JP2008044298A - Hollow structure, head unit, and inkjet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for favorably connecting a hollow needle designed for an industrial use to a filter assembly. <P>SOLUTION: A hollow structure of a member comprises a first tubular flow path where a liquid flows penetrates through, and a second tubular flow path where a liquid flows through, and the first and second tubular paths are connected by ultrasonic welding to constitute one flow path. The hollow structure is also provided with: a flange portion having an upper surface and a bottom with a horn for ultrasonic welding abutted on the upper surface, and the bottom facing the member; a protrusion positioned on the bottom and having an annular shape surrounding a cross section of the first tubular flow path and to be melted when vibration is given from the horn, and to be closely attached to the bottom and the member; and an annular groove provided in the bottom and surrounding the cross section of the first tubular path, along a virtual closed curve positioned between the protrusion and the cross section. The cross section of bottom of the annular groove is arched. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hollow structure, and more particularly to a hollow structure suitably used in a head unit of an ink jet apparatus.

  Patent Document 1 discloses a head unit for consumer use. The head unit includes a head, a filter assembly, and a hollow needle. The filter assembly includes a filter made of SUS mesh. Since ink passes through the filter before being supplied to the inkjet head, the inflow of dust into the inkjet head is prevented. Here, the hollow needle and the filter assembly are connected to each other by ultrasonic welding.

Japanese Patent Laid-Open No. 6-336034 (FIG. 6 etc.)

  When the head unit is used in industrial applications, the liquid flowing in the head unit is not limited to water-based ink, unlike when used in consumer applications. For this reason, PPS (polyphenyl sulfide) is used as a material for a member that defines a flow path through which ink flows so that the head unit is applied even for industrial use. PPS is a crystalline resin and is therefore chemically stable against industrial liquids flowing through the head unit. Here, the member that defines the flow path through which the ink flows is, for example, the hollow needle described above.

  However, hollow needles made of PPS are relatively difficult to melt during ultrasonic welding. For this reason, when connecting the hollow needle and the filter assembly by ultrasonic welding, it is necessary to apply more energy to the hollow needle. As a result, the structure of the hollow needle may be partially destroyed by the vibration for ultrasonic welding. Specifically, as shown in FIG. 6 of Patent Document 1, the hollow needle is provided with an annular groove that accommodates an extra molten component at the time of ultrasonic welding, and the annular groove is caused by vibration of ultrasonic welding. Cracks starting from may occur.

  The present invention has been made in view of the above problems, and one of its purposes is to satisfactorily connect a hollow needle designed for industrial use to a filter assembly.

  According to an aspect of the present invention, the first tubular flow path through which the liquid material passes and the first tubular flow path through which the liquid material flows pass through the first tubular flow path. A hollow structure in which the tubular flow channel and the second tubular flow channel are connected by ultrasonic welding so as to form one flow channel has an upper surface and a bottom surface facing each other, and the super structure is disposed on the upper surface. A horn for sonic welding is brought into contact, and the bottom surface is located on the bottom surface facing the member and the bottom surface, and has an annular shape surrounding the cross section of the first tubular channel. A projection that melts when a vibration is applied from the horn and forms a welded layer that is in close contact with the bottom surface and the member; and the cross section of the first tubular channel is provided on the bottom surface. Surrounding and located between the protrusion and the cross section And a, an annular groove along the virtual closed curve. And the cross section of the bottom part of the said annular groove has comprised the arch-shaped curve.

  According to the said structure, the cross section of the annular groove of a bottom face has comprised the arch-shaped curve. For this reason, even if a horn is brought into contact with the upper surface facing the bottom surface and vibration is applied to the flange portion, cracks starting from the annular groove are unlikely to occur.

  According to an aspect of the present invention, the first tubular flow path through which the liquid material passes and the first tubular flow path through which the liquid material flows pass through the first tubular flow path. A hollow structure in which the tubular flow channel and the second tubular flow channel are connected by ultrasonic welding so as to form one flow channel has an upper surface and a bottom surface facing each other, and the super structure is disposed on the upper surface. A horn for sonic welding is brought into contact, and the bottom surface is located on the bottom surface facing the member and the bottom surface, and has an annular shape surrounding the cross section of the first tubular channel. A projection that melts when a vibration is applied from the horn and forms a welded layer that is in close contact with the bottom surface and the member; and the cross section of the first tubular channel is provided on the bottom surface. And surrounds the protrusion and the cross section. It includes a plurality of grooves formed discretely along a virtual closed curve, a.

  According to the above configuration, the plurality of grooves are discretely arranged on the bottom surface. For this reason, even if a horn is brought into contact with the upper surface opposite to the bottom surface and vibration is applied to the flange portion, cracks starting from the plurality of grooves are unlikely to occur.

  According to another aspect of the invention, a cross section of at least one bottom of the plurality of grooves forms an arched curve.

  According to the above configuration, the cross section of at least one bottom of the plurality of grooves forms an arched curve. For this reason, even if the horn is brought into contact with the upper surface facing the bottom surface and vibration is applied to the flange portion, cracks starting from a plurality of grooves are less likely to occur.

  Furthermore, according to another aspect of the present invention, a head unit for an ink jet apparatus includes: a filter assembly through which a first tubular flow path through which a liquid material passes; and a second tubular flow path through which the liquid material flows. A hollow needle that penetrates and is connected to the filter assembly by ultrasonic welding so that the first tubular flow channel and the second tubular flow channel constitute one flow channel. Yes. The hollow needle is located on the bottom surface, and a flange portion having a top surface with which the ultrasonic welding horn contacts, a bottom surface facing the top surface and facing the filter assembly. And a projecting portion that has an annular shape surrounding the cross section of the second tubular flow channel, and that melts when vibration is applied from the horn to form a weld layer that is in close contact with the bottom surface and the filter assembly. And an annular groove that surrounds the cross section of the second tubular flow channel and that extends along a closed curve located between the protrusion and the cross section. Further, the cross section of the bottom of the annular groove has an arched curve.

  Furthermore, according to an aspect of the present invention, a head unit for an ink jet apparatus includes a filter assembly in which a first tubular flow path through which a liquid passes and a second tubular flow path through which the liquid passes. And a hollow needle connected to the filter assembly by ultrasonic welding so that the first tubular flow path and the second tubular flow path constitute one flow path. . The hollow needle is located on the bottom surface, and a flange portion having a top surface with which the ultrasonic welding horn contacts, a bottom surface facing the top surface and facing the filter assembly. And a projecting portion that has an annular shape surrounding the cross section of the second tubular flow channel, and that melts when vibration is applied from the horn to form a weld layer that is in close contact with the bottom surface and the filter assembly. And a plurality of discretely provided along a virtual closed curve located between the protrusion and the cross-section, which is provided on the bottom surface and surrounds the cross-section of the second tubular channel. And a groove.

  Here, a cross section of at least one bottom of the plurality of grooves may form an arched curve. Further, the ink jet apparatus may include the above-described head unit.

  The head unit 1 of FIG. 1 includes two hollow needles 2, a filter assembly 3, an ink jet head 4, a substrate 5, and two bushes 51. Each of the two hollow needles 2 is connected to a filter assembly 3. On the other hand, the two bushes 51 are located between the filter assembly 3 and the substrate 5. Here, the substrate 5 is positioned between the filter assembly 3 and the inkjet head 4 and supports the filter assembly 3 and the inkjet head 4. As will be described in detail later, in the head unit 1, two flow paths that pass through the filter assembly 3, each of the two bushes 51, and the substrate 5 and reach from the two hollow needles 2 to the inkjet head 4 are formed. Is formed.

  As will be described later, the liquid material is supplied from each of the two tubes 7 to the head unit 1 having such a configuration. The hollow needle is an example of a “hollow structure” described at the end of the present specification.

  Incidentally, the head unit 1 of the present embodiment is included in an ink jet apparatus. The inkjet device corresponds to, for example, a consumer inkjet printer, a medical inkjet device, or an industrial inkjet device. In the ink jet apparatus, different liquid materials depending on the application can be supplied to the hollow needle 2 and discharged from the ink jet head 4. In FIG. 8, an industrial inkjet apparatus 100 is schematically illustrated as an example.

  Below, the filter assembly 3 and the hollow needle 2 are demonstrated in this order.

(A. Filter assembly)
As shown in FIGS. 2A and 2B, the filter assembly 3 includes an upper surface 3a, a lower surface 3b, a side surface 3c surrounding the upper surface 3a and the lower surface 3b, and a filter 31 described later. ing. And the filter assembly 3 borders the tubular flow path 33 which penetrates the filter assembly 3 itself. Furthermore, a part of the upper surface 3a constitutes a recess 30 that receives the flange portion 21a (see FIG. 3) of the hollow needle 2. The recessed portion 30 has a circumferential band-shaped stepped portion 30a corresponding to the bottom surface 21c (see FIG. 3) of the flange portion 21a inside, and the stepped portion 30a borders the inlet portion 34 of the tubular flow path 33. taking it.

