JP2009154493A - Method and device for driving inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve printing quality by correcting variations in ink drop measure. <P>SOLUTION: A driving voltage generation part 46 can vary the driving voltage of a driving pulse signal. A drop number selection part 45 determines for each nozzle the number of ink drop jets according to data per pixel for the nozzle. A switch selection part 44 selects for each nozzle a driving voltage within the variable range. A driving pulse signal generation part 47 generates driving pulse signals of the selected voltage by the determined number of jets, and applies them to an actuator ACT for an ink chamber with the nozzle formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving method and a driving apparatus for an inkjet head used in a multi-drop type inkjet printer.

  In general, an inkjet head is provided corresponding to each ink chamber, a plurality of ink chambers each filled with ink, a plurality of nozzles formed in communication with each ink chamber, and the ink from the nozzles. And a plurality of drive elements for discharging the liquid.

  In the case of a piezo ink jet printer, the drive element is an actuator that causes a volume change in the ink chamber, and in the case of a thermal ink jet printer, the drive element is a heating element that generates bubbles for ejection driving in the ink chamber.

  In the ink jet head having such a configuration, when a driving pulse signal is applied to a certain driving element, the driving element is activated, and ink droplets are ejected from a nozzle communicating with the ink chamber provided with the driving element. .

  Ink jet printers include models that perform printing and recording by a driving method called a multi-drop method. In such an ink jet printer, one pixel is formed by discharging a plurality of ink droplets from one nozzle. Accordingly, the ink droplet amount per pixel can be adjusted by adjusting the number of pulses of the drive pulse signal. That is, gradation printing is possible.

Conventionally, it is already known that an ink jet head used in such an ink jet printer suppresses heat generation of the ink jet head and reduces variations in ejection speed due to a temperature difference between the ink chambers (for example, Patent Documents). 1).
JP 2002-361866 A

  However, the dimensions of the plurality of ink chambers and nozzle diameters constituting one ink jet head are not necessarily uniform. Also, the performance of each heating element varies. For this reason, even when drive pulse signals having the same voltage are applied to different heating elements, the volume of ink droplets ejected from the nozzles is not necessarily constant. For this reason, there is a possibility that desired gradation printing cannot be performed.

  The present invention has been made based on such circumstances, and an object of the present invention is to provide an ink jet head driving method and a driving apparatus capable of correcting variations in ink droplet amount and improving printing quality. It is something to try.

  The present invention provides a plurality of ink chambers for storing ink therein, nozzles formed to communicate with the respective ink chambers, and a plurality of ink chambers that are provided corresponding to the respective ink chambers and that eject the ink from the nozzles. The drive voltage of the drive pulse signal can be varied with respect to the ink jet head including the drive element. Then, for each nozzle, the number of ink droplets to be ejected is determined based on the data per pixel for that nozzle, the driving voltage within the variable range is selected, and the driving pulse signal of this selected voltage is determined. The generated number of ejections is generated and applied to the drive element of the ink chamber in which the nozzle is formed.

  According to the present invention in which such a measure is taken, it is possible to correct variations in the amount of ink droplets and improve the printing quality.

The best mode for carrying out the present invention will be described below with reference to the drawings.
This embodiment is a case where the present invention is applied to a piezo-type multi-drop type ink jet printer.

(First embodiment)
First, a first embodiment corresponding to the invention according to claims 1 and 3 of the present application will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a schematic configuration of the ink jet printer 1. The inkjet printer 1 includes an inkjet head 11, an inkjet head driving device 12 that drives the inkjet head 11, and a printer controller 13 that controls each part of the printer including the inkjet head driving device 12.

  The printer controller 13 is connected to a host computer 2 as print data generating means. When print data is received from the host computer 2, the printer controller 13 controls the operation of each unit including the inkjet head 11 and its driving device 12 to realize print recording on a recording medium.

Next, the principal part structure of the inkjet head 11 is demonstrated using FIG.2 and FIG.3. 3 is a cross-sectional view taken along the line AA in FIG.
The ink-jet head 11 is formed by partitioning a plurality of ink chambers 31 for storing ink by partition walls 32, and nozzles 33 for ejecting ink droplets are provided in the respective ink chambers 31 in communication with the ink chambers 31. ing. A plurality of nozzles 33 provided in each ink chamber 31 are arranged in one direction. In the ink jet printer 1, the recording medium is relatively moved in a direction orthogonal to the arrangement direction of the nozzle rows.

  The bottom surface of each ink chamber 31 is formed by a vibration plate 34, and a plurality of piezoelectric members 35 are fixed to the lower surface side of the vibration plate 34 corresponding to each ink chamber 31. The diaphragm 34 and the piezoelectric member 35 constitute an actuator ACT as a driving element, and the piezoelectric member 35 is electrically connected to the output terminal 3 of the inkjet head driving device 12.

  The ink jet head 11 is also formed with a common ink chamber 36 communicating with the ink chambers 31. Ink is injected into the common ink chamber 36 from an ink supply means (not shown) via an ink supply port 37. Thus, the common ink chamber 36, each ink chamber 31, and the nozzle 33 are filled with ink.

Next, the data structure per pixel of the ejection data given from the printer controller 13 to the inkjet head drive device 12 will be described with reference to FIG.
Before that, when the printer controller 13 receives print data from the host computer 2, the print controller 13 develops the print data into pixel data on the print buffer. Then, the developed pixel data is output to the inkjet head driving device 12 as ejection data for each line.

  In the inkjet head driving device 12, each actuator ACT of the inkjet head 11 is selectively driven according to the ejection data input from the printer controller 13, and a required number of ink droplets are ejected from the nozzle 33 corresponding to the actuator ACT. Thereby, one line of pixels is formed on the recording medium. By repeating this pixel forming operation for each line, an image of print data is recorded on the recording medium. One line corresponds to the nozzle row of the inkjet head 11.

  In the present embodiment, as shown in FIG. 4, pixel data per pixel generated by the printer controller 13 is data consisting of 4 bits of D4, D3, D2, and D1 from the higher order. Of the 4-bit data, the lower 2 bits [D2, D1] are the drop number selection data, and the upper 2 bits [D4, D3] are the switch selection data. The drop number selection data is the number of drops required to form one pixel of the pixel data, that is, the number of ink droplets. The switch selection data is data for selecting a driving voltage necessary for forming one pixel of the pixel data from a variable range.

  As described above, in this embodiment, the drop number selection data and the switch selection data are both 2-bit data. That is, any one of four patterns [00], [01], [10], and [11] is used. This is because in this embodiment, the number of gradations of one pixel is set to 4 gradations of 0 to 3. This is because the drive voltage required to form one pixel is selected from four types of V1 to V4 (where V1> V2> V3> V4).

  In other words, when the number of gradations of one pixel is 5 gradations or more, the drop number selection data may be data of 3 bits or more. Similarly, when there are five or more selectable drive voltages, the switch selection data may be data of 3 bits or more.

  The principal part structure of the inkjet head drive device 12 is demonstrated using FIG.5 and FIG.6. FIG. 6 is a diagram illustrating an example of a circuit formed in the drive pulse signal generation unit 47 corresponding to each of the plurality of actuators ACT constituting the inkjet head 11.

  The inkjet head driving device 12 includes a shift register 41, a latch circuit 42, a reference pulse generation circuit 43, a switch selection unit 44, a drop number selection unit 45, a drive voltage generation unit 46, and a drive pulse signal generation unit 47.

  The shift register 41 converts the ejection data for one line supplied as serial data from the printer controller 13 into parallel data for each pixel. The latch circuit 42 temporarily holds the parallel data for each pixel converted by the shift register 41. The parallel data held in the latch circuit 42 is separated into upper 2-bit switch selection data and lower 2-bit drop number selection data for each ejection data of one pixel. The parallel data of the switch selection data is input to the switch selection unit 44, and the parallel data of the drop number selection data is input to the drop number selection unit 45.

  The reference pulse generation circuit 43 repeatedly generates a predetermined number M of reference pulse signals (where 1 <M, where M is the number of ink droplets of the maximum gradation: 3 in the present embodiment). The reference pulse signal is input to the switch selection unit 44 and the drop number selection unit 45.

  The switch selection unit 44 generates first to fourth switch selection signals P1 to P4 for each pixel according to switch selection data based on the reference pulse signal (drive voltage selection unit). Specifically, when the switch selection data is [00], the first switch selection signal P1 is generated. When the switch selection data is [01], the second switch selection signal P2 is generated. 10], the third switch selection signal P3 is generated. If [11], the fourth switch selection signal P4 is generated. The first to fourth switch selection signals P1 to P4 for each pixel are output to the drive pulse signal generation unit 47, respectively.

  The drop number selection unit 45 generates a drop number selection signal N for each pixel in accordance with the pulse number selection data based on the reference pulse signal (discharge number determination means). Specifically, when the pulse number selection data is [00], a selection signal N with a drop number “0” is generated, and when it is [01], a selection signal N with a drop number “1” is generated. When [10], the selection signal N with the drop number “2” is generated, and when [11], the selection signal N with the drop number “3” is generated. Each drop number selection signal N for each pixel is output to the drive pulse signal generation unit 47.

  The drive voltage generator 46 generates four different types of drive voltages V1, V2, V3, and V4 (where V1> V2> V3> V4) (drive voltage varying means). The drive voltages V1, V2, V3, and V4 are applied to the drive pulse signal generation unit 47.

  Based on the first to fourth switch selection signals P1 to P4 and the drop number selection signal N, the drive pulse signal generator 47 generates a drive pulse signal of voltage V1, V2, V3, or V4 for each pixel. Is generated (driving signal generation means). Each drive pulse signal for each pixel is applied to each actuator ACT of the inkjet head 11.

  In the drive pulse signal generation unit 47, the drive pulse signal generation circuits 50 having the circuit configuration shown in FIG. 6 are formed corresponding to each actuator ACT by the number of the actuators ACT. As shown in the drawing, the drive pulse signal generation circuit 50 includes five switching elements SW1 to SW5 using MOSFETs. Among the switching elements, the first to fourth switching elements SW1 to SW4 are formed by P-channel MOSFETs. The fifth switching element SW5 is formed of an N channel MOSFET.

  The first to fourth switch selection signals P1 to P4 for one pixel are input to the gate terminals of the first to fourth switching elements SW1 to SW4, respectively. A drop number selection signal N for one pixel is input to the gate terminal of the fifth switching element SW5. The drive voltages V1, V2, V3, and V4 are applied to the source terminals of the first to fourth switching elements SW1 to SW4, respectively. The drain terminals of the first to fourth switching elements SW1 to SW4 and the source terminal of the fifth switching element SW5 are connected to the output terminal 3 to the corresponding actuator ACT. The drain terminal of the fifth switching element SW5 is grounded.

  In the drive pulse signal generation circuit 50 having such a configuration, when the first switch selection signal P1 is input, the first switching element SW1 is turned on. As a result, the potential of the output terminal 3 becomes the drive voltage V1. Similarly, when the second switch selection signal P2 is input, the second switching element SW2 is turned on. Therefore, when the potential of the output terminal 3 takes the drive voltage V2 and the third switch selection signal P3 is input. Since the third switching element SW3 is turned on, the potential of the output terminal 3 becomes the drive voltage V3, and when the fourth switch selection signal P4 is inputted, the fourth switching element SW4 is turned on, so that the output terminal 3 Becomes V4.

  On the other hand, when the drop number selection signal N is input, the fifth switching element SW5 is turned ON. As a result, the output terminal 3 is grounded. Thus, each time the drop number selection signal N is input, the drive voltage Vi corresponding to the switching element SWi in the ON state (where 1 ≦ i ≦ 4) among the first to fourth switching elements SW1 to SW4. A pulse signal is applied to the actuator ACT.

  Ink droplets are ejected from nozzles 33 provided in communication with the ink chambers 31 due to volume changes in the ink chambers 31 caused by applying pulse signals of the drive voltages V1 to V4 to the actuators ACT. The dots formed by this one ink droplet are schematically shown in FIG. In the figure, (a) is the dot G1 when the pulse signal of the drive voltage V1 is applied, (b) is the dot G2 when the pulse signal of the drive voltage V2 is applied, and (c) is The dot G3 is when the pulse signal of the driving voltage V3 is applied, and (d) is the dot G4 when the pulse signal of the driving voltage V4 is applied. As shown in the figure, the higher the drive voltages V1 to V4, the larger the volume of the ink droplets ejected from the nozzle 33, and the larger the diameter dots are formed. That is, the dots have a relationship of G1> G2> G3> G4.

  Specific operations of the switch selection unit 44 and the drop number selection unit 45 will be further described with reference to the timing diagrams of FIGS. FIG. 8 is a timing diagram of the switch selection unit 44, and FIG. 9 is a timing diagram of the drop number selection unit 45. This example is when the ejection data of one pixel is [0110] and [1111].

  As shown in FIG. 8, when the ejection data is [0110], the switch selection data consisting of the upper 2 bits is [01]. In this case, the second switch selection signal P2 is generated. That is, the second switch selection signal P2 is generated in synchronization with the reference pulse signal input from the reference pulse generating circuit 43. At this time, the other switch selection signals P1, P3, and P4 are all at the ground level.

  If the ejection data is [1111], the switch selection data consisting of the upper 2 bits is [11]. In this case, the fourth switch selection signal P4 is generated. That is, the fourth switch selection signal P4 is generated in synchronization with the reference pulse signal input from the reference pulse generation circuit 43. At this time, the other switch selection signals P1, P2, and P3 are all at the ground level.

  As shown in FIG. 9, when the ejection data is [0110], the drop number selection data consisting of the lower 2 bits is [10]. In this case, a selection signal N having a drop number “2” is generated. That is, a drop number selection signal N for generating two pulses is generated in synchronization with the falling edge of the reference pulse signal input from the reference pulse generation circuit 43.

  If the ejection data is [1111], the drop number selection data consisting of the lower 2 bits is [11]. In this case, a selection signal N having a drop number “3” is generated. That is, a drop number selection signal N for generating three pulses is generated in synchronization with the falling edge of the reference pulse signal input from the reference pulse generating circuit 43.

  As described above, when the ejection data of one pixel is [0110], the switch selection unit 44 generates the second switch selection signal P2 in synchronization with the reference pulse signal, and the drive pulse signal generation unit 47. Is output. Further, a drop number selection signal N having a drop number “2” is generated from the drop number selection unit 45 in synchronization with the fall of the reference pulse signal, and is output to the drive pulse signal generation unit 47.

  As a result, in the drive pulse signal generation unit 47, as shown in the period T1 in FIG. 10, two pulses of the drive pulse signal with the drive voltage V2 are generated. This drive pulse signal is applied to the actuator ACT via the output terminal 3. Then, the actuator ACT is activated, and the volume of the ink chamber 31 is changed. Specifically, the volume of the ink chamber 31 expands in the section t1 of the drive pulse signal, and the volume of the ink chamber 31 contracts in the subsequent section t2. Due to such volume change, ink droplets are ejected from the nozzles communicating with the ink chamber 31. That is, in this case, one pixel is formed by ejecting two ink droplets.

  When the ejection data of one pixel is [1111], the switch selection unit 44 generates the fourth switch selection signal P4 and outputs it to the drive pulse signal generation unit 47. Further, a drop number selection signal N having a drop number “3” is generated from the drop number selection unit 45 and is output to the drive pulse signal generation unit 47.

  Thereby, in the drive pulse signal generation unit 47, as shown in the period T2 in FIG. 10, three pulses of the drive pulse signal whose drive voltage is V3 are generated. This drive pulse signal is applied to the actuator ACT via the output terminal 3. As a result, the ink chamber 31 operates in the same manner as described above, and three ink droplets are ejected from the nozzle to form one pixel.

  Now, when the pulse signal of the drive voltage V1 is applied to the actuator ACT, the volume of the ink droplet ejected from the nozzle 33 is 7 [pL], and when the pulse signal of the drive voltage V2 is applied to the actuator ACT. The volume of the ink droplet ejected from the nozzle 33 is 6 [pL], and the volume of the ink droplet ejected from the nozzle 33 when the pulse signal of the drive voltage V3 is applied to the actuator ACT is 5 [pL]. Assume that the volume of the ink droplet ejected from the nozzle 33 when the pulse signal of the drive voltage V4 is applied to the actuator ACT is 4 [pL].

  In the present embodiment, ink droplets are repeatedly ejected by the number of drops of the drop number selection signal N to form one pixel. Therefore, for a pixel to which the voltage of the drive pulse signal is V1, that is, the first switch selection signal P1 is input, one pixel is formed with an ink amount of 7 [pL] when the number of drops is “1”. When the number of drops is “2”, one pixel is formed with an ink amount of 14 [pL], and when the number of drops is “3”, one pixel is formed with an ink amount of 21 [pL]. .

  Similarly, for a pixel to which the voltage of the drive pulse signal is V2, that is, the second switch selection signal P2 is input, when the number of drops is “1”, one pixel is obtained with an ink amount of 6 [pL]. When the number of drops is “2”, one pixel is formed with an ink amount of 12 [pL], and when the number of drops is “3”, one pixel is formed with an ink amount of 18 [pL]. The

  Further, for a pixel to which the voltage of the drive pulse signal is V3, that is, the third switch selection signal P3 is input, one pixel is formed with an ink amount of 5 [pL] when the number of drops is “1”. When the number of drops is “2”, one pixel is formed with an ink amount of 10 [pL], and when the number of drops is “3”, one pixel is formed with an ink amount of 15 [pL]. .

  Further, for a pixel to which the voltage of the drive pulse signal is V4, that is, the fourth switch selection signal P4 is input, one pixel is formed with an ink amount of 4 [pL] when the number of drops is “1”. When the number of drops is “2”, one pixel is formed with an ink amount of 8 [pL], and when the number of drops is “3”, one pixel is formed with an ink amount of 12 [pL]. .

  That is, in the present embodiment, one pixel is converted into 4, 5, 6, 7, 8, 10, 12, 14, and the combination of the drop number selection data and the switch selection data constituting the pixel data per pixel. It can be formed with an ink amount of 15, 18 or 21 [pL].

  As described above, according to the present embodiment, it is possible to finely set the ink droplet amount per pixel. Therefore, for example, even if there is a variation in the amount of ink droplets between nozzles due to variations in the dimensions of ink chambers or nozzle diameters, or variations in the performance of each actuator, the variations can be easily corrected.

  Further, even if the same nozzle is used, there is a case where a crosstalk occurs due to the influence of the volume change of the ink chambers adjacent to each other, and a desired ink droplet amount cannot be obtained. Therefore, it can be easily corrected. Thus, the print quality can be improved.

(Second Embodiment)
Next, a second embodiment corresponding to the invention according to claims 2 and 4 of the present application will be described with reference to FIGS.
Also in the second embodiment, the schematic configuration of the inkjet printer 1, the main configuration of the inkjet head 11, and the data configuration per pixel of the ejection data given from the printer controller 13 to the inkjet head driving device 12 are also the first. This is the same as the embodiment. Therefore, the description thereof is omitted with reference to FIGS.

  FIG. 11 is a block diagram showing a main configuration of the inkjet head driving device 12 according to the second embodiment. In this figure, the same reference numerals are assigned to the same parts as those of the inkjet head driving device 12 of the first embodiment shown in FIG. That is, in the second embodiment, the drive voltage generated by the drive voltage generator 461 is one type (voltage V). Therefore, in the drive pulse signal generation unit 471, the drive pulse signal generation circuit 501 having the circuit configuration shown in FIG. 12 is formed corresponding to each actuator ACT. That is, a common drive voltage V is applied to each source terminal of the first to fourth switching elements SW1 to SW4. The other aspects are the same as in the first embodiment.

