JP6264873B2 - Droplet discharge head, droplet discharge apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a droplet discharge head, a droplet discharge device including the droplet discharge head, and an image forming apparatus including the droplet discharge head or the droplet discharge device. The present invention relates to a droplet discharge head, a droplet discharge device, and an image forming apparatus used in an image forming apparatus such as an apparatus, a plotter, or a multi-function machine having a plurality of functions.

  As an image forming apparatus such as a copying machine, a facsimile machine, a printer, a plotter, and a complex machine of these, for example, a droplet discharge device composed of a droplet discharge head is used, and a recording material (hereinafter also referred to as a sheet, but the material is limited) In addition, a recording medium, a sheet, a recording medium, a recording paper, a transfer material, a recording paper, and the like are used interchangeably, and an ink as a liquid is attached to the recording material to form an image (recording and printing) In other words, a so-called ink jet type image forming apparatus (hereinafter also referred to as an ink jet recording apparatus) is known.

  2. Description of the Related Art Ink jet recording apparatuses are mainly provided with a droplet discharge device configured to discharge minute droplets of ink only when recording is necessary. In this droplet discharge device, a vibration plate is provided on a part of the wall of a liquid chamber (common liquid chamber) filled with ink, and the vibration plate is displaced by a piezoelectric actuator or the like to increase the pressure in the liquid chamber and to discharge ink from the nozzle. There are known a piezoelectric type to be discharged and a thermal type in which a heating element that generates heat by energization is provided in the liquid chamber, and the pressure in the liquid chamber is increased by bubbles generated by the heat generation of the heating element to discharge ink. In either method, the pressure generation source is driven by a drive signal from a drive circuit for driving the droplet discharge device, and ink droplets are discharged from the discharge port to land on the recording medium.

  If the pressure fluctuation in the common liquid chamber affects the liquid in the individual liquid chamber communicating with the nozzle, unintentional liquid droplet leakage or discharge from the nozzle may occur. If there is an influence due to such pressure propagation, the ejection of droplets becomes unstable and a high quality image cannot be obtained.

Therefore, it is known to provide a member (damper) having elasticity or flexibility for absorbing the influence of pressure propagation on a part of the wall surface of the common liquid chamber.
Since the damper is required to be thin and flexible, it is common to use a material that is easily permeable and breathable, but by using a material that is easily permeable and breathable as a damper member, There is a possibility that the ink will evaporate and the ink is dried, resulting in ejection failure.

In order to avoid this, the space opposite to the surface in contact with the ink via the damper (hereinafter referred to as “damper chamber”, “buffer chamber”, etc.) is a sealed space so as not to directly touch the atmosphere. It is possible.
However, when the damper chamber is a sealed space, the damper is displaced when expansion of the trapped air occurs due to a change in the environmental temperature or the like, and the damper is configured to absorb pressure fluctuations to the common liquid chamber due to discharge. Function may be impaired.

In view of this, a droplet discharge head has been proposed in which an air communication path that connects the damper chamber and the outside (atmosphere) is formed (see, for example, Patent Documents 1 and 2).
Patent Document 1 has a communication path that connects the buffer chamber and the outside of the head, and the wall portion between the common flow path and the buffer chamber has a deformable portion and a thickness larger than the deformable portion. A liquid discharge head is disclosed in which the opening on the buffer chamber side of the communication passage is provided at a position facing the wall portion, and is opposed to a portion that is thicker than the deformable portion. ing.

In the configuration in which the atmosphere communication passage is formed in the head frame itself as in Patent Document 1, or the configuration in which the atmosphere communication passage is provided in the plate on which the diaphragm or the individual liquid chamber is formed, the length of the atmosphere communication passage is regulated. It is difficult to change to a desired length.
On the other hand, Patent Document 2 discloses an ink jet recording head in which the air opening hole is opened to the atmosphere through a long hole longer than the shortest straight line connecting the opening surfaces at both ends. Specifically, an air communication hole having a spiral shape or a part of a mesh shape is described.

In the recording head described in Patent Document 2, the path length is increased by making the shape of the long hole connecting the opening surfaces at both ends of the air opening hole into a spiral shape or a mesh shape. In order to provide such an air communication path having a shape other than a straight line in the head frame, for example, a process of forming a part of the communication path in the cross section of a member obtained by dividing the head frame and joining them is required. .
However, when joining components in which the head frame is divided, there is a problem that it is difficult to completely seal the joining surface and liquid leakage occurs.

  Accordingly, in view of the above problems, the present invention provides a droplet discharge head capable of preventing the occurrence of liquid leakage by forming an air communication path longer than the shortest straight line connecting both opening ends without dividing the head frame. The purpose is to provide.

In order to solve the above problems, a droplet discharge head according to the present invention includes a nozzle that discharges droplets, an individual liquid chamber that communicates with the nozzle, and a common liquid chamber that stores liquid to be supplied to the individual liquid chamber. A pressure generating means for discharging droplets from the nozzle, a deformable damper provided on a part of a wall surface of the common liquid chamber, an air adjacent to the common liquid chamber via the damper, and A damper chamber having an air communication hole communicating therewith, having a unit path having at least one bent portion in a virtual plane defined in the horizontal direction, and a plurality of the unit paths are provided in the vertical direction, and the unit path An atmosphere communication path member in which one communication path is formed by being connected to a unit path on another virtual plane adjacent in the vertical direction at the end of the air communication path, and one of the communication paths of the atmosphere communication path member The open end of Opening the space serial damper chamber, with the other open end is connected to the atmosphere communication hole of the damper chamber, the damper chamber is formed inside the frame that defines the common liquid chamber, wherein The atmosphere communication path member is a droplet discharge head provided in the damper chamber .

  According to the droplet discharge head of the present invention, a droplet discharge that can prevent liquid leakage by forming an air communication path longer than the shortest straight line connecting both opening ends without dividing the head frame. A head can be provided.

1 is an external perspective view showing an embodiment of an image forming apparatus of the present embodiment. It is sectional drawing which shows an example of the basic composition of the droplet discharge apparatus of this embodiment. It is (A) cross-sectional schematic diagram which shows an example of an air | atmosphere communication channel member, (B) exploded perspective view, and (C) upper surface schematic diagram. It is (A) whole schematic diagram which shows an example of an air | atmosphere communication channel member, (B) The side view of a longitudinal direction, (C) The side view of a transversal direction, (D) It is explanatory drawing of the unit path | route on a virtual plane. It is sectional drawing which shows an example of the basic composition of the droplet discharge apparatus of this embodiment. It is sectional drawing which shows an example of the actuator unit and nozzle plate which comprise the droplet discharge head of this embodiment.

  Hereinafter, a droplet discharge head, a droplet discharge device, and an image forming apparatus according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

As will be described in the following embodiments, a droplet discharge head according to the present invention includes a nozzle (nozzle 11) for discharging droplets, an individual liquid chamber (individual liquid chamber 27) communicating with the nozzle, A common liquid chamber (common liquid chamber 31) for storing liquid to be supplied to the individual liquid chamber, pressure generating means (actuator unit 20) for discharging droplets from the nozzle, and a wall surface of the common liquid chamber. A deformable damper (damper 33) provided in a section, a damper chamber (damper chamber 34) having an air communication hole (atmosphere communication hole 42a) adjacent to the common liquid chamber via the damper and communicating with the atmosphere; , And a unit path having at least one bent portion in a virtual plane (virtual plane 87) defined in the horizontal direction, and a plurality of the unit paths are provided in the vertical direction, and are perpendicular to the end of the unit path. direction An atmosphere communication path member (atmosphere communication path member 80) in which one communication path is formed by being connected to a unit path on another adjacent virtual plane is further provided, and one of the communication paths of the atmosphere communication path member Is open to the space of the damper chamber, and the other open end is connected to the air communication hole of the damper chamber.
In addition, a droplet discharge device according to the present invention includes the droplet discharge head and a liquid storage unit (ink tank 60) that stores liquid to be supplied to the common liquid chamber of the droplet discharge head. The image forming apparatus includes the droplet discharge head or the droplet discharge device.
In addition, the code | symbol in embodiment and the example of application are shown in the parenthesis.

(Droplet ejection head, droplet ejection device)
FIG. 2 is a cross-sectional view showing the basic configuration of the droplet discharge device.
In the droplet discharge device 1 shown in FIG. 2, an actuator unit 20 and a nozzle plate 10 that discharge droplets are mounted on a frame 30.

FIG. 6 shows a partial cross-sectional view of the actuator unit 20 and the nozzle plate 10 (a cross-sectional view of the left half from the center of the droplet discharge head body).
A plurality of nozzles 11 are formed on the nozzle plate 10. The individual liquid chamber substrate 22 is disposed on the upper surface of the nozzle plate 10. A plurality of individual liquid chambers 27 are formed on the individual liquid chamber substrate 22. Each individual liquid chamber 27 communicates with each nozzle 11, and its upper wall is formed by a diaphragm 24. A fluid resistance 28 is disposed on one side of each individual liquid chamber 27 and communicates with the liquid supply port 23. A drive circuit member 26 is installed at the center of the diaphragm 24, and piezoelectric elements 25 are installed on both sides thereof. Electrodes (not shown) are formed above and below the piezoelectric element 25, and the electrode pattern (not shown) is connected to the drive circuit member 26 through individual wiring. The holding substrate 21 is disposed on the upper surface of the individual liquid chamber substrate 22. A concave portion 29 is formed in the holding substrate 21 at a position corresponding to the diaphragm 24. The recess 29 is disposed so as to surround the piezoelectric element 25.

(Nozzle plate)
The nozzle plate 10 is a substrate on which ink ejection nozzles 11 are arranged, and any material can be used from the required rigidity and workability. Examples include metals or alloys such as SUS and Ni, inorganic materials such as silicon and ceramics, and resin materials such as polyimide. The processing method of the nozzle can be arbitrarily selected from the characteristics of the material and the required accuracy and workability, and examples thereof include electroforming plating method, etching method, press processing method, laser processing method, photolithography method, etc. . The nozzle aperture diameter, the number of arrays, and the array density can be set to an optimum combination in accordance with the specifications required for the ink head.

(Individual liquid chamber substrate)
In the individual liquid chamber substrate 22, an individual liquid chamber 27, an ink supply path, and an ink supply port 23 are formed. The material of the individual liquid chamber substrate 22 can be arbitrarily selected from the workability and physical properties, but it is preferable to use a silicon substrate that can be processed by photolithography at 300 dpi (about 85 μm pitch) or more. As a processing method of the liquid chamber, any method can be used. When the above-described photolithography method is used, either a wet etching method or a dry etching method can be used. In any method, since the individual liquid chamber 27 side of the diaphragm 24 is made of a silicon dioxide film or the like, an etch stop layer can be formed, so that the height of the liquid chamber can be controlled with high accuracy.

The individual liquid chamber 27 has a function of applying pressure to the ink and discharging droplets from the nozzles. A diaphragm 24 is formed on the individual liquid chamber 27.
Although any material can be selected as the material of the diaphragm 24, it is preferable to use a material having high rigidity such as silicon, nitride, oxide, or carbide. Alternatively, a stacked structure of these materials may be used. In the case of a laminated film, an example is a configuration in which Si ₃ N _{4 serving as} tensile stress and SiO _{2 serving} as compressive stress are alternately laminated to relieve stress.

  The thickness of the diaphragm 24 can be selected according to desired characteristics, but is generally preferably in the range of 0.5 μm to 10 μm, and more preferably in the range of 1.0 μm to 5.0 μm. If the diaphragm 24 is too thin, the diaphragm 24 is likely to be damaged due to cracks or the like, and the natural frequency of the diaphragm 24 is lowered, so that the driving frequency cannot be increased. On the other hand, when the diaphragm 24 is too thick, the displacement becomes small and the output efficiency decreases.

On the diaphragm 24, a piezoelectric element 25 in which a lower electrode, a piezoelectric body, and an upper electrode are stacked is formed.
Although the lower electrode and the upper electrode are not shown, any conductive material can be used. Examples include metals, alloys, and conductive compounds. A single layer film or a laminated film of these materials may be used. Further, since it is necessary to select a material that does not react with the piezoelectric body and does not diffuse, it is necessary to select a highly stable material. Further, if necessary, the adhesive layer may be formed in consideration of the piezoelectric body, the diaphragm 24, and the adhesiveness. Examples of the electrode material include Pt, Ir, Ir oxide, Pd, Pd oxide and the like as highly stable materials. Further, examples of the adhesion layer with the diaphragm 24 include Ti, Ta, W, Cr, and the like.

As a piezoelectric material constituting the piezoelectric element 25, a ferroelectric material exhibiting piezoelectricity can be used. As examples, lead zirconate titanate and barium titanate are generally used. Arbitrary methods can be used as the method for forming the piezoelectric body, and examples thereof include a sputtering method and a sol-gel method. Among these methods, the sol-gel method is preferable because the film forming temperature is low.
The upper electrode and the piezoelectric body need to be patterned for each individual liquid chamber 27. For patterning, a normal photolithography method can be used. Also, when the piezoelectric film is formed by the sol-gel method, a spin coating method or a printing method can also be used.

  The piezoelectric element 25 needs to be formed above the individual liquid chamber 27. When formed on the partition wall that divides the individual liquid chamber 27, the deformation of the vibration plate 24 is hindered, which causes a decrease in discharge efficiency and damage of the piezoelectric element 25 due to stress concentration.

  A fluid resistance 28 communicating with the individual liquid chamber 27 is formed on the individual liquid chamber substrate 22. The fluid resistance 28 has a function of supplying ink from the common liquid chamber 31 to the individual liquid chamber 27, and at the same time, prevents the back flow of ink by the pressure generated in the individual liquid chamber 27 by driving the piezoelectric element 25. It has a function of discharging from the liquid. Therefore, it is necessary to reduce the cross-sectional area of the individual liquid chamber 27 in the ink flow direction and increase the fluid resistance. When silicon is used for the individual liquid chamber substrate 22 and the individual liquid chamber 27 and the fluid resistance 28 are formed using a photolithography method and an etching method, there is an advantage that the individual liquid chamber 27 can be processed under the same conditions as the individual liquid chamber 27. The fluid resistance 28 communicates with the common liquid chamber 31 through the ink supply port 23 in which the vibration plate 24 is opened.

  The individual liquid chamber 27 is partitioned by a partition, and the piezoelectric element 25 corresponding to each is formed. The height of the individual liquid chamber 27 can be arbitrarily set from the head characteristics, but is preferably in the range of 20 to 100 μm. The partition walls of the individual liquid chambers 27 can be arbitrarily set in accordance with the arrangement density, but the partition wall width is preferably 10 to 30 μm at 300 dpi. Further, when the partition wall width is narrow, when the piezoelectric element 25 of the adjacent individual liquid chamber 27 is driven, mutual interference occurs between the adjacent liquid chambers, and the discharge variation increases. When narrowing the partition wall width, it is possible to reduce the height of the liquid chamber.

(wiring)
Although not shown, in order to input a drive signal to the arranged piezoelectric elements 25, an individual wiring is drawn from the upper electrode and a wiring is drawn from the lower electrode. From the upper electrode, it is drawn out from the arranged upper electrode to the individual wiring pad through the individual wiring that is a part of the wiring layer, connected to the driving IC, and further drawn out from the driving IC to the connecting pad through the wiring. The lower electrode is drawn out to the connection pad through the wiring. It is desirable to form the wiring with the same material and the same process. As the wiring material, a metal, an alloy, or a conductive material having a low resistance value can be used. Further, it is necessary to use a material having a low contact resistance with the upper electrode and the lower electrode. Examples include Al, Au, Ag, Pd, Ir, W, Ti, Ta, Cu, Cr, and the like, and a laminated structure of these materials may be used to reduce contact resistance. As a material for reducing the contact resistance, any conductive compound may be used. Examples include oxides and nitrides such as Ta ₂ O ₅ , TiO ₂ , TiN, ZnO, In ₂ O ₃ , SnO, and composite compounds thereof. The film thickness can be arbitrarily set, but is preferably 3 μm or less. In addition, it is preferable to employ a film forming method with high film thickness uniformity such as a vacuum film forming method. Since these wirings also serve as a joint surface with the holding substrate 21 described later, it is necessary to adopt a film thickness / film forming method that can ensure height uniformity.

(Holding substrate)
Since the individual liquid chamber substrate 22 is as thin as 20 to 100 μm, the holding substrate 21 is bonded to the side facing the nozzle plate 10 in order to ensure the rigidity of the individual liquid chamber substrate 22.
Although any material can be used as the material of the holding substrate 21, it is necessary to select a material having a thermal expansion coefficient close to prevent the individual liquid chamber substrate 22 from warping. Therefore, it is preferable to use ceramic materials such as glass, silicon, SiO ₂ , ZrO ₂ , and Al ₂ O ₃ .

  The holding substrate 21 has an opening communicating with the arrangement direction of the individual liquid chambers 27 and becomes a part of the common liquid chamber 31. Further, in order to secure a space in which the piezoelectric element 25 can be driven and the diaphragm 24 can be displaced, a recess 29 is formed in a region facing the individual liquid chamber 27. The recess 29 is preferably divided for each individual liquid chamber 27 and bonded on the individual liquid chamber 27 partition. Thereby, the rigidity of the individual liquid chamber substrate 22 having a thin plate thickness can be increased, and the mutual interference between adjacent liquid chambers when the piezoelectric element 25 is driven can be reduced. For this purpose, the holding substrate 21 is preferably not a low-rigidity material such as resin but a high-rigidity material such as silicon. Further, since the concave portion 29 of the holding substrate 21 is partitioned for each individual liquid chamber 27, high processing accuracy is required for high density, and the holding substrate 21 partition wall width is 5 to 20 μm in the 300 dpi head. It is desirable to do.

  As shown in the overall configuration diagram of FIG. 2, a common liquid chamber 31 for supplying liquid to the individual liquid chamber 27 of the actuator unit 20 is formed in the frame 30, and the common liquid chamber 31 is provided in the frame 30. The ink pipe 60 communicates with the ink tank 60 through ink paths 41, 71, 51 provided in the connecting pipe 32, the flow path member 40, the elastic member 70, and the connection path member 50, respectively.

The frame 30 has a role of holding the entire droplet discharge head and is formed integrally with the common liquid chamber 31.
Examples of the material of the frame 30 include iron such as S45C, alloys such as SUS, inorganic materials such as silicon and ceramics, resin materials such as epoxy and PPS, and the like depending on required rigidity and workability. Although it can select suitably, a thing with corrosion resistance and low dust generation property among these is preferable. In the case of a resin material such as epoxy or PPS, there is a possibility that a dimensional error due to thermal shrinkage may be a problem at the time of joining with other components. Therefore, it is preferable to use 30 to 50% glass fiber.
The processing method of the frame 30 can be selected according to the material, and examples thereof include etching, press processing, laser processing, photolithography, and injection molding.

  The ink tank 60 is a tank unit that stores ink to be supplied to the common liquid chamber 31. A connecting path member 50 is fitted in the ink tank 60, and an elastic member 70 such as a sheet packing is provided between the connecting path member 50 and the flow path member 40 to prevent liquid leakage. Has been.

  Further, the ink path 51 of the connection path member 50 formed from the ink tank 60 and the ink path 71 of the elastic member 70 communicate with the connection pipe 32 provided in the frame 30, so that the ink path 41 of the flow path member 40. The route is converted at.

  Further, a damper 33 for absorbing pressure fluctuation is provided on a part of the wall surface of the frame 30 on the common liquid chamber 31 side. The damper 33 is a member having elasticity or flexibility for absorbing the pressure propagation generated in the common liquid chamber 31 due to the ejection of ink from the nozzle 11.

The damper 33 is preferably thin and low in rigidity, and is preferably integrally formed with the common liquid chamber 31.
Examples of the material of the damper 33 include alloys such as SUS, metal materials such as Ni, inorganic materials such as silicon and ceramics, resin materials such as epoxy and PPS, rubber (raw rubber), thermoplastic elastomer, and thermosetting elastomer. Examples thereof include elastic bodies such as (elastic rubber). Among these, a diaphragm made of a thermosetting elastomer is preferable. Since the thermosetting elastomer has a low elastic modulus, it can have a thickness and can efficiently attenuate pressure fluctuations. In addition, since it can be integrally formed with the frame 30, the number of parts manufacturing steps can be reduced, and the cost can be reduced.

  Since the damper 33 is a member having elasticity and flexibility, there is a concern that moisture may permeate. When the water evaporation in the common liquid chamber 31 proceeds, the viscosity of the ink increases, leading to ejection failure such as non-ejection.

  In order to suppress this, on the opposite side of the damper 33 from the common liquid chamber 31, the flow path member 40 is covered with an upper portion of the frame 30 and sealed on the outer periphery thereof. When completely sealed, the damper chamber 34 formed between the frame 30 and the flow path member 40 becomes a sealed space, so that there is no air escape space and the displacement of the damper 33 is hindered. Further, when there is a fluctuation in atmospheric pressure due to environmental changes or the like, the internal pressure of the damper chamber 34 increases, so it is necessary to keep the damper chamber 34 in communication with the atmosphere.

In the droplet discharge device 1 shown in FIG. 2, an atmosphere communication path 42 that is a hole formed in the flow path member 40 and an atmosphere communication path member 80 are provided as means for communicating the damper chamber 34 with the atmosphere. .
The atmosphere communication path 42 has a pattern shape which is an atmosphere communication hole 42 a penetrating the damper chamber 34 on the lower surface of the flow path member 40 and a snake-like concave portion reciprocating from the air communication hole 42 a on the upper surface of the flow path member 40. A groove 42b is formed, and a cover seal 90 is attached to cover the formation position of the through hole 42a and the pattern-like groove 42b. The cover seal 90 is stuck with an adhesive so that the pattern-like grooves 42b are separated from each other.

  The material of the flow path member 40 is preferably one having corrosion resistance and low dust generation properties, such as alloys such as SUS, metal materials such as Ni, inorganic materials such as silicon and ceramics, epoxy, PPS, heat Examples thereof include resin materials such as plastic elastomers and thermosetting elastomers. Of these, resin materials that can be injection-molded (for example, polyacetal) are more preferable.

  On the other hand, the atmosphere communication path member 80 has at least one bent portion in a virtual plane defined in the horizontal direction, and has continuous unit paths having different path traveling directions through the bent section. A plurality of paths are provided in the vertical direction, and one communication path is formed by connecting to the unit path on another virtual plane adjacent in the vertical direction at the end of the unit path. One open end of the communication path of the atmospheric communication path member 80 is open to the space of the damper chamber 34, and the other open end is connected to the atmospheric communication hole 42a.

The atmosphere communication passage member 80 is provided inside the frame 30 that defines the common liquid chamber 31, specifically, inside a damper chamber 34 that is formed inside the frame 30 as shown in FIG. 2. preferable.
By providing the atmosphere communication path member 80 inside the frame 30, an effect of suppressing the amount of moisture evaporation from the damper 33 can be obtained. The reason why this effect is obtained will be described by taking the case where the damper 33 is made of a polymer film as an example.
Generally, the gas permeation amount of a polymer film is represented by the following formula.
Q = D * S * (p1-p2) * A * t / L
(However, Q is a gas permeation amount, D is a diffusion coefficient, S is a solubility coefficient, (p1-p2) is a pressure difference on both sides of the film, A is a cross-sectional area, t is time, and L is thickness.)
As shown by the above formula, the gas permeation amount is proportional to the pressure difference between both sides of the film.

By providing the atmosphere communication passage member 80 inside the frame 30, the volume of the damper chamber 34 is reduced, and the partial pressure of water vapor in the damper chamber 34 is likely to increase due to moisture evaporated from the film. Therefore, it is considered that the pressure difference between the two sides via the damper 33 becomes small, and the amount of moisture evaporation can be suppressed.
Further, by being installed inside the frame 30, it is possible to prevent clogging due to foreign matter or the like.
As described above, by providing the atmosphere communication path member 80 inside the frame 30, the function of the damper 33 can be reliably exhibited, the viscosity of the discharged liquid can be prevented from being increased, and the discharge performance can be improved. . That is, it is preferable that the damper chamber 34 is formed inside the frame 30, and the atmosphere communication path member 80 is provided inside the damper chamber 34.

(First embodiment)
The droplet discharge device according to the present embodiment includes an atmospheric communication path member 80 configured by a plurality of stacked substrates.
3A and 3B are views showing the atmospheric communication channel member 80 of the present embodiment, FIG. 3A is a schematic cross-sectional view, FIG. 3B is an exploded perspective view, and FIG. 3C is a schematic top view. . Note that FIG. 3A is a cross-sectional view taken along line AA in FIGS. 3B and 3C. Moreover, the arrow in FIG. 3 (B) has shown the direction through which the gas flows from the damper chamber 34 inside to the exterior (atmosphere).

The atmosphere communication path member 80 has a bent portion in a virtual plane defined in the horizontal direction, and a communication path substrate in which a continuous unit path 83 having a course different by 180 degrees is formed in a groove shape through the bent portion. A plurality of 81 are stacked. One end of the unit path 83 is connected to the unit path 83 on another communication path substrate 81 adjacent in the vertical direction to form one communication path. Specifically, the communication path substrate through hole 82 is formed at one end of the unit path 83, and the unit paths 83 on the adjacent communication path substrate 81 are connected via the communication path substrate through hole 82.
The communication path substrate through hole 82 at one end of the unit path of the stacked lowermost communication path substrate 81 (81b in FIG. 3) opens into the space of the damper chamber 34, and the stacked uppermost communication path substrate 81 (FIG. 3, the communication passage board through hole 82 at one end of the unit path 83 of 81 a) is connected to the air communication hole 42 a of the damper chamber 34.

As shown in FIG. 3B, the communication path substrate 81 provided with the groove-shaped unit path 83 and the communication path substrate through hole 82 is arranged symmetrically between the substrates where the positions of the communication path substrate through holes 82 are adjacent. As a result, the three-dimensional communication path is formed by alternately overlapping.
In this way, by adopting a configuration in which a plurality of communication path substrates 81 are stacked, the length of the communication path to be formed can be increased without changing the mold as the atmospheric communication path member 80. Since it can be adjusted by the number, cost reduction can be realized.
Although FIG. 3A shows a mode in which two communication path substrates 81 are stacked, the number of stacked layers is not limited.

  The material of the communication path substrate 81 constituting the atmosphere communication path member 80 is preferably a material having corrosion resistance and low dust generation properties, such as alloys such as SUS, metal materials such as Ni, silicon, ceramics, and the like. Examples thereof include resin materials such as inorganic materials, epoxy, PPS, thermoplastic elastomer, and thermosetting elastomer. Of these, resin materials that can be injection-molded (for example, polyacetal) are more preferable.

The flow path member 40 and the atmospheric communication path member 80 are each made of resin, and the atmospheric communication path member 80 and the flow path member 40 are joined together by an adhesive, and the communication path of the atmospheric communication path member 80 and the atmospheric air of the flow path member 40 are combined. It is preferable that the communication hole 42a is connected.
In the method of creating a part in which the frame 30 is divided to form the atmosphere communication path and joining them, the number of processes increases, and high joining accuracy is required, leading to an increase in cost. On the other hand, in the configuration of the present embodiment, the atmosphere communication passage having a desired length can be easily formed without dividing the frame 30, and mass production can be performed at low cost.

(Second Embodiment)
The droplet discharge device of the present embodiment includes an atmospheric communication path member 80 configured by an integrated atmospheric communication path unit in which a plurality of unit paths are formed.
4A and 4B are views showing the atmospheric communication path member 80 of the present embodiment. FIG. 4A is an overall schematic view of an atmospheric communication path unit 89 described later of the atmospheric communication path member 80, and FIG. FIG. 4C is a side view of the communication path member 80 in the longitudinal direction, FIG. 4C is a side view of the atmospheric communication path unit 89 in the short direction, and FIG. 4D is an explanatory view of the unit path on the virtual plane. The arrows in FIGS. 4B and 4D indicate the direction of gas flow from the inside of the damper chamber 34 to the outside (atmosphere).

  The atmosphere communication path member 80 includes a plurality of tubular paths 85 penetrating in the longitudinal direction of the horizontal plane, and an air communication path formed with a groove-like coupling path 86 that connects the two adjacent tubular paths on the opening surface 84 of the tubular path 85. It comprises a passage unit 89 and a seal member 88 that covers the opening surface 84 of the tubular passage 85 of the atmospheric communication passage unit 89.

  In the horizontal direction, two tubular paths 85 form a U-shaped unit path via a groove-shaped connecting path 86 formed in the horizontal direction, and a plurality of unit paths are provided in the vertical direction, and the end of the unit path By connecting through the groove-like connecting path 86 formed in the vertical direction with the opening surface of another unit path adjacent in the vertical direction, and by being covered with the seal member 88, one communication path is formed. It is formed.

As shown in FIG. 4D, in the virtual plane 87 defined in the horizontal direction, a unit path having a bent portion (a unit path in which paths having different traveling directions through the bent portion are continuous) is formed. A plurality of paths are provided in the vertical direction, and one communication path is formed by being connected to a unit path on another virtual plane adjacent in the vertical direction at the end of the unit path.
In the formed communication path, among the groove-like connection paths 86 formed in the vertical direction, the lowermost end 86a is open to the space of the damper chamber 34, and the uppermost end 86b is the atmospheric communication hole 42a of the damper chamber 34. Connected.

  Since the atmosphere communication path member 80 of this embodiment is composed of an integral unit, the joining process for stacking a plurality of members can be shortened.

Further, the atmosphere communication path unit 89 may be directly attached to the frame 30. For example, an air communication hole may be provided in the frame 30, and the air communication hole may be connected to the opening end of the air communication path unit 89 to form one communication path.
The atmosphere communication path member 80 includes a plurality of tubular paths 85 penetrating in the longitudinal direction of the horizontal plane, and an air communication path formed with a groove-like coupling path 86 that connects the two adjacent tubular paths on the opening surface 84 of the tubular path 85. It has a passage unit 89, and the opening surface 84 of the tubular passage 85 of the atmosphere communication passage unit 89 is covered with the inner wall of the frame 30, and the two tubular passages 85 are connected via the groove-like connection passage 86 to form a unit passage. It is also possible to use this mode. According to this aspect, the seal member 88 can be omitted.

(Third embodiment)
The droplet discharge device according to the present embodiment includes a member in which the atmosphere communication path member 80 and the flow path member 40 are integrally formed.
FIG. 5 shows a cross-sectional view of the droplet discharge device 1 of the present embodiment. The droplet discharge device 1 shown in FIG. 5 has the same configuration as the droplet discharge device 1 shown in FIG. 2 except that the atmosphere communication path member 80 and the flow path member 40 are integrally formed.

  The atmospheric communication path member 80 in the present embodiment has, for example, the shape shown in FIG. 4, and the plurality of tubular paths 85 constituting the communication path are made the same as the drawing direction of the flow path member 40 so as to be integrated. Can be molded.

In the first to third embodiments described above, the unit path of the atmospheric communication path member is an example of a unit path whose course is different by 180 degrees through the bent portion. The angle at which the path bends and the traveling direction of the path (also expressed as a path) are not limited, and the number of bent portions provided in the unit path is not limited.
Any atmospheric communication path member that has at least one bent portion and has a unit path whose path is bent via the bent portion acts as a resistance path that reduces air permeability and moisture permeability.

(Image forming device)
Hereinafter, an embodiment of an image forming apparatus including a droplet discharge head or a droplet discharge device 1 according to the present invention will be described with reference to a perspective view shown in FIG. 1 (A) and a configuration of a mechanism unit shown in FIG. 1 (B). This will be described with reference to the side view.

  The image forming apparatus 100 includes a carriage 101 that can move in the main scanning direction inside the apparatus main body, a droplet discharge device 1 mounted on the carriage 101, an ink cartridge 102 that supplies ink to the droplet discharge device 1, and the like. A paper feed cassette (or a paper feed tray) 104 on which a large number of recording papers P can be stacked from the front side is detachably attached to the lower part of the apparatus main body. Yes. Further, it has a manual feed tray 105 that is opened to manually feed the recording paper P, takes in the recording paper P fed from the paper feed cassette 104 or the manual feed tray 105, and prints a required image by the printing mechanism unit 103. After recording, the paper is discharged to a paper discharge tray 106 mounted on the rear side.

  The print mechanism 103 holds a carriage 101 slidably in the main scanning direction by a main guide rod 107 and a sub guide rod 108 which are guide members horizontally mounted on left and right side plates (not shown). A droplet discharge device 1 that discharges ink droplets of each color (Y), cyan (C), magenta (M), and black (B) is arranged in a direction intersecting a main scanning direction with a plurality of ink discharge ports (nozzles). However, it is mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 102 for supplying ink of each color to the droplet discharge device 1 is replaceably mounted on the carriage 101.

  The ink cartridge 102 is provided with an air opening communicating with the atmosphere at the upper side, and a supply port for supplying ink to the droplet discharge device 1 at the lower side, and has a porous body filled with ink inside. The ink supplied to the droplet discharge device 1 is maintained at a slight negative pressure by the capillary force of the material. In addition, although a plurality of droplet discharge devices 1 for each color are used as the droplet discharge device 1, a single droplet discharge device 1 having a nozzle for discharging ink droplets of each color may be used.

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

  On the other hand, in order to convey the recording paper P set in the paper feeding cassette 104 to the lower side of the droplet discharge device 1, a paper feeding roller 113 and a friction pad 114 for separating and feeding the recording paper P from the paper feeding cassette 104, The guide member 115 that guides the recording paper P, the transport roller 116 that reverses and transports the fed recording paper P, the transport roller 117 that is pressed against the peripheral surface of the transport roller 116, and the recording paper from the transport roller 116 And a leading end roller 118 for defining a feed angle of P. The transport roller 116 is rotationally driven through a gear train by a sub-scanning motor.

  In addition, a printing receiving member 119 is provided as a paper guide member for guiding the recording paper P fed from the transport roller 116 corresponding to the moving range of the carriage 101 in the main scanning direction on the lower side of the droplet discharge device 1. ing. A conveyance roller 120 and a spur 121 that are rotationally driven to send the recording paper P in the paper discharge direction are provided on the downstream side of the printing receiving member 119 in the paper conveyance direction, and the recording paper P is further sent to the paper discharge tray 106. A paper discharge roller 123, a spur 124, and guide members 125 and 126 that form a paper discharge path are disposed.

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

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

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

  In the “recording” in this specification, not only an image having a meaning such as a character or a figure is imparted to a recording medium, but also an image having no meaning such as a pattern is imparted to the recording medium ( Simply landing a droplet on a medium). The “image forming apparatus” of the liquid discharge recording system means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, and the like. .

  “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. In addition, the “image” is not limited to a planar one, but includes an image given to a three-dimensionally formed image, and an image formed by three-dimensionally modeling a solid itself.

DESCRIPTION OF SYMBOLS 1 Droplet discharge device 10 Nozzle plate 11 Nozzle 20 Actuator unit (pressure generation means)
21 Holding substrate 22 Individual liquid chamber substrate 23 Liquid supply port 24 Vibration plate 25 Piezoelectric element 26 Drive circuit member 27 Individual liquid chamber 28 Fluid resistance 29 Recess 30 Frame 31 Common liquid chamber 32 Connecting pipe 33 Damper 34 Damper chamber 40 Channel member 41 Ink path 42 Atmospheric communication path 42a Atmospheric communication hole 42b Patterned groove 50 Connection path member 51 Ink path 60 Ink tank 70 Elastic member (liquid sealing member)
71 Ink path 80 Atmospheric communication path member 81 Communication path board 82 Communication path board through hole 84 Tubular path opening 85 Tubular path 86 Groove-shaped coupling path 87 Virtual plane 88 Seal member 89 Atmospheric communication path unit 100 Image forming apparatus 101 Carriage 102 Ink Cartridge 103 Printing mechanism 104 Paper feed cassette 105 Manual feed tray 106 Paper discharge tray 107 Main guide rod 108 Subordinate guide rod 109 Main scanning motor 110 Drive pulley 111 Driven pulley 112 Timing belt 113 Paper supply roller 114 Friction pad 115 Guide member 116 Conveyance roller 117 Conveying roller 118 Leading roller 119 Printing receiving member 120 Conveying roller 121 Spur 123 Paper ejection roller 124 Spur 125, 126 Guide member 127 Recovery device P Recording paper

JP 2002-127407 A Japanese Patent No. 5004497

Claims (9)

A nozzle for discharging droplets;
An individual liquid chamber communicating with the nozzle;
A common liquid chamber for storing liquid to be supplied to the individual liquid chamber;
Pressure generating means for discharging droplets from the nozzle;
A deformable damper provided on a part of the wall surface of the common liquid chamber;
A damper chamber adjacent to the common liquid chamber via the damper and having an atmosphere communication hole communicating with the atmosphere; and
On another virtual plane having a unit path having at least one bent portion in a virtual plane defined in the horizontal direction, a plurality of the unit paths being provided in the vertical direction, and adjacent in the vertical direction at the end of the unit path An air communication path member in which one communication path is formed by being connected to the unit path of
One open end of the communication path of the atmospheric communication path member opens to the space of the damper chamber, and the other open end is connected to the atmospheric communication hole of the damper chamber ,
The damper chamber is formed inside a frame that defines the common liquid chamber,
The droplet discharge head according to claim 1, wherein the atmosphere communication path member is provided inside the damper chamber . The atmospheric communication path member is formed by stacking a plurality of communication path substrates in which the unit path is formed in a groove shape, and is connected to the unit path on the other communication path substrate at the end of the unit path. As a result, one communication path is formed,
One end of the unit path of the stacked lowermost communication path substrate is opened to the space of the damper chamber, and one end of the unit path of the stacked uppermost communication path substrate is the atmosphere communication of the damper chamber. The droplet discharge head according to claim 1, wherein the droplet discharge head is connected to a hole. The atmosphere communication path member includes an air communication path unit in which a plurality of tubular paths that penetrate in the longitudinal direction of a horizontal plane and a groove-shaped connection path that connects two tubular paths adjacent to each other on an opening surface of the tubular path are formed. And a sealing member that covers the opening surface of the tubular passage of the atmosphere communication path unit,
Two tubular paths are connected via the groove-shaped connecting path to form the unit path, and a plurality of the unit paths are provided in the vertical direction, and another unit adjacent in the vertical direction at the end of the unit path. One communication path is formed by being connected through a groove-like connection path formed in a direction perpendicular to the opening surface of the path,
Of the groove-like connecting paths formed in the vertical direction, one end at the bottom is open to the space of the damper chamber, and one end at the top is connected to the air communication hole of the damper chamber. The droplet discharge head according to claim 1 . The atmospheric communication path member includes an atmospheric communication path unit in which a plurality of tubular paths penetrating in the longitudinal direction of a horizontal plane and a groove-shaped coupling path connecting two adjacent tubular paths on the opening surface of the tubular path are formed. An opening surface of the tubular passage of the atmospheric communication channel unit is covered with an inner wall of the frame;
Two tubular paths are connected via the groove-shaped connecting path to form the unit path, and a plurality of the unit paths are provided in the vertical direction, and another unit adjacent in the vertical direction at the end of the unit path. One communication path is formed by being connected through a groove-like connection path formed in a direction perpendicular to the opening surface of the path,
Of the groove-like connecting paths formed in the vertical direction, one end at the bottom is open to the space of the damper chamber, and one end at the top is connected to the air communication hole of the damper chamber. The droplet discharge head according to claim 1 . A nozzle for discharging droplets;
An individual liquid chamber communicating with the nozzle;
A common liquid chamber for storing liquid to be supplied to the individual liquid chamber;
Pressure generating means for discharging droplets from the nozzle;
A deformable damper provided on a part of the wall surface of the common liquid chamber;
A damper chamber adjacent to the common liquid chamber via the damper and having an atmosphere communication hole communicating with the atmosphere; and
On another virtual plane having a unit path having at least one bent portion in a virtual plane defined in the horizontal direction, a plurality of the unit paths being provided in the vertical direction, and adjacent in the vertical direction at the end of the unit path An air communication path member in which one communication path is formed by being connected to the unit path of
One open end of the communication path of the atmospheric communication path member opens to the space of the damper chamber, and the other open end is connected to the atmospheric communication hole of the damper chamber,
The atmosphere communication path member includes an air communication path unit in which a plurality of tubular paths that penetrate in the longitudinal direction of a horizontal plane and a groove-shaped connection path that connects two tubular paths adjacent to each other on an opening surface of the tubular path are formed. And a sealing member that covers the opening surface of the tubular passage of the atmosphere communication path unit,
Two tubular paths are connected via the groove-shaped connecting path to form the unit path, and a plurality of the unit paths are provided in the vertical direction, and another unit adjacent in the vertical direction at the end of the unit path. One communication path is formed by being connected through a groove-like connection path formed in a direction perpendicular to the opening surface of the path,
Of the groove-like connecting paths formed in the vertical direction, one end at the bottom is open to the space of the damper chamber, and one end at the top is connected to the air communication hole of the damper chamber. Droplet discharge head. The atmosphere communication hole of the damper chamber is a hole formed in a flow path member that constitutes a wall surface of the damper chamber;
The atmosphere communication path member and the flow path member are made of resin,
2. The atmosphere communication path member and the flow path member are joined by an adhesive, and the communication path of the atmosphere communication path member and the atmosphere communication hole of the flow path member are connected. To 5. The droplet discharge head according to any one of items 1 to 5.   7. The liquid droplet ejection head according to claim 1, wherein the damper is a diaphragm made of a thermosetting elastomer.   8. A droplet discharge comprising: the droplet discharge head according to claim 1; and a liquid storage unit for storing a liquid to be supplied to the common liquid chamber of the droplet discharge head. apparatus.   An image forming apparatus comprising the droplet discharge head according to claim 1 or the droplet discharge device according to claim 8.