Patent Publication Number: US-2023134389-A1

Title: Head, head module, liquid discharge apparatus, printer, module, and 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. 2021-180704, filed on Nov. 4, 2021, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     Embodiments of this disclosure relate to a head, head module, liquid discharge apparatus, printer, module, and apparatus. 
     Related Art 
     To configure a head module (also referred to as a head unit, head array, etc.), multiple liquid discharge heads are attached to a base member (holder), for example. 
     For example, there is a head including a through hole to which a screw of a fixation screw is inserted and a seat part with which a screw head of the fixation screw is brought into contact. The fixation screw is inserted to the through hole and screwed to a female screw of a support member so that the head is fixed to the support member. 
     SUMMARY 
     A head includes: an attachment attached to a holder with a screw, the attachment having a through hole to which the screw is inserted, and the through hole having: a female screw having a valley and a crest; and a first concave having a diameter larger than a diameter of the valley of the female screw, the first concave opening toward the holder. 
     A head module includes: a holder; a head attached to the holder; and a screw fixing the head to the holder. The head includes: an attachment having a through hole to which the screw is inserted, the through hole includes: a female screw having a valley and a crest; and a first concave having a diameter larger than a diameter of the valley of the female screw, the first concave opening toward the holder, and the screw includes: a screw head; a male screw at a tip of the screw; and a shaft between the screw head and the male screw and narrower than a diameter of the crest of the female screw. 
     A module includes: a first member; a second member; and a screw fixing the first member to the second member. The first member includes: an attachment having a through hole to which the screw is inserted, the through hole includes: a female screw having a valley and a crest; and a first concave having a diameter larger than a diameter of the valley of the female screw, the first concave opening toward the second member, and the screw includes: a screw head; a male screw at a tip of the screw; and a shaft between the screw head and the male screw and narrower than a diameter of the crest of the female screw. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein: 
         FIG.  1    is an explanatory diagram of a head a head module according to the first embodiment of the present embodiment along the longitudinal direction of the head; 
         FIG.  2    is an explanatory diagram of an external perspective view of an example of the head; 
         FIG.  3 A  to  FIG.  3 C  are explanatory diagrams of the head; 
         FIG.  4    is an explanatory diagram for a cross section of an attachment of the head in the embodiment; 
         FIG.  5    is an explanatory diagram for a cross section of a part of an attachment mechanism for the head and a holder corresponding to the A part of  FIG.  1   ; 
         FIG.  6 A  and  FIG.  6 B  are explanatory diagrams for a cross section in a state where a screw is attached to a through hole of the head, which is provided for the explanation of the function of the embodiment; 
         FIG.  7    is also an explanatory diagram for a cross section in a state where the head is placed on the holder; 
         FIG.  8    is an explanatory diagram for a cross section, which is provided for the explanation of the comparative example 1; 
         FIG.  9    is an explanatory diagram for a cross section of an attachment of the head according to the second embodiment of the present embodiment; 
         FIG.  10    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head and the holder in the head module according to the embodiment; 
         FIG.  11    is an explanatory diagram of the head module of the third embodiment of the present embodiment along the longitudinal direction of the head; 
         FIG.  12    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head and the holder corresponding to the B part of  FIG.  11   ; 
         FIG.  13    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head and the holder in the head module according to the fourth embodiment of the present embodiment; 
         FIG.  14    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head and the holder in the head and head module according to the fifth embodiment of the present embodiment; 
         FIG.  15    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head and the holder in the head and head module according to the sixth embodiment of the present embodiment; 
         FIG.  16    is an explanatory diagram for an external perspective view of the head according to the seventh embodiment of the present embodiment; 
         FIG.  17 A  to  FIG.  17 C  are explanatory diagrams of the head; 
         FIG.  18    is a planar explanatory diagram of the head module according to the eighth embodiment of the present embodiment; 
         FIG.  19    is a planar explanatory diagram of the head module according to the ninth embodiment of the present embodiment; 
         FIG.  20    is an explanatory diagram for a cross section of the head module of the tenth embodiment of the present embodiment along the lateral direction of the head; 
         FIG.  21    is an explanatory diagram for an exploded perspective view of the head module; 
         FIG.  22    is an explanatory diagram for an exploded perspective view of the head module; 
         FIG.  23    is an explanatory diagram for an exploded perspective view from the nozzle surface side of the head module; 
         FIG.  24    is a schematic explanatory diagram of an example of the liquid discharge apparatus according to the present embodiment; and 
         FIG.  25    is a planar explanatory diagram of an example of the discharge unit of the apparatus. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present invention and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result. 
     Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Hereinafter, an explanation will be given of the embodiments of the present embodiment with reference to the accompanying drawings. 
     The first embodiment of the present embodiment is described below with reference to  FIG.  1    through  FIG.  3 C . 
       FIG.  1    is an explanatory diagram of a head and head module  100  according to the embodiment along the longitudinal direction of the head. 
       FIG.  2    is an explanatory diagram of an external perspective view of an example of a head  200 . 
       FIG.  3 A  to  FIG.  3 C  are explanatory diagrams of the head  200 . 
     The head module  100  as the module includes the head  200 , i.e., one or more (only one of the head  200  is illustrated in the drawing) first members, which are liquid discharge heads  200  that discharge liquid, and the holder  300 , i.e., the second member such as a mounting plate to which the head  200  is attached. 
     The head  200  includes the base  201  and the cover  202 . 
     The base  201  includes the nozzle plate  10  in which the nozzles  11  are formed, an individual channel member (actuator substrate) including an individual channel plate formed with pressure chambers and the like leading to the nozzles  11  and a diaphragm plate integrally formed with piezoelectric elements, a common channel member formed as a common channel leading to the multiple pressure chambers, etc. 
     The cover  202  covers the port member  218  that supplies the liquid to the base  201 . 
     The connector part  221 , to which a wiring member for the piezoelectric elements is connected, is disposed on the upper part of the cover  202 . 
     The base  201  includes the attachments  230  as flanges at both ends in the longitudinal direction. 
     The holder  300  includes the opening  301  with which the head  200  is engaged. 
     Further, the base  201  of the head  200  is engaged with the opening  301  of the holder  300 , and the head  200  is fixed and attached to the holder  300  with the screws  400  inserted to the attachments  230  of the head  200 . 
     Next, the attachment mechanism for the head and the holder in the head module  100  according to the first embodiment is described below with reference to  FIG.  4    and  FIG.  5   . 
       FIG.  4    is an explanatory diagram for a cross section of an attachment  230  of the head  200 . 
       FIG.  5    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  corresponding to the A part of  FIG.  1   . 
     The attachment  230  of the head  200  includes the through hole  231  to which the screw  400  is inserted. The through hole  231  includes the female screw  232 , into which the screw  400  can be screwed, and the first concave  233  (hole part), which opens toward the holder  300  side. The first concave  233  has a diameter “b” that is larger than the diameter “a” of a valley of the female screw  232  (a &gt; b). The holder  300  side is the downstream side (forward side) in the insertion direction of the screw  400 . The female screw  232  has the valley and a crest. 
     Note that, in the present embodiment, the section other than the female screw  232  in the through hole  231  is the first concave  233 . Further, although the through hole  231  has a round hole shape in the present embodiment, the through hole  231  is not limited to a round hole and may have a polygonal shape. 
     The holder  300  includes the female screw  302  into which the screw  400  is screwed. 
     The female screw  232  of the head  200  and the female screw  302  of the holder  300  have the same screw shape. Note that, as long as the screw  400  can be screwed to pass through the female screw  232  of the head  200 , the female screw  232  need not have the same shape as the female screw  302  of the holder  300 . 
