Patent Publication Number: US-2023141751-A1

Title: Head, head module, and apparatus that discharges liquid

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2021-183763, filed on Nov. 10, 2021, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     The present embodiments relate to a head, a head module, and an apparatus that discharges liquid. 
     Related Art 
     A head, such as a liquid discharge head, includes an electrode of a drive element that pressurizes a pressure chamber bonded to a wiring with a conductive film, such as an anisotropic conductive film (ACF), to be electrically connected. 
     The head includes a SiO 2  diaphragm plate with a piezoelectric element integrally formed on a silicon substrate that serves as a channel plate, an electrode wiring leading to an electrode of the piezoelectric element on the diaphragm plate, and a flexible wiring connected to the electrode wiring with an ACF. 
     SUMMARY 
     A head includes: a silicon substrate; an insulating film on the silicon substrate; an electrode wiring on the insulating film; a flexible wiring connected to the electrode wiring; and a conductive film electrically connects the flexible wiring and the electrode wiring in a bonding area. The silicon substrate has an exposed area on a surface of the silicon substrate facing the insulating film, and the exposed area is in a vicinity of the bonding area and is exposed from the insulating film. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein: 
         FIG.  1    is an explanatory diagram for a perspective view of a head according to the first embodiment of the present disclosure; 
         FIG.  2    is an explanatory diagram for a side face of the head; 
         FIG.  3    is an explanatory diagram in which the relevant part of the head is enlarged; 
         FIG.  4    is an explanatory diagram in which the relevant part is enlarged, which is to be provided for explanation of the functions of the embodiment; 
         FIG.  5    is an explanatory diagram in which the relevant part of Comparative Example 1 is enlarged; 
         FIG.  6    is an explanatory diagram in which the relevant part of the head according to the second embodiment of the present disclosure is enlarged; 
         FIG.  7    is an explanatory diagram for a cross section of the head module according to the third embodiment of the present disclosure along the lateral direction of the head; 
         FIG.  8    is an explanatory diagram for an exploded perspective view of the head module; 
         FIG.  9    is an explanatory diagram for an exploded perspective view of the head module; 
         FIG.  10    is an explanatory diagram for an exploded perspective view from the nozzle surface side of the head module; 
         FIG.  11    is a schematic explanatory diagram of an example of the apparatus that discharges liquid according to the present embodiments; and 
         FIG.  12    is a planar explanatory diagram of an example of a discharge unit of the apparatus. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result. 
     Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Hereinafter, embodiments of the present disclosure are explained with reference to the accompanying drawings. The first embodiment of the present disclosure is explained with reference to  FIG.  1    through  FIG.  3   . 
       FIG.  1    is an explanatory diagram for a perspective view of a head according to the present embodiment. 
       FIG.  2    is an explanatory diagram for a side face of the head. 
       FIG.  3    is an explanatory diagram in which the relevant part of the head is enlarged. 
     The head  1  includes a nozzle plate  10  in which a nozzle that discharges liquid is formed, an individual channel plate  20  in which a pressure chamber or the like communicating with the nozzle is formed, a diaphragm plate  30  with which a deformable wall surface of the pressure chamber is formed, a piezoelectric element  40  provided in the diaphragm plate  30 , and a common channel member  70  that supplies liquid for the pressure chamber or the like. 
     Here, the individual channel plate  20  is formed with a silicon substrate. The diaphragm plate  30  is formed of silicon oxide (SiO2) and is an insulating film formed on the individual channel plate  20  which is a silicon substrate. Thus, the individual channel plate  20  is also referred to as the “silicon substrate”. The diaphragm plate  30  is also referred to as the “insulating film”. 
     On the diaphragm plate  30  which is an insulating film, the electrode wiring  146  that is connected to the lower electrode of the piezoelectric element  40  is formed. Further, the electrode wiring  146  is bonded to the wiring  90   a  of the flexible wiring  90  with an anisotropic conductive film  121 , which is a conductive film, to be electrically connected. The anisotropic conductive film  121  is also referred to as “ACF” or the “conductive film”. 
     On the surface where the insulating film (diaphragm plate  30 ) is provided on the individual channel plate  20  which is a silicon substrate, a silicon exposed area  20   a  where the insulating film (diaphragm plate  30 ) is not provided exists around the area where the flexible wiring  90  and the electrode wiring  146  are bonded via the ACF  121 . The silicon exposed area  20   a  is also simply referred to as an “exposed area”. The silicon exposed area  20   a  is provided at an end of the individual channel plate  20 , which is a silicon substrate. 
     The ACF  121  (conductive film) electrically connects the flexible wiring  90  and the electrode wiring  146  in a bonding area, and individual channel plate  20  (silicon substrate) has the silicon exposed area  20   a  on a surface of the individual channel plate  20  (silicon substrate) facing the insulating film (diaphragm plate  30 ). The silicon exposed area  20   a  is in a vicinity of the bonding area and is exposed from the insulating film (diaphragm plate  30 ). 
     In the present embodiment, the silicon exposed area  20   a  is formed with the dicing line  122  for dividing the Si wafer, in which components such as multiple individual channel plates  20  and the diaphragm plates  30  are formed, into individual components. No diaphragm plate  30  is formed in the dicing line  122 . 
     Further, the cover member  103  that serves as a nozzle cover is bonded to the bonding surface  20   b  on the nozzle plate  10  side of the individual channel plate  20 . 
     Next, the functions of the present embodiment are explained with reference to  FIG.  4    and  FIG.  5   . 
       FIG.  4    is an explanatory diagram for a cross section in which the relevant part is enlarged, which is to be provided for explanation of the functions of the embodiment. 
       FIG.  5    is an explanatory diagram for a cross section in which the relevant part of Comparative Example 1 is enlarged. 
     At the time of bonding the flexible wiring  90  to the electrode wiring  146  with the ACF  121 , the ACF  121  is widened by the pressure bonding. Here, if the widened ACF  121  protrudes beyond the end surface of the individual channel plate  20  up to the height of the bonding surface of the nozzle plate  10  as illustrated in  FIG.  4   , the protrusion part  121   a  of the ACF  121  interferes the cover member  103  at the time of bonding the cover member  103  to the bonding surface  20   b  of the individual channel plate  20 , which results in a poor bonding of the cover member  103 . 
     Therefore, whether the protrusion part  121   a  of the ACF  121  protrudes beyond the bonding surface  20   b  of the cover member  103  of the individual channel plate  20  has to be checked. 
     In this case, if the entire surface of the bonding surface  20   b  is checked with a microscope or the like to detect any protrusion in the bonding process of the cover member  103 , there will be many steps. 
     Thus, in the present embodiment, on the individual channel plate  20  which is a silicon substrate, the silicon exposed area  20   a  where the insulating film (diaphragm plate  30 ) is not provided is formed around the area where the flexible wiring  90  and the electrode wiring  146  are bonded with the ACF  121 . 
     Accordingly, since a current leakage occurs if the ACF  121  seeps onto the silicon exposed area  20   a,  it is possible to detect the seeping of the ACF  121  by detecting the presence or absence of the current leakage without checking the external appearance. 
     Here, since the silicon exposed area  20   a  is provided at an end of the individual channel plate  20  which is a silicon substrate, it is possible to detect and eliminate the current leakage at the stage before the ACF  121  starts to seep onto the end surface of the individual channel plate  20 , and thus a poor bonding of the cover member  103  is prevented. 
     In contrast, in Comparative Example 1 illustrated in  FIG.  5   , the insulating film  130  with which the diaphragm plate  30  is formed is formed up to the end surface  20   c  of the individual channel plate  20  which is a silicon substrate. 
     Therefore, even if the ACF 121  protrudes, the individual channel plate  20  and the ACF  121  do not conduct, and thus the protrusion of the ACF  121  may not be detected with a current leakage or the like. Therefore, the amount of protrusion of the ACF  121  has to be quantitatively checked. 
     Next, the second embodiment of the present disclosure is explained with reference to  FIG.  6   . 
     As with  FIG.  3   ,  FIG.  6    is an explanatory diagram for a cross section in which the relevant part of the head according to the embodiment is enlarged. 
     In the present embodiment, the rising part  30   a,  which is formed by raising a part of the insulating film that forms the diaphragm plate  30  toward the electrode wiring  146  at the end surface of the electrode wiring  146 , is provided. Further, the folding part  30   b  that covers a part of the surface of the electrode wiring  146  is also provided integrally with the rising part  30   a.    
     Accordingly, the protrusion itself of the ACF  121  is reduced. 
     Next, the third embodiment of the present disclosure is explained with reference to  FIG.  7    through  FIG.  10   . 
       FIG.  7    is an explanatory diagram for a cross section of the head module according to the embodiment along the lateral direction of the head. 
       FIG.  8    and  FIG.  9    are explanatory diagrams for exploded perspective views of the head module. 
       FIG.  10    is an explanatory diagram for an exploded perspective view from the nozzle surface side of the head module. 
     The head module  100  includes the multiple heads  1  which are liquid discharge heads that discharge liquid, the base member  102 , the nozzle cover member  103  which is a nozzle cover, the heat-radiation member  104 , the manifold  105 , the printed circuit board  106  (PCB), and the module case  107 . 
     The heads  1  are circulation type heads, which include the nozzle plate  10  in which the nozzle  11  is formed, the individual channel plate  20  formed with the pressure chamber  21  leading to the nozzle  11 , etc., the diaphragm plate  30  including the piezoelectric element  40 , the intermediate channel plate  50  stacked on the diaphragm plate  30 , the common channel member  70  stacked on the intermediate channel plate  50 , etc. 
     Together with the pressure chamber  21 , the individual channel plate  20  forms the supply side individual channel  22  leading to the pressure chamber  21  and the collection side individual channel  24  leading to the pressure chamber  21 . 
     The intermediate channel plate  50  forms the supply side intermediate individual channel  51  leading to the supply side individual channel  22  via the opening  31  of the diaphragm plate  30  and the collection side intermediate individual channel  52  leading to the collection side individual channel  24  via the opening  32  of the diaphragm plate  30 . 
     The common channel member  70  forms the supply side common channel  71  leading to the supply side intermediate individual channel  51  and the collection side common channel  72  leading to the collection side intermediate individual channel  52 . The supply side common channel  71  leads to the supply port  81  via the channel  151  of the manifold  105 . The collection side common channel  72  leads to the collection port  82  via the channel  152  of the manifold  105 . 
     The printed circuit board  106  and the piezoelectric element  40  are connected via the flexible wiring  90 , and a driver integrated circuit  91  (driver IC) is mounted on the flexible wiring  90 . The driver IC  91  is also referred to as a drive circuit. The driver IC  91  is thermally coupled to the heat-radiation member  104 . 
     The head  1  is inserted to the opening part  102   a  formed in the base member  102  and is fixed by bonding the peripheral end of the individual channel plate  20  to the cover member  103 , which is bonded and fixed to the base member  102 . Further, the attaching parts  70   a  formed in the common channel member  70  arc fixed to the base member  102  with screws. 
     In this head  1 , as with the above-described first embodiment or second embodiment, the flexible wiring  90  and a wiring electrode that is pulled out from the piezoelectric element  40  are bonded and connected with an ACF. Further, on the surface where the diaphragm plate  30  (insulating film) is provided on the individual channel plate  20  formed with a silicon substrate, the silicon exposed area where the insulating film is not provided exists around the area where the flexible wiring  90  and the electrode wiring are bonded via the ACF. 
     Next, an example of the apparatus that discharges liquid according to the present embodiments is explained with reference to  FIG.  11    and  FIG.  12   . 
       FIG.  11    is a schematic explanatory diagram of the apparatus. 
       FIG.  12    is a planar explanatory diagram of an example of a discharge unit of the apparatus. 
     The printing apparatus  500  is a liquid discharge apparatus that discharges a liquid. The printing apparatus  500  includes the installation unit  501  that installs the continuous body  510 , the guide/conveyance unit  503  that guides and conveys the continuous body  510  to the printing unit  505 , such as continuous paper or a continuous sheet provided by the installation unit  501 , the printing unit  505  that performs printing by discharging liquid to the continuous body  510  to form an image, the drying unit  507  that dries the continuous body  510 , the ejection unit  509  that ejects the continuous body  510 , etc. 
     The continuous body  510  is fed from the wound roller  511  of the installation unit  501 , guided and conveyed by the respective rollers of the installation unit  501 , the guide/conveyance unit  503 , the drying unit  507 , and the ejection unit  509 , and wounded by the winder roller  591  of the ejection unit  509 . 
     In the printing unit  505 , this continuous body  510  is conveyed in such a manner facing the discharge unit  550 , so that an image is printed with the liquid discharged from the discharge unit  550 . 
     As illustrated in  FIG.  12   , the discharge unit  550  includes the two head modules explained in the above-described third embodiment, i.e., the head module  100 A and head module  100 B, in the common holding member  300 . 
     Note that, with respect to the head arrangement direction, which is the direction in which the heads  1  are arranged in the head modules  100  and is the direction perpendicular to the conveyance direction, the head rows  1 A 1  and  1 A 2  of the head module  100 A discharge liquid of the same color. Similarly, the head rows  1 B 1  and  1 B 2  of the head module  100 A are paired, the head rows  1 C 1  and  1 C 2  of the head module  100 B are paired, and the head rows  1 D 1  and  1 D 2  are paired, to discharge liquid of the respective colors as desired. 
     Note that the head modules according to the present embodiments can be integrated with functional components and mechanisms, to configure the liquid discharge unit. For example, the head modules can be combined with at least one of a head tank, carriage, supply mechanism, maintenance/recovery mechanism, main-scanning movement mechanism, and configurations of a liquid circulation apparatus. 
     Here, the term “integrate” includes, for example, that a head module and functional components or mechanisms are fastened, bonded, engaged, etc., to be fixed to each other or so that one is held with the other in a movable manner. Further, the head module and the functional components or mechanisms may be configured to be removable from each other. 
     Further, the “apparatus that discharges liquid” in the present embodiments includes an apparatus including a head, head module, or liquid discharge unit, to discharge liquid by driving the liquid discharge head. 
     The apparatus that discharges liquid includes, not only an apparatus that can discharge liquid to an object to which liquid can be attached, but also an apparatus that discharges liquid into gas or liquid. 
     The “apparatus that discharges liquid” can include a means relating to the feeding, conveying, and ejecting of an object to which liquid can be attached, and, moreover, a pre-processing apparatus, a post-processing apparatus, and the like. 
     For example, the “apparatus that discharges liquid” may be an image forming apparatus, which is an apparatus that discharges ink to form an image on a sheet, or a stereoscopic modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto a powdery material layer, which is formed by layering powdery material, in order to produce a stereoscopic modeled object (three-dimensional modeled object). 
     Further, the “apparatus that discharges liquid” is not limited to an apparatus that discharges liquid for visualizing meaningful images such as letters and figures. For example, an apparatus that forms a pattern and the like that does not have meaning by itself and an apparatus that produces a three-dimensional model are included. 
     The above-mentioned “object to which liquid can be attached” is indicative of an object to which liquid can be attached at least temporarily, an object to which liquid can be attached and fixed, an object to which liquid can be attached and permeate, etc. Unless otherwise specified, anything that liquid can be attached to is included, and specific examples include media to be recorded such as sheets, record paper, record sheets, films, and cloths, electronic components such as electronic substrates and piezoelectric elements, and other media such as powdery material layers (powder layers), organ models, and cells for inspection. 
     The material of the aforementioned “object to which liquid can be attached” may be anything to which liquid can be attached at least temporarily, such as paper, yarn, fiber, fabric, leather, metals, plastics, glass, wood, and ceramics. 
     Further, although the “apparatus that discharges liquid” is an apparatus in which the liquid discharge head moves relative to the object to which liquid can be attached, there is not a limitation as such. Specific examples include a serial type apparatus which moves the liquid discharge head, a line type apparatus which does not move the liquid discharge head, etc. 
     Further, in addition, the “apparatus that discharges liquid” may be a processing liquid applying apparatus that discharges a processing liquid onto a sheet in order to apply the processing liquid onto the sheet surface for a purpose of improving the quality of the sheet surface, etc., a spray granulation apparatus that sprays a composition liquid having raw materials dispersed inside of the liquid through a nozzle to granulate fine particles of the raw material, etc. 
     Although the liquid to be discharged is not limited in particular and can be anything that has a viscosity and a surface tension suitable for being discharged from the head, it is preferable to use a liquid whose viscosity becomes 30 mPa·s or less by heating or cooling under a normal temperature and normal pressure. More specifically, the liquid may be a solution, a suspension, an emulsion, or the like including a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalization material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acid, protein, or calcium, an edible material such as a natural colorant, etc., and, for example, these can be used for the purposes of an inkjet ink, a surface treatment solution, a liquid for forming a constituent element of an electronic element or a light-emitting element or a resist pattern of an electronic circuit, or a material solution for three-dimensional modeling. 
     The energy generating source for discharging liquid includes ones using a piezoelectric actuator (laminated type piezoelectric element or thin film type piezoelectric element), a thermal actuator which uses an electricity-heat conversion element such as a heating resistor, an electrostatic actuator configured with a diaphragm plate and counter electrodes, etc. 
     Note that, among the terms of the present application, terms such as image forming, recording, letter printing, photo printing, printing, and modeling are synonyms. According to the present embodiments, a protrusion of a conductive film can be easily detected. 
     [Aspect 1] 
     A head ( 1 ) includes: a silicon substrate ( 20 ); an insulating film ( 30 ) on the silicon substrate ( 20 ); an electrode wiring ( 146 ) on the insulating film ( 30 ); a flexible wiring ( 90 ) connected to the electrode wiring ( 146 ); and a conductive film ( 121 ) electrically connects the flexible wiring ( 90 ) and the electrode wiring ( 146 ) in a bonding area. The silicon substrate ( 20 ) has an exposed area ( 20   a ) on a surface of the silicon substrate ( 20 ) facing the insulating film ( 30 ), and the exposed area ( 20   a ) is in a vicinity of the bonding area and is exposed from the insulating film ( 30 ). 
     [Aspect 2] 
     In the head ( 1 ) according to Aspect 1, the exposed area ( 20   a ) is at an end of the silicon substrate ( 20 ) closed to the flexible wiring ( 90 ). 
     [Aspect 3] 
     In the head ( 1 ) according to Aspect 1, the insulating film ( 30 ) has a rising part ( 30   a ) rising toward the electrode wiring ( 146 ) at an end surface of the electrode wiring ( 146 ). 
     [Aspect 4] 
     In the head ( 1 ) according to Aspect 3, the insulating film ( 30 ) further has a folding part ( 30   b ) connected to the rising part ( 30   a ) to cover a part of surface of the electrode wiring ( 146 ). 
     [Aspect 5] 
     In a head module ( 100 ) comprising the head ( 1 ) according to Aspect 1, the head ( 1 ) includes multiple heads ( 1 ). 
     [Aspect 6] 
     A liquid discharge apparatus ( 500 ) includes the head module ( 100 ) according to Aspect 5, wherein the head ( 1 ) discharges a liquid. 
     The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention.