JP6819040B2 - Manufacturing method of flow path structure, liquid injection head, liquid injection device, flow path structure - Google Patents

Description

The present invention relates to a technique for injecting a liquid such as ink.

Conventionally, a liquid injection head that injects a liquid such as ink from a plurality of nozzles has been proposed. For example, in Patent Document 1, a groove is formed on each facing surface of two substrates, and the two substrates are joined by laser welding around the groove to form a liquid flow path surrounded by a wall surface of the groove. The configuration formed in the injection head is disclosed. Patent Document 1 makes the thickness of the end region thinner than that of other portions in view of the fact that the end region of the welded portion is more likely to escape heat when irradiated with laser light, resulting in insufficient welding. Therefore, the thermal energy of the laser beam is increased in the end region.

Japanese Unexamined Patent Publication No. 2011-104891

By the way, in the flow path formed in the substrate by laser welding, a flow path tube of another flow path communicating with this flow path may be formed so as to protrude from the surface of the substrate. The portion of such a flow path tube that protrudes from the substrate is thicker than the other portion of the substrate. Therefore, when the substrate is welded by irradiating the substrate with laser light from the surface on which the flow path tube protrudes, the protruding portion of the flow path tube is thicker than other parts of the substrate, so that the laser light is compared with other parts. Is likely to be attenuated, so that uneven welding is likely to occur due to insufficient welding. At this time, the laser beam may be applied from the flat flat side where the flow path tube or the like is not projected, but as in recent years, the more complicated the flow path structure and the flow path substrate configuration, the more protrusions from the substrate. Therefore, it may not always be possible to irradiate the laser beam from the flat flat side.

Also in Patent Document 1 described above, a flow path tube forming another flow path communicating with the flow path formed on the substrate protrudes from the substrate. However, there is no description or assumption that the laser beam is applied from the side of the substrate opposite to the side where the flow path tube protrudes, and the laser light is applied from the side where the flow path tube protrudes. Moreover, as in Patent Document 1, when the portion of the flow path tube protruding from the substrate protrudes from the region of the flow path in the substrate in a plan view, the laser beam is tentatively emitted from the side where the flow path tube protrudes. If the welding is performed by applying the above, the laser beam is attenuated at the portion where the flow path tube protrudes, so that uneven welding is likely to occur due to insufficient welding. If such uneven welding between the substrates occurs, the airtightness of the flow path may decrease. In consideration of the above circumstances, an object of the present invention is to reduce welding unevenness due to laser welding.

[Aspect 1]
In order to solve the above problems, the flow path structure according to the preferred aspect (aspect 1) of the present invention is a flow path structure that forms a flow path of a liquid, and has absorbency to laser light. The light absorbing member having the light absorbing member, the light transmitting member joined to the light absorbing member and having transparency to the laser light, and the light absorbing member and the light transmitting member are surrounded by a welded surface. It is provided with one flow path and a second flow path formed in a flow path tube protruding from the surface of the light transmissive member opposite to the welding surface and communicating with the first flow path, from a direction orthogonal to the welding surface. In the plan view of, the flow path tube is included in the region of the first flow path. In the first aspect, since the flow path tube protruding from the surface of the light transmitting member on the opposite side of the welding surface is included in the region of the first flow path in a plan view from the direction orthogonal to the welding surface, the first Since the welding surface surrounding the flow path does not overlap with the tube surface of the flow path tube, uneven welding can be effectively reduced. As a result, a highly airtight flow path can be formed. Further, in the first aspect, since the flow path tube formed in the light transmitting member may be included in the area of the first flow path, it is provided in another flow path tube, for example, a light absorbing member. The degree of freedom of the cross-sectional area of the flow path pipe can be increased.

[Aspect 2]
In a preferred example of the first aspect (aspect 2), the second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path. In the second aspect, since the second flow path includes a diameter-expanded portion having a first tapered portion that extends in a tapered shape toward the downstream side of the first flow path toward the first flow path, the upstream side of the first flow path. Since the liquid flowing from the first to the downstream side can easily flow from the first flow path to the second flow path, the stagnation of the liquid that tends to occur in this portion can be suppressed. This makes it easier to exhaust the air bubbles that stay in the stagnation portion of the liquid, so that the air bubble discharge property can be improved.

[Aspect 3]
In a preferred example of the second aspect (aspect 3), the enlarged diameter portion of the second flow path further has a second tapered portion that tapers toward the upstream side of the first flow path toward the first flow path. The inclination angle of the first tapered portion with respect to the second flow path is larger than the inclination angle of the second tapered portion with respect to the second flow path. In the third aspect, since the diameter-expanded portion of the second flow path has a second tapered portion that extends further to the upstream side in addition to the first tapered portion that extends to the downstream side of the first flow path, the diameter of the second flow path is expanded. Since the cross-sectional area of the portion can be increased, the liquid can be more easily flowed from the first flow path to the second flow path. Further, in the third aspect, since the inclination angle of the first tapered portion extending to the downstream side with respect to the second flow path is larger than the inclination angle of the second tapered portion extending to the upstream side with respect to the second flow path, the first taper Compared with the case where both the portion and the second tapered portion have the same inclination angle, the cross-sectional area of the second flow path can be prevented from becoming too large, so that a decrease in the flow velocity can be suppressed. In this way, the liquid can be made easier to flow from the first flow path to the second flow path while suppressing the decrease in the flow velocity, so that the discharge property of the bubbles can be further improved.

[Aspect 4]
In the preferred example of Aspect 2 or Aspect 3 (Aspect 4), the end of the enlarged diameter portion of the second flow path is open to the surface of the light transmitting member facing the light absorbing member. In the fourth aspect, since the end of the enlarged diameter portion of the second flow path is open on the surface of the light transmitting member facing the light absorbing member, it is easy to form the enlarged diameter portion in the second flow path. ..

[Aspect 5]
In any of the preferred examples (Aspect 5) of Aspects 2 to 4, a plurality of second flow paths are formed from the inlet flow path communicating with the first flow path to the downstream side, and the plurality of second flow paths are the first. The light absorbing member includes a flow path arranged at the downstream end of the 1 flow path and a flow path arranged between the downstream end of the first flow path and the inlet flow path. A protrusion that projects toward the enlarged diameter portion of the flow path at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path among the plurality of second flow paths. The part is formed. In the fifth aspect, the diameter of the second flow path is directed toward the enlarged diameter portion of the second flow path at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path. Since the protruding portion is formed, a flow is generated along the protruding portion of the first flow path and the enlarged diameter portion of the second flow path at the branch point between the first flow path and each of the second flow paths. Therefore, a flow from the first flow path to the second flow path is more likely to be formed. As a result, the stagnation of the liquid at each branch point is suppressed and the bubbles are easily discharged, so that the discharge property of the bubbles at each branch point can be further improved.

[Aspect 6]
In any preferred example of any of aspects 2 through 5, the first flow path is formed from one end to the other, and the inlet flow path is one end and the other. Arranged between the ends, the second flow path is located at both one end and the other end. In aspect 6, the first flow path is formed from one end to the other end, and the inlet flow path is located between one end and the other end, the second flow. Since the roads are arranged at both one end and the other end, the liquid flowing in from the inlet flow path branches and not only the second flow path at one end but also the other end. It becomes easy to flow to the second flow path of. According to this, stagnation of one end and the other end of the first flow path can be suppressed as compared with the case where there is no inlet flow path between one end and the other end. Therefore, it becomes easy to discharge the air bubbles that stay in the stagnation. As a result, uneven welding of laser welding can be reduced while suppressing stagnation of one end and the other end of the first flow path.

[Aspect 7]
In any of the preferred examples (Aspect 7) of Aspects 1 to 6, the first flow is formed in a flow path tube that protrudes on the side opposite to the flow path tube in which the second flow path is formed with respect to the welding surface. The number of flow path pipes having a third flow path communicating with the road and forming the third flow path is smaller than the number of flow path pipes forming the second flow path, and the cross-sectional area of the third flow path is It is larger than the cross-sectional area of the second flow path. In the seventh aspect, since the cross-sectional area of the third flow path is larger than the cross-sectional area of the second flow path, the pressure loss in the flow path can be reduced. In particular, when there are a plurality of second flow paths communicating with the first flow path, pressure loss is likely to occur, so that the effect of reducing this is great. Moreover, the third flow path is formed on the flow path tube that projects on the side opposite to the flow path tube on which the second flow path is formed with respect to the welding surface, that is, on the side opposite to the side that irradiates the laser beam. Therefore, even if the cross-sectional area of the third flow path is increased, the welding unevenness of laser welding can be reduced. As a result, uneven welding of laser welding can be reduced while reducing pressure loss.

[Aspect 8]
In a preferred example of aspect 7 (aspect 8), the outer circumference of the flow path pipe forming the third flow path has a size exceeding the region of the first flow path in a plan view from a direction orthogonal to the welding surface. In the eighth aspect, since the outer circumference of the flow path pipe forming the third flow path has a size exceeding the region of the first flow path in a plan view from a direction orthogonal to the welding surface, the cross-sectional area of the third flow path Can be made larger. Therefore, the effect of reducing the pressure loss in the first flow path can be enhanced.

[Aspect 9]
In a preferred example of aspect 7 or 8 (aspect 9), the light absorbing member comprises two light transmitting members joined to the light absorbing member and transparent to laser light, and the light absorbing member has two light transmitting members. It is sandwiched between the sex members and laminated, and the flow path tube of the second flow path is formed in one or both of the two light transmitting members. In the ninth aspect, since the two light-transmitting members bonded to the light-absorbing member and having transparency to the laser light are provided, the laser light is irradiated from both surfaces of the two light-transmitting members, and 2 Each of the light transmitting members can be welded to the light absorbing member. At this time, since the flow path tube of the second flow path included in the region of the first flow path is formed on one or both of the two light transmissive members, the surface of any of the light transmissive members. Welding unevenness can be reduced even by irradiating with laser light.

[Aspect 10]
In a preferred example of the ninth aspect (aspect 10), the flow path tube of the second flow path is formed in one of the two light transmitting members, and the flow path tube of the third flow path is formed in the other. In the tenth aspect, since the flow path tube of the second flow path is formed in one of the two light transmissive members and the third flow path tube is formed in the other, the cross-sectional area of the third flow path is increased. Since it can be increased, the pressure loss in the first flow path can be reduced. Further, by performing laser welding to join the second substrate and the first substrate on which the flow path tube of the second flow path included in the region of the first flow path is formed, welding unevenness can be reduced. ..

[Aspect 11]
In a preferred example (Aspect 11) of Aspect 9 or Aspect 10, the light absorbing member is provided with a filter interposed between the two light transmitting members. In the eleventh aspect, since the filter interposed between the two light transmitting members is provided in the light absorbing member, the laser light can be measured as compared with the case where the filter is provided in any of the two light transmitting members. Since it is not necessary to arrange the filters so that they do not overlap in the irradiation direction, it is possible to increase the degree of freedom in designing the arrangement and size of the filters.

[Aspect 12]
The liquid injection head according to a preferred aspect (aspect 12) of the present invention injects the flow path structure according to any one of claims 1 to 11 and the liquid from the flow path structure by driving a drive element. It is equipped with a nozzle. In the 12th aspect, since the flow path structure according to any one of claims 1 to 11 is provided, welding unevenness due to laser welding is reduced, so that a liquid injection head in which a highly airtight flow path is formed can be provided. ..

[Aspect 13]
The liquid injection device according to a preferred aspect (aspect 13) of the present invention includes a transfer mechanism for conveying a medium and a liquid injection head according to claim 12, which injects a liquid into the medium. In the thirteenth aspect, since the liquid injection head of claim 12 is provided, welding unevenness due to laser welding is reduced, so that a liquid injection device in which a highly airtight flow path is formed can be provided. A good example of a liquid injection device is a printing device that injects ink onto a medium such as printing paper, but the application of the liquid injection device according to the present invention is not limited to printing.

[Aspect 14]
The method for manufacturing a flow path structure according to a preferred embodiment (aspect 14) of the present invention is a flow path structure for forming a flow path of a liquid, which is a light absorbing member having absorption to laser light. , A step of forming a flow path groove of the first flow path on one or both facing surfaces of a light transmitting member having transparency to laser light, and a light absorbing member in the light transmitting member. A step of forming a flow path tube protruding from the surface opposite to the surface facing the surface, and forming a second flow path communicating with the first flow path in the flow path tube, and a light absorbing member and a light transmitting member. And a welding surface that surrounds the flow path groove without overlapping with the flow path tube in the irradiation direction by irradiating the laser beam toward the light transmissive member and the step of stacking the above so that the opposing surfaces are in contact with each other. The step of forming the first flow path by forming the first flow path is provided. In aspect 14, in the laser beam irradiation direction (including the direction orthogonal to the welding surface or the direction oblique to the welding surface), the welding surface surrounding the first flow path does not overlap the tube surface of the flow path tube, so that welding unevenness occurs. Can be effectively reduced. As a result, a highly airtight flow path can be formed.

