JP6844161B2 - Liquid injection head and liquid injection device - Google Patents

Description

The present invention relates to a liquid injection head having a filter for filtering a liquid in a liquid flow path, and a liquid injection device including the same.

The liquid injection device includes a liquid injection head, and is a device that injects (discharges) various liquids from the injection head. As this liquid injection device, for example, there are image recording devices such as an inkjet printer and an inkjet plotter, but recently, various types of liquid injection devices have been manufactured by taking advantage of the feature that a very small amount of liquid can be accurately landed at a predetermined position. It is also applied to devices. For example, a display manufacturing device that manufactures color filters such as liquid crystal displays, an electrode forming device that forms electrodes such as an organic EL (Electro Luminescence) display and a FED (field emission display), and a chip that manufactures a biochip (biochemical element). It is applied to manufacturing equipment. Then, the recording head for the image recording device injects liquid ink, and the color material injecting head for the display manufacturing device injects solutions of each color material of R (Red), G (Green), and B (Blue). Further, the electrode material injection head for the electrode forming apparatus injects a liquid electrode material, and the bioorganic material injection head for the chip manufacturing apparatus injects a solution of the bioorganic substance.

The liquid injection head introduces a liquid into a liquid flow path from a liquid supply source that stores the liquid, and injects the liquid as droplets from a nozzle by driving a driving element (actuator) such as a piezoelectric element or a heat generating element. .. Some of the liquid injection heads have a configuration in which the introduced liquid is filtered and foreign substances and bubbles contained in the liquid are captured by a filter. In the flow path through which the liquid flows, the portion where this filter is installed is a space (hereinafter, filter chamber) in which the cross-sectional area of the flow path is larger than that of the other flow paths. Then, for example, there is a case in which a rib-shaped protrusion is provided in the filter chamber for the purpose of improving the discharge property of air bubbles in the filter chamber (for example, Patent Document 1).

In the above configuration, air bubbles in the filter chamber are generated by applying a negative pressure to the nozzle forming surface on which the nozzle of the liquid injection head is formed, or by pressurizing the liquid in the flow path from the upstream side of the liquid injection head. In the cleaning operation, the flow velocity is increased so that air bubbles in the filter chamber are allowed to enter the gap between the rib-shaped protrusion and the filter and spread so as to cover the filter. By increasing the pressure difference between the air and the air, the air bubbles are discharged to the downstream side. The air bubbles after the cleaning operation are floated from the filter by buoyancy to reduce the contact area with the filter so as not to obstruct the flow of the liquid passing through the filter.

Japanese Unexamined Patent Publication No. 2008-119962

By the way, when the height of the filter chamber cannot be sufficiently secured due to the miniaturization of the liquid injection head, as shown in FIG. 18, the bubble B is narrowly partitioned between the outer peripheral side of the filter 65 and the inner wall surface of the filter chamber. When entering the space, air bubbles B tend to remain in the portion. If the bubbles B remain attached to the outer peripheral side of the filter 65, the flow of the liquid is hindered at that portion. Further, the distance between the rib-shaped protrusion 66 and the filter 65 may not be constant due to assembly variation or the like, and the gap s between the protrusion 66 and the filter 65 may not be sufficiently secured. In this case, The flow of liquid from the central side to the outer peripheral side of the filter 65 cannot be secured. As a result, the discharge property of the bubbles b staying on the downstream side on the outer peripheral side of the filter 65 is lowered. As a result, the time required for the cleaning operation becomes long, and there is a problem that an extra liquid is consumed accordingly.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid injection head capable of further enhancing the discharge property of bubbles and a liquid injection device.

The liquid injection head of the present invention has been proposed to achieve the above object, and the liquid is introduced into the liquid flow path communicating the liquid with the nozzle through the liquid introduction member, and the liquid introduced into the liquid flow path is introduced. A liquid injection head that injects from the nozzle.
The liquid introduction member is
The inlet where the liquid is introduced and
A filter that filters the liquid introduced from the inlet and
A filter chamber in which the cross-sectional area of the flow path expands from the introduction port side to the filter side, and
A supply flow path that supplies the liquid that has passed through the filter to the nozzle side,
With
The filter chamber has a protrusion extending from the inner wall surface of the filter chamber toward the introduction port in the surface direction of the filter.
The protrusion is characterized by having a bypass flow path for flowing a liquid from the introduction port side toward the outer peripheral side of the filter.

According to the present invention, even if air bubbles remain while covering a part of the filter, a bypass flow path through which the liquid can flow from the center side (introduction port side) of the filter to the outer peripheral side of the filter is provided in the protrusion. Has been done. As a result, regardless of the presence of residual air bubbles, the liquid that flows from the inlet side through the bypass flow path toward the outer peripheral side of the filter causes the air bubbles remaining on the downstream side and the outer peripheral side of the filter to flow to the supply flow path side. Therefore, the discharge property of air bubbles is improved. Therefore, the time required for the cleaning operation can be shortened, and as a result, the amount of liquid consumed in the cleaning operation can be reduced. Further, even when the gap between the protrusion and the filter cannot be secured due to an attachment error or the like, at least the flow of the liquid from the introduction port side to the outer periphery of the filter can be secured by the bypass flow path.

In the above configuration, the filter has an elliptical shape.
A plurality of the protrusions are arranged at different positions along the outer circumference of the filter.
At least, it is possible to adopt a configuration in which the bypass flow path is provided at the protrusion located at the position on the inner wall surface where the distance to the introduction port is the longest in the surface direction of the filter.

According to this configuration, the longer the distance from the inlet side to the outer circumference of the filter, the more stagnation occurs on the outer circumference of the filter and the more difficult it is for air bubbles to stay. Therefore, a bypass flow path is provided in the protrusion at such a position. By allowing the liquid to flow from the inlet side to the outer peripheral side of the filter by the bypass flow path, the discharge property of air bubbles at a position where stagnation is likely to occur is improved.

In the above configuration, a protrusion having a relatively long distance to the introduction port in the surface direction of the filter forms a bypass flow path having a longer distance from the filter to the ceiling surface facing the filter. It is desirable to adopt a configuration in which a bypass flow path is formed in which the distance from the filter to the ceiling surface is shorter as the distance to the mouth is relatively shorter.

According to this configuration, the longer the distance from the inlet side to the outer circumference of the filter, the more liquid can flow from the inlet side to the outer circumference side of the filter by the bypass flow path, so that air bubbles can flow on the outer peripheral side of the filter. Is suppressed from staying. Further, even if the dimensions of the gap between the bottom surface of the protrusion and the filter vary due to the mixture of bypass flow paths having different distances from the filter to the ceiling surface in this way, one of the bypass flow paths will be used. , The liquid can be smoothly flowed from the inlet side to the outer peripheral side of the filter. Therefore, it is possible to cope with the dimensional variation of the gap between the bottom surface of the protrusion and the filter.

