JP2005324357A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid that residual ink drops on a recording medium at the time of moving (or at the time of recording) of a recording head by removing the ink remaining inside an exhausting valve means at the time of an exhaustion purge. <P>SOLUTION: When the recording head 11 moves to a waiting position where recording is not carried out, a cap member 72 moves to a first position where an exhaustion port of the exhausting valve means 15 is tightly closed. At the position, the first exhaustion operation is carried out to bring the exhausting valve means 15 into a valve open state and discharge the air separated in a buffer tank 14 to the outside through exhaustion passages 41a-41d, and then the second exhaustion operation is carried out to bring the exhausting valve means 15 into a valve closure state and discharge the air inside of the exhausting valve means 15 together with the atmosphere introduced from the outside. At positions other than the waiting position, the cap member 72 moves to a second position isolated from the exhaustion port of the exhausting valve means 15, and the recording head 11 carries out the recording action to a sheet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet printer, and more particularly to an ink jet printer capable of separating and retaining bubbles separated in an ink flow path and discharging the bubbles to the outside.

  In order to ensure thinness as a product, there is a demand for reducing the thickness of the carriage, that is, for a configuration in which the ink tank is not mounted on the carriage. In order to satisfy this requirement, it is necessary to provide an ink tank outside the carriage, for example, in a printer frame, and supply the ink in the ink tank to a recording head on the carriage via an ink supply tube.

  In an ink jet printer using such an ink supply tube, it is inevitable that air permeates through the tube and dissolves in the ink due to the characteristics of the material constituting the tube. Therefore, a so-called exhaust purge is required in which a bubble storage chamber is provided on the upstream side of the recording head, and the bubbles are separated from the ink in the bubble storage chamber to remove the bubbles.

  As a technique for removing bubbles in an ink jet printer using an ink supply tube, a manifold (corresponding to a bubble storage chamber) is provided above the recording head, an ink tank and a circulation pump are provided on the stationary position side, and this circulation pump is driven. What was comprised so that a bubble might be removed is known (for example, refer patent document 1).

  The technique described in Patent Document 1 requires a return tube from the circulation pump to the ink tank in order to circulate the ink, and there is a problem that the apparatus becomes large and complicated.

  In addition, there is also known a method in which air separated as bubbles in the ink supply tube is accumulated in an upper part of a tank mounted on the carriage, discharged by an exhaust pump, and after discharge, the tank is sealed by an exhaust valve (for example, Patent Document 2).

The inventor of the present invention has conducted research to satisfy the demand for making the exhaust valve structure as simple as possible in such an ink jet printer, and as a result, in the passage hole which is a part of the exhaust passage communicating with the bubble storage chamber, By providing a valve body along the axial direction of the passage hole and displacing the valve body with the operation member, the bubbles in the bubble storage chamber can be easily discharged by connecting or blocking the exhaust passage. We have developed an exhaust valve means that makes this possible.
JP 2000-103084 A (see paragraphs 0026 to 0031 and FIG. 1) Japanese Patent Laid-Open No. 2002-240310 (see paragraphs 0006 to 0018 and FIG. 5)

  In such a structure in which the valve body is moved by the operating member, when the valve body is moved to open the valve and the bubbles in the buffer tank are exhausted, a part of the ink discharged together with the bubbles is There may be cases where it remains inside the exhaust valve means or around the operating member for operating it. Such residual ink may fall on the recording medium when the recording head is moved (or during recording).

  The present invention provides an ink jet printer which removes ink remaining in the exhaust valve means during exhaust purge and prevents the residual ink from dropping on the recording medium when the recording head moves (or at the time of recording). provide.

  According to a first aspect of the present invention, there is provided a recording head for recording on a recording medium by ejecting ink from nozzles, an ink tank for storing ink supplied to the recording head, and supplying ink from the ink tank to the recording head. An ink jet printer comprising: an ink flow path, a buffer tank for storing ink supplied through the ink flow path, and exhaust valve means capable of exhausting the air separated in the buffer tank to the outside through an exhaust passage. A first exhaust operation for sealing the exhaust port of the exhaust valve means with a cap member and opening the exhaust valve means to open the air separated in the buffer tank through the exhaust passage. The exhaust port of the exhaust valve means is kept sealed by the cap member and the exhaust valve means is closed. To, and having a second exhaust operation for exhausting the interior of said exhaust valve means together with the air introduced from the outside. That is, according to the present invention, in addition to the first exhaust operation for removing bubbles in the buffer tank, the second exhaust operation for removing ink remaining in the exhaust valve means by the exhaust operation is performed.

  In this way, for example, when the recording head moves to a position other than the recording area where recording is performed, the exhaust port of the exhaust valve means is first sealed with the cap member, and the exhaust valve means is opened so that the buffer tank A first exhaust operation for exhausting the air separated inside through the exhaust passage is performed. Then, a second exhaust operation is performed in which the exhaust port of the exhaust valve means is maintained sealed by the cap member and the exhaust valve means is closed to exhaust the inside of the exhaust valve means together with the air introduced from the outside. The ink remaining inside the exhaust valve means is removed by suction.

  Therefore, during the first exhaust operation (exhaust purge), the ink remaining in the exhaust valve means is removed by the second exhaust operation and remains on the recording medium when the recording head moves (or during recording). Ink is prevented from falling.

  According to a second aspect of the invention, there is provided a recording head for recording on a recording medium by ejecting ink from a nozzle, an ink tank for storing ink supplied to the recording head, and supplying ink from the ink tank to the recording head. In an ink jet printer comprising: an ink flow path; a buffer tank that stores ink supplied through the ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage. A maintenance unit that seals an exhaust port of the exhaust valve means with a cap member and opens the exhaust valve means to exhaust the air separated in the buffer tank to the outside through the exhaust passage; and By controlling, the air separated in the buffer tank was exhausted Said exhaust valve means as a valve closed state, characterized in that it comprises a control means for evacuating the inside of said exhaust valve means together with the air introduced from the outside into. That is, according to the present invention, in addition to exhaust for removing bubbles in the buffer tank, exhaust for removing ink remaining in the exhaust valve means by the exhaust is performed by a common maintenance unit.

  According to this configuration, the exhaust port of the exhaust valve means is sealed with the cap member, and the exhaust valve means is opened to exhaust the air separated in the buffer tank to the outside through the exhaust passage. By controlling the above, after the air separated in the buffer tank is exhausted, the exhaust valve means is closed, and the inside of the exhaust valve means can be exhausted together with the air introduced from the outside. Therefore, the ink remaining in the exhaust valve means when the air separated in the buffer tank is exhausted is removed by the exhaust performed using the maintenance unit that performs the exhaust.

  According to a third aspect of the present invention, there is provided a recording head for recording on a recording medium by ejecting ink from a nozzle, an ink tank for storing ink supplied to the recording head, and supplying ink from the ink tank to the recording head. In an ink jet printer comprising: an ink flow path; a buffer tank that stores ink supplied through the ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage. A valve opening / closing means for opening and closing the exhaust valve means; a cap member capable of sealing the exhaust port of the exhaust valve means; a first position for sealing the exhaust port of the exhaust valve means; and exhaust of the exhaust valve means A first moving means for moving the cap member between a second position spaced apart from the mouth, and a suction pump connected to the cap member; And when the recording head is connected to the valve opening / closing means, the first moving means and the suction pump and moves to a standby position where recording is not performed, the cap member is moved to the first position, and the exhaust valve means A first exhaust operation for exhausting the air separated in the buffer tank to the outside through an exhaust passage with the valve open, and the inside of the exhaust valve means together with the atmosphere introduced from the outside with the exhaust valve means closed Control means for performing a second exhaust operation for exhausting the air.

  In this way, when the recording head moves to the standby position where recording is not performed, the cap member is moved to the first position, and the exhaust port of the exhaust valve means is sealed. In this state, first, a first exhaust operation is performed in which the exhaust valve means is opened and the air separated in the buffer tank is exhausted to the outside through the exhaust passage. Then, in the valve closed state, a second exhaust operation for exhausting the inside of the exhaust valve means together with the air introduced from the outside is performed, and the ink remaining inside the exhaust valve means is removed during the first exhaust operation. Removed.

  According to a fourth aspect of the present invention, in the ink jet printer according to the third aspect, the buffer tank has a reservoir for each of a plurality of types of ink, and the exhaust passage and the exhaust valve means exist for each of the reservoirs. The exhaust valve means is opened and closed by movement of the valve body in the exhaust passage direction, and is locked to a casing of the exhaust valve means so as to be movable in the exhaust passage direction. An operation member having a plurality of operation portions corresponding to the body, wherein the exhaust valve means includes a movable member, and includes a second moving means for moving the operation member in the direction by the movable member, and the cap member Is positioned downstream of the operation member in the first position, and the second exhaust operation exhausts the periphery of the operation member.

  According to this configuration, the operating member is provided in the casing of the exhaust valve means so as to be movable in the direction of the exhaust passage, and the operating member has a plurality of operating portions corresponding to the valve body of the exhaust valve means. By moving the operation member in the direction by the movable member of the means, the plurality of exhaust valve means are easily opened and closed simultaneously. Further, the second exhaust operation exhausts the inside of the exhaust valve means and around the operation member, and the ink remaining on them is removed.

  According to a fifth aspect of the present invention, in the ink jet printer according to the fourth aspect of the present invention, a guide hole is provided in the casing of the exhaust valve means, and an engaging portion is slidably engaged with the guide hole in the operation member. Provided, the guide hole portion is provided with an atmospheric communication hole that is closed during the first exhaust operation.

  In this way, the engaging portion of the operating member is slidably engaged with the guide hole portion (provided in the casing of the exhaust valve means) so that the engaging portion and the slide hole portion are engaged. The movement of the operation member is guided. Therefore, the exhaust valve means can be opened and closed smoothly. Further, by providing an air communication hole that is closed at the time of the first exhaust operation in the guide hole portion, the air is released through the air communication hole at the time of the second exhaust operation without affecting the first exhaust operation. Can be introduced from outside.

  According to a sixth aspect of the invention, in the ink jet printer according to the fourth or fifth aspect, the operation member is provided only for a part of the exhaust valve means, and the remaining exhaust valve means is provided in the valve body. It is set as the structure by which another operation member which has a corresponding operation part is provided. In this case, the separate operation member does not need to be moved by the movable member of the moving unit, and may be moved directly by the moving unit.

  In this way, the exhaust valve means is grouped into a part of the exhaust valve means and the remaining exhaust valve means according to the flow resistance, etc., so that the exhaust valve means is an optimum mode for each group. Thus, the first and second exhausts can be performed.

  A seventh aspect of the invention is the ink jet printer according to the fourth or fifth aspect, wherein the engaging portion of the operating member is arranged at the center of the operating portion member.

  According to this configuration, since the engaging portion that guides the movement of the operation member is arranged at the center of the operation member, the operation member moves in a balanced manner without being inclined during the movement.

  According to an eighth aspect of the present invention, there is provided a recording head for recording on a recording medium by ejecting ink from a nozzle, an ink tank for storing ink supplied to the recording head, and supplying ink from the ink tank to the recording head. In an ink jet printer comprising: an ink flow path; a buffer tank that stores ink supplied through the ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage. Valve opening / closing means for opening / closing the exhaust valve means, a cap member capable of sealing the exhaust port of the exhaust valve means, and exhaust of the exhaust valve means when the recording head moves to a standby position where recording is not performed. Between a first position that seals the mouth and a second position that is separated from the exhaust port of the exhaust valve means at a position other than the standby position, A first moving means for moving the cap member, a suction pump connected to the cap member, a valve opening / closing means, a first moving means, and a standby position connected to the suction pump and where the recording head does not perform recording A first exhaust operation that moves the cap member to a first position when the gas is moved to the first position and exhausts the air separated in the buffer tank to the outside through an exhaust passage with the exhaust valve means opened. Control means for performing a second exhaust operation for exhausting the inside of the exhaust valve means together with the air introduced from the outside, with the cap member positioned slightly away from the exhaust port of the exhaust valve means. Features.

  In this case, the cap member is located at a position slightly away from the exhaust port of the exhaust valve means, and the second exhaust operation for exhausting the inside of the exhaust valve means together with the atmosphere introduced through the gap is performed. It is not necessary to provide an air communication hole or the like in the casing of the exhaust valve means in order to introduce the air from outside.

  In the present invention, as described above, after performing the first exhaust operation for exhausting the air separated in the buffer tank to the outside through the exhaust passage, the exhaust valve means has the exhaust port sealed with a cap member. Since the valve means is closed, the second exhaust operation for exhausting the inside of the exhaust valve means together with the air introduced from the outside is performed, so that it remains in the exhaust valve means by the first exhaust operation. It is possible to remove the remaining ink by the second exhaust operation, and it is possible to avoid the residual ink from dropping on the recording medium when the recording head moves (or at the time of recording).

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

  FIG. 1 is a schematic configuration diagram showing main components of an inkjet printer according to the present invention, FIG. 2 is a bottom view of an inkjet printer head, and FIG. 3 is an exploded perspective view of a recording head, a reinforcing frame, a head holder, and a buffer tank. .

  As shown in FIGS. 1 to 3, an inkjet printer 100 includes, as an inkjet printer head 1, a recording head 11 that is an ink jet type that ejects ink from nozzle holes and has a thin plate shape, and a synthetic resin on which the recording head 11 is mounted. And a head holder 12 formed of a material. The head holder 12 functions as a carriage that moves relative to the paper P (recording medium). The ink is supplied from an ink tank (not shown) to the buffer tank 14 mounted on the head holder 12 via the ink supply tubes 13a to 13d (ink flow paths), temporarily stored, and then passes through the buffer tank 14. The recording head 11 is configured to supply ink. The ink tank is detachably mounted on a printer frame (not shown) and stores a large amount of ink to be supplied to the recording head 11. Although not specifically shown, a plurality of ink tanks (individual colors, that is, ink tanks for black, cyan, magenta, and yellow) are provided in the printer frame for full-color recording.

  The head holder 12 is slidably supported by a rear guide member 2A and a front guide member 2B which are provided in parallel in the front and rear of the printer frame and extend in the left-right direction of the frame. The rear guide member 2A has a substantially L-shaped cross section orthogonal to the slide movement direction, and the front guide member 2B has a horizontal surface extending in the slide movement direction. A part of the endless timing belt 4 wound between the driving pulley 3A and the driven pulley 3B is connected to the head holder 12, and the driving pulley 3A is rotationally driven by the driving motor 5, thereby the head The holder 12 is configured to reciprocate in the horizontal direction of the frame along the guide members 2 </ b> A and 2 </ b> B via the timing belt 4. The upper part of the head holder 12 is covered with a cover 24. Although not specifically shown, the paper P can be recorded in a direction (arrow A direction in FIG. 1) perpendicular to the moving direction of the head holder 12 on the lower surface side of the recording head 11 by a known paper transport mechanism. It is conveyed by. In the printer frame, a maintenance unit 70 described later (the nozzle surface is cleaned, a recovery process for selectively sucking ink for each color, and bubbles (air) in the buffer tank 14 are contained. In addition to performing removal processing to remove, an ink receiving portion (not shown) (ink discharge (flushing) for preventing clogging of nozzles periodically during a recording operation) is provided.

  On the lower surface of the recording head 11, two rows of black ink (BK) nozzles 16 a and a row of cyan ink (C) nozzles 16 b from the left side in FIG. 2 (view of the recording head 11 viewed from the lower surface), The row of nozzles 16c for yellow ink (Y) and the row of nozzles 16d for magenta ink (M) are formed long in a direction orthogonal to the moving direction (main scanning direction) of the head holder 12. The nozzles 16a to 16d are exposed downward so as to face the upper surface of the paper P.

  At one end side of the recording head 11, as shown in FIG. 3, ink supply ports 18a to 18d of the cavity unit 17 are opened in rows on the upper surface and provided for each ink color (four colors in this embodiment). It has been. The ink is distributed through the ink supply channels extending from the ink supply ports 18a to 18d, and the ink is ejected from the nozzles 16a to 16d by driving the piezoelectric actuator 19. The ink supply port 18a for black ink (BK) has a larger opening area than the ink supply ports 18b to 18d for cyan ink (C), yellow ink (Y), and magenta ink (M). .

  In the recording head 11, the outer shape of the piezoelectric actuator 19 is made smaller than the outer shape of the cavity unit 17 in a plan view, and the ink supply ports 18 a to 18 d are included when the piezoelectric actuator 19 is stacked on the back surface of the cavity unit 17. The back surface of the cavity unit 17 around the piezoelectric actuator 19 is exposed on the back surface side of the recording head 11.

  A flexible flat cable 20 that applies a voltage to the actuator 19 is fixed to the upper surface of the piezoelectric actuator 19. The flexible flat cable 20 includes a driver IC 21 and is electrically connected to a printed circuit board 22 (see FIG. 5) provided on the upper side of the buffer tank 14. The printed board 22 is configured to be connected to a printed board (not shown) on the printer frame side via another flexible flat cable 20 '(see FIG. 1). Since the driver IC 21 generates heat, an aluminum alloy heat sink 23 is pressed against the driver IC 21 to cool it (see FIG. 6), and the driver IC 21 is naturally cooled via the heat sink 23.

  As shown in FIGS. 4 to 6, the buffer tank 14 divides the inside of the main body case 25 with a partition wall so that a plurality of independent bubble storage chambers (reservoirs) for each ink color, that is, black ink ( BK) bubble storage chamber 31a, cyan ink (C) bubble storage chamber 31b, yellow ink (Y) bubble storage chamber 31c, and magenta ink (M) bubble storage chamber 31d.

  The main body case 25 of the buffer tank 14 includes a box-shaped lower case 26 whose upper surface is opened, and an upper case 27 that covers the upper surface of the lower case 26 and is fixed to the lower case 26. Both the lower case 26 and the upper case 27 are injection-molded with a synthetic resin material and are liquid-tightly coupled by ultrasonic welding or the like. By combining these two cases 26 and 27, bubble storage chambers 31a to 31d are formed. The bubble storage chambers 31a to 31d include not only the case where they are each formed by a single chamber, but also the case where each chamber is constituted by a plurality of divided chambers. And each bubble storage chamber 31a-31d is connected to the ink outflow port 32a-32d for each ink color in those edge parts.

  A bottom plate 12a, which is a bottom wall of the head holder 12, is substantially parallel to the back surface of the recording head 11, and the recording head 11 is bonded to the bottom surface of the bottom plate 12a. Also, on the upper side of the bottom plate 12 a of the head holder 12, a buffer tank 14 for temporarily storing ink and an exhaust valve means 15 for exhausting air in the bubble storage chambers 31 a to 31 d of the buffer tank 14 are mounted. Has been. The exhaust valve means 15 is provided for each of the bubble storage chambers 31a to 31d.

  The ink outlets 32a to 32d are arranged side by side on the lower surface of the lower case 26, and are opened downward at a position protruding downward from the bottom plate 12a. On the other hand, the cavity unit 17 (recording head 11) has a plurality of ink supply ports 18a to 18d communicating with the end portions of the ink supply channels (manifolds) for the respective ink colors on the upper surface facing the ink outlets 32a to 32d. We are prepared for position. The ink outlets 32a to 32d of the bubble storage chambers 31a to 31d pass through the ink passage holes 33b to 33e provided in the reinforcing frame 33, and elastic such as rubber packing to the ink supply ports 18a to 18d of the recording head 11. It communicates via a sealing material 34.

  The recording head 11 is fixed to the lower side of the head holder 12 with a frame-shaped reinforcing frame 33 interposed on the back surface thereof. The reinforcing frame 33 has a flat thin plate shape along the back surface of the recording head 11, and the size of the central opening 33a in the reinforcing frame 33 is slightly larger than the outer shape of the piezoelectric actuator 19 in plan view, and the cavity It is formed smaller than the outer shape of the unit 17. The reinforcing frame 33 is bonded and fixed to the back surface of the cavity unit 17 so that the piezoelectric actuator 19 and the flexible flat cable 20 are positioned in the central opening 33a.

  The reinforcing frame 33 is made of metal (for example, SUS430) and is thicker than the cavity unit 17 and has a large rigidity. The reinforcing frame 33 is located at one end side of the reinforcing frame 33 corresponding to the ink supply ports 18 a to 18 d of the cavity unit 17, and the ink outlets 32 a to 32 d of the buffer tank 14 and the ink supply ports 18 a to 18 d of the cavity unit 17. Ink passage holes 33b to 33e are formed in a row.

  In order to eliminate the level difference between the recording head 11 and the reinforcing frame 33 and protect the recording head 11, a U-shaped protective cover 51 located around the recording head 11 is attached to the reinforcing frame 33. Yes.

  In addition, screw holes 33f and 33g are provided at corners of the reinforcing frame 33. In correspondence with the screw holes 33f and 33g, flange-like attachment portions 14a projecting in the outer peripheral direction are provided on the outer peripheral surface of the buffer tank 14, and attachment holes 14b are formed in the respective attachment portions 14a. Then, the screw 28 as a fastening member is screwed into the screw holes 33f and 33g through the mounting holes 14b, whereby the buffer tank 14 is fixed to the upper surface of the reinforcing frame 33 that is bonded and fixed to the lower surface of the bottom plate 12a. .

  A flange-like tank extension 27a protrudes laterally from the side surface of the buffer tank 14 (specifically, the upper case 27 of the buffer tank 14) on the side opposite to the portion where the ink outlets 32a to 32d are provided. Yes. As shown in FIGS. 3 and 4, the tank extension 27a has an ink flow path for each ink color, that is, for black ink (BK), cyan ink (C), yellow ink (Y), and magenta ink ( Each ink flow path 35a, 35b, 35c, 35d for M) is formed independently, and their downstream ends communicate with the bubble storage chambers 31a-31d, respectively. A holder extension portion 12b of the head holder 12 is provided below the tank extension portion 27a of the upper case 27 corresponding to the tank extension portion 27a. The holder extension 12b extends from the upper end of the box-shaped holder main body 12c in which the buffer tank 14 is accommodated, corresponding to the tank extension 27a. A tube joint 36 having an ink flow path for each ink color is elastically attached by a spring 37 to the distal end portions of both extension portions 27a and 12b. As a result, the upstream ends of the ink flow paths 35 a to 35 d communicate with the ink flow paths inside the tube joint 36.

  The tube joint 36 has tube connection ports 36a to 36d communicating with the respective ink flow paths inside. The tube connection ports 36a to 36d are connected to the ink supply tubes 13a to 13d with one end communicating with the ink tank. The other end of 13d is detachably connected. The tube joint 36 is integrally provided with a locking portion 36e for locking the flexible flat cable 20 'for connecting the printed circuit board 22 and a printed circuit board (not shown) on the printer frame side.

  Further, on the upper surface side of the upper case 27, exhaust passages 41a to 41d whose one ends communicate with the upper space portions of the bubble storage chambers 31a to 31d are respectively recessed (four) for each ink color. Yes. The other ends of the exhaust passages 41 a to 41 d extend across the body case 25 and communicate with the exhaust valve means 15. The exhaust passages 41 a to 41 d are defined by covering their open upper surfaces with a flexible film 43.

  Next, the exhaust valve means 15 that can exhaust the air separated in the buffer tank 14 to the outside through the exhaust passages 41a to 41d will be described with reference to FIGS.

  The casing of the exhaust valve means 15 has a series of shapes with respect to the plurality of exhaust valve means 15, and covers the lower casing 26g integrally formed on one side of the lower case 26 and the upper part of the lower casing 26g. The upper casing 27h is integrally formed by extending one side of the upper case 27. The exhaust holes 42a to 42d formed in the lower casing 26g are long in the vertical direction and open in the vertical direction, extend in parallel to each other, and are formed for each ink color (four). Each of the exhaust holes 42a to 42d has an upper large-diameter hole portion 42A and a small-diameter hole portion 42B positioned on the lower side, and these communicate with each other through the communication port 42C. The exhaust passages 41a to 41d of the upper case 27 extend to the upper casing 27h and communicate with the upper ends of the large diameter holes 42A of the exhaust holes 42a to 42d.

  The valve body 44 includes a large-diameter valve portion 44a, a small-diameter valve rod 44b integrally connected to the lower end thereof, and a ring-shaped sealing material 44c fitted (fitted) to the valve rod 44b. . The valve portion 44a has a larger diameter than the valve rod 44b, and the sealing material 44c is in contact with the valve portion 44a. The valve portion 44a faces the opening end surface 42D around the communication port 42C, which is the bottom surface of the large diameter hole portion 42A and the upper end opening portion of the small diameter hole portion 42B, through the sealing material 44c. A large-diameter valve portion 44A is inserted into the large-diameter hole portion 42A of the exhaust holes 42a to 42d, and a valve rod 44b is inserted into the small-diameter hole portion 42B leaving a gap that allows air (gas) to flow therethrough. Is done. Thereby, the valve body 44 is supported so as to be movable in the exhaust holes 42a to 42d in the exhaust passage direction (the direction in which the exhaust holes 42a to 42d that are part of the exhaust passage extend). Since the valve body 44 is pushed up by the push-up pin portion 76b (operation portion) when the valve is opened as will be described later, the lower end of the valve rod 44b extends to the vicinity of the lower end opening of the small diameter hole portion 42B. Note that rubber-like elastic packing or the like is suitable as the sealing material 44c. In this embodiment, an O-ring is used as the sealing material 44c.

  An opening end surface 42D of the communication port 42C communicating with the atmosphere serves as a valve seat surface, and a sealing material 44c is disposed between the opening end surface 42D and the valve portion 44a. Therefore, the communication port 42C is opened and closed by the valve portion 44a through the sealing material 44c.

  A coil spring 45 is fitted into the large-diameter hole portion 42A as urging means for urging the valve body 44 (valve portion 44a) in a direction to close the communication port 42C. The upper end portion of the coil spring 45 is fitted to the outside of the engaging convex portion 27b of the upper case 27, and the lower end portion is fitted into the concave portion 44aa on the upper side of the valve portion 44a. Then, the valve spring 44 (valve portion 44a) is urged by the coil spring 45 in the direction in which the sealing material 44c abuts against the opening end surface 42D, and the pushing force by the push-up pin portion 76b described later does not act on the valve body 44 The exhaust valve means 15 is in a valve closed state in which the communication port 42C is closed.

  Specifically, as shown in FIGS. 7A and 7B, the valve body 44 has a valve rod 44b with respect to a direction orthogonal to the moving direction of the valve body 44 (exhaust passage direction (extension direction of the exhaust passage)). The cut surface is configured such that five (plural) projecting surface portions 44f project radially from an intersection point 44e formed by intersecting the cut surface and the axis extending in the moving direction. The outer shape of the cut surface is rotationally symmetric with respect to the intersection 44e, and the valve rod 44b includes the same number of grooves 44d as the protruding surface 44f. The groove 44d is formed over the entire length of the valve rod 44b. Here, the number of the projecting surface portions 44f is not limited to five, and may be a rotationally symmetric shape and may be plural.

  The (five) groove portions 44d formed in the valve rod 44b function as a passage that allows an air flow between the valve rod 44b and the sealing material 44c when the valve portion 44a and the sealing material 44c are separated. .

  As shown in FIG. 6, the maintenance unit 70 includes a first cap member 71 that can seal the opening surfaces of the nozzles 16a to 16d of the recording head 11, and an exhaust port (that is, each small diameter hole portion 42B) of the exhaust valve means 15. And a second cap member 72 capable of sealing the lower end opening). These are connected together at a constant interval. Note that the cap member 72 may be configured such that the lower end opening of each exhaust valve means 15 can be individually sealed.

  Both cap members 71 and 72 are configured to move up and down by a first moving device 73A having the same structure as a known maintenance unit. A first cap member 71 that seals the nozzle surface of the recording head 11 for maintenance, and a second cap member that seals the open end of the exhaust valve means 15 (including the operation member 76 provided near the open end). 72 can be moved by one moving device 73A, and a mechanism for performing a capping operation for sealing them and a capping releasing operation for separating them is simplified.

  The moving device 73A is in the standby position when it is detected by the position detection sensor 83 that the recording head 11 (head holder 12) has moved to the standby position where recording is not performed under the control of the control means 82 described later. When the cap members 71 and 72 are raised to the first position for sealing the nozzle surface of the recording head 11 and the exhaust port of the exhaust valve means 15 respectively, and the recording head 11 is in another position (a position other than the standby position). Then, it is lowered (retracted) from the first position to a second position separated from the nozzle surface of the recording head 11 and the exhaust port of the exhaust valve means 15.

  Further, the first cap member 71 is connected to the suction pump 74 in the same manner as a known maintenance unit, and the ink and foreign matters that are thickened from the nozzles 16a to 16d are sucked and removed by driving the suction pump 74.

  As shown in FIGS. 8 and 9, the operation member 76 for operating each exhaust valve means 15 includes a plurality of push-up pins (operation parts) 76b protruding corresponding to the small diameter holes 42B of each exhaust valve means. The exhaust valve means 15 is formed so as to protrude from a base portion 76a extending in the arrangement direction, and is movably provided in the lower casing 26g. That is, the lower casing 26g is formed with a recess 26c that allows the lower end openings of the exhaust valve means 15 to communicate with each other. The base portion 76a of the operating member 76 is accommodated in the recess 26c, and the push-up pin portion 76b is connected to each small diameter hole portion 42B. It is inserted so that it can move in the direction of the exhaust passage. Each push-up pin portion 76b pushes the valve body 44 by the movement in the above direction to open the communication port 42C, thereby opening the exhaust valve means 15 to the valve open state. A gap is formed between the outer periphery of the base portion 76a of the operation member 76 and the inner periphery of the recess 26c, and between the outer periphery of each pin portion 76b and the inner periphery of the exhaust holes 42a to 42d. Each exhaust hole 42a-42d is open | released by the lower surface of the lower casing 26g. The width of the lower surface of the base portion 76a (the width in the carriage movement direction, that is, the width shown in FIG. 6) is formed larger than the diameters of the exhaust holes 42a to 42d in the same direction.

  The operation member 76 (base 76a) has a lower portion exposed from the recess 26c, but the exposed lower surface (one surface) is a nozzle surface (nozzles 16a to 16d) of the recording head 11 provided side by side. Is substantially on the same plane as the surface of the opening. Since they are substantially on the same surface, it is easy to continuously clean (wipe) the nozzle surface and the lower surface of the operation member 76, and the problem of interference with the paper P when the head holder 12 is moved is Does not occur.

  Further, an engaging portion 76c that protrudes in parallel with the push-up pin portion 76b is provided at the center of the operation member 76. On the other hand, a guide hole portion 26a is provided in the lower casing 26g in parallel with the central axis of the exhaust holes 42a to 42d. The engaging portion 76c is slidably engaged with the guide hole 26a with a gap through which air can flow, and the operating member 76 is moved while being guided in the exhaust passage direction due to the engaging relationship. Since the large-diameter head portion of the engaging portion 76c contacts the outer edge of the upper end opening of the guide hole portion 26a, the operation member 76 is held by the lower casing 26g. Will move together. That is, the operation member 76 is built in the lower part of the lower casing 26g.

  At the upper end of the guide hole portion 26a, an air communication hole 26b communicating with the atmosphere (outside air) is formed. During exhaust purging, the guide hole portion 26a is sealed by a closing portion 76d provided on the operation member 76 and extending further upward than the push-up pin portion 76b. The atmosphere communication hole 26b is closed via the portion 76e (see FIG. 9).

  The operation member 76 (push-up pin portion 76b) is configured to move up and down by a movable member 73a of the valve opening / closing means 73B (second moving means). The movable member 73a penetrates the bottom portion of the second cap member 72 and is supported so as to be vertically slidable. By pushing (pushing up) the substantially central portion of the operation member 76, the operation member 76 is moved without being inclined.

  Then, the recording head 11 moves to a standby position where recording is not performed, the cap members 71 and 72 are raised, the cap member 71 seals the nozzle surface of the recording head 11, and the cap member 72 surrounds the recess 26c. When closely contacting the lower surface of the lower casing 26g, that is, when the exhaust port of the exhaust valve means 15 is sealed, the valve rod 44b is pushed upward by the push-up pin portion 76b of the operation member 76 by the second moving means 73B. At this time, as shown in FIG. 9, the sealing member 44c moves together with the valve portion 44a, and the exhaust holes 42a to 42d are in communication with each other through the groove portion 44d, that is, the communication port 42C is opened and the valve is opened. . In this valve open state, the bubbles in the bubble storage chambers 31a to 31d can be exhausted from the exhaust passages 41a to 41d to the atmosphere via the exhaust holes 42a to 42d, the second cap member 72, and the suction pump 74. For example, when ink adheres between the opening end surface 42D with which the sealing material 44c contacts and the sealing material 44c, only the valve rod 44b rises when the valve is opened, and the sealing material 44c remains on the opening end surface 42D. Even if such a phenomenon occurs, exhaust is possible because the communication port 42C is opened through the groove 44d as described above. Therefore, bubbles (air) do not continue to accumulate in the bubble storage chambers 31a to 31d, and the bubbles (air) do not move toward the recording head 11, so that normal recording (printing) is hindered. There is nothing. Incidentally, in order to prevent a problem such as the ink remaining around the sealing material 44c (O-ring) thickening and the exhaust valve means 15 not opening, the lower end opening of the exhaust valve means 15 is always capped at the standby position. This can be avoided. Further, it is possible to achieve both the prevention of drying and the suction by making the atmosphere communication hole 26b into a maze shape.

  The second cap member 72 is connected to the suction pump 74 through a flow path common to the first cap member 71. Then, with the exhaust port of the exhaust valve means 15 sealed, the bubbles accumulated in each of the bubble storage chambers 31a to 31d can be collectively sucked and discharged to the atmosphere by driving the suction pump 74.

  As described above, the ink supplied from the ink tank to the recording head 11 through the ink supply tubes 13a to 13d is temporarily stored in the bubble storage chambers 31a to 31d in the middle of the ink flow path, whereby bubbles are generated from the ink. Are separated and floated, and the bubbles accumulated in the upper portions of the bubble storage chambers 31 a to 31 d can be discharged by the suction pump 74.

  The first cap member 71 and the second cap member 72 are alternatively connected to the suction pump 74 by the switching valve 75. The first cap member 71 and the second cap member 72 simultaneously seal the nozzle surface of the recording head 11 and the exhaust port of the exhaust valve means 15 by the operation of the moving device 73A, and maintenance is performed. A desirable maintenance procedure is as follows. First, the air bubbles accumulated in the upper portions of the air bubble storage chambers 31 a to 31 d are discharged through the second cap member 72, and then the ink is sucked and removed from the nozzles 16 a to 16 d through the first cap member 71. Here, the bubbles are discharged by the second cap member 72. If the bubbles in the bubble storage chambers 31a to 31d are discharged from the recording head 11 side only by the first cap member 71, a large amount of ink is discharged. This is because, as described above, it is possible to discharge the bubbles and recover the recording head with a small ink discharge amount.

  The maintenance not only sequentially discharges the bubbles in the bubble storage chambers 31a to 31d and sucks the ink from the nozzles 16a to 16d, but also only sucks the ink from the nozzles 16a to 16d or the bubbles in the bubble storage chambers 31a to 31d. It is also possible to discharge each of them alone.

  The above-described control of the exhaust operation is performed by control means connected to the maintenance unit 70 (first moving means 73A, second moving means (valve opening / closing means) 73B, suction pump 74, switching valve 75, and position detection sensor 83). 82 (see FIG. 6). That is, when the position detection sensor 83 detects that the recording head 11 has moved to the standby position, the cap member 72 is moved to the first position (together with the cap member 71) by the first moving means 73A. At the same time, the operating member 76 is moved in the exhaust passage direction by the second moving means 73B, the valve body 44 is moved in the opening direction, and the four exhaust valve means 15 are simultaneously opened. At the same time, the air communication hole 26b is also closed by the closing portion 76d. In this state, the suction pump 74 is driven to perform a first exhaust operation for exhausting the air separated in the buffer tank 14 to the outside through the exhaust passages 41a to 41d. After the end of the first suction operation, the movable member 73a is lowered, the operation member 76 is lowered by gravity or the coil spring 45, and each exhaust valve means 15 is closed to shut off the communication between the buffer tank 14 and the outside. Then, a second exhaust operation is performed to exhaust the inside of the exhaust valve means 15 (specifically, the downstream side of the communication port 42C) and the inside of the recess 26c together with the atmosphere introduced from the outside through the atmosphere communication hole 26b. As a result, the ink remaining around the communication port 42C, the small-diameter hole 42B, the operation member 76, and the like is sucked together with the atmosphere. Thereafter, the switching valve 75 is switched to perform a suction operation through the nozzle surface of the recording head 11, and although not shown, a known wiping member (wiper blade) causes the nozzle surface, the lower surface of the operation member 76, and the operation member 76 thereof. The lower surface of the lower casing 26g around the lower surface is wiped away, and the ink is removed.

  When the recording head 11 is in a position other than the standby position and recording is performed normally, the exhaust valve means 15 is in a valve closed state. At this time, ink does not remain inside the exhaust valve means and around the operation member 76 as described above, so that it does not fall during recording.

  In addition to the above embodiment, the present invention can be configured as follows.

  (i) In the above embodiment, the case where the valve body 44 of the exhaust valve means 15 moves in the vertical direction has been described. However, the movement direction of the valve body is not limited to the vertical direction, and other directions other than the vertical direction It can also be.

  (ii) It is not always necessary to provide the atmosphere communication hole 26b in order to introduce the atmosphere from the outside during the second exhaust operation. For example, as shown in FIG. 10, after the first exhaust operation, the second cap member is provided. 72 is lowered from the lower surface of the lower casing 26g to a position where the minute gap S is opened, and the second exhaust operation is performed. That is, it is also possible to adopt a configuration in which the ink remaining in the communication port 24C and the recess 26c is removed while the air is sucked through the minute interval S. The engaging portion 76c ′ of the operation member 76 ′ is provided with a through hole 76ca, and after the second cap member 72 is separated from the lower surface of the lower casing 26g and before performing the second exhaust operation. The operation member 76 ′ can be easily lowered by the atmospheric pressure acting on the upper side of the operation member 76 ′ through the through hole 76ca.

  (iii) The engaging portion (guide portion) of the operating member 76 is provided at the center of the operating member 76, and as shown in FIG. 11, the engaging portions 76c '' are symmetrically arranged at both ends of the operating member 76 ''. It can also be slidably engaged with the guide hole 26a ″. In this case, although not shown, similarly to the configuration shown in FIG. 8, a blocking portion 76 b facing the atmosphere communication hole 26 b ″ is provided, and when the exhaust valve means 15 is opened, the atmosphere communication hole is closed. Further, each push-up pin portion 76b '' of the operation member 76 '' is formed to have a size that can slide along the inner periphery of the small-diameter hole portion 42B. Can move up and down without tilting. In this case, the cross-sectional shape of the push-up pin portion 76b '' is the same as the cross-sectional shape of the bubble rod 44b in order to secure an exhaust passage between each push-up pin portion 76b '' and the inner periphery of the small diameter hole portion 42B. Has a groove on the outer periphery.

  (iv) It is not necessary to open and close all the exhaust valve means with one operating member. For example, as shown in FIG. 12, one operating member 76 ′ ″ has some exhaust valve means (on the left side in FIG. Three exhaust valve means) are provided only for the remaining exhaust valve means (one exhaust valve means on the right side in FIG. 12), and another operation member 82 is provided, and the operation member 76 '' ' The operating member 82 can be configured to be operated independently by different moving means 73a and 84, respectively. In the case of FIG. 12, the ink supply tube, the bubble storage chamber, and the exhaust passage for black ink, which consumes a large amount of ink, are set to have a smaller channel resistance than that for ink of other colors that consume less. The exhaust valve means are divided into two groups so that the exhaust can be performed in an optimum manner corresponding to the difference in flow path resistance, and the exhaust is performed separately. Here, in the cap member 72 ′, the part that seals the part of the exhaust valve means and the part that seals the remaining part of the exhaust valve means are partitioned by the partition part 72 a, and any part is selected by the switching valve 81. By connecting to a suction pump, the exhaust can be performed individually and independently. The engaging member 76c ′ ″ is slidably engaged with the guide hole 26a ′ ″, and the operating member 76 ′ ″ is operably accommodated in the recess 26c ′ ″ of the lower case. The point is the same as the above-described embodiment. Although not shown, the operation member 82 has an engagement portion similar to the operation member 76 at both ends in the direction orthogonal to the paper surface of FIG. 12, and is slidably engaged with and supported by the guide hole portion.

  (v) Instead of the suction operation of the suction pump 74, a positive pressure is applied to the ink from the ink tank side to suck and remove the thickened ink and foreign matters from the nozzles 16a to 16d, and the bubble storage chambers 31a to 31d. Bubbles can also be discharged. Alternatively, the suction operation and the positive pressure application to the ink can be used in combination.

It is a schematic block diagram which shows the main components of the inkjet printer which concerns on this invention. It is a bottom view of an inkjet printer head. FIG. 3 is an exploded perspective view of a recording head, a reinforcing frame, a head holder, and a buffer tank. 1 is a plan view partially showing a cross section of an inkjet printer head according to the present invention. It is sectional drawing in the VV line of FIG. It is sectional drawing in the VI-VI line of FIG. (A) (b) shows embodiment of a valve body, respectively, (a) is a partial cross section front view, (b) is a bottom view. It is sectional drawing in the VIII-VIII line of FIG. It is operation | movement explanatory drawing. It is a figure similar to FIG. 9 which shows another embodiment. It is a figure similar to FIG. 8 which shows another embodiment. It is a figure similar to FIG. 8 which shows embodiment about a modification.

Explanation of symbols

P Paper 100 Inkjet printer 11 Recording head 12 Head holder 14 Buffer tank 15 Exhaust valve means 16a to 16d Nozzle 26a Guide hole 26b Air communication hole 26c Recess 26g Lower casing 31a to 31d Bubble storage chamber (reservoir)
41a-41d Exhaust passage 42a-42d Exhaust hole 44 Valve body 71 1st cap member 72 2nd cap member 73A 1st moving device 73a Movable member 73B 2nd moving device 76 Operation member 76a Base part 76b Push-up pin part ( Operation part)
76c engaging part 84 operation member

Claims (8)

A recording head that ejects ink from nozzles to record on a recording medium; an ink tank that stores ink supplied to the recording head; an ink flow path that supplies ink from the ink tank to the recording head; and An ink jet printer comprising: a buffer tank for storing ink supplied through an ink flow path; and an exhaust valve means capable of exhausting air separated in the buffer tank to the outside through an exhaust passage,
A first exhaust operation for sealing the exhaust port of the exhaust valve means with a cap member and opening the exhaust valve means in a valve open state to exhaust the air separated in the buffer tank to the outside through the exhaust passage;
A second exhaust operation that maintains the exhaust port of the exhaust valve means by the cap member and closes the exhaust valve means to exhaust the inside of the exhaust valve means together with the air introduced from the outside; An inkjet printer characterized by comprising: A recording head that ejects ink from nozzles to record on a recording medium; an ink tank that stores ink supplied to the recording head; an ink flow path that supplies ink from the ink tank to the recording head; and In an inkjet printer comprising: a buffer tank that stores ink supplied through an ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage.
A maintenance unit that seals the exhaust port of the exhaust valve means with a cap member and opens the exhaust valve means to release the air separated in the buffer tank to the outside through the exhaust passage;
Control means for controlling the maintenance unit to exhaust the air separated in the buffer tank and then closing the exhaust valve means to exhaust the inside of the exhaust valve means together with the air introduced from the outside; An ink jet printer comprising: A recording head that ejects ink from nozzles to record on a recording medium; an ink tank that stores ink supplied to the recording head; an ink flow path that supplies ink from the ink tank to the recording head; and In an inkjet printer comprising: a buffer tank that stores ink supplied through an ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage.
Valve opening and closing means for opening and closing the exhaust valve means;
A cap member capable of sealing the exhaust port of the exhaust valve means;
First moving means for moving the cap member between a first position for sealing the exhaust port of the exhaust valve means and a second position spaced from the exhaust port of the exhaust valve means;
A suction pump connected to the cap member;
When the recording head is connected to the valve opening / closing means, the first moving means, and the suction pump and moves to a standby position where recording is not performed, the cap member is moved to the first position, and the exhaust valve means is operated as a valve. A first exhaust operation for exhausting the air separated in the buffer tank in an open state to the outside through an exhaust passage, and exhausting the interior of the exhaust valve means together with the air introduced from the outside with the exhaust valve means in a closed state An ink jet printer comprising: a control unit that performs a second exhaust operation. The buffer tank has a reservoir for each of a plurality of types of ink,
The exhaust passage and the exhaust valve means exist for each of the reservoirs,
The exhaust valve means is opened and closed by movement of the valve body in the exhaust passage direction, and is locked to a casing of the exhaust valve means so as to be movable in the exhaust passage direction. An operation member having a plurality of corresponding operation units is provided,
The exhaust valve means includes a second moving means having a movable member and moving the operation member in the direction by the movable member, and the cap member is more exhausted than the operation member at the first position. 4. The ink jet printer according to claim 3, wherein the ink jet printer is located on a downstream side of the passage, and the second exhausting operation exhausts the surroundings of the operation member. 5.   A guide hole portion is provided in the casing of the exhaust valve means, and an engaging portion is provided in the operation member to be slidably engaged with the guide hole portion, and the guide hole portion is provided with the guide hole portion during the first exhaust operation. The inkjet printer according to claim 4, further comprising an air communication hole that is closed. The operating member is provided only for some exhaust valve means,
6. The ink jet printer according to claim 4, wherein another operation member having an operation portion corresponding to the valve body is provided for the remaining exhaust valve means.   7. The ink jet printer according to claim 5, wherein the engaging portion of the operation member is disposed at a center of the operation portion member. A recording head that ejects ink from nozzles to record on a recording medium; an ink tank that stores ink supplied to the recording head; an ink flow path that supplies ink from the ink tank to the recording head; and In an inkjet printer comprising: a buffer tank that stores ink supplied through an ink flow path; and an exhaust valve means that can exhaust the air separated in the buffer tank to the outside through an exhaust passage.
Valve opening and closing means for opening and closing the exhaust valve means;
A cap member capable of sealing the exhaust port of the exhaust valve means;
First moving means for moving the cap member between a first position for sealing the exhaust port of the exhaust valve means and a second position spaced from the exhaust port of the exhaust valve means;
A suction pump connected to the cap member;
When the recording head is connected to the valve opening / closing means, the first moving means, and the suction pump and moves to a standby position where recording is not performed, the cap member is moved to the first position, and the exhaust valve means is operated as a valve. A first exhaust operation in which the air separated in the buffer tank in an open state is exhausted to the outside through an exhaust passage; and the atmosphere introduced from the outside with the cap member positioned slightly away from the exhaust port of the exhaust valve means And an ink jet printer comprising a control means for performing a second exhaust operation for exhausting the inside of the exhaust valve means.

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