[Aspect 15]
In a preferred example of aspect 14 (aspect 15), the second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path. In the fifteenth aspect, since the second flow path includes a diameter-expanded portion having a first tapered portion that extends in a tapered shape toward the downstream side of the first flow path toward the first flow path, the upstream side of the first flow path. Since the liquid flowing from the first to the downstream side can easily flow from the first flow path to the second flow path, the stagnation of the liquid that tends to occur in this portion can be suppressed. This makes it easier to exhaust the air bubbles that stay in the stagnation portion of the liquid, so that the air bubble discharge property can be improved.

[Aspect 16]
In a preferred example of aspect 15 (aspect 16), the enlarged diameter portion of the second flow path further has a second tapered portion that tapers toward the upstream side of the first flow path toward the first flow path. The inclination angle of the first tapered portion with respect to the second flow path is larger than the inclination angle of the second tapered portion with respect to the second flow path. In the 16th aspect, since the diameter-expanded portion of the second flow path has a second tapered portion that extends further to the upstream side in addition to the first tapered portion that extends to the downstream side of the first flow path, the diameter of the second flow path is expanded. Since the cross-sectional area of the portion can be increased, the liquid can be more easily flowed from the first flow path to the second flow path. Further, in the 16th aspect, since the inclination angle of the first tapered portion extending to the downstream side with respect to the second flow path is larger than the inclination angle of the second tapered portion extending to the upstream side with respect to the second flow path, the first taper Compared with the case where both the portion and the second tapered portion have the same inclination angle, the cross-sectional area of the second flow path can be prevented from becoming too large, so that a decrease in the flow velocity can be suppressed. In this way, the liquid can be made easier to flow from the first flow path to the second flow path while suppressing the decrease in the flow velocity, so that the discharge property of the bubbles can be further improved.

[Aspect 17]
In a preferred example (Aspect 17) of Aspect 15 or Aspect 16, the end of the enlarged diameter portion of the second flow path is open to the surface of the light transmitting member facing the light absorbing member. In aspect 17, since the end of the enlarged diameter portion of the second flow path is open on the surface of the light transmitting member facing the light absorbing member, it is easy to form the enlarged diameter portion in the second flow path. ..

[Aspect 18]
In any of the preferred examples (aspects 18) of aspects 15 to 17, a plurality of second flow paths are formed from the inlet flow path communicating with the first flow path to the downstream side, and the plurality of second flow paths are the first. The light absorbing member includes a flow path arranged at the downstream end of the 1 flow path and a flow path arranged between the downstream end of the first flow path and the inlet flow path. A protrusion that projects toward the enlarged diameter portion of the flow path at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path among the plurality of second flow paths. The part is formed. In the eighteenth aspect, the diameter of the second flow path is directed toward the enlarged diameter portion of the second flow path at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path. Since the protruding portion is formed, a flow is generated along the protruding portion of the first flow path and the enlarged diameter portion of the second flow path at the branch point between the first flow path and each of the second flow paths. Therefore, a flow from the first flow path to the second flow path is more likely to be formed. As a result, the stagnation of the liquid at each branch point is suppressed and the bubbles are easily discharged, so that the discharge property of the bubbles at each branch point can be further improved.

[Aspect 19]
In any preferred example of aspects 15 to 18 (Aspect 19), the first flow path is formed from one end to the other, and the inlet flow path is one end and the other. Arranged between the ends, the second flow path is located at both one end and the other end. In aspect 19, the first flow path is formed from one end to the other end, and the inlet flow path is located between one end and the other end, the second flow. Since the roads are arranged at both one end and the other end, the liquid flowing in from the inlet flow path branches and not only the second flow path at one end but also the other end. It becomes easy to flow to the second flow path of. According to this, stagnation of one end and the other end of the first flow path can be suppressed as compared with the case where there is no inlet flow path between one end and the other end. Therefore, it becomes easy to discharge the air bubbles that stay in the stagnation. As a result, uneven welding of laser welding can be reduced while suppressing stagnation of one end and the other end of the first flow path.

[Aspect 20]
In any of the preferred examples (aspect 20) of aspects 14 to 19, the first flow is formed in a flow path tube that projects to the opposite side of the flow path tube in which the second flow path is formed with respect to the welding surface. The number of flow path pipes having a third flow path communicating with the road and forming the third flow path is smaller than the number of flow path pipes forming the second flow path, and the cross-sectional area of the third flow path is It is larger than the cross-sectional area of the second flow path. In aspect 20, since the cross-sectional area of the third flow path is larger than the cross-sectional area of the second flow path, the pressure loss in the flow path can be reduced. In particular, when there are a plurality of second flow paths communicating with the first flow path, pressure loss is likely to occur, so that the effect of reducing this is great. Moreover, the third flow path is formed on the flow path tube that projects on the side opposite to the flow path tube on which the second flow path is formed with respect to the welding surface, that is, on the side opposite to the side that irradiates the laser beam. Therefore, even if the cross-sectional area of the third flow path is increased, the welding unevenness of laser welding can be reduced. As a result, uneven welding of laser welding can be reduced while reducing pressure loss.

[Aspect 21]
In a preferred example of aspect 20 (aspect 21), the outer circumference of the flow path pipe forming the third flow path has a size exceeding the region of the first flow path in a plan view from a direction orthogonal to the welding surface. In the 21st aspect, since the outer circumference of the flow path pipe forming the third flow path has a size exceeding the region of the first flow path in a plan view from a direction orthogonal to the welding surface, the cross-sectional area of the third flow path Can be made larger. Therefore, the effect of reducing the pressure loss in the first flow path can be enhanced.

[Aspect 22]
In a preferred example (Aspect 22) of Aspect 20 or Aspect 21, the light absorbing member comprises two light transmitting members joined to the light absorbing member and transparent to laser light, and the light absorbing member has two light transmitting members. It is sandwiched between the sex members and laminated, and the flow path tube of the second flow path is formed in one or both of the two light transmitting members. In aspect 22, since the two light-transmitting members that are joined to the light-absorbing member and have transparency to the laser light are provided, the laser light is irradiated from both surfaces of the two light-transmitting members, and 2 Each of the light transmitting members can be welded to the light absorbing member. At this time, since the flow path tube of the second flow path included in the region of the first flow path is formed on one or both of the two light transmissive members, the surface of any of the light transmissive members. Welding unevenness can be reduced even by irradiating with laser light.

[Aspect 23]
In a preferred example of Aspect 22 (Aspect 23), a flow path tube of the second flow path is formed in one of the two light transmitting members, and a flow path tube of the third flow path is formed in the other. In the 23rd aspect, since the flow path tube of the second flow path is formed in one of the two light transmitting members and the third flow path tube is formed in the other, the cross-sectional area of the third flow path is increased. Since it can be increased, the pressure loss in the first flow path can be reduced. Further, by performing laser welding to join the second substrate and the first substrate on which the flow path tube of the second flow path included in the region of the first flow path is formed, welding unevenness can be reduced. ..

[Aspect 24]
In a preferred example of Aspect 22 or Aspect 23 (Aspect 24), the light absorbing member is provided with a filter interposed between the two light transmitting members. In the 24th aspect, since the filter interposed between the two light transmitting members is provided in the light absorbing member, the laser light can be measured as compared with the case where the filter is provided in any of the two light transmitting members. Since it is not necessary to arrange the filters so that they do not overlap in the irradiation direction, it is possible to increase the degree of freedom in designing the arrangement and size of the filters.

[Aspect 25]
In any of the preferred examples (Aspect 25) of Aspects 14 to 24, the angle of the laser beam irradiation direction with respect to the welding surface is constant. In the 25th aspect, since the angle of the laser beam irradiation direction with respect to the welding surface is constant, laser welding can be easily performed as compared with the case where the laser beam irradiation angle is changed.

It is a block diagram of the printing apparatus to which the liquid injection apparatus which concerns on 1st Embodiment of this invention is applied. It is an exploded perspective view of the liquid injection head of 1st Embodiment. It is an exploded perspective view when the liquid injection head of 1st Embodiment is seen from another angle. FIG. 5 is a plan view of the liquid injection head of the first embodiment as viewed from the print medium side. It is an exploded perspective view of the liquid injection unit shown in FIG. It is sectional drawing of the injection head part shown in FIG. It is a side view and a plan view of the flow path structure shown in FIG. It is sectional drawing which shows the flow path structure in 1st comparative example. It is a figure which shows the flow path structure in 1st Embodiment, and is the cross-sectional perspective view which cut the flow path structure shown in FIG. 7 by IV-IV line. It is a partial cross-sectional view of the flow path structure cut by the VV line shown in FIG. 7. FIG. 10 is a side view and a plan view of a portion of the flow path structure shown in FIG. It is a process drawing which shows the manufacturing method of the flow path structure in 1st Embodiment. It is a partial cross-sectional view of the flow path structure which concerns on the modification of 1st Embodiment. It is a partial cross-sectional view of the flow path structure which concerns on other modification of 1st Embodiment. It is a partial cross-sectional view which shows the structure of the flow path structure in 2nd Embodiment of this invention. FIG. 15 is a side view and a plan view of a substrate constituting a portion of the flow path structure shown in FIG. It is sectional drawing which cut the part of the flow path structure shown in FIG. 15 by VII-VII line. It is an operation explanatory view of the part of the flow path structure in the 2nd comparative example. It is an operation explanatory view of the part of the flow path structure in 2nd Embodiment. It is a partial cross-sectional view of the flow path structure which concerns on the modification of 2nd Embodiment. It is a partial cross-sectional view of the flow path structure which concerns on other modification of 2nd Embodiment. It is a partial cross-sectional view of the flow path structure which concerns on other modification of 2nd Embodiment. It is sectional drawing which shows the relationship between the cross-sectional shape of the flow path shown in FIG. 22 and the height of a protrusion.

<Liquid injection device>
First, the liquid injection device according to the embodiment of the present invention will be described by taking an inkjet printing device as an example. FIG. 1 is a partial configuration diagram of a printing apparatus 100 according to an embodiment of the present invention. The printing device 100 is a liquid injection device that injects ink, which is an example of a liquid, onto a printing medium (injection target) M such as printing paper, and includes a control device 10, a transport mechanism 12, a liquid injection head 14, and a pump 16. To do. A liquid container (ink cartridge) 18 for storing inks I of a plurality of colors is attached to the printing apparatus 100. In the first embodiment, the four color inks I of cyan (C), magenta (M), yellow (Y), and black (B) are stored in the liquid container 18.

The control device 10 comprehensively controls each element of the printing device 100. The transport mechanism 12 transports the print medium M in the Y direction under the control of the control device 10. However, the structure of the transport mechanism 12 is not limited to the above examples. The pump 16 is an air supply device that supplies two systems of air A (A1, A2) to the liquid injection head 14 under the control of the control device 10. The air A1 and the air A2 are gases used for controlling the flow path inside the liquid injection head 14. The pump 16 can pressurize each of the air A1 and the air A2 independently of each other. The liquid injection head 14 injects the ink I supplied from the liquid container 18 onto the print medium M under the control of the control device 10. The liquid injection head 14 of the first embodiment is a long line head in the X direction that intersects the Y direction. The direction perpendicular to the XY plane (the plane parallel to the surface of the print medium M) is hereinafter referred to as the Z direction. The injection direction of ink I by the liquid injection head 14 corresponds to the Z direction.

<Liquid injection head>
2 and 3 are exploded perspective views for explaining the configuration of the liquid injection head 14 shown in FIG. As shown in FIGS. 2 and 3, the liquid injection head 14 includes a flow path structure G1, a flow path control unit G2, and a liquid injection unit G3. The flow path structure G1, the flow path control unit G2, and the liquid injection unit G3 are laminated in this order in the Z direction. The liquid injection unit G3 is a structure in which six liquid injection units U3 are housed and supported in the housing 142.

FIG. 4 is a plan view of the surface of the liquid injection unit G3 facing the print medium M. As illustrated in FIG. 4, the six liquid injection units U3 are arranged along the X direction. Each liquid injection unit U3 includes a plurality of injection head portions 70 (six in the example of the first embodiment) arranged along the X direction. Each injection head unit 70 includes a head chip that injects ink I from a plurality of nozzles N. The plurality of nozzles N of one injection head unit 70 are arranged in two rows along the W direction which is inclined at a predetermined angle with respect to the X direction and the Y direction. Ink I of four systems (four colors) is supplied in parallel to each injection head portion 70 of the liquid injection unit U3. The plurality of nozzles N of one injection head unit 70 are divided into four sets, and different inks I are ejected for each set.

Ink I of four systems is supplied from the liquid container 18 to the flow path structure G1, and air A (A1, A2) of two systems is supplied from the pump 16. The flow path structure G1 distributes each of the four systems of ink I and each of the two systems of air A into six systems corresponding to different liquid injection units U3. That is, the number of distributed inks (6) of one system of ink I by the flow path structure G1 exceeds the number of types K (K = 4) of ink I.

The flow path control unit G2 is an element that controls the flow path (for example, opening / closing of the flow path and the pressure in the flow path) of the liquid injection head 14, and is a six flow path control unit corresponding to different liquid injection units U3. It is configured to include U2. The four systems of ink I and the two systems of air A are supplied in parallel to the six flow path control units U2 by distribution in the flow path structure G1. Each flow path control unit U2 controls the opening / closing and pressure of the flow paths of the four systems of ink I distributed by the flow path structure G1 to each liquid injection unit U3 according to the two systems of air A.

After distribution in the flow path structure G1, four systems of ink I via each flow path control unit U2 are supplied in parallel to the six liquid injection units U3. As shown in FIG. 5, which will be described later, each liquid injection unit U3 includes a liquid distribution unit 60. The liquid distribution unit 60 distributes each of the four systems of ink I supplied from the flow path control unit U2 in the previous stage to the six systems corresponding to the different injection head units 70. That is, the four systems of ink I after distribution by the liquid distribution unit 60 are supplied in parallel to each of the six injection head units 70. Each injection head unit 70 injects each of the four systems of ink I from different nozzles N.

As shown in FIG. 2, four supply ports SI3 are formed on the surface of each liquid injection unit U3 of the liquid injection unit G3 facing the flow path control unit G2. When the flow path control unit G2 and the liquid injection unit G3 (housing 142) are fixed to each other, an outlet flow path of the flow path control unit U2 is formed at each supply port SI3 of each liquid injection unit U3. Each flow path tube DI2 is inserted. Therefore, the ink I of each system is supplied in parallel to the four supply ports SI3 of each liquid injection unit U3 from the flow path pipe DI2 of the flow path control unit U2.

FIG. 5 is an exploded perspective view of any one liquid injection unit U3. As shown in FIG. 5, the liquid injection unit U3 has six injection head portions 70 fixed to a fixing plate 58 in a laminated body of a filter portion 52, a communication member 54, a basic wiring board 56, and a liquid distribution portion 60. It is composed by joining. The filter unit 52 is an element that removes air bubbles and foreign substances contained in each ink I supplied from the flow path control unit G2. As shown in FIG. 5, the filter unit 52 is formed with four supply ports SI3 to which each ink I is supplied via the flow path control unit G2, and corresponds to the ink I supplied from each supply port SI3. It includes four filters 526. The communication member 54 communicates the outlets of the four filter units 52 with the liquid distribution unit 60. The communication member 54 is a flat plate material made of an elastic material (for example, rubber), and four through holes 542 communicating with each outlet of the four filter portions 52 are formed. The liquid distribution unit 60 distributes each of the four systems of ink I supplied from each supply port 60A through the through holes 542 of the communication member 54 to the six systems corresponding to each injection head unit 70.

An individual wiring board 78 is joined to each of the injection head portions 70. The individual wiring board 78 is inserted into the insertion port (slit) 60C formed in the liquid distribution unit 60 and joined to the basic wiring board 56. Each individual wiring board 78 is a flexible wiring board (COF (Chip On Film)) for electrically connecting the basic wiring board 56 and each injection head portion 70. The fixing plate 58 is a flat plate-shaped member that supports each injection head portion 70, and is made of a highly rigid metal such as stainless steel. As shown in FIG. 5, the fixing plate 58 is formed with six openings 582 corresponding to different injection head portions 70. Each opening 582 is a substantially rectangular through hole that is long in the W direction in a plan view.

FIG. 6 is a cross-sectional view (cross section perpendicular to the W direction) of one injection head portion 70. As shown in FIG. 6, the injection head portion 70 has a pressure chamber forming substrate 72 and a diaphragm 73 laminated on one surface of the flow path forming substrate 71, and a nozzle plate 74 and a compliance substrate 75 on the other surface. Includes the head chip on which. The plurality of nozzles N are formed on the nozzle plate 74. As shown in FIG. 6, since the structure corresponding to each row of the nozzles N is formed substantially line-symmetrically in one injection head portion 70, the following is convenient for one row of the nozzles N. The structure of the injection head portion 70 will be described with reference to it.

The flow path forming substrate 71 is a flat plate material that constitutes the flow path of the ink I. An opening 712, a supply flow path 714, and a communication flow path 716 are formed in the flow path forming substrate 71. The supply flow path 714 and the communication flow path 716 are formed for each nozzle N, and the opening 712 is continuous over a plurality of nozzles N for ejecting one system of ink I. The pressure chamber forming substrate 72 is a flat plate material in which a plurality of openings 722 corresponding to different nozzles N are formed. The flow path forming substrate 71 and the pressure chamber forming substrate 72 are formed of, for example, a silicon single crystal substrate.

The compliance substrate 75 is a mechanism for suppressing (absorbing) pressure fluctuations in the flow path of the injection head portion 70, and includes a sealing plate 752 and a support 754. The sealing plate 752 is a flexible film-like member, and the support 754 flows the sealing plate 752 so that the opening 712 of the flow path forming substrate 71 and each supply flow path 714 are closed. It is fixed to the road forming substrate 71.

The diaphragm 73 is installed on the surface of the pressure chamber forming substrate 72 opposite to the flow path forming substrate 71. The diaphragm 73 is a flat plate-like member that can vibrate elastically, and is composed of a laminate of an elastic film formed of an elastic material such as silicon oxide and an insulating film formed of an insulating material such as zirconium oxide. Will be done. As shown in FIG. 6, the diaphragm 73 and the flow path forming substrate 71 face each other with a gap inside each opening 722 formed in the pressure chamber forming substrate 72. The space sandwiched between the flow path forming substrate 71 and the diaphragm 73 inside each opening 722 functions as a pressure chamber (cavity) C that applies pressure to the ink. The pressure chambers C communicating with each nozzle N are arranged along the W direction.

A piezoelectric element 732 as a driving element corresponding to each nozzle N is formed on the surface of the diaphragm 73 on the side opposite to the pressure chamber forming substrate 72. Each piezoelectric element 732 is a laminated body in which a piezoelectric body is interposed between electrodes facing each other. The piezoelectric element 732 vibrates together with the diaphragm 73 due to the supply of the drive signal, so that the pressure in the pressure chamber C fluctuates and the ink I in the pressure chamber C is ejected from the nozzle N. Each piezoelectric element 732 is sealed and protected by a protective plate 76 fixed to the diaphragm 73.

The support 77 is fixed to the flow path forming substrate 71 and the protective plate 76. The support 77 is integrally formed, for example, by molding a resin material. The support 77 is formed with a recess 772 forming a liquid storage chamber (reservoir) R together with an opening 712 of the flow path forming substrate 71. The opening of the recess 772 is closed by the peripheral edge of the opening 712 of the flow path forming substrate 71 in a state of communicating with the opening 712 of the flow path forming substrate 71. The recess 772 is formed with an opening 774 that opens on the side surface of the support 77, and the opening 774 is closed by a lid 775.

The liquid storage chamber R is formed by the space including the recess 772 of the support 77, the opening 774, and the opening 322 of the flow path forming plate 32. By forming the opening 774 in the opening 774 in this way, the volume of the liquid storage chamber R can be increased as compared with the case where the opening 774 is not formed. The opening 774 of the support 77 may not be formed. The sealing plate 752 of the compliance substrate 75 described above constitutes the wall surface (bottom surface) of the liquid storage chamber R and absorbs the pressure fluctuation of the ink in the liquid storage chamber R.

As shown in FIG. 5, each injection head unit 70 is formed with a supply port 771 for supplying ink I of each system from the outlet of the liquid distribution unit 60, and the supply port 771 is provided in the liquid storage chamber R. Communicating. As a result, the ink I of each system after distribution by the liquid distribution unit 60 is supplied to and stored in the liquid storage chamber R from the outlet of the liquid distribution unit 60 through the supply port 771 of the injection head unit 70. The ink I stored in the liquid storage chamber R is distributed and filled in each pressure chamber C by a plurality of supply flow paths 714, passes through the communication flow path 716 and the nozzle N from each pressure chamber C, and is external (printing medium). It is injected to the M side).

The end portion of the individual wiring board 78 is joined to the diaphragm 73 shown in FIG. The individual wiring board 78 is a flexible substrate (flexible wiring board) on which wiring for transmitting a drive signal and a power supply voltage to each piezoelectric element 732 is formed. The individual wiring board 78 protrudes through the slit 762 formed in the protective plate 76 and the slit 776 formed in the support 77, and is connected to the basic wiring board 56 as described above. The drive signal and the power supply voltage are supplied from the basic wiring board 56 to the piezoelectric element 732 of each injection head portion 70 via the individual wiring boards 78.

<Structure of flow path structure in the first embodiment>
Here, the configuration of the flow path structure G1 in which the flow path of the fluid (liquid or gas) in the first embodiment is formed will be described more specifically. FIG. 7 is a side view and a plan view of the flow path structure G1. As shown in FIG. 7, the flow path structure G1 is a flat plate-like structure in which the first substrate 27 and the second substrate 28 are joined in a state of facing each other. The first substrate 27 and the second substrate 28 are flat plates long in the X direction, and are made of a resin material such as polypropylene. The first substrate 27 and the second substrate 28 are joined by laser welding as described later.

The first substrate 27 includes a first surface 271 on the opposite side of the second substrate 28 and a first facing surface 272 facing the second substrate 28 and opposite to the first surface 271. Similarly, the second substrate 28 includes a second surface 281 on the opposite side of the first substrate 27 and a second facing surface 282 facing the first substrate 27 and opposite to the second surface 281.

In FIG. 7, a plan view of the first surface 271 and a plan view of the second surface 281 are shown together. On the first surface 271 of the first substrate 27, four flow path tubes SI1 serving as inlet channels for supplying inks I (C, M, Y, K) of each system from the liquid container 18 and a pump 16 Two systems of gas, here two flow path tubes SA1 serving as an inlet flow path to which air A (A1, A2) is supplied, are formed. The flow path pipes SI1 and SA1 serving as the inlet flow paths project from the first surface 271 of the first substrate 27 to the negative side in the Y direction.

On the second surface 281 of the second substrate 28, there are six flow path tubes DI1 which are outlet flow paths corresponding to ink I of each system, and two outlet flow paths corresponding to air A of each system. A flow path tube DA1 is formed individually for each of the six liquid injection units U3. The six flow path tubes DI1 corresponding to any one system of ink I are arranged in the X direction at substantially equal intervals, and the six flow path tubes DA1 corresponding to any one system of air A are approximately equal to each other. They are arranged in the X direction at intervals. The flow path pipes DI1 and DA1 serving as these outlet flow paths project from the second surface 281 of the second substrate 28 to the positive side in the Y direction.

As shown by wavy lines in FIG. 7, between the first facing surface 272 of the first substrate 27 and the second facing surface 282 of the second substrate 28, four liquids corresponding to ink I of each system are used. The flow path PI1 and the two gas flow paths PA1 corresponding to the air A of each system are formed. Each flow path PI1 and each flow path PA1 extend substantially linearly along the X direction over substantially the entire range in which the six flow path control units U2 are arranged in a plan view. The four flow paths PI1 corresponding to the ink I are located on both sides of the two flow paths PA1 corresponding to the air A in a plan view. Each flow path PA1 corresponding to the air A is bent in a plan view so as to bypass the mounting hole 23.

Each flow path PI1 is formed so as to overlap one flow path tube SI1 for supplying ink I in a plan view, and is an inlet flow path formed in the flow path tube SI1 so as to penetrate the first substrate 27. Communicate with H1. Similarly, each flow path PA1 is formed so as to overlap one flow path tube SA1 for supplying air A in a plan view, and is formed in the flow path tube SA1 so as to penetrate the first substrate 27. Communicates with the inlet flow path H1.

In this way, each flow path PI1 communicates the inlet flow path H1 formed in one flow path pipe SI1 and the outlet flow path H2 formed in each of the six flow path pipes DI1. The road. Each flow path PA1 is a flow path that communicates the inlet flow path H1 formed in one flow path tube SA1 and the outlet flow path H2 formed in each of the six flow path tubes DA1. These flow paths PI1 and PA1 are formed by laminating the first substrate 27 and the second substrate 28 so that the first facing surface 272 and the second facing surface 282 are in contact with each other and forming one or both of them. It is constructed by fixing the periphery of the flow path groove. That is, the flow paths PI1 and PA1 here are regions surrounded by the fixing surface. The fixing surface surrounding the flow paths PI1 and PA1 may be, for example, a welding surface by laser welding or an adhesive surface, but here, the case where the fixing surface is composed of a welding surface by laser welding is used. Let's take an example.

When the flow paths PI1 and PA1 are formed by laser welding the first substrate 27 and the second substrate 28, one of the first substrate 27 and the second substrate 28 is made transparent to the laser light. It is composed of a light-transmitting member having a light-transmitting member, and the other is composed of a light-absorbing member having an absorption property for laser light. Then, laser light is irradiated from the surface of the substrate made of the light transmissive member to weld. In the first embodiment, the first substrate 27 is composed of a light absorbing member, the second substrate 28 is composed of a light transmitting member, and laser light is irradiated from the second surface 281 of the second substrate 28 for welding. Take the case of doing this as an example.

By the way, in the flow path structure G1 of the first embodiment, six flow path tubes DI1 are formed so as to project from the second surface 281 on the second surface 281 of the second substrate 28 that irradiates the laser light. There is. Therefore, the portion of the pipe surface of the flow path pipe DI1 is thicker than the other parts by the length (thickness) of the flow path pipe DI1 protruding from the second surface 281. In such a configuration, if the welding surface overlaps the tube surface of the flow path tube DI1 in the irradiation direction of the laser beam, the portion overlapping the tube surface of the flow path tube DI1 is compared with other parts. Since the laser beam is easily attenuated, there is a problem that uneven welding is likely to occur due to insufficient welding. If such welding unevenness occurs, the airtightness of the flow path may decrease.

