JPH0348034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device, and more specifically, to an inkjet recording device, the liquid is ejected as small droplets from an orifice connected to a chamber containing the introduced recording liquid, and the liquid is deposited on a recording material to perform recording. The present invention relates to a recording device that performs. In contrast to the impact recording method represented by typewriters, which are relatively simple recording devices, the non-impact recording method has the advantage that the noise generated during recording is extremely small to the extent that it can be ignored. has been attracting attention recently. Among these, the inkjet recording method is recognized as an extremely effective recording method, as it is particularly capable of high-speed recording and can perform recording on plain paper without requiring any special fixing process. Various methods have been proposed for this inkjet recording method, and some have been commercialized with various improvements, and efforts are still being made to put them into practical use. There are some things.

In short, the inkjet recording method is a method in which droplets of a recording liquid called ink are ejected from a fine orifice and attached to a recording member to perform recording. The inkjet recording method is roughly divided into several methods based on the method of generating recording liquid droplets and the control method for controlling the flight direction of the generated recording droplets.

One of them is one that uses a piezoelectric element and one that uses a high voltage. Furthermore, as a method that does not use high voltage, Japanese Patent Application Laid-Open No. 132036/1984 discloses a technique that utilizes the bursting of bubbles by applying thermal energy to ink. However, there is no disclosure at all about its practicality as a recording device, especially about high-speed recording suitable for multi-nozzle design.

On the other hand, as a recording method that uses thermal energy,
The so-called thermal recording method in which a conventional thermal head is pressed against thermal paper to develop color (e.g.,
144241 and Japanese Patent Application Laid-open No. 144241 and JP-A-54-21854), however, since the time required for chemical changes to develop color on thermal paper is relatively long, even higher speed recording is desired.

The present invention provides a recording method using a new inkjet recording head which is different in principle and idea from these several methods.

That is, the present applicant has a large number of thermal energy generating means provided in a liquid chamber equipped with a discharge port, corresponding to a large number of discharge ports, and the large number of thermal energy generating means generates heat in response to a drive signal. has proposed a recording head that performs recording by forming flying droplets by forming bubbles in the liquid using thermal energy and ejecting the liquid from the ejection port based on the pressure of the bubbles. Application No. 53-101189, etc.) According to this recording head, the ejection cycle can be stabilized and the ejection frequency can be increased, and since the structure is extremely simple and microfabrication can be easily performed, the recording head itself can be significantly miniaturized. Furthermore, due to its structural simplicity and ease of processing, it has remarkable features such as being able to extremely easily realize multi-nozzle formation, which is essential for high-speed recording.

However, a recording method capable of achieving high-speed recording and high-density recording by suitably driving the novel recording head has not yet been proposed.

Therefore, an object of the present invention is to provide a recording method suitable for performing high-density recording and high-speed recording using a recording head that discharges ink from a large number of discharge ports based on the formation of bubbles by thermal energy. .

The present invention will be specifically explained in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram for explaining the principle of recording by the recording head of the present invention.

In the recording liquid chamber W, whose tip is formed into a nozzle, which constitutes the recording head, an orifice OF
Pressure P is applied to the extent that the recording liquid IK is not ejected, and the recording liquid IK is supplied. Now, in a portion of width △l in the liquid chamber W1 at a distance of l from the orifice OF,
When electric energy (driving pulse) is applied to the heating element H1, the temperature of the heating element H1 starts to rise. When the heating element H1 reaches a temperature higher than the vaporization temperature of the recording liquid in the chamber W1, bubbles B are generated on the heating element H1. The bubbles B grow as the temperature of the heating element H1 further increases, and their volume increases rapidly. As a result, the pressure inside the liquid chamber W1 increases rapidly, and the recording liquid that was present in Δl by the volume increased by the bubble B suddenly moves in the direction of the orifice OF and in the opposite direction to where the pressure P is applied. Moving. l in liquid chamber W
Some of the recording liquid that was present in the orifice OF
It is discharged from. The ejected recording liquid becomes a liquid column and is connected to the orifice OF, and the air bubbles B
The liquid column that comes out of the orifice OF stops growing when it reaches its maximum, but the tip of the liquid column has accumulated the kinetic energy that has been applied up to this point. Further, when the bubble B collides with the ceiling surface of the Δl portion of the liquid chamber W1, the force changes its direction in the longitudinal direction on the orifice side, and the droplet driving force is further increased.

