JP4590999B2 - Liquid ejecting apparatus and valve mechanism - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus and a valve mechanism.

  As a liquid ejecting apparatus that ejects liquid from a liquid ejecting head to a target, for example, an ink jet recording apparatus (hereinafter simply referred to as a printer) is known. This printer includes a cartridge that stores ink, and a supply channel that supplies ink from the cartridge to the recording head. A maintenance mechanism is usually provided in a non-printing area in the printer. This maintenance mechanism includes a suction pump and the like, and performs cleaning for sucking ink, bubbles, and the like thickened from the nozzles in order to prevent nozzle clogging and the like of the recording head.

  Some printers include a valve mechanism for performing choke cleaning in the middle of a supply flow path provided between a cartridge and a recording head (see, for example, Patent Document 1). In choke cleaning, the valve mechanism provided in the supply flow path is closed and the suction pump of the maintenance mechanism is driven to depressurize the supply flow path downstream of the valve mechanism. Then, after the suction pump is driven for a predetermined time, the valve mechanism is opened, ink is vigorously flowed into the supply flow path where the pressure has decreased, and the thickened ink and bubbles in the supply flow path and the recording head are recorded. Eject from the head nozzle.

As this valve mechanism, an electromagnetic control valve as described in Patent Document 1 can be used, but a valve mechanism that opens and closes by fluid pressure as shown in FIGS. 14 and 15 has also been proposed. The valve mechanism 100 includes a pressure chamber 102 in which ink introduced from the introduction port 101 is temporarily stored, and a part of the wall surface of the pressure chamber 102 is configured by a flexible film 103. Further, in the pressure chamber 102, a protrusion 105 having an ejection port 104 opened on the surface facing the film 103 is formed, and the ink in the pressure chamber 102 is reduced as shown in FIG. When bent, the film 103 comes into contact with the valve seat to block the discharge port 104. At the time of choke cleaning, the ink in the pressure chamber 102 is discharged by driving the suction pump to reduce the ink in the pressure chamber 102, and the film 103 is brought into contact with the protrusion 105. Then, by continuing to drive the suction pump, negative pressure is accumulated in the flow path downstream from the discharge port 104, and then the ink is pumped from the upstream side of the valve mechanism 100, and the film 103 is shown in FIG. As described above, the protrusion 105 is separated. As a result, the ink flows all at once from the opened discharge port 104 into the flow path in which the negative pressure is accumulated, and bubbles, thickened ink, and the like are discharged from the recording head together with the ink having an increased flow velocity. That is, this valve mechanism 100 has the advantage that it does not require electrical control and is structurally simpler than the solenoid valve.
JP 2001-38925 A

However, in the case where minute bubbles A are mixed in the ink in the pressure chamber 102 and the bubbles A stay in the peripheral portion of the pressure chamber 102 as shown in FIG. 14, the bubbles A are discharged while they are minute. It was difficult. In particular, when the valve mechanism 100 is arranged so that the film 103 is vertical, the bubbles A gather in the vertical direction above the pressure chamber 102, and it is difficult to move the bubbles A downward in the vertical direction. If the bubble A in the pressure chamber 102 is not discharged, even if it is a minute bubble at first, a plurality of bubbles A gather to form a large bubble. When the volume of the bubbles is increased, the bubbles are relatively easily discharged from the discharge port 104. When the bubbles are supplied to the recording head together with the ink during printing, dot missing or the like occurs, and printing cannot be performed satisfactorily.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid ejecting apparatus and a valve mechanism capable of performing choke cleaning with simple control without increasing the size of the apparatus and improving bubble discharge performance. Is to provide.

The liquid ejecting apparatus of the present invention includes a liquid storing unit that stores a liquid, a liquid ejecting head that ejects liquid from a nozzle, a liquid supply path that communicates the liquid storing unit and the liquid ejecting head, and the liquid ejecting head. In the liquid ejecting apparatus including the suction means for sucking the liquid from the nozzle, a pressure chamber having a liquid introduction portion and a discharge portion is provided in the middle of the liquid supply path, and the pressure chamber is provided on one of its wall surfaces. parts comprises a said flexible member as Rutotomoni formed of a flexible member which is displaced with the pressure difference between the inside and the outside, facing the wall of the pressure chamber which faces said flexible member, spaced from the discharge portion The flexible member is formed so as to be relative to the opposing wall surface of the flexible member when the suction means sucks the liquid from the pressure chamber through the discharge portion. distance The suction means is in contact with the discharge portion so as to gradually close contact with the opposing wall surface from a small portion and closes the discharge portion, and in contact with the discharge portion. However, the negative pressure is accumulated in the flow path closer to the liquid jet head than the discharge section in the liquid supply path, and is separated from the discharge section when the liquid is pumped into the pressure chamber through the introduction section.

