JP2006068981A - Liquid ejecting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejecting head which can secure continuity while a high-low difference between a nozzle plate and a head cover is reduced. <P>SOLUTION: The nozzle plate is formed in a sheet shape a size smaller than a joining face of a head unit. The head cover 23 has a frame part 43 and a contact protrusion 48 which protrudes towards the inside from an inner peripheral edge of the frame part 43. An opening 42 is opened at the frame part 43, which can expose the nozzle plate in an attachment state to a head case. The frame part 43 is secured to a step part formed in the perimeter of the nozzle plate in a joining state to the joining face of the head unit. In a state in which the nozzle plate is exposed from the opening 42 and the contact protrusion 48 contacts an outer peripheral edge of the nozzle plate, the head cover 23 is attached to the head case. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid jet head such as an ink jet recording head, and in particular, a liquid jet including a nozzle plate having a nozzle row in which a plurality of nozzle openings are arranged, and capable of ejecting liquid as droplets from the nozzle openings. Regarding the head.

  Examples of liquid ejecting heads that discharge liquid droplets from nozzle openings by causing pressure fluctuations in the pressure chambers include, for example, ink jet recording heads used in image recording apparatuses such as printers, and manufacture of color filters such as liquid crystal displays. Material injection heads used in manufacturing, electrode material injection heads used for electrode formation of organic EL (Electro Luminescence) displays, FEDs (surface emitting displays), etc., and bioorganic matter injection heads used in the manufacture of biochips (biochemical elements) Etc.

  There are various types of such liquid ejecting heads. For example, an ink jet recording head (hereinafter referred to as a recording head) in an ink jet recording apparatus (hereinafter simply referred to as a printer) has a nozzle opening from a reservoir through a pressure chamber. A head unit equipped with a flow path unit in which a series of liquid flow paths leading to the pressure chamber and an actuator unit having a pressure generating element capable of changing the volume of the pressure chamber, and a plurality of nozzle openings communicating with the liquid flow path are arranged in a row Some have a nozzle plate made of metal having a nozzle row provided, and a resin head case to which the head unit and the nozzle plate are fixed.

  The head unit and nozzle plate in this recording head are fixed to the head case by a metal head cover having an opening that can expose the nozzle opening of the nozzle plate. The head cover functions to protect the flow path unit and the nozzle plate and prevent peeling of each part. Further, the head cover is set at a ground potential, and when the head cover is brought into contact with the nozzle plate and is conducted, for example, the static electricity generated from the recording paper or the like is transmitted through the nozzle plate, or the driving IC is damaged. Problems such as malfunction caused by static electricity superimposed on the drive signal as noise are prevented (for example, see Patent Document 1).

JP 2000-190513 A

  By the way, since the head cover is attached in a superposed state so as to cover the peripheral surface of the nozzle plate, the thickness of the entire head increases by the thickness of the head cover. Therefore, it is necessary to secure a longer distance (platen gap) from the nozzle opening to the recording medium so that the recording medium (discharge target) such as recording paper does not contact the head cover. However, if this platen gap is widened, when extremely small ink droplets are ejected, there is a problem that the landing position deviation of the ink droplets becomes large or the ink droplets are misted before landing on the recording medium. There is a fear.

  In addition, from the viewpoint of preventing ejection defects such as flight bending due to ink adhering to the periphery of the nozzle opening and improving the wiping property during wiping, a liquid repellent layer containing, for example, a fluororesin is provided on the surface of the nozzle plate. Thus, the liquid repellency (ink repellency) of the nozzle surface is enhanced. However, since the fluororesin has a high insulating property, if the content of the fluororesin is increased in order to improve the liquid repellency, the insulating property of the surface of the nozzle plate is increased accordingly. For this reason, there is a problem in that it is difficult to ensure conduction between the nozzle plate and the head cover in the configuration in which the head cover is superposed on the surface of the nozzle plate as in Patent Document 1 described above.

  In addition, since the boundary between the nozzle plate and the head cover is a step, the wiper blade is difficult to reach the corner of the step when wiping to wipe off excess ink droplets and dirt on the nozzle plate surface with the wiper blade. There is a risk of leaving behind. Further, when the wiper blade passes through the step, the ink wiped off may be blown off and the inside of the apparatus may be stained.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head capable of ensuring conduction while reducing a height difference between a nozzle plate and a head cover. It is in.

In order to achieve the above object, a liquid jet head according to the present invention includes a head unit including a head constituent member including a flow path unit in which a liquid flow path is formed;
A nozzle row having a plurality of nozzle openings that communicate with the liquid flow path, and a conductive nozzle plate joined to the joining surface of the head unit;
A head case to which the nozzle plate and the head unit are fixed;
A conductive head cover attached to the head case so as to surround the nozzle plate and the head unit from the outside;
The nozzle plate is formed in a plate shape slightly smaller than the joint surface,
The head cover includes a frame portion in which an opening capable of exposing the nozzle plate in an attached state to the head case is opened, and a contact protrusion that protrudes inward from the inner peripheral edge of the frame portion,
The frame portion is locked to a step portion formed around the nozzle plate in a joined state to the joining surface, the nozzle plate is exposed from the opening, and the contact protrusion is formed on the outer peripheral edge of the nozzle plate. The head cover is attached to the head case in a state in which the head contacts.
Here, with respect to the size of the nozzle plate, “one size smaller than the joining surface” means smaller than the joining surface to the extent that the frame portion of the head cover can sufficiently secure a stepped portion. .

  According to the above configuration, the head cover is attached to the head case while avoiding the nozzle plate in a state in which the frame portion is locked to the step portion formed around the nozzle plate in the joined state to the joining surface. Compared with the case where the head cover is superposed on the surface, the height difference (step) between the nozzle plate and the head cover can be reduced. This allows the wiper blade to move smoothly between the nozzle plate and the head cover during wiping, and prevents problems such as uncleaned residue and the ink wiped off by the wiper blade. Become.

  Further, as compared with the case where the head cover is superposed on the surface of the nozzle plate, the distance from the nozzle opening to the discharge target can be reduced by the thickness of the nozzle plate. As a result, it is possible to prevent as much as possible problems such as the mist of the ejected ink droplets not landing on the ejected object and the misalignment from the appropriate landing position on the ejected object.

  Further, since the contact projection of the head cover is brought into contact with the outer peripheral edge of the nozzle plate, the nozzle plate and the head cover can be electrically connected even when the surface of the nozzle plate is highly insulating. Therefore, even if the liquid repellency of the surface of the nozzle plate is increased, the nozzle plate can be adjusted to the ground potential via the head cover, thereby preventing problems such as damage to the drive IC due to static electricity or malfunctions. it can.

In the above configuration, the dimension from the tip of the one-side contact protrusion to the tip of the other-side contact protrusion at the inner peripheral edge of the frame portion is set to be shorter than the dimension of the nozzle plate in the direction sandwiched between the two contact protrusions. It is desirable that
According to this configuration, the nozzle plate in the head cover attached state is sandwiched by the contact protrusions on both sides, so that the contact protrusion of the head cover can be more reliably brought into contact with the outer peripheral edge of the nozzle plate. As a result, conduction between the nozzle plate and the head cover can be more reliably ensured.
Further, according to this configuration, even when an insulating material such as a liquid repellent layer is present on the outer peripheral edge of the nozzle plate, the liquid repellent layer or the like is peeled off with a high surface pressure of the contact protrusion, so that the conductivity of the nozzle plate is increased. Can be secured.

In the above configuration, it is preferable that a through hole that allows the contact protrusion to move outward is formed in the vicinity of the contact protrusion in the frame portion.
According to this configuration, even when the dimension between the tips of the contact protrusions on both sides is set to be shorter than the dimension of the nozzle plate, the contact protrusion is used when the nozzle plate is sandwiched between the contact protrusions on both sides. Since it can move to the outside, the head cover can be easily attached to the head case.
The term “near the abutment projection” means that the portion separating the through hole and the abutment projection has a thickness that allows the abutment projection to move to the outside so as to exhibit elasticity. Means position.

  In each of the above configurations, it is preferable that the abutment protrusion is disposed on the outer side in the nozzle row direction with respect to the nozzle row on the inner peripheral edge of the frame portion.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. The following description will be given by taking an ink jet recording apparatus (hereinafter simply referred to as a printer) as a typical liquid ejecting apparatus as an example.

  First, a schematic configuration of the printer will be described with reference to FIG. The printer 1 is an apparatus that records an image or the like by ejecting liquid ink onto the surface of a recording medium 2 (ejection target) such as recording paper. The printer 1 includes an ink jet recording head 3 that discharges ink (corresponding to a kind of liquid ejecting head of the present invention, hereinafter referred to as a recording head), a carriage 4 to which the recording head 3 is attached, and a carriage 4 in the main scanning direction. A carriage moving mechanism 5 for moving, a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction, and the like are provided. Here, the above ink is a kind of liquid of the present invention, and is stored in the ink cartridge 7 (liquid storage member). The ink cartridge 7 is detachably attached to the recording head 3.

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

  A wiping mechanism 11 for wiping the nozzle forming surface (nozzle plate 21 / see FIGS. 2 and 3) of the recording head 3 mounted on the carriage 4, for example, is disposed at the home position, which is a non-recording area of the printer 1. Has been. The wiping mechanism 11 has a wiper blade 11 ', and the wiper blade 11' is composed of an elastic member such as rubber or elastomer. The wiping mechanism 11 positions the wiper blade 11 ′ so that the tip of the wiper blade 11 ′ intersects the movement locus of the nozzle forming surface of the recording head 3 during wiping. Then, as the recording head 3 passes, the tip of the wiper blade 11 ′ slides on the nozzle forming surface, thereby wiping the nozzle forming surface.

  A capping mechanism 12 is disposed adjacent to the wiping mechanism 11 at or near the home position. The capping mechanism 12 has a tray-like cap member 12 ′ that can come into contact with the nozzle forming surface of the recording head 3. In the capping mechanism 12, the space in the cap member 12 'functions as a sealing empty portion, and is configured to be able to closely contact the nozzle forming surface with the nozzle opening of the recording head 3 facing the sealing empty portion. Yes. Further, a pump unit 13 is connected to the capping mechanism 12, and the inside of the sealed empty space can be made negative pressure by the operation of the pump unit 13. When the pump unit 13 is operated in close contact with the nozzle forming surface and the inside of the sealing empty portion (sealed space) is made negative, ink and bubbles in the recording head 3 are sucked from the nozzle openings and the cap member 12 is sucked. It is discharged into the sealed empty space of '.

  2 and 3 are diagrams for explaining the configuration of the recording head 3. FIG. 2 is an exploded perspective view of the recording head 3 viewed from obliquely above, and FIG. 3 is an exploded perspective view of the recording head 3 viewed from obliquely below. FIG. The recording head 3 has a supply needle unit 17 provided with a plurality of ink supply needles 16 for introducing the ink in the ink cartridge 7 into the head, and head constituent members such as an actuator unit 18 and a flow path unit 19. The head case 22 includes a head unit 20 and a nozzle plate 21 having a nozzle row 38 (see FIG. 4) in which a plurality of nozzle openings are arranged in a row. In the recording head 3, the side of the head unit 20 and the nozzle plate 21 is protected on the tip side of the head case 22 (the side opposite to the bonding surface of the supply needle unit 17), and the nozzle plate 21 is grounded. A head cover 23 for adjusting the potential is attached.

  The supply needle unit 17 is a member made of synthetic resin in which the ink supply needles 16 are arranged side by side in the head main scanning direction (the nozzle row orthogonal direction). The tip of the ink supply needle 16 disposed in the supply needle unit 17 has a conical point and is easy to insert into the ink cartridge 7. In addition, a plurality of introduction holes communicating with the inside and outside of the ink supply needle 16 are formed at the tip, and ink in the ink cartridge 7 is introduced into the head through these introduction holes. Since the recording head 3 of the present embodiment can eject four types of ink, the supply needle unit 17 is provided with a total of four ink supply needles 16 in a posture with the tip protruding upward. .

  The head case 22 has a base portion 25 to which the supply needle unit 17 and the wiring board 24 are attached, and a hollow box-like shape that extends downward from the bottom portion of the base portion 25 and has the head unit 20 attached to the opening surface. This is a member constituted by the case portion 26. In the present embodiment, as a material for the head case 22 and the supply needle unit 17, for example, a thermoplastic resin such as a modified PPE (polyphenylene ether) resin is used.

  In the base portion 25 of the head case 22, an upper opening 27 of a converging flow path (not shown) for supplying ink to the head unit 20 side is opened at a position corresponding to each ink supply needle 16 of the supply needle unit 17. Has been. The base portion 25 is partitioned with a substrate placement portion 28 on which the wiring substrate 24 is placed. The wiring board 24 is a board on which electronic components for various driving signals are mounted and connection terminals to which one end side terminals of the flexible cable 29 of the actuator unit 18 are connected are formed. In addition, the wiring board 24 includes a connector 36. A control cable (none of which is shown) such as an FFC (flexible flat cable) from the control device is electrically connected to the connector 36.

  When the supply needle unit 17 is attached to the base portion 25, the needle flow path in the ink supply needle 16 and the convergence flow path in the head case 22 communicate with each other, and the ink introduced from the ink supply needle 16 converges. It is supplied to the head unit 20 side through a path.

  The head unit 20 is composed of an actuator unit 18 and a flow path unit 19, which are integrated in a superposed state. The actuator unit 18 includes a pressure chamber plate in which a pressure chamber corresponding to a nozzle opening is formed, a communication port plate in which a communication port is formed, and a vibrator plate on which a piezoelectric vibrator is mounted. A flexible cable 29 such as a tape carrier package is provided in a state where the other end side terminal is electrically connected to the terminal portion of the piezoelectric vibrator. The piezoelectric vibrator in the actuator unit 18 is a so-called flexural vibration mode piezoelectric vibrator. When the piezoelectric vibrator is driven, that is, flexurally vibrated, the volume of the pressure chamber changes and ink droplets are ejected from the nozzle openings. It has come to be.

  The flow path unit 19 includes a supply port plate 32 that forms an ink supply port 30 and a compliance portion 31 that relieves pressure fluctuations of the reservoir, and a plurality of reservoirs 33 that are supplied with ink introduced from the ink cartridge 7 side. The reservoir plate 34 is formed with a common liquid chamber. The supply port plate 32 and the reservoir plate 34 are bonded together by a heat welding film or the like in a laminated state, and form an ink flow path (liquid flow path in the present invention) from the reservoir 33 to the nozzle opening. . The surface opposite to the supply port plate bonding surface of the reservoir plate 34, that is, the bottom surface of the head unit 20 is a bonding surface 35 to which the nozzle plate 21 is bonded.

  FIG. 4 is a plan view illustrating the configuration of the nozzle plate 21. In the drawing, the nozzle plate 21 in a state of being bonded to the bonding surface 35 of the head unit 20 is shown. As a material of the nozzle plate 21, a conductive material, for example, a large material substrate such as stainless steel is used. Then, after opening the nozzle openings on the material substrate and applying a liquid repellent treatment to one surface (the surface on the ink droplet ejection side), a plurality of nozzle plates 21 are cut out from the material substrate. Therefore, the liquid repellent layer is formed only on the surface of the nozzle plate 21.

The nozzle plate 21 is formed with a nozzle row 38 in which a plurality of nozzle openings communicating with the liquid flow path of the flow path unit 19 are arranged. In the present embodiment, the nozzle plate 21 corresponds to four types of ink. A total of four nozzle rows 38 are formed. The nozzle plate 21 is formed slightly smaller than the joint surface 35 of the head unit 20. Therefore, when the nozzle plate 21 is bonded to the bonding surface 35 of the head unit 20, a step 40 that is lower by the thickness is formed around the nozzle plate 21 on the bonding surface 35. The step portion 40 serves as a locking allowance for locking the frame portion 43 (see FIGS. 5 and 6B) of the head cover 23 when the head cover 23 is attached to the head case 22.
As for the size of the nozzle plate 21, “one size smaller than the joining surface 35” means a size that can secure the stepped portion 40 that the frame portion 43 of the head cover 23 can sufficiently lock. It is a meaning to represent.

  Here, the supply port plate 32 and the reservoir plate 34 and the nozzle plate 21 in the flow path unit 19 have an insertion hole h through which a reference pin 51 for positioning them in the head case 22 can be inserted. Two positions are provided at positions corresponding to the reference pins 51. Then, the head unit 20 and the nozzle plate 21 are fixed to the head case 22 in a posture in which the nozzle plate 21 faces downward after the reference pins 51 are inserted into the respective insertion holes h so that the relative positions thereof are matched. Is done. Further, a head cover 23 is attached to the front end side of the head case 22 so as to surround the head unit 20 and the nozzle plate 21 from the outside.

  5A and 5B are diagrams for explaining the configuration of the head cover 23, where FIG. 5A is a perspective view of the head cover 23, FIG. 5B is a plan view of the head cover 23, and FIG. 5C is an enlarged view of a region A in FIG. is there. The head cover 23 is made of a conductive member such as stainless steel like the nozzle plate 21, and has a frame portion 43 having an opening 42 in the central portion and an outer peripheral edge of the frame portion 43 (see FIG. 5 (b) and the side wall 44 extending toward the head case 22 side. The side surface portions 44 on both sides in the nozzle row orthogonal direction extend a flange portion 45 toward the side, and a fixing pin 46 for attaching to the head case 22 is inserted into the flange portion 45. A hole H is established. The side surface portion 44 is connected to an earth line (not shown) that leads to the printer 1 side. Thereby, the head cover 23 is configured to be adjusted to the ground potential.

  The opening 42 of the head cover 23 has a shape that follows the outer peripheral shape of the nozzle plate 21, and the dimension (inner dimension) is set slightly larger than the nozzle plate 21. Therefore, when the head cover 23 is attached to the head case 22, the nozzle plate 21 is exposed from the opening 42.

  The frame portion 43 is formed in a substantially rectangular frame shape, and is a portion that engages with the step portion 40 in the joint surface 35 of the head unit 20. The frame portion 43 is formed with a tapered portion 47 (see FIG. 6) whose thickness gradually decreases toward the opening 42 side (inner peripheral edge side). The thickness of the tip portion of the taper portion 47 (the inner peripheral edge portion of the frame portion 43) is aligned with the thickness of the nozzle plate 21.

  In addition, a plurality of contact protrusions 48 protruding inward are provided integrally with the frame portion 43 on the inner peripheral edge of the frame portion 43, that is, the opening edge of the opening portion 42. As shown in FIG. 5C, the contact protrusion 48 in the present embodiment is a minute protrusion having a substantially triangular shape in plan view, and is located on one side in the nozzle row direction on the inner peripheral edge of the frame portion 43 (FIG. A total of four locations are provided, two on each of the upper side in b) and the other side (lower side in FIG. 5B). The dimension from the tip of one contact protrusion 48 to the tip of the other contact protrusion 48 facing the other (hereinafter referred to as the distance between the tips) is the direction between the contact protrusions 48 (this In the embodiment, it is set slightly shorter than the dimension of the nozzle plate 21 in the nozzle row direction). Specifically, for example, when the gap between the nozzle plate 21 and the frame portion 43 when exposed from the opening 42 (without considering the presence of the contact protrusion 48) is 0.1 mm, each contact protrusion The protrusion length of 48 is set to about 0.2 mm. That is, each contact protrusion 48 is dimensioned so as to overlap the nozzle plate 21 by at least about 0.1 mm. Therefore, when the head cover 23 is attached to the head case 22 and the nozzle plate 21 is exposed from the opening 42, the nozzle plate 21 is sandwiched between the contact protrusions 48 on both sides.

Since the head cover 23 is made of a relatively hard material such as stainless steel as described above, it is difficult to elastically deform as it is, and it is difficult to sandwich the nozzle plate 21 between the contact protrusions 48. . Therefore, as shown in FIG. 5 (c), through holes 49 are formed in the vicinity of the contact protrusions 48 in the frame portion 43, so that the contact protrusions 48 are formed on the outer side (through hole 49 side). The nozzle plate 21 can be easily sandwiched between the contact protrusions 48 by allowing the movement.
Note that “the vicinity of the contact protrusion 48” is determined such that the portion separating the through hole 49 and the contact protrusion 48 has a thickness that can exert elasticity that allows the contact protrusion 48 to move outward. Means the position of the through-hole 49.

  In the present embodiment, the through hole 49 is a long hole that is long in a direction orthogonal to the protruding direction of the contact protrusion 48, and is formed in the tapered portion 47 of the frame portion 43. The portion that separates the through hole 49 and the contact protrusion 48 is a thin portion 50 that is relatively thin in the protruding direction of the contact protrusion 48, and the thin portion 50 is elastically deformed to the outside of the contact protrusion 48. It is possible to move. Therefore, since the ease of movement of the contact protrusion 48 is determined according to the thickness of the thin portion 50 and the size of the through hole 49, the thickness of the thin portion 50 and the size of the through hole 49 are determined by the contact protrusion 48. It is desirable that the thickness be set to such an extent that the thin portion 50 exhibits elasticity that allows the contact protrusion 48 to move outward, while ensuring rigidity that can reliably contact the outer peripheral edge of the nozzle plate 21.

  6A and 6B are diagrams showing the recording head 3 in a state where the respective constituent members are assembled. FIG. 6A is a plan view of the recording head 3 viewed from the nozzle plate 21 side, and FIG. It is line sectional drawing. As shown in the figure, the head cover 23 has a frame portion 43 locked to a stepped portion 40 formed around the nozzle plate 21 in a joined state to the joining surface 35, and the tip of each contact projection 48 is the nozzle plate. The nozzle plate 21 is exposed from the opening 42 in contact with the outer peripheral edge of the head 21, and is attached to the head case 22 by a fastening pin 46.

  As described above, the head cover 23 is attached to the head case 22 while avoiding the nozzle plate 21 in a state in which the frame portion 43 is locked to the stepped portion 40 formed around the nozzle plate 21 in the joined state to the joining surface 35. Therefore, the height difference (step) between the nozzle plate 21 and the head cover 23 can be reduced as compared with the case where the head cover is superposed on the surface of the nozzle plate. As a result, the wiper blade 11 ′ during wiping can smoothly move on the boundary between the nozzle plate 21 and the head cover 23, thereby preventing problems such as unwiping of dirt and splashing off the ink wiped off by the wiper blade. It becomes possible.

  Further, the frame portion 43 in the present embodiment is formed with a taper portion 47, and the thickness of the tip portion of the taper portion 47 is equal to the thickness of the nozzle plate 21, so that the wiper blade 11 ' However, it is possible to move the boundary portion between the head cover 23 and the nozzle plate 21 more smoothly, and it is possible to more effectively prevent problems such as dirt remaining after wiping.

  Further, compared to the case where the head cover is superposed on the surface of the nozzle plate, the distance (platen gap) from the nozzle opening to the recording medium 2 can be reduced by the thickness of the nozzle plate 21. As a result, it is possible to prevent as much as possible problems such as the ejected ink droplets being misted without landing on the recording medium 2 or being displaced from the appropriate landing position on the recording medium 2.

  Furthermore, since the contact protrusion 48 of the head cover 23 is brought into contact with the outer peripheral edge of the nozzle plate 21 where the liquid repellent layer is not formed, the nozzle plate 21 can be used even when the surface of the nozzle plate is highly insulating. And the head cover 23 can be conducted. Therefore, even if the surface insulation of the nozzle plate 21 becomes higher as the liquid repellency is enhanced, the nozzle plate 21 can be adjusted to the ground potential through the head cover 23, and damage to the driving IC or the like due to static electricity. And malfunctions such as malfunctions can be prevented.

  Further, in the present embodiment, the distance between the tips of the contact projections 48 on one side and the other side on the inner peripheral edge of the frame portion 43 is set to be shorter than the dimension of the nozzle plate 21, so the nozzle plate 21 It is clamped by the contact protrusion 48. Therefore, each contact protrusion 48 can be brought into contact with the outer peripheral edge of the nozzle plate 21 more reliably. As a result, conduction between the nozzle plate 21 and the head cover 23 can be more reliably ensured. Further, since the nozzle plate 21 is sandwiched between the contact protrusions 48 on both sides, it is possible to prevent the nozzle plate 21 from being peeled off or dropped from the joining surface 35. Furthermore, even when an insulating material such as a liquid repellent layer is present on the outer peripheral edge of the nozzle plate 21, the insulating material such as the liquid repellent layer is peeled off by a high surface pressure between the contact protrusions 48, thereby making the conductivity of the nozzle plate. Can be secured.

  Further, as described above, since the through hole 49 that allows the contact protrusion 48 to move outward is provided in the vicinity of the contact protrusion 48 in the frame portion 43, the distance between the tips as in this embodiment is provided. The head cover 23 can be easily attached to the head case 22 even when is set shorter than the dimension of the nozzle plate 21.

  By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.

  In the above embodiment, the contact protrusion 48 is provided on one side and the other side in the nozzle row direction on the inner peripheral edge of the frame portion 43, but the present invention is not limited thereto. For example, the contact protrusions 48 can be provided on one side and the other side in the direction perpendicular to the nozzle row 38 on the inner peripheral edge of the frame portion 43. At this time, in order to prevent the wiper blade from being damaged by the contact protrusions 48, the contact protrusions 48 are arranged on the inner peripheral edge of the frame portion 43 so as not to hinder the wiping of the nozzle openings. It is desirable that the nozzles be disposed outside the row 38 in the nozzle row direction.

  Moreover, regarding the number of the contact protrusions 48, in the above-described embodiment, an example in which a total of four is provided has been described. However, the number of contact protrusions 48 is not limited thereto.

  In the above, the ink jet recording head 3 which is a kind of liquid ejecting head has been described as an example, but the present invention can also be applied to other liquid ejecting heads. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, an FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of

FIG. 2 is a perspective view illustrating a configuration of a printer. FIG. 3 is an exploded perspective view of the configuration of the recording head as viewed obliquely from above. FIG. 3 is an exploded perspective view of the configuration of the recording head as viewed obliquely from below. It is a top view explaining the structure of a nozzle plate. It is a figure explaining the structure of a head cover, (a) is a perspective view, (b) is a top view, (c) is an enlarged view of the area | region A in (b). 2A and 2B are diagrams illustrating the recording head in a state where the head cover is attached to the head case, where FIG. 2A is a plan view of the recording head viewed from the nozzle plate side, and FIG. 2B is a cross-sectional view taken along line AA in FIG. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording medium, 3 ... Recording head, 4 ... Carriage, 5 ... Carriage moving mechanism, 6 ... Platen roller, 7 ... Ink cartridge, 8 ... Timing belt, 9 ... Pulse motor, 10 ... Guide rod, 11 DESCRIPTION OF SYMBOLS ... Wiping mechanism, 12 ... Capping mechanism, 13 ... Pump unit, 16 ... Ink supply needle, 17 ... Supply needle unit, 18 ... Actuator unit, 19 ... Flow path unit, 20 ... Head unit, 21 ... Nozzle plate, 22 ... Head Case, 23... Head cover, 24 .. wiring board, 25 .. base portion, 26 .. case portion, 27 .. upper opening, 28 .. substrate mounting portion, 29 .. flexible cable, 30. ... Supply port plate, 33 ... Reservoir, 34 ... Reservoir plate, 35 ... Joint surface, 3 ... Connector, 38 ... Nozzle row, 40 ... Step part, 42 ... Opening part, 43 ... Frame part, 44 ... Side face part, 45 ... Flange part, 46 ... Fastening pin, 47 ... Taper part, 48 ... Contact protrusion, 49 ... Through hole, 50 ... Thin part, 51 ... Reference pin

Claims (4)

A head unit having a head constituent member including a flow path unit in which a liquid flow path is formed;
A nozzle row having a plurality of nozzle openings that communicate with the liquid flow path, and a conductive nozzle plate joined to the joining surface of the head unit;
A head case to which the nozzle plate and the head unit are fixed;
A conductive head cover attached to the head case so as to surround the nozzle plate and the head unit from the outside;
The nozzle plate is formed in a plate shape slightly smaller than the joint surface,
The head cover includes a frame portion in which an opening capable of exposing the nozzle plate in an attached state to the head case is opened, and a contact protrusion that protrudes inward from the inner peripheral edge of the frame portion,
The frame portion is locked to a step portion formed around the nozzle plate in a joined state to the joining surface, the nozzle plate is exposed from the opening, and the contact protrusion is formed on the outer peripheral edge of the nozzle plate. The liquid ejecting head, wherein the head cover is attached to the head case in a state where the head is in contact with the head.   The dimension from the tip of the contact protrusion on one side to the tip of the contact protrusion on the other side at the inner peripheral edge of the frame portion is set to be shorter than the dimension of the nozzle plate in the direction sandwiched between both contact protrusions. The liquid ejecting head according to claim 1, wherein the liquid ejecting head is a liquid ejecting head.   The liquid ejecting head according to claim 2, wherein a through hole that allows the contact protrusion to move outward is formed near the contact protrusion in the frame portion. 4. The liquid ejecting head according to claim 1, wherein the contact protrusion is disposed outside the nozzle row in an inner peripheral edge of the frame portion in the nozzle row direction. 5. .

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