TWI510379B - An ink tank, and an ink stirring method using the ink tank - Google Patents

Description

Ink cartridge, and ink agitation method using the same

The present invention relates to an ink cartridge used in an ink ejecting apparatus which ejects ink from a nozzle of an ink jet head to print, and an ink agitation method using the ink cartridge.

In the ink ejecting apparatus which ejects ink from the nozzle of the ink jet head, the particles of the ink (pigment, metal particles) cause sedimentation, aggregation, deposition, precipitation, etc. (hereinafter referred to as sinking, etc.) in the ink cartridge.虞, and there is a drop in the concentration of the particle components in the ink cartridge.

Therefore, Patent Document 1 discloses an ink tank for an ink jet recording apparatus in which a magnetic stirrer rotor for stirring ink is provided at the bottom of the ink tank, and the ink in the ink tank can be stirred by the rotation of the magnetic stirrer rotor. . The ink cartridge for an ink jet recording apparatus disclosed in Patent Document 1 can prevent sedimentation of particles of ink which is likely to remain in the bottom portion.

Further, Patent Document 2 discloses an ink jet printer that can vibrate an ultrasonic vibrator by ultrasonic waves generated from an ultrasonic oscillator to prevent clogging of ink in the ink supply path. The ink jet printer disclosed in Patent Document 2 does not need to have a structure such as a stirrer rotor at the bottom of the ink cartridge, and can prevent clogging of the ink jet head.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. SHO 60-110458

[Patent Document 2] Japanese Patent Publication No. Sho 58-066951

In the ink cartridge for an ink jet recording apparatus disclosed in Patent Document 1, the ink of the agitator rotor or the like is mixed in the ink, which may cause a problem of clogging of the ink jet head. Further, especially in the case where the ink is a ferromagnetic body, there is also a problem that the ink tends to adhere to the magnetic stirrer rotor, making it difficult to use up.

Moreover, the driving source of the magnetic stirrer rotor must be disposed directly below the rotating magnetic stirrer rotor, thus losing the freedom of ink cartridge design. In other words, in order to prevent the sedimentation of the particle components of the ink which is likely to remain in the bottom portion, it is necessary to dispose the particles at the bottom of the ink cartridge. The magnetic stirrer rotor of the composition is provided with a drive source directly below it, so that there is also a problem that ink cannot be supplied from the bottom of the ink cartridge.

In Patent Document 2, since it is not necessary to provide a structure such as a stirrer rotor in the ink tank at the bottom of the ink cartridge, ink can be supplied from the bottom of the ink cartridge. However, since the vibration generated by the ultrasonic waves is directly transmitted to the ink in the ink cartridge, there is a problem that it is likely to cause a discharge failure of the ink jet head. Further, depending on the frequency of the ultrasonic vibration, there is a possibility that the noise is driven, and the printing accuracy is deteriorated.

The present invention has been made in view of such circumstances, and an object thereof is to provide an ink cartridge which can be used without any fear of sedimentation of particle components of ink, and which can use ink, and an ink agitation method using the ink cartridge.

In order to achieve the above object, the ink cartridge according to the first invention is stored and supplied to An inkjet head ink, characterized by comprising: a cylinder; a pipe connected as a part of the cylinder; a circulation portion that sends ink in the pipe; and a supply port that is disposed in the cylinder The lower portion of the body is supplied with ink to the above-described inkjet head; and the internal ink is circulated through the above-mentioned duct.

An ink cartridge for storing ink supplied to an inkjet head according to a first aspect of the invention includes: a cylinder; a pipe which is connected as a part of the cylinder; a circulation portion that sends ink in the pipe; and a supply port It is disposed under the barrel and supplies ink to the inkjet head. By circulating the ink inside the ink cartridge through the pipe, the possibility that the particle component of the ink settles under the ink cartridge can be reduced, and the ink of the ink cartridge can be used. Further, since no vibration is applied to the ink while circulating through the pipe, the vibration is not transmitted to the inkjet head, and it is hard to be affected by the driving noise.

According to a second aspect of the invention, in the ink cartridge according to the first aspect of the invention, the end portion of the duct is located below the other end portion, and the circulation portion causes the ink in the duct to pass from the one end portion to the other end portion. mobile.

In the second aspect of the invention, the end portion of the duct is located below the other end portion, and the circulation portion sends the ink in the duct from the one end portion to the other end portion. Thereby, ink can be sent from the one end portion located at the lower side to the other end portion located above in the duct, and the ink in the duct can be effectively stirred from the upper side to the lower side.

Further, the ink cartridge according to the third aspect of the invention is characterized in that the first or second invention includes a suction port for sucking air in an upper portion of the tubular body in a state in which a negative pressure is generated in an upper portion of the tubular body.

According to the third aspect of the invention, since the suction port for sucking the air above the cylindrical body is formed in a state in which the upper portion of the cylindrical body is in a negative pressure state, the upper portion of the cylindrical body is in a negative pressure state, and the supply of ink to the ink jet head can be stopped. And the ink in the ink tank can be continuously circulated until the sedimentation of the particle component of the ink in the lower portion of the ink cartridge is eliminated.

Further, the ink cartridge according to the fourth aspect of the invention is characterized in that the cylindrical body is formed in an annular shape, and the duct is connected to one end portion and the other end portion as one of the annular portions. .

According to the fourth aspect of the invention, the tubular body is formed in an annular shape, and the duct is connected to the one end portion and the other end portion as one of the annular portions. Therefore, the inner ink can be reliably circulated through the duct, and the particle composition of the ink can be prevented from being excessively worried. The ink is settled under the ink tank, and the ink is used up.

Then, in order to achieve the above object, an ink cartridge according to a fifth aspect of the present invention is characterized in that: the ink is supplied to the inkjet head, and comprises: a cylinder; a pipe connecting the upper portion and the lower portion of the cylinder; and a circulation portion; And sending the ink in the pipe; and the supply port is disposed under the cylinder and supplying ink to the inkjet head; and circulating the ink inside through the pipe.

According to a fifth aspect of the invention, in an ink cartridge for storing ink supplied to an inkjet head, comprising: a cylinder; a pipe connecting the upper portion and the lower portion of the cylinder; and a circulation portion for discharging the ink in the pipe; And a supply port which is disposed under the cylinder and supplies ink to the inkjet head. By circulating the ink inside the ink cartridge through the pipe, the possibility that the particle component of the ink settles under the ink cartridge can be reduced, and the ink of the ink cartridge can be used.

Next, in order to achieve the above object, the ink agitation method according to the sixth aspect of the invention is characterized in that the ink cartridge stored in the ink cartridge is stirred by using the ink cartridge according to any one of the first to fifth inventions.

The ink cartridge used in the sixth invention includes: a cylinder (cylinder); a duct which is connected as a part of the cylinder (connecting the upper portion and the lower portion of the cylinder); and a circulation portion which is sent out into the duct The ink; and a supply port which is disposed under the cylinder (cylinder) and supplies ink to the inkjet head. By circulating the ink inside the ink cartridge through the pipe, the possibility that the particle component of the ink settles in the lower portion of the ink cartridge can be reduced, and the ink of the ink cartridge can be used.

According to the above configuration, the invention includes: a cylinder; a duct which is connected as a part of the cylinder; a circulation portion that sends ink in the duct; and a supply port that is disposed under the cylinder and that has ink Supply to the inkjet head. By circulating the ink inside the ink cartridge through the pipe, the possibility that the particle component of the ink settles in the lower portion of the ink cartridge can be reduced, and the ink of the ink cartridge can be used.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic view showing a schematic configuration of an ink ejecting apparatus including an ink cartridge according to an embodiment of the present invention. The ink ejection device 1 shown in Fig. 1 includes an inkjet head 2, an ink cartridge 3, a vacuum pump 35, a compressed air supply source 36, and a control device 37. The ink jet head 2 is formed on one surface of the plurality of nozzles 21 for ejecting the ink 20, and is pressed by a piezoelectric element or the like. The ink 20 in the nozzle 21 is ejected, and the ink 20 is ejected from the opening 22 of the nozzle 21. The piezoelectric element or the like is driven and controlled by the control device 37. The size of the ink jet head 2 is, for example, about 120 mm long, about 10 mm wide, and about 100 mm high. The number of the nozzles 21 differs depending on the object to be printed by ejecting the ink 20, and is several tens to hundreds of them, and the distance between the nozzles 21 is wide, and is about 1 mm. Further, the arrangement of the openings 22 of the nozzles 21 may be one line or a plurality of lines. Further, the entirety of the opening portions 22 of the plurality of nozzles 21 does not have to be continuously arranged.

The ink cartridge 3 stores the ink 20 supplied to the inkjet head 2. The ink 20 used in the ink ejection device 1 is, for example, a pigment-based ink, an ink containing metal particles (electrode material, that is, Au, Ag, Cu, Pd, Ni) or conductive particles, and a particle component (pigment) is dispersed in the liquid. , metal particles, etc.). Further, the ink 20 may contain ceramics, a resin, or the like in addition to metal particles or the like. Further, the viscosity of the ink 20 is preferably a low viscosity of 40 mPa‧s or less, and particularly preferably a viscosity of 10 mPa‧s to 25 mPa‧s. The capacity of the ink tank 3 is, for example, 50 mL.

Fig. 2 is a schematic view showing a configuration example of an ink cartridge 3 according to an embodiment of the present invention. As shown in FIG. 2, the ink cartridge 3 includes a cylinder 5, a duct 4, and a duct pump (circulation portion) 6. Further, a supply port 7 as an inlet for supplying the ink 20 to the ink jet head 2 is provided at a lower portion of the cylindrical body 5. The cylindrical body 5 is formed in an annular shape, and is cut off from the vicinity of the flow path leading to the ink jet head 2 to the flow path leading to the opening and closing valves 33, 34 in the flow direction of the ink 20 indicated by an arrow. Part of 4. The inside of the tube 4 through the ink 20 can be connected as a part of the cylindrical body 5 to the cut portion. Will flow to the inkjet head 2 The connecting portion between the tubular body 5 and the duct 4 near the road serves as the one end portion 42, and the connecting portion between the tubular body 5 and the duct 4 located above the one end portion 42 serves as the other end portion 41. In this case, the length of the circulation path of the ink 20 becomes substantially equal to the length of the ring of the ink cartridge. Further, when the circulation path is in the form of an annular shape, the retention of the ink 20 can be suppressed.

The cylinder 5 is formed of polypropylene, SUS, glass, or the like. Further, the duct 4 is a duct of a tantalum system, and is not particularly limited as long as it is a duct which is deformed according to the pressing force from the outside. In the present embodiment, the inner diameter of the duct 4 is set to, for example, 3 mm.

In the middle of the pipe 4, a pipe pump 6 is provided as a circulation portion of the ink 20 in the delivery pipe 4. The action of the pipeline pump 6 is controlled by the control unit 37. Fig. 3 is a schematic view showing a configuration example of the duct pump 6 of the ink cartridge 3 according to the embodiment of the present invention.

The duct pump 6 is provided with a duct 4 having elasticity along the inner circumference of the frame 63 which is formed into a substantially circular shape on the inner circumference, and is disposed at a position opposed to each other by the arrangement of the rotor 61 which rotates in the same direction as the flow direction of the ink 20. One of the pair of rollers 62 presses the pipe 4. By the rotation of the rotor 61, the pair of rollers 62 are moved to be connected to the duct 4, and the ink 20 in the duct 4 is pressed along the duct 4, whereby the ink 20 is sent. In the example of Fig. 3, since the rotor 61 rotates in the clockwise direction, the ink 20 is sucked from one end portion 42 of the duct 4 and sent to the other end portion 41.

After the passage of the pair of rollers 62, the portion of the pipe 4 that is pressed is restored to its original state by the restoring force, and the volume is restored to its original state. The ink 20 is continuously sucked from the one end portion 42 by the volume of the duct 4 being restored to its original shape.

The pipeline pump 6 is suitable for transporting ink 20 as it does not use a valve. A viscous liquid with a high degree of maintainability that replaces only the only consumable, pipe 4. Of course, it is not limited to the duct pump 6 having the configuration shown in FIG. 3, and it is only necessary to provide an actuator that can circulate the ink 20 from the outside of the duct 4 as a circulation portion.

According to the present embodiment, the circulation path of the ink 20 is formed in a closed circuit shape by the tubular body 5 and the duct 4, and the ink 20 is pressed from the outer side of the deformable duct 4 to circulate. If it is such a configuration, the ink 20 There is also less possibility of generating pollutants inside.

Returning to Fig. 1, a vacuum path 31 for generating a negative pressure state (1 to 3 kPa) inside the ink cartridge 3 is formed by attaching air to the upper portion of the cylinder 5 to the upper portion of the cylinder 5 of the ink cartridge 3, and A gas supply path 32 for supplying compressed air (compressed gas). In order to prevent the ink 20 from dripping constantly from the nozzle 21, a suction port 30 for sucking air above the ink tank 3 is provided on the upper portion of the sealed ink cartridge 3, and the upper portion of the cylinder 5 is sucked from the suction port 30. Air creates a negative pressure state. Thereby, the supply of the ink 20 to the inkjet head 2 can be stopped by the negative pressure, and the ink 20 in the ink cartridge 3 can be continuously circulated until the sedimentation of the particle component of the ink 20 at the lower portion of the ink cartridge 3 is eliminated.

On the other hand, when the ink 20 is discharged by a larger amount than the amount ejected from the nozzle 21 at the time of printing (at the time of cleaning), the opening and closing valve 33 for the negative pressure provided in the vacuum path 31 is closed, and the opening and closing valve 33 is opened. The opening and closing valve 34 for the compressed air of the gas supply path 32 supplies compressed air into the ink cartridge 3. By supplying compressed air into the ink cartridge 3, the ink 20 in the ink cartridge 3 can be pushed out from the opening portion 22 of the nozzle 21, and the ink 20 can be discharged in a larger amount than that ejected from the nozzle 21 at the time of printing (clearing action). In addition, the opening and closing valve 33 for negative pressure It is connected to the vacuum pump 35 via a pressure regulating valve. Further, the on-off valve 34 for compressed air is connected to the compressed air supply source 36 via a pressure regulating valve. Further, the opening and closing valve 33 for the negative pressure and the opening and closing of the opening and closing valve 34 for the compressed air are controlled by the control device 37.

Below the inkjet head 2, a stage 72 on which the to-be-printed object 73 is placed is disposed. The printed matter 73 is adsorbed to the stage 72 and fixed so as not to move relative to the stage 72. The stage 72 is movable in the three-axis direction and aligned with the position of the ink 20 ejected from the nozzle 21 of the ink-jet head 2 to move the placed printed matter 73. In addition, the movement of the platform 72 is controlled by the control unit 37.

The stirring method using the ink 20 of the ink cartridge 3 according to the present embodiment will be described based on Fig. 1 . First, the opening and closing valve 34 for the compressed air provided in the air supply path 32 is closed, and the opening and closing valve 33 for the negative pressure provided in the vacuum path 31 is opened, so that the upper portion of the cylindrical body 5 is in a negative pressure state. In this state, the duct pump 6 is activated, and by pressing the duct 4, the ink 20 in the duct 4 is sent out from the one end portion 42 to the other end portion 41.

By ejecting the ink 20 in the duct from the one end portion 42 to the other end portion 41, a cycle of clockwise rotation in the ink cartridge 3 is generated, whereby the ink 20 in the ink cartridge 3 can be stirred, and the particle composition of the ink 20 can be suppressed. Settling and so on. Since the corner portion is not present in the ink cartridge 3, even if the particle component of the ink 20 is sedimented or the like, the particle component does not stay.

The opening and closing valve 34 for the compressed air provided in the gas supply path 32 is opened, and the opening and closing valve 33 for the negative pressure provided in the vacuum path 31 is appropriately closed and stored in a state where the sedimentation of the particle component of the ink 20 is eliminated. The ink 20 in the ink cartridge 3 is supplied to the inkjet head 2. That is, by opening the on-off valve 33 The condition is adjusted to adjust the degree of suction, and the ink 20 necessary for printing can be supplied to the inkjet head 2.

In this way, the ink cartridge 3 can circulate the ink 20 inside through the duct 4, so that the possibility that the particle component of the ink 20 settles inside the ink cartridge 3 is reduced, and the ink 20 of the ink cartridge 3 can be used. Further, since it is not necessary to provide another path for circulating the ink 20, the circulation path of the ink 20 becomes short. Moreover, since the circulation path of the ink 20 is closed, there is less possibility of generating contaminants in the ink 20.

Further, the one end portion 42 is located below the other end portion 41, and the vacuum pump 6 sends the ink 20 in the duct 4 from the lower side to the upper side. Therefore, the inside of the annular ink tank 3 can be circulated, so that the ink 20 in the ink tank 3 can be efficiently stirred.

Needless to say, the shape of the cylindrical body 5 is not limited to the one shown in Figs. 1 and 2, and may be, for example, a substantially "mouth" shape. FIG. 4 is a schematic view showing a configuration example in a case where the ink cartridge 3 according to the embodiment of the present invention is formed into a cylindrical body 5 having a substantially "mouth" shape. As shown in Fig. 4, the cylindrical body 5 is formed in a substantially "mouth" shape, and cuts off about 1/4 of the flow direction of the ink 20 indicated by an arrow from the vicinity of the flow path to the ink jet head 2. . The inside of the tube 4 through the ink 20 can be connected as a part of the cylindrical body 5 to the cut portion. The connecting portion between the tubular body 5 and the duct 4 in the vicinity of the flow path to the ink jet head 2 is referred to as an end portion 42, and the joint portion between the tubular body 5 and the duct 4 located above the one end portion 42 is referred to as the other end portion 41. .

In the middle of the pipe path 4, a pipe pump 6 as a circulation portion for discharging the ink 20 in the pipe 4 is provided. The action of the pipeline pump 6 is controlled by the control unit 37. Similarly to FIG. 1 and FIG. 2, by ejecting the ink 20 in the duct 4 from the one end portion 42 to the other end portion 41, a cycle of clockwise rotation is generated in the ink cartridge 3, whereby the ink in the ink cartridge 3 can be stirred. 20, sedimentation of the particle component of the ink 20, and the like can be suppressed.

Further, for example, a configuration in which the cylindrical body 5 is provided instead of the cylindrical body 5 may be employed. Fig. 5 is a schematic view showing another configuration example of the ink cartridge 3 according to the embodiment of the present invention. As shown in FIG. 5, the ink cartridge 3 includes a cylinder 5 in place of the cylinder, a pipe 4, and a pipe pump (circulation portion) 6. The duct 4 is connected to the upper and lower portions of the cylinder 5. The connecting portion between the lower portion of the cylinder 5 and the duct 4 is referred to as an end portion 42, and the connecting portion between the upper portion of the cylindrical body 5 and the duct 4 is referred to as the other end portion 41.

A pipe pump 6 as a circulation portion of the ink 20 in the delivery pipe 4 is provided in the middle of the duct 4. The action of the pipeline pump 6 is controlled by the control unit 37. Similarly to FIG. 1, FIG. 2 and FIG. 4, by ejecting the ink 20 in the duct 4 from the one end portion 42 to the other end portion 41, the ink 20 in the ink cartridge 3 is convected, thereby stirring the ink cartridge 3 therein. The ink 20 can suppress sedimentation of the particle component of the ink 20 and the like.

Further, for example, the shape of the cylindrical body 5 may be a cylindrical shape. Fig. 6 is a schematic view showing a configuration example in a case where the ink cartridge 3 according to the embodiment of the present invention is formed into a cylindrical tubular body. As shown in Fig. 6, the cylindrical body 5 is formed in a cylindrical shape, and a portion of substantially 1/4 of the cylindrical body 5 is cut along the central axis. The ink supply 20 is connected to the cut portion by a portion of the inner tube 4 as a portion of the cylindrical body 5. The connection portion between the tubular body 5 and the duct 4 on the right side of FIG. 6 is referred to as an end portion 42, and the connection portion between the tubular body 5 on the left side and the duct 4 is referred to as the other end portion 41.

A pipe pump 6 as a circulation portion of the ink 20 in the delivery pipe 4 is provided in the middle of the duct 4. The action of the pipeline pump 6 is controlled by a control unit 37. Similarly to FIG. 1, FIG. 2, FIG. 4, and FIG. 5, by ejecting the ink 20 in the duct 4 from the one end portion 42 to the other end portion 41, the ink 20 in the ink cartridge 3 can be made under the ink cartridge 3. Convection is generated so that the ink 20 in the ink tank 3 can be stirred, and sedimentation or the like of the particle components of the ink 20 can be suppressed.

The pipe 4 is connected as a part of the tubular body 5, and is not limited to the lower portion of the cut portion, and may be upper, and is not limited to being connected by one pipe 4, or may be connected by a plurality of pipes 4. This is because the ink 20 in the ink tank 3 can be stirred. If it is desired to improve the effect of suppressing sedimentation or the like on the lower portion of the ink cartridge 3, it is preferable to connect the duct 4 to the lower portion. If the ink 20 in the ink cartridge 3 is to be effectively convected, it is preferable to connect the duct 4 to the upper side.

As described above, according to the present embodiment, by circulating the ink 20 inside the ink cartridge 3 via the duct 4, it is possible to reduce the possibility that the particle component of the ink 20 is deposited on the lower portion of the ink cartridge 3, and the ink of the ink cartridge 3 can be used. 20. Moreover, since the circulation path of the ink 20 is closed, there is less possibility of generating contaminants in the ink 20.

Further, the present invention is not limited to the above-described embodiments, and various modifications, substitutions, and the like can be made within the scope of the gist of the invention. For example, a concentration sensor capable of detecting the concentration of the ink 20 may be attached to the ink cartridge 3 to continuously circulate the ink 20 until the sedimentation of the particle component of the ink 20 or the like is eliminated, that is, until the concentration reaches a certain level.

Further, a plurality of ink cartridges 3 may be connected in parallel in advance, and sequentially from the ink cartridge 3 which has eliminated the sedimentation of the particle components of the ink 20, etc. The flow path of the first 2 is connected. Thereby, it is not necessary to wait for the printing operation until the sedimentation of the particle component of the ink 20 is eliminated, and the ink 20 supplied from the ink tank 3 in a usable state can be accepted, so that printing can be performed at all times.

1‧‧‧Ink ejection device

2‧‧‧Inkjet head

3‧‧‧Ink box

4‧‧‧ Pipes

5‧‧‧Cylinder

6‧‧‧Pipeline pump

7‧‧‧ supply port

20‧‧‧Ink

21‧‧‧ nozzle

22‧‧‧ Openings

30‧‧ ‧ suction port

31‧‧‧vacuum path

32‧‧‧ gas supply path

33‧‧‧Opening and closing valve

34‧‧‧Opening and closing valve

35‧‧‧vacuum pump

36‧‧‧Compressed air supply

37‧‧‧Control device

41‧‧‧Other end

42‧‧‧One end

61‧‧‧Rotor

62‧‧‧roller

63‧‧‧ frame

72‧‧‧ platform

73‧‧‧Printed matter

Fig. 1 is a schematic block diagram showing an ink ejecting apparatus including an ink cartridge according to an embodiment of the present invention.

Fig. 2 is a schematic view showing a configuration example of an ink cartridge according to an embodiment of the present invention.

Fig. 3 is a schematic view showing the configuration of a pipe pump of an ink cartridge according to an embodiment of the present invention.

Fig. 4 is a schematic view showing a configuration example in a case where the ink cartridge according to the embodiment of the present invention is formed into a substantially "mouth" shaped cylinder.

Fig. 5 is a schematic view showing another configuration example of the ink cartridge according to the embodiment of the present invention.

Fig. 6 is a schematic view showing a configuration example in a case where the ink cartridge according to the embodiment of the present invention is formed into a cylindrical tubular body.

2‧‧‧Inkjet head

3‧‧‧Ink box

4‧‧‧ Pipes

5‧‧‧Cylinder

6‧‧‧Pipeline pump

7‧‧‧ supply port

20‧‧‧Ink

30‧‧ ‧ suction port

33‧‧‧Opening and closing valve

34‧‧‧Opening and closing valve

41‧‧‧Other end

42‧‧‧One end

Claims (8)

An ink cartridge for storing ink supplied to an inkjet head, comprising: a cylinder; a pipe connected as a part of the cylinder; and a circulation portion for discharging ink in the pipe; and The supply port is provided in the lower portion of the cylindrical body, and supplies ink to the ink jet head; and the internal ink is circulated through the duct. The ink cartridge of claim 1, wherein one end of the duct is located further below the other end, and the circulating portion moves the ink in the duct from the one end to the other end. An ink cartridge according to claim 1, which comprises a suction port for sucking air of the upper portion of the cylindrical body in order to generate a negative pressure state on the upper portion of the cylindrical body. An ink cartridge according to claim 2, which comprises a suction port for sucking air in an upper portion of said cylinder for generating a negative pressure state on said upper portion of said cylinder. The ink cartridge according to any one of claims 1 to 4, wherein the cylindrical body is formed in an annular shape, and the duct is connected to one end portion and the other end portion as one of the annular portions. An ink cartridge for storing ink supplied to an inkjet head, characterized by comprising: a cylinder; a pipe connecting the upper portion and the lower portion of the cylinder; a circulation portion for discharging ink in the pipe; and a supply port disposed at a lower portion of the cylinder and supplying ink to the inkjet a head; and the inner ink is circulated through the above-mentioned pipe. An ink agitation method, characterized in that the ink stored in the ink cartridge is stirred using the ink cartridge according to any one of claims 1 to 4 and 6. An ink agitating method characterized by using the ink cartridge of claim 5 to agitate the ink stored in the ink cartridge.