JP2011167942A - Liquid ejection head, liquid ejection head unit and liquid ejection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head, a liquid ejection head unit and a liquid ejection apparatus which can improve printing quality by suppressing hitting against an ejection target medium of small liquid droplets and suppressing liquid faulty ejection caused by small liquid droplets. <P>SOLUTION: The liquid ejection head is equipped with: a head body 10 which has nozzle openings 11 for ejecting liquids; a cover 20 which is prepared projecting in an ejection direction of the liquid at the periphery of a liquid ejection surface 12 where the nozzle openings 11 are opened; a rectifying plate 30 which is set at a position separated from the liquid ejection surface 12 in the cover 20, and has openings 31 formed in a region opposed to the nozzle openings 11; and an air flow generating means 40 which generates an air flow along a surface direction of the liquid ejection surface 12 between the rectifying plate 30 and the liquid ejection surface 12. The rectifying plate 30 is set to be able to move in at least one direction of the surface direction of the liquid ejection surface or in a direction to tilt to the surface direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head that ejects liquid from a nozzle opening, a liquid ejecting head unit, and a liquid ejecting apparatus.

  A liquid ejecting apparatus typified by an ink jet recording apparatus such as an ink jet recording head or a plotter is a liquid ejecting capable of ejecting a liquid such as ink stored in a liquid storing means such as a cartridge or a tank as a droplet (ink droplet). A head (hereinafter also referred to as a recording head).

  The liquid ejecting apparatus includes a serial type liquid ejecting apparatus that performs printing while moving the liquid ejecting head in the scanning direction with respect to an ejected medium such as a recording sheet such as paper, and a nozzle across the width of the recording medium. A line-type liquid ejecting apparatus that performs printing simply by fixing a liquid ejecting head provided with an opening and transporting a recording medium has been put into practical use (for example, see Patent Document 1).

  However, in any of the serial type and line type liquid ejecting apparatuses, since the ejection target medium and the liquid ejecting head are relatively moved, an air flow is generated by this relative movement, and ink is ejected from the nozzle openings. When this occurs, small droplets (called mist or satellite droplets) separated from the main droplets (main droplets) are generated, and the small droplets are separated from the main droplets of the ejected medium by the flow of airflow. The print quality deteriorates due to adhesion to the ink. Further, the small droplets adhere to the liquid meniscus at the nozzle opening and destroy the meniscus, and the droplet cannot be normally discharged from the nozzle opening.

  In order to solve such a problem, a hood that covers from the nozzle opening to the vicinity of the ejected medium is provided on the liquid ejecting surface side of the recording head that ejects ink, and the relative movement between the ejected medium and the recording head is provided. A drawing head device has been proposed in which small droplets are prevented from landing at positions different from the main droplets by the generated airflow (see, for example, Patent Document 2).

  On the other hand, in the above-described liquid ejecting apparatus, there is a risk that ejection failure may occur due to ink thickening in the nozzle or adhesion of dust near the nozzle opening due to long-term use. Then, a flushing operation for recovering or maintaining the ejection characteristics of the liquid ejection head is performed by discharging thickened ink, dust, and the like. As a liquid ejecting apparatus that performs such a flushing operation, a belt-like opening formed corresponding to the nozzle row and a fluid receiving portion that corresponds to the nozzle row and is provided on the side in the width direction of the opening are provided. The thing provided with the flushing member which performs is proposed (for example, refer patent document 3).

Japanese Patent Laid-Open No. 5-16370 Japanese Patent Laid-Open No. 2000-62166 JP 2009-279664 A

  However, as in Patent Document 2, when a hood is provided only on the recording head, turbulent air flow is generated by the hood, and small droplets land on a position different from the main droplet of the ejection target medium, and printing is performed. There is a problem that the quality deteriorates and the meniscus is destroyed.

  Such a problem becomes prominent particularly when high-speed printing is performed by increasing the relative moving speed of the recording head and the ejection target medium.

  In addition, the apparatus disclosed in Patent Document 3 has a problem of high cost because it is necessary to provide a flushing member specially.

  Further, the above-described problem exists not only in the ink jet recording head that ejects ink but also in a liquid ejecting head that ejects liquid other than ink.

  In this embodiment, in view of such circumstances, it is possible to improve the printing quality by suppressing the landing of the small liquid droplets on the ejection target medium and suppressing the liquid ejection failure due to the small liquid droplets. An object is to provide a liquid ejecting head, a liquid ejecting head unit, and a liquid ejecting apparatus that can perform a flushing operation at high speed without providing a member.

  An aspect of the present invention that solves the above-described problems includes a head body having a nozzle opening for ejecting liquid, a cover that protrudes in the liquid ejecting direction around a liquid ejecting surface on which the nozzle opening opens, A rectifying plate provided in the cover at a position away from the liquid ejection surface and having an opening in a region facing the nozzle opening, and the liquid ejection between the rectification plate and the liquid ejection surface An airflow generating means for generating an airflow along the surface direction of the surface, and the rectifying plate is movable in at least one direction of the liquid ejection surface or in a direction inclined with respect to the surface direction. The liquid ejecting head is provided.

  In such an embodiment, the main droplets of the droplets ejected from the nozzle openings do not move in the direction intersecting the ejection direction by the air current, but go straight and land on the ejected medium, and the small droplets separated from the main droplets By being moved by the air current, it is possible to suppress landing on the current plate and landing of small droplets on the ejection target medium or adhesion to the meniscus of the nozzle opening. In addition, by providing the cover, airflow due to relative movement between the ejection target medium and the liquid ejecting head, external airflow, and the like are shielded by the cover, and an airflow different from the airflow generated by the airflow generating means is generated in the vicinity of the liquid ejecting surface. Generation | occurrence | production can be suppressed and the landing position shift of a main droplet can be suppressed. Furthermore, by providing the rectifying plate so as to be movable, the rectifying plate can be used as a fluid receiving member during the flushing operation, and the flushing operation can be performed at high speed without providing a special member.

  Here, it is preferable that the current plate is movable together with the cover. According to this, attachment and movement of a baffle plate can be performed comparatively easily.

  Moreover, it is preferable that at least the surface of the current plate is formed of an adsorbent material. According to this, the fluid during the flushing operation can be received more reliably.

  Moreover, it is preferable to provide a moving means for positioning and moving the current plate. According to this, by providing the moving means integrally with the head main body, switching between the normal liquid ejecting operation and the flushing operation can be performed with high accuracy and reliability.

  It is preferable that a plurality of the head main bodies are provided, and the cover is provided continuously around the plurality of head main bodies. According to this, the number of parts can be reduced and the cost can be reduced.

  Moreover, it is preferable that the said airflow generation means generate | occur | produces the airflow of the gas which got moisture. According to this, it is possible to suppress the drying of the liquid in the vicinity of the nozzle opening from being promoted by the air flow generated by the air flow generating means, and to reduce ejection failures due to the drying / curing of the liquid.

According to another aspect of the invention, there is provided a liquid ejecting head unit including two or more liquid ejecting heads according to the above aspect.
In such an embodiment, a head unit having multiple nozzles can be easily formed.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head or the liquid ejecting head unit according to the above aspect.
In this aspect, it is possible to realize a liquid ejecting apparatus that can improve printing quality and perform high-speed printing.

3 is a perspective view of a recording head according to Embodiment 1. FIG. 2A and 2B are a bottom view and a main part sectional view of the recording head according to the first embodiment. FIG. 4 is a cross-sectional view of a main part illustrating the operation of the recording head according to the first embodiment. FIG. 4 is a cross-sectional view of a main part illustrating the operation of the recording head according to the first embodiment. 6 is a bottom view of the main part for explaining the operation of the recording head according to Embodiment 1. FIG. FIG. 3 is a bottom view of the head unit according to the first embodiment. 1 is a schematic perspective view of a recording apparatus according to Embodiment 1. FIG. 6 is a bottom view of a head unit according to Embodiment 2. FIG. It is a bottom view of a recording head showing a modification of a current plate concerning other embodiments.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is a perspective view illustrating an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention, and FIG. 2 is a bottom view and a main part sectional view of the ink jet recording head.

  As shown in FIG. 1, an ink jet recording head 1 (hereinafter also referred to as a recording head 1) that is an example of a liquid ejecting head of the present embodiment includes a head body 10 and a cover that covers a liquid ejecting surface 12 of the head body 10. 20, a current plate 30 fixed to the cover 20, and an airflow generation means 40.

  The head main body 10 is provided with a plurality of nozzle openings 11 that discharge ink as a liquid and open on one surface. The surface on which the nozzle opening 11 is opened is a liquid ejection surface 12 that ejects ink as a liquid.

  Further, the head body 10 is provided with a flow path 13 communicating with the nozzle opening 11 inside, and an ink droplet is generated from the nozzle opening 11 by causing a pressure change to the ink in the flow path 13 by pressure generation means (not shown). Is discharged. In addition, as a pressure generating means for generating a pressure change in the flow path 13, for example, a piezoelectric actuator using a piezoelectric element having a piezoelectric material exhibiting an electromechanical conversion function, or a heating element is disposed in the flow path 13. In the flow path 13, the ink droplets are ejected from the nozzle openings 11 by bubbles generated by the heat generated by the heating elements, or static electricity is generated between the diaphragm and the electrode, and the diaphragm is deformed by electrostatic force. A so-called electrostatic actuator that causes a change in pressure to eject ink droplets from the nozzle openings 11 can be used.

  A cover 20 is provided on the side surface of the head body 10 on the liquid ejection surface 12 side. The cover 20 surrounds the liquid ejecting surface 12 of the recording head 1 and is provided so as to protrude in the ink ejection direction. The cover 20 of the present embodiment is formed of a rectangular tube-shaped member whose opening is rectangular, and is integrated with the head body 10 by inserting and fixing the liquid ejection surface 12 side of the head body 10 into one opening. Has been. Such a cover 20 covers the flying area where ink is ejected opposite to the liquid ejecting surface 12 from the liquid ejecting surface 12 to the vicinity of the recording medium. Suppress.

  A rectifying plate 30 is fixed inside the cover 20. The rectifying plate 30 is composed of a plate-like member provided opposite to the liquid ejecting surface 12 and at a position away from the liquid ejecting surface 12.

  The rectifying plate 30 is provided with an opening 31 having a size that allows ink droplets (main droplets) ejected from the nozzle openings 11 to pass through a region facing each nozzle opening 11. Here, the opening 31 through which the main droplet can pass opposite to the nozzle opening 11 may be, for example, the opening 31 provided independently for each nozzle opening 11, or two or more nozzles The opening 31 provided corresponding to the nozzle opening group which consists of the opening 11 may be sufficient. That is, one opening 31 may be provided for each nozzle opening 11, or one opening 31 may be provided in common for the plurality of nozzle openings 11.

  Further, the rectifying plate 30 may be entirely closed except for the area other than the opening 31, and other openings may be provided in addition to the area facing the nozzle opening 11. As the rectifying plate 30 provided with other openings other than the region facing the nozzle opening 11, for example, the openings 31 are provided in a grid pattern by making resin, fiber, nonwoven fabric, paper, or the like into a lattice shape. A mesh member is mentioned. If the pitch (interval) of the openings 31 of the mesh member is an integral multiple of the pitch of the nozzle openings 11, the openings 31 can be opposed to all the nozzle openings 11. In addition, the size and pitch of the openings 31 of the mesh member may be provided so that one opening 31 faces each nozzle opening 11 as described above, and one opening 31 includes a plurality of openings 31. It may be provided so as to face the nozzle opening 11.

  In addition, it does not specifically limit as a material of the baffle plate 30, For example, a metal material, a resin material, a fiber, a nonwoven fabric, paper etc. can be used. However, by using a material having adsorptive properties, that is, water absorption, for example, as the current plate 30, when ink adheres to the current plate 30, in particular, the current plate 30 having ink adsorbing property during the flushing operation. Therefore, it is possible to prevent the ink adhering to and held securely and adhering to the current plate 30 from dropping and adhering to the ejection target medium at an unexpected timing.

  Such a rectifying plate 30 is arranged at a position away from the liquid ejection surface 12 by a predetermined distance as described above. Thereby, a space 32 for moving small droplets is defined between the current plate 30 and the liquid ejection surface 12.

  The rectifying plate 30 is preferably provided in the vicinity of the liquid ejecting surface 12 between the liquid ejecting surface 12 and the recording medium. This is because the main droplet ejected from the nozzle opening 11 may be landed at a position deviated from the nozzle opening 11 due to being largely affected by the deviation of the ejection direction and the air flow as it leaves the nozzle opening 11. This is because if the rectifying plate 30 is separated from the liquid ejection surface 12, the error increases and the main droplet may not pass through the opening 31 of the rectifying plate 30. Therefore, by providing the rectifying plate 30 in the vicinity of the liquid ejection surface 12, the main droplet discharged from the nozzle opening 11 can easily pass through the opening 31. In the present embodiment, the interval between the liquid ejection surface 12 and the rectifying plate 30 is set to about 1 mm.

  Further, the space 32 between the current plate 30 and the liquid ejection surface 12 is externally provided by a pair of communication holes 21 provided so as to face each other on the side surfaces of the cover 20 on both sides in the direction in which the nozzle openings 11 are arranged in parallel. Communicate.

  The airflow generation means 40 generates an airflow in the space 32 between the liquid ejection surface 12 and the rectifying plate 30 along the surface direction of the liquid ejection surface 12. In the present embodiment, the airflow generation means 40 including a blower is provided at a location where one communication hole 21 on the outer periphery of the cover 20 opens.

  As a result, gas is blown from the airflow generating means 40 into the cover 20 through the one communication hole 21, and the nozzle openings 11 are arranged in parallel in the space 32 between the liquid ejection surface 12 and the rectifying plate 30. An air flow is generated along the surface direction of the liquid ejection surface 12 and the cover 20 in the direction. The gas blown from the airflow generation means 40 is discharged from the other communication hole 21 to the outside of the cover 20, thereby suppressing the generation of turbulent airflow when the gas contacts the cover 20.

  In addition, the airflow generation means 40 is not limited to a blower, For example, a suction pump etc. may be sufficient.

  The airflow generated by the airflow generation means 40 will be described in detail later, but the main droplet of the ink droplet ejected from the nozzle opening 11 travels straight without being influenced by the airflow, and is a small droplet separated from the main droplet. Is the flow velocity that moves under the influence of airflow. By the way, the size (mass) of the main droplets and the size (mass) of the small droplets change due to the influence of the performance of the pressure generating means and the drive waveform that defines the weight and speed of the ejected ink droplets. Depending on these, it may be determined appropriately.

  Furthermore, in the present embodiment, the rectifying plate 30 is provided so as to be movable with respect to the cover 20 in a plane direction parallel to the liquid ejecting surface 12, that is, in the left-right direction in FIG. Specifically, the periphery of the current plate 30 is fixed to a frame body 25 that can move in the surface direction with respect to the cover 20, and the frame body 25 can be positioned and moved by the moving means 50.

  Although the details of the moving means 50 will be described later, the normal operation position where the nozzle opening 11 and the opening 31 of the rectifying plate 30 face each other and the frame portion 33 other than the nozzle opening 11 and the opening 31 of the rectifying plate 30 face each other. For example, an actuator, an electromagnet, a motor, or the like may be used.

  The ejection of ink droplets from the recording head 1 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the main part showing the ink droplet ejection state of the ink jet recording head.

  As shown in FIG. 3A, a state in which the rectifying plate 30 is moved to the normal operation position by the moving unit 50 and an airflow is generated in the space 32 between the liquid ejection surface 12 and the rectifying plate 30 by the airflow generating unit 40. Thus, a pressure change is generated in the flow path 13 by a pressure generating means (not shown), and ink droplet ejection is started. As a result, the meniscus rises in a columnar shape from the nozzle opening 11, and an ink droplet A is ejected from the nozzle opening 11 by cutting off a part of the columnar shape as shown in FIG. At this time, the ink droplet A flies so as to extend the tail portion, and as shown in FIG. 3C, a part of the tail portion of the ink droplet A is torn off, so that the main droplet B (main droplet) and the small droplet portion are small. Separated into droplet C (satellite droplet). Further, the small droplet C is also generated when the ink droplet A is separated by separating a part of the columnar shape in FIG.

  As shown in FIG. 3 (d), the main droplet B ejected in this way has a larger mass than the small droplet C, so that the main droplet B is not swept away by the air current, and the mesh-shaped rectifying plate 30 has an opening. Pass through 31. In contrast, since the small droplet C has a smaller mass than the main droplet B, the small droplet C is moved to an area where the opening 31 of the rectifying plate 30 is not provided by the air current as shown in FIG. Land on the current plate 30. As a result, the small droplet C does not land on the ejection target medium, and the flying small droplet C is prevented from floating by turbulence and adhering to the meniscus of the nozzle opening 11 to destroy the meniscus. Can do. Accordingly, it is possible to suppress the deterioration of the print quality due to the influence of the small droplet C and improve the print quality.

  In addition, since the landing of the small droplet C on the ejection medium can be suppressed, the flying speed of the ink droplet A (main droplet B) can be increased. Incidentally, when the flying speed of the ink droplet A is increased, the tail becomes longer and many small droplets C are separated. In this embodiment, even if many small droplets C are generated, the small droplets C are generated. Since landing on the current plate 30 and landing on the ejection target medium can be suppressed, the flying speed of the ink droplet A (main droplet B) can be increased.

  Furthermore, since the landing of the small droplet C on the ejection medium can be suppressed, the relative movement speed between the ejection medium and the recording head 1 can be increased, and high-speed printing can be realized. Incidentally, when the relative moving speed of the ejection target medium and the recording head 1 is increased, turbulence is generated, and the generation of small droplets C and a lot of landing position deviation occur. However, in this embodiment, the small droplets C Is landed on the current plate 30, high-speed printing can be realized.

  Further, the flushing operation can be performed at a very high speed by moving the current plate 30 to the flushing operation position by the moving means 50. Specifically, as shown in FIG. 4, when the rectifying plate 30 moves to the flushing operation position, the frame portion 33 of the rectifying plate 30 and the nozzle opening 11 face each other, and droplets from the nozzle opening 11 due to the flushing operation. Will land on the frame 33.

  5A and 5B are diagrams schematically showing the landing position on the current plate 30, FIG. 5A shows the landing position at the normal operation position, and FIG. 5B shows the landing position as an example of the flushing operation position. Indicates. In this case, the rectifying plate 30 is moved in the direction in which the nozzle openings 11 are arranged side by side, but may be moved in a direction orthogonal to the direction in which the nozzle openings 11 are arranged, as shown in FIG. As described above, it may be moved in an oblique direction.

  Further, in the above-described example, the movement of FIGS. 5B to 5D is realized by moving the rectifying plate 30 in the surface direction. However, by tilting the rectifying plate 30, FIG. ) To (d) so that the landing positions can be realized.

  Thereby, the droplet by flushing operation | movement is reliably trapped by the frame part 33 of the baffle plate 30, and flushing operation | movement can be performed reliably. In addition, since the switching between the normal operation position and the flushing operation position of the rectifying plate 30 can be performed instantaneously, the flushing operation can be performed at a high speed, and high-speed printing can be supported.

  A plurality of such recording heads 1 are integrally fixed to constitute a head unit. Here, the head unit of this embodiment will be described with reference to FIG.

  The head unit 100 includes a plurality of recording heads 1 and a base plate 110 to which the plurality of recording heads 1 are fixed.

  The base plate 110 is made of a plate-like member such as stainless steel and has a holding hole 111 into which the liquid ejection surface 12 side of each recording head 1 is inserted. The holding hole 111 has an opening area slightly larger than the outer periphery of the recording head 1 on the liquid ejecting surface 12 side, and the opposite side of the recording head 1 from the liquid ejecting surface 12 is inserted into the holding hole 111 of the base plate 110 for recording. A flange portion 14 provided on the outer periphery of the head 1 is fixed to one surface of the base plate 110 via screws or the like.

  In the present embodiment, the plurality of recording heads 1 are arranged in parallel in the first direction Y, which is the direction in which the nozzle openings 11 are arranged. In addition, the column composed of a plurality of recording heads 1 arranged in parallel in the first direction Y has a direction (second direction) intersecting the direction in which the nozzle openings 11 are arranged in parallel (first direction Y). Two rows are arranged side by side in X). The two rows of the recording heads 1 arranged in parallel in the second direction X are arranged at positions slightly shifted from each other in the second direction X. That is, the two rows of the recording heads 1 constitute a head group so that the recording heads 1 are arranged in a staggered manner. In one head group, adjacent recording heads 1 have nozzle openings 11 at the end of the nozzle row of one recording head 1 and nozzle openings 11 at the end of the nozzle row of the other recording head 1. The nozzle openings 11 are provided in the same position in the direction in which the nozzle openings 11 are arranged (the first direction Y). Thus, printing can be performed in all regions by the two rows of recording heads 1 in the width direction intersecting the transport direction of the ejection target medium. In this embodiment, the head unit 100 is provided with two head groups composed of four ink jet recording heads 1.

  Such a head unit 100 is mounted on the ink jet recording apparatus 200. Here, the ink jet recording apparatus will be described with reference to FIG.

  An ink jet recording apparatus 200 that is an example of a liquid ejecting apparatus according to the present embodiment performs printing by fixing a head unit 100 (recording head 1) and transporting a recording sheet S such as paper that is an ejected medium. This is a so-called line type recording apparatus. Specifically, the ink jet recording apparatus 200 includes an apparatus main body 201, a head unit 100 that includes a plurality of recording heads 1 and is fixed to the apparatus main body 201, a conveyance unit 202 that conveys the recording sheet S, and a head. The platen 203 which supports the back surface side opposite to the printing surface of the recording sheet S which the unit 100 opposes is provided.

  The head unit 100 is fixed to the apparatus main body 201 so that the juxtaposed direction (first direction Y) of the nozzle openings 11 of the recording head 1 is a direction that intersects the conveyance direction of the recording sheet S.

  The transport unit 202 includes a first transport unit 204 and a second transport unit 205 provided on both sides of the head unit 100 in the transport direction of the recording sheet S.

  The first conveying unit 204 includes a driving roller 204a, a driven roller 204b, and a conveying belt 204c wound around the driving roller 204a and the driven roller 204b. Similarly to the first transport unit 204, the second transport unit 205 includes a driving roller 205a, a driven roller 205b, and a transport belt 205c.

  Driving means such as a driving motor (not shown) is connected to the driving rollers 204a and 205a of the first conveying means 204 and the second conveying means 205, and the conveying belt 204c, The recording sheet S is conveyed on the upstream side and the downstream side of the head unit 100 as the 205c is driven to rotate.

  In the present exemplary embodiment, the first conveying unit 204 and the second conveying unit 205 including the driving rollers 204a and 205a, the driven rollers 204b and 205b, and the conveying belts 204c and 205c are exemplified. You may further provide the holding means hold | maintained on the conveyance belts 204c and 205c. As the holding unit, for example, a charging unit that charges the outer peripheral surface of the recording sheet S may be provided, and the recording sheet S charged by the charging unit may be attracted onto the conveying belts 204c and 205c by the action of dielectric polarization. . Further, as a holding unit, a pressing roller may be provided on the conveying belts 204c and 205c, and the recording sheet S may be sandwiched between the pressing roller and the conveying belts 204c and 205c.

  The platen 203 is made of a metal or resin having a rectangular cross section provided between the first transport unit 204 and the second transport unit 205 so as to face the head unit 100. The platen 203 supports the recording sheet S conveyed by the first conveying unit 204 and the second conveying unit 205 at a position facing the head unit 100.

  The platen 203 may be provided with a suction unit that sucks the conveyed recording sheet S on the platen 203. Examples of the suction means include a device that sucks and sucks the recording sheet S and a device that electrostatically sucks the recording sheet S by electrostatic force.

  Further, although not shown, each storage head 1 of the head unit 100 is connected to an ink storage means such as an ink tank or an ink cartridge in which ink is stored so as to be able to supply ink. For example, the ink storage unit may be held on the head unit 100 or may be held at a position different from the head unit 100 in the apparatus main body 201.

  In such an ink jet recording apparatus 200, the recording sheet S is transported by the transport unit 204, and printing is performed on the recording sheet S supported on the platen 203 by the head unit 100. The printed recording sheet S is conveyed by the conveying unit 202.

  In such printing by the ink jet recording apparatus 200, the recording head 1 is provided with the covers 20 that cover the liquid ejection surface 12 on both sides in the conveyance direction of the recording sheet S. Occurrence in the vicinity of the liquid ejection surface 12 can be suppressed. In particular, the recording head 1 of the present embodiment is mounted on the ink jet recording apparatus 200 so that the covers 20 are arranged on both sides in the transport direction, and thus covers the wind (airflow) generated when the recording sheet S is transported. 20 can be effectively suppressed. Incidentally, when the pair of covers 20 is provided as in the present embodiment, the direction of the airflow generated by the airflow generation means 40 may be defined by the direction in which the cover 20 is provided.

  Further, since the rectifying plate 30 is provided so as to shield the conveyance region of the recording sheet S and the liquid ejecting surface 12, the air flow from the recording sheet S side is also shielded by the rectifying plate 30, and the liquid ejecting surface. The generation of air current in the vicinity of 12 can be suppressed.

  In this way, the influence of the airflow due to the conveyance of the recording sheet S to the space 32 between the liquid ejecting surface 12 and the rectifying plate 30 is suppressed, and the landing position of the small droplet C by only the airflow generated by the airflow generating means 40. Therefore, the small droplet C can be landed by the rectifying plate 30.

  In the present embodiment, the head unit 100 having a plurality of recording heads 1 is mounted on the ink jet recording apparatus 200. However, the present invention is not limited to this, and one or a plurality of recording heads 1 are directly connected to the ink jet recording apparatus. You may mount in the apparatus 200. FIG. A plurality of head units 100 may be mounted on the ink jet recording apparatus 200.

(Embodiment 2)
FIG. 8 is a bottom view of the head unit according to the second embodiment of the invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 8, the head unit 100A of the present embodiment includes a plurality of recording heads 1A and a base plate 110.

  The head body 10 is fixed to each of the holding holes 111 of the base plate 110. In the present embodiment, two head groups 2 having the head main bodies 10 (two rows of head main bodies 10) arranged in a staggered manner are provided, as in the first embodiment. This head group 2 is one recording head 1A in this embodiment.

  Further, each head group 2 composed of two rows of head bodies 10 arranged in parallel in the second direction X is covered with a common cover 20A.

  The cover 20 </ b> A is provided for each recording head 1 </ b> A, and a pair of covers 20 </ b> A are provided continuously in the direction in which the plurality of head bodies 10 are arranged in the same direction (the same direction as the direction in which the nozzle openings 11 are arranged in parallel). It consists of a plate-shaped member. In the present embodiment, the cover 20A is provided on both sides in the second direction X of each recording head 1A (head group 2).

  Further, each recording head 1A (head group 2) of the head unit 100A is provided with one rectifying plate 30A common to each head body 10.

  The rectifying plate 30A is provided opposite to the liquid ejecting surfaces 12 of the plurality of head main bodies 10, and during normal operation, the opening 31 of the rectifying plate 30A is the same as in the first embodiment. The head openings 10 are provided at positions opposite to the nozzle openings 11 of all the head main bodies 10. Therefore, the normal operation position and the flushing operation position can be switched with respect to the plurality of head main bodies 10 by moving the current plate 30A by a moving means (not shown). The frame portion 33 of the rectifying plate 30A is located at a position opposite to the nozzle openings 11 of all the head main bodies 10 in the same manner as in the first embodiment.

  Furthermore, each recording head 1A (head group 2) is provided with an airflow generating means 40A composed of a blower, and generates an airflow between the liquid ejection surfaces 12 of the plurality of head bodies 10 and the rectifying plates 30A. Let

  In such a configuration, it is not necessary to provide the cover 20, the rectifying plate 30, the airflow generating means 40, and the moving means 50 for each head body 10 as in the first embodiment described above, and the cost is reduced by reducing the number of parts. can do.

  Further, in this embodiment, the cover 20A, the rectifying plate 30A, and the airflow generating means 40A are provided for each recording head 1A (head group 2). However, the present invention is not limited to this, and is common to a plurality of head groups 2. You may make it provide a cover, a baffle plate, and an airflow generation means. In this case, the head unit 100A itself can be a recording head.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the basic composition of this invention is not limited to what was mentioned above.

  In the above-described embodiment, the rectifying plates 30 and 30A are movable with respect to the cover 20. However, the rectifying plate and the cover 20 are integrated, and these can be moved with respect to the head body, so that the rectifying plate is in the normal operation position. Further, it may be movable to the flushing operation position.

  Moreover, in Embodiment 1 mentioned above, although mesh-shaped material was used as the rectifying plates 30 and 30A, as described above, the material and shape of the rectifying plates 30 and 30A are not particularly limited thereto. Absent. Here, the other example of a baffle plate is shown in FIG. FIG. 9 is a bottom view of an ink jet recording head showing a modification of the rectifying plate according to another embodiment.

  As shown in FIG. 9A, the rectifying plate 30 </ b> B is made of a plate-like member, and is provided with one slit-like opening 31 </ b> B that faces the plurality of nozzle openings 11. In such a rectifying plate 30B, when an air flow is generated in the longitudinal direction of the slit-shaped opening 31B, the small droplets C pass through the slit-shaped opening 31B and land on the ejection target medium (recording sheet S). For this reason, an air flow may be generated along the short direction of the slit-shaped opening 31B. Accordingly, the communication hole 21 </ b> A may be provided in the cover 20 </ b> B covering the rectifying plate 30 </ b> B in a direction intersecting with the direction in which the nozzle openings 11 are arranged in parallel.

  The movement direction of the rectifying plate 30B during the flushing operation may be a direction along the short direction of the slit-shaped opening 31B.

  9B, the rectifying plate 30C has one slit hole 34 facing the plurality of nozzle openings 11, and the rectifying plate 30 having the opening 31 is fixed in the slit hole 34. Has been. That is, the rectifying plate 30C shown in FIG. 9B expands the opening area of the slit-shaped opening 31B of the rectifying plate 30B shown in FIG. 9A, and the rectifying plate 30 of the first embodiment described above is fixed therein. Has the structure. In such a rectifying plate 30C, the air flow may be generated along the direction in which the nozzle openings 11 are arranged side by side, or may be generated along the direction intersecting with the direction in which the nozzle openings 11 are arranged side by side. Is no longer restricted.

  In each of the embodiments described above, the airflow generation means 40 and 40A are provided in the recording heads 1 and 1A. However, the present invention is not particularly limited thereto. For example, one airflow generation means is provided for each of the head units 100 and 100A. Alternatively, the ink jet recording apparatus 200 may be provided with an air flow generation means.

  In addition, as the airflow generation means 40 and 40A of each of the above-described embodiments, for example, a humid airflow may be generated. In order to generate such a humid airflow, a humidifier or the like may be provided. In this way, the airflow generation means generates a humid airflow, thereby suppressing the drying of the liquid near the nozzle opening from being accelerated by the airflow generated by the airflow generation means, and drying and curing the liquid. It is possible to reduce the ejection failure due to.

  In the first and second embodiments described above, as the ink jet recording apparatus 200, the recording head 1, 1A (head unit 100) is fixed, and printing is performed simply by transporting the recording sheet S. Although the recording apparatus 200 has been illustrated, the present invention is not particularly limited thereto. For example, a serial type ink jet type that performs printing while moving the recording heads 1 and 1A (head unit 100) in the main scanning direction with respect to the ejection target medium. The present invention can also be applied to a recording apparatus.

  In the above embodiment, an ink jet recording head has been described as an example of a liquid ejecting head, and an ink jet recording apparatus has been described as an example of a liquid ejecting apparatus. The present invention is intended for the entire apparatus, and can of course be applied to a liquid ejecting head and a liquid ejecting apparatus that eject liquid other than ink. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bio-organic matter ejection head used for biochip production, and the like, and can also be applied to a liquid ejection apparatus provided with such a liquid ejection head.

  A ink droplet, B main droplet, C small droplet, 1, 1A inkjet recording head (liquid ejecting head), 2 head group, 10 head main body, 11 nozzle opening, 12 liquid ejecting surface, 20, 20A, 20B cover, 30, 30A, 30B, 30C Current plate, 31, 31B Opening, 40, 40A Airflow generating means, 50 Moving means, 100, 100A Head unit, 110 Base plate, 200 Inkjet recording apparatus (liquid ejecting apparatus)

Claims (9)

A head body having a nozzle opening for ejecting liquid;
A cover provided around the liquid ejecting surface where the nozzle opening is opened and protruding in the liquid ejecting direction;
A rectifying plate provided in a position away from the liquid ejection surface in the cover and having an opening in a region opposite to the nozzle opening;
An airflow generating means for generating an airflow along the surface direction of the liquid ejecting surface between the current plate and the liquid ejecting surface;
The liquid jet head, wherein the rectifying plate is provided so as to be movable in at least one of the surface directions of the liquid ejecting surface or in a direction inclined with respect to the surface direction.   The liquid jet head according to claim 1, wherein the current plate is movable together with the cover.   The liquid jet head according to claim 1, wherein at least a surface of the baffle plate is formed of an adsorbent material.   The liquid ejecting head according to claim 1, further comprising a moving unit that positions and moves the current plate.   The liquid ejecting head according to claim 1, further comprising a plurality of the head main bodies, wherein the cover is continuously provided around the plurality of head main bodies.   The liquid jet head according to claim 1, wherein the air flow generation unit generates a gas flow of moisture.   A liquid ejecting head unit comprising two or more liquid ejecting heads according to claim 1.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.   A liquid ejecting apparatus comprising the liquid ejecting head unit according to claim 7.

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