JP2005319707A - Inkjet apparatus and ink quality change detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet apparatus which can carry out optimum printing even when ink undergoes a quality change. <P>SOLUTION: Piezoelectric elements PZT1-PZTX set at many nozzle chambers of a head 20 are driven by driving amplifiers 38a-38x, respectively. An acoustic signal amplifier 42 is set at one piezoelectric element PZTX. At the time of measurement, a CPU 30 drives the piezoelectric element adjacent to the piezoelectric element PZTX without driving the piezoelectric element PZTX. The piezoelectric element PZTX receives its acoustic vibration and inputs an acoustic signal to the CPU 30 via the acoustic signal amplifier 42. The CPU 30 acquires correction data from the acoustic signal and corrects driving data by a driving waveform ROM 36. Each of the piezoelectric elements PZT1-PZTX of the nozzle head 20 is selectively driven by time series driving under an optimum driving condition of the corrected driving data, so that good ink discharging is enabled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink alteration detection device for detecting ink alteration in an ink jet device, and an ink jet device in which problems such as nozzle clogging due to ink alteration are less likely to occur.

  A piezoelectric inkjet recording apparatus uses piezoelectric system resonance to eject ink from a nozzle by a change in mechanical volume of an ink chamber (an ink chamber that is an ink reservoir immediately before the nozzle) in which the nozzle is formed. As an example, Patent Document 1 below discloses an example of an ink jet apparatus.

  This ink-jet apparatus is called a shear mode type. As shown in FIG. 2, the piezoelectric members 2 and 3 constituting the piezoelectric element laminated and bonded to the upper surface of one end of the elongated substrate 1, and the piezoelectric members 2 and 3, a plurality of long grooves 4, which are ink chambers having the same depth and length, and electrodes 5 formed on the side and bottom surfaces of the long groove 4, and the rear portion of the piezoelectric member 3 from the rear end of the long groove 4. An extraction electrode 6 formed on the upper end, a printed circuit board 7 bonded and fixed to the upper end of the other end of the substrate 1, a drive IC 8 with a built-in drive circuit mounted on the printed circuit board 7, and formed on the printed circuit board 7. The conductive pattern 9 connected to the drive IC 8, the conductive wire 10 joining the conductive pattern 9 and the extraction electrode 6, the top plate 12 that covers the upper surface of the piezoelectric member 3 with the insulating film 11, and the front surfaces of the piezoelectric members 2 and 3 And a nozzle plate 16 for closing.

  The insulating film 11 has ink inflow holes 13 communicating with every other long groove 4, and the top plate 12 has a common ink chamber 14 communicating with the holes 13. Ink is supplied to the ink chamber 14 from an ink supply unit (not shown). Similarly, the nozzle plate 16 has orifices 15 which are a plurality of nozzles communicating with every other long groove 4.

  As described above, the share mode type ink jet apparatus mechanically forms a large number of parallel long grooves 4 serving as ink chambers on a substrate material made of piezoelectric material, and these ink chambers communicate with each other in a common ink chamber 14. In other words, it has a structure in which adjacent ink chambers are partitioned with a common piezoelectric element as an actuator as a wall. When the voltage is applied during driving, the piezoelectric members 2 and 3 are deformed by receiving shear stresses in opposite directions, and the ink in the ink chamber between the two walls composed of the deformed piezoelectric elements is discharged from the nozzles. Discharged. Therefore, when a drive pulse is given at the time of driving and the piezoelectric element is deformed in the direction of decreasing the volume of the ink chamber and ink is ejected from the nozzle, it is possible to simultaneously decrease the volume of the adjacent ink chamber and simultaneously eject ink. Can not. Therefore, when driving a share mode type inkjet apparatus, adjacent ink chambers are not driven simultaneously, such as simultaneously ejecting ink from a line of nozzles arranged side by side. Usually, time series driving for driving the ink chamber is performed.

In the share mode type ink jet apparatus described in Patent Document 1, the long groove 4 communicating with the common ink chamber 14 as described above constitutes an ink chamber, and is adjacent to and communicates with the common ink chamber 14. The non-long groove 4 becomes a dummy ink chamber, and when the pressure of one ink chamber is increased and ink is ejected through the orifice 15, the timing of the drive pulse voltage applied so that the pressure of the other ink chamber decreases is shifted. Thus, the pressure variation of the common ink chamber 14 is small, and the variation of the ejection conditions in each ink chamber can be prevented as much as possible.
Patent No. 2931817

  By the way, the vibration factor using the above system resonance is composed of a piezoelectric element, a nozzle head structure (ink chamber) including the piezoelectric element, and ink in the ink chamber, and among them, environmental and physical variation factors. The relatively large material is ink.

Inks used for inkjet include water or petroleum-based solvents, colorants such as dyes or pigments, surfactants that reduce the surface tension of ink and promote penetration into recording materials, and organic solvents such as ethanol and isopropanol. It is composed of a penetrant, an anti-drying agent such as diethylene glycol, polyethylene glycol, glycerin, N-methyl-2-pyrodrin, etc. added to prevent the ink from drying and clogging the nozzles of the print head. For the ink containing a pigment, a pigment dispersant is added to aggregate the pigment and disperse the pigment.
By the way, in the ink containing the pigment, the aggregation of the pigment, the gel formation of the pigment dispersant added to disperse the pigment, the oxygen is dissolved in the ink, and the oxygen is discharged by the pressure applied by the nozzle, etc. Ink jet head nozzles were clogged, leading to a major cause of ejection failure. In addition, when the frequency of ink filling and printing is low, or when the non-printing state continues for a long time, the nozzle opening cannot be completely sealed. As a result, the viscosity of the ink in the ink rises and discharge failure occurs.

In general inkjet devices, fluctuation correction is performed especially for temperature based on the detection value of the temperature sensor, etc., but deterioration due to factors other than temperature, that is, aggregation of ink material as described above, change with time, etc. With respect to the alteration (physical property variation) of the ink itself as described above, there has conventionally been no means for feeding back data relating to the state and driving in the optimum mode suitable for the state.
Such a large change in physical properties of the ink leads to a shift in the driving conditions of the system, and as a result, causes a discharge failure of ink due to a driving error.

  The present invention solves the above-described problems, and detects the physical property variation (deterioration) of ink and corrects the driving condition for ejecting ink based on the detection result to obtain the optimal driving condition. An object of the present invention is to provide an ink jet apparatus.

  In order to achieve the above object, the present invention provides an inkjet apparatus that performs printing by ejecting ink droplets with a head in which a plurality of ink chambers each provided with a nozzle and a piezoelectric element are arranged in a row. Two adjacent ink chambers are appropriately determined from the elements, and these two piezoelectric elements are set as a piezoelectric element for an ink chamber that does not eject ink from a nozzle and a piezoelectric element for an ink chamber that ejects ink from a nozzle. The piezoelectric element of the ink chamber that sometimes does not eject ink is used as a vibration sensor (acoustic pickup), and the acoustic vibration generated when ink is ejected from the other ink chamber is detected and an acoustic signal is output. And the drive signal of the optimal condition measured in advance It is intended to leave. Then, the drive signal is corrected based on the comparison result so that optimum printing with few ejection defects can be performed.

The ink jet device according to claim 1 is connected to a head in which a plurality of ink chambers each provided with a nozzle and a piezoelectric element are arranged so as to communicate with each other, and to each piezoelectric element of each ink chamber. The plurality of drive amplifiers and the corresponding piezoelectric elements by selectively supplying drive signals to the respective drive amplifiers to eject ink from the respective nozzles of the corresponding ink chambers in time series. In a share mode type ink jet device provided with a control means,
Occurs when the second piezoelectric element of the second ink chamber connected to the first piezoelectric element of at least one first ink chamber arbitrarily selected from the plurality of ink chambers and adjacent to the first ink chamber is driven. An acoustic signal amplifier that receives acoustic vibrations and outputs an acoustic signal generated by the first piezoelectric element to the control means;
The control means gives a drive signal to the second piezoelectric element of the second ink chamber without giving a drive signal to the drive amplifier of the first ink chamber, and ejects ink from the nozzles of the second ink chamber. And the driving signal applied to the driving amplifier is corrected by the acoustic signal output from the acoustic signal amplifier.

  An ink jet apparatus according to a second aspect of the present invention is the ink jet apparatus according to the first aspect, wherein the control means includes storage means for storing drive data corresponding to a drive waveform for each drive condition, and the control means The correction data is obtained from the oscillation waveform of the acoustic signal generated by the first piezoelectric element when the second piezoelectric element is driven by the drive amplifier under a predetermined driving condition, and the driving waveform under the driving condition is obtained. This driving data is corrected by the correction data.

  The ink jet device according to claim 3 is the ink jet device according to claim 2, wherein the drive data of the drive waveform corresponding to a specific drive condition stored in the storage means and the drive data obtained under the same environmental condition are used. The control means performs a warning notification when the difference between the correction data changes more than a predetermined reference value.

  An ink jet apparatus according to a fourth aspect of the invention is the ink jet apparatus according to the first to third aspects, wherein the drive signal is supplied to the second piezoelectric element to eject ink from the nozzles of the second ink chamber, and The operation of correcting the drive signal with the acoustic signal generated by the first piezoelectric element is performed as an ink recovery operation in the ink jet apparatus.

  The inkjet device according to claim 5 is the inkjet device according to claims 1 to 3, wherein the drive signal is given to the second piezoelectric element to eject ink from the nozzles of the second ink chamber, and The operation of correcting the drive signal with the acoustic signal generated by the first piezoelectric element is performed as real-time feedback control during a printing operation in the ink jet apparatus.

According to a sixth aspect of the present invention, there is provided an ink alteration detection device comprising: a head in which a plurality of ink chambers each provided with a nozzle and a piezoelectric element are arranged so as to communicate with each other; and each piezoelectric element of each ink chamber. A plurality of drive amplifiers connected to each other, and selectively supplying a drive signal to each of the drive amplifiers to drive the corresponding piezoelectric elements to ink from the nozzles of the corresponding ink chambers in time series. Provided in a share mode type ink jet apparatus having a control means for discharging,
Occurs when the second piezoelectric element of the second ink chamber connected to the first piezoelectric element of at least one first ink chamber arbitrarily selected from the plurality of ink chambers and adjacent to the first ink chamber is driven. An acoustic signal amplifier that receives the acoustic vibration to be output and outputs an acoustic signal generated by the first piezoelectric element to the control means;
Storage means for storing a drive waveform of the piezoelectric element,
At the time of measurement, the control means gives a drive signal to the second piezoelectric element of the second ink chamber without giving a drive signal to the drive amplifier of the first ink chamber. A configuration for detecting ink alteration in the ink chamber by causing ink to be ejected from a nozzle and comparing the acoustic signal output from the acoustic signal amplifier with the drive waveform stored in the storage means. Is featured.

  According to the present invention, in a share mode type inkjet apparatus that performs time-series driving, a certain ink chamber does not eject ink from the nozzle, and an ink chamber adjacent to the ink chamber ejects ink from the nozzle. The acoustic vibration generated in the ink chamber can be detected by using an acoustic sensor (acoustic pickup) in the piezoelectric element of the adjacent ink chamber that does not eject ink, and an acoustic signal can be obtained. Even if no acoustic sensor is provided separately from the piezoelectric element, the physical change (degeneration) of ink can be detected easily and reliably by comparing this acoustic signal with the acoustic signal generated by ink ejection under the optimum conditions measured in advance. can do. In other words, the present invention utilizes the fact that there is a significant difference between the acoustic signal in the ink ejection under the optimum conditions and the acoustic signal in the case of ejection failure such as ejection or inability to eject the deteriorated ink. Abnormality can be detected to prevent printing errors in advance, or measures by other means can be taken.

  Then, based on the result of comparing this acoustic signal with the acoustic signal generated by the ink ejection under the optimum condition measured in advance, the optimum condition at the present time corresponding to the alteration of the ink is corrected by correcting the optimum ink ejection condition. Therefore, the ink jet apparatus can perform optimum printing with few ejection defects.

The best mode for carrying out the invention will be described below with reference to the accompanying drawings.
FIG. 1 is a circuit block diagram of an ink jet apparatus according to the present invention. In FIG. 1, the ink jet apparatus includes a nozzle head 20 and a circuit unit 22 for driving the nozzle head, as well as a paper feed mechanism (not shown) that is driven in synchronism with the nozzle head 20 and an ink recovery operation. Various other attachment mechanisms such as a nozzle cleaning mechanism are provided.

  The nozzle head 20 has a housing in which a plurality of ink chambers each having a nozzle are arranged, and piezoelectric elements (piezo elements) PZT1, PZT2, PZT3,... PZTX (PZTX: arbitrary) in each of these ink chambers. Ink ejection means provided with a piezoelectric element). In the nozzle head 20, if each piezoelectric element PZTX, the ink chamber provided with the piezoelectric element PZTX, and the ink filled in the ink chamber are considered to be elements having a predetermined impedance, these couplings are It can be regarded as an electrical equivalent circuit, and can be considered to constitute a vibration system having predetermined vibration characteristics.

  The nozzle head 20 of this example is a share mode ink type whose basic structure is described with reference to Patent Document 1 in the section of “Background Art”, that is, the ink chamber is configured by a long groove formed in a piezoelectric element. An opening at the tip of the long groove constitutes a nozzle. Therefore, the piezoelectric elements that divide the adjacent ink chambers are common to each other. In principle, each of the two adjacent ink chambers discharges ink by bringing the piezoelectric elements close to each other in the direction in which the volume of the ink chamber decreases. Ink cannot be ejected simultaneously from the nozzles. Accordingly, when the nozzle head 20 of this example is driven, adjacent ink chambers are not driven simultaneously, such as simultaneously ejecting ink from a row of nozzles arranged side by side, while being sequentially shifted in units of appropriate numbers. Time series driving for driving the ink chamber for one row is performed.

  This nozzle head 20 has different driving conditions for ejecting ink in the same manner due to subtle variations in machining at the time of manufacture. In order to correct this difference in driving conditions at the time of driving. The device 26 has the drive data written as the rank data in accordance with the variation of the manufacturing lot. Further, a temperature sensor 28 such as a thermistor is also arranged in order to cope with a change in behavior when ink is ejected due to a change in temperature. The device 26 and the temperature sensor 28 may be provided integrally with the nozzle head 20 or may be provided in the vicinity thereof. The rank data of the device 26 may be input to the circuit unit 22 from an operation panel (not shown) or the like as necessary.

  Each piezoelectric element PZTX is connected to an output side of a drive amplifier 38X, and an input side of each drive amplifier is connected to a CPU 30 as a control means so that a drive signal is inputted. When the CPU 30 selectively inputs a drive signal to each drive amplifier 38X, each piezoelectric element PZTX is selectively driven and ink is ejected from the nozzle of the corresponding ink chamber.

  The circuit unit 22 stores a CPU 30, RAM 32, a program ROM 34 as control means, a plurality of reference drive waveforms considering temperature correction suitable for the nozzle head 20 to be used, and drive data corresponding to each reference drive waveform in a table format. The drive waveform ROM 36 is provided and connected to the CPU 30. Further, the device 26 that supplies rank data due to variations in ink ejection and the temperature sensor 28 that provides temperature data are connected to the CPU 30. The CPU 30 extracts drive data from the drive waveform ROM 36 according to the data supplied from the device 26 and the temperature sensor 28, and passes through the drive amplifier 38 with a drive signal corresponding to this drive data according to the image data of the image to be printed. Thus, the piezoelectric elements PZT1, PZT2, PZT3,... PZTX of the nozzle head 20 can be selectively driven by time series driving.

  In this example, the input side of the acoustic signal amplifier 42 for measurement is connected to at least one piezoelectric element PZTX arbitrarily selected from the large number of piezoelectric elements PZTX, and the output side of the acoustic signal amplifier 42 Are connected to the CPU 30 via the A / D converter 44. That is, in this example, the specific piezoelectric element PZTX can also be used as a vibration sensor (acoustic pickup sensor). In this case, no drive signal is given to the piezoelectric element PZTX, and the piezoelectric element PZTX The acoustic vibration transmitted exclusively to the ink by the vibration of the adjacent piezoelectric element PZT (X-1) is received and an acoustic signal is output. The acoustic signal is amplified by the acoustic signal amplifier 42, A / D converted by the A / D converter 44, input to the CPU 30, and left to processing by the CPU 30 as will be described later.

Next, an operation during printing in the above configuration will be described.
When printing is executed, print data generated by a personal computer (not shown) connected to the apparatus is taken into the RAM 32. The CPU 30 takes in the temperature data detected by the temperature sensor 28 and the rank data written in the device 26, selects a driving waveform suitable for these data in the driving waveform ROM 36, and further corresponds to the selected driving waveform. The drive condition is called from the drive waveform ROM 36. Then, the CPU 30 executes the program stored in the program ROM 34 and sequentially takes out the print data temporarily stored in the RAM 32, while driving based on the optimum drive conditions according to the ink viscosity change and rank data accompanying the temperature change. A signal is generated and selectively output to each of the drive amplifiers 38a to 38x to selectively drive the piezoelectric elements PZT1, PZT2, PZT3,... PZTX of the nozzle head 20 by time series drive. In synchronization with this drive, the printing paper and the head move relative to each other, and ink droplets ejected from the head reach the printing paper, and an image corresponding to the print data is printed.

Next, a description will be given of the operation during measurement to detect ink alteration under a predetermined condition, correct the ink ejection driving condition according to the detected degree of alteration, and obtain the optimum ink ejection under the condition. To do.
In the control operation of the CPU 30 described below, the acoustic characteristics of the vibration system composed of the piezoelectric element, the ink chamber, and the ink are greatly influenced by changes in the physical properties of the ink. This is based on the knowledge that a significant difference occurs in the acoustic signal generated at the time of failure. That is, the CPU 30 measures the fact that the acoustic characteristics of the vibration system fluctuate due to the alteration of the ink, and measures the acoustic vibration when the ink is ejected by driving the piezoelectric element. And the driving condition of the piezoelectric element is corrected according to the degree of the variation. In this example, the detection of the ink alteration and the correction of the driving condition are performed at the time of the ink recovery operation performed when the nozzle clogging is suspected due to the printing defect or the like.

  First, during the ink recovery operation that is the timing of the acoustic characteristic measurement in this example, the CPU 30 does not drive the piezoelectric element PZTX to which the acoustic signal amplifier 42 is connected, and does not drive the adjacent piezoelectric element PZT (X-1). A drive signal is given and ink is ejected from the nozzle corresponding to the piezoelectric element PZT (X-1). This ink ejection is performed under driving conditions suitable for the temperature data from the temperature sensor 28 and the rank data of the device 26. However, the ink ejection is not always optimal due to the quality change of the ink.

  The acoustic vibration generated in the ink in the ink chamber by driving the piezoelectric element PZT (X-1) is transmitted to the ink in the adjacent ink chamber communicating with the ink chamber, and is received by the piezoelectric element PZTX in the ink chamber. The piezoelectric element PZTX outputs an acoustic signal corresponding to the received acoustic vibration. Then, the acoustic signal output from the piezoelectric element PZTX is amplified by the acoustic signal amplifier 42, converted into a digital signal by the A / D converter 44, and taken into the CPU 30.

  The CPU 30 analyzes the peak value and the frequency component from the acoustic signal to generate correction data, takes out the drive data from the drive waveform ROM 36 according to the data from the device 26 and the temperature sensor 28, and corrects the drive data to the correction signal. The data is corrected to obtain new drive data, which is stored at a predetermined position in the drive waveform ROM 36 to prepare for a subsequent printing operation. Therefore, in printing performed after measurement during the recovery operation, the CPU 30 uses the corrected drive data to match the temperature and the like under optimum driving conditions corresponding to the latest ink state. Each of the piezoelectric elements PZT1, PZT2, PZT3,... PZTX of the head 20 is selectively driven by time series driving, and printing can be performed under the most desirable conditions.

  In this example, the drive data is corrected with the correction data obtained from the acoustic signal from the piezoelectric element PZTX that is not driven, but the correction data is compared with the drive data, If there is a significant difference, it may be determined that the ink has been altered and the alteration of the ink may be detected based on this. For example, if the peak value of the correction data is within a predetermined range including the peak value of the drive data, it is determined that the ink has not deteriorated, and if it has deviated, the ink has deteriorated. to decide.

  The ink alteration detected as described above may be notified by outputting an alarm to the outside by some notifying means to stop the ink ejection operation. As the alarm output, for example, blinking of an error lamp provided in the apparatus, an error content on the display unit, or a display indicating that printing is impossible can be employed. With such an alarm output, the user can take various measures such as replacement of ink cartridges, which are other countermeasures, and contact support services.

  The detection of the ink alteration and the correction of the drive data based on the correction data described above are performed along with the ink recovery operation that is performed regularly or irregularly. For example, by setting a timer or the like built in the CPU 30 When the CPU 30 determines that the period from the previous printing execution to the current printing execution is long and corresponds to the deadline of ink deterioration, it is automatically executed regardless of the ink recovery operation when the apparatus is turned on. You may do it.

  Even within the time limit, if the user determines that the printed image quality is poor as a result of executing the printing, the user can individually execute it by a predetermined operation from the operation panel or the like. It may be.

  At the time of correction of drive data performed when ink alteration is detected, one or more nozzles configured by the piezoelectric elements PZT1, PZT2, PZT3,... PZTX of the nozzle head 20 are actually driven and printed. Since ink is ejected in the same manner as at the time, it is assumed that the ejected ink is received by the printing paper or by an ink collection container or the like used during the ink recovery operation.

1 is a circuit block diagram of an inkjet apparatus according to the present invention. It is a disassembled perspective view which shows the nozzle head of the conventional inkjet apparatus.

Explanation of symbols

20 nozzle head 22 circuit unit PZT1 to PZTX piezoelectric element 30 CPU as control means
36 Drive waveform ROM (drive waveform and drive data storage means corresponding thereto)
38 Drive amplifier 42 Acoustic signal amplifier

Claims (6)

A plurality of ink chambers each provided with a nozzle and a piezoelectric element are arranged in a row so as to communicate with each other, a plurality of drive amplifiers connected to each piezoelectric element of each ink chamber, and each drive A share mode type ink jet comprising a control means for driving each of the corresponding piezoelectric elements by selectively supplying a drive signal to an amplifier and ejecting ink from each of the nozzles of the corresponding ink chamber in time series In the device
Occurs when the second piezoelectric element of the second ink chamber connected to the first piezoelectric element of at least one first ink chamber arbitrarily selected from the plurality of ink chambers and adjacent to the first ink chamber is driven. An acoustic signal amplifier that receives acoustic vibrations and outputs an acoustic signal generated by the first piezoelectric element to the control means;
The control means gives a drive signal to the second piezoelectric element of the second ink chamber without giving a drive signal to the drive amplifier of the first ink chamber, and ejects ink from the nozzles of the second ink chamber. And an acoustic signal output from the acoustic signal amplifier is used to correct a drive signal applied to the drive amplifier. The control means includes
Having storage means for storing drive data corresponding to the drive waveform for each drive condition;
The correction data is obtained from the oscillation waveform of the acoustic signal generated by the first piezoelectric element when the second piezoelectric element is driven by the drive amplifier under a predetermined driving condition, and the driving waveform is driven under the driving condition. 2. The ink jet apparatus according to claim 1, wherein the data is corrected by the correction data. The control means when the difference between the drive data of the drive waveform corresponding to a specific drive condition stored in the storage means and the correction data obtained under the same environmental condition changes more than a predetermined reference value 3. The ink jet apparatus according to claim 2, wherein warning notification is performed. The operation of applying the drive signal to the second piezoelectric element to eject ink from the nozzle of the second ink chamber and correcting the drive signal with the acoustic signal generated by the first piezoelectric element is performed by the inkjet The inkjet apparatus according to claim 1, wherein the inkjet apparatus is performed as an ink recovery operation in the apparatus. The operation of applying the drive signal to the second piezoelectric element to eject ink from the nozzle of the second ink chamber and correcting the drive signal with the acoustic signal generated by the first piezoelectric element is performed by the inkjet The ink jet apparatus according to claim 1, wherein the ink jet apparatus is performed as real time feedback control during a printing operation in the apparatus. A plurality of ink chambers each provided with a nozzle and a piezoelectric element are arranged in a row so as to communicate with each other, a plurality of drive amplifiers connected to each piezoelectric element of each ink chamber, and each drive A share mode type ink jet comprising control means for driving the corresponding piezoelectric elements by selectively supplying a drive signal to an amplifier to eject ink from the nozzles of the corresponding ink chambers in time series. Provided in the device,
Occurs when the second piezoelectric element of the second ink chamber connected to the first piezoelectric element of at least one first ink chamber arbitrarily selected from the plurality of ink chambers and adjacent to the first ink chamber is driven. An acoustic signal amplifier that receives the acoustic vibration to be output and outputs an acoustic signal generated by the first piezoelectric element to the control means;
Storage means for storing a drive waveform of the piezoelectric element,
The control means provides a drive signal to the second piezoelectric element of the second ink chamber without giving a drive signal to the drive amplifier of the first ink chamber at the time of measurement. A configuration for detecting ink alteration in the ink chamber by causing ink to be ejected from a nozzle and comparing the acoustic signal output from the acoustic signal amplifier with the drive waveform stored in the storage means. An ink alteration detection device comprising:

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