this reason, the higher the frequency of drive, the more likely the image quality degradation due to the change in ink droplet speed described above occurs.

[0108] As can be seen from Fig. 13, in order to suppress the effects of residual vibration due to micro-vibrations, it is preferable to set the pulse interval T1 so that the ink droplet speed is between dotted lines L01 and L02. Specifically, when an ejection pulse P2 is supplied immediately after a non-ejection pulse P01 or P02, the pulse interval T1 satisfies the above-mentioned formula (2), so that the ink droplet speed of the first shot is less susceptible to the effects of residual vibration due to micro-vibrations. This prevents the ink ejection after micro-vibrations from becoming unstable. This makes it possible to suppress deterioration in image quality.

[0109] Furthermore, n in formula (2) may be any natural number, but is preferably 1. When n is 1, it is easier to adapt to high-speed driving than when n is 2 or more.

[0110] Also, from the viewpoint of making the ink droplet speed less susceptible to the effects of micro-vibrations, n in formula (2) may be a natural number × 0.5 rather than a natural number. However, by using a natural number for n, the ink ejection stability can be improved compared to when n is a natural number × 0.5.

[0111] Fig. 14 is a diagram showing the pulse interval T1 between the non-ejection pulse P03 and the ejection pulse P1. Fig. 15 is a diagram showing the pulse interval T1 between the non-ejection pulse P04 and the ejection pulse P1. Fig. 14 shows an example in which the non-ejection pulse P03 is selected in the preceding period Tua, and the ejection pulse P1 is selected in the following period Tub. Fig. 15 shows an example in which the non-ejection pulse P04 is selected in the preceding period Tua, and the ejection pulse P1 is selected in the following period Tub.

[0112] Each of the non-ejection pulses P03 and P04 initially includes a first contraction driving element b1 that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The ejection pulse P1 initially includes a second expansion driving element s1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first contraction driving element b1 and the second expansion driving element s1 are in opposite phase.

[0113] The pulse interval T1 between the preceding non-ejection pulse P03 or P04 of the cycle Tua and the following ejection pulse P1 of the cycle Tub satisfies the above-mentioned formula (2). That is, when the first driving element of the non-ejection pulse is the first contraction driving element b1 and the first driving element of the ejection pulse is the second expansion driving element s1, the pulse interval T1 satisfies formula (2). When the pulse interval T1 satisfies formula (2), the ejection of ink after micro-vibration is prevented from becoming unstable, compared to when formula (2) is not satisfied. Therefore, deterioration in image quality can be suppressed.

[0114] 14 and 15, the pulse interval T1 is the time interval between the half-value point B1 of the period of the first contraction driving element b1 of the non-ejection pulse P03 or P04 and the half-value point S1 of the period of the second expansion driving element s1 of the ejection pulse P1. The half-value point B1 is a value that is 50% lower than the maximum potential b2 of the first contraction driving element b1. The half-value point S1 is a value that is 50% higher than the minimum potential s2 of the second expansion driving element s1.

[0115] Fig. 16 is a diagram showing the pulse interval T1 between the non-ejection pulse P03 and the ejection pulse P2. Fig. 17 is a diagram showing the pulse interval T1 between the non-ejection pulse P04 and the ejection pulse P2. Fig. 16 shows an example in which the non-ejection pulse P03 is selected in the preceding period Tua, and the ejection pulse P2 is selected in the following period Tub. Fig. 17 shows an example in which the non-ejection pulse P04 is selected in the preceding period Tua, and the ejection pulse P2 is selected in the following period Tub.

[0116] Each of the non-ejection pulses P03 and P04 initially includes a first contraction drive element b1 that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The ejection pulse P2 initially includes a preparatory contraction drive element u1 that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The first contraction drive element b1 and the preparatory contraction drive element u1 are in phase.

[0117] The pulse interval T1 between the preceding non-ejection pulse P03 or P04 of the cycle Tua and the following ejection pulse P2 of the cycle Tub satisfies the above-mentioned formula (1). That is, when the first drive element of the non-ejection pulse is the first contraction drive element b1 and the first drive element of the ejection pulse is the preparatory contraction drive element u1, the pulse interval T1 satisfies formula (1). When the pulse interval T1 satisfies formula (1), the ejection of ink after micro-vibration is prevented from becoming unstable, compared to when formula (1) is not satisfied. Therefore, deterioration in image quality can be suppressed.

[0118] 16 and 17, the pulse interval T1 is the time interval between the half-value point B1 of the period of the first contraction driving element b1 of the non-ejection pulse P03 or P04 and the half-value point U1 of the period of the preparatory contraction driving element u1 of the ejection pulse P2. The half-value point B1 is a value that is 50% reduced from the maximum potential b2 of the first contraction driving element b1. The half-value point U1 is a value that is 50% reduced from the high potential u2 of the preparatory contraction driving element u1. The natural vibration period Tc of the ejection unit 510 differs as appropriate depending on, for example, individual differences in the liquid ejection head 50 and the type of ink. Therefore, which of the non-ejection pulses P01, P02, P03, and P04 is applied in the period Tua immediately before the period Tub in which the ejection pulse P1 is applied is selected by selecting the non-ejection pulses P01 and P02 whose pulse interval T1 with the ejection pulse P1 satisfies formula (1), or the non-ejection pulses P03 and P04 whose pulse interval T1 with the ejection pulse P1 satisfies formula (2). In addition, which of the non-ejection pulses P01, P02, P03, and P04 is applied in the period Tua immediately before the period Tub in which the ejection pulse P2 is applied is selected based on whether the non-ejection pulses P01 and P02 have a pulse interval T1 with the ejection pulse P2 that satisfies formula (2), or whether the non-ejection pulses P03 and P04 have a pulse interval T1 with the ejection pulse P2 that satisfies formula (1).

