JP4793038B2 - Inkjet printer - Google Patents

Description

  The present invention relates to an ink jet printer.

  As an inkjet printer that performs recording by ejecting ink onto a recording medium, a recording head having a plurality of nozzle groups that eject ink droplets, and a buffer tank that temporarily stores ink to be supplied to the nozzle groups from an ink supply source There are known (for example, see Patent Document 1).

  In such an ink jet printer, the buffer tank is configured by joining two case parts (synthetic resin parts) by ultrasonic welding or the like.

  In the configuration of Patent Document 1, an ink storage chamber for storing one of a plurality of types of ink is formed flat in the horizontal direction, and the other three ink storage chambers are vertically arranged on the upper surface of the former ink storage chamber. It is formed high in the direction. The former ink storage chamber can take a wide surface composed of a flexible film and has a large effect of absorbing ink pressure fluctuations. However, the latter three ink storage chambers are made of a flexible film. The area constituted by the above becomes small, and the effect of absorbing the pressure fluctuation of the ink is small. For this reason, there is a demand to make all the ink storage chambers have substantially the same shape and arrangement as the former ink storage chamber and to obtain the same pressure fluctuation absorbing effect for all types of ink.

In addition, in such a recording head of an ink jet printer, there is a demand for increasing the number of nozzles in order to increase printing speed and resolution.
JP 2005-280028 A

  Therefore, as described above, the present applicant configures a buffer tank by joining a plurality of tank portions each having an ink storage chamber in order to make all the ink storage chambers have substantially the same shape and arrangement. I thought.

  In addition, as the number of nozzles of the recording head, especially the number of rows increases, the size of the recording head increases in the horizontal width direction, so the size of the buffer tank also increases in the horizontal width direction. It becomes difficult to stably join.

  The present invention provides an ink jet printer in which, when a buffer tank is formed by joining two upper and lower tank portions each having the ink storage chamber, the two tank portions can be stably joined. Objective.

  According to the first aspect of the present invention, there is provided a recording head having a plurality of nozzle groups for ejecting ink droplets, a plurality of ink introduction paths for introducing inks by type from an ink supply source, and ink introduced through the ink introduction paths. A plurality of ink storage chambers to be stored, and a buffer tank having an ink lead-out path that extends in the vertical direction from each ink storage chamber and guides ink to the nozzle group, and each of the buffer tanks has an ink storage chamber. Two tank portions are joined to each other, and the lower tank portion of the two tank portions is formed with the ink lead-out path inside one side of the ink storage chamber. 1 tubular portion is provided, and the upper tank portion is provided with an extending portion that overlaps with the upper end of the first tubular portion to form the upper end portion of the ink lead-out path. U One tank section is provided with the ink introduction path, and an ink communication path that connects one of the ink introduction paths to the ink storage chamber of the other tank section from at least one of the two tank sections. A second cylindrical portion formed on the opposite side of the ink lead-out path across the ink storage chamber, the second cylindrical portion formed on the first side of the ink storage chamber. The first cylindrical portion and the extending portion are joined to each other in the state where the two tank portions are joined, arranged in the vicinity of both ends in a direction parallel to the side, and the second tubular shape. One of the introduction paths is connected to the ink storage chamber of the other tank part by joining the part to the other tank part.

  In this way, the lower tank part of the upper and lower two tank parts is provided with the first cylindrical part that internally forms the ink outlet path on one side of the ink storage chamber. Is provided with an extending portion that overlaps with the upper end of the first cylindrical portion and forms the upper end portion of the ink outlet path, and is opposite to the ink outlet path across the ink storage chamber. In the state where the second cylindrical portion protrudes from at least one tank portion in the vicinity of both ends in the direction parallel to one side of the ink storage chamber, and the upper and lower two tank portions are joined, the first cylinder And the second cylindrical part is joined to the other tank part so that one of the ink introduction paths is connected to the ink storage chamber of the other tank part. Therefore, at least four corners of the upper and lower two tank parts are connected to the first and second tanks. Utilizing Jo portion, it is possible to stably joined.

  According to a second aspect of the invention, there is provided the ink jet printer according to the first aspect, wherein the ink lead-out paths are arranged in a line along one side of the ink storage chamber, and the second cylindrical portion is the ink. It arrange | positions corresponding to the said 1st cylindrical part located in the right-and-left both ends among the lead-out paths, It is characterized by the above-mentioned.

  According to this configuration, the ink lead-out paths are arranged in a line along one side of the ink storage chamber, and the second cylindrical portions are located at both left and right ends of the ink lead-out path. The four corner portions of the two tank portions can be easily used as the joint portions by being arranged corresponding to the cylindrical portions.

  A third aspect of the invention is the ink jet printer according to the first or second aspect, wherein lower ends of the plurality of ink outlet paths in the lower tank portion are arranged on substantially the same plane and are opened as ink supply ports. It is connected to an ink inlet of the recording head.

  In this way, the ink supply port, which is the lower end of the ink lead-out path, is arranged on substantially the same plane, so that it is reliably connected to the ink inlet of the recording head.

  A fourth aspect of the present invention is the ink jet printer according to the third aspect, wherein an upper end of the plurality of ink outlet passages in the extended portion of the upper tank portion discharges air contained in the ink. It is characterized by being opened as an outlet.

  In this way, by using the upper ends of the plurality of ink outlet passages as air discharge ports in the extended portion of the upper tank portion, the air accumulated in the upper space of the air outlet passage can be easily released to the outside. Can be discharged.

  A fifth aspect of the present invention is the ink jet printer according to any one of the first to fourth aspects, wherein the recording head includes two specific ink inlets spaced apart from each other for the specific ink. An ink lead-out path for another ink is arranged between the two ink lead-out paths for the ink, and a communication portion that communicates at least the tops of the ink lead-out paths for the specific ink with each other is an ink for another ink. It is provided around the lead-out path, and the periphery of the communication part is also joined.

  By doing so, since the periphery of the communication portion provided around the ink lead-out path for another ink is also joined, the joining area increases and the joining strength increases.

  A sixth aspect of the present invention is the ink jet printer according to the fourth aspect, wherein an exhaust passage communicating with the air discharge port is formed on an upper surface of the upper tank portion, and the exhaust passage includes the exhaust passage. An exhaust device having valve means for opening and closing is connected.

  If it does in this way, an exhaust passage is formed using the upper surface of an upper tank part effectively, and the air discharged from an air exhaust port will be discharged outside by an exhaust device through an exhaust passage.

  A seventh aspect of the present invention is the ink jet printer according to the sixth aspect, wherein the exhaust device has a third cylindrical portion that accommodates the valve means as the one side of the ink storage chamber in the lower tank portion. The upper tank portion has a second extending portion that overlaps the upper end of the third cylindrical portion and forms the upper end portion of the exhaust device. And the downstream end part of the said exhaust passage is extended on the 2nd extension part, and is communicating in the said 3rd cylindrical part, It is characterized by the above-mentioned.

  In this way, the exhaust device can be provided in a state extending in the vertical direction on a side portion different from the one side of the ink storage chamber.

  The invention according to claim 8 is the ink jet printer according to any one of claims 1 to 7, wherein the plurality of ink storage chambers are arranged in a stacked state in the vertical direction, and each is wide in a horizontal direction perpendicular to the vertical direction. It has a flat shape having a surface, and has a flexible wall surface that can be bent by pressure fluctuation of ink on each wide surface.

  This makes it possible to increase the area of the one wall surface having flexibility while suppressing the height of the ink storage chamber in the stacking direction, which is advantageous in suppressing fluctuations in ink pressure and the like.

  The invention according to claim 9 is the ink jet printer according to any one of claims 1 to 5, wherein in each of the upper tank portion and the lower tank portion, a circumferential wall is provided above and below an intermediate wall portion that serves as a bottom surface of the ink storage chamber. The ink storage chambers are formed above and below each of the intermediate wall portions by closing the upper and lower end portions of the circumferential wall portion with the flexible wall surface.

  In this way, two ink storage chambers can be formed adjacent to each other using one intermediate wall portion.

A tenth aspect of the present invention is the ink jet printer according to the sixth or seventh aspect, wherein a plurality of the exhaust devices are provided corresponding to the number of the ink outlet paths, and the plurality of exhaust apparatuses are the first cylindrical portion, While the ink storage chamber and the second cylindrical portion are arranged in a row substantially parallel to the row, a locked portion is formed near the second extending portion of the upper tank portion at both ends in the row direction. A locking portion that is detachably locked to the locked portion is formed in the vicinity of the third cylindrical portion of the lower tank portion.

If it does in this way, the 2nd extension part of an upper tank part and the 3rd cylinder of a lower tank part by the engagement relation of a locking part and a locked part in the both ends of the column direction of an exhaust device and Jo portion is engaged, the junction position shifts is Ru is prevented.
The invention according to claim 11 is the ink jet printer according to any one of claims 1 to 10, wherein an engagement portion is provided in the upper tank portion and the lower tank portion is provided in the vicinity of the second cylindrical portion. Engaged parts that engage with the engaging part and restrict relative rotation of the upper tank part with respect to the lower tank part are formed.

  According to this configuration, the relative rotation of the upper tank portion with respect to the lower tank portion is restricted in the vicinity of the second cylindrical portion due to the engagement relationship between the engaging portion and the engaged portion. It is prevented that it shifts.

  As described above, according to the present invention, the lower cylindrical tank portion of the upper and lower two tank portions constituting the buffer tank has a first cylindrical portion that internally forms an ink outlet path on one side of the ink storage chamber. The upper tank portion is provided with an extending portion that overlaps with the upper end of the first cylindrical portion to form the upper end portion of the ink outlet passage, and the ink outlet passage is sandwiched between the ink storage chambers. A second cylindrical portion is formed to protrude from at least one tank portion in the vicinity of both ends in the opposite direction and parallel to one side of the ink storage chamber, and the upper and lower two tank portions are joined. The first cylindrical portion and the extending portion are joined to each other, the second cylindrical portion is joined to the other tank portion, and one of the ink introduction paths and the ink storage chamber of the other tank portion are connected to each other. So that the four corners of the upper and lower two tank parts are connected to the first and second tanks. Utilizing the cylindrical portion, it is possible to constitute the buffer tank and stably joined.

  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 inlets 21Ma, 21Mb, 21Ya, 21Yb, 21Ba, 21Bb, 21Ca, and 21Cb on the upper surface for each ink color. Two ink inlets 21Ma, 21Mb, 21Ba, 21Bb, 21Ca, and 21Cb for magenta ink, black ink, and cyan ink are arranged side by side, but two ink inlets 21Ya and 21Yb for yellow ink are The ink inflow ports 21Ba and 21Bb are sandwiched between them so as to be spaced apart from each other.

  The upper surfaces of the ink inlets 21M to 21C are covered with an ink filtering filter (not shown), and 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. These ink storage chambers 41 to 44 are parallel to each other and are arranged in a stacked state in the vertical direction, and have a flat shape having a wide surface in the horizontal direction perpendicular to the vertical direction. It has the films 61-64 which are flexible wall surfaces. That is, two ink storage chambers 41 to 44 are formed separately above and below the intermediate wall portions 34 and 35 of 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 lead-out paths 51M to 51C are formed with substantially the same length and extending in the stacking direction of the ink storage chambers 41 to 44, respectively. 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, air is favorably discharged from the ink that is about to flow into the ink inlets 21M to 21C of the recording head 5 from the respective ink storage chambers 41 to 44, as will be described later. The air is accumulated in the upper space 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 passes through the exhaust passages 71M to 71C through the air discharge ports 46M, 46Ya, 46B, 46Yb, and 46C formed at the upper ends of the ink outlet paths 51M to 51C. It is discharged 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 the first cylindrical portion 40b and the partition wall portion 40d that form the lower portions of the ink outlet paths 51M to 51C inside one side of the ink storage chambers 41 to 44. ing. On the other hand, the upper tank portion 32 is provided with a cylindrical portion 40a and a partition wall portion 40c which are extended portions that overlap the upper ends of the cylindrical portion 40b and the partition wall portion 40d and form the upper end portions of the ink outlet paths 51M to 51C. It has been. 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 ports 46M to 46B for discharging the air contained in the ink.

  By aligning the cylindrical 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 in this state, the ink outlet paths 51M to 51C. The upper side portion and the lower side portion are joined, and the ink outlet paths 51M to 51C are continuously formed across the upper and lower tank portions 32 and 33. At this time, the periphery of the ink guide passage portion 48Y is also joined. 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 inflow passages 53B, 53M, 53Y, and 53C having upstream ends connected to the ink flow passage openings 52B to 52C are formed on the lower surface of the extension 40e. Each of the ink inflow passages 53B to 53C is formed as a concave groove extending in the front-rear direction, and 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 inflow passages 53B to 53C is sealed with a film 54 (see FIG. 3). The film 54 serves as the bottom surface of each ink inflow passage 53B to 53C, and the ink inflow passages 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 inflow passages 53B to 53C are extended as shown in FIG. The ink introduction passages 55B, 55M, 55Y, and 55C that vertically penetrate the portion 40e are connected to ink introduction paths 56B, 56M, 56Y, and 56C formed on the upper surface of the extension 40e, respectively.

  The left and right ink introduction 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 introduction paths 56Y and 56Y. 56M is connected to the ink storage chambers 41 and 42 of the upper tank portion 32, respectively.

  Second cylindrical portions 57a and 57b project from the opposing surfaces of the upper and lower tank portions 32 and 33 at positions where they overlap the rear ends of the left and right ink introduction paths 56C and 56B in plan view. The upper ends of the ink communication paths 58C and 58B that penetrate the portions 57a and 57b are connected to the rear ends of the ink introduction paths 56C and 56B. The second cylindrical portions 57a and 57b are arranged in a line 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 chamber. 40a and 40b (ink outlet paths 51M to 51C) are arranged corresponding to the ink outlet paths 51M and 51C located at the left and right ends in the front-rear direction.

  The cylindrical 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 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 introduction path of the upper tank portion 32 is obtained. 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.

  Also, by joining the protruding portions 57aa, 57ab, 57ba, 57bb of the cylindrical portions 57a, 57b together with the cylindrical portions 40a, 40b, the upper and lower tank portions 32, 33 are mutually connected. Connected and integrated.

  In addition, in the vicinity of the cylindrical portions 57 a and 57 b, the engaging portion 32 a formed to protrude from the upper tank portion 32 is connected to the engaged portion 33 a formed to protrude from the lower tank portion 33 to the lower tank portion 33. The upper tank part 32 is in contact with and engaged in a direction that restricts relative rotation of the upper tank part 32. 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 is formed which is closed by a film 61 as a possible flexible wall surface and is a flat space. 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 introduction path 56 </ b> Y opens as an ink inlet 41 b in the vicinity of a substantially central portion of the front portion of the circumferential 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 inlets 21Ya and 21Yb for the yellow ink, so that they are arranged apart from each other. 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 introduction paths 56M to 56Y, the connection outlet path 65M, the ink passage section 70B, and the exhaust passages 71M to 71B. It has stopped. That is, the upper surfaces of the side walls that define the outer peripheries of the ink introduction paths 56M to 56Y, the connection derivation path 65M, the ink passage portion 70B, and the exhaust passages 71M to 71B described later are the same as the upper surface of the circumferential wall portion 41a around the ink storage chamber 41. The film 61 is formed on a flat surface, and 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 introduction 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 inlet passage 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 introduction path 56 </ b> C formed in the upper tank portion 32 on the upper surface of the intermediate wall portion 34 is cyan through the ink communication path 58 </ b> C and the communication path 66 that penetrate in the stacking direction of the upper and lower tank portions 32 and 33. 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 the bottom to the top. (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 portions of the ink supply ports 39M to 39C arranged in a line, and screws 23 are inserted into the through holes 24a to 24c, respectively. ing. 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 inflow 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 inlets 21Ya and 21Yb of the recording head 5 from the ink supply ports 39Ya and 39Yb.

  As shown in FIGS. 6 and 7, the magenta ink is introduced from the ink flow path opening 52 </ b> M through the ink inflow paths 53 </ b> M and 56 </ b> M into the ink storage chamber 42 below the upper tank portion 32 from the ink inlet 42 b. 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 inlet of the recording head 5 from the ink supply ports 39Ma and 39Mb. It is supplied to 21Ma and 21Mb.

  As shown in FIGS. 6, 7, and 8, the cyan ink passes through the ink inflow passages 53 </ b> C and 56 </ b> C from the ink passage opening 52 </ b> C and passes through the ink tanks 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, the ink 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 flowing out from the ink outlet 43c of the ink storage chamber 43 reaches the ink outlet path 51C via the connection outlet path 65C, and is supplied from the ink supply ports 39Ca and 39Cb to the ink inlets 21Ca and 21C of the recording head 5. Supplied to 21Cb.

  As shown in FIGS. 6, 7, and 11, the black ink passes through the ink flow path opening 52 </ b> B, the ink inflow 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 (the 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 inlets 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 extending in the vertical direction, so that air is well separated from the ink in each of the ink outlet paths 51M to 51C. The air trapped by the filters provided at the ink inlets 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 the exhaust passages through the air outlets 46M to 46B. It can be discharged to 71M-71B.

  The ink is supplied to the ink inlets 21M to 21C of the recording head 5 as described above while scanning the ink storage chambers 41 to 44 and the recording head 5 with respect to the recording medium. However, since one of the upper and lower wall surfaces of the ink storage chambers 41 to 44 is a flexible wall surface film 61 to 64, variation in ink pressure or the like is effectively suppressed by deformation of the films 61 to 64. High quality recording can be performed. In particular, since the films 61 to 64 are provided as mutually parallel wall surfaces that define the ink storage chambers 41 to 44, the area of the flexible wall surface can be increased while suppressing the height in the stacking direction, and the ink pressure can be increased. This is advantageous in suppressing fluctuations in

(Structure of exhaust passages 71M to 71B)
The upper ends of the ink outlet paths 51M to 51C located above the ink supply ports 39M to 39C are connected to air discharge ports 46M to 46C formed on the upper surface of the upper tank portion 32, as shown in FIGS. Each ink in the exhaust device 45 disposed on one side of the buffer area S2 through the exhaust passages 71M, 71Y, 71B, 71C formed as concave grooves along the upper surface of the upper tank portion 32. Each color is connected to the upper end of each exhaust device (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 way, the air discharge ports 71M to 71C formed on the upper surface of the upper tank portion 32 by the air discharge ports 46M to 46C positioned at the upper ends of the ink outlet paths 51M to 51C and the upper ends of the exhaust devices of the exhaust device portion 45 are formed. Connected to each other. 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. Is then connected to the upper end of each exhaust device of the exhaust device section 45.

  By driving and controlling the exhaust devices to appropriately open the exhaust valves, the air accumulated in the upper spaces of the ink outlet passages 51M to 51C is discharged to the outside through the exhaust passages 71M to 71C.

(Schematic structure of exhaust unit and maintenance unit)
A plurality of exhaust devices of the exhaust device section 45 are provided corresponding to the number of ink lead-out paths 51M to 51C, and these are cylindrical portions from the ink lead-out area S3 through the buffer area S2 toward the ink introduction area S1. 40a and 40b, the ink storage chambers 41 to 44, and the columns formed by the cylindrical portions 57a and 57b are arranged in a line substantially in parallel.

  Each exhaust device of the exhaust device section 45 is provided to extend from the upper and lower tank sections 32 and 33 via the arm sections 81 (81A and 81B), respectively, and the ink outlet paths 51M to 51C of the ink storage chambers 41 to 44 are provided. Are arranged on the right side different from the rear side provided in a row.

  The lower portion 82B of the exhaust valve box 82 of each exhaust device includes a third cylindrical portion 45b that accommodates an exhaust valve 102 (valve means), which will be described later, extending in the vertical direction, and the lower portion of the arm portion 81. It is coupled to the lower tank portion 33 via the portion 81B.

  On the other hand, the upper portion 82A of the exhaust valve box 82 is a cylindrical portion that is a second extending portion that forms the upper end portion of each exhaust device in the upper tank portion 32 so as to overlap the upper end of the third cylindrical portion 45b. 45a, and is coupled to the upper tank portion via the upper portion 81A of the arm portion 81. 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 portion 45a and communicate with the inside of the cylindrical portion 45b through the internal space of the cylindrical portion 45a.

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

  Further, in the lower portion 82B of the exhaust valve box 82, locking portions 33b are formed near the cylindrical portions 45a at both ends of the exhaust devices 45 in the arrangement direction of the exhaust devices, while in the upper portion 82A, the locking portions are formed. A locked hole portion 32b that is detachably locked to 33b is formed in the vicinity of the cylindrical portion 45b. With these engaged, the tubular portions 45a and 45b are joined to each other. As a result, the coil spring of each exhaust device (for example, the coil spring 103 for the black ink exhaust device 45B, on the line L1 (see FIG. 6) connecting the engaging portions of the engaging portion 33b and the engaging hole portion 32b, 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 the upper portion is joined during ultrasonic welding or the like. A misalignment between 82A and the lower portion 82B is avoided.

  For each of the exhaust passages 71M to 71B, an exhaust device section 45 including four exhaust devices having valve means for opening and closing the exhaust passage is provided in the downstream portion of each of the exhaust passages 71M to 71B. Since both have the same configuration, the exhaust device 45B 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, the recording head 5 serves as 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. The first cap member 122 (see FIG. 3) that covers the opening surfaces of the nozzles 35 to 38 in an openable and closable manner and the lower end surface of the exhaust valve box 82 (that is, the lower end opening surface of each small-diameter hole 101b) can be opened and closed individually. And a plurality of second cap members 123 that are covered. The cap members 122 and 123 are supported so as to be vertically movable by a vertical movement mechanism similar to a known maintenance unit. When the recording head 5 is moved to a standby position where recording is not performed, the cap members 122 and 123 are moved to the ascending position where the recording head 5 is in close contact with the nozzle opening surface and the lower end surface of the exhaust valve box 82. Move to the lowered position so as to be separated from The first cap member 122 is connected to a suction pump (not shown) as in a known maintenance unit, and is configured to suck and remove ink and foreign matters thickened from the nozzles 35 to 38 by driving the suction pump. It is said.

  Each second cap member 123 has a protruding shaft portion 121 protruding from the cap member 123. When the second cap member 123 is in close contact with the lower end surface of the exhaust valve box 82, the protruding shaft portion 121 causes the exhaust valve 102 to be coiled. The seal member 104 is pushed up against the urging force 103, and the sealing material 104 is separated from the opening end face 101C of the large-diameter hole 101A, so that the exhaust outlet 101b is opened.

  Each second cap member 123 is connected to the suction pump via an exhaust passage 124, and the air accumulated in the upper spaces of the ink outlet paths 51M to 51C is collectively sucked by the driving of the suction pump. To be discharged. In this way, the air accumulated in the upper spaces of the ink outlet paths 51M to 51C can be discharged to the outside.

  The first cap member 122 and the second cap member 123 are alternatively connected to the suction pump by a switching valve (not shown).

  In the above-described embodiment, each exhaust device of the exhaust device section 45 is formed integrally with the buffer tank 31 via the arm portion 81. However, each exhaust device of the exhaust device section is formed by configuring the exhaust passage with an air pipe. It is also possible to configure as a separate body.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 5 Recording head 21M-21B Ink inflow port 31 Buffer tank 32 Upper tank part 32a Engagement convex part 32b Locking hole part 33 Lower tank part 33a Engagement part 33b Locking part 34,35 Middle wall part 39M to 39C Ink supply port 40a Tubular part (extension part)
40b 1st cylindrical part 41-44 Ink storage chamber 41a-44a Circumferential wall part 45 Exhaust apparatus part 45B Exhaust apparatus 45a Cylindrical part (2nd extension part)
45b 3rd cylindrical part 46M-46B Air discharge port 51M-51C Ink extraction path 56B-56C Ink introduction path 57a, 57b 2nd cylindrical part 58B, 58C Ink communication path 61-64 Film (flexible wall surface) )
102 Exhaust valve

Claims (11)

A recording head having a plurality of nozzle groups for ejecting ink droplets, a plurality of ink introduction paths for introducing inks by type from an ink supply source, and a plurality of ink storage chambers for storing ink introduced through the ink introduction paths A buffer tank extending in the vertical direction from each of the ink storage chambers and having an ink outlet path for leading ink to the nozzle group,
The buffer tank is configured by joining two upper and lower tank portions each having the ink storage chamber, and the lower tank portion of the two tank portions includes the ink storage chamber. A first cylindrical part that forms the ink outlet path inside is provided on one side, and the upper tank part extends over the upper end of the first cylindrical part to form the upper end part of the ink outlet path. The exit part is provided,
One of the two tank parts is provided with the ink introduction path, and from at least one of the two tank parts, one of the ink introduction paths and an ink storage chamber of the other tank part are provided. A second cylindrical portion that internally forms an ink communication path for connecting the ink is projected and formed, and the second cylindrical portion is on the opposite side of the ink outlet path from the ink storage chamber. Disposed near both ends in a direction parallel to one side of the ink storage chamber,
In a state where the two tank parts are joined, the first cylindrical part and the extension part are joined to each other, and the second cylindrical part is joined to the other tank part to introduce the introduction. An ink jet printer, wherein one of the paths is connected to an ink storage chamber of the other tank portion. The ink outlet passages are arranged in a line along one side of the ink storage chamber,
The inkjet printer according to claim 1, wherein the second cylindrical portion is disposed corresponding to the first cylindrical portion located at both left and right ends of the ink outlet path.   The lower end of the plurality of ink outlet paths in the lower tank portion is disposed substantially on the same plane, is opened as an ink supply port, and is connected to an ink inlet port of the recording head. The ink jet printer according to 1 or 2.   4. The inkjet according to claim 3, wherein upper ends of the plurality of ink outlet paths are opened as air discharge ports for discharging air contained in the ink in the extended portion of the upper tank portion. Printer. The recording head comprises two ink inlets spaced apart for a particular ink;
An ink lead-out path for another ink is arranged between two ink lead-out paths for the specific ink, and a communication portion that communicates at least the upper parts of the ink lead-out paths for the specific ink with each other is different. The inkjet printer according to any one of claims 1 to 4, wherein the inkjet printer is provided around the ink lead-out path, and the periphery of the communication portion is also joined.   An exhaust passage communicating with the air discharge port is formed on the upper surface of the upper tank portion, and an exhaust device having valve means for opening and closing the exhaust passage is connected to the exhaust passage. The inkjet printer according to claim 4. The exhaust device includes a third cylindrical portion that accommodates the valve means in a state of extending in a vertical direction on a side portion of the lower tank portion that is different from the one side of the ink storage chamber,
The upper tank portion has a second extending portion that forms an upper end portion of the exhaust device so as to overlap an upper end of the third cylindrical portion, and a downstream end portion of the exhaust passage is a second extension portion thereof. The ink jet printer according to claim 6, wherein the ink jet printer extends on the protruding portion and communicates with the inside of the third cylindrical portion.   The plurality of ink storage chambers are arranged in a stacked state in the vertical direction, have a flat shape having a wide surface in the horizontal direction perpendicular to the vertical direction, and are flexible so that each wide surface can be bent due to ink pressure fluctuations. The inkjet printer according to claim 1, wherein the inkjet printer has a wall surface.   In each of the upper tank portion and the lower tank portion, a surrounding wall portion is provided above and below an intermediate wall portion that becomes the bottom surface of the ink storage chamber, and the upper and lower ends of the surrounding wall portion are closed by the flexible wall surface. 6. The ink jet printer according to claim 1, wherein the ink storage chambers are formed above and below each of the intermediate wall portions. A plurality of the exhaust devices are provided corresponding to the number of the ink outlet passages, and they are arranged in a line substantially parallel to the row formed by the first cylindrical portion, the ink storage chamber, and the second cylindrical portion. is arranged, in its column direction ends, the one second engaging portion in the vicinity of the extending portion of the upper tank portion is formed, the near third cylindrical portion of the lower tank portion engaged the ink jet printer according to claim 6 or 7, characterized in that the locking portion to be locked detachably engaged is formed on the part. In the vicinity of the second cylindrical portion, the engaging portion to the upper tank portion, restricting the relative rotation of the upper tank portion to engage the lower tank portion to the engaging portion to the lower tank portion The ink-jet printer according to claim 1, wherein the engaged portions are respectively formed.

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