Static mixer and paste injector

Abstract

In order to provide a static mixer and a paste injector with which it is possible to adjust, with a simple structure, the pushing force of a plunger while preventing air bubbles from being mixed into a dental material being discharged, a static mixer (7) includes: a plurality of paste passages (29, 29') that are disposed side by side on a circumference centered on a central axis (CA) of a syringe (3), and that extend in a longitudinal direction (X); an intermediate passage (31); and a mixing passage (33) that extends centered on the central axis (CA). The inner circumferential surface of each of the plurality of paste passages (29, 29') has a tapered portion formed in a tapered shape approaching the central axis (CA) toward outflow holes (29B, 29B') from inflow holes (29A, 29A') in distal surfaces (29C, 29C'), and the opening area of the inflow holes (29A, 29A') is greater than the opening area of the outflow holes (29B, 29B').

Description

Static mixer and paste injector

[0001] The present invention relates to a static mixer and a paste injector.

[0002] Dental materials are known that are made up of multiple types of pastes that are mixed together immediately before use. To inject such dental materials into a predetermined location, there are paste injectors that mix and dispense multiple types of pastes.

[0003] The paste injector includes a syringe containing multiple types of paste, a plunger for pushing out the paste, and a static mixer attached to the discharge portion of the syringe.

[0004] Static mixers are disclosed, for example, in Patent Documents 1 and 2.

[0005] Japanese Patent Application Laid-Open No. 11-99325 International Publication No. 2018 / 057503

[0006] A user of a paste injector must hold the syringe with one hand and push the plunger to dispense an appropriate amount of dental material little by little. In other words, if the force required to push the plunger is too great, it will be difficult to push the plunger, and if the force is too small, more dental material will be dispensed than necessary.

[0007] Furthermore, if air bubbles are mixed in, the dental material cannot be prepared properly, so it is necessary to prevent air bubbles from being mixed in the paste flow path.

[0008] For example, the static mixer described in Patent Document 1 adjusts the pushing force of the plunger by forming a step in the paste passage as shown in Fig. 2. However, in this case, there is a problem in that air bubbles are likely to be trapped in the step.

[0009] The static mixer described in Patent Document 2 adjusts the plunger pushing force by curving the paste passage as shown in Fig. 4. However, this method has the problem that air bubbles are likely to form at the change point where the paste flow direction changes, and the structure is complicated.

[0010] An object of the present invention is to provide a static mixer and a paste injector that have a simple structure and are capable of adjusting the plunger pressing force while preventing air bubbles from being mixed into the dental material being dispensed.

[0011] The static mixer of the present invention comprises a syringe having an inlet and an outlet, a plurality of paste passages through which the plurality of pastes individually housed in the syringe extend in the longitudinal direction, the plurality of paste passages having inlet and outlet holes, an intermediate passage for guiding the plurality of pastes discharged from the outlet holes to a joining position, and a mixing passage through which the plurality of pastes joined at the joining position pass while being mixed. To achieve the above object, the plurality of paste passages are arranged side by side on a circumference centered on a central axis of the syringe and extend in the longitudinal direction, and each of the plurality of paste passages has an inner peripheral surface, at least a portion of a distal surface away from the central axis, tapered toward the central axis as it moves from the inlet to the outlet, and the opening area of ​​the inlet hole is larger than the opening area of ​​the outlet hole. The paste injector of the present invention comprises the static mixer described above.

[0012] With this configuration, the static mixer and paste injector of the present invention do not trap air bubbles in the paste flow path, preventing air bubbles from getting mixed into the dental material. In addition, the amount of dental material dispensed can be easily adjusted by adjusting the force with which the plunger is pressed.

[0013] It is a perspective view of the paste injector equipped with the static mixer of Example 1. It is an exploded perspective view of the paste injector of Example 1. It is a cross-sectional view of the static mixer fixed to the tip of the syringe of Example 1, cut in the width direction at a position passing through the central axis extending in the longitudinal direction. It is a front view of the syringe of Example 1. It is a side view of the syringe of Example 1. It is a plan view of the syringe of Example 1. It is a bottom view of the syringe of Example 1. It is a cross-sectional view taken along line V-V shown in FIG. 4C. It is an end view taken along line VI-VI shown in FIG. 4A. It is a front view of the plunger body of Example 1. It is a side view of the plunger body of Example 1. It is a plan view of the plunger body of Example 1. It is a bottom view of the plunger body of Example 1. It is a cross-sectional view taken along line VIII-VIII shown in FIG. 7A. It is a perspective view of the elastic body holder of Example 1. It is a bottom view of the elastic body holder of Example 1. It is a cross-sectional view of the elastic body holder with an O-ring attached to the annular groove portion in the paste injector of Example 1, cut in the width direction orthogonal to the longitudinal direction at the neck portion. It is a cross-sectional view (schematic view) of the elastic body holder with an O-ring attached to the annular groove portion in the paste injector of Example 1, when cut in the width direction orthogonal to the longitudinal direction at the neck portion in a state where it is inserted into the paste storage chamber of the syringe, and cross-sectional views (schematic views) when viewed from the front direction and the side direction at that time. It is a perspective view of the mixing chip main body portion of Example 1. It is a bottom view of the mixing chip main body portion of Example 1. It is a cross-sectional view taken along line XIII-XIII shown in FIG. 12B. It is a perspective view of the mixer housing of Example 1. It is a bottom view of the mixer housing of Example 1. It is a cross-sectional view taken along line XV-XV shown in FIG. 14B. It is a front view of the mixer outer body of Example 1. It is a plan view of the mixer outer body of Example 1. It is a bottom view of the mixer outer body of Example 1. It is a cross-sectional view taken along line XVII-XVII shown in FIG. 16B. It is a cross-sectional view taken along line XVIII-XVIII shown in FIG. 16A. It is a perspective view of the inner member of the cap of Example 1. It is a bottom view of the inner member of the cap of Example 1. It is a cross-sectional view taken along line XX-XX shown in FIG. 19B. It is a front view of the outer body of the cap of Example 1. It is a plan view of the outer body of the cap of Example 1. It is a bottom view of the outer body of the cap of Example 1. It is a cross-sectional view taken along line XXII-XXII shown in FIG. 21B.21A. A cross-sectional view taken along line XXIII-XXIII shown in FIG. 21A. A diagram showing a state prior to placing and fixing the static mixer over the syringe in the paste injector of Example 1. A bottom view of the static mixer after only the mixer exterior has rotated in the paste injector of Example 1. An exploded perspective view of the paste injector of Example 2. A cross-sectional view of the static mixer fixed to the tip of the syringe of Example 2, cut in the width direction at a position passing through the central axis extending in the longitudinal direction. A perspective view of the tip of the syringe of Example 2. A plan view of the syringe of Example 2. A main part of the cross-sectional view taken along line XXVIII-XXVIII shown in FIG. 28B. A perspective view of the mixing tip main body of Example 2. A bottom view of the mixing tip main body of Example 2. A cross-sectional view taken along line XXIX-XXIX shown in FIG. 29B. A perspective view of the mixer housing of Example 2. A cross-sectional view taken along line XXX-XXX shown in FIG. 30A. A front view of the mixer exterior of Example 2. A side view of the mixer exterior of Example 2. 31C. FIG. 32C is a plan view of a mixer exterior housing of Example 2. FIG. 33C is a bottom view of a mixer exterior housing of Example 2. FIG. 34C is a cross-sectional view taken along line XXXIE-XXXIE shown in FIG. 31C. FIG. 35C is a cross-sectional view taken along line XXXIF-XXXIF shown in FIG. 31C. FIG. 36C is a cross-sectional view taken along line XXXIG-XXXIG shown in FIG. 31A. FIG. 35C is a front view of a cap exterior housing of Example 2. FIG. 36C is a side view of a cap exterior housing of Example 2. FIG. 37C is a bottom view of a mixer exterior housing of Example 2. FIG. 37C is a cross-sectional view taken along line XXXIIE-XXXIIE shown in FIG. 32C. FIG. 38C is a cross-sectional view taken along line XXXIIIF-XXXIIF shown in FIG. 32C. FIG. 38C is a cross-sectional view taken along line XXXIIG-XXXIIG shown in FIG. 32A.

[0014] Hereinafter, embodiments of the static mixer and paste injector of the present invention will be described based on Examples 1 and 2 shown in the drawings.

[0015] (Example 1) <Overall Configuration> Fig. 1 is a perspective view of a paste injector 1 equipped with a static mixer 7 of Example 1, and Fig. 2 is an exploded perspective view of the paste injector 1 of Example 1. In this Example 1, as shown in Fig. 2, a longitudinal direction (X), a width direction (Y), and a thickness direction (Z) are defined for the paste injector 1.

[0016] As shown in Figure 1, the paste injector 1 includes a syringe 3, a plunger 5, a static mixer 7, and a guide tip 9. The paste injector 1 of Example 1 pushes out two types of paste individually filled in the syringe 3 with the plunger 5, mixes them in the static mixer 7 just before use to prepare a dental material, and then injects the paste into a desired location (such as an affected area or a dental filling) via the guide tip 9. The guide tip 9 is a nozzle member that is attached to the static mixer 7 in a fixed fit state as needed. The paste injector 1 can be used even if the guide tip 9 is not attached to the static mixer 7.

[0017] When the paste injector 1 is stored or transported, a cap 11 shown in Fig. 2 is fixed to the tip of the syringe 3 (one end 41A of a syringe body 41 described later) instead of the static mixer 7. In this specification, the static mixer 7 and cap 11 detachably attached to the tip of the syringe 3 (one end 41A of the syringe body 41) are collectively referred to as an attachment member M. The syringe 3, plunger 5, and attachment member M (static mixer 7 or cap 11) extend in the longitudinal direction X shown in Fig. 2 and are assembled with their central axes CA, which pass through the centers of the respective components, aligned.

[0018] The syringe 3 is filled with paste in advance and distributed with the plunger 5 inserted. The plunger 5 is composed of a plunger body 13, an elastic body holder 15 loosely engaged with the tip of the plunger body 13, and an annular O-ring (elastic body) 17 attached to the elastic body holder 15. Here, "loosely engaged" means that the elastic body holder 15 is engaged with the plunger body 13 with sufficient engagement force that the friction between the syringe 3 and the O-ring 17 causes the elastic body holder 15 to come off the plunger body 13. The elastic body holder 15 and the O-ring 17 form the tip of the plunger 5. Of course, the plunger 5 may be an integrated unit that is not separated into the plunger body 13 and the elastic body holder 15. In this case, the annular O-ring 17 may be attached directly to the tip of the plunger 5.

[0019] The static mixer 7 is composed of a mixing tip main body 19, a mixer housing 21, and a mixer exterior body 23.

[0020] The cap 11 is composed of a cap inner member 25 and a cap outer body 27 .

[0021] [Paste Flow Channel] FIG. 3 is a cross-sectional view of the static mixer 7 fixed to the tip of the syringe 3, cut in the width direction Y at a position passing through a central axis CA extending in the longitudinal direction X.

[0022] Within the static mixer 7, a paste flow path is formed by the mixing tip main body 19 and the mixer housing 21. In Example 1, the paste flow path is composed of a paste passage 29, a paste passage 29', an intermediate passage 31, and a mixing passage 33. The paste passages 29, 29' are aligned circumferentially about the central axis CA, are arranged symmetrically along the width direction Y, and each extend in the longitudinal direction X. The mixing passage 33 is located downstream of the paste passages 29, 29' in the paste flow direction, and extends around the central axis CA extending in the longitudinal direction X. The intermediate passage 31 is a passage that connects the paste passages 29, 29' and the mixing passage 33.

