JP2010058326A - Defoaming mechanism and liquid jet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique of eliminating air bubbles in a liquid in a liquid jet apparatus. <P>SOLUTION: The defoaming mechanism, for eliminating air bubbles from the liquid circulated in the liquid jet apparatus, includes a defoaming chamber and a reverse flow suppressing part. The defoaming chamber to capture the air bubbles in the liquid has a top surface, a bottom surface, and a side surface extended in the vertical direction. The reverse flow suppressing part makes the defoaming chamber communicate with a liquid supply passage in the liquid jet apparatus and suppresses a reverse flow of the air bubbles from the defoaming chamber to the liquid supply passage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for removing bubbles from a liquid flowing in a liquid ejecting apparatus.

  In an ink jet printer, if bubbles occur in ink in an ink supply path from an ink supply unit such as an ink cartridge to a recording head, printing defects such as missing dots may be caused. Therefore, it is required to remove bubbles (defoaming) from the ink. As a mechanism for performing this defoaming, a chamber (defoaming chamber) for temporarily storing ink and trapping bubbles is adjacent to a decompression chamber via a gas-permeable partition, and the pressure in the decompression chamber is adjusted. A mechanism for removing bubbles trapped in the defoaming chamber by lowering the pressure is proposed (see Patent Document 1 below).

JP 2006-95878 A

  However, the conventional defoaming mechanism has a problem that bubbles in the ink cannot be sufficiently removed. Such a problem may occur not only in an ink jet printer but also in any liquid ejecting apparatus that ejects liquid such as lubricating oil or resin liquid.

  An object of the present invention is to provide a technique for removing bubbles in a liquid in a liquid ejecting apparatus.

  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 forms or application examples.

  [Application Example 1] A defoaming mechanism for removing bubbles from a liquid flowing in a liquid ejecting apparatus, which has an upper surface, a bottom surface, and a side surface extending in a vertical direction, for capturing bubbles in the liquid A defoaming chamber, and a backflow suppression unit that communicates the defoaming chamber and the liquid supply path in the liquid ejecting apparatus and suppresses the backflow of the bubbles from the defoaming chamber to the liquid supply path, Defoaming mechanism.

  Since the defoaming mechanism of Application Example 1 has the backflow suppression unit that suppresses the backflow of bubbles from the defoaming chamber to the liquid supply path, the backflow of bubbles from the defoaming chamber to the liquid supply path is suppressed. And a large amount of bubbles can be captured and removed in the defoaming chamber.

  Application Example 2 In the defoaming mechanism according to Application Example 1, the backflow suppressing unit has a flow path having a smaller cross-sectional area than the cross-sectional area of the liquid supply path.

  By doing in this way, the cross-sectional area of the flow path in a backflow suppression part can be made small, and the penetration | invasion of the bubble from a defoaming chamber to a backflow suppression part can be suppressed.

  Application Example 3 In the defoaming mechanism according to Application Example 1 or Application Example 2, the backflow suppressing unit has a cross-sectional flow path having a longitudinal direction and a short direction.

  By doing in this way, as the shape of the flow path of the backflow suppression unit, the length in the short direction is made smaller than the diameter (or long axis) of the cross section (circle or ellipse) of the bubble to the backflow suppression unit. While suppressing the intrusion of bubbles, the cross-sectional area of the backflow suppressing portion (flow path) can be increased to improve the liquid flowability.

  [Application Example 4] In the defoaming mechanism according to any one of Application Examples 1 to 3, the communication part may be any one of the upper surface, the bottom surface, and the side surface. Defoaming chamber connected to the defoaming chamber.

  By doing in this way, a connection part can be formed easily compared with the structure which a communicating part connects in the corner of a defoaming chamber.

  Application Example 5 In the defoaming mechanism according to Application Example 4, in the defoaming chamber, the communication portion is connected to the defoaming chamber above the half of the height of the side surface among the side surfaces.

  In this way, the liquid flowing into the defoaming chamber can be directed downward, while the bubbles in the liquid can be directed upward by buoyancy, and separation of the liquid and bubbles can be achieved in a short time. it can.

  Application Example 6 A liquid ejecting apparatus including the defoaming mechanism according to any one of Application Examples 1 to 5.

  By doing so, a large amount of bubbles can be removed from the liquid flowing through the ejection device in a short time, and liquid ejection defects such as missing dots can be suppressed.

A. First embodiment:
A1. Device configuration:
FIG. 1 is an explanatory diagram showing a schematic configuration of a printer 500 including a carriage 100 as a defoaming mechanism of the present invention. The printer 500 is an ink jet printer that can eject inks of four colors (black, cyan, magenta, and yellow). The printer 500 includes an ink cartridge IC1 for black ink, an ink cartridge IC2 for cyan ink, an ink cartridge IC3 for magenta ink, an ink cartridge IC4 for yellow ink, a carriage 100, a recording head 150, a guide rod 260, A platen 270, four ink supply pumps 220a, 220b, 220c, and 220d, and a pressure reducing pump 300 are provided.

  The printer 500 is a so-called off-carriage type printer in which four ink cartridges IC1 to IC4 are mounted on the printer body side. The ink cartridge IC1 is connected to the carriage 100 via a tube t1, an ink supply pump 220a, and a tube t11. Similarly, the ink cartridge IC2 is connected to the tube t2, the ink supply pump 220b and the tube t12, the ink cartridge IC3 is connected to the tube t3, the ink supply pump 220c and the tube t13, and the ink cartridge IC4 is connected to the tube t4. The ink supply pump 220d and the tube 14 are connected to the carriage 100, respectively. The decompression pump 300 is connected to the carriage 100 via a tube t5. Each of the ink cartridges IC1 to IC4 is attached to a main body frame (not shown) of the printer 500 by a cartridge holder (not shown).

  The ink supply pump 220a supplies the black ink in the ink cartridge IC1 to the carriage 100. Similarly, the ink supply pump 220b carries cyan ink in the ink cartridge IC2, the ink supply pump 220c carries magenta ink in the ink cartridge IC3, and the ink supply pump 220d carries yellow ink in the ink cartridge IC4. 100. The decompression pump 300 is used in common for each color (black, cyan, magenta, yellow).

  The guide rod 260 is arranged along the longitudinal direction (direction parallel to the Z axis) of the platen 270 above the platen 270 (+ Y direction). The carriage 100 is supported so as to be movable in the longitudinal direction of the platen 270 along the guide rod 260, and is driven by a carriage motor (not shown) via a timing belt (not shown). The recording head 150 is disposed on the bottom surface of the carriage 100 and ejects ink droplets downward (−Y direction) from a number of nozzles (not shown) as the carriage 100 reciprocates in the longitudinal direction. At this time, the recording paper P is fed in the + X direction on the platen 270 by a paper feeding mechanism (not shown), and an image or the like is formed on the recording paper P.

  FIG. 2A is an explanatory diagram illustrating a state of the carriage 100 and the recording head 150 during ink ejection. FIG. 2A schematically shows functions of the carriage 100. FIG. 2A shows a function related to the supply of black ink, but the same applies to the function related to the supply of ink of other colors.

  The carriage 100 includes a filter chamber 60, an air chamber 87, a first pressure chamber 77, a first pressure regulating valve 71, a defoaming chamber 92, a decompression chamber 80, a second pressure chamber 89, and a second pressure regulating chamber. A pressure valve 81, three internal flow paths 62, 64, 79 through which ink flows and a negative pressure supply path 358 are provided.

  The filter chamber 60 includes a filter 61 inside and is used for removing impurities by filtering inflowed ink. The filter chamber 60 communicates with the tube t11 through the internal flow path 62. Further, the filter chamber 60 communicates with a valve chamber 70 described later via an internal flow path 64. The atmosphere chamber 87 communicates with the atmosphere via the atmosphere communication hole 99.

  The first pressure chamber 77 is used to temporarily store black ink and adjust the pressure in the ink supply path in the carriage 100. The first pressure chamber 77 is adjacent to the atmospheric chamber 87 with a partition wall 88b that is a ceiling portion interposed therebetween. The partition wall portion 88b has flexibility and can be displaced in the vertical direction. The partition wall portion 88b can be formed of, for example, a film made of synthetic resin, rubber, or the like and a cantilever (not shown) thin plate member that can be displaced together with the film. The first pressure chamber 77 includes an ink inlet 76 and communicates with a valve chamber 70 described later via the ink inlet 76. The first pressure chamber 77 communicates with the defoaming chamber 92 through the internal flow path 79.

  The first pressure regulating valve 71 is used to control the distribution of black ink. The first pressure regulating valve 71 includes a valve chamber 70, a valve body 72, a pressure adjustment spring 73, a seal member 75, and a support rod 74. The valve chamber 70 communicates with the internal flow path 64. The valve body 72 is disposed in the valve chamber 70 and is urged toward the sealing position by the pressure adjusting spring 73. The valve body 72 is displaceable between an open position where the first pressure chamber 77 and the valve chamber 70 are in communication with each other and a sealing position where the first pressure chamber 77 and the valve chamber 70 are out of communication. Specifically, the ink is discharged from the first pressure chamber 77, thereby pushing down the valve body 72 (the pressing force of the support rod 74 by the partition wall portion 88b (atmospheric pressure) and the pressure in the first pressure chamber 77). However, when it becomes larger than the force which pushes up the valve body 72 (the pressure in the valve chamber 70 and the urging force of the pressure adjusting spring 73), it is displaced toward the open position. Further, when ink flows into the first pressure chamber 77 and the force for pushing down the valve body 72 becomes smaller than the force for pushing up the valve body 72, the ink is displaced toward the sealing position. In the example of FIG. 2A, the valve body 72 is located at the open position. The seal member 75 is disposed on the upper surface of the valve body 72 and seals the ink from flowing from the valve chamber 70 to the first pressure chamber 77 when the valve body 72 is disposed at the sealing position. The support rod 74 is disposed across the valve chamber 70 and the first pressure chamber 77, one end is joined to the valve body 72, and the other end is joined to the partition wall portion 88 b of the first pressure chamber 77.

  The defoaming chamber 92 is used for temporarily storing ink flowing from the internal flow path 79 and capturing bubbles. The defoaming chamber 92 includes a filter 93 inside. The defoaming chamber 92 communicates with the internal flow path 79 on the upper side of the filter 93. The defoaming chamber 92 is also in communication with the ink discharge channel 95. The filter 93 has a function of making it difficult for air bubbles mixed in the ink supply path to pass therethrough and trapping air bubbles at the ceiling of the defoaming chamber 92.

  The decompression chamber 80 is used to remove bubbles from the ink trapped in the defoaming chamber 92 by utilizing the pressure difference between the defoaming chamber 92. The decompression chamber 80 is disposed above the defoaming chamber 92 and is adjacent to the defoaming chamber 92 through a partition wall 90 having gas permeability. In addition, as the partition part 90, it can comprise using the member which consists of polyacetal, a polypropylene, polyphenylene ether etc., for example.

  The second pressure chamber 89 is used to supply the negative pressure supplied from the decompression pump 300 to the decompression chamber 80. The second pressure chamber 89 is disposed above the decompression chamber 80 and communicates with the tube t5 via the negative pressure supply path 358. The second pressure chamber 89 communicates with the decompression chamber 80 through the communication hole 86. The second pressure chamber 89 is adjacent to the atmospheric chamber 87 with the partition wall portion 88a that is a ceiling portion interposed therebetween. In addition, the partition part 88a has the same structure as the above-mentioned partition part 88b. However, the partition wall portion 88a and the partition wall portion 88b are not in contact with each other and can be independently displaced.

  The second pressure regulating valve 81 is disposed across the second pressure chamber 89 and the decompression chamber 80 and is used to control the supply of negative pressure from the second pressure chamber 89 to the decompression chamber 80. The second pressure regulating valve 81 has the same configuration as the first pressure regulating valve 71 described above. That is, the second pressure regulating valve 81 includes a valve body 82, a pressure adjustment spring 83, a seal member 85, and a support rod 84. The valve body 82 can be displaced between an open position where the second pressure chamber 89 and the decompression chamber 80 are in communication with each other and a sealing position where the second pressure chamber 89 and decompression chamber 80 are not in communication. Is being energized. In the example of FIG. 2 (A), the valve body 82 is disposed at the open position. The seal member 85 seals the communication hole 86 and maintains the negative pressure in the decompression chamber 80 when the valve body 82 is disposed at the sealing position. The support rod 84 has one end joined to the valve body 82 and the other end joined to the partition wall portion 88a.

  The recording head 150 is disposed on the bottom surface of the carriage 100 and ejects ink toward the recording paper P (FIG. 1). The recording head 150 includes a nozzle plate 152 and an ink discharge channel 154. The ink discharge channel 154 communicates with the ink discharge channel 95 of the carriage 100 and guides the ink supplied from the defoaming chamber 92 to the nozzle plate 152. The nozzle plate 152 includes a number of nozzles (not shown).

  The printer 500 described above corresponds to the liquid ejecting apparatus in the claims.

A2. Ink supply operation in the carriage 100:
When ink is ejected from a large number of nozzles (not shown) provided on the nozzle plate 152 shown in FIG. 2A and the ink is consumed, the pressure in the first pressure chamber 77 decreases due to the reduction of the ink. Then, the pressure in the first pressure chamber 77 becomes lower than the pressure (atmospheric pressure) in the atmospheric chamber 87, and the partition wall 88 b is deflected to the inside of the first pressure chamber 77 and displaced downward by this pressure difference. At this time, the valve body 72 is pushed down via the support rod 74. When the urging force of the pressure adjustment spring 73 is overcome and the valve body 72 is positioned at the open position, the ink inlet 76 is opened and the ink flows into the first pressure chamber 77.

  FIG. 2B is an explanatory diagram illustrating the state of the carriage 100 and the recording head 150 after ink has flowed into the first pressure chamber 77 from the opened ink inlet 76. When ink flows into the first pressure chamber 77 and the chamber pressure increases, the partition wall portion 88b is displaced upward. Accordingly, when the valve body 72 moves to the sealing position again, the inflow of ink into the first pressure chamber 77 is stopped, and the supply of ink to the recording head 150 is stopped. As described above, the printer 500 is configured such that the consumed amount of ink appropriately flows into the recording head 150 by opening and closing the first pressure regulating valve 71 according to the consumption of ink.

A3. Defoaming action:
The negative pressure generated by the decompression pump 300 (FIG. 1) is supplied to the second pressure chamber 89 via the tube t5 and the negative pressure supply path 358 (FIG. 2A). At this time, the partition wall portion 88a is deflected to the inside of the second pressure chamber 89 and displaced downward by the pressure difference between the pressure in the second pressure chamber 89 (negative pressure) and the pressure in the atmosphere chamber 87 (atmospheric pressure). The valve body 82 is pushed down via the support rod 84. When the valve body 82 is positioned at the open position, the communication hole 86 is opened and negative pressure is supplied to the decompression chamber 80. Then, the pressure in the defoaming chamber 92 becomes lower than the pressure in the defoaming chamber 92, and the bubbles (gas) BL trapped in the ceiling portion of the defoaming chamber 92 are between the decompression chamber 80 and the defoaming chamber 92. The pressure difference passes through the partition wall 90 and flows into the decompression chamber 80.

A4. Detailed configuration of the carriage 100:
FIG. 3 is a perspective view showing a detailed configuration of the carriage 100. In FIG. 3, for the sake of illustration, only the configuration related to the supply of black ink is shown. The carriage 100 having the above-described configuration (function) has a configuration in which a plurality of thin plate members (hereinafter referred to as “plates”) are stacked in the vertical direction (Y-axis). In these plurality of plates, the shape of the plane perpendicular to the stacking direction (lamination surface: XZ plane) is a rectangle having the same size. In FIG. 3, the details of the partition plate 10 among the plurality of stacked plates are illustrated, and the other plates are omitted.

  The partition plate 10 includes a partition wall portion 90, a flow path forming portion 52, and a flow path forming portion 66. The flow path forming part 52 is a groove formed on the back surface of the partition plate 10. When the partition plate 10 and a plate (not shown) that contacts the back surface are laminated, a part of the internal flow path 79 is formed. The flow path 79a to be formed is formed. One end of the flow path forming portion 52 (groove) is connected to the defoaming chamber 92, and the other end is connected to the through hole 51 that penetrates the partition plate 10. The flow path forming portion 66 is a groove formed on the surface of the partition plate 10, and is formed when the partition plate 10 and a plate (not shown) that abuts on the surface (the upper surface of the stacked surfaces) are stacked. The internal flow path 62 is formed. Note that one end of the flow path forming portion 66 is connected to a flow hole 65 provided on the back surface of the partition plate 10.

A5. Communication state between the internal flow path 79 and the defoaming chamber 92:
FIG. 4 is a cross-sectional view showing details of the AA cross section shown in FIG. In the example of FIG. 4, in addition to the partition plate 10 shown in FIG. 3, other three plates are shown.

  A decompression chamber plate 11 is disposed adjacently above the partition plate 10. In addition, a first defoaming chamber plate 12 is disposed adjacent to the lower side of the partition plate 10. A second defoaming chamber plate 13 is arranged adjacent to the lower side of the first defoaming chamber plate 12.

  The decompression chamber plate 11 includes a recess 21 whose opening is an opening and a through hole 53 that penetrates in the thickness direction (the direction along the Y axis). The partition plate 10 includes a recess 20 formed in the lower portion of the partition wall portion 90, the above-described through hole 51, and the above-described flow path forming portion 52. The recess 20 is a quadrangular prism-shaped depression having a rectangular cross section (XZ cross section). The first defoaming chamber plate 12 includes a through hole 22 penetrating in the thickness direction and a flow path forming portion 54. The flow path forming portion 54 is a groove formed on the upper surface of the first defoaming chamber plate 12 and extending in a direction parallel to the X axis. The second defoaming chamber plate 13 includes a recess 23. The recess 23 has a mortar shape having an opening provided on the upper surface of the second defoaming chamber plate 13 and a bottom surface smaller than the opening. The bottom surface BS of the recess 23 is provided with a through-hole penetrating in the thickness direction used as the ink discharge channel 154.

  When the four plates 10 to 13 described above are stacked, a decompression chamber 80, a defoaming chamber 92, an internal flow path 79, and a flow path 79a are formed. Specifically, the decompression chamber 80 is formed by the recess 21 and the partition wall 90. Further, a defoaming chamber 92 is formed by the recess 20, the through hole 22, and the recess 23. Further, the two through holes 53 and 51 communicate with each other to form a part of the internal flow path 79. Further, the flow path forming part 52 and the flow path forming part 54 are arranged to face each other, and a flow path 79a is formed between the two flow path forming parts 52 and 54.

  The flow path 79a includes a main flow path part 79b and a communication part 79c. The main flow path portion 79 b is a flow path extending in a direction parallel to the X axis, and one end thereof is connected to the through hole 51. The communication part 79c is formed as an upward flow path from the main flow path part 79b to the defoaming chamber 92, and connects the defoaming room 92 and the main flow path part 79b. Here, one end of the communication portion 79 c is connected to the side wall of the defoaming chamber 92. In the example of FIG. 4, the bubble BL is captured above the location where the communication portion 79 c and the side wall of the defoaming chamber 92 are connected. As a location where the communication part 79c and the side wall of the defoaming chamber 92 are connected, it is preferable that the defoaming chamber 92 is located above half the height of the defoaming chamber 92. By doing so, the ink flowing into the defoaming chamber 92 is directed downward, while bubbles in the ink are raised by buoyancy, and separation of the ink and bubbles can be realized in a short time.

  The shape of the cross section (YZ cross section) of the main flow path portion 79b and the communication portion 79c is a rectangle whose longitudinal direction is the direction along the Y axis (see FIG. 3). Here, the communication portion 79c (FIG. 4) is gradually narrowed from the main flow passage portion 79b toward the defoaming chamber 92, and the cross-sectional area S2 at the contact portion with the defoaming chamber 92 is the same as that of the main flow passage portion 79b. Is smaller than the cross-sectional area S1 at the contact portion. Therefore, the average cross-sectional area of the communication part 79c is smaller than the cross-sectional area S1 of the main flow path part 79b. The above-mentioned cross-sectional area S2 is preferably smaller than the cross-sectional area of the bubbles that have grown from the bubbles flowing from the upstream, and can be, for example, 0.5 square millimeters.

  In the example of FIG. 4, large bubbles BL are captured in the recess 20 (the ceiling portion of the defoaming chamber 92) of the partition plate 10 in the defoaming chamber 92. The bubbles BL are, for example, raised after a plurality of fine bubbles flow from the upstream in the ink filled in the defoaming chamber 92, and these bubbles that have reached the ceiling portion gather and grow. Here, the communication part 79c is formed as an upward flow path from the main flow path part 79b to the defoaming chamber 92 because the fine bubbles rising in the defoaming chamber 92 or the ceiling part like the bubbles BL are formed. This is to prevent the air bubbles trapped in the back flow from flowing back into the internal flow path 79. That is, even if there is a bubble that enters the communication portion 79c, the bubble that has entered the buoyancy lifts the communication portion 79c and returns to the defoaming chamber 92, and the bubble flows back to the main flow path portion 79b and its upstream side. Can be suppressed. The reason why the cross-sectional shape of the communication portion 79c is a rectangle whose longitudinal direction is the longitudinal direction is as follows. In general, the bubble BL is a circle or an ellipse whose shape is collapsed in the lateral direction. Therefore, by making the cross-sectional shape of the communication portion 79c a vertically long rectangle, the length in the horizontal direction (short direction) is made shorter than the diameter (or long axis) of the bubble BL, so that the bubble BL into the communication portion 79c. This is because the flowability of the ink can be improved by increasing the cross-sectional area of the communication portion 79c while suppressing the intrusion of the ink. Further, the average cross-sectional area of the communication portion 79c is smaller than the cross-sectional area S1 of the main flow path portion 79b because the bubble BL is connected to the communication portion by reducing the area of the connection portion with the communication portion 79c on the wall surface of the defoaming chamber 92. This is to prevent entry into 79c. The internal flow path 79 and the main flow path portion 79b correspond to the liquid supply path in the claims.

  FIG. 5 is a plan view showing a detailed configuration of the recess 23 in the second defoaming chamber plate 13 shown in FIG. In FIG. 5, the figure which looked at the recessed part 23 from upper direction is shown. The planar shape of the bottom surface BS of the recess 23 is not a rectangle but an R shape (curved shape) with rounded corners. In addition, the flow path 79 a is disposed at a position corresponding to the upper right end of the recess 23. Accordingly, when the ink flows from the flow path 79a into the defoaming chamber 92 at high speed, for example, at the initial filling of the ink, the flowing ink changes in the direction along the wall surface of the recess 23 after flowing in the −X direction. It will go down. In this case, as shown in FIG. 5, since the ink flows as a vortex into the ink discharge flow path 154, the bubbles remaining in the defoaming chamber 92 can be reduced. Further, the curvature radii of the four corners in the contour of the horizontal cross section (XZ cross section) of the concave portion 23 increase from the opening portion (the portion where the filter is disposed) to the bottom surface BS. Accordingly, it is possible to suppress the bubbles from stagnating on the side surface as it goes downward in the concave portion 23, and to collect the bubbles in the ceiling portion (partition wall portion 90).

  As described above, in the carriage 100, the internal flow path 79 is connected to the side wall of the defoaming chamber 92 via the flow path 79a. Therefore, the ink that has flowed into the defoaming chamber 92 flows downward from the side surface, and the bubbles in the ink can be directed upward by buoyancy, so that the ink and the bubbles can be easily separated. Therefore, bubbles in the ink can be collected in the ceiling portion (partition wall 90) of the defoaming chamber 92 in a short time, and a large amount of bubbles can be removed in a short time. In addition, since the communication portion 79c is formed as an upward flow passage from the main flow passage portion 79b to the defoaming chamber 92, the bubbles in the defoaming chamber 92 are transferred to the main flow passage portion 79b or its upstream side (internal flow passage 79). ) Can be prevented from flowing back. In addition, by configuring the communication portion 79c as an upward flow path in this way, the thickness (length in the Y-axis direction) of the ceiling portion of the main flow path portion 79b can be increased. Therefore, the evaporation of moisture from the main flow path portion 79b can be suppressed, and the increase in the viscosity of the ink can be suppressed. Further, since the cross section of the communication portion 79c is rectangular, and the average cross sectional area of the communication portion 79c is configured to be smaller than the cross sectional area S1 of the main flow path portion 79b, the bubbles BL in the defoaming chamber 92 are formed. Can be prevented from entering the communication portion 79c. Further, since the side surface of the defoaming chamber 92 has an R shape, it is possible to suppress the bubbles from staying on the side surface of the defoaming chamber 92. On the other hand, since the shape of the outline of the cross section (XZ cross section) of the ceiling part (partition wall part 90) of the defoaming chamber 92 is rectangular, the contact area between the partition part 90 and the bubbles can be increased, and the ceiling Bubbles can be stagnated at the four corners of the part. In addition, the defoaming chamber 92 is not configured to be filled with an ink absorbing material, and can store ink directly, thereby suppressing the stored ink from remaining in the defoaming chamber. Can do. In addition, since no ink absorbing material is used, the manufacturing cost of the carriage 100 can be reduced. In addition, since no ink absorbing material is used, as shown in FIG. 5, it is possible to improve the discharge of bubbles using the flow of ink that has flowed into the defoaming chamber 92.

B. Second embodiment:
FIG. 6 is an explanatory diagram showing the stacked state of the plates constituting the carriage in the second embodiment. 6 shows the same AA cross section as FIG. The carriage as the defoaming mechanism in the second embodiment is different from the carriage 100 (FIGS. 1 to 5) in the configuration of the communication portion, and the other configurations are the same as those in the first embodiment.

  Specifically, the communication portion 79 c (FIG. 4) in the first embodiment is gradually narrowed from the main flow path portion 79 b toward the defoaming chamber 92, and a cross-sectional area at a contact portion with the defoaming chamber 92. S2 was smaller than the cross-sectional area S1 (the cross-sectional area S1 of the main flow path portion 79b) at the contact portion with the main flow path portion 79b. In contrast, the communication portion 79d in the second embodiment has a constant cross-sectional area. The cross-sectional area of the communication portion 79d is the same as the cross-sectional area S1 of the main flow path portion 79b. Further, the communication portion 79d is formed as an upward flow path from the main flow path portion 79b to the defoaming chamber 92, similarly to the communication portion 79c of the first embodiment.

  The carriage in the second embodiment having such a configuration has the same effect as the carriage 100 in the first embodiment.

C. Third embodiment:
FIG. 7 is an explanatory diagram showing a stacked state of plates constituting the carriage in the third embodiment. 7 shows the same AA cross section as FIG. The carriage as the defoaming mechanism in the third embodiment is different from the carriage 100 (FIGS. 1 to 5) in the configuration of the communication portion, and the other configurations are the same as those in the first embodiment.

  Specifically, the communication portion 79c (FIG. 4) in the first embodiment is formed as an upward flow passage from the main flow passage portion 79b to the defoaming chamber 92, but the communication portion in the second embodiment. 79f is formed as a flow path extending in the horizontal direction from the main flow path portion 79b to the defoaming chamber 92. The communication portion 79f is gradually narrowed from the main flow path portion 79b toward the defoaming chamber 92, like the communication portion 79c of the first embodiment.

  The carriage in the third embodiment having such a configuration has the same effect as the carriage 100 in the first embodiment.

D. Fourth embodiment:
FIG. 8 is an explanatory view showing a stacked state of plates constituting the carriage in the fourth embodiment. 8 shows the same AA cross section as FIG. The carriage as the defoaming mechanism in the fourth embodiment is different from the carriage 100 (FIGS. 1 to 5) in the configuration of the communication portion, and the other configurations are the same as those in the first embodiment.

  Specifically, the communication portion 79g of the second embodiment is formed as a flow path extending in the horizontal direction having a partition portion D1 at the center. The partition part D1 divides the flow path into upper and lower parts. Both of these two flow paths have the same cross-sectional area S3, and the total cross-sectional area is the same as the cross-sectional area S2 at the contact portion between the communicating portion 79c and the defoaming chamber 92 in the first embodiment. is there.

  The carriage of the fourth embodiment having such a configuration has the same effect as the carriage 100 of the first embodiment. Further, since the communication portion 79g is provided with the partition portion D1 to divide the flow path, the cross-sectional area of the contact surface with the defoaming chamber 92 of each flow path is reduced to suppress the intrusion of bubbles, The total area of the contact surface with the defoaming chamber 92 as the internal flow path 79 can be increased to improve the ink flowability.

E. Fifth embodiment:
FIG. 9 is an explanatory diagram showing a stacked state of plates constituting the carriage in the fifth embodiment. 9 shows the same AA cross section as FIG. The carriage as the defoaming mechanism in the fifth embodiment has the carriage 100 in that the main flow path portion 79b is not provided and the connection position of the defoaming chamber 92 with the communicating portion is not a side wall but a ceiling portion. (FIGS. 1 to 5) The other configurations are the same as those in the first embodiment.

  Specifically, the partition plate 10a in the fifth embodiment does not include the flow path forming portion 52. Further, the partition wall portion 90a of the partition wall plate 10a is shorter in the horizontal direction than the partition wall portion 90 of the first embodiment, and includes a communication portion 79h adjacent to the partition wall portion 90a. The communication portion 79h is a through hole that penetrates the partition plate 10a in the thickness direction.

  In the decompression chamber plate 11a in the fifth embodiment, the through hole 53 is disposed adjacent to the upper portion of the communication portion 79h when the plates are stacked. Therefore, the communication part 79h described above connects the through hole 53 (internal flow path 79) and the defoaming chamber 92 in the vertical direction (direction parallel to the Y axis). The first defoaming chamber plate 12a in the fifth embodiment does not include the flow path forming portion 54. In this embodiment, the internal flow path 79 corresponds to the liquid supply path in the claims.

  Here, the cross section (XZ cross section) of the communication portion 79h is rectangular, and the area thereof is the same as the cross sectional area S2 at the contact portion between the communication portion 79c and the defoaming chamber 92 in the first embodiment (for example, 0.5 square millimeters). Further, the area of the communication portion 79h is smaller than the cross-sectional area S3 of the through hole 53 (internal flow path 79).

  In the carriage of the fifth embodiment having such a configuration, the communication portion 79h has a small cross-sectional area, and the large bubble BL that has grown is difficult to pass through. Therefore, it is possible to prevent bubbles in the ink from entering the internal flow path 79 and flowing back, and a large amount of bubbles can be removed within a short time. In addition, since the cross-sectional shape of the communication portion 79h is rectangular, the cross-section of the communication portion 79h can be made shorter than the diameter of the bubble BL in at least the short direction, and the bubble BL can be prevented from entering the communication portion 79c. .

F. Sixth embodiment:
FIG. 10 is an explanatory view showing the stacked state of the plates constituting the carriage in the sixth embodiment. 10 shows the same AA cross section as FIG. The carriage as the defoaming mechanism in the sixth embodiment is different from the carriage 100 (FIGS. 1 to 5) in that the connection position with the communicating portion in the defoaming chamber 92 is not the side wall but the bottom surface BS. This is the same as the first embodiment.

  Specifically, the partition plate 10b in the sixth embodiment does not include the flow path forming portion 52. The first defoaming chamber plate 12b in the sixth embodiment does not include the flow path forming portion 54. The first defoaming chamber plate 12b includes a through hole 49 penetrating in the thickness direction. And when each plate is laminated | stacked, the through-holes 53, 51, and 49 are mutually connected, and comprise a part of internal flow path 79. FIG.

  The second defoaming chamber plate 13a in the sixth embodiment is provided with a flow path 79m. This flow path 79m constitutes a part of the internal flow path 79, like the flow path 79a in the first embodiment. The flow path 79m includes a main flow path part 79j and a communication part 79k. The main flow path portion 79j is a flow path bent in an L shape, and one end reaches the upper surface of the second defoaming chamber plate 13a. And when each plate is laminated | stacked, the main flow path part 79j is connected with the internal flow path 79 (through-hole 49).

  The communication part 79k communicates the defoaming chamber 92 and the main flow path part 79j. One end of the communication portion 79k is connected to the main flow path portion 79j, and the other end is connected to the bottom surface BS of the defoaming chamber 92. The communication portion 79k is formed as an upward flow path from the main flow path portion 79j toward the defoaming chamber 92 (bottom surface BS), similarly to the communication portion 79c in the first embodiment. Further, the communication portion 79k is gradually narrowed from the main flow passage portion 79j toward the defoaming chamber 92, and the cross-sectional area S2 at the contact portion with the defoaming chamber 92 is at the contact portion with the main flow passage portion 79j. It is smaller than the cross-sectional area S1. Therefore, the average cross-sectional area of the communication portion 79k is smaller than the cross-sectional area S1 of the main flow path portion 79j. The above-described cross-sectional area S2 can be set to, for example, 0.5 square millimeters as in the first embodiment.

  The carriage in the sixth embodiment having such a configuration has the same effect as the carriage 100 of the first embodiment.

G. Variation:
In addition, elements other than the elements claimed in the independent claims among the constituent elements in each of the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

G1. Modification 1:
In each of the above-described embodiments, the cross-sectional shape of the communication portions 79c, 79d, 79f, and 79g is a rectangle whose longitudinal direction is the longitudinal direction, but may be a rectangle whose longitudinal direction is the lateral direction instead. it can. Moreover, the cross-sectional shape can be made into arbitrary shapes with a longitudinal direction and a transversal direction, such as a triangle and a pentagon, instead of a rectangle. By doing in this way, penetration of the bubble BL from the defoaming chamber 92 into the communicating portion can be suppressed. Note that the above-described cross-sectional shape may be any shape such as a square or a circle that does not have a longitudinal direction and a short direction.

G2. Modification 2:
In each of the above-described embodiments, the bottom of the defoaming chamber 92 has an R shape. However, instead of this, a shape having an acute angle portion (for example, a quadrangular prism shape) may be used. It is also possible to fill a defoaming chamber with a member that absorbs ink, and the ink absorbing member can suck and store the ink.

G3. Modification 3:
In each of the above-described embodiments, the gas permeable portion between the decompression chamber 80 and the defoaming chamber 92 is integrally formed as the partition walls 90 and 90a. And the ceiling surface of the defoaming chamber 92 may be formed as separate walls having gas permeability, and these walls may be in contact with each other when a plurality of plates are stacked. Further, the boundary position of each plate is not limited to the position shown in each embodiment, and may be an arbitrary position. Further, the number of plates constituting the carriage can be set to an arbitrary number. For example, in each embodiment, the total number of plates forming the defoaming chamber 92 is three. However, instead of this, four plates may be used.

G4. Modification 4:
In the first embodiment described above, the connection position with the communicating portion on the side wall (side surface) of the defoaming chamber 92 was above half the height of the side surface of the defoaming chamber 92, but instead of this, The position of the side of the defoaming chamber 92 may be half or less of the height. Moreover, in each Example, the connection position (connection surface) with the communicating part in the defoaming chamber 92 was any one of the side wall (side surface), the upper surface, and the bottom surface. It can also be a corner. Moreover, it can also be set as the structure connected to a communication part in several surfaces of the defoaming chamber 92, such as providing a communication part in a side surface and an upper surface, respectively. In this case, the communication portions 79c, 79d, 79f, 79g, 79h, and 79k of the above-described embodiments can be used in combination.

G5. Modification 5:
In each of the above-described embodiments, the type of ink ejected by the printer 500 is four colors. However, instead of this, any type of ink can be ejected. The printer of each embodiment is an off-carriage type printer, but instead of this, a so-called on-carriage type printer in which an ink cartridge is mounted on a carriage can be adopted.

G6. Modification 6:
In the first embodiment described above, the communication part 79c is an upward flow path that monotonously rises from the main flow path section 79b toward the defoaming chamber 92, but instead of this, the upward flow path that rises stepwise It can also be a flow path. In addition, the communication portion 79c can be a flow passage that is bent concavely or convexly toward the defoaming chamber 92 from the main flow passage portion 79b. That is, generally, as the communication portion 79c, a flow of any shape in which the position where the communication portion 79c is connected to the defoaming chamber 92 (the side wall thereof) is higher than the position where the communication portion 79c is connected to the main flow path portion 79b. The path can be employed in the defoaming mechanism of the present invention.

G7. Modification 7:
In each of the embodiments described above, an example is shown in which the defoaming mechanism in the printer 500 is applied to a carriage, but instead, a defoaming mechanism can be configured separately from the carriage. For example, in each Example, a defoaming mechanism can also be comprised by providing a defoaming chamber and a decompression chamber in the middle of tubes t11-t14. Even in such a configuration, a large amount of bubbles can be removed in a short time by configuring the communicating portion that communicates the tubes t11 to t14 and the defoaming chamber as in the above-described embodiments.

G8. Modification 8:
In each of the above-described embodiments, the ink jet printer has been described. However, the present invention is not limited to this, and can be applied to any liquid ejecting apparatus that ejects liquid other than ink. For example, image recording devices such as facsimile machines, color material ejection heads used in the manufacture of color filters such as liquid crystal displays, electrodes such as organic EL (Electro Luminescence) displays and surface emission displays (Field Emission Display, FED) Electrode material injection device used for forming, liquid injection device for injecting liquid containing bio-organic matter used for biochip manufacturing, sample injection device as a precision pipette, lubricating oil injection device, resin liquid injection device Etc. In addition, transparent resin liquids such as UV curable resins to form liquid injection devices that inject lubricating oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid ejecting apparatus that ejects a liquid onto the substrate, or a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate or the like may be employed. The present invention can be applied to any one of the 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 ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be any material that can be ejected by the liquid ejecting apparatus. For example, it may be in the state when the substance is in a liquid phase, and may be in a liquid state 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 the substance, as well as particles in which functional material particles made of solid materials such as pigments and metal particles are dissolved, dispersed or mixed in a solvent. In addition, typical examples of the liquid include ink and liquid crystal as described in the above embodiments. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot-melt inks.

It is explanatory drawing which shows schematic structure of the printer 500 provided with the carriage 100 as a defoaming mechanism of this invention. FIG. 6 is an explanatory diagram illustrating states of the carriage 100 and the recording head 150 during ink ejection, and an explanatory diagram illustrating states of the carriage 100 and the recording head 150 after ink has flowed into the first pressure chamber 77 from the opened ink inlet 76. is there. 2 is a perspective view illustrating a detailed configuration of a carriage 100. FIG. It is sectional drawing which shows the detail of the AA cross section shown in FIG. It is a top view which shows the detailed structure of the recessed part 23 in the 2nd defoaming chamber plate 13 shown in FIG. It is explanatory drawing which shows the lamination | stacking state of the plate which comprises the carriage in a 2nd Example. It is explanatory drawing which shows the lamination | stacking state of the plate which comprises the carriage in a 3rd Example. It is explanatory drawing which shows the lamination | stacking state of the plate which comprises the carriage in a 4th Example. It is explanatory drawing which shows the lamination | stacking state of the plate which comprises the carriage in a 5th Example. It is explanatory drawing which shows the lamination | stacking state of the plate which comprises the carriage in a 6th Example.

Explanation of symbols

    IC1 to IC4 ... ink cartridges, 10, 10a, 10b ... partition plate, 11, 11a ... decompression chamber plate, 12, 12a, 12b ... first defoaming chamber plate, 13, 13a ... second defoaming chamber plate, 14 ... Tube, 20, 21, 23 ... recess, 22, 49, 51, 53 ... through hole, 52, 54, 66 ... flow path forming part, 60 ... filter chamber, 61 ... filter, 62, 64 ... internal flow path, 65 ... Flow hole, 70 ... Valve chamber, 71 ... First pressure regulating valve, 72 ... Valve element, 73 ... Pressure adjusting spring, 74 ... Support rod, 75 ... Seal member, 76 ... Ink inlet, 77 ... First pressure chamber 79 ... internal flow path, 79a, 79m ... flow path, 79b, 79j ... main flow path section, 79c, 79d, 79f, 79g, 79k ... communication section, 80 ... decompression chamber, 81 ... second pressure regulating valve, 82 ... Valve body, 83 ... Pressure control Spring, 84 ... support rod, 85 ... sealing member, 86 ... communication hole, 87 ... atmospheric chamber, 88a, 88b ... partition wall, 89 ... second pressure chamber, 90, 90a ... partition wall, 92 ... defoaming chamber, 93 DESCRIPTION OF SYMBOLS ... Filter, 95 ... Ink discharge flow path, 99 ... Atmospheric communication hole, 100 ... Carriage, 150 ... Recording head, 152 ... Nozzle plate, 154 ... Ink discharge flow path, 220a-220d ... Ink supply pump, 260 ... Guide rod 270 ... Platen, 300 ... Pressure reducing pump, 358 ... Negative pressure supply path, 500 ... Printer, P ... Recording paper, t1 to t5, t11 to t14 ... Tube, BL ... Bubble, BS ... Bottom

Claims (6)

A defoaming mechanism for removing bubbles from a liquid flowing in the liquid ejecting apparatus,
A defoaming chamber having a top surface, a bottom surface, and a side surface extending in a vertical direction, for trapping bubbles in the liquid;
A backflow suppression unit that connects the defoaming chamber and the liquid supply path in the liquid ejecting apparatus to suppress the backflow of the bubbles from the defoaming chamber to the liquid supply path;
A defoaming mechanism. The defoaming mechanism according to claim 1,
The backflow suppressing unit is a defoaming mechanism having a flow path having a cross-sectional area smaller than a cross-sectional area of the liquid supply path. In the defoaming mechanism according to claim 1 or 2,
The backflow suppression unit is a defoaming mechanism having a cross-sectional flow path having a longitudinal direction and a short direction. In the defoaming mechanism according to any one of claims 1 to 3,
The communication part is a defoaming chamber connected to the defoaming chamber at any one of the upper surface, the bottom surface, and the side surface. In the defoaming mechanism according to claim 4,
The communicating part is a defoaming chamber connected to the defoaming chamber above the half of the height of the side surface among the side surfaces.   A liquid ejecting apparatus comprising the defoaming mechanism according to any one of claims 1 to 5.

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