JP6520316B2 - Liquid discharge device - Google Patents

Description

  The present invention relates to a liquid discharge device.

  As a conventional liquid discharge apparatus, for example, a fluid discharge apparatus shown in Patent Document 1 has been proposed. In this fluid discharge device, a nozzle hole and a lip are provided on the lower surface of the head. The protrusion of the lip protrudes from the base of the lip toward the platen, and is disposed in a rectangular shape so as to surround the nozzle hole. When the lower surface of the head is capped by the platen, the projection abuts on the platen and the platen covers the lower surface of the head.

JP 2012-45778 A

  In the fluid discharge device of Patent Document 1, when the protrusion is brought into contact with the platen, liquid tends to be accumulated between the protrusion and the platen due to capillary action. In particular, the outside of the projection is exposed to the outside air, whereby the liquid accumulated on the outside of the projection is dried to form a fillet in which the liquid is solidified. Also, the larger the distance between the base of the lip and the platen, the larger the fillet size formed at this distance. When such a large fillet is pinched between the projection and the platen, a gap is created between the projection and the platen. Therefore, at the time of liquid purge, air enters from the gap, which causes a problem that the liquid of the nozzle can not be sufficiently discharged.

  The present invention has been made to solve such a problem, and it is an object of the present invention to provide a liquid discharge apparatus capable of suppressing a defect due to a fillet formed at a contact portion between a cap and an exhaust surface. There is.

  A liquid discharge apparatus according to an aspect of the present invention includes a head having a nozzle for discharging liquid, a liquid flow path for supplying liquid to the head, and a gas storage chamber for storing gas in the liquid flow path. A head unit having an exhaust flow path for discharging the gas in the gas storage chamber, and an exhaust surface having an opening formed at a downstream end of the exhaust flow path; and the exhaust so as to surround the opening. And a cap having a cap surface that covers the exhaust surface so as to include the opening and that can come into contact with the projection, the cap surface being flexible so that the cap surface is flexible. The outer edge of the cap surface protrudes further outward from the protrusion than the outer edge of the exhaust surface when in the capping state in which the protrusion is in contact with the cap surface and is more easily deformed than the protrusion. The capping state When the cap surface is in contact with the convex portion, the cap surface of the portion extending from the abutting portion of the cap surface to the outer edge of the cap surface is parallel to the exhaust surface, and the exhaust surface is closer to the liquid than the cap surface. High affinity.

  According to this, the cap surface has flexibility and is more easily deformed than the convex portion. Therefore, in the capping state in which the convex portion abuts on the cap surface, the cap surface is deformed by the convex portion, and the convex portion is buried in the cap surface. Thus, the liquid between the projection and the cap surface is pushed out by the projection. In addition, in the capping state, the outer edge of the cap surface protrudes to the outside farther from the protrusion than the outer edge of the exhaust surface. For this reason, the liquid pushed out from the convex portion flows on the cap surface between the outer edge of the protruding cap surface and the outer edge of the exhaust surface. In addition, in the capping state, the cap surface of the portion from the contact portion of the cap surface in contact with the convex portion to the outer edge of the cap surface is parallel to the exhaust surface. Therefore, even if a fillet is formed by drying of the liquid flowing to the outer edge side of the cap surface, the fillet does not protrude high from the exhaust surface to the cap surface side. Therefore, the leak between the exhaust surface and the cap surface due to the fillet can be prevented, and the purge for exhausting the gas from the exhaust channel can be sufficiently performed. Furthermore, the exhaust surface has a higher affinity for liquid than the cap surface. Thereby, since the liquid and the fillet adhere to the exhaust surface, the liquid and the fillet can be removed by a wiper member or the like.

  The present invention has an effect that it is possible to provide a liquid discharge apparatus having the configuration described above and capable of suppressing a defect due to a fillet formed at a contact portion between a cap and an exhaust surface.

  The above object, other objects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments with reference to the attached drawings.

FIG. 2 is a view schematically showing a liquid discharge device according to Embodiment 1 of the present invention. It is a block diagram which shows the functional structure of the liquid discharge apparatus of FIG. It is a figure which shows the head surface of FIG. 2 schematically. It is sectional drawing which shows the head unit and cap of FIG. 3 roughly. FIG. 4 is a cross-sectional view schematically showing the head and the exhaust cap of FIG. 3; FIG. 6A is a view schematically showing a capping state in which a convex portion is in contact with a cap surface, FIG. 6B is a view schematically showing a state in which gas is discharged from an exhaust flow path, and FIG. FIG. 6D is a view schematically showing a state in which a cap surface is separated from an exhaust surface, and FIG. 6D is a view schematically showing a capping state. FIG. 7 is a cross-sectional view schematically showing a head of a liquid discharge device according to Embodiment 2 of the present invention. It is a figure which shows roughly the head surface of the liquid discharge apparatus based on Embodiment 3 of this invention. FIG. 14 is a view schematically showing an exhaust cap of a liquid discharge device according to Embodiment 4 of the present invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings, and the redundant description thereof will be omitted.

Embodiment 1
First, the functional configuration of the liquid ejection device 10 will be described with reference to FIGS. 1 and 2. FIG. 1 is a view schematically showing a liquid ejection device 10 according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a functional configuration of the liquid discharge device 10. As shown in FIG. In addition, although the printer which discharges an ink is demonstrated as an example of the liquid discharge apparatus 10 below, if it is the liquid discharge apparatus 10 which discharges a liquid, the liquid discharge apparatus 10 is not limited to a printer.
The liquid ejection device 10 is a device that ejects a liquid. This liquid is composed of a solvent and a solute, and examples thereof include pigment ink and dye ink. The solute includes, for example, not only those dissolved in the solvent such as dyes but also those dispersed in the solvent such as pigments. The liquid ejection device 10 includes a head unit 20, a maintenance unit 30, and a control unit 40. The liquid ejection device 10 may further include a paper feed mechanism 11, a platen 12, and a transport mechanism 14. The head unit 20 has a head 21 and a carriage 22 for holding and transporting the head 21.

  The sheet feeding mechanism 11 is a mechanism for feeding the sheet 19 in a sheet feeding tray (not shown) to the conveyance path. The platen 12 is a table on which the supplied paper 19 is placed.

  The carriage 22 is a transport unit that reciprocates the head 21 in the scanning direction. For example, the carriage 22 is supported by two guide rails 122 extending in the scanning direction, and reciprocates along the guide rails 122 in the scanning direction. The carriage 22 moves across an area facing the platen 12 (recording area) and an area adjacent to the storage area (maintenance area) along the scanning direction. In the storage area, the carriage 22 is spaced above and in parallel with the platen 12.

For example, four sub tanks 125 are mounted on the carriage 22. The sub-tanks 125 are arranged side by side along the scanning direction and connected to the tube joint 125a. The sub tank 125 is connected to the ink cartridge 125c by a flexible tube 125b via a tube joint 125a. For example, four colors of ink of magenta, cyan, yellow, and black are stored in the four ink cartridges 125c, respectively.
Further, an exhaust unit 126 for exhausting air remaining in the sub tank 125 is connected to the sub tank 125. The details of the exhaust unit 126 will be described later.

The head 21 is a portion for discharging a liquid such as ink from the nozzle holes of the nozzles 25 and is attached to the lower part of the carriage 22 so that the nozzle holes face the platen 12 in the storage area. The plurality of nozzles 25 are arranged in the transport direction orthogonal to the scanning direction to form a nozzle row. For example, the four nozzle rows are arranged in the scanning direction. The transport mechanism 14 transports the sheet 19 supplied from the sheet feed tray to the sheet discharge tray (not shown) through the space between the platen 12 and the head 21. The transport direction is orthogonal to the scanning direction. For example, two transport rollers 114 are used as the transport mechanism 14. The two conveyance rollers 114 are disposed upstream and downstream of the carriage 22 in the conveyance direction, and rotate in the conveyance direction with the scanning direction as an axial direction.

  The maintenance unit 30 is a unit that performs various maintenance operations for maintaining and recovering the liquid discharge performance from the nozzle holes of the head 21, and is disposed in the maintenance area. The maintenance unit 30 has an exhaust cap 31, a contact / separation part 32, a pressure adjustment part 33, an exhaust valve 34 and a wiper member 35. These will be described later. The maintenance unit 30 may also have a waste liquid tank 30a.

  The control unit 40 includes an operation unit (not shown) and a storage unit (not shown). The operation unit is configured by a processor or the like, and the storage unit is configured by a memory accessible by the operation unit. Each unit of the liquid ejection device 10 is controlled by the calculation unit executing the program stored in the storage unit.

  Next, the recording (printing) operation of the liquid ejection device 10 will be described with reference to FIGS. 1 and 2. This operation is performed by the control unit 40. At the time of printing, the sheet 19 is supplied from the sheet feeding tray by the sheet feeding mechanism 11, placed on the platen 12, and further intermittently conveyed in the conveyance direction by the conveyance mechanism 14. The head 21 discharges the liquid from the nozzle hole while moving in the scanning direction by the carriage 22. A desired image, characters, etc. are printed on the paper 19 by this liquid.

  Next, the configuration of the head unit 20 will be described with reference to FIGS. 1 and 3 to 5. FIG. 3 is a cross-sectional view schematically showing the head surface of the head unit 20. As shown in FIG. FIG. 4 is a cross-sectional view schematically showing the head unit 20 and the exhaust cap 31 cut in the scanning direction. FIG. 5 is a cross-sectional view schematically showing the head unit 20 and the exhaust cap 31 cut in the transport direction.

As shown in FIG. 4, the internal space of the sub tank 125 is used as an ink storage chamber 124. The ink storage chamber 124 communicates with the ink cartridge 125c (FIG. 1) through a flexible tube 125b connected to the tube joint 125a (FIG. 1). Thus, the ink is stored in the ink storage chamber 124.
An ink supply hole 125d is formed at the bottom of the sub tank 125, and the ink storage chamber 124 is in communication with the nozzle 25 (FIG. 3) of the head 21 through the ink supply hole 125d. Thus, the ink in the ink storage chamber 124 is temporarily stored in the ink storage chamber 124 and then supplied to the head 21 from the ink supply hole 125 d.

  At the upper part of the ink storage chamber 124, air mixed in the liquid flow path is retained. This liquid flow path is a flow path for supplying the liquid to the head 21 and is composed of the flexible tube 125 b and the ink storage chamber 124 of the sub tank 125. Then, the ink storage chamber 124 is used as a gas storage chamber for storing the gas in the liquid flow channel.

  An exhaust port 125 e is formed in the upper portion of the sub tank 125, and the ink storage chamber 124 communicates with the exhaust flow path 26 of the exhaust unit 126 through the exhaust port 125 e. The details of the exhaust unit 126 will be described later.

  As shown in FIGS. 3 to 5, for example, the head 21 has a substantially rectangular shape. The head 21 is provided with a large number of nozzles 25. The nozzle 25 is a flow path through which the liquid flows, and is connected to a flow path (liquid flow path) 125 which supplies the liquid to the head 21. The head 21 has its lower surface (head surface), and the head surface is constituted by the nozzle surface 23.

  The nozzle surface 23 is, for example, a rectangular flat surface. An opening (nozzle hole) located at the downstream end of the nozzle 25 is formed in the nozzle surface 23. The nozzle surface 23 has a property of repelling liquid since its surface tension is lower than that of the liquid and its wettability is low. For example, the nozzle surface 23 is a smooth surface having a small surface roughness, and is formed of polyimide. The nozzle surface 23 may be water-repellent coated.

  The carriage 22 is provided with a plurality of exhaust flow paths 26. The exhaust flow path 26 is a flow path for discharging the gas in the liquid of the liquid flow path (flexible tube 125 b, ink storage chamber 124). An exhaust surface 24 is provided on the lower surface of the carriage 22. However, the exhaust flow path 26 may be provided not on the carriage 22 but on another component (not shown) in the head unit 20. In this case, the lower surface of the other component is the exhaust surface 24 of the exhaust unit 126.

  The exhaust surface 24 is, for example, a rectangular flat surface. An opening (exhaust hole) located at the downstream end of the exhaust flow passage 26 is formed in the exhaust surface 24. The exhaust surface 24 has the property of having a higher affinity to the liquid than the surface (cap surface) 31 c of the exhaust cap 31 that can contact the exhaust surface 24. The exhaust surface 24 is formed on the carriage 22. When wiping of the nozzle surface 23 is started by the wiper member 35 (FIG. 1), the wiper member 35 contacts the left side surface of the carriage 22 and the liquid remaining in the wiper member 35 adheres to the left side surface of the carriage 22. The carriage 22 is formed of a material having high affinity to the liquid 19 so that the attached liquid does not fall on the sheet 19 when printing on the sheet 19 (FIG. 1). For example, the exhaust surface 24 is formed of a material and surface roughness such that the surface tension is lower than that of the cap surface 31 c. For example, the exhaust cap 31 is formed of silicon rubber so as to reduce the sliding load with the shaft 36b (FIG. 4) described later, while the exhaust surface 24 is made of ABS / PBT resin filled with glass fiber, etc. It is formed of Further, the surface roughness of the exhaust surface 24 is formed to be rougher than the cap surface 31 c of the exhaust cap 31.

  The exhaust surface 24 is provided on the same plane as the nozzle surface 23 and is adjacent to the nozzle surface 23 in the scanning direction. The head unit 20 is provided with a first groove 27 between the exhaust surface 24 and the nozzle surface 23. The area of the exhaust surface 24 is smaller than that of the nozzle surface 23, and a convex portion 28 is provided on the exhaust surface 24.

  The convex portion 28 is a protrusion for pushing out the liquid remaining between the exhaust surface 24 and the cap surface 31 c to enhance the adhesion between the exhaust surface 24 and the cap surface 31 c, and protrudes from the exhaust surface 24 . The convex portion 28 is a single rectangular or substantially rectangular ring extending continuously in the transport direction and the scanning direction on the exhaust surface 24. The convex portion 28 is disposed on the exhaust surface 24 outside the exhaust hole so as to surround all the exhaust holes.

  The convex portion 28 has an inner surface, an outer surface and a lower end surface. The lower end surface is formed of a curved surface that curves between the inner and outer surfaces. The protruding height of the convex portion 28 is appropriately set. For example, when the convex portion 28 is too high, the liquid accumulated at the corner between the exhaust surface 24 and the convex portion 28 can not be wiped off by the wiper member 35 (FIG. 1). On the other hand, if the convex portion 28 is too low, the liquid can not be pushed out by the convex portion 28 and adhesion can not be improved. Therefore, the height of the convex portion 28 is appropriately set in accordance with the amount of deformation of the wiper member 35 and the amount of the liquid to be pushed out.

