JP3636129B2 - Ink jet recording apparatus and driving method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus having a recording head capable of ejecting ink droplets by operation of a piezoelectric vibrator, and a driving method thereof.
[0002]
[Prior art]
2. Description of the Related Art Inkjet recording apparatuses such as printers, plotters, and facsimiles record dots by ejecting ink droplets from a recording head and landing the ink droplets on a printing recording medium such as recording paper or a printing film. Some recording heads used in this recording apparatus use a piezoelectric vibrator (PZT) as a pressure generation source. The recording head expands or contracts the pressure chamber by deformation of the piezoelectric vibrator, and causes pressure fluctuation in the ink in the pressure chamber. Then, ink droplets are ejected from the nozzle openings using the pressure fluctuation of the ink.
The above-described piezoelectric vibrator has a deformation amount determined according to a supplied voltage value, and has high response to a change in voltage value. For this reason, the ink pressure can be controlled with high accuracy by appropriately setting the waveform shape of the drive signal supplied to the piezoelectric vibrator, and ink droplets having a desired amount and a desired speed can be ejected.
[0003]
Also, with this recording head, the volume of the pressure chamber is maintained in an intermediate state in a steady state and the volume is changed to either the expansion side or the contraction side in order to meet the demands for higher image quality and higher recording speed. I am trying to do it. For this reason, a bias voltage is normally supplied to the piezoelectric vibrator. In other words, in the normal state, the vibrator potential of the piezoelectric vibrator is adjusted to the drive potential set between the minimum potential and the maximum potential.
[0004]
[Problems to be solved by the invention]
However, the piezoelectric vibrator has a life, and if a high load is applied, the life is shortened. For this reason, in the conventional configuration in which the bias voltage is supplied in a normal state, the bias voltage is continuously supplied to the piezoelectric vibrator for a long time, which may shorten the life of the piezoelectric vibrator. is there.
[0005]
The present invention has been made in view of such circumstances, and an object thereof is to provide an ink jet recording apparatus suitable for protecting a piezoelectric vibrator and a driving method thereof.
[0006]
[Means for Solving the Problems]
The present invention has been proposed to achieve the above object, and the recording medium according to claim 1 includes a piezoelectric vibrator capable of causing a pressure fluctuation in the pressure chamber and a nozzle opening communicating with the pressure chamber. Head, drive signal generating means for repeatedly generating a series of drive signals including a plurality of waveform elements for each recording period, and waveform element supplying means for supplying waveform elements selected according to gradation data to the piezoelectric vibrator In an ink jet recording apparatus capable of multi-tone recording,
A recording state determination unit that determines the presence or absence of recording based on gradation data in the next recording cycle and obtains determination data, and a transducer potential adjustment unit that adjusts the transducer potential in the current recording cycle,
The waveform element generated by the drive signal generating means includes a plurality of ejection waveform elements that are waveform elements for ejecting ink droplets and whose start / end potential is set to a drive potential higher than the base potential,
The vibrator potential adjusting means adjusts the vibrator potential to the driving potential at the end of the current recording cycle when the determination data of the next recording cycle indicates recording and the vibrator potential at the end of the current recording cycle when indicating non-recording. The ink jet recording apparatus is characterized in that is adjusted to a base potential.
[0007]
According to the first aspect of the present invention, when both the current recording period and the next recording period are “non-recording”, the vibrator potential adjusting means adjusts the vibrator potential to the base potential at the end of the current recording period. . When both the current recording period and the next recording period are “recording”, the vibrator potential adjusting means adjusts the vibrator potential to the drive potential at the end of the current recording period.
In addition, when the current recording cycle is “non-recording” and the next recording cycle is “recording”, the vibrator potential adjusting unit adjusts the vibrator potential to the driving potential in the current recording period. Thereby, the starting end potential of the ejection waveform element and the vibrator potential are aligned at the same potential in the next recording cycle. Further, when the current recording cycle is “recording” and the next recording cycle is “non-recording”, the vibrator potential adjusting means adjusts the vibrator potential to the base potential at the end of the current recording period.
[0008]
Therefore, when non-recording continues, the vibrator potential is adjusted to the base potential, so the burden on the piezoelectric vibrator is reduced. Further, when recording continues, the vibrator potential becomes constant at the drive potential during the period when the ejection waveform element is not supplied, so that the burden on the piezoelectric vibrator due to high and low potentials is eliminated in a short time. Furthermore, when the recording state changes in the next recording cycle, the potential is adjusted in the current recording cycle, so that the waveform element can be smoothly supplied to the piezoelectric vibrator in the next recording cycle, Therefore, the potential on the piezoelectric vibrator is reduced.
As a result, even if high-frequency driving is performed by a waveform element having a high start / end potential, the burden on the piezoelectric vibrator is reduced, and the piezoelectric vibrator can be protected.
[0009]
According to a second aspect of the present invention, the waveform element generated by the drive signal generating means includes a first connection element that increases the potential from the base potential to the drive potential, and a second element that decreases the potential from the drive potential to the base potential. Including linking elements,
The vibrator potential adjusting means includes a waveform element supply means, and the vibrator potential is adjusted by selectively supplying a waveform element to the piezoelectric vibrator in accordance with determination data of a next recording cycle. 1. An ink jet recording apparatus according to 1.
[0010]
According to a third aspect of the present invention, the drive signal generating means generates at least one ejection waveform element between the first connection element and the second connection element. An ink jet recording apparatus.
[0011]
According to a fourth aspect of the present invention, in the driving signal generating unit, the second connection element is generated after the last ejection waveform element in the recording period. Inkjet recording apparatus.
[0012]
According to a fifth aspect of the present invention, the drive signal generating means generates the first connecting element between adjacent discharge waveform elements. Inkjet recording apparatus.
[0013]
According to a sixth aspect of the present invention, the drive signal generating means changes the potential between the terminal potential of the ejection waveform element and the first terminal potential of the first connecting element, but does not supply the connecting element to the piezoelectric vibrator. 6. The ink jet recording apparatus according to claim 5, wherein the ink jet recording apparatus is generated between the discharge waveform element and the first connection element.
[0014]
The waveform element selecting means selects the first connecting element and the second connecting element when both the current recording period and the next recording period indicate non-recording, and the ink in the pressure chamber The ink jet recording apparatus according to claim 2, wherein the ink jet recording apparatus is agitated.
[0015]
According to an eighth aspect of the present invention, the vibrator potential adjusting means includes a resistance element and an adjustment switch that selectively connects the piezoelectric vibrator to a drive potential supply source or a base potential supply source via the resistance element. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is constituted by a device.
[0016]
The ink jet recording according to any one of claims 1 to 8, wherein a plurality of ejection waveform elements generated by the drive signal generating means have the same waveform shape. Device.
[0017]
According to a tenth aspect of the present invention, a driving signal including a plurality of waveform elements is repeatedly generated for each recording period, a waveform element is selected according to gradation data, and the selected waveform element is selected as a piezoelectric vibrator of a recording head. In a driving method of an ink jet recording apparatus that performs multi-gradation recording by supplying to
The waveform element is a waveform element for discharging ink droplets, and includes a plurality of discharge waveform elements in which a start / end potential is set to a drive potential higher than a base potential,
Based on the gradation data in the current recording cycle and the judgment data in the next recording cycle, the vibrator potential at the end of the current recording cycle is adjusted to the base potential when the next recording cycle is not recorded, and the next recording cycle In the case of recording, the ink jet recording apparatus is driven by adjusting the driving potential.
[0018]
The invention according to claim 10 has the same action as that of claim 1 described above. Therefore, even in the tenth aspect of the present invention, even when high-frequency driving is performed using a waveform element having a high start / end potential, the burden on the piezoelectric vibrator is reduced, and the piezoelectric vibrator can be protected.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of an ink jet printer to which the present invention is applied.
[0020]
The illustrated printer includes a printer controller 1 and a print engine 2. The printer controller 1 includes an interface 3 (hereinafter referred to as an external I / F 3) that receives print data from a host computer (not shown), a RAM 4 that stores various data, a routine for various data processing, and the like. , A control unit 6 composed of a CPU or the like, an oscillation circuit 7 that generates a clock signal (CK), a drive signal generation circuit 9 that generates a drive signal (COM) to be supplied to the recording head 8, and a dot An interface 10 (hereinafter referred to as an internal I / F 10) for transmitting pattern data, drive signals, and the like to the print engine 2 is provided.
[0021]
The external I / F 3 receives print data including, for example, any one or more of character code, graphic function, and image data from a host computer or the like. The external I / F 3 outputs a busy signal (BUSY), an acknowledge signal (ACK), and the like to the host computer.
[0022]
The RAM 4 is used as a reception buffer, an intermediate buffer, an output buffer, a work memory (not shown), and the like. Print data from the host computer received by the external I / F 3 is temporarily stored in the reception buffer. The intermediate buffer stores intermediate code data converted into an intermediate code by the control unit 6. Recording data and determination data are developed in the output buffer. The ROM 5 stores various control routines executed by the control unit 6, font data and graphic functions, various procedures, and the like.
[0023]
The drive signal generation circuit 9 is a kind of drive signal generation means in the present invention, and based on waveform control information from the control unit 6 (waveform generation control means), as shown in FIG. 3, a plurality of pulse signals PS1 to PS6. A series of drive signals (COM) including are generated. Then, the drive signal generation circuit 9 repeatedly generates this drive signal every recording cycle T. This drive signal will be described in detail later.
[0024]
The control unit 6 also functions as a recording control unit. That is, the control unit 6 reads the print data in the reception buffer, converts it into an intermediate code, and stores this intermediate code data in the intermediate buffer. Further, the control unit 6 analyzes the intermediate code data read from the intermediate buffer, and develops the intermediate code data into recording data for each dot by referring to the font data and graphic functions in the ROM 5.
[0025]
The recording data of this embodiment is composed of gradation data in which one dot is 2 bits. The gradation data includes, for example, gradation data [00] indicating non-recording (fine vibration within printing), gradation data [01] indicating recording by small dots, and gradation data [01] indicating recording by medium dots. 10] and gradation data [11] indicating recording by large dots. Therefore, with this configuration, each dot can be recorded with four gradations.
[0026]
At the time of development of the recording data, the control unit 6 also functions as a recording state determination unit of the present invention, and determines the presence / absence of recording based on the gradation data of the next dot (that is, the next recording period T), and the determination data To get. Then, the determination data is added to the gradation data of the dot (that is, the current recording cycle T). Since this determination data indicates the presence or absence of recording, it is composed of 1-bit data. For example, the determination data is [0] in the case of non-recording, and the determination data is [1] in the case of recording any of small dots to large dots.
[0027]
Accordingly, the output data output to the recording head 8 is a total of 3-bit data including 2-bit gradation data and 1-bit determination data. For example, when the gradation data of the dot indicates large dot recording and the gradation data of the next dot indicates non-recording, the output data is [110], and the gradation data of the dot is small dot recording. When the gradation data of the next dot indicates non-recording, the output data is [010]. When the tone data of the dot indicates non-recording and the tone data of the next dot indicates medium dot recording, the output data is [001].
[0028]
When recording data and determination data corresponding to one line (one pass corresponding to one main scanning) are developed in the output buffer, the output data (recording data and determination data) for one line is internally stored. Serial transmission is performed to the recording head 8 via the I / F 10. When one line of output data is output from the output buffer, the contents of the intermediate buffer are erased, and the control unit 6 expands the next line of data.
[0029]
The control unit 6 constitutes a part of the timing signal generating means, and supplies a latch signal (LAT) and a channel signal (CH) to the recording head 8 through the internal I / F 10. These latch signals and channel signals define the supply start timing of the plurality of pulse signals PS1 to PS6 constituting the drive signal. In other words, the latch signal and the channel signal serve as a trigger that defines the generation timing of the timing signal supplied from the control logic 48 to the decoder 47.
[0030]
Specifically, as shown in FIG. 3, the latch signal defines the supply start timing of the first pulse signal PS1, and the first channel signal CH1 defines the supply start timing of the second pulse signal PS2. The second channel signal CH2 defines the supply start timing of the third pulse signal PS3, and the third channel signal CH3 defines the supply start timing of the fourth pulse signal PS4. Further, the fourth channel signal CH4 defines the supply start timing of the fifth pulse signal PS5, and the fifth channel signal CH5 defines the supply start timing of the sixth pulse signal PS6.
As will be described later, the third pulse signal PS3 in the present embodiment is not supplied to the piezoelectric vibrator 21. For this reason, it can be said that the second channel signal CH2 defines the drive signal supply cutoff timing.
[0031]
The print engine 2 includes a carriage mechanism 11, a paper feed mechanism 12, and a recording head 8.
[0032]
The carriage mechanism 11 includes a carriage to which the recording head 8 is attached and a pulse motor that moves the carriage via a timing belt or the like, and moves the recording head 8 in the main scanning direction. The paper feed mechanism 12 includes a paper feed motor, a paper feed roller, and the like, and sequentially feeds recording paper (a type of print recording medium) to perform sub-scanning.
[0033]
Next, the recording head 8 will be described in detail. First, the structure of the recording head 8 will be described. The recording head 8 illustrated in FIG. 2 is a recording head 8 to which a so-called flexural vibration mode piezoelectric vibrator 21 is attached, and is schematically composed of a flow path unit 22 and an actuator unit 23.
[0034]
The flow path unit 22 includes a supply port forming substrate 26 having a through hole that becomes an ink supply port 24 and a through hole that becomes a part of the first nozzle communication hole 25, and a through hole and a second nozzle that become a common ink chamber 27. An ink chamber forming substrate 29 having a through hole serving as a communication hole 28 and a plurality of (for example, 64) nozzle openings 30 are configured by a nozzle plate 31 having a sub-scanning direction. Then, the nozzle plate 31 is disposed on the front surface side (lower side in FIG. 2) of the ink chamber forming substrate 29, and the supply port forming substrate 26 is disposed on the rear surface side (upper side). The chamber forming substrate 29 and the nozzle plate 31 are integrated.
[0035]
The actuator unit 23 includes a first lid member 32 functioning as an elastic plate, a pressure chamber forming substrate 34 having a through hole serving as a pressure chamber 33, a through hole serving as a supply side communication hole 35, and a first nozzle communication hole. 25, the second lid member 36 having a through hole that is a part of 25, and the piezoelectric vibrator 21. Then, the first lid member 32 is disposed on the back surface of the pressure chamber forming substrate 34 and the second lid member 36 is disposed on the front surface, and the pressure chamber forming substrate is formed by the first lid member 32 and the second lid member 36. 34 is integrated.
[0036]
The piezoelectric vibrator 21 is formed on the back side of the first lid member 32. The illustrated piezoelectric vibrator 21 is in the flexural vibration mode as described above, and an elastic plate (first lid member 32) is provided so that the volume of the pressure chamber 33 is reduced by contracting in a direction orthogonal to the electric field by charging. The elastic plate is deformed so as to increase the volume of the pressure chamber 33 by being deformed and extending in a direction orthogonal to the electric field by electric discharge. The piezoelectric vibrator 21 includes a common electrode 37 formed on the back surface of the first lid member 32, a piezoelectric layer 38 formed in a stacked state on the back surface of the common electrode 37, and a back surface of each piezoelectric layer 38. The drive electrodes 39 are formed, and a plurality (for example, 64) of the pressure chambers 33 are formed corresponding to the pressure chambers 33.
The piezoelectric vibrator 21 behaves in the same way as a capacitor, and retains the potential immediately before the interruption when the supply of the drive signal is interrupted.
[0037]
In the recording head 8 having such a configuration, a series of ink flow paths from the common ink chamber 27 through the pressure chamber 33 to the nozzle opening 30 is formed for each nozzle opening 30. Then, when the piezoelectric vibrator 21 is charged or discharged, the corresponding pressure chamber 33 contracts or expands, and pressure fluctuation occurs in the ink in the pressure chamber 33.
[0038]
Ink droplets can be ejected from the nozzle openings 30 by controlling the ink pressure. For example, when the pressure chamber 33 having a steady volume is once expanded and then rapidly contracted, an ink droplet is ejected from the nozzle opening 30. Further, when the pressure chamber 33 is contracted and expanded to such an extent that no ink droplet is ejected, the meniscus (the free surface of the ink exposed at the nozzle opening 30) vibrates slightly. The ink in the vicinity of the nozzle opening 30 is agitated by the slight vibration of the meniscus, so that thickening of the ink in the portion can be prevented.
[0039]
Next, the electrical configuration of the recording head 8 will be described.
[0040]
As shown in FIG. 1, the recording head 8 includes a shift register circuit including a first shift register 41, a second shift register 42, and a third shift register 43, a first latch circuit 44, a second latch circuit 45, And a third latch circuit 46, a decoder 47, a control logic 48, a level shifter 49, a switch circuit 50, and the piezoelectric vibrator 21. A plurality of shift registers 41 to 43, latch circuits 44 to 46, level shifter 49, switch circuit 50, and piezoelectric vibrator 21 are provided corresponding to the nozzle openings 30 of the recording head 8.
[0041]
The recording head 8 ejects ink droplets based on output data (recording data and determination data) from the printer controller 1. That is, prior to ejection of ink droplets, first, output data from the printer controller 1 is serially transmitted to the shift registers 41 to 43 in synchronization with the clock signal (CK) from the oscillation circuit 7. This output data is composed of an upper bit group of print data for all nozzle openings 30..., A lower bit group of print data, and a determination data group.
[0042]
In this embodiment, since the upper bit group of the recording data, the lower bit group of the recording data, and the determination data group are sent to the recording head 8 in this order, first, the upper bit group of the recording data is set in the first shift register 41. Is done.
When the upper bit group of the recording data is set in the first shift register 41 for all the nozzle openings 30..., The lower bit group of the recording data is subsequently set in the first shift register 41. Along with the setting of the lower bit group of the recording data, the upper bit group of the recording data is shifted and set in the second shift register 42.
Further, when the lower bit group of the recording data is set in the first shift register 41 for all the nozzle openings 30..., The determination data group is subsequently set in the first shift register 41. With the determination data group set, the upper bit group of the recording data is shifted and set in the third shift register 43, and the lower bit group of the recording data is shifted and set in the second shift register 42.
[0043]
A first latch circuit 44 is electrically connected to the first shift register 41, a second latch circuit 45 is electrically connected to the second shift register 42, and a third latch circuit 46 is connected to the third shift register 43. Are electrically connected. When a latch signal (LAT) from the printer controller 1 is input to each of the latch circuits 44 to 46, the third latch circuit 46 latches the upper bits of the gradation data in the current recording cycle T, and the second latch circuit 45 latches the lower bits of the gradation data in the current recording cycle T, and the first latch circuit 44 latches the determination data in the next recording cycle T.
That is, the third latch circuit 46 and the second latch circuit 45 function as gradation data holding means for holding gradation data in the current recording cycle T, and the first latch circuit 44 holds determination data in the next recording cycle T. It functions as determination data holding means.
[0044]
The data latched in the first latch circuit 44, the second latch circuit 45, and the third latch circuit 46 are input to the decoder 47, respectively. The decoder 47 functions as a waveform element selection unit, and generates selection data for selecting each of the pulse signals PS1 to PS6 from the gradation data in the current recording cycle T and the determination data in the next recording cycle T. That is, the decoder 47 translates (decodes) based on the data of a total of 3 bits latched by the latch circuits 44 to 46 to generate 6-bit selection data.
[0045]
Each bit of the selection data corresponds to each pulse signal PS1 to PS6. In the present embodiment, the most significant bit (bit 5) corresponds to the first pulse signal PS1, the fifth bit (bit 4) corresponds to the second pulse signal PS2, and the fourth bit (bit 3) corresponds to the first pulse signal PS1. This corresponds to the 3-pulse signal PS3. Similarly, the third bit (bit 2) corresponds to the fourth pulse signal PS4, the second bit (bit 1) corresponds to the fifth pulse signal PS5, and the least significant bit (bit 0) corresponds to the sixth pulse. It corresponds to the signal.
[0046]
The decoder 47 also receives a timing signal from the control logic 48. The control logic 48 functions as a timing signal generating means together with the control unit 6 and generates a timing signal in synchronization with the input of the latch signal (LAT) and the channel signal (CH) as described above.
[0047]
The 6-bit selection data translated by the decoder 47 is sequentially input to the level shifter 49 from the upper bit side at the timing specified by the timing signal. The level shifter 49 functions as a voltage amplifier. When the selection data is [1], the level shifter 49 outputs an electric signal boosted to a voltage that can drive the switch circuit 50, for example, a voltage of about several tens of volts.
[0048]
The selection data [1] boosted by the level shifter 49 is supplied to the switch circuit 50. A drive signal (COM) is supplied from the drive signal generation circuit 9 to the input side (upstream side) of the switch circuit 50, and the piezoelectric vibrator 21 is connected to the output side (downstream side) of the switch circuit 50. Has been.
[0049]
The selection data controls the operation of the switch circuit 50. That is, during the period when the selection data applied to the switch circuit 50 is [1], the drive signals (pulse signals PS1 to PS6) are supplied to the piezoelectric vibrator 21, and the vibrator of the piezoelectric vibrator 21 is responded to this drive signal. The potential (that is, the electrode potential on the side to which the drive signal is supplied) changes. On the other hand, during the period when the selection data applied to the switch circuit 50 is [0], the level shifter 49 does not output an electrical signal for operating the switch circuit 50, and no drive signal is supplied to the piezoelectric vibrator 21. Accordingly, the pulse signals PS1 to PS6 in which [1] is set as selection data are selectively supplied to the piezoelectric vibrator 21.
[0050]
In this embodiment, the decoder 47, the control logic 48, the level shifter 49, and the switch circuit 50 function as waveform element supply means (a kind of vibrator potential adjustment means of the present invention). Each pulse signal PS1 to PS6 (that is, each waveform element to be described later) is selectively supplied to the piezoelectric vibrator 21 based on the selection data generated by.
[0051]
Next, the selection operation of the drive signal (COM) generated by the drive signal generation circuit 9 and the pulse signals PS1 to PS6 constituting this drive signal will be described.
[0052]
First, the drive signal will be described. As described above, the drive signal illustrated in FIG. 3 includes the first pulse signal PS1, the second pulse signal PS2, the third pulse signal PS3, the fourth pulse signal PS4, the fifth pulse signal PS5, and the sixth pulse signal. It is a series of signals composed of PS6. The first pulse signal PS1 is generated in the first period t1 within the recording period T, the second pulse signal PS2 is generated in the second period t2, and the third pulse signal PS3 is generated in the third period t3. Further, the fourth pulse signal PS4 is generated in the fourth period t4, the fifth pulse signal PS5 is generated in the fifth period t5, and the sixth pulse signal PS6 is generated in the sixth period t6.
[0053]
The first pulse signal PS1 includes a front constant potential element P1 that is constant at the intermediate potential Vc, an expansion element P2 that lowers the potential with a constant gradient that does not cause ink droplets to be ejected from the intermediate potential Vc to the lowest potential VL, and the lowest potential VL. From the maximum potential VH, the expansion hold element P3 that holds the maximum potential VH for a predetermined time, the discharge element P4 that rapidly increases the potential from the minimum potential VL to the maximum potential VH, the vibration suppression hold element P5 that holds the maximum potential VH for a predetermined time It includes a damping element P6 that drops the potential with a constant gradient that does not cause ink droplets to be ejected to the intermediate potential Vc, and a rear constant potential element P7 that is constant at the intermediate potential Vc. Among these waveform elements, the expansion element P2, the expansion hold element P3, the discharge element P4, the vibration suppression hold element P5, and the vibration suppression element P6 are first discharge waveform elements for discharging a predetermined amount of ink droplets. Configure DP1.
[0054]
Note that the lowest potential VL is the lowest potential in the drive signal and is a kind of the base potential of the present invention. In the present embodiment, this minimum potential VL is set to a ground potential (ground potential) suitable for protecting the piezoelectric vibrator 21. Further, the intermediate potential Vc is a start / end potential of the ejection waveform element, and is a kind of drive potential of the present invention.
[0055]
The second pulse signal PS2 also includes a front constant potential element P8, an expansion element P9, an expansion hold element P10, a discharge element P11, a vibration suppression hold element P12, a vibration suppression element P13, and a rear constant potential element P14. The second discharge waveform element DP2 is configured by the elements from the element P9 to the damping element P13. The elements from the expansion element P9 to the damping element P13 are set to the same potential and time width as the elements P2 to P6 included in the first pulse signal PS1. Accordingly, the first ejection waveform element DP1 included in the first pulse signal PS1 and the second ejection waveform element DP2 included in the second pulse signal PS2 have the same waveform shape.
[0056]
The third pulse signal PS3 includes a front constant potential element P15 that is constant at the intermediate potential Vc, a connection element P16 that drops steeply from the intermediate potential Vc to the lowest potential VL, and a rear constant potential that is constant at the lowest potential VL. Element P17. The connection element P16 has the terminal potential of the second pulse signal PS2 (that is, the second ejection waveform element DP2) generated immediately before and the beginning of the fourth pulse signal PS4 (the first connection element P19) generated immediately after. It is an element for connecting a potential. The connection element P16, the front side constant potential element P15, and the rear side constant potential element P17 are not supplied to the piezoelectric vibrator 21. Therefore, the gradient is set as steep as possible for the connection element P16, and the generation period is set as short as possible for the front side constant potential element P15 and the back side constant potential element P17. The generation interval of the signal PS2 and the fourth pulse signal PS4 is made as short as possible.
[0057]
The fourth pulse signal PS4 includes a constant front-side constant potential element P18 at the lowest potential VL, a first connection element P19 that increases the potential with a constant gradient from the lowest potential VL to the intermediate potential Vc, and a constant rear side at the intermediate potential Vc. A constant potential element P20 is included.
The first connecting element P19 is a waveform element for raising the vibrator potential from the lowest potential VL to the intermediate potential Vc, and the gradient has a small burden on the piezoelectric vibrator 21 and ink droplets are not ejected. The pressure fluctuation is set to such a degree that the ink in the pressure chamber 33 is excited.
[0058]
The fifth pulse signal PS5 includes a front constant potential element P21, an expansion element P22, an expansion hold element P23, a discharge element P24, a vibration suppression hold element P25, a vibration suppression element P26, and a rear constant potential element P27. The third discharge waveform element DP3 is configured by the elements from P22 to the damping element P26. Each element from the expansion element P22 to the damping element P26 is set to the same potential and time width as each element included in the first pulse signal PS1 and the second pulse signal PS2. Therefore, the third discharge waveform element DP3, the first discharge waveform element DP1, and the second discharge waveform element DP2 have the same waveform shape.
[0059]
The sixth pulse signal PS6 includes a constant constant potential element P28 having a constant intermediate potential Vc, a second connecting element P29 for decreasing the potential from the intermediate potential Vc to the lowest potential VL with a constant gradient, and a constant rear side having the lowest potential VL. A constant potential element P30 is included. Therefore, in this drive signal, the second coupling element P29 is generated after the third ejection waveform element DP3 which is the last ejection waveform element in the recording cycle T. Further, a third discharge waveform element DP3 is generated between the second connecting element P29 and the first connecting element P19.
The second connecting element P29 is a waveform element for lowering the vibrator potential from the intermediate potential Vc to the lowest potential VL. The gradient is set to such an extent that the pressure on the piezoelectric vibrator 21 is small and pressure fluctuations that do not eject ink droplets can occur in the ink in the pressure chamber 33, as in the first connecting element P19. ing.
[0060]
In this drive signal, when the ejection waveform elements (DP1 to DP3) are supplied to the piezoelectric vibrator 21, a predetermined amount of ink is ejected from the nozzle opening 30. That is, the pressure chamber 33 expands from the steady volume defined by the intermediate potential Vc to the maximum volume defined by the lowest potential VL by supplying the expansion elements (P2, P9, P22), and the ink in the pressure chamber 33 is decompressed. The pressure oscillation is excited. Next, when the expansion hold element (P3, P10, P23) is supplied, the expansion state of the pressure chamber 33 is maintained, and the ink pressure in the pressure chamber 33 changes to a positive pressure during that time. The ejection elements (P4, P10, P24) are supplied at the timing when the ink pressure becomes positive, and the volume of the pressure chamber 33 rapidly contracts to the minimum volume defined by the maximum potential VH. As a result, the ink in the pressure chamber 33 is pushed out, and a predetermined amount of ink droplets are ejected from the nozzle opening 30. Thereafter, when the vibration damping hold element (P5, P11, P25) is supplied, the contracted state of the pressure chamber 33 is maintained, and the ink pressure fluctuates during this maintenance period. And the damping element (P6, P12, P26) is supplied at the timing when the ink pressure in the pressure chamber 33 becomes positive. By supplying this damping element, the pressure chamber 33 expands and acts to cancel the fluctuation of the ink pressure.
[0061]
In this drive signal, when the first coupling element P19 is supplied to the piezoelectric vibrator 21, the vibrator potential rises from the lowest potential VL to the intermediate potential Vc. As the vibrator potential increases, the volume of the pressure chamber 33 expands from the minimum volume defined by the lowest potential VL to the steady volume defined by the intermediate potential Vc. By this expansion, the ink in the pressure chamber 33 is slightly reduced to such an extent that ink droplets are not ejected, and the pressure vibration is excited.
On the other hand, when the second connecting element P29 is supplied to the piezoelectric vibrator 21, the vibrator potential drops from the intermediate potential Vc to the lowest potential VL. As the vibrator potential decreases, the volume of the pressure chamber 33 contracts from the steady volume to the minimum volume. By this contraction, the ink in the pressure chamber 33 is slightly pressurized so that ink droplets are not ejected, and the pressure vibration is excited.
[0062]
In this embodiment, the gradation data of the dot (current recording cycle T) indicates non-recording, and the determination data of the next dot (next recording cycle T) indicates non-recording, that is, output data [000]. In this case, the waveform element supplying means (vibrator potential adjusting means) supplies the first connecting element P19 and the second connecting element P29 to the piezoelectric vibrator 21 in the current recording cycle T. As a result, in the current recording period T, pressure vibration that does not cause ink droplets to be ejected is excited in the ink in the pressure chamber 33, the meniscus is vibrated slightly by this pressure vibration, and the viscosity of the ink near the nozzle opening 30 is increased. Is prevented. In this case, the vibrator potential at the end of the current recording cycle T is adjusted to the lowest potential VL.
[0063]
Further, when the tone data of the dot indicates non-recording and the determination data of the next dot indicates recording, that is, when the output data is [001], the waveform element supply means is the first in the current recording cycle T. The connecting element P19 is supplied to the piezoelectric vibrator 21. Thereby, at the end of the current recording cycle T, the vibrator potential rises from the lowest potential VL to the intermediate potential Vc. As a result, when the discharge waveform element is supplied in the next recording cycle T, the vibrator potential and the start potential of the discharge waveform element are aligned, and the piezoelectric vibrator 21 can be operated smoothly.
[0064]
Further, when the gradation data of the dot indicates recording of any one of small dots, medium dots, and large dots, and the determination data of the next dot indicates non-recording, for example, output data [110] (the dot is a large dot When the next dot is not recorded), the waveform element supplying means supplies the second connecting element P29 to the piezoelectric vibrator 21 in the current recording period T. Thereby, at the end of the current recording cycle T, the vibrator potential drops from the intermediate potential Vc to the lowest potential VL. As a result, the vibrator potential can be kept at the lowest potential VL in the next recording cycle T, and the piezoelectric vibrator 21 can be protected.
[0065]
Further, when the gradation data of the dot indicates recording of a small dot, medium dot, or large dot and the determination data of the next dot indicates recording, for example, output data [011] (the dot is a small dot) In the case where the next dot is recording), the waveform element supply means supplies neither the first connection element P19 nor the second connection element P29 to the piezoelectric vibrator 21 in the current recording period T. Thus, the vibrator potential becomes the intermediate potential Vc at the end of the current recording cycle T. As a result, when the discharge waveform element is supplied in the next recording cycle T, the vibrator potential and the start potential of the discharge waveform element are aligned, and the piezoelectric vibrator 21 can be operated smoothly.
[0066]
Hereinafter, this control will be described in detail. First, the control when the current recording cycle T is non-recording (gradation data [00]) will be described.
[0067]
In this embodiment, the waveform element supply means determines the pulse signals PS1 to PS6 to be selected based on the output data (gradation data, determination data).
[0068]
If the output data is [000], that is, if the next dot determination data is [0] indicating non-recording, the decoder 47 generates selection data [000101]. As a result, the fourth pulse signal PS4 and the sixth pulse signal PS6 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 4A, the switch circuit 50 is turned on in the periods t4 and t6, and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t1 to t3 and t5. Is turned off, and the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0069]
As a result, the piezoelectric vibrator 21 is supplied with the micro-vibration waveform element VP constituted by the first connecting element P19 and the second connecting element P29, and pressure vibrations that do not eject ink droplets are generated in the pressure chamber 33. When excited, the ink is stirred in the vicinity of the nozzle opening 30. Further, after the fine vibration waveform element VP is supplied, the vibrator potential becomes the lowest potential VL, so that the voltage supplied to the piezoelectric vibrator 21 is kept low. Thereby, the burden on the piezoelectric vibrator 21 can be reduced and the life can be extended.
[0070]
In this case, the fine vibration waveform element VP is composed of the first connecting element P19 and the second connecting element P29 for adjusting the vibrator potential, and therefore, the first connecting element P19 and the second connecting element P29 are used. The two connecting elements P29 can be used for various purposes, and a plurality of waveform elements can be efficiently stored even in a limited recording cycle T. Further, since the fourth pulse signal PS4 including the first coupling element P19 is generated between the second ejection waveform element DP2 (P9 to P13) and the third ejection waveform element DP3 (P22 to P26), this point However, a plurality of waveform elements can be efficiently stored in the limited recording period T.
[0071]
When the output data is [001], that is, when the next dot determination data is [1] indicating printing, the decoder 47 generates selection data [000100]. As a result, only the fourth pulse signal PS4 is selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 4B, the switch circuit 50 is turned on in the period t4 and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t1 to t3 and t5 to t6. The supply of the drive signal to the piezoelectric vibrator 21 is stopped in the off state.
[0072]
Thereby, the vibrator potential rises from the lowest potential VL to the intermediate potential Vc by the first connecting element P19 supplied in the period t4, and holds this intermediate potential Vc in the periods t5 to t6. Thereafter, the discharge waveform element is supplied in the next printing cycle T, and the vibrator potential at the start of supply and the start potential of the discharge waveform element are both at the intermediate potential Vc. For this reason, the discharge waveform element can be smoothly supplied to the piezoelectric vibrator 21 without abruptly changing the vibrator potential. For this reason, the vibrator potential can be raised to the intermediate potential Vc even if the recording is not performed in the previous recording cycle T, and the discharge waveform element can be supplied without imposing a burden on the piezoelectric vibrator 21.
