Precision dispenser actuator

Abstract

A dispenser system uses an actuator to depress or otherwise actuate a dispenser to dispense fluid. In one form, the actuator includes a stepper motor. Using the stepper motor, the stroke length of a pumping action to dispense the fluid can be varied and precisely controlled. The stepper motor can provide a wide range of stroke lengths, which in turn allows the system to have the ability to dispense a wide range of fluid volumes. To provide feedback control, the dispenser system includes a controller and a droplet sensor that senses one or more characteristics of a dispensed fluid droplet, such as volume. In one form, the droplet sensor includes a dual light curtain through which a dispensed fluid droplet passes. Based on the sensed droplet characteristics, the controller can adjust the stroke length of the pumping action from the stepper motor.

Description

[0001] Cross-references to related applications This application claims the benefit of U.S. Patent Application No. 63 / 557,659, filed February 26, 2024, which is incorporated herein by reference. Background Technology

[0002] In the field of medical diagnostics, tissue and / or cell samples are typically placed on glass slides for analysis. Liquid reagent solutions are also often applied to the slides to facilitate sample analysis. To improve testing accuracy, reagents need to be applied in a precise and consistent manner. However, this can be challenging when performing analyses on a commercial scale.

[0003] Therefore, improvements are needed in this area. Summary of the Invention

[0004] Dispenser systems for rare reagents are currently a reliable and cost-effective way to deliver reagents for staining reactions. While individual dispensers offer excellent repeatability, typically within the range of + / - 1–2 µl, it has been found that the accuracy difference between dispensers can be several times greater than the repeatability range of individual dispensers. This poses a challenge to controlling the reagent concentration during staining reactions on slides. Current dispenser actuation schemes are based on simple hammering motion by pressure actuators (such as hydraulic or pneumatic actuators), but this scheme is not convenient for controlling or adjusting the amount of pressure or actuation of the dispenser. The dispensing volume is entirely limited by the allowable internal stroke length of the piston, and the dispensing volume depends on the tolerances of the plastic components that make up the pump chamber and piston in the dispenser.

[0005] In view of this, unique dispenser systems and dispensing technologies have been developed to address these and other issues. Generally, the system includes one or more dispensers that facilitate the dispensing of multi-dose, fixed-volume reagents with high precision. The system uses mechanical downforce to dispense the reagent from the dispenser. Each dispenser has a pump chamber with a built-in refill mechanism that refills the pump chamber with reagent after the dispenser is released from actuation. Specifically, the system uses a microstepping motor to downforce or otherwise actuate the dispenser to dispense fluid. Using a stepper motor, the stroke length of the pumping action for dispensing fluid can be varied and precisely controlled. Stepper motors can provide a wide range of stroke lengths, which in turn allows the system to dispense a wide range of fluid volumes. To provide feedback control, the dispenser system includes a controller and a droplet sensor that senses one or more characteristics of the dispensed fluid droplets, such as volume. In one form, the droplet sensor includes a dual light curtain through which the dispensed fluid droplets pass. Based on the sensed droplet characteristics, the controller can adjust (and calibrate) the stroke length of the pumping action from the stepper motor. For example, if the sensed volume of the dispensed fluid is too large, the controller commands the stepper motor to reduce the stroke length, and conversely, if the dispensed volume is too small, the controller instructs the stepper motor to increase the stroke length when actuating the dispenser (for each individual dispenser). This feedback control facilitates precise and accurate reagent dispensing across a variety of dispensers.

[0006] With the increased dispensing volume range and feedback control now offered by stepper motors, dispensers have been improved in some examples to facilitate a wider range of volumes. The dispenser system no longer relies solely on mechanical limiting devices and other measures within the dispenser to control the dispensing fluid volume (which are highly susceptible to loose manufacturing tolerances), but instead utilizes precise actuation and feedback control provided by the stepper motor to control the dispensing volume. In one example, the internal structure of the dispenser has been improved to facilitate a larger dispensing volume, while in other examples, the internal structure has been improved to reduce the dispensing volume, such as from a nominal volume of 95 µl to 70 µl. With a wider volume range, the same dispenser can dispense a greater variety of fluids and can be used for a wider range of test programs. In one form, the stroke length limiter has been improved, and the lower inlet valve seal or seat has been improved to allow for the dispensing of larger volumes of fluid.

[0007] In yet another variation, the dispenser system includes a syringe for dispensing fluid to facilitate customized dispensing volumes, such as those typically required for research applications or titrations. In one form, the syringe is supported by a dispenser clamp. The dispenser clamp includes one or more clamping arms that hold the syringe. In another form, the syringe is supported by a syringe adapter. The syringe adapter includes an insert, such as a foam insert, configured to support the syringe during dispensing. In one version, the syringe adapter further includes a turntable adapter configured to couple the syringe to a turntable of the dispenser system.

[0008] The systems and technologies described and illustrated in this article involve several unique and innovative aspects. Some of these unique aspects are summarized below, but by no means all.

[0009] Aspect 1 involves a system in general.

[0010] Aspect 2 generally relates to a system according to any of the preceding aspects, which includes a controller.

[0011] Aspect 3 generally relates to a system according to any of the preceding aspects, wherein the controller includes a processor.

[0012] Aspect 4 generally relates to a system according to any of the preceding aspects, wherein the controller includes a memory.

[0013] Aspect 5 generally relates to a system according to any of the preceding aspects, which includes a glass slide.

[0014] Aspect 6 generally relates to a system as described in any of the preceding aspects, wherein a glass slide supports the tissue and / or cells to be analyzed.

[0015] Aspect 7 generally relates to systems described in any of the preceding aspects, which include fluids.

[0016] Aspect 8 generally relates to systems according to any of the preceding aspects, wherein the fluid contains a reagent.

[0017] Aspect 9 generally relates to a system according to any of the preceding aspects, wherein a fluid is configured to stain tissue on a glass slide.

[0018] Aspect 10 generally relates to systems described in any of the preceding aspects, wherein the fluid is a liquid.

[0019] Aspect 11 generally relates to a system according to any of the preceding aspects, which includes a distributor.

[0020] Aspect 12 generally relates to a system according to any of the preceding aspects, wherein a distributor is configured to distribute fluid.

[0021] Aspect 13 generally relates to a system according to any of the preceding aspects, wherein a dispenser is configured to dispense fluid onto a glass slide.

[0022] Aspect 14 generally relates to a system according to any of the preceding aspects, wherein the distributor includes a storage unit.

[0023] Aspect 15 generally relates to a system according to any of the preceding aspects, wherein a reservoir is configured to store fluid.

[0024] Aspect 16 generally relates to a system according to any of the preceding aspects, wherein the reservoir defines a reservoir chamber.

[0025] Aspect 17 generally relates to a system according to any of the preceding aspects, wherein a reservoir chamber is configured to store fluid.

[0026] Aspect 18 generally relates to a system according to any of the preceding aspects, wherein the reservoir has a cap.

[0027] Aspect 19 generally relates to a system according to any of the preceding aspects, wherein a cap is configured to be pressed to dispense fluid.

[0028] Aspect 20 generally relates to a system according to any of the preceding aspects, wherein the cap includes a flip cover.

[0029] Aspect 21 generally relates to a system according to any of the preceding aspects, wherein the distributor includes a pump.

[0030] Aspect 22 generally relates to a system according to any of the preceding aspects, wherein the reservoir and the pump are coupled in a reciprocating manner.

[0031] Aspect 23 generally relates to a system according to any of the preceding aspects, wherein the reservoir and the pump are coupled in a telescoping manner.

[0032] Aspect 24 generally relates to a system according to any of the preceding aspects, wherein the dispenser includes a spring disposed between a reservoir and a pump.

[0033] Aspect 25 generally relates to a system according to any of the preceding aspects, wherein a spring is configured to bias a reservoir away from a pump.

[0034] Aspect 26 generally relates to a system according to any of the preceding aspects, wherein the distributor includes an inlet valve.

[0035] Aspect 27 generally relates to a system according to any of the preceding aspects, wherein the inlet valve includes a check valve.

[0036] Aspect 28 generally relates to a system according to any of the preceding aspects, wherein the inlet valve is a check valve.

[0037] Aspect 29 generally relates to a system according to any of the preceding aspects, wherein the inlet valve is a duckbill valve.

[0038] Aspect 30 generally relates to a system according to any of the preceding aspects, wherein an inlet valve is disposed in a reservoir.

[0039] Aspect 31 generally relates to a system according to any of the preceding aspects, wherein an inlet valve is configured to seal a reservoir chamber.

[0040] Aspect 32 generally relates to a system according to any of the preceding aspects, wherein the pump defines a pump chamber.

[0041] Aspect 33 generally relates to a system according to any of the preceding aspects, wherein the pump has a piston.

[0042] Aspect 34 generally relates to a system according to any of the preceding aspects, wherein a piston is disposed in a pump chamber.

[0043] Aspect 35 generally relates to a system according to any of the preceding aspects, wherein a piston is configured to pump fluid.

[0044] Aspect 36 generally relates to a system according to any of the preceding aspects, wherein the pump has an outlet valve.

[0045] Aspect 37 generally relates to a system according to any of the preceding aspects, wherein an outlet valve is disposed along the pump chamber.

[0046] Aspect 38 generally relates to a system according to any of the preceding aspects, wherein the outlet valve is configured to seal the pump chamber.

[0047] Aspect 39 generally relates to a system according to any of the preceding aspects, wherein the outlet valve includes a check valve.

[0048] Aspect 40 generally relates to a system according to any of the preceding aspects, wherein the outlet valve is a check valve.

