JP2005280199A - Liquid jet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the degree of freedom of setting slight vibrations to suppress the thickening of a liquid in nozzle openings and increase the speed of good liquid drop discharge. <P>SOLUTION: A slight vibration pulse PV includes a slight vibration main element Pa having a slight vibration expansion element P1 to expand a pressure chamber 38 to a volumetric capacity larger than a reference volumetric capacity to the extent that ink drops are prevented from getting discharged and a slight vibration contraction element P3 to contract the pressure chamber 38 to a volumetric capacity smaller than the reference volumetric capacity to the extent that ink drops are prevented from getting discharged and a slight vibration attenuating element Pb to causing the pressure chamber 38 to restore the reference volumetric capacity, and converges the slight vibrations of a meniscus generated before supply of a discharge pulse PS by arranging the slight vibration braking element Pb behind the slight vibration main element Pa. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid ejecting apparatus capable of controlling the discharge of droplets from nozzle openings by controlling the supply of drive pulses to pressure generating elements.

  The liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting liquid as droplets and ejects various liquids from the liquid ejecting head. As a typical example of this liquid ejecting apparatus, for example, image recording such as an ink jet printer that performs recording by ejecting (jetting) liquid ink onto a recording paper or the like as an object to form dots. A device can be mentioned. In recent years, it is applied not only to this image recording apparatus but also to various manufacturing apparatuses. For example, in a display manufacturing apparatus such as a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, or an FED (surface emitting display), various liquid materials such as coloring materials and electrodes are used for pixel formation regions and electrode formation. A liquid ejecting apparatus is used for discharging to an area or the like.

  Here, taking the ink jet printer (hereinafter simply abbreviated as “printer”) as an example, this printer includes a nozzle opening communicating with the pressure chamber, and a pressure generating element capable of causing pressure fluctuation in ink in the pressure chamber. And a drive signal generation circuit that generates a drive signal including a drive pulse. The pressure generation element is operated by supplying the drive pulse to the pressure generation element, and ink is dropped from the nozzle opening. It is comprised so that it may discharge.

For such a printer, the drive pulse includes an ejection pulse for ejecting ink, and a fine vibration pulse for causing the meniscus of the nozzle opening (the free surface of the ink exposed at the nozzle opening) to vibrate to such an extent that the ink is not ejected. There has been proposed one including the above (see, for example, Patent Document 1). This slight vibration pulse causes, for example, a problem that the meniscus is slightly vibrated during the non-ejection period when ink is not ejected to convect the ink between the nozzle opening and the pressure chamber, and the ink at the nozzle opening is thickened during the non-ejection period. Is preventing. Therefore, even when the non-ejection period is long (specifically, when intermittent printing is performed after printing a plurality of blank lines), it is easy to maintain the flight stability of the ink droplets ejected from the nozzle openings. .
JP 2000-37867 A

  By the way, in order for the micro-vibration pulse to exhibit the effect of preventing ink thickening, the micro-vibration driving voltage Vhv (difference between the maximum potential and the minimum potential in the micro-vibration pulse PV) shown in FIG. It is necessary to set it to such an extent that the above-described ink convection is sufficiently caused. This setting includes, for example, the supply time t of the fine vibration pulse PV and the fine vibration level (fine vibration drive voltage Vhv and discharge drive voltage Vhs (the highest potential and the lowest potential in the discharge pulse PS) at which a good print result is obtained in intermittent printing. (The difference with the potential))) (the solid line L0 in FIG. 7B). In an actual printer, a slight vibration level that is slightly higher than the value indicated by the solid line in FIG.

  However, when using ink that tends to thicken or ink with high viscosity as the liquid to be ejected, it is necessary to further increase the micro-vibration driving voltage to sufficiently generate micro-vibration of the meniscus. However, if the fine vibration drive voltage is set too high, the upper limit L1 (value indicated by the broken line in FIG. 7B) that can maintain the continuous print stability is exceeded, and the continuous print stability is increased. The fine vibration level setting range (indicated by the hatched portion in the figure) that satisfies the performance and intermittent print evaluation. That is, the ejection pulse is supplied before the fine vibration of the meniscus converges, and the meniscus vibration during ink ejection is not performed as designed, and there is a possibility that a good printing result cannot be obtained.

  Therefore, in order to obtain a good printing result, it is necessary to sufficiently converge the fine vibration to suppress the influence on the droplet discharge. For that purpose, the fine vibration pulse supply time is set long (that is, the fine vibration) The pulse potential gradient must be made gentle), or the time from the end of the minute vibration pulse to the start of the ejection pulse must be set longer. Therefore, it is difficult to increase the printing speed when using high viscosity ink. In addition, the selection range of the fine vibration level is narrowly limited, and it is difficult to increase the degree of freedom in setting the printing operation.

  Further, when the supply time of the fine vibration pulse is set to a short time, there is no fine vibration level setting range that satisfies the continuous print stability and the intermittent print evaluation as shown in FIG. 7B. For this reason, it is difficult to select the supply of the micro-vibration pulse for a short time, and it is difficult to shorten the time required for good printing (droplet discharge).

  The present invention has been made in view of such circumstances, and an object of the present invention is to increase the degree of freedom of setting a fine vibration that suppresses the thickening of the liquid at the nozzle opening, and to speed up the good droplet discharge. Is to be able to.

The liquid ejecting apparatus of the present invention has been proposed to achieve the above object, and includes a nozzle opening communicating with a pressure chamber and a pressure generating element capable of causing pressure fluctuation in the liquid in the pressure chamber. Driving signal generating means for generating a driving signal including a driving pulse,
The drive pulse includes a discharge pulse for discharging a droplet and a fine vibration pulse for finely vibrating the meniscus of the nozzle opening to the extent that the droplet is not discharged.
A liquid ejecting apparatus capable of operating a pressure generating element by supplying a driving pulse to a pressure generating element and discharging a droplet from a nozzle opening,
The micro-vibration pulse includes a micro-vibration expansion element that expands the pressure chamber from the reference volume to such an extent that no droplet is ejected, and a micro-vibration contraction element that contracts the pressure chamber from the reference volume to an extent that no droplet is ejected. A fine vibration main element, and a fine vibration damping element for returning the pressure chamber to the reference volume,
By disposing the fine vibration damping element after the fine vibration main element, the fine vibration of the meniscus generated before supplying the ejection pulse is converged.

  In the above configuration, it is desirable that the fine vibration damping element is arranged before the next ejection pulse.

  Further, in the above configuration, the micro-vibration pulse includes a micro-vibration expansion element that expands the pressure chamber from the reference volume to such an extent that no droplet is ejected, and micro-vibration contraction that contracts the pressure chamber expanded by the micro-vibration expansion element. It is desirable that the fine vibration main element including the element and the fine vibration damping element for returning the pressure chamber contracted by the fine vibration contraction element to the reference volume are restored.

  According to the above configuration, by arranging the fine vibration damping element after the fine vibration main element, the fine vibration of the meniscus generated before the supply of the discharge pulse is converged, so that the pressure generating element is driven by the fine vibration pulse. Even if the pressure is increased, it is possible to prevent a problem that the fine vibration of the meniscus is added to the vibration of the meniscus due to the ejection pulse. Accordingly, it is possible to increase the degree of freedom in setting the fine vibration. In addition, the fine vibration of the meniscus can be quickly converged, and good droplet ejection speed can be achieved. Furthermore, even for highly viscous or easily thickened liquids, it is possible to suppress the increase in viscosity at the nozzle opening and to prevent inconveniences in which microvibration of the meniscus affects droplet ejection, thus realizing excellent droplet ejection. be able to.

  In addition, if the fine vibration damping element is arranged before the next discharge pulse, the liquid droplet can be discharged after the fine vibration of the meniscus is always converged. It is easier to prevent.

  The micro-vibration pulse includes a micro-vibration expansion element that expands the pressure chamber beyond the reference volume to the extent that no droplet is ejected, and a micro-vibration contraction element that contracts the pressure chamber expanded by the micro-vibration expansion element. Consists of a main vibration element and a fine vibration damping element that expands and restores the pressure chamber contracted by the fine vibration contraction element to the reference volume. Therefore, there is no possibility that droplets are ejected when the fine vibration damping element is supplied.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In the following, an ink jet printer (hereinafter abbreviated as printer 1) will be exemplified as an example of the liquid ejecting apparatus of the invention. FIG. 1 is a functional block diagram of the printer 1.