[0119] As described above, when the first driving element of the non-ejection pulse and the first driving element of the ejection pulse immediately after the application of the non-ejection pulse are in phase, the pulse interval T1 satisfies formula (1). When the first driving element of the non-ejection pulse and the first driving element of the ejection pulse immediately after the application of the non-ejection pulse are in opposite phase, the pulse interval T1 satisfies formula (2). In this way, the liquid ejection method executed by the liquid ejection device 100 drives so that the pulse interval T1 satisfies formula (1) or (2). According to this method, the influence of residual vibration due to the micro-vibration of the meniscus MN caused by the application of the non-ejection pulse is suppressed from affecting the ejection of ink immediately after the micro-vibration. Therefore, the ejection of ink after the micro-vibration is suppressed from becoming unstable. Therefore, deterioration of image quality can be suppressed.

[0120] 2. Second embodiment A second embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions or functions are similar to those of the first embodiment, the reference symbols used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0121] In the first embodiment, the pulse interval T1 is set to prevent the ink ejection from becoming unstable after the micro-vibration. In contrast, in this embodiment, the connection interval T2 is set to prevent the ink ejection from becoming unstable after the micro-vibration.

[0122] Fig. 18 is a diagram showing a connection interval T2 between a non-ejection pulse P01 and an ejection pulse P1. Fig. 19 is a diagram showing a connection interval T2 between a non-ejection pulse P02 and an ejection pulse P1. Fig. 18 shows an example in which a non-ejection pulse P01 is selected in a preceding cycle Tua, and an ejection pulse P1 is selected in a following cycle Tub. Fig. 19 shows an example in which a non-ejection pulse P02 is selected in a preceding cycle Tua, and an ejection pulse P1 is selected in a following cycle Tub.

[0123] Each of the non-ejection pulses P01 and P02 includes a first contraction driving element a3 at the end, which drives the pressure generating means 51e to contract the volume of the pressure chamber C. The ejection pulse P1 includes a second expansion driving element s1 at the beginning, which drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first contraction driving element a3 and the second expansion driving element s1 are in opposite phase.

[0124] The connection interval T2 between the preceding non-ejection pulse P01 or P02 of the period Tua and the following ejection pulse P1 of the period Tub satisfies formula (2). 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection part 510 is denoted by Tc, and n is a natural number.

[0125] When the last driving element of the non-ejection pulse is the first contraction driving element a3 and the first driving element of the ejection pulse is the second expansion driving element s1, the connection interval T2 satisfies the formula (2). When the connection interval T2 satisfies the above formula (2), the ink ejection after the micro-vibration is prevented from becoming unstable, as in the first embodiment, compared to when the connection interval T2 does not satisfy the formula (2).

[0126] 18 and 19, the connection interval T2 is the time interval between the half-value point A2 of the period of the first contraction driving element a3 of the non-ejection pulse P01 or P02 and the half-value point S1 of the period of the second expansion driving element s1 of the ejection pulse P1. The half-value point A2 is a value 50% increased from the minimum potential a2 of the first contraction driving element a3. The half-value point S3 is a value 50% increased from the minimum potential s2 of the second expansion driving element s1.

[0127] Furthermore, n in formula (2) may be any natural number, but is preferably 1. When n is 1, it is easier to adapt to high-speed driving compared to when n is 2 or more.

[0128] Also, from the viewpoint of suppressing resonance and vibration of the ink droplet velocity, n in formula (2) may be a natural number × 0.5 rather than a natural number. However, by using a natural number for n, the ink ejection stability can be improved compared to when n is a natural number × 0.5.

[0129] 18 and 19, the pulse width T3 of each of the non-ejection pulses P01 and P02 is preferably 0.5Tc, as in the first embodiment. By setting the pulse width T3 to 0.5Tc, it is possible to reduce unintended vibration of the meniscus MN of the ink in the nozzle N, compared to other cases. This makes it possible to reduce ejection defects caused by the vibration, and the ink is preferably stirred by the micro-vibration.

[0130] Fig. 20 is a diagram showing a connection interval T2 between a non-ejection pulse P01 and an ejection pulse P2. Fig. 21 is a diagram showing a connection interval T2 between a non-ejection pulse P02 and an ejection pulse P2. Fig. 20 shows an example in which a non-ejection pulse P01 is selected in a preceding cycle Tua, and an ejection pulse P2 is selected in a following cycle Tub. Fig. 21 shows an example in which a non-ejection pulse P02 is selected in a preceding cycle Tua, and an ejection pulse P2 is selected in a following cycle Tub.

[0131] Each of the non-ejection pulses P01 and P02 includes a first contraction drive element a3 at the end, which drives the pressure generating means 51e to contract the volume of the pressure chamber C. The ejection pulse P2 includes a preparatory contraction drive element u1 at the beginning, which drives the pressure generating means 51e to contract the volume of the pressure chamber C. The first contraction drive element a3 and the preparatory contraction drive element u1 are in phase.

[0132] The connection interval T2 between the preceding non-ejection pulse P01 or P02 of the cycle Tua and the following ejection pulse P2 of the cycle Tub satisfies formula (1). 1.7×Tc×n≦T1≦1.9×Tc×n (1) The natural vibration period of the ejection part 510 is denoted by Tc, and n is a natural number.

[0133] When the last drive element of the non-ejection pulse is the first contraction drive element a3 and the first drive element of the ejection pulse is the preparatory contraction drive element u1, the connection interval T2 satisfies the formula (1). When the connection interval T2 satisfies the above formula (1), the ink ejection after the micro-vibration is prevented from becoming unstable, as in the first embodiment, compared to when the connection interval T2 does not satisfy the formula (1).

[0134] 20 and 21, the connection interval T2 is the time interval between the half-value point A2 of the period of the first contraction driving element a3 of the non-ejection pulse P01 or P02 and the half-value point U1 of the period of the preparatory contraction driving element u1 of the ejection pulse P2. The half-value point A2 is a value that is 50% increased from the minimum potential a2 of the first contraction driving element a3. The half-value point U1 is a value that is 50% decreased from the high potential u2 of the preparatory contraction driving element u1.

[0135] Furthermore, n in formula (1) may be any natural number, but is preferably 1. When n is 1, it is easier to adapt to high-speed driving compared to when n is 2 or more.

[0136] Also, from the viewpoint of suppressing resonance and vibration of the ink droplet velocity, n in formula (1) may be a natural number × 0.5 rather than a natural number. However, by using a natural number for n, the ink ejection stability can be improved compared to when n is a natural number × 0.5.

[0137] Fig. 22 is a diagram showing a connection interval T2 between a non-ejection pulse P03 and an ejection pulse P1. Fig. 23 is a diagram showing a connection interval T2 between a non-ejection pulse P04 and an ejection pulse P1. Fig. 22 shows an example in which a non-ejection pulse P03 is selected in a preceding cycle Tua, and an ejection pulse P1 is selected in a following cycle Tub. Fig. 23 shows an example in which a non-ejection pulse P04 is selected in a preceding cycle Tua, and an ejection pulse P1 is selected in a following cycle Tub.

[0138] Each of the non-ejection pulses P03 and P04 includes a first expansion drive element b3 at the end, which drives the pressure generating means 51e to expand the volume of the pressure chamber C. The ejection pulse P1 includes a second expansion drive element s1 at the beginning, which drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first expansion drive element b3 and the second expansion drive element s1 are in phase.

[0139] The connection interval T2 between the preceding non-ejection pulse P03 or P04 of the cycle Tua and the following ejection pulse P1 of the cycle Tub satisfies the above-mentioned formula (1). That is, when the last driving element of the non-ejection pulse is the first expansion driving element b3 and the first driving element of the ejection pulse is the second expansion driving element s1, the connection interval T2 satisfies the formula (1). By making the connection interval T2 satisfy the above formula (1), compared to when it does not satisfy the formula, the ink ejection after micro-vibration is prevented from becoming unstable, as in the first embodiment.

[0140] 21 and 23, the connection interval T2 is the time interval between the half-value point B2 of the period of the first expansion driving element b3 of the non-ejection pulse P03 or P04 and the half-value point S1 of the period of the second expansion driving element s1 of the ejection pulse P1. The half-value point B3 is a value that is 50% lower than the maximum potential b2 of the first expansion driving element b3. The half-value point S1 is a value that is 50% higher than the minimum potential s2 of the second expansion driving element s1.

[0141] Fig. 24 is a diagram showing a connection interval T2 between a non-ejection pulse P03 and an ejection pulse P2. Fig. 25 is a diagram showing a connection interval T2 between a non-ejection pulse P04 and an ejection pulse P2. Fig. 24 shows an example in which a non-ejection pulse P03 is selected in a preceding cycle Tua, and an ejection pulse P2 is selected in a following cycle Tub. Fig. 25 shows an example in which a non-ejection pulse P04 is selected in a preceding cycle Tua, and an ejection pulse P2 is selected in a following cycle Tub.

[0142] Each of the non-ejection pulses P03 and P04 includes a first expansion drive element b3 at the end, which drives the pressure generating means 51e to expand the volume of the pressure chamber C. The ejection pulse P2 includes a preparatory contraction drive element u1 at the beginning, which drives the pressure generating means 51e to contract the volume of the pressure chamber C. The first expansion drive element b3 and the preparatory contraction drive element u1 are in opposite phase.

[0143] The connection interval T2 between the preceding non-ejection pulse P03 or P04 of the cycle Tua and the subsequent ejection pulse P2 of the cycle Tub satisfies the above-mentioned formula (2). That is, when the last driving element of the non-ejection pulse is the first expansion driving element b3 and the first driving element of the ejection pulse is the preparatory contraction driving element u1, the connection interval T2 satisfies the formula (2). By making the connection interval T2 satisfy the above formula (2), compared to when it does not satisfy the formula, the ink ejection after micro-vibration is prevented from becoming unstable, as in the first embodiment.

[0144] 24 and 25, the connection interval T2 is the time interval between the half-value point B2 of the period of the first expansion driving element b3 of the non-ejection pulse P03 or P04 and the half-value point U1 of the period of the preparatory contraction driving element u1 of the ejection pulse P2. The half-value point B3 is a value that is 50% reduced from the maximum potential b2 of the first expansion driving element b3. The half-value point U1 is a value that is 50% reduced from the high potential u2 of the preparatory contraction driving element u1. The natural vibration period Tc of the ejection unit 510 differs as appropriate depending on, for example, individual differences in the liquid ejection head 50, the type of ink, etc. Therefore, which of the non-ejection pulses P01, P02, P03, and P04 is applied in the period Tua immediately before the period Tub in which the ejection pulse P1 is applied is selected by selecting the non-ejection pulses P01 and P02 whose connection interval T2 with the ejection pulse P1 satisfies formula (2), or the non-ejection pulses P03 and P04 whose connection interval T2 with the ejection pulse P1 satisfies formula (1). In addition, which of the non-ejection pulses P01, P02, P03, and P04 is applied in the period Tua immediately preceding the period Tub in which the ejection pulse P2 is applied is selected based on whether the non-ejection pulses P01 and P02 have a connection interval T2 with the ejection pulse P2 that satisfies formula (1), or whether the non-ejection pulses P03 and P04 have a connection interval T2 with the ejection pulse P2 that satisfies formula (2).

[0145] As described above, when the last driving element of the non-ejection pulse and the first driving element of the ejection pulse immediately after the application of the non-ejection pulse are in phase, the connection interval T2 satisfies formula (1). When the last driving element of the non-ejection pulse and the first driving element of the ejection pulse immediately after the application of the non-ejection pulse are in opposite phase, the connection interval T2 satisfies formula (2). In this way, the liquid ejection method executed by the liquid ejection device 100 drives so that the connection interval T2 satisfies formula (1) or (2). According to this method, the influence of residual vibration due to the micro-vibration of the meniscus MN caused by the application of the non-ejection pulse is suppressed from affecting the ejection of ink immediately after the micro-vibration. Therefore, the ejection of ink after the micro-vibration is suppressed from becoming unstable. Therefore, deterioration of image quality can be suppressed.

[0146] In addition, when either the connection interval T2 or the pulse interval T1 of the first embodiment satisfies formula (1) or formula (2), the ink ejection after the micro-vibration is prevented from becoming unstable. Furthermore, when both the connection interval T2 and the pulse interval T1 satisfy formula (1) or formula (2), the ink ejection after the micro-vibration is prevented from becoming unstable particularly effectively.

[0147] 3. Variations Each of the above-mentioned exemplary embodiments may be modified in various ways. Specific modified embodiments that may be applied to each of the above-mentioned embodiments are illustrated below. Two or more embodiments selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0148] 3A. First Variation Fig. 26 is a diagram for explaining the drive signal Com in the first modified example. As shown in Fig. 26, the change signal CNG includes a pulse PlsC for dividing the cycle Tu into a preceding control period Tu1 and a following control period Tu2. The control period Tu1 is, for example, a period from the rising edge of the pulse PlsL to the rising edge of the pulse PlsC. The control period Tu2 is, for example, a period from the rising edge of the pulse PlsC to the rising edge of the pulse PlsL.

[0149] 26, the first drive signal Com-A has an ejection pulse P1 and a non-ejection pulse P01. The ejection pulse P1 is provided in the control period Tu2. The non-ejection pulse P01 is provided in the control period Tu1. In the first modified example, the ejection pulse and the non-ejection pulse are included in one signal.

[0150] 26, the second drive signal Com-B includes an ejection pulse P3. The ejection pulse P3 is a pulse whose potential changes so as to cause a pressure fluctuation in the pressure chamber C so that the pressure generating means 51e ejects ink from the nozzle N. By supplying the ejection pulse P3 to the pressure generating means 51e, ink is ejected as an ink droplet from the nozzle N.

[0151] The ejection pulse P3 includes a second expansion driving element v1, a minimum potential v2, a contraction driving element v3, a high potential v4, an expansion driving element v5, a low potential v6, a contraction driving element v7, a maximum potential v8, and an expansion driving element v9, in this order. The minimum potential v2 is the minimum value of the voltage of the ejection pulse P3. The maximum potential v8 is the maximum value of the voltage of the ejection pulse P3. The high potential v4 is a potential higher than the reference potential and lower than the maximum potential v8. The low potential v6 is a potential lower than the reference potential and higher than the minimum potential v2. The second expansion driving element v1 is a falling edge from the reference potential to the minimum potential v2. The second expansion driving element v1 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The contraction driving element v3 is a rising edge from the minimum potential v2 to the high potential v4. The contraction driving element v3 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The expansion driving element v5 is a falling edge going from high potential v4 to low potential v6. The expansion driving element v5 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The contraction driving element v7 is a rising edge going from low potential v6 to maximum potential v8. The contraction driving element v7 is a driving element that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The expansion driving element v9 is a falling edge going back from maximum potential v8 to the reference potential. The expansion driving element v9 is a driving element that drives the pressure generating means 51e to expand the volume of the pressure chamber C.

