JP2010260294A - Liquid droplet ejection device and method for ejecting liquid droplets - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet ejection device capable of obtaining desired printing quality while performing highly precise correction at a time of depositing of ink after ejecting the ink, and to provide a method for ejecting liquid droplets. <P>SOLUTION: This liquid droplet ejection device includes: a liquid droplet ejection head 5 having a plurality of nozzles for ejecting light curable ink and a plurality of drive elements provided corresponding to the plurality of nozzles; a work stage 16 for carrying, placed thereon, a recording medium 15 on which light curable ink ejected from the plurality of nozzles are deposited; a temperature measurement means 34 for measuring a temperature of the light curable ink ejected from the plurality of nozzles; a deposited diameter measurement means 32 that measures the deposited diameter of the light curable ink ejected from each of the plurality of nozzles to the recording medium 15 placed on the work stage 16 on the basis of a temperature change of the light curable ink measured by the temperature measurement means 34; and a control means 31 that regulates a drive waveform to be applied to the plurality of drive elements so as to regulate variation in the deposited diameters of the plurality of nozzles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge device and a droplet discharge method.

  In recent years, IC packages such as SiP (System in a Package), in which a plurality of IC chips are mounted in a single package to form a system, have become popular. As a marking technique for such an IC package, a laser marking technique is used as the IC package becomes thinner and smaller. On the other hand, from the viewpoints of damage to IC packages, visibility of marking, production efficiency, etc., instead of laser marking technology, it is based on a droplet discharge method using photo-curing (ultraviolet-curing) ink that is cured by ultraviolet irradiation. Marking technology is drawing attention.

  The difference between the ultraviolet curable ink and the ordinary water-based ink or oil-based ink is that it can be quickly cured by irradiating an appropriate amount of ultraviolet light after being placed on an IC package (recording medium). Due to such characteristics, the UV curable ink is not affected by the physical properties of the recording medium such as ink permeability, and stable printing quality can be obtained even when the ink is disposed on a non-receptive layer medium, for example. .

  By the way, in the marking technology for IC packages using ultraviolet curable ink, a UV lamp is generally mounted as a heat source. Along with this, the temperature change in the apparatus increases, and the amount of ink discharged varies when ultraviolet curable ink is discharged from a plurality of nozzles of the droplet discharge head. When drawing is performed with variations in the ink discharge amount, desired print quality may not be obtained. On the other hand, there is a technique for managing a temperature change in the apparatus uniformly by mounting a thermal chamber together with a UV lamp. However, the use of a thermal chamber results in high costs.

  Technologies for solving such problems have been studied. For example, in Patent Documents 1 and 2, in a low temperature range where the ink has high viscosity, the amount of heat generated by the droplet discharge head is increased, and the ink is The first drive waveform that increases the discharge speed is driven. On the other hand, in the high temperature range where the ink has a low viscosity, the ink is driven using the second drive waveform that reduces the heat generation amount of the droplet discharge head and decreases the ink discharge speed. Thereby, ink is discharged while maintaining the ink discharge speed, the temperature of the droplet discharge head, and the temperature of the discharged ink at stable values, and the deterioration of the print quality is suppressed.

JP-A-9-174831 Japanese Patent Laid-Open No. 9-201962

In the techniques of Patent Documents 1 and 2, it is considered that a decrease in print quality can be suppressed, but there are problems as follows.
In Patent Documents 1 and 2, a temperature corresponding to the viscosity of ink is detected before ink is ejected from a plurality of nozzles of a droplet ejection head, and predetermined driving is performed in a low temperature region of ink and a high temperature region of ink. It is driven using a waveform. For this reason, it is necessary to detect the temperature with high accuracy before ink discharge, and there is a limit to correct the correction at the time of ink landing after ink discharge to suppress the deterioration of print quality.

  The present invention has been made in view of such circumstances. Even when ultraviolet curable ink is used, high-precision correction at the time of ink landing after ink ejection is performed, and a desired print quality is achieved. It is an object to provide a droplet discharge apparatus and a droplet discharge method that can be obtained.

  In order to solve the above problems, a droplet discharge device of the present invention includes a plurality of nozzles that discharge photocurable ink, and a plurality of drive elements that are provided corresponding to the plurality of nozzles. A temperature for measuring a temperature of the discharge head, a work stage on which a recording medium for landing the photocurable ink discharged from the plurality of nozzles, and the photocurable ink discharged from the plurality of nozzles The photocuring discharged from the plurality of nozzles to the recording medium placed on the work stage based on a temperature change of the photocurable ink measured by the measuring means and the temperature measuring means A landing diameter measuring means for measuring the landing diameter of the mold ink, and a control means for adjusting a drive waveform applied to the plurality of driving elements so as to adjust a variation in the landing diameter of the plurality of nozzles. And having a, the.

  According to this configuration, the temperature of the photocurable ink ejected from the plurality of nozzles is measured by the temperature measuring unit. Based on the temperature change of the photocurable ink, the landing diameter of the photocurable ink ejected from the plurality of nozzles is measured by the landing diameter measuring means. Then, the drive waveform applied to the drive element is adjusted by the control means, and variations in the landing diameters of the plurality of nozzles are adjusted. That is, the variation in the ink discharge amount at the plurality of nozzles is corrected by the control means. For this reason, it becomes possible to discharge a uniform amount of photocurable ink from each nozzle of the droplet discharge head. The liquid droplet ejection apparatus according to the present invention does not require highly accurate temperature detection before ink ejection as in Patent Documents 1 and 2. That is, the landing diameter of the photocurable ink after ink ejection that directly contributes to the print quality is measured, and the dispersion of the landing diameter is corrected. Accordingly, it is possible to perform correction with high accuracy at the time of ink landing after ink ejection and obtain a desired print quality. In addition, since no thermal chamber is mounted, the cost can be reduced.

  The droplet discharge method of the present invention is a droplet discharge using a droplet discharge head having a plurality of nozzles for discharging photocurable ink and a plurality of drive elements provided corresponding to the plurality of nozzles. A first temperature measurement step of measuring the temperature of the photocurable ink ejected from the plurality of nozzles, and the photocurable ink is made constant with a drive waveform applied to the plurality of drive elements. A first landing process for landing on the recording medium; and after the first landing process, based on a temperature change of the photocurable ink measured by the first temperature measurement process, A first landing diameter measuring step for measuring a first landing diameter of the photocurable ink ejected from a plurality of nozzles, and a variation in the first landing diameter in the plurality of nozzles after the first landing diameter measurement step. To adjust the above A second landing step by adjusting the driving waveform applied to the number of drive elements landing the photocurable ink on the recording material, characterized by having a.

  According to this manufacturing method, the temperature of the photocurable ink ejected from the plurality of nozzles is measured in the first temperature measurement step. Then, in the first landing diameter measuring step after the first landing step, the landing diameter of the photocurable ink ejected from the plurality of nozzles is measured by the landing diameter measuring means based on the temperature change of the photocurable ink. The Then, the drive waveform applied to the drive element corresponding to each nozzle is adjusted so that the variation in the first landing diameter of the plurality of nozzles is adjusted by the second landing step, and the photocurable ink is landed on the recording medium. Is done. That is, the variation in the ink discharge amount of the plurality of nozzles is corrected by the second landing process. For this reason, it is possible to discharge a uniform amount of photocurable ink from each nozzle of the droplet discharge head. The droplet discharge method of the present invention measures the landing diameter of the photocurable ink after ink discharge that directly contributes to the print quality, and corrects the variation in the landing diameter. Accordingly, it is possible to perform correction with high accuracy at the time of ink landing after ink ejection and obtain a desired print quality.

In the droplet discharge method, the second temperature measurement step of measuring the temperature of the photocurable ink discharged from the plurality of nozzles after the second landing step, and the second temperature measurement step A second landing diameter measuring step of measuring a second landing diameter of the photocurable ink ejected from the plurality of nozzles to the recording medium based on the measured temperature change of the photocurable ink; Then, after the second landing diameter measurement step, the drive waveform applied to the plurality of driving elements is adjusted so as to adjust the variation in the second landing diameter of the plurality of nozzles, and the photocurable ink is applied to the cover. It is desirable to have at least one third landing step for landing on the recording medium.
According to this manufacturing method, after the second landing process, the temperature measurement process, the landing diameter measurement process, and the landing process are repeatedly performed a plurality of times, so that the variation in the ink discharge amount of the plurality of nozzles is reliably adjusted. . For this reason, it becomes possible to discharge a significantly uniform amount of photocurable ink from each nozzle of the droplet discharge head. Therefore, it is possible to ensure highly accurate correction at the time of ink landing after ink ejection and obtain a desired print quality.

It is a schematic diagram which shows schematic structure of the droplet discharge apparatus of this invention. It is a schematic diagram which shows schematic structure of a droplet discharge head. It is explanatory drawing of the method of forming marking on an IC package. It is a flowchart which shows the process of a droplet discharge method. It is a figure which shows the drive waveform applied to a drive element. It is a figure which shows the arrangement | positioning state of the photocurable ink before and after correction | amendment of the dispersion | variation in a landing diameter.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

  In the following description, the XYZ rectangular coordinate system shown in FIG. 1 is set, and each member will be described with reference to this XYZ rectangular coordinate system. In the XYZ orthogonal coordinate system, the X axis and the Y axis are set in a direction parallel to the work stage 16, and the Z axis is set in a direction orthogonal to the work stage 16. In the XYZ coordinate system in FIG. 1, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z axis is set to the vertically upward direction.

(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a droplet discharge device 1 according to the present invention. The droplet discharge device 1 discharges photocurable ink onto an IC package CA (see FIG. 3) on the magazine P, and irradiates the discharged photocurable ink with light to cure the photocurable ink. Marking such as letters / numbers and various patterns is drawn on the package CA.

  The droplet discharge apparatus 1 includes a work stage 16, a droplet discharge head 5, a tube 45, a tank 33, a landing diameter measurement camera 14, a control unit (control means) 31, an analysis unit (landing diameter measurement means) 32, a temperature. A measurement unit (temperature measurement means) 34, a thermocouple 46, a first wiring 41, a second wiring 42, a third wiring 43, and a fourth wiring 44 are provided.

  The work stage 16 is installed so as to be movable in the X-axis direction by a stage moving device (not shown). The work stage 16 holds the magazine P, which is transported from a transport device (not shown), on the XY plane by a vacuum suction mechanism (not shown).

  The droplet discharge head 5 is electrically connected to the control unit 31 via the first wiring 41. The droplet discharge head 5 has a plurality of nozzles N (see FIG. 2), and discharges droplets of photocurable ink based on drawing data and drive control signals input from the control unit 31. . The droplet discharge head 5 discharges photocurable inks corresponding to Y (yellow), C (cyan), M (magenta), and K (black), respectively. It is connected.

  The droplet discharge head 5 includes a bearing mechanism (not shown) such as a pole screw or a linear guide in the Y-axis direction and the Z-axis direction. The droplet discharge head 5 is movable in the Y-axis direction and the Z-axis direction based on the position control signal indicating the Y coordinate and the Z coordinate input from the control unit 31.

  The tube 45 is a photocurable ink supply tube that connects the tank 33 and the droplet discharge head 5. The tank 33 has four colors: Y (yellow) photocurable ink, C (cyan) photocurable ink, M (magenta) photocurable ink, and K (black) photocurable ink. The photocurable ink is stored. The tank 33 stores the photocurable ink of four colors and supplies the photocurable ink to the droplet discharge head 5 corresponding to the four colors via the tube 45.

  Here, the photocurable ink is a type that is cured by receiving light of a predetermined wavelength, such as an ultraviolet curable ink, and contains a monomer, a photopolymerization initiator, and a pigment corresponding to each color. Depending on the conditions, various additives such as surfactants and thermal radical polymerization inhibitors are blended. In addition, since such a photocurable ink usually has a different wavelength range of light (ultraviolet rays) to be absorbed depending on its component (formulation), the optimum value of the wavelength to be cured, that is, the optimum curing wavelength is also different for each ink. Is different.

  For example, an ultraviolet curable ink is prepared by adding an auxiliary agent such as an antifoaming agent or a polymerization inhibitor to a mixture of a vehicle, a photopolymerization initiator and a pigment. The vehicle is prepared by adjusting the viscosity of an oligomer, monomer or the like having photopolymerization curability with a reactive diluent.

  As the vehicle, monofunctional or polyfunctional polymerizable compounds can be used. More specifically, oligomers (prepolymers) such as polyester acrylate, epoxy acrylate, and urethane acrylate can be exemplified, and these materials can also be used as a reactive diluent for adjusting the viscosity as an ink.

  As the photopolymerization initiator, benzophenone series, benzoin series, acetophenone series, and thioxanthone series are widely used. More specifically, 4-benzoyl-N, N, N-trimethyl benzene methanenannium chloride, 2-hydroxy 3- (4-benzoyl-phenoxy) -N, N, N-trimethyl 1-propylene benzene l -N, N-dimethyl N- [2- (1-oxo-2-propenyloxy) ethyl] A quaternary ammonium salt-type water-soluble organic substance such as benzene methanol bromide can be used. This type of photopolymerization initiator has different ultraviolet absorption characteristics, reaction initiation efficiency, yellowing, and the like depending on its composition, so that it is properly used depending on the color of the ink.

  As the polymerization inhibitor, any compound that has radical scavenging ability and inhibits radical polymerization can be used. However, in consideration of discharge suitability in the droplet discharge device 1, at least one compound selected from hydroquinones, catechols, hindered amines, phenols, phenothiazines, and condensed aromatic ring quinones is preferable.

  Examples of hydroquinones include hydroquinone, hydroquinone monomethyl ether, 1-o-2,3,5-trimethylhydroquinone, 2-tert-butylhydroquinone and the like. Examples of catechols include catechol, 4-methylcatechol, 4-tert-butylcatechol and the like. Examples of hindered amines include compounds having a tetramethylpiperidinyl group.

  Examples of phenols include phenol, butylhydroxytoluene, butylhydroxyanisole, pyrogallol, gallic acid, gallic acid alkyl ester, and the like. Examples of phenothiazines include phenothiazine. Examples of the condensed aromatic ring quinones include naphthoquinone and the like.

  Further, the polymerization inhibitor may be carbon black or inorganic / organic fine particles having a polymerization-inhibiting functional group introduced on the surface. Examples of the polymerization-preventing functional group include a hydroxyphenyl group, a dihydroxyphenyl group, a tetramethylpiperidinyl group, and a condensed aromatic ring.

  A recording medium 15 is disposed at a position adjacent to the magazine P on the work stage 16. The recording medium 15 is a recording medium on which the landing diameter of the photocurable ink ejected from the plurality of nozzles N of the droplet ejection head 5 can be recorded. As the recording material 15, for example, a recording paper such as a substrate made of glass or metal, a PET film, a glossy photographic paper, or the like can be used.

  Further, the recording medium 15 is used for confirming the discharge state (nozzle omission and bending) of the plurality of nozzles N of the droplet discharge head 5 before production, that is, before drawing on the magazine P on the work stage 16. It is also something that can be done.

  The temperature measurement unit 34 is connected to the droplet discharge head 5 via a thermocouple 46. The temperature measuring unit 34 has a function of measuring the temperature of the photocurable ink discharged from the plurality of nozzles N of the droplet discharge head 5. The temperature measurement unit 34 is electrically connected to the control unit 31 via the fourth wiring 44. The temperature measurement unit 34 outputs the measured temperature data of the photocurable ink to the control unit 31.

  The landing diameter measuring camera 14 is disposed at a position facing the recording surface (upper surface) of the recording medium 15 on the work stage 16. The landing diameter measuring camera 14 photographs the landing diameter of the photocurable ink ejected from the plurality of nozzles N to the recording medium 15 based on the temperature change of the photocurable ink measured by the temperature measurement unit 34. It is a camera. The landing diameter measurement camera 14 is electrically connected to the analysis unit 32 via the second wiring 42. The impact diameter measuring camera 14 outputs image data of the impact diameter of the photocured ink that has been taken to the analysis unit 32.

  The analysis unit 32 has a function of measuring the landing diameter by performing image processing on the landing diameter image data of the photocurable ink taken by the landing diameter measuring camera 14. The analysis unit 32 is electrically connected to the control unit 31 via the third wiring 43. The analysis unit 32 outputs the measured data of the landing diameter of the photocurable ink at the plurality of nozzles N measured to the control unit 31.

  The control unit 31 adjusts the drive waveform applied to the droplet discharge head 5 having the drive element PZ (see FIG. 2) based on the landing diameter measurement data input from the analysis unit 32. And the dispersion | variation in the landing diameter of the photocurable ink in the some nozzle N is adjusted with the drive element PZ. That is, the variation in the landing diameter of the photocurable ink at the plurality of nozzles N is corrected.

  After the variation in the landing diameter of the photocurable ink at the plurality of nozzles N is corrected by the drive element PZ, the work stage 16 is moved by the stage moving device. The nozzle surface (lower surface) of the droplet discharge head 5 and the upper surface of the magazine P are disposed so as to face each other. Thereafter, the photocurable ink is discharged from the plurality of nozzles N of the droplet discharge head 5 to a predetermined position on the magazine P.

  Further, a light irradiation device (not shown) is disposed in the vicinity of the droplet discharge head 5 for all of the droplet discharge heads 5. The light irradiating device is for curing the photocurable ink discharged to the IC package CA on the magazine P, and is composed of a number of LEDs (light emitting diodes) in this embodiment. However, in the present invention, the present invention is not limited to the LED, and other than this, for example, a laser diode (LD), a mercury lamp, a metal halide lamp, a xenon lamp, an excimer lamp, or the like can be used as the light irradiation device.

  In the light irradiation apparatus including the LEDs according to the present embodiment, the light to be irradiated has a wavelength corresponding to the optimum curing wavelength of the photocurable ink ejected by the corresponding droplet ejection head 5. That is, as described above, each photocurable ink has an optimum curing wavelength depending on its component (formulation) and the like, and the light irradiation device has the optimum curing wavelength of the corresponding photocurable ink. It comes to irradiate light.

  FIG. 2 is a schematic diagram showing a schematic configuration of the droplet discharge head 5. 2A is a plan view of the droplet discharge head 5 as viewed from the work stage 16 (the side on which the photocurable ink is discharged), and FIG. 2B is a partial perspective view of the droplet discharge head 5. 2 (c) is a partial sectional view of one nozzle of the droplet discharge head 5. FIG.

As shown in FIG. 2A, the droplet discharge head 5 includes a plurality of (for example, 180) nozzles N _{1 to} N ₁₈₀ arranged in the Y-axis direction. A nozzle row NA is formed by the nozzles N _{1 to} N ₁₈₀ . Although FIG. 2A shows one row of nozzles, the number of nozzles and the number of nozzle rows provided in the droplet discharge head 5 can be arbitrarily changed, and the nozzles for one row arranged in the Y-axis direction are arranged as X. A plurality of rows may be provided in the axial direction.

As shown in FIG. 2 (b), the droplet discharge head 5, a vibration plate 20 that material supply hole 20a is provided which is connected to the tube 45, a nozzle plate 21 in which the nozzles _N 1 _{to N 180} is provided A liquid reservoir 22 provided between the vibration plate 20 and the nozzle plate 21, a plurality of partition walls 23, and a plurality of storage chambers 24 are provided. Drive elements PZ _{1 to} PZ ₁₈₀ are arranged on the vibration plate 20 corresponding to the nozzles N1 to N180. The drive elements PZ _{1 to} PZ ₁₈₀ are, for example, piezo elements.

The liquid reservoir 22 is filled with photocurable ink supplied through the material supply hole 20a. The storage chamber 24 is formed so as to be surrounded by the vibration plate 20, the nozzle plate 21, and a pair of partition walls 23. The storage chamber 24 is provided in a one-to-one correspondence with each of the nozzles N _{1 to} N ₁₈₀ . In addition, photocurable ink is introduced into the storage chambers 24 from the liquid reservoir 22 through supply ports 24 a provided between the pair of partition walls 23.

As shown in FIG. 2C, the drive element PZ ₁ is obtained by sandwiching a piezoelectric material 25 between a pair of electrodes 26. The drive element PZ ₁ is configured such that the piezoelectric material 25 contracts when a drive signal is applied to the pair of electrodes 26. The vibration plate 20 such drive elements PZ ₁ is disposed, wrinkles become integral with the drive element PZ ₁ applies a driving signal to the pair of electrodes 26 to the outside (opposite side of the accommodating chamber 24) at the same time It bends, and thereby the volume of the storage chamber 24 is increased.

When the volume of the storage chamber 24 increases, photocurable ink corresponding to the increased volume in the storage chamber 24 flows from the liquid reservoir 22 through the supply port 24a. Further, when the application of the drive signal to the drive element PZ ₁ is stopped from such a state, the drive element PZ ₁ and the diaphragm 20 both return to the original shape, and the storage chamber 24 also returns to the original volume. As a result, the pressure of the photocurable ink in the storage chamber 24 increases, and the photocurable ink droplet L is ejected from the nozzle N toward the magazine P.

  FIG. 3 is an explanatory diagram of a method for forming a marking on the IC package CA on the magazine P using the droplet discharge head 5. FIG. 3A is a schematic plan view of a magazine P that is a discharge target of photocurable ink. FIG. 3B is a partially enlarged plan view of the magazine P.

  In FIG. 3A, a plurality of IC packages CA are arranged on the surface of a large-area magazine P formed of glass, plastic or the like. As shown in FIG. 3B, each IC package CA is provided with a plurality of marking areas PX arranged in a dot shape. The marking areas PX are arranged in a matrix on each IC package CA, and a predetermined marking is formed by ejecting photocurable ink for each marking area PX.

  3B is the main scanning direction, and the direction perpendicular to the main scanning direction (the left-right direction in the drawing) is the sub-scanning direction. Place on P. Then, the photocurable ink is ejected from the plurality of nozzles N of the droplet ejection head 5 while the magazine P is moved (scanned) relative to the droplet ejection head 5 in the main scanning direction and the sub-scanning direction. Marking is formed by arranging photocurable ink in each marking area PX in the IC package CA on the magazine P.

  The droplet discharge head 5 is scanned a plurality of times for one IC package CA. For example, after the droplet discharge head 5 is scanned in the main scanning direction, the droplet discharge head 5 is moved (scanned) in the sub-scanning direction, and scanning is performed again in the main scanning direction. When one IC package CA moves from the left end to the right end (sub-scan), it returns to the left end of the IC package CA again, and scans in the main scanning direction at a position slightly different from the position where the ejection has already been performed. Then, by performing such scanning a plurality of times, the photocurable ink is selectively ejected to a predetermined marking area PX in the IC package CA to form a desired marking.

  In FIG. 3B, the droplet discharge head 5 is inclined with respect to the sub-scanning direction in order to match the pitch of the nozzles N of the droplet discharge head 5 with the pitch of the marking area PX. If the pitch of the nozzles N and the pitch of the marking area PX are set so as to satisfy a predetermined correspondence relationship, it is not necessary to tilt the droplet discharge head 5 obliquely.

  The marking is formed by arranging each color of Y (yellow), C (cyan), M (magenta), and K (black) in an appropriate arrangement form such as a so-called stripe arrangement, delta arrangement, mosaic arrangement, or the like. Therefore, in the ink ejection process shown in FIG. 3B, the droplet ejection head 5 that ejects the photocurable inks of Y, C, M, and K is provided for four colors Y, C, M, and K. Prepare in advance. Then, an array of markings of four colors Y, C, M, and K is formed on one magazine P by sequentially using these droplet discharge heads 5.

  By the way, in a marking technique for an IC package using photo-curing type (ultraviolet photo-curing type) ink, a UV lamp is generally used as a heat source. Along with this, the temperature change in the apparatus increases, and the amount of ink discharged varies when ultraviolet curable ink is discharged from a plurality of nozzles of the droplet discharge head. When the drawing is performed with variations in the ink discharge amount, the arrangement amount (landing diameter) of the photocurable ink on the IC package varies, and a desired print quality may not be obtained.

  FIG. 6 is a diagram showing the arrangement state of the photocurable ink on the recording medium 15 before and after correcting the variation in the landing diameter of the photocurable ink at the plurality of nozzles N. FIG. FIG. 6A shows the arrangement state of the photocurable ink before the correction of the variation in the landing diameter. FIG. 6B shows the arrangement state of the photocurable ink after the variation in the landing diameter is corrected. In FIG. 6, M (M1 to M5) indicates the arrangement state of the photocurable ink corresponding to the plurality of nozzles N arranged in the Y-axis direction described above. Further, MA (MA1 to MA5) indicates a photocurable ink arrangement row corresponding to a plurality of nozzle rows NA in which a plurality of nozzles arranged in the Y-axis direction are provided in the X-axis direction. Yes. As shown in FIG. 6A, when the arrangement state of the photocurable ink corresponding to the plurality of nozzles N and the plurality of nozzle arrays NA is seen, it is confirmed that there is variation in the landing diameter as a whole.

  Therefore, in the droplet discharge method of the present invention, a plurality of nozzles N are adjusted by adjusting the drive waveform applied to the drive element PZ of the droplet discharge head 5 before drawing on the magazine P before correction (before production). The step of adjusting the ejection characteristics of the photo-curable ink in the nozzle and adjusting the landing diameter of the photo-curable ink in the plurality of nozzles N is provided. Hereinafter, an example of the droplet discharge method of the present invention will be described.

(Droplet ejection method)
FIG. 4 is a flowchart showing the steps of the droplet discharge method of the present invention. In the droplet discharge method of the present invention, the “first temperature measurement step” (step S1) for measuring the temperature of the photocurable ink discharged from the plurality of nozzles N and the drive waveform applied to the drive element PZ are made constant. Based on the “first landing step” (step S2) for landing the photocurable ink on the recording medium 15 and the temperature change of the photocurable ink measured by the first temperature measuring step after the first landing step. Then, the “first landing diameter measuring step” (step S3) for measuring the first landing diameter of the photocurable ink landed on the recording medium 15, and the drive element PZ so as to adjust the variation of the first landing diameter. And a “second landing step” (step S4) in which the photo-curing ink is landed on the recording medium 15 by adjusting the drive waveform applied to the recording medium 15.

  First, the apparatus is positioned at a predetermined position to align the apparatus. Specifically, the work stage 16 is moved in the X-axis direction and disposed immediately below the droplet discharge head 5. Thereby, the recording medium 15 on the work stage 16 is arranged so as to face the plurality of nozzles N of the droplet discharge head 5.

  Next, the temperature of the photocurable ink discharged from the plurality of nozzles N is measured (step S1 in FIG. 4). Specifically, the temperature of the photocurable ink stored in the storage chamber 24 of the droplet discharge head 5 before being discharged from the plurality of nozzles N is measured. The temperature of the photocurable ink is measured by connecting a thermocouple 46 to the nozzle plate 21 of the droplet discharge head 5, for example. The temperature measurement of the photocurable ink is always performed, and the temperature change of the photocurable ink is detected.

  Next, with the drive waveform applied to the drive element PZ being constant, the photocurable ink is landed on the recording medium 15 (step 2 in FIG. 4). The photocurable ink is preferably landed in an appropriate arrangement form such as a stripe arrangement, a delta arrangement, or a mosaic arrangement in accordance with the marking area PX. Thereby, the discharge state before correction (when discharging to the recording medium 15) of the plurality of nozzles N of the droplet discharge head 5 and the discharge state after correction (when discharging to the magazine P) are reliably matched. To come.

  In addition, when the photocurable ink is landed on the recording medium 15, it is preferable that the ink be landed in a plurality of times. Specifically, first, the first ink is landed on a predetermined area on the recording medium 15. Next, the second ink is landed on a region where the first ink is not landed. Thereby, since the ink can be repeatedly landed on the recording medium 15 a plurality of times, the recording medium 15 can be used effectively without waste.

  Next, based on the temperature change of the photocurable ink measured in the first temperature measurement step, the landing diameter of the photocurable ink landed on the recording medium 15 is measured (step 3 in FIG. 4). Specifically, the landing diameter of the photocurable ink ejected from the plurality of nozzles N to the recording body 15 is photographed by the landing diameter measuring camera 14 disposed at a position facing the upper surface of the recording body 15. .

  Image data of the landing diameter of the photocurable ink photographed by the landing diameter measuring camera 14 is output to the analysis unit 32. The landing diameter of the photocurable ink is measured at an arbitrary timing such as every magazine P, every IC package CA, every scan (drawing). Then, the measurement data of the landing diameter of the photocurable ink at the plurality of nozzles N measured by the analysis unit 32 is output to the control unit 31.

  In the present embodiment, the methods disclosed in Patent Documents 1 and 2 detect the temperature corresponding to the viscosity of the ink before discharging the ink, and drive using a predetermined drive waveform in the low temperature range of the ink and the high temperature range of the ink. On the other hand, a method of measuring the discharge amount based on the landing diameter after ink discharge is used. As a result, it is possible to perform highly accurate correction at the time of ink landing after ink ejection.

  Next, the drive waveform applied to the drive element PZ is adjusted to land the photocurable ink on the recording material 15 (step 4 in FIG. 4). Specifically, the drive waveform applied to the drive element PZ provided for each of the plurality of nozzles N is adjusted by the control unit 31.

  FIG. 5 is a diagram showing a drive waveform applied to the drive element PZ. FIG. 5A is a diagram illustrating a first drive waveform Wa that suppresses the amount of heat generated by the droplet discharge head 5 and suppresses the temperature rise of the photocurable ink stored in the storage chamber 24. FIG. 5B is a diagram showing a second drive waveform Wb that increases the amount of heat generated by the droplet discharge head 5 and raises the temperature of the photocurable ink stored in the storage chamber 24.

  In FIGS. 5A and 5B, the horizontal axis represents time, and the vertical axis represents voltage. In FIG. 5A, the symbol Va is the peak value (voltage value) of the pulse signal of the first drive waveform Wa. In FIG. 5B, the symbol Wb1 is the first pulse signal in the second drive waveform Wb, the symbol Wb2 is the second pulse signal in the second drive waveform Wb, and the symbol Wb3 is the third pulse signal in the second drive waveform Wb. It is. Reference sign Vb1 is the peak value (voltage value) of the first pulse signal Wb1 in the second drive waveform Wb, reference sign Vb2 is the peak value (voltage value) of the second pulse signal Wb2 in the second drive waveform Wb, and reference sign Vb3 is the first value. This is the peak value (voltage value) of the third pulse signal Wb3 in the second drive waveform Wb.

  As shown in FIG. 5A, the first drive waveform Wa is composed of one pulse signal for ejecting a droplet L of the photocurable ink from the nozzle N. The pulse signal is formed by a voltage rising portion, a constant voltage portion, and a voltage falling portion, and has a trapezoidal wave. The value Va of the constant voltage portion of the pulse signal of the first drive waveform Wa is different for each droplet discharge head 5.

  As shown in FIG. 5B, the second drive waveform Wb is a second pulse signal Wb2 for ejecting the photocurable ink droplet L from the nozzle N, and the photocurable ink droplet L is ejected from the nozzle N. It consists of three pulse signals of a first pulse signal Wb1 and a third pulse signal Wb3 that are not allowed to be generated. Each pulse signal is formed by a voltage rising portion, a constant voltage portion, and a voltage falling portion, and has a trapezoidal wave.

  The voltage Vb2 of the constant voltage portion of the second pulse signal Wb2 in the second drive waveform Wb is substantially the same value as the voltage Va of the constant voltage portion of the pulse signal in the first drive waveform Wa (Vb2 = Va). In the second drive waveform Wb, the voltage Vb1 of the constant voltage portion of the first pulse signal Wb1 is smaller than the voltage Vb2 of the constant voltage portion of the second pulse signal Wb2 (Vb1 <Vb2). The voltage Vb3 of the constant voltage part of the third pulse signal Wb3 is smaller than the voltage Vb2 of the constant voltage part of the second pulse signal Wb2 (Vb3 <Vb2). The values of the voltage Vb1, Vb2, Vb3 of the constant voltage portion of each pulse signal of the second drive waveform Wb are different values for each droplet discharge head 5.

  The adjustment of the drive waveform applied to the drive element PZ provided for each of the plurality of nozzles N is performed so as to adjust the variation in the first landing diameters of the plurality of nozzles N. For example, the first drive waveform with respect to the drive element PZ corresponding to the nozzle N in the region where the landing diameter of the photocurable ink in the initial state (arrangement state of the photocurable ink before correction in FIG. 6) is relatively large. Wa is applied. On the other hand, the second drive waveform Wb is applied to the drive element PZ corresponding to the nozzle N in a region where the landing diameter of the photocurable ink in the initial state is relatively small. In this manner, the variation in the landing diameter of the photocurable ink generated between the plurality of nozzles N is corrected by the drive element PZ.

  Through the above steps, the variation in the discharge amount of the photocurable ink occurring between the plurality of nozzles N is adjusted. Thereby, the variation in the discharge amount of the photocurable ink at the plurality of nozzles N is corrected. That is, the variation in the landing diameter of the photocurable ink that occurred between the plurality of nozzles N in the initial state (before correction) in FIG. 6A is approximately averaged as shown after correction in FIG. be able to.

  According to the droplet discharge device 1 of the present embodiment, the temperature of the photocurable ink discharged from the plurality of nozzles N is measured by the temperature measurement unit 34. Then, the landing diameter of the photocurable ink ejected from the plurality of nozzles N is measured by the analysis unit 32 based on the temperature change of the photocurable ink. Then, the drive waveform applied to the drive element PZ is adjusted by the control unit 31, and the variation in the landing diameters of the plurality of nozzles N is adjusted. That is, the control unit 31 corrects the variation in the ink discharge amount of the plurality of nozzles N. For this reason, a uniform amount of photocurable ink can be discharged from each nozzle N of the droplet discharge head 5. The liquid droplet ejection apparatus 1 of the present invention does not require highly accurate temperature detection before ink ejection as in Patent Documents 1 and 2. That is, the landing diameter of the photocurable ink after ink ejection that directly contributes to the print quality is measured, and the dispersion of the landing diameter is corrected. Accordingly, it is possible to perform correction with high accuracy at the time of ink landing after ink ejection and obtain a desired print quality. In addition, since no thermal chamber is mounted, the cost can be reduced.

  According to the droplet discharge method of the present embodiment, the temperature of the photocurable ink discharged from the plurality of nozzles N is measured in the first temperature measurement step. Then, in the first landing diameter measurement step after the first landing step, the landing diameter of the photocurable ink ejected from the plurality of nozzles N is measured by the analysis unit 32 based on the temperature change of the photocurable ink. The Then, the driving waveform applied to the driving element PZ corresponding to each nozzle N is adjusted so that the variation in the first landing diameters of the plurality of nozzles N is adjusted by the second landing process, and the photocurable ink is recorded. Landed on the body 15. That is, the variation in the ink discharge amount of the plurality of nozzles N is corrected by the second landing process. For this reason, a uniform amount of photocurable ink can be discharged from each nozzle N of the droplet discharge head 5. The droplet discharge method of the present invention measures the landing diameter of the photocurable ink after ink discharge that directly contributes to the print quality, and corrects the variation in the landing diameter. Accordingly, it is possible to perform correction with high accuracy at the time of ink landing after ink ejection and obtain a desired print quality.

  In the above-described droplet discharge method, the measurement was performed by the second temperature measurement step for measuring the temperature of the photocurable ink discharged from the plurality of nozzles N and the second temperature measurement step after the second landing step. A second landing diameter measuring step for measuring a second landing diameter of the photocurable ink discharged from the plurality of nozzles N to the recording medium 15 based on a temperature change of the photocurable ink; and a second landing diameter. The third landing process of landing the photocurable ink on the recording medium 15 by adjusting the driving waveform applied to the plurality of driving elements PZ so as to adjust the dispersion of the recording element 15 may be provided at least once.

  According to this manufacturing method, after the second landing step, the temperature measurement step, the landing diameter measurement step, and the landing step are repeatedly performed a plurality of times, so that the variation in the ink discharge amount in the plurality of nozzles N is reliably adjusted. The For this reason, it becomes possible to discharge a significantly uniform amount of photocurable ink from each nozzle N of the droplet discharge head 5. Therefore, it is possible to ensure highly accurate correction at the time of ink landing after ink ejection and obtain a desired print quality.

  In the liquid droplet ejection apparatus 1 of the present embodiment, the analysis unit 32 is based on the temperature change of the photocurable ink measured by the temperature measurement unit 34 and the recording medium 15 placed on the work stage 16. However, the present invention is not limited to this, but has a function of measuring the landing diameter of the photocurable ink ejected from the plurality of nozzles N. For example, the analysis unit 32 may have a function of measuring the landing area of the photocurable ink instead of the landing diameter of the photocurable ink.

  In the droplet discharge method of the present embodiment, the pulse signal of the drive waveform is a trapezoidal wave in the step of adjusting the drive waveform applied to the drive element PZ, but is not limited thereto. For example, the pulse signal of the drive waveform may be a rectangular wave instead of the trapezoidal wave. The peak value (voltage value) of the drive waveform applied to the drive element PZ can be adjusted as appropriate for each droplet discharge head 5.

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 5 ... Droplet discharge head, 15 ... Recorded object, 16 ... Work stage, 31 ... Control unit (control means), 32 ... Analysis unit (landing diameter measurement means), 34 ... Temperature measurement unit (Temperature measuring means), PZ ... Drive element, N ... Nozzle

Claims (3)

A droplet discharge head having a plurality of nozzles for discharging photocurable ink, and a plurality of drive elements provided corresponding to the plurality of nozzles;
A work stage on which a recording medium for landing the photo-curable ink ejected from the plurality of nozzles is placed;
Temperature measuring means for measuring the temperature of the photocurable ink discharged from the plurality of nozzles;
Landing of the photocurable ink ejected from the plurality of nozzles to the recording medium placed on the work stage based on a temperature change of the photocurable ink measured by the temperature measuring unit. An impact diameter measuring means for measuring the diameter;
Control means for adjusting drive waveforms applied to the plurality of drive elements so as to adjust variations in the landing diameters of the plurality of nozzles;
A droplet discharge apparatus comprising: A droplet discharge method using a droplet discharge head having a plurality of nozzles for discharging photocurable ink and a plurality of drive elements provided corresponding to the plurality of nozzles,
A first temperature measuring step for measuring the temperature of the photocurable ink discharged from the plurality of nozzles;
A first landing step of landing the photocurable ink on a recording medium with a constant driving waveform applied to the plurality of driving elements;
After the first landing step, the photocurable ink ejected from the plurality of nozzles to the recording medium based on a temperature change of the photocurable ink measured in the first temperature measurement step. A first landing diameter measuring step of measuring the first landing diameter of
After the first landing diameter measurement step, the drive waveform applied to the plurality of driving elements is adjusted so as to adjust the variation in the first landing diameter among the plurality of nozzles, and the photocurable ink is recorded on the recording target. A second landing process to land on the body,
A droplet discharge method comprising: A second temperature measuring step for measuring the temperature of the photocurable ink discharged from the plurality of nozzles after the second landing step;
Based on the temperature change of the photocurable ink measured in the second temperature measuring step, the second landing diameter of the photocurable ink ejected from the plurality of nozzles to the recording medium is measured. A second landing diameter measurement step;
After the second landing diameter measurement step, the drive waveform applied to the plurality of driving elements is adjusted so as to adjust the variation of the second landing diameter in the plurality of nozzles, and the photocurable ink is recorded. A third landing process to land on the body;
3. The droplet discharge method according to claim 2, wherein the droplet discharge method is provided at least once.

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