JP2001138517A - Liquid jet head, liquid jet apparatus and liquid jet method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a novel liquid jet method enhancing both of liquid jet power and liquid jet frequency and achieving a high speed and high image quality head of a level incapable of being achieved heretofore. SOLUTION: Each of liquid flow channels 3 communicating with a jet orifice 7 at one end thereof and closed at the other end thereof is formed between an element substrate 1 and a top plate 2 and a heating element 4 for generating an air bubble in the liquid filling each liquid flow channel 3 is arranged on the element substrate 1 with respect to the liquid flow channel 3. Liquid supply ports 5 are arranged on a large number of the liquid flow channels 3 and a common liquid supply chamber 6 large in volume communicating with the liquid supply ports 5 is provided. A movable member 8 is provided between the liquid supply port 5 and the liquid flow channel 3 so as to form a fine gap α with respect to the forming surface of the liquid supply port 5 and has a region larger than the opening region of the liquid supply port 5. Liquid jet quantity Vd is larger than the maximum retreat quantity Vm of a meniscus M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid discharge method for discharging a liquid by applying thermal energy to the liquid to generate bubbles, a liquid discharge head and a method for manufacturing the same, and a liquid discharge using the liquid discharge head. Related to the device.

[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 (registered trademark) 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 flow path shape in order to obtain a liquid discharge head having a high filling (refilling) speed of the discharged liquid into the liquid flow path. Of these, in a head that generates bubbles in the nozzle and discharges liquid along with the bubble growth, bubble growth in the direction opposite to the discharge port and the resulting liquid flow are factors that lower the discharge energy efficiency and refill characteristics. A known invention having a structure for improving the discharge energy efficiency and the refill characteristics is proposed in European Patent Application Publication No. EPO436047Al.

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).
7Al (Figs. 4-9). For example, in the example of FIG.
As shown in FIG. 37, 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.

[0008]

However, EP4360
According to the invention described in 47Al, since the three areas of the area near the ejection port, the bubble generation section, and the ink supply section are divided into two chambers, the ink following 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 ink to the nozzles), the liquid is supplied to the bubble generating portion along with the defoaming, but the liquid cannot be supplied to the vicinity of the discharge port until the next bubble is generated. Not only is large but also the ejection response frequency is extremely small, which is not practical.

According to the present invention, there is provided 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 be found.

As a result of intensive studies, the inventors of the present invention have found that the function of a special check valve in a nozzle structure of a liquid discharge head that generates bubbles in a linearly formed nozzle and discharges liquid with the growth of the bubbles. As a result, it has been found that the growth of bubbles in the opposite direction (rearward) to the discharge port is suppressed, and the rearward discharge energy can be effectively used on the discharge port side. In addition, a special check valve function suppresses the backward bubble growth component and improves the efficiency of refill characteristics,
It has been found that the ejection response frequency can be extremely high.

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, and to achieve 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.

[0012]

According to the present invention obtained in the above-described research process, a plurality of discharge ports for discharging a liquid, one end of each of the discharge ports is always in communication, and a bubble is formed in the liquid. A plurality of liquid flow paths having a bubble generation region for generating bubbles, a bubble generation means for generating energy for generating and growing the bubbles, and each of the plurality of liquid flow paths is provided with a common liquid supply chamber. A plurality of liquid supply ports that communicate with each other, and a movable member having a free end supported with a small gap with respect to the liquid flow path side of the liquid supply port, and at least a free end of the movable member and An area surrounded by both sides continuous with the liquid supply port is larger than an opening area of the liquid supply port with respect to the liquid flow path. After a driving voltage is applied to the bubble generation means, the entire bubble is generated by the bubble generation means. Nearly isotropic growth A period during which the movable member hermetically closes and substantially blocks the opening region, and a period during which the movable member hermetically closes and substantially blocks the opening region. Thereafter, while the portion on the discharge port side of the bubbles generated by the bubble generating means is growing, the movable member starts to be displaced toward the bubble generating means in the liquid flow path, and A liquid discharge head capable of supplying a liquid from a liquid supply chamber to the liquid flow path, wherein a volume of a droplet discharged from the discharge port is set to Vd, and when a liquid is discharged from the discharge port, Vm is Vm next to the retracted body from the outlet to the liquid surface that retreats to the maximum in the liquid flow path.
Is characterized in that the relationship of Vd> Vm holds.

[0013] The minute gap between the movable member and the liquid supply port is preferably about 10 µm or less.

[0014] The direction in which the liquid is discharged from the discharge port is substantially perpendicular to the normal direction of the surface on which the bubble generating means is provided, or the discharge port faces the bubble generating means. Things are conceivable. The present invention also provides a liquid ejection apparatus including the above-described liquid ejection head, and a recording medium transport unit that transports a recording medium that receives liquid ejected from the liquid ejection head. In this case, it is conceivable to perform recording by ejecting ink from the liquid ejection head and attaching the ink to the recording medium.

In the above-described configuration, the liquid flow path is immediately provided between the time when the driving voltage is applied to the bubble generating means and the time when the entire bubble is substantially isotropically grown by the bubble generating means ends. The communication between the liquid supply port and the liquid supply port is blocked by the movable member, so that the pressure wave due to the bubble growth in the bubble generation area is not propagated to the liquid supply port side and the common liquid supply chamber side, and most of the pressure wave is discharged to the discharge port side And the discharge power is dramatically improved. In addition, even if a high-viscosity recording liquid is used in order to fix the recording liquid at high speed or eliminate bleeding at the boundary between black and color, the discharge power is dramatically improved. Good ejection can be achieved. In addition, when the environment changes during printing, especially in a low-temperature, low-humidity environment, the ink thickening region increases at the discharge port, and the ink may not be normally discharged at the start of use. However, in the present invention, it is possible to discharge well from the first shot. . 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.

In addition, the movable member is displaced toward the bubble generating means with the contraction of the bubble, and the liquid rapidly flows into the liquid flow path from the common liquid supply chamber through the liquid supply port, so that the discharged meniscus is reduced. The flow drawn into the liquid flow path from the discharge port rapidly decreases. As a result, the amount of meniscus retreat at the ejection port after droplet ejection is reduced. 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) is performed. In the implementation, the ejection frequency (drive frequency) can also be dramatically 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 a liquid from a liquid supply source to a discharge port via a bubble generation region (or a movable member).
Alternatively, it is expressed as an expression regarding this structural direction.

The “downstream side” of the bubble itself is as follows:
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.

The expression "the movable member seals and substantially shuts off the liquid supply port" in the present invention does not necessarily mean that the movable member is in close contact with the peripheral portion of the liquid supply port, and the movable member is a liquid supply port. This includes infinite access to the supply port.

[Detailed Description of the Invention] Next, an embodiment 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 of 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 is formed. The liquid flow paths 3 are provided in large numbers in one head. The element substrate 1 is provided with 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 for each of the liquid flow paths 3.
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.

Each of the plurality of liquid flow paths 3 is provided with a liquid supply port 5 formed in the supply section forming member 5A, and a common liquid supply chamber 6 communicating with each liquid supply port 5 is provided. 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. S in FIG. 1 is a substantial opening area for supplying a liquid to the liquid flow path 3 of the liquid supply port.

A movable member 8 is provided between the liquid supply port 5 and the liquid flow path 3 so as to be substantially parallel to the opening area S of the liquid supply port 5 with a small gap α (for example, 10 μm or less). Have been. An area surrounded by at least the free end of the movable member 8 and both sides continuous with the free end is an opening area S of the liquid supply port 5.
(See FIGS. 3A and 3B), and has a minute gap β between the side portion of the movable member 8 and each of the flow path side walls 10 on both sides (see FIGS. 2 and 3). The supply section forming member 5A described above has a gap γ with respect to the movable member 8 as shown in FIG. The gaps β and γ are different depending on the pitch of the flow path. However, if the gap γ is large, the movable member 8 can easily block the opening area S. Also easily moves toward the element substrate 1 with the defoaming. In the present embodiment, the gap α is 1 μm, the gap β is 4 μm, and the gap γ is 5 μm. Further, the movable member 8 has a width Wl larger than the width W2 of the opening region S in the width direction between the flow path side walls 10,
It has a width that can sufficiently seal the opening region S. 8B of the movable member 8 is a continuous portion (a part of which is shown in FIG. 1) in which the upstream end of the opening area S of the liquid supply port 5 is continuous in the direction in which the plurality of movable members intersect the plurality of liquid paths. As shown in FIG. 3) on the extension of the free end. In this embodiment, FIGS. 2 and 3
As shown in FIG. 5, the thickness of the portion of the supply section forming member 5A along the movable member 8 is set to be smaller than the thickness of the liquid flow path side wall 10 itself. Are laminated. The thickness of the supply port forming member 5A on the side closer to the discharge port 7 than the free end 8A of the movable member is set equal to the thickness of the liquid flow path wall 10 itself as shown in FIG. As described above, the movable member 8 can be moved in the liquid flow path 3 without frictional resistance, while the displacement toward the opening area S can be restricted at the periphery of the opening area S. Thereby, the opening area S
And the liquid flow from the inside of the liquid flow path 3 to the common liquid supply chamber 6 can be prevented. On the other hand, with the defoaming of bubbles, the liquid flow path side can be refilled from a substantially closed state. Can be moved to Further, in the present embodiment, the movable member 8 is also positioned parallel to the element substrate 1 with respect to the element substrate 1. An end 8B of the movable member 8 is a free end located on the heating element 4 side of the element substrate 1, and the other end is supported by a 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.

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 transducer and the discharge port 7, and the liquid flow is linear. It is in a “linear communication state” maintaining the 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 bubble discharge port side, are defined. 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 the present embodiment will be described in detail. FIGS. 5 and 6 show the liquid discharge head in a cutaway view along the liquid flow direction to explain the discharge operation of the liquid discharge head having the structure shown in FIGS. (A) to (d) of FIG.
It is shown separately in the steps (a) to (c) of FIG. Further, in FIGS. 5 and 6, 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 generates heat. In this state, there is a small gap (10 μm or less) between the movable member 8 provided between the liquid supply port 5 and the liquid flow path 3 and the surface on which the liquid supply port 5 is formed.

FIG. 5B shows a state in which a 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 in which bubble growth speed in any direction on the bubble surface in the direction perpendicular to the bubble surface is substantially equal.

In the isotropic growth process of the bubble 21 at the initial stage of the bubble generation, the movable material 8 comes into 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 becomes Except for the discharge port 7, a substantially closed state is achieved. This sealed state
This is maintained during any period of the isotropic growth process of the bubbles 21. The period during which the sealed state is maintained may be between the time when the driving voltage is applied to the heating element 4 and the time when the isotropic growth process of the bubbles 21 ends. Also,
In this closed state, the inertance of the liquid flow path 3 on the liquid supply port side from the center of the heating element 4 (the difficulty in moving the stationary liquid suddenly) becomes substantially infinite. At this time, the inertance from the heating element 4 to the liquid supply port side approaches infinity as the distance between the heating element 4 and the movable member 8 increases.

FIG. 5C shows a state in which the bubbles 21 continue to grow. As described above, when the inside of the liquid flow path 3 is substantially closed except for the discharge port 7, the liquid does not flow to the liquid supply port 5 side. Therefore, among the bubbles that have grown isotropically on the heating element 4, the bubble on the liquid supply port 5 side cannot grow, and the growth energy of the bubble is consumed only for the growth of the bubble on the discharge port 7 side.

Here, the bubble growth process in FIGS. 5A to 5C will be described in detail with reference to FIG. When the heating element is heated as shown in FIG. 7A, initial boiling occurs on the heating element, and thereafter, changes to film boiling in which film-shaped bubbles cover the heating element as shown in FIG. 7B. . The bubbles in the film boiling state continue to grow isotropically as shown in FIGS. 7B to 7C (the state in which 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) do not grow, and only the remaining downstream (discharge port side) part grows. FIGS. 5C, 7D, and 7E show this state.

Here, for convenience of explanation, when the heating element 4 is being heated, a region on the heating element 4 where no bubble grows is defined as a region B, and a region on the discharge port 7 side where the bubble grows is defined as a region A. In the region B, the foam volume during isotropic bubble growth is maximized.

Next, FIG. 5D 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 grow larger toward the ejection port side. Then, the volume of bubbles in the region B starts to decrease. Accordingly, the movable member 8 starts to be displaced downward to the steady state position by the restoring force due to its rigidity and the defoaming force of the bubbles in the B region. 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. 6A shows a state in which the bubble 21 has grown to a maximum. In this state, the bubbles grow in the region A to the maximum, and the bubbles in the region B almost disappear. Further, the ejection droplet 22 ejecting from the ejection port 7
Is still connected to meniscus M in a long tailed state. As shown in the figure, the maximum foaming volume of the bubbles is Vo.

FIG. 6B 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, the movable member 8 is displaced downward due to the contraction of the bubble, and 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 rapidly into the liquid flow path 3 is suddenly reduced, so that the retreat amount of the meniscus M is reduced and the meniscus M starts to return to the position before foaming at a relatively low speed. As a result, the convergence of the vibration of the meniscus M is very good as compared with the liquid ejection method having no movable member according to the present invention. Here, as shown in the figure, the discharge amount is Vd, and the maximum meniscus retreat amount, which is the drawing volume from the discharge port to the liquid surface that retreats maximally into the liquid flow path, is Vd.
m, and the amount of liquid that has moved into the liquid flow path 3 between the time when the free end of the movable member 8 starts to be displaced downward and the time when the retreat amount of the meniscus M becomes maximum is assumed to be Vr. Strictly speaking, the retreat amount of the meniscus M is maximum when the bubble 21 is completely defoamed. However, during the period from the state shown in FIG. Since the defoaming of the bubbles 21 is performed by the liquid flowing into the liquid flow path 3 from the common liquid supply chamber 6 via the liquid supply port 5, the retreat amount of the meniscus M in the state shown in FIG. Can be said to be substantially the maximum meniscus retreat amount Vm.

In FIG. 6C, the bubbles 21 completely disappear,
The state where the movable member 8 has also returned to the steady state position is shown. In this state, the movable member 8 is displaced upward by the elastic force (in the direction of the solid arrow in FIG. 6B). In this state, the meniscus M has already returned near the discharge port 7.

As can be seen from the above description and FIGS. 5 and 6, first, the movable member 8 moves the liquid to the liquid supply port 5 side at the initial stage of bubble generation and during the period when the bubble is growing isotropically. Suppress the flow of Then, when the ejected liquid flies by the ejection port 7 and flies, defoaming of the entire bubble has already started, and at that time, the movable member 8 is displaced downward, and the common liquid supply chamber 6 The liquid flows into the liquid flow path 3 via the liquid supply port 5.

That is, before the liquid separates from the liquid column, the flow of the liquid has started, so that the maximum meniscus retraction Vm is smaller than the volume caused by the discharge amount Vd of the flying liquid.

Therefore, the following relationship holds: Vd> Vm (1)

This means that the meniscus M can be returned quickly, thereby improving the refill frequency.

Further, the difference between the discharge amount Vd of the flying liquid and the maximum meniscus retraction product Vm is determined between the time when the free end of the movable member 8 starts to be displaced downward and the time when the retreat amount of the meniscus M becomes maximum. From the liquid amount Vr flowing into the liquid flow path 3,
It does not grow.

Therefore, Vd−Vm ≦ Vr...
The relationship of (2) holds.

Next, the fact that the relationship of Vd> Vm holds as described above means that the meniscus M is restored quickly, as shown in FIG.
This will be described with reference to FIG.

(A-1) to (a-7) of FIG.
FIG. 11 is a cross-sectional view along a liquid flow direction of a liquid ejection head according to a modification of the embodiment in which the relationship of Vm is satisfied;
(B-1) to (b-7) of FIG. 25 are cutaway views along the liquid flow direction of the liquid ejection head according to a comparative embodiment in which the relationship of Vd ′ <Vm ′ is satisfied. The positions of the heating elements 4 and 4 'are different from those of the liquid ejection head according to the present modification and the liquid ejection head according to the comparative example. The liquid discharge head according to the present modification and the liquid discharge head according to the comparative example are driven under the same driving conditions. FIG.
5 (a-1) to (a-7) and FIG. 25 (b-1) to
The states of the liquid ejection head shown in (b-7) substantially correspond to the states of the liquid ejection heads shown in FIGS. 5A to 5D and 6A to 6C, respectively. .

Here, FIGS. 25 (a-6) and 25 (b-
6), the respective maximum meniscus retreat amounts Vm and Vm ′ are substantially equal, but the liquid according to the modification of the present embodiment shown in FIG. The ejection amount Vd of the ejection head is larger than the ejection amount Vd ′ of the liquid ejection head according to the comparative example shown in FIG. 25B-6. This means that the liquid ejection head according to the modified embodiment of the present embodiment has higher ejection efficiency than the liquid ejection head according to the comparative embodiment, since the driving conditions of both are the same. In addition, when a driving condition is selected such that the ejection amounts of the two are the same, the liquid ejection head according to the modified embodiment of the present embodiment has a maximum meniscus than the liquid ejection head according to the comparative embodiment. It can be said that the amount of retreat is small. Therefore, it can be said that the liquid ejection head according to the modified example of the present embodiment in which the relationship of Vd> Vm is satisfied recovers the meniscus M faster than the liquid ejection head of the comparative example in which the relationship of Vd ′ <Vm ′ is satisfied. That is, that the relationship of Vd> Vm is satisfied means that the meniscus M returns quickly.

Next, the correlation between the time change of the bubble volume and the behavior of the movable member in the regions A and B shown in FIGS. 5 and 6 will be described with reference to FIG. FIG. 8 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. 8, 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. 8, since the bubble volume increases at the same time change in the initial stage of bubble generation, the curve A and the curve 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.
Thereafter, the curve A draws a curve that increases to the maximum point, but at some point the curve B branches off from the curve A and draws 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 covers a part of the heating element as shown in FIG. 1, the movable member behaves as follows. That is, in the period of FIG. 8, the movable member is displaced upward toward the liquid supply port. In the period shown in the figure, the movable member is in close contact with the liquid supply port, and the inside of the liquid flow path is substantially closed except for the discharge port. 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 is displaced downward toward the steady state position. The opening of the liquid supply port by the movable member is started after a lapse of a predetermined time from the start of the partial growth partial contraction period. Next, during the period shown in the figure, the movable member is further displaced downward from the steady state. Next, during the period shown in the figure, the downward displacement of the movable member is substantially stopped, and the movable member is in an equilibrium state at the open position. Finally, during the period shown in the figure, the movable member is displaced upward toward the steady state position.

The correlation between the bubble growth and the behavior of the movable member is affected by the relative position between the movable member and the heating element. Therefore, with reference to FIGS. 9 and 10, a correlation between bubble growth and fist movement of the movable member in the liquid ejection head including the movable member and the heating element at a relative position different from that of the present embodiment will be described.

FIG. 9 is a diagram for explaining the correlation between the bubble growth and the behavior of the movable member in the form in which the free end of the movable member covers the entire heating element. FIG.
(B) shows a graph of the correlation. If the area where the heating element and the movable member overlap is large as in the mode shown in FIG. 9A, the period in FIG. 9 is shorter than that in the mode in FIG. 1, and the heating element is heated. It is more preferable because the hermetically sealed state is obtained in a short time after the completion of the operation. In addition, the behavior of the movable member in each period from to in FIG. 9 is the same as the behavior described with reference to FIG. In addition, in the embodiment shown in FIG. 9, since the movable member is more susceptible to the reduction in the volume of bubbles, as can be seen from the start of the period in FIG. Immediately from the start. In other words, the opening timing of the movable member is
It is faster than the case of the form. For the same reason, the movable member 8
Becomes large.

FIGS. 10A and 10B are diagrams for explaining the correlation between the bubble growth and the behavior of the movable member when the heating element and the movable member are separated from each other. FIG.
Shows a graph of the correlation. (A) of FIG.
When the heating element and the movable member are separated as in the form shown in the figure, since the movable member is not easily affected by the decrease in the volume of the bubbles, as can be seen from the start of the period shown in FIG. The opening start is performed considerably later than the start of the partial growth partial contraction period. That is, the opening timing of the movable member is later than in the case of the embodiment of FIG. For the same reason, the amplitude of the movable member decreases. In addition, ~ of FIG.
The behavior of the movable member during each period 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, the rigidity of the movable member, and the like. It is. As described above, the head configuration and the liquid ejection operation of the present embodiment have been described. However, according to such a mode, the growth component of the bubble toward the downstream side and the growth component toward the upstream side are not equal, and Almost no growth component is present, 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 without loss of the bubble growth component to the upstream side, and the discharge force is remarkably 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.

Next, as shown in FIG. 1 to FIG.
An example of a manufacturing process in the case where the movable member 8, the channel side wall 10, and the liquid supply port 5 are provided above will be described with reference to FIGS. FIGS. 11 to 13 show the process by a cut surface along a direction orthogonal to the direction of the liquid flow path formed on the element substrate.

First, in FIG. 11A, an Al film is formed to a thickness of about 2 μm on the surface of the element substrate 1 on the side of the heating element 4 by a sputtering method. This formed Al film is patterned using a well-known photolithography process,
A plurality of Al film patterns 25 are formed at positions corresponding to the heating elements 2. Each of the Al film patterns 25 is formed by a support member 9 and a flow path side wall 10 in a step of FIG.
Extends to a region where the SiN film 26, which is a material film for forming a part of the SiN film, is etched.

The Al film pattern 25 functions as an etching stop layer when the liquid flow path 3 is formed by dry etching as described later. This is because the TiW layer as a pad protection layer, the Ta film as a cavitation-resistant film, and the SiN film as a protection layer on a resistor in the element substrate 1 are used to form an etching gas used to form the liquid flow path 3. Because it is etched by
Etching of these layers and films is prevented by the Al film pattern 25. Therefore, when the liquid flow path 3 is formed by dry etching, the surface of the element substrate 1 on the side of the heating element 4 and the TiW layer on the element substrate 1 are not exposed so that the liquid flow path 3 in each Al film pattern 25 is not exposed. The width in the direction perpendicular to the flow path direction is wider than the width of the liquid flow path 3 finally formed.

Further, at the time of dry etching, C
Decomposition of the F ₄ , C _X F _Y , and SF ₆ gases generates ionic species and radicals, which may damage the heating element 4 and the functional elements of the element substrate 1.
By receiving these ion species and radicals, the heating element 4 and the functional element of the element substrate 1 are protected.

Next, in FIG. 11B, a part of the channel side wall 10 is formed on the surface of the Al film pattern 25 and the surface of the element substrate 1 on the Al film pattern 25 side by using the plasma CVD method. Approximately 20.0 μm thick material film to be formed
Is formed so as to cover the Al film pattern 25.

Next, in FIG. 11C, after forming an Al film on the entire surface of the SiN film 26, the formed Al film is patterned by using a known method such as photolithography. An Al film (not shown) is formed on a portion of the surface excluding the portion where the liquid flow path 3 is formed. Then, the SiN film 26 is etched using an etching apparatus using dielectrically coupled plasma to form a part of the flow path side wall 10. In the etching apparatus, CF ₄ , O ₂ , SF
_The SiN film 26 is etched using the Al film pattern 25 as an etching stop layer by using the mixed gas of No. ₆ , etc. The constituent material of the contact portion between the support member 9 of the movable member 8 and the element substrate 1 includes TiW which is a constituent material of the pad protection layer,
And Ta as a constituent material of the anti-cavitation film of the element substrate 1.

Next, in FIG. 11D, an Al film 27 having a thickness of 2 was formed on the surface of the SiN film 26 by sputtering.
A hole formed by etching the SiN film 26 as a portion for forming the liquid flow path 3 in the previous process was formed as A.
Fill with l.

Then, in FIG. 12A, FIG.
The surfaces of the SiN film 26 and the Al film 2127 on the substrate 1 shown in FIG.
Polishing is performed flat by polishing.

Next, in FIG. 12B, an Al film 28 having a thickness of about 2.0 μm is formed on the surfaces of the SiN film 26 and the Al film 27 polished by CMP by a sputtering method. 28 is patterned using a well-known photolithography process. This Al film 28
In the process of FIG. 12C described later,
The SiN film 29, which is a material film for forming a pedestal portion (or a fixed portion) that forms a joint between the movable member 8 and the support member, extends to a region to be etched. Al
The film 28 functions as an etching stop layer when the movable member 8 is formed by dry etching as described later. That is, the SiN film 26 that becomes a part of the liquid flow path 3
This is to prevent the movable member 8 from being etched by an etching gas used to form the movable member 8.

Next, in FIG. 12C, a SiN film having a thickness of about 3.0 μm, which is a material film for forming the movable member 8, is formed on the surface of the Al film 28 by using the plasma CVD method. . Then, the formed SiN film is dry-etched using an etching apparatus using dielectrically-coupled plasma to leave a SiN film 29 at a position corresponding to the Al film 28 which is a part of the liquid flow path 3. The method using this etching apparatus is the same as the step in FIG. Since the SiN film 29 eventually becomes the movable member 8, the width of the pattern of the SiN film 29 in the direction orthogonal to the flow direction of the liquid flow path 3 is equal to the width of the finally formed liquid flow path 3. It is narrower than the width.

Next, in FIG. 13A, an Al film which is a material film for forming the gap forming member 30 is formed on the surface of the Al film 28 by a sputtering method so as to cover the SiN film 29. It is formed to have a thickness of 3.0 μm. The Al film formed on the Al film 28 in the previous step is patterned using a well-known photolithography process, and a gap α between the upper surface of the movable member 8 and the liquid supply port 5 shown in FIG. A gap forming member 30 for forming a gap β between the side walls 8 and the channel side wall 10 is formed on the surface and the side surface of the SiN film 29.

Next, in FIG. 13B, a negative photosensitive epoxy resin 31 made of a material shown in Table 1 below is placed on the SiN film 26 and the substrate including the gap forming member 30 made of an Al film is formed. It is applied to a thickness of 30.0 μm by spin coating. In addition, by the above-mentioned spin coating process,
The epoxy resin 31 which becomes a part of the channel side wall 10 to which the top plate 2 is joined can be applied flat.

[0066]

[Table 1] Subsequently, as shown in Table 1 above, after pre-baking the epoxy resin 31 at 90 ° C. for 5 minutes using a hot plate, an exposure apparatus (manufactured by Canon: MPA60) was used.
Exposure is performed on the epoxy resin 31 in a predetermined pattern with the exposure light amount of 2 [J / cm ² ] using the method (0). In the negative type epoxy resin, exposed portions are cured, and unexposed portions are not cured. Therefore, in the above-mentioned exposure step, only the portion excluding the portion serving as the liquid supply port 5 is exposed. Then, after forming a hole serving as the liquid supply port 5 using the above-described developer, the main baking is performed at 200 ° C. for 1 hour. The width of the opening of the hole serving as the liquid supply port 5 is smaller than the area of the SiN film 29 serving as the movable member 8.

Finally, in FIG. 13 (c), the Al films 25, 27, 28 and 30 are heated and etched using a mixed acid of acetic acid, phosphoric acid and sakiic acid to elute and remove them. A liquid supply port 5, a movable member 8, a support member 9, and a channel side wall 10 are formed on the element substrate 1. Thereafter, portions of the TiW film as the pad protection layer formed on the element substrate 1 corresponding to the heating element (bubble generating means) 4 and the pad are removed using hydrogen peroxide. T, which is a constituent material of the pad protection layer, is also provided at the contact portion between the element substrate 1 and the channel side wall 10.
iW and Ta which is a constituent material of the anti-cavitation film of the element substrate 1 are included.

As described above, the movable member 8, the flow path side wall 10, and the liquid supply port 5 are provided on the element substrate 1, and the large-capacity common liquid supply chamber 6 communicating with each of the liquid supply ports 5 simultaneously.
The liquid ejection heads shown in FIGS. 1 to 3 were manufactured by joining the top plate 2 provided with.

Next, a modified example of the above-described head form is shown in FIG.
This 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 is formed between the two plates 1 and 2.

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.

The movable member 8 has a small gap α between the liquid supply port 5 and the liquid flow path 3 with respect to the opening area of the liquid supply port 5.
(For example, 10 μm or less) and provided substantially in parallel. A region surrounded by at least the free end portion of the movable member 8 and both side portions continuous with the free end portion is larger than an opening region S of the liquid supply port 5 with respect to the liquid flow path. There is a small gap β between the side wall 10. As a result, the movable member 8 can move in the liquid flow path 3 without frictional resistance, and the displacement toward the opening area is regulated at the periphery of the opening area S, so that the liquid supply port 5 is substantially closed. 3
To the common liquid supply chamber 6 can be prevented. In the present embodiment, the movable member 8 is located to face the element substrate 1. One end of the movable member 8 is a free end that is displaced toward the heating element 4 side of the element substrate 1, and the other end is supported by the support 9.

(Second Embodiment) In the above-described manufacturing method, the manufacturing steps in the case where the movable member 8, the channel side wall 10, and the liquid supply port 5 are provided on the element substrate 1 have been described.
The present invention is not limited to this, and a process in which the movable member 8 and the liquid supply port 5 are formed on the top plate 2 side and joined to the element substrate 1 on which the channel side wall 10 is formed may be used.

Hereinafter, an example of this manufacturing process will be described with reference to FIG.
This will be described with reference to FIGS. FIGS. 14 and 15 show steps by a cut surface along a direction orthogonal to the direction of the liquid flow path formed on the element substrate. FIG.
FIG. 16 is a cross-sectional view of a schematic configuration of a liquid discharge head using the top plate created in FIGS. 4 and 15. In the description, the same reference numerals are used for the same components as those in the first embodiment.

First, in FIG. 14A, an oxide film (SiO ₂ ) 35 is coated on one surface of the top plate 2 made of Si material by about 1.0 μm.
m. Then, the formed SiO ₂ film 35 is
Patterning is performed using a well-known photolithography process to remove the SiO ₂ film corresponding to the formation location of the liquid supply port 5 shown in FIG.

Next, in FIG. 14B, the portion where the SiO ₂ film 35 is removed on one surface of the top plate 2 and the peripheral portion thereof
The gap forming member 36 made of a 1-film is covered by about 3.0 μm. The gap forming member 36 is for forming a gap between the liquid supply port 5 and the movable member 8 formed in a step shown in FIG.

Next, in FIG. 14C, the SiO ₂ film 35
The entire surface of the gap forming member 36 is coated with a SiN film 37 having a thickness of about 3.0 μm, which is a material film for forming the movable member 8, using the plasma CVD method so as to cover the gap forming member 36. Form.

Next, in FIG. 14D, the movable member 8 is patterned on the SiN film 37 by using a known photolithography process. Next, using the gap forming member as an etching stop layer, the Si top plate (thickness 6) is used.
(25 μm) to form the common liquid supply chamber. Then, Al as the gap forming member 36 is formed.
The film is heated and etched using a mixed acid of acetic acid, phosphoric acid and nitric acid to elute and remove the film. In the above-described patterning, the gap β between the movable portion 37a, which is the portion to be the movable member 8 in the SiN film 37, and the support portion 37b is set to 2 μm or more. In order to easily form the liquid supply port 5 corresponding to the movable member 8 in a step shown in FIG. 15A described later, the movable portion 37a of the SiN film 37 has a plurality of slits 37c penetrating the front and back surfaces thereof. Is preferably formed to a thickness of 1 μm or less. The projection area of the movable portion 37a is larger than the opening area of the portion serving as the liquid supply port (the removal area of the SiO ₂ film 35).

Next, in FIG. 15A, a portion of one surface of the Si top plate 2 from which the SiO ₂ film 35 has been removed is
The liquid supply port 5 is formed by anisotropic wet etching through the slit 37c of FIG.

Finally, in FIG. 15 (b), the thickness obtained by using the LPCVD method is about 0.
A 5 μm SiN film 38 is formed, and the slit 37 c opened in the movable member 8 is filled with the SiN film 38. At this time, since the gap of the slit 37c is set to 1 μm or less, the slit 37c is closed. Absent. Also,
The SiN film formed by the LPCVD method is also coated on the side wall of silicon formed by the anisotropic etching or the through etching of the silicon top plate, thereby preventing corrosion by ink.

As described above, the movable member 8 and the liquid supply port 5 provided on the top plate 2 side are further provided with a large-capacity common liquid supply chamber 6 communicating with each liquid supply port 5 simultaneously. A liquid flow path 3 having one end communicating with the discharge port 7 and the other end closed.
By joining the element substrate 1 having a flow path wall forming
The liquid ejection head shown in FIG. 16 was manufactured. The liquid discharge head of this embodiment has the same effect as the liquid discharge head having the structure shown in FIGS.

(Third Embodiment) FIG. 17 is a sectional view of a so-called side shooter type liquid discharge head according to a third embodiment of the present invention. In this description, the same reference numerals are used for the same components as those in the first embodiment. The liquid ejection head of this embodiment has the structure shown in FIG.
As shown in the figure, the heating element 4 and the discharge port 7 face each other on a parallel plane, and the liquid flow path 3 communicates at right angles to the axial direction along the discharge direction of the liquid from the discharge port 7. This is different from the first embodiment. In such a liquid discharge head as well, effects based on the same discharge principle as in the first embodiment can be obtained, and the manufacturing method described in the first and second embodiments can be easily applied.

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

<Movable Member> In the above embodiment, the material constituting the movable member may be a material which has solvent resistance to the discharge liquid and has elasticity to operate 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,
Resins such as liquid crystal polymer and its compounds, high ink resistance, metals such as gold, tungsten, tantalum, nickel, stainless steel, titanium, alloys of these and ink resistance, those coated on the surface or , A resin having an amide group such as polyamide,
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 (formation of bubbles) is caused in the ink, and the ink is ejected from the ejection port by an 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 where the ejection amount does not change even if the variation in the heating element area and the foaming volume is large. By using this region, the ejection amount of large dots can be stabilized.

Further, in order to form the above-mentioned substantially closed space well, 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> 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 a liquid discharge apparatus according to the present invention. FIG. 19A shows a head having a protective film described later, and FIG. 19B shows 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 base 107 made of silicon or the like, on which hafnium boron (HfB) constituting the heating element 10 is formed. 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 air bubbles are very strong, and significantly reduce the durability of a hard and brittle oxide film.
Are used as the anti-cavitation layer 102.

Further, a structure in which the protective layer 103 is not required for the above-described resistance layer 105 may be employed depending on the combination of the liquid, the flow path configuration, and the resistance material, and an example thereof is shown in FIG. Examples of the material of the resistance layer 105 that does not require such a 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 is such that the resistance layer 1 between the aforementioned electrodes 104 is formed.
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, in addition to the heating element 10 including the resistance layer 105 constituting the heating section and the 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. In addition, in order to drive the heat generating portion of the heat generating element 4 provided on the element substrate 1 as described above and discharge the liquid, as shown in FIG. By applying a simple rectangular pulse, the resistance layer 105 between the wiring electrodes 104 is heated rapidly. In the head of each of the above-described embodiments, the voltage was 24 V, the pulse width was 7 μsec, and the current was 150 m.
A, The heating element was driven by applying an electric signal at 6 kHz, and the ink as a liquid 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.

<Ejecting 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.

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

As the ejection liquid for recording, a high-viscosity ink or the like can be used.

In the present invention, recording was carried out using an ink having the following composition as a recording liquid that can be used as a discharge liquid. Drop landing accuracy is improved, and a very good recorded image can be obtained.

[0102]

[Table 2] <Liquid Discharge Apparatus> FIG. 21 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 first to third embodiments can be mounted. I have. The head cartridge 601 mounted on the ink jet recording apparatus 600 shown in FIG. 21 has a liquid ejection head having the above-described structure, and a liquid container for holding liquid supplied to the liquid ejection head. The head cartridge 601 is shown in FIG.
As shown in FIG. 1, mounted on a carriage 607 that engages with a spiral groove 606 of a lead screw 605 that rotates via drive force transmission teeth 603 and 604 in conjunction with forward and reverse rotation of a drive motor 602. I have. Drive motor 6
By the power of 02, the head cartridge 601 is reciprocated along the carriage 607 along the guide 608 in the directions of arrows a and b. Inkjet recording device 6
00 is provided with a recording medium transport unit (not shown) that transports a print sheet P as a recording medium that receives a liquid such as ink discharged from the head cartridge 601. The platen 6 is moved by the recording medium transport means.
09, a paper holding plate 610 for the printing paper P conveyed on
Presses the print paper P against the platen 609 over 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 the heating element provided in the head cartridge 601 and controlling the driving of each horizontal structure 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 structure, the head cartridge 601 reciprocates over the entire width of the print paper P with respect to the print paper P spread on the platen 609 by the above-described recording medium transport 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. 22 is a block diagram of the entire recording apparatus for performing ink jet recording by the liquid discharge apparatus of the present invention.

The printing 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 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 to convert the data into 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.

As the recording medium 150 used in such a recording apparatus and to which a liquid such as ink is applied, various types of paper, OHP sheets, plastic materials used for compact discs, decorative plates, etc., cloth, aluminum, etc. Metal materials such as copper and copper, leather materials such as cow skin, pig skin and artificial leather, wood materials 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 device, 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. In addition, as the ejection liquid used in these liquid ejection apparatuses, a liquid that matches each recording medium and recording conditions may be used.

[0111]

As described above, according to the present invention, the communication between the liquid flow path and the liquid supply port is immediately performed during the period when the bubble is generated by the bubble generating means and the bubble is growing substantially isotropically. A structure in which the liquid flow path is cut off by the movable member and the inside of the liquid flow path is substantially closed except for the discharge port, so that pressure waves due to bubble growth in the bubble generation area are supplied to the liquid supply port side and the common liquid supply. Most of the discharge power can be directed to the discharge port side without propagating to the chamber side, and the discharge power can be dramatically improved. In addition, in order to fix on recording paper at high speed, and to eliminate bleeding at the boundary between black and color,
Even when a high-viscosity recording liquid is used, high-viscosity ink can be satisfactorily ejected by a dramatic improvement in ejection power. 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.

Further, the movable member is displaced toward the bubble generating means with the contraction of the bubble, and the liquid rapidly flows into the liquid flow path from the common liquid supply chamber via the liquid supply port as a large flow. Accordingly, the flow of rapidly pulling the meniscus M into the liquid flow path is suddenly reduced, so that the amount of meniscus retreat at the discharge port after the droplet discharge is reduced. 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.

[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 path 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 diagram showing an isotropic growth state of bubbles in FIG. 5 (b).

8 is a graph showing a correlation between a time change of bubble growth in a region A and a region B shown in FIG. 4 and a behavior of a movable member.

9 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.

FIG. 10 is a graph showing a correlation between a time change of bubble growth and a behavior of a movable member in a liquid ejection head having a form different from a relative position between a movable member and a heating element shown in FIG. 1;

FIG. 11 is a diagram illustrating a method for manufacturing the liquid discharge head according to the first embodiment of the present invention.

FIG. 12 is a diagram illustrating a method for manufacturing the liquid discharge head according to the first embodiment of the present invention.

FIG. 13 is a diagram for explaining the method for manufacturing the liquid discharge head according to the first embodiment of the present invention.

FIG. 14 is a view illustrating a method of manufacturing the liquid discharge head according to the second embodiment of the present invention.

FIG. 15 is a view for explaining a method for manufacturing the liquid discharge head according to the second embodiment of the present invention.

FIG. 16 is a sectional view illustrating a schematic configuration of a liquid ejection head according to a second 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 diagram showing a schematic configuration of a liquid ejection device equipped with the liquid ejection head of the present invention.

FIG. 22 is a block diagram of an entire apparatus for performing liquid discharge recording in a liquid discharge method and a liquid discharge head of the present invention.

FIG. 23 is a sectional view showing a state of a movable member in a conventional liquid ejection head.

FIG. 24 shows a modification of the liquid ejection head according to the first embodiment of the present invention.

FIG. 25 is a cross-sectional view of the liquid discharge head along a liquid flow direction in order to explain a discharge operation of the liquid discharge head according to a modification of the first accurate mode of the present invention and a liquid discharge head according to a comparative example. And the characteristic phenomena are shown separately.

[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 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 discharge droplet 25 Al film pattern 26, 29, 37, 38 SiN film 27, 28 Al film 30, 36 Gap forming member 31 Photosensitive epoxy resin 35 SiO ₂ film 37a Movable portion 37b Support portion 37c Slit 39 Channel wall 102 Anti-cavitation layer 103 Protection Film 104 wiring electrode 105 resistive layer 106 silicon nitride film 107 substrate 201 silicon substrate 202 thermal oxide film 203 interlayer film 204 resistive layer 205 wiring 206 protective layer 207 anti-cavitation film 208 thermal action section 300 host computer 301 input / output interface 302 CPU 303 ROM 3 4 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 611, 612 Photocoupler 613 614 Cap member 615 Ink suction means 617 Cleaning blade 618 Moving member 619 Main body support 620 Lever 621 Cam α, β, γ Gap

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Kubota 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Masanori Takenouchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Masami Ikeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Sugitani 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. ( 72) The inventor: Takashi Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (12)

[Claims] 1. A plurality of discharge ports for discharging a liquid, a plurality of liquid flow paths having one end always connected to each of the discharge ports, and having a bubble generation region for generating bubbles in the liquid, Bubble generating means for generating energy for generating and growing; a plurality of liquid supply ports respectively provided in the plurality of liquid flow paths and communicating with a common liquid supply chamber; and the liquid flow path side of the liquid supply port. A movable member having a free end supported by a small gap with respect to the liquid flow path of the liquid supply port. It is larger than the opening area for the path, and from the time when the driving voltage is applied to the bubble generating means to the end of the period during which the entire bubble is substantially isotropically grown by the bubble generating means, Moving member in front A period in which the opening region is closed and substantially blocked, and after the period in which the movable member closes and substantially blocks the opening region, the ejection of the bubbles generated by the bubble generating means is performed. While the portion on the outlet side is growing, the movable member starts to be displaced toward the bubble generating means in the liquid flow path, and liquid can be supplied from the common liquid supply chamber to the liquid flow path. Wherein the volume of the droplets discharged from the discharge port is Vd, and when the liquid is discharged from the discharge port, from the discharge port to the liquid surface that retreats maximally into the liquid flow path. Volume of V
m, the relationship Vd> Vm is satisfied. 2. The liquid discharge head according to claim 1, wherein the movable member has a gap between the movable member and a liquid path wall forming the liquid flow path. 3. The liquid discharge head according to claim 1, wherein a minute gap between the movable member and the liquid supply port is about 10 μm or less. 4. The liquid discharge head according to claim 1, wherein the discharge port and the bubble generating unit are in a linear communication state. 5. The liquid ejecting apparatus according to claim 1, wherein a direction in which the liquid is discharged from the discharge port and a normal direction of a surface on which the bubble generating unit is provided are substantially orthogonal to each other. Item 6. The liquid ejection head according to Item 1. 6. The apparatus according to claim 1, wherein the discharge port faces the bubble generating means.
Item 6. The liquid ejection head according to Item 1. 7. A liquid discharge head according to claim 1, further comprising: a recording medium transport unit that transports a recording medium that receives a liquid discharged from the liquid discharge head. Liquid ejection device. 8. The liquid ejecting apparatus according to claim 7, wherein recording is performed by ejecting ink from the liquid ejecting head and attaching the ink to the recording medium. 9. A plurality of discharge ports for discharging a liquid, a plurality of liquid flow paths having one end constantly connected to each of the discharge ports, and having a bubble generation region for generating bubbles in the liquid, Bubble generating means for generating energy for generating and growing; a plurality of liquid supply ports respectively provided in the plurality of liquid flow paths and communicating with a common liquid supply chamber; and the liquid flow path side of the liquid supply port. A movable member having a free end supported by a small gap with respect to the liquid flow path of the liquid supply port. It is larger than the opening area for the path, and from the time when the driving voltage is applied to the bubble generating means to the end of the period during which the entire bubble is substantially isotropically grown by the bubble generating means, Moving member in front A period in which the opening region is closed and substantially blocked, and after the period in which the movable member closes and substantially blocks the opening region, the ejection of the bubbles generated by the bubble generating means is performed. While the portion on the outlet side is growing, the movable member starts to be displaced toward the bubble generating means in the liquid flow path, and liquid can be supplied from the common liquid supply chamber to the liquid flow path. A liquid ejection method for a liquid ejection head, wherein a volume of a droplet ejected from the ejection port is set to Vd, and when the liquid is ejected from the ejection port, the liquid retreats from the ejection port to the maximum in the liquid flow path. V is the drawing volume up to the liquid level
m, the following relationship is satisfied: Vd> Vm. 10. The liquid discharging method according to claim 9, wherein the movable member has a gap between the movable member and a liquid path wall forming the liquid flow path. 11. The liquid discharging method according to claim 9, wherein a minute gap between the movable member and the liquid supply port is about 10 μm or less. 12. The discharge port and the bubble generating means,
10. A linear communication state.
12. The liquid discharging method according to any one of items 1 to 11.