  As shown in FIG. 1, the printer 1 is schematically configured by a printer controller 2 and a print engine 3. The printer controller 2 includes an external interface (external I / F) 4 that receives print data from an external device such as a host computer (not shown), a RAM 5 that stores various data, and the like for various data processing. ROM 6 that stores the control routine, a control unit 7 including a CPU, an oscillation circuit 8, and a drive signal generation circuit 10 that generates a drive signal to be supplied to a recording head 9 described later (drive signal generation means in the present invention) And an internal interface (internal I / F) 11 for outputting ejection data, drive signals, and the like obtained by developing (data converting) the print data for each dot to the print engine 3. Yes.

  The control unit 7 controls each unit of the printer 1 according to an operation program or the like stored in the ROM 6. Further, the control unit 7 converts print data input from an external device via the external interface 4 into discharge data used for discharging ink droplets in the recording head 9.

  The drive signal generation circuit 10 is a circuit that generates a drive signal having a waveform shape determined by the control unit 7. The drive signal generation circuit 10 includes, for example, a drive signal including a plurality of ejection pulses and a drive pulse configured by arranging fine vibration pulses for finely vibrating the meniscus during non-recording as shown in FIG. And the drive signal is supplied to the recording head 9 via the internal I / F 11. The drive pulse (drive signal) generated by the drive signal generation circuit 10 will be described in detail later.

  The print engine 3 includes a recording head 9, a carriage moving mechanism 14 that moves a carriage to which the recording head 9 is detachably attached in the paper width direction (main scanning direction) of the recording paper, and a direction orthogonal to the moving direction of the recording head 9. And a paper feed mechanism 15 that conveys the recording paper in the paper feed direction (sub-scanning direction). The recording head 9 is a kind of the liquid jet head according to the present invention, and includes a shift register (SR) 16 in which print data is set, a latch circuit 17 that latches the print data set in the shift register 16, and a voltage amplifier. A level shifter 18 that functions, a piezoelectric vibrator 19, and a switch circuit 20 that controls supply of a drive signal to the piezoelectric vibrator 19 are provided.

  Here, the structure of the recording head 9 will be described. The recording head 9 is configured to be able to eject liquid ink (a kind of liquid in the present invention) from the nozzle opening 25 as ink droplets in a moving state in the main scanning direction by the carriage moving mechanism 14. As shown in FIG. 2, the recording head 9 includes a vibrator unit 28 in which a plurality of piezoelectric vibrators 19, a fixed plate 26, a flexible cable 27, and the like are unitized, and a case in which the vibrator unit 28 can be stored. 29 and a flow path unit 30 joined to the front end surface of the case 29.

  The case 29 is a synthetic resin block-like member in which a housing empty portion 31 having both the front end and the rear end opened, and the vibrator unit 28 is housed and fixed in the housing empty portion 31.

The piezoelectric vibrator 19 is a kind of pressure generating element according to the present invention, and is formed in a comb-teeth shape elongated in the vertical direction. The piezoelectric vibrator 19 is a laminated piezoelectric vibrator configured by alternately laminating piezoelectric bodies and internal electrodes, and is a longitudinal vibration mode piezoelectric vibrator capable of expanding and contracting in a vertical direction perpendicular to the stacking direction. It is. The front end surface of each piezoelectric vibrator 19 is joined to the island portion 32 of the flow path unit 30.
The piezoelectric vibrator 19 behaves like a capacitor. That is, when the signal supply is stopped, the potential of the piezoelectric vibrator 19 (vibrator potential) is held at the potential immediately before the stop.

  In the flow path unit 30, the nozzle plate 34 is disposed on one surface side of the flow path formation substrate 33 with the flow path formation substrate 33 interposed therebetween, and the elastic plate 35 is disposed on the other surface opposite to the nozzle plate 34. It is configured by arranging and laminating on the side.

  The nozzle plate 34 is composed of a thin metal plate material (for example, a stainless steel plate) in which a plurality of (for example, 180) nozzle openings 25 are opened along the sub-scanning direction. The flow path forming substrate 33 is a plate-like member in which an ink flow path including a common ink chamber 36, an ink supply port 37, a pressure chamber 38, and a nozzle communication port 39 is formed. In the present embodiment, the flow path forming substrate 33 is produced by etching a silicon wafer. The elastic plate 35 is a double-structured composite plate material obtained by laminating a resin film 41 on a stainless steel support plate 40. The portion of the support plate 40 corresponding to the pressure chamber 38 is annularly removed to form the island portion 32. Forming.

