Patent Publication Number: US-11040536-B2

Title: Liquid discharge head, liquid discharge device, and liquid discharge apparatus

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. 2018-222132, filed on Nov. 28, 2018 in the Japan Patent Office and Japanese Patent Application No. 2019-040741, filed on Mar. 6, 2019 in the Japan Patent Office, the entire disclosures of which are hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     Aspects of the present disclosure relate to a liquid discharge head, a liquid discharge device, and a liquid discharge apparatus. 
     Related Art 
     A liquid discharge head that discharges a liquid includes a common channel (common chamber) that communicates with a plurality of individual chambers (pressure chambers). 
     The liquid discharge head includes a plurality of partitions on a top surface opposite a bottom surface of the common chamber when a discharge direction of the liquid is toward the gravity direction, and the bottom surface is disposed lower side in the gravity direction. 
     SUMMARY 
     In an aspect of this disclosure, a liquid discharge head includes a plurality of nozzles from which a liquid is discharged in a gravity direction, a plurality of pressure chambers communicating with the plurality of nozzles, respectively, a common channel communicating with each of the plurality of pressure chambers, the common channel including a top surface and a bottom surface disposed below the top surface in the gravity direction, and a plurality of convex portions formed on the bottom surface of the common channel. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The aforementioned and other aspects, features, and advantages of the present disclosure will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a plan view of a liquid discharge head according to a first embodiment of the present disclosure illustrating a channel arrangement and configuration of the liquid discharge head; 
         FIG. 2  is a cross-sectional view of the liquid discharge head along a line A-A of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of a common-supply main channel in a longitudinal direction of the common-supply main channel along a line B-B in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of the common-supply main channel in a transverse direction of the common-supply main channel along a line C 1 -C 1  in  FIG. 1 ; 
         FIG. 5  is a plan view of the liquid discharge head according to a second embodiment of the present disclosure illustrating a channel arrangement and configuration of the liquid discharge head; 
         FIG. 6  is a cross-sectional view of the common-supply main channel in the transverse direction of the common-supply main channel along a line C 2 -C 2  in  FIG. 5 ; 
         FIG. 7  is a plan view of the liquid discharge head according to a third embodiment of the present disclosure illustrating a channel arrangement and configuration of the liquid discharge head; 
         FIG. 8  is a cross-sectional view of the common-supply main channel in the transverse direction of the common-supply main channel along a line C 3 -C 3  in  FIG. 7 ; 
         FIG. 9  is an outer perspective view of the liquid discharge head according to a fourth embodiment of the present disclosure; 
         FIG. 10  is an exploded perspective view of the liquid discharge head in the fourth embodiment; 
         FIG. 11  is an exploded perspective view of the liquid discharge head without a frame in the fourth embodiment; 
         FIG. 12  is a cross-sectional perspective view of channels in the liquid discharge head in the fourth embodiment; 
         FIG. 13  is an enlarged cross-sectional perspective view of the channels in the fourth embodiment; 
         FIG. 14  is a cross-sectional view of the common-supply main channel of the liquid discharge head according to a fifth embodiment of the present disclosure in the longitudinal direction of the common-supply main channel; 
         FIG. 15  is a plan view of the liquid discharge head according to a sixth embodiment of the present disclosure illustrating a channel arrangement and configuration of the liquid discharge head; 
         FIG. 16  is a cross-sectional view of the liquid discharge head according to the sixth embodiment of the present disclosure in a nozzle array direction of the liquid discharge head; 
         FIG. 17  is a cross-sectional view of the liquid discharge head along the nozzle array direction corresponding to a line D-D in  FIG. 16 ; 
         FIG. 18  is a cross-sectional view of the common channel member of the liquid discharge head along the nozzle array direction corresponding to a line E-E in  FIG. 16 ; 
         FIG. 19  is a plan view of a portion of a plate forming a bottom surface of the common-supply channel; 
         FIG. 20  is an exploded perspective view of a head module according to the present disclosure; 
         FIG. 21  is an exploded perspective view of the head module viewed from a nozzle surface side of the head module; 
         FIG. 22  is a schematic side view of a liquid discharge apparatus according to the present disclosure; 
         FIG. 23  is a plan view of a head device of the liquid discharge apparatus of  FIG. 22 ; 
         FIG. 24  is a plan view of a portion of a printer as a liquid discharge apparatus according to the present disclosure; 
         FIG. 25  is a schematic side view of a main portion of the liquid discharge apparatus; 
         FIG. 26  is a plan view of a portion of another example of a liquid discharge device; and 
         FIG. 27  is a front view of the liquid discharge device according to still another embodiment of the present disclosure. 
     
    
    
     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. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent 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 the same function, operate in a similar manner, and achieve similar results. 
     Although the embodiments are described with technical limitations with reference to the attached drawings, such description is not intended to limit the scope of the disclosure and all of the components or elements described in the embodiments of this disclosure are not necessarily indispensable. 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 described with reference to the attached drawings. A liquid discharge head according to an embodiment of the present disclosure is described with reference to  FIGS. 1 through 3 . 
     In the following, embodiments of the present disclosure is described with reference to the accompanying drawings. Next, a first embodiment of the present disclosure is described with reference to  FIGS. 1 and 2 .  FIG. 1  is a plan view of a liquid discharge head according to the first embodiment of the present disclosure.  FIG. 2  is a cross-sectional view of the liquid discharge head  1  along a line A-A of  FIG. 1 . 
     The liquid discharge head  1  includes a nozzle plate  10 , an individual channel member  20  (channel plate), a diaphragm member  30 , a piezoelectric element  40 , a common channel member  50 , and the like. Hereinafter, the liquid discharge head  1  is simply referred to as the “head  1 ”. 
     The nozzle plate  10  includes a plurality of nozzles  11  to discharge a liquid. The plurality of nozzles  11  are arranged in a two-dimensional matrix. 
     The individual channel member  20  includes a plurality of pressure chambers  21  (individual chambers) respectively communicating with the plurality of nozzles  11 , a plurality of individual-supply channels  22  respectively communicating with the plurality of pressure chambers  21 , and a plurality of individual-recovery channels  23  respectively communicating with the plurality of pressure chambers  21 . The individual-supply channel  22  includes a supply-side fluid restrictor  26 , and the individual-recovery channel  23  includes a recovery-side fluid restrictor  27 . 
     The diaphragm member  30  forms a diaphragm  31  serving as a deformable wall of the pressure chamber  21 , and the piezoelectric element  40  is formed on the diaphragm  31  to form a single body. Further, the diaphragm member  30  includes a supply opening  32  communicating with the individual-supply channel  22  and a recovery opening  33  communicating with the individual-recovery channel  23 . The piezoelectric element  40  is a pressure generator to deform the diaphragm  31  to pressurize the liquid in the pressure chamber  21 . 
     The common channel member  50  includes a plurality of common-supply branch channels  52  that communicate with two or more individual-supply channels  22  and a plurality of common-recovery branch channels  53  that communicate with two or more individual-recovery channels  23 . The plurality of common-supply branch channels  52  and the plurality of common-recovery branch channels  53  are arranged alternately adjacent to each other. 
     The common channel member  50  includes a supply port  54  and a recovery port  55 . The supply port  54  connects the supply opening  32  of the individual-supply channel  22  and the common-supply branch channel  52 . The recovery port  55  connects the recovery opening  33  of the individual-recovery channel  23  and the common-recovery branch channel  53 . 
     The common channel member  50  includes one or more common-supply main channels  56  (see  FIG. 1 ) that communicate with the plurality of common-supply branch channels  52 , and one or more common-recovery main channels  57  (see  FIG. 1 ) that communicate with the plurality of common-recovery branch channels  53 . The common-supply main channel  56  includes supply ports  71  connected to an external circulation device, and the common-recovery main channel  57  includes recovery ports  72  connected to the external circulation device. 
     The common-supply main channel  56 , the common-supply branch channels  52 , the common-recovery main channels  57 , and the common-recovery branch channels  53  are collectively referred to as a “common channel”. 
     The common-supply main channel  56  and the plurality of common-supply branch channels  52  form a common-supply channel. The common-recovery main channel  57  and the plurality of common-recovery branch channels  53  form a common-recovery channel. The common-supply channel and the common-recovery channel form the common channel. 
     Next, a configuration of the common channel in the first embodiment is described with reference to  FIGS. 3 and 4 .  FIG. 3  is a cross-sectional view of the common-supply main channel  56  in a longitudinal direction of the common-supply main channel  56  along a line B-B in  FIG. 1 . The longitudinal direction of the common-supply main channel  56  is indicated by arrow “LD” in  FIGS. 1, 3, and 4 . Also, a longitudinal direction of the pressure chamber  21  is indicated by arrow “LDP” in  FIGS. 1 and 2 . Further, a nozzle array direction along which the plurality of nozzles are arrayed is indicated by arrow “NAD” in  FIG. 1 .  FIG. 4  is a cross-sectional view of the common-supply main channel  56  in a transverse direction of the common-supply main channel  56  along a line C 1 -C 1  in  FIG. 1 .  FIGS. 3 and 4  illustrate an operation of a liquid flow in the common-supply main channel  56 . 
     The head  1  according to the present disclosure includes a plurality of convex portions  73  on a bottom surface  56   a  of the common-supply main channel  56 . Here, the bottom surface  56   a  is a surface of a wall of the common-supply main channel  56  disposed at lower side in a gravity direction as illustrated in  FIGS. 3 and 4  when a discharge direction of the liquid from the nozzle  11  is in the gravity direciton (directed downward) as illustrated in  FIG. 2 . 
     Here, the “gravity direction” is not limited to a direction along the gravity direction, but includes a direction having an inclination of less than 45° with respect to the gravity direction (an obliquely downward direction). 
     Here, the convex portions  73  are arranged in a central part in a transverse direction (width direction) of the common-supply main channel  56  as illustrated in  FIG. 4 . The transverse direciton of the common-supply main channel  56  is indicated by arrow “TD” in  FIGS. 1, 3, and 4 . The transverse direction TD is perpendicular to the longitudinal direction LD. 
     The convex portions  73  in the common-supply main channel  56  thus configured generate a difference in the flow rate of a liquid flowing through the common-supply main channel  56  when the liquid is supplied from the supply port  71  and flows through the common-supply main channel  56  in a direction as indicated by arrow  301  in  FIG. 3 . The difference in the flow rate generates vortexes  302  (including turbulence of flow of the liquid) in the common-supply main channel  56 . 
     Thus, the liquid containing sedimentation components  300  is efficiently stirred in the common-supply main channel  56 , and the sedimentation components  300  are rolled up. Thus, the convex portions  73  can prevent sedimentation of the sedimentation components  300  in the common-supply main channel  56 . 
     The common-supply main channel  56  includes both of a region with the convex portion  73  and a region without the convex portion  73  to generate the vortexes  302 . As illustrated in  FIG. 4 , a width w 1  of the convex portion  73  is preferably equal to or less than half of a channel width W 1  of the common-supply main channel  56  in a transverse direction TD of the common-supply main channel  56 . 
     Further, as illustrated in  FIG. 3 , if a height h 1  of the convex portion  73  is too high, an efficiency of stirring the sedimentation component is reduced. Thus, a height h 1  of the convex portion  73  is preferably equal to or less than half of a channel height H 1  of the common-supply main channel  56 . 
     The convex portions  73  may be formed by etching or the like. Further, although the convex portions  73  in  FIGS. 3 and 4  have a rectangular shape, the convex portions  73  may have a rectangular shape, a trapezoid shape, semicircular shape, semi-elliptical shape, and the like. 
     Further, the head  1  in the present disclosure includes convex portions  74  in the common-recovery main channel  57  as in the convex portions  73  in the common-supply main channel  56  as illustrated in  FIG. 1 . The arrangement, configuration, and the like of the convex portions  74  are the same as the arrangement, configuration, and the like of the convex portions  73 . Thus, the convex portions  74  can prevent sedimentation of the sedimentation component  300  contained in the liquid in the common-recovery main channel  57 . 
     A second embodiment of the present disclosure is described with reference to  FIGS. 5 and 6 .  FIG. 5  is a plan view of the head  1  according to the second embodiment illustrating a channel arrangement and configuration of the head  1 .  FIG. 6  is a cross-sectional view of the head  1  along a line C 2 -C 2  of  FIG. 5 . The cross-sectional view along the line B-B of the head  1  in  FIG. 5  is the same as the cross-sectional view of the head  1  in  FIG. 3 . 
     The convex portions  73  in the second embodiment formed on the bottom surface  56   a  of the common-supply main channel  56  is arranged to be biased toward one side of a first side wall  56   b  (see  FIG. 6 ) in the transverse direction TD of the common-supply main channel  56 . Specifically, one end (left end in  FIG. 6 ) of each of the convex portions  73  contacts the first side wall  56   b  of the common-supply main channel  56 , and another end of each of the convex portions  73  does not contact (has a space with) a second side wall  56   c  disposed opposite the first side wall  56   b  in the transverse direction TD. 
     Thus, one end of each of the plurality of convex portions  73  contacts the first side wall  56   b  of the common-supply main channel  56  in a transverse direction TD of the common-supply main channel  56 . Another end of each of the plurality of convex portions  73  separates from the second side wall  56   c  disposed opposite the first side wall  56   b , and the second side wall  56   c  is connected to each of the plurality of common-supply branch channels  52 . 
     The first side wall  56   b  to which the convex portions  73  contact (biased) is opposite the second side wall  56   c  to which the common-supply branch channels  52  are connected in the transverse direction TD. The convex portions  73  may be formed together with the first side wall  56   b  and the bottom surface  56   a  as a single body. 
     As in the first embodiment, the convex portions  73  in the common-supply main channel  56  thus configured generate a difference in the flow rate of a liquid flowing through the common-supply main channel  56  when the liquid is supplied from the supply port  71  and flows through the common-supply main channel  56  in a direction as indicated by arrow  301  in  FIG. 3 . The difference in the flow rate generates vortexes  302  (including turbulence of flow of the liquid) in the common-supply main channel  56 . 
     Thus, the liquid containing sedimentation components  300  is efficiently stirred in the common-supply main channel  56 , and the sedimentation components  300  are rolled up. Thus, the convex portions  73  can prevent sedimentation of the sedimentation components  300  in the common-supply main channel  56 . 
     Further, the head  1  in the present disclosure includes the convex portions  74  in the common-recovery main channel  57  as in the convex portions  73  in the common-supply main channel  56  as illustrated in  FIG. 5 . The arrangement, configuration, and the like of the convex portions  74  are the same as the arrangement, configuration, and the like of the convex portions  73 . Thus, the convex portions  74  can prevent sedimentation of the sedimentation component  300  contained in the liquid in the common-recovery main channel  57 . 
     A third embodiment of the present disclosure is described with reference to  FIGS. 7 and 8 .  FIG. 7  is a plan view of the head  1  according to the third embodiment illustrating a channel arrangement and configuration of the head  1 .  FIG. 8  is a cross-sectional view of the head  1  along a line C 3 -C 3  of  FIG. 7 . The cross-sectional view along the line B-B of the head  1  in  FIG. 7  is the same as the cross-sectional view of the head  1  in  FIG. 3 . 
     The convex portions  73  in the third embodiment formed on the bottom surface  56   a  of the common-supply main channel  56  is arranged to be biased toward each of the first side wall  56   b  and the second side wall  56   c  (see  FIGS. 7 and 8 ) in the transverse direction TD of the common-supply main channel  56 . Specifically, each of the convex portions  73  is divided into two parts (first part  73   a  and second part  73   b ). A first part  73   a  of the convex portion  73  contacts the first side wall  56   b , a second part  73   b  of the convex portion  73  contacts the second side wall  56   c , and there is a space between the first part  73   a  and the second part  73   b  of the convex portion  73  in a center of the bottom surface  56   a  in the transverse direction TD of the common-supply main channel  56 . 
     Thus, each of the plurality of convex portions  73  includes a first part  73   a  contacting the first side wall  56   b  of the common-supply main channel  56  in a transverse direction TD of the common-supply main channel  56 , and a second part  73   b  contacting a second side wall  56   c  of the common-supply main channel  56  opposite the first side wall  56   b  with a space between the first part  73   a.    
     As in the first embodiment, the convex portions  73  (first part  73   a  and second part  73   b ) in the common-supply main channel  56  thus configured generate a difference in the flow rate of a liquid flowing through the common-supply main channel  56  when the liquid is supplied from the supply port  71  and flows through the common-supply main channel  56  in the direction as indicated by arrow  301  in  FIG. 3 . The difference in the flow rate generates vortexes  302  (including turbulence of flow of the liquid) in the common-supply main channel  56 . 
     Thus, the liquid containing sedimentation components  300  is efficiently stirred in the common-supply main channel  56 , and the sedimentation components  300  are rolled up. Thus, the convex portions  73  can prevent sedimentation of the sedimentation components  300  in the common-supply main channel  56 . 
     Further, the head  1  in the present disclosure includes the convex portions  74  (first part  74   a  and second part  74   b ) in the common-recovery main channel  57  as in the convex portions  73  (first part  73   a  and second part  73   b ) in the common-supply main channel  56  as illustrated in  FIG. 7 . The arrangement, configuration, and the like of the convex portions  74  (first part  74   a  and second part  74   b ) are the same as the arrangement, configuration, and the like of the convex portions  73  (first part  73   a  and second part  73   b ). Thus, the convex portions  74  (first part  74   a  and second part  74   b ) can prevent sedimentation of the sedimentation component  300  contained in the liquid in the common-recovery main channel  57 . 
     Next, a fourth embodiment of the present disclosure is described with reference to  FIGS. 9 to 13 .  FIG. 9  is an outer perspective view of the head  1  according to the fourth embodiment.  FIG. 10  is an exploded perspective view of the head  1 .  FIG. 11  is an exploded perspective view of the head  1  excluding a frame.  FIG. 12  is a cross-sectional perspective view of channels of the head  1 .  FIG. 13  is an enlarged cross-sectional perspective view of the channels of the head  1 . 
     The head  1  includes a nozzle plate  10 , an individual channel member  20  (channel plate), a diaphragm member  30 , a common channel member  50 , a damper  60 , a frame  80 , and a flexible wiring  101  (substrate) mounting a drive circuit  102 . 
     The nozzle plate  10  includes a plurality of nozzles  11  to discharge a liquid. The plurality of nozzles  11  are arranged in a two-dimensional matrix. 
     The individual channel member  20  includes a plurality of pressure chambers  21  (individual chambers) respectively communicating with the plurality of nozzles  11 , a plurality of individual-supply channels  22  respectively communicating with the plurality of pressure chambers  21 , and a plurality of individual-recovery channels  23  respectively communicating with the plurality of pressure chambers  21 . A combination of one pressure chamber  21 , one individual-supply channel  22  communicating with one pressure chamber  21 , and one individual-recovery channel  23  communicating with one pressure chamber  21  is collectively referred to as an individual channel. 
     The diaphragm member  30  forms a diaphragm  31  serving as a deformable wall of the pressure chamber  21 , and the piezoelectric element  40  is formed on the diaphragm  31  to form a single body. Further, the diaphragm member  30  includes a supply opening  32  communicating with the individual-supply channel  22  and a recovery opening  33  communicating with the individual-recovery channel  23 . The piezoelectric element  40  is pressure generating means (driving element) that deforms the diaphragm  31  to pressurize the liquid in the pressure chamber  21 . 
     The common channel member  50  includes a plurality of common-supply branch channels  52  that communicate with two or more individual-supply channels  22  and a plurality of common-recovery branch channels  53  that communicate with two or more individual-recovery channels  23 . The plurality of common-supply branch channel  52  and the plurality of common-recovery branch channel  53  are alternately formed adjacent to each other in the longitudinal direction LD of the common-supply main channel  56  (see  FIGS. 11 and 12 ). 
     As illustrated in  FIGS. 12 and 13 , the common channel member  50  includes a through hole serving as a supply port  54  that connects the supply opening  32  of the individual-supply channel  22  and the common-supply branch channel  52  and a through hole serving as a recovery port  55  that connects the recovery opening  33  of the individual-recovery channel  23  and the common-recovery branch channel  53 . 
     The common channel member  50  includes one or more common-supply main channels  56  (see  FIG. 1 ) that communicate with the plurality of common-supply branch channels  52 , and one or more common-recovery main channels  57  (see  FIG. 1 ) that communicate with the plurality of common-recovery branch channels  53 . 
     As illustrated in  FIG. 11 , the damper  60  includes a supply-side damper  62  that faces (opposes) the supply port  54  of the common-supply branch channel  52  and a recovery-side damper  63  that faces (opposes) the recovery port  55  of the common-recovery branch channel  53 . 
     As illustrated in  FIGS. 11 to 13 , the common-supply branch channel  52  and the common-recovery branch channel  53  are formed by sealing grooves with the supply-side damper  62  and the recovery-side damper  63  of the damper  60 . The grooves are alternately arranged in the common channel member  50  in the longitudinal direction LD of the common-supply main channel  56 . Both of the common-supply branch channel  52  and the common-recovery branch channel  53  are formed in the same common channel member  50 . 
     The head  1  in the fourth embodiment also includes the convex portions  73  and  74  on the bottom surface  56   a  of the common-supply main channel  56  and the common-recovery main channel  57  in the same manner as in the first to third embodiments. Thus, the convex portions  73  and  74  can prevent sedimentation of the sedimentation component  300  contained in the liquid in the common-supply main channel  56  and the common-recovery main channel  57 . 
     A fifth embodiment of the present disclosure is described with reference to  FIG. 14 .  FIG. 14  is a cross-sectional view of the common-supply main channel  56  of the head  1  according to the fifth embodiment in the longitudinal direction LD of the common-supply main channel  56 . 
     The head  1  according to the fifth embodiment includes the convex portions  73  in the common-supply main channel  56 . A density of arrangement of the convex portions  73  in a portion away from the supply ports  71  is larger than a density of arrangement of the convex portions  73  in a portion near the supply ports  71  in the common-supply main channel  56 . 
     In  FIG. 14 , the supply ports  71  are connected to each ends of the common-supply main channel  56  in the transverse direction TD of the common-supply main channel  56 . A density of arrangement of the convex portions  73  arranged at a central portion of the common-supply main channel  56  in the transverse direction TD is made larger than a density of arrangement of the convex portions  73  arranged at an end portions of the common-supply main channel  56  in the transverse direction TD. Reducing an arrangement pitch between adjacent convex portions  73  or increasing the number of the convex portions  73  can increase the density of arrangement of the convex portions  73  at the central portion of the common-supply main channel  56  in the transverse direction TD. 
     Thus, the convex portions  73  can effectively stir the liquid on a downstream side of the supply port  71  at which an amount of flow of the liquid decreases. 
     A sixth embodiment of the present disclosure is described with reference to  FIG. 15 .  FIG. 15  is a plan view of the head  1  according to the sixth embodiment illustrating a channel arrangement and configuration of the head  1 . 
     The head  1  according to the sixth embodiment does not include the convex portions  73  at connection portions between the common-supply branch channels  52  and the common-supply main channel  56 . Conversely, the head  1  includes the convex portion  73  at portions other than the connection portions in the common-supply main channel  56 . 
     Thus, the common-supply main channel  56  includes the plurality of convex portions  73  at portions between connections at which the common-supply main channel  56  is connected to the plurality of common-supply branch channels  52 . 
     Similarly, the head  1  according to the sixth embodiment does not include the convex portions  74  at connection portions between the common-recovery branch channels  53  and the common-recovery main channel  57 . Conversely, the head  1  includes the convex portion  74  at portions other than the connection portions in the common-recovery main channel  57 . 
     Thus, the common-recovery main channel  57  includes the plurality of convex portions  74  at portions between connections at which the common-recovery main channel  57  is connected to the plurality of common-recovery branch channels  53 . 
     Thus, the convex portions  73  do not hinder a liquid flow (liquid supply) from the common-supply main channel  56  to the common-supply branch channel  52 . Further, the convex portions  74  do not hinder a liquid flow (liquid supply) from the common-recovery branch channel  53  to the common-supply main channel  57 . 
     A seventh embodiment of the present disclosure is described with reference to  FIGS. 16 and 17 .  FIG. 16  is a cross-sectional view of the head  1  according to the seventh embodiment along a longitudinal direction of a pressure chamber  206  indicated by arrow “LDP” in  FIG. 16 . The longitudinal direction LDP of the pressure chamber  206  is perpendicular to a nozzle array direction along which a plurality of nozzles  204  are arrayed. The nozzle array direciton is indicated by arrow “NAD” in  FIG. 17 .  FIG. 17  is a cross-sectional view of the head  1  of  FIG. 16  along the nozzle array direction NAD corresponding to a line D-D in  FIG. 16 . The nozzle array direction NAD indicated in  FIG. 1  has an inclination (angle) with the transverse direction TD of the common-supply main channel  56 . 
     The head  1  according to the seventh embodiment includes a nozzle plate  201 , a channel plate  202 , and a diaphragm  203  as a wall that are laminated one on another and bonded to each other. The head  1  further includes a piezoelectric actuator  211  that displaces the diaphragm  203  and a common channel member  220 . 
     The nozzle plate  201  includes the plurality of nozzles  204  to discharge a liquid. The channel plate  202  is a channel member that includes pressure chambers  206  (individual chambers), supply-side fluid restrictors  207 , and supply-side inlets  208 . The pressure chambers  206  communicate with the nozzles  204 , respectively. The supply-side fluid restrictors  207  communicate with the pressure chambers  206  (individual chambers), respectively. The supply-side inlets  208  communicate with the supply-side fluid restrictors  207 , respectively. The supply-side inlets  208  communicate with a common-supply channel  210  through a supply-side opening  209  formed in the diaphragm  31 . The common-supply channel  210  is formed in the common channel member  220 . 
     The diaphragm  203  forms a wall of the pressure chamber  206  of the channel plate  202 . The diaphragm  203  has a two-layer structure (can be three or more layers) and includes a first layer  203 A that forms a thin portion and a second layer  203 B that forms a thick portion from the channel plate  202  side. The first layer  203 A of the diaphragm  203  forms a deformable vibration portion  230  positioned corresponding to the pressure chambers  206  (individual chamber). 
     The head  1  includes a piezoelectric actuator  211  including an electromechanical transducer element as a driving device (actuator device or pressure generator) to deform a vibration portion  230  of the diaphragm  203  disposed at a fist side of the diaphragm  203  opposite a second side facing the pressure chambers  206  (individual chambers). 
     The piezoelectric actuator  211  includes piezoelectric members  212  bonded on a base  213 . The piezoelectric members  212  are groove-processed by half-cut dicing so that each piezoelectric members  212  includes a desired number of pillar-shaped piezoelectric elements  212 A and  212 B that are arranged in certain intervals to have a comb shape. 
     The piezoelectric elements  212 A of the piezoelectric member  212  are piezoelectric elements to be driven by application of drive waveforms and the piezoelectric elements  212 B are supports to which no drive waveform is applied. However, all of the piezoelectric elements  212 A and  212 B may be piezoelectric elements to be driven by application of drive waveforms. 
     The piezoelectric element  212 A is bonded to a convex portion  230   a  having an island-shaped thick portion on the vibration portion  230  of the diaphragm  203 . The piezoelectric element  212 B is bonded to a convex portion  230   b  that is a thick portion of the diaphragm  203 . 
     The piezoelectric member  212  includes piezoelectric layers and internal electrodes alternately laminated on each other. Each internal electrode is pulled out to an end surface of the piezoelectric member  212  to form an external electrode. The external electrode is connected to a flexible wiring member  215 . 
     The channel plate  202  includes recovery-side fluid restrictors  257 , recovery-side individual channels  256 , and recovery-side outlets  258 . The recovery-side fluid restrictors  257 , the recovery-side individual channels  256 , and the recovery-side outlets  258  are formed along a surface direction of the channel plate  202 , and communicate with the pressure chambers  206  (individual chambers). The recovery-side outlet  258  communicating with the common-recovery channel  250  formed by the common channel member  220  through the recovery-side opening  259  formed in the diaphragm  203 . 
     Connection channels  205  connect the pressure chambers  206 , nozzles  204 , and recovery-side fluid restrictors  257 , respectively. The connection channels  205  face the nozzles  204  respectively. 
     The common channel member  220  defines a common-supply channel  210  and a common-recovery channel  250 . The common channel member  220  further includes a supply port  271  to supply the liquid from an external circulation path to the common-supply channel  210  and a recovery port  272  to recover the liquid to the external circulation path (see  FIG. 18 ). 
     The common-supply channel  210  includes a first channel portion  210 A arranged side-by-side with the common-recovery channel  250  in a direction perpendicular to the nozzle array direction NAD (in the longitudinal direction LDP of the pressure chamber  206 ). Further, the channel portion  210 B, which is a part of the common-supply channel  210 , is arranged above the first channel portion  210 A and the common-recovery channel  250  in a gravity direction and is not aligned with the common-recovery channel  250  in the direction perpendicular to the nozzle array direction NAD (in the longitudinal direction LDP). The gravity direction is identical to the “discharge direction” as indicated by arrow in  FIG. 2 . 
     In the head  1  thus configured, for example, when a voltage lower than a reference potential is applied to the piezoelectric element  212 A, the piezoelectric element  212 A contracts. Accordingly, the vibration portion  230  of the diaphragm  203  moves upward in  FIGS. 16 and 17  and the volume of the pressure chamber  206  increases, thus causing liquid to flow into the pressure chamber  206 . 
     When the voltage applied to the piezoelectric element  212 A is raised, the piezoelectric element  212 A expands in a direction of lamination of the piezoelectric element  212 A. The vibration portion  230  of the diaphragm  203  deforms in a direction toward the nozzle  204  and contracts the volume of the pressure chambers  206 . As a result, the liquid in the pressure chambers  206  is squeezed out of the nozzle  204 . 
     When the voltage applied to the piezoelectric element  212 A is returned to the reference potential, the vibration portion  230  of the diaphragm  203  is returned to the initial position. Accordingly, the pressure chamber  206  expands to generate a negative pressure, thus replenishing liquid from the common-supply channel  210  into the pressure chamber  206 . After the vibration of a meniscus surface of the liquid in the nozzle  204  decays to a stable state, the head  1  shifts to a next liquid discharge operation. 
     Further, the liquid not discharged from the nozzle  204  passes the nozzle  204  and is discharged to the common-recovery channel  250  through the recovery-side fluid restrictor  257 , the recovery-side individual channel  256 , the recovery-side outlet  258 , and the recovery-side opening  259 . Then, the liquid is supplied from the common-recovery channel  250  to the common-supply channel  210  again through an external circulation passage. Even when the liquid is not discharged from the nozzle  204 , the liquid flows from the common-supply channel  210  to the common-recovery channel  250  and is again supplied to the common-supply channel  210  through the external circulation passage. 
     Note that the driving method of the head  1  is not limited to the above-described example (pull-push discharge). For example, pull discharge or push discharge may be performed in accordance with the way to apply a drive waveform. 
     Next, a configuration of the common channel member  220  in the head according to the seventh embodiment is described with reference to  FIGS. 18 and 19 .  FIG. 18  is a cross-sectional view of the head  1  of  FIG. 16  along the nozzle array direction NAD corresponding to a line D-D in  FIG. 16 .  FIG. 19  is a plan view of a portion of a plate forming a bottom surface of the common-supply channel  210 . 
     The common channel member  220  includes a first common channel member  221  and a second common channel member  222 . The first common channel member  221  includes a first channel portion  210 A and the common-recovery channel  250 . The second common channel member  222  includes a second channel portion  210 B that is a part of the common-supply channel  210 . 
     Further, the second common channel member  222  includes a supply port  271  communicating with the second channel portion  210 B that is a part of the common-supply channel  210 . 
     In the head  1  according to the seventh embodiment, the first common channel member  221  includes lamination of a plurality of plates  221 A to  221 I (plate-like members). In  FIG. 18 , nine plates  221 A to  221 I are laminated to form the first common channel member  221 . The plates  221 H and  222 I among the plurality of plates  221 A to  221 I of the first common channel member  221  forms a partition wall  240  between the second channel portion  210 B of the common-supply channel  210  and the common-recovery channel  250 . The partition wall  240  forms a bottom surface of the second channel portion  210 B. 
     The plate  221 I disposed at the second channel portion  210 B side is one of the plurality of plates  221 H and  221 I that forms the partition wall  240  between the second channel portion  210 B of the common-supply channel  210  and the common-recovery channel  250 . As illustrated in  FIG. 19 , a plurality of slits  224  are formed in the plate  221 I at regions that becomes a bottom surface of the second channel portion  210 B of the common-supply channel  210 . The plate  221 I includes a through-hole  223  that forms the first channel portion  210 A that is a part of the common-supply channel  210 . 
     Walls  225  formed between a plurality of slits  224  in the plate  221 I forms the convex portions  273  as illustrated in  FIGS. 18 and 19 . That is, the plurality of slits  224  are arranged such that the walls  225  between the plurality of slits  224  forms the convex portions  273 . 
     Thus, the plurality of convex portions  273  can be easily formed on a bottom surface of the second channel portion  210 B of the common-supply channel  210 . 
       FIGS. 20 and 21  illustrate an example of a head module according to an embodiment of the present disclosure.  FIG. 20  is an exploded perspective view of a head module  100 .  FIG. 21  is an exploded perspective view of the head module  100  viewed from a nozzle surface side of the head module  100 . 
     The head module  100  includes a plurality of heads  1  as described above, a base  103  that holds the plurality of heads  1 , and a cover  113  that serves as a nozzle cover of the plurality of heads  1 . 
     Further, the head module  100  includes a heat radiator  104 , a manifold  105  forming a channel to supply liquid to the plurality of heads  1 , a printed circuit board  106  (PCB) connected to a flexible wiring  101 , and a module case  107 . 
       FIGS. 22 and 23  illustrate an example of a liquid discharge apparatus according to the present disclosure.  FIG. 22  is a side view of a liquid discharge apparatus according to the present disclosure.  FIG. 23  is a plan view of a head unit  550  of the liquid discharge apparatus of  FIG. 22  according to the present disclosure. 
     A printer  500  serving as the liquid discharge apparatus includes a feeder  501  to feed a continuous medium  510 , such as a rolled sheet, a guide conveyor  503  to guide and convey the continuous medium  510 , fed from the feeder  501 , to a printing unit  505 , the printing unit  505  to discharge a liquid onto the continuous medium  510  to form an image on the continuous medium  510 , a drier unit  507  to dry the continuous medium  510 , and an ejector  509  to eject the continuous medium  510 . 
     The continuous medium  510  is fed from a winding roller  511  of the feeder  501 , guided and conveyed with rollers of the feeder  501 , the guide conveyor  503 , the drier unit  507 , and wound around a take-up roller  591  of the ejector  509 . 
     The continuous medium  510  is conveyed by the printing unit  505  so as to face the head unit  550 , and an image is printed by the liquid ejected from the head unit  550 . 
     Here, as illustrated in  FIG. 23 , the head unit  550  includes two head modules  100 A and  100 B according to the present disclosure on a common base  552 . 
     The head module  100 A includes head arrays  1 A 1 ,  1 B 1 ,  1 A 2 , and  1 B 2 . Each of the head arrays  1 A 1 ,  1 B 1 ,  1 A 2 , and  1 B 2  includes a plurality of heads  1  arranged in a direction perpendicular to a conveyance direction of the continuous medium  510 . The direction perpendicular to the conveyance direction of the continuous medium  510  is also referred to as a “head array direction” indicated by arrow “HAD” in  FIG. 23 . The head module  100 B includes head arrays  1 C 1 ,  1 D 1 ,  1 C 2 , and  1 D 2 . 
     Each of the head arrays  1 C 1 ,  1 D 1 ,  1 C 2 , and  1 D 2  includes a plurality of heads  1  arranged in the head array direction HAD. The head  1  in each of the head arrays  1 A 1  and  1 A 2  of the head module  100 A discharges liquid of the same color. Similarly, the head arrays  1 B 1  and  1 B 2  of the head module  100 A are grouped as one set that discharge liquid of the same color. The head arrays  1 C 1  and  1 C 2  of the head module  100 B are grouped as one set that discharge liquid of the same color. The head arrays  1 D 1  and  1 D 2  are grouped as one set to discharge liquid of the same color. 
     Next, another example of a printer  500  serving as a liquid discharge apparatus according to the present disclosure is described with reference to  FIGS. 24 and 25 .  FIG. 24  is a plan view of a portion of the printer  500 .  FIG. 25  is a side view of a portion of the printer  500  of  FIG. 24 . 
     The printer  500  is a serial type apparatus, and the carriage  403  is reciprocally moved in the main scanning direction MSD by the main scan moving unit  493 . The main scanning moving unit  493  includes a guide  401 , a main scanning motor  405 , a timing belt  408 , and the like. The guide  401  is bridged between a left-side plate  491 A and a right-side plate  491 B to moveably hold the carriage  403 . The main scanning motor  405  reciprocally moves the carriage  403  in the main scanning direction MSD via the timing belt  408  bridged between a driving pulley  406  and a driven pulley  407 . 
     The carriage  403  mounts a liquid discharge device  440 . The head  1  according to the present disclosure and a head tank  441  forms the liquid discharge device  440  as a single unit. The head  1  of the liquid discharge device  440  discharges liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The head  1  includes a nozzle array including a plurality of nozzles  11  arrayed in a sub-scanning direction indicated by arrow “SSD” perpendicular to the main scanning direction indicated by arrow “MSD” in  FIG. 24 . The head  1  is mounted to the carriage  403  so that ink droplets are discharged downward. 
     The printer  500  includes a conveyor  495  to convey a sheet  410 . The conveyor  495  includes a conveyance belt  412  as a conveyor and a sub-scanning motor  416  to drive the conveyance belt  412 . 
     The conveyance belt  412  attracts the sheet  410  and conveys the sheet  410  at a position facing the head  1 . The conveyance belt  412  is an endless belt and is stretched between a conveyance roller  413  and a tension roller  414 . Attraction of the sheet  410  to the conveyance belt  412  may be applied by electrostatic adsorption, air suction, or the like. 
     The conveyance belt  412  cyclically rotates in the sub-scanning direction SSD as the conveyance roller  413  is rotationally driven by the sub-scanning motor  416  via the timing belt  417  and the timing pulley  418 . 
     At one side in the main scanning direction MSD of the carriage  403 , a maintenance unit  420  to maintain the head  1  in good condition is disposed on a lateral side of the conveyance belt  412 . 
     The maintenance unit  420  includes, for example, a cap  421  to cap the nozzle surface of the head  1  and a wiper  422  to wipe the nozzle surface of the head  1 . 
     The main scan moving unit  493 , the maintenance unit  420 , and the conveyor  495  are mounted to a housing that includes a left-side plate  491 A, a right-side plate  491 B, and a rear-side plate  491 C. 
     In the printer  500  thus configured, the sheet  410  is conveyed on and attracted to the conveyance belt  412  and is conveyed in the sub-scanning direction SSD by the cyclic rotation of the conveyance belt  412 . 
     The head  1  is driven in response to image signals while the carriage  403  moves in the main scanning direction MSD, to discharge liquid to the sheet  410  stopped, thus forming an image on the sheet  410 . 
     Next, the liquid discharge device  440  according to another embodiment of the present disclosure is described with reference to  FIG. 26 .  FIG. 26  is a plan view of a portion of another example of the liquid discharge device  440 . 
     The liquid discharge device  440  includes a housing, the main scan moving unit  493 , the carriage  403 , and the head  1  among components of the printer  500  (liquid discharge apparatus). The left-side plate  491 A, the right-side plate  491 B, and the rear-side plate  491 C constitute the housing. 
     Note that, in the liquid discharge device  440 , the maintenance unit  420  described above may be mounted on, for example, the right-side plate  491 B. 
     Next, still another example of the liquid discharge device  440  according to the present disclosure is described with reference to  FIG. 27 .  FIG. 27  is a front view of still another example of the liquid discharge device  440 . 
     The liquid discharge device  440  includes the head  1 , to which a channel part  444  is attached, and a tube  456  connected to the channel part  444 . 
     Further, the channel part  444  is disposed inside a cover  442 . Instead of the channel part  444 , the liquid discharge device  440  may include a head tank  441 . A connector  443  electrically connected with the head  1  is provided on an upper part of the channel part  444 . 
     In the present disclosure, discharged liquid is not limited to a particular liquid as long as the liquid has a viscosity or surface tension to be discharged from a head (liquid discharge head). However, preferably, the viscosity of the liquid is not greater than 30 mPa·s under ordinary temperature and ordinary pressure or by heating or cooling. 
     Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, or a surfactant, a biocompatible material, such as DNA, amino acid, protein, or calcium, or an edible material, such as a natural colorant. 
     Such a solution, a suspension, or an emulsion can be used for, e.g., inkjet ink, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, or a material solution for three-dimensional fabrication. 
     Examples of an energy source to generate energy to discharge liquid include a piezoelectric actuator (a laminated piezoelectric element or a thin-film piezoelectric element), a thermal actuator that employs a thermoelectric conversion element, such as a heating resistor, and an electrostatic actuator including a diaphragm and opposed electrodes. 
     The “liquid discharge device” is an assembly of parts relating to liquid discharge. The term “liquid discharge device” represents a structure including the head and a functional part(s) or mechanism combined to the head to form a single unit. For example, the “liquid discharge device” includes a combination of the head with at least one of a head tank, a carriage, a supply unit, a maintenance unit, a main scan moving unit, and a liquid circulation apparatus. 
     Here, examples of the “single unit” include a combination in which the head and a functional part(s) or unit(s) are secured to each other through, e.g., fastening, bonding, or engaging, and a combination in which one of the head and a functional part(s) or unit(s) is movably held by another. The head may be detachably attached to the functional part(s) or unit(s) s each other. 
     For example, the head and the head tank may form the liquid discharge device as a single unit. Alternatively, the head and the head tank coupled (connected) with a tube or the like may form the liquid discharge device as a single unit. Here, a unit including a filter may further be added to a portion between the head tank and the head. 
     In another example, the head and the carriage may form the liquid discharge device as a single unit. 
     In still another example, the liquid discharge device includes the head movably held by a guide that forms part of a main scan moving unit, so that the head and the main scan moving unit form a single unit. The liquid discharge device may include the head, the carriage, and the main scan moving unit that form a single unit. 
     In still another example, a cap that forms part of a maintenance unit may be secured to the carriage mounting the head so that the head, the carriage, and the maintenance unit form a single unit to form the liquid discharge device. 
     Further, in another example, the liquid discharge device includes tubes connected to the head to which the head tank or the channel member is attached so that the head and a supply unit form a single unit. Liquid is supplied from a liquid reservoir source to the head via the tube. 
     The main scan moving unit may be a guide only. The supply unit may be a tube(s) only or a loading unit only. 
     In another example, the “liquid discharge device” may be a single unit in which the head and other functional parts are combined with each other. The “liquid discharge device” includes a head module including the above-described head, and a head device in which the above-described functional components and mechanisms are combined to form a single unit. 
     The term “liquid discharge apparatus” used herein also represents an apparatus including the head, the liquid discharge device, the head module, and the head device to discharge liquid by driving the head. The liquid discharge apparatus may be, for example, an apparatus capable of discharging liquid to a material to which liquid can adhere or an apparatus to discharge liquid toward gas or into liquid. 
     The “liquid discharge apparatus” may include devices to feed, convey, and eject the material on which liquid can adhere. The liquid discharge apparatus may further include a pretreatment apparatus to coat a treatment liquid onto the material, and a post-treatment apparatus to coat a treatment liquid onto the material, onto which the liquid has been discharged. 
     The “liquid discharge apparatus” may be, for example, an image forming apparatus to form an image on a sheet by discharging ink, or a three-dimensional fabrication apparatus to discharge a fabrication liquid to a powder layer in which powder material is formed in layers to form a three-dimensional fabrication object. 
     The “liquid discharge apparatus” is not limited to an apparatus to discharge liquid to visualize meaningful images, such as letters or figures. For example, the liquid discharge apparatus may be an apparatus to form arbitrary images, such as arbitrary patterns, or fabricate three-dimensional images. 
     The above-described term “material on which liquid can be adhered” represents a material on which liquid is at least temporarily adhered, a material on which liquid is adhered and fixed, or a material into which liquid is adhered to permeate. Examples of the “material on which liquid can be adhered” include recording media such as a paper sheet, recording paper, and a recording sheet of paper, film, and cloth, electronic components such as an electronic substrate and a piezoelectric element, and media such as a powder layer, an organ model, and a testing cell. The “material on which liquid can be adhered” includes any material on which liquid adheres unless particularly limited. 
     Examples of the “material on which liquid can be adhered” include any materials on which liquid can be adhered even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic. 
     The “liquid discharge apparatus” may be an apparatus to relatively move the head and a material on which liquid can be adhered. However, the liquid discharge apparatus is not limited to such an apparatus. For example, the liquid discharge apparatus may be a serial head apparatus that moves the head or a line head apparatus that does not move the head. 
     Examples of the “liquid discharge apparatus” further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet to coat the treatment liquid on the surface of the sheet to reform the sheet surface, and an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is injected through nozzles to granulate fine particles of the raw materials. 
     The terms “image formation”, “recording”, “printing”, “image printing”, and “fabricating” used herein may be used synonymously with each other. 
     Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that, within the scope of the above teachings, the present disclosure may be practiced otherwise than as specifically described herein. With some embodiments having thus been described, it is obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the present disclosure and appended claims, and all such modifications are intended to be included within the scope of the present disclosure and appended claims.