JP2011164017A - Device and method for measuring ink discharge quantity, and cantilever array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring an ink discharge quantity capable of easily measuring the ink discharge quantity in a short time. <P>SOLUTION: The device 1 for measuring the ink discharge quantity has a cantilever driving device 2 for naturally oscillating a cantilever 22, and an arithmetic unit 4 for calculating the discharge quantity of ink 50 discharged to the cantilever 22 by using a natural frequency of the cantilever 22 before and after discharging the ink 50 to the cantilever 22. When the cantilever 22 is oscillated, the cantilever 22 naturally oscillates at a natural frequency determined by a spring constant and an edge load of the cantilever 22. The natural frequency changes by the ink discharge quantity (more accurately, a solid mass obtained by drying the ink 50) discharged to the cantilever 22. Thus, the device detects the discharge quantity of the ink 50 discharged to the cantilever 22 by detecting a change of the natural frequency before and after the delivery of the ink 50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ink discharge amount measuring apparatus, an ink discharge amount measuring method, and a cantilever array.

  Inkjet technology, developed as one of the printing technologies on paper, has expanded its application range as technology advances, and in recent years, it has come to be used in industrial applications such as manufacturing methods for color filters for liquid crystal televisions. ing. As a method for forming a color filter using an ink jet technique, methods disclosed in Patent Documents 1 to 3 are known. In this method, an ink receiving portion is formed on a glass substrate, and the ink receiving portion is dyed by an ink jet technique to form a color filter.

  In this method, if the ink discharge amount is not uniform for all the nozzles of the inkjet head, the color density varies among pixels. Therefore, it is important that the ink discharge amount is uniform for all nozzles. Variations in the discharge amount of each nozzle are caused by variations in nozzle formation accuracy and piezoelectric element characteristics. Such variation in the discharge amount can be adjusted by the applied voltage waveform of the piezoelectric element. The problem lies in accurately measuring the discharge amount of each nozzle, which is a guideline for adjustment, in a short time.

  One method of measuring the ejection amount of each nozzle is to measure the ink mass or volume by reading the absorbance of ink landed on the substrate with a camera and performing image processing. This method is disclosed in Patent Documents 4 to 6 and the like. As another method, the amount of ink discharged from each nozzle (obtained by drying the ink) was obtained by landing the ink on a glass substrate and measuring the three-dimensional shape with a stereoscopic microscope using a scanning white interference method or the like. A method for estimating the volume of the thin film is disclosed in Patent Document 7.

JP-A-1-217302 JP-A-7-72325 JP 7-146406 A JP-A-9-48111 JP 2000-193814 A JP 2001-147317 A JP 2008-305668 A

  Problems of the methods of Patent Documents 4 to 7 are as follows. 1. It takes time to measure The measuring device is large. In particular, the problem of measurement time is very serious. This is because there are several tens of inkjet heads provided in the color filter manufacturing apparatus, and the total number of nozzles reaches tens of thousands. The measurement of the ink discharge amount for each nozzle must be performed at the time of replacement of the ink jet head or at regular inspections. At that time, the manufacturing cannot be resumed until the measurement of the discharge amount of all the nozzles is completed and the correction of the applied voltage is completed. This is a major impediment to increasing productivity.

  A first object of the present invention is to provide an ink discharge amount measuring apparatus and an ink discharge amount measuring method capable of easily measuring the ink discharge amount in a short time. A second object of the present invention is to provide a cantilever array suitable for such an ink discharge amount measuring apparatus and ink discharge amount measuring method.

  The ink discharge amount measuring apparatus according to the present invention uses the cantilever drive device for natural vibration of the cantilever and the natural frequency of the cantilever before and after discharging ink to the cantilever. And an arithmetic unit that calculates the discharge amount of the ink discharged.

  The cantilever is a band-shaped member with one end (base end) fixed and the other end (tip end) freely movable. When the cantilever is vibrated in a direction perpendicular to its main surface, the cantilever vibrates at a natural frequency determined by its spring constant and the tip load of the cantilever. The natural frequency varies depending on the amount of ink ejected onto the cantilever (more precisely, the mass of the solid content obtained by drying the ink). Therefore, by detecting a change in the natural frequency before and after ink ejection, it is possible to detect the amount of ink ejected onto the cantilever.

  In this method, only the cantilever and the vibration mechanism that vibrates it are necessary for measuring the ink ejection amount. The ink ejection amount can be easily detected by the change in the natural frequency of the cantilever before and after the ink ejection. Therefore, it is possible to easily detect the ink ejection amount in a short time without requiring a large-scale apparatus as in the prior art.

  The cantilever drive device includes an actuator that fixes one end of the cantilever and vibrates in a uniaxial direction, a vibration control device that changes the frequency of the actuator from a low frequency side to a high frequency side, It is desirable to have

  According to this configuration, by changing (sweeping) the vibration frequency of the actuator within a predetermined frequency range including the natural frequency of the cantilever beam, the cantilever beam can be reliably vibrated. The natural vibration of the cantilever has a plurality of natural vibration modes, but in order to calculate the tip load of the cantilever, it is necessary to detect which natural vibration mode it is vibrating. In that case, if the vibration control device changes the frequency of the actuator from the low frequency side to the high frequency side, the natural vibration mode that first enters the resonance state can be detected as the lowest natural vibration mode. it can. Therefore, it is possible to reliably detect in which natural vibration mode the vibration is performed, and it is possible to suppress calculation errors.

  A light source that emits light from one direction to the cantilever and a light receiving device that receives the light reflected in a specific direction by the cantilever, and the arithmetic unit receives light by the light receiving device. A resonance determination unit that detects the amount of reflected light from the cantilever and determines that the cantilever is oscillating naturally when the amount of light changes over time with a change amount equal to or greater than a predetermined change amount. It is desirable to have

  According to this configuration, the cantilever resonance state (natural vibration state) is detected by the following mechanism. First, when the cantilever is vibrated at a frequency lower than the natural frequency, the cantilever moves substantially in synchronism with the actuator without the tip portion being greatly bent. Therefore, the amount of light reflected by the cantilever does not change greatly. On the other hand, when the cantilever is vibrated at the natural frequency, the tip of the cantilever is bent greatly, so that a part of the reflected light is not received by the light receiving device, and the amount of light received by the light receiving device is large. Change occurs. Therefore, by measuring the change in the amount of light, it can be easily detected whether or not the cantilever is in a resonance state.

  According to this configuration, the resonance state of the cantilever can be easily detected by a change in the amount of reflected light from the cantilever. Only the light source and the light receiving device are necessary, and it is not necessary to add a special configuration to the cantilever or the actuator. In addition, the natural frequency can be detected more accurately than in the case where the resonance state is detected visually, and the measurement can be automated.

  The arithmetic device reads from the memory a memory that stores the vibration frequency of the actuator, and the vibration frequency of the actuator when the resonance determination unit determines that the cantilever beam is in natural vibration. It is desirable to include an ink discharge amount calculation unit that detects the amount of ink discharged to the cantilever using the natural frequency.

  According to this configuration, the natural frequency of the cantilever can be accurately detected.

  The light receiving device is a camera that photographs the plurality of cantilevers, and the resonance determination unit performs image processing on a captured image photographed by the camera, so that each of the cantilever beams received by the light receiving device is processed. It is desirable to detect the amount of reflected light.

  According to this configuration, it is possible to detect a change in the amount of reflected light from a plurality of cantilevers at a time. Therefore, work efficiency is improved.

  The arithmetic unit has a memory for storing a light amount of light received by the light receiving device, and the resonance determination unit detects a temporal change in the light amount using the light amount data stored in the memory, and It is desirable to detect the natural frequency of the cantilever on the basis of a change in the amount of light over time.

  According to this configuration, the natural frequency of the cantilever can be accurately detected.

  The light receiving device is a photodiode, and the memory preferably stores the light amount of the light detected by the photodiode at a cycle shorter than a vibration cycle of the natural vibration of the cantilever.

  According to this configuration, it is possible to detect in detail a temporal change in the amount of reflected light from the cantilever. Therefore, the resonance state can be determined quickly and accurately. When a high-speed response element such as a photodiode is used, information for each period of vibration can be obtained, and the natural frequency of the cantilever can be obtained from the output of the photodiode. In this case, it is not necessary to newly provide a device for detecting the natural frequency of the cantilever beam, and the device configuration is simplified.

  The actuator preferably has a mounting surface to which a plurality of cantilevers can be mounted.

  When the frequency of the actuator is changed from the low frequency side to the high frequency side, the resonance state is sequentially changed from the cantilever beams having a lower natural frequency among the plurality of cantilever beams attached to the actuator. Therefore, the natural frequencies of all the cantilevers can be obtained by simply sweeping the vibration frequency of the actuator at least once. Therefore, the working efficiency is greatly improved as compared to the case where each cantilever is measured separately.

  It is desirable to have a pressing plate that presses and fixes the base end portion of the cantilever on the actuator.

  According to this configuration, mechanical interference between the cantilevers can be suppressed, and the resonance state can be accurately detected.

  The ink ejection amount measuring method of the present invention includes a first step of ejecting ink onto a cantilever, a second step of detecting a natural frequency of the cantilever after ink ejection, and the cantilever after ink ejection. And a third step of calculating a discharge amount of the ink discharged to the cantilever using the natural frequency of the beam and the natural frequency of the cantilever before ink discharge. .

  According to this configuration, the ink discharge amount can be measured only by the cantilever and the vibration mechanism that vibrates the cantilever. The ink ejection amount can be easily detected by the change in the natural frequency of the cantilever before and after the ink ejection. Therefore, it is possible to easily measure the ink discharge amount in a short time without requiring a large-scale apparatus as in the prior art.

  In the second step, one end of the cantilever after ink discharge is fixed to an actuator, and the vibration is changed from a low frequency side to a high frequency side while vibrating the actuator in a uniaxial direction. Is desirable.

  According to this configuration, by changing (sweeping) the vibration frequency of the actuator within a predetermined frequency range including the natural frequency of the cantilever beam, the cantilever beam can be reliably vibrated. The natural vibration of the cantilever has a plurality of natural vibration modes, but in order to calculate the tip load of the cantilever, it is necessary to detect which natural vibration mode it is vibrating. In that case, if the vibration control device changes the frequency of the actuator from the low frequency side to the high frequency side, the natural vibration mode that first enters the resonance state can be detected as the lowest natural vibration mode. it can. Therefore, it is possible to reliably detect in which natural vibration mode the vibration is performed, and it is possible to suppress calculation errors.

  In the second step, the cantilever is irradiated with light from one direction, the amount of the light reflected in a specific direction by the cantilever is detected, and the amount of change is greater than or equal to a predetermined amount of change. It is desirable to determine that the cantilever beam is naturally oscillating when the time is changed.

  According to this configuration, the cantilever resonance state (natural vibration state) is detected by the following mechanism. First, when the cantilever is vibrated at a frequency lower than the natural frequency, the cantilever moves substantially in synchronism with the actuator without the tip portion being greatly bent. Therefore, the amount of light reflected by the cantilever does not change greatly. On the other hand, when the cantilever is vibrated at the natural frequency, the tip of the cantilever is bent greatly, so that a part of the reflected light is not received by the light receiving device, and the amount of light received by the light receiving device is large. Change occurs. Therefore, by measuring the change in the amount of light, it can be easily detected whether or not the cantilever is in a resonance state.

  According to this configuration, the resonance state of the cantilever can be easily detected by a change in the amount of reflected light from the cantilever. Only the light source and the light receiving device are necessary, and it is not necessary to add a special configuration to the cantilever or the actuator. In addition, the natural frequency can be detected more accurately than in the case where the resonance state is detected visually, and the measurement can be automated.

  In the second step, the vibration frequency of the actuator is stored in a memory, the vibration frequency of the actuator when it is determined that the cantilever beam is naturally vibrating, is read from the memory, and the vibration frequency is read from the memory. It is desirable to detect the natural frequency of the cantilever.

  According to this configuration, the natural frequency of the cantilever can be accurately detected.

  In the second step, a camera is used as a light receiving device that receives light reflected by the cantilever in a specific direction, the plurality of cantilevers are photographed by the camera, and the photographed images are image-processed. It is desirable to detect the amount of reflected light from each cantilever.

  According to this configuration, it is possible to detect a change in the amount of reflected light from a plurality of cantilevers at a time. Therefore, work efficiency is improved.

  In the second step, the amount of light reflected in a specific direction by the cantilever is stored in a memory, the time change of the amount of light is detected using the light amount data stored in the memory, and the amount of light It is desirable to detect the natural frequency of the cantilever beam based on the change over time.

  According to this configuration, the natural frequency of the cantilever can be accurately detected.

  In the second step, a photodiode is used as a light receiving device for receiving the reflected light reflected in a specific direction by the cantilever, and the period shorter than the vibration period of the natural vibration of the cantilever by the photodiode. It is desirable to store the amount of the light detected in step 1 in the memory.

  According to this configuration, it is possible to detect in detail a temporal change in the amount of reflected light from the cantilever. Therefore, the resonance state can be determined quickly and accurately. When a high-speed response element such as a photodiode is used, information for each period of vibration can be obtained, and the natural frequency of the cantilever can be obtained from the output of the photodiode. In this case, it is not necessary to newly provide a device for detecting the natural frequency of the cantilever beam, and the device configuration is simplified.

  In the first step, ink is ejected from different nozzles to a plurality of cantilevers, and in the second step, the plurality of cantilevers are attached to one actuator and simultaneously vibrated, and the frequency is reduced. It is desirable to detect the natural frequency of the cantilever for each of the cantilevers while changing from a few side to a high frequency side.

  When the frequency of the actuator is changed from the low frequency side to the high frequency side, the resonance state is sequentially changed from the cantilever beams having a lower natural frequency among the plurality of cantilever beams attached to the actuator. Therefore, the natural frequencies of all the cantilevers can be obtained by simply sweeping the vibration frequency of the actuator at least once. Therefore, the working efficiency is greatly improved as compared to the case where each cantilever is measured separately.

  It is desirable that the cantilever has an ink receiving portion at the tip.

  According to this configuration, the ink that has landed on the cantilever can be retained in the arrangement region of the ink receiving portion. Therefore, the calculation error of the natural frequency caused by the variation in the ink landing position is reduced, and the ink discharge amount can be accurately measured.

  The ink receiving portion is formed with a larger area than a circular region having an ink landing error as a radius, and the cantilever is arranged so that the calculation error of the natural frequency falls within a predetermined error range. Desirably, the spring constant of the cantilever is designed.

  The natural frequency of the cantilever beam depends on the spring constant and tip load of the cantilever beam. Variation in the ink adhesion position affects the magnitude of the tip load of the cantilever. Therefore, in order to reduce the calculation error of the natural frequency, it is desirable to reduce the variation in the ink adhesion position. The variation in the ink attachment position is determined by the size of the ink receiving portion. However, the ink receiving portion needs to be formed to a certain extent in consideration of ink landing errors. For example, by forming the ink in a larger area than the circular area having the radius of ink landing error, it is possible to suppress ink landing on the outside of the ink receiving portion. Therefore, in order to reduce the calculation error of the natural frequency, it is preferable to adjust the size of the spring constant of the cantilever. Since the spring constant is determined by the length and rigidity of the cantilever, it is possible to accurately measure the ink discharge amount by appropriately designing these sizes.

  The cantilever array of the present invention is characterized in that a plurality of cantilevers are arranged at regular intervals, the base ends thereof are connected to each other, and an ink receiving portion is provided at the tip of each cantilever. And

  According to this configuration, a cantilever array suitable for the above-described ink discharge amount measuring apparatus and ink discharge amount measuring method can be provided. The cantilever array includes a plurality of cantilevers. Therefore, if ink is ejected from different nozzles to a plurality of cantilevers, it is possible to measure the ejection amount of ink ejected from a plurality of nozzles at a time. In addition, since the ink receiving portion is provided at the tip of the cantilever, the ink that has landed on the cantilever can be reliably retained on the ink receiving portion. Therefore, it is possible to suppress a calculation error of the ink discharge amount due to the variation in the ink attachment position, and it is possible to accurately measure the ink discharge amount.

  It is desirable that at least a part of the surface of the portion other than the base end portion of the cantilever be a light reflecting surface.

  According to this configuration, the amount of reflected light from the cantilever can be increased. Therefore, measurement with less noise is possible.

The ink receiving portion may have the following configuration.
(A) A structure in which a lyophilic surface having high wettability with respect to ink and a lyophobic surface having low wettability with respect to ink are provided on the surface of the cantilever, and the lyophilic surface is used as an ink receiving portion.
(B) A structure in which a step portion is provided on the surface of the cantilever and the portion on the tip side of the step portion is an ink receiving portion.
(C) A configuration in which a layer of a liquid-absorbing polymer that absorbs ink or a layer obtained by solidifying a fibrous material is used as the ink receiving portion.

  (A) and (B) can be combined as appropriate. This increases the effect of holding ink. Since (C) is impregnated and held, the ink holding power is higher and the amount of ink that can be held is larger than (A) and (B). Even when the same nozzle is used, the ink discharge amount may vary. When comparing the average discharge amount between the nozzles, the measurement accuracy of the ink discharge amount can be increased as the number of ink landings is increased. For this reason, when the number of ink landings is increased and the measurement system of the average discharge amount is increased, the configuration (C) is suitable.

  It is desirable that the base end portion of the cantilever be larger in rigidity than other portions. When the base end portion of the cantilever is formed of the same member as the other portions, it is desirable that the thickness of the base end portion is larger than the thickness of the other portions.

  According to this configuration, mechanical interference between the cantilevers can be suppressed, and the resonance state can be accurately detected.

It is the schematic of the ink discharge amount measuring apparatus of 1st Embodiment. It is a top view of the cantilever array applied to an ink discharge amount measuring apparatus. It is the top view and sectional drawing of one cantilever which comprises a cantilever array. It is a figure which shows the other structural example of a cantilever. 6 is a flowchart illustrating an ink discharge amount measuring method. It is the schematic of the ink discharge amount measuring apparatus of 2nd Embodiment.

[First Embodiment]
FIG. 1 is a schematic diagram of an ink discharge amount measuring apparatus 1 according to the first embodiment.

  The ink discharge amount measuring device 1 includes a cantilever driving device 2 that vibrates the cantilever 22, a measuring device 3 that irradiates the cantilever 22 with light L1 and measures the light L2 reflected in a specific direction, and a measurement. The natural frequency of the cantilever 22 is detected based on the amount of reflected light measured by the apparatus 3, and the ink ejected to the cantilever 22 using the natural frequency of the cantilever 22 before and after ink ejection. And an arithmetic unit 4 that calculates 50 discharge amounts.

  The cantilever drive device 2 controls the actuator 10 that vibrates in one axial direction, the pressing plate 11 that sandwiches and fixes the base end portion 23 of the cantilever 22 between the actuator 10, and the frequency of the actuator 10. And a frequency measuring device 13 for detecting the vibration frequency of the actuator 10.

  The actuator 10 vibrates in the normal direction (vertical direction) of the light reflection surface 22 a of the cantilever 22 to excite the cantilever 22. As the actuator 10, a piezo actuator or the like is suitable. The piezo actuator can generate a mechanical displacement in one axial direction corresponding to the applied voltage by utilizing a characteristic that the piezo element deforms in proportion to the applied voltage. By applying the controlled oscillating voltage, it is possible to create a vibration having a desired frequency or vibration waveform. As a vibration method, it is desirable to vibrate with a sine wave. As another method of the actuator 10, an electromagnetic actuator such as a simpler voice coil type can be used.

  A plurality of cantilevers 22 are fixed on the mounting surface 10 a of the actuator 10. Although details will be described later with reference to FIG. 2, the cantilever beam 22 is used as a cantilever array 21 in which a plurality of cantilever beams 22 are connected by a base end portion 23. The actuator 10 has an attachment surface 10a to which a plurality of cantilevers 22 can be attached, and simultaneously excites the plurality of cantilevers 22 fixed to the attachment surface 10a.

  The vibration frequency of the actuator 10 is controlled by the vibration control device 12. The vibration control device 12 changes (sweeps) the frequency of the actuator 10 continuously or stepwise from the low frequency side to the high frequency side.

  The frequency measuring device 13 measures the vibration frequency of the actuator 10 and feeds back the measurement result to the vibration control device 12. Further, the measurement results are sequentially stored in the second memory 19. When the vibration control device 12 can control the vibration of the actuator 10 with high accuracy, the frequency measuring device 13 is not necessary. In that case, the frequency set by the vibration control device 12 is directly stored in the second memory 19.

  The measuring device 3 includes a light source 14 that emits light L1 toward the light reflecting surface 2a of the cantilever 22 and a light receiving device 15 that receives the light L2 reflected by the light reflecting surface 22a of the cantilever 22 in a specific direction. And having.

  As the light source 1, a known light source such as an LED can be used. Between the light source 1 and the cantilever 22, a collimating optical system (not shown) that collimates the light L <b> 1 and enters the light reflecting surface 22 a of the cantilever 22 can be provided.

  The light receiving device 15 is not particularly limited as long as it can receive the reflected light L2 and detect the change in the amount of light. In this embodiment, a camera is used as the light receiving device 15. The camera 15 performs imaging so that a plurality of cantilevers 22 attached to the actuator 10 can be accommodated in one captured image. The camera 15 photographs the cantilever 22 at a constant time interval from the start of vibration of the actuator 10 to the end of vibration. The camera 15 displays the lightest amount of light L2 reflected by the cantilever 22 so that the cantilever 22 is displayed brightest when the cantilever 22 is photographed without the actuator 10 vibrating. The position is fixed). Image data of images taken by the camera 15 is sequentially stored in the first memory 17.

  The arithmetic device 4 includes a first memory 17 that stores image data output from the camera 15, and a second memory 19 that stores the frequency of the cantilever 22 detected by the frequency measuring device 13 or the vibration control device 12. Then, the image data stored in the first memory 17 is analyzed (image processing), and the cantilever when the light amount of the light L2 reflected by the cantilever 22 is changing over time with a change amount greater than or equal to a predetermined change amount. Of the vibration frequency of the cantilever beam 22 stored in the second memory 19, the cantilever when the resonance determination unit 18 determines that the vibration state of the beam 22 is the resonance state. The amount of ink 50 ejected to the cantilever 22 is detected using the natural frequency of the cantilever 22 before and after ejecting the ink 50 to the cantilever 22 by detecting the frequency of the beam 22 as the natural frequency. Ink ejection to calculate Having an arithmetic unit 20, a.

  The arithmetic device 4 is realized by a computer system. The computer system includes a CPU that performs various operations as a processor and a memory that stores various information. The resonance determination unit 18 and the ink discharge amount calculation unit 20 embody some functions of the CPU. The operation of the CPU is stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer reading and executing this program.

  Examples of the computer-readable recording medium include a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory. Further, the computer program may be distributed to the computer through a communication line, and the computer that has received the distribution may execute the program.

  FIG. 2 is a plan view of the cantilever array 21 attached to the actuator.

  The cantilever array 21 is formed by arranging a plurality of cantilevers 22 at a constant interval W and connecting the base end portions 23 to each other. An ink receiving portion 24 for controlling the ink adhesion position is provided at the tip of each cantilever 22. The cantilever 22 is a thin flexible member formed in a band shape. One end portion (base end portion 23) of the cantilever 22 is fixed by an actuator and a pressing plate, and the other end portion (tip end portion) is freely movable.

  The cantilever array 21 is made of, for example, any one of a metal plate, a resin plate, a silicon plate, and a glass plate. The cantilever 21 is formed at a low cost by a known method such as punching of a metal plate or injection molding of a resin material.

  The cantilever array 21 may be entirely formed of the same member, or a part thereof may be formed of another member. It is possible to coat the surface of the cantilever array 21 with another member as long as the deformation of the cantilever 22 is not hindered. The cantilever 22 has a light reflecting surface 22a on the main surface on which light L1 (see FIG. 1) is incident, but the cantilever array 21 is formed of a material that absorbs or transmits light L1. In this case, a light reflecting film such as aluminum can be formed on a part or all of the surface of the cantilever array 21, and the surface of the cantilever array 21 can be used as a light reflecting surface.

  The thickness of the cantilever array 21 may be the same as a whole, or a part (for example, the base end portion 23) may have a different thickness. For example, the interference of vibration between adjacent cantilever beams 22 can be suppressed by forming the base end portion 23 to be thicker than the other portions and making the base end portion 23 more rigid than the other portions. Can do. When the rigidity of the base end portion 23 is very high, a structure for pressing the base end portion 23 from above by the pressing plate 11 (see FIG. 1) is not necessarily required.

  The interval W between the cantilevers 22 matches the interval between the nozzles of the inkjet head that ejects the ink 50 (see FIG. 1). For example, if the nozzle pitch of the inkjet head is 360 dpi, the pitch of the cantilever 22 is also 360 dpi. The number of cantilevers 22 matches the number of nozzles of the inkjet head, but if there are nozzles that are not used, it suffices that the number of cantilevers 22 be equal to the number of nozzles used. Each cantilever 22 corresponds to a different nozzle. Each cantilever 22 is ejected with ink from the corresponding nozzle toward the ink receiving portion 24.

  The size D of the ink receiving portion 24 is designed based on the size of ink droplets ejected from the nozzles, ink landing errors, and the like. For example, when the size of the ink droplets ejected from the nozzle is 20 μm to 40 μm and the landing error is 20 μm, the size D of the ink receiving portion is the ink ejected toward the center of the ink receiving portion 24. Even when the droplet has landed with the maximum landing error, the size is designed so as not to land outside the ink receiving portion 24, for example, 100 μm.

  FIG. 3A is a plan view showing an example of the configuration of the cantilever 22, and FIG. 3B is a cross-sectional view thereof.

  An ink receiving portion 24 for controlling the ink adhesion position is provided at the tip of the cantilever 22. In the cantilever beam 22 of FIG. 3, an ink receiving portion 24 on which ink easily adheres is formed at the tip of the cantilever beam 22 by utilizing the difference in wettability with respect to ink. Specifically, a lyophilic surface 26 having a high affinity for ink is formed at the tip of the cantilever 22 and a lyophobic surface 25 having a low affinity for ink is formed in other portions. Since the advancing contact angle is small on the surface of the lyophilic surface 26 and the advancing contact angle is increased on the surface of the liquid repellent surface 25, it is possible to suppress the ink from spreading to the liquid repellent surface 25 side.

The lyophilic surface 26 can be formed by performing UV ozone or O ₂ plasma treatment on the surface of the cantilever 22. The liquid repellent surface 25 can be formed by subjecting the surface of the cantilever 22 to fluorine plasma treatment. A lyophilic surface 26 and a lyophobic surface 25 are formed by forming a lyophilic film such as a silicon oxide film and a lyophobic film such as a fluororesin film or a silicon nitride film on the surface of the cantilever 22. Also good.

  FIG. 4A to FIG. 4D are cross-sectional views showing other configuration examples of the cantilever 22.

  In the cantilever 22 of FIG. 4A, a stepped portion 27 is formed at the tip of the cantilever 22, and the region on the tip of the stepped portion 27 is used as the ink receiving portion 24. The step portion 27 is formed by the edge of the thick portion formed at the tip of the cantilever 22. The thick portion may be formed by etching the same member as that of the cantilever 22 or may be formed by attaching a member different from the cantilever 22. The front surface 30 (the upper surface of the thick portion) of the stepped portion 27 is formed at a position higher than the base surface 31. Therefore, when the ink that has landed on the surface 30 reaches the stepped portion 27 through the surface 30, the contact angle with the cantilever 22 is suddenly reduced at the stepped portion 27, and further progress is suppressed.

  In the cantilever 22 in FIG. 4B, a stepped portion 28 is formed at the tip of the cantilever 22, and the region on the tip of the stepped portion 28 is used as the ink receiving portion 24. The step portion 28 is formed by a bent portion obtained by bending the tip end portion of the cantilever beam 22 into an L shape. A front surface 32 of the stepped portion 28 (an upper surface of the portion bent in an L shape) is formed at a position higher than the base surface 33. Therefore, when the ink that has landed on the surface 32 travels along the surface 32 and reaches the step portion 28, the contact angle with the cantilever 22 abruptly decreases at the step portion 28, and further progress is suppressed.

  In the cantilever 22 in FIG. 4C, a stepped portion 29 is formed at the tip of the cantilever 22, and the region on the tip of the stepped portion 29 is used as the ink receiving portion 24. The step portion 29 is formed by a ridge line portion of a protruding strip portion in which the tip end portion of the cantilever 22 is bent in a mountain shape. When the ink that has landed on the surface 34 on the front end side of the stepped portion 29 (the surface disposed on the front end side across the protruding portion) reaches the stepped portion 29 (ridge line portion of the protruding portion) through the surface 34, The contact angle with the cantilever 22 is suddenly reduced at the stepped portion 29, and further progress is suppressed.

  In the cantilever 22 in FIG. 4D, a liquid absorbing polymer layer 36 is formed at the tip of the cantilever 22, and this layer 36 is used as the ink receiving portion 24. For example, a porous layer in which a pigment is bound with a binder, such as that used for photo printing paper, can be used as the ink receiving portion 24. Alternatively, a layer 36 made of a fibrous material hardened may be formed on the surface of the cantilever 22 and the layer 36 may be used as the ink receiving portion 24. Since these structures are impregnated and held with ink, the holding power is high and the amount of ink that can be held is large. Even when the same nozzle is used, the ink discharge amount may vary. When comparing the average discharge amount between the nozzles, the measurement accuracy of the ink discharge amount can be increased as the number of ink landings is increased. Therefore, when the number of ink landings is increased and the measurement system of the average discharge amount is increased, the configuration of FIG.

  Note that the configurations shown in FIGS. 3 and 4 are examples, and these configurations can be implemented in appropriate combination.

  Here, the significance of providing the ink receiving portion 24 at the tip of the cantilever 22 will be described.

  In order to accurately obtain the amount of ink discharged on the cantilever 22, the ink landing position on the cantilever 22 must be accurately controlled. This is because if the landing position is shifted, the natural frequency of the cantilever 22 will be different even if ink of the same discharge amount is landed. However, when ink is ejected from the nozzles, variations in landing positions of about several tens of μm occur due to various factors, not only between the nozzles, but also the same nozzle. Therefore, in order to accurately measure the ink discharge amount, it is necessary to form the ink receiving portion 24 at a predetermined position of the cantilever 22 and keep the ink droplets in the distribution with a predetermined distribution.

  The ink receiving portion 24 needs to be formed in a large area in consideration of an ink landing error so that the ink does not land outside the ink receiving portion 24 when ink is ejected aiming at the ink receiving portion 24. Specifically, the ink receiving portion 24 is formed in an area wider than a circular region having a radius of ink landing error. Further, it is necessary to prevent ink droplets that have landed in the ink receiving portion 24 from flowing out of the ink receiving portion 24. The principle of preventing the landed ink droplets from flowing out of the ink receiving portion 24 utilizes the contact angle and surface tension between the liquid and the solid surface. When the ink droplet is further landed on the ink droplet adhering to the solid surface to increase the volume, the ink droplet tends to be spherical due to surface tension. Therefore, the contact angle between the solid surface and the ink droplet increases.

  However, since there is an advancing contact angle that cannot be exceeded between the liquid and the solid surface, the liquid droplets maintain the spherical surface under a constant volume and increase the contact area to increase the advancing contact angle. Advance the liquid end to match. The advancing contact angle is uniquely determined by the liquid and the solid surface. Accordingly, when a structure is provided such that the advancing contact angle increases outside the ink receiving portion 24, the contact angle reaches the advancing contact angle outside the ink receiving portion 24 due to the increase in volume of the droplet end that has reached the boundary portion. Stop moving forward. In other words, within an appropriate range of the volume of the droplet (the number of ink landings), the end of the droplet can be held at the boundary of the ink receiving unit 24, and thereby the position of the ink droplet can be controlled. .

  In order to reduce the calculation error of the natural frequency, it is desirable to reduce the size of the ink receiving portion 24. However, since the size of the ink receiving portion 24 is determined in consideration of an ink landing error, Some size is required. Therefore, in order to reduce the calculation error of the natural frequency, it is preferable to adjust the magnitude of the spring constant of the cantilever 22. Since the spring constant is determined by the length and rigidity of the cantilever 22, it is possible to accurately measure the ink discharge amount by appropriately designing these sizes.

  FIG. 5 is a flowchart for explaining the operation of the ink ejection amount apparatus 1.

In the ink discharge amount measuring method of the present embodiment, the step of discharging the ink 50 to the cantilever 22 and detecting the natural frequency f ₁ of the cantilever 22 (step S2, step S3), and the piece after ink discharge Using the natural frequency f ₁ of the cantilever 22 and the natural frequency f ₀ of the cantilever 22 before ink ejection, a step of calculating the ejection amount of the ink 50 ejected to the cantilever 22 (step S1, Step S4).

  The principle of measuring the ink discharge amount is as follows. When the cantilever 22 is vibrated in a direction perpendicular to its main surface (plate surface), the cantilever 22 resonates at a natural frequency f determined by its spring constant K and the tip load M of the cantilever 22 (formula (See (1)).

  The natural frequency f varies depending on the amount of ink ejected to the cantilever 22 (more precisely, the mass of the solid content obtained by drying the ink 50). Therefore, by detecting the amount of change in the natural frequency before and after the ink 50 is ejected, the ejection amount of the ink 50 ejected onto the cantilever 22 can be calculated.

  The natural frequency of the cantilever 22 before ink ejection may be the one measured by a test at the time of product shipment (the value described in the product specification of the cantilever beam), or ink may be ejected before ink ejection. What was measured with the discharge amount measuring apparatus 1 may be used.

  The cantilever 22 can be used for measuring the discharge amount of a plurality of inkjet heads. For example, after being used for measuring the discharge amount of the first inkjet head, it can be used for measuring the discharge amount of the second inkjet head.

  In this case, in the measurement of the ejection amount of the second inkjet, the mass of the ink ejected in the measurement of the ejection amount of the first inkjet head (more precisely, the mass of the solid content obtained by drying the ink) The tip load M of the cantilever 22 is increased as much as possible. Therefore, in the measurement of the discharge amount of the second inkjet head, it is necessary to acquire information on the natural frequency of the cantilever 22 before ink discharge by some method.

  Specifically, the natural frequency of the cantilever 22 after ink discharge stored in a memory (not shown) at the time of measuring the discharge amount of the first ink jet head is used as the ink at the time of measuring the discharge amount of the second ink jet head. There is a method of reading from the memory as the natural frequency of the cantilever before ejection. Further, when measuring the discharge amount of the second inkjet head, the natural frequency of the cantilever 22 before ink discharge may be measured again using the ink discharge amount measuring apparatus 1.

  Hereinafter, an example of the ink discharge amount measuring method will be described with reference to FIGS. 5, 1, and 2.

First, in step S1, it detects the natural frequency f ₀ of the cantilever 22 before the ink ejection. In step S1, first, the base end portion 23 of the cantilever 22 before ink ejection is fixed to the mounting surface 10a of the actuator 10, and the cantilever 22 is vibrated at a predetermined frequency in a direction perpendicular to the main surface. . Then, the vibration control device 12 changes (sweeps) the frequency of the cantilever 22 continuously or stepwise from the low frequency side to the high frequency side to uniquely determine the frequency of the cantilever 22 in the resonance state. It is detected as the frequency _{f 0.}

  Whether or not the resonance state is present is determined using the measuring device 3. The cantilever beam 22 is excited at the same frequency as the actuator 10 is vibrated, but moves substantially in synchronism with the actuator 10 when the frequency is smaller than the natural frequency. At this time, the bending of the cantilever 22 is slight, and most of the light L2 reflected by the light reflecting surface 22a of the cantilever 22 is incident on the camera 15. Therefore, the light reflection surface 22a of the cantilever 22 is observed brightly in the captured image captured by the camera 15.

  When the frequency of the actuator 10 is increased, the cantilever 22 is in a resonance state at the point where it matches the natural frequency. At this time, the amplitude of the tip of the cantilever 22 is in a state of being vibrated while being largely bent so as to exceed the excitation amplitude of the actuator 10. As the cantilever 22 bends, the angle of the light reflecting surface 22a from the horizontal plane changes, so that the reflected light L2 is reflected in a direction exceeding the numerical aperture (NA) of the camera 15. When this is observed with the camera 15 whose shutter speed is sufficiently slower than the vibration period, it is observed as a decrease in the amount of light on the light reflecting surface 22a of the cantilever 22.

  Image data of a photographed image photographed by the camera 15 is stored in the first memory 17. The resonance determining unit 18 performs image processing on the image data of the captured image stored in the first memory 17 and detects a change in the amount of reflected light from the light reflecting surface 22 a of the cantilever 22. When it is detected that the amount of reflected light has changed with time by a change amount equal to or greater than a predetermined change amount, the resonance determination unit 18 has the cantilever 22 in a resonance state (that is, has a natural vibration). ).

  On the other hand, the frequency of the actuator 10 is measured by the frequency measuring device 13 and stored in the second memory 19. The ink discharge amount calculation unit 20 reads the vibration frequency of the actuator 10 from the second memory 19 when the resonance determination unit 18 determines that the cantilever 22 is in the resonance state, and reads the vibration frequency of the cantilever 22. Detect as natural frequency.

  Strictly speaking, the frequency at which the cantilever 22 is in a resonance state has a certain width, and this width is generally expressed as a Q value. The natural frequency may be considered as the frequency at which the amplitude of the cantilever 22, that is, the deflection is maximized. When the deflection increases, the angle change of the light reflecting surface 22a with respect to the horizontal plane increases, and the amount of reflected light L2 observed by the camera 15 having a finite numerical aperture (NA) decreases. Therefore, the frequency at which the amount of reflected light is minimized may be the natural frequency.

  In the comb-shaped cantilever array 21 in which a large number of cantilevers 22 are connected, if the mechanical interference between the cantilevers is suppressed, the natural frequency of each cantilever 22 is determined independently. Therefore, when the entire cantilever array 21 is observed, it can be observed that the resonance state is sequentially increased from the cantilever 22 having a lower natural frequency as the frequency of the actuator 10 increases. In other words, the natural frequencies of all the cantilevers 22 can be obtained by merely sweeping the vibration frequency of the actuator 10 at least once.

Next, in step S <b> 2, ink 50 is ejected from the nozzles of the inkjet head to the ink receiving portion 24 of the cantilever 22. Each nozzle of the inkjet head is disposed to face the cantilever 22 of the corresponding cantilever array 21. Then, ink is ejected from each nozzle of the inkjet head to the ink receiving portion 24 of the corresponding cantilever 22. It is sufficient that at least one ink is landed, but even if the same nozzle is used, there is variation for each discharge. Therefore, in order to compare the average discharge amount between nozzles, the measurement accuracy can be increased as the number of ink landings is increased. . The ink is dried to form a solid film, and the tip load of the cantilever 22 is increased from M ₀ (before ink ejection) to M ₁ (after ink ejection) by the mass of the film.

Next, in step S3, measure the natural frequency f ₁ of the cantilever 22 after ink ejection. The measurement method of the natural frequency f ₁ is the same as the measurement method of the natural frequency f ₀ of the cantilever 22 before ink ejection. In step S2, the tip load of the cantilever 22 is increased from M ₀ to M _1, the natural frequency f ₁ after the ink ejection is smaller than the natural frequency f ₀ of the previous ink discharge.

Next, in step S4, the ejection amount of the ink 50 is calculated using the natural frequencies f ₀ and f ₁ before and after the ink 50 is ejected. The relationship between the natural frequency f of the cantilever 22 and the tip load M of the cantilever 22 is as shown in the equation (1). Therefore, the natural frequency f ₀ before ink ejection and the natural frequency f ₁ after ink ejection are substituted into the equation (1), and the tip load M ₀ before ink ejection and the tip load M ₁ after ink ejection are calculated. . Then, by calculating the difference _(M 1 -M _0), calculates the solid mass contained in the ink 50. Since the concentration of the solid content in the ink is known, the ejection amount of the ink 50 can be calculated based on the calculated mass of the solid content.

  Note that there may be an error in the calculation result of Expression (1) due to the fact that the size of the ink receiving portion 24 and the landing ink 50 as the load of the cantilever 22 is not 0, the influence of friction with air, and the like. . In that case, it is desirable to correct the error in advance by using another ink discharge amount measuring method in combination.

  In the ink discharge amount measuring apparatus 1 and the ink discharge amount measuring method described above, the discharge amount of the ink 50 can be easily detected using the natural frequency of the cantilever 22 before and after ink discharge. Therefore, it is possible to easily detect the ejection amount of the ink 50 in a short time without requiring a large-scale apparatus as in the prior art. In addition, by attaching a large number of cantilevers 22 to the actuator 10 and sweeping the frequency of the actuator once, the natural frequencies of all the cantilevers 22 are obtained. Therefore, the working efficiency is greatly improved as compared with the case where the discharge amount is measured for each nozzle.

[Second Embodiment]
FIG. 6 is a schematic diagram of the ink discharge amount measuring apparatus 5 of the second embodiment.

  The ink discharge amount measuring device 5 is different from the ink discharge amount measuring device 1 of the first embodiment in that a light source 40 composed of a laser light source and a light receiving device 41 composed of a photodiode are used as the measuring device 6. The light amount data of the reflected light L4 received by the photodiode 41 is stored in one memory 43, the light amount data stored in the first memory 43 is read, and the resonance determination unit 44 resonates the cantilever 22 Is a point to be determined. Therefore, the same components as those in the ink discharge amount measuring apparatus 1 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As many laser light sources 40 and photodiodes 41 as the number of cantilevers 22 provided in the cantilever array 21 are prepared. The laser light source 40 and the photodiode 41 are provided corresponding to the cantilever 22 in a 1: 1 ratio.

  The laser light source 40 irradiates the cantilever 22 with the light L3 at a constant time interval from the start of vibration of the actuator 10 to the end of vibration. The light L3 is irradiated on the light receiving surface 41a of the photodiode 41 so as to have a predetermined light spot size. For example, collimated light may be emitted from the laser light source 40, or an optical element such as a lens may be disposed between the light reflection surface 22 a of the cantilever 22.

  The position of the photodiode 41 is fixed so that the amount of received light of the light L4 reflected by the cantilever 22 is maximized when the cantilever 22 is irradiated with the light L3 without vibrating the actuator 10. Yes. The received light amount data received by the photodiode 41 is sequentially stored in the first memory 43.

  The arithmetic unit 7 stores a first memory 43 that stores data on the amount of received light output from the photodiode 41, and a second memory that stores the frequency of the cantilever 22 detected by the frequency measuring device 13 or the vibration control device 12. The received light amount data stored in the memory 19 and the first memory 43 is analyzed, and the light amount of the light L4 reflected by the cantilever 22 changes with time by a change amount greater than or equal to a predetermined change amount. The resonance determination unit 44 that determines that the vibration state of the cantilever 22 is the resonance state, and one of the frequencies of the cantilever 22 stored in the second memory 19 when the resonance determination unit 44 determines that the resonance state is the resonance state. The frequency of the cantilever 22 is detected as a natural frequency, and the ink 50 discharged to the cantilever 22 is discharged using the natural frequency of the cantilever 22 before and after discharging the ink 50 to the cantilever 22. Calculate quantity Has a ink discharge amount calculating unit 45, a.

  When a high-speed response element such as the photodiode 41 is used, information for each period of vibration can be obtained. The state of vibration of the cantilever beam 22 can be determined by the time per cycle in which the light spot crosses the light receiving surface 41 a of the photodiode 41. When the oscillation state of the reflected light L4 becomes large due to the resonance state, the moving distance of the light spot increases, while the size of the light spot and the light receiving surface of the photodiode 41 is finite and constant. , I.e., the time during which the signal from the photodiode 41 is observed is shortened. The resonance determination unit 44 detects the vibration state in which the time is minimized as the resonance state.

  The method for measuring the ink discharge amount is the same as the method described in the first embodiment. The difference is that the determination of the resonance state is performed by using the received light amount data of the photodiode 41 stored in the first memory 43.

  According to the ink discharge amount measuring device 5 and the ink discharge amount measuring method of the present embodiment, since a high-speed response element such as the photodiode 41 is used, information for each period of vibration can also be obtained. Therefore, the resonance state can be determined quickly and accurately.

  If the high-speed response of the photodiode 41 is used, the natural frequency can be measured using only the output of the photodiode 41. For example, the light L3 is emitted from the laser light source 40 at a period sufficiently shorter than the vibration period of the natural vibration of the cantilever 22 and the light amount detection by the photodiode 41 is sufficiently performed than the vibration period of the natural vibration of the cantilever 22. It shall be performed in a short cycle. Then, since the change in the amount of light can be detected in a cycle shorter than one cycle of the natural vibration of the cantilever 22, the natural frequency of the cantilever 22 can be detected by using the curve of the change in the amount of light.

  In this configuration, the resonance determination unit 44 determines the resonance state and also detects the natural frequency of the cantilever 22. The ink discharge amount calculation unit 45 calculates the discharge amount of the ink 50 using the natural frequency of the cantilever 22 detected by the resonance determination unit 44. In this case, it is not necessary to detect the natural frequency using the frequency measuring device 13 or the second memory 19. Therefore, these devices can be omitted or simplified. Therefore, the configuration of the cantilever drive device 2 can be simplified, and the ink discharge amount measuring device 5 can be further downsized.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Ink discharge amount measuring device, 2 ... Cantilever drive device, 3 ... Measuring device, 4 ... Calculation device, 5 ... Ink discharge amount measuring device, 6 ... Measuring device, 7 ... Calculation device, 10 ... Actuator, 10a ... Attached surface, 11 ... holding plate, 12 ... vibration control device, 13 ... frequency measuring device, 14 ... light source, 15 ... light receiving device (camera), 17 ... first memory, 18 ... resonance determination unit, 19 ... second memory, DESCRIPTION OF SYMBOLS 20 ... Ink discharge amount calculating part, 21 ... Cantilever array, 22 ... Cantilever, 22a ... Light reflecting surface, 23 ... Base end part, 24 ... Ink receiving part, 25 ... Liquid repellent surface, 26 ... Lipophilic surface , 27 ... step, 28 ... step, 29 ... step, 30 ... surface on the tip side of the step part, 31 ... surface on the base end side relative to the step part, 32 ... surface on the tip side of the step part, 33 ... from step part Also, the surface on the base end side, 34... The surface on the tip end side of the stepped portion, 35. 36, a liquid-absorbing polymer layer or a layer of fibrous material, 40, a light source, 41, a light receiving device (photodiode), 41a, a light receiving surface, 43, a first memory, 44, a resonance determining unit, 45. ... Ink discharge amount calculation unit, 50 ... Ink

Claims (26)

A cantilever drive for causing the cantilever to vibrate naturally;
And an arithmetic unit that calculates an ejection amount of the ink ejected to the cantilever using the natural frequency of the cantilever before and after ejecting the ink to the cantilever. Quantity measuring device.   The cantilever drive device includes an actuator that fixes one end of the cantilever and vibrates in a uniaxial direction, a vibration control device that changes the frequency of the actuator from a low frequency side to a high frequency side, The ink discharge amount measuring apparatus according to claim 1, comprising: A light source that emits light from one direction to the cantilever;
A light receiving device that receives the light reflected in a specific direction by the cantilever,
The arithmetic unit detects a light amount of reflected light from the cantilever beam received by the light receiving device, and the cantilever beam is inherent when the light amount is changed over time by a change amount equal to or greater than a predetermined change amount. The ink discharge amount measuring apparatus according to claim 2, further comprising a resonance determination unit that determines that the vibration is occurring.   The arithmetic device reads from the memory a memory that stores the vibration frequency of the actuator, and the vibration frequency of the actuator when the resonance determination unit determines that the cantilever beam is in natural vibration. And an ink discharge amount calculation unit that calculates a discharge amount of ink discharged to the cantilever using the natural frequency. The ink discharge amount measuring device according to claim 3. The light receiving device is a camera for photographing the plurality of cantilevers;
The said resonance determination part detects the light quantity of the reflected light from each cantilever beam light-received with the said light-receiving device by image-processing the picked-up image image | photographed with the said camera. Ink discharge amount measuring device.   The arithmetic unit has a memory for storing a light amount of light received by the light receiving device, and the resonance determination unit detects a temporal change in the light amount using the light amount data stored in the memory, and The ink discharge amount measuring apparatus according to claim 3, wherein a natural frequency of the cantilever is detected based on a temporal change in the amount of light. The light receiving device is a photodiode;
The ink discharge amount measuring apparatus according to claim 6, wherein the memory stores the light amount of the light detected by the photodiode at a period shorter than a vibration period of the natural vibration of the cantilever.   The ink ejection amount measuring apparatus according to claim 2, wherein the actuator has an attachment surface to which a plurality of cantilevers can be attached.   The ink discharge amount measuring apparatus according to claim 8, further comprising a pressing plate that presses and fixes a base end portion of the cantilever on the actuator. A first step of ejecting ink onto the cantilever;
A second step of detecting the natural frequency of the cantilever after ink ejection;
A third step of calculating an ejection amount of the ink ejected to the cantilever using the natural frequency of the cantilever after ink ejection and the natural frequency of the cantilever before ink ejection; A method for measuring the amount of ink discharged.   In the second step, one end of the cantilever after ink discharge is fixed to an actuator, and the vibration is changed from a low frequency side to a high frequency side while vibrating the actuator in a uniaxial direction. The ink discharge amount measuring method according to claim 10.   In the second step, the cantilever is irradiated with light from one direction, the amount of the light reflected in a specific direction by the cantilever is detected, and the amount of change is greater than or equal to a predetermined amount of change. The ink discharge amount measuring method according to claim 11, wherein it is determined that the cantilever beam is naturally oscillating when the time is changed.   In the second step, the vibration frequency of the actuator is stored in a memory, the vibration frequency of the actuator when it is determined that the cantilever beam is naturally vibrating, is read from the memory, and the vibration frequency is read from the memory. The ink discharge amount measuring method according to claim 12, wherein the ink discharge amount is detected as a natural frequency of the cantilever.   In the second step, a camera is used as a light receiving device that receives light reflected by the cantilever in a specific direction, the plurality of cantilevers are photographed by the camera, and the photographed images are image-processed. 14. The ink discharge amount measuring method according to claim 13, wherein the amount of reflected light from each cantilever is detected.   In the second step, the amount of light reflected in a specific direction by the cantilever is stored in a memory, the time change of the amount of light is detected using the light amount data stored in the memory, and the amount of light The ink discharge amount measuring method according to claim 12, wherein the natural frequency of the cantilever is detected based on a change with time.   In the second step, a photodiode is used as a light receiving device for receiving the reflected light reflected in a specific direction by the cantilever, and the period shorter than the vibration period of the natural vibration of the cantilever by the photodiode. The ink discharge amount measuring method according to claim 15, wherein the amount of the light detected in step 1 is stored in the memory. In the first step, ink is ejected from different nozzles to a plurality of cantilevers,
In the second step, the plurality of cantilevers are attached to one actuator and simultaneously vibrated, and the frequency is changed from the low frequency side to the high frequency side, and the cantilever is changed for each cantilever. The ink discharge amount measuring method according to any one of claims 11 to 16, wherein a natural frequency of the cantilever is detected.   18. The method of measuring an ink discharge amount according to claim 10, wherein the cantilever has an ink receiving portion at a tip portion thereof.   The ink receiving portion is formed with a larger area than a circular region having an ink landing error as a radius, and the cantilever is arranged so that the calculation error of the natural frequency falls within a predetermined error range. The ink discharge amount measuring method according to claim 18, wherein the spring constant of the cantilever is designed.   A cantilever array comprising a plurality of cantilevers arranged at regular intervals to connect base ends of the cantilevers and an ink receiving portion provided at the tip of each cantilever.   The cantilever array according to claim 20, wherein at least a part of the surface of the portion other than the base end portion of the cantilever is a light reflecting surface.   The surface of the cantilever is provided with a lyophilic surface having high wettability with respect to ink and a lyophobic surface having low wettability with respect to ink, and the lyophilic surface is used as the ink receiving portion. The cantilever array according to claim 20 or 21.   The cantilever array according to claim 20 or 21, wherein a stepped portion is provided on the surface of the cantilever, and a portion on the tip side of the stepped portion is the ink receiving portion.   The cantilever array according to claim 20 or 21, wherein the ink receiving portion comprises a layer of a liquid absorbing polymer that absorbs ink or a layer formed by solidifying a fibrous material.   The cantilever array according to any one of claims 20 to 24, wherein a base end portion of the cantilever has higher rigidity than other portions.   The base end portion of the cantilever is made of the same member as the other portions, and the thickness of the base end portion is larger than the thickness of the other portions. The described cantilever array.

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