     Regarding the screw  400 , a male screw  402  is formed only at the tip part of the shaft  401 . Regarding the shaft  401 , the outer diameter c of the section having no screw below the screw head  403  to the male screw  402  is smaller than the diameter a of the valley of the female screw  232  of the head  200  (c &lt; a). Accordingly, the shaft  401  of the screw  400  can pass through the female screw  232  of the head  200 . 
     The shaft  401  has a diameter smaller than the diameter a of the crest of the female screw  232  of the head  200  (c &lt; f) as illustrated in  FIG.  5   . The diameter c of the valley of the female screw  232  is an outer diameter of the female screw  232 . The diameter f of the crest of the female screw  232  is an inner diameter of the female screw  232 . 
     The depth (height) d from the surface of the first concave  233  of the head  200  is longer than the length e of the male screw  402  of the screw  400  (d &gt; e). 
     Next, the function of the present embodiment is described below with reference to  FIG.  6 A  through  FIG.  8    as well.  FIG.  6 A  and  FIG.  6 B  are explanatory diagrams for a cross section in a state where a screw is attached to a through hole of the head, and  FIG.  7    is an explanatory diagram for a cross section in a state where the head is placed on the holder.  FIG.  8    is an explanatory diagram for a cross section, which is provided for the explanation of the comparative example 1. 
     When the head  200  is fixed and attached to the holder  300 , the screw  400  is inserted to the through hole  231  of the head  200  in advance. Here, as illustrated in  FIG.  6 A , the male screw  402  of the screw  400  is screwed to the female screw  232  of the through hole  231 . 
     Alternatively, as illustrated in  FIG.  6 B , the male screw  402  of the screw  400  is screwed to pass through the female screw  232  of the through hole  231 . 
     Further, the head  200  is placed on the holder  300  and the male screw  402  of the screw  400  is screwed to the female screw  302  of the holder  300  and fixed, so that the head  200  is attached on the holder  300 . 
     In this way, the screw  400  for fixation to the head  200  is screwed to the female screw  232  of the through hole  231  or passes through the through hole  231  and cannot be pulled out because of the female screw  232 , the screw  400  is prevented from falling out of the head  200 . 
     Accordingly, the workability of the work of attaching the head  200  to the holder  300  with the screw  400  is improved. 
     Here, the through hole  231  of the head  200  includes the first concave  233  that opens toward the holder  300  side, and the depth d of the first concave  233  is longer than the length e of the male screw  402  of the screw  400 . 
     Accordingly, since the male screw  402  is accommodated inside the first concave  233  when the head  200  is placed on the holder  300  and the male screw  402  of the screw  400  has passed through the female screw  232  of the through hole  231 , the head  200  is prevented from being lifted up, and thus the workability is improved. 
     On the other hand, in a case where the through hole  231  does not have the first concave that opens toward the holder  300  side as in the comparative example 1 illustrated in  FIG.  8   , the screw  400  move in a direction opposite to the holder  300  when the male screw  402  of the screw  400  has passed through the female screw  232  of the through hole  231 . Therefore, the head  200  is lifted up against the holder  300  in an unstable manner, which reduces workability. 
     Next, the second embodiment of the present embodiment is described below with reference to  FIG.  9    and  FIG.  10   . 
       FIG.  9    is an explanatory diagram for a cross section of an attachment  230  of the head  200  according to the second embodiment. 
       FIG.  10    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  in the head module  100  according to the embodiment. 
     The attachment  230  of the head  200  includes the through hole  231  to which the screw  400  is inserted. The through hole  231  includes the female screw  232 , into which the screw  400  can be screwed, the first concave  233  (hole part), which opens toward the holder  300  side with a diameter that is larger than the diameter a of the valley of the female screw  232 , and the second concave  234  (hole part), which opens toward a side opposite to the holder  300 . The second concave  234  has a diameter larger than a diameter a of the valley of the female screw  232 . 
     The second concave  234  of the present embodiment is a counterbored hole for accommodating the screw head  403  of the screw  400 . 
     With such a configuration, as illustrated in  FIG.  10   , the screw head  403  of the screw  400  is accommodated in the second concave  234  so as not to protrude from the attachment  230  when the head  200  is fixed and attached to the holder  300  with the screw  400 . 
