JP4532890B2 - Recording head and recording apparatus provided with the recording head - Google Patents

Description

  The present invention relates to a recording head and a recording apparatus including the recording head, and more particularly to a recording head capable of equalizing the driving conditions of a plurality of recording elements connected to a common power source and a recording apparatus including the recording head. Is.

  For example, as an information output device in a word processor, personal computer, facsimile, or the like, there is a printer that records information such as desired characters and images on a sheet-like recording medium such as paper or film.

  Various types of recording methods are known for printers, but inkjet methods have recently been used for reasons such as non-contact recording on recording media such as paper, easy colorization, and high quietness. It has attracted particular attention, and as its configuration, a serial head that performs recording while mounting a recording head that ejects ink according to desired recording information and reciprocating scanning in a direction perpendicular to the feeding direction of a recording medium such as paper In general, the recording method is widely used because it is inexpensive and easy to downsize.

  In particular, the thermal ink jet method that uses the ink bubbling phenomenon induced by the thermal energy generated by energizing the heater in contact with the ink for several microseconds to eject ink droplets has a high density of nozzles on the recording head. Can be formed. The fact that a large number of nozzles can be formed in the recording head is particularly noticeable because it is effective in terms of improving the recording speed.

  Such a thermal ink jet recording head (hereinafter referred to as a recording head) includes a heater for heating ink on a silicon single crystal substrate or the like by a semiconductor integrated circuit process, a protective film for the heater, and a driver circuit for supplying current to the heater. A recording element substrate (hereinafter referred to as a heater board) integrally formed with a logic circuit for performing the control is used.

  Hereinafter, an example of control used for a heater board of a conventional recording head will be described.

  FIG. 7 is a block diagram showing a schematic configuration of a conventional heater board circuit. The arrows in the figure schematically show the flow of logic signals for controlling the recording operation.

  As shown in FIG. 7, an ink supply port 102 for introducing ink to each nozzle of the recording head is formed in the center of the silicon substrate 101 by etching or the like. Further, two heater arrays 103 each having a plurality of heaters are disposed adjacent to the ink supply port 102 so as to face each other.

  A plurality of logic signals corresponding to the power supply voltage and recording information are supplied to the input terminal 109 from the recording apparatus main body. Here, the input logic signal is input to the logic circuit 107 through the input circuit 108 arranged for the purpose of ESD protection and input waveform shaping.

  The logic circuit 107 is provided with a shift register, a decoder, and the like, and appropriately performs parallel-serial conversion, decoding, logic operation, and the like on the input signal. An output signal from the logic circuit 107 is sent to another logic circuit 106.

  The logic circuit 106 has the same number of logic signal outputs as the heaters so that the plurality of heaters arranged in the heater array 103 can be individually driven and controlled based on the signal from the logic circuit 107.

  The logic signal output from the logic circuit 106 is sent to the level conversion circuit array 105 arranged corresponding to the heater array 103. Here, the level of the logic signal is converted to a higher voltage amplitude.

  Normally, a logic circuit operates using a low voltage of about 5V or 3.3V, but to drive a power transistor that supplies current to the heater, drive at a high voltage of 7V to 15V or higher. Since the efficiency is improved by the control, this level conversion is performed. Then, the signal from the level conversion circuit array 105 is sent to the power transistor array 104, and the selected power transistor is driven.

  As described above, among the output signals from the logic circuit 106, only the heater corresponding to the activated logic signal is energized, the ink is foamed, the ink is ejected from the corresponding nozzle, and the recording operation is performed.

  FIG. 8 is a circuit diagram in which a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater are extracted from the circuit shown in FIG.

In FIG. 8, the logic circuit 106-1 shows only the output part of the logic circuit 106. Here, the power supply voltage of the logic circuit is VDD, and its value is 3.3V or 5V. The level conversion circuit 105-1 is a circuit for level-converting the output signal from the logic circuit 106-1 to a higher voltage VHT, and the value of VHT is about 7 to 15V. The power transistor 104-1 functions as a switch for inputting and outputting the output signal from the level conversion circuit 105-1 to its gate. The heater 103-1 is an electrothermal converter that generates heat when energized, and overheats and foams ink that is in contact via a protective film or the like. Here, the value of the power supply voltage VH for passing a current through the heater is about 10 to 30V.
Japanese Patent Laid-Open No. 10-034898 JP-A-11-129479

  As is apparent from the circuit configuration, when the logic power supply voltage VDD is opened, the result of the logic operation becomes indefinite. Here, when the drive power supply voltage VHT of the power transistor and the heater drive power supply voltage VH are applied, an abnormal current may flow in the heater power supply voltage because the result of the logical operation is indefinite.

  This abnormal current may continue to flow for an indefinite period of time for the logic circuit, which is a serious problem because it may cause damage to the heater.

  When a power supply voltage is applied from the recording apparatus main body to the recording head so that such destruction does not occur, for example, after the logic power supply voltage VDD is first applied to determine the logic, the power transistor drive power supply voltage VHT is applied. In addition, it is necessary to take a power-on sequence at different timings such as applying the heater drive power supply voltage VH.

  Similarly, when the power supply is cut off, it is necessary to first cut off the application of the power transistor drive power supply voltage VHT after first cutting off the application of the heater drive power supply voltage VH, and finally cut off the application of the logic power supply voltage VDD. there were.

  However, realizing such a power-on / off sequence complicates the power supply circuit on the recording apparatus main body side, and as a result, there is a problem in that the production cost of the apparatus increases. .

  The present invention has been made in view of the above conventional example, and an object of the present invention is to provide a recording head having a simple configuration that does not need to be aware of the power-on / off sequence, and a recording apparatus including the recording head.

  In order to achieve the above object, the recording head of the present invention has the following configuration.

That has a plurality of printing elements, and driving elements for driving the recording elements according to the input signal having the amplitude of the first voltage, a recording head for controlling the driving of the drive element, the input signal A first logic circuit having a shift register and a decoder for processing the signal, and a control signal for individually controlling driving of the plurality of recording elements based on a signal output from the first logic circuit. and second logic circuit, a control signal having a signal amplitude of the second said output from the logic circuit of the first voltage the first voltage is greater than the second voltage signal amplitude of the control signal having an amplitude of boosting and a step-up circuit for outputting to the driving element, the second logic circuit is characterized in that it has a pull-down resistors for pulling down the ground voltage side power line of the first voltage .

  The booster circuit is preferably configured to operate as an inverter.

  As a detailed configuration of the booster circuit, the booster circuit is formed of a first nMOS transistor that inputs the control signal to a gate, a load connected in series between the drain of the first nMOS transistor and the second voltage. A first inverter circuit; and a second inverter circuit composed of a second nMOS transistor and a first pMOS transistor, and an output of the first inverter circuit is an input of the second inverter circuit The output of the second inverter circuit is preferably input to the drive element as a drive signal.

  The specific configuration of the load may be (1) a resistor, or (2) a second pMOS transistor that gate-inputs the control signal in common with the first nMOS transistor. (3) A plurality of pMOS transistors connected in series, and the control signal may be input to any one of the plurality of pMOS transistors.

  The recording head is preferably an ink jet recording head that performs recording by ejecting ink from each recording element. In that case, thermal energy applied to the ink in order to eject ink using thermal energy. It is desirable that each recording element is provided with an electrothermal transducer for generating the above.

  According to another aspect of the invention, a recording apparatus that performs recording with the recording head having the above-described configuration is provided.

  Therefore, according to the present invention, even if the signal line for inputting the signal having the amplitude of the first voltage is open, the voltage is fixed to 0 V by the pull-down resistor, so that the control signal is generated according to the input signal. Since the output from the drive control circuit is also 0V, it is possible to prevent the drive element from being erroneously driven by the control signal.

  Accordingly, there is an advantage that the recording element does not malfunction and the recording head is protected from damage.

  On the other hand, the recording apparatus equipped with this recording head does not need to consider the power-on sequence in consideration of whether or not the signal line for inputting the signal is open in order to operate the recording head. The configuration of the power supply circuit to the recording head provided can be simplified, which contributes to the reduction of the production cost of the recording apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) is not only for forming significant information such as characters and figures, but also for human beings visually perceived regardless of significance. Regardless of whether or not it has been manifested, it also represents a case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Furthermore, “ink” (sometimes referred to as “liquid”) is to be interpreted broadly in the same way as the definition of “recording (printing)” above. It represents a liquid that can be used for forming a pattern or the like, processing a recording medium, or processing an ink (for example, solidification or insolubilization of a colorant in ink applied to the recording medium).

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

  The “element base” used below does not indicate a simple base made of a silicon semiconductor but a base provided with each element, wiring, and the like. The element substrate may have a plate shape.

  Furthermore, “on the element substrate” not only indicates the element substrate, but also indicates the surface of the element substrate and the inside of the element substrate near the surface. In addition, the term “built-in” in the present invention is not a word indicating that each individual element is simply placed on the substrate, but each element is integrated on the element substrate by a semiconductor circuit manufacturing process or the like. It shows that it is formed and manufactured.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus 1 which is a typical embodiment of the present invention.

  As shown in FIG. 1, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) transmits a driving force generated by a carriage motor M1 to a carriage 2 on which a recording head 3 that performs recording by discharging ink according to an ink jet system is mounted. 4, the carriage 2 is reciprocated in the direction of arrow A, and for example, a recording medium P such as recording paper is fed through a paper feeding mechanism 5 and conveyed to a recording position. Recording is performed by ejecting ink onto the recording medium P.

  Further, in order to maintain the state of the recording head 3 satisfactorily, the carriage 2 is moved to the position of the recovery device 10 and the ejection recovery process of the recording head 3 is intermittently performed.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus 1, an ink cartridge 6 for storing ink to be supplied to the recording head 3 is mounted. The ink cartridge 6 is detachable from the carriage 2.

  The recording apparatus 1 shown in FIG. 1 can perform color recording. For this reason, the carriage 2 contains four inks containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. An ink cartridge is installed. These four ink cartridges are detachable independently.

  Now, the carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 applies energy according to a recording signal to selectively eject ink from a plurality of ejection ports for recording. In particular, the recording head 3 of this embodiment employs an ink jet system that ejects ink using thermal energy, and responds by applying a pulse voltage to a corresponding electrothermal transducer in accordance with a recording signal. Ink is ejected from the ejection port.

  Further, in FIG. 1, reference numeral 14 denotes a transport roller that is driven by a transport motor M2 to transport the recording medium P.

<Control Configuration of Inkjet Recording Apparatus (FIG. 2)>
FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the controller 600 includes an MPU 601, a program corresponding to a control sequence to be described later, a required table, a ROM 602 that stores other fixed data, a carriage motor M1, a conveyance motor M2, and a recording. A special purpose integrated circuit (ASIC) 603 that generates a control signal for controlling the head 3, and a RAM 604, an MPU 601, an ASIC 603, and a RAM 604, which are provided with image data development areas and program execution areas, are connected to each other. A system bus 605 for transferring data, and an A / D converter 606 for inputting analog signals from the sensor group described below, A / D converting them, and supplying digital signals to the MPU 601 and the like.

  In FIG. 2, reference numeral 610 denotes a computer (or a reader for image reading, a digital camera, etc.) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host apparatus 610 and the recording apparatus 1 via an interface (I / F) 611.

  Further, reference numeral 620 denotes a switch group, which instructs activation of a power switch 621, a print switch 622 for instructing printing start, and a process (recovery process) for maintaining the ink ejection performance of the recording head 3 in a good state. For example, a recovery switch 623 for receiving a command input from the operator. Reference numeral 630 denotes a position sensor 631 such as a photocoupler for detecting the home position h, a temperature sensor 632 provided at an appropriate location of the recording apparatus for detecting the environmental temperature, and the like. It is a sensor group.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 2 in the direction of arrow A, and 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  The ASIC 603 transfers drive data (DATA) of the recording element (heater) to the recording head while directly accessing the storage area of the RAM 602 during recording scanning by the recording head 3.

<Structure of ink flow path and ink discharge port of recording head (FIG. 9)>
FIG. 9 is a perspective view showing a three-dimensional structure of a portion of the recording head 3 that ejects black ink.

  From FIG. 9, the flow of ink supplied from the ink cartridge 6K containing black (K) ink becomes clear. As shown in FIG. 9, the recording head 3 has an ink supply channel 1102 for supplying black (K) ink. From the ink cartridge 6K, black ink is supplied to the ink supply channel 102 from the back side of the substrate 1100. A supply path (not shown) for supplying is provided.

  Through this ink channel, the black ink is guided to the electrothermal transducer (heater) 40 provided on the substrate by the ink flow path 30. When the electrothermal transducer (heater) 40 is energized through a circuit to be described later, heat is applied to the ink on the electrothermal transducer (heater) 40 and the ink is boiled. Ink droplets 90 are ejected from the ejection port 35 by the bubbles.

  In FIG. 9, reference numeral 1100 denotes an electrothermal transducer to be described in detail later, various circuits for driving the memory, memory, various pads serving as electrical contacts with the carriage 2, and recording on which various signal lines are formed. A head substrate (hereinafter referred to as a head substrate or a heater board).

  One electrothermal transducer (heater), a MOS-FET for driving the electrothermal transducer, and the electrothermal transducer (heater) are collectively referred to as a recording element, and a plurality of recording elements are collectively referred to as a recording element section.

  Although FIG. 9 shows a three-dimensional structure corresponding to the portion for ejecting black ink in the recording head 3, the corresponding portion of the recording head 3 used for ejecting the other three color inks also has the same structure. is doing. However, the structure is three times that shown in FIG. That is, there are three ink channels, and the size of the head substrate is about three times as large.

<Configuration of head cartridge (FIG. 10)>
As described above, the ink cartridge and the recording head may be formed so as to be separable and replaceable. However, as the head cartridge in which the ink cartridge and the recording head are integrally configured, the ink is used up. Sometimes the entire head cartridge may be replaced.

  FIG. 10 is an external perspective view showing a configuration of a head cartridge IJC in which an ink cartridge and a recording head are integrated. In the head cartridge IJC, as shown in FIG. 10, the left side from the dotted line K is the ink cartridge part IT, and the right side is the recording head part IJH. Such a head cartridge IJC is provided with an electrode (not shown) for receiving an electric signal supplied from the carriage side when mounted on the carriage, and the recording head is driven by this electric signal. Ink is discharged.

  In FIG. 10, reference numeral 500 denotes an ink discharge port array. Further, the ink cartridge portion IT is provided with a fibrous or porous ink absorber for holding ink, and is filled with ink.

  Hereinafter, embodiments of the recording head according to the present invention mounted on the above-described ink jet recording apparatus will be described.

  The overall configuration of the heater board mounted on the recording head 3 according to the present invention is as shown in FIG. 7, but the detailed configuration will be described in the following embodiments. Has a characteristic structure. In the description, attention is paid to a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater among a plurality of heaters provided in the heater board.

[First embodiment]
FIG. 3 is an equivalent circuit diagram excerpting a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater built on the element base of the recording head according to the first embodiment of the present invention. It is. In FIG. 3, the same components as those already described with reference to FIGS. 7 to 8 are denoted by the same reference numerals, and the description thereof is omitted.

  Here, the value of the power supply voltage VDD of the logic circuit is 3.3 V or 5 V as in the conventional example, and the value of the output signal voltage VHT from the level conversion circuit 105-1 is about 7 to 15 V as in the conventional example. In addition, the value of the heater power supply voltage VH is about 10 to 30 V as in the conventional example.

  The circuit shown in FIG. 3 is provided with a pull-down resistor 106-2, and this pull-down resistor is used to determine the voltage as the substrate voltage when the power supply voltage VDD of the logic circuit is indefinite. It is a resistance of several tens to several hundreds kΩ.

  In this embodiment, the signal transmitted from the output unit 106-1 of the logic circuit to the level conversion circuit 105-1 is only the signal from the node 306, and is transmitted from the level conversion circuit to the power transistor 104-1. The signal is only the signal from the node 307.

  When the power supply voltage VDD of the logic circuit is opened, the signal from the node 306 is fixed to 0 (zero) V by the pull-down resistor 305, so that the output is almost 0 V. In this state, when the power transistor drive power supply voltage VHT and the heater drive power supply voltage VH are applied, since the input signal from the node 306 is almost 0 (zero) V in the level conversion circuit, the output signal at the node 307 is 0 (zero) V. Therefore, the power transistor 104-1 is turned off and the heater 103-1 is not energized.

  Therefore, according to the embodiment described above, even if the power supply voltage VDD of the logic circuit is open, the heater is energized and does not malfunction.

[Second Embodiment]
FIG. 4 is an equivalent circuit diagram excerpting a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater built on the element base of the recording head according to the second embodiment of the present invention. It is. In FIG. 4, the same components as those already described with reference to FIGS. 3 and 7 to 8 are denoted by the same reference numerals, and the description thereof is omitted.

  Here, the value of the power supply voltage VDD of the logic circuit, the value of the output signal voltage VHT from the level conversion circuit 105-1, and the value of the heater power supply voltage VH are the same as those in the conventional example and the first embodiment.

  When the configuration shown in this embodiment is compared with the first embodiment, in the first embodiment, three MOS transistors having the same polarity are connected in series on the output unit 106-1 side of the logic circuit in the level conversion circuit 105-1. (Region surrounded by a one-dot chain line in FIG. 3) is used, but this portion is configured to be replaced with a load resistor 308 in this embodiment.

  In this embodiment, the load resistor 308 may be replaced with, for example, a pMOS transistor.

  FIG. 5 is a circuit diagram in which a logic circuit for driving one heater, a level conversion circuit, a power transistor, and the heater are extracted as a modification of the second embodiment.

  As can be seen from a comparison between FIG. 4 and FIG. 5, the load resistor 308 is replaced with a pMOS transistor 309. Since the output signal from the node 306 of the output unit 106-1 of the logic circuit is applied to the gate of the pMOS transistor 309, a voltage higher than the power supply voltage VDD of the logic circuit is not applied. When the potential difference between the power transistor drive power supply voltage VHT and the power supply voltage VDD of the logic circuit is higher than the threshold value of the pMOS transistor 309, the pMOS transistor 309 does not turn off and functions as a resistive load. Become. Therefore, the operation is the same as that of the circuit having the resistance load 308 shown in FIG.

  Note that the pMOS transistor 309 is functionally arranged as a resistance element and is shown as one pMOS transistor in FIG. 5, but actually, for example, as shown in FIG. 3 of the first embodiment. As described above, a plurality of pMOS transistors having the same size or different sizes may be arranged in series. Furthermore, a plurality of or one pMOS transistor and one resistor may be mixed as a load.

  Now, since the power supply voltage VDD is fixed to 0 (zero) V by the pull-down resistor 106-2 when the power supply voltage VDD of the logic circuit is opened, the signal from the node 306 is almost equal to the output voltage. 0 (zero) V. In this state, when the power transistor drive power supply voltage VHT and the heater drive power supply voltage VH are applied, since the input signal from the node 306 is almost 0 (zero) V in the level conversion circuit, the output signal at the node 307 is 0 (zero) V. Therefore, the power transistor 104-1 is turned off and the heater 103-1 is not energized.

  Therefore, according to the embodiment described above, even if the power supply voltage VDD of the logic circuit is open, the heater is energized and does not malfunction.

[Third embodiment]
FIG. 6 is an equivalent circuit diagram excerpted from a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater built on the element substrate of the recording head according to the third embodiment of the present invention. It is. In FIG. 6, the same components as those already described with reference to FIGS. 3 and 7 to 8 are denoted by the same reference numerals, and the description thereof is omitted.

  Here, the value of the power supply voltage VDD of the logic circuit, the value of the output signal voltage VHT from the level conversion circuit 105-1, and the value of the heater power supply voltage VH are the same as those in the conventional example and the first embodiment.

  In this embodiment, the gate 609 of the nMOS transistor 608 of the level conversion circuit 105-1 is supplied from a bias circuit (not shown) to a voltage not higher than the power supply voltage VDD of the logic circuit and not lower than the threshold voltage (Vth) of the nMOS transistor 608. (Vbias) is applied.

  When the output voltage from the node 306 of the output unit 106-1 of the logic circuit is 0 (zero) V, the voltage between the gate and the source of the nMOS transistor 608 is not more than the power supply voltage VDD of the logic circuit and not less than the threshold voltage. The voltage is applied as it is, and the nMOS transistor 608 is turned on. Therefore, the nMOS transistor 608 always operates as a resistor having an ON resistance.

  Therefore, a current flows from the power transistor drive power supply voltage VHT application side to the ground voltage VSS side via the source / drain of each of the pMOS transistor 611, the nMOS transistor 608, and the nMOS transistor 613. Further, the nMOS transistor 610 is in an off state because its gate potential is 0 (zero) V.

  On the other hand, since the pMOS transistor 612 forms a current mirror circuit with the pMOS transistor 611 through which a current flows, the pMOS transistor 612 is turned on. Therefore, the voltage at the node 614 becomes the power transistor drive power supply voltage VHT, and the voltage at the gate 307 of the power transistor 604 connected via the inverter becomes 0 (zero) V. Accordingly, when the logic circuit signal is 0 (zero) V, no current flows through the heater 103-1.

On the other hand, when the output voltage from the node 306 of the output unit 106-1 of the logic circuit is the power supply voltage VDD of the logic circuit, the gate-source voltage (V _GS ) of the nMOS transistor 608 is (Vbias−VDD). Here, since the bias voltage (Vbias) is set to a voltage equal to or higher than the threshold voltage (Vth) of the nMOS transistor 608 and lower than the power supply voltage VDD of the logic circuit, V _GS ≦ 0 (zero) V. Therefore, the nMOS transistor 608 is turned off and no current flows through the pMOS transistor 611. Therefore, the pMOS transistor 611 that does not flow current and the pMOS transistor 612 that forms a current mirror are also turned off.

  Here, since the nMOS transistor 610 to which the output signal from the node 306 is connected to the gate is turned on, the signal voltage at the node 614 becomes 0 (zero) V. Therefore, the gate potential 607 of the power transistor 604 connected from the node 614 via the inverter becomes the power transistor drive power supply voltage VHT, the power transistor 104-1 is turned on, and a current flows through the heater 103-1.

  Now, since the power supply voltage VDD is fixed to 0 (zero) V by the pull-down resistor 106-2 when the power supply voltage VDD of the logic circuit is opened, the signal from the node 306 is almost equal to the output voltage. 0 (zero) V. In this state, when the power transistor drive power supply voltage VHT and the heater drive power supply voltage VH are applied, since the input signal from the node 306 is almost 0 (zero) V in the level conversion circuit, the output signal at the node 307 is 0 (zero) V. Therefore, the power transistor 104-1 is turned off and the heater 103-1 is not energized.

  Therefore, according to the embodiment described above, even if the power supply voltage VDD of the logic circuit is open, the heater is energized and does not malfunction.

  In the embodiment described above, even if the power supply voltage VDD of the logic circuit is open, the heater is energized and does not malfunction. On the main body side, it is possible to turn on / off the power without being conscious of the power-on sequence or the power-off sequence as in the prior art, and the power supply circuit on the recording apparatus main body side can be simply configured. Thereby, the production cost of the recording apparatus can be reduced.

[Other embodiments]
The embodiment described above is a so-called bubble jet (registered trademark) type ink jet recording head in which ink is rapidly heated and vaporized by a heating element (heater) and ink droplets are ejected from an orifice by the pressure of the generated bubbles. Although described by way of example, it will be apparent that the present invention can be applied to recording heads that perform recording by other methods.

  In this case, instead of the heater resistance in each of the above-described embodiments, elements used in each system are provided.

  In the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiments include means (for example, an electrothermal converter) that generates thermal energy as energy used for ink ejection, particularly in the ink jet recording system, and changes the state of the ink by the thermal energy. High density and high definition of the recording can be achieved by using the generating method.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both a so-called on-demand type and a continuous type. In particular, in the case of the on-demand type, a rapid temperature rise exceeding the film boiling corresponding to the recorded information is applied to the electrothermal transducer disposed corresponding to the liquid path holding the liquid (ink). By applying at least one drive signal that gives the heat, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head, resulting in a one-to-one correspondence to this drive signal. This is effective because bubbles in the liquid (ink) can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. When the drive signal is pulse-shaped, the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve the discharge of the liquid (ink) with particularly excellent responsiveness, which is more preferable.

  Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is satisfied by a combination of a plurality of recording heads as disclosed in the above specification. Either a configuration or a configuration as a single recording head formed integrally may be used.

  In addition, it may be a cartridge type recording head cartridge in which an ink tank (container) is provided integrally with the recording head itself described in the above-described embodiment. It may be a replaceable chip type recording head configuration that allows easy connection and supply of ink from the apparatus main body. The ink tank of the recording head cartridge may be filled or refilled with ink.

1 is an external perspective view showing an outline of a configuration of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a control circuit of the ink jet recording apparatus of FIG. 1. FIG. 3 is an equivalent circuit diagram in which a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater of the recording head according to the first embodiment of the present invention are extracted. FIG. 7 is an equivalent circuit diagram in which a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater of a recording head according to a second embodiment of the present invention are extracted. FIG. 9 is a circuit diagram excerpting a logic circuit, a level conversion circuit, a power transistor, and a heater for driving one heater of a recording head according to a modification of the second embodiment of the present invention. FIG. 7 is an equivalent circuit diagram in which a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater of a recording head according to a third embodiment of the present invention are extracted. It is a block diagram which shows schematic structure of the conventional heater board circuit. FIG. 8 is a circuit diagram in which a logic circuit, a level conversion circuit, a power transistor, and the heater for driving one heater are extracted from the circuit shown in FIG. 7. FIG. 3 is a perspective view showing a three-dimensional structure of a portion of the recording head 3 that ejects black ink. 2 is an external perspective view showing a configuration of a head cartridge IJC in which an ink cartridge and a recording head are integrated. FIG.

Explanation of symbols

3 Recording Head 103-1 Heater 104-1 Power Transistor 105-1 Level Conversion Circuit 106-1 Output Unit 106-2 of Logic Circuit Pull-down Resistor 306, 307 Node 308 Load Resistor 309 pMOS Transistors 608, 610, 613 nMOS Transistor 609 Bias Input 611, 612 pMOS transistor

Claims (9)

Has a plurality of printing elements, and driving elements for driving the recording elements according to the input signal having the amplitude of the first voltage, a recording head for controlling the driving of the drive element,
A first logic circuit having a shift register and a decoder for processing the input signal;
A second logic circuit that outputs a control signal having an amplitude of the first voltage for individually driving and controlling the plurality of recording elements based on a signal output from the first logic circuit;
Boosting the signal amplitude of the control signal having the amplitude of the first voltage output from the second logic circuit to a control signal having a signal amplitude of the second voltage larger than the first voltage, the driving element and a booster circuit for outputting a,
The recording head, wherein the second logic circuit has a pull-down resistor for pulling down the power line of the first voltage to the ground voltage side .   The recording head according to claim 1, wherein the booster circuit has a configuration that operates as an inverter. The booster circuit includes:
A first inverter circuit formed by a first nMOS transistor that gate-inputs the control signal, a load connected in series between the drain of the first nMOS transistor and the second voltage;
A second inverter circuit composed of a second nMOS transistor and a first pMOS transistor;
The output of the first inverter circuit is connected to the input of the second inverter circuit, and the output of the second inverter circuit is input to the drive element as a drive signal. Recording head.   The recording head according to claim 3, wherein the load is a resistor.   4. The recording head according to claim 3, wherein the load is a second pMOS transistor that gate-inputs the control signal in common with the first nMOS transistor. The load is a plurality of pMOS transistors connected in series,
The recording head according to claim 3, wherein the control signal is input to any one gate of the plurality of pMOS transistors. The recording head is a recording head according to any one of claims 1 to 6, characterized in that an ink jet recording head for recording by discharging ink from the recording element. The recording head according to claim 7 , wherein the recording element is an electrothermal transducer that generates thermal energy to be applied to ink in order to eject ink using thermal energy. Recording apparatus for recording by the recording head according to any one of claims 1 to 8.

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