JP2011084061A - Liquid ejection head, manufacturing method thereof, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome such a problem that, when a through-hole serving as a pressure generating chamber or a fluid resistance section is formed by a press processing method, a partition shape for dividing the pressure generating chamber is turned into a boat form-shape to become uneven in joining with other member and ejection characteristics vary for each nozzle. <P>SOLUTION: The liquid ejection head includes a flow channel plate 1 on which a plurality of pressure generating chambers 12, a fluid resistance section 13 for supplying a liquid to the pressure generating chamber 12 and a nozzle hole 11 corresponding to the pressure generating chamber 12 are formed from one thin plate. The flow channel plate 1, made of a metal material, includes: the pressure generating chamber 12 formed of a groove-shaped indentation 15; the nozzle hole 11 formed at one end in a longitudinal direction of the groove-shaped indentation 15; and the fluid resistance section 13 formed at the other end in the longitudinal direction of the groove-shaped indentation 15. The pressure generating chamber 12, the nozzle hole 11 and the fluid resistance section 13 are formed by deforming the thin plate in a thickness direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, a manufacturing method thereof, and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. As an apparatus, an ink jet recording apparatus or the like is known. This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid discharge recording method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply It also means that a droplet is landed on a medium). “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials, resins and the like are also included. The “image” is not limited to a planar image (two-dimensional image) but also includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a three-dimensional image itself. .

  The liquid discharge head includes a nozzle plate having a plurality of nozzle holes (also referred to as nozzles, nozzle openings, orifices, discharge ports, etc.) and a pressure generation chamber (pressure chamber, liquid chamber, pressurization) communicating with each nozzle. A liquid chamber, an individual liquid chamber, etc.) and a fluid resistance portion for supplying ink to each pressure generating chamber (also referred to as a chamber plate), a pressure generating chamber and a fluid resistance. A diaphragm member forming a wall surface such as a part is adhesively bonded, and the diaphragm forming the wall surface of the pressure generating chamber is deformed by pressure generating means such as a piezoelectric element to change the volume (volume) in the pressure generating chamber. A device that discharges liquid droplets from a nozzle hole is known (Patent Document 1).

  The nozzle holes of such a liquid discharge head are formed at a pitch of the printing resolution or a pitch of 1/2 to 1/3 thereof, and it is necessary to stabilize the discharged liquid droplets in order to obtain higher quality image quality. Therefore, it is necessary to increase the position accuracy and shape accuracy.

  Conventionally, for example, as a method of manufacturing a nozzle plate, there is known a method of forming a tapered cross-sectional shape by rolling with a punch on a thin metal plate and then polishing and forming a tip portion to become a nozzle hole (patent) Reference 2).

  Moreover, as a manufacturing method of a flow-path board, there exists a method of processing a pressure generation chamber with high precision by anisotropic etching using a silicon single crystal (patent document 3). However, when the size of the head exceeds 1 inch, there is a disadvantage that the material cost increases, and for example, a nozzle plate formed by the above-described processing method and a flow channel plate formed by a silicon material are joined. When curing at a high temperature in order to cure in a short time, the linear expansion coefficients of the materials differ, so that the respective opposing positions shift, warp, and in some cases the silicon material breaks. For this reason, there is a problem that an adhesive that cures at room temperature must be used, and the head manufacturing process takes time.

  Therefore, the flow path plate is formed by forming a through hole in a metal thin plate by an etching method (Patent Document 4) or by forming a pressure generating chamber in an elongated groove by a pressing method (Patent Document 5). It is known to form an ink flow path hole that becomes a pressure generating chamber using a method (Patent Document 6). According to these manufacturing methods, the nozzle plate, the flow path plate, and the diaphragm member can all be formed of the same material, for example, a thin plate made of stainless steel.

  Also, when filling or supplying liquid into the head, if bubbles remain in the nozzle, individual liquid chamber, or common liquid chamber (common flow path) that supplies liquid to a plurality of individual liquid chambers, stable liquid droplet ejection Can no longer do. Further, as the number of nozzles for discharging droplets increases, it is necessary to quickly replenish and supply liquids from the common liquid chamber to the individual liquid chambers. If supply cannot catch up, droplet discharge defects will occur. Become.

  Conventionally, in order to improve the bubble discharge performance in the liquid discharge head, for example, in Patent Document 7, the ceiling part constituting the liquid flow path has a discharge port according to the height from the bottom part constituting the liquid flow path. The region I, the region II, and the region III are formed in this order from the side, the regions I and III are parallel to the bottom surface portion that constitutes the liquid channel, and the region I has a higher liquid channel height than the region III. Has a slope in which the liquid flow path height increases from the region III to the region I, and the region II is formed in a range of distances L1 to L2 from a reference point that is an intersection of the ceiling portion and the discharge port forming surface. The bottom surface portion has discharge pressure generating means in a range of distances LH1 to LH2 from the projection point of the reference point to the bottom surface portion so that the relationship between the ceiling portion and the bottom surface portion satisfies a predetermined relational expression. It is disclosed.

  Further, in Patent Document 8, in a droplet discharge head provided with a piezoelectric element, convex portions extending inward along the longitudinal direction are provided in the vicinity of the edges of the ink inlet and the ink outlet of the pressure chamber. Accordingly, there has been disclosed an apparatus in which the flow rate of ink is increased so that bubbles are easily discharged.

  Further, Patent Document 9 discloses that the stepped portion generated in the flow path is filled with a hardening material and the inner wall of the flow path is smoothed to prevent pressure wave attenuation at the stepped portion and residual bubbles. Yes.

JP-A-7-156387 JP 2002-113529 A JP 2007-144706 A JP 2004-153478 A JP 2000-263799 A JP 2007-152663 A Japanese Patent No. 3495863 JP 2006-205621 A JP 2008-74034 A

  Regarding the above-described flow path plate and the manufacturing method thereof, according to the technique disclosed in Patent Document 4 described above, the pitch of the through holes serving as the pressure generating chamber is roughened to 4 to 5 times the printing resolution, so the head becomes large. However, there is a problem that the image forming apparatus is also increased in size.

  In addition, the technique disclosed in Patent Document 5 includes a first mold having a plurality of convex portions corresponding to the pressure generating chambers and the concave portions serving as ink supply ports, and a plurality of convex portions corresponding to the partition walls between the pressure generating chambers. This is by a so-called forging method in which the second mold is formed by sandwiching a metal thin plate. In this case, it is necessary to form as many uneven portions as the number of nozzles required for the first mold and the second mold. That is, the pitches and shapes of the pressure generating chambers necessary for stabilizing the ejection amount of ink droplets are required for all the uneven portions. Furthermore, in order to form the partition part which divides the pressure generating chamber, it has a structure in which it is raised between the convex parts formed in the first mold, so as a pressing force during press working There is a problem that the cost of the die is increased and the cost of the head is increased.

  An image forming apparatus using an ink jet recording head uses a line type recording head module in which a plurality of heads are arranged in a staggered manner in order to increase the speed. In order to reduce the number of heads when configuring such a head module as much as possible, there is a demand for a highly integrated nozzle and a long head.

  However, in the method using the press working method disclosed in Patent Document 4, in order to lengthen the head, it is necessary to make the first and second molds have the same size as that of the head. This will greatly increase the mold cost. Further, the flow path plate formed by press working needs to include a step of polishing the joint surface before joining the nozzle plate and the vibration plate member, which increases the cost of parts.

  Therefore, as disclosed in Patent Document 6, there is a method of forming a through hole serving as a pressure generating chamber by a press working method. Although the specific processing method is not disclosed in the same document, a positioning hole is formed in the blank plate by press processing, and then a through hole that serves as a pressure generating and fluid resistance portion is formed based on the hole. become.

  In the technique disclosed in Patent Document 6, a mold including a first mold having at least one punch shaped to open a through hole and a second mold having a hole corresponding to the punch. It has a configuration. The chip pushed out by the convex punch of the first mold is pushed into the hole of the second mold. In the back of the hole provided in the second mold, the hole is widened from a position substantially the same as or slightly shorter than the length of the punch of the first mold. Thereby, the pushed-in chip | tip will be discarded through the hole of a 2nd metal mold | die.

  However, the shape of the partition partitioning the pressure generating chamber formed by such a processing method is a boat shape. In the case where the nozzle plate and the diaphragm member are bonded and joined in such a boat-shaped state, twisting may occur in the boat-shaped portion. In particular, in the case of a thin plate having a thickness of several μm such as a diaphragm member, it is easily affected by the shape of the ship shape when being joined, and cannot be joined uniformly. As a result, when the pressure generating means are joined, they are joined non-uniformly, and there arises a problem that the droplet discharge characteristics vary for each nozzle.

  Next, regarding the flow path shape of the flow path plate, in the configuration disclosed in Patent Document 7 described above, an acute angle portion formed by the joint portion of the nozzle plate and the flow path, in the structure disclosed in Patent Document 8 There is a possibility that a narrow portion is generated in a part of the flow path due to its structure, such as a concave portion formed by the liquid chamber wall surface and the convex portion, and on the contrary, there is a possibility that bubbles are retained. Further, in the configuration disclosed in Patent Document 9, it is necessary to fill the curing material after the assembly of the flow path portion, and there is a problem that causes cost increase and manufacturing variation due to process complexity.

  In addition, high-speed printing, high-definition images, and large-format continuous printing are required for the liquid ejection type image forming apparatus, and the size and cost of the apparatus are reduced, and the running cost is low. Higher ones are demanded. In order to meet one or more of these requirements, the nozzle density of the head itself can be increased (for example, 600 to 1200 dpi) and the drive frequency can be increased. Not considered.

  In particular, with a high-density head of 300 dpi or more, it is difficult to ensure the capacity of the liquid chamber itself, and the excluded volume (volume that can exclude liquid from the liquid chamber by displacement of the diaphragm or expansion of bubbles) is very small. For this reason, even bubbles that do not adhere and move in the liquid chamber and do not affect meniscus formation will affect the change in the excluded volume, causing variations in ejection performance. In addition, with a high-density head of 300 dpi or more, there is a problem that the printing speed itself cannot be proportionally increased due to the small excluded volume, so energy loss in the liquid chamber is suppressed, and higher efficiency is achieved. It is necessary to have discharge performance.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable the head to be elongated at low cost.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
From a single thin plate, a plurality of pressure generating chambers, a fluid resistance portion for supplying a liquid to the pressure generating chamber, and a flow path plate in which nozzle holes corresponding to the pressure generating chamber are formed,
The flow path plate is made of a metal material,
The pressure generating chamber formed by a groove-shaped depression;
The nozzle hole formed at one end in the longitudinal direction of the groove-shaped depression;
The fluid resistance portion formed at the other end in the longitudinal direction of the groove-shaped depression,
The pressure generating chamber, the nozzle hole, and the fluid resistance portion are formed by deforming the thin plate in the thickness direction.

  Here, the portion where the nozzle hole is formed may be further deformed toward the droplet discharge direction than the portion where the pressure generating chamber is formed.

  A holding member having a common liquid reservoir for supplying a liquid to the pressure generating chamber through the fluid resistance portion; and the groove-like depression extends to a position facing the common liquid reservoir provided in the holding member, and communicates with the holding member. It can be set as the structure connected with the said common liquid reservoir through the opening | mouth.

  Of the wall surfaces of the flow path from the inlet portion of the communication port to the nozzle hole, the wall surface other than the wall surface on the side where the actuator means for pressurizing the liquid in the pressure generating chamber is always placed on the nozzle surface. On the other hand, it can be set as the structure which is an inclined surface which inclines and changes continuously.

  The image forming apparatus according to the present invention includes the liquid discharge head according to the present invention.

A method for manufacturing a liquid discharge head according to the present invention includes:
A liquid discharge head comprising a plurality of pressure generating chambers, a fluid resistance portion for supplying liquid to the pressure generating chambers, and a flow path plate in which nozzle holes corresponding to the pressure generating chambers are formed from one thin plate. In the manufacturing method,
The thin plate is pressed and deformed in the thickness direction to form the pressure generating chamber composed of a groove-like depression, the fluid resistance portion, and the nozzle opening portion in which the concave portion serving as the nozzle hole is formed, and then the nozzle opening portion The nozzle hole was opened by polishing the tip of the nozzle.

  Here, the groove-like depression formed in the flow path plate can be formed by a half piercing method that stops the pressing process halfway.

  Further, the groove-like depression formed in the flow path plate can be formed by a forging method.

  Further, the pressure generating chamber composed of the groove-like depression, the fluid resistance portion, and the nozzle opening portion may be pressed at the same time.

A first step of pressing a punch having a shape that becomes the pressure generating chamber and the fluid resistance portion on the thin plate;
A second step of pressing a punch for forming the nozzle hole in the thin plate to form a nozzle opening in which a recess to be the nozzle hole is formed;
The third step of opening the nozzle hole by polishing the tip of the nozzle opening formed in the second step, which protrudes from the surface on which the droplets of the thin plate are discharged, can be performed.

  In this case, the first step and the second step can be configured to be a forging method that transfers the punch shape of the pressure generating chamber, the fluid resistance portion, and the nozzle hole.

A first step of pressing a punch having a shape that becomes the pressure generating chamber and the fluid resistance portion on the thin plate;
A second step of polishing the surface protruding to the surface facing the bottom of the groove-shaped depression formed by the pressing;
A third step of pressing a punch for forming the nozzle hole to form a nozzle opening in which a recess to be the nozzle hole is formed;
And a fourth step of opening the nozzle hole by polishing the tip of the nozzle opening formed in the third step.

  In this case, the first step can be configured to be a harp etching in which pressing of the thin plate is stopped halfway by pressing to form a groove recess.

  According to the liquid discharge head according to the present invention, the flow path plate is made of a metal material, is formed with a pressure generating chamber formed by a groove-shaped depression, a nozzle hole formed at one end in the longitudinal direction of the groove-shaped depression, and a groove A fluid resistance portion formed at the other end in the longitudinal direction of the hollow, and the pressure generating chamber, the nozzle hole, and the fluid resistance portion are formed by deforming a thin plate in the thickness direction. The length of the head can be increased at a low cost.

  The image forming apparatus according to the present invention includes the liquid ejection head according to the present invention, so that high speed and low cost can be achieved.

  According to the method for manufacturing a liquid discharge head according to the present invention, a pressure generating chamber formed by pressing a thin plate and deformed in the thickness direction, a pressure generating chamber formed of a groove-like depression, a fluid resistance portion, and a recess serving as a nozzle hole are formed therein. Since the opening is formed and then the tip of the nozzle opening is polished to open the nozzle hole, a long head can be obtained at low cost.

FIG. 3 is a cross-sectional explanatory diagram along a direction orthogonal to a nozzle arrangement direction for explaining the first embodiment of the liquid discharge head according to the present invention. It is a cross-sectional explanatory drawing along a nozzle arrangement direction. FIG. 6 is a cross-sectional explanatory diagram for describing the first embodiment of the method of manufacturing the liquid ejection head according to the present invention. It is explanatory drawing with which it uses for description of the front-end | tip shape of an upper type punch similarly. It is explanatory drawing with which it uses for description of a nozzle hole opening process similarly. FIG. 6 is a cross-sectional explanatory diagram for explaining a second embodiment of the method for manufacturing a liquid ejection head according to the present invention. FIG. 6 is a cross-sectional explanatory diagram along a nozzle arrangement direction for explaining a second embodiment of the liquid ejection head according to the present invention. It is sectional explanatory drawing with which it uses for description of 4th Embodiment of the manufacturing method of the liquid discharge head which concerns on this invention. It is explanatory drawing similarly used for description of a grinding | polishing process. It is explanatory drawing with which it uses for description of the formation process of the opening part for nozzle holes similarly. FIG. 6 is a cross-sectional explanatory diagram along a direction orthogonal to a nozzle arrangement direction for explaining a third embodiment of the liquid ejection head according to the present invention. It is a cross-sectional explanatory drawing along a nozzle arrangement direction. It is a principal part expansion explanatory drawing of FIG. 11 similarly. It is the principal part expansion explanatory drawing of FIG. It is sectional explanatory drawing with which it uses for description of 5th Embodiment of the manufacturing method of the liquid discharge head which concerns on this invention. It is explanatory drawing with which it uses for description of a nozzle hole opening process similarly. It is sectional explanatory drawing with which it uses for description of 6th Embodiment of the manufacturing method of the liquid discharge head which concerns on this invention. FIG. 10 is a cross-sectional explanatory view along the nozzle arrangement direction of a fourth embodiment of the liquid ejection head according to the present invention. It is sectional explanatory drawing with which it uses for description of 8th Embodiment of the manufacturing method of the liquid discharge head which concerns on this invention. FIG. 10 is an explanatory cross-sectional view along a direction orthogonal to a nozzle arrangement direction of a fifth embodiment of a liquid ejection head according to the present invention. 1 is an overall configuration diagram illustrating an example of an image forming apparatus according to the present invention. Similarly it is principal part plane explanatory drawing. It is a schematic block diagram of the whole mechanism part which shows the other example of the image forming apparatus which concerns on this invention. It is explanatory drawing of the recording head of the same apparatus.

Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of a liquid discharge head according to the present invention will be described with reference to FIGS. 1 is a cross-sectional explanatory diagram along a direction orthogonal to the nozzle arrangement direction of the head, and FIG. 2 is a cross-sectional explanatory diagram along the nozzle arrangement direction of the head.
The liquid discharge head 10 includes a flow path unit 3 configured by joining a flow path plate (chamber plate) 1 and a vibration plate member (diaphragm plate) 2, a piezoelectric actuator unit 4 as actuator means, and a frame member 5. Etc.

  The flow path plate 1 supplies a plurality of nozzle holes 11 for discharging droplets, a pressure generation chamber 12 in which each nozzle hole 11 communicates, and the pressure generation chamber 12 from a thin plate made of a single metal material. A fluid resistance portion 13 and an ink introduction portion 14 to the fluid resistance portion 13 are formed. Here, the pressure generating chamber 12 of the flow path plate 1 is formed by a groove-shaped recess 15 formed of a thin plate, and a nozzle hole 11 is formed at one end in the longitudinal direction of the groove-shaped recess 15. A fluid resistance portion 13 is formed on the other end side in the longitudinal direction, and an ink introduction portion 14 is formed on the other end side of the fluid resistance portion 13, and the pressure generating chamber 12, the nozzle hole 11, the fluid resistance portion 13, and the ink introduction portion 14. Is formed by deforming a thin plate in the thickness direction.

  The flow path plate 1 is formed by, for example, a forging press working method. In this case, as shown in FIG. 2, the cross section of the flow path plate 1 has a continuous concave and convex shape, and the concave portion that is the groove-like depression 15 becomes the pressure generating chamber 12, the fluid resistance portion 13, and the ink introducing portion 14, and the convex portion Becomes the respective partition walls 16. The cross-sectional shapes of the pressure generating chamber 12, the fluid resistance portion 13, and the ink introduction portion 14 serving as the ink flow path are trapezoidal rather than quadrangular (this is the case when using a forging method). It is also a feature.)

  The width of the fluid resistance portion 13 is narrower than the width of the pressure generating chamber 12. The depth is shallower than the depth of the pressure generating chamber 12. The depth and width of the fluid resistance portion 13 and the pressure generation chamber 12 may be the same as the pressure generation chamber 12, but by making the width and depth narrower than the pressure generation chamber 12, The ink becomes a resistance portion that tends to return to the ink introduction portion 14 side, and droplets can be discharged more efficiently.

  The position of the nozzle hole 11 is preferably closer to the end of the pressure generating chamber 12. Thereby, when ink is filled in the pressure generation chamber 12, bubbles can be easily removed, and the amount of ink discarded for discharging the bubbles can be reduced and the ejection reliability can be improved. Further, when bubbles are mixed in the pressure generation chamber 12, the bubbles are easily discharged. Further, the groove-like depression 15 extending from the fluid resistance portion 13 extends to the position immediately below the common liquid chamber 18 as the ink introduction portion 14. As a result, the ink can be smoothly introduced from the fluid resistance portion 13 to the pressure generating chamber 12 as described above.

  The diaphragm member 2 forms part of the wall surfaces of the pressure generation chamber 12, the fluid resistance portion 13, and the ink introduction portion 14. The portion of the diaphragm member 2 forming the wall surface of the pressure generation chamber 12 is a deformable region (diaphragm region: diaphragm) 21, and the surface of the diaphragm region 21 on the side opposite to the pressure generation chamber 12 is A convex portion 22 to be joined to the piezoelectric actuator 4 is formed, and the region to be joined to the frame member 5 and the region to be joined to the non-driving piezoelectric element column 52 described later corresponding to the space between the pressure generating chambers 12 and 12 are also thick. A meat part 23 is formed. A portion of the diaphragm member 2 that forms the wall surface of the ink introduction portion 14 has a plurality of penetrations that communicate the common liquid chamber 18 that is a common liquid reservoir formed in the frame member 5 described later and the ink introduction portion 14. A filter portion 25 having a hole 24 is provided.

  The diaphragm member 2 can be formed by, for example, an Ni electroforming method (electroforming method). The thickness of the diaphragm region 21 is, for example, 3 to 7 μm, and the thickness of the convex portion 22 and the thick portion 23 is, for example, 10 to 20 μm. Instead of Ni electroforming, for example, a stainless steel thin plate having a thickness of 5 to 10 μm may be used.

  The piezoelectric actuator 4 is formed by joining one or a plurality of piezoelectric element members 42 on a base member 41, and the piezoelectric element member 42 is divided into a plurality of comb teeth by slit groove processing by half-cut dicing or the like. A piezoelectric element column 51 and a non-driven (dummy) piezoelectric element column 52 are formed. The driving piezoelectric element column 51 is joined to the convex portion 22 of the diaphragm region 21 of the diaphragm member 2, and the non-driving piezoelectric element column 52 is a thick part corresponding to the pressure generation chambers 12, 12 of the diaphragm member 2. 23. Here, as the piezoelectric element member 42, a laminated piezoelectric element member constituted by laminating a conductive material and a piezoelectric material is used and a displacement in the d33 direction is used, but a displacement in the d31 direction is used. Alternatively, a configuration using a bend strain type piezoelectric element in which at least one or more piezoelectric layers are arranged on a flat plate on the vibration plate region 21 of the vibration plate member 2 may be used.

  In addition, although a piezoelectric actuator is used here, a configuration using a thermal actuator or an electrostatic actuator may be used.

  The frame member 5 holds the flow path unit 3 and forms a common liquid chamber 18 for introducing and storing ink from an ink tank (not shown), and the piezoelectric actuator 4 is inserted therein. The frame member 5 is a member having a rigidity several times higher than the rigidity of the flow path unit 3. For example, it is formed by a molding method in which a metal is formed by cutting or a resin is dissolved. The flow path unit 3 and the frame member 5 and the adhesive for bonding them are selected from materials that can withstand enough not to dissolve in the solvent contained in the ink because they are in direct contact with the ink.

  In the liquid ejection head 10 configured in this way, for example, the drive piezoelectric element column 51 contracts by lowering the voltage applied to the drive piezoelectric element column 51 of the piezoelectric element member 42 from the reference potential, and the vibration of the diaphragm member 2 As the plate region 21 is deformed and the volume of the pressure generating chamber 12 expands, the ink flows into the pressure generating chamber 12, and then the voltage applied to the driving piezoelectric element column 51 is increased to drive the driving piezoelectric element column 51. The ink in the pressure generation chamber 12 is pressurized by extending in the stacking direction and deforming the diaphragm region 21 in the direction of the nozzle hole 11 to contract the volume of the pressure generation chamber 12, and ink droplets are discharged from the nozzle hole 11. Discharged.

  Then, by returning the voltage applied to the drive piezoelectric element column 51 to the reference potential, the diaphragm region 21 is restored to the initial position, and the pressure generating chamber 12 expands to generate a negative pressure. At this time, the common liquid chamber From 18, the pressure generating chamber 12 is filled with ink. Therefore, after the vibration of the meniscus surface of the nozzle hole 11 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and striking or pushing can be performed depending on the direction of the drive waveform.

  As described above, in the liquid discharge head 10, a thin plate made of a single metal material is deformed in the thickness direction, and the ink flow path from the fluid resistance portion 13 to the nozzle hole 11 through the pressure generation chamber 12 is integrated. Therefore, the cost can be reduced and the length of the head can be easily increased. In addition, the wall surface in contact with the liquid can be formed as a smooth surface compared to the fractured surface of the flow path hole that forms the pressure generating chamber from the fluid resistance portion that appears by conventional press working, and the ink is smooth (laminar flow) It is possible to improve the bubble discharge performance. Furthermore, it is no longer necessary to join the nozzle plate having the nozzle holes and the flow path plate having the pressure generating chamber with an adhesive or the like, and bubbles are generated due to the inhibition of the ink flow due to the protrusion of the adhesive between the members generated by the joining. It is possible to eliminate the deterioration of the discharge performance or the poor wettability between the adhesive and the ink, and the number of assembling steps can be reduced.

Next, a first embodiment of a method for manufacturing a liquid discharge head according to the present invention for forming a flow path plate of the liquid discharge head according to the first embodiment will be described with reference to FIGS. FIG. 3 is an explanatory diagram for explaining the manufacturing process of the flow path plate in the embodiment, and FIG. 4 is an explanatory diagram for explaining the nozzle hole opening process.
The apparatus for manufacturing the flow path plate includes a first upper mold 60, a second upper mold 65, and a lower mold 70. The first upper mold 60 has a convex portion 62a corresponding to the pressure generation chamber 12 and the fluid resistance portion 13 as shown in FIG. 4 for simultaneously forming the groove 15 which becomes the pressure generation chamber 12 and the fluid resistance portion 13. It has a pressure generating chamber punch 61 having a convex portion 62 composed of a corresponding convex portion 62b, and a stripper 63 that serves as a guide when the punch 61 moves up and down (slides). Note that at least one punch 61 is sufficient. The second upper mold 65 arranged in parallel with the first upper mold 60 includes a nozzle punch 66 having the shape of the nozzle hole 11, and a stripper 67 serving as a guide when the punch 66 moves up and down (slides). have.

  The lower die 70 is formed with an elongated groove 76 that receives the punch 61 of the first upper die 60, and a cylindrical recess 77 for the nozzle hole 11 is provided at the bottom of the groove 76. The die structure has a number corresponding to at least one row of nozzle holes 11.

  Then, as shown in FIG. 3A, one thin plate (hereinafter referred to as “blank material”) 100 made of a metal material installed on the lower mold 70 is fixed by a stripper 63 of the upper mold 60. The From this state, as shown in FIG. 3B, the punch 61 slides downward (gravity direction), and the blank material 100 is pushed into the groove 76 provided in the lower mold 70 by the convex portion 62 of the punch 61. It is. That is, here, press working similar to the so-called drawing method is performed. The process up to this point is the first process, and by this process, the elongated groove-like recess 15 is formed, so that the pressure generating chamber 12 and the fluid resistance portion 13 are simultaneously formed.

  Here, a steel material such as a SUS material can be used as the blank material 100. For example, SUS304H, SUS316L, SUS304-3 / 4H, etc. are suitable because of press workability and versatility. Furthermore, the SUS304H-TA material that has been subjected to the tension annealing treatment is particularly preferable because it is unlikely to be deformed in the heating process in joining the flow path member (nozzle plate liquid chamber integrated member) and the vibration plate member.

  Thereafter, the punch 61 is returned to the original position, is separated from the blank material 100 together with the stripper 62, and is moved to the next press position as shown in FIG. This process is repeated several times, and the groove-shaped depression 15 formed first reaches just below the nozzle hole 11 punch 66 in the second upper mold 65. Here, as shown in FIG. 3D, the nozzle punch 66 of the second upper die 65 is inserted into the groove-like recess 15 formed in the first step until the cylindrical recess 77 of the lower die 70. Pushed in. By this second step, a nozzle opening 102 (see FIG. 5) in which a recess 101 serving as a nozzle opening hole 11 is formed inside is formed on one end side of the groove-like recess 15. Here, the nozzle opening means a portion where the nozzle hole 11 is opened, and has not yet been opened here.

  Thereafter, by repeating the steps shown in FIGS. 3A to 3D described above, the groove 15 and the nozzle opening 102 which are the pressure generating chamber 12 and the fluid resistance portion 13 necessary for the head 10 are formed. The The blank material 100 at this stage is not penetrated as the nozzle hole 11.

  Next, as shown in FIG. 5, the tip of the nozzle opening 102 having the recess 101 that becomes the nozzle hole 11 formed by pressing (the portion shown in FIG. 5 with different hatching) is removed by polishing. To open the nozzle hole 11. This polishing process (nozzle hole opening process) is defined as a third process. In this polishing step, the blank material 100 is fixed by a fixing jig (not shown), and the wrap film 111 is pressed in the direction indicated by the arrow (lightly pressed against the tip of the nozzle opening 102 by the pressing member 112). The nozzle hole 11 is opened by polishing the tip of the nozzle opening 102 while reciprocating in the direction in which the nozzle holes 11 are arranged.

  Through such first to third steps, the flow path plate 1 having the pressure generating chamber 12 having the nozzle hole 11 opened and the fluid resistance portion 13 is obtained. In addition, the blank material 100 (flow-path board 1) formed by such press work becomes a waveform as shown also in FIG.

  Further, although not shown, the joining surface of the flow path plate 1 with the diaphragm member 2 is polished to ensure flatness. Thereby, when joining the piezoelectric actuator 4, it can join uniformly and can reduce the dispersion | variation in the droplet speed between droplet holes and the amount of droplets.

  Then, the flow path plate 1 and the vibration plate member 2 are joined, and the piezoelectric actuator 4 and the frame member 5 are joined to obtain the liquid discharge head 10 described above.

  The clearance between the punch 61 of the upper mold 60 and the corresponding groove 76 of the lower mold 70 is preferably at least larger than the thickness of the blank material 100. This is because the position of the groove portion 76 of the lower die 70 may be relatively rough by simply feeding the upper die 60 with high accuracy, so that the die cost can be reduced. In the case of such a mold configuration, the blank material 100 and the lower mold 70 are fixed, and only the first upper mold 60 and the second upper mold 65 move. The method for fixing the blank material 100 to the lower mold 70 is not particularly limited, and may be such that it is positioned by pins or the like provided on the lower mold 70.

  Also, because the nozzle surface is uneven, when wiping is performed when cleaning the nozzle surface, the ink adhering to the wiper member is wiped off at the convex portion and stored in the concave portion, and the next nozzle is wiped In this case, it is possible to make contact with the cleaned wiper member, and it is easy to remove ink near the nozzle. This also has the effect of preventing foreign matter from adhering to the nozzle portion. In this case, although not shown, an ink suction mechanism is provided so that the ink accumulated in the recess formed on the nozzle surface comes into contact with the recess at the rear end of the groove, for example, at the common liquid chamber 18 side shown in FIG. Can be removed.

Next, a second embodiment of the manufacturing method of the liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the first embodiment will be described with reference to FIG. In addition, FIG. 6 is explanatory drawing with which it uses for description of the manufacturing process of the flow-path board in the embodiment.
Here, the lower mold 70 separates the die 71a and the die 71b so that the die 71b in which the groove portion 76 and the concave portion 77 are formed with respect to the die 71a moves in the vertical direction (arrow direction) in FIG. It has a simple mold configuration. By doing in this way, the upper mold | type 60 and the lower mold | type 70 can be made into a pair of metal mold | die structure completely. Here, it is preferable that the die 71b of the lower die 70 is configured such that the die 71b side is recessed in order to avoid interference with a portion that becomes the pressure generating chamber 12 extruded by the first upper die 60.

  Also in this embodiment, the manufacturing process of the flow path plate 1 is performed in the first to third steps as in the above-described embodiment. That is, first, in the first step, as shown in FIG. 6B from the state of FIG. 6A, the elongated groove-like recess 15 that becomes the pressure generation chamber 12 and the fluid resistance portion 13 is formed by the first upper mold 60. Form. Next, as shown in FIG. 6C, the first upper mold 60 slides upward, and the second upper mold 65 moves to a position facing the die 72 of the lower mold 70. In the second step, as shown in FIG. 6D, the nozzle punch 66 moves downward and is pushed into the recess 77 provided in the groove 76 of the die 72 of the lower mold 70. As a result, a nozzle opening 102 in which a recess that becomes the nozzle hole 11 is formed is formed. By repeating this operation continuously, the blank material 100 before the nozzle hole 11 penetrates can be manufactured.

  Thereafter, similarly to the first embodiment, the nozzle hole 11 of the nozzle opening 102 is opened in the polishing process.

  By using the mold configuration as in this embodiment, the entire mold can be reduced in size.

Next, a third embodiment of the method for manufacturing a liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the first embodiment will be described.
In the first and second embodiments described above, the groove-like recess 15 that becomes the pressure generating chamber 12 is formed prior to the step of forming the nozzle opening 102 for the nozzle hole 11, but in this case, the nozzle The stroke amount for pushing the hole punch 66 becomes longer.

  Accordingly, in the third embodiment, the nozzle hole punching process, which is the second process of the first and second embodiments, for example, the process shown in FIGS. 3C and 6C, is performed as the first process. The nozzle opening 102 corresponding to the necessary nozzle hole 11 is formed first. Next, as a second step, the nozzle hole 11 is opened by polishing the tip of the nozzle opening 102 previously formed by the punch 66 as described in FIG. By this polishing process, the blank material 100 becomes a flat plate again. Then, as a final third step, a groove-like recess 15 that becomes the pressure generation chamber 12 and the fluid resistance portion 13 is formed (for example, the steps of FIG. 3D and FIG. 6D). In this case, an upper mold and a lower mold in the first process and a pair of the upper mold and the lower mold in the second process are provided for exclusive use.

Next, a second embodiment of the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 7 is an explanatory sectional view taken along the nozzle arrangement direction of the head.
The flow path plate 1 of the liquid discharge head is formed by a half piercing method which is one of press processing methods. That is, after forming the pressure generating chamber 12, the nozzle hole 11 is formed by a forging method. In this case, the pressure generating chamber 12 has a substantially square cross section, and the surface of the nozzle hole 11 can be made substantially flat. Even if comprised in this way, the effect similar to the said 1st Embodiment can be acquired.

Next, a fourth embodiment of the manufacturing method of the liquid discharge head of the present invention for forming the flow path plate of the liquid discharge head according to the second embodiment will be described with reference to FIGS.
First, the manufacturing apparatus has a first upper mold 80 and a lower mold 90. The first upper die 80 includes a pressure generating chamber punch 81 having a convex portion 82 for simultaneously forming the pressure generating chamber 12 and the groove-like recess 15 that becomes the fluid resistance portion 13, and the punch 81 slides up and down. And a stripper 83 serving as a guide. Note that at least one punch 81 is sufficient. The lower mold 90 has a die structure having at least the same number of recesses 96 that receive the punch 81 as the nozzle holes 11 of the head. The recess 96 has an elongated groove shape.

  Then, as shown in FIG. 8A, the blank material 110 installed on the lower mold 90 is fixed by the stripper 83 of the upper mold 80. From this state, the punch 81 slides downward, and the blank material 100 is pushed into the recess 96 provided in the lower mold 90 as shown in FIG. At this time, the pressing of the punch 81 is stopped at a position where the amount to be pressed is smaller than the thickness of the blank material 100. Further, unlike the first embodiment, the clearance between the punch 81 and the recess 96 is equal to or less than the plate thickness, for example, a gap of about 3 μm. The process up to here is referred to as a first process, and by this first process, the elongated groove-like recess 15 that becomes the pressure generating chamber 12 and the fluid resistance portion 13 is simultaneously formed.

  Thereafter, the punch 81 is returned, moves away from the blank material 110 together with the stripper 82, moves to the next press position as shown in FIG. 8C, and the punch 81 is pushed in again. By repeating the press processing from FIG. 8A to FIG. 8C, a groove-like recess 15 that forms the pressure generating chamber 12 and the fluid resistance portion 13 necessary for the head is formed. The blank material 110 in this state is in a state in which a concave portion (groove-shaped depression 15) on the pressure generating chamber 12 side and a convex portion 103 that becomes the surface of the nozzle hole 11 are formed, and the nozzle hole 11 is not formed. Absent.

  Next, only the concave portion (groove-like depression 15) formed by the above-described press working and the convex portion 103a (the portion protruding from the surface of the blank material 110) of the convex portion 103 are polished. The polishing method is the same as the method shown in FIG. 5, and its outline is shown in FIG. That is, the wrap film 111 is brought into contact with the surface of the convex portion 103a of the blank material 100 processed by the press processing. At this time, the wrap film 111 is lightly pressed by the pressing member 112 and polished while reciprocating in the row direction of the nozzle holes 11 (arrow direction in the drawing). Thereby, the surface of the nozzle hole 11 to be processed in the next step is finished almost flat. This step is referred to as the second step.

  Through this process, a thin portion 104 corresponding to the pressure generation chamber 12 shown in FIG. 9B is formed, and a blank material 110 in which members corresponding to the nozzle plate are integrated is obtained.

  Next, the thin-walled portion 104 is formed with a projection that becomes the nozzle hole 11 by a pressing technique using a forging method. As shown in FIG. 10, processing is performed in a manner similar to that of FIGS. 6C and 6D described above, using a nozzle 61 for punching a nozzle hole and a lower die 91 having a die 92 a and a die 92 b having a groove 97. Can do. This is the third step. Thereafter, the flow path plate 1 in which the nozzle holes 11 are integrally formed with the pressure generating chamber 12 is obtained by a fourth step of polishing the protrusions by the method shown in FIG.

Next, a third embodiment of the liquid ejection head according to the present invention will be described with reference to FIGS. 11 is a cross-sectional explanatory diagram along a direction orthogonal to the nozzle arrangement direction of the head, and FIG. 12 is a cross-sectional explanatory diagram along the nozzle arrangement direction of the head.
In the present embodiment, a flow path plate having a groove-shaped recess 115 having a shape different from the groove-shaped recess 15 of the flow path plate in each of the above embodiments is used. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  That is, the channel plate 1 is an individual channel in which each nozzle hole 11 communicates with a plurality of nozzle holes 11 for discharging droplets from a single thin plate made of a metal material, as in the above embodiments. A pressure generation chamber 12, a fluid resistance portion 13 that supplies ink to the pressure generation chamber 12, and an ink introduction portion 14 to the fluid resistance portion 13 are formed.

  Here, the pressure generation chamber 12 of the flow path plate 1 is formed by a groove-like recess 115 formed of a thin plate, and a nozzle hole 11 is formed at one end in the longitudinal direction of the groove-like recess 115, so that the groove-like recess 115 A fluid resistance portion 13 is formed on the other end side in the longitudinal direction, and an ink introduction portion 14 is formed on the other end side of the fluid resistance portion 13, and the pressure generating chamber 12, the nozzle hole 11, the fluid resistance portion 13, and the ink introduction portion 14. Is formed by deforming a thin plate in the thickness direction.

  The flow path plate 1 is formed by, for example, a forging press working method, and the cross section of the flow path plate 1 has a continuous concavo-convex shape as shown in FIG. The fluid resistance portion 13 and the ink introduction portion 14 are formed, and the convex portions are the respective partition walls 16.

  As shown in FIGS. 13 and 14, the flow path plate 1 includes an actuator among the wall surfaces of the flow path from the ink introduction path 14 that is the inlet portion of the supply path (flow path) to the nozzle hole 11. Wall surfaces 31a to 31d other than the wall surface on the side where the means is arranged, that is, the wall surface formed by the diaphragm member 2, are inclined surfaces that always have an inclination with respect to the nozzle surface 11a and continuously change. That is, the flow path plate 1 has a tangential direction of the wall surface always inclined with respect to the nozzle surface 11a from the supply port for supplying ink to the liquid chamber 12 to the nozzle hole 11, and is continuous without being parallel to the nozzle surface 11a. The shape gradually changes.

  As described above, the wall surface on the side where the actuator means is arranged among the wall surfaces of the flow path from the ink introduction path 14 to the nozzle hole 11 is always inclined with respect to the nozzle surface 11a and continuously changes. Therefore, it is rich in bubble discharge properties and ink retention is less likely to occur. In addition, since there is no opposing surface that obstructs the ink flow, and the liquid chamber shape is constricted in the nozzle surface direction, the ink flow can be concentrated on the nozzle, energy loss is suppressed, and highly efficient droplets are suppressed. Discharging can be performed.

  In this case, in particular, the relationship of the distance L between the cross-sectional areas S1, S2, and S1-S2 in FIG. 13 is (S2-S1) /L≦0.18 to prevent ink stagnation and improve bubble discharge performance. It was confirmed as a result of the experiment that this is preferable.

Next, a fifth embodiment of the method for manufacturing a liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the third embodiment will be described with reference to FIGS. 15 is a cross-sectional explanatory view for explaining the manufacturing process of the flow path plate in the embodiment, and FIG. 16 is a cross-sectional explanatory view for explaining the nozzle hole opening step.
The apparatus for manufacturing the flow path plate includes a first upper mold 160, a second upper mold 165, and a lower mold 170. The first upper mold 160 includes a pressure generating chamber punch 161 having a convex portion 162 for simultaneously forming the pressure generating chamber 12 and the groove-like recess 115 to be the fluid resistance portion 13, and the punch 161 moves up and down ( And a stripper 163 serving as a guide when sliding). Note that at least one punch 161 is sufficient. The second upper mold 165 arranged in parallel with the first upper mold 160 includes a nozzle punch 166 having the shape of the nozzle hole 11, and a stripper 167 serving as a guide when the punch 166 moves (slides) up and down. have.

  Here, the shape of the convex portion 162 of the punch 161 of the first upper mold 160 and the tip shape of the punch 166 of the second upper mold 165 are determined from the ink introduction path 14 which is the inlet portion of the supply path (flow path) to the nozzle hole 11. Of the wall surface of the flow path leading to the nozzle surface 11a, a shape that forms an inclined surface that continuously changes toward the nozzle surface 11a, that is, the wall surface from the supply port for supplying ink to the pressure generating chamber 12 to the nozzle hole 11 The tangential direction is always inclined with respect to the nozzle surface 11a, and is formed in a shape that continuously and gently changes without being parallel to the nozzle surface 11a.

  The lower mold 170 is formed with an elongated groove 176 for receiving the punch 161 of the first upper mold 160, and a cylindrical recess 177 for the nozzle hole 11 is provided at the bottom of the groove 176, and the groove 176 is formed on the head. The die structure has a number corresponding to at least one row of nozzle holes 11.

  Then, as shown in FIG. 15A, one thin plate (hereinafter referred to as “blank material”) 150 made of a metal material installed on the lower mold 170 is fixed by a stripper 163 of the upper mold 160. The From this state, as shown in FIG. 15B, the punch 161 slides downward (gravity direction), and the blank material 150 is pushed into the groove 176 provided in the lower mold 170 by the convex portion 162 of the punch 161. It is. That is, here, press working similar to the so-called drawing method is performed. The process up to this point is the first process, and by this process, the elongated groove-like depression 115 is formed, so that the pressure generating chamber 12, the fluid resistance part 13, and the nozzle introduction part 114 are simultaneously formed.

  After that, the punch 161 is returned to the original position, separated from the blank material 150 together with the stripper 162, and moved to the next press position as shown in FIG. This process is repeated several times, and the groove-shaped recess 115 formed first reaches just below the nozzle hole 11 punch 166 in the second upper die 165. Here, as shown in FIG. 15 (d), the nozzle punch 166 of the second upper mold 165 is inserted into the groove-shaped recess 115 formed in the first step until the cylindrical recess 177 of the lower mold 170. Pushed in. By this second step, a nozzle opening 152 (see FIG. 16) in which a recess 151 that becomes the nozzle hole 11 is formed inside is formed on one end side of the groove-like recess 115. Here, the nozzle opening means a portion where the nozzle hole 11 is opened.

  Thereafter, by repeating the steps shown in FIGS. 15A to 15D, the pressure generating chamber 12 required for the head, the fluid resistance portion 13, and the groove-like recess 115 serving as the ink introduction portion 114, and the nozzle opening portion. 152 is formed. The blank material 150 at this stage is not penetrated as the nozzle hole 11.

  Next, as shown in FIG. 16, the tip of the nozzle opening 152 having a recess 151 that becomes the nozzle hole 11 formed by pressing (the portion shown in FIG. 16 with different hatching) is removed by polishing. To open the nozzle hole 11. This polishing process (nozzle hole opening process) is defined as a third process. In this polishing step, the blank material 150 is fixed by a fixing jig (not shown), and the wrap film 155 is pressed in the direction indicated by the arrow while the polishing wrap film 155 is lightly pressed against the tip of the nozzle opening 152 by the pressing member 152. The nozzle hole 11 is opened by polishing the tip of the nozzle opening 152 while reciprocating in the direction in which the nozzle holes 11 are arranged.

  Through such first to third steps, the flow path plate 1 having the pressure generating chamber 12 having the nozzle hole 11 opened and the fluid resistance portion 13 is obtained. In addition, the blank material 150 (flow-path board 1) formed by such press work becomes a waveform as shown also in FIG.

  Further, although not shown, the joining surface of the flow path plate 1 with the diaphragm member 2 is polished to ensure flatness. Thereby, when joining the piezoelectric actuator 4, it can join uniformly and can reduce the dispersion | variation in the droplet speed between droplet holes and the amount of droplets.

  Then, the flow path plate 1 and the vibration plate member 2 are joined, and the piezoelectric actuator 4 and the frame member 5 are joined to obtain the liquid discharge head described above.

  The clearance between the punch 161 of the upper mold 160 and the corresponding groove 176 of the lower mold 170 is preferably at least larger than the plate thickness of the blank material 150. This is because the position of the groove 176 of the lower die 170 may be relatively rough by simply feeding only the feeding accuracy of the upper die 160 with high accuracy, so that the die cost can be reduced. In the case of such a mold configuration, the blank material 150 and the lower mold 170 are fixed, and only the first upper mold 160 and the second upper mold 165 move. The method for fixing the blank material 150 to the lower mold 170 is not particularly limited, and may be such that the blank material 150 is positioned by a pin or the like provided on the lower mold 170.

Next, a sixth embodiment of the manufacturing method of the liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the third embodiment will be described with reference to FIG. In addition, FIG. 17 is sectional explanatory drawing with which it uses for description of the manufacturing process of the flow-path board in the same embodiment.
Here, a die 172 having a groove 176 and a recess 177 is movably disposed in the lower mold 170 so that the upper mold 160, 165 and the lower mold 170 are a pair of mold structures. The size is reduced.

  Also in this embodiment, the manufacturing process of the flow path plate 1 is performed in the first to third processes as in the fifth embodiment described above. That is, first, in the first step, as shown in FIG. 17B from the state of FIG. 17A, the upper mold 160 serves as the pressure generating chamber 12, the fluid resistance portion 13, and the ink introduction portion 14. A recess 115 is formed. Next, as shown in FIG. 17C, the first upper mold 160 slides upward, and the second upper mold 165 moves to a position facing the die 172 of the lower mold 170. In the second step, as shown in FIG. 17D, the nozzle punch 166 moves downward and is pushed into the recess 177 provided in the groove 176 of the die 172 of the lower mold 170. As a result, a nozzle opening 152 in which a recess that becomes the nozzle hole 11 is formed is formed. By repeating this operation continuously, the blank material 150 before the nozzle hole 11 penetrates can be manufactured.

  Thereafter, as in the fifth embodiment, the nozzle holes 11 of the nozzle openings 102 are opened in the polishing process.

Next, a description will be given of a seventh embodiment of the method for manufacturing a liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the third embodiment.
In the fifth and sixth embodiments described above, the groove-like depression 115 that becomes the pressure generating chamber 12 is formed prior to the step of forming the nozzle opening 152 for the nozzle hole 11. The stroke amount for pushing the hole punch 166 becomes longer.

  Therefore, in the sixth embodiment, the nozzle hole punching process, which is the second process of the fifth and sixth embodiments, for example, the process shown in FIGS. 15D and 17D, is performed as the first process. The nozzle opening 152 corresponding to the necessary nozzle hole 11 is formed first. Next, as described in FIG. 16, the nozzle hole 11 is opened by polishing the tip of the nozzle opening 152 previously formed by the punch 166 as described in FIG. 16. By this polishing process, the blank material 150 becomes a flat plate again. Then, as a final third step, a groove-like recess 115 that becomes the pressure generation chamber 12 and the fluid resistance portion 13 is formed (for example, the steps of FIGS. 15B and 17B). In this case, an upper mold and a lower mold in the first process and a pair of the upper mold and the lower mold in the second process are provided for exclusive use.

Next, a fourth embodiment of the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 18 is a cross-sectional explanatory view along the nozzle arrangement direction of the head.
The flow path plate 1 of the liquid discharge head is formed by a half piercing method which is one of press processing methods. That is, after forming the pressure generating chamber 12, the nozzle hole 11 is formed by a forging method. Even if comprised in this way, the effect similar to the said 1st Embodiment can be acquired.

Next, an eighth embodiment of the method for manufacturing a liquid discharge head according to the present invention for forming the flow path plate of the liquid discharge head according to the fourth embodiment will be described with reference to FIG. In addition, FIG. 19 is sectional explanatory drawing explaining the manufacturing process of the flow-path board in the embodiment.
First, the manufacturing apparatus has a first upper mold 180 and a lower mold 190. The first upper mold 180 includes a pressure generating chamber punch 181 having a convex portion 182 for simultaneously forming a groove-like recess 115 that becomes the pressure generating chamber 12 and the fluid resistance portion 13, and the punch 181 slides up and down. It has a stripper 183 that serves as a guide at times. Note that at least one punch 181 is sufficient. The lower mold 190 has a die structure having at least as many concave portions 196 that receive the punches 181 as the nozzle holes 11 of the head. The recess 196 has an elongated groove shape. Further, as described above, the shape of the convex portion 182 of the punch 181 is formed on the nozzle surface 11a in the wall surface of the flow path from the ink introduction path 114, which is the inlet portion of the supply path (flow path), to the nozzle hole 11. The shape that forms an inclined surface that continuously changes toward the nozzle, that is, the tangential direction of the wall surface from the supply port for supplying ink to the pressure generating chamber 12 to the nozzle hole 11 is always inclined with respect to the nozzle surface 11a. The shape is formed in a shape that continuously and gently changes without being parallel to the nozzle surface 11a.

  Then, as shown in FIG. 19A, the blank material 150 (thickness is thicker than that of the fourth embodiment) installed on the lower mold 190 is fixed by the stripper 183 of the upper mold 180. From this state, the punch 181 slides downward, and the blank material 150 is pushed into the recess 196 provided in the lower mold 190 as shown in FIG. At this time, the pressing of the punch 181 is stopped at a position where the amount to be pressed is smaller than the thickness of the blank material 150. Further, unlike the fourth embodiment, the clearance between the punch 181 and the recess 196 is equal to or less than the plate thickness, for example, a gap of about 3 μm. The process up to here is referred to as a first process, and by this first process, an elongated groove-like recess 115 serving as the pressure generating chamber 12 and the fluid resistance portion 13 is simultaneously formed.

  Thereafter, the punch 181 is returned, moves away from the blank material 150 together with the stripper 182, moves to the next press position, as shown in FIG. 19C, and the punch 181 is pushed in again. By repeating the press processing from FIG. 19A to FIG. 19C, a groove-like recess 115 forming the pressure generating chamber 12 and the fluid resistance portion 13 necessary for the head is formed. The blank material 150 in this state is in a state in which a concave portion (groove-shaped depression 115) on the pressure generation chamber 12 side and a convex portion 153 that becomes the surface of the nozzle hole 11 are formed, and the nozzle hole 11 is not formed. Absent.

  Next, only the convex portion 153 of the concave portion (groove-shaped depression 115) and the convex portion 153 formed by the above-described press working is polished to finish the surface on which the nozzle hole 11 is formed substantially flat. This step is referred to as the second step. By this step, as shown in FIG. 19D, a thin portion 154 corresponding to the pressure generating chamber 12 is formed, and a portion corresponding to the nozzle plate is formed integrally with the flow path plate 101. Therefore, a nozzle opening for forming the nozzle hole 11 is formed in the thin portion 154 by a pressing technique using a forging method. Here, although not shown, for example, it can be processed by a method similar to that shown in FIG. This is the third step. Thereafter, the flow path plate 101 in which the nozzle holes 11 are formed integrally with the pressure generation chamber 12 is obtained by the fourth step of polishing the protrusions by the method shown in FIG.

Next, a fifth embodiment of the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 20 is a cross-sectional explanatory diagram along a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head.
This liquid discharge head has two nozzle holes 11 arranged, and the other configuration can be any of the configurations of the above-described embodiment, and thus the description thereof is omitted.

Next, an example of the image forming apparatus according to the present invention including the liquid discharge head according to the present invention will be described with reference to FIGS. FIG. 21 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG. 22 is a plan view of a principal portion of the mechanism portion.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in a main scanning direction by main and sub guide rods 231 and 232 which are guide members horizontally mounted on left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 is supplied with ink supplied to the same head as the liquid discharge head according to the present invention for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). A recording head 234 composed of a liquid ejection head unit with an integrated tank is arranged in a sub-scanning direction perpendicular to the main scanning direction with a nozzle row composed of a plurality of nozzles, and mounted with the ink droplet ejection direction facing downward. Yes.

  The recording head 234 is configured by attaching liquid discharge head units 234a and 234b each having two nozzle rows to one base member, and one nozzle row of one head 234a receives black (K) droplets. The other nozzle row ejects cyan (C) droplets, the other nozzle row of the other head 234b ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets. To do. Here, a configuration in which droplets of four colors are ejected in a two-head configuration is used, but it is also possible to arrange four nozzle rows per head and eject each of the four colors with one head.

  Further, the ink of each color is replenished and supplied from the ink cartridge 210 of each color to the tank 235 of the recording head 234 via the supply tube 236 of each color.

  On the other hand, as a paper feed unit for feeding the paper 242 loaded on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feed) that feeds the paper 242 from the paper stacking unit 241 one by one. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 including a recovery means for maintaining and recovering the nozzle state of the recording head 234 is disposed in the non-printing area on one side in the scanning direction of the carriage 233. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets for discharging the liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing.

  Further, in the non-printing area on the other side in the scanning direction of the carriage 233, there is an empty space for receiving a liquid droplet when performing an empty discharge for discharging a liquid droplet that does not contribute to the recording in order to discharge the recording liquid thickened during the recording. A discharge receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressing roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  As described above, the image forming apparatus includes the liquid discharge head according to the present invention as a recording head, so that the cost can be reduced and the speed can be increased by increasing the length of the head.

Next, another example of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention will be described with reference to FIG. FIG. 23 is a schematic configuration diagram of the entire mechanism unit of the apparatus.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 402 and the like inside the apparatus main body 401, and can supply a large number of recording media (sheets) 403 on the lower side of the apparatus main body 401. A paper tray 404 is provided, a sheet 403 fed from the sheet feeding tray 404 is taken in, a required image is recorded by the image forming unit 402 while the sheet 403 is conveyed by the conveying mechanism 405, and then the side of the apparatus main body 401. The paper 403 is discharged to a paper discharge tray 406 attached to the printer.

  Also, a duplex unit 407 that can be attached to and detached from the apparatus main body 401 is provided, and when performing duplex printing, the sheet 403 is conveyed into the duplex unit 407 while being transported in the reverse direction by the transport mechanism 405 after one-side (front) printing is completed. Then, the other side (back side) is sent back to the transport mechanism 405 as the printable side, and the paper 403 is discharged to the paper discharge tray 406 after the other side (back side) printing is completed.

  Here, the image forming unit 402 ejects liquid droplets of each color of yellow (Y), magenta (M), cyan (C), and black (K), for example, four line type liquid ejection according to the present invention. The recording heads 411y, 411m, 411c, and 411k (referred to as “recording heads 411” when colors are not distinguished) are configured by integrating a head and a sub tank that supplies ink to the liquid discharge head. The head holder 413 is mounted with the nozzle surface on which the nozzle for discharging droplets is formed facing downward.

  As shown in FIG. 24, one recording head 411 has a plurality (six in this example) of sub-tank integrated liquid discharge heads 501A to 501F according to the present invention arranged on the base member 502 in a predetermined positional relationship. However, it can also be constituted by one full line type liquid discharge head.

  In addition, a maintenance / recovery mechanism 412y, 412m, 412c, 412k (referred to as “maintenance / recovery mechanism 412” when colors are not distinguished) corresponding to each recording head 411 is provided to maintain and recover the performance of the head. During the head performance maintenance operation such as wiping processing, the recording head 411 and the maintenance / recovery mechanism 412 are relatively moved so that the capping member constituting the maintenance / recovery mechanism 412 faces the nozzle surface of the recording head 411.

  The paper 403 in the paper feed tray 404 is separated one by one by a paper feed roller (half-moon roller) 421 and a separation pad (not shown) and fed into the apparatus main body 401, and is registered along the guide surface 423 a of the transport guide member 423. It is sent between 425 and the conveyor belt 433, and is sent to the conveyor belt 433 of the conveyor mechanism 405 via the guide member 426 at a predetermined timing.

  The conveyance guide member 443 is also formed with a guide surface 423 b for guiding the paper 403 sent out from the duplex unit 407. Further, a guide member 427 for guiding the sheet 403 returned from the transport mechanism 405 to the duplex unit 407 during duplex printing is also provided.

  The conveyance mechanism 405 includes an endless conveyance belt 433 that is stretched between a conveyance roller 431 that is a driving roller and a driven roller 432, a charging roller 434 that charges the conveyance belt 433, and an image forming unit 402. A platen member 435 that maintains the flatness of the conveyance belt 433 at the opposite portion, a pressing roller 436 that presses the paper 403 fed from the conveyance belt 433 against the conveyance roller 431 side, and other recording liquid that is attached to the conveyance belt 433, although not shown. It has a cleaning roller made of a porous material or the like, which is a cleaning means for removing (ink). As the transport mechanism, for example, a mechanism that sucks the recording medium onto the transport belt by air suction can be used.

  On the downstream side of the transport mechanism 405, a paper discharge roller 438 and a spur 439 for sending the paper 403 on which an image is recorded to the paper discharge tray 406 are provided.

  In the image forming apparatus configured as described above, the conveyance belt 433 moves in the direction indicated by the arrow and is charged by contact with the charging roller 434 to which a high applied voltage is applied. When 403 is fed, the sheet 403 is electrostatically attracted to the conveyance belt 433. In this way, the sheet 403 that is strongly adsorbed to the transport belt 433 is calibrated for warpage and unevenness, and forms a highly flat surface.

  Then, the paper 403 is moved around the conveyor belt 433 and droplets are ejected from the recording head 411, whereby a required image is formed on the paper 403, and the paper 403 on which the image has been recorded is the paper discharge roller 438. As a result, the paper is discharged to the paper discharge tray 406.

  As described above, since the image forming apparatus includes the liquid discharge head according to the present invention, it is possible to reduce the cost and increase the speed.

  In the above-described embodiment, the present invention has been described with reference to an example in which the present invention is applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. In addition, as described above, the present invention can also be applied to an image forming apparatus using a liquid other than the narrowly defined ink or a fixing processing liquid.

DESCRIPTION OF SYMBOLS 1 Flow path plate 2 Vibration plate member 3 Flow path unit 4 Piezoelectric actuator 5 Frame member 11 Nozzle hole 12 Pressure generating chamber 13 Fluid resistance part 14 Ink introduction part 15, 115 Groove-shaped depression 18 Common liquid chamber (common liquid reservoir)
41 Base member 42 Piezoelectric element member 51 Drive piezoelectric element column 233 Carriage 234a, 234b Recording head 411y, 411m, 411c, 411k Recording head

Claims (13)

From a single thin plate, a plurality of pressure generating chambers, a fluid resistance portion for supplying a liquid to the pressure generating chamber, and a flow path plate in which nozzle holes corresponding to the pressure generating chamber are formed,
The flow path plate is made of a metal material,
The pressure generating chamber formed by a groove-shaped depression;
The nozzle hole formed at one end in the longitudinal direction of the groove-shaped depression;
The fluid resistance portion formed at the other end in the longitudinal direction of the groove-shaped depression,
The liquid ejection head, wherein the pressure generating chamber, the nozzle hole, and the fluid resistance portion are formed by deforming the thin plate in a thickness direction.   The liquid discharge head according to claim 1, wherein the portion where the nozzle hole is formed is further deformed toward the droplet discharge direction side than the portion where the pressure generating chamber is formed.   A holding member having a common liquid reservoir for supplying a liquid to the pressure generating chamber through the fluid resistance portion; and the groove-like recess extends to a position facing the common liquid reservoir provided in the holding member, and has a communication port. The liquid discharge head according to claim 1, wherein the liquid discharge head is connected to the common liquid reservoir.   Of the wall surfaces of the flow path from the inlet portion of the communication port to the nozzle hole, the wall surfaces other than the wall surface on the side where the actuator means for pressurizing the liquid in the pressure generating chamber is always disposed with respect to the nozzle surface. The liquid discharge head according to claim 1, wherein the liquid discharge head is an inclined surface having an inclination and continuously changing.   An image forming apparatus comprising the liquid discharge head according to claim 1. A liquid discharge head comprising a plurality of pressure generating chambers, a fluid resistance portion for supplying liquid to the pressure generating chambers, and a flow path plate in which nozzle holes corresponding to the pressure generating chambers are formed from one thin plate. In the manufacturing method,
The thin plate is pressed and deformed in the thickness direction to form the pressure generating chamber composed of a groove-like depression, the fluid resistance portion, and the nozzle opening portion in which the concave portion serving as the nozzle hole is formed, and then the nozzle opening portion A method of manufacturing a liquid discharge head, wherein the nozzle hole is opened by polishing the tip of the liquid.   The method for manufacturing a liquid discharge head according to claim 6, wherein the groove-shaped depression formed in the flow path plate is formed by a half-piercing method in which pressing is stopped halfway.   The method of manufacturing a liquid discharge head according to claim 6, wherein the groove-like depression formed in the flow path plate is formed by a forging method.   9. The method of manufacturing a liquid discharge head according to claim 6, wherein the pressure generating chamber formed of the groove-shaped depression, the fluid resistance portion, and the nozzle opening are pressed at the same time. A first step of pressing a punch having a shape that becomes the pressure generating chamber and the fluid resistance portion on the thin plate;
A second step of pressing a punch for forming the nozzle hole in the thin plate to form a nozzle opening in which a recess that becomes a nozzle hole is formed;
And performing a third step of opening the nozzle hole by polishing the tip of the nozzle opening formed in the second step, which protrudes from the surface on which the droplets of the thin plate are discharged. A method for manufacturing a liquid discharge head according to claim 6.   11. The method of manufacturing a liquid discharge head according to claim 10, wherein the first step and the second step are a forging method that transfers the punch shape of the pressure generating chamber, the fluid resistance portion, and the nozzle hole. . A first step of pressing a punch having a shape that becomes the pressure generating chamber and the fluid resistance portion on the thin plate;
A second step of polishing the surface protruding to the surface facing the bottom of the groove-shaped depression formed by the pressing;
A third step of pressing a punch for forming the nozzle hole to form a nozzle opening in which a recess to be the nozzle hole is formed;
9. The liquid discharge according to claim 6, wherein the fourth step of polishing the tip of the nozzle opening formed by the third step to open the nozzle hole is performed. Manufacturing method of the head.   13. The method of manufacturing a liquid discharge head according to claim 12, wherein the first step is a harp etching in which pressing of the thin plate is stopped halfway by pressing to form a groove recess.

Images