JP2006297916A - Liquid discharge head, image forming device and manufacturing method of liquid discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a manufacturing process when a liquid discharge head is formed by laminating a plurality of plates. <P>SOLUTION: The liquid discharge head is formed by laminating a plurality of plates 21, 22, 23, 24 and 25 including a pressure chamber forming plate 22 in which a pressure chamber 52 communicating with nozzles 51 is formed, a vibrating plate 23 in which a piezoelectric element 58 is formed, and a common liquid chamber forming plate 25 in which a common liquid chamber 55 arranged on the side opposite to the side where the pressure chamber forming plate 22 is arranged, interspaced by the vibrating plate 23 and supplying a liquid to the pressure chamber 52, and electrical wiring 60 rising nearly vertically to the arrangement surface of the piezoelectric element 58 and penetrating at least a part of the common liquid chamber 55 are formed. Joints at least between the plates 23, 24 and 25 between the vibrating plate 23 and the common liquid chamber forming plate 25 and the electrical joint between the piezoelectric element 58 and the electrical wiring 60 are joined by an NCP (Non Conductive Paste) 30 having the same setting conditions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejection head, an image forming apparatus, and a method for manufacturing the liquid ejection head, and in particular, a liquid ejection head formed by stacking a plurality of plates, an image forming apparatus including the liquid ejection head, and The present invention relates to a method for manufacturing the liquid discharge head.

  Conventionally, an image is formed on a recording medium by ejecting ink from the nozzle toward the recording medium while relatively moving a liquid ejection head in which a plurality of nozzles are arranged and a recording medium such as paper. An image forming apparatus is known.

  As a liquid discharge head mounted in such an image forming apparatus, for example, ink is supplied to a pressure chamber communicating with a nozzle, and image data is applied to a piezoelectric element attached to the outside of the pressure chamber via a diaphragm. There is known a piezo-type liquid discharge head in which the volume of a pressure chamber is changed by supplying a drive signal corresponding to the pressure and ink in the pressure chamber is discharged from a nozzle.

  On the other hand, there is also known a thermal jet type liquid discharge head in which bubbles are generated by heating ink with a heating element such as a heater and the ink is blown by the pressure.

  By the way, when manufacturing a liquid discharge head, a method of forming a liquid discharge head by joining a plurality of plates is known. Further, when manufacturing a liquid discharge head, it is necessary to provide an electrode and an electric wiring for giving an electric signal to an actuator as a pressure generating means such as a piezoelectric element.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a structure in which a flow path substrate on which an ink flow path is formed and a vibration plate on which a piezoelectric element is formed are joined with a sheet adhesive, and the vibration plate and the piezoelectric element are joined with solder. Has been.

In Patent Document 2, a base plate in which an ink supply groove is formed and a heater board on which a heater is formed are joined with an adhesive, and the heater board and the heater driving IC are connected to an ACF (Anisotropic Conductive Film) or the like. What was joined by is described.
JP-A-9-277521 (particularly FIG. 1) Japanese Patent Laying-Open No. 2003-211677 (particularly FIG. 2)

  However, if the joining between the stacked plates and the electrical joining for giving an electrical signal to the actuator are performed in separate steps, it takes time and it is difficult to reduce the manufacturing cost.

  In addition, there is a demand for higher image quality, and in order to meet this demand, it is required to increase the density of the nozzles in a two-dimensional array. In order to achieve both the two-dimensional arrangement and the high density, it becomes a problem how to arrange the electric wiring, and it is necessary to provide an electric signal to the joint between the stacked plates and the actuator. The problem is how to actually perform electrical bonding.

  The present invention has been made in view of such circumstances, and a liquid discharge head capable of simplifying the manufacturing process when a liquid discharge head is formed by stacking a plurality of plates, and an image forming apparatus using the liquid discharge head And it aims at providing the manufacturing method of a liquid discharge head.

  In order to achieve the above object, the invention according to claim 1 is an actuator formation in which a flow path plate in which a liquid flow path is formed and an actuator that generates pressure when the liquid is discharged are formed. A plurality of plates including a plate, a joint portion between the flow path plate and the actuator forming plate, and an electrical joint portion for giving an electric signal to the actuator Are bonded with NCP (Non Conductive Paste) having the same curing conditions.

  NCP has a non-conductive high-purity resin as a main component. As a specific numerical value, the high purity is 95% by mass or more, more desirably 98% by mass or more. The NCP is attached to the joint portion in a paste state (or a liquid state), and is cured while contracting under a predetermined curing condition. Specific examples of NCP include those containing a high-purity epoxy resin as a main component.

  The mode of NCP adhesion is not particularly limited to the mode in which the same type of NCP is adhered to both the junction between the plates and the electrical junction, but both the junction between the plates and the electrical junction as curing conditions. An NCP that cures at least at the same temperature is used.

  In the liquid discharge head in a state where it is actually used, the NCP has already been removed from the paste state (or liquid state) and cured.

  According to the present invention, the joining between the stacked plates and the electrical joining for giving an electrical signal to the actuator can be performed simultaneously under the same curing conditions. Compared to a conventional liquid discharge head that needs to perform electrical joining for providing in separate steps, the manufacturing process is simplified, and the manufacturing cost can be reduced.

  In addition, since NCP has a very low content of sodium ions, the generation of insoluble substances eluted in the liquid is suppressed, and the occurrence of non-ejection of the nozzle is prevented. Further, since NCP has a very low chloride ion content, it is difficult to corrode even when a metal plate is used, and deterioration of discharge performance is prevented.

  According to a second aspect of the present invention, there is provided a pressure chamber forming plate in which a pressure chamber communicating with a liquid discharge port is formed, and an actuator forming plate in which an actuator that generates pressure when liquid is discharged is formed. A common liquid chamber that is disposed on the opposite side of the side where the pressure chamber forming plate is disposed across the actuator forming plate, and that supplies liquid to the pressure chamber; A plurality of plates including a common liquid chamber forming plate that is vertically formed and has an electrical wiring penetrating at least a part of the common liquid chamber, and is formed by laminating the actuator forming plate and the common liquid chamber forming The joint between the plates and the electrical joint between the actuator and the electrical wiring are cured in the same manner. To provide a liquid discharge head, characterized in that it joined the NCP with matter (Non Conductive Paste).

  In addition, the case where the plate (interposition plate) for protecting an actuator is interposed between the actuator forming plate and the common liquid chamber forming plate is included. In this case, the joint portion between the actuator forming plate and the interposing plate and the joint portion between the interposing plate and the common liquid chamber forming plate are joined together with the electrical joint portion by NCP having the same curing conditions. It becomes the composition which is done.

  On the other hand, when the actuator forming plate and the common liquid chamber forming plate are directly joined without an intervening plate interposed therebetween, a direct joint portion between the actuator forming plate and the common liquid chamber forming plate is used. However, it becomes the structure joined by NCP which has the same hardening conditions with an electrical junction part.

  According to the present invention, it is necessary to stretch the electrical wiring horizontally on the actuator placement surface by providing the electrical wiring that rises substantially perpendicular to the actuator placement surface and penetrates at least a part of the common liquid chamber. The two-dimensional arrangement and high density of the nozzles can be eliminated, and bonding between the plates and electrical bonding between the electrical wiring and the actuator can be performed simultaneously under the same curing conditions, simplifying the manufacturing process. Manufacturing costs can be reduced.

  The invention according to claim 3 is the liquid ejection head according to claim 2, wherein the same NCP is used for electrical connection with an FPC (Flexible Print Circuit) for taking out the electrical wiring. I will provide a.

  A fourth aspect of the present invention provides the liquid ejection head according to any one of the first to third aspects, wherein the NCP includes an inorganic filler having a size of 5 μm or less. .

  According to the present invention, it is possible to ensure the strength of the laminated structure while maintaining the NCP bonding function.

  According to a fifth aspect of the present invention, the liquid ejection head according to any one of the first to fourth aspects is provided, and an image is formed on the recording medium by the liquid ejected from the liquid ejection head onto the recording medium. An image forming apparatus is provided.

  According to a sixth aspect of the present invention, in the method of manufacturing a liquid discharge head formed by stacking a plurality of plates, a flow path plate in which a liquid flow path is formed, and a pressure when the liquid is discharged Preparing a plurality of plates including an actuator forming plate on which an actuator for generating electric current is formed, and at least a joint portion between the flow path plate and the actuator forming plate, and an electric signal to the actuator A step of adhering NCP (Non Conductive Paste) having the same curing condition to an electrical joining portion for giving, joining between the plate between the flow path plate and the actuator forming plate, and the actuator The step of simultaneously joining the electrical joints for applying an electrical signal to the curing conditions under the curing conditions. A method for manufacturing a liquid discharge head is provided.

  According to a seventh aspect of the present invention, in the method for manufacturing a liquid discharge head formed by stacking a plurality of plates, a pressure chamber forming plate in which a pressure chamber communicating with the liquid discharge port is formed, and the liquid is discharged. An actuator forming plate on which an actuator for generating pressure is formed, and a side opposite to the side on which the pressure chamber forming plate is arranged across the actuator forming plate, and a liquid is placed in the pressure chamber A plurality of plates including a common liquid chamber and a common liquid chamber forming plate in which electrical wiring that rises substantially perpendicular to the arrangement surface of the actuator and penetrates at least a part of the common liquid chamber is formed. , At least the joint between the actuator forming plate and the common liquid chamber forming plate, and the front A step of adhering NCP (Non Conductive Paste) having the same curing condition to an electrical joint portion between the actuator and the electric wiring, and at least a space between the actuator forming plate and the common liquid chamber forming plate And a step of simultaneously joining the actuator and the electrical wiring under the curing conditions. The method for manufacturing a liquid discharge head is provided.

  The NCP is attached to the joint part in such a manner that the paste (or liquid state) NCP is directly applied from the instrument to the joint part, the NCP is pre-attached on the sheet and transferred from the sheet, and the screen uses a mask. There are modes by printing. By using NCP in this way, the choice of coating method increases, and the degree of freedom of selection in consideration of the condition of the coated surface and cost merit increases.

  Further, if the curing conditions are the same, NCP may be attached in a manner different from the joint portion between the plates and the electrical joint portion.

  According to the present invention, the manufacturing process can be simplified and the manufacturing cost can be reduced as compared with the prior art in which the bonding between the plates and the electric bonding must be performed in separate processes.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a liquid discharge head 50 according to an embodiment of the present invention.

  In FIG. 1, the liquid discharge head 50 is formed by laminating a plurality of plates 21, 22, 23, 24, and 25.

  The nozzle forming plate 21 (also referred to as “nozzle plate”) is formed with a plurality of nozzles 51 (discharge ports) for discharging liquid.

  The pressure chamber forming plate 22 has a plurality of pressure chambers 52 communicating with the nozzles 51. The pressure chamber 52 can also be referred to as an individual flow path.

  The vibration plate 23 (also referred to as “actuator forming plate”) is disposed on the opposite side of the pressure chamber forming plate 22 from the side on which the nozzle forming plate 21 is disposed, and is applied to the ink in the pressure chamber 52. A plurality of piezoelectric elements 58 are formed as pressure generating means for generating the pressure.

  The piezoelectric element 58 is made of, for example, PZT. When a predetermined electric signal (driving signal) is given, the piezoelectric element 58 is displaced (distorted) and changes the volume of the pressure chamber 52 via the diaphragm 23.

  The vibration plate 23 forms a surface (vibration surface) opposite to the side where the nozzle 51 of each pressure chamber 52 is disposed, and functions as one electrode of the piezoelectric element 58.

  The diaphragm 23 in the present embodiment is common to the plurality of pressure chambers 52 and is formed of a single plate, but is not particularly limited to such a case, and is formed for each pressure chamber 52. There may be.

  The piezoelectric element protection plate 24 (also referred to as “piezo cover” or “intervening plate”) is configured so that the piezoelectric element 58 is freely displaced in the thickness direction (that is, to ensure the operation of the piezoelectric element 58). ), Space is secured and the piezoelectric element 58 is protected.

  The common liquid chamber forming plate 25 is disposed on the side opposite to the side where the pressure chamber forming plate 22 is disposed, with the vibration plate 23 and the piezoelectric element protection plate 24 interposed therebetween, and supplies ink to the pressure chamber 52. A common liquid chamber 55 and a plurality of columnar electric wires 60 are formed.

  The common liquid chamber 55 supplies ink to the plurality of pressure chambers 52 through the ink supply port 53. The common liquid chamber 52 can also be called a common flow path.

  When the nozzle 51 is viewed below the pressure chamber 52, the common liquid chamber 55 has a single common space so as to cover all of the plurality of pressure chambers 52 immediately above the plurality of pressure chambers 52. It is formed as a liquid chamber. By such a common liquid chamber 55, the ink is supplied to each pressure chamber 52 with a good refill property.

  In FIG. 1, the shape of the flow path from the common liquid chamber 55 to the pressure chamber 52 is an “L” shape for convenience of illustration, but is not particularly limited to such a shape. In order to give priority to the refilling property of the ink from the common liquid chamber 55 to the pressure chamber 52, it is preferable to have a shape (“I” shape) extending vertically from the common liquid chamber 55 toward the pressure chamber 52.

  The columnar electric wiring 60 is made of a conductive material, rises substantially perpendicular to the arrangement surface of the piezoelectric element 58 (that is, rises substantially perpendicular to the vibration plate 23), and from the bump electrode 64 of the piezoelectric element 58, a common liquid is formed. This is a columnar wiring that passes through the chamber 55 and reaches a bump electrode 66 of the flexible wiring board 26 described later. Such a columnar electric wiring 60 gives a drive signal to each piezoelectric element 58 with an area efficiency. That is, the pressure chamber 52 can be densified as compared with the case where the drive wiring is stretched in parallel with the arrangement surface of the piezoelectric element 58, thereby enabling the nozzle 51 to be densified.

  Note that the shape of the columnar electric wiring 60 is not particularly limited to a columnar shape or a prismatic shape. For example, the cross-sectional area may gradually increase (or decrease) and may have a tapered shape.

  An insulating protective film 68 (insulating protective film) is formed on the outer peripheral surface of the columnar electric wiring 60 (which is a surface in contact with the ink in the common liquid chamber 55).

  The flexible printed circuit 26 (FPC: Flexible Print Circuit) has a plurality of electrical wirings, and gives a drive signal to each piezoelectric element 58 via the columnar electrical wiring 60 of the common liquid chamber forming plate 25.

  The electrical wiring formed on the flexible wiring board 26 is joined to the columnar electrical wiring 60 via the bump electrodes 66 formed on the flexible wiring board 26. In other words, the bump electrode 66 of the flexible wiring board 26 is electrically connected to the columnar electric wiring 60. Specifically, the bump electrode 66 of the flexible wiring board 26 and the end 62 on the outer side (upper side in FIG. 1) of the columnar electric wiring 60 are fixed and joined by an NCP (Non Conductive Paste) 30.

  Further, the columnar electric wiring 60 is joined to the piezoelectric element 58 via a bump electrode 64 formed on the piezoelectric element 58. In other words, the columnar electrical wiring 60 is electrically connected to the bump electrode 64 of the piezoelectric element 58. Specifically, the bump electrode 64 of the piezoelectric element 58 and the end 61 on the inner side (lower side in FIG. 1) of the columnar electric wiring 60 are fixed and joined by the NCP 30.

  The common liquid chamber forming plate 25 and the piezoelectric element protection plate 24 are joined by NCP30. Similarly, the piezoelectric element protection plate 24 and the vibration plate 23 are joined by NCP30. Similarly, the diaphragm 23 and the pressure chamber forming plate 22 are joined by NCP30. Similarly, the pressure chamber forming plate 22 and the nozzle forming plate 21 are joined by NCP30. That is, all the joint portions between the plates are joined by NCP30.

  The NCP 30 is made of a non-conductive high-purity resin. As a specific numerical value, the high purity is 95% by mass or more, more desirably 98% by mass or more. The NCP 30 is attached to the joint portion in a paste state (or a liquid state), and is cured while shrinking at a predetermined temperature when heated in a state where the joint portions are pressure-bonded to each other. As a result, the bonded portions are fixed and sealed in a state where the bonded portions are securely bonded.

  As NCP30, for example, NCP made of high-purity epoxy resin is used.

  NCP30 has a very low content of sodium ions (Na +) (for example, less than 5 ppm). Thereby, generation | occurrence | production of the insoluble substance eluted in an ink is suppressed.

  NCP30 has a very low chloride ion (Cl-) content (for example, less than 15 ppm). Thereby, even if it uses a metal plate, it is hard to corrode.

  Needless to say, in a state in which the liquid ejection head 50 has been manufactured and used, the NCP 30 has already left the paste state (or liquid state) and has been cured.

  FIG. 2 is an enlarged view showing an enlarged electrical junction between the columnar electrical wiring 60 and the bump electrode 64 of the piezoelectric element 58.

  In FIG. 2, for convenience of explanation, the unevenness of the lower end portion 61 of the columnar electric wiring 60 is drawn slightly exaggerated. In practice, it is desirable that the bump electrode 64 has a columnar shape in which a plane exists on the upper part joined to the columnar electric wiring 60 as shown in FIG. As a result, the contact area between the bump electrode 64 and the columnar electric wiring 60 is increased, and the reliability of electrical connection is improved. When the columnar electric wiring 60 is pressure-bonded to such a bump electrode 64, the bump electrode 64 itself is deformed. As the material of the bump electrode 64, for example, Au is used. The NCP 30 is attached to the joint portion in a paste state (or a liquid state), and is cured while shrinking when heated in a state where the columnar electric wiring 60 and the bump electrode 64 are pressed. By such deformation of the bump electrode 64 and contraction of the NCP 30, a state where the columnar electric wiring 60 and the bump electrode 64 are securely bonded is formed, and is sealed and fixed. Bonding is ensured reliably. In other words, the NCP 30 has a function of joining an electrical joint portion and a function of sealing the electrical joint portion.

  The total of the height of the bump electrode 64 and the height of the electrode of the columnar electric wiring 60 (the protruding portion of the lower end portion 61) is preferably 10 to 100 μm. Accordingly, it is possible to prevent an electrical failure such as a short circuit due to excessive deformation of the bump electrodes 64 and 66 while securing an absorption white of the height variation due to the deformation of the bump electrodes 64 and 66.

  2 shows only the bump electrode 64 on the piezoelectric element 58 side, the bump electrode 66 on the flexible wiring 26 side shown in FIG. 1 also has a columnar shape in which a plane exists at the lower part joined to the columnar electric wiring 60. It is desirable to be. In addition, the total of the height of the bump electrode 66 and the height of the electrode of the columnar electric wiring 60 (the protruding portion of the upper end portion 62) is desirably 10 to 100 μm.

  In the example shown in FIG. 2, a large number of minute inorganic fillers 31 are included in the NCP 30.

  As a basic function of the inorganic filler 31, there is adjustment of viscosity or adjustment of thermal expansion coefficient. In the present embodiment, the size (corresponding to the diameter) of the inorganic filler 31 is 5 μm or less. Thereby, while maintaining the adhesion function of NCP30, the rigidity of the joined portion is further prevented from decreasing and the strength of the laminated structure is ensured.

[Flow of manufacturing process]
An example of the manufacturing process of the liquid ejection head 50 shown in FIG. 1 will be described in detail with reference to the drawings.

  First, a process (plate formation) for forming the flexible wiring board 26, the common liquid chamber forming plate 25, the piezoelectric element protection plate 24, the vibration plate 23 on which the piezoelectric elements 58 are formed, the pressure chamber forming plate 22, and the nozzle forming plate 21. Processing) will be described with reference to FIG.

  As shown in FIG. 3A, a flexible wiring board 26 is prepared, and bump electrodes 66 made of Au or the like are formed on the flexible wiring board 26. The bump electrode 66 is an electrode to be bonded to the columnar electric wiring 60 of the common liquid chamber forming plate 25 later.

  Further, as shown in FIG. 3B, the common liquid chamber forming plate 25 having the common liquid chamber 55 and the columnar electric wiring 60 is formed. A method for forming the common liquid chamber forming plate 25 is not particularly limited. For example, there is a method in which thin films are stacked while providing necessary openings by photolithography. A plurality of SUS plates may be stacked. One plate may be etched to form a space to be the common liquid chamber 55.

  An insulating protective film 68 is formed on the side surface of the columnar electric wiring 60 by coating. This is to protect the conductive columnar electric wiring 60 from the ink in the common liquid chamber 55.

  Further, as shown in FIG. 3C, the piezoelectric element protection plate 24 is formed. For example, there is a method in which thin films are stacked while providing an opening to be a space for protecting the piezoelectric element 58 by photolithography. A plurality of SUS plates may be stacked. A space for protecting the piezoelectric element 58 may be formed by etching one plate.

  Further, as shown in FIG. 3D, a piezoelectric element 58 is formed on the diaphragm 23. For example, the thin film piezoelectric element 58 is formed on the diaphragm 23 by an AD (aerosol deposition) method or a sputtering method. A bump electrode 64 made of Au or the like is formed on the piezoelectric element 58 in advance. The bump electrode 64 is an electrode to be bonded to the columnar electric wiring 60 of the common liquid chamber forming plate 25 later.

  Further, as shown in FIG. 3E, a pressure chamber forming plate 22 having a pressure chamber 52 is formed. The method for forming the pressure chamber forming plate 22 is not particularly limited. For example, there is a method in which thin films are stacked while providing necessary openings by photolithography. A plurality of SUS plates may be stacked. A space to be the pressure chamber 52 may be formed by etching one plate.

  Further, as shown in FIG. 3F, the nozzle forming plate 21 is formed. A method for forming the nozzle forming plate 21 is not particularly limited, but the nozzle 51 is formed on a plate made of polyimide, for example.

  Next, a process of attaching NCP to the joint part between the plates and the electrical joint part (NCP attachment process) will be described with reference to FIG.

  As shown in FIG. 4A, the NCP 30 is dispensed on the outer end 62 of the columnar electric wiring 60 formed on the common liquid chamber forming plate 25. Specifically, the NCP 30 in the paste state (or liquid state) from the dispensing device 212 is applied to the end 62 on the outside of the columnar electric wiring 60 (which is an electrode to be bonded to the bump electrode 66 of the flexible wiring board 26 later). Is administered. The NCP 30 is administered so as to cover all exposed portions of the end 62 on the outside of the columnar electric wiring 60.

  Further, as shown in FIG. 4B, the NCP 30 is transferred to both joint surfaces of the piezoelectric element protection plate 24 (the joint surface with the common liquid chamber forming plate 25 and the joint surface with the vibration plate 23). . Specifically, the NCP 30 on the sheet 214 is transferred to both joint surfaces by peeling off the sheet 214 coated with NCP after being pressed against both joint surfaces of the piezoelectric element protection plate 24.

  As shown in FIG. 4C, NCP is dispensed onto the bump electrode 64 of the piezoelectric element 58 on the vibration plate 23 and NCP 30 is transferred to the joint surface of the vibration plate 23 with the pressure chamber forming plate 22. Specifically, the NCP 30 in a paste state (or a liquid state) from the dispensing device 212 to the bump electrode 64 on the vibration plate 23 (which is an electrode to be joined to the columnar electric wiring 60 of the common liquid chamber forming plate 25 later). Is administered. The NCP 30 is administered so as to cover all exposed portions of the bump electrode 64 on the diaphragm 23.

  Also, the NCP 30 on the sheet 214 is transferred to the bonding surface by peeling off the sheet 214 coated with NCP after being pressed against the bonding surface of the diaphragm 23 with the pressure chamber forming plate 22.

  Further, as shown in FIG. 4D, the NCP 30 is transferred to the joint surface between the pressure chamber forming plate 22 and the nozzle forming plate 21. Specifically, the NCP 30 on the sheet 214 is transferred to the bonding surface by peeling off the sheet 214 to which the NCP is applied after being pressed against the bonding surface of the pressure chamber forming plate 22 with the nozzle forming plate 21.

  In addition, as an application method of NCP30, a mode in which it is directly administered from the dispensing device 212 to the joining portion and a mode in which NCP30 is attached in advance on the sheet 214 and transferred from the sheet 214 have been described, but screen printing using a mask NCP30 may be applied by the above. Thus, by using NCP30, the choice of the application | coating method increases and the freedom degree of the selection which considered the condition of a coating surface, cost merit, etc. increases.

  Next, the process (NCP hardening process) which hardens NCP of the junction part between plates and an electrical junction part is demonstrated using FIG.

  As shown in FIG. 5, a plurality of plates 21, 22, 23, 24, and 25 are superposed while being positioned and heated under specific curing conditions of NCP in a pressurized state.

  In the example shown in FIG. 5, the flexible wiring boards 26 are also stacked, and the bump electrodes 66 of the flexible wiring boards 26 and the columnar electric wirings 60 are also connected.

  Specifically, the vibration plate 23 (actuator formation plate) in which the nozzle forming plate 21, the pressure chamber forming plate 22, and the piezoelectric element 58 are formed on the base plate 222 having a heating function while being positioned by the positioning pins 226. The piezoelectric element protection plate 24 (intervening plate), the common liquid chamber forming plate 25, and the flexible wiring board 26 are stacked in this order, and a pressure plate 224 having a heating function is placed thereon. The laminated body (laminated structure) from the nozzle forming plate 21 to the flexible wiring board 26 is pressurized by the weight of the pressure plate, and the heating function of the base plate 222 and the pressure plate 224 in such a pressurized state. Thus, heating is performed at the curing temperature of NCP30 for a predetermined time.

  That is, a joint portion between adjacent plates (a joint portion between the nozzle forming plate 21 and the pressure chamber forming plate 22, a joint portion between the pressure chamber forming plate 22 and the vibration plate 23, the vibration plate 23 and the piezoelectric element protection) A bonding portion between the plate 24, a bonding portion between the piezoelectric element protection plate 24 and the common liquid chamber forming plate 25), and an electric bonding portion (the bump electrode 64 of the piezoelectric element 58 and the columnar electric wiring 60). The bonding portion between the bump electrodes 66 of the flexible wiring board 26 and the columnar electric wiring 60) is heated at the curing temperature of the NCP 30 under pressure to bond between the adjacent plates and the electric bonding portion. And simultaneously.

  The curing temperature of NCP30 is desirably a relatively low temperature of 200 ° C. or lower. Thereby, the thermal deformation by a linear expansion difference etc. can be prevented.

  As described above, the case where the flexible wiring board 26 is also pressurized and heated is shown as an example, but only the flexible wiring board 26 may be joined later. That is, after the joining from the nozzle forming plate 21 to the common liquid chamber forming plate 25 is completed, the NCP 30 is dispensed at the joint portion of the bump electrode 66 of the flexible wiring board 26 with the electric wiring 60 as shown in FIG. Then, only the joint portion is cured separately.

  Further, the nozzle forming plate 21 may be joined separately. That is, after the joining from the pressure chamber forming plate 22 to the common liquid chamber forming plate 25 is completed, the NCP 30 is transferred to the joining surface between the nozzle forming plate 21 and the pressure chamber forming plate 22, and only the joining portion is cured. Separately.

  In the present embodiment, the case where the vibration plate 23 and the piezoelectric element protection plate 24 are formed as separate plates has been described as an example. However, the vibration plate 23 and the piezoelectric element protection plate 24 are integrally formed. May be. In this case, the joint surface of the common liquid chamber forming plate 25 and the plate integrally formed with the diaphragm 23 and the pressure chamber protection plate 24 on which the piezoelectric element 58 is formed is bonded by the NCP 30.

[Overall structure of liquid discharge head]
Next, the overall structure of the liquid discharge head will be described.

  FIG. 6 is a plan perspective view showing the entire liquid discharge head 50. In order to increase the density of dots formed on the recording medium, it is necessary to increase the density of nozzles in the liquid ejection head 50. As shown in FIG. 6, the liquid discharge head 50 of this example includes two nozzles 51, which are ink discharge ports, and a plurality of pressure chamber units 54 including pressure chambers 52 and ink supply ports 53 corresponding to the nozzles 51. This has a structure arranged in a dimensional matrix, so that the substantial nozzle interval (projection nozzle pitch) projected so as to be aligned along the longitudinal direction of the liquid discharge head (direction perpendicular to the paper feed direction) Densification has been achieved. In FIG. 6, for convenience of drawing, some pressure chamber units 54 are omitted.

  The detailed structure of each pressure chamber unit 54 and its periphery in FIG. 6 is as described with reference to FIG.

  In FIG. 1, the flow path from the common liquid chamber 55 to the ink supply port 53 of the pressure chamber 52 has an “L” shape, but is drawn as such for convenience of illustration in FIG. 6, the refilling property of the ink from the common liquid chamber 55 to the pressure chamber 52 is given priority, and the “I” shape extends vertically from the common liquid chamber 55 toward the ink supply port 53 of the pressure chamber 52. .

  FIG. 7 is an enlarged view showing a part of the liquid discharge head 50 shown in FIG. As shown in FIG. 7, a large number of pressure chamber units 54 are arranged in a lattice pattern along two directions, ie, a main scanning direction and an oblique direction that forms a predetermined angle θ with respect to the main scanning direction. That is, a large number of nozzles 51 are arranged in a two-dimensional matrix. With such a two-dimensional matrix arrangement, the nozzle density is substantially increased.

  Specifically, a plurality of pressure chamber units 54 are arranged at a constant pitch d along an oblique direction that forms a constant angle θ with respect to the main scanning direction, so that each nozzle 51 extends along the main scanning direction. It can be handled equivalently to those arranged on a straight line with a pitch P (= d × cos θ). Thereby, it is possible to realize a configuration substantially equivalent to a high-density nozzle array of 2400 nozzles per inch (2400 nozzles / inch) along the main scanning direction.

  In implementing the present invention, the nozzle arrangement structure is not limited to the example shown in FIG. Instead of the configuration illustrated in FIG. 6 as a form of a full-line type liquid discharge head having a nozzle row extending in a direction corresponding to the entire width of the recording paper in a direction substantially orthogonal to the recording paper feeding direction, for example, FIG. As shown, a line liquid having a nozzle row having a length corresponding to the entire width of the recording paper is obtained by arranging short liquid discharge head blocks 50 ′ in which a plurality of nozzles 51 are arranged two-dimensionally and connecting them in a staggered manner. An ejection head may be configured.

[Entire configuration of image forming apparatus]
An example of an image forming apparatus to which the above-described liquid discharge head 50 is applied will be described.

  An image forming apparatus 110 shown in FIG. 9 includes a plurality of liquid ejection heads 50K, 50C, 50M provided corresponding to black (K), cyan (C), magenta (M), and yellow (Y) inks. A printing unit 112 having 50Y, an ink storage / loading unit 114 that stores ink to be supplied to each of the liquid ejection heads 50K, 50C, 50M, and 50Y, and a paper feeding unit 118 that supplies recording paper 116 as a recording medium. The decurling unit 120 for removing the curl of the recording paper 116 and the nozzle surface (ink ejection surface) of the printing unit 112 are disposed opposite to each other, and conveys the recording paper 116 while maintaining the flatness of the recording paper 116. , A print detection unit 124 that reads a printing result by the printing unit 112, and a paper discharge unit 126 that discharges recorded recording paper (printed matter) to the outside.

  The ink storage / loading unit 114 includes ink tanks that store inks of colors corresponding to the respective liquid discharge heads 50K, 50C, 50M, and 50Y, and each tank has the liquid discharge heads 50K, 50C via a required pipe line. , 50M, 50Y.

  In FIG. 9, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 118, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  The recording paper 116 delivered from the paper supply unit 118 retains curl due to having been loaded in the magazine. In order to remove the curl, heat is applied to the recording paper 116 by the heating drum 130 in the direction opposite to the curl direction of the magazine in the decurling unit 120.

  In the case of an apparatus configuration using roll paper, a cutter (first cutter) 128 is provided as shown in FIG. 9, and the roll paper is cut to a desired size by the cutter 128. Note that the cutter 128 is not necessary when cut paper is used.

  After the decurling process, the cut recording paper 116 is nipped and transported onto the platen 132 by the transport roller pair 131. A conveying roller pair 133 is also arranged at the subsequent stage of the platen 132 (downstream of the printing unit 112), and the recording sheet 116 is set in a predetermined manner in conjunction with the preceding conveying roller pair 131 and the succeeding conveying roller pair 133. Transport at a speed of.

  The platen 132 functions as a member (recording medium holding means) that holds (supports) the recording paper 116 while maintaining the planarity of the recording paper 116, and also functions as a back electrode. The platen 132 in FIG. 9 has a width that is wider than the width of the recording paper 116, and is configured such that at least the portions facing the nozzle surface of the printing unit 112 and the sensor surface of the printing detection unit 124 form a horizontal plane (flat surface). Has been.

  A heating fan 140 is provided on the upstream side of the printing unit 112 in the conveyance path of the recording paper 116. The heating fan 140 heats the recording paper 116 by blowing heated air onto the recording paper 116 before printing. Heating the recording paper 116 immediately before printing makes it easier for the ink to dry after landing.

  Each of the liquid discharge heads 50K, 50C, 50M, and 50Y of the printing unit 112 has a length corresponding to the maximum paper width of the recording paper 116 targeted by the image forming apparatus 110, and the maximum size recording is performed on the nozzle surface. This is a full-line type liquid discharge head in which a plurality of nozzles for ink discharge are arranged over a length exceeding at least one side of the paper (full width of the drawable range) (see FIG. 6).

  The liquid discharge heads 50K, 50C, 50M, and 50Y are arranged in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side along the feeding direction of the recording paper 116, respectively. The liquid discharge heads 50K, 50C, 50M, and 50Y are fixedly installed so as to extend along a direction substantially orthogonal to the conveyance direction of the recording paper 116.

  A color image can be formed on the recording paper 116 by ejecting different color inks from the respective liquid discharge heads 50K, 50C, 50M, and 50Y while the recording paper 116 is being conveyed by the conveying unit 122.

  As described above, according to the configuration in which the full line type liquid discharge heads 50K, 50C, 50M, and 50Y having nozzle rows covering the entire width of the paper are provided for each color, the recording paper 116 and the recording paper 116 in the paper feeding direction (sub-scanning direction) An image can be recorded on the entire surface of the recording paper 116 by performing the operation of relatively moving the printing unit 112 once (that is, by one sub-scan). Thereby, printing can be performed at higher speed than the shuttle type liquid discharge head in which the recording liquid discharge head reciprocates in the direction orthogonal to the paper conveyance direction, and productivity can be improved.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special color ink are used as necessary. May be added. For example, a configuration in which a liquid discharge head that ejects light-colored ink such as light cyan and light magenta is also possible. Also, the arrangement order of the liquid discharge heads for each color is not particularly limited.

  The print detection unit 124 shown in FIG. 9 includes an image sensor (line sensor or area sensor) for imaging the droplet ejection result of the printing unit 112. From the droplet ejection image read by the image sensor, nozzle clogging or It functions as a means for checking injection failure such as landing position deviation. Test patterns or practical images printed by the liquid ejection heads 50K, 50C, 50M, and 50Y for the respective colors are read by the print detection unit 124, and the print results are inspected.

  A post-drying unit 142 is provided following the print detection unit 124. The post-drying unit 142 is means for drying the printed image surface, and for example, a heating fan is used.

  A heating / pressurizing unit 144 is provided following the post-drying unit 142. The heating / pressurizing unit 144 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 145 having a predetermined uneven surface shape while heating the image surface, and transfers the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 126. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. This image forming apparatus 110 is provided with a sorting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharge units 126A and 126B. Yes. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by the cutter (second cutter) 148. Although not shown in FIG. 9, the paper output unit 126A for the target prints is provided with a sorter for collecting prints according to print orders.

  FIG. 10 is a block diagram illustrating a functional overall configuration example of the image forming apparatus 110. As shown in FIG. 10, the image forming apparatus 110 includes a communication interface 170, a system controller 172, an image memory 174, a ROM 175, a motor driver 176, a heater driver 178, a print control unit 180, an image buffer memory 182 and a head driver 184. I have.

  The communication interface 170 is an image input unit that receives image data sent from the host computer 186. A wired or wireless interface such as USB, IEEE 1394, Ethernet (registered trademark), or a wireless network can be applied to the communication interface 170.

  Image data sent from the host computer 186 is taken into the image forming apparatus 110 via the communication interface 170 and temporarily stored in the image memory 174.

  The system controller 172 includes a central processing unit (CPU) and its peripheral circuits, and controls the entire image forming apparatus 110 according to a predetermined program. That is, the system controller 172 controls the communication interface 170, the image memory 174, the motor driver 176, the heater driver 178, and the like, and performs communication control with the host computer 186, read / write control of the image memory 174 and ROM 175, and the like. At the same time, a control signal for controlling the motor 188 and the heater 189 of the transport system is generated. The transport motor 188 is, for example, a motor that provides power to the drive rollers of the transport roller pairs 131 and 133 described in FIG. The heater 189 is a heating unit used for the heating drum 130, the heating fan 140, the post-drying unit 142, or the like described in FIG.

  The ROM 175 stores programs executed by the CPU of the system controller 172 and various data necessary for control. The ROM 175 may be a non-rewritable storage unit or a rewritable storage unit such as an EEPROM. The image memory 174 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 176 is a driver (driving circuit) that drives the conveyance motor 188 in accordance with an instruction from the system controller 172. The heater driver 178 is a driver that drives the heater 189 in accordance with an instruction from the system controller 172.

  The print control unit 180 functions as a signal processing unit that generates dot data of each color ink based on the input image. That is, the print control unit 180 performs various processes such as processing and correction for generating an ink ejection control signal from the image data in the image memory 174 according to the control of the system controller 172, and generates the generated data (dot data ) To the head driver 184.

  The print control unit 180 includes an image buffer memory 182, and image data, parameters, and other data are temporarily stored in the image buffer memory 182 during image processing in the print control unit 180. In FIG. 10, the image buffer memory 182 is shown in a mode accompanying the print control unit 180, but it can also be used as the image memory 174. Also possible is an aspect in which the print controller 180 and the system controller 172 are integrated and configured with one processor.

  An outline of the processing flow from image input to image formation will be described. Data of an image to be formed is input from the outside via the communication interface 170 and stored in the image memory 174. At this stage, for example, RGB image data is stored in the image memory 174.

  In the image forming apparatus 110, a pseudo continuous tone image is formed by changing the droplet ejection density and dot size of fine dots with ink (coloring material) to the human eye. It is necessary to convert to a dot pattern that reproduces the gradation (shading of the image) as faithfully as possible. Therefore, the original image (RGB) data stored in the image memory 174 is sent to the print control unit 180 via the system controller 172, and the print control unit 180 uses the dither method, the error diffusion method, or the like. Conversion into dot data for each ink color by the conversion process.

  That is, the print control unit 180 performs a process of converting the input RGB image data into dot data of four colors K, C, M, and Y. Thus, the dot data generated by the print control unit 180 is stored in the image buffer memory 182.

  The head driver 184 is for driving the piezoelectric elements 58 corresponding to the nozzles 51 of the liquid ejection head 50 based on the dot data given from the print controller 180 (that is, the dot data stored in the image buffer memory 182). A drive signal is output. The head driver 184 may include a feedback control system for keeping the driving conditions of the liquid ejection head constant.

  When the drive signal output from the head driver 184 is applied to the liquid discharge head 50, ink is discharged from the corresponding nozzle 51. An image is formed on the recording paper 116 by controlling the ink ejection from the liquid ejection head 50 in synchronization with the conveyance speed of the recording paper 116.

  In addition, this invention is not limited to the example demonstrated in embodiment, Of course, in the range which does not deviate from the summary of this invention, various design changes and improvements may be performed.

1 is a cross-sectional view of a liquid ejection head according to an embodiment of the present invention. It is an enlarged view which expands and shows the junction part of columnar electrical wiring and a piezoelectric element. It is explanatory drawing used for description of the process which forms each plate among the manufacturing processes of a liquid discharge head. It is explanatory drawing used for description of the process which adheres NCP among the manufacturing processes of a liquid discharge head. It is explanatory drawing used for description of the process which hardens NCP among the manufacturing processes of a liquid discharge head. 1 is a perspective plan view showing an overall configuration of a liquid ejection head according to an embodiment of the present invention. FIG. 7 is an enlarged view showing a part of the liquid ejection head shown in FIG. 6 in an enlarged manner. It is a plane perspective view which shows the whole structure of the liquid discharge head of another aspect. 1 is an overall configuration diagram of an image forming apparatus to which a liquid ejection head according to an embodiment of the present invention is applied. 1 is a block diagram illustrating a functional configuration of an image forming apparatus to which a liquid ejection head according to an embodiment of the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... Nozzle formation plate, 22 ... Pressure chamber formation plate, 23 ... Vibration plate (actuator formation plate), 24 ... Piezoelectric element protection plate (interposition plate), 25 ... Common liquid chamber formation plate, 26 ... Flexible wiring board (FPC) 30 ... NCP (Non Conductive Paste), 31 ... Inorganic filler, 50 ... Liquid discharge head, 51 ... Nozzle, 52 ... Pressure chamber, 53 ... Ink supply port, 55 ... Common liquid chamber, 58 ... Piezoelectric element (actuator) , 60 ... columnar electric wiring, 64, 66 ... bump electrodes, 110 ... image forming apparatus, 222 ... base plate, 224 ... pressure plate, 226 ... positioning pins

Claims (7)

A flow path plate in which a liquid flow path is formed;
An actuator forming plate on which an actuator for generating pressure when liquid is discharged is formed;
Is formed by laminating a plurality of plates including
An NCP (Non Conductive Paste) having the same curing condition is used for the joint portion between the flow path plate and the actuator forming plate and the electrical joint portion for giving an electric signal to the actuator. A liquid discharge head characterized by being joined. A pressure chamber forming plate in which a pressure chamber communicating with the liquid discharge port is formed;
An actuator forming plate on which an actuator for generating pressure when liquid is discharged is formed;
A common liquid chamber that is disposed on the side opposite to the side on which the pressure chamber forming plate is disposed across the actuator forming plate, and that is substantially perpendicular to the surface on which the actuator is disposed. And a common liquid chamber forming plate in which electrical wiring penetrating at least part of the common liquid chamber is formed,
Is formed by laminating a plurality of plates including
NCP (Non Conductive Paste) in which the joint portion between the actuator forming plate and the common liquid chamber forming plate and the electrical joint portion between the actuator and the electric wiring have the same curing conditions A liquid discharge head characterized by being joined by   The liquid discharge head according to claim 2, wherein the same NCP is used for electrical connection with an FPC (Flexible Print Circuit) that takes out the electrical wiring.   The liquid ejection head according to claim 1, wherein the NCP includes an inorganic filler having a size of 5 μm or less.   An image forming apparatus comprising the liquid discharge head according to claim 1, wherein an image is formed on the recording medium by liquid discharged from the liquid discharge head onto the recording medium. . In the manufacturing method of the liquid discharge head formed by laminating a plurality of plates,
A plurality of plates including a flow path plate in which a liquid flow path is formed and an actuator forming plate in which an actuator that generates pressure when liquid is discharged are prepared, and at least the flow path plate Attaching NCP (Non Conductive Paste) having the same curing condition to a joint portion between the plate and the actuator forming plate and an electrical joint portion for giving an electric signal to the actuator; ,
A step of simultaneously bonding the plate between the flow path plate and the actuator forming plate and bonding of an electric bonding portion for giving an electric signal to the actuator under the curing conditions;
A method for manufacturing a liquid discharge head, comprising: In the manufacturing method of the liquid discharge head formed by laminating a plurality of plates,
A pressure chamber forming plate in which a pressure chamber communicating with the liquid discharge port is formed, an actuator forming plate in which an actuator for generating pressure when liquid is discharged is formed, and the actuator forming plate is sandwiched between At least a part of the common liquid chamber is disposed on the side opposite to the side on which the pressure chamber forming plate is disposed and rises substantially perpendicular to the arrangement surface of the common liquid chamber and the actuator for supplying liquid to the pressure chamber. Preparing a plurality of plates including a common liquid chamber forming plate in which electric wiring penetrating through the plate is formed, at least a joint portion between the actuator forming plate and the common liquid chamber forming plate, and NCP (Non Conductive Paste) having the same curing conditions at the electrical joint between the actuator and the electrical wiring A step of attaching
At least jointing between the actuator forming plate and the common liquid chamber forming plate, and jointing the actuator and the electrical wiring under the curing conditions at the same time;
A method for manufacturing a liquid discharge head, comprising:

Images