Further, in the above configuration, it is desirable that the bypass flow path adopts a configuration in which the protrusion is formed in a series from the end on the introduction port side to the end on the outer peripheral side of the filter.

According to this configuration, the liquid can flow to the outer peripheral side of the filter, so that the air bubble discharge property on the outer peripheral side of the filter can be further improved.

Further, in the above configuration, the filter has a first region in which a through hole having a relatively small opening area is formed and a second region in which a through hole having a relatively large opening area is formed.
It is desirable to adopt a configuration in which the second region is arranged in a portion of the filter facing the protrusion.

According to this configuration, the second region is arranged at a position facing the protrusion on the filter, so that the air bubbles on the upstream side of the filter selectively pass through the second region by the liquid flowing through the bypass flow path. It becomes easy to be discharged to the downstream side.

In the above configuration, in the portion of the filter facing the protrusion, the second region may be arranged on the introduction port side of the bypass flow path on the outer peripheral side of the filter. desirable.

According to the above configuration, the liquid once flowing to the outer peripheral side of the filter through the bypass flow path flows toward the second region on the central side in the radial direction of the filter, so that the bubbles staying on the outer peripheral side of the filter are attracted to this. The flow makes it possible to peel off from the inner wall surface of the filter chamber so that the filter can pass through the second region.

Further, in the above configuration, the bypass flow path may adopt a configuration in which the protrusion portion is recessed from the bottom surface facing the filter in a direction orthogonal to the filter.

In this configuration, the bypass flow path can adopt a configuration formed at the center of the bottom surface of the protrusion in a direction orthogonal to the extending direction of the protrusion.

According to the above configuration, on the bottom surface of the protrusion, side wall portions are provided on both sides of the bypass flow path formed in the central portion in the direction orthogonal to the extending direction of the protrusion, so that the bypass flow path is provided. The entry of air bubbles is suppressed. As a result, it is possible to more reliably secure the flow of the liquid from the introduction port side to the outer circumference of the filter.

In this configuration, the bypass flow path may adopt a configuration formed at both ends of the bottom surface of the protrusion in a direction orthogonal to the extending direction of the protrusion.

According to the above configuration, since bypass flow paths are provided at both ends of the bottom surface of the protrusions in a direction orthogonal to the extending direction of the protrusions, a larger flow path cross-sectional area of the bypass flow paths is secured. As a result, it is possible to more reliably secure the flow of the liquid from the introduction port side to the outer circumference of the filter.

The liquid injection device of the present invention includes a liquid injection head having any of the above configurations and a liquid injection head having any of the above configurations.
A maintenance mechanism that discharges liquid and air bubbles from the nozzle of the liquid injection head,
It is characterized by having.

According to this configuration, since the air bubble discharge property during the maintenance operation is improved, it is possible to reduce the time required for the maintenance operation and the amount of liquid consumed in the maintenance operation.

It is a schematic diagram explaining the structure of the liquid injection device (printer). It is sectional drawing of the liquid injection head (recording head). It is sectional drawing of the ink introduction needle in a liquid introduction member (ink introduction member). It is sectional drawing of the main part around a filter chamber. It is a bottom view of the ink introduction needle. It is a top view of a filter. It is sectional drawing of the main part around the filter chamber in maintenance operation. It is sectional drawing of the protrusion part in 2nd Embodiment. It is sectional drawing of the protrusion part in 3rd Embodiment. It is sectional drawing of the main part around the filter chamber in 3rd Embodiment. It is a top view of the filter in 3rd Embodiment. It is sectional drawing in the extending direction of the protrusion explaining the modification of the bypass flow path in 3rd Embodiment. It is sectional drawing of the protrusion part in 4th Embodiment. It is sectional drawing around the filter chamber in 5th Embodiment. It is a top view of the filter in 5th Embodiment. It is a bottom view of the ink introduction needle in the sixth embodiment. It is sectional drawing around the filter chamber explaining the modification of the bypass flow path. It is sectional drawing of the main part around the filter chamber in the conventional structure.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are given as suitable specific examples of the present invention, but the scope of the present invention is the scope of the present invention unless otherwise specified in the following description to limit the present invention. It is not limited to these aspects. Further, in the following, as the liquid injection device to which the present invention is applied, an inkjet recording device (hereinafter, printer) equipped with an inkjet recording head (hereinafter, recording head) which is a kind of liquid injection head will be exemplified.

FIG. 1 is a perspective view illustrating the configuration of the printer 1. The printer 1 is a device that ejects liquid ink toward the surface of a recording medium 2 (target of landing of liquid) such as recording paper to record an image or the like on the recording medium 2. The printer 1 in the present embodiment includes a recording head 3, a carriage 4 that holds the recording head 3, a carriage moving mechanism 5 that reciprocates the carriage 4 in the main scanning direction, which is the width direction of the recording medium 2, and recording. It is provided with a paper feed mechanism 6 or the like that conveys the medium 2 in the sub-scanning direction intersecting the main scanning direction. Here, the above-mentioned ink is a kind of liquid in the present invention, and is stored in an ink cartridge 7 (a kind of liquid supply source). The ink cartridge 7 is detachably attached to the recording head 3. It is also possible to adopt a configuration in which the ink cartridge 7 is arranged not on the carriage 4 but on the main body side of the printer 1, and the ink in the ink cartridge 7 is supplied to the recording head 3 side through the ink supply tube.

In the printer 1, a home position, which is a standby position of the carriage 4, is provided on one end side of the carriage 4 in the main scanning direction. A capping mechanism 9 (a type of maintenance mechanism in the present invention) is arranged at this home position. The capping mechanism 9 has a tray-shaped cap 10 (sealing member) that can come into contact with the nozzle forming surface (nozzle plate 39) on which the nozzle 42 (see FIG. 2) of the recording head 3 is formed. The capping mechanism 9 is configured so that the nozzle 42 of the recording head 3 can be brought into close contact with the nozzle forming surface in a state where the nozzle 42 of the recording head 3 faces the opening on the upper surface side of the cap 10. By setting the cap 10 in close contact with the nozzle forming surface, a sealing empty portion is defined in the cap 10. A pump unit 11 is connected to the cap 10. The pump unit 11 includes, for example, a suction pump such as a tube pump, and the inside of the sealed empty portion can be negatively pressured by the operation of the suction pump. Then, when the suction pump is operated in a state of being in close contact with the nozzle forming surface and the inside of the sealing empty portion (sealed space) is made negative pressure, the ink and air bubbles in the recording head 3 are sucked from the nozzle 42 and the cap 10 is sealed. It is designed to be discharged into the air stop. That is, the capping mechanism 9 performs a cleaning operation, which is a kind of maintenance operation for forcibly sucking and discharging ink and air bubbles in the ink flow path of the recording head 3.

