JP2006069168A - Liquid injection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid injection apparatus which more efficiently removes bubbles in a liquid flow path. <P>SOLUTION: An ink guiding needle 19 is constituted of: a tapered tip 43; a cylindrical straight section 44 continuously formed on a downstream side of the tip 43; and an enlarged diameter section 45 continuously formed on a downstream side of the straight section 44 and having an inner diameter enlarged larger than the inner diameter of the straight section. The enlarged diameter section 45 has: a plurality of ribs 47 protruded from an inner peripheral surface toward a diameter center; and air bubble chambers 48 formed, partitioned by both ribs adjacent to each other in the peripheral direction. Each rib is extended from an upstream end side of the enlarged diameter section through to a downstream end side, and its tip is protruded in front of a filter 18 in a vicinity of a virtual inner periphery surface C formed by extending the inner peripheral surface of the straight section to the downstream side to move bubbles in an upper section of the filter into a bubble chamber with a flow-down force of ink passing inside the ink guiding needle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet recording apparatus, and in particular, introduces a liquid stored in a liquid storing member to a liquid ejecting head side through a liquid introducing needle, and drops liquid from the liquid ejecting head. The present invention relates to a liquid ejecting apparatus that discharges as

  Examples of a liquid ejecting apparatus having a liquid ejecting head capable of ejecting liquid in the form of droplets include an image recording apparatus that ejects ink droplets to record an image on recording paper, and ejects a liquid electrode material onto a substrate. An electrode forming apparatus for forming an electrode and a biochip manufacturing apparatus for manufacturing a biochip by discharging a biological sample have been proposed.

  As this type of liquid ejecting apparatus, an apparatus using a cartridge-type liquid storage member that is easy to be put on distribution and easy to handle has been proposed. For example, ink jet printers that are a type of image recording apparatus are widely used that use ink cartridges containing liquid ink. In this configuration, by mounting the cartridge in the cartridge mounting portion and inserting the liquid introduction needle into the cartridge, the liquid in the cartridge is brought to the liquid ejecting head side through the liquid introduction hole formed in the distal end side of the liquid introduction needle. It has been introduced. For example, in the above printer, the ink enclosed in the ink cartridge is introduced to the recording head side by mounting the ink cartridge in the cartridge holder provided in the carriage.

  In the configuration using the cartridge, it is desirable that the liquid flow path from the liquid introduction needle to the liquid ejecting head is filled with the used liquid, but the liquid storage space in the unused cartridge is adjusted to a deaerated (negative pressure) state. Therefore, when the liquid introduction needle is inserted into the cartridge and the valve in the cartridge is opened, air enters the boundary portion between the cartridge and the liquid introduction needle. When filling the liquid into the liquid ejecting head, the air may be introduced into the liquid introduction needle together with the liquid as bubbles. If the bubbles move on the liquid flow at the time of use and move to the liquid jet head side, there is a possibility that a problem occurs in the discharge of the liquid. For example, a bubble may come into contact with a foreign matter filtering filter disposed at the downstream end of the liquid introduction needle, and the surface of the filter may remain covered with the bubble. In this case, since the passage of the liquid filter is hindered by the bubbles covering the filter, the supply amount of the liquid is insufficient, and a so-called multi-nozzle missing state in which the liquid is not discharged from many nozzle openings occurs. Further, when the bubbles pass through the filter, the bubbles are discharged from the nozzle opening to the outside of the head, so that a so-called dot missing state in which no liquid droplet is discharged from the nozzle opening occurs.

  In order to prevent such problems caused by bubbles, a plurality of convex pieces are provided upstream of the filter in the liquid introduction needle, and the convex pieces are configured to capture the bubbles at a position away from the filter. Proposals have been made in which bubbles are prevented from flowing into the recording head through the filter, and a groove formed between the convex pieces is secured as a passage through which ink can pass (for example, Patent Document 1). reference).

Japanese Patent No. 3427878 (page 3, FIG. 4)

  By the way, in this type of ink jet printer, a so-called cleaning operation is performed in which air bubbles in the liquid introduction needle are forcibly sucked and discharged from the nozzle opening together with 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 liquid 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, in the case of a configuration in which bubbles are captured at a position away from the filter as in the invention of Patent Document 1, the bubbles are difficult to pass through the filter. It is necessary to set a higher suction force and suction time in the cleaning operation. For this reason, there has been a problem that a large amount of liquid in the cartridge is consumed by this cleaning operation.

  Further, as shown in FIG. 4 (D) of the above-mentioned Patent Document 1, even when the trapped bubble grows greatly in the internal space of the base (expanded diameter portion) of the supply needle over time, the bubble is filtered. It is easy to spread in a relatively large space above, and the contact area of bubbles with respect to the filter is small. For this reason, it is difficult to efficiently remove bubbles in the cleaning operation.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting apparatus that can more efficiently remove bubbles in a liquid flow path.

In order to achieve the above object, the liquid ejecting apparatus of the present invention includes a liquid introduction needle that introduces the liquid in the liquid storage member into the liquid flow path from the liquid introduction hole,
A filter that is disposed on the root side of the liquid introduction needle and that filters the liquid in the liquid channel;
A liquid ejecting head capable of introducing the liquid filtered by the filter into the pressure chamber and discharging the liquid in the pressure chamber as droplets from the nozzle opening by the operation of the pressure generating means;
The liquid introduction needle is
A pointed end formed in a tapered shape;
A cylindrical straight portion formed continuously on the downstream side of the tip portion;
The continuous portion is formed on the downstream side of the straight portion, and the inner diameter of the straight portion is larger than the inner diameter of the straight portion.
The enlarged diameter portion has a plurality of ribs projecting from the inner peripheral surface toward the center of the diameter, and a bubble chamber defined by both ribs adjacent in the circumferential direction,
Each rib extends from the upstream end side to the downstream end side of the enlarged diameter portion, and the tip thereof is in the vicinity of the virtual inner peripheral surface extending the inner peripheral surface of the straight portion to the downstream side and the filter. Protruding to the front,
According to the present invention, the bubble above the filter is moved into the bubble chamber by the downward flow of ink passing through the liquid introduction needle.

  According to the above configuration, since the bubbles are moved into the bubble chamber partitioned by the plurality of ribs by the downward flow of the ink passing through the liquid introduction needle, it is narrower than the entire internal space of the enlarged diameter portion. The air bubbles pushed into the air bubble chamber are easily brought into close contact with the filter due to the pressure of the ink from the upstream side to the filter side, and the contact area of the air bubbles to the filter can be increased. Therefore, in the cleaning operation, bubbles can pass through the filter even at a relatively low flow rate, and the bubble discharge efficiency can be improved. Accordingly, the suction force during the cleaning operation can be kept low and the suction time can be shortened. As a result, the ink consumption amount during the cleaning operation can be reduced.

  In the above configuration, it is desirable that the ribs are arranged at equal intervals in the circumferential direction on the inner peripheral surface of the enlarged diameter portion.

  Moreover, in each said structure, it is also possible to employ | adopt the structure which each rib extends over the downstream end side of the said enlarged diameter part from the upstream end side of the said straight part.

  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. The following description will be given by taking an ink jet recording apparatus as a typical liquid ejecting apparatus as an example.

  First, a schematic configuration of an ink jet recording apparatus (hereinafter referred to as a printer) will be described with reference to FIG. The printer 1 is an apparatus for recording 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 performs main scanning on an ink jet recording head 3 that discharges ink (corresponding to a kind of liquid ejecting head in the present invention, hereinafter referred to as “recording head”), a carriage 4 to which the recording head 3 is attached, and a carriage 4. A carriage moving mechanism 5 for moving the recording medium 2 in the direction, a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction, and the like are provided. Here, the ink is a kind of liquid of the present invention and is stored in the ink cartridge 7 (a kind of liquid storage member in the present invention). 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. Accordingly, 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 (width direction of the recording paper 2).

  A wiping mechanism 11 for wiping the nozzle forming surface (nozzle plate 25 / see FIG. 2) of the recording head 3 mounted on the carriage 4, for example, is disposed at a home position that is a non-recording area of the printer 1. Yes. The wiping mechanism 11 has, for example, a wiper blade 11 ′. The wiper blade 11 'is composed of an elastic member such as rubber or elastomer. The wiping mechanism 11 positions the wiper blade 11 ′ so that the tip of the wiper blade 11 ′ intersects the movement locus of the nozzle forming surface of the recording head 3 during wiping. As the recording head 3 passes, the tip of the wiper blade 11 ′ slides on the nozzle forming surface, and the nozzle forming surface is wiped off.

  A capping mechanism 12 is disposed adjacent to the wiping mechanism 11 at or near the home position. The capping mechanism 12 has a tray-like cap member 12 ′ that can come into contact with the nozzle forming surface of the recording head 3. In this capping mechanism 12, the space in the cap member 12 ′ functions as a sealing void, and the nozzle opening 26 (see FIG. 2) of the recording head 3 faces the nozzle forming surface in the sealing void. It is configured to be in close contact. 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. It is adapted to be discharged into the 12 'sealing 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 has a cartridge base 15 (hereinafter referred to as “base”). The base 15 is molded from, for example, a synthetic resin, and as shown in FIG. 3, a plurality of compartments 15 ′ (liquid storage member mounting portions) are provided on the upper surface thereof. An ink introduction needle 19 (corresponding to a liquid introduction needle in the present invention) is attached to each compartment 15 ′ with a filter 18 interposed. The ink cartridge 7 is mounted in these compartments 15 '. 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 15 ′. The circuit board 20 includes, for example, a drive circuit for controlling the supply of drive signals to the piezoelectric vibrator 30 ′ (see FIG. 5), a connector for connection to the printer main body, a through hole for supplying ink, and the like. It has. And this circuit board 20 is attached to the base 15 via the sheet | seat member 21 which functions as packing. The sheet member 21 has a through hole 21 ′ for supplying ink.

  The head case 16 is fixed to the base 15 and is a casing for housing the vibrator unit 22 having the piezoelectric vibrator 30 ′. 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. This flow path unit 17 is manufactured by joining and integrating with an 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. The head cover 27 is made of, for example, a metal thin plate member, and is attached to the distal end portion of the head case 16 so as to surround the peripheral edge portion from the outside of the nozzle plate 25. The head cover 27 protects the front end portions of the flow path unit 17 and the head case 16 and prevents peeling of each part of the flow path unit 17.

  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 30 'arranged in a comb shape. Each piezoelectric vibrator 30 ′ has a fixed end joined to the fixed plate 31, and a free end protruding outside the front end surface of the fixed plate 31. That is, each piezoelectric vibrator 30 ′ is mounted on the fixed plate 31 in a so-called cantilever state. The fixing plate 31 that supports each piezoelectric vibrator 30 'is made of stainless steel having a thickness of about 1 mm, for example. 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 the ink introduction path 42 (see FIG. 7) of the ink introduction needle 19 via the ink communication path 37 formed through the height direction of the head case 16, and the ink cartridge 7. This is a chamber into which the ink stored in 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 30 ′ is formed in 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 30 ′ is expanded and contracted in the longitudinal direction of the element, 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 functions as a kind of the liquid storage member of the present invention and is a member that stores ink 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. As shown in FIG. 6, a needle insertion opening 40 is provided on the bottom surface of each ink cartridge 7. The needle insertion port 40 is a portion into which the ink introduction needle 19 is inserted. At the time of shipment from the factory, the needle insertion port 40 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.

  7A and 7B are diagrams for explaining the configuration of the ink introduction needle 19 inserted into the ink cartridge 7. FIG. 7A is a sectional view in the longitudinal direction of the needle, and FIG. 7B is a sectional view taken along line AA in FIG. It is. The ink introduction needle 19 is a hollow needle having an internal space as an ink introduction path 42, and has a conical pointed portion 43 formed in a tapered shape and a cylinder formed continuously downstream from the pointed portion 43. The straight portion 44 is formed continuously with a downstream portion of the straight portion 44, and the inner diameter of the straight portion 44 is larger than the inner diameter of the straight portion 44. 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 diameter-expanded 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), and from its inner peripheral surface toward the diameter center. Plural plate-like ribs 47 are provided. The ribs 47 adjacent to each other in the circumferential direction form a plurality of compartments in the enlarged-diameter portion 45 in a substantially fan-shaped bubble chamber 48 in plan view. Details of the rib 47 and the bubble chamber 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. The ink introduction path 42 and the ink communication path 37 function as a liquid flow path in the present invention.

  When the ink cartridge 7 is mounted on the base 15, the ink introduction needle 19 is inserted into the needle insertion opening 40 of the ink cartridge 7, and the ink is introduced into the internal space (ink reservoir) of the ink cartridge 7 and the ink introduction needle 19. The path 42 communicates with the 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.

  By the way, as described above, since the internal space of the ink cartridge 7 is in a deaerated state, when the tip of the ink introduction needle 19 pushes up a valve (not shown) provided in the needle insertion port 40. Then, air enters the boundary portion 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 in a state where the cap member 12 ′ is in close contact with the nozzle forming surface, and the ink flow rate is several times that of normal ink ejection (recording operation). Is generated in the recording head 3, and the air bubbles in the ink introduction path 42 are discharged onto the ink flow by being put on the ink flow. 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 by this cleaning operation as much as possible, it is desirable to allow bubbles to pass through the filter 18 even at a relatively low flow rate.

  In order for bubbles in the ink introduction path 42 to easily pass through the filter 18 even at a relatively low flow rate, it is important that the contact area of the bubbles with the filter 18 is large. However, with this type of conventional ink introduction needle, from the viewpoint of preventing ejection failure due to bubbles entering the head, the bubbles in the ink introduction path easily pass through the filter during the normal recording operation. In order to prevent the air bubbles from moving to each other, bubbles are floated above the filter so as to be separated from the filter by providing a relatively wide space above the filter in the ink introduction path of the ink introduction needle. This makes it difficult to ensure a large contact area of bubbles with the filter in the cleaning operation. For this reason, in order to reliably remove bubbles, it is necessary to increase the flow rate of ink, which is a cause of wasteful consumption of ink.

In the printer 1, the above problem is solved by providing the plurality of ribs 47 and the bubble chambers 48 defined by these ribs 47 in the ink introduction needle 19. Hereinafter, this point will be described.
In the present embodiment, as shown in FIG. 7B, the four ribs 47 are formed integrally with the ink introduction needle 19 in a state where they are arranged at equal intervals in the circumferential direction of the inner peripheral surface of the enlarged diameter portion 45. Has been. A total of four bubble chambers 48 are partitioned and formed by the adjacent ribs 47 and the inner peripheral surface of the enlarged diameter portion 45 that continues both ribs 47.

Each rib 47 extends from the upstream end side (straight portion 44 side) to the downstream end side (filter 18 side) of the enlarged diameter portion 45, and at the tip (corner portion / P in FIG. 7A). The portion shown in FIG. 6 protrudes to the vicinity of the virtual inner peripheral surface (the portion indicated by C in FIG. 7B) obtained by extending the inner peripheral surface of the straight portion 44 to the downstream side and before the filter 18.
In other words, each rib 47 extends the edge in the needle radial direction to the virtual inner peripheral surface C, and extends the edge on the needle root side to the front of the filter 18. Accordingly, the ribs 47 are arranged radially about the virtual inner peripheral surface C. In the internal space of the enlarged diameter portion 45, a narrow space defined by the ribs 47 outside the virtual inner peripheral surface C is a bubble chamber 48.

  8A and 8B are schematic views for explaining the movement of ink and bubbles in the ink introduction needle 19. FIG. 8A is a cross-sectional view of the enlarged diameter portion 45 of the ink introduction needle 19, and FIG. It is A sectional view. In the ink introduction needle 19 in the present embodiment, since the edge in the needle diameter direction of the rib 47 projects to the virtual inner peripheral surface C, the ink passing through the enlarged diameter part 45 flows in the flow-down direction by the edge of each rib 47. Is regulated to a certain extent, and as indicated by the arrow in FIG. 8A, the ink introduction needle 19 flows down centrally, that is, in the virtual inner peripheral surface C. For this reason, the bubble B above the filter 18 is crushed in the center by the downward flow of ink from the upstream side, and moves to the outside in the needle diameter direction, that is, toward the bubble chamber 48. Finally, as shown in FIG. 8B, the bubbles B are pushed into the respective bubble chambers 48, and a hole is opened at the center thereof to secure a flow path through which ink can pass. . The air bubbles B pushed into the air bubble chamber 48 which is narrower than the entire internal space of the enlarged diameter portion 45 are likely to be in close contact with the filter 18 because the ink is pressed from the upstream side to the filter 18 side. It becomes a state. Thereby, the contact area with respect to the filter of the bubble B can be enlarged.

As described above, the ink introduction needle 19 is provided with the plurality of ribs 47 and the bubble chambers 48 defined by the ribs 47, and by pushing the bubbles into the bubble chamber 48 by the downward flow of ink, Since the contact area with the filter is increased, the bubbles can pass through the filter 18 even at a relatively low flow rate, and the bubble discharge efficiency in the cleaning operation can be improved. Therefore, with respect to the above suction conditions, the suction force can be kept low and the suction time can be shortened. As a result, the amount of ink consumed in the cleaning operation can be reduced.
Further, since the discharge efficiency is high, more bubbles can be removed by one cleaning operation, and the allowed time until the next cleaning operation is executed can be extended. Therefore, it is possible to contribute to further reduction of ink consumption.

Next, a second embodiment of the ink introduction needle 19 will be described.
FIG. 9 is a diagram showing the configuration of the ink introduction needle 19 in the present embodiment. The ink introduction needle 19 in this embodiment is characterized by having an eccentric structure. That is, the ink introduction needle 19 is configured such that the straight portion 44 is offset with respect to the enlarged diameter portion 45. Further, as shown in FIG. 9B, the ribs 47 are arranged in a cross shape with the virtual inner peripheral surface C as the center with the phases being different by 90 degrees in the circumferential direction of the virtual inner peripheral surface C. .

  In the example of FIG. 9, the diameter center of the straight portion 44 is to the right with respect to the diameter center at the bottom of the enlarged diameter portion 45, so the virtual inner peripheral surface C is also to the right accordingly. Therefore, each rib 47 of the ink introduction needle 19 in the present embodiment has a different protruding length depending on the bias of the virtual inner peripheral surface C as shown in FIG. 9B. Specifically, the rib 47 located on the right side in FIG. 9 is shorter and the rib 47 located on the left side is longer. Therefore, the size of the bubble chamber 48 also differs depending on the overhanging length of the rib 47 that partitions the bubble chamber 48. That is, the bubble chamber 48 located on the left side in FIG. 9 is larger than the bubble chamber 48 located on the right side.

  It was confirmed that the same effect as that of the above embodiment was obtained by the ink introduction needle 19 in the present embodiment. That is, the bubbles on the upper side of the filter 18 are pushed into the bubble chambers 48 by the downward flow of the ink that intensively flows down the virtual inner peripheral surface C, and a large contact area of the bubbles in the bubble chambers 48 with the filter is ensured. be able to. Therefore, it is possible to improve the bubble discharge efficiency in the cleaning operation, and as a result, it is possible to reduce the ink consumption in the cleaning operation.

  In addition, regarding each rib 47 in this embodiment, as shown in FIG.9 (c), it is equidistant in the circumferential direction of the inner peripheral surface of the enlarged diameter part 45, and equidistant in the circumferential direction of the virtual inner peripheral surface C. You may arrange so that it may become. Further, the ribs 47 may be arranged so that the volumes of the bubble chambers 48 are equal. Thus, if the volume of each bubble chamber 48 is made as uniform as possible, even if the ink introduction needle 19 has an eccentric structure, the bubbles can be uniformly accommodated in each bubble chamber 48. Thereby, a sufficient contact area of bubbles with respect to the filter 18 can be secured, and the bubble discharge effect in the cleaning operation can be enhanced.

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 of the above embodiments, the example in which the ribs 47 are provided only in the diameter-expanded portion 45 has been shown. However, the present invention is not limited to this, and for example, as shown in FIG. You may make it provide over the downstream end side of the enlarged diameter part 45 from the side. Also in this configuration, by projecting the tip (corner portion: P in FIG. 10) of the rib 47 to the vicinity of the virtual inner peripheral surface obtained by extending the inner peripheral surface of the straight portion 44 to the downstream side and before the filter 18, A bubble chamber can be defined in the ink introduction needle 19, and the same effect as 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 a perspective view explaining the structure of an ink cartridge. It is sectional drawing explaining the structure of an ink introduction needle | hook, (a) is sectional drawing of a needle | hook longitudinal direction, (b) is the sectional view on the AA line in (a). It is a schematic diagram explaining the movement of ink and bubbles in the ink introduction needle, (a) is a cross-sectional view in the vicinity of the filter of the ink introduction needle, (b) is a cross-sectional view taken along line AA in (a). It is sectional drawing explaining the structure of the ink introduction needle | hook in 2nd Embodiment, (a) is sectional drawing of a needle | hook longitudinal direction, (b) is the sectional view on the AA line in (a). It is sectional drawing explaining the modification of an ink introduction needle | hook.

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, 30 ... piezoelectric vibrator group, 31 ... fixed plate, 32 ... storage empty part, 33 ... Common ink chamber, 34 ... Ink supply port, 35 ... Pressure chamber, 36 ... Island part, 37 ... Ink communication path, 40 ... Needle insertion port, 42 ... Ink introduction path, 3 ... tip, 44 ... straight portion 45 ... enlarged diameter section, 46 ... ink introducing hole, 47 ... rib, 48 ... bubble chamber

Claims (3)

A liquid introduction needle for introducing the liquid in the liquid storage member into the liquid channel from the liquid introduction hole;
A filter that is disposed on the root side of the liquid introduction needle and that filters the liquid in the liquid channel;
A liquid ejecting head capable of introducing the liquid filtered by the filter into the pressure chamber and discharging the liquid in the pressure chamber as droplets from the nozzle opening by the operation of the pressure generating means;
The liquid introduction needle is
A pointed end formed in a tapered shape;
A cylindrical straight portion formed continuously on the downstream side of the tip portion;
The continuous portion is formed on the downstream side of the straight portion, and the inner diameter of the straight portion is larger than the inner diameter of the straight portion.
The enlarged diameter portion has a plurality of ribs projecting from the inner peripheral surface toward the center of the diameter, and a bubble chamber defined by both ribs adjacent in the circumferential direction,
Each rib extends from the upstream end side to the downstream end side of the enlarged diameter portion, and the tip thereof is in the vicinity of the virtual inner peripheral surface extending the inner peripheral surface of the straight portion to the downstream side and the filter. Protruding to the front,
2. A liquid ejecting apparatus according to claim 1, wherein a bubble above the filter is moved into the bubble chamber by a downward flow of ink passing through the liquid introduction needle.   2. The liquid ejecting apparatus according to claim 1, wherein the ribs are arranged at equal intervals in the circumferential direction on the inner peripheral surface of the enlarged diameter portion. The liquid ejecting apparatus according to claim 1, wherein each rib extends from an upstream end side of the straight portion to a downstream end side of the enlarged diameter portion.

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