Patent Publication Number: US-11046082-B2

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

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation application of U.S. application Ser. No. 15/787,226, filed Oct. 18, 2017, which is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2016-225482, filed on Nov. 18, 2016, in the Japan Patent Office and Japanese Patent Application No. 2017-168184, filed on Sep. 1, 2017, in the Japan Patent Office. The entire disclosures of each of the above are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Technical Field 
     Aspects of this disclosure relate to a liquid discharge head, a liquid discharge device, a liquid supply member, and a liquid discharge apparatus. 
     Related Art 
     A liquid discharge head includes a liquid supply member having a liquid supply channel for supplying liquid to a common liquid chamber of a head main body of the liquid discharge head. 
     For example, the liquid discharge head includes the liquid supply channel interposed between an ink tank and the head main body of the liquid discharge head. The liquid supply member is formed by connecting an upper part of a connection channel and a lower part of the connection channel via an elastic member (sheet gasket). The elastic member forms a wall of a portion of the liquid supply channel formed along a nozzle face. 
     SUMMARY 
     In an aspect of this disclosure, a novel liquid discharge head includes a plurality of nozzles to discharge liquid, a plurality of individual liquid chambers communicating with the plurality of nozzles, respectively, a common liquid chamber to supply the liquid to the plurality of individual liquid chambers, and a liquid supply member including a liquid supply channel to supply the liquid to the common liquid chamber. The liquid supply member includes a first member including a part of the liquid supply channel, a second member including a gas chamber, and an elastic member disposed between the first member and the second member and forming a wall of the liquid supply channel of the first member and a wall of the gas chamber of the second member. The gas chamber of the second member is disposed opposite the liquid supply channel of the first member via the elastic member. 
     In another aspect of this disclosure, a liquid discharge head includes a common-chamber member including a common liquid chamber to supply liquid to a plurality of individual liquid chambers communicating respectively with a plurality of nozzles, from which the liquid is discharged, a liquid supply member including a liquid supply channel to supply the liquid to the common liquid chamber, and an elastic member disposed between the common-chamber member and the liquid supply member and forming a wall of the common liquid chamber. The liquid supply member includes a gas chamber disposed opposite the common liquid chamber via the elastic member. 
     In still another aspect of this disclosure, a liquid supply member includes a liquid supply channel connected to a common liquid chamber formed in a liquid discharge head that includes a plurality of nozzles to discharge liquid. The liquid supply member includes a first member including a part of the liquid supply channel, and a second member including a gas chamber. An elastic member is disposed between the first member and the second member, the elastic member forming a wall of the liquid supply channel of the first member and a wall of the gas chamber of the second member. The gas chamber of the second member is disposed opposite the liquid supply channel of the first member via the elastic member. 
    
    
     
       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 perspective view of a liquid discharge head according to a first embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional view of the liquid discharge head along a direction along a nozzle array direction (longitudinal direction of common liquid chamber); 
         FIG. 3  is an enlarged cross-sectional view of a head main body of the liquid discharge head; 
         FIG. 4  is a cross-sectional view of the liquid discharge head along the nozzle array direction (longitudinal direction of common liquid chamber) according to a second embodiment of the present disclosure; 
         FIG. 5  is an enlarged cross-sectional view of a channel portion of the liquid discharge head along a direction perpendicular to the nozzle array direction (transverse direction of common liquid chamber); 
         FIG. 6  is a perspective view of an example of a head main body; 
         FIG. 7  is a cross-sectional view of the head main body along the direction perpendicular to the nozzle array direction; 
         FIG. 8  is an enlarged cross-sectional view of a portion of the head main body of  FIG. 7 ; 
         FIG. 9  is a cross-sectional view of a portion of the head main body along the nozzle array direction; 
         FIG. 10  is a perspective view of the liquid supply member according to a third embodiment of the present disclosure; 
         FIG. 11  is a perspective view of a first member as a lower case seen from the upper surface side of the first member; 
         FIG. 12  is a perspective view of the first member seen from a lower surface side of the first member; 
         FIG. 13  is a plan view of the first member; 
         FIG. 14  is a perspective view of the first member in a state in which an elastic member is disposed on the first member; 
         FIG. 15  is a plan view of the first member in the state in which the elastic member is disposed on the first member; 
         FIG. 16  is a perspective view of the second member as an upper case as viewed from the first member side; 
         FIG. 17  is a cross-sectional view of a liquid supply channel of a liquid supply member connected to the head main body; 
         FIG. 18  is a cross-sectional view of the liquid discharge head according to a fourth embodiment of the present disclosure along the nozzle array direction (longitudinal direction of the individual liquid chamber); 
         FIG. 19  is a plan view of a portion of a liquid discharge apparatus according to embodiments of the present disclosure; 
         FIG. 20  is a side view of a portion of the liquid discharge apparatus; 
         FIG. 21  is a plan view of a portion of a liquid discharge device; and 
         FIG. 22  is a front view of another example of the liquid discharge device. 
     
    
    
     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. 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, embodiments of the present disclosure are described below. 
     Below, embodiments of the present disclosure are described with reference to the attached drawings. 
       FIGS. 1 to 3  illustrate a liquid discharge head  404  according to a first embodiment of the present disclosure. 
       FIG. 1  is a perspective view of the liquid discharge head  404  according to the first embodiment of the present disclosure. 
       FIG. 2  is a cross-sectional view of the liquid discharge head  404  of  FIG. 1  along a direction along a nozzle array direction (longitudinal direction of common liquid chamber) in which nozzles are arrayed in row. 
       FIG. 3  is an enlarged cross-sectional view of a main body of the liquid discharge head  404  of  FIG. 2 . 
     The liquid discharge head  404  includes a head main body  100  and a liquid supply member  200 . The head main body  100  includes a nozzle face  1   a  in which a plurality of nozzles  4  to discharge liquid is formed. The liquid supply member  200  includes a liquid supply channel  201  communicating with a common liquid chamber  10  inside the head main body  100  to supply liquid to the head main body  100 . 
     As illustrated in  FIG. 3 , the head main body  100  includes a nozzle plate  1 , an actuator substrate  20 , a common-chamber substrate  70 , and a damper  90 . Nozzles  4  are formed in the nozzle plate  1 . The actuator substrate  20  includes an individual channel and a pressure-generating element (pressure generator). The common-chamber substrate  70  forms common liquid chamber  10 . The damper  90  forms a wall of the common liquid chamber  10 . A side of the damper  90  opposite the common liquid chamber  10  forms a damper chamber  95 . 
     The common-chamber substrate  70  includes a connection channel  71  communicating with the common liquid chamber  10 . The connection channel  71  communicates with liquid supply channel  201  of the liquid supply member  200 . 
     As illustrated in  FIG. 2 , the liquid supply member  200  includes a first member  211  disposed on the head main body  100  side, an elastic member  213 , and a second member  212  fixed to the first member  211  via the elastic member  213 . 
     The second member  212  includes a vertical channel  201 A that forms a part of the liquid supply channel  201 . The vertical channel  201 A is formed by a through-hole penetrating the second member  212  in a direction perpendicular to the surface of the nozzle face  1   a . A connecting portion  214  is provided at an entrance side of the vertical channel  201 A. The connecting portion  214  is connected to an external liquid storage directly or via a supply tube. 
     The first member  211  includes a vertical channel  201 C as a second channel that forms a part of the liquid supply channel  201 . The vertical channel  201 C is formed by a through-hole penetrating the first member  211  in a direction perpendicular to the surface of the nozzle face  1   a . The first member  211  further includes a lateral channel  201 B served as a first channel that forms a part of the liquid supply channel  201 . The lateral channel  201 B is a recess formed along the nozzle face  1   a.    
     The lateral channel  201 B connects the vertical channel  201 A with the vertical channel  201 C. An upstream of the lateral channel  201 B communicates with the vertical channel  201 A and a downstream of the lateral channel  201 B communicates with the vertical channel  201 C. Thus, the liquid flows from the connecting portion  214  to the head main body  100  through the vertical channel  201 A, the lateral channel  201 B, and the vertical channel  201 C in a liquid direction of flow. 
     A wall of the lateral channel  201 B of the first member  211  on the second member  212  side is formed by the elastic member  213 . The portion of the elastic member  213  forming the wall of the lateral channel  201 B becomes a damper  209 . The elastic member  213  includes a channel  201 D formed with a through-hole that communicates the vertical channel  201 A of the second member  212  with the lateral channel  201 B of the first member  211 . This elastic member  213  also serves as a sealing member for sealing a portion between the first member  211  and the second member  212  by a sheet gasket. 
     Here, in a state where the elastic member  213  is sandwiched between the first member  211  and the second member  212 , the first member  211  and the second member  212  are fixed to each other by a fixing member such as a screw or a bolt. Thus, the elastic member  213  is pressed between the first member  211  and the second member  212 . 
     As illustrated in  FIG. 2 , bolts  206  that serve as a fixing member are inserted into fixing holes  205  (See  FIGS. 11 to 16 ) to fix the first member  211  and the second member  212 . The bolts  206  sandwich and press the elastic member  213  between the first member  211  and the second member  212  to fix (join) the first member  211  and the second member  212  together. 
     Further, the second member  212  is provided with a gas chamber  215  as a damper chamber on the opposite side of the lateral channel  201 B of the first member  211  via a portion of the damper  209  of the elastic member  213 . 
     Due to such a configuration, a part of the pressure fluctuation transmitted to the common liquid chamber  10  attendant upon a liquid discharge operation and not absorbed by the damper  90  propagates to the liquid supply channel  201 . Then, the pressure fluctuation is absorbed or suppressed by the damper  209  of the elastic member  213  constituting the wall of the lateral channel  201 B. 
     Therefore, the present embodiment can absorb or suppress the pressure fluctuation more efficiently than the configuration that includes the damper  90  in the common liquid chamber  10 . Thereby, the present embodiment can perform stable liquid discharge operation. 
     Further, the elastic member  213  serves as a seal member for sealing between the first member  211  and the second member  212  and also serves as a damper forming a wall of a part of the liquid supply channel  201 . Thereby, the present embodiment can reduce the number of parts due to providing the damper in the liquid supply channel  201 . 
     A second embodiment according to the present disclosure is described with reference to  FIGS. 4 and 5 .  FIG. 4  is a cross-sectional view of the liquid discharge head  404  along a direction along a nozzle array direction (NAD, a longitudinal direction of common liquid chamber) in which nozzles  4  are arrayed in rows.  FIG. 5  is an enlarged cross-sectional view of a channel portion of the liquid discharge head  404  along a direction perpendicular to the nozzle array direction (NAD) (transverse direction of common liquid chamber) in which nozzles are arrayed in rows. 
     As illustrated in  FIG. 5 , the thickness t 1  of the damper  209  in a portion that forms the wall of the lateral channel  201 B is made thinner than the thickness t 2  of the other portion of the elastic member  213 . A part of the elastic member  213  that faces the lateral channel  201 B and the gas chamber  215  serves as the damper  209 . 
     As a result, while the elastic member  213  reliably seals the space between the first member  211  and the second member  212 , greater displacement is possible in the lateral channel  201 B, thereby improving the damper function. 
     An example of the head main body is described with reference to  FIGS. 6 to 9 .  FIG. 6  is a perspective view of the head main body  100 .  FIG. 7  is a cross-sectional view of the head main body  100  along the direction perpendicular to the nozzle array direction (NAD).  FIG. 8  is an enlarged cross-sectional view of a portion of the head body of  FIG. 7 .  FIG. 9  is a cross-sectional view of a portion of the head main body  100  along the nozzle array direction (NAD). 
     The head main body  100  includes a nozzle plate  1 , a channel plate  2 , a diaphragm  3 , piezoelectric elements  11 , a holding substrate  50 , a wiring member  60 , a common-chamber substrate  70 , and a cover  45 . The diaphragm  3  forms a wall of an individual liquid chamber  6 . The piezoelectric elements  11  serves as the pressure-generating elements (pressure generators). The wiring member  60  includes a flexible printed circuit (FPC). 
     Here, an actuator substrate  20  includes a part constituted by the channel plate  2 , the diaphragm  3 , and the piezoelectric element  11 . 
     The nozzle plate  1  includes a plurality of nozzles  4  to discharge liquid. As illustrated in  FIG. 7 , the nozzles  4  are arrayed in four rows to form four nozzle arrays. 
     With the nozzle plate  1  and the diaphragm  3 , the channel plate  2  forms individual liquid chambers  6  communicated with the nozzles  4 , fluid restrictors  7  communicated with the individual liquid chambers  6 , and liquid introduction portions  8  communicated with the fluid restrictors  7 . 
     The liquid introduction portions  8  are communicated with the common liquid chamber  10  formed by the common-chamber substrate  70  via slot  9  of the diaphragm  3  and an opening  51  served as a channel of the holding substrate  50 . 
     The diaphragm  3  includes deformable vibration portions  30  forming part of wall of the individual liquid chambers  6 . The piezoelectric element  11  is disposed integrally with the vibration portion  30  on a face of the vibration portion  30  of the diaphragm  3  opposite the individual liquid chamber  6 . The vibration portion  30  and the piezoelectric element  11  form a piezoelectric actuator. 
     In the piezoelectric element  11 , a lower electrode  13 , a piezoelectric layer (piezoelectric body)  12 , and an upper electrode  14  are laminated in this order from the vibration portion  30 . An insulation film  21  is formed on the piezoelectric element  11 . 
     The lower electrode  13  as a common electrode for the plurality of piezoelectric elements  11  is connected to a common-electrode power-supply wiring pattern  28  via a common wire  15 . The lower electrode  13  is a single electrode layer formed across entire of the piezoelectric elements  11  in the nozzle array direction (NAD). 
     The upper electrodes  14  as individual electrodes for the piezoelectric elements  11  are connected to a drive integrated circuit (IC)  500  (hereinafter, driver IC  500 ) as a drive circuit via individual wires  16 . The individual wire  16  is covered with an insulation film  22 . 
     The driver IC  500  is mounted on the actuator substrate  20  by a flip-chip bonding method, for example, to cover an area between rows of the piezoelectric elements  11 . 
     The driver IC  500  mounted on the actuator substrate  20  is connected to an individual-electrode power-supply wiring pattern  29  to which a drive waveform (drive signal) is supplied. 
     One end of a wire provided at the wiring member  60  is electrically connected to the driver IC  500 . Another end of the wiring member  60  is connected to a controller of an apparatus body. 
     The holding substrate  50  covering the piezoelectric element  11  on the actuator substrate  20  is bonded, with adhesive, to one side of the actuator substrate  20  on which the diaphragm  3  is disposed. 
     The holding substrate  50  includes openings  51 , recesses  52 , and openings  53 . The openings  51  serves as a part of channel that communicates the common liquid chambers  10  with the individual liquid chambers  6 . The recesses  52  accommodate the piezoelectric elements  11 . The openings  53  accommodate the driver IC  500  disposed on the actuator substrate  20 . The openings  51  are slit-shaped through-holes extending along the nozzle array direction NAD. The openings  51  forms a part of the common liquid chamber  10 . 
     The holding substrate  50  is interposed between the actuator substrate  20  and the common-chamber substrate  70  to form a wall of the common liquid chamber  10 . 
     The common-chamber substrate  70  forms the common liquid chamber  10  that supplies the liquid to each of the individual liquid chambers  6 . Note that, in the present embodiment, the four common liquid chambers  10  are disposed corresponding to the four nozzle arrays. Desired colors of liquids are supplied to the respective common liquid chambers  10  via the connection channels  71  communicating with the liquid supply member  200 . 
     A damper  90  is bonded to the common-chamber substrate  70 . The damper  90  includes a damper  91  and damper plates  92 . The damper  91  is deformable and forms part of wall of the common liquid chamber  10 . The damper plates  92  reinforce the damper  91 . The damper  90  forms a wall of the common liquid chamber  10 . 
     The common-chamber substrate  70  is bonded to the holding substrate  50  and an outer peripheral portion of the nozzle plate  1  with adhesive. The common-chamber substrate  70  accommodates the actuator substrate  20  and the holding substrate  50 , thus forming a frame of this liquid discharge head  404 . 
     Covers  45  are disposed to cover part of a peripheral are of the nozzle plate  1  and part of outer circumferential faces of the common-chamber substrate  70 . 
     In this head main body  100 , voltage is applied from the driver IC  500  to a portion between the upper electrode  14  and the lower electrode  13  of the piezoelectric element  11 . Accordingly, the piezoelectric layer  12  expands in an electrode lamination direction (in other words, an electric-field direction) in which the upper electrode  14  and the lower electrode  13  are laminated, and contracts in a direction parallel to the vibration portion  30 . Thus, tensile stress arises at a lower electrode  13  side of the vibration portion  30  facing the lower electrode  13 . This tensile stress causes the vibration portion  30  to bend toward an individual liquid chamber  6  side of the vibration portion  30  facing the individual liquid chamber  6 . Accordingly, liquid within the individual liquid chamber  6  is pressurized and discharged from the nozzle  4 . 
     Next, a liquid supply member according to a third embodiment of the present disclosure is described with reference to  FIGS. 10 to 17 . 
       FIG. 10  is a perspective view of the liquid supply member  200  according to the present embodiment. 
       FIG. 11  is a perspective view of the first member  211  as a lower case as viewed from the upper surface side of the first member  211 . 
       FIG. 12  is a perspective view of the first member  211  as viewed from the lower surface side of the first member  211 . 
       FIG. 13  is a plan view of the first member  211 . 
       FIG. 14  is a perspective view of the first member  211  in a state in which the elastic member  213  is disposed on the first member  211 . 
       FIG. 15  is a plan view of the first member  211  in a state in which the elastic member  213  is disposed on the first member  211 . 
       FIG. 16  is a perspective view of the second member  212  as the upper case as viewed from the first member  211  side. 
       FIG. 17  is a cross-sectional view of the liquid supply member  200  taken along a plane S of  FIG. 10  that is along the liquid direction of flow in the vertical channels  201 A and  201 C connected to the head main body  100 . 
     As illustrated in  FIG. 11 , on the upper surface of the first member  211 , a plurality of (here, four) channels, that is, lateral channel  201 B are formed so as to creep on the upper surface of the first member  211 . The lateral channel  201 B includes a bent portion  201 B a . The bent portion  201 B a  changes a direction of flow of the liquid in the middle of the lateral channel  201 B formed along a direction of the nozzle face  1   a . Thus, the first channel (lateral channel  201 B) includes the bent portion  201 B a  that changes a direction of flow of the liquid in the liquid supply channel  201  along the direction of the nozzle face  1   a.    
     In the plurality of lateral channels  201 B, convex ribs  216  are formed at the peripheral portions of each lateral channels  201 B so as to surround the lateral channels  201 B. 
     As illustrated in  FIG. 13 , one end of the lateral channel  201 B of the first member  211  is arranged at a narrow pitch (interval) so as to communicate with the connection channel  71  of the head main body  100 . The vertical channel  201 C is arranged in this one end of the lateral channel  201 B to communicate with the lateral channel  201 B. 
     On the other hand, another end of the lateral channel  201 B is wound around the upper surface of the first member  211  with a wider interval (pitch) between the lateral channels  201 B than the interval (pitch) of one end of the lateral channel  201 B. Thus, the other end of the lateral channel  201 B matches a position communicating with an outlet of the vertical channel  201 A of the second member  212  as an upper case. 
     A packing  213 A, which is a sheet-like elastic member, is disposed across the plurality of lateral channels  201 B of the first member  211 . The packing  213 A forms a wall of the plurality of lateral channels  201 B including the bent portion  201 B a . By covering the plurality of lateral channels  201 B with a single packing  213 A, it is possible to easily cover all the lateral channels  201 B including the bent portion  201 B a  when the lateral channel  201 B includes the bent portion  201 B a.    
     As illustrated in  FIGS. 14 and 15 , in the packing  213 A, the channels  201 D are arranged with a wide pitch (interval). The channels  201 D are formed by through-holes for communicating the vertical channel  201 A of the second member  212  with the lateral channel  201 B of the first member  211 . 
     The packing  213 A has a minimum size that covers the convex rib  216  formed to surround one lateral channel  201 B. Instead of one sheet-like packing  213 A, a plurality of packings covering each of the lateral channels  201 B may be arranged on the surface of the first member  211 . 
     As illustrated in  FIGS. 16 and 17 , a vertical channel  201 A is formed in the second member  212 . Ribs  217  surrounding the peripheral area of the vertical channels  201 A are formed on the packing  213 A side of the surface of the vertical channel  201 A of the second member  212 . Further, a recessed portion that becomes the gas chamber  215  is formed in the second member  212 . The recessed portion has an inverted form of the lateral channel  201 B The rib  217  surrounding the peripheral area of the gas chamber  215  is formed on a surface of the second member  212 . 
     Thus, the packing  213 A is sandwiched and crushed between the convex rib  216  of the first member  211  and the rib  217  of the second member  212  to reliably seal the space between the first member  211  and the second member  212 . 
     The liquid supply member  200  as described above is configured by fixing the first member  211  and the second member  212  with a fastening member while sandwiching the packing  213 A with the first member  211  and the second member  212  to become a state as illustrated in  FIG. 10 . 
     At this time, the convex rib  216  of the first member  211  and the rib  217  of the second member  212  crush the packing  213 A for a specified amount to seal the space between the first member  211  and the second member  212 . The packing  213 A serves as an elastic member. The packing  213 A seals the lateral channels  201 B to divide the lateral channels  201 B into respective sections. 
     As a result, the wall of the lateral channel  201 B on the second member  212  side is formed by the packing  213 A served as an elastic member. 
     Therefore, excessive pressure or pressure propagation, for example, existed in the lateral channel  201 B is absorbed by deformation of the packing  213 A served as an elastic wall. In this case, the deformation of the packing  213 A is suppressed by the second member  212  and the damper effect may not be reliably exhibited without the gas chamber  215 . 
     In each of the above-described embodiments, an example in which a part of a liquid supply channel  201  of the liquid supply member  200  is formed by the second member  212  is described. However, the second member  212  may have a configuration in which the liquid supply channel  201  of the liquid supply member  200  is not formed in the second member  212 . 
     A fourth embodiment according to the present disclosure is described with reference to  FIG. 18 .  FIG. 18  is a cross-sectional view of a main part of the liquid discharge head  404  along the nozzle array direction (NAD, longitudinal direction of the individual liquid chamber) according to the fourth embodiment. 
     The liquid discharge head  404  includes the common-chamber substrate  70  and a liquid supply member  75 . The common-chamber substrate  70  forms the common liquid chamber  10  that supplies the liquid to a plurality of the individual liquid chambers  6 . The plurality of individual liquid chambers  6  respectively communicates with the plurality of nozzles  4 , from which the liquid is discharged. The liquid supply member  75  forms a liquid supply path  72  that supplies the liquid to the common liquid chamber  10 . 
     The liquid discharge head  404  further includes an elastic member  313  that is pressed between the common-chamber substrate  70  and the liquid supply member  75 . The elastic member  313  forms a wall of the common liquid chamber  10 . The liquid discharge head  404  includes a gas chamber  96  disposed on an opposite side of the common liquid chamber  10  via the elastic member  313 . 
     Further, the elastic member  313  serves as a seal member for sealing between the common-chamber substrate  70  and the liquid supply member  75  and also serves as a damper forming a wall of the common liquid chamber  10 . Thereby, the present embodiment can reduce the number of parts due to providing the damper in the liquid discharge head  404 . 
       FIGS. 19 and 20  illustrate an example of a liquid discharge apparatus  600  according to the present embodiment.  FIG. 19  is a plan view of a main part of the liquid discharge apparatus  600 .  FIG. 20  is a side view of a portion of the liquid discharge apparatus  600 . 
     The liquid discharge apparatus  600  is a serial-type apparatus in which a main scan moving unit  493  reciprocally moves a carriage  403  in a main scanning direction indicated by arrow MSD in  FIG. 19 . The main scan moving unit  493  includes a guide  401 , a main scanning motor  405 , a timing belt  408 , etc. The guide  401  is laterally bridged between a left side plate  491 A and a right side plate  491 B. The guide  401  supports the carriage  403  so that the carriage  403  is movable along the guide  401 . The main scanning motor  405  reciprocally moves the carriage  403  in the main scanning direction MSD via the timing belt  408  laterally bridged between a drive pulley  406  and a driven pulley  407 . 
     The carriage  403  mounts a liquid discharge device  440  in which the liquid discharge head  404  according to the present embodiment and a head tank  441  are integrated as a single unit. The liquid discharge head  404  of the liquid discharge device  440  discharges color liquids of, for example, yellow (Y), cyan (C), magenta (M), and black (K). 
     The liquid discharge head  404  includes nozzle arrays, each including a plurality of nozzles  4  arrayed in row in a sub-scanning direction indicated by arrow SSD in  FIGS. 19 and 20 . The sub-scanning direction (SSD) is perpendicular to the main scanning direction MSD. The liquid discharge head  404  is mounted to the carriage  403  so that ink droplets are discharged downward. 
     The liquid stored outside the liquid discharge head  404  is supplied to the liquid discharge head  404  via a supply unit  494  that supplies the liquid from a liquid cartridge  450  to the head tank  441 . 
     The supply unit  494  includes, e.g., a cartridge holder  451  as a mount part to mount a liquid cartridge  450 , a tube  456 , and a liquid feed unit  452  including a liquid feed pump. The liquid cartridge  450  is detachably attached to the cartridge holder  451 . The liquid is supplied to the head tank  441  by the liquid feed unit  452  via the tube  456  from the liquid cartridge  450 . 
     The liquid discharge apparatus  600  includes a conveyance unit  495  to convey a sheet  410 . The conveyance unit  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 liquid discharge head  404 . The conveyance belt  412  is in the form of an endless belt. The conveyance belt  412  is stretched between a conveyance roller  413  and a tension roller  414 . The sheet  410  is attracted to the conveyance belt  412  by electrostatic force or air suction. 
     The conveyance roller  413  is rotated by a sub-scanning motor  416  via a timing belt  417  and a timing pulley  418 , so that the conveyance belt  412  circulates in a sub-scanning direction indicated by arrow SSD in  FIGS. 19 and 20 . 
     At one side in the main scanning direction MSD of the carriage  403 , a maintenance device  420  to recover the liquid discharge head  404  in good condition is disposed on a lateral side (right-hand side) of the conveyance belt  412  in  FIG. 19 . 
     The maintenance device  420  includes, for example, a cap  421  to cap a nozzle face (i.e., a face on which the nozzles are formed)  1   a  of the liquid discharge head  404  and a wiper  422  to wipe the nozzle face. 
     The main scan moving unit  493 , the supply unit  494 , the maintenance device  420 , and the conveyance unit  495  are mounted to a housing  491  that includes the left side plate  491 A, the right side plate  491 B, and a rear side plate  491 C. 
     In the liquid discharge apparatus  600  thus configured, a 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 liquid discharge head  404  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 . 
     As described above, the liquid discharge apparatus  600  includes the liquid discharge head  404  according to the present embodiment, thus allowing stable formation of high quality images. 
       FIG. 21  illustrates another example of the liquid discharge device  440 A according to an embodiment of the present disclosure.  FIG. 21  is a plan view of a main part of the liquid discharge device  440 A. 
     The liquid discharge device  440 A includes the housing  491 , the main scan moving unit  493 , the carriage  403 , and the liquid discharge head  404  among components of the liquid discharge apparatus  600 . The left side plate  491 A, the right side plate  491 B, and the rear side plate  491 C constitute the housing  491 . 
     Note that, in the liquid discharge device  440 A, at least one of the maintenance device  420  and the supply unit  494  described above may be mounted on, for example, the right side plate  491 B. 
       FIG. 22  illustrates still another example of the liquid discharge device  440 B according to an embodiment of the present disclosure.  FIG. 22  is a front view of the liquid discharge device  440 B. 
     The liquid discharge device  440 B includes the liquid discharge head  404  to which a channel part  444  is mounted, and the 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 B may include the head tank  441 . A connector  443  to electrically connect the liquid discharge head  404  to a power source is disposed above 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. 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 including, 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, and 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 for generating 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 (element), and an electrostatic actuator including a diaphragm and opposed electrodes. 
     “The liquid discharge device” is an integrated unit including the liquid discharge head and a functional part(s) or unit(s), and is an assembly of parts relating to liquid discharge. For example, “the liquid discharge device” may be a combination of the liquid discharge head with at least one of a head tank, a carriage, a supply unit, a maintenance device, and a main scan moving unit. 
     Herein, the terms “integrated” or “united” mean fixing the liquid discharge head and the functional parts (or mechanism) to each other by fastening, screwing, binding, or engaging and holding one of the liquid discharge head and the functional parts movably relative to the other. The liquid discharge head may be detachably attached to the functional part(s) or unit(s) s each other. 
     For example, the liquid discharge head and a head tank are integrated as the liquid discharge device. The liquid discharge head and the head tank may be connected each other via, e.g., a tube to integrally form the liquid discharge device. Here, a unit including a filter may further be added to a portion between the head tank and the liquid discharge head. 
     The liquid discharge device may be an integrated unit in which a liquid discharge head is integrated with a carriage. 
     The liquid discharge device may be the liquid discharge head movably held by a guide that forms part of a main scan moving unit, so that the liquid discharge head and the main scan moving unit are integrated as a single unit. The liquid discharge device may include the liquid discharge head, the carriage, and the main scan moving unit that are integrated as a single unit. 
     In another example, the cap that forms part of the maintenance device is secured to the carriage mounting the liquid discharge head so that the liquid discharge head, the carriage, and the maintenance device are integrated as a single unit to form the liquid discharge device. 
     Further, the liquid discharge device may include tubes connected to the liquid discharge head mounted on the head tank or the channel member so that the liquid discharge head and the supply assembly are integrated as a single unit. Liquid is supplied from a liquid reservoir source such as liquid cartridge to the liquid discharge head through the tube. 
     The main scan moving unit may be a guide only. The supply unit may be a tube(s) only or a mount part (loading unit) only. 
     The term “liquid discharge apparatus” used herein also represents an apparatus including the liquid discharge head or the liquid discharge device to discharge liquid by driving the liquid discharge 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, on 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 fabricating apparatus to discharge a fabrication liquid to a powder layer in which powder material is formed in layers, so as to form a three-dimensional fabrication object. 
     In addition, “the liquid discharge apparatus” is not limited to such an apparatus to form and visualize meaningful images, such as letters or figures, with discharged liquid. For example, the liquid discharge apparatus may be an apparatus to form meaningless images, such as meaningless 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 “medium on which liquid can be adhered” include recording media, such as paper sheet, recording paper, recording sheet of paper, film, and cloth, electronic component, such as electronic substrate and piezoelectric element, and media, such as powder layer, organ model, and testing cell. The “medium on which liquid can be adhered” includes any medium on which liquid is adhered, 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 a liquid discharge head and a medium 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 liquid discharge head or a line head apparatus that does not move the liquid discharge head. 
     Examples of the liquid discharge apparatus further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet surface to coat the sheet surface with the treatment liquid to reform the sheet surface and an injection granulation apparatus to eject a composition liquid including a raw material dispersed in a solution from a nozzle to mold particles of the raw material. 
     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.