JP2018089911A - Liquid jet head, liquid jet recording device and method for driving liquid jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a printing image quality by restraining a ligament length without lowering a discharge speed.SOLUTION: A liquid jet head comprises: a piezoelectric actuator having plural nozzles for jetting a liquid, and plural pressure chambers corresponding to plural nozzles, respectively filled with the liquid to change the capacity in the pressure chamber; and a control part expanding or shrinking the capacity of the pressure chamber by applying a pulse signal to the piezoelectric actuator to bring the liquid filled in the pressure chamber to jet. The control part includes a step of applying one or plural expansion pulse signals expanding the capacity in the pressure chamber, and a step of applying the shrinkage pulse signal shrinking the above capacity with a pulse width of fourth part of on-pulse peak or more but less than two times as a final application pulse signal.SELECTED DRAWING: Figure 5

Description

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

  In a liquid ejecting head such as a liquid ejecting recording apparatus, an ink column called a ligament that is stretched from a main droplet is generated during ejection from a nozzle. The ligament follows the main droplet and is stretched, and then is separated from the main droplet by the surface tension and landed, becoming a satellite or mist-like mist, which is a factor of deteriorating the print image quality. In Patent Document 1, a plurality of ink droplets are always combined during flight by adjusting the pulse width (period) of the negative voltage of the drive pulse for causing the individual ink droplets to fly, thereby achieving a target density and gradation. A technique that enables pixel formation is described.

JP 2007-210348 A

  In the prior art, in order to suppress the ligament, the discharge pressure is reduced, but there is a problem that the discharge speed of the droplets cannot be increased and the discharge cannot be performed at a higher speed.

  Therefore, the present invention has been made in view of the above circumstances, and a liquid ejecting head, a liquid ejecting recording apparatus, and the like, which can improve the printing image quality by suppressing the length of the ligament without reducing the discharge speed, It is another object of the present invention to provide a liquid jet head driving method.

  One aspect of the present invention includes a plurality of nozzles for ejecting liquid, a plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with liquid, and a piezoelectric actuator for changing a volume in the pressure chamber; A controller that expands and contracts the volume in the pressure chamber by applying a pulse signal to the piezoelectric actuator, and ejects the liquid filled in the pressure chamber, and the controller includes the pressure One or more expansion pulse signals for expanding the volume in the chamber, or a final applied pulse signal of a drive waveform that overlaps the volume of the pressure chamber. The contraction pulse signal for contracting the volume in the pressure chamber is at least a quarter of the on-pulse peak and less than twice. The liquid ejecting head is characterized in that application is performed with a pulse width of.

  One embodiment of the present invention is characterized in that, in the liquid ejecting head, a pulse width of the final applied pulse signal is not less than ¼ times and not more than ¼ times an on-pulse peak.

  One embodiment of the present invention is characterized in that, in the liquid ejecting head, a pulse width of the final applied pulse signal is not less than one half and not more than one time of an on-pulse peak.

  One embodiment of the present invention is characterized in that, in the liquid jet head, the control unit applies the final applied pulse signal immediately after the last applied expansion pulse signal.

  One embodiment of the present invention is characterized in that, in the liquid jet head, the control unit applies the final application pulse signal after applying a plurality of expansion pulse signals.

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

  According to another aspect of the present invention, there is provided a piezoelectric actuator that includes a plurality of nozzles that eject liquid and a plurality of pressure chambers that correspond to the plurality of nozzles and that are filled with liquid, and that changes a volume in the pressure chamber. And a controller that expands and contracts the volume in the pressure chamber by applying a pulse signal to the piezoelectric actuator, and ejects the liquid filled in the pressure chamber. In the head driving method, the control unit applies one or a plurality of expansion pulse signals for expanding the volume in the pressure chamber, and the control unit uses the pressure waveform as a final application pulse signal of the driving waveform. Applying a contraction pulse signal for contracting the volume of the room with a pulse width of at least one-quarter and less than twice the on-pulse peak. A liquid jet head driving method comprising.