[0152] In FIG. 26, the third drive signal Com-C includes a non-ejection pulse P02.

[0153] The driving signal generating unit 24 repeatedly generates the driving signal Com including a plurality of pulses such as the above-mentioned ejection pulse P1, ejection pulse P3, non-ejection pulses P01 and P02. The ejection pulse P1, ejection pulse P3, non-ejection pulses P01 and P02 are appropriately selected and used for the supply signal Vin. The driving signal Com shown in FIG. 26 may include pulses other than the ejection pulse P1, ejection pulse P3, non-ejection pulses P01 and P02. For example, the non-ejection pulses P03 and P04 described in each of the above-mentioned embodiments may be included.

[0154] Fig. 27 is a diagram showing the pulse interval T1 and connection interval T2 between the non-ejection pulse P01 and the ejection pulse P3. Fig. 28 is a diagram showing the pulse interval T1 and connection interval T2 between the non-ejection pulse P02 and the ejection pulse P3. Fig. 27 shows an example in which the non-ejection pulse P01 is selected in the preceding period Tua, and the ejection pulse P3 is selected in the following period Tub. Fig. 28 shows an example in which the non-ejection pulse P02 is selected in the preceding period Tua, and the ejection pulse P3 is selected in the following period Tub.

[0155] Each of the non-ejection pulses P01 and P02 initially includes a first expansion drive element a1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The ejection pulse P3 initially includes a second expansion drive element v1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first expansion drive element a1 and the second expansion drive element v1 are in phase.

[0156] The pulse interval T1 between the preceding non-ejection pulse P01 or P02 of the cycle Tua and the following ejection pulse P3 of the cycle Tub satisfies the above-mentioned formula (1). That is, when the first driving element of the non-ejection pulse is the first expansion driving element a1 and the first driving element of the ejection pulse is the second expansion driving element v1, the pulse interval T1 satisfies formula (1). When the pulse interval T1 satisfies formula (1), the ejection of ink after micro-vibration is prevented from becoming unstable, compared to when formula (1) is not satisfied. Therefore, deterioration in image quality can be suppressed.

[0157] 27 and 28, the pulse interval T1 is the time interval between the half-value point A1 of the period of the first expansion driving element a1 of the non-ejection pulse P01 or P02 and the half-value point S1 of the period of the second expansion driving element v1 of the ejection pulse P3. The half-value point V1 is a value that is 50% increased from the minimum potential v2 of the second expansion driving element v1.

[0158] Moreover, each of the non-ejection pulses P01 and P02 includes at the end a first contraction driving element a3 that drives the pressure generating means 51e to contract the volume of the pressure chamber C. The ejection pulse P3 includes at the beginning a second expansion driving element v1 that drives the pressure generating means 51e to expand the volume of the pressure chamber C. The first contraction driving element a3 and the second expansion driving element v1 are in opposite phase.

[0159] The connection interval T2 between the non-ejection pulse P01 or P02 of the preceding cycle Tua and the ejection pulse P3 of the following cycle Tub satisfies the above-mentioned formula (2). That is, when the last driving element of the non-ejection pulse is the first contraction driving element a3 and the first driving element of the ejection pulse is the second expansion driving element v1, the connection interval T2 satisfies formula (2).

[0160] When the connection interval T2 satisfies formula (2), the ink ejection after the micro-vibration is prevented from becoming unstable, compared to when the connection interval T2 does not satisfy formula (2). In Figures 27 and 28, the connection interval T2 is the time interval between the half-value point A2 of the period of the first contraction driving element a3 of the non-ejection pulse P01 or P02 and the half-value point V1 of the period of the second expansion driving element v1 of the ejection pulse P3.

[0161] In the first modified example, the case where both the pulse interval T1 and the connection interval T2 satisfy the formula (1) or (2) has been described as an example. However, if either one of the pulse interval T1 and the connection interval T2 satisfies the formula (1) or (2), it is possible to prevent the ink ejection after the micro-vibration from becoming unstable.

[0162] In addition, in the first variant, based on the change signal CNG shown in FIG. 26, as shown in FIG. 8 and FIG. 9, a non-ejection pulse P01 or P02 may be selected in the preceding period Tua, and an ejection pulse P1 may be selected in the following period Tub.

[0163] 3B. Second Variation Fig. 29 is a diagram for explaining the drive signal Com in the second modified example. In Fig. 29, the first drive signal Com-A has an ejection pulse P1, and the second drive signal Com-B includes an ejection pulse P3. Also, in Fig. 29, the third drive signal Com-C includes non-ejection pulses P01 and P2. The non-ejection pulse P01 is provided in the control period Tu1. The non-ejection pulse P02 is provided in the control period Tu2. In the second modified example, a single signal includes multiple non-ejection pulses.