Therefore, in the present embodiment, as shown in FIG. 7, the pipe surfaces (outer circumference) of the flow path pipes DI1 and DA1 are included in the region of each flow path PI1 and PA1 in a plan view. According to this, it is possible to prevent the welding surface surrounding each flow path PI1 and PA1 from overlapping the pipe surface of the flow path tubes DI1 and DA1 in the irradiation direction of the laser beam, so that welding unevenness can be effectively reduced. it can.

Here, the flow path structure of the flow path structure G1 of the first embodiment will be described in more detail while comparing with the first comparative example. FIG. 8 is a cross-sectional perspective view showing the flow path structure of the first comparative example, in which the welding surface W'surrounding the first flow path P'in the irradiation direction of the laser beam L'is the flow of the second flow path Q'. This is a case where it overlaps the pipe surface of the road pipe D'. FIG. 9 is a diagram showing a flow path structure according to the first embodiment, and is a cross-sectional perspective view of the flow path structure G shown in FIG. 7 cut along an IV-IV line. In FIG. 9, the welding surface W surrounding the first flow path P in the irradiation direction of the laser beam L corresponds to the flow path tubes DI1 and DA1 of the outlet flow path H2, and the tube surface of the flow path tube D of the second flow path Q. It is a case where it does not overlap with. 8 and 9 are views in the case of cutting on a plane including the welding surfaces W and W'after laser welding. The "first flow path" in the first embodiment is a flow path in which a fluid (liquid or gas) flows while being surrounded by a welding surface by laser welding. In this respect, the flow path PI1 of each liquid and the flow path PA1 of each gas correspond to the "first flow path" in the first embodiment, and the outlet flow path H2 corresponds to the "second flow path". On the other hand, in the second embodiment described later, a flow path configuration for improving the exhaust property of air bubbles contained in the liquid flowing through the flow path will be illustrated. Therefore, the flow path PI1 of each liquid corresponds to the "first flow path" in the second embodiment.

In FIG. 8, the flow path tube D'forming the second flow path Q'is formed so as to project from the second surface 281' of the second substrate 28'on the positive side in the Z direction, and is formed on the first substrate 27'. The first flow path P'surrounded by the welding surface W'is formed by welding the periphery of the flow path groove 273'formed in 1 with the laser beam L'. In FIG. 9, the flow path tube D forming the second flow path Q is formed so as to project from the second surface 281 of the second substrate 28 to the positive side in the Z direction, and the flow path formed on the first substrate 27. By welding the periphery of the groove 273 with the laser beam L, the first flow path P surrounded by the welding surface W is formed.

In the configuration of the first comparative example of FIG. 8, in the plan view from the irradiation direction of the laser beam L', that is, the direction orthogonal to the welding surface W'(negative side in the Z direction), the tube surface of the flow path tube D'is It is arranged beyond the region of the first flow path P'. In such a configuration of the first comparative example, the welding surface W'surrounding the first flow path P'overlaps the tube surface of the flow path tube D'of the second flow path Q'in the irradiation direction of the laser beam L'. It ends up. The portion of the pipe surface of the flow path pipe D'is thicker than the second surface 281' by the length (thickness) of the flow path pipe D protruding from the second surface 281'. Therefore, as shown in FIG. 8, if there is a welding surface W ″ that overlaps the tube surface of the flow path tube DI1 among the welding surfaces W ′ in the irradiation direction of the laser beam, the welding surface W ″ is irradiated. Since the laser beam La'is more likely to be attenuated than the laser beam L of other portions, uneven welding is likely to occur due to insufficient welding.

On the other hand, in the configuration of the first embodiment shown in FIG. 9, the tube of the flow path tube D is viewed in a plan view from the irradiation direction of the laser beam L, that is, the direction orthogonal to the welding surface W (negative side in the Z direction). The surface is arranged in the region of the first flow path P. Thereby, the welding surface W surrounding the first flow path P can be prevented from overlapping the tube surface of the flow path tube D of the second flow path Q in the irradiation direction of the laser beam L. Therefore, since the laser beam L is not attenuated due to the difference in thickness, welding can be sufficiently performed and uneven welding can be effectively reduced. As a result, the first flow path P having high airtightness can be formed.

The flow path structure of the first embodiment will be described more specifically by taking the liquid flow path PI1 as an example. The liquid flow path PI1 in the first embodiment has four systems, and the flow path structure of the portion of the flow path structure G1 including each is configured in the same manner. Therefore, here, any one system of flow path PI1 is used. The flow path structure of the including portion will be taken out and described. FIG. 10 is a partial cross-sectional view of the flow path structure G1 cut along the VV line shown in FIG. FIG. 11 is a side view and a plan view when the first substrate 27 and the second substrate 28 constituting the portion of the flow path structure G1 shown in FIG. 10 are disassembled.

As shown in FIGS. 10 and 11, the first facing surface 272 of the first substrate 27 communicates with the flow path groove 273 extending in the X direction along the first facing surface 272 and the flow path groove 273. The inlet flow path H1 is formed. The flow path groove 273 is a groove having a substantially rectangular cross section that constitutes the flow path PI1 corresponding to the first flow path, and the inlet flow path H1 is formed on the flow path tube SI1 protruding from the first surface 271 of the first substrate 27. It is a through hole to be formed. The flow path groove 273 is formed over two ends 273a and 273b of the flow path PI1 which are separated in the X direction, and the inlet flow path H1 is arranged between these ends 273a and 273b.

Six outlet flow paths H2 corresponding to the second flow path are formed on the second facing surface 282 of the second substrate 28 in the direction perpendicular to the second facing surface 282 (Z direction). The outlet flow path H2 is a through hole formed in the flow path tube DI1 protruding from the second surface 281 of the second substrate 28. The six outlet flow paths H2 are arranged on both sides of the inlet flow path H1 in a plan view from the Z direction. The inlet flow path H1 is located closer to one end 273a than the center of one end 273a and the other end 273b. Therefore, the number of outlet flow paths H2 arranged between the inlet flow path H1 and the end portions 273a and 273b is different.

Specifically, one outlet flow path H2 is arranged at each of both ends 273a and 273b of the flow path groove 273. One outlet flow path H2 is arranged in the middle of the inlet flow path H1 and one end 273a (on the right side of the inlet flow path H1 in FIGS. 10 and 11), and the inlet flow path H1 and the other end flow path H2 are arranged. Three outlet flow paths H2 are arranged in the middle of the end portion 273b (on the left side of the inlet flow path H1 in FIGS. 10 and 11).

According to such a flow path structure, the ink flowing in from the inlet flow path H1 branches to the negative side and the positive side in the X direction and flows toward both ends 273a and 273b of the flow path PI1. That is, in the flow path PI1, the ink flow from the upstream side inlet flow path H1 toward the downstream one end 273a and the opposite direction from the upstream side inlet flow path H1 to the downstream side. A flow of ink occurs towards the other end 273a.

The ink flowing toward one end 273a of the flow path PI1 branches into the outlet flow path H2 of the end 273a and one outlet flow path H2 between the end 273a and the inlet flow path H1 and flows out. Will be done. The ink flowing toward the other end 273b of the flow path PI1 branches into the outlet flow path H2 at the end 273b and the three outlet flow paths H2 between the end 273b and the inlet flow path H1 and flows out. Will be done. The number and arrangement of the inlet flow path H1 and the outlet flow path H2 are not limited to those described above.

The first substrate 27 and the second substrate 28 configured in this way are laminated so that the first facing surface 272 and the second facing surface 282 are in contact with each other, and are directed toward the second surface 281 of the second substrate 28. The periphery of the flow path groove 273 is welded by the laser beam irradiated. As a result, the flow path (first flow path) PI1 is formed by the space formed by the inner wall surface of the flow path groove 273 of the first substrate 27 and the wall surface facing the flow path groove 273 of the second substrate 28. To.

The welded surface W thus formed has, for example, an annular shape as shown by hatching in the plan view of the first substrate 27 and the second substrate 28 in FIG. The flow path PI1 is a region surrounded by the welding surface W (the region inside the inner peripheral edge of the annular welding surface W). As shown in the plan view of the second substrate 28 of FIG. 11, all six flow path tubes DI1 including the tube surface are arranged so as to be included in the region of the flow path PI1. As a result, the welding surface W surrounding the flow path PI1 can be prevented from overlapping the pipe surface of the flow path pipe DI1 in the irradiation direction of the laser beam. Therefore, as described above, the laser beam L is not attenuated due to the difference in thickness, so that welding unevenness can be effectively reduced. In addition, although the case where the flow path pipe DI1 of FIGS. 10 and 11 protrudes in the direction orthogonal to the welding surface W is taken as an example, the flow path pipe DI1 protrudes in the direction inclined to the welding surface W. May be good.

Regarding the "flow path surrounded by the welding surface" here, when there is an error in the flatness of each of the first substrate 27 composed of the light absorbing member and the second substrate 28 composed of the light transmitting member. In consideration of the above, even if the entire molten surface of the light absorbing member is not in contact with the light transmitting member, both are fixed as surfaces, and as a result, the flow path PI1 may be formed. Therefore, when the gap between the two is sealed, the distance between the facing surface of the light absorbing member and the facing surface of the light transmitting member is 0.3 mm or less, and the light absorbing member in that portion is Even if it is melted, it is included in the "welded surface".

Further, whether or not the gap between the light absorbing member and the light transmitting member is sealed (airtightness) is measured by, for example, the following method. All other flow paths communicating with the flow path to be measured are closed, + 50 kPa of air is sent, and the pressure change of the flow path to be measured is measured. At this time, if the pressure change 5 seconds after the air is sent is within 1 kPa, it is assumed that the flow path to be measured is sealed.

Further, according to the flow path structure shown in FIG. 10, since the inlet flow path H1 of the flow path PI1 is between the outlet flow paths (second flow paths) H2 of both ends 273a and 273b of the flow path PI1, it is an inlet. The ink flowing in from the flow path H1 branches and easily flows not only to the outlet flow path H2 at one end 273a but also to the outlet flow path H2 at the other end 273b. According to this, as compared with the case where the inlet flow path H1 is not provided between both end portions 273a and 273b, the ink stagnation at both end portions 273a and 273b of the flow path PI1 can be suppressed, so that the ink stagnation can be suppressed. It becomes easier to discharge the stagnant air bubbles. As a result, uneven welding of laser welding can be reduced while suppressing stagnation at both ends 273a and 273b of the flow path PI1.

<Manufacturing method of flow path structure>
Next, a method of manufacturing the flow path structure G1 will be described. FIG. 12 is a process diagram showing a method for manufacturing the flow path structure G1. Here, a method of manufacturing the flow path structure G1 will be described with reference to a partial cross-sectional view of the flow path structure G1 cut along the VV line shown in FIG. 7. First, in step a of FIG. 12, the first substrate 27 is manufactured from a thermoplastic resin that absorbs laser light. Examples of the thermoplastic resin having such light absorption include those in which a predetermined coloring material such as carbon black, a dye or a pigment is mixed with polyamide (PA) or the like.

A flow path pipe SI1 protruding from the first surface 271 is formed on the first surface 271 of the first substrate 27, and a through hole forming an inlet flow path (third flow path) H1 is formed in the flow path pipe SI1. To do. A flow path groove 273 constituting the flow path (first flow path) PI1 is formed on the first facing surface 272 of the first substrate 27. At this time, the flow path tubes SI1 and SA1 and the inlet flow path H1 of other systems are also formed on the first surface 271 of the first substrate 27, and the other system is formed on the first facing surface 272 of the first substrate 27. The flow path groove 273 constituting the flow paths PI1 and PA1 of the above is also formed. The first substrate 27 may be manufactured by integral molding, or may be manufactured by processing a flat plate material.

Subsequently, in step b of FIG. 12, the second substrate 28 is manufactured from a thermoplastic resin that transmits laser light. Examples of the thermoplastic resin having such light transmittance include polyamide (PA), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), styrene-acrylonitrile copolymer, and ABS resin. , Acrylic resin (PMMA), polypropylene (PC), polybutylene terephthalate (PBT) and the like. If necessary, reinforcing fibers such as glass fiber and carbon fiber and those to which a coloring material is added may be used. Six flow path pipes DI1 protruding from the second surface 281 are formed on the second surface 281 of the second substrate 28, pass through each flow path pipe DI1, and penetrate from the second surface 281 to the second facing surface 282. Outlet flow path (second flow path) H2 through hole is formed. At this time, the flow path pipes DI1 and DA1 of other systems and the outlet flow path H2 through hole are also formed on the second substrate 28. The second substrate 28 may be manufactured by integral molding, or may be manufactured by processing a flat plate material.

Next, in step c of FIG. 12, the first substrate 27 and the second substrate 28 are laminated so that the first facing surface 272 and the second facing surface 282 are in contact with each other, and in step d of FIG. , The laser beam L is irradiated from the second surface 281 side of the second substrate 28. Then, the laser light L passes through the second substrate 28 made of the light transmitting member and is absorbed by the first substrate 27 made of the light absorbing member. At this time, the dye or pigment contained in the light absorbing member generates heat to melt the resin, and the heat generated at that time is transferred to the light transmitting member. The transferred heat also melts the light transmissive member to form a welded surface W. The melting by the laser beam L may be performed only on the portion to be the welding surface W, or may be collectively performed on the portion to be the welding surface W and the portion to be the flow path. Good.

The type of laser light L is appropriately selected and used depending on the absorption spectrum of the material of the second substrate 28 that transmits the laser light, the plate thickness (transmission length), and the like. Specifically, for example, a glass: neodymium ³⁺ laser, YAG: Nd ³⁺ laser, a ruby laser, a helium - neon laser, krypton laser, argon laser, _{H 2} laser, _{N 2} laser, can be selected from a laser beam of a semiconductor laser or the like.

By welding around the flow path groove 273 with such laser light L, a flow path (first flow path) PI1 surrounded by the welding surface W is formed. At this time, the flow paths PI1 and the flow paths PA1 of other systems are also formed in the same manner. In this way, the flow path structure G1 having the flow path structures shown in FIGS. 10 and 11 is formed. As described above, in the flow path structure G1 of the first embodiment, the pipe surface (outer circumference) of the flow path pipe DI1 is included in the region of each flow path PI1, and the pipe surface (outer circumference) of each flow path pipe DA1 is included. It is configured to be included in the region of the flow path PA1. Therefore, when the laser beam L is irradiated, the welding surface W surrounding each flow path PI1 does not overlap the tube surface of the flow path tube DI1 in the irradiation direction, and the welding surface W surrounding each flow path PA1 is the flow path tube. Since it does not overlap the pipe surface of DA1, welding unevenness of each welding surface W can be effectively reduced. As a result, the airtightness of the flow path tube DI1 formed by being surrounded by the welding surface W can be improved.

The irradiation direction of the laser beam L may be oblique to the welding surface W, but by making it orthogonal to the welding surface W as in step d of FIG. 12, the effects of attenuation and refraction are affected. Without thinking, the laser beam L can be transmitted through the light transmitting member having the same thickness over the entire welding surface W. Further, the angle of the irradiation direction of the laser beam L with respect to the welding surface W is preferably constant over the entire welding surface W. According to this, laser welding is easier than when the irradiation angle of the laser beam L is changed. Further, the above-mentioned light absorbing member and light transmitting member are not limited to those that absorb (or transmit) 100% of the laser light L. The light-absorbing member and the light-transmitting member have different light absorption rates (or light transmittance) for at least one wavelength of the laser light L, and the light-transmitting member has a higher light-absorbing rate than the light-transmitting member. It should be easy to see through. Therefore, the light absorbing member and the light transmitting member may have a light absorption rate (or light transmittance) of less than 100%.

Further, in the flow path structure shown in FIG. 10, the flow path pipe SI1 of the inlet flow path H1 functions as the inlet flow path H1 of the flow path PI1, but the welding surface of the flow path PI1 as the first flow path. It can also be thought of as a flow path pipe of a third flow path that protrudes to the side opposite to the flow path pipe DI1 of the outlet flow path H2 as the second flow path with respect to W. Such a third flow path is formed so as to project from the welding surface W on the side opposite to the flow path tube on which the second flow path is formed, that is, on the side opposite to the side on which the laser beam is irradiated. Therefore, even if the cross-sectional area of the flow path pipe of the third flow path is increased so as to exceed the region of the first flow path formed by surrounding the welding surface W, the laser welding is not affected. Welding unevenness can be reduced.

Therefore, in the first embodiment, as shown in FIG. 11, the flow path as the first flow path formed by surrounding the outer circumference of the flow path pipe SI1 with the welding surface W in a plan view from the positive side in the Z direction. The cross-sectional area of the inlet flow path H1 of the flow path pipe SI1 is made larger than the cross-sectional area of the flow path pipe DI1 of the outlet flow path H2 by increasing the size so as to exceed the region of PI1. By enlarging the outer circumference of the flow path pipe SI1, the cross-sectional area of the inlet flow path H1 can be further increased. By increasing the cross-sectional area of the inlet flow path H1 in this way, the pressure loss in the flow path PI1 can be reduced. In particular, as shown in FIG. 10, when there are a plurality of outlet flow paths H2 communicating with the flow path PI1, pressure loss is likely to occur, so that the effect of reducing this is great. As a result, uneven welding of laser welding can be reduced while reducing pressure loss.

As the flow path pipe formed on the first surface 271 of the first substrate 27, another flow path pipe forming a third flow path communicating with the flow path PI1 may be further provided. The third flow path in this case may be the inlet flow path of the flow path PI1 or the outlet flow path of the flow path PI1. As described above, the third flow path can have a larger cross-sectional area than the second flow path. Therefore, when a plurality of such third flow paths are provided, the third flow path is relative to the number of second flow paths. If the number of is too large, it affects the flow of the second flow path. Therefore, the number of the third flow paths is preferably smaller than the number of the second flow paths.

Further, in the flow path structure shown in FIG. 10, the case where the flow path groove 273 of the flow path PI1 is formed on the first substrate 27 side is given as an example, but the present invention is not limited to this. For example, as shown in FIG. 13, the flow path groove 283a may be formed on the second facing surface 282 on the second substrate 28 side. The flow path structure shown in FIG. 13 is formed by laminating the first substrate 27 and the second substrate 28 and joining the periphery of the flow path groove 283a by laser welding. As a result, the flow path PI1 is formed by the space formed by the inner wall of the flow path groove 283a of the second substrate 28 and the wall surface of the first substrate 27 facing the flow path groove 283a. Also in this case, as shown in FIG. 13, the welding surface W surrounding the flow path PI1 is included in the region of the flow path PI1 in the plan view. Since it can be prevented from overlapping the pipe surface of DI1, welding unevenness due to laser welding can be effectively reduced.

Further, in the first embodiment, the cross-sectional shape when the flow path PI1 is viewed in cross section in a cross section orthogonal to the flow direction of the flow path PI1 is on the first surface 271 side of the first substrate 27, as shown in FIG. A curved surface is formed so that the flow path width becomes narrower as it approaches the first surface 271. The cross-sectional shape of the flow path PI1 is not limited to this, and may be rectangular, but if a curved surface as shown in FIG. 9 is formed, stagnation of the corners of the flow path PI1 is less likely to occur. Further, as shown in FIG. 13, the cross section of the flow path PI1 becomes narrower on the second surface 281 side of the second substrate 28 as it approaches the second surface 281. Such a curved surface may be formed.

Further, in the first embodiment, as shown in FIG. 10, a flow path structure G1 having a two-layer structure in which two substrates (first substrate 27 and second substrate 28) are joined is given as an example, but the present invention is limited to this. It may be a flow path structure G1 having a three-layer structure in which three substrates are joined. For example, the three-layered flow path structure G1 shown in FIG. 14 is joined to a first substrate 27 made of one light absorbing member, and is made of two light transmitting members having transparency to laser light. It includes two substrates 28a and 28b. The first substrate 27 is sandwiched and laminated between the two second substrates 28a and 28b.

The first substrate 27 includes a facing surface 272a facing the second substrate 28a and a surface opposite to the facing surface 272a and facing the second substrate 28b. The second substrate 28a includes a facing surface 282a facing the first substrate 27 and a second surface 281a opposite to the facing surface 282a. The second substrate 28b includes a facing surface 282b facing the first substrate 27 and a first surface 281b opposite to the facing surface 282b.

The flow path PI1 is divided into a first flow path chamber PI1a and a second flow path chamber PI1b by a filter F provided in the first substrate 27. The first flow path chamber PI1a is surrounded by an inner wall of the first flow path hole 273c formed on the facing surface 272a of the first substrate 27 and a wall surface of the second substrate 28a facing the first flow path hole 273c. It is a space. The second flow path chamber PI1b is composed of an inner wall of the second flow path hole 273d formed on the facing surface 272b of the first substrate 27 and an inner wall of the flow path groove 283b formed on the facing surface 282b of the second substrate 28b. It is an enclosed space.

The flow path tube SI1 of one inlet flow path H1 is formed so as to project from the first surface 281b of the second substrate 28b, and the flow path tube DI1 of the six outlet flow paths H2 is the second of the second substrate 28a. It is formed so as to project from the surface 281a. Each outlet flow path H2 communicates with the first flow path chamber PI1a of the flow path PI1. The inlet flow path H1 communicates with the second flow path chamber PI1b of the flow path PI1. According to such a flow path structure, the ink flowing in from the inlet flow path H1 flows from the first flow path chamber PI1a of the flow path PI1 to the second flow path chamber PI1b of the flow path PI1 via the filter F. It flows out from each outlet flow path H2. The filter F collects air bubbles and foreign matter from the ink supplied to the inlet flow path H1. Ink from which air bubbles and foreign substances have been removed by passing through the filter F flows out from each outlet flow path H2.

The first flow path chamber PI1a of the flow path PI1 is formed by being surrounded by a welding surface Wa by laser welding between the facing surface 282a of the second substrate 28a and the facing surface 272a of the first substrate 27. The second flow path chamber PI1b of the flow path PI1 is formed by being surrounded by a welding surface Wb by laser welding between the facing surface 282b of the second substrate 28b and the facing surface 272b of the first substrate 27.

In this way, the flow path structure G1 shown in FIG. 14 is laminated by sandwiching the first substrate 27 made of the light absorbing member between the two second substrates 28a and 28b made of the light transmitting member. , The flow path PI1 can be formed by laser welding from both sides of the second substrates 28a and 28b. Specifically, in a state where the first substrate 27 is sandwiched between the two second substrates 28a and 28b and laminated, laser light La is irradiated from the second surface 281a of the second substrate 28a to form the second substrate 28b. The laser beam Lb is also irradiated from the first surface 281b. As a result, the first flow path chamber PI1a of the flow path PI1 is formed by the welding surface Wa welded by the laser light La, and the second flow path chamber PI1b of the flow path PI1 is formed by the welding surface Wb welded by the laser light Lb. Will be done.

In the flow path structure G1 shown in FIG. 14, since the flow path PI1 is formed by laser welding from both sides of the second substrates 28a and 28b, not only the flow path tube DI1 forming the outlet flow path H2 but also the inlet flow Regarding the flow path pipe SI1 forming the path H1, all the end faces (outer circumferences) of the flow path pipe DI1 and the flow path pipe SI1 are included in the region of the flow path PI1 in the plan view from the Z direction. In this respect, in the configuration shown in FIG. 14, not only the flow path pipe DI1 but also the flow path pipe SI1 corresponds to the flow path pipe forming the second flow path. Therefore, it is possible to prevent the end faces of the flow path tubes DI1 and the flow path tubes SI1 from overlapping the welding surfaces Wa and Wb in both the irradiation directions of the laser beams La and Lb. As a result, uneven welding of the welded surfaces Wa and Wb can be reduced.

However, it is not limited to this. Of the second substrates 28a and 28b, one may be bonded to the first substrate 27 by laser welding, and the other and the first substrate 27 may be bonded by an adhesive or the like. According to this, one of the second substrates 28a and 28b that is not laser welded can be provided with a flow path tube in which a third flow path beyond the region of the flow path PI1 which is the first flow path is formed. .. For example, the flow path pipe SI1 shown in FIG. 14 is enlarged to exceed the area of the flow path PI1 in the same manner as the flow path pipe SI1 shown in FIG. It may be larger than the cross-sectional area of the flow path pipe DI1 of the outlet flow path H2. As a result, the pressure loss in the flow path PI1 can be reduced. Such a flow path pipe SI1 corresponds to a flow path pipe forming the third flow path. In this case, the second substrate 28a on which the flow path tube DI1 of the outlet flow path H2 is formed and the first substrate 27 are joined by laser welding, and the second substrate on which the flow path tube SI1 having a large cross-sectional area is formed is formed. By joining the 28b and the first substrate 27 with an adhesive or the like, it is possible to reduce welding unevenness due to laser welding.

Further, since the filter F interposed between the two second substrates 28a and 28b is provided on the first substrate 27 sandwiched between the second substrates 28a and 28b, the filter F can be used on the two second substrates 28a and 28b. Compared with the case where it is provided in any of 28b, it is not necessary to arrange the filter F so that it does not overlap in the irradiation direction of the laser beam, so that the degree of freedom in designing the arrangement and size of the filter F can be increased. ..

Further, an inclined surface is formed on the wall surface of the end portion 273a and 273b of the flow path PI1, and a diameter-expanded portion 284 having a tapered inclined surface extending to the downstream side is formed on the outlet flow path H2 of the end portion 273a and 273b. By doing so, the stagnation of the ink at the end portions 273a and 273b of the flow path PI1 can be suppressed, and the discharge property of the bubbles staying in the stagnation portion can be improved. As shown in FIG. 14, a plurality of inclined surfaces may be formed on the wall surface of the end portions 273a and 273b so that these inclined surfaces are joined to each other, or one inclined surface may be formed. Each of the inclined surfaces of the enlarged diameter portion 284 is configured to be joined by the inclined surface of the wall surface of the end portions 273a and 273b and the welding surface Wa. The shapes of the end portions 273a and 273b of the flow path PI1 and the diameter-expanded portion 284 will be described in detail with reference to the second embodiment.