  According to this configuration, the liquid ejecting apparatus includes the liquid storage unit, the liquid ejecting head, the liquid supply path, and the suction unit that sucks the liquid from the nozzle of the liquid ejecting head. The liquid ejecting apparatus includes a pressure chamber provided with a liquid introduction portion and a discharge portion in the middle of the liquid supply path, and a part of the wall surface of the pressure chamber is a flexible member that is displaced in accordance with a pressure difference between the inside and the outside. Is formed. For this reason, by sucking the liquid from the nozzle of the liquid jet head by the suction means, the liquid supply path and the pressure chamber can be depressurized, the flexible member can be displaced to the inside of the pressure chamber, and the discharge portion can be closed. . Then, after accumulating negative pressure in the liquid supply path on the downstream side from the pressure chamber, the flexible member can be displaced in a direction away from the discharge portion by pumping the liquid into the pressure chamber. Accordingly, it is possible to perform so-called choke cleaning in which the liquid in the pressure chamber flows into the liquid supply path in which the negative pressure is accumulated, and the bubbles and impurities in the flow path are discharged together with the liquid having an increased flow rate. For this reason, without using an electromagnetic control valve or the like, the apparatus can be prevented from being enlarged, and the choke cleaning can be easily performed.

  In addition, the pressure chamber is formed so that the relative distance from the flexible member becomes smaller as the wall surface facing the flexible member is separated from the discharge portion. For this reason, when the flexible member is displaced inward as the liquid decreases, the flexible member can be brought close to the wall surface spaced from the discharge portion. Therefore, the bubbles staying in the corner away from the discharge unit are pushed out together with the liquid to the discharge unit side by reducing the distance between the flexible member and the wall surface. For this reason, when the liquid is pumped into the pressure chamber, the bubbles collected around the discharge portion can be easily discharged from the discharge portion together with the liquid having an increased flow velocity.

In the liquid ejecting apparatus, the pressure chamber is formed such that a region on the upper side in the vertical direction of the facing wall facing the flexible member has a small relative distance to the flexible member.
According to this, the pressure chamber is formed such that the region on the upper side in the vertical direction of the opposite wall surface facing the flexible member has a small relative distance to the flexible member. For this reason, when the bubbles tend to concentrate and stay in the vertical direction above the pressure chamber, the bubble discharge property of the pressure chamber can be particularly improved.

In this liquid ejecting apparatus, the opposing wall surface facing the flexible member is formed as an inclined surface whose relative distance from the flexible member continuously decreases as the distance from the discharge portion increases.
According to this, the opposing wall surface facing the flexible member is an inclined surface in which the relative distance from the flexible member continuously decreases as the distance from the discharge portion increases. For this reason, when the liquid in the pressure chamber is reduced and the flexible member is displaced inward, the adhesiveness between the flexible member and the opposing wall surface is enhanced, and it is possible to easily send out the bubbles to the discharge portion side. .

In the liquid ejecting apparatus, the discharge unit includes a protrusion formed on an opposing wall surface facing the flexible member, and a discharge hole opened on an upper surface of the protrusion.
According to this, the discharge part is provided with the protrusion formed in the opposing wall surface, and the discharge hole opened on the upper surface of the protrusion. It opens in the upper surface of the protrusion formed in the bottom face of the pressure chamber. For this reason, a discharge part can be easily opened and closed by the displacement of a flexible member.

In the liquid ejecting apparatus, the introduction portion that introduces liquid from the liquid supply path into the pressure chamber is formed below the pressure chamber in the vertical direction.
According to this, the introduction part is formed vertically below the pressure chamber. For this reason, since the bubbles staying in the upper part in the vertical direction of the pressure chamber are unlikely to flow backward to the introduction portion, it is possible to prevent the bubbles from flowing backward to the liquid storage means.

The valve mechanism of the present invention comprises a pressure chamber having an inlet portion and a discharge portion of the liquid, the discharge with flexible member forming a part of the wall of the pre-Symbol pressure chamber to the pressure difference between the inside and outside of the pressure chamber A valve mechanism that switches a communication state between the introduction part and the discharge part by being displaced so as to come into contact with and away from the part, wherein an opposing wall surface of the pressure chamber facing the flexible member is The flexible member is formed so that a relative distance from the flexible member decreases as the distance from the discharge unit increases, and the flexible member is flexible when the liquid is sucked from the pressure chamber through the discharge unit. The contact member is displaced so as to gradually come into close contact with the opposite wall surface from a portion having a small relative distance to the opposite wall surface in the adhesive member, and contacts the discharge portion so as to close the discharge portion. In front of the Than the discharge portion of the liquid supply path away from the discharge portion when the liquid is pumped into the pressure chamber through the inlet portion with negative pressure is accumulated in the flow path of the liquid ejecting head side.

