JPH03173654A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To realize highly precise gradation recording by varying the energy and the number of input pulses to a heating element, required for formation of a single picture element, according to picture information in a recorder where recording liquid is jetted by a force produced through thermal volumetric expansion of a bubble. CONSTITUTION:Driving signal comprises a group of N pulses for a single picture element, and driving voltage Vp is varied. The length of an ink column is varied in step by varying the number N of pulse so that the ink column is elongated as the number N increases. The ink column also elongates as the driving voltage Vp increases. lt means that the time difference between arrivals of the leading edge and the trailing edge of the ink column to a paper will vary, hence it means that the adhesion area of ink will vary because a nozzle moves relatively to the paper at a predetermined speed. Since the nozzle has a predetermined diameter, variation of the length of the ink column causes variation of delivery of ink. Consequently, a dot diameter corresponding to picture information can be obtained and the dot diameter can be varied by varying the number of pulse required for formation of a single picture element and by varying the driving voltage in a region where the dripping speed varies according to the driving voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a liquid jet recording apparatus, and more particularly to an inkjet printer.

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 (Tele type method) disclosed in, for example, US Pat. Recording is performed by controlling the droplets with an electric field in accordance with a recording signal to selectively attach recording liquid droplets onto a recording member.

To explain this in more detail, an electric field is applied between the nozzle and the accelerated electrode to eject a small droplet of the recording liquid charged in the - manner from the nozzle, and the ejected small droplet of the recording liquid is recorded. Recording is performed by flying the droplet between x and y deflection electrodes that are configured to be electrically controllable in accordance with a signal, and selectively depositing the droplet on the recording member by changing the intensity of the electric field.

The second method is a method (Sweet method) disclosed in, for example, U.S. Pat. No. 3,596,275, U.S. Pat. Recording is performed on a recording member by generating small droplets with a controlled amount of charge and flying the generated droplets between deflection electrodes to which a negative electric field is applied. .

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 charging electrode configured to have a recording signal applied thereto is placed a predetermined distance apart from the piezoelectric vibrating element, and an electrical signal of a constant frequency is applied to the piezoelectric vibrating element to mechanically vibrate the piezoelectric vibrating element. Then, small droplets of recording liquid are 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 added, and the droplet carries the recording signal. only can be deposited on the recording member.

The third method is, for example, the method disclosed in U.S. Pat. No. 3,416,153 (Hertz method),
In this method, an electric field is applied between a nozzle and a ring-shaped charged electrode, and small droplets of recording liquid are generated and atomized using a continuous vibration generation method to perform recording. 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 US Pat. No. 3,747,120 (Stemme method), and this method is fundamentally different in principle from the above three methods.

4. In other words, in all three methods, the droplets of the recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively placed on the recording member. In contrast to recording by attaching
Recording is performed by ejecting 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 deflection control 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 the recording liquid droplets is sophisticated and difficult. -There are problems such as easy formation of dots.

The third method has the advantage of being able to record images with excellent gradation by atomizing recording liquid droplets, but on the other hand, it is difficult to control the atomization state and fog occurs in the recorded image. In addition, it is difficult to create a multi-nozzle recording head.
There are various problems such as being 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. During.

5 6 There is no need to collect droplets that are not needed for recording an image, and there is no need to use a conductive recording liquid as in the first and second methods, and the material of the recording liquid is It has great advantages such as two large degrees 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 (corresponding to the above-mentioned US Pat. No. 3,747,120) discloses, as a modification,
It is described that thermal energy is used instead of using mechanical vibration energy by means such as the piezo vibration element described above.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording device that uses a heating coil that directly heats the liquid as a pressure increasing means instead of a piezo vibrating element to generate steam that causes a pressure increase. has been done.

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, there is no suggestion as to how to heat the liquid when continuously and repeatedly discharging the liquid. 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. It is not suitable for repeated use.

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 head, generation of satellite dots, and fogging of recorded images, etc., and it is possible to take advantage of these advantages. There was a restriction that it could only be applied to certain purposes.