  In the recording head 9, a series of ink flow paths from the common ink chamber 36 to the nozzle opening 25 through the pressure chamber 38 is formed for each nozzle opening 25. The piezoelectric vibrator 19 is deformed by charging or discharging the piezoelectric vibrator 19. That is, the piezoelectric vibrator 19 in the longitudinal vibration mode contracts in the longitudinal direction of the vibrator by charging and expands in the longitudinal direction of the vibrator by discharging. Therefore, when the vibrator potential is increased by charging, the island portion 32 is pulled toward the piezoelectric vibrator 19 side, the resin film 41 around the island portion 32 is deformed, and the pressure chamber 38 is expanded. Further, when the vibrator potential is lowered by the discharge, the pressure chamber 38 contracts.

  Thus, since the volume of the pressure chamber 38 can be controlled according to the vibrator potential, the ink pressure in the pressure chamber 38 can be varied, and ink droplets can be ejected from the nozzle openings 25. For example, ink droplets can be ejected by expanding the reference volume pressure chamber 38 once and then rapidly contracting it. In addition, the fine vibration of the meniscus exposed to the nozzle opening 25 can be generated.

  Next, the drive pulse DP included in the drive signal generated by the drive signal generation circuit 10 will be described. The drive pulse DP illustrated in FIG. 3 includes a fine vibration pulse PV, a plurality of (three in the present embodiment) ejection pulses PS, and a connection element PC that connects the pulses and is not supplied to the piezoelectric vibrator 19. It is configured. The fine vibration pulse PV is a pulse for causing fine vibration in printing. As shown in FIG. 3B, the fine vibration main element Pa for generating a fine vibration in the meniscus of the nozzle opening 25, and the fine vibration. And a fine vibration damping element Pb for converging the fine vibration generated by the main element Pa. The fine vibration damping element Pb is disposed after the fine vibration main element Pa.

  The micro-vibration main element Pa applies a potential for a predetermined time (for example, 4 μs) with a relatively gentle potential gradient that does not eject ink droplets from the intermediate potential (reference potential) VM to the micro-vibration potential VMH that is higher than the intermediate potential VM. The fine vibration expansion element P1 to be raised, the fine vibration hold element P2 that is generated following the fine vibration expansion element P1 and maintains the fine vibration potential VMH for a predetermined time (for example, 1 μs), and the fine vibration hold element P2 are generated. And a minute vibration contraction element P3 that lowers the potential for a predetermined time (for example, 8 μs) with a relatively gentle potential gradient that does not eject ink droplets from the minute vibration potential VMH to the lowest potential VG lower than the intermediate potential VM. Has been. The fine vibration damping element Pb is an element that increases the potential for a predetermined time (for example, 3 μs) with a relatively gentle potential gradient from the lowest potential VG to the intermediate potential VM. Note that the micro-vibration driving voltage applied to generate micro-vibration in the meniscus is expressed by a potential difference Vhv between the micro-vibration potential VMH and the lowest potential VG.

  Between the fine vibration main element Pa and the fine vibration damping element Pb, a connection element P4 that connects the two elements while maintaining a constant potential (minimum potential VG) is disposed. This connection element P4 is generated following the micro-vibration contraction element P3, and also functions as a hold element that maintains the minimum potential VG for a predetermined time (for example, 1 μs).

  The ejection pulse PS is a pulse for ejecting ink droplets from the nozzle openings 25. This ejection pulse PS follows the first expansion element P11 and the first expansion element P11 that increase the potential with a constant gradient that does not cause ink droplets to be ejected from the intermediate potential VM to the highest potential VP higher than the micro-vibration potential VMH. An expansion hold element P12 that is generated and maintains the maximum potential VP for a predetermined time, a discharge element P13 that is generated subsequent to the expansion hold element P12 and rapidly decreases the potential from the maximum potential VP to the minimum potential VG, and the discharge element P13. Subsequently, the discharge hold element P14 that is generated and maintains the minimum potential VG for a very short time, and the discharge hold element P14 that is generated subsequent to the minimum potential VG to the sub intermediate potential (potential slightly lower than the intermediate potential VM) VML. A first expansion return element P15 that slightly increases the potential, and an expansion return hold element P that maintains the sub intermediate potential VML for a predetermined time. 6, is constituted by a second expansion return element P17 for returning the potential from the secondary intermediate potential VML to the intermediate potential VM. Note that the ejection drive voltage applied to eject ink droplets is expressed by a potential difference Vhs between the highest potential VP and the lowest potential VG.