By cutting off the driving pulse applied to the heating element H1, the temperature of the heating element H1 is radiated to the substrate side and lowered. The bubble B gradually cools down due to the temperature drop, and its volume begins to shrink a little later than when the driving pulse ends. As the volume of the bubble B shrinks, recording liquid is retained in the Δl portion from the orifice OF side and from the direction where the pressure P is applied. As a result, in order to replenish the volume of the recording liquid present in the l portion drawn back to the Δl portion, the recording liquid in the portion of the liquid column growing from the orifice OF near the orifice OF is drawn back to the chamber W1. It will be returned. As a result, the directions of the kinetic energy at the tip of the liquid column and the kinetic energy of the liquid column near the orifice OF are reversed, and the tip of the liquid column separates, becomes a recording droplet ID, flies toward the recording member PP, and flies toward the recording member PP. Adhere in place on the PP. When the bubble B on the heating element H1 gradually disappears due to cooling, the volume of recording liquid drawn back into the chamber W1 is smaller than the volume of the liquid chamber W1, causing the liquid level (meniscus) to retreat from the orifice OF surface.
A pressure P is always present in the recording liquid, and the bubble B gradually contracts due to the thermal inertia of the heat pulse (T in FIG. 3), and the meniscus gradually returns to its original state.
Further, thermal energy can be applied to the recording liquid IK in a temporally discontinuous manner, and the applied thermal energy can carry recorded information. In other words, the heating element generates heat in pulses according to the recording information signal, so a change in state occurs in the recording liquid and the orifice
All of the droplet IDs ejected from the OF carry recording information, and therefore all of them are recorded on the recording material.
Desired recording is performed by adhering to the PP. The size of the droplet ID discharged from the orifice OF is determined by the amount of thermal energy applied, the width of the portion △l that is affected by the thermal energy, the inner diameter d of the liquid chamber W, and the orifice.
It depends on the device conditions such as the distance l from OF to the heating element H1, the pressure P applied to the liquid IK, or the physical property values of the material such as the specific heat, thermal conductivity, coefficient of thermal expansion, and viscosity of the liquid IK. In addition, a laser beam can be used instead of the heating element mentioned above.
Even when LZP is instantaneously irradiated, bubbles B are similarly generated, disappear, and a single droplet is ejected. In this case △l
Part H1 can be used as a reflection plate, a heat storage plate, or other purposes to make heat generation by the laser pulse LZP more efficient, but is not necessarily required.

FIG. 2 t0 to t9 are schematic diagrams showing the ejection process of recording liquid (hereinafter referred to as ink), in which an orifice OF, an ink chamber W, and a heating element H1 are shown, and ink IK is supplied from an arrow P. The interface (liquid level) between the ink IK and the outside air is shown in IM. Let B be the bubbles generated on the heating element H1. FIG. 3A shows an example E of drive pulses, and t0 to t9 indicate times corresponding to t0 to t9 in FIG. 2. T in FIG. 3B is a diagram showing the temperature change of the heating element H1, and FIG. 3C is a diagram showing the volume change of the bubble B. At t0, a state before ejection is shown, and at tp between t0 and t1, a driving pulse E is applied to the heating element H1. As shown at tp, the temperature of the heating element H1 starts to rise at the same time as the driving pulse E is applied. At t1, the temperature of the heating element exceeds the vaporization temperature of the ink, and bubbles B begin to form and the liquid level IM
shows a state in which the ink IK swells in proportion to the pressure exerted on the ink IK by the bubble B from the orifice surface.
At t2, the bubble B grows further and the liquid level IM further swells. At t3, the driving pulse E falls as shown in FIG. 3A, and when the temperature of the heating element H1 reaches the maximum as shown in FIG.
grows like a film and the liquid surface IM swells. t4 is the third
As shown in Figure B, the heating element temperature T has begun to fall, but as shown in Figure 3C, the volume of the bubble B has reached its highest level, and the liquid level IM has further expanded. At t5, the bubble volume B begins to shrink. Therefore, the ink IK is drawn into the ink chamber W by the amount that the air bubbles B contract with respect to the liquid surface IM that bulges out from the orifice OF. As a result, the liquid level IM is constricted at the part indicated by the arrow Q. t6
Then, the contraction of bubble B further progresses, and the droplet ID and liquid level
Separation occurs between IM′ and IM′. At t7, the droplet ID is ejected and flies, the bubble B further contracts, and the liquid level IM' further approaches the orifice OF surface. At t8, the bubble B is about to disappear, the liquid level IM further retreats, and it is drawn into the inner surface from the orifice OF. t9 is ink
This indicates that IK has been supplied and the state has returned to t0.

