JP2015104911A - Droplet discharge head and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain satisfactory bubble dischargeability, and excellent discharging performance by restricting cross talk at an end part.SOLUTION: A droplet discharge head 1 includes: a plurality of pressurizing liquid chambers 12 communicating with a plurality of nozzles 11; a common liquid chamber 14 disposed so as to extend above the pressurizing liquid chambers in a gravity direction and in an alignment direction of the pressurizing liquid chambers; and a diaphragm 30 and a piezoelectric element 50 forming one wall surface of the pressurizing liquid chambers. In the droplet discharge head 1, the common liquid chamber has a Z narrowing section 76 where an inner wall surface on an opposite side of the pressurizing liquid chambers toward an end part in the alignment direction of the pressurizing liquid chambers, that is a downstream side in a flowing direction of ink, is brought close to a pressurizing liquid chamber side, and by using a diaphragm damper 62 at an end part extending to an outer side beyond the pressurizing liquid chambers in the alignment direction, a wall surface of the pressurizing liquid chamber side of the common liquid chamber is made deformable, and a damper mechanism is provided on the pressurizing liquid chamber side of the end part of the common liquid chamber.

Description

  The present invention relates to a droplet discharge head that discharges droplets from a nozzle, and an image forming apparatus that employs the droplet discharge head.

  In general, a printer, a fax machine, a copier, a plotter, or an image forming apparatus that combines a plurality of these functions includes, for example, a droplet ejection head that ejects ink droplets (hereinafter referred to as ink droplets). There is an ink jet recording apparatus. In an ink jet recording apparatus, an image is formed by adhering ink droplets to a sheet by a droplet discharge head while conveying a medium. The medium here is also referred to as “paper”, but the material is not limited, and a recording medium, a recording medium, a transfer material, a recording paper, and the like are also used synonymously. The image forming apparatus means an apparatus for forming an image by ejecting liquid droplets on a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramic. The image formation is not only giving an image having a meaning such as a character or a figure to the medium but also giving an image having no meaning such as a pattern to the medium (simply ejecting a droplet). Also means. The ink is not limited to so-called ink, and is not particularly limited as long as it becomes a droplet when ejected. For example, the ink is a generic term for liquids including DNA samples, resists, pattern materials, and the like. Used as

  The droplet discharge head generates pressure fluctuations in a plurality of pressurized liquid chambers (also referred to as pressure chambers, discharge chambers, individual liquid chambers, ink chambers, etc.) that communicate with a plurality of nozzles. A pressure generating means, a common liquid chamber for supplying liquid in communication with each pressurized liquid chamber, and the like are provided. By supplying ink from the ink cartridge of the ink jet recording apparatus to each pressurized liquid chamber via the common liquid chamber of the droplet discharge head, and driving the pressure generating means to generate pressure fluctuations in the pressurized liquid chamber, the nozzle Ejected as ink droplets. As the droplet discharge head, an ink-on-demand type is mainly used in which the pressure generating means is driven only when necessary for recording, and the pressure in the pressurized liquid chamber is increased to discharge the ink droplet from the nozzle. is there.

  The droplet discharge head is roughly classified into several types depending on the type of pressure generating means for generating pressure fluctuations in each pressurized liquid chamber. For example, a heating element is arranged inside the pressurized liquid chamber, and energizing the heating element to heat the heating element, thereby generating bubbles in the ink in the pressurized liquid chamber, and the pressure in the pressurized liquid chamber is increased by the pressure of the bubbles. A thermal method in which the pressure of the ink is boosted to eject droplets is widely known. In addition, one wall surface of the pressurized liquid chamber is constituted by a vibration plate, a piezoelectric element is disposed on the vibration plate, a driving voltage is applied to the piezoelectric element, and the piezoelectric element is deformed to deform the vibration plate. Thus, a piezo method in which the pressure in the pressurized liquid chamber is increased to eject droplets is widely known. In addition to this, one wall surface of the pressurized liquid chamber is constituted by a diaphragm, an electrode is arranged outside the pressurized liquid chamber so as to face the diaphragm, and an electrostatic force is generated by forming an electric field between the electrodes. There is also an electrostatic method in which the diaphragm is deformed, and thereby the pressure of the ink in the pressurized liquid chamber is increased to eject droplets.

  In the droplet discharge head, pressure fluctuations generated in the pressurized liquid chamber propagate to the common liquid chamber communicating with each other, causing mutual interference (crosstalk) that affects the ink in the adjacent pressurized liquid chamber. The state may become unstable. In order to suppress such crosstalk, it is known to provide a damper mechanism in the common liquid chamber to alleviate the propagated pressure fluctuation.

  Also, in the liquid droplet ejection head, bubbles are mixed into the ink when filling the ink from the ink cartridge into the common liquid chamber, and even if the pressure is increased by driving the pressure generating means, the presence of the mixed bubbles causes a predetermined It may cause discharge failure without becoming pressure. In order to suppress such ejection failure, it is indispensable to discharge bubbles mixed in the ink in the droplet ejection head. Patent Document 1 describes an ink jet recording apparatus including a suction unit that discharges bubbles by sucking ink in a droplet discharge head from a nozzle and sucking the bubbles together with the ink. In addition, this droplet discharge head is provided with a damper mechanism above the common liquid chamber to suppress crosstalk in the common liquid chamber.

  Patent Document 2 discloses a droplet having a shape in which the inner wall surface of the common liquid chamber opposite to the pressurized liquid chamber approaches the pressurized liquid chamber side toward the end of the common liquid chamber in the direction of ink flow. An ejection head is described.

  The droplet discharge head of Patent Document 1 is provided so that the common liquid chamber extends in the direction of gravity in the direction of gravity above the pressure liquid chamber and extends from the center in the arrangement direction to the common liquid chamber. The supplied ink is caused to flow toward the end in the arrangement direction in the common liquid chamber and is supplied to the pressurized liquid chamber below. The ink supplied to the pressurizing liquid chamber is ejected as ink droplets downward from the nozzle provided on the lower surface of the pressurizing liquid chamber. Thus, discharging ink droplets from the nozzles downward in the direction of gravity is preferable in order to ensure that the discharged ink droplets land on the paper.

  In this droplet discharge head, the ink is sucked from the nozzle downward in the gravity direction by the suction means to discharge bubbles lighter than the ink, and in order to obtain good bubble discharge performance, the bubbles are directed downward. It is effective to secure a flow rate that can be washed away. In this droplet discharge head, the width of the flow path becomes narrower toward the end in the arrangement direction (hereinafter simply referred to as the end) on the downstream side in the ink flow direction in the common liquid chamber, and the section perpendicular to the arrangement direction is cut. The area decreases toward the edge. Thereby, it is easy to secure a flow rate at which the bubbles pushed out to the end of the common liquid chamber where the flow rate decreases at the downstream side of the ink flow direction can be secured, and the bubble discharge property is improved. However, even in the common liquid chamber having a shape in which the width of the flow path is narrowed toward the end, the bubbles are pushed out to the end of the common liquid chamber and stay in the upper portion, so that a good bubble discharge property is obtained. In some cases, it could not be obtained.

  In the liquid droplet ejection head of Patent Document 2, the cross-sectional area perpendicular to the arrangement direction is directed toward the end by bringing the inner wall surface opposite to the pressurization liquid chamber toward the end toward the pressurization liquid chamber. Thus, the bubbles pushed out at the end are made to flow easily toward the pressurized liquid chamber without staying in the upper part while increasing the flow rate. Thereby, bubble discharge property can be improved.

  However, if the inner wall surface opposite to the pressurized liquid chamber is brought closer to the pressurized liquid chamber side at the end of the common liquid chamber, reflection of pressure fluctuations propagated from the pressurized liquid chamber to the common liquid chamber becomes larger. As a result, crosstalk at the end increases, and the discharge state becomes unstable at the end.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and a purpose of the present invention is to provide a liquid droplet discharge head that can obtain good bubble discharge performance and suppress crosstalk at the end portion to obtain good discharge performance. And an image forming apparatus.

In order to achieve the above-mentioned object, the invention of claim 1 includes a plurality of pressurized liquid chambers communicating with a plurality of nozzles, and extending in an arrangement direction of the pressurized liquid chambers above the pressurized liquid chamber in a direction of gravity. A common liquid chamber that communicates with the pressurized liquid chamber and supplies the liquid, and pressure generating means for generating a pressure fluctuation in the pressurized liquid chamber so as to discharge droplets from the nozzle. In the liquid drop ejection head,
The common liquid chamber is opposite to the pressurized liquid chamber so that the cross-sectional area perpendicular to the arrangement direction decreases as it goes to the end in the arrangement direction, which is downstream in the flow direction of the liquid flowing in the common liquid chamber. The inner wall surface on the side is formed so as to approach the pressurized liquid chamber side, and the wall surface on the pressurized liquid chamber side of the common liquid chamber portion that extends outward from the pressurized liquid chamber in the arrangement direction Is configured to be deformable.

  According to the present invention, there is an excellent effect that it is possible to obtain good discharge performance by obtaining good bubble discharge properties and suppressing crosstalk at the end.

1 is a perspective view illustrating a configuration of an ink jet recording apparatus according to an embodiment. FIG. 3 is a side view of a mechanism unit of the ink jet recording apparatus according to the embodiment. It is a cross-sectional explanatory drawing of a part of the droplet discharge head of this embodiment, (a) is a cross-sectional explanatory diagram in the width direction, (b) shows a cross-sectional explanatory diagram in the nozzle row direction. FIG. 6 is a process cross-sectional view illustrating a manufacturing process of an ink droplet ejection mechanism portion of the droplet ejection head according to the present embodiment. Process sectional drawing which shows the process after FIG. 4 of the manufacturing process of the ink droplet discharge mechanism part of the droplet discharge head of this embodiment. The disassembled perspective view of the molded object which comprises the other part of the droplet discharge head of this embodiment. Sectional drawing of the molded object which comprises the other part of the droplet discharge head of this embodiment. FIG. 6 is a cross-sectional explanatory view in the nozzle row direction schematically showing the ink flow path of the droplet discharge head of the present embodiment. FIG. 3 is a schematic view of a pressurized liquid chamber of the droplet discharge head of Example 1 as viewed from the diaphragm side. FIG. 6 is a schematic view of a pressurized liquid chamber of a droplet discharge head of Example 2 as viewed from the diaphragm side. FIG. 6 is a schematic view of a pressurized liquid chamber of a droplet discharge head according to a third embodiment when viewed from the diaphragm side. FIG. 6 is a schematic view of a pressurized liquid chamber of a droplet discharge head of Example 4 as viewed from the diaphragm side. FIG. 4 is an explanatory diagram of an example of a malfunction in a discharge state of a droplet discharge head including a common liquid chamber provided with a narrowed portion at an end.

  Hereinafter, an ink jet recording apparatus as an embodiment of an image forming apparatus to which the present invention can be applied will be described. FIG. 1 is a perspective view showing a configuration of an ink jet recording apparatus according to the present embodiment, and FIG. 2 is a side view of a mechanism portion of the ink jet recording apparatus according to the present embodiment.

  The ink jet recording apparatus 100 includes a print mechanism 103 that includes a carriage 101, a droplet discharge head 1 mounted on the carriage 101, an ink cartridge 102 that supplies ink to the droplet discharge head 1, and the like inside the main body. Have. The carriage 101 is a member that can move in the main scanning direction that is orthogonal to the transport direction of the paper S within the main body of the inkjet recording apparatus 100.

  As shown in FIG. 2, a paper feed cassette (or a paper feed tray) 104 capable of stacking a large number of recording papers from the front side is detachably attached to the lower part of the apparatus main body. Further, it has a manual feed tray 105 that is opened to manually feed the recording paper, and takes in the recording paper fed from the paper feed cassette 104 or the manual feed tray 105. Then, after a required image is recorded by the printing mechanism unit 103, the image is discharged to a discharge tray 106 mounted on the rear side.

  The printing mechanism 103 holds the carriage 101 slidably in the main scanning direction with a main guide rod 107 and a sub guide rod 108 which are guide members horizontally mounted on left and right side plates (not shown). The carriage 101 has a plurality of ink ejection openings (described later, “Electric droplet ejection head 1 for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk)”). Nozzles 11 ") are arranged in a direction perpendicular to the main scanning direction. Furthermore, the droplet discharge head 1 is mounted on the carriage 101 with the ink droplet discharge direction facing downward. In addition, each ink cartridge 102 for supplying ink of each color to the droplet discharge head 1 is replaceably mounted on the carriage 101.

  The ink cartridge 102 is provided with an air opening communicating with the atmosphere above, and a supply opening for supplying ink to the droplet discharge head 1 below, and has a porous body filled with ink inside. The ink supplied to the droplet discharge head 1 is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the droplet discharge head is used for each color as the droplet discharge head 1, one droplet discharge head having nozzles for discharging ink droplets of each color may be used.

  Here, the carriage 101 is slidably fitted to the main guide rod 107 on the rear side (downstream side in the paper conveyance direction) and slidable on the front guide rod 108 on the front side (upstream side in the paper conveyance direction). It is placed. In order to move and scan the carriage 101 in the main scanning direction, a timing belt 112 is stretched between a driving pulley 110 and a driven pulley 111 that are rotationally driven by a main scanning motor 109a. The timing belt 112 is fixed to the carriage 101, and the carriage 101 is reciprocally scanned by forward and reverse rotation of the main scanning motor 109a.

  On the other hand, the recording paper set in the paper feed cassette 104 is conveyed to the lower side of the droplet discharge head 1. For this purpose, a paper feed roller 113 and a friction pad 114 for separating and feeding the recording paper from the paper feed cassette 104 and a guide member 115 for guiding the recording paper are provided. Furthermore, a conveyance roller 116 that reverses and conveys the fed recording paper, a conveyance roller 117 that is pressed against the peripheral surface of the conveyance roller 116, and a leading end roller 118 that defines a feeding angle of the recording paper from the conveyance roller 116. have. The conveyance roller 116 is rotationally driven via a gear train by the sub-scanning motor 109b.

  In addition, a printing receiving member 119 that is a paper guide member is provided to guide the recording paper fed from the transport roller 116 corresponding to the movement range of the carriage 101 in the main scanning direction on the lower side of the droplet discharge head 1. Yes. On the downstream side of the printing receiving member 119 in the paper conveyance direction, a conveyance roller 120 and a spur 121 that are rotationally driven to send the recording paper in the paper discharge direction are provided. Further, a discharge roller 123 and a spur 124 for feeding the recording paper to the discharge tray 106, and guide members 125 and 126 for forming a discharge path are provided.

  When recording with the inkjet recording apparatus 100, the droplet discharge head 1 is driven according to the image signal while moving the carriage 101, thereby discharging ink onto the stopped recording paper to record one line, Thereafter, after the recording paper is conveyed by a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the recording paper reaches the recording area, the recording operation is terminated and the recording paper is discharged.

  A recovery device 127 for recovering the ejection failure of the droplet ejection head 1 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 101. Each of the recovery devices 127 includes a cap unit, a suction unit, and a wiping unit (not shown). During printing standby, the carriage 101 is moved to the recovery device 127 side, and the droplet discharge head 1 is capped by the capping unit to keep the discharge port portion in a wet state, thereby preventing discharge failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  Further, when a discharge failure occurs, the discharge port (nozzle) of the droplet discharge head 1 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port through the tube with a suction unit. Subsequently, ink, dust or the like adhering to the discharge port surface is removed by wiping the discharge port surface with a wiping means, and the discharge failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  Next, the droplet discharge head 1 of this embodiment will be described. FIG. 3 is a cross-sectional explanatory view of a part of the droplet discharge head 1 of the present embodiment. FIG. 3A is a cross-sectional explanatory diagram in the width direction of the droplet discharge head. For convenience, only the ink droplet discharge mechanism corresponding to one of the four colors Y, M, C, and K is shown. . FIG. 3B is a cross-sectional explanatory view in the direction of arrangement of the pressurized liquid chambers of the droplet discharge head 1 (hereinafter referred to as the nozzle row direction). For convenience, the liquid corresponding to the two pressurized liquid chambers 12 is shown. Only the droplet discharge mechanism is shown. This droplet discharge head 1 uses a piezoelectric element 50 of a thin film piezo, and shows an example of a side shooter system in which ink droplets are discharged from a nozzle provided on a surface portion (head surface) of a substrate.

  The ink droplet ejection mechanism portion of the droplet ejection head 1 has a laminated structure in which the nozzle substrate 10, the liquid chamber substrate 20, the vibration plate 30 and the protective substrate 40 are stacked. The nozzle substrate 10 is a SUS substrate having a thickness of 30 to 50 [μm], and the nozzles 11 are formed by pressing and polishing. The nozzle 11 communicates with the pressurized liquid chamber 12 of the liquid chamber substrate 20. The liquid chamber substrate 20 is an SOI substrate in which silicon is bonded to a silicon substrate via a silicon oxide film. The diaphragm 30 is formed with a silicon oxide film on the surface of the Si layer of the SOI substrate by applying a pyro-oxidation method. On the diaphragm 30, a piezoelectric element 50 having a multilayer structure of a lower electrode 51 that is a common electrode, a piezoelectric body (PZT) 52, and an upper electrode 53 that is an individual electrode is formed by etching the liquid chamber substrate 20. It is formed in a region facing the pressurized liquid chamber 12 formed. The lower electrode 51 and the upper electrode 53 use platinum films.

  A lower electrode 51 on the vibration plate 30, an interlayer insulating film 55 disposed between the upper electrode 53 and the wiring member 54, and a passivation film 56 serving as moisture resistance for protecting the wiring member 54 are provided on the upper and side surfaces of the piezoelectric element 50. It is arranged to cover. The lower electrode pad portion 57 is provided so as to be electrically connected to the wiring member 54 electrically connected to the lower electrode 51, and the upper electrode pad portion 58 is electrically connected to the upper electrode 53. 54 to be electrically connected.

  The protection substrate 40 is a substrate that forms a piezoelectric element protection space including the wiring member 54 that is electrically connected to the lower electrode 51 and the upper electrode 53, and serves as an ink flow path 59 that is a part of the common liquid chamber 14. Has a groove. Further, a plurality of supply holes are provided in the vibration plate 30 in a portion serving as a flow path for supplying ink from the ink flow path 59 which is a part of the common liquid chamber 14 of the protective substrate 40 to the pressurized liquid chamber of the liquid chamber substrate 20. The produced diaphragm filter 60 is provided.

Next, the manufacturing method of the laminated structure of the ink droplet discharge mechanism will be described with reference to FIGS. 4 and 5 which are process cross-sectional views showing the manufacturing process.
First, as shown in FIG. 4A, a silicon oxide film of 0.2 [μm] and silicon of 2.0 [μm] were bonded to the surface of a <100> silicon substrate 201 having a thickness of 400 [μm]. An SOI substrate is used. A silicon oxide film 202 of 0.3 [μm] is formed on the surface of the SOI substrate by a pyro oxidation method, and this is used as a diaphragm 30. Thereafter, as shown in FIG. 4B, a platinum (Pt) layer 203 to be the lower electrode 51 is deposited by sputtering to a thickness of 0.2 [μm] and patterned. Further, as shown in FIG. 4C, the piezoelectric layer 204 to be the piezoelectric body 52 is formed by 2 [μm] by the sol-gel method, and further the platinum (Pt) layer 205 to be the upper electrode 53 is 0.1 [ μm] is formed. Thereafter, the platinum (Pt) layer 205 to be the upper electrode 53 and the piezoelectric layer 204 to be the piezoelectric body 52 are patterned by lithoetching. In the patterning process of the platinum (Pt) layer 205 to be the upper electrode 53, a resistance temperature detector (not shown) as a temperature sensor is manufactured at the same time.

  Next, as shown in FIG. 4D, an insulator layer 206 to be an interlayer insulating film 55 is formed by plasma CVD method to 0.3 [μm], and a via hole 207 for making wiring contact by lithoetch method is formed. Form. On the insulator layer 206, an upper conductive portion 208, a lower conductive portion 209, and a through portion 210 are patterned. The upper conductive portion 208 is a conductive portion between the wiring member 54 and the upper electrode 53 to be formed next, and the lower conductive portion 209 is a conductive portion between the lower electrode pad portion 57 and the lower electrode 51 that are bypass wiring members. . The penetrating portion 210 is an opening that becomes an ink flow path 59 from the common liquid chamber 14 to the pressurized liquid chamber 12.

  Further, as shown in FIG. 4E, an extraction electrode layer 211 to be the wiring member 54 is formed of an aluminum material. Since the lead electrode layer 211 receives stress due to vibration of the vibration plate 30 driven by the piezoelectric body 52, the lead electrode layer 211 is formed with a thick film thickness of about 1 [μm] using a soft aluminum material so as not to be disconnected by vibration. Yes.

  Next, as shown in FIG. 4F, a silicon nitride film 212 of 2 [μm] is formed by plasma CVD as a passivation film 56 for protecting the lead electrode layer 211 and patterned. Then, the portion that becomes the ink supply hole of the silicon oxide film 202 that becomes the vibration plate 30 is etched in advance. Instead of simply opening the ink supply holes, the diaphragm filter 60 is formed by forming a plurality of supply holes smaller than the inner diameter of the nozzle 11 in the member of the diaphragm. By simply changing the mask for forming the supply hole, the manufacturing process is the same as that for forming a large opening. Therefore, the diaphragm filter 60 for preventing foreign matter intrusion can be manufactured without increasing the cost.

  Thereafter, as shown in FIG. 5A, gold is laminated by a plating method to simultaneously form an upper electrode pad portion 58 serving as an individual electrode pad portion and a lower electrode pad portion 57 serving as a common electrode pad portion. . By forming the upper electrode pad portion 58 and the lower electrode pad portion 57 from gold, electrical connection with a driver circuit (not shown) is connected by low-temperature wire bonding. Gold has a low resistance value, and has a great effect of reducing the resistance values of the upper electrode 53 and the lower electrode 51. Further, the lower electrode pad portion 57 may be formed separately from the upper electrode pad portion 58, and copper, aluminum, or the like may be used as a material for the pad portion. In that case, the upper electrode pad portion 58 that is not protected from the outside may require a protective layer that protects against corrosion.

  Thereafter, as shown in FIG. 5B, a protective substrate 40 in which a column is separately formed by blasting a glass substrate is bonded to the silicon nitride film 212 side serving as a passivation film. Then, as shown in FIG. 5C, the surface of the silicon substrate 201 opposite to the side to which the protective substrate 40 is bonded is polished until the silicon substrate 201 has a desired thickness as the liquid chamber substrate 20. The protective substrate 40 may be a silicon substrate obtained by processing a recess by a lithoetch method, or a silicon substrate processed by wet etching using an alkaline etching solution such as TMAH or KOH. Further, it may be a molded part such as a resin mold or a metal injection mold. In addition, when the driver circuit is integrally formed on the actuator substrate, an oxide film formed by a pyro-oxidation method is formed by a LOCOS oxidation method, and a driver circuit is formed on the same substrate by selecting an oxide film formation region. You can also

  After that, as shown in FIG. 5C, concave portions to be the pressure liquid chamber 12, the fluid resistance portion 13, and the ink supply portion are formed on the opposite surface of the liquid chamber substrate 20 formed from the silicon substrate 201 by ICP dry etching. . Finally, as shown in FIG. 5 (d), the nozzle substrate 10 in which the nozzles 11 are separately formed on the SUS substrate having a thickness of 30 to 50 [μm] by pressing and polishing is used as the flow path partition of the liquid chamber substrate 20. Adhere to the forming surface. The wiring member connected to the upper electrode 53 and the lower electrode 51 of the piezoelectric element 50 is connected to the drive circuit. As a result, the laminated structure that becomes the ink droplet ejection mechanism portion of the droplet ejection head 1 shown in FIG. 3 is completed.

  FIG. 6 is an exploded perspective view of a molded body 85 constituting another part of the droplet discharge head. FIG. 7 shows a cross-sectional view of a molded body 85 constituting another part of the droplet discharge head. By bonding this molded body 85 to the protective substrate 40 side of the ink droplet ejection mechanism described above, an ink supply path to the ink droplet ejection mechanism formed by a laminated structure is formed. The molded body 85 includes a common liquid chamber constituting member 70 that forms the upper part of the common liquid chamber 14, and a housing member 80 having a communication pipe 81 that serves as an ink flow path from an ink tank (not shown) to the common liquid chamber 14. Have. 6 and 7 show ink supply paths for all four colors.

  The common liquid chamber constituting member 70 is composed of a rectangular metal plate 71 and an elongated surrounding wall member 72. In the metal plate 71, four slit-shaped openings 73 are formed corresponding to each color of Y, M, C, and K.

  As the material of the metal plate 71, stainless steel is used and formed by pressing. In the metal plate 71, a raised bone portion 74 that crosses the slit-like opening 73 is formed at the center in the extending direction of the slit-like opening 73.

  As shown in FIG. 7, the raised bone portion 74 has a pair of standing wall portions 74 a that are erected from the metal plate 71 and face the slit-like opening 73 therebetween. Moreover, it has the top wall part 74b bent in the direction which crosses the slit-shaped opening 73 from the top part of a pair of standing wall part 74a, and connecting a pair of standing wall part 74a mutually. The top wall 74b is formed with a through-hole 74c that communicates a communication pipe 81 (described later) with the common liquid chamber 14. The raised bone portion 74 plays a role of strengthening the metal plate 71 itself, a role of installing and fixing the communication pipe 81 to the metal plate 71, and a role of maintaining the shape stability of the surrounding wall member 72.

  The surrounding wall member 72 is a member narrowed toward the pressurized liquid chamber side toward the end portion. As shown in FIG. 8, the surrounding wall member 72 cooperates with the metal plate 71 to place the upper portion of the common liquid chamber 14 therein. It is composed. As the material of the surrounding wall member 72, a thermoplastic elastomer resin is used. The wall thickness of the surrounding wall member 72 is, for example, not less than 0.1 [mm] and not more than 0.3 [mm], and the Young's modulus thereof is, for example, 2 [megapascal] or less. The surrounding wall member 72 is formed in the common liquid chamber constituting member 70 integrated with the metal plate 71 by inserting and molding the metal plate 71.

  The housing member 80 and the communication pipe 81 are integrated with the common liquid chamber constituting member 70 by injection molding using a resin material different from the thermoplastic elastomer resin, for example, polyphenylene sulfide (PPS resin material) having corrosion resistance. Formed. Polyphenylene sulfide is filled with about 50% to 60% by weight of glass fiber.

  As a result, the linear expansion coefficient of polyphenylene sulfide is brought as close as possible to the linear expansion coefficient of the metal plate 71, and the occurrence of distortion due to the temperature between the metal plate 71 and the housing member 80 is prevented. It has a structure that does not deform as much as possible.

  The communication pipe 81 has an opening 81a communicating with an ink tank (not shown) in the upper part thereof and an opening 81b communicating with the inside of the common liquid chamber 14 through a through hole 74c in the lower part thereof. .

  In this droplet discharge head, the slit-like opening 73 of the metal plate 71 of the common liquid chamber constituting member 70 and the ink flow path 59 of the protective substrate 40 are joined so as to communicate with each other, thereby communicating with the pressurized liquid chamber 12. A common liquid chamber 14 is formed.

Here, the problem of the conventional droplet discharge head will be described.
In the droplet discharge head, bubbles may be mixed into the ink when the ink cartridge is replaced. If air bubbles are mixed in the ink, even if the actuator is driven to increase the pressure of the ink, a predetermined pressure may not be obtained and an ejection failure may be caused. In order to suppress such discharge failure, it is essential to discharge bubbles mixed in the ink in the droplet discharge head. The ink is discharged by being sucked from the nozzle by a suction means (not shown) of the recovery device 127 of the ink jet recording apparatus. In particular, in a droplet discharge head or the like in which the ink tank is miniaturized without providing an air release valve in the ink tank, air bubbles mixed during replacement of the ink cartridge are sucked by a suction unit (not shown) of the recovery device 127 of the ink jet recording apparatus. Discharging by suction from the nozzle. For this reason, it is an important issue to improve the bubble discharge performance.

  On the other hand, in an ink jet recording apparatus, in order to ensure that ink droplets ejected from the droplet ejection head land on the paper, the ink droplets are ejected in the direction of gravity from the nozzles formed on the lower surface of the droplet ejection head. Is preferred. In addition, the ink droplet ejection direction is the gravity direction, which means that the mist generated when the ink droplet is ejected returns to the nozzle, and the nozzle surface is soiled to prevent ejection bending and non-ejection. This is also preferable.

  In such a droplet discharge head, when air bubbles mixed in the ink are discharged, the ink is sucked from the nozzle downward in the gravitational direction by the suction means, and bubbles lighter than the ink are added downward from the common liquid chamber 14. It will flow through the pressurized fluid chamber 12 and be discharged. Here, in order to obtain good bubble discharge properties, it is necessary to have a flow rate that allows the bubbles to flow completely, and to have a flow channel shape in which bubbles do not stay in the upper part in the direction of gravity.

  In order to obtain a flow rate sufficient to allow the bubbles to flow, it is preferable to increase the flow rate by reducing the cross-sectional area of the ink flow path of the common liquid chamber 14. However, simply reducing the cross-sectional area of the ink flow path increases the fluid resistance, and when the amount of ejected droplets increases, bubbles are likely to be entrained from the nozzles due to excessive negative pressure due to pressure loss. Further, the pressure interference in the common liquid chamber 14 becomes large, which causes variations in the drop velocity from each nozzle. Accordingly, a damper mechanism for pressure buffering is provided in the common liquid chamber 14, or the common liquid chamber 14 is directed toward the end in the nozzle row direction so as to reduce the cross-sectional area of the common liquid chamber 14 toward the end where the flow rate decreases. It is known that the width of the is narrowed.

Furthermore, the droplet discharge head 1 of the present embodiment has a flow path shape in which bubbles do not stay in the upper part in the direction of gravity.
FIG. 8 is a cross-sectional explanatory view in the nozzle row direction schematically showing the ink flow path of the droplet discharge head 1 of the present embodiment. The upper part of the common liquid chamber 14 is formed by a common liquid chamber constituting member 70 including a metal plate 71 and the surrounding wall member 72, and the lower part thereof is formed by an ink flow path 59 of the protective substrate 40. The surrounding wall member 72 constituting the uppermost part of the common liquid chamber 14 has an inner wall surface on the side opposite to the pressurized liquid chamber 12 approaching the pressurized liquid chamber side toward the end, and the common liquid chamber 14 is The shape is constricted (hereinafter referred to as “Z constriction”) toward the pressurized liquid chamber side which is downward in the gravitational direction (Z direction in the figure) toward the end. Hereinafter, this Z-constricted portion is referred to as a Z-constricted portion 76.

  As shown in FIG. 8, in the common liquid chamber 14, the ink supplied into the common liquid chamber 14 via the communication pipe 81 passes through the common liquid chamber 14 at the end in the nozzle row direction (X direction in the figure). It flows toward you. When the bubble a mixed in the ink is pushed out to the end portion of the common liquid chamber 14 by the flow of ink, the bubble a flows toward the pressurized liquid chamber 12 below because the end portion is narrowed by Z. It becomes easy. Thereby, when the ink is sucked from the nozzle 11 by the suction means (not shown) of the recovery device 127, an excellent bubble discharge property is obtained.

  Further, in the droplet discharge head 1 of the present embodiment, the bubble discharge dummy liquid chamber 15 communicating with the common liquid chamber 14 is provided at the outermost end portion outside the pressurized liquid chamber 12 to improve the bubble discharge performance. ing. The bubble discharge dummy liquid chamber 15 will be described in detail later.

  However, in the common liquid chamber 14 having the Z constricted portion 76 at the end, reflection of the pressure fluctuation propagated to the common liquid chamber is remarkably increased at the end, and accordingly, crosstalk at the end is increased. Here, since the droplet discharge head 1 uses a deformable thermoplastic elastomer resin as the material of the surrounding wall member 72, the entire wall absorbs pressure vibration propagated from the pressurized liquid chamber 12 during droplet discharge. The common liquid chamber 14 serves as a damper film.

  FIG. 13 is an explanatory diagram of an example of a malfunction in the ejection state of a droplet ejection head provided with a common liquid chamber provided with a Z constriction portion at the end, and the ink droplets ejected from the center of the nozzle row and the end of the nozzle row This is a photograph of the ejection state of ink droplets ejected from the section. In this droplet discharge head, a phenomenon occurs in which the discharge speed is gradually decreased due to the influence of crosstalk toward the end of the common liquid chamber.

Therefore, in the droplet discharge head 1 of the present embodiment, a damper mechanism is provided at the end portion on the pressurized liquid chamber 12 side so as to correspond to the Z constriction portion 76 at the end portion of the common liquid chamber 14. Hereinafter, description will be given based on Examples 1 to 4.
<Example 1>
FIG. 9 is a schematic view of the pressurized liquid chamber 12 of the droplet discharge head 1 according to the first embodiment when viewed from the diaphragm 30 side. Each pressurized liquid chamber 12 communicates with the ink flow path 59 of the protective substrate 40 that forms the lowermost portion of the common liquid chamber 14 via the diaphragm filter 60. A bubble discharge dummy liquid chamber 15 as a first dummy liquid chamber is provided at the outermost end in the nozzle row direction outside the pressurized liquid chamber 12. The bubble discharge dummy liquid chamber 15 communicates with the bubble discharge nozzle 18 and has a large opening 61 formed in the vibration plate 30 at a communication portion with the ink flow path 59 of the protective substrate 40. The bubble discharge dummy liquid chamber 15 is not a diaphragm filter 60 composed of a plurality of small supply holes formed in the diaphragm 30 like the other pressurizing liquid chambers 12, but a large opening. By setting it to 61, it becomes easy to enter bubbles from the common liquid chamber 14.

  Further, the bubble discharge dummy liquid chamber 15 is not provided with the island-shaped fluid resistance portion 13 unlike the other pressurized liquid chambers 12, and the internal fluid resistance is obtained by making the cylinder width of the liquid chamber width. The value is made small so that ink can flow easily. For this reason, at the time of suction from the bubble discharge nozzle 18 by the suction means (not shown) of the recovery device 127, the flow velocity in the bubble discharge dummy liquid chamber 15 can be increased, and the bubbles are more easily discharged. That is, the bubble discharge dummy liquid chamber 15 is a dummy liquid chamber that is not used for ink droplet ejection for image formation. By providing such a bubble discharge dummy liquid chamber 15, the bubble discharge performance is improved.

  Further, a damper mechanism is provided outside the pressurized liquid chamber 12 and inside the bubble discharge dummy liquid chamber 15 in the nozzle row direction. Specifically, a portion of the diaphragm 30 corresponding to the ink flow path 59 constituting the lower portion of the common liquid chamber 14 in the region between the bubble discharge dummy liquid chamber 15 and the pressurized liquid chamber 12 is used as the common liquid. It is used as a diaphragm damper 62 that functions as a damper film that deforms due to pressure fluctuations in the chamber 14. A concave space (not shown) for deforming the diaphragm damper 62 is formed in the liquid chamber substrate 20 corresponding to the diaphragm damper 62. The thickness of the diaphragm damper 62 that functions as a damper film is preferably thinner than other regions of the diaphragm 30 in order to obtain good deformability.

In this configuration, the diaphragm damper 62 that forms the wall surface of the common liquid chamber outside the pressurizing liquid chamber 12 on the side of the pressurizing liquid chamber is used for the pressure fluctuation in the Z constriction portion 76 of the common liquid chamber 14. It is relieved by deforming to the concave space (not shown) side formed in 20. In this way, by providing the damper mechanism using the wall surface of the common liquid chamber 14 on the pressurized liquid chamber side corresponding to the Z constriction portion 76 at the end of the common liquid chamber 14, pressure interference due to Z constriction. Can be greatly relaxed. For this reason, the crosstalk at the end portion can be satisfactorily suppressed, and good discharge performance can be obtained.
According to the experiments by the present inventors, the phenomenon that the droplet velocity decreases toward the end in the nozzle row direction shown in FIG. 13 is suppressed to the same extent as the variation in the center of the nozzle row.

<Example 2>
FIG. 10 is a schematic view of the pressurized liquid chamber of the droplet discharge head of Example 2 as viewed from the diaphragm side. In the second embodiment, three dummy liquid chambers that are not used for ejecting ink droplets for image formation are formed at the end portion outside the pressurized liquid chamber 12 in the nozzle row direction. Of these, the dummy liquid chamber at the end is used as a bubble discharge dummy liquid chamber 15 (first dummy liquid chamber), and the other two dummy liquid chambers are used as damper dummy liquid chambers 16 (second dummy liquid chambers). The damper mechanism is used as a chamber. The configuration of the bubble discharge dummy liquid chamber 15 which is the endmost part in the nozzle row direction is the same as that of the first embodiment, and it becomes easy to discharge the bubbles through the bubble discharge dummy liquid chamber 15 so that the bubbles can be discharged. Will improve.

  The damper dummy liquid chamber 16 used as the damper mechanism closes the communicating portion with the ink flow path 59 constituting the lower part of the common liquid chamber 14 with the diaphragm 30. The closed portion of the diaphragm 30 is used as a diaphragm damper 62 that functions as a damper film that deforms due to pressure fluctuations in the corresponding common liquid chamber 14, and the damper dummy liquid chamber 16 is closed by the diaphragm damper 62. The inner space is used as a space for the diaphragm damper 62 to deform. That is, the damper dummy liquid chamber 16 is not a liquid chamber in which ink is supplied and ink droplets are discharged, but is a second dummy liquid chamber having a damper function. The thickness of the diaphragm damper 62 that functions as a damper film is preferably thinner than other regions of the diaphragm 30 in order to obtain good deformability.

  In this configuration, the pressure fluctuation in the Z constriction portion of the common liquid chamber 14 is caused by the vibration damper 62 of the damper dummy liquid chamber 16 disposed below the Z constriction portion 76 in the space side inside the damper dummy liquid chamber 16. It is relieved by deforming to. Thus, by providing a damper mechanism on the pressurized liquid chamber 12 side corresponding to the Z constriction 76 at the end of the common liquid chamber 14, pressure interference due to the Z constriction can be greatly relieved, and at the end. Crosstalk is suppressed. According to the experiments by the present inventors, the problem that the drop velocity decreases toward the end of the pressurized liquid chamber row shown in FIG. 14 is suppressed to the same extent as the variation in the pressurized liquid chamber row. .

  Further, the damper dummy liquid chamber 16 preferably forms the fluid resistance portion 13 similar to the pressurized liquid chamber 12. This ensures the rigidity of the damper dummy liquid chamber 16 as a structure and repeats the same liquid chamber configuration as that of the pressurized liquid chamber 12, thereby varying the discharge characteristics of the pressurized liquid chamber 12 at the end. Can be suppressed. During the flow path formation etching of the liquid chamber substrate 20, etching unevenness occurs due to a pattern change. Therefore, by forming the damper dummy liquid chamber 16 having the above-described configuration, an effect of preventing the etching unevenness unique to the end can be obtained. For this reason, it is preferable that the dummy dummy liquid chamber 16 has a structure close to that of the pressurized liquid chamber 12.

  10 shows a configuration in which one bubble discharge dummy liquid chamber 15 and two damper dummy liquid chambers 16 are provided, the number of liquid chambers is not limited to this. In order to improve the bubble discharge performance, it is suitable to arrange the bubble discharge dummy liquid chamber 15 at the extreme end, but otherwise, the damper dummy liquid chamber 16 and the bubble discharge dummy liquid chamber are alternately arranged. Nesting may be provided, or the number may be increased.

<Example 3>
FIG. 11 is a schematic view of the pressurized liquid chamber of the droplet discharge head of Example 3 as viewed from the diaphragm side. In the third embodiment, in the configuration of the second embodiment, the flow path partition wall of the two damper dummy liquid chambers 16 facing the ink flow path 59 is removed, the connecting portion is closed by the vibration plate 30, and the vibration plate damper 62. Is formed. As a result, the area of the diaphragm damper 62 and the space corresponding thereto is increased, and the compliance of the damper mechanism can be increased, and the pressure fluctuation in the Z constriction portion of the common liquid chamber is more effectively mitigated. Further, by leaving the flow path partition wall other than the part facing the ink flow path 59, the rigidity of the damper dummy liquid chamber 16 is ensured, and the discharge characteristics of the pressurized liquid chamber 12 at the end part vary. That can be suppressed. This configuration can be easily realized because only the mask pattern of the liquid chamber substrate 20 is changed and there is no process change.

  In FIG. 11, two damper dummy liquid chambers 16 are connected to increase the area of the diaphragm damper 62. However, the number of damper dummy liquid chambers 16 to be connected may be increased. Similarly to the second embodiment, the damper dummy liquid chamber 16 and the bubble discharge dummy liquid chamber 15 may be nested or the number thereof may be increased.

<Example 4>
FIG. 12 is a schematic view of the pressurized liquid chamber of the droplet discharge head of Example 4 as viewed from the diaphragm side. In the fourth embodiment, five dummy liquid chambers that are not involved in the image formation are formed at the end portion outside the pressurizing liquid chamber in the nozzle row direction. The dummy liquid chamber 17 adjacent to the pressurized liquid chamber has the same flow path shape as the pressurized liquid chamber 12 except that the diaphragm filter 60 is not formed and a large opening 61 is formed in the diaphragm 30. doing. The two liquid chambers adjacent to the end portions are the same as in the above-described third embodiment, except that the portion connected to the ink flow channel 59 by removing the flow channel partition wall is closed by the vibration plate 30 and the vibration plate damper is closed. This is a dummy dummy liquid chamber 16. The two liquid chambers at the extreme ends in the nozzle row direction are bubble discharge dummy liquid chambers 15, which are connected by removing the flow channel partition wall facing the ink flow channel to form a large opening 61. .

  Here, in the dummy liquid chamber 17 adjacent to the pressurized liquid chamber 12, a fluid resistance portion 13 similar to that of the pressurized liquid chamber 12 is formed, and the same flow path pattern as that of the pressurized liquid chamber 12 is formed. Thereby, the etching nonuniformity by the pattern change at the time of the flow path formation etching of the liquid chamber board | substrate 20 can be suppressed, and the dispersion | variation in the discharge characteristic of the pressurization liquid chamber 12 edge part can be suppressed. The dummy liquid chamber 17 adjacent to the pressurized liquid chamber 12 has a larger internal fluid resistance than the bubble discharging dummy liquid chamber 15, but bubbles are more likely to enter than the pressurized liquid chamber 12, so that the bubbles are discharged. Can be improved.

  Further, the two bubble discharge dummy liquid chambers 15 which are the extreme ends in the nozzle row direction are connected as described above to form a large opening 61, so that the bubbles a enter the bubble discharge dummy liquid chamber 15. It becomes easy to do and bubble discharge nature improves. These can be easily realized because only the mask pattern for forming the liquid chamber is changed and the process is not changed.

  As described above, in the present embodiment, ink is supplied into the common liquid chamber 14 from the supply port that is the communication pipe 81 in the center in the nozzle row direction, and the ink in the common liquid chamber 14 is directed toward both ends in the nozzle row direction. The present invention has been described using a so-called centrally-supplied T-shaped common liquid chamber 14 through which the water flows. However, it is not limited to such a common liquid chamber, but ink is supplied from the supply port at one end in the nozzle row direction, and the ink flows in the common liquid chamber toward the other end in the nozzle row direction. An L-shaped common liquid chamber may be used. In this case, the common liquid chamber is narrowed to the pressurized liquid chamber side toward the end opposite to the supply port, which is on the downstream side in the flow direction of the ink flowing into the common liquid chamber. A damper mechanism or a bubble discharge dummy liquid chamber may be provided at the end of the corresponding pressurized liquid chamber.

  In the present embodiment, the common liquid chamber constituting member 70 having the surrounding wall member 72 whose end portion is constricted to the pressurized liquid chamber side is joined to the upper portion of the protective substrate 40 in which the ink flow path 59 is formed. Thus, a common liquid chamber having a Z constriction at the end is formed. However, the present invention is not limited to this, and as the common liquid chamber is moved to the end in the arrangement direction, the inner wall surface on the side opposite to the pressurization liquid chamber is arranged on the pressure liquid chamber side so that the cross-sectional area perpendicular to the arrangement direction becomes smaller. As long as they are formed so as to be close to each other, a configuration using a common liquid chamber substrate may be used. Specifically, a common liquid chamber is formed by stacking a plurality of common liquid chamber forming substrates on the protective substrate 40 that form a step so that the inner wall surface approaches the pressurized liquid chamber side toward the end portion. It is also possible. Even in the configuration in which the common liquid chamber substrates are stacked to form the narrowed shape as described above, the same effect can be obtained by providing the damper mechanism at the end of the pressurized liquid chamber corresponding to the narrowed portion. However, compared to this configuration, the configuration of the present embodiment is superior in terms of structure and cost to form a common liquid chamber having a Z constriction.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A plurality of pressurizing liquid chambers 12 communicating with the plurality of nozzles 11 and provided so as to extend in the direction of gravity above the pressurizing liquid chamber 12 in the direction of arrangement of the pressurizing liquid chambers (nozzle row direction). A liquid droplet ejection head 1 having a common liquid chamber 14 that communicates with the chamber and supplies a liquid such as ink, and a pressure generation unit that generates pressure fluctuations in the pressurized liquid chamber 12 so as to eject liquid droplets from the nozzle 11. It is. In this droplet discharge head 1, the common liquid chamber 14 is pressurized so that the cross-sectional area perpendicular to the arrangement direction becomes smaller as it goes to the end in the arrangement direction, which is the downstream side in the flow direction of the liquid flowing in the common liquid chamber. The pressurized liquid chamber of the common liquid chamber 14 part formed so that the inner wall surface on the opposite side to the liquid chamber 12 is made closer to the pressurized liquid chamber side and extended outward from the pressurized liquid chamber 12 in the arrangement direction. The side wall surface is configured to be deformable.

  In (Aspect A), the inner wall surface on the side opposite to the pressurized liquid chamber approaches the pressurized liquid chamber side so that the cross-sectional area perpendicular to the arranged direction decreases as the common liquid chamber goes to the end in the arranged direction. By doing so, the bubbles pushed out to the end portion of the common liquid chamber can easily flow to the lower pressurized liquid chamber, and the bubble discharge performance is improved. In addition, the common liquid chamber is configured such that the wall surface on the pressurized liquid chamber side of the common liquid chamber portion extended outward from the pressurized liquid chamber in the arrangement direction can be deformed, so that the common liquid chamber has a pressure fluctuation at the end in the arrangement direction. A damper mechanism for relaxing is provided on the pressurized liquid chamber side. By the damper mechanism on the pressurized liquid chamber side at the end, pressure fluctuation due to the end shape of the common liquid chamber can be reduced. For this reason, the crosstalk at the end portion can be satisfactorily suppressed, and good discharge performance can be obtained.

(Aspect B)
(Aspect A) includes the diaphragm 30 that forms the wall surface of the pressurized liquid chamber 12 on the common liquid chamber 14 side, and uses the region outside the pressurized liquid chamber in the arrangement direction of the diaphragm to A diaphragm damper 62, which is a deformable wall on the pressurized liquid chamber side of the chamber portion, is formed. According to this, as described in the first embodiment, the deformable wall surface of the damper mechanism is formed using the diaphragm that forms the pressurized liquid chamber. In this configuration, the damper mechanism can be easily formed at the end of the common liquid chamber on the pressurized liquid chamber side using a conventional manufacturing process without using a member that newly forms the damper mechanism.

(Aspect C)
In (Aspect A) or (Aspect B), an opening 61 that communicates with the bubble discharge nozzle 18 at the outermost end outside the pressurizing liquid chamber in the arrangement direction and that is larger than the pressurizing liquid chamber 12 is provided. A first dummy liquid chamber such as a bubble discharge dummy liquid chamber 15 communicating with the common liquid chamber 14 is provided. According to this, the bubble pushed out to the endmost part of the common liquid chamber by the flow of the liquid in the common liquid chamber easily enters the first dummy liquid chamber having a larger opening than the other pressurized liquid chambers. And discharged from the nozzle of the first dummy liquid chamber. In this manner, the bubble discharge performance is improved by discharging the bubbles through the first dummy liquid chamber.

(Aspect D)
In (Aspect B) or (Aspect C), a second dummy such as a dummy dummy liquid chamber 16 for a damper having a diaphragm 30 closing a communication portion with the common liquid chamber outside the pressurized liquid chamber 12 in the arrangement direction. A liquid chamber is provided, and a deformable wall on the pressurized liquid chamber side of the common liquid chamber is formed by using a portion of the diaphragm, such as the diaphragm damper 62, whose communication portion is closed. According to this, as described in the second embodiment, the deformable wall surface of the damper mechanism is formed at the portion where the communication portion of the second dummy liquid chamber with the common liquid chamber is closed by the diaphragm. The space inside the second dummy liquid chamber can be used as a space for deforming the wall surface. In this configuration, the damper mechanism can be easily formed at the end of the common liquid chamber on the pressurized liquid chamber side using a conventional manufacturing process without using a member that newly forms the damper mechanism.

(Aspect E)
In (Aspect D), a plurality of second dummy liquid chambers such as the damper dummy liquid chamber 16 are provided, and the communicating portions of the plurality of second dummy liquid chambers with the common liquid chamber are connected and closed with a diaphragm. According to this, as described in the third embodiment, the area of the damper mechanism can be increased by connecting the communication portions of the plurality of second dummy liquid chambers with the common liquid chamber, and more effectively. The pressure fluctuation at the end can be reduced. Moreover, the rigidity as a structure of a 2nd dummy liquid chamber is securable by leaving flow-path partition walls other than a connection part with the common liquid chamber of a 2nd dummy liquid chamber.

(Aspect F)
In any one of (Aspect B) to (Aspect E), the first dummy liquid chamber such as the bubble discharge dummy liquid chamber 15 is connected to the nozzle from the communicating portion with the common liquid chamber as compared with the pressurized liquid chamber 12. It forms so that fluid resistance may become small. According to this, the flow velocity of the liquid can be increased in the first dummy liquid chamber, and the bubbles can be easily discharged through the first dummy liquid chamber, thereby improving the bubble discharge performance.

(Aspect G)
In (Aspect D) or (Aspect E), the flow path shape inside the first dummy liquid chamber or the second dummy liquid chamber adjacent to the pressurization liquid chamber is the flow path inside the pressurization liquid chamber 12. The shape is the same. According to this, as described in the second or fourth embodiment, the pressure liquid chamber is provided by providing the dummy liquid chamber having the same flow channel shape as the pressure liquid chamber adjacent to the pressure liquid chamber row. It is possible to improve the processing accuracy of the row end and reduce the discharge variation in the pressurized liquid chamber row.

(Aspect H)
An image forming apparatus such as an ink jet recording apparatus comprising the droplet discharge head according to any one of (Aspect A) to (Aspect G) and a suction unit that sucks an internal liquid from a nozzle of the droplet discharge head. According to this, good discharge performance can be obtained, and a high-quality image can be obtained.

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 10 Nozzle board | substrate 11 Nozzle 12 Pressurization liquid chamber 13 Fluid resistance 14 Common liquid chamber 15 Bubble discharge dummy liquid chamber (1st dummy liquid chamber)
16 Dummy liquid chamber for damper (second dummy liquid chamber)
17 Dummy liquid chamber 18 adjacent to pressurized liquid chamber 18 Bubble discharge nozzle 20 Liquid chamber substrate 30 Vibration plate 40 Protective substrate 50 Piezoelectric element 51 Lower electrode 52 Piezoelectric body 53 Upper electrode 54 Wiring member 55 Interlayer insulating film 56 Passivation film 57 Lower portion Electrode pad part 58 Upper electrode pad part 59 Ink flow path (common liquid chamber lower part)
60 Diaphragm filter 61 Opening 62 Diaphragm damper 70 Common liquid chamber component (upper common liquid chamber)
71 Metal plate 72 Surrounding wall member 73 Slit-shaped opening 74 Raised bone portion 76 Z constricted portion 80 Housing member 81 Communication tube 85 Molded body 100 Inkjet recording device 101 Carriage 102 Ink cartridge 103 Printing mechanism portion 104 Paper feed mechanism portion 127 Recovery device 201 Silicon substrate 202 Silicon oxide film 203, 205 Platinum (Pt) layer 204 Piezoelectric layer 206 Insulator layer 211 Lead electrode layer 212 Silicon nitride film

JP2013-169683A JP 2011-056729 A

Claims (8)

A plurality of pressurizing fluid chambers communicating with the plurality of nozzles, and provided so as to extend in the direction of gravity above the pressurizing fluid chamber in the direction of gravity, and communicate with the pressurizing fluid chambers. In a droplet discharge head comprising a common liquid chamber for supplying a liquid and a pressure generating means for generating a pressure fluctuation in the pressurized liquid chamber so as to discharge a droplet from the nozzle,
The common liquid chamber is opposite to the pressurized liquid chamber so that the cross-sectional area perpendicular to the arrangement direction decreases as it goes to the end in the arrangement direction, which is downstream in the flow direction of the liquid flowing in the common liquid chamber. The inner wall surface on the side is formed so as to approach the pressurized liquid chamber side, and the wall surface on the pressurized liquid chamber side of the common liquid chamber portion extended outside the pressurized liquid chamber in the arrangement direction A droplet discharge head configured to be deformable.   2. The liquid droplet ejection head according to claim 1, further comprising a diaphragm that forms a wall surface on the common liquid chamber side of the pressurizing liquid chamber, and using a region outside the pressurizing liquid chamber in the arrangement direction of the diaphragm. And a deformable wall surface of the common liquid chamber portion on the pressurized liquid chamber side.   3. The droplet discharge head according to claim 1, wherein the bubble discharge nozzle communicates with an outermost end outside the pressurizing liquid chamber in the arrangement direction and has a larger opening than the pressurizing liquid chamber. And a first dummy liquid chamber communicating with the common liquid chamber via the liquid droplet ejection head.   The liquid droplet ejection head according to claim 2 or 3, wherein a second dummy liquid chamber is provided outside the pressurizing liquid chamber in the arrangement direction and the communication portion with the common liquid chamber is closed by the diaphragm. A droplet discharge head, wherein a deformable wall on the pressurized liquid chamber side of the common liquid chamber portion is formed by using a diaphragm in a portion where the communication portion is closed. 5. The liquid droplet ejection head according to claim 4, wherein a plurality of the second dummy liquid chambers are provided, the communicating portions of the plurality of second dummy liquid chambers with the common liquid chamber are connected, and the diaphragm is closed. A droplet discharge head characterized by the above.   6. The liquid droplet ejection head according to claim 2, wherein the first dummy liquid chamber has a smaller fluid resistance from the communicating portion with the common liquid chamber to the nozzle than the pressurized liquid chamber. A droplet discharge head characterized by being formed in the above.   6. The liquid droplet ejection head according to claim 4, wherein a flow path shape inside the first dummy liquid chamber or the second dummy liquid chamber adjacent to the pressurizing liquid chamber is the pressure liquid chamber. A droplet discharge head having the same shape as an internal flow path.   An image forming apparatus comprising: the droplet discharge head according to claim 1; and a suction unit that sucks an internal liquid from a nozzle of the droplet discharge head.