JPS6211035B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a recording liquid for inkjet recording that uses thermal energy to fly the recording liquid as droplets to record. [Prior Art] Non-impact recording methods have recently attracted attention because the noise generated during recording is so small that it can be ignored. Among these, the so-called inkjet recording method, which enables high-speed recording and can record on so-called plain paper without the need for special fixing processing, is an extremely powerful recording method. Some have been devised, improved and commercialized, and others are still being worked on to put them into practical use. In this inkjet recording method, recording is performed by causing droplets of a recording liquid called ink to fly and adhere to a recording member. The methods are classified into several types depending on the control method for controlling the flight direction of the generated recording liquid droplets. Typical examples are USP3060429 (Teletype method), USP3596275 (SWeet method), USP3298030 (Lewis/Brown method), USP3416153 (Hertz method), USP3747120 (Stemme method), USP3683212 (Zoltan method), USP3946398 (Kyser/Brown method), Sears method) is listed in each publication. The recording methods described in these publications include applying mechanical vibration to a pressurized liquid stream to separate droplets;
Alternatively, the recording liquid is ejected from the ejection port by a change in volume due to mechanical action of a recording liquid chamber filled with the recording liquid to form flying droplets. In contrast to these methods, Japanese Patent Publication No. 54-13783, USP 2556550, JP 51-132036, and JP 51-19303 describe an inkjet recording method that uses thermal energy. has been done. [Problems to be solved by the invention] However, the method described in Japanese Patent Publication No. 54-13783 is essentially USP3298030, USP3596275.
This method differs from the method described in , in that it uses changes in surface tension due to thermal energy of the ink (recording liquid) to separate droplets from a pressurized jet. The method described in USP2556550 is a method for recording by discharging ink from an ejection port by thermal expansion of the ink or the substrate. This method applies thermal energy locally to the ink in the open ink reservoir to form bubbles, and records the droplets that are generated when the bubbles float through the ink and burst when they reach the ink surface. This is a method of recording by attaching it to paper. Neither method uses thermal energy to eject ink from an ejection port to form flying droplets, and the recording liquid (ink) used
Regarding the physical properties that can be applied to inkjet recording methods that utilize thermal energy, there are only descriptions of water-based inks or water and amino black inks, and there is no further information. Nothing is written. Further, USP 3,747,120 enumerates a heating coil as an example of pressure increasing means, but only mentions ink as the recording liquid used. As described above, in the past, inkjet recording methods that utilize thermal energy, particularly recording liquid supplied to a liquid path, are ejected from an ejection port communicating with the liquid path using thermal energy to form flying liquid. No recording liquid has been provided that is applied to an inkjet recording method in which recording is performed by forming droplets, and that provides a clear recorded image without the generation of satellite dots or fogging of the recorded image. [Object of the Invention] Therefore, the present invention has been made in view of the above points, and does not generate satellite dots.
An object of the present invention is to provide a recording liquid for inkjet recording that utilizes novel thermal energy and can provide clear recorded images without fog. [Means to Solve the Problems] According to the present invention, recording liquid supplied to a liquid path is ejected from an ejection port communicating with the liquid path using thermal energy to form flying droplets for recording. A recording liquid for inkjet recording that utilizes thermal energy to perform a process contains a liquid medium, a recording agent and an additive in an amount of 1 to 50 parts by weight per 100 parts by weight of the liquid medium, and has a specific heat of 0.1. ~4.0J/gk, thermal expansion coefficient 0.1
×10 ^-3 ~1.8×10 ^-3 deg ^-1 , thermal conductivity 0.1×10 ^-3 ~
50×10 ^-3 W/cm・deg, viscosity at 20℃ is 0.3~
A recording liquid for inkjet recording using thermal energy is provided, which is characterized by having a surface tension of 30 CPS and a surface tension of 10 to 60 dyne/cm. [Related Explanation] First, an overview of the inkjet recording method to which the recording liquid of the present invention is applied will be explained with reference to FIG. FIG. 1 is an explanatory diagram for explaining the basic principle of an inkjet recording method to which the recording liquid of the present invention is applied. An orifice (discharge port) can be created in the nozzle liquid path 1 by using an appropriate pressurizing means such as a pump.
A recording liquid 3 is supplied to which a pressure P is applied to such an extent that it is not ejected. Now, when the recording liquid 3a in the liquid path 1 at a distance l from the ejection port 2 is subjected to the action of thermal energy, the width of the liquid path 1 changes depending on the amount of energy applied due to a sudden change in the state of the recording liquid 3a. A part or substantially all of the recording liquid 3b existing in the recording liquid 3b is ejected from the ejection port 2, flies as a droplet in the direction of the recording member 4, and adheres to a predetermined position on the recording member 4. The size of the small droplet 5 of the recording liquid ejected from the ejection port 2 and flying is determined by the amount of thermal energy applied and the width Δl of the portion 3a that is affected by the thermal energy of the recording liquid existing in the liquid path 1. The inner diameter d of the liquid path 1, the distance l from the position of the discharge port 2 to the position where thermal energy is applied, the pressure P applied to the recording liquid, the specific heat, thermal conductivity, and coefficient of thermal expansion of the recording liquid, etc. Dependent. Therefore, by changing any one or more of these factors, the size of the droplet 5 can be easily controlled, and the droplet diameter or spot diameter can be adjusted to any desired diameter as desired. It is possible to record on the recording member 4 using the same method. In particular, being able to arbitrarily change the distance l means that the position at which thermal energy is applied during recording can be changed as desired, and therefore the amount of applied thermal energy per unit time can be changed. At least, the size of the recording liquid droplets 5 ejected and flying from the ejection opening 2 can be arbitrarily controlled during recording, and a recorded image with gradation can be easily obtained. Thermal energy applied to the recording liquid 3 in the liquid path 1 may be applied continuously over time, or may be applied discontinuously by turning ON and OFF in pulses. When acting in a pulsed manner, the frequency, amplitude, and pulse width can be easily selected and changed as desired, so the size of the droplet and the number of droplets generated per unit time can be easily changed. The number of pieces can be controlled extremely easily. When thermal energy is applied to the recording liquid 3 in a temporally discontinuous manner, the applied thermal energy can carry recording information. In this case, according to the recording information signal, the recording liquid 3
Since thermal energy is applied to the recording member 4, all the droplets 5 ejected and flying from the ejection port 2 carry recording information, and therefore all of them adhere to the recording member 4. When thermal energy is not made to carry recording information and is applied discontinuously to the recording liquid 3, it is preferable to act discontinuously at a certain frequency. In this case, the frequency depends on the type of recording liquid used within the scope of the present invention and its physical properties, the form of the liquid path, the volume of the recording liquid in the liquid path, the recording liquid supply speed to the liquid path, and the diameter of the ejection port. , is determined as desired in consideration of recording speed, etc., but usually 1.
~1000KHz, preferably 50-500KHz. When thermal energy is applied continuously over time, the size of the droplet and the number of droplets generated per unit time are the amount of thermal energy applied per unit time and the record in the liquid path 1. The inventors have confirmed that it mainly depends on the pressure P applied to the liquid, the specific heat, thermal expansion coefficient and thermal conductivity of the recording liquid, and the energy for the droplets to fly out from the ejection port 2. There is. Therefore, by controlling the amount of thermal energy and/or pressure P acting per unit time among these, the size of the droplets and the number of droplets No. can be controlled. In the present invention, the thermal energy that acts on the recording liquid 3 is generated by supplying thermal conversion energy to a thermal conversion body. As the heat conversion energy, any energy that can be converted into thermal energy can be used, but electrical energy and electromagnetic wave energy are usually preferably used because of their ease of supply, transmission, control, etc. Electromagnetic energy includes lasers, masers,
Energy such as infrared rays, ultraviolet rays, visible light, high frequency waves, and electron beams can be mentioned. In particular, laser energy is preferred because of its high heat conversion efficiency, ease of transmission, supply and control, and miniaturization of the device. In the case of employing electrical energy as heat conversion energy in the present invention, the heat conversion body may be provided in direct contact with the liquid path 1, or a material with high heat conduction efficiency may be interposed between the heat conversion bodies. In either case, the thermal energy generated from the heat converter provided in the liquid path 1 is transmitted to the recording liquid 3 to act on it. Furthermore, in the case where this electric energy is employed, at least the portion of the liquid path 1 on which the electric energy acts may itself be constituted by a heat converter. When electromagnetic wave energy is employed as the heat converter energy, the heat converter may be the recording liquid 3 itself, or may be attached to the liquid path 1. For example, if the recording liquid 3 contains an electromagnetic wave energy absorbing heat generating substance, the recording liquid 3 will directly absorb the electromagnetic wave energy and generate heat, causing a state change and causing the recording liquid to flow through the discharge port 2 of the liquid path 1. The droplets can be ejected and fly, and if, for example, an electromagnetic energy absorbing heat generating layer is provided on the external surface of the liquid path 1,
The layer absorbs electromagnetic wave energy and generates heat, and the generated thermal energy is transmitted to the recording liquid 3 via the liquid path forming member, thereby causing a state change in the recording liquid 3 and forming a droplet. It may be ejected out of the path 1. As the recording member 4 used in the present invention, all those commonly used in the technical field of the present invention are effective. Examples of such recording materials include paper, plastic sheets, metal sheets, and laminated sheets of these materials, but paper is preferred from the viewpoint of medium recording performance, cost, and handling. It is considered suitable. Examples of such paper include plain paper, high-quality paper, lightweight coated paper, coated paper, art paper, and the like. [Detailed Description of the Invention] The recording liquid of the present invention can be used in conventional recording methods in addition to the selection of materials and the ratio of composition components so as to have the above-mentioned thermophysical property values and other physical property values. In addition to being chemically and physically stable like other recording liquids, it also has excellent responsiveness, fidelity, and threading ability, and does not solidify in the liquid path, especially at the discharge port. be able to be distributed at a speed commensurate with the recording speed, be quickly fixed on the recording material after recording, have sufficient recording density, and have a good shelf life.
Physical property values are adjusted to give properties such as The recording liquid of 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 insulating properties. The liquid medium used in the present invention includes:
The liquid medium used is roughly divided into aqueous media and non-aqueous media, but the liquid medium used is as follows, taking into consideration the combination with other selected components so that the recording liquid to be prepared has the above-mentioned physical properties. selected from those of In the present invention, such non-aqueous media include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and benzyl alcohol. Alkyl alcohols having 1 to 10 carbon atoms such as alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, and decyl alcohol; Hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene, and xylol; Halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, tetrachloroethane, 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, and methyl Ketone solvents such as propyl ketone, 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; Petroleum Examples include hydrocarbon solvents. These liquid media listed above are appropriately selected and used so as to satisfy the compatibility with the recording agent and additives used and the above-mentioned properties 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. Further, within the above conditions, these non-aqueous media and water may be mixed and used. 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, in the present invention, it is preferable to use a recording agent that is soluble in a liquid medium, but even a recording agent that is dispersible or poorly soluble in a liquid medium may be dispersed in the liquid medium. It can be used if the particle size of the recording agent is made sufficiently small. The recording agent that can be used in the present invention is appropriately selected depending on the recording member so as to fully suit the recording conditions thereof. The dyes that can be effectively used in the present invention are those that can satisfy the above-mentioned properties of the prepared recording liquid, and those that are preferably used are, for example, direct dyes as water-soluble dyes, Basic dyes, acid dyes, soluble vat dyes, acidic mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, alcoholic dyes, oil-soluble dyes, disperse dyes, etc., as well as thren dyes. , naphthol dyes, 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 Grill Blue
PRL, Resolin Yellow PGG, Resolin Pink
PRR, Resolin Green PB (manufactured by buyers),
Sumikaron Blue S-BG, Sumikalon Red E
-EBL, Sumikalon Yellow E-4GL, Sumikalon Brilliant Blue S-BL (manufactured by Sumitomo Chemical), Diamondx Yellow BG-SE, Diamondx Thread BN-SE (manufactured by Mitsubishi Chemical), Kayalon Polyester Light Fla Pin 4GL, Kayalon Polyester Blue 3R-SF, Kayalon Polyester Yellow YL-SE, Kaya Set Turquis Blue 776, Kaya Set Yellow 902, Kaya Set Red 026, Procion Red H-2B, Procion Blue H-3R (Japanese version) Pharmaceutical), Leverfix Golden Yellow PR, Leverfix Brill Red P-B, Leverfix Brill Orange P-GR (manufactured by Buyer), Sumifix Yellow GRS, Sumifix Thread B, Sumifix Tsukusu Brill Red BS, Sumifix Bril Red PB, Direct Black 40 (manufactured by Sumitomo Chemical), Dia Mirror Brown 3G, Dia Mirror Yellow G, Dia Mirror Blue 3R, Dia Mirror Bril Blue B, Dia Mirror Bril Red BB (manufactured by Mitsubishi Kasei), Remazol Red B,
Remazol Blue 3R, Remazol Yellow
GNL, Remazol Brill Green 6B (manufactured by Hoechst), Cibacron Brill Yellow, Cibacron Brill Red 4GE (manufactured by Ciba Geigy), Indico, Direct Deep Black E.
Ex, Diamine Black BH, Congo Red,
serious black, orange, amid black
10B, Orange RO, Metaneil Yellow, Victoria Scarlet, Nigrosine, Diamond Black PBB (manufactured by Ege), Diacid Blue 3G, Diacid Fast Green GW,
Diacid Milling Navy Blue R, Indanthrene (manufactured by Mitsubishi Kasei), Pomelo dye (manufactured by BASF), Orazole dye (manufactured by CIBA), Lanasin dye (manufactured by Mitsubishi Kasei), Diacryl Orange
RL-E, diacrylic brilliant blue 2B-
E, Diacrylic Turquoise Blue BG-E (manufactured by Mitsubishi Kasei), etc., 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. Pigments that can be effectively used in the present invention include many inorganic and organic pigments, and those with high infrared absorption efficiency are particularly suitable when infrared rays are used as heat conversion energy. used for. 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, cobalt oxide, barium titanate, titanium yellow, iron black, dark blue, litharge, cadmium red, Examples include silver sulfide, lead sulfate, barium sulfate, ultramarine blue, calcium carbonate, magnesium carbonate, white lead, cobalt violet, cobalt blue, emerald green, and carbon black. Most of the organic pigments are classified as dyes, which overlap with dyes in many cases, but specifically, the following are preferably used in the present invention. a Insoluble azo type (naphthol type) Brilliant Carmine BS, Lake Carmine
FB, Brilliant Fast Scarlet, Lake Red 4R, Para Red, Permanent Red R, Fast Red FGR, Lake Bordeaux 5B, Vermilion No. 1, Vermilion No.
2. Toluidine Maroon b Insoluble azo type (anilide type) Diazo Yellow, Fast Yellow G, Fast Yellow 10G, Diazo Orange, Vulcan Range, Pyrazolone Red c Soluble Azo type 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 L, Vol Maroon M d Phthalocyanine Phthalocyanine Blue, Fast Sky Blue, Phthalocyanine Green, e Dyeing lakes: Yellow lake, eosin lake, rose lake, violet lake, blue lake, green lake, sepia lake f Mordant systems: Alizarin lake, madder carmine g Vat dye system: Industhrene system, Fast Blue lake (GGS) h Basic dye lake Rhodamine lake, mafkite green lake i Acid dye lake system Fast sky blue, quinoline yellow lake, quinacridone system, dioxazine system The quantitative relationship between the above liquid and recording agent in the present invention is that the recording liquid to be prepared is In addition to being formulated to have physical properties of medium 100
The amount of recording agent is usually 1 to 50 parts, preferably 3 to 50 parts.
It is desirable to use 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, 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 problems, such as dark spots or density unevenness in the recorded image. Taking these matters into consideration, in the present invention,
The particle size of the recording agent when it is considered as a dispersion recording liquid is:
Usually 0.01-30μ, preferably 0.01-20μ, optimally
It is desirable that the thickness be 0.01 to 8μ. Furthermore, it is preferable that the particle size distribution of the dispersed recording agent be as narrow as possible, usually D±3μ, preferably D±3μ.
It is desirable that the particle diameter be 1.5μ (where D represents the average particle size). Examples of additives used in the present invention include viscosity modifiers, surface tension modifiers, PH modifiers, resistivity modifiers, wetting agents, and infrared absorbing exothermic agents. 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 to prevent the recording liquid from flowing at the discharge port of the liquid path. It is added to prevent wraparound and to prevent 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, suitable examples of the viscosity modifier include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, water-soluble acrylic resin, polyvinylpyrrolidone, gum arabic starch, and the like. In the present invention, surface tension modifiers that are appropriately selected and suitably used as desired include anionic, cationic, and nonionic surfactants. Specifically, as anionic surfactants, polyethylene Glycol ether sulfate, ester salts, etc.
Cationic systems include poly2-vinylpyridine derivatives and poly4-vinylpyridine derivatives; nonionic systems include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan monoalkyl ester, and polyoxyethylene sorbitan monoalkyl ester. Examples include oxyethylene alkylamine.
In addition to these surfactants, diethanolamine,
Aminic acids such as propanolamine and morpholinic acid, basic substances such as ammonium hydroxide and sodium hydroxide, and substituted pyrrolidones such as N-methyl-2-pyrrolidone are also effectively used. 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 used in combination 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. It is usually 0.0001 to 0.1 part by weight, preferably 0.001 to 0.01 part by weight. The PH adjuster is used 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, so as to maintain a predetermined PH value. 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 adjuster can be mentioned as long as it can control the PH value to a desired value without adversely affecting the recording liquid to be prepared. Specific examples of such PH adjusters include lower alkanolamines, monovalent hydroxides such as alkali metal hydroxides, ammonium hydroxide, and the like. 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. When recording by charging recording liquid droplets, the specific resistance of the recording liquid acts as an important factor on its charging characteristics. In other words, in order for a recording liquid droplet to be charged enough to perform good recording, the specific resistance value usually has to be
The recording liquid needs to be mixed so that it has a resistance of 10 ^-3 to 10 ¹¹ Ωcm. Therefore, in order to obtain a recording liquid having such a specific resistance value, examples of specific resistance adjusting agents that are added in the necessary amount as desired include inorganic salts such as ammonium chloride, sodium chloride, and potassium chloride, and triethanol. Specific examples include water-soluble amines such as amines and quaternary ammonium salts. In the case of recording that does not require charging of the recording liquid droplets, the specific resistance value of the recording liquid may be arbitrary. The lubricant used in the present invention is one that is more effective than those commonly known in the technical field related to the present invention, provided that the recording liquid to be prepared does not deviate from the above-mentioned physical properties. In particular, thermally stable ones are preferably used. Specific examples of such lubricants include polyalkylene glycols such as polyethylene glycol and polypropylene glycol;
alkylene glycol containing ~6 carbon atoms;
Lower alkyl ethers of diethylene glycol, such as ethylene glycol methyl ether, diethylene glycol methyl ether, and diethylene glycol ethyl ether; Glycerin; Lower alkoxy triglycols, such as methoxy triglycol and ethoxy triglycol; N
-vinyl-2-pyrrolidone oligomer; and the like. These wetting agents are added in the required amount as desired to satisfy the desired characteristics of the recording liquid, but the amount added is usually 0.1 to 10wt based on the total weight of the recording liquid. %, preferably 0.1-8wt%,
The optimum content is preferably 0.2 to 7 wt%. 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 necessary amounts of the above-mentioned additives as desired, and the recording liquid has excellent formation properties and film strength when attached to a recording member. For example, resin polymers such as alkyd resins, acrylic resins, acrylamide resins, polyvinyl alcohol, polyvinylpyrrolidone, etc. may be added in order to obtain the same. In the present invention, when electromagnetic wave energy, particularly infrared rays, is used, it is desirable to add an infrared absorbing exothermic agent to the recording liquid in order to make the action of the energy more effective. Most of the infrared absorbing exothermic agents are included in the above-mentioned recording materials, but dyes and pigments with high infrared absorbance are particularly suitable.Specifically, examples of dyes include water-soluble nigrosine, modified water-soluble Nigrosine, alcohol-soluble nigrosine that can be made water-soluble, etc., as pigments, inorganic pigments such as carbon black, ultramarine, cadmium yellow, red iron, chrome yellow, etc.
Preferred examples include organic pigments such as azo, triphenylmethane, quinoline, anthraquinone, and phthalocyanine pigments. In the present invention, when the infrared absorbing exothermic agent is added separately from the recording agent, the amount of the infrared absorbing exothermic agent added is usually 0.01 to 10 wt%, preferably 0.1% based on the total weight of the recording liquid.
It is desirable that it be ~5wt%. Especially if it is insoluble in the liquid medium used,
Depending on the particle size when dispersed, there is a risk of sedimentation, agglomeration, and nozzle clogging during storage or stagnation of the recording liquid, so it is recommended to keep the amount to a minimum within the range that provides a noticeable effect. desirable. The recording liquid used in the present invention has specific heat, coefficient of thermal expansion, thermal conductivity, viscosity, surface tension, pH, and charged recording liquid droplets in order to have the various recording properties described above. In the case of recording, the composition is adjusted so that characteristic values such as specific resistance fall within a specific range of conditions. In other words, these physical properties are the stability of the stringing phenomenon,
In the present invention, when preparing the recording liquid, it is important to note that the recording liquid , it is necessary to pay sufficient attention to these matters. The above-mentioned physical properties of the recording liquid that can be effectively used in the present invention are preferably as shown in Table 1 below. It is not necessary to satisfy the numerical conditions as shown, and it is sufficient that some of these physical properties take values that satisfy the conditions in Table 1, depending on the required recording characteristics. However, regarding specific heat, coefficient of thermal expansion, thermal conductivity, viscosity, and surface tension,
The values in the table need to be specified. Of course, it goes without saying that the more of the above-mentioned physical properties of the prepared recording liquid that satisfy the values shown in Table 1, the better the recording will be.

[Table] Condition Example 1 Image recording was carried out using the apparatus schematically shown in FIG. In FIG. 2, the nozzle 99 is installed at its tip in contact with the heat generating part of the electrothermal converter 100, and at one end there is a pump for supplying recording liquid into the nozzle 99. 101 are connected. 102 pumps recording liquid from a recording liquid storage tank (not shown) to pump 101;
This is a pipe to send advice to. Electrothermal converter 10
0, in order to vary the position where thermal energy is applied to the nozzle 99, six heating elements (not visible in the drawing at the bottom of the nozzle 99) are independently attached in the direction of the central axis of the nozzle 99. A selection electrode 103 (A ₁ , A ₂ , A ₃ , A ₄ , A ₅ , A ₆ ) and a common electrode 104 are connected to the heating element. Reference numeral 105 is a rotatable drum on which the recording member is attached and rotated, and the scanning speed of the nozzle 99 and its rotation speed are arranged to have appropriate timing. The recording liquid used for image recording was Black 17-1000 (trade name, manufactured by ABDick), and had the physical properties described above. The recording conditions are shown in Table 2. Table 3 shows the spot diameters on the recording liquid on the recording member obtained when image recording was performed by driving each heating element of the electrothermal converter 100. From the results shown in Table 3, it was found that by changing the position of thermal energy application of the nozzle 99, it was possible to change the spot diameter of the recording liquid formed on the recording member. Next, the electrothermal converter 100 is driven so that a signal corresponding to the input signal of one of the six heating elements is inputted to a predetermined heating element according to the input level of the recording information signal. When an image was recorded, an image with extremely excellent gradation and clear image quality was obtained.

【table】

[Table] Example 2 A clear image was obtained when image recording was carried out using the printer device schematically shown in FIG. In FIG. 3, 106 is a recording head, which is an ejection opening (orifice) for ejecting recording liquid.
The electrothermal converter 107 includes a nozzle 108 and an electrothermal converter 107 surrounding a part of the nozzle 108. The recording head 106 is connected to the pipe fitting 1
At 09, it is connected to a pump 110 for supplying the recording liquid to the nozzle 108, and the recording liquid is transported to the pump 110 from the direction of the arrow in the figure. Reference numeral 111 denotes a charging electrode for charging recording liquid droplets ejected from the ejection opening of the nozzle 108 according to a recording information signal, and 112a and 112b deflect the flying direction of the charged recording liquid droplets. It is a deflection electrode. 113 is a gutter for collecting recording liquid droplets unnecessary for recording, and 114 is a recording member. The recording liquid used to record images was
This was an ink for CasioC.JP, and the recording liquid had the physical property values described above. The recording conditions are shown in Table 4.

[Table] Example 3 The apparatus used in this example will be explained with reference to FIG. FIG. 4 is a schematic perspective view for explaining the configuration of the device used in this example. In the figure, a laser beam emitted by a laser oscillator 115 is guided to an entrance aperture of an acousto-optic modulator 116. In the modulator 116, the laser beam is modulated in intensity according to the input of the recording information signal to the modulator 116. The optical path of the modulated laser beam is refracted toward the beam expander 118 by the reflected light 117 and enters the beam expander 118 . The beam diameter of the modulated laser beam is expanded by the beam expander 118 while it remains a parallel beam. Next, the laser beam whose beam diameter has been expanded is the polygon 11.
9. The polygon 119 is attached to the rotating shaft of a hysteresis synchronous motor 120 and rotates at a constant speed. The laser beam horizontally swept by the polygon 119 is imaged by an f-theta lens via a reflecting mirror 122 onto a predetermined position of each nozzle of a nozzle array 124 aligned at the tip of a multi-nozzle recording head 123. Due to the image formation of the laser beam on the nozzle array 124, the recording liquid in each nozzle is affected by thermal energy, and small droplets of the recording liquid are ejected from the nozzle ejection ports and recorded on the recording member 125. It will be done. Recording liquid is supplied to each nozzle of the recording head 123 via a transport pipe 126. The recording head 123 used in this example had a nozzle array with a total length of 20 cm, a number of nozzles/mm, and an ejection opening diameter of about 40 μm. Other recording conditions are shown in Table 5, and the recording liquid used is shown below.

[Table] Recording liquid: 1 part by weight of alcohol-soluble nigrosine dye (Spirit Black SB manufactured by Orient Chemical Co., Ltd.) was added to 4 parts by weight of ethylene glycol and mixed and dissolved. 60 parts by weight of this solution was poured into 94 parts by weight of water containing 0.1 w% dioxin (trade name) and thoroughly stirred. The solution thus obtained was filtered twice using a Millipore filter with an average pore size of 10 μm to obtain an aqueous recording liquid. The recording liquid was prepared to have the various physical properties described above. Example 4 In this example, image recording was performed using a multi-nozzle recording head 127 schematically shown in a partial perspective view in FIG. Referring to FIG. 5, the recording head 127
is the discharge port (orifice) for discharging the recording liquid.
A large number of nozzles 128 having
A common recording liquid supply chamber 134 is connected to each nozzle. Recording liquid is supplied to the recording liquid supply chamber 134 from the direction of the arrow in the figure through a feed pipe 135. Now, FIG. 6 shows a partial sectional view taken along the dotted line X''Y'' in FIG. 5. An electrothermal converter 136 is attached to the surface of the nozzle 128 independently for each nozzle. The electrothermal converter 136 includes a heating element 137 on the surface of the nozzle 128 and electrodes 13 at both ends of the heating element 137.
8, 139, a common lead electrode 140 common to each nozzle from the electrode 138, a selective lead electrode 141 from the electrode 139, and an oxidation-resistant film 142. 143, 144 are electrically insulating sheets, 145,
146, 147, and 148 are rubber cushions for preventing mechanical damage to the nozzle 128. Now, when a signal corresponding to recording information is input to the electrothermal converter 136, the heating element 137 generates heat, and the state of the recording liquid 149 in the nozzle 128 changes due to the action of the thermal energy, causing the nozzle 128 to change its state. A small droplet 150 of recording liquid is ejected from the orifice and adheres to the recording member 151 to perform recording. Table 6 shows the recording conditions in this example. The recorded images obtained in this example were also extremely clear and of good quality. The average spot diameter of the recorded images was approximately 60μ.

【table】

[Table] Examples 5 to 9 Using the recording liquids shown below (No. 5 to No. 9) prepared to have the various physical property values described above,
When images were recorded using the recording apparatus shown in FIG. 2, images of extremely excellent quality were obtained on plain paper in all cases.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram for explaining the outline of an inkjet recording method to which the recording liquid of the present invention is applied, and FIGS. 2 to 4 show the configuration of the recording apparatus used in this embodiment. A schematic perspective view, FIG. 5 is a partial perspective view showing the configuration of the recording head of the recording device used in this embodiment, and FIG. 6 is a schematic perspective view of FIG.
It is an X″Y″ cross-sectional view. 1... Nozzle (liquid path), 2... Orifice (discharge port), 3... Recording liquid, 4... Recording member, 5...
...Droplets.

Claims (1)

[Claims] 1. Using thermal energy, the recording liquid supplied to a liquid path is ejected from an ejection port communicating with the liquid path to form flying droplets to perform recording. In the recording liquid for inkjet recording, the liquid medium and 1 part by weight per 100 parts by weight of the liquid medium are added.
Contains ~50 parts by weight of recording agent and additives, has a specific heat of 0.1 to 4.0 J/gk, and a coefficient of thermal expansion of 0.1×10 ^-3 to 1.8×
10 ^-3 deg ^-1 , thermal conductivity 0.1×10 ^-3 ~ 50×10 ^-3 W/
A recording liquid for inkjet recording using thermal energy, characterized by having a viscosity of 0.3 to 30 cps and a surface tension of 10 to 60 dyne/cm at cm/deg and 20°C. 2 Claim 1, wherein the recording agent is a dye
A recording liquid for inkjet recording that utilizes thermal energy as described in 2. 3 Claim 1 in which the recording agent is a pigment
A recording liquid for inkjet recording that utilizes thermal energy as described in 2. 4. The recording liquid for inkjet recording using thermal energy according to claim 3, wherein the pigment has a particle size distribution of D±3μ (where D is the average particle size). 5 The additive is 0.1% of the total weight of the recording liquid.
The recording liquid for inkjet recording using thermal energy according to claim 1, which is a wetting agent containing ~10 wt%. 6 The additive is added to 1 part by weight of the recording liquid.
The recording liquid for inkjet recording using thermal energy according to claim 1, which contains a surface tension adjusting agent in an amount of 0.0001 to 0.1 part by weight. 7. The recording liquid for inkjet recording using thermal energy according to claim 1, wherein the additive is a viscosity modifier. 8. The recording liquid for inkjet recording using thermal energy according to claim 1, wherein the additive is an infrared absorbing exothermic agent. 9. The recording liquid for inkjet recording using thermal energy according to claim 8, wherein the infrared absorbing exothermic agent is contained in an amount of 0.01 to 10 wt% based on the total weight of the recording liquid.