[0164] In this modified example, for example, a non-ejection pulse P01 or P02 may be selected in the preceding period Tua and an ejection pulse P1 may be selected in the following period Tub based on the change signal CNG, as shown in Figures 8 and 9. Also, for example, a non-ejection pulse P01 or P02 may be selected in the preceding period Tua and an ejection pulse P3 may be selected in the following period Tub, as shown in Figures 27 and 28.

[0165] 3C. Third Variation Fig. 30 is a schematic diagram for explaining the circulation flow path of a liquid ejection head 50B of a third modified example. The liquid ejection head 50B is similar to the liquid ejection head 50 of the first embodiment described above, except that the liquid ejection head 50B has a plurality of individual flow paths IPa and a plurality of individual flow paths IPb instead of the plurality of individual flow paths IP. That is, as shown in Fig. 30, the liquid ejection head 50B is provided with a plurality of nozzles N, a plurality of individual flow paths IPa, a plurality of individual flow paths IPb, a first common liquid chamber R1, and a second common liquid chamber R2, and is connected to a circulation mechanism 60.

[0166] More specifically, the liquid ejection head 50B is provided with a plurality of nozzles Na and a plurality of nozzles Nb. Each of these nozzles is configured similarly to the nozzle N in the above-described embodiment, and ejects ink in the Z2 direction. In the following description, when there is no need to distinguish between the nozzles Na and Nb, they will simply be referred to as "nozzles N."

[0167] The multiple nozzles Na are arranged along the Y axis, and a group of these constitute a first nozzle row La. Similarly, the multiple nozzles Nb are arranged along the Y axis, and a group of these constitute a second nozzle row Lb.

[0168] The first nozzle row La and the second nozzle row Lb are aligned at a predetermined interval along the X-axis. Here, the arrangement pitch of the nozzles Na and the arrangement pitch of the nozzles Nb are equal to each other, but the nozzles Na and the nozzles Nb that are closest to each other are shifted from each other in the Y-axis direction.

[0169] An individual flow path IPa communicates with each of the multiple nozzles Na. Each of the multiple individual flow paths IPa extends along the X-axis and communicates with a different nozzle Na from the other. Similarly, an individual flow path IPb communicates with each of the multiple nozzles Nb. Each of the multiple individual flow paths IPb extends along the X-axis and communicates with a different nozzle Nb from the other. The individual flow paths IPa and the individual flow paths IPb are alternately arranged along the Y-axis.

[0170] The individual flow path IPa is similar to the individual flow path IP of the above embodiment, except that the pressure chamber Cb is omitted. Specifically, the individual flow path IPa includes a first flow path section Pa1 and a second flow path section Pa2. The first flow path section Pa1 in each individual flow path IPa is a flow path between an upstream end E1 of the individual flow path IPa and the nozzle Na. The first flow path section Pa1 includes a pressure chamber Ca. On the other hand, the second flow path section Pa2 in each individual flow path IPa is a flow path between a downstream end E2 of the individual flow path IPa and the nozzle Na.

[0171] The individual flow paths IPb are similar to the individual flow paths IP of the above-described embodiment, except that the pressure chamber Ca is omitted. Specifically, the individual flow paths IPb include a third flow path portion Pb1 and a fourth flow path portion Pb2. The third flow path portion Pb1 in each individual flow path IPb is a flow path between an upstream end E1 of the individual flow path IPb and the nozzle Nb. On the other hand, the fourth flow path portion Pb2 in each individual flow path IPb is a flow path between a downstream end E2 of the individual flow path IPb and the nozzle Nb. The fourth flow path portion Pb2 includes a pressure chamber Cb.

[0172] A first common liquid chamber R1 is connected to the upstream end E1 of each of the individual flow paths IPa and IPb, while a second common liquid chamber R2 is connected to the downstream end E2 of each of the individual flow paths IPa and IPb.

[0173] Fig. 31 is a cross-sectional view taken along the line A2-A2 in Fig. 30. Fig. 31 shows a cross section of the liquid ejection head 50B cut along an individual flow path IPa by a plane parallel to the X-axis and Z-axis. Below, the configuration relating to the individual flow path IPa will be representatively described. Note that the individual flow paths IPb are the same as the individual flow paths IPa except that their orientation is different by 180° around the Z-axis, and therefore description thereof will be omitted.

[0174] The individual flow paths IPa are similar to the individual flow paths IP of the first embodiment described above, except that the pressure chambers Cb are replaced with horizontal communication flow paths Cq1. The liquid ejection head 50B is configured similarly to the liquid ejection head 50 of the first embodiment described above, except that it includes a nozzle substrate 51aB, a flow path substrate 51bB, and a pressure chamber substrate 51cB instead of the nozzle substrate 51a, the flow path substrate 51b, and the pressure chamber substrate 51c. Note that in the individual flow paths IPa, the pressure generating means 51e corresponding to the pressure chambers Cb is omitted.

[0175] The nozzle substrate 51aB is provided with a plurality of nozzles Na. The nozzle substrate 51aB is configured similarly to the nozzle substrate 51a described above, except for the arrangement of the nozzles Na. When viewed in the direction along the Z axis, the nozzles Na overlap the pressure chambers Ca.

[0176] The flow path substrate 51bB is provided with the above-mentioned individual flow paths IPa except for the pressure chambers Ca, the liquid chambers R1a and the liquid chambers R2a.