  The filter 31 is a mesh made of SUS and is positioned so as to cover the inlet portion 34. The filter 31 allows the liquid material to pass but does not allow the dust to pass. Thanks to this filter 31, dust existing inside the tube 7 (FIG. 1) connected to the hollow needle 2 is stopped. In order to prevent the inflow of dust into the inkjet head 4, it is preferable that the filter 31 is located at a position closer to the inkjet head 4 as in the present embodiment. By doing so, the probability that dust will flow into the inkjet head 4 is reduced.

  A part of the lower surface 3 b of the filter assembly 3 borders the outlet portion 35 of the tubular flow path 33. A bush 51 (FIG. 1) is in contact with the outlet portion 35 of the tubular flow path 33. The bush 51 functions as an inlet portion of a tubular channel that passes through the substrate 5 and communicates with the inside of the inkjet head 4. The bush 51 of this embodiment is made of rubber or elastic resin. Such a bush 51 not only allows the liquid material to flow from the filter assembly 3 to the ink jet head 4 side, but also serves to protect the ink jet head 4 by mitigating the impact and vibration applied from the filter assembly 3 side.

(B. Hollow needle)
The hollow needle 2 in FIG. 3 basically has a funnel shape. That is, the hollow needle 2 is configured such that the liquid material flows through the hollow needle 2. However, unlike a normal funnel, the hollow needle 2 is used so that the liquid material flows from the small diameter side to the large diameter side.

  In the present embodiment, the hollow needle 2 is made of a material containing a resin and a reinforcing material that reinforces the resin. The resin in the present embodiment is a crystalline resin, specifically, PPS (polyphenyl sulfide). On the other hand, the reinforcing material is glass fiber. The hollow needle 2 made of such a material is not only stable to a printing liquid, that is, ink, but also stable to an industrial liquid.

  The structure of the hollow needle 2 will be described in more detail. The hollow needle 2 has a distal end portion 20, a bottom portion 21, a side wall portion 22 that surrounds the distal end portion 20 and the bottom portion 21 without a gap, a projection portion 26, and an annular groove 27. Further, the hollow needle 2 borders one tubular channel 23 penetrating the hollow needle 2 itself from the tip 20 toward the bottom 21. Hereinafter, the direction in which the tubular channel 23 extends is also referred to as “channel direction”.

  The cross section perpendicular to the flow path direction of the tubular flow path 23 is substantially a circle. Then, the area of the cross section of the tubular channel 23 increases stepwise or gradually from the tip 20 to the bottom 21. In the present embodiment, the diameter of the tubular channel 23 at the bottom 21 is larger than the inner diameter of the tube 7 (FIG. 1) to be crimped to the tip 20. In addition, when the hollow needle 2 is connected to the filter assembly 3, the bottom 21 of the hollow needle 2 faces the filter 31 side. For this reason, the area of the filter 31 can be made larger than the inner diameter of the tube 7, and the liquid can be passed through almost the entire area of the filter 31. As a result, the flow resistance generated when the liquid passes through the filter 31 can be reduced.

  The distal end portion 20 of the hollow needle 2 borders four introduction holes 24 (one in FIG. 3) that function as inlet portions to one common tubular channel 23. The bottom 21 borders an opening 25 that functions as an outlet of the tubular channel 23. The liquid material supplied from the tube 7 is introduced into the tubular flow path 23 from the four introduction holes 24 of the distal end portion 20. Then, the liquid material exits the tubular channel 23 from the opening 25. The liquid material that has exited the tubular channel 23 passes through the filter 31 in the tubular channel 33 described above.

  The bottom portion 21 of the hollow needle 2 has a flange portion 21a. The flange portion 21a is a portion that protrudes in a direction substantially perpendicular to the flow path direction and has a substantially rotationally symmetric shape with respect to the flow path direction. As shown in FIG. 5, the flange portion 21 a has a size that is just within the range bordered by the concave portion 30 of the filter assembly 3. The position of is determined. Further, when the hollow needle 2 is positioned with respect to the filter assembly 3, the tubular flow path 23 and the tubular flow path 33 are connected to each other.

  Returning to FIG. 3, the flange portion 21a has an upper surface 21b, a bottom surface 21c opposite to the upper surface 21b, and a side surface 21d connecting the upper surface 21b and the bottom surface 21c. The horn 8 (FIG. 5) that performs ultrasonic welding comes into contact with the upper surface 21b. On the other hand, the bottom surface 21 c is a portion facing the stepped portion 30 a side of the filter assembly 3 when the hollow needle 2 is welded to the filter assembly 3. And the protrusion part 26 is located on such a bottom face 21c. Furthermore, the annular groove 27 is provided in such a bottom face 21c.

  As shown in FIG. 4, the protrusion 26 has an annular shape surrounding the cross section of the tubular channel 23. Further, as shown in FIG. 6, the protrusion 26 melts when a vibration is applied from the horn 8 (FIG. 5) in contact with the upper surface 21b, and welds the bottom surface 21c and the stepped portion 30a in close contact with each other. Layer 6 will be formed. And by this welding layer 6, while the hollow needle 2 is connected to the filter assembly 3, it comprises one flow path with which the tubular flow path 23 and the tubular flow path 33 were sealed.

  Returning to FIG. 4, the annular groove 27 is a virtual closed curve surrounding the cross section of the tubular flow path 23, and is a virtual closed curve positioned between the protrusion 26 and the cross section of the tubular flow path 23. It has a shape along. Further, the cross section of the bottom of the annular groove 27 forms an arched curve. Here, the arch-shaped curve is convex on the upper surface 21b side. The arcuate curve corresponds to at least one of a part of an arc, a part of a parabola, a part of a suspension curve, and a combination thereof.

  At the time of ultrasonic welding, a surplus portion of the melt generated by melting the protrusions 26 flows into the annular groove 27. For this reason, thanks to the annular groove 27, there is little possibility of the melt flowing out during ultrasonic welding.

  Now, the thickness of the part corresponding to the annular groove 27 of the flange part 21a is smaller than the thickness of the other part of the flange part 21a. Here, in the case of the conventional hollow needle, at the time of ultrasonic welding, the portion corresponding to the groove may not withstand the vibration of ultrasonic welding, and a crack starting from the groove may occur. On the other hand, according to this embodiment, the cross section of the bottom of the annular groove 27 forms an arched curve. For this reason, even if a vibration of ultrasonic welding is applied, the force is dispersed by the bottom of the annular groove 27, so that cracks starting from the annular groove 27 are unlikely to occur. As a result, the energy of vibration from the horn 8 can be increased, and even the hollow needle 2 made of a material that is difficult to melt by vibration can be connected to the filter assembly 3 satisfactorily.

  In the example of FIG. 3, only the bottom cross section of the annular groove 27 has an arched curve, but the entire cross section of the annular groove 27 may have an arched curve. If it does so, the intensity | strength with respect to a vibration will improve more.

  Furthermore, according to the hollow needle of another embodiment, instead of the annular groove 27, a plurality of discrete grooves may be provided. In the case of a plurality of discrete grooves, it is not essential that the cross section of the bottom of these grooves has an arched curve.

  For example, as shown in FIG. 7, a virtual closed curve surrounding the cross section of the tubular flow path 23, which is along a virtual closed curve positioned between the protrusion 26 and the cross section of the tubular flow path 23. The plurality of grooves 28 may be provided discretely. In the case of FIG. 7, the cross section of each bottom of the plurality of grooves 28 is a straight line. Even in such a case, the portion where the thickness of the flange portion 21a is small is discrete while leaving room for the melt during ultrasonic welding to flow, so that it resists vibration from the horn 8 that is in contact with the upper surface 21b. It is possible. As a result, the generation of cracks starting from the plurality of grooves 28 can be prevented. As a result, the energy of vibration from the horn 8 can be increased. For this reason, even the hollow needle 2 made of a material that does not easily melt due to vibration can be connected to the filter assembly 3 satisfactorily.

  Of course, if the cross section of at least one bottom of the plurality of grooves 28 in FIG. 7 has an arched curve, the strength against vibration is further improved.

  In the above, an example in which the present invention is applied to a hollow needle applied to a head unit for an inkjet apparatus has been described as an example of a hollow structure, but the present invention is not limited to such an example. Specifically, the present invention can be applied to any hollow structure that is made of a material capable of ultrasonic welding and is connected by ultrasonic welding to another member provided with a tubular channel. .

The schematic diagram which shows the head unit of this embodiment. (A) is a perspective view which shows the filter assembly of this embodiment, (b) is a schematic diagram which shows a partial cross section of the filter assembly of (a). The schematic diagram which shows the cross section of the hollow needle of this embodiment. The schematic diagram which shows the bottom part of the hollow needle of FIG. FIG. 4 is a schematic diagram illustrating a state where the hollow needle of FIG. 3 is positioned with respect to the filter assembly of FIG. 2. FIG. 4 is a schematic view showing a state where the hollow needle of FIG. 3 is connected to the filter assembly of FIG. 2. The schematic diagram which shows the modification of the groove | channel of the hollow needle of this embodiment. 1 is a schematic diagram illustrating an inkjet apparatus according to an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Head unit, 2 ... Hollow needle, 3 ... Filter assembly, 3a ... Upper surface, 3b ... Lower surface, 3c ... Side surface, 4 ... Inkjet head, 5 ... Substrate, 6 ... Welded layer, 7 ... Tube, 8 ... Horn, 20 ... tip part, 21 ... bottom part, 21a ... flange part, 21b ... top face, 21c ... bottom face, 21d ... side face, 26 ... projection part, 27 ... annular groove, 28 ... multiple grooves, 22 ... side wall part, 23, 33 ... Tubular flow path, 24 ... introduction hole, 25 ... opening, 30 ... recess, 30a ... step part, 31 ... filter, 33 ... tubular flow path, 34 ... inlet part, 35 ... outlet part, 51 ... bush, 100 ... inkjet apparatus.

Claims (7)

The first tubular flow path and the second tubular flow path with respect to the member through which the first tubular flow path through which the liquid material flows and the second tubular flow path through which the liquid material flows pass. It is a hollow structure connected by ultrasonic welding so that the tubular flow channel constitutes one flow channel,
A flange portion that has an upper surface and a bottom surface facing each other, the ultrasonic welding horn is in contact with the upper surface, and the bottom surface faces the member;
A welding layer located on the bottom surface, having an annular shape surrounding the cross section of the first tubular flow channel, and melted when vibration is applied from the horn, and is in close contact with the bottom surface and the member A protrusion that forms
An annular groove that is provided on the bottom surface and surrounds the cross section of the first tubular flow channel and along a virtual closed curve located between the protrusion and the cross section;
With
The cross section of the bottom of the annular groove has an arched curve,
Hollow structure. The first tubular flow path and the second tubular flow path with respect to the member through which the first tubular flow path through which the liquid material flows and the second tubular flow path through which the liquid material flows pass. It is a hollow structure connected by ultrasonic welding so that the tubular flow channel constitutes one flow channel,
A flange portion that has an upper surface and a bottom surface facing each other, the ultrasonic welding horn is in contact with the upper surface, and the bottom surface faces the member;
A welding layer located on the bottom surface, having an annular shape surrounding the cross section of the first tubular flow channel, and melted when vibration is applied from the horn, and is in close contact with the bottom surface and the member A protrusion that forms
A plurality of grooves provided on the bottom surface and surrounding the cross section of the first tubular channel and discretely provided along a virtual closed curve located between the protrusion and the cross section When,
With hollow structure. The hollow structure according to claim 1,
A cross section of at least one bottom of the plurality of grooves has an arched curve;
Hollow structure. A head unit for an inkjet device,
A filter assembly through which a first tubular flow path through which the liquid flows,
An ultrasonic wave is passed through the filter assembly so that the second tubular flow path through which the liquid material passes and the first tubular flow path and the second tubular flow path form one flow path. Hollow needles connected by welding,
With
The hollow needle is
A flange portion having an upper surface on which the ultrasonic welding horn contacts, and a bottom surface facing the upper surface and facing the filter assembly;
Welding located on the bottom surface, having an annular shape surrounding the cross section of the second tubular flow path, and melted when a vibration is applied from the horn, and is in close contact with the bottom surface and the filter assembly A protrusion forming a layer;
An annular groove that is provided on the bottom surface and surrounds the cross section of the second tubular flow channel and along a closed curve located between the protrusion and the cross section;
The cross section of the bottom of the annular groove has an arched curve;
Head unit. A head unit for an inkjet device,
A filter assembly through which a first tubular flow path through which the liquid flows,
An ultrasonic wave is passed through the filter assembly so that the second tubular flow path through which the liquid material passes and the first tubular flow path and the second tubular flow path form one flow path. Hollow needles connected by welding,
With
The hollow needle is
A flange portion having an upper surface on which the ultrasonic welding horn contacts, and a bottom surface facing the upper surface and facing the filter assembly;
Welding located on the bottom surface, having an annular shape surrounding the cross section of the second tubular flow path, and melted when a vibration is applied from the horn, and is in close contact with the bottom surface and the filter assembly A protrusion forming a layer;
A plurality of grooves provided on the bottom surface and surrounding the cross section of the second tubular flow channel and discretely provided along a virtual closed curve located between the protrusion and the cross section And having
Head unit. The head unit according to claim 5,
A cross section of at least one bottom of the plurality of grooves has an arched curve;
Head unit. An ink jet apparatus comprising the head unit according to claim 4.

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