  According to the present invention, it is possible to improve the print image quality by suppressing the length of the ligament without reducing the discharge speed.

1 is a perspective view showing a configuration of a liquid jet recording apparatus in an embodiment of the present invention. FIG. 3 is a perspective view of a liquid ejecting head according to an embodiment of the invention. It is a perspective view of a head chip in an embodiment of the present invention. It is a disassembled perspective view of the head chip in the embodiment of the present invention. It is a schematic block diagram which shows an example of the control part in embodiment of this invention. It is a figure which shows an example of the drive waveform which the control circuit in embodiment of this invention outputs. It is a table | surface which shows the correspondence of the pulse width of the last applied pulse signal, ligament length, and the grade of image quality in embodiment of this invention. It is a figure which shows an example of the printing image of each grade of each image quality in embodiment of this invention. It is a figure which shows the other example of the drive waveform which a control circuit outputs.

(Liquid jet recording device)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of the liquid jet recording apparatus 1 according to the present embodiment will be described.
FIG. 1 is a perspective view showing the configuration of the liquid jet recording apparatus 1. In the following drawings, the scale of each member is appropriately changed for easy explanation.
As shown in the figure, the liquid jet recording apparatus 1 includes a pair of transport means 2 and 3 for transporting a recording medium S such as recording paper, and a liquid ejecting head 4 for ejecting ink (not shown) to the recording medium S. Ink supply means 5 for supplying ink to the liquid ejecting head 4 and scanning means 6 for causing the liquid ejecting head 4 to scan in a scanning direction X orthogonal to the transport direction Y of the recording medium S are provided.
In the present embodiment, the direction perpendicular to the two directions of the conveyance direction Y and the scanning direction X is defined as the vertical direction Z.

The pair of conveying means 2 and 3 are arranged with a gap in the conveying direction Y, one conveying means 2 is located upstream in the conveying direction Y, and the other conveying means 3 is downstream in the conveying direction Y. Is located. The conveying means 2 and 3 are arranged in parallel to the grit rollers 2a and 3a extending in the scanning direction X and the grit rollers 2a and 3a, and are recorded between the grit rollers 2a and 3a. Pinch rollers 2b and 3b that sandwich the medium S and drive mechanisms (not shown) such as motors that rotate the grit rollers 2a and 3a around their axes are provided.
The recording medium S can be transported in the direction of arrow B along the transport direction Y by rotating the grit rollers 2a and 3a of the pair of transport means 2 and 3.

The ink supply unit 5 includes an ink tank 10 that contains ink, and an ink pipe 11 that connects the ink tank 10 and the liquid ejecting head 4.
In the illustrated example, the ink tank 10 is transported by ink tanks 10Y, 10M, 10C, and 10K each containing four color inks of yellow (Y), magenta (M), cyan (C), and black (K). They are arranged side by side in the direction Y. The ink pipe 11 is a flexible hose having flexibility, for example, and can follow the operation (movement) of the carriage 16 that supports the liquid ejecting head 4.

The scanning means 6 includes a pair of guide rails 15 extending in the scanning direction X and arranged in parallel to each other at an interval in the transport direction Y, and a carriage 16 disposed so as to be movable along the pair of guide rails 15. And a drive mechanism 17 for moving the carriage 16 in the scanning direction X.
The drive mechanism 17 is disposed between the pair of guide rails 15, and is moved between the pair of pulleys 18 disposed at a distance in the scanning direction X and the pair of pulleys 18. An endless belt 19 that rotates, and a drive motor 20 that rotationally drives one pulley 18.

