Patent Publication Number: US-2023135522-A1

Title: Liquid discharge head, discharge unit, and liquid discharging 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. 2021-176600, filed on Oct. 28, 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 liquid discharge head, a discharge unit, and a liquid discharging apparatus. 
     Related Art 
     A liquid discharge head discharges a liquid. The liquid discharge head includes a nozzle plate having multiple nozzles from which a liquid is to be discharged, an individual channel member including multiple pressure chambers respectively communicating with the nozzles, and a common channel member including a common channel communicating with the pressure chambers. 
     The liquid discharge head includes a channel forming substrate and a bonding substrate made of a material different from the material of the channel forming substrate. The bonding substrate is bonded to the channel forming substrate. The channel forming substrate has a low rigidity part lower in rigidity than other parts in an outer peripheral portion on one side of the channel forming substrate. 
     A method for manufacturing the liquid discharge head includes a process for integrally forming multiple channel forming substrates on a silicon wafer and providing multiple through holes aligned at specified intervals between the channel forming substrates on the silicon wafer to form a break pattern, a process for bonding a bonding substrate to a channel forming substrate, and a process for dividing the silicon wafer along the break pattern into the channel forming substrates. During the formation of the break pattern, through holes are successively formed in portions of the silicon wafer that correspond to the low rigidity parts. 
     SUMMARY 
     A liquid discharge head includes: a nozzle plate having multiple nozzles from each of which a liquid is to be discharged; a first substrate including multiple pressure chambers respectively communicating with the multiple nozzles; and a second substrate including: a common channel communicating with the multiple pressure chambers, the common channel extending in a longitudinal direction of the second substrate; and a reinforcement in the common channel, the reinforcement intersecting the longitudinal direction. 
     A liquid discharge head includes: a nozzle plate having multiple nozzles from each of which a liquid is to be discharged; a first substrate including multiple pressure chambers respectively communicating with the multiple nozzles; and a second substrate including a hole region having multiple holes, the multiple holes defining a common channel communicating with each of the multiple pressure chambers. 
     A discharge unit includes the liquid discharge head, and the liquid discharge head includes multiple liquid discharge heads. 
     A liquid discharging apparatus includes the liquid discharge head. 
     A liquid discharging apparatus includes the discharge unit. 
    
    
     
       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 a perspective view illustrating an appearance of a liquid discharge head according to a first embodiment of this disclosure; 
         FIG.  2    is a cross-sectional view of the liquid discharge head in  FIG.  1   ; 
         FIGS.  3 A and  3 B  are plan views of a second substrate; 
         FIGS.  4 A and  4 B  are diagrams for explaining a state where the second substrate and a damper member are bonded to each other; 
         FIG.  5    is a plan view of a first substrate; 
         FIG.  6    is a perspective view for explaining a state where the first substrate and the second substrate are bonded to each other; 
         FIG.  7    is a perspective view for explaining a state where the second substrate is bonded to a dicing tape; 
         FIG.  8    is a plan view for explaining expansion; 
         FIGS.  9 A and  9 B  are plan views of the second substrate in the first embodiment, for explaining effects of a reinforcement provided; 
         FIGS.  10   a    and  10 B are plan views of a second substrate in Comparative Example 1; 
         FIG.  11    is a perspective view illustrating a second substrate in a liquid discharge head according to a second embodiment of this disclosure, along with a dicing tape; 
         FIG.  12    is a plan view of a second substrate in a liquid discharge head according to a third embodiment of this disclosure; 
         FIG.  13    is a perspective view illustrating an appearance of a liquid discharge head according to a fourth embodiment of this disclosure; 
         FIG.  14    is a perspective view illustrating an appearance of the liquid discharge head in  FIG.  13    as viewed from a side opposite with a nozzle face side; 
         FIG.  15    is an exploded perspective view of the liquid discharge head in  FIG.  13   ; 
         FIG.  16    is an exploded perspective view of channel constituent members in the liquid discharge head in  FIG.  13   ; 
         FIG.  17    is an enlarged perspective view of a principal part of the channel constituent members in  FIG.  16   ; 
         FIG.  18    is a perspective view of a cross section of a channel part in the liquid discharge head in  FIG.  13   ; 
         FIG.  19    is a schematic side view of an example of a printing apparatus as a liquid discharging apparatus according to this disclosure; and 
         FIG.  20    is a plan view of a discharge unit of the printing apparatus in  FIG.  19   . 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. 
     In the following, embodiments of this disclosure are described with reference to the accompanying drawings. A first embodiment of this disclosure is described with reference to  FIGS.  1  through  7   .  FIG.  1    is a perspective view illustrating an appearance of a liquid discharge head according to the first embodiment, and  FIG.  2    is a cross-sectional view of the liquid discharge head in  FIG.  1   . 
       FIGS.  3 A and  3 B  are plan views of a second substrate. 
       FIGS.  4 A and  4 B  are diagrams for explaining a state in which the second substrate and a damper member are bonded to each other. 
       FIG.  4 A  is a plan view, and  FIG.  4 B  is a cross-sectional view along a line A-A in  FIG.  4 A . 
       FIG.  5    is a plan view of a first substrate. 
       FIG.  6    is a perspective view for explaining a state where the first substrate and the second substrate are bonded to each other. 
       FIG.  7    is a perspective view for explaining a state where the second substrate is bonded to a dicing tape. The damper member is omitted from  FIG.  6   . 
     A liquid discharge head  100  includes a nozzle plate  110 , a first substrate  190 , a second substrate  170 , a damper member  160 , a frame member  180 , and a wiring member  145  (flexible circuit substrate). 
     The nozzle plate  110  has multiple nozzles  111  from which a liquid is to be discharged. The nozzles  111  are two-dimensionally arranged in a matrix. 
     The first substrate  190  forms multiple pressure chambers  121  (individual chambers or individual channels) communicating with the nozzles  111 , respectively, and multiple common supply channel branches  152  as common channel branches each communicating with two or more pressure chambers  121 . On the first substrate  190 , piezoelectric elements  140  to pressurize the pressure chambers  121  are arranged. 
     The first substrate  190  also forms a part  156 a of a common supply main channel  156  that is one or more in number and communicates with the common supply channel branches  152 . 
     The second substrate  170  is a common main channel member and forms the common supply main channel  156  as a common channel communicating with the common supply channel branches  152 . In the present embodiment, the common supply main channel  156  serving as a common channel is arranged on both sides in a transverse direction of the second substrate  170 . 
     In the frame member  180 , a supply port  181  and a supply path  183  that communicates with the supply port  181  and the common supply main channel  156  are formed. 
     In the liquid discharge head  100 , multiple reinforcements  171  extending in a direction intersecting a longitudinal direction of the common supply main channel  156  are provided in a region of the second substrate  170  that forms the common supply main channel  156 , as illustrated in  FIGS.  3 ,  6 , and  7   . 
     In the present embodiment, the reinforcements  171  have a thickness t 2  equal to a thickness t 1  of the second substrate  170 . Consequently, the common supply main channel  156  is divided by the reinforcements  171  into multiple (three in the illustrated example) openings (channel parts)  156 A in the longitudinal direction of the common supply main channel  156 . 
     As a result, the second substrate  170  in the form of a thin layer has a high rigidity as compared with the case where one long opening is formed as a common channel (the common supply main channel  156  in the present embodiment). 
     A high rigidity of the second substrate  170  reduces the damage due to the expansion (division) during the manufacture of the liquid discharge head  100 . 
     The damper member  160  is bonded on a bonding side of the second substrate  170  to be bonded to the first substrate  190 . On the bonding side of the second substrate  170  to be bonded to the first substrate  190 , a recess  178  serving as a damper chamber is formed. 
     The damper member  160  forms deformable walls of the common supply channel branches  152 . The damper member  160  doubles as a filter member, and a region corresponding to the common supply main channel  156  of the second substrate  170  is made to be a filter region  163  where many (multiple) filter holes  164  are formed, as illustrated in  FIG.  4 A . 
     Next, the expansion is explained further referring to  FIG.  8   .  FIG.  8    is a plan view for explaining the expansion. 
     On a silicon wafer  914 , many second substrates  170   a  are formed that are each used as the second substrate  170  after the division of the silicon wafer  914 . A dicer or the like is used to make cracks in the silicon wafer  914 , on which the second substrates  170   a  have been formed, as division lines  913 . 
     Then, a dicing tape  915  that the silicon wafer  914  has been adhered to is pulled in 360-degree directions as illustrated with arrows in the figure, so as to divide the silicon wafer  914  along the division lines  913  into individual second substrates  170  each in a chip form. 
     During the division, the second substrate  170  may be deformed in accordance with the stretch of the dicing tape  915  if the second substrate  170  has a pattern with a low rigidity. 
     The reinforcements  171  provided in an opening forms the common supply main channel  156  of the second substrate  170 . The reinforcements  171  suppress the deformation of the second substrate  170  during the expansion. Thus, the reinforcements  171  can prevent the damage of a chip of the second substrate  170 , generation of silicon flakes by rubbing of chips, and the like. 
     Effects of reinforcements are explained with reference to  FIGS.  9 A,  9 B,  10 A, and  10 B . 
       FIGS.  9 A and  9 B  are plan views of the second substrate in the first embodiment, and  FIGS.  10 A and  10 B  are plan views of a second substrate in Comparative Example 1.  FIGS.  9 A and  10 B  are each to illustrate the state of the second substrate before the expansion, and  FIGS.  9 B and  10 B  are each to illustrate the state of the second substrate after the expansion. 
     As also illustrated in  FIGS.  9 A and  9 B , the second substrate  170   a  in the first embodiment includes the reinforcements  171  provided in the common supply main channel  156 . The second substrate  170   a  in Comparative Example 1 forms a common supply main channel  156  that consists of one elongated opening, as illustrated in  FIGS.  10 A and  10 B . 
     A wafer that the second substrates  170   a  in the first embodiment have been formed on and a wafer that the second substrates  170   a  in Comparative Example 1 have been formed on were prepared so as to check whether deformation actually occurs during the expansion, and whether the damage of a part and the generation of foreign bodies are observed. On both of the second substrates  170   a  in the first embodiment and the second substrates  170   a  in Comparative Example 1, a silicon membrane serving as the damper member  160  was formed. 
     In Comparative Example 1, five wafers were prepared and expanded and, as a result, the deformation of a chip of a second substrate  170 b after the expansion as illustrated in  FIG.  10 B  was observed on every chip of every wafer. The second substrate  170   b  with the maximum deformation exhibited deformation of about 350 μm in the transverse direction. 
     With respect to the damper member  160  formed on the second substrates  170   a , the damage of the membrane was recognized on about 60% of the chips. When five chips were extracted to check on foreign bodies, it was found that a maximum of about 50 foreign bodies with a size of 10 μm or more were adhered to one chip. 
     In contrast, for the first embodiment, five wafers were prepared and expanded and, as a result, significant deformation of a chip of a second substrate  170   b  after the expansion was not observed on any chip of any wafer, as seen from  FIG.  9 B . The second substrate  170   b  with the maximum deformation exhibited deformation of about 10 μm in the transverse direction, namely, deformation greatly reduced from the maximum deformation in Comparative Example 1. 
     With respect to the damper member  160  formed on the second substrates  170   a , any damage of the membrane was not recognized. When five chips were extracted to check on foreign bodies, no foreign bodies with a size of  10 μm or more were recognized. 
     Next, a second embodiment of this disclosure is described with reference to  FIG.  11   .  FIG.  11    is a perspective view illustrating a second substrate in a liquid discharge head according to the second embodiment, along with a dicing tape. 
     Also in the present embodiment, multiple reinforcements  171  extending in a direction intersecting a longitudinal direction of a common supply main channel  156  are provided in a region of a second substrate  170  that forms the common supply main channel  156 . 
     On the other hand, in the present embodiment, the reinforcements  171  have a thickness t 2  smaller than a thickness t 1  of the second substrate  170  (t 2 &lt;t 1 ). In addition, the reinforcements  171  are so provided as to be closer to a bonding side of the second substrate  170  to be bonded to the first substrate  190 . 
     Consequently, a channel extending in the longitudinal direction is maintained in the common supply main channel  156  and the volume of the common supply main channel  156  is ensured. In other words, since the reinforcements  171  with a larger volume offer a higher fluid resistance, the reinforcements  171  are reduced in volume as much as possible so as to lower the fluid resistance due to the reinforcements  171  as provided. 
     The reinforcements  171 , which are so provided as to be closer to the bonding side of the second substrate  170  to be bonded to the first substrate  190 , are in contact with the dicing tape  915  during the expansion, which is adequately effective at preventing the deformation. 
     With respect to the present embodiment, similarly to the first embodiment, a wafer was prepared to check the second substrate  170  during the expansion on deformation, damage, and foreign bodies. As a result, it was found that the deformation of the second substrate  170  was of an amount of at most about 10 μm, the membrane of the damper member  160  was not damaged, and no foreign bodies with a size of 10 μm or more were present. 
     Next, a third embodiment of this disclosure is described with reference to  FIG.  12   .  FIG.  12    is a plan view of a second substrate  170  in a liquid discharge head according to the third embodiment, with a left part illustrating the second substrate  170  as a whole and a right part illustrating part of the second substrate  170  in an enlarged manner. 
     In the present embodiment, many (multiple) holes  174  are provided in a hole region  173  of a second substrate  170  that forms a common main channel, so as to form a common supply main channel  156  with the holes  174 . A region other than the hole region  173  of the second substrate  170  is referred to as a “non-hole region  175 ” (see  FIG.  12   ). 
     Such configuration increases the rigidity of the second substrate  170 . 
     The holes  174  can be made equal in opening area to the filter holes  164  in the filter region  163  of the damper member  160  in the first embodiment. 
     In that case, the second substrate  170  is caused to double as a filter member and the filter region  163  of the damper member  160  in the first embodiment is made to be a simple opening. 
     With respect to the present embodiment, similarly to the first embodiment, a wafer was prepared to check the second substrate  170  during the expansion on deformation, damage, and foreign bodies. The holes  174  were each given a hole diameter of 24 μm that is equal to the hole diameter of the filter holes  164  in the filter region  163  of the damper member  160  in the first embodiment. The filter region  163  of the damper member  160  was made to be a simple opening. 
     As a result, it was found that the deformation of the second substrate  170  was of a measurement error-level amount of about 1.2 μm, the membrane of the damper member  160 , whose filter region  163  was a simple opening, was not damaged, and no foreign bodies with a size of 10 μm or more were present. 
     Next, a fourth embodiment of this disclosure is described with reference to  FIGS.  13  through  18   .  FIG.  13    is a perspective view illustrating an appearance of a liquid discharge head according to the fourth embodiment as viewed from a nozzle face side,  FIG.  14    is a perspective view illustrating an appearance of the liquid discharge head in  FIG.  13    as viewed from a side opposite with the nozzle face side, and  FIG.  15    is an exploded perspective view of the liquid discharge head in  FIG.  13   .  FIG.  16    is an exploded perspective view of channel constituent members in the liquid discharge head in  FIG.  13   ,  FIG.  17    is an enlarged perspective view of a principal part of the channel forming components in  FIG.  16   , and  FIG.  18    is a perspective view of a cross section of a channel part in the liquid discharge head in  FIG.  13   . 
     A liquid discharge head  100  of the present embodiment is a circulation type liquid discharge head and includes the nozzle plate  110 , a channel plate (individual channel member)  120 , a diaphragm member  130  including the piezoelectric elements  140 , a common channel branch member  150 , the damper member  160 , the second substrate  170  as a common main channel member, the frame member  180 , and the wiring member  145  (flexible circuit substrate). On the wiring member  145 , a head driver  146  (driver integrated circuit (IC)) is mounted. 
     In the present embodiment, the channel plate  120  and the diaphragm member  130  form an actuator substrate  102  that the piezoelectric elements  140  are arranged on. The channel plate  120  and the common channel branch member  150  correspond to the first substrate  190  in the first embodiment. 
     The nozzle plate  110  has the nozzles  111  from which a liquid is to be discharged. The nozzles  11   1  are two-dimensionally arranged in a matrix. 
     The channel plate  120  forms the pressure chambers  121  (individual chambers) communicating with the nozzles  111 , respectively, multiple individual supply channels  122  communicating with the pressure chambers  121 , respectively, and multiple individual collection channels  123  communicating with the pressure chambers  121 , respectively. 
     The diaphragm member  130  forms diaphragms  131  as deformable walls of the pressure chambers  121 , and the piezoelectric elements  140  are integrally provided on the diaphragms  131 . In the diaphragm member  130 , supply-side openings  132  communicating with the individual supply channels  122  and collection-side openings  133  communicating with the individual collection channels  123  are formed. The piezoelectric elements  140  are pressure generating means (pressure generating elements) for deforming the diaphragms  131  so as to pressurize liquid in the pressure chambers  121 . 
     The common channel branch member  150  forms multiple common supply channel branches  152  each communicating with two or more individual supply channels  122  and multiple common collection channel branches  153  each communicating with two or more individual collection channels  123  so that the common supply channel branches  152  and the common collection channel branches  153  may alternately be arranged. 
     In the common channel branch member  150 , through holes serving as supply ports  154  leading from the supply-side openings  132  of the individual supply channels  122  to the common supply channel branches  152  and through holes serving as collection ports  155  leading from the collection-side openings  133  of the individual collection channels  123  to the common collection channel branches  153  are formed. 
     In addition, the common channel branch member  150  forms a part  156 a of a common supply main channel  156  that is one or more in number and communicates with the common supply channel branches  152 , and a part  157 a of a common collection main channel  157  that is one or more in number and communicates with the common collection channel branches  153 . 
     The damper member  160  includes supply-side dampers facing (opposite to) the supply ports  154  of the common supply channel branches  152  and collection-side dampers facing (opposite to) the collection ports  155  of the common collection channel branches  153 . The filter region  163  described in the first embodiment can be provided on the damper member  160  as above. 
     With respect to the common supply channel branches  152  and the common collection channel branches  153 , grooves alternately arranged on the same common channel branch member  150  are sealed with the damper member  160 , which forms deformable walls, so as to form the common supply channel branches  152  and the common collection channel branches  153 . 
     The second substrate  170  is a common main channel member, and forms the common supply main channel  156  as a common channel communicating with the common supply channel branches  152  and the common collection main channel  157  as a common channel communicating with the common collection channel branches  153 . 
     On the frame member  180 , a part  156   b  of the common supply main channel  156  and a part  157   b  of the common collection main channel  157  are formed. 
     The part  156   b  of the common supply main channel  156  communicates with the supply port  181  provided on the frame member  180 , and the part  157   b  of the common collection main channel  157  communicates with a collection port  182  provided on the frame member  180 . 
     In the liquid discharge head  100  of the present embodiment, driving pulses are applied to the piezoelectric elements  140  so as to subject the piezoelectric elements  140  to flexural deformation, and the liquid in the pressure chambers  121  as pressurized by the deformed piezoelectric elements  140  is discharged dropwise through the nozzles  111 . 
     If the discharge of liquid from the liquid discharge head  100  is not performed or liquid has not been discharged through the nozzles  111 , the liquid circulates via a circulation path that the collection port  182  and the supply port  181  are connected to. 
     Also in the present embodiment, the second substrate  170  includes reinforcements  171  provided in parts forming the common supply main channel  156  and the common collection main channel  157 . The reinforcements  171  can have either of the thickness in the first embodiment and the thickness in the second embodiment. The common supply main channel  156  and the common collection main channel  157  may have the configuration of the common supply main channel  156  in the third embodiment. 
     In that case, the rigidity of the second substrate  170  is also increased in the present embodiment. 
     Next, an example of a printing apparatus as a liquid discharging apparatus according to this disclosure is described with reference to  FIGS.  19  and  20   .  FIG.  19    is a schematic side view of an exemplary printing apparatus, and  FIG.  20    is a plan view of a discharge unit of the printing apparatus in  FIG.  19   . 
     A printing apparatus  1  is a liquid discharging apparatus and includes a sending-in section  10  for sending in a cut sheet P, a pretreatment section  20 , a printing section  30 , a drying section  40 , a reversion mechanism section  60 , and a sending-out section  50 . 
     In the printing apparatus  1 , the pretreatment section  20  as a pretreatment means gives (applies), as desired, a pretreatment liquid to the cut sheet P sent in (fed) from the sending-in section  10 , the printing section  30  gives liquid to the cut sheet P so as to perform a desired printing, and the drying section  40  dries the liquid adhered to the cut sheet P and then ejects the cut sheet P to the sending-out section  50 . 
     The sending-in section  10  includes sending-in trays  11  (a lower sending-in tray  11 A and an upper sending-in tray  11 B) each containing multiple cut sheets P and feeding devices  12  ( 12 A and  12 B) for delivering the cut sheets P one by one from the sending-in trays  11 , and is to feed the cut sheets P to the pretreatment section  20 . 
     The pretreatment section  20  includes an applicator  21  as a treatment liquid giving means that gives a printing face of the cut sheet P a treatment liquid having an effect of condensing ink so as to prevent offset, for instance. 
     The printing section  30  includes a drum  31  as a carrying member (rotating member) that carries the cut sheet P on a peripheral face and as such rotates, and a liquid discharger  32  for discharging liquid toward the cut sheet P carried by the drum  31 . 
     The printing section  30  also includes a transfer barrel  34  that receives the cut sheet P sent from the pretreatment section  20 , so as to transfer the cut sheet P to the drum  31 , and a transfer barrel  35  that receives the cut sheet P conveyed by the drum  31 , so as to transfer the cut sheet P to the drying section  40 . 
     The cut sheet P conveyed from the pretreatment section  20  to the printing section  30  is grasped by a leading edge by a grasping means (sheet gripper) provided on the transfer barrel  34 , and conveyed in accordance with the rotation of the transfer barrel  34 . The cut sheet P conveyed by the transfer barrel  34  is transferred to the drum  31  in a position opposite to the drum  31 . 
     On a surface of the drum  31 , another grasping means (sheet gripper) is provided that is to grasp the cut sheet P by the leading edge. Multiple suction holes are so formed in the surface of the drum  31  as to be distributed, and a suction means is used to generate a suction air flow directed from a desired suction hole of the drum  31  inward. 
     The cut sheet P transferred from the transfer barrel  34  to the drum  31  is grasped by the leading edge by the sheet gripper and, at the same time, attracted onto and carried on the drum  31  by means of the suction air flow generated by the suction means, and as such  5  conveyed in accordance with the rotation of the drum  31 . 
     The liquid discharger  32  includes discharge units  33  ( 33 A through  33 D) as liquid discharging means. For instance, a discharge unit  33 A discharges a cyan (C) liquid, a discharge unit  33 B discharges a magenta (M) liquid, a discharge unit  33 C discharges a yellow (Y) liquid, and a discharge unit  33 D discharges a black (K) liquid. Another discharge unit for discharging a special liquid, such as a white liquid and a gold (silver) liquid, may also be used. 
     The discharge units  33  are each a full-line head where multiple liquid discharge heads  100  according to this disclosure, each including the nozzles  111  as two-dimensionally arrayed in a matrix, are staggered on a base  331  as illustrated in  FIG.  20   , for instance. 
     The discharge units  33  of the liquid discharger  32  are each controlled with respect to a discharging operation, based on a driving signal according to printing information. When the cut sheet P carried by the drum  31  passes through a region opposite to the liquid discharger  32 , liquids of different colors are discharged from the discharge units  33  so as to print an image according to the printing information. 
     The cut sheet P, which has been given the liquids by the liquid discharger  32 , is transferred from the drum  31  to the transfer barrel  35  and then transferred by the transfer barrel  35  to a conveyance mechanism  41  that sends the cut sheet P to the drying section  40 . 
     In the drying section  40 , the cut sheet P conveyed by the conveyance mechanism  41  is heated by a heating means  42  so as to dry the liquids adhered to the cut sheet P. As a result, liquid ingredients such as water in the liquids evaporate, colorants contained in the liquids are fixed onto the cut sheet P, and the curl of the cut sheet P is suppressed. 
     The reversion mechanism section  60  includes a mechanism for reversing the cut sheet P on a switchback basis if duplex printing is to be performed on the cut sheet P having passed through the drying section  40 . The cut sheet P as reversed is sent back upstream from the transfer barrel  34  via a two-way conveyance path  61 . 
     The sending-out section  50  includes a sending-out tray  51  where multiple cut sheets P are loaded. The cut sheets P conveyed from the drying section  40  via the reversion mechanism section  60  are sequentially stacked on the sending-out tray  51  and as such held. 
     In the present embodiment, 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 mPas under ordinary temperature and ordinary pressure or by heating or cooling. More specifically, examples thereof include solutions, suspensions, and emulsions containing solvents such as water and organic solvents, colorants such as dyes and pigments, function-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, edible materials such as natural pigments, and the like. 
     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 unit(s) 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. Further, the head, the functional parts, and the mechanism may be configured to be detachable from 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. A unit including a filter may be added at a position between the head tank  441  and the head  404  of the liquid discharge device. 
     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 a part of the 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 still another example, the liquid discharge device includes tubes connected to the head tank or the head mounting a channel member so that the head and the supply unit form a single unit. 
     A liquid in a liquid reservoir source such as an ink cartridge is supplied to the head through this 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. 
     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, the head device, and the liquid discharge device to discharge liquid by driving the head. 
     The liquid discharge apparatus may be, for example, an apparatus capable of discharging a 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 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 “material on which liquid can be adhered” includes any material on which liquid is adhered, unless particularly limited. 
     The above-mentioned “material onto which liquid can be adhered” may be any material as long as liquid can temporarily adhere such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or the like. 
     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, with the treatment liquid, a sheet surface to reform the sheet surface and an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is discharged 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. 
     According to this embodiment, the rigidity of the common flow path member can be increased. 
     [Aspect 1] 
     A liquid discharge head ( 100 ) includes: a nozzle plate ( 110 ) having multiple nozzles ( 111 ) from each of which a liquid is to be discharged; a first substrate ( 190 ) including multiple pressure chambers ( 121 ) respectively communicating with the multiple nozzles ( 111 ); and a second substrate ( 170 ) including: a common channel ( 156 ) communicating with the multiple pressure chambers ( 121 ), the common channel ( 156 ) extending in a longitudinal direction of the second substrate ( 170 ); and a reinforcement ( 171 ) in the common channel ( 156 ), the reinforcement ( 171 ) intersecting the longitudinal direction. 
     [Aspect 2] 
     In the liquid discharge head ( 100 ) according to Aspect 1, the reinforcement ( 171 ) has a thickness smaller than a thickness of the second substrate ( 170 ). 
     [Aspect 3] 
     In the liquid discharge head ( 100 ) according to Aspect 2, the reinforcement ( 171 ) is closer to one side in a thickness direction of the second substrate ( 170 ). 
     [Aspect 4] 
     In the liquid discharge head ( 100 ) according to Aspect 3, the first substrate ( 190 ) and the second substrate ( 170 ) are bonded with each other at a bonding surface, and the reinforcement ( 171 ) of the second substrate ( 170 ) is closer to the bonding surface in the thickness direction. 
     [Aspect 5] 
     A liquid discharge head ( 100 ) includes: a nozzle plate ( 110 ) having multiple nozzles ( 111 ) from each of which a liquid is to be discharged; a first substrate ( 190 ) including multiple pressure chambers ( 121 ) respectively communicating with the multiple nozzles ( 111 ); and a second substrate ( 170 ) including a hole region ( 173 ) having multiple holes ( 174 ), the multiple holes ( 174 ) defining a common channel ( 156 ) communicating with each of the multiple pressure chambers ( 121 ). 
     [Aspect 6] 
     In the liquid discharge head ( 100 ) according to Aspect 5, wherein the hole region ( 173 ) has a thickness smaller than a thickness of a non-hole region ( 175 ) other than the hole region ( 173 ) of the second substrate ( 170 ). 
     [Aspect 7] 
     In the liquid discharge head according to Aspect 6, the hole region ( 173 ) is closer to one side in a thickness direction of the second substrate ( 170 ). 
     [Aspect 8] 
     In the liquid discharge head according to Aspect 7, the first substrate ( 190 ) and the second substrate ( 170 ) are bonded with each other at a bonding surface, and the hole region ( 173 ) of the second substrate ( 170 ) is closer to the bonding surface in the thickness direction. 
     [Aspect 9] 
     In the liquid discharge head according to Aspect 8, the multiple holes ( 174 ) of the hole region ( 173 ) is a filter configured to filtering the liquid passing through the multiple holes ( 174 ) from the common channel ( 156 ) of the second substrate ( 170 ) to the multiple pressure chambers ( 121 ) of the first substrate ( 190 ). 
     [Aspect 10] 
     In a discharge unit ( 33 ) includes the liquid discharge head according to Aspect 1, the liquid discharge head ( 100 ) includes multiple liquid discharge heads ( 100 ). 
     [Aspect 11] 
     A liquid discharging apparatus ( 1 ) comprising the liquid discharge head ( 100 ) according to Aspect 1. 
     [Aspect 12] 
     A liquid discharging apparatus ( 1 ) comprising the discharge unit ( 33 ) according to Aspect 10. 
     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.