[0073]
Next, the control when the current recording cycle T is a small dot (gradation data [01]) will be described.
[0074]
When the output data is [010], that is, when the next dot determination data is [0] indicating non-recording, the decoder 47 generates selection data [010001]. Accordingly, the second pulse signal PS2 and the sixth pulse signal PS6 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 5A, the switch circuit 50 is turned on in the periods t2 and t6, and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t1 and t3 to t5. Is turned off, and the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0075]
As a result, the piezoelectric vibrator 21 is supplied with the second ejection waveform element DP2, and a predetermined amount of ink droplets are ejected once. Further, after the ink droplet is ejected, the second connecting element P29 is supplied, and the vibrator potential becomes the lowest potential VL. For this reason, the vibrator potential is kept at the lowest potential VL in the next recording cycle T. Thereby, the burden on the piezoelectric vibrator 21 can be reduced and the life can be extended.
[0076]
On the other hand, when the output data is [011], that is, when the next dot determination data is [1] indicating printing, the decoder 47 generates selection data [010000]. As a result, the second pulse signal PS2 is selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 5B, the switch circuit 50 is turned on in the period t2, and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is turned off in the periods t1 and t3 to t6. Thus, the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0077]
As a result, the piezoelectric vibrator 21 is supplied with the second ejection waveform element DP2, and a predetermined amount of ink droplets are ejected once. Further, after the ink droplet is ejected, the vibrator potential maintains the intermediate potential Vc. Therefore, in the next printing cycle T, the vibrator potential and the starting end potential of the ejection waveform element are both aligned at the intermediate potential Vc, and the ejection waveform element can be smoothly supplied to the piezoelectric vibrator 21. For this reason, the discharge waveform element can be supplied without imposing a burden on the piezoelectric vibrator 21.
[0078]
Next, the control when the current recording cycle T is a medium dot (gradation data [10]) will be described.
[0079]
When the output data is [100], that is, when the next dot determination data is [0] indicating non-printing, the decoder 47 generates selection data [110001]. As a result, the first pulse signal PS1, the second pulse signal PS2, and the sixth pulse signal PS6 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 6A, the switch circuit 50 is turned on in the periods t1, t2, and t6, and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t3 to t5. Is turned off, and the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0080]
As a result, the first ejection waveform element DP1 (P2 to P6) and the second ejection waveform element DP2 are supplied to the piezoelectric vibrator 21, and a predetermined amount of ink droplets are ejected twice. Further, after the ink droplet is ejected, the second connecting element P29 is supplied, and the vibrator potential becomes the lowest potential VL. For this reason, the burden on the piezoelectric vibrator 21 is reduced, and the life can be extended.
[0081]
On the other hand, when the output data is [101], that is, when the next dot determination data is [1] indicating printing, the decoder 47 generates selection data [110000]. Thus, the first pulse signal PS1 and the second pulse signal PS2 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 6B, the switch circuit 50 is turned on in the periods t1 and t2, and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is turned off in the periods t3 to t6. Thus, the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0082]
As a result, the first ejection waveform element DP1 and the second ejection waveform element DP2 are supplied to the piezoelectric vibrator 21, and a predetermined amount of ink droplets are ejected twice. Further, since the vibrator potential is maintained at the intermediate potential Vc even after the ink droplet is ejected, the ejection waveform element can be smoothly supplied to the piezoelectric vibrator 21 in the next printing cycle T. For this reason, the discharge waveform element can be supplied without imposing a burden on the piezoelectric vibrator 21.
[0083]
Next, the control when the current recording cycle T is a large dot (gradation data [11]) will be described.
[0084]
When the output data is [110], that is, when the next dot determination data is [0] indicating non-recording, the decoder 47 generates selection data [110011]. As a result, the first pulse signal PS1, the second pulse signal PS2, the fifth pulse signal PS5, and the sixth pulse signal PS6 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and applied to the piezoelectric vibrator 21. Supplied. That is, as shown in FIG. 7A, the switch circuit 50 is turned on in the periods t1, t2, t5, and t6 and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t3 and t4. Is turned off, and the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0085]
As a result, the first ejection waveform element DP1, the second ejection waveform element DP2, and the third ejection waveform element DP3 are supplied to the piezoelectric vibrator 21, and a predetermined amount of ink droplets are ejected three times. Further, since the vibrator potential becomes the lowest potential VL after the ink droplet is ejected, the burden on the piezoelectric vibrator 21 is reduced, and the life can be extended.
In this case, since the second connecting element P29 is generated after the third ejection waveform element DP3 which is the last ejection waveform element, the recording cycle T immediately before the non-recording is large dot recording. In other words, even when recording is performed using the third ejection waveform element DP3, this recording can be performed without any trouble.
[0086]
On the other hand, when the output data is [111], that is, when the next dot determination data is [1] indicating printing, the decoder 47 generates selection data [110010]. Thus, the first pulse signal PS1, the second pulse signal PS2, and the fifth pulse signal PS5 are selected from the first pulse signal PS1 to the sixth pulse signal PS6 and supplied to the piezoelectric vibrator 21. That is, as shown in FIG. 7B, the switch circuit 50 is turned on in the periods t1, t2, and t5 and the drive signal is supplied to the piezoelectric vibrator 21, and the switch circuit 50 is supplied in the periods t3, t4, and t6. Is turned off, and the supply of the drive signal to the piezoelectric vibrator 21 is stopped.
[0087]
As a result, the first ejection waveform element DP1, the second ejection waveform element DP2, and the third ejection waveform element DP3 are supplied to the piezoelectric vibrator 21, and a predetermined amount of ink droplets are ejected three times. Further, since the vibrator potential is maintained at the intermediate potential Vc even after the ink droplet is ejected, the ejection waveform element can be smoothly supplied to the piezoelectric vibrator 21 in the next printing cycle T. For this reason, the discharge waveform element can be supplied without imposing a burden on the piezoelectric vibrator 21.
[0088]
In this embodiment, when non-recording continues in each recording cycle T, for example, as shown in FIG. 8, the micro-vibration waveform element VP is supplied in each recording cycle T. The vibrator potential is kept at the lowest potential VL during the non-supply period of the fine vibration waveform element VP. For this reason, the burden on the piezoelectric vibrator 21 can be reduced, and the life of the piezoelectric vibrator 21 can be extended.
[0089]
In the case of shifting from dot recording to non-recording, for example, as shown in FIG. 9, the second connecting element P29 is supplied to the piezoelectric vibrator 21 immediately before shifting to the non-recording recording cycle T, and vibration is generated. The child potential falls to the lowest potential VL. Accordingly, the vibrator potential is maintained at the lowest potential VL in the non-recording recording cycle T, and the life of the piezoelectric vibrator 21 can be extended.
