JP2010240849A - Driving signal setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving signal setting method suitable for highly accurately setting a driving signal in accordance with nozzle characteristics. <P>SOLUTION: The driving signal setting method is used for performing corrections by a predetermined amount of shift on driving voltages VhA, VhB, VhC and VhD corresponding to respective groups A-D selected by the step S7 (S8 in Fig.7). Namely, on the selected driving voltages VhA, VhB, VhC and VhD, they are multiplied by specified shift correction factors, to finely adjust the voltage values to be loaded applicable to respective nozzles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

   The present invention relates to a drive signal setting method in a liquid discharge head.

   In recent years, a method has been proposed in which a liquid containing a functional material is discharged from a minute nozzle onto a substrate, and the liquid disposed on the substrate is solidified to form a thin film. Typical examples of the thin film include a color filter, a light emitting layer of an organic EL panel, a metal wiring, and the like.

   In such a method, in order to form a high-quality thin film, the amount of liquid to be discharged (hereinafter referred to as discharge amount) is required to be uniform among a large number of nozzles. This is because the variation in the discharge amount causes unevenness in the arrangement amount of the liquid and hinders the formation of a uniform thin film.

   In view of this, a technique has been proposed that compensates for variations in the discharge amount between nozzles by appropriately setting and supplying drive signals of a plurality of conditions corresponding to step changes in the discharge amount for each nozzle (drive element) (for example, Patent Document 1). However, even if an attempt is made to set an independent drive signal for each nozzle, there are restrictions on the types (systems) of drive signals that can actually be set due to problems in hardware configuration and control.

   For this reason, for example, a technique has been proposed in which a plurality of nozzles are grouped by arrangement position and an appropriate drive signal is supplied to each group (for example, Patent Document 2).

JP-A-9-17483 JP 2008-276088 A

   However, in general, in a liquid discharge head in which a large number of nozzles are arranged in one direction, the discharge amount tends to increase in the nozzles arranged near both sides rather than the nozzles arranged near the center. In particular, the discharge amount of the nozzles arranged at both ends greatly jumps up. For this reason, as described above, in the method of grouping a plurality of nozzles by arrangement position and supplying a drive signal for each group, it is not possible to completely suppress the jumping of the nozzle discharge amount near both ends, Some head characteristics could not fall within the appropriate standards.

   Some aspects of the present invention have been made in view of the above circumstances, and an object thereof is to provide a driving signal setting method suitable for setting a driving signal according to the characteristics of a nozzle with high accuracy. Yes.

In order to solve the above problems, some aspects of the present invention provide the following drive signal setting method.
That is, the drive signal setting method of the present invention provides a drive signal supplied to the drive element when a liquid is ejected from the nozzle in a liquid discharge head comprising a plurality of nozzles and a drive element provided for each nozzle. A drive signal setting method for setting the conditions of
(A) A step of classifying the plurality of nozzles into a plurality of groups on the basis of the discharge amount relating to the supply of the drive signal under a predetermined condition;
(B) B step of calculating an appropriate condition of the drive signal corresponding to each group based on the statistical value of the discharge amount related to the group;
(C) C step for selecting one of the appropriate conditions corresponding to each of the plurality of groups for each nozzle;
(D) At least a D step that is set after correcting the selected value selected for each nozzle with a preset shift amount is provided.

In the C step, it is preferable to select and set a condition corresponding to the group related to the statistical value closest to the discharge amount of the nozzle among appropriate conditions corresponding to the plurality of groups.
Further, it is preferable that each of the plurality of groups is constituted by a substantially equal number of nozzles.

It is preferable that the statistical value of the discharge amount related to the group is an average value of the discharge amount of the nozzles in the group.
Moreover, it is also preferable that the statistical value of the discharge amount related to the group is a median value of the discharge amount of the nozzles in the group.
Furthermore, it is preferable that the condition of the drive signal is a voltage component of the drive signal.

It is a perspective view which shows the principal part structure of a liquid discharger. It is a top view which shows the arrangement configuration of the head in a head unit. It is a top view which shows the relationship between the scanning locus | trajectory of a nozzle, and a discharge target object. It is a figure which shows the electrical constitution of the liquid discharge apparatus concerning a head drive. It is a timing diagram of a drive signal and a control signal. It is a block diagram which shows the apparatus structure for setting a drive signal. It is a flowchart which shows the processing flow for a drive signal setting. It is a figure which shows distribution of the discharge amount for every nozzle, group classification, and shift correction.

(Mechanical configuration and mechanical operation of liquid ejection device)
First, the mechanical configuration and operation of the liquid ejection apparatus according to the present invention will be described with reference to FIG. 1, FIG. 2, and FIG.
FIG. 1 is a perspective view showing a configuration of a main part of the liquid ejection apparatus. FIG. 2 is a plan view showing the arrangement of the heads in the head unit. FIG. 3 is a plan view showing the relationship between the scanning trajectory of the nozzle and the discharge target.

   A liquid ejection apparatus 200 shown in FIG. 1 is moved in the main scanning direction by a pair of linearly provided guide rails 201, an air slider and a linear motor (not shown) provided inside the guide rails 201. A main scanning moving table 203 is provided. Further, a pair of guide rails 202 linearly provided so as to be orthogonal to the guide rail 201 above the guide rail 201, an air slider and a linear motor (not shown) provided inside the guide rail 202, and A sub-scanning moving table 204 that moves in the sub-scanning direction is provided.

   On the main scanning moving table 203, a stage 205 for placing a substrate P as an ejection target is provided. The stage 205 is configured to suck and fix the substrate P, and the rotation mechanism 207 can accurately align the reference axis in the substrate P with the main scanning direction and the sub-scanning direction.

   The sub-scanning moving table 204 includes a carriage 209 that is attached in a suspended manner via a rotation mechanism 208. The carriage 209 includes a head unit 10 including heads 11 and 12 (see FIG. 2) as liquid discharge heads, a liquid supply mechanism (not shown) for supplying liquid to the heads 11 and 12, and the head 11. , 12 is provided with a control circuit board 30 (see FIG. 4).

   As shown in FIG. 2, the head unit 10 includes heads 11 and 12 that discharge liquid from nozzles n. The head unit 10 according to this embodiment is used for forming a color filter of a display panel, and the heads 11 and 12 correspond to red (R), green (G), and blue (B) color elements, respectively. A device for discharging liquid is prepared. In addition, the head 11 and the head 12 are arranged so as to be displaced from each other in the sub-scanning direction, and have a relationship of complementing the dischargeable range.

   A plurality (60 in this embodiment) of nozzles n in the heads 11 and 12 are arranged in a line at a predetermined pitch (for example, 180 dpi), and constitute nozzle arrays 21A and 21B. The direction of arrangement of the nozzles n in the nozzle arrays 21A and 21B is made to coincide with the sub-scanning direction, and the nozzles n of the nozzle arrays 21A and 21B are in a staggered arrangement with each other.

   In the heads 11 and 12, liquid chambers (hereinafter referred to as cavities) communicating with the respective nozzles n are formed, and in each of the cavities, drive elements for driving the movable walls to vary the volume. A piezoelectric element 16 (see FIG. 4) is disposed. Then, by supplying an electrical signal (hereinafter referred to as a drive signal) to the piezoelectric element 16 and controlling the fluid pressure in the cavity, it is possible to eject a droplet (liquid) from the nozzle n.

   Here, as an example of the operation of the liquid ejecting apparatus 200, an operation when color filters are manufactured will be described. When the heads 11 and 12 are scanned in the main scanning direction with respect to the substrate P, the nozzle n draws a scanning locus with a predetermined pitch (for example, 360 dpi) continuous with respect to the substrate P as shown in FIG. At this time, several nozzles n (three in this embodiment) of the nozzle arrays 21A and 21B are used as dummy nozzles that are not used in view of the peculiarities of the characteristics (illustrated and illustrated). The scanning area applied to the dummy nozzle of the head 11 is complemented by the nozzle n of the head 12, and the scanning area applied to the dummy nozzle of the head 12 is complemented by the nozzle n of the head 11.

   On the substrate P to be used for color filter formation, a bank 51 that defines a partition area 50 corresponding to each pixel area is formed in advance using a photosensitive resin or the like. In this case, with respect to the scanning trajectory, there are nozzles n that can be applied to the partitioned area 50 and nozzles n that cannot be applied, but the liquid is placed in the partitioned area 50 by ejecting the liquid from the nozzle n that can be applied to the partitioned area 50. Will be done by.

   A1 to A5, B1 to B5, C49 to C54, and D49 to D54 attached to the nozzles n in FIG. The nozzle numbers of the nozzle array 21B of the head 12 are shown. Here, the nozzle number is a serial number indicating the arrangement order of the nozzles n in the arrangement direction of the nozzle arrays 21A and 21B. In this embodiment, 1 to 54 excluding dummy nozzles per nozzle array. The nozzle number can be indicated.

   In FIG. 3, the nozzles n having nozzle numbers D53, C54, D54, A1, and B1 can discharge liquid to the same partition region 50 in appropriate periods during the scanning. Further, the nozzles n of nozzle numbers C50, C53, A2 and A5 do not discharge liquid during the entire scanning period because the scanning locus is on the bank 51. Such discharge / non-discharge control for each nozzle n is performed by switching the supply of a drive signal to the corresponding piezoelectric element 16 (details will be described later).

   Note that the configuration of the liquid ejection device is not limited to the above-described aspect. For example, the arrangement direction of the nozzle arrays 21A and 21B can be inclined from the sub-scanning direction so that the pitch of the scanning trajectory of the nozzles n is narrower than the pitch between the nozzles n in the nozzle arrays 21A and 21B. . Further, the number of heads 11 and 12 in the head unit 10 and the arrangement configuration thereof can be changed as appropriate. Further, as a driving method of the heads 11 and 12, for example, a so-called thermal method in which a heating element is provided in the cavity can be adopted.

(Electrical configuration and electrical operation of liquid ejection device)
Next, the electrical configuration and operation of the liquid ejection apparatus according to the present invention will be described with reference to FIGS.
FIG. 4 is a diagram illustrating an electrical configuration of a liquid ejection apparatus according to head driving. FIG. 5 is a timing diagram of the drive signal and the control signal.

   As shown in FIG. 4, the head 11 (12) includes a piezoelectric element 16 provided for each nozzle n (see FIG. 2) of the nozzle array 21A (21B) and a drive signal (COM) to each piezoelectric element 16. A switching circuit 17 for switching between supply / non-supply and a drive signal selection for selecting a drive signal supply line (hereinafter referred to as COM lines (COM1 to COM4)) related to the supply to each piezoelectric element 16 And a circuit 18. The head 11 (12) is electrically connected to the control circuit board 30.

   The control circuit board 30 includes D / A converters (DACs) 31A to 31D that generate independent drive signals (COM), and slew rate data (hereinafter referred to as drive signal (COM)) generated by the D / A converters 31A to 31D. , A waveform data selection circuit 32 having a storage memory for waveform data (WD1 to WD4) inside, and a data memory 33 for storing discharge control data received from the outside. The drive signals generated by the D / A converters 31A to 31D are output to the COM lines (COM1 to COM4) on the control circuit board 30, respectively.

   In the nozzle array 21A (21B), one electrode 16c of the piezoelectric element 16 is connected to a ground line (GND) of the D / A converters 31A to 31D. The other electrode of the piezoelectric element 16 (hereinafter referred to as segment electrode 16s) is connected to the COM lines (COM1 to COM4) via the switching circuit 17 and the drive signal selection circuit 18. The switching circuit 17, the drive signal selection circuit 18, and the waveform data selection circuit 32 are inputted with a clock signal (CLK) and a latch signal (LAT) corresponding to each ejection timing.

   The data memory 33 stores the following data for each ejection timing that is periodically set according to the scanning position of the head 11 (12). That is, discharge data (SIA) that regulates switching of supply / non-supply (ON / OFF) of a drive signal (COM) to each piezoelectric element 16 and COM lines (COM1 to COM4) corresponding to each piezoelectric element 16 are displayed. Drive signal selection data (SIB) to be defined and waveform number data (WN) to define the types of waveform data (WD1 to WD4) input to the D / A converters 31A to 31D. In this embodiment, the discharge data (SIA) is 1 bit (0, 1) per nozzle, and the drive signal selection data (SIB) is 2 bits (0, 1, 2, 3) per nozzle. The waveform number data (WN) is composed of 7 bits (0 to 127) per 1D / A converter. Note that these data structures can be changed as appropriate.

   In the above-described configuration, drive control related to each ejection timing is performed as follows. That is, during the period from timing t1 to t2 shown in FIG. 5, the ejection data (SIA), drive signal selection data (SIB), and waveform number data (WN) are converted into serial signals, respectively, and the switching circuit 17 and drive signal selection are performed. The data is transmitted to the circuit 18 and the waveform data selection circuit 32. Then, each data is latched at timing t2, so that the segment electrode 16s of each piezoelectric element 16 related to ejection (ON) is applied to each COM line (COM1 to COM4) designated by the drive signal selection data (SIB). Connected. For example, when the drive signal selection data (SIB) is 0, 1, 2, 3, the segment electrodes 16s of the corresponding piezoelectric element 16 are connected to COM1, COM2, COM3, COM4, respectively. Further, waveform data (WD1 to WD4) of drive signals related to the generation of the D / A converters 31A to 31D are set.

   In each period of timing t3 to t4, t4 to t5, and t5 to t6, a drive signal (COM) is generated in a series of steps of increasing potential, maintaining potential, and decreasing potential according to the waveform data set at timing t2. The Then, the generated drive signal is supplied to the piezoelectric elements 16 connected to COM1 to COM4, respectively, so that the volume (pressure) of the cavity communicating with the nozzle is controlled.

   Here, the potential increasing component at the timings t3 to t4 expands the cavity and plays a role of drawing the liquid inward of the nozzle. In addition, the potential drop component at the timings t5 to t6 plays a role of contracting the cavity and pushing the liquid out of the nozzle to be discharged.

   The time component and the voltage component related to the potential increase, potential retention, and potential decrease in the drive signal (COM) depend closely on the discharge amount of the liquid discharged by the supply. In particular, in the piezoelectric head, since the discharge amount exhibits a good linearity with respect to the change of the voltage component, the voltage difference at timings t3 to t6 is defined as the drive voltage Vh, and this is used as the discharge amount control condition. can do. That is, the drive voltage Vh corresponds to the “drive signal condition” in the present invention. The drive signal (COM) to be generated is not limited to a simple trapezoidal wave as shown in the present embodiment, and various known shapes can be adopted as appropriate. Further, when a different driving method (for example, a thermal method) is adopted, the pulse width (time component) of the driving signal can be used as a condition for controlling the ejection amount.

   In the present embodiment, a plurality of types of waveform data having different drive voltages Vh are prepared, and independent waveform data (WD1 to WD4) are input to the D / A converters 31A to 31D, respectively. It is possible to output drive signals (COM) having different drive voltages Vh to (COM1 to COM4). The types of waveform data that can be prepared are 128 types corresponding to the information amount (7 bits) of the waveform number data (WN), for example, corresponding to the drive voltage Vh in increments of 0.1V.

   Thus, the liquid ejection apparatus 200 according to the present embodiment includes the drive signal selection data (SIB) that defines the correspondence between each piezoelectric element 16 (nozzle) and the COM line (COM1 to COM4), and each COM line (COM1 to COM4). ) And the waveform number data (WN) that defines the correspondence relationship between the drive signal type (drive voltage Vh) and the liquid can be discharged with an appropriate discharge amount. In other words, the proper setting of the drive signal for each nozzle determined by the relationship between the drive signal selection data (SIB) and the waveform number data (WN) is an important matter for managing the discharge amount. It can be said that there is. Note that the liquid ejection apparatus 200 according to the present embodiment is configured to be able to update the drive signal selection data (SIB) and the waveform number data (WN) at each ejection timing, and therefore corresponds to changes in the ejection data (SIA). It is also possible to set the drive signal finely.

(Drive signal setting method)
Next, the drive signal setting method of the present invention, that is, a method for setting appropriate conditions (drive voltage Vh) of the drive signal of each nozzle will be described with reference to FIGS. To do.
FIG. 6 is a block diagram showing an apparatus configuration for setting a drive signal. FIG. 7 is a flowchart showing a processing flow for setting a drive signal. FIG. 8 is a diagram showing the distribution of discharge amounts and group classification for each nozzle.

   In FIG. 6, a setting device 300 for setting a drive signal includes a liquid supply device 301 for supplying a liquid to the head 11 (12) and a control circuit board 302 for driving the head 11. Yes. Further, a liquid receiving container 303 for receiving and storing the liquid discharged from the head 11 and a weight measuring device 304 for measuring the weight of the liquid receiving container 303 are provided. Further, a liquid receiving substrate 305 that receives the liquid ejected from the head 11, a substrate moving device 306 for moving the liquid receiving substrate 305 in the substrate surface direction, and a volume of the liquid disposed on the liquid receiving substrate 305 are measured. And a volume measuring device 307 for performing the above. Further, the driving of the head 11 is controlled via the control circuit board 302, the driving of the substrate moving device 306 is controlled, the weighing operation of the weight measuring device 304 and the volume measuring device 307 is controlled, and the calculation is performed based on the measurement result. A personal computer (PC) 308 is provided.

   The control circuit board 302 has the same configuration as the control circuit board 30 (see FIG. 4). The liquid receiving container 303 may be made of any material that does not erode by the liquid. However, the liquid receiving container 303 is configured to suppress the volatilization of the liquid by disposing a porous member such as a sponge in the opening. Is preferred. In addition, a general electronic balance can be used for the weight weighing device 304. As the volume measuring device 307, a three-dimensional shape measuring device using a white interference method can be used.

   As described above, the setting device 300 can measure the discharge amount as a weight or a volume by using two types of measuring devices, the weight measuring device 304 and the volume measuring device 307. The weight measuring device 304 is suitable for measuring the average discharge amount in the entire nozzle array with high speed and high accuracy, and the volume measuring device 307 is suitable for measuring the discharge amount of each nozzle.

   In a state where the head 11 is attached to the setting device 300, first, the average discharge amount of all nozzles (excluding dummy nozzles) in the nozzle array is measured (step S1 in FIG. 7). Specifically, ejection is performed for a number of times (for example, 100,000 times) for each nozzle, the total weight is measured by the weight weighing device 304, and the measurement result is divided and measured. This measurement is performed under two conditions of driving voltage Vh (for example, 20 V and 30 V).

   Next, the relationship between the drive voltage Vh and the average discharge amount under the two measured conditions is linearly complemented to calculate the reference drive voltage Vs for obtaining the average discharge amount of the reference discharge amount (design value corresponding to the specification). (Step S2 in FIG. 7). Further, the change rate of the average discharge amount with respect to the drive voltage Vh is calculated as a correlation coefficient α when the discharge amount is corrected by the drive voltage Vh (step S3 in FIG. 7).

   Next, a drive signal of drive voltage Vh = Vs is supplied to all the piezoelectric elements of the nozzle array, the liquid is discharged onto the liquid receiving substrate 305, and the discharge amount is measured (step S4 in FIG. 7). Since the surface of the liquid receiving substrate 305 is subjected to a liquid repellent treatment, the liquid discharged from each nozzle forms independent hemispherical droplets on the substrate. The three-dimensional shape of the droplet is measured by the volume measuring device 307, and the measurement data is analyzed by the personal computer 308, whereby the discharge amount can be obtained. In addition, since the discharge amount per one time of each nozzle is extremely small, in order to increase the accuracy of the volume measurement (discharge amount measurement) of the droplets, the discharge of each nozzle is carried out a plurality of times (for example, overlapping the same location on the substrate) 3 times).

When indicating a discharge amount of each nozzle measured in step S4 as a spatial distribution in the arrangement direction of the nozzles array is shown in FIG. 8 (discharge amount is represented by a relative ratio with respect to the reference discharge amount q _0). As shown in the figure, in the case of the head according to the present embodiment, the discharge amount tends to be relatively large near the end of the nozzle array, and the discharge amount tends to be relatively small near the center of the nozzle array.

   Next, group setting of each nozzle is performed based on the measurement in step S4 (step S5 in FIG. 7). That is, step S5 constitutes step A of the present invention. In the present embodiment, according to the order of the measured discharge amount (the higher discharge amount is the upper level and the lower discharge amount is the lower level), the 14 nozzles are arranged in order from the lowest to the higher level of group A and group A. The 14 nozzles are classified as group B, the upper 13 nozzles of group B are classified as group C, and the upper 13 nozzles of group C are classified as group D, respectively.

Next, an appropriate drive voltage Vh (hereinafter referred to as an appropriate drive voltage VhA, VhB, VhC, VhD) corresponding to the groups A to D is calculated (step S6 in FIG. 7). Although the condition of “appropriate” can be freely defined, in the present embodiment, the appropriate drive voltage VhA to match the statistical value of the discharge amount related to the groups A to D with the reference discharge amount q ₀ , respectively. VhD is calculated based on the measured value of the ejection amount in step S4, the correlation coefficient α, and the reference drive voltage Vs. That is, step S6 constitutes step B of the present invention.

Here, the statistical value of the discharge amount related to the groups A to D refers to a numerical value obtained from the statistics of the discharge amount of a plurality of nozzles included in each group, and in this embodiment, included in each group. This is the average value of the nozzle discharge amount. As a result, stepwise appropriate drive voltages VhA to VhD are obtained for discharging liquids having an average drop amount (reference discharge amount q ₀ ) from the nozzles of groups A to D, respectively. In addition, you may make it perform step S6 by making the median value of the discharge amount of the nozzle contained in each group into the statistical value of the discharge amount which concerns on a group.

   The appropriate drive voltages VhA, VhB, VhC, and VhD in this embodiment are defined as relative ratios with respect to the reference drive voltage Vs, and are 101.8%, 100.7%, 99.4%, and 97, respectively. .9%. In this way, by defining the appropriate drive voltage as a relative ratio, for example, when a situation occurs where the liquid viscosity changes and the discharge amount changes uniformly, the average discharge amount of the entire nozzle array is measured. Thus, there is an advantage that the reference drive voltage Vs only needs to be reset.

   Next, one of the appropriate drive voltages VhA, VhB, VhC, and VhD is selected for each nozzle as the drive voltage Vh corresponding to each nozzle (step S7 in FIG. 7). That is, step S7 constitutes step C of the present invention. The appropriate drive voltages VhA, VhB, VhC, and VhD can be made to correspond to the four COM lines (COM1 to COM4 (see FIG. 4)), respectively, in the drive control.

   When setting the drive voltage Vh corresponding to each nozzle, a method of collectively setting appropriate drive voltages corresponding to the group for each group is also conceivable. However, a group having a relatively wide discharge amount distribution range such as group B and group D includes nozzles having a discharge amount far from the statistical values. Setting an appropriate drive voltage based on group statistics is not necessarily a preferred method.

   Therefore, in the present embodiment, for each nozzle, among the four appropriate drive voltages corresponding to each group, the one corresponding to the group related to the statistical value closest to the discharge amount of the nozzle is selected and set. Thereby, the drive signal according to the characteristic of the nozzle can be set with higher accuracy.

   In the example of FIG. 8, the appropriate drive voltage VhA is set for all the nozzles in the group A. In the case of group B nozzles, the appropriate drive voltage VhB is set for many nozzles. For example, the appropriate drive voltage VhC is set for the nozzle of nozzle number 8 and the appropriate drive voltage VhA is set for the nozzle of nozzle number 15. The As described above, in a group having a relatively wide distribution range of the discharge amount, an appropriate drive voltage corresponding to the group related to the preceding and following order is set for the nozzle near the boundary with the group related to the preceding and following order. Sometimes.

   Next, the drive voltages VhA, VhB, VhC, and VhD that are selected in step S7 and correspond to the groups A to D are corrected by a predetermined shift amount (step S8 in FIG. 7). That is, the selected drive voltages VhA, VhB, VhC, and VhD are multiplied by a predetermined shift correction coefficient, and the applied voltage value applied to each nozzle is finely adjusted.

   In this case, in the case of the head according to the present embodiment, the discharge amount tends to jump up near the end of the nozzle array, and simply applying the drive voltages VhA, VhB, VhC, and VhD selected in step S7 will cause an end. This is because there is a possibility that the discharge amount of the nozzle arranged in the vicinity of the part deviates from a specified range (predetermined head characteristic standard).

   When such shift correction of the drive voltages VhA, VhB, VhC, and VhD is performed, in the example of FIG. 8, for the nozzles in the group A, VhA + to VhA− that are plus or minus by a predetermined shift range from the drive voltage VhA. It is set to an appropriate value within the range. In the case of group B nozzles, an appropriate value is set in a range of VhB + to VhB− that is plus or minus a predetermined shift range from the drive voltage VhB. Similarly, VhC and VhD are also set to appropriate values within the range of VhC + to VhC− and the range of VhD + to VhD−, respectively, plus or minus by a predetermined shift range.

   As described above, the driving voltages VhA, VhB, VhC, and VhD selected to correspond to each of the groups A to D are arranged in the vicinity of the end portions by performing correction by a predetermined shift amount. Even a head having a characteristic in which the discharge amount of the nozzle jumps up can satisfy a predetermined head characteristic standard. Then, for example, if a light emitting layer of a color filter or an organic EL panel is formed using the head driven by the driving signal setting method of the present invention, the variation in the discharge amount is flattened and a uniform thin film is formed. It becomes possible.

   The group classification method described above, in particular, the number of nozzles constituting each group is not necessarily limited to the above-described mode. However, since the drive voltage Vh is set according to the group unit, the number of nozzles corresponding to each appropriate drive voltage, that is, each COM line is obtained by making the number of nozzles constituting each group substantially equal. It is possible to make it difficult to generate an imbalance. Since the corresponding number of nozzles in the COM line affects the distortion of the drive signal and the like, it is preferable that an imbalance between the COM lines does not occur as much as possible. The above-described embodiment has been made in view of this point. is there.

The present invention is not limited to the above-described embodiment.
For example, as another example of the liquid arrangement using the liquid discharge head according to the present invention, for example, formation of a fluorescent film in a plasma display device, formation of an element film in an organic EL display, or conductive wiring or resistance element in an electric circuit And the like.
Moreover, each structure of embodiment can combine these suitably, can be abbreviate | omitted, or can combine with the other structure which is not shown in figure. Hereinafter, an embodiment of a liquid ejection head evaluation method of the present invention will be described. The present embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for convenience, and the dimensional ratio of each component is the same as the actual one. Not necessarily.

DESCRIPTION OF SYMBOLS 11, 12 ... Head as a liquid discharge head, 16 ... Piezoelectric element as a drive element, 17 ... Switching circuit, 18 ... Drive signal selection circuit, 21A, 21B ... Nozzle array, 30 ... Control circuit board, 31A-31D ... D / A converter, 32 ... waveform data selection circuit, 300 ... setting device, 301 ... liquid material supply device, 302 ... control circuit board, 303 ... liquid material receiving container, 304 ... weight measuring device, 305 ... liquid material receiving substrate, 306 ... Substrate moving device, 307 ... Volume measuring device, 308 ... Personal computer, n ... Nozzle, COM1 to COM4 ... COM line (drive signal supply line).

Claims (6)

In a liquid discharge head including a plurality of nozzles and a drive element provided for each nozzle, a drive signal setting method for setting a condition of a drive signal supplied to the drive element when liquid is discharged from the nozzle. And
(A) A step of classifying the plurality of nozzles into a plurality of groups on the basis of the discharge amount relating to the supply of the drive signal under a predetermined condition;
(B) B step of calculating an appropriate condition of the drive signal corresponding to each group based on the statistical value of the discharge amount related to the group;
(C) C step for selecting one of the appropriate conditions corresponding to each of the plurality of groups for each nozzle;
(D) a D step that is set after correcting the selected value selected for each nozzle with a preset shift amount;
A drive signal setting method, comprising:    The C step includes selecting and setting an appropriate condition corresponding to each of the plurality of groups corresponding to the group related to the statistical value closest to the discharge amount of the nozzle. 1. The drive signal setting method according to 1.    3. The drive signal setting method according to claim 1, wherein each of the plurality of groups includes a substantially equal number of nozzles.    4. The drive signal setting method according to claim 1, wherein the statistical value of the discharge amount related to the group is an average value of the discharge amount of the nozzles in the group. 5.    4. The drive signal setting method according to claim 1, wherein the statistical value of the discharge amount related to the group is a median value of the discharge amount of the nozzles in the group. 5. 6. The drive signal setting method according to claim 1, wherein the condition of the drive signal is a voltage component of the drive signal.

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