  However, in the second embodiment, the on-resistances Ron of the first to fourth switching elements SW1 to SW4 formed by P-channel MOSFETs are different from each other. Specifically, the on-resistance of the first switching element SW1 is Ron1, the on-resistance of the second switching element SW2 is Ron2, the on-resistance of the third switching element SW3 is Ron3, and the on-resistance of the fourth switching element SW4. Is Ron4, the on-resistance Ron of each of the switching elements SW1 to SW4 is designed so as to have a relationship of Ron1 <Ron2 <Ron3 <Ron4.

  In the MOSFET, the larger the on-resistance Ron, the slower the rise time and fall time of the pulse waveform. Therefore, in the second embodiment having the relationship of Ron1 <Ron2 <Ron3 <Ron4, the first switch selection signal P1 is input to the on-resistance Ron of each switching element SW1 to SW4, and the first switching element SW1. Is the earliest rise time and fall time of the drive pulse signal, and is the latest when the fourth switch selection signal P4 is input and the fourth switching element SW4 is turned on. The second switch selection signal P2 is input to turn on the second switching element SW2, and the third switch selection signal P3 is input to turn on the third switching element SW3. When the third switching element SW3 is turned on, the rise time and the fall time of the drive pulse signal are later than when the second switching element SW1 is turned on.

  On the other hand, when the drop number selection signal N is input to the base of the fifth switching element SW5, the fifth switching element SW5 is turned ON. Thus, each time the drop number selection signal N is input, the drive voltage Vi corresponding to the switching element SWi in the ON state (where 1 ≦ i ≦ 4) among the first to fourth switching elements SW1 to SW4. The pulse signal is applied to the actuator ACT through a rise time determined by the on-resistance Roni of the switching element SWi.

  As a result, when the drive pulse signal is applied to the actuator ACT, an ink droplet is ejected from the corresponding nozzle 33. The dots formed by this one ink droplet are schematically shown in FIG. In the figure, (a) is a dot G1 when a drive pulse signal is applied when the first switching element SW1 is turned on, and (b) is a drive pulse when the second switching element SW1 is turned on. A dot G2 when a signal is applied, (c) is a dot G3 when a drive pulse signal is applied when the third switching element SW1 is turned ON, and (d) is a fourth switching element. This is the dot G4 when the drive pulse signal when SW1 is turned on is applied. As shown in the figure, the earlier the rise time and fall time of the drive pulse signal, the larger the volume of ink droplets ejected from the nozzle 33, and the larger diameter dots G1 to G4 are formed. That is, the dots have a relationship of G1> G2> G3> G4.

Also in the second embodiment, the specific operations of the switch selection unit 44 and the drop number selection unit 45 are the same as those in the first embodiment.
Therefore, also in the second embodiment, since the ink droplet amount per pixel can be set finely, the same operational effects as those in the first embodiment can be obtained. In addition, in the second embodiment, since only one type of drive voltage is generated by the drive voltage generation unit 461, the drive voltage generation unit 461 has more than one type. There exists an effect which can simplify a composition.

  In the second embodiment, the rise time and fall time of the drive pulse signal can be varied, and the number of ink droplets ejected is determined for each nozzle based on the data per pixel for that nozzle. A time and a fall time are selected, and drive pulse signals that require the selected rise time and fall time are generated for the determined number of ejections and applied to the actuator of the ink chamber in which the nozzle is formed. I made it. However, according to the present invention, either the rising time or the falling time can be selected, and for each nozzle, the number of ink droplets to be ejected is determined based on data per pixel for the nozzle, and the rising time or the falling time is determined. A drive pulse signal that requires the selected rise time or fall time may be generated for the determined number of ejections and applied to the actuator of the ink chamber in which the nozzle is formed. .

  Further, the present invention is not limited to application to a piezo-type ink jet printer, and includes a heating element as a driving element, and the heating element to which the driving pulse signal is applied generates heat in the ink chamber and is discharged into the ink chamber. The present invention can also be applied to a thermal ink jet printer that generates driving bubbles.

1 is a block diagram illustrating a schematic configuration of an inkjet printer according to an embodiment of the present invention. Sectional drawing which shows the principal part structure of the inkjet head in the embodiment. AA sectional drawing in FIG. The schematic diagram which shows the data structure per pixel of the discharge data in the embodiment. FIG. 3 is a block diagram showing a main configuration of the ink jet recording apparatus according to the embodiment. The figure which shows an example of the circuit formed in a drive signal production | generation part corresponding to each of the several actuator which comprises the inkjet head in the embodiment. FIG. 4 is a schematic diagram showing a relationship between a drive voltage of a drive pulse signal and a dot diameter when the drive pulse signal is applied in the embodiment. The timing waveform figure of the principal part signal in the switch selection part of the embodiment. The timing waveform figure of the principal part signal in the drop number selection part of the embodiment. The wave form diagram which shows an example of the drive pulse signal applied to an actuator in the embodiment. The block diagram which shows the principal part structure of the inkjet recording device in the 2nd Embodiment of this invention. The figure which shows an example of the circuit formed in a drive signal production | generation part corresponding to each of the some actuator which comprises the inkjet head in the said 2nd Embodiment. The schematic diagram which shows the relationship between the waveform of a drive pulse signal, and the dot diameter when the drive pulse signal is applied in the said 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 11 ... Inkjet head, 12 ... Inkjet head drive device, 31 ... Ink chamber, 33 ... Nozzle, ACT ... Actuator, 41 ... Shift register, 42 ... Latch circuit, 43 ... Reference pulse generation circuit, 44 ... Switch Selection unit, 45 ... Drop number selection unit, 46, 461 ... Drive voltage generation unit, 47, 471 ... Drive pulse signal generation unit, 50, 501 ... Drive pulse signal generation circuit.

Claims (4)

A plurality of ink chambers for storing ink therein, nozzles formed in communication with the respective ink chambers, and a plurality of drive elements provided corresponding to the respective ink chambers and configured to eject the ink from the nozzles; In a method for driving an inkjet head comprising:
The drive voltage of the drive pulse signal can be varied,
For each nozzle, the number of ink droplets to be ejected is determined on the basis of data per pixel for that nozzle, and a driving voltage is selected. A driving pulse signal of the selected voltage is generated for the determined number of ejections. The ink jet head driving method, wherein the ink is applied to the driving element of the ink chamber in which the nozzle is formed. A plurality of ink chambers for storing ink therein, nozzles formed in communication with the respective ink chambers, and a plurality of drive elements provided corresponding to the respective ink chambers and configured to eject the ink from the nozzles; In a method for driving an inkjet head comprising:
The rise time or fall time of the drive pulse signal can be varied,
For each of the nozzles, the number of ink droplets to be ejected is determined based on data per pixel for the nozzle and a rise time or fall time is selected, and a drive pulse signal that requires the selected rise time or fall time. Is generated for the determined number of ejections and applied to the drive element of the ink chamber in which the nozzle is formed. A plurality of ink chambers for storing ink therein, nozzles formed in communication with the respective ink chambers, and a plurality of drive elements provided corresponding to the respective ink chambers and configured to eject the ink from the nozzles; In an inkjet head drive device comprising:
Drive voltage varying means for varying the drive voltage of the drive pulse signal;
Discharge number determining means for determining the discharge number of ink droplets for each nozzle based on data per pixel for the nozzle;
Drive voltage selection means for selecting a drive voltage within a range variable by the drive voltage variable means for each nozzle based on data per pixel for the nozzle;
Drive signal generation means for generating the drive pulse signal of the voltage selected by the drive voltage selection means for the number of ejections determined by the ejection number determination means;
An ink-jet head drive device comprising: A plurality of ink chambers for storing ink therein, nozzles formed in communication with the respective ink chambers, and a plurality of drive elements provided corresponding to the respective ink chambers and configured to eject the ink from the nozzles; In an inkjet head drive device comprising:
Drive time variable means for varying the rise time or fall time of the drive pulse signal;
Discharge number determining means for determining the discharge number of ink droplets for each nozzle based on data per pixel for the nozzle;
Drive time selecting means for selecting, for each nozzle, a rise time or fall time within a range that is varied by the drive time varying means based on data per pixel for the nozzle;
Drive signal generation means for generating drive pulse signals that require the rise time or fall time selected by the drive time selection means for the number of ejections determined by the ejection number determination means;
An ink-jet head drive device comprising:

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