JP4576958B2 - Printing apparatus and method for detecting state of printing material - Google Patents

Description

  The present invention relates to a printing apparatus, and more particularly to a technique for detecting a state of a printing material accommodated in a printing material container mounted on the printing apparatus.

  A printing apparatus (for example, an ink jet printer) that performs printing by mounting a printing material container (for example, an ink cartridge) that stores printing material, detects the state of the stored printing material and performs appropriate management. There is a request to do it. For example, the amount of ink remaining in the container is measured to manage the amount of ink in the cartridge.

As one of such techniques for detecting the remaining amount of ink, one using a piezoelectric element as a sensor for measuring the amount of ink is known. In this technique, a piezoelectric element is exposed to a space (cavity) in which ink is stored in a cartridge, and a pulse voltage is applied to the piezoelectric element to vibrate the piezoelectric element. The vibration of the piezoelectric element generated as a result resonates the vibration element composed of the piezoelectric element and its peripheral region. By measuring the frequency of the voltage output from the piezoelectric element by this resonance vibration, the natural frequency of the vibrating body composed of the piezoelectric element and its peripheral region is obtained. Then, the ink amount is detected from the obtained difference in natural frequency (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2004-136539

  However, conventionally, since the waveform and number of times of the pulse voltage to be applied are not taken into consideration, the vibration of the piezoelectric element generated as a result cannot sufficiently resonate the vibrating body composed of the piezoelectric element and its peripheral region, In some cases, the voltage output from the piezoelectric element is reduced by resonance vibration. As a result, the voltage frequency cannot be measured correctly, and there is a possibility that the remaining amount of ink cannot be detected accurately. Such a problem is not limited to the detection of the remaining amount of ink in the ink cartridge, but is a common problem in the technology of detecting the state of the printing material using a piezoelectric element as a sensor.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the detection accuracy of a printing apparatus that detects the state of a printing material using a piezoelectric element as a sensor.

  In order to solve at least a part of the above problems, the present invention provides a printing apparatus. The printing apparatus according to the first aspect of the present invention includes a piezoelectric element disposed in the printing material container and a frequency component corresponding to a natural frequency of the piezoelectric element when the printing material is in a predetermined state. Voltage generating means for generating a piezoelectric element driving voltage having a waveform including many; voltage applying means for applying the generated piezoelectric element driving voltage to the piezoelectric element to vibrate the piezoelectric element; and After the application, the frequency measuring means for measuring the frequency of the voltage output from the vibrating piezoelectric element by the piezoelectric effect, and the printing material based on the natural frequency of the piezoelectric element detected as the frequency of the voltage And a state determining means for determining the state.

  According to the printing apparatus according to the aspect of the present invention, since a voltage having a waveform including many frequency components corresponding to the natural frequency of the piezoelectric element when the printing material is in a predetermined state is applied to the piezoelectric element, printing is performed. When the material is in a state corresponding to a predetermined frequency, the piezoelectric element can be sufficiently vibrated at a predetermined natural frequency by a resonance phenomenon. As a result, in the voltage output from the piezoelectric element due to the piezoelectric effect, the frequency component corresponding to the predetermined natural frequency increases. Therefore, when the frequency of the output voltage is measured to detect the natural frequency of the piezoelectric element, if the printing material is in a state corresponding to the predetermined natural frequency, the predetermined natural frequency is surely determined. Can be detected. Then, it can be accurately determined that the printing material is in a state corresponding to a predetermined natural frequency.

  In the printing apparatus according to the first aspect of the present invention, the waveform of the piezoelectric element driving voltage may be a waveform that causes the piezoelectric element to repeat discharge a plurality of times at the same period as the period of vibration at the natural frequency. The waveform may be such that the piezoelectric element is repeatedly charged and discharged a plurality of times with the same period as the vibration period at the natural frequency. The waveform of the piezoelectric element driving voltage may be a waveform having the same period as the vibration period at the natural frequency and repeating a voltage drop a plurality of times. The waveform may be the same period as the vibration period at the natural frequency. The waveform may be such that the voltage rise and the voltage drop are repeated a plurality of times. In this way, when the printing material is in a state corresponding to a predetermined natural frequency by distorting the piezoelectric element at the same cycle as the predetermined frequency, the piezoelectric element is caused to have a predetermined natural frequency by a resonance phenomenon. It can be vibrated sufficiently.

  In the printing apparatus according to the first aspect of the present invention, the natural frequency is a first natural frequency when the printing material in the storage chamber is greater than or equal to a predetermined amount, and the state determination means is the detection unit. If the vibration frequency of the piezoelectric element is the first natural frequency, the printing material in the storage chamber may be determined to be greater than or equal to a predetermined amount. If it carries out like this, it can determine with a sufficient precision that the printing material of a storage chamber is more than predetermined amount.

  In the printing apparatus according to the first aspect of the present invention, the natural frequency is a second natural frequency when the printing material in the storage chamber is less than a predetermined amount, and the state determination unit is configured to detect the detection frequency. When the vibration frequency of the piezoelectric body is the second natural frequency, the printing material in the storage chamber may be determined to be less than a predetermined amount. In this way, it can be accurately determined that the printing material in the storage chamber is less than the predetermined amount.

  A second aspect of the present invention provides a printing apparatus. In the printing apparatus according to the second aspect of the present invention, the printing material container in which the printing material is accommodated, the piezoelectric element disposed in the printing material container, and the printing material in the accommodation chamber are in the first state. A frequency component corresponding to a first natural frequency of the piezoelectric element in a case and a frequency component corresponding to a second natural frequency of the piezoelectric element in a case where the printing material in the storage chamber is in a second state. Generating means for generating a piezoelectric element driving voltage having a waveform including many of the above, a voltage applying means for applying the generated piezoelectric element driving voltage to the piezoelectric element to vibrate the piezoelectric element, and driving the piezoelectric element After voltage application, based on the frequency measuring means for measuring the frequency of the voltage output from the vibrating piezoelectric element by the piezoelectric effect, and the natural frequency of the piezoelectric element detected as the frequency of the voltage Characterized in that it and a determining condition judging means a state of the printing material.

  In the printing apparatus according to the second aspect of the present invention, a voltage having a waveform including both a frequency component corresponding to the first natural frequency and a frequency component corresponding to the second natural frequency is applied to the piezoelectric element. Therefore, when the printing material is in the first or second state, the piezoelectric element can be sufficiently vibrated at the first or second natural frequency by the resonance phenomenon. As a result, in the voltage output from the piezoelectric element due to the piezoelectric effect, the frequency component corresponding to the first or second natural frequency increases. Therefore, when the frequency of the output voltage is measured and the natural frequency of the piezoelectric element is detected, if the printing material is in the first or second state, it is ensured that the first or second natural frequency The frequency can be detected. Then, it can be accurately determined that the printing material is in a state corresponding to the first or second frequency.

  In the printing apparatus according to the second aspect of the present invention, the waveform of the piezoelectric element driving voltage has a frequency component corresponding to the first natural frequency included in a unit waveform including a voltage increase and a voltage decrease. When the frequency component is smaller than the frequency component corresponding to the second natural frequency, the waveform of the piezoelectric element drive voltage is a waveform that repeats the unit waveform a plurality of times at the same cycle as the cycle of vibration at the first natural frequency. It may be. By doing so, the piezoelectric element is distorted at the same cycle as the first natural frequency, so that it is possible to increase the frequency component corresponding to the small first natural frequency. As a result, it is possible to obtain a waveform that includes both a frequency component corresponding to the first frequency and a frequency component corresponding to the second natural frequency.

  In the printing apparatus according to the second aspect of the present invention, the first state is a state where a predetermined amount or more of the printing material is present in the storage chamber, and the second state is a state where the printing material is present in the storage chamber. When the detected frequency of the piezoelectric element is the first natural frequency, the state determining means is in a state where there is less than a predetermined amount. If the detected frequency of the piezoelectric element is the second natural frequency, it may be determined that the printing material in the storage chamber is less than a predetermined amount. In this way, it can be accurately determined that the printing material in the storage chamber is a predetermined amount or more or that the printing material in the storage chamber is less than the predetermined amount.

  In the printing apparatus according to the above aspect, the voltage generation unit may be a voltage generation circuit capable of generating a voltage having an arbitrary waveform. In such a case, the piezoelectric element driving voltage described above can be easily generated.

  The printing apparatus according to the aspect further includes a print head that performs printing by applying a drive voltage, and an output destination of the voltage generated by the voltage generation unit, which is either the print head or the piezoelectric element. Switching means for switching between the two, and the voltage generating means may function as means for generating a head driving voltage applied to the print head. In this way, the means for generating the nozzle driving element driving voltage used for printing and the means for generating the piezoelectric element driving voltage used for detecting the state of the printing material can be realized by the same means.

  In the printing apparatus according to the above aspect, the printing material container may be a container that can be attached to and detached from the printing apparatus. If it carries out like this, the state of the printing material of the detachable printing material container can be determined accurately.

  According to a third aspect of the present invention, there is provided a method for detecting the state of a printing material accommodated in the printing material container using a piezoelectric element provided in the printing material container. The method according to the third aspect of the present invention generates a piezoelectric element driving voltage having a waveform including a lot of frequency components corresponding to the natural frequency of the piezoelectric element when the printing material is in a predetermined state, Applying the generated piezoelectric element driving voltage to the piezoelectric element to vibrate the piezoelectric element, and after applying the piezoelectric element driving voltage, measure the frequency of the voltage output from the vibrating piezoelectric element by the piezoelectric effect. The state of the printing material is determined based on the frequency of the piezoelectric element detected as the frequency of the voltage.

  According to the method of the third aspect of the present invention, it is possible to obtain the same operations and effects as those of the printing apparatus according to the first aspect of the present invention. In addition, the method according to the third aspect of the present invention can be realized in various aspects similarly to the printing apparatus according to the first aspect of the present invention.

  According to a fourth aspect of the present invention, there is provided a method for detecting a state of a printing material stored in the printing material container using a piezoelectric element provided in the printing material container. The method according to the fourth aspect of the present invention includes: a frequency component corresponding to a first natural frequency of the piezoelectric element when the printing material in the storage chamber is in a first state; and the printing material in the storage chamber. Generates a piezoelectric element driving voltage having a waveform including both frequency components corresponding to the second natural frequency of the piezoelectric element when the piezoelectric element is in the second state, and the generated piezoelectric element driving is generated in the piezoelectric element. The piezoelectric element is vibrated by applying a voltage, and after applying the piezoelectric element driving voltage, the frequency of the voltage output from the vibrating piezoelectric element by the piezoelectric effect is measured and detected as the frequency of the voltage The state of the printing material is determined based on the vibration frequency of the piezoelectric element.

  According to the method of the fourth aspect of the present invention, it is possible to obtain the same operations and effects as those of the printing apparatus according to the second aspect of the present invention. In addition, the method according to the fourth aspect of the present invention can be realized in various aspects similarly to the printing apparatus according to the second aspect of the present invention.

  Hereinafter, an image processing apparatus according to the present invention will be described based on examples with reference to the drawings.

A. Example:
・ Configuration of printing device and ink cartridge:
With reference to FIGS. 1 to 3, schematic configurations of a printing apparatus and an ink cartridge according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a printing apparatus as an embodiment of the present invention. FIG. 2 is a perspective view showing the print head unit and the ink cartridge according to this embodiment attached to the print head unit. FIG. 3 is a cross-sectional view showing a cross section of the sensor mounted on the casing of the ink cartridge.

  The printing apparatus 20 includes a sub-scan feed mechanism that transports the printing paper P in the sub-scan direction by the paper feed motor 22 and a main scan feed that reciprocates the carriage 30 in the axial direction (main scan direction) of the platen 26 by the carriage motor 24. A mechanism, a head drive mechanism that drives a print head unit 60 mounted on the carriage 30 to control ink ejection and dot formation, and these paper feed motor 22, carriage motor 24, print head unit 60, and operation panel 32 And a control circuit 40, which is a computer that manages the exchange of signals with. The control circuit 40 is connected to the computer 90 via the PC interface 80.

  The sub-scan feed mechanism that transports the printing paper P includes a gear train 23 that transmits the rotation of the paper feed motor 22 to the platen 26. Further, the main scanning feed mechanism for reciprocating the carriage 30 has an endless drive belt 36 between the carriage motor 24 and a slide shaft 34 that is installed in parallel with the axis of the platen 26 and slidably holds the carriage 30. And a position sensor 39 for detecting the origin position of the carriage 30.

  As shown in FIG. 2, the print head unit 60 includes a cartridge mounting portion 62 in which a plurality of (for example, six in this embodiment) ink cartridges C1 to C6 can be mounted, a print head 68, and ink cartridges C1 to C6. And a dedicated cartridge processing circuit 50 (not shown in FIG. 2), which is a dedicated circuit for executing processing related to the above.

  Although not shown, the print head 68 has a plurality of nozzles and piezo elements provided in each nozzle, and when a voltage is applied to the piezo elements, ink droplets are ejected from the nozzles to execute printing. To do.

  The cartridge mounting portion 62 includes ink introducing portions 66 and sensor terminal plates 100 corresponding to the number of ink cartridges that can be mounted. The ink introduction part 66 is inserted into the ink supply port 74 of the ink cartridges C1 to C6 described above when the ink cartridges C1 to C6 are attached to the cartridge attachment part 62, and introduces ink into the print head 68. On the terminal board 100, terminals 104 and 105 corresponding to the terminals arranged on the sensor terminal board 110 of the ink cartridge 70 are arranged.

  Next, the ink cartridges C1 to C6 will be described. As shown in FIG. 2, the ink cartridges C <b> 1 to C <b> 6 are containers that store one type of ink as a printing material. The ink cartridges C <b> 1 to C <b> 6 are used for a casing 71 in which an ink storage chamber RM that stores ink is formed, an ink supply port 74 for supplying ink to the printing apparatus 20, and detection of the remaining amount of ink. A sensor 72 and a terminal plate 110 corresponding to the terminal plate 100 of the cartridge mounting portion 62 described above are provided. The ink supply port 74 is installed at the lower part of the casing 71, and the sensor 72 is installed at the side of the casing 71. When the ink cartridges C1 to C6 are mounted on the cartridge mounting portion 62, the terminal plates 110 of the ink cartridges C1 to C6 are in contact with and electrically connected to the terminals 104 and 105 of the cartridge mounting portion 62 described above. Terminals 114 and 115 are arranged.

  As shown in FIG. 3, the sensor 72 includes a piezoelectric element PZT (for example, a piezo element) having a piezoelectric effect, two electrodes 720 and 721 that apply a voltage to the piezoelectric element PZT, and a sensor attachment 722. The electrodes 720 and 721 are connected to the terminals 114 and 115 described above, respectively. The sensor attachment 722 is a structural part of the sensor 72 having a thin film that transmits vibration from the piezoelectric element PZT to the ink storage chamber RM and the casing 71. With this configuration, the peripheral portion of the piezoelectric element PZT including at least a part of the ink storage chamber RM (hereinafter simply referred to as the peripheral portion) vibrates integrally with the piezoelectric element PZT.

FIG. 3A shows a state in which a predetermined amount or more of ink remains and the ink level is higher than the position of the sensor SS. FIG. 3B shows a state in which the ink remains less than a predetermined amount, and the ink level is lower than the position of the sensor 72. As shown in FIG. 3A, when the ink level is higher than the position of the sensor 72, that is, when the amount of ink in the ink storage chamber RM is equal to or larger than a predetermined amount, the peripheral portion of the piezoelectric element PZT has no ink Is filled. On the other hand, when the ink level is lower than the position of the sensor 72, that is, when the ink in the ink storage chamber RM is less than a predetermined amount, the area around the piezoelectric element PZT is not filled with ink. As a result, in the piezoelectric element PZT, the ink amount in the storage chamber RM is equal to or larger than the predetermined amount (hereinafter referred to as “when ink is present”), and the ink amount in the storage chamber RM is less than the predetermined amount (hereinafter referred to as “no ink”). Vibrates at different natural frequencies. In other words, the natural frequency of the piezoelectric element PZT here is not a value determined by one for each piezoelectric element PZT but a value determined by the influence of the peripheral portion of the piezoelectric element PZT. In the embodiment, the value varies depending on the presence or absence of ink. For example, in the ink cartridge of this embodiment, the natural frequency H ₁ when ink is present is 30 KHz, and the natural frequency H ₂ when ink is absent is 110 KHz. Such vibration characteristics change depending on various factors such as the shape, material, and ink material of the ink cartridge, and are not limited to the above values.

  The configuration of the control circuit 40 and the cartridge processing dedicated circuit 50 of the printer 20 will be described with reference to FIGS. FIG. 4 is an explanatory diagram showing the internal configuration of the control circuit 40. FIG. 5 is an explanatory diagram showing the internal configuration of the drive voltage generation circuit of the control circuit 40. FIG. 6 is an explanatory diagram showing the internal configuration of the cartridge processing dedicated circuit 50.

  The control circuit 40 includes a CPU 41, a PROM 42, a RAM 43, a transmitter 44 that generates a clock signal, peripheral devices that exchange signals with the paper feed motor 22, the carriage motor 24, the cartridge processing dedicated circuit 50, and the like. An input / output unit (PIO) 45, a drive voltage generation circuit 46 described later, and a drive buffer 47 are provided. The drive buffer 47 is used as a buffer for supplying dot on / off signals to the print head 68. These are connected to each other by a bus 49. A PC interface 80 for connecting an external computer 90 is connected to the bus 49. As a result, each of these components can exchange data with each other. The control circuit 40 is also provided with a distribution output device 48 that distributes the output voltage from the drive voltage generation circuit 46 to the print head 68 at a predetermined timing. The control circuit 40 outputs dot data to the drive buffer 47 at a predetermined timing while synchronizing with the movements of the paper feed motor 22 and the carriage motor 24.

  The drive voltage generation circuit 46 is provided in the ink cartridges C1 to C6 via the print head drive voltage COM1 applied to the piezoelectric element provided in the print head 68 via the distribution output device 48 and the cartridge processing dedicated circuit 50. And a sensor driving voltage COM2 applied to the piezoelectric element PZT of the sensor 72. As shown in FIG. 5, the drive voltage generation circuit 46 includes a memory 461 that stores drive waveform data supplied from the control circuit 40, and a first latch 462 that temporarily holds drive waveform data read from the memory 461. An adder 463 that adds the output of the first latch 462 and the output of a second latch 464 described later, a digital / analog converter 466 that converts the output of the second latch 464 and the second latch 464 into an analog signal. And an amplifying unit 467 that amplifies the converted analog signal and outputs a drive voltage, and a changeover switch 468 that switches the output destination of the drive voltage between the distribution output device 48 and the cartridge processing dedicated circuit 50.

  The adder 463 and the second latch 464 constitute an accumulation unit 465 that accumulates drive waveform data. Various signals are supplied from the control circuit 40 to the drive voltage generation circuit 46. That is, the memory 60 is supplied with a first clock signal CLK1, a data signal representing drive waveform data, an address signal, and an address latch signal. The first latch 462 is supplied with a second clock signal CLK2 and a reset signal RESET. The second latch 464 is supplied with a third clock signal CLK3 and a reset signal RESET. The reset signal RESET supplied to the first and second latches 462 and 464 is the same.

  The cartridge processing dedicated circuit 50 is a circuit that determines the remaining amount of ink by driving the sensors 72 provided in the ink cartridges C1 to C6 in cooperation with the control circuit 40. As shown in FIG. 6, the ink cartridge processing dedicated circuit 50 includes a calculator 51, analog switches 53, 54, S <b> 1 to S <b> 6, and an amplifier unit 52. Inside the computer 51 are a CPU 511, a PROM 512, a RAM 513, an interface 514 that exchanges signals with the control circuit 40, and an internal input / output unit (SIO) that exchanges signals with the components inside the cartridge processing dedicated circuit 50. ) 515. These are connected to each other by a bus 519. The computer 51 can exchange signals with the control circuit 40 via the interface 514. Further, the computer 51 controls the analog switches 53, 54, S1 to S6 via the SIO 515 and receives the output of the amplifier unit 52 via the SIO 515.

  Each of the analog switches 53, 54, S1 to S6 has two electrodes and is electrically disconnected from a state in which the two electrodes are electrically connected (hereinafter referred to as a connected state) according to the control of the computer 51. Switch to a state (hereinafter referred to as a cut-off state). The analog switch 53 is a switch for switching connection / disconnection between the sensor drive voltage COM2 input line and the cartridge processing dedicated circuit 50 (hereinafter referred to as a drive voltage switch). The analog switch 54 is a switch that switches connection / disconnection between an input line for inputting a signal to the amplifier unit 52 and the amplifier unit 52 (hereinafter referred to as an amplifier switch). The analog switches S1 to S6 are switches (hereinafter, referred to as ink cartridges) for selecting the ink cartridge to which the amplifier unit 52 or the sensor drive voltage COM2 and the sensor 72 (PZT) are electrically connected among the six ink cartridges C1 to C6. , Referred to as a cartridge selection switch). For example, when the cartridge selection switch S1 is in the connected state and the other cartridge selection switches S2 to S6 are in the cutoff state, the ink cartridge C1 is selected.

-Operation of the printing apparatus 20:
First, the operation of the drive voltage generation circuit 46 will be described with reference to FIGS. FIG. 7 is a timing chart showing timing for writing waveform data to the memory 461 (see FIG. 5). FIG. 8 is an explanatory diagram showing a process of generating a drive voltage in the drive voltage generation circuit 46 (see FIG. 5).

  Prior to generation of the drive voltage COM (head drive voltage COM1 or sensor drive voltage COM2), the waveform data and the address to which the waveform data is written are input from the control circuit 40 to the memory 461 as a data signal and an address signal, respectively. The data signal is a signal in 1-bit units, and is transferred bit by bit by serial transfer using the first clock signal CLK1 as a synchronization signal, as shown in FIG. That is, the waveform data is first input to the memory 461 as a data signal for a plurality of bits in synchronization with the first clock signal CLK1. Thereafter, an address signal indicating a write destination address for storing the input data signal and an address latch signal are input to the memory 461. The memory 461 reads the address signal at the timing when the address latch signal is input, and writes the waveform data input as the data signal to the address indicated by the address signal.

  After the writing of the waveform data to the memory 461 is completed, when an address signal indicating an address (hereinafter referred to as a read address) where the waveform data to be read is recorded is input to the memory 461, the memory 461 The waveform data recorded at the address is output to the first latch 461. In the example shown in FIG. 8, first, the address B is input as a read address, and the corresponding waveform data ΔV <b> 1 is output from the memory 461. Thereafter, when a pulse of the second clock signal CLK2 is generated, the output waveform data (for example, ΔV1) is held in the first latch 461. In this state, when the next pulse of the third clock signal CLK3 is generated, the output of the second latch 464 and the output of the first latch 462 are input to the adder 463 and added, and the addition result is the second. It is held by the latch 464. That is, as shown in FIG. 8, once the waveform data (for example, ΔV1) corresponding to the address signal is held in the first latch, each time the third clock signal CLK3 is received thereafter, the second data The value of the waveform data is accumulated at the output of the latch 464.

  Whenever the third clock signal CLK3 is received, the output of the second latch 464 is input to the adder 463 as described above and also to the digital / analog converter 466. Specifically, when the output of the second latch 464 is 18-bit data, the upper 10 bits are input to the digital / analog converter 466 and the entire 18-bit data is input to the adder 463 again. May be.

  The control circuit 40 measures the timing and outputs the address signal indicating the read address to the memory 461 and the second clock signal CLK2 to the first latch 462, thereby switching the waveform data held in the first latch 461. be able to.

  In the example shown in FIG. 8, it is assumed that ΔV1 is stored as waveform data at address B, ΔV2 is stored as waveform data at address A, and ΔV3 is stored as waveform data at address C. The waveform data ΔV1 takes a positive value and increases the output value of the second latch 464 by ΔV1 per cycle t of the clock signal CLK3. The waveform data ΔV2 is zero, and the output value of the second latch 464 is kept constant. The waveform data ΔV3 takes a negative value and decreases the output value of the second latch 464 by ΔV3 per cycle t of the clock signal CLK3. The control circuit 40 switches the waveform data held in the first latch 461 to ΔV1−ΔV2−ΔV3. As a result, as shown in FIG. 8A, a signal that changes in a stepwise manner ascending-maintaining-decreasing is output from the second latch 464.

  The digital / analog converter 466 converts the output signal (numerical data) of the second latch 464 continuously input into an analog signal as shown in FIG. 8B and outputs the analog signal.

  The amplifier 467 amplifies the output analog signal and generates a drive voltage that is finally output. The control circuit 40 controls the changeover switch 468 to output the generated drive voltage as the head drive voltage COM1 to the distribution output device 48 or as the sensor drive voltage COM2 to the cartridge processing dedicated circuit 50. Can be selectively switched.

  As described above, the drive voltage generation circuit 46 generates an arbitrary waveform based on the control signal from the control circuit 40 such as a data signal (waveform data (ΔV1 or the like)), an address signal, or a clock signal (CLK1 to CLK3). It is a circuit that can generate a drive voltage.

  Next, the remaining ink level determination process will be described with reference to FIGS. 9 and 10 are flowcharts showing the processing routine of the remaining ink amount determination process. In FIG. 9, for easy understanding, a flowchart of processing executed by the control circuit 40 (CPU 41) and a flowchart of processing executed by the computer 51 (CPU 511) of the cartridge processing dedicated circuit 50 are shown side by side. FIG. 11 is a timing chart showing changes in various signals and voltages in the ink remaining amount determination process.

The ink remaining amount determination processing is processing for determining the remaining amount of ink stored in the storage chamber RM of each ink cartridge C1 to C6 for each cartridge. In the printing apparatus 20 according to the present embodiment, the drive voltage generation circuit 46 serves as both a circuit that generates the head drive voltage COM1 and a circuit that generates the sensor drive voltage COM2. Therefore, this process cannot be executed when the piezo element provided in the print head 68 is driven, that is, while printing is being executed. Of course, there is no such limitation when a drive voltage generation circuit is provided exclusively for this processing. Specifically, this process is executed at the following timing.
When the ink cartridges C1 to C6 are replaced When the printing apparatus 20 is turned on After printing a certain amount (for example, after printing one page)
-After executing the process of cleaning the nozzles provided in the print head (so-called flushing process)

  When the execution of the remaining ink amount determination process is started, the control circuit 40 transmits a command to the computer 51 of the cartridge processing dedicated circuit 50 (step S201). This command includes information for designating an ink cartridge to be subjected to the remaining ink amount determination process, together with a command for instructing execution of the remaining ink amount determination process.

  The computer 51 constantly monitors whether or not a command is received from the control circuit 40 (step S101). When the command is received (step S101: YES), the processing target specified by the information included in the command Is selected (step S102). Here, the selection of the ink cartridge to be processed means that the above-described six cartridge selection switches S1 to S2 are controlled, the cartridge selection switches corresponding to the ink cartridges to be processed are connected, and the other five cartridges are selected. This refers to turning off the switch. When the ink cartridge to be processed is selected, the computer 51 stands by until the enable signal becomes high (step S103).

  After transmitting the command, the control circuit 40 sets the enable signal high at a predetermined timing and transmits it to the computer 51 (step S202). When the enable signal is set to high (step S103: YES), the computer 51 places the above-described drive voltage switch 53 in the connected state, and inputs the sensor drive voltage COM2 and the sensor 72 (piezoelectric) of the selected ink cartridge. The device is electrically connected (step S104).

  The control circuit 40 sets the enable signal to high and then controls the drive voltage generation circuit 46 (see FIG. 5) at a predetermined timing to repeat a substantially trapezoidal waveform twice as shown in FIG. 11 (details will be described later). .) Is generated and output to the cartridge processing dedicated circuit 50 (step S203). As shown in FIG. 11, the output sensor drive voltage COM2 is applied to the sensor 72 (piezoelectric element PZT) of the ink cartridge selected in step S102 described above. That is, the control circuit 40 functions as a voltage applying unit that applies the piezoelectric element driving voltage COM2 to the piezoelectric element PZT. As a result, the piezoelectric element PZT to which the sensor driving voltage COM2 is applied is rapidly distorted by the piezoelectric effect. Due to the distortion of the piezoelectric element PZT, the piezoelectric element PZT vibrates integrally with the peripheral portion. When the piezoelectric element PZT vibrates, the piezoelectric element PZT is distorted according to the vibration. When distortion occurs in the piezoelectric element PZT, a voltage is output from the piezoelectric element PZT due to the piezoelectric effect. As shown in FIG. 11, the sensor voltage (or FIG. 6: voltage at point P) shows a substantially wave-like voltage change after application of the sensor driving voltage COM2, which is output from the piezoelectric element PZT due to the piezoelectric effect. Voltage (hereinafter referred to as sensor output voltage). The frequency of the sensor output voltage corresponds to the frequency of the piezoelectric element PZT.

  The computer 51 stands by until the output (application) of the sensor drive voltage COM2 is completed (step S105), and at the timing when the application is completed, the above-described drive voltage switch 53 is turned off to provide the sensor drive voltage COM2. And the selected ink cartridge sensor 72 (piezoelectric element) are electrically disconnected. This is to prevent an erroneous application of a high voltage to the amplifier unit 52.

The computer 51 waits for a predetermined time after the drive voltage switch 53 is cut off (step S107). In FIG. 11, the period indicated by the symbol T ₂ corresponds to the standby period in this step. This standby period is a time for attenuating unnecessary vibration that causes noise among vibration components included in the vibration of the piezoelectric element PZT. During this standby period, most of the vibration components having frequencies other than the natural frequency to be detected are attenuated. As a result, as shown in FIG. 11, noise is reduced from the sensor output voltage, and the natural frequency of the piezoelectric element PZT can be easily detected.

  When the standby period has elapsed, the computer 51 places the above-described amplifier switch 54 in a connected state (step S108). As a result, the sensor output voltage described above is input to the amplifier unit 52. The amplifier unit 52 is configured by a known operational amplifier or the like, and outputs a low signal when the input voltage is a reference value V_ref (for example, 0 V) or less, and outputs a high signal when the input voltage is the reference value V_ref or more. Functions as an output comparator. As a result, the amplifier unit 52 outputs a digital signal corresponding to the periodic change of the sensor output voltage, as shown in FIG.

The computer 51 measures the frequency H of the sensor output voltage by analyzing the digital signal output from the amplifier unit 52 (step S109). Specifically, for example, the computer 51 counts clock signals included in a period T ₃ (see FIG. 11) from the rising edge E1 of the output of the amplifier unit 52 received first to the sixth rising edge E6. Then, the calculator 51 calculates the frequency H of the sensor output voltage based on the count number and the clock cycle. The frequency H of the sensor output voltage indicates the natural frequency of the piezoelectric element PZT described above.

  The computer 51 outputs the measurement result of the frequency of the sensor output voltage to the control circuit 40 (step S110), and ends this process.

  On the other hand, the control circuit 40 stands by until receiving the measurement result of the frequency of the sensor output voltage output from the computer 51 (step S204), and acquires the measurement result (step S205). Thereafter, the control circuit 40 returns the enable signal to low (step S205), and based on the obtained measurement result of the sensor output voltage frequency (the natural frequency H of the piezoelectric element PZT), the ink of the ink cartridge to be processed The remaining amount is determined (step S206).

If the natural frequency H of the piezoelectric element PZT detected as the frequency of the sensor output voltage is the above-described natural frequency H ₁ when ink is present (30 KHz in the present embodiment), the control circuit 40 will contain the accommodation room RM. Is determined to be greater than or equal to a predetermined amount (step S207). On the other hand, if the detected natural frequency H of the piezoelectric element PZT is the above-described natural frequency H ₂ without ink (in this embodiment, 110 KHz), the control circuit 40 determines the ink amount in the storage chamber RM. It is determined that the amount is less than the predetermined amount (step S208).

  Next, the waveform of the sensor drive voltage COM2 applied to the sensor 72 and the sensor output voltage corresponding to the sensor drive voltage COM2 will be described with reference to FIGS. FIG. 12 is an explanatory diagram showing an example of the waveform of the sensor drive voltage COM2. FIG. 13 is an explanatory diagram showing sensor output voltage characteristics in the frequency domain. FIG. 14 is an explanatory diagram showing sensor output voltages in the frequency domain when ink is present and when ink is absent.

FIG. 12A shows a waveform having only one waveform (hereinafter referred to as a unit waveform) including a charging period and a discharging period (hereinafter also referred to as a single waveform). In the unit waveform, the voltage does not change during a period in which the voltage rises from GND (0 V) to a predetermined voltage value (for example, 36 V) (time t ₁ to time t ₂ : a period in which the piezoelectric element PZT is charged). A period (time t ₂ to time t ₃ : a period in which electric charge is held in the piezoelectric element PZT) and a period in which the voltage drops from a predetermined voltage value (for example, 36 V) to GND (0 V) (time t ₃ to time t ₄ ) A substantially trapezoidal waveform.

FIG. 12B shows the waveform of the sensor drive voltage COM2 used in this embodiment. This waveform is a waveform obtained by repeating the unit waveform described above twice at a predetermined cycle (hereinafter also referred to as a twice waveform). The predetermined cycle is the same cycle as the vibration cycle at the natural frequency H ₁ when ink is present, and is a 1 / H ₁ (sec) cycle as shown in FIG.

FIG. 12C shows a waveform obtained by repeating the unit waveform described above three times at the same 1 / H ₁ (sec) cycle as the two-time waveform (hereinafter also referred to as a three-time waveform).

  A difference in sensor output voltage when the voltages of the one-time waveform, the second-time waveform, and the third-time waveform are applied to the sensor 72 as sensor drive voltages will be described. The output voltage characteristics shown in FIG. 13 are a two-time waveform and a three-time waveform, where a sensor output voltage (referred to as a sensor output voltage corresponding to a one-time waveform) when a sensor drive voltage having a one-time waveform is applied to the sensor is 1. The relative values of the sensor output voltages (referred to as sensor output voltages corresponding to the two-time waveform and the three-time waveform, respectively) when the sensor drive voltage is applied are shown in the frequency domain.

The sensor output voltage corresponding to the twice waveform is higher than the sensor output voltage corresponding to the once waveform in the frequency region centered on the frequency H ₁ . On the other hand, the sensor output voltage is lower than the sensor output voltage corresponding to the one-time waveform in a frequency region away from the frequency H ₁ (eg, a region near the frequency H ₂ ).

The sensor output voltage corresponding to the three-time waveform is further increased from the sensor output voltage corresponding to the two-time waveform in the frequency region centered on the frequency H ₁ . However, the increasing frequency region is narrower than the twice waveform. In other words, assuming that the sensor output voltage characteristics corresponding to the two-time waveform and the three-time waveform can be expressed by a normal distribution function, the variance of the sensor output voltage characteristics corresponding to the two-time waveform is the sensor output corresponding to the three-time waveform. This means that the voltage characteristic is larger than the variance. Then, the sensor output voltage is further lowered from the sensor output voltage corresponding to the waveform twice in a frequency region away from the frequency H ₁ (for example, a region near the frequency H ₂ ).

This is repeated several times the unit waveform in the same period as that of the vibration in the natural frequency H _1, the component of the frequency H ₁ corresponding to the natural frequency H ₁ included in the sensor drive voltage COM2 is increased, conversely This is because frequency components (for example, components of frequency H ₂ ) corresponding to frequencies other than the natural frequency H ₁ are reduced.

Next, the sensor output voltage in the frequency domain when ink is present (FIG. 14 (a)) and when ink is absent (FIG. 14 (b)) will be described with reference to FIG. First, the sensor output voltage (represented by wavy lines in FIGS. 14A and 14B) corresponding to the one-time waveform (unit waveform) will be described. According to experiments, when ink is present, that is, when the natural frequency of the piezoelectric element PZT is H ₁ , the sensor output voltage corresponding to the one-time waveform has a frequency H corresponding to the natural frequency H ₁ to be detected. The component ₁ is small and buried in the surrounding noise, and it may be difficult to accurately measure the frequency H ₁ . On the other hand, when there is no ink, that is, when the natural frequency of the piezoelectric element PZT is H ₂ , the sensor output voltage corresponding to the one-time waveform has the frequency H ₂ corresponding to the natural frequency H ₂ to be detected. The component was sufficiently large and showed a peak about 3 to 4 times the component of the frequency H ₁ when the ink was present. This is the single waveform (unit waveform) has less component of the frequency H ₁ corresponding to the natural frequency H _1, can not be sufficiently resonate at the natural frequency H ₁ the piezoelectric element PZT during ink-present It is shown that. On the other hand, the single waveform (unit waveform) is sufficiently the component of the frequency H ₂ corresponding to the natural frequency H ₂ many be sufficiently resonate at the natural frequency H ₂ the piezoelectric element PZT during no ink It shows that you can.

Next, sensor output voltages corresponding to the two-time waveform (shown by solid lines in FIGS. 14A and 14B) will be described. According to experiments, when ink is present, the sensor output voltage corresponding to the twice waveform is sufficiently larger than the component of the frequency H ₁ corresponding to the natural frequency H ₁ to be detected compared to the one-time waveform. Thus, the frequency H ₁ can be measured with sufficient accuracy. On the other hand, when there is no ink, the sensor output voltage corresponding to the two-time waveform is smaller than the case where the component of the frequency H ₂ corresponding to the natural frequency H ₂ to be detected is one-time waveform, It was still a level sufficient to accurately measure the frequency H _2. As a result, in the sensor output voltage corresponding to the two-time waveform, the frequency H ₁ component when ink is present and the frequency H ₂ component when ink is absent are approximately the same. This is because the unit waveform is repeated a plurality of times at the same period as the vibration period at the natural frequency H ₁ , and the twice-time waveform has an increased frequency H ₁ component and a frequency H ₂ component compared to the unit waveform. Therefore, it can be considered that the waveform includes the component of the frequency H _{1 and} the component of the frequency H _{2 in} a well-balanced manner. As a result, the two-time waveform can sufficiently resonate the piezoelectric element PZT at the natural frequency H ₁ when ink is present, and sufficiently resonate the piezoelectric element PZT at the natural frequency H ₂ even when ink is absent. It is thought that it can be made.

Furthermore, for comparison, sensor output voltages corresponding to the three-time waveform (shown by solid lines in FIGS. 14A and 14B) will be described. According to experiments, when ink is present, the sensor output voltage corresponding to the three-time waveform is further compared to the case where the component of the frequency H ₁ corresponding to the natural frequency H ₁ to be detected is twice the waveform. It ’s bigger. On the other hand, when there is no ink, the sensor output voltage corresponding to the three-time waveform is further reduced as compared with the case where the frequency H ₂ component corresponding to the natural frequency H ₂ to be detected is a one-time waveform. In some cases, it is buried in the surrounding noise and it is difficult to accurately measure the frequency H ₁ . This indicates that the three-time waveform has a further increased frequency H ₁ component compared to the two-time waveform, and can sufficiently resonate the piezoelectric element PZT at the natural frequency H ₁ when ink is present. Yes. On the other hand, in the three-time waveform, the frequency H ₂ component is further reduced compared to the two-time waveform, and the piezoelectric element PZT cannot be sufficiently resonated at the natural frequency H ₂ when there is no ink. It shows that.

Based on the above knowledge, in this embodiment, the above-described two-time waveform is adopted, and both the natural frequency H ₁ when ink is present and the natural frequency H ₂ when ink is absent can be detected with high accuracy.

As described above, according to the printing apparatus 20 according to the present embodiment, the waveform of the sensor driving voltage COM2 is adjusted so as to have a waveform including a lot of frequency components corresponding to the natural frequency H ₁ , so that the ink has a natural vibration. In the state corresponding to the number H ₁ , the frequency component corresponding to the natural frequency H 1 can be sufficiently increased in the sensor output voltage, and the natural frequency H 1 is reliably set as the frequency of the sensor output voltage. Can be detected. Then, it is possible to accurately determine that the ink corresponds to the natural frequency H ₁ , that is, that the amount of ink in the storage chamber RM is equal to or greater than a predetermined amount.

Further, the waveform of the sensor driving voltage COM2, in the same period as that of the vibration corresponding to the natural frequency H _1, by a waveform repeating unit waveform, the natural frequency H ₁ included in the waveform of the sensor driving voltage COM2 The frequency component corresponding to can be easily increased.

Further, the waveform of the sensor drive voltage COM2 is adjusted to include a lot of frequency components corresponding to the natural frequency H ₁ and also to include a lot of frequency components corresponding to the natural frequency H _2. in the case where a state corresponding to the frequency H ₂ also, the component of the frequency corresponding to the natural frequency H ₂ in the sensor output voltage can be sufficiently increased, securely sensor output voltage and the natural frequency H ₂ It can be detected as a frequency. Then, it is possible to accurately determine not only the state in which the ink corresponds to the natural frequency H ₁ but also the state in which the ink corresponds to the natural frequency H ₂ , that is, whether the ink in the storage chamber RM is less than the predetermined amount. it can.

  Furthermore, since the generation of the sensor drive voltage COM2 is generated by the drive voltage generation circuit 46 capable of generating a voltage having an arbitrary waveform, it is possible to easily generate a sensor drive voltage including a large amount of a predetermined frequency component. .

  The head drive voltage COM1 and the sensor drive voltage COM2 used for driving the print head 68 are realized by one drive voltage generation circuit 46. Therefore, the number of parts does not increase in order to generate the sensor drive voltage COM2.

B. Variations:
In addition to the ink cartridges C1 to C6 described in the above embodiments, various aspects of the configuration of the ink cartridge such as the arrangement of the sensor 72 are conceivable. A specific example will be described below.
Other aspects of the ink cartridge:
A schematic configuration of the printing apparatus and the ink cartridge according to this modification will be described with reference to FIGS. 15 and 16. FIG. 15 is a front view (FIG. 16A) and a side view (FIG. 16B) of ink cartridges C1 to C6 according to a modification. FIG. 16 is a cross-sectional view showing a cross-section (cross-section AA in FIG. 15) of the sensor mounted on the casing of the ink cartridge.

  As shown in FIG. 15, the ink cartridges C <b> 1 to C <b> 6 according to the modification include a casing 71, an ink supply port 74, a sensor 72, and a terminal plate 110 in the same manner as the ink cartridges C <b> 1 to C <b> 6 according to the above embodiment. (The terminal board 110 is not shown in FIG. 15A).

  Unlike the ink cartridges C1 to C6 according to the above-described embodiment, the inside of the casing 71 of the ink cartridges C1 to C6 according to the modified example includes a main storage chamber MRM, a first sub storage chamber SRM1, and a partition rib 77. It is partitioned into a second sub-accommodating chamber SRM2. The main storage chamber MRM occupies most of the total storage chamber volume.

  The first sub-accommodating chamber SRM1 communicates with the ink supply port 74 on the bottom surface (see FIG. 15). Further, the first sub-accommodating chamber SRM1 communicates with the bridge flow path BR formed in the sensor attachment 722 of the sensor 72 through the first side surface hole 75 formed in the side surface of the housing 71 ( (See FIG. 16).

  The second sub storage chamber SRM2 communicates with the main storage chamber MRM near the bottom surface (see FIG. 15). The second sub-accommodating chamber SRM2 communicates with a bridge channel BR formed in the sensor attachment 722 of the sensor 72 via a second side hole 76 formed in the side surface of the casing 71 ( (See FIG. 16).

  As shown in FIG. 16, the sensor 72 includes a piezoelectric element PZT, electrodes 720 and 721, and a sensor attachment 722, similar to the sensor 72 according to the above embodiment. The sensor attachment 722 has a different shape from the sensor attachment 722 according to the above-described embodiment, and the bridge flow path BR described above is formed in a substantially U-shape as shown in FIG. The bridge channel BR has one end communicating with the first side hole 75 and the other end communicating with the second side hole 76. Thus, ink can flow from the second sub-accommodating chamber SRM2 into the first sub-accommodating chamber SRM1.

  The ink stored in the ink cartridges C1 to C6 according to the modified example moves as indicated by arrows in FIGS. 15 and 16. That is, the ink stored in the main storage chamber MRM enters the second sub storage chamber SMR2 from the vicinity of the bottom surface, and passes through the second side surface hole 76—the bridge flow path BR of the sensor attachment 722—the first side surface hole 75. And enters the first sub-accommodating chamber SMR1. Then, the ink is supplied to the printer 20 from the first sub storage chamber SMR1 through the ink supply port 74.

  FIG. 16A shows a state where a predetermined amount or more of ink remains (when ink is present). FIG. 16B shows a state in which less than a predetermined amount of ink remains (when there is no ink). As shown in FIG. 16A, when the amount of ink in the ink storage chamber RM is equal to or greater than a predetermined amount, the above-described bridge flow path BR is filled with ink. That is, the peripheral portion of the piezoelectric element PZT is filled with ink. On the other hand, when the amount of ink in the ink storage chamber RM is less than a predetermined amount, the ink does not flow from the second sub storage chamber SRM2 into the bridge flow path BR, and the bridge flow path BR is not filled with ink. . That is, the peripheral portion of the piezoelectric element PZT is not filled with ink. As a result, like the ink cartridge in the above embodiment, the piezoelectric element PZT vibrates at different natural frequencies when ink is present and when ink is absent. As a result, also in the printing apparatus 20 using the ink cartridge according to the modification, it is possible to obtain the same operation and effect as the printing apparatus according to the above-described embodiment.

・ Other variations:
In the above embodiment, the waveform of the sensor drive voltage COM2 repeats the unit waveform with the same period as the vibration period at the natural frequency H _1. However, the repetition period is not limited to this, and an arbitrary period is used. Can be used. As a result, the frequency component corresponding to an arbitrary frequency can be increased in the sensor output voltage. For example, depending on the shape of the unit waveform, the vibration characteristics of the cartridge, etc., it may be desired to generate a waveform with an increased frequency component corresponding to the natural frequency H ₂ when no ink is used. In such a case, as shown in FIG. 17 (a) (b), may be repeated unit waveform in the same period as that of the vibration in the natural frequency H _2. This way, the sensor drive voltage COM2 with many waveform frequency component corresponding to the natural frequency H ₂ can be easily produced, as illustrated in FIG. 17 (c), the sensor output voltage, the natural frequency The frequency H ₂ component corresponding to the number H ₂ can be increased.

In the above-described embodiment, the waveform of the sensor drive voltage COM2 is a waveform that can detect the natural frequency H _{1 when there} is ink and the natural frequency H ₂ when there is no ink by a single measurement. The measurement of the natural frequency H _{1 and} the measurement of the natural frequency H ₂ without ink may be performed in two steps. In such a case, in the measurement of the natural frequency H ₁ at the time of ink-present, the sensor output voltage with a waveform shown in FIG. 12, to increase the component of the frequency H ₁ corresponding to the natural frequency H _1, ink in the measurement of the natural frequency of H ₂ at no, in the sensor output voltage with a waveform shown in FIG. 17, it is sufficient to increase the component of the frequency H ₂ corresponding to the natural frequency H _2. In such a case, since it is not necessary to consider the decrease in the other frequency component, the number of repetitions may be further increased (for example, a 4-time waveform, a 5-time waveform, etc. may be used).

The natural frequency H ₁ of the piezoelectric element PZT of the ink cartridge may not be constant due to manufacturing variations. In such a case, the repetition period may be determined using a statistical value of manufacturing variation, for example, an average value or an intermediate value of natural frequencies. Further, the ink cartridge may be provided with a memory that measures the natural frequency and stores the measured natural frequency at the time of manufacture. In such a case, the control circuit of the printing apparatus can read the value of the natural frequency from the memory, and determine the repetition cycle based on this value.

In the above embodiment, whether the ink is less than the predetermined amount or more than the predetermined amount is determined by detecting the natural frequency H ₁ of the piezoelectric element PZT of the ink cartridge. If the natural frequency of the piezoelectric element PZT changes, the various states of the ink can be detected.

  As mentioned above, although this invention was demonstrated based on the Example and the modification, Embodiment mentioned above is for making an understanding of this invention easy, and does not limit this invention. The present invention can be changed and improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present invention.

1 is a schematic configuration diagram of a printing apparatus 20 as an embodiment of the present invention. FIG. 3 is a perspective view showing a print head unit and an ink cartridge according to the present embodiment attached to the print head unit. FIG. 4 is a cross-sectional view showing a cross section of a sensor installed in a casing of an ink cartridge. FIG. 3 is an explanatory diagram showing an internal configuration of a control circuit 40. 4 is an explanatory diagram showing an internal configuration of a drive voltage generation circuit of the control circuit 40. FIG. 4 is an explanatory diagram showing an internal configuration of a cartridge processing dedicated circuit 50. FIG. The timing chart which shows the timing which writes waveform data in the memory 461. Explanatory drawing which shows the process which produces | generates a drive voltage in the drive voltage generation circuit 46 FIG. 6 is a first flowchart illustrating a processing routine of ink remaining amount determination processing. FIG. 7 is a second flowchart showing a processing routine of ink remaining amount determination processing. 6 is a timing chart showing changes in various signals and voltages in the ink remaining amount determination process. The 1st explanatory view showing an example of the waveform of sensor drive voltage COM2. Explanatory drawing which shows the sensor output voltage characteristic in a frequency domain. Explanatory drawing which shows the sensor output voltage in the frequency domain at the time of ink presence and absence of ink. The front view and side view of the ink cartridges C1-C6 which concern on a modification. Sectional drawing which shows the cross section of the sensor with which the housing | casing of the ink cartridge which concerns on a modification was equipped. The 2nd explanatory view showing an example of the waveform of sensor drive voltage COM2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Printing apparatus 22 ... Paper feed motor 23 ... Gear train 24 ... Carriage motor 26 ... Platen 30 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... Pulley 39 ... Position sensor 40 ... Control circuit 46 ... Drive Voltage generation circuit 50... Dedicated cartridge processing circuit 51... Calculator 53, 54, S1 to S6... Analog switch 52... Amplifier section 80... PC interface 60 ... print head unit 62 ... cartridge mounting section 66. C6 ... Ink cartridge 71 ... Housing 72 ... Sensor 74 ... Ink supply port 75 ... First side hole 76 ... Second side hole 77 ... Partition rib 90 ... Computer
DESCRIPTION OF SYMBOLS 100,110 ... Terminal board 104, 105, 114, 115 ... Terminal RM ... Ink storage chamber MRM ... Main storage chamber SRM1 ... First sub storage chamber SRM2 ... Second sub storage chamber PZT ... Piezoelectric element

Claims (6)

A printing device,
A printing material having a storage chamber in which a printing material is stored, a supply port for supplying the printing material to the printing apparatus, and a bridge channel for flowing the printing material from the storage chamber to the supply port A containing body;
A piezoelectric element disposed on one side of the bridge channel ;
The frequency component corresponding to the first natural frequency of the piezoelectric element when the printing material is present in the bridge flow path, and the second natural vibration of the piezoelectric element when the printing material is not present in the bridge flow path. a voltage generating means for generating a piezoelectric element drive voltage having a waveform including many both a frequency component corresponding to the number, the,
Voltage applying means for applying the generated piezoelectric element driving voltage to the piezoelectric element to vibrate the piezoelectric element;
Frequency measuring means for measuring the frequency of the voltage output by the piezoelectric effect from the vibrating piezoelectric element after application of the piezoelectric element driving voltage;
When the frequency of the piezoelectric element detected as the frequency of the voltage is the first natural frequency, it is determined that the printing material in the printing material container is greater than or equal to a predetermined amount, and the frequency is If the second natural frequency, the state determination means for determining that the printing material in the printing material container is less than a predetermined amount ,
The frequency component corresponding to the first natural frequency included in the unit waveform including the voltage increase and the voltage decrease is less than the frequency component corresponding to the second natural frequency included in the unit waveform. ,
The voltage generating means generates a waveform that repeats the unit waveform a plurality of times at the same cycle as the cycle of vibration at the first natural frequency, as the waveform of the piezoelectric element drive voltage. The printing apparatus according to claim 2 ,
The printing apparatus is a voltage generation circuit capable of generating a voltage having an arbitrary waveform. The printing apparatus according to claim 1 or 2 , further comprising:
A print head that performs printing by applying a drive voltage;
Switching means for switching the output destination of the voltage generated by the voltage generation means to either the print head or the piezoelectric element;
The voltage generating unit is a printing apparatus that also functions as a unit that generates a head driving voltage applied to the print head. The printing device according to any one of claims 1 to 3,
The printing apparatus, wherein the printing material container is a container that can be attached to and detached from the printing apparatus. In the printing apparatus as described in any one of Claim 1- Claim 4,
The printing apparatus, wherein the voltage generation unit generates a waveform that repeats the unit waveform twice at the same period as the period of vibration at the first natural frequency as the waveform of the piezoelectric element driving voltage. A method of detecting a state of a printing material accommodated in the printing material container using a piezoelectric element provided in the printing material container,
The printing material container includes a storage chamber in which a printing material is stored, a supply port for supplying the printing material to a printing apparatus, and a bridge channel for flowing the printing material from the storage chamber to the supply port. And having
The piezoelectric element is disposed on one side of the bridge channel,
(A) a frequency component corresponding to the first natural frequency of the piezoelectric element when a printing material is present in the bridge flow path, and a second of the piezoelectric element when the printing material is not present in the bridge flow path . generating a piezoelectric element drive voltage having both much including waveform frequency component corresponding to the natural frequency of,
A step of vibrating the piezoelectric element (b) applying a piezoelectric element drive voltage the generated in said piezoelectric element,
(C) after application of the piezoelectric element drive voltage, a step of measuring the frequency of the voltage output by the piezoelectric effect of said piezoelectric element to vibrate,
(D) When the frequency of the frequency of the piezoelectric element detected as the frequency of the voltage is the first natural frequency, it is determined that the printing material in the printing material container is greater than or equal to a predetermined amount. And determining that the printing material in the printing material container is less than a predetermined amount when the frequency is the second natural frequency,
The frequency component corresponding to the first natural frequency included in the unit waveform including the voltage increase and the voltage decrease is less than the frequency component corresponding to the second natural frequency included in the unit waveform. ,
In the step (a), as the waveform of the piezoelectric element driving voltage, a waveform is generated that repeats the unit waveform a plurality of times at the same period as the period of vibration at the first natural frequency.

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