JP2012076258A - Liquid droplet ejection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet ejection device, capable of efficiently collecting and discharging air bubbles and excelling in ejection stability.SOLUTION: The liquid droplet ejection device includes: a first container in which liquid is stored; a second container that has a first aperture, into which the liquid flowing out from the first container flows, and a second aperture from which the liquid flows out; and a head into which the liquid flowing out from the second aperture flows, and which ejects the liquid. The second aperture is located at the highest position in a vertical direction out of an inner wall surface of the second container. The liquid droplet ejection device has a carriage which reciprocates in a predetermined direction in a state where the second container and the head are mounted.

Description

  The present invention relates to a droplet discharge device.

  2. Description of the Related Art Conventionally, an ink supply system that supplies ink to an ejection head that can eject ink from an ink tank that contains ink via an ink supply pipe is known.

  For example, Patent Document 1 includes a sub tank in which an ink cartridge containing an ink containing a pigment and a print head are connected by an ink flow path, and a fixed amount of ink is always held in the ink flow path. Ink supply systems are described. Patent Document 1 describes that the ink can be agitated by a stirrer or the like provided in the sub-tank to reduce sedimentation of components such as pigments contained in the ink.

JP 2006-272648 A

  However, in the above-described conventional technology, there are cases where bubbles are generated in the ink flow path or the sub tank, resulting in ink ejection failure.

  One of the objects according to some aspects of the present invention is to provide a droplet discharge device that can efficiently collect and discharge bubbles and has excellent discharge stability.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the liquid supply system according to the present invention is:
A first container containing liquid and allowing the liquid to flow out;
A first opening through which the liquid flowing out from the first container flows in, and a second container having a second opening through which the liquid flows out;
A head from which the liquid flowing out from the second opening flows in and discharges the liquid;
Have
The second opening is at the highest position in the vertical direction on the inner wall surface of the container.

  According to the aspect described in Application Example 1, when bubbles are generated in the second container, the second opening is located at the highest position in the vertical direction on the inner wall surface of the second container. Bubbles are efficiently collected in the second opening, and bubbles in the second container are efficiently discharged from the second opening. Therefore, the droplet discharge device of this aspect is excellent in the discharge stability of the head.

[Application Example 2]
In application example 1,
Furthermore, it can have a carriage mounted with the second container and the head and reciprocating in a predetermined direction.

  According to the aspect described in Application Example 2, when bubbles are generated in the second container, the bubbles in the second container are easily moved to the second opening by the movement of the carriage. Thereby, the bubbles in the second container are more efficiently discharged from the second opening.

[Application Example 3]
In application example 1 or application example 2,
The inner wall surface of the second container may have a vertically upward convex portion, and the second opening may be located at the convex portion.

  According to the aspect described in the application example 3, the bubbles easily gather at the convex portion including the highest position in the vertical direction of the inner wall surface of the second container. Therefore, the bubbles gathered at the convex portion are positioned at the convex portion. Is efficiently discharged from the second opening.

[Application Example 4]
In any one of Application Examples 1 to 3,
The inner wall surface of the second container may be concentrated toward the second opening.

  According to the aspect described in the application example 4, since the bubbles are more easily moved along the inner wall surface, the bubbles are more efficiently discharged from the second opening.

[Application Example 5]
In any one of Application Examples 1 to 4,
Furthermore, a bubble discharge mechanism that discharges bubbles in the second container through the head can be provided.

  According to the aspect described in Application Example 5, the bubbles in the second container are discharged more efficiently.

[Application Example 6]
In application example 5,
And a pipe connecting the second opening and the head;
A detection unit for detecting bubbles inside the tube;
A control unit for controlling the bubble discharge mechanism and the detection unit;
With
The control unit starts the cleaning process at a given timing,
The control unit operates the detection unit in the cleaning process, determines the presence or absence of bubbles based on the output of the detection unit,
In the case where it is determined that there is a bubble, the control unit,
Operate the bubble discharge mechanism, and count the number of operations of the bubble discharge mechanism after starting the cleaning process,
If the count value is less than the predetermined value, the cleaning process can be performed again from the operation of the detection unit.

  According to the aspect described in Application Example 6, bubbles generated inside the tube can be efficiently discharged by the cleaning process.

[Application Example 7]
In Application Example 6,
In the cleaning process, the control unit can end the cleaning process if the count value is equal to or greater than a predetermined value.

  According to the aspect described in the application example 7, when the operation of the bubble discharge mechanism exceeds a preset count value, it is determined that a defect such as an abnormality of the bubble has occurred, and the control unit performs cleaning. Processing can be terminated.

[Application Example 8]
In Application Example 7,
Furthermore, it has a transmitter that transmits an error signal,
The control unit can terminate the cleaning process and cause the transmission unit to transmit an error signal.

  According to the aspect described in the application example 8, since an error signal is transmitted from the transmission unit, for example, a user or the like can easily know the occurrence of an error.

The perspective view which shows typically the droplet discharge apparatus which concerns on this embodiment. The schematic diagram of the side surface of the 2nd container in the droplet discharge apparatus which concerns on this embodiment. The schematic diagram of the side surface of the 2nd container in the droplet discharge apparatus which concerns on this embodiment. The perspective view which shows typically the 2nd container in the droplet discharge apparatus which concerns on this embodiment. 6 is a flowchart showing a flow of a first recording operation in the present embodiment. 9 is a flowchart showing the flow of a second recording operation in the present embodiment. 1 is a perspective view schematically showing an ink jet printer according to an embodiment.

  Hereinafter, although embodiment of this invention is described, this invention is not restrict | limited to these.

1. Droplet Discharge Device The droplet discharge device according to the present embodiment includes a first container, a second container, and a head. FIG. 1 is a perspective view schematically showing a droplet discharge device 100 according to the present embodiment. Hereinafter, the droplet discharge apparatus 100 according to the present embodiment will be described with reference to FIG.

1.1. First Container The droplet discharge device 100 according to the present embodiment includes a first container 10 that stores a liquid and causes the liquid to flow out. As shown in FIG. 1, the first container 10 is connected to the second container 20 via the first pipe 30. Thereby, the liquid in the first container 10 can be supplied to the second container 20. In the example of FIG. 1, the first container 10 is connected to the second container 20 via the first pipe 30, but is not limited to this, and the first container 10 and the second container 20 are connected to each other. It may be directly connected without going through one pipe 30.

  The first container 10 preferably has a structure capable of replenishing the consumed liquid again, and more preferably has a structure capable of replenishing the liquid during the operation of the droplet discharge device 100. When the first container 10 has a structure in which the liquid can be replenished during the operation of the droplet discharge device 100, the liquid can be replenished to the first container 10 without stopping the operation of the droplet discharge device 100. Can be further improved.

  The liquid accommodated in the first container 10 in this specification is not limited to a solution, but also includes a dispersion such as a suspension or an emulsion. For example, the liquid contained in the first container 10 may be an ink composition, an organic EL display material, a color filter material such as a liquid crystal display, an FED (field emission display) material, an electrode such as an electrophoretic display, Examples thereof include color filter materials and bioorganic materials used for biochip production.

  Moreover, the liquid accommodated in the 1st container 10 can contain the component which can settle. The component that can be precipitated is, for example, a component having a high specific gravity with respect to a solvent, and in the ink composition, for example, is at least one selected from inorganic pigments, metal pigments, and hollow resin particles. May contain components bound or adsorbed to the.

  Examples of the inorganic pigment include titanium dioxide, silicon oxide, aluminum oxide, zinc oxide, iron oxide, and carbon black.

  Examples of the metal pigment include aluminum, gold, silver, copper, brass, titanium, and the like, or alloys thereof.

  Examples of the hollow resin particles include hollow resin particles described in specifications such as US Pat. No. 4,880,465 and Japanese Patent No. 3,562,754. The hollow resin particles are, for example, those having a cavity inside and an outer shell formed of a resin having liquid permeability. The hollow resin particles can be used as a white pigment.

  Hereinafter, a typical white ink composition will be described as an example of the liquid stored in the first container 10. For example, in the white ink composition, the above-described titanium dioxide can be used as a white pigment. In this case, the content of titanium dioxide is preferably 5% by mass or more and 20% by mass or less, and more preferably 8% by mass or more and 15% by mass or less with respect to the total mass of the white ink composition. If the content of titanium dioxide exceeds the above range, clogging of the head 40 may occur. Further, if the content of titanium dioxide is less than the above range, the whiteness of the recorded image may be insufficient.

  The white ink composition can include a resin for fixing the pigment. Examples of such resins include acrylic resins (for example, Almatex (manufactured by Mitsui Chemicals)), urethane resins (for example, WBR-022U (manufactured by Taisei Fine Chemical Co., Ltd.)), and the like. The content of the resin is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 3% by mass or less with respect to the total mass of the white ink composition.

  The white ink composition can contain at least one selected from alkanediols and glycol ethers. When alkanediol or glycol ether is contained, the wettability of the surface to be ejected such as the medium to be ejected can be improved and the permeability of the ink can be enhanced.

  Examples of the alkanediol include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, etc. , 2-alkanediol. Among these, 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol having 6 to 8 carbon atoms are preferable because of their particularly high permeability to the medium to be discharged.

  As glycol ethers, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol Mention may be made of lower alkyl ethers of polyhydric alcohols such as monomethyl ether, triethylene glycol monobutyl ether and tripropylene glycol monomethyl ether.

  When these alkanediol and glycol ether are contained, the content of at least one selected from these alkanediol and glycol ether is preferably 1% by mass with respect to the total mass of the white ink composition. It is 20 mass% or less, More preferably, it is 1 mass% or more and 10 mass% or less.

  The white ink composition can also contain an acetylene glycol surfactant or a polysiloxane surfactant. Is preferred. When an acetylene glycol surfactant or a polysiloxane surfactant is contained, the wettability of the white ink composition to the surface to be ejected such as the medium to be ejected is increased, and the permeability of the ink can be enhanced. .

  Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, Examples include 5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol, and the like. Commercially available products can also be used as the acetylene glycol surfactants. For example, Olphine E1010, STG, Y (above, manufactured by Nissin Chemical Co., Ltd.), Surfynol 104, 82, 465, 485, TG ( As described above, Air Products and Chemicals Inc.) can be used.

  Commercially available products can be used as the polysiloxane surfactant, and for example, BYK-347 and BYK-348 (manufactured by Big Chemie Japan) can be used.

  Further, the white ink composition may contain other surfactants such as an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant.

  The content of the surfactant is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 0.5% by mass or less, with respect to the total mass of the white ink composition. It is.

  The white ink composition may contain a polyhydric alcohol. When polyhydric alcohol is contained, for example, when the white ink composition is applied to an ink jet recording apparatus, drying of the ink is suppressed, and clogging of the white ink composition in the ink jet recording head portion can be reduced. it can.

  Examples of such polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, Examples include trimethylolethane and trimethylolpropane.

  The content of the polyhydric alcohol is preferably 0.1% by mass or more and 30% by mass or less, and more preferably 0.5% by mass or more and 20% by mass or less, with respect to the total mass of the white ink composition. .

  The white ink composition can contain water as a solvent. As water, it is preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water. In particular, it is more preferable to sterilize these waters by irradiation with ultraviolet rays or addition of hydrogen peroxide, because generation of mold and bacteria can be suppressed over a long period of time.

  Further, the white ink composition may be prepared by using a fixing agent such as water-soluble rosin, an antifungal agent / preservative such as sodium benzoate, an antioxidant / ultraviolet absorber such as allophanate, a chelating agent, triethanol, as necessary. You may contain additives, such as pH adjusters, such as an amine, and an oxygen absorber. These additives can be used alone or in combination of two or more.

  Although the water-based ink composition has been described as an example of the white ink composition, an ultraviolet curable ink or the like may be used. In the case of using an ultraviolet curable ink, examples of components that can settle include a photopolymerization initiator.

1.2. Second Container The droplet discharge device 100 according to the present embodiment includes a second container 20. As shown in FIG. 1, the second container 20 is connected to the first container 10 via the first pipe 30 and is connected to the head 40 via the second pipe 32. The first tube 30 is connected to the first opening 20 </ b> A in the second container 20, and the second tube 30 is connected to the second opening 20 </ b> B in the second container 20.

  The liquid flowing out from the first container 10 flows through the first pipe 30 and flows into the second container 20 from the first opening 20 </ b> A of the second container 20. At this time, the liquid that has flowed into the second container 20 is temporarily stored in the second container 20, thereby suppressing the occurrence of concentration changes in the components contained in the liquid. Then, the liquid that has flowed into the second container 20 and temporarily stored flows out of the second opening 20B of the second container 20, flows through the second pipe 32, and then flows into the head 40. . The head 40 can discharge the supplied liquid through such a path.

  The second opening 20 </ b> B of the second container 20 is at the highest position in the vertical direction on the inner wall surface of the second container 20. For example, as illustrated in FIG. 1, the inner wall surface of the second container 20 includes an upper surface 22 having a convex portion in the vertically upward VD, a bottom surface 24, and side surfaces 26 a to 26 d. Specifically, the upper surface 22 has a quadrangular pyramid shape. A second opening 20B is provided at the apex of the upper surface of the quadrangular pyramid shape. Note that HD in FIG. 1 indicates the horizontal direction.

  Here, the inside of the droplet discharge device 100 is supplied by, for example, a gas (for example, air) mixed at the time of manufacturing the droplet discharge device 100 or a gas mixed at the time of filling the liquid into the first container 10. Bubbles may be generated in the liquid. The bubbles generated in this way may move into the second container 20 along with the liquid flow described above. Since the bubbles moved into the second container 20 have a specific gravity smaller than that of the liquid supplied into the second container 20, they tend to rise in the liquid and gather at the highest position in the second container 20 in the vertical direction. Become.

  In addition, bubbles may be generated in the second container 20. Bubbles generated in the second container 20 are likely to gather at the highest position in the vertical direction in the second container 20, similarly to the bubbles generated in the first container 10 and the first tube 32.

  Therefore, as shown in FIG. 1, when the second opening 20B of the second container 20 is located at the highest position in the vertical direction on the inner wall surface of the second container 20, the bubbles in the second container 20 are efficiently discharged. 2 is discharged from the opening 20B.

  The direction in which the second opening 20B in the second container 20 is opened is not particularly limited as long as the second opening 20B is at the highest position in the vertical direction on the inner wall surface of the second container 20. Absent. 2 and 3 are side views schematically showing the second container 20, and specifically show the second container 20 as viewed from the second side face 26d side. In the example of FIG. 2, the second opening 20 </ b> B is provided in the second container 20 so as to open in the vertical direction upward VD. On the other hand, in the example of FIG. 3, the second opening 20 </ b> B is provided in the second container 20 so as to open in the horizontal direction HD.

  In the example of FIG. 1, the inner wall surface of the second container 20 has a quadrangular pyramid shape provided with the second opening 20 </ b> B, but is not limited thereto, and has a convex portion in the vertical upward VD. Also good. Bubbles in the second container 20 are likely to gather at the convex portion when the convex portion includes the highest position in the vertical direction on the inner wall surface of the second container 20. In this way, the bubbles in the second container 20 are more efficiently discharged from the second opening 20B.

  Further, the shape of the convex portion is not particularly limited, but may be, for example, a cone shape such as a polygonal pyramid or a cone, or a curved surface shape such as a cylinder. In addition, as another example in which the convex portion has a curved surface shape, one including at least a part of a sphere or an ellipsoid (for example, a semi-ellipsoid, a hemisphere, or the like) can be given. In addition, as for the shape of a convex part, what has the convex part which the inner wall face of the 2nd container 20 concentrated toward the 2nd opening 20B like a hemisphere or a cone is the most preferable.

  The fact that the inner wall surface of the second container 20 is concentrated toward the second opening 20B means that the cutting position appears in the vertical direction on the cut surface that appears when the second container 20 is cut in the horizontal direction. It shows that the area which becomes the inner side of an inner wall surface decreases, so that.

  FIG. 4 is a perspective view schematically showing the second container 120 in the droplet discharge device according to the present embodiment. The second container 120 in FIG. 4 has a curved surface 123 convex upward in the vertical direction VD and a bottom surface 120 on the inner wall surface thereof. In the example shown in the drawing, the curved surface convex upward in the vertical direction VD has a semi-ellipsoidal shape (so-called dome shape). The second opening 120B provided on the inner wall surface of the second container 120 in FIG. 4 is provided at the highest position in the vertical direction of the inner wall surface of the second container 120, similarly to the second opening 20B in FIG. . Therefore, the bubbles in the second container 120 in FIG. 4 are efficiently discharged from the second opening 120B in the same manner as the bubbles in FIG.

  In addition, when the convex portion has a cone shape or a curved surface shape, the bubbles in the second container 20 are likely to move along the cone shape portion or the curved surface shape portion, and are easily discharged from the second opening 20B. Become. The shape of the convex portion is more preferably a cone or a curved surface among the shapes exemplified above. Here, the polygonal pyramid has a plurality of sides for each connection portion between the surfaces forming the polygonal pyramid. In some cases, the bubbles in the second container 20 are likely to stay on the sides of the polygonal cone. On the other hand, when the shape of the convex portion is a cone or a curved surface, the number of sides is smaller than that of the polygonal pyramid. Therefore, the bubbles in the second container 20 are more easily discharged from the second opening 20B more efficiently when the convex portion is a cone or a curved surface than when the shape of the convex portion is a polygonal pyramid.

  The droplet discharge device 100 can include a stirring unit that stirs the liquid in the second container 20. The stirring means is not particularly limited. For example, a second mechanism 20 may be used to move the second container 20 fixed to the moving device by moving the moving device back and forth and to the left and right, and to agitate the liquid inside. A mechanism that vibrates and stirs the liquid in the container 20, a mechanism that moves and stirs the liquid in the second container 20 by tilting the second container 20, and a magnet that moves from the outside of the second container 20 Examples thereof include a mechanism having a mechanism for moving the magnetic body disposed in the second container 20 and stirring the liquid in the second container 20. If the stirring means has at least one of the mechanisms as described above, the liquid in the second container 20 is stirred regardless of whether the droplet discharge device has a line type head or a serial type head. can do.

  Further, when the droplet discharge device 100 has the stirring means, the bubbles in the second container 20 easily move to the second opening 20B in the second container 20 together with the stirring of the liquid in the second container 20. Become. In this way, the bubbles in the second container 20 are more efficiently discharged from the second opening 20B.

  Note that the line-type head in this specification means that the head 40 is formed wider than the width of the medium to be ejected, and the head 40 ejects droplets onto the medium to be ejected without moving. When the head provided in the droplet discharge device 100 is a line-type head, the installation position of the second container 20 is not particularly limited, and for example, the second container 20 is installed at a position adjacent to the head. can do.

  In addition, the serial type head in this specification is such that the head 40 is mounted on a carriage that moves in a predetermined direction, and the head moves along with the movement of the carriage, thereby ejecting droplets onto the target medium. It refers to things. Even when the head provided in the droplet discharge device is a serial head, the installation position of the second container 20 is not particularly limited, and can be mounted on a carriage, for example.

  In the case where the droplet discharge device 100 includes a serial head, as a stirring means other than the above, the second container 20 is mounted on a carriage (described later), and the second container 20 is moved along with the movement of the carriage. The liquid in the second container 20 can be stirred. In this way, it is not necessary to provide a separate mechanism for stirring the liquid in the second container 20, and the liquid in the second container 20 can be stirred using the carriage moving mechanism. For this reason, when the second container 20 is mounted on the carriage, the liquid droplet ejection device 100 with further excellent liquid stirring efficiency is obtained. In this case, the bubbles in the second container 20 easily move to the second opening 20B in the second container 20 along with the movement of the carriage. Thereby, the bubbles in the second container 20 are more easily discharged from the second opening 20B.

  In addition, when using the above-described stirring means in which the second container 20 is mounted on the carriage, it is preferable to place a stirring bar in the second container 20 in advance. Thereby, since the stirring bar moves with the movement of the second container 20, the stirring efficiency of the liquid in the second container 20 can be improved. Moreover, since the bubbles in the second container 20 are more easily moved to the second opening 20B by the movement of the stirring bar, the bubbles are more easily discharged from the second opening 20B.

  The shape of the stirrer may be any shape that can move in the second container 20, and examples thereof include a spherical shape, a rugby ball type, and a cylindrical type.

1.3. Head The droplet discharge device 100 according to the present embodiment includes a head 40 that flows in the liquid that flows out from the second opening 20B in the second container 20 and discharges the liquid. Further, the head 40 has a function of discharging bubbles in the second container 20 as the liquid is discharged. The operation of discharging the bubbles in the second container 20 together with the discharge of the liquid from the head 40 may be a so-called flushing operation of discharging the liquid other than the medium to be discharged.

  In the example of FIG. 1, the head 40 is connected to the second container 20 via the second pipe 32, but the present invention is not limited to this, and the second container 20 and the head 40 do not pass through the second pipe 32. It may be connected directly to.

  The head 40 of the droplet discharge device 100 according to the present embodiment may be the line type described above or a serial type. The head 40 may have a plurality of nozzle holes, and can discharge liquid from the nozzle holes.

1.4. Other Configurations The droplet discharge device 100 according to the present embodiment can include the following configurations.

  The droplet discharge device according to the present embodiment may include a first tube 30 and a second tube 32. As described above, the first pipe 32 connects the first container 10 and the second container 20 and supplies the liquid in the first container 10 into the second container 20. The first pipe 32 may be connected to any part of the first container 10, and may be connected to any part of the second container 20. The inner diameter of the first tube 30 is not particularly limited, but when there is a stirrer in the second container 20, the inner diameter of the first tube 30 is such that the stirrer does not move into the first tube 30. You can do it. For example, the inner diameter of the first tube 30 is preferably 2 mm or more and 5 mm or less, and more preferably 2 mm or more and 4 mm or less.

  The second pipe 32 is preferably connected to the second opening 20B in the second container 20. Thereby, the air bubbles collected in the second opening 20 are efficiently discharged from the head via the second tube 32. Since the inner diameter of the second pipe 32 is the same as that of the first pipe 30, the description thereof is omitted.

  The second pipe 32 can have a valve 55. The valve 55 can be stored in a closed state when the liquid supply system 100 is stopped, thereby storing a predetermined amount of bubbles. The position where the valve 55 is provided is not particularly limited as long as it is provided in the second pipe 32.

  Further, the droplet discharge device 100 according to the present embodiment can include a bubble detection sensor 56 as a detection unit. The bubble detection sensor 56 has a function of detecting bubbles. The bubble detection sensor 56 is provided in the second pipe 32 in the example of FIG. 1, but is not limited thereto, and may be provided in the vicinity of the second opening 20 </ b> B in the second container 20. When the bubble detection sensor 56 is installed in the vicinity of the second opening 20B in the second container 20, bubbles near the second opening 20B are supplied to the head 40 during image recording, and ejection failure of the head 40 occurs. Can be prevented in advance.

  As the bubble detection sensor 56, for example, a sensor using a piezoelectric element can be used. When the bubble detection sensor 56 uses a piezoelectric element, the configuration and material used of the piezoelectric element are not particularly limited. For example, a lower electrode made of platinum or the like is provided on a diaphragm made of zirconium oxide or the like, and the lower electrode It is possible to use one having a piezoelectric layer made of lead zirconate titanate or the like and an upper electrode made of platinum or the like thereon.

  For example, when such a piezoelectric element is used as a part of the bubble detection sensor 56, the presence or absence of bubbles is detected by attaching the piezoelectric element so that the diaphragm becomes a part of the inner wall of the third tube 54. be able to. The presence or absence of bubbles can be determined by detecting the characteristics (frequency, etc.) of residual vibration of the diaphragm after vibrating the diaphragm by applying electric energy to the piezoelectric element. Specifically, the remaining vibration characteristic of the diaphragm is such that the portion where the bubble detection sensor 56 is provided in the second tube 32 is filled with the liquid and the bubble is included in a part of the liquid. It will change. The bubble detection sensor 56 can determine the presence or absence of bubbles by detecting such a change in vibration characteristics.

  As shown in FIG. 1, when the second pipe 32 includes the valve 55 and the bubble detection sensor 56, the distance from the bubble detection sensor 56 to the second opening 20B is shorter than the distance from the valve 55 to the second opening 20B. It is preferable. That is, the bubble detection sensor 56 is closer to the second opening 20B than the valve 55. Thereby, if the valve 55 is in the closed state, the bubbles can be stored in the second pipe 32, so that the accuracy of the bubble detection of the bubble detection sensor 56 is improved.

  The droplet discharge device 100 according to the present embodiment can include a carriage that moves in a predetermined direction. For example, the carriage can reciprocate in a predetermined direction by the power of a carriage motor serving as a drive source. The carriage can mount the second container 20 and the head 40 described above. When the second container 20 is mounted on the carriage, the liquid in the second container 20 is agitated as the carriage moves. Thereby, since the sufficiently stirred liquid is supplied to the head 40, it is possible to discharge a good liquid with little concentration change of the contained components. Further, since the head 40 can move together with the carriage, the liquid can be ejected to a desired position on the medium to be ejected. Further, when the second container 20 is mounted on the carriage, the bubbles in the second container 20 are easily moved to the second opening 20B in the second container 20 by the movement of the carriage. Thereby, the bubbles in the second container 20 are easily discharged from the second opening 20B.

  The droplet discharge device 100 according to this embodiment may include a bubble discharge mechanism. The bubble discharge mechanism may be provided in any part of the droplet discharge device 100 as long as it is connected to the head 40 when the bubbles in the second container 20 are discharged. The bubble discharge mechanism is configured by a vacuum pump, a tube pump, or the like, and has a function of forcibly sucking bubbles in the second container 20 through the head 40. As a tube pump, what is described in FIG. 13 of Unexamined-Japanese-Patent No. 2003-165231 can be used, for example. Specifically, the tube pump disclosed in the document discharges the liquid containing bubbles from the second container 20 by discharging the air in the hose (tube) with a pump roller. The bubble discharge mechanism can employ various discharge mechanisms that discharge ink, such as the above-described flushing operation.

1.5. Recording Operation As described above, the bubbles in the second container 20 are discharged from the head 40. Hereinafter, one aspect of the recording operation including the bubble discharging operation in the case of using the droplet discharge device 100 according to the present embodiment will be described according to the flow shown in FIGS.

1.5.1. First Recording Operation FIG. 5 is a flowchart showing a first recording operation including a bubble discharging operation when an inkjet printer 300 described later is used as the droplet discharge device 100. The droplet discharge device 100 according to the present embodiment can perform the first recording operation including the bubble discharge operation according to the flow of FIG. 5 when the bubble detection sensor 56 is not provided.

  As shown in the flowchart of FIG. 5, first, when a control unit 60 (described later) in the ink jet printer 300 receives an image recording command (step 1, hereinafter, also referred to as “image recording command”), the second container 20. Bubbles collected in the second opening 20B are discharged from the head 40 (step 2, hereinafter also referred to as “bubble discharge operation”). Note that the above-described bubble discharging operation is performed using the ejection of the head, but is not limited to this, and may be performed, for example, by sucking bubbles using the above-described bubble discharging mechanism.

  The bubble discharging operation is preferably performed accompanying the image recording command, but is not necessarily limited to this mode, and may be performed accompanying another operation. The bubble discharging operation is performed when an image recording command is received. However, the present invention is not necessarily limited to this mode, and when the image recording command is not received (for example, when the power of the droplet discharge device 100 is turned on, , When the power is turned off).

  The bubble discharge operation is provided in a means for forcibly discharging bubbles (for example, input means in a host device such as a PC connected to the droplet discharge device 100 by wire or wireless, etc., in the droplet discharge device 100. May be executed by a forced cleaning button). In this case, the control unit 60 can receive a command from the means for forcibly discharging the bubble and execute the bubble discharge operation.

  Next, when the second container 20 is installed on the carriage 70A, the control unit 60 reciprocates the carriage 70A in the main scanning direction MSD (step 3, hereinafter also referred to as “stirring operation”). The order of the bubble discharging operation and the stirring operation is not limited, and the bubble discharging operation may be performed after the stirring operation. Thereafter, the control unit 60 causes the liquid to be ejected from the head 40 to record a desired image on the ejection target medium (step 4, hereinafter also referred to as “recording operation”). This flow is completed through these steps.

  When the first recording operation including the bubble discharging operation is executed according to the flowchart in FIG. 6, the recording operation is performed in a state where the bubbles in the second container 20 are reduced. Thereby, the droplet discharge device 100 is excellent in the discharge stability of the head 40 and can record a good image.

1.5.2. Second Recording Operation FIG. 6 is a flowchart showing a second recording operation including a bubble discharging operation when an inkjet printer 300 described later is used as the droplet discharge device 100. When the liquid supply system 100 having the bubble detection sensor 56 is used, the second recording operation can be performed including the bubble discharge operation according to the flow of FIG.

  As shown in the flowchart of FIG. 6, first, when the control unit 60 in the ink jet printer 300 receives an image recording command (step 11, hereinafter also referred to as “image recording command”), the bubble detection sensor 56 receives the second tube. 32 bubbles are detected (step 12, hereinafter, also referred to as “bubble detection operation”). If the bubble detection sensor 56 does not detect bubbles (NO in step 13), the control unit 60 reciprocates the carriage 70A in the main scanning direction MSD (step 14, stirring operation). Thereafter, the control unit 60 causes the liquid to be ejected from the head 40 to record a desired image on the ejection target medium (step 15, hereinafter also referred to as “recording operation”). The flow in this case ends through the above steps.

  On the other hand, when the bubble detection sensor 56 detects bubbles (YES in step 13), the control unit 60 discharges the bubbles collected in the second opening 20B of the second container 20 from the head 40 (step 16, bubble discharge operation). . Note that the bubble discharging operation in step 16 may be performed by sucking bubbles using the bubble discharging mechanism, similarly to the first recording operation.

  Next, the control unit 60 counts the number of times that the bubble discharging operation has been performed (step 17, hereinafter also referred to as “bubble discharging operation count”), and the count value of the number of bubble discharging operations is a predetermined number (for example, If less than (4 times) (NO in step 18), the flow after step 12 is executed again. And if a bubble is no longer detected from a bubble detection sensor, the control part 60 will perform said step 14 and step 15. FIG. In this way, this flow ends. Although not shown, the control unit 60 may appropriately include a counter, a determination unit, and the like.

  On the other hand, when the count value of the number of bubble discharging operations after the control unit 60 receives the image recording command is equal to or greater than a predetermined number (for example, 4 times) (YES in Step 18), the control unit 60 sends An error signal is transmitted to the part (step 19). Thereby, for example, it is possible to notify the user that a problem has occurred in the droplet discharge device 100. The flow in this case ends through the above steps. In addition, as an inconvenience of the droplet discharge device 100, for example, the occurrence of a bubble abnormality is cited. For example, the transmitter causes an error display to be displayed on a screen display unit (not shown) provided in the droplet discharge device 100, or a sound is output to a sound source transmitter (not shown) provided in the droplet discharge device 100. Can be sounded. In this way, the transmission unit can inform the user of the occurrence of an abnormality. FIG. 6 is a flow including the control unit 60 causing the transmission unit to display an error (execute step 19). However, the flow is not limited to this and may be a flow in which no error display is executed. .

  In addition, each step of Step 12, Step 13, Step 16, Step 17, and Step 18 in the flow of FIG. 6 described above can be collectively referred to as a cleaning process. As described above, the cleaning process is ended when NO in step 13 or YES in step 18.

  In the flow of FIG. 6, the stirring operation may be performed before the bubble detection operation. In this case, the stirring operation may not be performed before the recording operation. When bubbles are present at locations that are difficult to detect by the bubble detection operation (for example, bubbles staying outside the vicinity of the second opening 20B of the second container 20), if the agitation operation is performed before the bubble detection operation, the second opening 20B. It can be easily moved to the vicinity. Thereby, the bubbles in the second container 20 are effectively detected by the bubble detection sensor 56 and discharged from the head 40.

  The bubble discharge operation in the second recording operation is performed after the bubble detection sensor 56 determines the presence or absence of bubbles near the second opening 20B. For this reason, when the second recording operation is executed, the bubbles in the second container 20 are more effectively discharged from the head 40.

  The bubble discharging operation is associated with the image recording command in the same manner as the above-described first recording operation, but may be associated with other operations. The bubble discharging operation is performed when an image recording command is received. However, the present invention is not necessarily limited to this mode, and when the image recording command is not received (for example, when the apparatus is powered on or powered off) Time).

  The bubble discharge operation is a means for forcibly confirming whether or not bubble discharge is necessary (for example, an input means in a host device such as a PC connected to the droplet discharge device 100 by wire or wireless, droplet discharge) It may be executed by a forced bubble discharge button provided in the apparatus 100. In this case, the means for forcibly confirming whether or not the bubble needs to be discharged can transmit a command for executing the cleaning process to the control unit 60. When receiving an instruction to execute the cleaning process, the control unit 60 executes the process.

1.6. Applications The droplet discharge device 100 according to the present invention can be used as an inkjet printer. Hereinafter, the ink jet printer 300 according to the present embodiment will be described.

  FIG. 7 is a perspective view schematically showing the ink jet printer 300 according to the present embodiment. As shown in FIG. 7, the inkjet printer 300 according to the present embodiment includes a control unit 60, a first container 10, a first tube 30, a second container 20, a second tube 32, a head 40, The driving unit 70 and the paper feeding unit 80 can be provided.

  The first container 10, the second container 20, the head 40, the first tube 30 and the second tube 32 are the same as those in “1. Droplet ejecting device”, and thus description thereof is omitted.

  The control unit 60 can be configured using a computer having a CPU and a memory. The control unit 60 has a function of controlling the first container 10, the head 40, the driving unit 70, and the paper feeding unit 80.

  The drive unit 70 can include a carriage 70A, a drive belt 70B, and a carriage motor 70C. The drive unit 70 is connected to the control unit 60 via the flexible cable 62 and is controlled by the control unit 60. The drive unit 70 has a function of reciprocating the carriage 50A in a predetermined direction MSD. Specifically, the drive unit 70 drives the drive belt 70B connected to the carriage 70A by the power of the carriage motor 70C serving as a drive source of the carriage 70A, and reciprocates the carriage 70A in a predetermined direction MSD.

  The carriage 70A is mounted with the second container 20 and the head 40 as described in “1. Liquid droplet ejection device”. When the carriage 50A is moved in the predetermined direction MSD, droplets are appropriately ejected from the head 40 and recording on the recording paper P is performed.

  The head 40 can eject liquid using a conventionally known method such as a piezo ink jet or a thermal jet ink jet.

  The paper feed unit 70 includes a paper feed motor (not shown) serving as a drive source thereof, and a paper feed roller 72 that rotates by the operation of the paper feed motor. The paper supply unit 70 can convey the recording paper P in a direction intersecting the predetermined direction MSD.

1.7. Effect The droplet discharge device 100 according to the present embodiment has the second opening 20B at the highest position in the vertical direction on the inner wall surface of the second container 20 when bubbles are generated in the second container 20. The air bubbles can be efficiently collected in the second opening 20B. The bubbles collected in the second opening 20 </ b> B are discharged from the head 40 by being supplied to the head 40. Therefore, the head 40 of the droplet discharge device 100 according to the present embodiment is excellent in discharge stability.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 10 ... 1st container, 20 (120) ... 2nd container, 20A ... 1st opening, 20B ... 2nd opening, 22 ... Upper surface, 24 (124) ... Bottom surface, 26 (26a, 26b, 26c, 26d) ... Side surface , 30 ... 1st pipe, 32 ... 2nd pipe, 40 ... Head, 55 ... Valve, 56 ... Bubble detection sensor, 60 ... Control part, 62 ... Flexible cable, 70 ... Drive part, 70A ... Carriage, 70B ... Drive belt , 70C ... Carriage motor, 80 ... Paper feed section, 82 ... Paper feed roller, 100 ... Droplet discharge device, 123 ... Curved surface, 300 ... Inkjet printer

Claims (8)

A first container containing liquid and allowing the liquid to flow out;
A first opening through which the liquid flowing out from the first container flows in, and a second container having a second opening through which the liquid flows out;
A head from which the liquid flowing out from the second opening flows in and discharges the liquid;
Have
The second opening is a liquid droplet ejection device located at the highest position in the vertical direction on the inner wall surface of the second container. In claim 1,
Furthermore, a droplet discharge device comprising a carriage mounted with the second container and the head and reciprocating in a predetermined direction. In claim 1 or claim 2,
The inner wall surface of the second container has a vertically upward convex portion, and the second opening is located at the convex portion. In any one of Claims 1 thru | or 3,
The droplet discharge device, wherein an inner wall surface of the second container is concentrated toward the second opening. In any one of Claims 1 thru | or 4,
Furthermore, a droplet discharge device comprising a bubble discharge mechanism for discharging bubbles in the second container through the head. In claim 5,
And a pipe connecting the second opening and the head;
A detection unit for detecting bubbles inside the tube;
A control unit for controlling the bubble discharge mechanism and the detection unit;
With
The control unit starts the cleaning process at a given timing,
The control unit operates the detection unit in the cleaning process, determines the presence or absence of bubbles based on the output of the detection unit,
In the case where it is determined that there is a bubble, the control unit,
Operate the bubble discharge mechanism, and count the number of operations of the bubble discharge mechanism after starting the cleaning process,
If the count value is less than a predetermined value, the cleaning process is performed again from the operation of the detection unit.
Droplet discharge device. In claim 6,
In the cleaning process, the control unit ends the cleaning process if the count value is equal to or greater than a predetermined value. In claim 7,
Furthermore, it has a transmitter that transmits an error signal,
The control unit terminates the cleaning process and causes the transmission unit to transmit an error signal.

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