  According to this, the valve mechanism includes a pressure chamber having an introduction part and a discharge part. The pressure chamber is formed so that the relative distance from the flexible member becomes smaller as the wall surface facing the flexible member is separated from the discharge portion. For this reason, when the flexible member is displaced inward as the liquid decreases, the flexible member can be brought close to the wall surface spaced from the discharge portion. Therefore, the bubbles staying in the corner away from the discharge unit are pushed out together with the liquid to the discharge unit side by reducing the distance between the flexible member and the wall surface. For this reason, when the liquid is pumped into the pressure chamber, the bubbles collected around the discharge portion can be easily discharged from the discharge portion together with the liquid having an increased flow velocity.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a main part of an ink jet printer (hereinafter simply referred to as a printer) as a liquid ejecting apparatus, and FIGS. 2 to 4 are schematic views illustrating the main part of the printer.

  As shown in FIG. 1, the printer 1 includes a guide member 2 installed in a frame (not shown), and a carriage 3 is slidably supported on the guide member 2. A carriage motor is drivingly connected to the carriage 3 via a timing belt (both not shown). The carriage 3 is equipped with six sub tanks 4 that contain various inks as liquids. Further, a recording head 5 as a liquid ejecting head is mounted on the lower surface of the carriage 3. The recording head 5 includes six nozzle rows including a plurality of nozzles N (see FIG. 4), and each nozzle N communicates with each sub tank 4. When a piezoelectric element (not shown) provided in the recording head 5 is driven, the ink supplied into the recording head 5 is ejected as an ink droplet from the nozzle N toward a paper (not shown) below the recording head 5. Then, by driving the carriage motor, the recording head 5 mounted on the carriage 3 reciprocates in the main scanning direction to eject ink droplets, and a paper feeding mechanism (not shown) sub-scans the paper below the recording head 5. Printing is performed by alternately repeating the operation of conveying in the direction.

  Further, the printer 1 is provided with a box-shaped first holder 6 provided on the right side in FIG. Three storage chambers CS (see FIGS. 2 and 6) are defined in the first holder 6, and each storage chamber CS has a cartridge C as a liquid storage unit that stores various inks as shown in FIG. Are detachably disposed. The second holder 7 provided on the left side in FIG. 1 has the same configuration as the first holder 6 and fixes the three cartridges C so as to be detachable.

  As shown in FIG. 2, each ink is formed on the front inner surface of each storage chamber CS formed in the first and second holders 6 and 7 toward the openings of the first and second holders 6 and 7. Each of the needles N1 is formed to protrude. Further, an ink outlet path 8 opened at the tip of the ink needle N1 is formed through the ink needle N1, and the ink outlet path 8 is passed through the front wall portions of the first and second holders 6 and 7. Further, an air introduction portion 15 is formed to project from the inner side surface of each storage chamber CS. An air flow path 16 is formed through the air introduction part 15.

  As shown in FIGS. 1 and 2, first and second supply members 11 and 12 as outer members are connected and fixed to the front surfaces of the first and second holders 6 and 7, respectively. As shown in FIG. 2, the first and second supply members 11, 12 are formed with communication holes 13 penetrating in the thickness direction. The communication hole 13 is connected to the ink outlet path 8 communicating with the ink needle N1 when the first and second supply members 11 and 12 are connected to the first and second holders 6 and 7, respectively.

  Further, through holes 17 are formed through the first and second supply members 11 and 12, respectively. The through hole 17 communicates with the air flow path 16 of the air introduction portion 15 when the first and second supply members 11 and 12 are connected to the first and second holders 6 and 7. An air supply tube 18 having one end connected to the pressurizing pump P1 is inserted into the insertion hole 17. The illustration of the through holes 17 and the air supply tubes 18 of the first and second supply members 11 and 12 shown in FIG.

  As shown in FIG. 2, the cartridge C includes an ink pack 21 in a case 20 formed in a casing shape. First and second insertion holes 20 a and 20 b are formed through the front wall portion of the case 20. The ink pack 21 includes a bag portion 21a formed of a flexible material film, and the bag portion 21a is filled with ink. Further, the bag portion 21a is provided with a lead-out portion 21b for leading the ink in the bag portion 21a to the outside so as to protrude from the bag portion 21a. A through hole 21c is formed. When the lead-out portion 21 b is inserted into the first insertion opening 20 a formed in the case 20, the ink pack 21 is fixed in the case 20.

  As shown in FIG. 3, when each cartridge C containing the ink pack 21 is attached to the first and second holders 6 and 7, the ink needle N <b> 1 is formed in the first insertion formed in the case 20 of the cartridge C. Through the opening 20a, the ink pack 21 is inserted into an insertion hole 21c provided in the lead-out portion 21b. Thereby, the ink in the bag part 21a flows into the ink needle N1. Moreover, the air introduction part 15 provided in each accommodation chamber CS is inserted in the 2nd penetration opening 20b of case 20. As shown in FIG. In this state, when the pressure pump P1 is driven, air is pumped into the case 20 of each cartridge C via the air supply tube 18 and the air flow path 16, and into the space between the case 20 and the ink pack 21. Filled. When the inside of the case 20 becomes a high pressure state, the ink pack 21 is crushed by the air pressure, and the ink is pushed out from the bag portion 21a to the outlet portion 21b side. The pushed ink is introduced into the communication hole 13 formed in the first and second supply members 11 and 12 through the ink outlet path 8 of the ink needle N1. The ink introduced into the communication hole 13 is introduced into an ink flow path extending from the base end side of the first and second supply members 11 and 12 formed continuously to the communication hole 13 toward the front end side.

  As shown in FIG. 1, an ink supply tube 22 is connected to the tips of the first and second supply members 11 and 12. The ink supply tube 22 includes six pipe lines (not shown) inside, and each pipe line is connected to each ink flow path formed in the first and second supply members 11 and 12. The other end of the ink supply tube 22 is connected to the carriage 3 so that ink can be supplied to each sub tank 4. Therefore, the ink pumped from the ink pack 21 to the respective ink flow paths of the first and second supply members 11 and 12 by driving the pressure pump P1 is supplied to each sub tank 4 via the ink supply tube 22. The

  As shown in FIG. 1, the printer 1 includes a maintenance mechanism 25 that is within the moving range of the carriage 3 and outside the paper conveyance area. As shown in FIG. 4, the maintenance mechanism 25 includes a cap 26. The cap 26 is formed in a box shape with an upper surface open, and is separated from the lower surface of the recording head 5 by a working position (see FIG. 4) that contacts the lower surface of the recording head 5 at the home position by a cap lifting mechanism (not shown). Reciprocate between the retracted position. In the printing pause state, the nozzle moves to the operating position to prevent the vicinity of each nozzle N opening of the recording head 5 from being dried and to prevent the nozzle N from being clogged.

  As shown in FIG. 4, a suction port 26a is formed through the bottom wall of the cap 26, and a discharge tube 27 is connected to the suction port 26a. Further, in the middle of the discharge tube 27, a suction pump P2 as a suction means is provided. For this reason, when the suction pump P2 is driven in a state where the recording head 5 is sealed by the cap 26, the sealed cap inner space S1 is depressurized, and ink and bubbles in the recording head 5, ink adhering to the lower surface, etc. It is discharged into the cap internal space S1. The ink discharged into the cap 26 is sent to the waste liquid tank T provided in the vicinity of the maintenance mechanism 25 via the discharge tube 27 and is absorbed by the absorbent material Ta accommodated in the waste liquid tank T.

  Next, the first and second supply members 11 and 12 will be described in detail with reference to FIGS. The first and second supply members 11 and 12 differ only in that the connecting portion with the ink supply tube 22, the outer shape and the ink flow path are symmetrical, and the other configurations are the same. Only the 1 supply member 11 will be described. FIG. 5 is a front view of the first supply member 11, and FIG. 6 is a rear view of the first supply member 11. 7, 9 and 11 are cross-sectional views of the main part of the first supply member 11, and FIGS. 8 and 10 are front views of the main part of the first supply member 11.

  The 1st supply member 11 is formed from a synthetic resin, and is provided with the plate-shaped connection part 11a connected with the 1st holder 6 as shown in FIG. The connecting portion 11a is formed in a square shape, and as described above, the three insertion holes 17 through which the air supply tube 18 is inserted are arranged in a row in the horizontal direction so as to penetrate therethrough. . Further, as described above, the communication holes 13 communicating with the ink needles N <b> 1 of the first holder 6 are formed through the upper sides of the respective insertion holes 17. In addition, three groove-shaped first flow paths 31 provided continuously to the communication holes 13 are formed in the connecting portion 11a. Each of these 1st flow paths 31 is formed so that it may extend toward the connection part 11b formed continuously from the connection part 11a.

  The connection part 11b comprises a part of the 1st supply member 11 similarly to the connection part 11a, and is extended and formed so that it may bend to the left side from the upper part of the connection part 11a. In addition, the connection part 11b of the 2nd supply member 12 is formed so that it may bend on the right side from the connection part 11a, and if the 1st and 2nd supply members 11 and 12 are arranged in a straight line like FIG. The tip of the part 11b faces the center.

  Further, on the back surface 11d of the first supply member 11, as shown in FIG. 6, three second flow paths 32 communicating with the end of the first flow path 31 and the holes 32a are formed in a groove shape. ing. Each second flow path 32 has an inlet 32b that opens at the bottom surface of each circular recess 33 provided in the front surface 11c of the first supply member 11 and discharges ink into the circular recess 33 at the terminal side. .

  As shown in FIG. 5, the three circular recesses 33 are provided in a row in the connection portion 11 b. As shown in FIG. 7, the bottom surface 33 a of the circular recess 33 is an inclined surface that continuously deepens from the front surface 11 c of the first supply member 11. That is, the bottom surface 33a has a shallow peripheral edge and is deeper toward the center.

  As shown in FIG. 7, a projecting portion 34 constituting a discharge portion is formed at the center portion of the bottom surface 33 a of the circular recess 33. The protrusion 34 is formed in a substantially trapezoidal cross section, and has an upper surface that is the same height as the front surface 11c or a height that protrudes slightly outside the front surface 11c. In the center of the protrusion 34, a discharge hole 35 constituting a discharge portion is formed through. The discharge hole 35 includes an inlet 36 formed in a tapered shape in the protrusion 34 and a communication hole 37 communicating with the inlet 36. The communication hole 37 communicates with a groove-shaped third flow path 39 formed on the back surface 11 d of the first supply member 11. As shown in FIG. 6, the third flow path 39 extends toward the tip of the connection portion 11 b and communicates with the connection port 11 e with the ink supply tube 22.

  The first flow path 31 and the circular recess 33 formed on the front surface 11c of the first supply member 11 are sealed by fixing a film F1 (see FIG. 7) as a flexible member to the front surface 11c. . The film F1 is made of a thermoplastic resin that can be thermally welded to the first supply member 11, and is thermally welded to the first supply member 11 in a state where a portion that closes the circular recess 33 is bent toward the bottom surface 33a. . At this time, since the bottom surface 33a of the circular recess 33 is an inclined surface, the relative distance between the bottom surface 33a and the film F1 facing the bottom surface 33a is small at the periphery of the bottom surface 33a and large at the center of the bottom surface 33a. It has become.

  The second flow path 32 and the third flow path 39 formed on the back surface 11d of the first supply member 11 are formed by thermally welding a film F2 (see FIG. 7) made of a thermoplastic resin to the back surface 11d. Sealed. As a result, a flow path starting from the communication hole 13 and ending with the connection port 11e is formed, and this flow path, the ink supply tube 22, and the flow path to the nozzle N of the recording head 5 serve as a liquid supply path. Ink flow paths are formed.

  As shown in FIG. 7, when each circular recess 33 is sealed by the film F1, a pressure chamber 38 in which ink is temporarily stored is formed by the inner surface of the circular recess 33 and the film F1. Ink enters the pressure chamber 38 from the second flow path 32 and is temporarily stored, and ink is discharged from the discharge holes 35 formed in the protrusion 34 and flows into the third flow path 39.

  A portion of the film F1 thermally welded to the first supply member 11 that closes the circular concave portion 33 is a region (hereinafter referred to as a flexible portion K) that can be displaced with a pressure difference between the inside and the outside. ing. Specifically, when the ink in the pressure chamber 38 is discharged from the discharge hole 35 and the ink in the pressure chamber 38 is reduced, the flexible portion K comes into contact with the upper surface of the protrusion 34 as shown in FIG. The hole 35 is closed and the valve is closed.

  When ink flows into the pressure chamber 38 in the valve-closed state, the pressure that the flexible portion K receives from the ink in the pressure chamber 38 gradually increases. When the ink further flows into the pressure chamber 38, the flexible portion K is separated from the projection 34 as shown in FIG. 7, and the second flow path 32 and the discharge hole 35 are communicated with each other to open the valve. That is, the film F1 is required to be formed of a soft and lightweight material that is displaced as the ink in the pressure chamber 38 increases or decreases. The circular recess 33, the film F1, and the protrusion 34 constitute a choke valve B as a valve mechanism. The choke valve B is provided in the first supply member 11 so that the flexible portion K is along the vertical direction. The second supply member 12 is also provided with three choke valves B corresponding to the ink flow paths.

Next, the operation of the choke valve B will be described. When ink is supplied from the cartridge C to the recording head 5 for printing, the pressure pump P1 is driven, and the case 20 of the cartridge C is filled with air through the air supply tube 18. When the ink pack 21 is crushed by the air pressure, the ink is pushed out to the communication hole 13 through the ink needle N1. Further, the ink is pumped to the ink supply tube 22 via the first flow path 31, the second flow path 32, the choke valve B, and the third flow path 39, and is supplied to the recording head 5 via the ink supply tube 22. The That is, the pressure pump P1 resists the ink in the cartridge C against gravity,
A pressure that can be sent to the pressure chamber 38, the third flow path 39, and the like above the cartridge C in the vertical direction and further sent to the recording head 5 is generated in the cartridge C. Further, since the ink is temporarily stored in the pressure chamber 38 of the choke valve B, the open state where the flexible portion K does not contact the protrusion 34 is maintained. Even when the driving of the pressurizing pump P1 is stopped, the case 20 of the cartridge C is filled with air so as to have a pressure that crushes the ink pack 21, so that it is the starting end of the ink supply path. The communication hole 13 is applied with a pressure that does not allow ink to flow back from the choke valve B side.

  When the printer 1 starts printing from a long-term printing suspension state, or when a switch provided on a case (not shown) is pressed and a cleaning execution command is output, the carriage 3 moves to the home position, and the cap 26 Moves to the operating position. Further, the suction pump P2 is driven in a state where the recording head 5 is sealed with the cap 26, and the cap internal space S1 is decompressed. As a result, ink is discharged from the nozzles N of the recording head 5 and discharged into the cap inner space S1.

  At this time, when air bubbles enter the ink flow path due to air entering the ink flow path, local pressure drop, etc., as shown in FIG. Between the bottom surface 33a of 33 and the flexible portion K, minute bubbles A stay. At this time, since the introduction port 32b is provided below the pressure chamber 38 in the vertical direction, the bubble A does not flow backward to the cartridge C side. In the drawing, the bubble A is shown large for convenience.

  When the suction pump P2 is further driven, the ink in the third flow path 39, the discharge hole 35, and the pressure chamber 38 provided upstream from the nozzle N is also sucked downstream. When the choke valve B is in the open state, the ink in the pressure chamber 38 is ejected through the ejection hole 35, and the flexible portion K becomes the upper surface of the protrusion 34 as the ink in the pressure chamber 38 decreases. Displaced to approach At this time, as shown in FIG. 9, the flexible portion K comes into close contact with the bottom surface 33 a of the circular recess 33 from the peripheral portion having a small relative distance to the bottom surface 33 a. For this reason, the bubbles A staying between the flexible portion K and the bottom surface 33a are pushed out together with the ink toward the center of the pressure chamber 38 and collected around the protrusion 34 as shown in FIG. At this time, even if the bubble A staying above the pressure chamber 38 is very small, the flexible portion K is pushed out together with the ink to the protruding portion 34 side by contacting the bottom surface 33a. Further, as shown in FIG. 9, the flexible portion K comes into contact with the upper surface of the protrusion 34 and closes the discharge hole 35.

  Even after the flexible portion K comes into contact with the protrusion 34, the suction pump P2 continues to be driven, whereby the inside of the third flow path 39 provided downstream of the choke valve B is further decompressed. Then, the suction pump P2 is continuously driven for a predetermined time, and after the negative pressure is accumulated downstream of the choke valve B, the drive of the pressure pump P1 is started. Then, the ink is pushed out from the cartridge C, and the pushed-out ink is pressure-fed into the pressure chamber 38 via the first flow path 31 and the second flow path 32. When ink flows into the pressure chamber 38, as shown in FIG. 11, the central portion of the flexible portion K is opened away from the projection 34, and the negative pressure is accumulated in the flow chamber where the negative pressure is accumulated. Ink flows in at once. Then, the bubbles A collected around the protrusions 34 are pushed out to the ejection holes 35 together with the ink having an increased flow velocity. At this time, the bubbles A are expanded by the negative pressure accumulated in the downstream flow path, and are easily discharged from the flow path. In addition, ink having an increased flow velocity flows into the third flow path 39, the conduit in the ink supply tube 22, and the flow path in the recording head 5, and bubbles staying in each flow path, thickened ink, and the like are present. The ink is discharged from the nozzle N of the recording head 5. In this way, so-called choke cleaning is performed, and by repeating this choke cleaning, it is possible to prevent the growth of bubbles staying in the pressure chamber 38.

According to the above embodiment, the following effects can be obtained.
(1) According to the above embodiment, in the middle of the ink flow path formed in the first and second supply members 11 and 12, the pressure chamber 38 in which a part of the wall surface is constituted by the film F1, and the pressure chamber A choke valve B having a protrusion 34 formed on the bottom surface 33a of 38 is provided. The film F1 (flexible part K) that closes the pressure chamber 38 is made of a material that is displaced by the pressure inside and outside the pressure chamber 38. Accordingly, by driving the suction pump P2 of the maintenance mechanism 25, the ink is sucked and discharged from the nozzles N of the recording head 5, thereby reducing the pressure in the flow path and the pressure chamber 38 and bringing the flexible portion K into contact with the protrusion 34. Thus, the ink flow path can be closed. Then, by continuing to drive the suction pump P2, it is possible to accumulate negative pressure in the flow path downstream of the pressure chamber 38. Further, by driving the pressure pump P1, the ink is pumped to the pressure chamber 38, the flexible portion K is separated from the projection 34, and the ink is sent to the downstream ink flow path in which the negative pressure is accumulated. Can do. For this reason, it is possible to perform so-called choke cleaning in which bubbles in the ink flow path including the recording head 5, ink having increased viscosity, and the like are discharged from the nozzle N together with ink having an increased flow velocity. For this reason, without using an electromagnetic control valve or the like, the apparatus can be prevented from being enlarged, and the choke cleaning can be easily performed.

  Moreover, the pressure chamber 38 is formed on an inclined surface such that the bottom surface 33a facing the flexible portion K becomes smaller as the relative distance from the flexible portion K decreases as the distance from the protrusion 34 increases. That is, since the peripheral portion of the bottom surface 33a has a small relative distance to the flexible portion K, when the flexible portion K is displaced as the ink in the pressure chamber 38 is reduced, the flexible portion K is in close contact with the peripheral portion of the bottom surface 33a. Bubbles staying upward in the vertical direction can be pushed out to the protrusion 34 side. Therefore, when the pressure pump 38 is driven to supply ink into the pressure chamber 38 and the choke valve B is opened, the air bubbles A gathered around the protrusion 34 are discharged together with the ink whose flow velocity is increased. It can be easily discharged from the hole 35. For this reason, printing defects such as missing dots can be prevented.

  (2) In the above embodiment, the bottom surface 33 a of the pressure chamber 38 is provided with the protrusion 34 through which the discharge hole 35 is formed. For this reason, the film F1 (flexible portion K) provided so as to close the opening of the pressure chamber 38 is displaced according to the increase or decrease of the ink in the pressure chamber 38, so that the discharge hole 35 can be easily opened and closed. it can.

  (3) In the said embodiment, each choke valve B is provided in the 1st and 2nd supply members 11 and 12 so that the flexible part K may follow a perpendicular direction. For this reason, the effect can be exhibited particularly when the bubbles A are likely to stay above the pressure chamber 38 in the vertical direction.

  (4) In the above embodiment, the bottom surface 33a of the pressure chamber 38 is formed as an inclined surface where the relative distance from the flexible portion K decreases continuously as the distance from the protrusion 34 increases. For this reason, compared with the case where the level | step difference surface etc. are formed in the bottom face 33a, the flexible part K becomes easy to closely_contact | adhere to the bottom face 33a, and it can push out a bubble to the protrusion 34 side easily.

In addition, you may change this embodiment as follows.
In the above embodiment, the protrusion 34 of the circular recess 33 may be omitted. In this case, the discharge hole 35 opens at the bottom surface 33a of the circular recess 33, and the flexible portion K is fixed in a state where the discharge hole 35 opened at the bottom surface 33a can be closed.

  In the above embodiment, the protrusion 34 of the circular recess 33 may be provided at a place other than the center of the circular recess 33. At this time, the bottom surface 33a of the circular recess 33 is inclined toward the protrusion 34 from the corner where the bubbles are likely to stay. Moreover, the circular recessed part 33 is not restricted to a circle, You may form in another shape.

  In the above embodiment, as shown in FIG. 12, the bottom surface 33a of the circular recess 33 may have an inclined surface only in the semicircular portion on the upper side in the vertical direction. Even in this case, the air bubbles staying in the vertical direction can be pushed out to the protrusion 34 side.

  In the above embodiment, the discharge hole 35 constituting the discharge unit may not be opened at the wall surface (the bottom surface 33a in the above embodiment) facing the flexible portion K. For example, as shown in FIG. 13, the discharge hole 35 may be opened at a side surface that does not face the flexible portion K among the wall surfaces of the concave portion 50 constituting the pressure chamber 38. In this case, it is preferable that the discharge hole 35 is provided vertically below. The bottom surface 52 facing the flexible portion K is formed such that the relative distance from the flexible portion K decreases as the distance from the discharge hole 35 increases. At this time, the bottom surface 52 is preferably configured such that the region on the upper side in the vertical direction has a small relative distance to the flexible portion K, and the region on the lower side in the vertical direction has a large relative distance to the flexible portion K. Therefore, when the flexible portion K is displaced so as to approach the bottom surface 52, the flexible portion K on the upper side in the vertical direction and the bottom surface 52 are brought into close contact with each other, and the retained bubbles can be discharged.

In the above embodiment, the choke valve B is provided so that the film F is arranged along the vertical direction, but may be provided so that the film F is arranged along the horizontal direction.
-In above-mentioned embodiment, although the choke valve B was provided in the middle of the 1st and 2nd supply members 11 and 12, you may provide in other places. Further, the ink flow path for supplying ink from the cartridge C to the recording head 5 does not have to be provided with the flow paths formed in the first and second supply members 11 and 12, and may be a tube or the like.

  The films F1 and F2 may be any soft material that can detect a decrease or increase in ink in the pressure chamber 38, and is not limited to a thermoplastic resin. It may be fixed to the first and second supply members 11 and 12 with an adhesive or the like.

  In the above embodiment, the pressure pump P1 may be omitted, the cartridge C may be disposed above the choke valve B and the recording head, and ink may be supplied downstream from the cartridge C due to a water head difference.

In the above embodiment, the printer 1 (liquid ejecting apparatus) may be configured to include one choke valve B or a configuration including a plurality other than six.
In the above embodiment, the printer 1 that ejects ink has been described as the liquid ejecting apparatus, but other liquid ejecting apparatuses may be used. For example, printing apparatuses including fax machines, copiers, etc., liquid ejecting apparatuses that eject liquids such as electrode materials and coloring materials used in the production of liquid crystal displays, EL displays, and surface-emitting displays, and bio-organic materials used in biochip manufacturing It may be a liquid ejecting apparatus for ejecting a liquid or a sample ejecting apparatus as a precision pipette. Further, the choke valve B (valve mechanism) may be applied to an apparatus other than the liquid ejecting apparatus. Further, the fluid is not limited to ink, and may be applied to other fluids.

FIG. 3 is a perspective view of a main part of the printer according to the embodiment of the present invention. FIG. 2 is a schematic diagram of a main part of the printer. FIG. 2 is a schematic diagram of a main part of the printer. FIG. 3 is a schematic diagram of a maintenance mechanism provided in the printer. The front view of the 1st supply member with which the printer is equipped. The rear view of the 1st supply member. Sectional drawing of the principal part of the 1st supply member. The principal part front view of the 1st supply member. Sectional drawing of the principal part of the 1st supply member. The principal part front view of the 1st supply member. Sectional drawing of the principal part of the 1st supply member. Explanatory drawing of the choke valve of another example. Explanatory drawing of the choke valve of another example. Explanatory drawing of the conventional choke valve. Explanatory drawing of the conventional choke valve.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid ejecting apparatus, 5 ... Recording head as a liquid ejecting head, 11, 12 ... 1st and 2nd supply member as an outer member, 13 ... Communication hole which comprises a liquid supply path, 22 ... Liquid supply An ink supply tube constituting the path, 31... A first flow path constituting the liquid supply path, 32... A second flow path constituting the liquid supply path and the introduction portion, 33. Projecting part constituting the discharge part, 35... Liquid supply path and discharge hole constituting the discharge part, 38. Pressure chamber constituting the liquid supply path, 39... Third flow path constituting the liquid supply path, C. Cartridge as means, F ... film as flexible member, N ... nozzle, P1 ... pressure pump, P2 ... suction pump as suction means.

Claims (6)

Liquid storing means for storing liquid, liquid ejecting head for ejecting liquid from the nozzle, liquid supply path for communicating the liquid storing means and the liquid ejecting head, and suction for sucking liquid from the nozzle of the liquid ejecting head A liquid ejecting apparatus comprising:
A pressure chamber having a liquid introduction part and a discharge part in the middle of the liquid supply path,
Said pressure chamber, a part of the wall surface, Rutotomoni formed of a flexible member which is displaced with the pressure difference between the inside and the outside, facing the wall of the pressure chamber which faces said flexible member, from the discharge portion The distance between the flexible member and the flexible member decreases as the distance increases .
When the suction means sucks the liquid from the pressure chamber through the discharge portion, the flexible member is configured to be opposed to the opposite wall surface from a portion having a small relative distance to the opposite wall surface in the flexible member. The suction means is in contact with the discharge section so as to gradually close and close the discharge section, and the suction means is in contact with the discharge section in the liquid supply path. In addition, the liquid ejecting apparatus is configured to accumulate negative pressure in the flow path on the liquid ejecting head side and to be separated from the ejection unit when the liquid is pressure-fed into the pressure chamber through the introduction unit . The liquid ejecting apparatus according to claim 1,
In the liquid ejecting apparatus, the pressure chamber is formed such that a region on the upper side in the vertical direction of the facing wall facing the flexible member is reduced in relative distance from the flexible member. The liquid ejecting apparatus according to claim 1 or 2,
The liquid ejecting apparatus according to claim 1, wherein the facing wall surface facing the flexible member is formed on an inclined surface in which a relative distance to the flexible member continuously decreases as the distance from the discharge unit increases. The liquid ejecting apparatus according to any one of claims 1 to 3,
The liquid ejecting apparatus according to claim 1, wherein the discharge unit includes a protrusion formed on an opposite wall surface facing the flexible member, and a discharge hole opened on an upper surface of the protrusion. The liquid ejecting apparatus according to any one of claims 1 to 4,
The liquid ejecting apparatus according to claim 1, wherein the introduction portion that introduces the liquid into the pressure chamber from the liquid supply path is formed vertically below the pressure chamber. A pressure chamber having an inlet portion and a discharge portion of the liquid, the flexible member forming a part of the wall of the pre-Symbol pressure chamber is and away with respect to the discharge portion with the pressure difference between the inside and outside of the pressure chamber A valve mechanism for switching the communication state between the introduction part and the discharge part by displacing the valve,
The opposing wall surface of the pressure chamber facing the flexible member is formed such that the relative distance from the flexible member decreases as the pressure chamber separates from the discharge portion ,
When the liquid is sucked from the pressure chamber through the discharge part, the flexible member gradually comes into close contact with the opposing wall surface from a portion where the relative distance between the flexible member and the opposing wall surface is small. In this state, the liquid ejecting unit is in contact with the ejection unit so as to close the ejection unit and is in contact with the ejection unit with respect to the liquid ejecting head in the liquid supply path. The valve mechanism is characterized in that a negative pressure is accumulated in the flow path and the liquid is separated from the discharge portion when the liquid is pumped into the pressure chamber through the introduction portion .

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