Automated slide staining apparatus

A slide stainer assembly is disclosed. The slide stainer includes a slide carrier that is configured to carry one or more laboratory slides and a plurality of slide processing stations for processing the slides. A transport member including a plurality of engagement portions is configured for releasably engaging the slide carrier. A drive mechanism is coupled to the transport member. The drive mechanism is configured to move the transport member in a cyclical path such that, in the course of one cycle, the transport member engages a slide carrier docked in a first station, removes the slide carrier from the first station, docks the slide carrier in a second station and returns to the first station to engage another slide carrier.

FIELD OF THE INVENTION

The present invention relates to an apparatus for staining laboratory slides.

BACKGROUND OF THE INVENTION

Laboratories routinely stain biological tissue specimens deposited on laboratory slides for subsequent pathologic examination to detect and/or monitor tissue abnormalities. Automated tissue staining systems allow batch staining of large numbers of slides containing tissue specimens for subsequent examination. In the course of a staining process, the tissue specimens are exposed to a series of well-defined processing steps that ultimately produces a properly stained specimen for examination. Automation of the staining process significantly reduces the time required to stain tissue specimens, reduces the incidence of human error and allows processing parameters to be altered in an efficient manner. Improvements to slide staining systems are continually sought in the interest of reliability, performance, speed and cost.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a slide stainer assembly is disclosed. The slide stainer includes a slide carrier that is configured to carry one or more laboratory slides. A plurality of slide staining and/or slide rinsing stations are provided on the slide stainer. Each station is configured to process the slides of the slide carrier. The slide stainer includes a transport member including a plurality of engagement portions. Each engagement portion is configured for releasably engaging a slide carrier. A drive mechanism is coupled to the transport member. The drive mechanism is configured to move the transport member in a cyclical path such that, in the course of one cycle, the transport member engages a slide carrier docked in a first station, removes the slide carrier from the first station, docks the slide carrier in a second station disengages the first slide and returns to the first station to engage another slide carrier.

According to another aspect of the invention, the slide stainer includes a storage vessel positioned adjacent the second station. The storage vessel is sized for receiving a plurality of slide carriers each including one or more processed laboratory slides. The drive mechanism is configured to move the transport member in a cyclical path such that, in the course of one cycle, (i) the engagement portion of the transport member engages and removes a first slide carrier from the second station, (ii) the extended segment of the transport member translates a second slide carrier that is positioned within the storage vessel to accommodate the first slide carrier, and (iii) positions the first slide carrier in the storage vessel.

DETAILED DESCRIPTION OF THE INVENTION

The invention will next be illustrated with reference to the figures. Such figures are intended to be illustrative rather than limiting and are included herewith to facilitate explanation of the present invention. In the figures, like item numbers refer to like elements throughout. When a plurality of similar elements are present, a single reference numeral may be assigned to the plurality of similar elements with a small letter designation referring to specific elements. When referring to the elements collectively or to a non-specific element, the small letter designation may be omitted.

FIGS. 1-5depicts perspective, front elevation, top plan, right side elevation and partially exploded views, respectively, of slide stainer10according to one exemplary embodiment of the invention. Slide stainer10includes a plurality of slide processing stations12a-12nfor staining, rinsing, or otherwise processing, laboratory slides. Illustrated housing11of slide stainer10includes a substantially rectangular recess13(seeFIG. 5) that is sized to accommodate stations12a-12nand storage vessel16. Storage vessel16is positioned adjacent the right-most station12nin the illustrated embodiment for storing one or more processed slides after laboratory slides are sequentially processed in stations12athrough12n.

Each slide processing station12(hereinafter station12) in the illustrated embodiment includes a vessel that may be filled with either a reagent for staining the slide, or a rinsing medium, such as water, for rinsing the slide. In alternative embodiments, one or more of the stations may be a drying station or other type of station that would be understood by one of skill in the art from the description herein. In the embodiment shown inFIGS. 1-5, station12dis a rinsing station and stations12a-12cand12e-12nare staining stations. It should be understood that any station may be a staining station, a rinsing station or other type of station and slide stainer10is not limited to the particular configuration shown. Moreover, the vessels associated with stations12a-12nmay be removable from housing11of slide stainer10, such that stations12within slide stainer10may be reconfigured to the operator's requirements.