The thermal inkjet recording method is a so-called drop
Very effectively applied to on-demand recording methods,
Not only can discharge orifices be provided at a high density, but also driving parts (i.e., heat generating parts) can be provided at the same density as the discharge orifices, making it possible to easily achieve high-density multi-orifice recording. It is the law. However, there are still problems that need to be solved in order to achieve higher-definition image quality such as with copiers. Among these, an extremely effective method for obtaining high-resolution, high-quality images is to impart gradation to recording pixels. However, conventionally, in bubble diene 1 to recording methods, a method for expressing gradation has been to use multiple electrical/thermal converters provided in one flow path, as described in Japanese Patent Publication No. 62-48585. It is known to perform gradation recording by variably controlling the input timing shift of drive signals manually applied to each part of the body. Furthermore, Japanese Patent Publication No. 62-46358 discloses that the recording medium liquid supplied into one liquid chamber is heated by a plurality of heating elements provided at positions that heat the recording medium liquid according to the level of a signal representing information to be recorded. A technique has been disclosed in which the diameter of ejected droplets is changed by selecting and driving a predetermined number of heating elements. However, as is clear from their specifications, both techniques relate to a so-called edge shooter type head in which a heating element is provided along a flow path leading to a discharge port. On the other hand, in those that form and use one heating element,
Although it is possible to increase the density and make full use of its characteristics, in the case of a device in which multiple heating elements are formed along the flow path leading to one discharge port as described above, , the number of control electrodes for independently controlling each heating element increases, making it difficult to increase the density, and the original characteristics cannot be utilized. In addition, in the case of the edge shooter type, the distance from the discharge port to the heating element is the discharge characteristic (
In the example above, where the distances of each heating element from the ejection port differ by 90 degrees, it is necessary to control them to achieve gradation. requires extremely difficult technology and is not necessarily practical.

Further, in JP-A-59-124863 and JP-A-59-124864, in addition to generating bubbles for ejection, another bubble for adjusting ejection energy is generated to perform gradation recording. Alternatively, a technique has been disclosed in which a small opening is provided in the ejection energy adjustment section and the size of the droplet is changed to perform gradation recording. However, since the heating element for discharging and the heating element for adjusting the discharge energy are separated, there are problems in that it is difficult to match the timing of the pressure from both, and the location of the heating element for adjusting the discharge energy. There is a problem in that the area is in a dead end, making it difficult to supply new ink, and the ink temperature in that area increases, making it difficult to drive the heating element for ejection energy adjustment under certain stable conditions. Satisfactory gradation recording cannot necessarily be obtained.

Further, Japanese Patent Publication No. 59-31943 discloses a technique for performing gradation recording by causing a heat generating portion having a heat generation amount adjustment structure to generate an amount of heat according to gradation information. However, in a heating element having a trapezoidal planar structure as shown in the specification, wire breakage tends to occur in the narrow portion due to thermal stress and/or the impact force when bubbles disappear, making it unreliable. Lacks sex. Further, a structure in which the protective film, heat storage layer, and heating element have a thickness gradient in the cross-sectional structure requires difficult techniques using current thin film forming techniques, and even if possible, it would be extremely expensive.

Furthermore, Japanese Patent Application Laid-Open No. 6:3-42869 discloses a technique for changing the number of times bubbles are generated by changing the energization time of the heating element, thereby making the discharge amount variable. Since the time is changed, the energy required to form one pixel is extremely large, and therefore the amount of heat generated is also extremely large.

Furthermore, Japanese Patent Application Laid-Open No. 59-207265 discloses that a heating element is driven by a group of pulses for one pixel to repeatedly generate and generate bubbles.
This is a technology that expresses gradation by changing the number of pulses (that is, the number of pulses in a group of pulses) by extinguishing them, and was developed in Japanese Patent Application Laid-Open No. 63
The ejection energy may be smaller than that in the -42869 publication. However, as a result of experiments conducted by the present inventors, as shown in Figure 4, the diameter of the dots on the recording paper changes stepwise with respect to the number of instantaneous pulses, and is twice or three times the diameter of the dots produced by one pulse. It was changing... However, the diameter of the drum 1 in recording paper is usually from several tens of micrometers to several hundred micrometers.
When driven by a group of pulses, the dot diameter changes, but the change is extremely rough. For this reason, when performing gradation recording aimed at high-definition recording on copiers, etc., it is required to change the dot diameter even more finely, and the technique disclosed in Japanese Patent Application Laid-Open No. 59-207265 uses a single pulse to print dots. The diameter must be extremely small, and therefore the heating element, flow path, nozzle diameter, etc. must be made ultra-fine, making processing difficult and reducing yields, resulting in an expensive head. A problem arises in which the

Purpose The present invention was made in view of the following drawbacks of the prior art, and its main purpose is to perform high-definition gradation recording.

Another object is to provide a gradation recording head capable of varying the dot diameter in high steps.

Still another object is to provide a gradation recording head with an extremely simple structure without using special auxiliary means or difficult processing techniques.