[0023] The paste passage 29 is a passage through which the paste discharged from the paste storage chamber 49 of the syringe 3 flows. The paste passage 29 has an inlet hole 29A through which the paste flows and an outlet hole 29B through which the paste flows out, and is formed in the mixing tip main body 19. The opening area of ​​the inlet hole 29A is larger than the opening area of ​​the outlet hole 29B. Furthermore, the opening center point of the outlet hole 29B is set at a position closer to the central axis CA than the opening center point of the inlet hole 29A.

[0024] The inner circumferential surface of the paste passage 29 has a tapered portion on a distal surface 29C away from the central axis CA when viewed in a cross section perpendicular to the thickness direction Z. The tapered portion of the distal surface 29C of Example 1 is formed in a tapered shape that gradually approaches the central axis CA as it extends from the inlet hole 29A to the outlet hole 29B. That is, the tapered portion of Example 1 extends at a constant angle from the inlet hole 29A to the outlet hole 29B. Furthermore, the inner circumferential surface of the paste passage 29 has a proximal surface 29D that is close to the central axis CA when viewed in a cross section perpendicular to the thickness direction Z, extending parallel to the central axis CA from the inlet hole 29A to the outlet hole 29B, and aligned with the central axis CA. Therefore, the cross-sectional area of ​​the paste passage 29 of Example 1 perpendicular to the central axis CA (longitudinal direction X) gradually decreases at a constant rate from the inlet hole 29A to the outlet hole 29B.

[0025] The paste passage 29' is a passage through which the paste discharged from the paste storage chamber 49' of the syringe 3 flows. Since the paste passage 29' has the same configuration as the paste passage 29, the reference numerals of the respective parts of the paste passage 29 are marked with "", and the description thereof will be omitted.

[0026] The paste passages 29 and 29' are formed to have the same size and are symmetrical in the width direction Y around the central axis CA. That is, the inlet hole 29A and the inlet hole 29A' have the same opening area, and the outlet hole 29B and the outlet hole 29B' have the same opening area. When viewed along the central axis CA, the distance from the central axis CA to the center of the inlet hole 29A is the same as the distance from the central axis CA to the inlet hole 29A'. When viewed along the central axis CA, the distance from the central axis CA to the center of the outlet hole 29B is the same as the distance from the central axis CA to the outlet hole 29B'. Furthermore, the inclination angle of the distal surface 29C relative to the central axis CA is the same as the inclination angle of the distal surface 29C' relative to the central axis CA.

[0027] The intermediate passage 31 is a passage that guides the paste flowing out from the outlet holes 29B, 29B' to the joining position JP. In Example 1, a backflow prevention wall 35 is provided between the outlet holes 29B and 29B'. The backflow prevention wall 35 divides the intermediate passage 31 into an outlet hole 29B side and an outlet hole 29B' side, and prevents paste flowing out from one outlet hole 29B (29B') from flowing into the other outlet hole 29B' (29B). Here, the backflow prevention wall 35 stands up from the end face of the mixing tip main body 19 where the outlet holes 29B, 29B' are formed, and extends along the central axis CA to the joining position JP. The backflow prevention wall 35 has curved surfaces 35A, 35A' at its base that direct the paste toward the joining position JP.

[0028] The mixing passage 33 is a passage through which the pastes that meet at the meeting point JP pass while being mixed, and extends around a central axis CA that extends in the longitudinal direction X. The mixing passage 33 is composed of an element housing portion 37 that extends cylindrically in the mixer housing 21, and an element group 39 that extends from the end of the backflow prevention wall 35 and is inserted into the element housing portion 37.

[0029] [Fixing of Mounting Member] The static mixer 7 or the cap 11, which is the mounting member M, is detachably mounted to the tip end portion (one end portion 41A of the syringe body 41) of the syringe 3. The fixing structure will be described below.

[0030] Here, the mounting member M is composed of an inner member IM and an outer casing OM. When the mounting member M is a static mixer 7, the mixing tip main body 19 and the mixer housing 21 form the inner member IM, and the mixer outer casing 23 forms the outer casing OM. When the mounting member M is a cap 11, the cap inner member 25 forms the inner member IM, and the cap outer casing 27 forms the outer casing OM.

[0031] In the static mixer 7, the mixing tip main body 19 and the mixer housing 21 (inner member IM) are disposed inside the mixer exterior body 23 (exterior body OM). The mixing tip main body 19 and the mixer housing 21 are configured to be rotatable around the central axis CA relative to the mixer exterior body 23 within a predetermined angular range. Similarly, in the cap 11, the cap inner member 25 (inner member IM) is disposed inside the cap exterior body 27 (exterior body OM). The cap inner member 25 is configured to be rotatable around the central axis CA relative to the cap exterior body 27 within a predetermined angular range.

[0032] When the tip portion of the syringe 3 (one end 41A of the syringe body 41) is inserted into the exterior body OM via the inner member IM along the central axis CA, the inner member IM becomes unable to rotate relative to the syringe 3, but the exterior body OM is rotatable relative to the syringe 3. When the exterior body OM rotates around the central axis CA in this state, only the exterior body OM rotates relative to the syringe 3, and the mounting member M is fixed to the tip portion of the syringe 3 (one end 41A of the syringe body 41) via the engagement structure.

[0033] The engagement structure has three or more (three in Example 1) engagement pairs each consisting of an engagement portion 45 formed on the syringe 3 and an engaged portion 107 formed on the mixer exterior body 23, which is the exterior body OM, or an engagement pair each consisting of an engagement portion 45 formed on the syringe 3 and an engaged portion 129 formed on the cap exterior body 27, which is the exterior body OM. The detailed configurations of the engagement portion 45, the engaged portion 107, and the engaged portion 129 will be described later.

[0034] <Details of Each Component> [Syringe] Fig. 4A is a front view of the syringe 3, Fig. 4B is a side view, Fig. 4C is a plan view, and Fig. 4D is a bottom view. Fig. 5 is a cross-sectional view taken along line VV shown in Fig. 4C, and Fig. 6 is an end view taken along line VI-VI shown in Fig. 4A.

[0035] The syringe 3 is a cylindrical body extending in the longitudinal direction X, and includes a syringe body 41 , two protrusions 43 , 43 ′, an engagement portion 45 , and a finger hook portion 47 .

[0036] The syringe body 41 has formed therein a plurality of (two in this example) paste storage chambers 49 and 49' filled with paste. The two paste storage chambers 49, 49' are lined up along the width direction Y inside the syringe body 41 and are formed to have the same shape. One end 41A of the syringe body 41 is formed with a circular wall portion 41a that has a circular shape when cut in the width direction Y that is perpendicular to the longitudinal direction X, and the other end 41B is formed with a finger hook portion 47.

[0037] The two protrusions 43, 43' are cylindrical portions that protrude in the longitudinal direction X from an end face of one end 41A (circular wall portion 41a) of the syringe body 41 and have respective tips that serve as outlets 51, 51'. The inner periphery of the protrusion 43 forms a part of the paste storage chamber 49, and the inner periphery of the protrusion 43' forms a part of the paste storage chamber 49'. The two protrusions 43, 43' are connected via an upright wall 41c that stands up from the circular wall portion 41a, and the inclination of the two protrusions 43, 43' is regulated.

[0038] The engaging portion 45 constitutes an engaging structure that fixes the mounting member M to the tip end portion of the syringe 3 (one end portion 41A of the syringe body 41), and is a portion that engages with the engaged portions (engaged portions 107 and 129) of the mounting member M (the static mixer 7 and the cap 11). In Example 1, the engaging portion 45 is composed of three protruding pieces 45A, 45B, and 45C formed on the outer circumferential surface of the circular wall portion 41a of the syringe body 41, as shown in FIG. 4C .

[0039] The protrusions 45A, 45B, and 45C are aligned along the rotation direction of the outer casing OM and are asymmetrical about the central axis CA, which is the center of rotation of the outer casing OM, when viewed along the central axis CA. Note that "point symmetry" generally refers to a shape that overlaps with the original shape when rotated 180° about the point of symmetry, but "asymmetrical" here refers to a shape that does not overlap with the original shape when the syringe 3 is rotated about the central axis CA, except when rotated 360°.

[0040] In the first embodiment, the protrusions 45A, 45B, and 45C are arranged at unequal intervals along the rotational direction of the outer casing OM. Here, the distance in the rotational direction from the protrusion 45A to the protrusion 45B is the same as the distance in the rotational direction from the protrusion 45A to the protrusion 45C. On the other hand, the distance in the rotational direction from the protrusion 45B to the protrusion 45C is shorter than the distance from the protrusion 45A to the protrusion 45B and the distance from the protrusion 45A to the protrusion 45C.

[0041] Furthermore, the protrusions 45A, 45B, and 45C have different shapes when viewed along the central axis CA. That is, the length of the protrusion 45A in the rotational direction is longer than the lengths of the protrusions 45B and 45C in the rotational direction. On the other hand, the lengths of the protrusions 45B and 45C in the rotational direction are the same, but the directions in which they protrude from the outer circumferential surface of the circular wall portion 41a are different.

[0042] The protrusions 45B and 45C are symmetrical with respect to an axis of symmetry AS that passes through the central axis CA and the circumferential center position of the protrusion 45A. An arrow AR1 indicating the position of the protrusion 45A is engraved on the surface of the circular wall portion 41a.

[0043] The finger hook 47 is a flange-shaped portion extending in the width direction Y and the thickness direction Z from the outer peripheral surface of the other end 41B of the syringe body 41. As shown in FIGS. 4C and 4D , the finger hook 47 of Example 1 has a substantially hexagonal outer peripheral shape. The finger hook 47 may be textured on at least a surface 47a on the side of one end 41A. Textured surface 47a prevents fingers from slipping during use and reduces the visibility of gate marks, improving the appearance.

[0044] As shown in FIG. 6, the outer circumferential surface of the syringe body 41 has a pair of widthwise outer circumferential surfaces 57, 57', a pair of thicknesswise outer circumferential surfaces 59, 59', and four connecting outer circumferential surfaces 61.

[0045] The pair of widthwise outer peripheral surfaces 57, 57' are surfaces of the outer peripheral surface of the syringe body 41 that are located on opposite sides along the thickness direction Z. Each of the widthwise outer peripheral surfaces 57, 57' has a flat portion 57A that is flat along the longitudinal direction X and the width direction Y. Each of the widthwise outer peripheral surfaces 57, 57' has a groove-like recessed portion 57B that extends in the longitudinal direction X and is recessed more than the flat portion 57A. The recessed portion 57B is located between two paste storage chambers 49, 49' formed inside the syringe body 41, and the flat portion 57A is divided into two by the recessed portion 57B along the width direction Y. Each recessed portion 57B has a wedge-shaped cross section whose length in the width direction Y gradually narrows as it becomes deeper.

[0046] The pair of thickness direction outer peripheral surfaces 59, 59' are surfaces of the outer peripheral surface of the syringe body 41 that are located on opposite sides along the width direction Y. The thickness direction outer peripheral surfaces 59, 59' are curved outward in the width direction Y with a predetermined radius of curvature, which is set to a curved surface of R5 in this example.