     Next, the third embodiment of the present embodiment is described below with reference to  FIG.  11    and  FIG.  12   . 
       FIG.  11    is an explanatory diagram of the head module  100  according to the third embodiment along the longitudinal direction of the head. 
       FIG.  12    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  corresponding to the B part of  FIG.  11   . 
     In the present embodiment, the attachments  230  of the head  200  are fixed and attached on the lower surface side of the holder  300 . 
     Here, the through hole  231  of the attachment  230  of the head  200  is the same as in the first embodiment described above. 
     Next, the fourth embodiment of the present embodiment is described below with reference to  FIG.  13   . 
       FIG.  13    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  in the head module  100  according to the fourth embodiment. 
     In the present embodiment, the attachment  230  of the head  200  is fixed and attached to the lower surface side of the holder  300 . 
     Here, the through hole  231  of the attachment  230  of the head  200  is the same as in the second embodiment described above. 
     Next, the fifth embodiment of the present embodiment is described below with reference to  FIG.  14   . 
       FIG.  14    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  according to the fifth embodiment. 
     In the present embodiment, the through hole  231  of the attachment  230  of the head  200  includes the third concave  235  (hole part) having the same diameter (including the same and a larger diameter with a tolerance) as the diameter a of the valley of the female screw  232  between the female screw  232  and the first concave  233 . 
     In this way, even with the third concave  235  having the same diameter as the diameter a of the valley of the female screw  232 , since the diameter c of the shaft  401  of the screw  400  is smaller than the diameter a of the valley of the female screw  232 , the shaft  401  of the screw  400  can pass through the section of the third concave  235 . 
     Accordingly, when the male screw  402  of the screw  400  has passed through the female screw  232  of the through hole  231 , the inclination of the screw  400  can be reduced. 
     Next, the sixth embodiment of the present embodiment is described below with reference to  FIG.  15   . 
       FIG.  15    is an explanatory diagram for a cross section of a part of the attachment mechanism for the head  200  and the holder  300  according to the sixth embodiment. 
     In the present embodiment, the through hole  231  of the attachment  230  of the head  200  includes the fourth concave  236  (hole part) disposed opposite to the holder  300 . That is, the fourth concave  236  is disposed opposite to a side of the first concave  233  with the female screw  232  in between (disposed opposite side of the first concave  233  with respect to the female screw  232 ). 
     The fourth concave  236  has the same diameter (including the same and a larger diameter with a tolerance) as the diameter a of the valley of the female screw  232 . The fourth concave  236  faces the screw head  403  of the screw  400 . The female screw  232  is between the first concave  233  and the fourth concave  236 . 
     In this way, even with the fourth concave  236  having the same diameter as the diameter a of the valley of the female screw  232 , since the diameter c of the shaft  401  of the screw  400  is smaller than the diameter a of the valley of the female screw  232 , the shaft  401  of the screw  400  can pass through the section of the fourth concave  236 . 
     Accordingly, when the male screw  402  of the screw  400  is inserted to the through hole  231 , the male screw  402  can be guided by the fourth concave  236  to the female screw  232 , and thus the workability at the time of inserting the screw  400  to the through hole  231  of the attachment  230  is improved. 
     Next, the seventh embodiment of the present embodiment is described below with reference to  FIG.  16    and  FIG.  17 A  to  FIG.  17 C . 
       FIG.  16    is an explanatory diagram of an external perspective view of the head  200  according to the present embodiment. 
       FIG.  17 A  to  FIG.  17 C  are explanatory diagrams of the head  200 . 
     The head  200  of the present embodiment includes the two screw heads  210 , the base  201  on which the screw heads  210  are disposed in a staggered manner, and the cover  202  that covers the port member  218 , etc., for the base  201 . 
     Each screw head  210  of the base  201  includes the nozzle plate  212  in which the nozzles  211  are formed, an individual channel member (actuator substrate) including an individual channel plate formed with pressure chambers and the like leading to the nozzles  211  and a diaphragm plate integrally formed with piezoelectric elements, a common channel member formed as a common channel communicating with the multiple pressure chambers, etc. 
     Further, the base  201  includes the attachments  230  as flanges at both ends in the longitudinal direction, and the attachments  230  include the through holes  231  as described in each of the embodiments described above. 
     Next, the eighth embodiment of the present embodiment is described below with reference to  FIG.  18   . 
       FIG.  18    is a planar explanatory diagram of the head module according to the embodiment. 
     In the head module  100  of the present embodiment, the multiple heads  200  described in the above-described first embodiment are disposed in a staggered manner on the holder  300 . The attachments  230  of each head  200  can be include the through holes  231  described in each of the above embodiments. 
     In this way, when the multiple heads  200  are disposed side by side, since it is possible to hold the screws  400  in the through holes  231  of the heads  200  in advance, the heads  200  can be easily fixed and attached to the holder  300  with the screws  400  even in a small workspace. 
     Next, the ninth embodiment of the present embodiment is described below with reference to  FIG.  19   .  FIG.  19    is a planar explanatory diagram of the head module according to the embodiment. 
     In the head module  100  of the present embodiment, the multiple heads  200  described in the above-described seventh embodiment are disposed in a staggered manner on the holder  300 . The attachments  230  of each head  200  may include the through holes  231  described in each of the embodiments described above. 
     In the present embodiment, although the workspace is smaller than in the eighth embodiment described above, since it is possible to hold the screws  400  in the through holes  231  of the heads  200  in advance, the heads  200  can be easily fixed and attached to the holder  300  with the screws  400 . 
     Next, the tenth embodiment of the present embodiment is described below with reference to  FIG.  20    through  FIG.  23   .  FIG.  20    is an explanatory diagram for a cross section of the head module according to the embodiment along the lateral direction of the head,  FIG.  21    and  FIG.  22    are explanatory diagrams for exploded perspective views of the head module, and  FIG.  22    is an explanatory diagram for an exploded perspective view from the nozzle surface side of the head module. 
     The head module  100  includes the multiple heads  200 , which are liquid discharge heads that discharge liquid, the holder  300 , the nozzle cover member  103 , the heat-radiation member  104 , the manifold  105 , the printed circuit board  106  (PCB), and the module case  107 . 
     The heads  200  are circulation type heads, which include the nozzle plate  10  in which the nozzle  11  is formed, the individual channel plate  20  formed with the pressure chamber  21  leading to the nozzle  11 , etc., the diaphragm plate  30  including the piezoelectric element  40 , the intermediate channel plate  50  stacked on the diaphragm plate  30 , the common channel member  70  stacked on the intermediate channel plate  50 , etc. 
     Together with the pressure chamber  21 , the individual channel plate  20  forms the supply side individual channel  22  leading to the pressure chamber  21  and the collection side individual channel  24  leading to the pressure chamber  21 . 
     The intermediate channel plate  50  forms the supply side intermediate individual channel  51  leading to the supply side individual channel  22  via the opening  31  of the diaphragm plate  30  and the collection side intermediate individual channel  52  leading to the collection side individual channel  24  via the opening  32  of the diaphragm plate  30 . 
     The common channel member  70  forms the supply side common channel  71  leading to the supply side intermediate individual channel  51  and the collection side common channel  72  leading to the collection side intermediate individual channel  52 . The supply side common channel  71  leads to the supply port  81  via the channel  151  of the manifold  105 . The collection side common channel  72  leads to the collection port  82  via the channel  152  of the manifold  105 . 
     The printed circuit board  106  and the piezoelectric element  40  are connected via the flexible wiring member  90 , and the driver IC (drive circuit)  91  is mounted on the flexible wiring member  90 . The driver IC  91  is thermally coupled to the heat-radiation member  104 . 
