JP3332745B2 - Printing head and printing apparatus using the printing head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head and a recording apparatus using the recording head, and more particularly, to a recording head for performing recording by an ink jet system and a recording apparatus using the recording head.

[0002]

2. Description of the Related Art Ink-jet recording is characterized by the fact that noise during the recording is extremely small to a negligible level, that high-speed recording is possible, and that so-called plain paper is used without requiring any special processing. Recently, much interest has been attracted because of its advantages such as the ability to fix recorded images.

Among them, for example, Japanese Patent Application Laid-Open No. 54-518
No. 37, German publication (DOLS) 2843064
The recording method described in Japanese Patent Application Laid-Open Publication No. H10-15095 has a feature that is different from other inkjet recording methods in that thermal energy is applied to a liquid such as ink to obtain a driving force for discharging droplets. .

That is, according to the recording method disclosed in the above-mentioned publication, the liquid which has been subjected to the action of thermal energy undergoes a state change accompanied by a steep increase in volume, and the action based on the state change causes an action based on the state change. The liquid is ejected from the orifice to form flying droplets, and the droplets adhere to the recording medium to perform recording.

[0005] In particular, according to the recording method disclosed in DOLS No. 2843064, not only is it very effectively applied to so-called drop-on-demand recording, but it has a recording width corresponding to the entire width of a recording medium. Since a full-line type recording head having a high-density orifice can be easily realized, there is an advantage that a high-resolution and high-quality image can be obtained at a high speed.

A recording head of a recording apparatus to which such a recording method is applied is provided with an orifice provided for discharging a liquid and a thermal energy for discharging a liquid droplet which communicates with the orifice. A liquid flow path having a heat acting part, which is a part acting on the substrate, as a part of the structure, and a substrate provided with an electrothermal converter (heating element) for generating thermal energy.

In recent years, not only are a plurality of heating elements formed on such a substrate, but also a plurality of drivers for driving the respective heating elements, and image data input in series from a printing apparatus are transferred in parallel to the respective drivers. To temporarily store image data having the same number of bits as the number of heating elements, and a logic circuit such as a latch circuit for temporarily latching data output from the shift register,
It can be mounted on the same substrate.

FIG. 6 is a block diagram showing a configuration of a logic circuit of a conventional print head having N heating elements (print elements).

In FIG. 6, reference numeral 700 denotes a substrate, 701 denotes a heating element, 702 denotes a power transistor, 703 denotes an N-bit latch circuit, and 704 denotes an N-bit shift register.
Reference numeral 715 denotes a sensor for monitoring the resistance value of the heating element 701 and the temperature of the substrate 700, and a heater for keeping the substrate 700 warm. A plurality of these sensors and heaters may be mounted, or the sensors and heaters may be integrally formed. Reference numerals 705 to 714 and 716 denote input / output pads. In these input / output pads, reference numeral 705 denotes a clock (C) for operating the shift register 604.
LK), a clock input pad for inputting image data (DATA) serially, 706 a latch input pad for inputting a latch clock (LTCLK) for holding image data in the latch circuit 703 , 708 are power transistors 702
Is turned on, a drive signal input pad for inputting a heat pulse (HEAT) for externally controlling the drive time when the heating element 701 is energized, and 709 is a logic circuit drive power supply (3 to 8 V, generally 5 V) 710 is a GND terminal, 711 is a heating element power input pad for inputting power for driving the heating element 701, and 712 is a reset signal (RST) for initializing the latch 703 and the shift register 704. Reset input pad, 7
Reference numeral 13 denotes a terminal for a heating element drive power supply.

Reference numerals 714- (1) to 714- (n) denote monitor signal output pads and control signal input pads for driving the sensor and the heater. Furthermore, 716-
(1) to 716 (n) are block selection signals (BLK1, BLK2,..., BLK) for selecting blocks when dividing the N heating elements into n blocks and performing time-division driving.
n) is a block selection signal input pad for inputting n). 717 is an output from the latch circuit 703, a heat signal (HEAT), and a block selection signal (BLK1,
AND for calculating a logical product with BLK2,..., BLKn)
Circuit.

The driving sequence of the recording head having the above configuration is as follows. Here, the image data (D
ATA) is binary data of one bit per pixel.

First, when image data (DATA) is serially output from a main body of a printing apparatus equipped with a print head in synchronization with a clock (CLK), the data is taken into a shift register 704. Next, the captured image data (DATA) is temporarily stored in the latch circuit 703, and is turned on according to the value of the image data (“0” or “1”).
The / OFF output is output from the latch circuit 703.

In such a state, the heat pulse (HEA
T) and the block selection signal, the latch circuit 7
03, the power transistor corresponding to the heating element whose block is selected by the block selection signal is supplied with the input heat pulse (HEA).
The drive is performed only during the time when T) is ON, whereby a current flows through the corresponding heating element to execute a recording operation.

In the logic circuit of the recording head shown in FIG. 6, an example is shown in which an NPN-type bipolar transistor is used for the power transistor 702 and the logic circuit is formed using a BiCMOS process. By using a MOSFET, the logic circuit may be formed by changing the manufacturing process from a BiCMOS process to a CMOS process. This is because not only can the number of steps in the manufacturing process be reduced, but also there are advantages in that the space for element isolation can be reduced and the size of the substrate can be reduced.

This will be described more specifically with reference to FIGS.

FIG. 7 is a logic circuit diagram showing only a power transistor that drives one heating element when a bipolar transistor is used as a power transistor.
FIG. 7A shows an NPN-type bipolar transistor 70.
FIG. 7 is an equivalent circuit diagram in which 2, 702 'are formed in a two-stage configuration.
(B) is a sectional view of the circuit board. In FIG. 7A, a logic output 721 is an output of the AND circuit 717. FIG. 7B shows how the N region 723, 725, 726, and 727 and the P region 72 are formed on the circuit board in order to configure an NPN-type bipolar transistor.
4, 728 and 729 are formed.
B, E, and C indicate a base, an emitter, and a collector, respectively.

FIG. 8 shows a MOSFET as a power transistor.
FIG. 4 is a cross-sectional view of a substrate in a case where the entire logic circuit is formed by a CMOS process.

FIG. 8A is an equivalent circuit diagram when an NMOS 720 is used as a power transistor for driving one heating element, and FIG. 8B is a cross-sectional view of a substrate constituting the circuit shown in FIG. FIGS. 8C and 8D are cross-sectional views of substrates constituting NMOS and PMOS used for logic circuits such as the latch circuit 703 and the shift register 704, respectively. 8 (b) to 8 (d), S, G,
D is a source, a gate, and a drain, respectively, 731;
732 and 736 are N regions, and 733 to 735 are P regions.

When a MOSFET is used as a power transistor, the entire logic circuit can be formed by a CMOS process. In the BiCMOS process, an NMOS transistor (FIG. 8C) and a PMOS
The high-concentration N for the collector shown in FIG. 7B which was necessary separately from the formation of the CMOS comprising the transistor (FIG. 8D).
Region 726, 727, N-type epitaxial layer 725,
The P-type element isolation 729 and the like become unnecessary.

The MOS power transistor type often uses an NMOS transistor for reasons such as electron mobility. However, when the power transistor is used for a logic circuit of a recording head of an ink jet system, its drain (when the power transistor is not driven) is used. Considering that a voltage of 20 V or more is applied to D), a low-concentration N-type region 732 is formed in the drain region as shown in FIG. MOS transistor).

Next, a booster circuit necessary for driving the power transistor will be described.

Applying a logic output 721 having a voltage of about 3 to 8 V (generally 5 V) to the gate (G) of a power transistor as shown in FIG. At least 100 to 20
It is difficult to pass a current of 0 mA to the heating element, and even when this is possible, the ON voltage between the drain (D) and the source (S) increases, and energy is wasted. Therefore, in order to improve the driving capability of the power transistor, usually, the gate voltage booster 7 boosts the voltage applied to the gate (G) of the power transistor.
40 is provided before the NMOS power transistor 720. There are several circuit configurations, examples of which are described below.

FIG. 9 is an example showing the configuration of the gate voltage boosting section 740. In FIG. 9, reference numeral 401 denotes an offset NMOS, 402 denotes a step-up resistor, and 403 denotes an operational amplifier. Reference numeral 404 denotes a driving voltage (VH) input from the heating element power supply input pad 711. This circuit has a configuration of an NMOS inverter using an offset NMOS 401.

However, in this circuit configuration, when the heating element is not driven, that is, when the power transistor 720 is off, the NMOS 401 turns on and the power supply voltage (VH) applied from the power supply via the boosting resistor 402.
Current flows through 404. Since this current continues to flow while the heating element is not driven, not only energy loss occurs, but also when the number of heating elements increases, the current alone may increase the internal temperature of the recording head.

FIG. 10 is another example showing the configuration of the gate voltage boosting section 740. In FIG. 10, 401 'is an offset NMOS, 405 is an inverter, and 406 is a withstand voltage of 1
A PMOS 407 of 0 to 14 V has a power supply voltage (VH ') of 14 V or less supplied from another power supply. Such a circuit configuration has an advantage that no current flows to the gate voltage boosting unit 740 when the heating element is not driven, that is, when the power transistor 720 is off.

However, in this circuit configuration, the PMO
The withstand voltage in S406 is not so high, and it is difficult to obtain a sufficient withstand voltage in the range of the power supply voltage (VH) for driving the heating element (about 10 to 30 V), and the PMOS 406 can withstand a bias (about 10 to 30 V). Another power supply voltage (VH ') 407 of 14 V or less is supplied separately from the outside, or
It is necessary to lower the power supply voltage (VH) inside the circuit to generate a power supply voltage for the gate voltage booster 740. Therefore, there are problems such as the necessity of another power supply, the occurrence of power loss due to step-down, and the step-down voltage fluctuating depending on the number (load) of the driving heating elements.

FIG. 11 shows still another example of the configuration of the gate voltage boosting section 740. In FIG. 11, 408 is N
As in the case of the MOS power transistor 720, this is a PMOS in which a low-concentration impurity layer is formed in the drain to form an offset type and the withstand voltage is increased to 30 V or more. With such a configuration, the power supply voltage (VH) 404 for driving the heating element is shared with the power supply voltage for the gate voltage boosting unit 740 to eliminate the need for a separate power supply and to reduce the power supply voltage (VH). Eliminating the need to

[0028]

However, in the above conventional example, the following problems still remain when the power transistor serving as the drive circuit of the recording head is a MOSFET. (1) For example, the gate voltage booster 740 shown in FIG.
In FIG. 9, since an inverter is added as compared with that shown in FIG. 9, the circuit scale of the gate voltage boosting unit increases, which leads to an increase in the size of the substrate chip, that is, an increase in cost. (2) When switching is performed in a state where a voltage of 25 V or more is applied between the drain and the source of the NMOS which is a power transistor, electrons which are carriers are accelerated by the high voltage between the drain and the source at the moment when the NMOS is turned off. A phenomenon of impact ionization in which ions collide with Si atoms occurs, which causes a large current leak between the drain and the source. If this phenomenon occurs, there is a high possibility that the entire substrate will be destroyed. (3) When the heating element is not driven, a potential difference between the heating element and the substrate surface, such as silicon (Si), which is in contact with the ink and the substrate, affects the life of the recording head.
Specifically, in the case of a substrate on which an NMOS for driving a heating element is mounted, an element is generally formed on a P-type silicon (Si) substrate. In this case, while the P-type substrate portion becomes GND, the ink goes around the side of the base and is electrically short-circuited with the substrate. Now, since the ink has conductivity, the entire ink is always at GND. Under these conditions, when the NMOS is off, the part of the base including the heating element, which is in contact with the ink, is mostly connected to the power supply voltage (V) for driving the heating element via the protective insulating film.
H). When the power is supplied to the printhead and the printhead on which it is mounted, the time during which power is actually supplied to the heating element is only a fraction of the time. No operation is performed. Therefore, an electric field is continuously generated on the ink and the substrate surface for a very long time, which shortens the life of the protective insulating film, that is, shortens the life of the recording head.

The present invention has been made in view of the above-mentioned conventional example, and has as its object to provide a recording head having a simple circuit configuration, high reliability, and a long service life, and a recording apparatus using the recording head. The purpose is.

[0030]

To achieve the above object, a recording head according to the present invention has the following arrangement.

That is, a heating element for recording by generating heat by energizing with a predetermined power supply voltage, a PMOS transistor having a high withstand voltage for driving the heating element, and an applied voltage applied by inputting a recording signal are boosted. A circuit for outputting to the gate of the PMOS transistor, a high withstand voltage NMOS transistor to which the recording signal is gate-input is disposed on a ground side between the power supply voltage terminal and the ground; And a booster circuit that outputs a signal between the NMOS transistor and the booster resistor to the gate of the high-withstand-voltage PMOS transistor. A recording head is provided between the voltage terminal and the ground, wherein the high breakdown voltage PMOS transistor and the heating element are connected in series from the power supply voltage terminal side.

According to another aspect of the present invention, there is provided a recording apparatus using the recording head having the above configuration.

In the recording head having the above configuration, P
An offset type MOS transistor and NMOS transistor can be used.

The PMOS transistor and NMO
The S transistor can be configured to be driven by a predetermined power supply voltage, and the heating element, the PMOS transistor, and the NMOS transistor are formed on a P-type silicon substrate.

[0035]

The above-mentioned recording head is preferably an ink jet recording head which performs recording by discharging ink. Then, the ink is in contact with the heating element with the electric insulating layer interposed therebetween, and the ink is heated by the heating element during a printing operation.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

<Schematic Description of Apparatus Main Body> FIG. 1 shows an ink jet printer IJ which is a typical embodiment of the present invention.
It is an external appearance perspective view showing the outline of composition of RA. In FIG. 1, a carriage HC that engages with a spiral groove 5004 of a lead screw 5005 that rotates via driving force transmission gears 5009 to 5011 in conjunction with forward and reverse rotation of a drive motor 5013 has pins (not shown). Guide rail 50
03 reciprocates in the directions of arrows a and b. The carriage HC includes a recording head IJH and an ink tank IT.
Integrated inkjet cartridge IJC
Is installed. Reference numeral 5002 denotes a paper pressing plate, which feeds the recording paper P to the platen 50 over the moving direction of the carriage HC.
Press against 00. Reference numerals 5007 and 5008 denote photocouplers, which are home position detectors for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a cap member 50 for capping the front surface of the recording head IJH.
Reference numeral 5015 denotes a suction device that suctions the inside of the cap, and performs suction recovery of the recording head through an 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 known cleaning blade can be applied to this example. Reference numeral 5021 denotes a lever for starting suction for recovery of suction. The lever 5021 moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor is controlled by a known transmission mechanism such as clutch switching. Is done.

The capping, cleaning, and suction recovery are configured so that desired operations 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 the timing, any of the embodiments can be applied.

Further, the ink jet printer IJRA having the above-described configuration is provided with a recording paper automatic feeder (not shown).
Is provided to automatically feed the recording paper P.

<Description of Control Structure> Next, a control structure for executing the recording control of the above-described apparatus will be described.

FIG. 2 is a block diagram showing a configuration of a control circuit of the ink jet printer IJRA. In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, 1701 is an MPU, 1702 is an MPU 170
ROM for storing a control program to be executed by PC 1, 170
Reference numeral 3 denotes a DRAM for storing various data (such as the print signal and print data supplied to the print head IJH). Reference numeral 1704 denotes a gate array (GA) for controlling supply of print data to the print head IJH, and includes an interface 1700, an MPU 1701, and a RAM 1703.
It also controls data transfer between them. 1710 is a recording head IJ
A carrier motor for transporting H, and 1709 a transport motor for transporting the recording paper. 1705, a head driver for driving the recording head IJH, 1706, 1707
Are the transport motor 1709 and the carrier motor 171 respectively.
0 is a motor driver for driving 0.

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
Print head IJH according to the print data sent to
Is driven, and recording is performed.

<Internal Structure of Recording Head IJH> FIG. 3 is a partially broken perspective view showing the internal structure of the recording head IJH.

In FIG. 3, reference numeral 100 denotes a substrate on which a logic circuit is mounted, 500 denotes a discharge port (orifice) for discharging ink, 501 denotes a liquid path for ink, and 502 denotes a liquid path for a plurality of inks to temporarily store ink. 503, an ink supply port for supplying ink from an ink tank (not shown); 504, a top plate; 505, a top plate 504;
A flow path wall member forming an ink liquid path 501 together with
Reference numeral 06 denotes a heating element, and reference numeral 507 denotes wiring for connecting the logic circuit and the heating element 701.

The logic circuit, the heating element 601, and the wiring 607 are
A top plate 504 and a flow path wall member 505, which are formed on the base 100 using a semiconductor manufacturing process, and have an ink supply port 503 attached thereto, are attached to the recording head IJH. Then, the ink injected from the ink supply port 503 is stored in the internal common ink liquid chamber 502 and supplied to each of the liquid paths 501. In this state, the heating element 701 is driven to discharge the ink from the discharge port 600. You.

FIG. 4 is a diagram showing a configuration of a circuit for driving one recording element of the recording head IJH. The configuration of the logic circuit of the printhead IJH is the same as that of the conventional logic circuit shown in FIG. 6, and therefore the description thereof is omitted, and if necessary, the reference numerals described in FIG. The components are mentioned. In addition, the above-described recording element refers to a circuit that includes a heating element that operates to eject ink from one orifice and a power transistor.

In FIG. 4, the gate voltage boosting section 740 is an NMOS type inverter having the same configuration as that of the conventional one shown in FIG. 9, so that the same components as those used in FIG. The description here is omitted.
The on / off state of the logic output 721 shown in FIG. 4 is represented by a voltage of 5V. 101 is a PMOS transistor, and A is a heating element and a wiring portion facing the P-type silicon (Si) substrate and the ink via only the protective insulating film.

In FIG. 4, reference numeral 101 denotes a PM which operates as a power transistor and drives a heating element 701.
OS transistor.

FIG. 5 shows the PMOS transistor 101 and the NMOS transistor 401 of the gate voltage booster 740.
FIG. 3 is a cross-sectional view of a circuit board on which is formed. FIG. 5 (a)
FIG. 5B shows a configuration of the PMOS transistor 101.
2 shows a configuration of a MOS transistor 401.

As shown in FIG. 5A, in the PMOS transistor 101, a low-concentration P-type impurity layer 202 is provided between a high-concentration P-type impurity layer 201 serving as a drain (D) and a gate (G). Structure (offset MOS)
The breakdown voltage of a general PMOS having no offset structure (1
(Approximately 0 to 14 V) to increase the breakdown voltage to 25 V or more.

Also, the NMOS transistor 401
As shown in FIG. 5B, a structure (offset MOS) in which the low-concentration N-type impurity layer 212 is provided between the high-concentration N-type impurity layer 211 serving as the drain (D) and the gate (G) is used. Is increased like the PMOS. This structure is the same as the structure of the offset NMOS shown in FIG.

In FIG. 5, reference numeral 203 denotes an N region,
Reference numeral 04 denotes a P-type silicon (Si) substrate.

Next, the recording elements of the recording head IJH having the above configuration and the operation of the gate voltage booster 740 will be described.

PMOS 101 as a power transistor
Is off, that is, when the heating element 701 is not driven, NM
The OS 401 is also in the off state, and the gate voltage booster 740
, No power flows, that is, when the recording operation is not performed, the power consumption becomes zero. Since the NMOS 401 is an offset MOS and has a high breakdown voltage characteristic, the power supply voltage (VH) 404 is directly applied to the inverter (NMOS 40).
1) is applied.

As described above, the ink is conductive, and is in contact with the P-type silicon (Si) substrate, which is GND, on the base side, so that the entire ink is GND. On the other hand, when the PMOS 101 is off, A in FIG.
The heating element and the wiring portion that are in contact with the ink indicated by the portion via only the protective insulating film become GND. Therefore, no electric field is generated between the ink and the portion A via the protective insulating film.

Therefore, according to the embodiment described above, when no recording operation is performed, no current flows through the gate voltage booster 740, so that the power consumption of the recording head when the recording operation is not performed can be reduced, and the gate voltage can be reduced. Since the boosting section may have a simple configuration, it can contribute to the reduction in the number of elements in the entire circuit. This makes it possible to reduce the circuit size of the recording head and reduce its production cost.

For example, as compared with the conventional circuit configuration shown in FIG. 11, the number of elements of the gate voltage booster per recording element can be reduced to half. Further, when the recording operation is performed by turning on the power of the recording apparatus, the recording cycle for causing the recording head IJH to perform the recording operation is about 200 μS. The recording operation is not performed during most of the recording cycle.
That is, since the power transistor is off, the fact that power consumption does not occur in the gate voltage boosting unit 740 at that time is remarkable from the viewpoint of power consumption reduction.

Further, in the above embodiment, since the PMOS is used as the power transistor, the impact ionization phenomenon in which ions are generated by collision of carriers is less likely to occur than in the case of the NMOS, and the driving of the heating element is turned off. In this case, the occurrence of a leakage current between the drain and the source can be suppressed. Thereby, the reliability of the recording head is improved.

Furthermore, in the above embodiment, when the power transistor is off, no electric field is generated between the ink and the substrate surface, so that the load on the protective insulating film can be reduced. As a result, the life of the substrate can be prolonged, and the reliability of the recording head can be improved.

In the above embodiment, the PMOS 10
Although the example in which the first inverter is constituted by the resistor and the NMOS has been described, the present invention is not limited to this. For example, the inverter may be constituted only by the NMOS.

Further, in the above embodiment, the offset MOS is used for both the PMOS of the power transistor and the NMOS of the gate voltage booster, but the present invention is not limited to this. For example, these MOS
However, in the case where the device can withstand the heating element drive voltage without using the offset type, it is not necessary to use the offset type for one or both of them.

In the above embodiment, the recording head of the ink jet system has been described as an example, but the present invention is not limited to this. For example, the present invention can be applied to a thermal head that performs recording by a thermal transfer method.

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

The typical structure 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 film boiling to the electrothermal transducer arranged corresponding to the sheet or the liquid path holding the 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 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 a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a 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 combining a plurality of recording heads as disclosed in the above 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 is 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 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, as a form of the recording apparatus according to the present invention, in addition to those provided integrally or separately as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, It may take the form of a facsimile machine having functions.

The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copying machine, a facsimile machine). Etc.).

[0076]

As described above, according to the present invention, the circuit size of the recording head is reduced, the current leakage between the drain and source of the power transistor for driving the heating element is suppressed, and the reliability of the recording head is improved. There is an effect that the power consumption of the recording head can be reduced.

Further, according to the configuration of the seventh aspect, when no recording operation is performed, no electric field is generated between the ink and the heating element via the insulating layer, so that the load on the insulating layer can be reduced. This contributes to improving the reliability of the recording head and extending its life.

[0078]

[Brief description of the drawings]

FIG. 1 is an external perspective view illustrating a configuration of a printing apparatus that performs printing according to an inkjet method, which is a typical embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control circuit of the printing apparatus shown in FIG.

FIG. 3 is a partially broken perspective view showing an internal structure of a recording head mounted on the recording apparatus shown in FIG.

FIG. 4 is a diagram illustrating a configuration of a circuit that drives one print element of a print head IJH.

FIG. 5 is a cross-sectional view of a circuit board on which the PMOS transistor 101 and the NMOS transistor 401 of the gate voltage booster 740 are formed.

FIG. 6 is a block diagram showing a configuration of a logic circuit of a conventional printhead.

FIG. 7 is a diagram of a circuit using a bipolar power transistor used to drive one heating element.

FIG. 8 is a cross-sectional view of a substrate when the entire logic circuit is formed by a CMOS process using a MOSFET as a power transistor.

FIG. 9 is an example showing a configuration of a gate voltage booster 740.

FIG. 10 is another example showing a configuration of a gate voltage boosting unit 740.

FIG. 11 is still another example showing the configuration of the gate voltage boosting section 740.

[Explanation of symbols]

 101 PMOS Power Transistor IJH Recording Head

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Toshihiko Ozaki (56) References JP-A-5-16366 (JP, A) JP-A-6-143574 (JP, A) JP-A-4-320848 (JP, A) Kaihei 8-108538 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B41J 2/01 B41J 2/05 B41J 2/355

Claims (7)

(57) [Claims] 1. A heating element for recording by generating heat by energizing with a predetermined power supply voltage, a high-breakdown-voltage PMOS transistor for driving the heating element, and boosting an applied voltage applied by inputting a recording signal. And
A circuit for outputting to the gate of the PMOS transistor.
The recording signal is provided on the ground side between the power supply voltage end and the ground.
Distribution is NMOS transistor having a high withstand voltage but is a gate input
To the power supply voltage end between the power supply voltage end and the ground.
A compression resistor is disposed, and the NMOS transistor and the boost
A signal between the high-resistance PMOS transistor and the high-resistance PMOS transistor.
A booster circuit that outputs the voltage to the gate of the power supply, and the high-voltage PMOS transistor and the heating element are connected in series between the power supply voltage end and the ground in series from the power supply voltage end. Recording head. Wherein before and PMOS transistor of the high withstand voltage
2. The recording head according to claim 1, wherein the high breakdown voltage NMOS transistor is of an offset type. 3. Before the PMOS transistor of the high withstand voltage
2. The recording head according to claim 1, wherein the high breakdown voltage NMOS transistor is driven by the predetermined power supply voltage. 4. The recording head according to claim 1, wherein the heating element, the high-breakdown-voltage PMOS transistor, and the high-breakdown-voltage NMOS transistor are formed on a P-type silicon substrate. 5. The recording head according to claim 1, wherein the recording head is an inkjet recording head that performs recording by discharging ink. 6. The recording head according to claim 5 , wherein the ink is in contact with the heating element with an electrical insulating layer interposed therebetween, and the ink is heated by the heating element during a printing operation. 7. A recording apparatus using the recording head according to claim 1.