[0047] The connecting outer peripheral surface 61 is a surface of the outer peripheral surface of the syringe body 41 that is respectively set between the width direction outer peripheral surface 57 and the thickness direction outer peripheral surface 59, between the width direction outer peripheral surface 57' and the thickness direction outer peripheral surface 59, between the width direction outer peripheral surface 57 and the thickness direction outer peripheral surface 59', and between the width direction outer peripheral surface 57' and the thickness direction outer peripheral surface 59'. The connecting outer peripheral surface 61 is curved with a predetermined radius of curvature (e.g., radii of curvature R1 to R5, R1.5 in Example 1) and smoothly connects the width direction outer peripheral surface 57 and the thickness direction outer peripheral surface 59, the width direction outer peripheral surface 57' and the thickness direction outer peripheral surface 59, the width direction outer peripheral surface 57 and the thickness direction outer peripheral surface 59', and the width direction outer peripheral surface 57' and the thickness direction outer peripheral surface 59'. In Example 1, the connecting outer peripheral surface 61 and the pair of thickness direction outer peripheral surfaces 59, 59' are formed by combining multiple curved surfaces set to different radii of curvature. The connecting outer peripheral surface 61 and the pair of thickness direction outer peripheral surfaces 59, 59' may be formed by curved surfaces set to the same radius of curvature.

[0048] The paste storage chamber 49 has a discharge port 51 at one end 49A (protruding portion 43) that opens one end of the paste storage chamber 49 and through which paste pushed out by the plunger 5 is discharged, and a filling port 53 at the other end 49B that opens the other end of the paste storage chamber 49. The paste storage chamber 49 has a tapered shape at one end 49A that fits over the tip end of the plunger 5 (top portion 83 of the elastic holder 15) inserted into the paste storage chamber 49. In addition, a retaining projection 55 is provided on the inner peripheral surface of the other end 49B to prevent the plunger 5 inserted into the paste storage chamber 49 from falling out. Note that the paste storage chamber 49' has a similar configuration to the paste storage chamber 49, and therefore the same reference numerals as those of the paste storage chamber 49 are used and description thereof will be omitted.

[0049] 6, the cross section of the paste storage chamber 49 taken in a direction perpendicular to the longitudinal direction X has an elliptical shape in which the major axis direction LA is aligned with the thickness direction Z and the minor axis direction SA is aligned with the width direction Y. Note that the term "elliptical shape" is a concept that includes not only an elliptical shape defined geometrically, but also shapes that approximate an ellipse, such as an oval (a shape formed by connecting two semicircles with two straight lines), an elliptical arch shape (a shape formed by cutting out a portion of an ellipse along a straight line), an oblate ellipse (a shape formed by flattening an ellipse in the major axis or minor axis direction), and an oval shape. In Example 1, the inner peripheral surface of the paste storage chamber 49 is composed of a pair of inner flat surface portions 63, 63' that are flat along the longitudinal direction X and the thickness direction Z, and a pair of inner curved surface portions 65, 65' that are curved at a predetermined curvature.

[0050] The pair of inner flat surface portions 63, 63' face each other in the width direction Y, sandwiching the internal space of the paste storage chamber 49. The pair of inner curved surface portions 65, 65' face each other in the thickness direction Z, sandwiching the internal space of the paste storage chamber 49, and smoothly connect the pair of inner flat surface portions 63, 63'. As a result, in Example 1, the cross-sectional shape of the inner peripheral surface of the paste storage chamber 49 presents an oblate ellipse.

[0051] In Example 1, the length dimension T1 in the major axis direction LA of the elliptical shape of the inner peripheral surface of the paste storage chamber 49 is preferably in the range of 1.1 to 2.0, where the length dimension W1 in the minor axis direction SA is 1. In Example 1, the length dimension T1 in the major axis direction LA is set to 1.3, where the length dimension W1 in the minor axis direction SA is 1. Specifically, the length dimension T1 in the major axis direction LA is preferably 5 mm to 20 mm, and the length dimension W1 in the minor axis direction SA is preferably 4.5 mm to 10 mm.

[0052] [Plunger Body] Fig. 7A is a front view of the plunger body 13, Fig. 7B is a side view, Fig. 7C is a plan view, and Fig. 7D is a bottom view. Also, Fig. 8 is a cross-sectional view taken along line VIII-VIII shown in Fig. 7A.

[0053] The plunger body 13 includes a pressing portion 67 and two rod-shaped portions 69 and 69'.

[0054] The pressing portion 67 is a portion that a user presses with a finger (e.g., a thumb) when holding the syringe 3 between two fingers (e.g., an index finger and a middle finger) and placing the fingers on the finger hook 47 to push the plunger 5 into the syringe 3. As shown in Fig. 7D , the pressing portion 67 has an elliptical outer periphery that is elongated in the width direction Y, and has two rod-shaped portions 69, 69' disposed in the center. The bottom surface of the pressing portion 67 is curved in the direction in which the rod-shaped portions 69, 69' extend so that the user can easily press the pressing portion 67 with their fingers.

[0055] The rod-shaped portions 69, 69' are rod-shaped portions extending in parallel from the pressing portion 67 along the longitudinal direction X. In Example 1, the rod-shaped portions 69, 69' are lined up at a predetermined interval along the major axis direction (width direction Y) of the pressing portion 67, and are simultaneously inserted into the paste storage chambers 49, 49', respectively. Here, the rod-shaped portion 69 and the rod-shaped portion 69' have the same shape, and both can be inserted into both the paste storage chambers 49, 49'. In other words, when the rod-shaped portion 69 is inserted into the paste storage chamber 49, the rod-shaped portion 69' is inserted into the paste storage chamber 49', and when the rod-shaped portion 69 is inserted into the paste storage chamber 49', the rod-shaped portion 69' is inserted into the paste storage chamber 49.

[0056] 8, the cross section of the rod-shaped portion 69 in the width direction Y is formed in a cross shape composed of a combination of a thickness direction wall portion 71A extending in the thickness direction Z and a width direction wall portion 71B extending in the width direction Y. The length dimension in the thickness direction Z of the thickness direction wall portion 71A is greater than the length dimension in the width direction Y of the width direction wall portion 71B. When the rod-shaped portion 69 is inserted into the paste storage chamber 49 (49'), the tip of the thickness direction wall portion 71A is arranged along the inner curved surface portions 65, 65' of the paste storage chamber 49 (49'), and the tip of the width direction wall portion 71B is arranged along the inner flat surface portions 63, 63' of the paste storage chamber 49 (49').

[0057] One end of the width-direction wall portion 71B in the longitudinal direction X is formed with a pair of protrusions 73, 73 formed to protrude in the width direction Y, and a pair of cutouts 75, 75. As a result, when the rod-shaped portion 69 is inserted into the paste storage chamber 49 (49'), the pair of protrusions 73, 73 of the width-direction wall portion 71B come into contact with the inner flat surface portions 63, 63', and the portion of the width-direction wall portion 71B where the pair of cutouts 75, 75 are formed is bent. As a result, the rod-shaped portion 69 is positioned in the width direction Y, and rattle is prevented. Similarly, a plurality of protrusions 77 are formed on the thickness-direction wall portion 71A and the width-direction wall portion 71B to prevent rattle of the rod-shaped portion 69.

[0058] The rod-shaped portion 69 has a holder engagement portion 79 formed at its tip with which the elastic body holder 15 loosely engages. The holder engagement portion 79 includes a tip wall portion 79A that contacts the bottom surface 81A of the elastic body holder 15, and an engagement protrusion 79B that extends from the tip wall portion 79A in the longitudinal direction X and is inserted into an engagement hole 81B formed in the bottom surface 81A of the elastic body holder 15. As shown in FIG. 7C , the outer peripheral shape of the tip wall portion 79A is elliptical in shape to match the cross-sectional shape of the paste storage chamber 49 (49′). When the rod-shaped portion 69 is inserted into the paste storage chamber 49 (49′), if the protrusions 73, 73 and the protrusion 77 climb over the removal prevention protrusions 55 (55′), the removal prevention protrusions 55 (55′) catch on the protrusions 73, etc., preventing the plunger 5 from falling out.

[0059] The rod-shaped portion 69' has the same configuration as the rod-shaped portion 69, and therefore the reference numerals of the respective parts of the rod-shaped portion 69 are marked with "'" and the description thereof will be omitted.

[0060] [Elastic Body Holder] FIG. 9A is a perspective view of the elastic body holder 15, and FIG. 9B is a bottom view thereof.

[0061] The elastic holder 15 is loosely engaged with each of the holder engaging portions 79, 79' at the tip of the plunger body 13, constituting the tip of the plunger 5. The elastic holder 15 has a body portion 81, a top portion 83, and a neck portion 85. The body portion 81 has an elliptical cross section in the width direction Y. The bottom surface 81A of the body portion 81 has an engaged hole 81B into which the engaging protrusion 79B of the holder engaging portion 79 or the engaging protrusion 79B' of the holder engaging portion 79' is inserted. The outer peripheral surface 81C of the body portion 81 has an elliptical shape that follows the elliptical shape of the inner peripheral surface (inner flat surface portions 63, 63' and inner curved surface portions 65, 65') of the paste storage chamber 49 (49'). The top portion 83 has a shape that tapers toward the tip. The neck portion 85 is an elliptical portion formed between the body portion 81 and the top portion 83. The neck portion 85 and the body portion 81 and top portion 83 that face each other across the neck portion 85 form an annular groove portion 81D in which the O-ring 17 is attached.

[0062] The elliptical shape of the body portion 81 is smaller than the cross-sectional shape of the paste storage chamber 49 (49'), and has a cross-sectional shape similar to the cross-sectional shape of the paste storage chamber 49 (49'), and follows the elliptical shape of the inner peripheral surface of the paste storage chamber 49 (49'). Therefore, when the elastic holder 15 is inserted into the paste storage chamber 49 (49'), the distance from the outer peripheral surface 81C of the body portion 81 to the inner peripheral surface of the paste storage chamber 49 (49') is constant around the entire circumference of the body portion 81. Furthermore, in Example 1, similar to the paste storage chamber 49 (49'), the length dimension T2 in the major axis direction of the elliptical shape of the body portion 81 is preferably in the range of 1.1 to 2.0, where the length dimension W2 in the minor axis direction is 1. Specifically, in Example 1, the length dimension T2 in the major axis direction is set to 1.3, where the length dimension W2 in the minor axis direction is 1.

[0063] The elliptical shape of the neck portion 85 is smaller than the elliptical shape of the body portion 81 and has a cross-sectional shape similar to the elliptical shape of the body portion 81. In other words, the elliptical shape of the neck portion 85 has a cross-sectional shape similar to the cross-sectional shape of the paste storage chamber 49 (49'). Therefore, when the elastic body holder 15 is inserted into the paste storage chamber 49 (49'), the distance from the outer peripheral surface 85C of the neck portion 85 to the inner peripheral surface of the paste storage chamber 49 (49') is constant over the entire circumference of the neck portion 85. Furthermore, in Example 1, the ratio of the length dimension in the major axis direction to the length dimension in the minor axis direction of the elliptical shape of the neck portion 85 is set to the same ratio as the elliptical shape of the body portion 81.

[0064] FIG. 10 is a cross-sectional view of the elastic holder 15 with the O-ring 17 attached to the annular groove 81D, taken along the width direction Y perpendicular to the longitudinal direction X at the neck portion 85. Here, the O-ring 17 is annular, but the neck portion 85 is elliptical. Therefore, when the O-ring 17 is attached to the annular groove 81D, it is stretched in the major axis direction (thickness direction Z) and becomes elliptical. The length dimension T3 of the elliptical O-ring 17 in the major axis direction is greater than the length dimension T2 of the elliptical shape of the body portion 81. Furthermore, the length dimension W3 of the elliptical O-ring 17 in the minor axis direction is greater than the length dimension W2 of the elliptical shape of the body portion 81. Therefore, the O-ring 17 is fixed while protruding from the annular groove 81D.

