CN1748127A - Consumables container that can measure the remaining amount of consumables - Google Patents

Abstract

The present invention is a consumable product container capable of measuring the remaining amount of the contained consumable product. The consumable product container includes: a consumable product tank for accommodating the consumable product and installing a piezoelectric element; a detection signal generating circuit for charging and discharging the piezoelectric element and generating a detection signal, the detection signal information indicating a period of residual vibration after the piezoelectric element is discharged; and a control unit for controlling charging and discharging of the piezoelectric element. It is characterized in that the cycle can be used to determine whether the remaining amount of the contained consumables is more than a predetermined amount; the control unit can change the discharge characteristic of the piezoelectric element.

Description

Consumables container that can measure the remaining amount of consumables

technical field

The present invention relates to a technique for measuring the remaining amount of a consumable in a consumable container.

Background technique

In recent years, inkjet printers have become popular as output devices for computers. In general, ink for an inkjet printer that is a consumable is supplied by being accommodated in an ink cartridge. As a method of measuring the remaining amount of consumables contained in an ink cartridge, for example, a method of direct measurement using a piezoelectric element is proposed as disclosed in Japanese Patent Application Laid-Open No. 2001-147146.

In this method, first, the vibrating portion of the piezoelectric element is vibrated by applying a voltage wave to the piezoelectric element mounted in the ink cartridge. Next, the remaining amount of consumables is measured from the periodic variation of the counter electromotive force generated by the residual vibration remaining on the vibrating portion of the piezoelectric element.

However, there arises a problem in this method that the S/N ratio is often lowered due to unintentional vibration noise, so that it cannot be measured correctly. On the other hand, manually adjusting the circuit of each ink cartridge in order to improve the S/N ratio would cause a heavy load. Such a problem is not limited to ink cartridges, but is generally a problem common to consumable product containers that can measure the remaining amount of consumable products using piezoelectric elements.

Contents of the invention

The present invention is made to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a technique for improving the reliability of measurement in a consumable container that can measure the remaining amount of consumables using piezoelectric elements.

The consumables container according to the first aspect of the present invention is a consumables container capable of measuring the remaining amount of the contained consumables. The consumable product container includes: a consumable product tank for accommodating the consumable product and having a piezoelectric element installed therein; a detection signal generation circuit for charging and discharging the piezoelectric element and generating a detection signal, the The detection signal includes information indicating a period of residual vibration after the piezoelectric element is discharged; and the control unit is configured to control charging and discharging of the piezoelectric element. In the consumable product container, the cycle may be used to determine whether the remaining amount of the stored consumable product is more than a predetermined amount; and the control unit may change the discharge characteristic of the piezoelectric element.

In the consumables container according to the first aspect of the present invention, since the discharge characteristics of the piezoelectric element can be changed, the characteristics of residual vibration after discharge can be changed to ideal characteristics for remaining amount detection. Thereby, the reliability of measurement can be improved. Here, the term "piezoelectric element" refers to an element having two characteristics of an inverse piezoelectric effect that deforms according to charging and discharging, and a piezoelectric effect that generates voltage due to deformation.

In the consumables container described above, a configuration may be adopted in which the control unit can change the discharge time constant of the piezoelectric element, and the control unit can change the discharge time of the piezoelectric element. Here, the so-called discharge time refers to the time when the switch connected between the piezoelectric element and the ground is closed to be in the conduction state.

In the consumables container described above, the detection signal generating circuit may be configured as follows, including: a voltage generating circuit for generating a predetermined potential difference between the first terminal on the high potential side and the second terminal on the low potential side a piezoelectric element, one end of which is connected to the second terminal; a charging control switch, connected between the first terminal and the other end of the piezoelectric element, for controlling output from the control unit , to switch control the charging from the first terminal to the piezoelectric element; a discharge control switch, connected between the other end of the piezoelectric element and the second terminal, for controlling The control output of the part is used to switch and control the discharge from the piezoelectric element to the second terminal; the resistance circuit is a circuit connected between the other end of the piezoelectric element and the second terminal, and The resistance value may be changed; wherein the control unit performs on-off control of the charge control switch, on-off control of the discharge control switch, and control of the resistance value of the resistance circuit.

The method of the present invention is a method of measuring the remaining amount of consumables in the consumables container. The method includes: (a) the steps of preparing a consumable canister for accommodating the consumable and mounting the piezoelectric element, and a circuit for charging and discharging the piezoelectric element; (b) variably setting the a step of describing the discharge characteristic of the piezoelectric element; (c) a step of performing said measurement. In the method, it is characterized in that the step (c) includes: (c-1) a step of charging the piezoelectric element; (c-2) a step of discharging the piezoelectric element; (c- 3) A step of generating a detection signal, wherein the detection signal includes information representing a cycle of residual vibration after the piezoelectric element is discharged; (c-4) determining the stored consumables in response to the detection signal Whether the remaining amount is more than the predetermined amount.

In the above method, the step (c) preferably further includes: in response to the detection signal, judging whether the remaining amount of the stored consumable can be measured, and in response to judging that the measurement is not possible, setting Processing returns to said step (b), wherein said step (b) preferably includes: in response to a determination that said measurement is not possible, setting said discharge characteristic to be equal to said The measured discharge characteristic is different from the discharge characteristic, and the process proceeds to the step of the step (c).

In this way, since the discharge characteristic capable of measuring the remaining amount of ink can be automatically set and the measurement can be performed with this setting, the reliability of the measurement can be improved.

In the above method, it is preferable to further include: (d) a step of preparing a nonvolatile memory; and (e) a step of recording setting information in said memory, wherein said setting information represents The setting content of the set discharge characteristic; and, the step (b) preferably includes: a step of setting the discharge characteristic based on the setting information read from the nonvolatile memory.

In this way, since the information indicating the discharge characteristic set at the last measurement can be stored in the memory, and the measurement can be performed with the stored setting, the possibility of measuring without changing the setting of the discharge characteristic can be improved.

The manufacturing method according to the first aspect of the present invention is a method of manufacturing a consumable product container capable of measuring the remaining amount of the contained consumable product. The method includes: (a) a step of measuring a characteristic of the piezoelectric element and generating piezoelectric element characteristic information representing the characteristic of the piezoelectric element; (b) a step of preparing a consumable canister for storing the consumable ; (c) a step of mounting the piezoelectric element, detection signal generating circuit, and nonvolatile memory on the consumables tank, wherein the detection signal generating circuit performs charging and discharging of the piezoelectric element, and generating a detection signal, the detection signal including information representing the period of the residual vibration after the piezoelectric element is discharged; (c) a step of setting the discharge characteristic of the piezoelectric element according to the piezoelectric element characteristic information; (d) A step of recording setting information indicating the set discharge characteristics in the nonvolatile memory. In the method the period may be used to determine whether the remaining amount of the stored consumable is more than a predetermined amount.

In the manufacturing method of the first aspect of the present invention, the piezoelectric element characteristic information is generated by measuring the characteristic of the piezoelectric element, and the discharge characteristic of the piezoelectric element is set based on the information, so that, for example, it is possible to simplify the setting of the discharge by manual adjustment. characteristic work. Accordingly, it is possible to reduce the burden of setting the required discharge characteristics of the piezoelectric element due to variations in the characteristics of the piezoelectric element. In addition, for example, it is possible to reduce the burden of measuring the characteristics of the piezoelectric element by performing the product inspection of the piezoelectric element at the same time.

In the above manufacturing method, the step (a) may also include the step of measuring the characteristics of the piezoelectric element and classifying it into a plurality of grades; the step (c) may also include setting the Steps for the discharge characteristics of piezoelectric elements. In this way, the present invention can be easily applied.

The manufacturing method according to the second aspect of the present invention is a method of manufacturing a consumable product container capable of measuring the remaining amount of the contained consumable product. The method includes: (a) the steps of preparing a consumables tank for storing the consumables; (b) mounting a piezoelectric element, a nonvolatile memory, and a circuit for charging and discharging the piezoelectric element in the (c) the step of setting the variable discharge characteristic of the piezoelectric element; (d) the step of judging whether the measurement can be performed; (e) the set discharge characteristic Record the steps in the non-volatile memory. In the method, said step (d) includes: (d-1) a step of charging said piezoelectric element; (d-2) a step of discharging said piezoelectric element; (d-3) generating a detection A signal step, wherein the detection signal includes information indicating a cycle of residual vibration after the piezoelectric element is discharged; (d-4) whether or not to measure the remaining amount of the stored consumables in response to the detection signal a step of judging; (d-5) according to the judgment that the measurement is impossible, setting a discharge characteristic different from the discharge characteristic judged to be impossible to measure, and returning the process to the step of the step (d) . In the method, it is characterized in that the period is operable to determine whether the remaining amount of the stored consumable is more than a predetermined amount.

In the manufacturing method according to the second aspect of the present invention, since a measurable setting state is automatically searched for by trial and error, the burden of setting the discharge characteristics can be reduced. Such a setting may be implemented as part of product inspection of the consumable container.

A consumables container according to a second aspect of the present invention is a consumables container capable of measuring the remaining amount of contained consumables. The consumable product container includes: a consumable product tank for accommodating the consumable product and having a piezoelectric element installed therein; a detection signal generation circuit for charging and discharging the piezoelectric element and generating a detection signal, the The detection signal includes information representing the period of the residual vibration after the piezoelectric element is discharged; the nonvolatile memory is used to store discharge characteristic setting information, and the discharge characteristic setting information is used to represent the piezoelectric element according to The piezoelectric element characteristic information of the characteristic sets the discharge characteristic of the piezoelectric element; and a control section for controlling charging and discharging of the piezoelectric element. In the consumables container, the cycle is used to determine whether the remaining amount of the stored consumables is more than a predetermined amount; the control unit may use the piezoelectric element characteristic information and the discharge characteristic setting information to set the discharge characteristic of the piezoelectric element.

The consumables container according to the second aspect of the present invention is configured so that the discharge characteristics of the piezoelectric element can be changed based on the information indicating the characteristics of the piezoelectric element. It is easy to set the discharge characteristics of the product container.

In the consumables container described above, the piezoelectric element characteristic information may be a grade selected from a plurality of grades based on measurement of the characteristics of the piezoelectric element; to set the discharge characteristics of the piezoelectric element.

In addition, the present invention can be realized in various ways, for example, can be realized in the form of a remaining amount measuring device, a remaining amount measuring method, and a remaining amount measuring control device, a computer program for realizing the functions of these methods or devices, A recording medium storing the computer program, a data signal embodied in a carrier wave including the computer program, a printing head and an ink cartridge used in the printing device, combinations thereof, and the like.

Description of drawings

FIG. 1 is a perspective view of the appearance of an ink cartridge 100 in an embodiment of the present invention;

FIG. 2 is a sectional view showing a section of a sensor SS mounted on a side portion of the cartridge body 140 of the ink cartridge 100;

FIG. 3 is a block diagram of a logic circuit 130 installed in the ink cartridge 100;

FIG. 4 is a circuit diagram showing the circuit structure of the ink remaining amount detection circuit 230 and the sensor SS;

FIG. 5 is a block diagram of a pulse counter 235 installed in the ink remaining amount detection circuit 230;

FIG. 6 is a flow chart of ink remaining amount measurement processing in an embodiment of the present invention;

FIG. 7 is a timing chart showing the operation of the remaining ink amount detection circuit 230 and the sensor SS;

8 is an explanatory diagram showing the applied voltage (potential difference from ground potential) of the piezoelectric element PZT;

FIG. 9 is an explanatory diagram showing a frequency response function (transfer function) of a sensor vibration system including a sensor SS;

FIG. 10 is an explanatory diagram showing a state in which a voltage is generated on the piezoelectric element PZT in response to discharge from the piezoelectric element PZT;

FIG. 11 is an explanatory diagram showing a state in which a voltage is generated on the piezoelectric element PZT in response to discharge from the piezoelectric element PZT;

12 is an explanatory diagram showing the contents of discharge characteristic setting processing in the embodiment of the present invention;

FIG. 13 is a flow chart showing a method of discharge characteristic setting processing in an embodiment of the present invention;

14 is an explanatory diagram showing the relationship between the sensor level and the setting state of the resistance circuit for adjusting the discharge time constant;

FIG. 15 shows discharge characteristic voltage waveforms from the piezoelectric element PZT in the modified example.

Detailed ways

Hereinafter, based on examples, embodiments of the present invention will be described in the following order.

A. The structure of the ink cartridge in the embodiment of the present invention:

B. The electrical structure of the ink cartridge in the embodiment of the present invention:

C. The circuit structure of the ink residual amount detection part in the embodiment of the present invention:

D. Ink remaining amount measurement processing in the embodiment of the present invention:

E. Contents of the discharge characteristic setting process in the embodiment of the present invention:

F. The method of the discharge characteristic measurement processing in the embodiment of the present invention:

G. Variations:

A. The structure of the ink cartridge:

FIG. 1 is an external perspective view of an ink cartridge 100 in an embodiment of the present invention. The ink cartridge 100 includes a cartridge body 140 in which an ink as a consumable is stored. An ink supply port 110 is provided at the lower part of the box body 140 for supplying ink to a printer described later. An antenna 120 and a logic circuit 130 are installed on the upper part of the box body 140 for communicating with the printer through radio waves. On a side portion of the cartridge body 140, a sensor SS for measurement of the remaining amount of ink is installed. The sensor SS is electrically connected to the logic circuit 130 .

FIG. 2 is a cross-sectional view showing a cross-section of the sensor SS attached to the side portion of the cartridge body 140 of the ink cartridge 100 . The sensor SS includes: a piezoelectric element PZT having piezoelectric element characteristics called piezoelectric effect and inverse piezoelectric effect; two electrodes 10 , 11 applying a voltage to the piezoelectric element PZT; and a sensor attachment 12 . The electrodes 10 , 11 are connected to a logic circuit 130 . The sensor attachment 12 is a constituent part of the sensor SS having a thin film that conducts vibration from the piezoelectric element PZT to the ink and cartridge 140 .

FIG. 2( a ) shows a case where more than a predetermined amount of ink remains and the liquid level of the ink is higher than the position of the sensor SS ( FIG. 1 ). FIG. 2( b ) shows a case where the liquid level of the ink is lower than the position of the sensor SS because no more than a predetermined amount of ink remains.

As can be seen from these drawings, when the liquid level of the ink is higher than the position of the sensor SS, the sensor SS, the ink and the box body 140 constitute a vibrating body, and when the liquid level of the ink is lower than the position of the sensor SS, the sensor SS, the box body 140 140 and only a small amount of ink attached to the sensor SS constitutes a vibrating body. As a result, the vibration characteristics around the piezoelectric element PZT change according to the remaining amount of ink. In this embodiment, the measurement of the ink remaining amount is performed using such a change in the vibration characteristic. In addition, the details of the measurement method will be described later.

B. The electrical structure of the cartridge:

FIG. 3 is a block diagram of the logic circuit 130 installed in the ink cartridge 100 . The logic circuit 130 includes an RF circuit 200, a control section 210, an EEPROM 220 as a nonvolatile memory, an ink remaining amount detection circuit 230, a power generation section 240, and a charge pump circuit 250.

The RF circuit 200 includes a demodulation unit 201 for demodulating radio waves received from the printer 20 via the antenna 120 and a modulation unit 202 for modulating a signal received from the control unit 210 And sent to the printer 20. The printer 20 uses the antenna 121 to transmit the baseband signal to the ink cartridge 100 via a carrier wave of a predetermined frequency. On the other hand, the ink cartridge 100 may vary the impedance of the antenna 121 by varying the load of the antenna 120 without using a carrier. The ink cartridge 100 sends a signal to the printer 20 using this change in impedance. In this way, the ink cartridge 100 and the printer 20 can perform two-way communication.

The power generation unit 240 rectifies the carrier wave received by the RF circuit 200 to generate power at a predetermined voltage (for example, 5V). The power generation part 240 supplies power to the RF circuit 200, the control part 210, the EEPROM 220 and the charge pump circuit 250. The charge pump circuit 250 supplies power to the remaining ink amount detection circuit 230 after boosting the voltage to a predetermined voltage required by the sensor SS.

C. The circuit structure of the ink residual amount detection circuit 230 in the embodiment of the present invention:

FIG. 4 is a circuit diagram showing the circuit configuration of the remaining ink amount detection circuit 230 and the sensor SS. The remaining ink amount detection circuit 230 includes a PNP transistor Tr1 , an NPN transistor Tr2 , a resistor R1 for adjusting a charging time constant, a resistor circuit Rs for adjusting a discharging time constant, an amplifier 232 and a pulse counter 235 . The sensor SS is connected to an ink remaining amount detection circuit 230 through two electrodes 10, 11 (FIG. 2).

The discharge time constant adjusting resistor circuit Rs has four discharging time constant adjusting resistors R2a, R2b, R2c, R2d and four switches Sa, Sb, Sc, Sd respectively connected thereto. The four switches Sa, Sb, Sc, and Sd can be opened and closed by the control unit 210 . Through the combination of these switches, the control unit 210 can set the resistance value of the discharge time constant adjusting resistor circuit Rs.

The PNP transistor Tr1 is connected as follows. Its base is connected to a terminal TA which receives a control output from the control unit 210 . The emitter is connected to the charge pump circuit 250 via the resistor R1 for adjusting the charging time constant. The collector is connected to the electrode 10 which is one electrode of the sensor SS. The electrode 11 which is the other electrode of the sensor SS is grounded.

The NPN transistor Tr2 is connected as follows. The base is connected to a terminal TB which receives a control output from the control section 210 . The collector is connected to the electrode 10 which is one electrode of the sensor SS. The emitter is grounded via the resistance circuit Rs for adjusting the discharge time constant whose resistance value can be changed as described above.

The pulse sensor 235 is connected to the electrode 10 connected to the piezoelectric element PZT via an amplifier 232 that amplifies the voltage output from the piezoelectric element PZT. The pulse counter 235 is connected to the control unit 210 so as to receive a control output from the control unit 210 .

FIG. 5 is a block diagram of the pulse counter 235 incorporated in the ink remaining amount detection circuit 230 . The pulse counter 235 includes: a comparator 234 , a counter control unit 236 , a counting unit 238 , and an oscillator not shown in the figure. The output of the amplifier 232 to be analyzed and the reference potential Vref to be compared are input to the comparator 234 . The counter control unit 236 and the counting unit 238 are connected to the control unit 210 . In addition, the remaining ink amount detection circuit 230 corresponds to a "detection signal generation circuit" in the claims.

D. Ink remaining quantity measurement process in the embodiment of the present invention:

FIG. 6 is a flowchart of a method of ink remaining amount measurement processing in the embodiment of the present invention. FIG. 7 is a timing chart showing the operations of the remaining ink amount detection circuit 230 and the sensor SS. This processing is executed by both the ink cartridge 100 and the printer 200 in response to the operation of the power switch of the printer 20 , for example. In the ink cartridge 100 , the number of clock signals is counted during a predetermined number (for example, 5) of voltage waves output from the piezoelectric element PZT are generated. On the other hand, the printer 20 calculates the frequency of the voltage wave from the counted value, and estimates the state of the remaining amount of ink from the calculated frequency. Specifically, the following processing is performed.

In step S100 , the control unit 210 ( FIG. 4 ) sets the discharge time constant of the piezoelectric element PZT by opening and closing four switches Sa, Sb, Sc, and Sd through the discharge time constant adjusting resistor circuit Rs. The details of the setting process of the discharge time constant will be described later.

In step S110 , the control unit 210 ( FIG. 4 ) outputs a predetermined control output signal to the terminal TA at time t0 to turn on the transistor Tr1 . Accordingly, a current flows from the charge pump circuit 250 into the piezoelectric element PZT, and a voltage is applied to the piezoelectric element PZT having capacitance by the current. Furthermore, in the initial state, both transistors Tr1, Tr2 are turned off.

The control unit 210 turns off the transistor Tr1 at time t1, and makes the remaining ink amount detection circuit 230 stand by until time t2. The standby until time t2 is to attenuate the vibration of the piezoelectric element PZT due to the voltage application. In addition, timekeeping is performed by a clock not shown inside the control unit 210 .

In step S120, control unit 210 (FIG. 4) sends a predetermined control output signal to terminal TB at time t2 so that transistor Tr2 is turned on at time t2 and turned off at time t3. Thus, the discharge from the piezoelectric element PZT is performed only from time t2 to time t3. The piezoelectric element PZT is rapidly deformed by this discharge, thereby exciting the sensor vibration system to vibrate. The sensor vibration system is a system including the sensor SS ( FIG. 2 ) and a cartridge around the sensor SS and ink in this embodiment.

FIG. 8 is an explanatory diagram showing a discharge waveform of the piezoelectric element PZT during discharge. FIG. 8( a ) is an explanatory diagram showing a discharge waveform in a time domain. The voltage at each moment is as follows:

(1) Discharge start time t2: potential Vch (output potential of charge pump circuit 250);

(2) Time constant moment td: potential decreased by 63.2% from the potential Vch;

(3) Discharge end time t3: Potential slightly higher than ground potential (FIG. 8).

Here, the time constant time td is a time constant elapsed from the discharge start time t2. In addition, in this specification, the time from the discharge start time t2 to the discharge end time t3 during which the piezoelectric element PZT and the ground are in a conduction relationship is referred to as a discharge time.

FIG. 8( b ) is an explanatory diagram showing a fundamental wave and a plurality of high-frequency waves of an applied voltage in a frequency range. This is a schematic diagram of the results of Fourier analysis assuming that the waveform of the applied voltage to the piezoelectric element PZT in the first window ( FIG. 7 ) repeats forever. As a result, it can be seen that the applied voltage becomes a voltage wave composed of a fundamental frequency which is the reciprocal of the discharge time and a high-frequency wave having a frequency which is an integer multiple thereof. Here, assuming that the distortion of the piezoelectric element PZT has a linear relationship with the applied voltage for easy understanding of the description, the waveform of the excitation force coincides with the waveform of the applied voltage.

FIG. 9 shows a frequency response function (transfer function) of the sensor vibration system including the sensor SS. The so-called frequency response function is a function that expresses the relationship between the input and output of the vibration transmission system of the sensor vibration system, and is represented by the ratio of the input Fourier spectrum to the output Fourier spectrum. That is, the frequency response function of this embodiment is the ratio of the Fourier spectrum of the discharge waveform (linear relationship with the exciting force) of the piezoelectric element PZT to the Fourier spectrum of the free vibration of the sensor vibration system.

The first mode and the second mode in FIG. 9 represent two natural modes of the sensor vibration system. The eigenmode is the shape formed by the vibration of the sensor vibration system. In other words, all objects have their own inherent shape when they vibrate, so they cannot vibrate in other shapes. This intrinsic shape is the intrinsic mode. The intrinsic mode of an object can be obtained by model analysis.

Assume that the ink cartridge 100 has the following two vibration modes.

(1) In the first mode, the sensor SS ( FIG. 2 ) deforms into a bowl-shaped vibration mode in which the edge portion of the concave portion of the sensor SS ( FIG. 2 ) becomes a node of vibration and the center of the concave portion becomes an amplitude of vibration.

(2) In the second mode, both the edge portion and the center portion of the concave portion of the sensor SS are nodes of vibration, and the middle portion between the edge portion and the center portion becomes the amplitude of vibration at two places on the left and right when viewed from the center, Thereby deforming into a swing-shaped vibration mode.

In this way, the sensor vibration system only generates free vibrations caused by excitation at the natural vibration frequencies of the first mode and the second mode. On the other hand, even if the piezoelectric element PZT excites the sensor vibration system to vibrate at other frequencies, the free vibration generated in the sensor vibration system will immediately attenuate to a minimum.

FIG. 10 is an explanatory view showing a state in which a voltage is generated on the piezoelectric element PZT in response to free vibration from the piezoelectric element PZT. FIG. 10( a ) superimposes the waveform ( FIG. 8( b )) of the applied voltage (during discharge) in the frequency region on the frequency response function of the sensor vibration system ( FIG. 9 ), and shows them with solid and dotted lines, respectively. FIG. 10(b) shows the output voltage of the piezoelectric element PZT.

It can be seen from Fig. 10(a) that the frequency of the fundamental wave of the discharge waveform is adjusted so that it is roughly consistent with the natural vibration frequency of the first mode of the sensor vibration system, and the discharge waveform is consistent with the frequency of the second mode of the sensor vibration system High frequency waves do not exist. As a result, large free vibrations are produced only at the natural frequency of the first mode of the sensor vibration system. As a result, a large voltage is generated on the piezoelectric element PZT only at the natural vibration frequency of the first mode of the sensor vibration system ( FIG. 10( b )). This agrees with the Fourier analysis result of the waveform in the second window ( FIG. 7 ) assuming that the waveform of the output voltage of the piezoelectric element PZT repeats forever.

In the present embodiment, the liquid level of the ink is measured by using a slight change in the natural vibration frequency of the first mode of the sensor vibration system. That is, in this embodiment, the natural frequency of the first mode slightly changes depending on whether the liquid level of the ink is higher than the sensor SS. Based on this change, the positional relationship between the sensor SS and the liquid level of the ink is determined. Therefore, it can be seen that, as a result, radio waves of other frequencies become noise.

In step S130 ( FIG. 6 ), the control unit 210 makes the remaining ink amount detection circuit 230 wait again between time t3 and time t4 in FIG. 7 . This standby time is to attenuate unnecessary vibrations that become noise sources. During this standby time, vibrations at frequencies other than the natural vibration frequencies of the first mode and the second mode are basically eliminated. The standby time ends at time t4 as described above.

The control unit 210 ( FIG. 5 ) outputs a counter activation signal to the counter control unit 236 at time t4. The counter control unit 236 having received the counter activation signal outputs the count activation signal to the count unit 238 . The output of the count activation signal starts in response to the first rising edge Edge1 of the comparator output after receiving the signal (time t5 ), and ends in response to the sixth rising edge Edge6 (time t6 ). In addition, in the comparator 234, the reference potential Vref which is a comparison object is set to the ground potential in this embodiment.

In step S140, the counting unit 238 counts the clock. Counting by the clock is performed only while the counting unit 238 receives the count activation signal. Thus, the number of clock signals between the rising edge Edge1 and the sixth rising edge Edge6 output from the comparator is counted. That is, the clock signal of 5 periods of the voltage wave output from the piezoelectric element PZT is counted.

In step S150, the counting unit 238 outputs a count value. The output count value is sent to the printer 20 . The printer 20 calculates the frequency of the voltage wave output by the piezoelectric element PZT according to the received count value and clock cycle.

In step S160, the printer 20 may determine whether the remaining amount of ink is above a predetermined amount according to the frequency. For example, it is assumed that when the liquid level of the ink is higher than the position of the sensor SS, the frequency is approximately 90 kHz, and when the liquid level of the ink is lower than the position of the sensor SS, the frequency is approximately 110 kHz. At this time, if the calculated frequency is, for example, 105 kHz, it can be known that the ink remaining amount is less than a predetermined value (steps S170, S180).

E. Contents of the discharge characteristic setting process in the embodiment of the present invention:

FIG. 11 is an explanatory diagram showing a state in which a voltage is generated in the piezoelectric element PZT in response to free vibration from the piezoelectric element PZT, as in FIG. 10 . Here, it is the state of the generated voltage in the state before the discharge characteristic is set appropriately. Since it is before adjustment, the frequency of the fundamental wave of the applied voltage at the time of discharge coincides with the natural vibration frequency of the first mode of the sensor vibration system, and on the other hand, it coincides with the natural vibration frequency of the second mode of the sensor vibration system High-frequency wave of the applied voltage at the time of discharge.

As a result, a large voltage is generated not only at the natural frequency of the first mode but also at the natural frequency of the second mode. Therefore, it can be seen that the voltage wave at the natural frequency of the second mode becomes noise and interferes with the measurement of the remaining amount of ink.

Fig. 12 is an explanatory view showing the state of discharge characteristic setting processing in the embodiment of the present invention. FIG. 12( a ) shows the discharge waveform after the discharge characteristic is set, and is the same graph as FIG. 8( a ). Fig. 12(b) shows the discharge waveform before setting the discharge characteristics.

In this example, a discharge time constant and a discharge time are set as discharge characteristics. The discharge time constant is the product of the resistance value between the piezoelectric element PZT and the ground and the capacitance of the piezoelectric element PZT. The discharge time constant can be set by adjusting the resistance value of the resistance circuit Rs for discharge time constant adjustment. This resistance value can be set by opening and closing each discharge time constant adjustment resistance control switch Sa, Sb, Sc, Sd in an appropriate combination.

On the other hand, the discharge time is the time during which the piezoelectric element PZT and the ground are in a conduction state as described above. Specifically, it is the time when the control unit 210 turns on the transistor Tr2. The discharge time can be freely set by the control unit 210 .

In this way, if the discharge time constant is changed from time constant Td' to time constant Td, and the discharge end time is extended from t3' to t3, thereby changing the discharge time, the discharge waveform shown in Figure 12(a) are the same waveform.

In this way, according to the ink cartridge 100 of the embodiment of the present invention, the discharge characteristics from the piezoelectric element PZT can be changed, and therefore, the characteristics of the residual vibration after discharge can be changed to the characteristics of high S/N which are preferable in remaining amount detection. As a result, the reliability of the measurement can be improved.

F. The method of discharge characteristic setting processing in the embodiment of the present invention:

FIG. 13 is a flowchart showing a method of discharge characteristic setting processing in the embodiment of the present invention. The discharge characteristic setting process can be performed at the time of manufacture and when the user uses the ink cartridge 100 . The processing in steps S200 and S210 is setting processing at the time of manufacture, and the processing after step S220 is setting processing when the user uses the ink cartridge 100 . In addition, in this example, only the discharge time constant is set for ease of explanation.

In step S200, the manufacturer of the sensor SS determines the sensor grade of the sensor SS. The sensor class SS is a class indicating the relationship between the applied voltage and distortion and other sensor characteristics. The determination of the sensor class is carried out by actually measuring the characteristics of the sensor. In this embodiment, the sensors SS are classified into 8 stages from A to H. In addition, the sensor level corresponds to "piezoelectric element characteristic information" in the claims.

In step S210, the manufacturer of the ink cartridge 100 performs initial setting of the discharge characteristic according to the determined sensor level. The initial setting of the discharge characteristic is performed based on the relationship between the predetermined sensor level and the setting state of the discharge time constant adjusting resistance circuit Rs ( FIG. 14 ). In addition, the sensor level and the setting state of the resistor circuit Rs for adjusting the discharge time constant correspond to "discharge characteristic setting information" in the claims.

For example, when the sensor class is B, three switches Sa, Sb, Sc among the four switches Sa, Sb, Sc, and Sd of the resistance circuit Rs for adjusting the discharge time constant are set to "ON", and the switches Sd is set to "OFF". Here, the resistance values of resistors Ra, Rb, Rc, and Rd, which are controlled by the opening and closing of switches Sa, Sb, Sc, and Sd, are 100Ω, 200Ω, 400Ω, and 800Ω (FIG. 14).

The setting content is stored together with the sensor level in the non-volatile memory that the ink cartridge 100 is equipped with in the logic circuit 130, that is, in the EEPROM 220. In addition, information indicating that the remaining amount of ink is equal to or greater than a predetermined amount is also stored when ink is injected. Thus, the information indicating the discharge characteristics set at the last measurement is stored in the nonvolatile memory, and since the measurement is performed with the stored settings, the reliability of the measurement can be easily improved. advantage.

In step S220, the user performs a measurement test of the remaining amount of ink. The measurement test is performed automatically once the ink cartridge 100 is installed in the printer 20 . The printer 20 is implemented by the procedure shown below.

(1) According to the information indicating the remaining amount stored in the EEPROM 220, it is confirmed that the remaining amount of ink is more than a predetermined amount.

(2) Based on the information stored in the EEPROM 220, the resistance circuit Rs for adjusting the discharge time constant is set.

(3) The processing from step S110 to step S160 in the method ( FIG. 6 ) of executing the ink remaining amount measurement processing.

In step S230, the printer 20 determines whether the measured value is within a predetermined allowable range. In this example, the predetermined allowable range is set to a frequency when the remaining amount of ink is equal to or greater than a predetermined amount, that is, 90 kHz±5 kHz. As a result of this determination, when the measured value is within the predetermined allowable range, the discharge characteristic setting process ends. On the other hand, when the measured value is not within the predetermined allowable range, the process proceeds to step S240. In addition, the judgment of whether it is within the allowable range corresponds to "judgment of whether the remaining amount of consumables can be measured" in the claims.

In step S240, the printer 20 repeats the measurement after resetting the discharge time constant adjusting resistance circuit Rs in a predetermined order. For example, when the sensor level stored in the EEPROM 220 is C, set it to B and measure it, set it to D and measure it, set it to A and measure it, set it to E and measure it and measure it repeatedly until into the allowable range. Thereby, there is an advantage that the discharge characteristic that can measure the remaining amount of ink is automatically set, and the discharge-specific setting can be made reliable and appropriate.

In addition, the processing from step S220 to step S240 may be performed on the manufacturer's side. In addition, the processing from step S200 to step S210 can be omitted both when the manufacturer makes the setting and when the user makes the setting.

G. Variations:

In addition, this invention is not limited to the said Example or embodiment, It can implement in various states in the range which does not deviate from the summary, For example, it can deform|transform as follows.

G-1. In each of the above-mentioned embodiments, the piezoelectric element PZT was used as a sensor element, but Rochelle salt (potassium sodium tartrate), for example, may also be used. The sensor used in the present invention may use a piezoelectric element having two characteristics of an inverse piezoelectric effect that deforms according to charging and discharging, and a piezoelectric effect that generates a voltage due to deformation.

G-2. In the above embodiment, the discharge characteristic is changed by adjusting the conduction time of the transistor Tr2 and the time constant determined by the piezoelectric element and the discharge time constant adjusting resistor, but only one of them may be adjusted. In addition, for example, it is also possible to change the discharge characteristics by adding a constant current circuit to the discharge circuit to form the discharge waveform shown in FIG. 15 .

G-3. In the above-mentioned embodiments, the discharge time constant is adjusted by changing the resistance value of the resistance circuit for adjusting the discharge time constant, but it is also possible to adjust the time constant by connecting capacitors in parallel to the piezoelectric element and changing the capacitance, for example .

G-4. In the above-described embodiments, the measurement object of the remaining amount is ink, but it may be, for example, toner. The measurement object of the remaining amount in the present invention may be consumables that have decreased due to use of the equipment.

G-5. In the method of the discharge characteristic setting process of the above-mentioned embodiment, the discharge of the piezoelectric element is set using a table representing the relationship between the predetermined sensor level and the setting state of the discharge time constant adjustment resistor circuit Rs. However, for example, the characteristics of the piezoelectric element are measured as characteristic values representing the relationship between voltage and distortion, and based on the measurement results, the discharge characteristics are set according to an algorithm stored in a nonvolatile memory or a computer. Can.

The algorithm may also be configured as follows: For example, by using a predetermined calculation formula, the optimal value of discharge characteristics such as time constant and discharge time is calculated from the above-mentioned characteristic values, and the setting state closest to the optimal value is selected. The discharge characteristic setting process performed in the present invention can generally be configured to set the discharge characteristic of the piezoelectric element based on piezoelectric element characteristic information indicating the piezoelectric element characteristic. In addition, in this case, the algorithm corresponds to "discharge characteristic setting information" in the claims.

When some or all of the functions of the present invention are realized by software, the software (computer program) may be provided in a form stored in a computer-readable recording medium. In the present invention, the so-called "computer-readable recording medium" is not limited to portable recording media such as floppy disks and CD-ROMs, but also includes internal storage devices such as various RAMs and ROMs in computers, and hard disks, etc. inherent to computers. external storage device.

Industrial Applicability

The present invention is applicable to a consumable container used in an output device of a computer.

Claims (13)

1. consumable container can be measured the residual volume of the consumables that held, and it is characterized in that, comprising:

The consumables jar is used to hold described consumables, and piezoelectric element is installed;

The detection signal generative circuit is used to carry out the charging and the discharge of described piezoelectric element, and generates detection signal, and described detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

Control part is used for the charging and the discharge of described piezoelectric element are controlled,

It is characterized in that,

The described cycle can be used for determining whether the residual volume of consumables of described storage is more than scheduled volume;

Described control part can change the flash-over characteristic of described piezoelectric element.

2. consumable container as claimed in claim 1, wherein,

Described control part can change the discharge time constant of described piezoelectric element.

3. consumable container as claimed in claim 1 or 2, wherein,

Described control part can change the discharge time of described piezoelectric element.

4. as each described consumable container in the claim 1 to 3, wherein,

Described detection signal generative circuit comprises:

Voltage generating circuit is used for producing predetermined potential difference (PD) between second terminal of the first terminal of hot side and low potential side;

Piezoelectric element, one end are connected on described second terminal;

Charging control switch is connected between the other end of described the first terminal and described piezoelectric element, is used for according to the control output from described control part, to carrying out switch control from described the first terminal to the charging of described piezoelectric element;

Discharge control switch is connected between the other end and described second terminal of described piezoelectric element, is used for according to the control output from described control part, to carrying out switch control from described piezoelectric element to the discharge of described second terminal;

Resistance circuit is to be connected the other end of described piezoelectric element and the circuit between described second terminal, and it can change resistance value;

Wherein, described control part carries out the control of the resistance value of the switch control of the switch control of described charging control switch, described discharge control switch and described resistance circuit.

5. measuring method is used to measure the residual volume of the consumables in the consumable container, it is characterized in that, comprising:

(a) prepare to be used to the consumables jar that holds described consumables and piezoelectric element is installed and be used to carry out the step of the circuit that discharges and recharges of described piezoelectric element;

(b) step of the flash-over characteristic of the described piezoelectric element of variable setting;

(c) carry out the step of described measurement;

Wherein, described step (c) comprising:

(c-1) step of charging for described piezoelectric element;

(c-2) from the step of described piezoelectric element discharges;

(c-3) step of generation detection signal, wherein said detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

(c-4), determine the step whether residual volume of the consumables of described storage Duos than scheduled volume in response to described detection signal.

6. measuring method as claimed in claim 5, wherein,

Described step (c) also comprises: in response to described detection signal, the residual volume of the consumables that could measure described storage is judged, and processing is turned back to the step of described step (b) according to the judgement that can not carry out described measurement;

Described step (b) comprising: according to the judgement that can not carry out described measurement, described flash-over characteristic is set at and is judged as the different flash-over characteristic of flash-over characteristic that can not carry out described measurement, and processing is advanced to the step of described step (c).

7. measuring method as claimed in claim 6 also comprises:

(d) step of preparation nonvolatile memory; With

(e) set information is recorded in step in the described storer, the setting content of the flash-over characteristic that wherein said set information sets when representing described the measurement;

Wherein, described step (b) comprises the step of setting flash-over characteristic according to the described set information of reading from described nonvolatile memory.

8. computer program, described computer program makes the computer control consumable container, so that the flash-over characteristic of the piezoelectric element that consumable container had of the residual volume that can measure institute's holding consumables is set, wherein,

Described consumable container comprises:

The consumables jar is used to hold described consumables, and piezoelectric element is installed;

The detection signal generative circuit is used to carry out the charging and the discharge of described piezoelectric element, and generates detection signal, and described detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

Control part is used for the charging and the discharge of described piezoelectric element are controlled, and can changes the flash-over characteristic of described piezoelectric element; With

Nonvolatile memory is used for the residual volume the information whether residual volume of the set information of setting content of the described flash-over characteristic of storage representation and the described consumables of expression Duos than scheduled volume;

Described computer program comprises the program that makes described computer realization following function:

(a) read the function of described set information and described residual volume information from described nonvolatile memory;

(b) set the function of the flash-over characteristic of described piezoelectric element based on described set information;

(c), confirm the function that the residual volume of described consumables is Duoed than described scheduled volume based on described residual volume information;

(d) generate the function of detection signal according to described affirmation, wherein said detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

(e) receive described detection signal, and the function of the residual volume that whether can measure described consumables being judged in response to the detection signal of described reception;

(f), when being judged as to carry out described measurement the time, being set at and being judged as the different flash-over characteristic of flash-over characteristic that to carry out described measurement, and processing is turned back to the function of described function (d) in response to the judgement that could carry out described measurement;

(g),, make the set information of setting content of the flash-over characteristic of the described setting of expression be recorded in function in the described nonvolatile memory when being judged as to carry out described measurement the time in response to the judgement that could carry out described measurement.

9. a manufacture method is a method of making the consumable container of the residual volume that can measure the consumables that held, it is characterized in that, comprising:

(a) measure the characteristic of piezoelectric element, and generate the step of the piezoelectric element characteristic information of the characteristic of representing described piezoelectric element;

(b) prepare to be used to store the step of the consumables jar of described consumables;

(c) described piezoelectric element, detection signal generative circuit and nonvolatile memory are installed in step on the described consumables jar, wherein said detection signal generative circuit carries out the charging and the discharge of described piezoelectric element, and the generation detection signal, described detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

(c) set the step of the flash-over characteristic of described piezoelectric element according to described piezoelectric element characteristic information;

(d) set information that will represent the flash-over characteristic of described setting is recorded in the step in the described nonvolatile memory;

Wherein, the described cycle can be used for determining whether the residual volume of consumables of described storage is more than scheduled volume.

10. the manufacture method of consumable container as claimed in claim 9, wherein,

Described step (a) comprises the characteristic of measuring piezoelectric element and the step that is categorized as a plurality of grades;

Described step (c) comprises the step according to the flash-over characteristic of the described piezoelectric element of level setting of described classification.

11. the manufacture method of a consumable container is a method of making the consumable container of the residual volume that can measure the consumables that held, it is characterized in that, comprising:

(a) prepare to be used to store the step of the consumables jar of described consumables;

(b) piezoelectric element, nonvolatile memory and the circuit that discharges and recharges that carries out described piezoelectric element are installed in step on the described consumables jar;

(c) step of the variable flash-over characteristic of the described piezoelectric element of setting;

(d) judge the step that described measurement could be carried out;

(e) flash-over characteristic of described setting is recorded in step in the described nonvolatile memory;

Wherein, described step (d) comprising:

(d-1) step of charging for described piezoelectric element;

(d-2) from the step of described piezoelectric element discharges;

(d-3) step of generation detection signal, wherein said detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

(d-4), carry out to measure the step of judgement of residual volume of the consumables of described storage in response to described detection signal;

(d-5), be set at and be judged as the different flash-over characteristic of flash-over characteristic that to measure, and processing is turned back to the step of described step (d) according to carrying out the judgement of described measurement;

Wherein, the described cycle can be used for determining whether the residual volume of described stored consumables is more than scheduled volume.

12. a consumable container can be measured the residual volume of the consumables that held, and it is characterized in that, comprising:

The consumables jar is used to hold described consumables, and piezoelectric element is installed;

The detection signal generative circuit is used to carry out the charging and the discharge of described piezoelectric element, and generates detection signal, and described detection signal comprises the information in the cycle of the residual vibration after the described piezoelectric element discharges of expression;

Nonvolatile memory is used to store the flash-over characteristic set information, and described flash-over characteristic set information is used for setting according to the piezoelectric element characteristic information of the characteristic of the described piezoelectric element of expression the flash-over characteristic of described piezoelectric element; With

Control part is used for the charging and the discharge of described piezoelectric element are controlled,

Wherein, the described cycle can be used for determining whether the residual volume of consumables of described storage is more than scheduled volume;

Described control part can be set the flash-over characteristic of described piezoelectric element according to described piezoelectric element characteristic information and described flash-over characteristic set information.

13. consumable container as claimed in claim 12, wherein,

Described piezoelectric element characteristic information is a selected grade according to the measurement of the characteristic of described piezoelectric element and from a plurality of grades;

Described control part is set the flash-over characteristic of described piezoelectric element according to the grade of described selection.

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