The carriage 16 is connected to an endless belt 19 and is movable in the scanning direction X along with the movement of the endless belt 19 by the rotational drive of one pulley 18. In addition, a plurality of liquid jet heads 4 are mounted on the carriage 16 in a state of being aligned in the scanning direction X.
In the illustrated example, there are four liquid ejecting heads 4 that eject yellow (Y), magenta (M), cyan (C), and black (K) inks, that is, liquid ejecting heads 4Y, 4M, 4C, and 4K. It is installed.

(Liquid jet head)
Next, the liquid jet head 4 will be described in detail.
FIG. 2 is a perspective view of the liquid ejecting head 4.
As shown in the figure, the liquid ejecting head 4 uses a fixed plate 25 fixed to the carriage 16, a head chip 26 fixed on the fixed plate 25, and ink supplied from the ink supply means 5. An ink supply unit 27 that further supplies an ink introduction hole 41a (to be described later) of the chip 26 and a control unit 28 that applies a driving voltage to the head chip 26 are provided.

  The liquid ejecting head 4 ejects ink of each color with a predetermined ejection amount when a driving voltage is applied. At this time, the liquid ejecting head 4 is moved in the scanning direction X by the scanning unit 6, so that recording can be performed in a predetermined range on the recording medium S. By repeating this scanning while the recording medium S is transported in the transport direction Y by the transporting means 2 and 3, it is possible to perform recording on the entire recording medium S.

  A base plate 30 made of metal such as aluminum is fixed to the fixing plate 25 in an upright direction Z, and a flow path member 31 that supplies ink to an ink introduction hole 41a described later of the head chip 26. Is fixed. Above the flow path member 31, a pressure buffer 32 having a storage chamber for storing ink is disposed in a state supported by the base plate 30. The flow path member 31 and the pressure buffer 32 are connected via an ink connecting pipe 33, and the ink pipe 11 is connected to the pressure buffer 32.

Under such a configuration, when ink is supplied via the ink pipe 11, the pressure buffer 32 once stores the ink in the internal storage chamber, and then supplies a predetermined amount of ink to the ink connecting pipe 33 and The ink is supplied to the ink introduction hole 41a through the flow path member 31.
The flow path member 31, the pressure buffer 32, and the ink connecting pipe 33 function as the ink supply unit 27.

An IC substrate 36 on which a control circuit 35 such as an integrated circuit for driving the head chip 26 is mounted is attached to the fixed plate 25. The control circuit 35 and a later-described common electrode (drive electrode) and individual electrode (both not shown) of the head chip 26 are electrically connected via a flexible substrate 37 on which a wiring pattern (not shown) is printed. Thereby, the control circuit 35 can apply a driving voltage between the common electrode and the individual electrode via the flexible substrate 37.
The IC substrate 36 and the flexible substrate 37 on which the control circuit 35 is mounted function as the control unit 28.

(Head chip)
Next, the head chip 26 will be described in detail.
FIG. 3 is a perspective view of the head chip 26, and FIG. 4 is an exploded perspective view of the head chip 26.
As shown in FIGS. 3 and 4, the head chip 26 includes an actuator plate 40, a cover plate 41, a support plate 42, and a nozzle plate 60 provided on the side surface of the actuator plate 40.
The head chip 26 is of a so-called edge chute type that ejects ink from a nozzle hole 43a facing a longitudinal end of a liquid ejection channel 45A described later.

  The actuator plate 40 is a so-called laminated plate in which two plates of a first actuator plate 40A and a second actuator plate 40B are laminated. Note that the actuator plate 40 is not limited to a laminated plate, and may be composed of a single plate.

The first actuator plate 40A and the second actuator plate 40B are both piezoelectric substrates that are polarized in the thickness direction, for example, PZT (lead zirconate titanate) ceramic substrates, with the polarization directions of the substrates opposite to each other. It is joined.
The actuator plate 40 is long in a first direction (arrangement direction) L2 orthogonal to the thickness direction L1 and short in a second direction L3 orthogonal to the thickness direction L1 and the first direction L2, and is substantially rectangular in plan view. Is formed.

