JP2012210770A - Liquid injection head and liquid injection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection head and a liquid injection apparatus which are capable of preventing a meniscus from being broken due to propagation of an impact caused by the rocking, etc. of a liquid storage member through a liquid in a flow path, and which are capable of recovering gas mixed with the liquid in the flow path.SOLUTION: The liquid injection head 2 is capable of introducing the liquid to the side of a pressure chamber 34 from a liquid introduction part 12, into which the liquid is introduced, through a liquid flow path, and capable of injecting the liquid in the pressure chamber 34 from a nozzle 21 as a liquid droplet by the operation of a pressure generation means 44. A filter chamber 51 including a filter 17 filtering the liquid in the liquid flow path is formed in the liquid introduction part 12, a gas chamber 16 storing the gas inside is formed above the filter 17 of the filter chamber 51 in the direction of gravitational force, and the gas chamber 16 and the filter chamber 51 are communicated with each other.

Description

  The present invention relates to a liquid jet head such as an ink jet recording head, and in particular, introduces a liquid stored in a liquid storage member into a pressure chamber through a liquid introduction needle, and introduces the liquid introduced into the pressure chamber from a nozzle. The present invention relates to a liquid ejecting head that ejects droplets and a liquid ejecting apparatus.

  Examples of the liquid ejecting head that ejects the liquid in the pressure chamber as liquid droplets by causing pressure fluctuations include an ink jet recording head used in an image recording apparatus such as an ink jet recording apparatus (hereinafter simply referred to as a printer). (Hereinafter simply referred to as a recording head), a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an organic EL (Electro Luminescence) display, an electrode material ejecting head used for forming an electrode such as an FED (surface emitting display) And a bio-organic substance ejecting head used for manufacturing a biochip (biochemical element).

  For example, in the recording head as described above, as shown in FIG. 6, an ink introduction needle 92 which is a kind of liquid introduction needle is inserted into an ink cartridge 91 as a liquid storage member in which liquid ink is sealed. The ink in the ink cartridge 91 passes through the ink flow path in the recording head 93 (a series of flow paths from the ink introduction needle 92 to the nozzle 99 through the case flow path 95, the reservoir 96, the ink supply port 97, and the pressure chamber 98). ). Thereby, the ink flow path is filled with ink. The ink in the pressure chamber 98 is ejected as droplets from the nozzle 99 by the operation of a pressure generating means (not shown).

  However, vibration (oscillation) of the ink cartridge 91 that occurs when the ink introduction needle 92 is inserted into the ink cartridge 91 (the broken line shown in FIG. 6A represents the oscillation of the ink cartridge 91), ink, An impact may be applied to the ink introduction needle 92 due to an external action (impact) applied to the ink cartridge 91 after the introduction needle 92 is inserted into the ink cartridge 91 (white arrow in FIG. 6A). The pressure due to this impact propagates to the ink in the ink introduction needle 92 and further propagates to the nozzle 99 via the ink flow path (white arrow in FIG. 6B), thereby causing the meniscus formed on the nozzle 99. 100 could be destroyed. As a result, ink ejection (ejection) failure may occur.

  In addition, the ink flow path is ideally filled with ink, but gas may enter the ink flow path when the ink cartridge is replaced. In order to prevent such problems, a filter that captures gas (bubbles) mixed in the ink in the ink flow path is arranged, and a gas recovery unit that collects bubbles in the upper chamber of the filter is partitioned by a permeation partition wall, A structure for collecting air bubbles through this permeation partition wall is disclosed (for example, see Patent Document 1). Moreover, according to this structure, the said impact can be relieved by forming a permeation | transmission partition wall with the member which has flexibility.

JP 2008-173961 A

  However, in the structure as described above, since the air bubbles are recovered through the permeation partition wall, the recovery efficiency is poor and the air bubbles in the ink flow path cannot be sufficiently eliminated. Further, the transmission partition wall could not obtain sufficient elasticity to mitigate the impact applied to the ink introduction needle, and could not sufficiently prevent the meniscus from being destroyed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to destroy a meniscus when an impact generated due to a swinging of a liquid storage member propagates liquid in a flow path. An object of the present invention is to provide a liquid ejecting head and a liquid ejecting apparatus that can suppress this and collect gas mixed in the liquid in the flow path.