[0177] As shown in Fig. 31, each individual flow path IPa has a communication flow path Nf, a horizontal communication flow path Cq1, an individual supply flow path Ra1, and an individual discharge flow path Ra2 in addition to the pressure chamber Ca. Of these, the communication flow path Nf, the horizontal communication flow path Cq1, the individual supply flow path Ra1, and the individual discharge flow path Ra2 are provided in the flow path substrate 51bB. Here, the first communication flow path Na1 of the communication flow path Nf overlaps with the nozzle Na when viewed in the direction along the Z axis. In addition, the nozzle Na branches off from the first communication flow path Na1 in a direction different from the nozzle flow path Nfa.

[0178] The lateral communication channel Cq1 is a space extending along the X-axis. The lateral communication channel Cq1 communicates the second communication channel Na2 with the individual discharge channel Ra2, and guides ink from the second communication channel Na2 to the individual discharge channel Ra2.

[0179] The pressure chamber substrate 51cB is similar to the pressure chamber substrate 51c of the above-described embodiment, except that the pressure chamber Cb is omitted for the individual flow passage IPa.

[0180] 3D.Other Variations Although the above-described embodiments and modified examples are provided with a circulation mechanism, the circulation mechanism does not necessarily have to be provided. However, by providing a circulation mechanism, even if the micro-vibration of the meniscus MN is increased so that the ink circulating through the circulation flow path can be efficiently replaced with the ink in the nozzle N, the stability of the ejection of ink droplets immediately after the micro-vibration can be ensured.

[0181] In the above-mentioned embodiments, two types of ejection pulses P1 and P2 or ejection pulses P1 and P3 are exemplified, but the ejection pulses are not limited to these and may be pulses of other shapes. Similarly, in the above-mentioned embodiments, four types of non-ejection pulses P01, P02, P03, and P04 are exemplified, but the non-ejection pulses are not limited to these and may be pulses of other shapes. In addition, in the above-mentioned embodiments, four types of non-ejection pulses P01, P02, P03, and P04 are exemplified, but the non-ejection pulse may be at least one.

[0182] In each of the above-described embodiments, the nozzle N has a first portion NP1 and a second portion NP2, but the nozzle N is not limited to this configuration. For example, the nozzle N may have a constant width or may have a shape with three or more steps.

[0183] The pressure generating means for generating pressure fluctuations in the ink in the pressure chamber C is not limited to the pressure generating means 51e exemplified in each of the above-described embodiments. For example, a heating element that generates air bubbles in the pressure chamber C by applying heat to cause fluctuations in the ink pressure may be used as the pressure generating means.

[0184] In each of the above-described embodiments, a serial-type liquid ejection device 100 in which a carriage 41 carrying a liquid ejection head 50 is moved back and forth has been exemplified, but the present disclosure can also be applied to a line-type liquid ejection device in which multiple nozzles N are distributed across the entire width of the medium M.

[0185] The liquid ejection device 100 exemplified in the above embodiment may be adopted in various devices such as facsimile machines and copy machines in addition to devices dedicated to printing, and the use of the present disclosure is not particularly limited. However, the use of the liquid ejection device is not limited to printing. For example, a liquid ejection device that ejects a solution of a color material is used as a manufacturing device that forms a color filter of a display device such as a liquid crystal display panel. In addition, a liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device that forms wiring and electrodes of a wiring board. In addition, a liquid ejection device that ejects a solution of an organic substance related to a living body is used as a manufacturing device that manufactures, for example, a biochip.

[0186] Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above embodiment. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above embodiment, and any configuration can be added. [Explanation of symbols]

[0187] 50...liquid ejection head, 51e...pressure generating means, 100...liquid ejection device, 510...ejection section, C...pressure chamber, Com...driving signal, IP...individual flow path, Img...printing data, MN...meniscus, N...nozzle, P01, P02, P03, P04...non-ejection pulse, P1, P2, P3...ejection pulse, T1...pulse interval, T2...connection interval, T3...pulse width, Tc...natural vibration period, Tu...period, Vm...ink droplet velocity, a1...first expansion drive element, a3...first contraction drive element, b1...first contraction drive element, b3...first expansion drive element, s1...second expansion drive element, u1...preparatory contraction drive element, v1...second expansion drive element.

Claims

1. a discharge section including a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating pressure fluctuations in liquid within the pressure chamber; a drive signal generating unit that repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse; a drive control unit that supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, the ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to eject liquid from the nozzle, the non-ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to cause the pressure fluctuation so that liquid is not ejected from the nozzle, When the non-ejection pulse is selected in a preceding cycle and the ejection pulse is selected in a succeeding cycle of two consecutive cycles among the repeating cycles, A pulse interval T1 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies either of the following formulas (1) and (2): A liquid ejection device comprising: 1.7×Tc×n≦T1≦1.9×Tc×n (1) 1.2×Tc×n≦T1≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

2. the non-ejection pulse first includes a first expansion drive element that drives the pressure generating means to expand the volume of the pressure chamber; the ejection pulse first includes a second expansion drive element that drives the pressure generating means to expand the volume of the pressure chamber; The pulse interval T1 satisfies the formula (1). The liquid ejection device according to claim 1 .

3. the non-ejection pulse first includes a first expansion driving element that drives the pressure generating means to expand the volume of the pressure chamber; the ejection pulse initially includes a preparatory contraction drive element that drives the pressure generating means to contract the volume of the pressure chamber; The pulse interval T1 satisfies the formula (2). The liquid ejection device according to claim 1 .

4. the non-ejection pulse initially includes a first contraction drive element that drives the pressure generating means to contract a volume of the pressure chamber; the ejection pulse first includes a second expansion drive element that drives the pressure generating means to expand the volume of the pressure chamber; The pulse interval T1 satisfies the formula (2). The liquid ejection device according to claim 1 .

5. the non-ejection pulse first includes a first contraction driving element that drives the pressure generating means to contract the volume of the pressure chamber; the ejection pulse initially includes a preparatory contraction drive element that drives the pressure generating means to contract the volume of the pressure chamber; The pulse interval T1 satisfies the formula (1). The liquid ejection device according to claim 1 .

6. The n is 1. The liquid ejection device according to claim 1 .

7. The pulse width T3 of the non-ejection pulse is 0.5Tc. The liquid ejection device according to claim 1 .

8. a discharge section including a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating pressure fluctuations in liquid within the pressure chamber; a drive signal generating unit that repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse; a drive control unit that supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, the ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to eject liquid from the nozzle, the non-ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to cause the pressure fluctuation so that liquid is not ejected from the nozzle, When the non-ejection pulse is selected in a preceding cycle and the ejection pulse is selected in a succeeding cycle of two consecutive cycles among the repeating cycles, A connection interval T2 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies either of the following formulas (1) and (2): A liquid ejection device comprising: 1.7×Tc×n≦T2≦1.9×Tc×n (1) 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

9. the non-ejection pulse finally includes a first contraction driving element that drives the pressure generating means to contract the volume of the pressure chamber; the ejection pulse first includes a second expansion drive element that drives the pressure generating means to expand the volume of the pressure chamber; The connection interval T2 satisfies the above formula (2). The liquid ejection device according to claim 8.

10. the non-ejection pulse finally includes a first contraction driving element that drives the pressure generating means to contract the volume of the pressure chamber; the ejection pulse initially includes a preparatory contraction drive element that drives the pressure generating means to contract the volume of the pressure chamber; The connection interval T2 satisfies the above formula (1). The liquid ejection device according to claim 8.

11. the non-ejection pulse finally includes a first expansion driving element that drives the pressure generating means to expand the volume of the pressure chamber; the ejection pulse first includes a second expansion drive element that drives the pressure generating means to expand the volume of the pressure chamber; The connection interval T2 satisfies the above formula (1). The liquid ejection device according to claim 8.

12. the non-ejection pulse finally includes a first expansion driving element that drives the pressure generating means to expand the volume of the pressure chamber; the ejection pulse initially includes a preparatory contraction drive element that drives the pressure generating means to contract the volume of the pressure chamber; The connection interval T2 satisfies the above formula (2). The liquid ejection device according to claim 8.

13. The n is 1. The liquid ejection device according to claim 1 .

14. The pulse width T3 of the non-ejection pulse is 0.5Tc. The liquid ejection device according to claim 1 .

15. A liquid ejection method performed by a liquid ejection device capable of ejecting liquid, comprising: The liquid ejection device includes: a discharge section including a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating pressure fluctuations in liquid within the pressure chamber; a drive signal generating unit that repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse; a drive control unit that supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, the ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to eject liquid from the nozzle, the non-ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to cause the pressure fluctuation so that liquid is not ejected from the nozzle, When the non-ejection pulse is selected in a preceding cycle and the ejection pulse is selected in a succeeding cycle of two consecutive cycles among the repeating cycles, A pulse interval T1 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies either of the following formulas (1) and (2): A liquid ejection method comprising: 1.7×Tc×n≦T1≦1.9×Tc×n (1) 1.2×Tc×n≦T1≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

16. A liquid ejection method performed by a liquid ejection device capable of ejecting liquid, comprising: The liquid ejection device includes: a discharge section including a nozzle, a pressure chamber communicating with the nozzle, and a pressure generating means for generating pressure fluctuations in liquid within the pressure chamber; a drive signal generating unit that repeatedly generates a drive signal including a plurality of pulses including an ejection pulse and a non-ejection pulse; a drive control unit that supplies a pulse selected from the ejection pulse and the non-ejection pulse included in the drive signal to the pressure generating means for each repeating period, the ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to eject liquid from the nozzle, the non-ejection pulse is a pulse whose potential changes so as to cause the pressure generating means to cause the pressure fluctuation so that liquid is not ejected from the nozzle, When the non-ejection pulse is selected in a preceding cycle and the ejection pulse is selected in a succeeding cycle of two consecutive cycles among the repeating cycles, A connection interval T2 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies either of the following formulas (1) and (2): A liquid ejection device comprising: 1.7×Tc×n≦T2≦1.9×Tc×n (1) 1.2×Tc×n≦T2≦1.4×Tc×n (2) The natural vibration period of the ejection portion is denoted by Tc, and n is a natural number.

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