[0090]
On the contrary, when shifting from non-recording of dots to recording, for example, as shown in FIG. 10, the first connecting element P19 is supplied to the piezoelectric vibrator 21 in a cycle immediately before shifting to the non-recording recording cycle T. Then, the vibrator potential rises to the intermediate potential Vc. Therefore, the vibrator potential is maintained at the intermediate potential Vc until the ejection waveform element (DP2) is supplied in the next recording cycle T, and the ejection waveform element can be smoothly supplied.
[0091]
Further, when dots are recorded continuously in the previous recording cycle T and the current recording cycle T, for example, as shown in FIG. The vibrator potential at the end is set to the intermediate potential Vc. Thus, the vibrator potential is constant at the intermediate potential Vc during the period from the end of the supply of the discharge waveform element (DP3) in the current recording cycle T to the start of the supply of the discharge waveform element (DP1) in the next recording cycle T. Therefore, there is no sudden rise or fall in a short time. For this reason, the burden on the piezoelectric vibrator 21 can be reduced and protected. Further, since the vibrator potential is constant, the volume of the pressure chamber 33 is not changed, and the ink pressure can be stabilized. As a result, it is possible to prevent ink droplets from being bent.
[0092]
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.
[0093]
First, in the above embodiment, the first connection element P19 that increases the potential from the lowest potential VL (base potential) to the intermediate potential Vc (drive potential) and the second connection that decreases the potential from the intermediate potential Vc to the lowest potential VL. Although the element P29 is included in the drive signal and the first connecting element P19 and the second connecting element P29 are supplied to the piezoelectric vibrator 21 to adjust the vibrator potential, the invention is not limited to this configuration. Absent.
[0094]
For example, the vibrator potential adjusting means is constituted by a resistance element and an adjustment switch means for connecting the piezoelectric vibrator to a base potential supply source via the resistance element, and supplying the drive potential via the resistance element. The vibrator potential may be adjusted with Hereinafter, a modified example configured as described above will be described.
[0095]
FIGS. 12A and 12B are diagrams for explaining this modified example. FIG. 12A is a diagram for explaining the circuit configuration of the main part, and FIGS.
In this modification, an adjustment switch 61 (corresponding to the adjustment switch means) is provided between the switch circuit 50 and the piezoelectric vibrator 21, and the piezoelectric vibrator is connected via the adjustment switch 61 and the resistance elements 62 and 63. 21 is configured to be selectively connectable to a drive signal supply line (corresponding to a drive potential supply source) and a ground line (corresponding to a base potential supply source). Accordingly, with respect to the drive signal generated by the drive signal generation circuit 9 (see FIG. 3), the third pulse signal PS3, the fourth pulse signal PS4, and the sixth pulse signal PS6 are not generated in the periods t3, t4, and t6. A constant intermediate potential Vc is generated. Note that the pulse signals PS1, PS2, and PS5 are generated in the periods t1, t2, and t5.
[0096]
The control of this modification is basically the same as that of the above embodiment, but differs in the following points. That is, in the period t4, instead of selecting the fourth pulse signal PS4, the adjustment switch 61 is connected to the resistance element 62 side (drive potential supply side) with the switch circuit 50 turned off. In the period t6, instead of selecting the sixth pulse signal PS6, the adjustment switch 61 is connected to the resistance element 63 side (base potential supply source side) with the switch circuit 50 turned off.
[0097]
In this control, when a drive potential supply source is connected to the piezoelectric vibrator 21 over a period t4, the piezoelectric vibrator 21 is charged via the resistance element 62. Thereby, as shown in FIG. 12B, the vibrator potential rises relatively slowly with time. As a result, similarly to the case where the fourth pulse signal PS4 is supplied, the vibrator potential at the end of the period t4 can be adjusted to the intermediate potential Vc.
In addition, when the base potential supply source is connected to the piezoelectric vibrator 21 over the period t <b> 6, the piezoelectric vibrator 21 is discharged via the resistance element 63. Thereby, as shown in FIG.12 (c), vibrator | oscillator electric potential falls comparatively gently with progress of time. As a result, similarly to the case where the sixth pulse signal PS6 is supplied, the vibrator potential can be adjusted to the lowest potential VL before the next recording period T arrives.
In these cases, the degree (inclination) of the rise or fall of the vibrator potential can be adjusted by changing the resistance values of the resistance elements 62 and 63. For this reason, adjustment is also easy.
The on / off control of the adjustment switch 61 can be performed by the control unit 6, but is not limited thereto. For example, it may be controlled by a switch with a timer function.
[0098]
In this configuration, since it is sufficient to generate the intermediate potential Vc from the drive signal generation circuit 9 in the periods t3, t4, and t6, the control unit 6 serving as the waveform generation control means drives over these periods. There is no need to control the signal generation circuit 9. Further, the time required for the on / off control of the adjustment switch 61 is very short between the on time and the off time.
For this reason, the control unit 6 can perform other processing, for example, control of the carriage mechanism 11 and the paper feed mechanism 12 in each of the periods t3, t4, and t6. Therefore, the limited time can be used efficiently.
[0099]
In the above embodiment, the plurality of ejection drive pulses all have the same waveform shape, but the present invention is not limited to this, and may have different waveform shapes. Further, the drive potential is not limited to the intermediate potential Vc and can be set to any potential higher than the base potential. Similarly, the base potential is not limited to the ground potential as long as it is a low potential suitable for protecting the piezoelectric vibrator 21.
[0100]
【The invention's effect】
As described above, the present invention has the following effects.
That is, the vibrator potential adjusting means adjusts the vibrator potential to the base potential when the next recording cycle is non-recording based on the gradation data and the determination data, and drives the vibrator potential when the next recording cycle is recording. Since the potential is adjusted, when the next recording cycle is non-recording, the vibrator potential is maintained at the base potential in the next recording cycle, and the piezoelectric vibrator is protected. Further, when recording is performed in the next recording cycle, the transducer potential is adjusted to the drive potential within the current recording cycle, so that the transducer potential and the start potential of the ejection waveform element are aligned. For this reason, the ejection drive pulse can be smoothly supplied to the piezoelectric vibrator, the burden on the piezoelectric vibrator is reduced, and the piezoelectric vibrator can be protected.
[0101]
Further, the vibrator potential adjusting means is constituted by the waveform element supply means, and the waveform element is selectively supplied to the piezoelectric vibrator according to the determination data of the next recording period so as to adjust the terminal potential in the current recording period. In this case, the device configuration can be simplified without the need for a special component member.
[0102]
Further, when at least one ejection waveform element is generated between the first connection element and the second connection element, the waveform element can be efficiently accommodated in a limited recording cycle.
[0103]
In addition, when the second connecting element is generated after the last ejection waveform element in the recording cycle, all ejection waveform elements can be used in the current recording cycle, which may hinder gradation recording in the current recording cycle. The vibrator potential can be adjusted without coming.
[0104]
Further, when the first coupling element is generated between the adjacent ejection waveform elements, the waveform elements can be efficiently contained within a limited recording cycle.
[0105]
In addition, when the connection element is generated between the discharge waveform element and the first coupling element, the generation interval between the adjacent discharge waveform elements can be reduced, and the waveform can be efficiently used within a limited recording cycle. Can contain elements.
[0106]
Further, when the ink in the pressure chamber is agitated by selecting the first connecting element and the second connecting element, these connecting elements can be used for various purposes, and within a limited recording cycle. Can efficiently accommodate waveform elements.
[0107]
In the case where the vibrator potential adjusting means is constituted by a resistance element and an adjustment switch means for selectively connecting the piezoelectric vibrator to a drive potential supply source or a base potential supply source via the resistance element. Since the vibrator potential can be adjusted by the operation of the adjustment switch means, it is sufficient for the drive signal generating means to generate a signal having a constant potential during that period, and control is not required. For this reason, the efficiency of control can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an ink jet recording apparatus of the present invention.
FIG. 2 is a diagram illustrating a mechanical structure of a recording head.
FIG. 3 is a diagram illustrating a drive signal.
FIGS. 4A and 4B are diagrams for explaining a waveform element selection pattern, in which FIG. 4A shows a case where both the current recording period and the next recording period are non-recording, and FIG. The case where the recording cycle is recording is shown.
FIGS. 5A and 5B are diagrams for explaining a waveform element selection pattern, in which FIG. 5A shows a case where the current recording cycle is a recording of small dots and the next recording cycle is non-recording, and FIG. A case where the recording is a small dot and the next recording cycle is recording is shown.
6A and 6B are diagrams for explaining a waveform element selection pattern, in which FIG. 6A shows a case where the current recording cycle is medium dot recording and the next recording cycle is non-recording, and FIG. This is a case where medium dot recording is performed and the next recording cycle is recording.
FIGS. 7A and 7B are diagrams for explaining a waveform element selection pattern, in which FIG. 7A shows a case where the current recording cycle is large dot recording and the next recording cycle is non-recording, and FIG. This is a case where large dots are recorded and the next recording cycle is recording.
FIG. 8 is a diagram for explaining a selection pattern of waveform elements when non-recording continues.
FIG. 9 is a diagram illustrating a waveform element selection pattern when switching from small dot recording to non-recording.
FIG. 10 is a diagram for explaining a waveform element selection pattern when switching from non-recording to small dot recording;
FIG. 11 is a diagram illustrating a selection pattern of waveform elements when large dots are continuously recorded.
FIGS. 12A and 12B are diagrams illustrating a modification of the present invention, where FIG. 12A is a block diagram illustrating a configuration of a main part, and FIGS. 12B and C are diagrams illustrating changes in vibrator potential.
[Explanation of symbols]
1 Printer controller
2 Print engine
3 External I / F
4 RAM
5 ROM
6 Control unit
7 Oscillator circuit
8 Recording head
9 Drive signal generation circuit
10 Internal I / F
11 Carriage mechanism
12 Paper feed mechanism
21 Piezoelectric vibrator
22 Channel unit
23 Actuator unit
24 Ink supply port
25 1st nozzle communication hole
26 Supply port forming substrate
27 Common ink chamber
28 Second nozzle communication hole
29 Ink chamber forming substrate
30 Nozzle opening
31 Nozzle plate
32 First lid member
33 Pressure chamber
34 Pressure chamber forming substrate
35 Supply side communication hole
36 Second lid member
37 Common electrode
38 Piezoelectric layer
39 Drive electrode
41 First shift register
42 Second shift register
43 Third shift register
44 First latch circuit
45 Second latch circuit
46 Third latch circuit
47 Decoder
48 Control logic
49 Level Shifter
50 switch circuit
61 Adjustment switch
62,63 resistance element

Claims (10)

A piezoelectric vibrator capable of causing pressure fluctuations in the pressure chamber, a recording head having a nozzle opening communicating with the pressure chamber, and a drive signal generating means for repeatedly generating a series of drive signals including a plurality of waveform elements at each recording period; In an inkjet recording apparatus that includes waveform element supply means for supplying a waveform element selected according to gradation data to a piezoelectric vibrator, and capable of multi-gradation recording,
A recording state determination unit that determines the presence or absence of recording based on gradation data in the next recording cycle and obtains determination data, and a transducer potential adjustment unit that adjusts the transducer potential in the current recording cycle,
The waveform element generated by the drive signal generating means includes a plurality of ejection waveform elements that are waveform elements for ejecting ink droplets and whose start / end potential is set to a drive potential higher than the base potential,
The vibrator potential adjusting means adjusts the vibrator potential to the drive potential at the end of the current recording cycle when the next recording cycle judgment data indicates recording, and when the non-recording indicates the transducer potential at the end of the current recording cycle. Is adjusted to a base potential. The waveform element generated by the drive signal generating means includes a first connection element that increases the potential from the base potential to the drive potential, and a second connection element that decreases the potential from the drive potential to the base potential,
The vibrator potential adjusting means includes a waveform element supply means, and the vibrator potential is adjusted by selectively supplying a waveform element to the piezoelectric vibrator in accordance with determination data of a next recording cycle. 2. An ink jet recording apparatus according to 1. 3. The ink jet recording apparatus according to claim 2, wherein the drive signal generating unit generates at least one ejection waveform element between the first connection element and the second connection element. 4. The ink jet recording apparatus according to claim 2, wherein the drive signal generating unit generates the second connecting element after the last ejection waveform element in a recording cycle. 5. The ink jet recording apparatus according to claim 2, wherein the drive signal generating unit generates the first connecting element between adjacent ejection waveform elements. 6. The drive signal generating means changes the potential between the terminal potential of the discharge waveform element and the start potential of the first connection element, but does not supply the piezoelectric vibrator to the connection element. The ink jet recording apparatus according to claim 5, wherein the ink jet recording apparatus occurs during The waveform element selecting means selects the first connecting element and the second connecting element when both the current recording period and the next recording period indicate non-recording, and stirs the ink in the pressure chamber. Item 7. The ink jet recording apparatus according to any one of Items 2 to 6. The vibrator potential adjusting means includes a resistance element and an adjustment switch means for selectively connecting the piezoelectric vibrator to a drive potential supply source or a base potential supply source via the resistance element. The ink jet recording apparatus according to claim 1. 9. The ink jet recording apparatus according to claim 1, wherein a plurality of ejection waveform elements generated by the drive signal generating means have the same waveform shape. A drive signal including a plurality of waveform elements is repeatedly generated every recording period, a waveform element is selected according to gradation data, and the selected waveform element is supplied to the piezoelectric vibrator of the recording head, thereby generating a multi-gradation In a driving method of an ink jet recording apparatus that performs recording,
The waveform element is a waveform element for discharging ink droplets, and includes a plurality of discharge waveform elements in which a start / end potential is set to a drive potential higher than a base potential,
Based on the gradation data in the current recording cycle and the judgment data in the next recording cycle, the vibrator potential at the end of the current recording cycle is adjusted to the base potential when the next recording cycle is not recorded, and the next recording cycle A method of driving an ink jet recording apparatus, characterized in that in the case of recording, the driving potential is adjusted.

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