[0065] Furthermore, a stronger tensile force acts on region a of the O-ring 17, which is stretched in the longitudinal direction (thickness direction Z), than on region b, which is not stretched in the longitudinal direction (thickness direction Z). As a result, as shown in FIG. 10 , the wire diameter ΔA of the O-ring 17 in region a is thinner than the wire diameter ΔB in region b, and the wire diameter of the O-ring 17 varies depending on the circumferential position. Note that the "wire diameter of the O-ring 17" refers to the cross-sectional thickness of the O-ring 17. Because the wire diameter of the O-ring 17 varies depending on the circumferential position, the amount of protrusion of the O-ring 17 from the annular groove 81D varies, and the thinner the wire diameter (e.g., region a), the less the O-ring 17 protrudes from the annular groove 81D.

[0066] Furthermore, the length T3 in the major axis direction of the elliptical O-ring 17 is slightly larger than the length T1 in the major axis direction of the elliptical shape of the inner peripheral surface of the paste storage chamber 49 or the paste storage chamber 49'. Also, the length W3 in the minor axis direction of the elliptical O-ring 17 is slightly larger than the length W1 in the minor axis direction of the elliptical shape of the inner peripheral surface of the paste storage chamber 49 or the paste storage chamber 49'. Therefore, when the elastic body holder 15 is inserted into the paste storage chamber 49 (49') of the syringe 3, the O-ring 17 comes into contact with the inner peripheral surface of the paste storage chamber 49 (49') and is compressed between the inner peripheral surface of the paste storage chamber 49 (49') and the outer peripheral surface 85C of the neck portion 85.

[0067] 11 shows a cross-sectional view (schematic diagram) of the elastic holder 15 with the O-ring 17 attached to the annular groove 81D inserted into the paste storage chamber 49 of the syringe 3, cut at the neck portion 85 in the width direction Y perpendicular to the longitudinal direction X, and cross-sectional views (schematic diagrams) of the elastic holder 15 as viewed from the front and side. In Fig. 11, the part of the O-ring 17 that protrudes from the annular groove 81D and is compressed when inserted into the paste storage chamber 49 is shown in gray, and the state of the O-ring 17 before compression is shown by a dashed line.

[0068] 11, when the plunger 5 is inserted into the syringe 3 with the O-ring 17 attached to the annular groove 81D, the O-ring 17 is sandwiched and compressed between the inner circumferential surface (inner flat surface portions 63, 63' and inner curved surface portions 65, 65') of the paste storage chamber 49 and the outer circumferential surface 85C of the neck portion 85. Here, the wire diameter of the O-ring 17 varies depending on the circumferential position, and the thinner the wire diameter, the less the amount of protrusion from the annular groove 81D.

[0069] 11 , the magnitude of the difference (ΔX1, ΔX2) between the distance Gd from the outer peripheral surface 85C of the neck portion 85 to the inner peripheral surface of the paste storage chamber 49 and the wire diameter Wr of the O-ring 17 varies depending on the circumferential position of the O-ring 17. Therefore, the compression rate of the O-ring 17 when inserted into the paste storage chamber 49 varies depending on the circumferential position.

[0070] That is, in the elliptical O-ring 17, the region b with a thick wire diameter protrudes more from the annular groove portion 81D than the region a with a thin wire diameter, and the difference ΔX2 in the region b is larger than the difference ΔX1 in the region a. Therefore, when the O-ring 17 is inserted into the syringe 3, the region b of the O-ring 17 is pressed more toward the inside of the paste storage chamber 49 than the region a, and the compression rate in the region b is larger than the compression rate in the region a. As a result, the compression rate in the major axis direction (thickness direction Z) of the elliptical O-ring 17 is larger than the compression rate in the minor axis direction (width direction Y) of the O-ring 17.

[0071] Furthermore, since the compression rate of the O-ring 17 varies depending on the circumferential position, the frictional force generated between the O-ring 17 and the inner peripheral surface of the paste storage chamber 49 (49') varies depending on the circumferential position of the O-ring 17. That is, the frictional force between the apex 17A of the O-ring 17 in the major axis direction, which is stretched into an elliptically shape, and the inner peripheral surface of the paste storage chamber 49 (49') is greater than the frictional force between the apex 17B of the O-ring 17 in the minor axis direction, which is stretched into an elliptically shape, and the inner peripheral surface of the paste storage chamber 49 (49'). Therefore, by adjusting the major axis dimensions of the elliptical cross-sectional shape of the paste storage chamber 49 (49') and the elliptical cross-sectional shape of the plunger 5 relative to the minor axis dimensions, it is easy to adjust the ease of movement of the plunger 5 in the longitudinal direction while maintaining the seal between the inner peripheral surface of the paste storage chamber 49 (49') and the elastic body (O-ring 17).

[0072] Furthermore, it is preferable that the compression ratio of the O-ring 17 in the major axis direction (compression ratio in region b) is approximately 10 to 14%, and the compression ratio in the minor axis direction (compression ratio in region a) is approximately 3 to 7%. Specifically, in Example 1, the compression ratio in the major axis direction is 12%, and the compression ratio in the minor axis direction is 5%. The compression ratio C (%) is calculated by the following formula: C = (Wr - Gd) / Wr x 100, where Wr: wire diameter of the elastic body (O-ring) [mm], and Gd: distance from the outer peripheral surface of the neck portion to the inner peripheral surface of the paste storage chamber [mm].

[0073] The elastic body holder 15 is loosely engaged with the holder engaging portion 79 (79') at the tip of the plunger body 13. Therefore, when the elastic body holder 15, with the O-ring 17 attached, is inserted into the paste storage chamber 49 (49') of the syringe 3 together with the plunger body 13, the plunger body 13 is pushed in, and the elastic body holder 15 moves together with the plunger body 13 in the longitudinal direction X within the paste storage chamber 49 (49'). On the other hand, when the plunger body 13 is pulled back, the elastic body holder 15 is separated from the plunger body 13 and is left behind in the paste storage chamber 49 (49'). This prevents air from being drawn into the paste storage chamber 49 (49') through the discharge ports 51, (51') even if the plunger 5 is accidentally pulled back.

[0074] [Static Mixer] (Mixing Chip Main Body) Fig. 12A is a perspective view of the mixing chip main body 19, and Fig. 12B is a bottom view. Fig. 13 is a cross-sectional view taken along line XIII-XIII shown in Fig. 12B.

[0075] The mixing tip main body 19 is a member that, in combination with the mixer housing 21, constitutes the inner member IM of the static mixer 7, which is the mounting member M. The mixing tip main body 19 includes a base 87, two insertion portions 89, 89', a pair of rotational engagement pieces 91, 91', a backflow prevention wall 35, and an element group 39.

[0076] The base 87 is a cylindrical portion that fits inside the mixer exterior body 23, which is the exterior body OM. A flange portion 87C extending radially outward is formed on the outer periphery of the base 87. The flange portion 87C fits into a groove (circumferential groove 103) formed on the inner circumferential surface of the mixer exterior body 23, which will be described later, and the mixing tip main body 19 is fixed to the mixer exterior body 23 in a state that allows relative rotation about the central axis CA.

[0077] The two insertion portions 89, 89' and the pair of rotary engagement pieces 91, 91' are formed on a first end surface 87A of the base 87 facing the syringe 3, and extend from the first end surface 87A in the longitudinal direction X. When the static mixer 7 is attached to the syringe 3, the two insertion portions 89, 89' are inserted into the two protrusions 43, 43' of the syringe 3, respectively. A paste passage 29 is formed inside the insertion portion 89, and a paste passage 29' is formed inside the insertion portion 89'. The pair of rotary engagement pieces 91, 91' are portions that respectively engage with engagement grooves (a pair of first engagement grooves 105A, 105A' or a pair of second engagement grooves 105B, 105B') of the mixer exterior body 23, which will be described later.

[0078] The backflow prevention wall 35 extends along the central axis CA from the center of the second end face 87B opposite the first end face 87A of the base 87. The tip of the backflow prevention wall 35 is the paste joining position JP, and the element group 39 extends from the tip of the backflow prevention wall 35. The element group 39 is made up of a plurality of elements (eight in Example 1) lined up along the central axis CA.

[0079] The paste passage 29 is formed continuously penetrating the insertion portion 89 and the base portion 87. The inlet hole 29A is formed in the end face of the insertion portion 89, and the outlet hole 29B is formed in the second end face 87B of the base portion 87. Similarly, the paste passage 29' is formed continuously penetrating the insertion portion 89' and the base portion 87. The inlet hole 29A' is formed in the end face of the insertion portion 89', and the outlet hole 29B' is formed in the second end face 87B of the base portion 87.

[0080] (Mixer Housing) Fig. 14A is a perspective view of the mixer housing 21, Fig. 14B is a bottom view, and Fig. 15 is a cross-sectional view taken along line XV-XV shown in Fig. 14B.

[0081] The mixer housing 21 is a member that, in combination with the mixing tip main body 19, constitutes the inner member IM of the static mixer 7, which is the mounting member M. The mixer housing 21 includes a base housing portion 93 and an element housing portion 37.

[0082] The base housing portion 93 includes a circular end wall portion 93A that covers the second end face 87B of the base 87 of the mixing tip main body portion 19 when the mixer housing 21 is placed over the mixing tip main body portion 19, and a peripheral wall portion 93B that rises from the edge of the end wall portion 93A, surrounds the base 87, and extends until its tip contacts the flange portion 87C.

[0083] A recess 93C is provided on the inner wall of the end wall portion 93A at a position opposite the outlet holes 29B, 29B'. By fitting the mixer housing 21 onto the mixing tip body 19, an intermediate passage 31 is formed inside the inner member IM, which is partitioned by the base 87, the backflow prevention wall 35, and the recess 93C (see FIG. 3).

[0084] The element housing portion 37 is a cylindrical portion with an open tip that extends in the longitudinal direction X from a through-hole formed in the center of the end wall portion 93A of the base housing portion 93. When the mixer housing 21 is placed over the mixing tip body 19, the element group 39 is inserted into the element housing portion 37 to form the mixing passage 33. A guide tip engagement groove 37A for fixing the guide tip 9 is formed on the outer periphery of the element housing portion 37.

[0085] (Mixer exterior body) Fig. 16A is a front view of the mixer exterior body 23, Fig. 16B is a plan view, and Fig. 16C is a bottom view. Also, Fig. 17 is a cross-sectional view taken along line XVII-XVII shown in Fig. 16B, and Fig. 18 is a cross-sectional view taken along line XVIII-XVIII shown in Fig. 16A.

[0086] The mixer exterior 23 is a cylindrical member that constitutes the exterior OM of the static mixer 7, which is the mounting member M. The static mixer 7, which is the mounting member M, is configured by accommodating an inner member IM, which is made up of the mixing tip main body 19 and the mixer housing 21, inside the mixer exterior 23. The mixer exterior 23 also rotates relatively to the syringe 3 around a central axis CA.

[0087] The mixer exterior 23 includes a top wall 95 having a regular hexagonal outer periphery, a first peripheral wall 97 rising from the edge of the top wall 95, and a second peripheral wall 99 extending continuously from the first peripheral wall 97 via a step. The interior of the mixer exterior 23 defines a first space S1 surrounded by the top wall 95 and the first peripheral wall 97, and a second space S2 surrounded by the second peripheral wall 99 (see FIG. 17 ). An inner member IM, consisting of a mixing tip main body 19 and a mixer housing 21, fits into the first space S1 in a manner that allows it to rotate around a central axis CA. The tip of the syringe 3 (one end 41A of the syringe body 41) is inserted into the second space S2 with the inner member IM housed therein (see FIG. 3 ).

[0088] The top wall 95 covers the end wall 93A of the mixer housing 21 and faces the opening through which the syringe 3 is inserted (see FIG. 3). A top penetration tube 101 is formed in the center of the top wall 95 to expose the element housing 37 to the outside. The top penetration tube 101 is a cylindrical portion that protrudes from the top wall 95 and penetrates the top wall 95. When the inner member IM consisting of the mixing tip main body 19 and the mixer housing 21 is housed in the mixer exterior body 23, the element housing 37 penetrates the top penetration tube 101. In addition, an arrow AR2 indicating the position of a recess 107A (described later) is engraved on the surface of the top wall 95 (see FIG. 16B).

[0089] As shown in Fig. 16B, the outer peripheral surface of the first circumferential wall portion 97 has a regular hexagonal shape when viewed along the central axis CA. As shown in Fig. 16C, the inner peripheral surface of the first circumferential wall portion 97 has a circular shape when viewed along the central axis CA. The inner peripheral surface of the first circumferential wall portion 97 is formed with a circumferential groove 103, a pair of first engaged grooves 105A, 105A', and a pair of second engaged grooves 105B, 105B'.

[0090] As shown in FIG. 3, the circumferential groove 103 is a recess into which the flange portion 87C of the mixing tip body 19 fits, and extends in the circumferential direction (the rotation direction of the inner member IM).

[0091] The first engaged groove 105A and the second engaged groove 105B on one side are recesses with which one of the rotary engaging pieces 91 engages. The first engaged groove 105A' and the second engaged groove 105B' on the other side are recesses with which the other of the rotary engaging pieces 91' engages. The pair of first engaged grooves 105A, 105A' and the pair of second engaged grooves 105B, 105B' are arranged side by side in the circumferential direction (the direction of rotation of the inner member IM) at a predetermined interval. Here, the pair of first engaged grooves 105A, 105A' are formed in positions facing each other in the thickness direction Z across the central axis CA. The pair of second engaged grooves 105B, 105B' are formed in positions facing each other in a direction offset in the circumferential direction from the thickness direction Z across the central axis CA.

[0092] When assembled into the static mixer 7, the mixing tip main body 19 and the mixer housing 21 rotate relative to the mixer exterior body 23 around the central axis CA. At this time, depending on the positional relationship in the rotational direction between the mixing tip main body 19 and the mixer housing 21 and the mixer exterior body 23, one rotational engagement piece 91 engages with either the first engaged groove 105A or the second engaged groove 105B, and the other rotational engagement piece 91' engages with either the first engaged groove 105A' or the second engaged groove 105B'. This determines the relative rotational position of the mixing tip main body 19 and the mixer housing 21 and the mixer exterior body 23.

[0093] As shown in FIG. 16B , the outer peripheral surface of the second peripheral wall portion 99 has a hexagonal shape when viewed along the central axis CA. The outer peripheral surface of the second peripheral wall portion 99 has a pair of long sides 99A, 99A located on opposite sides of each other along the thickness direction Z. The pair of long sides 99A, 99A bulge radially outward to allow insertion of the circular wall portion 41a of the syringe 3 (see FIGS. 16B and 16C ). The inner peripheral surface of the second peripheral wall portion 99 has a circular shape when viewed along the central axis CA, as shown in FIG. 16C .

[0094] The inner circumferential surface of the second circumferential wall portion 99 is formed with a stepped portion 98 and an engaged portion 107 composed of three recesses 107A, 107B, and 107C. The stepped portion 98 is formed at the boundary between the first circumferential wall portion 97 and the second circumferential wall portion 99, and is a stepped unevenness that narrows the inner diameter of the mixer exterior body 23 toward the top wall portion 95, and extends in the circumferential direction (the direction of rotation of the inner member IM). The circular wall portion 41a of the syringe 3 abuts against the stepped portion 98 when the static mixer 7 is attached to the tip of the syringe 3 (see FIG. 3 ).

[0095] In addition, the engaged portion 107 forms an engagement structure that fixes the mounting member M to the tip portion of the syringe 3 (one end portion 41A of the syringe body 41), and is the part that engages with the engaging portion 45 (three protrusion pieces 45A, 45B, 45C) of the syringe 3.

[0096] The recesses 107A, 107B, and 107C have first grooves 107Aa, 107Ba, and 107Ca, respectively, and second grooves 107Ab, 107Bb, and 107Cb. The first grooves 107Aa, 107Ba, and 107Ca open to an end face 99B of the second circumferential wall 99 (the opening of the mixer exterior body 23 into which the syringe 3 is inserted) and extend along the longitudinal direction X (center axis CA) to the step portion 98. The second grooves 107Ab, 107Bb, and 107Cb extend from the ends of the first grooves 107Aa, 107Ba, and 107Ca along the step portion 98 in the rotational direction of the mixer exterior body 23. Window portions 109A, 109B, and 109C are formed at positions corresponding to the second groove portions 107Ab, 107Bb, and 107Cb, respectively, penetrating the second peripheral wall portion 99. In other words, the second groove portions 107Ab, 107Bb, and 107Cb are formed by the edges of the window portions 109A, 109B, and 109C.

[0097] The recesses 107A, 107B, and 107C are aligned along the rotational direction of the mixer exterior body 23 and, when viewed along the central axis CA, are asymmetrical about the central axis CA, which is the center of rotation of the mixer exterior body 23. In Example 1, the recesses 107A, 107B, and 107C are aligned at unequal intervals along the rotational direction of the mixer exterior body 23. That is, the recess 107A is formed on the inner circumferential surface of the second circumferential wall portion 99 at a position corresponding to a corner of the outer circumferential surface of the second circumferential wall portion 99. The recesses 107B and 107C are formed on the inner circumferential surface of the second circumferential wall portion 99 at positions corresponding to flat portions of the outer circumferential surface of the second circumferential wall portion 99 (see FIGS. 16C and 18 ). Furthermore, recess 107A has a shape into which protrusion 45A, which is engaging portion 45, can be inserted, recess 107B has a shape into which protrusion 45B, which is engaging portion 45, can be inserted, and recess 107C has a shape into which protrusion 45C, which is engaging portion 45, can be inserted. Recesses 107A, 107B, and 107C have different shapes from one another when viewed along central axis CA.

[0098] [Cap] The cap 11 is fixed to the tip of the syringe 3 (one end 41A of the syringe body 41) in place of the static mixer 7 during storage or transportation of the paste injector 1. Components that are common to the static mixer 7 are given the same component names, and descriptions thereof may be omitted.

[0099] (Cap Inner Member) Fig. 19A is a perspective view of the cap inner member 25, and Fig. 19B is a bottom view thereof. Also, Fig. 20 is a cross-sectional view taken along line XX-XX shown in Fig. 19B.

[0100] The cap inner member 25 is a member that constitutes the inner member IM of the cap 11 that is the mounting member M, and is a member that corresponds to the mixing tip main body 19 and mixer housing 21 that are the inner member IM of the static mixer 7.

[0101] The cap inner member 25, like the mixing tip main body 19, includes a base 111, two insertion portions 113, 113', and a pair of rotational engagement pieces 115, 115'.

[0102] The base 111 is a cylindrical portion that fits inside the cap outer body 27, which is the outer body OM. A flange portion 117C that extends radially outward is formed on the outer periphery of the base 111. The flange portion 117C fits into a groove (circumferential groove 125) formed on the inner circumferential surface of the cap outer body 27, which will be described later, and the cap inner member 25 is fixed to the cap outer body 27 in a state that allows relative rotation about the central axis CA.

[0103] The two insertion portions 113, 113' and the pair of rotational engagement pieces 115, 115' are formed on a first end surface 111A of the base 111 that faces the syringe 3, and extend from the first end surface 111A in the longitudinal direction X. When the cap 11 is attached to the syringe 3, the two insertion portions 113, 113' are inserted into the two protrusions 43, 43' of the syringe 3, respectively. Unlike the case of the mixing tip main body 19, the insertion portions 113, 113' have a columnar shape for sealing the outlets 51, 51' of the syringe 3, and no passage is formed therein. The pair of rotational engagement pieces 115, 115' are portions that respectively engage with engagement grooves (a pair of first engagement grooves 127A, 127A' or a pair of second engagement grooves 127B, 127B') of the cap exterior body 27, which will be described later.

[0104] A pair of bottomed recesses 117, 117 are formed on a second end surface 111B of the base portion 111 opposite to the first end surface 111A.

[0105] (Cap exterior body) Fig. 21A is a front view of the cap exterior body 27, Fig. 21B is a plan view, and Fig. 21C is a bottom view. Also, Fig. 22 is a cross-sectional view taken along line XXII-XXII shown in Fig. 21B, and Fig. 23 is a cross-sectional view taken along line XXIII-XXIII shown in Fig. 21A.

[0106] The cap exterior body 27 is a cylindrical member that constitutes the exterior body OM of the cap 11, which is the mounting member M, and is a member that corresponds to the mixer exterior body 23, which is the exterior body OM of the static mixer 7. The cap 11, which is the mounting member M, is formed by storing the cap inner member 25 inside the cap exterior body 27. In addition, the cap exterior body 27 rotates relatively to the syringe 3 about the central axis CA.

[0107] The cap exterior body 27 includes a top wall portion 119 having a regular hexagonal outer periphery, a first peripheral wall portion 121 rising from the edge of the top wall portion 119, and a second peripheral wall portion 123 extending continuously from the first peripheral wall portion 121 via a step. The interior of the cap exterior body 27 defines a first space S1 surrounded by the top wall portion 119 and the first peripheral wall portion 121, and a second space S2 surrounded by the second peripheral wall portion 123 (see FIG. 22 ). An inner member IM, which is made up of the cap inner member 25, fits into the first space S1 in a manner that allows it to rotate around a central axis CA. With the inner member IM housed within the second space S2, the tip end portion (one end portion 41A of the syringe body 41) a of the syringe 3 is inserted.

[0108] The top wall 119 is a portion that closes the first space S1. Unlike the mixing tip main body 19, the top wall 119 is made of a curved plate member and does not have a top through-cylinder formed in the center. In addition, an arrow AR2 indicating the position of a recess 129A (described later) is engraved on the surface of the top wall 119 (see FIG. 21B).

[0109] When viewed along the central axis CA, the outer peripheral surface of the first circumferential wall portion 121 has a regular hexagonal shape as shown in Fig. 21B. When viewed along the central axis CA, the inner peripheral surface of the first circumferential wall portion 121 has a circular shape as shown in Fig. 21C. The inner peripheral surface of the first circumferential wall portion 121 is formed with a circumferential groove 125, a pair of first engaged grooves 127A, 127A', and a pair of second engaged grooves 127B, 127B'.

[0110] The circumferential groove 125 is a recess into which the flange portion 117C of the cap inner member 25 fits, and extends in the circumferential direction (the rotation direction of the cap inner member 25).

[0111] The first engaged groove 127A and the second engaged groove 127B on one side are recesses with which one of the rotary engaging pieces 115 engages. The first engaged groove 127A' and the second engaged groove 127B' on the other side are recesses with which the other of the rotary engaging pieces 115' engages. The pair of first engaged grooves 127A, 127A' and the pair of second engaged grooves 127B, 127B' are arranged side by side in the circumferential direction (the rotational direction of the cap inner member 25) at a predetermined interval. Here, the pair of first engaged grooves 127A, 127A' are formed at positions facing each other in the thickness direction Z across the central axis CA. The pair of second engaged grooves 127B, 127B' are formed at positions facing each other in a direction offset in the circumferential direction from the thickness direction Z across the central axis CA.

[0112] When assembled into the cap 11, the cap inner member 25 rotates relative to the cap outer body 27 about the central axis CA. At this time, one rotational engagement piece 115 engages with either the first engaged groove 127A or the second engaged groove 127B, and the other rotational engagement piece 115' engages with either the first engaged groove 127A' or the second engaged groove 127B', depending on the positional relationship in the rotational direction between the cap inner member 25 and the cap outer body 27. This determines the relative rotational positions of the cap inner member 25 and the cap outer body 27.

[0113] As shown in FIG. 21B , the outer peripheral surface of the second peripheral wall portion 123 has a hexagonal shape when viewed along the central axis CA. The outer peripheral surface of the second peripheral wall portion 123 has a pair of long sides 123A, 123A located on opposite sides of each other along the thickness direction Z. The pair of long sides 123A, 123A bulge radially outward to allow insertion of the circular wall portion 41a of the syringe 3 (see FIGS. 21B and 21C ). The inner peripheral surface of the second peripheral wall portion 123 has a circular shape when viewed along the central axis CA, as shown in FIG. 21C .

[0114] The inner circumferential surface of second circumferential wall portion 123 is formed with a stepped portion 120 and an engaged portion 129 composed of three recesses 129A, 129B, and 129C. Step portion 120 is formed at the boundary between first circumferential wall portion 121 and second circumferential wall portion 123, and is a stepped unevenness that narrows the inner diameter of cap exterior body 27 toward top wall portion 119, and extends in the circumferential direction (the direction of rotation of inner member IM). Step portion 120 is against which circular wall portion 41a of syringe 3 abuts when cap 11 is attached to the tip of syringe 3.

[0115] In addition, the engaged portion 129 forms an engagement structure that fixes the mounting member M to the tip portion of the syringe 3 (one end portion 41A of the syringe body 41), and is the part that engages with the engagement portion 45 (three protrusion pieces 45A, 45B, 45C) of the syringe 3.

[0116] The recesses 129A, 129B, and 129C have first grooves 129Aa, 129Ba, and 129Ca, respectively, and second grooves 129Ab, 129Bb, and 129Cb. The first grooves 129Aa, 129Ba, and 129Ca open to the end face of the second circumferential wall 123 (the opening of the cap exterior body 27 into which the syringe 3 is inserted) and extend along the longitudinal direction X (central axis CA) to the step portion 120. The second grooves 129Ab, 129Bb, and 129Cb extend from the ends of the first grooves 129Aa, 129Ba, and 129Ca along the step portion 120 in the rotational direction of the cap exterior body 27. Window portions 131A, 131B, and 131C are formed at positions corresponding to the second groove portions 129Ab, 129Bb, and 129Cb, respectively, penetrating the second peripheral wall portion 123. In other words, the second groove portions 129Ab, 129Bb, and 129Cb are defined by the edges of the window portions 131A, 131B, and 131C.

[0117] Furthermore, the recesses 129A, 129B, and 129C are aligned along the rotational direction of the cap exterior body 27 and, when viewed along the central axis CA, are asymmetrical about the central axis CA, which is the center of rotation of the cap exterior body 27. In Example 1, the recesses 129A, 129B, and 129C are aligned at unequal intervals along the rotational direction of the cap exterior body 27. That is, the recess 129A is formed on the inner circumferential surface of the second circumferential wall portion 123 at a position corresponding to a corner of the outer circumferential surface of the second circumferential wall portion 123. The recesses 129B and 129C are formed on the inner circumferential surface of the second circumferential wall portion 123 at positions corresponding to flat portions of the outer circumferential surface of the second circumferential wall portion 123 (see FIGS. 21C and 23 ). Furthermore, recess 129A has a shape into which protrusion 45A, which is engaging portion 45, can be inserted, recess 129B has a shape into which protrusion 45B, which is engaging portion 45, can be inserted, and recess 129C has a shape into which protrusion 45C, which is engaging portion 45, can be inserted. Recesses 129A, 129B, and 129C have different shapes when viewed along central axis CA.

[0118] 24 and 25 , the details of the process up to fixing the mounting member M to the syringe 3 will be described using the static mixer 7 as an example. Fig. 24 is a diagram showing the state prior to the static mixer 7 being placed over and fixed to the syringe 3. Fig. 24 shows the bottom surface of the static mixer 7, and the syringe 3 is shown in plan view with the finger hook 47 omitted. In Figs. 24 and 25 , the inner member IM is shown colored gray.

[0119] 24 , before being fixed to the syringe 3, the static mixer 7 is in a state in which one rotary engagement piece 91 is engaged with one second engagement groove 105B, and the other rotary engagement piece 91' is engaged with the other second engagement groove 105B'. In other words, the width direction Y of the mixer exterior body 23 does not coincide with the width direction Y of the inner member IM. In this state, the circular wall portion 41a of the syringe 3 can be inserted into the second space S2 surrounded by the second peripheral wall portion 99 of the mixer exterior body 23 only when the first groove portions 107Aa, 107Ba, and 107Ca of the recesses 107A, 107B, and 107C are positioned opposite the three protrusion pieces 45A, 45B, and 45C of the syringe 3, respectively. Only at this time does the protruding portion 43 of the syringe 3 face the insertion portion 89 of the mixing chip body 19 , and the protruding portion 43 ′ of the syringe 3 face the insertion portion 89 ′ of the mixing chip body 19 .

[0120] The user can align the protrusion 45A with the recess 107A by aligning the arrow AR1 on the surface of the circular wall 41a with the arrow AR2 on the surface of the top wall 95. As a result, the first groove 107Aa of the recess 107A faces the protrusion 45A, the first groove 107Ba of the recess 107B faces the protrusion 45B, the first groove 107Ca of the recess 107C faces the protrusion 45C, the insertion portion 89 faces the protrusion 43, and the insertion portion 89' faces the protrusion 43'.

[0121] When the circular wall portion 41a of the syringe 3 is inserted into the second space S2, the insertion portion 89 is inserted into the protrusion 43, and the insertion portion 89' is inserted into the protrusion 43'. As a result, the rotational position of the inner member IM (the mixing tip main body 19 and the mixer housing 21) is fixed relative to the syringe 3. The protrusion 45A is inserted into the first groove 107Aa of the recess 107A and abuts against the step 98. The protrusion 45B is inserted into the first groove 107Ba of the recess 107B and abuts against the step 98. The protrusion 45C is inserted into the first groove 107Ca of the recess 107C and abuts against the step 98.

[0122] Then, when the mixer outer casing 23 rotates around the central axis CA in this state, the inner member IM (the mixing tip main body 19 and the mixer housing 21) does not rotate, and only the mixer outer casing 23, which is the outer casing OM, rotates, resulting in the state shown in Figure 25.

[0123] 25 is a bottom view of the static mixer 7 after only the mixer exterior body 23 has rotated (the inserted syringe 3 is not shown). When only the mixer exterior body 23 rotates, one rotational engagement piece 91 engages with one of the first engagement grooves 105A, and the other rotational engagement piece 91' engages with the other first engagement groove 105A'. Furthermore, the protrusion 45A moves from the end of the first groove 107Aa along the step 98 into the second groove 107Ab and is exposed to the outside through the window 109A. Furthermore, the protrusion 45B moves from the end of the first groove 107Ba along the step 98 into the second groove 107Bb and is exposed to the outside through the window 109B. The protruding piece 45C extends from the end of the first groove 107Ca along the step 98 into the second groove 107Cb and is exposed to the outside through the window 109C.

[0124] As a result, the protruding pieces 45A, 45B, and 45C are engaged with the recesses 107A, 107B, and 107C, respectively, and the static mixer 7 and the syringe 3 are fixed to each other.

[0125] <Functions of Static Mixer and Paste Injector> The functions of the static mixer and paste injector of Example 1 will be described below.

[0126] The static mixer 7 of Example 1 has inlet holes 29A, 29A' and outlet holes 29B, 29B' for the paste stored in the syringe 3, and has a plurality of paste passages 29, 29' through which the paste passes, an intermediate passage 31 that guides the paste discharged from the outlet holes of the paste passages to a joining position JP, and a mixing passage 33 through which the plurality of types of paste that have joined at the joining position JP pass while being mixed.

[0127] The mixing passage 33 extends about a central axis CA that extends in the longitudinal direction X, and the multiple paste passages 29, 29' are arranged side by side on a circle centered on the central axis CA and extend in the longitudinal direction X. The inner circumferential surface of each of the multiple paste passages 29, 29' has a tapered portion on a distal surface 29C, 29C' that is away from the central axis CA, which is formed in a tapered shape that gradually approaches the central axis CA as it moves from the inflow holes 29A, 29A' to the outflow holes 29B, 29B', and the opening area of ​​the inflow holes 29A, 29A' is larger than the opening area of ​​the outflow holes 29B, 29B'.

[0128] This prevents air bubbles from forming in the paste flow path and prevents air bubbles from getting mixed into the dental material. Also, the opening area of ​​the inlet holes 29A, 29A' is larger than the opening area of ​​the outlet holes 29B, 29B', and the paste flow path is shaped to narrow as it moves from the inlet holes 29A, 29A' to the outlet holes 29B, 29B', making it easy to adjust the amount of dental material being dispensed by the force with which the plunger 5 is pressed.

[0129] Moreover, in Example 1, the tapered portions of the distal surfaces 29C, 29C' of the paste passages 29, 29' extend from the inlet holes 29A, 29A' to the outlet holes 29B, 29B', making the distal surfaces 29C, 29C' smooth and flat, further suppressing the formation of air bubbles.

[0130] Furthermore, in order to prevent air bubbles from being mixed into the dental material and to make it easier to adjust the amount of dental material to be dispensed by the force of pressing the plunger 5, the proximal surfaces 29D, 29D' of the inner circumferential surfaces of the paste passages 29, 29' that are close to the central axis CA may extend along the central axis CA. Furthermore, the centers of the outlet holes 29B, 29B' may be closer to the central axis CA than the centers of the inlet holes 29A, 29A'.

[0131] The intermediate passage 31 may be provided with a backflow prevention wall 35 that constitutes part of the intermediate passage 31 and prevents the paste coming out of the outlet hole 29B (29B') from flowing into other outlet holes 29B' (29B). The backflow prevention wall 35 may also be formed with curved surfaces 35A, 35A' at its base that direct the paste toward the joining position JP, and may extend along the central axis CA to the joining position JP. This configuration prevents the paste coming out of the outlet hole 29B (29B') from flowing into other outlet holes 29B' (29B), while also preventing air bubbles from being mixed into the dental material.

[0132] The paste injector 1 equipped with the static mixer 7 of Example 1 is capable of adjusting the plunger pushing force while preventing air bubbles from being mixed into the dental material being discharged.

[0133] Furthermore, the static mixer 7 of Example 1 is used to mix multiple types of pastes to prepare a dental material and then inject the dental material, so the static mixer 7 of Example 1 can inject the dental material into a desired location while properly preparing it.

[0134] (Example 2) <Overall configuration> Fig. 26 is an exploded perspective view of a paste injector of Example 2. Fig. 27 is a cross-sectional view of a static mixer fixed to the tip of a syringe of Example 2, cut in the width direction at a position passing through a central axis extending in the longitudinal direction. Note that, also in Example 2, the longitudinal direction (X), width direction (Y), and thickness direction (Z) are defined for paste injector 1001, as shown in Fig. 26 .

[0135] The paste injector 1001 of Example 2 includes a syringe 1003, a plunger 1005, a static mixer 1007, and a guide tip 1009, similar to Example 1. The guide tip 1009 is attached to the static mixer 1007 as needed, similar to Example 1, and the paste injector 1001 can be used even if the guide tip 1009 is not attached to the static mixer 1007.

[0136] 26 can be fixed to the tip end portion of the syringe 1003 (one end portion 1041A of the syringe body 1041) instead of the static mixer 1007. In Example 2 as well, the static mixer 1007 and the cap 1011 detachably attached to the tip end portion of the syringe 1003 (one end portion 1041A of the syringe body 1041) are collectively referred to as an attachment member M.

[0137] In addition, the plunger 1005 of Example 2 is composed of a plunger body 1013, an elastic body holder 1015 that loosely engages with the tip of the plunger body 1013, and a circular O-ring (elastic body) 1017 attached to the elastic body holder 1015, as in Example 1.

[0138] In Example 2, the shapes of the syringe 1003, static mixer 1007, and cap 1011 are different from those in Example 1. Each of these will be described in detail below.

[0139] [Syringe] Figure 28A is a perspective view of the tip of syringe 1003, and Figure 28B is a plan view. Figure 28C is a cross-sectional view of the main part taken along line XXVIII-XXVIII shown in Figure 28B. Portions common to those in Example 1 are assigned reference numerals obtained by adding 1000 to the reference numerals assigned to Figures 4A to 4D and 5, and descriptions thereof will be omitted.

[0140] In syringe 1003 of Example 2, similarly to Example 1, circular wall portion 1041a is formed at one end 1041A of syringe body 1041, and finger hook portion 1047 is formed at the other end 1041B of syringe body 1041. In addition, a pair of protrusions 1043, 1043' are formed to protrude from circular wall portion 1041a, and engaging portion 1045 consisting of three protrusions 1045A, 1045B, 1045C is formed on the outer circumferential surface of circular wall portion 1041a.

[0141] In Example 2, a recess 1041b is formed on the surface (end surface of one end 1041A) of the circular wall portion 1041a. The recess 1041b is formed between the peripheral edge of the circular wall portion 1041a and the protruding portions 1043, 1043', and an appropriate step is provided. The formation of the recess 1041b on the surface of the circular wall portion 1041a prevents the occurrence of sink marks when the syringe 1003 is molded from resin. Furthermore, preventing the occurrence of sink marks can suppress tilting of the protruding portions 1043, 1043'.

[0142] Also in the second embodiment, the surface of the finger hook 1047 on the side of one end 1041A may be textured.

[0143] Furthermore, in the syringe body 1041 of Example 2, the radius of curvature of the connecting outer peripheral surface 1061 is set to a curved surface of R2.5, which is larger than that of the connecting outer peripheral surface 61 of Example 1. As a result, in the syringe 1003 of Example 2, the label attached to the outer peripheral surface of the syringe body 1041 bends more gently at the connecting outer peripheral surface 1061 than in Example 1. For this reason, in the syringe 1003 of Example 2, the label attached to the outer peripheral surface of the syringe body 1041 can be made less likely to peel off than in Example 1.

[0144] [Static mixer] (Mixing chip main body) Figure 29A is a perspective view of the mixing chip main body 1019, and Figure 29B is a bottom view. Figure 29C is a cross-sectional view taken along line XXIX-XXIX shown in Figure 29B. Portions common to Example 1 are designated by reference numerals obtained by adding 1000 to the reference numerals in Figures 12A, 12B, and 13, and descriptions thereof will be omitted.

[0145] The mixing tip main body 1019 of Example 2 has a cylindrical base 1087, similar to Example 1. A flange 1087C extending radially outward is formed on the outer periphery of the base 1087. Two insertion portions 1089, 1089' and a pair of rotational engagement pieces 1091, 1091' are formed on a first end surface 1087A of the base 1087 facing the syringe 1003. A paste passage 1029 is formed inside the insertion portion 1089, and a paste passage 1029' is formed inside the insertion portion 1089'. Furthermore, a backflow prevention wall 1035 and an element group 1039 extending from the tip of the backflow prevention wall 1035 are formed on a second end surface 87B opposite the first end surface 87A of the base 1087.

[0146] In the mixing tip main body 1019 of Example 2, the length dimension L1 along the longitudinal direction X of the base 1087 is shorter than that of the base 87 of the mixing tip main body 19 of Example 1. On the other hand, the length dimension L2 along the longitudinal direction X of the backflow prevention wall 1035 of Example 2 is longer than that of the backflow prevention wall 35 of Example 1. Therefore, the overall length L3 along the longitudinal direction X of the mixing tip main body 1019 (the length from the tip of the insertion portion 1089, 1089' to the tip of the element group 1039) is set to the same length as that of the mixing tip main body 19 of Example 1.

[0147] Furthermore, in the mixing tip main body 1019 of Example 2, the tapered portion on the distal surface 1029C of the paste passage 1029 is formed in the region from the inlet hole 1029A to a position midway along the paste passage 1029. That is, the distal surface 1029C of Example 2 is formed in a tapered shape from the inlet hole 1029A to a position midway along the paste passage 1029, gradually approaching the central axis CA as it approaches the outlet hole 1029B. Note that the angle of the tapered portion, i.e., the angle θ formed by the distal surface 1029C and a straight line C1 passing through the center point of the inlet hole 1029A and extending in the longitudinal direction X, is set to 45° here.

[0148] The region of the distal surface 1029C from the tapered portion to the outflow hole 1029B extends parallel to the proximal surface 1029D and the central axis CA, and is aligned with the proximal surface 1029D and the central axis CA. In other words, the area of ​​the cross section of the paste passage 1029 of Example 2 that is perpendicular to the central axis CA (longitudinal direction X) gradually decreases at a constant rate from the inflow hole 1029A to a position midway along the paste passage 1029, but is the same size as the opening area of ​​the outflow hole 1029B from the position midway along the paste passage 1029 to the outflow hole 1029B.

[0149] In this way, the tapered portion of the distal surface 1029C is formed in the region from the inlet hole 1029A to a position halfway along the paste passage 1029, so that the paste injector 1001 of Example 2 can reduce the amount of paste flowing into the paste passage 1029 compared to the paste passage 29 of Example 1 while suppressing the formation of air bubble accumulation within the paste passage 1029, and can also reduce the amount of paste remaining in the paste passage 1029.

[0150] The paste passage 1029' has the same configuration as the paste passage 1029, and therefore the reference numerals of the components of the paste passage 1029 are marked with an "'" and the description thereof will be omitted. Also in the second embodiment, the paste passage 1029 and the paste passage 1029' are formed to have the same size and are symmetrical in shape along the width direction Y with the center axis CA as the center.

[0151] (Mixer housing) Figure 30A is a perspective view of mixer housing 1021, and Figure 30B is a cross-sectional view taken along line XXX-XXX shown in Figure 30A. Portions common to those in Example 1 are given reference numerals obtained by adding 1000 to the reference numerals given in Figures 14A and 15, and descriptions thereof will be omitted.

[0152] The mixer housing 1021 of Example 2 has the same basic shape as the mixer housing 21 of Example 1. That is, the mixer housing 1021 of Example 2 includes a base housing portion 1093 and an element housing portion 1037.

[0153] The base housing 1093 includes a circular end wall 1093A that covers the second end surface 1087B of the base 1087 of the mixing tip main body 1019, and a peripheral wall 1093B that surrounds the base 1087 and has a tip that contacts the flange 1087C. The element housing 1037 extends in the longitudinal direction X from a through hole formed in the center of the end wall 1093A, and has a guide tip engagement groove 1037A formed on its outer circumferential surface.

[0154] A recess 1093C is provided on the inner wall of the end wall portion 1093A at a position facing the outlet holes 1029B, 1029B' of the mixing tip body 1019. An intermediate passage 1031 is formed inside the inner member IM and is partitioned by the base 1087, the backflow prevention wall 1035, and the recess 1093C (see FIG. 27).

[0155] Here, the length along the longitudinal direction X from the flange portion 1087C to the second end face 1087B of the base portion 1087 of the mixing tip main body 1019 of Example 2 is shorter than that of Example 1. Therefore, in the mixer housing 1021 of Example 2, the length dimension L4 along the longitudinal direction X of the peripheral wall portion 1093B that surrounds the base portion 1087 and whose tip is in contact with the flange portion 1087C is shorter than that of the peripheral wall portion 93B of the mixer housing 21 of Example 1.

[0156] (Mixer exterior body) Figure 31A is a front view of mixer exterior body 1023, Figure 31B is a side view, Figure 31C is a plan view, and Figure 31D is a bottom view. Also, Figure 31E is a cross-sectional view taken along line XXXIE-XXXIE shown in Figure 31C, Figure 31F is a cross-sectional view taken along line XXXIF-XXXIF shown in Figure 31C, and Figure 31G is a cross-sectional view taken along line XXXIG-XXXIG shown in Figure 31A. Portions common to Example 1 are designated by reference numerals obtained by adding 1000 to the reference numerals used in Figures 16A to 16C, 17, and 18, and descriptions thereof will be omitted.

[0157] The mixer exterior body 1023 of Example 2 includes a top wall portion 1095, a first peripheral wall portion 1097 rising from the edge of the top wall portion 1095, and a second peripheral wall portion 1099 extending continuously via a step from the first peripheral wall portion 1097. As in Example 1, the interior of the mixer exterior body 1023 is formed with a first space S1 surrounded by the top wall portion 1095 and the first peripheral wall portion 1097, and a second space S2 surrounded by the second peripheral wall portion 1099 (see FIGS. 31E and 31F ).

[0158] The top wall 1095 has a regular hexagonal outer periphery, a top through-hole 1101 formed in the center, and an arrow AR2 indicating the position of a recess 1107A engraved on the surface (see FIG. 31C). The arrow AR2 is engraved at a position that overlaps the recess 1107A along the central axis CA. The recess 1107A is one of the engaged portions 1107, which will be described later.

[0159] When viewed along the central axis CA, the outer peripheral surface of the first peripheral wall portion 1097 is a regular hexagon as shown in Fig. 31C. When viewed along the central axis CA, the inner peripheral surface of the first peripheral wall portion 1097 is a circle as shown in Fig. 31D. The inner peripheral surface of the first peripheral wall portion 1097 is formed with a circumferential groove 1103, a pair of first engaged grooves 1105A, 1105A', and a pair of second engaged grooves 1105B, 1105B'.

[0160] When viewed along the central axis CA, the second peripheral wall portion 1099 has an outer peripheral surface that curves in an arc shape centered on the central axis CA, with a portion of the outer peripheral surface being teardrop-shaped and pointed outward, as shown in FIG. 31C . The pointed portion of the outer peripheral surface of the second peripheral wall portion 1099 is a sharpened portion 1099a, and the tip of the sharpened portion 1099a is aligned with the direction indicated by the arrow AR2 formed on the top wall portion 1095. Furthermore, the sharpened portion 1099a is formed with a protrusion 1099b that protrudes along the central axis CA from an end surface 1099B of the second peripheral wall portion 1099 (the opening of the mixer exterior body 1023 into which the syringe 1003 is inserted). Therefore, the protrusion 1099b is formed at a position that coincides with the position of the recess 1107A, one of the engagement portions 1107, in the circumferential direction about the central axis CA.

[0161] The inner peripheral surface of the second peripheral wall portion 1099 is formed with a step portion 1098, a second step portion 1098A, and an engaged portion 1107 made up of three recesses 1107A, 1107B, and 1107C.

[0162] The step portion 1098 is formed at the boundary between the first peripheral wall portion 1097 and the second peripheral wall portion 1099, and is a stepped uneven portion that narrows the inner diameter of the mixer outer casing 1023 toward the top wall portion 1095. The step portion 1098 extends in the circumferential direction (the rotation direction of the inner member IM), and when the static mixer 1007 is attached to the tip of the syringe 1003, the circular wall portion 1041a of the syringe 1003 abuts against the step portion 1098 (see FIG. 27 ).

[0163] The second step portion 1098A is a stepped unevenness that narrows the inner diameter of the mixer outer casing 1023 toward the top wall portion 1095, and is formed at a position closer to an end surface 1099B of the second peripheral wall portion 1099 than the step portion 1098. The second step portion 1098A extends in the circumferential direction (the rotation direction of the inner member IM), and when the static mixer 1007 is attached to the tip of the syringe 1003, a step portion 1049c formed on the outer peripheral surface of the paste storage chamber 1049, 1049' of the syringe 1003 abuts against the second step portion 1098A (see FIG. 27 ).

[0164] Similar to Example 1, the recesses 1107A, 1107B, and 1107C have first grooves 1107Aa, 1107Ba, and 1107Ca, respectively, and second grooves 1107Ab, 1107Bb, and 1107Cb. Furthermore, windows 1109A, 1109B, and 1109C penetrating the second peripheral wall 1099 are formed at positions corresponding to the second grooves 1107Ab, 1107Bb, and 1107Cb, respectively. The first grooves 1107Aa, 1107Ba, and 1107Ca open to the second stepped portion 1098A and extend along the longitudinal direction X (central axis CA) to the stepped portion 1098.

[0165] Furthermore, the mixer exterior body 1023 of Example 2 is formed with a cylindrical wall portion 1098B that rises from the edge of the second step portion 1098A along the central axis CA and forms an opening of the mixer exterior body 1023. The cylindrical wall portion 1098B is a cylindrical wall surface that surrounds the periphery of the step portion 1049c formed on the outer peripheral surface of the paste storage chamber 1049, 1049' when the static mixer 1007 is attached to the tip of the syringe 1003. Because the cylindrical wall portion 1098B rises from the edge of the second step portion 1098A, the first groove portions 1107Aa, 1107Ba, and 1107Ca are each open inside the cylindrical wall portion 1098B. In other words, the cylindrical wall portion 1098B protrudes along the central axis CA beyond the engaged portion 1107.

[0166] [Cap] (Cap exterior body) Fig. 32A is a front view of cap exterior body 1027, Fig. 32B is a side view, Fig. 32C is a plan view, and Fig. 32D is a bottom view. Also, Fig. 32E is a cross-sectional view taken along line XXXIIE-XXXIIE shown in Fig. 32C, Fig. 32F is a cross-sectional view taken along line XXXIIIF-XXXIIF shown in Fig. 32C, and Fig. 32G is a cross-sectional view taken along line XXXIIG-XXXIIG shown in Fig. 32A. Portions common to Example 1 are designated by reference numerals obtained by adding 1000 to the reference numerals used in Figs. 21A to 21C, 22, and 23, and description thereof will be omitted.

[0167] Furthermore, the cap inner member 1025 in the cap 1011 of the second embodiment has the same configuration as that of the first embodiment, and therefore the description thereof will be omitted.

[0168] Cap exterior body 1027 of Example 2 includes a top wall portion 1119, a first circumferential wall portion 1121 rising from the edge of top wall portion 1119, and a second circumferential wall portion 1123 extending continuously via a step from first circumferential wall portion 1121. Also, inside cap exterior body 1027, as in Example 1, a first space S1 surrounded by top wall portion 1119 and first circumferential wall portion 1121 and a second space S2 surrounded by second circumferential wall portion 1123 are formed (see FIGS. 32E and 32F ).

[0169] The top wall portion 1119 is a portion that closes the first space S1. Unlike the mixing tip main body portion 1019, the top wall portion 1119 is made of a curved plate member and does not have a top through-cylinder formed in the center. An arrow AR2 indicating the position of a recess 1129A (described later) is engraved on the surface of the top wall portion 1119 (see FIG. 32C). The arrow AR2 is engraved at a position that overlaps the recess 1129A along the central axis CA. The recess 1129A is one of the engaged portions 1129 (described later).

[0170] When viewed along the central axis CA, the outer peripheral surface of the first circumferential wall portion 1121 has a regular hexagonal shape as shown in Fig. 32C. When viewed along the central axis CA, the inner peripheral surface of the first circumferential wall portion 1121 has a circular shape as shown in Fig. 32D. The inner peripheral surface of the first circumferential wall portion 1121 is formed with a circumferential groove 1125, a pair of first engaged grooves 1127A, 1127A', and a pair of second engaged grooves 1127B, 1127B'.

[0171] When viewed along the central axis CA, the second circumferential wall portion 1123 has an outer peripheral surface that curves in an arc shape centered on the central axis CA, with a portion of the outer peripheral surface being teardrop-shaped and pointed outward, as shown in FIG. 32C . The pointed portion of the outer peripheral surface of the second circumferential wall portion 1123 is a sharpened portion 1123a, and the tip of the sharpened portion 1123a is aligned with the direction indicated by the arrow AR2 formed on the top wall portion 1119. Furthermore, the sharpened portion 1123a is formed with a protrusion 1123b that protrudes along the central axis CA from an end surface 1123B of the second circumferential wall portion 1123 (the opening of the cap exterior body 1027 into which the syringe 1003 is inserted). Therefore, the protrusion 1123b is formed at a position that coincides with the position of the recess 1129A, one of the engagement portions 1129, in the circumferential direction about the central axis CA.

[0172] The inner peripheral surface of the second peripheral wall portion 1123 is formed with a step portion 1120, a second step portion 1120A, and an engaged portion 1129 made up of three recesses 1129A, 1129B, and 1129C.

[0173] Step portion 1120 is formed at the boundary between first circumferential wall portion 1121 and second circumferential wall portion 1123, and is a stepped unevenness that narrows the inner diameter of cap exterior body 1027 toward top wall portion 1119. Step portion 1120 extends in the circumferential direction (the rotation direction of inner member IM), and when cap 1011 is attached to the tip of syringe 1003, circular wall portion 1041a of syringe 1003 abuts against step portion 1120 (see FIG. 27 ).

[0174] The second step portion 1120A is a stepped unevenness that narrows the inner diameter of the cap exterior body 1027 toward the top wall portion 1119, and is formed at a position closer to an end surface 1123B of the second circumferential wall portion 1123 than the step portion 1120. The second step portion 1120A extends in the circumferential direction (the rotation direction of the inner member IM), and when the cap 1011 is attached to the tip of the syringe 1003, a step portion 1049c formed on the outer peripheral surface of the paste storage chamber 1049, 1049′ of the syringe 1003 abuts against the second step portion 1120A (see FIG. 27 ).

[0175] Similar to Example 1, the recesses 1129A, 1129B, and 1129C have first grooves 1129Aa, 1129Ba, and 1129Ca, respectively, and second grooves 1129Ab, 1129Bb, and 1129Cb. Furthermore, windows 1131A, 1131B, and 1131C penetrating the second peripheral wall 1123 are formed at positions corresponding to the second grooves 1129Ab, 1129Bb, and 1129Cb, respectively. The first grooves 1129Aa, 1129Ba, and 1129Ca are open to the second stepped portion 1120A and extend along the longitudinal direction X (central axis CA) to the stepped portion 1120.

[0176] Furthermore, the cap exterior body 1027 of Example 2 is formed with a cylindrical wall portion 1120B that rises from the edge of the second step portion 1120A along the central axis CA and forms an opening of the cap exterior body 1027. The cylindrical wall portion 1120B is a cylindrical wall surface that surrounds the periphery of the step portion 1049c formed on the outer circumferential surface of the paste storage chamber 1049, 1049' when the cap 1011 is attached to the tip of the syringe 1003. As the cylindrical wall portion 1120B rises from the edge of the second step portion 1120A, the first groove portions 1129Aa, 1129Ba, and 1129Ca are each opened inside the cylindrical wall portion 1120B. In other words, the cylindrical wall portion 1120B protrudes along the central axis CA beyond the engaged portion 1129.

[0177] Although the first and second embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and it goes without saying that modifications are possible within the scope of the technical concept of the present invention.

[0178] For example, the paste injector 1 of Example 1 has two paste passages 29, 29'. However, the paste passages only need to be arranged side by side on a circle around the central axis, so it goes without saying that three or more paste passages may be provided.

[0179] In addition to the above descriptions of Examples 1 and 2, the following is further disclosed: (1) A static mixer comprising: a plurality of paste passages through which a plurality of types of paste individually stored in a syringe extending in the longitudinal direction and having inlet and outlet holes pass; an intermediate passage that guides the plurality of types of paste from the outlet holes to a joining position; and a mixing passage through which the plurality of types of paste that have joined at the joining position pass while being mixed, wherein the plurality of paste passages are arranged side by side on a circumference centered on a central axis of the syringe and extend in the longitudinal direction, and wherein an inner circumferential surface of each of the plurality of paste passages has a tapered portion formed on at least a portion of a distal surface away from the central axis that tapers toward the central axis as it moves from the inlet to the outlet hole, and the opening area of ​​the inlet hole is larger than the opening area of ​​the outlet hole. (2) The static mixer according to (1), wherein the tapered portion extends from the inlet to the outlet hole. (3) The static mixer according to (1), characterized in that the tapered portion is formed in a region from the inlet hole to a midpoint of the paste passage, and the distal surface extends along the central axis in a region from the tapered portion to the outlet hole. (4) The static mixer according to any one of (1) to (3), characterized in that a proximal surface of the inner circumferential surface of each of the plurality of paste passages, which is closer to the central axis, extends along the central axis. (5) The static mixer according to any one of (1) to (4), characterized in that the center point of the inlet hole is closer to the central axis than the center point of the inlet hole. (6) The static mixer according to any one of (1) to (5), characterized in that the intermediate passage is provided with a backflow prevention wall that partitions the intermediate passage and prevents the paste coming out of the outlet hole from flowing into other outlet holes. (7) The static mixer according to (6), characterized in that the backflow prevention wall has a curved surface formed at its base portion that directs the paste toward the joining position, and extends along the central axis to the joining position.(8) The static mixer according to any one of (1) to (7), which is used to mix the plurality of pastes to prepare a dental material and to inject the dental material. (9) A paste injector equipped with the static mixer according to any one of (1) to (8). CROSS-REFERENCE TO RELATED APPLICATIONS

[0180] This application claims priority based on Japanese Patent Application No. 2023-108654, filed with the Japan Patent Office on June 30, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A static mixer comprising: a plurality of paste passages through which a plurality of types of pastes individually stored in a syringe extending in the longitudinal direction and having inlet and outlet holes pass; an intermediate passage that guides the plurality of types of pastes that emerge from the outlet holes to a joining position; and a mixing passage through which the plurality of types of pastes that have joined at the joining position pass while being mixed, wherein the plurality of paste passages are arranged side by side on a circumference centered on a central axis of the syringe and extend in the longitudinal direction, wherein at least a portion of an inner circumferential surface of each of the plurality of paste passages has a tapered section that is tapered toward the central axis as it moves from the inlet to the outlet hole, and wherein an opening area of ​​the inlet hole is larger than an opening area of ​​the outlet hole.

2. The static mixer according to claim 1, characterized in that the tapered portion extends from the inlet to the outlet.

3. The static mixer according to claim 1, characterized in that the tapered portion is formed in the region from the inlet hole to a position midway along the paste passage, and the distal surface extends along the central axis in the region from the tapered portion to the outlet hole.

4. A static mixer as claimed in any one of claims 1 to 3, characterized in that the proximal surface of the inner circumferential surface of each of the plurality of paste passages, which is close to the central axis, extends along the central axis.

5. The static mixer according to claim 1, characterized in that the center point of the inlet is closer to the central axis than the center point of the inlet.

6. A static mixer as claimed in claim 1, characterized in that the intermediate passage is provided with a backflow prevention wall that divides the intermediate passage and prevents the paste coming out of the outlet hole from flowing into other outlet holes.

7. The static mixer according to claim 6, characterized in that the backflow prevention wall has a curved surface at its base that directs the paste toward the joining position, and extends along the central axis to the joining position.

8. The static mixer according to claim 1, characterized in that the plurality of types of pastes are mixed together to prepare a dental material, which is then used for injecting the dental material.

9. A paste injector comprising the static mixer according to claim 1.

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