JP2008238414A - Liquid ejection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head which can restrain liquid consumption by decreasing the number of execution times of cleaning operation. <P>SOLUTION: In the recording head for introducing liquid in an ink cartridge to a pressure chamber through an ink introduction path 42 and ejecting a liquid drop from the nozzle opening by driving a piezoelectric vibrator, a portion 45 having the inside diameter enlarged as compared with other portion of the ink introduction path 42 is provided in the way thereof, a filter 18 is arranged in the enlarged diameter portion 45, and a flexible guide piece 48 is extended from the inner circumferential surface 47 of the ink introduction path 42 on the upstream side of the filter 18 toward the radial center O side of the ink introduction path 42. The guide piece 48 has resiliency for converting the tip portion 49 between a first state where the tip portion 49 is separated from the filter 18 to the upstream side and a second state where the guide piece 48 bends to bring the tip portion 49 close to the filter 18 thus regulating the downstream direction of the fluid depending on the current velocity of the fluid in the ink introduction path 42. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head such as an ink jet recording head, and more particularly to a liquid ejecting head that introduces liquid into a pressure chamber through a liquid inflow portion and ejects liquid droplets from a nozzle opening due to pressure fluctuation.

  Examples of the liquid ejecting head that ejects liquid droplets from the nozzle openings by causing pressure fluctuations in the liquid in the pressure chamber include, for example, an ink jet recording apparatus used in an image recording apparatus such as an ink jet recording apparatus (hereinafter simply referred to as a printer). Electrode material injection used to form electrodes such as heads (hereinafter simply referred to as recording heads), color material injection heads used in the manufacture of color filters such as liquid crystal displays, organic EL (Electro Luminescence) displays, FEDs (surface emission displays), etc. There are bio-organic matter ejecting heads used for manufacturing heads and biochips (biochemical elements).

  For example, in the recording head described above, an ink introduction needle opened at the tip of the ink introduction needle is inserted into an ink cartridge (hereinafter simply referred to as a cartridge) in which liquid ink is sealed. Ink in the cartridge is introduced into the pressure chamber of the recording head through the hole.

  In the recording head having the above-described configuration, it is ideal that the ink flow path from the ink introduction needle to the nozzle opening of the recording head is filled with ink. However, ink filling (initial filling) in the recording head or Bubbles may enter the ink flow path by replacing the ink cartridge or the like, and it is difficult to completely prevent this. Bubbles that have entered the ink flow path gradually grow and become large, and when some of the excessively grown bubbles move to the pressure chamber side due to the flow of ink, the bubbles absorb the pressure fluctuation during the discharge operation. There is a risk of causing problems such as pressure loss and insufficient supply of ink due to air bubbles blocking the flow path.

  In order to prevent such problems due to bubbles, the width of the ink supply flow path is increased and an elastic body is provided on the side wall of the filter chamber in which the filter is disposed. The elastic body is deformed inward when the pressure in the filter chamber is reduced. Thus, there has been proposed a recording head in which the flow path is reduced, thereby making it easier to discharge bubbles (see, for example, Patent Document 1). In addition, a recording head has been proposed that includes a pushing member that moves in the downflow direction by ink flow down and pushes out bubbles (for example, see Patent Document 2).

JP 2000-296622 A JP 2006-142816 A

  By the way, in this type of ink jet printer, a so-called cleaning operation is performed in which air bubbles in the ink introduction needle are forcibly sucked and discharged from the nozzle opening together with the ink every time the cartridge is replaced or a certain period of time elapses. . In this cleaning operation, the suction condition (suction force, suction time) is set to a condition that takes into consideration the bubble discharge performance. Specifically, the suction force is set so as to obtain a flow rate slightly higher than the flow rate necessary for the bubbles in the ink introduction needle to pass through the filter, and the bubbles are reliably removed from the recording head to the outside. Is set to the possible suction time.

  However, since there is no configuration in which any of the recording heads temporarily captures excessively grown bubbles while securing the flow path at the flow rate of ink for performing normal printing, the bubbles are flow paths. There was a risk of blocking. This necessitates frequent cleaning operations.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head capable of suppressing the consumption of liquid by reducing the number of executions of a cleaning operation.

In order to achieve the above object, a liquid ejecting head of the present invention is a liquid ejecting head that introduces liquid into a pressure chamber through a liquid inflow portion and ejects liquid droplets from a nozzle opening due to pressure fluctuation,
On the downstream side of the liquid inflow portion, an enlarged diameter portion that is larger than the inner diameter of the liquid inflow portion is provided,
Place a filter in the enlarged diameter part,
Extending a flexible guide piece from the inner peripheral surface of the liquid inflow portion upstream of the filter toward the diameter center side of the liquid inflow portion,
The guide piece has a first state in which a tip portion is spaced upstream of the filter, and a second state in which the tip portion is bent downstream and the tip portion is brought close to the filter to regulate a fluid flow direction. And converting according to the flow velocity of the fluid in the liquid inflow portion.

