Patent Publication Number: US-7909444-B2

Title: Liquid discharge cartridge and liquid discharge apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a division of application Ser. No. 11/101,541, filed Apr. 8, 2005, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid discharge cartridge with the structure of having a liquid discharge element and a switching circuit, including a liquid discharge head applicable to an apparatus used for the production of a DNA chip, an organic transistor, a color filter, or the like, and a liquid container which contains liquid supplied to this. The liquid discharge head discharges liquid by injecting energy into a liquid discharge element and makes liquid droplets adhere on a medium, and in particular, relates to an ink jet recording head using ink as the liquid. 
     2. Related Background Art 
     A liquid discharge apparatus will be explained with an example of an ink jet recording apparatus. One of structures of detecting residual ink amount in an ink tank in a conventional ink jet recording apparatus (ink jet printer) will be explained. First, the change of the electrostatic capacitance which varies according to ink residual amount is converted into an output signal (pulse signal) in an oscillation circuit provided in a CR circuit, and is outputted. The output signal is inputted into a central processing unit (hereinafter, a “CPU”) of a host computer which controls the printer. Then, the structure of detecting the change of a frequency of the pulse signal and detecting the residual ink amount in the CPU is known. 
     In this conventional structure, since the output signal outputted from the oscillation circuit is directly inputted into the CPU of the host computer, there is a problem that the processing burden of the CPU of the host computer becomes heavy. 
     Then, in order to solve this problem, the structure relating to Japanese Patent Application Laid-Open No. H10-100447 has been proposed. 
       FIG. 10  is a circuit diagram of residual ink amount detection equipment shown in the above-mentioned gazette. A signal A is outputted from an electrostatic detection circuit  1051  where an oscillation frequency varies according to the residual ink amount in an ink tank  1057 . Then, a signal B is outputted from a reference signal generating circuit  1039 . The logical operation of them is performed in a NAND circuit  1040 , and the CPU compares an output signal C of the NAND circuit  1040  to the signal B. Thereby, the load of the CPU is reduced in comparison to the structure that the output signal outputted from the oscillation circuit is directly inputted into the CPU of the host computer. Then, it becomes possible to enhance processing speed as a whole. 
     In addition, some printers are constituted so as to count the number of times of discharge of ink by each CPU and may estimate residual ink amount. An ink jet unit being equipped with an memory element in which the number of drive pulses expressing the number of times of ink discharge and the number of times of suction recovery treatment are written is disclosed in Japanese Patent Application Laid-Open No. H09-314861.  FIG. 11  is a drawing showing in multiple the structure of a conventional ink jet unit shown in the above-mentioned gazette. 
     The ink jet unit shown in  FIG. 11  is formed by integrating a head  2010  and an ink tank  2014 . This unit is mounted detachably in a carriage (not shown) of a recording apparatus. In the drawing, a memory element  2011  is constituted of, for example, EEPROM (Electrically Erasable Programmable Read-only Memory) which is nonvolatile memory. The memory element  2011  is mounted on a PCB substrate  2012 , and a plurality of heat-generating resistors (not shown) are provided on a silicon substrate  2013  corresponding to the number of ink ejection orifices. The silicon substrate  2013  and PCB substrate  2012  are electrically connected by wire bonding. A terminal  2015  is provided in an end portion of the PCB substrate  2012 , and electrically connects a head  2010  to an apparatus body. When being mounted in the carriage, the ink jet unit is connected to a connector provided on the carriage. The head  2010  is equipped with the above-mentioned respective elements. On the other hand, an ink tank  2014  stores ink supplied to the head  2010 . 
     According to this structure, the number of drive pulses expressing the number of times of ink discharge, and the number of times of suction recovery treatment are written in the memory element  2011  in the head  2010 . Thus, accumulated values such as the number of drive pulses relating to ink amount consumed by the head  2010  are stored. In order to know residual ink amount, data is first fetched from the memory element  2011  by read and write means provided in the recording apparatus. Then, a CPU of the recording apparatus or the like subtracts ink consumption corresponding to the number of drive pulses and the number of times of suction recovery treatment, which are recorded in the data, from the initial ink amount of the ink tank  2014 . Owing to this, it becomes possible to know the residual ink amount in the ink tank  2014 . In addition, when the memory element  2011  is nonvolatile memory such as EEPROM, the information stored in the memory element  2011  is not erased even if the ink jet unit is removed from the recording apparatus. 