Still another object is to provide an inexpensive gradation recording head with good yield.

Structure In order to achieve the above object, the present invention includes an ejection port for ejecting a recording liquid, a thermal energy generator for applying thermal energy to the recording liquid, and generating bubbles by the thermal energy, In the liquid jet recording device 3-14-, in which the recording liquid is caused to fly from the ejection port by the acting force accompanying the increase in the volume of the bubbles, the heating element is heated to form one pixel according to image information. This method is characterized in that gradation recording is performed by changing the number of input pulses and input energy.

First, based on FIG. 2, the principle of ink ejection using the bubble jet method that preferably implements the present invention will be explained.

(,,) is a steady state, in which the surface tension of the ink 2 and the external pressure are in equilibrium on the orifice surface.

In (b), the heater 3 is heated until the surface temperature of the heater 3 rises rapidly and a boiling phenomenon occurs in the adjacent ink layer, and microbubbles 4 are scattered.

(Q) shows a state in which the adjacent ink layer that is rapidly heated on the entire surface of the heater 3 instantaneously vaporizes to form a boiling film, and the bubbles 4 grow. At this time, the nozzle internal pressure increases by the amount of bubble growth, and the balance with the external pressure on the orifice surface is lost, and an ink column begins to grow from the orifice.

(d) shows a state in which the bubble has grown to its maximum, and ink 2 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 3, and the surface temperature of the heater 3 is decreasing. The maximum value of the volume of the bubble 5 is slightly delayed from the timing of electric pulse application.

(e) shows a state in which the bubbles 5 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 5 further contract and the ink comes into contact with the heater surface, causing the heater surface to cool down 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 moves toward the recording paper.
It is flying at a speed of 10 m/see.

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). 8 is a flying ink droplet.

FIG. 3 is an overall perspective view of a bubble jet recording head based on the above jetting principle. In the figure, 9 is a heating element substrate, 10 is a lid substrate, 11 is an ink supply port, and 12 is an orifice.

FIG. 1 is a diagram for explaining an embodiment of a liquid jet recording apparatus according to the present invention, and is a diagram for explaining the structure of a bubble generating means using a heating resistor. Figure 1(a) is a partial front view of the recording head seen from the orifice side;
b) is a partial cutaway view taken along the line indicated by dashed line XX in FIG. 1(a). In the figure, 13 is a substrate;
14 is a lid substrate, 15 is an orifice, 16 is a liquid discharge part, 1
7 is a heat action part, 18 is a heat generation part, 19 is a heat action surface, 20
21 is an electrothermal converter (heating resistor), 22 is a protective layer, and 23 and 24 are electrodes.

A predetermined number of grooves having a predetermined density and a predetermined width and depth are provided on the surface of the substrate 13 on which the electrothermal converter is provided, and the orifice 1 is bonded so as to be covered with the lid substrate 14.
625 having a structure in which a liquid discharge portion 16 and a liquid discharge portion 16 are formed.
is a channel wall, and 26 is an upper layer. The liquid discharge part 16 has an orifice at its terminal end for discharging droplets, and thermal energy generated by the electrothermal converter 21 acts on the liquid to generate bubbles, causing a rapid state due to expansion and contraction of the volume. It has a heat acting part 17 where changes are caused.

The heat acting part 17 is located above the heat generating part 18 of the electrothermal converter 21, and has a heat acting surface 19 in contact with the liquid of the heat generating part 18.
is its base. The heat generating section 18 includes a lower layer 20 provided on the substrate 13, a heat generating resistor layer 21 provided on the lower layer 20, and a heat generating resistor layer 21 that is energized to generate heat. Electrodes 23, 24 are provided on its surface. The electrode 23 is an electrode common to the heat generating section of each liquid discharging section, and the electrode 24 is a selective electrode for selectively generating heat in the heat generating section of each liquid discharging section, and is a selective electrode for selectively generating heat in the heat generating section of each liquid discharging section. It is located along the road.

7- The material of the substrate 13 is glass, ceramics, metal, silicon, or the like.

Useful materials for the heating resistor 21 include:
For example, a mixture of tantalum-8i○2, tantalum nitride,
Examples include nichrome, silver-palladium alloys, silicon semiconductors, and borides of metals such as hafnium, lanthanum, zirconium, titanium, tungsten, molybdenum, niobium, chromium, and vanadium.

Among the materials constituting these heating resistors 21, metal borides are particularly excellent, and among them, hafnium boride has the best properties.
This is followed by zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor 21 is made of the above material by photolithography, electron beam evaporation, sputtering, CVD,
It can be formed using a technique such as plasma CVD. The film thickness of the heating resistor 21 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 normal cases, it is 0.001~
The thickness is 5 μm, preferably 0.01 to 1 μm.

As the material constituting the electrodes 23 and 24, many commonly used electrode materials can be effectively used, and specifically, for example, Al, Ag, and Au.

Examples include metals such as Pt and Cu, and alloys thereof,
Using these materials, it is provided at a predetermined position with a predetermined size, shape, and thickness by a method such as vapor deposition or sputtering.

The characteristics required of the protective layer 22 are such that the heat generated by the heat generating resistor 21 is not prevented from being effectively transferred to the recording liquid, and the heat generated by the heat generating resistor 21 is protected from the impact force when the recording liquid or bubbles disappear.
It is to protect.

Examples of useful materials for forming the protective layer 22 include silicon oxide, magnesium oxide, aluminum oxide, tantalum oxide, and zirconium oxide. These include electron beam evaporation, sputtering, CVD method,
It can be formed using a thin film forming method such as a plasma CVD method or a vapor phase growth method. The thickness of the protective layer 22 is usually 0.
．． It is desirable that the thickness be 0.01 to 10 μm, preferably 0.1 to 5 μm, most preferably 0.1 to 3 μm.

Further, after the protective layer is formed, an electrode protective layer may be provided on the electrode portion except for the heat generating portion 17. The characteristics required of the electrode protective layer include excellent ink resistance, excellent heat resistance, and good electrical insulation. Therefore, it is required to have good film forming properties, have few pinholes, and not swell or dissolve in the ink used. Many materials that satisfy the above conditions can be used as the material for forming the electrode protective layer. For example, silicone resin, fluororesin, aromatic polyamide, addition polymerization type polyimide,
We manufacture resins such as metal chelate polymers, titanate esters, epoxy resins, phthalate resins, thermosetting phenol resins, P-vinyl phenol resins, Zylock resins, and triazine resins, as well as high-density multi-orifice type recording heads. If any, apart from the organic materials mentioned above,
It is desirable to use an organic material that is extremely easy to process using fine photolithography.

A flow path is formed using a photosensitive resin on the heating element substrate configured as described above. A cavitation-resistant resin such as photosensitive polyamide varnish or photosensitive polyimide varnish is applied using a coating means such as a spinner or a roll coater. The layer thickness of the photosensitive resin is not particularly limited, but considering its practicality as an inkjet recording head, it should be at least about 5 to 100 μm.
Preferably 10 to 50 ILm, optimally 15 to 50 ILm
It is desirable to do so. Therefore, it is preferable that the photosensitive resin be one that can be laminated to such a thickness.

Commercially available photosensitive resins include the above-mentioned photosensitive polyamide varnishes, namely Printite EF95 and Dobron (Topl).
on), nylon print,
Or photosensitive polyimide, i.e. Photonice VR-31
40, Selectilux HTR-2 is preferred.

In this way, the substrate on which the photosensitive resin is laminated is subjected to 1 22 treatments such as exposure or development as described below to form an ink channel wall made of the photosensitive resin. In the following, the photosensitive resin will mainly be Photoneese VR-31.
These processes will be described using the case of 4.0 as an example, but the method of forming the ink flow path wall may be any method depending on the photosensitive resin used.

Prebaking is performed as necessary on the substrate laminated with photosensitive resin. After the prebaking is completed, a photomask having a desired pattern is placed on the Photonease VR-3140, and then exposure is performed through the photomask. After the exposure, the unexposed portion of the second VR-3140 film is developed using a developer DV-505 for Photonice VR-3140, and the unexposed portion is dissolved and removed to form a flow path. form a groove. After dissolving and removing the unexposed portions in this way, post-baking is performed to harden the Fo 1-2 remaining on the substrate, and the Fo 1-2 which is the wall of the ink flow path having the desired pattern is formed on the substrate. -su VR-3
140 cured film is formed.

Although the method for forming a liquid type photosensitive resin such as Photonease VR-3140 has been described above, it can also be formed using a photosensitive dry film. The thus formed substrate and the lid substrate 1 for forming the ceiling portion of the flow channel.
0 is bonded via an adhesive layer. The material for the lid substrate is
The same material as the heating element board can be used. That is, silicon, glass, ceramics, etc. A photosensitive dry film is provided in a semi-cured state on a substrate made of these materials,
After bonding to the substrate with grooves formed therein, heat is applied for final curing, and the heating element substrate and the lid substrate are bonded.

The recording liquid used in the present invention is different from the recording liquid used in conventional recording methods, in addition to the selection of materials and the ratio of composition components so that it has the thermophysical properties and other physical properties described below. In addition to being chemically and physically stable, it also has excellent responsiveness, fidelity, and thread-forming ability, does not solidify in the liquid path, especially at the discharge port, and flows through the flow path at a speed that corresponds to the recording speed. The physical properties are adjusted so as to provide properties such as being able to do a good job, quickly fixing to the recording member after recording, having sufficient recording density, and having a good shelf life.

The recording liquid used in the present invention is composed of a liquid medium, a recording agent that forms a recorded image, and additives added to obtain desired characteristics. By selecting the type and composition ratio, it is possible to obtain any of aqueous, non-aqueous, soluble, conductive, and #@marginal 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, aceton, methyl amyl ketone, and methyl amyl ketone Ketone solvents such as , methyl amyl ketone, and 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 25- = 26- 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 suitable dyes include direct dyes as water-soluble dyes, basic dyes, and acidic dyes. In addition to dyes, soluble vat dyes, acidic mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcoholic dyes, oil-soluble dyes, disperse dyes, thren dyes, naphthol dyes, and reactive dyes. The dye is selected from 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 EEBL, Sumikalon Yellow E-40L, Sumikalon Brilliant Blue 5-BL
(manufactured by Sumitomo Chemical), Diamond X Yellow-HG-
8E, Diamond Thread BN-8E (manufactured by Mitsubishi Kasei), Kayalon Polyester Light Flavin 4GL, Kayalon Polyester Blue 3R-8F, Kayalon Polyester Yellow YL-8E, Kaya Set Turkey Blue 776, Kaya Set Yellow 902, Kayaset Red 026, Prodion Red H-2B, Prodion Blue H-3R (Japanese bodywork), Revafix Golden Yellow P-R, Revafix Pril Red P-B
, Revafix Pril Orange P-GR (manufactured by Buyer), Sumifix Yellow GR8, Sumifix B, Sumifix Pril Red BS, Sumifix Pril Blue PB, Direct Black 40 (manufactured by Sumitomo Chemical), Dia Mirror Brown 3G, Diamirror Yellow 〇, Diamirror Blue 3R, Diamirror Prill Blue B, Diamirror Prill Red BB (manufactured by Mitsubishi Kasei), Remazol Red B, Remazol Blue 3
R, Remazol Yellow GNL, Remazol Prill Green 6B (manufactured by Hoechst), Cibaclon Prill Yellow, Cibaclon Prill Red 4GE (manufactured by Ciba Geigy), Indico, Direct Tape Black E-E
x, Diamine Black BH, Congo Red, Serious Black BH, Orange■, Amido Black IOB
, Orange RO, Metaneal Yellow, Pictoria Scarlet, Nigrosine, Diamond Black PBB (
Diacit Blue 3G, Diacit Fast Green GW, Diacito Milling Navy Blue R, Indanthrene (made by Mitsubishi Kasei),
Zapon dye (manufactured by BASF), orazole dye (CI
B A), Lanasin Dye (manufactured by Mitsubishi Kasei), Diacrylic Orange RL-E, Diacrylic Brilliant Blue 2B-E, Diacrylic Turkis Blue BG-E (manufactured by Mitsubishi Kasei), etc. It is preferable to use those which are applied to the recording liquid in which the liquid is prepared.

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, Guinea green, titanium white, zinc white,
Bengara, chromium oxide green, red lead, acid Kobal 1~, barium titanate, titanium yellow, iron black, navy blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine blue, calcium carbonate, magnesium carbonate, Examples include lead white, 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 1-Carmine BS, Lake Carmine FB, Brilliant Fast Scarlet, Lake Red 4R,
Rose red, permanent red R, fast red F
OR, Lake Bordeaux 5B, Vermilion NO.1, Vermilion N002, Toluidine Maroon.

(b) Insoluble azo type (anilide type) Diazo Yellow, Fast Yellow G, Fast Yellow 10G, Diazo Orange, Palkan Orange, Balazolone Red.

(c) Soluble Azo Lake Orange, Brilliant 1-Carmine 3B, Brilliant Carmine 6B, Brilliant Scarlet G, Lake Red C, Lake Red D, Lake Red R, Watching Red, Lake Bordeaux 10B, Bon Maroon L, Bon Maroon M .