  Since the head chip 26 of this embodiment is an edge shoot type, the thickness direction L1 coincides with the scanning direction X in the liquid jet recording apparatus 1, the first direction L2 is the transport direction Y, and the second direction L3 is It coincides with the vertical direction Z. That is, for example, of the side surfaces of the actuator plate 40, the side surface facing the nozzle plate 60 (the side on the ink ejection side) is the lower end surface 40a, and is located on the opposite side of the second direction L3 from the lower end surface 40a. The side surface to be used is the upper end surface 40b. In the following description, it may be described simply as “lower side” and “upper side” in the vertical direction. However, it goes without saying that the vertical direction usually changes depending on the installation angle of the liquid jet recording apparatus 1.

  A plurality of channels 45 arranged at predetermined intervals in the first direction L2 are formed on one main surface (surface on which the cover plate 41 overlaps) 40c of the actuator plate 40. The plurality of channels 45 are grooves extending linearly along the second direction L3 in a state opened to the one main surface 40c side, and one side in the longitudinal direction opens to the lower end surface 40a side of the actuator plate 40. Yes. A drive wall (piezoelectric partition wall) 46 having a substantially rectangular cross section and extending in the second direction L3 is formed between the plurality of channels 45. Each channel 45 is divided by the drive wall 46.

The plurality of channels 45 are roughly divided into a liquid ejection channel 45A filled with ink and a non-ejection channel 45B not filled with ink. The liquid discharge channels 45A and the non-discharge channels 45B are alternately arranged in the first direction L2.
Among these, the liquid discharge channel 45 </ b> A is formed so as not to open to the upper end surface 40 b side of the actuator plate 40 but to open only to the lower end surface 40 a side. On the other hand, the non-ejection channel 45B is formed not only on the lower end surface 40a side of the actuator plate 40 but also on the upper end surface 40b side.

A common electrode (not shown) is formed on the inner wall surface of the liquid discharge channel 45A, that is, the pair of side wall surfaces and the bottom wall surface facing the first direction L2. The common electrode extends in the second direction L3 along the liquid discharge channel 45A and is electrically connected to the common terminal 51 formed on one main surface 40c of the actuator plate 40.
On the other hand, individual electrodes (not shown) are formed on the pair of side wall surfaces facing the first direction L2 among the inner wall surfaces of the non-ejection channel 45B. These individual electrodes extend in the second direction L3 along the non-ejection channel 45B and are electrically connected to the individual terminals 53 formed on one main surface 40c of the actuator plate 40.

  The individual terminal 53 is formed on the upper end surface 40 b side of the common terminal 51 on the one main surface 40 c of the actuator plate 40. The individual electrodes located on both sides of the liquid discharge channel 45A (individual electrodes formed in different non-discharge channels 45B) are connected to each other.

  Under such a configuration, when the control circuit 35 applies a drive voltage between the common electrode and the individual electrode through the flexible substrate 37 and the common terminal 51 and the individual terminal 53, the drive wall 46 is deformed. . Then, pressure fluctuation occurs in the ink filled in the liquid discharge channel 45A. Accordingly, the ink in the liquid discharge channel 45A can be discharged from the nozzle hole 43a, and various information such as characters and figures can be recorded on the recording medium S.

A cover plate 41 is overlaid on one main surface 40 c of the actuator plate 40. In the cover plate 41, an ink introduction hole 41a is formed in a substantially rectangular shape in plan view long in the first direction L2.
The ink introduction hole 41a is formed with a plurality of slits 55a for introducing the ink supplied through the flow path member 31 into the liquid ejection channel 45A and restricting the introduction into the non-ejection channel 45B. An ink introduction plate 55 is formed. That is, the plurality of slits 55a are formed at positions corresponding to the liquid discharge channels 45A, and ink can be filled only into each liquid discharge channel 45A.

  The cover plate 41 is formed of, for example, the same PZT ceramic substrate as the actuator plate 40, and suppresses warping and deformation with respect to a temperature change by causing the same thermal expansion as the actuator plate 40. However, the present invention is not limited to this case, and the cover plate 41 may be formed of a material different from that of the actuator plate 40. In this case, it is preferable to use a material having a thermal expansion coefficient close to that of the actuator plate 40 as the material of the cover plate 41.

  The support plate 42 supports the actuator plate 40 and the cover plate 41 that are superimposed, and simultaneously supports the nozzle plate 60. The support plate 42 is a substantially rectangular plate material that is formed long in the first direction L2 so as to correspond to the actuator plate 40, and a fitting hole 42a penetrating in the thickness direction is formed in a large part of the center. Yes. The fitting hole 42a is formed in a substantially rectangular shape along the first direction L2, and supports the overlapped actuator plate 40 and cover plate 41 in a state of fitting into the fitting hole 42a. .

  Further, the support plate 42 is formed in a stepped plate shape such that the outer shape thereof becomes smaller by a step as it goes to the lower end in the thickness direction. That is, the support plate 42 has a base portion 42A located on the upper end side in the thickness direction, and a step portion 42B that is disposed on the lower end surface of the base portion 42A and has an outer shape smaller than the base portion 42A. Are integrally formed. The support plate 42 is combined so that the end surface of the stepped portion 42B is flush with the lower end surface 40a of the actuator plate 40. Further, the nozzle plate 60 is fixed to the end face of the stepped portion 42B, for example, by adhesion.

(Control part)
Next, the control unit 28 will be described in detail. FIG. 5 is a schematic block diagram illustrating an example of the control unit 28. As shown in this figure, in the control unit 28, the control circuit 35 mounted on the IC substrate 36 is connected to the common electrode and the individual electrode through the flexible substrate 37 and further through the common terminal 51 and the individual terminal 53 of the actuator plate 40, respectively. Electrically connected.

  The control circuit 35 applies a drive voltage (pulse signal) between the common electrode and the individual electrode of the actuator plate 40. As a result, the drive wall 46 is deformed, the volume in the liquid discharge channel 45A (pressure chamber) expands and contracts, and ink (liquid) filled in the liquid discharge channel 45A is ejected from the nozzle holes 43a.

  Here, the control circuit 35 expands the volume in the liquid discharge channel 45A by applying a positive pulse signal (expansion pulse signal) having a positive drive voltage between the common electrode and the individual electrode. The control circuit 35 contracts the volume in the liquid ejection channel 45A by applying a negative pulse signal (contraction pulse signal) having a negative drive voltage between the common electrode and the individual electrode.

  In addition, the control circuit 35 includes a plurality of drive waveforms that vary the volume (droplet size) of the droplet by overlapping one or more positive pulse signals. In other words, the control circuit 35 can discharge droplet sizes with multiple gradations. Thereby, it is possible to cover a small droplet to a large droplet and to improve the image quality. That is, when forming a recording of 1 dot (pixel), the amount of liquid used for the recording of 1 dot can be changed by ejecting and combining a plurality of droplets. For example, large dots formed by combining three to four drops of liquid with one dot, medium dots formed by combining two drops of liquid, and standard dots formed with one drop of liquid are formed. The droplet size changes according to the number of times the positive pulse signal is applied. Specifically, the larger the number of positive pulse signals to be applied, the larger the droplet size.

  In addition, the control circuit 35 applies a negative pulse signal as the last applied pulse signal applied at the end of the drive waveform. As a result, a ligament made of ink ejected from the nozzle hole 43a by applying a positive pulse signal (that is, expanding the volume in the liquid ejection channel 45A) is discharged by applying a negative pulse signal. It can be cut off halfway by shrinking the volume in channel 45A. Thereby, the length of the ink ligament can be suppressed.

FIG. 6 is a diagram illustrating an example of a drive waveform output from the control circuit 35.
In this figure, the horizontal axis is time. In addition, this figure shows a drive waveform when a positive pulse signal is applied once.