  According to the above configuration, the guide piece extends from the inner peripheral surface of the liquid inflow portion upstream of the filter toward the center of the diameter of the liquid inflow portion so as to have flexibility, and the tip portion is more than the filter. The first state separated to the upstream side and the second state bent to the downstream side to make the tip close to the filter and restrict the flow direction of the fluid are converted according to the flow velocity of the fluid in the liquid inflow portion. Therefore, when the flow rate of the fluid in the liquid inflow portion is low, the guide piece is in the first state, and the excessively grown bubbles are temporarily captured while securing a flow path in the space between the filter and the guide piece. This can prevent air bubbles from blocking the flow path. And when the flow velocity of the fluid in the liquid inflow portion is fast, the guide piece is in the second state, and the fluid that flows from the tip of the bent guide piece to the inner peripheral surface side (the back side of the guide piece) is regulated. The guide is guided to the center side of the filter rather than the outer peripheral edge side of the filter, and the center side of the filter is allowed to pass at a high speed, so that bubbles can be efficiently passed along with the liquid from the center side of the filter. Therefore, it is possible to reduce the number of executions of the cleaning operation and suppress the consumption of liquid.

  In the above-described configuration, the guide piece is converted into the first state in the flow velocity of the fluid when ejecting the droplet from the nozzle opening, and the fluid in the fluid inflow portion is forcibly discharged from the nozzle opening. It is desirable that the flow rate be converted to the second state.

  According to the above configuration, the guide piece can be converted between the first state and the second state by changing the flow rate of the fluid during normal printing and during the cleaning operation for discharging bubbles. it can. Therefore, when the cleaning operation is executed, the guide piece is in the second state, and the bubbles can be forcibly sucked and discharged from the nozzle opening together with the liquid.

  In the above-described configuration, it is desirable that the guide piece is configured to form at least a gap through which the liquid can pass between the guide piece and the inner peripheral surface of the liquid inflow portion in the first state.

  According to the above configuration, even when the flow rate of the fluid in the liquid inflow portion is slow (normal printing), even if bubbles grow to the extent that the bending of the guide piece is prevented, the guide piece and the inner peripheral surface of the liquid inflow portion It is possible to ensure an interval between the two as a flow path. Therefore, it is possible to prevent problems such as insufficient supply of ink due to air bubbles blocking the flow path.

In the above configuration, a plurality of the guide pieces are provided,
It is desirable that the guide pieces are arranged in a state in which at least a gap through which liquid can pass is formed in the first state.

  According to the above configuration, each guide piece bends downstream, so that the flow direction of the fluid can be concentrated and guided to the center side of the filter. Further, when the flow velocity of the fluid in the liquid inflow portion is slow (normal printing), even if bubbles grow to the extent that the bending of the guide pieces is prevented, the interval between the guide pieces can be ensured as a flow path. Therefore, it is possible to prevent problems such as insufficient supply of ink due to air bubbles blocking the flow path.

  The said structure WHEREIN: It is desirable to set it as the structure by which the said guide piece is arrange | positioned in the upstream edge part of the said enlarged diameter part.

  According to the above configuration, since the guide piece is disposed at the upstream end of the enlarged diameter portion, when the flow rate of the fluid in the liquid inflow portion is high (cleaning operation), the fluid flowing into the enlarged diameter portion It is possible to suppress the flow around the circumferential surface. Therefore, since the fluid passes through the center side of the filter at a high speed, the bubbles can be efficiently passed through the filter together with the liquid. In addition, since the bubbles can be retained in the enlarged diameter portion that is larger in diameter than the liquid inflow portion, it is possible to prevent the flow path from being blocked by the bubbles.

  In the above configuration, it is desirable that the guide piece is in contact with the upstream surface of the filter in the second state.

  According to the above configuration, when the guide piece is in the second state, the tip end portion contacts the upstream surface of the filter, and therefore, along the surface on the radial center side (the front side of the guide piece) of the liquid inflow portion of the guide piece. Is prevented from flowing into the space between the back surface and the inner peripheral surface of the bent guide piece, and the fluid can pass through the center side of the filter at a high speed.

  In the above-described configuration, it is desirable that the guide piece is in contact with a position closer to the center side than the outer peripheral edge of the upstream surface of the filter to intensively guide the fluid from the upstream side to the upstream surface of the filter.

  According to the above configuration, the bent guide piece comes into contact with a position closer to the center side than the outer peripheral edge on the upstream surface of the filter, so the space between the back side surface of the bent guide piece and the inner peripheral surface of the liquid inflow portion. By preventing the fluid from flowing into the filter and reducing the flow path width on the upstream surface of the filter, the fluid can be passed through the center of the filter at high speed.

  In the above-described configuration, it is desirable that a guide auxiliary member having a guide channel through which fluid can pass is disposed on the upstream surface of the filter.

  According to the above configuration, since the guide auxiliary member having the guide flow path through which the fluid can pass is disposed on the upstream surface of the filter, the guide auxiliary member serves as a wall to increase the flow path width of the upstream surface of the filter. Narrow. And since the guidance auxiliary member regulates the flow direction of the fluid together with the guide piece, the fluid can be intensively guided to a part of the filter, and the bubbles can be efficiently passed through the filter together with the liquid.