  When the micro-vibration pulse PV is supplied to the piezoelectric vibrator 19 among the drive pulses DP having such a configuration, the piezoelectric vibrator 19 and the pressure chamber 38 operate as follows. That is, the piezoelectric vibrator 19 slightly contracts with the supply of the micro-vibration expansion element P1, and the pressure chamber 38 starts from the reference volume (in this embodiment, the volume of the pressure chamber 38 in a steady state where no drive signal is supplied). Swells a little. Along with this expansion, the inside of the pressure chamber 38 is depressurized, and the meniscus is slightly pulled to the pressure chamber 38 side. The expansion state of the pressure chamber 38 is maintained over the supply period of the fine vibration hold element P2, and the meniscus vibrates freely during the maintenance period.

  Thereafter, the fine vibration contraction element P3 is supplied, the piezoelectric vibrator 19 expands, and the pressure chamber 38 contracts slightly from the reference volume. Along with this contraction, the ink in the pressure chamber 38 is slightly pressurized and the vibration of the meniscus is vibrated. As a result, the ink in the vicinity of the nozzle opening 25 convects and thickening is prevented. The contracted state of the pressure chamber 38 is maintained over the supply period of the connecting element P4, and the meniscus vibrates freely during the maintenance period. The fine vibration damping element Pb is supplied at a timing at which the fine vibration of the meniscus can be canceled, the piezoelectric vibrator 19 contracts again, and the pressure chamber 38 expands and returns to the reference volume. As the expansion returns, the ink in the pressure chamber 38 is slightly decompressed. Thereby, the fine vibration of the meniscus can be converged in a short time. At this time, the meniscus can converge the fine vibration while retreating from the state of being advanced in the nozzle opening 25, and there is no possibility of ejecting ink droplets.

  When the ejection pulse PS is supplied to the piezoelectric vibrator 19 subsequent to the connection element PC after the fine vibration pulse PV is supplied, the piezoelectric vibrator 19 and the pressure chamber 38 operate as follows. That is, with the supply of the first expansion element P11, the piezoelectric vibrator 19 contracts greatly, and the pressure chamber 38 expands from the steady state to the maximum volume. With this expansion, the inside of the pressure chamber 38 is depressurized, and the meniscus is drawn into the pressure chamber 38 side. The expansion state of the pressure chamber 38 is maintained over the supply period of the expansion hold element P12, and the meniscus vibrates freely during the maintenance period.

  Subsequently, the discharge element P13 is supplied, the piezoelectric vibrator 19 is greatly expanded, and the pressure chamber 38 is rapidly contracted to the minimum volume. Along with this contraction, the ink in the pressure chamber 38 is pressurized and an ink droplet is ejected from the nozzle opening 25. Then, since the discharge hold element P14 is supplied following the discharge element P13, the contracted state of the pressure chamber 38 is maintained. At this time, the meniscus is vibrated greatly due to the influence of ink droplet discharge. Thereafter, the first expansion return element P15, the expansion return hold element P16, and the second expansion return element P17 are supplied at a timing at which the meniscus vibration can be canceled, and the pressure chamber 38 is expanded and returned to the reference volume (or steady state). That is, in order to cancel out the ink pressure in the pressure chamber 38, the pressure chamber 38 is expanded to reduce the ink pressure. Thereby, the vibration of the meniscus can be suppressed in a short time, and the ejection of the next ink droplet can be stabilized.

