JPH01184148A - Liquid jet recording method - Google Patents

Abstract

PURPOSE:To prevent not only the dripping of a recording liquid from the surface of an emitting orifice but also the generation of a satellite droplet, in a bubble jet type liquid jet recording method, by specifying the ratio of the volume of one liquid droplet and the max. volume of an air bubble. CONSTITUTION:Heat energy is allowed to act on the recording liquid in a liquid chamber to generate air bubbles in a heat energy acted part. The recording liquid is flown from an emitting orifice as a liquid droplet by the acting force accompanied by the volumetric increase of air bubbles. The volume of one liquid droplet at the time of recording is set so as to become equal to or less than the half of that when the air bubbles become the max. volume. As the heat generating resistor 61 of an air bubble generating means, hafnium boride or zirconium boride is pref. In such a state that the heat generating resistor 61 generates no heat, voltage is applied to an electrothermal converter in a pulse like manner according to an image signal while the recording liquid is supplied to a recording head under pressure not emitting the recording liquid from the emitting orifice to obtain a sharp image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid jet recording method, and more particularly to a recording method using a bubble jet type liquid jet recording device.

Conventional non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among them, high-speed recording is possible,
However, the so-called inkjet recording method, which allows recording on plain paper without the need for special fixing treatment, is an extremely powerful recording method, and various methods have been proposed, improved, and commercialized. Some have been developed, and efforts are still being made to put them into practical use.

In this type of inkjet recording method, recording is performed by causing droplets of a recording liquid called ink to fly and adhere to a recording member. There are several types of methods depending on the control method used to control the flight direction of the generated recording liquid droplets.

First, the first method is the one disclosed in USP 3060429 (Tele type method), in which droplets of recording liquid are generated electrostatically, and the generated recording liquid droplets are used as a recording signal. Recording is performed by controlling the electric field in accordance with the temperature and selectively depositing recording liquid droplets on the recording member.

To explain this in more detail, an electric field is applied between the nozzle and the accelerating electrode to eject a negatively charged recording liquid droplet from the nozzle, and the ejected recording liquid droplet is converted into a recording signal. Accordingly, the droplet is caused to fly between x and y deflection electrodes configured to be electrically controllable, and the droplet is selectively deposited on the recording member by changing the intensity of the electric field to perform recording.

The second method is described, for example, in USP 3596275, U
The method disclosed in SP 3298030 etc. (Swe
et method), in which droplets of recording liquid with a controlled amount of charge are generated by a continuous vibration generation method, and a --like electric field is applied to the generated droplets with a controlled amount of charge. Recording is performed on a recording member by flying between deflection electrodes.

Specifically, the orifice (discharge port) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached.
A charged electrode configured to have a recording signal applied thereto is arranged at a predetermined distance in front of the piezo vibrating element, and an electric signal of a constant frequency is applied to the piezo vibrating element to mechanically vibrate the piezo vibrating element, A small droplet of recording liquid is ejected from the ejection port. At this time, charges are electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with an amount of charge corresponding to the recording signal. When a droplet of recording liquid with a controlled amount of charge flies between deflection electrodes to which a constant electric field is uniformly applied, it is deflected according to the amount of charge applied.
Only the droplets carrying the recording signal are allowed to deposit on the recording member.

The third method is, for example, the method disclosed in U.S.P. 3416153 (Hertz method), in which an electric field is applied between a nozzle and a ring-shaped charged electrode, and small droplets of recording liquid are generated by a continuous vibration generation method. This method records by atomizing it. That is, in this method, the atomization state of droplets is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the gradation of the recorded image is produced.

The fourth method is, for example, the method disclosed in USP 3747120 (Stemme method), and this method is fundamentally different in principle from the above three methods.

That is, in all three methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively attached to the recording member. In contrast, this Stemme method
Recording is performed by ejecting and flying small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, the Stemme method applies an electrical recording signal to a piezo vibrating element attached to a recording head that has an ejection port for discharging recording liquid, and converts this electrical recording signal into mechanical vibration of the piezo vibrating element. In this method, recording is performed by ejecting small droplets of recording liquid from the ejection opening according to the mechanical vibrations and adhering them to the recording member.

These four conventional methods each have their own advantages, but there are also points that can be solved in the other method.

That is, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the control of the deflection of the droplets is also electric field control.

Therefore, although the first method is simple in structure, it requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it has a complicated structure, and the electrical control of recording liquid droplets is sophisticated and difficult, and satellite dots are placed on the recording member. There are problems such as easy occurrence of.

The third method has the advantage of being able to record images with excellent gradation by atomizing small droplets of the recording liquid, but on the other hand, it is difficult to control the atomization state and the recorded image may be foggy. There are various problems such as the occurrence of the problem, the difficulty in making the recording head multi-nozzle, and the fact that it is unsuitable for high-speed recording.

The fourth method has relatively many advantages compared to the first to third methods. In other words, the structure is simple, and since recording is performed by ejecting recording liquid from the ejection opening of the nozzle on-demand, it is possible to reduce the number of small droplets that fly as in the first to third methods. Second, it is not necessary to collect droplets that are not needed to record an image, and unlike the first and second methods, there is no need to use a conductive recording liquid, and the material of the recording liquid is It has great advantages such as a high degree of freedom. On the other hand, on the other hand, it is difficult to make a recording head with multiple nozzles due to problems in processing the recording head, and it is extremely difficult to miniaturize a piezoelectric vibrating element having a desired resonance number. This method has disadvantages such as that it is not suitable for high-speed recording because the recording liquid droplets are ejected into flight using the mechanical energy of the mechanical vibration of the piezoelectric vibrating element.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (the above-mentioned USP
No. 3,747,120) describes, as a modification, the use of thermal energy instead of the mechanical vibration energy provided by means such as the piezo vibration element.

That is, the above-mentioned publication describes the use of a heating coil that directly heats a liquid as a pressure increasing means in place of the piezo vibrating element in order to generate steam that causes a pressure increase.

However, in the above publication, the liquid ink in the bag-shaped ink chamber (liquid chamber), which has only one opening through which liquid ink can go in and out, is directly heated and vaporized by energizing the heating coil as a pressure increasing means. However, when discharging liquid continuously and repeatedly, it is not clear how to heat it.
There is nothing to suggest. In addition, the heating coil is located at the deepest part of the bag-shaped liquid chamber far from the liquid ink supply path, which makes the head structure complicated and requires continuous high-speed printing. For repeated use,
It is not suitable.

Moreover, with the technical content described in the above-mentioned publication, it is not possible to quickly prepare for the next liquid discharge after discharging the liquid using the generated heat, which is important in practice.

As described above, conventional methods have advantages and disadvantages in terms of structure, high-speed recording, multi-nozzle recording heads, generation of satellite dots, and fogging of recorded images. There was a restriction that it could only be applied.

Further, Japanese Patent Application Laid-Open No. 55-161665 discloses that in a bubble jet liquid jet recording head, the ejection performance is improved by setting the ink to be 5ac-1 or more.

FIG. 27 is a diagram for explaining an example of the bubble jet liquid jet recording head disclosed in the above-mentioned Japanese Unexamined Patent Publication No. 55-161665, and FIG. 27(a) is a front view of the recording head as seen from the orifice side. Partial view, FIG. 27(b) is the second
FIG. 7 is a partial cross-sectional view taken along a portion indicated by a dashed line XX in FIG. 7(a).

The recording head 11 shown in the figure has a predetermined number of grooves of a predetermined width and depth at a predetermined linear density on the surface of a substrate 13 on which an electrothermal converter 12 is provided. The orifice 15 can be connected by covering it with the attached plate 14.
It has a structure in which a liquid discharge part 16 is formed.

The liquid discharge section 16 has an orifice 15 at its end for discharging droplets, and thermal energy generated by the electrothermal converter 12 acts on the liquid to generate bubbles, which expand and contract in volume. It has a heat acting part 17 which is a place that causes a rapid state change.

The heat acting part 17 is located above the heat generating part 18 of the electrothermal converter 12, and has a heat acting surface 1 in contact with the liquid of the heat generating part 18.
9 is its base.

The heat generating section 18 is a lower layer 20. provided on the substrate 13.
A heating resistance layer 21 provided on the lower layer 20 is provided with electrodes 23 and 24 on its surface for supplying electricity to the core layer 21 in order to generate heat. The electrode 23 is an electrode common to the heat generating section of each liquid discharging section, and the electrode 24 is a selection electrode for selectively generating heat in the heat generating section of each liquid discharging section. It is located along the road.

The upper layer 22 isolates the heating resistance layer 21 from the liquid in the liquid discharge part 16 in order to chemically and physically protect the heating resistance layer 21 from the liquid used, and also connects the electrodes 23 and 24 through the liquid. The heating resistor layer 21 has a protective function of preventing short circuits.

The upper layer 22 has the above-mentioned functions, but
If the heat generating resistor layer 21 is liquid resistant and there is no fear that the electrodes 23 and 24 will be electrically shorted through the liquid, it is not necessary to provide the heat generating resistor layer 21 and the liquid may be directly applied to the surface of the heat generating resistor layer 21. It may also be designed as an electrothermal transducer with a structure in which the two contact with each other.

The lower layer 20 mainly has a heat flow control function.

That is, when discharging droplets, the proportion of heat generated in the heat generating resistor layer 21 being conducted to the heat acting section 17 side is as high as possible, rather than being conducted to the substrate 13 side. rear,
After the power supply to the clogged heat generating resistor layer 21 is turned off, the heat in the heat acting section 17 and the heat generating section 18 is quickly transferred to the substrate 1.
3 side to rapidly cool the liquid and generated air bubbles in the heat acting part 17.

In this way, when discharging droplets, the proportion of the heat flow towards the heat acting section 17 side is as large as possible, and when the electricity to the heat generating resistor layer 21 is turned off, the heat flow towards the substrate 13 side is as large as possible. In order to increase the ratio of In order to stabilize the droplet ejection direction, equalize the droplet ejection speed, and improve the fidelity and reliability of the response to the recording signal, it is necessary to establish the above relationship in the bubble volume change curve. All you have to do is set it and record it.

FIG. 28 shows the electrothermal transducer 12 provided in the recording head.
2 shows the change in volume of bubbles generated in the heat acting section 17 when an electrical signal with a pulse waveform indicated by symbol P is input. Now, the electrothermal converter 12 has 0 at time tfi and time tf.
When it is turned off and a pulsed electric signal P is input,
Bubbles are generated in the heat acting part 17 at time ti, and the volume Vv of the bubbles starts to increase from time ti and reaches the maximum volume Vvp at time tp. When the electric signal P is turned off at time tf, the volume of the bubble Vv after time tp
begins to decrease.

The speed at which the bubble volume Vv decreases when the electric signal P is turned off depends on the rate of change in the bubble volume Vv over time τ□.

That is, by setting the bubble volume change curve to the average value of the time rate of change during heating, the attenuation curve of the bubble volume VV when the electric signal P is turned off can be effectively obtained without using any special cooling means. It can be made steeper, and this allows
This is designed to improve ejection performance.

In this case, the inkjet inputs energy, in other words, pulse voltage, and as a result (output) the recording liquid is ejected from the ejection orifice. The input conditions are described, but the output side (recording liquid ejection) is not considered.

However, in inkjet, good ejection performance can only be obtained when the conditions on the input and output sides are in place, so even if only the input side is regulated, the conditions on the output side (e.g., ejection orifice diameter, flow path dimensions, etc.) ) changes,
Good ejection performance cannot be obtained.

Purpose The present invention was made in view of the above-mentioned circumstances.
In the bubble jet type liquid jet recording method, the purpose is to provide optimal ejection conditions such that the recording liquid does not drip on the ejection orifice surface or satellite droplets are not generated.

1-11 In order to achieve the above object, the present invention has a thermal energy generating means for applying thermal energy to the recording liquid in the liquid chamber, and by the action of the thermal energy, the temperature in the recording liquid is increased. In the liquid jet recording method in which air bubbles are generated in a thermal energy acting part, and the acting force accompanying the increase in the volume of the air bubbles causes the recording liquid to fly as droplets from an ejection orifice and adhere to the recording surface for recording. The volume of one droplet is equal to or less than half the volume of the bubble at its maximum volume. below,
An explanation will be given based on an example of the present invention.

FIG. 1 is a block diagram of the main parts for explaining one embodiment of the present invention, that is, an enlarged view of the ejection orifice part I and the thermal energy acting part (2). In the figure, 31 is a recording liquid, and 32 is a heating element. ,3
3 is a bubble, 34 is an orifice part, and 35 is a recording droplet.
However, in reality, there is no state as shown, that is, a state where the bubble is the largest and a state immediately after the droplet is ejected from the ejection orifice.

In bubble jet technology, droplet ejection is achieved by balancing the acting force due to the volumetric expansion of bubbles, the viscosity of the recording liquid, the resulting fluid resistance in the flow path, and the surface tension at the recording liquid ejection orifice. It is carried out under certain conditions. When the balance is disrupted, for example, when the viscosity is extremely high or low,
Furthermore, if the surface tension at the ejection orifice is extremely large or small, the recording liquid may not be ejected from the ejection port, or may simply drip, or become smooth due to the force of the bubbles. It flows out and takes various forms. Conversely, it can be said that clean ejection is possible when the recording liquid is appropriately cut and has a certain volume.

On the other hand, regarding bubbles, bubble generation is controlled by the energy applied to the thermal energy application section, such as the applied pulse voltage, pulse width, current value, pulse shape, etc.

By observing the generated air bubbles and the recording liquid ejected as a result, the inventor found that when the following conditions are met, there is no satellite droplet between them, and there is no space between them on the ejection orifice surface. It has been found that sharp, stable, and uniform droplets can be ejected without dripping. In other words, the volume of one droplet is the system (here, the system is a head designed with certain dimensions, a recording liquid with certain physical properties, input energy conditions (pulse voltage, pulse width, current value, pulse When the bubble in the shape, etc.) is equal to or less than half of the maximum volume when it reaches the maximum volume = 15-,
Stable discharge is performed. Therefore, according to the invention:
Clear and uniform droplet ejection without satellite droplets and without sagging on the ejection orifice surface can be obtained.

FIG. 2 is a diagram for explaining the operation of a bubble jet head as an example of an inkjet head to which the present invention is applied, FIG. 3 is a perspective view showing an example of the bubble jet head, and FIG. Figure 5 is a perspective view when the head shown in Figure 3 is disassembled into the lid substrate (Figure 4 (a)) and the heating element substrate (Figure 4 (b)), and Figure 5 is Figure 4 (a). 41 is a perspective view of the lid substrate shown in FIG.
42 is a heating element substrate, 43 is a recording liquid inlet, 44 is an orifice, 45 is a channel, 46 is a region for forming a liquid chamber, 47 is an individual (independent) electrode, 48 is a common electrode, and 49 is a heating element. (heater), 50 is a recording liquid (ink), 51 is a bubble, and 52 is a flying ink droplet, and the present invention is applied to such a bubble jet type liquid jet recording head. First, ink jetting by a bubble jet will be explained with reference to FIG. 2. (a) is a steady state, in which the surface tension of the ink 50 and the external pressure are in equilibrium on the orifice surface.

In (b), the heater 49 is heated until the surface temperature of the heater 49 rises rapidly and boiling development occurs in the adjacent ink layer, and microbubbles 51 are scattered.

(c) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 49 is instantaneously vaporized to form a boiling film, and the bubbles 51 grow. At this time, the pressure inside the nozzle increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, causing an ink column to begin to grow from the orifice.

(d) shows a state in which the bubbles have grown to their maximum, and ink 50 corresponding to the volume of the bubbles is pushed out from the orifice surface. At this time, no current is flowing through the heater 49, and the surface temperature of the heater 49 is decreasing. The maximum value of the volume of the bubble 51 is slightly delayed from the timing of applying the electric pulse.

(e) shows a state in which the bubbles 51 are cooled by ink or the like and begin to contract. At the tip of the ink column, it moves forward while maintaining the extruded speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to the decrease in nozzle internal pressure as the bubbles contract, creating a constriction in the ink column. .

In (f), the air bubbles 51 are further contracted, and the ink comes into contact with the heater surface, causing the heater surface to be cooled even more rapidly. At the orifice surface, the external pressure is higher than the nozzle internal pressure, so the meniscus is largely moving into the nozzle. The tip of the ink column becomes a droplet and drops 5 to 1 droplets toward the recording paper.
It is flying at a speed of 0m/sec.

In (g), the air bubbles have completely disappeared in the process of refilling the orifice with ink by capillary action and returning to the state of (a).

FIG. 6 is a detailed diagram for explaining the structure of a bubble generating means using a heating resistor. In FIG. 6, 61 is a heating resistor, 62
63 is an electrode, 63 is a protective layer, and 64 is a power supply device. Useful materials for forming the heating resistor 61 include, for example, tantalum-3in2 mixture, tantalum nitride, nichrome, silver-palladium alloy, and silicon. Examples include borides of semiconductors or metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium.

Among the materials constituting these heating resistors 61, metal borides are particularly excellent, and among them, hafnium boride has the most excellent properties.
This is followed by zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor 61 can be formed using the above-mentioned materials using techniques such as electron beam evaporation and sputtering. The film thickness of the heating resistor 61 is determined according to its area, material, shape and size of the heat-acting part, and actual power consumption, etc. so that the amount of heat generated per unit time is as desired. However, in the normal case, 0.001
~5 μm, preferably 0.01 to 1 μm.

As the material constituting the electrode 62, many commonly used electrode materials can be effectively used, and specifically,
For example, Afi, Ag, An, Pt.

Examples include Cu, and these materials are used to provide a predetermined size, shape, and thickness at a predetermined location by a method such as vapor deposition.

The characteristics required of the protective layer 63 are to protect the heat generating resistor 61 from the recording liquid without preventing the heat generated by the heat generating resistor 61 from being effectively transferred to the recording liquid. Examples of useful materials for forming the protective layer 63 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide. It can be formed by The thickness of the protective layer 63 is normally 0.01 to 10 μm, preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm.

The recording head created as described above is supplied with recording liquid at a pressure such that the recording liquid will not be ejected from the ejection port when the heating resistor does not generate heat. When a voltage was applied and recording was performed, a clear image was obtained.

FIG. 7 is a block diagram showing an example of the heating element drive circuit at that time, and 71 is a known optical angler's cuff sensor unit for reading consisting of a photodiode or the like, and the image signal input to the optical angler's cuff sensor unit 71 is is processed by a processing circuit 72 consisting of a circuit such as a comparator, and then input to a drive circuit 73. The drive circuit 73 drives the recording head 74 by controlling the pulse width, pulse amplitude, repetition frequency, etc. according to the input signal.

For example, in the simplest recording, the input image signal is discriminated between black and white in the processing circuit 72 and input to the drive circuit 73. In the drive circuit 73, the pulse width and pulse amplitude for obtaining an appropriate droplet diameter and the repetition frequency for obtaining a desired recording droplet density are converted into controlled signals to drive the recording head 74.

In addition, as another recording method that takes gradation into consideration, one is to perform recording by changing the droplet diameter, and the other is to perform recording by changing the number of recording droplets as follows. You can also do it.

First, in the recording method of changing the droplet diameter, an image signal inputted to the optical angler cuff sensor unit 71 is outputted as a drive signal with a pulse width and a pulse amplitude of each level determined to obtain the desired droplet diameter. Drive circuit 7 having multiple circuits for
The processing circuit 72 determines which of the three signal levels should be used for outputting the signal and processes the signal. In addition, in the method of changing the number of recorded droplets, the optical angler's cuff sensor section 7
The input signal to 1 is A/D converted and outputted in the processing circuit 72, and according to the output signal, the drive circuit 73 controls the recording head so that recording is performed by changing the number of ejected droplets per one input signal. Outputs a signal to drive 74.

Alternatively, a similar device may be used to supply the recording liquid to the recording head 74 at a pressure higher than the pressure at which the recording liquid overflows from the ejection port without the heating resistor generating heat, while performing electrothermal conversion. When recording was performed by applying a voltage to the body in the form of continuous repeated pulses, it was confirmed that droplets of a number corresponding to the applied frequency were ejected stably and with a uniform diameter.

From this point of view, it has been found that the recording head 74 is extremely effectively applied to continuous ejection at high frequencies.

Further, since the recording head, which is the main part of the recording apparatus, is minute, a plurality of recording heads can be easily arranged, and a high-density multi-orifice recording head is possible.

FIG. 8 is a diagram for explaining another means for generating bubbles in the recording liquid, in which 81 is a laser oscillator, 82 is a light modulation drive circuit, 83 is a light modulator, 84 is a scanner, and 85 is a condensing lens, and a laser beam generated by a laser oscillator 81 is pulse-modulated in an optical modulator 82 according to an image information signal that is inputted to an optical modulator driving circuit 82, electrically processed, and outputted. . The pulse-modulated laser beam passes through a scanner 84 and is focused by a condensing lens 85 on the outer wall of the thermal energy acting section, heating the outer wall 86 of the recording head and recording inside -23= Bubbles are generated within the liquid 87. Alternatively, the wall 86 of the thermal energy application section is made of a material that is transparent to the laser beam, and the laser beam is focused by the condensing lens 85 on the recording liquid 87 inside to directly heat the recording liquid. Bubbles may be generated by

FIG. 9 is a diagram for explaining an example of a printer using a laser beam as described above. This example shows an example in which the entire area (width) is covered.

Laser light emitted from the laser oscillator 81 is guided to the entrance opening of the optical modulator 83. In the optical modulator 83, the laser beam undergoes intensity modulation according to the image information input signal to the optical modulator 83. The modulated laser beam is reflected by a reflecting mirror 8.
8 bends its optical path toward the beam expander 89 and enters the beam expander 89 . The beam expander 89 expands the beam diameter by 124= while keeping the beam parallel. Next, the laser beam with expanded beam diameter is
The light is incident on a rotating polygon mirror 90 that rotates at a constant high speed. The laser beam swept by the rotating polygon mirror 90 is imaged by a condensing lens 85 on the outer wall 86 of the thermal energy acting part of the drop generator or on the recording liquid inside. As a result, air bubbles are generated in each thermal energy applying portion, and recording droplets are ejected to perform recording on the recording paper 92.

FIG. 10 is a diagram showing yet another bubble generating means. In this example, a pair of discharge electrodes 100 arranged on the inner wall side of the thermal energy application section receive a high voltage pulse from a discharge device 101, This device generates an electrical discharge in water, and the heat generated by the electrical discharge instantly forms bubbles.

11 to 18 are diagrams showing specific examples of the discharge electrode shown in FIG. 10, respectively. In the example shown in FIG. 11, the electrode 100 is made into a needle shape to concentrate the electric field and efficiently (
It is designed to cause a discharge (with low energy).

In the example shown in FIG. 12, two flat plate electrodes are used so that air bubbles are stably generated between the electrodes. The position of generated bubbles is more stable than needle-shaped electrodes.

The example shown in FIG. 13 is one in which the electrode has a substantially coaxial hole. The holes in the two electrodes serve as guides, making the position of the bubbles even more stable.

The example shown in FIG. 14 is a ring-shaped electrode, which is basically the same as the example shown in FIG. 13, and is a modified example thereof.

In the example shown in FIG. 15, one side is a ring-shaped electrode and the other side is a needle-shaped electrode. The ring-shaped electrode aims to stabilize the generated bubbles, and the needle-shaped electrode aims to improve efficiency by concentrating the electric field.

In the example shown in FIG. 16, one ring-shaped electrode is formed on the wall surface of the thermal energy application section. In addition to the effects of the example shown in FIG. 15, this is aimed at ease of manufacturing by forming electrodes in a two-dimensional manner on the substrate. A plurality of such planar electrodes can be easily manufactured with high density by vapor deposition (or sputtering) or photoetching techniques. Particularly effective for multi-arrays.

In the example shown in FIG. 17, the ring-shaped electrode forming portion of the example shown in FIG. 16 is shaped along the outer periphery of the electrode and is raised one step higher than the surroundings. Again, the aim is to stabilize the generated bubbles, and the stability is greater than that shown in FIG. 15 by adding a three-dimensional guide.

The example shown in FIG. 18, contrary to the example shown in FIG. 17, has a structure in which the ring-shaped electrode forming part is sunk downward from the periphery.
The generated bubbles are stably formed.

FIGS. 19 to 26 are diagrams for explaining the control mechanism when the recording head is incorporated into a recording apparatus to actually perform recording. First, referring to FIGS. 19 to 22, Each electric/thermal converter 1101, 11 according to an external signal
02. . . . 1107 are controlled simultaneously to each discharge port 1111, 1112 . . . . An example will be described in which liquid is discharged simultaneously from 1117 in accordance with an external signal. First, FIG. 19 is an overall block diagram, in which an input signal from a computer keyboard is input from an interface circuit 121 to a data generator 122.Next, a desired character in a character generator 123 is selected and printed. The data generator 122 arranges the data signals in the form. The data arranged in the data generator 122 is once stored in the buffer circuit 124, and is sequentially sent to the driver circuits 125□-125□ for each converter 1.
10□.

1102, . . . 1107 are driven to eject droplets. The control circuit 126 is a circuit that controls the input/output timing of each circuit and outputs a signal instructing the operation of each circuit.

20 is a timing chart explaining the operation of the buffer circuit 124 shown in FIG.
A character clock 5101 generated by a character generator generates a data signal 5102 arranged in
At the other timing, output signals are sequentially provided to the drive circuits 1251 to 1257. In the example of FIG. 19, input/output is performed using one buffer circuit, but control using a plurality of buffer circuits, so-called double buffering, may also be performed. That is, when one buffer circuit is inputting, the other buffer circuit outputs, and at the next timing, each buffer circuit performs the opposite operation. When double buffering is used, droplets can be ejected continuously.

In this way, seven converters 1101, 110 . .

...1107 are simultaneously controlled according to the droplet ejection timing chart shown in FIG. 21, for example, and as a result, droplets are printed from seven ejection ports as shown by the O mark in FIG. 22. This can be done by discharging. Note that each of the signals 5111 to A117 is transmitted through seven converters 3-10.
This is a signal applied to each of 1,110□, . . . 110□.

23 to 26 are diagrams for explaining an example of a control mechanism that sequentially controls each electric/thermal converter according to an external signal to sequentially eject droplets from each ejection port. A block diagram of the entire device is shown. In FIG. 23, external signals 5130 pass through interface circuit 131 and are arranged by data generator 132 in an order convenient for printing. In the example shown in FIG. 23, in which data is printed column by column, data is read out from the character generator 133 for each column and temporarily stored in the column buffer circuit 134. Then, at the timing when column data is read from the character generator 133 and input to the column buffer circuit 134□, another data is output from the column buffer circuit 1341, and the drive circuit 135 is operated.

FIG. 24 shows a timing chart explaining the operation of the buffer circuit 134. The column data signal output from the drive circuit 135 is controlled by the gate circuit 137 for each converter 1101, 110□, . . .
1107 are sequentially driven. A timing chart at that time is shown in FIG. In the figure, 5141 is a character clock, 5142 is a column buffer circuit 134□
5143 is the input signal to the column buffer circuit 134□
5144 is the input signal to the column buffer circuit 1341
The signal 5145 is output from column buffer circuit 1.
The signal output from 34□ is shown. As a result, for example, according to the droplet ejection timing as shown in FIG.
Droplets are sequentially ejected from the seven ejection ports, and as shown in FIG.
The characters shown by the marks are printed. In addition, signal 5151
Each of 5157 to 5157 is one of the seven transformers 110. .

110, . . . , signals applied to each of 1107 are shown.

Although the control mechanism has been explained using an example of character printing, the same method is used when obtaining a copy image or the like.

Further, in this example, an example using a print head having seven ejection ports has been described, but it is also possible to perform printing in a similar manner when a full-line multi-orifice type print head is used.

The recording liquid used in the recording device according to the present invention is selected from the materials and the ratios of the composition components are adjusted so as to have the thermophysical properties and other physical properties described below, as well as those used in conventional recording methods. In addition to being chemically and physically stable like the recording liquid, it also has excellent responsiveness, fidelity, and thread-forming ability, does not harden in the liquid path, especially at the discharge port, and can flow in the flow path according to the recording speed. The physical properties are adjusted to give properties such as being able to circulate at a high speed, being quickly fixed on the recording member after recording, having sufficient recording density, and having a good shelf life.

The recording liquid used in the recording device according to the present invention is composed of a liquid medium, a recording agent for forming a recorded image, and an additive added to obtain desired characteristics. Depending on the type and composition ratio of additives, it is possible to obtain either aqueous, non-aqueous, soluble, electrically conductive, or insulating properties.

Liquid media are broadly classified into aqueous media and non-aqueous media, but the liquid media used are those that are combined with other selected constituents so that the recorded recording liquid has the above-mentioned physical properties. The combination is selected from the following.

Such non-aqueous media include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ee-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol. , C1-C10 alkyl alcohols such as octyl alcohol, nonyl alcohol, and decyl alcohol; For example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene, and quidylol; For example, carbon tetrachloride, trichloroethylene, and tetrachloride; Halogenated hydrocarbon solvents such as chloroethane and dichlorobenzene; Ether solvents such as ethyl ether, butyl ether, ethylene glycol diethyl ether, and ethylene glycol monoethyl ether; For example, acetone, methyl ethyl ketone, methyl propyl ketone, methyl amyl ketone, Ketone solvents such as cyclohexanone; ester solvents such as ethyl formate, methyl acetate, propyl acetate, phenyl acetate, and ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol;
Examples include petroleum-based hydrocarbon solvents.

These enumerated liquid media are appropriately selected and used so as to satisfy the compatibility with the recording agent and additives used and the various properties described below as a recording liquid. Two or more types may be mixed and used as appropriate within the range in which a recording liquid having the characteristics can be prepared. Moreover, these non-aqueous media and water may be mixed and used within the above conditions.

Among the above-mentioned liquid media, water or water/alcohol-based liquid media are preferred in consideration of pollution, ease of availability, ease of preparation, and the like.

In addition to ensuring that the recording liquid to be prepared has the above-mentioned physical properties, the recording agent is also used to prevent sedimentation and agglomeration in liquid channels and recording liquid supply tanks due to long-term storage, as well as transport pipes and liquid channels. It is necessary to select and use materials in relation to the liquid medium and additives so as not to cause clogging. From this point of view, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or poorly soluble in the liquid medium, the particles of the recording agent when dispersed in the liquid medium are It can be used if the diameter is made sufficiently small.

The recording material that can be used is appropriately selected depending on the recording member so as to fully suit the recording conditions. Recording agents include dyes and pigments.

The dye that can be effectively used is one that satisfies the properties described below for the prepared recording liquid, and examples of dyes that are preferably used are, for example, direct printing dyes as water-soluble dyes, basic dyes, In addition to acid dyes, soluble vat dyes, acid mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcohol-soluble dyes, oil-soluble dyes, disperse dyes, thren dyes, naphthol dyes, It is selected from reactive dyes, chromium dyes, 1:2 type complex salt dyes, 1:1 type complex salt dyes, azoic dyes, cationic dyes and the like.

Specifically, for example, Resolin Lil Blue PRL, Resolin Yellow PCG, Resolin Pink PRR, Resolin Green PB (manufactured by Bayer), and Sumikaron Blue 5.
-BG, Sumikaron Red E-EBL, Sumikalon Yellow E-40L, Sumikalon Brilliant Blue 5-B
L (manufactured by Sumitomo Chemical), Diamond Mirror Yellow -HG-
8E, Diamond Thread BN-'SE (manufactured by Mitsubishi Kasei), Kayalon Polyester Light Flavin 4GL,
Kayalon Polyester Blue 3R-8F, Kayalon Polyester Yellow YL-8E, Kaya Set Turquis Blue 776, Kaya Set Yellow 902, Kaya Set Red 026, Prosion Onlerado H-2B, Prodion Blue H-3R (Japanese leaf underside) ), Revafix Golden Yellow P-R, Revafix Pril Red P
-B, Revafix Pril Orange P-OR (manufactured by Buyer), Sumi, Fix Yellow GR8, Sumi Fix B, Sumi Fix Pril Red BS, Sumi Fix Pril Blue PB, Direct Black 40 (
manufactured by Jumin Chemical), Diamirror Brown 3G, Diamirror Yellow G, Diamirror Blue 3R, Diamirror Prill Blue B, Diamirror Prill Red BB (
(manufactured by Mitsubishi Kasei), Remazol Red B, Remazol Blue 3R, Remazol Yellow GNL, Remazol Prill Green 6B (manufactured by Hoechst), Cibacron Pril Yellow, Cibaclon Pril Red 4GE (manufactured by Ciba Geigy), Indico, Direct Tape Black E-Ex, Diamine Black BH, Congo Red, Serious Black BH, Orange■, Amid Black 10'B, Orange R○, Metaneil Yellow, Victoria Scarlet, Nigrosine, Diamond Black PBB (or more) Manufactured by Egame), Diacit Blue 3G
, Diacit Fast Green GW, Diacit Milling Navy Blue R, Indanthrene (manufactured by Mitsubishi Kasei), Zapon dye (manufactured by BASF), Orazole dye (manufactured by CIBA), Lanasin dye (manufactured by Mitsubishi Kasei), Diacryl Orange RL-E, Diacrylic Brilliant Blue 28-E, Diacrylic Turkis Blue BG-
E (manufactured by Mitsubishi Kasei) and the like, those which give the above-mentioned physical properties to the recording liquid prepared can be preferably used.

These dyes are appropriately selected as desired and used after being dissolved or dispersed in the liquid medium used.

As pigments that can be effectively used, many of inorganic pigments and organic pigments are suitably used. Specific examples of such pigments include inorganic pigments such as cadmium sulfide, sulfur, selenium, zinc sulfide, cadmium sulfoselenide, yellow lead, zinc chromate, molybdenum red, Guinée green, titanium white, zinc white, and zinc white. Handle, chromium oxide green, red lead, cobalt oxide, barium titanate, titanium yellow, iron black, navy blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine blue, calcium carbonate, magnesium carbonate, lead white, Examples include cobalt violet, cobalt blue, emerald green, and carbon black.

Most of the organic pigments are classified as dyes and often overlap with dyes, but specifically, the following are preferably used.

(a) Insoluble azo type (naphthol type) Brilliant Carmine BS, Lake Carmine FB, Brilliant Fast Scarlet, Lake Red 4R, Rose Red, Permanent Red R, Fast Red FO
R, Lake Bordeaux 5B, Vermilion N091, Vermilion NO.2, Toluidine Maroon.

(b) Insoluble azo type (anilide type) Diazo Yellow, Fast Yellow G, Fast Yellow 10G, Diazo Orange, Vulcano = 39-range, Balazolone Red.

(c) Soluble azo Lake Orange, Brilliant Carmine 3B, Brilliant Carmine 6B, Brilliant Scarlet G, Lake Red C, Lake Red D, Lake Red R, Watching Red, Lake Bordeaux 10B, Bon Maroon, Bon Maroon M0 (d ) Phthalocyanine-based Phthalocyanine Blue, Fast Sky Blue, Phthalocyanine Green.

(e) Dyeing Lake Yellow Lake, Eosin Lake, Rose Lake, Violet Lake, Blue Lake, Green Lake, Sepia Lake.

(f) Mordant system Alizarin Lake, Madakamine.

(g) Vat-dyed type Indanlene series, Fast Blue Lake (GGS).

(h) Basic dye lake system Rhodamine Lake, Malachite Green Lake.

(i) Acid dye lake type Fast Sky Blue, Quinoline Yellow Lake, Quinacridone type, Dioxazine type.

The quantitative relationship between the liquid medium and the recording agent is determined based on conditions such as clogging of the liquid path, drying of the recording liquid in the liquid path, bleeding when applied to the recording member, and drying speed in addition to the formulation. The recording agent is usually 1 to 50 parts by weight, preferably 3 parts by weight, based on 100 parts of the liquid medium.
~30 parts, optimally 5 to 10 parts.

When the recording liquid is a dispersion system (a system in which the recording agent is dispersed in a liquid medium), the particle size of the dispersed recording agent depends on the type of recording agent, recording conditions, inner diameter of the liquid path, ejection opening diameter, and recording member. It is determined as desired depending on the type of recording agent, but if the particle size is too large, sedimentation of the recording agent particles may occur during storage, resulting in uneven density or clogging of the liquid path. This is undesirable because it may cause density unevenness in the recorded image.

Taking this into consideration, the particle size of the recording agent used as a dispersion recording liquid is usually 0.01 to 30μ, preferably 0.01 to 20μ, and optimally 0.01 to 8μ. It is desirable to Furthermore, the particle size distribution of the dispersed recording agent is preferably as narrow as possible, and is usually D±3μ,
A preferable value is D±1.5μ (where D represents the average particle size).

Examples of the additives used include viscosity modifiers, surface tension modifiers, PH modifiers, resistivity modifiers, wetting agents, infrared absorbing exothermic agents, and the like.

In addition to obtaining the above-mentioned physical property values, the viscosity modifier and surface tension modifier must also be able to flow through the liquid path at a sufficient flow rate depending on the recording speed, and prevent the recording liquid from going around at the discharge port of the liquid path. It is added for the purpose of preventing bleeding (spreading of the spot diameter) when applied to a recording member.

The viscosity modifier and surface tension modifier are selected from commonly known agents as long as they are effective and do not adversely affect the liquid medium and recording material used, so as to satisfy the desired properties. used.

Specifically, viscosity modifiers include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, water-soluble acrylic resin, polyvinyl pyrrolidone,
Gum arabic starch and the like can be exemplified as suitable examples.

Surface tension modifiers that are suitably selected and used as desired include anionic, cationic, and nonionic surfactants, and specifically, as anionic surfactants, polyethylene glycol ether sulfate, polyethylene glycol ether sulfate, Ester salts, etc., cationic types such as poly2-vinylpyridine derivatives, poly4-vinylpyridine derivatives, etc., nonionic types such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan monoalkyl Examples include ester, polyoxyethylene alkylamine, and the like.

In addition to these surfactants, there are also amino acids such as jetanolamine, propatoolamine, and morpholinic acid, basic substances such as ammonium hydroxide and sodium hydroxide, and substituted pyrrolidones such as N-methyl-2-pyrrolidone. Used effectively.

These surface tension modifiers do not adversely affect each other or other constituents, and provide the above-mentioned physical properties to the recording liquid being formulated, so that a recording liquid having a desired value of surface tension is formulated. If necessary, two or more types may be mixed and used within the range specified above.

The amount of these surface tension modifiers to be added is determined as appropriate depending on the type, other constituent components of the recording liquid to be prepared, and desired recording characteristics. Usually 0.0001 to 0.1 parts by weight, preferably 0.0001 to 0.1 parts by weight.
The amount is desirably 0.001 to 0.01 parts by weight.

The pH adjuster is used to maintain a predetermined pH value in order to maintain the chemical stability of the prepared recording liquid, for example, to prevent changes in physical properties due to long-term storage and to prevent sedimentation and aggregation of the recording agent and other components. It is added at the right time and in an appropriate amount within a range that does not deviate from the physical property values.

- The pH adjuster preferably used in the present invention includes:
Almost any pH can be used as long as it can control the pH value to a desired level without adversely affecting the recording liquid being prepared.

Specific examples of such pH adjusters include lower alkanolamines, monovalent hydroxides such as alkali metal hydroxides, and ammonium hydroxide.

These pH adjusters are added in a necessary amount so that the recording liquid to be prepared has a desired pH value within a range that does not deviate from the above-mentioned physical property values.

The lubricant to be used is one that is more effective than those commonly known in the technical field related to the present invention, especially one that is thermally stable, as long as the recording liquid to be prepared does not deviate from the various physical properties listed below. are preferably used. Specific examples of such lubricants include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as butylene gelcol and hexylene glycol; Lower alkyl ethers of diethylene glycol such as ethylene glycol methyl ether, diethylene glycol methyl ether, and diethylene glycol ethyl ether; Glycerin; Lower alcohol oxytriglycols such as methoxytriglycol and ethoxytriglycol; N-vinyl-2-
Examples include pyrrolidone oligomer; and the like.

These lubricants are added in the required amount as desired so that the recording liquid satisfies the desired characteristics.
The amount added is usually 0.1 to 1% based on the total weight of the recording liquid.
0 νt%, preferably 0.1 to 8 νt%, optimally 0.2
It is desirable that the content be ~7wt%.

In addition to being used alone, the above lubricants may be used in combination of two or more types provided that they do not adversely affect each other.

In the recording liquid used in the present invention, the above-mentioned additives are added in necessary amounts as desired, and in addition, additives that have excellent formation properties and film strength of a recording liquid film when attached to a recording member are used. For example, resin polymers such as alkyd resins, acrylic resins, acrylamide resins, polyvinyl alcohol, and polyvinylpyrrolidone may be added.

The recording liquid used in the present invention has specific heat, coefficient of thermal expansion, thermal conductivity, viscosity,
In the case of recording using charged recording droplets, it is desirable to prepare the composition so that characteristic values such as surface tension, pH, and specific resistance fall within the range of characteristic conditions.

That is, these characteristics have important relationships with the stability of the stringing phenomenon, responsiveness and fidelity to thermal energy effects, image density, chemical stability, fluidity within the liquid path, etc. Therefore, in the present invention, it is necessary to pay sufficient attention to these matters when preparing the recording liquid.

It is desirable that the above-mentioned properties of the recording liquid that can be effectively used in the present invention be as shown in Table 1 below, and all of the listed physical properties are shown in Table 1. It is not necessary to satisfy such numerical conditions; it is sufficient that some of these physical properties take values that satisfy the conditions in Table 1, depending on the required recording characteristics. specific heat,
The coefficient of thermal expansion, thermal conductivity, viscosity, and surface tension are preferably defined by the values shown in Table 1. Of course, it goes without saying that the more of the above-mentioned properties of the blended recording liquid that satisfy the values shown in Table 1, the better the recording will be. As is clear from the above description, according to the present invention, sharp and uniform droplets can be ejected without satellite droplets and without sagging on the ejection orifice surface.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts for explaining an embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of a bubble jet head as an example of an inkjet head to which the present invention is applied. , FIG. 3 is a perspective view showing an example of a bubble jet head, FIG. 4 is an exploded perspective view, FIG. A diagram for explaining the structure of the bubble generating means, FIG. 7 is a block diagram for explaining an example of a heating element drive circuit, and FIG. 8 is a diagram for explaining an example of the bubble generating means using laser light. , FIG. 9 is a diagram for explaining an example of a printer, FIG. 10 is a diagram for explaining an example of a bubble generating means using electric discharge, and FIGS. 11 to 18 are diagrams for explaining an example of a printer. FIG. 10 shows a specific example of the discharge electrode, FIGS. 19 to 22, and 23 to 26 each illustrate a control example when the recording head is incorporated into a recording device to perform recording. 27 to 28 are diagrams for explaining the prior art. 31... Recording liquid, 32... Heating element, 33... Bubbles, 34... Orifice portion, 35... Recording droplets. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 2NN

Claims (1)

[Claims] 1. It has a thermal energy generating means for applying thermal energy to the recording liquid in the liquid chamber, and by the action of the thermal energy, bubbles are generated in the thermal energy acting part in the recording liquid, and the volume of the bubbles is increased. In a liquid jet recording method in which recording is performed by ejecting the recording liquid as a droplet from an ejection orifice using the acting force associated with the droplet and adhering it to the recording surface, the volume of one droplet is equal to the maximum volume of the bubble. A liquid jet recording method that is characterized by being equal to or less than half of what it used to be.