(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 Industhrene 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 not only by the formulation but also by conditions such as clogging of the liquid path, drying of the recording liquid in the liquid path, bleeding when applied to the recording area, and drying speed. , 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, the recording conditions, the inner diameter of the liquid path, and the diameter of the ejection port.

It is determined as desired depending on the type of recording member, etc., but if the particle size is too large, the recording agent particles may settle during storage, resulting in uneven concentration or clogging of the liquid path. This is undesirable because it may cause unevenness or 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 may be 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. selected and used.

Specifically, suitable examples of the viscosity modifier include polyvinyl alcohol ruboxymethylcellulose, hydroxyethylcellulose, methylcellulose, water-soluble acrylic resin, polyvinylpyrrolidone, and gum arabic starch.

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.

As the PH adjuster suitably used in the present invention,
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 gellicol and hexylene glycol; for example, ethylene Lower alkyl ethers of diethylene glycol such as 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.
0wt%, preferably 0.1-8wt%, 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.

The recording liquid used in the present invention is added with the above-mentioned 37-38- additives in the required amount as desired, but the formation properties and film strength of the recording liquid film when attached to the recording member are further improved. In order to obtain excellent properties, 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,
When recording using recording droplets with surface tension, p I-1, and 4i1''rtx, it is desirable that the composition be prepared so that characteristic values such as 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. As for specific heat, coefficient of thermal expansion, thermal conductivity, viscosity, and surface tension, it is desirable that the values shown in Table 1 be specified. Of course, it goes without saying that the more of the above-mentioned properties of the prepared recording liquid that satisfy the values shown in Table 1, the better the recording will be. (Left below) In a bubble jet recording head with a structure as shown in Table 1, conventionally, a heating element is rapidly heated in a short period of time to instantly vaporize the ink layer on the surface of the heating element to create a boiling film. By causing so-called film boiling, which is caused by expansion, stable bubbles are generated and discharged. Therefore, conventionally, the voltage applied to the heating element is 1.02 of the voltage Vo (threshold voltage) at which bubbles begin to generate.
It was being driven at ~1.3 times. However, the inventors found that 1
00 ILrn x 100 Pm size, resistance value 7
A heating element with a 2 μm thick protective layer on a 0Ω heating element, I
As a result of making a prototype of A plate and observing the bubble generation when heated with electricity in pure water, the applied voltage vp was 14V (41. in Figure 5), 15V (42 in the figure), and 16V ( At 43) in the same figure, a derailment occurred, and at that time,
As shown in Figure 5, there is no significant difference in the volume increase rate (dv/dt) and maximum volume (Vmax) of bubbles even when the voltage is changed. This is because a vapor film is formed on the surface, and the vapor film becomes a heat insulating layer that prevents heat transfer from the heat generating part to the liquid layer, and after the vapor film is formed, it expands due to inertia regardless of the temperature of the heat generating part surface.

Therefore, stable bubbles can always be created in the film boiling state, but even if the voltage is slightly changed, there is no significant difference in the amount of ejected droplets. In addition, the applied pulse rlJ at this time is 6 μs, llJ
It was driven at a dynamic frequency of 5 KHz.

On the other hand, the present inventors used Ai? A flow path and discharge orifice were provided using the method described above, and a prototype of 8 orifices/mm was fabricated. In this head, when the ejection speed 1~ was measured when a pulse application signal was applied by changing the applied voltage VP, the results shown in FIG. 6 were obtained. Here, the droplet velocity is
It is the average velocity between the orifice and 0.5 mm beyond the orifice. Moreover, the ejection shape between them is a very long columnar shape (100 μm or more). 61 is the tip speed of the flying liquid column, and 62 is the rear end speed. From this point on, the trailing end speed was constant at about 5 m/s, and the tip speed varied from 6 m/s to 15 m/s. When the state of the bubbles at this time was observed in a vehicle having approximately the same physical properties as the ink, it was found that bubbles in a stable film boiling state were generated at voltages higher than V P A complete film boiling was not formed between s and a so-called transition boiling. At this time as well, the bubbles were synchronized with the human input signal, and their size corresponded to the voltage. In addition, Vp□ is the droplet ejection starting voltage Vp
The voltage was 24V, which is 1.5 times that of 2 (16V). The transition boiling referred to here is a state that does not lead to complete derailment In, "Introduction to Heat Transfer" (written by Yoshibu Koto, Yokendo edition, p. 295-p.
336), it is a boiling phenomenon in the region where nucleate boiling transitions to film boiling, and like film boiling, a vapor film is formed and then separates as bubbles, causing the ink Ifη
In this state, the vapor layer contacts the heating element surface again and continuously forms a vapor film.