<Flower path structure in the second embodiment>
Next, the flow path structure G1 in the second embodiment will be described. In the first embodiment, in laser welding to a substrate on which the flow path tube is projected, the airtightness of the first flow path formed by being surrounded by the welding surface can be improved by reducing the welding unevenness. The structure G1 has been described. In the second embodiment, in a flow path structure in which the first flow path through which the liquid flows is provided with the second flow path branching from the first flow path, the stagnation of ink at the branch point is suppressed to improve the bubble discharge property. The flow path structure G1 that can be improved will be described.

FIG. 15 is a cross-sectional view for explaining the configuration of the flow path structure G1 in the second embodiment. FIG. 15 corresponds to FIG. 10, and the configuration of the second embodiment is cut by the VV line of the flow path PI1 of the four ink I systems of the flow path structure G1 shown in FIG. It is a partial cross-sectional view of one system. 16 is a side view and a plan view of the first substrate 27 and the second substrate 28 forming the portion of the flow path structure G1 shown in FIG. 15 when they are disassembled, and corresponds to FIG. 11. FIG. 17 is a cross-sectional perspective view of the VI-VI line shown in FIG. 15, which corresponds to FIG.

The flow path structure G1 of the second embodiment is a further devised flow path structure of the four liquid flow paths PI1 of the first embodiment. Therefore, the portions of FIGS. 15 to 17 that have the same functions as the flow path structure G1 of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The flow path structure of the second embodiment shown in FIG. 15 is different from the flow path structure of the first embodiment shown in FIG. 10 in the flow paths 273a and 273b at both ends of the flow path (first flow path) PI1. At each branch point of PI1 and the outlet flow path (second flow path) H2, the inclined surface TP1 on the flow path PI1 side and the outlet flow path H2 side are inclined in the direction of the flow of the flow path PI1 as shown in FIG. This is the point where the tapered portion TD1 is formed.

Similar to the flow path PI1 shown in FIG. 10, the flow path PI1 shown in FIG. 15 is provided with one outlet flow path H2 at each of both ends 273a and 273b of the flow path PI1, and both ends 273a of the flow path PI1. Since four outlet flow paths H2 are arranged between 273b, there are four branch points between the flow path PI1 and the outlet flow path H2.

Since the inlet flow path H1 is arranged between both ends 273a and 273b of the flow path PI1 on the side opposite to the outlet flow path H2, the ink flow in the flow path PI1 is as follows. That is, the ink flowing toward one end 273a of the flow path PI1 branches into the outlet flow path H2 of the end 273a and one outlet flow path H2 between the end 273a and the inlet flow path H1. Is leaked. The ink flowing toward the other end 273b of the flow path PI1 branches into the outlet flow path H2 at the end 273b and the three outlet flow paths H2 between the end 273b and the inlet flow path H1 and flows out. Will be done. In the second embodiment, the inclined surface TP1 on the flow path PI1 side and the tapered portion on the outlet flow path H2 side described above are formed at the branch points of both ends 273a and 273b of the flow path PI1 and the four outlet flow paths H2. TD1 is formed.

Hereinafter, a configuration example of the inclined surface TP1 on the flow path PI1 side and the tapered portion TD1 on the outlet flow path H2 side will be described. First, the inclined surface TP1 on the flow path PI1 side will be described. As shown in FIGS. 15 and 16, at the branch point of the end portions 273a and 273b of the flow path PI1, an inclined surface TP1 is formed on the wall surface of each end portion 273a and 273b.

On the other hand, at the four branch points between both ends 273a and 273b of the flow path PI1, each of the protrusions protruding from the portion of the flow path PI1 facing the outlet flow path H2 toward the outlet flow path H2. 274 is formed, and an inclined surface TP1 is formed on the wall surface on the upstream side of the protrusion 274. The inclined surface TP1 is inclined so that the height of the protrusion 274 becomes higher toward the downstream side with respect to the flow direction in the flow path PI1. The details of the height of the protrusion 274 will be described later.

An inclined surface TP2 is also formed on the wall surface on the downstream side of each protrusion 274. The inclined surface TP2 is inclined to the side opposite to the inclined surface TP1 with respect to the flow direction in the first flow path. That is, the inclined surface TP2 is inclined so that the height of the protrusion 274 becomes lower toward the downstream side. In this way, by forming the inclined surface TP2 on the wall surface on the downstream side of the protrusion 274 as well, as compared with the case where the inclined surface TP2 is not formed on the downstream side, the flow path PI1 is downstream of the protrusion 274. The stagnation on the side can be suppressed.

Next, the tapered portion TD1 on the outlet flow path H2 side will be described. Each of the six outlet flow paths H2 is formed with a diameter-expanded portion 284 at a portion that opens to the second facing surface 282 of the second substrate 28, and the diameter-expanded portion 284 is directed toward the flow path PI1 (negative in the Z direction). A tapered portion TD1 is formed so as to spread in a tapered shape on the downstream side of the flow path PI1 (toward the side). The diameter-expanded portion 284 is a flow path between the outlet flow path H2 and the flow path PI1, and is a portion where the flow path diameter continuously increases from the outlet flow path H2 to the flow path PI1. As shown in FIGS. 16 and 17, the tapered portion TD1 is a portion of the inner peripheral surface of the enlarged diameter portion 284 on the downstream side of the flow path PI1, and is directed toward the second facing surface 282 with the first substrate 27. It is a shape in which the gradually expanding conical surface is halved. Since the enlarged diameter portion 284 of the outlet flow path H2 is open to the second facing surface 282 of the second substrate 28 with the first substrate 27, it is easy to form the enlarged diameter portion 284 in the outlet flow path H2.

In the second embodiment, as in the first embodiment, the inlet flow path H1 is arranged between both end portions 273a and 273b of the flow path PI1, so that the inlet flow path H1 and one end portion 273a The direction of the flow in the flow path PI1 is opposite between the space (right side in FIG. 15) and the space between the inlet flow path H1 and the other end portion 273b (left side in FIG. 15). Therefore, the arrangement positions of the inclined surface TP1 and the tapered portion TD1 are also reversed on the left and right sides of FIG.

The relationship between the inclined surface TP1 and the tapered portion TD1 is as follows. As shown in the enlarged view of FIG. 15, the inclined surface TP1 on the upstream side of the protrusion 274 is arranged on the upper surface of the flow path PI1 (bottom surface 273e of the flow path groove 273) facing the enlarged diameter portion 284 of the outlet flow path H2. Has been done. Further, when a virtual line y extending along the inclination of the inclined surface TP1 on the upstream side wall surface of the protrusion 274 is drawn in the cross-sectional view of FIG. 15, this virtual line y is formed by the tapered portion TD1 of the enlarged diameter portion 284. It passes through the region (including the boundary line between the tapered portion TD1 and the second facing surface 282). According to this, at each branch point, a part of the ink flow of the flow path PI1 can be guided to the tapered portion TD1 of the enlarged diameter portion 284 along the inclined surface TP2 on the wall surface on the upstream side of the protrusion 274. it can. As a result, the ink flow in the flow path PI1 can be facilitated toward the outlet flow path H2, so that the effect of improving the exhaust property of air bubbles can be enhanced.

The inclined surface TP1 of the end portions 273a and 273b of the flow path PI1 has the same shape as the tapered portion TD1 and is formed upside down from the tapered portion TD1. That is, the inclined surface TP1 has a shape obtained by halving the conical surface that gradually expands toward the first facing surface 272 with the second substrate 28. The first facing surface 272 and the first facing surface 272 and the first facing surface 272 so that the arc-shaped boundary line between the inclined surface TP1 and the first facing surface 272 and the arc-shaped boundary line between the tapered portion TD1 and the second facing surface 282 coincide with each other. 2 Facing surfaces 282 are joined. As a result, at the ends 273a and 273b of the flow path PI1, the inclined surface TP1 and the tapered portion TD1 are connected, so that the ink flow from the flow path PI1 to the outlet flow path H2 of the end portions 273a and 273b is smoother. can do.

The action and effect of the flow path structure G1 of the second embodiment will be described in comparison with the second comparative example. FIG. 18 is an enlarged view of a partial cross section of the flow path structure G1 in the second comparative example in which the inclined surface TP1 and the tapered portion TD1 are not formed, and FIG. 19 is a second view in which the inclined surface TP1 and the tapered portion TD1 are formed. It is the figure which enlarged the partial cross section of the flow path structure G1 in embodiment.

As shown in the second comparative example of FIG. 18, when the inclined surface TP1 and the tapered portion TD1 are not formed, not only the branch points of both ends 273a and 273b of the flow path PI1 but also both ends 273a of the flow path PI1. Ink stagnation also occurs at the branch point between 273b, and bubble Bu tends to stay. This is because the ink flow along the flow path PI1 is pulled by the outlet flow path H2 at each branch point, so that the portion facing each outlet flow path H2 (the upper part of the flow path PI1 at the branch point in FIG. 18). This is because ink stagnation is likely to occur.

On the other hand, as shown in FIG. 19, in the second embodiment, the inclined surface TP1 and the tapered portion TD1 that are inclined in the flow direction of the flow path PI1 are formed at both ends 273a and 273b of the flow path PI1. Therefore, a flow is formed along the inclined surface TP1 and the tapered portion TD1. Further, at the branch point between the ends 273a and 273b of the flow path PI1, an inclined surface TP1 and a tapered portion TD1 that incline in the flow direction of the flow path PI1 are formed, so that the liquid flowing through the flow path PI1 A part of the inclined surface TP1 is directed toward the tapered portion TD1, and a flow along the inclined surface TP1 and the tapered portion TD1 is formed. As a result, stagnation of ink is suppressed not only at both end portions 273a and 273b of the flow path PI1 but also at each branch point, and bubbles are easily discharged from each outlet flow path H2. Thereby, the discharge property of air bubbles at each branch point can be improved.

Moreover, in the second embodiment, as in the first embodiment, all the flow path pipes DI1 including the pipe surface (outer circumference) are arranged so as to be included in the region of the flow path PI1 in a plan view. Therefore, it is possible to reduce the welding unevenness of the welding surface W due to the laser welding forming the flow path PI1. As described above, in the second embodiment, it is possible to improve the dischargeability of air bubbles at each branch point and reduce welding unevenness due to laser welding.

In particular, the pipe surface of the flow path pipe DI1 will be included in the region of each flow path PI1 without forming the inclined surface TP1 as described above on the wall surface of the end portion 273a and 273b of the flow path PI1. If so, as shown in FIG. 18, it is necessary to extend both ends 273a and 273b of the flow path PI1 to the downstream side of the outlet flow path H2 by the amount of the pipe surface (outer circumference) of the flow path pipe DI1. .. Therefore, stagnation of ink is likely to occur in the end portions 273a and 273b of the flow path PI1 that extend downstream from the outlet flow path H2. In this regard, by forming the inclined surface TP1 as described above on the wall surface of the end portions 273a and 273b of the flow path PI1, it is possible to suppress the stagnation of ink in the end portions 273a and 273b of the flow path PI1. Therefore, the bubble discharging property can be effectively improved.

Further, as shown in the enlarged view of FIG. 15, in each protrusion 274, the inclination angle θP1 of the inclined surface TP1 on the upstream side with respect to the flow direction of the flow path PI1 is the inclination on the downstream side with respect to the flow direction of the flow path PI1. It is preferably larger than the inclination angle θP2 of the surface TP2. By doing so, the ink flowing through the flow path PI1 can be easily flowed toward the outlet flow path H2. As a result, the effect of suppressing stagnation at each branch point can be enhanced, and bubbles are more easily discharged from the outlet flow path H2, so that the discharge property of bubbles at each branch point can be further improved. Looking at this point from the inclined surface TP2 on the downstream side of each protrusion 274, the inclination angle θP2 of the inclined surface TP2 on the downstream side is smaller than the inclination angle θP1 of the inclined surface TP1 on the upstream side, so that the flow path PI1 Of these, the flow of ink flowing downstream of each protrusion 274 becomes smoother, and the stagnation of the liquid flowing downstream of the protrusion 274 can be effectively reduced.

In the second embodiment, the case where both the inclined surface TP1 and the tapered portion TD1 are formed at each branch point of the flow path PI1 and the outlet flow path H2 has been described as an example, but the present invention is not limited to this. Instead, only one of the inclined surface TP1 and the tapered portion TD1 may be formed. This also makes it possible to suppress the stagnation of each branch point as compared with the case where the inclined surface TP1 and the tapered portion TD1 are not provided, so that air bubbles can be easily discharged.

Further, the shape of the enlarged diameter portion 284 of the outlet flow path H2 of the flow path structure G1 is not limited to that shown in FIG. For example, as shown in the modified example of FIG. 20, when the tapered portion TD1 extending downstream of the flow path PI1 is used as the first tapered portion in the enlarged diameter portion 284 of the outlet flow path H2, not only the first tapered portion TD1 but also the tapered portion TD1 is used. A second tapered portion TD2 extending on the opposite side, that is, on the upstream side of the flow path PI1, may be provided. That is, the second tapered portion TD2 is a portion of the inner peripheral surface of the enlarged diameter portion 284 on the upstream side of the flow path PI1, and has a conical surface that gradually expands toward the second facing surface 282 with the first substrate 27. The shape is halved.

According to this, since the cross-sectional area of the enlarged diameter portion 284 of the outlet flow path H2 can be increased, it is possible to make it easier for ink to flow from the flow path PI1 to the outlet flow path H2. In this case, as shown in the enlarged view of FIG. 20, it is preferable that the inclination angle θD1 of the first tapered portion TD1 with respect to the outlet flow path H2 is larger than the inclination angle θD2 of the second tapered portion TD2. As a result, the cross-sectional area of the outlet flow path H2 is prevented from becoming too large as compared with the case where the inclination angle θD1 of the first tapered portion TD1 and the inclination angle θD2 of the second tapered portion TD2 are set to the same inclination angle. Therefore, it is possible to suppress a decrease in the flow velocity. In this way, it is possible to make it easier for the ink to flow from the flow path PI1 to the outlet flow path H2 while suppressing the decrease in the flow velocity, so that the discharge property of bubbles can be further improved.

Further, in the flow path structure G1 shown in FIG. 15, the case where the cross-sectional area of the flow path PI1 in the cross section orthogonal to the flow direction of the flow path PI1 is the same between the branch points has been described as an example. The cross-sectional area of the flow path PI1 on the downstream side of the protrusion 274 may be smaller than the cross-sectional area of the flow path PI1 on the upstream side of the protrusion 274. According to this, the cross-sectional area of the flow path PI1 between each branch point can be reduced from the upstream side to the downstream side of the flow path PI1.

When the cross-sectional area of the flow path PI1 between the branch points is the same from the upstream side to the downstream side of the flow path PI1, the flow velocity of the ink flowing through the flow path PI1 decreases as it passes through the protrusions and branch points, so that the bubble discharge property Will also decline. Therefore, as described above, by reducing the cross-sectional area of the flow path PI1 between the branch points from the upstream side to the downstream side of the flow path PI1, it is possible to suppress a decrease in the flow velocity on the downstream side of the protrusion 274. As a result, the dischargeability of air bubbles on the downstream side of the protrusion 274 can be improved.

In this case, for example, the cross-sectional area of the flow path PI1 can be changed by changing the height of the flow path PI1 or the width of the flow path PI1 in the cross section orthogonal to the flow direction of the flow path PI1. Specifically, for example, in another modification of FIG. 21, in the flow path structure G1 of FIG. 15, the height of the flow path PI1 on the downstream side of the protrusion 274 is the height of the flow path PI1 on the upstream side of the protrusion 274. It is designed to be lower than the height. The height of the flow path PI1 here is the surface on the positive side in the Z direction of the inner wall surface of the space constituting the flow path PI1 in the cross section along the flow direction of the flow path PI1 (the flow path shown in FIG. 22 to be described later). At the height from the second facing surface 282) of the second substrate 28 which is the lower surface of the PI1 to the surface on the negative side in the Z direction (the bottom surface 273e of the flow path groove 273 which is the upper surface of the flow path PI1 shown in FIG. 22 described later). is there.

In the flow path structure G1 of FIG. 21, the height hp1 of the flow path PI1 on the downstream side of the protrusion 274 is a protrusion between the inlet flow path H1 on the upstream side of the flow path PI1 and the end portion 273a on the downstream side. The height of the flow path PI1 on the upstream side of the portion 274 is set to be lower than the height hp0. Further, between the inlet flow path H1 on the upstream side of the flow path PI1 and the end portion 273b on the downstream side, the height of the flow path PI1 between the protrusions 274 is set to hp0, hp1, from the upstream side to the downstream side. It is gradually lowered to hp2 and hp3 (hp0> hp1> hp2> hp3). According to this, the cross-sectional area of the flow path PI1 between the branch points can be reduced from the upstream side to the downstream side of the flow path PI1. As a result, it is possible to suppress a decrease in the flow velocity on the downstream side of each protrusion 274, so that the discharge of air bubbles on the downstream side of each protrusion 274 can be improved.

Further, also in the flow path structure G1 of FIG. 21, the pipe surface (outer circumference) of the flow path pipe DI1 of the outlet flow path H2 is within the region of the flow path PI1 surrounded by the welding surface, as in the first embodiment. I am trying to be included. As a result, as in the first embodiment, the welding surface surrounding the flow path PI1 can be prevented from overlapping the pipe surface of the flow path pipe DI1, so that the welding unevenness of the welding surface formed by laser welding can be prevented. It can be effectively reduced.

Moreover, when the cross-sectional area of the flow path PI1 is adjusted by the height of the flow path PI1 as in the flow path structure G1 of FIG. 21, the cross-sectional area of the flow path PI1 is adjusted by the width of the flow path PI1. The area of the flow path PI1 surrounded by the welding surface is not narrowed as compared with the above. If the width of the flow path PI1 is adjusted, the flow path pipe DI1 is adjusted to the width of the flow path PI1 so that the welding surface surrounding the flow path PI1 does not overlap the pipe surface of the flow path pipe DI1. May need to be adjusted to the size of. In this regard, according to the flow path structure G1 of FIG. 21, the welding surface surrounding the flow path PI1 can be adjusted only by the height of the flow path PI1 without changing the width of the flow path PI1. The effect is great in that it is not necessary to adjust the size of the flow path pipe DI1 according to the width of the flow path PI1 so as not to overlap the pipe surface.

When adjusting the cross-sectional area of the flow path PI1 with the height of the flow path PI1, as shown in FIG. 21, the inclination of the inclined surface TP1 on the upstream side of the protrusion 274 is set to the height of the flow path PI1. You may change it accordingly. In FIG. 21, the lower the height of the flow path PI1, the smaller the inclination of the inclined surface TP1 on the upstream side of the protrusion 274. As a result, even if the height of the flow path PI1 changes, for example, the virtual line y (see the enlarged view of FIG. 15) extended along the inclination of the inclined surface TP1 on the upstream side of the protrusion 274 is always the enlarged diameter portion. It can be adjusted to pass through the tapered portion TD1 of 284.

Further, in the flow path structure G1 of FIG. 21, the case where the inclined surface TP1 arranged at each branch point is formed on the upstream side of the protrusion 274 is given as an example, but the present invention is not limited to this. When adjusting the height of the flow path PI1 between each branch point as shown in FIG. 21, a step is formed at each branch point where the height of the flow path PI1 changes, so that the step is formed on the upstream side of this step. An inclined surface TP1 may be formed on the wall surface.

Further, in the flow path structure G1 of FIG. 21, the case where the height of the flow path PI1 between the branch points is adjusted has been described as an example, but the height of the protrusion 274 may be adjusted. .. This also makes it possible to suppress a decrease in the flow velocity on the downstream side of each protrusion 274. The height of the protrusion 274 here is from the formation surface of the protrusion 274 in the cross section along the flow direction in the flow path PI1 (the bottom surface 273e of the flow path groove 273 which is the upper surface of the flow path PI1 shown in FIG. 22). It is the height of the protrusion 274 to the top 274a.

For example, in the flow path structure G1 shown in FIG. 22, the height of the protrusion 274 of the flow path structure G1 shown in FIG. 15 is changed. Specifically, the height of each protrusion 274 from the inlet flow path H1 on the upstream side of the flow path PI1 to the end portion 273b on the downstream side gradually increases to ht1, ht2, ht3 (ht1 <ht2 <ht3). I am doing it. The higher the height of the protrusion 274, the narrower the cross-sectional area of the flow path PI1 at the branch portion. Therefore, the cross-sectional area of the flow path PI1 at each branch point increases from the upstream side to the downstream side of the flow path PI1. It can be adjusted to gradually narrow. As a result, it is possible to suppress a decrease in the flow velocity on the downstream side of each protrusion 274, so that the discharge of air bubbles on the downstream side of each protrusion 274 can be improved.

By the way, regarding the flow velocity of the ink flowing through the flow path PI1, as described above, the flow velocity decreases from the upstream side to the downstream side of the flow path PI1 as it passes through each branch point. Therefore, it is preferable to adjust the height of the protrusion 274 according to the flow velocity between the branch points in the flow path PI1. In this case, the higher the height of the protrusion 274, the more the decrease in the flow velocity can be suppressed, so that the exhaust property of the bubbles can be improved accordingly. However, if the height of the protrusion 274 is made too high, the area of the wall surface (inclined surface TP1) of the protrusion 274 in which the ink flow in the flow path PI1 comes into contact becomes large, so that the pressure loss increases. On the contrary, the flow velocity decreases. Therefore, in order to suppress an increase in pressure loss, it is preferable to adjust the height of the protrusion 274 so that it does not become too large.

Therefore, in the following, a preferable range of the height of the protrusion 274 at each branch point will be described in order to achieve both the effect of enhancing the exhaust property of such bubbles and the effect of suppressing the increase in pressure loss. First, it is assumed that the flow velocities between the branch points in the flow path PI1 are the same. Assuming that the number of branch points in the flow path PI1 from the upstream side to the downstream side is N (1 ≦ N), the number of tributaries between each branch point is N + 1, which is the Mth (1 ≦ N) from the upstream side. The flow velocity V (M) at the branch point of M ≦ N) can be expressed by the following mathematical formula (1), and the total flow velocity V (M + 1) at the M + 1th branch point on the downstream side of the Mth is as follows. It can be expressed by the mathematical formula (2).

V (M) = [1 / (N + 1)] x [(N + 1)-(M-1)] = (N-M + 2) / (N + 1)
... (1)

V (M + 1) = [1 / (N + 1)] x [(N + 1) -M] = (N-M + 1) / (N + 1)
... (2)

The ratio X of the height of the protrusion 274 to the height hp of the path PI1 in the flow path PI1 can be expressed by the following mathematical formula (3).

1-V (M) ≤ X ≤ 1-V (M + 1) ... (3)

By substituting the above formulas (1) and (2) into the above formula (3), the height ratio X of the protrusion 274 can be expressed by the following formula (4).

1- (N-M + 2) / (N + 1) ≤ X ≤ 1- (N-M + 1) / (N + 1) ... (4)

The preferable range of the height of the protrusion 274 at each branch point can be calculated by the above mathematical formula (4). For example, in the flow path structure G1 shown in FIG. 22, the preferable range of the height of each protrusion 274 from the inlet flow path H1 on the upstream side of the flow path PI1 to the end portion 273b on the downstream side is calculated as follows. Become. First, since there are three branch points from the inlet flow path H1 on the upstream side of the flow path PI1 to the end portion 273b on the downstream side, N = 3, so the tributaries between the branch points are N + 1 = 4. is there.

Therefore, the ratios of the heights ht1, ht2, and ht3 of the protrusions 274 to the height hp of the flow path PI1 X1, X2, and X3 substitute N = 3 in the above equation (4), respectively, and M = 1, 2, The following mathematical formulas (5), (6), and (7) are obtained by substituting 3 respectively.

0 ≦ X1 ≦ 1/4 ・ ・ ・ (5)

1/4 ≤ X2 ≤ 2/4 ... (6)

2/4 ≤ X1 ≤ 3/4 ... (7)

According to this, the heights ht1, ht2, and ht3 of each protrusion 274 are set within the range of the above mathematical formulas (5), (6), and (7) with respect to the height hp of the flow path PI1. In this way, by setting the height of each protrusion 274 with respect to the height hp of the flow path PI1 within the range of the above formula (4), the effect of improving the exhaust property of air bubbles and the increase of pressure loss are suppressed. It is possible to achieve both the effects of

Depending on the cross-sectional shape of the flow path PI1, the cross-sectional area of the flow path PI1 may be too small or too large even if the heights of the protrusions 274 are the same. Therefore, it is preferable to set the height of each protrusion 274 within the range of the above mathematical formula (4). FIG. 23 shows the relationship between the cross-sectional shape of the flow path PI1 and the height of the protrusion 274 in the cross section of the flow path PI1 along the flow direction. The left side of FIG. 23 is a case where the cross-sectional shape of the flow path PI1 is rectangular, and the center of FIG. 23 is a shape in which the cross-sectional shape of the flow path PI1 is convex upward (a portion where the width of the flow path narrows upward). This is the case of having a shape). The right side of FIG. 23 is a case where the cross-sectional shape of the flow path PI1 is convex downward (a shape having a portion where the width of the flow path is narrowed downward).

For example, when the cross-sectional shape of the flow path PI1 is convex downward (right side in FIG. 23), the width of the flow path PI1 is narrower on the lower surface side than on the upper surface side, so that the cross-sectional shape of the flow path PI1 is Even if the protrusion 274 having the same height as the case of the rectangle (left side in FIG. 23) is formed, the cross-sectional area of the flow path PI1 becomes small. Therefore, as shown in FIG. 23, when the cross-sectional shape of the flow path PI1 is convex downward (right side of FIG. 23), the cross-sectional shape of the flow path PI1 is rectangular (left side of FIG. 23). Also, by lowering the height of the protrusion 274, it is possible to secure the same cross-sectional area of the flow path PI1 as in the case where the cross-sectional shape of the flow path PI1 is rectangular (left side in FIG. 23).

In the second embodiment, the case where the flow path groove 273 constituting the flow path PI1 is formed only on the first substrate 27 has been described as an example, but the present invention is not limited to this, and only on the second substrate 28. It may be formed, and the flow path grooves forming the flow path PI1 are formed on both the first substrate 27 and the second substrate 28, and the first substrate 27 and the second substrate 28 are formed so that the flow path grooves face each other. May be opposed to each other and laminated to be joined. However, when the flow path groove 273 constituting the flow path PI1 is formed on only one of the first substrate 27 and the second substrate 28, it is formed on both the first substrate 27 and the second substrate 28. In comparison with the above, even if the first substrate 27 and the second substrate 28 are misaligned when the flow path grooves of the first substrate 27 and the second substrate 28 are opposed to each other and laminated, the expected first flow A road can be formed.

The printing device 100 illustrated in each of the above embodiments can be used in various devices such as a facsimile machine and a copier, in addition to a device dedicated to printing. However, the application of the liquid injection device of the present invention is not limited to printing. For example, a liquid injection device that injects a solution of a coloring material is used as a manufacturing device for forming a color filter of a liquid crystal display device. Further, a liquid injection device for injecting a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board.

100 ... printing device, 10 ... control device, 12 ... transport mechanism, 14 ... liquid injection head, 142 ... housing, 16 ... pump, 18 ... liquid container, 23 ... mounting hole, 27 ... first substrate (light absorbing member) ), 272a, 272b ... facing surface, 273 ... flow path groove, 273a, 273b ... end, 273e ... bottom surface, 274 ... protrusion, 274a top, 28 ... second substrate (light transmitting member), 282b ... second Facing surface, 283a ... Flow path groove, 283b ... Flow path groove, 284 ... Diameter expansion part, 32 ... Flow path forming plate, 322 ... Opening, 52 ... Filter part, 526 ... Filter, 54 ... Communication member, 542 ... Penetration Hole, 56 ... Basic wiring board, 58 ... Fixed plate, 582 ... Opening, 60 ... Liquid distribution part, 60A ... Supply port, 70 ... Injection head part, 71 ... Flow path forming board, 712 ... Opening, 714 ... Supply Flow path, 716 ... Communication flow path, 72 ... Pressure chamber forming substrate, 722 ... Opening, 73 ... Vibrating plate, 732 ... piezoelectric element, 74 ... Nozzle plate, 75 ... Compliance substrate, 752 ... Sealing plate, 754 ... Support Body, 76 ... Protective plate, 762 ... Slit, 77 ... Support, 771 ... Supply port, 772 ... Recess, 774 ... Opening, 775 ... Lid, 776 ... Slit, 78 ... Individual wiring board, hp, hp0, hp1 , Hp2, hp3 ... Flow path height (first flow path height), ht1, ht2, ht3 ... Projection height, y ... Virtual line, A1, A2 ... Air, Bu ... Bubble, C ... Pressure Chamber, DI1, DA1 ... Flow tube, DI2 ... Flow tube, F ... Filter, G1 ... Flow structure, G2 ... Flow control, G3 ... Liquid injection, H1 ... Inlet flow path, H2 ... Each outlet Flow path, H2 ... Outlet flow path, I ... Ink, L ... Laser light, La, Lb ... Laser light, L'La' ... Laser light, M ... Print medium, N ... Nozzle, PI1, PA1 ... Flow path, R ... Liquid storage chamber, SI1, SA1 ... Flow tube, SI3 ... Supply port, TD1 ... 1st tapered part, TD2 ... 2nd tapered part, TP1 ... 1st inclined surface, TP2 ... 2nd inclined surface, U2 ... Flow path Control unit, U3 ... Liquid injection unit, W, W'... Welding surface, Wa, Wb ... Welding surface, θD1, θD2 ... Tilt angle, θP1, θP2 ... Tilt angle.

Claims (21)

A flow path structure that forms a flow path for a liquid.
A light-absorbing member that absorbs laser light,
A light-transmitting member that is joined to the light-absorbing member and has transparency to the laser beam,
A first flow path surrounded by a welding surface to which the light absorbing member and the light transmitting member are welded,
A second flow path formed in a flow path tube protruding from the surface of the light transmissive member on the opposite side of the welding surface and communicating with the first flow path is provided.
In a plan view from a direction orthogonal to the welding surface, the entire outer circumference of the flow path pipe is included in the region of the first flow path .
It is provided with a third flow path that is formed in a flow path tube that protrudes to the opposite side of the flow path tube from which the second flow path is formed with respect to the welding surface and communicates with the first flow path.
The number of flow path pipes forming the third flow path is smaller than the number of flow path pipes forming the second flow path.
The cross-sectional area of the third flow path is larger than the cross-sectional area of the second flow path.
A flow path structure in which the outer periphery of the flow path pipe forming the third flow path overlaps the welding surface surrounding the first flow path in a plan view from a direction orthogonal to the welding surface .
The flow path structure according to claim 1, wherein the second flow path includes a diameter-expanded portion having a first tapered portion that extends in a tapered shape toward the downstream side of the first flow path toward the first flow path.
A flow path structure that forms a flow path for a liquid.
A light-absorbing member that absorbs laser light,
A light-transmitting member that is joined to the light-absorbing member and has transparency to the laser beam,
A first flow path surrounded by a welding surface to which the light absorbing member and the light transmitting member are welded,
A second flow path formed in a flow path tube protruding from the surface of the light transmissive member on the opposite side of the welding surface and communicating with the first flow path is provided.
In a plan view from a direction orthogonal to the welding surface, the entire outer circumference of the flow path pipe is included in the region of the first flow path.
The second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path.
The enlarged diameter portion of the second flow path further has a second tapered portion that tapers toward the upstream side of the first flow path toward the first flow path.
The inclination angle of the first tapered portion with respect to the second flow path is larger than the inclination angle of the second tapered portion with respect to the second flow path.
Channel structure.
The flow path structure according to claim 2 or 3, wherein the end of the enlarged diameter portion of the second flow path is open to the surface of the light transmitting member facing the light absorbing member.
A flow path structure that forms a flow path for a liquid.
A light-absorbing member that absorbs laser light,
A light-transmitting member that is joined to the light-absorbing member and has transparency to the laser beam,
A first flow path surrounded by a welding surface to which the light absorbing member and the light transmitting member are welded,
A second flow path formed in a flow path tube protruding from the surface of the light transmissive member on the opposite side of the welding surface and communicating with the first flow path is provided.
In a plan view from a direction orthogonal to the welding surface, the entire outer circumference of the flow path pipe is included in the region of the first flow path.
The second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path.
A plurality of the second flow paths are formed from the inlet flow path communicating with the first flow path to the downstream side, and the plurality of second flow paths are arranged at the downstream end of the first flow path. Includes a flow path and a flow path arranged between the downstream end of the first flow path and the inlet flow path.
The flow of the light absorbing member is at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path among the plurality of second flow paths. A flow path structure in which a protrusion protruding toward the enlarged diameter portion of the road is formed.
The first flow path is formed from one end to the other.
The inlet flow path communicating with the first flow path is arranged between the one end portion and the other end portion.
The flow path structure according to any one of claims 2 to 5, wherein the second flow path is arranged at both the one end portion and the other end portion.
It is provided with two light transmitting members that are joined to the light absorbing member and have transparency to the laser light.
The light absorbing member is sandwiched between the two light transmitting members and laminated.
The flow path structure according to claim 5 or 6 , wherein the flow path tube of the second flow path is formed in one or both of the two light transmitting members.
The flow path structure according to claim 7 , wherein the flow path tube of the second flow path is formed in one of the two light transmitting members, and the flow path tube of the third flow path is formed in the other. ..
The flow path structure according to claim 7 or 8 , wherein the light absorbing member is provided with a filter interposed between the two light transmitting members.
With the flow path structure according to any one of claims 1 to 9 .
A liquid injection head including a nozzle for injecting a liquid from the flow path structure by driving a driving element.
A transport mechanism that transports media and
A liquid injection device comprising the liquid injection head according to claim 10 , which injects a liquid into the medium.
A method for manufacturing a flow path structure that forms a flow path for a liquid.
A flow path groove of the first flow path is provided on the facing surface of either one or both of the light absorbing member having absorption to laser light and the light transmitting member having transparency to the laser light. The process of forming and
In the light transmitting member, a flow path tube is formed so as to protrude from the surface opposite to the surface facing the light absorbing member, and a second flow path communicating with the first flow path is provided in the flow path tube. The process of forming and
A step of laminating the light absorbing member and the light transmitting member so that their facing surfaces are in contact with each other.
The first flow path is formed by irradiating the laser beam toward the light transmissive member to form a welding surface surrounding the flow path groove without overlapping the entire outer circumference of the flow path tube in the irradiation direction. With the process of forming ,
It is provided with a third flow path that is formed in a flow path tube that protrudes to the opposite side of the flow path tube from which the second flow path is formed with respect to the welding surface and communicates with the first flow path.
The number of flow path pipes forming the third flow path is smaller than the number of flow path pipes forming the second flow path.
The cross-sectional area of the third flow path is larger than the cross-sectional area of the second flow path.
The outer circumference of the flow path pipe forming the third flow path overlaps the welding surface surrounding the first flow path in a plan view from a direction orthogonal to the welding surface.
A method for manufacturing a flow path structure.
The flow path structure according to claim 12 , wherein the second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path. Production method.
A method for manufacturing a flow path structure that forms a flow path for a liquid.
A flow path groove of the first flow path is provided on the facing surface of either one or both of the light absorbing member having absorption to laser light and the light transmitting member having transparency to the laser light. The process of forming and
In the light transmitting member, a flow path tube is formed so as to protrude from the surface opposite to the surface facing the light absorbing member, and a second flow path communicating with the first flow path is provided in the flow path tube. The process of forming and
A step of laminating the light absorbing member and the light transmitting member so that their facing surfaces are in contact with each other.
The first flow path is formed by irradiating the laser beam toward the light transmissive member to form a welding surface surrounding the flow path groove without overlapping the entire outer circumference of the flow path tube in the irradiation direction. With the process of forming,
The second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path.
The enlarged diameter portion of the second flow path further has a second tapered portion that tapers toward the upstream side of the first flow path toward the first flow path.
A method for manufacturing a flow path structure , wherein the inclination angle of the first tapered portion with respect to the second flow path is larger than the inclination angle of the second tapered portion with respect to the second flow path.
The end of the enlarged diameter portion of the second flow path is open to the surface of the light transmitting member facing the light absorbing member.
The method for manufacturing a flow path structure according to claim 13 or 14 .
A method for manufacturing a flow path structure that forms a flow path for a liquid.
A flow path groove of the first flow path is provided on the facing surface of either one or both of the light absorbing member having absorption to laser light and the light transmitting member having transparency to the laser light. The process of forming and
In the light transmitting member, a flow path tube is formed so as to protrude from the surface opposite to the surface facing the light absorbing member, and a second flow path communicating with the first flow path is provided in the flow path tube. The process of forming and
A step of laminating the light absorbing member and the light transmitting member so that their facing surfaces are in contact with each other.
The first flow path is formed by irradiating the laser beam toward the light transmissive member to form a welding surface surrounding the flow path groove without overlapping the entire outer circumference of the flow path tube in the irradiation direction. With the process of forming,
The second flow path includes a diameter-expanded portion having a first tapered portion that tapers toward the downstream side of the first flow path toward the first flow path.
A plurality of the second flow paths are formed from the inlet flow path communicating with the first flow path to the downstream side, and the plurality of second flow paths are arranged at the downstream end of the first flow path. Includes a flow path and a flow path arranged between the downstream end of the first flow path and the inlet flow path.
The flow of the light absorbing member is at a position facing the flow path arranged between the downstream end of the first flow path and the inlet flow path among the plurality of second flow paths. A method for manufacturing a flow path structure in which a protrusion protruding toward an enlarged diameter portion of a road is formed.
The first flow path is formed from one end to the other.
The inlet flow path communicating with the first flow path is arranged between the one end portion and the other end portion.
The method for manufacturing a flow path structure according to any one of claims 13 to 16 , wherein the second flow path is arranged at both the one end portion and the other end portion.
It is provided with two light transmitting members that are joined to the light absorbing member and have transparency to the laser light.
The light absorbing member is sandwiched between the two light transmitting members and laminated.
The method for manufacturing a flow path structure according to claim 16 or 17 , wherein a flow path tube of the second flow path is formed in one or both of the two light transmitting members.
The flow path structure according to claim 18 , wherein the flow path tube of the second flow path is formed in one of the two light transmitting members, and the flow path tube of the third flow path is formed in the other. Manufacturing method.
The method for manufacturing a flow path structure according to claim 18 or 19 , wherein the light absorbing member is provided with a filter interposed between the two light transmitting members.
The angle of the laser beam irradiation direction with respect to the welding surface is constant.
A method for manufacturing a flow path structure according to any one of claims 12 to 20.

Images