JPH09323420A - Liquid discharge head, liquid discharger, liquid discharge recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high discharge efficiency and high discharge pressure while improving the refilling of a discharge liquid by providing the first common liquid chamber higher in the vertical direction with a plane including a moving member at a stationary state than the first liquid channel, providing the fulcrum of the moving part in the first common liquid chamber and providing the free end at a stationary state in the first liquid channel. SOLUTION: The first common liquid chamber 13 is provided higher than the first liquid channel 14 in the vertical direction with a plane including a moving member 31 in a stationary state, the fulcrum 33 of the moving member 31 is provided in the first common liquid chamber 13, the free end 32 in a stationary state is provided in the first liquid channel 13. As a result, with the growth of bubbles 40, the moving member 31 is gradually displaced, directing the growth direction toward the outlet evenly. In the defoaming process, when the moving member 31 returns to its original position, the meniscus stops receding, the supply of a liquid equivalent to the cubic capacity W2 of bubbles remaining in the bubble occurrence area 11 side is suppressed by a liquid supply from a flow VD2 of the second liquid channel 16, the recession of the meniscus is reduced to half as much as W1 on the upper side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid ejection head for ejecting a desired liquid by generating bubbles by applying heat energy to the liquid, and in particular, utilizing the generation of bubbles. The present invention relates to a liquid ejection head having a movable member that displaces.

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.

[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 the ink onto a recording medium, that is, a so-called bubble jet recording method, is conventionally known. A recording device using this bubble jet recording method is USP
As disclosed in Japanese Patent No. 4,723,129 and the like,
Generally, an ejection port for ejecting ink, an ink channel communicating with this ejection port, and an electrothermal converter as an energy generating means for ejecting the ink disposed in the ink channel are disposed. ing.

According to such a recording method, a high-quality image can be recorded at high speed and with low noise, and in a head that performs 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 been used in industrial systems such as textile printing devices.

[0005] As the bubble jet technology is used for products in various fields, the following various requirements have been increasing in recent years.

[0006] For example, as a study on the demand for improving the ejection efficiency, optimization of the heating element such as adjusting the thickness of the protective film is mentioned. This method is effective in improving the efficiency of propagation of generated heat to the liquid.

Further, in order to obtain a high-quality image, a driving condition for providing a liquid discharging method or the like in which the ink discharging speed is high and good ink discharging based on stable bubble generation is proposed. From the viewpoint of high-speed printing, there has also been proposed a print head having 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 flow channel shapes, the flow channel structure is shown in FIG.
(A) and (b) are disclosed in JP-A-63-199997.
No. 2, for example. The flow channel structure and the head manufacturing method described in this publication use a back wave (pressure in the direction opposite to the direction toward the discharge port 18, that is, pressure toward the liquid chamber 54) generated by the generation of bubbles. ). This back wave is known as loss energy because it is not energy directed toward the ejection direction.

The invention shown in FIGS. 6 (a) and 6 (b) discloses a valve 55 which is located farther from the bubble generation region formed by the heating element 2 and which is located on the opposite side of the heating element 2 from the discharge port 18. To do.

In FIG. 6 (b), this valve 55 has an initial position as if it was attached to the ceiling of the liquid flow path 10 by a manufacturing method using a plate material or the like, and the liquid flow with the generation of bubbles. It is disclosed as hanging down into the lane 10.
The present invention is disclosed as controlling the energy loss by controlling a part of the back wave by the valve 55.

However, in this configuration, as can be seen by examining the case where bubbles are generated inside the liquid flow path 10 for holding the liquid to be discharged, it is necessary to suppress a part of the back wave by the valve 55. It can be seen that it is not practical for ejection.

Originally, the back wave itself is not directly related to the ejection as described above. At the time when this back wave is generated in the liquid flow path 10, as shown in FIG. 6B, the pressure of the bubbles, which is directly related to the discharge, has already made the liquid dischargeable from the liquid flow path 10. Therefore, it is clear that even if only a part of the back wave is suppressed, the ejection is not greatly affected.

Further, an invention of a head which improves refilling of a recording liquid and is excellent in frequency response is disclosed in JP-A-63-199.
No. 972. According to the present invention, the sub flow path is provided and communicated near the heater of the nozzle.
At the time of refilling, ink is also supplied from this sub-channel to shorten the refilling time.

However, in the head having such a structure, a part of the ejection force generated at the time of bubbling escapes to the sub-flow path, which may cause a decrease in ejection efficiency. On the other hand, in the bubble jet recording method, heating is repeated while the heating element is in contact with the ink, so that deposits due to scorching of ink are generated on the surface of the heating element. As a result, the generation of bubbles becomes unstable, and it may be difficult to perform good ink ejection. Further, even in the case where the liquid to be discharged is a liquid that is easily deteriorated by heat or a liquid in which foaming is difficult to be sufficiently obtained, a liquid discharge head for discharging the liquid to be discharged without changing the quality of the liquid to be discharged is desired. I was

[0015] From such a viewpoint, the liquid (foaming liquid) that generates bubbles by heat and the liquid (ejected liquid) to be ejected are separated liquids, and the ejected liquid is ejected by transmitting the pressure due to foaming to the ejected liquid. The method is described in JP-A-61-69467, JP-A-55-81172, US Pat.
No. 0,259, and the like. In these publications, the ink, which is the ejection liquid, and the foaming liquid are completely separated by a flexible film such as silicon rubber so that the ejection liquid does not come into direct contact with the heating element, and the pressure due to the foaming of the foaming liquid is controlled. The configuration is such that the liquid is transmitted to the discharge liquid by deformation of the flexible film.
Such a configuration achieves prevention of deposits on the surface of the heating element, improvement in the degree of freedom in selecting the liquid to be discharged, and the like.

However, as described above, in the head having a structure in which the discharge liquid and the foaming liquid are completely separated, the pressure at the time of foaming is transmitted to the discharge liquid by expansion and contraction deformation of the flexible film. Is considerably absorbed by the flexible membrane. In addition, since the amount of deformation of the flexible film is not so large, the effect of separating the ejection liquid and the foaming liquid can be obtained, but there is a possibility that the ejection efficiency and the ejection force are reduced.

As described above, in recent years, the bubble jet technology has been used in various fields, and in such circumstances, the degree of freedom in selecting the characteristics of the discharge liquid, including viscosity and thermal properties, has been expanded. There is a demand for a liquid ejection head that can perform good ejection.

[0018]

SUMMARY OF THE INVENTION The present invention is based on the fundamental discharge characteristics of a conventional system in which a bubble (particularly a bubble accompanying film boiling) is formed in a liquid flow path to discharge a liquid. The main task is to raise the level to a level that cannot be predicted in the past, from a viewpoint that could not be considered in the past.

Some of the inventors went back to the principle of droplet discharge and conducted intensive research to provide a novel droplet discharge method utilizing bubbles which could not be obtained conventionally and a head and the like used therefor. . At this time, the first technology analysis starting from the operation of the movable member in the liquid flow path, which is to analyze the principle of the mechanism of the movable member in the flow path, and the second technology starting from the principle of discharging droplets by bubbles The analysis, and further, the third analysis starting from the bubble formation region of the heating element for forming bubbles is performed.

Based on these analyses, the arrangement of the fulcrum and the free end of the movable member is determined to be such that the free end is located on the discharge port side, that is, on the downstream side, and the movable member faces the heating element or the bubble generation area. This has led to the establishment of a completely new technology for actively controlling air bubbles.

Next, it has been found that considering the energy that the bubble itself gives to the ejection amount, consideration of the growth component on the downstream side of the bubble is the largest factor that can significantly improve the ejection characteristics. That is, it has been found that the efficient conversion of the growth component on the downstream side of the bubble in the ejection direction leads to the improvement of the ejection efficiency and the ejection speed. From this,
Some of the inventors have reached a state of the art that is extremely higher than the state of the art in which the growth component downstream of the bubble is positively moved to the free end side of the movable member.

Further, a heat generating area for forming bubbles,
For example, a structural element such as a movable member or a liquid flow path that is involved in the growth of the downstream side of the bubble, such as the area center on the surface that controls foaming, downstream from the center line passing through the area center in the liquid flow direction of the electrothermal converter. It has been found that it is also preferable to take into account the above.

Some of the inventors and the applicant of the present invention have applied for the knowledge obtained in the above research and the principle of excellent liquid ejection from a comprehensive viewpoint. Based on the invention, we came up with a more desirable idea.

What has been particularly noted in the present invention has led to a very effective and rational technique in which refilling is significantly improved by taking into consideration the arrangement of movable members and the structure of the liquid supply path. .

The main object of the present invention is as follows: The first object of the present invention is to prevent back waves by the valve mechanism of the movable member and at the same time reduce the resistance that the discharge liquid receives from the liquid flow path. It is to provide a liquid ejection head with improved refill.

A second object of the present invention is to suppress the action of inertial force in the direction opposite to the liquid supply direction due to the back wave, and at the same time reduce the meniscus retreat amount by the valve mechanism of the movable member. Another object of the present invention is to provide a liquid ejection head having a higher refill frequency and a higher printing speed.

A third object of the present invention is to provide a liquid discharge head in which the resistance received from the liquid flow path is reduced when the valve mechanism of the movable member is actuated by the generation of bubbles to improve the discharge efficiency. is there.

A fourth object is to provide an extremely novel liquid discharge head by fundamentally controlling generated bubbles.

A fifth object of the present invention is to improve discharge efficiency and discharge pressure, to significantly reduce heat accumulation in the liquid on the heating element, and to reduce residual bubbles on the heating element. Another object of the present invention is to provide a liquid ejection head that can perform good liquid ejection.

A sixth object of the present invention is to provide a liquid discharge head capable of reducing deposits on a heat generating element, widening the range of use of the discharge liquid, and having sufficiently high discharge efficiency and discharge force. To provide.

A seventh object of the present invention is to provide a liquid ejection head which can increase the degree of freedom in selection of liquid to be ejected.

An eighth object of the present invention is to provide a method of manufacturing a liquid discharge head which can easily manufacture the above-described liquid discharge head.

A ninth object of the present invention is to provide a head which is easy to manufacture and inexpensive by constructing a liquid introduction path for supplying a plurality of liquids with a small number of parts, and also a liquid which can be miniaturized. It is to provide an ejection head.

[0034]

A typical requirement of the present invention to achieve the above object is as follows.

A discharge port for discharging a liquid, a bubble generation region for generating bubbles in the liquid, a bubble generation region facing the bubble generation region, and a first position and a bubble generation region more than the first position. A movable member displaceable from a distant second position, the movable member moving from the first position to the second position by a pressure based on the generation of bubbles in the bubble generating unit. A liquid ejecting head that is displaced, and ejects liquid by expanding the air bubbles to a larger extent downstream than in the direction toward the ejection port by the displacement of the movable member, wherein the first common liquid chamber is the first Above the liquid flow path in the direction perpendicular to the plane including the stationary movable member, the fulcrum of the movable member is present in the first common liquid chamber, and the free end in the stationary state is the first liquid flow. Liquid ejection head that exists in the road.

Alternatively, a discharge port for discharging a liquid, a heating element for generating bubbles in the liquid by applying heat to the liquid, and a liquid along the heating element from the upstream side of the heating element onto the heating element A liquid flow path having a supply path for supplying and a free end provided on the discharge port side facing the heating element, and displacing the free end based on the pressure generated by the generation of the bubbles And a movable member that guides the movable member to the discharge port side, wherein the first common liquid chamber is higher than the first liquid flow path in a direction perpendicular to a surface including the movable member in a stationary state, A liquid discharge head in which a fulcrum of the member is present in the first common liquid chamber, and a free end in a stationary state is present in the first liquid flow path.

Alternatively, a discharge port for discharging the liquid, a heating element for generating bubbles in the liquid by applying heat to the liquid, and a free end provided on the discharge port side facing the heating element A movable member that displaces the free end based on the pressure caused by the generation of bubbles to guide the pressure to the discharge port side, and a liquid on the heating element from the upstream side along the surface of the movable member near the heating element. And a supply path for supplying the liquid, wherein the first common liquid chamber is higher than the first liquid flow path in a direction perpendicular to a plane including the movable member in a stationary state, and the fulcrum of the movable member is A liquid discharge head that exists in the first common liquid chamber and has a free end in a stationary state that exists in the first liquid flow path.

Alternatively, the first liquid flow path communicating with the discharge port, the second liquid flow path having a bubble generation region for generating bubbles in the liquid by applying heat to the liquid, and the first liquid flow path The free end is arranged between the flow path and the bubble generation region, has a free end on the discharge port side, and the free end is set on the first liquid flow path side based on the pressure generated by the generation of the bubble in the bubble generation region. And a movable member that guides the pressure to the discharge port side of the first liquid flow path, wherein the first common liquid chamber is in a stationary state relative to the first liquid flow path. A liquid ejection head that is higher in the direction perpendicular to the surface including the movable member, the fulcrum of the movable member is in the first common liquid chamber, and the free end in the stationary state is in the first liquid flow path. .

Alternatively, a plurality of ejection ports for ejecting liquid, a plurality of grooves for forming a plurality of first liquid flow paths that directly communicate with each ejection port, and a plurality of the plurality of grooves. A grooved member integrally having a concave portion forming a first common liquid chamber for supplying a liquid to one liquid flow path, and a plurality of members for generating bubbles in the liquid by applying heat to the liquid The heating element is disposed between the element substrate on which the heating element is disposed, the grooved member and the element substrate, and forms a part of the wall of the second liquid flow path corresponding to the heating element. And a separation wall having a movable member that is displaced toward the first liquid flow path side by a pressure based on the generation of the bubbles at a position facing to the first common liquid chamber, The liquid is higher than the first liquid flow path in the direction perpendicular to the surface including the stationary movable member, Fulcrum of wood is, the first present in the common liquid chamber, the free end of the stationary state, the liquid ejection head that exists in the first liquid flow path.

According to the liquid discharge head of the present invention based on the extremely novel discharge principle as described above, the fulcrum of the movable member is provided in the first common liquid chamber, so that the discharge when the movable member is displaced. Since the resistance from the ceiling wall of the flow path can be minimized, the discharge efficiency can be further improved.

Further, since the first liquid flow path is short and the flow path resistance of the discharge liquid is small, it is possible to discharge the high-viscosity recording liquid, which has been a problem particularly in refilling until now.

In particular, according to the configuration of the present invention with improved refill characteristics, responsiveness during continuous ejection, stable growth of bubbles, and stabilization of droplets are achieved, and high-speed recording by high-speed liquid ejection and high image quality are achieved. It was possible to record. Also,
Since the synergistic effect of the generated bubbles and the movable member displaced by the bubbles can be obtained, and the liquid in the vicinity of the discharge port can be efficiently discharged, the discharge efficiency can be improved as compared with the conventional bubble jet type discharge head. For example, in the most preferred embodiment of the present invention, a dramatic improvement in the discharge efficiency of twice or more could be achieved.

According to the characteristic structure of the present invention, it is possible to prevent non-ejection even when the apparatus is left for a long time at a low temperature or low humidity. There is also an advantage that it is possible to immediately return to a normal state by performing a slight recovery process.

Specifically, even under the long-term standing condition in which most of the conventional bubble jet type heads having 64 ejection ports are incapable of ejecting, the head of the present invention ejects less than about half the ejection ports. It just becomes. In addition, when these heads are recovered by preliminary ejection, it is necessary to perform thousands of preliminary ejections with the conventional head for each ejection port,
In the present invention, it was sufficient to perform the recovery with about 100 preliminary ejections. This means that the recovery time can be shortened, the loss of liquid due to recovery can be reduced, and the running cost can be significantly reduced.

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

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

The "downstream side" of the bubble itself is as follows.
It mainly represents a portion on the ejection port side of a bubble which is considered to directly act on ejection of a droplet. More specifically, with respect to the center of the bubble, the downstream side with respect to the flow direction and the structural direction,
Alternatively, it means bubbles generated in a region downstream of the area center of the heating element.

The term “substantially sealed” used in the description of the present invention refers to a state in which bubbles do not slip through gaps (slits) around the movable member before the movable member is displaced when the bubbles grow. Means

In the broad sense, the term "separation wall" as used in the present invention means a wall (which may include a movable member) interposed so as to separate a bubble generation region from a region directly communicating with the discharge port. In a narrow sense, it means that the flow path including the bubble generation area is separated from the liquid flow path that directly communicates with the discharge port, and mixing of the liquid in each area is prevented.

Further, the "comb tooth" in the present invention means a shape in which the fulcrum portion of the movable member is a common member and the front of the free end is open.

[0051]

【Example】

(Explanation of Principle) Hereinafter, the ejection principle applicable to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic sectional view of the liquid discharge head cut in the liquid flow path direction, and FIG. 2 shows a partially cutaway perspective view of the liquid discharge head.

The liquid discharge head shown in FIG. 1 serves as a discharge energy generating element for discharging a liquid, and has a heating element 2 (40 μm in this embodiment) for applying heat energy to the liquid.
A heating resistor having a shape of m × 105 μm) is provided on the element substrate 1, and a liquid flow path 10 is arranged on the element substrate corresponding to the heating element 2. The liquid flow path 10 is in communication with the ejection port 18 and also with the common liquid chamber 33 for supplying liquid to the plurality of liquid flow paths 10, and the amount of liquid commensurate with the liquid ejected from the ejection port. From the common liquid chamber 33.

On the element substrate of the liquid flow path 10, a plate-like movable member 31 facing the above-mentioned heating element 2 and made of an elastic material such as metal and having a flat portion is provided.
Are provided in a cantilever shape. One end of the movable member is fixed to a base (supporting member) 34 formed by patterning a photosensitive resin or the like on the wall of the liquid flow path 10 or the element substrate. Thus, the movable member is held and forms a fulcrum (fulcrum portion) 33.

The movable member 31 has a fulcrum (fulcrum portion; fixed end) 33 on the upstream side of a large flow flowing from the common liquid chamber 33 to the ejection port 18 side through the movable member 31 by the liquid ejection operation. It has a free end (free end portion) 32 on the downstream side with respect to 33, and is arranged at a position facing the heating element 2 at a distance of about 15 μm from the heating element so as to cover the heating element 2. There is. A space between the heating element and the movable member is a bubble generation area. Note that the types, shapes, and arrangements of the heating element and the movable member are not limited thereto, and may be any shape and arrangement that can control the growth of bubbles and the propagation of pressure as described later. Note that the above-described liquid flow path 10
In order to explain the flow of the liquid to be discussed later, the movable member 31
The portion directly connected to the discharge port 18 with the boundary as the first liquid flow path 14 is divided into two areas of the bubble generation area 11 and the second liquid flow path 16 having the liquid supply path 12 for explanation. I do.

The movable member 31 is generated by causing the heating element 2 to generate heat.
Heat is applied to the liquid in the bubble generation region 11 between the heating element 2 and the heating element 2 to generate bubbles in the liquid based on the film boiling phenomenon as described in US Pat. No. 4,723,129. The pressure based on the generation of the air bubbles and the air bubbles act preferentially on the movable member, and the movable member 31 opens largely toward the discharge port around the fulcrum 33 as shown in FIG. 1 (b), (c) or FIG. To be displaced. Depending on the displacement or the displaced state of the movable member 31, the propagation of pressure based on the generation of bubbles and the growth of the bubbles themselves are guided to the ejection port side.

Here, one of the basic ejection principles applied to the present invention will be described. One of the most important principles in the present invention is that a movable member arranged to face a bubble is a first member in a steady state based on the pressure of the bubble or the bubble itself.
Is displaced from the position (1) to the second position, which is the position after the displacement, and the pressure accompanying the generation of bubbles and the bubbles themselves are guided by the displaceable movable member 31 to the downstream side where the discharge port 18 is arranged.

This principle will be described in more detail by comparing FIG. 3 schematically showing a conventional liquid flow path structure using no movable member with FIG. 4 of the present invention. Here, the propagation direction of the pressure toward the discharge port is VA, and the propagation direction of the pressure toward the upstream side is VB.
As shown.

In the conventional head as shown in FIG. 3, there is no structure for controlling the propagation direction of pressure by the generated bubbles 40. Therefore, the pressure propagation direction of the bubble 40 is V1 to
As in V8, it was perpendicular to the surface of the bubble and was oriented in various directions. Among them, VA which has the most influence on liquid ejection
The component having the pressure propagation direction in the direction is the direction component of the pressure propagation of V1 to V4, that is, the part closer to the discharge port than the position of almost half of the bubble, and directly affects the liquid discharge efficiency, liquid discharge force, discharge speed, etc. It is an important part to contribute. V1 is the ejection direction V
Since it is closest to the direction of A, it works efficiently, and on the contrary, V4 has a relatively small direction component toward VA.

On the other hand, in the case of the present invention shown in FIG. 4, the pressure propagation directions V1 to V4 of the bubbles in which the movable member 31 faces various directions as in the case of FIG. It is guided to the discharge port side) and is converted into the VA pressure propagation direction, whereby the pressure of the bubble 40 directly and efficiently contributes to the discharge. Then, the bubble growth direction itself is guided in the downstream direction similarly to the pressure propagation directions V1 to V4, and the bubble grows more downstream than upstream. As described above, by controlling the growth direction itself of the bubble by the movable member and controlling the pressure propagation direction of the bubble, it is possible to achieve a fundamental improvement in the discharge efficiency, the discharge force, the discharge speed, and the like.

Next, returning to FIG. 1, the ejection operation of the above-described liquid ejection head will be described in detail.

FIG. 1 (a) shows a state before energy such as electric energy is applied to the heat generating element 2, that is, a state before the heat generating element generates heat. What is important here is that the movable member 31 is provided at a position facing at least a downstream portion of the bubble generated by the heat generated by the heating element. In other words, on the liquid flow path structure, at least downstream of the area center 3 of the heating element (from a line passing through the area center 3 of the heating element and orthogonal to the length direction of the flow path, so that the downstream side of the bubble acts on the movable member. The movable member 31 is arranged to the position (downstream).

In FIG. 1B, electric energy or the like is applied to the heating element 2 to heat the heating element 2, and the generated heat heats a part of the liquid filling the bubble generating region 11 to cause film boiling. This is a state in which accompanying bubbles are generated.

At this time, the movable member 31 is displaced from the first position to the second position by the pressure based on the generation of the bubble 40 so as to guide the pressure propagation direction of the bubble 40 toward the discharge port. What is important here is that, as described above, the free end 32 of the movable member 31 is arranged on the downstream side (discharge port side), and the fulcrum 33 is arranged on the upstream side (common liquid chamber side). That is, at least a part of the movable member faces a downstream portion of the heating element, that is, a downstream portion of the bubble.

FIG. 1C shows a state in which the bubbles 40 have further grown, but the movable member 31 is further displaced in accordance with the pressure caused by the generation of the bubbles 40. The generated bubble grows greatly downstream from the upstream and grows greatly beyond the first position (dotted line position) of the movable member. Thus, bubble 4
When the movable member 31 is gradually displaced in accordance with the growth of 0, the pressure propagation direction of the bubble 40 and the direction in which the deposition is easily moved, that is, the growth direction of the bubble to the free end side is uniformly directed to the discharge port. It can be considered that being able to change the height also enhances the discharge efficiency. The movable member rarely hinders the transmission of bubbles or foaming pressure toward the discharge port, and efficiently controls the direction of pressure propagation and the direction of bubble growth according to the magnitude of the propagating pressure. Can be.

FIG. 1D shows a state in which the bubble 40 contracts and disappears after the film boiling described above due to a decrease in the bubble internal pressure.

The movable member 31 which has been displaced to the second position
Is the initial position (first position) in FIG. 1A due to the negative pressure due to the contraction of the bubble and the restoring force due to the spring property of the movable member itself.
Return to. Further, at the time of defoaming, V _{D1 of} the flow from the upstream side (B), that is, the common liquid chamber side, in order to supplement the contracted volume of the bubbles in the bubble generation region 11 and to supplement the volume of the discharged liquid, The liquid flows in like V _D2 and like the flow Vc from the ejection port side.

The operation of the movable member and the liquid ejecting operation associated with the generation of bubbles have been described above. The liquid refilling in the liquid ejecting head applicable to the present invention will be described in detail below.

After the state shown in FIG. 1 (c), when the bubble 40 enters the defoaming process after reaching the maximum volume state, a volume of liquid that compensates for the defoamed volume is placed in the bubble generation region of the first liquid flow path 14. It flows in from the discharge port 18 side and the common liquid chamber side 13 of the second liquid flow path 16. In the conventional liquid flow path structure without the movable member 31, the amount of the liquid flowing from the discharge port side to the defoaming position and the amount of the liquid flowing from the common liquid chamber are the same as the part closer to the discharge port than the bubble generation region and the common liquid. Due to the magnitude of the flow resistance with the part close to the chamber (based on the flow path resistance and the inertia of the liquid).

Therefore, when the flow resistance on the side close to the ejection port is small, a large amount of liquid flows from the ejection port side to the defoaming position, and the retreat amount of the meniscus increases. In particular, as the flow resistance on the side close to the discharge port is reduced to increase the discharge efficiency in order to increase the discharge efficiency, the meniscus M at the time of defoaming becomes larger, the refill time becomes longer, and the refill time becomes longer, and high-speed printing is performed. Was to hinder.

On the other hand, since the movable member 31 is provided in this configuration, when the volume W of the bubble is W1 on the upper side and W2 on the side of the bubble generating region 11 with the first position of the movable member 31 as a boundary, at the time of defoaming. When the movable member returns to the original position, the retraction of the meniscus is stopped, and the liquid supply of the remaining volume of W2 is mainly performed by the liquid supply from the flow V _D2 of the second flow path 16. Thus, while the amount corresponding to about half of the volume of the bubble W has conventionally been the meniscus retraction amount, it has become possible to suppress the meniscus retreat amount to a smaller amount, which is about half of W1.

Further, the liquid supply for the volume of W2 is forced along the surface of the movable member 31 on the heating element side, mainly from the upstream side (V _D2 ) of the second liquid flow path, by utilizing the pressure at the time of defoaming. Since it can be done automatically, a faster refill could be realized.

What is characteristic here is that when refilling using the pressure at the time of defoaming with a conventional head, the vibration of the meniscus becomes large, leading to deterioration of image quality. In the high-speed refill, the movable member suppresses the flow of the liquid between the region of the first liquid flow path 14 on the ejection port side and the bubble generation region 11 on the ejection port side, so that the vibration of the meniscus can be extremely reduced. Is.

As described above, the above-described configuration applied to the present invention is performed at high speed by the forced refill of the second liquid flow path 16 into the foaming region through the liquid supply path 12 and the suppression of the meniscus retreat and vibration described above. By achieving refill, stable ejection, high-speed repetitive ejection, and improvement in image quality and high-speed recording can be realized when used in the field of recording.

The above-mentioned configuration applied to the present invention further has the following effective functions. That is, the propagation of the pressure to the upstream side (back wave) due to the generation of bubbles is suppressed. Among the bubbles generated on the heating element 2, the pressure due to the bubbles on the common liquid chamber 33 side (upstream side) is as follows:
Many of them had a force (back wave) to push the liquid back toward the upstream side. This back wave caused the pressure on the upstream side, the amount of liquid movement due thereto, and the inertia force accompanying the liquid movement, which reduced the refill of the liquid into the liquid flow path and hindered high-speed driving. . In this configuration, the refill supply is further improved by first suppressing these effects on the upstream side by the movable member 31.

Next, further characteristic structures and effects will be described below.

The second liquid flow passage 16 has a liquid supply passage 12 upstream of the heating element 2 and having an inner wall which is connected to the heating element 2 substantially flat (the surface of the heating element is not largely depressed). In such a case, the bubble generation region 11 and the heating element 2
Supply of the liquid to the surface of, along the side surface closer to the bubble generation region 11 of the movable member 31 is performed as V _D2. Therefore, stagnation of the liquid on the surface of the heating element 2 is suppressed, and deposition of gas dissolved in the liquid and so-called residual air bubbles that cannot be defoamed are easily removed. The heat storage does not become too high. Therefore, more stable generation of bubbles can be repeated at high speed. In the present embodiment, the liquid supply path 12 having a substantially flat inner wall has been described. However, the present invention is not limited to this. Any liquid supply path that has a gentle inner wall that is smoothly connected to the surface of the heating element. Any shape that does not cause stagnation of the liquid on the heating element or large turbulence in the supply of the liquid may be used.

In some cases, the liquid is supplied to the bubble generating region from V _D1 via the side portion (slit 35) of the movable member. However, in order to more effectively guide the pressure at the time of bubble generation to the discharge port, a large movable member is used so as to cover the entire bubble generation region (cover the heating element surface) as shown in FIG. by return to the position, in the case of forms, such as the flow resistance of the liquid becomes large between the region near the the bubble generation region 11 discharge ports of the first liquid flow path 14, the bubble generating area 11 from the aforementioned V _D1 Incoming liquid flow is impeded. However, in the head structure of the present invention, since there is the flow V _D2 for supplying the liquid to the bubble generation region, the liquid supply performance is very high, and the movable member 31 covers the bubble generation region 11 for ejection. Even if the structure is designed to improve efficiency, the liquid supply performance is not deteriorated.

As for the positions of the free end 32 and the fulcrum 33 of the movable member 31, the free end is relatively downstream of the fulcrum as shown in FIG. 5, for example. With such a configuration, it is possible to efficiently realize functions and effects such as guiding the pressure propagation direction and growth direction of bubbles to the ejection port side during the above-described foaming. Further, this positional relationship achieves not only a function and an effect on the ejection, but also an effect that the flow resistance to the liquid flowing through the liquid flow path 10 can be reduced and the refill can be performed at a high speed even when the liquid is supplied. As shown in FIG. 5, when the meniscus M retracted by the discharge returns to the discharge port 18 by capillary force or when liquid is supplied to the defoaming, the liquid flow path 10 (the first liquid (Including the flow path 14 and the second liquid flow path 16).
This is because the free end and the fulcrum 33 are arranged so as not to go against each other.

Supplementally, in FIG. 1 of this configuration, as described above, the free end 32 of the movable member 31 divides the heating element 2 into the upstream area and the downstream area by the area center 3 (heating element). Of the heating element 2 so as to face a position downstream of a line passing through the center (center) of the area and orthogonal to the length direction of the liquid flow path. As a result, the area center position 3 of the heating element
The movable member 31 receives a pressure or a bubble that greatly contributes to the discharge of the liquid generated on the downstream side, and the pressure and the bubble can be guided to the discharge port side, thereby fundamentally improving the discharge efficiency and the discharge force. Can be.

In addition, many effects are obtained by utilizing the upstream side of the bubbles.

In addition, in this configuration, it is considered that the free end of the movable member 31 makes an instantaneous mechanical displacement, which effectively contributes to the ejection of the liquid. (Embodiment 1) Also in this embodiment, the principle of discharging the main liquid is the same as that described above. In addition, in the following embodiments (embodiments and other embodiments), the first liquid passage 14 and the second liquid passage 16 are described using a head divided by a separation wall 30 as described below. However, the present invention is not limited to this, and can be similarly applied to the head described in the above description of the principle.

The structure of this embodiment further has the following effective functions. That is, the flow resistance of the first liquid flow path 14 is minimized to achieve high-speed refile. In the present embodiment, as described above, the movable member 31 can direct the diverging pressure to the discharge port side, so that the first liquid flow path 14 is displaced to at least the second position. It suffices that the movable member 31 exists only on the discharge port side with respect to the free end. Further, with such a configuration, when the movable member 31 is displaced to the second position, the repulsive force received from the first liquid channel ceiling can be reduced.

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

FIG. 7 shows the influence of the ceiling of the first liquid flow path 14 on the displacement of the movable member 31. (A)
When the movable member 31 is displaced to the second position and the first liquid flow path 14 is located on the downstream side from the free end side, (b) is
The case where the first liquid flow path 14 is located upstream of the fulcrum 33 of the movable member 31 is shown. When the movable member 31 is displaced, it receives a repulsive force in a direction opposite to the direction in which it is displaced from the common liquid chamber 13 or the ceiling of the first liquid flow passage 14. Therefore, it is preferable that the first liquid flow path 14 is only on the downstream side of the free end position when the movable member 31 is displaced to the second position, as in the structure (a).

FIGS. 8 to 12 show examples of the movable member 31, the first liquid flow path 14 and the first common liquid chamber 13,
Since (a) shows the positional relationship between the movable member 31, the first liquid flow path 14 and the column 52 or the lateral wall 53 that fixes the fulcrum 33 of the movable member 31, the movable member 31 is viewed from the first liquid flow path side. 3B is a cross-sectional view of the nozzle, and FIG. 6B is a cross-sectional view of the nozzle in order to show the shape of the horizontal wall 53 of the first liquid flow path 14.

In FIG. 8, the first common liquid chamber 13 is located upstream of the free end position when the movable member 31 is displaced to the second position.
4 shows a nozzle structure having a column 52 that fixes the fulcrum 33 of the movable member 31.

With such a structure, when the movable member 31 is displaced, the repulsive force from the ceiling is so small that it can be ignored, so that the foaming power can be more efficiently converted into the ejection force. Since the fulcrum 33 of the movable member 31 exists in the first common liquid chamber 33 and may be influenced by the adjacent movable member 31 depending on the material of the movable member 31, the movable member 31 as in the present embodiment. It is preferable to fix the fulcrum 33 of.

FIG. 9 shows an example in which the first liquid flow path 14 is further upstream than in the previous embodiment. In this case, the fulcrum 33 of the movable member 31 is not fixed, but like the present embodiment, the fulcrum 33 of the movable member 31 is replaced with the first common liquid chamber 33.
Even if it is present in the inside, it exerts a sufficient effect to improve refill and discharge efficiency. It is also effective in the liquid ejection head using the comb-shaped movable member shown in FIG. 13 in which the foaming liquid and the ejection liquid are the same liquid.

FIG. 10 shows that the ceiling of the first liquid flow path 14 is higher on the upstream side than the position of the free end where the movable member 31 is displaced to the second position, and the first liquid flow path lateral wall between the adjacent nozzles. 53 is
A nozzle structure having a height up to a straight line connecting the free end and the fulcrum 33 when the movable member 31 is maximally displaced is shown. With such a structure, bubbles extending in the first liquid flow path 14 are Since it has the effect of preventing lateral escape, it is possible to more efficiently convert the foaming power into the ejection force.

FIG. 11 shows that the first liquid flow path lateral wall 53 of the first liquid flow path 14 is different from the previous embodiment in that the fulcrum 3 of the movable member 31 is a fulcrum.
This is an example having up to three. As in the present embodiment, even if the ceiling of the first liquid flow path 14 is raised, as in the previous embodiment, the repulsive force of the movable member 31 is reduced, the refill is improved, and the lateral escape of bubbles is prevented. To do.

FIG. 12 is an example of a nozzle structure in which the free end exists in the first common liquid chamber 33 when the movable member 31 is maximally displaced. As in this embodiment, at least when stationary,
Even if only the structure in which the free end of the movable member is present in the first liquid flow path is provided, a sufficient effect can be exerted for improving refill and discharging efficiency. (Other Embodiments) The embodiments of the essential parts of the liquid ejection head and the liquid ejection method of the present invention have been described above. The embodiments that can be preferably applied to these embodiments will be described below with reference to the drawings. To do. However, in the following description, there may be a case where one of the examples of the one-flow channel type and the example of the two-channel type described above is taken up and explained, but it is applicable to both examples unless otherwise stated. is there.

The operation of the liquid ejection head of this embodiment will be described with reference to FIG.

When driving the head, the same aqueous ink was used as the ejection liquid supplied to the first liquid flow path 14 and the bubbling liquid supplied to the second liquid flow path 16. The heat generated by the heating element 2 acts on the bubbling liquid in the bubble generation region 11 of the second liquid flow path 16, so that the bubbling liquid is described in USP 4,723,129 in the same manner as described in the previous embodiment. The bubbles 40 are generated based on the film boiling phenomenon as described above.

In the present embodiment, there is no escape of the foaming pressure from the three sides except the upstream side of the bubble generating region 11, so the pressure due to the bubble generation is on the side of the movable member 31 disposed in the discharge pressure generating portion. 14 (b) from the state of FIG. 14 (a) in which the movable member 31 propagates in a concentrated manner and grows with bubbles.
Is displaced to the first liquid flow path 14 side.

Further, similar to the previous embodiment, when the movable member 31 is displaced due to the generation of bubbles, resistance acts on the movable member 31 in the opposite direction to the displacement direction.
As in the case where the fulcrum of the movable member 31 is inside the first liquid flow path 14 as described above, the resistance is sufficiently small. In addition, since the refilling property is good, it is possible to eject even a liquid having a particularly high viscosity.

Due to the operation of the movable member 31, the first liquid flow passage 14 and the second liquid flow passage 16 are largely communicated with each other, and the pressure due to the generation of bubbles causes the pressure toward the discharge port side of the first liquid flow passage 14 (A Direction) mainly transmitted. The liquid is discharged from the discharge port by the propagation of the pressure and the mechanical displacement of the movable member 31 as described above.

Next, as the bubbles shrink, the movable member 3
1 returns to the position shown in FIG.
In 4, the amount of the discharged liquid corresponding to the amount of the discharged liquid is supplied from the upstream side. Also in this embodiment, since the supply of the discharge liquid is in the direction in which the movable member 31 is closed similarly to the above-described embodiment, the refill of the discharge liquid is performed by the movable member 31.
There is no hindrance.

<Movable Member and Separation Wall> FIG. 15 shows another shape of the movable member 31, 35 is a slit provided in the separation wall, and the slit forms the movable member 31. . (A) is a rectangular shape, (b) is a shape where the fulcrum side is narrower and the movable member is easy to operate, and (c) is a shape where the fulcrum side is wider and the movable member is wider. This is a shape that improves the durability of the device.
As a shape having good operability and durability, FIG.
As shown in (a), it is desirable that the width on the fulcrum side is narrowed in an arc shape, but the shape of the movable member is a shape that can easily operate without entering the second liquid flow path side. ,
Any shape having excellent durability may be used.

In the previous embodiment, the plate-shaped movable member 31
The separating wall 30 having the movable member is made of nickel having a thickness of 5 μm. However, the material forming the movable member and the separating wall is not limited to this, and is resistant to the foaming liquid and the discharge liquid. It is sufficient that the movable member has elasticity so that the movable member can operate favorably and a fine slit can be formed.

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

As the material of the separating wall 30, polyethylene, polypropylene, polyamide, polyethylene terephthalate, melamine resin, phenol resin, epoxy resin, polybutadiene, polyurethane, polyether ether ketone, polyether sulfone, polyarylate, polyimide, polysulfone, Liquid crystal polymer (LC
P) and other resins having good heat resistance, solvent resistance, and moldability represented by engineering plastics in recent years, and compounds thereof, or metals, alloys such as silicon dioxide, silicon nitride, nickel, gold, and stainless steel; The compound,
Alternatively, those coated with titanium or gold on the surface are desirable.

The thickness of the separation wall 30 may be determined in consideration of its material and shape from the viewpoint that the strength as the separation wall 30 can be achieved and the movable member 31 works well. , 0.5 μm to 10 μm is desirable.

The width of the slit 35 for forming the movable member 31 is set to 2 μm in this embodiment. However, if the bubbling liquid and the discharge liquid are different liquids, and if it is desired to prevent the mixture of both liquids, the slit 35 is formed. The width may be set so as to form a meniscus between the two liquids to suppress the flow of the respective liquids. For example, when a liquid of about 2 cP (centipoise) is used as the foaming liquid and a liquid of 100 cP or more is used as the discharge liquid, the liquid mixture can be prevented even with a slit of about 5 μm, but it is preferable that the slit be 3 μm or less. .

As the movable member 31 in the present invention, μm
It is intended for a thickness on the order of (tμm), and a movable member having a thickness on the order of cm is not intended. For a movable member having a thickness on the order of μm, when considering a slit width (Wμm) on the order of μm, it is desirable to take into account some manufacturing variations.

When the thickness of the member facing the free end and / or the side end of the movable member 31 forming the slit is equal to the thickness of the movable member (FIG. 14 etc.), the relation between the slit width and the thickness may be varied. Considering this, the mixed liquid of the foaming liquid and the discharge liquid can be stably suppressed by setting the range as follows. Although this is a limited condition, as a design point of view, when a high-viscosity ink (5 cp, 10 cp, etc.) is used for a foaming liquid having a viscosity of 3 cp or less, W / t ≦ 1.
Is satisfied, the mixing of the two liquids can be suppressed for a long time.

The slit providing the "substantially closed state" of the present invention is more certain if it is on the order of several μm.

As described above, when the foaming liquid and the discharge liquid are functionally separated, the movable member serves as a substantial partitioning member for these. It can be seen that the foaming liquid mixes slightly with the discharge liquid when the movable member moves with the generation of bubbles. Considering that the ejection liquid for forming an image generally has a coloring material concentration of about 3% to 5% in the case of inkjet recording, this foaming liquid is in a range of 20% or less with respect to the ejection droplets. Even if it is contained in, it does not cause a large concentration change. Therefore, the present invention includes such a mixed liquid as a mixture of a foaming liquid and an ejected liquid such that the amount thereof is 20% or less of the ejected liquid droplets.

In the implementation of the above configuration example, even if the viscosity is changed, the upper limit is 15% of the mixture of the foaming liquid and 5 cps.
In the following foaming liquid, this mixing ratio has an upper limit of about 10%, depending on the driving frequency.

In particular, as the viscosity of the discharge liquid is set to 20 cps or less, this mixed liquid can be reduced (for example, 5% or less).

Next, the positional relationship between the heating element and the movable member in this head will be described with reference to the drawings. However,
The shapes, dimensions, and numbers of the movable member and the heating element are not limited to the following. By the optimal arrangement of the heating element and the movable member, the pressure at the time of foaming by the heating element can be effectively used as the discharge pressure.

By applying energy such as heat to the ink, a state change accompanied by a sharp volume change (generation of bubbles) is caused in the ink, and the action force based on this state change ejects the ink from the ejection port. In a conventional technique of an ink jet recording method, which is a so-called bubble jet recording method, in which an image is formed by adhering a recording medium onto a recording medium, FIG.
As shown in FIG. 6, although the heating element area and the ink discharge amount are in a proportional relationship, it can be seen that there is a non-foaming effective region S that does not contribute to ink discharge. 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.

Therefore, in order to effectively use the foaming pressure, it is effective to dispose the movable member such that the area directly above the foaming effective area of about 4 μm or more from the periphery of the heating element is covered with the movable area of the movable member. Can be said to be target. In the present embodiment, the effective foaming area is set at about 4 μm or more inside the periphery of the heating element. However, the present invention is not limited to this, depending on the type and forming method of the heating element.

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

17A and 17B are vertical sectional views of the liquid discharge head of the present invention. FIG. 17A shows a head having a protective film which will be described later, and FIG. 17B shows a liquid ejecting head having no protective film.

The second liquid flow path 16 and the separation wall 3 are provided on the element substrate 1.
0, a first liquid flow path 14, and a grooved member 50 provided with grooves forming the first liquid flow path.

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

In particular, pressure and shock waves generated at the time of bubble generation and defoaming are extremely strong, and the durability of a hard and brittle oxide film is remarkably reduced. Therefore, tantalum (Ta) which is a metal material is used.
Are used as the anti-cavitation layer 102.

Further, depending on the combination of the liquid, the liquid flow path structure, and the resistance material, the structure in which the protective layer 103 is not necessary for the resistance layer 102 may be used, and an example thereof is shown in FIG. 17 (b).
Examples of the material of the resistance layer 105 that does not require the protective layer 103 include iridium-tantalum-aluminum alloy.

As described above, the structure of the heating element in each of the above-described embodiments may be only the resistance layer (heat generating portion) between the electrodes described above, or may include a protective layer for protecting the resistance layer.

In the present embodiment, the heating element having the heating portion composed of the resistance layer that generates heat in response to the electric signal is used, but the heating element is not limited to this, and is sufficient to eject the ejection liquid. Any bubbles can be used as long as they generate bubbles in the foaming 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 unit that generates heat by receiving a high frequency may be used as the heat generating unit.

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

Further, in order to drive the heat generating portion of the electrothermal converter provided on the element substrate 1 as described above and eject the liquid, the resistance layer 105 is connected to the resistance layer 105 via the wiring electrode 104 as shown in FIG. A rectangular pulse as shown by is applied to rapidly generate heat in the resistance layer 105 between the wiring electrodes. In the head of each of the above-described embodiments, the 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 of 6 kHz, and the liquid ink is discharged from the ejection port by the above-described operation. Discharged. 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.

<Discharge Liquid, Foaming Liquid> As described in the above embodiments, in the present invention, due to the structure having the movable member as described above, the discharge force and the discharge efficiency are higher than those of the conventional liquid discharge head. The liquid can be ejected at high speed. In the present embodiment, when the same liquid is used for the foaming liquid and the discharge liquid, the deposit is not easily generated on the heating element by heating without being deteriorated by the heat applied from the heating element, and vaporized by heat. Various liquids can be used as long as they can change the reversible state of condensation and do not deteriorate the liquid flow path, the movable member, the separation wall, and the like.

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

On the other hand, in the case of using the head having the two-passage structure of the present invention and making the discharge liquid and the foaming liquid different liquids, the liquid having the above-mentioned properties may be used as the foaming liquid. , Methanol, ethanol, n-propanol, isopropanol, n-hexane, n-heptane, n-octane, toluene, xylene, methylene dichloride, trichlene, Freon TF, Freon BF, ethyl ether, dioxane, cyclohexane, methyl acetate, acetic acid ethyl,
Examples include acetone, methyl ethyl ketone, water, and the like, and mixtures thereof.

As the discharge liquid, various liquids can be used regardless of the presence or absence of foaming property and the thermal property. In addition, liquids having low foaming properties, liquids which are easily deteriorated or deteriorated by heat, high-viscosity liquids, and the like, which have been difficult to discharge conventionally, can be used.

However, as the properties of the discharge liquid, the discharge liquid itself,
Alternatively, it is desirable that the liquid is not a liquid that hinders ejection, foaming, operation of the movable member, or the like due to a reaction with the foaming liquid.

High-viscosity ink or the like can also be used as the ejection liquid for recording. As other discharge liquids, liquids such as medicines and perfumes that are vulnerable to heat can be used.

In the present invention, recording was performed by using an ink having the following composition as a recording liquid that can be used as both the discharge liquid and the foaming liquid. As a result, the droplet landing accuracy is improved and a very good recorded image can be obtained.

Composition of Dye Ink (Viscosity 2 cP) (C-1. Food Black 2) Dye 3% by weight Diethylene glycol 10% by weight Thiodiglycol 5% by weight Ethanol 5% by weight Water 77% by weight Recording was performed by ejecting a combination of liquids having the following compositions. As a result, a liquid having a very high viscosity of 150 cP as well as a liquid having a viscosity of 10 cP, which was difficult with a conventional head, could be satisfactorily ejected, and a high-quality recorded matter could be obtained.

Composition of foaming liquid 1 Ethanol 40% by weight Water 60% by weight Composition of foaming liquid 2 Water 100% by weight Composition of foaming liquid 3 Isopyr alcohol 10% by weight Water 90% by weight Discharge liquid 1 Pigment ink (viscosity 15 cP) Composition Carbon black 5% by weight Styrene-acrylic acid-acrylic acid ester copolymer 1% by weight (acid value 140, weight average molecular weight 8000) Monoethanolamine 0.25% by weight Glycerin 69% by weight Thiglycol 5% by weight Ethanol 3% by weight % Water 16.75% by weight Composition of ejection liquid 2 (viscosity 55 cP) Polyethylene glycol 200 100% by weight Composition of ejection liquid 3 (viscosity 55 cP) Polyethylene glycol 600 100% by weight By the way, it is said that conventional ejection is difficult. In case of liquid, the discharge speed is low. Ejection direction of the variation is promoted poor landing accuracy of the dot on the recording paper, but also cause the discharge amount of variation by the discharge unstable,
Due to these things, it was difficult to obtain a high-quality image. 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.

<Head Structure with Two-Channel Structure> FIG. 19 is an exploded perspective view showing the overall structure of the head with two-channel structure in the liquid discharge head of the present invention.

The element substrate 1 described above is arranged on a support 70 made of aluminum or the like. A wall of the second liquid flow path 16 and a wall of the second common liquid chamber 17 are provided on this, and a separation wall 30 having a movable member 31 is provided thereon. Furthermore, a plurality of grooves forming the first liquid flow path 14 on the separation wall 30, the first common liquid chamber 13, the first common liquid chamber 1
And a supply path 20 for supplying the first liquid to the third
Supply path 2 for supplying the second liquid to the common liquid chamber 17 of
The grooved member 50 provided with No. 1 is provided, and the liquid ejection head having two channels is configured by such a configuration.

<Liquid Ejecting Device> FIG. 20 shows a schematic structure of a liquid ejecting device equipped with the above-mentioned liquid ejecting head. In this embodiment, an ink discharge recording apparatus using ink as a discharge liquid will be described in particular. The carriage HC of the liquid ejecting apparatus includes a liquid tank unit 90 that stores ink.
The liquid ejection head unit 200 is mounted with a detachable head cartridge, and reciprocates in the width direction of the recording medium 150 such as recording paper conveyed by the recording medium conveying means.

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

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

FIG. 21 is a block diagram of the entire apparatus for operating the ink discharge recording to which the liquid discharge method and the liquid discharge head of the present invention are applied.

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

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

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

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

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

Needless to say, the present invention is also applicable to a side shooter type having a discharge port at a position facing the heater surface.

[0144]

As described above, the cantilever-shaped movable member that opens in the discharge direction by the pressure generated by the bubble generation is provided in the discharge force generation region, and the fulcrum of the movable member exists in the first common liquid chamber. By doing so, the pressure generated as described above can be efficiently directed to the ejection direction without interfering with the displacement of the movable member, and the influence of the back wave can be prevented, and the first liquid flow path can be prevented. Since the flow resistance can be minimized, it is possible to eject the liquid with high ejection efficiency and high ejection pressure while improving the refill of the ejected liquid. In particular, the first liquid flow path for discharging the liquid and the second liquid flow path for generating the bubbles are separated from each other, and the portion where foaming is performed is formed into a chamber having a supply path. The efficiency can be improved and the above effects can be further enhanced.

Further, according to the liquid discharge head of the present invention based on the novel discharge principle using the movable member as described above, it is possible to obtain a synergistic effect of the generated bubbles and the movable member displaced by the generated bubbles. Since the liquid in the vicinity of the outlet can be efficiently discharged, the discharge efficiency can be improved as compared with the conventional bubble jet type discharge head.

Further, according to the characteristic constitution of the present invention, it is possible to prevent the non-ejection even when left for a long time at low temperature and low humidity, and even if the non-ejection occurs, the preliminary ejection or suction is performed. There is also an advantage that it is possible to immediately return to the normal state by performing a little recovery process such as recovery. Along with this, the recovery time can be shortened, the loss of liquid due to the recovery can be reduced, and the running cost can be significantly reduced.

In particular, according to the structure of the present invention with improved refill characteristics, responsiveness during continuous ejection, stable growth of bubbles, and stabilization of droplets are achieved, and high-speed recording by high-speed liquid ejection and high image quality are achieved. It was possible to record.

Further, in the head having a two-channel structure, by using a liquid that easily foams or a liquid that hardly causes deposits (burns etc.) on the heating element as the foaming liquid, the degree of freedom in selecting the discharge liquid is increased. It was possible to satisfactorily discharge even liquids that were difficult to be discharged by the conventional bubble jet discharging method, such as high viscosity liquids that are more likely to be foamed and liquids that are more likely to produce a volume on the heating element.

Further, a liquid weak to heat could be discharged without adversely affecting the liquid.

Furthermore, since the liquid, which has a high viscosity and can be applied only by a method such as coating, can be applied to the recording medium in dot units, a high-quality recorded matter can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a liquid ejection head of the present invention.

FIG. 2 is a partially cutaway perspective view of the liquid ejection head of the present invention.

FIG. 3 is a schematic diagram showing pressure propagation from bubbles in a conventional head.

FIG. 4 is a schematic diagram showing pressure propagation from bubbles in the head of the present invention.

FIG. 5 is a schematic diagram for explaining a flow of a liquid according to the present invention.

FIG. 6 is a diagram for explaining a liquid flow path structure of a conventional liquid ejection head.

FIG. 7 is a schematic cross-sectional view showing the repulsive force received by the movable member in the liquid ejection head of the present invention from the ceiling of the liquid flow path.

FIG. 8 is a schematic cross-sectional view of a liquid ejection head according to an example of the present invention.

FIG. 9 is a schematic cross-sectional view of a liquid ejection head in an example of the present invention.

FIG. 10 is a schematic cross-sectional view of a liquid ejection head according to an example of the present invention.

FIG. 11 is a schematic cross-sectional view of a liquid ejection head according to an example of the present invention.

FIG. 12 is a schematic cross-sectional view of a liquid ejection head according to an example of the present invention.

FIG. 13 is a diagram for explaining a comb-shaped movable member.

FIG. 14 is a view for explaining the operation of the movable member.

FIG. 15 is a view for explaining another shape of the movable member.

FIG. 16 is a diagram illustrating a relationship between a heating element area and an ink ejection amount.

FIG. 17 is a vertical cross-sectional view of the liquid ejection head of the present invention.

FIG. 18 is a schematic diagram showing the shape of a drive pulse.

FIG. 19 is an exploded perspective view of a head according to the present invention.

FIG. 20 is a schematic configuration diagram of a liquid ejection device.

FIG. 21 is a device block diagram.

[Explanation of symbols]

 1 Element Substrate 2 Heating Element 3 Area Center 5 Wiring Electrode 10 Liquid Flow Path 11 Bubble Generation Area 12 Supply Path 13 First Common Liquid Chamber (Common Liquid Chamber) 14 First Liquid Flow Path 16 Second Liquid Flow Path 17 Second Common Liquid chamber 18 Discharge port 19 Constricted portion 20 First supply path 21 Second supply path 30 Separation wall 31 Movable member 32 Free end 33 Support point 34 Supporting member 35 Slit 40 Bubble 50 Groove member 51 Orifice plate 52 Pillar 53 First liquid flow Side wall 54 Liquid chamber 55 Valve

[Procedure amendment]

[Submission date] June 20, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 14

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Hiroyuki Ishinaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Yoshie Nakata 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non non corporation

Claims (61)

[Claims] 1. A discharge port for discharging a liquid, a bubble generation region for generating bubbles in the liquid, a bubble generation region disposed to face the bubble generation region, and a first position and the bubble generation region more than the first position. A movable member that can be displaced between a second position far from the region, and the movable member is moved from the first position to the second position by a pressure based on the generation of bubbles in the bubble generating unit. A liquid ejecting head that ejects liquid by displacing the movable member to a position and expanding the air bubbles to a larger extent downstream than in the direction toward the ejection port by the displacement of the movable member, wherein the first common liquid chamber comprises: The fulcrum of the movable member is higher than the first liquid flow path in the direction perpendicular to the plane including the stationary movable member,
A liquid ejecting head that is present in the first common liquid chamber and has a free end in a stationary state in the first liquid flow path. 2. The liquid ejection head according to claim 1, wherein the free end of the movable member comes into contact with the ceiling of the first liquid flow path when the movable member is maximally displaced. 3. The liquid ejection head according to claim 1, further comprising a first liquid flow path downstream of a free end when the movable member is maximally displaced. 4. The displacement of the movable member causes the downstream portion of the bubble to grow downstream from the movable member.
Liquid ejection head. 5. The liquid ejection head according to claim 1, wherein the movable member has a fulcrum and a free end located downstream of the fulcrum. 6. A discharge port for discharging a liquid, a heating element for generating bubbles in the liquid by applying heat to the liquid, and a liquid on the heating element from the upstream side of the heating element along the heating element. A liquid flow path having a supply path for supplying and a free end provided on the discharge port side facing the heating element, and displacing the free end based on the pressure generated by the generation of the bubbles And a movable member that guides the liquid to the ejection port side, wherein the first common liquid chamber is higher than the first liquid flow path in a direction perpendicular to a surface including the movable member in a stationary state, The fulcrum of the member is
A liquid ejecting head that is present in the first common liquid chamber and has a free end in a stationary state in the first liquid flow path. 7. The liquid ejection head according to claim 6, wherein when the movable member is maximally displaced, the free end of the movable member contacts the ceiling of the first liquid flow path. 8. The liquid ejection head according to claim 6, further comprising a first liquid flow path downstream from a free end when the movable member is maximally displaced. 9. A discharge port for discharging a liquid, a heating element for generating bubbles in the liquid by applying heat to the liquid, and a free end provided on the discharge port side facing the heating element. A movable member that displaces the free end based on the pressure caused by the generation of bubbles to guide the pressure to the discharge port side, and a liquid on the heating element from the upstream side along the surface of the movable member near the heating element. A first common liquid chamber, which is higher than a first liquid flow channel in a direction perpendicular to a surface including a movable member in a stationary state, and a fulcrum of the movable member. ,
A liquid ejecting head that is present in the first common liquid chamber and has a free end in a stationary state in the first liquid flow path. 10. The liquid ejection head according to claim 9, wherein the free end of the movable member comes into contact with the ceiling of the first liquid flow path when the movable member is maximally displaced. 11. The liquid ejection head according to claim 9, further comprising a first liquid flow path downstream from a free end when the movable member is maximally displaced. 12. A first liquid flow path communicating with a discharge port, a second liquid flow path having a bubble generation region for generating bubbles in the liquid by applying heat to the liquid, the first liquid flow path. Disposed between the flow path and the bubble generation region,
The discharge port side has a free end, and the free end is displaced toward the first liquid flow path side based on the pressure generated by the generation of bubbles in the bubble generation region to adjust the pressure to the first liquid flow path. And a movable member that is guided to the ejection port side of the first common liquid chamber, wherein the first common liquid chamber is higher than the first liquid flow path in a direction perpendicular to a surface including the stationary movable member, The fulcrum of
A liquid ejecting head that is present in the first common liquid chamber and has a free end in a stationary state in the first liquid flow path. 13. The liquid ejection head according to claim 12, wherein the free end of the movable member comes into contact with the ceiling of the first liquid flow path when the movable member is maximally displaced. 14. The liquid ejection head according to claim 12, further comprising a first liquid flow path downstream of a free end when the movable member is maximally displaced. 15. The liquid ejection head according to claim 1, wherein a heating element is provided at a position facing the movable member, and the bubble generation region is between the movable member and the heating element. 16. The liquid discharge head according to claim 6, wherein the free end of the movable member is located downstream of the center of the area of the heating element. 17. The liquid ejection head according to claim 15, further comprising a supply path for supplying a liquid onto the heating element from an upstream side of the heating element along the heating element. 18. The supply passage is a supply passage that has a substantially flat or gentle inner wall on the upstream side of the heating element, and supplies the liquid onto the heating element along the inner wall. The liquid discharge head according to claim 6, claim 9, or claim 17. 19. The liquid discharge head according to claim 6, wherein the bubbles are bubbles generated by film boiling of the liquid by heat generated by the heating element. 20. The movable member is plate-shaped,
The liquid ejection head according to claim 9 or 15. 21. The liquid ejection head according to claim 20, wherein all of the effective foaming regions of the heating element face the movable member. 22. The liquid ejection head according to claim 20, wherein the entire surface of the heating element faces the movable member. 23. The liquid ejection head according to claim 20, wherein the total area of the movable member is larger than the total area of the heating element. 24. The liquid ejection head according to claim 20, wherein a fulcrum of the movable member is arranged at a position deviating from directly above the heat generating element. 25. The liquid ejection head according to claim 20, wherein a free end of the movable member has a shape that is substantially orthogonal to a liquid flow path in which the heating element is arranged. 26. The liquid ejection head according to claim 20, wherein the free end of the movable member is arranged closer to the ejection port than the heating element. 27. The liquid discharge head according to claim 12, wherein the movable member is formed as a part of a separation wall arranged between the first flow path and the second flow path. 28. The liquid ejection head according to claim 27, wherein the separation wall is made of a metal material. 29. The liquid discharge head according to claim 28, wherein the metal material is nickel or gold. 30. The liquid ejection head according to claim 27, wherein the separation wall is made of resin. 31. The liquid ejection head according to claim 27, wherein the separation wall is made of ceramics. 32. A first common liquid chamber for supplying a first liquid to a plurality of the first liquid flow paths, and a second liquid to a plurality of the second liquid flow paths. 13. The liquid ejection head according to claim 12, wherein the second common liquid chamber is provided. 33. A plurality of ejection openings for ejecting liquid, a plurality of grooves for forming a plurality of first liquid flow paths that directly communicate with the respective ejection openings, and a plurality of the plurality of grooves. A grooved member integrally having a recess forming a first common liquid chamber for supplying liquid to one liquid flow path; and a plurality of members for generating bubbles in the liquid by applying heat to the liquid. An element substrate on which a heating element is arranged, is arranged between the grooved member and the element substrate, and constitutes a part of the wall of the second liquid flow path corresponding to the heating element, and the heating element And a separation wall having a movable member that is displaced toward the first liquid flow path side by a pressure based on the generation of the bubbles at a position facing the first common liquid chamber, The height of the movable member is higher than that of the first liquid flow path in the direction perpendicular to the surface including the stationary movable member. The fulcrum is
A liquid ejecting head that is present in the first common liquid chamber and has a free end in a stationary state in the first liquid flow path. 34. The liquid ejection head according to claim 33, wherein the free end of the movable member comes into contact with the ceiling of the first liquid flow path when the movable member is maximally displaced. 35. The liquid discharge head according to claim 33, wherein the liquid discharge head has a first liquid flow path downstream from a free end when the movable member is maximally displaced. 36. The liquid discharge head according to claim 33, wherein the free end of the movable member is located downstream of the center of the area of the heating element. 37. The grooved member has a first introduction path for introducing a liquid into the first common liquid chamber and a second introduction path for introducing a liquid into the second common liquid chamber. 34. The liquid ejection head according to claim 33, comprising: 38. The liquid ejection head according to claim 37, wherein the grooved member is provided with a plurality of the second introduction paths. 39. The liquid ejection head according to claim 37, wherein a ratio of a cross-sectional area of the first introduction passage and a cross-sectional area of the second introduction passage is proportional to a supply amount of each liquid. 40. The liquid ejection head according to claim 37, wherein the second introduction passage is an introduction passage that penetrates the separation wall and supplies the liquid to the second common liquid chamber. 41. The liquid ejection head according to claim 12, wherein the liquid supplied to the first liquid flow path and the liquid supplied to the second liquid flow path are the same liquid. 42. The liquid ejection head according to claim 12, wherein the liquid supplied to the first liquid flow path and the liquid supplied to the second liquid flow path are different liquids. 43. The liquid supplied to the second liquid flow path has at least one property of low viscosity, foaming property and thermal stability as compared with the liquid supplied to the first liquid flow path. The liquid ejection head according to claim 42, which is an excellent liquid. 44. The liquid discharge head according to claim 6, claim 9, claim 15 or claim 33, wherein the heating element is an electrothermal converter having a heating resistor that generates heat by receiving an electric signal. 45. The liquid discharge head according to claim 44, wherein the electrothermal converter has a protective film disposed on the heating resistor. 46. A wiring for transmitting an electric signal to the electrothermal converter and a functional element for selectively supplying an electric signal to the electrothermal converter are arranged on the element substrate. 44 liquid discharge heads. 47. The liquid ejection head according to claim 12, wherein the shape of the second liquid flow path in the portion where the bubble generating region or the heating element is arranged is a chamber shape. 48. The liquid ejection head according to claim 12, wherein the shape of the second flow path is a shape having a narrowed portion upstream of the bubble generation region or the heating element. 49. The liquid ejection head according to claim 6, wherein the distance from the surface of the heating element to the movable member is 30 μm or less. 50. The liquid ejection head according to claim 6, 9, 15, or 33, wherein the liquid ejected from the ejection port is ink. 51. A liquid discharge recording method using the liquid discharge head according to any one of claims 1 to 50. 52. A liquid ejecting apparatus comprising: the liquid ejecting head according to claim 1; and drive signal supplying means for supplying a drive signal for ejecting liquid from the liquid ejecting head. . 53. A liquid, comprising: the liquid ejection head according to claim 1; and a recording medium conveyance unit that conveys a recording medium that receives the liquid ejected from the liquid ejection head. Discharge device. 54. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting ink from the liquid ejecting head and adhering the ink to a recording paper. 55. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting the recording liquid from the liquid ejecting head and attaching the recording liquid to the cloth. 56. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting the recording liquid from the liquid ejecting head and adhering the recording liquid to plastic. 57. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting the recording liquid from the liquid ejecting head and adhering the recording liquid to a metal. 58. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting the recording liquid from the liquid ejecting head and attaching the recording liquid to the wood. 59. The liquid ejecting apparatus according to claim 52, wherein recording is performed by ejecting the recording liquid from the liquid ejecting head and adhering the recording liquid to the leather. 60. Color recording is performed by ejecting recording liquids of a plurality of colors from the liquid ejection head and adhering the recording liquids of a plurality of colors to a recording medium.
3. The liquid ejection device according to item 3. 61. The liquid ejecting apparatus according to claim 52, wherein a plurality of the ejection ports are arranged over the entire width of the recordable area of the recording medium.