JP2012111079A - Liquid discharge device, and liquid discharge method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize printed image quality by making the density of a liquid discharged from a nozzle uniform.SOLUTION: A liquid discharge device includes: a liquid storage portion which stores the liquid and has a plurality of outlets in different positions in a vertical direction; a plurality of flow paths which are provided correspondingly to the plurality of outlets respectively and in which the liquids flowing out from the outlets flow; a liquid joining portion which has a plurality of inlets provided correspondingly to the plurality of flow paths respectively and in which the liquids flowing in from each of the inlets are joined to each other; and a head having the nozzle which discharges the liquid joined at the liquid joining portion to a medium.

Description

  The present invention relates to a liquid ejection apparatus and a liquid ejection method.

  As an example of a liquid ejecting apparatus, an ink jet printer that prints an image by ejecting a liquid such as ink onto various media such as paper and film is known. The ink jet printer includes a storage unit that stores a liquid and a head that includes a nozzle that discharges the liquid onto a medium. When the amount of liquid in the head decreases due to liquid discharge, the liquid is replenished from the storage portion (for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-246908

  In this inkjet printer, when the unused state continues for a long time, the liquid stored in the storage unit may settle. And if a liquid settles, a density | concentration difference will arise by the upper side and lower side in an accommodating part. As a result, an image printed using such settled liquid has an unstable image quality.

  The present invention has been made in view of such circumstances, and an object of the present invention is to improve the stability of print image quality by making the concentration of the liquid discharged from the nozzles as uniform as possible.

The main invention for solving the above problems is:
A liquid container that contains the liquid and has a plurality of outlets at different positions in the vertical direction;
A plurality of flow paths that are provided corresponding to each of the plurality of outlets, and through which the liquid flowing out from the outlets flows;
A plurality of inflow ports provided corresponding to each of the plurality of flow paths, and a liquid merging portion where the liquid flowing in from each of the inflow ports merges;
A head having a nozzle for discharging the liquid merged by the liquid merge section to a medium;
A liquid ejecting apparatus comprising:

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is a schematic diagram illustrating a configuration of a liquid ejection apparatus 1. FIG. 2 is a block diagram illustrating a configuration of the liquid ejection apparatus 1. FIG. FIG. 4 is a diagram illustrating a configuration of an ink supply unit 35. It is a figure for demonstrating the confluence | merging of an ink. 6 is a diagram illustrating another configuration of the ink supply unit 35. FIG.

  At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

That is, a liquid storage unit that stores liquid and has a plurality of outlets at different positions in the vertical direction;
A plurality of flow paths that are provided corresponding to each of the plurality of outlets, and through which the liquid flowing out from the outlets flows;
A plurality of inflow ports provided corresponding to each of the plurality of flow paths, and a liquid merging portion where the liquid flowing in from each of the inflow ports merges;
A head having a nozzle for discharging the liquid merged by the liquid merge section to a medium;
A liquid ejecting apparatus comprising:
According to such a liquid ejecting apparatus, the liquid in the liquid storage part is joined by the liquid joining part, so that the concentration of the liquid ejected from the nozzle can be made as uniform as possible and the stability of the print image quality can be improved. .

In addition, such a liquid ejection device,
The liquid junction is
A first merging portion for merging the liquid flowing in from each of the plurality of inlets;
A diversion part for diverting the liquid merged by the first merge part;
A second merging portion for remerging the liquid diverted by the divergence portion;
It is good also as having.
According to such a liquid ejection device, it is possible to more actively mix the liquid that has flowed out of the liquid container.

In addition, a liquid storage unit that stores liquid and has a plurality of outlets at different positions in the vertical direction;
A plurality of flow paths that are provided corresponding to each of the plurality of outlets, and through which the liquid flowing out from the outlets flows;
A plurality of inflow ports provided corresponding to each of the plurality of flow paths, and a liquid merging portion where the liquid flowing in from each of the inflow ports merges;
A head having a nozzle for discharging the liquid merged by the liquid merge section to a medium;
A liquid discharge method comprising discharging a liquid onto the medium using a liquid discharge apparatus comprising:
According to such a liquid ejection method, the liquid in the liquid storage unit is merged by the liquid merging unit, so that the concentration of the liquid ejected from the nozzle can be made as uniform as possible and the stability of the print image quality can be improved. .

=== First Embodiment ===
Hereinafter, the liquid ejection apparatus 1 according to the first embodiment of the present invention will be described.

<<< Regarding Configuration Example of Liquid Discharge Device 1 >>>
A configuration example of the liquid ejection apparatus 1 will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of the liquid ejection apparatus 1. FIG. 2 is a block diagram of the liquid ejection apparatus 1.

In the following description, when referring to “up and down direction” and “left and right direction”, the direction indicated by the arrow in FIG. 1 is used as a reference. In addition, the “front-rear direction” refers to a direction orthogonal to the paper surface in FIG.
In the present embodiment, a description will be given using a paper or a film wound in a roll shape (hereinafter referred to as roll paper (continuous paper)) as a medium on which the liquid ejection apparatus 1 records an image.

  Furthermore, in the present embodiment, an explanation will be given using ink (for example, pigment ink) as an example of the liquid used by the liquid ejection apparatus 1 to record an image on a medium. The pigment ink is obtained by dispersing pigment particles as a pigment in a solvent. In this pigment ink, the pigment particles may settle when left for a long time.

  As shown in FIGS. 1 and 2, the liquid ejection apparatus 1 according to the present embodiment includes a transport unit 20 as an example of a transport unit, and a transport path along which the transport unit 20 transports the roll paper 2. The feeding unit 10, a platen 29 as an example of a medium support unit, and a winding unit 90, and a head unit 30 for performing printing in the printing region R on the transport path, and ink. An ink supply unit 35 for supplying ink, a carriage unit 40 as an example of a head moving unit, a heater unit 70 as an example of a heat supply unit, and a blower unit 80 for sending air to the roll paper 2 on the platen 29. The controller 60 which controls these units and controls the operation as the liquid ejection apparatus 1 and the detector group 50 are provided.

  The feeding unit 10 feeds the roll paper 2 to the transport unit 20. The feeding unit 10 includes a winding shaft 18 around which the roll paper 2 is wound and rotatably supported, a relay roller 19 for winding the roll paper 2 fed from the winding shaft 18 and guiding the roll paper 2 to the transport unit 20; have.

  The transport unit 20 transports the roll paper 2 sent by the feeding unit 10 along a preset transport path. As shown in FIG. 1, the transport unit 20 includes a relay roller 21 that is positioned horizontally to the right of the relay roller 19, a relay roller 22 that is positioned obliquely downward to the right when viewed from the relay roller 21, and the relay roller 22. 1st conveyance roller 23 located in the upper right direction as viewed from the platen 29 (upstream side in the conveyance direction) and a right side as viewed from the first conveyance roller 23 (downstream in the conveyance direction as viewed from the platen 29). The second transport roller 24, the reverse roller 25 positioned vertically downward as viewed from the second transport roller 24, the relay roller 26 positioned rightward as viewed from the reverse roller 25, and upward as viewed from the relay roller 26. And a delivery roller 27 which is positioned.

The relay roller 21 is a roller that winds the roll paper 2 sent from the relay roller 19 from the left side and loosens it downward.
The relay roller 22 is a roller that winds the roll paper 2 sent from the relay roller 21 from the left side and conveys it obliquely upward to the right.

  The first transport roller 23 includes a first drive roller 23a driven by a motor (not shown), and a first driven roller 23b arranged to face the first drive roller 23a with the roll paper 2 interposed therebetween. have. The first transport roller 23 is a roller that pulls up the roll paper 2 slacked downward and transports it to the printing region R facing the platen 29. The first transport roller 23 is configured to temporarily stop transport during a period in which image printing is performed on a portion of the roll paper 2 on the print region R. In addition, when the first driven roller 23b rotates as the first drive roller 23a rotates by the drive control of the controller 60, the transport amount of the roll paper 2 positioned on the platen 29 (the length of the portion of the roll paper) Is adjusted).

  As described above, the transport unit 20 has a mechanism for transporting the portion of the roll paper 2 wound between the relay rollers 21 and 22 and the first transport roller 23 by slacking it downward. The slackness of the roll paper 2 is monitored by the controller 60 based on a detection signal from a slack detection sensor (not shown). Specifically, when a portion of the roll paper 2 slackened between the relay rollers 21 and 22 and the first transport roller 23 is detected by the slack detection sensor, a tension of an appropriate magnitude is applied to the portion. Therefore, the transport unit 20 can transport the roll paper 2 in a relaxed state. On the other hand, when the portion of the roll paper 2 that has been loosened is not detected by the slack detection sensor, an excessive amount of tension is applied to the portion, and therefore the transport of the roll paper 2 by the transport unit 20 is temporarily performed. And the tension is adjusted to an appropriate level.

  The second transport roller 24 includes a second drive roller 24a driven by a motor (not shown), and a second driven roller 24b disposed so as to face the second drive roller 24a with the roll paper 2 interposed therebetween. have. The second transport roller 24 is a roller that transports the portion of the roll paper 2 on which the image is recorded by the head unit 30 in the horizontal right direction along the support surface of the platen 29 and then transports it vertically downward. Thereby, the conveyance direction of the roll paper 2 is changed. The second driven roller 24b rotates as the second drive roller 24a is driven to rotate by the drive control of the controller 60, whereby a predetermined amount given to the portion of the roll paper 2 located on the platen 29 is obtained. Tension is adjusted.

The reversing roller 25 is a roller that wraps the roll paper 2 sent from the second conveying roller 24 from the upper left side and conveys it diagonally upward to the right.
The relay roller 26 is a roller that winds the roll paper 2 sent from the reversing roller 25 from the lower left side and conveys it upward.
The delivery roller 27 winds the roll paper 2 sent from the relay roller 26 from the lower left side and sends it to the take-up unit 90.

  As described above, the roll paper 2 moves sequentially through the rollers, whereby a transport path for transporting the roll paper 2 is formed. The roll paper 2 is intermittently conveyed along the conveyance path by the conveyance unit 20 in units of areas corresponding to the printing areas R.

The head unit 30 is for ejecting ink onto a portion of the roll paper 2 that has been fed into the printing region R on the transport path (on the platen 29) by the transport unit 20. The head unit 30 has a head 31.
The head 31 has a nozzle row composed of a plurality of nozzles # 1 to # 180 for each color such as yellow (Y), magenta (M), cyan (C), and black (K) on the lower surface thereof. .

  The nozzles # 1 to # 180 of each nozzle row are arranged in a straight line along the direction intersecting the transport direction of the roll paper 2. Each nozzle row is arranged in parallel with a space between each other along the moving direction (scanning direction) of the head 31. Each nozzle # 1 to # 180 is provided with a piezo element (not shown) as a drive element for ejecting ink droplets. When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts according to the expansion and contraction of the piezo element, and the ink corresponding to the contraction is ejected from the nozzles # 1 to # 180 of each color as ink droplets.

  The ink supply unit 35 is for supplying ink to the head unit 30 when the amount of ink in the head unit 30 is reduced due to the ejection of ink by the head 31, and a plurality of ink supply units are provided for each ink color. Is provided. The ink supply unit 35 is connected to the head unit 30 (head 31) via an ink supply tube. For this reason, the head 31 can perform image printing by discharging the ink supplied from the ink supply unit 35 toward the portion of the roll paper 2 that has been transported from the nozzle onto the platen 29 and stopped. it can. The specific configuration of the ink supply unit 35 will be described in detail later.

  The carriage unit 40 is for moving the head 31. The carriage unit 40 includes a guide rail 41 extending in the left-right direction (indicated by a two-dot chain line in FIG. 1), a carriage 42 supported so as to reciprocate in the left-right direction (movement direction) along the guide rail 41, And a motor shown in the figure.

  The carriage 42 is configured to move integrally with the head 31 by driving a motor (not shown). The position of the carriage 42 (the head 31 or each nozzle row) on the guide rail 41 (the position in the left-right direction) is determined by the rising edge and the falling edge in the pulse signal output from the encoder provided in the motor (not shown) by the controller 60. It can be obtained by detecting and counting this edge.

  Then, when cleaning the head 31 after image printing, the carriage 42 moves together with the head 31 along the guide rail 41 to the upstream side in the transport direction (upstream in the transport direction as viewed from the platen 29). It stops at the home position HP for cleaning (see FIG. 1).

  A cleaning unit (not shown) is provided at the home position HP. This cleaning unit has a cap, a suction pump, and the like. When the carriage 42 is positioned at the home position HP, a cap (not shown) is in close contact with the lower surface (nozzle surface) of the head 31. When the suction pump (not shown) is operated with the cap in close contact, the ink in the head 31 is sucked together with the thickened ink and paper powder. In this way, the clogged nozzle recovers from the non-ejection state, thereby completing the head cleaning.

  The platen 29 supports the part of the roll paper 2 located in the printing region R on the conveyance path and heats the part. As shown in FIG. 1, the platen 29 is provided in correspondence with the printing region R on the conveyance path, and in a region along the conveyance path between the first conveyance roller 23 and the second conveyance roller 24. Has been placed. The platen 29 can heat the portion of the roll paper 2 by receiving supply of heat generated by the heater unit 70.

  The heater unit 70 is for heating the roll paper 2 and has a heater (not shown). This heater has a nichrome wire, and the nichrome wire is arranged inside the platen 29 so as to be at a fixed distance from the support surface of the platen 29. For this reason, when the heater is energized, the nichrome wire itself generates heat, and heat can be conducted to the portion of the roll paper 2 located on the support surface of the platen 29. Since this heater is configured by incorporating a nichrome wire in the entire area of the platen 29, heat can be uniformly conducted to the portion of the roll paper 2 on the platen 29. In the present embodiment, the portion of the roll paper 2 is uniformly heated so that the temperature of the portion of the roll paper 2 on the platen is 45 ° C. Thereby, the ink landed on the part of the roll paper 2 can be dried.

  The blower unit 80 includes a fan 81 as an example of a blower and a motor (not shown) that rotates the fan 81. The fan 81 rotates to send wind to the roll paper 2 on the platen 29 and dry the ink landed on the roll paper 2. As shown in FIG. 1, a plurality of fans 81 are provided on an openable / closable cover (not shown) provided on the main body. Each fan 81 is positioned above the platen 29 when the cover is closed, and faces the support surface of the platen 29 (the roll paper 2 on the platen 29).

  The winding unit 90 is for winding the roll paper 2 (image-printed roll paper) sent by the transport unit 20. This take-up unit 90 is fed from the relay roller 91 that is rotatably supported by the relay roller 91 for winding the roll paper 2 sent from the feed roller 27 from the upper left side and conveying it to the lower right side. And a take-up drive shaft 92 for taking up the roll paper 2.

  The controller 60 is a control unit for controlling the liquid ejection apparatus 1. As shown in FIG. 2, the controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 is for transmitting and receiving data between the host computer 110 which is an external device and the liquid ejecting apparatus 1. The CPU 62 is an arithmetic processing device for controlling the entire liquid ejection device 1. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like. The CPU 62 controls each unit by a unit control circuit 64 according to a program stored in the memory 63.

  The detector group 50 is for monitoring the state in the liquid ejection apparatus 1. For example, the detector group 50 is attached to a transport roller and is used for control such as transport of a medium, and detects the presence or absence of a transported medium. And a linear encoder for detecting the position of the carriage 42 (or head 31) in the moving direction (left-right direction).

<<< Configuration of Ink Supply Unit 35 >>>
Here, a configuration example of the ink supply unit 35 will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram illustrating a configuration example of the ink supply unit 35. FIG. 4 is a diagram illustrating ink merging using a cross section of the ink supply tube.

  The ink supply unit 35 is for supplying ink to the head unit 30, and a plurality of ink supply units 35 are provided for each ink color. That is, each ink supply unit 35 supplies ink of a different color to the corresponding head 31. In the following, since each ink supply unit 35 has the same configuration, the ink supply unit 35 that supplies yellow ink (Y) will be described as an example.

  The ink supply unit 35 includes an ink cartridge IC, a sub ink tank ST as an example of a liquid container, a first ink supply tube 34 as an example of a flow path through which ink flows from the ink cartridge IC to the sub ink tank ST, It has a tube unit TY as an example of a liquid junction, and a second ink supply tube 36 as an example of a flow path through which ink flows from the sub ink tank ST to the tube unit TY.

<Ink cartridge IC>
The ink cartridge IC stores ink to be supplied to the head unit 30. As shown in FIG. 3, the ink cartridge IC has an outlet ICo that is connected to the first ink supply tube 34 and is provided at a lower portion in the vertical direction. The ink cartridge IC is configured to be detachable from the liquid ejection apparatus main body.

<Sub ink tank ST>
The sub ink tank ST temporarily stores ink supplied from the ink cartridge IC to the head unit 30. As shown in FIG. 3, the sub ink tank ST is connected to the inlet STi provided at the upper portion in the vertical direction to which the first ink supply tube 34 is connected, and a plurality of second ink supply tubes 36 are connected to each other. And a plurality of outlets STo provided at different positions in the direction.

  The sub ink tank ST is fixed inside the liquid ejection device. That is, unlike the ink cartridge IC, the sub ink tank ST cannot be attached to and detached from the liquid ejection apparatus main body.

  Thus, since the sub ink tank ST is fixed in the inside, even if the head 31 moves in the movement direction together with the carriage 42, the sub ink tank ST does not interlock with the movement of the head 31. However, ink replenishment from the sub ink tank ST to the head 31 is reliably performed by interposing an ink supply tube having a length considering the amount of movement of the head 31 between the sub ink tank ST and the head 31. It has come to be.

  Here, when the ink stored in the sub ink tank ST is left for a long time, the ink may settle. Such sedimentation causes a density difference between the upper side and the lower side in the vertical direction in the sub ink tank ST as shown in FIG. In particular, when the ink is a pigment ink, the density difference due to the sedimentation appears remarkably. And when an image is printed using such settled ink, it will gradually change from a dark color image to a light color image with the passage of time, leading to a decrease in print image quality. Become.

  On the other hand, in the present embodiment, the tube unit TY, which will be described later, is interposed between the sub ink tank ST and the head unit 30, and the inks having different densities are merged to improve the uniformity of the ink density. I am letting. This point will be described in detail later.

  Note that if the ink stored in the sub ink tank ST settles, the ink stored in the ink cartridge IC also naturally settles. However, since the ink cartridge IC is configured to be detachable from the main body of the liquid ejection apparatus, the user can remove the ink sedimentation by removing the ink cartridge IC from the main body and shaking it up and down.

<First ink supply tube 34>
As shown in FIG. 3, the first ink supply tube 34 connects the outlet ICo of the ink cartridge IC and the inlet STi of the sub ink tank ST to flow ink. A valve 34a and a supply pump 34b are provided on the flow path.

The valve 34a is for opening and closing the flow path of the first ink supply tube 34, and opens and closes in response to a control signal from the controller 60 when the ink cartridge IC is replaced. Since the valve 34a is a check valve, the ink does not flow back from the sub ink tank ST to the ink cartridge IC.
The supply pump 34b sucks ink in the ink cartridge IC in response to a control signal from the controller 60 and sends it into the sub ink tank ST.

  In addition, the supply of ink from the ink cartridge IC into the sub ink tank ST is performed by a supply pump (not shown) instead of the supply pump 34b that guides compressed air in response to a control signal from the controller 60 into the ink cartridge IC. The ink pack in the ink cartridge may be compressed.

<Second ink supply tube 36>
As shown in FIG. 3, a plurality of the second ink supply tubes 36 are provided corresponding to the outlets STo of the sub ink tank ST, and the sub ink tank ST and the tube unit TY are connected to flow ink. Is for. A valve 36a and a supply pump 36b are provided on the flow path.

  The valve 36 a is for opening and closing the flow path of the second ink supply tube 36, and performs an opening and closing operation based on a control signal from the controller 60 when ink is supplied to the head unit 30. Since the valve 36a is a check valve, ink does not flow backward from the tube unit TY to the sub ink tank ST.

  The supply pump 36b sucks the ink in the sub ink tank ST in accordance with the amount of ink in the head unit 30 and sends it into the tube unit TY. The ink supply operation by the supply pump 36 b is performed based on a control signal from the controller 60. The controller 60 controls the operation of the supply pump 36b so as to suck out the same amount of ink from each outlet STo. As a result, the same amount of each ink that has passed through each of the second ink supply tubes 36 flows into the tube unit TY, so that the respective inks are mixed by the same amount, thereby mixing more uniformly. Is possible.

  In addition, for supplying ink from the sub ink tank ST to the tube unit TY, a tube pump (not shown) can be used instead of the supply pump 36b. The tube pump described in JP 2001-301195 A can be used. As shown in FIG. 2 of the publication, hollow tubes 103 are arranged in an α (alpha) shape, for example. The roller 4 moves along the tube 103 so as to crush the tube 103, so that the ink in the cap 17 is sucked.

<Tube unit TY>
The tube unit TY is provided between the sub ink tank ST and the head unit 30 and joins the inks supplied from the sub ink tank ST via the plurality of second ink supply tubes 36.

  As shown in FIG. 3, the tube unit TY includes a merging tube unit TY1 as an example of a first merging portion, a divergence tube unit TY2 as an example of a divergence portion, and a re-use as an example of a second merging portion. A merging tube unit TY3. The tube unit TY has a plurality of inflow ports provided at the end portion on the upper side in the vertical direction and an outflow port provided at the end portion on the lower side in the vertical direction.

  Here, since the ink stored in the sub ink tank ST settles after a long time has elapsed, as shown in FIG. 3, there is a density difference between the upper side and the lower side in the vertical direction in the sub ink tank ST. . In such a case, since the sub ink tank ST has a plurality of outlets STo at different positions in the vertical direction, each ink having a different density can flow out from each outlet STo. The tube unit TY can improve the uniformity of the ink density by combining the inks with different densities supplied from the sub ink tank ST so that the inks with different densities are mixed with each other. . The specific configuration of the tube unit TY is as follows.

  The inks having different concentrations that have flowed out from the respective outlets STo of the sub ink tank ST flow through the respective second ink supply tubes 36 and flow in from the upper end in the vertical direction of the tube unit TY. When it flows in, it reaches the merging tube unit TY1.

  As shown in FIG. 3, the tube unit TY1 for merging flows inks having different densities by flowing the inks having different densities flowing from the upper side in the vertical direction through the second ink supply tube 36, respectively. Are sequentially mixed in pairs, and finally the mixed ink is discharged. As a result of this merging, as shown in FIG. 4A, the ink that finally flows out in the merging tube TY1 (ink after merging) is in a state where the inks before merging are somewhat mixed. Flows in a state where the inks do not mix sufficiently due to the viscosity of the ink itself, etc. (a state where adjacent inks form a boundary in the ink supply tube and are grouped for each ink) Tend. Therefore, it is not possible to improve the uniformity of the ink density simply by using the merging tube TY1.

  Next, as shown in FIG. 3, the diversion tube unit TY2 causes the combined ink that has flowed out from the merging tube unit TY1 to flow in, so that the combined ink is sequentially branched into two. In order to spill four parts.

  As described above, in the diversion tube unit TY2, the ink after the merging is intentionally diverged, as described above, the ink that has passed through the merging tube unit TY1 is sufficiently mixed with inks having different concentrations. This is because the inks having different densities are mixed more positively by causing the inks to flow again in the subsequent re-merging tube unit TY3 because they tend to flow without being present. As a result, such a tendency is alleviated and the ink density can be further uniformed.

  Next, as shown in FIG. 3, the recombination tube unit TY3 mixes each of the inks in sequence by passing each of the four inks flowing out from the diversion tube unit TY2 in sequence. Finally, the mixed ink is discharged. As a result of this merging, the ink that finally flows out into one in the re-merging tube unit TY3 has more inks with different densities than the ink that flows out from the merging tube unit TY1. It will flow in a mixed state. In this way, it is possible to further improve the uniformity of the ink density by repeating the ink merging and branching.

  Then, after passing through the recombination tube unit TY3, the ink with uniform density is supplied to the head unit 30 (head 31).

<<< Effectiveness of Liquid Discharge Device 1 According to the Present Embodiment >>>
As described above, the liquid ejection apparatus 1 according to the present embodiment accommodates ink and corresponds to each of the sub ink tank ST having a plurality of outlets STo at different positions in the vertical direction and the plurality of outlets STo. A plurality of second ink supply tubes 36 through which ink flowing out from the outlet STo flows, and a plurality of inlets provided corresponding to the plurality of second ink supply tubes 36, respectively. And a tube unit TY into which the ink flowing from each of the inlets merges. As a result, the inks having different densities supplied from the sub ink tank ST are merged in the tube unit TY, so that the inks having different densities are mixed with each other, thereby improving the uniformity of the ink density. Can do. For this reason, even when the ink settles down after being left for a long time, an image with improved density uniformity can be printed, so that the stability of the print image quality can be improved.

  Further, when ink sedimentation occurs, the ink cartridge IC is configured to be detachable from the liquid ejecting apparatus main body, so that the user can remove the ink cartridge IC from the main body and shake it up and down. Ink settling can be eliminated. On the other hand, since the sub ink tank ST cannot be detached from the liquid ejection apparatus main body, it cannot perform such maintenance work. Therefore, the invention according to the present embodiment is effective when ink sedimentation occurs in the sub ink tank ST.

=== Second Embodiment ===
Next, the liquid ejection apparatus 1 according to the second embodiment of the present invention will be described.

<<< Regarding Configuration Example of Liquid Discharge Device 1 >>>
Similarly to the liquid ejection device 1 according to the first embodiment described above, the liquid ejection device 1 according to the second embodiment includes a transport unit 20, a feeding unit 10, a platen 29, a winding unit 90, and a head. The unit 30, the ink supply unit 35, the carriage unit 40, the heater unit 70, the air blowing unit 80, the controller 60, and the detector group 50 are included.
However, in the liquid ejection apparatus 1 according to the second embodiment, the configuration of the ink supply unit 35 is different from that of the liquid ejection apparatus 1 according to the first embodiment.
Therefore, the ink supply unit 35 having a configuration different from that of the first embodiment will be specifically described.

<<< About Ink Supply Unit 35 >>>
Here, a configuration example of the ink supply unit 35 in the second embodiment will be described with reference to FIG. FIG. 5 is a diagram illustrating a configuration example of the ink supply unit 35 in the second embodiment.

The ink supply unit 35 is for supplying ink to the head unit 30, and a plurality of ink supply units 35 are provided for each ink color. That is, each ink supply unit 35 supplies ink of a different color to the corresponding head 31. In the following, since each ink supply unit 35 has the same configuration, the ink supply unit 35 that supplies yellow ink (Y) will be described as an example.
The ink supply unit 35 includes an ink cartridge IC as an example of a liquid storage unit, a sub ink tank ST as an example of a liquid merging unit, and a first channel as an example of a flow path through which ink flows from the ink cartridge I to the sub ink tank ST. One ink supply tube 34 and a second ink supply tube 36 as an example of a flow path through which ink flows from the sub ink tank ST toward the head unit 30 are provided.

<Ink cartridge IC>
Unlike the first embodiment, the ink cartridge IC in the second embodiment is an example of a liquid container.

The ink cartridge IC stores ink to be supplied to the head unit 30. As shown in FIG. 5, the ink cartridge IC has a plurality of outlets ICo connected to the first ink supply tubes 34 and provided at different positions in the vertical direction. The ink cartridge IC is configured to be detachable from the liquid ejection apparatus main body.
Here, the ink stored in the ink cartridge IC may be left for a long time to cause the ink to settle. Such sedimentation causes a density difference between the upper side and the lower side in the vertical direction in the ink cartridge IC as shown in FIG. In particular, when the ink is a pigment ink, the density difference due to the sedimentation appears remarkably. And when an image is printed using such settled ink, it will gradually change from a dark color image to a light color image with the passage of time, leading to a decrease in print image quality. Become.

On the other hand, in this embodiment, the ink density is made uniform by combining the inks having different densities in the sub ink tank ST. This point will be described in detail later.
For this reason, in order to eliminate the sedimentation of the ink, the maintenance work that has been conventionally required such that the user removes the ink cartridge IC from the liquid ejection apparatus main body and shakes it up and down becomes unnecessary.

<Sub ink tank ST>
Unlike the first embodiment, the sub ink tank ST in the second embodiment is an example of a liquid junction.

The sub ink tank ST temporarily stores ink replenished from the ink cartridge IC to the head unit 30. As shown in FIG. 5, the sub ink tank ST has a plurality of inlets STi provided at the upper end in the vertical direction and a plurality of first ink supply tubes 34 correspondingly connected thereto, and a second ink supply. And an outlet STo provided at the lower end in the vertical direction to which the tube 36 is connected.
The sub ink tank ST is fixed inside the liquid ejection device. That is, unlike the ink cartridge IC, the sub ink tank ST cannot be attached to and detached from the liquid ejection apparatus main body.

  Thus, since the sub ink tank ST is fixed in the inside, even if the head 31 moves in the movement direction together with the carriage 42, the sub ink tank ST does not interlock with the movement of the head 31. However, ink replenishment from the sub ink tank ST to the head 31 is reliably performed by interposing an ink supply tube having a length considering the amount of movement of the head 31 between the sub ink tank ST and the head 31. It has come to be.

  Here, since the ink stored in the ink cartridge IC settles after a long time, as shown in FIG. 5, there is a density difference between the upper side and the lower side in the vertical direction in the ink cartridge IC. In such a case, the ink cartridge IC has a plurality of outlets ICo at different positions in the vertical direction, so that each ink having a different density can flow out from each outlet ICo. The sub ink tank ST allows the inks having different densities supplied from the ink cartridge IC to flow in (influence) from the respective inlets STi provided at the ends on the upper side in the vertical direction. By mixing different inks with each other, it is possible to improve the uniformity of the ink density supplied to the head unit 30.

<First ink supply tube 34>
As shown in FIG. 5, a plurality of first ink supply tubes 34 are provided corresponding to the outlet ICo of the ink cartridge IC, and the outlet ICo of the ink cartridge IC and the inlet STi of the sub ink tank ST are connected. It is for connecting and flowing ink. A valve 34a and a supply pump 34b are provided on the flow path.

  The valve 34a opens and closes the flow path of the first ink supply tube 34, and responds to a control signal from the controller 60 when the ink cartridge IC is replaced or when ink is supplied to the sub ink tank ST. Open and close. Since the valve 34a is a check valve, the ink does not flow back from the sub ink tank ST to the ink cartridge IC.

  In response to a control signal from the controller 60, the supply pump 34b sucks the ink in the ink cartridge IC and sends it into the sub ink tank ST. The ink supply operation by the supply pump 34 b is performed based on a control signal from the controller 60. The controller 60 controls the operation of the supply pump 34b so as to suck out the same amount of ink from each outlet ICo. As a result, the same amount of each ink that has passed through each first ink supply tube 34 flows into the sub ink tank ST, so that the respective inks are mixed by the same amount, thereby mixing more uniformly. It becomes possible.

  In addition, the supply of ink from the ink cartridge IC into the sub ink tank ST is performed by a supply pump (not shown) instead of the supply pump 34b that guides compressed air in response to a control signal from the controller 60 into the ink cartridge IC. The ink pack in the ink cartridge may be compressed.

<Second ink supply tube 36>
As shown in FIG. 5, the second ink supply tube 36 connects the sub ink tank ST and the head unit 30 to flow ink. The ink whose density is uniformed by merging in the sub ink tank ST flows through the second ink supply tube 36 and is supplied to the head 31.

<<< Effectiveness of Liquid Discharge Device 1 According to the Present Embodiment >>>
As described above, the liquid ejection apparatus 1 according to the present embodiment accommodates ink and is provided corresponding to each of the ink cartridge IC having a plurality of outlets ICo at different positions in the vertical direction and the plurality of outlets ICo. A plurality of first ink supply tubes 34 through which the ink flowing out from the outlet ICo flows, and a plurality of inlets STi provided corresponding to the plurality of first ink supply tubes 34, respectively. And a sub ink tank ST into which the ink flowing from each of the inlets STi joins. As a result, the inks having different densities supplied from the ink cartridge IC are merged into the sub ink tank ST, so that the inks having different densities are mixed with each other, thereby improving the uniformity of the ink density. Can do. For this reason, even when ink sedimentation occurs due to standing for a long time, an image with improved density uniformity can be printed, so that the stability of the print image quality can be improved.

  In addition, since the maintenance work such as the user removing the ink cartridge IC from the main body and shaking it up and down in order to eliminate the ink settling state as in the prior art becomes unnecessary, the ink settling occurs in the ink cartridge IC. Therefore, the invention according to the present embodiment is effective.

=== Other Embodiments ===
Although the present embodiment is mainly described with respect to a liquid discharge apparatus, disclosure of a liquid discharge method and the like is also included. Further, the present embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<Liquid ejection device>
In the above embodiment, the ink jet printer has been described as an example of the liquid ejection device, but the present invention is not limited to this. For example, a liquid ejection device that ejects liquid other than ink may be used. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the liquid discharged from the said liquid discharge apparatus, and also includes what pulls a tail in granular shape, tear shape, and a thread form. The liquid here may be any material that can be discharged by the liquid discharge device. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. Further, representative examples of the liquid include ink and liquid crystal as described in the above embodiment. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks. As a specific example of the liquid ejection device, for example, a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter or the like in a dispersed or dissolved form. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. In addition, a transparent resin liquid such as UV curable resin is used to form a liquid ejection device that ejects lubricating oil pinpoint to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid discharge apparatus that discharges an acid or alkali or the like to etch the substrate or the like may be employed. The present invention can be applied to any one of these liquid ejection devices.

<Tube unit>
In the above embodiment, the tube unit TY having the merging tube unit TY1, the diverting tube unit TY2, and the remerging tube unit TY3 has been described as an example, but is limited to this configuration. is not. For example, in addition to these, a tube unit TY having a redistribution tube unit or a rejoining tube unit may be used. In other words, the number of repetitions of merging and diversion may be changed as appropriate. As the merge and diversion are repeated, it is possible to further improve the uniformity of the ink density.
In the above embodiment, two sets of inks are mixed in the merging tube unit TY1 and the remerging tube unit TY3. However, the present invention is not limited to this. In the branching tube unit TY2, the branch flow path of the tube may be changed as appropriate.

1 liquid ejection device, 2 roll paper, 10 feeding unit,
18 roll axis, 19 relay roller, 20 transport unit,
21 relay roller, 22 relay roller,
23 1st conveyance roller, 24 2nd conveyance roller,
25 reversing roller, 26 relay roller, 27 delivery roller,
29 platens, 30 head units, 31 heads,
35 ink supply unit, 40 carriage unit,
41 guide rail, 42 carriage, 50 detector group,
60 controller, 70 heater unit,
80 blower unit, 81 fan, 90 take-up unit,
91 relay roller, 92 winding drive shaft,
110 Host computer

Claims (3)

A liquid container that contains the liquid and has a plurality of outlets at different positions in the vertical direction;
A plurality of flow paths that are provided corresponding to each of the plurality of outlets, and through which the liquid flowing out from the outlets flows;
A plurality of inflow ports provided corresponding to each of the plurality of flow paths, and a liquid merging portion where the liquid flowing in from each of the inflow ports merges;
A head having a nozzle for discharging the liquid merged by the liquid merge section to a medium;
A liquid ejection apparatus comprising: The image recording apparatus according to claim 1,
The liquid junction is
A first merging portion for merging the liquid flowing in from each of the plurality of inlets;
A diversion part for diverting the liquid merged by the first merge part;
A second merging portion for remerging the liquid diverted by the divergence portion;
A liquid ejecting apparatus comprising: A liquid container that contains the liquid and has a plurality of outlets at different positions in the vertical direction;
A plurality of flow paths that are provided corresponding to each of the plurality of outlets, and through which the liquid flowing out from the outlets flows;
A plurality of inflow ports provided corresponding to each of the plurality of flow paths, and a liquid merging portion where the liquid flowing in from each of the inflow ports merges;
A head having a nozzle for discharging the liquid merged by the liquid merge section to a medium;
A liquid discharge method comprising discharging a liquid onto the medium using a liquid discharge apparatus comprising:

Images