JP2001225471A - Liquid ejection head and liquid ejector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance liquid ejection efficiency by suppressing backward liquid flow effectively in the initial bubbling stage. SOLUTION: A liquid channel 3 having a bubble generating region 11 and communicating, at one end thereof, with an ejection opening 7 is formed between an element substrate 1 and a top plate 2. The liquid channel 3 is provided with a supply part forming member 5A having a liquid supply opening 5 communicating with a common liquid supply chamber 6, and a cantilever movable member 8 disposed oppositely to the liquid supply opening 5. The movable member 8 is supported while spaced apart from the supply part forming member 5A. A protrusion 5B is formed on the lower surface of the supply part forming member 5A oppositely to the free end of the movable member 8 and a channel communicating with the liquid channel 3 from the liquid supply opening 5 at the free end of the movable member 8 is bent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid discharge head for discharging liquid by applying thermal energy to liquid to generate bubbles, and a liquid discharge apparatus using the liquid discharge head.

[0002] The present invention also relates to a facsimile having a printer, a copier, a communication system, and a printer for performing recording on a recording medium such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics and the like. The present invention can be applied to a device such as a word processor having a unit, and further to an industrial recording device combined with various processing devices.

In the present invention, "recording" means not only giving an image having a meaning such as a character or a figure to a recording medium, but also giving an image having no meaning such as a pattern. Is also meant.

[0004]

2. Description of the Related Art Conventionally, in a recording apparatus such as a printer, ink such as heat is applied to a liquid ink in a flow path to generate bubbles, and ink is ejected from an ejection port by an action force based on a steep volume change accompanying the energy. An ink jet recording method for forming an image by attaching the ink to a recording medium, that is, a so-called bubble jet recording method, is known. As disclosed in U.S. Pat. No. 4,723,129 and the like, a recording apparatus using this bubble jet recording method includes a discharge port for discharging ink, a flow path communicating with the discharge port, An electrothermal converter is generally provided as an energy generating means for discharging ink arranged in the flow path.

According to such a recording method, a high-quality image can be recorded at high speed and with low noise, and in a head performing this recording method, ejection ports for ejecting ink are arranged at a high density. Therefore, it has many advantages that a high-resolution recorded image and a color image can be easily obtained with a small device. For this reason, this bubble jet recording method has recently been used in many office devices such as printers, copiers, and facsimile machines, and has also been used in industrial systems such as textile printing devices.

As described above, various demands are increasing as the bubble jet technology is used for products in various fields.
For example, in order to obtain a high-quality image, a drive condition for providing a liquid discharge method or the like in which the ink discharge speed is high and a good ink discharge based on stable bubble generation is proposed. From the viewpoint, there has been proposed an improved channel shape in order to obtain a liquid ejection head having a high filling (refilling) speed of the ejected liquid into the liquid channel.

Among them, in a head which generates bubbles in a nozzle and discharges liquid as the bubbles grow, the growth of bubbles in the direction opposite to the discharge port and the resulting liquid flow deteriorates discharge energy efficiency and refill characteristics. It is known as a factor that causes such problems, and an invention of a structure that improves such discharge energy efficiency and refill characteristics is proposed in European Patent Application Publication No. EP0436047A1.

The invention described in this publication discloses a first valve for shutting off the air between the vicinity of the discharge port and the bubble generating section and a first valve for completely shutting off the air between the bubble generating section and the ink supply section. The two valves are alternately opened and closed (EP 43604).
7A1 FIGS. 4 to 9). For example, in the example of FIG.
As shown in FIG. 24, a heating element 110 is provided substantially at the center of the ink flow path 112 between the ink tank 116 and the nozzle 115 on the substrate 125 forming the inner wall of the ink flow path 112. The heating element 110 is provided inside the ink flow path 112.
It is in a compartment 120 that is completely closed. Ink channel 11
2 is a substrate 125, thin films 123 and 126 directly laminated on the substrate 125, and tongues 113 and 13 as closing bodies.
0. The open tongue is shown in broken lines in FIG. Another thin film 123 extending in a plane parallel to the substrate 125 and terminating at the stopper 124 shields the ink flow path 112. When bubbles form in the ink, the free end of the tongue 130 in the nozzle area, which is stationary and in close contact with the stopper 126, is displaced upwards and the ink liquid flows from the compartment 120 into the ink flow path 112. It is injected into and then through nozzle 115. At this time, since the tongue-shaped piece 113 provided in the area of the ink tank 116 is in close contact with the stopper 124 in a stationary state,
The ink liquid in 0 does not go to the ink layer 116.
When the bubbles in the ink disappear, the tongue 130 is displaced downward and comes into close contact with the stopper 126 again. Then, the tongue 113 falls down into the ink compartment 120, whereby the ink liquid flows into the compartment 120.

[0009]

[0005] However, EP0436047
In the invention described in A1, since the three areas of the area near the ejection port, the bubble generation section, and the ink supply section are divided into two, the ink that follows the droplet at the time of ejection becomes a large tail, The number of satellite dots becomes considerably larger than that of a normal ejection method in which growth, shrinkage, and defoaming are performed (the effect of meniscus receding due to defoaming is presumed to be unusable). Also, the valve on the side of the bubble discharge port causes a large loss of discharge energy. Further, at the time of refilling (when refilling the nozzles with ink), the liquid is supplied to the bubble generating portion along with the defoaming. However, the liquid cannot be supplied to the vicinity of the discharge port until the next bubble is generated. Not only is the dispersion of the droplets large, but the ejection response frequency is extremely low, which is not practical.

The present invention provides an epoch-making method and head structure for improving the efficiency of suppressing the bubble growth component in the direction opposite to the discharge port and satisfying the contradictory high efficiency of the refill characteristic. The present invention proposes an invention that also satisfies the improvement of the discharge efficiency based on a new idea to find out.

As a result of intensive studies, the present inventors have found that a special check valve function is provided in a nozzle structure of a liquid discharge head that generates bubbles in a linearly formed nozzle and discharges liquid as the bubbles grow. As a result, it was found that bubble growth in the opposite direction (rearward) to the discharge port was suppressed, and that the rearward discharge energy could be effectively used on the discharge port side. In addition, it has been found that the discharge response frequency can be extremely increased by suppressing the backward bubble growth component by a special check valve function.

That is, an object of the present invention is to simultaneously improve a discharge power and a discharge frequency by using a nozzle structure and a discharge method using a novel valve function, thereby achieving a high-speed and high-definition image at a level that could not be achieved conventionally. It is to establish a new ejection method (structure) for achieving a head. In particular,
An object of the present invention is to improve the airtightness by the above-described check valve and effectively suppress the backward flow of the liquid in the initial stage of foaming, thereby improving the liquid discharge efficiency.

[0013]

The liquid discharge head of the present invention obtained in the above-described research process has a discharge port for discharging a liquid, and a bubble formed in the liquid, one end of which is always in communication with the discharge port. A liquid flow path having a bubble generation area for generating a liquid supply port, and a liquid supply port opened to the liquid flow path for communicating the liquid flow path with a liquid supply chamber holding a liquid to be supplied to the liquid flow path, An area surrounded by at least the free end and both sides continuous with the liquid flow path, which is disposed to face the liquid supply port with a gap therebetween and is supported with one end of the liquid flow path as a free end. A movable member that is larger than an opening area of the liquid supply port with respect to the liquid flow path, and a flow path from the liquid supply port formed by the gap to the liquid flow path is bent at a free end of the movable member. Is characterized by

Such a bent flow path can be obtained by having a protruding portion at a position of the liquid flow path opposite to the free end of the movable member via a gap. Further, the discharge port and the bubble generation region may be in a linear communication state.

Preferably, in the liquid discharge head according to the present invention, the liquid supply port is substantially blocked by the movable member during a period in which the entire bubble generated in the bubble generation region is growing substantially isotropically. Thereafter, during a period in which the portion of the bubble on the discharge port side of the bubble grows and the portion on the movable member side contracts, the movable member is displaced to the bubble generation region side, and the liquid supply chamber is set through the liquid supply port. From the liquid flow path to the liquid flow path, or the free end of the movable member is displaced toward the liquid supply port side at the initial stage of the generation of bubbles, and the liquid supply port is substantially shut off from the liquid flow path. At the same time as the defoaming, the free end of the movable member is displaced toward the bubble generation region, and liquid can be supplied from the liquid supply chamber to the liquid flow path through the liquid supply port.

A liquid discharge apparatus according to the present invention includes the above-described liquid discharge head according to the present invention, and transport means for transporting a recording medium that receives liquid discharged from the liquid discharge head. The recording is performed by discharging ink from the liquid discharge head and attaching the ink to a recording medium.

In the structure described above, when a bubble is generated in the bubble generation region, the liquid flow path and the liquid supply port are substantially sealed immediately by the movable member at the initial stage. Therefore, the pressure wave due to the bubble growth in the bubble generation region is not propagated to the liquid supply port side and the liquid supply chamber side, and most of the pressure wave is directed to the discharge port side, so that the discharge power is dramatically improved. In addition, even if high-viscosity recording liquid is used in order to fix onto recording paper at high speed or eliminate bleeding at the boundary between black and color, it is possible to discharge satisfactorily by dramatically improving the discharge power. Can be. In addition, when the environment changes during printing, especially in a low-temperature, low-humidity environment, the ink thickening area increases at the ejection port, and the ink may not be ejected normally at the start of use. . Also, since the discharge power has been dramatically improved, the size of the heating element used as the bubble generating means has been reduced,
The energy input for ejection can also be reduced.

In addition, since the flow path from the liquid supply port to the liquid flow path is bent at the free end of the movable member, the flow of the liquid from the liquid flow path to the liquid supply port in the initial stage of foaming is suppressed. Thereby, the substantially closed state between the liquid flow path and the liquid supply port by the movable member is reliably created, so that the ejection characteristics are further improved. In addition, since the flow of the liquid from the liquid flow path to the liquid supply port is suppressed, the amount of meniscus retreat at the discharge port after the droplet discharge can be minimized. As a result, the time required for the meniscus to return to the initial state after the discharge is very short, that is, the time required to complete the replenishment (refill) of the ink in the liquid flow path is short, so that the ink discharge with high precision (quantity) can be performed. In the implementation, the ejection frequency (drive frequency) can also be dramatically improved.

Further, since the bubble growth in the bubble generation region grows greatly on the discharge port side and the growth on the liquid supply port side is suppressed, the defoaming point changes from near the center of the bubble generation region to the discharge port side. And the defoaming force can be reduced while maintaining the foaming power, so that the mechanical and physical destruction life of the heating element due to the defoaming force in the bubble generation region can be greatly improved.

The 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 flow direction of the liquid from the liquid supply source to the discharge port via the bubble generation region (or movable member).
Alternatively, it is expressed as an expression regarding this structural direction.

The “downstream side” of the bubble itself is
With respect to the center of the bubble, it means a bubble that is generated on the downstream side in the flow direction or the configuration direction, or on the downstream side of the area center of the heating element.

[0023]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the liquid discharge head according to the embodiment along one liquid flow direction, FIG. 2 is a cross-sectional view taken along line XX ′ of FIG.
FIG. 3 is a sectional view taken along the line YY ′ shifted from the center of the discharge port in FIG.

In the liquid discharge head of the multiple liquid path-common liquid chamber type shown in FIGS. 1 to 3, the element substrate 1 and the top plate 2 are fixed in a laminated state via the liquid path side wall 10, 2, a liquid flow path 3 having one end communicating with the discharge port 7 and the other end closed.
Are formed. The liquid flow paths 3 are provided in large numbers in one head. In addition, each liquid flow path 3 is provided in the element substrate 1.
On the other hand, a heating element 4 such as an electrothermal conversion element as a bubble generating means for generating bubbles in the liquid replenished in the liquid flow path 3 is provided. In a region near the surface where the heating element 4 is in contact with the ejection liquid, there is a bubble generation area 11 in which the heating element 4 is rapidly heated and the ejection liquid foams.

A liquid supply port 5 formed in the supply section forming member 5A is provided in each of the plurality of liquid flow paths 3, and a large-capacity common liquid supply chamber 6 communicating with each liquid supply port 5 at the same time is provided. Have been. That is, the common liquid supply chamber 6 is branched from the single common liquid supply chamber 6 into a large number of liquid flow paths 3. An amount of liquid corresponding to the liquid discharged from the discharge port 7 communicating with each liquid flow path 3 is supplied to the common liquid supply chamber 6. Received from liquid supply chamber 6.

A movable member 8 larger than the opening area S of the liquid supply port 5 is provided substantially parallel to the opening area S of the liquid supply port 5 between the liquid supply port 5 and the liquid flow path 3. ing. On the lower surface (the surface facing the movable member 8) of the supply portion forming member 5A, a convex portion 5B facing the free end of the movable member 8 is formed. There is a minute gap between the free end of the movable member 8 and both side ends continuous with it and the supply section forming member 5, and the size of the gap is, as shown in FIGS.
Α (for example, 10 μm or less) between the periphery of the liquid supply port 5, that is, between the upper surface of the movable member 8 and the lower surface of the supply portion forming member 5;
Between the free end of the movable member 8 and the projection 5B, and
Between both side edges of the supply member 5A and the side wall of the supply portion forming member 5A. These gaps allow the liquid supply port 5 to reach the liquid flow path 3
Although a flow path leading to the flow path is formed, the flow path is bent because the projection 5B is formed on the supply section forming member 5A.

As shown in FIG. 2, there is also a minute gap β between the side of the movable member 8 and the side walls 10 on both sides.

The gaps β and γ differ depending on the pitch of the flow path. If the gap γ is large, the movable member 8 easily blocks the opening area S, and if the gap β is large, the movable member 8 is located via the gap α. It is easier to move toward the element substrate 1 with defoaming than in the steady state. In the present embodiment, the gap α is 3 μm,
The gap β was 3 μm, and the gap γ was 4 μm. In addition, the movable member 8 has the opening area S in the width direction between the flow path side walls 10.
Has a width W1 larger than the width W2 of the opening region S.
Has a width that can sufficiently seal the space. 8A of movable member 8
Defines the upstream end of the opening region S of the liquid supply port 5 on an extension of the free end side of the continuous portion in which the plurality of movable members are continuous in the direction intersecting the plurality of liquid paths (FIG. 3). In the present embodiment, as shown in FIGS. 2 and 3, the thickness of a portion of the supply portion forming member 5A along the movable member 8 is set to be smaller than the thickness of the liquid channel side wall 10 itself. The supply section forming member 5A is stacked on the wall 10. In addition, the discharge port 7 side of the supply section forming member 5A from the free end 8B of the movable member 8 is set to have the same thickness as the thickness of the liquid channel side wall 10 itself as shown in FIG. As described above, the movable member 8 can move in the liquid flow path 3 without frictional resistance, while the displacement toward the opening area S is
Can be regulated in the surrounding area. Thereby, while it is possible to substantially close the opening area S and prevent the liquid flow from the inside of the liquid flow path 3 to the common liquid supply chamber 6, with the defoaming of the bubbles,
It becomes possible to move from the substantially closed state to the refillable state toward the liquid flow path side. In the present embodiment, the movable member 8 is also positioned parallel to the element substrate 1. The free end 8B of the movable member 8 is located on the heating element 4 side of the element substrate 1, and the other end is supported by the fixed member 9. Further, the end opposite to the discharge port 7 of the liquid flow path 3 is closed by the fixing member 9.

The opening area S is a substantial area for supplying the liquid from the liquid supply port 5 to the liquid flow path 3.
In the present embodiment, as shown in FIGS. 1 and 3, this is a region surrounded by three sides of the liquid supply port 5 and an end 9 </ b> A of the solid member 9.

Further, as shown in FIG. 4, in the present embodiment, there is no obstacle such as a valve between the heating element 4 as an electrothermal conversion element and the discharge port 7, and the liquid flow is linear. It is in a “linear communication state” that maintains a simple flow path structure. This is more preferably achieved by linearly matching the direction of propagation of the pressure wave generated at the time of the generation of the bubble with the direction of flow of the liquid and the direction of ejection, so that the ejection state of the ejected droplets and the ejection speed are adjusted. It is desirable to create an ideal state of stabilization at a very high level. In the present invention, as one definition for achieving or approximating this ideal state, the discharge port 7 and the heating element 4, particularly, the discharge port side (downstream side) of the heating element having an influence on the discharge port side of the bubble. May be directly connected by a straight line. This is a state in which the heating element, particularly the downstream side of the heating element, can be observed from the outside of the discharge port if there is no fluid in the flow path. (See FIG. 4).

Next, the discharge operation of the liquid discharge head of this embodiment will be described in detail. 5 to 7 are FIGS.
In order to explain the discharge operation of the liquid discharge head having the structure shown in FIG. 5, the liquid discharge head is shown in a cutaway view along the liquid flow path direction, and characteristic phenomena are divided into six steps shown in FIGS. It is shown. Further, in FIGS. 5 to 7, the symbol M represents a meniscus formed by the ejection liquid.

FIG. 5A shows a state before energy such as electric energy is applied to the heating element 4 and before the heating element 4 generates heat. In this state, there is a small gap (10 μm or less) between the free end of the movable member 8 and both side ends continuous with the movable member 8 and the supply portion forming member 5A.

FIG. 5B shows a state in which part of the liquid filling the liquid flow path 3 is heated by the heating element 4, film boiling occurs on the heating element 4, and bubbles 21 grow isotropically. Here, "isotropic bubble growth" refers to a state where the bubble growth rates in the direction perpendicular to the bubble surface are almost equal at various places on the bubble surface.

In the isotropic growth process of the bubble 21 at the initial stage of the bubble generation, the movable member 8 is in close contact with the peripheral portion of the liquid supply port 5 to close the liquid supply port 5, and the inside of the liquid flow path 3 is discharged. Except for the outlet 7, it is substantially closed. At this time, the maximum displacement of the free end of the movable member 8 toward the liquid supply port 5 is represented by h1.
And

FIG. 6A shows a state where the bubbles 21 continue to grow. In this state, since the inside of the liquid flow path 3 is substantially closed except for the discharge port 7 as described above, the liquid does not flow to the liquid supply port 5 side. Therefore, the bubble can largely spread to the discharge port 7 side, but does not spread much to the liquid supply port 5 side. Then, while the bubble growth continues on the ejection port 7 side of the bubble generation region 11, the bubble growth stops on the liquid supply port 5 side of the bubble generation region 11. That is, the bubble growth stopped state is the maximum bubbled state on the liquid supply port 5 side of the bubble generation region 11. The foaming volume at this time is defined as Vr.

Here, FIGS. 5A and 5B and FIG.
The growth process of the bubble 21 in (a) will be described in detail with reference to FIG. When the heating element 4 is heated as shown in FIG. 8A, an initial boiling occurs on the heating element 4 and thereafter, as shown in FIG. Changes to 8 (b) to 8 (c).
As shown in (1), the cells continue to grow isotropically (the state where the bubbles grow isotropically is called a semi-Purrow state). However, as shown in FIG. 5 (b), when the inside of the liquid flow path 3 is substantially closed except for the discharge port 7, the liquid cannot move to the upstream side. Some of the bubbles on the side (liquid supply port side) cannot grow much, and the remaining downstream (discharge port side) part grows greatly. FIGS. 6A, 8D, and 8E show this state.

Here, for convenience of explanation, when the heating element 4 is being heated, a region where the bubble 21 does not grow on the heating member 4 is defined as a region B, and a region on the discharge port 7 side where the bubble 21 grows is defined as an region A. I do. In the area B shown in FIG.
The foam volume is the maximum, and the foam volume at this time is V
r.

Next, FIG. 6B shows a state in which bubble growth continues in the region A and bubble contraction starts in the region B. In this state, in the region A, the bubbles 21 grow greatly toward the ejection port side. Then, the volume of the bubble 21 in the region B starts to decrease. Thereby, the movable member 8
Of the bubble 21 starts to be displaced downward to the steady state position by the restoring force due to its rigidity and the defoaming force of the bubble 21 in the B region. As described above, since the flow path from the liquid supply port 5 to the liquid flow path 3 at the free end of the movable member 8 is bent, the flow path from the liquid supply port 5 to the liquid flow path 3 is changed as shown in FIG. Since the flow of the liquid toward the heating element 4 occurs as indicated by the arrow in (), the downward displacement of the movable member 8 is promoted. As a result, the liquid supply port 5 is opened, and the common liquid supply chamber 6 and the liquid flow path 3 are in communication.

FIG. 7A shows a state in which the bubble 21 has grown to a maximum. In this state, the bubbles 2
1 grows to the maximum, and accompanying this, bubbles 2 in region B
1 is almost gone. The maximum bubble volume in the region A at this time is defined as Vf. Further, the ejection droplet 22 ejecting from the ejection port 7 is still connected to the meniscus M in a long tail state.

FIG. 7B shows a stage in which the growth of the bubbles 21 stops and only the defoaming step is performed.
Indicates a state of being divided. Immediately after changing from bubble growth to bubble elimination in the region A, the contraction energy of the bubbles 21 acts as a force for moving the liquid in the vicinity of the discharge port 7 in the upstream direction as an overall balance. Accordingly, the meniscus M is drawn into the liquid flow path 3 from the discharge port 7 at this time, and the liquid column connected to the discharge droplet 22 is quickly separated with a strong force. On the other hand, with the contraction of the bubbles 21, the liquid rapidly flows into the liquid flow path 3 from the common liquid supply chamber 6 via the liquid supply port 5 as a large flow. As a result, the flow of drawing the meniscus M into the liquid flow path 3 rapidly drops, and the meniscus M starts to return to the position before foaming at a relatively low speed. Therefore, the movable member 8 according to the present invention is provided. The convergence of the vibration of the meniscus M is very good as compared with the liquid ejection method without the above. The amount at which the free end of the movable member 8 is maximally displaced toward the bubble generation region 11 at this time is defined as h2.

Finally, when the bubble 21 completely disappears, the movable member 8 also returns to the steady state position shown in FIG. In this state, the movable member 8 is displaced upward by its elastic force (in the direction of the solid arrow in FIG. 7B). In this state, the meniscus M has already returned near the discharge port 7.

Next, the correlation between the time change of the bubble volume in the region A and the region B in FIGS. 5 to 7 and the behavior of the movable member will be described with reference to FIG. FIG. 9 is a graph showing the correlation. Curve A shows the time change of the bubble volume in the A region, and curve B shows the time change of the bubble volume in the B region.

As shown in FIG. 9, the change over time in the growth volume of bubbles in the region A draws a parabola having a maximum value. That is,
From the start of foaming to the defoaming, the bubble volume increases with time, reaches a maximum at some point, and then decreases. On the other hand, in the region B, the time required from the start of foaming to the defoaming is shorter than that in the region A, the maximum growth volume of the bubble is small, and the time to reach the maximum growth volume is short. That is, in the A region and the B region, the time required from the start of foaming to the defoaming and the change in the growth volume of the bubbles are greatly different, and the B region is smaller.

In particular, in FIG. 9, since the bubble volume increases at the same time change in the initial stage of bubble generation, the curves A and B overlap. That is, in the initial stage of the generation of the bubble, a period in which the bubble is growing isotropically (semi-Purro-like) occurs. After that, although the curve A draws a curve that increases to the maximum point,
At some point, Curve B branches off from Curve A and depicts a curve in which the bubble volume decreases. That is, while the volume of the bubble increases in the region A, a period in which the volume of the bubble decreases in the region B (a partial growth partial contraction period) occurs.

Based on the above-described bubble growth method, when the free end of the movable member 8 covers a part of the heating element 4 as shown in FIG. 1, the movable member 8 behaves as follows. Is generated. That is, the movable member 8 is displaced upward toward the liquid supply port 5 during the period of FIG. In the period shown in FIG. 3, the movable member 8 is in close contact with the liquid supply port 5, and the inside of the liquid flow path 3 is substantially closed except for the discharge port 7. The start of the closed state is performed during a period when the bubbles are growing isotropically. Next, during the period shown in the figure, the movable member 8 is displaced downward toward the steady state position. The opening of the liquid supply port 5 by the movable member 8 is started after a lapse of a fixed time from the start of the partial growth partial contraction period. Next, in the period of FIG. 6, the movable member 8 is further displaced downward from the steady state. Next, during the period shown in FIG. 3, the downward displacement of the movable member 8 is substantially stopped, and the movable member 8 is in an equilibrium state at the open position. Finally, during the period shown in the figure, the movable member 8 is displaced upward toward the steady state position.

The correlation between the bubble growth and the behavior of the movable member 8 is affected by the relative position between the movable member 8 and the heating element 4. Therefore, with reference to FIG. 10 and FIG. 11, a correlation between bubble growth and behavior of the movable member in a liquid ejection head having a movable member and a heating element at a different relative position from the present embodiment will be described.

FIG. 10 shows the bubble growth and the movable member 8 in the form in which the entire upper portion of the heating element 4 is covered by the free end of the movable member 8.
FIGS. 4A and 4B are diagrams for explaining the correlation with the behavior of FIG. 3A, wherein FIG. 3A shows the form and FIG. 3B shows a graph of the correlation. If the area where the heating element 4 and the movable member 8 overlap as in the form shown in FIG. 10A is large, the period of FIG. 10B becomes shorter than that of the form of FIG. Since the heating element 4 is closed in a short time after heating, it is more preferable. Note that the behavior of the movable member 8 in each of the periods (1) to (5) in FIG. 10B is the same as the behavior described with reference to FIG. 10A, the movable member 8 is more susceptible to the reduction in the volume of the bubbles 21. Therefore, as can be seen from the start of the period shown in FIG.
Is started immediately after the start of the partial growth partial contraction period. That is, the opening timing of the movable member 8 is earlier than in the case of the embodiment of FIG. For the same reason, the amplitude of the movable member 8 increases.

FIG. 11 is a diagram for explaining the correlation between the bubble growth and the behavior of the movable member 8 when the heating element 4 and the movable member 8 are separated from each other.
(B) shows a graph of the correlation. If the heating element 4 and the movable member 8 are separated from each other as in the form shown in FIG. 11A, the movable member 8 is less likely to be affected by the decrease in the volume of bubbles, so the period shown in FIG. As can be seen from the time point, the opening of the liquid supply port 5 by the movable member 8 is started considerably after the start of the partial growth partial contraction period. That is, the opening timing of the movable member 8 is later than in the case of the embodiment of FIG. For the same reason, the amplitude of the movable member 8 decreases. Note that the behavior of the movable member 8 in each of the periods (a) to (b) in FIG. 11B is the same as the behavior described with reference to FIG.

The positional relationship between the movable member 8 and the heating element 4 has been described for a general operation, and each operation differs depending on the position of the free end of the movable member 8, the rigidity of the movable member 8, and the like. It is a thing.

As can be seen from FIGS. 9 to 11, the maximum volume of the bubble (bubble in the region A) growing on the discharge port 7 side of the bubble generation region 11 is defined as Vf, and the liquid supply in the bubble generation region 11 is defined as Vf. Assuming that the maximum volume of the bubble (bubble in the region B) growing on the mouth 5 side is Vr, the relationship of Vf> Vr always holds in the head of the present invention. Furthermore, bubble generation area 1
The lifetime (time from the generation of bubbles to the disappearance of bubbles) of the bubble (bubble in the A region) growing on the side of the discharge port 7 of the first bubble is defined as Tf, and the bubble (B) growing on the liquid supply port 5 side of the bubble generation region 11 is defined as Tf. Assuming that the lifetime of the bubble in the region is Tr, Tf
> Tr always holds in the head of the present invention. Since the above relationship is established, the bubble erasing point is located closer to the discharge port 7 than near the center of the bubble generation region 11.

Further, in this head configuration, as can be seen from FIGS. 5 (b) and 7 (b), the amount h at which the free end of the movable member 8 is maximally displaced toward the liquid supply port 5 at the initial stage of the generation of the bubble 21.
There is a relationship (h1 <h2) that the amount h2 by which the free end of the movable member 8 is maximally displaced toward the bubble generating means 4 together with the defoaming of the bubble 21 is larger than 1. For example, h1 is 2 μm,
h2 is 10 μm. When this relationship is established, the growth of air bubbles behind the heating element (in the direction opposite to the discharge port 7) in the initial stage of foaming is suppressed, and the growth of air bubbles in front of the heating element (in the direction toward the discharge port 7) is suppressed. More can be promoted. As a result, it is possible to improve the efficiency of converting the bubbling power generated by the heating element 4 into the kinetic energy of the liquid droplet that flies from the discharge port 7.

As described above, the head configuration and the liquid discharging operation of the present embodiment have been described. According to such a mode, the growth component of the bubble 21 on the downstream side and the growth component on the upstream side are not uniform. In addition, there is almost no growth component to the upstream side, and the movement of the liquid to the upstream side is suppressed. Since the flow of the liquid to the upstream side is suppressed, most of the bubble growth component is directed to the direction of the discharge port 7 without loss to the upstream side, and the discharge force is remarkably improved. Moreover, the flow path from the liquid supply port 5 to the liquid flow path 3 is bent at the tip of the movable member 8 by the convex portion 5B formed on the supply section forming member 5A. The flow of the liquid to the liquid supply port 5 is sufficiently suppressed. As a result, the growth pressure of the bubble is reliably transmitted to the movable member 8, and the liquid flow path 3
Since the substantially sealed state is reliably created, the ejection characteristics can be further improved.

Further, the retreat amount of the meniscus after the discharge is reduced, and the amount of the meniscus protruding from the orifice surface at the time of refilling is also reduced accordingly. Therefore, meniscus vibration is suppressed, and stable ejection can be performed at all driving frequencies from a low frequency to a high frequency.

(Second Embodiment) In the head structure according to the first embodiment, the movable member 8 is not joined to the fixed member 9 as shown in FIGS. , Bent up) at the end 9A of the fixing member 9
Therefore, the opening area S is an area surrounded by the three sides of the liquid supply port 5 and the end 9A of the solid member 9; however, as shown in FIGS. 8 is fixed to the end portion 9 of the fixing member 9.
A may be used. In the case of this embodiment, the opening area S is an area surrounded by three sides of the liquid supply port 5 and the fulcrum 8A of the movable member 8 as shown in FIGS.

Further, in the head structure of the first embodiment, the liquid supply port 5 is an opening surrounded by four sides as shown in FIG. 3, but as shown in FIGS.
In the supply part forming member 5A (see FIG. 1), the wall surface on the liquid supply chamber 6 side opposite to the discharge port 7 side may be opened. In this case, as in the first embodiment, the opening area S is surrounded by three sides of the liquid supply port 5 and the end 9A of the fixing member 9 as shown in FIGS. Area.

Also in this case, similarly to the first embodiment, a convex portion 5B facing the free end of the movable member 8 is formed on the supply portion forming member 5A, and the liquid supply port 5 is formed at the tip of the movable member 8 from the liquid supply port 5. By bending the flow path leading to the liquid flow path 3, the flow of the liquid from the liquid flow path 3 to the liquid supply port 5 in the initial stage of firing can be suppressed, and the discharge characteristics can be further improved, and the bubbles can be improved. When the movable member 8 is displaced downward due to the partial defoaming, a liquid flows toward the heating element 4 at the free end of the movable member 8, and the downward displacement of the movable member 8 can be promoted.

(Third Embodiment) Next, a liquid ejection head according to a third embodiment will be described with reference to FIG.

In the liquid discharge head of the embodiment shown in FIG.
The element substrate 1 and the top plate 2 are joined, and a liquid flow path 3 having one end communicating with the discharge port 7 and the other end closed between the two plates 1 and 2.
Are formed.

A liquid supply port 5 is provided in the liquid flow path 3, and a common liquid supply chamber 6 communicating with the liquid supply port 5 is provided.

A movable member between the liquid supply port 5 and the liquid flow path 3 having one end facing the discharge port 7 as a free end and the other end supported by a support portion 9B at the upstream end of the liquid flow path 3 8 is provided substantially parallel to the opening area of the liquid supply port 5. The size of the movable member 8 is larger than the size of the opening area of the liquid supply port 5, and a small gap is formed between the upper surface of the liquid flow path 3 (the surface facing the heating element 4) and the upper surface of the movable member 8. Exists. A step portion 5C having a wall surface facing the free end of the movable member 8 via a small gap is formed on the upper surface of the liquid flow path 3. As a result, the flow path from the liquid supply port 5 to the liquid flow path 3 at the free end of the movable member 8 is bent.

As a result, while the movable member 8 can move in the liquid flow path 3 without frictional resistance, the displacement toward the opening area is restricted at the periphery of the opening area S, and the movable member 8 is moved from the liquid flow path 3 at the initial stage of foaming. The flow of the liquid to the liquid supply port 5 is suppressed. As a result, a substantially sealed state of the liquid supply port 5 can be reliably created, and the ejection characteristics are further improved. In addition, since the flow path from the liquid supply port 5 to the liquid flow path 3 is bent at the free end of the movable member 8, when the movable member 8 is displaced downward due to partial defoaming of bubbles, Since the liquid flows toward the heating element 4 at the free end of the movable member 8, the downward displacement of the movable member 8 can be promoted.

(Other Embodiments) Various embodiments suitable for a head using the liquid ejection principle of the present invention will be described below.

<Side Shooter Type> FIG. 17 is a sectional view of a so-called side shooter type liquid discharge head. In this description, the same reference numerals are used for the same components as those in the first embodiment. In the liquid discharge head of this embodiment, as shown in FIG. 17, the heating element 4 and the discharge port 7 face each other on a parallel plane, and the liquid flow path 3 is in the axial direction along the liquid discharge direction from the discharge port 7. It differs from the first embodiment in that it communicates at right angles. In such a liquid ejection head, an effect based on the same ejection principle as that of the first embodiment can be obtained.

<Movable Member> In the above-described embodiment, the material constituting the movable member may be a material having solvent resistance to the discharge liquid and having elasticity for operating well as the movable member. I just need.

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

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 appropriately and controlled to be used effectively.

By giving energy such as heat to the ink, a state change accompanied by a steep volume change (the generation of air bubbles) is caused in the ink, and the ink is ejected from the discharge port by the action force based on this state change. In the related art of an ink jet recording method for forming an image by adhering a liquid on a recording medium, that is, a so-called bubble jet recording method, FIG.
As indicated by the broken line 8, it can be seen that the heating element area and the ink ejection amount are in a proportional relationship, but there is a non-foaming effective region S that does not contribute to ink ejection. In addition, from the appearance of the 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. On the other hand, in the liquid discharge head of the present invention, since the liquid flow path including the bubble generating means is substantially shielded except for the discharge port, the maximum discharge amount is regulated. As shown, there is a region in which the ejection amount does not change even if the variation in the heating element area and the foaming power is large. By using this region, the ejection amount of large dots can be stabilized.

<Element Substrate> The configuration of the element substrate 1 provided with the heating element 10 for applying heat to the liquid will be described below.

FIG. 19 is a side sectional view of a main part of the liquid discharge head of the present invention. FIG. 19 (a) is a head having a protective film described later, and FIG. 19 (b) is a head having no protective film. It is.

A top plate 2 is arranged on the element substrate 1, and a liquid flow path 3 is formed between the element substrate 1 and the top plate 2.

The element substrate 1 is formed by forming a silicon oxide film or a silicon nitride film 106 for insulation and heat storage on a substrate 107 such as silicon, and forming a hafnium boride (HfB) constituting the heating element 10 thereon. ₂ ) The electric resistance layer 105 (0.01 to 0.2 μm thick) such as tantalum nitride (TaN) or tantalum aluminum (TaAl) and the wiring electrode 104 (0.2 to 1.0 μm thick) such as aluminum are shown. Patterning is performed as shown in FIG. A voltage is applied from the wiring electrode 104 to the resistance layer 105, and the resistance layer 10
5 is supplied with electric current to generate heat. On the resistance layer 105 between the wiring electrodes 104, a protective film 103 such as silicon oxide or silicon nitride is formed in a thickness of 0.1 to 2.0 μm, and further thereon, a cavitation resistant layer 102 (0.
(1 to 0.6 μm thick) to protect the resistance layer 105 from various liquids such as ink.

In particular, the pressure and shock waves generated during the generation and defoaming of bubbles are extremely strong, and significantly reduce the durability of a hard and brittle oxide film.
Are used as the anti-cavitation layer 102.

Further, depending on the combination of the liquid, the flow path configuration, and the resistance material, a configuration in which the above-described resistance layer 105 does not require the protective film 103 may be used, and an example thereof is shown in FIG. Examples of the material of the resistance layer 105 that does not require the protective film 103 include an iridium-tantalum-aluminum alloy.

As described above, the configuration of the heating element 4 in each of the above-described embodiments includes the above-described resistance layer 1 between the electrodes 104.
05 (heat generating portion) alone, or may include a protective film 103 for protecting the resistance layer 105.

In each of the embodiments, the heating element 4 having a heating portion composed of the resistance layer 105 that generates heat in response to an electric signal is used. However, the present invention is not limited to this.
What is necessary is just to generate bubbles in the foaming liquid sufficient to discharge the discharge liquid. For example, a light-to-heat converter that generates heat by receiving light from a laser or the like, or a heat generator that has a heat generating portion that generates heat by receiving a high frequency may be used.

The element substrate 1 includes a heating element 10 including a resistance layer 105 constituting the heating section and a wiring electrode 104 for supplying an electric signal to the resistance layer 105. A transistor, a diode, a latch for selectively driving the heating element 4 (electrothermal conversion element),
Functional elements such as shift registers may be integrally formed in a semiconductor manufacturing process.

Further, in order to drive the heating portion of the heating element 4 provided on the element substrate 1 as described above and discharge the liquid, the above-described resistance layer 105 is connected to the above-described resistance layer 105 through the wiring electrode 104 as shown in FIG. A rectangular pulse as shown is applied, and the wiring electrode 1
The resistance layer 105 between the layers 04 is heated rapidly. In the head of each of the above-described embodiments, the voltage is 24 V, the pulse width is 7 μsec, the current is 150 mA, and the electric signal is 6 kHz.
Then, the heating element was driven, and the liquid ink was ejected from the ejection port 7 by the operation described above.
However, the condition of the drive signal is not limited to this, and any drive signal can be used as long as it can appropriately foam the foaming liquid.

<Discharged Liquid> Among such liquids, as a liquid (recording liquid) used for recording, an ink having a composition used in a conventional bubble jet apparatus can be used.

In addition, liquids having low foaming properties, which have been difficult to discharge conventionally, liquids which are easily deteriorated or deteriorated by heat, and high-viscosity liquids can be used.

However, the properties of the discharged liquid are as follows:
It is desired that the liquid is not a liquid that does not hinder ejection, foaming, or operation of the movable member.

A high-viscosity ink or the like can be used as a recording discharge liquid.

In the present invention, recording was carried out using a dye ink having the composition shown in Table 1 as a recording liquid that can be used as a discharge liquid. The viscosity of this dye ink was 2 cP (2 × 10 ⁻³ Pa · s).

[0084]

[Table 1] Even when an ink having such a composition is used, the ejection force is improved and the ejection speed is increased by the liquid ejection head of the present invention, so that the landing accuracy of droplets is improved and a very good recorded image can be obtained.

<Flow Path Structure at Free End of Movable Member> FIG. 21 shows a supply section forming member 5A in which the liquid supply port 5 is formed.
5 is a cross-sectional view showing various shapes of the movable member 8 on a free end side. FIG.

FIG. 21A is different from the example shown in FIG.
The length of the opening of the liquid supply port 5 in the longitudinal direction of the movable member 8 is shortened, and the area where the upper surface of the movable member 8 faces the supply section forming member 5A is increased. This increases the length of the flow path from the liquid supply port 5 to the liquid flow path 3 and increases the flow resistance, thereby further suppressing the flow of the liquid from the liquid flow path 3 to the liquid supply port 5 in the initial stage of foaming. can do.

FIG. 21B is different from the example shown in FIG.
The protrusion height of the protrusion 5B of the supply portion forming member 5A is reduced,
The movable member 8 extends halfway in the thickness direction. As a result, although the length of the flow path from the liquid supply port 5 to the liquid flow path 3 is reduced, the flow path is still bent, and the flow of the liquid from the liquid flow path 3 to the liquid supply port 5 in the initial stage of foaming. Can be suppressed. Further, in this example, since the amount of overlap between the movable member 8 and the supply portion forming member 5A in the thickness direction of the movable member 8 is small, the movable member 8 is in close contact with the peripheral portion of the liquid supply port 5 due to the pressure of the bubbles. When the member 8 is displaced downward, a linear flow path can be formed between the liquid supply port 5 and the liquid flow path 3 with a smaller displacement amount than that shown in FIG. As a result, the liquid can be refilled more quickly.

FIG. 21 (c) shows the state of the supply section forming member 5A.
This is an example in which a surface facing the free end of the movable member 8 and a surface facing the upper surface are connected by a curved surface. As described above, even when the flow path from the liquid supply port 5 to the liquid flow path 3 is formed into a curved shape, similarly to the first embodiment, the flow from the liquid flow path 3 to the liquid supply port 5 in the initial stage of foaming is performed. The flow of the liquid can be suppressed, and the substantially closed state of the liquid flow path 3 can be reliably created. Further, in this example, the surface facing the free end of the movable member 8 and the surface facing the upper surface are curved, so that the liquid does not stagnate in this portion when the liquid is refilled, and the liquid supply port 5 The liquid can flow efficiently from the liquid flow path 3 to the liquid flow path 3.

Note that the example shown in FIG.
Has been described in the case of providing the supply portion forming member 5,
The present invention can be applied to a configuration like the third embodiment (see FIG. 16) in which the supply section forming member 5 is not used.

<Liquid Discharge Apparatus> FIG. 22 shows a schematic configuration of an ink jet recording apparatus which is an example of a liquid discharge apparatus to which the liquid discharge head having the structure described in the above-described various embodiments can be mounted. ing. The head cartridge 601 mounted on the ink jet recording apparatus 600 shown in FIG. 22 has a liquid ejection head having the above-described structure, and a liquid container for holding a liquid supplied to the liquid ejection head. Head cartridge 60
As shown in FIG. 22, a carriage 607 is engaged with a spiral groove 606 of a lead screw 605 that rotates via driving force transmission gears 603 and 604 in conjunction with forward and reverse rotations of a driving motor 602. It is installed. The head cartridge 60 is driven by the power of the drive motor 602.
1 is reciprocated with the carriage 607 along the guide 608 in the directions of arrows a and b. The inkjet recording apparatus 600 includes a recording medium transport unit (not shown) that transports a printing paper P as a recording medium that receives a liquid such as ink discharged from the head cartridge 601. The paper pressing plate 610 of the print paper P conveyed on the platen 609 by the recording medium conveying means presses the print paper P against the platen 609 in the moving direction of the carriage 607.

In the vicinity of one end of the lead screw 605, photocouplers 611 and 612 are provided. The photocouplers 611 and 612 are
07, the photocouplers 611 and 6
This is a home position detecting means for confirming the presence in the area No. 12 and switching the rotation direction of the drive motor 602. In the vicinity of one end of the platen 609, a support member 613 that supports a cap member 614 that covers the front surface of the head cartridge 601 having the discharge port is provided. In addition, an ink suction unit 615 that sucks ink that has been idly discharged from the head cartridge 601 and accumulated inside the cap member 614 is provided. The ink suction unit 615 performs suction recovery of the head cartridge 601 through the opening of the cap member 614.

The ink jet recording apparatus 600 is provided with a main body support 619. The moving member 618 is attached to the main body support 619 in the front-rear direction, that is, the carriage 6.
It is supported so as to be movable in a direction perpendicular to the direction of movement 07. The cleaning blade 617 is attached to the moving member 618. Cleaning blade 6
Reference numeral 17 is not limited to this form, and may be another form of a known cleaning blade. Further, the ink suction means 6
15 is provided with a lever 620 for starting suction in the suction recovery operation by the lever 15. The lever 620 moves with the movement of the cam 621 engaging with the carriage 607, and the driving force from the driving motor 602 switches the clutch. The movement is controlled by a known transmission means such as the like. An ink jet recording control unit for giving a signal to a heating element provided in the head cartridge 601 and controlling the driving of each mechanism described above is provided on the recording apparatus main body side.
It is not shown in FIG.

In the ink jet recording apparatus 600 having the above-described configuration, the head cartridge 601 reciprocates over the entire width of the print sheet P with respect to the print sheet P conveyed on the platen 609 by the recording medium conveying means. When a drive signal is supplied from a drive signal supply unit (not shown) to the head cartridge 601 during this movement, ink (recording liquid) is ejected from the liquid ejection head unit to the recording medium in accordance with the signal, and recording is performed. Done.

FIG. 23 is a block diagram of an entire recording apparatus for performing ink jet recording by the liquid ejection apparatus 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 printing apparatus, and at the same time, is converted into data that can be processed in the recording apparatus.
It is input to a CPU (central processing unit) 302 which also serves as a head drive signal supply unit. The CPU 302 stores data input to the CPU 302 based on a control program stored in a ROM (Read Only Memory) 303, into a RAM (Random Access Memory) 304.
And the like, and converted into data (image data) to be printed.

In order to record the image data at an appropriate position on the recording paper, the CPU 302 drives the driving motor 602 for moving the carriage 607 on which the recording paper and the head cartridge 601 are mounted in synchronization with the image data.
Create driving data to drive. The image data and the motor drive data are sent to the head cartridge 601 via the head driver 307 and the motor driver 305, respectively.
The image is transmitted to the driving motor 602 and is driven at a controlled timing to form an image.

Examples of the recording medium 150 used in such a recording apparatus, to which a liquid such as ink is applied, include plastics, cloth, aluminum, and the like used for various types of paper, OHP sheets, compact disks, decorative plates, and the like. Metal materials such as copper and copper, leather materials such as cow skin, pig skin and artificial leather, wood such as wood and plywood, ceramic materials such as bamboo materials and tiles, and three-dimensional structures such as sponges can be targeted.

Further, as this recording apparatus, various types of paper and O
A printer device for recording on an HP sheet or the like, a recording device for a plastic for recording on a plastic material such as a compact disc, a recording device for a metal for recording on a metal plate,
A recording device for leather that records on leather, a recording device for wood that records on wood, a recording device for ceramic that records on ceramic materials, a recording device that records on a three-dimensional network structure such as a sponge, or a fabric Also includes a textile printing device for performing recording on the paper.

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

[0100]

As described above, according to the present invention, the communication between the liquid flow path and the liquid supply port is immediately interrupted by the movable member when the air bubbles are generated in the air bubble generation area, and the liquid is discharged from the liquid flow path. Except for the outlet, by adopting a configuration that is substantially closed, the pressure wave due to the bubble growth in the bubble generation region does not propagate to the liquid supply port side and the liquid supply chamber side, and most of the pressure wave is discharged. Discharge power can be dramatically improved toward the outlet side. In addition, even if high-viscosity ink is used for the recording liquid in order to fix it on recording paper at high speed or to eliminate bleeding at the boundary between black and color, high-viscosity ink is improved by dramatically improving ejection power. Can be discharged. In addition, when the environment changes during printing, especially in a low-temperature, low-humidity environment, the ink thickening area increases at the ejection port, and the ink may not be ejected normally at the start of use. . Further, since the discharge power is dramatically improved, the size of the heating element used as the bubble generating means can be reduced, and the energy input for discharge can be reduced.

The free end of the movable member bends the flow path from the liquid supply port to the liquid flow path to suppress the flow of the liquid from the liquid flow path to the liquid supply port in the initial stage of foaming. A substantially closed state of the flow path can be reliably created, and the discharge characteristics can be further improved. Further, since the liquid hardly moves to the liquid supply chamber side, the retreat amount of the meniscus at the discharge port after the droplet discharge can be minimized. As a result, the time required for the meniscus to return to the initial state after the discharge is very short, that is, the time required to complete the replenishment (refill) of the ink in the liquid flow path is short, so that the ink discharge with high precision (quantity) can be performed. In the implementation, the ejection frequency (drive frequency) can also be dramatically improved.

Further, since the bubble growth in the bubble generation region grows greatly on the discharge port side and the growth on the liquid supply port side is suppressed, the bubble disappearing point is set from near the center of the bubble generation region to the discharge port side. And the defoaming force can be reduced while maintaining the foaming power, so that the mechanical and physical destruction life of the heating element due to the defoaming force in the bubble generation region can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid discharge head according to a first embodiment of the present invention, taken along one liquid flow direction.

FIG. 2 is a sectional view taken along line X-X 'of FIG.

FIG. 3 is a sectional view taken along line Y-Y 'of FIG.

FIG. 4 is a cross-sectional view of a flow path for explaining a “linear communication state”.

FIG. 5 is a cross-sectional view of the liquid discharge head having a structure shown in FIGS. 1 to 3 taken along a liquid flow path direction for explaining a discharge operation of the liquid discharge head, and distinguishing characteristic phenomena. It is shown.

6 is a cross-sectional view of the liquid discharge head taken along the direction of the liquid flow path in order to explain the discharge operation following FIG.

FIG. 7 is a cross-sectional view of the liquid discharge head taken along a liquid flow path direction for explaining a discharge operation subsequent to FIG. 6;

FIG. 8 is a diagram showing an isotropic growth state of bubbles in FIG. 5 (b).

9 is a graph showing a correlation between a time change of bubble growth in a region A and a region B in FIGS. 5 to 7 and a behavior of a movable member.

10 is a graph showing a correlation between a time change of bubble growth and a behavior of the movable member in a liquid ejection head having a different form from the relative position of the movable member and the heating element shown in FIG.

11 is a graph showing a correlation between a time change of bubble growth and a behavior of the movable member in the liquid ejection head having a different form from the relative position of the movable member and the heating element shown in FIG.

FIG. 12 is a cross-sectional view along one liquid flow direction of a liquid discharge head according to a first modification of the second embodiment of the present invention.

13 is a sectional view taken along line Y-Y 'of FIG.

FIG. 14 is a cross-sectional view of a liquid discharge head according to a second modification of the second embodiment of the present invention, taken along one liquid flow path direction.

15 is a sectional view taken along line Y-Y 'of FIG.

FIG. 16 is a diagram showing a liquid ejection head according to a third embodiment of the present invention.

FIG. 17 is a view for explaining an example of a side shooter type head to which the liquid ejection method of the present invention is applied.

FIG. 18 is a graph showing a relative relationship between a heating element area and an ink ejection amount.

FIGS. 19A and 19B are longitudinal sectional views of a liquid discharge head according to the present invention, in which FIG. 19A has a protective film and FIG. 19B does not.

FIG. 20 is a diagram of a waveform for driving a heating element used in the present invention.

FIG. 21 is a cross-sectional view for explaining various examples of a flow path structure that leads from the liquid supply port to the liquid flow path at the free end of the movable member.

FIG. 22 is a diagram showing a schematic configuration of a liquid ejection device equipped with the liquid ejection head of the present invention.

FIG. 23 is a block diagram of an entire apparatus for performing liquid discharge recording in the liquid discharge method and the liquid discharge head of the present invention.

FIG. 24 is a sectional view showing a state of a movable member in a conventional liquid ejection head.

[Explanation of symbols]

 Reference Signs List 1 element substrate 2 top plate 3 liquid flow path 4 heating element (bubble generating means) 5 liquid supply port 5A supply section forming member 5B convex section 5C stepped section 6 common liquid supply chamber 7 discharge port 8 movable member 9 support member 10 flow path Side wall 11 Bubble generation area 21 Bubble 22 Discharged droplet 102 Anti-cavitation layer 103 Protective film 104 Wiring electrode 105 Resistive layer 106 Silicon nitride film 107 Base 300 Host computer 301 Input / output interface 302 CPU 303 ROM 304 RAM 305 Motor driver 307 Head driver 600 Inkjet recording device 601 Head cartridge 602 Drive motor 603, 604 Drive transmission gear 605 Lead screw 606 Spiral groove 607 Carriage 607a Lever 608 Guide 609 Platen 610 Paper press plate 6 1,612 photocoupler 613 supporting member 614 cap member 615 ink suction means 617 cleaning blade 618 moves member 619 main support 620 lever 621 cams alpha, beta, gamma gap

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Kubota 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masanori Takenouchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. F-term (reference) 2C057 AF06 AF23 AF28 AF41 AF51 AG30 AG33 AG76 AN01 BA04 BA05 BA13

Claims (7)

[Claims] 1. A discharge port for discharging a liquid, a liquid flow path having an air bubble generation region for generating air bubbles in the liquid, one end of which is always in communication with the discharge port, and a liquid supplied to the liquid flow path. A liquid supply port opened to the liquid flow path for communicating the liquid supply chamber to be held with the liquid flow path; and a liquid supply port arranged in the liquid flow path facing the liquid supply port with a gap therebetween. One end of the road was supported as a free end,
A region surrounded by at least the free end and both sides continuous with the free end has a movable member larger than an opening region of the liquid supply port with respect to the liquid flow path, and is formed by the gap at the free end of the movable member. A flow path from the liquid supply port to the liquid flow path is bent. 2. The liquid discharge head according to claim 1, wherein the liquid flow path has a projecting portion at a position facing a free end of the movable member via a gap. 3. The liquid discharge head according to claim 1, wherein the discharge port and the bubble generation region are in a linear communication state. 4. The liquid supply port is substantially blocked by the movable member during a period in which all of the bubbles generated in the bubble generation region are growing substantially isotropically, and thereafter, the The movable member is displaced to the bubble generation region side during a period in which the portion on the discharge port side is growing and the portion on the movable member side is contracted, and the liquid is supplied from the liquid supply chamber through the liquid supply port. 2. The liquid discharge head according to claim 1, wherein the liquid discharge head can supply the liquid to the flow path. 5. A free end of the movable member is displaced toward the liquid supply port side in an initial stage of the generation of the bubble, and the liquid supply port is substantially shut off from the liquid flow path. 2. The liquid discharge according to claim 1, wherein a free end of the movable member is displaced toward the bubble generation region, and liquid can be supplied from the liquid supply chamber to the liquid flow path through the liquid supply port. head. 6. A liquid discharging apparatus comprising: the liquid discharging head according to claim 1; and a transport unit that transports a recording medium that receives liquid discharged from the liquid discharging head. 7. The liquid ejecting apparatus according to claim 6, wherein the recording is performed by ejecting ink from the liquid ejecting head and attaching the ink to the recording medium.