JP6248811B2 - Ink jet head and damper member manufacturing method - Google Patents

Description

  The present invention relates to an inkjet head and a method for manufacturing a damper member, and more particularly, to an inkjet head that can reduce the influence between rows of pressure chambers due to crosstalk and a method for manufacturing a damper member used therefor.

  Ink jet heads may have non-uniform ejection performance due to pressure waves generated by driving. This is because a pressure wave generated in the pressure chamber by driving propagates to another pressure chamber communicated by the common ink chamber, and so-called crosstalk is generated that causes a change in the ejection characteristics of the pressure chamber to which the pressure wave has propagated. .

  Conventionally, as a technique for reducing the influence between pressure chambers due to crosstalk, a wall member that intersects a straight extension line connecting an ink inlet and an ink outlet of a pressure chamber is made of a material having a bulk modulus of 40 GPa or less. Technology for forming (Patent Document 1), technology for forming a damper wall that elastically deforms facing the common ink chamber (Patent Document 2), and a damper member having a damper chamber filled with air in the common ink chamber as a separate member An arrangement technique (Patent Document 3) and the like have been proposed.

JP 2007-168185 A JP 2012-106513 A JP 2007-111831 A

  In recent years, an ink jet head has been required to have a performance capable of performing high-definition image recording at a higher speed. For this reason, there has been proposed an ink jet head capable of performing high-density image recording by arranging a plurality of rows of pressure chambers in which a plurality of pressure chambers are arranged side by side.

  However, as the inventors have confirmed, when an inkjet head having a plurality of rows of pressure chambers is driven, the influence of crosstalk becomes larger than that of an inkjet head having a row of pressure chambers, and fluctuations in ejection characteristics occur. It turns out that the problem is noticeable.

  That is, an ink jet head having a structure in which the pressure chambers are constituted by a plurality of rows and the ink inlets of the pressure chambers between the rows communicate with each other by the common ink chamber is generated in the pressure chambers by driving one pressure chamber row. The pressure wave propagates to the pressure chambers in the other rows via the common ink chamber, and affects the ejection characteristics of the pressure chambers in the other rows.

  Therefore, in order to suppress acoustic crosstalk, the techniques described in Patent Documents 1 and 2 are known to use a member having a function of attenuating a pressure wave on the wall surface of the common ink chamber. However, for example, when it is necessary to bring the wall surface of the common ink chamber close to the ink inlet that opens into the common ink chamber in order to suppress acoustic crosstalk, the common ink chamber is narrowed so that a necessary amount of ink is supplied. There is a problem that it is impossible to secure a volume sufficient for storage.

  On the other hand, the technique described in Patent Document 3 has a configuration in which the damper member is arranged as a separate member in the common ink chamber, and therefore, there is an advantage that the damper member can be freely arranged and the volume of the common ink chamber can be secured. However, the damper member filled with air in the damper chamber often uses a flexible film on the damper surface, so that heat generated by driving the inkjet head, such as gel UV ink, ceramic ink, etc. Thus, when ink that needs to be heated to high temperature by a heater or the like is used, the air in the damper chamber expands due to the heat of the high-temperature ink and causes the damper surface to protrude toward the pressure chamber. The protrusion of the damper surface described above may narrow the ink flow path to the pressure chamber, thereby hindering smooth ink supply.

  Patent Document 3 describes that the pressure inside the damper member is equal to or higher than atmospheric pressure. In addition, it is described that the higher the temperature of the air in the usage environment, the larger the volume of the damper chamber due to the expansion of the air, and the pressure inside the damper member rises to be larger than the atmospheric pressure, thereby improving the damping characteristics. ing. Therefore, Patent Document 3 does not consider at all that the ink flow path is narrowed due to the expansion of the damper member.

  In order to prevent the ink flow path from being narrowed due to the expansion of the air in the damper chamber, it is possible to increase the thickness of the film constituting the damper surface to suppress the amount of protrusion during expansion, but if the thickness is increased There is a problem that the efficiency of pressure wave attenuation is reduced and the damper effect is impaired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet head equipped with a damper member that exhibits a damper effect and does not cause the damper surface to protrude toward the pressure chamber and narrow the ink flow path.

  The present invention also provides a method of manufacturing a damper member that can easily manufacture a damper member that exhibits a damper effect and does not cause the damper surface to protrude in the direction of the pressure chamber and narrow the ink flow path. This is the issue.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

1.
Pressure chambers arranged in two or more rows;
A common ink chamber communicating with the pressure chamber via an ink inlet of the pressure chamber;
A damper member in the common ink chamber,
The damper member includes a damper frame and a flexible film, and at least a surface of the damper frame facing the ink inlet is formed by the flexible film, and is defined by the damper frame and the flexible film. An inkjet head characterized in that the internal pressure is a negative pressure.

2.
The separation distance between the ink inlet and the flexible film is arranged at a position that is smaller than the distance between the ink inlet and the ink inlet in a row of the pressure chambers adjacent in the transport direction. 2. The ink-jet head as described in 1 above.

3.
The ink arranged such that a separation distance between the ink inlet and the flexible film is smaller than a distance between the ink inlet and the ink inlet of the adjacent row of pressure chambers in the transport direction. 3. The inkjet head according to item 2, wherein the ratio of the number of inlets is 90% or more of the number of all the ink inlets.

4).
4. The inkjet head according to 1, 2, or 3, wherein the flexible film has a thickness of 10 μm to 150 μm.

5).
5. The inkjet head according to any one of 1 to 4, wherein an internal pressure defined by the damper frame and the flexible film is reduced so as to be 50 kPa or more and less than atmospheric pressure at room temperature. .

6).
Any one of 1 to 5 above, wherein when the damper member is projected from a direction perpendicular to a surface on which the ink inlet exists, the damper member includes the ink inlets of all the pressure chambers. The inkjet head described in 1.

7).
The flexible film of the damper member forms a flat surface or a recessed surface when at a use temperature for discharging ink in the common ink chamber. The inkjet head as described.

8).
8. The ink jet head according to any one of 1 to 7, wherein the flexible film of the damper member forms a flat surface or a recessed surface at room temperature.

9.
9. The inkjet head according to any one of 1 to 8, wherein at least a part of the damper frame is made of metal.

1 0 .
Pressure chambers arranged in two or more rows;
A common ink chamber communicating with the pressure chamber via an ink inlet to the pressure chamber;
A damper member in the common ink chamber,
The damper member is a method of manufacturing the damper member in an ink jet head having a damper frame and a flexible film, and at least a surface of the damper frame facing the ink inlet is formed by the flexible film,
A method for producing a damper member, comprising: a negative pressure forming step in which an internal pressure defined by the damper frame and the flexible film is negative.

1 1 .
In the negative pressure forming step, the internal pressure defined by the damper frame and the flexible film is reduced by bonding the flexible film to the damper frame in a vacuum chamber that has been reduced to a predetermined pressure. method for producing the 1 0, wherein the damper member, characterized in that a negative pressure.

1 2 .
In the negative pressure forming step, after the flexible film is bonded to the damper frame via an adhesive layer, a hollow tube member is inserted into the adhesive layer, and the damper frame and the flexible film define the flexible film. method for producing internal by pulling through the pipe member to gas, the 1 0, wherein the damper member, characterized in that the pressure of the internal negative pressure is.

  According to the present invention, it is possible to provide an ink jet head equipped with a damper member that exhibits a damper effect and does not cause the damper surface to protrude toward the pressure chamber and narrow the ink flow path.

  Further, according to the present invention, there is provided a damper member manufacturing method capable of easily manufacturing a damper member that exhibits a damper effect and does not cause the damper surface to protrude in the pressure chamber direction and narrow the ink flow path. Can be provided.

1 is an exploded perspective view showing an example of a first embodiment of an inkjet head according to the present invention. Sectional drawing of the inkjet head cut | disconnected along the (ii)-(ii) line | wire in FIG. Cross section of damper member The figure explaining the distance between the ink inlets in the row | line | column of an adjacent pressure chamber The perspective view which shows the one aspect | mode of the damper member which protruded the leg part The figure explaining an example of the manufacturing method of a damper member Sectional drawing which shows an example of 2nd Embodiment of the inkjet head which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment of Inkjet Head)
FIG. 1 is an exploded perspective view showing an example of a first embodiment of an ink jet head according to the present invention. FIG. 2 is a cross-sectional view of the ink jet head taken along line (ii)-(ii) in FIG. 3 is a cross-sectional view of the damper member.

  The inkjet head 1 includes a nozzle plate 11, a head chip 12, a substrate 13, and an ink manifold 14 in order from the bottom in FIG. 1, and these are joined together. A damper member 15 is disposed inside the common ink chamber 141 formed by the internal space of the ink manifold 14.

  The head chip 12 shown in this embodiment has a hexahedral shape, and a plurality of channels 121 which are pressure chambers in the present invention are arranged. Each channel 121 is formed to penetrate straight through the surface of the head chip 12 on the nozzle plate 11 side and the surface of the substrate 13 side. The plurality of channels 121 are arranged in parallel along the X direction in FIG. 1 to form one channel row. A plurality of channel rows are formed in parallel along the Y direction intersecting with the X direction.

  Here, a head chip in which one channel row extending in the X direction is formed by seven channels 121 and four channel rows are arranged in parallel in the Y direction is illustrated. However, the number of channels 121 in one row is not limited in the present invention.

  The channel row (pressure chamber row) is a channel 121 that forms a recording width of an image recorded on the recording material with a predetermined width when the inkjet head 1 and the recording material are relatively moved in one direction. It is a collection of (pressure chambers).

  The recording width is, for example, an image formed when the recording material is conveyed when the inkjet head 1 is fixedly arranged with respect to the recording material and image recording is performed while the recording material is conveyed in one direction. Width. The X direction that is the arrangement direction of the channel rows in the inkjet head 1 is not limited to the direction parallel to the width direction of the recording width of the image formed on the recording material, and may be a direction that obliquely intersects the recording width. .

  The relative movement between the inkjet head 1 and the recording material is not limited to a mode in which the inkjet head 1 is fixedly arranged and the recording material is conveyed, for example, the inkjet head 1 is moved along the width direction of the recording material. An image is recorded by moving the scanning, and the recording material is moved in a direction crossing the scanning movement direction of the inkjet head 1 every scanning movement, or the recording material is fixedly arranged, and the inkjet head 1 is moved to the recording material. For example, an image may be recorded by scanning and moving along the width direction, and the inkjet head 1 may be moved in a direction crossing the scanning movement direction for each scanning movement.

  According to the present invention, it is possible to prevent the influence of crosstalk, in which the pressure wave generated in one channel row, which occurs when the number of channel rows is two or more, affects the adjacent channel row. Also, when an inkjet head having three or more channel rows is used, the pressure wave generated in one channel row affects the adjacent channel rows, so that the influence of crosstalk becomes more prominent There is. Even in the above case, the present invention can be preferably used.

  In the head chip 12, at least a part of a partition wall 122 that partitions between adjacent channels 121 and 121 in each channel row is formed by a polarization-processed piezoelectric element. Drive electrodes (not shown) are formed on both surfaces of each partition wall 122. The partition wall 122 undergoes shear deformation when a drive signal having a predetermined voltage is applied to the drive electrodes on both sides thereof. As a result, the channel 121 sandwiched between the pair of partition walls 122 and 122 changes so that the volume expands and contracts, and applies pressure for ejection to the ink supplied in the channel 121.

  A plurality of nozzles 111 are formed on the nozzle plate 11. Each nozzle 111 communicates with the ink outlet 121 a of the channel 121. The ink in the channel 121 to which the pressure for ejection is applied by the deformation of the partition wall 122 is ejected from the nozzle 111 through the ink outlet 121a. The ink outlet 121a is an opening of the lower channel 121 in FIG.

  The substrate 13 is a flat thin plate having an area larger than the bonding surface with the head chip 12, and is formed of, for example, glass, ceramics, silicon, synthetic resin, or the like. On the surface of the substrate 13 on the head chip 12 side, a wiring (not shown) that is electrically connected to each drive electrode of the head chip 12 is formed. The region of the substrate 13 that protrudes from the head chip 12 functions as a connection portion of an external wiring member (not shown) such as an FPC that electrically connects this wiring and a drive circuit (not shown). .

  Further, a through hole 131 is formed in the substrate 13 in a region where the head chip 12 is bonded, corresponding to the channel 121 of the head chip 12. In the substrate 13 shown in this embodiment, seven through holes 131 are arranged in parallel along the X direction in FIG. 1 to form one row, and four rows are formed along the Y direction. .

  The inside of the channel 121 communicates with the corresponding through hole 131. The opening on the head chip 12 side of the through hole 131 has an area substantially the same as the opening of the channel 121 and is formed to have the same shape as the opening of the channel 121.

  The ink manifold 14 is formed in a box shape whose one surface is open, and is joined to the substrate 13 so as to close the opening. Thus, a common ink chamber 141 that supplies ink in common to all the channels 121 that eject ink is formed in the ink manifold 14. In the common ink chamber 141, ink supplied from an ink inlet (not shown) is stored.

  The ink used in the present invention is not particularly limited. For example, the ink is heated up to a predetermined temperature by a heating means such as a gel UV ink or ceramic ink, and the viscosity of the ink is suitable for ejection. It is preferable to use an ink that needs to be reduced to a minimum. Since such ink is heated to a high temperature during use, gas in a damper member, which will be described later, is likely to expand, and there is a problem of narrowing the ink flow path to the ink inlet 131a. This is because a remarkable effect can be obtained by the invention.

  Each through-hole 131 of the substrate 13 opens toward the common ink chamber 141, and an individual ink flow path that allows the ink in the common ink chamber 141 to flow into the channel 121 between the common ink chamber 141 and the channel 121. Is configured. Therefore, the opening on the common ink chamber 141 side of each through-hole 131 constitutes the ink inlet 131a of the channel 121 corresponding thereto.

  The damper member 15 is disposed in the common ink chamber 141 in the vicinity of the substrate 13. As shown in FIG. 3, the damper member 15 includes a damper frame 151 and a flexible film 152 that functions as a damper surface. In the following, a configuration is shown in which one damper member 15 is disposed inside the common ink chamber 141, but the number is not limited to one, and a plurality of damper members 15 may be disposed. For example, a plurality of damper members may be arranged corresponding to the ink inlet 131a.

  The damper frame 151 is formed in a thin box shape with an opening on the surface on which the flexible film 152 is formed by a member having rigidity. The surface on which the flexible film 152 is formed may be at least on the surface facing the ink inlet 131a. Here, of the hexahedron surfaces, only one surface facing the ink inlet 131a is opened, and the damper frame 151 having the flexible film 152 formed on the surface is illustrated, but the damper member 15 is flexible. You may have two or more surfaces in which a film | membrane is formed.

  It is preferable that at least a part of the damper frame 151 is made of metal. The metal may be used for a part of the wall surface of the damper frame 151, or may form all the wall surfaces. In general, since metal has a higher thermal conductivity than ink (liquid), the temperature distribution of ink in the common ink chamber 141 can be made uniform quickly.

  As the metal, for example, a metal having good thermal conductivity such as aluminum, copper, and stainless steel can be preferably used. Such metal is preferably exposed on the surface of the damper frame 151 so as to be in direct contact with the ink in the common ink chamber 141.

  The flexible membrane 152 is attached so as to close the open surface of the damper frame 151. A damper chamber 153 is constituted by an internal space defined by the damper frame 151 and the flexible film 152. The damper chamber 153 is filled with a gas such as air. In the present invention, when the internal pressure of the damper chamber 153 is set to a negative pressure or at a use temperature at which ink is ejected, the shortest separation distance between the flexible film 152 and the ink inlet 131a is 70 μm or more. The damper member 15 is arranged so that Thus, the damper surface does not protrude in the pressure chamber direction and the ink flow path is not narrowed while exhibiting the damper effect.

  First, the case where the pressure inside the damper chamber 153 is a negative pressure will be described in detail below.

  The internal pressure of the damper chamber 153 in the damper member 15 will be described. The damper chamber 153 having a negative pressure indicates that the internal pressure of the damper member 15 is a negative pressure at room temperature (25 ° C.) compared to the atmospheric pressure.

  Since the damper chamber 153 in the damper member 15 is set to a negative pressure in this way, when the ink in the common ink chamber 141 is heated up to the use temperature and the gas in the damper chamber 153 expands, the flexibility is increased. It is possible to prevent the film 152 from protruding toward the ink inlet 131a. For this reason, even when the inkjet head 1 is driven, as shown in FIG. 2, the ink flow path 141 b for allowing ink to flow into each ink inlet 131 a between the flexible film 152 of the damper member 15 and the substrate 13. Can be secured. The damper member 15 does not hinder the inflow of ink into each channel 121. That is, the damper member 15 exhibits a damper effect even when high-temperature ink is used, and the flexible film 152 serving as a damper surface does not protrude in the direction of the channel 121 and narrow the ink flow path.

  The specific pressure of the damper chamber 153 in the damper member 15 is not particularly limited as long as the negative pressure is obtained as described above in a state where gas is sealed inside. If the pressure is reduced to 50 kPa or more and less than atmospheric pressure at room temperature (25 ° C.) and 1 atmosphere, the flexible film 152 may narrow the ink flow path while exhibiting the damper effect. This is preferable from the viewpoint of obtaining a satisfactory effect. Moreover, the atmospheric pressure in the above-mentioned is an atmospheric pressure that becomes 1 atm when measured under normal temperature (25 ° C.) and 1 atm.

  In addition, as a specific method for measuring the pressure in the damper chamber 153 in the damper member 15, various methods can be used. For example, the following method can be given.

  A thin tube such as an injection needle is attached to the tip of the pressure gauge, and this tube is inserted into the flexible film 152 of the damper member 15 so as not to leak out the gas, and the inside of the tube communicates with the inside of the damper chamber 153. Let At this time, the pressure of the gas acting on the pressure gauge through the inside of the pipe is directly measured. According to this method, even if the differential pressure between the atmospheric pressure and the internal pressure of the damper chamber 153 is small, the internal pressure can be measured finely by the pressure gauge. In addition, when inserting the thin pipe | tube mentioned above in the flexible film | membrane 152 of the damper member 15, the flexible film | membrane 152 may tear and internal gas may leak out. In that case, the place to be inserted in advance is provided on the flexible film 152 so as to surround the periphery with a resin such as an adhesive, and then the above-described thin tube is inserted to suppress the tearing of the flexible film 152. .

  Next, in the following, the case where the damper member 153 is arranged so that the shortest separation distance between the flexible film 152 and the ink inlet is 70 μm or more when the ink is at the operating temperature for discharging ink will be described in detail. .

  From the viewpoint of satisfactorily supplying ink from the common ink chamber 141 to the ink inlet 131a, the shortest separation distance D () between the at least one ink inlet 131a and the flexible film 152 of the damper member 15 at the operating temperature at which ink is discharged. The damper member is arranged so that (see FIG. 2) becomes 70 μm or more. With the above-described configuration, when the ink in the common ink chamber 141 is heated to the operating temperature and the gas in the damper chamber 153 expands, even if the flexible film 152 protrudes toward the ink inlet 131a, at least one ink inlet 131a. And the shortest separation distance D (see FIG. 2) between the damper member 15 and the flexible film 152 of the damper member 15 can be set to 70 μm or more. For this reason, even when the inkjet head 1 is driven, as shown in FIG. 2, the ink flow path 141 b for allowing ink to flow into each ink inlet 131 a between the flexible film 152 of the damper member 15 and the substrate 13. Can be secured. Therefore, even when high temperature ink is used, the damper member 15 does not hinder the inflow of ink into each channel 121.

  The operating temperature at which ink is ejected is the temperature of ink in the common ink chamber 141 when ink is ejected from the nozzle 111, and is higher than room temperature (25 ° C.). As a means for bringing the ink in the common ink chamber 141 to the operating temperature, for example, although not shown, a heater is provided on the surface of the manifold 14 or in the common ink chamber 141 to directly heat the ink in the common ink chamber 141. The ink in the ink tank is heated by a heater, and the heater in the supply pipe for supplying ink to the inkjet head 1 is provided to supply ink to the common ink chamber 141 by supplying the ink in the heated ink tank. One of the means for supplying the ink heated in the process to the common ink chamber 141 or a combination of two or more means may be mentioned.

  Even if no means for heating the ink is provided as described above, the ink-jet head 1 generates a considerable amount of heat when the piezoelectric element is driven. Accordingly, the ink in the common ink chamber 141 may be brought to the use temperature due to the heat generated by the piezoelectric element.

  As the flexible film 152, a synthetic resin film or the like can be used. Examples of the synthetic resin include PI (polyimide), LCP (liquid crystal polymer), PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), and the like. The thickness of the flexible film 152 is not particularly limited, but is preferably 50 μm or more and 150 μm or less from the viewpoint of effectively exhibiting the damper effect by the flexible film 152.

  The damper member 15 is disposed in the common ink chamber 141 so that the surface to which the flexible film 152 is attached faces the substrate 13. As a result, the flexible film 152 of the damper member 15 faces the ink inlet 131 a of the through hole 131 that opens in the substrate 13.

  The planar shape of the damper member 15 is formed in a rectangular shape, but may be any shape such as a circular shape, an elliptical shape, or a polygonal shape. The size of the damper member 15 is smaller than the opening area of the ink manifold 14. Therefore, as shown in FIG. 2, an ink flow path 141 a to the ink inlet 131 a is formed between the periphery of the damper member 15 and the inner wall surface of the common ink chamber 141.

  Note that when the internal pressure of the damper chamber 153 is set to a negative pressure, or at a use temperature at which ink is discharged, the damper is set so that the shortest separation distance D between the flexible film 152 and the ink inlet 131a is 70 μm or more. In any case where the member 153 is disposed, an ink flow path 141 b for allowing ink to flow into each ink inlet 131 a is secured between the flexible film 152 of the damper member 15 and the substrate 13. From the viewpoint of favorably preventing the member 15 from inhibiting the inflow of ink into each channel 121, the flexible film 152 of the damper member 15 is at a use temperature at which the ink in the common ink chamber 141 is discharged. It is preferable to form a flat surface or a surface recessed in the direction opposite to the ink inlet 131a. Further, from the viewpoint of favorably preventing the damper member 15 from obstructing the inflow of ink into each channel 121, a flat surface or a surface recessed in the direction opposite to the ink inlet 131a is formed at room temperature (25 ° C.). More preferably.

  Further, in the common ink chamber 141, the damper member 15 has a separation distance D between at least one ink inlet 131a and the flexible film 152 of the damper member 15 so as to communicate with the ink inlet 131a and the ink inlet 131a. More preferably, it is arranged at a position smaller than the distance between the ink inlet 131a in the channel row adjacent to the channel row including the channel 121 to be performed. The adjacent channel column is a channel column adjacent in the Y direction in FIG.

  The separation distance D is a vertical distance from the ink inlet 131a toward the flexible film 152 of the damper member 152. The separation distance D is D <d1, D <d2, and D <, where d1, d2, and d3 (see FIG. 4) are the distances between the ink inlets 131a in adjacent channel rows in the transport direction. d3 is preferable.

  That is, the damper member 15 is such that the separation distance D is smaller than the distances d1, d2, and d3 in comparison with any of the distances d1, d2, and d3 between the ink inlets 131a and 131a of adjacent channel rows. It is preferable that they are arranged in the common ink chamber 141. At this time, when the damper member 15 is viewed from the ink inlet 131a, the distance to the flexible film 152 of the damper member 15 is closer than the distance to the ink inlet 131a of the adjacent channel row.

  The distances d1, d2, and d3 are the ink inlets in one channel row (hereinafter referred to as ink inlet A) and the ink inlets closest to the ink inlet A in the adjacent channel row (this is referred to as “ink inlet A”). The shortest distance from the ink inlet B). The distances d1, d2, and d3 are generally the widths of the inter-column gaps formed between the ink inlets A and B of adjacent channel columns as shown in FIG. The distances d1, d2, and d3 may not be the same value.

  By arranging the damper member 15 in the common ink chamber 141 as described above, the component of the pressure wave propagating from the channel 121 through the ink inlet 131a into the common ink chamber 141 and traveling straight toward the damper member 15 is provided. Can immediately collide with the flexible film 152 to exert a damper effect. The pressure wave colliding with the flexible film 152 is absorbed by the flexible film 152 being bent and deformed by the compression of the gas sealed in the damper chamber 153. At this time, the linear distance from the ink inlet 131a to the flexible film 152 defined by the separation distance D is shorter than the distance from the ink inlet 131a in the adjacent row, so that it propagates from the ink inlet 131a into the common ink chamber 141. The pressure wave is absorbed by the flexible film 152 before reaching the ink inlet 131a in the adjacent row.

  Therefore, the tamper member 15 absorbs and reduces the pressure wave propagating from the ink inlet 131 a into the common ink chamber 141 before reaching the ink inlet 131 a of the adjacent channel row, and communicates via the common ink chamber 141. It is possible to reduce the influence of crosstalk on the channel 121 of the adjacent channel row.

  In the ink jet head 1 shown in the present embodiment, the ink inlet 131a, the ink outlet 121a, and the nozzle 111 are arranged in a straight line as shown by a straight line L shown by a broken line in FIG. 2, and the straight line L intersects the damper member 15. ing. According to this configuration, since the component of the pressure wave generated in the channel 121 and directed toward the ink inlet 131a can be directly absorbed by the damper member 15, the pressure wave absorption effect is the highest and the effect of reducing the influence of crosstalk is reduced. It is preferable because it is remarkably obtained.

  There is no particular limitation on the means for disposing the damper member 15 at a predetermined distance D from the ink inlet 131a. For example, as shown in FIG. 5, an appropriate number of leg portions 154 may be protruded from the surface of the damper member 15 on the flexible film 152 side. If the leg portions 154 are brought into contact with the substrate 13, the separation distance D can be easily defined by the protruding height of the leg portions 154. The leg portion may be provided on the side surface of the damper frame 151 or may be provided on the substrate 13 side.

  In addition, although not shown, a support may be bridged between the damper member 15 and the inner wall surface of the common ink chamber 141 so that the damper member 15 is supported at a predetermined distance D from the substrate 13.

  By the way, the damper member 15 shown in this embodiment is formed in a size that can cover the ink inlets 131 a of all the through holes 131 formed in the substrate 13 by the flexible film 152. That is, as shown in FIG. 1, when the damper member 15 is projected onto the surface 13a from a direction perpendicular to the surface 13a of the substrate 13 where the ink inlet 131a exists, the damper member 15 includes all of the ink inlet 131a. doing. Thereby, the pressure wave from all the channels 121 can be attenuated by the damper member 15. Further, variation in pressure wave absorption performance for each channel 121 can be reduced. For this reason, this is a preferable mode because the effect of reducing the influence of crosstalk and the influence of temperature distribution can be made uniform among the channels 121.

  At this time, the damper member 15 assumes that the flexible film 152 is a flat surface, and if the flexible film 15 is parallel to the surface 13a of the substrate 13, the dampers 15 are evenly distributed to all the channels 121. It is more preferable because the effect can be exhibited.

  However, in the present invention, the damper member 15 includes a channel row in which the separation distance D between at least one ink inlet 131a and the flexible film 152 includes the ink inlet 131a and the channel 121 communicating with the ink inlet 131a. If the channel is arranged at a position smaller than the distance from the ink inlet 131 a in the adjacent channel row, the pressure wave from the ink inlet 131 a is attenuated by the damper effect, and the influence of crosstalk on the adjacent channel 121. The effect which reduces can be acquired.

  Of course, it is preferable that the number of ink inlets 131a at which the pressure wave is attenuated before reaching the adjacent ink inlet 131a by the damper member 15 is larger. That is, the number of ink inlets 131a arranged so that the distance D between the ink inlet 131a and the flexible film 152 of the damper member 15 is smaller than the distance between the ink inlet 131a in the adjacent channel row. It is preferable from the viewpoint of reducing the influence of the crosstalk that the damper member 15 is disposed so that the ratio of the above becomes 90% or more of the total number of the ink inlets 131a.

  In addition, when the flexible film 152 of the damper member 15 forms a curved surface that is recessed even under an environment where the ink is discharged, the separation distance D between the ink inlet 131a and the flexible film 152 is It is preferably defined by the distance between the most recessed portion of the flexible film 152 and the ink inlet 131a closest to this portion. This makes any ink inlet 131a closer to the flexible membrane 152 than the distance between the ink inlet 131a of the adjacent channel column and reduces the effects of crosstalk between adjacent columns. The effect can be obtained more remarkably.

(Damper member manufacturing method)
Next, an example of a method for manufacturing the damper member 15 in which the internal pressure becomes negative will be described.

  The damper member 15 is manufactured through a negative pressure forming step in which the pressure in the internal damper chamber 153 defined by the damper frame 151 and the flexible film 152 is negative.

  As an example of the negative pressure forming step, as shown in FIG. 6, the damper frame 151 and the flat surface are flattened in the decompression chamber 100 decompressed so that the inside becomes a predetermined pressure (the pressure of the target damper chamber 153). A step of bonding the flexible film 152 to the shape.

  That is, in the decompression chamber 100 decompressed to a predetermined pressure, the flexible film 152 is bonded to the opening surface 151a of the damper frame 151 so as to close the opening surface 151a. Thus, the damper member 15 in which the decompressed gas in the decompression chamber 100 is sealed in the interior damper chamber 153 defined by the damper frame 151 and the flexible film 152, and the interior pressure becomes negative pressure is obtained. Can do.

  The flexible film 152 can be attached using an adhesive or a double-sided tape. When bonding with an adhesive, the adhesive is cured in the vacuum chamber 100 in a reduced pressure state. In addition, in the case of attaching with a double-sided tape, it may be taken out from the decompression chamber 100 after being attached.

  The damper member 15 taken out from the decompression chamber 100 to the atmospheric pressure forms a curved surface in which the flexible film 152 is recessed due to the negative pressure of the damper chamber 153. After the damper member 15 is disposed in the common ink chamber 141 of the inkjet head 1, the gas in the damper chamber 153 expands when the temperature of the ink in the common ink chamber 141 is increased to the use temperature. The expanded flexible film 152 protrudes according to the degree of negative pressure in the damper chamber 153 and the degree of flexibility of the flexible film 152, and forms a flat surface or a concave curved surface.

  According to this method, the damper member 15 in which the damper chamber 153 is set to a predetermined negative pressure can be easily manufactured. Since the negative pressure is defined by the pressure in the decompression chamber 100, even when the damper member 15 is mass-produced, it is possible to produce a homogeneous damper member 15 in which the pressure in the damper chamber 153 does not vary.

  The negative pressure forming step can also be performed under atmospheric pressure without using the decompression chamber 100 as described above.

  For example, although not shown, an adhesive is applied to the peripheral edge of the opening surface 151a of the damper frame 151 to form an adhesive layer, and then the flexible film 152 is bonded. Then, before the adhesive layer is cured, a hollow fine tube member such as an injection needle is inserted into the adhesive layer between the damper frame 151 and the flexible film 152, and an appropriate syringe or suction pump is used. Using the decompression means, the internal gas defined by the damper frame 151 and the flexible membrane 152 is drawn through the tube member. Thereby, the damper chamber 153 can be made into a negative pressure. If the pipe member is pulled out after drawing a predetermined amount of gas, the adhesive layer before curing flows to close the hole by the pipe member, and the negative pressure gas is sealed in the damper chamber 153.

  According to this method, since a large-scale apparatus such as a decompression chamber is not required, it can be manufactured more easily.

(Second Embodiment of Inkjet Head)
FIG. 7 is a sectional view showing an example of the second embodiment of the inkjet head according to the present invention.

  In the inkjet head 2, a head substrate 21 and a wiring substrate 22 are laminated and integrated by an adhesive resin layer 23. A box-shaped ink manifold 24 similar to the ink manifold 14 described above is joined to the upper surface of the wiring board 22. A common ink chamber 241 in which ink is stored is formed between the ink manifold 24 and the wiring board 22. A damper member 25 is disposed in the common ink chamber 241.

The head substrate 21 includes, from the lower side in the figure, a nozzle plate 211 formed of a Si (silicon) substrate, an intermediate plate 212 formed of a glass substrate, a pressure chamber plate 213 formed of a Si (silicon) substrate, and SiO _2. It has a diaphragm 214 formed of a thin film. A nozzle 211 a is opened on the lower surface of the nozzle plate 211.

  The pressure chamber plate 213 is formed with a pressure chamber 213a that stores ink. The upper wall of the pressure chamber 213 a is configured by the diaphragm 214, and the lower wall is configured by the intermediate plate 212. The intermediate plate 212 is formed with a communication passage 212a through which the inside of the pressure chamber 213a communicates with the nozzle 211a.

  On the upper surface of the diaphragm 214, actuators 215 are stacked in a one-to-one correspondence with the pressure chambers 213a. The actuator 215 has a structure in which an actuator body made of a piezoelectric element such as a thin film PZT is sandwiched between an upper electrode and a lower electrode as drive electrodes, and the lower electrode side is disposed on the upper surface of the diaphragm 214. .

  The wiring board 22 is a board on which wiring for applying a drive signal of a predetermined voltage to each actuator 215 is formed, and an external wiring member 26 such as an FPC is provided at an end portion of the wiring board 22 with an ACF (anisotropic conductive film). Are electrically connected.

  The adhesive resin layer 23 is formed of, for example, a thermosetting photosensitive adhesive resin sheet, and is interposed between the head substrate 21 and the wiring substrate 22 so that the substrates 21 and 22 are laminated and integrated. The adhesive resin layer 23 provides an interval corresponding to the thickness of the adhesive resin layer 23 between the substrates 21 and 22. In the adhesive resin layer 23, the actuator 215 and the area corresponding to the periphery thereof are removed by exposure and development. Each actuator 215 is accommodated in the space from which the adhesive resin layer 23 is removed.

  In the adhesive resin layer 23, through holes 231 penetrating vertically are formed corresponding to the number of the pressure chambers 213a. One end (upper end) of each through-hole 231 communicates with the ink supply path 221 formed in the wiring substrate 22, and the other end (lower end) passes through the opening 214 a formed in the vibration plate 214 and is inside the pressure chamber 213 a. Communicated with. The ink supply path 221 opens on the upper surface of the wiring board 22. The opening faces the common ink chamber 241 and functions as an ink inlet 221a that supplies the ink in the common ink chamber 241 into each pressure chamber 213a.

  In the inkjet head 2, ink is supplied from the common ink chamber 241 to the pressure chamber 213a through the ink inlet 221a. When a driving signal is applied from the external wiring member 26 to the actuator 215, the vibration plate 214 is vibrated by the deformation operation of the actuator 215, and a pressure change for discharge is applied to the pressure chamber 213a. The ink inside is discharged from the nozzle 211a through the communication path 212a.

  This inkjet head 2 forms a row of pressure chambers 213a by arranging a plurality of pressure chambers 213a in parallel, and a plurality of rows, preferably three or more rows of pressure chambers 213a are arranged. A chamber 213a is provided. Therefore, the ink inlets 221 a corresponding to the pressure chambers 213 a in each row face the common ink chamber 241.

  The damper member 25 has a damper frame 251 and a flexible film 252, as in the case of the damper member 15 in the first embodiment described above, and is defined by the interior defined by the damper frame 251 and the flexible film 252. A damper chamber 253 is formed. The pressure in the damper chamber 253 is set to a negative pressure. Since the specific structure of the other damper member 25 is the same as that of the damper member 15 described above, the description of the damper member 15 in the first embodiment is used for details thereof, and is omitted here.

  In the damper member 25, as in the above-described damper member 15, the separation distance between at least one ink inlet 221a and the flexible film 252 is a channel that communicates with the ink inlet 131a and the ink inlet 131a. It can be arranged at a position smaller than the distance between the ink inlet 131a in the channel row adjacent to the channel row including 121.

  Similarly to the above-described damper member 15, the damper member 25 has a separation distance between the flexible film 252 and the ink inlet 221a of 70 μm or more when the damper member 25 is at a use temperature for discharging the ink in the common ink chamber 241. It can also be arranged.

  Also in the inkjet head 2, when the actuator 215 is operated, a pressure wave is generated in the pressure chamber 213a, and a part of the pressure wave propagates from the ink inlet 221a into the common ink chamber 241. However, since the pressure wave propagated in the common ink chamber 241 can be absorbed by the damper member 25 before reaching the ink inlet 221a in the adjacent row, the pressure wave is absorbed in the pressure chamber 213a in the adjacent row. It is possible to reduce the influence of crosstalk that has an effect. At this time, since the pressure of the damper chamber 253 in the damper member 25 is a negative pressure, the flexible film 252 exhibits the damper effect while using high-temperature ink, as in the inkjet head 1 in the first embodiment. There is an effect that the ink flow path is not narrowed by protruding in the direction of the pressure chamber 213a.

1: Inkjet head 11: Nozzle plate 111: Nozzle 12: Head chip 121: Channel (pressure chamber)
121a: ink outlet 122: partition wall 13: substrate 13a: surface 131: through hole 131a: ink inlet 14: ink manifold 141: common ink chamber 141a: ink flow path 142: rear inner wall surface 15: damper member 151: damper frame 151a: Opening surface 152: Flexible membrane 153: Damper chamber 154: Leg portion 2: Inkjet head 21: Head substrate 211: Nozzle plate 211a: Nozzle 212: Intermediate plate 212a: Communication passage 213: Pressure chamber plate 213a: Pressure chamber 214: Vibration Plate 214a: Opening 215: Actuator 22: Wiring board 221: Ink supply path 221a: Ink inlet 23: Adhesive resin layer 231: Through hole 24: Ink manifold 241: Common ink chamber 25: Damper member 251: Damper frame 252: the flexible film 253: damper chamber 26: external wiring member 100: vacuum chamber

Claims (12)

Pressure chambers arranged in two or more rows;
A common ink chamber communicating with the pressure chamber via an ink inlet of the pressure chamber;
A damper member in the common ink chamber,
The damper member includes a damper frame and a flexible film, and at least a surface of the damper frame facing the ink inlet is formed by the flexible film, and is defined by the damper frame and the flexible film. An inkjet head characterized in that the internal pressure is a negative pressure.   The separation distance between the ink inlet and the flexible film is a distance between the ink inlet and the ink inlet in the row of the pressure chambers adjacent to the row including the pressure chamber communicating with the ink inlet. The ink jet head according to claim 1, wherein the ink jet head is disposed at a position smaller than the ink jet head.   The separation distance between the ink inlet and the flexible film is a distance between the ink inlet and the ink inlet in the row of the pressure chambers adjacent to the row including the pressure chamber communicating with the ink inlet. The inkjet head according to claim 2, wherein a ratio of the number of the ink inlets arranged at a position smaller than 90% is equal to or more than 90% of the number of all the ink inlets.   4. The ink jet head according to claim 1, wherein the thickness of the flexible film is 10 [mu] m or more and 150 [mu] m or less.   5. The ink jet according to claim 1, wherein an internal pressure defined by the damper frame and the flexible film is reduced so as to be 50 kPa or more and less than atmospheric pressure at room temperature. head.   6. The damper according to claim 1, wherein the damper member includes the ink inlets of all the pressure chambers when the damper member is projected from a direction perpendicular to a surface where the ink inlet is present. An ink jet head according to claim 1.   The flexible film of the damper member forms a flat surface or a recessed surface when at a use temperature at which ink in the common ink chamber is discharged. The inkjet head described in 1.   The inkjet head according to claim 1, wherein the flexible film of the damper member forms a flat surface or a recessed surface at room temperature.   The inkjet head according to claim 1, wherein at least a part of the damper frame is made of metal. Pressure chambers arranged in two or more rows;
A common ink chamber communicating with the pressure chamber via an ink inlet to the pressure chamber;
A damper member in the common ink chamber,
The damper member is a method of manufacturing the damper member in an ink jet head having a damper frame and a flexible film, and at least a surface of the damper frame facing the ink inlet is formed by the flexible film,
A method for producing a damper member, comprising: a negative pressure forming step in which an internal pressure defined by the damper frame and the flexible film is negative. In the negative pressure forming step, the internal pressure defined by the damper frame and the flexible film is reduced by bonding the flexible film to the damper frame in a vacuum chamber that has been reduced to a predetermined pressure. The method for manufacturing a damper member according to claim 10 , wherein a negative pressure is applied. In the negative pressure forming step, after the flexible film is bonded to the damper frame via an adhesive layer, a hollow tube member is inserted into the adhesive layer, and the damper frame and the flexible film define the flexible film. The method for manufacturing a damper member according to claim 10 , wherein the internal pressure is made negative by drawing the internal gas to be drawn through the pipe member.

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