  The control circuit 35 immediately applies one positive pulse signal P1 having a positive drive voltage at an on-pulse peak (Acoustic Period) or an arbitrary pulse width set in advance, and the drive voltage is negative as the final applied pulse signal. The negative pulse signal P2 is applied with a pulse width that is at least a quarter of the on-pulse peak and less than twice. The on-pulse peak (hereinafter referred to as AP) is a liquid discharge channel 45A (pressure chamber) that stores ink, a nozzle hole 43a that communicates with the liquid discharge channel 45A and ejects ink from the liquid discharge channel 45A, and a liquid discharge For the liquid ejecting head 4 having the actuator plate 40 that expands or contracts the volume of the channel 45A, 1/2 of the natural vibration period of the ink in the liquid ejection channel 45A (pressure chamber) is set to 1AP. In the present embodiment, the pulse width of the last applied pulse signal P2 is a period from the end (falling) of the immediately preceding positive pulse signal P1 to the end (rising) of the last applied pulse signal P2.

  That is, the last applied pulse signal that is applied last in the drive waveform is a negative pulse signal having a pulse width that is equal to or greater than one-quarter and less than twice the AP. By applying such a final applied pulse signal, the ligament made of the ink ejected from the nozzle hole 43a can be cut halfway, and the length of the ligament can be suppressed by 30% at the maximum.

  FIG. 7 is a table showing a correspondence relationship between the pulse width of the final applied pulse signal, the ligament length, and the degree of image quality. This figure shows experimental results when the image shown in FIG. 8 is printed. In this figure, the pulse width of the final applied pulse signal indicates how many times the pulse width of the final applied pulse signal is AP. The ligament length is the length of the ligament, and its unit is μm (micrometer). The degree of image quality indicates the degree of image quality in stages from A to D.

  FIG. 8 is a diagram illustrating an example of a print image for each degree of image quality. FIG. 8A shows an example of a print image corresponding to the degree “A”. As shown in the figure, at the degree “A”, the edge is printed sharply and the image quality is good. FIG. 8B shows an example of a print image corresponding to the degree “B”. As shown in the figure, at the degree “B”, the edge looks slightly broad, and the image quality is worse than the degree “A”. FIG. 8C shows an example of a print image corresponding to the degree “C”. As shown in the drawing, at the degree “C”, the edge looks broad, and the image quality is worse than that at the degree “B”. FIG. 8D shows an example of a print image corresponding to the degree “D”. As shown in the figure, at the degree “D”, the boundary between the edges is unclear, and the image quality is worse than that at the degree “C”.

  As shown in FIG. 7, when the pulse width of the final applied pulse signal is not less than 1/4 times AP but less than 2 times, the image quality is “C” or more, and satellites and mists are applied from “D”. Can be suppressed. Further, when the pulse width of the final applied pulse signal is not less than 1/4 times and not more than 5 times the AP, the degree of image quality is “B” or more, and satellites and mists are suppressed more than “C”. be able to. In addition, when the pulse width of the final applied pulse signal is not less than one-half and not more than one-fold of AP, the image quality is “A”, and satellites and mist can be most suppressed.

  Further, when the pulse width of the final applied pulse signal is less than 1/4 of AP, the frequency characteristic tends to be unstable, whereas the pulse width of the final applied pulse signal is 1/4 of AP. If the frequency is greater than or equal to twice and less than or equal to five times, the frequency characteristics tend to be stable. The frequency characteristic is an index indicating the relationship between the number of droplets discharged per second (driving frequency) discharged from the nozzle hole 43a and the discharge speed. Therefore, the fact that the frequency characteristic is stable means that the ejection speed does not change in any frequency band. On the other hand, the fact that the frequency characteristics are not stable means that the ejection speed changes depending on the drive frequency. For this reason, when the frequency characteristics are not stable, if the drive frequency changes (that is, the discharge amount varies depending on the printing location), the discharge speed changes, so that the landing position of the droplet is shifted, resulting in a decrease in image quality. To do. Furthermore, if the discharge speed is too low, there is a possibility that the droplets cannot be discharged.

  As described above, the liquid jet recording apparatus 1 according to this embodiment includes a plurality of nozzle holes 43a that eject liquid, and a plurality of liquid ejection channels 45A that correspond to each of the plurality of nozzle holes 43a and are filled with liquid. And applying a pulse signal to the actuator plate 40 to expand and contract the volume in the liquid discharge channel 45A, so that the volume in the liquid discharge channel 45A is increased. And a control circuit 35 for ejecting the liquid filled in the control circuit 35. The control circuit 35 has one or more expansion pulse signals for expanding the volume in the liquid discharge channel 45A as a final application pulse signal of a drive waveform to be superimposed. A contraction pulse signal for contracting the volume in the liquid discharge channel 45A is a quarter of the on-pulse peak. Including a liquid ejecting head 4, characterized in that applied at less than two times the pulse width or more.

  Accordingly, the ligament length can be suppressed and satellites and mists can be reduced without decreasing the discharge speed, and the print image quality can be improved.

  Further, the pulse width of the final applied pulse signal may be not less than ¼ times and not more than ¼ times the on-pulse peak. Thereby, the frequency characteristic can be stabilized.

  Further, the pulse width of the final applied pulse signal may be not less than one half and not more than one time the on-pulse peak. Thereby, the ligament length can be further suppressed, satellites and mist can be reduced, and the print image quality can be further improved.

  The control circuit 35 applies the final applied pulse signal immediately after the last applied expansion pulse signal. Thereby, the ligament length can be further suppressed, satellites and mist can be reduced, and the print image quality can be further improved.

  Further, the control circuit 35 applies the final applied pulse signal after applying a plurality of expansion pulse signals. As a result, even when the droplet size is large, the ligament length can be suppressed, satellites and mist can be reduced, and the print image quality can be improved.

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

  For example, in the above-described embodiment, the case where the head chip 26 is of a so-called edge chute type that discharges ink from the nozzle hole 43a facing the longitudinal end of the liquid discharge channel 45A has been described. However, the present invention is not limited to this, and the configuration of the above-described embodiment can also be applied to a so-called side shoot type head chip that ejects ink from a nozzle hole facing the longitudinal center of the liquid ejection channel 45A. It is. Further, the liquid ejecting head 4 may be a circulation type liquid ejecting head for returning the ink supplied to each liquid ejection channel 45A to the storage chamber of the pressure buffer 32, or a non-circulating type liquid ejecting head. There may be.

  In the above-described embodiment, the pair of transport units 2 and 3 that transport the recording medium S such as recording paper and the liquid ejecting head 4 are scanned in the scanning direction X orthogonal to the transport direction Y of the recording medium S. The liquid jet recording apparatus 1 that records by moving the scanning means 6 has been described. Instead, the liquid jet recording apparatus that fixes the scanning means 6 and the moving mechanism moves the recording medium in a two-dimensional manner for recording. It may be a recording device. That is, the moving mechanism may be any mechanism that relatively moves the liquid ejecting head and the recording medium.

  In the above-described embodiment, the case where the positive pulse signal is the expansion pulse signal has been described. However, the expansion pulse signal is a negative pulse signal as long as it substantially expands the volume in the liquid discharge channel 45A. Also good. Similarly, the contraction pulse signal may be a positive pulse signal as long as it substantially contracts the volume in the liquid discharge channel 45A.

  In the embodiment described above, the control circuit 35 applies the negative pulse signal immediately after the last positive pulse signal. However, the present invention is not limited to this, and a predetermined time from the end (falling) of the last positive pulse signal. You may apply a negative pulse signal after progress. FIG. 9 is a diagram illustrating another example of the drive waveform output by the control circuit 35. In FIG. In the example shown in the figure, the control circuit 35 applies the negative pulse signal P12 after a lapse of a predetermined time from the end (falling) of the last positive pulse signal P11. That is, the drive waveform shown in the figure is a staircase waveform from the last positive pulse signal P11 to the last applied pulse signal P12. The predetermined time, that is, the period from the end (falling) of the positive pulse signal P11 to the start (falling) of the final applied pulse signal P12 is preferably 0.4 microseconds or less. For example, when the predetermined time is 0.2 microseconds to 0.4 microseconds, power consumption can be reduced. Even when a negative pulse signal is applied after a lapse of a predetermined time from the last positive pulse signal, the pulse width of the last applied pulse signal is changed from the end (falling) of the last positive pulse signal to the end of the last applied pulse signal ( The length is from 1/4 to less than 2 times the AP.

  Note that all or some of the functions of each unit included in the control circuit 35 in the embodiment described above are recorded on a computer-readable recording medium and a program for realizing these functions is recorded on the recording medium. You may implement | achieve by making a computer system read a program and executing it. Here, the “computer system” includes an OS and hardware such as peripheral devices.

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

  Further, the control circuit 35 in the above-described embodiment may be realized as an integrated circuit such as an LSI (Large Scale Integration). Further, for example, the control circuit 35 may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology, an integrated circuit based on the technology may be used.

DESCRIPTION OF SYMBOLS 1 ... Liquid jet recording apparatus, 4 ... Liquid jet head, 28 ... Control part, 35 ... Control circuit, 36 ... IC board, 37 ... Flexible board, 40 ... Actuator plate, 43a ... Nozzle hole, 45 ... Channel, 45A ... Liquid Discharge channel 51 ... Common terminal 53 ... Individual terminal

Claims (7)

A plurality of nozzles for ejecting liquid;
A plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with a liquid, and a piezoelectric actuator for changing a volume in the pressure chamber;
A controller that expands and contracts the volume in the pressure chamber by applying a pulse signal to the piezoelectric actuator, and ejects the liquid filled in the pressure chamber;
With
The control unit uses one or more expansion pulse signals for expanding the volume in the pressure chamber as a final applied pulse signal of a drive waveform to be superimposed, and a contraction pulse signal for contracting the volume in the pressure chamber is divided into four on-pulse peaks. The liquid jet head is characterized by being applied with a pulse width that is 1 to 2 times as long as. 2. The liquid jet head according to claim 1, wherein a pulse width of the final applied pulse signal is not less than ¼ times and not more than ¼ times an on-pulse peak. 3. The liquid ejecting head according to claim 1, wherein a pulse width of the final applied pulse signal is not less than a half of an on-pulse peak and not more than 1 time. The liquid ejecting head according to claim 1, wherein the control unit applies the final applied pulse signal immediately after the last applied expansion pulse signal. The liquid ejecting head according to claim 1, wherein the control unit applies the final applied pulse signal after applying a plurality of expansion pulse signals. The liquid jet head according to any one of claims 1 to 5,
A liquid jet recording apparatus comprising: A plurality of nozzles for ejecting liquid;
A plurality of pressure chambers corresponding to each of the plurality of nozzles and filled with a liquid, and a piezoelectric actuator for changing a volume in the pressure chamber;
A controller that expands and contracts the volume in the pressure chamber by applying a pulse signal to the piezoelectric actuator, and ejects the liquid filled in the pressure chamber;
A liquid jet head driving method in a liquid jet head comprising:
The control unit applying one or a plurality of expansion pulse signals for expanding the volume in the pressure chamber;
The control unit applying a contraction pulse signal for contracting the volume in the pressure chamber as a final application pulse signal of a drive waveform with a pulse width less than or equal to a quarter of an on-pulse peak and less than twice;
A liquid ejecting head driving method comprising: