JP2011168032A - Liquid ejection head, liquid ejection head unit, and liquid ejector - Google Patents

Abstract

A liquid ejecting head, a liquid ejecting head unit, and a liquid ejecting apparatus capable of improving print quality by suppressing landing of small droplets on an ejection target medium and suppressing liquid ejection failure due to small droplets. I will provide a.
A head main body 10 having a nozzle opening 11 for ejecting liquid, a cover 20 provided around a liquid ejecting surface 12 in which the nozzle opening 11 is opened and projecting in the liquid ejecting direction, and the cover 20, a current plate 30 provided at a position away from the liquid ejecting surface 12 and provided with an opening in a region opposite to the nozzle opening 11, and between the liquid ejecting surface 12 and the current plate 30. The air flow generating means 40 for generating the air flow along the surface direction of the liquid ejecting surface and the exposed openings 51 having an opening area larger than at least the liquid ejecting surface 12 are arranged in parallel at predetermined intervals, and the rectification is performed. A water absorbing member 50 slidably provided on at least a surface of the plate 30 facing the liquid ejecting surface 12.
[Selection] Figure 2

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).

Japanese Patent Laid-Open No. 5-16370 Japanese Patent Laid-Open No. 2000-62166

  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.

  Such a problem exists not only in an ink jet recording head that ejects ink, but also in a liquid ejecting head that ejects liquid other than ink.

  In view of such circumstances, the present invention suppresses the landing of small droplets on an ejection target medium, suppresses liquid ejection defects due to small droplets, and improves the print quality. An object is to provide an ejection head unit and a liquid ejection apparatus.

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 opposite to the nozzle opening, and the liquid ejection between the liquid ejection surface and the rectification plate An airflow generating means for generating an airflow along the surface direction of the surface and an exposed opening having an opening area larger than at least the opening of the rectifying plate are arranged in parallel at a predetermined interval, and at least the liquid of the rectifying plate And a water-absorbing member slidably provided on a surface opposite to the ejection surface.
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, since the liquid adhering to the current plate can be absorbed and removed by the water absorbing member, ejection failure due to the formation of a liquid meniscus at the opening can be suppressed, and the liquid adhering to the current plate can be prevented at an unexpected timing. It can suppress falling.

  Here, it is preferable to further comprise a moving means for sliding the water absorbing member on the surface of the rectifying plate in the direction in which the exposed openings are arranged. According to this, since the water absorbing member can be moved by the moving means, it is possible to easily remove the water absorbed by the water absorbing member.

  In addition, it is preferable that the water absorbing member is slidably provided on each of the liquid ejection surface side surface of the rectifying plate and a surface opposite to the liquid ejection surface. According to this, the liquid adhering to the current plate can be reliably absorbed and removed, and deformation caused by pressing the water absorption member of the current plate can be suppressed.

  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.

  The rectifying plate is preferably made of a mesh material. According to this, 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. 3 is a plan view of a water absorbing member according to Embodiment 1. FIG. 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. 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. FIG. 6 is a cross-sectional view of a main part of a recording head according to a second embodiment. 6 is a perspective view of a water absorbing member according to Embodiment 2. FIG. FIG. 6 is a bottom view of a head unit according to a third embodiment. It is a top view which shows the modification of the baffle plate which concerns on other embodiment.

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 according to this embodiment includes a head body 10 and a cover that surrounds 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 the liquid ejection surface 12 side of the head body 10 is inserted into one opening and fixed to the side surface of the head body 10. It is integrated with the head body 10. 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. Thus, since the cover 20 covers the flying region, the opening of the cross section in the same direction as the surface direction of the liquid ejecting surface 12 of the cover 20 is the liquid ejecting surface 12 (for example, a nozzle plate provided with the nozzle openings 11). It is preferable to have a size with a larger area.

  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 forming a grid of metal, resin, fiber, nonwoven fabric, paper, or the like. The mesh member made 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 water-absorbing material as the rectifying plate 30, when the ink adheres to the rectifying plate 30, the ink is absorbed and held by the rectifying plate 30 having the water absorbing property, and the ink attached to the rectifying plate 30. Can be prevented from dropping and adhering to the ejected 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 is likely to land at a position deviated from directly below the nozzle opening 11 due to being greatly affected by the deviation of the ejection direction and the air flow as it leaves the nozzle opening 11. For this reason, if the rectifying plate 30 is separated from the liquid ejecting surface 12, the positional deviation increases, so that 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.

  The space 32 between the current plate 30 and the liquid ejection surface 12 is externally provided by a pair of insertion holes 22 provided so as to face each other on the side surfaces of the cover 20 on both sides of the nozzle opening 11 in the parallel direction. 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 insertion hole 21 on the outer periphery of the cover 20 opens.

  As a result, gas is blown from the airflow generation means 40 into the cover 20 through the one insertion 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 insertion 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.

  Further, the cover 20 is provided with a water absorbing member 50 slidably provided on the current plate 30. The water absorbing member 50 is made of a material having water absorption, for example, a water absorbing sheet or a porous material, and as shown in FIG. 3, the exposed openings 51 having an opening area slightly larger than the liquid ejecting surface 12 have a predetermined interval. It is provided with a plurality. FIG. 3 is a plan view showing the water absorbing member. The exposure opening 51 only needs to be provided with an opening area that allows ink droplets ejected from the nozzle opening 11 to pass through the opening 31 of the rectifying plate 30. It suffices if the opening area is larger than 30 openings 31.

  As shown in FIGS. 1 and 2, such a water absorbing member 50 slides on the surface of the rectifying plate 30 on the liquid ejection surface 12 side by a pair of rollers 60 and 61 that are rotatably provided outside the cover 20. So that it is held. Specifically, the water absorbing member 50 is wound around one roller 60, and the tip thereof is wound around the other roller 61 so that the water absorbing member 50 is held between the pair of rollers 60 and 61. In addition, the pair of rollers 60 and 61 are provided on the ink ejection direction side (the side opposite to the head body 10) from the rectifying plate 30, so that the water absorbing member 50 stretched between the pair of rollers 60 and 61 is provided. The rectifying plate 30 is pressed with a predetermined pressure toward the surface facing the liquid ejection surface 12.

  In the present embodiment, one roller 60 is provided with a driving means 62 such as a driving motor that rotationally drives the roller 60. That is, the pair of rollers 60 and 61 and the driving unit 62 function as a moving unit that moves the water absorbing member 50 so as to be in sliding contact with the current plate 30.

  And the opening 31 of the baffle plate 30 is exposed by moving the water absorption member 50 by rotation of the rollers 60 and 61, and arrange | positioning the exposure opening part 51 provided in the water absorption member 50 on the baffle plate 30. FIG. In a state where the opening 31 is exposed by the exposure opening 51 as described above, ink is ejected from the nozzle opening 11, thereby passing the ink droplet (main droplet) through the exposure opening 51 and the opening 31, and the ejected medium Can land on. When the ink ejection is completed, the water absorption member 50 is wound on the roller 60 by rotating the roller 60, and the water absorption member 50 is slidably contacted with the rectifying plate 30. In this region, the ink adhering to the current plate 30 can be absorbed.

  Here, the ejection of ink droplets from the recording head 1 will be described more specifically with reference to FIGS. 4 and 5. FIG. 4 and 5 are cross-sectional views of the main part showing the ink droplet ejection state of the ink jet recording head.

  As shown in FIG. 4A, the water absorbing member 50 is moved so that the exposed opening 51 faces the liquid ejection surface 12, that is, the rectifying plate 30 is exposed by the exposed opening 51, and the air flow In the state where the air flow is generated in the space 32 between the liquid ejecting surface 12 and the rectifying plate 30 by the generating means 40, the pressure generating means (not shown) causes a pressure change in the flow path 13 to start the ejection of ink droplets. To do. 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 in the form of extending the tail, and as shown in FIG. 4C, a part of the tail of the ink droplet A is torn off, so that the main droplet B (main droplet) and the small droplet 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. 4 (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 an air current, and the mesh-shaped rectifying plate 30 has an opening. Pass through 31. The main droplet B that has passed through the opening 31 lands on a desired position of the ejection target medium. On the other hand, since the small droplet C has a smaller mass than the main droplet B, the small droplet C is moved to a region where the opening 31 of the rectifying plate 30 is not provided by the air current and landed on the rectifying 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.

  When the ink ejection is completed, the water absorbing member 50 is slid on the surface of the rectifying plate 30 on the liquid ejection surface 12 side as shown in FIG. As a result, the region between the adjacent exposed openings 51 of the water absorbing member 50 is in sliding contact with the surface of the rectifying plate 30 on the liquid ejection surface 12 side, and the ink (small droplet C) adhering to the rectifying plate 30 is removed. Water is absorbed by the water absorbing member 50 and removed. Thereafter, as shown in FIG. 5B, the next exposed opening 51 is arranged on the rectifying plate 30, so that ink can be ejected.

  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.

  As illustrated, 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 3. 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, as shown in FIG. 7, 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, and conveys a recording sheet S. Conveying means 202, and a platen 203 that supports the back side opposite to the printing surface of the recording sheet S facing each other of the head unit 100.

  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.

  At the time of printing, 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, so that the airflow during conveyance of the recording sheet S is in the vicinity of the liquid ejection surface 12. Can be suppressed.

  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 is suppressed in the space 32 between the liquid ejecting surface 12 and the rectifying plate 30, and the landing position of the small droplet C is determined only by the airflow generated by the airflow generating means 40. Since it can be controlled, the small droplet C can be landed by the current 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 cross-sectional view of an ink jet recording head which is an example of a liquid jet head according to Embodiment 2 of the present invention, and FIG. 9 is a perspective view showing a water absorbing member according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in the drawing, the ink jet recording head 1A (hereinafter also referred to as recording head 1A) of the present embodiment includes a head body 10, a cover 20, a current plate 30, an airflow generating means 40, and water absorbing members 50 and 50A. And.

  As shown in FIG. 9, the water absorbing member 50 is slid on the liquid ejecting surface 12 side of the rectifying plate 30 and adheres to the liquid ejecting surface 12 of the rectifying plate 30 as in the first embodiment. Remove by absorbing water.

  The water absorbing member 50A slides on the surface of the rectifying plate 30 opposite to the liquid ejecting surface 12, and absorbs and removes ink adhering to the surface of the rectifying plate 30 opposite to the liquid ejecting surface 12. To do. Specifically, the water absorbing member 50A has the same width as the juxtaposed direction of the nozzle openings 11 of the rectifying plate 30 and a direction (second direction) intersecting the juxtaposed direction (first direction Y) of the nozzle openings 11 X) is a long member, and the water absorbing member 50A is opposite to the liquid jet surface 12 side of the current plate 30 by two rollers 60A and 61A provided on both outer sides of the cover 20 in the second direction X. It is held so as to move in sliding contact with the surface. Incidentally, the two rollers 60 </ b> A and 61 </ b> A are provided closer to the liquid ejection surface 12 than the rectifying plate 30, so that the water absorbing member 50 </ b> A supported movably by the two rollers 60 </ b> A and 61 </ b> A The surface opposite to the surface 12 is pressed with a predetermined pressure.

  Also, like the roller 60 of the water absorbing member 50, one roller 60A is provided with driving means 62A such as a driving motor that rotationally drives the roller 60A, and the water absorbing member 50A is driven by the driving means 62A. You can move at the timing.

  As described above, the water absorbing members 50 and 50A are slidably provided on both surfaces of the rectifying plate 30, so that the ink adhering to both surfaces of the rectifying plate 30 can be reliably removed by the two water absorbing members 50 and 50A. Therefore, it is possible to prevent the ink attached to the current plate 30 from dropping on the recording sheet S, which is the ejected medium, at an unexpected timing and degrading the print quality.

  Further, by bringing the water absorbing members 50 and 50A into contact with each other from both sides of the current plate 30 with a predetermined pressure, deformation of the current plate 30 by the water absorbing members 50 and 50A can be suppressed, and the opening 31 is relative to the nozzle opening 11. It is possible to suppress the deviation from the facing position.

(Embodiment 3)
FIG. 10 is a bottom view of the head unit according to the third 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. 10, the head unit 100 </ b> A of this embodiment includes a plurality of recording heads 1 </ b> B 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 1B 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> B, and a pair of covers 20 </ b> A 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 1B (head group 2).

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

  The rectifying plate 30 </ b> A is provided opposite to the liquid ejection surfaces 12 of the plurality of head main bodies 10. Note that the opening 31 of the rectifying plate 30A is provided at a position opposite to the nozzle openings 11 of all the head bodies 10 as in the first embodiment.

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

  Each recording head 1B (head group 2) is provided with a water absorbing member 50B slidably provided on the liquid ejection surface 12 of the rectifying plate 30A by a pair of rollers 60B and 61B. The water absorbing member 50B is provided so as to be movable in the direction in which the nozzle openings 11 are arranged in the same manner as the water absorbing member 50 of the first embodiment described above. The water absorbing member 50B is provided in common to all the head main bodies 1 constituting the recording head 1B (head group 2).

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

  In this embodiment, the cover 20A, the rectifying plate 30A, the airflow generating means 40A, and the water absorbing member 50B are provided for each recording head 1B (head group 2). However, the present invention is not limited to this, and a plurality of head groups is provided. The cover, the current plate, the airflow generating means, and the water absorbing member common to 2 may be provided. 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.

  For example, in each of the above-described embodiments, the cover 20, 20A has been exemplified as a rectangular tube-shaped member having a rectangular opening on the recording sheet S side. However, the present invention is not particularly limited thereto, and for example, as the covers 20-20A A cylindrical member may be used.

  Further, for example, in each of the above-described embodiments, a mesh-like material is used as the rectifying plates 30 and 30A. However, as described above, the material and shape of the rectifying plates 30 and 30A are particularly limited to this. It is not a thing. Here, the other example of a baffle plate is shown in FIG. FIG. 11 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. 11A, the rectifying plate 30 </ b> B is made of a plate-like member, and is provided with one slit-like opening 31 </ b> A 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 31A, the small droplets C pass through the slit-shaped opening 31A and land on the ejection target medium (recording sheet S). For this reason, an airflow may be generated along the short direction of the slit-shaped opening 31A. Therefore, the cover 20B covering the rectifying plate 30B may be provided with the insertion holes 21A on both sides in the direction in which the nozzle openings 11 are arranged in parallel.

  Further, as shown in FIG. 11B, the rectifying plate 30 </ b> C has one slit hole 33 opposed to the plurality of nozzle openings 11, and the rectifying plate 30 having the opening 31 is fixed in the slit hole 33. Has been. That is, the rectifying plate 30C shown in FIG. 11 (b) increases the opening area of the slit-shaped opening 31A of the rectifying plate 30B shown in FIG. 11 (a), and fixes the rectifying plate 30 of the first embodiment described above 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 not limited.

  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 each of the above-described embodiments, as the ink jet recording apparatus 200, a so-called line type ink jet recording apparatus that performs printing only by fixing the recording heads 1 to 1A (head unit 100) and transporting the recording sheet S. 200 is exemplified, but the present invention is not particularly limited thereto. For example, a serial type ink jet recording apparatus that performs printing while moving the recording heads 1 to 1A (head unit 100) in the main scanning direction with respect to the ejection target medium. The present invention can also be applied to.

  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, 1B inkjet recording head (liquid ejecting head), 2 head group, 10 head body, 11 nozzle opening, 12 liquid ejecting surface, 20, 20A, 20B Cover, 21, 21A insertion hole, 30, 30A, 30B, 30C Current plate, 31, 31A opening, 40 Airflow generating means, 50, 50A, 50B Water absorbing member, 60-60B, 61-61B Roller, 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 ejection surface between the liquid ejection surface and the rectifying plate;
Exposed openings having an opening area wider than at least the opening of the rectifying plate are arranged in parallel at a predetermined interval, and are provided to be slidable on at least a surface of the rectifying plate facing the liquid ejection surface. A liquid ejecting head comprising: a water absorbing member.   The liquid ejecting head according to claim 1, further comprising a moving unit that slides the water absorbing member on a surface of the rectifying plate in a direction in which the exposed openings are arranged.   The said water absorption member is provided in each of the surface by the side of the said liquid ejection surface of the said baffle plate, and the surface on the opposite side to the said liquid ejection surface, It is characterized by the above-mentioned. The liquid jet head described.   The liquid ejecting head according to claim 1, further comprising a plurality of the head main bodies, wherein the cover is provided continuously around the plurality of head main bodies.   The liquid jet head according to claim 1, wherein the current plate is made of a mesh material.   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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