Dispensing nozzle, dispensing device, and automatic analysis device

Abstract

Provided is a technique for ensuring airtightness and fitting force in fitting between a dispensing nozzle and a tip. A dispensing nozzle according to the present disclosure suctions and discharges a fluid, the dispensing nozzle comprising a nozzle base part and a tip attached to the nozzle base part. Within a region surrounded by the outer wall of the nozzle base part and the inner wall of the tip when the nozzle base part is press-fitted into the tip, a recessed part where the outer wall of the nozzle base part and the inner wall of the tip do not come into contact with each other is provided to at least one of the outer wall of the nozzle base part and the inner wall of the tip. On the contact surface between the outer wall of the nozzle base part and the inner wall of the tip, the outer wall of the nozzle base part presses the inner wall of the tip, thereby maintaining a state in which the nozzle base part is press-fitted into the tip.

Description

Dispensing nozzle, dispensing device and automatic analyzer

[0001] The present disclosure relates to a dispensing nozzle, a dispensing device, and an automatic analyzer.

[0002] An automated analyzer analyzes a sample (e.g., a biological sample such as serum or urine) by adding a reagent or the like to the sample and measuring its physical properties. Such an automated analyzer includes a dispensing device for dispensing a predetermined amount of the sample (liquid or gas) or reagent. The dispensing device has a dispensing nozzle connected to a dispensing pump, and a disposable tip may be detachably attached to the tip of the dispensing nozzle (dispensing probe). Patent Document 1 discloses a technique for detecting the liquid level of a sample by detecting capacitance using a tip (see Abstract, paragraph 0019, etc.).

[0003] International Publication No. 2011 / 093347

[0004] In the method for detecting the liquid level of a sample as described in Patent Document 1, a stable electrical contact must be ensured between the dispensing nozzle and the tip, and it is therefore necessary to increase the contact area between the outer wall surface of the dispensing nozzle and the inner wall surface of the tip. However, this may result in insufficient airtightness and fitting force between the dispensing nozzle and the tip.

[0005] Therefore, the present disclosure provides a technique for ensuring airtightness and fitting strength of the fitting between the dispensing nozzle and the tip.

[0006] In order to solve the above problems, the dispensing nozzle of the present disclosure is a dispensing nozzle that aspirates and dispenses a fluid, and comprises a nozzle base and a tip that is attached to the nozzle base, and is characterized in that, within an area surrounded by the outer wall of the nozzle base and the inner wall of the tip when the nozzle base is pressed into the tip, at least one of the outer wall of the nozzle base and the inner wall of the tip has a recess that prevents the outer wall of the nozzle base from coming into contact with the inner wall of the tip, and is configured so that the outer wall of the nozzle base presses against the inner wall of the tip at the contact surface between the outer wall of the nozzle base and the inner wall of the tip, thereby maintaining the nozzle base pressed into the tip.

[0007] Further features related to the present disclosure will become apparent from the description of this specification and the accompanying drawings. Also, aspects of the present disclosure are achieved and realized by the elements and combinations of various elements and the aspects of the following detailed description and the appended claims. The description of this specification is merely exemplary and does not limit the scope or application of the claims of the present disclosure in any way.

[0008] According to the present disclosure, it is possible to ensure airtightness and fitting strength of the fitting between the dispensing nozzle and the tip.

[0009] 1 is a schematic diagram of a dispensing mechanism of an automatic analyzer according to a first embodiment; FIG. 2 is a diagram showing a process of mounting a tip having a sink mark on a nozzle base; FIG. 3 is a schematic diagram showing a modified example of the shape of the recess in the nozzle base; FIG. 4 is a schematic diagram showing an example of the position of the recess relative to the mounted tip; FIG. 5 is a schematic diagram showing another example of the position of the recess relative to the mounted tip; FIG. 6 is a schematic diagram showing a modified example of the structure of the dispensing nozzle; FIG. 7 is a schematic diagram of a dispensing nozzle according to a second embodiment; FIG. 8 is a schematic diagram of a dispensing nozzle according to a third embodiment; FIG. 9 is a schematic diagram of a dispensing nozzle according to a fourth embodiment; FIG. 10 is a schematic diagram of a dispensing nozzle according to a modified example of the fourth embodiment; FIG. 11 is a diagram showing a dispensing nozzle used in a dispensing mechanism of a conventional automatic analyzer; FIG. 12 is a diagram showing a process of mounting a tip having a sink mark on a nozzle base;

[0010] First, the problem that the present disclosure aims to solve will be described. Fig. 9 is a diagram showing a dispensing nozzle 201 used in a dispensing mechanism of a conventional automatic analyzer. The dispensing nozzle 201 has a hollow tip 8 made of, for example, resin, and a nozzle base 207 to which the tip 8 is attached. A driving mechanism 204 such as an actuator and a capacitance detection unit 206 are connected to the nozzle base 207. A detection signal from the capacitance detection unit 206 is sent to a control unit 205. The control unit 205 controls the driving of the driving mechanism 204.

[0011] The dispensing mechanism aspirates the required specimen using this tip 8 and dispenses the aspirated specimen into a plurality of reaction vessels (not shown) or the like held upright. The nozzle base 207 is substantially cylindrical and tapered, with its diameter decreasing toward the tip, and is provided with an outer wall inclined surface 213. The tip 8 is shaped like an elongated cone, with its inner wall provided with an inner wall inclined surface 15. The tip 8 is provided with an opening 14 at its base end, into which the nozzle base 207 is inserted. The tip 8 is provided with an opening 19 at its tip end, for aspirating and discharging the specimen.

[0012] The work of attaching the tip 8 to the nozzle base 207 is performed as follows. The tip 8 is held upright in a predetermined position in advance. First, the drive mechanism 204 transports the nozzle base 207 to a position above the tip 8. Next, the drive mechanism 204 moves the nozzle base 207 vertically downward, and then presses the nozzle base 207 vertically until the nozzle base 207 is engaged with the tip 8 and can sufficiently hold it.

[0013] When the nozzle base 207 is pressed vertically by the drive mechanism 204, the outer wall inclined surface 213 of the nozzle base 207 comes into contact with the inner wall inclined surface 15 of the tip 8. Furthermore, the outer wall inclined surface 213 of the nozzle base 207 presses against the inner wall inclined surface 15, and they fit together while maintaining airtightness within the tip 8, thereby holding the tip 8 to the nozzle base 207. The region of the inner wall inclined surface 15 of the tip 8 that comes into contact with the outer wall inclined surface 213 of the nozzle base 207 has a thick portion 23 that is thick enough to withstand the pressure of the nozzle base 207. The airtightness of the fit and the fitting force are ensured by increasing the contact area between the outer wall inclined surface 213 and the inner wall inclined surface 15. If the contact surface area between the nozzle base 207 and the tip 8 is increased, it becomes necessary to increase the thick portion 23 of the tip 8 accordingly. However, the thick portion 23 is prone to variations in shape due to sink marks, which can cause inconveniences described below.

[0014] 10A and 10B are diagrams showing the process of attaching a tip 80 with a sink mark to a nozzle base 207. As shown in FIG. 10A, a sink mark 24 has formed on the inner wall of the thick portion 23 of the tip 80, creating a depression of several μm to several tens of μm relative to the original inner wall inclined surface 15 (dashed line). The tip 80 is held by the tip holder 22 so that the opening 14 faces upward. The nozzle base 207 is transported by the drive mechanism 204 to a position vertically above the opening 14 of the tip 80. The drive mechanism 204 then moves the nozzle base 207 vertically downward (see FIG. 10A).

[0015] 10(B), the nozzle base 207 is inserted while being guided by the guide surface 16 at the tip of the nozzle base 207 along the opening 14 and the inclined inner wall surface 15, and the inclined outer wall surface 213 of the nozzle base 207 comes into contact with the inclined inner wall surface 15 of the tip 80. At this time, the inner wall of the thick portion 23 of the tip 80 is recessed from the original inclined inner wall surface 15 due to the sink mark 24, so that a ring-shaped sealed space 225 is formed between the contact surfaces.

[0016] As shown in FIG. 10C , the nozzle base 207 is further moved downward by the driving mechanism 204, and the nozzle base 207 is pressed into the tip 80 while the outer wall inclined surface 213 slides along the inner wall inclined surface 15. At this time, the thick portion 23 and the sink mark 24 of the tip 80 deform along the outer wall inclined surface 213 of the nozzle base 207, compressing the sealed space 225. At this time, compressed fluid (e.g., liquid such as water) may infiltrate the contact surface between the nozzle base 207 and the tip 80. This lubricates the contact surface, reducing the engagement force of the tip 80 with the nozzle base 207, which may prevent the tip 80 from being attached to the nozzle base 207 (see FIG. 10D ). In addition to the engagement force, the infiltration of compressed fluid into the contact surface between the nozzle base 207 and the tip 80 may also affect the airtightness of the fit and the ability to detect the sample liquid level, potentially affecting the accuracy of sample dispensing.

[0017] As described above, even if there is a sink mark on the tip or the contact surface between the nozzle base and the tip is lubricated, it is necessary to ensure airtightness of the fitting, fitting force, and sample liquid level detection performance. Therefore, embodiments of the present disclosure will be described below with reference to the drawings. In the drawings, components having similar functions are assigned similar reference numerals, and redundant explanations may be omitted.

[0018] [First Embodiment] <Configuration Example of Dispensing Mechanism> Fig. 1 is a schematic diagram of a dispensing mechanism 1 of an automatic analyzer according to a first embodiment. The dispensing mechanism 1 is configured to perform a dispensing operation in which a liquid, such as a specimen or a reagent, and, if necessary, a gas, such as air, is sucked into a dispensing nozzle 2 and then dispensed into a predetermined container. The automatic analyzer is configured to be capable of holding one or more dispensing mechanisms 1, specimen containers that contain specimens, reagent containers that contain reagents, and reaction containers in which the specimen and reagent are mixed. As other components of the automatic analyzer can be well-known, detailed description thereof will be omitted.

[0019] As shown in Figure 1, the dispensing mechanism 1 includes a dispensing nozzle 2, a dispensing pump 3, a drive mechanism 4 for the dispensing nozzle 2, a control unit 5, and a capacitance detection unit 6. Figure 1 shows a state in which a tip 8 is attached to a nozzle base 7 of the dispensing nozzle 2. The tip of the nozzle base 7 and the tip 8 are shown in cross section.

[0020] The nozzle base 7 is substantially cylindrical. A flow path 9 filled with a fluid that serves as a pressure medium is formed within the nozzle base 7. A dispensing pump 3 is connected to the dispensing nozzle 2 via a flow path 10. The dispensing pump 3 has a cylinder and a piston. The dispensing nozzle 2 performs aspirating and discharging operations of specimens, reagents, etc. due to pressure changes in the fluid caused by the forward and backward movement of the piston. The driving mechanism 4 is, for example, an actuator, and is configured to transport the dispensing nozzle 2 in three dimensions. A detailed description of the configuration of the driving mechanism 4 will be omitted.

[0021] The control unit 5 is realized by, for example, a microcomputer. The control unit 5 controls the operations of the dispensing pump 3, the drive mechanism 4, and the capacitance detection unit 6, and also controls the entire dispensing mechanism 1. The capacitance detection unit 6 is connected to the dispensing nozzle 2 and the control unit 5. The control unit 5 is configured to detect the attachment state of the tip 8 and the sample liquid level from changes in the capacitance of the dispensing nozzle 2 received from the capacitance detection unit 6. Known means for detecting the attachment state of the tip 8 and the sample liquid level by the capacitance detection unit 6 can be used, so a detailed description will be omitted.

[0022] The material of the nozzle base 7 can be, for example, a metal such as stainless steel or titanium. The material of the tip 8 can be, for example, a resin, particularly PE resin (polyethylene). The material of the tip 8 can also be PC resin (polycarbonate), PS resin (polystyrene), PMMA resin (acrylic), or PET resin (polyethylene terephthalate) depending on the application. The color of the tip 8 can be selected appropriately depending on the application, such as transparent, translucent, or colored.

[0023] The nozzle base 7 has an outer wall inclined surface 13 for holding the tip 8 by frictional force. The nozzle base 7 has a recess 17. The recess 17 is provided over the entire circumferential direction of the nozzle base 7. As a result, the outer wall inclined surface 13 is separated into the base end 11 and the tip end 12 by the recess 17. The recess 17 can be formed, for example, by lathe processing. The lower diagram in FIG. 1 shows an enlarged view of the vicinity of the recess 17. As shown in this enlarged view, the side surface of the nozzle base 7 at the recess 17 can be parallel to the vertical direction. Alternatively, the side surface of the nozzle base 7 at the recess 17 can be parallel to the outer wall inclined surface 13. The length of the recess 17 can be, for example, 10% to 80% of the length of the region where the nozzle base 7 and the tip 8 face each other. However, the dimensions of the recess 17 are not limited to this.

[0024] Furthermore, an inclined surface 18 having an angle different from that of the outer wall inclined surface 13 is formed at the boundary between the outer wall inclined surface 13 and the recessed portion 17. By providing the inclined surface 18, it is possible to prevent the inner wall of the tip 8 from biting into the corner of the recessed portion 17 and damaging the inner wall of the tip 8 when the tip 8 is attached or removed. Here, the same effect can be obtained even if the cross-sectional shape of the inclined surface 18 is a curved shape such as an arc. The angle of the inclined surface 18 with respect to the inner wall inclined surface 15 is not particularly limited, but can be, for example, 30° to 60°. However, the inclined surface 18 does not necessarily have to be provided.

[0025] A rounded guide surface 16 is formed at the tip of the tip portion 12. When the nozzle base 7 is inserted into the tip 8, the guide surface 16 is guided by the inner wall inclined surface 15 of the tip 8. The inner wall of the opening 14 of the tip 8 is also formed with an inner wall inclined surface 15 having the same inclination angle as the outer wall inclined surface 13. When the nozzle base 7 is inserted into the tip 8, the inner wall inclined surface 15 of the tip 8 and the outer wall inclined surface 13 of the nozzle base 7 come into contact. At this time, the fluid present between the outer wall inclined surface 13 and the inner wall inclined surface 15 is allowed to escape into the recess 17, ensuring a contact surface.

[0026] 2A and 2B are diagrams illustrating a process for attaching a tip 80 having a sink mark to a nozzle base 7. As shown in FIG. 2A, the inner wall of the thick portion 23 of the tip 80 is recessed below the original inner wall inclined surface 15 due to the sink mark 24. The tip 80 is held by the tip holder 22 so that the opening 14 faces upward. The nozzle base 7 is transported by the drive mechanism 4 to a position vertically above the opening 14 of the tip 80. The drive mechanism 4 then moves the nozzle base 7 vertically downward. The guide surface 16 at the tip of the nozzle base 7 is inserted while being guided by the opening 14 and the inner wall inclined surface 15, and the outer wall inclined surface 13 of the base end 11 and tip end 12 of the nozzle base 7 contacts the inner wall inclined surface 15. At this time, as shown in FIG. 2B, the inner wall of the thick portion 23 of the tip 80 is recessed due to the sink mark 24, forming a ring-shaped sealed space 25 between the contact surfaces.

[0027] Next, the nozzle base 7 is moved further downward by the drive mechanism 4, and the nozzle base 7 is press-fitted into the tip 80 while the outer wall inclined surface 13 slides along the inner wall inclined surface 15. As a result, the outer wall inclined surface 13 of the nozzle base 7 presses against the inner wall inclined surface 15 of the tip 80, enabling the tip 80 to be positioned. At this time, as shown in FIG. 2(C), the thick portion 23 of the tip 80 deforms along the outer wall inclined surface 13 of the nozzle base 7, compressing the sealed space 25 and the fluid within the sealed space 25. By allowing the compressed fluid to escape into the recess 17 provided in the nozzle base 7, it is possible to prevent the fluid from entering the contact surface between the nozzle base 7 and the tip 80.

[0028] The above operations complete the attachment of the tip 80 to the nozzle base 7. As shown in Figure 2(D), the drive mechanism 4 moves the nozzle base 7, to which the tip 80 has been attached, upward. As described above, by providing the recess 17 in the nozzle base 7, it is possible to ensure airtightness of the fit, fitting force, and sample liquid level detection performance.

[0029] <Modified Examples of Recess> Figure 3 is a schematic diagram showing several modified examples of the shape of the recess in the nozzle base 7. As shown in Figures 3(i) to 3(vii), the shape of the recess in the nozzle base 7 is not limited to that shown in Figure 1, and any suitable shape may be adopted as appropriate. Figures 3(i) to 3(v) show a side view of the nozzle base 7 and a cross-sectional view of the recess 17 in a direction perpendicular to the longitudinal axis of the nozzle base 7. Figures 3(vi) and 3(vii) show only a side view of the nozzle base 7.

[0030] The nozzle base 7 shown in Figure 3(i) has a contact surface 131 in the center of the recess 171 that contacts the inner wall inclined surface 15 of the tip 8. In other words, two recesses are provided parallel to each other and adjacent to each other along the axis of the nozzle base 7. This not only prevents fluid from entering the contact surface between the nozzle base 7 and the tip 8, but also ensures a wider contact surface between the tip 8 and the nozzle, thereby preventing the tip 8 from wobbling. Although the contact surface 131 is shown in Figure 3(i) as being on the same plane and at the same inclination angle as the outer wall inclined surface 13, this does not necessarily have to be the case.

[0031] The nozzle base 7 shown in Figure 3(ii) has a plurality of oval grooves 172 (oval, elliptical, or rounded rectangular grooves) extending parallel to the central axis of the nozzle base 7 on the circumference as recesses in the outer wall inclined surface 13. Since the outer wall inclined surface 13 that contacts the inner wall inclined surface 15 of the tip 8 is located between adjacent oval grooves 34, the contact surface between the tip 8 and the nozzle is ensured to be uniform in the region where the oval grooves 172 exist. This makes it possible to prevent the tip 8 attached to the nozzle base 7 from wobbling.

[0032] The nozzle base 7 shown in Figure 3 (iii) has two grooves 173 that are perpendicular to the axis of the nozzle base 7 in part of the outer wall inclined surface 13. Because a wide contact surface can be secured between the tip 8 and the nozzle base 7, not only is the compressed fluid released into the grooves 173 (recesses), but also wobbling of the tip 8 is prevented.

[0033] The nozzle base 7 shown in Figure 3(iv) has a plurality of hemispherical grooves 174 on the circumference of a portion of the outer wall inclined surface 13. The grooves 174 are arranged in two rows along the axis of the nozzle base 7, and in each row, the grooves 174 are lined up in the circumferential direction at predetermined intervals. This not only has the effect of allowing compressed fluid to escape into the grooves 174 (recesses), but also has the effect of preventing the tip 8 from wobbling.

[0034] 3(v), the cross-sectional shape of the recess 175 is rectangular. The cross-sectional shape of the recess 175 is not limited to a rectangular shape, and even if it is a polygonal shape, the same effect as when it is circular can be obtained.

[0035] The nozzle base 7 shown in Figure 3(vi) has a recess 176 in the outer wall inclined surface 13. The recess 176 has a bottom 1761 and an inclined surface 1762 that contact the outer wall inclined surface 13 on the tip side of the nozzle base 7 without any step. With this structure, when the tip 8 is attached or removed, the inner wall of the tip 8 bites into the corner formed by the recess 176 and the outer wall inclined surface 13, preventing damage to the inner wall of the tip 8. Note that the angle between the recess 176 and the outer wall inclined surface 13 is preferably an obtuse angle to prevent damage to the inner wall of the tip 8.

[0036] The nozzle base 7 shown in FIG. 3( vii ) has a recess 177 in the outer wall inclined surface 13. The recess 177 has an inclined surface 1771 and an inclined surface 1772. With this structure, when the tip 8 is attached or removed, the inner wall of the tip 8 can be prevented from biting into the corner formed by the outer wall inclined surface 13 and the inclined surface 1771 and the corner formed by the outer wall inclined surface 13 and the inclined surface 1772, thereby preventing damage to the inner wall of the tip 8. Note that the angle between the outer wall inclined surface 13 and the inclined surface 1771 and the angle between the outer wall inclined surface 13 and the inclined surface 1772 are preferably obtuse angles to prevent damage to the inner wall of the tip 8.

[0037] Figure 4A is a schematic diagram showing an example of the position of the recess relative to the attached tip 8. The shapes of the recesses in Figures 4A(i) to (vii) are the same as those in Figures 3(i) to (vii). In Figures 4A(i) to (vii), the recess is provided between the contact surfaces of the base end 11 and the tip end 12 of the outer wall inclined surface 13. The base end 11 and the tip end 12 each contact the inner wall inclined surface 15 of the tip 8 with a continuous surface on the circumference, thereby ensuring the fitting of the tip 8 and the sealing of the contact surface.

[0038] FIG. 4B is a schematic diagram showing another example of the position of the recess relative to the attached tip 8. In FIGS. 4B(i) to (iii), the recess is provided on the base end 111 side of the outer wall inclined surface 13. The shape of the recess 17 in FIG. 4B(i) is the same as that shown in FIG. 1. The nozzle base 7 shown in FIG. 4B(i) has a recess 17 at the base end 111 of the outer wall inclined surface 13 that does not contact the tip. The tip is fitted to the tip by contacting the inner wall inclined surface 15 of the tip 8 with a continuous surface on the circumference of the distal end 12, ensuring a tight seal of the contact surface. By providing the recess 17 at the base end 111 and opening the contact surface of the base end 111 with the tip 8, the effect of escaping fluid that affects the contact surface between the tip and the nozzle can be further improved.

[0039] The shape of the recess in Figure 4B(ii) is the same as that in Figure 3(ii). The nozzle base 7 shown in Figure 4B(ii) has a plurality of oval grooves 172 parallel to the central axis of the nozzle base 7 as recesses on the base end 112 of the outer wall inclined surface 13, arranged around the circumference. By opening a portion of the contact surface of the base end 112 with the tip 8, the same effect as the structure in Figure 4B(i) can be obtained, and the outer wall inclined surface 13 that contacts the inner wall inclined surface 15 of the inner wall is located between the plurality of oval grooves 172 arranged around the circumference, ensuring a uniform contact surface between the tip 8 and the nozzle base 7 in the area where the oval grooves 172 exist. This prevents the tip 8 attached to the nozzle base 7 from wobbling.

[0040] The shape of the recess in Figure 4B(iii) is the same as that in Figure 3(iii). The nozzle base 7 shown in Figure 4B(iii) has two grooves 173 that are recessed at the base end 113 of the outer wall inclined surface 13 and are perpendicular to the axis of the nozzle base 7. By opening up part of the contact surface of the base end 113 with the tip 8, the same effect as the structure in Figure 4B(i) can be obtained, and since the contact surface between the tip 8 and the nozzle base 7 can be secured over a wide area, the effect of preventing the tip 8 from wobbling can also be obtained.

[0041] FIG. 4C is a schematic diagram showing another example of the position of the recess relative to the attached tip 8. In FIGS. 4C(i) to (iii), the recess is provided on the tip side of the outer wall inclined surface 13. The shape of the recess in FIG. 4C(i) is the same as that in FIG. 1. The nozzle base 7 shown in FIG. 4C(i) has a recess 17 in the tip 121. The base end 11 contacts the tip 8 with a continuous surface along the circumference, thereby fitting the tip 8 and ensuring a tight seal on the contact surface. By providing the recess 17 in the tip 121 and leaving the contact surface between the tip 121 and the tip 8 open, the effect of escaping fluid that affects the contact surface between the tip 8 and the nozzle base 7 can be further improved.

[0042] The shape of the recess in Figure 4C(ii) is the same as that in Figure 3(ii). The nozzle base 7 shown in Figure 4C(ii) has a plurality of oval grooves 172 extending parallel to the central axis of the nozzle base 7 on the circumference as recesses in the tip portion 122. By opening a portion of the contact surface of the tip portion 122 with the tip 8, the same effect as the structure in Figure 4C(i) can be obtained, and the outer wall inclined surface 13 that contacts the inner wall inclined surface 15 of the tip 8 is located between the plurality of oval grooves 172 on the circumference, ensuring a uniform contact surface between the tip 8 and the nozzle base 7 in the area where the oval grooves 172 exist. This also has the effect of preventing the tip 8 attached to the nozzle base 7 from wobbling.

[0043] The shape of the recess in Figure 4C(iii) is the same as that in Figure 3(iii). The nozzle base 7 shown in Figure 4C(iii) has two grooves 173 perpendicular to the axis of the nozzle base 7 in part of the outer wall inclined surface 13 as recesses in the tip 123. By opening part of the contact surface of the tip 123 with the tip 8, the same effect as the structure in Figure 4C(i) can be obtained, and since the contact surface between the tip 8 and the nozzle base 7 can be secured over a wide area, the effect of preventing the tip 8 from wobbling can also be obtained.

[0044] FIG. 5 is a schematic diagram showing a modified structure of the dispensing nozzle 2. In the dispensing nozzle 2 shown in FIG. 5, the inclination angles of the base end outer wall inclined surface 114 and the tip end outer wall inclined surface 124 of the nozzle base 7 are different. The base end outer wall inclined surface 114 and the tip end outer wall inclined surface 124 do not need to be on the same plane or at the same angle. Even when the inclination angles of the base end outer wall inclined surface 114 and the tip end outer wall inclined surface 124 are different, providing a recess 17 in the area that contacts the inner wall of the tip 81 can prevent fluid from entering the contact surface between the nozzle base 7 and the tip 81. Note that the tip 81 in FIG. 5 has an inner wall inclined surface 152 that contacts the base end outer wall inclined surface 114 of the nozzle base 7 and an inner wall inclined surface 152 that contacts the tip end outer wall inclined surface 124.

[0045] Summary of the First Embodiment As described above, the dispensing mechanism 1 according to the first embodiment includes a dispensing nozzle 2 configured to aspirate and dispense liquids and gases (fluids). The dispensing nozzle 2 includes a nozzle base 7 and a tip 8 that is detachably attached to the nozzle base 7. A recess is provided in the nozzle base 7 (at least one of the nozzle base 7 and the tip 8) in the area where the nozzle base 7 and the tip 8 come into contact when the tip 8 is attached. The nozzle base 7 and the tip 8 do not come into contact in the recess. This structure allows fluid that has infiltrated the contact surface between the nozzle base 7 and the tip 8 to escape into the recess. This allows fluid to escape into the recess even when a tip with sink marks is attached or when the nozzle base 7 is lubricated with a fluid. This prevents fluid from infiltrating the contact surface between the nozzle base and the tip, ensuring airtightness of the fit, fitting force, and sample liquid level detection performance.

[0046] Second Embodiment In the first embodiment, a dispensing nozzle having a configuration in which a recess is provided in the nozzle base is described. In the second embodiment, a configuration in which a porous body having voids is provided in the nozzle base of the dispensing nozzle instead of forming a recess in the nozzle base is described.

[0047] FIG. 6 is a schematic diagram of a dispensing nozzle according to the second embodiment. As shown in FIG. 6, a portion of the surface of the nozzle base 71 according to the second embodiment is formed of a porous body 178. By allowing fluid compressed at the contact surface between the tip 80 and the nozzle base 71 to escape into the voids in the porous body 178, the fluid is prevented from penetrating the contact surface between the nozzle base 71 and the tip 80. In other words, the voids in the porous body 178 have the same function as the recess 17 described in the first embodiment. The diameter of the voids in the porous body 178 is not particularly limited as long as it does not impair the effects of the present disclosure. Furthermore, if the porous body 178 is made of a hard material such as metal or ceramic, the sink mark on the tip 80 will come into contact with the hard material when elastically deformed, allowing for a wider contact surface between the nozzle base 71 and the tip 80. Therefore, a higher mating force and sample liquid level detection performance can be ensured compared to when a recess is provided. The position, shape, size, and material of the porous body 178 are not limited to those shown in the figure, and can be changed as appropriate.

[0048] Third Embodiment In the third embodiment, a dispensing nozzle having a configuration in which the material of part of the nozzle base is changed will be described.

[0049] FIG. 7 is a schematic diagram of a dispensing nozzle 2 according to a third embodiment. The nozzle base 72 of this embodiment includes, in a portion of the area that comes into contact with the tip 8, a conductive material 721 whose surface is coated with or impregnated with a fluid 722 based on oil or grease (e.g., mineral oil) or water. The conductive material 721 may be, for example, a metal such as stainless steel or titanium. An enlarged view of the vicinity of the conductive material 721 is shown on the right side of FIG. 7. As shown in this enlarged view, the conductive material 721 has undulations 723 with a radial depth of several nanometers to several micrometers. The undulations 723 are, for example, processing marks. The surface of the undulations 723 is covered with the fluid 722.

[0050] This structure ensures a wide electrical contact between the nozzle base 72 and the chip 8 when they come into contact. Furthermore, by covering the surface of the nozzle base 72 with the fluid 722, the formation of an oxide film that would impede electrical conduction and the adhesion of dirt can be prevented, resulting in stable conduction. It is desirable for the fluid 722 to be conductive. Even if the fluid 722 is insulating, electrons can pass through the film of the fluid 722 due to the tunneling effect and move between the nozzle base 72 and the chip 8, thereby ensuring electrical conduction. This ensures stable electrical contact. The nozzle base 72 is provided with the recess 17 of the first embodiment, which allows excess fluid 722, which could affect the fit of the chip 8, to be removed from the contact surface between the nozzle base 72 and the chip 8. The configuration other than the nozzle base 72 is the same as in the first embodiment, so a description thereof will be omitted.

[0051] As in the third embodiment, by applying a fluid that serves as a surface protectant for electrical contacts to the nozzle base, it is possible to improve the adhesion of the electrical contact between the nozzle base and the conductive tip and the detection sensitivity of the sample liquid level. Surface protectants for electrical contacts typically use oils and greases as their base material, and when used on the contact surface between the nozzle base and the tip, the surface becomes lubricated, which can hinder the attachment of the tip to the nozzle base. In contrast, by providing the recess 17 in the nozzle base 72, even when the contact surface between the nozzle base 72 and the tip 8 is lubricated, the lubricating fluid can escape into the recess 17 in the nozzle base 72, thereby maintaining the mated state.

[0052] [Fourth embodiment] In the first to third embodiments, a configuration in which a recess is provided in the nozzle base of the dispensing nozzle has been described. Alternatively, the recess may be provided on the tip side. In the fourth embodiment, a configuration in which a recess is provided on the tip will be described.

[0053] FIG. 8A is a schematic diagram of a dispensing nozzle according to a fourth embodiment. The left side of FIG. 8A shows a tip 82 attached to a nozzle base 207. The center of FIG. 8A shows a longitudinal cross-sectional view of the tip 82. The right side of FIG. 8A shows a cross-sectional view of the thick portion in a direction perpendicular to the longitudinal direction of the tip 82 (cross-sectional view taken along line A-A' in the center of FIG. 8A). The nozzle base 207 does not have a recess. The inner wall of the tip 82 is provided with a recess 823 parallel to the central axis of the tip 82, extending from a center 821 of the thick portion to an opening 822.

[0054] FIG. 8B is a schematic diagram of a dispensing nozzle according to a modified example of the fourth embodiment. The left side of FIG. 8B shows a tip 83 attached to the nozzle base 207. The center of FIG. 8B shows a longitudinal cross-sectional view of the tip 83. The right side of FIG. 8B shows a cross-sectional view of the thick portion of the tip 83 in a direction perpendicular to the longitudinal direction of the tip 83 (the cross-sectional view taken along B-B' in the center of FIG. 8B). The inner wall of the tip 83 is provided with a recess 833 parallel to the central axis of the tip 83, extending from the center 831 of the thick portion to the tip tip side 832 of the contact surface.

[0055] As shown in Figures 8A and 8B, a recess is provided in the area of ​​the inner wall of the chip that comes into contact with the nozzle base. This allows fluid compressed at the contact surface between the chip and the nozzle base to escape into the recess in the chip, preventing it from penetrating the contact surface, even when a nozzle base 207 without a recess on the contact surface with the chip is attached. In this way, fluid that would otherwise affect the contact surface when the nozzle comes into contact with the chip can escape from the contact surface, ensuring airtightness, engagement force, and sample liquid level detection performance. Furthermore, the above effects can be enhanced by combining the chip of this embodiment with the nozzle bases having recesses of the first to third embodiments.

[0056] In this embodiment, the depth (diametric dimension) of the recess in the tip is set to 20 μm or more from the contact surface with the nozzle, so that the recess can be maintained even if the tip deforms when it comes into contact with the nozzle base. It is also possible to provide multiple recesses circumferentially on the inner wall of the tip, and to form a rib-shaped contact surface with the nozzle. In this shape, the recesses have a reduced-weight structure, which is expected to prevent sink marks during injection molding. Furthermore, the shape, dimensions such as depth and length, position, and number of recesses in the circumferential direction of the tip recess in this embodiment are not limited to those shown in FIGS. 8A and 8B and can be modified as appropriate.

[0057] [Modifications] The present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and it is not necessary to include all of the described configurations. Furthermore, a part of one embodiment can be replaced with a configuration of another embodiment. Furthermore, a configuration of another embodiment can be added to a configuration of one embodiment. Furthermore, a part of the configuration of each embodiment can be added to, deleted from, or substituted for a part of the configuration of another embodiment.

[0058] DESCRIPTION OF SYMBOLS 1... Dispensing mechanism (dispensing device) 2... Dispensing nozzle 3... Dispensing pump 4... Driving mechanism 5... Control unit 6... Capacitance detection unit 7... Nozzle base 8... Tip 9... Flow path 10... Flow path 11... Base end of nozzle base 12... Tip end of nozzle base 13... Outer wall inclined surface of nozzle base 14... Opening 15... Inner wall inclined surface 16... Guide surface 17... Recess 18... Inclined surface 19... Opening 22... Tip holder 23... Thick portion 24... Sink 25... Sealed space 80... Tip with sink 201... Dispensing nozzle 204... Driving mechanism 205... Control unit 206... Capacitance detection unit 207... Nozzle base 213... Outer wall inclined surface 225... Sealed space

Claims

1. A dispensing nozzle for aspirating and dispensing a fluid, comprising: a nozzle base; and a tip attached to the nozzle base, wherein within an area surrounded by the outer wall of the nozzle base and the inner wall of the tip when the nozzle base is press-fitted into the tip, at least one of the outer wall of the nozzle base and the inner wall of the tip has a recess that prevents the outer wall of the nozzle base from coming into contact with the inner wall of the tip, and wherein the outer wall of the nozzle base presses against the inner wall of the tip at the contact surface between the outer wall of the nozzle base and the inner wall of the tip, thereby maintaining the nozzle base pressed into the tip.

2. A dispensing nozzle according to claim 1, characterized in that at the contact surface between the outer wall of the nozzle base and the inner wall of the tip, the outer wall of the nozzle base has an inclined surface with a uniform, equal angle of inclination.

3. A dispensing nozzle according to claim 1, characterized in that the tip is positioned by the outer wall of the nozzle base pressing against the inner wall of the tip at the contact surface of the region.

4. A dispensing nozzle according to claim 1, wherein the outer wall of the nozzle base has a surface at a boundary with the recess that is at a different angle from the contact surface.

5. A dispensing nozzle according to claim 4, wherein the surface at an angle different from the contact surface is an inclined surface or a curved surface.

6. A dispensing nozzle according to claim 1, characterized in that the contact surface between the outer wall of the nozzle base and the inner wall of the tip has a contact surface that is continuous in the circumferential direction of the dispensing nozzle in at least a portion thereof.

7. A dispensing nozzle according to claim 1, characterized in that the recess extending parallel to the central axis of the tip is provided on at least a portion of the inner wall of the tip within the region.

8. A dispensing nozzle according to claim 1, characterized in that a porous body having gaps as the recesses is provided on at least a portion of the outer wall of the nozzle base within the area surrounded by the outer wall of the nozzle base and the inner wall of the tip.

9. A dispensing nozzle according to claim 1, wherein the nozzle base is at least partially made of a material impregnated and / or coated with a fluid based on oil, fat, and / or water.

10. A dispensing device comprising the dispensing nozzle according to claim 1.

11. An automatic analyzer comprising the dispensing device according to claim 10.

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