     The head  200  is inserted to the opening  301  formed in the holder  300  and is fixed by joining the peripheral edge part of the individual channel plate  20  to the nozzle cover member  103 , which is joined and fixed to the holder  300 . 
     Further, the attachments  230  formed in the common channel member  70  are fixed to the holder  300  with the screws  400 . 
     Further, the holder  300  includes the attachments  330  at two positions, and the attachments  330  include the through holes  331 . 
     As with the through holes  231  of the head  200  described in each of the above-described embodiments, these through holes  331  are configured to have a female screw and the first concave, which opens toward the holder that holds this head module  100  and has a diameter larger than the diameter of the valley of the female screw. 
     Next, an example of the liquid discharge apparatus according to the present embodiment is described below with reference to  FIG.  24    and  FIG.  25   . 
       FIG.  24    is a schematic explanatory diagram of the apparatus, and  FIG.  25    is a planar explanatory diagram of an example of the discharge unit of the apparatus. 
     The printer  500 , which is an apparatus corresponding to the liquid discharge apparatus, includes the installation unit  501  that installs the continuous body  510 , the guide/conveyance unit  503  that guides and conveys the continuous body  510  to the printing unit  505 , such as continuous ledger paper or a continuous sheet installed by the installation unit  501 , the printing unit  505  that performs printing by discharging liquid to the continuous body  510  to form an image, the drying unit  507  that dries the continuous body  510 , the ejection unit  509  that ejects the continuous body  510 , etc. 
     The continuous body  510  is fed from the wound roller  511  of the installation unit  501 , guided and conveyed by the respective rollers of the installation unit  501 , the guide/conveyance unit  503 , the drying unit  507 , and the ejection unit  509 , and wounded by the winder roller  591  of the ejection unit  509 . 
     In the printing unit  505 , this continuous body  510  is conveyed in such a manner facing the discharge unit  550 , so that an image is printed with the liquid discharged from the discharge unit  550 . 
     As illustrated in  FIG.  24   , the discharge unit  550  includes the two head modules described in the above-described tenth embodiment, i.e., the head module  100 A and head module  100 B, in the holder  300  common to the head module  100 A and head module  100 B. 
     Here, the head modules  100  are fixed and attached to the holder  300  with the screws  400  through the through holes  331  formed in the head modules  100 . 
     Note that, with respect to the head arrangement direction, which is the direction in which the heads  200  are arranged in the head modules  100  and is the direction perpendicular to the conveyance direction, the head rows  200 A 1  and  200 A 2  of the head module  100 A discharge liquid of the same color. Similarly, the head rows  200 B 1  and  200 B 2  of the head module  100 A are paired, the head rows  200 C 1  and  200 C 2  of the head module  100 B are paired, and the head rows  200 D 1  and  200 D 2  are paired, so as to discharge liquid of the respective colors as desired. 
     Note that the head modules according to the present embodiment can be integrated with functional components and mechanisms, so as to configure the liquid discharge unit. For example, the head modules can be combined with at least one of a head tank, carriage, supply mechanism, maintenance/recovery mechanism, main-scanning movement mechanism, and configurations of a liquid circulation apparatus. 
     Here, the term “integrate” includes, for example, that a head module and functional components or mechanisms are fastened, joined, engaged, etc., so as to be fixed to each other or so that one is held with the other in a movable manner. Further, the head module and the functional components or mechanisms may be configured to be removable from each other. 
     Further, the “liquid discharge apparatus” in the present embodiment includes an apparatus including a head, head module, or liquid discharge units to discharge liquid by driving the liquid discharge head. 
     The liquid discharge apparatus includes, not only an apparatus that can discharge liquid to an object to which liquid can be attached, but also a liquid discharge apparatus into gas or liquid. 
     The “liquid discharge apparatus” can include a means relating to the feeding, conveying, and ejecting of an object to which liquid can be attached, and, moreover, a pre-processing apparatus, a post-processing apparatus, and the like. 
     For example, the “liquid discharge apparatus” may be an image forming apparatus, which is an apparatus that discharges ink to form an image on a sheet, or a stereoscopic modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto a powdery material layer, which is formed by layering powdery material, in order to produce a stereoscopic modeled object (three-dimensional modeled object). 
     Further, the “liquid discharge apparatus” is not limited to a liquid discharge apparatus for visualizing meaningful images such as letters and figures. For example, an apparatus that forms a pattern and the like that does not have meaning by itself and an apparatus that produces a three-dimensional model are included. 
     The above-mentioned “object to which liquid can be attached” is indicative of an object to which liquid can be attached at least temporarily, an object to which liquid can be attached and fixed, an object to which liquid can be attached and permeate, etc. Unless otherwise specified, anything that liquid can be attached to is included, and specific examples include media to be recorded such as sheets, record paper, record sheets, films, and cloths, electronic components such as electronic substrates and piezoelectric elements, and other media such as powdery material layers (powder layers), organ models, and cells for inspection. 
     The material of the aforementioned “object to which liquid can be attached” may be anything to which liquid can be attached at least temporarily, such as paper, yarn, fiber, fabric, leather, metals, plastics, glass, wood, and ceramics. 
     Further, although the “liquid discharge apparatus” is an apparatus in which the liquid discharge head moves relative to the object to which liquid can be attached, there is not a limitation as such. Specific examples include a serial type apparatus which moves the liquid discharge head, a line type apparatus which does not move the liquid discharge head, etc. 
     Further, in addition, the “liquid discharge apparatus” may be a processing liquid applying apparatus that discharges a processing liquid onto a sheet in order to apply the processing liquid onto the sheet surface for a purpose of improving the quality of the sheet surface, etc., a spray granulation apparatus that sprays a composition liquid having raw materials dispersed inside of the liquid through a nozzle to granulate fine particles of the raw material, etc. 
     Although the liquid to be discharged is not limited in particular and can be anything that has a viscosity and a surface tension suitable for being discharged from the head, it is preferable to use a liquid whose viscosity becomes 30 mPa·s or less by heating or cooling under a normal temperature and normal pressure. 
     More specifically, the liquid may be a solution, a suspension, an emulsion, or the like including a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalization material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acid, protein, or calcium, an edible material such as a natural colorant, etc., and, for example, these can be used for the purposes of an inkjet ink, a surface treatment solution, a liquid for forming a constituent element of an electronic element or a light-emitting element or a resist pattern of an electronic circuit, or a material solution for three-dimensional modeling. 
     The energy generating source for discharging liquid includes ones using a piezoelectric actuator (laminated type piezoelectric element or thin film type piezoelectric element), a thermal actuator which uses an electricity-heat conversion element such as a heating resistor, an electrostatic actuator configured with a diaphragm plate and counter electrodes, etc. 
     Note that, among the terms of the present application, terms such as image forming, recording, letter printing, photo printing, printing, and modeling are synonyms. 
     Further, although the head or head module is described as the first member and the holder is described as the second member in the above-described embodiments, the present embodiment is not limited to the head and the head module and can be universally applied to a module or an apparatus in which the first member and the second member are fixed and attached with a screw. 
     Aspect 1 
     A head ( 200 ) includes: an attachment ( 230 ) attached to a holder ( 300 ) with a screw ( 400 ), the attachment ( 230 ) having a through hole ( 231 ) to which the screw ( 400 ) is inserted, and the through hole ( 231 ) having: a female screw ( 232 ) having a valley and a crest; and a first concave ( 233 ) having a diameter larger than a diameter of the valley of the female screw ( 232 ), the first concave ( 233 ) opening toward the holder ( 300 ). 
     Aspect 2 
     In the head ( 200 ) according to Aspect 1, the through hole ( 231 ) includes a second concave ( 234 ) having a diameter larger than the diameter of the valley of the female screw ( 232 ), and the second concave opening toward a side opposite to the holder ( 300 ). 
     Aspect 3 
     In the head ( 200 ) according to Aspect 1, the head ( 200 ) discharges a liquid. 
     Aspect 4 
     A head module ( 100 ) includes: a holder ( 300 ); a head ( 200 ) attached to the holder ( 300 ); and a screw ( 400 ) fixing the head to the holder ( 300 ). The head ( 200 ) includes: an attachment ( 230 ) having a through hole ( 231 ) to which the screw ( 400 ) is inserted, the through hole ( 231 ) includes: a female screw ( 232 ) having a valley and a crest; and a first concave ( 233 ) having a diameter larger than a diameter of the valley of the female screw ( 232 ), the first concave ( 233 ) opening toward the holder ( 300 ), and the screw ( 400 ) includes: a screw head ( 403 ); a male screw ( 402 ) at a tip of the screw ( 400 ); and a shaft ( 401 ) between the screw head ( 403 ) and the male screw ( 402 ) and narrower than a diameter of the crest of the female screw ( 232 ). 
     Aspect 5 
     In the head module ( 100 ) according to Aspect 4, the through hole ( 231 ) includes a second concave ( 234 ) having a diameter larger than the diameter of the valley of the female screw ( 232 ), and the second concave opening toward a side opposite to the holder ( 300 ). 
     Aspect 6 
     In the head module ( 100 ) according to Aspect 4, a depth (d) of the first concave ( 233 ) is deeper than a length (e) of the male screw ( 402 ) of the screw ( 400 ). 
     Aspect 7 
     In the head module ( 100 ) according to Aspect 4, the holder ( 300 ) has a female screw ( 302 ), and a shape and a size of the female screw ( 302 ) is identical to a shape and a size of the female screw ( 232 ) of the head ( 200 ). 
     Aspect 8 
     In the head module ( 100 ) according to Aspect 4, the head ( 200 ) discharges a liquid. 
     Aspect 9 
     A liquid discharge apparatus ( 500 ) includes the head ( 200 ) according to Aspect 3. 
     Aspect 10 
     A liquid discharge apparatus ( 500 ) includes the head module ( 100 ) according to Aspect 8. 
     Aspect 11 
     A printer ( 500 ) includes the head ( 200 ) according to Aspect 1. 
     Aspect 12 
     A printer ( 500 ) includes the head module according to Aspect 4. 
     Aspect 13 
     A module ( 100 ) includes: a first member ( 200 ); a second member ( 300 ); and a screw ( 400 ) fixing the first member ( 200 ) to the second member ( 300 ). The first member ( 200 ) includes: an attachment ( 230 ) having a through hole ( 231 ) to which the screw ( 400 ) is inserted, the through hole ( 231 ) includes: a female screw ( 232 ) having a valley and a crest; and a first concave ( 233 ) having a diameter larger than a diameter of the valley of the female screw ( 232 ), the first concave ( 233 ) opening toward the second member ( 300 ), and the screw ( 400 ) includes: a screw head ( 403 ); a male screw ( 402 ) at a tip of the screw ( 400 ); and a shaft ( 401 ) between the screw head ( 403 ) and the male screw ( 402 ) and narrower than a diameter of the crest of the female screw ( 232 ). 
     Aspect 14 
     An apparatus ( 500 ) includes the module according to Aspect 13. 
     Aspect 15 
     In the head ( 200 ) according to Aspect 1, the through hole ( 231 ) includes a third concave ( 235 ) between the female screw ( 232 ) and the first concave ( 233 ), and the third concave ( 235 ) has a diameter same as the diameter of the valley of the female screw ( 232 ). 
     Aspect 16 
     In the head ( 200 ) according to Aspect 1, the through hole ( 231 ) includes a fourth concave ( 236 ) disposed opposite to a side of the first concave ( 233 ) with the female screw ( 232 ) in between, and the fourth concave ( 236 ) has a diameter same as the diameter of the valley of the female screw ( 232 ). 
     According to the present embodiment, the workability of the attachment work with a screw is improved. 
     The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention.