Liquid discharge head, liquid discharge apparatus, and liquid filling method

Abstract

A liquid discharge head includes: a nozzle forming wall having multiple nozzles from each of which a liquid is dischargeable in a discharge direction; multiple individual channels respectively having: multiple first faces each formed by the nozzle forming wall and respectively communicating with the multiple nozzles; and multiple second faces respectively opposite to the multiple first faces in the discharge direction, the multiple second faces respectively having multiple openings; multiple actuators driven to discharge the liquid in the multiple individual channels from the multiple nozzles, respectively; a first common channel including first multiple common-branch channels partitioned from each other by a first partition wall; and a second common channel including second multiple common-branch channels partitioned from each other by a second partition wall.

Description

[DESCRIPTION][Title of Invention]LIQUID DISCHARGE HEAD, LIQUID DISCHARGE APPARATUS, AND LIQUID FILLING METHOD [Technical Field]

[0001] The present embodiment relates to a liquid discharge head, a liquid discharge apparatus, and a liquid filling method.

[0002] Conventionally, there has been known a liquid discharge head including multiple nozzles for discharging liquid, multiple individual channels respectively communicating with the multiple nozzles, multiple actuators respectively provided for the multiple individual channels, and a common channel facing openings of the multiple individual channels located on a side facing a nozzle forming wall, wherein the actuators are driven to discharge liquid in the individual channels from the nozzles.

[0003] For example, Patent Literature (PTL) 1 discloses a liquid discharge head including a nozzle plate (nozzle forming wall) on which multiple nozzles and multiple actuators are formed, a substrate on which multiple cylindrical pressure chambers communicating respectively with the multiple nozzles is formed, and a damper member. Each of the actuators is formed in an annular shape coaxial with each of the nozzles, and is driven to pressurize the liquid in each pressure chamber. The damper member is an elastic member provided on a surface opposite to a surface of the substrate on which the nozzle plate is provided, and multiple cylindrical damper chambers having the same inner diameter as each pressure chamber is provided in a manner of respectively facing each pressure chamber. The common chamber (common channel) communicates with each pressure chamber via each damper chamber of the damper member.[Summary of Invention][Technical Problem]

[0004] However, the conventional liquid discharge head has a problem that discharge failure is likely to occur.[Solution to Problem]

[0005] In an aspect of the present disclosure, a liquid discharge head includes: a nozzle forming wall having multiple nozzles from each of which a liquid is dischargeable in a discharge direction; multiple individual channels respectively having: multiple first faces each formed by the nozzle forming wall and respectively communicating with the multiple nozzles; and multiple second faces respectively opposite to the multiple first faces in the discharge direction, the multiple second faces respectively having multiple openings; multiple actuators driven todischarge the liquid in the multiple individual channels from the multiple nozzles, respectively; a first common channel including first multiple common-branch channels partitioned from each other by a first partition wall; and a second common channel including second multiple common-branch channels partitioned from each other by a second partition wall, wherein one of the multiple openings of the multiple second faces of the multiple individual channels faces one of the first multiple common-branch channels and one of the second multiple common-branch channels.[Effects of the Invention]

[0006] According to the present embodiment, it is possible to suppress discharge failure in the liquid discharge head in which the common channel is provided in a manner of facing the opening of each individual channel located on the side facing the nozzle forming wall.[Brief Description of Drawings]

[0007] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.[FIG. 1]FIG. 1 is a cross-sectional view schematically illustrating a liquid discharge head according to a first embodiment.[FIGS. 2A to 2C]FIG. 2A is an explanatory diagram illustrating an example in which an actuator is disposed on a nozzle plate. FIG. 2B is an explanatory diagram illustrating an example in which the actuator is disposed in the nozzle plate. FIG. 2C is an explanatory diagram illustrating an example in which the actuator is disposed in the vicinity of the nozzle plate.[FIG. 3]FIG. 3 is an enlarged cross-sectional view illustrating a peripheral configuration of one individual channel in the liquid discharge head of the first embodiment.[FIGS. 4 A to 4C]FIGS. 4A to 4C are exploded views of the liquid discharge head.[FIG. 5]FIG. 5 is an explanatory diagram of a common channel of a common channel substrate in the liquid discharge head as viewed from an individual channel side.[FIG. 6]FIG. 6 is an explanatory diagram illustrating a common channel substrate in the liquid discharge head.[FIG. 7]FIG. 7 is an explanatory diagram illustrating an example of a common channel substrate in which a supply common channel and a discharge common channel are arranged near ends on the same side in a nozzle array direction (left-right direction in the drawing).[FIG. 8]FIG. 8 is a cross-sectional view schematically illustrating a liquid discharge head according to a first modification.[FIG. 9]FIG. 9 is a cross-sectional view schematically illustrating a liquid discharge head according to a second modification.[FIG. 10]FIG. 10 is a cross-sectional view schematically illustrating a liquid discharge head according to a third modification.[FIGS. HA to 11D]FIGS. 11A to 1 ID are exploded views of the liquid discharge head.[FIG. 12]FIG. 12 is an explanatory diagram illustrating a common channel substrate in the liquid discharge head.[FIG. 13]FIG. 13 is an explanatory diagram illustrating an example in which an upper wall is formed in a communication channel of the common channel substrate in the liquid discharge head. [FIGS. 14A and 14B]FIGS. 14A and 14B are cross-sectional views each illustrating an example of the upper wall. [FIG. 15]FIG. 15 is a cross-sectional view schematically illustrating an example in which only a peripheral edge of a damper member adheres to an upper surface portion of a common channel substrate in the liquid discharge head.[FIGS. 16A to 16D]FIGS. 16A to 16D are exploded views of a liquid discharge head according to a fourth modification.[FIG. 17]FIG. 17 is an explanatory diagram illustrating a common channel substrate in the liquid discharge head.[FIGS. 18A to 18D]FIGS. 18A to 18D are exploded views of a liquid discharge head according to a fifth modification.[FIG. 19]FIG. 19 is an explanatory diagram illustrating a common channel substrate in the liquid discharge head.[FIGS. 20A to 20C]FIG. 20A is an explanatory diagram illustrating an example of use of forward circulation in which liquid is supplied from a supply common channel of a liquid discharge head and is circulated so as to be discharged from a discharge common channel. FIG. 20B is an explanatory diagram illustrating an example of use of backward circulation in which liquid issupplied from a discharge common channel of a liquid discharge head and is circulated so as to be discharged from a supply common channel. FIG. 20C is an explanatory diagram illustrating an example of use in non-circulation (unidirectional supply) in which liquid is only supplied to the common channel of the liquid discharge head and is not discharged from the liquid discharge head.[FIG. 21]FIG. 21 is a block diagram illustrating an example of a liquid circulation device which is capable of switching among the forward circulation, the backward circulation, and the noncirculation (unidirectional supply).[FIGS. 22 A to 22F]FIGS. 22 A to 22F are explanatory diagrams illustrating an operation example in which opening and closing states of a first switching valve and a second switching valve in the liquid circulation device are schematically illustrated in states of switches (SW1, SW2).[FIGS. 23 A and 23B]FIG. 23A is a cross-sectional view schematically illustrating a liquid discharge head of a first comparative example used in a simple experiment for evaluating whether a filling property of liquid is good or bad. FIG. 23B is a cross-sectional view schematically illustrating a liquid discharge head of a second comparative example used in the simple experiment.[FIG. 24]FIG. 24 is an explanatory diagram illustrating a common channel substrate of a liquid discharge head according to an example of a configuration in which some comers of a common channel are rounded.[FIG. 25]FIG. 25 is a cross-sectional view schematically illustrating a liquid discharge head according to a second embodiment.[FIG. 26]FIG. 26 is an explanatory diagram when an individual channel side is viewed from a common channel substrate side in the liquid discharge head.[FIG. 27]FIG. 27 is an explanatory diagram illustrating another example of channel cross-sectional areas of two fluid resistance members in the liquid discharge head.[FIG. 28]FIG. 28 is an explanatory diagram illustrating another example on the number of two fluid resistance members in the liquid discharge head.[FIG. 29]FIG. 29 is a schematic explanatory diagram of a printing apparatus according to an embodiment.[FIG. 30]FIG. 30 is an explanatory plan view of an example of a head device of the printing apparatus. [FIG. 31]FIG. 31 is an explanatory plan view of a main part of another printing apparatus. [FIG. 32]FIG. 32 is an explanatory side view of a main part of the printing apparatus of the present example.[FIG. 33]FIG. 33 is an explanatory plan view of a main part of the liquid discharge device of the present example.[FIG. 34]FIG. 34 is an explanatory front view of the liquid discharge device of the present example. The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments]

[0008] 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.A description is given below of one embodiment in which the present embodiment is applied to a liquid discharge head installed in a liquid discharge apparatus.Note that the following embodiments are not limiting the present embodiment and any change can be made within a scope that a person skilled in the art can conceive of, including deletion, addition, modification, etc. of other embodiments, and any embodiment is included within the scope of the present embodiment as long as the action and effect of the present embodiment are demonstrated.

[0009] First EmbodimentFIG. 1 is a cross-sectional view schematically illustrating a nozzle plate vibration type liquid discharge head according to a first embodiment.A liquid discharge head 1 according to the first embodiment is a nozzle plate vibration type liquid discharge head that discharges a liquid in an individual channel 4 from a nozzle 2 by varying the pressure in the individual channel 4 by the actuator 5 provided on a nozzle plate 110 (nozzle forming wall) having the nozzle. The nozzle plate vibration type is characterized in that droplets can be splashed with a smaller force than a general unimorph piezo head (which discharges liquid by vibrating surface of pressure chamber facing wall(nozzle forming wall) with which nozzle communicates), and thereby achieving power saving of the actuator.

[0010] In the first embodiment, an example of the nozzle plate vibration type liquid discharge head 1 will be described. However, in the present embodiment, there is no limitation on a driving method or the like as long as the liquid discharge head is provided with a common channel 3 in a manner of facing an opening 4a of the individual channel 4 located on the side facing the nozzle plate 110 (nozzle forming wall).

[0011] For example, an actuator of a nozzle plate vibration type liquid discharge head may be disposed on the nozzle plate 110 (nozzle forming wall) as illustrated in FIG. 2A, may be disposed in the nozzle plate 110 as illustrated in FIG. 2B, or may be disposed in the vicinity of the nozzle plate 110 (in the vicinity of the nozzle plate 110 in the individual channel 4) as illustrated in FIG. 2C. As illustrated in FIGS. 2A and 2B, the actuator may be a piezoelectric element 5 which is an electromechanical transducer that displaces the nozzle plate 110 (nozzle forming wall) as indicated by an arrow A in the drawing, or a thermomechanical transducer such as bimetal. Alternatively, as illustrated in FIG. 2C, the actuator may be replaced with a driving unit such as a heater element 5' that is generatable a bubble B in the liquid in the individual channel 4.

[0012] In any of the configurations of the actuators illustrated in FIGS. 2A to 2C, the channel configuration is simplified, and the channel configuration from the individual channel 4 to the nozzle 2 can be manufactured with one component. Therefore, it is easy to realize a small, high-density, low-cost, and high-definition liquid discharge head.

[0013] The liquid discharge head 1 of the first embodiment includes the nozzle plate 110, an individual channel substrate 100, a common channel substrate 120, and a frame 140. The nozzle plate 110 has a thin film shape, and includes multiple nozzles 2 that discharge liquid, and includes the piezoelectric element 5 as the electromechanical transducer which is an annular actuator arranged around each of the nozzles 2. The individual channel substrate 100 is formed with multiple individual channels 4 communicating with the multiple nozzles 2. The nozzle 2 (vibration film 103) is formed on one surface of each individual channel 4, and the opening 4a of the individual channel 4 is disposed on a side facing the one surface. The common channel substrate 120 has the common channel 3 communicating with the multiple individual channels 4.

[0014] FIG. 3 is an enlarged cross-sectional view illustrating a peripheral configuration of one individual channel 4.The individual channel substrate 100 is a silicon on insulator (SOI) substrate, and includes a drive circuit 101 and a wiring 102 on the side on which the vibration film 103 is formed.The drive circuit 101 is a circuit including a transistor, a resistor, and the like. The wiring 102 includes a wiring for applying a drive waveform to a first electrode 51 of the piezoelectric element 5 and a wiring for applying a drive waveform to a second electrode 53 of the piezoelectric element 5. In addition, the wiring 102 is electrically connected to an electrical connection pad 55 via a third contact 7c opened on the vibration film 103. An electrical component such as an external power supply is connected to the electrical connection pad 55.

[0015] The nozzle plate 110 includes a nozzle forming member (film) 111 in which multiple nozzles 2 is formed and which covers the piezoelectric element 5, and a liquid -repellent film 112 is formed on a nozzle surface of the nozzle forming member 111. When the discharge of the liquid is continued, the mist generated at the same time as the discharge adheres to the nozzle surface.When a large amount of the mist adheres to the nozzle surface, the liquid discharged from the nozzle 2 may be affected by the liquid adhering to the nozzle surface and deviates from a desired landing position. By forming the liquid-repellent film 112 on the nozzle surface, adhesion of liquid to the nozzle surface can be suppressed, and influence of liquid adhered to the nozzle surface on liquid discharged from the nozzle 2 can be suppressed.

[0016] The piezoelectric element 5 of the nozzle plate 110 includes the first electrode 51 (also referred to as lower electrode), a piezoelectric film 52, and the second electrode 53 (also referred to as upper electrode). The piezoelectric element 5 is covered with a first insulating film 8a. A hole-shaped fourth contact 7d for making electrical connection to the first electrode 51 and a hole-shaped fifth contact 7e for making electrical connection to the second electrode 53 are on the first insulating film 8a.

[0017] A first lead-out wiring 9a that electrically connects the first electrode 51 of the piezoelectric element 5 and the wiring 102 of the individual channel substrate 100 and a second lead-out wiring 9b that electrically connects the second electrode 53 of the piezoelectric element 5 and the wiring 102 of the individual channel substrate 100 are on the first insulating film 8a.

[0018] The first lead-out wiring 9a is electrode-like connected to the first electrode 51 via the fourth contact 7d and electrode-like connected to the wiring 102 via the first contact 7a. The second lead-out wiring 9b is electrode-like connected to the second electrode 53 via the fifth contact 7e, and electrode-like connected to the wiring 102 via the second contact 7b. The first lead-out wiring 9a and the second lead-out wiring 9b are covered with the second insulating film 8b. In the first embodiment, the second insulating film 8b also covers the piezoelectric element 5, and has a function of protecting the piezoelectric element 5 by preventing moisture entering the nozzle forming member 111 made of resin from entering the piezoelectric element 5.

[0019] A lead-out wiring may be provided on each of the first electrode 51 and the second electrode 53, and the lead-out wiring may be directly electrode-like connected to the wiring 102 via a contact opened on the vibration film. An adhesion improving film for securing adhesion to the nozzle forming member 111 may be formed on the second insulating film 8b.

[0020] In general, lead zirconate titanate (PZT) is widely used as a material of a piezoelectric element used as an actuator because of high piezoelectric characteristics. However, when a piezoelectric film of the piezoelectric element 5 is formed on a substrate on which the drive circuit 101 and the wiring 102 are formed as in the liquid discharge head 1 of the first embodiment, PZT requires a film formation / crystallization temperature of 600°C or higher. Therefore, when PZT is used as the material of the piezoelectric element 5, the drive circuit 101 and the wiring 102 in the substrate cannot withstand high temperatures. Therefore, in the configuration in which the wiring 102 and the drive circuit 101 are formed on the same substrate as the piezoelectric element 5, a piezoelectric material having a lower film formation temperature than PZT is required as the piezoelectric material. A piezoelectric material having a low film formation temperature often has lower piezoelectric characteristics than PZT. However, in the case of the nozzle plate vibration type described above, liquid can be discharged with a smaller force than a general unimorph piezo head. Therefore, a material having lower piezoelectric characteristics than PZT can be selected. Therefore, even a piezoelectric material such as a non-lead material having a low film formation / crystallization temperature and low power can be used to discharge the liquid satisfactorily. Therefore, as the piezoelectric element 5 in the first embodiment, a piezoelectric element such as aluminum nitride (AIN) or scandium-doped aluminum nitride (ScAlN) containing AIN can be adopted.

[0021] The liquid filled in the liquid discharge head 1 enters the nozzle 2 and forms a meniscus in the nozzle. By applying a predetermined drive waveform (voltage) to each of the electrodes 51 and 53 of the piezoelectric element 5, the piezoelectric film 52 vibrates, and the vibration film 103 vibrates in the up-down direction of FIG. 3. When the vibration film 103 vibrates, a pressure change occurs in the liquid in the individual channel 4, and the liquid is discharged from the nozzle 2.

[0022] Further, in the liquid discharge head 1 of the first embodiment, a protective film 11 as a surface layer that is lyophilic to the liquid discharged by the liquid discharge head 1 and prevents erosion of the liquid is formed on the inner peripheral surface of the nozzle 2, the inner peripheral surface of the individual channel 4, and the bottom surface of the common channel 3. In the first embodiment, the liquid discharged by the liquid discharge head 1 is alkaline, and the individual channel substrate 100 and the vibration film 103 forming the individual channel 4 are made of a silicon film, a silicon-based insulating film, a metal oxide film, a laminated film thereof, or the like. These materials are vulnerable to alkaline liquids and are eluted and eroded by alkaline solutions. In order to prevent this, the individualchannel substrate 100 and the vibration film 103 can be protected from the liquid by forming the liquid resistant protective film 11 that prevents erosion of the liquid.

[0023] The individual channel 4 and the nozzle 2 are formed by dry etching. When the dry etching gas contains fluorine, a surface film containing fluorine is formed on the inner wall surface of the individual channel 4 and the inner peripheral surface of the nozzle 2 after etching, and the inner wall surface of the individual channel 4 and the nozzle inner peripheral surface have liquid repellency. When the inner peripheral surface of the individual channel 4 has liquid repellency, the liquid does not wet-spread on the inner peripheral surface of the individual channel 4 at the time of filling the liquid. Therefore, the individual channel 4 may not be satisfactorily filled with the liquid, and air bubbles may be generated at corners of the individual channel 4.

[0024] In the first embodiment, the protective film 11 which is lyophilic is formed on the inner peripheral surface of the individual channel 4 and the inner peripheral surface of the nozzle 2, and thus, wettability of liquid to the inner peripheral surfaces of the individual channel 4 and the nozzle 2 can be improved. The protective film 11 only needs to be lyophilic to liquid more than the film formation surface of the individual channel 4 or the nozzle 2 (the lower layer surface of the protective film 11) on which the protective film 11 is formed. When the liquid solvent is aqueous, a highly hydrophilic protective film is used, and when the liquid solvent is oily, a highly lipophilic protective film is used, whereby the highly lyophilic protective film 11 can be formed.

[0025] As described above, by forming the protective film 11 which is lyophilic to the liquid filled in the individual channel 4 on the inner peripheral surfaces of the nozzle 2 and the individual channel 4, the liquid easily wet-spreads on the inner peripheral surfaces of the individual channel 4 and the nozzle 2 at the time of filling the liquid. As a result, the filling property of liquid can be improved, and the individual channel 4 and the nozzle 2 can be favorably filled with the liquid without pressurization or suction at the time of filling the liquid. Therefore, it is possible to suppress the occurrence of cracks in the vibration film 103 at the time of filling the liquid.

[0026] Since the liquid solvent of the first embodiment is aqueous, by forming the protective film 11 not containing at least fluorine on the inner peripheral surfaces of the individual channel 4 and the nozzle 2, the lyophilic property can be improved as compared with the surface film containing fluorine formed by dry etching. In addition to the above, since this film is in direct contact with various liquids, it is desirable to use a material having liquid resistance, for example, an oxide of a metal forming a passive state. Furthermore, as a method for improving lyophilicity, a mixture of the metal oxide forming the passive state with silicon dioxide (SiCh) at a molecular level can also be used. SiCh of the protective film 11 has ahydrophilic OH group, with O of its surface being substituted. Thus, hydrophilicity can be further imparted to the protective film 11. Examples of the metal of the metal oxide include tantalum (Ta), niobium (Nb), titanium (Ti), zirconium (Zr), hafnium (Hf), and tungsten (W), which exhibit high compatibility with their oxidation states. In particular, Zr or Hf having a valence similar to that of SiO2, or Ta having a valence around that of SiO2 is particularly desirable.

[0027] In addition, for example, the protective film 11 may have a two-layer structure of a liquidresistant film and a lyophilic film. In this case, after a liquid-resistant film is formed on the inner peripheral surfaces of the nozzle 2 and the individual channel 4, a lyophilic film is formed on the liquid-resistant film.

[0028] The material of the vibration film 103 may be any material that has at least an insulating property, such as SiCh, SiN, metal oxide, or resin. However, in order to increase the displacement, a material having a low Young's modulus is desirable, and considering the difference in linear expansion coefficient from the individual channel substrate 100, SiCh (silicon dioxide) having a relatively small difference in linear expansion coefficient is most desirable as the material of the vibration film 103.

[0029] The first electrode layer 151 and the second electrode layer 153 are desirably made of a metal having low electric resistance and low reactivity, and are desirably made of a metal such as Ir or Mo. As the piezoelectric material constituting a piezoelectric layer 152, when the drive circuit 101 and the wiring 102 are incorporated in the individual channel substrate 100 to improve the density as in the first embodiment, a piezoelectric material having a film formation temperature of 450°C or lower is desirable in order not to break the drive circuit 101 and the wiring 102. Examples of the piezoelectric material having a film formation temperature of 450°C or lower include AIN or ScAlN having a piezoelectric constant higher than that of AIN.

[0030] Further, by using ScAlN as the piezoelectric material, the following advantages can also be obtained. That is, it is possible to improve the piezoelectric characteristics by aligning the crystal orientation of the piezoelectric film 52, but it is necessary to provide an orientation control layer between the vibration film 103 and the first electrode 51 in order to control the orientation. When the piezoelectric material of the piezoelectric film 52 is ScAlN, the lattice constant of the first electrode 51 made of Mo can be made close to ScAlN by using ScAlN also as the orientation control layer. As a result, the crystal orientation of the piezoelectric film 52 is uniform, and the piezoelectric characteristics can be improved.

[0031] FIGS. 4A to 4C are exploded views of the liquid discharge head 1 according to the first embodiment, in which FIG. 4A illustrates the frame 140, FIG. 4B illustrates the commonchannel substrate 120, and FIG. 4C illustrates a drive substrate in which the individual channel substrate 100 and the nozzle plate 110 are integrated.FIG. 5 is an explanatory diagram of the common channel 3 of the common channel substrate 120 of the first embodiment as viewed from the individual channel 4 side.

[0032] In the individual channel substrate 100, as illustrated in FIG. 4C, multiple individual channels 4 is formed to be arranged in a two-dimensional direction so as to correspond to the multiple nozzles 2 formed in the nozzle plate 110. Specifically, on the nozzle plate 110, multiple nozzle arrays (8 arrays in the illustrated example) in which the nozzles 2 are linearly arranged along the left-right direction in the drawing is arranged in the up-down direction in the drawing. Therefore, as illustrated in FIGS. 4A to 4C, multiple arrays of (8 arrays in the illustrated example) individual channels 4, which are formed in the individual channel substrate 100 and arranged along the left-right direction in the drawing, is arranged in the up- down direction in the drawing.

[0033] Note that the nozzles of the respective nozzle arrays are arranged in a manner that the positions in the nozzle array direction (left-right direction in the drawing) are shifted from each other so that high-density (for example, 600 dpi, 1000 dpi, 1200 dpi, or the like) dots can be formed in a single pass. Thus, correspondingly, as illustrated in FIG. 4C, the individual channels 4 are also arranged in a manner that the positions in the left-right direction in the drawing are shifted from each other among the arrays.

[0034] In addition, the individual channel 4 of the first embodiment has been described as an example in which the cross-sectional shape parallel to the substrate surface direction is a circular shape, but the cross-sectional shape may be another shape such as an elliptical columnar shape or a polygonal columnar shape. Further, the cross-sectional shape does not need to be a uniform cross section in the substrate thickness direction.

[0035] As illustrated in FIG. 5, the opening 4a of each individual channel 4 is opened on the upper surface (the surface on the common channel 3 side) of the individual channel substrate 100, and the common channel 3 formed in the common channel substrate 120 is arranged in a manner of facing the opening 4a of each individual channel 4.

[0036] In the first embodiment, the opening 4a of each individual channel 4 faces two common channels 3 a and 3b partitioned from each other by a common channel partition wall 120a. In other words, the opening 4a of each individual channel 4 is divided into 2 opening portions by the common channel partition wall 120a. In the first embodiment, one common channel 3 a facing the opening 4a of the individual channel 4 is a supply common channel for supplying liquid to the individual channel 4, and the other common channel 3b facing the opening 4a ofthe individual channel 4 is a discharge common channel for discharging liquid from the individual channel 4.

[0037] As illustrated in FIG. 4B, the common channel 3 formed in the common channel substrate 120 of the first embodiment is configured in a manner that the supply common-branch channel 3 a and the discharge common-branch channel 3b each have a comb-teeth shape, and the comb-teeth portions thereof are fitted to each other.

[0038] Specifically, as illustrated in FIG. 6, 8 individual channels 4 corresponding to 8 nozzles adjacent to each other across the nozzle arrays are coupled to 2 common channels 3a and 3b partitioned by multiple common channel partition walls 120a. The common channel partition walls 120a are arranged side by side in the nozzle array direction (left-right direction in the drawing). The ends of the common channel partition walls 120a in the up-down direction in the drawing are coupled to each other by partition walls 120d. With such a configuration, one of the spaces partitioned by the common channel partition wall 120a and the partition wall 120d constitutes the supply common-branch channel 3 a, and the other constitutes the discharge common-branch channel 3b.

[0039] The common channel substrate 120 includes a high-precision processed component, and is formed by a MEMS process or a semiconductor process such as photolithography or deep reactive-ion etching (DRIE) on a silicon (Si) substrate (Si wafer) according to the first embodiment. A wetted film (TaOx, HfOx, or the like) having elution resistance to liquid is formed on a wall surface of a channel (common channels 3a and 3b, channel inlet 3c, and channel outlet 3d) formed in the common channel substrate 120. Note that the common channel substrate 120 is not limited thereto, and for example, a substrate obtained by processing a steel use stainless (SUS) plate or a glass substrate by high-precision grinding processing, high-precision pressing processing, sandblasting, or the like may be used.In addition, the common channel substrate 120 may be manufactured by Ni electroforming using photolithography similar to the semiconductor process.

[0040] The frame 140 illustrated in FIG. 4A is provided on an upper surface of the common channel substrate 120 (a surface opposite to the individual channel substrate 100). A liquid stored in an external liquid storage is supplied to the liquid discharge head 1 through a liquid supply port of the frame 140. The liquid supplied from the liquid supply port is supplied from the supply liquid storage chamber 31 in the frame 140 to the channel inlet 3c arranged on one end side (one end side in the nozzle array direction, the left side in the drawing) of the common channel substrate 120 through a supply communication path 32. Thereafter, as indicated by an arrow Cl in FIG. 6, the liquid supplied to the channel inlet 3c flows along the upper surface of the individual channel substrate 100 through the comb-teeth-shaped supply common-branch channel 3 a, and is supplied to each individual channel 4 from an openingportion (supply port) on a side facing the supply common-branch channel 3a in the opening 4a of each individual channel 4 of the individual channel substrate 100.

[0041] In addition, of the liquid in each individual channel 4, the liquid that has not been discharged from the nozzle 2 is discharged from the opening portion (discharge port) of the opening 4a of each individual channel 4 on the side facing the discharge common-branch channel 3b to the discharge common-branch channel 3b. The liquid discharged from each individual channel 4 flows along the upper surface of the individual channel substrate 100 through the discharge common-branch channel 3b, and is discharged from the channel outlet 3d disposed on the other end side (the other end side in the nozzle array direction, the right side in the drawing) of the common channel substrate 120 to the discharge liquid storage chamber 35 in the frame 140. The liquid discharged to the discharge liquid storage chamber 35 is returned from the liquid discharge port of the frame 140 to an external ink storage via an external pump or the like. That is, the liquid discharge head 1 of the first embodiment is a liquid circulation type liquid discharge head.A liquid discharge head includes: a nozzle forming wall having multiple nozzles from each of which a liquid is dischargeable in a discharge direction; multiple individual channels respectively having: multiple first faces each formed by the nozzle forming wall and respectively communicating with the multiple nozzles; and multiple second faces respectively opposite to the multiple first faces in the discharge direction, the multiple second faces respectively having multiple openings; multiple actuators driven to discharge the liquid in the multiple individual channels from the multiple nozzles, respectively; a first common channel including first multiple common-branch channels partitioned from each other by a first partition wall; and a second common channel including second multiple common-branch channels partitioned from each other by a second partition wall, wherein one of the multiple openings of the multiple second faces of the multiple individual channels faces one of the first multiple common-branch channels and one of the second multiple common-branch channels.

[0042] According to the liquid circulation type liquid discharge head, it is possible to circulate the liquid in the common channel 3 and the individual channel 4. As a result, air bubbles present in the channels in the liquid discharge head 1 such as the common channel 3 and the individual channel 4 can be removed, or sedimentation of a liquid component in the channels in the liquid discharge head 1 can be suppressed in the case of using a liquid having a component that is likely to settle.

[0043] It is possible to appropriately set how to arrange the channel inlet 3c and the channel outlet 3d (the supply liquid storage chamber 31 and the discharge liquid storage chamber 35) with respect to the supply common-branch channel 3 a and the discharge common-branch channel 3b. In the first embodiment, the supply common-branch channel 3 a and the discharge common-branch channel 3b are disposed near the ends opposite to each other in the nozzlearray direction (the left-right direction in the drawing). However, for example, as illustrated in FIG. 7, the supply common-branch channel 3a and the discharge common-branch channel 3b may be disposed near the ends on the same side in the nozzle array direction (the left-right direction in the drawing).

[0044] According to the first embodiment, with respect to the opening 4a of the individual channel 4, it is possible to create a flow for allowing liquid to flow from the supply common-branch channel 3 a into the opening 4a and a flow for allowing liquid to flow out from the opening 4a to the discharge common-branch channel 3b, and it is possible to create a flow for exchanging liquid in the individual channel 4. Therefore, the movement of the liquid in the individual channel 4 can be made active, air bubbles in the individual channel 4 can be easily moved and discharged from the individual channel 4, and the occurrence of discharge failure can be suppressed.

[0045] According to the first embodiment, the common channel 3 formed in the common channel substrate 120 is divided into multiple (two in the first embodiment) common channels 3a and 3b by the common channel partition wall 120a. Therefore, the number of individual channels 4 coupled to each of multiple common channels 3 a and 3b is smaller than that in the conventional configuration in which all individual channels 4 are coupled to a single common channel.Therefore, in each individual channel 4, the number of surrounding individual channels 4 coupled to the same common channels 3a and 3b is reduced, and crosstalk that causes discharge failure of the nozzle 2 of each individual channel 4 is suppressed.

[0046] Describing the crosstalk here, when the piezoelectric element 5 of the nozzle plate 110 vibrates the vibration film 103 to apply pressure to the liquid in the individual channel 4, the pressure becomes a force for discharging the liquid from the nozzle 2, but a part of the pressure escapes from the opening 4a of the individual channel 4 to the common channel side. The escaping pressure propagates to surrounding individual channels 4 through the common channel as a pressure wave that causes crosstalk or an inertial flow that causes crosstalk. That is, a pressure wave and an inertial flow, which are from the individual channel 4 and exist around each individual channel 4, propagate through the common channel 3 to each individual channel 4, thereby causing crosstalk that causes discharge failure of the nozzle 2 of each individual channel 4. As in the first embodiment, since the number of surrounding individual channels 4 coupled to the same common channels 3a and 3b is reduced, the influence of the pressure wave and the inertial flow from the surrounding individual channels 4 propagating to each individual channel 4 is reduced, and thus, crosstalk is suppressed.

[0047] In the first embodiment, the number of individual channels 4 coupled to the same common channels 3 a and 3b can be appropriately set, and the arrangement, shape, and the like of eachof the common channels 3a and 3b are appropriately determined accordingly. As the number of individual channels 4 coupled to the same common channels 3 a and 3b is smaller, crosstalk can be suppressed. Note that the influence of crosstalk cannot be uniquely described because the influence degree varies greatly depending on the dimensions and materials (detailed design) of each part. However, as an example, there is a result that the variation in the liquid discharge speed can be suppressed to about 10 to 15% or less by the configuration in which the common channel is divided into multiple channels as in the first embodiment as compared with the conventional liquid discharge head in which the variation in the liquid discharge speed when 100 or more nozzles are simultaneously driven is tens of percent.

[0048] First ModificationNext, one modification (hereinafter, this modification is referred to as "first modification") of the liquid discharge head 1 according to the first embodiment will be described.In the liquid discharge head 1 of the first embodiment described above, one of two common channels 3 a and 3b each facing the respective opening 4a of the individual channel 4 is the supply common channel, and the other is the discharge common channel. The liquid discharge head 1 of the first modification is an example in which the two common channels 3 a and 3b each facing the respective opening 4a of the individual channel 4 are both supply common channels. Since the basic configuration of the liquid discharge head 1 of the first modification is the same as that of the first embodiment described above, redundant description will be appropriately omitted.

[0049] FIG. 8 is a cross-sectional view schematically illustrating a liquid discharge head according to the first modification.Similarly to the first embodiment described above, the liquid discharge head 1 of the first modification also has a configuration in which the common channel 3 formed in the common channel substrate 120 has a comb-teeth shape respectively with the two common channels 3a and 3b as illustrated in FIG. 4B, and the comb-teeth portions are fitted to each other. Here, both the common channels 3a and 3b are supply common channels.

[0050] That is, not only the supply liquid storage chamber 31 but also the discharge liquid storage chamber 35 in the frame 140 functions as the supply liquid storage chamber, and the liquid supplied from the liquid supply port of the frame 140 is supplied from the two liquid storage chambers 31 and 35 in the frame 140 to the channels 3c and 3d arranged near both ends (both ends in the nozzle array direction) of the common channel substrate 120 through the respective communication paths 32 and 34. Thereafter, as indicated by an arrow Cl in FIG. 8, the liquid supplied to each of the channels 3c and 3d flows along the upper surface of the individual channel substrate 100 through each of the comb -teeth- shaped common channels 3a and 3b, and is supplied to each individual channel 4 from both opening portions (openingportions respectively facing each of the common channels 3 a and 3b) in the opening 4a of each individual channel 4 of the individual channel substrate 100.

[0051] In the first modification, as illustrated in FIG. 8, the opening 4a of each individual channel 4 communicates with multiple (here, two) common channels 3 a and 3b partitioned from each other by the common channel partition wall 120a, and liquid is supplied from both of the common channels 3 a and 3b to each individual channel 4. Even if the common channels 3 a and 3b have the same structure, and the opening 4a of the individual channel 4 is divided into completely equal opening portions by the common channel partition wall 120a, the inflow and outflow of liquid between each of the common channels 3 a and 3b and the individual channel 4 are not completely matched between the common channels 3 a and 3b due to a manufacturing error, a difference in position in the liquid discharge head, or the like. Therefore, the inflow and outflow of liquid to and from the individual channel 4 are different between the common channels 3a and 3b, and are asymmetric.Due to such asymmetric inflow and outflow of liquid, more active movement of the liquid can be generated in the individual channel 4 as compared with the conventional configuration in which the entire opening 4a of the individual channel 4 communicates with one common channel.

[0052] As a result, in the first modification, the air bubbles generated at the comers of the individual channel 4 are likely to move from the corners, and the occurrence of discharge failure is suppressed due to, for example, the air bubbles being discharged from the individual channel 4 to the outside via the nozzle 2 during the liquid filling or during operation of the liquid discharge head.

[0053] Second ModificationNext, another modification (hereinafter, this modification is referred to as "second modification") of the liquid discharge head 1 according to the first embodiment will be described.In the liquid discharge head 1 of the first embodiment and the first modification described above, the opening areas or the opening shapes of the opening portions of the individual channels 4 facing the common channels 3a and 3b are the same between the common channels 3 a and 3b. The liquid discharge head 1 of the second modification is an example in which the opening areas or the opening shapes of the opening portions of the individual channels 4 facing the common channels 3a and 3b are different from each other between the common channels 3 a and 3b.

[0054] FIG. 9 is a cross-sectional view schematically illustrating a liquid discharge head according to the second modification.In the liquid discharge head 1 of the second modification, similarly to the first embodiment described above, one of the two common channels 3 a and 3b facing the opening 4a of each individual channel 4 is the supply common-branch channel 3 a, and the other is the discharge common-branch channel 3b. In the common channel substrate 120 of the second modification, as illustrated in FIG. 9, the common channel partition wall 120a extending in a manner of crossing the opening 4a of each individual channel 4 of the individual channel substrate 100 is disposed in a manner of crossing a position shifted from the opening center of the opening 4a. As a result, the opening area of the opening portion of the opening 4a of the individual channel 4 coupled to the discharge common-branch channel 3b is larger than the opening area of the opening portion of the opening 4a of the individual channel 4 coupled to the supply common-branch channel 3a.

[0055] According to the configuration of the second modification, the fluid resistance at the time of outflow of the liquid from the individual channel 4 to the discharge common-branch channel 3b is smaller than the fluid resistance at the time of inflow of the liquid from the supply common-branch channel 3 a to the individual channel 4. In this case, as compared with the configuration in which the opening areas or the opening shapes of the opening portions of the individual channels 4 facing the common channels 3 a and 3b are the same between the common channels 3a and 3b, or as compared with the configuration in which the opening area of the opening portions of the opening 4a of the individual channel 4 coupled to the supply common-branch channel 3 a is larger, the inflow and outflow of liquid to and from the individual channel 4 become smooth, and the movement of the liquid in the individual channel 4 can be made active. Therefore, air bubbles in the individual channel 4 are moved to be easily discharged from the individual channel 4, and occurrence of discharge failure can be further suppressed.

[0056] Third ModificationNext, still another modification (hereinafter, this modification is referred to as "third modification") of the liquid discharge head 1 according to the first embodiment will be described.The liquid discharge head 1 of the third modification is obtained by adding a damper member to the liquid discharge head 1 of the first embodiment described above. Since the basic configuration of the liquid discharge head 1 of the third modification is the same as that of the first embodiment described above, redundant description will be appropriately omitted.

[0057] FIG. 10 is a cross-sectional view schematically illustrating a liquid discharge head according to the third modification.A damper member 130 is provided on an upper surface of the common channel substrate 120 (a surface opposite to the individual channel substrate 100). The damper member 130 is a film member (damper film) made of a material having high flexibility, and is disposed at aposition facing the opening 4a (that is, the upper surface of the individual channel substrate 100) of each individual channel 4 via each of the common channels 3a and 3b. That is, the damper member 130 constitutes one wall (upper wall surface) of each of the common channels 3a and 3b. With such a configuration, the damper member 130 is deformed according to the pressure wave and the inertial flow of the crosstalk propagated to the liquid in each of the common channels 3a and 3b, and the pressure wave and the inertial flow of the crosstalk generated in the common channel 3 can be reduced, thereby exhibiting the effect of suppressing the crosstalk.

[0058] It is preferable that the damper member 130 of the third modification has gas impermeability (property of not passing gas) and moisture impermeability (property of not passing moisture / water molecules). This is to suppress deterioration (change in concentration, viscosity, etc., fixation of solid content, etc.) of the liquid filled in the common channels 3a and 3b. The air-impermeable and moisture-impermeable damper member 130 may be produced, for example, by coating a thin metal film or the like, but is not limited thereto, and is preferably produced using a widely commercially available material.Here, although the damper function is implemented using a damper film, the third modification is not limited thereto.

[0059] FIGS. 11A to 1 ID are exploded views of the liquid discharge head 1 according to the modification 3, in which FIG. 11A illustrates the frame 140, FIG. 11B illustrates the damper member 130, FIG. 11C illustrates the common channel substrate 120, and FIG. 11D illustrates a drive substrate in which the individual channel substrate 100 and the nozzle plate 110 are integrated.As illustrated in FIGS. 11A to 1 ID, the liquid discharge head 1 of the third modification is configured by arranging the nozzle plate 110, the individual channel substrate 100, the common channel substrate 120, the damper member 130, and the frame 140 in this order.

[0060] In the frame 140 of the third modification, an air chamber 131 for securing displacement or vibration of the damper member 130 is formed. The air chamber 131 is opened to the outside air through an atmosphere open hole. As illustrated in FIG. 12, the damper member 130 is provided in a manner of not covering the channels 3c and 3d communicating with the liquid storage chambers 31 and 35 of the frame 140 on the upper surface of the common channel substrate 120. This prevents the damper member 130 from obstructing the flow of liquid between the liquid storage chambers 31 and 35 of the frame 140 and the channels 3c and 3d.

[0061] The damper member 130 is adhered (attached) to a part or the whole of the upper surface portion (the portion where the channels 3a, 3b, 3c, and 3d are not formed) of the common channel substrate 120 with an adhesive 132, for example. It is preferable that when thedamper member 130 is adhered (attached) to the common channel substrate 120, from the viewpoint of the sealing property of each of the channels 3a, 3b, 3c, and 3d of the common channel substrate 120, at least the entire peripheral edge of the damper member 130 is adhered (secured) to the common channel substrate 120.

[0062] In the configuration illustrated in FIG. 12, a part of the peripheral edge of the damper member 130 is disposed in a manner of crossing the communication channels 3e and 3e between the common channels 3a and 3b and the channels 3c and 3d of the common channel substrate 120. At this portion, since the communication channels 3e and 3e of the common channel substrate 120 are open, the peripheral edge of the damper member 130 cannot be adhered to the upper surface portion of the common channel substrate 120 with the adhesive 132. Therefore, in the configuration illustrated in FIG. 12, the sealing property is likely to be insufficient.

[0063] As a method for improving the sealing property, for example, as illustrated in FIG. 13, the upper wall 122 is formed on the communication channels 3e and 3e for communicating the common channels 3a and 3b and the channels 3c and 3d of the common channel substrate 120. By forming the upper wall 122, the entire peripheral edge of the damper member 130 can be adhered to the upper surface portion (including the upper wall 122) of the common channel substrate 120 with the adhesive 132, and sufficient sealing property can be obtained.

[0064] As a method for forming the upper wall 122 of the communication channels 3e and 3e, for example, in a case where the common channel substrate 120 including a Si substrate is manufactured by a semiconductor process, as illustrated in FIG. 14A, the upper wall 122 may be formed by a part of the Si substrate by processing in a manner of leaving a portion of the upper wall 122 by the semiconductor process. In addition, as illustrated in FIG. 14B, a film such as a SiN film may be formed in the portions of the communication channels 3e and 3e, and the film may be used as the upper wall 122. When the thickness of the upper wall 122 is excessively increased, the cross-sectional areas of the communication channels 3e and 3e are narrowed, and the fluid resistance of the communication channels 3e and 3e is increased. Therefore, the thickness of the upper wall 122 is set in consideration of the balance between the required rigidity of the upper wall 122 and the required fluid resistance of the communication channels 3e and 3e.

[0065] When the liquid discharge head 1 is used as an inkjet print head, the liquid discharge head 1 is often driven to discharge liquid from multiple or all of the nozzles 2 simultaneously. When the multiple nozzles 2 is simultaneously driven, as described above, the pressure wave or the inertial flow generated in each individual channel 4 is transmitted to each of the common channels 3a and 3b. Furthermore, there is vibration transmitted to the head housing itself by driving. The pressure wave or the inertial flow (also referred to as vibration) transmittedfrom a large number of individual channels 4 to each of the common channels 3 a and 3b becomes a complicated composite wave, and a phenomenon in which the composite wave propagates to each individual channel 4 by diffraction, reflection, or the like is referred to as crosstalk. When the phenomenon becomes remarkable, discharge failure from each of the nozzles 2 is caused.

[0066] The damper member 130 in the third modification attenuates the pressure wave or the inertial flow (vibration) transmitted to each of the common channels 3a and 3b, and the ease of attenuation is generally expressed as high compliance (reception amount). Therefore, it is preferable that the movement of the damper member 130 is unrestricted as much as possible, and the larger the securing interval of the damper member 130 (the distance between the portions adhered to the upper surface portion of the common channel substrate 120), the larger the compliance.

[0067] As illustrated in FIG. 10, in the damper member 130 of the third modification, not only the peripheral edge of the damper member 130 but also the inner portion of the damper member 130, specifically, the upper surface portion of the common channel partition wall 120a that partitions the two common channels 3 a and 3b and the upper surface portion of the partition wall 120d that couples the respective ends of the common channel partition wall 120a, are adhered with the adhesive 132. In this case, the securing interval of the damper member 130 is not large, the compliance is small, and the damper function may be insufficient. In such a case, as illustrated in FIG. 15, only the peripheral edge of the damper member 130 may be adhered to the upper surface portion of the common channel substrate 120 with the adhesive 132.

[0068] In the example of FIG. 15, when the inside of each of the common channels 3a and 3b is in a negative pressure state, as indicated by a solid line in FIG. 15, the damper member 130 is in a state in which the inner portion of the damper member 130 is also in close contact with the upper surface portion of the common channel partition wall 120a or the upper surface portion of the partition wall 120d. Therefore, a state in which the common channels 3a and 3b are partitioned from each other is maintained. In general, in order to prevent leakage of liquid from the nozzle 2, a weak negative pressure is set in the individual channel 4, and a weak negative pressure is also set in each of the common channels 3a and 3b communicating therewith. Therefore, in a normal use state, the damper member 130 is also in close contact with the upper surface portion of the common channel partition wall 120a and the upper surface portion of the partition wall 120d, and a state in which the common channels 3 a and 3b are partitioned from each other is maintained.

[0069] The method for maintaining the inside of the channel at a negative pressure can be implemented, for example, by arranging the liquid level of the liquid storage outside theliquid discharge head 1 at a position lower than the position of the nozzle 2. Alternatively, for example, a sponge-like material may be filled in a liquid storage or the like outside the liquid discharge head 1, and a negative pressure may be formed by the holding force thereof to implement the method. At the time of liquid filling of the liquid discharge head 1, if liquid is filled by a method for sucking a side of any of the common channels 3 a and 3b (for example, the discharge common-branch channel 3b) by an external pump, the damper member 130 can perform the liquid filling while maintaining the close contact state with the upper surface portion of the common channel partition wall 120a and the upper surface portion of the partition wall 120d and maintaining the state in which the common channels 3 a and 3b are partitioned from each other.

[0070] On the other hand, in the example of FIG. 15, when the pressure wave or the inertial flow generated in each individual channel 4 by driving propagates into each of the common channels 3a and 3b, the inner portion of the damper member 130 can be displaced away from the upper surface portion of the common channel partition wall 120a or the upper surface portion of the partition wall 120d as indicated by a broken line in FIG. 15. That is, since the securing interval of the damper member 130 is large, compliance is large, and a high damper function can be exhibited.

[0071] The third modification is an example in which one of the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 is the supply common channel and the other is the discharge common channel, similarly to the first embodiment described above, but the third modification is not limited thereto. For example, as in the liquid discharge head 1 of the first modification described above, the third modification can also be applied to an example in which the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 are both supply common channels.

[0072] Fourth ModificationNext, still another modification (hereinafter, this modification is referred to as “fourth modification") of the liquid discharge head 1 according to the first embodiment will be described.The liquid discharge head 1 of the fourth modification also has a configuration including the damper member 130 similarly to the third modification described above, but is different from the third modification described above in that the liquid storage chambers 31 and 35 of the frame 140 and the channels 3c and 3d of the common channel substrate 120 have different configurations. Since the basic configuration of the liquid discharge head 1 of the fourth modification is the same as that of the third modification described above, redundant description will be appropriately omitted.

[0073] FIGS. 16A to 16D are exploded views of the liquid discharge head 1 according to the fourth modification, in which FIG. 16A illustrates the frame 140, FIG. 16B illustrates the damper member 130, FIG. 16C illustrates the common channel substrate 120, and FIG. 16D illustrates a drive substrate in which the individual channel substrate 100 and the nozzle plate 110 are integrated.As illustrated in FIGS. 16A to 16D, the liquid discharge head 1 of the fourth modification is configured by arranging the nozzle plate 110, the individual channel substrate 100, the common channel substrate 120, the damper member 130, and the frame 140 in this order.

[0074] In the fourth modification, the liquid storage chambers 31 and 35 formed in the frame 140 have substantially L shapes as illustrated in FIG. 16A. Thus, the liquid storage chambers 31 and 35 of the frame 140 face not only the channels 3cl and 3dl arranged in the vicinity of the ends of the common channel substrate 120 in the nozzle array direction (the left-right direction in the drawing) but also the channels 3c2 and 3d2 extending along and in the vicinity of the ends of the common channel substrate 120 in the direction perpendicular to the nozzle array direction (the up-down direction in the drawing). In the third modification described above, the liquid storage chambers 31 and 35 of the frame 140 communicate only with the channels 3cl and 3dl of the common channel substrate 120, but in the fourth modification, the liquid storage chambers 31 and 35 of the frame 140 communicate with not only the channels 3cl and 3dl of the common channel substrate 120 but also the channels 3c2 and 3d2.

[0075] According to the fourth modification, the liquid flowing from the supply liquid storage chamber 31 in the frame 140 into the channel inlet 3c2 of the common channel substrate 120 is also supplied to each of the supply common channels 3a of the common channel substrate 120. Therefore, the path length of the liquid supplied from the supply liquid storage chamber 31 in the frame 140 to each of the supply common channels 3 a is shortened, and the liquid can be more smoothly supplied to each individual channel 4 via each of the supply common channels 3 a.

[0076] Further, according to the fourth modification, the liquid flowing out from each of the discharge common channels 3b of the common channel substrate 120 to the channel outlet 3d2 can be discharged as it is from the channel outlet 3d2 to the discharge liquid storage chamber 35 in the frame 140. Therefore, the path length of the liquid discharged from each of the discharge common channels 3b to the discharge liquid storage chamber 35 in the frame 140 is shortened, and the liquid can be more smoothly discharged from each individual channel 4 via each of the discharge common channels 3b.

[0077] As described above, according to the fourth modification, the flow of the liquid in each of the common channels 3a and 3b can be made smooth, and thus, the movement of the liquid in theindividual channel 4 can also be activated accordingly, air bubbles in the individual channel 4 can be easily moved and discharged from the inside of the individual channel 4, and the occurrence of discharge failure can be suppressed. In particular, according to the fourth modification, the liquid flows smoothly during the liquid filling of the liquid discharge head, and the liquid filling property is improved.

[0078] In addition, the damper member 130 of the fourth modification is provided in a manner of not covering the channels 3c 1, 3dl, 3c2, and 3d2 communicating with the liquid storage chambers 31 and 35 of the frame 140 on the upper surface of the common channel substrate 120 as illustrated in FIG. 17 so as not to obstruct the flow of the liquid described above. At this time, it is preferable that the damper member 130 adheres at least the entire peripheral edge of the damper member 130 from the viewpoint of sealing property.

[0079] Therefore, in the fourth modification, as illustrated in FIG. 17, the upper wall 122 is formed at a portion of communication channels 3f and 3f between the respective common channels 3a and 3b and the channels 3c2 and 3d2 of the common channel substrate 120. By forming the upper wall 122, the entire peripheral edge of the damper member 130 can be adhered to the upper surface portion (including the upper wall 122) of the common channel substrate 120 with the adhesive 132, and sufficient sealing property can be obtained.

[0080] When the thickness of the upper wall 122 is excessively increased, the cross-sectional areas of the communication channels 3f and 3f are narrowed, and the fluid resistance of the communication channels 3f and 3f is increased. Therefore, the thickness of the upper wall 122 is set in consideration of the balance between the required rigidity of the upper wall 122 and the required fluid resistance of the communication channels 3f and 3f.

[0081] The fourth modification is also an example in which one of the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 is the supply common channel and the other is the discharge common channel, similarly to the third modification described above, but the fourth modification is not limited thereto. For example, as in the liquid discharge head 1 of the first modification described above, the fourth modification can also be applied to an example in which the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 are both supply common channels.

[0082] Fifth ModificationNext, still another modification (hereinafter, this modification is referred to as “fifth modification") of the liquid discharge head 1 according to the first embodiment will be described.The liquid discharge head 1 of the fifth modification also has a configuration including the damper member 130 similarly to the third modification and the fourth modification describedabove, but is different from the third modification and the fourth modification described above in that the liquid storage chambers 31 and 35 of the frame 140 and the channels of the common channel substrate 120 have different configurations. Since the basic configuration of the liquid discharge head 1 of the fifth modification is the same as those of the third modification and the fourth modification described above, redundant description will be appropriately omitted.

[0083] FIGS. 18A to 18D are exploded views of the liquid discharge head 1 according to the fifth modification, in which FIG. 18A illustrates the frame 140, FIG. 18B illustrates the damper member 130, FIG. 18C illustrates the common channel substrate 120, and FIG. 18D illustrates a drive substrate in which the individual channel substrate 100 and the nozzle plate 110 are integrated.As illustrated in FIGS. 18A to 18D, the liquid discharge head 1 of the fifth modification is configured by arranging the nozzle plate 110, the individual channel substrate 100, the common channel substrate 120, the damper member 130, and the frame 140 in this order.

[0084] In the fifth modification, the channels 3c and 3d of the common channel substrate 120 communicating with the liquid storage chambers 31 and 35 formed in the frame 140 are disposed not in the vicinity of the ends of the common channel substrate 120 in the nozzle array direction (the left-right direction in the drawing) but in the vicinity of the ends of the common channel substrate 120 in the direction perpendicular to the nozzle array direction (the up-down direction in the drawing). Therefore, the liquid storage chambers 31 and 35 of the frame 140 are formed in the vicinity of the ends in the direction perpendicular to the nozzle array direction (the up-down direction in the drawing) in a manner of facing the channels 3c and 3d formed in the common channel substrate 120.

[0085] In the fifth modification, the supply common channels 3a of the common channel substrate 120 are respectively coupled to the channel inlet 3c of the common channel substrate 120 at different portions in the longitudinal direction (the nozzle array direction, the left-right direction in the drawing) of the channel inlet 3c. In the fifth modification, the liquid in the supply liquid storage chamber 31 of the frame 140 flows substantially uniformly over the entire region in the longitudinal direction of the channel inlet 3 c of the common channel substrate 120. Therefore, the liquid in the supply liquid storage chamber 31 of the frame 140 is supplied to any of the supply common channels 3a through the shortest path. As a result, the liquid can be more smoothly supplied to each individual channel 4 via each of the supply common channels 3 a.

[0086] Further, in the fifth modification, the discharge common channels 3b of the common channel substrate 120 are respectively coupled to the channel outlet 3d of the common channel substrate 120 at different portions in the longitudinal direction (the nozzle array direction, theleft-right direction in the drawing) of the channel outlet 3d. In the fifth modification, the liquid can be caused to flow out substantially uniformly over the entire region in the longitudinal direction of the channel outlet 3d of the common channel substrate 120 with respect to the discharge liquid storage chamber 35 of the frame 140. Therefore, in any of the discharge common channels 3b, the discharge path of the liquid into the discharge liquid storage chamber 35 of the frame 140 is the shortest, and the liquid can be more smoothly discharged from each individual channel 4 via each of the discharge common channels 3b.

[0087] As described above, according to the fifth modification, the flow of the liquid in each of the common channels 3a and 3b can be made smooth, and thus, the movement of the liquid in the individual channel 4 can also be activated accordingly, air bubbles in the individual channel 4 can be easily moved and discharged from the inside of the individual channel 4, and the occurrence of discharge failure can be suppressed. In particular, according to the fourth modification, the liquid flows smoothly during the liquid filling of the liquid discharge head, and the liquid filling property is improved.

[0088] In particular, according to the fifth modification, as in the third modification and the fourth modification described above, it is not necessary to arrange the channels 3c, 3d, 3cl, and 3dl near the two ends (the two ends in the nozzle array direction) of the common channel substrate 120. Therefore, the head in the nozzle array direction can be downsized.

[0089] In addition, the damper member 130 of the fifth modification is also provided in a manner of not covering the channels 3c and 3d communicating with the liquid storage chambers 31 and 35 of the frame 140 on the upper surface of the common channel substrate 120 as illustrated in FIG. 19 so as not to obstruct the flow of the liquid described above. At this time, it is preferable that the damper member 130 adheres at least the entire peripheral edge of the damper member 130 from the viewpoint of sealing property.

[0090] Therefore, as illustrated in FIG. 19, in the fifth modification, similarly to the fourth modification described above, the upper wall 122 is formed at the portions of the communication channels 3f and 3f between the common channels 3a and 3b and the channels 3c and 3d of the common channel substrate 120. By forming the upper wall 122, the entire peripheral edge of the damper member 130 can be adhered to the upper surface portion (including the upper wall 122) of the common channel substrate 120 with the adhesive 132, and sufficient sealing property can be obtained.

[0091] When the thickness of the upper wall 122 is excessively increased, the cross-sectional areas of the communication channels 3f and 3f are narrowed, and the fluid resistance of the communication channels 3f and 3f is increased. Therefore, the thickness of the upper wall122 is set in consideration of the balance between the required rigidity of the upper wall 122 and the required fluid resistance of the communication channels 3f and 3f.

[0092] The fifth modification is also an example in which one of the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 is the supply common channel and the other is the discharge common channel, similarly to the third modification and the fourth modification described above, but the fifth modification is not limited thereto. For example, as in the liquid discharge head 1 of the first modification described above, the fifth modification can also be applied to an example in which the two common channels 3 a and 3b facing each opening 4a of the individual channel 4 are both supply common channels.

[0093] Next, a liquid filling method for filling the liquid discharge head 1 with liquid in the first embodiment (including the modification described above; the same applies hereinafter) will be described.FIG. 20A illustrates an example of use in forward circulation in which liquid is circulated in a manner of being supplied from the supply common-branch channel 3a of the liquid discharge head 1 and discharged from the discharge common-branch channel 3b. FIG. 20B illustrates an example of use in backward circulation in which liquid is circulated in a manner of being supplied from the discharge common-branch channel 3b of the liquid discharge head 1 and discharged from the supply common-branch channel 3a. FIG. 20C illustrates an example of use in non-circulation (unidirectional supply) in which liquid is only supplied to the common channels 3 a and 3b of the liquid discharge head 1 and is not discharged from the liquid discharge head 1.

[0094] A liquid circulation device 200 of the present example includes a main tank 201 that is a liquid storage unit which stores the liquid discharged from the liquid discharge head 1, a main sub tank 231 that is coupled by a circulation path in the drawing, and a main liquid feed pump 204 that feeds the liquid from the main tank 201 to the main sub tank 231.

[0095] The circulation path in the liquid circulation device 200 includes a first sub tank 211, a first liquid feed pump 202 as a first liquid feed unit, a second sub tank 221, a second liquid feed pump 203 as a second liquid feed unit, a foreign substance removing filter 271, a deaerating device 272 (a device for deaerating dissolved gas that causes generation of air bubbles which inhibit liquid feeding and discharge), a first manifold 241, and a second manifold 251.

[0096] One or multiple liquid discharge heads 1 is coupled to the first manifold 241 and the second manifold 251 via a first pressurizing and depressurizing damper 261 and a second pressurizing and depressurizing damper 262, respectively.The first manifold 241 and the second manifold 251 are provided with a first pressure sensor 242 and a second pressure sensor 252 as detection units for detecting the respective pressures.

[0097] The liquid stored in the main tank 201 is fed to the main sub tank 231 by the main liquid feed pump 204 based on a detection result of a liquid level detection unit that detects a liquid level in the main sub tank 231. The first liquid feed pump 202 is disposed in a liquid path passing through a common liquid path, which is coupled to the main sub tank 231, and the first sub tank 211, and feeds liquid toward the first sub tank 211 on the liquid discharge head 1 side. Thus, the liquid is pressurized by the first sub tank 211 and sent to the first manifold 241 (in the case of forward circulation in FIG. 20A) or the second manifold 251 (in the case of backward circulation in FIG. 20B).

[0098] The second liquid feed pump 203 is disposed in a liquid path passing through the common liquid path, which is coupled to the main sub tank 231, and the second sub tank 221, and feeds liquid in a direction of recovering the liquid from the second sub tank 221. Thus, liquid is recovered (discharged) from the second manifold 251 (in the case of forward circulation in FIG. 20A) or the first manifold 241 (in the case of backward circulation in FIG. 20B) to the second sub tank 221 which has been depressurized.

[0099] Here, in the case of the forward circulation of FIG. 20A, the first sub tank 211 is pressurized to a target pressure by the first liquid feed pump 202 based on pressure detection information of the first pressure sensor 242. The first liquid feed pump 202 feeds liquid from the main sub tank 231 to the first sub tank 211 when a pressure value detected by the first pressure sensor 242 becomes lower than a set threshold value. The second sub tank 221 is depressurized to a target pressure by the second liquid feed pump 203 based on pressure detection information of the second pressure sensor 252. The second liquid feed pump 203 feeds liquid from the second sub tank 221 to the main sub tank 231 when a pressure value detected by the second pressure sensor 252 becomes higher than a set threshold value.

[0100] In the case of the backward circulation of FIG. 20B, the first sub tank 211 is pressurized to a target pressure by the first liquid feed pump 202 based on the pressure detection information of the second pressure sensor 252. The first liquid feed pump 202 feeds liquid from the main sub tank 231 to the first sub tank 211 when the pressure value detected by the second pressure sensor 252 becomes lower than a set threshold value. The second sub tank 221 is depressurized to a target pressure by the second liquid feed pump 203 based on the pressure detection information of the first pressure sensor 242. The second liquid feed pump 203 feeds liquid from the second sub tank 221 to the main sub tank 231 when the pressure value detected by the first pressure sensor 242 becomes higher than a set threshold value.

[0101] As described above, the first sub tank 211 is pressurized by liquid feeding by the first liquid feed pump 202, and the second sub tank 221 is depressurized by liquid feeding by the second liquid feed pump 203, whereby a pressure difference is provided between the second sub tank221 and the first sub tank 211, and the liquid is circulated to the liquid discharge head 1 between the first manifold and the second manifold by this pressure difference.

[0102] When the liquid flows from the first sub tank 211 to the second sub tank 221 due to the pressure difference, the pressure of the first sub tank 211 decreases, the pressure sensor (the first pressure sensor 242 in the case of forward circulation in FIG. 20A, the second pressure sensor 252 in the case of backward circulation in FIG. 20B) on the upstream side (pressurizing side) detects the pressure decrease, and the first liquid feed pump 202 operates to replenish the liquid from the main sub tank 231 to pressurize the first sub tank 211.

[0103] Similarly, when the liquid flows from the first sub tank 211 to the second sub tank 221 due to the pressure difference, the pressure of the second sub tank 221 increases (the negative pressure weakens), the pressure sensor (the second pressure sensor 252 in the case of forward circulation in FIG. 20A, the first pressure sensor 242 in the case of backward circulation in FIG. 20B) on the downstream side (depressurizing side) detects the pressure increase, and the second liquid feed pump 203 operates to discharge the liquid to the main sub tank 231 to depressurize the second sub tank 221.

[0104] Here, in a state where the liquid is not consumed by discharge or the like by the liquid discharge head 1, the amount of liquid in the main sub tank 231 does not change significantly. On the other hand, in a state where the liquid is consumed by being discharged or the like by the liquid discharge head 1, the amount of liquid in the main sub tank 231 decreases. Therefore, a decrease in the amount of liquid is detected by a liquid level sensor or the like, and the liquid is replenished and supplied from the main tank 201 to the main sub tank 231 by the main liquid feed pump 204.

[0105] FIG. 21 is a block diagram illustrating an example of the liquid circulation device 200 which is capable of switching among the forward circulation (FIG. 20A), the backward circulation (FIG. 20B), and the non-circulation (unidirectional supply) (FIG. 20C) described with reference to FIG. 20.

[0106] In the liquid circulation device 200 illustrated in FIG. 21, first switching valves 281 A and 28 IB and second switching valves 282A and 282B are disposed between the first sub tank 211 and the second sub tank 221, and the first manifold 241 and the second manifold 251.

[0107] FIGS. 22A to 22F illustrate operation examples which schematically illustrate opening and closing states of the first switching valves 281 A and 28 IB and the second switching valves 282A and 282B in states of switches (SW1, SW2).The state illustrated in FIG. 22A illustrates a state during operation in the forward circulation (A route). In this case, the first switching valve 281 A is opened and the first switching valve28 IB is closed, and the second switching valve 282A is opened and the second switching valve 282B is closed. The state illustrated in FIG. 22E illustrates a state during operation in the backward circulation (B route). In this case, the first switching valve 281 A is closed and the first switching valve 28 IB is opened, and the second switching valve 282A is closed and the second switching valve 282B is opened. FIG. 22C illustrates a state in the middle of switching between the forward circulation (A route) and the backward circulation (B route). In this case, the first switching valves 281 A and 28 IB and the second switching valves 282A and 282B are all closed.

[0108] When the forward circulation (A route) and the backward circulation (B route) are repeatedly performed in a switching manner, the states of the first switching valves 281 A and 28 IB and the second switching valves 282A and 282B may be simply switched in the order of FIG. 22AFIG. 22C FIG. 22E FIG. 22C FIG. 22A FIG. 22C -^... Here, when the pressure in the liquid discharge head 1 instantaneously becomes positive due to a differential pressure state (magnitude of differential pressure) between the first sub tank 211 and the second sub tank 221 or a time difference in valve operation, liquid leakage (dripping) may occur in some cases.

[0109] Therefore, the state illustrated in FIG. 22B or the state illustrated in FIG. 22D may be provided. That is, the state of FIG. 22B is a state in which the first switching valves 281 A and 28 IB are both closed, the second switching valve 282A is opened, and the second switching valve 282B is closed. The state of FIG. 22D is a state in which the first switching valves 281 A and 28 IB are both closed, the second switching valve 282A is closed, and the second switching valve 282B is opened.

[0110] When the forward circulation (A route) and the backward circulation (B route) are repeatedly performed in a switching manner, the states of the first switching valves 281 A and 28 IB and the second switching valves 282A and 282B are switched in the order of, for example, FIG. 22A FIG. 22B FIG. 22C FIG. 22D FIG. 22E FIG. 22D FIG. 22C FIG. 22B — FIG. 22A — FIG. 22B between the states of FIGS. 22B and 22D. According to this, it is possible to suppress the inside of the liquid discharge head 1 from being instantaneously brought to a positive pressure, and it is possible to prevent liquid leakage (dripping).

[0111] The state illustrated in FIG. 22F illustrates a state at the time of operation in non-circulation (unidirectional supply). In this case, the first switching valves 281 A and 28 IB are both opened, and the second switching valves 282A and 282B are both closed. In this case, liquid feeding to the first manifold 241 and the second manifold 251 is performed using only the first sub tank 211 and the first liquid feed pump 202, and the second sub tank 221 and the second liquid feed pump 203 are separated from the channel and do not contribute to theoperation. A method for actively using the second sub tank 221 and the second liquid feed pump 203 is also possible by additionally installing a channel and a switching valve that reverse the liquid feeding direction of the second liquid feed pump 203, but the description thereof is omitted here.

[0112] In the case of the present example, the first sub tank 211 is pressurized to a target pressure by the first liquid feed pump 202 based on the pressure detection information of both the first pressure sensor 242 and the second pressure sensor, but the set threshold value of the pressure value of each pressure sensor is appropriately set to an appropriate value, and is usually different from the threshold value in the case of forward circulation.

[0113] By using the liquid circulation mechanism (liquid supply apparatus) 200 described above, it is possible to circulate the liquid in the common channels 3a and 3b in the forward direction, circulate the liquid in the common channels 3 a and 3b in the backward direction, or only supply the liquid without circulation with respect to the liquid discharge head 1 of the first embodiment. In the liquid discharge head 1 of the first embodiment, at the time of initial liquid filling, sufficient filling property can also be obtained by a method for circulating liquid only in the forward direction. Here, in order to more effectively suppress generation of thickened liquid, foreign substances, and air bubbles difficult to discharge (air bubbles accumulated in comers or foreign substances, etc.) in the channel, it is preferable to perform liquid filling while switching the circulation direction of the liquid between the forward direction and the backward direction. The method for switching the circulation direction of liquid between the forward direction and the backward direction is also effective when liquid (for example, when the viscosity increases) in the sub tank is efficiently discharged.

[0114] On the other hand, from the viewpoint of management of the liquid discharge temperature (in a case of using multiple liquid discharge heads in a one-pass printer or the like, in a case of using the liquid by raising or lowering the temperature, or the like) and the viewpoint of productivity (in a case where a liquid discharge amount or a liquid transport amount is large, in a case where a nozzle refill speed is insufficient at a low temperature, or the like), it may be preferable not to circulate the liquid but to perform non-circulation (supply liquid only) at the time of driving the liquid discharge. According to the first embodiment, it is possible to perform liquid filling while switching the liquid circulation direction between the forward direction and the backward direction at the time of initial liquid filling, and to perform noncirculation (supply liquid only) without circulating the liquid at the time of driving the liquid discharge.Thus, a liquid filling method includes: filling a liquid into the liquid discharge head; causing the liquid to flow into the multiple individual channels from the first common channel facing the multiple openings of the multiple individual channels; and causing the liquid in themultiple individual channels to flow out from the second common channel, to fill the liquid in the liquid discharge head.The liquid filling method further includes: causing the liquid to flow into the multiple individual channels from the first common channel facing the multiple openings of the multiple individual channels; causing the liquid in the multiple individual channels to flow out from the second common channel, to fill the liquid in the liquid discharge head in a first filling direction as a first filling operation; and causing the liquid to flow into the multiple individual channels from the second common channel; and causing the liquid in the multiple individual channels to flow out from the first common channel, to fill the liquid in the liquid discharge head in a second filling direction opposite to the first filling direction as a second filling operation; and switching the first filling operation and the second filling operation.

[0115] Note that whether the filling property of liquid is good or bad is greatly affected by the shape and dimensions of each part of the channel, the state of the channel wall surface (roughness and unevenness, material and property of wall surface: hydrophilicity / water repellency, etc.), the type of liquid, the temperature and humidity, the static pressure state in the channel, and the like, and thus cannot be uniquely described. However, a simple experiment on the filling property of liquid is performed using the individual channel substrate 100 manufactured by performing DRIE processing on a silicon (Si) substrate, and the result of determining whether the filling property of liquid is good or bad (success rate) based on whether or not the liquid can be discharged from the predetermined nozzle 2 will be introduced.

[0116] In this simple experiment, a first comparative example illustrated in FIG. 23A, a second comparative example illustrated in FIG. 23B, and the first embodiment are compared. In each of the first comparative example and the second comparative example, only one common channel 3 is formed in a common channel substrate 120', and thus, all the individual channels 4 are coupled to a single common channel 3. Here, the first comparative example is an example of non-circulation in which liquid is only supplied from the supply liquid storage chamber 31 in the frame 140 to the common channel 3. On the other hand, the second comparative example is of a liquid circulation type that supplies liquid from the supply liquid storage chamber 31 in the frame 140 and discharges liquid to the discharge liquid storage chamber 35 in the frame 140 with respect to the common channel 3.

[0117] As a result of the simple experiment, the initial filling success rate is about 20% to 60% in the first comparative example, and the initial filling success rate is about 70% to 90% in the second comparative example. On the other hand, in the first embodiment, the result that the initial filling success rate is 98% or more (including the result of defective processing nozzle) is obtained. In addition, as illustrated in FIG. 24, it has been confirmed that, in at least one of the individual channels 4 and the common channels 3a and 3b, a portion where two mutually perpendicular planes such as a corner and a channel end of the channel are coupledis a curved portion or an obtuse portion that is rounded as much as possible, such as a configuration in which a part of the corner portions 3al and 3bl of the common channels 3a and 3b are rounded, and thus, a configuration without a right angle or an acute angle is implemented, which is effective in the air bubble discharge performance.

[0118] Second EmbodimentNext, another embodiment (hereinafter referred to as "second embodiment") of the liquid discharge head according to the present embodiment will be described.The liquid discharge head 1 according to the second embodiment has a configuration in which the fluid resistance members 38a and 38b are provided between the opening 4a of each individual channel 4 and the two common channels 3 a and 3b partitioned from each other by the common channel partition wall 120a. Other than this configuration, the second embodiment is substantially the same as the first embodiment described above (including each modification described above; the same applies hereinafter). Therefore, in the following description, overlapping description with the first embodiment described above will be omitted, and description different from the first embodiment described above will be made.

[0119] In the first embodiment described above, as described above, since the common channel 3 formed in the common channel substrate 120 is divided into the multiple common channels 3a and 3b, the number of surrounding individual channels 4 coupled to the same common channels 3a and 3b is reduced in each individual channel 4, and crosstalk that causes discharge failure of the nozzle 2 of each individual channel 4 is suppressed. Here, as the dimensions (opening area) of each opening 4a of the individual channel 4 communicating with each of the common channels 3a and 3b are larger, a pressure wave that causes crosstalk or an inertial flow that causes crosstalk easily escapes from the opening 4a of the individual channel 4 to each of the common channels 3 a and 3b. Therefore, when the dimensions (opening area) of each opening 4a of the individual channel 4 are large, crosstalk may not be sufficiently suppressed.

[0120] Also in the first embodiment described above, for example, by increasing the thickness dimension of the common channel partition wall 120a that divides the common channels 3 a and 3b and increasing the area where the common channel partition wall 120a closes the opening 4a of the individual channel 4, the dimensions (opening area) of the opening portion of the opening 4a communicating with each of the common channels 3 a and 3b can be reduced. Accordingly, it is possible to increase the channel resistance of the opening 4a to suppress the pressure wave or the inertial flow transmitted from the opening 4a of the individual channel 4 to each of the common channels 3 a and 3b. As a result, the combined vibration (the combined vibration due to the pressure wave or the inertial flow from each individual channel 4) generated in each of the common channels 3 a and 3b is reduced, and itis possible to sufficiently suppress crosstalk (acoustic crosstalk, fluid crosstalk) generated when the combined vibration is transmitted back to each individual channel 4.

[0121] However, when the thickness dimension of the common channel partition wall 120a is increased, the channel cross-sectional area of each of the common channels 3a and 3b is narrowed commensurately. Therefore, the channel resistance of each of the common channels 3 a and 3b is increased, and the flow of liquid in each of the common channels 3 a and 3b is deteriorated.

[0122] Therefore, in the second embodiment, the function of the fluid resistance is imparted to the opening portion of the opening 4a communicating with each of the common channels 3 a and 3b without deteriorating the flow of liquid in each of the common channels 3a and 3b, thereby obtaining the effect of sufficiently suppressing crosstalk.

[0123] FIG. 25 is a cross-sectional view schematically illustrating a liquid discharge head according to the second embodiment.The liquid discharge head 1 of the second embodiment includes the nozzle plate 110, the individual channel substrate 100, the common channel substrate 120, and the frame 140. Here, in the common channel substrate 120 of the second embodiment, on the individual channel substrate side of the same common channel substrate body 121 as the common channel substrate 120 of the first embodiment described above, the fluid resistance layer 123 constituting the fluid resistance members 38a and 38b that communicate the opening 4a of the individual channel 4 with the common channels 3a and 3b is provided.

[0124] According to the second embodiment, the fluid resistance layer 123 constituting the fluid resistance members 38a and 38b is provided separately from the common channel substrate body 121 constituting the multiple common channels 3a and 3b. Thus, by changing the dimensions of the fluid resistance members 38a and 38b of the fluid resistance layer 123 without changing the thickness dimension of the common channel partition wall 120a dividing the common channels 3a and 3b, it is possible to adjust and set the fluid resistance of the opening portion of the opening 4a communicating with each of the common channels 3a and 3b. Therefore, an appropriate fluid resistance can be set without deteriorating the flow of liquid in each of the common channels 3a and 3b, and an effect of sufficiently suppressing crosstalk can be obtained.

[0125] FIG. 26 is an explanatory diagram when an individual channel side is viewed from a common channel substrate side in the liquid discharge head.In the second embodiment, one common channel 3 a facing the opening 4a of the individual channel 4 is a supply common channel for supplying liquid to the individual channel 4, and the other common channel 3b facing the opening 4a of the individual channel 4 is a dischargecommon channel for discharging liquid from the individual channel 4. It is preferable that in such a configuration, the channel cross-sectional area of the fluid resistance member 38a corresponding to the common channel 3a is about 1 / 2 or less of the total area of the opening 4a of the individual channel 4. It is preferable that the channel cross-sectional area of the fluid resistance member 38b corresponding to the common channel 3b is larger than the channel cross-sectional area of the fluid resistance member 38a corresponding to the common channel 3a. The specific dimensions are appropriately set because the dimensions vary depending on the total area of the opening 4a of the individual channel 4, other channel dimensions, and the like. As an example, the opening dimension of the fluid resistance members 38a and 38b can be an opening dimension corresponding to a circle having a diameter of 40 [pm] or more and 60 [pm] or less.

[0126] The configurations of the fluid resistance members 38a and 38b according to the second embodiment are not limited thereto.For example, as illustrated in FIG. 27, the channel cross-sectional area of the fluid resistance member 38b corresponding to the common channel 3b may be smaller than the channel cross- sectional area of the fluid resistance member 38a corresponding to the common channel 3a.

[0127] The number of the fluid resistance members 38a and 38b communicating with the respective opening 4a of each individual channel 4 can also be appropriately set. For example, as illustrated in FIG. 28, two fluid resistance members 38a and three fluid resistance members 38b may communicate with the respective opening 4a of each individual channel 4. In the case of FIG. 28, as an example, the opening dimension of each of the fluid resistance members 38a and 38b can be an opening dimension corresponding to a circle having a diameter of about 20 [pm]. The opening shapes (hole shapes) of the fluid resistance members 38a and 38b may be any shapes such as round holes and rectangular holes.

[0128] In addition, the fluid resistance layer 123 according to the second embodiment can be easily formed on the common channel substrate body 121 constituting the multiple common channels 3a and 3b, and can be formed as the common channel substrate 120 of one component. As a result, effective measures can be taken without a large increase in manufacturing man-hours and cost.

[0129] Specifically, for example, the Si wafer can be processed by a semiconductor process and a MEMS process to manufacture an integrally formed product of the common channel substrate 120 including the common channel substrate body 121 and the fluid resistance layer 123. Further, for example, by bonding the common channel substrate body 121 and the fluid resistance layer 123, which are each made of a SUS plate or the like, by high-precision pressing, it is also possible to manufacture an integrally formed product of the common channel substrate 120 including the common channel substrate body 121 and the fluidresistance layer 123. In addition, it is also possible to manufacture an integrally formed product of the common channel substrate 120 including the common channel substrate body 121 and the fluid resistance layer 123 by a high-precision electroforming technique with an electroformed plate using photolithography similar to the semiconductor process and the MEMS process.

[0130] According to the second embodiment, as compared with the first embodiment described above, small grouping of groups of individual channels 4 (effect of reducing crosstalk and improvement of circularity), installation of a circulation configuration in each individual channel 4, and installation of fluid resistance in each individual channel 4 (suppress unnecessary pressure propagation from each individual channel 4 to each of the common channels 3 a and 3b) can be implemented by an integrated high-density channel component. Therefore, while maintaining high-density nozzle arrangements (channel arrangement, individual chamber arrangement), the number of components can be reduced and manufacture can be facilitated, and miniaturization, high density, and low cost can be achieved.

[0131] The shape and various dimensions of the common channel substrate 120 according to the second embodiment are determined by multiple parameters such as the channel length and the channel resistance of each unit such as the common channel substrate 120, and the individual channel substrate 100 and the nozzle plate 110 which are drive substrates (actuator substrates), the width (thickness) of various partition walls, and the rigidity of the housing, and further depend on the density (nozzle density) and various dimensions of the individual channel 4, the thickness, the size (diameter and area), and the rigidity of the nozzle plate 110, the nozzle dimensions (diameter and length), the generated force of the actuator (voltage, drive force), various characteristics of the liquid to be used (clay, surface tension, and the like), the drive method (drive waveform, voltage, etc.), and the like.

[0132] As described above, the common channel substrate 120 of the second embodiment can be manufactured from a Si wafer, a SUS plate, an electroformed plate, or the like, but it is preferable to use the same Si wafer as the drive substrates 100 and 110 from the viewpoints of accuracy, reproducibility, bondability to the drive substrates (the individual channel substrate 100 and the nozzle plate 110) (it is preferable that the thermal expansion coefficients thereof are as equal as possible), and cost. When a Si wafer is used, the thickness of the substrate is preferably in a range of about 50 [pm] or more and 2 [mm] or less, the thickness of the fluid resistance layer 123 is preferably in a range of about 0.1 [pm] or more and 1 [mm] or less, and therefore the thickness of the common channel substrate 120 is preferably in a range of 50 [pm] or more and 2 [mm] or less because of the limits due to the thickness and the manufacturing method of the Si wafer (in particular, wafer polishing, DRIE processing: deep etching processing, easy handling, etc.).

[0133] In consideration of the influence of various parameters, the thickness of the substrate is preferably in a range of 200 [pm] or more and 1 [mm] or less, and the thickness of the fluid resistance layer 123 is preferably in a range of about 0.1 [pm] or more and 400 [pm] or less. Therefore, the thickness of the common channel substrate 120 is more preferably in a range of 200 [pm] or more and 1 [mm] or less. Furthermore, the thickness of the substrate is preferably in a range of 400 [pm] or more and 800 [pm] or less, and the thickness of the fluid resistance layer 123 is preferably in a range of about 10 [pm] or more and 200 [pm] or less. Therefore, the thickness of the common channel substrate 120 is preferably in a range of 400 [pm] or more and 600 [pm] or less.

[0134] The number, size, and shape of the fluid resistance members 38a and 38b (holes) are appropriately determined in consideration of a trade-off relation between suppression of crosstalk and a refill supply rate (a rate at which liquid is filled (refilled) from the common channel 3a into the individual channel 4 before next discharge after liquid discharge). In particular, the slower the refill supply rate, the more difficult it is to achieve a high driving frequency.

[0135] The common channel 3 a, which is a supply common channel, needs to supply a desired amount (discharged liquid amount x drive frequency) of liquid to multiple channels (the nozzle 2, the individual channel 4) coupled thereto. In addition, the common channel 3b, which is the discharge common channel, needs to recover liquid. Therefore, these common channels 3a and 3b require sufficient channel conductance (sufficiently small channel resistance). The channel conductance (channel resistance) is generally determined by the channel cross-sectional area and the channel length.

[0136] The channel cross-sectional area is a product of the width (width viewed from the top view) and the height (substrate thickness) of the common channels 3a and 3b. The size of the channel width is limited by nozzle arrangements (channel arrangement and individual channel arrangement). Therefore, in order to ensure sufficient channel conductance, it is necessary to sufficiently increase (thicken) the heights (thicknesses) of the common channels 3a and 3b. However, on the other hand, from the viewpoint of workability, processing becomes difficult when the substrate is too thick, and thus the heights (thicknesses) of the common channels 3a and 3b are also limited. The thickness of the common channel substrate 120 of the second embodiment is determined in consideration of these. As described above, the channel width and the channel thickness are limited in terms of layout and processing, but in a case where sufficient channel conductance cannot be secured, for example, it is also effective to supply liquid from above to the common channel 3b which is the discharge common channel.

[0137] In addition, in a case where the channel conductance of the common channels 3 a and 3b is not sufficiently large, the common channel 3 a, which is the supply common channel, has a largerliquid flow rate than the common channel 3b, which is the discharge common channel.Therefore, the channel width of the common channel 3 a is preferably larger than the channel width of the common channel 3b. On the other hand, when sufficient channel conductance can be obtained, the channel width of the common channel 3a is not limited to this, and may be the same as the channel width of the common channel 3b, or the channel width of the common channel 3b, which is the discharge common channel, may be larger in order to improve the dischargeability.

[0138] In addition, the second embodiment is the same as the first embodiment described above, and for example, as in the first modification described above, both of the two common channels 3 a and 3b facing the respective opening 4a of the individual channel 4 may be configured as the supply common channels, or may be configured as other modifications, etc.

[0139] Next, an example of the liquid discharge apparatus according to the present embodiment is described with reference to FIGS. 29 and 30.FIG. 29 is a schematic explanatory diagram of a printing apparatus that is an inkjet recording apparatus which is an image forming apparatus as the liquid discharge apparatus according to the present embodiment.FIG. 30 is a plan explanatory diagram of an example of a head device of the printing apparatus of the present embodiment.

[0140] A printing apparatus 500, which is the liquid discharge apparatus, includes a feeder 501 that feeds a continuous medium 510, and a guide conveyor 503 that guides and conveys the continuous medium 510 fed from the feeder 501 to a printing unit 505. The printing apparatus 500 also includes the printing unit 505 that performs printing for discharging liquid onto the continuous medium 510 to form an image, a dryer 507 that dries the continuous medium 510, an ejector 509 that carries out the continuous medium 510, etc.

[0141] The continuous medium 510 is fed from a winding roller 511 of the feeder 501, guided and conveyed with rollers of the feeder 501, the guide conveyor 503, the dryer 507, and the ejector 509, and wound around a take-up roller 591 of the ejector 509. In the printing unit 505, the continuous medium 510 is conveyed opposite the head device 550 on a conveyance guide 559. The head device 550 discharges a liquid to form an image on the continuous medium 510.

[0142] In the printing apparatus 500 of the present embodiment, the head device 550 includes the two head modules 100A and 100B according to the present embodiment described above in the common base member 552.

[0143] The head module 100A includes head arrays 1A1, 1B1, 1A2, and 1B2. Each of the head arrays 1A1, 1B1, 1A2, and 1B2 includes multiple liquid discharge heads 1 arranged in a head array direction perpendicular to a conveyance direction of the head modules 100A and 100B. The head module 100B includes head arrays 1C1, 1D1, 1C2, and 1D2. Each of the head arrays 1C1, 1D1, 1C2, and 1D2 includes multiple liquid discharge heads 1 arranged in the head array direction perpendicular to the conveyance direction of the head modules 100A and 100B. The multiple liquid discharge heads 1 in each of the head arrays 1A1 and 1A2 of the head module 100A discharges liquid of the same desired color. Similarly, the head arrays IB 1 and 1B2 of the head module 100A are grouped as one set that discharge liquid of the same desired color. The head arrays 1C1 and 1C2 of the head module 100B are grouped as one set that discharge liquid of the same desired color. The head arrays 1D1 and 1D2 of the head module 100B are grouped as one set to discharge liquid of the same desired color.

[0144] Next, another example of a printing apparatus serving as a liquid discharge apparatus according to the present embodiment is described with reference to FIGS. 31 and 32. FIG. 31 is an explanatory plan view of a main part of the printing apparatus of the present example.FIG. 32 is an explanatory side view of a main part of the printing apparatus of the present example.

[0145] The printing apparatus 500 of the present example is a serial type apparatus, and a carriage 403 is reciprocally moved in a main-scanning direction by a main-scanning moving mechanism 493. The main- scanning moving mechanism 493 includes a guide 401, a main- scanning motor 405, a timing belt 408, and the like. The guide 401 is bridged between a left side plate 491 A and a right side plate 49 IB to moveably hold the carriage 403.The main- scanning motor 405 reciprocally moves the carriage 403 in the main- scanning direction via the timing belt 408 bridged between a drive pulley 406 and a driven pulley 407.

[0146] The carriage 403 mounts a liquid discharge device 440. The liquid discharge head 1 according to the present embodiment and a head tank 441 form the liquid discharge device 440 as a single unit. The liquid discharge head 1 discharges liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K).The liquid discharge head 1 includes a nozzle array including multiple nozzles arrayed in a sub-scanning direction. The sub-scanning direction is perpendicular to the main-scanning direction. The liquid discharge head 1 is mounted so that ink droplets are discharged downward. The liquid discharge head 1 is coupled to the liquid circulation device, and a liquid of a required color is circulated and supplied.

[0147] The printing apparatus 500 includes a conveyance mechanism 495 to convey a sheet 410. The conveyance mechanism 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 to a position facing the liquid discharge head 1. The conveyance belt 412 is an endless belt stretched between a conveyance roller 413 and a tension roller 414. Attraction of the sheet 410 to the conveyance belt 412 may be applied by electrostatic adsorption, air suction, or the like. The conveyance belt 412 rotates cyclically in the sub-scanning direction as the conveyance roller 413 is rotationally driven by the subscanning motor 416 via the timing belt 417 and the timing pulley 418.

[0148] At one side in the main- scanning direction of the carriage 403, a maintenance unit 420 to maintain the liquid discharge head 1 in good condition is disposed on a lateral side of the conveyance belt 412. The maintenance unit 420 includes, for example, a cap 421 to cap the nozzle surface of the liquid discharge head 1 and a wiper 422 to wipe the nozzle surface of the liquid discharge head 1. The main-scanning moving mechanism 493, the maintenance unit 420, and the conveyance mechanism 495 are mounted onto a housing including the side plates 491 A and 49 IB and a back plate 491C.

[0149] In the printing apparatus 500 thus configured, the sheet 410 is conveyed on and attracted to the conveyance belt 412 and is conveyed in the sub- scanning direction by a cyclic rotation of the conveyance belt 412. The liquid discharge head 1 is driven in response to image signals while the carriage 403 moves in the main- scanning direction to discharge a liquid to the sheet 410 stopped, thus forming an image on the sheet 410.

[0150] Next, another example of the liquid discharge device 440 according to according to an embodiment of the present invention is described with reference to FIG. 33.FIG. 33 is an explanatory plan view of a main part of the liquid discharge device of the present example.

[0151] The liquid discharge device 440 includes a housing, the main-scanning moving mechanism 493, the carriage 403, and the liquid discharge head 1 among components of the liquid discharge apparatus. The side plates 491 A and 49 IB and the back plate 491C constitute the housing.

[0152] Note that, in the liquid discharge device 440, the maintenance unit 420 described above may be mounted on the side plate 491B, for example.

[0153] Next, still another example of the liquid discharge device according to the present embodiment is described with reference to FIG. 34.FIG. 34 is an explanatory front view of the liquid discharge device of the present example.

[0154] The liquid discharge device 440 includes the liquid discharge head 1 to which a channel part 444 is attached, and a tube 456 coupled to the channel part 444.

[0155] The channel part 444 is disposed inside a cover 442. Instead of the channel part 444, the liquid discharge device 440 may include the head tank 441. A connector 443 electrically connected with the liquid discharge head 1 is provided on an upper part of the channel part 444.

[0156] 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 mPa- S under ordinary temperature and ordinary pressure or by heating or cooling. Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, or a surfactant, a biocompatible material, such as DNA, amino acid, protein, or calcium, or an edible material, such as a natural colorant. Such a solution, a suspension, or an emulsion can be used for, e.g., inkjet ink, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, or a material solution for three-dimensional fabrication.

[0157] The “liquid discharge device” is an assembly of parts relating to liquid discharge. The term “liquid discharge device” represents a structure including the liquid discharge head and a functional part(s) or unit(s) combined to the liquid discharge head to form a single unit. For example, the “liquid discharge device” includes a combination of the liquid discharge head with at least one of a head tank, a carriage, a supply unit, a maintenance unit, a main-scanning moving mechanism, and a liquid circulation device.

[0158] Examples of the “single unit” include a combination in which the liquid discharge head and one or more functional parts and units are secured to each other through, e.g., fastening, bonding, or engaging, and a combination in which one of the liquid discharge head and the functional parts and units is movably held by another. The liquid discharge head may be detachably attached to the functional part(s) or unit(s) each other.

[0159] For example, the liquid discharge head and the head tank may form the liquid discharge device as a single unit. Alternatively, the liquid discharge head and the head tank coupled 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 and the liquid discharge head of the liquid discharge device.

[0160] In another example, the liquid discharge head and the carriage may form the liquid discharge device as a single unit.

[0161] In still another example, the liquid discharge device includes the liquid discharge head movably held by a guide that forms part of a main-scanning moving mechanism, so that the liquid discharge head and the main-scanning moving mechanism form a single unit. The liquid discharge device may include the liquid discharge head, the carriage, and the main- scanning moving mechanism that form a single unit.

[0162] In still another example, a cap that forms a part of the maintenance unit may be secured to the carriage on which the liquid discharge head is mounted so that the liquid discharge head, the carriage, and the maintenance unit form a single unit to form the liquid discharge device.

[0163] Further, in still another example, the liquid discharge device includes tubes coupled to the head tank or the liquid discharge head on which a channel member is mounted so that the liquid discharge head and the supply unit form a single unit. A liquid in a liquid storage source is supplied to the liquid discharge head through this tube.

[0164] The main- scanning moving mechanism may be a guide only. The supply unit may be a tube(s) only or a loading unit only.

[0165] 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.

[0166] The term “liquid discharge apparatus” used herein also represents an apparatus including the liquid discharge head, the liquid discharge device, the head module, the head device, and 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 a liquid to a material to which liquid can adhere or an apparatus to discharge liquid toward gas or into liquid.

[0167] 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.

[0168] 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 dischargea fabrication liquid to a powder layer in which powder material is formed in layers to form a three-dimensional fabrication object.

[0169] 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 meaningless images, such as meaningless patterns, or fabricate three-dimensional images.

[0170] The above-described term “material onto which liquid can adhere” 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 adhere” 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 adhere” includes any material on which liquid can adhere, unless particularly limited.

[0171] Examples of the “material onto which liquid can adhere” include any materials on which liquid can adhere even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic.

[0172] The “liquid discharge apparatus” may be an apparatus to relatively move the liquid discharge head and a material on which liquid can adhere. However, the liquid discharge apparatus is not limited to such an apparatus. For example, the liquid discharge apparatus may be a serial type apparatus that moves the liquid discharge head or a line type apparatus that does not move the liquid discharge head.

[0173] Examples of the “liquid discharge apparatus” further include a treatment liquid coating apparatus to discharge the treatment liquid to a sheet to coat the treatment liquid on 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. Further, there is an injection granulation apparatus for spraying a composition liquid in which raw materials are dispersed in a solution through a nozzle to granulate fine particles of the raw material.

[0174] The terms “image formation”, “recording”, “printing”, “image printing”, and “fabricating” used herein may be used synonymously with each other.

[0175] The above-described embodiments are limited examples, and the present disclosure includes, for example, the following aspects having advantageous effects.Aspect 1According to Aspect 1, the liquid discharge head 1 includes: multiple nozzles 2 that discharge liquid (for example, an ink); multiple individual channels 4 that respectively communicate with the multiple nozzles; multiple actuators (for example, the piezoelectric element 5, the heater element 5') that are respectively provided for the multiple individual channels; and the common channel 3 that faces each opening 4a of the multiple individual channels located on a side facing a nozzle forming wall (for example, the nozzle plate 110) of the multiple individual channels, the actuators being driven to discharge the liquid in the individual channels from the nozzles, the common channel including multiple common channels 3a and 3b partitioned from each other by a partition wall (for example, the common channel partition wall 120a), and each opening of the multiple individual channels facing two or more of the common channels, which are different from each other, among the multiple common channels.In a conventional liquid discharge head in which a common channel is provided in a manner of facing an opening of each individual channel located on a side facing a nozzle forming wall with respect to multiple individual channels respectively communicating with multiple nozzles, when liquid is filled into the liquid discharge head at an initial stage, air bubbles may remain in the individual channels, particularly, at corners of the individual channels (connection portions between nozzle forming walls and side walls of the individual channels). When air bubbles are generated in the individual channels, the liquid in the individual channels cannot be appropriately discharged from the nozzles by driving the actuators, and a liquid discharge failure may occur.In the conventional liquid discharge head, one common channel faces the entire opening of each individual channel. Therefore, liquid flows in and out substantially uniformly with respect to the entire opening of each individual channel. Therefore, the movement of the liquid in the individual channels is small, and for example, when liquid is supplied from the opening of the individual channel into the individual channel and the individual channel is filled with the liquid at the time of liquid filling to the liquid discharge head, air bubbles are likely to be generated at the corners, etc. of the individual channel. In addition, since the movement of the liquid in the individual channels is small even during the operation of the liquid discharge head, air bubbles at the comers, etc. of the individual channels continue to stay at the corners, and as a result, discharge failure occurs.In the present aspect, two or more common channels different from each other among the multiple common channels partitioned from each other by the partition wall face each opening of the multiple individual channels. According to this, there are two or more portions through which liquid flows in and out of the opening of the individual channel, and thus, the inflow and outflow (flow) of liquid to and from the opening of the individual channel are likely to be asymmetric at the two or more portions. Therefore, as compared with the conventional configuration in which the entire opening of the individual channel faces one common channel and liquid flows in and out substantially uniformly with respect tothe entire opening of the individual channel, the movement of the liquid in the individual channel is likely to be easily generated. As a result, the air bubbles at the corners of the individual channels are likely to move from the comers of the individual channels, and the air bubbles are discharged from the individual channels at the time of liquid filling or during operation of the liquid discharge head, and occurrence of discharge failure is suppressed.

[0176] Aspect 2According to Aspect 2, in the liquid discharge head 1 of Aspect 1, the two or more common channels facing each opening of the multiple individual channels are supply common channels that supply liquid to the individual channels.According to this, when the consumption amount (discharge amount) of liquid is large, stable liquid supply to each individual channel can also be implemented.

[0177] Aspect 3According to Aspect 3, in the liquid discharge head 1 of Aspect 1, a part of the two or more common channels facing each opening of the multiple individual channels are supply common channels that supply liquid to the individual channels, and another part of the two or more common channels are discharge common channels that discharge liquid from the individual channels.According to this, with respect to the opening of the individual channel, it is possible to create a flow for allowing liquid to flow from the supply common channels into the opening and a flow for allowing liquid to flow out from the opening to the discharge common channels, and it is possible to exchange the liquid in the individual channel. Therefore, the movement of the liquid in the individual channel can be made more active, air bubbles in the individual channel can be easily moved and discharged from the individual channel, and the occurrence of discharge failure can be further suppressed.

[0178] Aspect 4According to Aspect 4, in the liquid discharge head 1 of any of Aspects 1 to 3, the common channel substrate 120 constituting the multiple common channels is configured as a substrate different from the individual channel substrate 100 constituting the multiple individual channels.According to this, it is possible to manufacture the common channel substrate and the individual channel substrate by processing each with high precision.

[0179] Aspect 5According to Aspect 5, in the liquid discharge head 1 of Aspect 4, the common channel substrate 120 includes the fluid resistance layer 123 constituting the fluid resistance members 38a and 38b that communicate the openings of the individual channels with the common channels.According to the present aspect, the fluid resistance layer constituting the fluid resistance members is provided separately from the substrate body of the common channel substrate constituting the multiple common channels. Thus, by changing the dimensions of the fluid resistance members of the fluid resistance layer without changing the thickness dimension of the common channel partition wall dividing the common channels, it is possible to adjust and set the fluid resistance of the opening portion of the opening of the individual channel communicating with each of the common channels. Therefore, an appropriate fluid resistance can be set without deteriorating the flow of liquid in each of the common channels, and an effect of sufficiently suppressing crosstalk can be obtained.

[0180] Aspect 6According to Aspect 6, in the liquid discharge head 1 of any of Aspects 1 to 3, the openings of the individual channels and the common channels communicate with each other via a fluid resistance member.According to the present aspect, it is possible to obtain an effect of sufficiently suppressing crosstalk by adjusting and setting the fluid resistance of the opening portion of the opening of the individual channel communicating with each common channel.

[0181] Aspect 7According to Aspect 7, in the liquid discharge head 1 of any of Aspects 1 to 6, cross-sectional areas of respective channels communicating the openings of the individual channels respectively with each of the two or more common channels are different from each other. According to this, as compared with the configuration in which cross-sectional areas of respective channels communicating the opening of the individual channel with each of the two or more common channels are the same as each other, there is a difference in the inflow and outflow of liquid with respect to the individual channel between the respective channels, and the movement of the liquid in the individual channel becomes active.In particular, by making the channel cross-sectional area corresponding to the discharge common channel larger than the channel cross-sectional area corresponding to the supply common channel, the inflow and outflow of liquid with respect to the individual channel can be made smooth.

[0182] Aspect 8According to Aspect 8, in the liquid discharge head 1 of Aspect 4 or 5, the common channel substrate is formed of any of a Si wafer, a SUS plate, and an electroformed plate.According to this, high-precision processing becomes possible, and a high-precision common channel substrate can be manufactured.

[0183] Aspect 9According to Aspect 9, in the liquid discharge head 1 of Aspect 4, 5 or 8, a thickness of the common channel substrate is in a range of 0.05 [mm] or more and 2 [mm] or less.According to this, it is possible to maintain an appropriate flow of liquid by securing an appropriate channel cross-sectional area while securing a rigidity necessary for the common channel substrate.

[0184] Aspect 10According to Aspect 10, in the liquid discharge head 1 of any of Aspects 1 to 9, the damper member 130 is provided on a side of the multiple common channels facing the openings of the multiple individual channels.According to this, the crosstalk generated at the time of simultaneous driving the multiple nozzles can be reduced by the function of the damper member.

[0185] Aspect 11According to Aspect 11, in the liquid discharge head 1 of Aspect 10, the damper member includes a film-shaped member disposed across the multiple common channels, and a peripheral edge of the film-shaped member is secured.According to this, it is possible to increase the compliance and increase the damper function of the damper member.

[0186] Aspect 12According to Aspect 12, in the liquid discharge head 1 of any of Aspects 1 to 11, a portion where two planes perpendicular to each other are coupled is an obtuse portion or a curved portion in at least one of the individual channels and the common channels.According to this, it is possible to suppress generation and stagnation of puddle of air bubbles in the channel.

[0187] Aspect 13According to Aspect 13, in the liquid discharge head 1 of any of Aspects 1 to 12, the actuator is disposed on the nozzle forming wall, in an interior of the nozzle forming wall, or in the vicinity of the nozzle forming wall.According to this, it is possible to easily implement a configuration in which the common channels face the openings of the multiple individual channels located on the side facing the nozzle forming wall.

[0188] Aspect 14According to Aspect 14, in the liquid discharge head 1 of Aspect 13, the actuator is an electromechanical transducer (for example, the piezoelectric element 5) that displaces the nozzle forming wall.According to this, a so-called nozzle plate vibration type liquid discharge head can be provided.

[0189] Aspect 15According to Aspect 15, in the liquid discharge head 1 of Aspect 13, the actuator is the heater element 5' that generates bubbles in the liquid in the individual channels.According to this, it is possible to provide a liquid discharge head of a type that discharges liquid by generating bubbles in the liquid in the individual channels 4.

[0190] Aspect 16According to Aspect 16, a liquid discharge apparatus includes the liquid discharge head of any of Aspects 1 to 15.According to this, it is possible to provide a liquid discharge apparatus that suppresses discharge failure due to air bubbles generated in the individual channels.

[0191] Aspect 17According to Aspect 17, a liquid filling method for filling liquid in the liquid discharge head of any of Aspects 1 to 15 includes filling liquid in the liquid discharge head by causing liquid to flow into the individual channels from a part of the two or more common channels facing the openings of the multiple individual channels and causing the liquid in the individual channels to flow out from another part of the two or more common channels.According to this, it is possible to appropriately fill the liquid discharge head with liquid without generating air bubbles or the like in the channels in the liquid discharge head.

[0192] Aspect 18According to Aspect 18, in the liquid filling method of Aspect 17, a first filling step (for example, forward circulation) of causing liquid to flow into the individual channels from the part of the two or more common channels facing the openings of the multiple individual channels and causing the liquid in the individual channels to flow out from the another part of the two or more common channels and a second filling step (for example, backward circulation) of causing liquid to flow into the individual channels from the another part of the two or more common channels and causing the liquid in the individual channels to flow out from the part of the two or more common channels are performed in a switching manner. According to this, liquid can be filled in the liquid discharge head with a better filling property.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.This patent application is based on and claims priority to Japanese Patent Application No. 2023-040599, filed on March 15, 2023, in the Japan Patent Office, and Japanese Patent Application No. 2023-207135, filed on December 7, 2023, in the Japan Patent Office, the entire disclosure of which are hereby incorporated by reference herein.[Reference Signs List]

[0193] 1 : Liquid discharge head2: Nozzle3: Common channel3a: Supply common channel3b: Discharge common channel3c, 3 cl, 3 c2: Channel inlet3d, 3dl, 3d2: Channel outlet3e, 3f: Communication channel4: Individual channel4a: Opening5: Piezoelectric element5': Heater element31: Supply liquid storage chamber35: Discharge liquid storage chamber38a, 38b: Fluid resistance member100: Individual channel substrate103: Vibration film110: Nozzle plate120: Common channel substrate120a: Common channel partition wall120d: Partition wall121: Common channel substrate body122: Upper wall123: Fluid resistance layer130: Damper member131: Air chamber132: Adhesive140: Frame200: Liquid circulation device201: Main tank202: First liquid feed pump203: Second liquid feed pump204: Main liquid feed pump211: First sub tank221: Second sub tank231 : Main sub tank241: First manifold242: First pressure sensor251: Second manifold252: Second pressure sensor261: First pressurizing and depressurizing damper262: Second pressurizing and depressurizing damper271: Foreign substance removing filter272: Deaerating device281 A, 28 IB: First switching valve282A, 282B: Second switching valve[Citation List][Patent Literature]

[0194] [PTL 1]Japanese Unexamined Patent Application Publication No. 2021-041569

Claims

[CLAIMS]

1. A liquid discharge head comprising: a nozzle forming wall having multiple nozzles from each of which a liquid is dischargeable in a discharge direction; multiple individual channels respectively having: multiple first faces each formed by the nozzle forming wall and respectively communicating with the multiple nozzles; and multiple second faces respectively opposite to the multiple first faces in the discharge direction, the multiple second faces respectively having multiple openings; multiple actuators driven to discharge the liquid in the multiple individual channels from the multiple nozzles, respectively; a first common channel including first multiple common-branch channels partitioned from each other by a first partition wall; and a second common channel including second multiple common-branch channels partitioned from each other by a second partition wall, wherein one of the multiple openings of the multiple second faces of the multiple individual channels faces one of the first multiple common-branch channels and one of the second multiple common-branch channels.

2. The liquid discharge head according to claim 1, wherein each of the first multiple common-branch channels and the second multiple commonbranch channels supplies the liquid to the multiple individual channels from the multiple openings.

3. The liquid discharge head according to claim 1, wherein the first multiple common-branch channels supply the liquid to the multiple individual channels, and the second multiple common-branch channels discharge the liquid from the multiple individual channels.

4. The liquid discharge head according to any one of claims 1 to 3, further comprising: a common channel substrate having the first common channel and the second common channel; and an individual channel substrate different from the common channel substrate, the individual channel substrate having the multiple individual channels.

5. The liquid discharge head according to claim 4, further comprising a fluid resistance layer between the common channel substrate and the individual channel substrate,wherein the fluid resistance layer is a fluid resistance member through which the first common channel and the second common channel communicating with the multiple openings of the multiple individual channels.

6. The liquid discharge head according to any one of claims 1 to 3, further comprising a fluid resistance member through which the multiple openings of the multiple individual channels communicate with the first common channel and the second common channel.

7. The liquid discharge head according to any one of claims 1 to 3, wherein each of the first partition wall and the second partition wall are: across at least one of the multiple openings; and shifted from a center of the at least one of the multiple openings.

8. The liquid discharge head according to any one of claims 1 to 3, further comprising: a common channel substrate having the first common channel and the second common channel; and a damper member on a first face of the common channel substrate opposite to a second face of the common channel substrate facing the multiple openings of the multiple individual channels.

9. The liquid discharge head according to claim 8, wherein the damper member includes a film member covering the first common channel and the second common channel, and the film member has a peripheral edge secured to the common channel substrate.

10. The liquid discharge head according to any one of claims 1 to 3, wherein a portion, where two planes perpendicular to each other are coupled in at least one of the multiple individual channels, the first common channel, or the second common channel, has an obtuse portion or a curved portion.

11. The liquid discharge head according to any one of claims 1 to 3, wherein each of the multiple actuators is disposed on at least one of: the nozzle forming wall; an interior of the nozzle forming wall; or a portion in vicinity of the nozzle forming wall.

12. The liquid discharge head according to claim 11, wherein each of the multiple actuators includes a heater element generatable bubbles in the liquid in each of the multiple individual channels.

13. A liquid discharge apparatus comprising the liquid discharge head according to any one of claims 1 to 3.

14. A liquid filling method comprising: filling a liquid into the liquid discharge head according to any one of claims 1 to 3; causing the liquid to flow into the multiple individual channels from the first common channel facing the multiple openings of the multiple individual channels; and causing the liquid in the multiple individual channels to flow out from the second common channel, to fill the liquid in the liquid discharge head.

15. The liquid filling method according to claim 14, further comprising: causing the liquid to flow into the multiple individual channels from the first common channel facing the multiple openings of the multiple individual channels; causing the liquid in the multiple individual channels to flow out from the second common channel, to fill the liquid in the liquid discharge head in a first filling direction as a first filling operation; and causing the liquid to flow into the multiple individual channels from the second common channel; and causing the liquid in the multiple individual channels to flow out from the first common channel, to fill the liquid in the liquid discharge head in a second filling direction opposite to the first filling direction as a second filling operation; and switching the first filling operation and the second filling operation.

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