The liquid ejecting head of the present invention has been proposed in order to achieve the above-described object, and the liquid is introduced into the pressure chamber side through the liquid flow path from the liquid introducing portion into which the liquid is introduced, and the pressure generating means is operated. A liquid ejecting head capable of ejecting liquid in a pressure chamber as droplets from a nozzle,
Forming a filter chamber provided with a filter for filtering the liquid in the liquid flow path inside the liquid introduction part,
A gas chamber storing gas therein is formed above the filter in the gravity direction above the filter, and the gas chamber communicates with the filter chamber.

  According to this configuration, vibration (oscillation) of the liquid storage member that occurs when the liquid storage member is inserted into the liquid introduction unit, or external application applied to the liquid storage member after the liquid storage member is inserted into the liquid introduction unit Even if a sudden pressure fluctuation occurs in the liquid inlet due to an action (impact), the pressure fluctuation can be reduced (absorbed) by the gas stored in the gas chamber, and this pressure fluctuation can be propagated to the nozzle. Can be suppressed. Further, since pressure fluctuation can be alleviated by gas directly without using a flexible film or the like, it is possible to cope with more rapid pressure fluctuation. Thereby, it is possible to prevent the meniscus formed in the nozzle from being broken, and it is possible to prevent a liquid ejection (discharge) failure. In addition, since the gas chamber is formed above the filter in the direction of gravity, air bubbles that have been captured by the filter and then lifted by buoyancy can be accommodated in the gas chamber, and the air bubbles mixed into the liquid can be reliably recovered. Can do. And since the gas chamber was formed in the liquid introduction part into which the liquid is introduced, the gas chamber can be easily formed as compared with the case where the gas chamber communicating with the internal liquid flow path is formed, and the shape of the gas chamber There is also a high degree of freedom in size.

The said structure WHEREIN: It is desirable to employ | adopt the structure provided with the gas amount adjustment means which can adjust the quantity of the gas in this gas chamber in the said gas chamber.
According to this structure, it can prevent that the gas in a gas chamber reduces by melt | dissolving in a liquid etc., and an impact relaxation effect reduces. Further, it is possible to prevent the bubbles mixed in the liquid from exceeding the allowable capacity of the gas chamber and overflowing from the gas chamber.

In each of the above configurations, the filter chamber has an upstream communication port that is a communication port with a flow channel upstream of the filter chamber, and the inner method is gradually expanded from the upstream communication port toward the filter. It is desirable to adopt a configuration in which an enlarged portion is formed.
According to this configuration, some of the bubbles caught by the filter can be guided upward along the inner surface of the enlarged portion, and the bubbles are guided to the gas chamber opened there, and the bubbles are accommodated in the gas chamber. Can be made easier. Moreover, the filter can be made relatively large, and the flow path resistance of the liquid passing therethrough can be lowered. Thereby, a liquid can be poured smoothly.

In addition, the filter chamber has a downstream communication port that communicates with a flow path downstream from the filter chamber,
The opening center of the downstream communication port is disposed at a position away from the opening center of the upstream communication port in a plan view with respect to the filter,
The gas chamber preferably communicates with an inner surface of the enlarged portion between the upstream communication port and the downstream communication port.
According to this configuration, the liquid can flow along the inner surface of the enlarged portion, and the gas chamber communicates with a part of the upper surface on the inner surface, so that the liquid and bubbles can easily pass under the bubble chamber. It is possible to make it easier to accommodate the bubbles that are swept away by the buoyancy in the gas chamber.

Furthermore, it is desirable that the gas chamber communicates with a portion upstream of the filter in the enlarged portion.
According to this configuration, since the bubbles can be collected on the upstream side, the bubbles can be more easily accommodated in the gas chamber.

The liquid ejecting apparatus of the present invention can introduce the liquid into the pressure chamber through the liquid flow path from the liquid introducing portion into which the liquid is introduced, and eject the liquid in the pressure chamber as droplets from the nozzle by the operation of the pressure generating means. A liquid ejecting apparatus,
Forming a filter chamber provided with a filter for filtering the liquid in the liquid flow path inside the liquid introduction part,
A gas chamber storing gas therein is formed above the filter in the gravity direction above the filter, and the gas chamber communicates with the filter chamber.

It is a perspective view of a printer. FIG. 3 is a cross-sectional view of the recording head in a state where an ink cartridge is mounted. FIG. 3 is a cross-sectional view of a recording head main body. (A) Enlarged sectional view of the ink introduction needle, (b) Enlarged sectional view of the gas chamber. It is an expanded sectional view of the ink introduction needle in the second embodiment. It is a figure explaining the conventional recording head, (a) The schematic diagram of the flow path in a recording head, (b) The area A enlarged view.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In this embodiment, an ink jet recording head (hereinafter referred to as a recording head) will be described as an example of a liquid ejecting head.

  The printer 1 has a recording head 2 attached thereto and a carriage 4 to which an ink cartridge 3 which is a kind of liquid storage member is detachably attached, a platen 5 disposed below the recording head 2, and a recording of the carriage 4. A carriage moving mechanism 7 for moving the paper 6 (a kind of landing target on which the liquid ejected from the nozzle 21 is landed), and paper feeding for transporting the recording paper 6 in a paper feeding direction that is orthogonal to the paper width direction A mechanism 8 or the like is provided. Here, the paper width direction is the main scanning direction (reciprocating direction of the recording head 2), and the paper feeding direction is the sub-scanning direction (that is, the direction orthogonal to the scanning direction of the recording head 2).

  The carriage 4 is attached while being supported by a guide rod 9 installed in the main scanning direction, and is configured to move in the main scanning direction along the guide rod 9 by the operation of the carriage moving mechanism 7. ing. The position of the carriage 4 in the main scanning direction is detected by the linear encoder 10, and a detection signal is transmitted as position information to a control unit (not shown). Thus, the control unit can control the recording operation (jetting operation) and the like by the recording head 2 while recognizing the scanning position of the carriage 4 (recording head 2) based on the position information from the linear encoder 10.

  Next, the configuration of the recording head 2 will be described. Here, FIG. 2 is a cross-sectional view of the recording head 2 with the ink cartridge 3 attached, and FIG. 3 is a cross-sectional view of the recording head main body 15. The illustrated recording head 2 includes an introduction needle holder 14 having an ink introduction needle 12 (corresponding to a liquid introduction portion in the present invention) in a cartridge mounting portion 13, and a recording head main body 15 connected to the lower portion of the introduction needle holder 14. It is equipped with. Note that FIG. 2 schematically shows the recording head 2 in order to show the flow path from the ink cartridge 3 to the nozzle 21 in an easy-to-understand manner, so that the shape, positional relationship, size, etc. of each part are actually May be different.

  The introduction needle holder 14 is made of, for example, a synthetic resin, and a plurality of cartridge mounting portions 13 are provided on the upper surface thereof as shown in FIG. An ink introduction needle 12 is attached to each cartridge mounting portion 13 with the tip protruding upward. Inside the ink introduction needle 12, an introduction needle flow path 18 provided with a filter 17 for filtering ink and a gas chamber 16 communicating with the introduction needle flow path 18 are formed. The detailed configuration of the ink introduction needle 12 will be described later. In addition, these cartridge mounting portions 13 are mounted with ink cartridges 3 that store various inks (for example, cyan ink, magenta ink, yellow ink, and black ink). When the ink cartridge 3 is mounted on the cartridge mounting portion 13, the ink introduction needle 12 is inserted into the ink cartridge 3. Thereby, the ink storage space 3a in the ink cartridge 3 and the ink flow path in the recording head 2 communicate with each other via the introduction needle flow path 18, and the ink stored in the ink storage space 3a is transferred to the recording head 2. Introduced in. The ink cartridge 3 is not limited to the type that is mounted on the carriage 4 as in the present embodiment, but is the type that is mounted on the housing side of the printer 1 and supplies ink to the recording head 2 side through the ink supply tube. It is also possible to do.

  A plurality of tubular flow path forming tubes 19 are formed on the lower surface of the ink introduction needle 12 on the side opposite to the cartridge mounting portion 13 so as to correspond to the plurality of ink introduction needles 12 toward the recording head main body 15. Has been. Inside the flow path forming pipe 19, a communication flow path 19 a is formed which communicates with the introduction needle flow path 18 on the upstream side and communicates with a case flow path 26 of the head case 24 described later on the downstream side. In the present embodiment, the communication channel 19 a is inclined in the sub-scanning direction and the main scanning direction toward the case channel 26.

  As shown in FIG. 3, the recording head main body 15 includes a flow path unit 22 that forms an ink flow path that communicates with the nozzles 21, a vibrator unit 23 that includes pressure generation means that generates pressure fluctuations in the flow path, The head case 24 is provided with the child vibrator unit 23 therein.

  The head case 24 is a hollow box-like member, and the introduction needle holder 14 is mounted on the upper surface thereof. A flow path unit 22 is fixed to the lower surface opposite to the introduction needle holder 14 with a nozzle plate 28 (described later) exposed. Further, inside the head case 24, an accommodation space 25 for accommodating the transducer unit 23, a case flow path 26 for supplying ink from the upstream side (introduction needle holder 14 side) to the reservoir 32, and Are formed through the height direction. A plurality of case passages 26 are formed corresponding to the plurality of reservoirs 32, and the upper ends thereof communicate with the reservoirs 32 via a communication passage 19a and the lower ends thereof via an ink introduction port 37 (described later), respectively. ing.

  Next, the flow path unit 22 will be described. The flow path unit 22 is a thin plate-like member attached to the lower side (recording paper 6 side) of the head case 24. The flow path unit 22 includes a nozzle plate 28, a flow path forming substrate 29, and a vibration plate 30. The nozzle plate 28 is on one surface of the flow path forming substrate 29, and the vibration plate 30 is opposite to the nozzle plate 28. It is configured by arranging and laminating each other on the other surface of the flow path forming substrate 29 on the side, and integrating them by adhesion or the like.

  The nozzle plate 28 disposed on the bottom surface of the recording head 2 is a thin metal plate in which a plurality of nozzles 21 are opened along the main scanning direction at a pitch (for example, 180 dpi) corresponding to the dot formation density. Further, the nozzle 21 is formed so that the axis is perpendicular to the nozzle plate 28 and has a constant inner diameter, and from the flow path forming substrate 29 side to the opposite side of the flow path forming substrate 29 (recording paper 6 And a tapered portion whose inner diameter is reduced toward the side. One end of the taper portion opens in the surface of the nozzle plate 28 on the flow path forming substrate 29 side, and the other end of the taper portion is located in the middle of the nozzle plate 28 thickness direction. One end of the straight portion communicates with the other end of the taper portion, and the other end of the straight portion opens on the surface of the nozzle plate 28 on the recording paper 6 side. And the meniscus is formed in this straight part. Further, in the present embodiment, for example, 180 nozzles 21 are opened in a row, and these nozzles 21 constitute a nozzle row.

  The flow path forming substrate 29 is a plate-like member that forms a series of flow paths including a reservoir 32, an ink supply port 33, and a pressure chamber 34. Specifically, the flow path forming substrate 29 is formed with a plurality of empty portions corresponding to the respective nozzles 21 in a state where the pressure chambers 34 are partitioned by partition walls, and the empty portions serving as the ink supply ports 33 and the reservoirs 32. It is the plate-shaped member which formed. The flow path forming substrate 29 of the present embodiment is manufactured by etching a silicon wafer. The pressure chamber 34 is formed as a long and narrow chamber in a direction perpendicular to the nozzle row direction, and the ink supply port 33 is formed as a narrowed portion having a narrow channel width communicating between the pressure chamber 34 and the reservoir 32. Has been. The reservoir 32 is a chamber for supplying ink stored in the ink cartridge 3 to each pressure chamber 34, and communicates with the corresponding pressure chamber 34 through the ink supply port 33. In this embodiment, from the introduction needle channel 18 of the ink introduction needle 12 to the pressure chamber 34 via the communication channel 19a, the case channel 26, the ink introduction port 37, the reservoir 32, and the ink supply port 33. A series of ink flow paths corresponds to the liquid flow path of the present invention.

  The diaphragm 30 is a composite plate material having a double structure in which a resin film 36 such as PPS (polyphenylene sulfide) is laminated on a metal support plate 35 such as stainless steel. A plurality of ink inlets 37 penetrating in the vertical direction are provided in the diaphragm 30 corresponding to the respective reservoirs 32, and the reservoirs 32 and the case flow paths 26 are connected. In addition, a portion corresponding to the pressure chamber 34 of the diaphragm 30 has a diaphragm portion 38 for sealing one opening surface of the pressure chamber 34 and changing the volume of the pressure chamber 34. The diaphragm portion 38 is an island portion 39 for etching the portion of the support plate 35 corresponding to the pressure chamber 34 and removing the portion in an annular shape to join the tip of the free end portion of the piezoelectric vibrator 44 described later. It is comprised by forming. Similar to the planar shape of the pressure chamber 34, the island portion 39 has a block shape elongated in a direction orthogonal to the nozzle row direction, and the resin film 36 around the island portion 39 functions as an elastic film. Furthermore, a compliance portion 40 that seals one opening surface of the reservoir 32 is formed in a portion corresponding to the reservoir 32 of the vibration plate 30. That is, in the compliance portion 40, the support plate 35 is removed by etching according to the opening shape of the reservoir 32, and only the resin film 36 is formed.

  Next, the vibrator unit 23 will be described. The vibrator unit 23 includes a piezoelectric vibrator group 42 composed of a plurality of piezoelectric vibrators 44 (a kind of pressure generating means), a flexible cable 43 (wiring member), and the like. The piezoelectric vibrators 44 constituting the piezoelectric vibrator group 42 are formed in a comb-teeth shape elongated in the vertical direction, and are cut into extremely thin widths of about several tens of μm. The piezoelectric vibrator 44 is configured as a longitudinal vibration type piezoelectric vibrator 44 that can expand and contract in the vertical direction. Each piezoelectric vibrator 44 is fixed in a so-called cantilever state by joining a fixed end portion onto a fixed plate 45 so that the free end portion protrudes outward from the tip edge of the fixed plate 45. Then, the distal end of the free end portion of each piezoelectric vibrator 44 is joined to the island portion 39 constituting the diaphragm portion 38 in the flow path unit 22 as described above. The fixed plate 45 that supports each piezoelectric vibrator 44 is made of a metal plate material having rigidity capable of receiving a reaction force from the piezoelectric vibrator 44. In this embodiment, it is made of a stainless steel plate having a thickness of about 1 mm. Further, the flexible cable 43 is electrically connected to the piezoelectric vibrator 44 at one side of the fixed end opposite to the fixed plate 45 and connected to a control board (not shown) at the other end. Accordingly, a signal from the control unit can be sent to the piezoelectric vibrator 44 via the control board and the flexible cable 43, and the expansion and contraction of the piezoelectric vibrator 44 is controlled.

  In the recording head 2 configured as described above, the tip surface of the piezoelectric vibrator 44 is joined to the island portion 39, so that the volume of the pressure chamber 34 is changed by expanding and contracting the free end of the piezoelectric vibrator 44. Can be made. As the volume changes, pressure fluctuations occur in the ink in the pressure chamber 34. The recording head 2 uses this pressure fluctuation to eject (discharge) ink in the pressure chamber 34 from the nozzle 21 as ink droplets.

  Next, the configuration of the ink introduction needle 12 will be described. As shown in FIG. 4A, the ink introduction needle 12 is a member having an internal space as an introduction needle flow path 18 and a gas chamber 16. In the present embodiment, the hollow needle-like needle member 47 attached to the introduction needle holder 14 and the lower portion thereof (the upper surface of the introduction needle holder 14 corresponding to the needle member 47) are integrated with each other. Is forming. The needle member 47 has an upstream filter chamber 52 (described later) inside, and has a substantially conical diameter-enlarged portion 47a that is expanded (enlarged) toward the downstream side (filter 17 side). Equivalent), a cylindrical portion 47b formed at the upper portion of the enlarged diameter portion 47a, a conical pointed portion 47c formed in a tapered shape at the tip of the cylindrical portion 47b, and the upstream filter chamber 52 (that is, the filter chamber 51). A cubic gas chamber portion 47d having a gas chamber 16 communicating with the filter 17 above the filter 17), and the tip 47c communicates the outside and the inside of the ink introduction needle 12 with each other. A plurality of introduction holes 48 for establishing communication between the ink storage space 3a and a through passage 49 described later are provided. Further, a through passage 49 is formed in the pointed portion 47 c and the cylindrical portion 47 b of the needle member 47 so that the upper end portion communicates with the lower end portion (downstream side) of the introduction hole 48.

  A filter chamber 51 including a filter 17 for filtering the ink in the introduction needle channel 18 to remove foreign matters, bubbles, and the like communicates with the lower end portion of the through passage 49. The filter 17 of the present embodiment is made of a metal flat mesh material having a fine mesh, and supplements gas (bubbles b) and other foreign matters in the ink passing therethrough. The filter chamber 51 includes an upstream filter chamber 52 in which an inner diameter (inner method) is gradually expanded (enlarged) from the upstream communication port 52 a that is a communication port with the through passage 49 toward the filter 17, and the filter 17 The inner diameter (inner method) was gradually reduced toward the downstream communication port 53a, which is located on the opposite side (downstream side) with the filter 17 and communicated with the communication channel 19a communicating with the lower end portion from the filter 17. A downstream filter chamber 53. As described above, a series of introduction needle flow paths 18 are constituted by the introduction hole 48, the through passage 49, the upstream filter chamber 52, and the downstream filter chamber 53 inside the ink introduction needle 12. Therefore, when the pointed end 47 c of the ink introduction needle 12 is inserted into the ink cartridge 3, the ink in the ink storage space 3 a is sent to the communication flow path 19 a through the introduction needle flow path 18. In the present embodiment, the through-channel 49 and the communication channel 19 a have the same opening center in plan view with respect to the filter 17.

  The lower portion of the gas chamber 16 communicates with the upstream portion of the upstream filter chamber 52 on the inner surface of the enlarged-diameter portion 47a. The ink is introduced from this communication port to fill the middle position with ink, and rises by buoyancy. The bubbles b in the ink thus collected are collected (accommodated) through the communication port. For this reason, the gas layer a is formed on the upper side in the gravity direction in the gas chamber 16. A gas amount adjusting mechanism 55 including a check valve 57, a pump 60, and a vent pipe 56 that can adjust the amount of gas in the gas layer a is provided on the ceiling surface (the upper surface in the direction of gravity) of the gas chamber 16. (Gas amount adjusting means in the present invention).

  As shown in FIG. 4 (b), the gas amount adjusting mechanism 55 of the present embodiment communicates with one side of the ceiling surface of the gas chamber 16 (the left side in FIG. 4 (b)) and is adjusted to a positive pressure. The pressure side vent pipe 56a communicates with the other side of the ceiling surface of the gas chamber 16 (the right side in FIG. 4 (b)), and the decompression side vent pipe 56b set to a negative pressure and the lower side of the pressurization side vent pipe 56a ( The first check valve 57a provided on the gas chamber 16 side), the second check valve 57b provided on the lower side (gas chamber 16 side) of the decompression side vent pipe 56b, and the specific gravity lighter than the ink, And a float 61 floating on the ink liquid surface (boundary surface with the gas layer a in the gas chamber 16). The first check valve 57a includes a first constricted portion 63 in which the width of the passage of the pressure side vent pipe 56a is narrowed, and a first lid portion 64 (blocking the first constricted portion 63 above the first constricted portion 63 ( And a first spring 65 (tensile spring) having one end fixed to the first lid portion 64 and the other end fixed to the float 61. The second check valve 57b includes a second constricted portion 67 in which the width of the passage of the decompression side vent pipe 56b is narrowed, and a second lid portion that closes the second constricted portion 67 below the second constricted portion 67. 68 (valve element) and a second spring 69 (compression spring) having one end fixed to the second lid 68 and the other end fixed to the float 61. Note that the pressurization side vent pipe 56a and the negative pressure side vent pipe each have a pump, and these pumps set the pressurization side vent pipe 56a to a positive pressure and the decompression side vent pipe 56b to a negative pressure, respectively.

  By configuring the gas amount adjusting mechanism 55 in this way, a change in the liquid level of the ink in the gas chamber 16, that is, a displacement (up or down) of the float 61 due to a change in the volume of the gas causes the first spring 65 or The first check valve 57a and the second check valve 57b can be opened and closed by being transmitted to the first lid portion 64 or the second lid portion 68 via the second spring 69. Hereinafter, this point will be described.

  When the amount of the gas layer a in the gas chamber 16 is within a certain range, as shown in FIG. 4B, the pressure side vent pipe 56a is at a positive pressure, and the urging force ( The first lid portion 64 is pressed toward the first constricted portion 63 side (downward arrow in FIG. 4B). Similarly, the pressure reducing side vent pipe 56b has a negative pressure, and an urging force (force to press upward) by the second spring 69 acts, so that the second lid portion 68 is pressed toward the second constricted portion 67 side. (Upward arrow in FIG. 4B). For this reason, the 1st cover part 64 and the 2nd cover part 68 contact | abut to the edge of the 1st constriction part 63 and the 2nd constriction part 67, respectively. Thereby, the passage of gas in the pressurizing side vent pipe 56a and the decompression side vent pipe 56b is blocked, and both are closed. On the other hand, when the bubbles b mixed in the ink in the introduction needle channel 18 (upstream filter chamber 52) are introduced into the gas chamber 16, the amount of the gas layer a in the gas chamber 16 gradually increases. As a result, the ink level in the gas chamber 16 is lowered. Along with this, when the float 61 descends against the urging force of the first spring 65, the second lid portion 68 fixed to the second spring 69 descends, whereby the second lid portion 68 becomes the second constriction. The second check valve 57b is opened away from the edge of the portion 67. In this state, since the decompression side vent pipe 56b is set to a negative pressure, the gas in the gas chamber 16 is discharged. Along with this, the liquid level rises and the float 61 also rises. As a result, the second lid portion 68 fixed to the second spring 69 rises, the second lid portion 68 contacts the edge of the second constricted portion 67, and the second check valve 57b returns to the closed state.

  In addition, when the amount of the gas layer a in the gas chamber 16 decreases due to the gas in the upstream filter chamber 52 being dissolved in the ink or being discharged outside from the wall surface of the gas chamber portion 47d, the gas As the amount of gas in the chamber 16 gradually decreases, the ink level in the gas chamber 16 rises. Along with this, when the float 61 rises against the urging force of the second spring 69, the first lid portion 64 fixed to the first spring 65 rises, whereby the first lid portion 64 becomes the first constriction. The first check valve 57a is opened away from the edge of the portion 63. In this state, since the pressurized side vent pipe 56a is set to a positive pressure, gas is introduced into the gas chamber 16. Along with this, the liquid level descends and the float 61 also descends. As a result, the first lid portion 64 fixed to the first spring 65 is lowered, the first lid portion 64 comes into contact with the edge of the first constricted portion 63, and the first check valve 57a returns to the closed state.

  As described above, the filter chamber 51 including the filter 17 for filtering the ink in the liquid flow path is formed inside the ink introduction needle 12, and the filter chamber 51 has a filter chamber 51 above the filter 17 in the gravity direction. Since the gas chamber 16 storing the gas is formed and the gas chamber 16 and the filter chamber 51 are communicated with each other, the vibration (oscillation) of the ink cartridge 3 generated when the ink cartridge 3 is inserted into the ink introduction needle 12. Even if a sudden pressure fluctuation occurs in the ink introduction needle 12 due to an external action (impact) applied to the ink cartridge 3 after the ink cartridge 3 is inserted into the ink introduction needle 12, it is stored in the gas chamber 16. The pressure fluctuation can be relaxed (absorbed) by the gas, and the propagation of the pressure fluctuation to the nozzle 21 can be suppressed. Further, since pressure fluctuation can be alleviated by gas directly without using a flexible film or the like, it is possible to cope with more rapid pressure fluctuation. Thereby, it is possible to prevent the meniscus formed in the nozzle 21 from being destroyed, and it is possible to prevent ink ejection (discharge) failure. In addition, since the gas chamber 16 is formed above the filter 17 in the direction of gravity, the bubbles b that have been lifted by buoyancy after being captured by the filter 17 can be accommodated in the gas chamber 16 and reliably mixed into the ink. The bubble b can be collected. Since the gas chamber 16 is formed in the ink introduction needle 12 into which ink is introduced, the gas chamber can be formed more easily than in the case where the gas chamber communicating with the internal liquid flow path is formed. The degree of freedom of shape and size is also high.

  Further, in this embodiment, the gas chamber 16 is provided with a gas amount adjusting mechanism capable of adjusting the amount of gas in the gas chamber 16, so that the gas in the gas chamber 16 is reduced by being dissolved in the ink or the like. It is possible to prevent the impact relaxation effect from decreasing. Further, it is possible to prevent the bubble b mixed in the ink from exceeding the allowable amount of the gas chamber 16 and overflowing from the gas chamber 16. Further, since the filter chamber 51 is formed with the enlarged diameter portion 47a having the inner diameter gradually enlarged from the upstream communication port 52a toward the filter 17, a part of the bubbles b caught by the filter 17 are expanded. The gas b can be guided upward along the inner surface of the gas, and the bubble b can be guided to the gas chamber 16 opened there, so that the bubble b can be easily accommodated in the gas chamber 16. Further, the filter 17 can be made relatively large, and the flow path resistance of the ink passing therethrough can be lowered. Thereby, ink can be smoothly flowed. Moreover, since the gas chamber 16 communicated with the upstream portion of the enlarged-diameter portion 47a relative to the filter 17, the air bubbles b can be collected on the upstream side, and the air bubbles b can be more easily accommodated in the gas chamber 16. can do.

  By the way, in the said 1st Embodiment, in the planar view with respect to the filter 17, although the opening center of the upstream communication port 52a and the opening center of the downstream communication port 53a were arrange | equalized, it is not restricted to this. For example, in the second embodiment shown in FIG. 5, the opening center of the upstream communication port 52 a is arranged at a position away from the opening center of the downstream communication port 53 a in a plan view with respect to the filter 17. Furthermore, in this embodiment, the through passage 49 is shifted to the opposite side (the side away from the nozzle 21) from the nozzle 21, and the communication channel 19a is shifted to the nozzle 21 side relatively in a direction perpendicular to the nozzle row. It is arranged. In addition, the upstream filter chamber 52 extends downward in the vertical direction (extending direction of the through passage 49) with the inner surface of one side end (left end in FIG. 5) aligned with the inner surface of the through passage 49, and The other surface is expanded toward the filter 17. On the other hand, the downstream filter chamber 53 extends downward in the vertical direction (extending direction of the communication channel 19a) with the inner surface of the other side end (right end in FIG. 5) aligned with the inner surface of the communication channel 19a. At the same time, the other surface is expanded toward the filter 17. For this reason, the upper surface of the enlarged diameter portion 47a is formed between the upstream communication port 52a and the downstream communication port 53a. The gas chamber 16 communicates with the upstream portion of the upstream filter chamber 52 in the enlarged diameter portion 47a. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

  In the second embodiment, since it is configured as described above, ink can flow along the inner surface of the enlarged diameter portion 47a. Then, by communicating the gas chamber 16 with the upper part of the inner surface along the ink flow, ink and bubbles easily pass under the bubble chamber 16, and the bubbles b swept away by the ink enter the gas chamber 16 by buoyancy. It can be easily accommodated.

  Further, the gas amount adjusting mechanism 55 is not limited to the above embodiment. Any configuration is possible as long as the amount of gas in the gas chamber can be adjusted. For example, a sensor for detecting the ink surface in the gas chamber is provided, and a check valve provided in the vent pipe is opened and closed according to a measurement value by the sensor, and a gas in the gas chamber is introduced by a pump provided in the vent pipe. You may comprise so that it may discharge | emit.

  In the above description, a recording head which is a kind of liquid ejecting head has been described as an example, but the present invention can also be applied to other liquid ejecting heads having a liquid introduction needle. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 3 ... Ink cartridge, 12 ... Ink introduction needle, 17 ... Filter, 18 ... Introduction needle flow path, 19a ... Communication flow path, 21 ... Nozzle, 26 ... Case flow path, 34 ... Pressure 48, introduction hole, 49 ... through passage, 51 ... filter chamber, 52 ... upstream filter chamber, 55 ... gas amount adjusting mechanism, 56 ... vent pipe, 57 ... check valve, 60 ... pump

Claims (6)

A liquid ejecting head capable of introducing a liquid from a liquid introducing portion into which a liquid is introduced to a pressure chamber through a liquid flow path, and ejecting the liquid in the pressure chamber as a droplet from a nozzle by operation of a pressure generating unit,
Forming a filter chamber provided with a filter for filtering the liquid in the liquid flow path inside the liquid introduction part,
A liquid ejecting head, wherein a gas chamber in which a gas is stored is formed above the filter in the gravity direction above the filter, and the gas chamber communicates with the filter chamber.   The liquid ejecting head according to claim 1, wherein the gas chamber includes gas amount adjusting means capable of adjusting an amount of gas in the gas chamber.   The filter chamber has an upstream communication port which is a communication port with a flow channel upstream from the filter chamber, and forms an enlarged portion in which an internal method is gradually expanded from the upstream communication port toward the filter. The liquid ejecting head according to claim 1, wherein the liquid ejecting head is provided. The filter chamber has a downstream communication port communicating with a flow channel downstream from the filter chamber,
The opening center of the downstream communication port is disposed at a position away from the opening center of the upstream communication port in a plan view with respect to the filter,
The liquid ejecting head according to claim 3, wherein the gas chamber communicates with an inner surface of the enlarged portion between the upstream communication port and the downstream communication port.   5. The liquid ejecting head according to claim 3, wherein the gas chamber communicates with a portion of the enlarged portion upstream of the filter. A liquid ejecting apparatus capable of introducing a liquid from a liquid introducing portion into which a liquid is introduced to a pressure chamber through a liquid flow path, and ejecting the liquid in the pressure chamber as a droplet from a nozzle by operation of a pressure generating unit,
Forming a filter chamber provided with a filter for filtering the liquid in the liquid flow path inside the liquid introduction part,
A liquid ejecting apparatus comprising: a gas chamber in which gas is stored inside the filter chamber above the filter in a direction of gravity; and the gas chamber and the filter chamber communicate with each other.

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