JP2000006405A - Liquid discharge head and liquid discharge apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and sufficiently transmit a pressure because of the generation of air bubbles to an entire bottom part of a pit by setting a distance between corner parts of the pit, a width of the bottom part of the pit and a width of a heat generation body in a section in an arrangement direction of discharge openings to be a range satisfying a specific ratio. SOLUTION: A discharge force is improved if a pit is designed to satisfy W1>=WH>=W2 when W1 is a distance between corner parts in a sectional direction of a flow passage, W2 is a width of a bottom part, W3 is a width between bend parts and WH is a width of a heat generation body. If W1>=W3>=WH, preferably, W1>=W3>=WH>=W2 is satisfied, a pressure because of the generation of air bubbles can be more efficiently transmitted to a movable separation film. With a motion of the movable separation film 5 being noted in this embodiment, a pit 8 is formed to the movable separation film 5 itself, which is moved towards a first flow passage by the growth of air bubbles generated at a front face of the heat generation body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid discharge head for discharging a desired liquid by generating bubbles due to thermal energy or the like, and more particularly, to a liquid discharge head using a movable separation film displaced by utilizing the generation of bubbles. About.

In the present invention, "recording" means not only giving a meaningful image such as a character or a figure to a recording medium, but also printing a meaningless image such as a pattern. It also means giving.

[0003]

2. Description of the Related Art By giving energy such as heat to ink, a state change accompanied by a steep volume change (formation of bubbles) is caused in the ink, and the ink is ejected from an ejection port by an action force based on this state change. An ink jet recording method in which an image is formed by attaching this to a recording medium, that is, a so-called bubble jet recording method, has been conventionally known.
A recording apparatus using this bubble jet recording method includes JP-B-61-59911 and JP-B-61-59914.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, an ejection port for ejecting ink, an ink flow path communicating with the ejection port, and an energy generating means for ejecting ink arranged in the ink flow path. A heating element (electric heat conversion element) is generally provided.

According to the above-described 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 excellent points such 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 been used in industrial systems such as textile printing devices.

On the other hand, in the conventional bubble jet recording method, heating is repeated while the heating element is in contact with the ink, so that deposits may be generated on the surface of the heating element due to scorching of the ink. In addition, in the case where the liquid to be discharged is a liquid which is easily deteriorated by heat or a liquid in which foaming is not sufficiently obtained, good discharge may not be performed by the above-described direct heating bubble formation by the heating element. .

[0006] On the other hand, the present applicant has disclosed in
Japanese Patent Application Laid-Open No. 81172/1999 proposes a method in which a foaming liquid is foamed by thermal energy through a flexible membrane that separates the foaming liquid and the discharge liquid, and the discharge liquid is discharged. In this method, the structure of the flexible film and the foaming liquid is such that the flexible film is provided on a part of the nozzle, whereas a structure using a large film that vertically separates the entire head is used. It is disclosed in JP-A-59-26270. This large film is provided for the purpose of preventing the liquids in the two liquid paths from being mixed with each other by being sandwiched between two plate members forming the liquid paths.

On the other hand, the foaming liquid itself is characterized by taking into account the foaming characteristics, as disclosed in JP-A-5-229122, which uses a liquid having a boiling point lower than that of the discharge liquid. Japanese Patent Application Laid-Open No. 4-329148 uses a liquid having the same as a foaming liquid.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have found a new problem which has not heretofore been involved in the displacement region of the movable separation film. That is, the separation membrane in the liquid ejection head of the present invention is sandwiched between the first liquid flow path wall and the second liquid flow path wall, and the movable area per nozzle is regulated by the liquid flow path wall. That is, it has been confirmed that the first and second liquid flow path walls regulate the displacement of the film and greatly affect the head characteristics.

[0009] This eventually affects the ejection efficiency and also affects the return mechanism of the film itself. Therefore, the present inventors concluded that it is important to always maintain a reliable discharge performance by regulating the displacement of the film itself, not the liquid flow path wall, and smoothing the displacement of the film. Reached.

Accordingly, the present inventors have conducted intensive studies to provide a liquid discharge head having excellent discharge stability and durability regardless of the type of liquid supplied, while taking advantage of the effect of the separation function of the separation membrane. . As a result, the present inventors focused on a separation membrane that does not substantially extend, provided a concave portion in the separation membrane,
It has been found that the displacement amount of the concave portion corresponds to the discharge amount of the discharge liquid. In other words, it has been found that, since the amount of ejection depends on the amount of displacement of the concave portion of the separation membrane, by setting the amount of displacement of the concave portion, stable ejection can be obtained irrespective of the type of supply liquid. Further, it has been found that the durability of the separation membrane is improved if the amount of displacement of the recess of the separation membrane is specified so that the depression does not expand and contract at the time of maximum displacement. Further, it has been found that if the self-restoring force is exerted when the energy for displacement is not applied to the recess, the refill of the discharged liquid is also improved.

From another viewpoint, when a wide variety of liquids are used as a discharge liquid, the discharge amount discharged from the discharge port communicating with the liquid flow path with energy such as heat is as follows.
It varies depending on the type of liquid. This variation tends to increase as the viscosity of the liquid increases. However, a method for stabilizing the discharge amount by changing the discharge energy according to the type of the supply liquid in one liquid discharge head becomes complicated, so that practical use is difficult. Therefore, it is also important to provide a head having a simple structure capable of obtaining stable ejection regardless of the type of supply liquid.

The present invention has been made as a result of such intensive studies, and it is possible to improve the discharge efficiency for discharging droplets, to further improve the discharge stability and discharge durability, and to improve the discharge droplets. It is an object of the present invention to provide an epoch-making liquid ejection head that stabilizes and increases the volume or the ejection speed.

According to the present invention, a first liquid flow path for a discharge liquid communicating with a discharge port, a second liquid flow path provided to supply or move a foaming liquid and including a bubble generation region, A liquid having a displacement region of the movable separation film upstream of the discharge port with respect to the flow direction of the discharge liquid in the first liquid flow channel using a liquid discharge head having a movable separation film for separating the second liquid flow channel; In a discharge head, discharge efficiency, discharge stability, and durability can be improved.

A first object of the present invention is to transmit a pressure to a discharge liquid by displacing a movable film by a force generated by a foaming pressure in a structure in which a discharge liquid and a foaming liquid are separated by a movable film. In this case, it is an object of the present invention to provide a liquid ejection head having excellent ejection efficiency, ejection stability, and refill efficiency by stabilizing the displacement of the movable separation film.

A second object of the present invention is to provide a liquid discharge head which can improve durability by the above-described structure.

A third object of the present invention is to reduce the amount of deposits deposited on the heating element and efficiently discharge the liquid without thermally affecting the discharge liquid by the above-described structure. It is an object of the present invention to provide a liquid ejection head that can perform the above-described operations.

A fourth object of the present invention is to provide a liquid discharge head having a wide selection degree regardless of the viscosity and material composition of the discharge liquid.

[0018]

To achieve the above object, a liquid discharge head according to the present invention comprises a first liquid flow path communicating with a discharge port for discharging a liquid, and a bubble generation region for generating a bubble in the liquid. And a movable separation membrane having a concave portion at a portion facing the bubble generation region, wherein the second liquid flow path and the first liquid flow path and the second liquid flow path are always substantially separated from each other. And at least a heating element that is provided at a position facing the movable separation film in the bubble generation region and generates heat for generating the bubbles, and the fulcrum of the recess has a corner portion that does not displace. At the same time, in a cross section in the arrangement direction of the discharge ports, when a distance between corners of the concave portion is W1, a width of a bottom portion of the concave portion is W2, and a width of the heating element is WH, W1 ≧ WH ≧ W2 is satisfied. It is characterized by the following.

Further, in the above-mentioned liquid discharge head, when a bent portion is provided between a corner portion and a bottom portion of the concave portion, and a distance between the bent portions of the concave portion is W3, W1 ≧ W3 ≧ WH is satisfied. Is preferred.

(Function) In the present invention configured as described above, with the generation and growth of bubbles in the bubble generation region, the movable separation film provided on the bubble generation region and having a recess is formed by the first liquid. Although it is displaced to the flow path side, the initial state of the concave portion and the shape of the concave portion at the time of maximum displacement are always constant by setting the fulcrum of the concave portion to a non-displaced corner portion, so that stable ejection can be obtained. In addition, since the concave portion returns to the initial state promptly after the maximum displacement due to the self-restoring force and the defoaming of the corner portion that is not displaced, the refill of the discharged liquid is improved.

Further, in the cross section in the arrangement direction of the discharge ports, when the distance between the corners of the recess is W1, the width of the bottom of the recess is W2, and the width of the heating element is WH,
By satisfying W1 ≧ WH ≧ W2, the pressure due to the generation of bubbles is efficiently and sufficiently transmitted to the entire bottom of the concave portion.
Further, in the inflection portion existing between the corner and the bottom of the recess, when the distance between the inflection portions of the recess is W3,
If W1 ≧ W3 ≧ WH, the pressure due to the generation of bubbles can be transmitted to the entire bottom of the recess more efficiently.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view in the flow channel direction for explaining an embodiment of the liquid discharge head of the present invention. FIG. 2 is an enlarged cross-sectional view around the concave portion of the movable separation film shown in FIG. FIG. 3 is a partially cutaway perspective view of the liquid ejection head of FIGS. 1 and 2.

In the present embodiment, as shown in FIG. 1, the first liquid supplied from the first common liquid chamber 143 is filled in the first liquid flow path 3 communicating with the discharge port 1. Further, the second liquid flow path 4 having the bubble generation region 7 is filled with a foaming liquid that is foamed by being given thermal energy by the heating element 2. First liquid flow path 3 and second liquid flow path 4
A movable separation membrane 5 for separating the first liquid flow path 3 and the second liquid flow path 4 from each other is provided. A concave portion 8 is provided in a portion of the movable separation membrane 5 facing the bubble generation region 7, and a corner 8 a is provided at a fulcrum of the concave portion 8,
A slack is formed in the first liquid flow path 3. In addition, the movable separation membrane 5 and the orifice plate 9 are closely fixed to each other,
Here, the liquids in the respective liquid flow paths do not mix. Note that, in the second liquid flow path 4, the vicinity of the projection area of the heating element 2 is the bubble generation area 7.

As shown in FIG. 3, the heating element 2 is
A plurality of second liquid flow paths 4 are provided on the element substrate 10 so as to correspond to the respective heating elements 2. Further, the support member 11 that supports the movable separation membrane 5 includes:
Each of the second liquid flow paths 4 also serves as a partition wall.
A plurality of concave portions 8 are formed in the movable separation film 5 so as to face the bubble generation region 7 near the projection region of each heating element 2.
A plurality of first liquid flow paths 3 are provided so as to include the respective concave portions 8. However, in FIG. 3, the positions where the walls 28 defining the respective first liquid flow paths 3 are placed are indicated by dotted lines.

In the present invention, attention is paid to the movement of the movable separation film 5, and a concave portion 8 is provided in the movable separation film 5 itself, and the concave portion of the movable separation film 5 is formed by the growth of bubbles generated on the surface of the heating element 2. 8 is displaced to the first liquid flow path 3 side.

In the initial state shown in FIGS. 1 and 2A, the liquid in the first liquid flow path 3 is drawn into the vicinity of the discharge port 1 by capillary force. In the present embodiment, the discharge port 1 is located on the downstream side in the liquid flow direction of the first liquid flow path 3 with respect to the projection area of the heating element 2 onto the first liquid flow path 3.

In this state, when heat energy is applied to the heating element 2 (a heating resistor having a shape of 40 μm × 105 μm in this embodiment), the heating element 2 is rapidly heated, and the heating element 2 in the bubble generation area 7 is heated. The surface in contact with the second liquid heats and foams the second liquid (FIGS. 1 and 2B). The bubbles 6 generated by the heating and foaming are bubbles based on a film boiling phenomenon as described in U.S. Pat. No. 4,723,129 and are generated simultaneously with an extremely high pressure over the entire surface of the heating element. It is. The pressure generated at this time becomes a pressure wave, propagates through the second liquid in the second liquid flow path 4, and acts on the movable separation membrane 5, thereby causing the concave portion 8 of the movable separation membrane 5 to move. As a result, the ejection of the second liquid in the first liquid flow path 3 is started. However, the corner 8a formed at the fulcrum of the recess 8 does not contribute to the deformation.

When the bubbles 6 generated on the entire surface of the heating element 2 grow rapidly, they form a film (FIGS. 1 and 2C). The expansion of the bubble 6 due to the extremely high pressure in the initial stage of the generation causes the concave portion 8 of the movable separation membrane 5 to be further deformed, whereby the discharge of the first liquid in the first liquid flow path 3 from the discharge port 1 proceeds. .

Thereafter, when the bubble 6 further grows, the deformation proceeds until the entire concave portion 8 except for the vicinity of the corner 8a of the movable separation membrane 5 enters the first liquid flow path 3 ((FIG. 1 and FIG. 2). d)).

Thereafter, when the bubble 6 contracts, the concave portion 8 of the movable separation film 5 starts to return to the position before the displacement (FIGS. 1 and 2).
(E)).

Thereafter, the recess 8 of the movable separation membrane 5 returns to the initial state shown in FIGS. 1 and 2 (f) promptly due to the self-restoring force provided by the non-displaced corner 8a as the bubble shrinks. Refilling in the first liquid flow path 3 is promoted.

Further, with the defoaming, the concave portion 8 of the movable separation film 5 is formed.
Is displaced into the second liquid flow path 4, the space in the second liquid flow path 4 becomes narrow, the filling amount of the foaming liquid becomes small, and the refill is completed quickly.

The corner 8a of the recess 8 has a function of suppressing rebound immediately after displacement due to foaming.
Is returned to the initial state immediately after the displacement, so that high-speed driving is possible.

FIG. 4 is a cross-sectional view of the liquid discharge head of the present invention, in which the concave portion 8 of the movable separation film 5 is enlarged in the flow channel direction.
Shows an initial state, and (b) shows a state at the time of maximum displacement. FIGS. 5A and 5B are comparative examples in which the fulcrum of the concave portion 8 of the movable separation film 5 has no corner and the shape at the time of maximum displacement is different, and FIG.
(B) shows a state at the time of the maximum displacement of the concave portion. FIG. 6 is a cross-sectional view of the liquid discharge head of the present invention in a horizontal direction with respect to the heating element.

As shown in FIG. 5, when the fulcrum 26 of the concave portion has no corner and the bottom 27 of the concave portion is inverted at the time of maximum displacement as shown in FIG. Deform as an inflection point.

On the other hand, when the fulcrum of the concave portion has the corner 8a, the corner 8a has an effect of always regulating the initial shape to a constant shape in the initial state shown in FIG. In addition, in the state of FIG. 4B at the time of the maximum displacement, the deformation does not concentrate on a local portion, but extends over a wide area near the corner, so that the shape at the time of the maximum displacement is always constant. That is, since the corner 8a regulates the initial state and the shape at the time of maximum displacement, extremely stable ejection is obtained, and the durability is improved. The displacement control region of the corner 8a can be understood from FIG.

FIG. 7 is an enlarged view of the vicinity of the concave portion of the movable separation film taken along the line AA in FIG. (A)-of this figure
(F) shows a step corresponding to (a) to (f) of FIG.

As shown in FIG. 7,
The distance between the corners is W1, the width of the bottom is W2, the distance between the inflections is W3, and the width of the heating element is WH. At this time, WH becomes W
If it is larger than 1, the pressure due to the generation of bubbles cannot be efficiently transmitted to the movable separation membrane, that is, the pressure is applied more than necessary due to the deformation of the concave portion.
Is smaller than W2, the pressure due to the generation of bubbles cannot be sufficiently transmitted to the entire bottom of the concave portion. Therefore, W
Designing the concave portion so as to satisfy 1 ≧ WH ≧ W2 leads to an improvement in ejection efficiency.

When W1 ≧ W3 ≧ WH, more preferably W1 ≧ W3 ≧ WH ≧ W2, the pressure due to the generation of bubbles can be transmitted to the movable separation membrane more efficiently. The “inflection portion” described in the specification and the drawings means a portion of the concave portion of the movable separation film that is most deformed at the time of maximum displacement.

Further, according to the configuration of the present embodiment, the discharge liquid and the foaming liquid can be made different liquids, and the discharge liquid can be discharged. For this reason, even if a high-viscosity liquid such as polyethylene glycol or the like, in which foaming is not sufficiently performed even when heat is applied conventionally and discharge power is insufficient, the liquid is supplied to the first liquid flow path 103. A liquid in which foaming is performed well in a foaming liquid (ethanol: water = 4: 6 mixed solution, about 1 to 2 cp, etc.)
Is supplied to the second liquid flow path 104, thereby enabling good ejection.

Also, by selecting a liquid that does not generate deposits such as kogation on the surface of the heating element even when it receives heat, foaming can be stabilized and good ejection can be performed.

Further, in the structure of the liquid discharge head of the present invention, since the effects described in the above embodiment are also produced, it is possible to discharge a liquid such as a highly viscous liquid with a higher discharge efficiency and a higher discharge force. it can.

Even when a liquid weak to heating is used, this liquid is supplied to the first liquid flow path 103 as a discharge liquid, and the second liquid flow path 104 is less likely to be thermally deteriorated and foams well. Is supplied without causing thermal harm to liquids that are weak to heating, and can be discharged with high discharge efficiency and high discharge force as described above.

Hereinafter, a heating element 1 for applying heat to a liquid will be described.
The configuration of the element substrate 110 provided with 02 is described.

FIGS. 8A and 8B are longitudinal sectional views showing one configuration example of the liquid discharge head of the present invention. FIG. 8A shows a device having a protective film described later, and FIG. FIG.

As shown in FIG. 8, on the element substrate 110,
The second liquid flow path 104, the movable separation film 105 serving as a separation wall having the concave portion 108, the movable member 131, the first liquid flow path 103, and the groove forming the first liquid flow path 103 are formed. The provided grooved member 132 is provided.

The element substrate 110 has a substrate 1 made of silicon or the like.
Silicon oxide on 10f for insulation and heat storage
A film or a silicon nitride film 110e is formed,
A heating element having a thickness of 0.01 to 0.2 μm is formed thereon.
Funium boride (HfB _Two ), Tantalum nitride
(TaN), electrical resistance of tantalum aluminum (TaAl), etc.
Layer 110d, 0.2-1.0 μm thick aluminum, etc.
And the wiring electrode 110c are patterned. this
Voltage is applied from the two wiring electrodes 110c to the electric resistance layer 110d.
Is applied, and a current is caused to flow through the electric resistance layer 110d to generate heat.
You. On the electric resistance layer 110d between the wiring electrodes 110c,
The protective layer 110b such as silicon oxide or silicon nitride
Formed in a thickness of 0.1 to 0.2 μm, and further thereon,
Cavitation resistance of 0.1 to 0.6 μm thick tantalum etc.
Layer 110a is formed, and various liquids such as ink
Protects the electrical resistance layer 110d.

In particular, the pressure and shock waves generated when bubbles are generated and defoamed are extremely strong, and the durability of a hard and brittle oxide film is significantly reduced.
Are used as the anti-cavitation layer 110a.

A structure that does not require the above-described protective layer may be used depending on a combination of a liquid, a liquid flow path structure, and a resistance material. An example is shown in FIG.

Examples of the material of the resistance layer that does not require such a protective layer include iridium = tantalum = aluminum alloy. In particular, in the present invention, since the liquid for foaming can be separated from the ejection liquid to be suitable for foaming,
This is advantageous when there is no protective layer.

As described above, the configuration of the heating element 102 in the above-described embodiment may include only the electric resistance layer 110d (heating section) between the wiring electrodes 110c, and may include a protective layer for protecting the electric resistance layer 110d. May be.

In the present embodiment, as the heating element 102,
Although a device having a heat generating portion composed of a resistance layer that generates heat in response to an electric signal was used, the present invention is not limited to this, and generates bubbles enough to discharge the discharge liquid in the foaming liquid. Anything should do. 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 unit that generates heat by receiving a high frequency may be used as the heat generating unit.

The above-mentioned element substrate 110 has an electric resistance layer 110d constituting a heating portion and an electric resistance layer 110d.
d, a functional element such as a transistor, a diode, a latch, a shift register, etc., for selectively driving the electrothermal transducer, in addition to the electrothermal transducer composed of the wiring electrode 110c for supplying an electric signal to the d. May be integrally formed by a semiconductor manufacturing process.

Further, in order to drive the heat generating portion of the electrothermal transducer provided on the element substrate 110 as described above and to discharge the liquid, the wiring electrode 110 is formed on the electric resistance layer 110d.
A rectangular pulse may be applied via c to cause the electric resistance layer 110d between the wiring electrodes 110c to generate heat sharply.

FIG. 9 shows the electric resistance layer 110d shown in FIG.
FIG. 5 is a diagram showing a voltage waveform applied to the.

In the liquid discharge head of the above-described embodiment, the heating element is driven by applying a voltage of 24 V, a pulse width of 7 μsec, a current of 150 mA, and an electric signal at 6 kHz, and the liquid is discharged from the discharge port by the above-described operation. A certain ink was ejected. However, the condition of the drive signal in the present invention is not limited to this, and may be any drive signal that can appropriately foam the foaming liquid.

As described above, in the present invention, the liquid can be ejected at a higher ejection force and ejection efficiency and at a higher speed than the conventional liquid ejection head by the structure in which the movable separation film has the concave portion. A liquid having the above-mentioned properties may be used as the foaming liquid, and specifically, methanol, ethanol, n-propanol, isopropanol, n-hexane, n-heptane, n-octane, toluene, xylene, methylene dichloride, Examples include trichlene, Freon TF, Freon BF, ethyl ether, dioxane, cyclohexane, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, water, and the like, and mixtures thereof.

As the discharge liquid, various liquids can be used irrespective of the presence or absence of foaming properties and thermal properties. Further, liquids having low foaming properties, which have been difficult to discharge in the past, liquids which are easily deteriorated or deteriorated by heat, and high-viscosity liquids can be used.

However, the properties of the discharged liquid are:
Alternatively, it is desired that the liquid does not hinder the ejection, foaming, operation of the movable separation membrane or the movable member, or the like due to the reaction with the foaming liquid.

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

As other discharge liquids, liquids such as medicines and perfumes which are weak to heat can be used.

Recording was performed by discharging a combination of a foaming liquid and a liquid having the composition shown below. As a result, more than 10 c
A liquid having a very high viscosity of 150 cp as well as a liquid having a p-viscosity could be ejected favorably, and a recorded matter of high image quality could be obtained. Foaming liquid 1 ethanol 40 wt% Water 60 wt% Foaming liquid 2 Water 100 wt% Foaming liquid 3 Isopropyl alcohol 10 wt% Water 90 wt% Discharge liquid 1 Carbon black 5 wt% (pigment ink about 15 cp) Stellene-acrylic acid-acryl Ethyl acid copolymer Separation material (oxidation 140, weight average molecular weight 8000) 1 wt% monoethanolamine 0.25 wt% glycerin 6.9 wt% thiodiglycol 5 wt% ethanol 3 wt% Water 16.75 wt% Discharge Liquid 2 (55 cp) Polyethylene glycol 200 100 wt% Discharge liquid 3 (150 cp) Polyethylene glycol 600 100 wt% By the way, in the case of the above-mentioned liquid which was conventionally difficult to be discharged, the discharge direction is low because the discharge speed is low. Variability in sex promotes Poor landing accuracy of recording paper dots, also by variation in the discharge amount due to unstable discharge occurs in these, high-quality image was difficult to obtain. However, in the configuration of the above-described embodiment, the generation of bubbles can be sufficiently and stably performed by using the foaming liquid. As a result, it was possible to improve the landing accuracy of the droplets and stabilize the ink ejection amount, and it was possible to significantly improve the quality of the recorded image.

Next, the manufacturing process of the liquid discharge head of the present invention will be described.

Roughly, a wall of the second liquid flow path is formed on the element substrate, a movable separation film is mounted thereon, and a groove or the like constituting the first liquid flow path is further provided thereon. Attach the grooved member. Alternatively, after forming the wall of the second liquid flow path, a head was manufactured by joining a grooved member having a movable separation membrane attached to the wall.

Further, a method for forming the second liquid flow path will be described in detail.

First, on an element substrate (silicon wafer),
Using a manufacturing apparatus similar to a semiconductor, an electrothermal conversion element having a heating element made of hafnium boride, tantalum nitride, or the like is formed, and then, in order to improve the adhesion with the photosensitive resin in the next step. The surface of the element substrate was cleaned. Further, in order to improve the adhesiveness, a liquid obtained by performing a surface modification on the element substrate surface with ultraviolet-ozone or the like and then diluting, for example, a silane coupling agent (manufactured by Nippon Yunika: A189) to 1% by weight with ethyl alcohol. May be spin-coated on the modified surface.

Next, an ultraviolet-sensitive resin film (manufactured by Tokyo Ohka:
Dry film Audil SY-318) was laminated.

Next, a photomask was provided on the dry film, and ultraviolet rays were irradiated to the portion of the dry film left as the second channel wall through the photomask.
This exposure step was performed using MPA-600 manufactured by Canon Inc., with an exposure amount of about 600 mJ / cm ² .

Next, the dry film was developed with a developing solution (BMRC-3, manufactured by Tokyo Ohka Kabushiki Kaisha) composed of a mixture of xylene and butyl cellosolve acetate, the unexposed portions were dissolved, and the exposed and cured portions were dissolved. Was formed as a wall portion of the second liquid flow path. Further, the residue remaining on the surface of the element substrate is subjected to an oxygen plasma ashing apparatus (MA manufactured by Alkantech Co., Ltd .:
S-800) for about 90 seconds to remove, followed by 2 hours at 150 ° C., and further 100 mJ /
cm ² was performed to completely cure the exposed areas.

According to the above-described method, the second liquid flow path can be uniformly formed with high accuracy on a plurality of heater boards (element substrates) divided and manufactured from the silicon substrate. That is, each silicon substrate was heated by a dicing machine (AWD-4000, manufactured by Tokyo Seimitsu) equipped with a diamond blade having a thickness of 0.05 mm.
And separated. The separated heater board was fixed on an aluminum base plate with an adhesive (manufactured by Toray: SE4400).

Next, the printed circuit board previously bonded on the aluminum base plate and the heater board were connected by an aluminum wire having a diameter of 0.05 mm.

Next, the joined body of the grooved member and the movable separation membrane was positioned and joined to the heater board thus obtained by the above-described method. That is, the grooved member having the movable separation film and the heater board are positioned and engaged and fixed by the pressing spring, and then the ink / foaming liquid supply member is joined and fixed on the aluminum base plate, and the gap between the aluminum wires and the groove is formed. The gap between the component, heater board, and the ink / foaming liquid supply member is filled with a silicone sealant (made by Toshiba Silicone: TSE).
(399).

By forming the second liquid flow path by the above-described manufacturing method, it is possible to obtain a high-precision flow path with no positional deviation with respect to the heater of each heater board. In particular, by joining the grooved member and the movable separation membrane in advance in the previous step, the positional accuracy of the first liquid flow path and the movable member can be improved. These high-precision and manufacturing techniques can stabilize ejection and improve print quality, and can be formed on a wafer at a time, so that a large amount can be manufactured at low cost. .

In this embodiment, an ultraviolet-curing dry film is used to form the second liquid flow path. However, a resin having an absorption band in the ultraviolet region, particularly around 248 nm, is used, and after lamination, It can also be obtained by curing and directly removing the resin in the portion that will become the second liquid flow path with an excimer laser.

The first liquid flow path and the like communicate with the orifice plate having the discharge port, the groove forming the first liquid flow path, and the plurality of first liquid flow paths in common. Is formed by joining a grooved top plate having a concave portion that constitutes a first common liquid chamber for supplying each of the liquid flows to the above-described combined body of the substrate and the movable separation film. The movable separation membrane is fixed by being sandwiched between the grooved top plate and the second liquid flow path wall. The movable separation film is not only fixed to the substrate side, but may be fixed to the grooved top plate and then positioned and fixed to the substrate as described above.

As the material of the movable separation membrane 105, in addition to the above-mentioned polyimide, polyethylene, polypropylene, polyamide, polyethylene terephthalate, melamine resin, phenol resin, polybutadiene, polyurethane,
Polyetheretherketone, polyethersulfone, polyarylate, silicone rubber, polysulfone,
Heat resistance, solvent resistance, and moldability are excellent, as represented by recent engineering plastics such as fluororesins, and resins that can be thinned, and their compounds, or durability,
It is desirable to use metals of silver, nickel, gold, iron, titanium, aluminum, platinum, tantalum, stainless steel, phosphor bronze, and compounds thereof, or silicon and silicon compounds, which are excellent in heat resistance and solvent resistance.

FIG. 10 is a view for explaining a step of manufacturing a movable separation film.

First, a mold 22 serving as a concave portion of a movable separation film is formed of a metal or resin on a silicon mirror wafer 21 as shown in FIG. Then, after a release agent is applied onto the mold 22, a liquid polyimide resin is spin-coated to form a film 23 as shown in FIG.

Thereafter, the film 23 was peeled off from the mirror wafer 11, positioned and attached on the substrate on which the second liquid flow path was formed, thereby producing a movable separation film.

However, the step of manufacturing the movable separation film can be performed by a method other than the spin coating method. For example, FIG.
As shown in (a), a commercially available thin film 24 serving as a movable separation membrane is used.
And a matrix 25 for forming a concave portion are prepared.
As shown in (b), the thin film 24 may be pressed against the matrix 25 and plastically deformed by heat to produce a movable separation film.

(Other Embodiments) FIG. 12 is a cross-sectional view in the flow channel direction for explaining another embodiment of the liquid discharge head of the present invention. FIG. 13 is an enlarged cross-sectional view around the concave portion of the movable separation film shown in FIG.

In this embodiment, as shown in FIGS. 12 and 13, the concave portion 8 of the movable separation film 5 has the inflection portion 8c between the corner 8a and the bottom portion 8b. The thickness is smaller than the thickness of the bottom 8b. Other configurations are the same as those of the above-described embodiment.

In the initial state shown in FIGS. 12 and 13A, the liquid in the first liquid flow path 3 is drawn to the vicinity of the discharge port 1 by capillary force. In the present embodiment, the discharge port 1 is located on the downstream side in the liquid flow direction of the first liquid flow path 3 with respect to the projection area of the heating element 2 onto the first liquid flow path 3.

In this state, when heat energy is applied to the heating element 2 (a heating resistor having a shape of 40 μm × 105 μm in the present embodiment), the heating element 2 is rapidly heated, and the heating element 2 The surface in contact with the second liquid causes the second liquid to be heated and foamed (FIGS. 12 and 13B). The bubbles 6 generated by the heating and foaming are bubbles based on a film boiling phenomenon as described in U.S. Pat. No. 4,723,129 and are generated simultaneously with an extremely high pressure over the entire surface of the heating element. It is. The pressure generated at this time becomes a pressure wave, propagates through the second liquid in the second liquid flow path 4, and acts on the movable separation membrane 5, thereby causing the concave portion 8 of the movable separation membrane 5 to move. Deformation starts at the inflection portion 8c, which is thinner than the others, and discharge of the second liquid in the first liquid flow path 3 is started. However, the corner 8a formed at the fulcrum of the recess 8 does not contribute to the deformation.

When the bubbles 6 generated on the entire surface of the heating element 2 grow rapidly, they form a film (FIG. 12 and FIG. 13C). The expansion of the bubble 6 due to the extremely high pressure in the initial stage of the generation causes the concave portion 8 of the movable separation membrane 5 to be further deformed, whereby the discharge of the first liquid in the first liquid flow path 3 from the discharge port 1 proceeds. .

Thereafter, when the bubble 6 further grows, the deformation proceeds until the entire concave portion 8 excluding the vicinity of the corner 8a of the movable separation membrane 5 enters the first liquid flow path 3 (FIGS. 12 and 1).
3 (d)). Since the displacement of the concave portion 8 from the initial state to the maximum displacement is easily performed by the inflection portion 8c which is thinner than the concave portion 8, the pressure due to the generation of bubbles can be efficiently guided to the discharge port side. In addition, the discharge efficiency can be improved.

Thereafter, when the bubble 6 contracts, the concave portion 8 of the movable separation film 5 starts to return to the position before the displacement (FIG. 12 and FIG. 13 (e)).

Thereafter, the concave portion 8 of the movable separation membrane 5 returns to the initial state shown in FIG. 12 and FIG. Refilling in the first liquid flow path 3 is promoted.

Further, with the defoaming, the concave portions 8 of the movable separation film 5 are formed.
Is displaced into the second liquid flow path 4, the space in the second liquid flow path 4 becomes narrow, the filling amount of the foaming liquid becomes small, and the refill is completed quickly.

The corner 8a of the recess 8 has a function of suppressing rebound immediately after displacement due to foaming.
Is returned to the initial state immediately after the displacement, so that high-speed driving is possible.

As described above, in the present embodiment, since the inflection portion 8c which is thinner than the other portion is provided between the corner 8a and the bottom 8c of the recess, the recess is easily deformed, and the pressure due to the generation of bubbles is efficiently discharged. It can be guided to the outlet side, and the discharge efficiency can be improved. Further, the liquid discharge head using the separation film has a configuration in which the movable separation film is sandwiched by flow path walls for forming the first liquid flow path and the second liquid flow path above and below the movable separation film. Therefore, in general, as the density of the nozzle increases, the portion existing between the flow path walls of the movable separation membrane becomes narrower, making it difficult to displace.However, the concave portion is easily deformed, which is sufficient for the higher density of the nozzle. It is also possible to provide a liquid ejection head that can perform the above operations.

FIG. 14 is an enlarged view of the vicinity of the concave portion of the movable separation film taken along the line AA in FIG. (A)-of this figure
(F) shows a step corresponding to (a) to (f) of FIG. As shown in FIG. 14, the distance between the corners in the cross-sectional direction of the flow path is W1, the distance between the bottoms is W2, the distance between the inflections is W3, and the width of the heating element is WH. At this time, WH becomes W3
If it is larger, the pressure due to the generation of bubbles cannot be efficiently transmitted to the movable separation membrane. That is, pressure is applied more than necessary due to deformation of the concave portion. Cannot be transmitted sufficiently to the entire bottom of the recess. Therefore, in addition to the effect of thinning the inflection portion described above, W1 ≧ WH ≧ W2
The design of the recess so as to satisfy the condition leads to an improvement in the discharge efficiency. Furthermore, if W1 ≧ W3 ≧ WH, more preferably W1 ≧ W3 ≧ WH ≧ W2, the pressure due to the generation of bubbles can be transmitted to the movable separation membrane more efficiently. FIG. 15 is a schematic perspective view showing an example of an ink jet recording apparatus which is a liquid discharge apparatus to which the above-described liquid discharge head is mounted. In FIG. 15, reference numeral 601 denotes an ink jet head cartridge in which the above-described liquid ejection head and ink tank are integrated, or the ink tank is detachable. The head cartridge 601 is mounted on a carriage 607 that engages 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 rotation of a driving motor 602. The carriage 607 is reciprocated along the guide 608 by the power of the drive motor 602 in the directions of arrows a and b.
A paper pressing plate 610 for a print sheet (recording material) P conveyed on a platen 609 by a recording medium supply device (not shown) presses the print sheet P against a platen roller 609 in the carriage movement direction.

In the vicinity of one end of the lead screw 605, photocouplers 611 and 612 are provided. These are home position detecting means for confirming the presence of the lever 607a of the carriage 607 in this area and switching the rotation direction of the drive motor 602 and the like.
In the figure, reference numeral 613 denotes a support member that supports a cap member 614 that covers the front surface of the above-described liquid discharge head having the discharge ports. Reference numeral 615 denotes an ink suction unit that sucks ink accumulated by the head 601, such as idle discharge, inside the cap member 614. The suction unit 615 performs suction recovery of the head 601 via the opening in the cap. Reference numeral 617 denotes a cleaning blade, and reference numeral 618 denotes a moving member that enables the blade 617 to move in the front-rear direction (a direction orthogonal to the moving direction of the carriage 607). The blade 617 and the moving member 618 are body support members. 619. The blade 617 is not limited to this form,
Other well-known cleaning blades may be used. Reference numeral 620 denotes a lever for starting suction in the suction recovery operation, and the cam 62 engaged with the carriage 607.
1 and the driving force from the driving motor 602 is controlled by a known transmission means such as clutch switching. An ink jet recording control unit for giving a signal to the heating element 202 provided on the head 601 and controlling the driving of each mechanism described above is provided on the apparatus main body side, and is not shown here.

In the ink jet recording apparatus 600 having the above-described configuration, the recording is performed while the head 601 reciprocates over the entire width of the printing paper P conveyed on the platen 609 by the recording material supply device (not shown). .

[0096]

As described above, according to the present invention, the concave portion is provided in the movable separation membrane for separating the first liquid flow path to which the discharge liquid is supplied and the second liquid flow path to which the non-discharged foaming liquid is supplied. Is provided so as to face the bubble generation region, and the fulcrum of the concave portion is set to a corner portion that is not displaced, so that the initial state of the concave portion and the shape at the time of maximum displacement are always constant, so that stable ejection can be obtained. Furthermore, the concave portion of the movable separation film quickly returns to the initial state due to the self-restoring force provided by the non-displaced corner portion along with the shrinkage of the bubble, thereby improving the refilling of the discharged liquid.

In the cross section in the arrangement direction of the discharge ports, when the distance between the corners of the recess is W1, the width of the bottom of the recess is W2, and the width of the heating element is WH,
By satisfying 1 ≧ WH ≧ W2, it is possible to efficiently and sufficiently transmit the pressure generated by the bubbles to the entire bottom of the concave portion. Further, in the inflection portion existing between the corner and the bottom of the recess, if the distance between the inflection portions of the recess is W3 and W1 ≧ W3 ≧ WH, the pressure due to the generation of air bubbles is reduced. Can be transmitted more efficiently to the entire bottom of the.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in a flow channel direction for describing an embodiment of a liquid discharge head of the present invention.

FIG. 2 is an enlarged cross-sectional view around a concave portion of the movable separation film shown in FIG.

FIG. 3 is a partially cutaway perspective view of the liquid ejection head of FIGS. 1 and 2;

FIGS. 4A and 4B are cross-sectional views of a liquid discharge head of the present invention in a flow direction in which a concave portion of a movable separation film is enlarged, where FIG.
(B) is a figure which shows the state at the time of the maximum displacement.

FIGS. 5A and 5B are comparative examples in which the fulcrum of the concave portion of the movable separation film has no corner portion and the shape at the time of maximum displacement is different from that of the liquid discharge head of the present invention. FIG. It is a figure showing the state at the time of displacement.

FIG. 6 is a cross-sectional view of a flow path in a horizontal direction with respect to a heating element of the liquid ejection head of the present invention.

FIG. 7 is an enlarged view around a concave portion of the movable separation film in a cross section taken along line AA of FIG. 1;

8A and 8B are cross-sectional views illustrating a configuration example of a liquid ejection head according to the present invention. FIG. 8A is a diagram illustrating a head having a protective film described later, and FIG. 8B is a diagram illustrating a head without a protective film. .

9 is a diagram showing a voltage waveform applied to the electric resistance layer shown in FIG.

FIG. 10 is a diagram for explaining a manufacturing process of a movable separation film of the liquid ejection head of the present invention.

FIG. 11 is a diagram for explaining another process of manufacturing the movable separation film of the liquid ejection head of the present invention.

FIG. 12 is a cross-sectional view in the flow channel direction for explaining another embodiment of the liquid ejection head of the present invention.

FIG. 13 is an enlarged cross-sectional view around the concave portion of the movable separation film shown in FIG.

14 is an enlarged view of the vicinity of a concave portion of the movable separation film in a cross section taken along line AA of FIG. 12;

FIG. 15 is a schematic perspective view showing an example of an ink jet recording apparatus which is a liquid ejection apparatus to which the liquid ejection head of the present invention can be attached and applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 101 Discharge port 2, 102 Heating element 3, 103 First liquid flow path 4, 104 Second liquid flow path 5, 105 Movable separation membrane 6, 106 Bubbles 7, 107 Bubble generation area 8, 108 Concave section 8a Square Part 8b bottom part 8c inflection part 10 element substrate 11 support member 21 mirror wafer (Si) 22 type 23 film 24 commercially available thin film 25 mother die 28 liquid flow path wall 110a anti-cavitation film 110b protective layer 110c wiring electrode 110d electric resistance layer 110e Silicon oxide film or silicon nitride film 143 First common liquid chamber 144 Second common liquid chamber W1 Distance between corners of concave portion of movable separation film W2 Width of bottom of concave portion of movable separation film W3 Distance between inflection portions of concave portions WH Width of heating element 600 Inkjet recording device 601 Inkjet head cartridge 602 Drive mode 603, 604 Driving force transmission gear 605 Lead screw 606 Helical groove 607 Carriage 607a Lever 608 Guide 609 Platen 610 Paper press plate 611, 612 Photocoupler 613 Supporting member 614 Cap member 615 Ink suction means 617 Cleaning blade 618 Body moving member 618 620 Lever 621 Cam P Print paper

Continuation of the front page (72) Inventor Fumi Yoshihira, 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Satoshi Shimazu 3-30-2, Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. F-term (reference) 2C057 AF04 AF06 AF51 AF70 AF71 AF93 AG46 AG53 AG58 AG98 AN01 AP02 AP11 AP22 AP24 AP57 BA05 BA13

Claims (9)

[Claims] A first liquid flow path that communicates with a discharge port that discharges a liquid; a second liquid flow path that includes a bubble generation region that generates bubbles in the liquid; and the first liquid flow path. A movable separation film having a concave portion at a portion facing the bubble generation region, which always substantially separates the second liquid flow path from each other, provided at a position facing the movable separation film in the bubble generation region; And at least a heating element that generates heat for generating the bubbles, wherein the fulcrum of the recess has a corner that does not displace, and in a cross section in the arrangement direction of the discharge ports, between the corners of the recess. A liquid discharge head satisfying W1 ≧ WH ≧ W2, where W1 is a distance, W2 is a width of a bottom of the recess, and WH is a width of the heating element. 2. A first liquid flow path communicating with a discharge port for discharging a liquid, a second liquid flow path including a bubble generation region for generating bubbles in the liquid, and the first liquid flow path. A movable separation film having a concave portion at a portion facing the bubble generation region, which always substantially separates the second liquid flow path from each other, provided at a position facing the movable separation film in the bubble generation region; At least a heating element that generates heat for generating the bubbles, the fulcrum of the recess has a corner that does not displace, and has an inflection between the corner and the bottom of the recess, In the cross section in the arrangement direction of the discharge ports, the distance between the corners of the recess is W1, the width of the bottom of the recess is W2, the distance between the inflections of the recess is W3, and the width of the heating element is WH. When
A liquid discharge head satisfying W1 ≧ W3 ≧ WH. 3. The liquid discharge head according to claim 2, wherein WH ≧ W2. 4. The liquid discharge head according to claim 2, wherein a thickness of the inflection portion of the concave portion is smaller than a film thickness of a bottom portion of the concave portion. 5. The liquid ejection head according to claim 1, wherein the bubble is a bubble generated by causing a film boiling phenomenon in the liquid by heat generated from the heating element. A liquid ejection head characterized by the above-mentioned. 6. The liquid discharge head according to claim 1, wherein a liquid supplied to the first liquid flow path and a liquid supplied to the second liquid flow path are provided. Are liquids different from each other. 7. The liquid ejection head according to claim 6, wherein the liquid supplied to the second liquid flow path has a lower viscosity than the liquid supplied to the first liquid flow path. A liquid ejection head characterized by being a liquid that is excellent in at least one property among foaming properties and thermal stability. 8. A liquid comprising: the liquid discharge head according to claim 1; and a recording medium transport unit that transports a recording medium that receives the liquid discharged from the liquid discharge head. Discharge device. 9. The liquid ejecting apparatus according to claim 8, wherein recording is performed by ejecting ink from the liquid ejecting head and attaching the ink to a recording medium.