JP2000062175A - Liquid ejection head, liquid ejecting method and liquid ejector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel liquid ejection principle by suppressing generated bubbles and liquid on the ejection opening side and the supply side through the structure of a movable member and the entire liquid channel. SOLUTION: When a displaced movable member 31 touches a stopper 64, a liquid channel 10 having a bubble generating region 11 provides a substantially closed space except an ejection opening 18 and suppression of bubbles is started under closed space state. In such a liquid ejection head, the movable member 31 is displayed by bubbles generated in the bubble generating region 11 while being displaced by a piezoelectric element 34 about a fulcrum part 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejection head for ejecting a desired liquid by the generation of bubbles caused by the action of thermal energy on the liquid, a head cartridge using the liquid ejection head, and a liquid ejection device. In particular, the present invention relates to a liquid ejection head having a movable member that is displaced by utilizing the generation of bubbles, a head cartridge using the liquid ejection head, and a liquid ejection device.

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.

In addition to such a head, attention is paid to a back wave (pressure directed in the direction opposite to the direction toward the ejection port) generated with the generation of bubbles, and The invention of the structure for preventing is disclosed in JP-A-6-
No. 31918 (particularly FIG. 3). In the invention described in this publication, a triangular portion of a triangular plate member is opposed to a heater that generates bubbles. In the present invention, the back wave is temporarily and slightly suppressed by the plate member. However, since the correlation between the bubble growth and the triangular portion is not mentioned at all and there is no idea of it, the above invention includes the following problems.

That is, in the invention described in the above publication, since the heater is located at the bottom of the recess and cannot establish a linear communication with the discharge port, the droplet shape cannot be stabilized and the bubble growth is triangular. Since it is allowed around the top of the triangle, bubbles grow from one side of the triangular plate to the entire opposite side, and as a result, normal bubbles in the liquid as if the plate was not present. The growth of bubbles is completed. Therefore, the presence of the plate-shaped member has nothing to do with the grown bubbles. On the contrary, since the entire plate-shaped member is surrounded by bubbles, refilling the heater located in the recess causes turbulent flow during the bubble contraction stage, which causes the accumulation of minute bubbles in the recess, causing growth. The principle itself of discharging based on bubbles is disturbed.

On the other hand, EP Publication No. 436047A1 discloses
The invention proposes to alternately open and close a first valve that shuts off the area near the ejection port and the bubble generating portion, and a second valve that shuts off the air bubble generating portion and the ink supply portion completely. (EP 436047A1 FIGS. 4-9). However, in the present invention, since these three chambers are divided into two, the ink that follows the droplets becomes a large trail at the time of ejection, and compared with the normal ejection method in which bubble growth, contraction, and defoaming are performed. Therefore, the satellite dots are considerably increased (it is presumed that the effect of meniscus receding due to defoaming cannot be used). Further, at the time of refilling, the liquid is supplied to the bubble generation part along with the defoaming, but since the liquid cannot be supplied to the area near the discharge port until the next foaming occurs, not only is there a large variation in the discharged droplets. , The ejection response frequency is extremely small, and is not at a practical level.

[0011]

An invention using a movable member (a plate-like member having a free end closer to the discharge port than a fulcrum) that can effectively contribute to the discharge of liquid droplets is completely different from the above-mentioned prior art. , Have been proposed by the applicant of the present application. Among the inventions, Japanese Patent Laid-Open No. 9-48127 discloses an invention in which the upper limit of the displacement of the movable member is regulated in order to prevent the behavior of the movable member described above from being slightly disturbed. Further, JP-A-9-323420 discloses that, with respect to the movable member,
Disclosed is an invention in which the position of the common liquid chamber in the upstream is shifted to the free end side of the movable member; In these cases, the assumption that the invention was created was that the growth of bubbles was temporarily wrapped in the movable member and then opened to the discharge port side at once, so that the entire bubbles are associated with individual elements involved in droplet formation. No attention has been paid to their correlation.

As the next step, the applicant of the present invention has disclosed that
-24588, as an invention (acoustic wave) focusing on bubble growth by pressure wave propagation as an element related to liquid ejection,
An invention is disclosed in which a part of the bubble generation region is released from the movable member. However, even in the present invention, since attention is paid only to the growth of bubbles at the time of ejecting the liquid, no attention is paid to the individual elements relating to the formation of the droplets themselves as a whole and their correlations.

Although it is known that the front portion (edge shooter type) of bubbles due to film boiling which has been conventionally known has a great influence on ejection, this portion can contribute to formation of ejected droplets more efficiently. Nothing has hitherto been paid attention to this, and the present inventors have conducted diligent research in order to clarify the technical aspects of the present invention.

The present invention is one of many inventions born from a more detailed analysis of the process from bubble generation to defoaming from the viewpoint of forming discharged droplets.
It has reached an extremely high level as compared with the conventional technical level of lowering the printing quality peculiar to an inkjet, reducing the satellite that stains the apparatus itself and the recording medium, and providing the stability of the image quality in the continuous ejection operation.

Further, by controlling the first shot (first dot) by bringing the inside of the nozzle close to the state of ejection in advance,
We have come to the knowledge that the amount of satellite dots can be reduced, satellite dots can be sped up (low-speed satellite dots are reduced), and satellite dot orientation can be controlled. Moreover,
By controlling the first shot (first dot) as described above,
It has been found that the amount of satellite dots in the second shot (second dot) is smaller than that in the first shot.

The main objects of the present invention are as follows.

A first object of the present invention is to suppress the generated bubbles, the liquid on the discharge port side and the liquid on the supply side of the bubbles by the movable member and the structure of the entire liquid flow path, thereby providing a very novel liquid discharge principle. To provide.

A second object of the present invention is to provide a liquid ejecting method and a liquid ejecting head in which the satellite is reduced by suppressing the ejected droplet forming process and the satellite is completely eliminated in the ejecting operation.

A third object of the present invention is to reduce the load structure on the system of the recording apparatus for eliminating the adverse effects due to the fluctuation of satellites and meniscus.

[0020]

To achieve the above object, the present invention provides a heating element for generating thermal energy for generating bubbles in a liquid, and a discharge port for discharging the liquid. A liquid flow path that is in communication with the discharge port and has a bubble generation region for generating bubbles in the liquid, a movable member that is provided in the bubble generation region and is displaced as the bubble grows, and a displacement of the movable member is desired. A liquid discharge head that discharges the liquid from the discharge port by using the energy at the time of bubble generation. Preliminary displacement means for displacing the movable member independently of bubble growth is provided, and the restriction portion is provided so as to face the bubble generation region of the liquid flow path, and the displaced movable member and restriction portion are provided. of By qualitative contact, liquid flow path having the bubble generating area except for the discharge port, characterized in that a substantially closed space.

Further, according to 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, and the bubbles are bubbled in the liquid. A liquid flow path having a bubble generation region to be generated, a movable member provided in the bubble generation region and displaced with the growth of the bubbles, and a restriction portion for restricting displacement of the movable member within a desired range, A liquid ejection method using a liquid ejection head that ejects the liquid from the ejection port by the energy when bubbles are generated, wherein the liquid ejection head further displaces the movable member independently of the growth of the bubbles. And a step of displacing the movable member by the preliminary displacement means before the generation of the bubbles, the movable member being provided on the restriction portion before maximum foaming of the bubbles. Liquid flow path having said bubble generating area Shi erosion is characterized by having a step of a substantially closed space except the discharge port.

Further, in the above-mentioned method, the movable member comes into contact with the regulating portion and receives the stress of the form pulled in the upstream direction due to the movement of the liquid in the upstream direction and the bubble growth, The method further comprises the step of starting the defoaming of.

Further, the method further comprises the step of contracting the bubbles while the movable member is in contact with the regulating portion.

Further, in the step of contracting the bubble while the movable member is in contact with the regulating portion, most of the movement of the liquid due to the contraction of the bubble is directed in the upstream direction from the ejection port, and The meniscus is being pulled into rapidly.

Further, during the bubble shrinking step, the movable member is separated from the regulating portion to generate a liquid flow in the bubble generating region in the downstream direction toward the discharge port, so that the meniscus is rapidly drawn. There is a step of braking.

In the liquid discharge head having the above-mentioned structure, unlike the foaming from the normal steady state, since the movable member is foamed by the preliminary displacement means in the same state as in the continuous discharge, the bubble is grown. In the process, the time lag between the maximum growth of the bubble and the maximum displacement of the movable member is reduced, and the time lag between the bubble contraction and the downward displacement of the movable member due to the contraction is also reduced. That is, the followability of the movable member to the bubbles is improved. In the case of the present invention, the meniscus rapidly pulls in the trailing portion forming a liquid column connected to the ejected droplets with a strong force to make the trailing portion elongated, but as described above, the followability of the movable member to the bubbles is improved. Then, since the rapid pull-in time of the meniscus is shorter than that in the case of foaming from the steady state, the shape of the tailing portion becomes thin only behind the discharged droplet. Therefore, the number of satellite dots left outside the ejection port is extremely reduced.

Other effects of the present invention can be understood from the description of each embodiment.

The terms "upstream" and "downstream" used in the description of the present invention refer to the direction of flow of the liquid from the liquid supply source through the bubble generation region (or movable member) to the discharge port.
Alternatively, it is expressed as an expression regarding this structural direction.

The "downstream side" of the bubble itself means
It means a bubble generated in the downstream side with respect to the center of the bubble in the flow direction or the structural direction, or in the region downstream from the center of the area of the heating element. Similarly, the term "upstream side" regarding the bubble itself means a bubble generated in the upstream side with respect to the flow direction or the above structural direction with respect to the center of the bubble, or in the region upstream from the center of area of the heating element. To do.

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 in the proximity state in which a liquid of several μm is interposed therebetween. Good.

[0031]

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 showing one embodiment of the liquid discharge head of the present invention cut in the liquid flow path direction, and shows characteristic phenomena in the liquid flow path in (a) to (g). 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 applying the heat energy to 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 in the vicinity of the surface where the heating element 2 contacts the discharge liquid. 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 ejection port 18, and is supported by a support portion 33 and a piezo element 34 arranged on the substrate 1 on the upstream side. The piezo element 34 has a movable member 31 on the side opposite to the free end 32 via a fulcrum 33.
Supporting the end of. In particular, in the present embodiment, the free end 32 has the free end 32 in order to suppress the growth of the upstream half of the bubbles, which affects the back wave to the upstream side and the inertial force of the liquid.
It is located near the center of. The movable member 31 can be displaced with respect to the support portion 33 as the bubbles generated in the bubble generation region 11 grow or the piezo element 34 contracts and deforms.

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. 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.

With the above structure, the displaced movable member 31
Due to the contact between the stopper 64 and the stopper 64, the liquid flow path 10 having the bubble generation region 11 becomes a substantially closed space except for the discharge port 18, which is a characteristic head structure that has not been obtained in the past.

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 the movable member 31 is displaced upward by driving the piezo element 34 which is the preliminary displacement means. When the piezo element 34 contracts toward the substrate 1, the movable member 31 is displaced upward with the fulcrum portion 33 as the center by the lever principle. The driving of the piezo element 34 and the displacement of the movable member 31 are slight, and the liquid around the bubble generating region 11 is slightly moved to the upstream side and the downstream side, but the ejection droplets are not ejected from the ejection ports 18.

In FIG. 1C, a part of the liquid filling the bubble generating region 11 is heated by the heating element 2 in the state where the movable member 31 is displaced upward as shown in FIG. 1B. Thus, the bubble 40 accompanying the film boiling has grown to the maximum extent. At this time, the pressure wave based on the generation of the bubbles 40 propagates in the liquid flow path 10, and accordingly, the liquid in the liquid flow path 10 moves to the downstream side and the upstream side with the central region of the bubble generation region as a boundary, and the upstream side. On the side, the movable member 31 is displaced by the flow of liquid accompanying the growth of the bubbles 40, and on the downstream side, the discharge droplet 66 is being discharged from the discharge port 18. Here, in the movement of the liquid toward the upstream side, that is, in the direction of the common liquid chamber 13, the resistance from the flow passage with respect to the movement of the liquid is lower than that on the downstream side, and the liquid is easily flown in the low flow passage. Although a large flow occurs due to the resistance region 65, when the movable member 31 is displaced until it comes close to or comes into contact with the stopper 64, further displacement is restricted, so that the movement of the liquid in the upstream direction is also largely restricted there. 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, some of the bubbles 40, the growth of which is restricted by the movable member 31, pass through a slight gap between the side walls of the liquid flow path 10 and the side portion of the movable member 31, and rise to the upper surface side of the movable member 31. is doing.
This raised bubble is referred to as “raised bubble (41)” in this specification.
Will be called.

In this state, the overall shape of the liquid flow path to the discharge port side with respect to the movable member 31 is such that it widens from the upstream side to the downstream side.

In the present invention, as shown in FIG. 13, between the discharge port side portion of the bubble 40 and the discharge port, there 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 of the heating element having influence on the discharge port side of bubbles ((downstream side) It suffices that the and are directly connected by a straight line. This means that when there is no fluid in the flow path, the heating element, especially the downstream side of the heating element, can be observed when viewed from the outside of the discharge port. It is in a state.

On the other hand, as described above, since the displacement of the movable member 31 is restricted by the stopper 64 in the upstream portion of the bubble 40, the movable member 31 is projected upstream by the inertial force of the liquid flow to the upstream side. It has a small size in a state that it stays until it is bent into shape and charged with stress. As a whole of this portion, the stopper portion, the liquid flow path partition wall 101, the movable member 31, and the fulcrum 33 have almost no amount of entering the upstream region. (However, a partially raised bubble is allowed for a space of 10 μm or less in the gap between the movable member 31 and the liquid flow path partition wall 101.).

As a result, the liquid flow to the upstream side is significantly restricted, and fluid crosstalk to the adjacent nozzles and liquid backflow and pressure oscillation in the supply path system which hinders high-speed refill described later are prevented.

FIG. 1 (d) shows a state in which the negative pressure inside the bubbles overcomes the movement of the liquid to the downstream side in the liquid flow path after the above-mentioned film boiling, and the contraction of the bubbles 40 is started. At this point, since a large force of the liquid in the upstream direction due to bubble growth remains, the movable member 31 is still in contact with the stopper 64 for a certain period after the start of contraction of the bubble 40, and most of the contraction of the bubble 40 occurs. Generates a liquid moving force from the discharge port 18 in the upstream direction. In the state of FIG. 1C, the movable member 31 is in a stress-charged state in which the movable member 31 is curved in a convex shape toward the upstream side. Therefore, in FIG. 1D, as the movable member itself, the stress is released from the upstream side. A force is generated that pulls back the flow and makes a concave shape in the upstream direction. Therefore, from a certain point in time, the pulling force of the movable member from the upstream direction overcomes the above-described moving force of the liquid in the upstream direction, and a slight amount of flow starts from the upstream side to the discharge port side. Also, the bending is reduced, and the displacement to the concave shape starts in the upstream direction. That is, an unbalanced state occurs between the upstream side and the downstream side of the bubble 40, in which a total flow of liquid in the liquid flow path is unidirectionally directed toward the discharge port.

At the timing immediately after that, the movable member 31 and the stopper 64 which are still displaced as a whole in the liquid flow path.
A liquid flow path 1 having a bubble generation region 11 by contact with
Since 0 is a substantially closed space except for the ejection port 18, the contraction energy of the bubble 40 strongly acts as a force for moving the liquid in the vicinity of the ejection port 18 in the upstream direction as a total balance. 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. 1E, the number of droplets, that is, satellites (sub-droplets) 67 left outside the ejection port 18 decreases.

Particularly in this case, unlike the foaming from the normal steady state, the foaming is performed in the state in which the movable member 31 is displaced upward as in the continuous discharge state. The time lag between the maximum growth and the maximum displacement of the movable member is reduced, and the time lag between the contraction of the bubbles and the accompanying downward displacement of the movable member 31 is also reduced. That is, the followability of the movable member to the bubbles is improved. In the case of the present invention, since the meniscus rapidly pulls in the trailing portion which is connected to the discharge droplet 66 and forms a liquid column with a strong force, the trailing portion becomes elongated, but as described above, the ability of the movable member to follow bubbles is reduced. If it improves, the shape of the tailing portion becomes thin only behind the ejected droplet, because the rapid pulling-in time of the meniscus is shorter than that in the case of foaming from the steady state. Therefore, the number of satellite dots left outside the ejection port 18 is extremely reduced.

Here, the state of displacement of the movable member due to foaming and contraction of bubbles will be described with reference to FIG. FIG. 2 is a diagram showing the mutual relationship between the displacement of the movable member, the volume change of the bubbles, and the flow (including liquid and gas) at the discharge port. FIG. 2A is the foaming when the movable member is in the normal state, (B) is a figure which shows foaming in the state where the movable member was displaced upwards.

In FIG. 2 (a), foaming is initiated by rapid heating of the heating element, and it tends to grow large.
Since the movable member has to be pushed up, the movable member begins to be displaced slightly after the growth of the foam. Also, in the defoaming process, since the movable member is still trying to move upward due to inertia, it starts to be displaced downward after the defoaming of the bubbles. On the other hand, in FIG. 2B, by using the preliminary displacement means,
Since foaming is started in a state in which the movable member is displaced upward, unlike the case of FIG.
Less work to push up the movable member. for that reason,
The time lag between maximum foaming and maximum displacement of the movable member is reduced. Further, since the time shift is small, the timing at which the movable member starts to move downward in the defoaming step also becomes earlier, and the time shift of the downward displacement of the movable member with respect to the bubble defoaming becomes smaller.

Subsequently, FIG. 1E shows a state in which the defoaming step is almost completed and the discharged liquid droplet 66 and the meniscus M are separated. In the low flow path resistance region 65, due to the repulsive force of the movable member 31 and the contracting force of the bubble 40 defoaming against the moving force of the liquid in the upstream direction, the downward displacement of the movable member 31 and the accompanying low flow path resistance region 65 are caused. The flow in the downstream direction is started,
The proximity or contact state between the movable member 31 and the stopper 64 starts to open. Along with this, the flow in the downstream direction in the low flow path resistance region 65 has a small flow path resistance, so 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 remains outside the ejection port 18 or is a liquid column portion that is convex toward the ejection port 18. While taking in as little as possible, it starts returning to the position before foaming at a relatively low speed. In particular,
The return flow of the meniscus M and the refill from the upstream merge to form a region where the flow velocity is almost zero between the discharge port 18 and the heater 2, so that the meniscus converges well. Although this depends on the viscosity and surface tension of the ink, according to the present invention, this liquid column separates and becomes a satellite and adheres to the printed matter to deteriorate the image quality, or adheres near the orifice and adversely affects the ejection direction. It is possible to drastically reduce the number of things that cause a discharge failure or cause a discharge failure.

Further, since the meniscus M itself also starts to recover before being largely drawn into the liquid flow path, the meniscus M will recover in a short time even if the liquid moving speed itself is not so large. Exit 1
The amount of the convex shape outward of the discharge port 18 without stopping at 8 is reduced, and the discharge port 1 generated subsequent to the overshoot
It is possible to finish the damped oscillation phenomenon with 8 as the convergence point in an extremely short time. Since this damped vibration phenomenon also adversely affects the printing quality, the present invention enables stable high-speed printing.

The movable member 31 and the stopper 6 described above are also provided.
The flow-in to the liquid flow path 10 through the portion between 4 is shown in FIG.
As shown in (e), since the flow velocity on the wall surface on the side of the top plate 50 is increased, very small bubbles and the like remain at this portion,
Contributes to the stability of ejection.

On the other hand, some satellites 67 existing immediately after the ejected droplet 66 are very close to the ejected droplet due to the rapid meniscus drawing in FIG. A phenomenon called a slipstream phenomenon occurs in which the vortex of air generated in the surface receives a force attracted to the discharged droplet.

This phenomenon will be described in detail. In the conventional liquid ejection head, the droplet does not form a sphere at the moment when the liquid is ejected from the ejection port, and is ejected in a state close to a liquid column having a spherical portion at the tip. It is known that when the trailing portion is pulled by both the main droplet and the meniscus and separated from the meniscus, satellite dots are formed from the trailing portion and fly to the recording medium together with the main droplet. . Since the satellite dots fly after the main droplet, the ejection speed is low because the satellite dot is pulled by the meniscus, and the landing position of the satellite dot deviates from the main droplet, deteriorating the print quality. In the liquid ejection head according to the present invention,
As described above, since the force for retracting the meniscus is larger than that of the conventional liquid ejection head, the force for pulling the tailing portion after the main droplet is ejected is strong, and the force for separating the tailing portion and the meniscus becomes strong, and this separation is performed. The timing will be earlier. Therefore, the satellite dots formed from the trailing portion become smaller, and the distance between the main droplet and the satellite dot becomes shorter. Furthermore, since the trailing portion does not continue to be pulled by the meniscus, the ejection speed does not decrease, and the satellite 67 is attracted by the so-called slipstream phenomenon behind the ejection droplet 66.

FIG. 1F shows a further advanced state of FIG. 1E. The satellite 67 has a further drop 66.
And are attracted at the same time, and the pulling force due to the slipstream phenomenon also increases. On the other hand, from the upstream side, the discharge port 18
The liquid is moved in the direction in which the liquid 40 is drawn downward from the initial position by the completion of the defoaming process of the bubbles 40 and the displacement overshoot of the movable member 31 to draw the liquid from the upstream side and the discharge port 18.
This causes the phenomenon of the liquid being pushed in the direction. In addition, the cross-sectional area of the liquid flow path in which the stopper 64 is present is increased to increase the liquid flow in the direction of the discharge port 18 and accelerate the return of the meniscus M to the discharge port 18. As a result, the refill characteristics in this embodiment are dramatically improved.

Further, when cavitation occurs when bubbles disappear, the defoaming point and the discharge port 18 are separated by the downward displacement of the movable member 31, so that the shock wave due to cavitation is not directly transmitted to the discharge port 18 and the movable member 31. Since a large amount of light is absorbed by the cavitation, shock waves due to cavitation reach the meniscus, and minute droplets called microdots are hardly generated from the meniscus, but
The phenomenon that the microdots adhere to the printed matter to deteriorate the image quality, or the microdots adhere to the vicinity of the ejection port 18 to make the ejection unstable is drastically reduced.

Further, since the cavitation generation point due to defoaming is also shifted to the fulcrum 33 side by the movable member 31, the damage to the heater 2 is reduced. Further, the viscous ink is forcibly moved between the movable member 31 and the heater 2 and removed from this closed region, so that the ejection durability is improved. At the same time, due to the same phenomenon, the amount of burnt deposits on the heater in this region is reduced, and the ejection stability is improved.

FIG. 1 (g) shows a state in which the state of FIG. 1 (f) has further advanced and the satellite 67 has been taken into the ejected droplet 66. The combination of the discharge droplet 66 and the satellite 67 does not always occur in each discharge even in the other embodiments.
It may or may not occur 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 due to 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. 12 is a see-through perspective view of a part of the head shown in FIG. 1 (b), which basically shows the same state as that shown in FIG. 1 (b) 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. Furthermore, in the step of growing foam by the heating element 2,
The bubble 40 displaces the movable member 31, rises to the upper surface side of the movable member 31 through the clearance, and slightly enters the low flow path resistance region 65. The intruding raised bubbles 41 wrap around the back surface of the movable member 31 (the surface opposite to the bubble generation area 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.

<Preliminary Displacement Means for Movable Member> FIG.
FIG. 9A is a cross-sectional view in the flow path direction showing a modified example of the preliminary displacement means of the movable member of the liquid ejection head shown in FIG. FIG. 6B is a diagram showing an example in which an electrode is provided on the upper surface of the nozzle and the movable member is displaced by an electrostatic force.

As shown in FIG. 3A, as a pre-displacement means for displacing the movable member 31 upward before foaming, it is provided near the fulcrum 33 of the movable member 31 of the element substrate 1 for discharging. A small heating element 3 having a smaller area than the heating element 2 for foaming the liquid is installed. By growing bubbles on the small heating element 3 by the heat generation of the small heating element 3, the movable member 31 can be displaced upward with the fulcrum portion 33 as a fulcrum.

As another example, as shown in FIG. 3B, the electrode 4 is provided on the wall surface of the flow path including the stopper 64 for restricting the displacement of the movable member 31, and the electrode 4 and the movable member 31 are provided.
A voltage can be applied between and. Thereby, when a voltage is applied between the electrode 4 and the movable member 31, the movable member 31 is attracted to the electrode 4 by electrostatic force and is displaced upward with the fulcrum portion 33 as a fulcrum.

<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, highly durable silver, nickel, gold, iron, titanium, aluminum,
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,
The flow of the liquid at the time of foaming by the heating element can be properly controlled and effectively used.

By applying 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 the 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 utilize 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 which effectively acts on the movable member.
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 distinguishing between the step of acting and the step of acting comprehensively, it is extremely important to arrange the movable member so that only the upstream side portion from the central region faces the movable member, I can say. In this embodiment,
Although the effective foaming area is set to be approximately 4 μm or more inside from the periphery of the heating element, it is not limited to this depending on the type of the heating element and the forming method.

Further, in order to favorably form the above-mentioned substantially closed space, it is preferable that the distance between the movable member and the heating element in the standby state is 10 μm or less.

<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 shows a liquid ejecting head having no 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 very 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. 6B. 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 heating element, only the 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 ejected liquid are generated. 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 heating portion 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 used for recording (recording liquid), the ink having the composition used in the conventional bubble jet device can be used.

Further, it is possible to use even a liquid having a low foaming property or a high viscosity liquid which has been difficult to be ejected conventionally.

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 discharge liquid. However, since the discharge speed of the ink increased due to the improvement of the discharge force, the liquid The landing accuracy of the drops is improved, and a very good recorded image can be obtained.

[0090] 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 Discharge Head> FIG. 8 is an exploded perspective view showing the overall structure of the liquid discharge 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. The movable member 31 is supported on this 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. 2 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 in 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. The movable members 31 have 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 action 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 grow to the maximum. 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 in contact with the stopper 64, Most of the contraction of 40 is the discharge port 18
Liquid is caused to flow in the upstream direction. Therefore, the meniscus is largely drawn from the ejection port 18 into the liquid flow path 10 at this point, and the liquid column connected to the ejection droplet 66 is quickly separated with a strong force. As a result, the amount of droplets, that is, satellites, left behind on the outside of the ejection port 18 is reduced.

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 refill 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 are moved from the low flow path resistance regions 65 to the bubble generation regions 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. 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 a 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 ink discharge recording in the liquid discharge method and liquid discharge head of the present invention.

The recording apparatus 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 applicable 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, etc., 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.

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. 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.

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

[0111]

According to the valve mechanism of the movable member of the liquid discharge head according to the present invention, the liquid is prevented from moving in the upstream direction due to the back wave, that is, the pressure wave in the upstream direction, and at the same time, the liquid flows through the liquid flow path. You can improve the refill by reducing the resistance received from. Also, while suppressing the inertial force in the direction opposite to the liquid supply direction due to the back wave, the meniscus is rapidly drawn into the ejection port, and the rapid meniscus pull-in is braked before the meniscus receding amount increases, It is possible to prevent satellite dots, increase the refill frequency, and improve the printing speed. Furthermore, by suppressing the vibration of the meniscus, the ejection can be stabilized and the printing quality can be improved. Further, when the valve mechanism operates due to the generation of bubbles, the resistance received from the liquid flow path to the predetermined displacement position of the movable member is reduced, and the proper displacement position of the movable member is quickly reached to improve the discharge efficiency. .

In particular, according to the present invention, according to the structure for quick separation of the meniscus from the trailing portion which forms the liquid column by being connected to the discharged droplet and the rapid convergence of the meniscus vibration, It is possible to achieve responsiveness and stabilization of droplet formation and enable high-speed recording or high-quality recording by high-speed liquid ejection.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a mutual relationship between displacement of a movable member, volume change of bubbles, and flow (including liquid and gas) at a discharge port.

FIG. 3 is a cross-sectional view in the flow path direction showing a modified example of the preliminary displacement means of the movable member of the liquid ejection head shown in FIG.

4 shows 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.

FIG. 12 is a perspective view of a part of the head shown in FIG. 1 (b).

FIG. 13 is a sectional view of a flow path for explaining a “linear communication state” of the liquid ejection head of the present invention.

[Explanation of symbols]

1 element substrate 2 heating element 3 small heating elements 10 liquid flow paths 11 Bubble generation area 13 Common liquid chamber 18 outlets 31 Movable member 32 Free end 33 fulcrum 34 Piezo element 40 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 Hiroyuki Ishinaga             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 AF06 AF09 AF28 AF52 AG12                       AG46 AG76 AJ03 AJ04 BA03                       BA04 BA13

Claims (18)

[Claims] 1. A heating element that generates thermal energy for generating bubbles in a liquid, a discharge port that discharges the liquid, and a bubble that communicates with the discharge port and generates bubbles in the liquid. A liquid flow path having a generation area, a movable member that is provided in the bubble generation area and is displaced as the bubble grows, a restricting portion that restricts displacement of the movable member within a desired range, the heating element and the movable member. A substrate having a member, the liquid discharge head discharging the liquid from the discharge port by using the energy at the time of generating the bubble, the preliminary displacement of the movable member independently of the growth of the bubble. A liquid having a bubble generation region by means of substantial contact between the displaced movable member and the regulation unit, wherein the regulation unit is provided so as to face the bubble generation region of the liquid flow path. Road with the exception of the discharge port, a liquid discharge head characterized by comprising a substantially closed space. 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 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. 5. The liquid ejection head according to claim 3, wherein the movable member is brought into contact with the restriction portion near the free end. 6. The liquid ejection head according to claim 1, wherein the restriction portion is formed by partially reducing a distance of the liquid flow path from the movable member. 7. The liquid ejection head according to claim 1, wherein the ejection port is provided above the heating element. 8. A plurality of the movable members are formed for one heating element, and the plurality of movable members are formed so as to be symmetrical with respect to a foaming center of the heating element. The liquid ejection head according to claim 7. 9. The liquid according to claim 1, wherein the preliminary displacement means is a heating element formed on an upstream side of a supporting portion of the movable member to the substrate with respect to a liquid supply direction. Discharge head. 10. The liquid according to claim 1, wherein the pre-displacement means is a piezo element formed on an upstream side in a liquid supply direction with respect to a supporting portion of the movable member to the substrate. Discharge head. 11. The liquid discharge head according to claim 1, wherein the heating element and the discharge port are in a linear communication state. 12. A heating element that generates thermal energy for generating bubbles in a liquid, a discharge port that discharges the liquid, and a bubble that communicates with the discharge port and generates bubbles in the liquid. A liquid flow path having a 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. Is a liquid ejection method using a liquid ejection head that ejects the liquid from the ejection port by the energy of the preparatory displacement means for displacing the movable member independently of the growth of the bubbles. And a step of displacing the movable member by the preliminary displacement means before the generation of the bubbles, the movable member comes into contact with the restriction portion before maximum foaming of the bubbles, and A method for ejecting liquid, comprising a step of forming a liquid flow path having a bubble generation region into a space which is substantially closed except for the ejection port. 13. A step of starting defoaming of the bubbles after the movable member is brought into contact with the restriction part and receives a stress of a form pulled by movement of the liquid in the upstream direction and bubble growth. 13. The method according to claim 12, further comprising:
The method for ejecting a liquid according to. 14. The liquid ejection method according to claim 12, further comprising a step of contracting the bubbles while the movable member is in contact with the restriction portion. 15. In the step of contracting the bubble while the movable member is in contact with the restriction portion, most of the movement of the liquid due to the contraction of the bubble is directed in the upstream direction from the ejection port, The liquid ejecting method according to claim 14, wherein the meniscus is rapidly drawn into. 16. During the bubble shrinking step, the movable member is separated from the regulating portion to generate a liquid flow in a downstream direction toward the discharge port in the bubble generating region, and the meniscus is suddenly braked. The liquid discharging method according to claim 15, wherein 17. A liquid ejecting head according to claim 1, and a recording medium conveying unit that conveys a recording medium that receives the liquid ejected from the liquid ejecting head. Liquid ejector. 18. The liquid ejection apparatus according to claim 17, wherein recording is performed by ejecting ink from the liquid ejection head and adhering the ink to the recording medium.