JP4240077B2 - Liquid consumption state detection method - Google Patents

Description

  The present invention detects a change in acoustic impedance, and in particular, a piezoelectric device for detecting a consumption state of a liquid in a liquid container containing a liquid such as ink by detecting a change in resonance frequency (among others) The present invention relates to a liquid container provided with an actuator. More specifically, the present invention relates to an ink cartridge suitable for an ink jet recording apparatus that pressurizes ink in a pressure generation chamber in accordance with print data by a pressure generation unit and ejects ink droplets from nozzle openings to perform printing.

  As an example of the liquid container, an ink cartridge used in an ink jet recording apparatus that prints by ejecting ink droplets from nozzle openings will be described below. An ink jet recording apparatus mounts an ink jet recording head including pressure generating means for pressurizing a pressure generating chamber and a nozzle opening for ejecting pressurized ink as ink droplets from the nozzle opening on a carriage. The ink jet recording apparatus is configured to be able to continue printing while supplying ink from an ink tank to a recording head via a flow path. The ink tank is configured as a detachable cartridge so that the user can easily replace it when the ink is consumed.

  Conventionally, as a method for managing ink consumption of an ink cartridge, the number of ink droplets discharged from a recording head and the amount of ink sucked by maintenance are integrated by software, and the ink consumption is managed by calculation. There is a method of managing a point in time when a predetermined amount of ink is actually consumed by attaching a surface detection electrode.

  However, in the method of calculating and managing the ink consumption by integrating the number of ink droplets discharged and the amount of ink by software, an error occurs depending on the printing form on the user side, or a large error occurs when the same cartridge is remounted. There is a problem. Also, depending on the usage environment, the pressure in the ink cartridge and the viscosity of the ink change depending on the room temperature, for example, extremely high or low, or the elapsed time after opening the ink cartridge, and the calculated ink consumption and actual consumption There was also a problem that an error that could not be ignored occurred. On the other hand, the method for managing the point in time when ink is consumed by the electrode can detect the actual amount of ink, so that the remaining amount of ink can be managed with high reliability. However, since the detection of the ink level depends on the conductivity of the ink, there are problems that the types of ink that can be detected are limited and the electrode seal structure is complicated. In addition, since a noble metal having high conductivity and high corrosion resistance is usually used as the electrode material, there is a problem that the manufacturing cost of the ink cartridge is increased. Furthermore, since it is necessary to mount two electrodes, there is a problem that the manufacturing process increases and as a result, the manufacturing cost increases.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid consumption state detection method and a liquid container that can accurately detect the remaining amount of liquid and that do not require a complicated seal structure. And Still another object is to provide a stable detection method that is not affected by an unstable measurement signal that occurs in the early stage of measuring the liquid consumption state. Still another object is to provide a detection method capable of shortening the time for detecting the liquid consumption state. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.

  The present invention is a liquid consumption state detection method for detecting a liquid consumption state in the liquid container by detecting residual vibration generated in the piezoelectric device mounted on the liquid container, and after driving the piezoelectric device, The consumption state of the liquid is measured by detecting the frequency of the residual vibration after a predetermined interval.

  Preferably, the consumption state of the liquid in the liquid container is detected by detecting the frequency of residual vibration generated in the piezoelectric device.

  Preferably, the piezoelectric device detects a liquid consumption state in the liquid container by detecting a resonance frequency of the liquid around the device.

  Preferably, after the piezoelectric device is driven, the consumption state of the liquid is detected after the piezoelectric device vibrates several times.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency between approximately 100 kHz and 600 kHz.

  Preferably, the frequency of the residual vibration is calculated by measuring the time between predetermined peaks of the residual vibration of the piezoelectric device, and the consumption state is detected using the frequency.

  Preferably, the frequency of the residual vibration is calculated by measuring the number of peaks of the residual vibration of the piezoelectric device within a predetermined time, and the consumption state is detected using the frequency.

  Preferably, the consumption state of the liquid is detected by measuring the voltage level of the counter electromotive force generated by the residual vibration of the piezoelectric device.

  Preferably, the measurement value of the vibration frequency of the residual vibration in the process in which the liquid in the liquid container is consumed is set to the reference value of the measurement value of the vibration frequency of the residual vibration when the liquid in the liquid container is full. The consumption state of the liquid is determined by comparison.

  Preferably, vibration frequencies of a plurality of resonance modes of residual vibration of the piezoelectric device are detected.

  Preferably, the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode are detected by detecting the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode of the residual vibration of the piezoelectric device. The frequency is recognized as one pattern.

  Preferably, the piezoelectric device oscillates itself, and the consumption state of the liquid in the liquid container is detected by detecting residual vibration caused by the oscillation.

  Preferably, the liquid container is an ink cartridge used in an ink jet recording apparatus.

  In the liquid consumption state detection method according to the first aspect of the present invention, the piezoelectric device mounted on the liquid container is driven, and the frequency of the residual vibration generated by driving the piezoelectric device is detected, so that the liquid in the liquid container is detected. This is a liquid consumption state detection method for detecting a consumption state. It is preferable to detect the consumption state of the liquid in the liquid container by detecting the frequency of the residual vibration generated by the oscillation of the piezoelectric device itself. Moreover, it is preferable that the piezoelectric device detects the liquid consumption state in the liquid container by detecting the resonance frequency of the liquid around the device. Furthermore, it is preferable to measure the liquid consumption state by detecting the frequency of the residual vibration after a predetermined interval after driving the piezoelectric device.

  It is preferable to detect the liquid consumption state after the piezoelectric device is driven and after the piezoelectric device vibrates several times. Moreover, it is preferable that the vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region. Furthermore, it is preferable that the vibration frequency at which the piezoelectric device vibrates is a frequency between approximately 100 kHz and 600 kHz. The frequency of the residual vibration may be calculated by measuring the time between predetermined peaks of the residual vibration of the piezoelectric device, and the consumption state may be detected using the frequency. Alternatively, the frequency of residual vibration may be calculated by measuring the number of peaks of residual vibration of the piezoelectric device within a predetermined time, and the consumption state may be detected using the frequency. The liquid consumption state may be detected by measuring the voltage level of the counter electromotive force generated by the residual vibration of the piezoelectric device.

  Also, using the measurement value of the vibration frequency of the residual vibration when the liquid in the liquid container is full as a reference value, compare the measurement value of the vibration frequency of the residual vibration in the process in which the liquid in the liquid container is consumed. It is preferable to determine the consumption state of the liquid.

  It is preferable to detect vibration frequencies of a plurality of resonance modes of residual vibration of the piezoelectric device. In addition, the vibration frequency of the first resonance mode and the second resonance mode of the residual vibration of the piezoelectric device is detected, and the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode are recognized as one pattern. It is preferable to do. The liquid container is preferably an ink cartridge used in an ink jet recording apparatus.

  The liquid container according to the second aspect of the present invention is a liquid container that contains a liquid, and includes a piezoelectric device that detects a liquid consumption state by generating a back electromotive force due to residual vibration remaining after oscillation. Is preferred. Furthermore, it is preferable that the piezoelectric device oscillates itself and detects the frequency of residual vibration caused by the oscillation. Furthermore, it is preferable that the piezoelectric device detects the resonance frequency of the liquid around the device. The piezoelectric device preferably vibrates in at least one resonance mode. Preferably, the vibration in at least one resonance mode is greater than the vibration in the other resonance mode. Furthermore, it is preferable that the vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region. Furthermore, it is preferable that the vibration frequency at which the piezoelectric device vibrates is a frequency between approximately 100 kHz and 600 kHz. Furthermore, it is preferable that the liquid container is an ink cartridge that contains a recording liquid to be supplied to the ink jet recording apparatus.

  The present invention is preferably a liquid consumption state detection method for detecting a liquid consumption state in the liquid container by detecting a residual vibration generated in the piezoelectric device mounted on the liquid container.

  Preferably, the consumption state of the liquid in the liquid container is detected by detecting the frequency of residual vibration generated in the piezoelectric device.

  Preferably, the piezoelectric device detects a liquid consumption state in the liquid container by detecting a resonance frequency of the liquid around the device.

  Preferably, after the piezoelectric device is driven, the consumption state of the liquid is measured by detecting the frequency of the residual vibration after a predetermined interval.

  Preferably, after the piezoelectric device is driven, the consumption state of the liquid is detected after the piezoelectric device vibrates several times.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency between approximately 100 kHz and 600 kHz.

  Preferably, the frequency of the residual vibration is calculated by measuring the time between predetermined peaks of the residual vibration of the piezoelectric device, and the consumption state is detected using the frequency.

  Preferably, the frequency of the residual vibration is calculated by measuring the number of peaks of the residual vibration of the piezoelectric device within a predetermined time, and the consumption state is detected using the frequency.

  Preferably, the consumption state of the liquid is detected by measuring the voltage level of the counter electromotive force generated by the residual vibration of the piezoelectric device.

  Preferably, the measurement value of the vibration frequency of the residual vibration in the process in which the liquid in the liquid container is consumed is set to the reference value of the measurement value of the vibration frequency of the residual vibration when the liquid in the liquid container is full. The consumption state of the liquid is determined by comparison.

  Preferably, vibration frequencies of a plurality of resonance modes of residual vibration of the piezoelectric device are detected.

  Preferably, the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode are detected by detecting the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode of the residual vibration of the piezoelectric device. The frequency is recognized as one pattern.

  Preferably, the piezoelectric device oscillates itself, and the consumption state of the liquid in the liquid container is detected by detecting residual vibration caused by the oscillation.

  In the invention, it is preferable that the liquid container is an ink cartridge used in an ink jet recording apparatus.

  The present invention is preferably a liquid container that contains a liquid, and includes a piezoelectric device that detects a consumption state of the liquid by detecting residual vibration.

  Preferably, the piezoelectric device detects a frequency of residual vibration.

  Preferably, the piezoelectric device detects a resonance frequency of liquid around the device.

  Preferably, the piezoelectric device vibrates in at least one resonance mode.

  Preferably, the vibration in at least one resonance mode is greater than the vibration in other resonance modes.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region.

  Preferably, the vibration frequency at which the piezoelectric device vibrates is a frequency between approximately 100 kHz and 600 kHz.

  Preferably, the piezoelectric device oscillates itself and detects residual vibration caused by the oscillation.

  The present invention is preferably an ink cartridge characterized in that a recording liquid supplied to an ink jet recording apparatus is contained in the liquid container.

  The piezoelectric device, module body, liquid container, and ink cartridge of the present invention can accurately detect the remaining amount of liquid and do not require a complicated seal structure. Furthermore, the piezoelectric device, the module body, the liquid container, and the ink cartridge of the present invention can be manufactured at low cost and have good mountability to the liquid container.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are the solution of the invention. It is not always essential to the means.

  The basic concept of the present invention is to use the vibration phenomenon to determine the state of the liquid in the liquid container (including the presence or absence of the liquid in the liquid container, the amount of the liquid, the level of the liquid, the type of the liquid, and the composition of the liquid). Is to detect. Several methods are conceivable for detecting the state of the liquid in the liquid container using a specific vibration phenomenon. For example, the elastic wave generating means generates an elastic wave to the inside of the liquid container, and receives a reflected wave reflected by the liquid surface or an opposing wall, thereby detecting a medium in the liquid container and a change in the state thereof. There is a way. In addition, there is a method for detecting a change in acoustic impedance from the vibration characteristics of a vibrating object. As a method of using a change in acoustic impedance, a vibration part of a piezoelectric device or an actuator having a piezoelectric element is vibrated, and then a counter electromotive force generated by residual vibration remaining in the vibration part is measured, whereby a resonance frequency or an inverse is obtained. A method for detecting a change in acoustic impedance by detecting the amplitude of an electromotive force waveform, or measuring a liquid impedance characteristic or an admittance characteristic with an impedance analyzer such as a measuring machine, for example, a transmission circuit, and a change in current value or voltage value or There is a method of measuring a change in current value or voltage value depending on the frequency when vibration is applied to a liquid. The details of the operation principle of the piezoelectric device or actuator will be described below.

  1 and 2 show details and an equivalent circuit of an actuator 106 that is an embodiment of the piezoelectric device. The actuator here is used in a method of detecting a consumption state of a liquid in a liquid container by detecting at least a change in acoustic impedance. In particular, the present invention is used in a method of detecting a consumption state of liquid in a liquid container by detecting at least a change in acoustic impedance by detecting a resonance frequency by residual vibration. FIG. 1A is an enlarged plan view of the actuator 106. FIG. 1B shows a BB cross section of the actuator 106. FIG. 1C shows a CC cross section of the actuator 106. 2A and 2B show an equivalent circuit of the actuator 106. FIG. FIGS. 2C and 2D show the periphery including the actuator 106 and its equivalent circuit when the ink is filled in the ink cartridge, respectively, and FIGS. 2E and 2F. ) Shows the periphery including the actuator 106 and its equivalent circuit when there is no ink in the ink cartridge.

  The actuator 106 includes a substrate 178 having a circular opening 161 at substantially the center, a vibration plate 176 disposed on one surface (hereinafter referred to as a surface) of the substrate 178 so as to cover the opening 161, and the vibration plate 176. The piezoelectric layer 160 disposed on the surface side, the upper electrode 164 and the lower electrode 166 sandwiching the piezoelectric layer 160 from both sides, the upper electrode terminal 168 electrically coupled to the upper electrode 164, and the lower electrode 166 electrically A lower electrode terminal 170 to be coupled and an auxiliary electrode 172 disposed between the upper electrode 164 and the upper electrode terminal 168 and electrically coupled to each other are provided. The piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 each have a circular portion as a main part. Each circular portion of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 forms a piezoelectric element.

  The diaphragm 176 is formed on the surface of the substrate 178 so as to cover the opening 161. The cavity 162 is formed by a portion facing the opening 161 of the diaphragm 176 and the opening 161 on the surface of the substrate 178. The surface of the substrate 178 opposite to the piezoelectric element (hereinafter referred to as the back surface) faces the liquid container side, and the cavity 162 is configured to come into contact with the liquid. The diaphragm 176 is liquid-tightly attached to the substrate 178 so that the liquid does not leak to the surface side of the substrate 178 even if the liquid enters the cavity 162.

  The lower electrode 166 is located on the surface of the vibration plate 176, that is, the surface opposite to the liquid container, and is attached so that the center of the circular portion which is the main part of the lower electrode 166 and the center of the opening 161 are substantially coincided with each other. It has been. The area of the circular portion of the lower electrode 166 is set to be smaller than the area of the opening 161. On the other hand, on the surface side of the lower electrode 166, the piezoelectric layer 160 is formed so that the center of the circular portion and the center of the opening 161 substantially coincide. The area of the circular portion of the piezoelectric layer 160 is set to be smaller than the area of the opening 161 and larger than the area of the circular portion of the lower electrode 166.

  On the other hand, on the surface side of the piezoelectric layer 160, the upper electrode 164 is formed so that the center of the circular portion which is the main part thereof substantially coincides with the center of the opening 161. The area of the circular part of the upper electrode 164 is set to be smaller than the area of the circular part of the opening 161 and the piezoelectric layer 160 and larger than the area of the circular part of the lower electrode 166.

  Therefore, the main part of the piezoelectric layer 160 is structured to be sandwiched between the main part of the upper electrode 164 and the main part of the lower electrode 166 from the front surface side and the back surface side, respectively. Deformation drive is possible. The circular portions that are the main portions of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 form a piezoelectric element in the actuator 106. As described above, the piezoelectric element is in contact with the diaphragm 176. Of the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, the circular portion of the lower electrode 166, and the opening 161, the opening 161 has the largest area. With this structure, the vibration region of the diaphragm 176 that actually vibrates is determined by the opening 161. Further, since the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, and the circular portion of the lower electrode 166 have a smaller area than the opening 161, the diaphragm 176 is more likely to vibrate. Furthermore, of the circular portion of the lower electrode 166 and the circular portion of the upper electrode 164 that are electrically connected to the piezoelectric layer 160, the circular portion of the lower electrode 166 is smaller. Accordingly, the circular portion of the lower electrode 166 determines the portion of the piezoelectric layer 160 that generates the piezoelectric effect.

  Therefore, the main part of the piezoelectric layer 160 is structured to be sandwiched between the main part of the upper electrode 164 and the main part of the lower electrode 166 from the front surface side and the back surface side, respectively. Deformation drive is possible. The circular portions that are the main portions of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 form a piezoelectric element in the actuator 106. As described above, the piezoelectric element is in contact with the diaphragm 176. Of the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, the circular portion of the lower electrode 166, and the opening 161, the opening 161 has the largest area. With this structure, the vibration region of the diaphragm 176 that actually vibrates is determined by the opening 161. Further, since the circular portion of the upper electrode 164, the circular portion of the piezoelectric layer 160, and the circular portion of the lower electrode 166 have a smaller area than the opening 161, the diaphragm 176 is more likely to vibrate. Furthermore, of the circular portion of the lower electrode 166 and the circular portion of the upper electrode 164 that are electrically connected to the piezoelectric layer 160, the circular portion of the lower electrode 166 is smaller. Accordingly, the circular portion of the lower terminal 166 determines the portion of the piezoelectric layer 160 that generates the piezoelectric effect.

  The centers of the circular portions of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 that form the piezoelectric element substantially coincide with the center of the opening 161. In addition, the center of the circular opening 161 that determines the vibrating portion of the diaphragm 176 is provided substantially at the center of the actuator 106. Therefore, the center of the vibration part of the actuator 106 substantially coincides with the center of the actuator. Further, since the main part of the piezoelectric element and the vibration part of the vibration plate 176 have a circular shape, the vibration part of the actuator 106 has a symmetrical shape with respect to the center of the actuator 106.

  Since the vibration part has a symmetrical shape with respect to the center of the actuator 106, it is possible to prevent excitation of unnecessary vibration caused by the asymmetry of the structure. Therefore, the detection accuracy of the resonance frequency is improved. Furthermore, since the vibration part has a symmetrical shape with respect to the center of the actuator, it is easy to manufacture, and variation in the shape of each piezoelectric element can be reduced. Therefore, the variation in the resonance frequency for each piezoelectric element is reduced. In addition, since the vibration part has an isotropic shape, it is less susceptible to variations in fixation during bonding. Evenly adhered to the liquid container. Therefore, the mountability of the actuator 106 to the liquid container is good.

  Furthermore, since the vibration part of the diaphragm 176 has a circular shape, in the resonance mode of the residual vibration of the piezoelectric layer 160, a low-order, for example, primary resonance mode becomes dominant, and a single peak appears. Therefore, since the peak and the noise can be clearly distinguished, the resonance frequency can be clearly detected. In addition, by increasing the area of the vibrating portion of the circular diaphragm 176, the difference between the amplitude of the back electromotive force waveform and the resonance frequency due to the presence or absence of liquid increases, further improving the accuracy of detection of the resonance frequency. it can.

  The displacement due to the vibration of the diaphragm 176 is much larger than the displacement due to the vibration of the substrate 178. The actuator 106 has a two-layer structure of a substrate 178 having a small compliance, that is, not easily displaced by vibration, and a diaphragm 176 having a large compliance, that is, easily displaced by vibration. With this two-layer structure, the displacement of the diaphragm 176 due to vibration can be increased while being securely fixed to the liquid container by the substrate 178, and therefore the difference between the amplitude of the back electromotive force waveform and the resonance frequency due to the presence or absence of liquid is large. Thus, the accuracy of detecting the resonance frequency can be improved. Furthermore, since the compliance of the diaphragm 176 is large, the attenuation of vibration is reduced, and the accuracy of detecting the resonance frequency can be improved. The vibration node of the actuator 106 is located in the outer peripheral portion of the cavity 162, that is, near the edge of the opening 161.

  The upper electrode terminal 168 is formed on the surface side of the diaphragm 176 so as to be electrically connected to the upper electrode 164 through the auxiliary electrode 172. On the other hand, the lower electrode terminal 170 is formed on the surface side of the diaphragm 176 so as to be electrically connected to the lower electrode 166. Since the upper electrode 164 is formed on the surface side of the piezoelectric layer 160, it is necessary to have a step equal to the sum of the thickness of the piezoelectric layer 160 and the thickness of the lower electrode 166 in the middle of connection with the upper electrode terminal 168. It is difficult to form the step with only the upper electrode 164, and even if possible, the connection state between the upper electrode 164 and the upper electrode terminal 168 becomes weak and there is a risk of disconnection. Therefore, the upper electrode 164 and the upper electrode terminal 168 are connected using the auxiliary electrode 172 as an auxiliary member. By doing so, the piezoelectric layer 160 and the upper electrode 164 are both supported by the auxiliary electrode 172, and a desired mechanical strength can be obtained, and the connection between the upper electrode 164 and the upper electrode terminal 168 is ensured. It becomes possible to.

  The vibration region facing the piezoelectric element in the piezoelectric element and the diaphragm 176 is a vibration part that actually vibrates in the actuator 106. Moreover, it is preferable that the members included in the actuator 106 are integrally formed by firing each other. By integrally forming the actuator 106, the handling of the actuator 106 becomes easy. Furthermore, the vibration characteristics are improved by increasing the strength of the substrate 178. That is, by increasing the strength of the substrate 178, only the vibration portion of the actuator 106 vibrates, and portions other than the vibration portion of the actuator 106 do not vibrate. Further, in order not to vibrate parts other than the vibration part of the actuator 106, the strength of the substrate 178 can be increased, whereas the piezoelectric element of the actuator 106 is made thin and small and the vibration plate 176 is made thin.

  As the material of the piezoelectric layer 160, it is preferable to use lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), or lead-free piezoelectric film that does not use lead, and the substrate 178 is made of zirconia or alumina. It is preferable to use it. Further, it is preferable to use the same material as the substrate 178 for the diaphragm 176. For the upper electrode 164, the lower electrode 166, the upper electrode terminal 168, and the lower electrode terminal 170, a conductive material, for example, a metal such as gold, silver, copper, platinum, aluminum, or nickel can be used.

  The actuator 106 configured as described above can be applied to a container that contains a liquid. For example, the ink cartridge can be attached to an ink cartridge or an ink tank used in an ink jet recording apparatus, or a container containing a cleaning liquid for cleaning the recording head.

  The actuator 106 shown in FIGS. 1 and 2 is mounted at a predetermined location of the liquid container so that the cavity 162 is in contact with the liquid contained in the liquid container. When the liquid is sufficiently stored in the liquid container, the inside of the cavity 162 and the outside thereof are filled with the liquid. On the other hand, when the liquid in the liquid container is consumed and the liquid level drops below the mounting position of the actuator, there is no liquid in the cavity 162, or liquid remains only in the cavity 162 and there is gas outside the cavity 162. It becomes a state to do. The actuator 106 detects at least a difference in acoustic impedance caused by the change in the state. Accordingly, the actuator 106 can detect whether the liquid is sufficiently contained in the liquid container or whether a certain amount of liquid is consumed. Furthermore, the actuator 106 can also detect the type of liquid in the liquid container.

  Here, the principle of the liquid level detection by the actuator will be described.

  In order to detect a change in the acoustic impedance of the medium, the impedance characteristic or admittance characteristic of the medium is measured. When measuring impedance characteristics or admittance characteristics, for example, a transmission circuit can be used. The transmission circuit applies a constant voltage to the medium, changes the frequency, and measures the current flowing through the medium. Alternatively, the transmission circuit supplies a constant current to the medium and changes the frequency to measure the voltage applied to the medium. A change in current value or voltage value measured in the transmission circuit indicates a change in acoustic impedance. In addition, a change in the frequency fm at which the current value or voltage value becomes maximum or minimum also indicates a change in acoustic impedance.

  Apart from the above method, the actuator can detect the change in the acoustic impedance of the liquid using the change only in the resonance frequency. When using the method of detecting the resonance frequency by measuring the counter electromotive force generated by the residual vibration remaining in the vibration part after the vibration part of the actuator vibrates as a method using the change in the acoustic impedance of the liquid, for example, A piezoelectric element can be used. The piezoelectric element is an element that generates a counter electromotive force due to residual vibration remaining in the vibration part of the actuator, and the magnitude of the counter electromotive force changes depending on the amplitude of the vibration part of the actuator. Therefore, detection is easier as the amplitude of the vibration part of the actuator is larger. In addition, the period in which the magnitude of the back electromotive force changes depends on the frequency of residual vibration in the vibration part of the actuator. Therefore, the frequency of the vibration part of the actuator corresponds to the frequency of the counter electromotive force. Here, the resonance frequency is a frequency in a resonance state between the vibration part of the actuator and the medium in contact with the vibration part.

  In order to obtain the resonance frequency fs, the waveform obtained by the back electromotive force measurement when the vibration part and the medium are in the resonance state is Fourier-transformed. The vibration of the actuator is not only deformed in one direction but is accompanied by various deformations such as deflection and extension, and therefore has various frequencies including the resonance frequency fs. Therefore, the resonance frequency fs is determined by Fourier-transforming the back electromotive force waveform when the piezoelectric element and the medium are in the resonance state and specifying the most dominant frequency component.

  The frequency fm is a frequency when the admittance of the medium is maximum or the impedance is minimum. Assuming the resonance frequency fs, the frequency fm causes a slight error with respect to the resonance frequency fs due to dielectric loss or mechanical loss of the medium. However, since it takes time to derive the resonance frequency fs from the actually measured frequency fm, the frequency fm is generally used instead of the resonance frequency. Here, by inputting the output of the actuator 106 to the transmission circuit, the actuator 106 can detect at least the acoustic impedance.

  A resonance frequency specified by a method for measuring the frequency fm by measuring the impedance characteristic or admittance characteristic of the medium, and a method for measuring the resonance frequency fs by measuring the counter electromotive force generated by the residual vibration in the vibration part of the actuator. It has been proved by experiments that there is almost no difference between the two.

  The vibration region of the actuator 106 is a part constituting the cavity 162 determined by the opening 161 of the vibration plate 176. When the liquid is sufficiently stored in the liquid container, the cavity 162 is filled with the liquid, and the vibration region comes into contact with the liquid in the liquid container. On the other hand, when there is not enough liquid in the liquid container, the vibration region contacts the liquid remaining in the cavity in the liquid container, or does not contact the liquid but contacts the gas or the vacuum.

  The actuator 106 of the present invention is provided with a cavity 162, whereby the liquid in the liquid container can be designed to remain in the vibration region of the actuator 106. The reason is as follows.

  Depending on the mounting position and mounting angle of the actuator on the liquid container, the liquid may adhere to the vibration area of the actuator even though the liquid level of the liquid in the liquid container is below the mounting position of the actuator. is there. When the actuator detects the presence or absence of liquid only by the presence or absence of liquid in the vibration region, the liquid attached to the vibration region of the actuator hinders accurate detection of the presence or absence of liquid. For example, when the liquid level is below the mounting position of the actuator, if the liquid container is swung due to the reciprocating movement of the carriage, etc. An erroneous determination is made that there is sufficient liquid in the liquid container. Therefore, conversely, even when liquid remains there, by actively providing a cavity designed to accurately detect the presence or absence of liquid, the liquid container was swung and the liquid level was ruffled However, the malfunction of the actuator can be prevented. In this way, malfunctions can be prevented by using an actuator having a cavity.

  As shown in FIG. 2E, the case where there is no liquid in the liquid container and the liquid in the liquid container remains in the cavity 162 of the actuator 106 is set as the threshold value for the presence or absence of liquid. That is, if there is no liquid around the cavity 162 and there is less liquid in the cavity than this threshold, it is determined that there is no ink. If there is liquid around the cavity 162 and there is more liquid than this threshold, ink is present to decide. For example, when the actuator 106 is mounted on the side wall of the liquid container, it is determined that there is no ink when the liquid in the liquid container is below the mounting position of the actuator, and the liquid in the liquid container is above the mounting position of the actuator. In some cases, it is determined that ink is present. By setting the threshold value in this way, it is determined that there is no ink even when the ink in the cavity has dried and the ink has run out. Even if it adheres to the cavity, the threshold value is not exceeded, so it can be determined that there is no ink.

  Here, the operation and principle of detecting the state of the liquid in the liquid container from the resonance frequency of the medium and the vibrating portion of the actuator 106 by measuring the back electromotive force will be described with reference to FIGS. In the actuator 106, a voltage is applied to the upper electrode 164 and the lower electrode 166 via the upper electrode terminal 168 and the lower electrode terminal 170, respectively. An electric field is generated in a portion of the piezoelectric layer 160 sandwiched between the upper electrode 164 and the lower electrode 166. The piezoelectric layer 160 is deformed by the electric field. When the piezoelectric layer 160 is deformed, the vibration region of the vibration plate 176 is flexibly vibrated. For a while after the piezoelectric layer 160 is deformed, the flexural vibration remains in the vibration portion of the actuator 106.

  The residual vibration is free vibration between the vibration part of the actuator 106 and the medium. Therefore, by setting the voltage applied to the piezoelectric layer 160 to a pulse waveform or a rectangular wave, it is possible to easily obtain the resonance state between the vibrating portion and the medium after the voltage is applied. The residual vibration causes the vibration portion of the actuator 106 to vibrate, so that the piezoelectric layer 160 is also deformed. Accordingly, the piezoelectric layer 160 generates a counter electromotive force. The counter electromotive force is detected through the upper electrode 164, the lower electrode 166, the upper electrode terminal 168 and the lower electrode terminal 170. Since the resonance frequency can be specified by the detected back electromotive force, the state of the liquid in the liquid container can be detected.

In general, the resonant frequency fs is
fs = 1 / (2 * π * (M * Cact) ^1/2 ) (Formula 1)
It is represented by Here, M is the sum of the inertance Mact and the additional inertance M ′ of the vibration part. Cact is the compliance of the vibration part.

  FIG. 1C is a cross-sectional view of the actuator 106 when no ink remains in the cavity in this embodiment. FIGS. 2A and 2B are equivalent circuits of the vibrating portion of the actuator 106 and the cavity 162 when no ink remains in the cavity.

Mact is obtained by dividing the product of the thickness of the vibration part and the density of the vibration part by the area of the vibration part. In more detail, as shown in FIG.
Mact = Mpzt + Melectrode1 + Melectrode2 + Mvib (Formula 2)
It is expressed. Here, Mpzt is obtained by dividing the product of the thickness of the piezoelectric layer 160 and the density of the piezoelectric layer 160 in the vibrating portion by the area of the piezoelectric layer 160. Melectrode1 is obtained by dividing the product of the thickness of the upper electrode 164 and the density of the upper electrode 164 in the vibrating portion by the area of the upper electrode 164. Melectrode2 is obtained by dividing the product of the thickness of the lower electrode 166 and the density of the lower electrode 166 in the vibrating portion by the area of the lower electrode 166. Mvib is obtained by dividing the product of the thickness of the diaphragm 176 and the density of the diaphragm 176 in the vibration section by the area of the vibration region of the diaphragm 176. However, in this embodiment, Mact can be calculated from the thickness, density, and area of the entire vibration portion, and in this embodiment, each of the vibration regions of the piezoelectric layer 160, the upper electrode 164, the lower electrode 166, and the vibration plate 176 Although the areas have the above-described magnitude relationship, the difference between the areas is preferably small. In the present embodiment, in the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166, it is preferable that portions other than the circular portion, which is the main portion thereof, are so small as to be negligible with respect to the main portion. Accordingly, in the actuator 106, Mact is the sum of the inertances of the vibration regions of the upper electrode 164, the lower electrode 166, the piezoelectric layer 160 and the vibration plate 176. The compliance Cact is a compliance of a portion formed by the vibration region of the upper electrode 164, the lower electrode 166, the piezoelectric layer 160, and the vibration plate 176.

2A, FIG. 2B, FIG. 2D, and FIG. 2F show equivalent circuits of the vibrating portion of the actuator 106 and the cavity 162. In these equivalent circuits, Cact is The compliance of the vibration part of the actuator 106 is shown. Cpzt, Celectrode1, Celectrode2, and Cvib respectively indicate the compliance of the piezoelectric layer 160, the upper electrode 164, the lower electrode 166, and the diaphragm 176 in the vibration part. Cact is expressed by Equation 3 below.
1 / Cact = (1 / Cpzt) + (1 / Celectrode1) + (1 / Celectrode2) + (1 / Cvib) (Formula 3)
From Equation 2 and Equation 3, FIG. 2A can also be expressed as FIG.

  The compliance Cact represents a volume that can receive the medium by deformation when pressure is applied to the unit area of the vibration part. The compliance Cact may be said to represent the ease of deformation.

FIG. 2C is a cross-sectional view of the actuator 106 when the liquid is sufficiently contained in the liquid container and the medium is filled around the vibration region of the actuator 106. M′max in FIG. 2C represents the maximum value of additional inertance when the medium is sufficiently accommodated in the liquid container and the medium is filled around the vibration region of the actuator 106. M 'max is
M′max = (π * ρ / (2 * k ³ )) * (2 * (2 * k * a) ³ / (3 * π)) / (π * a ² ) ² (Formula 4)
(A is the radius of the vibration part, ρ is the density of the medium, and k is the wave number.)
It is represented by Equation 4 is established when the vibration region of the actuator 106 is a circle having a radius a. The additional inertance M ′ is an amount indicating that the mass of the vibration part is apparently increased by the action of the medium in the vicinity of the vibration part. As can be seen from Equation 4, M′max varies greatly depending on the radius a of the vibrating portion and the density ρ of the medium.

Wave number k is
k = 2 * π * fact / c (Formula 5)
(Fact is the resonance frequency of the vibrating part when the liquid is not touching. C is the speed of sound propagating through the medium.)
It is represented by

  2D shows an equivalent circuit of the vibration part of the actuator 106 and the cavity 162 in the case of FIG. 2C where the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. Indicates.

FIG. 2E is a cross-sectional view of the actuator 106 when the liquid in the liquid container is consumed and there is no liquid around the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. Show. Formula 4 is a formula representing the maximum inertance M′max determined from the density ρ of the ink, for example, when the liquid container is filled with liquid. On the other hand, when the liquid in the liquid container is consumed, and the liquid around the vibration region of the actuator 106 becomes gas or vacuum while the liquid remains in the cavity 162,
M ′ = ρ * t / S (Formula 6)
It can be expressed. t is the thickness of the medium involved in the vibration. S is the area of the vibration region of the actuator 106. When this vibration region is a circle having a radius a, S = π * a ² . Therefore, the additional inertance M ′ follows the equation 4 when the liquid is sufficiently contained in the liquid container and the liquid is filled around the vibration region of the actuator 106. On the other hand, when the liquid is consumed and the liquid around the vibration region of the actuator 106 becomes a gas or a vacuum while the liquid remains in the cavity 162, Equation 6 is satisfied.

  Here, as shown in FIG. 2E, the liquid in the liquid container is consumed and there is no liquid around the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. For the sake of convenience, the inertance M ′ is referred to as M′cav, and is distinguished from the additional inertance M′max in the case where liquid is filled around the vibration region of the actuator 106.

  FIG. 2F shows the case of FIG. 2E in which the liquid in the liquid container is consumed and there is no liquid around the vibration region of the actuator 106, but the liquid remains in the cavity 162 of the actuator 106. 3 shows an equivalent circuit of the vibrating portion of the actuator 106 and the cavity 162.

Here, the parameters related to the state of the medium are the density ρ of the medium and the thickness t of the medium in Equation 6. When the liquid is sufficiently stored in the liquid container, the liquid comes into contact with the vibrating portion of the actuator 106, and when the liquid is not sufficiently stored in the liquid container, the liquid remains in the cavity, Alternatively, gas or vacuum comes into contact with the vibrating portion of the actuator 106. When the liquid around the actuator 106 is consumed and the added inertance in the process of shifting from M′max in FIG. 2C to M′cav in FIG. 2E is M′var, the liquid is contained in the liquid container. Since the medium density ρ and the medium thickness t change depending on the state, the additional inertance M′var changes and the resonance frequency fs also changes. Therefore, the presence or absence of liquid in the liquid container can be detected by specifying the resonance frequency fs. When M′cav is expressed using Equation 6, the cavity depth d is substituted for t in Equation 6,
M′cav = ρ * d / S (Formula 7)
It becomes.

  Even if the mediums are different types of liquid, the density ρ varies depending on the composition, so that the additional inertance M ′ changes and the resonance frequency fs also changes. Therefore, the type of liquid can be detected by specifying the resonance frequency fs.

  If only one of ink or air is in contact with the vibrating portion of the actuator 106 and they are not mixed, the difference in M ′ can be detected even by calculation using Equation 4.

  FIG. 3A is a graph showing the relationship between the amount of ink in the ink tank and the resonance frequency fs of the ink and the vibration part. Here, ink will be described as an example of liquid. The vertical axis represents the resonance frequency fs, and the horizontal axis represents the ink amount. When the ink composition is constant, the resonance frequency fs increases as the remaining ink amount decreases.

  When ink is sufficiently stored in the ink container and the ink is filled around the vibration region of the actuator 106, the maximum added inertance M'max is a value expressed by the following equation (4). On the other hand, when the ink is consumed and the liquid remains in the cavity 162 and the ink is not filled around the vibration region of the actuator 106, the additional inertance M′var is expressed by the equation 6 based on the thickness t of the medium. Is calculated by Since t in Equation 6 is the thickness of the medium involved in vibration, the ink gradually increases by reducing d (see FIG. 1B) of the cavity 162 of the actuator 106, that is, by sufficiently thinning the substrate 178. It is also possible to detect the process of being consumed by the battery (see FIG. 2C). Here, tink is the thickness of ink involved in vibration, and tink-max is the tink at M'max. For example, the actuator 106 is disposed almost horizontally with respect to the ink level on the bottom surface of the ink cartridge. When the ink is consumed and the ink level reaches the height of t from the actuator 106, M'var gradually changes according to Equation 6, and the resonance frequency fs gradually changes according to Equation 1. Therefore, as long as the ink level is within the range t, the actuator 106 can gradually detect the ink consumption state.

  Further, by increasing or decreasing the vibration area of the actuator 106 and arranging it vertically, S in Equation 6 changes according to the position of the liquid level due to ink consumption. Therefore, the actuator 106 can also detect a process in which ink is gradually consumed. For example, the actuator 106 is disposed on the side wall of the ink cartridge substantially perpendicular to the ink level. When the ink is consumed and the ink level reaches the vibration region of the actuator 106, the additional inertance M 'decreases as the water level decreases, so that the resonance frequency fs gradually increases according to Equation 1. Therefore, as long as the ink level is within the range of the diameter 2a of the cavity 162 (see FIG. 2C), the actuator 106 can gradually detect the ink consumption state.

  A curve X in FIG. 3A shows the amount of ink stored in the ink tank and the ink and the ink when the cavity 162 of the actuator 106 is sufficiently shallow or the vibration region of the actuator 106 is sufficiently large or long. The relationship with the resonant frequency fs of a vibration part is represented. It can be understood that the amount of ink in the ink tank decreases and the resonance frequency fs of the ink and the vibration part gradually changes.

More specifically, the case where the process in which ink is gradually consumed can be detected means that both liquid and gas having different densities exist in the vicinity of the vibration region of the actuator 106 and are involved in vibration. Is the case. As the ink is gradually consumed, the medium involved in the vibration around the vibration region of the actuator 106 increases the gas while decreasing the liquid. For example, when the actuator 106 is disposed horizontally with respect to the ink level and when tink is smaller than tink-max, the medium involved in the vibration of the actuator 106 includes both ink and gas. Therefore, when the area S of the vibration region of the actuator 106 is expressed as a state where M′max or less in Expression 4 is expressed by the additional mass of ink and gas,
M ′ = M′air + M′ink = ρair * tair / S + ρink * tink / S (Formula 8)
It becomes. Here, M′air is an inertance of air, and M′ink is an inertance of ink. ρair is the density of air, and ρink is the density of ink. tair is the thickness of air involved in vibration, and tink is the thickness of ink involved in vibration. Among the media involved in vibration around the vibration region of the actuator 106, as the liquid decreases and the gas increases, the tair increases when the actuator 106 is arranged substantially horizontally with respect to the ink surface. Tink decreases. Thereby, M′var gradually decreases and the resonance frequency gradually increases. Therefore, it is possible to detect the amount of ink remaining in the ink tank or the amount of ink consumed. The reason why only the liquid density is calculated in Expression 7 is that it is assumed that the air density is negligibly small relative to the liquid density.

In the case where the actuator 106 is disposed substantially perpendicular to the ink liquid level, the medium that is involved in the vibration of the actuator 106 is the ink only area and the medium that is involved in the vibration of the actuator 106 among the vibration areas of the actuator 106. It is considered as an equivalent circuit (not shown) in parallel with the gas region. If the medium related to the vibration of the actuator 106 is Sink and the area of the medium only related to the vibration of the actuator 106 is Sair, then Sair.
1 / M ′ = 1 / M′air + 1 / M′ink = Sair / (ρair * tair) + Sink / (ρink * tink) (Equation 9)
It becomes.

  Equation 9 is applied when ink is not held in the cavity of the actuator 106. The case where ink is held in the cavity of the actuator 106 can be calculated by Equation 7, Equation 8, and Equation 9.

  On the other hand, when the substrate 178 is thick, that is, when the depth d of the cavity 162 is deep and d is relatively close to the medium thickness tink-max, or when the vibration region is very small compared to the height of the liquid container In practice, rather than detecting a process in which the ink gradually decreases, it is detected that the ink level is higher than the actuator mounting position. In other words, the presence or absence of ink in the vibration region of the actuator is detected. For example, the curve Y in FIG. 3A shows the relationship between the amount of ink in the ink tank and the resonance frequency fs of the ink and the vibration part in the case of a small circular vibration region. A state is shown in which the ink and the resonance frequency fs of the vibrating part change drastically between the ink amount Q before and after the ink level in the ink tank passes through the mounting position of the actuator. From this, it is possible to detect whether or not a predetermined amount of ink remains in the ink tank.

  The method of detecting the presence / absence of liquid using the actuator 106 detects the presence / absence of ink by the diaphragm 176 coming into direct contact with the liquid. Is expensive. Further, the method of detecting the presence or absence of ink by conductivity using an electrode is affected by the attachment position to the liquid container and the type of ink, but the method of detecting the presence or absence of liquid using the actuator 106 It is not affected by the mounting position on the container and the type of ink. Furthermore, since both oscillation and detection of the presence / absence of liquid can be performed using a single actuator 106, the liquid can be compared with a method in which oscillation and detection of the presence / absence of liquid are performed using different sensors. The number of sensors attached to the container can be reduced. Therefore, the liquid container can be manufactured at a low cost. Furthermore, by setting the vibration frequency of the piezoelectric layer 160 in the non-audible region, it is possible to quiet the sound generated during the operation of the actuator 106.

  FIG. 3B shows the relationship between the ink density and the resonance frequency fs of the ink and the vibration part on the curve Y in FIG. Ink is used as an example of the liquid. As shown in FIG. 3B, when the ink density is increased, the additional inertance is increased, so that the resonance frequency fs is decreased. That is, the resonance frequency fs varies depending on the type of ink. Therefore, by measuring the resonance frequency fs, it is possible to confirm whether or not inks having different densities are mixed when refilling the ink.

  That is, it is possible to identify ink tanks containing different types of ink.

  Subsequently, the conditions under which the liquid state can be accurately detected when the size and shape of the cavity are set so that the liquid remains in the cavity 162 of the actuator 106 even when the liquid in the liquid container is empty. Detailed description. If the actuator 106 can detect the liquid state when the cavity 162 is filled with the liquid, the actuator 106 can detect the liquid state even when the cavity 162 is not filled with the liquid.

  The resonance frequency fs is a function of the inertance M. The inertance M is the sum of the inertance Mact and the additional inertance M ′ of the vibration part. Here, the additional inertance M ′ is related to the liquid state. The additional inertance M ′ is an amount indicating that the mass of the vibration part is apparently increased by the action of the medium in the vicinity of the vibration part. That is, it means an increase in mass of the vibration part due to apparent absorption of the medium by vibration of the vibration part.

  Therefore, when M ′ cav is larger than M ′ max in Equation 4, all of the apparently absorbing medium is the liquid remaining in the cavity 162. Therefore, it is the same as the state where the liquid container is filled with the liquid. In this case, since M 'does not change, the resonance frequency fs also does not change. Therefore, the actuator 106 cannot detect the state of the liquid in the liquid container.

  On the other hand, when M ′ cav is smaller than M ′ max in Equation 4, the apparently absorbing medium is the liquid remaining in the cavity 162 and the gas or vacuum in the liquid container. At this time, unlike the state where the liquid container is filled with the liquid, M ′ changes, so the resonance frequency fs changes. Therefore, the actuator 106 can detect the state of the liquid in the liquid container.

  That is, when the liquid in the liquid container is empty and the liquid remains in the cavity 162 of the actuator 106, the condition under which the actuator 106 can accurately detect the liquid state is that M′cav is higher than M′max. It is small. The condition M′max> M′cav that allows the actuator 106 to accurately detect the liquid state is not related to the shape of the cavity 162.

Here, M′cav is the mass of the liquid having a volume approximately equal to the volume of the cavity 162. Therefore, from the inequality M′max> M′cav, the condition under which the actuator 106 can accurately detect the liquid state can be expressed as the condition of the capacity of the cavity 162. For example, when the radius of the opening 161 of the circular cavity 162 is a and the depth of the cavity 162 is d,
M′max> ρ * d / πa ² (Formula 10)
It is. When formula 10 is expanded, a / d> 3 * π / 8 (formula 11)
This condition is required. Expressions 10 and 11 are valid only when the shape of the cavity 162 is circular. Using the formula of M′max in the case of non-circularity and calculating by replacing πa ^{2 in} formula 10 with its area, the relationship between the dimensions such as the width and length of the cavity and the depth can be derived.

  Therefore, if the actuator 106 has the cavity 162 having the radius a of the opening 161 and the depth d of the cavity 162 satisfying Expression 11, the liquid in the liquid container is empty and the liquid is contained in the cavity 162. Even if it remains, the liquid state can be detected without malfunction.

  Since the additional inertance M 'also affects the acoustic impedance characteristics, it can be said that the method of measuring the counter electromotive force generated in the actuator 106 due to residual vibration detects at least a change in acoustic impedance.

  Further, according to this embodiment, the back electromotive force generated in the actuator 106 due to the subsequent residual vibration after the actuator 106 generates vibration is measured. However, it is not always necessary for the vibrating portion of the actuator 106 to vibrate the liquid by its own vibration caused by the drive voltage. That is, even if the vibration part does not oscillate by itself, it vibrates with a certain range of liquid in contact therewith, so that the piezoelectric layer 160 bends and deforms. This residual vibration generates a counter electromotive force voltage in the piezoelectric layer 160 and transmits the counter electromotive force voltage to the upper electrode 164 and the lower electrode 166. The state of the medium may be detected by using this phenomenon. For example, in an ink jet recording apparatus, even if the state of the ink tank or the ink in the ink tank is detected by using the vibration around the vibration part of the actuator generated by the vibration caused by the reciprocating movement of the carriage by the scanning of the print head during printing Good.

  The frequency at which the actuator 106 oscillates is preferably a frequency in the non-audible region. For example, the frequency is preferably between 100 kHz and 500 kHz. In recent years, sound generated during operation of an ink jet recording apparatus has become extremely small, and if the frequency generated when the actuator 106 is driven is in an audible range, the sound generated by the actuator 106 becomes relatively conspicuous. The recording device user may feel uncomfortable. Therefore, it is desirable to set the frequency at which the actuator 106 oscillates to a frequency in the non-audible region so that the user of the recording apparatus does not feel the vibration generated by the actuator 106 uncomfortable.

  On the other hand, even if the same type of ink cartridge contains the same amount of ink of the same type, for example, the same color, the value of the generated resonance frequency differs slightly depending on the individual difference of each actuator. Therefore, when each ink cartridge is in an ink full state, the resonance frequency is measured and stored in advance in the semiconductor memory 7 or the memory in the recording apparatus. Then, the ink consumption state of each ink cartridge can be detected by comparing the stored resonance frequency with the frequency measured when the ink cartridge is consumed. For example, when a new ink cartridge is installed in the recording apparatus, the frequency at the time of ink full is measured and stored in the memory, and the frequency measured when the ink is consumed is compared with the frequency at the time of ink full. The consumption state of ink may be detected by comparing the frequency. In addition, when the ink cartridge is manufactured, the frequency when the ink is full is measured in advance, and the measurement result is stored in the semiconductor storage means 7, and the frequency measured when the ink is consumed is compared with the frequency when the ink is full. Thus, the ink consumption state may be detected.

  FIG. 4 shows the relationship between the remaining amount of ink in the ink cartridge and the combination pattern of the resonance frequency in the primary mode and the secondary mode. For each of the ink cartridges A, B, and C having different ink remaining amounts, the resonance frequency of the primary mode, the resonance frequency of the secondary mode, and the resonance frequency of the primary mode and the resonance frequency of the secondary mode The numerical value of the combination pattern is shown.

  The primary mode is the primary frequency of the counter electromotive force waveform due to the residual vibration of the actuator (elastic wave generating means) 106, and the secondary mode is the secondary frequency of the counter electromotive force waveform due to the residual vibration of the actuator 106. To express. Since the frequency detected from the back electromotive force waveform due to the residual vibration of the actuator 106 substantially matches the maximum value of the admittance characteristic measured by the impedance analyzer, measuring the frequency of the back electromotive force waveform is an acoustic impedance. Equivalent to finding the singularity of.

  Since the remaining amounts of ink in the ink cartridges A, B, and C are different, the numerical patterns resulting from the combination of the resonance frequency of the primary mode and the resonance frequency of the secondary mode are different. By measuring both the resonance frequency and the secondary mode resonance frequency, it is possible to determine the remaining amount of ink stored in the ink cartridge mounted on the recording apparatus.

  For example, as shown in FIG. 4, the ink cartridge A, the ink cartridge B, and the ink cartridge C having different ink remaining amounts are numerical patterns of combinations of the resonance frequency of the primary mode and the resonance frequency of the secondary mode. Are different. Therefore, a numerical pattern of a combination of the resonance frequencies of the primary mode and the secondary mode can be used as a pattern indicating the remaining ink amount of each ink cartridge.

  The ink cartridge B has a resonance frequency pattern in which the peak pattern of the primary mode and the secondary mode is shifted 100 kHz lower than that of the ink cartridge A. The ink cartridge C has a resonance frequency pattern in which the resonance frequency pattern of the primary mode and the secondary mode is shifted 100 kHz higher than that of the ink cartridge A. Thus, the resonance frequency patterns of the primary mode and the secondary mode differ depending on the remaining amount of ink stored in the ink cartridge. Therefore, by detecting the resonance frequencies of both the primary mode and the secondary mode, and recognizing the numerical pattern of the combination of the resonance frequencies as a unique pattern of the remaining ink amount of the measured ink cartridge, The remaining amount of ink stored in the cartridge can be determined.

  Here, the resonance frequencies of the two modes of the primary mode and the secondary mode are detected, but the remaining amount of ink may be determined by detecting the resonance frequencies of a plurality of modes. For example, the remaining amount of ink may be determined by detecting the resonance frequency of two modes of the primary mode and the tertiary mode, and the resonance frequency of the two modes of the secondary mode and the tertiary mode is detected. By doing so, the remaining amount of ink may be determined.

  5A and 5B show a residual vibration waveform of the actuator 106 and a method for measuring the residual vibration after the actuator 106 is vibrated. The upper and lower levels of the ink level at the mounting position level of the actuator 106 in the ink cartridge can be detected by a change in the frequency or amplitude of the residual vibration after the actuator 106 oscillates. 5A and 5B, the vertical axis indicates the voltage of the counter electromotive force generated by the residual vibration of the actuator 106, and the horizontal axis indicates time. The residual vibration of the actuator 106 generates a voltage analog signal waveform as shown in FIGS. 5 (A) and 5 (B). Next, the analog signal is converted into a digital numerical value corresponding to the frequency of the signal.

  In the example shown in FIGS. 5A and 5B, the presence or absence of ink is detected by measuring the time during which four pulses from the fourth pulse to the eighth pulse of the analog signal occur.

  More specifically, after the actuator 106 oscillates, the number of times that a predetermined reference voltage set in advance is crossed from the low voltage side to the high voltage side is counted. The digital signal is set to High between 4 counts and 8 counts, and the time from 4 counts to 8 counts is measured by a predetermined clock pulse.

  FIG. 5A shows a waveform when the ink liquid level is higher than the mounting position level of the actuator 106. On the other hand, FIG. 5B shows a waveform when there is no ink at the mounting position level of the actuator 106. Comparing FIG. 5A and FIG. 5B, it can be seen that FIG. 5A has a longer time from 4 to 8 counts than FIG. 5B. In other words, the time from 4 counts to 8 counts varies depending on the presence or absence of ink. By using this time difference, it is possible to detect the ink consumption state. The reason for counting from the fourth count of the analog waveform is to start measurement after the vibration of the actuator 106 is stabilized. The count from the fourth count is merely an example, and the count may be counted from an arbitrary count. Here, signals from the 4th count to the 8th count are detected, and a time from the 4th count to the 8th count is measured by a predetermined clock pulse. Thereby, the resonance frequency is obtained. The clock pulse is preferably a clock pulse equal to a clock for controlling a semiconductor memory device or the like attached to the ink cartridge. It is not necessary to measure the time up to the 8th count, and it may be counted up to an arbitrary count. In FIG. 5, the time from the 4th count to the 8th count is measured, but the times within different count intervals may be detected according to the circuit configuration for detecting the frequency.

  For example, when the ink quality is stable and the fluctuation of the peak amplitude is small, the resonance frequency may be obtained by detecting the time from the 4th count to the 6th count in order to increase the detection speed. . When the ink quality is unstable and the fluctuation of the pulse amplitude is large, the time from the 4th count to the 12th count may be detected in order to accurately detect the residual vibration.

  As another example, the wave number of the voltage waveform of the back electromotive force within a predetermined period may be counted (not shown). The resonance frequency can also be obtained by this method. More specifically, after the actuator 106 oscillates, the digital signal is set to High for a predetermined period, and the number of times the predetermined reference voltage is crossed from the low voltage side to the high voltage side is counted. The presence or absence of ink can be detected by measuring the count number.

  Further, as can be seen by comparing FIG. 5A and FIG. 5B, the amplitude of the back electromotive force waveform between when the ink is filled in the ink cartridge and when the ink is not inside the ink cartridge. Is different. Therefore, the ink consumption state in the ink cartridge may be detected by measuring the amplitude of the counter electromotive force waveform without obtaining the resonance frequency. More specifically, for example, a reference voltage is set between the peak of the counter electromotive force waveform in FIG. 5A and the peak of the counter electromotive force waveform in FIG. When the digital signal is High at a predetermined time after the actuator oscillates and the back electromotive force waveform crosses the reference voltage, it is determined that there is no ink. If the back electromotive force waveform does not cross the reference voltage, it is determined that ink is present.

  The residual vibration of the actuator 106 is preferably measured when the carriage is not moving or when the recording head is not printing. When residual vibration is measured during printing of the recording head, the central processing unit (CPU) of the ink cartridge recording device is used for measurement of residual vibration, so the time that the CPU can use for printing is reduced and the printing speed is reduced. descend. Therefore, the residual vibration is measured when the recording head not using the CPU is not printing, thereby preventing the printing speed from being lowered. Further, in the case of an ink container that is mounted on a carriage and moves with the carriage, if residual vibration is measured during printing of the recording head, the ink container moves and the ink in the ink container is shaken, so that the residual vibration is accurately detected. Cannot be measured. Therefore, it is preferable to measure residual vibration during non-printing. In addition, during non-printing, the motor for driving the carriage is stopped, and measurement can be performed while avoiding noise when the recording head and carriage motor are driven. Therefore, the residual vibration can be measured more accurately. The time when the recording head is not printed includes time such as page break, cleaning, power-on, immediately before power-off, that is, time until the recording apparatus actually stops after power-off.

  FIG. 6 shows a method for manufacturing the actuator 106. A plurality of actuators 106 (four in the example of FIG. 6) are integrally formed. The actuator 106 shown in FIG. 7 is manufactured by cutting the integrally molded product of the plurality of actuators shown in FIG. 6 at each actuator 106. When the piezoelectric elements of the plurality of integrally formed actuators 106 shown in FIG. 6 are circular, the actuator 106 shown in FIG. 1 can be manufactured by cutting the integrally formed product at each actuator 106. By integrally forming the plurality of actuators 106, the plurality of actuators 106 can be efficiently manufactured at the same time, and handling during transportation becomes easy.

  The actuator 106 includes a thin plate or vibration plate 176, a substrate 178, an elastic wave generating means or piezoelectric element 174, a terminal forming member or upper electrode terminal 168, and a terminal forming member or lower electrode terminal 170. The piezoelectric element 174 includes a piezoelectric diaphragm or piezoelectric layer 160, an upper electrode or upper electrode 164, and a lower electrode or lower electrode 166. A vibration plate 176 is formed on the upper surface of the substrate 178, and a lower electrode 166 is formed on the upper surface of the vibration plate 176. A piezoelectric layer 160 is formed on the upper surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Therefore, the main part of the piezoelectric layer 160 is formed so as to be sandwiched from above and below by the main part of the upper electrode 164 and the main part of the lower electrode 166.

  A plurality of (four in the example of FIG. 6) piezoelectric elements 174 are formed on the diaphragm 176. A lower electrode 166 is formed on the surface of the diaphragm 176, a piezoelectric layer 160 is formed on the surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Upper electrode terminals 168 and lower electrode terminals 170 are formed at the ends of the upper electrode 164 and the lower electrode 166. The four actuators 106 are cut separately and used individually.

  FIG. 7 shows a cross section of a part of the actuator 106 having a rectangular piezoelectric element.

  FIG. 8 shows an entire cross section of the actuator 106 shown in FIG. A through hole 178 a is formed on the surface of the substrate 178 facing the piezoelectric element 174. The through hole 178a is sealed by the vibration plate 176. The diaphragm 176 is made of an elastically deformable material such as alumina or zirconia oxide. A piezoelectric element 174 is formed on the vibration plate 176 so as to face the through hole 178a. The lower electrode 166 is formed on the surface of the diaphragm 176 so as to extend in one direction from the region of the through hole 178a, to the left in FIG. The upper electrode 164 is formed on the surface of the piezoelectric layer 160 so as to extend from the region of the through hole 178a in the opposite direction to the lower electrode, and to the right in FIG. The upper electrode terminal 168 and the lower electrode terminal 170 are formed on the upper surfaces of the auxiliary electrode 172 and the lower electrode 166, respectively. The lower electrode terminal 170 is in electrical contact with the lower electrode 166, and the upper electrode terminal 168 is in electrical contact with the upper electrode 164 via the auxiliary electrode 172, so that a signal between the piezoelectric element and the outside of the actuator 106 can be transmitted. Deliver it. The upper electrode terminal 168 and the lower electrode terminal 170 have a height equal to or higher than the height of the piezoelectric element in which the electrode and the piezoelectric layer are combined.

  FIG. 9 shows a manufacturing method of the actuator 106 shown in FIG. First, a through hole 940a is drilled in the green sheet 940 using a press or laser processing. The green sheet 940 becomes the substrate 178 after firing. The green sheet 940 is formed of a material such as ceramic. Next, the green sheet 941 is laminated on the surface of the green sheet 940. The green sheet 941 becomes the diaphragm 176 after firing. The green sheet 941 is formed of a material such as zirconia oxide. Next, a conductive layer 942, a piezoelectric layer 160, and a conductive layer 944 are sequentially formed on the surface of the green sheet 941 by a method such as pressure film printing. The conductive layer 942 later becomes the lower electrode 166, and the conductive layer 944 later becomes the upper electrode 164. Next, the formed green sheet 940, green sheet 941, conductive layer 942, piezoelectric layer 160, and conductive layer 944 are dried and fired. The spacer members 947 and 948 raise the height of the upper electrode terminal 168 and the lower electrode terminal 170 to make them higher than the piezoelectric element. The spacer members 947 and 948 are formed by printing the same material as the green sheets 940 and 941 or by laminating green sheets. The spacer members 947 and 948 can reduce the material of the upper electrode terminal 168 and the lower electrode terminal 170, which are noble metals, and can reduce the thickness of the upper electrode terminal 168 and the lower electrode terminal 170. The electrode terminal 170 can be printed with high accuracy, and the height can be further stabilized.

  If the connection portion 944 ′ and the spacer members 947 and 948 with the conductive layer 944 are formed at the same time as the formation of the conductive layer 942, the upper electrode terminal 168 and the lower electrode terminal 170 can be easily formed or firmly fixed. Finally, an upper electrode terminal 168 and a lower electrode terminal 170 are formed in end regions of the conductive layer 942 and the conductive layer 944. When the upper electrode terminal 168 and the lower electrode terminal 170 are formed, the upper electrode terminal 168 and the lower electrode terminal 170 are formed so as to be electrically connected to the piezoelectric layer 160.

  FIG. 10 shows still another embodiment of an ink cartridge to which the present invention is applied. FIG. 10A is a cross-sectional view of the bottom of the ink cartridge according to the present embodiment. The ink cartridge of the present embodiment has a through hole 1c on the bottom surface 1a of the container 1 that stores ink. The bottom of the through-hole 1c is closed by the actuator 650 to form an ink reservoir.

  FIG. 10B shows a detailed cross section of the actuator 650 and the through hole 1c shown in FIG. FIG. 10C shows a plane of the actuator 650 and the through hole 1c shown in FIG. The actuator 650 has a diaphragm 72 and a piezoelectric element 73 fixed to the diaphragm 72. The actuator 650 is fixed to the bottom surface of the container 1 so that the piezoelectric element 73 faces the through hole 1c through the vibration plate 72 and the substrate 71. The diaphragm 72 is elastically deformable and has ink resistance.

  Depending on the amount of ink in the container 1, the amplitude and frequency of the counter electromotive force generated by the residual vibration of the piezoelectric element 73 and the diaphragm 72 change. A through hole 1c is formed at a position facing the actuator 650, and a minimum amount of ink is secured in the through hole 1c. Therefore, the ink end of the container 1 can be reliably detected by measuring in advance the vibration characteristics of the actuator 650 determined by the amount of ink secured in the through hole 1c.

  FIG. 11 shows another embodiment of the through hole 1c. In each of FIGS. 11A, 11B, and 11C, the left figure shows a state where no ink K is present in the through hole 1c, and the right figure shows a state where the ink K remains in the through hole 1c. Indicates. In the embodiment of FIG. 10, the side surface of the through hole 1c is formed as a vertical wall. In FIG. 11A, the through-hole 1c has a side surface 1d that is slanted in the vertical direction and is open to the outside. In FIG. 11B, step portions 1e and 1f are formed on the side surface of the through hole 1c. The upper step portion 1f is wider than the lower step portion 1e. In FIG. 11C, the through hole 1c has a groove 1g extending in the direction in which the ink K is easily discharged, that is, in the direction of the ink supply port 2.

  According to the shape of the through hole 1c shown in FIGS. 11A to 11C, the amount of ink K in the ink reservoir can be reduced. Therefore, since M′cav described in FIGS. 1 and 2 can be made smaller than M′max, the vibration characteristic of the actuator 650 at the time of ink end is determined by the amount of ink K that can be printed on the container 1. Since it can be greatly different from the remaining case, the ink end can be detected more reliably.

  FIG. 12 is a perspective view showing another embodiment of the actuator. The actuator 660 has a packing 76 outside the through hole 1c of the substrate or the mounting plate 72 constituting the actuator 660. A caulking hole 77 is formed on the outer periphery of the actuator 660. The actuator 660 is fixed to the container 1 by caulking through the caulking hole 77.

  FIGS. 13A and 13B are perspective views showing still another embodiment of the actuator. In the present embodiment, the actuator 670 includes a recess forming substrate 80 and a piezoelectric element 82. A recess 81 is formed on one surface of the recess forming substrate 80 by a technique such as etching, and a piezoelectric element 82 is attached to the other surface. Of the recess forming substrate 80, the bottom of the recess 81 acts as a vibration region. Therefore, the vibration region of the actuator 670 is defined by the peripheral edge of the recess 81. The actuator 670 is similar to the structure of the actuator 106 according to the embodiment of FIG. 1 in which the substrate 178 and the diaphragm 176 are integrally formed. Accordingly, the manufacturing process can be shortened when manufacturing the ink cartridge, and the cost is reduced. The actuator 670 has a size that can be embedded in the through hole 1 c provided in the container 1. Thereby, the recess 81 can also act as a cavity. The actuator 106 according to the embodiment shown in FIG. 1 may be formed so as to be embedded in the through hole 1c in the same manner as the actuator 670 according to the embodiment shown in FIG.

  FIG. 14 is a perspective view showing a configuration in which the actuator 106 is integrally formed as the mounting module body 100. The module body 100 is attached to a predetermined portion of the container 1 of the ink cartridge. The module body 100 is configured to detect the consumption state of the liquid in the container 1 by detecting a change in at least the acoustic impedance in the ink liquid. The module body 100 of the present embodiment includes a liquid container mounting portion 101 for mounting the actuator 106 to the container 1. The liquid container mounting portion 101 has a structure in which a cylindrical portion 116 that houses an actuator 106 that oscillates in response to a drive signal is placed on a base 102 having a substantially rectangular plane. When the module body 100 is mounted on the ink cartridge, the actuator 106 of the module body 100 is configured so as not to contact from the outside, so that the actuator 106 can be protected from external contact. The leading edge of the cylindrical portion 116 is rounded so that it can be easily fitted into a hole formed in the ink cartridge.

  FIG. 15 is an exploded view showing the configuration of the module body 100 shown in FIG. The module body 100 includes a liquid container mounting portion 101 made of resin, and a piezoelectric device mounting portion 105 having a plate 110 and a recess 113. Further, the module body 100 includes lead wires 104a and 104b, an actuator 106, and a film 108. Preferably, the plate 110 is made of a material that hardly rusts, such as stainless steel or a stainless alloy. The cylindrical portion 116 and the base 102 included in the liquid container mounting portion 101 have an opening 114 at the center so that the lead wires 104a and 104b can be accommodated, and can accommodate the actuator 106, the film 108, and the plate 110. A recess 113 is formed. The actuator 106 is joined to the plate 110 via the film 108, and the plate 110 and the actuator 106 are fixed to the liquid container mounting portion 101. Accordingly, the lead wires 104 a and 104 b, the actuator 106, the film 108, and the plate 110 are integrally attached to the liquid container attachment portion 101. The lead wires 104a and 104b are coupled to the upper electrode and the lower electrode of the actuator 106, respectively, and transmit a drive signal to the piezoelectric layer, while transmitting a resonance frequency signal detected by the actuator 106 to a recording device or the like. The actuator 106 oscillates temporarily based on the drive signal transmitted from the lead wires 104a and 104b. The actuator 106 vibrates residually after oscillation, and generates back electromotive force by the vibration. At this time, the resonance frequency corresponding to the liquid consumption state in the liquid container can be detected by detecting the vibration period of the counter electromotive force waveform. The film 108 adheres the actuator 106 and the plate 110 to make the actuator liquid-tight. The film 108 is preferably formed of polyolefin or the like and bonded by heat fusion. The film 108 adheres the actuator 106 and the plate 110 to make the actuator liquid-tight. When the actuator 106 and the plate 110 are bonded and fixed in a planar shape with the film 108, there is no variation depending on the bonding location, and portions other than the vibrating portion do not vibrate. Therefore, the change in the resonance frequency before and after the actuator 106 is bonded to the plate 110 is small.

  The plate 110 is circular, and the opening 114 of the base 102 is formed in a cylindrical shape. The actuator 106 and the film 108 are formed in a rectangular shape. The lead wire 104, the actuator 106, the film 108, and the plate 110 may be detachable from the base 102. The base 102, the lead wire 104, the actuator 106, the film 108, and the plate 110 are arranged symmetrically with respect to the central axis of the module body 100. Furthermore, the centers of the base 102, the actuator 106, the film 108, and the plate 110 are disposed on the substantially central axis of the module body 100.

  The area of the opening 114 of the base 102 is formed larger than the area of the vibration region of the actuator 106. A through hole 112 is formed at a position facing the vibration portion of the actuator 106 at the center of the plate 110. As shown in FIGS. 1 and 2, the actuator 106 is formed with a cavity 162, and the through hole 112 and the cavity 162 together form an ink reservoir. The thickness of the plate 110 is preferably smaller than the diameter of the through hole 112 in order to reduce the influence of residual ink. For example, it is preferable that the depth of the through hole 112 is not more than one third of the diameter. The through-hole 112 has a substantially perfect circular shape that is symmetric with respect to the central axis of the module body 100. The area of the through hole 112 is larger than the opening area of the cavity 162 of the actuator 106. The peripheral edge of the cross section of the through hole 112 may be a taper shape or a step shape. The module body 100 is mounted on the side, top, or bottom of the container 1 so that the through hole 112 faces the inside of the container 1. When the ink is consumed and the ink around the actuator 106 runs out, the resonance frequency of the actuator 106 changes greatly, so that a change in the ink level can be detected.

  FIG. 16 is a perspective view showing another embodiment of the module body. In the module body 400 of this embodiment, a piezoelectric device mounting portion 405 is formed in the liquid container mounting portion 401. In the liquid container mounting portion 401, a cylindrical column portion 403 is formed on a base 402 on a square whose plane is substantially rounded. Furthermore, the piezoelectric device mounting portion 405 includes a plate-like element 406 and a concave portion 413 that are erected on the cylindrical portion 403. The actuator 106 is disposed in the recess 413 provided on the side surface of the plate-like element 406. Note that the tip of the plate-like element 406 is chamfered at a predetermined angle so that it can be easily fitted into a hole formed in the ink cartridge.

  17 is an exploded perspective view showing the configuration of the module body 400 shown in FIG. Similar to the module body 100 shown in FIG. 14, the module body 400 includes a liquid container mounting portion 401 and a piezoelectric device mounting portion 405. The liquid container mounting portion 401 has a base 402 and a cylindrical portion 403, and the piezoelectric device mounting portion 405 has a plate-like element 406 and a recess 413. The actuator 106 is joined to the plate 410 and fixed to the recess 413. The module body 400 further includes lead wires 404a and 404b, an actuator 106, and a film 408.

  According to the present embodiment, the plate 410 has a rectangular shape, and the opening 414 provided in the plate-like element 406 is formed in a rectangular shape. The lead wires 404 a and 404 b, the actuator 106, the film 408, and the plate 410 may be configured to be detachable from the base 402. The actuator 106, the film 408, and the plate 410 are disposed symmetrically with respect to a central axis that passes through the center of the opening 414 and extends in the vertical direction with respect to the plane of the opening 414. Further, the centers of the actuator 406, the film 408, and the plate 410 are disposed on the substantially central axis of the opening 414.

  The area of the through hole 412 provided at the center of the plate 410 is formed larger than the area of the opening of the cavity 162 of the actuator 106. The cavity 162 and the through hole 412 of the actuator 106 together form an ink reservoir. The thickness of the plate 410 is smaller than the diameter of the through hole 412, and is preferably set to a size equal to or less than one third of the diameter of the through hole 412, for example. The through hole 412 has a substantially perfect circular shape that is symmetric with respect to the central axis of the module body 400. The peripheral edge of the cross section of the through hole 412 may be a taper shape or a step shape. The module body 400 can be attached to the bottom of the container 1 such that the through hole 412 is disposed inside the container 1. Since the actuator 106 is arranged in the container 1 so as to extend in the vertical direction, the ink end point is set by changing the height of the base 402 and changing the height at which the actuator 106 is arranged in the container 1. Can be easily changed.

  FIG. 18 shows still another embodiment of the module body. Similar to the module body 100 shown in FIG. 14, the module body 500 of FIG. 18 includes a liquid container mounting portion 501 having a base 502 and a cylindrical portion 503. The module body 500 further includes lead wires 504a and 504b, an actuator 106, a film 508, and a plate 510. The base 502 included in the liquid container mounting portion 501 has an opening 514 at the center so as to accommodate the lead wires 504a and 504b, and a recess 513 so as to accommodate the actuator 106, the film 508, and the plate 510. Is done. The actuator 106 is fixed to the piezoelectric device mounting portion 505 via the plate 510. Accordingly, the lead wires 504a and 504b, the actuator 106, the film 508, and the plate 510 are integrally attached to the liquid container attachment portion 501. In the module body 500 of the present embodiment, a cylindrical portion 503 whose upper surface is slanted in the vertical direction is formed on a base on a square whose plane is substantially rounded. The actuator 106 is disposed on a concave portion 513 provided obliquely in the vertical direction on the upper surface of the cylindrical portion 503.

  The tip of the module body 500 is inclined, and the actuator 106 is mounted on the inclined surface. Therefore, when the module body 500 is mounted on the bottom or side of the container 1, the actuator 106 is inclined with respect to the vertical direction of the container 1. The inclination angle of the tip of the module body 500 is preferably between approximately 30 ° and 60 ° in view of detection performance.

  The module body 500 is mounted on the bottom or side of the container 1 so that the actuator 106 is disposed in the container 1. When the module body 500 is attached to the side portion of the container 1, the actuator 106 is attached to the container 1 so as to face the upper side, the lower side, or the lateral side of the container 1 while being inclined. On the other hand, when the module body 500 is mounted on the bottom of the container 1, it is preferable that the actuator 106 is attached to the container 1 so as to face the ink supply port side of the container 1 while being inclined.

  FIG. 19 is a cross-sectional view of the vicinity of the bottom of the ink container when the module body 100 shown in FIG. The module body 100 is mounted so as to penetrate the side wall of the container 1. An O-ring 365 is provided on the joint surface between the side wall of the container 1 and the module body 100 to keep the module body 100 and the container 1 liquid-tight. The module body 100 preferably includes a cylindrical portion as described in FIG. 13 so that the O-ring can be sealed. By inserting the tip of the module body 100 into the container 1, the ink in the container 1 comes into contact with the actuator 106 through the through hole 112 of the plate 110. Since the resonance frequency of the residual vibration of the actuator 106 differs depending on whether the surrounding of the vibration part of the actuator 106 is liquid or gas, the ink consumption state can be detected using the module body 100. In addition to the module body 100, the module body 400 shown in FIG. 16, the module body 500 shown in FIG. 18, or the module bodies 700A and 700B and the mold structure 600 shown in FIG. The presence or absence of ink may be detected.

  20A shows a cross-sectional view of the ink container when the module body 700B is mounted on the container 1. FIG. In this embodiment, the module body 700B is used as one of the mounting structures. The module 700B is mounted on the container 1 such that the liquid container mounting portion 360 protrudes into the container 1. A through hole 370 is formed in the mounting plate 350, and the through hole 370 faces the vibration portion of the actuator 106. Further, a hole 382 is formed in the bottom wall of the module body 700B, and a piezoelectric device mounting portion 363 is formed. Actuator 106 is deployed to block one of the holes 382. Therefore, the ink comes into contact with the vibration plate 176 through the hole 382 of the piezoelectric device mounting portion 363 and the through hole 370 of the mounting plate 350. The hole 382 of the piezoelectric device mounting portion 363 and the through hole 370 of the mounting plate 350 together form an ink reservoir. The piezoelectric device mounting portion 363 and the actuator 106 are fixed by a mounting plate 350 and a film member. A sealing structure 372 is provided at a connection portion between the liquid container mounting portion 360 and the container 1. The sealing structure 372 may be formed of a plastic material such as a synthetic resin, or may be formed of an O-ring. Although the module body 700B and the container 1 in FIG. 20A are separate bodies, the piezoelectric device mounting portion of the module body 700B may be configured as a part of the container 1 as shown in FIG.

  The module 700B in FIG. 20A does not require the lead wires shown in FIGS. 14 to 18 to be embedded in the module. Therefore, the molding process is simplified. Furthermore, the module body 700B can be replaced and recycled.

  When the ink cartridge is shaken, the ink adheres to the upper surface or the side surface of the container 1, and the ink dripping from the upper surface or the side surface of the container 1 may contact the actuator 106, so that the actuator 106 may malfunction. However, in the module 700B, since the liquid container mounting portion 360 protrudes inside the container 1, the actuator 106 does not malfunction due to ink dripping from the upper surface or side surface of the container 1.

  In the embodiment of FIG. 20A, only a part of the vibration plate 176 and the mounting plate 350 is attached to the container 1 so as to come into contact with the ink in the container 1. In the embodiment of FIG. 20A, it is not necessary to embed the electrodes of the lead wires 104a, 104b, 404a, 404b, 504a, and 504b shown in FIGS. 14 to 18 in the module body. Therefore, the molding process is simplified. Furthermore, the actuator 106 can be replaced and recycled.

  FIG. 20B shows a cross-sectional view of an ink container as an example when the actuator 106 is mounted on the container 1. In the ink cartridge according to the embodiment of FIG. 20B, the protection member 361 is attached to the container 1 as a separate body from the actuator 106. Therefore, although the protection member 361 and the actuator 106 are not integrated as a module, the protection member 361 can protect the actuator 106 from being touched by the user's hand. A hole 380 provided in the front surface of the actuator 106 is disposed on the side wall of the container 1. The actuator 106 includes a piezoelectric layer 160, an upper electrode 164, a lower electrode 166, a vibration plate 176, and a mounting plate 350. A vibration plate 176 is formed on the upper surface of the mounting plate 350, and a lower electrode 166 is formed on the upper surface of the vibration plate 176. A piezoelectric layer 160 is formed on the upper surface of the lower electrode 166, and an upper electrode 164 is formed on the upper surface of the piezoelectric layer 160. Accordingly, the main part of the piezoelectric layer 160 is formed so as to be sandwiched from above and below by the main part of the upper electrode 164 and the main part of the lower electrode 166. The circular portions that are the main parts of the piezoelectric layer 160, the upper electrode 164, and the lower electrode 166 form a piezoelectric element. The piezoelectric element is formed on the vibration plate 176. The vibration region of the piezoelectric element and the diaphragm 176 is a vibration part where the actuator actually vibrates. A through hole 370 is provided in the mounting plate 350. Further, a hole 380 is formed in the side wall of the container 1. Therefore, the ink contacts the vibration plate 176 through the hole 380 of the container 1 and the through hole 370 of the mounting plate 350. The hole 380 of the container 1 and the through hole 370 of the mounting plate 350 together form an ink reservoir. In the embodiment of FIG. 20B, the actuator 106 is protected by the protective member 361, so that the actuator 106 can be protected from contact with the outside.

  Note that the substrate 178 of FIG. 1 may be used in place of the mounting plate 350 in the embodiment of FIGS.

  FIG. 20C shows an embodiment including a mold structure 600 including the actuator 106. In this embodiment, a mold structure 600 is used as one of the attachment structures. The mold structure 600 includes an actuator 106 and a mold part 364. The actuator 106 and the mold part 364 are integrally formed. The mold part 364 is formed of a plastic material such as silicon resin. The mold part 364 has a lead wire 362 inside. Mold portion 364 is formed to have two legs extending from actuator 106. In order to fix the mold part 364 and the container 1 in a liquid-tight manner, the mold part 364 has two hemispherical ends of the mold part 364. The mold part 364 is mounted on the container 1 so that the actuator 106 protrudes into the container 1, and the vibration part of the actuator 106 contacts the ink in the container 1. The mold part 364 protects the upper electrode 164, the piezoelectric layer 160, and the lower electrode 166 of the actuator 106 from ink.

  The mold structure 600 in FIG. 20C does not require the sealing structure 372 between the mold part 364 and the container 1, so that ink is unlikely to leak from the container 1. In addition, since the mold structure 600 does not protrude from the outside of the container 1, the actuator 106 can be protected from contact with the outside. When the ink cartridge is shaken, the ink adheres to the upper surface or the side surface of the container 1, and the ink dripping from the upper surface or the side surface of the container 1 contacts the actuator 106, so that the actuator 106 may malfunction. . In the mold structure 600, since the mold part 364 protrudes inside the container 1, the actuator 106 does not malfunction due to the ink dripping from the upper surface or side surface of the container 1.

  FIG. 21 shows an embodiment of an ink cartridge and an ink jet recording apparatus using the actuator 106 shown in FIG. The plurality of ink cartridges 180 are attached to an ink jet recording apparatus having a plurality of ink introduction portions 182 and holders 184 corresponding to the respective ink cartridges 180. The plurality of ink cartridges 180 accommodate different types of ink, for example, colors. On the bottom surface of each of the plurality of ink cartridges 180, an actuator 106 that is a means for detecting at least acoustic impedance is mounted. By mounting the actuator 106 on the ink cartridge 180, the remaining amount of ink in the ink cartridge 180 can be detected.

  FIG. 22 shows details of the vicinity of the head portion of the ink jet recording apparatus. The ink jet recording apparatus includes an ink introduction unit 182, a holder 184, a head plate 186, and a nozzle plate 188. A plurality of nozzles 190 for ejecting ink are formed on the nozzle plate 188. The ink introduction part 182 has an air supply port 181 and an ink introduction port 183. The air supply port 181 supplies air to the ink cartridge 180. The ink introduction port 183 introduces ink from the ink cartridge 180. The ink cartridge 180 has an air introduction port 185 and an ink supply port 187. The air introduction port 185 introduces air from the air supply port 181 of the ink introduction unit 182. The ink supply port 187 supplies ink to the ink introduction port 183 of the ink introduction unit 182. When the ink cartridge 180 introduces air from the ink introduction part 182, the supply of ink from the ink cartridge 180 to the ink introduction part 182 is promoted. The holder 184 communicates the ink supplied from the ink cartridge 180 via the ink introduction unit 182 to the head plate 186.

  FIG. 23 shows another embodiment of the ink cartridge 180 shown in FIG. In the ink cartridge 180A in FIG. 23A, the actuator 106 is mounted on a bottom surface 194a formed obliquely in the vertical direction. Inside the ink container 194 of the ink cartridge 180, a wave barrier 192 is provided at a position facing the actuator 106 at a predetermined height from the inner bottom surface of the ink container 194. Since the actuator 106 is mounted obliquely with respect to the vertical direction of the ink container 194, the ink can be swept well.

  A gap filled with ink is formed between the actuator 106 and the wave barrier 192. Further, the gap between the wave preventing wall 192 and the actuator 106 is set to such an extent that the ink is not retained by the capillary force. When the ink container 194 rolls, an ink wave is generated inside the ink container 194 due to the roll, and due to the impact, gas or bubbles may be detected by the actuator 106 and the actuator 106 may malfunction. By providing the wave preventing wall 192, ink waves near the actuator 106 can be prevented, and malfunction of the actuator 106 can be prevented.

  The actuator 106 of the ink cartridge 180B of FIG. 23B is mounted on the side wall of the supply port of the ink container 194. The actuator 106 may be mounted on the side wall or bottom surface of the ink container 194 as long as it is near the ink supply port 187. The actuator 106 is preferably mounted at the center of the ink container 194 in the width direction. Since the ink passes through the ink supply port 187 and is supplied to the outside, providing the actuator 106 in the vicinity of the ink supply port 187 ensures that the ink and the actuator 106 come into contact until the ink near end point. Therefore, the actuator 106 can reliably detect the time point of the ink near end.

  Further, by providing the actuator 106 in the vicinity of the ink supply port 187, the positioning of the actuator 106 on the ink container and the contact on the carriage is ensured when the ink container is mounted on the cartridge holder on the carriage. The reason is that the most important in the connection between the ink container and the carriage is a reliable connection between the ink supply port and the supply needle. This is because even if there is a slight deviation, the tip of the supply needle is damaged, or the sealing structure such as the O-ring is damaged and the ink leaks out. In order to prevent such problems, an ink jet printer usually has a special structure that allows accurate alignment when an ink container is mounted on a carriage. Therefore, by arranging the actuator in the vicinity of the supply port, the alignment of the actuator can be ensured at the same time. Furthermore, by mounting the actuator 106 at the center in the width direction of the ink container 194, the alignment can be performed more reliably. This is because, when the ink container swings about the center line in the width direction when mounted on the holder, the vibration is least.

  FIG. 24 shows still another embodiment of the ink cartridge 180. 24A is a cross-sectional view of the ink cartridge 180C, FIG. 24B is an enlarged cross-sectional view of the side wall 194b of the ink cartridge 180C shown in FIG. 24A, and FIG. FIG. In the ink cartridge 180C, the semiconductor storage means 7 and the actuator 106 are formed on the same circuit board 610. As shown in FIGS. 24B and 24C, the semiconductor memory means 7 is formed above the circuit board 610, and the actuator 106 is formed below the semiconductor memory means 7 on the same circuit board 610. Atypical O-ring 614 is attached to side wall 194b so as to surround actuator 106. A plurality of crimping portions 616 for joining the circuit board 610 to the ink container 194 are formed on the side wall 194b. The caulking portion 616 joins the circuit board 610 to the ink container 194, and presses the odd-shaped O-ring 614 against the circuit board 610, so that the vibration region of the actuator 106 can come into contact with the ink, and the outside of the ink cartridge. Keep inside and fluid tight.

  Terminals 612 are formed near the semiconductor memory means 7 and the semiconductor memory means 7. A terminal 612 exchanges signals between the semiconductor storage means 7 and the outside of the inkjet storage device or the like. The semiconductor memory means 7 may be constituted by a rewritable semiconductor memory such as an EEPROM. Since the semiconductor storage means 7 and the actuator 106 are formed on the same circuit board 610, a single attachment process is sufficient when the actuator 106 and the semiconductor storage means 7 are attached to the ink cartridge 180C. Further, the work process at the time of manufacturing and recycling the ink cartridge 180C is simplified. Furthermore, since the number of parts is reduced, the manufacturing cost of the ink cartridge 180C can be reduced.

  The actuator 106 detects the ink consumption state in the ink container 194. The semiconductor storage means 7 stores ink information such as the remaining ink amount detected by the actuator 106. In other words, the semiconductor storage means 7 stores information relating to characteristic parameters such as the characteristics of ink and ink cartridges used for detection. The semiconductor storage unit 7 is configured to resonate when the ink in the ink container 194 is full, that is, when the ink is filled in the ink container 194, or at the end, that is, when the ink in the ink container 194 is consumed. Store the frequency as one of the characteristic parameters. The resonance frequency when the ink in the ink container 194 is full or in an end state may be stored when the ink container is first attached to the ink jet recording apparatus. Further, the resonance frequency when the ink in the ink container 194 is full or in an end state may be stored during the manufacture of the ink container 194. The semiconductor storage unit 7 stores in advance the resonance frequency when the ink in the ink container 194 is full or end, and reads the resonance frequency data on the ink jet recording apparatus side to correct variations when detecting the remaining amount of ink. Therefore, it is possible to accurately detect that the remaining ink amount has decreased to the reference value.

  FIG. 25 shows still another embodiment of the ink cartridge 180. An ink cartridge 180D shown in FIG. 25A has a plurality of actuators 106 mounted on the side wall 194b of the ink container 194. A plurality of integrally formed actuators 106 shown in FIG. 5 are preferably used as the plurality of actuators 106. The plurality of actuators 106 are arranged on the side wall 194b at intervals in the vertical direction. By disposing a plurality of actuators 106 on the side wall 194b at intervals in the vertical direction, the remaining amount of ink can be detected stepwise.

  In an ink cartridge 180E shown in FIG. 25B, an actuator 606 that is long in the vertical direction is mounted on the side wall 194b of the ink container 194. A change in the remaining amount of ink in the ink container 194 can be continuously detected by the actuator 606 that is long in the vertical direction. The length of the actuator 606 is preferably half or more of the height of the side wall 194b. In FIG. 25B, the actuator 606 has a length from the upper end to the lower end of the side wall 194b.

  In the ink cartridge 180F shown in FIG. 25C, similarly to the ink cartridge 180D shown in FIG. 25A, a plurality of actuators 106 are mounted on the side wall 194b of the ink container 194 so A wave barrier 192 that is long in the vertical direction is provided. A plurality of integrally formed actuators 106 shown in FIG. 5 are preferably used as the plurality of actuators 106. A gap filled with ink is formed between the actuator 106 and the wave barrier 192. Further, the gap between the wave preventing wall 192 and the actuator 106 is set to such an extent that the ink is not retained by the capillary force. When the ink container 194 rolls, a wave of ink is generated inside the ink container 194 due to the roll, and gas or bubbles are detected by the actuator 106 due to the impact, and the actuator 106 may malfunction. By providing the wave preventing wall 192 as in the present invention, it is possible to prevent the ink from flowing near the actuator 106 and prevent the actuator 106 from malfunctioning. Further, the wave preventing wall 192 prevents bubbles generated by the ink swinging from entering the actuator 106.

  FIG. 26 shows still another embodiment of the ink cartridge 180. The ink cartridge 180G in FIG. 26A includes a plurality of partition walls 212 extending downward from the upper surface 194c of the ink container 194. Since the lower end of each partition wall 212 and the bottom surface of the ink container 194 are spaced apart from each other, the bottom of the ink container 194 communicates. The ink cartridge 180G has a plurality of storage chambers 213 defined by a plurality of partition walls 212, respectively. The bottoms of the plurality of storage chambers 213 communicate with each other. In each of the plurality of storage chambers 213, the actuator 106 is mounted on the upper surface 194 c of the ink container 194. The integrally formed actuator 106 shown in FIG. 5 is preferably used as the plurality of actuators 106. The actuator 106 is disposed approximately at the center of the upper surface 194 c of the storage chamber 213 of the ink container 194. The capacity of the storage chamber 213 is the largest on the ink supply port 187 side, and the capacity of the storage chamber 213 gradually decreases as the ink supply port 187 moves away from the ink container 194. Therefore, the interval at which the actuator 106 is disposed is wide on the ink supply port 187 side, and becomes narrower as the distance from the ink supply port 187 to the back of the ink container 194 increases.

  Since the ink is discharged from the ink supply port 187 and air enters from the air introduction port 185, the ink is consumed from the storage chamber 213 on the ink supply port 187 side to the storage chamber 213 at the back of the ink cartridge 180G. For example, while the ink in the storage chamber 213 closest to the ink supply port 187 is consumed and the water level of the ink in the storage chamber 213 closest to the ink supply port 187 is lowered, the other storage chamber 213 is filled with ink. ing. When the ink in the storage chamber 213 closest to the ink supply port 187 is consumed, air enters the second storage chamber 213 counted from the ink supply port 187 and the ink in the second storage chamber 213 is consumed. For the first time, the ink level in the second storage chamber 213 begins to drop. At this time, the third and subsequent storage chambers 213 counted from the ink supply chamber 187 are filled with ink. In this way, ink is consumed in order from the storage chamber 213 close to the ink supply port 187 to the storage chamber 213 far away.

  As described above, since the actuator 106 is arranged at an interval on the upper surface 194c of the ink container 194 for each of the storage chambers 213, the actuator 106 can detect a decrease in the ink amount in stages. Further, since the capacity of the storage chamber 213 gradually decreases from the ink supply port 187 to the back of the storage chamber 213, the time interval at which the actuator 106 detects a decrease in the ink amount gradually decreases, and the ink end The frequency can be detected higher as the value approaches.

  The ink cartridge 180H in FIG. 26B has one partition wall 212 extending downward from the upper surface 194c of the ink container 194. Since the lower end of the partition wall 212 and the bottom surface of the ink container 194 are spaced apart from each other, the bottom of the ink container 194 is in communication. The ink cartridge 180H has two storage chambers 213a and 213b divided by a partition wall 212. The bottoms of the storage chambers 213a and 213b communicate with each other. The capacity of the storage chamber 213a on the ink supply port 187 side is larger than the capacity of the storage chamber 213b at the back as viewed from the ink supply port 187. The capacity of the storage chamber 213b is preferably smaller than half of the capacity of the storage chamber 213a.

  The actuator 106 is mounted on the upper surface 194c of the storage chamber 213b. Further, the storage chamber 213b is formed with a buffer 214, which is a groove for catching air bubbles entering when the ink cartridge 180H is manufactured. In FIG. 26B, the buffer 214 is formed as a groove extending upward from the side wall 194 b of the ink container 194. Since the buffer 214 captures the bubbles that have entered the ink storage chamber 213b, the malfunction that the actuator 106 detects as the ink end due to the bubbles can be prevented. Further, by providing the actuator 106 on the upper surface 194c of the storage chamber 213b, the ink amount in the storage chamber 213a grasped by the dot counter can be determined with respect to the ink amount from the detection of the ink near end to the complete ink end state. By applying correction corresponding to the consumption state, ink can be consumed to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.

  In FIG. 26C, a porous member 216 is filled in the accommodation chamber 213b of the ink cartridge 180I in FIG. The porous member 216 is installed so as to fill the entire space from the upper surface to the lower surface in the accommodation chamber 213b. The porous member 216 is in contact with the actuator 106. When the ink container falls down or during reciprocation on the carriage, air may enter the ink storage chamber 213b, which may cause the actuator 106 to malfunction. However, if the porous member 216 is provided, air can be trapped and air can be prevented from entering the actuator 106. In addition, since the porous member 216 holds ink, the ink container is shaken, so that it is possible to prevent the ink from being applied to the actuator 106 and causing the actuator 106 to erroneously detect that there is no ink. The porous member 216 is preferably installed in the storage chamber 213 having the smallest capacity. Further, by providing the actuator 106 on the upper surface 194c of the storage material 213b, it is possible to correct the ink amount from the detection of the ink near end to the complete ink end state, and to consume the ink to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.

  FIG. 26D shows an ink cartridge 180J in which the porous member 216 of the ink cartridge 180I of FIG. 26C is configured by two types of porous members 216A and 216B having different hole diameters. The porous member 216A is disposed above the porous member 216B. The hole diameter of the upper porous member 216A is larger than the hole diameter of the lower porous member 216B. Alternatively, the porous member 216A is formed of a member having a lower liquid affinity than the porous member 216B. Since the porous member 216B having a smaller pore diameter has a larger capillary force than the porous member 216A having a larger pore diameter, the ink in the storage chamber 213b is collected and held in the lower porous chamber member 216B. Therefore, once the air reaches the actuator 106 and the absence of ink is detected, the ink never reaches the actuator again to detect the presence of ink. Further, the ink is absorbed by the porous member 216B on the side far from the actuator 106, so that the ink in the vicinity of the actuator 106 is improved, and the amount of change in the acoustic impedance change when detecting the presence or absence of ink increases. Further, by providing the actuator 106 on the upper surface 194c of the storage material 213b, it is possible to correct the ink amount from the detection of the ink near end to the complete ink end state, and to consume the ink to the end. Furthermore, by adjusting the capacity of the storage chamber 213b by changing the length or interval of the partition wall 212, the amount of ink that can be consumed after ink near-end detection can be changed.

  FIG. 27 is a cross-sectional view showing an ink cartridge 180K, which is another embodiment of the ink cartridge 180I shown in FIG. The porous member 216 of the ink cartridge 180 shown in FIG. 27 is compressed so that the horizontal cross-sectional area of the lower portion of the porous member 216 gradually decreases toward the bottom surface of the ink container 194, and the pore diameter is small. Designed to be Ink cartridge 180K in FIG. 27A is provided with ribs on the side walls in order to compress the hole diameter on the lower side of porous member 216 to be small. Since the pore diameter at the bottom of the porous member 216 is reduced by being compressed, the ink is collected and held at the bottom of the porous member 216. Ink is absorbed by the lower portion of the porous member 216 far from the actuator 106, so that the ink in the vicinity of the actuator 106 is improved, and the amount of change in the acoustic impedance change when detecting the presence or absence of ink increases. Therefore, the ink is applied to the actuator 106 mounted on the upper surface of the ink cartridge 180K due to the shaking of the ink, and the actuator 106 can be prevented from erroneously detecting that no ink is present.

  On the other hand, in the ink cartridge 180L of FIGS. 27B and 27C, the horizontal cross-sectional area of the lower portion of the porous member 216 gradually increases toward the bottom surface of the ink container 194 in the width direction of the ink container 194. In order to compress the ink container so as to be smaller, the horizontal sectional area of the storage chamber gradually decreases toward the bottom surface of the ink container 194. Since the pore diameter at the bottom of the porous member 216 is reduced by being compressed, the ink is collected and held at the bottom of the porous member 216. Ink is absorbed in the lower portion of the porous member 216B far from the actuator 106, so that ink near the actuator 106 is improved, and the amount of change in acoustic impedance change when detecting the presence or absence of ink increases. Therefore, when the ink shakes, ink is applied to the actuator 106 mounted on the upper surface of the ink cartridge 180L, and the actuator 106 can be prevented from erroneously detecting that no ink is present.

  FIG. 28 shows still another embodiment of the ink cartridge using the actuator 106. The ink cartridge 220A shown in FIG. 28A has a first partition 222 provided so as to extend downward from the upper surface of the ink cartridge 220A. Since a predetermined gap is provided between the lower end of the first partition 222 and the bottom surface of the ink cartridge 220A, ink can flow into the ink supply port 230 through the bottom surface of the ink cartridge 220A. A second partition 224 is formed on the ink supply port 230 side from the first partition 222 so as to extend upward from the bottom surface of the ink cartridge 220A. Since a predetermined gap is provided between the upper end of the second partition 224 and the upper surface of the ink cartridge 220A, ink can flow into the ink supply port 230 through the upper surface of the ink cartridge 220A.

  A first storage chamber 225 a is formed in the back of the first partition 222 when viewed from the ink supply port 230 by the first partition 222. On the other hand, the second partition 224 forms a second storage chamber 225 b on the front side of the second partition 224 when viewed from the ink supply port 230. The capacity of the first storage chamber 225a is larger than the capacity of the second storage chamber 225b. Capillary passages 227 are formed by providing a gap between the first partition 222 and the second partition 224 to allow capillary action. Therefore, the ink in the first storage chamber 225 a is collected in the capillary passage 227 by the capillary force of the capillary passage 227. Therefore, it is possible to prevent gas or bubbles from entering the second storage chamber 225b. Further, the water level of the ink in the second storage chamber 225b can be gradually and stably lowered. Since the first storage chamber 225a is formed behind the second storage chamber 225b when viewed from the ink supply port 230, after the ink in the first storage chamber 225a is consumed, the second storage chamber 225b of ink is consumed.

  The actuator 106 is attached to the side wall of the ink cartridge 220A on the ink supply port 230 side, that is, the side wall of the second storage chamber 225b on the ink supply port 230 side. The actuator 106 detects the ink consumption state in the second storage chamber 225b. By mounting the actuator 106 on the side wall of the second storage chamber 225b, it is possible to stably detect the remaining amount of ink at a point closer to the ink end. Furthermore, by changing the height at which the actuator 106 is mounted on the side wall of the second storage chamber 225b, it is possible to freely set at which point the remaining amount of ink is used as the ink end. Since the ink is supplied from the first storage chamber 225a to the second storage chamber 225b by the capillary passage 227, the actuator 106 is not affected by the roll of the ink due to the roll of the ink cartridge 220A. Can reliably measure the remaining amount of ink. Furthermore, since the capillary passage 227 holds the ink, the ink is prevented from flowing back from the second storage chamber 225b to the first storage chamber 225a.

  A check valve 228 is provided on the upper surface of the ink cartridge 220A. The check valve 228 can prevent ink from leaking outside the ink cartridge 220A when the ink cartridge 220A rolls. Further, by installing the check valve 228 on the upper surface of the ink cartridge 220A, it is possible to prevent ink from evaporating from the ink cartridge 220A. When the ink in the ink cartridge 220A is consumed and the negative pressure in the ink cartridge 220A exceeds the pressure of the check valve 228, the check valve 228 is opened, air is sucked into the ink cartridge 220A, and then the ink is closed and the ink is closed. The pressure in the cartridge 220A is kept constant.

  28C and 28D show a detailed cross section of the check valve 228. The check valve 228 of FIG. 28C has a valve 232 having a blade 232a formed of rubber. A ventilation hole 233 for the outside of the ink cartridge 220 is provided in the ink cartridge 220 so as to face the blade 232a. The air hole 233 is opened and closed by the blade 232a. When the ink in the ink cartridge 220 decreases and the negative pressure in the ink cartridge 220 exceeds the pressure of the check valve 228, the check valve 228 opens the blade 232 a to the inside of the ink cartridge 220 and removes external air. The ink cartridge 220 is taken in. A check valve 228 in FIG. 28D includes a valve 232 and a spring 235 formed of rubber. When the negative pressure in the ink cartridge 220 exceeds the pressure of the check valve 228, the check valve 228 opens the spring 235 by pressing the spring 235, and sucks outside air into the ink cartridge 220 and then closes. Thus, the negative pressure in the ink cartridge 220 is kept constant.

  In the ink cartridge 220B of FIG. 28B, a porous member 242 is disposed in the first storage chamber 225a instead of providing the check valve 228 in the ink cartridge 220A of FIG. The porous member 242 holds the ink in the ink cartridge 220B and prevents the ink from leaking out of the ink cartridge 220B when the ink cartridge 220B rolls.

  As described above, the ink cartridge mounted on the carriage is separated from the carriage, and the ink cartridge or the actuator 106 is mounted on the carriage. However, the ink is integrated with the carriage and mounted on the inkjet recording apparatus together with the carriage. The actuator 106 may be attached to the tank. Further, the actuator 106 may be mounted on an off-carriage type ink tank that supplies ink to the carriage via a tube or the like that is separate from the carriage. Furthermore, the actuator of the present invention may be attached to an ink cartridge that is configured so that the recording head and the ink container are integrated and replaceable.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

FIG. 4 is a diagram showing details of an actuator 106. It is a figure which shows the periphery of the actuator 106 and its equivalent circuit. FIG. 5 is a diagram illustrating a relationship between ink density and ink resonance frequency detected by an actuator. FIG. 4 is a diagram illustrating a relationship between a remaining amount of ink in an ink cartridge and a combination pattern in a primary mode and a secondary mode of a resonance frequency. It is a figure which shows the back electromotive force waveform of the actuator. It is a figure which shows other embodiment of the actuator. It is a figure which shows the cross section of a part of actuator 106 shown in FIG. It is a figure which shows the cross section of the whole actuator 106 shown in FIG. It is a figure which shows the manufacturing method of the actuator shown in FIG. It is a figure which shows other embodiment of the ink cartridge of this invention. It is a figure which shows other embodiment of the through-hole 1c. It is a figure which shows other embodiment of the actuator 660. FIG. FIG. 38 is a diagram showing still another embodiment of the actuator 670. 2 is a perspective view showing a module body 100. FIG. It is an exploded view which shows the structure of the module body 100 shown in FIG. It is a figure which shows other embodiment of the module body. It is an exploded view which shows the structure of the module body 100 shown in FIG. It is a figure which shows other embodiment of the module body. FIG. 15 is a diagram illustrating an example of a cross section in which the module body 100 illustrated in FIG. It is a figure which shows other embodiment of the module body. FIG. 3 is a diagram showing an embodiment of an ink cartridge and an ink jet recording apparatus using the actuator shown in FIGS. 1 and 2. It is a figure which shows the detail of an inkjet recording device. It is a figure which shows other embodiment of the ink cartridge 180 shown in FIG. FIG. 10 is a view showing still another embodiment of the ink cartridge 180. FIG. 10 is a view showing still another embodiment of the ink cartridge 180. FIG. 10 is a view showing still another embodiment of the ink cartridge 180. FIG. 27 is a diagram showing another embodiment of the ink cartridge 180 shown in FIG. FIG. 10 is a view showing still another embodiment of an ink cartridge using the module body 100.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container 1a ... Bottom 1b ... Side wall 1c, 940a ... Through-hole 1d, ... Side 1e, 1f ... Step part 1g, 1h ... Groove 2 ... Ink supply Port 67 ... Plate material 68 ... Float 71 ... Adhesive layer 72, 80, 178 ... Substrate 73, 82, Piezoelectric vibration plate 74, 75 ... Ink absorber 76 ... Packing 77 ···················································································· 100 505: Piezoelectric device mounting portion 106, 650, 660, 670 ... Actuator 108 ... Film 110 ... Plate 112, 412, 370 ... Through hole 113 ... Recess 114 ... Opening Part 116 · Cylindrical portion 160 ··· piezoelectric layer 162 ··· cavity 164 ··· upper electrode 166 ··· lower electrode 168 · · · upper electrode terminal 170 ··· lower electrode terminal 172 ··· auxiliary electrode 174 ··· Piezoelectric element 176 ... diaphragm 180 ... ink cartridge 181 ... air supply port 182 ... ink inlet 183 ... ink inlet 184 ... holder 185 ... air inlet 186 ... Head plate 187 ... Ink supply port 188 ... Nozzle plate 190 ... Nozzle 192 ... Wave barrier 194 ... Ink container 194a ... Bottom 194b ... Side wall 194c ... Top 212 ... partition walls 213, 213a, 213b ... storage chamber 214 ... buffer 216, 216a, 216b ... porous member 220 ... ink cart Wedge 222 ... first partition 224 ... second partition 225a ... first storage chamber 225b ... second storage chamber 227 ... capillary passage 228 ... check valve 230 ... Ink supply port 232 ... Valve 232a ... Blade 233 ... Vent hole 235 ... Spring 242 ... Porous member 250 ... Carriage 252 ... Recording head 254 ... Ink Supply needle 256 ... sub tank unit 258,258 '... convex 260,260' ... elastic wave generating means 262 ... ink chamber 266 ... membrane valve 270 ... valve element 272 ... Ink cartridge 274 ... Container 274a ... Bottom 274b ... Side 276 ... Ink supply port 278 ... Recess 280, 280 '... Gelling material 282 ... Packing 284 ... Spring 286 ... Valve 288 ... Semiconductor storage means 290 ... container 290a ... bottom surface 292,294,296 ... ink chambers 298,300,302 ... ink supply ports 304,306,308 ... gel material 310, 312, 314, recess 316, plate 318, float 350, mounting plate 360, liquid container mounting portion 364, mold portion 372, sealing structure 402, 502, base Tables 403, 503 ... Cylinder portions 404, 504 ... Lead wires 408, 508 ... Films 410, 510 ... Plates 413, 513 ... Recesses 414, 514 ... Openings 600 ... Mold structure 606 ... Actuator 610 ... Circuit board 612 ... Terminals 940, 941 ... Green sheets 942, 944 ... Conductive 944 '... connecting portion 947,948 ... spacer member Delta] hl, [Delta] h2 change in ... liquid level K ... Ink

Claims (11)

A liquid consumption state detection method for detecting a consumption state of a liquid in the liquid container by detecting residual vibration generated in a piezoelectric device attached to the liquid container, wherein the piezoelectric element of the piezoelectric device is driven to drive the piezoelectric device. By oscillating the vibration part of the apparatus and then detecting vibration frequencies of a plurality of resonance modes of residual vibration of the vibration part after a predetermined interval using the piezoelectric element, the consumption state of the liquid The liquid consumption state detection method characterized by detecting.   The liquid consumption state detection method according to claim 1, wherein the consumption state of the liquid in the liquid container is detected by detecting a frequency of residual vibration generated in the piezoelectric device.   The liquid consumption state detection method according to claim 1, wherein the piezoelectric device detects a liquid consumption state in the liquid container by detecting a resonance frequency of a liquid around the device.   The liquid consumption state detection method according to claim 1, wherein after the piezoelectric device is driven, the liquid consumption state is detected after the piezoelectric device vibrates a predetermined number of times.   The liquid consumption state detection method according to claim 1, wherein a vibration frequency at which the piezoelectric device vibrates is a frequency in a non-audible region.   The consumption state is detected using the frequency by calculating a frequency of the residual vibration by measuring a time between a plurality of predetermined peaks of the residual vibration of the piezoelectric device. Liquid consumption state detection method.   The frequency of the residual vibration is calculated by measuring the number of peaks of the residual vibration of the piezoelectric device within a predetermined time, and a consumption state is detected using the frequency. Liquid consumption state detection method.   The liquid consumption state detection method according to claim 1, wherein the liquid consumption state is detected by measuring a voltage level of a counter electromotive force generated by residual vibration of the piezoelectric device.   Using the measurement value of the vibration frequency of the residual vibration when the liquid in the liquid container is full as a reference value, the measurement value of the vibration frequency of the residual vibration in the process in which the liquid in the liquid container is consumed is compared. The liquid consumption state detection method according to claim 1, wherein the liquid consumption state is determined. The vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode of the residual vibration of the piezoelectric device are detected, and the vibration frequency of the first resonance mode and the vibration frequency of the second resonance mode are set to 1. The liquid consumption state detection method according to claim 1 , wherein the liquid consumption state detection method is recognized as one pattern.   The liquid consumption state detection method according to claim 1, wherein the liquid container is an ink cartridge used in an ink jet recording apparatus.

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