JP2002137398A - Ink-jet recording head and driving method therefor, and ink-jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce ringing and increase the resistance amount of latch up in a current waveform for driving a heater. SOLUTION: A voltage waveform with a time constant is applied in an area with a high gate voltage Vg1→Vg2 in the case the NMOS transistor is changed from on to off and a low reference current, and a steep voltage waveform is applied in an area with a low gate voltage Vg2→Vg3 and a reference current increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet recording head, a method of driving the same, and an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, a heater drive circuit for heating, foaming, and discharging ink in an ink jet printer or the like is configured as shown in FIG. 14 disclosed in Japanese Patent Application Laid-Open No. H11-138775.

In FIG. 14, M1 to M4 are NMOS transistors as switching elements constituting switching means, R1 to R3 are resistors, VH is a terminal to which power is supplied, and IN is a control input terminal. Note that the resistors R1 to R3
May be a structure using polysilicon, but may be a thin film resistor that can be formed on an element substrate.

Next, the circuit operation of FIG. 14 will be briefly described.

When a signal from a low level to a high level is input to the IN terminal, a similar signal is supplied to the gate of the NMOS transistor M1 and the NMOS transistor M1 is turned on and off at substantially the same timing. However, other NMOS transistors M2
To 4 are their own gate capacitances and resistances R1 to R3.
Signal is given to the gate by a certain time due to the RC time constant, and the signal is turned on / off in the order of M2, M3, and M4, so that the current IH flowing through the heater can be stepped, and the ringing Development can be suppressed.

[0006] This makes it possible to suppress deterioration of the heater and the switching means and malfunction due to noise.

[0007]

In a printer or the like that requires high speed and high definition, the density of nozzles for ejecting ink in a recording head and the number of nozzles are increased. In an ink jet recording head in which ink is heated and foamed by a heater and the ink is ejected from a nozzle by the energy, it is necessary to drive more heaters simultaneously at a higher speed. When a heater and a drive circuit are formed on the same substrate as a heater board, it is also important to reduce the area of the heater board and increase the number of heater boards that can be manufactured from the same board material in order to reduce costs. .

Here, the increase in the number of simultaneous ejection nozzles and the reduction in the area of the heater board cause the following problems.

First, if the number of wirings from the power supply to the heater increases due to the increase in the number of simultaneous ejection nozzles, and the area of the wiring region remains unchanged, the wiring resistance per heater increases. In addition, a reduction in chip size is also required due to a demand for cost reduction. As a result, a wiring area from a power supply to a heater is reduced, and as a result, wiring resistance may increase.

Similarly, a reduction in chip size results in a decrease in the transistor area for driving the heater and an increase in the on-resistance of the transistor.

Further, as the number of simultaneous ejection nozzles increases, the amount of current flowing at the same time increases, and the voltage drop at the common wiring portion also increases. Assuming that the power supply voltage and the heater resistance value are constant, the current flowing through the heater decreases due to the voltage drop, and the power supplied to the heater decreases. For this reason, it is necessary to increase the current application time (pulse) to the heater by an amount corresponding to the decrease in the input power. Because of the necessity, it is difficult to increase the pulse width.

When the amount of power supplied to the heater is decreased by increasing the current flowing through the heater by decreasing the resistance value of the heater instead of increasing the pulse width, the wiring connected in series with the heater and the on-resistance of the transistor are reduced. Of the total power consumption determined by the ratio between the added resistance value and the heater resistance value, the power use efficiency of the heater is reduced.

That is, in a printer that performs high-speed printing, the increase in the number of simultaneous ejection nozzles and the increase in the pulse frequency is a factor that further increases power consumption.

In order to increase the power use efficiency, the heater resistance is increased in order to increase the ratio of the resistance (parasitic resistance), which is the sum of the wiring resistance connected in series with the heater and the ON resistance of the transistor, to the heater resistance. It is necessary to increase the power supply voltage to cope with the decrease in the input energy. However, since the power supply voltage cannot be increased beyond the withstand voltage of the transistor for driving the heater, there is a problem that the maximum value of the power supply voltage is determined by the withstand voltage of the transistor.

Next, the operation when driving the heater will be described with reference to FIG.

The curve in FIG. 7 shows I when the gate voltage of an N-type MOS transistor (NMOS) is used as a parameter.
The graph shows d-Vds characteristics.

A straight line (load line) falling to the right is a characteristic having a slope of a resistance value obtained by adding the heater resistance value and the parasitic resistance value, based on the power supply voltage. The current flowing through the heater moves on the intersection of the NMOS curve and the load curve,
The point on the load line when the gate voltage is increased from 0 V to a desired voltage is the current flowing through the heater at each gate voltage. When the Vds voltage is further increased, the current rapidly increases at the drain, and avalanche breakdown occurs in the drain region. This rapid current rise is caused by NMOS
This causes problems such as destruction and deterioration of the product. For this reason, a low power supply voltage is set so that the load line does not pass through this region.

FIG. 11 shows the substrate current (Isub) characteristics when the gate voltage is used as a parameter. The region where the substrate current increases is the avalanche-Id-Vds characteristic.
It almost coincides with the breakdown area. The increase of the Isub current means that the avalanche breakdown does not occur.
The Isub current flows through the substrate resistance existing between the substrate contacts that collect the sub current, causing the substrate potential to rise, causing a latch-up in which the current remains flowing even when the transistor is turned off.

When the operation along the load line in FIG. 10 is considered, the Isub current flows as follows.

As the intersection is moved along the load line, increasing the gate voltage increases the drain current and then decreases the drain voltage. When the Isub current corresponding to each gate voltage and Vds is obtained, the characteristics shown in FIGS. 12 and 13 are obtained.

Since the drain voltage increases in the region where the gate voltage is low, the Isub current increases. The increase in the Isub current in the region where the gate voltage is low raises the substrate potential and causes latch-up.

Conventionally, as shown in Japanese Patent Application Laid-Open No. H11-138775, a resonance circuit is formed by the influence of parasitic elements other than a MOS transistor and a driving heater resistor, and causes a malfunction in a current waveform during switching. Driving methods have been devised so that the rising and falling of the current waveform does not become steep due to the occurrence of ringing. However, if the gate voltage of the MOS transistor is lowered with a time constant in order to smooth the falling waveform, the low state of the gate voltage is maintained.
There has been a problem in that the conduction time of the Isub current is prolonged, and latch-up due to the Isub current is easily caused.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an ink jet recording head, a method of driving the same, which can reduce ringing in a voltage waveform for driving a heater and increase the resistance to latch-up. It is to provide a recording device.

[0024]

In order to solve the above-mentioned problems and achieve the object, an ink jet recording head according to the present invention comprises a plurality of heating elements and switching means for driving the plurality of heating elements. In an ink jet recording head having a MOS transistor, a voltage waveform applied to a gate of the MOS transistor for transitioning the MOS transistor from on to off includes a first voltage waveform and a first voltage waveform following the first voltage waveform. 2, the voltage change amount per unit time of the second voltage waveform is set to be larger than the voltage change amount per unit time of the first voltage waveform.

A method of driving an ink jet recording head according to the present invention is a method of driving an ink jet recording head having a plurality of heating elements and MOS transistors as switching means for driving the plurality of heating elements.
And a second voltage waveform following the first voltage waveform, and the voltage change per unit time of the second voltage waveform is the voltage change per unit time of the first voltage waveform. Is applied to the gate of the MOS transistor for transitioning the MOS transistor from on to off.

An ink jet recording apparatus according to the present invention is an ink jet recording apparatus which performs recording by driving an ink jet recording head having a plurality of heating elements and a MOS transistor as a switching means for driving the plurality of heating elements. A first voltage waveform and the first voltage waveform;
And a second voltage waveform following the second voltage waveform.
A voltage waveform in which the voltage change amount per unit time of the voltage waveform is set to be larger than the voltage change amount per unit time of the first voltage waveform. And control means for applying the voltage to the gates.

[0027]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The embodiment described below is an example as a means for realizing the present invention, and the present invention can be applied to a modification or modification of the following embodiment without departing from the gist thereof. . [Schematic Description of Apparatus Main Body] FIG. 1 is an external perspective view showing an outline of a configuration of an ink jet printer IJRA which is a typical embodiment of the present invention.

In FIG. 1, a helical groove 500 of a lead screw 5005 which rotates through driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotation of a driving motor 5013.
The carriage HC engaged with the carriage 4 has a pin (not shown) and is reciprocated in the directions of arrows a and b. An ink jet cartridge IJC is mounted on the carriage HC. Reference numeral 5002 denotes a paper pressing plate, which presses the paper against the platen 5000 in the moving direction of the carriage. Reference numerals 5007 and 5008 denote home position detecting means for confirming the presence of the lever 5006 of the carriage in this area and switching the rotation direction of the motor 5013. A member 5016 supports a cap member 5022 for capping the front surface of the recording head.
Reference numeral 5015 denotes a suction unit that suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. Reference numeral 5017 denotes a cleaning blade. Reference numeral 5019 denotes a member which allows the blade to move in the front-rear direction. These members are supported by a main body support plate 5018. It goes without saying that the blade is not limited to this form, and a well-known cleaning blade can be applied to this embodiment. Also, 5012 is
The lever for starting suction for suction recovery moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the drive motor is movement-controlled by known transmission means such as clutch switching.

The capping, cleaning, and suction recovery are configured so that desired processing can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. If a desired operation is performed at a timing, any of the examples can be applied. [Description of Control Configuration] Next, a control configuration for executing the recording control of the above-described apparatus will be described.

FIG. 2 shows an ink jet printer IJRA.
FIG. 3 is a block diagram showing a configuration of a control circuit of FIG.

In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, and 1701 is an MP
Reference numerals U and 1702 denote program ROMs for storing control programs executed by the MPU 1701, and 1703 denotes a dynamic RAM for storing various data (such as the recording signals and recording data supplied to the head). 1704
A gate array for controlling supply of print data to the print head 1708;
Data transfer between the PU 1701 and the RAM 1703 is also controlled. Reference numeral 1710 denotes a carrier motor for transporting the recording head 1708, and reference numeral 1709 denotes a transport motor for transporting the recording paper. Reference numeral 1705 denotes a head driver for driving the head, and reference numerals 1706 and 1707 denote transport motors 170, respectively.
9. A motor driver for driving the carrier motor 1710.

The operation of the above control configuration will be described. When a recording signal enters the interface 1700, the gate array 17
04 and the MPU 1701 converts the recording signal into recording data for printing. Then, the motor driver 17
06 and 1707 are driven, and the head driver 1
The recording head is driven according to the recording data sent to 705, and printing is performed. [Detailed Configuration of Recording Head] FIG. 3 is a perspective view showing the configuration of the ink jet recording head of this embodiment.

In FIG. 3, reference numeral 1 denotes a heating resistor for forming an electrothermal conversion element for generating heat in response to energization and causing foaming of the ink to discharge the ink, and is disposed on the substrate 21 together with the wiring. It is formed through the same manufacturing process as a semiconductor. 25 is a discharge port 22 corresponding to the heating resistor 1
And a liquid path forming member for forming the liquid path 23 communicating with the liquid path. Reference numeral 24 denotes a liquid chamber common to the respective liquid paths 23, and stores ink supplied from an ink supply source (not shown). 26 is a top plate.

Next, the configuration and operation of a drive circuit for driving the recording head shown in FIG. 3 will be described. The head drive circuit is formed on the substrate 21 through the same manufacturing process as that of the semiconductor.

In the following, the case where the heater is driven by the NMOS transistor will be described. [First Embodiment] FIG. 4 is a diagram showing a driving waveform of a gate voltage of an NMOS transistor as a switching element according to a first embodiment of the present invention. FIG. 5 is a circuit diagram of a heater driven by the waveform of FIG.

4 and 5, R1 is a heater as a heating resistor, M1 is an NMOS transistor, Vg is an input terminal of a drive waveform, and a current is connected to VH.

In this embodiment, the NMOS transistor M1
4 changes from on to off, that is, at the falling portion of the drive waveform shown in FIG. 4, the transistor M1 is turned on by the gate voltage Vg1, the transistor M1 is turned off by Vg3, and Vg2 is 13 Isu
In the b-Vgs characteristic, it is a voltage immediately before the Isub current starts to increase when the gate voltage is gradually decreased from Vg1.

The voltage change per unit time from Vg2 to Vg3 is set to be larger than the voltage change per unit time from the gate voltage Vg1 to Vg2.

When the gate voltage of the transistor M1 changes from Vg1 to Vg2, the current flowing through the heater R1 gradually decreases as the gate voltage decreases. At this time, the amount of voltage drop in the heater gradually decreases due to the decrease in the current flowing through the heater, so that the drain voltage of the transistor M1 increases. When the gate voltage changes from Vg2 to Vg3, the current flowing through the heater further decreases, so that the drain voltage of the transistor M1 rises to around VH.

Due to the rise of the drain voltage, Isub
The current starts to flow for a long time. However, the transition time from Vg2, which is the gate voltage at which the Isub current flows, to Vg3 is short, and the voltage change is sharp, so that the conduction time of the Isub current can be shortened.

A transistor generating an Isub current and I
When the Isub current flows through the parasitic resistance interposed between the substrate contact portion for collecting the sub current and the capacitance distributed in the resistance, the substrate potential rises with a time constant.
By shortening the conduction time of the Isub current, the rise and time of the substrate potential can be suppressed, and as a result, latch-up can be suppressed. When the gate voltage is Vg1
By making the transition time from Vg2 to Vg2 longer, a steep change in the heater current can be suppressed, and malfunction due to current ringing can be suppressed. [Second Embodiment] FIG. 6 is a diagram showing a driving waveform of a gate voltage of an NMOS transistor as a switching element according to a second embodiment of the present invention. FIG. 7 is a circuit diagram of a heater driven by the waveform of FIG.

The gate voltages G1 and G2 in FIG. 6 represent waveforms input to the gates G1 and G2 of the transistors M2 and M3 in FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

6 and 7, L1 is a load element or a switching element connected to a power supply, and M2,
M3 is an NMOS transistor. Transistor M
2 and M3 are turned on when the gate voltages G1 and G2 are at "High" level and turned off when the gate voltages G1 and G2 are at "Low" level. When the gate voltage of the transistor M2 becomes “High”, the output level of the transistor M2 becomes “Low”, and the transistor M1 is turned off. When the gate voltage G1 of the transistor M2 is "Low", the output level of the transistor M2 becomes "High" via the load element L1, and the transistor M1 is turned on.

In FIG. 6, when the gate voltage G1 is "Lo"
When the transition from “w” to the “High” level occurs, the transistor M1 transitions from on to off, and at this time, the gate input terminal G2 of the transistor M3 transitions from on to off.
2 changes from off to on, the transistor M1
Is discharged through the transistor M2, and gradually decreases with a time constant determined by the parasitic capacitance of the gate terminal of the transistor M1 and the on-resistance of the transistor M2. At this time, when the transistor M3 is turned on, the charge accumulated in the transistor M1 is rapidly discharged, and a gate voltage waveform as shown in FIG. 4 is obtained.

That is, the operation from the time when the transistor M1 is turned on to the time when it is turned off is the same as that of the first embodiment, and has the effect of suppressing the latch-up. [Third Embodiment] FIG. 8 is a circuit diagram of a heater driving circuit according to a third embodiment of the present invention. FIG. 9 is a diagram showing an example of a change in drain capacitance when the drain voltage is changed with reference to the substrate potential of the PMOS.

In FIG. 8, M4 is a PMOS transistor, and the drain terminal of M4 is connected to the gate terminal of M1. B1 is a logic circuit that drives the gate of M1. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

When the transistor M1 changes from on to off, the logic circuit B1 changes the gate voltage of the transistor M1 from "High" level to "Low" level. The voltage difference between the drain voltage and the power supply voltage VDD at this time increases as the gate voltage of the transistor M1 decreases. As shown in FIG. 9, when the reference potential of the transistor M4 is connected to the power supply voltage VDD, the capacitance at the drain terminal of the transistor M4 decreases as the gate voltage of the transistor M1 decreases.

That is, at the same time as the gate voltage of the transistor M1 decreases, the transistor M4 connected to the gate
Of the transistor M1, the fall of the drive waveform of the gate voltage of the transistor M1 becomes steeper as the gate voltage becomes lower. This is because, similarly to the first embodiment, when the gate voltage is low, the transition time of the gate voltage is shortened, and the conduction time of the Isub current is also shortened, so that the latch-up is suppressed.

As described above, according to the present embodiment, a voltage waveform having a time constant is applied to the gate in a region where the gate voltage is high when the NMOS transistor transitions from on to off and the Isub current is low. By steepening the voltage waveform in a region where the gate voltage is low and the Isub current increases, the ringing in the voltage waveform for driving the heater can be reduced and the tolerance of latch-up can be increased.

In the above embodiment, the description has been made assuming that the droplets ejected from the recording head are ink, and that the liquid stored in the ink tank is ink. It is not limited. For example, an ink tank may contain a processing liquid discharged to a recording medium in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

The above-described embodiment is particularly provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection even in an ink jet recording system. By using a method in which a change in the state of the ink is caused by energy, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the nucleate boiling to the electrothermal transducer arranged corresponding to the sheet or the liquid path in which Since thermal energy is generated in the electrothermal transducer and film boiling occurs on the heat-acting surface of the recording head, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of the liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting surface is arranged in a bent region, is also included in the present invention. In addition, for multiple electrothermal transducers,
JP-A-59-123670 which discloses a configuration in which a common slot is used as a discharge part of an electrothermal transducer, and JP-A-59-123670 which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge part. A configuration based on 138461 may be adopted.

Further, 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 determined by a combination of a plurality of recording heads as disclosed in the above-mentioned specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition to the cartridge type recording head in which the ink tank is provided integrally with the recording head itself described in the above embodiment, the recording head is electrically connected to the apparatus main body by being mounted on the apparatus main body. A replaceable chip-type recording head, which enables a simple connection and supply of ink from the apparatus main body, may be used.

It is preferable to add recovery means for the print head, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be a single recording head or a combination of plural recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the above-described embodiment, the description has been made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, it is possible to use an ink that softens or liquefies at room temperature. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy as energy for changing the state of the ink from a solid state to a liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be provided not only as an image output terminal of an information processing apparatus such as a computer but also integrally or separately, a copying apparatus combined with a reader or the like, and a transmission / reception apparatus. It may take the form of a facsimile machine having functions.

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. Or a CPU or MPU) reads out and executes the program code stored in the storage medium,
Needless to say, this is achieved. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.
In addition, by the computer executing the readout program code, not only the functions of the above-described embodiments are realized, but also based on the instructions of the program code,
The operating system (OS) running on the computer performs part or all of the actual processing,
It goes without saying that a case where the functions of the above-described embodiments are realized by the processing is also included.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs a part or all of the actual processing,
It goes without saying that a case where the functions of the above-described embodiments are realized by the processing is also included.

[0065]

As described above, claims 1, 6, 1
According to the first aspect, the first voltage waveform includes a second voltage waveform following the first voltage waveform, and a voltage change amount per unit time of the second voltage waveform is the first voltage waveform. Applying a voltage waveform set larger than the amount of voltage change per unit time of the waveform to the gate of the MOS transistor for transitioning the MOS transistor from ON to OFF reduces ringing and increases the latch-up resistance. it can.

According to the second, seventh and twelfth aspects of the present invention, the MO
The drain of the first MOS transistor and the drain of the second MOS transistor are connected in parallel to the gate of the S transistor, and the voltage waveforms applied to the gates of the first and second MOS transistors are the third respectively. And the fourth waveform, wherein the first MOS transistor is turned on by the third waveform, and the second MOS transistor is turned on by the fourth waveform after the third waveform, whereby the latch is performed. Up can be suppressed.

According to the third, eighth and thirteenth aspects of the present invention, the MO
The capacitance connected to the gate of the S transistor monotonically decreases as the voltage waveform applied to the gate for switching the MOS transistor from on to off changes, so that latch-up can be suppressed.

According to the fourth, ninth and fourteenth aspects of the invention, the recording head is an ink jet recording head that performs recording by discharging ink, so that the number of simultaneously discharging nozzles can be increased and the recording time can be shortened. .

According to the fifth, tenth and fifteenth aspects of the present invention, the recording head is a recording head for discharging ink using thermal energy, and is a thermal energy converter for generating thermal energy applied to the ink. Is provided, the number of simultaneous ejection nozzles can be increased, and the recording time can be shortened.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an outline of a configuration of an ink jet printer IJRA which is a typical embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a control circuit of the inkjet printer IJRA.

FIG. 3 is a perspective view illustrating a configuration of an inkjet recording head according to the embodiment.

FIG. 4 is a diagram showing a driving waveform of a gate voltage of an NMOS transistor as a switching element according to the first embodiment of the present invention.

5 is a circuit diagram of a heater driven by the waveform of FIG.

FIG. 6 is a diagram showing a driving waveform of a gate voltage of an NMOS transistor as a switching element according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram of a heater driven by the waveform of FIG.

FIG. 8 is a drive circuit diagram of a heater according to a second embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a change in drain capacitance when a drain voltage is changed with reference to a substrate potential of a PMOS.

FIG. 10 shows Id-Vds characteristics of an NMOS transistor.

FIG. 11 shows Isub-Vgs characteristics of an NMOS transistor.

FIG. 12 shows Isub-Vgs characteristics of an NMOS transistor.

FIG. 13 is an Isub-Vgs characteristic of an NMOS transistor.

FIG. 14 is a diagram showing a conventional heater drive circuit.

Claims (15)

[Claims] 1. An ink jet recording head having a plurality of heating elements and a MOS transistor as a switching means for driving the plurality of heating elements, a gate of the MOS transistor for transitioning the MOS transistor from on to off. Is a first voltage waveform and a second voltage waveform following the first voltage waveform.
An ink jet recording head, comprising: a voltage change amount per unit time of the second voltage waveform set to be larger than a voltage change amount per unit time of the first voltage waveform. 2. The drain of a first MOS transistor and the drain of a second MOS transistor are connected in parallel to the gate of the MOS transistor, and are applied to the gates of the first and second MOS transistors. The voltage waveforms are composed of third and fourth waveforms, respectively. The third waveform turns on the first MOS transistor, and the second waveform lags behind the third waveform to turn on the second MOS transistor. The inkjet recording head according to claim 1, wherein the inkjet recording head is turned on. 3. The capacitance connected to the gate of the MOS transistor monotonically decreases as the voltage waveform applied to the gate for transitioning the MOS transistor from on to off changes. Item 3. An ink jet recording head according to Item 2. 4. The ink jet recording head according to claim 1, wherein the recording head is an ink jet recording head that performs recording by discharging ink. 5. The recording head according to claim 1, wherein the recording head discharges ink by using thermal energy, and includes a thermal energy converter for generating thermal energy to be applied to the ink. Item 2. An ink jet recording head according to item 1. 6. A method of driving an ink jet recording head having a plurality of heating elements and a MOS transistor as a switching means for driving the plurality of heating elements, comprising: a first voltage waveform; A voltage waveform composed of a second voltage waveform following the waveform, wherein the voltage change amount per unit time of the second voltage waveform is set to be larger than the voltage change amount per unit time of the first voltage waveform, The MOS
The MO for transitioning the transistor from on to off
A method for driving an ink jet recording head, wherein the method is applied to a gate of an S transistor. 7. A drain of a first MOS transistor and a drain of a second MOS transistor are connected in parallel to the gate of the MOS transistor, and are applied to the gates of the first and second MOS transistors. The voltage waveforms are composed of third and fourth waveforms, respectively. The third waveform turns on the first MOS transistor, and the second waveform lags behind the third waveform to turn on the second MOS transistor. The method according to claim 6, wherein the method is turned on. 8. The capacitor connected to the gate of the MOS transistor monotonically decreases as the voltage waveform applied to the gate for transitioning the MOS transistor from on to off changes. Item 7. A method for driving an ink jet recording head according to Item 6. 9. The method according to claim 6, wherein the recording head is an inkjet recording head that performs recording by discharging ink. 10. The recording head according to claim 1, wherein the recording head ejects ink by using thermal energy, and includes a thermal energy converter for generating thermal energy to be applied to the ink. Item 7. A method for driving an ink jet recording head according to Item 6. 11. An ink jet recording apparatus which performs recording by driving an ink jet recording head having a plurality of heating elements and a MOS transistor as a switching means for driving the plurality of heating elements, wherein: , A second voltage waveform following the first voltage waveform, and the voltage change per unit time of the second voltage waveform is larger than the voltage change per unit time of the first voltage waveform. The set voltage waveform is
The MO for transitioning the transistor from on to off
An ink jet recording apparatus comprising a control means for applying a voltage to the gate of an S transistor. 12. The gate of the MOS transistor,
A drain of a first MOS transistor and a second MOS transistor
The drains of the transistors are connected in parallel, and the voltage waveforms applied to the gates of the first and second MOS transistors comprise third and fourth waveforms, respectively.
12. The ink jet recording apparatus according to claim 11, wherein the first MOS transistor is turned on by the waveform, and the second MOS transistor is turned on by the fourth waveform after the third waveform. 13. The method according to claim 1, wherein the capacitance connected to the gate of the MOS transistor monotonically decreases as the voltage waveform applied to the gate for changing the MOS transistor from on to off changes. Item 1
2. The ink jet recording apparatus according to 1. 14. The ink jet recording apparatus according to claim 11, wherein the recording head is an ink jet recording head that performs recording by discharging ink. 15. The recording head according to claim 1, wherein the recording head ejects ink by using thermal energy, and includes a thermal energy converter for generating thermal energy to be applied to the ink. Item 12. An ink jet recording apparatus according to item 11.