JP2004098178A - Electrostatic actuator, droplet discharge head, ink jet recording apparatus, and liquid supply cartridge - Google Patents

Abstract

An object of the present invention is to prevent a deformable plate of a pressure correction chamber from adsorbing to a facing surface to perform a correction operation.
Kind Code: A1 A vibrating chamber having a vibrating plate as one surface, an electrode facing a vibrating plate with a predetermined gap therebetween, and a deformable plate which is a deformable portion that is displaced in accordance with an external pressure. As a surface, a pressure correction chamber 13 communicating with each vibration chamber 11, and a communication path 15 communicating between each vibration chamber 11 and communicating the pressure correction chamber 13. The deformable plate 14 has a pressure correction chamber 13 side. Micro projections 16 were formed on the surface.
[Selection diagram] Fig. 4

Description

[0001]
[Industrial applications]
The present invention relates to an electrostatic actuator, a droplet discharge head, an inkjet recording device, and a liquid supply cartridge.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-300421
[0003]
An inkjet head, which is a droplet ejection head used in an image recording apparatus such as a printer, a facsimile, and a copying apparatus or an inkjet recording apparatus used as an image forming apparatus, includes a single or a plurality of nozzle holes for discharging ink droplets, and the nozzle holes. Are provided with an ejection chamber (also referred to as an ink chamber, a liquid chamber, a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) and actuator means for generating pressure for pressurizing ink in the ejection chamber. The ink droplets are ejected from the nozzle holes by pressurizing the ink in the ejection chamber with the pressure generated by the actuator means.
[0004]
The droplet discharge head includes, for example, a droplet discharge head that discharges a liquid resist as droplets, a droplet discharge head that discharges a DNA sample as droplets, and the like. . The actuators that constitute the actuator portion of the droplet discharge head include optical devices such as a micropump and a micro light modulation device, micro switches (micro relays), multi-optical lens actuators (optical switches), micro flow meters, pressure It can also be applied to micro devices such as sensors.
[0005]
As an electrostatic actuator used for such a droplet discharge head, for example, a diaphragm and an electrode facing the diaphragm are arranged at a predetermined gap, and a drive voltage is applied between the diaphragm and the electrode. There has been known a device in which an electrostatic force is generated to deform and displace the diaphragm toward the electrode by the electrostatic force.
[0006]
A droplet discharge head using such an electrostatic actuator consumes less power than other methods. However, in order to further reduce power consumption, it is necessary to drive at a lower voltage. For low-voltage driving, it is necessary to reduce the distance between the electrode and the diaphragm (hereinafter, referred to as “gap length”) and reduce the thickness of the diaphragm.
[0007]
However, in such a case, although the driving voltage can be reduced, the gap length is narrow, and the rigidity is reduced by thinning the diaphragm, so that the space between the diaphragm and the electrode (hereinafter referred to as “vibration”). If water is present in the chamber, the vibrating plate once contacts the electrode due to liquid bridging force or hydrogen bonding force, and the vibrating plate enters a sticking state in contact with the electrode, and does not function as an actuator. For this reason, the vibration chamber must be configured so that fluid cannot enter from outside air.
[0008]
Therefore, it is conceivable that the vibration chamber is closed by sealing the opening of the vibration chamber with a sealing material. However, the entire space (hereinafter, referred to as “actuator chamber”) communicating with the vibration chamber is considered. If a configuration is adopted in which gas outside the head cannot enter or exit, a new problem arises.
[0009]
In other words, since the gas in the actuator chamber and the gas in the outside cannot move freely, if the pressure and temperature in the outside change, a difference is created between the pressure in the actuator and the outside, and the balance of the diaphragm depends on the magnitude of the difference in pressure. The position changes. For example, if the internal pressure in the actuator chamber is lower than the external pressure, the equilibrium position of the diaphragm approaches the electrode side, and if the internal pressure in the actuator chamber is higher than the external pressure, the equilibrium position of the diaphragm moves away from the electrode.
[0010]
As a result of the fluctuation of the equilibrium position of the vibration plate, the ejection amount and speed of the droplet ejected from the head change due to the pressure difference between the actuator chamber and the outside world. The characteristics cannot be maintained, and the image quality deteriorates.
[0011]
So, for example,
As disclosed in Patent Document 1, a displacement plate (deformable plate) that communicates with the atmosphere is provided in a substrate that forms a vibration plate called a cavity plate, and a pressure on the opposite side of the displacement plate to the atmosphere is provided. The compensation chamber (pressure compensation chamber) is connected to the vibration chamber, and the displaceable plate that forms one surface of the pressure compensation chamber has lower rigidity than the vibration plate, and can be displaced in accordance with the outside air pressure. Is known.
[0012]
By adopting such a configuration, even if the internal space of the head including the pressure correction chamber and the vibration chamber is configured to be air-tightly shielded from the atmosphere, when a pressure difference occurs between the vibration chamber and the outside, the vibration plate The displacement of the diaphragm can be suppressed by changing the equilibrium position of the deformable plate rather than changing the equilibrium position of the diaphragm.
[0013]
[Problems to be solved by the invention]
Mentioned above
The technique disclosed in Japanese Patent Application Laid-Open Publication No. H11-157,979 seeks to reduce the variation in the equilibrium position of the diaphragm only with the head configuration, although the head is slightly larger. A sufficient effect can be expected unlike the method in which the effect cannot be expected.
[0014]
However, even with such a configuration, a new problem arises because the rigidity of the deformable plate is sufficiently lower than the rigidity of the diaphragm. That is, when the distance between the deformable plate and its opposing surface is small, the pressure difference between the inside and outside of the head causes the deformable plate to easily contact the opposing surface. At this time, since the rigidity of the deformable plate is very low, once deformed, the deformable plate sticks to the facing surface due to van der Waals force acting on the facing surface and loses its function. Will be. Further, when there is adsorbed water and residual charge between the deformable plate and the facing surface, sticking is more likely to occur.
[0015]
On the other hand, if the distance between the deformable plate and its opposing surface is large, the deformable plate can be prevented from contacting the opposing surface, so that sticking can be prevented, but the volume of the pressure compensation chamber becomes large, Since the volume of the actuator chamber is greatly increased, the pressure difference between the actuator chamber and the outside air has a greater effect. As a result, a larger area is required for the space for the pressure compensation chamber, the head size increases, and the head cost increases. It will be higher.
[0016]
As described above, in the conventional electrostatic actuator or the ink jet head, the distance between the deformable plate and the facing surface is reduced and sticking is prevented without unnecessarily increasing the head size. However, there is a problem that stable operation characteristics cannot be obtained.
[0017]
The present invention has been made in view of the above points, and has a small electrostatic actuator capable of obtaining stable operation characteristics, a stable droplet discharge characteristic including the electrostatic actuator, and high-quality recording. It is an object of the present invention to provide a possible droplet discharge head, an ink jet recording apparatus equipped with the droplet discharge head, and a liquid supply cartridge integrating the droplet discharge head.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, the electrostatic actuator according to the present invention is provided with a deformable portion that can be displaced in accordance with an external pressure on at least one surface of a pressure correction chamber that communicates with a vibration chamber. This is a configuration having means for reducing the contact area when the possible portion comes into contact with the facing surface.
[0019]
Here, as a means for reducing the contact area, a configuration in which minute projections are formed on the pressure correction chamber side of the deformable portion, or a configuration in which minute projections are formed on a surface facing the deformable portion can be employed. The material of the microprojections is preferably silicon oxide or silicon nitride. Further, as a means for reducing the contact area, it is possible to adopt a configuration in which a surface of the pressure compensation chamber with which the deformable plate comes into contact is subjected to a surface roughening treatment for increasing the surface roughness.
[0020]
In the electrostatic actuator according to the present invention, at least one surface of the pressure correction chamber communicating with the vibration chamber is provided with a deformable portion that can be displaced in accordance with the outside air pressure, and the deformable portion of the pressure correction chamber comes into contact with the deformable portion. In this configuration, a hydrophobic film is formed on the surface.
[0021]
In the electrostatic actuator according to the present invention, at least one surface of the pressure correction chamber communicating with the vibration chamber is provided with a deformable portion that can be displaced in accordance with the outside air pressure, and the deformable portion of the pressure correction chamber comes into contact with the deformable portion. In this configuration, a conductive layer is formed on the surface.
[0022]
A droplet discharge head according to the present invention includes a nozzle for discharging droplets, a discharge chamber communicating with the nozzle, and an electrostatic actuator according to the present invention for pressurizing liquid in the discharge chamber. It is.
[0023]
An ink jet recording apparatus according to the present invention has the droplet discharge head according to the present invention mounted thereon as an ink jet head for discharging ink droplets.
[0024]
A liquid supply cartridge according to the present invention integrates the droplet discharge head according to the present invention for discharging liquid droplets and a liquid supply tank for supplying liquid to the droplet discharge head.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. An ink jet head according to a first embodiment of the droplet discharge head of the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the head, FIG. 2 is a cross-sectional view of the discharge chamber of the head along the longitudinal direction of the diaphragm, and FIG. 3 is a cross-section of the discharge part of the head along the lateral direction of the diaphragm. FIG. 4 is an explanatory cross-sectional view of the pressure correction unit of the head along the longitudinal direction of the deformable plate, and FIG. 5 is a plan explanatory view of the deformable plate of the head on the side of the pressure correction chamber.
[0026]
This head is of a side shooter type that discharges ink droplets from nozzle holes provided on the surface of the substrate, and has a laminated structure in which a flow path substrate 1, an electrode substrate 2, and a nozzle substrate 3 are joined. I have. By joining the flow path substrate 1 and the nozzle substrate 3, an ink is supplied to each of the ejection chambers 6 through a fluid resistance portion, which is not shown, and to each of the ejection chambers 6 (not shown) through which a plurality of nozzle holes 4 for ejecting ink droplets communicate. A common liquid chamber (common ink chamber) is formed. Note that an edge shooter type can also be used.
[0027]
Further, by joining the flow path substrate 1 and the electrode substrate 2, a vibration chamber 11 having the vibration plate 10 as one surface, an electrode 12 facing the vibration plate 10 with a predetermined gap therebetween, and A pressure correction chamber 13 communicating with each vibration chamber 11 and a communication passage 15 communicating between the vibration chambers 11 and the pressure correction chamber 13 are formed by using a deformable plate 14 that is a deformable portion that is displaced in response to one surface. are doing. The vibrating plate 10, the vibrating chamber 11, the electrode 12, the pressure correcting chamber 13, the deformable plate 14, and the communication path 15 constitute an electrostatic actuator according to the present invention.
[0028]
Here, the flow path substrate 1 is made of, for example, a silicon substrate, and a high-concentration p-type diffusion layer such as boron is formed and anisotropically etched with a KOH aqueous solution or the like to stop the high-concentration p-type diffusion layer from being etched. The diaphragm 10 is formed at the same time as the concave portion serving as the discharge chamber 6 is formed by using the layer forming technique. The flow path substrate 1 is formed with a concave portion having a deformable plate 14 at the bottom.
[0029]
The electrode substrate 2 has an insulating film 22 such as a silicon oxide film formed on a silicon substrate 21, a concave portion serving as the vibration chamber 11 is formed in the insulating film 22, and an electrode facing the diaphragm 10 is formed on the bottom surface of the concave portion. 12 are formed, and a concave portion serving as the pressure correction chamber 13 is formed. Although not shown, an insulating film such as a silicon oxide film is formed on at least the surface of the electrode 12 to prevent an electrical short circuit or the like due to contact with the vibration plate 11.
[0030]
After joining the flow path substrate 1 and the electrode substrate 2, the concave portion serving as the vibration chamber and the concave portion serving as the pressure correction chamber 13 are sealed with a sealant 25 to define the vibration chamber 11 and the pressure correction chamber 13. are doing.
[0031]
Here, the deformable plate 14 forming the wall surface of the pressure correction chamber 13 has a lower rigidity than the diaphragm 11 and can be deformed and displaced in accordance with a change in the outside air pressure. As shown in FIG. 5, the surface area of the deformable plate 14 on the pressure correction chamber 13 side has a contact area when the deformable plate 14 comes into contact with the wall surface 13 a of the pressure correction chamber 13. A large number of minute projections 16 as means for reducing the number of protrusions are formed.
[0032]
The nozzle substrate 3 uses, for example, a 50 μm-thick nickel substrate, and has a nozzle hole 4 on the surface of the nozzle substrate 3 so as to communicate with the discharge chamber 6. In addition, the nozzle substrate 3 can be formed of another metal material, a resin material, or a multilayer structure thereof.
[0033]
In this head thus configured, a pulse potential of 0 V to 40 V is applied to the electrode 12 by an oscillation circuit, and when the surface of the electrode 12 is positively charged, the head and the diaphragm 10 to which no pulse potential is applied are applied. The function of attracting static electricity acts, and the diaphragm 10 bends toward the electrode 12, and the diaphragm 10 contacts the electrode 12 via an insulating film (not shown).
[0034]
At this time, the ink is supplied from the common liquid chamber into the ejection chamber 6 through the fluid resistance part. Thereafter, by returning the potential to the electrode 12 to 0 V, the electrostatic force acting between the electrode 12 and the diaphragm 10 becomes zero, and the flexed diaphragm 10 returns to its original state with its own restoring force. At times, the pressure in the ejection chamber 6 rises rapidly, and ink droplets are ejected from the nozzle holes 4.
[0035]
Here, when the external pressure fluctuates and a pressure difference occurs between the vibration chamber 11 and the external pressure, the deformable plate 14 has a lower rigidity than the vibration plate 10 and can be deformed and displaced in accordance with the external pressure. When the pressure in the vibration chamber 11 becomes higher than the outside air pressure, the deformable plate 14 forming the wall surface of the pressure correction chamber 13 is deformed and displaced in a direction to enlarge the volume of the pressure correction chamber 13 and the deformation of the vibration plate 10 is suppressed. When the outside air pressure becomes higher than the pressure in the vibration chamber 11, the deformable plate 14 forming the wall surface of the pressure correction chamber 13 is deformed and displaced in a direction to reduce the volume of the pressure correction chamber 13, and the deformation of the vibration plate 10 is suppressed. You.
[0036]
In this case, since the gap between the deformable plate 14 and the opposing surface 13a of the pressure correction chamber 13 is narrow, the deformable plate 14 easily contacts the opposing surface 13a of the pressure correction chamber 13; Since the minute projections 16 are provided on the surface on the side of the chamber 13, the minute projections 16 come into contact with the opposing surface 13 a of the pressure compensation chamber 13. This is significantly reduced as compared with the case where the contact surface 13a comes into contact with the facing surface 13a.
[0037]
Thereby, even when the deformable plate 14 comes into contact with the opposing surface 13a of the pressure compensation chamber 13, the contact area is small, so that the van der Waals force, the adsorbed water, and the adsorbing force due to the residual charge acting upon the contact are substantially reduced. Thus, the sticking of the deformable plate 14 can be suppressed. As a result, it is possible to avoid impairing the function of the deformable plate 14, that is, the function of the pressure compensation chamber 13, and to perform a stable compensation operation for a long time. The gap with the opposing surface 13a can be narrowed, so that the size of the head is not increased.
[0038]
Thus, in this head, by providing a means for reducing the contact area on the deformable plate of the pressure correction chamber, a stable correction operation can be performed. Variations in the initial position of the diaphragm due to pressure differences can be suppressed, variations in ink ejection characteristics can be suppressed, stable droplet ejection can be performed, and a highly accurate and highly reliable droplet ejection head can be realized. Therefore, a highly accurate and highly reliable element can be provided also in a micropump or a light modulation device using the electrostatic actuator of the droplet discharge head.
[0039]
Here, the shape of the minute projection 16 is not particularly limited. As the vertical cross-sectional shape, for example, a rectangular shape (square shape) as shown in FIG. 6A, a triangular shape as shown in FIG. 6B, and a trapezoidal shape (deformable plate) as shown in FIG. 14 is wider). In this case, from the viewpoint of the production yield, the stability of the structure, and the function of reducing the contact area, it is particularly preferable that the vertical cross-sectional shape is trapezoidal, that is, the contact surface is further narrowed.
[0040]
The cross-sectional shape is, for example, rectangular (square) as shown in FIG. 7A, circular as shown in FIG. 7B, and triangular as shown in FIG. The shape is not limited to these point shapes, and may be a long shape (linear shape) as shown in FIG.
[0041]
Further, the arrangement of the microprojections 16 is not limited to the arrangement example shown in FIG. 5 described above, but may be a line arrangement such as one row, two rows, three rows, a staggered arrangement, a ring arrangement, or a random arrangement. be able to. However, in the arrangement where the minute projections 16 are provided, the thickness of the deformable plate 14, the short side width, and the distance between the deformable plate 14 and the opposing surface are taken into consideration, and the deformable plate 14 is formed by the pressure difference between the pressure correction chamber 13 and the outside air. It is preferable that the arrangement besides the protrusion 16 does not make contact.
[0042]
In the above-described embodiment, an example is described in which the vibration chambers of a plurality of actuators communicate with each other in the head. However, the present invention can also be applied to a case where the vibration chambers of each actuator are independent. However, when each of the vibration chambers is independent, it is necessary to provide a pressure correction chamber for each independent portion, and to provide a means for reducing the contact area of the deformable portion for each pressure correction chamber.
[0043]
Further, in the case where a configuration in which minute projections are provided also on the rear surface (side surface of the vibration chamber) of the diaphragm to prevent sticking of the diaphragm is adopted, the rear surface of the diaphragm and the surface of the deformable plate on the pressure correction chamber side are At the same time, that is, the minute projections can be provided by the same process using the same material, and in this case, an increase in the process can be prevented.
[0044]
Here, as a method of forming the minute projections, either a method of directly forming the projections on the plane, or a method of forming the engraving on the plane and forming the remaining portions as the minute projections may be used.
[0045]
Next, an ink jet head according to a second embodiment of the droplet discharge head of the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of the pressure correction unit of the head along the longitudinal direction of the deformable plate.
In this head, minute projections 16 are provided on the opposing surface 13a of the pressure correction chamber 13 opposing the deformable plate 14. Even in this case, the same operation and effect as those of the first embodiment can be obtained, and it is possible to cope with a case where it is difficult or difficult to form minute projections on the deformable plate side by a manufacturing process.
[0046]
In addition, in the case of employing a configuration in which minute projections are provided on the surface (electrode side) facing the diaphragm to also prevent sticking of the diaphragm, the diaphragm facing surface and the deformable plate are simultaneously placed on the facing surface. The minute projections can be provided by the same process using the same material, and this can prevent an increase in the number of processes.
[0047]
Next, an ink jet head according to a third embodiment of the droplet discharge head of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of a main portion of the pressure compensating portion of the head and the vibrating chamber along a lateral direction of the deformable plate.
In this head, an insulating film 18 made of a silicon oxide film is formed on the surface of the electrode 12 facing the vibration plate 10, and when the insulating film 18 is formed, the opposing surface 13 a of the pressure compensation chamber 13 facing the deformable plate 14. The micro projections 16 made of a silicon oxide film are formed on the substrate.
[0048]
That is, it is preferable to use a semiconductor technology for forming a microstructure such as an ink jet head. If a pressure compensation chamber can be formed together with the formation of an actuator section, an increase in the number of processes can be suppressed, and cost reduction can be achieved. Can be planned.
[0049]
In this case, if the pressure compensation chamber 13 is formed at the same time as the formation of the vibration chamber 11, there are some restrictions on the configuration of the pressure compensation chamber 13. In the vibration chamber 11, when the electrode 12 abuts on the opposing surface (the surface on the side of the diaphragm 10) at the time of driving, at least one of the electrode surface and the opposing surface is provided so as not to cause an electric short circuit. An insulating layer must be formed. Even when they are not in contact with each other, there is a fear of discharge, so that the presence of an insulating layer increases reliability. When the material of the insulating layer is silicon oxide (silicon oxide film), a forming method can be used in various semiconductor processes.
[0050]
Therefore, in this embodiment, a silicon oxide film is formed as an insulating layer (insulating film) 18 of the actuator section (vibration chamber 11), and is also formed in the pressure correction chamber 13 at the same time. The minute protrusions 16 are formed by removing portions other than the portions corresponding to the minute protrusions 16 by etching.
[0051]
In this case, the minute projections 16 can be formed at the stage of forming a silicon oxide layer for forming the insulating film 18, that is, without any etching. FIG. 11 shows an example of this case.
[0052]
Note that it is not necessary to form the insulating film of the actuator section and the microprojection material layer of the pressure compensation chamber at the same time. Even when the microprojection material layer of the pressure compensation chamber is a silicon oxide film, the insulating layer of the actuator section is formed of silicon oxide. It does not need to be a membrane.
[0053]
In the case where an insulating layer is formed on the diaphragm side, it is preferable to use silicon nitride as the insulating layer. In such a case, it is preferable to form minute projections 16 made of a silicon nitride film also on the deformable plate 14 of the pressure compensation chamber 13.
[0054]
That is, when the silicon oxide film is formed on a low rigidity portion, a compressive stress is generated between the materials, and the low rigidity portion is bent. If the electrostatic actuator does not accurately form the gap length between the electrodes on which the electrostatic force acts, the desired characteristics cannot be obtained. Therefore, the silicon oxide film bends a portion having low rigidity, and as a result, the gap length becomes an undesired value. , Sufficient function as an actuator cannot be expected.
[0055]
On the other hand, since the silicon nitride film is a film having a tensile stress, even if the silicon nitride film is formed at a low rigidity portion, the low rigidity portion does not bend, and the gap length between the electrodes on which electrostatic force acts is changed. As a result, the function of the actuator is not impaired.
[0056]
Therefore, as described above, when silicon nitride is used as an insulating layer necessary for the actuator section, a silicon nitride film is simultaneously formed in the pressure compensation chamber, and the material of the minute projections in the silicon nitride film pressure compensation chamber is formed. It is good to use as.
[0057]
However, also in this case, it is not necessary to simultaneously form the insulating film of the actuator section and the microprojection material layer of the pressure compensation chamber. Even when the microprojection material is a silicon nitride film, the insulating layer of the actuator section is formed of a silicon nitride film. It is not necessary to form with.
[0058]
Next, a specific head configuration and its evaluation will be described.
(Example 1)
A head having fine projections was formed by the following method. This manufacturing method will be described with reference to FIG. FIG. 1A is a cross-sectional view of a 1-bit actuator section, and FIG. 2B is a cross-sectional view of a pressure correction chamber.
[0059]
In FIG. 1A, first, a silicon substrate 31 is coated with SiO 2. ₂ After a film 32 is formed, a polysilicon layer 33 serving as an electrode and a partition is formed, and then engraving is formed by etching so as to form a SiN layer 34, thereby forming the electrode 12 made of the polysilicon layer 33. At this time, the electrodes 12 are electrically independent in each actuator section. Thereafter, SiN 34 is formed by CVD, and SiO ₂ Embed the engraving at 35. Then, after polishing the surface, an SiN layer 36 is formed, and further a polysilicon layer 37 is formed. Thereafter, the internal SiO 2 is formed through a hole 38 provided as shown in FIG. ₂ The vibration chamber 11 is formed by etching and removing 35.
[0060]
In FIG. 2B, formation of the pressure correction chamber is performed in substantially the same process as that of the actuator section. The difference is that the portion of the polysilicon layer 33 corresponding to the bottom surface of the pressure compensation chamber is removed because the electrode 12 is not formed. ₂ After forming the surface 35 and polishing the surface, forming the engraving at the position where the minute projection 16 is to be formed, the SiN layer 36 is formed, and the polysilicon layer 37 is further formed. As a result, the deformable plate 14 in which the minute protrusions 16 are integrally formed by the SiN layer 36 is formed, ₂ By removing 35, the pressure compensation chamber 13 having the minute projections 16 is formed on the back surface of the deformable plate 14.
[0061]
The parameters of each part of the head were as follows.
Diaphragm: thickness t = 2 μm, short side length a = 125 μm, long side length b = 1000 μm
Deformable plate: thickness t = 2 μm, short side length a = 2000 μm, long side length b = 10 mm
Electrode shape: The electrode was formed so as to be parallel to the diaphragm. The air gap length between the electrode and the diaphragm was designed to be 0.2 μm in specifications.
Microprojections: height t = 0.2 μm, area 3 × 3 μm.
The arrangement was in the form of a matrix having a pitch of 60 μm before, after, left and right.
Formed on the back of a deformable plate.
[0062]
(Comparative Example 1)
In the same manufacturing process as in Example 1, a head having no fine protrusions was manufactured. Since no minute projections are produced, SiO ₂ After forming 35 and polishing the surface, the SiN 36 is deposited without forming an engraving at the position where the minute projection 16 is to be formed.
[0063]
(Evaluation method and results)
With respect to the head of Example 1 and the head of Comparative Example 1, the deformable plate is pressed with a needle in the air to bring the deformable plate into contact with the opposing surface, and thereafter, the deformable plate is stuck on the opposing surface. Checked whether.
[0064]
At this time, when evaluation was performed on a plurality of heads, sticking did not occur in the head of Example 1, but sticking occurred almost certainly in the head of Comparative Example 1.
[0065]
Here, the main causes of sticking are considered to be an atomic force, a liquid bridging force, and a hydrogen bonding force. In a deformable portion that causes such sticking, a desired pressure correction cannot be obtained, and reliability as a head cannot be expected.
[0066]
(Example 2)
A head having fine projections was formed by the following method. That is, after an oxide film was formed on a silicon substrate, the oxide film was carved, an electrode was formed by forming TiN on the carved film, and the silicon oxide film was formed as an insulating layer on the electrode. Here, TiN may be formed in the pressure compensation chamber, but is not formed. The silicon oxide film in the pressure compensation chamber is etched to form minute projections, which are used as an electrode substrate.
[0067]
On the other hand, a vibration plate, a common liquid chamber, a deformable plate accompanying the vibration plate, and the like are formed on another silicon substrate by etching, and this is used as a flow path substrate. At this time, the diaphragm and the deformable plate were formed in exactly the same process.
[0068]
Thereafter, the flow channel substrate was directly bonded on the electrode substrate. The number of actuators formed in one head is 192 in one row. Here, all the vibration chambers in one row communicate with one pressure compensation chamber.
[0069]
(Comparative Example 2)
A head having no minute projections was manufactured in the same manufacturing process as in Example 2 described above. Since the fine projections are not formed, the fine projection forming step in the manufacturing process of the electrode substrate is not performed.
[0070]
The parameters of each part of the head were as follows.
Diaphragm: thickness t = 2 μm, short side length a = 125 μm, long side length b = 1000 μm
Deformable plate: thickness t = 2 μm, short side length a = 2000 μm, long side length b = 10 mm
Electrode shape: The electrode was formed so as to be parallel to the diaphragm. The air gap length between the electrode and the diaphragm was designed to be 0.2 μm in specifications.
Microprojections: height t = 0.2 μm, area 3 × 3 μm.
The arrangement was in the form of a matrix having a pitch of 60 μm before, after, left and right.
It was formed on the back surface of the deformable part.
[0071]
(Evaluation method and results)
Regarding the head of Example 2 and the head of Comparative Example 2 described above, the deformable plate is pressed with a needle in air to bring the deformable plate into contact with the opposing surface, and then the deformable plate is stuck on the opposing surface. Checked whether.
[0072]
At this time, when a plurality of heads were evaluated, sticking did not occur in the head of Example 2 but sticking occurred almost certainly in the head of Comparative Example 2.
[0073]
Next, an ink jet head according to a fourth embodiment of the droplet discharge head of the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of the head along a deformable plate longitudinal direction.
In this head, the surface 13b of the pressure compensation chamber 13 facing the deformable plate 14 is subjected to a surface roughening process for increasing the surface roughness. In this case, the surface roughness of the facing surface 13b is the same as the surface roughness in the vibration chamber (when the surface in the vibration chamber is also subjected to the surface roughening process) or is larger than the surface roughness in the vibration chamber (the surface roughness in the vibration chamber). Also when no roughening treatment is performed).
[0074]
In this manner, by performing the surface roughening treatment on the opposing surface 13b of the pressure compensation chamber 13 with which the deformable plate 14 contacts, the contact area at the time of contact can be reduced. Even when the plate 14 contacts the opposing surface 13b of the pressure compensation chamber 13, since the contact area is small, the van der Waals force, adsorption water, and adsorption force due to adsorbed water and residual charges that act upon the contact are substantially suppressed and can be deformed. Sticking of the plate 14 can be suppressed, and as a result, the function of the deformable plate 14, that is, the function of the pressure correction chamber 13 can be prevented from being impaired, and a stable correction operation can be performed for a long time.
[0075]
Next, a specific head configuration and its evaluation will be described.
(Example 3)
The method of fabricating the head is the same as that described in the second embodiment, but instead of forming minute projections, before the direct bonding between the electrode substrate and the vibration substrate, the portion to be the facing surface of the deformable portion is Ar A surface roughening process step of performing roughening by dry etching using a gas is performed.
[0076]
(Comparative Example 3)
The device was manufactured in the same manner as in Example 3, except that no fine protrusions were provided, and the facing surface was not subjected to a roughening treatment.
[0077]
The parameters of each part of the head were as follows.
Diaphragm: thickness t = 2 μm, short side length a = 125 μm, long side length b = 1000 μm
Deformable plate: thickness t = 2 μm, short side length a = 1000 μm, long side length b = 10 mm
Electrode shape: The electrode was formed so as to be parallel to the diaphragm. The air gap length between the electrode and the diaphragm was designed to be 0.2 μm in specifications.
[0078]
(Evaluation method and results)
Regarding the head of Example 3 and the head of Comparative Example 3 described above, the deformable plate is pressed with a needle in the air to bring the deformable plate into contact with the opposing surface, and then the deformable plate is stuck on the opposing surface. Checked whether.
[0079]
At this time, when a plurality of heads were evaluated, sticking did not occur in the head of Example 3, but sticking occurred almost certainly in the head of Comparative Example 3.
[0080]
Next, an ink jet head according to a fifth embodiment of the droplet discharge head of the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of the head along a deformable plate longitudinal direction.
In this head, a hydrophobic film 26 is formed on a surface 13a of the pressure compensation chamber 13 facing the deformable plate 14. Examples of the material of the hydrophobic film 26 include perfluorodecanoic acid (PFDA) and hexamethyl zirazazane (HMDS). HMDS has smaller molecules and is suitable for forming a film in a narrow space. .
[0081]
Thus, by forming the hydrophobic film 26 on the opposing surface 13a of the pressure compensation chamber 13 with which the deformable plate 14 contacts, it is possible to prevent sticking due to liquid bridging force and hydrogen bonding force (sticking due to adsorbed water). Can be. As a result, it is possible to avoid impairing the function of the deformable plate 14, that is, the function of the pressure correction chamber 13, and to perform a stable correction operation for a long period of time.
[0082]
Next, a specific head configuration and its evaluation will be described.
(Example 4)
The method of fabricating the head was the same as that described in Example 2 above, except that no fine protrusions were formed, and after bonding, dipping was performed in HMDS to form a HMDS film in the pressure compensation chamber.
[0083]
(Comparative Example 4)
The device was manufactured in the same manner as in Example 4, except that no fine protrusions were formed and no hydrophobic film was formed.
[0084]
The parameters of each part of the head were as follows.
Diaphragm: thickness t = 2 μm, short side length a = 125 μm, long side length b = 1000 μm
Deformable plate: thickness t = 2 μm, short side length a = 300 μm, long side length b = 10 mm
Electrode shape: The electrode was formed so as to be parallel to the diaphragm. The air gap length between the electrode and the diaphragm was designed to be 0.2 μm in specifications.
[0085]
(Evaluation method and results)
Regarding the head of Example 4 and the head of Comparative Example 4, the deformable plate is pressed with a needle in the air to bring the deformable plate into contact with the opposing surface, and then the deformable plate is stuck on the opposing surface. Checked whether.
[0086]
Next, after leaving the head of Example 4 and the head of Comparative Example 4 for 1 hour in an environment test room at 30 ° C. and 60% relative humidity, the deformable portions of both heads are pushed with a needle, and the deformable portions are placed on the opposing surfaces. The contact was made to check whether the deformable portion was sticked.
[0087]
At this time, when a plurality of heads were evaluated, it was confirmed that the head of Comparative Example 4 did not stick in the air, but did stick in the environmental test room. On the other hand, in the head of Example 4 in which the HMDS film was formed, it was confirmed that sticking did not occur in the air and in the environmental test chamber.
[0088]
Next, an ink jet head according to a sixth embodiment of the droplet discharge head of the present invention will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of the head along a deformable plate longitudinal direction.
In this head, a conductive layer (conductive film) 27 is formed on a surface 13a of the pressure compensation chamber 13 facing the deformable plate 14. Examples of the conductive layer 27 include a metal material such as TiN and a semiconductor material such as polysilicon. Here, the conductive layer 27 is connected to GND (grounded).
[0089]
As described above, by forming the conductive layer 27 on the opposing surface 13a of the pressure compensation chamber 13 with which the deformable plate 14 contacts, static electricity generated in the contact portion for some reason is considered as one of the causes of sticking. Charge can be released, and sticking due to static charge can be prevented. As a result, it is possible to avoid impairing the function of the deformable plate 14, that is, the function of the pressure correction chamber 13, and to perform a stable correction operation for a long period of time.
[0090]
Next, a specific head configuration and its evaluation will be described.
(Example 5)
The method of manufacturing the head is the same as that described in the third embodiment. However, here, a TiN layer was formed in the pressure compensating section simultaneously with the formation of the electrodes in the actuator section. Thereafter, before direct bonding, the oxide film of the TiN layer was removed by dry etching.
[0091]
The parameters of each part of this head were as follows.
Diaphragm: thickness t = 2 μm, short side length a = 125 μm, long side length b = 1000 μm
Deformable plate: thickness t = 2 μm, short side length a = 300 μm, long side length b = 10 mm
Electrode shape: The electrode was formed so as to be parallel to the diaphragm. The air gap length between the electrode and the diaphragm was designed to be 0.2 μm in specification.
[0092]
(Evaluation method and results)
A potential difference is applied between the TiN layer (conductive layer 27) of the pressure compensation chamber and the deformable plate, and the deformable plate is brought into contact with the TiN layer by electrostatic attraction. Thereafter, when the deformable plate and the TiN layer were directly floated, the deformable plate remained sticking to the facing surface. However, when the TiN layer was set to GND, it was confirmed that the deformable plate was detached from the opposing surface and sticking was eliminated.
[0093]
Next, an example of an electrostatic head of another embodiment to which the present invention is applied will be described with reference to FIG.
The head is electrically separated from the vibration plate 10 via an insulating film 10 a on the surface of the vibration plate 10 opposite to the discharge chamber 6, and from a plurality of structures electrically separated from each other. Electrode 42 is provided.
[0094]
In this head, when a pulse potential of 0 V to 40 V is applied to one of the adjacent electrodes 42 and 42 and 0 V is applied to the other, an electrostatic force is generated between the adjacent electrodes 42 and 42 and the free end side attracts. Therefore, the diaphragm 10 bends. As a result, the pressure in the ejection chamber 6 rises sharply, and ink droplets are ejected.
[0095]
In such a head as well, a pressure correction chamber communicating with the vibration chamber 11 is provided as in the above-described embodiments, and at least one surface of the pressure correction chamber is a deformable portion that can be deformed in accordance with the outside air pressure. By providing a means for reducing the contact area between the deformable portion and the surface facing the pressure compensation chamber, a stable droplet ejection operation can be performed for a long period of time.
[0096]
Next, an ink cartridge (ink tank integrated type head) as a liquid supply cartridge according to the present invention will be described with reference to FIG.
The ink cartridge 100 integrates the ink jet head 102 having any one of the above-described embodiments having the nozzle holes 101 and the like, and the ink tank 103 that supplies ink to the ink jet head 102.
[0097]
As described above, by integrating the ink jet head, which is the droplet discharge head according to the present invention, with the ink tank, an ink cartridge (which integrates a highly reliable droplet discharge head having stable droplet discharge characteristics) An ink tank integrated head) can be obtained, and the cost of the tank integrated head can be reduced.
[0098]
Next, an example of an ink jet recording apparatus equipped with the droplet discharge head according to the present invention will be described with reference to FIGS. FIG. 18 is a perspective view of the recording apparatus, and FIG. 19 is a side view of a mechanism of the recording apparatus.
[0099]
The inkjet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 111, a recording head including the inkjet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper cassette (or a paper tray) 114 capable of loading a large number of sheets 113 from the front side is detachably attached to a lower portion of the apparatus main body 111. The manual feed tray 115 for manually feeding the paper 113 can be opened, and the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in. After the image is recorded, the sheet is discharged to a sheet discharge tray 116 mounted on the rear side.
[0100]
The printing mechanism 112 holds the carriage 123 slidably in the main scanning direction (the direction perpendicular to the paper surface of FIG. 19) by a main guide rod 121 and a sub guide rod 122, which are guide members that are horizontally mounted on left and right side plates (not shown). On the carriage 123, a head 124 composed of an inkjet head, which is a droplet discharge head according to the present invention, which discharges ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction intersecting the main scanning direction with a plurality of ink ejection ports, and are mounted with the ink droplet ejection direction facing downward. Each ink cartridge 125 for supplying each color ink to the head 124 is exchangeably mounted on the carriage 123. The head-integrated head (ink cartridge) according to the present invention may be mounted.
[0101]
The ink cartridge 125 has an upper air port that communicates with the atmosphere, a lower supply port for supplying ink to the inkjet head, and a porous body filled with ink inside. Maintains the ink supplied to the inkjet head at a slight negative pressure.
[0102]
Further, although the heads 124 of each color are used as the recording heads here, a single head having nozzles for ejecting ink droplets of each color may be used.
[0103]
Here, the carriage 123 is slidably fitted on the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the front guide rod 122 on the front side (upstream side in the paper conveyance direction). are doing. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a drive pulley 128 and a driven pulley 129 which are driven to rotate by a main scanning motor 127. , And the carriage 123 is reciprocally driven by forward and reverse rotation of the main scanning motor 127.
[0104]
On the other hand, in order to convey the paper 113 set in the paper feed cassette 114 to the lower side of the head 124, the paper 113 is guided by a paper feed roller 131 and a friction pad 132 for separating and feeding the paper 113 from the paper feed cassette 114. A guide member 133, a transport roller 134 that transports the fed paper 113 in a reversed state, a transport roller 135 pressed against the peripheral surface of the transport roller 134, and a leading end that defines an angle at which the paper 113 is fed from the transport roller 134. A roller 136 is provided. The transport roller 134 is driven to rotate by a sub-scanning motor 137 via a gear train.
[0105]
Further, an image receiving member 139 is provided as a paper guide member for guiding the paper 113 sent from the transport roller 134 below the recording head 124 in accordance with the movement range of the carriage 123 in the main scanning direction. On the downstream side of the printing receiving member 139 in the paper transport direction, there are provided a transport roller 141 and a spur 142 which are driven to rotate to transport the paper 113 in the paper discharge direction. Rollers 143 and spurs 144 and guide members 145 and 146 forming a paper discharge path are provided.
[0106]
At the time of recording, the recording head 124 is driven in accordance with an image signal while moving the carriage 123, thereby ejecting ink to the stopped paper 113 to record one line, and after transporting the paper 113 by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 113 has reached the recording area, the recording operation is terminated and the sheet 113 is discharged. In this case, the inkjet head according to the present invention, which forms the head 124, has improved controllability of ink droplet ejection and suppresses characteristic fluctuation, so that an image of high image quality can be stably recorded.
[0107]
In addition, a recovery device 147 for recovering the ejection failure of the head 124 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 123. The recovery device 147 has a cap unit, a suction unit, and a cleaning unit. The carriage 123 is moved to the recovery device 147 side during printing standby, the head 124 is capped by the capping means, and the ejection port is kept in a wet state, thereby preventing ejection failure due to ink drying. In addition, by discharging ink that is not related to printing during printing or the like, the ink viscosity of all the discharge ports is kept constant, and stable discharge performance is maintained.
[0108]
In the event of a discharge failure, for example, the discharge port (nozzle) of the head 124 is sealed by a capping unit, and air bubbles and the like are sucked out of the discharge port by a suction unit through a tube, and ink or dust adhered to the discharge port surface. Is removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.
[0109]
As described above, since the inkjet recording apparatus is equipped with the inkjet head, which is the droplet ejection head according to the present invention, stable droplet ejection characteristics can be obtained over a long period, and recording with high image quality can be performed. it can.
[0110]
In the above embodiment, an example in which the droplet discharge head is applied to an inkjet head has been described. However, as a droplet discharge head other than the inkjet head, for example, a droplet discharge head that discharges a liquid resist as a droplet, a DNA The present invention can be applied to other droplet discharge heads such as a droplet discharge head that discharges the sample as droplets. Also applicable to micro pumps, optical devices (optical modulation devices), micro switches (micro relays), multi-optical lens actuators (optical switches), micro flow meters, pressure sensors, etc. can do.
[0111]
【The invention's effect】
As described above, according to the electrostatic actuator of the present invention, at least one surface of the pressure correction chamber communicating with the vibration chamber is provided with a deformable portion that can be displaced in accordance with the external pressure. Since the configuration is provided with means for reducing the contact area when the possible portion comes into contact with the facing surface, a small actuator having stable operation characteristics can be obtained.
[0112]
According to the electrostatic actuator according to the present invention, at least one surface of the pressure correction chamber communicating with the vibration chamber is provided with a deformable portion that can be displaced in accordance with an external pressure, and the deformable portion of the pressure correction chamber is provided. Since the configuration is such that the hydrophobic film is formed on the contacting surface, a small actuator having stable operation characteristics can be obtained.
[0113]
According to the electrostatic actuator according to the present invention, at least one surface of the pressure correction chamber communicating with the vibration chamber is provided with a deformable portion that can be displaced in accordance with the outside air pressure, and the deformable portion of the pressure correction chamber is provided. Since the conductive layer is formed on the contacting surface, a small actuator having stable operation characteristics can be obtained.
[0114]
According to the droplet discharge head according to the present invention, since the droplet discharge head includes the electrostatic actuator according to the present invention, stable droplet discharge characteristics are obtained, and reliability and image quality are improved.
[0115]
According to the inkjet recording apparatus of the present invention, since the inkjet head that ejects ink droplets is the droplet ejection head of the present invention, high-quality recording can be performed.
[0116]
According to the liquid supply cartridge according to the present invention, since the droplet discharge head according to the present invention and the station supply tank are integrated, a cartridge having a head that achieves stable droplet discharge characteristics and improves reliability and image quality Is obtained.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an inkjet head according to a first embodiment of a droplet discharge head according to the present invention including an electrostatic actuator according to the present invention.
FIG. 2 is an explanatory cross-sectional view of an actuator section of the head along a longitudinal direction of a diaphragm.
FIG. 3 is an explanatory cross-sectional view of the actuator section of the head taken along the lateral direction of the diaphragm.
FIG. 4 is an explanatory cross-sectional view of a pressure compensating portion of the head along a deformable plate longitudinal direction.
FIG. 5 is an explanatory cross-sectional view of the pressure compensating section of the head along the width direction of the deformable plate.
FIG. 6 is an explanatory view illustrating an example in which the vertical projections of the minute projections are different.
FIG. 7 is an explanatory view illustrating an example in which the cross-sectional shape of the minute projection is different.
FIG. 8 is an explanatory plan view for explaining another example of the cross-sectional shape and arrangement example of the minute projections.
FIG. 9 is an explanatory cross-sectional view of the pressure correction unit of the inkjet head according to the second embodiment along the longitudinal direction of the deformable plate;
FIG. 10 is an explanatory cross-sectional view of the inkjet head according to the third embodiment, taken along the lateral direction of the diaphragm.
FIG. 11 is an explanatory cross-sectional view of the pressure correction unit of the inkjet head along the longitudinal direction of the deformable plate for explaining another example of the embodiment;
FIG. 12 is an explanatory sectional view for explaining a manufacturing process of the droplet discharge head according to the present invention;
FIG. 13 is an explanatory cross-sectional view of the pressure correction unit of the inkjet head according to the fourth embodiment along the longitudinal direction of the deformable plate;
FIG. 14 is an explanatory cross-sectional view of the pressure correction unit of the inkjet head according to the fifth embodiment along the longitudinal direction of the deformable plate;
FIG. 15 is an explanatory cross-sectional view of the pressure correction unit of the inkjet head according to the sixth embodiment along the longitudinal direction of the deformable plate;
FIG. 16 is an explanatory cross-sectional view taken along the transverse direction of a diaphragm, illustrating an example of another type of electrostatic liquid droplet ejection head to which the present invention is applied.
FIG. 17 is a perspective explanatory view for explaining a liquid supply cartridge according to the present invention.
FIG. 18 is a perspective explanatory view illustrating an example of an ink jet recording apparatus according to the present invention.
FIG. 19 is an explanatory diagram of a mechanism of the recording apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Flow path board, 2 ... Electrode board, 3 ... Nozzle board, 4 ... Nozzle hole, 6 ... Discharge chamber, 7 ... Fluid resistance part, 8 ... Common liquid chamber, 10 ... Vibration plate, 11 ... Vibration chamber, 12 ... Electrodes, 13: pressure compensation chamber, 14: deformable plate, 15: communication path, 16: minute projection, 26: hydrophobic film, 27: conductive layer, 100: ink cartridge, 124: recording head.

Claims (10)

A vibration chamber having a deformable diaphragm as at least one surface, an electrode facing the diaphragm, and a pressure correction chamber communicating with the vibration chamber, wherein at least one surface of the pressure correction chamber has A deformable portion that can be displaced in accordance with an external pressure is provided, and in an electrostatic actuator that deforms the vibration plate with electrostatic force, means for reducing a contact area when the deformable portion comes into contact with an opposing surface. An electrostatic actuator comprising: 2. The electrostatic actuator according to claim 1, wherein minute projections are formed on the pressure correcting chamber side of the deformable portion. 3. The electrostatic actuator according to claim 1, wherein minute projections are formed on a surface facing the deformable portion. 4. The electrostatic actuator according to claim 2, wherein a material of the minute projection is silicon oxide or silicon nitride. 5. 2. The electrostatic actuator according to claim 1, wherein a surface of the pressure correction chamber with which the deformable plate comes into contact is subjected to a surface roughening process for increasing a surface roughness. 3. . A vibration chamber having a deformable diaphragm as at least one surface, an electrode facing the diaphragm, and a pressure correction chamber communicating with the vibration chamber, wherein at least one surface of the pressure correction chamber has A deformable portion that can be displaced in accordance with an outside air pressure is provided, and in an electrostatic actuator that deforms the diaphragm with electrostatic force, a hydrophobic film is formed on a surface of the pressure correction chamber where the deformable portion contacts. An electrostatic actuator. A vibration chamber having a deformable diaphragm as at least one surface, an electrode facing the diaphragm, and a pressure correction chamber communicating with the vibration chamber, wherein at least one surface of the pressure correction chamber has A deformable portion capable of being displaced in accordance with an external pressure is provided, and in an electrostatic actuator that deforms the diaphragm with electrostatic force, a conductive layer is formed on a surface of the pressure correction chamber where the deformable portion contacts. An electrostatic actuator. 2. A droplet discharge head comprising a nozzle for discharging droplets, a discharge chamber communicating with the nozzle, and an electrostatic actuator for pressurizing the liquid in the discharge chamber, wherein the electrostatic actuator is provided. 8. A droplet discharge head, which is the electrostatic actuator according to any one of items 7 to 7. An inkjet recording apparatus equipped with an inkjet head for ejecting ink droplets, wherein the inkjet head is the droplet ejection head according to claim 8. 9. A droplet discharge head according to claim 8, wherein the droplet discharge head is a liquid supply cartridge in which a droplet discharge head that discharges droplets and a liquid supply tank that supplies liquid to the droplet discharge head are integrated. A liquid supply cartridge characterized by the above-mentioned.

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