JP2005161770A - Ink-jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet printer which enables the exhaust valve means capable of discharging air bubbles generated in an ink passage to be certainly operated with a simple structure. <P>SOLUTION: An ink carriage 9 is equipped with an air-bubbles reservoir chamber 27 in which the air-bubbles generated in the ink passage are held and an exhaust valve means 26 capable of discharging the air-bubbles in the air-bubbles reservoir chamber 27. The exhaust valve means 26 is equipped with a passage hole 56 having a communication opening 56a communicating with the exterior of the air-bubbles reservoir chamber 27 at one end of the passage hole and a valve 57 capable of moving along the axial line direction in the inside of the passage hole 56 so that the communication opening 56 may be made opened and closed. For the inner circumference of the passage hole 56 facing the outer one of the valve 57, the inside diameter of the part near the communication opening 56a is formed to the small diameter enabling the sliding-contact with the valve 57 while the inside diameter of the part far from the communication opening 56a being formed to the large diameter having a clearance between the valve 57 and the inside diameter. Thereby, even if a burr is generated in the valve 57, the hindrance of the air stream passage and/or the deterioration of the sliding performance caused by the burr can be inhibited. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet printer, and more particularly to a structure of an ink jet printer capable of storing bubbles generated in an ink flow path and discharging the bubbles.

  2. Description of the Related Art Conventionally, a tube supply type ink jet printer that supplies ink to a recording head mounted on a moving carriage from an ink tank that is stationary in an ink jet printer body via a flexible tube is known. . On the other hand, in the ink jet printer, if bubbles (air) are contained in the ink in the recording head, ink ejection failure and recording quality are deteriorated.

  In a tube supply type ink jet printer, it is inevitable that air permeates the tube and dissolves in the ink due to the characteristics of the material constituting the tube, and a bubble storage chamber is provided upstream of the recording head to remove bubbles. Work was necessary.

  As a technique for removing bubbles in the tube supply type ink jet printer, for example, Patent Document 1 includes a manifold (corresponding to a bubble storage chamber) above the recording head, and an ink tank and a circulation pump on the stationary position side. And a configuration in which bubbles are removed by driving a circulation pump is described. Specifically, the ink is circulated from the ink tank in the order of the first ink flow path, the manifold, the second ink flow path, and the ink tank, and the bubbles in the circulation path are returned to the ink tank and removed. Further, at the maintenance position, the ink is sucked from the nozzle (ink discharge) side of the recording head by the suction purge means.

  In the configuration of Patent Document 1, a tube for returning from the circulation pump to the ink tank is necessary for circulation, and there is a problem that the apparatus becomes large and complicated.

Patent Document 2 describes that air generated as bubbles in an ink supply tube is accumulated in an upper part of a tank mounted on a carriage, discharged by an exhaust pump, and after discharge, the tank is sealed by an exhaust valve. ing. The specific configuration of the exhaust valve is unknown.
JP 2000-103084 A (see FIG. 1) Japanese Patent Laid-Open No. 2002-240310 (see FIG. 5)

  The present inventor provides an exhaust valve means that enables the bubbles in the bubble storage chamber to be discharged by displacing the valve body in the passage hole communicating with the bubble storage chamber along the axial direction of the passage hole. developed.

  However, as the exhaust valve means, when the bubbles in the bubble storage chamber are not exhausted (for example, when recording on a recording medium, etc.), the communication port is securely closed, and ink or bubbles are discharged into the bubble storage chamber. While it is necessary to store stably, at the time of maintenance, it is desired that the communication port be quickly communicated with the outside so that the air in the bubble storage chamber can be efficiently discharged.

  Further, since the exhaust valve means is mounted on the carriage, it reciprocates in the main scanning direction together with the carriage during recording. Therefore, the exhaust valve means is also required to have a simple structure for size reduction and weight reduction.

  The present invention solves such problems and provides an ink jet printer capable of reliably operating an exhaust valve means capable of discharging bubbles generated in an ink flow path with a simple structure. It is the purpose.

  In order to achieve the above object, an ink jet printer according to an embodiment of the present invention includes a carriage on which a recording head for recording ink on a recording medium by discharging ink from nozzles, and ink supplied to the recording head. In the ink jet printer comprising an ink tank for storing ink and an ink flow path for supplying ink from the ink tank to the recording head, the carriage includes a bubble storage chamber for storing bubbles generated in the ink flow path. And an exhaust valve means capable of discharging bubbles in the bubble storage chamber. The exhaust valve means has a passage hole having one end communicating with the outside of the bubble storage chamber, and opens and closes the communication opening. A valve body capable of displacing the inside of the passage hole along the axial direction of the passage hole, the inner circumference of the passage hole facing the outer periphery of the valve body. In other words, the inner diameter of the portion close to the communication port is formed to be a small diameter that can slide in contact with the valve body, and the inner diameter of the portion far from the communication port is formed to be a large diameter having a gap between the valve body. It is a feature.

  According to a second aspect of the present invention, in the ink jet printer according to the first aspect, the valve body is a molded body of a rubber-like elastic material.

  According to a third aspect of the present invention, in the ink jet printer according to the second aspect, a portion of the inner periphery of the passage hole facing the outer periphery of the valve body that is far from the communication port is a burr generating portion in the valve body. It is the part which opposes, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the ink jet printer according to any one of the first to third aspects, the valve body is urged toward the communication port side, and the surface of the valve body facing the communication port is disposed on the surface. In addition, an annular protrusion that surrounds the communication port is provided.

  According to a fifth aspect of the present invention, in the ink jet printer according to any one of the first to fourth aspects, the valve body is separated from the communication port by an insert inserted from the outside into the communication port. It is characterized by being displaced.

  According to the first aspect of the present invention, the valve body is configured to displace the inside of the passage hole along the axial direction thereof to open and close the communication port. Thus, the exhaust valve means for discharging to the outside can be realized in a small and simple manner.

  In addition, the inner diameter of the portion of the passage hole facing the outer periphery of the valve body, which is close to the communication port, is formed with a small diameter that allows sliding contact with the valve body. In addition to being able to guide the opening of the mouth, an air flow path can be secured between the outer periphery of the valve element and the inner periphery of the passage hole when the communication port is opened. Furthermore, in the inner periphery of the passage hole facing the outer periphery of the valve body, the inner diameter of the portion far from the communication port is formed in a large diameter with a clearance between the valve body, The shape of the portion far from the communication port can prevent the air flow path in the passage hole from being hindered and the slidability of the valve body from being impaired.

  According to the second aspect of the present invention, since the valve body is a rubber-like elastic material, the sealing performance of the valve body with respect to the communication port can be enhanced by utilizing the elastic deformation. Moreover, the number of parts can be reduced by combining the valve function that the valve body opens and closes the communication port and the sealing function. Furthermore, since the valve body is a molded body, the manufacturing cost can be reduced.

  According to the third aspect of the present invention, since the valve body is a molded body of rubber-like elastic material, even if burrs are generated in the valve body due to the joint of the mold, the burr generating portion The part of the passage hole that faces the gap is formed in a large diameter with a gap, so that the air flow path of the passage hole is hindered by the burr, and the slidability of the valve element is impaired. Can be prevented.

  According to the fourth aspect of the present invention, the valve body is urged toward the communication port, the surface of the valve body that faces the communication port covers the communication port, and the protrusion surrounds the communication port. The communication port can be reliably closed.

  According to the invention described in claim 5, since the valve body is displaced so as to be separated from the communication port by the insert inserted from the outside into the communication port, a gap is generated between the valve body and the communication port. Thus, the flow path for discharging the air in the bubble discharge passage to the outside can be easily and reliably formed.

  Next, an embodiment embodying the present invention will be described. As shown in FIG. 1, an ink jet printer 100 includes a recording mechanism unit 2 that performs recording by ejecting ink onto a sheet P that is a recording medium and is included in a main body frame 1, and a recording head unit 3 in the recording mechanism unit 2. A maintenance unit 4 that performs maintenance processing, and ink tanks 5a to 5d that store ink to be supplied to the recording head unit 3 that is fixedly disposed in the main body frame 1 are configured.

  A plurality of ink tanks 5 for full-color recording (reference numerals 5a to 5d are assigned to ink tanks for individual colors, that is, black, cyan, magenta, and yellow, see FIG. 1). Can be exchanged accordingly.

  In the recording mechanism unit 2, a carriage 9 is slidably mounted on a left and right rear guide shaft 6 and a front guide shaft 7 provided in parallel in the main body frame 1, and the recording head unit is mounted on the carriage 9. 3 is integrally attached.

  A carriage drive motor 10 disposed on the right rear side of the main body frame 1 and a timing belt 11 which is an endless belt are configured so that the carriage 9 can reciprocate in the left and right directions along the front and rear guide shafts 6 and 7. Yes. On the other hand, although not shown, the paper P is transported horizontally (in the direction of arrow A in FIG. 1) in a direction perpendicular to the moving direction of the carriage 9 on the lower surface side of the recording head unit 3 by a known paper transport mechanism. .

  Outside the width of the sheet P to be conveyed, an ink receiving portion 12 is provided on one end side (the left end portion in FIG. 1 in the embodiment), and a maintenance unit 4 is disposed on the other end side. Yes. As a result, the recording head unit 3 periodically discharges ink to prevent nozzle clogging at the flushing position where the ink receiving portion 12 is provided, and receives ink at the ink receiving portion 12 during the recording operation. . At the head standby position on the other end side, the maintenance unit 4 is arranged to clean the nozzle surface, and to perform a recovery process for selectively sucking ink for each color and bubbles (in the damper device 13 described later) Remove the air).

  As shown in FIG. 1, the ink tank 5 for each individual color can be inserted and mounted from the front at a position below the nozzle surface on the lower surface of the recording head unit 3. In FIG. 1, in order from the left, an ink tank 5a for black ink (BK), an ink tank 5b for cyan ink (C), an ink tank 5c for magenta ink (M), and an ink tank for yellow ink (Y). 5d is arranged horizontally and in parallel.

  On the rear side of each ink tank mounting portion, a hollow needle for ink supply (not shown) protrudes horizontally so as to face the insertion direction (rear side wall surface) of each color ink tank 5. The proximal end portion of the hollow needle corresponding to each color ink is connected to the recording head unit 3 via the corresponding flexible ink supply tubes 14a to 14d. In this case, the middle portions of the black and cyan ink supply tubes 14a and 14b and the middle portions of the magenta and yellow ink supply tubes 14c and 14d are stacked one above the other.

  Next, an embodiment of the recording head unit 3 mounted on the carriage 9 will be described with reference to FIGS. In the present embodiment, the recording head unit 3 is fixed to the lower surface side of the box-shaped head holder 20 and the bottom plate 20a of the head holder 20 for full color recording as shown in FIGS. An ink jet recording head 21, a damper device 13 and an exhaust valve means 26 fixed to the upper side of the bottom plate 20 a are provided.

  On the lower surface of the recording head 21, a row of black ink (BK) nozzles 22a, a row of cyan ink (C) nozzles 22b, and a yellow ink are shown from the left side in FIG. The row of nozzles 22c for ink (Y) and the row of nozzles 22d for magenta ink (M) are formed long in a direction perpendicular to the moving direction (main scanning direction) of the carriage 9. Each nozzle 22 is exposed downward so as to face the upper surface of the paper P.

  The recording head 21 has an ink supply port for each ink color (for example, four colors) on one side of the upper surface, similar to those known in JP-A-2002-67312, JP-A-2001-219560, and the like. Ink is distributed to a number of pressure chambers via ink supply channels extending from the supply port, and ink is ejected from the nozzles 22 by driving actuators 23 such as piezoelectric elements corresponding to the pressure chambers. . A flexible flat cable 24 for applying a voltage to the actuator 23 is fixed to the upper surface of the actuator 23. Each ink supply port of the recording head 21 is formed with an ink channel through which ink is supplied from each ink tank 5 via the damper device 13.

  Next, based on FIGS. 3-8, the structure of the damper apparatus 13 is explained in full detail. The damper device 13 includes a plurality of independent damper chambers 27 as bubble storage chambers for each ink color, which are partitioned by sub-partition walls 35a and 30 across the main partition wall 35 and intersecting the main partition wall. . In the embodiment, a part of a black ink (BK) damper chamber 27a is disposed under the main partition wall 35, and a cyan ink (C) damper chamber 27b and a yellow ink (Y ) Damper chamber 27c and magenta ink (M) damper chamber 27d are partitioned and arranged by sub-partition walls 35a and 30, and are configured in two layers vertically.

  Specifically, the main body case 25 in the damper device 13 has a rectangular tubular side wall as an outer periphery, and is fixed so as to cover a box-shaped lower case 32 having an open top and bottom surface and an upper surface of the lower case 32. An upper case 31 is included. Both the upper case 31 and the lower case 32 are injection-molded with a synthetic resin material and are liquid-tightly coupled by ultrasonic welding or the like.

  The lower case 32 is provided with an opening on the lower surface thereof that opens most of the area of the lower surface, and a main partition wall 35 is formed at a position spaced in parallel from the opening and the upper opening surface. ing. The opening is sealed with a damper flexible film (synthetic resin film that is impermeable to air and liquid) 36. Specifically, the outer peripheral edge of the flexible film 36 is bonded to the lower end surface of the outer peripheral wall 37 that defines the outer periphery of the opening by bonding or ultrasonic welding. Between the flexible film 36 and the main partition wall 35, a first chamber 27a-1 of a damper chamber for black ink (BK) is formed. A gap for deformation of the flexible film 36 is secured between the flexible film 36 and the bottom plate 20 a of the head holder 20, and the damper device 13 is fixed to the head holder 20.

  On the upper surface of the main partition wall 35, a sub-partition wall 35a that rises integrally with the main partition wall 35 is formed, and a portion above the main partition wall 35 in the lower case 32 is described later. A plurality of damper chambers are formed in cooperation with the upper case 31. In the embodiment, two sub-partition walls 35a are spaced apart from each other, and together with the side wall of the lower case 32, 3 for cyan ink (C), yellow ink (Y), and magenta ink (M) are used. Individual damper chambers 27b to 27d (specifically, second chambers 39b to 39d of the damper chamber) are formed. As shown in FIG. 6, each of the sub partition walls 35 a is formed extending over the entire length of the lower case 32, and the damper chambers 27 b to 27 d (specifically, the second chambers 39 b to 39 b) at positions away from the upper surface of the main partition wall 35. 39d) communicates with the ink outlets 41b to 41d for each ink color.

  Further, an additional sub partition wall 35 b is formed extending to a position off the upper surface of the main partition wall 35 in the vicinity of the ink outlets 41 b to 41 d, and between the sub partition wall 35 b and the side wall of the lower case 32, black A second chamber 39a of a damper chamber for ink (BK) is formed. The lower end of the second chamber 39a communicates with the ink outlet 41a (see FIGS. 3 and 6).

  The first chamber 27a-1 of the damper chamber for black ink (BK) passes through the passage 42 as a constricted portion penetrating the second chamber 39a in the vertical direction through the cylindrical portion formed along the sub partition wall 35b. It is communicating (refer FIG.5, FIG.6, FIG.8 (c)). The passage 42 is formed to have a cross-sectional area smaller than that of the first chamber 27a-1, and the flow path resistance is set to be larger than that in the first chamber 27a-1.

  The upper case 31 is formed in a flat shape having a plurality of recesses on the upper surface. The upper case 31 includes cyan ink (C) and yellow ink (which are partitioned by two sub-partition walls 30 at an upper position substantially corresponding to the first chamber 27a-1 of the damper chamber for black ink (BK). The first chambers 27b-1 to 27d-1 of the three damper chambers 27b to 27d for Y) and magenta ink (M) are formed open upward (see FIG. 4). The sub partition wall 30 is located on the extended surface of the sub partition wall 35a of the lower case 32, and a plurality of passage holes 44 as throttle portions are formed in the bottom wall 29 of the first chambers 27b-1 to 27d-1. The first chambers 27 b-1 to 27 d-1 are formed so as to penetrate vertically, and the first chambers 27 b-1 to 27 d-1 individually communicate with the lower chamber (the chamber partitioned by the sub-partition wall 35 a in the lower case 32), that is, the second chambers 39 b-39 d. doing.

  The passage hole 44 is formed to have a smaller cross-sectional area than each of the first chambers 27b-1 to 27d-1, and the flow path resistance is set larger than that of each of the first chambers 27b-1 to 27d-1.

  The upper open surfaces of the first chambers 27 b-1 to 27 d-1 are commonly sealed with a single flexible film 43 for damper (made of synthetic resin and impermeable to air and liquid). Specifically, the flexible film 43 is bonded to the outer peripheral wall defining the outer periphery of each first chamber and the upper end surface of the sub partition wall 30 by adhesion or ultrasonic welding.

  As shown in FIG. 5, the ink outlets 41 a to 41 d are arranged side by side on the lower surface of the lower case 32, and are opened downward at positions extending downward from the flexible film 36. On the other hand, the recording head 21 has a plurality of ink supply ports (not shown) communicating with the end portions of the ink supply channels (manifolds) for the respective ink colors on the upper surface at positions facing the respective ink outlets 41a to 41d. ing. Each of the ink outlets 41a to 41d passes through an opening provided in the bottom plate 20a of the head holder 20, and communicates with each ink supply port of the recording head 21 via a sealing material such as rubber packing.

  As shown in FIGS. 3 and 4, an ink inlet 47 for each ink color (four in the embodiment) is provided in a portion 32a protruding in a flange shape from the side surface of the lower case 32 opposite to the ink outlets 41a to 41d. Ink inlets for black ink (BK), cyan ink (C), yellow ink (Y), and magenta ink (M) are indicated by 47a, 47b, 47c, and 47d, respectively, and are opened upward. ing.

  A joint member 45 having an ink flow path for each ink color is connected to these ink inflow ports via a seal 46 such as a packing in correspondence with the lower end of each ink flow path. The top ends of the ink supply tubes 14 a to 14 d for the respective ink colors are connected to the upper ends of the ink flow paths of the joint member 45.

  The ink inlet 47a for the black ink (BK) is connected to the first chamber of the corresponding damper chamber 27a via a concave passage 48 formed horizontally downward in the lower surface of the lower case 32. ing. The other ink inlets 47b to 47d are formed in the vertical direction (with respect to the surface formed by the main partition wall 35) along the concave passage 48 formed horizontally downward in the lower surface of the lower case 32 and one side wall of the lower case 32. It is connected to corresponding first chambers of damper chambers 27b to 27d via a communication passage 49 formed so as to extend in a substantially orthogonal direction and a communication passage 50 penetrating vertically through the upper case 31 (FIG. 4, FIG. 5, FIG. 7 (a), FIG. 7 (b) and FIG. 8 (b)). As the carriage 9 reciprocates in the main scanning direction (left-right direction) in accordance with the recording operation, each ink supply tube 14 also moves in the left-right direction. The pressure also varies greatly, and the pressure variation propagates to each damper chamber 27 via the ink inlet 47. In the present embodiment, since the opening surface of the communication path 50 is at a height position close to the lower surface of the flexible film 43, the ink that has flowed into the damper chambers 27 b to 27 d faces the opening surface of the communication path 50. Thus, it is possible to directly collide with the approaching flexible film 43, so that the dynamic pressure fluctuations of the ink in the ink supply tubes 14b to 14d can be efficiently absorbed (damped).

  The open lower surfaces of the ink inflow ports 47a to 47d and the concave passage 48 are sealed with portions where the flexible film 36 is extended.

  A U-shaped rib 35c in plan view with both ends connected to the side wall on the concave passage 48 side is flexible on the ceiling surface of the first chamber 27a-1 of the damper chamber for black ink (BK), that is, the lower surface of the main partition wall 35. The height of the conductive film 36 is not reached. For this reason, the space surrounded by the U-shaped rib 35c is provided with a space in which the ink does not enter, and the pressure variation of the ink described above is absorbed together with the air and the flexible film 36 therein. Yes.

  In addition, third chambers 55a to 55d of the damper chambers are formed in the upper surface of the upper case 31 so as to be independent of each other at positions corresponding to the second chambers 39a to 39d in the vicinity of the ink outlets 41a to 41d. Has been. Each of the third chambers 55a to 55d communicates with the corresponding second chamber 39a to 39d through an air hole 54 formed through the upper case 31. That is, the damper chambers 27a to 27d for each ink color are each composed of three chambers from the first chamber to the third chamber.

  Further, the upper case 31 is formed with an exhaust hole 53 communicating with the upper part of each of the second chambers 39a to 39d between the first chamber and the third chamber. The upper ends of the exhaust holes 53 are respectively connected to a plurality of exhaust passages 51 that are recessed in the upper surface of the upper case 31 independently of each other, and the exhaust passages extend in the longitudinal direction of the main body case (the ink inflow ports 47a to 47d). The other end extends in a direction orthogonal to the direction in which the ink outlets 41a to 41d are connected) and is connected to connection ports 52a, 52b, 52c, and 52d for the exhaust valve means 26 described later (see FIG. 4).

  Each exhaust hole 53 is formed in a cylindrical wall that hangs down from the upper case 31 into each of the second chambers 39a to 39d, and opens into each of the second chambers 39a to 39d at a predetermined distance from the upper case 31. ing. That is, as will be described later, even when the air bubbles in the second chambers 39a to 39d are discharged from the exhaust hole 53, an air layer corresponding to the hanging height of the cylindrical wall is secured above the second chambers 39a to 39d. ing. In addition, since air layers are normally secured in the third chambers 55a to 55d, the pressure fluctuations generated in the damper chambers 27a to 27d are absorbed and relaxed by these air layers, and the nozzles 22 of the recording head 21 are absorbed. The pressure is maintained uniformly to improve the recording quality.

  The third chambers 55a to 55d and the exhaust passages 51 of the respective damper chambers are covered with open portions of the flexible film 43, and the respective chambers and passages are defined.

  The damper device 13 is fixed on the carriage 9 so that the main partition wall 35 and the flexible films 36 and 43 extend in parallel with the moving direction of the carriage 9, that is, in parallel with the nozzle opening surface of the recording head 21. .

  Next, the exhaust valve means 26 will be described. The storage portion 34 provided integrally on one side of the lower case 32 (the right end in FIGS. 4 and 8A) has a substantially cylindrical shape that is long in the vertical direction. In addition, (four) passage holes 56 that open vertically are formed for each ink color. The side edge of the upper case 31 extends to a position covering the upper end of the storage portion 34, and the other end of each exhaust passage 51 is individually communicated with the upper end opening of each passage hole 56. The lower end opening of the passage hole 56 is a communication port 56a that communicates with the outside.

  Inside the passage hole 56, there are provided a valve body 57 that can be displaced along the axial direction of the passage hole 56, and a spring means 60 (coil spring or the like) as means for urging the valve body 57 toward the communication port 56 a. It has been. The valve body 57 has a substantially cylindrical shape, and an annular protrusion 57a surrounding the communication port 56a is provided on a surface facing the communication port 56a. The valve body 57 is formed of a rubber-like elastic material, and the protrusion 57a is brought into close contact with the surface around the communication hole 56a due to the elasticity of the rubber so that a valve closed state described later is obtained. ing.

  In the production of a rubber molded body, a mold is used. Generally, however, burrs are generated in the molded body due to the joint of the mold (such as a nest and a slide portion). The valve body 57 of the present embodiment has an extremely small size (diameter of about 3 mm). In such a small-sized molded body, the mold is devised so as to reduce the burr or the generated burr is post-processed. It is not easy to remove it with this, which leads to an increase in the cost of parts. The valve body 57 of the present embodiment is not obtained by taking a special countermeasure against burrs, but is obtained by a general manufacturing method. The upper end side (the side far from the communication port 56a) of the outer peripheral surface of the valve body 57 is provided. It becomes a burr generation part 57b, and the burr spreads in an edge shape toward the outer peripheral side.

  In the inner periphery of the passage hole 56 that faces the outer periphery of the valve element 57, the inner diameter of the portion close to the communication port 56a is formed in a small diameter that allows sliding contact with the valve element 57, and is far from the communication port 56a. The inner diameter of the portion is formed to be a large diameter having a gap with the valve body 57 (hereinafter, the small diameter portion is referred to as a small diameter portion 56b and the large diameter portion is referred to as a large diameter portion 56c). The large-diameter portion 56c is a portion facing the burr generating portion 57b in the valve body 57 described above. That is, when the valve body 57 is displaced upward from the position of the inner peripheral surface of the passage hole 56 facing the burr generating portion 57b when the valve body 57 is at the lowest position (bottom side) of the passage hole 56, A portion up to the position of the inner peripheral surface of the passage hole 56 facing the burr generating portion 57b is formed as at least a large diameter portion 56c.

  In this embodiment, as shown in FIG. 9 (b), in the valve body 57, most of the diameter excluding the burr generating part 57b is D0, and the diameter of the burr generating part 57b is D1 (> D0). ing. When the inner diameter of the small diameter portion 56b of the passage hole 56 is D2, and the inner diameter of the large diameter portion 56c is D3, the relationship is D0 <D2 <D1 <D3. The inner diameter D3 of the large-diameter portion 56c is set according to the degree of spreading of the burr generated in the valve body 57 in the outer peripheral direction. 9A and 9B, the upper surface of the valve body 57b is provided with an engaging portion 57c projecting for attaching the spring means 60. The shape for attaching is not limited to the protruding shape as shown in the figure.

  A state in which the valve body 57 is pressed downward by the spring means 60 is a valve closed state with respect to the communication port 56a (see FIG. 8A and FIG. 9A). A state in which the cap member 72 is pushed upward by the insert 72a is a valve open state with respect to the communication port 56a (see FIG. 9B).

  The maintenance unit 4 includes a cap member 71 that covers the opening surface of the nozzle 22 of the recording head 21 so as to be openable and closable, and a plurality of small cap members 72 that cover the lower end opening surface of the exhaust valve means 26 so as to be individually openable and closable (see FIG. 8 (a)). Both cap members 71 and 72 are moved upward and downward of the nozzle 22 and the exhaust valve means 26 when the carriage 9 is moved to the standby position (right end position in FIG. 1) by a vertical movement mechanism 73 similar to a known maintenance unit. It rises so as to be in close contact with the lower end surface, and descends so as to be separated from those surfaces at other positions. Further, the cap member 71 is connected to the suction pump 74 in the same manner as a known maintenance unit, and the ink and foreign matters that are thickened from the nozzles 22 are removed by suction by driving the suction pump 74.

  Each small cap member 72 has an insertion body 72a protruding from the cap member. When the small cap member 72 comes into close contact with the lower end surface of the exhaust valve means 26, the insertion body 72a causes the valve body 57 to be biased by the spring means 60. Push up against the valve to open the valve.

  Each small cap member 72 is connected to the suction pump 74 through a common flow path, and the bubbles accumulated in the second chambers 39a to 39d of the damper chambers are collectively sucked by driving the suction pump 74. Discharged. This is because the ink supplied from the ink tank 5 to the recording head 21 through the ink supply tube 14 is temporarily stored in the second chambers 39a to 39d in the middle of the ink flow path, thereby separating the bubbles from the ink. The air bubbles that have floated and accumulated in the upper portions of the second chambers 39a to 39d are discharged by the suction pump 74 as described above.

  The cap member 71 and the small cap member 72 are alternatively connected to the suction pump 74 by a switching valve 75. The cap member 71 and the small cap member 72 are simultaneously brought into close contact with the opening surface of the nozzle 22 and the lower end surface of the exhaust valve means 26 by the vertical movement mechanism 73. Preferably, the second chamber is firstly passed through the small cap member 72. The bubbles accumulated in the upper portions of 39a to 39d are discharged, and then the ink is discharged from the nozzle 22 through the cap member 71. If the cap member 71 alone is used to discharge the bubbles in the second chambers 39a to 39d, a large amount of ink must be discharged. However, by doing the above, the bubbles can be discharged and recorded with a small ink discharge amount. Head recovery processing can be performed.

  In addition, only ink suction from the nozzles 22 or only discharge of bubbles in the second chambers 39a to 39d can be performed independently.

  In the above embodiment, when the recording head 21 is not at the position of the maintenance unit 4, that is, when ink is ejected to the recording medium, the small cap member 72 is inserted into the communication port 56 a of the passage hole 56. 72a is not inserted. Therefore, the state in which the valve body 57 is pressed and clamped between the spring means 60 and the bottom surface of the passage hole 56 is maintained. At this time, since the protrusion 57a of the valve body 57 is pressed toward the communication port 56a and elastically deforms, it surrounds the periphery of the communication port 56a without coming into contact with one another, and is in close contact with the surrounding surface. Thereby, the communication port 56a can be reliably closed. Ink and bubbles in the damper chamber 27 are not discharged through the exhaust passage 51 and are stably stored.

  On the other hand, when the recording head 21 is at the position of the maintenance unit 4 and the insertion body 72 a of the small cap member 72 is inserted into the communication port 56 a of the passage hole 56 from below, the valve body 57 is along the axial direction of the passage hole 56. And is separated from the communication port 56a, and a gap is formed between the lower surface of the valve element 57 and the protrusion 57a and the communication port 56a.

  The diameter D3 of the large-diameter portion 56c is set in advance to be larger than the diameter D1 of the burr generating portion 57b of the valve body 57 (D3> D1). As a result, a gap is also formed between the outer periphery of the valve body 57 and the inner periphery of the passage hole 56.

  Accordingly, these gaps serve as air flow paths in the passage hole 56, and the air bubbles in the damper chamber 27 are discharged from the exhaust passage 51, the passage hole 56, and the communication port 56a by the suction of the suction pump 74 through the small cap member 72. Surely discharged through.

  Further, when the valve body 57 is again in the valve closed state, the valve body 57 is guided by the small diameter portion 56b together with the urging force of the spring means 60 and displaced downward, so that the communication port 56a is quickly closed. be able to.

  As described above, in the present invention, the passage hole 56 is provided with the large-diameter portion 56c having the diameter D3 larger than the diameter D1 of the burr generating portion 57b, and the burr of the valve body 57 contacts the inner peripheral surface of the passage hole 56. Since they are not in contact with each other, the burrs do not cause inconvenience that the slidability of the vertical movement of the valve body 57 is deteriorated or the air flow path in the passage hole 56 is narrowed.

  Therefore, in the manufacture of the valve body 57, there is no need to take measures to reduce or eliminate the burr, and there is no fear of raising the cost of parts of the valve body 57.

  In this embodiment, since the valve body 57 itself is formed of a rubber-like elastic material, the valve function and the sealing function can be used together, and the cost can be reduced, the weight can be reduced, and the size can be reduced by reducing the number of parts. it can.

  Instead of the suction operation of the suction pump 74 as in this embodiment, positive pressure is applied to the ink from the ink tank 5 side to suck and remove thickened ink and foreign matter from the nozzle 22, or the second chamber. The bubbles 39a to 39d can also be discharged. Alternatively, the suction operation and the positive pressure application to the ink can be used in combination.

  Needless to say, the present invention can be applied to various types of inkjet printers.

It is a top view of the recording mechanism part of an inkjet printer. It is a bottom view of a head holder. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. It is a top view of the damper device in the state where the flexible membrane 43 of the first embodiment is removed. It is a bottom view of a damper device in the state where flexible membrane 36 is removed. It is a top view of a lower case. (A) is a plan view of only the upper case, and (b) is a bottom view of only the upper case. (A) is a sectional view taken along line VIIIa-VIIIa in FIG. 4, (b) is a sectional view taken along line VIIIb-VIIIb in FIG. 4, and (c) is a sectional view taken along line VIIIc-VIIIc in FIG. (A) It is sectional drawing which shows the valve closed state in an exhaust valve means, (b) It is sectional drawing which shows a valve open state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 Carriage 13 Damper apparatus 20 Head holder 21 Recording head 22 Nozzle 25 Main body case 26 Exhaust valve means 27, 27a-27d Damper chamber 34 Storage part 35 Main partition wall 44 Passage hole 51 Exhaust passage 56 Passage hole 56a Communication port 56b Small diameter part 56c Large diameter portion 57 Valve body 57a Protruding portion 57b Burr generating portion 60 Spring means 71 Cap member 72 Small cap member 72a Insert body 74 Suction pump

Claims (5)

A carriage mounted with a recording head for recording on a recording medium by discharging ink from nozzles, an ink tank for storing ink supplied to the recording head, and an ink flow for supplying ink from the ink tank to the recording head Ink jet printer with road,
The carriage includes
A bubble storage chamber for storing bubbles generated in the ink flow path;
An exhaust valve means capable of discharging the bubbles in the bubble storage chamber is mounted,
The exhaust valve means includes
A passage hole having at one end a communication port communicating with the outside of the bubble storage chamber;
A valve body capable of displacing the inside of the passage hole along the axial direction of the passage hole so as to open and close the communication port,
Of the inner periphery of the passage hole facing the outer periphery of the valve body, the inner diameter of the portion close to the communication port is formed to be a small diameter that can be slidably contacted with the valve body, and the inner diameter of the portion far from the communication port is An ink jet printer having a large diameter with a gap therebetween.   The ink jet printer according to claim 1, wherein the valve body is a molded body of a rubber-like elastic material.   3. The ink jet printer according to claim 2, wherein a portion of the inner periphery of the passage hole facing the outer periphery of the valve body that is far from the communication port is a portion facing a burr generating portion of the valve body.   The said valve body is urged | biased by the said communicating port side, The cyclic | annular protrusion part surrounding the circumference | surroundings of a communicating port is provided in the surface facing the communicating port in a valve body. An inkjet printer according to any one of the above.   5. The ink jet printer according to claim 1, wherein the valve body is displaced so as to be separated from the communication port by an insert inserted from the outside into the communication port. 6.

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