JP2014004706A - Liquid ejection device and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection device that can suppress occurrence of a mist while securing ejection stability, and further to provide a control method therefor.SOLUTION: In a case where pixel data SI corresponding to a current unit period T(n) are data indicating use of a second ejection driving pulse P2, first driving waveform, or a fifth ejection driving pulse P5, second driving waveform, when a leading bit of the pixel data SI corresponding to a subsequent unit period T(n+1) is "0", a first state, a front stage portion P2a of the second ejection driving pulse P2 and a rear stage portion P4b of a micro-vibration driving pulse P4 are combined together and are applied to a piezoelectric element as the fifth ejection driving pulse P5. On the other hand, when the leading bit of the pixel data SI corresponding to the subsequent unit period T(n+1) is "1", a second state, the second ejection driving pulse P2 is selected and is applied to the piezoelectric element.

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet recording apparatus, and a control method for the liquid ejecting apparatus, and in particular, drives the pressure generating means by applying a driving waveform included in a driving signal to the pressure generating means, The present invention relates to a liquid ejecting apparatus that ejects a liquid from a nozzle by causing a pressure fluctuation in a liquid in a pressure chamber communicating with the nozzle, and a control method for the liquid ejecting apparatus.

  The liquid ejecting apparatus includes a liquid ejecting head and ejects (discharges) various liquids from the liquid ejecting head. As this liquid ejecting apparatus, for example, there are image recording apparatuses such as an ink jet printer and an ink jet plotter. Recently, various types of liquid ejecting apparatuses are utilized by utilizing the feature that a very small amount of liquid can be accurately landed on a predetermined position. It is also applied to devices. For example, a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display, an electrode forming apparatus for forming an electrode such as an organic EL (Electro Luminescence) display or FED (surface emitting display), a chip for manufacturing a biochip (biochemical element) Applied to manufacturing equipment. The recording head for the image recording apparatus ejects liquid ink, and the color material ejecting head for the display manufacturing apparatus ejects solutions of R (Red), G (Green), and B (Blue) color materials. The electrode material ejecting head for the electrode forming apparatus ejects a liquid electrode material, and the bioorganic matter ejecting head for the chip manufacturing apparatus ejects a bioorganic solution.

  In the above liquid ejecting head, the droplet ejected from the nozzle is stretched during the flight, and is separated into a leading main droplet (main droplet) and a satellite droplet (sub-droplet) after that. . Further, a mist smaller than the satellite droplet is also generated. This mist drifts in the apparatus without reaching the recording medium and contaminates the inside of the apparatus, and may cause malfunction due to adhesion to easily charged members such as a recording head and an electric circuit. In particular, when a liquid in a high viscosity region having a viscosity of 8 mPa · s or more at normal temperature (for example, 25 ° C.) is ejected, mist is more likely to occur. Further, mist tends to be generated more easily as the amount of liquid droplets to be ejected is larger.

  In order to prevent such a problem, an invention has been proposed in which the mist generated when a droplet is ejected is suppressed by devising a driving waveform (driving pulse) for driving the pressure generating means (for example, Patent Documents). 1). Specifically, by making the portion where the potential of the drive waveform changes into a plurality of stages, it is possible to prevent the outer peripheral side and the center side of the meniscus in the nozzle from being in opposite phases. Thereby, it is reduced that the droplets ejected from the nozzles extend excessively in the flight direction, and the generation of satellite droplets and mist is suppressed. In addition, by further extruding the meniscus to the ejection side after the droplets are ejected from the nozzle, the mist is absorbed by the extruded meniscus, thereby further reducing the generation of mist. Hereinafter, a drive waveform configured to be capable of suppressing mist is appropriately referred to as a mist suppression waveform.

JP 2011-020280 A

  However, since the above mist suppression waveform has a more complicated potential change than a general drive waveform in which mist countermeasures are not taken, the liquid in the pressure chamber is ejected when droplets are ejected using the mist suppression waveform. There was the problem of exciting more complex vibrations. The behavior of the meniscus is disturbed by the residual vibration after droplet ejection by the mist suppression waveform, which may adversely affect the subsequent droplet ejection operation. In particular, when droplets are continuously ejected at a higher driving frequency, there is a problem that ejection stability deteriorates. That is, the flying bend of the droplet ejected from the nozzle occurs. As a result, the flying droplets may not land at a predetermined position.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid ejecting apparatus capable of suppressing the occurrence of mist while ensuring ejection stability, and a control method therefor. There is.

The liquid ejecting apparatus of the present invention has been proposed in order to achieve the above-described object, and causes a pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and the liquid is discharged from the nozzle using the pressure fluctuation. A liquid ejecting head to be ejected;
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
With
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes at least a second driving waveform that is generated at substantially the same timing as the first driving waveform at the end of the repetition period of the driving signal. And
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The second drive waveform includes the first potential changing unit, a maintaining unit that maintains the second potential, which is a terminal potential of the first potential changing unit, for a certain period of time, and a terminal potential of the maintaining element. A second potential changing section that changes in potential from the second potential to the third potential on the first polarity side;
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the second driving waveform is selected and applied to the pressure generating means, while the first bit of the injection control data corresponding to the next repetition period is in the second state. The first drive waveform is selected and applied to the pressure generating means.

  According to the present invention, since the first drive waveform and the second drive waveform are selectively used based on the first bit of the injection control data corresponding to the current repetition cycle and the injection control data corresponding to the next repetition cycle, the injection stability It is possible to suppress the generation of mist while ensuring the above. That is, when the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the first bit of the injection control data corresponding to the next repetition cycle is the first. When it is in a state, after the droplet is ejected at the end of the current repetition cycle, the time until the first droplet is ejected after the next repetition cycle becomes relatively long. In this case, generation of mist is suppressed by ejecting droplets using the second drive waveform at the current repetition period. In addition, since the time until the next droplet ejection is relatively long, the residual vibration caused by ejecting the droplet using the second drive waveform is attenuated until the next droplet ejection. It is suppressed that stability is impaired. On the other hand, when the first bit of the ejection control data corresponding to the next repetition cycle is in the second state, the droplet is ejected at the beginning of the next repetition cycle shortly after the droplet is ejected at the end of the current repetition cycle. Therefore, even if mist is generated by the last droplet ejection of the current repetition cycle, the mist is absorbed by the droplet ejected at the beginning of the next repetition cycle. Therefore, in this case, by ejecting droplets using the first drive waveform at the current repetition period, the ejection is stabilized without complicating the residual vibration while suppressing the occurrence of mist.