  In the above configuration, it is desirable that an inner diameter of the guide channel is set smaller than a diameter of the filter.

  According to the above configuration, the fluid that passes through the filter is divided into the fluid that has passed through the guide flow path and the fluid that has passed between the guide auxiliary member and the inner peripheral surface. Both the path and the flow path for temporarily capturing bubbles can be secured. Therefore, it is possible to prevent problems such as insufficient supply of ink due to the filter being blocked by bubbles.

  In the above-described configuration, it is desirable that the guide piece bends with a tip portion directed toward the guide channel of the guide auxiliary member in the second state to guide fluid from the upstream side to the guide channel. Further, when the guide piece is bent, it is desirable that the guide piece comes into contact with the inner surface of the guide auxiliary member.

  According to the above configuration, the guide piece bends toward the guide flow path of the guide auxiliary member in the second state and guides the fluid from the upstream to the guide flow path. Can be reliably guided.

  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 “recording head”) will be described as an example of the liquid ejecting head.

  FIG. 1 is a perspective view of an ink jet recording apparatus. First, a schematic configuration of an ink jet recording apparatus (hereinafter referred to as a printer) equipped with a recording head will be described with reference to FIG. The illustrated printer 1 is an apparatus that records an image or the like by discharging liquid ink onto the surface of a recording medium (landing target) 2 such as recording paper. The printer 1 includes a recording head 3 for ejecting ink (corresponding to a kind of liquid ejecting head in the present invention), a carriage 4 to which the recording head 3 is attached, and a carriage 4 in the main scanning direction (reference numeral X in FIG. 1). And a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction (a direction perpendicular to the main scanning direction, indicated by a symbol Y in FIG. 1). Here, the ink is a kind of liquid of the present invention, and is stored in the ink cartridge 7. The ink cartridge 7 is detachably attached to the recording head 3.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Therefore, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction X (width direction of the recording paper 2).

  A capping mechanism 12 is disposed at a home position that is a non-recording area of the printer 1. The capping mechanism 12 has a tray-like cap member 11 that can be in contact with a later-described nozzle forming surface (nozzle plate 25 / see FIG. 2) of the recording head 3. In the capping mechanism 12, the space in the cap member 11 functions as a sealing empty portion, and the nozzle opening 26 (see FIG. 2) of the recording head 3 faces the nozzle forming surface in the sealing empty portion. It is configured to be possible. Further, a pump unit 13 is connected to the capping mechanism 12, and the inside of the sealed empty space can be made negative pressure by the operation of the pump unit 13. When the pump unit 13 is operated 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 bubbles in the recording head 3 are sucked from the nozzle opening 26 and the cap member. 11 is discharged into the sealed space. That is, the capping mechanism 12 is configured to perform an operation for forcibly sucking and discharging ink and bubbles in the recording head 3 (hereinafter referred to as a cleaning operation). Details of this cleaning operation will be described later.

  Next, the configuration of the recording head 3 will be described. 2 is a schematic perspective view of the recording head 3 attached to the carriage 4. FIG. 3 is a plan view of the recording head 3. FIG. The illustrated recording head 3 is schematically configured from a cartridge base 15 (hereinafter referred to as “base”), a head case 16, a flow path unit 17, a vibrator unit 22, and the like.

  The base 15 is molded from, for example, a synthetic resin, and as shown in FIG. 3, a plurality of compartments 14 (liquid storage member mounting portions) are provided on the upper surface thereof. An ink introduction needle 19 is attached to each compartment 14 with a filter 18 interposed. The ink cartridges 7 are mounted in these compartments 14. That is, the ink cartridge 7 is mounted in a state of being positioned on the base 15. The details of the ink cartridge 7 and the ink introduction needle 19 will be described later.

  As shown in FIG. 2, a circuit board 20 is attached to the other surface of the base 15 opposite to the section 14. The circuit board 20 includes, for example, a drive circuit for controlling supply of a drive signal to a piezoelectric vibrator 29 (see FIG. 5) to be described later, a connector for connection to the printer body side, and a through hole for supplying ink. Etc. And this circuit board 20 is attached to the base 15 via the sheet | seat member 21 which functions as packing.

  The head case 16 is fixed to the base 15 and is a casing for housing a vibrator unit 22 having a piezoelectric vibrator 29 described later. For this reason, the housing case 32 (see FIG. 5) capable of housing the transducer unit 22 is formed in the head case 16. The vibrator unit 22 is inserted into the housing space 32 and fixed by bonding or the like. And the flow path unit 17 is being fixed to the front end surface on the opposite side to the attachment surface of the base 15 of the head case 16 with the adhesive agent.

  The flow path unit 17 is manufactured by joining and integrating with the adhesive etc. in the state which laminated | stacked the elastic board 23, the flow path formation board | substrate 24, and the nozzle plate 25. FIG.

  The nozzle plate 25 is a member made of, for example, a thin plate made of stainless steel, and fine nozzle openings 26 are formed in a row in the nozzle plate 25 at a pitch corresponding to the dot formation density of the printer 1.

  A head cover 27 is attached to the front end portion of the head case 16 so as to surround the periphery of the nozzle plate 25 from the outside. The head cover 27 is made of, for example, a metal thin plate member. The head cover 27 has a function of protecting the front end portions of the flow path unit 17 and the head case 16 and preventing the nozzle plate 25 from being charged.

  FIG. 5 is a cross-sectional view of the main part of the recording head 3. The vibrator unit 22 supplies a drive signal from the circuit board 20 to the piezoelectric vibrator group 30 as pressure generating means, a fixing plate 31 to which the piezoelectric vibrator group 30 is joined, and the piezoelectric vibrator group 30. For example, a flexible cable (not shown). The piezoelectric vibrator group 30 of the present embodiment includes a plurality of piezoelectric vibrators 29 arranged in a comb shape. Each piezoelectric vibrator 29 has a fixed end joined on the fixed plate 31, and a free end protruding outside the front end surface of the fixed plate 31. That is, each piezoelectric vibrator 29 is mounted on the fixed plate 31 in a so-called cantilever state. The fixing plate 31 that supports each piezoelectric vibrator 29 is made of, for example, stainless steel having a thickness of about 1 mm. In addition to the piezoelectric vibrator, an electrostatic actuator, a magnetostrictive element, a heating element, or the like can be used as the pressure generating means.

  Inside the head case 16, an accommodation empty portion 32 that can accommodate the vibrator unit 22 is formed in a state where the height direction of the head case 16 is penetrated. The vibrator unit 22 is housed and fixed in the housing space 32 by bonding the back surface of the fixing plate 31 to the inner wall surface of the case that defines the housing space 32.

  A plurality of flow path forming substrates 24 are formed corresponding to the respective nozzle openings 26 in a state in which empty portions that become common ink chambers 33, groove portions that become ink supply ports 34, and empty portions that become pressure chambers 35 are partitioned by partition walls. It is a plate-shaped member. The flow path forming substrate 24 is produced, for example, by etching a silicon wafer. The pressure chamber 35 is formed as a long and narrow chamber in a direction perpendicular to the direction in which the nozzle openings 26 are arranged (nozzle row direction). The common ink chamber 33 communicates with an ink introduction path 42 (see FIG. 6), which will be described later, of the ink introduction needle 19 via an ink communication path 37 formed so as to penetrate the height direction of the head case 16. This is a chamber into which ink stored in the cartridge 7 is introduced. The ink introduced into the common ink chamber 33 is supplied to each pressure chamber 35 through the ink supply port 34.

  The elastic plate 23 is a composite plate material having a double structure in which an elastic film is laminated on a metal support plate such as stainless steel. An island portion 36 for joining the tip of the free end portion of the piezoelectric vibrator 29 is formed at a portion corresponding to the pressure chamber 35 of the elastic plate 23, and this portion functions as a diaphragm portion. Further, the elastic plate 23 seals one opening surface of the empty portion that becomes the common ink chamber 33, and also functions as a compliance portion. Only the elastic film is used for the portion functioning as the compliance portion.

  In the recording head 3, when the piezoelectric vibrator 29 is expanded and contracted in the element longitudinal direction, the island portion 36 moves in a direction toward or away from the pressure chamber 35. As a result, the volume of the pressure chamber 35 changes, and the pressure in the ink in the pressure chamber 35 varies. An ink droplet (a type of droplet) is ejected from the nozzle opening 26 due to the pressure fluctuation.

  Next, the ink cartridge 7 will be described. The ink cartridge 7 is a member that stores ink to be supplied to the recording head 3. The printer 1 of the present embodiment is configured to be able to eject eight types of inks, specifically, a total of eight colors of yellow, magenta, cyan, and the like, and each ink is individually supplied to the recording head 3. A total of eight ink cartridges 7 are mounted. A needle insertion opening (not shown) is provided on the bottom surface of each ink cartridge 7. This needle insertion opening is a portion into which the ink introduction needle 19 is inserted. At the time of shipment from the factory, the needle insertion port (not shown) is sealed with a film (not shown) to prevent air from entering the cartridge. This is because the ink in the ink cartridge 7 is stored in a deaerated (negative pressure) state, so that this deaerated state is maintained until just before use.

  Next, the configuration of the ink introduction needle 19 inserted into the ink cartridge 7 will be described. 6 is a sectional view of the ink introduction needle 19 in the needle longitudinal direction, and FIG. 7 is a sectional view taken along the line VII-VII in FIG. The ink introduction needle 19 is a hollow needle having an internal space as an ink introduction path 42 (corresponding to a liquid inflow portion in the present invention), and a conical pointed portion 43 formed in a tapered shape, A cylindrical straight portion 44 continuously formed on the downstream side, and a diameter-increased portion 45 formed continuously on the downstream side of the straight portion 44 and having an inner diameter larger than the inner diameter of the straight portion 44. It is comprised by. In the present embodiment, an ink introduction hole 46 that communicates the outside (external space) of the introduction needle and the ink introduction path 42 is formed in the tip portion 43. The enlarged diameter portion 45 is formed in a tapered shape that gradually increases in diameter from the upstream side (straight portion 44 side) to the downstream side (needle root side). Further, a plurality of plate-like guide pieces 48 protrude from the inner peripheral surface 47 of the enlarged diameter portion 45. The details of the guide piece 48 will be described later.

  The ink introduction needle 19 is attached to the base 15 by ultrasonic welding, for example, with the filter 18 interposed. As a result, the ink introduction path 42 of the ink introduction needle 19 and the ink communication path 37 on the head case 16 side communicate with each other.

  When the ink cartridge 7 is mounted on the base 15, the ink introduction needle 19 is inserted into a needle insertion port (not shown) of the ink cartridge 7, and the internal space (ink storage portion) of the ink cartridge 7 and the ink introduction needle 19 are inserted. The ink introduction path 42 communicates with the inside through an ink introduction hole 46. The ink stored in the ink cartridge 7 is introduced into the ink introduction path 42 through the ink introduction hole 46 and supplied to the common ink chamber 33 on the recording head 3 side through the ink communication path 37.

  Incidentally, as described above, since the internal space of the ink cartridge 7 is in a deaerated state, a valve (not shown) in which the tip of the ink introduction needle 19 is provided in a needle insertion port (not shown) is provided. When pushed up, air enters the boundary between the ink cartridge 7 and the ink introduction needle 19. When the ink is filled into the recording head 3, the air may be introduced into the ink introduction path 42 together with the ink as bubbles. Then, in the ink introduction path 42, the bubbles gradually combine with time and grow into larger bubbles. Largely grown bubbles may block the ink introduction path 42 and the filter 18, which may cause problems such as ink droplets not being ejected. For this reason, the printer 1 performs a cleaning operation using the capping mechanism 12 every elapse of a certain period of time so as to discharge bubbles that have grown greatly.

  In this cleaning operation, as described above, the pump unit 13 is operated while the cap member 11 is in close contact with the nozzle formation surface (nozzle plate 25), and is several times that during normal ink ejection (recording operation). A flow of ink having a flow velocity (a fluid including both ink and bubbles, which corresponds to a kind of fluid in the present invention) is generated in the recording head 3, and the bubbles in the ink introduction path 42 are placed on the ink flow. Then, it is discharged out of the recording head 3. The suction conditions (suction force, suction time) of the pump unit 13 at this time are set to conditions that take into account the bubble discharge properties. From the viewpoint of reducing the ink consumed in this cleaning operation as much as possible, during normal recording operation, air bubbles are temporarily captured while securing a flow path, and during the cleaning operation, a part of the filter 18 is passed. Only the ink flow rate needs to be increased, and it is desirable to allow air bubbles to pass through a portion of the filter 18.

  In the present embodiment, the guide piece 48 has flexibility, and as shown in FIGS. 6 and 7, the guide piece 48 is provided at the upstream end portion (end portion away from the filter 18) 51 of the enlarged diameter portion 45. It is arranged. The guide piece 48 extends from the inner peripheral surface 47 toward the diameter center O side of the ink introduction path 42. That is, the guide piece 48 is in a so-called cantilever state in which one end is fixed to the enlarged diameter portion 45 and the other end is a free end. The guide piece 48 is elastically deformed according to the flow velocity of the ink flow in the ink introduction path 42. The front end portions 49 of the guide pieces 48 are arranged with an interval 50 therebetween. The interval 50 maintains at least a distance through which ink can pass. That is, the interval 50 ensures an ink flow path.

  The guide piece 48 has the tip 49 in the filter 18 at a relatively low flow rate (during normal recording operation) of the ink flow in the ink introduction path 42, that is, at the flow rate of the ink flow when ejecting droplets from the nozzle openings 26. It is the 1st state spaced apart to the upstream rather than. The guide piece 48 is also in the first state when the ink in the ink introduction path 42 is staying (not flowing).

  FIG. 8 is a cross-sectional view of the ink introduction needle 19 during the cleaning operation. The guide piece 48 bends to the downstream side at a relatively high flow rate of the ink flow in the ink introduction path 42 (during the cleaning operation), that is, the flow rate of the ink flow when the liquid droplets are forcibly discharged from the nozzle opening 26. A second state is obtained in which the tip 49 is brought close to the filter 18.

  Since the guide piece 48 in the second state restricts the ink flow from the tip 49 of the bent guide piece 48 to the inner peripheral surface 47 side (the back side of the guide piece 48), the ink flow is controlled to the outer peripheral side of the filter 18. Rather than guiding to the center side of the filter 18. That is, the guide piece 48 in the second state regulates the flow direction of the ink flow. The guide piece 48 in the second state throttles (chokes) the flow path, and allows the ink flow to pass through the center side of the filter 18 at a high speed.

Next, a state in which bubbles have entered the ink introduction needle 19 provided with the guide piece 48 will be described.
9A and 9B are schematic diagrams for explaining the movement of bubbles in the ink introduction needle 19. FIG. 9A is a cross-sectional view of the ink introduction needle 19 during a normal recording operation, and FIG. 9B is an ink introduction needle 19 during a cleaning operation. FIG. First, as shown in FIG. 9A, when air bubbles stay in the straight portion 44 of the ink introduction needle 19, a cleaning operation is performed, and as shown in FIG. As the guide piece 48 is bent toward the filter 18, the bubbles move toward the filter 18. The guide piece 48 restricts the ink and air bubbles from flowing around the back side of the front end portion 49 (the flow direction of the ink flow), so that the front end portion 49 of the guide piece 48 is in a state of holding the air bubbles. The filter 18 is positioned on the center side and pressed toward the filter 18. Therefore, bubbles pass along with the ink from the center side of the filter 18.

  As described above, in the recording head 3, the guide piece 48 extends from the upstream end 51 of the enlarged diameter portion 45 toward the radial center O of the ink introduction path 42 so as to have flexibility, and the distal end portion. The ink introduction path is divided into a first state in which 49 is spaced upstream of the filter 18 and a second state in which the distal end portion 49 is brought close to the filter 18 and the flow direction of the ink flow is regulated by bending downstream. Therefore, when the flow rate of the ink flow in the ink introduction path 42 is low, the guide piece 48 is in the first state and the filter 18 and the guide piece 48 are separated from each other. It is possible to temporarily capture bubbles that have grown excessively while securing a flow path in the space, thereby preventing the bubbles from blocking the flow path. When the flow rate of the ink flow in the ink introduction path 42 is high, the guide piece 48 is bent to be in the second state, and the ink flows from the tip 49 to the inner peripheral surface 47 side (the back side of the guide piece 48). Therefore, the ink is guided to the center side of the filter 18 rather than the outer peripheral edge side of the filter 18 and passes through the center side of the filter 18 at a high speed. Can be passed. Therefore, it is possible to reduce the number of executions of the cleaning operation and suppress consumption of liquid ink.

  Further, since each guide piece 48 is bent downstream, the flow direction of the ink flow can be concentrated and guided to the center side of the filter 18. In addition, when the flow rate of the ink flow in the ink introduction path 21 is slow (normal printing), even if bubbles grow to the extent that the bending of the guide piece 48 is prevented, the interval 50 between the guide pieces 48 is used as a flow path. Can be secured. Therefore, it is possible to prevent problems such as insufficient supply of ink due to air bubbles blocking the flow path.

  Further, since the guide piece 48 is disposed at the upstream end portion 51 of the enlarged diameter portion 45, it flows into the enlarged diameter portion 45 when the flow rate of the ink flow in the ink introduction path 42 is fast (cleaning operation). It is possible to suppress the ink flow to flow down toward the inner peripheral surface 47. Therefore, since the fluid passes through the center side of the filter 18 at high speed, the bubbles can be efficiently passed through the filter together with the liquid. In addition, since the bubbles can be retained in the enlarged diameter portion that is larger in diameter than the liquid inflow portion, it is possible to prevent the flow path from being blocked by the bubbles.

Next, a second embodiment of the ink introduction needle 19 provided with the guide piece 48 will be described.
10A and 10B are schematic diagrams for explaining the movement of bubbles in the ink introduction needle 19 in this embodiment. FIG. 10A is a cross-sectional view of the ink introduction needle 19 during a normal recording operation, and FIG. 4 is a cross-sectional view of the ink introduction needle 19 of FIG. The guide piece 48 of the ink introduction needle 19 in the present embodiment is characterized in that, when the guide piece 48 is bent to be in the second state, the tip end portion 49 comes into contact with a position closer to the center than the outer peripheral edge on the upstream surface of the filter 18. . That is, the guide piece 48 intensively guides the ink flow from the upstream side to a part of the upstream surface of the filter 18.

  In the second embodiment, as shown in FIG. 10B, the cleaning operation is performed from the state where the bubbles stay in the straight portion 44 of the ink introduction needle 19 as shown in FIG. The guide piece 48 is bent toward the filter 18 by the downward flow of the ink flow, and the bubbles move toward the filter 18. The guide piece 48 prevents the tip 49 from coming into contact with a position closer to the center than the outer peripheral edge on the upstream surface of the filter 18 and prevents ink and bubbles from flowing around the back of the tip 49 (the ink flow direction). To do. For this reason, it will be in the state where the front-end | tip part 49 of the guide piece 48 hold | maintains a bubble. In this way, the bubbles are positioned on the center side of the filter 18 and pressed toward the filter 18. Therefore, bubbles pass along with the ink from the center side of the filter 18.

  As described above, in the recording head 3, when the guide piece 48 is in the second state, the distal end portion 49 contacts the position on the center side of the outer peripheral edge on the upstream surface of the filter 18. The ink flow flowing along the surface on the diameter center side (front side of the guide piece 48) of the ink introduction path 42 is prevented from flowing into the space between the back side surface of the bent guide piece 48 and the inner peripheral surface 47. In addition, by narrowing the flow path width on the upstream surface of the filter 18, it is possible to guide the ink flow intensively to the center side of the filter 18 and allow the ink flow to pass from a part of the upstream surface of the filter 18 at a high speed. .

Next, a third embodiment of the ink introduction needle 19 provided with the guide piece 48 will be described.
FIG. 11 is a schematic diagram for explaining the movement of bubbles in the ink introduction needle 19 in the present embodiment. FIG. 11A is a cross-sectional view of the ink introduction needle 19 during a normal recording operation, and FIG. 4 is a cross-sectional view of the ink introduction needle 19 of FIG. The ink introduction needle 19 in this embodiment is characterized in that a cylindrical guide auxiliary member 53 is disposed on the upstream surface of the filter 18. That is, the guide assisting member 53 is formed in a cylindrical shape and has a guide channel 54 through which ink can pass on the central axis O. The inner diameter of the guide channel 54 is set smaller than the diameter of the filter 18. When the guide piece 48 is bent to be in the second state, the guide piece 48 is bent toward the guide channel 54 with the distal end portion 49 directed to guide the ink flow from the upstream into the guide channel 54.

  In the third embodiment, as shown in FIG. 11A, the cleaning operation is performed from the state where bubbles stay in the straight portion 44 of the ink introduction needle 19 as shown in FIG. The tip 49 of the guide piece 48 bends into the guide channel 54 due to the downward flow of the ink flow, and the bubbles move toward the filter 18. And since the guide auxiliary member 53 becomes a wall and narrows the flow path width on the upstream surface of the filter 18, the guide piece 48 and the guide auxiliary member 53 regulate the flow direction of the ink flow. For this reason, it will be in the state where the front-end | tip part 49 of the guide piece 48 hold | maintains a bubble. In this way, the bubbles are positioned on the center side of the filter 18 and pressed toward the filter 18. Therefore, bubbles pass along with the ink from the center side of the filter 18.

  According to the above configuration, the guide auxiliary member 53 having the guide flow path 54 through which the fluid can pass is disposed on the upstream surface of the filter 18, so that the guide auxiliary member 53 serves as a wall and the upstream surface of the filter 18. Narrow the flow path width. Since the guide auxiliary member 53 regulates the flow direction of the ink flow together with the guide piece 48, the ink flow is intensively guided to a part of the filter 18, and the bubbles can be efficiently passed through the filter 18 together with the liquid. it can. Further, the ink flow that passes through the filter 18 is divided into an ink flow that has passed through the guide flow path 54 and an ink flow that has passed between the guide auxiliary member 53 and the inner peripheral surface 47, and allows ink to pass. Therefore, it is possible to secure both the flow path for the purpose and the flow path for temporarily capturing the bubbles. Therefore, problems such as insufficient ink supply due to the filter 18 being blocked by bubbles can be prevented.

  In addition, regarding each guide piece 48 in the present embodiment, the number of guide pieces 48 may be increased as shown in FIG. Moreover, as shown in FIG.12 (b), it is good also as a base-shaped shape. When the number and shape of the guide pieces 48 are changed in this way, the interval 50 between the guide pieces 58 is increased, and air bubbles can be easily guided.

  Moreover, you may arrange | position only one guide piece. In this case, the guide piece 48 is disposed with a space 50 between the guide piece 48 and the inner peripheral surface 47. That is, the interval 50 functions as an interval through which ink can pass. As a result, when the flow rate of the fluid in the ink introduction path 42 is low (normal printing), even if bubbles grow to the extent that the bending of the guide piece 48 in the first state is prevented, the guide piece 48 Since the space 50 between the inner peripheral surface 47 and the inner peripheral surface 47 can be secured as a flow path, problems such as insufficient supply of ink due to air bubbles blocking the flow path can be prevented.

By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.
In each said embodiment, although the example which provided the guide piece 48 only in the upstream edge part 51 of the enlarged diameter part 45 was shown, it does not restrict to this, For example, each guide piece 48 of the enlarged diameter part 45 is shown. It may extend from anywhere on the inner peripheral surface 47, or may extend from the inner peripheral surface of the straight portion 44 toward the diameter center O side of the ink introduction path 42. Also in this configuration, the guide piece 48 has a first state in which the tip 49 is separated upstream of the filter 18, and the guide piece 48 is bent downstream to bring the tip 49 close to the filter 18 so that the flow direction of the ink flow is reduced. The second state to be regulated can be converted according to the flow rate of the ink flow in the ink introduction path 42, and the same effects as those in the above embodiments can be obtained.

  In the above, the printer 1 which is a kind of liquid ejecting apparatus has been described as an example, but the present invention can also be applied to other liquid ejecting apparatuses. For example, a display manufacturing apparatus that manufactures color filters such as liquid crystal displays, an electrode manufacturing apparatus that forms electrodes such as organic EL (Electro Luminescence) displays and FEDs (surface-emitting displays), and chips that manufacture biochips (biochemical elements) The present invention can also be applied to a manufacturing apparatus or the like.

FIG. 2 is a perspective view illustrating a configuration of a printer. FIG. 2 is an exploded perspective view illustrating a configuration of a recording head. FIG. 3 is a plan view illustrating a configuration of a recording head. 2 is a cross-sectional view illustrating an internal structure of a recording head. FIG. 2 is a partial cross-sectional view illustrating an internal structure of a recording head. FIG. It is sectional drawing of the needle longitudinal direction of an ink introduction needle. It is the VII-VII sectional view taken on the line in FIG. FIG. 6 is a cross-sectional view of an ink introduction needle during a cleaning operation. 4A and 4B are schematic diagrams for explaining the movement of bubbles in the ink introduction needle, where FIG. 5A is a cross-sectional view of the ink introduction needle during a normal recording operation, and FIG. 5B is a cross-sectional view of the ink introduction needle during a cleaning operation. FIG. 6 is a schematic diagram for explaining the movement of bubbles in an ink introduction needle in the second embodiment, where (a) is a cross-sectional view of the ink introduction needle during a normal recording operation, and (b) is an ink introduction needle during a cleaning operation. FIG. FIG. 10 is a schematic diagram for explaining the movement of bubbles in an ink introduction needle in a third embodiment, where (a) is a cross-sectional view of the ink introduction needle during a normal recording operation, and (b) is an ink introduction needle during a cleaning operation. FIG. It is sectional drawing explaining the modification of a guide piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording medium, 3 ... Recording head, 4 ... Carriage, 5 ... Carriage moving mechanism, 6 ... Platen roller, 7 ... Ink cartridge, 8 ... Timing belt, 9 ... Pulse motor, 10 ... Guide rod, 11 DESCRIPTION OF SYMBOLS ... Wiping mechanism, 12 ... Capping mechanism, 13 ... Pump unit, 15 ... Base, 16 ... Head case, 17 ... Flow path unit, 18 ... Filter, 19 ... Ink introduction needle, 20 ... Circuit board, 21 ... Sheet member, 22 ... vibrator unit, 23 ... elastic plate, 24 ... flow path forming substrate, 25 ... nozzle plate, 26 ... nozzle opening, 27 ... head cover, 29 ... piezoelectric vibrator, 30 ... piezoelectric vibrator group, 31 ... fixing plate, 32 ... Storage empty part, 33 ... Common ink chamber, 34 ... Ink supply port, 35 ... Pressure chamber, 36 ... Island part, 37 ... Ink communication path, 42 ... Ink introduction path 43: Pointed portion, 44: Straight portion, 45: Expanded diameter portion, 46: Ink introduction hole, 47 ... Inner peripheral surface, 48 ... Guide piece, 49 ... Tip portion, 50 ... Distance, 51 ... Upstream end portion, 53 ... Guide auxiliary member, 54 ... Guide flow path, O ... Center of diameter

Claims (10)

A liquid ejecting head that introduces liquid into a pressure chamber through a liquid inflow portion and discharges liquid droplets from a nozzle opening by pressure fluctuation,
On the downstream side of the liquid inflow portion, an enlarged diameter portion that is larger than the inner diameter of the liquid inflow portion is provided,
Place a filter in the enlarged diameter part,
Extending a flexible guide piece from the inner peripheral surface of the liquid inflow portion upstream of the filter toward the diameter center side of the liquid inflow portion,
The guide piece has a first state in which a tip portion is spaced upstream of the filter, and a second state in which the tip portion is bent downstream and the tip portion is brought close to the filter to regulate a fluid flow direction. Further, the liquid ejecting head is converted according to the flow velocity of the fluid in the liquid inflow portion.   The guide piece is converted to the first state in the flow velocity of the fluid when the droplet is ejected from the nozzle opening, and the flow rate in the fluid when the fluid in the liquid inflow portion is forcibly discharged from the nozzle opening. The liquid jet head according to claim 1, wherein the liquid jet head is converted to a second state.   3. The liquid ejecting head according to claim 1, wherein the guide piece forms at least a gap through which the liquid can pass between the guide piece and the inner peripheral surface of the liquid inflow portion in the first state. A plurality of the guide pieces;
4. The liquid jet head according to claim 1, wherein the guide pieces are disposed in a state in which at least a gap through which the liquid can pass is formed in the first state. 5.   5. The liquid ejecting head according to claim 1, wherein the guide piece is disposed at an upstream end portion of the enlarged diameter portion.   6. The liquid ejecting head according to claim 1, wherein the guide piece makes a tip end thereof contact an upstream surface of the filter in the second state. 7.   The guide piece is in contact with a position closer to the center than the outer peripheral edge of the upstream surface of the filter, and guides fluid from the upstream side intensively to the upstream surface of the filter. The liquid jet head described in 1.   6. The liquid jet head according to claim 1, wherein a guide auxiliary member having a guide flow path through which a fluid can pass is disposed on an upstream surface of the filter.   The liquid ejecting head according to claim 8, wherein an inner diameter of the guide channel is set smaller than a diameter of the filter.   10. The guide piece according to claim 8 or 9, wherein in the second state, the guide piece is bent toward a guide channel of the guide auxiliary member with a tip portion directed to guide a fluid from an upstream side to the guide channel. The liquid jet head described in 1.

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