(19)
(11)EP 3 482 958 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.11.2020 Bulletin 2020/45

(21)Application number: 18206312.3

(22)Date of filing:  14.11.2018
(51)International Patent Classification (IPC): 
B41J 2/16(2006.01)
B41J 2/14(2006.01)

(54)

JET HOLE PLATE, LIQUID JET HEAD, LIQUID JET RECORDING APPARATUS, AND METHOD FOR MANUFACTURING JET HOLE PLATE

STRAHLLOCHPLATTE, FLÜSSIGKEITSSTRAHLKOPF, FLÜSSIGKEITSSTRAHLAUFZEICHNUNGSVORRICHTUNG UND VERFAHREN ZUR HERSTELLUNG DER STRAHLLOCHPLATTE

PLAQUE À TROU DE JET, TÊTE À JET LIQUIDE, APPAREIL D'ENREGISTREMENT À JET LIQUIDE ET PROCÉDÉ DE FABRICATION D'UNE PLAQUE À TROU DE JET


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 14.11.2017 JP 2017218696

(43)Date of publication of application:
15.05.2019 Bulletin 2019/20

(73)Proprietor: SII Printek Inc
Chiba-shi Chiba 261-8507 (JP)

(72)Inventors:
  • HIRATA, Masakazu
    Chiba-shi, Chiba 261-8507 (JP)
  • TAKANO, Kenji
    Chiba-shi, Chiba 261-8507 (JP)
  • SODETAI, Tomoki
    Chiba-shi, Chiba 261-8507 (JP)

(74)Representative: Miller Sturt Kenyon 
9 John Street
London WC1N 2ES
London WC1N 2ES (GB)


(56)References cited: : 
EP-A1- 1 997 636
JP-A- 2004 255 696
US-A1- 2014 055 527
JP-A- H05 155 028
US-A1- 2010 053 269
US-A1- 2016 207 311
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the Invention



    [0001] The present disclosure relates to a jet hole plate, a liquid jet head, a liquid jet recording apparatus, and a method for manufacturing a jet hole plate.

    2. Background Art



    [0002] A liquid jet recording apparatus equipped with a liquid jet head is in wide use. A liquid jet head includes a plurality of laminated plates including a jet hole plate having formed therein large numbers of jet holes, and is configured to eject liquid, specifically, ink, against a target recording medium through the jet holes.

    [0003] Such a jet hole plate is formed by, for example, press working of a metal substrate (see, for example, JP-A-10-226070, and JP-A-2004-255696).

    [0004] US 2010/053269 A1 discloses a liquid ejection head that includes a nozzle formation member having a liquid repellent layer disposed on a droplet ejection face of a nozzle substrate in which one or more nozzle orifices is formed to eject droplets. The liquid repellent layer includes a first sub-layer and a second sub-layer. The first sub-layer contains a higher proportion of low-molecular-weight molecules than the second sub-layer. The second sub-layer contains a higher proportion of high-molecular-weight molecules than the first sub-layer. Both the first sub-layer and the second sub-layer are exposed on a surface of the nozzle formation member.

    [0005] JPH 05 155028 A discloses an ink jet head, and more particularly the nozzle formation in an ink jet print head. The ink jet head includes that the inner surface of a nozzle provided on a nozzle plate is rough and the surface (the outer lateral surface of nozzle) is smooth.

    [0006] US 2016/207311 A1 discloses a liquid discharging head that includes a nozzle plate including a nozzle substrate having a plurality of nozzle holes to discharge a liquid therethrough and a plurality of dimples on the discharging surface of the nozzle substrate to hold a liquid repellent material inside the plurality of dimples in a flowable manner. A liquid repellency film formed by the liquid repellent material on the discharging surface of the nozzle substrate.

    [0007] Documents US 2014/055527 A1, JP 2004 255696 A and EP 1,997,636 A1 also relate to the background of the present disclosure.

    SUMMARY OF THE INVENTION



    [0008] There is a common demand for a long-lasting jet hole plate. It is accordingly desirable to provide a jet hole plate, a liquid jet head, a liquid jet recording apparatus, and a method for manufacturing such a jet hole plate that can achieve a long life.

    [0009] According to a first aspect of the invention there is provided a jet hole plate according to claim 1.

    [0010] According to a second aspect of the invention there is provided a liquid jet head according to claim 6.

    [0011] According to a third aspect of the invention there is provided a liquid jet recording apparatus according to claim 7.

    [0012] According to a fourth aspect of the invention there is provided a method for manufacturing a jet hole plate according to claim 8.

    [0013] The jet hole plate, the liquid jet head, the liquid jet recording apparatus, and the method for manufacturing a jet hole plate according to the aspects of the present disclosure can achieve a long life.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0014] Examples and a preferred embodiment of the present invention will now be described I with reference to the accompanying drawings, in which:

    FIG. 1 is a perspective view schematically representing an example of a structure of a liquid jet recording apparatus according to an example of the present disclosure.

    FIG. 2 schematically represents an exemplary detailed structure of a circulation mechanism and other members shown in FIG. 1.

    FIG. 3 is an exploded perspective view representing an exemplary structure of a liquid jet head of FIG. 2 in detail.

    FIG. 4 schematically shows a bottom view of the exemplary structure of the liquid jet head, without a nozzle plate shown in FIG. 3.

    FIG. 5 is a schematic diagram showing a partial cross section of the exemplary structure at line V-V of FIG. 4.

    FIG. 6 is a partially enlarged schematic bottom view of the nozzle plate shown in FIG. 3.

    FIG. 7 is a cross sectional view schematically representing an exemplary structure at line VII-VII of FIG. 6.

    FIG. 8 is a partially enlarged schematic bottom view of the nozzle plate without a water-repellent film shown in FIG. 6.

    FIG. 9 is a diagram representing an exemplary procedure of manufacturing the nozzle plate of an example.

    FIG. 10A is a cross sectional view representing an example of a manufacturing step of the nozzle plate according to an example.

    FIG. 10B is a cross sectional view representing an example of a manufacturing step after FIG. 10A.

    FIG. 10C is a cross sectional view representing an example of a manufacturing step after FIG. 10B.

    FIG. 10D is a cross sectional view representing an example of a manufacturing step after FIG. 10C.

    FIG. 11 is a partially magnified schematic bottom view of a nozzle plate according to a preferred embodiment according to appended claims.

    FIG. 12 is a partially magnified schematic bottom view of the nozzle plate without a water-repellent film shown in FIG. 11.

    FIG. 13 is a cross sectional view representing an example of a manufacturing step of the nozzle plate shown in FIG. 11.

    FIG. 14 is a schematic cross sectional view representing an exemplary structure of a nozzle plate according to a variation.


    DESCRIPTION OF THE EXAMPLES AND THE PREFERRED EMBODIMENT



    [0015] An example of the present disclosure is described below, with reference to the accompanying drawings. Descriptions are given in the following order.
    1. 1. Example (Nozzle Plate, Inkjet Head, Printer, Method for Manufacturing Nozzle Plate)
    2. 2. Variations

    1. Example


    Overall Configuration of Printer 1



    [0016] FIG. 1 is a perspective view schematically representing an example of a structure of a printer 1 as a liquid jet recording apparatus according to an example of the present disclosure. The printer 1 is an inkjet printer that records (prints) an image, texts, and the like on recording paper P (target recording medium), using an ink 9 (described later). The printer 1 is also an ink-circulating inkjet printer that circulates the ink 9 through a predetermined channel, as will be described later in detail.

    [0017] As illustrated in FIG. 1, the printer 1 includes a pair of transport mechanisms 2a and 2b, ink tanks 3, inkjet heads 4, a circulation mechanism 5, and a scan mechanism 6. These members are housed in a housing 10 of a predetermined shape. The drawings referred to in the descriptions of the specification are appropriately scaled to show members in sizes that are easily recognizable. The printer 1 corresponds to a specific example of a liquid jet recording apparatus of the present disclosure. The inkjet heads 4 (inkjet heads 4Y, 4M, 4C, and 4B; described later) correspond to a specific example of a liquid jet head of the present disclosure.

    Transport Mechanisms 2a and 2b



    [0018] The transport mechanisms 2a and 2b, as shown in FIG. 1, are mechanisms that transport recording paper P along a transport direction d (X-axis direction). The transport mechanisms 2a and 2b each include a grid roller 21, a pinch roller 22, and a drive mechanism (not illustrated). The grid rollers 21 and the pinch rollers 22 extend along the Y-axis direction (width direction of recording paper P), respectively. The drive mechanisms rotate the grid rollers 21 about the roller axis (within a Z-X plane), and are configured by using, for example, a motor.

    Ink Tanks 3



    [0019] The ink tanks 3 store the ink 9 (liquid) to be supplied to the inkjet heads 4. That is, the ink tanks 3 are storages for ink 9. In this example, as shown in FIG. 1, the ink tanks 3 are four separate tanks storing inks 9 of four different colors: yellow (Y), magenta (M), cyan (C), and black (B). Specifically, the ink tanks 3 are an ink tank 3Y storing a yellow ink 9, an ink tank 3M storing a magenta ink 9, an ink tank 3C storing a cyan ink 9, and an ink tank 3B storing a black ink 9. The ink tanks 3Y, 3M, 3C, and 3B are disposed side by side in the housing 10 along X-axis direction. The ink tanks 3Y, 3M, 3C, and 3B have the same configuration, except for the color of the ink 9 stored therein, and accordingly will be collectively referred to as ink tank 3.

    Inkjet Heads 4



    [0020] The inkjet heads 4 record an image, texts, and the like by jetting (ejecting) the ink 9 against recording paper P in the form of droplets through a plurality of nozzle holes (nozzle holes H1 and H2; described later). In this example, as shown in FIG. 1, the inkjet heads 4 are four separate inkjet heads that jet the inks 9 of four different colors stored in the ink tanks 3Y, 3M, 3C, and 3B. That is, the inkjet heads 4 are the inkjet head 4Y for jetting the yellow ink 9, the inkjet head 4M for jetting the magenta ink 9, the inkjet head 4C for jetting the cyan ink 9, and the inkjet head 4B for jetting the black ink 9. The inkjet heads 4Y, 4M, 4C, and 4B are disposed side by side in the housing 10 along Y-axis direction.

    [0021] The inkjet heads 4Y, 4M, 4C, and 4B have the same configuration, except for the color of the ink 9, and accordingly will be collectively referred to as inkjet head 4. The configuration of the inkjet heads 4 will be described later in greater detail (FIGS. 3 to 5).

    Circulation Mechanism 5



    [0022] The circulation mechanism 5 is a mechanism for circulating the ink 9 between the ink tank 3 and the inkjet head 4. FIG. 2 schematically represents an exemplary structure of the circulation mechanism 5, together with the ink tank 3 and the inkjet head 4. The solid arrow in FIG. 2 indicates the direction of circulation of the ink 9. As shown in FIG. 2, the circulation mechanism 5 includes a predetermined channel (circulation channel 50), and a pair of delivery pumps 52a and 52b for circulating the ink 9.

    [0023] The circulation channel 50 is a channel through which the ink 9 circulates between the inkjet head 4 and outside of the inkjet head 4 (inside the ink tank 3). The circulation channel 50 has a channel 50a that connects the ink tank 3 to the inkjet head 4, and a channel 50b that connects the inkjet head 4 to the ink tank 3. In other words, the channel 50a represents a channel through which the ink 9 travels from the ink tank 3 to the inkjet head 4, and the channel 50b is a channel through which the ink 9 travels from the inkjet head 4 to the ink tank 3.

    [0024] The delivery pump 52a is disposed between the ink tank 3 and the inkjet head 4 on the channel 50a. The delivery pump 52a is a pump for delivering the stored ink 9 in the ink tank 3 to the inkjet head 4 via the channel 50a. The delivery pump 52b is disposed between the inkjet head 4 and the ink tank 3 on the channel 50b. The delivery pump 52b is a pump for delivering the stored ink 9 in the inkjet head 4 to the ink tank 3 through the channel 50b.

    Scan Mechanism 6



    [0025] The scan mechanism 6 is a mechanism for scanning the inkjet head 4 along the width direction (Y-axis direction) of recording paper P. As illustrated in FIG. 1, the scan mechanism 6 includes a pair of guide rails 61a and 61b extending along the Y-axis direction, a carriage 62 movably supported on the guide rails 61a and 61b, and a drive mechanism 63 for moving the carriage 62 along the Y-axis direction. The drive mechanism 63 includes a pair of pulleys 631a and 631b disposed between the guide rails 61a and 61b, an endless belt 632 suspended between the pulleys 631a and 631b, and a drive motor 633 for driving and rotating the pulley 631a.

    [0026] The pulleys 631a and 631b are disposed in regions corresponding to end portions of the guide rails 61a and 61b, respectively, along the Y-axis direction. The carriage 62 is joined to the endless belt 632. The inkjet heads 4Y, 4M, 4C, and 4B are disposed side by side on the carriage 62, along the Y-axis direction. The scan mechanism 6, together with the transport mechanisms 2a and 2b, constitutes a moving mechanism for moving the inkjet heads 4 and the recording paper P relative to each other.

    Detailed Configuration of Inkjet Head 4



    [0027] The following specifically describes an exemplary structure of the inkjet head 4, with reference to FIGS. 1 and 2, and FIGS. 3 to 5. FIG. 3 is an exploded perspective view showing an exemplary structure of the inkjet head 4 in detail. FIG. 4 schematically shows a bottom view (X-Y bottom view) of the exemplary structure of the inkjet head 4, without a nozzle plate 41 (described later) shown in FIG. 3. FIG. 5 is a schematic diagram showing a partial cross section (Z-X cross section) of the inkjet head 4 taken at line V-V of FIG. 4.

    [0028] The inkjet head 4 of the present example is what is generally called a side shoot-type inkjet head, and ejects the ink 9 from a central portion in the direction of extension (Y-axis direction) of a plurality of channels (channels C1 and C2; described later). The inkjet head 4 is also a circulatory inkjet head, allowing the ink 9 to circulate to and from the ink tank 3 with the use of the circulation mechanism 5 (circulation channel 50).

    [0029] As illustrated in FIG. 3, the inkjet head 4 mainly includes the nozzle plate 41 (jet hole plate), an actuator plate 42, and a cover plate 43. The nozzle plate 41, the actuator plate 42, and the cover plate 43 are bonded to each other using, for example, an adhesive, and are laminated in Z-axis direction, in this order. In the following, the "top" of the inkjet head 4 is on the side of the cover plate 43, and the "bottom" of the inkjet head 4 is on the side the nozzle plate 41, relative to Z-axis direction. The nozzle plate 41 corresponds to a specific example of a jet hole plate of the present disclosure.

    Nozzle Plate 41



    [0030] The nozzle plate 41 is a plate used for the inkjet head 4. The nozzle plate 41 has a metal substrate 410 having a thickness of, for example, about 50 µm, and is bonded to the bottom surface of the actuator plate 42, as shown in FIG. 3. The metal substrate 410 used for the nozzle plate 41 is, for example, a stainless steel such as SUS316L and SUS304. As illustrated in FIGS. 3 and 4, the nozzle plate 41 (metal substrate 410) has two rows of nozzles (nozzle rows 411 and 412) extending along the X-axis direction. The nozzle rows 411 and 412 are disposed by being separated from each other in Y-axis direction by a predetermined distance. That is, the inkjet head 4 of the present example is a two-row inkjet head. A method for manufacturing the nozzle plate 41 as a jet hole plate according to an example of the present disclosure will be described later in detail.

    [0031] The nozzle row 411 has the plurality of nozzle holes (jet holes) H1 that are disposed in a straight line by being separated from each other in the X-axis direction by a predetermined distance. The nozzle holes H1 penetrate through the nozzle plate 41 in the thickness direction (Z-axis direction), and are in communication with, for example, ejection channels C1e of the actuator plate 42 (described later), as shown in FIG. 5. Specifically, as illustrated in FIG. 4, the nozzle holes H1 are formed in a line, and correspond in position to a central portion of the ejection channels C1e relative to the Y-axis direction. The pitch of the nozzle holes H1 along the X-axis direction is the same as the pitch of the ejection channels C1e along the X-axis direction. The ink 9 supplied through ejection channels C1e is ejected (jetted) out of the nozzle holes H1 of the nozzle row 411, as will be described later in detail.

    [0032] As with the case of the nozzle row 411, the nozzle row 412 has the plurality of nozzle holes (jet holes) H2 that are disposed in a straight line by being separated from each other in the X-axis direction by a predetermined distance. The nozzle holes H2 penetrate through the nozzle plate 41 in thickness direction, and are in communication with, for example, ejection channels C2e of the actuator plate 42 (described later). Specifically, as illustrated in FIG. 4, the nozzle holes H2 are formed in a line, and correspond in position to a central portion of the ejection channels C2e relative to the Y-axis direction. The pitch of the nozzle holes H2 along the X-axis direction is the same as the pitch of the ejection channels C2e along the X-axis direction. The ink 9 supplied through the ejection channels C2e is ejected out of the nozzle holes H2 of the nozzle row 412, as will be described later in detail.

    [0033] FIG. 6 is a partially enlarged view of an exemplary structure (X-Y plane exemplary structure) of the bottom surface of the nozzle plate 41. FIG. 7 is a cross sectional view schematically representing an exemplary structure (Y-Z cross section exemplary structure), taken at line VII-VII of FIG. 6. FIG. 8 is a partially enlarged view of the exemplary structure (X-Y plane exemplary structure) of the bottom surface of the nozzle plate 41, without a liquid repellent film 413 (described later) shown in FIG. 6.

    [0034] The nozzle plate 41 has the metal substrate 410 having the plurality of nozzle holes H1, and the plurality of nozzle holes H2. The metal substrate 410 has an outlet-side principal surface 410B having outlets Ha for the nozzle holes H1 and H2, and an inlet-side principal surface 410A having inlets Hb, largerthan the outlets Ha, provided for the nozzle holes H1 and H2. The nozzle holes H1 and H2 are tapered through holes of gradually decreasing diameter toward the bottom. The outlet-side principal surface 410B has a surface roughness (arithmetic mean roughness Ra) that is smaller in an outlet edge region Ea of the nozzle holes H1 and H2 than in a surrounding region Eb around the outlet edge region Ea (formula (1)). The surface roughness (arithmetic mean roughness Ra) is based on ISO 4287-1997 standards, and is measured with, for example, a non-contact measurement device such as a laser microscope and a white light interferometer, and a contact measurement device such as a stylus surface roughness meter.

    Ra1: Surface roughness (arithmetic mean roughness Ra) of outlet edge region Ea

    Ra2: Surface roughness (arithmetic mean roughness Ra) of surrounding region Eb



    [0035] The outlet edge region Ea includes at least a region of the metal substrate 410 opposite the inlet Hb in a thickness direction of the metal substrate 410. The surrounding region Eb is the region of the outlet-side principal surface 410B excluding the outlet edge region Ea. The outlet edge region Ea has, for example, a circular ring shape. The shape of the outlet edge region Ea is not limited to a circular ring shape. The outlet edge region Ea may have, for example, an ellipsoidal ring shape or a square ring shape. In the case of an outlet edge region Ea having a circular ring shape, the outer diameter D1 of the outlet edge region Ea is smaller than the pitch D2 of the nozzle holes H1 and H2. That is, the outlet edge regions Ea are separated from each other on the outlet-side principal surface 410B.

    [0036] The outlet edge region Ea is a polished surface formed by mechanical polishing. The outlet edge region Ea is, for example, a region polished by tape polishing. When the metal substrate 410 is configured from a stainless steel such as SUS316L, the outlet edge region Ea has a surface roughness Ra1 of, for example, 0.001 µm to 0.1 µm. The surrounding region Eb is an unpolished region, or a more coarsely polished region compared to the outlet edge region Ea. When the metal substrate 410 is configured from a stainless steel such as SUS316L, the surrounding region Eb has a surface roughness Ra2 of, for example, 0.2 µm to 1.0 µm.

    [0037] The nozzle plate 41 also includes a liquid repellent film 413 that directly contacts the outlet-side principal surface 410B. The liquid repellent film 413 is formed on the outlet-side principal surface 410B except in the outlet edge regions Ea, and covers the surrounding regions Eb either in part or as a whole. For example, the liquid repellent film 413 is formed in contact with the surrounding regions Eb, either in part or as a whole. The liquid repellent film 413 has an opening 413H in a position opposite the outlet edge region Ea and the outlet Ha. The opening 413H surrounds each outlet edge region Ea on the outlet-side principal surface 410B. The liquid repellent film 413 is useful for effectively removing ink 9 from the outlet-side principal surface 410B when wiping the outlet-side principal surface 410B for cleaning. The liquid repellent film 413 may be a fluororesin, for example, such as PTFE (polytetrafluoroethylene), PFEP (a tetrafluoroethylene-hexafluoropropylene copolymer), PFA (a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer), and FEP (an ethylene tetrafluoride-propylene hexafluoride copolymer). Aside from fluororesins, for example, a fluorinated silane coupling agent or a fluorine-containing acrylic resin may be used for the liquid repellent film 413.

    Actuator Plate 42



    [0038] The actuator plate 42 is a plate configured from, for example, a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 42 is what is generally called a chevron-type actuator, which is formed by laminating two piezoelectric substrates of different polarization directions in Z direction. The actuator plate 42 may be a so-called cantilever-type actuator formed of a single piezoelectric substrate of a unidirectional polarization direction along the thickness direction (Z-axis direction). As shown in FIGS. 3 and 4, the actuator plate 42 has two rows of channels (channel rows 421 and 422) extending along X-axis direction. The channel rows 421 and 422 are disposed by being separated from each other in Y-axis direction by a predetermined distance.

    [0039] The actuator plate 42 has an ejection region (jet region) A1 for ink 9, provided at the central portion (the region where the channel rows 421 and 422 are formed) relative to the X-axis direction, as shown in FIG. 4. The actuator plate 42 also has a non-ejection region (non-jet region) A2 for ink 9, provided at the both end portions (the region where the channel rows 421 and 422 are not formed) relative to the X-axis direction. The non-ejection region A2 is on the outer side of the ejection region A1 relative to the X-axis direction. The regions at the both ends of the actuator plate 42 in the Y-axis direction constitute tail portions 420.

    [0040] As illustrated in FIGS. 3 and 4, the channel rows 421 have a plurality of channels C1 extending in the Y-axis direction. The channels C1 are disposed side by side, parallel to each other, by being separated from each other in the X-axis direction by a predetermined distance. The channels C1 are defined by drive walls Wd of the piezoelectric body (actuator plate 42), and form grooves of a depressed shape as viewed in a cross section (see FIG. 3).

    [0041] As with the case of the channel rows 421, the channel rows 422 have a plurality of channels C2 extending in the Y-axis direction. The channels C2 are disposed side by side, parallel to each other, by being separated from each other in the X-axis direction by a predetermined distance. The channels C2 are defined by the drive walls Wd, and form grooves of a depressed shape as viewed in a cross section.

    [0042] As illustrated in FIGS. 3 and 4, the channels C1 include the ejection channels C1e for ejecting ink 9, and dummy channels C1d that do not eject ink 9. In the channel rows 421, the ejection channels C1e and the dummy channels C1d are alternately disposed in the X-axis direction. The ejection channels C1e are in communication with the nozzle holes H1 of the nozzle plate 41, whereas the dummy channels C1d are covered from below by the top surface of the nozzle plate 41, and are not in communication with the nozzle holes H1.

    [0043] As with the case of the channels C1, the channels C2 include the ejection channels C2e for ejecting ink 9, and dummy channels C2d that do not eject ink 9. In the channel rows 422, the ejection channels C2e and the dummy channels C2d are alternately disposed in the X-axis direction. The ejection channels C2e are in communication with the nozzle holes H2 of the nozzle plate 41, whereas the dummy channels C2d are covered from below by the top surface of the nozzle plate 41, and are not in communication with the nozzle holes H2.

    [0044] As illustrated in FIG. 4, the ejection channels C1e and the dummy channels C1d of the channels C1 are alternately disposed with respect to the ejection channels C2e and the dummy channels C2d of the channels C2. That is, in the inkjet head 4 of the present example, the ejection channels C1e of the channels C1, and the ejection channels C2e of the channels C2 are disposed in a staggered fashion. As illustrated in FIG. 3, shallow grooves Dd that are in communication with the outer end portions of the dummy channels C1d and C2d along the Y-axis direction are formed in portions of the actuator plate 42 corresponding to the dummy channels C1d and C2d.

    [0045] As illustrated in FIGS. 3 and 5, drive electrodes Ed extending in the Y-axis direction are provided on the opposing inner surfaces of the drive walls Wd. The drive electrodes Ed include common electrodes Edc provided on inner surfaces facing the ejection channels C1e and C2e, and active electrodes Eda provided on inner surfaces facing the dummy channels C1d and C2d. As illustrated in FIG. 5, the drive electrodes Ed (common electrodes Edc and active electrodes Eda) on the inner surfaces of the drive walls Wd have the same depth as the drive walls Wd (the same depth in Z-axis direction). In the actuator plate 42, an insulating film 42A for preventing electrical shorting between the drive electrodes Ed and the nozzle plate 41 is formed on the surface facing the nozzle plate 41. When the actuator plate 42 is the above-described cantilever-type actuator, the drive electrodes Ed (common electrodes Edc and the active electrodes Eda) are formed about a halfway through the depth (Z-axis direction) of the drive walls Wd on the inner surfaces.

    [0046] A pair of opposing common electrodes Edc in the same ejection channel C1e (or the same ejection channel C2e) are electrically connected to each other via a common terminal (not illustrated). A pair of opposing active electrodes Eda in the same dummy channel C1d (or the same dummy channel C2d) are electrically isolated from each other. On the other hand, a pair of active electrodes Eda facing each other via (on either side of) the same ejection channel C1e (or the same ejection channel C2e) are electrically connected to each other via an active terminal (not illustrated).

    [0047] As illustrated in FIG. 3, flexible printed boards 44 that electrically connect the drive electrodes Ed to a control section (a control section 40 for inkjet heads 4; described later) are mounted on the tail portions 420. The wiring patterns (not illustrated) formed on the flexible printed boards 44 are electrically connected to the common terminals and the active terminals. This enables the control section 40 to apply a drive voltage to each drive electrode Ed via the flexible printed boards 44.

    Cover Plate 43



    [0048] As illustrated in FIG. 3, the cover plate 43 is disposed so as to close the channels C1 and C2 (the channel rows 421 and 422) of the actuator plate 42. Specifically, the cover plate 43 has a plate-shaped structure bonded to the top surface of the actuator plate 42.

    [0049] As shown in FIG. 3, the cover plate 43 has a pair of inlet-side common ink chambers 431a and 432a, and a pair of outlet-side common ink chambers 431b and 432b. Specifically, the inlet-side common ink chamber 431a and the outlet-side common ink chamber 431b are formed in regions corresponding to the channel rows 421 (the plurality of channels C1) of the actuator plate 42. The inlet-side common ink chamber 432a and the outlet-side common ink chamber 432b are formed in regions corresponding to the channel rows 422 (the plurality of channels C2) of the actuator plate 42.

    [0050] The inlet-side common ink chamber 431a has a depressed groove shape, and is formed in the vicinity of the inner end portion of the channels C1 relative to the Y-axis direction. A supply slit Sa is formed in a region of the inlet-side common ink chamber 431a corresponding to each ejection channel C1e, through the thickness (Z-axis direction) of the cover plate 43. Similarly, the inlet-side common ink chamber 432a has a depressed groove shape, and is formed in the vicinity of the inner end portion of the channels C2 relative to the Y-axis direction. The supply slit Sa is also formed in a region of the inlet-side common ink chamber 432a corresponding to each ejection channel C2e. The inlet-side common ink chambers 431a and 432a constitute an inlet portion Tin of the inkjet head 4.

    [0051] As illustrated in FIG. 3, the outlet-side common ink chamber 431b has a depressed groove shape, and is formed in the vicinity of the outer end portion of the channels C1 relative to the Y-axis direction. A discharge slit Sb is formed in a region of each outlet-side common ink chamber431b corresponding to the ejection channel C1e, through the thickness of the cover plate 43. Similarly, the outlet-side common ink chamber 432b has a depressed groove shape, and is formed in the vicinity of the outer end portion of the channels C2 relative to the Y-axis direction. The discharge slit Sb is also formed in a region of the outlet-side common ink chamber 432b corresponding to each ejection channel C2e. The outlet-side common ink chambers 431b and 432b constitute an outlet portion Tout of the inkjet head 4.

    [0052] That is, the inlet-side common ink chamber 431a and the outlet-side common ink chamber 431b are in communication with the ejection channels C1e via the supply slits Sa and the discharge slits Sb, and are not in communication with the dummy channels C1d. In other words, the dummy channels C1d are closed by the bottom portions of the inlet-side common ink chamber 431a and the outlet-side common ink chamber 431b.

    [0053] Similarly, the inlet-side common ink chamber 432a and the outlet-side common ink chamber 432b are in communication with the ejection channels C2e via the supply slits Sa and the discharge slits Sb, and are not in communication with the dummy channels C2d. In other words, the dummy channels C2d are closed by the bottom portions of the inlet-side common ink chamber 432a and the outlet-side common ink chamber 432b.

    Control Section 40



    [0054] As illustrated in FIG. 2, a control section 40 for controlling various operations of the printer 1 is provided in the inkjet head 4 of the present example. The control section 40 controls, for example, the operation of various components, such as the delivery pumps 52a and 52b, in addition to controlling the recording operation of the printer 1 recording an image, texts, and the like (the operation of the inkjet head 4 ejecting ink 9). The control section 40 is configured from, for example, a microcomputer that includes an arithmetic processing unit, and a memory section including various types of memory.

    Basic Operation of Printer 1



    [0055] The printer 1 records (prints) an image, texts, and the like on recording paper P in the manner described below. As an initial state, it is assumed here that the four ink tanks 3 (3Y, 3M, 3C, and 3B) shown in FIG. 1 contain inks of corresponding (four) colors in sufficient amounts. Initially, the inkjet heads 4 have been charged with the inks 9 from the ink tanks 3 through the circulation mechanism 5.

    [0056] In such an initial state, activating the printer 1 rotates the grid rollers 21 of the transport mechanisms 2a and 2b, and transports recording paper P between the grid rollers 21 and the pinch rollers 22 in a transport direction d (X-axis direction). Simultaneously with this transport operation, the drive motor 633 of the drive mechanism 63 rotates the pulleys 631a and 631b to move the endless belt 632. In response, the carriage 62 moves back and forth in the width direction (Y-axis direction) of the recording paper P by being guided by the guide rails 61a and 61b. Here, the inkjet heads 4 (4Y, 4M, 4C, and 4B) appropriately eject inks 9 of four colors onto the recording paper P to record images, texts, and the like on the recording paper P.

    Detailed Operation of Inkjet Head 4



    [0057] The operation of the inkjet head 4 (inkjet operation for ink 9) is described below in detail, with reference to FIGS. 1 to 5. The inkjet head 4 of the present example (a side-shoot, circulatory inkjet head) ejects ink 9 in shear mode, as follows.

    [0058] In response to the carriage 62 (see FIG. 1) having started its reciprocal movement, the control section 40 applies a drive voltage to the drive electrodes Ed (common electrodes Edc and active electrodes Eda) of the inkjet head 4 via the flexible printed boards 44. Specifically, the control section 40 applies a drive voltage to the drive electrodes Ed disposed on the pair of drive walls Wd defining the ejection channels C1e and C2e. This causes the pair of drive walls Wd to deform outwardly toward the dummy channels C1d and C2d adjacent the ejection channels C1e and C2e (see FIG. 5).

    [0059] That is, the ejection channels C1e and C2e increase their volume as a result of the flexural deformation of the pair of drive walls Wd. The ink 9 stored in the inlet-side common ink chambers 431a and 432a is guided into the ejection channels C1e and C2e as the volume of ejection channels C1e and C2e increases (see FIG. 3).

    [0060] The ink 9 guided into the ejection channels C1e and C2e creates a pressure wave, and propagates into the ejection channels C1e and C2e. The drive voltage applied to the drive electrodes Ed becomes 0 (zero) volt at the timing when the pressure wave reaches the nozzle holes H1 and H2 of the nozzle plate 41. In response, the drive walls Wd return to their original shape from the flexurally deformed state, bringing the ejection channels C1e and C2e back to their original volume (see FIG. 5).

    [0061] The pressure inside the ejection channels C1e and C2e increases, and pressurizes the ink 9 inside the ejection channels C1e and C2e as the volume of the ejection channels C1e and C2e is restored. This causes the ink 9 to be ejected to outside (toward the recording paper P) in the form of droplets through the nozzle holes H1 and H2 (see FIG. 5). The inkjet head 4 ejects (discharges) the ink 9 in this manner, and records images, texts, and the like on the recording paper P. The ink 9 can be ejected in a straight line (good straight-line stability) at high speed because of the tapered shape of the nozzle holes H1 and H2 of the present example of gradually decreasing diameter toward the bottom (see FIG. 5). This enables high-quality recording.

    Method for Manufacturing Nozzle Plate 41



    [0062] A method for manufacturing the nozzle plate 41 is described below. FIG. 9 is a diagram representing an exemplary procedure of manufacturing the nozzle plate 41. FIGS. 10A to 10D are cross sectional views representing an example of manufacturing steps of the nozzle plate 41.

    [0063] First, a metal substrate 100 is prepared (FIG. 10A). The metal substrate 100 is formed of a stainless steel such as SUS316L and SUS304. The metal substrate 100 has a first principal surface 100A on one side, and a second principal surface 100B on the other side. The metal substrate 100 becomes the metal substrate 410 after working. The first principal surface 100A of the metal substrate 100 is the surface that becomes the inlet-side principal surface 410A of the metal substrate 410, and the second principal surface 100B of the metal substrate 100 is the surface that becomes the outlet-side principal surface 410B of the metal substrate 410.

    [0064] The next step is punching (step S101). First, the metal substrate 100 is fixed on a die 300 with the first principal surface 100A facing up. The die 300 has a plurality of through holes 300H having the same pitch as the nozzle holes H1 and H2 of the nozzle plate 41 in the X-axis direction. The through hole 300H has a larger diameter than a cylindrical portion 220 of a punch 200 (described later). The first principal surface 100A of the metal substrate 100 is then pressed with one or more punches 200. Specifically, the first principal surface 100A of the metal substrate 100 is pressed with one or more punches 200 in portions facing the through holes 300H. This forms a plurality of indentations 100C in the first principal surface 100A, and, at the same time, raised portions 100D in portions of the second principal surface 100B facing the indentations 100C (FIG. 10B). Here, the plurality of indentations 100C, and the plurality of raised portions 100D are formed in a line in the metal substrate 100.

    [0065] The punch 200 has a frustoconical tapered portion 210, and the cylindrical portion 220 formed in contact with an end of the tapered portion 210. The indentation 100C formed under the pressure of the punch 200 therefore has an inverted shape from the shape of the punch 200. Specifically, the indentation 100C has a frustoconical tapered hole portion, and a cylindrical hole portion continuous from the tapered hole portion. The indentation 100C is deeper than the thickness of the metal substrate 100 (the distance between the first principal surface 100A and the second principal surface 100B).

    [0066] The next step is polishing (step S102). Specifically, the raised portions 100D are removed by mechanical polishing to open the indentations 100C, and form the nozzle holes H1 and H2 (FIG. 10C). Here, the surface is mechanically polished in such a manner that the polished surface in the outlet edge regions Ea of the nozzle holes H1 and H2 has the surface roughness Ra1 (arithmetic mean roughness Ra) that is smaller than a surface roughness Ra2 (arithmetic mean roughness Ra) of the surrounding regions Eb around the outlet edge regions Ea (polished surface). The mechanical polishing may be performed with, for example, a tape 500 (tape polishing). The tape 500 is, for example, a long polyester film of about 75-µm thick with a plurality of abrasive grains fixed over substantially the whole surface on one side of the film.

    [0067] There are cases where the pressure of the punch 200 causes a wave near the inlet Hb of the nozzle holes H1 and H2 (end portions of the nozzle holes H1 and H2 on the actuator plate 42 side). In this case, the first principal surface 100A may be flattened by mechanical polishing when removing the raised portions 100D. This produces the substantially flat first principal surface 100A.

    [0068] This is followed by formation of the liquid repellent film 413 (step S103). Specifically, the liquid repellent film 413 is formed that directly contacts the second principal surface 100B (FIG. 10D). For example, a mask having openings in positions corresponding to the surrounding regions Eb (not illustrated) is disposed on the second principal surface 100B, and a material containing a material of the liquid repellent film 413 (for example, a fluorine-based silane coupling agent) is fixed over the whole surface, including the mask, by, for example, dipping, spraying, brush coating, fabric coating, spin coating, roller coating, coating with a knife coater, or coating with a film coater. The film formed by using these methods is then dried to form the liquid repellent film 413. This completes the nozzle plate 41.

    Advantages



    [0069] The following describes advantages of the nozzle plate 41 as a jet hole plate according to an example of the present disclosure.

    [0070] Printers equipped with inkjet heads are used in a wide range of applications. An inkjet head includes a plurality of laminated plates including a nozzle plate having formed therein large numbers of nozzle holes, and is configured to eject liquid, specifically, ink, against a target recording medium through the nozzle holes. A long life is desired in such a nozzle plate. However, traditional nozzle plates are often cleaned as a part of regular maintenance by wiping the surface where the outlets of the nozzle holes are formed. Here, the friction of wiping may cause detachment of the liquid repellent film provided on the ejection surface, and, in this case, the nozzle plate may become dysfunctional, with the result that the life of the nozzle plate is cut short.

    [0071] In the nozzle plate 41 according to the present example, the outlet edge regions Ea of the nozzle holes H1 and H2 on the outlet-side principal surface 410B of the metal substrate 410 constituting the nozzle plate 41 has a surface roughness Ra1 (arithmetic mean roughness Ra) that is smaller than the surface roughness Ra2 (arithmetic mean roughness Ra) of the surrounding regions Eb around the outlet edge regions Ea. Because the outlet edge region Ea is smoother than the surrounding region Eb, the surface roughness at the edges of the outlets becomes less of a factor of undesirable effects on ejection of the ink, such as attenuation and deflection. This ensures ejection quality. Additionally, because of the rough surrounding region Eb, the liquid repellent film 413 has good adhesion for the outlet-side principal surface 410B. Accordingly, the liquid repellent film 413 provided on the outlet-side principal surface 410B does not easily detach itself under the friction of wiping. This makes it possible to provide a longer life for the nozzle plate 41 while maintaining the ejection quality.

    [0072] In the nozzle plate 41 according to the present example, the outlet edge region Ea is a polished surface formed by mechanical polishing. Because the outlet edge region Ea is a polished surface smoother than the surrounding region Eb, the ejection quality is maintained. Mechanical polishing also enables easier selective polishing of only the outlet edge region Ea compared to chemical polishing, and provides roughness to the surrounding region Eb. The liquid repellent film 413 therefore has good adhesion for the outlet-side principal surface 410B. Accordingly, the liquid repellent film 413 provided on the outlet-side principal surface 410B does not easily detach itself under the friction of wiping. This makes it possible to provide a longer life for the nozzle plate 41 while maintaining the ejection quality.

    [0073] The nozzle plate 41 according to the present example ncludes the liquid repellent film 413 that directly contacts the outlet-side principal surface 410B. That is, in the present example, the liquid repellent film 413 is in direct contact with the outlet-side principal surface 410B that includes the rough surrounding region Eb, and the liquid repellent film 413 has good adhesion for the outlet-side principal surface 410B. Accordingly, the liquid repellent film 413 provided on the outlet-side principal surface 410B does not easily detach itself under the friction of wiping. With the second principal surface 100B (outlet-side principal surface 410B) protected by the liquid repellent film 413, the nozzle plate 41 can have a longer life.

    [0074] In the method for manufacturing of the nozzle plate 41 according to the present example, the mechanical polishing that forms the nozzle holes H1 and H2 is performed in such a manner that the polished surface formed in the outlet edge regions Ea of the nozzle holes H1 and H2 by mechanical polishing has the surface roughness Ra1 (arithmetic mean roughness Ra) that is smaller than the surface roughness Ra2 (arithmetic mean roughness Ra) of the surrounding regions Eb around the outlet edge regions Ea (polished surface). Because the outlet edge region Ea is smoother than the surrounding region Eb, the ejection quality is maintained. Additionally, the surrounding region Eb has roughness, and the liquid repellent film 413 has good adhesion for the outlet-side principal surface 410B. Accordingly, the liquid repellent film 413 provided on the outlet-side principal surface 410B does not easily detach itself under the friction of wiping. This makes it possible to provide a longer life for the nozzle plate 41 while maintaining the ejection quality.

    [0075] The method for manufacturing the nozzle plate 41 according to the present example forms the liquid repellent film 413 that directly contacts the second principal surface 100B. That is, in the present embodiment, the liquid repellent film 413 is in direct contact with the second principal surface 100B (outlet-side principal surface 410B) that includes the rough surrounding region Eb, and the liquid repellent film 413 has good adhesion to the second principal surface 100B (outlet-side principal surface 410B). Accordingly, the liquid repellent film 413 provided on the second principal surface 100B (outlet-side principal surface 410B) does not easily detach itself under the friction of wiping. With the second principal surface 100B (outlet-side principal surface 410B) protected by the liquid repellent film 413, the nozzle plate 41 can have a longer life.

    2. Variations


    Variation A (preferred embodiment)



    [0076] In the foregoing example, the outlet edge regions Ea are provided by being separated from each other on the outlet-side principal surface 410B. However, in the embodiment of the invention as illustrated in FIGS. 11 and 12, the outlet edge regions Ea formed in a line are in contact with each other between the adjacent outlet edge regions Ea. FIG. 11 is a partially magnified view representing an exemplary structure (X-Y plane exemplary structure) of the bottom surface of the nozzle plate 41 according to variation A. FIG. 12 is a partially magnified view representing an exemplary structure (X-Y plane exemplary structure) of the bottom surface of the nozzle plate 41, without the liquid repellent film 413 of FIG. 11. In variation A, when the outlet edge region Ea has a circular ring shape, the outer diameter of the outlet edge region Ea is larger than the pitch of the nozzle holes H1 and H2.

    [0077] A method for manufacturing the nozzle plate 41 according to this variation is described below. FIG. 13 is a cross sectional view representing an example of a manufacturing step of the nozzle plate 41 according to the present variation. The method for manufacturing the nozzle plate 41 according to the present variation shares the same steps as the method for manufacturing the nozzle plate 41 according to the example, except for steps after step S101 (FIGS. 10A and 10B). Accordingly, the following descriptions of the manufacturing steps begin with a step corresponding to step S102 of the method for manufacturing the nozzle plate 41 according to the example.

    [0078] The punching is followed by polishing (step S102). Specifically, the raised portions 100D are removed by mechanical polishing to open the indentations 100C, and form the nozzle holes H1 and H2 (FIG. 13). Here, the surface is mechanically polished in such a manner that the polished surface in the outlet edge regions Ea of the nozzle holes H1 and H2 has the surface roughness Ra1 (arithmetic mean roughness Ra) that is smaller than the surface roughness Ra2 (arithmetic mean roughness Ra) of the surrounding regions Eb around the outlet edge regions Ea (polished surface). The mechanical polishing may be performed with, for example, the tape 500 (tape polishing). In addition to forming the nozzle holes H1 and H2 in a line, the raised portions 100D are polished so that the outlet edge regions Ea (polished surface) become in contact with each other between the adjacent outlet edge regions Ea (polished surface). This is followed by formation of the liquid repellent film 413 (step S103). Specifically, the liquid repellent film 413 is formed that directly contacts the second principal surface 100B (surrounding region Eb) (FIG. 10D). This completes the nozzle plate 41 according to the present variation.

    [0079] In the nozzle plate 41 according to the present variation, the outlet edge regions Ea formed in a line are in contact with each other between the adjacent outlet edge regions Ea. When the distance between the nozzle holes H1 (or the distance between the nozzle holes H2) is short, it may not be always easy to polish the surface without joining the polished surfaces because of procedural accuracy limitations. Such accuracy limitations can be overcome by allowing the polished surfaces to join together, provided that it does not cause any problem. This improves the ease of polishing. That is, the ejection quality can be maintained at a low manufacturing cost.

    [0080] The method for manufacturing the nozzle plate 41 according to the present variation forms the nozzle holes H1 and H2 in a line, and polishes the raised portions 100D in such a manner that the outlet edge regions Ea (polished surfaces) become in contact with each other between the adjacent outlet edge regions Ea (polished surfaces). When the distance between the nozzle holes H1 (or the distance between the nozzle holes H2) is short, it may not be always easy to polish the surface without joining the polished surfaces because of procedural accuracy limitations. Such accuracy limitations can be overcome by allowing the polished surfaces to join together, provided that it does not cause any problem. This improves the ease of polishing. That is, the ejection quality can be maintained at a low manufacturing cost.

    Variation B



    [0081] For example, in the foregoing example and the variation depicting the preferred embodiment, the liquid repellent film 413 is in direct contact with the outlet-side principal surface 410B. However, for example, as illustrated in FIG. 14, the liquid repellent film 413 may contact the outlet-side principal surface 410B via an adhesive layer 414. The adhesive layer 414 is a layer for improving the adhesion between the outlet-side principal surface 410B (surrounding region Eb) and the liquid repellent film 413. Examples of the material of the adhesive layer 414 include diamond-like carbon (DLC), and a silane coupling agent. For manufacture of the nozzle plate 41 according to the present variation, the liquid repellent film 413 that contacts the outlet-side principal surface 410B via the adhesive layer 414 is formed after forming the adhesive layer 414 on the outlet-side principal surface 410B (surrounding region Eb).

    [0082] The nozzle plate 41 according to the present variation includes the liquid repellent film 413 that contacts the outlet-side principal surface 410B via the adhesive layer 414. That is, in the present variation, the liquid repellent film 413 is in contact with the outlet-side principal surface 410B that includes the rough surrounding region Eb, via the adhesive layer 414. The liquid repellent film 413 therefore has good adhesion for the outlet-side principal surface 410B. Accordingly, the liquid repellent film 413 provided on the outlet-side principal surface 410B does not easily detach itself under the friction of wiping. With the second principal surface 100B (outlet-side principal surface 410B) protected by the liquid repellent film 413, the nozzle plate 41 can have a longer life.

    [0083] The method for manufacturing the nozzle plate 41 according to the present variation forms the liquid repellent film 413 that contacts the second principal surface 100B via the adhesive layer 414. That is, in the present variation, the liquid repellent film 413 is in contact with the second principal surface 100B (outlet-side principal surface 410B) that includes the rough surrounding region Eb, via the adhesive layer 414. The liquid repellent film 413 therefore has good adhesion to the second principal surface 100B (outlet-side principal surface 410B). Accordingly, the liquid repellent film 413 provided on the second principal surface 100B (outlet-side principal surface 410B) does not easily detach itself under the friction of wiping. With the second principal surface 100B (outlet-side principal surface 410B) protected by the liquid repellent film 413, the nozzle plate 41 can have a longer life.

    Other Variations



    [0084] While the foregoing examples and variations described exemplary structures (e.g., shapes, positions, and numbers) of different members of the printer 1 and the inkjet head 4, the structures of these and other members are not limited to the ones described in the foregoing examples and variations, and these may have other structures, including shapes, positions, and numbers. The values and ranges of various parameters, and the relationships between these parameters described in the foregoing example and variations are also not limited to the ones described in the foregoing example and variations, and the parameters may have different values, ranges and relationships.

    [0085] Specifically, for example, the foregoing example and variations described the two-row inkjet head 4 (with two rows of nozzles 411 and 412). However, the present disclosure is not limited to this example. Specifically, for example, the inkjet head may be a single-row inkjet head (with a single row of nozzles), or an inkjet head having three or more rows (with three or more rows of nozzles).

    [0086] For example, the foregoing example and variations described the nozzle rows 411 and 412 extending in a straight line along the X-axis direction. However, the present disclosure is not limited to this example. For example, the nozzle rows 411 and 412 may extend in an oblique direction. The shape of the nozzle holes H1 and H2 is also not limited to the circular shape described in the foregoing example and variations, and may be, for example, a polygonal shape such as a triangle, or an elliptical or a star shape.

    [0087] For example, the foregoing example and variations described the inkjet head 4 of a side shoot-type. However, the present disclosure is not limited to this example. For example, the inkjet head 4 may be of a different type. For example, the foregoing example and variations described the inkjet head 4 as a circulatory inkjet head. However, the present disclosure is not limited to this example. For example, the inkjet head 4 may be a non-circulatory inkjet head.

    [0088] For example, in the foregoing example and variations, the die 300 may have the single through hole 300H when the single punch 200 is used for punching. Here, the single punch 200 and the single through hole 300H work as a pair, and can form a plurality of raised portions 100D in a line by moving relative to the metal substrate 410.

    [0089] The series of processes described in the foregoing example and variations may be performed on hardware (circuit) or software (program). In the case of software, the software is configured as a set of programs that causes a computer to execute various functions. The program may be, for example, a preinstalled program in the computer, and may be installed afterwards in the computer from a network or a recording medium.

    [0090] The foregoing example and variations described the printer 1 (inkjet printer) as a specific example of a liquid jet recording apparatus of the present disclosure. However, the present disclosure is not limited to this example, and may be applied to devices and apparatuses other than inkjet printers. In other words, a liquid jet head (inkjet head 4) and a jet hole plate (nozzle plate 41) of the present disclosure may be applied to devices and apparatuses other than inkjet printers. Specifically, for example, a liquid jet head and a jet hole plate of the present disclosure may be applied to devices such as facsimile machines, and on-demand printers.

    [0091] The foregoing example and variations described recording paper P as a target of recording by the printer 1. However, the recording target of a liquid jet recording apparatus of the present disclosure is not limited to this example. For example, texts and patterns can be formed by jetting ink onto various materials such as a boxboard, a fabric, a plastic, and a metal. The recording target is not necessarily required to have a flat surface shape, and a liquid jet recording apparatus of the present disclosure can be used for painting and decoration of various solid objects, including, for example, food products, building materials such as tiles, furniture, and automobiles. A liquid jet recording apparatus of the present disclosure also can print on fibers, or create a solid object by jetting and solidifying ink (i.e., a 3D printer).

    [0092] The examples described above may be applied in any combinations.

    [0093] The effects described in the specification are merely illustrative and are not restrictive, and may include other effects.


    Claims

    1. A jet hole plate (41) for use in a liquid jet head (4),
    the jet hole plate comprising a metal substrate (410) provided with a plurality of jet holes (H),
    the metal substrate having a principal surface (410B) provided with outlets (Ha) of the jet holes,
    wherein, on the principal surface, a surface roughness in outlet edge regions (Ea) of the jet holes is smaller than that in surrounding regions (Eb) around the outlet edge regions,
    wherein the jet holes are formed in a line on the principal surface; characterized in that
    the outlet edge regions are in contact with each other between adjacent outlet edge regions.
     
    2. The jet hole plate according to claim 1, wherein the outlet edge regions (Ea) have a circular ring shape and the outer diameter of the outlet edge regions (Ea) is larger than the pitch of the jet holes.
     
    3. The jet hole plate according to claims 1 or 2, wherein the outlet edge regions represent a polished surface formed by mechanical polishing.
     
    4. The jet hole plate according to any one of claims 1 to 3, further comprising a liquid repellent film (413) that is in contact with the principal surface either directly or via an adhesive layer (414).
     
    5. A jet hole plate according to any one of the preceding claims, wherein the surface roughness is arithmetic mean roughness (Ra).
     
    6. A liquid jet head (4) comprising the jet hole plate (41) according to any one of claims 1 to 5.
     
    7. A liquid jet recording apparatus (1) comprising:

    the liquid jet head (4) according to claim 6; and

    a container (3) for storing liquid to be supplied to the liquid jet head.


     
    8. A method for manufacturing a jet hole plate (41),
    the method comprising:

    a punching step (S101) of pressing a first principal surface of a metal substrate (100) with one or more punches (200) to form a plurality of indentations (100C) in the first principal surface, and to form raised portions (100D) in a second principal surface (410B) of the metal substrate in positions opposite the indentations; and

    a polishing step (S102) of removing the raised portions by mechanical polishing to penetrate the metal substrate at the indentations to thereby form a plurality of jet holes (H1, H2), so that a surface roughness in polished surfaces formed in outlet edge regions (Ea) of the jet holes is smaller than that in surrounding regions (Eb) around the polished surfaces, and

    wherein in the punching step, the plurality of indentations is formed in a line; the method characterized in that, and

    in the polishing step, the raised portions are polished so as to form the plurality of jet holes in a line, and to bring the polished surfaces into contact with each other between adjacent polished surfaces.


     
    9. The method according to claim 8, wherein the outlet edge regions (Ea) have a circular ring shape and the outer diameter of the outlet edge regions (Ea) is larger than the pitch of the jet holes.
     
    10. The method according to claim 8 or 9, which further comprises a film forming step (S103) of forming a liquid repellent film (413) that contacts the second principal surface either directly or via an adhesive layer (414).
     


    Ansprüche

    1. Strahllochplatte (41) zur Verwendung in einem Flüssigkeitsstrahlkopf (4),
    wobei die Strahllochplatte ein Metallsubstrat (410) umfasst, das mit mehreren Strahllöchern (H) versehen ist,
    wobei das Metallsubstrat eine Hauptoberfläche (410B) aufweist, die mit Auslässen (Ha) der Strahllöcher versehen ist,
    wobei auf der Hauptoberfläche eine Oberflächenrauheit in Auslasskantenbereichen (Ea) der Strahllöcher kleiner ist als die in umliegenden Bereichen (Eb) um die Auslasskantenbereiche,
    wobei die Strahllöcher in einer Linie auf der Hauptoberfläche ausgebildet sind; dadurch gekennzeichnet, dass
    die Auslasskantenbereiche zwischen benachbarten Auslasskantenbereichen in Kontakt miteinander stehen.
     
    2. Strahllochplatte nach Anspruch 1, wobei die Auslasskantenbereiche (Ea) eine kreisförmige Ringform aufweisen und der Außendurchmesser der Auslasskantenbereiche (Ea) größer als die Steigung der Strahllöcher ist.
     
    3. Strahllochplatte nach Anspruch 1 oder 2, wobei die Auslasskantenbereiche eine polierte Oberfläche darstellen, die durch mechanisches Polieren gebildet wird.
     
    4. Strahllochplatte nach einem der Ansprüche 1 bis 3, ferner umfassend einen flüssigkeitsabweisenden Film (413), der entweder direkt oder über eine Klebeschicht (414) mit der Hauptoberfläche in Kontakt steht.
     
    5. Strahllochplatte nach einem der vorhergehenden Ansprüche, wobei die Oberflächenrauheit die arithmetische mittlere Rauheit (Ra) ist.
     
    6. Flüssigkeitsstrahlkopf (4), umfassend die Strahllochplatte (41) nach einem der Ansprüche 1 bis 5.
     
    7. Flüssigkeitsstrahl-Aufzeichnungsvorrichtung (1), umfassend:

    den Flüssigkeitsstrahlkopf (4) nach Anspruch 6; und

    einen Behälter (3) zum Speichern von Flüssigkeit, die dem Flüssigkeitsstrahlkopf zugeführt werden soll.


     
    8. Verfahren zur Herstellung einer Strahllochplatte (41), wobei das Verfahren umfasst:

    einen Stanzschritt (S101) zum Pressen einer ersten Hauptoberfläche eines Metallsubstrats (100) mit einem oder mehreren Stempeln (200), um mehrere Vertiefungen (100C) in der ersten Hauptoberfläche zu bilden und um erhöhte Abschnitte (100D) in einer zweiten Hauptoberfläche (410B) des Metallsubstrats in Positionen gegenüber den Vertiefungen zu bilden; und

    ein Polierschritt (S102) zum Entfernen der erhöhten Abschnitte durch mechanisches Polieren, um das Metallsubstrat an den Vertiefungen zu durchdringen, wodurch dadurch mehrere Strahllöcher (H1, H2) gebildet werden, so dass sich eine Oberflächenrauheit in polierten Oberflächen, die in Auslasskantenbereichen (Ea) der Strahllöcher gebildet sind, kleiner ist als in den umliegenden Bereichen (Eb) um die polierten Oberflächen, und

    wobei im Stanzschritt die mehreren Vertiefungen in einer Linie gebildet werden; wobei das Verfahren dadurch gekennzeichnet ist, dass

    im Polierschritt die erhabenen Abschnitte poliert werden, um die mehreren Strahllöcher in einer Linie zu bilden, und die polierten Oberflächen zwischen benachbarten polierten Oberflächen miteinander in Kontakt zu bringen.


     
    9. Verfahren nach Anspruch 8, wobei die Auslasskantenbereiche (Ea) eine kreisförmige Ringform aufweisen und der Außendurchmesser der Auslasskantenbereiche (Ea) größer als die Steigung der Strahllöcher ist.
     
    10. Verfahren nach Anspruch 8 oder 9, das ferner einen Filmbildungsschritt (S103) zum Bilden eines flüssigkeitsabweisenden Films (413) umfasst, der die zweite Hauptoberfläche entweder direkt oder über eine Klebeschicht (414) berührt.
     


    Revendications

    1. Plaque à trous de projection (41) destinée à être utilisée dans une tête de projection de liquide (4),
    la plaque à trous de projection (410) étant pourvue d'une pluralité de trous de projection (H),
    le substrat métallique comportant une surface principale (410B) pourvue des sorties (Ha) des trous de projection, dans laquelle,
    sur la surface principale, une rugosité de surface dans des zones périphériques de sortie (Ea) des trous de projection est plus réduite que dans les zones environnantes (Eb) autour des zones périphériques de sortie,
    les trous de projection sont formés caractériser en une ligne sur la surface principale, caractérisée en ce que les zones périphériques de sortie sont en contact les unes avec les autres entre des zones périphériques de sortie adjacentes.
     
    2. Plaque à trous de projection selon la revendication 1, dans laquelle zone périphérique de sortie (Ea) ont une forme annulaire et le diamètre extérieur d'une zone périphérique de sortie (Ea) est supérieur au pas des trous de projection.
     
    3. Plaque à trous de projection selon la revendication 1 ou 2, dans laquelle les zones périphériques de sortie constituent une surface polie formée par polissage mécanique.
     
    4. Plaque à trous de projection selon l'une quelconque des revendications 1 à 3, comprenant en outre un film repoussant le liquide (413) qui est en contact avec la surface principale, soit directement, soit par l'intermédiaire d'une couche adhésive (414).
     
    5. Plaque à trous de projection selon l'une quelconque des revendications précédentes, dans laquelle la rugosité de surface est une rugosité moyenne arithmétique (Ra).
     
    6. Tête de projection de liquide (4) comprenant la plaque à trous de projection (41) selon l'une quelconque des revendications 1 à 5.
     
    7. Appareil d'enregistrement de projection de liquide (1) comprenant :

    la tête de projection de liquide (4) selon la revendication 6 ; et

    un réservoir (3) pour stocker du liquide à fournir à la tête de projection de liquide.


     
    8. Procédé de fabrication d'une plaque à trous de projection (41),
    ce procédé comprenant :

    une étape de poinçonnage (S101) avec compression d'une première surface principale d'un substrat métallique (100) avec un ou plusieurs poinçons (200) pour former une pluralité d'indentations (100C) dans la première surface principale, et pour former des sections surélevées (100D) dans une seconde surface principale (410B) du substrat métallique à des positions opposées aux indentations, et

    une étape de polissage (S102) avec élimination des sections surélevées par polissage mécanique pour pénétrer dans le substrat métallique au niveau des indentations pour former ainsi une pluralité de trous de projection (H1, H2), de manière à ce qu'une rugosité de surface dans des surfaces polies formées dans des zones périphériques de sortie (Ea) des trous de projection soit plus réduite que dans des zones environnantes (Eb) autour des surfaces polies, et

    dans laquelle, dans l'étape de poinçonnage, la pluralité d'indentations sont formées sur une ligne ;

    ce procédé étant caractérisé en ce que,

    dans l'étape de polissage, les sections surélevées sont polies de manière à former la pluralité de trous de projection sur une ligne, et à amener les surfaces polies en contact les unes avec les autres entre des surfaces polies adjacentes.


     
    9. Procédé selon la revendication 8, dans lequel les zones périphériques de sortie (Ea) ont une forme annulaire circulaire et le diamètre extérieur des zones périphériques de sortie (Ea) est supérieur au pas des trous de projection.
     
    10. Procédé selon la revendication 8 ou 9, qui comprend en outre une étape de formage de film (S103) pour le formage d'un film repoussant le liquide (413) qui est en contact avec la seconde surface principale soit directement, soit par l'intermédiaire d'une couche adhésive (414).
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description