Using this head, one pixel was driven by a pulse group of N pulses using a motion signal as shown in FIG.

At this time, the pulse width (t, ) is 6 μs, the period (t2) of the pulse in the pulse group is 30 μs, that is, the frequency (fl) of the pulse in the pulse group is 33.3 KHz, and the period (t3) of the pulse group is 30 μs. ) is 2 m s, that is, the frequency of the pulse group is driven at 500 I-I z, and the driving voltage vp is 1.6
It was varied from V to 24V. As the recording medium, MN Matsu 1 coated paper manufactured by Mitsubishi Paper Mills was used.

In addition, the distance d between the nozzle and the paper affects the position of the driver 1, so it is desirable to set it to an appropriate value.
．． 1≦d≦20mm, preferably 0.5≦d≦10mm
, optimally, 0.5≦d≦5 mm. Here, evaluation was made with d=1 mm. The results are shown in Table 2. (Left below) Table 2 5-6- Also, if Table 2 is expressed as a graph, it will look like Figure 8, which shows that by changing the number of pulses and the IIK dynamic voltage Vp, smooth changes in dot diameter can be obtained. was completed.

In addition, when observing this ejection state while synchronizing it with a strobe, it was found that by changing the number of pulses, the length of the ink column changed in stages, and as the N increased, the ink column became longer. . Furthermore, it was found that the length of the ink column changed by changing vp, and the longer Vp was increased, the longer the ink column became. This means that the time difference between when the leading edge reaches the paper and when the trailing edge arrives changes, and since the nozzle normally moves relative to the paper at a fixed speed, The area to which the ink adheres will change. Also, if the length of the ink column changes, considering that the nozzle diameter is constant, the ejection amount itself will change, and the number of pulses and droplet speed to form one pixel will depend on the driving voltage. In other words, by changing an arbitrary drive voltage of 1.5 V pz or less from the ejection start voltage (V P 2 ), the dot diameter can be adjusted according to the image information. I was able to get Furthermore, this dragon 1
~If the diameter is changed only by changing the number of pulses, only the amount of change corresponding to the number of pulses can be obtained. That is, the number of pulses is 1.
When the dot diameter is varied up to 15 pulses, the number of changes in the dot diameter is 15 steps.However, according to the present invention, it was possible to obtain an extremely multistep change in the dot diameter. For example, if the number of pulses is varied between 1 and 15 pulses and the voltage value is varied in 4 steps, 60 steps of dot diameter can be obtained. In addition, the voltage value is the ejection starting voltage (V p 2 )
and 1.5V P 2, and it is also possible to change the dot diameter in multiple stages.

Also, as shown in Fig. 8, at each pulse number,
It is characterized in that the amount of change in the dot diameter with respect to a voltage near the ejection start voltage (V P 2 ) (between the ejection start voltage (V P 2 ) and Vp2+2V) is larger than the amount of change with respect to a voltage higher than that. For this reason, near the discharge start voltage, that is, on the low voltage side, the amount of voltage change should be set finely (for example, at 0.2 V intervals), and on the high voltage side, by setting it coarsely, the change in the diameter of the driver 1 can be made more linear. It is possible to obtain extremely high quality gradation recording.

In the embodiments of the present invention, an example of a so-called edge shooter type head has been described, but the embodiments of the present invention can also be effectively used in a side shooter type head. Compared to the shooter type, the side shooter type can supply ink from around the heat generating part, and therefore can supply ink quickly according to the number of pulses in the pulse group, so the period of the pulses in the pulse group ( t2) can be shortened,
In addition, if the heating elements are close to each other, such as in an edge shooter type, as the number of pulses increases, heat buildup on the heating element board will increase, resulting in greater variation in discharge, splash-like discharge, or failure to discharge. This may result in a limit to the number of pulses, or the period (t,) of the pulse group may be lengthened, or a substrate with extremely high thermal conductivity may be used to improve heat dissipation. However, since the side shooter type has more flexibility in the position of the heating element, it is more advantageous than the edge shooter type in dealing with these problems.

Further, in the embodiment of the present invention, the number of pulses in the pulse group and the driving voltage are changed, but the same effect can be obtained by changing the number of pulses in the pulse group and the pulse duration (tl). I was able to get it.

FIG. 9 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 light 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 causing the inner recording liquid 87 to be heated. to generate air bubbles. Alternatively, the wall 86 of the thermal energy acting section is made of a material that is transparent to the laser beam, and the recording liquid 8 inside is
Bubbles may be generated by condensing the light so as to focus on the recording liquid and directly heating the recording liquid.

FIG. 1-0 is a diagram for explaining an example of a printer using a laser beam as described above.
1 (for example, A4 size 111) is accumulated so as to cover the entire area.

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 in the direction of the beam expander 89 and enters the beam expander 89.

The beam expander 89 expands the beam diameter while remaining parallel light. Next, the laser light whose beam diameter has been expanded 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, bubbles are generated in each thermal energy application area,
Recording droplets are ejected and recorded on recording paper 92.

FIG. 11 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. A discharge is caused in the recording liquid, and the heat generated by the discharge instantly forms bubbles.

12 to 19 are diagrams showing specific examples of the discharge electrode shown in FIG. 11, respectively. In the example shown in FIG. 12, 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. 13, 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. 14 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. 15 has a ring-shaped electrode, and is basically the same as the example shown in FIG. 14, and is a modified example thereof.

The example shown in FIG.

One is a ring-shaped electrode and the other is a needle-shaped electrode. Ring-shaped electrode improves the stability of generated bubbles)
(2) The aim is to increase efficiency by concentrating the electric field using needle-shaped electrodes.

In the example shown in FIG. 17, 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. 16, 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 fabricated with high density using vapor deposition (or sputtering) or photo-etching techniques. Particularly effective for multi-arrays.

In the example shown in FIG. 18, the ring-shaped electrode forming portion of the example shown in FIG. 17 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. 16 by adding a three-dimensional guide.

The example shown in FIG. 19, contrary to the example shown in FIG. 18, has a structure in which the ring-shaped electrode forming part is sunk downward from the periphery.
The generated bubbles are stably formed.

As is clear from the explanation in ``Effects'' 2, according to the present invention, 1.
Since a pixel is formed by multiple pulses and the input energy (voltage and/or pulse [11]) to the heating element is changed, unlike conventional methods, only a very coarse stepwise change in diameter can be achieved. This eliminates the problem of not being able to obtain a high-gradation image, and since the diameter can be changed to Drawer 1 in extremely high steps and can be easily controlled, it has the excellent effect of being able to obtain high-gradation image quality. . Moreover, this made it possible to extremely easily realize high-definition gradation recording without using any special auxiliary means. Moreover, for this reason, it was possible to manufacture the gradation recording spatula 1 at a high yield and at low cost.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram for explaining an embodiment of a liquid jet recording apparatus according to the present invention, and is a diagram for explaining the configuration of a bubble generating means using a heating resistor. ) is a front partial view of the recording spatula 1~ as seen from the orifice side, (b) is the X in (a)
- A cutaway partial view taken along the X-ray line; FIG. 2 is a diagram for explaining the principle of ink ejection using the bubble jet method; FIG. 3 is an overall perspective view of the bubble jet recording head; Fig. 4 shows the relationship between the dot diameter on the recording paper and the number of driving pulses, Fig. 5 shows how bubbles are generated when the voltage applied to the heating element is varied, and Fig. 6 shows the relationship between the dot diameter on the recording paper and the number of driving pulses.
The figure shows the relationship between the ejection speed and the drive voltage, Figure 7 shows the drive signal, and Figure 8 shows the change in the diameter of the driver 1 as the number of pulses and the drive voltage change. figure,
Fig. 9 is a diagram for explaining an example of a bubble generating means using laser light, Fig. 10 is a diagram for explaining an example of a printer using laser light, and Fig. 11 is a diagram for explaining an example of a printer using electric discharge. FIGS. 12 to 19, which are diagrams for explaining an example of the bubble generating means, are diagrams showing specific examples of the discharge electrode shown in FIG. 11, respectively. 15... Orifice, 16... Liquid discharge part, 17...
・Heat acting part, ], 8... Heat generating part, 19... Heat acting surface,
2o: Lower layer, 21: Heat generating resistor, 22: Protective layer, 23.24: Electrode, 25: Channel wall.

Claims (1)

[Claims] 1. A discharge port for discharging the recording liquid, a thermal energy generator for applying thermal energy to the recording liquid, generating bubbles by the thermal energy, and using an acting force as the volume of the bubbles increases, In a liquid jet recording device that causes the recording liquid to fly from the ejection port, gradation recording is performed by changing the number of input pulses and input energy to the heating element to form one pixel according to image information. A liquid jet recording device featuring: