JP2007245444A - Inkjet printer - Google Patents

Abstract

When a space for storing air separated from ink is divided into two, the air is positively flowed into one space and the amount of air stored in the one space is controlled. make it easier.
Ink that has flowed out from one ink outlet 41c is guided to two ink lead-out paths 51Ya and 51b through an ink guide path 48Y, and is supplied to the recording head from both ink lead-out paths. On the lower surface of the ceiling surface of the ink guide passage portion 48Y, a protruding rib 49 is formed on the ink outlet path 51Ya side so as to hang down the air flow toward the ink outlet path 51Ya. A gap that allows the ink to flow is provided between the lower end of the protruding rib 49 and the bottom surface of the ink guide passage portion 48Y. In other words, the protruding rib 49 suppresses the flow of air toward the ink outlet path 51Ya, but is positioned at a lower portion with a gap allowing the ink to flow to the ink outlet path.
[Selection] FIG.

Description

  The present invention relates to an ink jet printer.

  As an inkjet printer that performs recording by discharging ink to a recording medium, the recording head includes a plurality of ink storage chambers for storing ink for each color, and a plurality of inks of a recording head through ink supply ports at the bottom of each ink storage chamber A configuration in which ink is supplied to each of the inflow ports is known (see, for example, Patent Document 1).

  In such an ink jet printer, when ink is supplied from the ink storage chamber to the recording head, air contained in the ink is separated and accumulated in the upper space of the ink storage chamber, and air is supplied to the recording head side. It is configured not to flow. The accumulated air is appropriately discharged outside through an air discharge port connected to the upper space of the ink storage chamber.

By the way, as such a recording head, it is conceivable to increase the number of nozzles in order to increase the recording speed and increase the resolution. In the embodiment shown in FIG. 12 of Patent Document 1, two recording heads are juxtaposed, and two ink supply ports for supplying ink to each recording head are provided for each ink storage chamber. In such a case, it may be necessary to separate the two ink supply ports for specific ink due to the layout.
Japanese Patent Laying-Open No. 2005-125635 (FIG. 12)

  When the two ink supply ports for a specific ink are arranged apart from each other, the corresponding ink storage chamber is also branched into two, and the air separated from the ink is at the top of the two branched portions. It accumulates randomly in the space (air trap region), making it difficult to control the amount of air stored in each upper space. For this reason, it becomes difficult to determine the timing for performing the control to discharge the stored air, and if it is set with a short cycle in anticipation of safety, the air must be discharged frequently, and the throughput of the recording operation is reduced. descend.

The present invention controls the amount of air to be stored by mainly guiding the air separated from the ink to one air trap region when the two ink supply units for a specific ink are arranged apart from each other,
It is an object of the present invention to provide an ink jet printer that can easily control the discharge of accumulated air.

  According to the first aspect of the present invention, there is provided a recording head having a plurality of nozzles for ejecting ink droplets, a plurality of ink storage chambers for storing ink for each type, and an ink from each ink storage chamber extending in the vertical direction. An ink outlet path through which ink is supplied to an ink inlet port of the recording head through an ink supply port opening at a lower end portion of the ink outlet path, and an air exhaust opening at the upper end portion of the ink outlet path. In an ink jet printer configured to discharge air contained in ink through an outlet portion, the recording head includes two ink inlet portions spaced apart from each other for specific ink, and the ink lead-out The two ink outlet paths corresponding to the two ink inlet portions for the specific ink in the paths are arranged apart from each other, and the front At least the upper part of the ink lead-out path for the specific ink is communicated with each other through the communication part, and the ink is led out from the ink storage chamber to the two ink lead-out paths with respect to the upper part of the ink lead-out path or the communication part. Air guide means is provided which mainly guides the air separated from the ink to one of the two ink outlet paths and suppresses the flow to the other ink outlet path. To do.

  According to the first aspect of the present invention, when the ink is led out from the ink storage chamber to the two ink lead-out paths with respect to the upper part of the ink lead-out path or the communication part, the air separated from the ink is Air guide means is provided which mainly guides one ink lead-out path to the other ink lead-out path and suppresses the flow to the other ink lead-out path. Air is mainly guided, and the air separated from the specific ink can be mainly stored in the upper space of the one ink outlet path. Therefore, even when the two ink outlet paths for a specific ink are arranged apart from each other, the amount of air stored in the upper space of the ink outlet path for the specific ink can be easily controlled, Control to discharge the accumulated air becomes easy.

  According to a second aspect of the present invention, in the ink jet printer according to the first aspect, the ink lead-out path is arranged substantially in a line along an edge of the recording head in a direction perpendicular to the nozzle row direction, An ink lead-out path for another ink is disposed between two ink lead-out paths for the other ink, and the communication portion is provided to bypass the ink lead-out path for the other ink. To do.

  According to the invention of claim 2, even if an ink lead-out path for another ink is arranged between two ink lead-out paths for a specific ink, the ink lead-out for the other ink is arranged. Since the communication path is provided around the path, the same specific ink is easily led to each ink lead-out path through the communication path.

  According to a third aspect of the present invention, in the ink jet printer according to the first or second aspect, the air guiding means hangs down from an upper part of the ink lead-out path or the communication part, and at the upper part thereof, toward the other ink lead-out path. The protruding rib is located at a lower portion with a gap that allows the ink to flow.

  According to the invention of claim 3, with a simple structure of a protruding rib that hangs down from the upper part of the ink outlet path or from the communicating part, the ink flow is allowed through the gap in the lower part, and the upper part is directed to the other ink outlet path side. The air flow can be suppressed. That is, the air separated from the ink mainly flows into one ink outlet path, but the specific ink guided from the ink storage chamber flows equally to two ink outlet paths that are separated from each other.

  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 ink storage chamber for the specific ink is on the one ink outlet path side or one of the air guiding means. It is characterized by communicating with the communication part on the ink outlet path side.

  According to the fourth aspect of the present invention, the ink storage chamber for the specific ink communicates with the one ink outlet path side with respect to the air guiding means, or with the communication portion on the one ink outlet path side. The air separated from the ink can be positively stored in the upper space of the one ink outlet path.

  A fifth aspect of the present invention is the ink jet printer according to any one of the first to fourth aspects, wherein a plurality of the ink storage chambers are provided in the buffer tank so as to store the inks by type, and the buffer tank includes: The upper tank part and the lower tank part are joined, and the lower tank part is formed with the ink supply port part and the lower part of the ink outlet path communicating therewith, while the upper tank part Is characterized in that the air guide means is formed in addition to the air discharge port portion and the upper portion of the ink lead-out path communicating therewith.

  According to the invention of claim 5, since the upper tank portion and the lower tank portion are joined to the buffer tank, the buffer tank is mainly guided to one of the two ink outlet paths with respect to the upper tank section. However, it is possible to easily form the air guide means for suppressing the flow toward the other ink outlet path.

  According to a sixth aspect of the present invention, in the ink jet printer according to any one of the first to fifth aspects, the air discharge port portion opens only at an upper portion of the one of the two ink outlet paths. A feature is that the air accumulated in the upper space of the ink outlet path is discharged to the outside through the air discharge port.

  According to the sixth aspect of the present invention, it is possible to prevent a predetermined amount or more of air from being present in the upper space of the ink lead-out path serving as the air trapping region, and air is prevented from flowing to the recording head side. .

  In the present invention, as described above, when the ink is led out from the ink storage chamber to the two ink lead-out paths through the communication path part with respect to the upper part or the communication part of the two ink lead-out paths arranged apart from each other, Since air separated from the ink is guided mainly to one of the two ink outlet paths and the flow to the other ink outlet path is suppressed, the air guide means is provided. Air can be mainly guided to one ink outlet path side of the path, and air separated from the ink can be mainly stored in an upper space of the one ink outlet path. Therefore, even when the two ink outlet paths for the specific ink are arranged apart from each other, the amount of air stored in the upper space of the ink outlet path for the specific ink does not exceed a predetermined amount. Thus, it is possible to easily control, and control to discharge the accumulated air can be facilitated.

  Accordingly, when the two ink lead-out paths for the specific ink are arranged apart from each other, it is possible to prevent a predetermined amount or more of air from being present in the upper space serving as the air trapping area, so that the air is recorded on the recording head. It is possible to reduce the probability of occurrence of a malfunction that makes it impossible to record due to being sucked into the recording medium.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view showing the main structure of an ink jet printer according to the present invention in a plan view. In the following description, in FIG. 1, the left end side of the drawing is the left direction, the right end side is the right direction, the lower side of the drawing is the front, and the upper side of the drawing is the rear. Further, the side from which ink is ejected is the lower surface and the downward direction, and the opposite side is the upper surface and the upward direction.

  As shown in FIG. 1, an inkjet printer 1 has two guide shafts 2 and 3 provided in parallel in the front and rear, and a head holder 4 that also serves as a carriage is attached to the guide shafts 2 and 3. ing. The head holder 4 holds a recording head 5 that performs recording on the recording paper P by discharging ink droplets from a nozzle group. The head holder 4 is connected to an endless belt 7 that is rotationally driven by a motor 6, and is configured to reciprocate along the guide shafts 2 and 3 by driving the motor 6.

  In addition, a plurality of ink tanks that store ink according to type are disposed at the center in the left-right direction of the main body of the inkjet printer 1. That is, an ink tank 8B containing black ink, an ink tank 8M containing magenta ink, an ink tank 8Y containing yellow ink, and an ink tank 8C containing cyan ink are arranged. Each of the ink tanks 8B to 8C is connected to the tube joint 10 on the head holder 4 through flexible ink supply tubes 9B, 9M, 9Y, and 9C, and serves as an ink supply source.

(Main structure of the head holder)
Next, the main structure of the head holder 4 will be described. Subscripts M, C, B, and Y indicate that they relate to magenta ink, cyan ink, black ink, and yellow ink, respectively.

  As shown in FIGS. 2 and 3, the head holder 4 is formed in a box shape having an upper surface opened and accommodating the buffer tank 31, and the recording head 5 is held on the lower surface of the bottom wall 4c.

  As shown in FIG. 4, the recording head 5 includes a cavity unit 11 having nozzles 13 to 16 arranged in rows for each ink color, and a piezoelectric actuator (not shown) that generates pressure for selectively ejecting ink from the nozzles. Z)). The cavity unit 11 has two ink inlet portions 21Ma, 21Mb, 21Ya, 21Yb, 21Ba, 21Bb, 21Ca, and 21Cb on the upper surface for each ink color. Two ink inlet portions 21Ma, 21Mb, 21Ba, 21Bb, 21Ca, and 21Cb for magenta ink, black ink, and cyan ink are arranged side by side, but two ink inlet portions 21Ya and 21Yb for yellow ink are arranged. Are spaced apart by sandwiching the ink inlet portions 21Ba and 21Bb between them.

  The upper surfaces of the ink inlet portions 21M to 21C are covered with an ink filtering filter (not shown), and the ink is supplied to the nozzles 13 to 16 of each row through the ink flow paths 11a inside the cavity unit 11. Supply.

(Main configuration of buffer tank 31)
A buffer tank 31 is accommodated in the head holder 4. As shown in FIG. 3, the buffer tank 31 includes an upper tank portion 32 and a lower tank portion 33 that are connected in parallel in the vertical direction. In the front-rear direction, the ink introduction area is sequentially from the front side. S1, buffer area S2, and ink derivation area S3.

  In the buffer area S2, the upper tank portion 32 is adjacent to an intermediate wall portion 34 with an ink storage chamber 41 for storing yellow ink on the upper side and an ink storage chamber 42 for storing magenta ink on the lower side. Each is formed. The lower tank 33 is formed with an ink storage chamber 43 for storing cyan ink on the upper side and an ink storage chamber 44 for storing black ink on the lower side, with the intermediate wall 35 interposed therebetween. ing. The ink storage chambers 41 to 44 are parallel to each other and are stacked in the vertical direction, and are formed separately in two in the upper and lower tank portions 32 and 33.

  Accordingly, the ink storage chambers 41 to 44 are arranged in the buffer tank 31 in order from the top, and the yellow, magenta, cyan, and black inks are stored by type. That is, the ink storage chambers 41 to 44 temporarily store the ink supplied from the ink tanks 8B to 8C to the nozzle groups of the recording head according to type.

  In the ink lead-out area S3, ink lead-out paths 51M, 51Ya, 51B, 51Yb, 51C corresponding to the ink storage chambers 41 to 44 are arranged in the scanning direction of the print head 5 behind the buffer area S2, that is, the print head 5 of the print head 5. The ink inflow ports 21M to 21C are arranged in a line along the arrangement direction.

  The ink outlet paths 51M to 51C are formed to extend in the stacking direction of the ink storage chambers 41 to 44 with substantially the same length. That is, as shown in FIG. 8, the ink outlet paths 51M to 51C are provided in the cylindrical wall portions 40a and 40b formed corresponding to the upper and lower tank portions 32 and 33, respectively, by the partition wall portions 40c and 40d. It is divided and formed. The ink outlet path 51B at the center in the arrangement direction of the ink outlet paths 51M to 51C has two ink supply port portions 39Ba and 39Bb facing the two ink inlet portions 21Ba and 21Bb in the center of the recording head 5 at the lower end. is doing. The ink outlet path 51C at one end in the arrangement direction opens two ink supply ports 39Ca and 39Cb facing the two ink inlet ports 21Ca and 21Cb on the same side of the recording head 5 at the lower end. The ink outlet path 51M at the other end in the arrangement direction has two ink supply ports 39Ma and 39Mb facing the two ink inlet ports 21Ma and 21Mb on the same side of the recording head 5 at the lower end.

  The ink lead-out path 51Yb sandwiched between one end and the central ink lead-out paths 51C and 51B opens one ink supply port 39Yb that faces one ink inlet 21Yb of the recording head 5. The ink lead-out path 51Ya sandwiched between the other end and the central ink lead-out paths 51M and 51B opens one ink supply port 39Ya that opposes one ink inlet 21Ya of the recording head 5. That is, the two ink lead-out paths 51Ya and 51Yb for yellow ink correspond to the ink inlet portions 21Ya and 21Yb of the recording head 5, and the ink lead-out path 51B is sandwiched between them, so that they are separated from each other. Are arranged.

  The upper ends of the two ink outlet paths 51Ya and 51Yb are communicated with each other through an ink guide path 48Y (communication part). The ink guide passage portion 48Y is provided by bypassing the ink outlet passage 51B for black ink on the ink storage chambers 41 to 44 side. An ink outlet 41c of an ink storage chamber 41 described later is opened on the ink guide path 51Ya side of the ink guide path portion 48Y. Further, a protruding rib 49 is formed on the side of the ink outlet path 51Ya close to the ink outlet 41c so as to suspend the air flow to the ink outlet path 51Ya. The lower end of the protruding rib 49 is longer than the lower end of the upper tank portion 32 and has a length that penetrates into the lower tank portion 33, and is between the bottom surface of the ink guide passage portion 48 </ b> Y formed in the lower tank portion 33. In addition, a gap that allows the ink to flow is provided. In other words, the protruding rib 49 suppresses the flow of air to the ink outlet path 51Ya side, but is positioned with a gap allowing the ink flow in the lower part.

  Since each of the ink outlet paths 51M to 51C extends in the vertical direction, the air from the ink that is about to flow into the ink inlet portions 21M to 21C of the recording head 5 from each of the ink storage chambers 41 to 44, as described later, is satisfactorily air. And the air is accumulated in the upper spaces of the ink outlet paths 51M to 51C. That is, the upper space of the ink outlet paths 51M to 51C functions as an air trap region where the separated air contained in the ink is accumulated.

  The air accumulated in the upper spaces of the ink outlet paths 51M to 51C in this way is discharged into the exhaust passage 71M through the air discharge ports 46M, 46Ya, 46B, 46Yb, 46C formed at the upper ends of the ink outlet paths 51M to 51C. To 71B.

  The cylindrical wall portions 40a and 40b and the partition wall portions 40c and 40d that form the ink lead-out paths 51M to 51C are divided into upper and lower portions corresponding to the upper and lower tank portions 32 and 33, respectively. That is, the lower tank portion 33 is provided with a cylindrical wall portion 40b and a partition wall portion 40d that internally form ink outlet paths 51M to 51C on one side of the ink storage chambers 41 to 44. On the other hand, in the upper tank portion 32, the cylindrical wall portion 40a and the partition wall portion 40c which are extended portions that overlap the upper ends of the cylindrical wall portion 40b and the partition wall portion 40d and form the upper end portions of the ink outlet paths 51M to 51C. Is provided. In the tubular portion 40a, the upper ends of the ink outlet paths 51M to 51C are opened to the exhaust passages 71M to 71B as air discharge port portions 46M to 46B for discharging the air contained in the ink.

  By aligning the cylindrical wall portions 40a and 40b and the partition wall portions 40c and 40d of the tank portions 32 and 33 and joining them using joining means such as ultrasonic welding and adhesion, the ink lead-out paths 51M to 51M The upper side portion and the lower side portion of 51C are joined, and the ink outlet paths 51M to 51C are continuously formed across the upper and lower tank portions 32 and 33. At the same time, the upper and lower tank portions 32 and 33 are combined and integrated with each other. In this state, the ink storage chambers 41 to 44 are formed in a stacked state as described above.

  The ink introduction area S1 includes an extension 40e extending forward from the buffer area S2. As shown in FIG. 3, the extension 40 e is overlapped and supported on a mounting arm 4 a that extends forward and horizontally from the front end of the head holder 4. A tube joint 10 is attached to the upper surface in front of the extension 40e. Ink supply tubes 9B to 9C are connected to the tube joint 10, and the ink supply tubes 9B to 9C communicate with the ink flow path openings 52B to 52C opened on the upper surface of the extension portion 40e in a one-to-one correspondence. Yes.

  As shown in FIG. 7, ink flow paths 53B, 53M, 53Y, and 53C having upstream ends connected to the ink flow path openings 52B to 52C are formed on the lower surface of the extension 40e. Each of the ink flow paths 53B to 53C is formed as a concave groove extending in the front-rear direction, and is arranged side by side in the left-right direction on the lower surface of the extension 40e.

  Each opening surface in the longitudinal direction of the lower surface of the ink flow paths 53B to 53C is sealed with a film 54 (see FIG. 3). The film 54 serves as the bottom surface of each of the ink flow paths 53B to 53C, and the ink flow paths 53B to 53C are formed by the inner surface (upper surface and left and right side surfaces) of the concave groove and the film 54.

  The extension portion 40e is integrally formed so as to be connected to the intermediate wall portion 34 (see FIG. 3) of the upper tank portion 32, and the rear ends of the ink flow paths 53B to 53C are extended as shown in FIG. The ink channels 56B, 56M, 56Y, and 56C formed on the upper surface of the extended portion 40e are connected through ink introduction holes 55B, 55M, 55Y, and 55C that vertically penetrate the portion 40e.

  The left and right ink flow paths 56C and 56B are connected to the ink storage chambers 44 and 43 of the lower tank portion 33 through the ink communication paths 58C and 58B, as will be described later, and are connected to the two central ink flow paths 56Y and 56Y. 56M is connected to the ink storage chambers 41 and 42 of the upper tank portion 32, respectively.

  Cylindrical wall portions 57a and 57b project from the opposing surfaces of the upper and lower tank portions 32 and 33 at positions overlapping the rear ends of the left and right ink flow paths 56C and 56B in plan view. The upper ends of the ink communication paths 58C and 58B penetrating 57a and 57b are connected to the rear ends of the ink flow paths 56C and 56B. The cylindrical wall portions 57a and 57b are disposed along the front edge side of the ink storage chambers 41 to 44 and spaced from each other in the vicinity of both ends in the left-right direction of the ink storage chambers, and at the left and right ends of the ink outlet paths 51M to 51C. The ink lead-out paths 51M and 51C are arranged so as to correspond in the front-rear direction.

  The cylindrical wall portions 57a and 57b are formed by joining the protruding portions 57aa and 57ab on the upper tank portion 32 side and the protruding portions 57ba and 57bb on the lower tank portion 33 side to each other. Therefore, the protruding portions 57aa, 57ab, 57ba, 57bb of the cylindrical wall portions 57a, 57b are joined to each other in the front-rear direction by a joining means such as ultrasonic welding or adhesion, so that the ink flow in the upper tank portion 32 is achieved. The paths 56C, 56B and the ink storage chambers 43, 44 of the lower tank portion 33 are connected via ink communication paths 58C, 58B. The cylindrical wall portions 57a and 57b may be formed so as to protrude from only one of the upper tank portion 32 and the lower tank portion 33.

  Further, by joining the projecting portions 57aa, 57ab, 57ba, 57bb of both the cylindrical wall portions 57a, 57b at the same time, the above-described cylindrical wall portions 40a, 40b are also joined, whereby the upper and lower tank portions 32, 33 are mutually connected. Connected and integrated.

  In the vicinity of the cylindrical wall portions 57 a and 57 b, the engaging portion 32 a that is formed to protrude from the upper tank portion 32 is connected to the engaged portion 33 a that is formed to protrude to the lower tank portion 33, and the lower tank portion 33. The upper tank portion 32 is in contact with and engaged in a direction that restricts the relative rotation of the upper tank portion 32 with respect to the front side. Thereby, even when the width in the left-right direction of the upper and lower tank portions 32, 33 is wide, the two can be stably joined.

(Main structures of the ink storage chambers 41 to 44)
Next, the main structure of each of the ink storage chambers 41 to 44 will be described with reference to the drawings.

-Structure of ink storage chamber 41 for yellow ink-
The ink storage chamber 41 will be described with reference to FIGS.

  In the buffer area S2, a surrounding wall portion 41a having a substantially rectangular shape in plan view is provided on the upper surface around the intermediate wall portion 34 of the upper tank portion 32, and the upper opening of the internal space surrounded by the surrounding wall portion 41a is deformed. An ink storage chamber 41 for yellow ink, which is a flat space, is formed by being closed by a film 61 that is a flexible film. The flexibility of the film 61 means flexibility that can be bent by a pressure change generated in the ink in the ink storage chamber 41.

  In the ink storage chamber 41, the downstream end of the ink flow path 56 </ b> Y opens as an ink inlet 41 b in the vicinity of the substantially central portion of the front portion of the rotating wall portion 41 a so that ink from the ink tank 8 </ b> Y flows. Yes. In addition, the rear portion of the circumferential wall portion 41a is located slightly to the left from the center in the left-right direction and is displaced to the right from the rear left corner of the ink storage chamber 41, and the rear side of the circumferential wall portion 41a. An ink outlet 41c through which the yellow ink in the ink storage chamber 41 flows out is formed at a location slightly protruding backward from the portion, and the ink flows out to the nozzles of the recording head 5.

  The ink inlet 41 b and the ink outlet 41 c for yellow ink are provided at substantially diagonal positions in the ink storage chamber 41. In other words, the ink storage chambers 41 are formed at positions that are most distant from each other across most of the space in the ink storage chamber 41.

  Therefore, the ink storage chamber 41 includes a pair of wall surfaces (the upper surface of the intermediate wall portion 34 and the lower surface of the film 61) that are parallel to and opposed to the ink flow direction from the ink inlet 41b to the ink outlet 41c, and a space between the pair of wall surfaces. And a surrounding wall portion 41a surrounding the space.

  The ink outlet 41c extends downward from the bottom surface of the ink storage chamber 41 through the intermediate wall portion 34 of the upper tank portion 32 and opens above the ink guide passage portion 48Y serving as a communication portion, and passes through the ink guide passage portion 48Y. The two ink outlet paths 51Ya and 51Yb are connected to each other, and the ink outlet paths 51Ya and 51Yb are connected to the ink inlet portions 21Ya and 21Yb of the recording head 5. That is, the ink outlet path 51B for the black ink is disposed between the two ink outlet paths 51Ya and 51Yb corresponding to the two ink inlet portions 21Ya and 21Yb for the yellow ink. Therefore, the upper part of the ink outlet paths 51Ya and 51Yb for the yellow ink are communicated with each other through the ink guide path portion 48Y, bypassing the ink outlet path 51B for the black ink.

  The ink guide passage portion 48Y communicates the upper portions of the ink outlet passages 51Ya and 51Yb for yellow ink with each other. However, it is sufficient that at least the upper portions communicate with each other, and the intermediate portion connected to the upper portion also communicates with each other. It is also possible to adopt a configuration that allows communication.

  The film 61 seals not only the upper opening of the circumferential wall portion 41a but also the portions opened above the ink flow paths 56M to 56Y, the connection lead-out path 65M, the ink path section 70B, and the exhaust paths 71M to 71B described later. It has stopped. That is, the upper surfaces of the side walls that define the outer peripheries of the ink flow paths 56M to 56Y, the connection outlet path 65M, the ink passage portion 70B, and the exhaust passages 71M to 71B are on the same plane as the upper surface of the circumferential wall portion 41a around the ink storage chamber 41. The film 61 is bonded to the upper surface thereof by bonding means such as adhesion or heat welding. Thereby, the ink storage chamber 41, the ink flow paths 56M to 56Y, the connection outlet path 65M, the ink passage portion 70B, and the exhaust passages 71M to 71B are partitioned.

  Further, the flat bottom surface (upper surface of the intermediate wall portion 34) of the ink storage chamber 41 protrudes toward the film 61 with a gap on both sides of the line connecting the ink inlet 41b and the ink outlet 41c of the yellow ink, and the film. A pair of rectifying ribs 41d and 41e extending in parallel with the ink flow direction with a space from 61 are formed to be integral with each other. Further, the pair of rectifying ribs 41d and 41e are located outside the both rectifying ribs 41d and 41e in the opposing direction of each other with a circumferential wall portion 41a and a triangular space in plan view. The ends of the pair of rectifying ribs 41d and 41e in the ink flow direction are spaced from the inner wall surface of the circumferential wall portion 41a in the extending direction by intervals 41da, 41db, 41ea, and 41eb. As a result, the space between the pair of rectifying ribs 41d and 41e (the space serving as the ink flow path) and the space between the outer peripheral wall portion 41a are connected through the intervals 41da, 41db, 41ea, and 41eb. . The intervals 41da, 41db, 41ea, 41eb are set to a length of about 1 to 2 mm.

  The pair of straightening ribs 41d and 41e are for guiding the rapid flow of ink from the ink inlet 41b to the ink outlet 41c. In addition, a guide rib 41f made of a small piece having a bent portion guides the flow of ink toward the ink outlet 41c along the bent rectifying rib 41d between the rectifying rib 41d and the rectifying rib 41e. It is formed as follows.

  The straightening ribs 41d and 41e and the guide rib 41f each have a rectangular cross section, and are both formed to have a height about half the depth of the ink storage chamber 41 (distance from the film 61 to the bottom surface). 61 is provided so as not to limit the movement of the film 61.

-Ink storage chamber 42 for magenta ink-
The ink storage chamber 42 will be described with reference to FIGS. 7 is a view of the upper tank portion 32 as viewed from below, the left direction in the figure is the “right direction” and the right direction in the figure is the “left direction”.

  On the lower surface of the intermediate wall portion 34 of the upper tank portion 32, an ink storage chamber 42 for magenta ink is formed which is a flat space having a substantially square shape in plan view and the lower surface opening in the same shape. The ink storage chamber 42 is partitioned by a circumferential wall 42a, and is provided on the lower side adjacent to the ink storage chamber 41 via the intermediate wall 34 as shown in FIGS. .

  The ink inlet 42b of the ink storage chamber 42 for magenta ink has a round hole shape, and is opened on the bottom surface near the right front corner in the ink storage chamber 42. The ink flow path 56M penetrates the upper tank portion 32. It is connected to the downstream end (see FIG. 6).

  The ink outlet 42c of the ink storage chamber 42 has a rectangular hole shape, and is opened at the bottom surface near the left rear corner that is diagonal to the ink inlet 42b and penetrates the upper tank portion 32. On the upper surface of the upper tank portion 32, a connection outlet path 65M is formed at a position corresponding to the ink outlet 42c and outside the ink storage chamber 41. One end of the connection lead-out path 65M is connected to the ink outlet 42c penetrating the upper tank portion 32, and the other end is connected to the ink lead-out path 51M through an opening 65Ma penetrating the upper tank portion 32 from the upper surface to the lower surface. Two ink supply ports 39Ma and 39Mb are provided at the bottom of the ink outlet path 51M.

  The ink inlet 42 b and the ink outlet 42 c for magenta ink are provided at substantially diagonal positions in the ink storage chamber 42. In other words, the ink storage chambers 42 are formed at positions that are almost farthest apart from each other across most of the space in the ink storage chamber 42. That is, the ink inlet 42b and the ink outlet 42c for magenta ink are formed at positions that are almost farthest from each other across a large space in the ink storage chamber 42 through which the ink flows.

  The yellow ink storage chamber 41 and the magenta ink storage chamber 42 are vertically adjacent to each other with the intermediate wall portion 34 of the upper tank portion 32 interposed therebetween, and the yellow ink ink inlet 41b and the ink outlet 41c. The magenta ink inlet 42b and the ink outlet 42c are arranged at different positions along the intermediate wall 34. That is, when the upper tank portion 32 is viewed in plan, the line connecting the ink inlet 41b and the ink outlet 41c for yellow ink and the line connecting the ink inlet 42b and the ink outlet 42c for magenta ink extend in different directions, and It intersects like a diagonal line.

  The surface opened below the ink storage chamber 42 is sealed with a flexible film 62. The film 62 is bonded onto the circumferential wall portion 42a of the ink storage chamber 42 by a bonding means such as adhesion or heat welding, so that the ink storage chamber 42 is partitioned.

  On the bottom surface of the ink storage chamber 42, rectifying ribs 42d and 42e are provided upright. The rectifying ribs 42d and 42e are provided in parallel so that the distance from the diagonal line is substantially equal across the diagonal line connecting the ink inlet 42b and the ink outlet 42c of magenta ink. The straightening ribs 42d and 42e each have a quadrangular vertical cross section, and both are formed at a height about half the depth of the ink storage chamber 42 (distance from the film 62 to the bottom surface). However, the movement of the film 62 is not limited. The rectifying ribs 42d and 42e are for guiding the rapid flow of ink from the ink inlet 42b to the ink outlet 42c. The end portions of the flow regulating ribs 42d and 42e in the ink flow direction are also spaced from the inner wall surface of the circumferential wall portion 42a in the extending direction by intervals 42da, 42db, 42ea and 42eb.

-Ink storage chamber 43 for cyan ink-
The ink storage chamber 43 will be described with reference to FIGS.

  On the upper side of the intermediate wall portion 35 of the lower tank portion 33, a cyan ink storage chamber 43 having the same shape at a position corresponding to the magenta ink storage chamber 42 is partitioned by the circumferential wall portion 43 a, and upward. It is open. On the bottom surface of the ink storage chamber 43, rectifying ribs 43d and 43e having the same shape as the rectifying ribs 42d and 42e (see FIG. 7) are provided. The end portions of the flow regulating ribs 43d and 43e in the ink flow direction are also spaced from the inner wall surface of the circumferential wall portion 43a in the extending direction by intervals 43da, 43db, 43ea, and 43eb.

  Similar to the ink storage chamber 42 for magenta ink, the opening surface of the cyan ink storage chamber 43 is sealed with a substantially rectangular flexible film 63. As a result, the film 62 of the magenta ink storage chamber 42 and the film 63 of the cyan ink storage chamber 43 face each other in parallel.

  The ink inlet 43b for the cyan ink is opened at the bottom surface near the left front corner in the ink storage chamber 43, passes through the intermediate wall 35 of the lower tank 33 in the thickness direction, and passes through the intermediate wall portion. 35 is connected to one end of a communication path 66 formed on the lower surface of 35. The communication path 66 is formed outside the black ink storage chamber 44 at the left front corner, and the other end is connected to the lower end of the ink communication path 58C penetrating the lower tank section 33 in the thickness direction. Has been.

  That is, the ink flow path 56C formed on the upper surface of the intermediate wall portion 34 of the upper tank portion 32 is cyan via the ink communication path 58C and the communication passage 66 that penetrate the upper and lower tank portions 32 and 33 in the stacking direction. The ink reservoir 43 communicates with an ink inlet 43 b of cyan ink.

  The ink outlet 43c of the ink storage chamber 43 is opened at the bottom surface in the vicinity of the right rear corner in the ink storage chamber 43, and passes through the intermediate wall 35 of the lower tank portion 33 in the thickness direction. A connection lead-out path 65 </ b> C formed on the lower surface of the tank portion 33 is connected. As shown in FIG. 9, the connection lead-out path 65 </ b> C is formed in a rectangular cross section at the corner on the right rear side outside the ink storage chamber 44 for black ink. The downstream end portion of the connection lead-out path 65C is positioned so as to overlap with the ink lead-out path 51C in plan view, and is lower than the upper end of the ink lead-out path 51C through an opening 65Ca that passes through the lower tank portion 33 from below to above. (See FIG. 12).

-Black ink ink storage chamber 44-
The ink storage chamber 44 will be described with reference to FIGS. 9 and 13. Since FIG. 9 is a view seen from below, the upward direction in the figure is “front direction” and the downward direction in the figure is “rear direction”.

  On the lower surface of the intermediate wall portion 35 of the lower tank portion 33, there is formed an ink storage chamber 44 for black ink that is a flat space having a substantially square shape in plan view and having the lower surface opened in the same shape. The ink storage chamber 44 is partitioned by a circumferential wall portion 44a, and is provided adjacent to the ink storage chamber 43 for cyan ink in the vertical direction via the intermediate wall portion 35 as shown in FIGS. It has been.

  Further, a communication path 66 for cyan ink is provided adjacent to the left front corner of the ink storage chamber 44, and a connection outlet path 65C is provided adjacent to the right rear corner.

  The front portion of the ink storage chamber 44 is positioned so as to overlap with the ink communication path 58 </ b> B in a plan view, and the ink communication path 58 </ b> B penetrates the lower tank portion 33 in the vertical direction, and the right front in the ink storage chamber 44. It opens to the bottom surface near the corner. That is, the lower end opening of the ink communication path 58 </ b> B serves as the ink inlet 44 b of the ink storage chamber 44.

  An ink outlet 44 c for black ink that allows the black ink in the ink storage chamber 44 to flow out is opened on the bottom surface in the vicinity of the left rear corner in the ink storage chamber 44. The ink outlet 44c is a lower end of a through passage 69B that penetrates the upper and lower tank portions 32 and 33 in the vertical direction. The upper end of the through passage 69B is ink on the upper surface side of the intermediate wall portion 34 of the upper tank portion 32. It opens to one end of the passage portion 70B, and is connected to the upper portion of the ink outlet passage 51B from the other end opening 70Ba of the ink passage portion 70B passing through the upper tank portion 32 in the vertical direction through the ink passage portion 70B.

  The black ink inlet 44 b and the ink outlet 44 c are provided at substantially diagonal positions in the ink storage chamber 44. In other words, the ink storage chambers 44 are formed at positions that are most distant from each other across most of the space in the ink storage chamber 44.

  The ink storage chamber 44 and the ink storage chamber 43 are vertically adjacent to each other via the intermediate wall portion 35 of the lower tank portion 33. The ink inlet 44b and the ink outlet 44c for black ink, and the cyan ink The ink inlet 43 b and the ink outlet 43 c are arranged at different positions along the intermediate wall portion 35.

  That is, when the lower tank 33 is viewed in plan, the line connecting the cyan ink inlet 43b and the ink outlet 43c and the line connecting the black ink inlet 44b and the ink outlet 44c extend in different directions, They cross each other like a diagonal line.

  The surfaces of the black ink ink storage chamber 44, the communication path 66, and the connection lead-out path 65 </ b> C that are open below are sealed with a flexible film 64. The lower surface of the circumferential wall portion 44a that defines the communication passage 66, the connection outlet passage 65C, and the ink storage chamber 44 is formed on the same plane, and the film 64 is bonded to the surface by bonding means such as adhesion or heat welding. . Thereby, the ink storage chamber 44 for black ink, the communication path 66, and the connection outlet path 65C are partitioned.

  On the bottom surface of the ink storage chamber 44, rectifying ribs 44d and 44e are provided upright on both sides of a line connecting the ink inlet 41b and the ink outlet 41c. The rectifying ribs 44d and 44e each have a rectangular cross section, and both are formed at a height that is about half the depth of the ink storage chamber 44 (distance from the film 64 to the bottom surface). The film 64 is positioned so as not to limit the movement. The rectifying ribs 44d and 44e are for guiding the rapid flow of ink from the ink inlet 44b to the ink outlet 44c, and their end portions are connected to the inner wall surface of the circumferential wall portion 44a.

  As shown in FIGS. 3 and 9, the buffer tank 31 is fixed to the recording head 5 fixed to the lower surface of the bottom wall 4 c of the head holder 4 with three screws 23. Specifically, through holes 24a, 24b, and 24c are provided on both outer sides and intermediate sides of the ink supply ports 39M to 39C arranged in a row, and a screw 23 is inserted into each of the through holes 24a to 24c. Has been. A seal rubber material (not shown) is sandwiched between the ink supply ports 39M to 39C and the ink inflow ports 21M to 21C, and the buffer tank 31 is fixed to the recording head 5 with screws 23. Around the ink supply port portions 39M to 39C, there is provided a fall prevention rib 25 of the seal rubber material along the outer periphery of the seal rubber material, and a central through hole portion 24c is provided continuously to a part of the rib 25. The through holes 24a and 24b at both ends are provided by being shifted by about 1 to 2 mm in the opposite directions from the horizontal load center axis L2 of the seal rubber material.

(How each ink flows)
As shown in FIGS. 6 and 7, the yellow ink is introduced into the ink storage chamber 41 from the ink inlet 41b through the ink flow path opening 52Y, the ink flow paths 53Y and 56Y. The yellow ink introduced into the ink storage chamber 41 flows across most of the space in the ink storage chamber 41 from the ink inlet 41b toward the ink outlet 41c.

  As shown in FIG. 10, the yellow ink that has flowed out from the ink outlet 41c of the ink storage chamber 41 passes through the ink guide path portion 48Y that is provided around the ink lead-out path 51B, and is arranged away from each other. 51Ya and 51Yb are supplied to the ink inlet ports 21Ya and 21Yb of the recording head 5 from the ink supply ports 39Ya and 39Yb.

  In this case, as shown in FIGS. 15A and 15B, after being led out from the ink outlet 41c to the ink guide passage 48Y, the air contained in the ink and separated is moved upward, and the ink lead-out path 51Ya. Since the protruding rib 49 provided on the side suppresses the flow to the ink outlet path 51Ya side, as a result, it is mainly guided to the ink outlet path 51Yb side. That is, the protruding rib 49 functions as a baffle plate that suppresses the flow of air toward the ink outlet path 51Ya. Therefore, the air contained in the yellow ink and separated can be mainly stored in the upper space of one ink outlet path 51Yb without flowing randomly in the upper spaces of the two ink outlet paths 51Ya and 51Yb. Therefore, even when the two ink outlet paths 51Ya and 51Yb for yellow ink are arranged apart from each other, the ink outlet path can be mainly stored in the upper space of one ink outlet path 51Yb. As in the case where there is only one, the amount of air stored in the upper space of the ink outlet path 51Yb can be easily controlled.

  On the other hand, since a gap is provided between the lower end of the protruding rib 49 and the bottom surface of the ink guide passage portion 48Y, the ink flow is ensured through the gap. Therefore, the protruding rib 49 secures the ink flow to both the ink outlet paths 51Ya and 51Yb and suppresses the air flow to the ink outlet path 51Ya side.

  As shown in FIGS. 6 and 7, the magenta ink is introduced from the ink flow path opening 52M through the ink flow paths 53M and 56M into the ink storage chamber 42 below the upper tank portion 32 from the ink inlet 42b. The magenta ink introduced into the ink storage chamber 42 flows from the ink inlet 42b toward the ink outlet 42c.

  As shown in FIG. 11, the magenta ink that has flowed out of the ink outlet 42c of the ink storage chamber 42 reaches the ink outlet path 51M through the connection outlet path 65M, and the ink flow of the recording head 5 from the ink supply ports 39Ma and 39Mb. It is supplied to the inlet portions 21Ma and 21Mb.

  As shown in FIGS. 6, 7 and 8, the cyan ink passes through the ink flow path opening 52C, the ink flow paths 53C and 56C, and the ink communication path 58C penetrating the upper and lower tank portions 32 and 33 in the stacking direction. Then, after flowing into the communication path 66 on the lower surface side of the lower tank portion 33, it is introduced into the ink storage chamber 43 on the upper surface side from the ink inlet 43b. The cyan ink introduced into the ink storage chamber 43 flows from the ink inlet 43b toward the ink outlet 43c.

  As shown in FIG. 12, the ink that has flowed out from the ink outlet 43c of the ink storage chamber 43 reaches the ink outlet path 51C through the connection outlet path 65C, and is supplied from the ink supply ports 39Ca and 39Cb to the ink inlet section of the recording head 5. Supplied to 21Ca and 21Cb.

  As shown in FIGS. 6, 7, and 9, the black ink passes through the ink flow path opening 52 </ b> B, the ink flow paths 53 </ b> B and 56 </ b> B, and the ink communication path 58 </ b> B that penetrates the upper and lower tank portions 32 and 33 in the stacking direction. Then, the ink is introduced into the ink storage chamber 44 on the lower surface side of the lower tank portion 33 from the ink inlet 44b (lower end opening of the ink communication passage 58B). The black ink introduced into the ink storage chamber 44 flows from the ink inlet 44b toward the ink outlet 44c.

  As shown in FIG. 13, the black ink that has flowed out of the ink storage chamber 44 once rises to the upper surface side of the intermediate wall portion 34 of the upper tank portion 32 through the through passage 69B, and passes through the ink passage portion 70B to the ink outlet passage 51B. The ink supply ports 39Ba and 39Bb are supplied to the ink inlet ports 21Ba and 21Bb of the recording head 5.

  In this way, each of the ink that has flowed out of the ink storage chambers 41 to 44 flows into and is stored in the ink outlet paths 51M to 51C that extend in the vertical direction, so that air is well separated from the ink in the ink outlet paths 51M to 51C. The air trapped by the filters provided at the ink inlet portions 21M to 21C of the recording head 5 is floated to accumulate the air in the upper spaces of the ink outlet passages 51M to 51C, and exhausted through the air outlet ports 46M to 46B. It can discharge | emit to channel | path 71M-71B.

  Each ink is supplied to the ink inlets 21M to 21C of the recording head 5 described above while scanning the ink storage chambers 41 to 44 and the recording head 5 with respect to the recording medium. Although easily affected, one of the upper and lower wall surfaces of the ink storage chambers 41 to 44 is a film 61 to 64 that is a flexible film, so that variation in ink pressure or the like is effectively suppressed by deformation of the films 61 to 64. High quality recording. In particular, since the films 61 to 64 are provided as parallel walls defining the ink storage chambers 41 to 44, the area of the film can be increased while suppressing the height in the laminating direction, and fluctuations in ink pressure and the like can be achieved. It is advantageous in suppressing.

(Structure of exhaust passages 71M to 71B)
The upper ends of the ink outlet passages 51M to 51C located above the ink supply ports 39M to 39C are air discharge ports 46M to 46C formed on the upper surface of the upper tank portion 32 as shown in FIGS. Connected to the upper tank portion 32 and disposed on one side of the buffer area S2 through exhaust passages 71M, 71Y, 71B, 71C formed as concave grooves along the upper surface of the upper tank portion 32. The exhaust devices are connected to the upper ends of the exhaust devices (only the exhaust device 45B for black ink is shown, see FIG. 14). Each exhaust device is disposed such that the axial direction of its exhaust valve is parallel to the longitudinal direction of the ink outlet paths 51M to 51C. In this manner, the air discharge ports 46M to 46C positioned at the upper ends of the ink outlet paths 51M to 51C and the upper end of the exhaust device are connected to each other by the exhaust passages 71M to 71C formed on the upper surface of the upper tank portion 32. . The exhaust passages 71 </ b> M to 71 </ b> C are defined by extending and covering the open upper surfaces of the flexible films 61 that serve as the upper surfaces of the ink storage chambers 41.

  As shown in FIG. 6, each of the exhaust passages 71 </ b> M to 71 </ b> C temporarily extends rightward from the upper ends of the ink outlet paths 51 </ b> M to 51 </ b> C along the side edge portion of the yellow ink storage chamber 41 on the upper surface of the upper tank portion 32. To the upper end of each exhaust system.

  By driving and controlling the exhaust device to appropriately open the exhaust valve, the air accumulated in the upper spaces of the ink outlet paths 51M to 51C is exhausted to the outside through the exhaust paths 71M to 71C.

(Schematic structure of exhaust system)
A plurality of exhaust devices are provided corresponding to the number of ink lead-out paths 51M to 51C, and they are arranged from the ink lead-out area S3 through the buffer area S2 toward the ink introduction area S1, and the cylindrical walls 40a, 40b, The ink storage chambers 41 to 44 and the cylindrical wall portions 57a and 57b are arranged in a row substantially in parallel with the row.

  The exhaust device is provided to extend from the upper and lower tank portions 32 and 33 via the arm portions 81 (81A and 81B), respectively, and the ink outlet paths 51M to 51C of the ink storage chambers 41 to 44 are provided in a row. It is arranged on the right side different from the rear side.

  The lower portion 82B of the exhaust valve box 82 of the exhaust device includes a cylindrical wall portion 45b extending in the vertical direction, and is coupled to the lower tank portion 33 via the lower portion 81B of the arm portion 81. .

  On the other hand, the upper portion 82A of the exhaust valve box 82 includes a cylindrical wall portion 45a that overlaps with the upper end of the cylindrical wall portion 45a in the upper tank portion 32, and is coupled to the upper tank portion via the upper portion 81A of the arm portion 81. Has been. An intermediate portion of the exhaust passages 71M to 71B is provided on the upper surface side of the upper portion 81A of the arm portion 81. The downstream end portions of the exhaust passages 71M to 71B extend on the cylindrical wall portion 45a and communicate with the internal space of the cylindrical wall portion 45b through the internal space of the cylindrical wall portion 45a.

  That is, the upper tank portion 32 integrally includes the upper portion 82A of the exhaust valve box 82 including the cylindrical wall portion 45a, and the lower tank portion 33 includes the lower portion 82B of the exhaust valve box 82 including the cylindrical wall portion 45b. When the upper and lower tank portions 32 and 33 are joined together as described above, the cylindrical wall portions 45a and 45b are also joined at the same time to form the exhaust valve box 82.

  In the lower portion 82B of the exhaust valve box 82, engaging portions 33b are formed at both ends of the exhaust device in the arrangement direction, while in the upper portion 82A, the engaged portions are removably engaged with the engaging portions 33b. A stop hole portion 32b is formed. With these engaged, the cylindrical wall portions 45a and 45b are joined to each other. In this way, the coil springs of each exhaust device (for example, the coil springs for the black ink exhaust device) are placed on a line L1 (see FIG. 6) connecting the engaging portions of the engaging portion 33b and the engaging hole portion 32b. 103, see FIG. 14), the upper portion 82A is not tilted by the spring force of the coil spring when the upper and lower portions 82A and 82B are locked, and at the time of joining by ultrasonic welding or the like, It is possible to avoid a joining deviation between the upper part 82A and the lower part 82B.

  An exhaust device is provided for each of the exhaust passages 71M to 71B, but all have the same configuration, and therefore, only the exhaust portion for black ink will be described below with reference to FIG.

  As shown in FIG. 14, the exhaust hole 101 communicating with the exhaust passage 71B is long in the vertical direction and opens up and down, and has an exhaust inlet portion 101a and an exhaust outlet portion 101b, and the exhaust valve 102 is slidable. It functions as a valve chamber. The exhaust hole 101 has an upper large-diameter hole portion 101A and a small-diameter hole portion 101B located on the lower side, and they communicate with each other through the exhaust outlet portion 101b.

  The exhaust valve 102 includes a large-diameter valve portion 102a, a small-diameter valve rod 102b integrally connected to a lower end thereof, and a ring-shaped sealing material 104 fitted to the valve rod 102b. The valve portion 102a has a larger diameter than the valve rod 102b, and is provided on the valve rod 102b so that the sealing material 104 contacts the valve portion 102a. Further, the valve portion 102a faces the opening end surface 101C (valve seat surface) around the exhaust outlet portion 101b which is the bottom surface of the large-diameter hole portion 101A and the upper-end opening portion of the small-diameter hole portion 101B through the sealing material 104. To do. A large-diameter valve portion 102A is inserted into the large-diameter hole portion 101A of the exhaust hole 101, and a valve rod 102b is inserted into the small-diameter hole portion 101B with a gap that allows air (gas) to flow therethrough. Thus, the exhaust valve 102 is slidably supported in the exhaust hole 101 (valve chamber) in the central axis direction. Since the valve rod 102b is pushed up by the protruding shaft 121 provided in the maintenance unit when the valve is opened as will be described later, the lower end thereof is located in the vicinity of the lower end opening of the small-diameter hole 101B (when the valve is closed). It is like that.

  An opening end surface 101C around the exhaust outlet portion 101b communicating with the atmosphere serves as a valve seat surface, and the sealing material 104 is disposed between the opening end surface 101C and the valve portion 102a.

  In addition, a coil spring 103 is inserted into the large-diameter hole portion 101A as urging means for urging the exhaust valve 102 (valve portion 102a) in a direction to close the exhaust outlet portion 101b. That is, the upper end portion of the coil spring 103 is fitted to the outside of the engaging convex portion 82Aa of the upper portion 82A of the exhaust valve box 82, and the lower end portion is fitted into the upper concave portion of the valve portion 102a. An exhaust inlet portion 101a is formed around the engaging projection 82Aa, and an exhaust (air) flow path from the exhaust inlet portion 101a to the exhaust outlet portion 101b is formed outside the coil spring 103. .

  As described above, since the valve portion 102a is constantly urged by the coil spring 103 in the direction in which the sealing material 104 abuts against the opening end surface 101C, the pushing-up force by the protruding shaft portion 121 does not act on the exhaust valve 102 at normal times. The valve portion 102a of the exhaust valve 102 is in a valve closed state that closes the exhaust outlet portion 101b.

  A plurality of groove portions 102d are formed in the valve rod 102b of the exhaust valve 102 over the entire length. A groove 102d formed in the valve rod 102b is a gap (exhaust flow path) that reliably allows air to flow between the valve rod 102b and the seal material 104 when the valve portion 102a and the seal material 104 are separated. ).

  Further, as a part of a maintenance unit that performs cleaning of the nozzle surface of the recording head 5, recovery processing for selectively sucking ink for each color, and removal processing for removing air retained in the buffer tank 31, And a plurality of cap members 123 that individually cover the lower end surface of the exhaust valve box 82 (that is, the lower end opening surface of each small-diameter hole portion 101b) so as to be opened and closed. The cap member 123 is supported so as to be movable up and down by a vertical movement mechanism similar to a known maintenance unit. When the recording head 5 moves to a standby position where recording is not performed, the cap member 123 moves to a raised position that is in close contact with the lower end surface of the exhaust valve box 82, and descends away from those surfaces at other positions. Move to position.

  Each cap member 123 has a protruding shaft portion 121 that protrudes from the cap member 123. When the cap member 123 comes into close contact with the lower end surface of the exhaust valve box 82, the protruding shaft portion 121 attaches the exhaust valve 102 to the coil spring 103. Pushing up against the force, the sealing material 104 is separated from the opening end face 101C of the large-diameter hole 101A, and the valve is in an open state in which the exhaust outlet 101b is opened.

  The cap member 123 is connected to a suction pump (not shown) via the exhaust passage 122, and the air accumulated in the upper space of each ink outlet passage 51B is sucked and discharged to the atmosphere by driving the suction pump. The In normal times when recording is performed, the exhaust valve 102 is always pressed downward by the coil spring 103, and the exhaust outlet portion 101b is brought into contact with the valve portion 102a and the valve seat surface. Closed and valve closed.

  The air accumulated in the upper spaces of the other ink outlet paths 51M, 51Y, 51C is similarly sucked and discharged to the atmosphere in the same manner. Here, although there are two ink outlet paths 51Ya and 51Yb for yellow ink, the flow of air to the ink outlet path 51Ya side is suppressed by the protruding rib 49, and air is guided to the ink outlet path 51Yb side. In effect, air is accumulated in the upper space of one ink outlet path 51Yb. Therefore, the air amount in the upper space can be managed in the same manner as other inks. That is, the time until the air accumulated in the upper spaces of these ink outlet paths 51M, 51Y, 51C becomes a predetermined amount or more is obtained in advance by experiments or the like, and the cap member 123 is exhausted every predetermined time. It is possible to control the amount of air in the upper space by connecting to 45 and discharging air with a suction pump. Alternatively, an air discharge operation may be performed by detecting the air amount with a known sensor.

  In this way, it is possible to discharge the air accumulated in the upper spaces of the respective ink outlet paths 51M to 51C to the outside and avoid accumulating a certain amount or more of air in the upper spaces, and the ink outlet paths 51M to 51M. A large amount of air is accumulated in the upper space of 51C, and the probability that the air is sucked into the recording head 5 and recording becomes impossible or recording failure is reduced.

  The embodiment described above can be modified as follows.

  (A) In the above-described embodiment, the protruding rib 49 as the air guide means is provided at the upper part of the ink outlet path, but it can also be provided at the upper part of the communication part (ink guide path part 48Y). Moreover, it can also be set as the partition wall connected with the inner surface on either side instead of a protrusion rib.

  (B) In the above embodiment, the projecting rib 49 that hangs down from the upper surface in the ink outlet path is used as the air guiding means, and the upper end is supported on the upper surface, but the upper portion of the side edge is supported on the side surface. It can also be configured.

  (C) In the above embodiment, the protruding rib 49 as the air guiding means is provided on the upper tank portion 32 side, and the lower end thereof penetrates into the lower tank portion 33. It can be configured to be provided on the tank portion 33 side, and the upper end of the tank portion 33 can penetrate into the upper tank portion 33, or it can be divided into upper and lower tank portions 32, 33, and both tank portions 32, 33 are joined. At this time, a partition wall as air guiding means may be formed. In this case, the portion provided in the lower tank portion 33 may be a partition wall in which a cutout or an opening in which ink can flow is formed in the lower portion.

  (D) The ink storage chamber 41 for yellow ink communicates with the ink guide passage portion 48Y, but may be configured to communicate directly with one ink outlet passage 51Yb.

  (E) Although the air discharge ports 46Ya and 46Yb are provided for the ink discharge paths 51Ya and 51Yb, the air flow toward the ink discharge path 51Ya is suppressed, so the air discharge ports for the ink discharge path 51Yab are provided. The part 46Ya can be omitted.

  (F) In the above-described embodiment, the protruding rib 49 is used as the air guiding means, but the ceiling surface of the communicating portion (ink guide passage portion 48Y) is arranged such that one ink lead-out path 51Yb side is the other ink lead-out path 51Ya side. It is also possible to guide the air flow to one of the ink outlet paths 51Yb by inclining it so as to be higher.

  (G) In the embodiment, yellow, magenta, cyan, and black ink are stored in order from the top, but the order of the stored ink may be changed.

It is explanatory drawing which shows the main structure of the inkjet printer which concerns on this invention planarly. It is a top view of the head holder carrying a buffer tank. It is sectional drawing in the III-III line of FIG. FIG. 4 is an explanatory diagram of a recording head viewed from the direction A in FIG. 3. It is the top view which looked at the buffer tank from the upper side. It is the top view which looked at the upper tank part from the upper part. It is the top view which looked at the upper tank part from the downward direction. It is the top view which looked at the lower tank part from the upper part. It is the top view which looked at the lower tank part from the lower part. It is sectional drawing in the YY line of FIG. It is sectional drawing in the MM line | wire of FIG. It is sectional drawing in the CC line of FIG. It is sectional drawing in the BB line of FIG. It is sectional drawing in the XIV-XIV line | wire of FIG. (A) (b) is explanatory drawing of the effect | action of a protrusion rib, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 5 Recording head 21M-21B Ink inlet 31 Buffer tank 32 Upper tank 33 Lower tank 39M-39C Ink supply port 41-44 Ink storage chamber 46M-46B Air discharge port 48Y Ink guide passage (Communication Department)
49 Protruding rib 51M to 51C Ink lead-out path

Claims (6)

A recording head having a plurality of nozzles for ejecting ink droplets, a plurality of ink storage chambers for storing ink for each type, and an ink outlet path extending in the vertical direction to draw ink from the ink storage chambers The ink is supplied to the ink inlet port of the recording head through the ink supply port portion opened at the lower end portion of the ink outlet path, and is contained in the ink through the air outlet port portion opened at the upper end portion of the ink outlet path. In an inkjet printer configured to discharge the air that has been discharged,
The recording head includes two ink inlet portions for a specific ink, with a gap therebetween,
Among the ink outlet paths, two ink outlet paths corresponding to the two ink inlets for the specific ink are arranged apart from each other, and at least the upper parts of the ink outlet paths for the specific ink are at the tops of each other. Communicated with each other through the communication section,
When ink is led out from the ink storage chamber to the two ink lead-out paths with respect to the upper part of the ink lead-out path or the communication part, the air separated from the ink is supplied to one of the two ink lead-out paths. An ink jet printer, characterized in that air guide means is provided mainly for guiding to the outlet path side and suppressing flow to the other ink outlet path side. The ink lead-out paths are arranged substantially in a line along the edge of the recording head in a direction perpendicular to the nozzle row direction,
An ink outlet path for another ink is disposed between two ink outlet paths for the specific ink,
The inkjet printer according to claim 1, wherein the communication unit is provided so as to bypass an ink lead-out path for the other ink.   The air guide means hangs down from the upper part of the ink outlet path or from the communication part, suppresses the air flow toward the other ink outlet path at the upper part, and opens a gap allowing the ink to flow at the lower part. The ink jet printer according to claim 1, wherein the projecting rib is located on the right side.   2. The ink storage chamber for the specific ink communicates with the one ink outlet path side or the one of the ink outlet path side with respect to the air guiding means. The inkjet printer according to any one of 3. A plurality of the ink storage chambers are provided in the buffer tank so as to store ink according to type, and the buffer tank is formed by joining the upper tank portion and the lower tank portion,
The lower tank portion is formed with the ink supply port portion and a lower portion of the ink lead-out path communicating with the ink supply port portion, while the upper tank portion is formed with the air discharge port portion and the ink lead-out communicated therewith. The ink jet printer according to any one of claims 1 to 4, wherein the air guide means is formed in addition to the upper portion of the path. The air discharge port portion is opened only at the upper part of the one ink outlet path among the two ink outlet paths.
6. The ink jet printer according to claim 1, wherein the air accumulated in the upper space of the ink outlet path is discharged to the outside through the air discharge port.

Images