JPH05261925A - Ink jet recording method and recording head - Google Patents

Abstract

PURPOSE:To provide a recording method and a recording head which can form ink of different pixel-diameter out of an ink outlet as an ink jet recording means by simple and easy means to provide. CONSTITUTION:A first discharge outlet 4A of small sectional area and a second discharge outlet 4B of large sectional area are formed on a discharge outlet T, and ink meniscus is formed on the proper positions of discharge outlets 4A-4B by the action of a second energy working section 9B for changing the position of meniscus, and ink drops corresponding to the position of meniscus can be jetted by the action of a first energy working section 9A for jetting ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method and a recording head, and more particularly to an ink jet recording method and a recording head capable of changing a pixel diameter in an ink jet printer.

[0002]

2. Description of the Related Art The non-impact recording method has recently been drawing attention because noise during recording is extremely small to a negligible level. Among the recording methods, high-speed recording is possible, and the so-called inkjet recording means that can record on plain paper without requiring a special fixing process is an extremely powerful recording method. Various methods have been proposed so far, some of which have been improved and commercialized, and some of which are still being put into practical use.

In such an ink jet recording method, small droplets of a recording liquid, so-called ink, are ejected and adhered to a recording member (recording paper) for recording, and this recording liquid is used. The method is roughly classified into several methods according to the method of generating droplets and the control method of controlling the flight direction of the generated droplets of the recording liquid.

First, as a first method, for example, USP3
The method disclosed in the specification of No. 060429 (Tele)
There is a type method). In this method, the droplets of the recording liquid are generated electrostatically, the generated droplets of the recording liquid are subjected to electric field control according to the recording signal, and are selectively adhered to the recording member for recording. is there. More specifically, by applying an electric field between the nozzle and the accelerating electrode, uniformly charged droplets of the recording liquid are ejected from the nozzle, and the ejected droplets of the recording liquid are responded to the recording signal. Recording is performed by flying between xy deflection electrodes configured to be electrically controllable, and selectively depositing a small droplet of the recording liquid on the recording member according to a change in the electric field strength.

The second method is, for example, USP359627.
5 and US Pat. No. 3,298,030, etc., is a method (Sweet method), which generates small droplets of a recording liquid whose charge amount is controlled by a continuous vibration generation method, and Recording is performed on the recording member by causing a controlled droplet of the recording liquid to fly between the deflection electrodes to which a uniform electric field is applied.

Specifically, before the orifice (ejection port) in the recording head provided with the piezoelectric vibrating element,
Charging electrodes configured to apply a recording signal are arranged apart from each other by a predetermined distance, an electric signal having a constant frequency is applied to the piezoelectric vibrating element to mechanically vibrate the piezoelectric vibrating element, and the piezoelectric element is ejected from the ejection port. Eject small droplets of recording liquid. At this time, electric charges are electrostatically induced in the small droplets of the recording liquid ejected by the charging electrodes, and the small droplets of the recording liquid are charged with an amount of electric charge according to the recording signal. When the droplets of the recording liquid of which the charge amount is controlled fly between the deflection electrodes to which a constant electric field is uniformly applied, the droplets are deflected according to the added charge amount and carry the recording signal. Only the small droplets can adhere to the recording member.

The third method is, for example, USP341516.
According to the method disclosed in Japanese Patent No. 3 (Hertz method), an electric field is applied between a nozzle and a ring-shaped charging electrode, and small droplets of a recording liquid are generated and atomized by a continuous vibration generation method for recording. It is a method. That is, in this method, the atomization state of the small droplets of the recording liquid is controlled by modulating the electric field strength applied between the nozzle and the charging electrode according to the recording signal, and recording is performed with gradation of the recorded image. Is.

A fourth method is, for example, USP374712.
Method disclosed in specification No. 0 (Stemme method)
The principle of this method is fundamentally different from the above three methods. That is, in all of the three methods, the droplets of the recording liquid ejected from the nozzles are electrically controlled during the flight, and the droplets of the recording liquid that carry the recording signal are selectively recorded. On the other hand, the recording is performed by adhering the recording liquid onto the upper surface, whereas in this method, a small droplet of the recording liquid is ejected and ejected from an ejection port according to a recording signal to perform recording.

That is, according to this method, an electric recording signal is applied to a piezo vibrating element attached to a recording head having an ejection port for ejecting a small droplet of recording liquid, and this electric recording signal is piezo-vibrated. Recording is performed by changing to mechanical vibration of the element, and ejecting small droplets of the recording liquid from the ejection port according to the mechanical vibration and ejecting the droplets onto the recording member.

These four conventional methods have their respective characteristics, but on the other hand, they also have a point to be solved. That is, in the first to third methods, the direct energy for generating the recording liquid droplets is electrical energy, and the deflection control of the recording liquid droplets is also electric field control. Therefore, the first method is simple in configuration, but requires a high voltage to generate small droplets of the recording liquid, and it is difficult to form the recording head with multiple nozzles. Therefore, the first method is not suitable for high-speed recording. is there.

The second method is suitable for high-speed recording because the recording head can have multiple nozzles, but has a complicated structure, and it is difficult and difficult to electrically control small droplets of the recording liquid. There is a problem that satellite dots are easily formed on the member. The third method has a feature that an image excellent in gradation can be recorded by atomizing the small droplets of the recording liquid, but on the other hand, it is difficult to control the atomized state, and fog is generated in the recorded image. However, there are various problems that it is difficult to make the recording head multi-nozzle and it is not suitable for high-speed recording.

The fourth method has many advantages over the first to third methods. That is, since the configuration is simple and the recording liquid is ejected from the ejection ports of the nozzles on-demand to perform recording, it is suitable for ejecting and ejecting as in the first to third methods. Of these, it is not necessary to collect the small droplets that were not required for image recording, and there is no need to use a conductive recording liquid as in the first and second methods, and it is a substance of the recording liquid. It has great advantages such as a high degree of freedom.

On the other hand, on the other hand, it is difficult to form a multi-nozzle print head because of problems in processing the print head, miniaturization of a piezoelectric vibrating element having a desired resonance number, and the like. In addition, since a small amount of recording liquid is ejected and ejected by mechanical energy such as mechanical vibration of the piezoelectric vibrating element, it is not suitable for high-speed recording.

As described above, in the conventional liquid jet recording method,
In terms of configuration, there are advantages and disadvantages in terms of high-speed recording, multi-nozzle recording head, generation of satellite dots, fog of recorded images, and the like, and there is a constraint that it can be applied only to applications that take advantage of the advantages.

However, such an inconvenience can be substantially eliminated by adopting the ink jet recording method as the liquid jet recording method previously proposed by the present applicant. As one of such ink jet recording systems, there is Japanese Patent Publication No. 56-9429. In this method, the ink in the liquid chamber is heated to generate bubbles to cause a pressure increase in the ink, the ink is ejected from a fine capillary nozzle, and recording is performed on a recording member. After that, many inventions were made to improve this principle.

One of the improved inventions is, for example, Japanese Patent Publication No. 59-31943. This is to change the recording pixel diameter by applying a signal having gradation information to an electrothermal converter having a heat generating portion having a heat generation amount adjusting structure and generating heat in the heat generating portion according to the signal. It is a feature. Specifically, the structure is such that the thickness of the protective layer, the heat storage layer, or the heating element layer gradually changes, or the pattern width of the heating element layer gradually changes.

In order to obtain the constitution of the portion of the electrothermal converter, it is necessary to form a three-dimensional structure by the thin film forming technique, and it is practically impossible to obtain the constitution. However, it has the disadvantage of being extremely expensive. Further, in the case where the pattern width of the heat generating portion is changed, there is a problem that disconnection is apt to occur at the narrowest pattern, and good results cannot be obtained in terms of durability.

On the other hand, Japanese Patent Laid-Open No. 63-42872 discloses a similar gradation recording technique. This is also the special public Sho 59
Similar to the technique of Japanese Patent Publication No. 31943, it is characterized in that it has a three-dimensional structure of the heating element layer, and has a drawback that it is extremely difficult to manufacture. Furthermore, JP-A-63-
Japanese Patent No. 42869 discloses a technique of controlling the discharge amount by changing the number of times bubbles are generated by changing the time for which the resistor is energized. However, in a normal bubble jet, the energization time is limited to several to ten and several μs, and if the energization is continued for a longer time, the heating element is broken, so this technology is practically unfeasible in terms of durability. Is.

[0019]

As described above, in the prior art, various attempts have been made to change the pixel diameter, but from the viewpoint of manufacturing, durability, or high density. Satisfactory results have not been obtained in terms of arrangement. The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an inkjet recording method and a recording head capable of easily changing a pixel diameter, which has a simple configuration and is easy to manufacture. It is what

[0020]

In order to achieve the above object, the present invention provides, as an ink jet recording method, a plurality of energy acting portions for one ejection port, and the ejection port has a large cross-sectional area. And the position of the ink meniscus formed at the ejection port of which the cross-sectional area is changed is changed by the operation of at least one energy application unit of the plurality of energy application units. Alternatively, it is characterized in that ink droplets having different diameters can be ejected.

Further, as an ink jet recording method of the present invention, a single energy acting portion is provided for one discharge port, and the size of the cross sectional area of the discharge port is changed, and the cross sectional area is changed. The position of the ink meniscus formed at the ejection port can be changed by changing the water head difference between the ink supply unit and the ejection port, and ink droplets having different masses or diameters can be ejected from a single ejection port. It is a thing.

According to the present invention, as an ink jet recording head, an ink supply unit, a liquid chamber for guiding the ink from the ink supply unit, a flow channel for guiding the ink from the liquid chamber to each ejection port, and along each flow channel A single energy acting portion or a plurality of energy acting portions which are independently arranged and can be driven independently, an ejection port provided at each flow path end for ejecting ink having a changed cross-sectional area, and the ejection port And means for changing the position of the ink meniscus formed on the.

The present invention is characterized in that, in the ink jet recording head, the cross-sectional area of the ejection port whose cross-sectional area is changed is changed from a small cross-sectional area toward a flow path end side. It is a thing.

Further, according to the present invention, in order to change the generation position of the ink meniscus at the ejection port having the changed cross-sectional area, the inkjet recording head provided with a single energy acting portion has a function with respect to the height of the ejection port. An ink jet recording head provided with a means for changing the height of the ink supply means, and in an inkjet recording head having a plurality of energy acting portions, at least one energy acting portion of the plurality of energy acting portions. Operates for switching the position of the ink meniscus.

[0025]

According to the constitution of the present invention, in the ink jet recording head having a single energy acting portion, the height of the ink supply means is changed with respect to the height of the ejection port to change the size of the cross-sectional area. An ink meniscus can be formed at an appropriate position of the ejection port, and the pixel diameter can be easily changed with a single ejection port. Further, in an ink jet recording head having a plurality of energy acting portions, at least one of the energy acting portions is operated for switching the position of the ink meniscus, and the ink is ejected at a proper position in the ejection port with the cross-sectional area changed. The pixel diameter can be easily changed by forming a meniscus and using a single ejection port.

[0026]

First, the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied will be described with reference to FIG. 2 is a perspective view of the bubble jet head shown in FIG. 1, and FIG. 3 is a perspective view of the head of FIG. 2 disassembled into a lid substrate (FIG. 3A) and a heating element substrate (FIG. 3B). FIG. 4 is a perspective view of the lid substrate shown in FIG. 3A as viewed from the back side. In the figure, 1 is a lid substrate, 2 is a heating element substrate, 3 is a recording liquid inflow port, 4 is a discharge port, 5 is a flow path, 6 is a region for forming a liquid chamber, 7 is an individual (independent) electrode, 8
Is a common electrode, 9 is a heating element (heater), 10 is ink, 1
Reference numeral 1 is a bubble, and 12 is a flying ink liquid.

Then, referring to FIG. 1, the ink ejection by the bubble jet will be described. (A) is a steady state, in which the surface tension of the ink 10 and the external pressure at the ejection port 4 are in equilibrium. (B) shows a state in which the heating element 9 as a heater is heated, the surface temperature of the heating element 9 rises sharply, and is heated until the boiling phenomenon occurs in the adjacent ink layer, and the minute bubbles 11 are scattered.

(C) shows a state in which the adjacent ink layer rapidly heated on the entire surface of the heating element 9 is instantly vaporized to form a boiling film, and the bubble 11 grows. At this time, the pressure in the nozzle rises as much as the bubbles grow, the balance with the external pressure on the ejection port surface is lost, and the ink column starts to grow from the ejection port 4. In (d), the bubble 11 has grown to the maximum, and the ink 10 corresponding to the volume of the bubble is pushed out from the ejection port surface. At this time, no current is flowing through the heating element 9, and the surface temperature of the heating element 9 is decreasing. The maximum value of the volume of the bubble 11 is slightly delayed from the timing of applying the electric pulse.

(E) shows a state in which the bubble 11 is cooled by ink or the like and starts to contract. At the front end of the ink column, the ink column moves forward while maintaining the pushing speed, and at the rear end of the ink column, the internal pressure of the nozzle decreases due to the contraction of the bubble 11, and the ink flows backward from the ejection port surface into the nozzle, thus constricting the ink column. Is occurring.

In the state (f), the bubble 11 is further contracted, the ink contacts the surface of the heating element, and the surface of the heating element is further rapidly cooled. On the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so a large meniscus has entered the nozzle. The tip of the ink column becomes a droplet and flies toward the recording paper at a speed of 5 to 10 m / sec.
(G) is a process in which the ink is supplied to the ejection port again by the capillary phenomenon and returns to the state of (a), and the bubbles are completely extinguished.

FIG. 5 shows an embodiment for explaining the construction of the main part of the liquid jet recording head described above. FIG. 5A is a detailed front partial view seen from the ejection port side of the bubble jet head.
(B) is a partial cross-sectional view taken along the alternate long and short dash line xx in (a). Recording head 13 shown in this drawing
The structure is formed by arranging and bonding a grooved plate 16 having a predetermined number of grooves of a predetermined linear density and a predetermined width and depth on a substrate 15 having the electrothermal converter 14 provided on the back surface. A liquid ejection portion 18 including an ejection port 17 for ejecting the liquid is formed at the end of the recording head.

The liquid discharge part 18 is a place where thermal energy generated from the discharge port 17 and the electrothermal converter 14 acts on the liquid to generate bubbles, which causes a rapid state change due to expansion and contraction of the volume. And a certain heat acting part 19. The heat acting portion 19 is the heat generating portion 20 of the electrothermal converter 14.
The bottom surface of the heat generation surface 20 is a heat acting surface 21, which is a surface of the heat generating portion 20 in contact with the liquid. Heat generation part 20
Is a lower layer 22 provided on the substrate 15 and the lower layer 22.
The heating resistor layer 23 is provided on the heating resistor layer 23, and the protective layer 24 is an upper layer provided on the heating resistor layer 23.

The heating resistance layer 23 is provided with electrodes 25, 26 on its surface for energizing the heating layer 23 in order to generate heat. 20 are formed. The electrode 25 is an electrode common to the heat generating portion 20 of each liquid ejecting portion 18, and the electrode 26 is a selection electrode for selecting the heat generating portion 20 of each liquid ejecting portion 18 to generate heat. It is provided along the liquid flow path of the discharge part 18.

The protective layer 24 fills the heat generation resistance layer 23 and the liquid flow path of the liquid discharge part 18 in order to chemically and physically protect the heat generation resistance layer 23 in the heat generation part 20 from the liquid used. It has a role of separating the existing liquid, preventing a short circuit between the electrodes 25 and 26 through the liquid, and further preventing an electric leak between the adjacent electrodes. The liquid flow path provided in each liquid discharger 18 constitutes a part of the liquid flow path upstream of each liquid discharger, and
They communicate with each other via a common liquid chamber (not shown). The electrodes 25 and 26 connected to the electrothermal converters 14 provided in the respective liquid discharge parts are protected by the protective layer 24 which is the upper layer and are provided on the upstream side of the heat acting part due to the design. , So as to pass under the common liquid chamber.

FIG. 6 is a detailed view for explaining the structure of the bubble generating portion using a heating resistor, in which 27 is a heating resistor, 28 is an electrode, 29 is a protective layer, and 30 is a power supply device. Shows. A useful material for the heating resistor 27 is, for example, a tantalum-SiO ₂ mixture,
Examples thereof include tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor, and borides of metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium and vanadium.

Among the materials composing these heating resistors 27, metal borides can be cited as particularly excellent ones. Among them, hafnium boride has the most excellent characteristics, and then, The order is zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride. The heating resistor 27 can be formed by using a method such as electron beam vapor deposition or sputtering using the above materials. The film thickness of the heating resistor 27 is determined according to the area, the material, the shape and size of the heat acting portion, and the actual power consumption so that the amount of heat generated per unit time becomes a desired value. In general, it is 0.001 to 5 μm, preferably 0.01 to 1 μm.
It is said that.

As the material forming the electrode 28, many of the commonly used electrode materials can be effectively used.
Specifically, for example, Al, Ag, Au, Pt, Cu, and the like are used, and these are provided in a predetermined position, with a predetermined size, shape, and thickness by means such as vapor deposition.

The characteristic required for the protective layer 29 is that it does not prevent the heat generated by the heating resistor 27 from being effectively transferred to the recording liquid, and protects the heating resistor 27 from the recording liquid. is there. Examples of useful materials for forming the protective layer 29 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide and the like. These can be formed using a technique such as electron beam evaporation or sputtering. The thickness of the protective layer 29 is usually 0.01 to
10 μm, preferably 0.1-5 μm, optimally 0.1
It is desirable that the thickness is formed to be about 3 μm.

Based on the above principle, in the bubble jet technology provided with a heating element structure, the present invention provides an ink ejection region T and a flow path 5 near the ink ejection region as shown in the conceptual diagram of FIG. It is characterized by the configuration of the heating element S provided. That is, the shape of the ink ejection region T is composed of the ejection port 4A having a small cross-sectional area and the ejection port 4B having a large cross-sectional area opened to the outside from the ejection port 4A. A first heating element (ejection heating element) 9A and a second heating element (ink meniscus forming heating element) 9B, which can be independently controlled, are arranged along the flow path 5. Although not shown,
As is well known, a liquid chamber and an ink supply means for introducing ink into the liquid chamber are connected to the flow path 5, and the ink jet head is formed together with the flow path portion including the ink ejection region T and the heating element S. I am configuring.

The mass of the ejected ink droplet depends on the dimensions of the ink ejection port (the cross-sectional area and the length of the ejection port). Therefore, in order to change the mass of the ejected ink droplet, the diameter of the ink ejection port may be changed. In the present invention, in order to change the mass of the discharged ink droplet, the generation position of the ink meniscus at the time of discharging is set near the first discharge port 4A having a small cross-sectional area or the second discharge port 4B having a large cross-sectional area. The mass of the ejected ink droplet is changed depending on whether or not it is close to. The means for changing the generation position of the ink meniscus will be described later.

In FIG. 9A, when the position of the ink meniscus is generated in the vicinity of the first ejection port 4A having a small sectional area, the position of the ink meniscus is shown in FIG. 9B.
The case where it is generated in the vicinity of the second ejection port 4B having a large cross-sectional area is shown, and in each case, the ejected ink droplet 1
The difference in mass (size) between 2A and 12B is shown. The position of the ink meniscus can be formed in the first ejection port 4A and the second ejection port 4B due to the action of the second heating element 9B, and the ink formed at the predetermined position of the ejection port can be formed. The principle of ejection is the same as that described in FIG.
The operation is the same as the operation based on the ink ejection of the bubble jet by the action of the first heating element 9A.

Next, a method of manufacturing the bubble jet head applied to the present invention will be described according to the manufacturing steps shown in FIGS. The examples shown here relate to a discharge port, a flow path, and a common liquid chamber made of a cured film of a photosensitive resin. In the figure, 31 is a substrate, 32 is an ink ejection pressure generating element,
33 is a thin film, 34 is an adhesive layer, 35 is a dry film photoresist, 36 is a photomask, 37 adhesive, 38
Is a flat plate and 39 is a groove.

In the process shown in FIG. 4, a desired number of ink ejection pressure generating elements 32 such as heating elements and piezo elements are arranged on a substrate 31 made of silicon, glass, ceramic, plastic, metal or the like, and further, if necessary. For the purpose of imparting ink resistance and electrical insulation, a thin film 33 of SiO ₂ , Ta ₂ O ₅ , glass or the like is coated. The ink ejection pressure generating element 3
Although not shown, 2 is connected to a signal input electrode.

In the step shown in FIG. 5, the adhesive layer 34 is formed on the surface of the substrate 31 having the ink ejection pressure generating element 32 in a thickness of about 1 μm to 5 μm. At this time, a desired liquid adhesive is formed by a known method, for example, a spinner coating method,
After coating the surface of the substrate by the dip coating method or the roller coating method, it is semi-cured. In addition, specifically,
In the case of the spinner coating method, an adhesive having a viscosity of 2 to 15 cp is applied at 1000 to 5000 rpm. In the case of the dip coating method, the substrate 1 is dipped in an adhesive having a viscosity of 20 to 30 cp and then lifted at a constant speed of 20 to 50 cm / min. Further, in the case of the roller coating method, the viscosity is 10
Adhesive of 0-300cp, speed between rollers 60-200c
Apply at m / min.

The kind of the adhesive used here is not particularly limited as long as it exhibits a predetermined adhesive force, but in the present invention, a photo-curable resin adhesive is especially recommended for the convenience of production. It is a thing. Thus, in the present invention,
Suitable photocurable resin adhesives include, for example, unsaturated polyester resins and monomers, dimers or oligomer compounds having at least one unsaturated double bond in the molecule (methyl methacrylate, styrene, diallyl phthalate, etc.) 1 Or unsaturated polyester and at least 1
It is composed of a single resin such as silicon, urethane or epoxy modified so as to have one unsaturated double bond in the end chain group or main chain, or a combination of the same with the above-mentioned monomers, dimers, oligomers and the like. Further, in the present invention, when the adherend interface of these adhesives is formed of a compound based on Si, a silane coupling agent is mixed with the above-mentioned adhesive, or the surface of the substrate 31 is preliminarily coated with silane. Treatment with a coupling agent is also effective.

In the subsequent step shown in FIG. 6, the surface of the adhesive layer 34 of the substrate 31 obtained through the step shown in FIG.
The dry film photoresist 35 (film thickness, about 25 μ to 100 μ) heated to about 100 ° C. to about 100 ° C.
Laminate under a pressure condition of 0.4 kg / cm ² at a speed of 0.4 f / min. At this time, the dry film photoresist 35 is fused to the adhesive layer 34.

Thereafter, the adhesive layer 34 is irradiated with ultraviolet rays in accordance with the properties of the used adhesive agent to be fully cured. After that, even when a considerable external pressure is applied to the dry film photoresist 35, the dry film photoresist 35 is not separated from the substrate 31.
Subsequently, as shown in FIG. 6, a photomask 36 having a predetermined pattern is superposed on the dry film photoresist 35 provided on the substrate surface, and then the photomask 3 is formed.
Exposure is performed from the upper part of 6.

At this time, it is necessary to align the position of the ink discharge pressure generating element 32 with the above-mentioned pattern by a known means. And in the head of the present invention,
As shown in FIGS. 1 to 3, the ink ejection area T, which is the tip of the ejection port, has a constant sectional area from the first ejection port 4A having a small cross-sectional area to the second ejection port 4B having a large cross-sectional area. Since the pattern does not exist, a shape that matches the shape of the ink ejection area is used.

FIG. 7 is an explanatory view showing a state after the step of dissolving and removing the unexposed portion of the exposed dry film photoresist 35 with a developing solution containing a predetermined organic solvent. Next, in order to improve the ink resistance of the exposed portion 35P of the dry film photoresist 35 left on the substrate 31, a heat curing treatment (for example, 3 at 150 to 250 ° C.) is performed.
0 minutes to 6 hours heating), or ultraviolet irradiation (for example, 50 to
200 mw / tm ² or more (ultraviolet intensity) to sufficiently enhance the polymerization and curing reaction. It is also effective to use both the above-mentioned thermal curing and ultraviolet curing.

By the way, the adhesive layer 34 used is the groove 39.
If it remains in the ink, it may be dissolved in the ink to change the quality of the ink, the ink passage may be clogged, or the function of the ink ejection pressure generating element 32 may be impaired. At the time of pattern exposure of the photoresist 35 (FIG. 6), the adhesive layer 34 is also photocured at the same time, and the uncured adhesive layer 34 is dissolved and removed together with the dry film photoresist 35 in the subsequent developing step with an organic solvent (FIG. 7). ).

FIG. 8 shows the result of the dry film photoresist 35P cured after sufficient polymerization as described above.
It is a drawing showing a state in which a flat plate 38 is bonded or simply press-bonded and fixed in order to form a ceiling on the substrate 31 in which the groove 39 serving as an ink passage is formed. A specific method for constructing the ceiling in the step shown in FIG. 8 will be described below.
1) A flat plate 38 made of glass, ceramic, metal, plastic, or the like was spinner-coated with an epoxy adhesive to a thickness of 3 to 4 μm, and then preheated to make the adhesive 37 a so-called B stage and hardened. The adhesive is main-cured by adhering it onto the dry film photoresist 35P. Alternatively, 2) a method in which a flat plate 38 made of a thermoplastic resin such as an acrylic resin, an ABS resin, or polyethylene is directly heat-sealed on the cured dry film photoresist 35P can be used.

Next, the means for changing the generation position of the ink meniscus in the ink ejection areas having different sectional shapes according to the present invention will be described. As a means therefor, a method of controlling the back pressure related to the head, a method of generating and controlling bubbles by a heater, or the like can be applied.

First, a method for controlling the back pressure of the head will be described. FIG. 9 is a concrete example of the embodiment, and shows the relationship between the orifice portion of the recording head and the ink supply means. Between the ink supply means 53 and the flow passage 45 in the head H, the portion of the orifice 44 for ejecting ink, the static pressure due to the head difference of the height h, the fluid resistance in the flow passage 45 and the orifice 44, and the orifice 44. The surface tension of the ink balances with the ink meniscus holding force so that the ink does not flow out from the orifice 44.

In the embodiment of FIG. 9 as well, although not clearly shown in the drawing, the shape of the orifice 44 for ejecting ink is similar to that shown in FIG. The position where the ink meniscus is formed can be changed depending on the head difference. In this drawing, 41 is a lid substrate, 42 is a heating element substrate, 43 is a recording liquid inlet, 46 is a region for forming a liquid chamber, and 49 is a heating element.

In the present invention, as shown by the arrow A in the figure, the height of the ink supply means 53 can be adjusted to be variable. In this way, the ink container 5 as the ink supply means is provided to the side of the flow path 45 and the orifice 44.
By making the height of 3 variable, the position of the ink meniscus in the orifice portion 44 of the recording head H of the present invention can be easily changed.

In the embodiment of FIG. 9, the ink supply means 53 is arranged at a position higher than the orifice portion side of the recording head, but the position of the ink supply means 53 is lower than the orifice portion of the recording head H. By setting the position, the ink meniscus at the orifice 44 can be retracted to the side of the liquid chamber 46 having a small cross-sectional area.
Further, as described above, as a mechanism for changing the height of the ink supply means 53, a solenoid is connected to a member for mounting and holding the ink supply means, and the solenoid is controlled up and down by an electric means to control the ink supply means. It is possible to change the height of.

Next, as another embodiment of the present invention, two heating elements 9A and 9B are used as a plurality of energy acting portions, and these two heating elements 9A and 9B are provided in the vicinity of the discharge port 4. The discharge ports 4 are arranged along the flow path 5, and each of the discharge ports 4 is composed of a discharge port 4A having a small cross-sectional area and a discharge port 4B having a large cross-sectional area. The two heating elements 9A and 9B are controlled and discharged. Change the position of the ink meniscus at the outlet 4,
In addition, a case will be described in which bubbles are generated in the ink located in the flow path to change the size of the ink droplet that is ejected from the ejection port. In order to explain this example, changes in ink at the ejection port and the heating element portion are shown in FIGS. Each of FIGS. 10 to 17 includes a top view (a) and a side sectional view (b).

FIG. 10 shows a steady state in which the surface tension of the ink 10 and the external pressure are in equilibrium at the ejection port 4 composed of 4A and 4B. In this case, the ink meniscus is located at the ejection port 4B having a small cross-sectional area. In FIG. 11, the second heating element 9 </ b> B, which is one of the energy acting portions arranged in the flow path 5 separated from the discharge port 4, is heated. In this case, the second heating element 9B moves the position of the ink meniscus located in FIG. 10 from the position of the first ejection port 4A having a small sectional area to the second ejection port 4B having a large sectional area. Therefore, low energy is applied to such an extent that the ink does not eject from the ejection port 4, the bubble 11A is generated by the low energy, and the pressure of the bubble 11A causes the ink meniscus to have the second ejection port having a large cross-sectional area. It is extruded to the vicinity of 4B.

After that, as shown in FIG. 12, the first heating element 9A is heated, the surface temperature of the first heating element 9A rises sharply, and is heated until the boiling phenomenon occurs in the adjacent ink layer, and the minute The state where the air bubbles 11B are scattered is shown. Further, subsequently, as shown in FIG. 13, a state in which the adjacent ink layer rapidly heated on the entire surface of the first heating element 9A is instantly vaporized to form a boiling film, and the bubble 11B grows. At this time, the pressure in the nozzle rises as much as the bubbles grow,
The balance with the external pressure on the ejection port surface is lost, and the ink column starts to grow from the ejection port 4B.

FIG. 14 shows a state in which the bubble 11B has grown to the maximum, and the ink 10 corresponding to the volume of the bubble is pushed out from the ejection port surface. At this time, no current is flowing through the first heating element 9A, and the surface temperature of the first heating element 9A is decreasing. The maximum value of the volume of the bubble 11B is slightly delayed from the timing of applying the electric pulse.

FIG. 15 shows a state in which the bubble 11B is cooled by ink or the like and starts to contract. At the front end of the ink column, the ink column moves forward while maintaining the pushed speed, and at the rear end, the internal pressure of the nozzle decreases as the bubble 11B contracts,
The ink flows backward from the ejection port surface into the nozzle, and the ink column is constricted.

FIG. 16 shows a state in which the bubble 11B is further contracted, the ink contacts the surfaces of the two heating elements 9A and 9B, and the heating element surfaces are cooled more rapidly. On the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so that a large meniscus enters the nozzle. Droplets 12 form at the tip of the ink column and fly toward the recording paper at a speed of 5 to 10 m / sec. FIG. 17 shows a process in which the ink is supplied to the ejection port 4 again by the capillary phenomenon and returns to the state of FIG. 10, and the bubbles have completely disappeared. The bubble 11A disappears at the same time as or before the bubble 11B.

In the present invention, an electrostrictive vibrator (piezo element) can be used instead of using a heating element as an energy acting portion, and an on-demand type ink jet system using the electrostrictive vibrator can be used. Can also be applied. FIG. 18 shows an electrostrictive vibrator (piezo element) as an energy acting unit.
56 is used, and a pulsed signal voltage is applied to this electrostrictive vibrator (piezo element) 56 to generate an electrostrictive vibrator (piezo element).
Is distorted, the volume of the ink pressure chamber 57 is reduced, a pressure wave is generated, and the ink droplet 59 is ejected from the orifice 58. Reference numeral 60 is an ink supply port. Of course, it is a matter of course that a plurality of ink pressure chambers and electrostrictive vibrators (piezo elements) are arranged to form a multi-orifice head, and the present invention can be applied to this structure.

In the present invention, when the energy acting portion is used as the means for changing the position of the ink meniscus, two energy acting portions have been described as an example, but the invention is not limited to this. Instead, it shows that it is possible by combining a plurality of action parts.

Next, a specific example of the present invention will be described. Specific Example 1 In the inkjet head having the shape shown in FIG. 1, the first ejection port 4A having a small cross-sectional area to the second ejection port having a large cross-sectional area.
In the ink ejection area including the ejection ports 4B, the length a of the first ejection port 4A is 32 μm, the length b of the second ejection port 4B is 50 μm, and the size of the first heater 9A is 30 μm.
× 100 μm, and its resistance value was 120Ω.

In the ink jet head having such conditions, the position of the ink meniscus is at the portion of the first ejection port 4A having a small sectional area, and in this state,
Only the first heater 9A was driven under the conditions of a driving voltage of 25 V, a pulse width of 6 μs, and a continuous driving frequency of 4 kHz. Under this condition, the average diameter of recorded pixels is φ
It was 95 μm (average value of n = 10).

In Specific Example 1, in addition to the first heater 9A, the size is 30 μm × 10, as described above.
A second heater 9B having a resistance value of 120Ω was provided as shown in FIG. Then, in a state where the position of the ink meniscus is in the portion of the first ejection port 4A having a small cross-sectional area, first, the second heater 9B is
It was driven under the following conditions. Drive voltage: 20 V, pulse width: 5 μs, continuous drive frequency: 4 kHz

Then, after driving the second heater 9B, 3
After 0 μsec had elapsed, the first heater 9A was driven under the following conditions. Drive voltage: 25 V, pulse width: 6 μs, continuous drive frequency: 4 kHz As described above, the second heater 9B and the first heater 9A
The average diameter of the pixels discharged from the discharge port by driving
It was φ140 μm (average value of n = 10). It was also observed that the position of the ink meniscus in this example moved from the portion of the first ejection port 4A having a small sectional area to the portion of the second ejection port 4B having a large sectional area.

Concrete Example 2 A first heater 9A and a second heater 9B similar to those in Concrete Example 1 are used, and the second heater 9B is driven under the conditions shown in Table 1 below, and the second heater 9B is used. After driving
When the first heater 9A was driven under the same driving conditions as in Example 1 after the time shown in (1) had elapsed, pixels having pixel diameters as shown in Table 1 were obtained.

[Table 1]

Specific Example 3 This is related to the example of FIG. 9, and in the specific example shown in FIG. 19, an ink ejection region composed of the first ejection port 4A having a small cross-sectional area to the second ejection port 4B having a large cross-sectional area. Is
The length a of the first discharge port 4A is 32 μm, and the length of the second discharge port 4 is 32 μm.
The length b of B was 50 μm, the length L of the ink ejection region was 50 μm, and the distance T between the end of the ejection port and the heater 49 was 160 μm. The size of the heater 49 is 30 μm × 100 μm, and its resistance value is 120Ω.
And The heater 49 has a continuous driving frequency:
4 kHz was applied.

In this specific example 3, the distance from the center of the ejection port 44 to the ink surface of the ink supply tank 53 is h,
The upward movement of the supply tank 53 from the position shown in the figure by the distance h is represented by a positive value, and the downward movement is represented by a negative value, and the pixel diameter based on the movement amount is changed as shown in Table 2.

[Table 2]

Practical Example 4 In this example, a piezo element is used as the energy acting portion. As shown in FIG. 20, as the ink ejection region, the length a of the first ejection port 4A having a small cross-sectional area is 42 μm and the second ejection port 4B having a large cross-sectional area is provided at the end of the flow path. The length b of the portion was set to 60 μm. And
1.5m in the flow path near the first discharge port 4A
A first piezo element 56A of m (y) × 4 mm (x) is arranged.

Then, only the first piezo element 56A was driven under the following driving conditions with respect to the ink in which the position of the ink meniscus was at the portion of the first ejection port 4A having a small cross-sectional area. Driving voltage: 45 V, pulse width: 6 μs, maximum driving frequency: 3.2 kHz As a result of driving the first piezo element 56A under these conditions, the average diameter of recorded pixels is φ135 μm (n =
(Average value of 10).

In Example 4, the second piezo element 56B, in addition to the first piezo element 56A, is arranged in the energy acting portion along the flow path 5 on the side opposite to the ejection region. The size of the second piezo element 56B is 1.5.
It is mm (y) x 2 mm (x). Therefore, for the ink in which the position of the ink meniscus is in the portion of the first ejection port 4A having a small cross-sectional area, first, the second piezo element 56B
Was driven at a driving voltage of 30 V, a pulse width of 5 μs, and a maximum driving frequency of 3.2 kHz.

Then, after 40 μsec has elapsed since the second piezo element 56B was driven, the first piezo element 56A is driven with a driving voltage of 26.5 V and a pulse width of 6 μs.
Maximum driving frequency: It was driven at 3.2 kHz. As a result, the average diameter of recorded pixels is 162 μm (n = 1).
The average value was 0). In addition, the second piezo element 56B
It was observed that the position of the ink meniscus moved from the portion of the first ejection port 4A having a small cross-sectional area to the portion of the second ejection port 4B having a large cross-sectional area by the action of.

[0076]

According to the structure of the present invention, in various inkjet recording means such as an inkjet printer, the cross-sectional shape of the ink ejection region is changed so that the position of the ink meniscus is changed by the action of the energy acting portion or from the center of the ejection port. It can be changed by changing the height of the supply tank, and has an effect that ink droplets having different masses and diameters can be ejected from one ejection port.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a configuration of an ink ejection area and a heating element portion in an inkjet recording unit of the present invention.

FIG. 2 shows the relationship between the position of an ink meniscus and flying ink drops in the inkjet recording means of the present invention,
(A) is a plan view and (b) is a side view.

3A and 3B show the relationship between the position of another ink meniscus and flying ink droplets in the inkjet recording means of the present invention, FIG. 3A is a plan view, and FIG. 3B is a side view.

FIG. 4 is an explanatory diagram showing a first stage of a method of manufacturing a bubble jet head applied to the present invention.

FIG. 5 is an explanatory view showing a second stage of the method of manufacturing the bubble jet head applied to the present invention.

FIG. 6 is an explanatory diagram showing a third stage of the method of manufacturing a bubble jet head applied to the present invention.

FIG. 7 is an explanatory view showing a fourth stage of the method of manufacturing the bubble jet head applied to the present invention.

FIG. 8 is an explanatory view showing the final stage of the method of manufacturing a bubble jet head applied to the present invention.

FIG. 9 is a schematic cross-sectional view for explaining one embodiment of the present invention, showing a means for controlling the back pressure related to the recording head and changing the position of the ink meniscus at the ejection port of which the cross-sectional area is changed.

FIG. 10 is an explanatory view for using the two thermal energy acting portions of the present invention to change the position of the ink meniscus and fly the ink droplet.

FIG. 11 is an explanatory diagram for using the two thermal energy acting portions of the present invention to change the position of the ink meniscus and cause the ink droplets to fly.

FIG. 12 is an explanatory view for using the two thermal energy acting portions of the present invention to change the position of the ink meniscus and fly the ink droplets.

FIG. 13 is an explanatory diagram for using the two thermal energy acting portions of the present invention to change the position of the ink meniscus and cause ink droplets to fly.

FIG. 14 is an explanatory diagram for changing the position of the ink meniscus to cause the ink droplets to fly by using the two thermal energy acting units of the present invention.

FIG. 15 is an explanatory diagram for changing the position of the ink meniscus and causing the ink droplets to fly by using the two thermal energy acting units of the present invention.

FIG. 16 is an explanatory diagram for using the two thermal energy acting portions of the present invention to change the position of the ink meniscus and fly the ink droplet.

FIG. 17 is an explanatory diagram for changing the position of the ink meniscus and causing the ink droplets to fly by using the two thermal energy acting units of the present invention.

FIG. 18 is an explanatory diagram showing an outline of an on-demand type inkjet system using an electrostrictive oscillator to which the present invention can be applied.

19A and 19B are explanatory views for explaining the embodiment of FIG. 9 as a specific example, FIG. 19A is a top view, and FIG. 19B is a side view.

20 is an explanatory diagram for explaining a specific example using the electrostrictive vibrator (piezo element) of FIG.

21 (a) to (g) are operation explanatory views of a bubble jet head to which the present invention is applied.

22 is a perspective view of the bubble jet head shown in FIG. 21. FIG.

23A and 23B are perspective views of the head of FIG. 2 exploded into a lid substrate and a heating element substrate.

FIG. 24 is a perspective view of the lid substrate shown in FIG. 23 (a) viewed from the back side.

25A and 25B are drawings for explaining a configuration of a main part of the liquid jet recording head, wherein FIG. 25A is a detailed front partial view seen from the ejection port side, and FIG. 25B is a dashed-dotted line xx of FIG. FIG. 4 is a partial sectional view of a portion indicated by.

FIG. 26 is a cross-sectional view for explaining the structure of a bubble generating portion that uses a heating resistor in the recording head.

[Explanation of symbols]

4A Discharge port with small cross-sectional area 4B Discharge port with large cross-sectional area 5 Flow path 9 Heating element (heater) 9A First heating element (heating element for ejection) 9B Second heating element (heating element for ink meniscus formation) 10 Ink 11 Bubble 12 Flying Ink Drop 49 Heater 53 Ink Container (Ink Supply Means) 56A First Electrostrictive Oscillator (Piezo Element) 56B Second Electrostrictive Oscillator (Piezo Element)

Claims (6)

[Claims] 1. A plurality of energy acting portions are provided for one discharge port, and the size of the cross-sectional area of the discharge port is changed, and an ink meniscus formed at the discharge port with the changed cross-sectional area is formed. An ink jet recording method, wherein the position can be changed by operating at least one energy application part of the plurality of energy application parts to eject ink droplets having different masses or diameters from a single ejection port. 2. A single energy acting portion is provided for one discharge port, and the size of the cross-sectional area of the discharge port is changed, and an ink meniscus formed at the discharge port with the changed cross-sectional area is formed. An ink jet recording method characterized in that a position can be changed by changing a water head difference between an ink supply means and an ejection port, and ink droplets having different masses or diameters can be ejected from a single ejection port. 3. An ink supply unit, a liquid chamber that guides ink from the ink supply unit, a flow path that guides ink from the liquid chamber to each ejection port, and a flow path that is arranged along each flow path, each of which is independent. A single energy application part or a plurality of energy application parts that can be driven, an ejection port for ejecting ink having a changed cross-sectional area provided at each flow path end, and an ink meniscus formed in the ejection port. An ink jet recording head comprising means for changing a position. 4. The ink jet recording head according to claim 3, wherein the ejection port having a changed cross-sectional area has a cross-sectional area changed from a small side to a large side from the energy acting portion side toward the flow path end side. . 5. An ink jet recording head provided with a single energy acting portion for changing the generation position of an ink meniscus at an ejection port having a changed cross-sectional area, and the ink supply means of the ink supply means with respect to the height of the ejection port. The ink jet recording head according to claim 3, further comprising means for changing the height. 6. In an ink jet recording head having a plurality of energy acting portions for changing a position where an ink meniscus is generated at an ejection port having a changed cross-sectional area, at least one of the plurality of energy acting portions is provided. 4. The ink jet recording head according to claim 3, wherein the energy acting portion of the section operates for switching the position of the ink meniscus.