JP2011101870A - Method for obtaining ejection amount from droplet ejection head, method for determining appropriate voltage, and droplet ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for obtaining the ejection amount from a droplet ejection head, a method for determining appropriate voltage, and a droplet ejection device which accurately obtains the ejection amount or determines appropriate drive voltage according to a change in ejection rate corresponding to the number of nozzles simultaneously driven. <P>SOLUTION: The method for obtaining the ejection amount from a droplet ejection head includes an ejection step of simultaneously driving one or more ejection nozzles 21 by the standard drive voltage from a head driver, an ejection amount measuring step of measuring the ejection amounts ejected from the one or more ejection nozzles 21 in the ejection step, an ejection amount correcting step of correcting the measured ejection amounts from the one or more ejection nozzles 21 using correction values according to the number of ejection nozzles 21 simultaneously driven in the ejection step, and an ejection amount obtaining step of obtaining the corrected ejection amounts from the one or more ejection nozzles 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge head discharge amount acquisition method, an appropriate voltage determination method, and a droplet discharge device for a droplet discharge head having one or more discharge nozzles driven by one head driver. .

  Conventionally, as a method for obtaining the discharge amount of this type of droplet discharge head, a discharge step of discharging droplets from one or more discharge nozzles of a plurality of discharge nozzles, and each discharge amount of one or more discharged discharge nozzles are performed. There is known a measuring step for measuring and a supplementing step for complementing each discharge amount of the remaining discharge nozzles based on the measured discharge amounts of one or more discharge nozzles (see Patent Document 1). ).

JP 2009-151219 A

  By the way, in the discharge amount acquisition method as described above, one or more discharge nozzles are driven at the same time in the discharge step, but the discharge amount of each discharge nozzle changes according to the number of simultaneously driven discharge nozzles. . Strictly speaking, if the number of simultaneous drives changes, the electrical load applied to the head driver will fluctuate, so the drive waveform from the head driver will be distorted, and as a result, the discharge amount from each discharge nozzle will change. A phenomenon occurs. Therefore, even if each discharge nozzle is driven by a common drive voltage from the head driver, each discharge amount varies depending on the number of simultaneous drive, and there is a problem that each discharge amount with respect to the drive voltage is not constant. As a result, there is a problem that it is not possible to accurately obtain the ejection amount with respect to the standard drive voltage and to determine the appropriate drive voltage.

  The present invention relates to a method for acquiring a discharge amount of a droplet discharge head, a method for determining an appropriate voltage, and a method for determining an appropriate drive voltage that can accurately acquire a discharge amount and determine an appropriate drive voltage in accordance with a change in the discharge amount according to the number of simultaneously driven elements. It is an object to provide a droplet discharge device.

  The method for obtaining a discharge amount of a droplet discharge head according to the present invention targets a droplet discharge head having one or more discharge nozzles driven by one head driver, and each discharge amount of one or more discharge nozzles with respect to a standard drive voltage. A method for acquiring a discharge amount of a droplet discharge head for acquiring a discharge step of simultaneously driving one or more discharge nozzles by a standard drive voltage from a head driver, and a method for acquiring one or more discharge nozzles discharged by the discharge step A discharge amount measuring step for measuring each discharge amount, and a discharge amount correction step for correcting each measured discharge amount of one or more discharge nozzles with a correction value corresponding to the number of simultaneously driven discharge nozzles driven simultaneously in the discharge step. And a discharge amount acquisition step of acquiring each discharge amount of the corrected one or more discharge nozzles.

  The method for obtaining a discharge amount of a droplet discharge head according to the present invention targets a droplet discharge head having a plurality of discharge nozzles driven by two or more head drivers, and sets each discharge amount of the plurality of discharge nozzles relative to a standard drive voltage. A method for acquiring a discharge amount of a droplet discharge head to be acquired, wherein a plurality of discharge nozzles are assigned as one or more discharge nozzles driven by each head driver, and the discharge amount of the droplet discharge head is acquired. And a total discharge amount acquisition step of acquiring each discharge amount of one or more discharge nozzles driven by two or more head drivers obtained by the method and acquiring each discharge amount as a plurality of discharge nozzles. And

  According to these configurations, the measured discharge amount is corrected and acquired by the correction value according to the simultaneous drive number in the discharge process (during inspection discharge), thereby canceling the discharge amount change according to the simultaneous drive number. be able to. Therefore, it is possible to cope with the change in the discharge amount, and the discharge amount can be obtained with high accuracy.

  The method for determining an appropriate voltage of a droplet discharge head according to the present invention includes one or more discharges driven by each head driver based on the discharge amounts of a plurality of discharge nozzles acquired by the discharge amount acquisition method of the droplet discharge head. Based on the average discharge amount calculation step for calculating the average discharge amount of the nozzles of the nozzles and the calculated average discharge amount and standard drive voltage for each head driver, the appropriate voltage for calculating the appropriate drive voltage for the appropriate discharge amount for each head driver The calculation process and the appropriate voltage correction process for correcting the appropriate driving voltage calculated for each head driver by the correction value according to the simultaneous driving number of ejection nozzles that are simultaneously driven in the drawing process, and the correctness for each corrected head driver And an appropriate voltage determining step for determining an appropriate drive voltage for the plurality of ejection nozzles.

  Another method for determining an appropriate voltage for a droplet discharge head according to the present invention is directed to a droplet discharge head having one or more discharge nozzles driven by one head driver, and determines an appropriate drive voltage for one or more discharge nozzles. A method for determining an appropriate voltage for a droplet discharge head to perform, an appropriate voltage calculation step for calculating an appropriate drive voltage for an appropriate discharge amount based on an average discharge amount of one or more discharge nozzles with respect to a standard drive voltage, and a calculated appropriate An appropriate voltage correction process for correcting the drive voltage with a correction value corresponding to the number of simultaneously driven ejection nozzles that are simultaneously driven in the drawing process, and the corrected appropriate drive voltage is determined as an appropriate drive voltage for one or more ejection nozzles. And an appropriate voltage determining step.

  According to these configurations, by correcting the calculated appropriate driving voltage with a correction value corresponding to the number of simultaneous drivings during the drawing process, it is possible to cancel the discharge amount change according to the number of simultaneous drivings on the driving voltage side. it can. Therefore, it is possible to cope with the change in the discharge amount, and to determine the appropriate drive voltage with high accuracy.

  A droplet discharge device of the present invention is a droplet discharge device that performs drawing processing on a workpiece by driving the droplet discharge head while moving the droplet discharge head relative to the workpiece. The driving of the droplet discharge head is controlled based on the appropriate drive voltage determined by the method for determining the appropriate voltage of the droplet discharge head.

  According to this configuration, the drawing process for the workpiece can be performed with high accuracy by determining the appropriate driving voltage of the droplet discharge head using the appropriate voltage determining method capable of determining the appropriate driving voltage with high accuracy. it can.

It is a front and back external perspective view of a droplet discharge head. It is sectional drawing of a droplet discharge head. It is a partial exploded perspective view of a pump part. It is the top view which showed typically the discharge inspection apparatus. It is a block diagram of the main control system of a discharge inspection apparatus. It is the flowchart which showed the discharge test | inspection operation | movement and appropriate voltage determination operation | movement in a discharge test | inspection apparatus. It is the figure which showed the correspondence data (a) of the simultaneous drive number and the 1st drive number correction value, and the correspondence data (b) of the simultaneous drive number and the 2nd drive number correction value. It is the perspective view which showed the droplet discharge apparatus typically.

  Hereinafter, a discharge inspection apparatus for a droplet discharge head to which a discharge amount acquisition method for a droplet discharge head according to an embodiment of the present invention is applied will be described with reference to the accompanying drawings. This discharge inspection device performs a single inspection of a droplet discharge head before being mounted on a droplet discharge device to be described later, including a discharge inspection for determining the presence or absence of discharge for one droplet discharge head, Carry out flight inspection, flight speed, and discharge rate measurement. In addition, droplets are ejected from the droplet ejection head onto the inspection sheet to form a plurality of landing dots, and each landing dot is imaged to measure the ejection amount of each ejection nozzle. First, prior to the description of the discharge inspection apparatus, a droplet discharge head to be inspected will be described.

  As shown in FIGS. 1 to 3, the droplet discharge head 1 is a so-called double inkjet head (inkjet droplet discharge head 1) adopting a so-called piezo method, and has two connection needles 5. A functional liquid introduction unit 2, two head substrates 3 connected to the functional liquid introduction unit 2, and a head body 4 that discharges the functional liquid below the head substrate 3 are provided (see FIG. 1A). ).

  The functional liquid introduction unit 2 has a pair of connecting needles 5 and is supplied with a functional liquid from a functional liquid supply unit 56 (see FIG. 4) via a piping adapter (not shown). The head substrate 3 is provided with two connectors 6 and 6, and each connector 6 is connected to a control device 36 (see FIG. 5) of the discharge inspection device 31 via a flexible flat cable (not shown). Yes. A drive voltage (drive waveform) output from the control device 36 (a head driver 88 described later) is applied to each piezoelectric element (piezo element) 17 via each connector 6, thereby causing each discharge nozzle 21 to output the drive voltage. Functional fluid is discharged. The droplet discharge head 1 discharges special ink or light-emitting resin liquid as a functional liquid, and is used to form a color filter of a liquid crystal display device, a light-emitting element that becomes each pixel of an organic EL device, or the like. It is done.

  As shown in FIG. 2 and FIG. 3, the head body 4 includes a double pump unit 11 constituted by the piezoelectric elements 17 and the like, a nozzle plate 12 having a nozzle surface 25 on which a plurality of discharge nozzles 21 are formed, have. Each pump part 11 is comprised from the mechanism part 13 which accommodated the piezoelectric element 17 corresponding to the number of the discharge nozzles 21, and the storage part 14 which stores a functional liquid. The storage unit 14 corresponds to the number of piezoelectric elements 17, and cavities 15 that temporarily store functional liquids, and a common chamber 16 that stores functional liquids supplied to the cavities 15 and communicates with the functional liquid introduction unit 2. , Is composed of. The functional liquid supplied from the functional liquid supply unit 56 flows into the common chamber 16 via the functional liquid introduction unit 2. Then, by applying a voltage to the piezoelectric element 17 to cause deformation, the functional liquid is introduced into the cavity 15 from the common chamber 16 using the volume change of the cavity 15 and the functional liquid is discharged from the discharge nozzle 21.

  The nozzle plate 12 is formed with a number of discharge nozzles 21 for discharging the functional liquid stored in the cavity 15. A large number of discharge nozzles 21 constitute two nozzle rows 22 arranged in parallel with each other and at a half-pitch position, and each nozzle row 22 has 180 discharge nozzles arranged at equal pitches. 21 (see FIG. 1B). In this case, of the 180 discharge nozzles 21, ten discharge nozzles 21 positioned at both outer ends are invalid discharge nozzles 23 and are not used for actual drawing. Therefore, in the discharge inspection, the discharge inspection is performed on the effective discharge nozzles 24 (total 160) excluding the invalid discharge nozzles 23 (total 20).

  Next, a discharge inspection apparatus 31 that inspects the discharge performance of the droplet discharge head 1 will be described with reference to FIG. The ejection inspection device 31 is placed on the machine base 32 and the head inspection device 33 that is placed on the machine base 32 and inspects the ejection performance of the liquid droplet ejection head 1. And a maintenance device 34 for maintaining and recovering the function of the ejection head 1, and these components are accommodated in a chamber 35. Further, a control device 36 (see FIG. 5) is provided outside the chamber 35, and controls the droplet discharge head 1, the head inspection device 33, and the maintenance device 34 in an integrated manner. In order to inspect the droplet discharge heads 1 one by one, the discharge inspection device 31 discharges a functional liquid with the head inspection device 33 while maintaining and recovering the function of the droplet discharge head 1 with the maintenance device 34. The ejection performance of the droplet ejection head 1 is inspected.

  The maintenance device 34 is arranged so as to be aligned with the suction device 37 and the suction device 37 for eliminating the discharge failure due to thickening or clogging of the functional liquid in the discharge nozzle 21, and wipes the nozzle surface 25 of the droplet discharge head 1. And a wiping device 38.

  The suction device 37 is in close contact with the nozzle surface 25 of the droplet discharge head 1 and also lifts and lowers the three caps 41 corresponding to the R, G, and B colors and the caps 41 to separate the droplet discharge head 1. It has a cap lifting mechanism 40 (see FIG. 5) in contact with it, and ejectors (not shown) connected to the three caps 41 via suction tubes (not shown). The suction device 37 closes each cap 41 to the nozzle surface 25 of the droplet discharge head 1 and performs suction with an ejector, thereby eliminating discharge defects due to clogging of the discharge nozzle 21 or the like.

  The wiping device 38 includes a wiping sheet 42 that contacts the nozzle surface 25, and a wipe sheet feeding mechanism 43 (see FIG. 5) that feeds and winds the wiping sheet 42. The wiping device 38 presses the wiping sheet 42 against the nozzle surface 25 of the discharge nozzle 21, and moves the discharge nozzle 21 back and forth in the Y-axis direction by the first Y-axis table 52, whereby the nozzle of the droplet discharge head 1 after the suction processing Wipe surface 25.

  The head inspection apparatus 33 supports a head holder 51 for setting a single droplet discharge head 1 without a tool, and supports the head holder 51, and moves the droplet discharge head 1 in the Y-axis direction via the head holder 51. A first Y-axis table 52; an imaging camera 53 that captures landing dots formed on an inspection sheet 71 described later; a second Y-axis table 54 that supports the imaging camera 53 and moves in the Y-axis direction; and a first Y-axis The table 52 is supported, the droplet discharge head 1 is moved in the X-axis direction via the first Y-axis table 52 and the head holder 51, the second Y-axis table 54 is supported, and imaging is performed via the second Y-axis table 54. A functional liquid supply unit 5 that supplies the functional liquid to the droplet discharge head 1 via an X-axis table 55 that moves the camera 53 in the X-axis direction and a supply tube (not shown). A flight inspection unit 57 for inspecting the flight bend and flight speed of the discharged functional liquid, a weight measuring unit 58 for measuring the discharge weight of the discharged functional liquid, a landing unit 59 having an inspection sheet 71, It has. The functional liquid supply unit 56 is attached to the X-axis table 55, and the flight inspection unit 57, the weight measurement unit 58, and the landing unit 59 are moved along the X-axis direction by the X-axis table 55. Are arranged side by side on the machine base 32 so as to face downward in the vertical direction.

  When the ejection performance of the droplet ejection head 1 is inspected by the head inspection device 33, the functional liquid is supplied from the functional liquid supply unit 56 to the droplet ejection head 1, and the X-axis table 55 and the first Y-axis table 52 are used. The droplet discharge head 1 is moved in the X-axis direction and the Y-axis direction so as to face the flight inspection unit 57, the weight measurement unit 58, and the landing unit 59, respectively, and each inspection and inspection discharge onto the inspection sheet 71 are performed. In addition, by the X-axis table 55 and the second Y-axis table 54, the imaging camera 53 is moved in the X-axis direction and the Y-axis direction, and each landing dot formed on the inspection sheet 71 of the landing unit 59 is imaged.

  The functional liquid supply unit 56 has three functional liquid tanks 61 for storing R, G, and B functional liquids, respectively, and each functional liquid tank 61 is disposed above the droplet discharge head 1. , And selectively used according to the set droplet discharge head 1. For this reason, the functional liquid is supplied to the droplet discharge head 1 from each functional liquid tank 61 via each supply tube by a natural water head.

  The flight inspection unit 57 is discharged from the illumination unit 65 having a pulse laser that is a pulse light source, a microscope camera 66 that is disposed opposite to the illumination unit 65 and receives pulsed light from the pulse laser, and the droplet ejection head 1. A functional liquid receiving portion 67 for receiving the functional liquid. When measuring the flight speed or inspecting the flight curve, the functional liquid is discharged while the illumination unit 65 and the microscope camera 66 are driven. The discharged functional liquid is blocked by the pulse laser between the illumination unit 65 and the microscope camera 66 and landed on the functional liquid receiver 67. Then, the flight speed is measured based on the result of the high-speed photographing by the flight inspection unit 57, and it is inspected whether there is a flight bend and whether there is a discharge failure.

  The weight measurement unit 58 includes a container 62 that receives the functional liquid discharged from the droplet discharge head 1 and an electronic balance 63 that measures the weight of the functional liquid in the container 62. When the discharge weight of the functional liquid is measured by the weight measuring unit 58, tens of thousands of functional liquids are discharged in units of the nozzle row 22 and the discharge weight of the functional liquid is measured by the electronic balance 63.

  The landing unit 59 includes a long inspection sheet 71 that receives inspection discharge from the droplet discharge head 1, a measurement stage 72 on which the inspection sheet 71 is placed, and an inspected portion of the inspection sheet 71 as a measurement stage 72. And an inspection sheet feeding mechanism 73 for feeding the inspection sheet 71 so as to send the unused portion to the measurement stage 72. When the landing dots formed on the inspection sheet 71 by inspection discharge are imaged by the imaging camera 53, the landing unit 59 sends the imaged portion by the inspection sheet feeding mechanism 73 and replaces it with an unused portion. The inspection discharge is received in the unused part. The measurement stage 72 preferably has a suction mechanism (not shown) and sets the inspection sheet 71 by suction.

  The long inspection sheet 71 is formed of a material that absorbs the functional liquid discharged from the discharge nozzle 21 and is formed of, for example, a film material or paper. When the functional liquid discharged from the discharge nozzle 21 lands on the inspection sheet 71, the functional liquid is absorbed by the inspection sheet 71, and circular landing dots are drawn (formed). In the present embodiment, the inspection sheet 71 is made of a material that absorbs the functional liquid, but a sheet that does not absorb the functional liquid and has a three-dimensional (dome-shaped) landing dot is used. Also good.

  As shown in FIG. 5, the control device 36 includes a drive control unit 81 having various drivers, and an overall control unit 82 that is connected to each unit and performs overall control of the ejection inspection apparatus 31 as a whole. The drive control unit 81 includes a droplet discharge driver 83, a camera driver 84, an XY movement driver 85, a wipe sheet feed driver 86, and a cap driver 87. The camera driver 84 drives the imaging camera 53 to capture the landing dots. The XY movement driver 85 drives the X-axis table 55, the first Y-axis table 52, and the second Y-axis table 54 to move the droplet discharge head 1 and the imaging camera 53 in the XY direction. The wipe sheet feeding driver 86 drives the wipe sheet feeding mechanism 43 of the wiping device 38 to feed the wiping sheet 42. The cap driver 87 drives the cap lifting mechanism 40 of the suction device 37 to bring the cap 41 into and out of contact with the nozzle surface 25.

  The droplet discharge driver 83 has four head drivers 88 and drives each discharge nozzle 21 of the droplet discharge head 1 to discharge droplets. Each head driver 88 has a DA converter (Digital to Analog Converter) (not shown), and is configured to be able to output different drive voltages (drive waveforms). That is, by selectively inputting four types of drive voltages from each head driver 88 to each piezoelectric element 17, each drive voltage can be selectively applied to each ejection nozzle 21. Hereinafter, a group of one or more ejection nozzles 21 to which a driving voltage is applied from a common head driver 88 is referred to as “COM”, and the COMs of the four head drivers 88 are “COM1”, “COM2”, “COM3”, respectively. And “COM4”. Although details will be described later, a plurality of ejection nozzles 21 to be driven are assigned to each COM and driven to perform droplet ejection.

  The overall control unit 82 has an interface 91 for connecting each means, a storage area that can be temporarily stored, a RAM 92 that is used as a work area for control processing, and various storage areas. ROM 93 for storing control programs and control data, hard disk 94 for storing various data from each means and processing programs for processing various data, programs stored in ROM 93 and hard disk 94, etc. Accordingly, a CPU 95 that performs arithmetic processing on various data and a bus 96 that connects them to each other are provided.

  The overall control unit 82 inputs various data from each unit via the interface 91 and causes the CPU 95 to perform arithmetic processing according to a program stored in the hard disk 94 (or sequentially read by a CD-ROM drive or the like). The processing result is output to each unit via the drive control unit 81 (various drivers). Thereby, the whole discharge inspection apparatus 31 is controlled, and various processes are performed.

  Here, with reference to FIG. 6, the discharge inspection operation and the appropriate voltage determination operation of the droplet discharge head 1 in the discharge inspection apparatus 31 will be described. As shown in FIG. 6, in the discharge inspection apparatus 31, after performing the discharge inspection operation (S1 to S9), the appropriate voltage determination operation (S10 to S10) is performed based on the data (discharge amount data) obtained by the discharge performance inspection. S14) is executed. First, the discharge inspection operation will be described. This discharge inspection operation is performed in a state where the droplet discharge head 1 is set in the head holder 51 in advance.

  As shown in FIG. 6, in the discharge inspection operation, first, the overall control unit 82 executes an initial filling step of filling the droplet discharge head 1 and the functional tube into the supply tube connected to the droplet discharge head 1. (S1). That is, the droplet discharge head 1 is made to face the suction device 37 by the X-axis table 55, the droplet discharge head 1 is sucked by the suction device 37, and the functional liquid is filled. Thereafter, the droplet discharge head 1 is driven to perform warm-up (temperature increase of the droplet discharge head 1), and the droplet discharge head 1 is made to face the wiping device 38. To finish the initial filling.

  When the initial filling is completed, a treatment flushing process is executed (S2). That is, the preliminary discharge is performed with the droplet discharge head 1 facing the weight measurement unit 58. Thereby, after cleaning, a certain amount of functional liquid is discarded and discharged, so that inspection can be performed from a state where a certain amount is discharged. For example, in the initial stage after cleaning, abnormal discharge does not occur, and abnormal discharge may occur when a certain amount of ink is discharged. By performing the treatment flushing, such an inspection defect can be prevented.

  Next, the droplet discharge head 1 is made to face the flight inspection unit 57, and the step of measuring the flight speed of each effective discharge nozzle 24 is executed (S3). The ejected functional droplet is photographed at high speed by the flight inspection unit 57, and the flight speed is measured based on the photographing result. At this time, the flight bend, ejection omission, and abnormal ejection are also inspected at the same time. When these inspections determine that the droplet ejection head 1 is defective, this operation is terminated.

  Thereafter, the droplet discharge head 1 is again brought into contact with the weight measurement unit 58, and a weight measurement step of discharge weight is executed (S4). In the weight measurement step, droplet discharge is performed from the droplet discharge head 1 to the weight measurement unit 58 in units of nozzle rows 22 and the discharge weight in units of nozzle rows 22 is measured. Based on this measurement result, a reference appropriate drive voltage (standard drive voltage) for each nozzle array 22 is determined. The reference appropriate drive voltage is a drive voltage used at the time of inspection ejection and a reference drive voltage when determining an appropriate drive voltage for each COM described later. The appropriate drive voltage is a voltage value of a drive voltage driven from the head driver 88 in order to discharge an appropriate discharge amount from one discharge nozzle 21. As a specific determination method, there is an approximate voltage value for discharging a target discharge weight (target discharge weight per nozzle row 22). In each nozzle row 22, two voltages before and after the voltage value are used. Carry out gravimetric measurements on values. Thereafter, based on the measurement result (each discharge weight at two voltage values), a linear function of the voltage value and the discharge weight per nozzle row 22 is obtained, and the target discharge weight is substituted into the linear function. The voltage value with respect to the target discharge weight is calculated. The voltage value obtained here is determined as a reference appropriate drive voltage.

  Next, a dot row forming step for forming a landing dot row for each nozzle row 22 by causing the droplet discharge head 1 to face the landing unit 59 and performing inspection discharge on the inspection sheet 71 of the landing unit 59. (Discharge process) is executed (S5). In the dot row forming step, each landing dot row is formed on the inspection sheet 71 based on the inspection discharge pattern. The test ejection pattern is data indicating whether or not each effective ejection nozzle 24 is ejected in each nozzle row 22, and here, as the test ejection pattern, the test ejection of a plurality of effective ejection nozzles 24 is thinned out in each nozzle row 22. The inspection ejection pattern to be used is used. Further, in this dot row forming step, the four COMs described above are assigned to the effective discharge nozzles 24 (hereinafter referred to as drive discharge nozzles) for inspection discharge alternately and sequentially from the end of each nozzle row 22 (nozzle assignment). Process). For example, the drive discharge nozzles are cyclically allocated from the end as COM1, COM2, COM3, COM4, COM1,. After assigning the respective drive discharge nozzles in this way, the drive voltage of each COM is set to the above-mentioned reference appropriate drive voltage, and the respective drive discharge nozzles are simultaneously driven to form a landing dot row. The inspection discharge from each drive discharge nozzle is constituted by a plurality of shots (for example, 4 shots) once, and each landing dot is constituted by a plurality of shots.

  When the landing dot row for each nozzle row 22 is formed, the overall control unit 82 causes the imaging camera 53 to face the landing unit 59 while retracting the droplet discharge head 1 by using the X-axis table 55, and sets each landing dot. An area measuring step for measuring the area of the area is executed (S6). That is, each landing dot of the landing dot row formed on the inspection sheet 71 is imaged by the imaging camera 53, and the area of each landing dot is measured based on the imaging result.

  When the area of each landing dot is measured, a discharge amount calculation step of calculating the discharge amount of each drive discharge nozzle based on the measurement result is executed (S7). Specifically, by substituting the area of each drive discharge nozzle into the regression equation representing the correlation between the area of the landing dots and the discharge amount of the drive discharge nozzle obtained in advance in the experiment, the discharge amount of each drive discharge nozzle Is calculated. Thereby, the discharge amount data including the discharge amount of each drive discharge nozzle with respect to the reference appropriate drive voltage is acquired. A value obtained by normalizing the discharge amount of each drive discharge nozzle with the average value of the whole may be used as the discharge amount data. In addition, the discharge amount measurement step described in the claims includes an area measurement step and a discharge amount calculation step.

  Next, a discharge amount correction step (S8) for correcting the discharge amount data with various correction values is executed. In the discharge amount correction step, first, a first drive number correction value and a DAC correction value for each COM are acquired. The first drive number correction value is a value for correcting a difference in discharge amount with respect to a difference in the number of discharge nozzles 21 that are simultaneously driven in inspection discharge (dot row forming process) (hereinafter referred to as the simultaneous drive number). On the other hand, the DAC correction value is a value for correcting a difference in discharge amount due to the characteristics of the DA converter. The overall control unit 82 stores in advance correspondence data indicating the correspondence relationship between the simultaneous drive number and the first drive number correction value, and extracts the first drive number correction value for the simultaneous drive number of each COM from the correspondence data. And get. In the dot row forming process, since all the drive ejection nozzles belonging to each COM are driven simultaneously, the number of drive ejection nozzles belonging to each COM is the number of simultaneous drive of each COM. Strictly speaking, as the corresponding data, a difference (simultaneous drive number difference) from the reference number (here, 12) and the first drive number correction value are stored in association with each other (FIG. 7 ( a)). For example, “+ 0.2% (= 1 + 0.002 = 1.002)” is used as the first drive number correction value for the simultaneous drive number “−1”, and “−0. 2% (= 1−0.002 = 0.998) ”is set as the first drive number correction value.

  On the other hand, the DAC correction value is calculated from the average discharge amount of each COM. That is, first, an average discharge amount for each COM is calculated from the discharge amount data. Since each drive discharge nozzle at the time of inspection discharge assigns each COM alternately from the end, the average discharge amount of each COM is only influenced by the simultaneous drive number difference and the DA converter characteristic difference. Therefore, the influence of the simultaneous drive number difference is canceled from the average discharge amount to obtain the DAC correction value. Specifically, the average discharge amount of each COM is multiplied by the first drive number correction value to obtain the DAC correction value of each COM.

  After obtaining the first drive number correction value and the DAC correction value for each COM, the first drive number correction value for each COM is multiplied by the discharge amount of all the drive discharge nozzles, and the DAC correction value is gradually calculated. ,to correct. Thereby, the overall control unit 82 acquires the discharge amount of each drive discharge nozzle for each corrected COM (discharge amount acquisition step), and acquires the corrected discharge amount data by combining them (total discharge amount acquisition step) ). Although details will be described later, the DAC correction value calculated here is used in the correction of the appropriate drive voltage (strictly, the voltage ratio correction step).

  Finally, the capping step of capping the droplet discharge head 1 with the cap 41 is performed with the droplet discharge head 1 facing the suction device 37 (S9). Thereby, the moisture retention state of the droplet discharge head 1 is maintained, and the discharge inspection operation is finished.

  Next, the proper voltage determining operation will be described. In the appropriate voltage determination operation, the COM of each drive discharge nozzle is reassigned and the appropriate drive voltage for each COM is determined using the discharge amount data obtained (corrected) in the discharge inspection operation. Here, in order to perform the same appropriate voltage determining operation in both nozzle rows 22, only the appropriate voltage determining operation of one nozzle row 22 will be described.

  As shown in FIG. 6, in the appropriate voltage determination operation, the overall control unit 82 first assigns a plurality of drive discharge nozzles in the nozzle row 22 to each COM based on the acquired discharge amount data of the nozzle row 22. The reassignment process to be corrected is executed (S10). In the reassignment step, a plurality of drive discharge nozzles are assigned to each COM depending on the discharge amount of each drive discharge nozzle. For example, when the number of drive discharge nozzles is 49, the top 12 drive discharge nozzles are defined as COM1, the 13th to 24th drive discharge nozzles as COM2, and the 25th to 36th drive as discharge volume order. The discharge nozzle is COM3, and the remaining drive discharge nozzles are COM4.

  Next, the overall control unit 82 executes an average discharge amount calculation step (S11) for calculating an average discharge amount for each COM based on the discharge amount data. That is, in each COM, the number of drive discharge nozzles of the COM is gradually calculated from the total discharge amount of the drive discharge nozzles to which the COM belongs. Thereby, the average discharge amount for each reassigned COM is calculated.

  Next, based on the calculated average discharge amount for each COM, a voltage ratio calculation step (appropriate voltage calculation step) for calculating a voltage ratio for each COM is executed (S12). The voltage ratio is the ratio of the appropriate drive voltage between the COMs, and determines the appropriate drive voltage of each COM as a coefficient. In the drive voltage calculation step, first, an average discharge amount of the entire droplet discharge head 1 (hereinafter referred to as an overall average discharge amount) is calculated from the discharge amount data. Next, a ratio between the average discharge amount of each COM and the overall average discharge amount (hereinafter referred to as a discharge amount ratio) is calculated. After calculating the discharge amount ratio of each COM, the voltage ratio of each COM is calculated based on this. Specifically, the voltage ratio of each COM is calculated from the discharge amount ratio of each COM using a conversion coefficient between the discharge amount ratio and the voltage ratio acquired in advance. For example, when the conversion coefficient is Ho and the discharge amount ratio is Iw, the value of Ho × Iw is the voltage ratio.

  When the voltage ratio of each COM is obtained, a ratio correction process (appropriate voltage correction process) (S13) for correcting the voltage ratio for each COM is executed. In the voltage ratio correction step, the voltage ratio for each COM is corrected based on the second drive number correction value and the DAC correction value. The second driving number correction value is a value for correcting a difference in ejection amount due to a difference in the number of simultaneous driving in the drawing process. That is, in the discharge amount correction step, the influence of the simultaneous drive number difference at the time of inspection discharge is canceled, whereas in this step, the influence of the simultaneous drive number difference at the drawing process is canceled. Specifically, the overall control unit 82 stores in advance correspondence data between the simultaneous drive number and the second drive number correction value at the time of the drawing process (see FIG. 7B). A second drive number correction value for the drive number is extracted. When the second drive number correction value for each COM is acquired, the second drive number correction value for each COM and the above DAC correction value are gradually corrected for each voltage ratio. Since the voltage ratio is a numerical value that determines an appropriate driving voltage, the appropriate driving voltage is indirectly corrected by correcting the voltage ratio.

  Since the voltage ratio of COM1 becomes the reference value, the second drive number correction value and the DAC correction value of COM1 are replaced with the COM ratio of COM1 instead of being subtracted from the COM1 voltage ratio. It is preferable to multiply the two drive number correction value and the DAC correction value. In addition, the number of simultaneous driving during the drawing process is basically the number of drive discharge nozzles belonging to each COM assigned in the above-described reassignment process, but is not limited to this. For example, before the drawing process In addition, the COM allocation may be performed again, or the drawing process may be performed by simultaneously driving only a part of all the drive ejection nozzles.

  Finally, an appropriate voltage calculation step (S14) for calculating an appropriate drive voltage for each COM from the voltage ratio for each COM and the above-described reference appropriate drive voltage is executed. Specifically, for each COM, the appropriate drive voltage for each COM is calculated by multiplying the voltage ratio by the reference appropriate drive voltage. Thereby, the appropriate drive voltage of each drive discharge nozzle is determined (appropriate voltage determination step).

  According to the configuration as described above, when acquiring the discharge amount, the measured discharge amount is corrected by the correction value (first drive number correction value) corresponding to the number of simultaneously driven in the dot row forming process (during inspection discharge). Thus, it is possible to cancel the change in the ejection amount according to the number of simultaneously driven. Therefore, it is possible to cope with the change in the discharge amount, and the discharge amount can be obtained with high accuracy.

  Further, when determining an appropriate driving voltage, the calculated voltage ratio is corrected by a correction value (second driving number correction value) corresponding to the simultaneous driving number at the time of the drawing process, whereby an ejection amount corresponding to the simultaneous driving number is obtained. The change can be canceled on the drive voltage side. Therefore, it is possible to cope with the change in the discharge amount, and to determine the appropriate drive voltage with high accuracy.

  In the present embodiment, four head drivers 88 are provided, and the ejection amount and the voltage ratio (appropriate driving voltage) are corrected according to the number of simultaneously driven driving ejection nozzles for each COM. However, one head driver is used. A configuration may be adopted in which the ejection amount and the voltage ratio (appropriate driving voltage) are corrected in accordance with the number of simultaneously driven driving ejection nozzles that are driven by the head driver 88.

  In the present embodiment, both the ejection amount and voltage ratio correction according to the simultaneous drive number difference and the ejection amount and voltage ratio correction according to the characteristic difference of the DA converter are implemented. Of these, only one of them may be implemented.

  Further, in the present embodiment, both the ejection amount correction according to the simultaneous drive number and the voltage ratio (appropriate drive voltage) correction according to the simultaneous drive number are performed. Only the implementation may be possible.

  Furthermore, in the present embodiment, the first drive number correction value and the DAC correction value are acquired separately, but the average discharge amount for each COM in the discharge amount of each drive discharge nozzle acquired in the discharge amount calculation step is calculated as follows. You may use as a correction value which combined 1 drive number correction value and DAC correction value. Since each average discharge amount is affected only by the influence of the simultaneous drive number difference of each COM and the characteristic difference of the DA converter as described above, the first drive number correction value and the DAC correction value are combined. It can be used as a correction value.

  In the present embodiment, in the dot row forming process (inspection discharge), all the drive discharge nozzles belonging to COM are driven simultaneously. However, the drive discharge nozzles belonging to COM are divided into two groups. Alternatively, the drive and discharge nozzles may be simultaneously driven at different timings for each group. In such a case, the discharge amount of each drive discharge nozzle is corrected for each group, with the drive discharge nozzles belonging to each group being the number of simultaneous drives.

  Here, with reference to FIG. 8, a droplet discharge apparatus 201 using the droplet discharge head 1 after the inspection will be described. The droplet discharge device 201 is incorporated in a flat panel display production line. For example, a droplet discharge head 1 into which a special ink or a functional liquid that is a light-emitting resin liquid is introduced, is used for a liquid crystal display device. A light-emitting element or the like that becomes each pixel of a color filter or an organic EL device is formed.

  As shown in FIG. 8, the droplet discharge device 201 is disposed on an X-axis support base 202 supported by a stone surface plate, and extends in the X-axis direction that is the main scanning direction, and moves the workpiece W to the X-axis. Are arranged on a pair of Y-axis support bases 205 spanned across the X-axis movement table 203 via a plurality of columns 204 and the X-axis movement table 203 to be moved in the direction. A Y-axis movement table 206 extending in the Y-axis direction, which is a sub-scanning direction orthogonal to the (X-axis direction), and a plurality of (12) droplet discharge heads suspended movably on the Y-axis movement table 206 1 includes 10 carriage units 207 individually mounted on the carriage, and a maintenance mechanism 208 that performs function maintenance / recovery processing of the plurality of droplet discharge heads 1. Further, the droplet discharge device 201 supplies these functional devices to the droplet discharge head 1 through the chamber mechanism 209 that houses these devices in an atmosphere in which temperature and humidity are controlled, and the chamber mechanism 209. A functional liquid supply mechanism 210 and a control computer (not shown) that controls each component of the droplet discharge device 201 are provided.

  The droplet discharge device 201 discharges and drives the droplet discharge head 1 in synchronization with the driving of the X-axis movement table 203 and the Y-axis movement table 206, so that the three-color functional liquid supplied from the functional liquid supply mechanism 210 is used. A droplet is ejected and a predetermined drawing pattern is drawn on the workpiece W. That is, drawing processing is performed by driving each droplet discharge head 1 while moving the workpiece W relative to each droplet discharge head 1. At this time, the control computer drives each droplet discharge head 1 with an appropriate drive voltage for each COM determined by the discharge inspection device 31.

  Thus, the drawing process for the workpiece W can be performed with high accuracy by determining the appropriate driving voltage of the droplet discharge head 1 using the appropriate voltage determining method that can determine the appropriate driving voltage with high accuracy. it can.

  In this embodiment, the droplet discharge head 1 is fixed, and the drawing process is performed by moving the workpiece W. However, the drawing process is performed by moving the droplet discharge head 1 relative to the workpiece W. If so, the drawing may be performed by fixing the workpiece W and moving the droplet discharge head 1.

  1: droplet discharge head, 21: discharge nozzle, 88: head driver, 201: droplet discharge device, W: work

Claims (5)

A method for acquiring a discharge amount of a droplet discharge head, which targets a droplet discharge head having one or more discharge nozzles driven by one head driver and acquires each discharge amount of the one or more discharge nozzles with respect to a standard drive voltage. There,
A discharge step of simultaneously driving the one or more discharge nozzles by the standard driving voltage from the head driver;
A discharge amount measuring step of measuring each discharge amount of the one or more discharge nozzles discharged in the discharge step;
A discharge amount correction step of correcting each of the measured discharge amounts of the one or more discharge nozzles with a correction value according to the number of simultaneously driven discharge nozzles driven simultaneously in the discharge step;
A discharge amount acquisition method for a droplet discharge head, comprising: a discharge amount acquisition step of acquiring each discharge amount of the corrected one or more discharge nozzles. A discharge amount of a droplet discharge head that targets each of the droplet discharge heads having a plurality of the discharge nozzles driven by two or more head drivers and obtains each discharge amount of the plurality of discharge nozzles with respect to the standard drive voltage An acquisition method,
A nozzle allocation step of allocating the plurality of discharge nozzles as the one or more discharge nozzles driven by the head drivers;
The discharge amounts of the one or more discharge nozzles that are acquired by the discharge amount acquisition method of the droplet discharge head according to claim 1 and that are driven by the two or more head drivers are combined to each discharge of the plurality of discharge nozzles. A discharge amount acquisition method for a droplet discharge head, comprising: a total discharge amount acquisition step of acquiring the amount as a volume. An average discharge amount of one or more discharge nozzles driven by each head driver is calculated based on the discharge amount of the plurality of discharge nozzles acquired by the discharge amount acquisition method of the droplet discharge head according to claim 2. An average discharge amount calculating step,
Based on the calculated average discharge amount for each head driver and the standard drive voltage, an appropriate voltage calculation step for calculating an appropriate drive voltage for the appropriate discharge amount for each head driver;
An appropriate voltage correction step for correcting the calculated appropriate drive voltage for each head driver by a correction value according to the number of simultaneous drive of the ejection nozzles that are simultaneously driven in the drawing process;
A method of determining an appropriate voltage for a droplet discharge head, comprising: an appropriate voltage determination step of determining the corrected appropriate drive voltage for each of the head drivers as an appropriate drive voltage for the plurality of discharge nozzles. A method for determining an appropriate voltage of a droplet discharge head, which targets a droplet discharge head having one or more discharge nozzles driven by one head driver, and determines an appropriate driving voltage for the one or more discharge nozzles,
An appropriate voltage calculating step for calculating an appropriate drive voltage for an appropriate discharge amount based on an average discharge amount of the one or more discharge nozzles with respect to a standard drive voltage;
An appropriate voltage correction step of correcting the calculated appropriate drive voltage by a correction value according to the number of simultaneous drive of the ejection nozzles that are simultaneously driven in the drawing process;
A method for determining an appropriate voltage for a droplet discharge head, comprising: an appropriate voltage determination step for determining the corrected appropriate drive voltage as an appropriate drive voltage for the one or more discharge nozzles. A liquid droplet ejection apparatus that drives the liquid droplet ejection head while moving the liquid droplet ejection head relative to the workpiece to perform a drawing process on the workpiece;
5. A droplet discharge apparatus that controls driving of the droplet discharge head based on the appropriate drive voltage determined by the method for determining an appropriate voltage of a droplet discharge head according to claim 3.

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