  As described above, the fine vibration damping element Pb is arranged after the fine vibration main element Pa to form the fine vibration pulse PV, and this fine vibration pulse PV is arranged before the next ejection pulse PS so that the drive pulse DP is generated. As a result, the micro-vibration driving voltage Vhv can be set higher than that of the conventional micro-vibration pulse PV (see FIG. 7A). It can be converged in a short time before being supplied to 19. Therefore, the selection range of the micro-vibration driving voltage Vhv that satisfies the continuous printing stability can be expanded. Specifically, as shown in FIG. 4, for the fine vibration level expressed by the ratio of the fine vibration drive voltage Vhv and the ejection drive voltage Vhs, the upper limit L2 of the selection range that satisfies the continuous printing stability is set to the conventional fine vibration level. The vibration level can be raised above the upper limit L1 of the selection range that satisfies the continuous printing stability, and the degree of freedom in setting the printing operation can be increased. Further, even when ink having high viscosity or easily thickened is used, it is possible to suppress the thickening at the nozzle opening 25 and to prevent inconveniences that the fine vibration of the meniscus affects the ink droplet ejection. (As usual) ink droplet ejection can be realized.

  In addition, as the upper limit of the fine vibration level that satisfies the above-mentioned continuous printing stability is increased, the supply time in which the setting range of the fine vibration level that satisfies the continuous printing stability and the intermittent printing evaluation has not existed conventionally, That is, it is possible to select a fine vibration level at which a good printing result can be obtained even with a relatively short fine vibration pulse PV supply time. Therefore, even if the supply time t of the fine vibration pulse PV is shortened (in other words, the potential gradient of the fine vibration expansion element P1 or the fine vibration contraction element P3 is tight), the fine vibration converges before the discharge pulse PS is supplied. It is possible to prevent the ink droplet ejection vibration of the next meniscus from being disturbed by the slight vibration. Therefore, it is possible to achieve good printing speed.

  Note that the supply time and potential setting of each element of the fine vibration pulse PV may be set based on the natural vibration period of the pressure vibration of the ink and the value of the ejection drive voltage Vhs of the ejection pulse PS. In this way, the setting of the micro-vibration pulse PV can be easily adjusted in accordance with the characteristics of the recording head 9 and the characteristics of the print mode, regardless of the difference in the natural vibration period and the value of the ejection drive voltage Vhs. It is preferable that the fine vibration generated in the meniscus can be quickly converged.

  By the way, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the description of the scope of claims.

  In each of the above-described embodiments, the fine vibration pulse PV fluctuates the pressure chamber 38 in the order of expansion, contraction, and expansion return to generate the fine vibration of the meniscus of the nozzle opening 25. However, the present invention is not limited to this. Absent. That is, the fine vibration pulse PV may cause the meniscus to vibrate by changing the pressure chamber 38 in the order of contraction, expansion, and contraction return. More specifically, the fine vibration pulse PV shown in FIG. 5 constitutes the fine vibration main element Pa in the order of the fine vibration contraction element P21, the fine vibration hold element P22, and the fine vibration expansion element P23. Continuing behind Pa, the connecting element P24 and the fine vibration damping element Pb are supplied to the piezoelectric vibrator 19 in this order. First, when the fine vibration contraction element P21 is supplied to the piezoelectric vibrator 19, the piezoelectric vibrator 19 expands along with the supply, and the pressure chamber 38 contracts from the reference volume. Along with this contraction, the inside of the pressure chamber 38 is pressurized, and the meniscus is pushed out to the side opposite to the pressure chamber 38. The contraction state of the pressure chamber 38 is maintained over the supply period of the fine vibration hold element P22, and the meniscus freely vibrates over the maintenance period.

  Thereafter, the micro-vibration expansion element P23 is supplied, the piezoelectric vibrator 19 contracts, and the pressure chamber 38 expands slightly from the reference volume. Along with this expansion, the ink in the pressure chamber 38 is slightly depressurized and vibration of the meniscus is vibrated. As a result, the ink in the vicinity of the nozzle opening 25 convects and thickening is prevented. The expanded state of the pressure chamber 38 is maintained over the supply period of the connection element P24, and the meniscus vibrates freely during the maintenance period. The fine vibration damping element Pb is supplied at a timing at which the fine vibration of the meniscus can be canceled, the piezoelectric vibrator 19 expands again, and the pressure chamber 38 returns to contraction to the reference volume. Along with the restoration of the contraction, the ink in the pressure chamber 38 is slightly pressurized. Thereby, the fine vibration of the meniscus can be converged in a short time.

