Liquid ejecting head

A conductive nozzle plate is formed with a nozzle orifice. An insulative layer is formed on a first face of the nozzle plate. A head body includes a pressure chamber adapted to contain liquid therein and a pressure generating element operable to cause pressure fluctuation in the liquid. The head body is attached to a second face of the nozzle plate so as to communicate the pressure chamber with the nozzle orifice. The second face of the nozzle plate and the head body are fixed to a head case. A conductive head cover covers a part of the first face of the nozzle plate while exposing the nozzle orifice. A part of the nozzle plate and the head cover directly come into contact with each other.

BACKGROUND OF THE INVENTION

The present invention relates to a liquid ejecting head, such as an ink jet type recording head, and more particularly, to a liquid ejecting head which is provided with a nozzle forming member having a plurality of nozzle orifices formed thereon and which can eject liquid from the nozzle orifices in forms of liquid droplets. The present invention also relates to a method of manufacturing such a liquid ejecting head.

As a liquid ejecting head which causes a pressure change of liquid within a pressure chamber so as to eject liquid droplets from the nozzle orifices, for example, an ink jet type recording head which is used in an image recording apparatus, such as a printer or the like, a color material ejecting head which is used for manufacturing a color filter of a liquid crystal display or the like, an electrode material ejecting head which is used for forming electrodes of an organic electroluminescent (EL) display, a field emission display (FED), or the like, a biological organic material ejecting head which is used for manufacturing a bio chip (biochemical element), and the like can be used.

Of various types of liquid ejecting heads, for example, an ink jet type recording head (hereinafter, referred to as recording head) in an ink jet type recording apparatus (hereinafter, simply referred to as printer) is provided with a head unit (head main body) having a flow passage unit, in which a liquid flow passage from a reservoir to nozzle orifices through a pressure chamber is formed, or an actuator unit having a pressure generating element which can change a volume of the pressure chamber, a metallic nozzle plate having nozzle lines, in which a plurality of nozzle orifices are provided to be connected with the liquid flow passage, and a head case, made of resin, to which the head unit and the nozzle plate (a type of nozzle forming member) are fixed.

In such a recording head, flight deviation may occur in liquid droplets to be ejected according to a state around the nozzle orifice, that is, a state in which liquid, such as ink or the like, wets around the nozzle orifice. That is, if liquid, such as ink or the like, wets around the nozzle orifice, liquid droplets are pulled by a surface tension of that part at the time of eject, which causes flight deviation. In general, in order to prevent flight deviation, a liquid repellent treatment for preventing adhesion of liquid, such as ink or the like, around the nozzle orifice is performed on a liquid ejecting surface of the nozzle plate.

The nozzle plate in the recording head is fixed to the head case by the metallic head cover having an exposure window, through which the nozzle orifices of the nozzle plate are exposed. The head cover has a function of protecting the head unit or the nozzle plate and preventing the individual parts from being separated. In addition, the head cover, which is set to a ground potential, comes into contact with the nozzle plate to be electrically connected thereto, thereby removing static electricity generated in recording paper or the like from the nozzle plate. Accordingly, for example, an inconsistency, such as an electrostatic breakdown of a driving circuit or the like caused by static electricity to be transferred through the nozzle plate, or an inconsistency, or an erroneous operation caused by the superimposition of the static electricity on a driving signal as noise can be prevented. Such a configuration is disclosed in, for example, Japanese Patent Publication Nos. 2004-74676A and 2000-190513A.

Recently, however, in such a printer, there is a tendency that pigment-based ink for improving image quality or water-resistant ink for improving water resistance is used. As a solvent of such ink, instead of water, a resin-based dispersing agent is used. For this reason, a liquid repellent coating layer, which is formed on the liquid ejecting surface of the nozzle plate so as to prevent defective eject, such as flight deviation caused by ink adhesion around the nozzle orifice, needs to have high liquid repellency according to such ink. Further, in order to reduce manufacturing costs by simplifying a coating treatment process, in addition to the significant improvement of liquid repellency or quality, the liquid repellent treatment is performed on the liquid ejecting surface of the nozzle plate, for example, using a thin film deposition technology. With the liquid repellent treatment, a liquid repellent coating layer, which contains more fluorine resin is formed on the liquid ejecting surface of the nozzle plate. However, if the content ratio of fluorine resin is increased in order to enhance liquid repellency, an insulation property of the liquid ejecting surface of the nozzle plate is increased accordingly, since fluorine resin has a high insulation property.

On the other hand, as the water repellent film with an improved water repellent performance, the use of a glassy insulating film has been examined, as described in Japanese Patent Publication No. 2004-351923A.

If such a liquid repellent coating layer or an insulating film is formed on the nozzle surface of the nozzle plate, the nozzle plate and the head cover face each other through the insulating film when the head cover is simply mounted as described the above, and thus the static electricity flying from the paper to the nozzle plate or the charges of the nozzle plate cannot be released through the head cover.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a liquid ejecting head which can ensure an electrical connection between a nozzle forming member and a head cover, even when liquid repellency of a liquid ejecting surface of the nozzle forming member is improved.

In order to achieve the above object, according to the invention, there is provided a liquid ejection head, comprising:

a conductive nozzle plate, formed with a nozzle orifice;

an insulative layer, formed on a first face of the nozzle plate;

a head body, including a pressure chamber adapted to contain liquid therein and a pressure generating element operable to cause pressure fluctuation in the liquid, the head body attached to a second face of the nozzle plate so as to communicate the pressure chamber with the nozzle orifice;

a head case, to which the second face of the nozzle plate and the head body are fixed; and

a conductive head cover, covering a part of the first face of the nozzle plate while exposing the nozzle orifice, wherein a part of the nozzle plate and the head cover directly come into contact with each other.

A projection may be formed on the head cover so as to come in contact with the nozzle plate through the insulative layer.

The head cover may include a frame portion covering the part of the first face of the nozzle plate and a window portion exposing the nozzle orifice. The projection may be formed on an inner peripheral edge of the window portion.

The head cover may include a through hole adapted to receive a pin member for fixing the head cover to the head case. The projection may be formed on an inner peripheral edge of the through hole.

A projection may be formed on the first face of the nozzle plate. The insulative layer may be removed from a top face of the projection so that the top face of the projection comes in contact with the head cover.

A height dimension of the projection may be greater than a thickness dimension of the insulative layer.

A recess may be formed on the second face of the nozzle plate so as to oppose the projection.

A recess may be formed on the first face of the nozzle plate, and the projection may be formed around the recess.

The projection may be formed in the vicinity of an edge of the nozzle plate.

The head cover may include a fixing portion adapted to receive a screw member for fixing the head cover to the head case. The projection may be formed in the vicinity of the fixing portion.

The head cover may include a fixing portion adapted to receive a screw member for fixing the head cover to the head case. The projection may be formed in a region receiving a torque generated when the screw member is screwed.

A position of the projection may indicate a position in a mother conductive plate from which the nozzle plate is cut out.

The insulative layer may include a liquid repellent coating.

The nozzle plate may be grounded via the head cover.

According to the invention, there is also provided a method of manufacturing a liquid ejecting head, comprising:

providing a conductive nozzle plate formed with a nozzle orifice;

forming an insulative layer on a first face of the nozzle plate;

attaching a head body including a pressure chamber adapted to contain liquid therein and a pressure generating element operable to cause pressure fluctuation in the liquid, to a second face of the nozzle plate so as to communicate the pressure chamber with the nozzle orifice;

fixing the second face of the nozzle plate and the head body to a head case;

covering a part of the first face of the nozzle plate with a conductive head cover, while exposing the nozzle orifice; and

bringing a part of the nozzle plate and the head cover into direct contact with each other.

The manufacturing method may further comprise: forming a projection on the head cover; and bringing the projection into contact with the nozzle plate through the insulative layer.

The manufacturing method may further comprise: forming a projection on the first face of the nozzle plate; removing the insulative layer from a top face of the projection; and bringing the top face of the projection into contact with the head cover.

The manufacturing method may further comprise forming a recess on the second face with laser marking, thereby forming the projection.

The manufacturing method may further comprise forming a recess on the second face with press working, thereby forming the projection.

The manufacturing method may further comprise forming a recess on the first face with laser marking, thereby forming the projection.

The manufacturing method may further comprise: providing a mother conductive plate adapted such that a plurality of nozzle plates are cut out therefrom; and forming the projection on each of the nozzle plates such that a position of the projection indicates a position of each nozzle plate in the mother conductive plate.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the following description, an ink jet type recording apparatus (hereinafter, simply referred to as printer), which is a representative liquid ejecting apparatus, will be exemplified.

As shown inFIG. 1, a printer101according to the first embodiment is an apparatus which ejects liquid ink onto the surface of a recording medium102, such as recording paper or the like, so as to record images or the like. The printer101is provided with an ink jet type recording head103(hereinafter, is referred to as recording head) which ejects ink, a carriage104on which the recording head103is mounted, a carriage moving mechanism105which moves the carriage104in a primary scanning direction, and a platen roller106which transfers the recording medium102in a secondary scanning direction. Here, ink, which is a type of liquid of the present invention, is stored in an ink cartridge107. The ink cartridge107can be detachably mounted with respect to the recording head103.

The carriage moving mechanism105is provided with a timing belt108, which is driven by a pulse motor109, such as a direct-current (DC) motor. Therefore, if the pulse motor109operates, the carriage104is guided to a guide rod110erected in the printer101so as to reciprocate in the primary scanning direction (a widthwise direction of the recording medium102).

As shown inFIGS. 2 and 3, the recording head103comprises, in a head case118, a supply needle unit112in which a plurality of ink supply needles111for introducing ink within the ink cartridge107into the head103are provided, a head unit115having head constituting members, such as an actuator unit113, a flow passage unit114, and the like, and a nozzle plate117having nozzle arrays116in which a plurality of nozzle orifices are provided. Further, in the recording head103, a head cover119is mounted on the front end of the head case118so as to protect side portions of the head unit115or the nozzle plate117and to adjust the nozzle plate117to have a ground potential.

The head case118is a member having a base section121on which the supply needle unit112and a wiring board120are mounted, and a hollow box-shaped case section122which extends downward from the bottom portion of the base section121and in which the head unit115is mounted on an opened face thereof. The head case118and the ink supply needle unit112are formed of, for example, epoxy-based synthetic resin or the like.

In the base section121of the head case18, a substrate disposing section123in which the wiring board120is disposed is partitioned. The wiring board120is a board on which electronic components for various driving signals are mounted and connection terminals are formed to be connected to terminals at one end of a flexible cable124of the actuator unit113. In addition, the wiring board120includes a connector125to which control cables, such as flexible flat cables (FFCs) or the like, are electrically connected, though not shown.

The head unit115has the actuator unit113and the flow passage unit114, which overlap each other to be unitized. The actuator unit113has a laminated body of a pressure chamber plate having a pressure chamber formed to correspond to the nozzle orifice, a connection port plate having a connection port formed therein, and a vibration plate on which a piezoelectric vibrator is mounted. Further, the actuator unit113has the flexible cable124, such as a tape carrier package (TCP) or the like, a terminal at the other end of which is electrically connected to the terminal section of the piezoelectric vibrator. The piezoelectric vibrator in the actuator unit113is a piezoelectric vibrator in a so-called deflection vibration mode. If the piezoelectric vibrator is driven, that is, deflection-vibrated, the volume of the pressure chamber changes, such that an ink droplet (liquid droplet) is ejected from the nozzle orifice.

The flow passage unit114has a supply port plate132in which an ink supply port130and a compliance section131for relaxing the pressure change of a reservoir are formed, and a reservoir plate134in which a plurality of reservoirs133supplied with ink introduced from the ink cartridge are formed. The supply port plate132and the reservoir plate134are laminated and bonded to each other by a thermal welding film or the like, thereby forming an ink flow passage from the reservoir133to the nozzle orifice. Further, a surface of the reservoir plate134opposite to the bonded surface to the supply port plate132, that is, the bottom surface of the head unit115is bonded to the nozzle plate117.

As the nozzle plate117, a large material substrate made of, for example, stainless steel having conductivity is used. After nozzle orifices are formed in the material substrate and one surface to be a liquid ejecting surface is subjected to a liquid repellent treatment, the plurality of nozzle plates117are cut out from the material substrate. Therefore, a liquid repellent coating layer135is formed only on the liquid ejecting surface of the nozzle plate117.

Moreover, as the nozzle forming member in the present embodiment, the nozzle plate117, which is formed of a metal substrate, such as stainless steel, is exemplified but is not limited thereto. For example, other materials may be used, as long as at least the liquid ejecting surface is formed of a metallic base material having conductivity.

The liquid repellent coating layer135containing fluorine resin is coated on the liquid ejecting surface of the nozzle plate117by a thin film deposition technology. Accordingly, in addition to the improvement of liquid repellency and durability, manufacturing costs can be reduced by simplifying a liquid repellent coating process.