Further, the liquid ejecting apparatus of the present invention generates a pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating unit, and ejects the liquid from the nozzle using the pressure fluctuation; and
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
With
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes a waveform portion that is generated at the end of the repetition period of the driving signal and used in combination with the first driving waveform.
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The waveform section includes a maintaining section that maintains the second potential for a certain period of time, and a first potential that changes from the second potential, which is a terminal potential of the maintaining section, to the third potential. 2 potential change portions,
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the waveform is combined and applied to the pressure generating means after the first potential change portion of the first drive waveform, and the injection corresponding to the next repetition period When the first bit of the control data is in the second state, the first driving waveform is selected and applied to the pressure generating means.

  According to the present invention, the first drive waveform and the first potential change of the first drive waveform based on the injection control data corresponding to the current repetition period and the first bit of the injection control data corresponding to the next repetition period. Since the combination of the portion and the waveform portion is properly used, it is possible to suppress the occurrence of mist while ensuring the injection stability. That is, when the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the first bit of the injection control data corresponding to the next repetition cycle is the first. When it is in a state, after the droplet is ejected at the end of the current repetition cycle, the time until the first droplet is ejected after the next repetition cycle becomes relatively long. In this case, generation of mist is suppressed by ejecting liquid droplets by combining the first potential change portion and the waveform portion of the first drive waveform in the current repetition period. In addition, since the time until the next droplet is ejected is relatively long, the residual vibration caused by ejecting the droplet using the above combination is attenuated until the next droplet ejection. Is prevented from being damaged. On the other hand, when the first bit of the ejection control data corresponding to the next repetition cycle is in the second state, the droplet is ejected at the beginning of the next repetition cycle shortly after the droplet is ejected at the end of the current repetition cycle. Therefore, even if mist is generated by the last droplet ejection of the current repetition cycle, the mist is absorbed by the droplet ejected at the beginning of the next repetition cycle. Therefore, in this case, by ejecting droplets using the first drive waveform at the current repetition period, the ejection is stabilized without complicating the residual vibration while suppressing the occurrence of mist.

  In the above configuration, it is preferable that the head control unit includes a storage unit that stores the injection control data corresponding to the current repetition cycle and the first bit of the injection control data corresponding to the next repetition cycle.

  According to this configuration, it is possible to perform selective application control of the drive waveform based on the injection control data corresponding to the current repetition period and the first bit of the injection control data corresponding to the next repetition period.

Further, the control method of the liquid ejecting apparatus of the present invention includes a liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and ejects the liquid from the nozzle using the pressure fluctuation.
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
A control method for a liquid ejecting apparatus comprising:
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes at least a second driving waveform that is generated at substantially the same timing as the first driving waveform at the end of the repetition period of the driving signal. And
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The second drive waveform includes the first potential changing unit, a maintaining unit that maintains the second potential, which is a terminal potential of the first potential changing unit, for a certain period of time, and a terminal potential of the maintaining element. A second potential changing section that changes in potential from the second potential to the third potential on the first polarity side;
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the second driving waveform is selected and applied to the pressure generating means, while the first bit of the injection control data corresponding to the next repetition period is in the second state. The first drive waveform is selected and applied to the pressure generating means.

Furthermore, the control method of the liquid ejecting apparatus of the present invention includes a liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating unit, and ejects liquid from the nozzle using the pressure fluctuation.
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
A control method for a liquid ejecting apparatus comprising:
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes a waveform portion that is generated at the end of the repetition period of the driving signal and used in combination with the first driving waveform.
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The waveform section includes a maintaining section that maintains the second potential for a certain period of time, and a first potential that changes from the second potential, which is a terminal potential of the maintaining section, to the third potential. 2 potential change portions,
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the waveform is combined and applied to the pressure generating means after the first potential change portion of the first drive waveform, and the injection corresponding to the next repetition period When the first bit of the control data is in the second state, the first driving waveform is selected and applied to the pressure generating means.

2 is a block diagram illustrating an electrical configuration of a printer. FIG. 2 is a perspective view illustrating an internal configuration of the printer. FIG. FIG. 3 is a cross-sectional view illustrating a configuration of a recording head. It is a wave form diagram explaining the structure of a drive signal. It is a wave form diagram explaining the structure of a drive pulse. It is a schematic diagram explaining a mode that an ink droplet is ejected from a nozzle. It is a wave form diagram explaining the selection pattern of a drive pulse. It is a wave form diagram explaining the structure of the drive signal in 2nd Embodiment.

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

  FIG. 1 is a block diagram illustrating the electrical configuration of the printer 1, and FIG. 2 is a perspective view illustrating the internal configuration of the printer 1. The external device 2 is an electronic device that handles images, such as a computer or a digital camera. The external device 2 is communicably connected to the printer 1 and transmits print data corresponding to the image or the like to the printer 1 so that the printer 1 prints an image or text on a recording medium such as recording paper.

  The printer 1 in this embodiment includes a paper feed mechanism 3, a carriage moving mechanism 4, a linear encoder 5, a recording head 6, and a printer controller 7. The recording head 6 is fixed to the bottom surface side of the carriage 16 on which the ink cartridge 17 is mounted. The carriage 16 is configured to reciprocate along the guide rod 18 by the carriage moving mechanism 4. In other words, the printer 1 sequentially transports the recording medium (recording paper) by the paper feeding mechanism 3 and moves the recording head 6 relative to the recording medium while the ink is ejected from the nozzle 34 (see FIG. 3) of the recording head 6. Are ejected to land the ink on the recording medium, thereby recording an image or the like.

  The printer controller 7 is a control unit that controls each part of the printer. The printer controller 7 includes an interface (I / F) unit 8, a CPU 9, a storage unit 10, and a drive signal generation unit 11. The interface unit 37 transmits / receives printer status data when sending print data or a print command from the external device 2 to the printer 1 or outputting status information of the printer 1 to the external device 2 side. The CPU 9 is an arithmetic processing device for controlling the entire printer. The memory | storage part 10 is an element which memorize | stores the data used for the program and various control of CPU9, and contains ROM, RAM, and NVRAM (nonvolatile memory element). The CPU 9 controls each unit according to a program stored in the storage unit 10.

  Further, the CPU 9 outputs a head control signal used for controlling the recording head 6 to the head control unit 14 side of the recording head 6. The head control signal is, for example, a transfer clock CLK, pixel data SI, a latch signal LAT, and a change signal CH. These latch signal LAT and change signal CH are selection control signals used for selective application control of drive pulses included in drive signals COM1 and 2, which will be described later, to the piezoelectric element 22. The CPU 9 generates the latch signal LAT and the change signal CH based on the timing pulse PTS output from the linear encoder 5 in accordance with the movement of the recording head 6 in the main scanning direction. The latch signal LAT is a signal that defines the start timing of the pixel recording cycle, and, as described above, is a signal that defines the repetitive generation cycle (hereinafter, unit cycle T) of the drive signal COM. The latch signal LAT is also a signal that defines the application timing of the drive pulse generated first in the drive signal COM to the piezoelectric element. The change signal CH is a signal that generates a change pulse at a predetermined interval after the latch signal LAT, and is a signal that defines the application timing of each drive pulse included in the drive signal COM to the piezoelectric element 22. is there.

  The pixel data SI is data relating to pixels printed on the recording medium, and is a kind of ejection control data. Here, a pixel is a dot formation region virtually defined on a recording medium such as a recording paper that is a landing target, and is a structural unit such as an image. The pixel data SI in the print data includes data relating to the presence / absence of dots formed on the recording medium (or presence / absence of ink ejection) and the size of the dots (or the amount of ink ejected), that is, gradation values. . In the present embodiment, the pixel data SI is composed of 2-bit gradation values. In the present embodiment, as the pixel data SI, data [00] corresponding to non-recording (fine vibration) without dots, data [10] corresponding to small dots, and data [01] corresponding to formation of medium dots. ] And data [11] corresponding to a large dot. Therefore, this printer in this embodiment can form dots with four gradations. The width of this pixel corresponds to the distance that the recording head 6 moves in the unit period T.

  The drive signal generator 11 generates an analog voltage signal based on waveform data relating to the waveform of the drive signal. The drive signal generator 11 amplifies the voltage signal to generate the drive signal COM. As shown in FIG. 4, the drive signal generation unit 11 in the present embodiment is configured to generate a plurality of drive signals COM, and specifically, two types of drive signals (first drive signal COM1). , The second drive signal COM2) is generated. Details of each drive signal will be described later.

  Next, the print engine 13 will be described. As shown in FIG. 1, the print engine 13 includes a paper feed mechanism 3, a carriage moving mechanism 4, a linear encoder 5, a recording head 6, and the like. The carriage moving mechanism 4 includes a carriage 16 to which a recording head 6 that is a kind of liquid ejecting head is attached, a drive motor (for example, a DC motor) that drives the carriage 16 via a timing belt or the like (see FIG. The recording head 6 mounted on the carriage 16 is moved in the main scanning direction. The paper feed mechanism 3 includes a paper feed motor, a paper feed roller, and the like, and sequentially feeds recording paper (one type of recording medium and one type of liquid landing target) onto the platen to perform sub-scanning. Further, the linear encoder 5 outputs an encoder pulse corresponding to the scanning position of the recording head 6 mounted on the carriage 16 to the printer controller 7 as position information in the main scanning direction. The printer controller 7 can grasp the scanning position (current position) of the recording head 6 based on the encoder pulse received from the linear encoder 5 side.

  FIG. 3 is a cross-sectional view of a main part for explaining the configuration of the recording head 6. The recording head 6 includes a case 19, a vibrator unit 15 (broad pressure generating means) housed in the case 19, a flow path unit 20 joined to the bottom surface (tip surface) of the case 19, and the like. ing. The case 19 is made of, for example, an epoxy resin, and a housing empty portion 21 in which the vibrator unit 15 is housed is formed. The vibrator unit 15 includes a piezoelectric element 22 that functions as pressure generation means in a narrow sense, a fixing plate 23 to which the piezoelectric element 22 is bonded, and a flexible cable 24 that supplies a driving signal (driving pulse) to the piezoelectric element 22. I have. The piezoelectric element 22 is a laminated type produced by cutting a piezoelectric plate in which piezoelectric layers and electrode layers are alternately laminated into a comb-like shape, and can be expanded and contracted in a direction perpendicular to the laminating direction (electric field direction) ( It is a piezoelectric element of a longitudinal vibration mode that is a field transverse effect type).

  The flow path unit 20 is configured by joining a nozzle plate 27 to one surface of the flow path forming substrate 26 and a diaphragm 28 to the other surface of the flow path forming substrate 26. The flow path unit 20 is provided with a reservoir 30 (common liquid chamber), an ink supply port 31, a pressure chamber 32, a nozzle communication port 33, and a nozzle 34. A series of ink flow paths from the ink supply port 31 to the nozzle 34 through the pressure chamber 32 and the nozzle communication port 33 are formed corresponding to each nozzle 34. The nozzle plate 27 is a thin plate made of metal such as stainless steel in which a plurality of nozzles 34 are formed in a row at a pitch (for example, 360 dpi) corresponding to the dot formation density. The nozzle plate 27 is provided with a plurality of nozzle rows 35 (nozzle groups) by arranging nozzles 34, and one nozzle row 35 is composed of, for example, 360 nozzles 34.

  The diaphragm 28 has a double structure in which an elastic film 38 is laminated on the surface of a support plate 37. In the present embodiment, the vibration plate 28 is manufactured using a composite plate material in which a stainless plate, which is a kind of metal plate, is used as the support plate 37 and a resin film is laminated on the surface of the support plate 37 as an elastic film 38. The diaphragm 28 is provided with a diaphragm portion 39 that changes the volume of the pressure chamber 32. The diaphragm 28 is provided with a compliance portion 40 that seals a part of the reservoir 30.

  The diaphragm 39 is produced by partially removing the support plate 37 by etching or the like. That is, the diaphragm portion 39 includes an island portion 41 to which the distal end surface of the piezoelectric element 22 is joined, and an elastic portion 42 surrounding the island portion 41. The compliance part 40 is produced by removing the support plate 37 in the region facing the opening surface of the reservoir 30 by etching or the like in the same way as the diaphragm part 39, and the pressure fluctuation of the liquid stored in the reservoir 30 is reduced. Functions as a damper to absorb.

  Since the tip end surface of the piezoelectric element 22 is joined to the island portion 41, the volume of the pressure chamber 32 can be changed by expanding and contracting the free end portion of the piezoelectric element 22. A pressure fluctuation occurs in the ink in the pressure chamber 32 in accordance with the volume fluctuation. The recording head 6 ejects ink from the nozzles 34 using this pressure fluctuation.

Next, the electrical configuration of the recording head 6 will be described.
As shown in FIG. 1, the recording head 6 includes a data storage unit 45 (a kind of storage means in the present invention), a decoder 46, a switch 47, and the piezoelectric element 22. The data storage unit 45, the decoder 46, and the switch 47 are provided for each piezoelectric element 22, that is, for each nozzle 34. The data storage unit 45 is composed of a memory of 3 bits, and the pixel data SI (2 bits) corresponding to the current unit cycle T (n) and the head of the pixel data SI corresponding to the next unit cycle T (n + 1). A bit (1 bit) is stored. By configuring the data storage unit 45 in this manner, as described later, the pixel data SI corresponding to the current unit cycle T (n) and the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) are used. Based on this, it is possible to perform selective application control of the drive pulse.

  The decoder 46 switches the switch 47 based on the pixel data SI corresponding to the current unit period T (n) and the first bit of the pixel data SI corresponding to the next unit period T (n + 1) stored in the data storage unit 45. A switch control signal sw to be controlled is output. The switch control signal sw output from the decoder 46 is input to the switch 47. The switch 47 is a switch that is turned on / off in response to the switch control signal sw, and applies a drive signal from the drive signal generator 11 to the piezoelectric element 22 during the on period. Drive signals COM1 and COM2 from the printer controller 7 side are input to the switch 47. Further, the piezoelectric element 22 is connected to the output side of the switch 47. When the switch control signal sw is data [1], the switch 47 is turned on and the drive signal is applied to the piezoelectric element 22. When the switch control signal sw is data [0], the switch 47 is turned off, so that the drive signal is not applied to the piezoelectric element 22. Note that more detailed application control of the drive signal (drive pulse) will be described later.

FIG. 4 is a waveform diagram illustrating an example of the configuration of the drive signal in the present embodiment.
As shown in the figure, the first drive signal COM1 and the second drive signal COM2 are repeatedly generated at a unit period T defined by the latch signal LAT. The unit period T in this embodiment is divided into a total of three pulse periods by the latch signal LAT and the change signal CH (change pulse ch). Specifically, one unit period T includes a first period T1 defined by the latch signal LAT and the first change pulse ch1, and a second period defined by the first change pulse ch1 and the second change pulse ch2. It consists of three pulse periods of T2, and a third period T3 defined by the second change pulse ch2 and the next latch signal LAT. In the present embodiment, the first period T1 is the first pulse period in the unit period, and the combined period of the second period T2 and the third period T3 is the last pulse period in the unit period.

  The first drive signal COM1 is a drive signal including a first injection drive pulse P1 and a second injection drive pulse P2 (corresponding to the first drive waveform in the present invention) within the unit period T. Each of the first ejection drive pulse P1 and the second ejection drive pulse P2 has a drive voltage (potential difference from the lowest potential of the drive pulse to the highest potential) and a waveform in order to eject an amount of ink corresponding to the medium dot from the nozzle 34. It is a predetermined drive pulse. For this reason, the first ejection drive pulse P1 and the second ejection drive pulse P2 have the same waveform. The first injection drive pulse P1 is a drive pulse generated first in the unit cycle T, and the second injection drive pulse P2 is a drive pulse generated last in the unit cycle T. In addition, the second injection drive pulse P2 is transmitted in the middle of the contraction hold element p4 (described later) by the second change pulse ch2, and the front stage P2a (p1, p2, p3, and p4a) by the change signal CH (second change pulse ch2). ) And the rear stage P2b (p4b and p5). The front stage P2a is generated in the second period T2, and the rear stage P2b is generated in the third period T3. As will be described later, the front part P2a of the second ejection drive pulse P2 may be applied to the piezoelectric element 22 in combination with the rear part P4b of the micro-vibration drive pulse P4.

  The second drive signal COM1 is a drive signal including a third ejection drive pulse P3 and a fine vibration drive pulse P4 within the unit period T. The third ejection drive pulse P3 is a drive pulse that is first generated in the unit period T, and is a drive pulse in which a drive voltage, a waveform, and the like are determined so that an amount of ink corresponding to a small dot is ejected from the nozzle 34. . That is, the third ejection drive pulse P3 is a drive pulse that ejects an amount of ink smaller than the amount of ink ejected by the second ejection drive pulse P2. The slight vibration drive pulse P4 is a drive pulse in which a drive voltage, a waveform, and the like are determined so as to cause pressure fluctuation in the ink in the pressure chamber 32 to such an extent that the ink is not ejected from the nozzle 34. This fine vibration drive pulse P4 is used for a fine vibration operation in the case of non-ejection (non-recording) in which ink is not ejected in the unit period T. That is, when the fine vibration drive pulse P4 is applied to the piezoelectric element 22 during non-recording, the meniscus of the nozzle 34 is slightly vibrated and the ink is stirred. Thereby, ink thickening is suppressed. Further, the fine vibration drive pulse P4 is generated by a change signal CH (second change pulse ch2) in the middle of a fine vibration intermediate hold element p7 (described later) and a rear stage part P4a (p6 and p7a) and a rear stage part P4b (p7b, p8, p9 and p10). The front stage P4a is generated in the second period T2, and the rear stage P4b is generated in the third period T3. As will be described later, the rear stage portion P4b of the fine vibration drive pulse P4 may be applied to the piezoelectric element 22 in combination with the front stage portion P2a of the second ejection drive pulse P2. That is, the rear stage part P4b of the fine vibration drive pulse P4 corresponds to the waveform part in the present invention.

  Note that the number of drive signals and the types and number of drive pulses included in each drive signal are not limited to those illustrated. However, one of the drive signals includes at least a second injection drive pulse P2 corresponding to the first drive waveform generated at the end of the unit cycle T, and is one of the other drive signals. Includes a waveform part used in combination with the second injection driving pulse P2 at the end of the unit period T, that is, a rear stage part P4b of the micro-vibration driving pulse P4 in the present embodiment, for application of the present invention. Is required.

  FIG. 5A is a waveform diagram illustrating the configuration of the second ejection drive pulse P2, and FIG. 5B is a waveform diagram illustrating the configuration of the fine vibration drive pulse P4. FIG. 5C shows a fifth injection drive pulse P5 (second drive waveform) configured by combining the front stage P2a of the second injection drive pulse P2 and the rear stage P4b of the micro-vibration drive pulse P4. It is a wave form diagram explaining the structure of these. The first injection drive pulse P1 is the same as the waveform configuration of the second injection drive pulse P2 except that the first injection drive pulse P1 is not divided into a front-stage part and a rear-stage part. Further, since the third injection driving pulse has a well-known waveform, detailed description thereof is omitted.

  The second injection drive pulse P2 in the present embodiment includes an expansion element p1, an expansion hold element p2, a contraction element p3 (corresponding to the first potential changing portion in the present invention), a contraction hold element p4, and a return element p5. It consists of. The expansion element p1 corresponds to the reference volume of the pressure chamber 32 (the volume that serves as a reference for expansion or contraction), and the first expansion potential VH1 that is higher than the reference potential VB from the reference potential VB that is the base point of the potential change of the drive pulse. This is a waveform element in which the potential rises to the plus side (changes to the second polarity side) with a constant gradient that does not cause ink to be ejected until it corresponds to the first potential in the present invention. The expansion hold element p2 is a waveform element that maintains the first expansion potential VH1 that is the terminal potential of the expansion element p1 for a predetermined time. The contraction element p3 has a steep slope from the first expansion potential VH1 to the first contraction potential VL1 (corresponding to the second potential in the present invention) lower than the reference potential VB, and the potential drops to the minus side (GND side) (first side). 1 is a waveform element that causes pressure fluctuations to such an extent that ink can be ejected from the nozzles 34. The contraction hold element p4 is a waveform element that maintains the first contraction potential VL1 for a predetermined time. The contraction hold element p4 is divided into two parts, a front stage contraction hold element p4a and a rear stage contraction hold element p4b. The front stage contraction hold element p4a is a waveform part included in the front stage part P2a of the second injection drive pulse P2, and the rear stage contraction hold element p4b is a waveform part included in the rear stage part P2b of the second injection drive pulse P2. The return element p5 is an element that rises and recovers from the first contraction potential VL1 to the reference potential VB with a constant gradient that does not cause ink to be ejected.

  When the second ejection drive pulse P2 (both the front stage part p2a and the rear stage part p2b) is supplied to the piezoelectric element 22, first, the piezoelectric element 22 is contracted by the expansion element p1, and the pressure chamber 32 is caused accordingly. It expands from the reference volume corresponding to the reference potential VB to the maximum volume corresponding to the first expansion potential VH1. Thereby, the meniscus exposed to the nozzle 34 is drawn into the pressure chamber side. The expansion state of the pressure chamber 32 is kept constant throughout the application period of the expansion hold element p2. When the contraction element p3 is applied to the piezoelectric element 22 subsequent to the expansion hold element p2, the piezoelectric element 22 expands, so that the pressure chamber 32 contracts from the maximum volume to the first contraction potential VL1. Shrinks rapidly until The ink in the pressure chamber 32 is pressurized by the rapid contraction of the pressure chamber 32, and thereby, several pl to several tens pl of ink corresponding to the medium dot is ejected from the nozzle 34. The contraction state of the pressure chamber 32 is maintained over the application period of the contraction hold element p4, and then the return element p5 is applied to the piezoelectric element 22 so that the pressure chamber 32 is removed from the volume corresponding to the first contraction potential VL1. It returns to the reference volume corresponding to the reference potential VB. The second ejection drive pulse P2 is set so that the amount of ink droplets ejected is larger than that of the third ejection drive pulse P3. Mist is more likely to occur than when jetting. This mist is a very small ink droplet separated from the trailing end portion of the ink droplet (main droplet) ejected from the nozzle 34 and the satellite droplet following the main droplet. The mist contaminates the inside of the apparatus without reaching the recording medium and causes a malfunction due to adhesion to an easily charged member such as a recording head or an electric circuit. The countermeasure against this mist will be described later.

  The fine vibration drive pulse P4 in the present embodiment includes a first fine vibration contraction element p6, a fine vibration intermediate hold element p7, a second fine vibration contraction element p8 (corresponding to the second potential changing portion in the present invention), It consists of a fine vibration contraction hold element p9 and a fine vibration return element p10. The first slight vibration contraction element p6 is a waveform element in which the potential drops with a gentle gradient from the reference potential VB to the first contraction potential VL1 so that ink is not ejected from the nozzle 34. That is, the terminal potential of the first slight vibration contraction element p6 is aligned with the terminal potential of the contraction element p3 in the second ejection drive pulse P2. The slight vibration intermediate hold element p7 is a waveform element that maintains the first contraction potential VL1 for a predetermined time. The fine vibration intermediate hold element p7 is divided from the middle into two parts, a front fine vibration intermediate hold element p7a and a rear fine vibration intermediate hold element p7b. The front stage fine vibration intermediate hold element p7a is a waveform part included in the front stage part P4a of the fine vibration drive pulse P4, and the rear stage fine vibration intermediate hold element p7b is a waveform part included in the rear stage part P4b of the micro vibration drive pulse P4. is there. The second slight vibration contraction element p8 is such that ink is not ejected from the nozzle 34 from the first contraction potential VL1 to the second contraction potential VL2 (corresponding to the third potential in the present invention) lower than the first contraction potential VL1. It is a waveform element in which the potential drops with a gentle gradient. The fine vibration contraction hold element p9 is a waveform element that maintains the second contraction potential VL2 that is the terminal potential of the second microvibration contraction element p8 for a certain period of time. Further, the fine vibration return element p10 is a waveform element in which the potential rises with a sufficiently gentle gradient from the second contraction potential VL2 to the reference potential VB in an attitude in which ink is not ejected from the nozzle 34.

  When the micro-vibration driving pulse P4 configured in this way is applied to the piezoelectric element 22, first, the piezoelectric element 22 is expanded by the first micro-vibration contracting element p6, whereby the pressure chamber 32 is moved from the reference volume to the first volume. It gradually contracts to a volume corresponding to the contraction potential VL1. Due to the contraction of the pressure chamber 32, the ink in the pressure chamber 32 is pressurized to the extent that it is not ejected from the nozzle 34. The contraction state of the pressure chamber 32 is maintained over the application period of the fine vibration intermediate hold element p7. Subsequently, when the second microvibration contraction element p8 is applied to the piezoelectric element 22, the piezoelectric element 22 expands, whereby the pressure chamber 32 corresponds to the second contraction potential VL2 from the volume corresponding to the first contraction potential VL1. Slowly shrinks to the desired volume. The contraction state of the pressure chamber 32 is maintained over the application period of the fine vibration contraction hold element p9. Thereafter, the fine vibration return element p10 is applied to the piezoelectric element 22, and the pressure chamber 32 returns from the volume corresponding to the second contraction potential VL2 to the reference volume corresponding to the reference potential VB. With a series of volume fluctuations of the pressure chamber 32, a relatively gentle pressure vibration is generated in the pressure chamber 32, and the meniscus exposed to the nozzle 34 slightly vibrates due to the pressure fluctuation. Due to the slight vibration of the meniscus, the thickened ink in the vicinity of the nozzles 34 is dispersed, and as a result, thickening of the ink can be prevented.

  Next, the fifth ejection drive pulse P5 will be described. The fifth ejection drive pulse P5 is configured by combining a front stage part P2a of the second ejection drive pulse P2 and a rear stage part P4b of the fine vibration drive pulse P4. Thus, by combining the front stage part P2a and the rear stage part P4b, the front stage contraction hold element p4a of the second injection drive pulse P2 and the fine vibration intermediate hold element p7 of the fine vibration drive pulse P4 are a series of intermediate hold elements. p11 (corresponding to the maintenance unit in the present invention) is configured. The time width of the intermediate hold element p11 (the time from the end of the contraction element p3 to the second microvibration contraction element p8) Pw is, for example, the time from the start end of the contraction element p3 to the start end of the second microvibration contraction element p8 is 5 It is adjusted to be ˜15 μs.

  FIG. 6 is a schematic diagram for explaining a state in which ink is ejected from the nozzles 34 by the fifth ejection drive pulse P5. When the fifth ejection drive pulse P5 (a combination of the front stage P2a of the second ejection drive pulse P2 and the rear stage P4b of the micro-vibration drive pulse P4) is supplied to the piezoelectric element 22, first, the piezoelectric element is caused by the expansion element p1. Accordingly, the pressure chamber 32 expands from the reference volume corresponding to the reference potential VB to the maximum volume corresponding to the first expansion potential VH1. Thereby, as shown in FIG. 6A, the meniscus exposed to the nozzle 34 is drawn to the pressure chamber side. The expansion state of the pressure chamber 32 is kept constant throughout the application period of the expansion hold element p2. When the contraction element p3 is applied to the piezoelectric element 22 subsequent to the expansion hold element p2, the piezoelectric element 22 expands, whereby the pressure chamber 32 has a volume corresponding to the first contraction potential VL1 from the maximum volume ( Shrinks rapidly to an intermediate volume. The ink in the pressure chamber 32 is pressurized by the rapid contraction of the pressure chamber 32, and as shown in FIG. 6B, the central portion of the meniscus is pushed out to the ejection side (the lower side in the figure) and pushed out. The stretched part extends like a liquid column (ink column). Subsequently, the intermediate volume is maintained for the time Pw by the intermediate hold element p11. Thereby, the expansion of the piezoelectric element 22 is temporarily stopped. In the meantime, as shown in FIG. 6C, the ink injection at the center of the meniscus separates from the meniscus, and the separated portion is ejected from the nozzle 27 and flies. The ejected ink droplet is composed of a preceding main droplet Dm and a satellite droplet Ds which is separated from the trailing end portion in the traveling direction of the main droplet Dm and succeeds. Furthermore, a mist Ms finer than the satellite droplet Ds is also generated.

  Subsequently, the piezoelectric element 22 is expanded again by the second microvibration contraction element p8, whereby the volume of the pressure chamber 32 gradually decreases from the intermediate volume corresponding to the first contraction potential VL1 to the volume corresponding to the second contraction potential VL2. Shrink to. Thereby, as shown in FIG.6 (d), the whole meniscus is extruded in an injection direction. By the extrusion of the meniscus again, the mist Ms is absorbed by the meniscus. Also, some or all of the satellite droplets Ds are absorbed by the meniscus. For this reason, only the main droplet Dm or only the main droplet Dm and some satellite droplets Ds are ejected from the nozzle 34, and the occurrence of mist is suppressed. Thereafter, the contraction state of the pressure chamber 32 is maintained over the application period of the microvibration contraction hold element p9. Subsequently, the piezoelectric element 22 contracts by the microvibration return element p10, and the pressure chamber 32 becomes the second contraction potential VL2. To the reference volume corresponding to the reference potential VB.

  As described above, when ink is ejected using the fifth ejection driving pulse P5 that is a combination of the front stage P2a of the second ejection driving pulse P2 and the rear stage P4b of the fine vibration driving pulse P4, the ink (main The mist associated with the drop Dm) is reduced. Therefore, the fifth injection drive pulse P5 is used when mist suppression is required due to the relationship between the current unit cycle T and the next unit cycle T. Hereinafter, this point will be described.

FIG. 7 is a waveform diagram for explaining a drive pulse selection pattern.
In the printer 1 according to the present invention, based on the pixel data SI corresponding to the current unit cycle T (n) and the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1), the drive pulse for the piezoelectric element 22 is transmitted. It is characterized in that selective application control is performed. Here, in the printer 1 according to the present invention, it is possible to determine whether or not ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1) based on the first bit of the pixel data SI. In the present embodiment, the case where ink is ejected in the first period T1 of the unit cycle is when a small dot or a large dot is formed. Therefore, the first bit of pixel data corresponding to these dots is [1]. It is set to be. Specifically, pixel data corresponding to small dots is [10], and pixel data corresponding to large dots is [11]. In addition, since the case where ink is not ejected in the first period T1 of the unit cycle is when non-recording (fine vibration) or medium dots are formed, the first bit of pixel data corresponding to these dots is [0]. It is set to be. Specifically, pixel data corresponding to non-recording (fine vibration) is [00], and pixel data corresponding to medium dots is [01]. Therefore, “0” of the first bit of the pixel data is a value representing the first state indicating non-ejection (fine vibration) or medium dot (use of the second ejection driving pulse P2 or the fifth ejection driving pulse P5). “1” of the first bit of the pixel data is a value representing the second state indicating non-ejection (fine vibration) or medium dot (use of the second ejection driving pulse P2 or the fifth ejection driving pulse P5). Note that the bit of the pixel data may be inverted from that illustrated. In this case, the relationship between “0” and “1” and “first state” and “second state” also needs to be reversed from that illustrated in the present embodiment.

  First, in the case of non-printing in which ink is not ejected from a predetermined nozzle 34 (hereinafter, the predetermined nozzle 34 will be described) in the current unit cycle T (n), that is, in the current unit cycle T (n). A case where the corresponding pixel data SI is “00” will be described. In this case, the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0”, and the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “1”. At any time, the micro-vibration drive pulse P4 in the periods T2 and T3 in the second drive signal COM2 is selected and applied to the piezoelectric element 22 (FIG. 7A). Ink is not ejected during the micro-vibration operation by the micro-vibration drive pulse P4, so there is no possibility of mist generation. Therefore, regardless of whether or not ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1), the fine vibration drive pulse P4 is always selected and applied to the piezoelectric element 22 in the case of non-recording. Thus, a slight vibration operation is performed.

  When forming a small dot on the recording medium using the third ejection drive pulse P3 in the current unit period T (n), that is, when the pixel data SI corresponding to the current unit period T (n) is “10”. explain. In this case, the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0”, and the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “1”. At any time, the third ejection drive pulse P3 of the period T1 in the second drive signal COM2 is selected and applied to the piezoelectric element 22 (FIG. 7B). When ink is ejected by the third ejection drive pulse P3, since the amount of ink is smaller than when ink is ejected by the second ejection drive pulse P2, mist is less likely to occur. Therefore, regardless of whether or not ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1), the third ejection driving pulse P3 is always selected and the piezoelectric element is selected when recording small dots. 22, whereby the ink corresponding to the small dots is ejected from the nozzle 34.

  Next, a case where a medium dot is formed in the current unit cycle T (n), that is, a case where the pixel data SI corresponding to the current unit cycle T (n) is “01” will be described. In this case, when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0”, the second stage P2a of the second ejection drive pulse P2 in the period T2 in the first drive signal COM1, and the second In combination with the subsequent stage P4b of the micro-vibration driving pulse P4 in the period T3 in the driving signal COM2, it is applied to the piezoelectric element 22 as the fifth ejection driving pulse P5 (FIG. 7 (c)). Thereby, the ink corresponding to the medium dot is ejected from the nozzle 34 while the generation of mist is suppressed. On the other hand, when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “1”, the second ejection drive pulse P2 in the periods T2 and T3 in the first drive signal COM1 is selected and the piezoelectric element 22 is selected. (FIG. 7D). Thereby, ink corresponding to the medium dot is ejected from the nozzle 34. Even if mist is generated when ink is ejected by the second ejection drive pulse P2, the ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1), so that the mist is absorbed by the ink.

  A case where a large dot is formed in the current unit cycle T (n), that is, a case where the pixel data SI corresponding to the current unit cycle T (n) is “11” will be described. In this case, when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0”, the period in the first ejection drive pulse P1 and the first drive signal COM1 in the period T1 in the first drive signal COM1. The pre-stage part P2a of the second ejection drive pulse P2 of T2 and the post-stage part P4b of the micro-vibration drive pulse P4 of the period T3 in the second drive signal COM2 are sequentially applied to the piezoelectric element 22 (FIG. 7 (e)). As a result, ink corresponding to the medium dots is ejected from the nozzle 34 twice in succession, and these land on the pixel areas on the recording medium to form large dots. That is, a large dot is formed by the first ejection driving pulse P1 and the fifth ejection driving pulse P5. On the other hand, when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “1”, the first ejection drive pulse P1 in the period T1 in the first drive signal COM1 and the period in the first drive signal COM1. The second ejection drive pulse P2 of T2 and T3 is sequentially applied to the piezoelectric element 22 (FIG. 7 (f)). As a result, ink corresponding to the medium dots is ejected from the nozzle 34 twice in succession, and these land on the pixel areas on the recording medium to form large dots. That is, a large dot is formed by the first ejection drive pulse P1 and the second ejection drive pulse P2. Even if mist is generated when ink is ejected by the second ejection driving pulse P2, the ink is ejected in the first pulse period T1 of the next unit period T (n + 1), so that the mist is absorbed by the ink. The Therefore, a problem due to mist hardly occurs at this time.

Thus, in the printer 1 according to the present invention, the pixel data SI corresponding to the current unit period T (n) is the second ejection drive pulse P2 (first drive waveform) or the fifth ejection drive pulse P5 (second output). In the case of the data indicating the use of the driving waveform), when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0” (first state), the second ejection driving pulse The front stage P2a of P2 and the rear stage P4b of the fine vibration drive pulse P4 are combined and applied to the piezoelectric element 22 as the fifth ejection drive pulse P5, while the pixel data SI corresponding to the next unit cycle T (n + 1). When the first bit of “1” is “1” (second state), the second ejection drive pulse P2 is selected and applied to the piezoelectric element 22. Accordingly, it is possible to suppress the occurrence of mist while ensuring ejection stability regardless of whether or not ink is ejected in the first pulse period of the next unit cycle T (n + 1). That is, when ink is not ejected at the beginning of the next unit cycle T (n + 1), after the ink droplet is ejected at the end of the current unit cycle T (n), the first ink droplet is ejected after the next unit cycle T (n + 1). The time until injection is relatively long. In this case, generation of mist is suppressed by using the fifth injection drive pulse P5 generated at the end of the current unit cycle T (n). Further, since the time until the next ink droplet ejection is relatively long, the residual vibration caused by ejecting the ink droplet using the fifth ejection driving pulse P5 is attenuated until the next ink droplet ejection, It is suppressed that injection stability is impaired. On the other hand, when ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1), even if mist is generated during the ejection of ink by the second ejection drive pulse P2, the next unit cycle T (n + 1). The mist is absorbed by the ink ejected in the first pulse period T1. Therefore, in this case, by ejecting ink droplets using the second ejection drive pulse P2 in the current unit period T (n), ejection is suppressed without complicating residual vibration while suppressing generation of mist. Stabilize.
As described above, according to the present invention, it is possible to prevent the ejection from becoming unstable and to prevent malfunctions caused by mist, such as components in the printer (parts such as a drive motor, a drive gear, a drive belt, and a linear scale). It is possible to prevent contamination and malfunction.

  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.

FIG. 8 is a waveform diagram illustrating the configuration of the drive signal in the second embodiment of the present invention.
In the first embodiment, the fifth injection drive pulse P5 is illustrated by combining the front stage P2a of the second injection drive pulse P2 and the rear stage P4b of the fine vibration drive pulse P4. Not limited. In the present embodiment, the second injection drive pulse P2 is generated in the last pulse period T2 in one first drive signal COM1, and the fifth injection drive pulse in the last pulse period T2 in the other second drive signal COM2. P5 is generated. Then, the head controller 14 determines that the pixel data SI corresponding to the current unit period T (n) is the second ejection drive pulse P2 (first drive waveform) or the fifth ejection drive pulse P5 (second drive waveform). In the case of data indicating use, when the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “0” (first state), the period T2 in the second drive signal COM2 Is selected and applied to the piezoelectric element 22, while the first bit of the pixel data SI corresponding to the next unit cycle T (n + 1) is “1” (second state), The second ejection drive pulse P2 is selected and applied to the piezoelectric element 22. Accordingly, it is possible to suppress mist while ensuring ejection stability regardless of whether or not ink is ejected in the first pulse period T1 of the next unit cycle T (n + 1).

  The present invention is not limited to a printer, as long as it is a liquid ejecting apparatus capable of controlling the ejection of liquid by driving a pressure generating means by applying a drive waveform. The present invention can also be applied to a recording apparatus or a liquid ejecting apparatus other than the recording apparatus, such as a display manufacturing apparatus, an electrode manufacturing apparatus, or a chip manufacturing apparatus. In the display manufacturing apparatus, a solution of each color material of R (Red), G (Green), and B (Blue) is ejected from the color material ejecting head. Moreover, in an electrode manufacturing apparatus, a liquid electrode material is ejected from an electrode material ejection head. In the chip manufacturing apparatus, a bioorganic solution is ejected from a bioorganic ejecting head.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 6 ... Recording head, 7 ... Printer controller, 11 ... Drive signal production | generation part, 13 ... Print engine, 14 ... Head control part, 15 ... Actuator unit, 22 ... Piezoelectric element, 34 ... Nozzle, 45 ... Data storage 46, Decoder, 47 ... Switch

Claims (5)

A liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and ejects the liquid from the nozzle using the pressure fluctuation;
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
With
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes at least a second driving waveform that is generated at substantially the same timing as the first driving waveform at the end of the repetition period of the driving signal. And
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The second drive waveform includes the first potential changing unit, a maintaining unit that maintains the second potential, which is a terminal potential of the first potential changing unit, for a certain period of time, and a terminal potential of the maintaining element. A second potential changing section that changes in potential from the second potential to the third potential on the first polarity side;
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the second driving waveform is selected and applied to the pressure generating means, while the first bit of the injection control data corresponding to the next repetition period is in the second state. The liquid ejecting apparatus is characterized in that the first driving waveform is selected and applied to the pressure generating means. A liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and ejects the liquid from the nozzle using the pressure fluctuation;
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
With
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes a waveform portion that is generated at the end of the repetition period of the driving signal and used in combination with the first driving waveform.
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The waveform section includes a maintaining section that maintains the second potential for a certain period of time, and a first potential that changes from the second potential, which is a terminal potential of the maintaining section, to the third potential. 2 potential change portions,
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the waveform is combined and applied to the pressure generating means after the first potential change portion of the first drive waveform, and the injection corresponding to the next repetition period The liquid ejecting apparatus according to claim 1, wherein when the first bit of the control data is in the second state, the first driving waveform is selected and applied to the pressure generating means.   The head control means comprises storage means for storing the injection control data corresponding to the current repetition period and the first bit of the injection control data corresponding to the next repetition period. The liquid ejecting apparatus according to 1. A liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and ejects the liquid from the nozzle using the pressure fluctuation;
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
A control method for a liquid ejecting apparatus comprising:
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes at least a second driving waveform that is generated at substantially the same timing as the first driving waveform at the end of the repetition period of the driving signal. And
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The second drive waveform includes the first potential changing unit, a maintaining unit that maintains the second potential, which is a terminal potential of the first potential changing unit, for a certain period of time, and a terminal potential of the maintaining element. A second potential changing section that changes in potential from the second potential to the third potential on the first polarity side;
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the second driving waveform is selected and applied to the pressure generating means, while the first bit of the injection control data corresponding to the next repetition period is in the second state. A control method for the liquid ejecting apparatus, wherein the first drive waveform is selected and applied to the pressure generating means. A liquid ejecting head that causes pressure fluctuation in the liquid in the pressure chamber by driving the pressure generating means, and ejects the liquid from the nozzle using the pressure fluctuation;
Drive signal generating means for repeatedly generating a plurality of drive signals including a drive waveform for driving the pressure generating means simultaneously;
Selective application control of drive waveform to the pressure generating means based on ejection control data composed of a plurality of bits indicating which of the drive waveforms included in each of the drive signals is used to eject the liquid or not to eject the liquid Head control means for performing,
A control method for a liquid ejecting apparatus comprising:
One drive signal among the drive signals includes at least a first drive waveform generated at the end of a repetition period of the drive signal,
One of the other driving signals among the driving signals includes a waveform portion that is generated at the end of the repetition period of the driving signal and used in combination with the first driving waveform.
The first drive waveform includes a first potential change in which liquid is ejected from the nozzle by continuously changing the potential to the first polarity side with a constant potential gradient from the first potential to the second potential. Part
The waveform section includes a maintaining section that maintains the second potential for a certain period of time, and a first potential that changes from the second potential, which is a terminal potential of the maintaining section, to the third potential. 2 potential change portions,
The first bit of the ejection control data indicates the first state indicating the use of the first drive waveform or the second drive waveform, or indicates the non-ejection without performing liquid ejection, or the first drive waveform. Or any of the second states indicating use of a drive waveform other than the second drive waveform,
In the case where the injection control data corresponding to the current repetition cycle is data indicating the use of the first drive waveform or the second drive waveform, the head control unit is configured to store the injection control data corresponding to the next repetition cycle. When the first bit is in the first state, the waveform is combined and applied to the pressure generating means after the first potential change portion of the first drive waveform, and the injection corresponding to the next repetition period A control method for a liquid ejecting apparatus, wherein when the first bit of control data is in a second state, the first drive waveform is selected and applied to the pressure generating means.

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