FIG. 2 is a cross-sectional view of the recording head 3 in the present embodiment. The recording head 3 in the present embodiment includes an ink introduction member 12, a relay board 13, an intermediate flow path member 14, a head unit 15, a holder 16, and the like in a laminated manner. In the following, for convenience, the stacking direction of each member will be described as the vertical direction.

A plurality of ink introduction needles 18 are erected on the upper surface of the ink introduction member 12 with the filter 19 interposed therebetween. In the present embodiment, the ink introduction member 12 including the ink introduction needle 18 corresponds to the liquid introduction member in the present invention. The ink introduction needle 18 is provided for each type (color) of ink. Both the ink introduction member 12 and the ink introduction needle 18 are made of synthetic resin. Further, the filter 19 is a member that filters the ink introduced from the ink introduction needle 18, and for example, one in which metal is woven into a mesh or one in which a large number of holes are formed in a thin metal plate is used. Foreign matter and air bubbles in the ink are captured by the filter 19. Then, in the present embodiment, the ink cartridge 7 is mounted on the upper surface of the ink introduction member 12, and the ink introduction needle 18 is inserted into the ink cartridge 7. Then, the ink in the ink cartridge 7 is introduced into the internal flow path from the ink introduction hole 21 provided at the tip of the ink introduction needle 18. When ink is introduced from the ink introduction needle 18, it passes through the filter 19 and passes through the supply flow path 22 to the intermediate flow path member 14 arranged below the ink introduction member 12 via the flow path connecting portion 24. Be supplied. The ink introduction member 12 in the present embodiment adopts a configuration in which the needle-shaped ink introduction needle 18 is inserted into the ink cartridge 7 to introduce ink, but the present invention is not limited to this. For example, a porous material such as a non-woven fabric or a sponge is disposed in the ink introduction portion of the ink introduction member 12, and a similar porous material is provided in the ink lead-out portion of the ink storage member such as an ink cartridge or a sub tank. It is also possible to adopt a so-called foam-type configuration in which the porous members come into contact with each other and ink is transferred by capillarity. In short, it may have an introduction port for introducing ink, a filter for filtering the introduced ink, and a filter chamber provided with this filter.

The intermediate flow path member 14 is a substrate on which an intermediate flow path 25 for guiding the ink introduced from the ink introduction needle 18 to the head unit 15 side is formed. On the upper surface of the intermediate flow path member 14, a cylindrical flow path connecting portion 24 is projected from the peripheral edge of the opening on the entrance side of the intermediate flow path. The height of the flow path connecting portion 24 (protruding length from the upper surface of the intermediate flow path member 14) is set to be equal to or larger than the thickness of the relay board 13 arranged between the ink introduction member 12 and the intermediate flow path member 14. Has been done. Then, the flow path connecting portion 24 communicates with the supply flow path 22 of the ink introduction member 12, receives ink from the ink introduction member 12 side, and introduces the ink into the intermediate flow path 25 side. The intermediate flow path 25 opens on the lower surface of the intermediate flow path member 14 and communicates with the communication flow path 28 provided in the partition plate 27 of the holder 16. Further, the intermediate flow path member 14 is provided with a wiring opening 29 penetrating in the plate thickness direction at a position deviating from the intermediate flow path 25. The wiring opening 29 communicates with the wiring insertion port 30 of the relay board 13 described later, and also communicates with the wiring through port 31 formed in the partition plate 27 of the holder 16, and is an empty portion through which the flexible board 33 is inserted. is there.

The relay board 13 arranged between the ink introduction member 12 and the intermediate flow path member 14 receives a drive signal, injection data (raster data), etc. from the printer main body side, and sends this drive signal to the head through the flexible board 33. This is a printed circuit board on which a wiring pattern or the like for supplying to the piezoelectric element 43 on the unit 15 side is formed. A substrate terminal 34 to be connected to the flexible substrate 33 is formed on the upper surface of the relay board 13 (the surface opposite to the lower surface on the head unit 15 side), and an FFC from the printer main body side is connected. A connector (not shown) and other electronic components are mounted.

An escape hole 35 through which the flow path connecting portion 24 is inserted is provided at a position corresponding to the flow path connecting portion 24 of the intermediate flow path member 14 in the relay board 13. The escape hole 35 is a through hole slightly larger than the outer diameter of the flow path connecting portion 24. Further, at a position adjacent to the substrate terminal 34 on the relay board 13, a wiring insertion port 30 penetrating in the substrate thickness direction is formed along the parallel arrangement direction of the substrate terminal 34. The wiring insertion port 30 is a hole through which the other end side of the flexible substrate 33, one end of which is connected to the element terminal of the piezoelectric element 43, is inserted. The internal dimensions of the wiring insertion port 30 in the longitudinal direction and the lateral direction in the present embodiment are set to such a size that the flexible substrate 33 can be inserted without any trouble.

Inside the holder 16, a plurality of accommodation vacant portions 36, which are spaces capable of accommodating the head unit 15, are partitioned. The accommodation space 36 has an opening on the lower surface side (the side facing the recording medium 2 during the printing operation in the printer 1), and the head unit 15 joined to the fixing plate 37 is accommodated through this opening. The fixing plate 37 is made of, for example, a metal plate material such as stainless steel. By joining the nozzle plates 39 of each head unit 15 to the fixing plate 37, the height direction (position in the direction perpendicular to the nozzle plate 39) of these head units 15 is defined. In the holder 16, a substrate mounting portion 40 on which the intermediate flow path member 14 and the relay substrate 13 are arranged is provided on the upper surface side of the accommodating empty portion 36. The substrate mounting portion 40 and the accommodating empty portion 36 are partitioned by a partition plate 27, and the intermediate flow path member 14 is placed on the upper surface of the partition plate 27. The partition plate 27 is formed with a communication flow path 28 and a wiring through port 31 penetrating in the plate thickness direction. When the head unit 15 is housed in a state of being positioned in the storage space 36, the ink flow path including the nozzle 42 and the pressure chamber 41 of the head unit 15 communicates with the communication flow path 28. As a result, the ink introduced from the ink cartridge 7 through the ink introduction needle 18 is filtered by the filter 19 and then reaches the nozzle 42 of the head unit 15 through the supply flow path 22, the intermediate flow path 25, and the communication flow path 28. Satisfies the ink flow path (corresponding to the liquid flow path in the present invention) up to.

The head unit 15 in the present embodiment includes a nozzle plate 39 in which a nozzle 42 is opened, a pressure chamber 41 communicating with the nozzle 42, a piezoelectric element 43 as a driving element that causes pressure fluctuation in ink in the pressure chamber 41, and the like. ing. The nozzle plate 39 is a plate material in which a plurality of nozzles 42 are formed in a row. In the present embodiment, a plurality of nozzles 42 are arranged in a row at a predetermined pitch to form a nozzle row. The pressure chamber 41 and the piezoelectric element 43 are provided for each nozzle 42. The terminal on one end side of the flexible substrate 33 to which the other end side is connected to the relay substrate 13 is connected to the electrode terminal (not shown) of the piezoelectric element 43. When a drive signal (drive voltage) is applied to the piezoelectric element 43 through the relay substrate 13 and the flexible substrate 33, the piezoelectric active portion of the piezoelectric element 43 bends and deforms in response to a change in the applied voltage, so that the pressure chamber 41 The flexible surface that partitions one surface is displaced toward the nozzle 42 or away from the nozzle 42. As a result, pressure fluctuation occurs in the ink in the pressure chamber 41, and the ink is ejected from the nozzle 42 by utilizing this pressure fluctuation.

FIG. 3 is a cross-sectional view showing a configuration in the vicinity of the ink introduction needle 18 in the ink introduction member 12, and FIG. 4 is an enlarged cross-sectional view of a main part in FIG. 5 is a bottom view of the ink introduction needle 18, and FIG. 6 is a plan view of the filter 19. Regarding FIGS. 3 and 4, the position slightly before the center in the thickness direction of the protrusions 51 shown on the left and right in each drawing (the width direction of the protrusions described later and orthogonal to each drawing) (? A cross section in a direction orthogonal to the plane of the filter 19 in (within the width range of the bypass flow path 54, which will be described later) is shown (hereinafter, the same applies to FIGS. 7, 10, 14, and 17). The ink introduction needle 18 in the present embodiment is a hollow needle-shaped member having an internal space as a needle flow path 47, and is made of, for example, synthetic resin. The ink introduction needle 18 has an enlarged diameter formed by forming a cylindrical portion 45 having a substantially constant flow path cross-sectional area and a filter chamber 20 in which the flow path cross-sectional area gradually expands from the upstream side to the downstream side (filter 19 side). It has a part 46 and.

The cylindrical portion 45 is a portion to be inserted into the ink cartridge 7, and in the present embodiment, the tip portion thereof is formed in a tapered conical shape. A plurality of ink introduction holes 21 for communicating the outside of the ink introduction needle 18 and the needle flow path 47 are provided at the tip portion. As described above, when the cylindrical portion 45 is inserted into the ink cartridge 7, the ink in the cartridge is introduced into the needle flow path 47 through the ink introduction hole 21. The filter chamber 20 is formed continuously on the downstream side of the cylindrical portion 45, and has a substantially conical shape in which the diameter gradually increases from the upstream side (cylindrical portion 45 side) to the downstream side (filter 19 side). The opening shape and area of the lower surface side (outlet side) opening of the filter chamber 20 are aligned with the opening shape and area of the filter 19. The ink introduced into the needle flow path 47 through the ink introduction hole 21 is introduced into the filter chamber 20 from the introduction port 48 at the boundary between the cylindrical portion 45 and the enlarged diameter portion 46 and flows toward the filter 19.

An introduction needle arrangement frame 49 is formed on the upper surface of the ink introduction member 12 so as to surround the ink introduction needle 18 at a portion to which the ink introduction needle 18 is attached, that is, at the peripheral edge of the inlet side opening of the supply flow path 22. .. In the state where the ink introduction needle 18 is arranged inside the introduction needle arrangement frame 49, the circumference of the lower end portion of the enlarged diameter portion 46 of the ink introduction needle 18 is surrounded by the introduction needle arrangement frame 49. Further, a downstream filter chamber 50 is formed at the inlet side opening of the supply flow path 22. The downstream filter chamber 50 is a portion formed so that the cross-sectional area of the flow path gradually increases from the supply flow path 22 side toward the inlet side opening (filter 19 side), and a part of the supply flow path 22 is formed. It is configured. The opening shape and area of the inlet side opening of the downstream filter chamber 50 are aligned with the opening shape and area of the filter 19. Then, the filter 19 is attached in a state of closing the inlet side opening of the downstream filter chamber 50. Further, the ink introduction needle 18 introduces ink by, for example, ultrasonic welding or heat welding in a state where the opening on the lower surface side of the filter chamber 20 faces the filter 19 arranged at the inlet side opening of the downstream filter chamber 50. It is mounted in the introduction needle arrangement frame 49 of the member 12. As a result, the filter chamber 20 (needle flow path 47) of the ink introduction needle 18 and the supply flow path 22 communicate with each other via the filter 19 in a liquid-tight state.

The filter chamber 20 is formed with a protrusion 51 extending from the inner wall surface 20s (outer peripheral side of the filter 19) of the filter chamber 20 toward the introduction port 48 in the surface direction of the flat filter chamber 20. The protrusion 51 in the present embodiment has a substantially triangular rib shape (plate shape) when viewed laterally in a direction orthogonal to the axial direction of the ink introduction needle 18, and as shown in FIG. 5, the filter chamber 20 has a substantially triangular rib shape. A plurality of (four in the present embodiment) are formed radially at different positions along the inner wall surface 20s and the outer periphery of the introduction port 48. The end surface 44 of the protrusion 51 on the introduction port 48 side is arranged so as to be substantially aligned with the opening peripheral edge of the introduction port 48 in a plan view. Further, the bottom surface 53 of the protrusion 51, that is, the surface facing the filter 19, is slightly upstream from the filter 19 and forms a gap 52 with the filter 19. The gap 52 is provided not only for the purpose of functioning as a flow path through which ink can pass, but also for the purpose of spreading air bubbles in the filter chamber 20 to the filter 19 during a cleaning operation described later, for example, 0.1 [. It is desirable that it is about mm]. However, the size of the gap 52 may not be constant and may vary due to an attachment error between the ink introduction member 12, the ink introduction needle 18, and the filter 19. Then, when the air bubbles remaining on the upstream side of the filter 19 remain attached to the filter 19, the ink cannot pass through the portion, and the downstream side of the filter 19, particularly the filter 19, There is a risk that the discharge of air bubbles remaining on the outer peripheral side will deteriorate.

Therefore, the bottom surface 53 of the protrusion 51 in the present embodiment is provided with a bypass flow path 54 that guides the ink flowing from the introduction port 48 to the outer peripheral side of the filter 19. The bypass flow path 54 is a groove-shaped space formed by partially recessing the bottom surface 53 of the protrusion 51 in a direction orthogonal to the filter 19 (axial direction of the ink introduction needle 18). More specifically, in a direction orthogonal to the extending direction of the protrusion 51 (hereinafter, referred to as a protrusion width direction), a rib shape narrower than the protrusion 51 is formed at the center of the bottom surface 53 of the protrusion 51. The corners on both sides where the bottom surface 53 and the side surface 55 of the protrusion 51 intersect are formed in a rectangular shape with the small protrusion 59 left, and the shape of the bottom surface side of the protrusion 51 is It has an inverted convex shape. That is, the bypass flow path 54 in the present embodiment is a space partitioned by a vertical wall portion 54sw substantially parallel to the side surface 55 of the protrusion 51 and a ceiling portion 54cl substantially parallel to the bottom surface 53 of the protrusion 51. It has become. The bypass flow path 54 in the present embodiment is formed in a series from the end surface 44 on the introduction port 48 side of the protrusion 51 to the outer peripheral end (apex) of the filter 19, that is, from the inner wall surface 20s of the filter chamber 20. ing.

Regarding the dimensions of the bypass flow path 54, it is desirable that the height h (dimension in the direction orthogonal to the filter 19) is, for example, 0.1 [mm] or more and 0.4 [mm] or less. By setting the lower limit of the height h to 0.1 [mm], for example, even when there is almost no gap 52 between the bottom surface 53 of the protrusion 51 and the filter 19 due to a mounting error or the like. A gap of at least 0.1 [mm] is secured in the bypass flow path 54. Further, when the upper limit value of the height h exceeds 0.4 [mm], it is contained in the bypass flow path 54, although it depends on the size of the gap between the bottom surface 53 of the protrusion 51 and the filter 19. Since bubbles are likely to enter, it is possible to suppress the entry of bubbles into the bypass flow path 54 by setting the upper limit value to 0.4 [mm]. Further, it is desirable that the width w (dimension in the width direction of the protrusion) of the bypass flow path 54 is, for example, about 1/3 of the width W of the protrusion 51. During the cleaning operation, the protrusion 51 having such a configuration guides the air bubbles in the filter chamber 20 to the gap 52 and spreads the air bubbles in the filter chamber 20 toward the outer periphery of the filter 19 along the filter 19. Thereby, the air bubble discharge property in the cleaning operation can be improved. Further, the bypass flow path 54 provided in the protrusion 51 can secure the flow of ink from the center side (introduction port 48 side) of the filter 19 toward the outer peripheral side of the filter 19.

The filter 19 is, for example, a thin metal plate such as stainless steel in which through holes 56 through which ink and air bubbles can pass are formed. The through hole 56 in the present embodiment is formed as a circular through hole by, for example, pressing or laser processing the metal plate used as the material of the filter 19. Further, the shape of the filter 19 having such a through hole 56 can also be formed by electroforming. The filter 19 has a first region 57 in which a first through hole 56a having a relatively small opening area is formed, and a second region 58 in which a second through hole 56b having a relatively large opening area is formed. The second region 58 is arranged in a portion (a portion facing the protrusion 51) on which the protrusion 51 of the filter 19 is projected in a direction orthogonal to the filter 19. That is, in the present embodiment, the entire portion of the filter 19 facing the protrusion 51 is the second region 58. Regarding the size (inner dimension) of the second through hole 56b, for example, 13 [μm] so as to facilitate the passage of air bubbles and trap foreign matter larger than the inner diameter of the nozzle 42 (for example, 20 [μm]). ] And above, it is set to 18 [μm] or less. Further, regarding the size of the first through hole 56a, for example, it is set to 5 [μm] or more and 12 [μm] or less in order to make it difficult for air bubbles to pass through while the ink can pass through. In such a configuration, the second region 58 is easier for air bubbles to pass through than the first region 57. Then, by arranging such a second region 58 below the protrusion 51, air bubbles on the upstream side of the filter 19 selectively pass through the second region 58 by the ink flowing through the bypass flow path 54. It is easy to be discharged to the downstream side. Regarding the shape of the through hole 56, in the present embodiment, a circular shape is exemplified, but the shape is not limited to this, and various shapes such as a quadrangular shape can be adopted. Further, the filter 19 is not limited to a metal plate having through holes 56 formed therein, and for example, a filter 19 having through holes through which liquids and bubbles can pass is formed by sintering a ceramic material. Is.

FIG. 7 is a cross-sectional view of the vicinity of the filter 19 in the cleaning operation.
In this type of printer 1, when the ink introduction needle 18 is inserted into and removed from the ink cartridge 7, air bubbles may enter the needle flow path 47. The bubbles are trapped in the filter chamber 20 by the filter 19, but gradually become larger as the bubbles combine with each other. In the printer 1, the recording head 3 mounted on the carriage 4 is positioned at the home position, and the capping mechanism 9 periodically performs a cleaning operation to discharge air bubbles B in the filter chamber 20. In this cleaning operation, a suction mechanism such as a suction pump is operated in a capping state in which the cap 10 is in close contact with the nozzle forming surface (nozzle plate 39) of the recording head 3 to generate a negative pressure in the cap, which is normal. A flow of ink having a flow velocity faster than the flow velocity during the recording operation is generated in the ink flow path, and air bubbles in the filter chamber 20 are passed through the filter 19 by using the flow force of the ink to flow from the nozzle 42 to the outside of the head. Discharge. Regarding the cleaning operation, the ink supply path on the upstream side (ink cartridge 7 side) of the recording head 3 is pressurized by a pressurizing mechanism such as an air pump to pressurize the inside of the flow path of the recording head 3. It is also possible to perform a pressure-type cleaning operation for discharging thickened ink, air bubbles, and the like from the nozzle 42.

When the flow rate of the ink is increased in the cleaning operation, the air bubbles in the filter chamber 20 are pressed against the filter 19 by the downward force of the ink flowing from the upstream side. At this time, a part of the bubble B slips into the gap 52 between the protrusion 51 and the filter 19, and is spread along the filter 19 toward the outer circumference of the filter 19. Then, when the air bubbles cover almost the entire surface of the filter 19 (a state of choking), a pressure difference larger than that before the choke is generated between the upstream side and the downstream side across the filter 19, and the pressure difference causes the air bubbles. Most pass through the filter 19. In the present embodiment, the air bubbles mainly pass through the second through hole 56b of the second region 58 arranged below the protrusion 51 in the filter 19. At this time, the bubbles B on the upstream side of the filter 19 pass through the filter 19 and are divided into finer bubbles b. The bubbles that have passed through the filter 19 flow from the supply flow path 22 to the downstream side (nozzle 42 side) along with the flow of ink, and are discharged from the nozzle 42 into the cap 10.

By the way, as shown in FIG. 7, even in the cleaning operation, a part of the air bubbles in the filter chamber 20 may not pass through the filter 19 and may remain in a state of covering a part of the filter 19. In particular, when the bubble B enters the narrow space partitioned by the outer peripheral side of the filter 19 and the inner wall surface 20s of the filter chamber 20, the bubble B tends to remain in the portion. In the recording head 3 according to the present invention, even if such a situation occurs, a bypass flow path 54 that allows ink to flow from the center side (introduction port 48 side) of the filter 19 to the outer peripheral side of the filter 19 is provided. Since it is provided on the protrusion 51, ink may flow from the introduction port 48 side to the outer peripheral side of the filter 19 through the bypass flow path 54 (side of the bubble B) regardless of the presence of residual air bubbles B. it can. As a result, as shown by the white arrows in FIG. 7, the bubbles b remaining on the downstream side and the outer peripheral side of the filter 19 are swept away to the supply flow path 22 side, so that the discharge property of the bubbles is improved. Therefore, in the printer 1 according to the present invention, the time required for the cleaning operation can be shortened, and as a result, the amount of ink consumed in the cleaning operation can be reduced. Further, even if the gap 52 cannot be secured due to an attachment error between the ink introduction member 12, the ink introduction needle 18, and the filter 19, at least the bypass flow path 54 is directed from the introduction port 48 side toward the outer periphery of the filter 19. The ink flow can be ensured.

Further, since the ink flowing to the outer peripheral side of the filter 19 through the bypass flow path 54 can peel off the bubbles B remaining on the upstream side of the filter 19 from the inner wall surface 20s of the filter chamber 20, the outer peripheral side of the filter 19 can be peeled off. It is suppressed that the bubble B stays in the ink. Even if the bubbles B peeled off from the inner wall surface 20s are discharged through the filter 19 (particularly the second region 58) along with the ink flow, or remain in the filter chamber 20 after cleaning. , It floats from the filter 19 due to buoyancy and separates from the surface of the filter 19. Therefore, it is possible to prevent the bubbles B from covering the filter 19, thereby preventing the ink flow from being obstructed by the bubbles even after cleaning. The bypass flow path 54 in the present embodiment is formed in a series from the end on the introduction port 48 side to the outer peripheral side end of the filter 19 at the protrusion 51, so that ink flows to the outer peripheral side of the filter 19. Therefore, it is possible to further improve the air bubble discharge property on the outer peripheral side of the filter. Further, since bypass flow paths 54 are provided at both ends of the bottom surface 53 of the protrusion 51 in a direction orthogonal to the extending direction of the protrusion 51, a larger flow path cross-sectional area of the bypass flow path 54 is secured. .. As a result, it is possible to more reliably secure the flow of ink from the introduction port 48 side toward the outer circumference of the filter.

FIG. 8 is a cross-sectional view of the protrusion 51 in the width direction according to the second embodiment of the present invention. In the first embodiment, both corners in the width direction of the protrusion 51 are left at the center of the bottom surface 53 of the protrusion 51 in the width direction. Although the configuration in which the portion is cut out to exhibit an inverted convex shape is illustrated, the present invention is not limited to this. In the second embodiment shown in FIG. 8, the central portion of the bottom surface 53 of the protrusion 51 in the width direction is recessed in the direction orthogonal to the filter 19 to form the bypass flow path 54. As a result, the bottom surface side of the protrusion 51 in the present embodiment is concave in cross-sectional view. In other words, the rib-shaped small protrusions 60a and 60b, which are narrower than the protrusions 51, project in the direction orthogonal to the filter 19 from the positions deviated from the center in the width direction of the protrusions on the lower surface of the protrusions 51, respectively. The space between these small protrusions 60a and 60b is a bypass flow path 54. The configuration other than the bypass flow path 54 is the same as that of the first embodiment. According to the configuration of the present embodiment, since side walls composed of small protrusions 60a and 60b are provided on both sides of the bypass flow path 54, air bubbles are provided in the bypass flow path 54 as compared with the configuration of the first embodiment. Is suppressed from entering. As a result, it is possible to more reliably secure the flow of ink from the introduction port 48 side toward the outer circumference of the filter 19.

FIG. 9 is a cross-sectional view of the protrusion 51 in the width direction according to the third embodiment of the present invention. Further, FIG. 10 is a cross-sectional view of the periphery of the filter chamber 20 in the third embodiment. Further, FIG. 11 is a plan view of the filter 19 according to the third embodiment. In each of the above embodiments, the bottom surface 53 of the protrusion 51 is partially recessed to form the bypass flow path 54, in other words, the bypass flow path 54 is open to the bottom surface 53 of the protrusion 51. However, it is not limited to this. In the third embodiment shown in FIG. 9, both side surfaces 55 of the protrusion 51 are formed in a state where the beam portion 61 is left in the central portion in the width direction of the protrusion and the bottom plate 62 is left between the beam portion 61 and the bottom surface 53. Bypass flow paths 54L and 54R are formed by being recessed in the width direction of the protrusion. In this configuration, with respect to the bypass flow paths 54L and 54R, the end (inlet) on the introduction port 48 side opens to the end surface 44 on the introduction port 48 side of the protrusion 51, and the outer peripheral end (outlet) of the filter 19 is. , It is open to the bottom surface 53 of the protrusion 51. That is, the bypass flow paths 54L and 54R in the present embodiment are formed substantially parallel to the filter 19 from the end on the introduction port 48 side to the middle of the extending direction of the protrusion 51, and from that middle, on the outer peripheral side of the filter 19. Up to the end, it is formed along the inner wall surface 20s of the filter chamber 20. The extending direction of the bypass flow path 54 is not limited to a configuration in which the direction changes in the middle. For example, the bypass flow path 54 is inclined in a direction approaching the filter 19 from the end on the introduction port 48 side toward the outer peripheral end of the filter 19. Alternatively, the configuration may be such that the filter 19 is smoothly curved (without having a corner portion) with a predetermined curvature from the end on the introduction port 48 side toward the outer peripheral side end of the filter 19. You may.

As described above, in the third embodiment, the bypass flow paths 54L and 54R are not opened to the bottom surface 53 of the protrusion 51 except for the outer peripheral end (exit) of the filter 19. Therefore, the bypass flow path 54 having a constant cross-sectional area can be secured regardless of the size of the gap 52 between the protrusion 51 and the filter 19. Moreover, since the bypass flow paths 54L and 54R are formed on both sides of the protrusion 51, it is possible to secure a larger cross-sectional area of the bypass flow path 54.

Further, regarding the filter 19, in the first embodiment, the configuration in which the entire portion of the filter 19 facing the protrusion 51 is the second region 58 is illustrated, but in the present embodiment, the protrusion in the filter 19 is illustrated. The second region 58 is provided in a portion facing the 51 and in a range on the center side (introduction port 48 side) in the radial direction of the filter 19 from the outer peripheral side end of the filter 19 of the bypass flow path 54. As a result, as shown in FIG. 10, the ink entering from the end of the bypass flow path 54 on the introduction port 48 side once flows through the bypass flow path 54 to the outer peripheral side of the filter 19, and then flows in the radial direction of the filter 19. Since it flows toward the second region 58 on the central side of the filter chamber 20, air bubbles staying on the outer peripheral side of the filter 19 can be peeled off from the inner wall surface 20s of the filter chamber 20 so as to pass through the filter 19 from the second region 58. It will be possible. As described above, regarding the second region 58 of the filter 19, the entire portion where the protrusion 51 is projected on the filter 19 does not necessarily have to be the second region 58, and in addition to the configuration in the present embodiment, for example, the protrusion The second region 58 may be arranged within a range in which the dimension in the width direction of the protrusion is narrower than the projected portion of the 51. In short, since the second region 58 is arranged in the range of the filter 19 facing the protrusion 51, the air bubbles on the filter 19 can be discharged through the second region 58 in the cleaning operation. .. The other configurations are the same as those of the first embodiment or the second embodiment.