In the supply port plate132and the reservoir plate134of the flow passage unit114, the nozzle plate117, and a frame section140of the head cover119, which is mounted to overlap the nozzle plate117, two positioning holes142open at positions corresponding to positioning pins141. The positioning pins141can be correspondingly inserted into the positioning holes142so as to position the supply port plate132, the reservoir plate134, the nozzle plate117, and the frame section140in the head case118. When the positioning pins141are correspondingly inserted into the positioning holes142, the head unit115and the nozzle plate117are relatively positioned, and are fixed to the head case118in a state in which the nozzle plate117is on the lower side. Further, after the positioning pins141are inserted for positioning, the head cover119is mounted on the front end of the head case118so as to surround the head unit115and the nozzle plate117from the outside.

Next, the head cover119will be described. As shown inFIGS. 4Aand4B, the head cover119, which is formed of a metallic plate, such as stainless steel or the like having conductivity, like the nozzle plate117, schematically has the frame section140in which an exposure window143opens at the center, and side wall sections144which extend from the outer circumferential edge of the frame section140toward the head case118. Further, in both the side wall sections144(seeFIG. 5) in a direction perpendicular to the nozzle arrays, ear-shaped anchoring sections145extend toward the sides. In the anchoring sections145, anchoring holes147open, into which anchoring pins146for mounting the head cover119on the head case118are inserted. In addition, the side wall sections144are connected to a ground line (not shown), which is connected to the printer101. Accordingly, the head cover119is adjusted to have the ground potential.

The exposure window143of the head cover119has a sash shape so as to expose the nozzle arrays116, and the size (internal size) thereof is set to be smaller than the nozzle plate117. Therefore, when the head cover119is mounted on the head case118, the nozzle plate117is exposed from the exposure window143while overlapping a part of the frame section140of the head cover119.

The frame section140is formed in a substantially rectangular frame shape, and has a contact projection148which projects from the frame section140toward the liquid ejecting surface of the nozzle plate17. The contact projection148is brought into contact with the metallic base material portion of the liquid ejecting surface of the nozzle plate117in a state in which the head cover119is mounted on the head case18.

The contact projection148in this embodiment is provided in the inner circumferential edge of the exposure window143of the head cover119.

As shown inFIG. 6A, the contact projection148the front end of which projects toward the liquid ejecting surface from the rear surface of the frame section140to be brought into contact with the nozzle plate117, is provided along the entire inner circumferential edge of the exposure window143. Specifically, the sharp front end of the contact projection148projects by 20 μm from the rear surface of the frame section140toward the nozzle plate117. That is, L1inFIG. 6Ais set to 20 μm. In addition, in a state where the head cover119is mounted on the head case118, a surface pressure applied to the anchoring section145when the anchoring pin146is mounted is applied to the frame section140through the side wall section144. And then, a force, which presses the contact projection148toward the liquid ejecting surface direction of the nozzle plate117, is also applied to the contact projection48. Accordingly, even when the liquid repellent coating layer135having a high insulation property exists on the liquid ejecting surface of the nozzle plate117, the contact projection148passes through the liquid repellent coating layer135so as to be brought into contact with the metallic base material portion of the nozzle plate117. Therefore, the connection can be reliably ensured by the contact projection148, and thus the nozzle plate117can be adjusted to have the ground potential through the head cover119. Accordingly, even though the liquid repellent coating layer135having high liquid repellency is formed on the liquid ejecting surface of the nozzle plate117, an inconsistency, such as an electrostatic breakdown or an erroneous operation of a driving circuit or the like due to static electricity, can be prevented.

Further, according to the present example, the contact projection148is provided over the entire inner circumferential edge of the exposure window143of the head cover119. Therefore, a clearance between the head cover119and the nozzle plate117can be blocked by the contact projection148. Accordingly, although misty ink droplets are slightly ejected from the nozzle orifices, the ink droplets can be prevented from intruding into the head cover119from the exposure window143of the head cover119. In addition, the recording medium, such as a recording paper or the like, can be prevented from being caught in the clearance between the head cover119and the nozzle plate117.

Moreover, the contact projection148may be formed by using a burr which is generated by a pressing process when the exposure window143is formed, If doing so, since the direction where the burr and the contact projection148project can be the same, the contact projection148can be easily formed, without needing a new process.

The contact projection148may be provided on the inner circumferential edge of the positioning hole142aof the head cover119as shown inFIG. 6B.

Specifically, the contact projection148, the front end of which projects toward the liquid ejecting surface of the nozzle plate117from the inner circumferential edge of the positioning hole142ain the frame section40, is provided on the entire inner circumferential edge of the positioning pin142a. Specifically, the ring-shaped front end of the contact projection148projects, for example, by 20 μm from the rear surface of the frame section140toward the nozzle plate117. That is, L2inFIG. 6Bis set to 20 μm. In addition, in a state in which the head cover119is mounted on the head case118, the surface pressure applied to the anchoring section145when the fixing pin146is mounted is applied to the frame section140through the side wall section144. Further, a pressure applied by caulking of the positioning pin141is also applied around the positioning hole142a. Therefore, a force is applied to the contact projection148toward the liquid ejecting surface of the nozzle plate117. Accordingly, even when the liquid repellent coating layer135having a high insulation property exists on the liquid ejecting surface of the nozzle plate117, the contact projection148passes through the liquid repellent coating layer135so as to be brought into contact with the metallic base material portion of the noble plate117, such that the connection can be reliably ensured. Therefore, the nozzle plate117can be adjusted to have the ground potential through the head cover119. For this reason, even though the liquid repellent coating layer135having high liquid repellency is formed on the liquid ejecting surface of the nozzle plate117, the inconsistency, such as the electrostatic breakdown or the erroneous operation of a driving circuit or the like due to the static electricity can be prevented.

Further, according to the present example, since the contact projection148is provided on the inner circumferential edge of the positioning hole42aof the head cover119, in a state where the head cover119is mounted on a head case118, the force is applied toward the liquid ejecting surface, as described above. Accordingly, the contact projection148bites into the nozzle plate117, such that misalignment of the head cover119can be suppressed. Therefore, when the head cover119is mounted, position accuracy when the positioning pin141is inserted for positioning can be maintained after mounting.

The contact projection148in the present example may be formed by using a burr or bulge which is generated by a punching process when the positioning hole142is formed. For example, after a through hole (the positioning hole42a) opens in the head cover119, as shown inFIG. 7A, a punch150awhose end is sharp is pressed into the through hole, such that the contact projection148can be formed in a shape according to the punch150a.

Further, as shown inFIG. 7B, for example, a mold of the contact projection hole148is previously created in a die149which is used for a punching process. When the through hole (the positioning hole142a) opens through the punching process, the positioning hole142aand the contact projection148can be formed at the same time , while the bulge extruded by the punch150bis formed in a shape according to the mold of the die149.

Further, the contact projection148may be provided in both the inner circumferential edge of the exposure window143of the head cover119and the inner circumferential edge of the positioning hole142a.

In a region on the liquid ejecting surface of the nozzle plate117where the contact projection148comes into contact with the liquid ejecting surface of the nozzle plate117, the contact projection148may come into contact with the liquid ejecting surface of the nozzle plate117after the liquid repellent coating layer135is removed in advance by the irradiation of ultraviolet rays. In this case, the contact projection148can be reliably brought into contact with the metallic base material portion of the liquid ejecting surface of the nozzle plate117, regardless of the surface pressure applied to the frame section or the pressure from the positioning pin, in a state where the head cover is mounted.

In this embodiment, the contact projection148is provided on the entire inner circumferential edge of the frame section140. However, the contact projection148may be provided on at least a portion of the inner circumferential edge of the frame section140. In this case, as long as the connection between the contact projection148and the liquid ejecting surface of the nozzle plate117can be ensured, the contact projection148can have any shape.

Next, a second embodiment of the invention will be described. As shown inFIGS. 8 to 10, an ink jet type recording head1is provided with a head case16in which a piezoelectric vibrator14is housed, a flow passage unit26which is fixed to a unit fixing face of the head case16by an adhesive, and a head cover27which covers the flow passage unit26.

The flow passage unit26is a laminated body of a flow passage forming substrate11in which a flow passage space including pressure generating chambers19arranged and an ink reservoir17for storing ink to be supplied to the individual pressure generating chambers19, a nozzle plate10which is laminated on one surface of the flow passage forming substrate11and which has nozzle orifices15to eject ink within the pressure generating chambers19, a vibration plate (sealing plate)12which is laminated on the other surface of the flow passage forming substrate11to seal the flow passage space including the pressure generating chambers19. The flow passage unit26eject ink pressed by the piezoelectric vibrator14from the nozzle orifices15of the nozzle plate10.

On the nozzle plate10, nozzle arrays25are formed, in each of which the plurality of nozzle orifices15are arranged. In this embodiment, six nozzle arrays25are formed to eject different types of ink The nozzle plate10is mainly formed of a conductive material, such as a stainless plate or the like.

In the flow passage forming substrate11, the pressure generating chambers19are arranged to be correspondingly connected to the nozzle orifices15. In addition, the common ink reservoir17, which is connected to the individual pressure generating chambers19through an ink supply passage18so as to store ink to be supplied to the individual pressure generating chambers19, is formed to be disposed along the pressure generating chambers19. The flow passage forming substrate11is formed by etching a monocrystalline silicon substrate.

The vibration plate12is formed of a resin film, such as a polyphenylene sulfide film, on which an island section13formed of a stainless plate or the like is laminated.

The flow passage unit26is constructed by laminating the nozzle plate10on one surface of the flow passage forming substrate11and by laminating the vibration plate12on the other surface thereof such that the island section12is disposed outside. The flow passage forming substrate11, the nozzle plate10, and the vibration plate12are laminated by an adhesive, are heated and held at a predetermined high temperature while being pressed in a vertical direction, and then are cooled down to a room temperature, thereby forming the flow passage unit26.

The head case16, which is formed by injecting thermosetting resin or thermoplastic resin, has a body section24which houses the piezoelectric vibrator14, and a flange section28which is formed in an opposite side to the unit fixing face of the body section24.

The body section24has vertical housing spaces21, in which the piezoelectric vibrators14are housed to correspond to the individual pressure generating chambers19. Six housing spaces21extending along the nozzle arrays25are provided to correspond to the individual nozzle arrays25(inFIG. 10, only one is shown). The piezoelectric vibrator14is a piezoelectric vibrator14in a longitudinal vibration mode, and a back end thereof is fixed to the fixing plate20.

The flange section28is formed on an opposite side to the unit fixing face of the body section24so as to extend outward from an outer circumference of the body section24to be stretched.

Further, in a state in which the vibration plate12of the flow passage unit26is bonded to the unit fixing face of the head case16by an adhesive, a front end face of the piezoelectric vibrator14is fixed to the island section13of the vibration plate12, and the fixing plate20is bonded and fixed to the head case16.

The head cover27is formed by bending a conductive metal plate, such as a stainless plate or the like. The head cover27is mounted on a head body2in which the flow passage unit26is fixed to the head case16, so as to cover the flow passage unit26.

The head cover27is formed in a substantially frame shape so as to cover the outer circumference of the head body2, and has a window31for exposing the nozzle orifices15of the nozzle formation face30. The head cover27includes a cover section32which covers the nozzle formation face30in a peripheral portion of the window31, side face sections33which are bent from the cover section32so as to cover the side faces of the head case16, and screwing sections34which are bent from the side face sections33so as to screw the head cover27.

The head cover27covers both end portions in a direction in which the cover section32is perpendicular to the nozzle arrays25of the nozzle formation face30. The side face sections cover the end portions of the flow passage unit26and the side faces of the head case16. Further, the screwing sections34are screwed by screws35with respect to the flange section28of the head case16.

The screwing sections34are formed on both sides in the direction perpendicular to the nozzle arrays25of the head cover27(a primary scanning direction in which the recording head1is moved by a carriage) and on one side in the direction along the nozzle arrays25(a secondary scanning direction perpendicular to the primary scanning direction). The screwing sections34screw the head cover27at three places.

The screws35screwed to the screwing sections34are configured such that the head cover27is mounted on the head case16, and the head body2is mounted on the carriage (not shown). The screwing sections34formed on both sides in the primary scanning direction are formed in the vicinities of the opposite side to one screwing section formed on one side in the secondary scanning direction, thereby supporting the head body, which is rectangular in plan view, at three points.

In the recording head1having such a configuration, a driving signal generated by a driving circuit23is input to the piezoelectric vibrator14through a flexible circuit board22, such that the piezoelectric vibrator14expands and contracts in a longitudinal direction. With the expansion and contraction of the piezoelectric vibrator14, the island section13of the vibrating body12vibrates, and thus a pressure within the pressure generating chamber19changes. And then, ink within the pressure generating chamber19is ejected as ink droplets from the nozzle orifices15.

The recording head1is mounted on the carriage which reciprocates in a widthwise direction of a recording paper, ejects ink droplets onto the recording paper while the carriage moves, and prints images or characters onto the recording paper in a dot matrix manner.

As shown inFIGS. 11A through 12, in the nozzle plate10, an insulating film37is formed on the nozzle formation face (to be opposed to a recording medium) of a conductive mother material36formed of stainless steel or the like. The thickness of the conductive mother material is not particularly limited, but is set to about 30 to 120 μm in accordance with ejecting characteristics. The thickness of the insulating film37is not particularly limited, but is set to about 0.1 to 1 μm, which is much thinner than the thickness of the conductive mother material36.

The insulating film37is, for example, a glassy film which exhibits water repellency. On the nozzle formation face30of the conductive mother material36, for example, a plasma-polymerized film is formed by plasma-polymerizing a silicon material. And then, a metal-alkoxide molecular film having liquid repellency is formed on the plasma-polymerized film.

As a raw material of the plasma-polymerized film, silicone oil, alkoxysilane, and specifically, dimethylpolysiloxane, are exemplified. As a product, TSF451 (available from GE Toshiba Silicones), SH200 (available from Dow Corning Silicones), or the like can be used. The plasma-polymerized film can be formed through the following process, for example. The plasma-polymerized film can be formed by disposing the nozzle plate10within a chamber, which is aspirated at a predetermined negative pressure, and by purifying argon plasma within the chamber while supplying evaporated silicone as a raw material.

As the metal-alkoxide molecular film, any film having water repellency and oil repellency may be used. Preferably, a metal-alkoxide mono-molecular film having a long-chain polymer group (hereinafter, referred to as long-chain RF group) including fluorine or a metalate mono-molecular film having a liquid repellent group is used. As the metal alkoxide, Ti, Li, Si, Na, K, Mg, Ca, St, Ba, Al, In, Ge, Bi, Fe, Cu, Y, Zr, Ta, or the like, can be used but silicon, titanium, aluminum, zirconium, or the like is generally used. In the present embodiment, a silicon-based product is used. Preferably, alkoxysilane having the long-chain RF group including fluorine or metalate having a liquid repellent group may be used.

As the long-chain RF group whose molecular weight is 1000 or more, perfluoroalkyl chain, perfluopolyether chain, or the like is exemplified. As alkoxysilane having the long-chain RF group, a silane coupling agent having the long-chain RF group or the like is exemplified. As the silane coupling agent having the long-chain RF group which is suitable as a liquid repellent film of the present invention, heptatriaconta fluoroicosyl trimethoxysilane or the like is exemplified, for example. As a product, however, OPTOOL DSX (Trademark, available from Daikin Industries, Ltd.) and KY-130 (Trademark, available from Shin-Etsu Chemical Co., Ltd.) are exemplified. Since a carbon-fluorine group (RF group) has a surface free energy smaller than an alkyl group, when the metal alkoxide contains the RF group, liquid repellency of the liquid repellent film to be formed can be improved, and characteristics, such as chemical resistance, weather resistance, and friction resistance, can be also improved. In addition, as the R F group, a group whose long-chain structure is long can further keep liquid repellency. As the metalate having a liquid repellent group, aluminate, titanate, and the like are exemplified.

The metal-alkoxide molecular film is formed by heating the nozzle plate10on which the plasma-polymerized film is formed in a range of 200 to 400° C. and by dipping into a solution in which metal alkoxide is mixed with a solvent, such as a thinner or the like, such that the concentration thereof is adjusted to, for example, 0.1 weight percent.

Moreover, a water repellent film is not limited to the above-described films, but various films, such as a fluorine resin film or the like, can be applied.

On the nozzle formation face30of the nozzle plate10, an exposure section38is formed, where the insulating film37is removed such that the conductive mother material36is exposed to the nozzle formation face30Through the exposure section38, the head cover27formed of a conductive material and the conductive mother material36of the nozzle plate10are electrically connected to each other.

In this embodiment, the exposure section38is formed as follows. That is, by forming a concave section39in the back face on the opposite side to the nozzle formation face30of the nozzle plate10, a contact projection40is formed where the conductive mother material36projects on the nozzle formation face30of the nozzle plate10. Further, a top region of the contact projection40is formed in the exposure section38where the insulating film37is removed so as to expose the conductive mother material36.

The concave section39and the contact projection40can be formed by performing laser marking on the back face (opposite to the nozzle formation face30) of the nozzle plate10, such that the concave section39on the back face is formed and the contact projection40is formed to be swollen. Alternatively, press molding is performed in which a punch is pressed into the back face of the nozzle plate10, such that the concave section39is formed on the back face and the contact projection40is formed on the nozzle formation face30to be swollen.

The contact projection40of the conductive mother material36is set to have a projection height larger than the thickness of the insulating film37, and thus the top region of the contact projection40projects from the surface of the insulating film37toward the nozzle formation face30, such that the conductive mother material36is exposed to the nozzle formation face30. That is, the thickness of the insulating film37is set to be in a range of about 0.1 to 1 μm, while the projection height of the conductive mother material36of the contact projection40from the nozzle formation face30is set to, for example, about 3 to 6 μm. When the concave section39and the contact projection40are formed by laser marking, if the concave section39and the contact projection40have the same base material quality, the projection height of the contact projection40is changed according to the laser intensity at the time of laser marking. Therefore, control and management can be performed by regulating the laser intensity. In addition, when the contact projection40is formed by press molding, the projection height of the contact projection40can be controlled and managed by regulating a pressing degree of the punch.

As shown inFIGS. 11C and 12, a plurality of contact projections40are formed on the nozzle formation face30in the vicinity of one edge of the nozzle plate10.

As shown inFIG. 13A, the contact projections40are arrayed parallel to the nozzle arrays25on one of both sides in the primary scanning direction.

As shown inFIG. 14, the nozzle plate10is formed by cutting out the plurality of nozzle plates10from one base material plate41. In this embodiment, six nozzle plates10are cut out from one base material plate41by punching with a press. Reference numeral43represents a punching proposed line which serves as a contour line at the time of punching.

Further, when the plurality of nozzle plates10are cut out from one base material plate41in such a manner, the arrangement of the nozzle plates10in the base material plate41is marked as arrangement addresses on the individual nozzle plates10, which can be used to analyze defects of the cut nozzle plate10. In this embodiment, the contact projections40for the electrical connection between the head cover27and the nozzle plate10also serve as the marks of arrangement addresses.

According to the arrangement in the base material plate41, No.1, No.2, No.3, No.4, No.5, and No.6(arrangement addresses) are allocated to the individual nozzle plates10. The arrangement addresses are marked and displayed on the individual nozzle plates10by forming the contact projection40.

As shown inFIG. 13B, the arrangement addresses are marked and displayed on the individual nozzle plates10by the contact projections40, On the nozzle plate10, a plurality of proposed regions42a,42b, and42cfor displaying the arrangement addresses are formed. In each of the proposed regions42a,42b, and42c, one contact projection40is formed.

On both sides of the proposed regions42a,42b, and42c, a start point mark44aand an end point mark44bare formed in which two contact projections40are provided close to each other with no gap. The region which is interposed between the start point mark44aand the end point mark44bis an arrangement address displaying region. In regions outside the start point mark44aand the end point mark44b, the contact projections40are provided in parallel at constant pitches.

The number of proposed regions42a,42b, and42care formed by at least the number of digits in a binary number when the binary number represents the number of nozzle plates10to be cut out from the base material plate41. In this embodiment, since six nozzle plates10are cut out from one base material plate41and the number of digits of ‘110’, which is a binary number of ‘6’, is ‘3’, at least three proposed regions42a,42b, and42care provided. In this embodiment, four or more proposed regions may be provided, and only three of them may be used.

Among three proposed regions42a,42b, and42c, according to whether or not the contact projection40is formed in the proposed region42aclose to the start point mark44a, ‘1’ or ‘0’ of a digit of 1 in the binary number is displayed, according to whether or not the contact projection40is formed in the next proposed region42b, ‘1’ or ‘0’ of a digit of 2 in the binary number is displayed, and according to whether or not the contact projection40is formed in the next proposed region42c, ‘1’ or ‘0’ of a digit of 4 in the binary number is displayed, such that the arrangement address is displayed. Here, in this embodiment, when the contact projection40is formed , ‘1’ is displayed, and, when the contact projection40is not formed, ‘2’ is displayed.

That is, in the nozzle plate10whose arrangement address is ‘No.1’, the contact projection40is formed in the proposed region42aof the digit of 1, not in the proposed region42bof the digit of 2 and in the proposed region42cof the digit of 4, thereby displaying a binary number ‘001’, that is, the arrangement address ‘1’. In the nozzle plate10whose arrangement address is ‘No.2’, the contact projection40is formed in the proposed region42bof the digit of 2, not in the proposed region42aof the digit of 1 and in the proposed region42cof the digit of 4, thereby displaying a binary number ‘010’, that is, the arrangement address ‘2’.

In the nozzle plate10whose arrangement address is ‘No.3’, the contact projections40are formed in the proposed region42aof the digit of 1 and in the proposed region42bof the digit of 2, not in the proposed region42cof the digit of 4, thereby displaying a binary number ‘011’, that is, the arrangement address ‘3’. In the nozzle plate10whose arrangement-address is ‘No.4’, the contact projection40is formed in the proposed region42cof the digit of 4, not in the proposed region42aof the digit of 1 and in the proposed region42bof the digit of 2, thereby displaying a binary number ‘100’, that is, the arrangement address ‘4’.

Similarly, in the nozzle plate10whose arrangement address is ‘No.5’, a binary number ‘101’, that is, the arrangement address ‘5’ is displayed. In the nozzle plate10whose arrangement address is ‘No.6’, a binary number ‘110’, that is, the arrangement address ‘6’ is displayed.

In this embodiment, the plurality of proposed regions42a,42b, and42care provided along the edge of the nozzle plate10. Before the edge, the start point mark44ais disposed on the right side, and the end point mark44bis disposed on the left side. In order from the side close to the start point mark44a, the proposed region42aof the digit of 1, the proposed region42bof the digit of 2, and the proposed region42cof the digit of 4 are sequentially formed.

As such, according to whether or not the contact projection40is formed in each of the plurality of proposed regions42a,42b, and42cof the arrangement address displaying region interposed between the start point mark44aand the end point mark44b, the arrangement address of the nozzle plate10in the base material plate41is displayed.

The nozzle plate10formed in such a manner is used to form the flow passage unit26, thereby forming the recording head1(seeFIGS. 8 to 10).

In this state, the head cover27is electrically connected to a case of the recording apparatus through a contact plate formed on the carriage and a guide bar for guiding the reciprocation of the carriage. Accordingly, the conductive mother material36of the nozzle plate10is grounded through the head cover27.

Next, a method of manufacturing the recording head1of the present invention will be described.

First, a plate material of the conductive mother material36is prepared, and the nozzle orifices15are formed at predetermined positions inside the punching proposed line43by a pressing process or a laser process.

Next, as shown inFIGS. 16A and 16B, the insulating film37is formed on the nozzle formation face30of the base material plate41in which the nozzle orifices15are formed.

Next, as shown inFIGS. 15 and 16C, the concave section39is formed in the back face opposite to the nozzle formation face30of the base material plate41, on which the insulating film37is formed, by laser marking or press molding. The contact projection40is formed to be swollen on the nozzle formation face30to correspond to the concave section39. In this case, the plurality of contact projections40are arranged along the punching proposed line43in one end side parallel to the nozzle arrays25of on one side of both sides in the primary scanning direction in the region, which becomes the nozzle plate10.

Next, as shown inFIG. 16D, the insulating film37in the top region of the contact projection40is removed to expose the conductive mother material36, such that the exposure section38is formed. At this time, the insulating film37may be grinded and removed by performing a grinding process on the nozzle formation face30of the nozzle plate10. Further, the insulating film37may be removed by friction between the head cover27and the top portion of the contact projection40when the head cover27is screwed, in particular, without using the removal process of the insulating film37, In a process of assembling the head cover27, when the exposure section38is formed in the contact projection40, the electrical connection between the exposure section38and the head cover27may be ensured.

In addition, as described above, the start point mark44aand the end point mark44bare formed in each of the nozzle plates10by laser marking, and simultaneously, in the region outside the start point mark44aand the end point mark44b, the contact projections40are formed at constant pitches.

Further, as described above, the arrangement address of each nozzle plate is marked according to whether or not the contact projection40is formed in each of the plurality (three in this embodiment) of proposed regions42a,42b, and42cwhich are provided between the start point mark44aand the end point mark44b.

Further, the punching proposed line43is cut so as to form the contour of the nozzle plate10, such that the nozzle plate10shown inFIG. 13Ais formed.

Next, as shown inFIG. 17A, the nozzle plate10formed in such a manner is laminated and bonded to the flow passage forming substrate11and the vibrating body12by the adhesive, thereby forming the flow passage unit26. At this time, since the above-described contact projection40is formed on the nozzle formation face30of the nozzle plate10, a cushion sheet46is disposed on the nozzle formation face30and then a pressure is applied by pressing with a press jig47through cushion sheet46, such that bonding is performed.

Next, as shown inFIG. 17B, the flow passage unit26formed in such a manner is bonded to the head case16by the adhesive, thereby forming the head body2. At this time, the cushion sheet46is also disposed on the nozzle formation face30and a pressure is applied by pressing with the press jig47through the cushion sheet46, such that bonding is performed.

As the cushion seat46, for example, a fluorine resin sheet can be used. Since the projection height of the contact projection40is set in a range of about 3 to 6μm, the contact projection40can be sufficiently absorbed by the fluorine resin sheet, such that bonding is performed without unevenness.

As shown inFIG. 18A, the head cover27is mounted on the head body2configured as described the above. That is, the head cover27is put on the head body2such that the nozzle orifices15of the nozzle formation face30are exposed from the window31, and the three screwing sections34are screwed to the flange section28by the screws35. And then, the head cover27is mounted on the head body2. At this time, when the head cover27is screwed so as to cover the nozzle formation face30and the head case16, the exposure section38of the top portion of the contact projection40is brought into contact with the head cover27and the contact projection40is electrically connected to the head cover27.

At this time, as shown inFIG. 16C, the head cover27is mounted in a state in which the top portion of the contact projection40of the nozzle plate10is covered with the insulating film37. By screwing at the time of mounting, the cover section32of the head cover27scrapes against the top region of the contact projection40. And then, as shown inFIG. 16D, the insulating film37in the scraped region is peeled off, and the conductive mother material36is exposed so as to form the exposure section38. As a result, the head cover27and the conductive mother material36of the nozzle plate10are electrically connected to each other.

By screwing the screwing sections34, a force, which presses the cover section32of the head cover27onto the nozzle formation face30, acts on the head cover27. Therefore, when the contact projection40is formed in the region close to the screwing section34of the head cover27on the nozzle formation face30of the nozzle plate10, as shown inFIG. 19, the electrical connection between the contact projection40and the head cover27can be reliably ensured. In this embodiment, since the screwing sections34are formed on both sides in the primary scanning direction of the head body2, the contact projections40are arranged in the region close to one end in the primary scanning direction of the nozzle plate10.

In the three screwing sections34, a clockwise torque acts when a normal right-handed screw is screwed. Therefore, on the screwing section34aon the right side ofFIG. 18Aamong the three screwing sections34, the force, which presses the cover section32onto the nozzle formation face30through the side face sections33, acts due to a tightening torque when the head cover27is screwed (seeFIGS. 18B and 18C). Therefore, as shown inFIG. 19, for the sake of the reliable electrical connection, the contact projection40may be formed in the region where the cover section32is pressed onto the nozzle formation face30through the side face sections33by the tightening torque when the head cover27is screwed. In this case, the region is a region C which is surrounded by a dashed line in Fig,19.

With the above configurations, the conductive mother material36of the nozzle plate10and the head cover27are reliably connected to each other in the top region of the contact projection40formed on the nozzle formation face30. Therefore, in the nozzle plate10on which the insulating film37is formed of a water repellent film or a hydrophilic film, static electricity flying from a paper to the nozzle plate10or the charges of the nozzle plate10can be effectively released through the head cover27, and ejecting defects caused by dirt on the nozzle formation face30or a damage of an IC can be effectively prevented.

Further, the contact projection40of the conductive mother material36is set to have a projection height larger than the thickness of the insulating film37, and thus the exposure section38is formed at a position which projects from the surface of the insulating film37. Therefore, the electrical connection to the head cover27can be reliably ensured.

Further, when the concave section39and the contact projection40are formed by laser marking with respect to the back face of the nozzle plate10, by forming the concave section39on the back face of the nozzle plate10through laser marking, the nozzle formation face30may be swollen, thereby forming the contact projection40. Therefore, the contact projection40can be easily formed, manufacturing costs can be prevented from being unnecessarily increased, and position accuracy when the contact projection40is formed can be also improved. As a result, reliability can be ensured.

Further, when the concave section39and the contact projection40are formed by press molding with respect to the back face of the nozzle plate10, by forming the concave section39on the back face of the nozzle plate10through press molding, the nozzle formation face30may be swollen, thereby forming the contact projection40. Therefore, the contact projection40can be easily formed, manufacturing costs can be prevented from being unnecessarily increased, and position accuracy when the contact projection40is formed can be improved. As a result, reliability can be ensured.

Further, the contact projection40is formed in the region along the end side of the nozzle plate10, and thus the electrical connection to with the head cover27can be ensured in the region along the end side of the nozzle plate10. Therefore, an effective area of the nozzle formation face30to be exposed from the window31of the head cover27is not made narrower than is necessary, such that the head itself can be prevented from being enlarged.

Further, since the plurality of contact projections40are formed along the end side of the nozzle plate10, the electrical connection with the head cover27can be ensured by just one of the plurality of contact projections40. Therefore, a possibility of occurrence of troubles due to connection defects can be significantly reduced, such that reliability can be ensured.

Further, the head cover27includes the cover section32which covers the nozzle formation face30, the side face sections33which are bent from the cover section32so as to cover the side faces of the head case16, and the screwing sections34which are bent from the side face sections33so as to screw the head cover27. When the head cover27is screwed to cover the nozzle formation face30and the head case16, the contact projection40and the head cover27is electrically connected to each other. Therefore, by screwing the head cover27, the force is applied in a direction in which the cover section32of the head cover27is pressed onto the nozzle formation face30. As a result, a force is easily applied in a direction in which the cover section32is pressed onto the contact projection40, such that the connection can be reliably ensured and reliability can be improved.

Further, the contact projection40is formed in the region close to the screwing section34of the head cover27in the nozzle formation face30of the nozzle plate10. Accordingly, by forming the contact projection40in the region close to the screwing section34, the force can be easily applied in the direction in which the cover section32is pressed onto the contact projection40, such that the connection can be ensured reliably and reliability can be improved.

Further, the contact projection40is formed in the region where the cover section32is pressed onto the nozzle formation face30through the side face sections33by the tightening torque when the head cover27is screwed. Therefore, the contact projection40is formed in the region where the force is applied in the direction in which the cover section32of the head cover27is pressed onto the nozzle formation face30, by screwing the head cover27. As a result, the connection can be ensured reliably and reliability can be improved.

Further, when the plurality of nozzle plates10are cut out from the base material plate41, the contact projections40are formed in the proposed regions42a,42b, and42cby at least the number of digits in the binary number when the binary number represents the number of nozzle plates10to be cut out from the base material plate41. Therefore, in order to analyze defects of the plurality of the nozzle plates10cut out from the base material plate41, the contact projections40can be used for marking the arrangement addresses of the nozzle plates10in the base material plate41. Further, a process of forming only the contact projections40does not need to be provided, and thus it is very advantageous in view of process efficiency or costs.

Further, according to whether or not the contact projection40is formed in each of the proposed regions42a,42b, and42c, the arrangement address of the nozzle plate10in the base material plate41is displayed. Therefore, when the contact projection40is used for marking the arrangement address of the nozzle plate10in the base material late41, a process of forming only the contact projection40does not need to be provided, and thus it is very advantageous in view of process efficiency or costs.

Further, the insulating film37is a water repellent film, and thus a glassy or ceramic film having an excellent water repellent effect can be applied. Therefore, cleanliness of the nozzle formation face after wiping can be improved, and dirt or ejecting defects on an object surface caused by dirt of the nozzle formation face can be safely reduced.

Further, the conductive mother material36of the nozzle plate10is grounded through the head cover27. Therefore, the static electricity transferred from the paper to the nozzle plate10or the charges of the nozzle plate10can be effectively released through the head cover27. As a result, ejecting defects or the damage of the IC caused by dirt on the nozzle formation face30can be effectively prevented.

FIG. 20shows a third embodiment of the invention. Components similar to those in the second embodiment will be designated by the same reference numerals and repetitive explanations for those will be omitted. In this embodiment, arrays of the contact projections40are formed in regions close to both edges of the nozzle plate10in the primary scanning direction.

In this embodiment, the exposure section38is not formed in the above-described method in which the insulating film37is peeled off by the friction between the contact projection40and the head cover27when the head cover27is mounted. Alternatively, the insulating film37in the top region of the contact projection40is removed by grinding the nozzle formation face30of the nozzle plate10, thereby forming the exposure section38.

That is, the exposure section38may be formed by grinding the nozzle formation face of the nozzle plate10so as to remove the insulating film37in the top region of the contact projection40in a state of the flow passage unit26into which the nozzle plate10having the top portion of the contact projection40covered with the insulating film37is assembled or by grinding the nozzle formation face of the nozzle plate10so as to remove the insulating film37in the top region of the contact projection40in a state of the head body2in which the flow passage unit26is fixed to the head case16.

In this case, the contact projections40are arranged in the regions close to both edges in the primary scanning direction of the nozzle plate10, such that the posture of the flow passage unit26or the head body2during grinding is stabilized and a damage of the nozzle formation face30at the time of grinding is prevented. As to any other points, the same advantages as those in the second embodiment can be obtained.

Next, a fourth embodiment of the invention will be described. Similar components to those in the second embodiment will be designated by the same reference numerals and repetitive explanations for those will be omitted.

In this embodiment, an exposure section58shown inFIG. 21Ais formed as follows. By performing laser marking with respect to the nozzle formation face30of the nozzle plate10, as shown inFIGS. 21B and 21C, a concave section59is formed on the nozzle formation face30of the conductive mother material36, and the peripheral portion of the concave section59is swollen by heat or stress generated at the time of laser marking. And then, a contact projection60, in which the conductive mother material36projects on the nozzle formation face30of the nozzle plate10, is formed to be swollen, and the top region of the contact projection60is formed in the exposure section58.

The contact projection60of the conductive mother material36is set to have a projection height larger than the thickness of the insulating film37, and thus the top region of the contact projection60projects from the surface of the insulating film37on the nozzle formation face30, such that the conductive mother material36is exposed to the nozzle formation face30. That is, the thickness of the insulating film37is set in a range of bout 0.1 to 1 μm. In contrast, the projection height of the contact projection60from the nozzle formation face30of the conductive mother material36is set in a range of about 3 to 6 μm. If the concave section59and the projection section60have the same mother material quality, the projection height of the contact projection60is changed according to the laser intensity at the time of laser marking. Therefore, control and management can be performed by adjusting the laser intensity.

As shown inFIGS. 21C and 22, the contact projection60is formed on the nozzle formation face30in the vicinity of the edge of the nozzle plate10. The groove-shaped concave section59formed by laser marking opens in the end portion of the nozzle plate10, and the substantially U-shaped contact projection60is formed around the concave section59.

Specifically, as shown inFIGS. 23A and 23B, the insulating film37is formed on the nozzle formation face30of the base material plate41in which the nozzle orifices15are formed.

Next, as shown inFIG. 23C, laser marking is performed on the nozzle formation face30of the base material plate41on which the insulating film37is formed, thereby forming laser marks45. At this time, laser marking is performed so as to form the laser mark45in a direction perpendicular to the nozzle arrays25, crossing the die-cutting proposed line34, in one end side parallel to the nozzle arrays25on one side of both ends in the primary scanning direction of a region, which becomes the nozzle plate10.

The laser marks45are made by forming the concave section59in the nozzle formation face30of the conductive mother material36. The peripheral portion of the concave section59is swollen by heat or stress generated at the time of laser marking, and thus the contact projection60, in which the conductive mother material36projects on the nozzle formation face30of the nozzle plate10, is formed to be swollen, such that the exposure section58is formed in the top region of the contact projection60.

As described above, the start point mark44aand the end point mark44bare formed in each nozzle plate10by laser marking, and the laser marks45are formed at constant pitches outside the start point mark44aand the end point mark44b.

As described above, the arrangement address of each nozzle plate is marked and displayed, according to whether or not the laser mark45is formed in each of the plurality (three in this embodiment) of proposed regions42a,42b, and42cwhich are provided between the start point mark44aand the end point mark44b.

The outline of the nozzle plate10is formed by punching the punching proposed line43, and thus the nozzle plate10is formed. At this time, punching is performed such that the laser mark45is laterally cut, and thus the contact projection60is formed from the nozzle formation face30of the nozzle plate10up to the edge. The contact projection60has a substantially U shape.

With the above configurations, the concave section59is formed on the nozzle formation face30of the nozzle plate10by laser marking, and the peripheral portion of the concave section59is swollen, thereby forming the contact projection60. Therefore, the contact projection60can be easily formed, manufacturing costs can be prevented from being unnecessarily increased, and position accuracy when the contact projection60is formed can be also improved. As a result, reliability can be ensured. As to any other points, the same advantages as those in the second embodiment can be obtained.

In this embodiment, arrays of the contact projections40may formed in regions close to both edges of the nozzle plate10in the primary scanning direction, as in the third embodiment.

In the above embodiments, the insulating film37is a water repellent film. However, various types of insulating films37, such as a hydrophobic film or the like, may be applied, as long as the film has characteristics suitable for the nozzle formation face30of the nozzle plate10.

In the above embodiments, a plurality of nozzle plates10are cut out from the base material plate41by pressing. However, various methods, other than pressing, such as laser cutting and the like, may be used.

In the above embodiments, the piezoelectric vibrator14is used as the pressure generating element. However, a Bubble Jet (Registered Trademark) type ink jet recording head in which liquid within a pressure generating chamber is heated to generate bubbles may be used.