JP2825862B2 - Liquid jet recording head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid jet recording head, and more particularly, to a recording head of a thermal ink jet printer.

2. Description of the Related Art Non-impact recording methods have recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Among them, the so-called ink jet recording method, which can perform high-speed recording and can perform recording on so-called plain paper without requiring a special fixing process, is an extremely powerful recording method. Some have been proposed and commercialized with improvements, while others are still being put to practical use.

In such an ink jet recording method, recording is performed by flying droplets of a recording liquid called so-called ink and attaching the droplets to a recording member. The control method for controlling the flying direction of the generated recording liquid droplet is roughly classified into several types.

First, the first method is disclosed in, for example, US Pat. No. 3,060,429 (Tele type method),
Recording liquid droplets are generated by electrostatic attraction, and the generated recording liquid droplets are subjected to electric field control according to a recording signal, and recording is performed by selectively adhering the recording liquid droplets onto a recording member. It is.

More specifically, in more detail, an electric field is applied between the nozzle and the accelerating electrode to discharge a uniformly charged droplet of the recording liquid from the nozzle, and the discharged droplet of the recording liquid is converted into a recording signal. In accordance with this, recording is performed by causing the droplets to fly between the xy deflection electrodes configured so as to be electrically controllable and selectively adhering small droplets onto the recording member by a change in the intensity of the electric field.

The second method is described, for example, in US Pat. No. 3,596,275,
The method disclosed in US Pat. No. 3,298,030 and the like (S
Weet method) in which droplets of the recording liquid with a controlled charge amount are generated by a continuous vibration generation method, and the generated droplets with a controlled charge amount are subjected to a uniform electric field. The recording is performed on the recording member by flying between the deflection electrodes.

More specifically, a charging electrode configured so that a recording signal is applied in front of an orifice (ejection port) of a nozzle, which is a part of a recording head provided with a piezoelectric vibrating element, is separated by a predetermined distance. The piezoelectric vibrating element is mechanically vibrated by applying an electric signal of a constant frequency to the piezoelectric vibrating element, and a droplet of the recording liquid is discharged from the discharge port. At this time, a charge is electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with a charge amount according to the recording signal. When the droplet of the recording liquid whose charge amount is controlled flies between the deflection electrodes to which a constant electric field is uniformly applied, the droplet is deflected according to the added charge amount and carries a recording signal. Only the recording material can be deposited on the recording member.

The third method is a method (Hertz method) disclosed in, for example, US Pat. No. 3,416,153, in which an electric field is applied between a nozzle and a ring-shaped charging electrode, and a continuous vibration generation method is used. This is a method in which small droplets are generated and atomized for recording. That is, in this method, the atomization state of the small droplet is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the image is recorded with the gradation of the recorded image.

The fourth system is, for example, a system (Stemme system) disclosed in US Pat. No. 3,747,120, and this system is fundamentally different from the above three systems in principle.

That is, in each of the three methods, the droplet of the recording liquid discharged from the nozzle is electrically controlled during the flight, and the droplet carrying the recording signal is selectively attached to the recording member. On the other hand, according to the Stemme method, recording is performed by ejecting a small droplet of recording liquid from an ejection port in accordance with a recording signal.

That is, in the Stemme method, the piezoelectric vibrating element attached to the recording head having the ejection port for ejecting the recording liquid includes:
Applying an electrical recording signal, converting the electrical recording signal into mechanical vibration of a piezo-vibrating element, and ejecting a droplet of the recording liquid from the ejection port in accordance with the mechanical vibration to cause the droplet to fly and adhere to the recording member. Is to record.

Each of these four conventional methods has its own features, but on the other hand, there are points that can be solved.

That is, in the first to third methods, the direct energy of the generation of the droplet of the recording liquid is electrical energy,
The control of the deflection of the droplet is also the electric field control. Therefore, the first method is simple in structure, but requires a high voltage to generate small droplets, and is not suitable for high-speed printing because it is difficult to use a multi-nozzle recording head.

The second method is suitable for high-speed recording because it is possible to use a multi-nozzle recording head. However, the configuration is complicated, and the electrical control of the recording liquid droplets is advanced and difficult. There is a problem that satellite dots easily occur.

The third method has a feature that an image having excellent gradation can be recorded by atomizing a recording liquid droplet, but on the other hand, it is difficult to control the atomization state, and fogging occurs in the recorded image. In addition, there are problems such as the fact that it is difficult to use a multi-nozzle recording head, and it is not suitable for high-speed recording.

The fourth scheme has relatively many advantages over the first to third schemes. That is, in order to perform recording by discharging the recording liquid from the discharge port of the nozzle on demand (on-demand), it is simple in terms of the configuration. It is not necessary to collect small droplets that are not required for recording an image, and there is no need to use a conductive recording liquid as in the first and second methods, and the recording liquid material Has a great advantage such as a large degree of freedom. However, on the other hand, it is difficult to form a multi-nozzle recording head because there are problems in processing the recording head and it is extremely difficult to reduce the size of the piezoelectric vibrating element having a desired resonance number. However, since the recording liquid droplets are ejected and fly by the mechanical energy of mechanical vibration of the piezo-vibration element, it is not suitable for high-speed recording.

Further, Japanese Patent Application Laid-Open No. 48-9622 (the aforementioned U.S. Pat.
No. 120) describes, as a modification, the use of thermal energy instead of the mechanical vibration energy by means such as the piezo-vibration element.

That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording apparatus which uses a heating coil for directly heating a liquid as a pressure increasing means instead of a piezo vibrating element in order to generate vapor which causes a pressure increase. I have.

However, the above publication discloses that a heating coil serving as a pressure increasing means is energized to directly evaporate the liquid ink in a bag-shaped ink chamber (liquid chamber) having only one opening through which the liquid ink can enter and exit. However, there is no suggestion as to how to heat the liquid when the liquid is continuously and repeatedly discharged. In addition, since the position where the heating coil is provided is provided at the deepest part of the bag-shaped liquid chamber far from the supply path of the liquid ink, in addition to being complicated in terms of the head structure, continuous It is not suitable for repeated use.

Moreover, according to the technical contents described in the above-mentioned publication, it is not possible to quickly form a preparation state for the next liquid discharge after performing the liquid discharge with the generated heat which is practically important.

As described above, the conventional method has advantages and disadvantages in terms of configuration, high-speed recording, multi-nozzle recording head, generation of satellite dots and occurrence of fogging of a recorded image, etc. There was a restriction that only the application was possible.

Japanese Patent Application Laid-Open No. 55-82663 discloses that the temperature of the surface of a heating element can be rapidly decreased by cooling the heating element substrate, and the heating of the recording medium liquid around the vapor bubbles is reduced to thereby dissolve dissolved oxygen or the like. It is described that the frequency response of the heating element itself is also improved while the frequency response of the droplets is improved by suppressing the generation of bubbles generated from the air bubbles, and furthermore, JP-A-61-211045. In the publication, a heater and a temperature detecting means are provided in the print head unit, and a blower is provided in the apparatus.
It is described that by controlling the driving of the heater and the blower based on a detection signal of the temperature detecting means, the temperature of a print head portion is maintained in a proper ink droplet forming range. Further, as an application prior to the present invention, a recording head, particularly an invention relating to a layer structure of a heating element substrate and its material has been filed, but the heat transfer characteristics of the recording head as in the present invention are described. Not been.

To improve the heat transfer characteristics of the recording head, Japanese Patent Application Laid-Open
In Japanese Unexamined Patent Publication No. 82663, a very large heat sink for heat radiation cooling is used, and in Japanese Unexamined Patent Publication No. 61-211045, cooling is performed using a blower. However, these methods are all disadvantageous in terms of compactness and cost due to the large configuration of the apparatus. This is just
This was caused by trying to achieve the purpose by easily providing a cooling device in the recording head without sufficiently examining the heat transfer characteristics of the recording head from the structural point of view.

Japanese Patent Application Laid-Open No. 55-128468 discloses the following as a protective layer of an electric / heat converter of a bubble jet head. In other words, titanium oxide,
Transition metal oxides such as vanadium oxide, niobium oxide, molybdenum oxide, tantalum oxide, tungsten oxide, chromium oxide, zirconium oxide, hafnium oxide, lanthanum oxide, yttrium oxide, and manganese oxide, as well as aluminum oxide, calcium oxide, strontium oxide, and oxide Metal oxides such as barium and silicon oxide, and composites thereof. Silicon nitride, aluminum nitride, boron nitride,
High resistance nitrides such as tantalum nitride and composites of these oxides and nitrides, as well as semiconductors such as amorphous silicon and amorphous selenium, which have low resistance in bulk, are subject to sputtering, CVD, vapor deposition, gas phase reaction, In general, a thin film that increases resistance during manufacturing processes such as liquid coating
The film is formed to a thickness of m to 5 μm, preferably 0.2 μm to 3 μm.

Separately, physical properties such as good film formability, dense structure and few pinholes, no swelling or dissolution in the ink used, good insulation when formed, high heat resistance, etc. Such as silicone resin, fluorine resin, aromatic polyamide, addition polymerization type polyimide, polybenzimidazole, metal chelate polymer, titanate, epoxy resin, phthalic resin, thermosetting phenol resin, P- A protective layer can be formed by forming a film of a vinylphenol resin, a Xyloc resin, a triazine resin, a BT resin (triazine resin and a bismaleimide addition polymerization resin), or the like. In addition, there is a method of depositing a polyxylylene resin and its derivative by vapor deposition.

Further, various organic compound monomers such as thiourea, thioacetamide, vinyl ferrocene, 1,3,5-trichlorobenzene, chlorobenzene, styrene, ferrocene, picoline, naphthalene, pentamethylbenzene,
Nitrotoluene, acrylonitrile, diphenyl selenide, P-toluidine, P-xylene, N, N-dimethyl-P-toluidine, toluene, aniline, diphenyl mercury, hexamethylbenzene, malononitrile,
Tetracyanoethylene, thiophene, benzeneselenol, tetrafluoroethylene, ethylene, N-nitrosodiphenylamine, acetylene, 1,2,4-trichlorobenzene, propane can be formed into a protective layer by plasma polymerization. it can.

As described above, Japanese Patent Application Laid-Open No. 55-128468 proposes various materials for the protective layer. However, diamond-like carbon (also called i-carbon, amorphous carbon, diamond thin film)
There is no example in which is used as a material for the protective layer. In a bubble jet type ink jet, typical characteristics required for a protective layer for protecting a heating element include, for example, strong corrosion resistance so that the heating element is not corroded by ink, and heat generated by the heating element. To be able to transfer to ink efficiently,
High thermal conductivity. The present inventors have quickly discovered that diamond-like carbon, which has attracted attention in recent years, is an optimal material that satisfies this property, and proposes to apply it to a protective layer of a bubble jet type ink jet. It is.

Object The present invention has been made in view of the above-mentioned circumstances, and by sufficiently examining the heat transfer characteristics of the recording head from the structural aspect, it is possible to sufficiently radiate heat without providing a special external cooling device. It is an object of the present invention to provide a head structure with high ejection efficiency, in which heat generated by a heat generating element is cooled and efficiently transmitted to ink, and bubbles are instantaneously generated.

Configuration In order to achieve the above object, the present invention provides a thermal energy acting section that accommodates a recording liquid to be introduced, generates bubbles from the recording liquid by heat, and generates an acting force accompanying an increase in the volume of the bubbles. And an orifice for communicating with the flow path to discharge the recording liquid as droplets by the action force, and communicating with the flow path to introduce the recording liquid into the flow path. A liquid chamber for
In the liquid jet recording head comprising means for introducing the recording liquid into the liquid chamber, an isothermal line on a vertical surface of the heating element substrate including a center line of the flow path turns off a driving pulse of the heating element. The thermal physical property value and the density of the material constituting the thermal energy acting portion are determined so as to extend not to the orifice side but to the liquid chamber side with respect to the heating element when the heating element is used as a reference. It is.

FIG. 5 is a diagram for explaining the principle of ink ejection by a bubble jet to which the present invention is applied, FIG. 6 is a perspective view of a bubble jet recording head, and FIG. 7 is an exploded configuration diagram of the recording head. FIG. 8A is a rear view of the lid substrate shown in FIG. 7A, and FIG. 8B is a rear view of the lid substrate shown in FIG. 7A. 72 is a heating element substrate, 73 is a recording liquid inlet, 74 is an orifice, 75 is a flow path, 76 is a region for forming a liquid chamber, 77 is a selection electrode, 78 is a common electrode,
79 is a heating element, 80 is ink, 81 is air bubbles, and 82 is flying ink droplets.

(A) is a steady state in which the surface tension of the ink 80 and the external pressure are in an equilibrium state at the orifice surface.

7B shows a state in which the heater 79 is heated until the surface temperature of the heater 79 rises rapidly and boiling development occurs in the adjacent ink layer, and minute bubbles 81 are scattered.

(C) shows a state in which the adjacent ink layer heated rapidly on the entire surface of the heater 79 is instantaneously vaporized to form a boiling film, and the bubbles 81 grow. At this time, the pressure in the nozzle rises by an amount corresponding to the growth of the bubble, the balance with the external pressure on the orifice surface is lost, and the ink column starts to grow from the orifice.

(D) is a state in which the bubble has grown to the maximum, and the ink 80 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 79, and the surface temperature of the heater 79 is decreasing. The maximum value of the volume of the bubble 81 is slightly delayed from the timing of applying the electric pulse.

(E) shows a state where the bubble 81 is cooled by ink or the like and starts to contract. At the front end of the ink column, the ink moves forward while maintaining the pushed speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to a decrease in the nozzle internal pressure due to the contraction of the bubble, and the ink column is constricted. .

In (f), the bubble 81 is further contracted, the ink comes into contact with the heater surface, and the heater surface is more rapidly cooled. At the orifice surface, the external pressure becomes higher due to the internal pressure of the nozzle, so that the meniscus largely enters the nozzle. The tip of the ink column becomes a droplet and moves in the direction of the recording paper.
Flying at a speed of 10m / sec.

In (g), in the process in which the ink is supplied (refilled) to the orifice again by capillary action and returns to the state of (a), the bubbles have completely disappeared.

 Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a vertical cross-sectional view of a substrate including a center line of a flow path near a heating element portion of a heating element substrate used in the present invention,
FIG. 2 is a view for explaining a manufacturing process of the heating element substrate shown in FIG. 1. In the drawing, 11 is a heating resistance layer, 12 is a heating element protection layer, 13 is an electrode protection layer, and 14 is a second protection layer. Electrodes (individual electrodes), 15
Is a first electrode (common electrode), 16 is a heat storage layer, 17 is an insulating layer,
18 is a base substrate and 20 is ink.

First, when Si is used as the substrate material 18, a thermal oxide film is formed on its surface, for example. As a substrate material, it is also possible to use an alumina substrate with a glaze layer, which is often used in technology such as a thermal head. Both the SiO ₂ film on the silicon substrate and the glaze layer (the composition is the same as glass) on the alumina substrate work as the heat storage layer 16. The SiO ₂ film may be formed by CVD or by a technique such as sputtering, in addition to thermal oxidation.

(A) Next, a first electrode 15 is formed, and (b) an insulating layer 17 is formed on this electrode except for at least a place where a lead wire is taken out and a place where a heating resistance layer 11 described later is connected. Provided.

As the material constituting the electrode, many commonly used electrode materials are effectively used, and specific examples include Al, Ag, Au, Pt, and Cu. It is provided at a predetermined position in a predetermined size, shape and thickness by a technique such as vapor deposition.

Further, as a material constituting the insulating layer, SiO ₂ , Si ₃ N ₄
Are used. These are also formed by using the above-described methods such as sputtering, CVD, and photolithography technology, and etching technology, and have a thickness of 0.1.
A value of about 10 μm is preferably used.

(C) Next, the heating resistance layer 11 is provided so as to be connected to the first electrode 15.

As the useful material constituting the heating resistor, for example, a mixture of tantalum -SiO _2, tantalum nitride, nichrome, silver - palladium alloy, silicon semiconductor or hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum , Niobium, chromium, vanadium and the like.

Among these materials forming the heating resistor, metal borides can be particularly excellent, and among them, hafnium boride has the most excellent characteristics.
Next are zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride.

The heating resistor can be formed using the above-mentioned materials by a technique such as electron beam evaporation or sputtering. The film thickness of the heating resistor is determined according to its area, material, shape and size of the heat acting portion, and furthermore, actual power consumption, etc., so that the amount of heat generated per unit time is as desired. Is usually 0.001 to 5 μm,
Preferably, it is 0.01 to 1 μm.

(D) Next, the second electrode 14 is formed. Note that the order of forming the heating resistor layer 11 and the second electrode 14 may be reversed, and the second electrode 14 may be inserted under the heating resistor layer 11 at a connection portion therebetween.

(E) Next, the heating element protection layer 12 is formed. The characteristic required for the heating element protection layer 12 is to protect the heating resistor from the recording medium without preventing the heat generated by the heating resistor from being effectively transmitted to the recording liquid.

Useful materials for the protective layer include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, tantalum (Ta), and the like. It can be formed using a technique. As will be described later, diamond-like carbon can be given as a suitable material. The thickness of the protective layer is usually 0.
01-10 μm, preferably 0.1-5 μm, optimally 0.1-3 μm
m is desirable.

(F) Further, in order to protect the second electrode 14 from the ink 20, an electrode protection layer 13 is provided.

It is desirable to use an organic material that is extremely easy to perform fine photolithography processing if a high-density multi-orifice type recording head is to be formed, which is useful as a material forming the electrode protection layer 13. Specific examples of such an organic material include, for example, polyimide isoindoloquinazolinedione (trade name: PIQ, manufactured by Hitachi Chemical), polyimide resin (trade name: PYRALIN, manufactured by Dupont), cyclized polybutadiene (trade name: JSR-CBR, CBR-M 9
01. Nippon Synthetic Rubber), Photo Nice (trade name: manufactured by Toray), and other photosensitive polyimide resins are preferred.

In the print head of the present invention manufactured by the above-described method, the heat radiation cooling of the heat generated by the heat generating element is a key that affects the ink ejection performance.

The present invention is based on repeated simulations, trial production of heads, and evaluation of ink discharge performance, and focuses on the fact that a head exhibiting the following heat radiation and cooling characteristics has excellent ink discharge performance. That is, it is a preferable condition of the recording head that the heat generated by the heating element escapes promptly instead of staying in the vicinity of the heating element. Further, with regard to the way of escaping heat, it is a more preferable condition for the head to escape to the liquid chamber side instead of the orifice side.

FIGS. 3 (a) and 3 (b) show typical examples of the preferred embodiment of the present invention and FIGS. 4 (a) and 4 (b), respectively. , 31; 41, 51 are heating resistance layers, 22, 32; 42, 52 are heating element protective layers, 23, 33; 43, 53
Is an electrode protective layer, 24, 34; 44, 54 are second electrodes, 25, 35; 45, 55
Is the first electrode (common electrode), 26,36;
37; 47, 57 is an insulating layer, 28, 38; 48, 58 is a base substrate, 29, 39; 4
9, 59 is an isothermal line, and 30, 40; 50, 60 are inks. In these figures, reference numerals 29 and 39 denote temperature distributions near the heating element immediately after the driving energy was cut off after the driving energy was applied to the heating element for 5 μsec. It is shown by. In the case of FIG. 3, it can be read from this that the generated heat quickly escapes to the liquid chamber side, and in the case of FIG. 4, the heat either stays near the heating element or escapes to the orifice side. You can read the situation. This heat transfer, that is, heat radiation and cooling, has a great effect on the maximum response frequency during continuous ejection as the ink ejection performance of the head. In the case of FIG. 3, the maximum response frequency is fomax = 5.2 KHz, In the case of the figure, fomax = 0.6 KHz. The orifice dimensions were both 20 μm, and the ink used was an aqueous ink (pH = 9.8). In the case of FIG. 3, the ratio of the thermal conductivity between the base substrate and the heat storage layer was 70: 1, and in the case of FIG. 4, it was 3: 1.

 Table 1 shows other examples.

As is apparent from the above, according to these embodiments, the recording head having a configuration in which the heat generated by the heating element escapes to the liquid chamber side instead of to the orifice side, or the generated heat is completely eliminated. It can be seen that the recording head having a configuration that quickly escapes to the liquid chamber has excellent heat radiation and cooling characteristics, a high maximum response frequency, and is suitable for high-speed printing.

In the present invention, the electrode protective layer 12 is preferably made of diamond-like carbon as described above. Various methods for synthesizing diamond-like carbon have been proposed so far, but they can be roughly classified into:-Ion beam deposition (IBD) method-Chemical vapor deposition (CVD) method-Plasma CVD method . Here, the plasma CVD method experimentally manufactured by the present inventors will be described as an example.

First, a sample in which a heat storage layer (SiO ₂ ), a heating element, electrodes, etc. were formed on a silicon substrate was attached to the RF power supply side in a vacuum device, and hydrocarbons (CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₄ H _10, C ₂ in H _4, etc.) consisting of a hydrogen gas atmosphere, high frequency electric field parallel plate electrodes (1
When 3.56 MHz is applied, a glow discharge is generated, the source gas is decomposed into radicals and ions, and a hard carbon film (diamond-like carbon) composed of carbon atoms and hydrogen atoms is deposited on the sample. Table 2 shows the deposition conditions, and Table 3 shows the physical properties of the film at that time.

Under the above conditions, the diamond-like carbon protective layer
12 is usually 0.01 to 10 μm, preferably 0.05 to 5 μm,
Optimally, the thickness is desirably 0.05 to 3 μm. Tables 4-1 to 4-4 show the thermal conductivity of various substances described in the science chronological table. Compared to these, it can be seen that the thermal conductivity of diamond-like carbon is very high, and that it is optimal as a protective layer for a heating element of a bubble jet ink jet that requires instantaneous heat conduction.

Table 5 shows an example of the performance comparison of a bubble jet head in which a SiO ₂ film and a diamond-like carbon film, which are more often used than before, are used as protective layers, respectively.

Even at the response frequency (Max value), the durability (life fo
= 3 KHz), it can be seen that the case where the diamond-like carbon was used as the protective layer was more excellent.

The recording liquid used in the recording apparatus according to the present invention is used in the conventional recording method in addition to the selection of the material and the ratio of the composition components so as to have a thermophysical property value and other physical property values described later. In addition to being chemically and physically stable like the recording liquid, it has excellent responsiveness, fidelity, and spinning ability, does not harden at the liquid path, especially at the discharge port, and responds to the recording speed in the flow path. The physical properties are adjusted so as to give characteristics such as being able to circulate at a high speed, fast fixing to a recording member after recording, sufficient recording density, and good storage life.

The recording liquid used in the recording apparatus according to the present invention is composed of a liquid medium, a recording agent that forms a recording image, and an additive that is added to obtain desired characteristics. Any of aqueous, non-aqueous, soluble, conductive, and insulating can be obtained by selecting the type of the additive and the composition ratio of the additive.

The liquid medium is roughly classified into an aqueous medium and a non-aqueous medium, and the liquid medium used is a combination with other selected components such that the recording liquid whose physical properties are adjusted has the above-mentioned physical properties. Is selected in consideration of the following.

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, pentyl alcohol, hexyl alcohol, heptyl alcohol , Octyl alcohol, nonyl alcohol, alkyl alcohols having 1 to 10 carbon atoms such as decyl alcohol; for example, hydrocarbon solvents such as hexane, octane, cyclopentane, benzene, toluene and xylol; for example, carbon tetrachloride, trichloroethylene,
Halogenated hydrocarbon solvents such as 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, methyl propyl ketone, methyl amyl ketone , Cyclohexanone and the like; ketone solvents such as ethyl formate, methyl acetate, propyl acetate, phenyl acetate and ethylene glycol monoethyl ether acetate; alcohol solvents such as diacetone alcohol; petroleum hydrocarbon solvents and the like. Can be

These enumerated liquid media are appropriately selected and used so as to satisfy the affinity for a recording agent or an additive to be used and various properties described below as a recording liquid. If necessary, two or more kinds may be mixed and used within a range in which a recording liquid having characteristics can be prepared. Further, these non-aqueous media and water may be mixed and used under the above conditions.

Among the above liquid media, water or a water-alcohol-based liquid medium is preferable in consideration of pollution, availability, ease of preparation, and the like.

As the recording agent, the recording liquid to be prepared has the above-mentioned various physical property values, sedimentation and coagulation in a liquid path or a recording liquid supply tank after being left for a long time, and further, a transport pipe or a liquid path. It is necessary to select and use materials in relation to the liquid medium and additives so as not to cause clogging. From such a point, it is preferable to use a recording agent that is soluble in the liquid medium, but even if the recording agent is dispersible or hardly soluble in the liquid medium, the particles of the recording agent when dispersed in the liquid medium are used. It can be used if the diameter is made sufficiently small.

The recording agent that can be used is appropriately selected depending on the recording member so as to sufficiently meet the recording conditions. Dyes and pigments can be mentioned as recording agents. Dyes to be used effectively are those which can satisfy the following properties of the prepared recording liquid, and are preferably used, for example, direct dyes as water-soluble dyes, basic dyes, and acid dyes. In addition to dyes, soluble vat dyes, acid mordant dyes, mordant dyes, sulfur dyes as water-insoluble dyes, vat dyes, liquor dyes, oil-soluble dyes, disperse dyes, etc., sllen dyes, naphthol dyes, and reactions Dye, chrome dye, 1: 2 type complex salt dye, 1: 1 type complex salt dye,
It is selected from azoic dyes, cationic dyes and the like.

Specifically, for example, Resoring Lil Blue PRL, Resorin Yellow PCG, Resorin Pink PRR, Resorin Green PB (manufactured by Buyer), Sumicaron Blue S-BG, Sumicaron Red E-EBL, Sumicaron Yellow E-4GL ,
Sumicaron Brilliant Blue S-BL (Sumitomo Chemical), Dyanix Yellow-HG-SE, Dyanic Thread BN-SE (Mitsubishi Chemical), Kayaron Polyester Light Flavin 4GL, Kayaron Polyester Blue 3
R-SF, Kayaron Polyester Yellow YL-SE, Kayaset Turkey 776, Kayaset Yellow 902, Kayaset Red 026, Prosion Red H-2B, Prosion Blue H-3R (all manufactured by Nippon Kayaku), Levafix Golden Yellow PR, Levafix Brill Red PB, Levafix Brill Orange P-GR (all made by buyers), Sumifix Yellow GRS, Sumifix B, Sumifix Brill Red BS, Sumifix Brill Blue PB, Direct Black 40 (Sumitomo Chemical), Diamond Mirror Brown 3G, Diamond Mirror Yellow G, Diamond Mirror Blue 3R, Diamond Mirror Brill Blue B, Diamond Mirror Brill Red BB (Mitsubishi Chemical), Remazol Red B, Remazol Blue 3R , Remazol Yellow GNL, Remazol Brillg 6B (from Hoechst), Cibacron Brill Yellow, Cibacron Brill Red 4GE (from Ciba Geigy), Indico, Direct Tape Black E / Ex, Diamine Black BH, Congo Red, Serious Black BH, Orange II , Amido Black 10B, Orange RO, Metanil Yellow, Victoria Scarlet, Nicrosin, Diamond Black PBB (all manufactured by EAG), Diacid Blue 3G, Diacid Fast Green GW, Diacid Milling Navy Blue R, Indanthrene ( Above dyes (manufactured by Mitsubishi Kasei), savon-dye (manufactured by BASF), orazole dye (manufactured by CIBA), lanassin dye (manufactured by Mitsubishi Chemical),
Die Acrylic Orange RL-E, Die Acrylic Brilliant Blue 2B-E, Die Acrylic Turquoise Blue BG-E
(Mitsubishi Chemical Co., Ltd.) or the like which is given to the recording liquid in which the above-mentioned various physical properties are prepared can be preferably used.

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

As pigments to 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, graphite, zinc chromate, molybdenum red, Guinea green, titanium white, zinc white, and valve. Pattern, chrome oxide green, lead red, cobalt acid, barium titanate, titanium yellow, iron black, dark blue, litharge, cadmium red, silver sulfide, lead sulfate, barium sulfate, ultramarine, calcium carbonate, magnesium carbonate, lead white, Examples thereof include cobalt violet, cobalt blue, emerald green, and carbon black.

As organic pigments, most of them are classified as dyes and often overlap with dyes. Specifically, the following are preferably used.

(A) Insoluble azo (naphthol) brilliant carmine BS, lake carmine FB, brilliant fast scarred, lake red 4R, para red, permanent red R, fast red FGR, lake bordeaux 5B, vermillion NO.1, vermillion NO. .
2, Toluidine maroon.

(B) Insoluble azo (anilide) diazo yellow, fast yellow G, fast yellow 10G, diazo orange, vulcan orange, and parazolone red.

(C) Soluble azo lake orange, brilliant carmine 3B, brilliant carmine 6B, brilliant scarlet G, lake red C, lake red D, lake red R, watching red, lake bordeaux 10B, Bonmaroon L, Bonmaroon M.

(D) Phthalocyanine-based phthalocyanine blue, fast sky blue, phthalocyanine green.

(E) Dye lake system Yellow lake, Eosin lake, Rose lake, Biored lake, Blue lake, Green lake, Sepia lake.

(F) Mordant Alizarin lake, Madakamin.

(G) Vat dye-based Induslen based fast blue lake (GGS).

(H) Basic dye lake system Rhodamine lake, malachite green lake.

(I) Acid dye lake type Fossky blue, quinoline yellow lake, quinacridone type, dioxazine type.

The quantitative relationship between the liquid medium and the recording agent, other than being mixed, clogging of the liquid path, drying of the recording liquid in the liquid path, bleeding when applied to the recording member and conditions such as the drying speed, The recording agent is usually 1 to 50 parts, preferably 3 to 3 parts by weight per 100 parts of the liquid medium.
It is desirable to use 0 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 diameter of the dispersed recording agent depends on the type of the recording agent, the recording conditions, the inner diameter of the liquid path, the ejection port diameter, the recording member. If the particle size is too large, sedimentation of the recording agent particles will occur during storage, resulting in uneven concentration and clogging of the liquid path. It is not preferable because density spots occur on the recorded image or the recorded image.

In consideration of this, the particle size of the recording agent when the dispersion recording liquid is used is usually 0.01 to 30μ, preferably 0.
It is desirable that the thickness be from 01 to 20 μ, and most preferably from 0.01 to 8 μ.
Further, the particle size distribution of the dispersed recording agent is preferably as narrow as possible, usually D ± 3μ, preferably D ± 1.
Desirably, it is 5 μm (where D represents an average particle size).

Examples of the additives used include a viscosity adjuster, a surface tension adjuster, a pH adjuster, a resistivity adjuster, a wetting agent, and an infrared absorbing exothermic agent.

The viscosity adjuster and the surface tension adjuster, in addition to obtaining the above physical property values, can flow through the liquid path at a sufficient flow rate according to the recording speed, and circulate the recording liquid at the discharge port of the liquid path. It is added for the purpose of preventing the occurrence of bleeding (expansion of the spot diameter) when applied to the recording member.

As the viscosity modifier and the surface tension modifier, those which are effective without adversely affecting the liquid medium and the recording agent to be used are selected from those generally known so as to satisfy the desired properties as appropriate. Used.

Specifically, examples of suitable viscosity modifiers include polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, a water-soluble acrylic resin, polyvinyl pyrrolidone, and gum arabic.

Surface tension adjusters suitably selected and suitably used as desired include anionic, cationic and nonionic surfactants, specifically, polyethylene glycol ether sulfate as anionic, Ester salts, etc. Cationic polyoxy-2-vinylpyridine derivatives, poly-4-vinylpyridine derivatives, etc. Nonionic polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan monoalkyl Esters and polyoxyethylene alkylamines.

In addition to these surfactants, amine acids such as diethanolamine, propanolamine and morphophosphoric acid, basic substances such as ammonium hydroxide and sodium hydroxide, and substituted pyrrolidones such as N-methyl-2-pyrrolidone are also effectively used. Is done.

These surface tension modifiers do not adversely affect each other or other components, and impart to the recording liquid whose physical property values are to be prepared, such that a recording liquid having a desired value of surface tension is prepared. If necessary, two or more kinds may be used as a mixture within the specified range.

The amount of the surface tension adjuster to be added is appropriately determined according to 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 0.001 to 0.01
It is desirable to use parts by weight.

The pH adjuster is used to adjust the chemical stability of the prepared recording medium, for example, to a predetermined pH value in order to prevent changes in physical properties due to long-term storage, and to prevent sedimentation and aggregation of the recording agent and other components. Is added as appropriate within a range that does not deviate from the various characteristic values described above.

As the pH adjuster preferably used in the present invention,
As long as the desired pH value can be controlled without adversely affecting the recording liquid to be prepared, most of them can be mentioned.

Specific examples of such a pH adjuster include lower alkanolamines, for example, monovalent hydroxides such as alkali metal hydroxides, and ammonium hydroxide.

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

As the lubricant to be used, those which are more effective than those generally known in the technical field of the present invention, in particular, are thermally stable as long as the recording liquid to be prepared does not deviate from the physical properties described below. Are suitably used. Specific examples of such a lubricant include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, alkylene glycols having an alkylene group containing 2 to 6 carbon atoms such as butylene glycol and hexylene glycol; Lower alkyl ethers of diethylene glycol such as methyl ether, diethylene glycol methyl ether and diethylene glycol ethyl ether; glycerin; lower alcohol oxytriglycols such as methoxytriglycol and ethoxytriglycol; N-vinyl-2-
Pyrrolidone oligomer; and the like.

These lubricants are added in necessary amounts as required so as to satisfy the desired properties of the recording liquid, and the amount of the lubricant is usually 0.1 to 1 with respect to the total weight of the recording liquid.
It is desirably 0 wt%, preferably 0.1 to 8 wt%, and most preferably 0.2 to 7 wt%.

The above lubricants may be used alone or in combination of two or more under conditions that do not adversely affect each other.

The recording liquid used in the recording apparatus of the present invention is added with a necessary amount of the above-described additives as required. Further, when the recording liquid adheres to a recording member, the formability of the recording liquid film and the film strength are reduced. In order to obtain an excellent product, a resin polymer such as an alkyd resin, an acrylic resin, an acrylamide resin, polyvinyl alcohol, and polyvinylpyrrolidone may be added.

The recording liquid used in the recording apparatus of the present invention uses specific heat, thermal expansion coefficient, thermal conductivity, viscosity, surface tension, pH, and charged recording liquid droplets so as to have the above-described various recording characteristics. In the case of recording, it is desirable that the compounding is performed so that the characteristic value such as the specific resistance is within the condition range of the characteristic.

In other words, these properties have important relevance to the stability of the spinning phenomenon, the responsiveness and fidelity to the action of thermal energy, the image density, the chemical stability, the fluidity in the fluid path, etc. Therefore, in the present invention, it is necessary to pay sufficient attention to these when preparing the recording liquid.

It is desirable that the above-mentioned various properties of the recording liquid that can be effectively used in the recording apparatus of the present invention have the values shown in Table 6 below, but all the physical properties listed are shown in Table 6. It is not necessary to satisfy the numerical conditions as described above, and it is only necessary that some of these physical properties take values satisfying the conditions in Table 6 according to the required recording characteristics. However, the specific heat,
Regarding the coefficient of thermal expansion, the thermal conductivity, the viscosity, and the surface tension, it is desirable to specify the values in Table 6. Of course, it goes without saying that the more the properties of the prepared recording liquid satisfying the values shown in Table 6, the better the recording is performed.

Effects As is clear from the above description, the head according to the present invention has excellent heat radiation and cooling characteristics of heat generated by the heating element, and therefore has a high maximum response frequency and is suitable for high-speed printing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the vicinity of a heating element for explaining an embodiment of a liquid jet recording head according to the present invention, and FIG. 2 is a view for explaining an apparatus process of the heating element substrate shown in FIG. Figure,
FIGS. 3A and 3B are diagrams showing preferred isothermal lines due to the heating elements in the liquid jet recording head of the present invention, wherein FIG. 3A shows an isothermal line at 50 ° C., and FIG. Diagram,
FIG. 4 is a diagram showing an undesired isothermal line, and (a)
FIG. 3B is a diagram illustrating an isothermal line at 50 ° C. FIG. 3B is a diagram illustrating an isothermal line at 150 ° C. FIG. 5 is a diagram for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied, FIG. 6 is a perspective view showing an example of a bubble jet head, and FIG. FIG. 8 is a perspective view of the lid substrate viewed from the back side. 11: heating resistance layer, 12: heating element protection layer, 13: electrode protection layer, 14: second electrode (individual electrode), 15: first electrode (common electrode), 16: heat storage Layer, 17 ... insulating layer, 18 ...
Base substrate, 20 ... ink.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tomoaki Nakano 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. (56) References JP-A-60-236758 (JP, A) JP-A Sho 59-194866 (JP, A) JP-A-61-31263 (JP, A) JP-A-60-64856 (JP, A) JP-A-57-140170 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/05

Claims (1)

(57) [Claims] 1. A storage device for accommodating a recording liquid to be introduced,
A flow path provided with a thermal energy action section for generating bubbles from the recording liquid by heat and generating an action force in accordance with an increase in the volume of the bubbles; and Liquid ejection recording comprising an orifice for discharging as droplets, a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path, and means for introducing the recording liquid into the liquid chamber. In the head, including the center line of the flow path, the isothermal line on the vertical surface of the heating element substrate, when the drive pulse of the heating element is turned off, not on the orifice side with respect to the heating element, A liquid jet recording head, wherein a thermal property value and a density of a material forming the thermal energy action section are determined so as to extend to the liquid chamber side.