From the above explanation, the shape of the drive pulse applied to the heating element H1 is an important element for stable ejection of the recording liquid IK.
Furthermore, bubble contraction is an important factor when recording droplets are separated, and this contraction can be easily controlled by the shape of the driving pulse. Also,
The droplet ejection speed can be similarly controlled by the drive pulse shape. Furthermore, the droplet ejection frequency can also be increased by changing the drive pulse shape.

4A, B, and C show various driving pulse waveforms E applied to the heating element H1, temperature changes T of the heating element H1, and volume changes B of bubbles in response thereto.

Ink droplets are suitably ejected with any of these drive pulse waveforms. The waveform at a is an extremely effective pulse waveform that does not require a high resistor for the CR discharge circuit in the piezo drive system and does not require special specifications for the drive circuit. In the waveform b, preheat bias heating is performed before the pulse rises to shorten the pulse width during droplet ejection. Discharge using this waveform caused bubbles to rise quickly and was effective in improving the discharge speed and response frequency. Furthermore, since preheating is performed only during recording, it is possible to prevent the recording liquid from becoming too warm and causing problems.

The waveform in c is one in which bias heating is performed at the falling edge of the pulse, so that the meniscus can be retreated more gradually after droplet separation. This waveform prevented excessive intake of air into the orifice liquid chamber after ejection, and smooth ejection was obtained during the next recording. Also in this case, since bias heating is performed only during recording, the bubbles completely disappear, which is effective for the next recording. The waveform in d is for smooth droplet separation and gradual cooling to prevent the liquid level from receding too much. It can be done gradually and is effective. e is an effective pulse waveform that is a composite of the waveforms b and d described above.

As described above, the present invention is capable of stably ejecting droplets by controlling the rise and fall of the drive pulse, and in particular, the drive by heating a heater above the vaporization temperature of the recording liquid. It includes the rising part of the pulse, the falling part of the drive pulse for cooling the heater to smoothly separate the droplets ejected from the orifice surface, and the falling part of the driving pulse that cools the heater to smoothly separate the droplets ejected from the orifice surface. ) is effective for stable dispensing.

In any of the above cases, it is only necessary to control the drive pulse, and there is no need for external high-resistance elements. In particular, cooling of the heating element and contraction of bubbles proceed extremely gradually due to the thermal inertia of the heat pulse, so It is possible to prevent accidents in which droplets are not ejected even when the next print command pulse is input due to excessive air entering from the orifice due to the receding of the liquid level. It is determined by the pulse width S and the pulse height L. In particular, a is preferable in terms of LSI functionality. Also, the laser pulse has a shape similar to a,
The above-mentioned thermal pulses, thermal inertia, etc. are also phenomena that occur in the laser head as well. In addition, it is extremely easy to control the intensity of the laser beam, and it is possible to generate laser beams with similar waveforms from be to e. It is also easy to control the amount of heat generated, heat pulses, and bubbles using the laser beam. I was able to realize this. Therefore, terms such as heating element, heat pulse, thermal inertia, etc. used below shall include laser light, infrared light, and other heat generating means.

FIG. 5 is an exploded perspective view of a circuit for explaining an example of the head configuration. In Figure 5, the board SSI
Heating elements H1 to H7, a digit electrode D1, and selection electrodes P1 to P7 are formed on the surface of. The heating elements H1 to H7 have the same area and the same resistance value, and 1
One heating element corresponds to one ink liquid chamber. The plate GL1 is provided with an ink supply port IS for supplying ink, and minute grooves M1 to M7 for forming the liquid chambers and a common ink supply groove ND for supplying ink to each groove are formed. be done. Further, at the ink discharge end of the grooved plate GL1, an orifice plate (not shown) is provided as necessary. The grooved plate GL1 is made of glass, and has a common ink supply groove ND formed by etching, and a plurality of grooves M1 that also serve as liquid chambers.
~M7 is formed. Each groove M1 to M7 is board SK
1 to form a plurality of liquid chambers. Therefore, the grooves M1 to M7 are joined on each heating element in a corresponding manner. Each of the heating elements H1 to H7 is selected and generates heat depending on the presence or absence of an external input signal. The energy applied when generating heat varies depending on the level of the input signal. Also, without attaching a heating element to this board SS1, the board SS1 is used simply as an ink receiver, and as shown in the figure, the carriage guide CG
The laser head LZH is slidably attached to the plate GL1 and moved intermittently or continuously while selectively irradiating each groove with a laser pulse LZP for a unit time from above the plate GL1. Alternatively, LZH may be fixedly provided for all heating elements. A detailed example of the substrate SS1 having a heating element is shown in FIGS. 6A and 6B. For example, on an alumina substrate AM, there is a heat storage layer SO made of SiO ₂ (several microns thick), a heating resistor layer H made of ZrB ₂ (thickness 800 Å), and an aluminum electrode layer AL (thickness
5000Å) and then selectively etched the width.
Heat generating parts H1, H2, H3, etc., each having a length of 60 μm and a length of 75 μm were formed. Also, by etching, the selection electrodes P1,
P2, P3, etc. and the digit electrode D1 were formed. Furthermore, as shown in FIG. 6B, this heating element H1 etc. and the electrode layer
A protective layer K (thickness 1 μm) made of SiO ₂ is further formed on the AL.
are layered.

FIG. 7 shows another example having basically the same configuration as the recording head described above.
Heat generating elements H1 to H7 and selection electrodes 1l1 to 1l7 are formed on the surface of SS1. The plurality of heating elements H1 to H7 have the same area and the same resistance value,
One heating element corresponds to one liquid chamber.
The substrate SS1 is covered with a plate GL1 having grooves M1 to M7 cut therein, and forms a plurality of liquid chambers at the joint with the substrate SS1. The plate GL1 is provided with an ink supply chamber ND that supplies ink.
Further, an inlet IS is provided for introducing ink from an ink tank (not shown).

The difference from FIG. 5 is the arrangement of the digit electrodes.
When the heating elements H1 to H7 are driven at the same time, a considerable current flows through the digit electrode D1 in FIG. 5, and it is conceivable that the digit electrode D1 may be destroyed. However, the digit electrode D1 in FIG.
If it is divided into seven parts as shown in ~D, the above-mentioned difficulty can be solved.

FIG. 8 is a wiring diagram for time division drive in the device shown in FIG. 7, and FIG. 9 is a waveform diagram for explaining its operation. One block is formed by the power generating elements 1H1 to 1H32, and a total of 1792 heating elements 1H1 to 5 are formed in 56 blocks.
There are 6H32, and each heating element has 56 blocks with diodes 1d1 to 1d32 as one block array DA1, a total of 1792 diodes 1d1 to 5.
Connected to 6d32. Each diode is connected to image information terminals P1 to P32 through connectors 1P1 to 56P32. heating element 1
The other end of H1-1H32 is Kennectar 1D1-1D
32 to the scanning signal terminal D1.
Heating elements 2H1 to 2H32,...56H1 to 56H
32 are similarly scanning signal terminals D2 to D56, respectively.
It is connected to the. On the aforementioned substrate SS1 are heating elements 1H1 to 1H32 and diodes 1d1 to 1d3.
2 and connector lead wires 1l1 to 1l32 are wired. On the other boards, heating elements, diodes, and lead wires are similarly separated into 56 cassettes each block. In this case, as shown in FIG. 9, each block is time-divisionally driven with a duty of 1/56 to generate bubbles in each liquid chamber and cause the droplets to fly. As shown in Figure 9, the first digit BD1, where image information P1 etc. is sparsely generated, does not require much power to drive simultaneously, but when driving 32 nozzles simultaneously in the second digit BD2, This results in considerable power consumption.

FIG. 10 shows an example of a circuit that solves this problem. In the figure, PTG is an image information generator, DPG is a scanning signal generator, RGC is a signal generator consisting of a ring counter or ROM, etc., and only four heating elements, for example H1, H9, H17, and H25, are driven at the same time. , at the next timing, 4 more for example H2, H1
This is a circuit for driving 0, H18, and H26. That is, AND gates A1 to A32 are provided, and only four of every eight ink jet nozzles are driven at the same time. With this configuration, the electric power required to simultaneously drive 32 nozzles becomes 1/8 compared to the example shown in FIG. 8. That is, as shown in Fig. 11, every 8 of the 32 heating elements are driven to generate air bubbles, causing droplets to fly, first printing 4 dots, and then printing the next dot. 4 dots are printed and this process is repeated 8 times to complete 32 dots of line printing. This greatly improves print quality. That is, for example, when liquid droplets are simultaneously flown from three adjacent nozzles, it is possible to eliminate problems such as the adjacent droplets connecting with each other and deteriorating print quality or reducing cooling efficiency after heat generation. . This example circuit is used for the recording head of FIGS. 5 and 6A.

However, even in these examples, the electrode D1 on the orifice side is a digit electrode, that is, an electrode for selecting a groove for each block, etc., so it is limited to a predetermined size and can be extended to an arbitrary length to lower the resistance value. I can't.

Therefore, excessive current cannot flow, and D
The width and height of 1st class are quite necessary. In this case, the distance between the orifice and the heating element must be as shown in FIG. 6B, and the flying efficiency of droplets due to the application of thermal energy is reduced.

Figure 12 shows an example of a circuit that solves this problem, using a transistor array TA instead of a diode array DA, and using a large number of heating elements 1H1 to 56H3.
Each end of 2 is connected to a separate transistor 1T1 to 56T.
32 collectors, and the other ends of those heating elements are connected in common. In addition, the emitter terminals of the transistors in each block are connected to a common switching element MD.
1 to MD56, and transistors 1T1 to 1T32, ...56T1 to 56T32 of each block.
The bases of those located at relative positions are connected to common image information input terminals P1 to P32.

For example, in order to energize the heating element 56H32, close the switching element MD56 and switch MD55 to MD1.
is opened and image information is applied to terminal P1. This driving voltage causes the transistor 56T32 to conduct.
HV-56H32-56T32-MD56-Electrify the heat generating 56H32 through the earth EA.

At this time, the collectors and emitters of the transistors 56T1 to 56T31 are biased in the forward direction, but since there is no image information input signal to P2 to P32, 56T1 to 56T31 do not become conductive.
Therefore, the image signal supplied from P1 flows only to transistor 56T32.

Switching elements MD1 to MD5 as above
By selectively combining the closing of 6 and the voltage application to the image information input terminals P1 to P32, it is possible to selectively energize and drive the intended heating element.

FIG. 13 is an example of a drive circuit in which a common base type transistor array is used instead of the common emitter type as shown in FIG. 12. This utilizes the current amplification factors of individual transistors in the array configuration to reduce the current values on both the individual emitters on the array and the external lead line of the common base. In other words, the emitters through which a relatively large current flows are drawn out individually, and the base through which a relatively small current flows is shared, thereby reducing the current value on the external lead wires. It is possible to prevent a large current from flowing only through the wire. Therefore, there is an advantage that the burden on the drive circuit is reduced, and at the same time, there is no need to pay special attention to the large current value when drawing out the bonding wires from the array.

Figure 14 shows a field effect transistor (FET)
This is an example in which the drive power is reduced, and at the same time, the device features such as short storage time and short switching time, high speed, and simplification of the drive circuit due to its transfer characteristics. can be measured.

Furthermore, it is easy to understand that FIG. 14 uses a common-gate matrix, similar to FIG. 12 and FIG. 13. Further, the common emitter driving transistor in FIG. 12 may be constructed by a bipolar transistor. Furthermore, in Figures 12 to 14, PNP transistors or P-channel FETs are used instead of NPN transistors or N-channel FETs.
It is also clear that the power supply polarity can be reversed by using channel FETs. Furthermore, according to these embodiments, it is not necessary to return each digit electrode as shown in FIG. 7, and there is no need to use the digit electrode D1 as shown in FIGS. 5 and 6A, which is extremely preferable.

That is, if the above-mentioned heating element and lead electrode are formed on a conductive substrate (for example, metal or silicon) via an insulating film, and the HV shown in Fig. 12 is connected to the conductive substrate, the resistance will be extremely low and heat will be generated. It becomes possible to keep the distance between the body and the orifice sufficiently short. Specifically, for example, an insulating film SiO ₂ is deposited on a Cu substrate.
After laminating about 3 μm by sputtering and removing SiO ₂ only near the orifice by etching, heat generating elements H1, H2, etc. and electrodes P1, P
2 etc. are formed by sputtering, and a predetermined pattern is formed by etching. At this time, the electrode on the orifice side is brought into conduction with the substrate, so the substrate itself may be used as the HV electrode. Further, the digit selection electrode D1 etc. shown in FIG.
It is desirable that the voltage drop is sufficiently small regardless of the number of energized P32, so it is preferable to form it thick and with low resistance.

FIG. 15 is a detailed diagram of a recording head using the driving methods shown in FIGS. 12, 13, 14, etc.
A conductive substrate 1C in which H2, . . . Hi, .
The grooved plate GL1 provided with a heating element is connected to the heating element as described above.
They are joined and integrated so that the long grooves are in corresponding positions.

The insulating layer I1 not only has the purpose of electrical insulation, but also functions as a heat storage layer for controlling the flow rate of heat generated by the heating element.

And heating elements 1H1~ formed on the substrate 1C
1H32 further includes selection electrodes 1l1 to 1li to 1l32 for selectively applying an image signal to the heating element.
and a common electrode L are formed as shown in FIGS. 15 and 16. This common electrode L is connected to the heating elements 1H1 to 1H
Commonly provided for all 32. Each electrode is provided with the aforementioned transistor array TA in the middle of drawing out the electrode.
is connected. Further, at least one of the digit electrodes D1 to D56 and selection electrodes P1 to P32 as energizing means for applying a digit signal are formed on the insulating layer 11 on the substrate 1. FIG. 20 shows a cross-sectional view of the configuration shown in FIG. 19.

As is clear from this figure, the heating element Hi is on the board 1C.
The conductive layer Pi, li', etc., which is formed on top of the insulating layer I1 and which becomes the common electrode L for applying the power supply voltage HV to the heating element and the conductive layers Pi and li' which become the selection electrodes, is formed on the insulating layer I1.
1.

FIG. 17 shows another embodiment of the recording head of this embodiment, in which a conductive layer 1C' is formed on an insulating substrate I1', and this is used, for example, as a conductive layer for the power supply potential HV, that is, a common electrode. , also heatsink HS
This is an example of using as an electrode for ground potential EA.
Also, connect the ground potential EA to the conductive layer 1C or 1C',
It is clear from FIG. 12 etc. that the power supply potential HV may be introduced from elsewhere or may be introduced into the heat sink HS.

Materials for the conductive layer include metals such as Al and Au, and materials for the heating element include ZrB ₂ , HfB ₂ , Ta ₂ N, W,
Ni-Cr, thick film resistor (Pd-Ag, Ru, etc.)
A common resistor such as SnD ₂ is used.

In the case of the embodiment shown in FIG. 16, various metals, crystalline Si substrates, etc. are preferably used as the substrate IC.

In addition, a thin insulating protective layer is provided on the surfaces of the conductive layers Pi, Li, Di, etc. and the heating layer Hi, etc., in order to prevent chemical reactions, current leakage, mechanical friction, etc. due to contact with the recording liquid. It is also desirable to do so. Further, for the connection between the common electrode L and the conductive plate 1C, a through hole IB as shown in FIG. 18 may be used, or
In order to form a large number of selective electrodes within one plane with more margin, it is also effective to alternately provide multiple layers of conductive layers and insulating layers that serve as electrodes. Furthermore, for ease of attachment and detachment, it is preferable to connect the connectors using connector contact pieces Ci and CH.

[Example] A recording head was prepared using a substrate having the structure shown in FIG. However, substrate IC: wafer (0.6 mm thick) made by epitaxially growing low-resistance silicon on a high-resistance silicon wafer, insulating layer I1: SiO ₂ (5μ
thickness), a resistive layer (Hi); ZrB ₂ (thickness: 800 Å), and a conductive layer (electrodes L, Pi, D ₁ , etc.); Al (1000 Å). Thereafter, a heating element with a width of 40 μm, a length of 100 μm, and a pitch of 120 μm and a common electrode and selection electrode in a predetermined pattern were created by photoetching.

Note that the common electrode has a common structure for 32 heating elements.

On top of this, _two layers of SiO (thickness 1 μm) are further laminated,
This is a substrate structure having a heating element.

On the other hand, a grooved pattern with a width of 40 μm and a depth of 40 μm was formed at a pitch of 120 μm on a glass plate (thickness: 1 mm) to produce a grooved plate GL1.

Next, the aforementioned substrate and the grooved plate were bonded together to form a recording head.

Figure 19 is an example of Figure 12 divided into blocks for each 32 heating elements.FP1 is an ink supply pipe that can be attached to and detached from GL1, and when removed, the board SS1
comes off from the main body.

FIG. 20 is a sectional view showing an example of a connection configuration between the ink supply pipe FP1 and the ink introduction port IS. Packing into the inlet IS drilled in plate GL1
FH has been inserted and is undergoing O-ring OR. O
Ring OR is held on flange FG. The flange FG is inserted into the ink supply pipe FP1, and the ink supply pipe FP1 is equipped with a packing FH and a spring SP1 that presses the flange FG to prevent ink from leaking between the connectors. This figure shows an example of how to smoothly attach and detach the ink supply pipe FP1 when the ink supply pipe is made into a cassette according to the present invention.
Although the connection method of FP1 is not limited, the ink supply pipe can be connected using crimping or other means as shown in this figure.
It is desirable to connect FP1. FL is a filter.

As described above, various improvements have been made by forming a multi-discharge nozzle array into a cassette and combining a plurality of these cassetted nozzle arrays.In particular, a heating element and lead electrodes are attached to a small substrate 1C formed into a cassette. , vacuum thin film forming equipment for forming protective films and insulating films, and masks and mask aligners necessary for creating heating elements and lead electrode patterns can be easily made using commercially available small equipment. has. Also pipe FP
If 1 has flexibility, it can be easily bent during attachment and detachment, so attachment and detachment operations can be performed without any trouble.

Furthermore, this cassette may have a form not only as shown in FIG. 19 but also as shown in FIG. 23, which will be described later, and is not particularly limited to this form. In other words, reducing the size of the heating element substrate improves its productivity, making it easier to replace malfunctioning nozzles by making it into a cassette, and eliminating various risks that occur when connecting to the transistor array, improving yield. It has a number of features such as being extremely effective in improving Furthermore, manufacturing errors for each block can be made uniform by adjusting the amplitude, time width, etc. of the drive pulse.

FIG. 21 shows the above-mentioned cassette type inkjet recording head blocks fully assembled and arranged alternately above and below one common plate. In the figure, odd-numbered blocks GL1, GL3, . . . GL _o-1 are connected to the upper surface of the heat sink HS, and even-numbered blocks GL2, GL4 _, .
Ink IK is supplied to each block by an ink tank IT, an ink pipe IP, pipes OP and EP for common distribution to each block, and pipes FP1 to FPn for distribution to each block. As shown in an example in FIG. 20, the pipes FP1 to FPn connected to each block can be attached to and detached from the blocks and have flexibility, so that the pipes FP1 to FPn can be conveniently bent when being attached or detached.

TA1 to TAn are transistor arrays which are the same as those described above, and are connected to respective selection electrodes 111 to 1132, D1 to Dn, etc. on the substrates with heating elements 1C to nC. This zigzag arrangement is preferable because the distance Q between the orifices OF1, OF2 and OF32 is the same on the upper and lower sides as shown in FIG.

FIG. 23 shows another example of a cassette block, in which four blocks of lead wires P1 to P32, D1, etc. are formed on a conductive substrate 1C, and a transistor array TA1 to TA7 is connected to the center of each lead wire. There is. The aforementioned transistors and switching elements are formed in each of transistor arrays TA1 to TA7. In this cassette, the 32 grooves of the plate GL constitute one block, and blanks BL1, BL2, and BL3 are provided between each block. This requires at least 33 lead wires as mentioned above to drive 32 heating elements independently, and since various other functions are housed in the array, the chip volume also becomes large. If the A4 size full multi-nozzle array is arranged densely without any blanks, the transistor array TA
When connecting TA1 to TA7, the pitch of the Honda patch becomes extremely small, making it impossible to use commercially available wire bonders. Furthermore, the joining interval between each cassette must be at least equal to the groove interval, which makes processing very difficult. So the second
If blanks BL1 to BL3 are provided as shown in FIG. 3, the transistor array, for example TA7, can be connected using the blank length B. Since these blanks BL1 to BL3 are the parts to which no information is given when recording, they are attached to the front and back sides of the metal plate HS using jigs in the same manner as described above, as shown in Figure 24, to supplement each other's blanks. .

The example in Figure 24 is an A4 size full multi 8 pieces/mm.
This is an example. Conductive substrates 1C to 14C with 32 heating elements on both sides of a metal plate HS that also serves as a heat sink
14 sheets of 7 sheets each are bonded, and 1 substrate with heating element
Plates GL1 to GL14, each having the aforementioned 32 grooves, are joined onto C to 14C, respectively.
14 ink introduction pipes OP1 to OP28 are connected to each plate GL1 to GL14, two each on both sides, and each ink introduction pipe is connected to an ink tank.
Connected to IT. Connected through ink supply pipes OP and EP. The conductive substrates 1C to 14C with heating elements joined to the metal plate HS are housed in a case KA with a built-in connector. Furthermore, it is of course preferable to connect the above-mentioned HV or EA to a metal plate HS that also serves as a heat sink.

As mentioned above, this embodiment is extremely suitable as a countermeasure against large currents, and, for example, it is possible to minimize the width of the common electrode L, so the orifice part and the heat generating part can be brought close to each other in a suitable relationship, and the thermal ink cartridge It has an extremely high efficiency and simple configuration as an edge head.

As explained above, according to the present invention, when performing high-density and high-speed recording using a recording head that ejects ink from a plurality of ejection ports based on the formation of bubbles by thermal energy, a large number of Even if thermal energy generation means for ink ejection are arranged,
Since the drive is performed in units of blocks consisting of predetermined thermal energy generating means, the driving time can be shortened, and since time-division driving is performed in units of blocks, it is possible to reduce power consumption during driving.

[Brief explanation of drawings]

Figures 1, 2, and 3 are diagrams explaining the principle of the recording head, Figure 4 is a diagram of its various driving waveforms, Figure 5 is a diagram showing an example of the configuration of the recording head, and Figures 6A and 6B are partially enlarged views and cross sections thereof. 7 is an example of another head, FIG. 8 is an example of its drive circuit, FIG. 9 is a waveform diagram for explaining its operation, FIG. 10 is an example of another circuit configuration, and FIG. 11 is its driving circuit. A waveform diagram for explaining operation, FIG. 12 is an example diagram of the drive circuit according to this embodiment, FIGS. 13 and 14 are diagrams of other circuit examples, and FIG. 15 is an example diagram of the recording head according to this embodiment, and FIGS. 16 and 17. , 18 is an example of its cross section, the first
Fig. 9 is an example of a block cassette, Fig. 20 is a partially enlarged view, Fig. 21 is an overall configuration diagram, Fig. 22 is a partially enlarged view of the orifice side, and Fig. 23 is an example of another cassette. , FIG. 24 is a diagram showing the overall configuration. 1H1~56T32, 56Q32, 56F3
2} Transistor, H1, H2...heating element, IK
……ink.

Claims (1)

[Claims] 1. A liquid chamber equipped with a discharge port has a large number of thermal energy generating means corresponding to a large number of discharge ports, and the large number of thermal energy generating means generates heat in response to a drive signal. A recording method using a recording means that forms air bubbles in a liquid using thermal energy and discharges the liquid from the ejection port based on the pressure of the bubbles, thereby forming flying droplets and recording. , selecting a large number of thermal energy generating means of the recording means in a time-division manner for each block consisting of a plurality of thermal energy generating means, and supplying the drive signal to the plurality of thermal energy generating means of the selected block. A recording method characterized in that the thermal energy generating means generates thermal energy for ejecting liquid. 2. Claims characterized in that the drive signal is supplied at the same timing to a plurality of thermal energy generating means in the selected block to cause the thermal energy generating means to generate thermal energy. The recording method described in paragraph 1. 3. The drive signal is supplied to a plurality of thermal energy generating means in the selected block at time-divided timing, thereby causing the thermal energy generating means to generate thermal energy. Recording method described in Scope 1. 4. The recording method according to claim 1, wherein the bubbles are formed in a film shape. 5. Recording according to claim 1, wherein the drive signal is generated based on the recording data to be recorded by the recording means, and is supplied to the corresponding thermal energy generating means. Method. 6. The recording method according to claim 1, wherein the drive signal has a pulse shape.