JP2008284697A - Test ejection method and test ejection pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test ejection method and a test ejection pattern which can facilitate checking of kinds of driving signals respectively assigned to a plurality of driving elements. <P>SOLUTION: An ejection head has a plurality of nozzles n and the plurality of driving elements divided to a plurality of groups, and moreover has the driving signals different in type for every group assigned to the plurality of driving elements. The ejection head carries out the step of supplying the driving signal assigned to an object group made an object to eject liquid droplets among one of the plurality of groups to each of the driving elements which belong to the object group, and at the same time supplying the driving signal of the type that suppresses ejection of the liquid droplets to each of the driving elements which belong to the remaining groups, for all of the plurality of groups while changing the group to be the object group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a test ejection method and a test ejection pattern.

  Conventionally, in an ink jet recording head, a method of performing gradation expression by selectively supplying one drive signal to an actuator (drive element) from a plurality of types of drive signals having different ejection amounts is known. (For example, refer to Patent Document 1).

JP-A-9-17483

In recent years, a method of forming a thin film by discharging a liquid material containing a functional material from a plurality of nozzles to a substrate and solidifying the liquid material arranged on the substrate has been utilized. Examples of the thin film include a color filter of a liquid crystal display device, a light emitting layer of an organic EL (Electro Luminescence) device, and a metal wiring.
In such a method, from the viewpoint of forming a high-quality thin film, it is preferable that the variation in the discharge amount of the liquid material is small between the plurality of nozzles. This is because if the variation in the discharge amount is large, unevenness in the arrangement amount of the liquid material is likely to occur, making it difficult to form a homogeneous thin film.

  In order to reduce the variation in the discharge amount among the plurality of nozzles, the method described in Patent Document 1 can be used. In this case, one of a plurality of types of drive signals is assigned to each drive element corresponding to each of the plurality of nozzles. A drive signal that increases the discharge amount is assigned to a drive element corresponding to a nozzle with a small discharge amount, and a drive signal that assigns a discharge amount is assigned to a drive element that corresponds to a nozzle with a large discharge amount. Thus, variation in the discharge amount can be reduced. Assignment of each drive waveform to each drive element can be achieved by fixedly setting the gradation data described in Patent Document 1 corresponding to each drive element.

  By the way, in the ink jet recording head, one of methods for confirming whether or not ink is being ejected from a plurality of nozzles is test ejection. In this test ejection, ink is ejected from a plurality of nozzles onto a test medium such as paper, and it is confirmed whether or not ink is ejected from the plurality of nozzles. A nozzle that does not eject ink among the plurality of nozzles can be recognized as a so-called ejection failure from the result of the test ejection.

  On the other hand, whether or not an appropriate drive signal is assigned to each drive element when test ejection is applied to a method of assigning one of a plurality of types of drive signals to each of the plurality of drive elements There is an unsolved problem that it is difficult to confirm.

  The present invention has been made paying attention to this unsolved problem, and it is possible to easily confirm the type of drive signal assigned to each of a plurality of drive elements, and a test discharge pattern. The purpose is to provide.

  In the test ejection method of the present invention, a plurality of nozzles for ejecting a liquid material as droplets, and the plurality of nozzles are provided corresponding to each of the plurality of nozzles, and the droplets are ejected from the nozzles upon receiving a drive signal. A test ejection method for performing test ejection on a medium with an ejection head having a plurality of driving elements, wherein the ejection head includes the plurality of nozzles and the plurality of driving elements on each of the nozzles and each of the nozzles. In a state where each corresponding drive element is paired, it is divided into a plurality of sets, and the drive signals of different types are assigned to the plurality of drive elements in units of the set, One of the plurality of groups is set as a target group for which the droplet is to be ejected, and the drive signal assigned to the target group is sent to each of the drive elements belonging to the target group. A step (a) of supplying the drive signal of a type that suppresses ejection of the droplets to each of the drive elements belonging to the remaining set, while changing the set as the target set, It is carried out over all of the plurality of sets.

This test discharge method is a discharge head in which a plurality of nozzles and a plurality of drive elements are divided into a plurality of sets, and different types of drive signals are assigned to the plurality of drive elements in units of sets. This is a test discharge method for performing discharge.
And this test discharge method makes one of a plurality of groups a target group, supplies a drive signal assigned to this target group to each drive element belonging to the target group, and each of the remaining groups A step (a) of supplying a drive signal for suppressing ejection of the droplets to the drive element;

  According to step (a), a drive signal is supplied to each of the plurality of drive elements. At this time, if a drive signal to be supplied to each drive element belonging to the target group is appropriately assigned, droplets are ejected from each nozzle belonging to the target group, and droplets are ejected from each nozzle belonging to the remaining group. Is not discharged. As a result, it is possible to grasp whether or not the drive signal is assigned to the target group.

  In this test ejection method, the above steps are performed over all of the plurality of sets while changing the set as the target set. Therefore, a test discharge result for each set is displayed on the medium. That is, it is possible to grasp whether or not the drive signals are assigned to all the sets from this medium. Therefore, in this test ejection method, it is possible to easily confirm the type of drive signal assigned to each of the plurality of drive elements, and whether or not an appropriate drive signal is supplied to each drive element. Can make it easier to check.

  In the test ejection method, the step (a) may be performed over all of the plurality of sets while changing a relative position between the ejection head and the medium.

  In this test ejection method, step (a) is performed while changing the relative position between the ejection head and the medium, so that the test ejection results for each group are displayed on the medium at different positions. This makes it easier to confirm the type of drive signal assigned to each of the plurality of drive elements.

  In the test ejection method, the plurality of nozzles may form a row, and the relative position may be changed in a direction intersecting the direction of the row.

  In this test ejection method, the relative position between the ejection head and the medium is changed in a direction that intersects the direction of the row formed by the plurality of nozzles. Expressed side by side in the direction that intersects the direction of the row. Thereby, it is possible to easily grasp the correspondence relationship between the test ejection result and each of the plurality of nozzles constituting the row.

  The test ejection method may include a step (b) of marking on the medium marks indicating the positions of the nozzles in the row.

  In this test ejection method, a mark indicating the positioning of each nozzle in the row is written on the medium. This makes it easier to grasp the correspondence between the test discharge result and each nozzle.

  In the test ejection method, the ejection head is provided corresponding to each of the plurality of input systems capable of receiving a plurality of different types of drive signals in parallel, and each of the plurality of input systems. A drive signal selection unit that outputs the drive signal input from the selected input system based on input selection data instructing that one of these should be selected, and corresponding to each of the drive elements A switch unit that is provided and receives the drive signal from the drive signal selection unit and outputs the drive signal to the drive element based on ejection data that permits output of the drive signal to the drive element; The plurality of drive elements are divided into the plurality of sets by associating each of the drive elements with any one of the plurality of input systems in the input selection data. In the step (a), the drive signal assigned to the target set is input to the input system corresponding to the target set, and the liquid is supplied to each input system corresponding to the remaining sets. The type of the drive signal that suppresses the ejection of droplets may be input, and the discharge data that permits the output of the drive signal to the drive elements may be input to the switch units.

  An ejection head to which this test ejection method can be applied has a plurality of input systems, a drive signal selection unit, and a switch unit. The plurality of input systems can accept a plurality of drive signals of different types in parallel. The drive signal selection unit is provided corresponding to each drive element, selects any one of a plurality of input systems based on input selection data, and outputs a drive signal from the selected input system. Output. The switch unit is provided corresponding to each drive element, and outputs the drive signal input from the drive signal selection unit to the drive element based on the ejection data. The plurality of drive elements provided in the ejection head are divided into a plurality of groups by associating each drive element with any one of the plurality of input systems using input selection data.

  In this test ejection method, in step (a), the drive signal assigned to the target group is input to the input system corresponding to the target group, and the liquid is input to each input system corresponding to the remaining groups. A type of drive signal that suppresses the ejection of droplets is input, and discharge data that permits output of each drive signal to each drive element is input to each switch unit. According to this step (a), a drive signal can be supplied to each of the plurality of drive elements. Here, if a drive signal to be supplied to each drive element belonging to the target group is appropriately assigned, droplets are ejected from each nozzle belonging to the target group, and droplets are ejected from each nozzle belonging to the remaining group. Is not discharged. As a result, it is possible to grasp whether or not the drive signal is assigned to the target group.

  The test ejection pattern of the present invention is provided corresponding to each of a plurality of nozzles that eject a liquid material as droplets and the plurality of nozzles, and the droplets are ejected from the nozzles upon receiving a drive signal. A test discharge pattern in which a discharge result obtained by performing test discharge on a medium with a discharge head having a plurality of drive elements is displayed, wherein the discharge head includes the plurality of nozzles and the plurality of drive elements, The nozzles and the drive elements corresponding to the nozzles are paired and divided into a plurality of groups, and the types of the plurality of drive elements are different in units of the groups. A drive signal is assigned, and the ejection result for each set is displayed on the medium at a different position for each set.

  In this test ejection pattern, the ejection results for each group are displayed at different positions for each group, so that it is possible to easily confirm the type of drive signal assigned to each of the plurality of drive elements.

  In the test discharge pattern, the plurality of nozzles constitute a row, and the discharge result for each set is arranged in the medium in a state in which the set is aligned in a direction intersecting the direction of the row for each set. It may be exposed.

  In this test ejection pattern, the ejection results for each group are displayed on the medium in a state in which the ejection results are arranged in a direction intersecting the column direction for each group. It is possible to make it easier to grasp the correspondence with each of the plurality of nozzles constituting the.

  In the test ejection pattern, a mark indicating the positioning of each nozzle in the row may be written on the medium.

  In this test ejection pattern, marks indicating the positioning of each nozzle in the row are marked, so that it is easier to grasp the correspondence between each set of ejection results and each of the plurality of nozzles constituting the row. it can.

Embodiments of the present invention will be described with reference to the drawings.
In addition, in this embodiment, various technically preferable limitations are given, but this embodiment is not limited to these forms unless there is a description that it is particularly limited in the following description. In the drawings referred to in the following description, the vertical and horizontal scales of members and parts may be expressed differently from actual ones for convenience of illustration.

(Mechanical configuration and mechanical operation of liquid material discharge device)
First, with reference to FIG. 1, FIG. 2, FIG. 3, the mechanical configuration and operation of the liquid material discharge apparatus in the present embodiment will be described.
FIG. 1 is a perspective view showing a configuration of a main part of the liquid material discharge apparatus. FIG. 2 is a bottom view showing the arrangement of the ejection 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.

  1 moves 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. Main scanning moving table 203. Further, the liquid material discharge device 200 includes 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 provided inside the guide rail 202. And a sub-scanning moving base 204 that moves in the sub-scanning direction by a motor (not shown).

  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. In addition, the carriage 209 includes a head unit 10 including discharge heads 11 and 12 (see FIG. 2), a liquid material supply mechanism (not shown) for supplying a liquid material to the discharge heads 11 and 12, and the discharge head 11. , 12 is provided with a control circuit board 30 (see FIG. 4).

  As shown in FIG. 2, each of the ejection heads 11 and 12 has a plurality of nozzles n that eject the liquid material as droplets. In the present embodiment, the head unit 10 is used for forming a color filter for a display panel. The discharge heads 11 and 12 are prepared to discharge a liquid corresponding to each color element of red (R), green (G), and blue (B). In addition, the ejection head 11 and the ejection head 12 are disposed so as to be displaced from each other in the sub-scanning direction, and are in a relationship of complementing the dischargeable range.

  Each of the ejection heads 11 and 12 is formed with two nozzle arrays 21A and 21B in which a plurality of nozzles n are arranged along the sub-scanning direction. In the present embodiment, each of the nozzle arrays 21A and 21B has a configuration in which 60 nozzles n are arranged in a line at a predetermined pitch (for example, 180 pitches per inch). In each of the ejection heads 11 and 12, the nozzles n of the nozzle array 21A and the nozzles n of the nozzle array 21B are in a staggered relationship with each other.

  A liquid chamber (not shown) (hereinafter referred to as a cavity) that communicates with each nozzle n is formed in each ejection head 11, 12. Each cavity is provided with a piezoelectric element 16 (see FIG. 4) as a driving element for driving the movable wall to change the volume. Then, by supplying an electric signal (hereinafter referred to as a drive signal) to the piezoelectric element 16 and controlling the pressure of the liquid material in the cavity, it is possible to discharge a droplet from the nozzle n.

  Here, as an example of the operation of the liquid material discharge device 200, an operation when color filters are manufactured will be described. When the ejection heads 11 and 12 are scanned in the main scanning direction with respect to the substrate P, the nozzles n have a predetermined pitch (for example, 360 dpi (Dot Per Inch)) continuous to the substrate P as shown in FIG. Draw a scanning trajectory. Here, several nozzles n (three in the present embodiment) at each end of each nozzle array 21A, 21B are dummy nozzles that are not used in view of the peculiarities of the characteristics (illustrated by painting). Yes. The scanning area applied to the dummy nozzle of the ejection head 11 is supplemented by the nozzle n of the ejection head 12. In addition, the scanning region applied to the dummy nozzles of the ejection head 12 is supplemented by the nozzles n of the ejection head 11.

  On the substrate P used for color filter formation, a bank 51 that defines a partition region 50 corresponding to each pixel region 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 partition region 50 and nozzles n that cannot be applied, but the liquid material is arranged in the partition region 50 according to the liquid material from the nozzle n that can be applied to the partition region 50. It will be performed by discharging.

  A1 to A5, B1 to B5, C49 to C54, and D49 to D54 attached to each nozzle n in FIG. 3 are the nozzle array 21A of the ejection head 11, the nozzle array 21B of the ejection head 11, and the ejection head 12, respectively. The nozzle numbers of the nozzle array 21A and the nozzle array 21B of the ejection 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, each of the nozzles n having nozzle numbers D53, C54, D54, A1, and B1 can eject the liquid material to the same partition region 50 in an appropriate period during the scanning. Further, each nozzle n of nozzle numbers C50, C53, A2 and A5 has a scanning locus on the bank 51, and therefore does not discharge the liquid material during the entire period during the scanning. Such discharge or 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 material discharge device 200 is not limited to the above-described embodiment. For example, in each of the ejection heads 11 and 12, the number of the nozzle arrays 21A and 21B is not limited to two, and may be an arbitrary number of one or more. Further, 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 the discharge heads 11 and 12 in the head unit 10 and the arrangement configuration thereof can be appropriately changed. Further, as a driving method of the ejection 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 material discharge device)
Next, the electrical configuration and operation of the liquid material discharge apparatus will be described with reference to FIGS.
FIG. 4 is a diagram showing an electrical configuration of the liquid material discharge apparatus related to driving of the discharge head. FIG. 5 is a diagram illustrating the configuration of the switching circuit and the drive signal selection circuit in the ejection head. FIG. 6 is a timing diagram of drive signals and control signals.

  As shown in FIG. 4, the ejection head 11 (12) includes a plurality of piezoelectric elements 16, a switching circuit 17, a drive signal selection circuit 18, and four input systems COM1 to COM4. The plurality of piezoelectric elements 16 are provided so that one piezoelectric element 16 corresponds to one nozzle n. As shown in FIG. 5, the switching circuit 17 includes a plurality of switching elements 17E. Each of the plurality of switching elements 17E corresponds to one piezoelectric element 16, and each switching element 17E includes a transmission gate in which a P-channel FET (Field Effect Transistor) and an N-channel FET are combined. .

  The drive signal selection circuit 18 includes a plurality of drive signal selection units 18E in which the four transmission gates TG1 to TG4 are used as a set of drive signal selection units 18E. In the plurality of drive signal selectors 18E, one set of drive signal selectors 18E is provided corresponding to one switching element 17E. Each drive signal selector 18E outputs a drive signal COM input via any one of four input systems COM1 to COM4 described later to the corresponding switching element 17E of the switching circuit 17.

  The input systems COM1 to COM4 are connected to the drive signal selection circuit 18, and can receive four drive signals COM of different types in parallel. The drive signal COM received by the input systems COM1 to COM4 is supplied to the drive signal selection circuit 18. The four transmission gates TG1 to TG4 constituting one set of drive signal selection unit 18E are connected to any one of the input systems COM1 to COM4 without overlapping each other. In the present embodiment, the four transmission gates TG1 to TG4 have TG1 connected to the input system COM1, TG2 connected to the input system COM2, TG3 connected to the input system COM3, and TG4 connected to the input system COM4. Yes. The ejection head 11 (12) is electrically connected to the control circuit board 30.

  The control circuit board 30 includes DACs (Digital Analog Converters) 31 </ b> A to 31 </ b> D, a waveform data selection circuit 32, and a data memory 33. Each of the DACs 31A to 31D receives the input of the waveform data WD1 to WD4 and generates a drive signal COM corresponding to the waveform data WD1 to WD4. The waveform data selection circuit 32 has a storage memory (not shown) in which the waveform data WD1 to WD4 are stored. The data memory 33 stores discharge control data input from the outside. In the input systems COM1 to COM4 of the ejection head 11 (12), COM1 is connected to the DAC 31A, COM2 is connected to the DAC 31B, COM3 is connected to the DAC 31C, and COM4 is connected to the DAC 31D.

  One electrode 16c of each piezoelectric element 16 is connected to the ground lines (GND) of the DACs 31A to 31D. The other electrode (hereinafter referred to as segment electrode 16s) of each piezoelectric element 16 is connected to each switching element (not shown) of the switching circuit 17. A clock signal CLK and a latch signal LAT corresponding to each ejection timing are input to the switching circuit 17, the drive signal selection circuit 18, and the waveform data selection circuit 32.

The data memory 33 stores ejection data SIA, drive signal selection data SIB, and waveform number data WN for each ejection timing that is periodically set according to the scanning position of the ejection head 11 (12). .
The ejection data SIA is data defining switching between supply and non-supply of the drive signal COM to each piezoelectric element 16 (ON state and OFF state). The ejection data SIA is composed of 1 bit (0, 1) per piezoelectric element 16, that is, per switching element.

  The drive signal selection data SIB is data defining the input systems COM1 to COM4 corresponding to each piezoelectric element 16. That is, the drive signal selection data SIB is data instructing that one of the four input systems COM1 to COM4 should be selected. This drive signal selection data SIB is composed of 4 bits per one piezoelectric element 16, that is, one set of drive signal selection section 18E.

  Here, the drive signal selection data SIB is data defining switching between the ON state and the OFF state for each of the four transmission gates TG1 to TG4 constituting the set of drive signal selection unit 18E. In one set of drive signal selectors 18E, if only one of the four transmission gates TG1 to TG4 is turned on and the other three are turned off, one set of drive signal selectors The function as 18E is fulfilled. Therefore, the data composed of 4 bits per set of the drive signal selection unit 18E can take any one of 1, 2, 4, and 8 in decimal.

  The waveform number data WN is data defining the types of the waveform data WD1 to WD4 input to the DACs 31A to 31D, and is composed of 7 bits (0 to 127) for the DACs 31A to 31D. 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, in the period of timings t1 to t2 shown in FIG. 6, the ejection data SIA, the drive signal selection data SIB, and the waveform number data WN are converted into serial signals, respectively, and the switching circuit 17, the drive signal selection circuit 18, and the waveform data selection. It is transmitted to the circuit 32. At timing t2, when each data is latched based on the latch signal LAT, the segment electrode 16s of each piezoelectric element 16 instructed to be ejected by the ejection data SIA (defined in the ON state) It is connected to each of the input systems COM1 to COM4 specified by the selection data SIB.

  Here, when the value of the drive signal selection data SIB input to one set of drive signal selection units 18E in the drive signal selection circuit 18 is “1”, this one set of drive signal selection units 18E corresponds. The segment electrode 16s of the piezoelectric element 16 is connected to the input system COM1. Similarly, when the value of the drive signal selection data SIB is “2”, the segment electrode 16s is connected to the input system COM2, and when the value of the drive signal selection data SIB is “4”, the segment electrode 16s is connected to the input system COM3. When the value of the drive signal selection data SIB is “8”, the segment electrode 16s is connected to the input system COM4.

When the waveform number data WN is latched at the timing t2, the waveform data selection circuit 32 sets the waveform data WD1 to WD4 to be output to the DACs 31A to 31D.
In each period of timing t3 to t4, t4 to t5, and t5 to t6, the drive signal COM is generated in a series of steps of increasing potential, maintaining potential, and decreasing potential based on the waveform data WD1 to WD4 set at timing t2. Generated by each DAC 31A-31D. The drive signals COM generated by the DACs 31A to 31D are supplied to the piezoelectric elements 16 that are connected to the input systems COM1 to COM4. Thereby, the volume (pressure) control of each cavity communicating with each nozzle n is performed. The potential increasing component at the timings t3 to t4 expands the cavity and plays a role of drawing the liquid material inward of the nozzle n. Further, the potential drop component at the timings t5 to t6 plays a role of contracting the cavity and pushing the liquid material out of the nozzle n 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 closely depend on the discharge amount of the liquid material 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. Note that the drive signal COM to be generated is not limited to a simple trapezoidal wave as shown in this embodiment, and various known waveforms can be appropriately employed. 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. In this embodiment, by inputting different types of waveform data WD1 to WD4 to the DACs 31A to 31D, it is possible to output drive signals COM of different drive voltages Vh to the input systems COM1 to COM4. is there. 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, this corresponds to the drive voltage Vh in increments of 0.1V.

  By the way, in the ejection head 11 (12), the ejection amount from each nozzle n may vary in each nozzle array 21A, 21B. In the liquid material ejection device 200 according to the present embodiment, by allocating any one of a plurality of types of drive signals COM to each of the plurality of piezoelectric elements 16, variation in the ejection amount in each nozzle array 21 </ b> A, 21 </ b> B is achieved. Can be reduced.

  In the present embodiment, the plurality of piezoelectric elements 16 are classified into four groups for each of the nozzle arrays 21A and 21B, and different types of drive signals COM are assigned in units of groups. Group classification in the plurality of piezoelectric elements 16 can be achieved by setting the drive signal selection data SIB. That is, each of the plurality of piezoelectric elements 16 is associated with one of the four input systems COM1 to COM4 by the drive signal selection data SIB. When the plurality of piezoelectric elements 16 are classified into four groups, each of the plurality of nozzles n corresponds to the group classification of each piezoelectric element 16 because each piezoelectric element 16 and each nozzle n correspond one-to-one. Into four groups.

(Drive signal setting method)
Here, with reference to FIG. 4, FIG. 7, FIG. 8, and FIG. 9, a method for setting an appropriate condition (drive voltage Vh) of the drive signal COM to each piezoelectric element 16 will be described.
FIG. 7 is a block diagram showing an apparatus configuration for setting a drive signal. FIG. 8 is a flowchart showing a flow of processing for setting a drive signal. FIG. 9 is a diagram illustrating an example of the distribution of discharge amount and group classification for each nozzle n.

As shown in FIG. 7, the setting device 300 for setting the drive signal includes a liquid material supply device 301, a control circuit board 302, a liquid material receiving container 303, a weight measuring device 304, and a liquid material receiving substrate. 305, a substrate moving device 306, a volume measuring device 307, and a PC (Personal Computer) 308.
The liquid material supply device 301 supplies a liquid material to the ejection head 11 (12). The control circuit board 302 is for driving the ejection head 11 (12). The liquid material receiving container 303 receives the liquid droplets discharged from the discharge head 11 (12) and stores the received liquid droplets as a liquid material. The weight measuring device 304 measures the weight of the liquid material receiving container 303. The liquid material receiving substrate 305 receives droplets ejected from the ejection head 11 (12). The substrate moving device 306 moves the liquid material receiving substrate 305 in the substrate surface direction. The volume measuring device 307 is disposed on the liquid material receiving substrate 305 and measures the volume of the droplet received by the liquid material receiving substrate 305. The PC 308 controls the driving of the ejection head 11 (12) via the control circuit board 302, controls the driving of the substrate moving device 306, controls the weighing operation of the weight measuring device 304 and the volume measuring device 307, and the measurement result. Calculate based on

  The control circuit board 302 has the same configuration as the control circuit board 30 (see FIG. 4). Further, the liquid material receiving container 303 may be any material as long as it is not eroded by the liquid material. However, the liquid material receiving container 303 is configured to suppress the volatilization of the liquid material by disposing a porous member such as a sponge in the opening. It is preferable. 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 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 arrays 21A and 21B at high speed and with high accuracy, and the volume measuring device 307 measures the discharge amount of each nozzle n. Suitable for

  In setting the drive signal COM, in a state where the discharge head 11 (12) is attached to the setting device 300, first, the average discharge amount of all the nozzles n (excluding dummy nozzles) in each nozzle array 21A, 21B is measured. (Step S1 in FIG. 8). Specifically, ejection is performed a number of times (for example, 100,000 times) for each nozzle n, 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 measured drive voltage Vh and the average discharge amount is linearly complemented to calculate the reference drive voltage Vs for obtaining the average discharge amount of the reference discharge amount (design value according to the specification) ( Step S2 in FIG. Further, the rate of change 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. 8).

  Next, the drive signal COM of the drive voltage Vh = Vs is supplied to all the piezoelectric elements 16 of the nozzle arrays 21A and 21B, and droplets are ejected to the liquid material receiving substrate 305, and the ejection amount is measured ( Step S4 in FIG. Since the surface of the liquid material receiving substrate 305 has been subjected to a liquid repellent treatment, the liquid droplets discharged from each nozzle n form independent hemispherical liquid droplets on the liquid material receiving substrate 305. The three-dimensional shape of the droplet is measured by the volume measuring device 307, and the measurement data is analyzed by the PC 308, whereby the discharge amount is obtained. Since the discharge amount per one time of each nozzle n is extremely small, the discharge of each nozzle n is performed at the same location on the liquid material receiving substrate 305 in order to increase the accuracy of the volume measurement (discharge amount measurement) of the droplets. It is repeated a plurality of times (for example, three times).

  The discharge amount of each nozzle n measured in step S4 is shown as a spatial distribution in the arrangement direction of the nozzle arrays 21A and 21B as shown in FIG. 9 (the discharge amount is expressed as a relative ratio with respect to the reference discharge amount q0). ing). As shown in FIG. 9, in the present embodiment, the discharge amount tends to be relatively large near the ends of the nozzle arrays 21A and 21B, and the discharge amount tends to be relatively small near the center of the nozzle arrays 21A and 21B. is there.

  Next, group setting for each nozzle n is performed based on the measurement in step S4 (step S5 in FIG. 8). 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, the input systems COM1 to COM4 are associated with the groups A to D (step S6 in FIG. 8). At this time, each piezoelectric element 16 belonging to the group A is associated with the input system COM1. Each piezoelectric element 16 belonging to the group B is associated with the input system COM2. Each piezoelectric element 16 belonging to the group C is associated with the input system COM3. Each piezoelectric element 16 belonging to the group D is associated with the input system COM4.

  Next, an appropriate drive voltage Vh (hereinafter, referred to as appropriate drive voltages VhA, VhB, VhC, VhD) corresponding to the groups A to D is calculated (step S7 in FIG. 8). The “proper” condition can be freely defined, but in the present embodiment, the appropriate drive voltages VhA to VhD for making the statistical values of the discharge amounts related to the groups A to D coincide with the reference discharge amount q0, respectively. Is calculated based on the measured value of the ejection amount in step S4, the correlation coefficient α, and the reference drive voltage Vs.

  Here, the statistical values of the discharge amounts related to the groups A to D indicate numerical values obtained from the statistics of the discharge amounts of the plurality of nozzles n belonging to the groups A to D. In this embodiment, The average discharge amount of nozzles n belonging to groups A to D is used. Thereby, the liquid material which becomes an appropriate amount (reference discharge amount q0) on an average basis in groups A to D from the nozzles n of groups A to D, respectively, is discharged from the plurality of nozzles n. In addition, you may make it perform step S7 by making the median value of the discharge amount of the nozzle n which belongs to each group AD into the statistical value of the discharge amount which concerns on each group AD.

  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 by the relative ratio, for example, when a situation occurs in which the viscosity of the liquid material changes and the discharge amount changes uniformly, the entire nozzle arrays 21A and 21B There is an advantage that it is only necessary to measure the average discharge amount and reset the reference drive voltage Vs.

  Next, one of the appropriate drive voltages VhA, VhB, VhC, and VhD is selected and set for each nozzle n as the drive voltage Vh associated with each nozzle n (step S8 in FIG. 8). In the drive control, if the appropriate drive voltage VhA is associated with the DAC 31A, the appropriate drive voltage VhB is associated with the DAC 31B, the appropriate drive voltage VhC is associated with the DAC 31C, and the appropriate drive voltage VhD is associated with the DAC 31D, each group. Drive signals COM under appropriate conditions can be assigned to A to D. In the following, the drive signal COM at the appropriate drive voltage VhA assigned to the group A is denoted as drive signal COM (A). The drive signal COM at the appropriate drive voltage VhB assigned to the group B is denoted as drive signal COM (B). The drive signal COM at the appropriate drive voltage VhC assigned to the group C is denoted as drive signal COM (C). The drive signal COM at the appropriate drive voltage VhD assigned to the group D is denoted as drive signal COM (D).

  Here, the number of nozzles n constituting each group A to D is not limited to the above-described aspect. However, since the drive voltage Vh is set in units of groups, by making the number of nozzles n constituting each group A to D substantially equal, each drive voltage Vh, that is, each input system COM1 to COM4, is set. An imbalance in the number of corresponding piezoelectric elements 16 can be made difficult to occur. Since the corresponding number of the piezoelectric elements 16 in the input systems COM1 to COM4 affects the distortion of the drive signal and the like, it is preferable that an imbalance between the input systems COM1 to COM4 does not occur as much as possible.

(Test discharge method)
With reference to FIG. 1, FIG. 4, and FIG. 10, a method of performing test discharge with the discharge head 11 (12) in which the appropriate drive voltages VhA, VhB, VhC, and VhD for each piezoelectric element 16 are set will be described. To do.
FIG. 10 is a flowchart showing the flow of the test ejection process.

In this test ejection, the head unit 10 in which the appropriate drive voltages VhA, VhB, VhC, and VhD for the piezoelectric elements 16 are set for each ejection head 11 (12) is attached to the liquid material ejection device 200 shown in FIG. It is done in the state.
Further, this test discharge is performed on a test discharge medium placed on the stage 205 of the liquid material discharge apparatus 200. In the present embodiment, a test sheet is employed as a test medium.

The test discharge process shown in FIG. 10 is started when discharge control data for test discharge is input to the data memory 33 shown in FIG. At this time, one of the plurality of ejection heads 11 (12) in the head unit 10 is set as a test ejection target by the ejection control data. In the following, the ejection head 11 (12) that is the target of the test ejection is referred to as a test target head.
In the test ejection process, first, the movement along the main scanning direction of the main scanning moving table 203 is started in a state where the nozzle arrays 21A and 21B of the respective ejection heads 11 (12) are opposed to the test paper (FIG. 10). Step S31).

Next, one of the nozzle arrays 21A and 21B in the test target head is determined as an ejection target array, and droplets are ejected from the ejection target array a plurality of times at predetermined intervals (step S32 in FIG. 10). Here, the predetermined interval can be defined by a period, a moving amount of the main scanning moving table 203, or the like. For example, droplets can be ejected at a predetermined cycle based on the clock signal CLK shown in FIG. 4, or droplets can be ejected for each predetermined movement amount of the main scanning moving table 203.
In the present embodiment, test discharge is performed by discharging droplets for each predetermined movement amount of the main scanning moving table 203.

  In step S32 in FIG. 10, one of the groups A to D (for example, group D) in the ejection target array is set as a target group that is a target for ejecting droplets. The piezoelectric element 16 belonging to the target group is supplied with a drive signal COM (appropriate drive voltage VhD) with an appropriate condition assigned to the target group. On the other hand, each piezoelectric element 16 belonging to the remaining groups (groups A to C) is supplied with a drive signal COM of a type that suppresses the ejection of droplets. Examples of the drive signal COM that suppresses the discharge of the droplet include a drive signal COM that slightly vibrates the piezoelectric element 16 to the extent that the droplet does not discharge from the nozzle n.

  Such drive control is performed based on the discharge control data. At this time, the discharge data SIA included in the discharge control data is data for turning on all the switching elements 17E (except those corresponding to the dummy nozzles). Further, the drive signal selection data SIB is data that defines combinations of the groups A to D and the input systems COM1 to COM4 that are associated in step S6 of FIG.

  The waveform number data WN includes data for instructing the DACs 31A to 31D corresponding to the target group to generate the driving signal COM under appropriate conditions, and a driving signal of a type that suppresses the ejection of droplets to the other DACs 31A to 31D. Data for instructing generation of COM. For example, when the group D is set as the target group, the DAC 31D corresponds to the target group. Therefore, in this case, the waveform number data WN is data that instructs the DAC 31D to generate the drive signal COM (D) at the appropriate drive voltage VhD, and the type of drive that suppresses droplet ejection for the DACs 31A to 31C. Data for instructing generation of the signal COM.

Next, it is determined whether or not the ejection of droplets in all the groups A to D has been completed (step S33 in FIG. 10). At this time, if it is determined that the process has not been completed (NO), the target group setting is changed in step S34, and then the process proceeds to step S32. If it is determined that the process has been completed (YES), the process proceeds to step S35. To do.
In step S34, the groups A to D set as the target group are changed to other groups A to D. For example, when group D is set as the target group, one of groups A to C is set as a new target group. And the process of step S32 is implemented with respect to a new object group. That is, the process of step S32 is performed over all of the groups A to D while changing the groups A to D as the target group.

Next, it is determined whether or not the ejection of droplets from all the nozzle arrays 21A and 21B in the test target head has been completed (step S35 in FIG. 10). At this time, if it is determined that the process is not completed (NO), the setting of the ejection target array is changed in step S36, and then the process proceeds to step S32. If it is determined that the process is completed (YES), the process proceeds to step S37. Transition.
Next, it is determined whether or not the ejection of droplets from all the ejection heads 11 (12) in the head unit 10 has been completed (step S37 in FIG. 10). At this time, if it is determined that the process is not completed (NO), the setting of the test target head is changed in step S38, and then the process proceeds to step S32. If it is determined that the process is completed (YES), the test ejection process is performed. Exit.

(Test discharge pattern)
With reference to FIG. 11 and FIG. 12, a test ejection pattern as a result of performing test ejection on a test medium will be described.
FIG. 11 is a diagram illustrating an example of a test ejection pattern. In FIG. 11, one nozzle array 21A (21B) and a test ejection result 401 expressed on the test medium M by droplets ejected from the nozzle array 21A (21B) are shown together. Here, the test ejection pattern 400 refers to the medium on which the test ejection result 401 appears.
FIG. 12 is a diagram illustrating another example of the test ejection pattern.
In FIG. 11 and FIG. 12, the test ejection result 401 is represented by filled dots.

  In the test ejection pattern 400 shown in FIG. 11, the drive signals COM (A) to COM (D) are located at different positions for the drive signals COM (A) to COM (D) assigned to the groups A to D. The test discharge result 401 is displayed. The test discharge result 401 for each of the drive signals COM (A) to COM (D) is shifted along the main scanning direction, which is a direction intersecting with the arrangement direction of the nozzle array 21A (21B). According to this test ejection pattern 400, the test ejection results 401 for each of the groups A to D are arranged in a direction intersecting with the arrangement direction of the nozzle array 21A (21B). It is possible to easily grasp the correspondence between 401 and each nozzle n.

A scale 411 indicating the positioning of each nozzle n in the nozzle array 21A (21B) is attached to the test ejection pattern 410 shown in FIG. In the example shown in FIG. 12, scales 411 are attached at intervals corresponding to every fifth nozzle n. Such a test ejection pattern 410 has a scale 411 drawn on the test medium M by the ejection head 11 (12) before the test ejection process shown in FIG. 10, or the test medium M on which the scale 411 has been printed in advance. Or the like can be formed.
According to this test ejection pattern 410, it is possible to easily count the nozzle numbers using the scale 411 as a clue, so that it is easier to grasp the correspondence between the test ejection results 401 of each group A to D and each nozzle n. be able to.

  In this embodiment, groups A to D correspond to a plurality of sets, nozzle array 21A (21B) corresponds to a column, scale 411 corresponds to a mark, and drive signal selection data SIB corresponds to input selection data. Then, the switching element 17E corresponds to the switch unit, the process of step S32 corresponds to step (a), and the scale 411 is drawn on the test medium M by the ejection head 11 (12) corresponds to step (b). is doing.

  In the present embodiment, for each nozzle array 21A, 21B, the plurality of piezoelectric elements 16 constituting each nozzle array 21A, 21B are classified into four groups A to D. The plurality of piezoelectric elements 16 are assigned drive signals COM of different types in groups A to D. The ejection head 11 (12) has four input systems COM1 to COM4 for each of the nozzle arrays 21A and 21B. Each group A to D is associated with each input system COM1 to COM4. The input systems COM1 to COM4 can receive four drive signals COM of different types in parallel by the input systems COM1 to COM4 receiving one drive signal COM. That is, in the present embodiment, four drive signals COM of different types can be supplied in parallel to each of the four groups A to D. Thereby, the variation in the discharge amount from the plurality of nozzles n in one nozzle array 21A (21B) can be reduced.

  In the present embodiment, it is possible to grasp whether or not the drive signals COM (A) to COM (D) are assigned to the groups A to D from the test ejection results. The test ejection process shown in FIG. 10 includes step S32. In this step S32, one of the groups A to D of the ejection target array is set as a target group, and the drive signals COM (A) to COM (D) assigned to the target group correspond to the piezoelectric elements belonging to the target group. It is supplied to the element 16. Further, the remaining piezoelectric elements 16 are supplied with a drive signal COM that suppresses the ejection of droplets.

  According to step S32, the drive signal COM is supplied to each of the plurality of piezoelectric elements 16 in the ejection target array. At this time, if the drive signals COM (A) to COM (D) to be supplied to the piezoelectric elements 16 belonging to the target group are appropriately assigned, droplets are ejected from the nozzles n belonging to the target group, No droplets are ejected from the remaining nozzles n. As a result, it is possible to determine whether or not the drive signals COM (A) to COM (D) are appropriately assigned to the target group.

  In this test ejection process, step S32 is performed over all of the groups A to D while changing the groups A to D as the target group. Therefore, the test ejection results 401 for the groups A to D are displayed on the test medium M. That is, from this test medium M, it is possible to grasp whether or not the drive signals COM (A) to COM (D) are assigned to all the groups A to D. Therefore, in this test ejection process, it is possible to easily confirm the types of the drive signals COM (A) to COM (D) assigned to each of the plurality of piezoelectric elements 16. It can be easily confirmed whether or not appropriate drive signals COM (A) to COM (D) are supplied.

  In this test ejection process, step S32 is performed while changing the relative position between the ejection head 11 (12) and the test medium M. Therefore, the test ejection for each of the groups A to D is performed on the test medium M. The result 401 appears at a different position. This makes it easier to confirm the types of drive signals COM (A) to COM (D) assigned to each of the plurality of piezoelectric elements 16.

  In this test ejection process, the relative position between the ejection head 11 (12) and the test medium M is changed in the main scanning direction that intersects the arrangement direction of the nozzle arrays 21A (21B). The test discharge results 401 for the groups A to D are displayed side by side in the main scanning direction. Thereby, it is possible to easily grasp the correspondence relationship between the test discharge result 401 and each of the plurality of nozzles n.

  In the present embodiment, for one nozzle array 21A (21B), a case where a plurality of nozzles n constituting the nozzle array 21A (21B) are classified into four groups A to D has been described as an example. The number of groups to be performed is not limited to this, and an arbitrary number of 2 or more can be adopted. In this case, the numbers of the DACs 31A to 31D, the input systems COM1 to COM4, and the drive signal selection unit 18E are set according to the number of groups.

  In the present embodiment, the case where the scale 411 is provided at intervals corresponding to every fifth nozzle n in the test ejection pattern 410 has been described as an example. However, the interval between the scales 411 is not limited to this, and the nozzle An interval corresponding to an arbitrary number of n can be set.

Further, the scale 411 is not limited to the case where the scale 411 is provided over the range exceeding the test discharge results 401 of the groups A to D in the main scanning direction, and one within or outside the range of the test discharge results 401 of the groups A to D. The case where it is attached to a part or all is allowed.
In the present embodiment, the scale 411 has been described as an example of the mark indicating the positioning of each nozzle n. However, the mark is not limited to this, and an arbitrary mark may be employed.

In addition, the present embodiment is not limited to application to the liquid material discharge apparatus 200, and can also be applied to an ink jet printer.
In the present embodiment, the case where the liquid material ejection device 200 is used for forming a color filter of the display panel has been described as an example. However, the application of the liquid material ejection device 200 is not limited thereto.
The liquid material discharge device 200 can be applied to, for example, formation of a fluorescent film in a plasma display device, formation of an element film in an organic EL device, formation of a conductive wiring or a resistance element in an electric circuit, and the like.

The perspective view which shows the principal part structure of a liquid discharger. FIG. 5 is a bottom view showing an arrangement configuration of ejection heads in a head unit. The top view which shows the relationship between the scanning locus | trajectory of a nozzle, and a discharge target object. The figure which shows the electrical constitution of the liquid discharge apparatus which concerns on the drive of a discharge head. 3A and 3B illustrate a configuration of a switching circuit and a drive signal selection circuit in an ejection head. The timing diagram of a drive signal and a control signal. The block diagram which shows the apparatus structure for performing the setting of a drive signal. The flowchart which shows the flow of the process for a drive signal setting. The figure which shows an example of distribution and the group classification | category of the discharge amount for every nozzle. The flowchart which shows the flow of a test discharge process. The figure which shows an example of a test discharge pattern. The figure which shows the other example of a test discharge pattern.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11, 12 ... Discharge head, 16 ... Piezoelectric element, 17 ... Switching circuit, 17E ... Switching element, 18 ... Drive signal selection circuit, 18E ... Drive signal selection part, 21A, 21B ... Nozzle array, 30 ... Control circuit board, 31A 31D ... DAC, 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 ... PC, 400,410 ... Test ejection pattern, 401 ... Test ejection result, 411 ... Scale, M ... Test medium, n ... Nozzle, COM1-COM4 ... Input system .

Claims (8)

Discharge having a plurality of nozzles that discharge a liquid material as droplets and a plurality of drive elements that are provided corresponding to each of the plurality of nozzles and that discharge the droplets from the nozzles upon receiving a drive signal A test ejection method for performing test ejection on a medium with a head,
The ejection head is divided into a plurality of sets in which the plurality of nozzles and the plurality of driving elements are paired with the nozzles and the driving elements corresponding to the nozzles. The drive signals of different types are assigned to the plurality of drive elements in the set unit,
One of the plurality of groups is set as a target group for which the droplet is to be ejected, and the drive signal assigned to the target group is sent to each of the drive elements belonging to the target group. Step (a) of supplying the drive signal of a type that suppresses ejection of the droplets to each of the drive elements belonging to the remaining set, while changing the set as the target set, A test discharge method, which is performed over all of the plurality of sets.   The test ejection method according to claim 1, wherein the step (a) is performed over all of the plurality of sets while changing a relative position between the ejection head and the medium. The plurality of nozzles constitute a row,
The test ejection method according to claim 2, wherein the relative position is changed in a direction intersecting with the direction of the row.   The test ejection method according to claim 3, further comprising a step (b) of marking on the medium a mark indicating the positioning of each nozzle in the row. The ejection head has a plurality of input systems that can receive a plurality of different types of drive signals in parallel, and
The drive input from the selected input system based on input selection data provided corresponding to each of the drive elements and instructing that one of the plurality of input systems should be selected A drive signal selector for outputting a signal;
The drive signal is provided corresponding to each of the drive elements, the drive signal is input from the drive signal selection unit, and the drive signal is converted to the drive element based on ejection data that permits output of the drive signal to the drive element. A switch unit that outputs to
The plurality of drive elements are divided into the plurality of sets by associating each of the drive elements with any one of the plurality of input systems in the input selection data,
In the step (a), the drive signal assigned to the target set is input to the input system corresponding to the target set, and the droplets are input to the input systems corresponding to the remaining sets. Input the drive signal of the kind that suppresses the discharge of
5. The test ejection method according to claim 1, wherein the ejection data permitting the output of each drive signal to each drive element is input to each switch unit. 6. Discharge having a plurality of nozzles that discharge a liquid material as droplets and a plurality of drive elements that are provided corresponding to each of the plurality of nozzles and that discharge the droplets from the nozzles upon receiving a drive signal It is a test discharge pattern in which the discharge result of performing test discharge on the medium with the head is expressed,
The ejection head is divided into a plurality of sets in which the plurality of nozzles and the plurality of driving elements are paired with the nozzles and the driving elements corresponding to the nozzles. The drive signals of different types are assigned to the plurality of drive elements in the set unit,
The test discharge pattern, wherein the discharge result for each set is displayed on the medium at a different position for each set. The plurality of nozzles constitute a row,
The test ejection pattern according to claim 6, wherein the ejection result for each group is exposed to the medium in a state in which the ejection result is arranged in a direction intersecting the direction of the row for each group.   The test ejection pattern according to claim 7, wherein a mark indicating the positioning of each nozzle in the row is written on the medium.

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