[0049] Aspect 41 generally relates to a system according to any of the preceding aspects, wherein the outlet valve comprises one or more valve components.

[0050] Aspect 42 generally relates to a system according to any of the preceding aspects, wherein the valve component is spherical.

[0051] Aspect 43 generally relates to a system according to any of the preceding aspects, wherein the outlet valve includes a valve seat.

[0052] Aspect 44 generally relates to a system according to any of the preceding aspects, wherein the dispenser includes a nozzle.

[0053] Aspect 45 generally relates to a system according to any of the preceding aspects, wherein the nozzle is located on the pump.

[0054] Aspect 46 generally relates to a system according to any of the preceding aspects, wherein the nozzle defines a nozzle opening.

[0055] Aspect 47 generally relates to a system according to any of the preceding aspects, wherein the nozzle opening is configured to discharge fluid from a pump.

[0056] Aspect 48 generally relates to a system according to any of the preceding aspects, wherein the distributor includes a travel limiter.

[0057] Aspect 49 generally relates to a system according to any of the preceding aspects, wherein a stroke limiter is disposed between a reservoir and a pump.

[0058] Aspect 50 generally relates to a system according to any of the preceding aspects, wherein a stroke limiter is disposed on the pump.

[0059] Aspect 51 generally relates to a system according to any of the preceding aspects, wherein a travel limiter is positioned to contact a reservoir upon actuation to limit the travel length of the reservoir.

[0060] Aspect 52 generally relates to a system according to any of the preceding aspects, wherein the stroke limiter is shortened to increase the volume of the dispensed fluid.

[0061] Aspect 53 generally relates to a system according to any of the preceding aspects, wherein the stroke limiter is lengthened to reduce the volume of the dispensed fluid.

[0062] Aspect 54 generally relates to a system according to any of the preceding aspects, wherein the valve seat of the outlet valve is raised to increase the volume of fluid drawn back from the nozzle.

[0063] Aspect 55 generally relates to a system according to any of the preceding aspects, wherein a valve seat has a length corresponding to the volume of fluid between the outlet valve and the nozzle opening, in order to delay the sealing of the outlet valve.

[0064] Aspect 56 generally relates to a system according to any of the preceding aspects, wherein the delay allows the volume of fluid between the outlet valve and the nozzle opening to be drawn back into the outlet valve during the return stroke of the pump.

[0065] Aspect 57 generally relates to a system according to any of the preceding aspects, wherein the length of the valve seat is related to the length of the stroke limiter to achieve a comparable fluid distribution volume.

[0066] Aspect 58 generally relates to a system according to any of the preceding aspects, wherein the pump includes a discharge seal.

[0067] Aspect 59 generally relates to a system according to any of the preceding aspects, wherein a discharge seal is disposed between a valve seat and a piston.

[0068] Aspect 60 generally relates to a system according to any of the preceding aspects, wherein the discharge seal is lengthened to reduce the volume of the dispensed fluid.

[0069] Aspect 61 generally relates to a system according to any of the preceding aspects, wherein the pump includes a spacer disposed within a discharge seal.

[0070] Aspect 62 generally relates to a system according to any of the preceding aspects, wherein a spacer rests against a valve seat.

[0071] Aspect 63 generally relates to a system according to any of the preceding aspects, wherein the spacer is configured to reduce the volume of the dispensed fluid.

[0072] Aspect 64 generally relates to systems described in any of the preceding aspects, which include sensors.

[0073] Aspect 65 generally relates to a system according to any of the preceding aspects, wherein a sensor is configured to sense droplets of fluid dispensed from a dispenser.

[0074] Aspect 66 generally relates to a system according to any of the preceding aspects, wherein a sensor is positioned near the nozzle opening, and a droplet is able to drip through the sensor and onto a glass slide.

[0075] Aspect 67 generally relates to a system according to any of the preceding aspects, wherein the sensor is a dual-light curtain sensor.

[0076] Aspect 68 generally relates to a system according to any of the preceding aspects, wherein a sensor is configured to measure the properties of droplets of a fluid.

[0077] Aspect 69 generally relates to a system according to any of the preceding aspects, wherein a sensor is configured to measure the volume of a droplet.

[0078] Aspect 70 generally relates to a system according to any of the preceding aspects, wherein a sensor is configured to measure the velocity of a droplet.

[0079] Aspect 71 generally relates to a system according to any of the preceding aspects, wherein a sensor is configured to measure the acceleration of a droplet.

[0080] Aspect 72 generally relates to a system according to any of the preceding aspects, wherein the sensor includes a transmitter.

[0081] Aspect 73 generally relates to a system according to any of the preceding aspects, wherein the sensor includes a receiver.

[0082] Aspect 74 generally relates to a system according to any of the preceding aspects, wherein the transmitter and receiver are positioned in a relative manner, and wherein a droplet falls between the transmitter and the receiver.

[0083] Aspect 75 generally relates to a system according to any of the preceding aspects, wherein the sensor includes an entrance light curtain.

[0084] Aspect 76 generally relates to a system according to any of the preceding aspects, wherein the sensor includes an exit light curtain.

[0085] Aspect 77 generally relates to a system according to any of the preceding aspects, wherein the transmitters and receivers of the entrance light curtain and the exit light curtain are arranged in a relative manner to minimize crosstalk.

[0086] Aspect 78 generally relates to a system according to any of the preceding aspects, wherein a sensor is operatively coupled to a controller.

[0087] Aspect 79 generally relates to a system according to any of the preceding aspects, which includes an actuator.

[0088] Aspect 80 generally relates to a system according to any of the preceding aspects, wherein the actuator is communicatively coupled to the controller.

[0089] Aspect 81 generally relates to a system according to any of the preceding aspects, wherein the actuator includes a motor.

[0090] Aspect 82 generally relates to a system according to any of the preceding aspects, wherein the actuator includes an arm.

[0091] Aspect 83 generally relates to a system according to any of the preceding aspects, wherein an arm is configured to actuate a distributor.

[0092] Aspect 84 generally relates to a system according to any of the preceding aspects, wherein the actuator includes a stepper motor.

[0093] Aspect 85 generally relates to a system according to any of the preceding aspects, wherein an arm is coupled to a stepper motor.

[0094] Aspect 86 generally relates to a system according to any of the preceding aspects, wherein the actuator is configured to actuate a distributor to distribute fluid.

[0095] Aspect 87 generally relates to a system according to any of the preceding aspects, wherein the actuator is configured to actuate the distributor with different stroke lengths.

[0096] Aspect 88 generally relates to a system according to any of the preceding aspects, wherein a stepper motor is configured to actuate a distributor with multiple different stroke lengths.

[0097] Aspect 89 generally relates to a system according to any of the preceding aspects, wherein a controller is configured to adjust the operation of an actuator based on the characteristics of a droplet sensed by a sensor.

[0098] Aspect 90 generally relates to a system according to any of the preceding aspects, wherein the controller is configured to adjust the stroke length of the actuator based on the volume of the droplet sensed by a sensor.

[0099] Aspect 91 generally relates to a system according to any of the preceding aspects, wherein the controller is configured to shorten the stroke length of the actuator when the volume of the droplet sensed by the sensor is too large.

[0100] Aspect 92 generally relates to a system according to any of the preceding aspects, wherein the controller is configured to increase the stroke length of the actuator when the volume of the droplet sensed by the sensor is too small.

[0101] Aspect 93 generally relates to a system according to any of the preceding aspects, wherein the dispenser includes a syringe.

[0102] Aspect 94 generally relates to a system according to any of the preceding aspects, wherein the dispenser includes a dispenser clamp that holds the syringe.

[0103] Aspect 95 generally relates to a system according to any of the preceding aspects, wherein the dispenser clamp includes a clamp body and one or more clamping arms extending from the clamp body to clamp onto the syringe.

[0104] Aspect 96 generally relates to a system according to any of the preceding aspects, wherein the dispenser includes a syringe adapter that supports the syringe.

[0105] Aspect 97 generally relates to a system according to any of the preceding aspects, wherein the syringe adapter includes an insert that defines a syringe opening for receiving a syringe.

[0106] Aspect 98 generally relates to a system according to any of the preceding aspects, wherein the insert is made of foam.

[0107] Aspect 99 generally relates to a system according to any of the preceding aspects, which includes a turntable.

[0108] Aspect 100 generally relates to a system according to any of the preceding aspects, wherein the distributor includes a turntable adapter.

[0109] Aspect 101 generally relates to a system according to any of the preceding aspects, wherein the insert is disposed inside the turntable adapter.

[0110] Aspect 102 generally relates to a system according to any of the preceding aspects, wherein a turntable adapter is configured to be coupled to a turntable.

[0111] Aspect 103 generally relates to a system according to any of the preceding aspects, wherein the turntable adapter includes a clamp arm configured to clamp onto the turntable.

[0112] Aspect 104 generally relates to a system according to any of the preceding aspects, wherein the turntable adapter includes a retaining tab configured to hold the turntable adapter on the turntable.

[0113] Aspect 105 involves a general approach.

[0114] Aspect 106 generally relates to the method according to any of the preceding aspects, which includes dispensing a first droplet by actuating a dispenser to a first stroke length using an actuator.

[0115] Aspect 107 generally relates to the method according to any of the preceding aspects, which includes using a sensor to sense a first characteristic of the first droplet.

[0116] Aspect 108 generally relates to the method according to any of the preceding aspects, which includes using a controller to determine a correction factor based on a first characteristic.

[0117] Aspect 109 generally relates to the method according to any of the preceding aspects, which includes using a controller to determine a second stroke length based on a correction factor.

[0118] Aspect 110 generally relates to the method according to any prior aspect, which includes dispensing a second droplet by actuating a dispenser to a second stroke length using an actuator.

[0119] Aspect 111 generally relates to the method described according to any of the preceding aspects, wherein the first stroke length and the second stroke length are different.

[0120] Aspect 112 generally relates to the method according to any of the preceding aspects, wherein a first characteristic of the first droplet is the volume of the first droplet.

[0121] Aspect 113 generally relates to the method described according to any of the preceding aspects, which includes using a controller to detect a volume exceeding a limit.

[0122] Aspect 114 generally relates to the method according to any of the preceding aspects, which includes making the second stroke length shorter than the first stroke length in response to the detection that the volume is higher than a limit.

[0123] Aspect 115 generally relates to the method described according to any of the preceding aspects, which includes using a controller to detect that the volume is below a limit.

[0124] Aspect 116 generally relates to the method according to any of the preceding aspects, which includes making the second stroke length longer than the first stroke length in response to the detection that the volume is below a limit.

[0125] Further forms, objects, features, aspects, benefits, advantages, and embodiments of the invention will become apparent from the detailed description and accompanying drawings provided herein. Attached Figure Description

[0126] Figure 1 is a block diagram of a distributor system with actuators according to an example.

[0127] Figure 2 is an enlarged view of the system in Figure 1.

[0128] Figure 3 is a partial cross-sectional view of an example dispenser that can be used to distribute smaller distribution volumes in the system of Figure 1.

[0129] Figure 4 is a perspective view of the droplet sensor used in the system of Figure 1.

[0130] Figure 5 is a graph showing the sources of fluid loss in a conventional distributor.

[0131] Figure 6 is a graph showing the experimental results, demonstrating the precise control using multiple types of reagents.

[0132] Figure 7 is a graph illustrating different amounts of fluid distribution from experiments using the stepper motor control technique described herein.

[0133] Figure 8 is a graph illustrating the results of another experiment using the stepper motor control method described herein.

[0134] Figure 9 is a graph illustrating the results from another experiment in which the actuator's stroke extension characteristics were altered.

[0135] Figure 10 is a top view of the slides produced by several staining tests.

[0136] Figure 11 is an enlarged cross-sectional view of the distributor in Figure 1.

[0137] Figure 12 is a side view of a distributor that can be used in the system of Figure 1.

[0138] Figure 13 is a cross-sectional view of the dispenser in Figure 12.

[0139] Figure 14 is an enlarged cross-sectional view of the pump chamber in the distributor of Figure 12.

[0140] Figure 15 is a perspective view of the travel limiter used in the distributor of Figure 12.

[0141] Figure 16 is a top view of the travel limiter shown in Figure 15.

[0142] Figure 17 is a cross-sectional view of the travel limiter taken along line 17-17 in Figure 16.

[0143] Figure 18 is an enlarged cross-sectional view of the distributor in Figure 12, showing the stroke length of the distributor.

[0144] Figure 19 is an enlarged cross-sectional view of the pump chamber in the distributor of Figure 12.

[0145] Figure 20 is a top view of the spacer used in the distributor of Figure 12.

[0146] Figure 21 is a side view of the spacer in Figure 20.

[0147] Figure 22 is a side-by-side comparison view of the chamber height in the distributor of Figure 1 and the cross-section of the pump chamber in the distributor of Figure 12.

[0148] Figure 23 is a side view of an example syringe dispenser system that can be used in the system of Figure 1.

[0149] Figure 24 is a perspective view of another example of a syringe dispenser system that can be used in the system of Figure 1.

[0150] Detailed description of the selected implementation plan To facilitate understanding of the principles of the invention, reference will now be made to the embodiments shown in the accompanying drawings, and they will be described using specific language. However, it should be understood that the scope of the invention is not therefore limited. Any changes and further modifications to the described embodiments, as well as any further application of the principles of the invention as described herein, are expected by those skilled in the art to which this invention pertains. One embodiment of the invention is shown in detail, although it will be apparent to those skilled in the art that some features unrelated to the invention may not be shown for clarity.

[0151] The reference numerals in the following description have been organized to help the reader quickly identify the figures that first show various components. In particular, the figure in which an element first appears is typically indicated by the leftmost numeral in the corresponding reference numeral. For example, an element identified by the “100” series of reference numerals may first appear in Figure 1, an element identified by the “200” series of reference numerals may first appear in Figure 2, and so on.

[0152] Figure 1 illustrates a dispenser system 100 according to an example. As shown, system 100 includes an actuator 105, a dispenser 110 coupled to actuator 105, a droplet sensor 115, and a controller 120 operatively coupled to actuator 105 and droplet sensor 115. Through controller 120, actuator 105 is configured to actuate dispenser 110 to dispense reagent in the form of liquid droplets 122 onto a glass slide 125. Droplet sensor 115 is configured to sense droplets 122 when dispensed onto glass slide 125. While system 100 will be described as dispensing liquid reagents, system 100 is configured to displace other types of fluids, such as fluids in liquid and / or gaseous form.

[0153] Distributor system 100 is designed and configured to allow precise and fine control of the downward pressure of distributor 110 (e.g., stroke length, speed, and / or delay). Continuing to refer to Figure 1, actuator 105 includes motor 130 and arm 135 actuated by motor 130. To provide precise distribution control, motor 130 is a stepper motor 137. Stepper motor 137 allows for precise control of the actuation of arm 135. In some examples, stepper motor 137 controls the actuation of arm 135 without the need for additional sensors. It should be appreciated that stepper motor 137 is configured as an electro-linear actuator, translating internal discrete angular steps into external linear motion. In some cases, a series of electrical pulses can be applied to stepper motor 137 to control the angular / linear movement and / or torque applied by stepper motor 137. Typically, stepper motor 137 includes a microcontroller or stepper motor controller that activates coils in the stator of stepper motor 137 in an appropriate sequence to rotate the rotor and actuate it linearly at a desired speed and / or torque, and to rotate and actuate it to an appropriate position. In one version, controller 120 indirectly controls stepper motor 137 via stepper motor controller, but in other examples, controller 120 directly controls stepper motor 137 by applying power directly to the coils of the stator (i.e., without stepper motor controller). In other examples, sensors may be used by actuator 105 and / or controller 120 to monitor the stroke length, position, speed, acceleration, timing, and / or other characteristics of arm 135 during operation. For example, in one example, motor 130 may include a resolver that measures the angular position (or linear position) of the rotor, speed and / or rotational speed, and / or the linear position of the actuation shaft of motor 130.

[0154] In one particular example, actuator 105 is a Zaber NA electric linear actuator (e.g., part number NA11B30-T4A), but other types of actuators can be used. In this example, arm 135 is coupled to motor 130 to extend and retract from motor 130 in a linear motion. Motor 130 and arm 135 of actuator 105 can be mechanically coupled to each other in other ways. For example, a linkage arrangement can be used. In one example, arm 135 is coupled to motor 130 via a crankshaft. In another example, one or more gears in a gear train couple motor 130 to arm 135. Gear trains can be used to enhance control over the stroke length of arm 135 to provide finer control. Gear drives can also be used to adjust the applied torque from motor 130 so that the force applied by arm 135 to distributor 110 can be reduced or increased. Gear drives can also be used to adjust the actuation speed. In one variation, a gear train connects motor 130 to stepper motor 137. In another variation, motor 130 and arm 135 are directly connected together without any intermediate mechanical devices or structures.

[0155] Furthermore, the use of stepper motor 137 allows for precise control of the position, timing, speed, and acceleration of arm 135, which in turn facilitates tight and consistent control of the volume of reagent droplets 122 dispensed by dispenser 110. It has been found that partial stroke actuation requires micro-actuation step lengths via stepper motor 137, speed modulation / ramp, and delayed fine-tuning at the bottom of the stroke to achieve the reproducible fluid motion required for droplet dispensing. Studies have revealed that limited fluid acceleration may exist due to motor speed limitations during dispensing and the area of ​​the nozzle opening in dispenser 110. As will be explained below, it has also been found that mechanical stroke limitations of the piston and the distance of the bottom seal in dispenser 110 can also alter the dispensing volume of each dispenser, but these characteristics do not allow for dynamic variation of the dispensing volume. In system 100 of Figure 1, the dispensing volume from dispenser 110 can be achieved by precisely controlling the stroke length of piston movement by replacing pneumatic hammer actuation with discrete motor steps of stepper motor 137 for downward pressure. The stepper motor 137 enables higher positioning accuracy and partial travel.

[0156] In the example shown, the droplet sensor 115 is in the form of a dual-light-curtain sensor that senses the volume of droplet 122. As shown in FIG1, the droplet sensor 115 includes a first or inlet light curtain 140 and a second or outlet light curtain 142. The inlet light curtain 140 is positioned proximal to the dispenser 110, and the outlet light curtain 142 is positioned proximal to the slide 125. The inlet light curtain 140 and the outlet light curtain 142 each include an emitter 145 and a receiver 150 positioned in a relative manner, such that droplet 122 of reagent 122 falls between the emitter 145 and the receiver 150 for both the inlet light curtain 140 and the outlet light curtain 142. It can be seen that the emitter 145 and the receiver 150 for the inlet light curtain 140 and the outlet light curtain 142 are arranged alternately (i.e., on opposite sides) to avoid crosstalk interference. The inlet light curtain 140 and outlet light curtain 142 of the droplet sensor 115 are communicatively or operatively coupled to the controller 120, such as via wired and / or wireless connections.

[0157] The controller 120 shown in Figure 1 includes a processor 155 and a memory 160 operatively coupled to the processor 155. For clarity, the controller 120 in Figure 1 illustrates a simplified form of the controller 120. It should be appreciated that the controller 120 in operation includes other components such as input / output devices, communication buses, and / or network interfaces. Again, the controller 120 is operatively coupled to the actuator 105 and the droplet sensor 115. The controller 120 is capable of precisely controlling the volume of the reagent droplet 122 applied to the slide 125 by setting and controlling the stroke length, timing, and speed of the arm 135 via the stepper motor 137. Through the droplet sensor 115, the controller 120 is capable of using feedback control to control the volume of the reagent droplet 122 applied to the slide 125 and / or to take other corrective measures. For example, if the processor 155 in controller 120 detects that the volume of the most recently dispensed droplet 122, sensed by droplet sensor 115, is trending below the expected range, controller 120 instructs stepper motor 137 to extend its stroke length when dispensing the next reagent droplet 122 from dispenser 110. Conversely, if controller 120 senses that the droplet volume is too large, the processor 155 of controller 120 may instruct stepper motor 137 to shorten the stroke length of arm 135. Other types of correction measures may be taken. For example, in some variations, controller 120 may issue an alarm or alert when the droplet volume exceeds a predetermined or dynamically determined control limit. In most practical applications, a droplet is only detected after the actuation motion is complete. Any corrections are then made during subsequent dispensing activities. For example, droplet sensor 115 may monitor the initial performance of dispenser 110 during dispensing of dispenser 110. The controller 120 determines one or more calibration settings for the dispenser 110 via the processor 155, and then stores the resulting calibration settings, along with the individual identifier (or ID) of the dispenser 110, in the controller 120's memory 160. In subsequent dispensing for the staining reaction, the individual calibration settings for the dispenser 110 are then applied during actuation by the actuator 105. Subsequently, the droplet sensor 115 continues to monitor the dispensing process and check for errors.

[0158] Referring to Figure 2, dispenser 110 includes a reservoir 205 and a pump 210. The reservoir is configured to store a fluid 207 to be dispensed, such as a liquid reagent, and the pump is configured to pump or dispense the fluid 207, such as in the form of droplets 122, from a nozzle 215. The reservoir 205 is configured to reciprocate in a telescoping manner relative to the pump 210 to pump fluid droplets 122 from the nozzle 215. In one embodiment, the reservoir 205 and pump 210 are made of plastic, but the reservoir 205 and / or pump 210 may be made of different materials such as glass and metal. At the proximal end of the arm 135 of actuator 105, the reservoir 205 has a cap 220. In the example shown, the cap 220 has a flap 225 to facilitate refilling of the reservoir 205, but in other examples, the cap 220 lacks a flap 225. Actuator 105 engages cap 220 via arm 135 to press down reservoir 205 relative to pump 210 in order to pump fluid 207.

[0159] As can be seen in the depicted example, dispenser 110 is mounted on a turntable 230, which facilitates the dispensing of different fluids 207 via different dispensers 110. The turntable 230 defines a dispenser cavity 235 in which the dispenser 110 is received. The turntable 230 defines one or more clamping recesses 240 along the dispenser cavity 235, which are configured to secure the dispenser 110 to the turntable 230. As shown in FIG2, the dispenser 110 is clamped via clamping arms 250 into clamping slots 245 defined in the radial outer wall 247 of the turntable 230. In one embodiment, the clamping arms 250 are configured to releasably secure the dispenser 110 to the turntable 230. For example, a user can press down on the clamping arms 250 to release or de-clamp the dispenser 110 from the turntable 230. At the radial inner wall 252, the turntable 230 defines a retaining groove 255 in which the retaining tab of the dispenser 110 is received to secure the dispenser 110 to the turntable 230.

[0160] As previously mentioned, the dispensing volume in the prior art system was entirely limited by the permissible internal stroke length of the piston in the dispenser. The dispensing volume, in turn, depended on the tolerances of the plastic components of the pump chamber and the piston in the dispenser. Precise control provided by the stepper motor 137 facilitates fine or discrete control of the downward pressure of the dispenser 110 during reagent dispensing. For example, the stepper motor 137 allows for fine control of the stroke length, speed, and delay during reagent dispensing. Utilizing this capability, one form of dispenser 110 has been improved to allow for a wider range of dispensing actions, such as a wider range of reagent volume dispensing and the types of reagents that can be dispensed using the same type of dispenser 110. Some of these improvements will be discussed with reference to Figure 3.

[0161] Referring to Figure 3, reservoir 205 defines a reservoir chamber 305 in which fluid 207 is stored. Pump 210 has a pump body 307 defining a pump chamber 310. Pump chamber 310 is fluidly coupled to reservoir chamber 305 to receive fluid 207 from reservoir chamber 305. At the end of reservoir chamber 305 near pump 210, reservoir 205 has an inlet valve 312 that selectively seals reservoir chamber 305. Along the fluid path between reservoir chamber 305 and pump chamber 310, inlet valve 312 selectively seals reservoir chamber 305 by acting as a check valve. In one example, inlet valve 312 is a duckbill valve, but other types of one-way fluid valves may be used in other examples. Along the pump chamber 310, the pump 210 has a piston 315 with a head 317 to facilitate pumping fluid 207. In one version, the piston 315 has one or more orifices to facilitate the flow of fluid 207 around the piston 315, but in other versions, the piston 315 lacks orifices. The pump 210 also has an outlet valve 320, which acts as a check valve to selectively seal the pump chamber 310. In one variant, the outlet valve 320 is a ball check valve, but other types of check valves may be used in other examples. It can be seen that the reservoir chamber 305 and the outlet valve 320 are located at opposite ends along the fluid path. Inside the pump chamber 310, the piston 315 is positioned between the inlet valve 312 and the outlet valve 320. At the end of the nozzle 215, the pump 210 has a nozzle opening 325 from which fluid 207 is dispensed in the form of one or more droplets 122 (FIG. 1).

[0162] In the depicted embodiment, a portion of the reservoir 205 is received within the pump 210, allowing the reservoir 205 to move reciprocally or telescopically relative to the pump 210. The dispenser 110 has a return spring 330 disposed between the reservoir 205 and the pump 210. The return spring 330 is biased to push or extend the reservoir 205 away from the pump 210. During pumping, the arm 135 of the stepper motor 137 pushes the reservoir 205 toward the pump 210, thereby compressing the return spring 330. After the arm 135 of the actuator 105 releases pressure from the cap 220 of the pump 210, the return spring 330 pushes the reservoir 205 away from the pump 210, bringing it to an extended state.

[0163] To limit the stroke length of the reservoir 205 relative to the pump 210 when the actuator 105 presses down on the reservoir 205, the pump 210 has at least one stroke limiter 335, which is positioned to stop or limit the travel of the reservoir 205. When the reservoir 205 reaches its full stroke length, the reservoir 205 engages the stroke limiter 335. By controlling the stroke length, the stroke limiter 335 limits the maximum amount of fluid 207 that can be dispensed in a single stroke. Because the stepper motor 137 is able to accurately control the stroke length or position of the reservoir 205 during pressing down, the actuator 105 is able to accurately control the volume of fluid 207 dispensed over a wide volume range. Because the dispensing volume can be accurately controlled over a wide range, the stroke limiter 335 is shortened compared to conventional dispensers. This allows the dispenser 110 to have a larger maximum dispensing volume. Therefore, in this design, the same dispenser 110 can be used for a wider range of dispensing volumes and applications. In one application, the nozzle opening 325 is sized to allow a maximum dispensing volume of 70 μl during a single dispensing stroke; however, in other examples, the nozzle opening 325 is sized differently to allow different maximum dispensing volumes. Because the stepper motor 137 is capable of precisely controlling the stroke length of the arm 135, in other variations, the dispenser 110 does not include a stroke limiter 335. The stroke limiter 335 is also configured to retain a seal 337 configured to seal against the piston 315.

[0164] In the example shown, the outlet valve 320 includes one or more valve members 340 and a valve seat 345, at least one of the valve members 340 sealing against the valve seat when the outlet valve 320 is closed. Between the piston 315 and the valve seat 345, the outlet valve 320 has a discharge seal 350 having an opening through which fluid 207 flows. In the depicted example, the discharge seal 350 is raised from the valve seat 345. The discharge seal 350 is configured to seal against the head 317 when the piston 315 is in the fully dispensing stroke position. To reduce accidental dripping of fluid 207 from the nozzle 215, the dispenser 110 includes a backflow feature in which all or most of the fluid 207 in the nozzle 215 located between the outlet valve 320 and the nozzle opening 325 is drawn back into the portion of the pump chamber 310 located between the inlet valve 312 and the outlet valve 320. To accommodate the larger maximum volume of fluid 207 that can be dispensed via the shorter stroke limiter 335, the valve seat 345 is designed to be larger to accommodate the larger maximum volume of fluid 207 that can be drawn back from the nozzle 215 during the retraction stroke of the reservoir 205. Because the valve seat 345 is made larger or longer by being positioned further from the nozzle opening 325, the valve member 340 has a greater travel distance to seal against the valve seat 345. This greater travel distance of the valve member 340 delays the closing of the outlet valve 320, which in turn provides more time for more fluid 207 in the nozzle 215 to be drawn back into the portion of the pump chamber 310 located between the piston 315 and the outlet valve 320.

[0165] During dispensing, actuator 105 presses against cap 220 of reservoir 205 via arm 135, which in turn causes reservoir 205 to move or extend toward pump 210. During this dispensing or extending stroke, inlet valve 312 is closed. With inlet valve 312 closed, the movement of reservoir 205 pressurizes fluid 207 in pump chamber 310, and outlet valve 320 opens to allow fluid 207 to flow through outlet valve 320. When outlet valve 320 is in the open position, the pressure of fluid 207 causes valve member 340 to move away from valve seat 345, causing valve member 340 to disengage from valve seat 345. Fluid 207 can then flow through outlet valve 320. Pressurized fluid 207 from pump chamber 310 flows out from nozzle opening 325 to form droplet 122, which is dispensed onto slide 125, as depicted in FIG. 1. During this compression stroke, the return spring 330 is compressed. When the stroke length corresponding to the desired volume of fluid 207 to be dispensed is reached, the controller 120 stops the extension stroke of the arm 135 of the actuator 105.

[0166] In some cases, actuator 105 may remain in the fully extended position for a period of time, but in other cases, controller 120 may immediately begin retracting arm 135 of actuator 105. In some examples, arm 135 retracts rapidly such that when return spring 330 pushes reservoir 205 away from pump 210, 135 is no longer in contact with cap 220 of reservoir 205. In other cases, arm 135 retracts at a slower rate, wherein arm 135 remains in contact with cap 220 during the retraction stroke to control the rate of retraction of reservoir 205. As reservoir 205 retracts from pump 210, piston 315 also retracts in pump chamber 310 to reduce the pressure inside pump chamber 310, which in turn draws fluid 207 from nozzle 215 back into pump chamber 310 through outlet valve 320. The flow of fluid 207 through outlet valve 320 typically draws valve member 340 toward the end of valve seat 345, where valve member 340 seals against valve seat 345. As fluid 207 flows through outlet valve 320, valve member 340 does not immediately seal or come into position with valve seat 345 due to the recessed or elongated nature of valve seat 345. The length of valve seat 345 through which valve member 340 returns to move toward valve seat 345 is typically related to the volume of fluid 207 between outlet valve 320 and nozzle opening 325. In one example, this volume of fluid 207 between outlet valve 320 and nozzle opening 325 is the same as or similar to the maximum volume that distributor 110 can distribute due to stroke limiter 335, but the volume of fluid 207 between outlet valve 320 and nozzle opening 325 may differ from this maximum distribution volume set by stroke limiter 335.

[0167] As the reservoir 205 continues to retract due to the return spring 330, the valve member 340 eventually comes into place or seals with the valve seat 345, preventing the fluid 207 in the nozzle 215 from being drawn back into the pump chamber 310 via the outlet valve 320. With the outlet valve 320 closed, the retraction of the reservoir 205 reduces the pressure inside the pump chamber 310. When the pressure inside the pump chamber 310 between the inlet valve 312 and the outlet valve 320 is lower than the pressure inside the reservoir chamber 305 of the reservoir 205, the inlet valve 312 opens to allow the fluid 207 in the reservoir chamber 305 of the reservoir 205 to be drawn into the pump chamber 310 of the pump 210. This action replenishes the fluid 207 inside the pump chamber 310 of the pump 210. Once the reservoir 205 retracts to its initial position, the process can be repeated, wherein the controller 120 activates the actuator 105 to pressurize the reservoir 205 so as to distribute fluid 207 onto another slide 125 in a similar manner as described above.

[0168] Figure 4 shows perspective views of both sides of the droplet sensor 115. As previously described, the droplet sensor 115 uses dual-sensor light curtain technology to facilitate the differentiation of multiple reagent types. The droplet sensor 115 includes an inlet light curtain 140 and an outlet light curtain 142. The inlet light curtain 140 and the outlet light curtain 142 each include a transmitter 145 and a receiver 150 positioned in a relative manner, such that a droplet 122 of fluid 207 falls between the transmitter 145 and the receiver 150 for both the inlet light curtain 140 and the outlet light curtain 142. As shown in Figure 4, the transmitter 145 and the receiver 150 for the inlet light curtain 140 and the outlet light curtain 142 are arranged alternately (i.e., on opposite sides) to avoid crosstalk interference. When droplet 122 falls between inlet light curtain 140 and outlet light curtain 142, controller 120 can sense the timing, velocity, acceleration and / or volume of droplet 122 via droplet sensor 115.

[0169] Precision actuator 105 allows for fine control of the pressure (stroke length, speed, and delay) of the reservoir 205 in dispenser 110. Inlet light curtain 140 and outlet light curtain 142 facilitate monitoring of droplet 122 and feedback for calibration system 100, ensuring consistent droplet dispensing. Stepper motor 137 facilitates partial stroke actuation of dispenser 110. By combining stepper motor 137 with feedback from droplet sensor 115, controller 120 can fine-tune the actuation of dispenser 110 via stepper motor 137, speed modulation / ramp, and delay at the bottom of the stroke to achieve reproducible fluid dispensing motion required for droplet dispensing.

[0170] System 100 employs a unique calibration method during automated filling, where calibration occurs directly on system 100. Utilizing light curtain technology provided by inlet light curtain 140 and outlet light curtain 142, controller 120 is able to measure droplets 122 of the actually dispensed fluid 207 via droplet sensor 115. Controller 120 uses this feedback signal from droplet sensor 115 to establish a correction factor. As previously mentioned, in most cases, droplets are only detected after the actuation motion has completed. Any corrections are then performed during subsequent dispensing activities. In one version, droplet sensor 115 monitors the initial performance of dispenser 110 during filling. Controller 120 determines one or more correction settings for dispenser 110 via processor 155 and then stores the resulting correction settings, along with the individual identifier (or ID) of dispenser 110, in controller 120's memory 160. In subsequent dispensing for the staining reaction, correction settings for individual dispensers 110 are applied during actuation by actuator 105. For example, if the volume of droplets 122 dispensed during infusion is lower than the desired volume or exceeds a specified limit, controller 120 can apply a correction factor during normal operation, such as during staining, to adjust the dispensing volume. As an example, based on the correction factor, controller 120 can extend the stroke length of arm 135 via stepper motor 137 to increase the dispensing volume of fluid 207. Conversely, controller 120 can decrease the stroke length of arm 135 via stepper motor 137, thereby reducing the volume of droplets 122. Droplet sensor 115 then continues to monitor the dispensing process and check for errors. In other variations, controller 120 is capable of calibrating or compensating for individual volume deviations between dispensers 110.

[0171] Figure 5 illustrates a graph 500 showing the sources of fluid waste in conventional distributor systems. It can be seen that fluid in conventional distributor systems is wasted through losses such as large excess volumes used for filling, losses due to distributor variability, losses from overfilling, and evaporation losses. Again, the system 100 of Figure 1 is able to control and, in some cases, reduce these sources of fluid volume loss or waste.

[0172] The method of calibrated dispensing, implemented by the dispenser system 100 of Figure 1, which controls actuation via actuator 105 and feedback from droplet sensor 115, can potentially save reagents. As can be seen in Figure 5, a significant source of fluid or reagent waste is due to variations between dispensers. Similarly, variations in manufacturing tolerances between dispensers can lead to dispensers with the same design dispensing different volumes of fluid. Figure 6 shows graph 600 from an experiment where system 100 is able to exhibit overall discrimination of less than 5 µl (<5 µl) for multiple reagent types. Furthermore, some assay frameworks and processes (e.g., probe, user titration, and small-volume pools controlled by air knives) can benefit from system 100's ability to dispense smaller amounts of reagent in a controlled manner. For example, dispensers not improved in the manner discussed above with reference to Figure 3 can benefit from using the actuation and feedback system 100 of Figure 1.

[0173] Figure 7 shows a graph 700 illustrating the results of experiments using the motion control techniques described herein. During the experiments, several discrete speed, stroke, and delay settings of actuator 105 were tested. Reasonable droplet distribution variations were achieved with a sample size of 30 (i.e., n = 30), where the sample standard deviation was less than 3 µl (i.e., sd < 3 µl).

[0174] Figure 8 shows graph 800 illustrating the results of another experiment using the variable velocity and motion control method described herein. It can be seen that a wider range of deliverable volumes was achieved by carefully selecting various velocity and ramp settings. However, reliable droplet formation was not achieved in some volume ranges. For example, as can be seen in graph 800 of Figure 8, reliable droplet formation was clearly not achieved in the range of approximately 55–75 µl.

[0175] Figure 9 shows graph 900 illustrating results from another experiment in which the stroke extension characteristics of stepper motor 137 were altered. In this experiment, the speed and acceleration settings of stepper motor 137 were changed. For example, the acceleration / deceleration ramps were changed to the maximum dispensing speed of stepper motor 137. For graph 900, it appears that the ability to regulate volume during droplet 122 formation may be somewhat limited.

[0176] Figure 10 shows slide 1000 obtained from several staining tests. These tests revealed that a specific combination of solutions with a residual volume of 200 µl controlled by the air knife after rinsing allowed for the application of approximately 70 µl of rare reagent at the same nominal antibody concentration. The staining results shown on slide 1000 in Figure 10 are for BCL2 and Ki67, using a mechanically modified dispenser, limited to dispensing 70 µl of rare reagent, with a residual volume controlled by the air knife of 200 µl. The staining results are compared to a standard application of 100 µl of rare reagent, with a nominal residual volume of 270 µl.

[0177] Turning to Figure 11, the volume of fluid 207 that can be dispensed from distributor 110 can be adjusted in several ways. As shown, reservoir 205 in distributor 110 has a stop ridge 1105 configured to contact a stroke limiting edge 1110 on stroke limiter 335. The stop ridge 1105 and stroke limiting edge 1110 limit the extent to which reservoir 205 can reciprocate relative to pump 210 in order to control the stroke length 1115 of pump 210. Controlling the stroke length 1115, in turn, controls the dispensed fluid volume 1120 of fluid 207 that can be discharged by distributor 110 during a single stroke. The dispensed fluid volume 1120 can be further controlled based on the distance between the surface of head 317 and discharge seal 350.

[0178] Figure 12 illustrates a distributor 1200 according to an example, which is configured to pump a different volume of fluid than the distributor 110 of Figure 2 during a single dispensing stroke. As will be described below, distributor 1200 shares many common features with distributor 110 described above with reference to Figure 2. Only distributor 110 of Figure 2 will be described below. Figure 12The differences between dispensers 1200 and 1200 are as follows. Dispenser 1200 operates in the same manner as dispenser 110 described above with respect to FIG. 2 and FIG. 3. Common components and functions will not be described below, but please refer to the preceding discussion. For example, similar to dispenser 110 of FIG. 3, dispenser 1200 includes a reservoir 1205 and a pump 1210 coupled in a reciprocating manner. Referring to FIG. 2 and FIG. 12, dispenser 1200 includes: a clamping arm 250 configured to clamp into a clamping groove 245 of turntable 230; and a retaining tab 1215 configured to be received within the retaining groove 255 of turntable 230 to retain dispenser 1200. In other words, clamping arm 250 and retaining tab 1215 allow dispenser 1200 to be releasably secured to turntable 230 in the same manner as described above with reference to FIG. 2.

[0179] As can be seen from Figure 13, distributor 1200 shares many components with distributor 110 of Figures 2, 3 and 11. For example, to name just a few, distributor 1200 includes a nozzle 215 with a nozzle opening 325, a piston 315 with a head 317, a return spring 330, a valve member 340, a seal 337 and a valve seat 345 of the type described above. Figure 13 Distributor 1200 of Figure 3 and distributor 110 of Figure 13 share other components. For the sake of brevity and clarity, only the differences between distributor 110 of Figure 3 and distributor 1200 of Figure 13 will be described below. In other words, unless explicitly stated otherwise, distributor 110 of Figure 3 and distributor 1200 of Figure 13 generally share all the same components, and distributor 110 of Figure 3 and distributor 1200 of Figure 13 operate in the same manner. Again, please refer to the preceding discussion on the shared components and functions mentioned above.

[0180] In the distributor 1200 of Figure 13, several components have been modified to adjust the volume of fluid 207 dispensed from the distributor 1200. In the example shown, the distributor 1200 has been modified to reduce the volume of fluid 207 dispensed. In a particular example, the distributor 1200 in Figures 12 and 13 is designed to reduce the volume of fluid 207 dispensed during the lower stroke from a nominal value of approximately 96 microliters (96 µl) found in the distributor 110 of Figure 3 to a nominal value of approximately 75 microliters (75 µl) in the distributor 1200 of Figure 13. To achieve this reduced volume in the distributor 1200, the height of the cylinder stop is increased to reduce the stroke length, and a spacer, such as a polypropylene tube, is inserted between the lower discharge seal and the valve seat or ball insert. It should be recognized that in other examples, dispenser 1200 can be modified to increase the volume of fluid 207 dispensed from the dispenser. Dispenser 1200 in FIG. 13 includes a stroke limiter 1305, which has been lengthened to reduce the stroke length; a discharge seal 1310, which has been lengthened to reduce the volume of fluid 207 to be dispensed; and a spacer 1315, which is received within the discharge seal 1310 to help further reduce the volume of fluid dispensed. In the example of FIG. 13, stroke limiter 1305 and discharge seal 1310 are constructed in a similar manner to stroke limiter 335 and discharge seal 350 of dispenser 110 of FIG. 3, but the relative dimensions of the various portions of stroke limiter 1305 and discharge seal 1310 have been modified to adjust the dispensing volume of fluid 207 dispensed from dispenser 1200 of FIG. 13.

[0181] Figure 14 shows an enlarged cross-sectional view of the pump 1210 in the dispenser 1200. It should be understood that the stroke limiter 1305 has been lengthened to reduce the stroke length of the pump 1210. Figure 15 shows a perspective view of the stroke limiter 1305. Referring to Figures 14 and 15, the reservoir 1205 includes a stop ridge 1405 configured to contact the stroke limiting edge 1410 of the stroke limiter 1305 during the dispensing stroke of the pump 1210. The stroke limiter 1305 includes: a body 1415; a spring retainer flange 1420 disposed opposite the stroke limiting edge 1410 at an end of the body 1415; and a seal retainer flange 1425 configured to retain a seal 337 around the piston 315. The travel limiter 1305 has an integral, hollow cylindrical shape to receive the piston 315. A spring retainer flange 1420 extends radially outward from one end of the travel limiter 1305. A body 1415 extends from the spring retainer flange 1420 toward the end where the travel limit edge 1410 is located.

[0182] Figure 16 shows a top view of the travel limiter 1305. Figure 17 shows a cross-sectional view of the travel limiter 1305 taken along line 17-17 in Figure 16. In one form, the travel limiter 1305 in Figure 17 is higher than the travel limiter 335 in the distributor 110 of Figure 3 to reduce the travel length. As can be seen in Figure 17, the travel limiter 1305 has a height 1705 defined between the end face of the travel limit edge 1410 and the spring retainer flange 1420. In the example shown, the height 1705 of the travel limiter 1305 is approximately 12.0 mm, with a tolerance of approximately ± 0.08 mm (0.473 ± 0.003 inches).

[0183] Because the travel limiter 1305 is taller, the travel length of the distributor 1200 is shorter. For example, turning to Figure 18 The stroke length 1805 of the dispenser 1200 is defined between the outer surface of the stop ridge 1405 of the reservoir 1205 and the outer surface of the stroke limiting edge 1410 of the stroke limiter 1305. In one form, the stroke length 1805 has a resulting length of approximately 5.078 mm (0.1999 inches). The resulting shorter stroke length 1805 allows the dispenser 1200 to dispense fluid 207 with a smaller dispensing volume per individual stroke.

[0184] Referring to Figure 19, the distributor 1200 has a pump chamber 1905 defined between the head 317 of the piston 315 and the surface of the discharge seal 1310. As previously described, the pump chamber 1905 is dimensioned to reduce the volume of fluid 207 dispensed from the distributor 1200. Compared to the discharge seal 350 in Figure 3, the discharge seal 1310 in Figure 19 is higher, allowing it to extend further into the pump chamber 1905, thereby reducing the volume of fluid 207 dispensed. In the example shown, the pump chamber 1905 has a generally cylindrical shape, but in other examples, the pump chamber 1905 may be shaped differently. The pump chamber 1905 has a chamber height 1910 defined between the outer surface of the head 317 of the piston 315 and the outer surface of the discharge seal 1310. In one example, the pump chamber 1905 has a chamber height 1910 of approximately 4.935 mm (0.1934 inches). The pump chamber 1905 further has a chamber diameter 1915, which, together with the chamber height 1910, defines the volume of the pump chamber 1905.

[0185] To facilitate the discharge seal 1310 extending further into the pump chamber 1905 to reduce the volume of the dispensing fluid 207, the dispenser 1200 further includes a spacer 1315 received within the discharge seal 1310. Turning to Figures 20 and 21, in one example, the spacer 1315 is in the form of a plastic tube, such as a polypropylene tube. The spacer 1315 defines a thickness 2105. In one example, the thickness 2105 of the spacer 1315 is approximately 1.4 mm (0.054 inches).

[0186] Figure 22 shows a side-by-side comparison of pump 210 of Figure 2 and pump 1210 of Figure 12. Pump 210 of Figure 2 has a pump chamber 310 with a volume of approximately 124.0224 μL. Pump 1210 of Figure 12 has a pump chamber 1905 with a volume of approximately 98.8924 μL. Pump chamber 310 in pump 210 of Figure 2 has a chamber height 2205 of approximately 6.037 mm (0.2483 inches). Pump chamber 1905 in pump 1210 of Figure 12 has a chamber height 1910 of approximately 4.928 mm (0.1940 inches). Because the chamber height 1910 in pump chamber 1905 of Figure 12 is shorter than the chamber height 2205 in pump chamber 310 of Figure 2, pump 1210 of Figure 12 dispenses a smaller amount of fluid during each dispensing stroke. The lower volume from the dispenser allows for greater flexibility in the type and quantity of fluid that can be dispensed from the dispenser 1200 in Figure 12.

[0187] Figure 23 illustrates another example of a syringe dispenser system 2300 that can be used in the system 100 of Figure 1. In the illustrated example, the syringe dispenser system 2300 includes a syringe 2305 and a dispenser clamp 2310 that is clamped to the syringe 2305 to support the syringe 2305 during fluid dispensing from the syringe 2305. The syringe 2305 includes a barrel 2315, a plunger 2320 slidably disposed within the barrel 2315, and a nozzle 2325 for dispensing fluid 207 from the syringe 2305. In one example, the syringe 2305 is in the form of a 1 ml syringe, but in other examples, the syringe 2305 may be of different sizes to dispense more or less fluid. In one form, the nozzle 2325 is in the form of a hollow plastic tube, but in other examples, the nozzle 2325 may be in the form of a metal needle or take other forms. Dispenser clamp 2310 includes clamp body 2330 and one or more clamping arms 2335 extending from clamp body 2330, which are clamped to barrel 2315 of syringe 2305. Referring to Figures 2 and 23, syringe dispenser system 2300 is detachably secured in turntable 230 of system 100. Dispenser clamp 2310 helps to stabilize syringe 2305 within turntable 230. To dispense fluid from nozzle 2325, arm 135 presses against plunger 2320 until an appropriate volume of fluid is dispensed. It should be appreciated that the stroke length of arm 135 can be adjusted to adjust the volume of fluid dispensed from syringe 2305.

[0188] Figure 24 illustrates another example of a syringe dispenser system 2400 that can be incorporated into system 100 of Figure 1. In the example shown, the syringe dispenser system 2400 includes a syringe 2305 supported by a syringe adapter 2405. The syringe adapter 2405 includes an insert 2410 and a turntable adapter 2415 into which the barrel 2315 of the syringe 2305 is inserted. In one form, the insert 2410 is in the form of a foam insert, but in other examples, the insert 2410 may have other forms. The insert 2410 defines a syringe opening 2420 in which the syringe 2305 extends through the syringe adapter 2405. The insert 2410 is received in the turntable adapter 2415, which is configured to secure the syringe 2305 to a turntable 230.

[0189] Referring to Figures 2 and 24, the rotary table 230 has a dispenser cavity 235 and a clamping recess 240. The syringe adapter 2405 includes a clamping arm 250 configured to clamp the syringe adapter 2405 into the clamping recess 240 of the rotary table 230. The rotary table adapter 2415 further includes a retaining tab 1215 of the type shown in Figure 12. The retaining tab 1215 is configured to insert into a retaining groove 255 of the rotary table 230 to retain the rotary table adapter 2415 within the rotary table 230. The rotary table 230 further defines a nozzle opening 2425 through which the nozzle 2325 of the syringe 2305 extends to the other side of the rotary table 230 to allow dispensing of fluid 207 from the syringe 2305. To dispense fluid from the nozzle 2325, the arm 135 presses against the plunger 2320 until an appropriate volume of fluid is dispensed. It should be recognized that the stroke length of arm 135 can be adjusted to regulate the volume dispensed from syringe 2305. Rotary dial 230 can be indexed to allow other dispensers to dispense reagents or other chemicals.

[0190] Glossary The language used in the claims and description has only its simple and general meaning, unless explicitly defined below. The words in these definitions have only their simple and general meaning. Such simple and general meanings include all consistent dictionary definitions in recently published Merriam-Webster and Random House dictionaries. As used in the description and claims, the following definitions apply to these terms identified below and their common variations.

[0191] An "actuator" generally refers to a device that converts energy into motion. In other words, an actuator is a type of transducer that takes one form of energy and converts it into another, such as by converting electrical energy into mechanical motion. Actuators can generally be classified into two types: linear actuators and rotary actuators. Linear actuators produce linear motion, such as in the case of moving a piston rod. Rotary actuators produce rotational motion, such as in the case of the shaft of an electric motor. Some common types of actuators include electric motors, pneumatic cylinders, hydraulic cylinders, solenoids, and piezoelectric actuators, to name just a few.

[0192] A check valve, or one-way valve, generally refers to a device that primarily allows fluid to flow in one direction. Typically, but not always, a check valve has two ports: one for fluid inlet and another for fluid outlet. Check valves can generally be classified into two categories: mechanical check valves and non-mechanical check valves. For mechanical check valves, a mechanical structure (such as a valve disc or spring-loaded disc) prevents fluid from flowing in the opposite direction. Non-mechanical check valves use fluid flow to prevent reverse fluid flow. Some non-limiting examples of check valves include ball check valves, flapper valves, duckbill valves, diaphragm valves, sheet valves, elastomeric check valves, fluid check valves, and piezoelectric check valves, to name just a few.

[0193] A “controller” typically refers to a device that uses mechanical, hydraulic, pneumatic, electronic technology, and / or a microprocessor or computer to monitor and physically alter the operating conditions of a given dynamic system. For example, a controller may be configured to control the behavior of another mechanical and / or electronic device. A controller may include “control circuitry” configured to provide signals or other electrical impulses that can be received and interpreted by the controlled device to instruct how the controlled device should behave. A controller may include a processor for performing calculations to process inputs or outputs. A controller may include memory for storing values ​​to be processed by the processor or for storing the results of previous processing. A controller may also be configured to accept inputs and outputs from a large number of input and output devices for receiving or sending values. A controller may also be a virtual computing platform with an unknown or fluctuating number of physical processors and memory or memory devices. Therefore, a controller may be physically located in one geographic location or physically distributed across several widely dispersed locations, where multiple processors are interconnected via a communication network to operate as a single controller. Multiple controllers or computing devices may be configured to communicate with each other or with other devices via wired or wireless communication links to form a network.

[0194] An "electric motor" generally refers to a motor that converts electrical energy into mechanical energy. Typically, but not always, an electric motor operates by generating rotational force through the interaction between one or more magnetic fields within the motor and the current in the windings. Electric motors can be driven by direct current (DC) power sources, such as from batteries, motor vehicles, and / or rectifiers, or by alternating current (AC) power sources, such as the power grid, inverters, and / or generators. Generators can (but are not always) be mechanically identical to electric motors, but operate in the opposite direction, accepting mechanical energy and converting it into electrical energy.

[0195] "Fluid" generally refers to a substance that does not have a fixed shape. For example, fluids include liquids and / or gases. Typically, fluids are capable of flowing easily, such as air flowing over an aircraft wing, blood flowing through a circulatory system, water flowing through pipes, or oil flowing through an electric motor. In some cases, a fluid refers to a mixture of solids, liquids, and / or gases. For example, a slurry of solids and water, liquid droplets mixed with air, aerated solid particles, mixtures of solids with liquids and gases, and / or other mixtures of different materials can be fluids.

[0196] "Foam" generally refers to materials formed by trapping gas vesicles within a liquid or solid. Solid foams are typically classified as open-cell foams or closed-cell foams. Open-cell foams contain an interconnected network of pores, while closed-cell foams do not. Some closed-cell foams (sometimes called synthetic foams) contain hollow particles or microspheres embedded in a matrix of the material.

[0197] A "gear train" generally refers to a gear system that transmits power from one mechanical component to another. For example, a gear train may include a combination of two or more gears mounted on a rotating shaft to transmit torque and / or power. As a non-limiting example, a gear train may include a planetary gear set.

[0198] "Memory" generally refers to any storage system or device configured to retain data or information. To name just a few examples, each memory may include one or more types of solid-state electronic memory, magnetic memory, or optical memory. As a non-limiting example, each memory may include solid-state electronic random access memory (RAM), sequential access memory (SAM) (such as FIFO or LIFO types), programmable read-only memory (PROM), electrically programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM); optical disc storage (such as DVD or CD ROM); magnetically encoded hard disks, floppy disks, magnetic tape, or magnetic tape cassette media; or any combination of these memory types. Furthermore, each memory may be volatile, non-volatile, or a mixture of volatile and non-volatile types.

[0199] "Electric motor" generally refers to a machine that provides power to a device having moving parts. Electric motors can include rotary motors and linear motors. Electric motors can be driven in a variety of ways, such as by electric, internal combustion, pneumatic, and / or hydraulic power sources. As non-limiting examples, electric motors can include servo motors, pneumatic motors, electric motors, hydraulic motors, steam engines, pneumatic pistons, hydraulic pistons, and / or internal combustion engines.

[0200] An "opening" usually refers to a space or hole through which something can pass.

[0201] A “processor” generally refers to one or more electronic components configured to operate as a single unit, which is configured or programmed to process input to generate output. Alternatively, when in a multi-component form, a processor may have one or more components located remotely relative to other components. The one or more components of each processor may be electronic varieties defining digital circuit systems, analog circuit systems, or both. In one example, each processor is a conventional integrated circuit microprocessor arrangement. The concept of a “processor” is not limited to a single physical logic circuit or circuit package, but includes one or more such circuits or circuit packages that may be contained within or across multiple computers in numerous physical locations. In a virtual computing environment, an unknown number of physical processors may be actively processing data, and this unknown number may also change automatically over time. The concept of a “processor” includes means configured or programmed to perform threshold comparisons, rule comparisons, calculations, or logical operations that apply rules to data to produce logical results (e.g., “true” or “false”). Processing activity may occur on multiple single processors on a single server, on multiple processors in a single server with separate processors, or on multiple processors physically distant from each other in a single computing device.

[0202] A pump is generally a machine that moves fluids (such as gases, liquids, and / or slurries) through mechanical action. Typically, but not always, pumps are manually driven or automatically driven by an energy source such as electricity. Pumps are generally used to move fluids to different locations and / or increase the pressure of fluids. Some common types of pumps include centrifugal pumps, positive displacement pumps, axial flow pumps, and gravity pumps.

[0203] A "rotary transformer" generally refers to a rotary sensor used to measure the degree of rotation, speed, and / or acceleration of a rotary device. In one example, a rotary transformer includes a rotary electrical transformer used to measure the degree of rotation in a motor, generator, and / or transmission. Rotary transformers can include analog or digital electrical devices. Rotary transformers can be bipolar or multipolar. Some other types of rotary transformers include receiver-type rotary transformers and differential-type rotary transformers.

[0204] A "sensor" generally refers to an object whose purpose is to detect events and / or changes in its environment and then provide a corresponding output. Sensors include transducers that provide various types of outputs, such as electrical signals and / or optical signals. As non-limiting examples, sensors may include pressure sensors, ultrasonic sensors, humidity sensors, gas sensors, motion sensors, acceleration sensors, displacement sensors, force sensors, optical sensors, and / or electromagnetic sensors. In some examples, sensors include barcode readers, RFID readers, and / or vision systems.

[0205] A "spring" generally refers to an elastic object that stores mechanical energy. A spring can include an elastic device that can be pressed, stretched, and / or twisted, but returns to its original shape upon release. Springs can be made of resilient or elastic materials, such as metals and / or plastics. Springs can resist or withstand loads in a variety of ways and apply a constant or variable level of force. For example, springs can include tension springs, compression springs, torsion springs, constant springs, and / or variable springs. Springs can take many forms, such as by being a flat spring, a machined spring, and / or a serpentine spring. As a non-limiting example, springs can include various helical springs, pocket springs, Bonnell coils, bias coils, continuous coils, cantilever springs, spiral springs, hairsprings, leaf springs, V-springs, gas springs, leaf springs, torsion springs, rubber bands, spring washers, and / or wave springs, to name just a few.

[0206] A "stepper motor" generally refers to a type of electric motor that rotates in a series of small, discrete angular steps. In one form, a stepper motor is a brushless direct current (DC) motor, dividing a complete rotation into equal discrete step sizes. A stepper motor operates by sequentially exciting a series of coils to attract permanent magnets. Stepper motors are typically configured to move and hold the rotor in one discrete angular step without requiring a position sensor. In one version, the stator of a stepper motor comprises multiple toothed electromagnets arranged around a rotor that is arranged in the form of gear-shaped permanent magnets. A series of input pulses (such as in the form of a square wave) can be used to precisely increment the rotor's rotational position. Stepper motors can be classified into permanent magnet stepper motors, variable reluctance stepper motors, and hybrid synchronous stepper motors.

[0207] A "syringe" generally refers to a reciprocating pump that includes a plunger or piston sealed within a barrel. In conventional designs, a plunger is typically used to pump fluid, but in some cases, a piston within the syringe is used instead. Typically, but not always, the barrel is a hollow cylindrical body in which the plunger or piston is slidably received to enable the reciprocating pumping action. The plunger or piston is tightly fitted within the barrel. In some designs, pushing the plunger creates pressure in the fluid contained within the barrel to eject or otherwise expel fluid from the barrel through a needle or nozzle. Conversely, pulling the plunger reduces the pressure inside the barrel to draw fluid into the barrel via the needle or nozzle. In some cases, the syringe may include a needle hub to which the needle is attached. In some versions, the needle hub includes a mechanism for securing the needle, such as a Luer lock connector. In other cases, the syringe includes a nozzle instead of a needle. The nozzle is typically used to dispense liquid without piercing skin or other materials. In several versions, the needle or nozzle extends from the end of the barrel opposite the plunger. Syringes can be made from a variety of materials, including but not limited to plastics, glass, rubber, and / or metals. Some common types of syringes include hypodermic syringes, oral syringes, insulin syringes, and flushing syringes, to name just a few. Syringes can be used in a wide range of applications, such as medical, scientific, and / or industrial uses.

[0208] It should be noted that the singular forms “a / an”, “the”, etc., used in the description and / or claims include the plural forms unless otherwise explicitly discussed. For example, if the specification and / or claims refer to “a device” or “the device”, it includes one or more such devices.

[0209] It should be noted that directional terms such as “upward,” “downward,” “top,” “bottom,” “lateral,” “longitudinal,” “radial,” “circumferential,” “horizontal,” and “vertical” are used herein merely for the convenience of the reader in order to help the reader understand the illustrated embodiments, and the use of these directional terms in any way is not intended to limit the described, illustrated, and / or claimed features to a particular direction and / or orientation.

[0210] Although the invention has been illustrated and described in detail in the accompanying drawings and the foregoing description, it should be considered illustrative in nature and not restrictive. It should be understood that only preferred embodiments have been shown and described, and protection is intended for all changes, equivalents, and modifications within the spirit and scope of the invention as defined by the following claims. All publications, patents, and patent applications referenced in this specification are incorporated herein by reference, as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein.

[0211] Figure Labels

Claims

1. A system comprising: A distributor configured to dispense fluid; An actuator configured to actuate the dispenser to dispense the fluid; The actuator mentioned above includes a stepper motor; and The stepper motor is configured to actuate the distributor with multiple different stroke lengths.

2. The system according to claim 1, further comprising: A sensor configured to sense droplets of the fluid dispensed from the dispenser; The sensor is configured to measure the properties of the droplets of the fluid; and A controller configured to adjust the operation of the actuator based on the characteristics of the droplet sensed by the sensor.

3. The system according to claim 2, wherein: The sensor is configured to measure the volume of the droplet; and The controller is configured to adjust the stroke length of the actuator based on the volume of the droplet sensed by the sensor.

4. The system according to claim 1, wherein: The distributor includes a storage unit; The reservoir is configured to store the fluid; The dispenser includes a pump; The reservoir and the pump are coupled in a reciprocating manner; The distributor includes a travel limiter; and The travel limiter is positioned to contact the reservoir upon actuation to limit the travel length of the reservoir.

5. The system of claim 4, wherein the stroke limiter is shortened to increase the volume of the dispensed fluid.

6. The system according to claim 4, wherein: The dispenser includes a nozzle; The pump has an outlet valve; The outlet valve includes a valve seat; and The valve seat of the outlet valve is raised to increase the volume of fluid drawn back from the nozzle.

7. The system according to claim 6, wherein: The nozzle defines a nozzle opening; and The valve seat has a length corresponding to the volume of fluid between the outlet valve and the nozzle opening, in order to delay the sealing of the outlet valve.

8. The system of claim 7, wherein the length of the valve seat is related to the length of the stroke limiter to achieve a corresponding fluid distribution volume.

9. The system of claim 4, wherein the stroke limiter is lengthened to reduce the volume of the dispensed fluid.

10. The system according to claim 4, wherein: The pump has an outlet valve; The outlet valve includes a valve seat; The pump has a piston; The pump includes a discharge seal; and The discharge seal is disposed between the valve seat and the piston.

11. The system of claim 10, wherein the discharge seal is lengthened to reduce the volume of the dispensed fluid.

12. The system according to claim 11, wherein: The pump includes a spacer disposed inside the discharge seal; and The spacer is configured to reduce the volume of the dispensed fluid.

13. The system of claim 1, wherein the dispenser comprises a syringe.

14. The system according to claim 13, wherein: The dispenser includes a dispenser clamp that holds the syringe; and The dispenser clamp includes a clamp body and one or more clamping arms extending from the clamp body to clamp the syringe.

15. The system according to claim 13, wherein: The dispenser includes a syringe adapter that supports the syringe; and The syringe adapter includes an insert that defines a syringe opening for receiving the syringe.

16. The system of claim 15, further comprising: Turntable; The dispenser includes a turntable adapter; The insert is disposed inside the turntable adapter; and The turntable adapter is configured to be coupled to the turntable.

17. The system of claim 16, wherein: The turntable adapter includes a clamping arm configured to grip the turntable; and The turntable adapter includes a retaining tab configured to hold the turntable adapter on the turntable.

18. A system comprising: A distributor configured to dispense fluid; An actuator configured to actuate the dispenser to dispense the fluid; A sensor configured to sense droplets of the fluid dispensed from the dispenser; The sensor is configured to measure the properties of the droplets of the fluid; and A controller configured to adjust the operation of the actuator based on the characteristics of the droplet sensed by the sensor.

19. The system according to claim 18, wherein: The sensor is configured to measure the volume of the droplet; and The controller is configured to adjust the stroke length of the actuator based on the volume of the droplet sensed by the sensor.

20. The system of claim 19, wherein the controller is configured to shorten the stroke length of the actuator when the volume of the droplet sensed by the sensor is too large.

21. The system of claim 19, wherein the controller is configured to increase the stroke length of the actuator when the volume of the droplet sensed by the sensor is too small.

22. The system of claim 18, wherein the sensor is a dual-light curtain sensor.

23. The system according to claim 22, wherein: The sensor includes a transmitter; The sensor includes a receiver; and The transmitter and the receiver are positioned relative to each other, wherein the droplet falls between the transmitter and the receiver.

24. The system of claim 18, wherein: The actuator includes a stepper motor; The actuator includes an arm; The arm is coupled to the stepper motor; and The arm is configured to actuate the dispenser.

25. A method comprising: The first droplet is dispensed by actuating the dispenser to a first stroke length using an actuator. Use a sensor to sense the first characteristic of the first droplet; The controller is used to determine the correction factor based on the first characteristic; The controller is used to determine the second stroke length based on the correction factor; as well as The second droplet is dispensed by actuating the dispenser to the second stroke length using the actuator.

26. The method of claim 25, further comprising: The first characteristic of the first droplet is the volume of the first droplet; The controller was used to detect that the volume was higher than the limit. as well as In response to the discovery that the volume is higher than the limit, the second stroke length is made shorter than the first stroke length.

27. The method of claim 25, further comprising: The first characteristic of the first droplet is the volume of the first droplet; The controller was used to detect that the volume was below the limit. as well as In response to the discovery that the volume is below the limit, the second stroke length is made longer than the first stroke length.

28. The method of claim 25, wherein the actuator comprises a stepper motor.

29. The method of claim 25, wherein: The distributor includes a storage unit; The dispenser includes a pump; The reservoir and the pump are telescopically coupled; and The dispenser includes a spring disposed between the reservoir and the pump.

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