FIG. 12 is a cross-sectional view of the protrusion 51 in the extending direction (direction parallel to the filter 19) for explaining a modification of the bypass flow path 54 in the third embodiment. Regarding the bypass flow path 54 in the present embodiment, the outer peripheral end (exit) of the filter 19 does not necessarily have to open to the bottom surface 53 of the protrusion 51. In the modified example shown in FIG. 13, the end surface 63 of the bypass flow path 54 on the outer peripheral side of the filter 19 is inclined in a direction closer to the side (outside the protrusion 51) as it approaches the outer periphery of the filter 19. Therefore, as shown by the white arrows in the figure, the ink flow of the bypass flow path 54 substantially follows the radial direction of the filter 19 to the side (circumferential direction of the filter 19) on the outer peripheral side of the filter 19. Since the direction is changed), it is possible to easily peel the air bubbles on the outer peripheral side of the filter 19 between the adjacent protrusions 51 from the inner wall surface 20s of the filter chamber 20. Thereby, the bubble discharge property can be further improved. The end surface 63 is not limited to a flat surface, and may be formed of a curved surface.

FIG. 13 is a cross-sectional view of the protrusion 51 in the width direction according to the fourth embodiment of the present invention. In the present embodiment, the bypass flow path 54 is formed inside the protrusion 51, and is a space surrounded by the upper, lower, left, and right walls in a cross-sectional view. In this configuration, the end of the bypass flow path 54 on the introduction port 48 side opens to the end surface 44 of the protrusion 51 on the introduction port 48 side, and the end of the bypass flow path 54 on the outer peripheral side of the filter 19 is shown in FIG. Similar to the configuration of the third embodiment shown in the above, the protrusion 51 has an opening on the bottom surface 53. The bypass flow path 54 in this configuration does not open to the outer surface of the protrusion 51 except at both ends (entrance and exit). As a result, air bubbles are more reliably prevented from entering the bypass flow path 54. The configuration other than the bypass flow path 54 is the same as in each of the above embodiments.

FIG. 14 is a cross-sectional view of the periphery of the filter chamber 20 for explaining the configuration of the fifth embodiment of the present invention. Further, FIG. 15 is a plan view illustrating the configuration of the filter 19 according to the fifth embodiment. The present embodiment is different from each of the above-described embodiments in that the supply flow path 22 is eccentric to the center of the filter 19 (on the right side in FIG. 14). Further, the filter 19 is different from each of the above-described embodiments in that the second region 58 is arranged only at a position facing the protrusion 51 located on the supply flow path 22 side of the center of the filter 19. .. According to the configuration of the present embodiment, the air bubbles on the filter 19 can be selectively passed through the second region 58 located closer to the supply flow path 22 and discharged. This makes it possible to discharge the air bubbles in the filter chamber 20 in a shorter time in the cleaning operation. Further, on the side of the filter 19 farther from the supply flow path 22 (the side opposite to the direction in which the supply flow path 22 is eccentric with respect to the center of the filter 19), ink can pass through, but bubbles are difficult to pass through. The retention of air bubbles on the downstream side of the filter 19 at the position is suppressed. The other configurations are the same as those in each of the above embodiments.

FIG. 16 is a bottom view of the ink introduction needle 18 for explaining the configuration of the sixth embodiment. In each of the above embodiments, the shape seen from the lower surface side of the filter chamber 20 (the cross-sectional shape of the flow path along the surface direction of the filter 19) is substantially a perfect circle. Not limited. In the present embodiment, the filter 19 has an elliptical shape, and the cross-sectional shape of the filter chamber 20 has an elliptical shape accordingly. That is, the inner diameter D2 in the direction orthogonal to the direction (horizontal direction in FIG. 16) is longer than the inner diameter D1 in one direction (vertical direction in FIG. 16) of the lower surface side opening of the filter chamber 20. In such a configuration in which the filter 19 and the filter chamber 20 have an elliptical shape, there is a difference in the distance from the introduction port 48 side to the outer circumference of the filter 19. In such a configuration, if at least the bypass flow path 54 is formed in the protrusion 51 located on the inner wall surface 20s of the filter chamber 20 having the longest distance to the introduction port 48 in the surface direction of the filter 19. Good.

In the present embodiment, the bypass flow path 54a is formed in the protrusion 51a extending along the longitudinal direction of the filter 19 (the direction along the inner diameter D2 of the filter chamber 20), while the short side of the filter 19 is short. A bypass flow path 54 is not provided in the protrusion 51c extending along the direction (direction along the inner diameter D1 of the filter chamber 20). Further, a bypass flow path 54b is provided in the protrusion 51b arranged between the protrusions 51a and 51c. That is, the shorter the distance from the introduction port 48 side to the outer circumference of the filter 19, the easier it is for the ink to flow to the outer circumference of the filter 19, and the more difficult it is for air bubbles to stay in this portion. The longer the distance from the introduction port 48 side to the outer circumference of the filter 19, the more stagnation occurs on the outer circumference of the filter 19 and it is difficult for air bubbles to stay. Therefore, ink is introduced from the introduction port 48 side to the outer circumference side of the filter 19 by the bypass flow path 54. It is desirable to let it flow to. As a result, the dischargeability of air bubbles at a position where stagnation is likely to occur is improved.

Further, with respect to the height h (see FIG. 4) of the bypass flow path 54 opened in the bottom surface 53 of the protrusion 51, the bypass of the protrusion 51 in which the distance from the introduction port 48 side to the outer circumference of the filter 19 is relatively long. The height h of the flow path 54 is formed to be higher, while the height of the bypass flow path 54 of the protrusion 51, which is relatively short from the introduction port 48 side to the outer circumference of the filter 19, is higher. It is also possible to configure the structure so that h becomes smaller. That is, the protrusion 51 having a relatively long distance from the introduction port 48 side to the outer circumference of the filter 19 has a longer bypass flow path 54 from the filter 19 to the ceiling portion 54 cl (see FIG. 4) facing the filter. On the other hand, as the protrusion 51 having a relatively short distance from the introduction port 48 side to the outer circumference of the filter 19, the bypass flow path 54 having a shorter distance from the filter 19 to the ceiling portion 54 cl is formed. May be good. As a result, the longer the distance from the introduction port 48 side to the outer circumference of the filter 19, the more ink can flow from the introduction port 48 side to the outer circumference side of the filter 19 by the bypass flow path 54, so that the outer circumference of the filter 19 can be flowed. The retention of air bubbles on the side is suppressed. Further, even if the dimensions of the gap 52 between the bottom surface 53 of the protrusion 51 and the filter 19 vary due to the mixture of the bypass flow paths 54 having different heights h, any of the bypass flow paths According to 54, the ink can be smoothly flowed from the introduction port 48 side to the outer peripheral side of the filter 19. Therefore, it is possible to cope with the dimensional variation of the gap 52 between the bottom surface 53 of the protrusion 51 and the filter 19. The other configurations are the same as those in each of the above embodiments.

FIG. 17 is a cross-sectional view of the periphery of the filter chamber 20 for explaining a modified example of the bypass flow path 54. The bypass flow path 54 is not limited to the configuration formed from the end surface 44 on the introduction port 48 side of the protrusion 51 to the inner wall surface 20s of the filter chamber 20. As shown in the figure, it is also possible to adopt a configuration in which the bypass flow path 54 is formed in the protrusion 51 from the end surface 44 on the introduction port 48 side to the middle of the protrusion 51 in the extending direction. The bypass flow path 54 in the present embodiment opens as an outlet to the bottom surface 53 of the protrusion 51 in front of the inner wall surface 20s of the filter chamber 20. In short, if ink flows from the introduction port 48 side toward the outer peripheral side of the filter 19 in the surface direction of the filter 19, the discharge property of air bubbles on the outer peripheral side of the filter 19 can be improved. Further, in this configuration, the portion of the filter 19 facing the protrusion 51, which is the center side (introduction port 48) in the radial direction of the filter 19 from the outer peripheral end (outlet) of the filter 19 of the bypass flow path 54. It is desirable to adopt a configuration in which the second region 58 is arranged in the range of (side). As a result, the ink entering from the end of the bypass flow path 54 on the introduction port 48 side once flows through the bypass flow path 54 to the outer peripheral side of the filter 19, and then the second region on the center side in the radial direction of the filter 19. Since it flows toward 58, it is possible to allow air bubbles staying on the outer peripheral side of the filter 19 to pass through the filter 19 from the second region 58.

In each of the above embodiments, the inkjet recording head 3 has been described as an example of the liquid injection head, but the present invention can also be applied to other liquid injection heads. For example, a color material injection head used for manufacturing a color filter such as a liquid crystal display, an electrode material injection head used for electrode formation of an organic EL (Electro Luminescence) display, a FED (surface emitting display), and a biochip (biochemical element). The present invention can also be applied to a bioorganic substance injection head or the like used in the production of). The color material injection head for display manufacturing equipment injects a solution of each color material of R (Red), G (Green), and B (Blue) as a kind of liquid. Further, the electrode material injection head for the electrode forming apparatus injects a liquid electrode material as a kind of liquid, and the bioorganic matter injection head for a chip manufacturing apparatus injects a solution of a bioorganic substance as a kind of liquid.

1 ... printer, 2 ... recording medium, 3 ... recording head, 4 ... carriage, 5 ... carriage moving mechanism, 6 ... paper feed mechanism, 7 ... ink cartridge, 9 ... capping mechanism, 10 ... cap, 11 ... pump unit, 12 ... ink introduction member, 13 ... relay board, 14 ... intermediate flow path member, 15 ... head unit, 16 ... holder, 18 ... ink introduction needle, 19 ... filter, 20 ... filter chamber, 21 ... ink introduction hole, 22 ... supply flow path, 24 ... flow path connection Part, 25 ... Intermediate flow path, 27 ... Partition plate, 28 ... Communication flow path, 29 ... Wiring opening, 30 ... Wiring insertion port, 31 ... Wiring through port, 33 ... Flexible board, 34 ... Board terminal, 35 ... Escape hole, 36 ... Storage space, 37 ... Fixed plate, 39 ... Nozzle plate, 40 ... Board mounting part , 41 ... pressure chamber, 42 ... nozzle, 43 ... piezoelectric element, 44 ... end face, 45 ... cylindrical part, 46 ... enlarged diameter part, 47 ... needle flow path, 48 ... introduction port, 49 ... introduction needle arrangement frame, 50 ... downstream filter chamber, 51 ... protrusion, 52 ... gap, 53 ... bottom surface, 54 ... bypass flow Road, 55 ... Side, 56 ... Through hole, 57 ... 1st area, 58 ... 2nd area, 59 ... Small protrusion, 60 ... Small protrusion, 61 ... Beam Part, 63 ... End face

Claims (10)

A liquid injection head that introduces a liquid into a liquid flow path that communicates with a nozzle through a liquid introduction member and injects the liquid introduced into the liquid flow path from the nozzle.
The liquid introduction member is
The inlet where the liquid is introduced and
A filter that filters the liquid introduced from the inlet and
A filter chamber in which the cross-sectional area of the flow path expands from the introduction port side to the filter side, and
A supply flow path that supplies the liquid that has passed through the filter to the nozzle side,
With
The filter chamber has a protrusion extending from the inner wall surface of the filter chamber toward the introduction port in the surface direction of the filter.
The protrusion is open to the end surface of the protrusion on the introduction port side, and a bypass flow path for flowing a liquid from the introduction port side toward the outer peripheral side of the filter is formed. Liquid injection head. The filter has an elliptical shape and has an elliptical shape.
A plurality of the protrusions are arranged at different positions along the outer circumference of the filter.
The liquid according to claim 1, wherein the bypass flow path is provided at least on the protrusion located at the position on the inner wall surface where the distance to the introduction port is the longest in the surface direction of the filter. Injection head. A protrusion having a relatively long distance to the introduction port in the surface direction of the filter forms a bypass flow path having a longer distance from the filter to the ceiling surface facing the filter, and the distance to the introduction port. The liquid injection head according to claim 2, wherein a bypass flow path is formed in which the distance from the filter to the ceiling surface is shorter as the protrusion is relatively shorter. The bypass flow path according to any one of claims 1 to 3, wherein the bypass flow path is formed in a series from the end on the introduction port side to the end on the outer peripheral side of the filter at the protrusion. Liquid injection head. The filter has a first region in which a through hole having a relatively small opening area is formed and a second region in which a through hole having a relatively large opening area is formed.
The liquid injection head according to any one of claims 1 to 4, wherein the second region is arranged in a portion of the filter facing the protrusion. The fifth aspect of the fifth aspect of the filter, wherein the second region is arranged on the introduction port side of the bypass flow path on the outer peripheral side of the filter in a portion facing the protrusion. Liquid injection head. The liquid according to any one of claims 1 to 6, wherein the bypass flow path is a groove formed by partially recessing the bottom surface of the protrusion facing the filter. Injection head. The liquid injection head according to claim 7, wherein the bypass flow path is formed at a central portion of the bottom surface of the protrusion in a direction orthogonal to the extending direction of the protrusion. The liquid injection head according to claim 7, wherein the bypass flow path is formed at both ends of the bottom surface of the protrusion in a direction orthogonal to the extending direction of the protrusion. A liquid injection device comprising the liquid injection head according to any one of claims 1 to 9.

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