JP2000062174A - Liquid ejection head, liquid ejecting method and liquid ejector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge residual bubbles in a liquid channel well from an ejection opening. SOLUTION: The liquid ejection head comprises a liquid ejection opening 18 communicating with a liquid channel 10 having a bubble generating region, a movable member 31 having free end 32 in the bubble generating region and being displaced as a bubble 40 grows, and a stopper 64 for regulating displacement of the movable member 31 within a desired range. The liquid ejection head further comprises a mechanism for transferring a bubble 68 in the liquid channel 10 by generating a liquid flow from a gap between the movable member 31 and a stopper 64 along a plane facing a heating element 2 during a process for suppressing the bubble 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejecting method, a liquid ejecting head, and a liquid ejecting apparatus for ejecting a desired liquid by generating bubbles by applying heat energy to the liquid. The present invention relates to a liquid ejecting head, a liquid ejecting method, and a liquid ejecting apparatus that use a movable member that is displaced by utilizing the above.

The present invention also provides a printer for performing recording on a recording medium such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood and ceramics, a copying machine, a facsimile having a communication system, and a printer. The present invention can be applied to a device such as a word processor having a unit, and further to an industrial recording device that is combined with various processing devices.

In the present invention, "recording" means not only giving an image having a meaning such as characters and figures to a recording medium, but also giving an image having no meaning such as a pattern. Also means.

[0004]

2. Description of the Related Art By applying energy such as heat to ink, a state change accompanied by a sharp volume change (generation of bubbles) is caused in the ink, and the ink is ejected from an ejection port by an action force based on the state change. An ink jet recording method, which is a so-called bubble jet recording method, in which an image is formed by adhering this onto a recording medium is conventionally known. In a recording apparatus using this bubble jet recording method, as disclosed in US Pat. No. 4,723,129, an ejection port for ejecting ink and an ink flow communicating with this ejection port are disclosed. The channels and the electrothermal converters as energy generating means for ejecting the ink disposed in the ink flow paths are generally disposed.

According to such a recording method, it is possible to record a high-quality image at high speed and with low noise, and in the head performing this recording method, the ejection openings for ejecting ink are arranged at high density. Therefore, it has many excellent points that a high-resolution recorded image and a color image can be easily obtained with a small apparatus. Therefore, in recent years, this bubble jet recording method has been used in many office devices such as printers, copying machines, and facsimiles, and has also come to be used in industrial systems such as textile printing devices.

As the bubble jet technology has been used for products in various fields as described above, various requirements as described below have been further increased in recent years.

In order to obtain a high-quality image, driving conditions have been proposed for providing a liquid ejection method, etc., in which the ink ejection speed is fast and good ink ejection can be performed based on stable bubble generation, or high-speed recording is performed. From this point of view, there has been proposed a liquid flow head having an improved flow path shape in order to obtain a liquid discharge head having a high filling (refill) speed of the discharged liquid into the liquid flow path.

[0008]

By the way, in the conventional liquid discharge head in which the cross-sectional area of the liquid flow path in the bubble generation region is sufficiently provided, the liquid flow path is covered with the liquid on the opposite surface of the heating element of the liquid flow path. Dissolved gas will be deposited and the generated dissolved bubbles will adhere, and the growth of these dissolved bubbles will reduce the energy at the time of bubble generation, causing phenomena such as reduced discharge volume and non-discharge. was there. However, there is a portion where the liquid flow stagnates on the surface of the liquid flow path that faces the heating element, and the dissolved bubbles cannot be discharged during normal liquid discharge.

Therefore, conventionally, when the dissolved bubbles are accumulated in the bubble generation region, the dissolved bubbles are discharged together with the liquid by a recovery process such as suction recovery before the discharge is affected in advance. However, this recovery process is not preferred to be performed too often, as it involves draining more liquid than is normally required.

In the present invention, the accumulation itself of the dissolved bubbles is fundamentally reviewed, and the dissolved bubbles are prevented from disappearing or accumulated in a large amount by a simple structure, and the liquid can be satisfactorily ejected without performing the recovery process. An object of the present invention is to provide a liquid ejection head, a liquid ejection method, and a liquid ejection device that can significantly extend the period of time that can be performed.

[0011]

In order to achieve the above object, a liquid ejection head of the present invention is a heating element for generating thermal energy for generating bubbles in the liquid, and a portion for ejecting the liquid. A discharge port, a liquid flow path communicating with the discharge port and having a bubble generation region for generating bubbles in the liquid; a movable member provided in the bubble generation region and displaced as the bubble grows; A liquid ejecting head, comprising: a regulating unit that regulates a displacement of a member within a desired range, and ejecting the liquid from the ejection port by energy when the bubble is generated, wherein the regulating unit is the bubble of the liquid flow path. In the liquid flow path, the liquid flow path is provided above the generation area and causes a liquid flow along the surface of the liquid flow path facing the heating element from the gap between the movable member and the restriction portion during the bubble defoaming step. Transfer bubbles It characterized by having a bubble transport mechanism that.

Further, according to the liquid discharge method of the present invention, a heating element for generating thermal energy for generating bubbles in the liquid, a discharge port for discharging the liquid, and the discharge port are connected to each other. A liquid flow path having a bubble generation region for generating bubbles in the liquid, a movable member provided in the bubble generation region and displaced with the growth of the bubbles, and a regulation for regulating the displacement of the movable member within a desired range A liquid discharge method using a liquid discharge head that discharges the liquid from the discharge port by the energy at the time of bubble generation, wherein the restriction unit is provided above the bubble generation region of the liquid flow path. In the liquid flow path, a liquid flow along the surface of the liquid flow path facing the heating element is generated from the gap between the movable member and the restriction portion during the bubble defoaming step. Transfer bubbles It characterized by having a step.

According to the present invention, even when bubbles remain in the liquid flow path, the bubbles are discharged to the discharge port by the liquid flow generated by the gap between the movable member and the restriction portion in the liquid flow path. The liquid is guided and discharged from the discharge port to the outside of the liquid flow path. Therefore, the bubbles remaining in the liquid flow path do not cause a problem such as a decrease in discharge amount or non-discharge, and a stable discharge state can be maintained.

Further, the liquid ejecting apparatus of the present invention comprises the above-mentioned liquid ejecting head of the present invention, and a recording medium conveying means for conveying a recording medium that receives the liquid ejected from the liquid ejecting head.

Further, the liquid ejecting apparatus may be configured to eject ink from the liquid ejecting head and adhere the ink to the recording medium to perform recording.

Further, the "substantial contact" between the movable member and the regulating portion used in the present invention means that the movable member and the regulating portion are in direct contact with each other even when a liquid of about several μm is interposed between them. May be.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the liquid discharge head of the present invention taken along the liquid flow path, showing characteristic phenomena in the liquid flow path of (a) to (f). It is shown divided into steps.

In the liquid ejecting head of this embodiment, as the ejection energy generating element for ejecting the liquid, the heating element 2 for exerting heat energy on the liquid is provided on the smooth element substrate 1, and on the element substrate 1. The liquid flow path 10 is arranged corresponding to the heating element 2. The liquid flow path 10 is in communication with the discharge port 18 and also with the common liquid chamber 13 for supplying liquid to the plurality of liquid flow paths 10, and has an amount commensurate with the liquid discharged from the discharge port 18. The liquid is received from this common liquid chamber 13. Reference symbol M represents a meniscus formed by the discharge liquid,
The meniscus M is balanced in the vicinity of the discharge port 18 with respect to the internal pressure of the common liquid chamber 13, which is usually a negative pressure due to the capillary force generated by the discharge port 18 and the inner wall of the liquid flow path 10 communicating with the discharge port 18.

The liquid flow path 10 is constructed by joining the element substrate 1 provided with the heating element 2 and the top plate 50, and heat is generated in the area near the surface where the heating element 2 and the discharge liquid are in contact with each other. There is a bubble generation region 11 in which the body 2 is rapidly heated to cause foaming in the discharged liquid. At least a part of the movable member 31 is arranged in the liquid flow path 10 having the bubble generation region 11 so as to face the heating element 2. The movable member 31 has a free end 32 on the downstream side toward the discharge port 18, and is supported by a support member 34 arranged on the upstream side. In particular, in this embodiment, the free end 32 is arranged near the center of the bubble generation region 11 in order to suppress the growth of the upstream half of the bubble that affects the back wave to the upstream side and the inertial force of the liquid. The movable member 31 can be displaced with respect to the support member 34 as the bubbles generated in the bubble generation region 11 grow. The fulcrum 33 at the time of this displacement serves as a support portion of the movable member 31 in the support member 34.

A stopper (regulating portion) 64 is located above the center of the bubble generating region 11 and regulates the displacement of the movable member 31 within a certain range in order to suppress the growth of the upstream half of the bubble. The stopper 64 is the movable member 3 of the liquid flow path 10.
It is formed by partially reducing the distance from 1. In the flow from the common liquid chamber 13 to the discharge port 18, a low flow path resistance region 65 having a flow path resistance relatively lower than that of the liquid flow path 10 is provided on the upstream side of the stopper 64 as a boundary. The flow channel structure in this region 65 has no upper wall or has a large flow channel cross-sectional area, so that the resistance received from the flow channel with respect to the movement of the liquid is reduced.

Next, the ejection operation of the liquid ejection head of this embodiment will be described in detail.

FIG. 1A shows a state before energy such as electric energy is applied to the heating element 2 and shows a state before the heating element generates heat. The important thing here is
The movable member 31 is provided at a position facing the upstream half of the bubble generated by the heat generated by the heating element 2, and the stopper 64 for restricting the displacement of the movable member 31 has a bubble generation region 11 It is provided above the center of the. That is, depending on the liquid flow path structure and the arrangement position of the movable member, the upstream half of the bubble is pressed into the movable member 31.

FIG. 1 (b) shows a state in which a part of the liquid filling the bubble generating region 11 is heated by the heating element 2 and the bubbles 40 accompanying the film boiling are maximally grown. At this time,
The liquid in the liquid flow path 10 moves to the downstream side and the upstream side by the pressure based on the generation of the bubbles 40, and the bubbles 4
The movable member 31 is displaced by the growth of 0, and the discharge droplet 66 is about to be ejected from the discharge port 18 on the downstream side.
Here, the movement of the liquid toward the upstream side, that is, the direction of the common liquid chamber 13 becomes a large flow due to the low flow path resistance region 65,
When the movable member 31 is displaced until the vicinity of the free end 32 approaches or contacts the stopper 64, further displacement is restricted, so that the movement of the liquid in the upstream direction is also greatly restricted. At the same time, the growth of the bubbles 40 on the upstream side is also limited by the movable member 31. However, since the moving force of the liquid in the upstream direction is large, the movable member 31 receives a large amount of stress in the form of being pulled in the upstream direction. Furthermore, a part of the bubble 40, the growth of which is restricted by the movable member 31, is partially removed from the liquid flow path 10.
Passing through a slight gap between the side walls of the movable member 31 and the side portion of the movable member 31, and is raised to the upper surface side of the movable member 31. This raised bubble will be referred to as "raised bubble (41)" in the present specification.

In the present invention, as shown in FIG. 2, between the discharge port side portion of the bubble 40 and the discharge port is a "linear communication state" in which a straight flow path structure is maintained with respect to the liquid flow. ing. More preferably, this is because the propagating direction of the pressure wave generated when the bubbles are generated and the liquid flowing direction and the ejecting direction corresponding to the propagating direction are linearly aligned with each other, so that the ejecting state of the ejected droplet 66, the ejecting speed, and the like. It is desirable to create the ideal state of stabilizing V at a very high level.
In the present invention, as one definition for achieving or approximating this ideal state, the discharge port 18 and the heating element 2, particularly the discharge port side (downstream side) of the heating element having an influence on the discharge port side of bubbles are Can be directly connected by a straight line. This is a state where the heating element, especially the downstream side of the heating element can be observed when viewed from the outside of the discharge port if there is no fluid in the flow path. Is.

FIG. 1 (c) shows a state in which the negative pressure inside the bubble overcomes the movement of the liquid to the downstream side in the liquid flow path after the film boiling described above, and the contraction of the bubble 40 is started. At this point in time, since a large amount of liquid is left in the upstream direction due to bubble growth, the movable member 31 is still substantially in contact with the stopper 64 for a certain period after the contraction of the bubble 40 starts. Most of the contraction causes liquid movement from the discharge port 18 in the upstream direction. That is, immediately after the stage shown in FIG. 1B, the liquid flow path 10 having the bubble generation region 11 is substantially removed except the discharge port 18 due to the substantial contact between the displaced movable member 31 and the stopper 64. Since it is a closed space, the contraction energy of the bubble 40 is
It works as a force to move the nearby liquid in the upstream direction. Therefore, at this point, the meniscus M is largely drawn into the liquid flow path 10 from the ejection port 18, and the liquid column connected to the ejection droplet 66 is quickly separated with a strong force. As a result, as shown in FIG. 1D, the number of droplets, that is, satellites (sub droplets) 67 left outside the ejection port 18 decreases.

FIG. 1 (d) shows a state in which the discharge bubble 66 and the meniscus M are separated after the defoaming process is completed. In the low flow path resistance region 65, the repulsive force of the movable member 31 exceeds the moving force of the liquid in the upstream direction, and the downward displacement of the movable member 31 and the subsequent flow in the low flow path resistance region 65 in the downstream direction start. To be done. At the same time, the flow in the downstream direction in the low flow resistance region 65 has a small flow resistance, so that it rapidly becomes a large flow and flows into the liquid flow path 10 via the stopper 64 portion. As a result, the flow that rapidly draws the meniscus M into the liquid flow path 10 suddenly decreases, so that the meniscus M draws the liquid column portion remaining outside from the discharge port 18 to a position before foaming at a relatively low speed. Start returning.

Further, in the liquid flow path 10 of the liquid discharge head, the gas contained in the liquid or the gas which has not been completely defoamed after the firing may remain like bubbles 68. When the bubbles 68 grow and occupy a large volume in the liquid flow path 10, a discharge amount is reduced or a discharge failure occurs. In some cases, the energy application to the heating element 2 is continued without a liquid, and It causes the disconnection of 2. However, in the liquid ejection head of this embodiment, the meniscus M
Since the stopper 64 suppresses the flow toward the ceiling side of the liquid flow path 10 when the pressure is restored, and the movable member 31 is displaced toward the ceiling side of the liquid flow path 10, the stopper 64 causes the discharge port 1 to move.
The liquid begins to move radially in eight directions, and the liquid flow path 1
A liquid flow is generated along the 0 ceiling (the surface facing the heating element 2). As described above, in the liquid ejection head of the present embodiment, a liquid flow is generated from the gap between the movable member 31 and the stopper 64 along the surface of the liquid flow path 10 facing the heating element 2 during the defoaming process of the bubbles 40. A bubble transfer mechanism that transfers the bubbles in the liquid flow path 10 is configured.

On the other hand, the ejected droplet 66 and the satellite 67 existing immediately thereafter are very close to each other due to the rapid meniscus drawing in FIG. A phenomenon called a slipstream phenomenon occurs, which receives a force attracted.

FIG. 1 (e) shows a further advanced state of FIG. 1 (d). The bubbles 68 are guided to the ejection port 18 along the surface of the element substrate 1 by the flow accompanying the liquid flow generated in the liquid flow path 10 as described above. Further, the satellite 67 further approaches the ejected droplet 66 and is attracted at the same time, and the attractive force due to the slipstream phenomenon also increases.
On the other hand, in the movement of the liquid from the upstream side toward the ejection port 18, the displacement overshoot of the movable member 31 causes displacement below the initial position, whereby the liquid is drawn in from the upstream side and the ejection port 1 is discharged.
The liquid is extruded in eight directions. Moreover,
The increase in the cross-sectional area of the liquid flow path in which the stopper 64 is present increases the liquid flow in the direction of the ejection port 18 and accelerates the return of the meniscus M to the ejection port 18. As a result, the refill characteristics in this embodiment are dramatically improved.

FIG. 1 (f) shows a further advanced state of the state of FIG. 1 (e). Bubbles 68 led to the discharge port 18
Are discharged from the discharge port 18 to the outside of the liquid flow path 10. Therefore, the bubbles 68 remaining in the liquid flow path 10 do not cause a problem such as a decrease in discharge amount or non-discharge, and it is possible to maintain a stable discharge state.

Although FIG. 1 (f) shows a state in which the satellite 67 is taken into the discharge droplet 66, the combination of the discharge droplet 66 and the satellite 67 does not always occur for each discharge in other embodiments. Instead, it may or may not happen depending on the conditions. However, by at least reducing or eliminating the amount of satellites, the landing positions of the main droplets and satellite dots hardly shift on the recording medium, and the influence on print quality becomes extremely small. That is, the sharpness of the image can be enhanced to improve the printing quality, and the harmful effects such as becoming a mist and contaminating the inside of the printing medium or the recording apparatus can be reduced.

On the other hand, the movable member 31 is displaced in the direction of the stopper 64 again by the reaction of the overshoot.
This converges due to the damping vibration determined by the shape and Young's modulus of the movable member 31, the viscosity of the liquid in the liquid flow path, and the specific gravity, and finally stops at the initial position.

The upward displacement of the movable member 31 controls the flow of liquid from the common liquid chamber 13 side toward the discharge port 18,
The movement of the meniscus M quickly converges near the discharge port. Therefore, it is possible to greatly reduce the factors such as the overshoot phenomenon of the meniscus, which makes the ejection state unstable and deteriorates the printing quality.

Next, further characteristic effects of this embodiment will be described.

FIG. 3 is a perspective view of a part of the head shown in FIG. 1B, which basically shows the same state as that of FIG. 1B except that the nozzle is seen through and shown by a broken line. is there. In this embodiment, there is a slight clearance between both side wall surfaces of the wall forming the liquid flow path 10 and both side portions of the movable member 31 to allow the movable member 31 to be smoothly displaced.
Further, in the step of growing foam by the heating element 2, the bubble 40 displaces the movable member 31 and bulges toward the upper surface side of the movable member 31 through the clearance and slightly enters the low flow path resistance region 65. This rising bubble 41
Wraps around the back surface of the movable member 31 (the surface opposite to the bubble generation region 11) to suppress the blurring of the movable member 31 and stabilize the ejection characteristics.

Further, in the defoaming process of the bubbles 40, the raised bubbles 41 are transferred from the low flow path resistance region 65 to the bubble generation region 11
The liquid flow to the nozzle is accelerated, and the defoaming is promptly completed in combination with the above-described high-speed drawing of the meniscus from the discharge port 18 side. In particular, the liquid flow caused by the raised bubbles 41 hardly accumulates the bubbles in the movable member 31 or the corners of the liquid flow path 10.

(Other Embodiments) Various embodiments applicable to the head using the above-described liquid ejecting method will be described below.

<Movable Member> FIG. 4 shows another shape of the movable member 31. The figure (a) is a rectangular shape, the figure (b) is a shape in which the fulcrum side is narrow and the shape of the movable member is easy to operate, and the figure (c) is wide in the fulcrum side and the movable member is The shape improves the rigidity of the.

In the previous embodiment, the movable member 31 was made of nickel having a thickness of 5 μm. However, the material of the movable member is not limited to this, it has solvent resistance to the discharge liquid, and is movable. Any member may be used as long as it has elasticity so that it can operate well as a member.

As the material of the movable member 31, silver, nickel, gold, iron, titanium, aluminum, which has high durability,
Metals such as platinum, tantalum, stainless steel, phosphor bronze, and their alloys, or acrylonitrile, butadiene,
Resins having nitrile groups such as styrene, resins having amide groups such as polyamide, resins having carboxyl groups such as polycarbonate, resins having aldehyde groups such as polyacetal, resins having sulfone groups such as polysulfone, and other liquid crystal polymers, etc. Resin and its compounds,
Metals with high ink resistance such as gold, tungsten, tantalum, nickel, stainless steel, and titanium, alloys of these, and those having ink resistance coated on the surface, resins having amide groups such as polyamide, polyacetal, etc. Resin having aldehyde group, resin having ketone group such as polyetheretherketone, resin having imide group such as polyimide, resin having hydroxyl group such as phenol resin, resin having ethyl group such as polyethylene, alkyl such as polypropylene Resin with a base,
A resin having an epoxy group such as an epoxy resin, a resin having an amino group such as a melamine resin, a resin having a methylol group such as a xylene resin and a compound thereof, and a ceramic such as silicon dioxide and silicon nitride and a compound thereof are preferable.
The thickness of the μm order is targeted as the movable member 31 in the present invention.

Next, the positional relationship between the heating element and the movable member will be described. By the optimal arrangement of the heating element and the movable member,
It is possible to appropriately control the flow of the liquid at the time of foaming by the heating element and effectively use the liquid.

By giving energy such as heat to the ink, a state change accompanied by a sharp volume change (generation of bubbles) is caused in the ink, and the action force based on this state change ejects the ink from the ejection port. In the conventional ink jet recording method, that is, a so-called bubble jet recording method, in which an image is formed by adhering the ink onto a recording medium, the method shown in FIG.
As shown in (1), it can be seen that there is a non-foaming effective region S that does not contribute to ink ejection, although the heating element area and the ink ejection amount are in a proportional relationship. Further, from the state of kogation on the heating element, it can be seen that the non-foaming effective area S exists around the heating element. From these results, it is considered that the width of about 4 μm around the heating element is not involved in foaming.

Therefore, in order to effectively use the foaming pressure, the region directly above the foaming effective region of about 4 μm or more from the periphery of the heating element is the region where the movable member effectively acts,
In the case of the present invention, the action of the bubbles on the upstream side and the downstream side of the substantially central region of the bubble generation region (actually within a range of ± about 10 μm in the liquid flow direction from the center) on the liquid flow in the liquid passage is independently performed. Focusing on the distinction between the actuating stage and the synthetic actuating stage, it is extremely important to dispose the movable member such that only the upstream side portion of the central region faces the movable region of the movable member. I can say. In the present embodiment, the effective foaming area is set to be approximately 4 μm or more inside from the periphery of the heating element, but it is not limited to this depending on the kind of the heating element and the forming method.

<Element Substrate> Next, the structure of the element substrate will be described.

6A and 6B are vertical sectional views of the liquid discharge head of the present invention. FIG. 6A shows a head having a protective film, which will be described later, and FIG. 6B, which does not have a protective film.

The liquid flow path 10, the discharge port 18 communicating with the liquid flow path 10, the low flow path resistance region 65, and the top plate 50 provided with the groove forming the common liquid chamber 13 are arranged on the element substrate 1. .

The element substrate 1 has a base 107 made of silicon or the like.
A silicon oxide film or a silicon nitride film 106 for the purpose of insulation and heat storage is formed on the film, and hafnium boride (HfB2), tantalum nitride (TaN), and tantalum aluminum (TaAl) that constitute the heating element 2 are formed thereon. 6) and the electric resistance layer 105 (0.01 to 0.2 μm thick) and the wiring electrode 104 (0.2 to 1.0 μm thick) such as aluminum are patterned as shown in FIG. 6A. A voltage is applied from the wiring electrode 104 to the resistance layer 105, and a current is passed through the resistance layer to generate heat. A protective layer 103 made of silicon oxide, silicon nitride, or the like is formed on the resistance layer between the wiring electrodes by 0.1 to 0.1%.
It is formed to a thickness of 2.0 μm, and a cavitation resistant layer 102 (0.1 to 0.6 μm thick) such as tantalum is further formed thereon.
The resistance layer 1 is formed from various liquids such as ink.
05 is protected.

In particular, the pressure and shock waves generated when bubbles are generated and defoamed are extremely strong, and the durability of a hard and brittle oxide film is significantly reduced. Therefore, tantalum (Ta), which is a metal material, is used.
Etc. are used as the anti-cavitation layer 102.

Further, depending on the combination of the liquid, the liquid flow path structure, and the resistance material, the above-mentioned resistance layer 105 may not have the protective layer 103, and an example thereof is shown in FIG. 6 (b). Examples of the material of the resistance layer 105 that does not require the protective layer 103 include iridium-tantalum-aluminum alloy.

As described above, as the constitution of the above-mentioned heating element, only the above-mentioned resistance layer (heating portion) between the electrodes may be used.
It may also include a protective layer for protecting the resistance layer.

Although a heating element having a heating portion composed of a resistance layer that generates heat in response to an electric signal is used here, the heating element is not limited to this, and bubbles sufficient to eject the ejection liquid are used. Any material can be used as long as it can be generated in the foaming liquid.
For example, the heat generating portion may be a photothermal converter that generates heat when receiving light from a laser or the like, or a heat generating body that has a heat generating portion that generates heat when receiving high frequency.

On the element substrate 1 described above, in addition to the electrothermal converter constituted by the resistance layer 105 forming the heat generating section and the wiring electrode 104 for supplying an electric signal to the resistance layer, Functional elements such as a transistor, a diode, a latch, and a shift register for selectively driving the electrothermal conversion element may be integrally formed in the semiconductor manufacturing process.

Further, in order to drive the heat generating portion of the electrothermal converter provided on the element substrate 1 as described above and eject the liquid, the resistance layer 105 is connected to the resistance layer 105 via the wiring electrode 104 as shown in FIG. A rectangular pulse as shown by is applied to rapidly generate heat in the resistance layer 105 between the wiring electrodes. In the head of each of the above-described embodiments, the voltage is 24 V, the pulse width is about 4 μsec, the current is about 100 mA, and the electric signal is 6 kHz.
By adding the above, the heating element was driven, and the liquid ink was ejected from the ejection port by the above-described operation. However, the condition of the drive signal is not limited to this, and any drive signal capable of appropriately foaming the foaming liquid may be used.

<Discharge Liquid> Among these liquids, as the liquid (recording liquid) used for recording, the ink having the composition used in the conventional bubble jet device can be used.

Further, it is possible to use a liquid having a low foaming property which has been difficult to be ejected conventionally, a liquid which is easily deteriorated or deteriorated by heat, a high viscosity liquid and the like.

However, as the properties of the discharge liquid, the discharge liquid itself is
It is desired that the liquid is not a liquid that hinders ejection, foaming, movement of the movable member, or the like.

High-viscosity ink or the like can also be used as the ejection liquid for recording.

In the present invention, recording was performed using an ink having the following composition as a recording liquid that can be used as the discharging liquid. However, since the discharging speed of the ink increased due to the improvement of the discharging force, the liquid was discharged. The landing accuracy of the drops is improved, and a very good recorded image can be obtained.

[0060] Composition of dye ink (viscosity 2 cP) (C-1. Food Black 2) Dye 3% by weight Diethylene glycol 10% by weight Thiodiglycol 5% by weight Ethanol 5% by weight 77% by weight of water

<Structure of Liquid Discharging Head> FIG. 8 is an exploded perspective view showing the overall structure of the liquid discharging head of the present invention.

An element substrate 1 having a plurality of heating elements 2 is provided on a support 70 made of aluminum or the like. A support member 34 that supports the movable member 31 is provided thereon so as to face the half of each heating element 2 on the common liquid chamber 13 side. Further, a top plate 50 provided with a plurality of grooves forming the liquid flow path 10 and concave grooves of the common liquid chamber 13 is provided thereon.

<Side Shooter Type> Here, FIG.
Also, the liquid ejection principle described with reference to FIG. 3 is applied to a side shooter type head in which a heating element and an ejection port face each other on a parallel plane. FIG. 9 is a diagram for explaining this side shooter type head.

In FIG. 9, the heating element 2 on the element substrate 1 and the discharge port 18 formed on the top plate 50 are arranged so as to face each other. The discharge port 18 is the liquid flow path 1 passing over the heating element 2.
It communicates with 0. A bubble generation region exists in a region near the surface where the heating element 2 contacts the liquid. Two movable members 31 are supported on the element substrate 1, each movable member is formed so as to be plane-symmetric with respect to a plane passing through the center of the heating element, and the free end of each movable member 31 is The heating elements 2 are located so as to face each other. In addition, each movable member 3
1 has the same projected area on the heating element 2, and the free ends of the movable members 31 are separated by a desired size. Here, each movable member is provided so that the free end of the movable member is located near the center of each divided heating element, assuming that the movable member is divided by the dividing wall of the surface passing through the center of the heating element. There is.

The top plate 50 is provided with a stopper 64 for restricting the displacement of each movable member 31 within a certain range. In the flow from the common liquid chamber 13 to the discharge port 18, the stopper 64
A low flow path resistance region 65 having a flow path resistance relatively lower than that of the liquid flow path 10 is provided on the upstream side of the boundary. The flow channel structure in this region 65 has a flow channel cross-sectional area larger than that of the liquid flow channel 10, and thus reduces the resistance received from the flow channel with respect to the movement of the liquid.

Next, the characteristic operation of the structure of this embodiment
Explain the effect.

FIG. 9A shows a state in which a part of the liquid filling the bubble generating region 11 is heated by the heating element 2 and the bubbles 40 accompanying the film boiling are maximally grown. At this time,
The liquid in the liquid flow path 10 moves toward the discharge port 18 due to the pressure generated by the generation of the bubble 40, the movable members 31 are displaced by the growth of the bubble 40, and the discharge droplet 66 is about to fly out from the discharge port 18. Here, the movement of the liquid in the direction of the common liquid chamber 13 becomes a large flow due to the respective low flow path resistance regions 65, but when the two movable members 31 are displaced until they come close to or come into contact with the respective stoppers 64, further movement will occur. Since the displacement is regulated, the movement of the liquid in the common liquid chamber 13 direction is also greatly restricted there. At the same time, the growth of the bubbles 40 on the upstream side is also limited by the movable member 31. However, since the moving force of the liquid in the upstream direction is large, a part of the bubbles 40, the growth of which is restricted by each movable member 31, may be generated in the gap between the side wall forming the liquid flow path 10 and the side portion of the movable member 31. Street, movable member 31
Is raised on the upper surface side of. That is, the raised bubbles 41 are formed.

When the contraction of the bubble 40 is started after the film boiling, since a large force of the liquid in the upstream direction remains at this point, each movable member 31 is still substantially in contact with the stopper 64. Yes, most of the contraction of the bubbles 40 causes liquid to move from the discharge port 18 in the upstream direction. Therefore, at this point, the meniscus is discharged from the discharge port 18 to the liquid flow path 1
The liquid column that is largely drawn into 0 and is connected to the ejected droplet 66 is quickly separated with a strong force. As a result, the discharge port 1
There are less droplets or satellites left outside 8.

When the defoaming process is almost completed, the movable member 3 is moved in each low flow path resistance region 65 against the moving force of the liquid in the upstream direction.
The repulsive force (restoring force) of 1 prevails, and the downward displacement of the movable member 31 and the subsequent flow in the low flow path resistance region 65 in the downstream direction are started. At the same time, the flow in the downstream direction in the low flow resistance region 65 has a small flow resistance, so that it rapidly becomes a large flow and flows into the liquid flow path 10 via the stopper 64 portion. FIG. 9B shows a liquid flow AB in the defoaming process of the bubbles 40. Liquid flow A is common liquid chamber 13
Shows the component that the liquid from flows through the upper surface (the surface opposite to the heating element) of the movable member 31 toward the discharge port 18, and the liquid flow B shows the component that flows on both sides of the movable member 31 and on the heating element 2. Shows.

As described above, in this embodiment, the refilling property is enhanced at a higher speed by supplying the ejection liquid from the low flow path resistance region 65. Further, since the common liquid chamber 13 adjacent to the low flow path resistance region 65 has the flow path resistance further reduced, high speed refilling is possible.

Further, in the defoaming process of the bubbles 40, the raised bubbles 41 move from the low flow path resistance regions 65 to the bubble generation region 1
The liquid flow to No. 1 is promoted, and the defoaming is promptly completed in combination with the above-described high-speed drawing of the meniscus from the discharge port 18 side. In particular, the liquid flow caused by the raised bubbles 41 hardly accumulates the bubbles in the movable member 31 or the corners of the liquid flow path 10.

<Liquid Ejecting Device> FIG. 10 shows a schematic structure of a liquid ejecting device equipped with the liquid ejecting head having the structure described with reference to FIGS. 1 and 9. In this embodiment, an ink discharge recording apparatus using ink as a discharge liquid will be described in particular. A carriage HC of the liquid ejecting apparatus is equipped with a head cartridge to which a liquid tank section 90 containing ink and a liquid ejecting head section 200 can be attached and detached, and a recording medium such as a recording sheet conveyed by a recording medium conveying means is mounted. Recording medium 15
It reciprocates in the width direction of 0.

When a drive signal is supplied from the drive signal supply means (not shown) to the liquid ejection means on the carriage, the recording liquid is ejected from the liquid ejection head onto the recording medium in response to this signal.

Further, in the liquid ejecting apparatus of this embodiment, the motor 111 as a drive source for driving the recording medium conveying means and the carriage, the gears 112, 113 for transmitting the power from the drive source to the carriage, It has a carriage shaft 115 and the like. With this recording apparatus and the liquid ejecting method performed by this recording apparatus, it is possible to obtain a recorded image with a good image by ejecting liquid onto various recording media.

FIG. 11 is a block diagram of the entire apparatus for operating the ink ejection recording in the liquid ejection method and liquid ejection head of the present invention.

The recording device receives print information from the host computer 300 as a control signal. The print information is temporarily stored in the input interface 301 inside the printer, and at the same time, converted into data that can be processed in the recorder and input to the CPU 302 which also serves as a head drive signal supply means. The CPU 302 processes the data input to the CPU 302 using a peripheral unit such as the RAM 304 based on a control program stored in the ROM 303,
Convert to print data (image data).

Further, the CPU 302 produces drive data for driving a drive motor that moves the recording sheet and the recording head in synchronization with the image data in order to record the image data at an appropriate position on the recording sheet. . The image data and the motor drive data are respectively sent to the head driver 307.
Is transmitted to the head 200 and the drive motor 306 via the motor driver 305, and driven at each controlled timing to form an image.

The recording medium which can be applied to the recording apparatus as described above and to which liquid such as ink is applied is various kinds of paper, OHP sheets, plastic materials used for compact discs, decorative plates and the like, cloth, aluminum. Metal materials such as copper and copper, leather materials such as cowhide, pigskin and artificial leather, wood materials such as wood and plywood, bamboo materials, ceramic materials such as tiles, and three-dimensional structures such as sponges can be targeted.

Further, as the above-mentioned recording device, a printer device for recording on various kinds of paper or OHP sheets, a recording device for plastics for recording on a plastic material such as a compact disc, a metal for recording on a metal plate, etc. Recording device, recording device for leather for recording on leather, recording device for wood for recording on wood, recording device for ceramics for recording on ceramic material, recording device for recording on three-dimensional mesh structure such as sponge It also includes a printing device for recording on the cloth.

As the ejection liquid used in these liquid ejection devices, a liquid suitable for each recording medium and recording conditions may be used.

[0081]

As described above, according to the present invention,
When the liquid flows toward the discharge port through the gap between the movable member and the regulating portion that regulates the displacement of the movable member within a desired range,
Since the liquid flowing in the liquid flow path causes a liquid flow along the ceiling of the liquid flow path (the surface facing the heating element), the bubbles remaining in the liquid flow path are discharged from the discharge port to the outside of the liquid flow path. As a result, bubbles remaining in the liquid flow channel do not cause a problem such as a decrease in discharge amount or non-discharge, and a stable discharge state can be maintained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one embodiment of a liquid discharge head according to the present invention cut in the liquid flow channel direction, showing characteristic phenomena in the liquid flow channel in steps (a) to (f). It is shown separately.

FIG. 2 is a sectional view of a flow path for explaining a “linear communication state”.

FIG. 3 is a perspective view of a part of the head shown in FIG. 1 (b).

FIG. 4 is a diagram showing another shape of the movable member shown in FIG.

FIG. 5 is a graph showing a relative relationship between a heating element area and an ink ejection amount.

6A and 6B are vertical cross-sectional views of a liquid discharge head of the present invention, where FIG. 6A shows a protective film and FIG. 6B does not have a protective film.

FIG. 7 is a waveform diagram for driving a heating element used in the present invention.

FIG. 8 is an exploded perspective view showing the overall configuration of the liquid ejection head of the present invention.

FIG. 9 is a diagram for explaining a side shooter type head to which the liquid ejection method of the present invention is applied.

FIG. 10 is a diagram showing a schematic configuration of a liquid ejection apparatus equipped with the liquid ejection head having the structure described in FIGS. 1 and 9.

FIG. 11 is a block diagram of the entire apparatus for operating ink discharge recording in the liquid discharge method and liquid discharge head of the present invention.

[Explanation of symbols]

1 element substrate 2 heating element 10 liquid flow paths 11 Bubble generation area 13 Common liquid chamber 18 outlets 31 Movable member 32 Free end 33 fulcrum 34 Support member 40,68 bubbles 41 Raised bubbles 50 top plate 64 stopper 65 Low flow resistance area 66 ejected drops 67 satellites 70 Support 90 ink tank 102 Anti-cavitation layer 103 protective layer 104 wiring electrode 105 Resistance layer 106 silicon nitride film 107 base 111 motor 112, 113 gears 115 Carriage axis 150 recording media 200 heads 300 host computer 301 Input / output interface 302 CPU 303 ROM 304 RAM 305 motor driver 306 Drive motor 307 head driver

Continued front page    (72) Inventor Hiroyuki Sugiyama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Satoshi Shimazu             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Sadayuki Sugama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2C057 AF78 AG12 AG46 AG76 AJ03                       AJ04 BA03 BA04 BA13

Claims (9)

[Claims] 1. A heating element that generates thermal energy for generating bubbles in a liquid, a discharge port that discharges the liquid, and a discharge port that communicates with the discharge port and generate bubbles in the liquid. A liquid flow path having a bubble generation region, a movable member that is provided in the bubble generation region and is displaced as the bubble grows, and a regulation unit that regulates the displacement of the movable member within a desired range, and the bubble generation A liquid ejection head for ejecting the liquid from the ejection port by the energy of time, wherein the restriction portion is provided above the bubble generation region of the liquid flow path, and the movable member and the movable member are provided during the bubble defoaming step. A liquid discharge head, comprising a bubble transfer mechanism that transfers a bubble in the liquid flow path by generating a liquid flow along a surface of the liquid flow path facing the heating element from a gap between the liquid flow path and the restriction portion. 2. The liquid ejection head according to claim 1, wherein the movable member is provided to suppress only bubbles that grow in the upstream direction with respect to the flow of the liquid toward the ejection port. 3. The liquid ejection head according to claim 1, wherein the movable member has a free end, and the free end is located substantially in the center of the bubble generating region. 4. The liquid ejection head according to claim 3, wherein the movable member substantially contacts the regulation portion near the free end. 5. The flow path resistance of the liquid flow path during standby of the movable member is lower on the upstream side than on the downstream side with the restriction portion as a boundary. Liquid ejection head. 6. The liquid ejection head according to claim 1, wherein the regulating portion is formed by partially reducing a distance of the liquid flow path from the movable member. 7. A heating element that generates thermal energy for generating bubbles in a liquid, a discharge port that is a part that discharges the liquid, and a discharge port that communicates with the discharge port and generate bubbles in the liquid. A liquid flow path having a bubble generation region, a movable member that is provided in the bubble generation region and is displaced as the bubble grows, and a regulation unit that regulates the displacement of the movable member within a desired range, and the bubble generation A liquid discharge method using a liquid discharge head that discharges the liquid from the discharge port by the energy of time, wherein the restriction portion is provided above the bubble generation region of the liquid flow path, In the defoaming step, the step of generating a liquid flow along the surface of the liquid flow path facing the heating element from the gap between the movable member and the restriction portion, and transferring the bubbles in the liquid flow path. Characterized by Liquid ejection method. 8. A liquid, comprising: the liquid ejection head according to claim 1; and a recording medium conveyance unit that conveys a recording medium that receives the liquid ejected from the liquid ejection head. Discharge device. 9. The liquid ejection apparatus according to claim 8, wherein recording is performed by ejecting ink from the liquid ejection head and adhering the ink to the recording medium.