JP2007111946A - Manufacturing method for liquid jetting apparatus, and liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a liquid quantity variation of delivered liquid droplets by uniforming a displacement amount of pressure generating means mounted on a liquid jetting head. <P>SOLUTION: A manufacturing method for a liquid jetting apparatus comprises an element driving process for driving a piezoelectric vibrator by supplying an evaluation pulse which includes a delivering element for elongating to displace the piezoelectric vibrator from an evaluation pulse generating circuit 61 to an actuator unit, a counter-electromotive force amplitude measuring process for measuring by a counter-electromotive force amplitude measuring circuit 62 an amplitude of a counter-electromotive force signal CF based on the residual vibration of the piezoelectric vibrator generated after supplying of the delivering element, and a combining process for determining a combination of actuator units to be mounted on a recording head on the basis of a size of the amplitude of the measured counter-electromotive force signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid ejecting apparatus and a liquid ejecting apparatus, and more particularly, includes a liquid ejecting head that ejects liquid droplets from nozzle openings by supplying a driving signal and operating pressure generating means. The present invention relates to a manufacturing method of a liquid ejecting apparatus and a liquid ejecting apparatus.

  The liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting liquid as droplets and ejects various liquids from the liquid ejecting head. As a typical example of this liquid ejecting apparatus, for example, an ink jet recording head (hereinafter simply referred to as a recording head) as a liquid ejecting head is provided, and recording paper is used as ink droplets from a nozzle opening of the recording head. Examples thereof include an image recording apparatus such as an ink jet printer that performs recording by forming dots by ejecting and landing on an ejection target such as the above. In recent years, liquid ejecting apparatuses have been applied not only to this image recording apparatus but also to various manufacturing apparatuses such as a manufacturing apparatus for color filters such as liquid crystal displays.

  Here, taking the ink jet printer (hereinafter simply referred to as a printer) as an example, this printer includes a series of ink flow paths including pressure chambers for introducing ink, nozzle openings leading to the pressure chambers, and pressure chambers. A recording head having a pressure generating means (for example, a piezoelectric vibrator) that causes pressure fluctuations in the ink is mounted, and a driving signal generating circuit for generating a driving signal to be supplied to the pressure generating means is provided. By supplying a driving signal from the generating circuit to the pressure generating means and driving the pressure generating means, the ink is ejected as ink droplets from the nozzle openings.

  In the recording head, the liquid amount (weight or volume) of ink droplets ejected from the nozzle opening and the flying speed increase or decrease in accordance with the driving voltage value of the driving signal supplied to the pressure generating means and the shape of the waveform. ing. Therefore, at the time of manufacturing the recording head, the drive voltage of the drive signal and the shape of the waveform are set so that the liquid amount and the flying speed of the ejected ink droplets are averaged to the target value (design value) ( For example, see Patent Document 1).

JP-A-11-277737

  The drive signal set as described above is commonly used for each pressure generating means, but since there is an individual difference in the amount of displacement of the pressure generating means, in a recording head equipped with a plurality of pressure generating means, In some cases, the amount of liquid when ink droplets are ejected using the drive signal varies from one pressure generating means to another. When this variation is large, various problems arise. For example, in the above printer, the sizes of the dots that have landed on the recording paper are not uniform, and there is a risk that the recorded image will be uneven.

  The present invention has been made in view of such circumstances, and an object thereof is to make the amount of displacement of the pressure generating means mounted on the liquid ejecting head uniform and reduce the variation in the liquid amount of the discharged droplets. .

The manufacturing method of the liquid ejecting apparatus of the present invention has been proposed in order to achieve the above object, and includes a plurality of pressure generating means capable of causing pressure fluctuation in the pressure chamber communicating with the nozzle opening and the liquid in the pressure chamber. A method of manufacturing a liquid ejecting apparatus including a liquid ejecting head that ejects liquid in a pressure chamber as droplets from a nozzle opening by operation of the pressure generating unit,
An element driving step of supplying a displacement waveform element for displacing the pressure generating means to the pressure generating means to drive the pressure generating means;
Back electromotive force amplitude measuring step for measuring the amplitude of the back electromotive force signal based on the residual vibration of the pressure generating means generated after supplying the displacement waveform element;
And a combination step of determining a combination of pressure generating means mounted on the liquid ejecting head on the basis of the amplitude of the measured back electromotive force signal.

  According to the above configuration, since the combination of the pressure generating means mounted on the liquid ejecting head is determined based on the amplitude of the back electromotive force signal based on the residual vibration after displacement of the pressure generating means, each pressure generating means The amount of displacement of can be made equal. As a result, even when droplets are ejected using a common drive signal in each pressure generating means, it is possible to reduce the variation in the liquid amount as much as possible.

  In the above configuration, it is desirable that the initial amplitude of the back electromotive force signal is measured in the back electromotive force amplitude measuring step.

  According to this configuration, the amplitude of the back electromotive force signal is larger at the initial stage and gradually converges with the passage of time, so that measurement accuracy can be improved by measuring the initial amplitude.

  In the combining step, it is desirable to combine the pressure generating means so that the amplitudes of the back electromotive force signals are substantially equal.

  In the element driving step, it is desirable to adopt a configuration in which the displacement waveform element is supplied to the pressure generating means in a state where the residual vibration of the pressure generating means at the previous driving has converged.

  According to this configuration, the amplitude of the back electromotive force signal can be accurately measured without being affected by the residual vibration caused by the previous drive.

  Further, in the back electromotive force amplitude measuring step, the potential difference between the peak detection stage for detecting the maximum value and the minimum value of the back electromotive force signal and the adjacent maximum value and minimum value detected in the peak detection stage is calculated. It is desirable to go through an amplitude acquisition stage that is obtained as the amplitude of the power signal.

  According to another aspect of the invention, there is provided a liquid ejecting apparatus including a liquid ejecting head including a pressure generating unit combined by the manufacturing method having any one of the above-described configurations.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following, an ink jet printer (hereinafter abbreviated as a printer) shown in FIG. 1 will be exemplified as the liquid ejecting apparatus of the invention.

  The printer 1 includes a recording head 2 that is a type of liquid ejecting head, a carriage 4 to which an ink cartridge 3 (a type of liquid storage member) is detachably attached, and a platen disposed below the recording head 2. 5, a carriage moving mechanism 7 that moves the carriage 4 on which the recording head 2 is mounted in the paper width direction of the recording paper 6 (a kind of discharge target), and a recording paper in a paper feeding direction that is orthogonal to the head moving direction. 6 schematically includes a paper feed mechanism 8 for transporting 6. Here, the paper width direction is the main scanning direction, and the paper feed direction is the sub-scanning direction. The ink cartridge 3 may be a type that is mounted on the carriage 4 or a type that is mounted on the housing side of the printer 1 and is supplied to the recording head 2 via an ink supply tube.

  The carriage 4 is attached while being supported by a guide rod 9 installed in the main scanning direction, and is configured to move in the main scanning direction along the guide rod 9 by the operation of the carriage moving mechanism 7. ing. The position of the carriage 4 in the main scanning direction is detected by the linear encoder 10, and a detection signal is transmitted as position information to a printer controller (not shown). Accordingly, the printer controller can control the recording operation (discharge operation) by the recording head 2 while recognizing the scanning position of the carriage 4 (recording head 2) based on the position information from the linear encoder 10.

  In addition, a home position serving as a scanning start point of the recording head 2 is set within the moving range of the recording head 2 and outside the platen 5. A capping mechanism 11 is provided at this home position. The capping mechanism 11 seals the nozzle surface of the recording head 2 with a cap member 11 ′ to prevent the ink solvent from evaporating from the nozzle openings 28 (see FIG. 2). The capping mechanism 11 is used for a cleaning operation in which negative pressure is applied to the sealed nozzle surface to forcibly suck and discharge ink from the nozzle openings 28.

  FIG. 2 is a partial cross-sectional view illustrating the configuration of the recording head 2. The recording head 2 includes a case 12, an actuator unit 13 (in a broad sense, pressure generating means) housed in the case 12, a flow path unit 14 joined to the bottom surface (tip surface) of the case 12, and the like. Yes. The case 12 is made of, for example, an epoxy-based resin, and a housing empty portion 15 for housing the actuator unit 13 is formed therein. The actuator unit 13 includes a plurality of piezoelectric vibrators 16 (pressure generating means in a narrow sense) cut into comb teeth and a fixing plate 17 to which the piezoelectric vibrators 16 are joined. As will be described later, the recording head 2 in the present embodiment is configured to be able to eject a total of four colors of ink, and a total of four nozzle rows corresponding to each color are formed on the nozzle plate 22. The recording head 2 is mounted with a total of four actuator units 13 corresponding to each nozzle row.

  A flexible cable 18 is connected to each piezoelectric vibrator 16 of the actuator unit 13, and a drive signal from the drive signal generation circuit 43 (see FIG. 3) is supplied through the flexible cable 18. Note that the piezoelectric vibrator 16 in the present embodiment is a so-called longitudinal vibration mode piezoelectric vibrator that is displaced in a direction orthogonal to the electric field direction, and is orthogonal to the stacking direction of the piezoelectric body and the electrodes when a drive signal is supplied. Displaces (stretches) in the direction. Details of the piezoelectric vibrator 16 will be described later.

  The flow path unit 14 is configured by joining a nozzle plate 22 (a kind of nozzle forming member) to one surface of the flow path forming substrate 21 and a diaphragm 23 to the other surface of the flow path forming substrate 21. Yes. The flow path unit 14 is provided with a reservoir 24, an ink supply port 25, a pressure chamber 26, a nozzle communication port 27, and a nozzle opening 28. A series of ink flow paths from the ink supply port 25, the pressure chamber 26, and the nozzle communication port 27 to the nozzle opening 28 are formed corresponding to each nozzle opening 28.

  The nozzle plate 22 is a thin metal plate having a plurality of nozzle openings 28 formed in a row at a pitch (for example, 180 dpi) corresponding to the dot formation density. In the present embodiment, the nozzle plate 22 is made of a stainless steel plate, and a plurality of rows (nozzle rows) of nozzle openings 28 are provided. One nozzle row is composed of, for example, 180 nozzle openings 28. The recording head 2 in the present embodiment has different colors of ink (one type of liquid in the present invention), specifically cyan (C), magenta (M), yellow (Y), and black (K). Four ink cartridges 3 storing a total of four colors of ink can be mounted, and a total of four nozzle rows are formed on the nozzle plate 22 corresponding to these colors.

  The diaphragm 23 has a double structure in which the elastic film 30 is laminated on the surface of the support plate 29. In the present embodiment, the vibration plate 23 is manufactured using a composite plate material in which a stainless plate, which is a kind of metal plate, is used as the support plate 29 and a resin film is laminated on the surface of the support plate 29 as the elastic film 30. The diaphragm 23 is provided with a diaphragm portion 31 that changes the volume of the pressure chamber 26 and a compliance portion 32 that seals a part of the reservoir 24.

  The diaphragm portion 31 is produced by partially removing the support plate 29 by etching or the like. That is, the diaphragm portion 31 includes an island portion 33 to which the tip end surface of the piezoelectric vibrator 16 is joined, and a thin elastic portion 34 surrounding the island portion 33. The compliance section 32 is produced by removing the support plate 29 in the region facing the opening surface of the reservoir 24 by etching processing or the like in the same manner as the diaphragm section 31, and reduces the pressure fluctuation of the liquid stored in the reservoir 24. Functions as a damper to absorb.

  Since the tip surface of the piezoelectric vibrator 16 is joined to the island portion 33, the volume of the pressure chamber 26 can be changed by extending and contracting the free end portion of the piezoelectric vibrator 16. As the volume changes, pressure fluctuations occur in the ink in the pressure chamber 26. The recording head 2 ejects ink droplets from the nozzle openings 28 using this pressure fluctuation.

  FIG. 3 is a block diagram illustrating an electrical configuration of the printer 1. The printer 1 in the present embodiment is schematically configured by a printer controller 35 and a print engine 36. The printer controller 35 stores an external interface (external I / F) 37 to which print data from an external device such as a host computer is input, a RAM 38 for storing various data, and a control program for various controls. ROM 39, a nonvolatile storage element 40 such as an EEPROM or a flash ROM, a control unit 41 that performs overall control of each unit according to a control program stored in the ROM 39, an oscillation circuit 42 that generates a clock signal, A drive signal generation circuit 43 (a type of drive signal generation means) that generates a drive signal to be supplied to the recording head 2 and the ejection data and drive signals obtained by developing the print data for each dot are supplied to the recording head 2. And an internal interface (internal I / F) 44 for output.

  The print engine 36 includes a recording head 2, a carriage moving mechanism 7, a paper feed mechanism 8, and a linear encoder 10. The recording head 2 generates pulse selection data by translating the discharge data from the latch circuit 47, the latch circuit 47 that latches the discharge data set in the shift register 46, the shift register 46 in which the discharge data is set. A decoder 48, a level shifter 49 that functions as a voltage amplifier, a switch circuit 50 that controls supply of drive signals to the piezoelectric vibrator 16, and the piezoelectric vibrator 16 are provided.

  The control unit 41 develops the print data transmitted from the external device into ejection data corresponding to the dot pattern and transmits it to the recording head 2. In this case, the control unit 41 reads the print data in the reception buffer, converts it into intermediate code data, and stores this intermediate code data in the intermediate buffer. Then, the control unit 41 analyzes the intermediate code data read from the intermediate buffer, and expands the intermediate code data into ejection data (dot pattern data) for each dot with reference to font data, graphic functions, and the like in the ROM 39. The developed discharge data is temporarily stored in the output buffer, and when one line of discharge data corresponding to one main scan is obtained, this one line of discharge data is transferred to the recording head 2 through the internal I / F 44. Serial transmission. When ejection data for one line is transmitted from the output buffer, the contents of the intermediate buffer are erased and conversion to the next intermediate code data is performed. The recording head 2 ejects ink droplets based on the received ejection data.

  The drive signal generation circuit 43 generates a drive signal COM having a predetermined waveform shape. The printer 1 according to the present embodiment can perform multi-tone recording in which dots having different sizes are formed on a recording paper (a kind of ejection target) by ejecting ink droplets having different liquid amounts. The recording operation is possible with four gradations of dots, small dots, and non-recording. Then, as shown in FIG. 4, for example, the drive signal generation circuit 43 connects the ejection pulse DP1, the ejection pulse DP2, the ejection pulse DP3, and the micro-vibration pulse DP4 for causing micro-vibration of the meniscus during non-recording. A drive signal COM configured as described above is generated.

  The drive signal COM illustrated in FIG. 4 is a drive signal used for relatively high-speed recording such as text printing, and the ejection pulses DP1 to DP3 all have the same waveform shape. For example, by supplying only the ejection pulse DP2 to the piezoelectric vibrator 16, small dots are formed on the recording paper 6. Similarly, by supplying two pulses of the ejection pulses DP1 and DP3 to the piezoelectric vibrator 16, a medium dot is formed, and three pulses of the ejection pulses DP1, DP2, and DP3 are supplied to the piezoelectric vibrator 16. Thus, a large dot is formed. Further, during non-recording when no dots are formed, the fine vibration DP4 is supplied to the piezoelectric vibrator 16, and the meniscus exposed to the nozzle opening 28 vibrates finely to the extent that ink droplets are not ejected. Here, the liquid amount (ejection liquid amount) and the flying speed of the ink droplets ejected by supplying the ejection pulses DP1 to DP3 depend on the shape of each ejection pulse and the driving voltage Vh (potential difference from the lowest potential to the highest potential). ). Therefore, the shape of each ejection pulse of the drive signal COM and the drive voltage Vh are set so that the target liquid amount (designed liquid amount) can be obtained on the average for the ink droplets ejected from all the nozzle openings 28. The drive signal COM is used in common for each actuator unit 13 mounted on the recording head 2.

  Next, the piezoelectric vibrator 16 will be described. As shown in FIG. 5, the piezoelectric vibrator 16 in the present embodiment is a stacked piezoelectric vibrator formed by alternately laminating a common internal electrode 55 and individual internal electrodes 56 with a piezoelectric body 57 interposed therebetween. is there. Here, the common internal electrode 55 is an electrode set to the same potential level with respect to all the piezoelectric vibrators 16. The individual internal electrode 56 is an electrode in which a potential level is set for each piezoelectric vibrator 16 in accordance with a supplied drive signal. In the present embodiment, a portion from the tip of the vibrator in the piezoelectric vibrator 16 to about two thirds of the vibrator longitudinal direction (direction perpendicular to the stacking direction) is defined as the free end portion 16a. The remaining portion of the piezoelectric vibrator 16, that is, the portion from the end of the free end portion 16a to the base end of the vibrator is used as a base end portion 16b.

  In the free end portion 16a, an active region (overlap portion) in which the common internal electrode 55 and the individual internal electrode 56 overlap each other is formed. When a potential difference is applied to these internal electrodes 55 and 56, the piezoelectric body 57 in the active region L is actuated and deformed, and the free end portion 16a is displaced in the longitudinal direction of the vibrator to expand and contract. The base end of the common internal electrode 55 is electrically connected to the common external electrode 58 at the base end surface portion of the piezoelectric vibrator 16. On the other hand, the tip of the individual internal electrode 56 is electrically connected to the individual external electrode 59 at the tip surface portion of the piezoelectric vibrator 16. Note that the distal end of the common internal electrode 55 is located slightly in front of the distal end surface portion of the vibrator of the piezoelectric vibrator 16, and the base end of the individual internal electrode 56 is the boundary between the free end portion 16a and the base end portion 16b. Is located.

  The individual external electrode 59 is an electrode formed in series on the tip surface portion of the piezoelectric vibrator 16 and a wiring connection surface (upper face in FIG. 5) which is one side surface of the piezoelectric vibrator 16 in the stacking direction. The wiring pattern of the cable 18 is electrically connected to each individual internal electrode 56. And the part by the side of the wiring connection surface of this separate external electrode 59 is continuously formed toward the front end side from the base end part 16b. The common external electrode 58 is formed on the base end surface portion of the piezoelectric vibrator 16, the above-described wiring connection surface, and a fixed plate mounting surface (lower surface in FIG. 5) which is the other side surface of the piezoelectric vibrator 16 in the stacking direction. It is an electrode formed in series, and conducts between the wiring pattern of the flexible cable 18 and each common internal electrode 55. The portion on the wiring connection surface side of the common external electrode 58 is continuously formed from slightly before the end portion of the individual external electrode 59 toward the base end surface portion side, and the portion on the fixed portion mounting surface side is It is continuously formed from a position slightly ahead of the distal end surface portion of the vibrator toward the proximal end side.

  These external electrodes 58 and 59 also function as electrodes for operating the outermost piezoelectric body 57. That is, the individual external electrode 59 is paired with the common internal electrode 55 across the piezoelectric body 57a formed on the outer surface in the stacking direction, and the common internal electrode 55 and the individual external electrode 59 are formed in the active region L. It overlaps. Accordingly, the portion of the active region L of the piezoelectric body 57a is deformed by the potential difference between the common internal electrode 55 and the individual external electrode 59. Similarly, the common external electrode 58 is paired with the individual internal electrode 56 across the piezoelectric body 57b formed on the outer surface in the stacking direction, and the individual internal electrode 56 and the common external electrode 58 are formed in the active region L. It overlaps. Therefore, the active region L of the piezoelectric body 57b is deformed by the potential difference between the individual internal electrode 56 and the common external electrode 58.

  The base end portion 16b is a non-operation portion that does not expand and contract even when the piezoelectric body 57 in the active region L is operated. A flexible cable 18 is arranged on the wiring connection surface side of the base end portion 16b, and the individual external electrode 59 and the common external electrode 58 and the flexible cable 18 are electrically connected on the base end portion 16b. A drive signal is supplied to each electrode through the flexible cable 18. Further, the fixing plate mounting surface of the base end portion 16b functions as a fixing plate joint, and the fixing plate 17 is joined. That is, each piezoelectric vibrator 16 is joined on the fixed plate 17 in a so-called cantilever state.

  Incidentally, as described above, the drive signal COM is used in common for each actuator unit 13, but ink droplets are ejected because there is an individual difference in the amount of displacement of the piezoelectric vibrator 16 with respect to the applied voltage (drive voltage). In some cases, the amount of liquid may vary from one actuator unit 13 to another. Therefore, in the manufacturing process of the printer 1, the actuator units 13 (piezoelectric vibrators 16) are arranged so that the characteristics of the actuator units 13 mounted on the recording head 2, that is, the displacement amounts of the piezoelectric vibrators 16 of the actuator units 13 are equal. ) And the combination of the actuator unit 13 based on the result of the characteristic inspection. Specifically, the amplitude of the back electromotive force signal generated by the residual vibration after expansion / contraction deformation of the piezoelectric vibrator 16 is measured, and the combination of the actuator units 13 mounted on the recording head 2 is determined based on the magnitude of the amplitude. To do. Hereinafter, this point will be described.

  FIG. 6 is a diagram for explaining an example of the configuration of an inspection apparatus used for the characteristic inspection of the actuator unit 13. As shown in the figure, the characteristic inspection uses an evaluation pulse generation circuit 61 that generates a measurement ejection pulse (evaluation pulse) and a back electromotive force amplitude measurement circuit 62 that functions as a back electromotive force amplitude measurement means. Do. In the present embodiment, the evaluation pulse generation circuit 61 and the recording head 2 are electrically connected, and the evaluation pulse generated by the evaluation pulse generation circuit 61 is supplied to the piezoelectric vibrator 16 to expand or contract the piezoelectric vibrator 16. Ink droplets are ejected from the recording head 2. Then, a back electromotive force signal based on the residual vibration after displacement of the piezoelectric vibrator 16 is output from the recording head 2 to the back electromotive force amplitude measuring circuit 62, and the back electromotive force amplitude measuring circuit 62 determines the amplitude of the back electromotive force signal. taking measurement.

  For example, the evaluation pulse generation circuit 61 generates an evaluation pulse TP1 shown in FIG. The evaluation pulse TP1 lowers the potential from the intermediate potential Vm to the ejection potential VD, thereby extending and displacing the piezoelectric vibrator 16 and ejecting ink droplets from the nozzle openings 28 (the displacement waveform element of the present invention). 1), a hold element P2 that is generated following the discharge element P1 and maintains the discharge potential VD for a certain period of time, and a damping element P3 that restores the potential from the discharge potential VD to the intermediate potential Vm. In other words, the evaluation pulse TP1 is an inspection signal including an ejection element as a displacement waveform element.

  The ejection element P1 is set to a voltage gradient that causes the pressure chamber 26 to contract and pressurize the ink in the pressure chamber. Further, the generation time Pw1 of the ejection element P1 is set to be, for example, ½ or less of the natural vibration period Tc. The hold element P <b> 2 is generated to hold the extended state of the piezoelectric vibrator 16. The amplitude of the back electromotive force signal is measured during the generation period of the hold element P2. Therefore, the generation time Pw2 of the hold element P2 is set to a time sufficient for measuring the amplitude of the back electromotive force signal, for example, about several times the period of the residual vibration of the piezoelectric vibrator 16. Here, if the piezoelectric vibrator 16 is unnecessarily expanded and contracted before the timing of checking the amplitude of the back electromotive force signal, vibrations excited each time are synthesized, and the waveform of the back electromotive force signal becomes complicated. This makes it difficult to accurately measure the amplitude of the back electromotive force signal. Therefore, in the evaluation pulse TP1 in the present embodiment, other waveform elements such as an expansion element that preliminarily expands the pressure chamber are not provided before the discharge element P1. The supply of the evaluation pulse TP1 is also performed in a state where the residual vibration at the previous drive has sufficiently converged.

  And a characteristic test | inspection passes through the following element drive processes and a back electromotive force amplitude measurement process. In the element driving step, the evaluation pulse TP1 is supplied to the piezoelectric vibrator 16 and the piezoelectric vibrator 16 is driven. At this time, the piezoelectric vibrator 16 expands due to the supply of the discharge element P1, and the pressure chamber 26 contracts accordingly. As a result, the ink in the pressure chamber is pressurized and ink droplets are ejected from the nozzle openings 28. Residual vibration is generated in the expanded piezoelectric vibrator 16. The residual vibration generates a counter electromotive force as shown in FIG. The counter electromotive force signal CF is output to the counter electromotive force amplitude measuring circuit 62.

  Next, in the back electromotive force amplitude measuring step, the back electromotive force amplitude measuring circuit 62 extracts the adjacent maximum value (waveform peak) and minimum value (waveform trough) of the back electromotive force signal CF (peak detection stage). ) The potential difference between the adjacent maximum value and minimum value detected in the peak detection stage is obtained as the amplitude of the back electromotive force signal CF (amplitude acquisition stage). In addition, the measurement of the amplitude is performed by the combination of the same maximum value and minimum value for all the actuator units 13. In the present embodiment, as shown in FIG. 8, the potential difference A between the second maximum value MX2 and the third maximum value MM3 after the residual vibration is excited, or the third maximum values MX3 and 3 The potential difference B between the second maximum value MM3 is obtained as the amplitudes A and B of the back electromotive force signal CF. The amplitude of the back electromotive force signal CF is larger at the initial stage and gradually converges with the passage of time. Therefore, in order to improve the measurement accuracy, the initial amplitude of the back electromotive force signal CF is measured as much as possible. It is desirable. Therefore, in the case of the amplitudes A and B, it is preferable to acquire the earlier amplitude A as the amplitude of the back electromotive force signal CF.

  As described above, when the amplitude of the back electromotive force signal CF is acquired, the combination process of the actuator unit 13 is performed. In this combination process, the combination of the actuator units 13 to be mounted on the recording head 2 is determined using the amplitude of the back electromotive force signal CF measured in the characteristic inspection as a reference (rank). That is, the actuator units 13 having the same rank are combined.

  FIG. 9 is a diagram showing the relationship between the displacement amount of the piezoelectric vibrator 16 (PZT) and the amplitude of the back electromotive force signal CF. In addition, the solid line graph in the figure shows the correlation when the amplitude A in FIG. 8 is measured, and the alternate long and short dash line graph shows the correlation when the amplitude B in FIG. 8 is measured. As shown in the figure, there is a correlation between the amount of displacement of the piezoelectric vibrator 16 and the amplitude of the back electromotive force signal CF. That is, the amplitude of the back electromotive force signal CF increases as the displacement amount of the piezoelectric vibrator 16 increases, and conversely, the amplitude of the back electromotive force signal CF decreases as the displacement amount of the piezoelectric vibrator 16 decreases. Therefore, in the combining step, the actuator units 13 having the same amplitude of the back electromotive force signal CF are combined. By mounting the actuator unit 13 combined in this way on the recording head 2, the displacement amount of each actuator unit 13 can be made equal. Thereby, even when ink droplets are ejected using a common drive signal COM in each actuator unit 13, the variation in the liquid amount can be reduced as much as possible. As a result, the image quality of the recorded image can be improved. It becomes possible to plan.

  In addition, this invention is not limited to above-described embodiment, A various deformation | transformation is possible based on description of a claim.

For example, regarding the evaluation pulse, in the above-described embodiment, the evaluation pulse TP1 having a configuration in which no other waveform element is arranged before the ejection element is illustrated. However, the present invention is not limited to this. For example, the evaluation pulse TP2 illustrated in FIG. As described above, it is possible to adopt a configuration having other waveform elements before the ejection elements. The evaluation pulse TP2 includes an expansion element Pa that increases the potential from the intermediate potential Vm to the maximum potential VH with a gradient that does not cause ink droplets to be ejected, and an expansion hold element Pb that connects the expansion element Pa and the ejection element P1 at the maximum potential VH. Are provided before the discharge element P1. That is, when the evaluation pulse T2 is supplied to the piezoelectric vibrator 16, the pressure vibrator 16 is first contracted by the expansion element Pa, whereby the pressure chamber 26 is expanded. As the pressure chamber 26 expands, ink flows from the reservoir 24 into the pressure chamber 26. The expansion state of the pressure chamber 26 is maintained over the generation time of the expansion hold element Pb. The generation time Pwb of the expansion hold element Pb is a time sufficient for the residual vibration generated by contracting and displacing the piezoelectric vibrator 16 by the expansion element Pa to converge (for example, the period of the residual vibration of the piezoelectric vibrator 16). 5 times or more). Then, after the residual vibration accompanying the contraction deformation of the piezoelectric vibrator 16 by the expansion element Pa is converged, the ejection element P1 is supplied to the piezoelectric vibrator 16 and the ink droplet is ejected, and the reverse based on the residual vibration at this time The amplitude of the electromotive force signal CF is measured. As a result, the amplitude of the back electromotive force signal CF can be accurately measured without being affected by other waveform elements arranged before the ejection element P1.
In short, as long as the evaluation pulse has a configuration in which the displacement waveform element is supplied to the piezoelectric vibrator 16 in a state where the residual vibration of the piezoelectric vibrator 16 at the time of previous driving has converged, one having various waveforms can be adopted. .

  In the above-described embodiment, the example of measuring the amplitude of the back electromotive force signal based on the residual vibration after the expansion of the piezoelectric vibrator 16 has been described. For example, based on the residual vibration after the piezoelectric vibrator 16 is contracted. It is also possible to measure the amplitude of the back electromotive force signal. In any case, it is not always necessary to eject ink droplets.

  Furthermore, in the above embodiment, the actuator unit 13 provided with a plurality of piezoelectric vibrators 16 as a unit is illustrated as the pressure generating means of the present invention. However, the present invention is not limited to this, and for example, for each pressure chamber individually A so-called flexural vibration mode piezoelectric vibrator provided may be employed as the pressure generating means of the present invention.

  The present invention can also be applied to liquid ejecting apparatuses other than the printer. For example, the present invention can be applied to a display manufacturing apparatus, an electrode manufacturing apparatus, a chip manufacturing apparatus, and the like.

FIG. 2 is a perspective view illustrating a configuration of a printer. FIG. 3 is a cross-sectional view of a main part illustrating the configuration of a recording head. 2 is a block diagram illustrating an electrical configuration of a printer. FIG. It is a figure explaining the structure of a drive signal. It is sectional drawing explaining the structure of a piezoelectric vibrator. It is a figure explaining an example of the composition of the device used for the characteristic inspection of an actuator unit. It is a wave form diagram explaining the structure of an evaluation pulse. It is a wave form diagram explaining the back electromotive force signal accompanying the residual vibration of a piezoelectric vibrator. It is a figure which shows the relationship between the displacement amount of a piezoelectric vibrator, and the amplitude of a back electromotive force signal. It is a wave form diagram explaining the structure of the modification of an evaluation pulse.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer, 2 Recording head, 4 Carriage, 13 Actuator unit, 14 Flow path unit, 16 Piezoelectric vibrator, 18 Flexible cable, 26 Pressure chamber, 28 Nozzle opening, 61 Evaluation pulse generation circuit, 62 Back electromotive force amplitude measurement circuit

Claims (6)

A liquid jet having a pressure chamber communicating with the nozzle opening and a plurality of pressure generating means capable of causing pressure fluctuation in the liquid in the pressure chamber, and discharging the liquid in the pressure chamber as droplets from the nozzle opening by the operation of the pressure generating means A method of manufacturing a liquid ejecting apparatus including a head,
An element driving step of supplying a displacement waveform element for displacing the pressure generating means to the pressure generating means to drive the pressure generating means;
Back electromotive force amplitude measuring step for measuring the amplitude of the back electromotive force signal based on the residual vibration of the pressure generating means generated after supplying the displacement waveform element;
And a combination step of determining a combination of pressure generating means mounted on the liquid ejecting head on the basis of the magnitude of the amplitude of the measured back electromotive force signal.   The manufacturing method according to claim 1, wherein in the counter electromotive force amplitude measuring step, an initial amplitude of the counter electromotive force signal is measured.   3. The manufacturing method according to claim 1, wherein in the combining step, the pressure generating means are combined so that the amplitudes of the back electromotive force signals are substantially equal.   The displacement driving element is supplied to the pressure generating means in a state where the residual vibration of the pressure generating means at the previous driving is converged in the element driving step. Production method.   The back electromotive force amplitude measuring step includes detecting a maximum value and a minimum value of the back electromotive force signal, and detecting a potential difference between the adjacent maximum value and the minimum value detected in the peak detection step. The manufacturing method according to any one of claims 1 to 4, further comprising: an amplitude obtaining step obtained as an amplitude of the above. A liquid ejecting apparatus comprising a liquid ejecting head on which pressure generating means combined by the manufacturing method according to claim 1 is mounted.

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