     In addition, U.S. Pat. No. 6,719,394 discloses the structure of arranging a ball-shaped semiconductor device in the interior or exterior of a container such as an ink tank, and detecting information inside the ink tank. This device is equipped with energy conversion means, information acquisition means of acquiring environmental information around the device, and judgment means. Furthermore, the device is equipped with information storage means of accumulating information for being compared with the information, acquired by the information acquisition means, by the judgment means, and information transmission means  18  of transmitting the acquired information to the outside by the judgment of the judgment means  16 . 
     Nevertheless, the conventional residual ink amount detection equipment shown in  FIG. 10  cannot detect the residual ink amount without using the CPU of the host computer. Therefore, a processing burden arises in the CPU of the host computer, and in order to detect the residual ink amount, a user has to start both the host computer and recording apparatus, and hence, this is inconvenient for a user. Nevertheless, when the processing capability currently performed by the CPU is separately installed in the recording apparatus in order to detect the residual ink amount, the cost of the recording apparatus increases. 
     In addition, in the structure of counting the number of times of discharge of ink and estimating the residual ink amount by a CPU of a recording apparatus as shown in  FIG. 11 , a processing burden also arises in the CPU of the recording apparatus. 
     In addition, in the structure in U.S. Pat. No. 6,719,394, it is necessary separately to provide a three-dimensional semiconductor device. Furthermore, since a drive power supply also has the structure of converting external force and the like into energy by energy conversion means, structure is complicated, and hence, the further simplification of a detection system is required. 
     Then, the present invention aims at providing a liquid discharge cartridge with the structure that information about the presence of residual liquid amount stored in the memory of the liquid discharge cartridge is not erased even if the liquid discharge cartridge is removed from a liquid discharge apparatus, and that a processing burden is not made to arise in a CPU of a host computer or the liquid discharge apparatus. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above-described objects, in a liquid discharge cartridge having a liquid discharge head discharging liquid, and a liquid container containing the liquid supplied to the liquid discharge head, a liquid discharge cartridge of the present invention is characterized in that a sensor for detecting the residual liquid amount in the liquid container is provided in the liquid container, and that the liquid discharge head includes detection means of detecting the residual liquid amount in the liquid container using the sensor, judgment means of judging the presence of the residual liquid amount in the liquid container on the basis of an output from the detection means, and outputting zero residual liquid amount information when judging that there is no residual liquid amount in the liquid container, and nonvolatile memory means of storing the zero residual liquid amount information when the zero residual liquid amount information is outputted from the judgment means. 
     In the liquid discharge cartridge of the present invention, the detection means detects residual liquid amount in the liquid container by the sensor provided in the liquid container, and outputs a signal, having correlation in the residual liquid amount, to the judgment means. The judgment means judges the presence of the residual liquid amount in the liquid container on the basis of an output from the detection means, and outputs information having correlation to zero residual liquid amount (zero residual liquid amount information) to the nonvolatile memory means. The nonvolatile memory means stores this when the zero residual liquid amount information is inputted from the judgment means. In this way, when it is detected that the residual liquid amount in the liquid container is zero, zero residual liquid amount information is stored in the nonvolatile memory means. 
     Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram showing a liquid discharge cartridge according to a first embodiment of the present invention; 
         FIG. 2  is a schematic structural diagram showing a liquid discharge cartridge according to a second embodiment of the present invention; 
         FIG. 3  is a block diagram showing one configuration example of an oscillation circuit shown in  FIG. 2 ; 
         FIG. 4  is a block diagram showing one configuration example of a judgment circuit shown in  FIG. 2 ; 
         FIG. 5  is a block diagram showing one configuration example of a one-time ROM shown in  FIG. 2 ; 
         FIGS. 6A and 6B  are operation timing charts of the judgment circuit shown in  FIG. 4 ; 
         FIG. 7  is a drawing for explaining a discharge unit in one embodiment of a liquid discharge cartridge of the present invention; 
         FIG. 8  is a perspective view showing the structure of the liquid discharge head where the discharge unit shown in  FIG. 7  is incorporated; 
         FIG. 9  is a perspective view showing the schematic configuration of an ink jet recording apparatus which is one embodiment of a liquid discharge apparatus to which a liquid discharge cartridge according to the present invention is applied; 
         FIG. 10  is a circuit diagram of residual ink amount detection equipment by conventional art; and 
         FIG. 11  is a drawing showing in multiple the structure of a conventional ink jet unit. 
     
    
    
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Next, embodiments of the present invention will be described with referring to drawings. 
     First Embodiment 
     In this embodiment, a liquid discharge apparatus will be explained with an example of an ink jet recording apparatus.  FIG. 1  is a schematic structural diagram showing a liquid discharge cartridge according to a first embodiment of the present invention. 
     A head cartridge  1  of this embodiment has the structure that a print head  3  and an ink tank  2  which are formed separately are integrated. In the ink tank  2 , a sensor  4  detecting residual ink amount in the ink tank  2  is provided. A signal outputted from the sensor  4  is inputted into a detection circuit  5  provided in the print head  3 . An output from the detection circuit  5  is inputted into a judgment circuit  6  similarly provided in the print head  3 , and an output from the judgment circuit  6  is inputted into nonvolatile memory  7  similarly provided in the print head  3 . 
     The print head  3  is equipped with, for example, an ink ejection mechanism (not shown) including a nozzle which has a heat-generating resistor, which is an electrothermal converting element, and an ink ejection orifice, and a switching circuit (not shown) using a transistor which controls the injection and cutoff of energy to this ink ejection mechanism. Generally, such the print head  3  is constituted on a silicon substrate using semiconductor manufacturing process. Hence, it is possible to constitute the detection circuit  5 , judgment circuit  6 , and nonvolatile memory  7 , which are mentioned above, on the silicon substrate. It is also possible to form these detection circuit  5 , judgment circuit  6 , and nonvolatile memory  7  monolithically on the same silicon substrate that forms a heater board on which the heat-generating resistor is formed. Thereby, it is possible to realize simple circuitry in comparison with the case that each circuit is constituted separately. In addition, a recording apparatus where the head cartridge is used is equipped with a control section (CPU) which supplies a drive control signal to the heat-generating resistor which is an electrothermal converting element. 
     Next, the detecting operation of residual ink amount by the head cartridge of this embodiment will be explained. 
     The detection circuit  5  of the print head  3  detects the presence of residual ink amount in the ink tank  2  by the sensor  4  located in the ink tank  2 . The detection circuit  5  outputs a signal, correlating to the presence of residual ink amount, to the judgment circuit  6 . The judgment circuit  6  judges from the signal, outputted from the detection circuit  5 , whether the residual ink amount is zero. When judging that the residual ink amount is zero, the judgment circuit  6  records the information (ink zero information), correlating to the residual ink zero amount, in the nonvolatile memory  7 . The judgment circuit  6  does not record information on the nonvolatile memory  7  when judging that the residual ink amount is not zero. The ink zero information stored in the nonvolatile memory  7  can be read, for example, by a read/write section (not shown) of a printer body. In addition, “residual ink amount is zero” includes not only the case that there is no residual ink amount in the ink tank  2  completely, but also the case that the residual ink amount in the ink tank  2  is less than predetermined amount. 
     It is no matter that the timing of detecting the residual ink amount in the ink tank  2  by the sensor  4  and detection circuit  5  which are mentioned above is on waiting or during the recording operation of a printer. When the ink zero information is read from the nonvolatile memory  7 , the printer body outputs an information signal including a message of that ink in the ink tank  2  became empty to inform a user of the printer of this. This message may be communicated to the user by being displayed on a display unit (not shown) of the printer body, or also by being displayed on a display unit connected to a host computer (personal computer) which controls the printer. 
     According to the structure of this embodiment, the sensor  4 , detection circuit  5 , judgment circuit  6 , and nonvolatile memory  7  which constitute the circuit closed within the head cartridge  1  can detect the presence of the residual ink amount in the ink tank  2 . As mentioned above, these detection circuit  5 , judgment circuit  6 , and nonvolatile memory  7  are constituted on the silicon substrate of the print head  3  using the semiconductor manufacturing process. Hence, it is possible to reduce manufacturing cost in comparison with the case that they are constituted separately on a circuit board of the printer body. In addition, according to the structure of this embodiment, it is possible to detect residual ink amount without using a CPU of a host computer. Hence, since the residual ink amount is detectable so long as only the printer body is started, it is possible to increase convenience for a user. In addition, since it is not necessary to provide a three-dimensional semiconductor device for detection in an ink tank separately, structure becomes simple. 
     Furthermore, since the head cartridge  1  in itself is equipped with the nonvolatile memory  7  in this embodiment, information is stored in the nonvolatile memory  7  as it is, even if it is removed from the printer body once and is mounted on the printer body again. Therefore, it is detectable whether the ink tank  2  of the head cartridge  1  which is mounted on the printer body is empty, by reading in the read/write section of the printer body whether ink zero information is stored in the nonvolatile memory  7 . What was performed in a conventional printer was the sequence of detecting residual ink amount in an ink tank of a head cartridge when the head cartridge was newly mounted in a printer body. According to this embodiment, it is possible to detect the residual ink amount without performing such sequence. Thereby, it is possible promptly to inform a user of that there is no residual ink amount, and further, it is possible to shorten recording operation time of the printer by the time which sequence operation needs. 
     Second Embodiment 
       FIG. 2  is a schematic structural diagram showing a head cartridge according to a second embodiment of the present invention. 
     A head cartridge  11  of this embodiment also has the structure that a print head  13  and an ink tank  12  which are formed separately are integrated, similarly to the first embodiment. In the ink tank  12 , three plate-like electrodes  14   a ,  14   b , and  14   c  which function as a sensor which detects the presence of residual ink amount in the ink tank  12  are provided. The print head  13  has an oscillation circuit  15  which outputs a signal S 1  obtained when a pulse signal at a predetermined frequency is inputted into the first electrode  14   a , a judgment circuit  16  where the output signal S 1  from the oscillation circuit  15  and a control signal S 0  from a control section (not shown) of a printer body are inputted, and one-time ROM  17  into which the output from the judgment circuit  16  is inputted. These oscillation circuit  15 , judgment circuit  16 , and one-time ROM  17  are constituted on a silicon substrate of the print head  13  using the semiconductor manufacturing process. In addition, the one-time ROM is ROM (Read Only Memory) in which information can be written only once. 
     The electrodes  14   a ,  14   b , and  14   c  of the ink tank  12  will be explained. The first electrode  14   a  and second electrode  14   b  out of the three electrodes are embedded inside a wall of the ink tank  12  with leaving a space between themselves. The oscillation circuit  15  is connected to the first electrode  14   a , and the second electrode  14   b  is connected to GND potential. The third electrode  14   c  is provided in an electrode supporting section  12   a  which is made of the same material (plastics etc.) as that of a wall member of the ink tank  12 . The electrode supporting section  12   a  is extended from the bottom of the ink tank  12  with leaving a gap d between with a wall portion of the ink tank  12  so that the electrode supporting section  12   a  may cover the two electrodes  14   a  and  14   b  provided in the wall portion of the ink tank  12 . 
     The gap d is a gap between the wall portion of the ink tank  12  and electrode supporting section  12   a . It is necessary to secure such a gap that ink flows in freely between the electrodes  14   a  and  14   b  provided in the wall portion of the ink tank  12 , and the electrode  14   c  provided in the electrode supporting section  12   a.    
     In addition, arrangement places of the electrodes  14   a ,  14   b , and  14   c  may be places where ink can flow in between the electrodes  14   a  and  14   b , and electrode  14   c , and where ink does not exist in the gap d between the electrodes  14   a  and  14   b , and electrode  14   c  when the residual ink amount in the ink tank  12  becomes zero or becomes less than predetermined amount. In addition, the electrodes  14   a ,  14   b , and  14   c  may be located vertically, or may be located horizontally. Furthermore, it is also good to have the structure that the oscillation circuit  15  is connected to the second electrode  14   b , and the first electrode  14   a  is connected to GND potential. 
     The electrodes  14   a ,  14   b , and  14   c  located as shown in  FIG. 2  constitute capacitance C 1  constituted of the electrode  14   a  and electrode  14   c , and capacitance C 2  constituted of the electrode  14   b  and electrode  14   c , which are connected in series to the oscillation circuit  15 . An oscillation frequency of the output signal S 1  which the oscillation circuit  15  outputs is determined by the series capacitance CX of the capacitance C 1  and capacitance C 2  which are mentioned above. 
       FIG. 3  is a block diagram showing one configuration example of the oscillation circuit shown in  FIG. 2 . 
     The oscillation circuit  15  consists of a ring oscillator constituted of connecting odd stages (three stages in  FIG. 3 ) of inverters  15   a ,  15   b , and  15   c  in series. An inverter  15   d  connected to the inverter  15   c  of the last stage of the ring oscillator is a buffer for transmitting the signal S 1  to the following stage of judgment circuit  16 . Then, when the driving capability of inverters which constitute a ring oscillator is large, it is not necessary to always provide this inverter. 
       FIG. 4  is a block diagram showing one configuration example of the judgment circuit shown in  FIG. 2 . 
     The signal S 1  from the oscillation circuit  15  is inputted into a clock terminal of an n-bit counter  16   a , and its output (B 0  to Bn− 1 ) is inputted into an n-bit comparator  16   b . The n-bit comparator  16   b  inputs an n-bit signal (A 0  to An− 1 ), used as a criterion, besides the output from the n-bit counter  16   a , and outputs a high level when respective bits of the signal (A 0  to An− 1 ) and signal (B 0  to Bn− 1 ) are equal. The output from the n-bit comparator  16   b  is inputted into a clock terminal of a D flip-flop (DFF)  16   c . A D terminal of the DFF  16   c  is connected to a first power supply vdd becoming a high-level of logic. A control signal S 0  from the control section (not shown) of the printer body is inputted into a reset terminal of the n-bit counter  16   a , and a reset terminal of the DFF  16   c.    
       FIG. 5  is a block diagram showing one configuration example of a one-time ROM shown in  FIG. 2 . 
     One-time ROM  17  used in this embodiment is Zener zap type memory which uses a Zener diode ZD. An anode of the Zener diode ZD is connected to the GND potential, and a first resistance R 1 , a source of a first n-type transistor T 1 , and an input terminal of a first inverter INV 1  are connected to a cathode of the Zener diode ZD. Another end of the first resistance R 1  is connected to the first power supply vdd becoming the high level of logic. A drain of the first transistor T 1  is connected to a second power supply VH necessary for writing information. A voltage of the second power supply VH is higher than the voltage of the first power supply vdd, and higher than a peak inverse voltage of the Zener diode ZD. A second resistor R 2  and a drain of the second transistor T 2  are connected to a gate of the first transistor T 1 . Another end of the second resistor R 2  is connected to the power supply VH, and a source of the second transistor T 2  is connected to the GND potential. An output of a second inverter INV 2  is inputted into a gate of the second transistor T 2 . 
     The one-time ROM  17  constituted in this way outputs to the printer body an output signal which varies depending on whether ink zero information is stored in the one-time ROM  17 , when an output of the judgment circuit  16  is inputted into the second inverter INV 2 . The detail of the operation will be described later. 
     It is conceivable to use, for example, flash memory or EEROM as nonvolatile memory for storing the presence of the residual ink amount in an ink tank. However, circuit structure becomes large more than needed when the flash memory or EEROM is used in spite of that memory capacity (number of bits) is at least 1 bit, and special production process is required. Hence, there is a possibility of leading to the cost increase of the print head  13 . In this respect, the above-described memory configuration using the one-time ROM  17  is preferable. 
     In addition, the one-time ROM  17  can be also constituted of fuse memory which consists of polysilicon, in stead of the memory with the Zener zap type structure of being equipped with a Zener diode as described above. Since it is also possible to constitute such fuse memory on a silicon substrate of the print head  13  using semiconductor manufacturing process, it is rare to lead to the cost increase of the print head  13 , eventually the head cartridge  11 . 
     Next, the operation of the head cartridge  11  of this embodiment mentioned above will be explained with reference to  FIGS. 2 to 6A  and  6 B.  FIGS. 6A and 6B  are the operation timing charts of the judgment circuit shown in  FIG. 4 . 
     In order to detect the presence of the residual ink amount in the ink tank  12 , the reset signal S 0  outputted from the control section of the printer body is first made a low level, and the n-bit counter  16   a  and DFF  16   c  of the judgment circuit  16  are made operable. Then, when the signal S 1  is outputted to the judgment circuit  16  from the oscillation circuit  15 , the n-bit counter  16   a  starts counting. When the counter value of the n bit counter  16   a  does not reach a predetermined counter value (value which A 0  to An− 1  express) in the predetermined period whose signal S 0  is a low level (refer to  FIG. 6A ), the output of the n-bit comparator  16   b  does not vary with a low level. Hence, the output of the DFF  16   c  which is the following stage does not vary also from the low level. On the other hand, when the counter value of the n-bit counter  16   a  reaches the predetermined counter value (value which A 0  to An− 1  express) (referring to  FIG. 6B ), the n-bit comparator  16   b  outputs a high level. Hence, an output of the DFF  16   c  which is the following stage becomes a high level. 
     A dielectric constant between each of the electrodes  14   a  and  14   b , and electrode  14   c  varies according to whether ink exists in the gap d between the electrodes  14   a  and  14   b , and electrode  14   c . Thus, the series capacitance CX at the time when there is no ink in the gap d is less than the series capacitance CX at the time when ink is in the gap d. Therefore, when ink is in the gap d, the signal S 1  at a comparatively low frequency is outputted from the oscillation circuit  15 . At this time, the counter value of the n-bit counter  16   a  does not exceed the predetermined counter value in a predetermined period when the signal S 0  is the low level. Hence, the output of the DFF  16   c  does not vary also from the low level. 
     On the contrary, when there is no ink in the gap d, the signal S 1  at a comparatively high frequency is outputted from the oscillation circuit  15 . At this time, the counter value of the n-bit counter  16   a  exceeds the predetermined counter value in the predetermined period when the signal S 0  is the low level. Therefore, the output of the DFF  16   c  becomes a high level. When the output of the DFF  16   c  which is an output of the judgment circuit  16  becomes the high level, the information (ink zero information) that the residual ink amount in the ink tank  12  is zero is recorded in the one-time ROM  17 . 
     Here, with reference to  FIG. 5  mainly, the operation of recording ink zero information in the one-time ROM  17  will be explained. 
     The case that there is residual ink amount in the ink tank  12  and ink exists in the gap d between the electrodes  14   a  and  14   b , and electrode  14   c  will be described. Since the signal outputted from the judgment circuit  16  becomes the low level as mentioned above, the input into the gate of the transistor T 2  becomes the high level, and the transistor T 1  is turned off. Hence, the electric potential of an anode terminal of the Zener diode ZD becomes the same electric potential as the power supply vdd, and the output signal of the one-time ROM  17  becomes the low level. 
     On the other hand, the case that there is no residual ink amount in the ink tank  12  and ink does not exist in the gap d between the electrodes  14   a  and  14   b , and electrode  14   c  will be described. Since the signal outputted from the judgment circuit  16  becomes the high level as mentioned above, the input into the gate of the transistor T 2  becomes the low level, and the transistor T 1  is turned on. When the transistor T 1  is turned on, the electric potential of the anode terminal of the Zener diode ZD is pulled up to the electric potential of the power supply VH. The electric potential of the power supply VH is set to be higher than a peak inverse voltage of the Zener diode ZD. Hence, when being pulled up to the electric potential of the power supply VH, the electric potential of the anode terminal of the Zener diode ZD exceeds the peak inverse voltage of the Zener diode ZD, and hence, a large current flows a PN junction region of the Zener diode ZD. Then, the energy equal to the product of the voltage and current at this time becomes Joule&#39;s heat, aluminum in a PN junction region is fused by the heat, and the PN junction region becomes conductive. As a result, regardless of the state of the output signal from the judgment circuit  16 , the input signal to the inverter INV 1  of the one-time ROM  17  is always set in the low level, and the output signal of the one-time ROM  17  always becomes the high level. 
     That is, when the residual ink amount in the ink tank  12  becomes zero, a high-level output signal is being always outputted from the one-time ROM  17 . In this way, the ink zero information is recorded on the one-time ROM  17 . Therefore, only by the control section of the printer body determining whether the output signal from the one-time ROM  17  is the high level, the control section of the printer body can detect that the residual ink amount in the ink tank  12  became zero. 
     According to the structure of this embodiment, similarly to the first embodiment, the electrodes  14   a ,  14   b , and  14   c  as a sensor, oscillation circuit  15 , judgment circuit  16 , and one-time ROM  17  which constitute a circuit closed within the head cartridge  11  can detect the residual ink amount in the ink tank  2 . As mentioned above, these oscillation circuit  15 , judgment circuit  16 , and one-time ROM  17  can be constituted on a silicon substrate of the print head  13  using the semiconductor manufacturing process. Hence, it is possible to reduce manufacturing cost in comparison with the case that they are constituted separately on a circuit board of the printer body. In addition, according to the structure of this embodiment, it is possible to detect residual ink amount without performing the processing using a CPU of a host computer or a printer body. Hence, since the residual ink amount is detectable so long as only the printer body is started, it is possible to increase convenience for a user. 
     Furthermore, in this embodiment, since the head cartridge  11  in itself is equipped with the one-time ROM  17  as non-volatile memory, ink zero information is stored in the one-time ROM  17  when the ink in the ink tank  12  becomes empty. Hence, even if the head cartridge  11  was removed from the printer body once and is mounted in the printer body again, the ink zero information is stored in the one-time ROM  17  as it is. By reading this ink zero information by the control section of the printer body in which the head cartridge  11  is mounted (specifically, by determining whether the output from the one-time ROM  17  is the high level), it is detectable whether the ink tank  12  of the head unit  11  which is newly mounted in the printer body is empty. Therefore, according to this embodiment, residual ink amount can be detected promptly without performing the sequence for residual ink amount detection after a head cartridge is newly mounted in the printer body. Hence, it is possible promptly to inform a user of that there is no residual ink amount, and further, it is possible to shorten recording operation time of the printer by the time which sequence operation needs. 
     In addition, in the structure of the first embodiment shown in  FIG. 1 , in order to let the wiring, which connects the sensor  4  provided in the ink tank  2 , and the detection circuit  5  outside the ink tank  2 , pass, it is necessary to form a through hole in the wall section of the ink tank  2 . In this case, in order to prevent ink from leaking from the through hole, it is necessary to take a measure of plugging up the through hole appropriately after letting the wiring pass the through hole. On the other hand, in the structure of this embodiment, the wiring connected to the electrodes  14   a  and  14   b  embedded in the wall section of the ink tank  12  does not penetrate the wall section of the ink tank  12 . Hence, since there is no possibility of the ink in the ink tank  12  leaking even if the hole for letting the wiring pass is not plugged up, it is not necessary to take the measure of plugging up the hole. Therefore, it is possible to reduce the production man-hours of the ink tank  12  by labor hours of taking the measure of plugging up the hole, and further, to attain the manufacturing cost reduction of the ink tank  12 . 
     Other Embodiments 
     A liquid discharge head (print head) is producible by forming a heat-generating resistor with a heat-generating resistor layer formed on an insulating layer of the semiconductor substrate of the print head of each embodiment mentioned above, and combining discharge opening forming members, such as molding resin and a top board consisting of a film, so as to form a discharge opening and a liquid path communicating therewith. Then, by constituting a head cartridge by connecting a liquid container (ink tank) to such the liquid discharge head, mounting this in a printer body, and supplying power supply potential form a power supply circuit of the printer body, and image data from an image processing circuit of the printer body to the liquid discharge head, the printer body and head cartridge mounted therein operate as an ink jet printer. 
       FIG. 7  is a drawing for explaining a discharge unit in one embodiment of a liquid discharge cartridge of the present invention, and shows the discharge unit in the state that its part is cut. 
     Electrothermal conversion elements  141  which generate heat by receiving an electric signal to flow a current, and making ink discharged from discharge openings  153  with bubbles generated by the heat are arranged in two or more rows on an element substrate  152  which is a semiconductor substrate where the circuits shown in the explanation of the above-mentioned each embodiment are produced. A wiring electrode  154  which supplies an electric signal for driving each electrothermal conversion element,  141  is provided in each of these electrothermal conversion elements  141 . 
     A flow path  155  for supplying ink to each discharge opening  153  provided in a position opposite to each electrothermal converting element  141  is provided corresponding to each discharge opening  153 . These discharge openings  153  and a wall constituting the flow paths  155  are provided in a grooved member  156 . The flow paths  155  and a common liquid chamber  157  for supplying ink to a plurality of flow paths  155  are provided by connecting this grooved member  156  to the above-mentioned element substrate  152 . 
       FIG. 8  is a perspective view showing the structure of the liquid discharge head where the discharge unit shown in  FIG. 7  is incorporated. 
     As shown in  FIG. 8 , a discharge unit  150  is built in a shell body  158 . As mentioned above, the discharge unit  150  is constituted by the member  156  being mounted on the device substrate  152 , the member  156  which constitutes the discharge openings  153  and flow paths  155 . A flexible, printed wiring board  160  on which contact pads,  159  for receiving electric signals from the printer body are provided is connected to the discharge unit  150 , and the electric signals used as various drive signals are supplied to the discharge unit  150  through the flexible printed wiring board  160  from the control section of the printer body. 
       FIG. 9  is a perspective view showing the schematic configuration of an inkjet recording apparatus IJRA which is one embodiment of a liquid discharge apparatus to which a liquid discharge cartridge according to the present invention is applied. 
     A carriage HC which has a pin (not shown) engaged with a helical groove  5004  of a lead screw  5005  which is interlocked with the normal and reverse rotation of a drive motor  9011 , and is rotated through driving force transmission gears  5011 , and  5009  is reciprocated along with a guide shaft  5003  in the directions of arrows a and b in connection with the normal and reverse rotation of the lead screw  5005 . A head cartridge including a recording head IJC and an ink tank IT which supplies ink to this is mounted in the carriage HC. 
     A paper pressure plate  5002  presses recording paper P to a platen (not shown), which is recording medium conveying means, over a moving range of the carriage HC. A photo-coupler  5007  and  5008  as home position detecting means confirms the presence of a lever  5006  of the carriage HC in this range, and outputs a signal for switching the rotary direction of the drive motor  9011  or the like. A cap member  5022  which caps an ink ejection orifice formation face of the recording head IJC is supported by a supporting member  5013 . When the suction of suction recovery is started, the lever  5012  moves with the movement of a cam  5020  engaging with the carriage HC, the driving force from the drive motor  9011  is switched by publicly-known transmission means such as clutch switching, and movement control is made so that the cap member  5022  may contact the ink ejection orifice formation face of the recording head IJC. By sucking the cap member  5022  by suction means (not shown) in this state, the suction recovery of the recording head IJC is performed through the opening  5023  in a cap. 
     The moving member  5019  which makes it possible to move a cleaning blade  5017  in the direction that the cleaning blade  5017  is brought close to or is separated from the recording head IJC is supported by a body supporting plate  5018 , and the cleaning blade  5017  is provided in the moving member  5019 . In addition, as for the cleaning blade  5017 , it is needless to say that not only the shown form but also other widely known forms are applicable to this embodiment. 
     The ink jet recording apparatus IJRA is constituted so that the desired operation out of capping operation, cleaning operation, and suction recovery operation may be performed in each corresponding position, by making the lead screw  5005  perform predetermined rotation when the carriage HC moves to a home position region. The timing of performing these operations is well-known, and such widely known timing is also applicable to this embodiment. The above-mentioned each structure is excellent independently or complexly, and is a preferable configuration example to which the liquid discharge head in the present invention is applied. 
     In addition, this apparatus IJRA has an electrical circuit for supplying a supply voltage, an image signal, a drive control signal, and the like to the discharge unit  150  (refer to  FIG. 7  and the like). 
     Furthermore, it is apparent that the present invention is not limited to the various embodiments mentioned above, and that it is possible to substitute an alternative or an equivalent for each component of the present invention so long as it can solve the subjects mentioned above. 
     This application claims-priority from Japanese Patent Application No. 2004-115339 filed on Apr. 9, 2004, which is hereby incorporated by reference herein.