  The first groove 27 is an elongated recess for releasing the liquid pushed outward by the convex portion 28 and is recessed from both the nozzle surface 23 and the exhaust surface 24. The first grooves 27 extend linearly in the transport direction so as to extend over the entire length of the exhaust surface 24 in the transport direction. The edge on the exhaust surface 24 side of the first groove 27 is the outer edge of the exhaust surface 24. The width in the scanning direction of the first groove 27 is set larger than the distance in the scanning direction between the outer edge of the cap surface 31 c and the outer edge of the exhaust surface 24 in the capping state. That is, the width of the first groove 27 is set such that the outer edge of the cap surface 31 c is positioned in the first groove 27 in the capping state. Therefore, in the capping state, the outer edge of the cap surface 31 c is located between the edge on the exhaust surface 24 side of the first groove 27 and the edge on the nozzle surface 23 side.

  The depth of the first groove 27 is not particularly limited. However, if the first groove 27 is too deep, the wiper member 35 can not wipe the liquid in the first groove 27, and the liquid remains in the first groove 27. On the other hand, if the first groove 27 is too shallow, the liquid pushed out by the convex portion 28 can not be released. Therefore, the depth of the first groove 27 is appropriately set in accordance with the amount of deformation of the wiper member 35 and the amount of the liquid pushed out.

  The wall surface 24 a is a surface that is continuous with the portion of the exhaust surface 24 outside the convex portion 28 and extends in the direction orthogonal to the exhaust surface 24 in the direction opposite to the direction in which the convex portion 28 protrudes from the outer edge of the exhaust surface 24. . The wall surface 24 a has a property that the affinity to the liquid is higher than the cap surface 31 c of the exhaust cap 31. For example, four wall surfaces 24 a are provided for the rectangular exhaust surface 24. That is, the outer edge of the rectangular exhaust surface 24 is constituted by two short sides extending linearly in the scanning direction and two long sides extending linearly in the transport direction. The side surface of the head 21 extending upward from the short side of the outer edge corresponds to the wall surface 24 a. Further, the side surface of the head 21 extending upward from the long side far from the nozzle surface 23 of the two long sides corresponds to the wall surface 24 a. Furthermore, the inner surface of the first groove 27 extending upward from the long side closer to the nozzle surface 23 corresponds to the wall surface 24 a. Thus, the wall surface 24 a is configured by the side surfaces of the three heads 21 and the inner surface of one first groove 27. Thus, the exhaust surface 24 is surrounded by the wall surface 24 a extending upward from the outer edge of the exhaust surface 24. In the capping state, the wall surface 24a is located between the convex portion 28 and the outer edge of the cap surface 31c.

  The nozzle 25 is constituted of, for example, three color ink nozzles 25c, 25m, 25y and a black ink nozzle 25b. As nozzles 25 for three color inks, a nozzle 25c for cyan ink, a nozzle 25m for magenta ink, and a nozzle 25y for yellow ink are exemplified. The nozzles 25 are arranged in the scanning direction from the side of the exhaust flow path 26 in the order of a cyan ink nozzle 25c, a magenta ink nozzle 25m, a yellow ink nozzle 25y, and a black ink nozzle 25b. Also, the ink nozzles 25c, 25m, 25y, 25b of the same color are arranged in the transport direction. The upstream end of the nozzle 25 is connected to the ink cartridge 125c (FIG. 1) via a liquid flow path (flexible tube 125b, ink storage chamber 124). The pitch and the number of the nozzles 25 in the transport direction are appropriately set in accordance with the specifications such as the resolution of the image required of the liquid ejection device 10. Also, the number of rows of nozzles 25 in the scanning direction may be increased or decreased according to the number of colors of the color ink.

  In the present embodiment, four exhaust flow paths 26 are provided and arranged in the transport direction. As shown in FIG. 4, the upstream end of the exhaust flow path 26 is connected to the ink storage chamber 124 via the exhaust port 125 e of the sub tank 125. The exhaust passage 26 for black ink, the exhaust passage 26 for yellow ink, the exhaust passage 26 for magenta ink, and cyan ink so that the exhaust passage 26 for black ink is on the downstream side in the transport direction The exhaust flow paths 26 are arranged in this order in the transport direction.

  The exhaust flow path 26 is configured of an upper flow path, a central flow path, and a lower flow path. In the direction orthogonal to the up and down direction, the area of the central flow passage is larger than the upper and lower flow passages. For this reason, the central flow path is provided with an upper surface and a lower surface, the upper surface is provided with an opening to which the upper flow channel is connected, and the lower surface is provided with an opening to which the lower flow channel is connected. A valve (exhaust valve) 34 for opening and closing the exhaust channel 26 is provided in the space in the central channel.

  The exhaust valve 34 is provided in the vicinity of the opening (exhaust hole) of the exhaust flow path 26 and always closes the exhaust flow path 26. For example, the exhaust valve 34 is constituted by a valve body 34a, an O ring 34b and a spring 34c There is. The valve body 34 a has, for example, a disk shape, and is provided movably in the vertical direction in the exhaust passage 26. A rod 34d is connected to the lower surface of the valve body 34a. The rod 34d is a rod-like member, and extends in the vertical direction in the lower channel.

  The O-ring 34 b is a seal member that seals the exhaust flow path 26 and is provided to surround the opening of the lower surface of the central flow path. The spring 34c is a member that biases the valve body 34a downward, and is disposed between the upper surface of the central flow passage and the upper surface of the valve body 34a.

  When the valve body 34a is pushed downward by the spring 34c, the valve body 34a is pressed against the lower surface of the central flow path via the O ring 34b, and the O ring 34b is formed on the lower surface of the valve body 34a and the lower surface of the central flow path Fill the gap between Thereby, the gas does not flow between the central flow passage and the lower flow passage through the opening of the lower surface of the central flow passage, and the exhaust valve 34 closes the exhaust flow passage 26. On the other hand, when the rod 34d is pushed up by a shaft 36b described later, the valve body 34a ascends and separates from the O-ring 34b. As a result, gas flows between the central flow passage and the lower flow passage through the opening of the lower surface of the central flow passage, and the exhaust valve 34 opens the exhaust flow passage 26.

  Next, the configuration of the maintenance unit 30 will be described with reference to FIG. The exhaust cap 31 is a cap for covering the exhaust surface 24, and is formed of, for example, elastic silicone rubber or the like so as to be easily in close contact with the exhaust surface 24. The exhaust cap 31 is box-shaped and has a bottom 31a and a side 31b. A recess is formed by the inner surface of the bottom surface portion 31 a and the inner surface of the side surface portion 31 b, and a space (internal space) surrounded by the recess is provided inside the exhaust cap 31. The recess has an opening that opens upward, whereby the internal space is an open space that opens upward.

  When the exhaust surface 24 of the head unit 20 is above the exhaust cap 31 in the maintenance area, the bottom surface 31 a of the exhaust cap 31 can face the exhaust surface 24. At this time, the side surface portion 31b is erected on the exhaust surface 24 side from the bottom surface portion 31a. The size of the opening of the recess is set such that the upper surface of the side surface portion 31b surrounds the entire exhaust hole. Thus, the exhaust cap 31 can cover the exhaust surface 24 so as to include the exhaust hole of the head unit 20.