  In the above embodiment, the fine vibration pulse PV is arranged before the drive pulse DP, and the fine vibration of the meniscus generated before the supply of the subsequent discharge pulse PS is converged. It is not limited to this. That is, as shown in FIG. 6, the drive pulse DP may be arranged with the fine vibration pulse PV behind the ejection pulse PS. At this time, the fine vibration pulse PV can converge the fine vibration of the meniscus before the first ejection pulse PS of the next drive pulse DP is supplied.

  In each of the above embodiments, the so-called longitudinal vibration mode piezoelectric vibrator 19 is exemplified as the pressure generating element of the present invention, but the present invention is not limited to this. For example, a piezoelectric vibrator capable of vibrating in the electric field direction may be used. Moreover, it is not limited to a unit formed for each nozzle row, but may be provided for each pressure chamber, such as a so-called flexural vibration mode piezoelectric vibrator. Further, not only the piezoelectric vibrator but also other pressure generating elements such as a heating element can be used.

  The present invention can also be applied to a liquid ejecting apparatus having a liquid ejecting head other than the recording head. For example, it can be applied to a display manufacturing apparatus, an electrode manufacturing apparatus, a chip manufacturing apparatus, a micropipette, and the like.

It is a functional block diagram of an ink jet printer. FIG. 3 is a cross-sectional view illustrating a configuration of a recording head. (A) is the schematic of a drive pulse, (b) is explanatory drawing of a fine vibration pulse and an ejection pulse. It is a figure explaining the setting range of the fine vibration level which satisfies continuous printing stability and intermittent printing evaluation about the drive pulse provided with the fine vibration damping element. It is the schematic of the fine vibration pulse in 2nd Embodiment. It is the schematic of the drive pulse which has arrange | positioned the fine vibration pulse behind the discharge pulse. (A) is the schematic which shows the conventional drive pulse, (b) is a figure explaining the setting range of the fine vibration level which satisfies continuous printing stability and intermittent printing evaluation about the conventional drive pulse.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer, 2 Printer controller, 3 Print engine, 4 External interface, 5 RAM, 6 ROM, 7 Control part, 8 Oscillation circuit, 9 Recording head, 10 Drive signal generation circuit, 11 Internal interface, 14 Carriage moving mechanism, 15 Paper Feed mechanism, 16 shift register, 17 latch circuit, 18 level shifter, 19 piezoelectric vibrator, 20 switch circuit, 25 nozzle opening, 26 fixing plate, 27 flexible cable, 28 vibrator unit, 29 case, 30 flow path unit, 31 storage Empty portion, 32 islands, 33 flow path forming substrate, 34 nozzle plate, 35 elastic plate, 36 common ink chamber, 37 ink supply port, 38 pressure chamber, 39 nozzle communication port, 40 support plate, 41 resin film

Claims (3)

A nozzle opening communicating with the pressure chamber, a liquid ejecting head having a pressure generating element capable of causing a pressure fluctuation in the liquid in the pressure chamber, and a drive signal generating means for generating a drive signal including a drive pulse,
The drive pulse includes a discharge pulse for discharging a droplet and a fine vibration pulse for finely vibrating the meniscus of the nozzle opening to the extent that the droplet is not discharged.
A liquid ejecting apparatus capable of operating a pressure generating element by supplying a driving pulse to a pressure generating element and discharging a droplet from a nozzle opening,
The micro-vibration pulse includes a micro-vibration expansion element that expands the pressure chamber from the reference volume to such an extent that no droplet is ejected, and a micro-vibration contraction element that contracts the pressure chamber from the reference volume to an extent that no droplet is ejected. A fine vibration main element, and a fine vibration damping element for returning the pressure chamber to the reference volume,
A liquid ejecting apparatus characterized in that the fine vibration of the meniscus generated before the supply of the ejection pulse is converged by disposing the fine vibration damping element after the fine vibration main element.   The liquid ejecting apparatus according to claim 1, wherein the fine vibration damping element is arranged before a next ejection pulse. The micro-vibration pulse includes a micro-vibration expansion element that expands the pressure chamber from the reference volume to such an extent that droplets are not ejected, and a micro-vibration including a micro-vibration contraction element that contracts the pressure chamber expanded by the micro vibration expansion element. 3. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus includes a main element and a fine vibration damping element that expands and returns the pressure chamber contracted by the fine vibration contraction element to a reference volume.

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