JP2005313637A - Droplet ejection apparatus, ink-jet printer, and droplet moving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet ejection apparatus and an ink-jet head which can reduce wipe execution frequency. <P>SOLUTION: A water repellent layer 130 is formed on an ink ejection surface 129 of the ink-jet head. The water repellent layer 130 has a first water repellent layer 141 which is formed along the arrangement direction of a plurality of nozzles 109, and a plurality of second water repellent layers 142 which are arranged so as to sandwich the first water repellent layer 141. In the ink ejection surface 129, hydrophilic areas 128a to 128e are formed in which the water repellent layer 130 is not formed. The plurality of second water repellent layers 142 are spaced away from each other in the direction orthogonal to the arrangement direction of the nozzles. Boundary lines 152 of ends 142a of the second water repellent layers 142 in the first water repellent 141 side with the hydrophilic areas 128a to 128d have a zigzag shape. Ink droplets adhered to the ink ejection surface 129 readily attain a critical angle when passing through the boundary lines 152. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a droplet ejection device that ejects droplets, an inkjet printer, and a droplet movement device that moves droplets.

  Patent Document 1 describes a liquid ejection apparatus in which a liquid repellent treatment groove having a deteriorated liquid repellency is formed in a liquid repellent treatment layer formed around the ejection hole of a nozzle that ejects liquid. In this liquid ejection apparatus, the liquid repellent treatment groove is carved around the nozzle ejection hole. As a result, when the droplets retained on the liquid-repellent treatment layer around the nozzle ejection hole without being scattered while being ejected from the nozzle gradually become larger due to repeated droplet ejection from the nozzle, Since the enlarged droplet is drawn into the liquid processing groove, it is possible to exclude the enlarged droplet from the periphery of the nozzle discharge hole. Accordingly, it is possible to prevent a discharge failure caused by a droplet remaining in the discharge hole of the nozzle.

JP 2002-86021 A

  However, in the liquid ejecting apparatus described in Patent Document 1, the droplets drawn into the liquid repellent treatment groove stay in the droplet treatment groove. Since the staying liquid droplets overflow later, it is necessary to remove the liquid droplets held around the nozzle discharge holes by wiping with a blade or the like. When the wiping operation increases, there arises a problem that the liquid repellent treatment layer gradually deteriorates due to wear.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid droplet ejecting apparatus and an ink jet head that can reduce the frequency of wiping.

  Furthermore, an object of the present invention is to provide a droplet moving device that can remove droplets attached to a droplet adhesion surface from the droplet adhesion surface.

Means for Solving the Problems and Effects of the Invention

  The droplet ejecting apparatus of the present invention includes a plurality of first regions and a space between two adjacent first regions on a droplet ejection surface provided with a nozzle row composed of a plurality of nozzles that eject droplets. And a second region having higher liquid repellency than the first region located adjacent to these regions. The first force required when the liquid droplets existing in the first region adjacent to the second region closer to the nozzle row enter the second region is the first force. It is smaller than the second force required when the droplet existing in the first region adjacent to the region away from the nozzle row with respect to the second region enters the second region.

  The ink jet printer according to the present invention includes an ink jet head provided with a nozzle array composed of a plurality of nozzles that eject ink on an ink ejection surface, and a medium transport that transports a medium on which the ink ejected from the plurality of nozzles lands. Means, and reciprocating means for reciprocating the ink jet head in a direction orthogonal to the extending direction of the nozzle rows. The ink jet head is adjacent to the two first regions extending between the two first regions on the ink discharge surface along the extending direction of the nozzle row. However, a second region extending in the extending direction of the nozzle row and having higher liquid repellency than the first region is formed, and the nozzle row is formed with respect to the second region. A first force required when an ink droplet existing in the first region adjacent in the approaching direction enters the second region is adjacent to the second region in a direction away from the nozzle row. The ink drop present in the first area is smaller than the second force required when entering the second area.

  Thereby, the droplet adhering to the droplet discharge surface can be moved away from the nozzle by the inertial force or the force received from the air. As a result, the frequency of wiping the droplet discharge surface can be reduced. Therefore, the droplet discharge surface can have a long life, and when used in a serial printer, the printing speed can be increased.

  In the present invention, the first region and the second region preferably extend along the extending direction of the nozzle row. Thereby, the formation of the first region and the second region can be facilitated, and the droplets can be easily moved away from the nozzle row.

  In the present invention, it is preferable that a plurality of first regions and at least one or more second regions are respectively formed on both sides of the nozzle row. This is effective in a serial printer in which the direction of the force received from the air is alternately switched.

  In the present invention, it is preferable that a plurality of second regions are provided, and the plurality of first regions and the plurality of second regions are alternately formed while being adjacent to each other. Thereby, a droplet can be kept further from a nozzle.

  In the present invention, the nozzles constituting the nozzle row are formed in a third region having the same liquid repellency as the second region, and the third region is between these two first regions. It is preferable to be located adjacent to the region. As a result, almost no liquid droplets remain around the nozzle.

  In the present invention, it is preferable that the first and second regions extend annularly so as to surround the nozzle. As a result, the droplets can be moved away from the direction in which the nozzle rows extend.

  At this time, the boundary line between the first region and the third region adjacent to the first region closer to the nozzle row is a straight line parallel to the extending direction of the nozzle row, The boundary line between one region and the second region adjacent to the first region away from the nozzle row is symmetric with respect to a line including portions having different inclination angles or the extending direction of the nozzle row Alternatively, two line segments that are inclined may be alternately continuous. As a result, when the droplet moves in a direction away from the nozzle, the rising angle of the droplet easily reaches the limit angle when entering the second region from the first region. Therefore, it becomes easy to move the droplet in a direction away from the nozzle. Further, when the liquid droplet moves in the direction approaching the nozzle, the liquid droplet hardly enters the second region.

  In the present invention, the liquid repellency of the second region is higher than that of the first region so that the liquid repellency is improved stepwise in the direction perpendicular to the extending direction of the nozzle row and away from the nozzle row. It is preferable that a plurality of areas having high properties are provided. In the present invention, in the second region, many portions having lower or higher liquid repellency than the second region are formed, and portions having lower or higher liquid repellency in the second region are formed. It is preferable that the average density of the portion gradually decreases or increases in a direction perpendicular to the extending direction of the nozzle row and away from the nozzle row. Thereby, when the droplet moves in the direction away from the nozzle, the droplet easily enters the second region from the first region, and when the droplet moves in the direction approaching the nozzle, the second This makes it difficult for the droplets to enter the region. Therefore, it becomes easy to move the droplet in a direction away from the nozzle.

  A plurality of nozzle rows are provided, and a fourth region and a fourth region are provided between two third regions formed for the nozzles constituting the two adjacent nozzle rows. The fifth regions adjacent to each other and having higher liquid repellency than the fourth region are alternately formed in the extending direction of the nozzle row while extending in a direction perpendicular to the extending direction of the nozzle row. Good. At this time, each of all the fifth regions formed between the two third regions is present in the fourth region adjacent to one side in the nozzle row extending direction with respect to the fifth region. When the ink droplet to be moved enters the fifth region, the force required for the fifth region to be present in the fourth region adjacent to the other side in the extending direction of the nozzle row with respect to the fifth region is the fifth. Preferably, it is less than the force required to enter the region. Alternatively, a plurality of nozzle rows are provided, and between the third regions formed for the nozzles constituting the two adjacent nozzle rows, the fourth region and the fourth region The fifth regions adjacent to the region and having higher liquid repellency than the fourth region are alternately formed in the extending direction of the nozzle row while extending in a direction perpendicular to the extending direction of the nozzle row. It's okay. At this time, among all the fifth regions formed between the two third regions, adjacent to each other including one of the two fifth regions formed on the outermost sides in the extending direction of the nozzle row In the first group of the fifth area, it is necessary when the droplets existing in the fourth area adjacent to the inside in the extending direction of the nozzle row enter the fifth area with respect to the fifth area. The force is smaller than the force required when droplets existing in the fourth region adjacent to the outside in the extending direction of the nozzle row enter the fifth region with respect to the fifth region, In the second group of fifth regions adjacent to each other including the other of the two fifth regions formed on the outermost sides in the extending direction, adjacent to the inner side in the extending direction of the nozzle row with respect to the fifth region When a droplet existing in the fourth region enters the fifth region The required force may be smaller than the force required when a droplet existing in the fourth region adjacent to the outside in the extending direction of the nozzle row enters the fifth region with respect to the fifth region. preferable. Thereby, even if it is a case where the some nozzle row is mutually spaced apart, a droplet can be kept away from each nozzle row.

  In the present invention, it is preferable that the droplet absorber is disposed further on the side farther from the nozzle row than the second region formed farthest from the nozzle row. At this time, the droplet absorbers may be arranged outside the second region formed at the outermost side and outside the fifth region formed at the outermost side. Thereby, the droplet moved in the direction away from the nozzle can be absorbed by the droplet absorber. Therefore, it is possible to prevent droplets from dropping from the droplet discharge surface.

  Further, the reciprocating means may move the ink jet head at a speed at which wind force is applied to the ink droplet that is larger than the first force and smaller than the second force. Accordingly, it is possible to apply a predetermined wind force to the droplets using the reciprocating means, and it is not necessary to add a special configuration for applying the wind force to the droplets, so that the manufacturing cost of the ink jet printer does not increase.

  The droplet moving device according to the present invention is a droplet moving device that moves the droplets adhering to the droplet adhering surface using wind force or inertial force, and alternates along the predetermined direction on the droplet adhering surface. The first region and the second region having higher liquid repellency than the first region are adjacent to each other without any gap. Then, the first force required when the droplet existing in the first region adjacent to the second region on the side in the predetermined direction enters the second region is applied to the second region. Therefore, the second force required when the droplet existing in the first region adjacent to the side opposite to the predetermined direction enters the second region is smaller than the second force. Thereby, the droplet adhering to the droplet adhering surface can be moved in a predetermined direction by an inertial force or a force received from the air. Therefore, it is possible to remove the droplets attached to the droplet adhesion surface from the droplet adhesion surface.

  The droplet ejecting apparatus of the present invention includes a droplet discharge surface, a nozzle that is formed on the droplet discharge surface and discharges a droplet, a first region formed on the droplet discharge surface, and a first region formed on the droplet discharge surface. And a second region having higher liquid repellency than the first region sandwiched between the first regions. The first force required for the droplet to enter the second region when the droplet is present in an area closer to the nozzle than the second region in the first region is Less than the second force required for the droplet to enter the second region when the droplet is in an area farther from the nozzle than the second region.

  According to this, a droplet that adheres to the droplet discharge surface and receives inertial force or wind force can be moved away from the nozzle. As a result, the frequency of wiping the droplet discharge surface can be reduced. Therefore, the droplet discharge surface can have a long life, and when used in a printer, the printing speed can be increased.

  In the droplet ejection device of the present invention, the second region may have a ring shape surrounding the nozzle. According to this, a droplet can be kept away from the nozzle in any direction with respect to the nozzle.

  In the liquid droplet ejecting apparatus of the present invention, an area closer to the nozzle than the second area in the first area may have an annular shape surrounding the nozzle. According to this, a droplet can be kept away from the nozzle in any direction with respect to the nozzle.

  The liquid droplet ejecting apparatus of the present invention further includes a third region that has the same liquid repellency as the second region and is closer to the nozzle than the second region. A first region may exist between the three regions. According to this, since the third region exists around the nozzle, no droplet remains around the nozzle.

  At this time, the boundary between the first region and the third region may be defined by a straight line or a smooth curve. According to this, when the droplet moves in the direction approaching the nozzle, the droplet does not easily enter the third region.

  In the droplet ejecting apparatus of the present invention, the boundary between the second region and the first region is closer to the area closer to the nozzle than the second region is defined by a zigzag line. The boundary between the region in one region and the region farther from the nozzle than in the second region may be defined by a straight line or a smooth curve. According to this, when the liquid droplet moves in the direction away from the nozzle, the rising angle of the liquid droplet easily reaches the limit angle when entering the second area from the first area. Therefore, it becomes easy to move the droplet in a direction away from the nozzle. Further, when the liquid droplet moves in the direction approaching the nozzle, the liquid droplet hardly enters the second region.

  Further, in the droplet ejecting apparatus of the present invention, the liquid repellency is stepwise in the direction away from the nozzle at the boundary between the second region and the region closer to the nozzle than the second region in the first region. A plurality of areas having higher liquid repellency than the first region may be provided so as to improve. According to this, when the droplet moves in the direction away from the nozzle, the droplet easily enters the second region from the first region, and when the droplet moves in the direction approaching the nozzle, It becomes difficult for the droplets to enter the region 2. Therefore, it becomes easy to move the droplet in a direction away from the nozzle.

  In the liquid droplet ejecting apparatus of the present invention, there are many portions having lower liquid repellency than the second region at the boundary between the second region and the region closer to the nozzle than the second region in the first region. The average density of the portion that is formed and has low liquid repellency in the second region may gradually decrease in the direction away from the nozzle row. According to this, when the droplet moves in the direction away from the nozzle, the ink droplet easily enters the second region from the first region, and when the droplet moves in the direction approaching the nozzle, It becomes difficult for the droplets to enter the region 2. Therefore, it becomes easy to move the droplet in a direction away from the nozzle.

  In the liquid droplet ejecting apparatus of the present invention, there are many portions having higher liquid repellency than the second region at the boundary between the second region and the region closer to the nozzle than the second region in the first region. The average density of the portion that is formed and has high liquid repellency in the second region may gradually increase in the direction away from the nozzle row. According to this, when the droplet moves in the direction away from the nozzle, the droplet easily enters the second region from the first region, and when the droplet moves in the direction approaching the nozzle, It becomes difficult for the droplets to enter the region 2. Therefore, it becomes easy to move the droplet in a direction away from the nozzle.

  In the droplet ejecting apparatus of the present invention, the liquid absorber may be disposed at a position farther from the nozzle than the first and second regions on the droplet ejection surface. According to this, the liquid absorber that has moved in the direction away from the nozzle can be absorbed by the liquid absorber. Therefore, it is possible to prevent droplets from dropping from the droplet discharge surface.

  In the droplet ejection device of the present invention, a plurality of nozzles are two-dimensionally arranged on the droplet ejection surface, and a second region having a ring shape surrounding the nozzles is formed for each of the nozzles. The second regions to be connected may be connected by a connecting portion having higher liquid repellency than the first region. At this time, the plurality of connecting portions may connect the plurality of second regions surrounding the plurality of nozzles arranged along one direction forming the nozzle row on the droplet discharge surface. Alternatively, the plurality of connecting portions are arranged along the direction intersecting the plurality of second regions surrounding the plurality of nozzles arranged along the one direction forming the nozzle row on the droplet discharge surface, and the one direction. A plurality of second regions surrounding the plurality of nozzles arranged in a row may be connected to each other. According to this, it is possible to form a region where a droplet is unlikely to exist between the second regions surrounding the nozzle by the connecting portion.

  In the liquid droplet ejecting apparatus of the present invention, the first force necessary for the liquid droplets to enter the connecting portion from the first region on the one side of the nozzle row is such that the liquid droplets are on the other side of the nozzle row. It may be smaller than the second force required to enter the connecting portion from the first region. According to this, the directionality of the movement can be given to the droplet that has moved away from the nozzle by the connecting portion.

  At this time, the droplets enter the connecting portion from the first region farther from the nozzle row of the two outermost nozzle rows between the two first regions sandwiching each nozzle row. The required first force is a droplet from the first region closer to the nozzle row of the two outermost nozzle rows of the two first regions sandwiching each nozzle row to the connecting portion. May be less than the second force required to enter. According to this, it becomes easy to move a droplet outside by a connection part.

  At this time, the boundary between the first region closer to the far side from the nozzle row of the two outermost nozzle rows among the two first regions sandwiching each nozzle row is defined by a zigzag line. May be. When the liquid droplet moves in the direction away from the nozzle, the rising angle of the liquid droplet easily reaches the limit angle when the liquid droplet enters the connecting portion from the first region, so that the liquid droplet can be easily moved outward.

(First embodiment)
Hereinafter, a preferred first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view depicting the internal configuration of a color inkjet printer according to the present embodiment. In FIG. 1, a head unit 63 is disposed in the color inkjet printer 1. Four piezoelectric inkjet heads 6a, 6b, 6c, and 6d that discharge yellow, magenta, cyan, and black inks are fixed to the main body frame 68 of the head unit 63, respectively. Further, a total of four ink cartridges 61 each filled with color ink are detachably attached to the main body frame 68. The main body frame 68 is fixed to a carriage 64 that is reciprocally driven in a linear direction by a driving mechanism (reciprocating means) 65. A platen roller 66 as a conveying means for conveying the paper 62 as a recording medium is arranged so that its axis is along the reciprocating direction of the carriage 64, and faces the inkjet heads 6 a to 6 d.

  The carriage 64 is slidably supported by a guide shaft 71 and a guide plate 72 that are disposed in parallel with the support shaft of the platen roller 66. Pulleys 73 and 74 are supported in the vicinity of both ends of the guide shaft 71, and an endless belt 75 is bridged between the pulleys 73 and 74. The carriage 64 is fixed at an appropriate position of the endless belt 75.

  In such a configuration of the drive mechanism 65, when one pulley 73 rotates forward and backward by driving the motor 76, the carriage 64 reciprocates in a linear direction along the guide shaft 71 and the guide plate 72. The head unit 63 also reciprocates.

  The paper 62 is fed from a paper feed cassette (not shown) provided on the side of the ink jet printer 1 and guided to the space between the ink jet heads 6a to 6d and the platen roller 66, and the ink jet heads 6a to 6a. The paper is discharged after being printed with the ink discharged from 6d. In FIG. 1, the paper feed mechanism and paper discharge mechanism for the paper 62 are not shown.

  Further, a purge mechanism 67 shown at the lower left in FIG. 1 is provided in the ink jet printer 1. The purge mechanism 67 is for forcibly sucking and removing defective ink containing bubbles, dust and the like accumulated in the ink jet heads 6a to 6d. The purge mechanism 67 is provided on the side of the platen roller 66. The position of the purge mechanism 67 is determined so as to sequentially face one of the four inkjet heads 6a to 6d when the head unit 63 reaches the reset position by the drive mechanism 65. The purge mechanism 67 is provided with a purge cap 81, which contacts the lower surface of any one of the inkjet heads 6a to 6d so as to cover a large number of nozzles 109 (see FIG. 2) provided on the lower surface of each inkjet head 6a to 6d. Touch.

  With this configuration, when the head unit 63 is at the reset position, any one of the nozzles 109 of the ink jet heads 6a to 6d is covered with the purge cap 81, and air bubbles accumulated inside the ink jet heads 6a to 6d are included. The defective ink is sucked by the pump 82 by the drive of the cam 83 and discarded in the waste ink reservoir 84, whereby the inkjet heads 6a to 6d are restored. Such an operation is sequentially performed on the four inkjet heads 6a to 6d. Thereby, bubbles can be removed when ink is initially introduced into the ink jet heads 6a to 6d, and the ink jet heads 6a to 6d are returned to a normal state from a discharge failure state caused by growth of internal bubbles accompanying printing. be able to. Note that the four caps 85 shown in FIG. 1 cover a large number of nozzles 109 of the corresponding inkjet heads 6a to 6d on the carriage 64 that has been printed and returned to the reset position to prevent ink drying. Is.

  FIG. 2 shows a perspective view of the head unit 63 turned upside down. As shown in FIG. 2, the main body frame 68 of the head unit 63 is formed in a substantially box shape with its upper surface side (drawn so as to face downward in FIG. 2) being opened. A mounting portion is formed so that the four ink cartridges 61 can be detachably mounted from the rear side.

  The lower surface of the bottom plate 5 of the main body frame 68 (surface on the side to which the ink jet heads 6a to 6d are fixed: drawn to face upward) in FIG. The four ink supply passages 51 that are connected to the ink discharge portions of the ink cartridges 61 are provided. A rubber-made joint member 47 is attached to the bottom surface of the bottom plate 5 so as to be in close contact with the ink supply ports (not shown) of the inkjet heads 6a to 6d so as to correspond to the ink supply passages 51. .

  As shown in FIG. 2, on the lower surface side of the bottom plate 5, four support portions 8 for arranging the four inkjet heads 6 a to 6 d in parallel are formed as stepped concave portions. In each support portion 8, a plurality of cavities 9a and 9b for fixing the corresponding inkjet heads 6a to 6d with a UV adhesive material are formed so as to penetrate vertically.

  FIG. 3 shows a partial cross-sectional view of the inkjet head 6a. Since the four inkjet heads 6a to 6d have the same configuration, only one inkjet head 6a will be described. As shown in FIG. 3, the inkjet head 6a includes an actuator unit 106 driven by a drive signal from a control unit (not shown) and a flow path unit 107 that forms an ink flow path. The actuator unit 106 and the flow path unit 107 are bonded together by an epoxy thermosetting adhesive. Further, although the FPC 40 is joined to the upper surface of the actuator unit 106, the FPC 40 is not drawn in FIG. 3 in order to simplify the drawing.

  The flow path unit 107 is composed of three thin plates (cavity plate 107a, spacer plate 107b, manifold plate 107c) made of a metal material and a polyimide having a nozzle 109 for discharging ink. It is configured by laminating a resin nozzle plate 107d. The uppermost cavity plate 107 a is in contact with the actuator unit 106.

  On the surface of the cavity plate 107a, a plurality of pressure chambers 110 for storing ink selectively ejected by the operation of the actuator unit 106 are formed in two rows along the longitudinal direction. The plurality of pressure chambers 110 are separated from each other by a partition wall 110a, and are arranged with their longitudinal directions aligned in parallel. The spacer plate 107b is formed with a communication hole 111 for communicating one end of the pressure chamber 110 with the nozzle 109 and a communication hole (not shown) for communicating the other end of the pressure chamber 110 with a manifold channel (not shown). Has been.

  The manifold plate 107 c is formed with a communication hole 113 that allows one end of the pressure chamber 110 to communicate with the nozzle 109. Further, a manifold channel for supplying ink to each pressure chamber 110 is formed in the manifold plate 107 c so as to be long in the column direction below the column formed by the plurality of pressure chambers 110. One end of the manifold channel is connected to the ink cartridge 61 via the ink supply passage 51 shown in FIG. As shown in FIG. 2, the nozzle plate 107d is formed with a plurality of nozzles 109 arranged in two rows in a staggered manner along the extending direction of the nozzle plate 107d. Further, as shown in FIG. 3, a water repellent layer 130 made of a fluorine-based resin is formed on the lower surface (ink ejection surface) 129 of the nozzle plate 107d. Each of such plates 107a to 107d is aligned so as to form an individual ink flow path 103 extending from the manifold flow path to the nozzle 109 through a communication hole (not shown), a pressure chamber 110, a communication hole 111, and a communication hole 113. By laminating, a flow path unit 107 having a rectangular planar shape extending in a direction orthogonal to the reciprocating direction of the head unit 63 (a direction parallel to the paper transport direction) is configured.

  In the actuator unit 106, two piezoelectric ceramic plates 106a and 106b made of a ceramic material of lead zirconate titanate (PZT) are laminated. On the upper surface of the piezoelectric ceramic plate 106 a, the individual electrode 121 is disposed at a position that overlaps the range corresponding to the pressure chamber 110 of the flow path unit 107. A common electrode 122 is disposed between the piezoelectric ceramic plate 106 a and the piezoelectric ceramic plate 106 b so as to straddle all the pressure chambers 110 of the flow path unit 107.

  The common electrode 122 is always held at the ground potential. On the other hand, the individual electrode 121 is given a drive signal. The sandwiched region of the piezoelectric ceramic plate 106a sandwiched between the common electrode 122 and the individual electrode 121 becomes an active portion 123 that is polarized in the stacking direction when an electric field is applied beforehand by these electrodes. Therefore, when the potential of the individual electrode 121 becomes a predetermined positive potential, the active portion 123 of the piezoelectric ceramic plate 106a is applied with an electric field and tends to extend in the stacking direction. However, since the lower surface of the piezoelectric ceramic plate 106b is fixed to the upper surface of the partition wall 110a that partitions the pressure chamber 110, the piezoelectric ceramic plates 106a and 106b are deformed so as to protrude toward the pressure chamber 110 as a result. . For this reason, the volume of the pressure chamber 110 is decreased, the ink pressure is increased, and ink is ejected from the nozzle 109.

  Next, the ink ejection surface 129 of the nozzle plate 107d will be described below. FIG. 4 is an enlarged plan view of the ink ejection surface 129 of the nozzle plate 107d shown in FIG. As shown in FIG. 4, a water repellent layer 130 and an ink absorber 125 made of a material such as a sponge capable of absorbing ink are formed on the ink ejection surface 129 of the nozzle plate 107d. The ink absorber 125 extends in parallel along the direction in which the ink discharge surface 129 extends (the vertical direction in FIG. 4), and is disposed at both ends of the ink discharge surface 129 on the left and right sides in FIG. .

  The four water-repellent layers 130 are arranged on the left and right sides of the first water-repellent layer (third region) 141 formed in the vicinity of the nozzle 8 and on the left and right sides of the first water-repellent layer 141, and the ink discharge surface 129 extends. It consists of eight second water repellent layers (second regions) 142 extending in parallel to the direction. The first water repellent layer 141 and the second water repellent layer 142 have the same water repellency. The first water-repellent layer 141 extends in the direction of two rows of nozzles formed by the plurality of nozzles 109, and a plurality of nozzles 8 arranged in two rows in a staggered manner exist inside the first water-repellent layer 141. . That is, the first water repellent layer 141 is formed so as to cover all of the periphery of the plurality of nozzles 8. The eight second water repellent layers 142 are arranged apart from each other in the direction orthogonal to the extending direction of the ink ejection surface 129. On the ink ejection surface 129, a plurality of regions where the water repellent layer 130 is not formed, that is, hydrophilic regions (first regions) 128a to 128e are formed. The hydrophilic region 128a exists between the first water repellent layer 141 and the second water repellent layer 142, the hydrophilic regions 128b to 128d exist between the second water repellent layer 142, and the hydrophilic region 128e is , Present between the water repellent layer 142 and the ink absorber 125. That is, on the ink ejection surface 129, the first water repellent layer 141, the hydrophilic region 128 a, the second water repellent layer 142, the hydrophilic region 128 b, and the second water repellent layer 142 are directed from the nozzle 109 toward the ink absorber 125. The second water repellent layer 142 and the hydrophilic regions 128a to 128e are alternately arranged in the order as described above.

  As shown in FIG. 4, the left and right ends of the first water repellent layer 141 are straight lines in which the boundary line 151 between the first water repellent layer 141 and the hydrophilic region 128 a is parallel to the extending direction of the ink ejection surface 129. It is formed to become. The end 142a of the second water repellent layer 142 on the first water repellent layer 141 side has a flow path unit 107 so that the boundary line 152 between the second water repellent layer 142 and the hydrophilic regions 128a to 128d has a zigzag shape. A plurality of inclined portions 143 that are symmetrically inclined with respect to the extending direction are formed along the extending direction of the ink discharge surface 129. These inclined portions 143 are formed by cutting out part of the end 142a of the second water repellent layer 142 by laser processing. On the other hand, at the end 142b of the second water repellent layer 142 on the ink absorber 125 side, the boundary line 153 between the second water repellent layer 142 and the hydrophilic regions 128b to 128e is parallel to the extending direction of the flow path unit 107. It is formed to be a straight line.

  Next, the movement of the ink droplets adhering to the ink ejection surface 129 accompanying the reciprocating movement of the head unit 63 will be described below. FIG. 5 is an enlarged view of the ink ejection surface shown in FIG. 4, (a) is a diagram showing a situation where ink droplets are attached to the ink ejection surface 129, and (b) is a one-way movement of the head unit 63. FIG. 7 is a diagram showing a state before ink droplets pass on the second water repellent layer 142 in accordance with (moving in the right direction in the figure), and FIG. FIG. 6D is a diagram illustrating a situation after the droplet has passed over the second water-repellent layer 142, and FIG. 4D is a diagram illustrating a case where the ink droplet is second when the head unit 63 moves in the other direction (moving leftward in the drawing). It is a figure which shows the condition after passing on a water repellent layer, (e) is a figure which shows the condition where the ink droplet moved on the ink absorber 125.

  When printing on the paper 62, ink droplets are ejected from the nozzles 109 while the head unit 63 reciprocates by the drive mechanism 65. At this time, for example, as shown in FIG. 5A, the first water repellent layer 141 and the second water repellent layer 142 are caused on the ink ejection surface 129 by rebound of ink droplets from the paper 62, ink mist, or the like. It is assumed that two ink droplets 161 and 162 are attached on the hydrophilic region 128a between the two. When printing is continued on the paper 62 with the two ink droplets 161 and 162 attached to the ink ejection surface 129, as shown in FIG. 5B, the head unit 63 moves to the right side in the figure. The two adhered ink droplets 161 and 162 are moved to the left in the figure on the ink ejection surface 129 by receiving a force such as inertia force or air, and the ink droplet 161 and the second water repellent layer 142 and the ink droplet 162 are moved. Is in contact with the first water repellent layer 141. At this time, the ink droplet 162 in contact with the first water repellent layer 141 stops on the boundary line 151. This is because the ink droplet 162 is repelled by the water repellent layer 141 in the same direction as the movement direction of the head unit 63 and the boundary line 151 is a straight line, so that the ink ejection surface 129 of the ink droplet 162 on the boundary line 151 is. This is because the rising angle from the same angle is the same at any position and does not exceed the limit angle (that is, the angle at which the ink meniscus of the ink droplet breaks and the ink droplet can move onto the water repellent layer).

  Here, the force for the ink droplet 162 to move on the ink ejection surface 129 is related to the reciprocating speed and acceleration of the head unit 63 (that is, if the reciprocating speed and acceleration of the head unit 63 are high, (If the wind force and inertial force received by the ink droplet are increased and the reciprocating speed and acceleration of the head unit 63 are reduced, the wind force and inertial force received by the ink droplet are reduced). In the present embodiment, the reciprocating speed and acceleration of the head unit 63 are adjusted so that the rising angle of the ink droplet 162 from the ink ejection surface 129 does not exceed the limit angle on the boundary line 151. Has been. Therefore, the ink droplet 162 stops moving on the boundary line 151 and does not transfer onto the first water repellent layer 141.

  On the other hand, the ink droplet 161 in contact with the second water repellent layer 142 tries to get over the boundary line 152. This is because the end angle 142a of the second water repellent layer 142 is formed in a zigzag shape, so that the limit angle of the ink droplet 161 on the boundary line 152 becomes larger than the limit angle on the boundary line 151 described above. This is because there are a mixture of places and smaller places. That is, in the present embodiment, the second water repellent is applied to the ink droplet 161 as a leftward force that tries to move to the second water repellent layer 142 after the ink droplet 161 reaches the boundary line 152 is applied. This is because the rising angle of the ink meniscus of the ink droplet 161 becomes larger than the other portions at the tip portion near the nozzle 109 side in the end portion 142a of the layer 142, and reaches the limit angle and is cheap. In addition, the boundary line 153 is formed so that the distance between the end portions close to the nozzle 109 side of the end portion 142a of the second water repellent layer 142 in the present embodiment is about 5 to 10 μm. As a result, if the ink droplets 161 and 162 have an ink droplet diameter of at least 5 μm or more, as described above, the ink droplets 161 and 162 come into contact with at least one tip portion of the end portion 142a on the boundary line 152. Then, it reaches the limit angle and moves onto the second water repellent layer 142. If the diameter of the ink droplet is less than 5 μm and moves on the ink ejection surface 129 as the head unit 63 reciprocates, the ink droplet is contained between the tip portions of the end portion 142a, and the ink droplet 161 , 162 is less likely to reach the limit angle. However, if the diameter of the ink droplets 161 and 162 is less than 5 μm, the head unit 63 hardly moves due to the reciprocating movement, and the ink droplet does not drop on the paper side due to its own weight. That is, if the diameter of the ink droplet is less than 5 μm, the ink droplet has almost no adverse effect.

  Further, the force (first force) for moving the ink droplets over the boundary line 152 and on the second water-repellent layer 142 moves over the boundary line 151 and the ink droplets move on the first water-repellent layer 141. The ink droplet 161 can be stopped on the boundary line 152 without overcoming the boundary line 152 for the first time by becoming a force smaller than the force (second force).

  However, the reciprocating speed and acceleration of the head unit 63 in this embodiment are the same moving speed and acceleration in one direction and the other direction reversed, and each force received by the ink droplets 161 and 162 is the head unit. Since the force is an inertial force or air force generated by the reciprocating movement 63, the forces are almost the same. Further, the reciprocating speed and acceleration of the head unit 63 are adjusted as described above, but the ink droplet 161 on the boundary line 152 exceeds the limit angle at the tip end portion of the end portion 142 a of the second water repellent layer 142. Further, the reciprocating speed and acceleration of the head unit 63 are adjusted. Accordingly, since the ink droplets 161 and 162 are subjected to substantially the same force to move on the ink ejection surface 129, the ink of the ink droplet 161 is formed on the boundary line 152 and at the tip of the end 142a on the nozzle 109 side. Only the meniscus breaks and moves over the second water repellent layer 142 to the hydrophilic region 128b as shown in FIG.

  Then, as shown in FIG. 5D, when the head unit 63 moves to the left side, the two ink droplets 161 and 162 attached to it receive a force such as an inertial force or air to the right on the ink ejection surface 129. The ink droplet 161 stops contacting the second water repellent layer 142 on the boundary line 153, and the ink droplet 162 moves on the second water repellent layer 142 to enter the hydrophilic region 128b. Moving. The ink droplet 161 is repelled by the second water repellent layer 142 in the same direction as the moving direction of the head unit 63 and the boundary line 153 is a straight line, so the ink ejection surface of the ink droplet 161 on the boundary line 153 Since the rising angle from 129 becomes the same angle at any position and does not exceed the limit angle, the movement is stopped on the boundary line 153. On the other hand, since the end 142a of the second water repellent layer 142 is formed in a zigzag shape, the ink droplet 162 is transferred to the second water repellent layer 142 after the ink droplet 162 reaches the boundary line 152. As the rightward force to be applied is applied to the ink droplet 162, the rising angle of the ink meniscus of the ink droplet 162 is higher than that of the other portion at the tip portion near the nozzle 109 side of the end portion 142a of the second water repellent layer 142. Increases to reach the limit angle. As a result, only the ink meniscus of the ink droplet 162 breaks and moves over the second water repellent layer 142 to the hydrophilic region 128b as shown in FIG.

  Then, as shown in FIG. 5E, the head unit 63 repeatedly moves in the left-right direction along with printing, so that the two ink droplets 161, 162 attached to the ink ejection surface 129 gradually move away from the nozzle 109, It moves onto the ink absorber 125 disposed at both ends of the ink discharge surface 129 in the short direction. The two ink droplets 161 and 162 that have moved onto the ink absorber 125 are absorbed by the ink absorber 125. In this way, it is possible to prevent the ink droplets 161 and 162 from dropping from the ink ejection surface 129.

  In the second water repellent layer 142 formed on the ink ejection surface 129 in this way, a zigzag boundary line 152 is formed at the end 142 a near the nozzle 109, and flows to the end 142 b far from the nozzle 109. Since the straight boundary line 153 parallel to the extending direction of the path unit 107 is formed, the attached ink droplets 161 and 162 move only in the direction away from the nozzle 109 when the head unit 63 reciprocates. The first water repellent layer 141 is formed so as to cover the entire periphery of the nozzle 109, and the boundary line 151 between the first water repellent layer 141 and the hydrophilic region 128 a adjacent to the first water repellent layer 141 extends the channel unit 107. Since it is a straight line parallel to the current direction, the ink droplets 161 and 162 do not enter the nozzle 109. In the above-described embodiment, the boundary lines 151 and 153 are straight lines along the extending direction of the flow path unit 107, and the zigzag where the boundary line 152 extends along the extending direction of the flow path unit 107. Although it is a shape line, these boundary lines 151 to 153 may all be zigzag lines. In this case, the sandwiching angle between the boundary lines 151 and 153 (the angle formed by two symmetrically inclined straight lines constituting the zigzag line) must be formed to be larger than the sandwiching angle of the boundary line 152.

  In the second water repellent layer 142 in the present embodiment, the end 142a on the side close to the nozzle 109 has a zigzag shape, so that the ink droplets 161 and 162 can easily move only in the direction away from the nozzle 109. However, the second water repellent layers 182, 192, and 198 according to the first to third modifications as shown in FIGS. 6 to 8 may be formed. FIG. 6 is a view showing a first modification of the second water repellent layer formed on the ink ejection surface of the head unit according to the first embodiment of the present invention. FIG. 7 is a view showing a second modification of the second water repellent layer formed on the ink ejection surface of the head unit according to the first embodiment of the present invention. FIG. 8 is a view showing a third modification of the second water repellent layer formed on the ink ejection surface of the head unit according to the first embodiment of the present invention.

  As shown in FIG. 6, the second water repellent layer 182 in the first modified example is stepwise in a direction away from the nozzle 109 from the end on the first water repellent layer 141 side (left and right direction in FIG. 6). First to third water-repellent regions 183a to 183c having improved water repellency are formed. The first water repellent region 183a is formed in the second water repellent layer 182 on the side closest to the nozzle 109, and has a water repellency with respect to ink droplets as compared with the second and third water repellent regions 183b and 183c. It is getting smaller. The second water-repellent region 183b is formed between the first and third water-repellent regions 183a and 183c in the second water-repellent layer 182 and has a water repellency with respect to ink droplets compared to the third water-repellent region 183c. And getting smaller. The third water repellent region 183c is formed on the side farthest from the nozzle 109 in the second water repellent layer 182, and the water repellency with respect to the ink droplet is compared with the first and second water repellent regions 183a and 183b. And has the same water repellency as the first water repellent layer 141.

  With this configuration, ink droplets on the boundary line 171 between the first water-repellent region 183a and the hydrophilic regions 128a to 128d of the second water-repellent layer 182 are hydrophilic to the third water-repellent region 183c of the second water-repellent layer 182. The ink drops reach the limit angle and become cheaper than ink drops on the boundary line 172 with the hydrophilic regions 128b to 128e and ink drops on the boundary line 173 between the first water repellent layer 141 and the hydrophilic region 128a. In other words, since the water repellency of the first water repellent area 183a is smaller than that of the second water repellent area 183b, the third water repellent area 183c, and the first water repellent layer 141, the upper limit value of the ink droplet limit angle on the boundary line 171 Becomes smaller than on the other boundary lines 172 and 173. Therefore, ink droplets that have received the same force due to the reciprocation of the head unit 63 exceed the boundary line 171 from the hydrophilic regions 128a to 128d, but do not exceed the boundary lines 172 and 173 from the hydrophilic regions 128a to 128e. As described above, the second water repellent layer 182 in the first modified example can also move ink droplets away from the nozzle 109 by the reciprocating movement of the head unit 63, similarly to the second water repellent layer 142 described above.

  As shown in FIG. 7, a plurality of circular hydrophilic regions 193 are formed in the second water repellent layer 192 in the second modification. These hydrophilic regions 193 are formed in the second water repellent layer 192 in the direction away from the nozzle 109 from the end on the first water repellent layer 141 side (left and right direction in FIG. 7). Is formed to decrease. That is, the average density of the plurality of hydrophilic regions 193 of the second water repellent layer 192 decreases as the distance from the side closer to the first water repellent layer 141 increases. Further, a hydrophilic region row 194 in which a plurality of hydrophilic regions 193 are arranged along the extending direction of the second water repellent layer 192 at the end of the second water repellent layer 192 on the first water repellent layer 141 side. Is formed. The hydrophilic region row 194 is formed at a position very close to the boundary line 185 between the second water repellent layer 192 and the hydrophilic region 128a.

  With this configuration, ink droplets on the boundary line 185 between the second water repellent layer 192 and the hydrophilic regions 128a to 128d are ink droplets on the boundary line 186 between the second water repellent layer 192 and the hydrophilic regions 128b to 128e. In addition, the boundary line 185 is more easily exceeded than the ink droplet on the boundary line 187 between the first water repellent layer 141 and the hydrophilic region 128a. That is, the hydrophilic region row 194 formed by the plurality of hydrophilic regions 193 is formed at the end of the second water repellent layer 192 on the side close to the first water repellent layer 141, so that the hydrophilic regions 128a to 128d are formed. When the existing ink droplet moves to the boundary line 185 and reaches the boundary line 185, the hydrophilic region 193 belonging to the hydrophilic region row 194 comes into contact with the ink droplet, and the hydrophilic region 193 causes the ink droplet to pass through the second water repellent. Try to pull onto layer 192. Thus, the ink droplet on the boundary line 185 reaches a limit angle and becomes cheaper than the other boundary lines 186 and 187, and the ink droplet moves on the second water repellent layer 192 in a direction away from the nozzle 109. The ink droplets on the boundary lines 186 and 187 cannot move on the second water repellent layer 192 and the first water repellent layer 141 because the hydrophilic region 193 does not exist in the vicinity thereof. As described above, the second water repellent layer 192 in the second modified example can also move the ink droplets away from the nozzle 109 by the reciprocating movement of the head unit 63 in the same manner as the second water repellent layer 142 described above. In the present modification, the hydrophilic region 193 is formed in the vicinity of the boundary line 185, but may be arranged so that the center thereof is positioned on the boundary line 185. As a result, the boundary line 185 has a semicircular portion of the hydrophilic region 193, and thus has substantially the same function as the zigzag shape of the boundary line 152 described above, and the ink is formed on the second water repellent layer 192. Drops can be easily moved.

  As shown in FIG. 8, the second water repellent layer 198 in the third modified example has a low water repellent part 199a having a lower water repellency than the first water repellent layer 141, and a higher water repellency than the low water repellent part 199a. The first water-repellent layer 141 includes a plurality of circular highly water-repellent portions 199 b having the same water repellency. These highly water-repellent portions 199b are formed in the second water-repellent layer 198 from the outer end away from the first water-repellent layer 141 toward the nozzle 109 (the left-right direction in FIG. 8). It is formed so that the number of formation of 199b decreases. That is, the average density of the highly water-repellent portion 199b of the second water-repellent layer 198 increases as the distance from the first water-repellent layer 141 side increases. A plurality of highly water-repellent portions 199 b are arranged along the extending direction of the second water-repellent layer 198 at the outer end portion of the second water-repellent layer 198 away from the first water-repellent layer 141. A partial row 200 is formed. The water repellent part row 200 is formed at a position very close to the boundary line 196 between the second water repellent layer 198 and the hydrophilic regions 128b to 128e.

  With this configuration, the ink droplet on the boundary line 195 between the second water repellent layer 198 and the hydrophilic regions 128a to 128d is the ink droplet on the boundary line 186 between the second water repellent layer 198 and the hydrophilic regions 128b to 128e. In addition, the boundary line 195 is more easily exceeded than the ink droplet on the boundary line 197 between the first water repellent layer 141 and the hydrophilic region 128a. That is, since the high water-repellent portion 199b is not formed at the end portion of the second water-repellent layer 198 closer to the first water-repellent layer 141, the boundary lines 196 and 197 than the ink droplets on the boundary line 195. The upper limit value of the limit angle of ink droplets is larger for the ink droplets. Therefore, the ink droplet on the boundary line 195 reaches the limit angle and becomes cheaper than the other boundary lines 196 and 197, and the ink droplet moves on the second water repellent layer 198 in a direction away from the nozzle 109. The ink droplet on the boundary line 196 cannot move onto the second water repellent layer 198 by the high water repellent portion 199b formed in the vicinity thereof. As described above, the second water repellent layer 198 in the third modified example can also move ink droplets away from the nozzle 109 by the reciprocating movement of the head unit 63 in the same manner as the second water repellent layer 142 described above.

  According to the ink jet heads 6a to 6d of the ink jet printer 1 in the present embodiment as described above, the ink droplets 161 and 162 attached to the ink ejection surface 129 cause the inertial force and the force from the air received by the reciprocating movement of the head unit 63. For example, the nozzle 109 can be moved away. Therefore, the ink droplets 161 and 162 adhering to the ink ejection surface 129 are absorbed by the ink absorber 125, so that the ink droplets 161 and 162 can be removed from the ink ejection surface 129. As a result, it is not necessary to wipe the ink ejection surface 129 frequently, and the frequency of wiping can be reduced. Therefore, the ink ejection surface can have a long life, and when used in a serial printer, the printing speed can be increased.

  In addition, since the second water repellent layer 142 and the hydrophilic regions 128a to 128e formed on the ink ejection surface 129 are alternately formed, the ink is temporarily formed in the hydrophilic regions 128b to 128d between the second water repellent layers 142. Drops 161 and 162 can be held. Therefore, even if the reciprocating direction of the head unit 63 is reversed from one direction and changed to the other direction, the ink droplets 161 and 162 are likely to gradually move away from the nozzle 109. In addition, since the first water-repellent layer 141 is formed on the ink ejection surface 129, it is difficult for ink droplets to adhere to the periphery of the nozzle 109.

  Further, the ink droplet 161 on the boundary line 152 is applied so that the reciprocating speed and acceleration of the head unit 63 is applied to the ink droplets 161 and 162 on the boundary lines 151 and 153 so as not to exceed the limit angle. , 162 is adjusted so that a force exceeding the limit angle is applied to the tip of the end 142 a of the second water repellent layer 142, so that the ink droplets 161, 162 are forced to the ink absorber 125. It is not necessary to provide the ink jet printer 1 with a special configuration that gives a force for moving. Thereby, the manufacturing cost of the inkjet printer 1 does not increase.

(Second Embodiment)
Next, an ink jet head according to a second embodiment will be described below with reference to FIG. FIG. 9 is an explanatory diagram showing the ink ejection surface 229 of the inkjet head 206 according to the second embodiment of the present invention. In addition, about the thing similar to 1st Embodiment mentioned above, it shows with the same code | symbol and abbreviate | omits description.

  As shown in FIG. 9, the inkjet head 206 according to the present embodiment has a nozzle row 209 in which a plurality of nozzles 109 are arranged in four rows along the extending direction of the ink discharge surface 229 on the ink discharge surface 229. doing. The four nozzle rows 209 are spaced apart from each other by two rows on the right and left sides of the ink discharge surface 229 in FIG. 9, and the two nozzle rows 209 on each side separate the nozzle row group 210a, 210b is configured. The plurality of nozzles 109 belonging to each of the nozzle groups 210a and 210b are arranged in a staggered manner along the extending direction of the ink discharge surface 229.

  On the ink ejection surface 229, the first water repellent layer 141, the second water repellent layer 142, the third water repellent layer (fifth region) 243, and the fourth water repellent layer (fifth region) 244 are formed. A water layer 230 is formed. On the ink ejection surface 229, a plurality of regions where the water-repellent layer 230 is not formed, that is, hydrophilic regions 228 are formed. In addition, an ink absorber 225 similar to the ink absorber 125 described above is formed on the ink discharge surface 229 so as to surround the water-repellent layer 230 on the outer periphery thereof.

  Two first water repellent layers 141 are formed so as to sandwich the third and fourth water repellent layers 243 and 244 from the left and right sides in FIG. 9. The first water repellent layer 141 is formed for each of the nozzle groups 210a and 210b so as to cover the vicinity of the outer periphery of the plurality of nozzles 109. The second water repellent layers 142 are formed along the extending direction of the ink discharge surface 229, and are formed in eight rows so as to be separated from each other in a direction orthogonal to the extending direction of the ink discharge surface 229. These second water repellent layers 142 are arranged in two rows on the left and right sides in FIG. 9 with respect to one first water repellent layer 141. The first to fourth water repellent layers 141, 142, 243, and 244 are made of a fluorine-based resin as described above.

  The third water-repellent layer 243 and the fourth water-repellent layer 244 have the same configuration as the second water-repellent layer 142, and the length in the extending direction is shortened, and the direction is perpendicular to the extending direction of the ink ejection surface 229 It is arranged by being rotated by 90 ° so that the extending directions thereof are parallel to each other, and a plurality of them are arranged apart from each other in parallel to the extending direction of the ink discharge surface 229. As a result, hydrophilic regions (fourth regions) 228 extending in the same direction as the third and fourth water repellent layers 243 and 244 are formed on the ink ejection surface 229 with the ink absorber 225 and the third water repellent layer 243. , Between the third water repellent layer 243, between the third and fourth water repellent layers 243 and 244, between the fourth water repellent layer 244 and between the ink absorber 225 and the fourth water repellent layer 244. ing. The plurality of third water repellent layers 243 are arranged in the upper part of FIG. 9 with a center line 203 orthogonal to the extending direction on the ink ejection surface 229 as a boundary, and the third water repellent layer 243, the hydrophilic region 228, and the like. Are alternately arranged along the extending direction of the ink discharge surface 229. The plurality of fourth water repellent layers 244 are arranged in the lower part of FIG. 9 with the center line 203 as a boundary, and the fourth water repellent layers 244 and the hydrophilic regions 228 are alternately arranged along the extending direction of the ink ejection surface 229. Is arranged. Each third water repellent layer 243 is disposed on the lower side in FIG. 9 such that the boundary line 251 between the third water repellent layer 243 and the hydrophilic region 228 has a zigzag shape. Each fourth water-repellent layer 244 is arranged on the upper side in FIG. 9 such that the boundary line 252 between the fourth water-repellent layer 244 and the hydrophilic region 228 has a zigzag shape. Note that the second water repellent layer 142 is disposed on the side closer to the nozzle 109 where the boundary line 253 between the second water repellent layer 142 and the hydrophilic region 228 has a zigzag shape, as described above.

  Airflow direction plates 261 and 262 are respectively provided on the side walls of the inkjet head 206 corresponding to the upper and lower portions in FIG. 9, and the airflow direction plates 261 and 262 are inclined so as to approach the provided side walls. Both of these wind direction plates 261 and 262 slightly protrude from the ink discharge surface 229 in the direction perpendicular to the paper surface in FIG. 9 (ink discharge direction from the nozzle 109), and are point-symmetric with respect to the center point 204 of the ink discharge surface 229. It is arranged to be. Such wind direction plates 261 and 262 are moved from the upper side in FIG. 9 within the ink discharge surface 229 when the inkjet head 206 is reciprocated in the direction of arrow A in FIG. A downward air flow B is created, and the wind direction plate 262 creates an upward air flow C from the lower side in FIG. As a result, air flow D and air flows B and C in the left-right direction in FIG. 9 (reciprocal movement direction of the head unit) created by the reciprocation of the head unit exist in the ink ejection surface 229. Become. (In actuality, there is a flow in which these flows are mixed.) The air flow B passes through a region in which the fourth water repellent layer 244 is formed mainly from above in FIG. The air flow C is directed downward from the lower side in FIG. 9 mainly through the region where the third water repellent layer 243 is formed, by the wind direction plate 262.

  When such an inkjet head 206 performs printing on a sheet, the nozzle 109 ejects ink droplets while reciprocating by the drive mechanism 65 as in the first embodiment. At this time, for example, as shown in FIG. 9, hydrophilicity between the first water-repellent layer 141 and the second water-repellent layer is caused on the ink ejection surface 229 by rebound of ink droplets from the paper or ink mist. Four ink droplets 271 to 274 adhere on the sex region 228. Of the four ink droplets 271 to 274 that have adhered, the ink droplets 272 and 273 that have adhered to the outside of the first water repellent layer 141 within the ink ejection surface 229 are outside due to the air flow D caused by the reciprocating movement of the inkjet head 206. And is absorbed by the ink absorber 225. This is because, in the second water repellent layer 142 formed outside the ink droplets 272 and 273, the boundary line 253 on the nozzle 109 side of the second water repellent layer 142 and the hydrophilic region 228 has a zigzag shape. Therefore, the limit angle is easily reached only when the ink droplets 272 and 273 exceed the boundary line 253. Therefore, in the same manner as described above, the ink droplets 272 and 273 extend beyond the second water repellent layer 142 toward the outside from the hydrophilic region 228 between the first water repellent layer 141 and the second water repellent layer 142. It moves to the absorber 225. In this way, the ink droplets 272 and 273 are absorbed by the ink absorber 225.

  On the other hand, a plurality of third water repellent layers 243 are formed on the ink droplets 271 attached inside the first water repellent layer 141 in the ink ejection surface 229 due to the air flow D due to the reciprocating movement of the inkjet head 206. It moves toward the center of the region above the center line 203 on the ink ejection surface 229, and moves upward from the hydrophilic region 228 between the third water repellent layers 243 by the air flow C in FIG. Absorbed by the ink absorber 225. This is because, in the second water repellent layer 142 formed inside the first water repellent layer 141, the boundary line 253 with the hydrophilic region 228 on the nozzle 109 side of the second water repellent layer 142 has a zigzag shape. 9 and the boundary line 251 between the lower end of the third water repellent layer 243 in FIG. 9 and the hydrophilic region 228 has a zigzag shape, whereby the ink droplet 271 has boundary lines 251 and 253. It is easy to reach the limit angle only when exceeding. Therefore, the ink droplets 271 pass from the hydrophilic region 228 between the first water repellent layer 141 and the second water repellent layer 142 inward and beyond the second water repellent layer 142 to between the third water repellent layers 243. It reaches the hydrophilic region 228 and moves from there to the ink absorber 225 over the third water repellent layer 243. In this way, the ink droplet 271 is absorbed by the ink absorber 225.

  Further, the ink droplet 274 is a region below the center line 203 on the ink discharge surface 229 on which the plurality of fourth water repellent layers 244 are formed by the air flow D along the reciprocating direction due to the reciprocating movement of the inkjet head 206. 9, and moves toward the lower side in FIG. 9 from the hydrophilic region 228 between the fourth water repellent layers 244 by the air flow B and is absorbed by the ink absorber 225. Also in the second water repellent layer 142 formed inside the first water repellent layer 141, the boundary line 253 with the hydrophilic region 228 on the nozzle 109 side of the second water repellent layer 142 has a zigzag shape. 9 and the boundary line 252 between the upper end of the fourth water repellent layer 244 in FIG. 9 and the hydrophilic region 228 has a zigzag shape, whereby the ink droplets 274 have boundary lines 252 and 253. It is easy to reach the limit angle only when exceeding. Accordingly, the ink droplets 274 extend from the hydrophilic region 228 between the first water repellent layer 141 and the second water repellent layer 142 inward and beyond the second water repellent layer 142 to between the fourth water repellent layers 244. It reaches the hydrophilic region 228 and moves from there to the ink absorber 225 over the fourth water repellent layer 244. Thus, the ink droplet 274 is absorbed by the ink absorber 225.

  Further, the first water repellent layer 141 of the water repellent layer 230 formed on the ink ejection surface 229 of the ink jet head 206 of the second embodiment covers all the vicinity of the outer periphery of the nozzle 109 belonging to each of the nozzle groups 210a and 210b. Although formed, a water repellent layer 230 ′ as shown in FIG. 10 may be used. FIG. 10 is an enlarged view showing a modification of the water repellent layer 230 formed on the ink ejection surface 229 of the inkjet head 206 according to the second embodiment of the present invention. As shown in FIG. 10, the water repellent layer 230 ′ is described above so as to surround the first water repellent layer 141 ′ formed so as to cover the vicinity of the outer periphery of each nozzle 109 and the first water repellent layer 141 ′. And an annular water repellent layer 201 in which the second to fourth water repellent layers are continuously formed. By forming the annular water-repellent layer 201 in this way, the hydrophilicity between the first water-repellent layer 141 ′ and the annular water-repellent layer 201 is caused by the flow of air when the inkjet head reciprocates, for example. The ink droplet 202 attached to the region can move not only in the direction parallel to the reciprocating direction but also in the vertical direction in FIG. Therefore, the ink droplet 202 can be easily moved away from the nozzle 109.

  As described above, also in the present embodiment, as in the first embodiment, according to the inkjet head 206, the ink droplets 271 to 274 attached to the ink ejection surface 229 cause the inertial force and air received by the reciprocating movement of the inkjet head 206. It is possible to move away from the nozzle 109 by a force from. Therefore, since the ink droplets 271 to 274 attached to the ink discharge surface 229 can be absorbed by the ink absorber 225, the ink droplets 271 to 274 can be removed from the ink discharge surface 229. As a result, it is not necessary to wipe the ink ejection surface 229 frequently, and the frequency of wiping can be reduced.

(Third embodiment)
Next, an ink jet head according to a third embodiment will be described below with reference to FIG. FIG. 11 is an explanatory diagram showing an ink ejection surface 339 of the inkjet head 306 according to the third embodiment of the present invention. In addition, about the thing similar to 1st and 2nd embodiment mentioned above, it abbreviate | omits and abbreviate | omits description.

  As shown in FIG. 11, the inkjet head 306 in the present embodiment has substantially the same configuration as the inkjet head 206 in the second embodiment, but the third water-repellent surface 329 is disposed on the ink ejection surface 329. The layer 243 is not formed, and instead, a plurality of fourth water repellent layers 244 are arranged apart from each other along the extending direction of the ink ejection surface 329. Further, only one wind direction plate 361 similar to the wind direction plate 261 described above is provided in the upper part in FIG. However, the wind direction plate 361 is disposed in the vicinity of the upper center with respect to the ink discharge surface 329, and the air flow E from the upper side to the lower side in FIG. Producing. The air flow E passes through a region where the fourth water repellent layer 244 is mainly formed by the wind direction plate 361. Further, on the ink discharge surface 329, an ink absorber 325 similar to the ink absorber 125 described above is formed on the outer periphery other than the upper portion in FIG.

  When such an inkjet head 306 prints on a sheet, the nozzle 109 ejects ink droplets while reciprocating by the drive mechanism 65 as in the first and second embodiments. At this time, for example, as shown in FIG. 11, the hydrophilicity between the first water-repellent layer 141 and the second water-repellent layer is formed on the ink ejection surface 329 due to rebound of ink droplets from the paper or ink mist. Two ink droplets 371 and 372 adhere to the sex region 228. Of the two adhered ink droplets 371 and 372, the ink droplet 271 is moved in the right direction in FIG. 11 (into the fourth water repellent layer 244) by the air flow D due to the reciprocating movement of the inkjet head 306 within the ink ejection surface 329. 11, and moves toward the lower side in FIG. 11 from the hydrophilic region 228 between the fourth water repellent layers 244 and is absorbed by the ink absorber 325 by the air flow E. On the other hand, the ink droplet 272 moves in the left direction in FIG. 11 (direction approaching the fourth water repellent layer 244) by the air flow D due to the reciprocating movement of the inkjet head 306, and the fourth water repellent by the air flow E. The ink moves from the hydrophilic region 228 between the layers 244 toward the lower side in FIG. 11 and is absorbed by the ink absorber 325. These are also the same as in the second embodiment, in the second water repellent layer 142 formed on the inner side of the first water repellent layer 141, on the nozzle 109 side of the second water repellent layer 142 and with the hydrophilic region 228. The boundary line 253 has a zigzag shape and the boundary line 252 between the upper end of the fourth water repellent layer 244 in FIG. 11 and the hydrophilic region 228 has a zigzag shape. Only when the droplets 371 and 372 exceed the boundary lines 251 and 253, the limit angle is easily reached. Accordingly, the ink droplets 371 and 372 are inward from the hydrophilic region 228 between the first water repellent layer 141 and the second water repellent layer 142 and beyond the second water repellent layer 142 to the fourth water repellent layer 244. It reaches the hydrophilic region 228 in between, and moves from there to the ink absorber 325 over the fourth water repellent layer 244. In this way, the ink droplets 371 and 372 are absorbed by the ink absorber 325.

  As described above, the inkjet head 306 in the present embodiment can also obtain the same effects as those of the second embodiment. Further, since the number of members constituting the wind direction plate 361 and the ink absorber 325 of the ink jet head 306 of the third embodiment is smaller than that of the ink jet head 206 of the second embodiment, the number of the members is smaller than that of the ink jet head 206 of the second embodiment. The configuration is simplified and the manufacturing cost is reduced.

  Next, an application example in which the present invention is applied to a vehicle window glass will be described. This application uses the inertial force and wind power received when the vehicle travels to move droplets such as rainwater adhering to the windshield of the vehicle in a desired direction to improve the driver's view. To do. For example, a plurality of transparent water repellent layers are formed on the surface of the wind glass at intervals along a predetermined direction. Here, the transparent water-repellent layer is a layer having higher water repellency than the window glass, which is formed by screen-printing a fluororesin. Thereby, the water-repellent region (second region) made of the water-repellent layer and the hydrophilic region (first region) made of the glass surface between the water-repellent layer are alternately arranged along the predetermined direction without a gap. Configured to do. In addition, the boundary line between the water-repellent region and the hydrophilic region is a zigzag line extending in a direction orthogonal to the straight line orthogonal to the predetermined direction and the straight line orthogonal to the predetermined direction, like the boundary lines 152 and 153 of the first embodiment. And alternately exist. Thereby, the droplets adhering to the window glass are easy to move in a predetermined direction and are difficult to move in a direction opposite to the predetermined direction. Therefore, if the extending direction of the boundary line is set to be orthogonal to the desired direction, the droplets attached to the window glass can be easily moved in the desired direction using the inertial force and wind force received when the vehicle travels. Can be made. From the viewpoint of facilitating the movement of the droplet, it is desirable that the extending direction of the boundary line and the direction of inertial force and wind force are orthogonal to each other. In addition, the inertial force includes not only inertial force due to a change in the traveling direction of the vehicle or acceleration / deceleration, but also inertial force based on vibrations generated from external and internal factors of the vehicle. As shown in the application examples described above, the present invention is not limited to the ink jet head of the ink jet printer, and can be freely applied to those in which attached droplets are to be moved.

(Fourth embodiment)
Next, an ink jet head according to a fourth embodiment will be described below with reference to FIGS. FIG. 12 is a bottom view of the ink ejection surface 429 of the inkjet head 406 according to the fourth embodiment of the present invention, and FIG. 13 is an enlarged view of the periphery of one nozzle 409 depicted in FIG. In addition, about the member similar to 1st-3rd embodiment mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 12, on the ink ejection surface 429 of the inkjet head 406 in the present embodiment, a plurality of nozzles 409 are two-dimensionally arranged in a matrix.

The same number of first water repellent layers 441 (third regions) and second water repellent layers 442 (second regions) as the nozzles 409 are formed on the ink ejection surface 429. The first water repellent layer 441 and the second water repellent layer 442 are made of a fluorine resin. The first water repellent layer 441 has an annular shape having an inner peripheral edge continuous with the circular opening end of the nozzle 409. The first water repellent layer 441 and the second water repellent layer 442 are separated from each other, and a first hydrophilic region 428a (first region) is formed between them. The first hydrophilic region 428a and the second water repellent layer 442 each have an annular shape. The second water repellent layers 442 are separated from each other by a second hydrophilic region 428b (first region). The second hydrophilic region 428b covers the ink ejection surface 429 other than the region where the first water repellent layer 441, the second water repellent layer 442 and the first hydrophilic region 428a are formed. The outer peripheral edge of the second hydrophilic region 428b is surrounded by an ink absorber 425 having the same annular shape as the ink absorber 125 described above.

  The outer peripheral edge of the first water-repellent layer 441, that is, the boundary line 431 between the first water-repellent layer 441 and the first hydrophilic region 428a has a circular shape (smooth curve) concentric with the nozzle 409. Therefore, the first water repellent layer 441 has an annular shape. The inner peripheral edge of the second water-repellent layer 442, that is, the boundary line 432 between the second water-repellent layer 442 and the first hydrophilic region 428a is a zigzag bent so as to sew a circle concentric with the nozzle 409 at an equal pitch. It is a line. The outer peripheral edge of the second water repellent layer 442, that is, the boundary line 433 between the second water repellent layer 442 and the second hydrophilic region 428b has a circular shape concentric with the nozzle 409.

  When such an inkjet head 406 prints on a sheet, the nozzle 409 discharges ink droplets while reciprocating by the drive mechanism 65 as in the first to third embodiments. At this time, for example, as shown in FIG. 13, the ink discharge surface 429 may be caused to bounce between the first water repellent layer 441 and the second water repellent layer 442 due to rebound of ink droplets from the paper or ink mist. The ink droplet 461 may adhere to the first hydrophilic region 428a, and the ink droplet 462 may adhere to the second hydrophilic region 428b outside the second water repellent layer 442, respectively. The adhering ink droplet 461 exceeds the second water repellent layer 442 in the direction away from the nozzle 409 due to the reciprocal movement of the inkjet head 406 and the air flow and inertia force due to the vibration of the inkjet head 406 within the ink ejection surface 429. To the second hydrophilic region 428b. This is because, in the second water repellent layer 442 formed outside the ink droplet 461, the boundary line 432 with the first hydrophilic region 428a on the nozzle 409 side of the second water repellent layer 442 has a zigzag shape. This is because the limit angle is easily reached only when the ink droplet 461 exceeds the boundary line 432 toward the outside. Therefore, when a force is applied to the ink droplet 461 in the direction away from the nozzle 409 (rightward in FIG. 13), the ink droplet 461 easily moves beyond the second water repellent film 442 to the second hydrophilic region 428b. When a force is applied in the other direction, the ink droplet 461 moves in the first hydrophilic region 428a.

  Since the second water repellent layer 442 is annular, even when the ink droplet 461 moves in the first hydrophilic region 428a, if a force is further applied in the moving direction, the second water repellent layer 442 is moved in the direction in which the force is applied as it is. It moves over the water layer 442 to the second hydrophilic region 428b. Therefore, for example, even when the wind is blowing on the ink droplet 461 from only one direction, the droplet 461 can be moved to the second hydrophilic region 428b. In this way, the ink droplet 461 can be moved to the second hydrophilic region 428b regardless of the direction of the applied force. The ink droplet 462 is absorbed by the ink absorber 425 when the ink droplet 462 moves to the ink absorber 425 by wind and inertia generated by one-way movement and vibration of the inkjet head 406, and does not reach the ink absorber 425. , It moves in the second hydrophilic region 428b and does not move beyond the second water-repellent film 442 to the first hydrophilic region 428a. Thus, the ink droplets 461 and 462 are moved away from the nozzle 409. This prevents ink discharged from the nozzles 409 from coming into contact with the ink droplets 461 and 462 and deteriorating the print quality. Moreover, generation | occurrence | production of the solidified product by the condensation of the liquid in the nozzle 409 vicinity is also prevented.

  Further, the ink discharge surface 429 of the inkjet head 406 of the fourth embodiment may be an ink discharge surface 429 ′ as shown in FIG. FIG. 14 is an enlarged view showing an ink ejection surface 429 ′ of the inkjet head 406 according to the first modification of the fourth embodiment of the present invention. As shown in FIG. 14, on the ink ejection surface 429 ′, the second repellent corresponding to the plurality of nozzles 409 arranged in one direction (vertical direction in FIG. 14) among the plurality of nozzles 409 arranged in a matrix. The water layers 442 are connected by a connecting portion 453. The connecting portion 453 is made of the same fluorine-based resin as the second water repellent layer 442, and the boundary line with the second hydrophilic region 428b (the boundary line on the left side of each connecting portion 453 in FIG. 14) has a zigzag shape. The boundary line with the other second hydrophilic region 428b (the boundary line on the right side of each connecting portion 453 in FIG. 14) has a linear shape. By forming such a connecting portion 453, the ink droplet 462 attached to the second hydrophilic region 428 b moves only to the right side of the ink ejection surface 429 beyond the connecting portion 453, so The limit angle is easily reached by the air flow and inertia force generated by the reciprocating movement and vibration, so that the ink droplet 462 easily moves to the right of the ink ejection surface 429. Accordingly, the ink droplet can be easily moved away from the nozzle 409, and the ink droplet is easily absorbed by the ink absorber 425 at the right end portion of the ink ejection surface 429 ′.

  Further, the ink ejection surface 429 of the inkjet head 406 of the fourth embodiment may be an ink ejection surface 429 ″ as shown in FIG. FIG. 15 is an enlarged view showing the ink ejection surface 429 ″ of the inkjet head 406 according to the second modification of the fourth embodiment of the present invention. As shown in FIG. 15, on the ink ejection surface 429 ″, the second water repellent layers 442 corresponding to the plurality of nozzles 409 arranged in one direction (the vertical direction in FIG. 15) are connected to each other by the connecting portion 454. The second water repellent layers 442 corresponding to the plurality of nozzles 409 arranged in a direction intersecting with this direction (left and right direction in FIG. 15) are connected to each other by a connecting portion 455. The connecting portions 454 and 455 are made of the same fluororesin as the second water repellent layer 442, and the boundary line with the second hydrophilic region 428b on the side close to the center portion 429 ″ a of the inkjet head 406 has a zigzag shape. In addition, the boundary line with the second hydrophilic region 428b on the side far from the central portion 429 ″ a of the inkjet head 406 has a linear shape. By forming such connecting portions 454 and 455, the ink droplets 462 attached to the hydrophilic region 428b pass through the connecting portions 454 and 455 and are outside the ink ejection surface 429 (in a direction away from the central portion 429 ″). Only when the ink droplets 462 are moved in the vertical direction, the ink droplets 462 attached to the hydrophilic region 428b are added to the outside of the ink ejection surface 429 in the horizontal direction by the air flow and the inertial force generated by the reciprocation and vibration of the inkjet head 406. It becomes easy to move to the outside. Therefore, the ink droplet can be easily moved away from the nozzle 409, and the ink droplet is easily absorbed by the ink absorber 425 at the peripheral portion of the ink discharge surface 429.

  As described above, also in the present embodiment, as in the first to third embodiments, according to the inkjet head 406, the inertial force that is applied to the ink droplets 461 and 462 attached to the ink ejection surface 429 by the reciprocating movement of the inkjet head 406. It can be moved away from the nozzle 409 by a force from the air or the like. Therefore, the ink droplets 461 and 462 adhering to the ink ejection surface 429 can be absorbed by the ink absorber 425, so that the ink droplets 461 and 462 can be removed from the ink ejection surface 429. As a result, it is not necessary to frequently wipe the ink discharge surface 429, and the frequency of wiping can be reduced.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. For example, the first water repellent layers 141 and 141 ′ may not be formed on the outer periphery of the nozzle 109 of the inkjet head in the first to third embodiments. Further, the third and fourth water repellent layers 243 and 244 in the second embodiment may not be formed. Further, the fourth water repellent layer 244 in the third embodiment may not be formed. Further, the first water repellent layer 441 in the fourth embodiment may not be formed. That is, it is only necessary to form an area on the ink ejection surface near the outer periphery of the nozzle 109, such as a second water repellent layer, in which ink droplets can easily move only outward from the nozzle 109. This makes it difficult for the ink droplets attached to the ink ejection surface to approach the nozzle 109. Therefore, it is possible to reduce the frequency of wiping the ink ejection surface. Further, only one second water-repellent layer may be formed on the ink discharge surface, and hydrophilic regions and second water-repellent layers are alternately arranged along the extending direction of the ink discharge surface. It does not have to be. As a result, ink droplets exceeding the second water repellent layer are less likely to approach the nozzle 109. Further, the ink jet heads 261, 262, and 361 may not be provided in the ink jet head.

  The first and second water-repellent layers are formed of the same water-repellent material. However, if the first water-repellent layer has a higher water repellency than the second water-repellent layer, the different water-repellent layers have different water repellency. The 1st and 2nd water-repellent layer may be formed from the material which has. Further, the boundary line with the hydrophilic region on the nozzle 109 side of the second water repellent layer 142 has a zigzag shape, but the boundary line may have a gentle curved shape, or a part thereof. You may only have the part which becomes a zigzag shape. Further, the inclined portion 143 having the zigzag shape of the boundary line may not be symmetric with respect to the extending direction of the ink discharge surface 129.

  In the fourth embodiment, the boundary line between the second water repellent layer 442 and the hydrophilic region 428b is circular. Further, the second water repellent region 442 may not be annular.

  Furthermore, the boundary between the second water-repellent layer 442 and the first hydrophilic region is not limited to a zigzag line like the boundary line 432, and the first to third water-repellent layers of the first embodiment of FIG. As in the regions 183a to 183c, a plurality of water repellent regions having higher liquid repellency than the first hydrophilic region 482a are formed at the boundary between the second water repellent layer 442 and the first hydrophilic region 428a, and the nozzle You may arrange | position so that the liquid repellency may improve in steps toward the direction away from 409. Alternatively, as in the hydrophilic region 193 of the first embodiment in FIG. 7, a large number of hydrophilic regions are formed at the boundary between the second water repellent layer 442 and the first hydrophilic region 428a. You may arrange | position so that the average density may reduce gradually, so that it leaves | separates. Further, like the highly water-repellent portion 199b of the first embodiment in FIG. 8, a large number of water-repellent regions are formed at the boundary between the second water-repellent layer 442 and the first hydrophilic region 428a. The average density may be gradually increased as the distance from the nozzle 409 increases. Even in these cases, the ink droplets easily flow from the first hydrophilic region 428 a over the second water repellent layer 442 to the second hydrophilic region 428 b, and the ink droplet can be moved away from the nozzle 409.

  In addition, the second water repellent layers 442 corresponding to the nozzles 409 arranged in a line like the connecting portions 453, 454, and 455 are not limited to being connected to each other, and any second water repellent layers 442 are connected to each other by the connecting portions. May be. Further, in the portion where the boundary line between the connecting portions 453, 454, 455 and the second hydrophilic region 428b is defined by the zigzag line, the second water repellent layer 442 and the first hydrophilic layer 442 described above are used instead of the zigzag line. A hydrophilic region or a water repellent region provided at the boundary with the conductive region 428a may be provided.

  Furthermore, in the fourth embodiment, an ink jet head in which a plurality of nozzles 409 are formed on the ink ejection surface 429 has been described. However, the present invention is not limited to this, and the present invention may be applied to one having one nozzle. Is possible. Also, a droplet ejecting device that ejects droplets other than ink, such as a droplet ejecting device that ejects a conductive liquid to form a conductive pattern, or a droplet ejecting device that ejects a DNA solution or a reagent to perform analysis The present invention can also be applied to.

1 is a schematic perspective view illustrating an internal configuration of a color inkjet printer according to a first embodiment of the present invention. FIG. 2 is a perspective view of a state where the head unit shown in FIG. 1 is turned upside down. FIG. 3 is a partial cross-sectional view of the inkjet head shown in FIG. 2. FIG. 4 is an enlarged plan view of an ink discharge surface of the nozzle plate shown in FIG. 3. FIG. 5A is an enlarged view of the ink ejection surface shown in FIG. 4, and FIG. It is a figure which shows the condition before passing on a 2nd water repellent layer, (c) is a figure which shows the condition after an ink drop passes on a 2nd water repellent layer with the movement of the head unit of one direction. (D) is a diagram showing the situation after the ink droplets have passed over the second water repellent layer as the head unit moves in the other direction, and (e) is a diagram showing the ink droplets on the ink absorber. It is a figure which shows the condition which moved. It is a figure which shows the 1st modification of the 2nd water repellent layer formed in the ink discharge surface of the inkjet head which concerns on 1st Embodiment of this invention. It is a figure which shows the 2nd modification of the 2nd water repellent layer formed in the ink discharge surface of the inkjet head which concerns on 1st Embodiment of this invention. It is a figure which shows the 3rd modification of the 2nd water repellent layer formed in the ink discharge surface of the inkjet head which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the ink discharge surface of the inkjet head by 2nd Embodiment of this invention. It is a figure which shows the modification of the water repellent layer formed in the ink discharge surface of the inkjet head by 2nd Embodiment of this invention. It is explanatory drawing which shows the ink discharge surface of the inkjet head by 3rd Embodiment of this invention. It is explanatory drawing which shows the ink discharge surface of the inkjet head by 4th Embodiment of this invention. It is the enlarged plan view which expanded one of the nozzles of FIG. It is explanatory drawing which shows the ink discharge surface of the inkjet head of the 1st modification of 4th Embodiment of this invention. It is explanatory drawing which shows the ink discharge surface of the inkjet head of the 2nd modification of 4th Embodiment of this invention.

Explanation of symbols

1 Inkjet printer 63 Head unit 65 Drive mechanism 66 Platen roller 107 Flow path unit
107d Nozzle plate 109 Nozzles 125, 225, 325 Ink absorbers 128a to 128e, 193, 228 Hydrophilic regions 130, 230, 230 ′ Water repellent layer 141, 141 ′ First water repellent portion 142 Second water repellent portion 151, 152 , 153, 251, 252, 253 Boundary line 183a First water repellent area 183b Second water repellent area 183c Third water repellent area 193 Hydrophilic area 199a Low water repellent part 199b High water repellent part 201 Annular water repellent layer 209 243 3rd water repellent part 244 4th water repellent part 409 Nozzle 428a 1st hydrophilic area 428b 2nd hydrophilic area 441 1st water repellent area 442 2nd water repellent area

Claims (34)

Positioned adjacent to these regions between a plurality of first regions and the two adjacent first regions on a droplet ejection surface provided with a nozzle row composed of a plurality of nozzles that eject droplets. A second region having higher liquid repellency than the first region is formed,
A first force required when a droplet existing in the first region adjacent to the second region closer to the nozzle row enters the second region is the second force. A droplet having a smaller force than a second force required when the droplet present in the first region adjacent to the region on the side away from the nozzle row enters the second region. Injection device.   2. The droplet ejecting apparatus according to claim 1, wherein the first region and the second region extend along an extending direction of the nozzle row.   The droplet ejecting apparatus according to claim 2, wherein a plurality of the first regions and at least one or more second regions are formed on both sides of the nozzle row. A plurality of the second regions are provided,
The droplet ejecting apparatus according to claim 1, wherein the plurality of first regions and the plurality of second regions are alternately formed while being adjacent to each other. .   The nozzles constituting the nozzle row are formed in a third region having the same liquid repellency as the second region, and the third region is between these two first regions. The droplet ejecting device according to claim 1, wherein the droplet ejecting device is located adjacent to the droplet ejecting device.   The droplet ejecting apparatus according to claim 1, wherein the first and second regions extend in an annular shape so as to surround the nozzle. A boundary line between the first region and the third region adjacent to the first region closer to the nozzle row is a straight line parallel to the extending direction of the nozzle row,
A boundary line between the first region and the second region adjacent to the first region on the side away from the nozzle row is a line including portions having different inclination angles. The droplet ejecting apparatus according to claim 5 or 6.   A boundary line between the first region and the second region adjacent to the first region in a direction away from the nozzle row is inclined symmetrically with respect to the extending direction of the nozzle row 2. The droplet ejecting apparatus according to claim 7, wherein the two line segments are alternately continuous lines.   In the second region, the liquid repellency is higher than that in the first region so that the liquid repellency is improved stepwise in the direction perpendicular to the extending direction of the nozzle row and away from the nozzle row. The droplet ejecting apparatus according to claim 1, wherein a plurality of high areas are provided.   In the second region, many portions having lower liquid repellency than the second region are formed, and the average density of the portions having low liquid repellency in the second region is the nozzle row. The liquid droplet ejecting apparatus according to claim 1, wherein the liquid droplet ejecting apparatus is gradually decreased in a direction perpendicular to the extending direction of the nozzle and away from the nozzle row.   In the second region, many portions having higher liquid repellency than the second region are formed, and the average density of the portions having higher liquid repellency in the second region is the nozzle row. The liquid droplet ejecting apparatus according to claim 1, wherein the liquid droplet ejecting apparatus gradually increases in a direction perpendicular to the extending direction of the nozzle line and away from the nozzle row.   12. The liquid absorber is arranged further on the side farther from the nozzle row than the second region formed farthest from the nozzle row. 12. Droplet ejector. A plurality of the nozzle rows are provided;
Between the two third regions formed for the nozzles constituting the two adjacent nozzle rows, a fourth region, adjacent to the fourth region, and more than the fourth region. The fifth regions having high liquid repellency are alternately formed in the extending direction of the nozzle row while extending in a direction orthogonal to the extending direction of the nozzle row,
For each of all the fifth regions formed between two of the third regions, the fourth region adjacent to one side in the nozzle row extending direction with respect to the fifth region. The force required when the droplet existing in the nozzle enters the fifth region is present in the fourth region adjacent to the other side in the extending direction of the nozzle row with respect to the fifth region. The droplet ejecting apparatus according to claim 5, wherein the droplet ejection force is smaller than a force required when the droplet enters the fifth region. A plurality of the nozzle rows are provided;
Between the two third regions formed for the nozzles constituting the two adjacent nozzle rows, a fourth region, adjacent to the fourth region, and more than the fourth region. The fifth regions having high liquid repellency are alternately formed in the extending direction of the nozzle row while extending in a direction orthogonal to the extending direction of the nozzle row,
Among all the fifth regions formed between the two third regions, adjacent to each other including one of the two fifth regions formed on the outermost sides in the extending direction of the nozzle row In the first group of the fifth regions, the droplets existing in the fourth region adjacent to the inner side in the extending direction of the nozzle row with respect to the fifth region enter the fifth region. Necessary force is required when droplets existing in the fourth region adjacent to the outside in the extending direction of the nozzle row enter the fifth region with respect to the fifth region. Smaller than the force,
In the second group of the fifth regions adjacent to each other including the other of the two fifth regions formed on the outermost sides in the extending direction of the nozzle row, the nozzle row with respect to the fifth region The force required when a droplet existing in the fourth region adjacent to the inside in the extending direction of the ink enters the fifth region is the extending direction of the nozzle row with respect to the fifth region. The droplet which exists in the said 4th area | region adjacent to the outer side in is smaller than the force required when entering the said 5th area | region, The one of Claims 5-12 characterized by the above-mentioned. Droplet ejector.   14. The liquid absorber is arranged outside the second region formed at the outermost side and outside the fifth region formed at the outermost side, respectively. Or the droplet ejecting apparatus according to 14. An ink jet head provided with a nozzle row comprising a plurality of nozzles for ejecting ink on an ink ejection surface;
Medium conveying means for conveying a medium on which ink ejected from the plurality of nozzles lands,
Reciprocating means for reciprocating the inkjet head in a direction orthogonal to the extending direction of the nozzle row,
The ink jet head includes two first regions extending along an extending direction of the nozzle row on the ink ejection surface, and adjacent to the two regions between the two first regions. A second region extending in the extending direction of the nozzle row and having higher liquid repellency than the first region is formed;
A first force required when an ink droplet existing in the first region adjacent to the second region in a direction approaching the nozzle row enters the second region is the second force. An ink jet printer characterized in that an ink droplet existing in the first region adjacent to the region in a direction away from the nozzle row is smaller than a second force required when entering the second region. .   The ink jet head according to claim 16, wherein the reciprocating means moves the ink jet head at a speed at which a wind force larger than the first force and smaller than the second force is applied to the droplet. Printer. A droplet moving device for moving a droplet attached to a droplet attachment surface using wind force or inertial force,
Forming the first region and the second region having higher liquid repellency than the first region alternately adjacent to each other along the predetermined direction on the droplet adhesion surface without gaps;
A first force required when a droplet existing in the first region adjacent to the second region on the side in the predetermined direction enters the second region is the second force A droplet that is present in the first region adjacent to the region on the side opposite to the predetermined direction with respect to the region is smaller than a second force required when the droplet enters the second region. Droplet moving device. A droplet ejection surface;
A nozzle that is formed on the droplet discharge surface and discharges the droplet;
A first region formed on the droplet discharge surface;
A second region having higher liquid repellency than the first region formed between the first region on the droplet discharge surface;
A first force required for a droplet to enter the second region when the droplet is present in an area closer to the nozzle than the second region in the first region is Less than the second force required for the droplet to enter the second region when the droplet is present in a region farther from the nozzle than the second region in the first region. A droplet ejection device characterized by the above.   The droplet ejecting apparatus according to claim 19, wherein the second region has a ring shape surrounding the nozzle.   21. The droplet ejecting apparatus according to claim 20, wherein an area closer to the nozzle than the second area in the first area has an annular shape surrounding the nozzle. A third region having the same liquid repellency as the second region and closer to the nozzle than the second region;
The droplet ejecting apparatus according to any one of claims 19 to 21, wherein the first region exists between the second region and the third region.   The droplet ejecting apparatus according to claim 22, wherein a boundary between the first region and the third region is defined by a straight line or a smooth curve. A boundary between the second region and the area closer to the nozzle than the second region in the first region is defined by a zigzag line;
24. The boundary between the second region and the first region and a region farther from the nozzle than the second region is defined by a straight line or a smooth curve. The droplet ejecting apparatus according to claim 1.   The liquid repellency is improved stepwise in the direction away from the nozzle at the boundary between the second region and the area closer to the nozzle than the second region in the first region. 24. The droplet ejecting apparatus according to claim 19, wherein a plurality of areas having higher liquid repellency than the first region are provided.   A number of portions having lower liquid repellency than the second region are formed at the boundary between the second region and the region closer to the nozzle than the second region in the first region. 24. The average density of the portion having low liquid repellency in the region 2 is gradually decreased in a direction away from the nozzle row. Droplet ejector.   A number of portions having higher liquid repellency than the second region are formed at the boundary between the second region and the region closer to the nozzle than the second region in the first region. 24. The average density of the portion having high liquid repellency in the region 2 is gradually increased in a direction away from the nozzle row. Droplet ejector.   28. The liquid according to claim 19, wherein a liquid absorber is disposed at a position farther from the nozzle than the first and second regions on the droplet discharge surface. Drop ejector. A plurality of the nozzles are two-dimensionally arranged on the droplet discharge surface, and the second region having a ring shape surrounding the nozzles is formed for each nozzle.
The droplet ejection according to any one of claims 19 to 28, wherein the adjacent second regions are connected to each other by a connecting portion having higher liquid repellency than the first region. apparatus.   The plurality of connecting portions connect the plurality of second regions surrounding the plurality of nozzles arranged along one direction forming a nozzle row on the droplet discharge surface. 30. A droplet ejecting apparatus according to claim 29.   A plurality of the second regions surrounding the plurality of nozzles arranged along one direction forming a nozzle row on the droplet discharge surface, and a direction intersecting the one direction 30. The droplet ejecting apparatus according to claim 29, wherein the plurality of second regions surrounding the plurality of nozzles arranged along the nozzle are connected to each other.   The first force required for the droplets to enter the connecting portion from the first region on one side of the nozzle row is from the first region on which the droplet is on the other side of the nozzle row. 32. The droplet ejecting apparatus according to claim 30, wherein the droplet ejecting apparatus is smaller than a second force required to enter the connecting portion.   Among the two first regions sandwiching each nozzle row, the droplet enters the connecting portion from the first region farther from the nozzle row of the two outermost nozzle rows. A first force required for the first region is closer to the one closer to the nozzle row of the two outermost nozzle rows of the two first regions sandwiching each nozzle row The droplet ejecting apparatus according to claim 32, wherein the droplet ejecting apparatus is smaller than a second force necessary for the droplet to enter the connecting portion from the second position.   The boundary between the first region closer to the one farther from the nozzle row of the two outermost nozzle rows of the two first regions sandwiching each nozzle row and the connecting portion is a zigzag line. The droplet ejecting apparatus according to claim 33, wherein the droplet ejecting apparatus is defined by:

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