  The bottom surface portion 31a has a rectangular plate shape, and for example, four insertion holes 31d and one suction hole 31e are provided to penetrate the bottom surface portion 31a. The insertion holes 31 d and the suction holes 31 e are arranged in the transport direction.

  The side surface portion 31 b has a plate shape rising from the rectangular peripheral portion of the bottom surface portion 31 a. The upper end surface is flat and has a rectangular inner edge and an outer edge. The upper end surface is a surface (cap surface) 31 c that comes into contact with the convex portion 28 of the exhaust surface 24 when the exhaust cap 31 covers the exhaust surface 24.

  The cap surface 31 c has flexibility and is more easily deformed than the convex portion 28 of the exhaust surface 24. In this embodiment, the cap surface 31 c of the exhaust cap 31 formed of silicon rubber is deformed more than the convex portion 28 of the exhaust surface 24 of the head unit 20 formed of ABS / PBT resin filled with glass fiber. Easy to do. The size of the outer edge of the cap surface 31 c is larger than the outer edge of the exhaust surface 24. The size of the inner edge of the cap surface 31c is set such that the projection 28 abuts on or near the center between the inner edge and the outer edge of the cap surface 31c. Further, the distance between the inner edge and the outer edge of the cap surface 31 c is set wider than the width between the inner surface and the outer surface of the convex portion 28.

  The exhaust cap 31 is accommodated in the holder 36. The holder 36 is provided with a housing portion, a suction tube 36 a and a plurality of (four in this embodiment) shafts 36 b. The housing portion is a recess whose upper portion is open, and the exhaust cap 31 is housed in the recess. The cap surface 31 c of the accommodated exhaust cap 31 is provided above the upper surface of the holder 36. Therefore, when the holder 36 is lifted, the cap surface 31 c abuts on the exhaust surface 24 earlier than the upper surface of the holder 36. Thus, when the cap surface 31 c abuts on the exhaust surface 24, the opening of the recess is closed by the exhaust surface 24 to form an airtight internal space (closed space) surrounded by the recess and the exhaust surface 24. Ru. The closed space is adjacent to the exhaust port of the exhaust surface 24.

  The upper end opening of the suction tube 36 a corresponds to the suction hole 31 e of the exhaust cap 31 housed in the holder 36. The lower end of the suction tube 36 a is connected to the suction pump 133. Thus, the internal space of the exhaust cap 31 communicates with the suction pump 133 via the suction tube 36 a and the suction hole 31 e.

  The shaft 36 b is slidably provided in the through hole (insertion hole 31 d) formed in the exhaust cap 31, moves so as to be inserted into the opening in a state of being in contact with the exhaust valve 34, and It is a member for opening. For example, the shaft 36b is a rod-like member extending in the vertical direction, and is arranged side by side at intervals in the scanning direction. The shaft 36 b is inserted into the insertion hole 31 d of the exhaust cap 31 housed in the holder 36. The shaft 36 b is configured to be vertically movable with respect to the bottom surface portion 31 a of the exhaust cap 31 while having airtightness between the outer peripheral surface and the edge of the insertion hole 31 d.

  The shaft 36 b corresponding to the exhaust passage 26 for black ink is independently movable in the vertical direction. On the other hand, the three shafts 36b corresponding to the exhaust flow paths 26 of the three color inks (magenta, cyan, yellow) are mutually connected at their lower end portions, and can be integrally vertically moved. ing. A drive motor (not shown) is connected to these shafts 36b, and the black ink shaft 36b and the color ink shaft 36b are vertically moved by the drive motor independently of each other.

  The pressure adjustment unit 33 is a mechanism that changes the pressure in the internal space of the exhaust cap 31, and is configured of, for example, a suction pump 133. The suction pump 133 is connected to the suction hole 31e of the exhaust cap 31 by a suction tube 36a, and is provided with a valve (atmospheric release valve) 33a for opening the internal space of the exhaust cap 31 to the atmosphere. When the air release valve 33 a is closed, the internal space communicates with the suction pump 133. Therefore, when the suction pump 133 is operated with the exhaust cap 31 in close contact with the exhaust surface 24, the suction pump 133 moves the internal space of the exhaust cap 31 mounted on the exhaust surface 24 into the suction tube 36a and the suction hole 31e. The pressure in the internal space is reduced. On the other hand, when the atmosphere release valve 33a is open, the internal space of the exhaust cap 31 is opened to the atmosphere, and the pressure in the internal space returns to the atmospheric pressure. Thus, the pressure in the internal space of the exhaust cap 31 is adjusted.

  The contact / separation part 32 is a mechanism that brings the exhaust cap 31 into contact with and away from the exhaust surface 24. For the contact / separation part 32, for example, a cam 132 which converts the rotational movement into the vertical movement of the exhaust cap 31 is used. A cam drive motor is attached to the shaft portion of the cam 132, and the cam 132 is rotated about the axis by the drive of the cam drive motor. The cam 132 has a substantially circular base circle and a cam lobe projecting outward from the shaft from the base circle. The cam 132 is disposed such that its circumferential surface is in contact with the lower surface of the holder 36.

  When the portion in contact with the holder 36 moves from the base circle to the cam lobe by the rotation of the cam 132, the exhaust cap 31 ascends together with the holder 36, and the cap surface 31c abuts on the exhaust surface 24 of the head unit 20. As a result, the opening of the recess is closed by the exhaust surface 24 to form an airtight closed space surrounded by the recess and the exhaust surface 24. The closed space is adjacent to the exhaust hole of the exhaust surface 24.

  On the other hand, when the portion in contact with the holder 36 moves from the cam lobe to the base circle by the rotation of the cam 132, the exhaust cap 31 also descends by its own weight as the holder 36 descends, and the cap surface 31c separates from the exhaust surface 24 of the head unit 20. .

  The wiper member 35 (see FIG. 1) is a member for wiping off the liquid adhering to the nozzle surface 23 and the softened fillet 50. For example, the wiper member 35 is a thin plate made of rubber or the like, and is moved in the scanning direction by a drive motor (not shown). Thus, the wiper member 35 can move relative to the nozzle surface 23 while being in contact with the nozzle surface 23 in the maintenance area.

  Next, the operation of maintenance for discharging the gas from the exhaust flow path 26 will be described with reference to FIGS. 6A to 6D. This operation is performed by the control unit 40 controlling the contact / separation unit 32, the pressure adjustment unit 33, the exhaust valve 34, the wiper member 35, and the like. FIG. 6A is a view schematically showing a capping state in which the cap surface 31c is in contact with the convex portion 28, and FIG. 6B is a view schematically showing a state in which the gas is discharged from the exhaust flow path 26. FIG. 6C is a view schematically showing a state in which the cap surface 31c is separated from the exhaust surface 24, and FIG. 6D is a view schematically showing a capping state.

  First, when the maintenance operation is started, the head unit 20 is moved by the carriage 22 (FIG. 1) to the maintenance area. Thus, the exhaust surface 24 faces the opening of the recess of the exhaust cap 31 and the cap surface 31 c.

  Then, as shown in FIG. 6A, the exhaust cap 31 is raised. As a result, the cap surface 31 c of the exhaust cap 31 abuts on the convex portion 28 projecting from the exhaust surface 24. Furthermore, when the exhaust cap 31 is raised, the cap surface 31 c that is more easily deformed than the convex portion 28 is recessed by the convex portion 28, and the convex portion 28 is embedded in the recess.

  At this time, when the convex portion 28 is buried, the region of the cap surface 31 c on the inner side of the portion (contact portion) of the cap surface 31 c in contact with the convex portion 28 contacts the region on the inner side of the exhaust surface 24 than the convex portion 28. The area of the cap surface 31 c outside the abutting portion abuts the area outside the exhaust surface 24 from the convex portion 28. For this reason, the cap surface 31 c in the portion from the abutting portion to the outer edge of the cap surface 31 c is parallel to the exhaust surface 24.

  However, the cap surface 31 c of the portion from the abutting portion to the outer edge of the cap surface 31 c may include a portion not parallel to the exhaust surface 24. That is, the cap surface 31 c (outside inclined surface) of the portion immediately outside the abutting portion is inclined with respect to the exhaust surface 24. The distance between the outer inclined surface and the exhaust surface 24 in the vertical direction is narrower than the distance between the contact portion and the exhaust surface 24 and narrows from the contact portion toward the outer edge of the outer cap surface 31 c. Such an outer inclined surface which is not parallel to the exhaust surface 24 may be present on the cap surface 31 c in a portion from the abutting portion to the outer edge of the cap surface 31 c. Similarly, the cap surface 31 c (inner inclined surface) of the portion immediately inside the abutting portion is inclined with respect to the exhaust surface 24. The distance between the inner inclined surface and the exhaust surface 24 in the vertical direction is narrower than the distance between the contact portion and the exhaust surface 24 and narrows from the contact portion toward the inner recess.

  Further, in the capping state in which the convex portion 28 abuts on the cap surface 31 c, the convex portion 28 abuts on the center between the inner edge and the outer edge of the cap surface 31 c or in the vicinity thereof. As a result, the areas of the cap surface 31c inside and outside of the abutting portion abut the areas inside and outside of the exhaust surface 24 more evenly than the convex portion 28, respectively.

  Furthermore, the outer edge of the cap surface 31 c is larger than the outer edge of the exhaust surface 24 and protrudes outward farther from the convex portion 28 than the outer edge of the exhaust surface 24. The cap surface 31 c between the outer edge of the cap surface 31 c and the outer edge of the exhaust surface 24 is parallel to the exhaust surface 24. A wall surface 24 a extending upward from the outer edge of the exhaust surface 24 is perpendicular to the cap surface 31 c between the outer edge of the cap surface 31 c and the outer edge of the exhaust surface 24.

  Then, the exhaust valve 34 is opened to allow the closed space formed by the recess and the exhaust surface 24 to communicate with the exhaust flow path 26. In addition, the air release valve 33a is closed, and the suction pump 133 sucks the internal space with the internal space as a closed space. Thereby, the internal space is depressurized, and the pressure thereof becomes a predetermined pressure of the internal space for discharging the gas from the exhaust flow path 26, for example, -7 kPa. Then, the gas in the exhaust flow path 26 is sucked and discharged through the internal space.

  At this time, since the cap surface 31 c is pressed to the lower end surface side of the convex portion 28, the cap surface 31 c is in close contact with the lower end surface. Moreover, since the lower end surface is formed by a curved surface that curves in the direction orthogonal to the longitudinal direction, the lower end surface is in line contact with the cap surface 31c in the longitudinal direction, and the space between the cap surface 31c and the convex portion 28 is excellent It is airtight and sealed.

  Further, as shown in FIG. 6B, the liquid is discharged together with the gas into the depressurized internal space. The liquid adheres to the inner surface of the recess and the exhaust surface 24 and enters and is held between the cap surface 31 c and the exhaust surface 24 by capillary action. However, as the internal space is decompressed, the cap surface 31 c which is easily deformed is further pressed to the exhaust surface 24 and the convex portion 28 side. Thereby, the liquid in the gap between the exhaust surface 24 and the cap surface 31c and in the gap between the lower end surface, the inner surface and the outer surface of the convex portion 28 and the cap surface 31c is pushed out to the inside or the outside of the convex portion 28 Be

  Although a part of the liquid pushed out to the inside of the convex portion 28 remains in the gap between the inner surface of the convex portion 28 and the inner inclined surface of the cap surface 31 c, most of the remaining liquid flows into the internal space. In addition, although a part of the liquid extruded to the outside of the convex portion 28 remains in the gap between the outer surface of the convex portion 28 and the outer inclined surface of the cap surface 31c, most of the rest is the exhaust surface 24 and the cap surface 31c. Drained from the gap between Since the outer edge of the cap surface 31 c protrudes outward from the outer edge of the exhaust surface 24, the liquid flows out on the cap surface 31 c between the outer edge of the cap surface 31 c and the outer edge of the exhaust surface 24. A portion of the liquid rises from the outer edge of the exhaust surface 24 along the wall surface 24 a orthogonal to the exhaust surface 24.

  Then, as shown in FIG. 6C, the exhaust valve 34 is closed to shut off the internal space from the exhaust flow path 26. Then, when the atmosphere release valve 33a is opened, the internal space is opened to the atmosphere, and the pressure in the internal space returns to the atmospheric pressure or its approximate value. Therefore, when the exhaust cap 31 is lowered, the cap surface 31 c is separated from the exhaust surface 24 without scattering of the liquid adhering to the inner surface of the recess, the exhaust surface 24 and the like.

  Then, the air release valve 33 a is closed to allow the internal space to communicate with the suction pump 133. As a result, air in the internal space is sucked by the suction pump 133 while air flows into the internal space from the opening of the concave portion of the exhaust cap 31, so that the liquid attached to the inner surface of the concave is discharged.

  Thereafter, the wiper member 35 (FIG. 1) is brought into contact with the nozzle surface 23 and the exhaust surface 24 in this order and moved relatively. Thereby, the liquid and fillet 50 attached to the nozzle surface 23 and the exhaust surface 24 are wiped off. Since the nozzle surface 23 is coated with a water repellent coating, the liquid is easily wiped off, but part of the liquid remains on the exhaust surface 24 and the convex portion 28 having high affinity with the liquid without being wiped off. .

  However, as shown in FIG. 6D, when the exhaust cap 31 is raised again, the cap surface 31c is recessed by the projection 28, and the projection 28 is embedded in the recess. At this time, since the cap surface 31 c is pressed against the lower end surface of the convex portion 28 and the exhaust surface 24, the liquid between them is pushed inward or outward of the convex portion 28. Then, the liquid pushed out to the inside of the convex portion 28 flows to the gap between the inner surface of the convex portion 28 and the inner inclined surface of the cap surface 31 c and to the internal space. Further, the liquid extruded to the outside of the convex portion 28 has a gap between the outer surface of the convex portion 28 and the outer inclined surface of the cap surface 31 c and an outer edge of the cap surface 31 c and an outer edge of the exhaust surface 24. It flows on the cap surface 31c.

  Thus, when the exhaust surface 24 is left in contact with the cap surface 31c, the remaining liquid is dried, and the fillet 50 is formed on the exhaust surface 24 having a better affinity than the cap surface 31c. The fillet 50 is a solid or gel of the solute left by evaporation of the liquid solvent. In particular, since the outside of the convex portion 28 is open to the atmosphere, the fillet 50 of the liquid outside the convex portion 28 is easily formed. For example, at normal temperature, the liquid inside the convex portion 28 did not harden even in 30 days, whereas the liquid outside the convex portion 28 solidified in 7 days, and the fillet 50 was formed.

  Most of the liquid remaining outside the convex portion 28 is the liquid on the cap surface 31c between the outer edge of the cap surface 31c and the outer edge of the exhaust surface 24, and the outer inclined surface of the outer surface of the convex portion 28 and the cap surface 31c. The liquid that remains in the gap between Therefore, as shown in FIG. 6C, when the liquid on the cap surface 31c between the outer edge of the cap surface 31c and the outer edge of the exhaust surface 24 dries, the fillet 50 adheres to the wall surface 24a having higher affinity to the liquid than the cap surface 31c. Do. The fillet 50 projects along the cap surface 31c from the wall surface 24a toward the outer edge of the cap surface 31c. Since the cap surface 31 c is in contact with the exhaust surface 24, the fillet 50 does not protrude below the exhaust surface 24. Therefore, as shown in FIG. 6D, even if capping, the fillet 50 is placed on the cap surface 31c, and between the cap surface 31c and the exhaust surface 24, and between the cap surface 31c and the lower end surface of the convex portion 28. Do not get caught between

  In addition, when the liquid remaining in the gap between the outer surface of the convex portion 28 and the outer inclined surface of the cap surface 31 c dries, a fillet 50 attached to the outer surface of the convex portion 28 is formed. The fillet 50 is originally formed in the gap between the convex portion 28 and the outer inclined surface of the cap surface 31 c. For this reason, as shown in FIG. 6D, even if capping, the fillet 50 is fitted in the gap between the convex portion 28 and the outer inclined surface of the cap surface 31c, and between the cap surface 31c and the exhaust surface 24 and , And between the cap surface 31 c and the lower end surface of the projection 28.

  As described above, even if the fillets 50 protruding from the wall surface 24 a and the fillets 50 attached to the convex portions 28 are formed, any fillet 50 is also formed between the cap surface 31 c and the exhaust surface 24 and between the cap surface 31 c and the convex There is no gap between the lower end face of the portion 28 and the lower end face. Therefore, the cap surface 31 c and the lower end surface of the convex portion 28 are in line contact with each other. Therefore, even if the pressure in the internal space of the exhaust cap 31 is not lower than the predetermined pressure for exhaust purge, the lower end surface of the convex portion 28 and the cap surface 31 c can be airtightly adhered. Further, the contact between the cap surface 31 c and the exhaust surface 24 stably maintains the line contact. Therefore, the pressure in the closed space defined by the recess and the exhaust surface 24 is sufficiently reduced, and the exhaust purge for exhausting the gas from the exhaust flow path 26 is performed.

  According to the above embodiment, the convex portion 28 is provided on the exhaust surface 24, and the cap surface 31 c is more easily deformed than the convex portion 28. Therefore, in the capping state in which the convex portion 28 abuts on the cap surface 31 c, the cap surface 31 c is deformed and dented, and the convex portion 28 is buried in this dent. Therefore, since the liquid between the cap surface 31 c and the exhaust surface 24 is pushed out by the convex portion 28, the height of the fillet 50 projecting from the exhaust surface 24 does not become higher than the convex portion 28. Thereby, since the lower end surface of the convex part 28 and the cap surface 31c are in line contact, the gas can be discharged from the exhaust flow path 26 to the internal space without applying a load on the exhaust surface 24.

  Furthermore, in the capping state, the outer edge of the cap surface 31c protrudes outward further away from the convex portion 28 than the outer edge of the exhaust surface 24, and the outer edge of the front cap surface from the contact portion of the cap surface 31c in contact with the convex portion 28 The cap surface 31 c of the part leading to the is parallel to the exhaust surface 24. Thereby, the liquid pushed out by the convex portion 28 flows on the cap surface 31 c between the outer edge of the cap surface 31 c and the outer edge of the exhaust surface 24. Therefore, even if the liquid dries to form the fillet 50, the fillet 50 does not protrude below the cap surface 31c. The fillet 50 is not caught between the cap surface 31 c and the exhaust surface 24 and leak does not occur, and the internal space of the exhaust cap 31 is sufficiently depressurized to discharge the gas from the exhaust flow path 26 to the internal space Can.

  Further, in the capping state, the convex portion 28 is a cap surface such that the distance between the cap surface 31 c on the inner and outer sides of the contact portion and the exhaust surface 24 is narrower than the distance between the contact portion and the exhaust surface 24. It is buried in 31c. Thereby, a gap between the inner inclined surface and the inner surface of the convex portion 28 and a gap between the outer inclined surface and the outer surface of the convex portion 28 are formed. Therefore, the liquid pushed out by the convex portion 28 enters these gaps. Although the liquid dries to form the fillets 50, the fillets 50 adhere to the inner and outer surfaces of the convex portion 28. Therefore, the fillet 50 does not get caught between the cap surface 31 c and the exhaust surface 24 and leak does not occur, and the internal space of the exhaust cap 31 is sufficiently depressurized to transfer the gas from the exhaust passage 26 to the internal space. It can be discharged.

  Furthermore, the head unit 20 is continuous with the portion of the exhaust surface 24 outside the convex portion 28 and extends in the direction orthogonal to the direction in which the convex portion 28 protrudes from the exhaust surface 24 in the direction orthogonal to the exhaust surface 24. Provided in In the capping state, the outer edge of the cap surface 31c is located outside the wall surface 24a. Thus, the liquid flowing on the cap surface 31c between the outer edge of the cap surface 31c and the outer edge of the exhaust surface 24 rises along the wall surface 24a. Therefore, even if the liquid dries to form the fillet 50, the fillet 50 does not protrude below the cap surface 31c. The fillet 50 is not caught between the cap surface 31 c and the exhaust surface 24 and leak does not occur, and the internal space of the exhaust cap 31 is sufficiently depressurized to discharge the gas from the exhaust flow path 26 to the internal space Can.

  Further, a first groove 27 is provided between the nozzle surface 23 and the exhaust surface 24. The first groove 27 is continuous with the portion of the exhaust surface 24 outside the convex portion 28 and extends in the direction orthogonal to the exhaust surface 24 in the direction opposite to the direction in which the convex portion 28 protrudes from the exhaust surface 24. 24 a is provided between the nozzle surface 23 and the exhaust surface 24. Therefore, since the liquid which has flowed to the nozzle surface 23 also rises along the wall surface 24a, the fillet 50 by this liquid does not protrude downward from the cap surface 31c.

  Furthermore, the exhaust surface 24 has a higher affinity to the liquid than the cap surface 31c. Thus, both the liquid and the fillet 50 formed by drying the liquid adhere to the exhaust surface 24. Therefore, these liquids and fillets 50 can be removed by the wiper member 35.

Second Embodiment
The liquid ejection device 10 according to the second embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view schematically showing the head unit 20. As shown in FIG. In the liquid discharge device 10, the convex portion 28 has an inclined surface 28a whose height from the exhaust surface 24 decreases toward the outer edge of the exhaust surface 24.

  That is, the cross section of the convex portion 28 in the plane orthogonal to the longitudinal direction of the convex portion 28 is substantially triangular, and has an inner surface and an inclined surface 28 a. The inner surface linearly extends in a direction perpendicular to the exhaust surface 24. The inclined surface 28 a is inclined such that the height from the exhaust surface 24 is lower as it is away from the inner surface and closer to the outer edge of the exhaust surface 24. The inclination of the inclined surface 28 a is curved so as to increase as it approaches the outer edge of the exhaust surface 24. The lower end connecting the inner surface and the inclined surface 28a is formed by a curved surface that curves between the inner surface and the inclined surface 28a.

  In the capping state in which the cap surface 31c is in contact with the convex portion 28, the cap surface 31c is pressed to the exhaust surface 24 and the convex portion 28 side. Thereby, the liquid in the gap between the cap surface 31 c and the exhaust surface 24 and the protrusion 28 is pushed out to the inside or the outside of the protrusion 28. In particular, since the convex portion 28 is formed by the inclined surface 28 a outside the convex portion 28 which is easily exposed to the outside air, the liquid easily flows to the outer side of the convex portion 28. Thus, a large amount of liquid flows on the cap surface 31c between the outer edge of the cap surface 31c and the outer edge of the exhaust surface 24. Therefore, even if the liquid dries to form the fillet 50, the fillet 50 does not protrude below the exhaust surface 24. Therefore, even if the cap surface 31c is capped again, the fillet 50 does not get caught between the cap surface 31c and the exhaust surface 24 and the convex portion 28, and the exhaust purge can be performed by sufficiently reducing the pressure in the internal space. it can.

Third Embodiment
The liquid discharge device 10 according to the third embodiment will be described with reference to FIG. FIG. 8 is a plan view schematically showing the head surface of the head unit 20. As shown in FIG. The liquid discharge device 10 includes a second groove 29 formed in the exhaust surface 24 so as to extend from the convex portion 28 toward the outer edge of the exhaust surface 24.

  The second groove 29 is an elongated recess for flowing the liquid pushed outward by the convex portion 28 to the outer edge of the exhaust surface 24, and is recessed from the exhaust surface 24. One or more (eight in this embodiment) second grooves 29 are provided in the exhaust surface 24. The second groove 29 is orthogonal to the longitudinal direction of the protrusion 28 and extends from the protrusion 28 toward the outer edge of the exhaust surface 24 in the transport direction or the scanning direction. The second groove 29 is provided such that its inner end reaches the convex portion 28 and its outer end reaches the outer edge of the exhaust surface 24.

  For example, three second grooves 29 extending in the scanning direction from one side of the convex portion 28 are arranged at equal intervals in the transport direction. The second groove 29 at the center of the three second grooves 29 is arranged at equal intervals from the short sides of the two convex portions 28 extending in the scanning direction. The second grooves 29 extending in the transport direction are arranged at equal intervals from the long sides of the two convex portions 28 extending in the transport direction.

  Thus, the second groove 29 formed in the exhaust surface 24 is provided so as to extend from the convex portion 28 toward the outer edge of the exhaust surface 24. Thereby, in the capping state, the liquid pushed out by the convex portion 28 from between the cap surface 31 c and the exhaust surface 24 and the convex portion 28 is transmitted to the outer edge of the exhaust surface 24 through the second groove 29. Therefore, the liquid can be more efficiently discharged from between the cap surface 31 c and the exhaust surface 24 and the convex portion 28.

  In the third embodiment, the second groove 29 is provided orthogonal to the longitudinal direction of the convex portion 28. However, the extending direction of the second groove 29 is not limited to this as long as it is a direction from the convex portion 28 to the outer edge of the exhaust surface 24. For example, the second groove 29 may be provided to be inclined with respect to the longitudinal direction of the protrusion 28.

  Further, in the liquid discharge device 10 according to the third embodiment, the convex portion 28 may have the inclined surface 28a as in the second embodiment.

Embodiment 4
The liquid discharge device 10 according to the fourth embodiment will be described with reference to FIG. FIG. 9 is a plan view schematically showing the exhaust cap 31. As shown in FIG. The liquid discharge device 10 includes a third groove 31 f formed in the cap surface 31 c so as to extend from the position where it can abut on the convex portion 28 in the cap surface 31 c toward the outer edge of the cap surface 31 c.

  That is, the third groove 31 f is an elongated recess for flowing the liquid pushed outward by the convex portion 28 to the outer edge of the exhaust surface 24 and is recessed from the cap surface 31 c. One or more (eight in this embodiment) third grooves 31 f are provided in the cap surface 31 c. The third groove 31f is orthogonal to the longitudinal direction of the contact portion of the cap surface 31c, and extends in the transport direction or the scanning direction from the convex portion 28 toward the edge of the cap surface 31c. The contact portion of the cap surface 31c is a portion that can contact the convex portion 28 on the cap surface 31c. The third groove 31f is provided such that the inner end thereof reaches the abutting portion of the cap surface 31c and the outer end thereof reaches the outer edge of the cap surface 31c. For example, the contact portion of the cap surface 31 c is rectangular with respect to the rectangular convex portion 28 in the exhaust surface 24.

  As described above, the third groove 31 f formed in the cap surface 31 c is provided so as to extend from the position where the cap surface 31 c can contact the convex portion 28 toward the outer edge of the cap surface 31 c. Thereby, in the capping state, the liquid pushed out by the convex portion 28 from between the cap surface 31 c and the exhaust surface 24 and the convex portion 28 travels along the third groove 31 f toward the outer edge of the cap surface 31 c. Therefore, the liquid can be more efficiently discharged from between the cap surface 31 c and the exhaust surface 24 and the convex portion 28.

  In the fourth embodiment, the third groove 31f is provided orthogonal to the longitudinal direction of the contact portion of the cap surface 31c. However, the extending direction of the third groove 31f is not limited to this as long as it is a direction from the contact portion of the cap surface 31c to the outer edge of the cap surface 31c. For example, the third groove 31f may be provided to be inclined with respect to the longitudinal direction of the contact portion of the cap surface 31c.

  Further, in the fourth embodiment, the third groove 31 f is provided such that the inner end thereof reaches the contact portion of the cap surface 31 c and the outer end thereof reaches the outer edge of the cap surface 31 c. However, the outer end of the third groove 31 f may not reach the outer edge of the cap surface 31 c as long as it is closer to the outer edge of the cap surface 31 c than the outer edge of the exhaust surface 24. Thereby, the liquid can be discharged from the outer edge of the exhaust surface 24 to the outside.

  Furthermore, in the liquid discharge device 10 according to the fourth embodiment, the convex portion 28 may have the inclined surface 28 a as in the second embodiment. Furthermore, in the liquid discharge device 10 according to the fourth embodiment, the second groove 29 may be provided in the exhaust surface 24 as in the third embodiment.

(Others)
In all the above-mentioned embodiments, in the capping state, the area of the cap surface 31 c inside and outside of the contact portion abuts on the exhaust surface 24. However, a gap may be formed between the exhaust surface 24 and the area of the cap surface 31 c inside and outside the contact portion. However, when the height of the gap between the cap surface 31 c and the exhaust surface 24 is large, the cap surface 31 c and the convex portion 28 do not make line contact. For this reason, the height of the gap is configured to be, for example, 0.045 mm or less, such that the cap surface 31 c and the convex portion 28 make line contact.

  In all the above embodiments, the lower end surface of the convex portion 28 is formed as a curved surface, but may be a flat surface.

  In all the above embodiments, the air release valve 33a provided in the suction pump 133 is opened to relieve the pressure in the internal space reduced by the pressure reduction process. On the other hand, the method of relieving the pressure of internal space is not limited to this. For example, instead of the suction pump 133, the exhaust cap 31 may be provided with an air release valve 33a.

  In all the embodiments described above, the exhaust cap 31 is moved by the contact / separation part 32 so that the cap surface 31 c of the exhaust cap 31 abuts and is separated from the exhaust surface 24. On the other hand, if it is the contact / separation part 32 which contact | abuts and spaces apart the cap surface 31c of the exhaust cap 31 with respect to the exhaust surface 24, it is not limited to this. For example, the cap surface 31 c of the exhaust cap 31 may be brought into contact with or separated from the exhaust surface 24 by the contact / separation part that moves the head unit 20. Alternatively, the cap surface 31 c of the exhaust cap 31 may abut against and be separated from the exhaust surface 24 by the contact / separation part that moves the exhaust cap 31 and the head unit 20 respectively.

  The above embodiments may be combined with each other as long as the other is not excluded. Also, many modifications and other embodiments of the present invention will be apparent to those skilled in the art from the foregoing description. Accordingly, the above description should be taken as exemplary only, and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the present invention. The structural and / or functional details may be substantially altered without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The liquid discharge apparatus of the present invention is useful as a liquid discharge apparatus or the like that suppresses a defect due to a fillet formed at a contact portion between a cap and an exhaust surface.

10: liquid ejection device 20: head unit 21: head 22: carriage 23: nozzle surface 24: exhaust surface 24a: wall surface 25: nozzle 26: exhaust flow channel 27: first groove 28: convex portion 28a: inclined surface 29: first 2 groove 31: Exhaust cap (cap)
31c: cap surface 31f: third groove 32: cam (contact and separation portion)
33: Suction pump (pressure regulator)
34: Exhaust valve 36b: Shaft 40: Controller 124: Gas storage chamber (liquid flow path)
125b: flexible tube (liquid flow path)

Claims (11)

A head having a nozzle for discharging a liquid, a liquid flow path for supplying the liquid to the head, a gas storage chamber for storing a gas in the liquid flow path, and a gas for discharging the gas in the gas storage chamber A head unit having an exhaust flow path, and an exhaust surface having an opening formed at a downstream end of the exhaust flow path;
A projection projecting from the exhaust surface so as to surround the opening;
A cap which covers the exhaust surface so as to include the opening and which has a cap surface that can be in contact with the convex portion;
And a groove formed in the exhaust surface so as to extend from the convex portion toward the outer edge of the exhaust surface ,
The cap surface has flexibility and is more easily deformed than the convex portion,
In the capping state in which the convex portion is in contact with the cap surface, the outer edge of the cap surface protrudes outward more than the outer edge of the exhaust surface from the convex portion,
In the capping state, the cap surface of a portion from the abutting portion of the cap surface abutting on the convex portion to the outer edge of the cap surface is parallel to the exhaust surface;
The liquid discharge device, wherein the exhaust surface has higher affinity to the liquid than the cap surface.   2. The liquid discharge device according to claim 1, further comprising: a groove formed in the cap surface so as to extend from a position capable of abutting on the convex portion on the cap surface toward an outer edge of the cap surface.   A head having a nozzle for discharging a liquid, a liquid flow path for supplying the liquid to the head, a gas storage chamber for storing a gas in the liquid flow path, and a gas for discharging the gas in the gas storage chamber A head unit having an exhaust flow path, and an exhaust surface having an opening formed at a downstream end of the exhaust flow path;
  A projection projecting from the exhaust surface so as to surround the opening;
  A cap which covers the exhaust surface so as to include the opening and which has a cap surface that can be in contact with the convex portion;
  And a groove formed on the cap surface so as to extend from the position capable of abutting on the convex portion in the cap surface to the outer edge of the cap surface,
  The cap surface has flexibility and is more easily deformed than the convex portion,
  In the capping state in which the convex portion is in contact with the cap surface, the outer edge of the cap surface protrudes outward more than the outer edge of the exhaust surface from the convex portion,
  In the capping state, the cap surface of a portion from the abutting portion of the cap surface abutting on the convex portion to the outer edge of the cap surface is parallel to the exhaust surface;
  The liquid discharge device, wherein the exhaust surface has higher affinity to the liquid than the cap surface.   The liquid discharge device according to claim 3, further comprising a groove formed in the exhaust surface so as to extend from the convex portion toward the outer edge of the exhaust surface. The head unit is continuous with a portion of the exhaust surface outside the convex portion, and further extends in the direction perpendicular to the exhaust surface, a wall surface extending in the direction opposite to the direction in which the convex portion protrudes from the exhaust surface. Have
The liquid ejection device according to any one of claims 1 to 4, wherein in the capping state, an outer edge of the cap surface is positioned outside the wall surface. In the capping state, the convex portion is configured so that the distance between the cap surface on the inner and outer sides of the contact portion and the exhaust surface is narrower than the distance between the contact portion and the exhaust surface. The liquid discharge device according to any one of claims 1 to 5, wherein the liquid discharge device is buried in a cap surface. The head has a nozzle surface on which the nozzle is formed,
The liquid discharge device according to any one of claims 1 to 6 , wherein a head groove is provided in the head unit between the nozzle surface and the exhaust surface. The liquid discharge device according to any one of claims 1 to 7 , wherein the convex portion has an inclined surface whose height from the exhaust surface decreases toward the outer edge of the exhaust surface. A valve which is provided in the vicinity of the opening of the exhaust passage and which always closes the exhaust passage;
And a shaft slidably provided in the through hole formed in the cap, and moved so as to be inserted into the opening in a state where the cap abuts on the exhaust surface to open the valve. The liquid discharge device according to any one of claims 1 to 8 . A head unit having an opening surface having an opening formed therein;
A projection projecting from the opening surface so as to surround the opening;
A cap which covers the opening surface so as to include the opening and which has a cap surface that can be in contact with the convex portion;
And a groove formed in the opening surface so as to extend from the convex portion toward the outer edge of the opening surface,
The cap surface has flexibility and is more easily deformed than the convex portion,
In the capping state in which the convex portion is in contact with the cap surface, the outer edge of the cap surface protrudes outward beyond the outer edge of the opening surface from the convex portion;
In the capping state, the cap surface of a portion from the abutting portion of the cap surface abutting on the convex portion to the outer edge of the cap surface is parallel to the opening surface;
The liquid discharge device, wherein the opening surface has higher affinity to the liquid than the cap surface. A head unit having an opening surface having an opening formed therein;
A projection projecting from the opening surface so as to surround the opening;
A cap which covers the opening surface so as to include the opening and which has a cap surface that can be in contact with the convex portion;
And a groove formed on the cap surface so as to extend from the position capable of abutting on the convex portion in the cap surface to the outer edge of the cap surface,
The cap surface has flexibility and is more easily deformed than the convex portion,
In the capping state in which the convex portion is in contact with the cap surface, the outer edge of the cap surface protrudes outward beyond the outer edge of the opening surface from the convex portion;
In the capping state, the cap surface of a portion from the abutting portion of the cap surface abutting on the convex portion to the outer edge of the cap surface is parallel to the opening surface;
The liquid discharge device, wherein the opening surface has higher affinity to the liquid than the cap surface.

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