JPH11138775A - Element substrate, ink jet recording head, and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control malfunction owing to deterioration of a heater and a switch and a noise by a method wherein a plurality of switching elements provided corresponding to electricity-heat conversion elements in order to drive a plurality of electricity-heat conversion elements are connected in parallel, and switching timings of respective switching elements are differentiated. SOLUTION: When at first a signal is inputted at a timing of being at an IN terminal, C1-4 signals are respectively formed by a timing control circuit. In this case where the C1 signal is equal to an IN signal, the C2 signal becomes a signal delayed by a t1 content from the C1, the C4 becomes a signal delayed by a t3 content from the C1, a switch is ON and OFF controlled according to each timing, and a current IH flowing to a load becomes a stepping waveform under an ideal state. Consequently though high frequency components contained in a rise and a fall of the current are the same ones, their amplitudes can be lessened, the amplitude of overshoot or undershoot can be restrained, and consequently a ringing phenomenon can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element substrate used for a recording head, and more particularly to an element substrate having a switching circuit for suppressing ringing, an ink jet recording head, and an ink jet recording apparatus using the recording head.

In the present invention, "recording" means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern. Also means.

[0003] The present invention also provides a printer, a copier, a facsimile having a communication system, and a printer for recording on a recording medium such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, and the like. The present invention is applicable to an apparatus such as a word processor having a section, and an industrial recording apparatus combined with various processing apparatuses.

[0004]

2. Description of the Related Art Conventionally, a recording head mounted on a recording apparatus conforming to an ink-jet method for discharging ink from a discharge port by using heat has a plurality of electrothermal conversion elements (heaters) for generating thermal energy; A drive element for independently driving each electrothermal converter is provided. These electrothermal transducers and drive elements are described in, for example,
As shown in U.S. Pat. No. 85,594, they are formed on the same substrate by using a semiconductor process technique (the substrate on which these elements are formed is hereinafter referred to as an element substrate or a heater board).

FIG. 9 shows a drive equivalent circuit for one bit (one electrothermal transducer) used in such an ink jet head using an element substrate. In this equivalent circuit, the switch 2 (SQ) for driving the electrothermal transducer 1 is turned on at high speed,
In the case of the OFF control, a resonance circuit is formed by regulating inductances indicated by Lp1 and Lp2, parasitic capacitances indicated by Cp1 to Cp3, and a ringing phenomenon in which an overshoot or an undershoot of a signal appears.

Normally, the switch SQ is constituted by a diode, a bipolar transistor, an FET and the like, and the state of the above-mentioned ringing phenomenon is greatly affected by the switching characteristics of these switch elements.

For example, when a switch is formed using a MOS transistor such as an N-type MOSFET transistor (NMOS transistor), the size of the MOS transistor becomes extremely large in order to minimize the ON resistance. Therefore, the MOS transistor per bit may be as shown in FIG. 10, and the actual layout pattern is as shown in FIG.
The inventors have found that the source electrode 14 and the gate electrodes G1 to G4 made of polysilicon may be arranged in parallel. However, the current waveform of the switching signal in the case of driving a transistor having a layout in which the gate electrodes are connected in parallel as described above has a rising and falling steep waveform as shown in FIG. Become.

[0008]

However, since the element substrate having the transistor as described above is usually very small, it is difficult to provide a discrete component for suppressing ringing, and it is difficult to provide a parasitic inductance or a parasitic inductance. It is also difficult to reduce the parasitic capacitance. Therefore, it is difficult to prevent the above-described ringing, and there is a concern that deterioration due to stress on a heater (electrothermal converter) or a switch element due to ringing or malfunction due to noise generated by ringing may occur.

An object of the present invention is to provide an element substrate, an ink jet recording head, and an ink jet recording apparatus which are provided with means for suppressing a ringing phenomenon, thereby suppressing deterioration of a heater or a switch or malfunction due to noise by suppressing the ringing phenomenon. Is to do.

[0010]

The main structure of the element substrate according to the present invention for solving the above-mentioned problems includes a plurality of electrothermal transducers for generating heat for recording, and a plurality of electrothermal transducers. A plurality of switching means provided corresponding to the electrothermal conversion elements for driving the elements, wherein the switching means connects a plurality of switching elements in parallel, and performs switching of each switching element. The timing is different.

In order to solve the above-mentioned problems, the main structure of the ink jet recording head according to the present invention comprises a plurality of electrothermal transducers for generating heat for ejecting ink from ejection ports, and a plurality of electrothermal transducers. An element substrate having a plurality of switching means provided corresponding to the electrothermal conversion element for driving the conversion element; and a flow path provided at one end corresponding to the electrothermal conversion element and having one end communicating with the discharge port. And a switching means, wherein the switching means is configured such that a plurality of switching elements are connected in parallel, and switching timings of the respective switching elements are different.

According to another aspect of the present invention, there is provided an ink jet recording apparatus comprising: the above ink jet recording head; and a driving signal supply unit for supplying a driving signal for driving the recording head. .

(Operation) According to the above configuration, the switching timing of the plurality of switching elements constituting the switching means is shifted to reduce the amplitude of the high-frequency current component generated at the moment of switching, thereby preventing ringing. It is possible to suppress deterioration of the heater and the switch and malfunction due to noise.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings, but the "element substrate" used hereinafter does not indicate a simple substrate made of a silicon semiconductor, but includes elements, wirings, etc. 3 shows a substrate.

Further, "on the element substrate" refers not only to the top of the element substrate but also to the surface of the element substrate and the inside of the element substrate near the surface.

The term "built-in" according to the present invention does not mean that the individual elements are simply arranged on the substrate, but rather that each element is placed on the element substrate by a semiconductor circuit manufacturing process or the like. It is shown that it is integrally formed and manufactured.

In describing the present invention, first, the schematic configuration of the ink jet recording head of the present invention will be described with reference to FIG.

On the element base 20, heat is generated by receiving an electric signal, and electrothermal conversion elements (heaters) for discharging ink from the discharge ports 40 by bubbles generated by the heat are arranged in a plurality of rows. Are arranged. Each of the electrothermal transducers is provided with a wiring electrode 3 for supplying an electric signal for driving each electrothermal transducer, and one end of the wiring electrode is electrically connected to a switching means described later. ing.

A flow path 41 for supplying ink to a discharge port 40 provided at a position facing the electrothermal transducer is provided corresponding to each discharge port. Walls forming these discharge ports and flow paths are provided in the grooved member 101, and these grooved members 101 are attached to the element base 2.
A common liquid chamber 21 for supplying ink to the flow path 41 and a plurality of flow paths by connecting to zero is provided.

Hereinafter, the switching means of the present invention, which is formed together with the electrothermal conversion elements and the wiring electrodes in the element base 20 described above, will be described in each embodiment.

(First Embodiment) FIG. 2 is a block diagram showing the features of the circuit configuration on the element substrate of the present invention, and is a block diagram per bit for driving a heater (electrothermal conversion element). Reference numeral 1 denotes a heater S1 to 4 which is turned on / off. Reference numerals 1 to 4 denote switching elements constituting switching means provided corresponding to the heaters, 2 a timing control circuit, VH a terminal to which power is supplied, and IN a switch. Control input terminals C1 to C4 are switch control signals for S1 to S4, respectively. Next, the operation of the switching means will be described with reference to FIG. First, when a signal is input to the IN terminal at the timing shown in FIG. 3, signals C1 to C4 are generated by the timing control circuit. In this case, the signal of C1 is equal to the IN signal, and the signal of C2 is C1.
Becomes a signal delayed by ₁ minute t to, C4 is a signal delayed by t ₃ minutes to C1, each of the switches is ON · OFF controlled according to the timing, current IH flowing through the load is in the ideal state It has a step-like waveform as shown in FIG.

As a result, although the high-frequency components included in the rise and fall of the current are the same, the amplitude can be reduced, the amplitude of overshoot and undershoot is suppressed, and as a result, the ringing phenomenon can be suppressed. 4).

As a result, it is possible to suppress deterioration of the heater and the switching means and malfunction due to noise.

(Second Embodiment) FIG. 5 is a diagram showing another embodiment according to the present invention, wherein M1 to M4 are NMOSs and R1 which are switching elements constituting switching means.
3 to 3 are resistors, VH is a terminal to which power is supplied, and IN is a control input terminal. The resistors R1 to R3 may be formed using polysilicon as described later, but may be any thin film resistor that can be formed on the element substrate. Next, the operation will be briefly described. H from low level to IN terminal
When a high-level signal is input, a similar signal is given to the gate of M1, and M1 is turned on at substantially the same timing.
Turn off. However, the other M2-4 NMOSs have their gates supplied with signals delayed by a certain time due to their own gate capacitance and RC time constants due to the resistances of R1-3, and M
The current IL is turned ON / OFF in the order of 2, 3, and 4, and the current IL flows in the same manner as described above. be able to.

As a result, it is possible to suppress deterioration of the heater and the switching means and malfunction due to noise.

FIG. 6 is a diagram showing an example of an IC layout for realizing the switching means described in FIG. 11
Is a polysilicon as a gate electrode, 12 is a contact portion between a source / drain or diffusion layer and an aluminum electrode, 13 is an aluminum wiring as a drain electrode, and 14 is an aluminum wiring as a source electrode. G1 to G4 are gate portions of M1 to M4 shown in FIG.

In this embodiment, R1 to R3 in FIG.
4 is connected to a series to realize a circuit. Therefore, various RC circuits can be configured by changing the connection method of G1 to G3 corresponding to R1 to R3.

The actual operation will be described with reference to the layout shown in FIG. Since the polysilicon forming the gate is a resistor, an RC circuit also exists in G1 which is the gate of M1. This is true for all of M1 to M4, and as a result, R and C are expressed as distribution constants. Therefore, the current waveform IL shows a curve instead of a step-like shape. As a result, the high frequency component is suppressed, and the ringing is suppressed.

Further, since the capacity and resistance of the MOS transistor itself are used, the MOS transistor can be formed on the same heater board without increasing the area.

(Other Embodiments) FIG. 7 shows the structure of an ink jet recording head in which the element substrate 51 of the present invention is incorporated. The element substrate 51 is incorporated in a frame 54. On the element substrate, members constituting the above-described discharge ports and flow paths are attached. Further, a contact pad 53 for receiving an electric signal from the device side is provided, and the electric signal is supplied to the element substrate via the flexible cable 52.

According to such an ink jet head, since the element base itself has a structure for suppressing the ringing as described above, a small-sized head which does not easily malfunction due to ringing and has a long life is provided. can do.

FIG. 8 is a schematic view of an ink jet recording apparatus IJRA to which the ink jet head of the present invention is applied.
The carriage HC that engages with the groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with the forward and reverse rotation of the drive motor 5013 has a pin (not shown), It is reciprocated in the directions a and b. Reference numeral 5002 denotes a paper pressing plate, which presses the paper against a platen 5000 serving as a recording medium transport unit in the carriage moving direction. Reference numerals 5007 and 5008 denote home position detection means for confirming the presence of the carriage lever 5006 in this area by photocouplers and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the print head. Reference numeral 5015 denotes suction means that suctions the inside of the cap, and performs suction recovery of the print head through the opening 5023 in the cap. 5017 is a cleaning blade,
Reference numeral 5019 denotes a member that enables the blade to move in the front-rear direction, and these members are supported by the 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. or,
Reference numeral 5012 denotes a lever for starting suction for suction recovery. The lever 5012 moves with the movement of the cam 5020 that engages with the carriage, and the movement of the driving force from the drive motor is controlled by known transmission means such as clutch switching. .

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 home position side area. Any desired operation can be applied to this example. Each of the configurations described above is an excellent invention when viewed alone or in combination, and shows preferred configuration examples for the present invention.

The apparatus has a drive signal supply means for driving the electrothermal transducer.

In the ink jet recording apparatus of the present invention, since the above-described ink jet recording head is mounted, a recording operation can be performed faithfully without giving a malfunction to a given signal. Further, since the life of the head itself is long, a recording apparatus having a long life and low running cost can be provided.

[0036]

As described above, according to the first aspect of the present invention, since a switching element constituted by a plurality of switching elements and having different switching timings is provided on the element substrate, ringing is prevented. This makes it possible to provide an element substrate, an ink jet recording head, and an ink jet recording apparatus in which a ringing phenomenon is suppressed to suppress malfunctions due to deterioration of heaters and switches and noise.

In a configuration in which polysilicon is used as a resistor for a gate electrode of a MOS transistor serving as a switch element, timing control can be performed by forming an RC time constant by combining gate capacitances, thereby increasing the area in particular. A configuration in which the switching timings are different on the same element substrate can be created without performing the same, and the miniaturization of the head can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ink jet recording head of the present invention.

FIG. 2 is a diagram showing an example of a circuit configuration on an element substrate of the present invention.

FIG. 3 is a diagram for explaining an operation of a switching unit;

FIG. 4 is a diagram for explaining rise and fall of current according to the present invention;

FIG. 5 is a diagram showing another example of the circuit configuration on the element substrate of the present invention.

FIG. 6 is a diagram showing an example of an IC layout according to the present invention.

FIG. 7 is a configuration diagram of an ink jet recording head of the present invention.

FIG. 8 is a schematic view of an ink jet recording apparatus according to the present invention.

FIG. 9 is a diagram showing an example of a circuit configuration on a conventional element substrate.

FIG. 10 is a diagram illustrating a circuit configuration of a switching unit according to a background art that is not known.

FIG. 11 is a diagram illustrating an example of an IC layout of a switching unit according to a background art that is not known.

FIG. 12 is a diagram for explaining a current waveform when ringing occurs.

[Explanation of symbols]

 VH power supply terminal IN input signal terminal S0-4 switch M1-4 NMOS transistor C1-4 control terminal (signal) of S1-4 R1-3 resistance Lp1, parasitic inductance Cp1,2,3 parasitic capacitance 1 electrothermal conversion element ( Heater) 2 Timing control circuit 51 Heater board 52 TAB tape 53 Terminal 54 Housing

Claims (17)

[Claims] 1. A plurality of electrothermal transducers for generating heat for performing recording, and a plurality of switching means provided corresponding to the electrothermal transducers for driving the plurality of electrothermal transducers. Wherein the switching means connects a plurality of switching elements in parallel, and the switching timings of the respective switching elements are different from each other. 2. The element substrate according to claim 1, wherein said switching element comprises a MOS transistor. 3. The device substrate according to claim 2, wherein a gate electrode of said MOS transistor is made of polysilicon. 4. The element substrate according to claim 1, wherein said switching element comprises a bipolar transistor. 5. The element substrate according to claim 1, wherein said switching means has a delay circuit for delaying a drive timing of each of said plurality of switching elements by a predetermined time. 6. The element substrate according to claim 5, wherein said delay circuit is a timing control circuit. 7. The element substrate according to claim 5, wherein said delay circuit is constituted by an electric resistance disposed between gate electrodes of said switching element. 8. The element substrate according to claim 7, wherein said electric resistance constitutes said switching element and utilizes electric resistance of a gate electrode connected to each switching element. 9. A plurality of electrothermal transducers for generating heat for ejecting ink from a discharge port, and a plurality of electrothermal transducers provided to drive the plurality of electrothermal transducers. An ink jet recording head comprising: an element substrate having a plurality of switching means; and a flow path provided corresponding to the electrothermal transducer and having one end communicating with the ejection port. The switching means includes a plurality of switching elements. An ink jet recording head which is connected in parallel and is configured such that switching timing of each switching element is different. 10. The ink jet recording head according to claim 9, wherein said switching element is constituted by a MOS transistor. 11. The ink jet recording head according to claim 10, wherein a gate electrode of said MOS transistor is made of polysilicon. 12. The ink jet recording head according to claim 9, wherein said switching element is constituted by a bipolar transistor. 13. The ink jet recording head according to claim 9, wherein said switching means has a delay circuit for delaying a drive timing of each of said plurality of switching elements by a predetermined time. 14. The ink jet recording head according to claim 13, wherein said delay circuit is a timing control circuit. 15. The ink jet recording head according to claim 13, wherein said delay circuit is constituted by an electric resistor arranged between gate electrodes of said switching element. 16. The ink jet recording head according to claim 15, wherein said electric resistance constitutes said switching element and utilizes electric resistance of a gate electrode connected to each switching element. 17. An ink jet recording apparatus comprising: the ink jet recording head according to claim 9; and a driving signal supply unit that supplies a driving signal for driving the ink jet recording head.