Slide stainer10is configured to sequentially transport one or more slide carrier assemblies20to each station12a-12nand then to storage vessel16under the control of an electronics control unit (ECU)25(described below), for example. Each station12a-12nis configured to receive a single slide carrier assembly20. Each slide carrier assembly20includes slide carrier22and a plurality of laboratory slides24releasably mounted to slide carrier22. A laboratory specimen (not shown) is mounted to each laboratory slide24. Further details of slide carrier assembly20are described with reference toFIGS. 16-18. Three (3) slide carrier assemblies20a,20band20care illustrated in the exemplary embodiment depicted in the figures. It will be understood by those skilled in the art from the description herein that slide stainer10may interface with multiple slide carrier assemblies20.

Illustrated storage vessel16can accommodate four (4) processed slide carrier assemblies20. Those skilled in the art will recognize that storage vessel16may be configured to accommodate any number of slide carrier assemblies20. The ECU25may be configured to maintain an active count of the number of processed slide carrier assemblies20within the storage vessel16. In operation, once three (3) processed slide carrier assemblies20are contained within storage vessel16, ECU25may issue a distinctive audible warning (such as three beeps) alerting the operator to the near-filled condition. After the fourth processed slide carrier assembly20is inserted into storage vessel16, storage vessel16is completely filled with processed slide carrier assemblies. Accordingly, once the fourth processed slide carrier assembly20is inserted into storage vessel16, ECU25may deactivate slide stainer10to prevent further processed slide carrier assemblies from being placed into the filled storage vessel16. Alternatively, a sensor (not shown) may be provided in storage vessel16to sense when it is completely filled with processed slide carrier assemblies20. Such a sensor may send a signal to ECU25of slide stainer10to either warn the operator or deactivate slide stainer10.

FIG. 6depicts a cross-sectional view of staining station12ftaken along the lines6-6ofFIG. 3. Slide carrier assembly20is shown docked in staining station12f(not shown inFIG. 3). Staining station12fgenerally includes vessel14that is filled with a reagent for staining laboratory slides24of slide carrier assembly20. Vessel14may be sized to contain about 50 milliliters of fluid, for example. Slides24of slide carrier assembly20are submerged in the reagent bath.

FIG. 7depicts a cross-sectional view of rinsing station12dtaken along the lines7-7ofFIG. 3. Slide carrier assembly20is shown docked in rinsing station12d(not shown inFIG. 3). Rinsing station12dgenerally includes vessel15filled with liquid (e.g., water) for rinsing laboratory slides24of slide carrier assembly20. Slides24of slide carrier assembly20are at least partially submerged in the water bath. Water (or other rinsing fluid) is delivered into vessel15through fluid dispersion device40that is mounted to the bottom end of vessel15. Fluid dispersion device40is fluidly coupled to inlet port44(seeFIG. 4) of slide stainer10by a fluid supply line46. Inlet port44is coupled to a water source. Although not shown, a valve is coupled to inlet port44for selectively controlling the flow of fluid through fluid supply line46.

Fluid dispersion device40disperses the flow of rinse fluid entering vessel15such that, during rinsing, the flow of rinse fluid is not concentrated in any particular area within vessel15. By dispersing the flow of rinse fluid, all laboratory slides24within vessel15are subject to substantially the same rinse fluid flow. Further details of fluid dispersion devices are disclosed in U.S. Pat. No. 6,585,936 to Shah, which is incorporated by reference herein in its entirety.

Vessel15includes an opening48on its bottom surface for receiving fluid dispersion device40and an opening50on side surface52for draining excess rinse fluid from vessel15. Accordingly, when the fluid level within vessel15reaches opening50, the fluid drains from vessel15through opening50. Although not shown, a drain port is defined in recess13of slide stainer housing11for transporting the excess rinse fluid away. A universal vessel may be used for staining station12fand rinsing station12d. If the same vessel is used in both stations, plugs may be applied over openings48and50when vessel15is used in a staining station.

FIG. 8depicts a front elevation view of a portion of transport member26. Transport member26is provided for sequentially transporting slide carrier assemblies20to adjacent stations12and then to storage vessel16. Transport member26is optionally a flat sheet of material. A plurality of engagement portions28(14shown) are defined on the top surface of transport member26. Each engagement portion28is configured for releasably engaging a single slide carrier22of slide carrier assembly20. Protrusions31(seeFIG. 6B) are formed on the top surface of transport member26opposite each engagement portion28for retaining slide carrier22in position and restricting slide carrier22from sliding along the length of transport member26. Transport member26includes extended segment34which extends to an elevation below the right-most engagement portion28. As described in greater detail with reference toFIG. 9C, extended segment34is sized and shaped for advancing a processed slide carrier assembly20that is positioned within storage vessel16to accommodate an additional processed slide carrier assembly20.

FIGS. 9A-9Fdepict a schematic side elevation view of transport member26advancing slide carrier assemblies20a-20cthrough one cycle. InFIGS. 9A-9Fonly stations12a-12c,12mand12nare shown and only a portion of transport member26is shown for simplicity.

Generally, as depicted inFIGS. 9A-9F, transport member26sequentially transports slide carrier assemblies20to adjacent stations12and then to storage vessel16. Transport member26is moved along path29, as illustrated by broken lines, by a drive mechanism (described below; not explicitly shown inFIGS. 9A-9F) of slide stainer10. The drive mechanism causes pins32to move along their respective paths29. Pins32of the drive mechanism are mounted to transport member26through holes35provided in transport member26(seeFIG. 8). Fasteners (not shown) may be utilized to secure transport member26to pins32. In an exemplary embodiment, pins32simultaneously move along their respective paths29, each of the paths29have the same trajectory, pins32move at the same speed, and, at any time, pins32are positioned at the same locations along their respective paths29. Because pins32are fixed to transport member26, transport member26travels along path29coincident with pins32. Those skilled in the art will recognize that the motion of pins32may vary from that shown and described without departing from the scope or spirit of the invention.

FIG. 9Adepicts a starting position of slide stainer10. In the starting position, slide carrier assembly20ais docked in station12a, slide carrier assembly20bis docked in station12nand slide carrier assembly20cis docked in storage vessel16. Slide carriers22of slide carrier assemblies20aand20bare engaged by engagement portions28of transport member26. Engagement between slide carrier assembly22band transport member26is shown inFIG. 10.

As shown inFIG. 10, engagement portion28of transport member26is releasably positioned within recess33formed in slide carrier22of slide carrier assembly22b. Protrusions31formed on each side of engagement portion28retain slide carrier22in a fixed position and restrict slide carrier22from sliding along the length of transport member26. Releasable engagement between transport member26and slide carrier22enables slides24to be deposited and removed vertically into and out of vessels14and15.

Those skilled in the art will understand from the description herein that various ways exist to releasably mount a slide carrier to a transport member. For example, a protrusion formed in a slide carrier may be engaged within a recess formed in the transport member. Alternatively, slide carrier may be releasably coupled to the transport member by a pin and slot, a fastener, a plug, a surface or any other device known to those skilled in the art. Accordingly, it may be referred to herein that slide carrier10includes means for releasably coupling a slide carrier to the transport member.

Referring back to the configuration shown inFIG. 9A, laboratory slides24of slide carrier assemblies20aand20bare being processed, i.e., rinsed or stained, for example, whereas slide carrier assembly20cis not being processed. Once processing of laboratory slides24of slide carrier assemblies20aand20bis complete, slide stainer10is configured to do the following: (1) transport slide carrier assembly20ato the next station, i.e., station12b, and (2) transport slide carrier assembly20bfrom station12nto storage vessel16. It should be understood that station12nis the final processing station of slide stainer10and once processing of the laboratory slides of a slide carrier assembly is complete, the processed slide carrier assembly is ready for temporary storage in storage vessel16.

Referring now toFIGS. 9A and 9B, the drive mechanism translates pins32in the upward direction along their respective paths29, as depicted by the arrows on paths29, from their location shown inFIG. 9Ato their location shown inFIG. 9B. Translation of pins32causes translation of transport member26and slide carrier assemblies20aand20b. As noted previously, transport member26is fixed to pins32and slide carrier assemblies20aand20bare releasably engaged with transport member26, thus, movement of pins32causes movement of slide carrier assemblies20aand20b. By moving in the upward direction, transport member26removes laboratory slides24of slide carrier assemblies20aand20bfrom stations12aand12n, respectively. As shown inFIG. 9B, extended segment34of transport member26is positioned to bear against slide carrier22of slide carrier assembly20c.

Referring now toFIGS. 9B and 9C, the drive mechanism translates transport member26and slide carrier assemblies20aand20bin a horizontal direction (to the right) from their location shown inFIG. 9Bto their location shown inFIG. 9C. Translating transport member26in a horizontal direction by a pre-determined distance causes extended segment34of transport member26to push slide carrier22of slide carrier assembly20cin a horizontal direction by the same distance. Translating slide carrier assembly20cwithin storage vessel16provides sufficient room to accommodate slide carrier assembly20bwithin storage vessel16.

Referring now toFIGS. 9C and 9D, the drive mechanism translates transport member26and slide carrier assemblies20aand20bin a downward vertical direction from their location shown inFIG. 9Cto their docked location shown inFIG. 9D. InFIG. 9D, slide carrier assembly20ais shown docked in station12bfor processing (e.g., staining or rinsing). Slide carrier assembly20aremains in the position shown inFIG. 9Dfor a time-span of between 2 seconds and 300 seconds, for example, to allow processing of the laboratory slides that are immersed in reagent-filled station12b.

In a docked position the underside surface of carrier20of slide carrier assembly20a(or any slide carrier assembly for that matter) is positioned to bear on the top lip of vessel14. InFIG. 9D, slide carrier assembly20bis shown docked in storage vessel16beside slide carrier assembly20c. Engagement between slide carrier assembly20cand storage vessel16is illustrated inFIG. 11. As shown inFIG. 11, walls60extending from opposite sides of storage vessel16rest on underside surfaces62of slide carrier22of slide carrier assembly20c.

Referring now toFIGS. 9D and 9E, in the motion of transport member26from its position shown inFIG. 9Dto its position shown inFIG. 9E, transport member26disengages from slide carrier assemblies20aand20b. Specifically, inFIG. 9Dengagement portions28of transport member26are engaged with slide carrier assemblies20aand20b. The drive mechanism translates transport member26downward (and to the left) from its location shown inFIG. 9Dto its location shown inFIG. 9E. In its downward movement, engagement portions28of transport member26release from slide carrier assemblies20aand20b. In other words, inFIG. 9Etransport member26is completely detached from slide carrier assemblies20aand20b.

Referring now toFIGS. 9E and 9F, the drive mechanism translates transport member26further to the left and in an upward direction from its location shown inFIG. 9Eto its location shown inFIG. 9F. In its upward movement, engagement portion28of transport member26engages slide carrier assembly20a. Transport member26is positioned in the same location inFIG. 9Fas it is shown inFIG. 9A. Although not shown, it should be understood that in the next cycle of transport member26, slide carrier assembly20ais moved to station12cand slide carrier assemblies20band20care slid to the right within vessel16to accommodate another processed slide carrier assembly (not shown).

Referring generally toFIGS. 9A-9F, transport member26of slide stainer10performs the following steps in the course of one cycle: (1) engages a first slide carrier assembly in a first station (either a staining station or a rinsing station); (2) removes the first slide carrier assembly from the first station; (3) moves a second processed slide carrier assembly that is positioned within the storage vessel16to accommodate another processed slide carrier assembly; (4) positions the first slide carrier assembly in a second station (either a staining station, a rinsing station or the storage vessel) that is adjacent the first station; and (5) returns to the first station to engage another slide carrier assembly.

InFIGS. 9A-9Fonly three slide carrier assemblies20are shown. According to this exemplary embodiment, up to fourteen (14) slide carrier assemblies20may be coupled to transport member26at any time. Additionally, it should be understood that if transport member26includes more than fourteen (14) engagement portions28then transport member26can accommodate more than fourteen (14) slide carrier assemblies20. To transfer a single slide carrier assembly20sequentially between station12aand storage vessel16, drive mechanism would move transport member26through fourteen (14) complete cycles.

FIG. 12depicts drive mechanism30of slide stainer10. According to one exemplary embodiment, drive mechanism30includes motor70that is fixed to housing11. Motor70includes a rotating gear shaft71having gear teeth for driving toothed belt72. Toothed belt72drives two guiding devices79and80. Each guiding device79,80is shown partially cut-away to reveal the engagement between toothed belt72and toothed gear81of each guiding device79and80. As explained in greater detail with reference toFIGS. 13-15, guiding devices79and80are configured to drive transport member26along path29depicted inFIGS. 9A-9F. The flat side of toothed belt72engages roller82. A slot84is provided on housing11for adjusting the position of roller82to adjust the tension applied to toothed belt72.

Optical sensor86is mounted to housing11for activating or deactivating motor70based upon the rotational position of guiding device80. Optical sensor86includes a light source that is positioned on one side of cover88of guiding device80and a light sensor that is positioned on the opposite side of cover88. The outer edge of cover88is positioned between the light source and the light sensor of optical sensor86such that the light sensor does not ordinarily detect the light source. As cover88rotates about its axis, however, recess90formed on the outer edge of cover88exposes the light sensor to the light source of optical sensor86. At the moment recess90passes between the light sensor and the light source of optical sensor86, slide carrier assemblies20are docked in their respective stations12.

Once the light sensor is exposed to the light source of optical sensor86, optical sensor86transmits a signal to ECU25(described below) to deactivate motor70. While slide carrier assemblies20are docked in their respective stations12, the staining and/or rinsing operations commence. After the predetermined amount of time has expired, ECU25re-activates motor70until recess90again exposes the light sensor to the light source of optical sensor86. Sensor86is not limited to that shown and described. Sensor86may also be a switch, a Hall-Effect sensor, or any other sensor known to those skilled in the art without departing from the scope of the invention.

FIGS. 13-15depict perspective, right side elevation and partially exploded views, respectively, of guiding device80ofFIG. 12. While guiding device80is shown and described hereinafter, it should be understood that guiding devices79and80are structurally and functionally equivalent. Only one guiding device79or80may be necessary for operation of slide stainer10. Accordingly, although not shown, slide stainer10might only employ a single guiding device79or80.

Guiding device80may be considered as a component of drive mechanism30because guiding device80is configured to guide the motion of transport member26. Guiding device80generally includes plate92defining track94, toothed gear81rotatably mounted to plate92, and cover88mounted to toothed gear81. As described previously, toothed gear81is driven (i.e., rotated) by toothed belt72. Gear81is rotatably mounted to plate92. Plate92is either directly or indirectly mounted to housing11and is incapable of rotation. Fastener93(seeFIG. 15) passes through a hole defined in the axis of rotation of gear81and mounts through hole95defined in plate92thereby coupling gear81and plate92together. Although not shown, a bearing is provided between gear81and plate92to reduce friction therebetween upon rotation of gear81.

End96of pin32is mounted to transport member26(seeFIGS. 1 and 10) and the opposing end of pin32is positioned within track94of plate92. Because pin32is positioned within track94, pin32is forced to follow the trajectory of track94as gear81rotates. The path (i.e. path29) of pin32is illustrated inFIGS. 9A-9F. The trajectory of track94may be defined as substantially rectangular, substantially elliptical or defined in the shape of a rectangle having rounded corners.

The body of pin32is also positioned within elongated slot98(seeFIG. 15) that is defined in toothed gear81. Elongated slot98enables pin32to follow the trajectory of track94as toothed gear81rotates about its axis. In the absence of elongated slot98, pin32would bind against a surface of track94restricting gear81from rotation. As toothed gear81rotates about its axis, pin32slides along the length of elongated slot98.

To facilitate sliding action of pin32, pin32is mounted to sliding member100. Sliding member100is slidably mounted to rail102which is fixedly mounted to gear81. Sliding member100slides along a surface of rail102under the force of gravity and the rotational force of gear81. Rail102is fixedly mounted to gear81adjacent elongated slot98and extends substantially parallel to elongated slot98. Those skilled in the art will recognize that rail102may be formed directly on a surface of gear81and may not be a separate component, as shown. As sliding member100slides along a surface of rail102, pin32translates along the length of elongated slot98.

Cover88is mounted to gear81by a series of standoffs99extending between cover88and gear81. Cover88rotates along with year81. Standoffs99separate cover88from gear81to accommodate sliding member100and rail102. Cover88is provided to shield end-user's from the moving components of guiding device80. Elongated slot106is defined in cover88to accommodate the sliding action of pin32. The position, size and shape of elongated slot106corresponds to that of elongated slot98of gear81.

FIG. 16-18depict elevation, cross-sectional and exploded perspective views of slide carrier assembly20. Slide carrier assembly20includes slide carrier22and a plurality of laboratory slides24releasably mounted to slide carrier22. Handle106is provided on slide carrier22to facilitate handling of slide carrier assembly20. According to the exemplary embodiment illustrated, three (3) laboratory slides24are coupled to slide carrier22. It will be readily understood by those skilled in the art that any number of laboratory slides24may be releasably mounted to slide carrier22. As best shown inFIG. 17, slide carrier22includes a plurality of recesses108(four shown). Each recess108is sized to releasably captivate a slide. Slides24are releasable from slide carrier22, such that slides24may be individually examined by a laboratory technician, stored, or retained individually for further processing. Although not shown, slide carrier22may be integrated with a single slide.

Referring now toFIGS. 1 and 12, slide stainer10includes electronic control unit (ECU)25that is configured to control operation of slide stainer10. ECU25generally includes a programmable processor (not shown) and user interface27. ECU25receives power from a 12-volt DC power source (not shown) of slide stainer10. The user interface27includes a key pad for entering commands into ECU25and a display screen. By way of non-limiting example, the display screen may display the operating status of slide stainer10, time to completion, warning messages, commands entered via keypad, or any other message. Further details of ECU25are described hereinafter with reference to an exemplary operation of slide stainer10.

In operation of slide stainer10, an operator first positions a slide carrier assembly into the first station, i.e., station12a. As described later, the operator may position a slide carrier assembly into any station12athrough12nat any time. The operator enters a command into the keypad of user interface27to start the staining process. ECU25activates motor70to transport the slide carrier assembly from one station to the next station, as described with reference toFIGS. 9A-9F. Once a slide carrier assembly reaches the next station, ECU25is configured to temporarily deactivate motor70.

Specifically, ECU25interfaces with optical sensor86(seeFIG. 12) to control operation of motor70. Once the light sensor is exposed to the light source of optical sensor86, indicating that one staining cycle is complete, optical sensor86transmits a signal to ECU25to deactivate motor70. While slide carrier assemblies20are docked in their respective stations12, the staining, rinsing and/or drying operations commence.

To accomplish a rinsing operation, ECU25opens a valve (not shown) that is coupled to inlet port44to deliver water into rising station12dat a pre-determined flow rate. The time for staining, rinsing and/or drying the laboratory slides in stations12a-12nis set by the end-user via the keypad of user interface27. After the predetermined amount of time has expired, ECU25is configured to close the valve coupled to inlet port44and reactivate motor70until the light sensor is again exposed to the light source of optical sensor86.

Slide carrier assemblies may be loaded into the first station (or any other station) either before processing has started or after processing has started. A “pause-resume” function of ECU25permits the user to pause the transport mechanism after processing has started in order to load additional slide carrier assemblies20onto slide stainer10. The operator enters a command via the keypad of user interface27to alert ECU25that another slide carrier assembly has been loaded into the first station.

Each time transport member26transfers a processed slide carrier assembly20to storage vessel16, ECU25issues an audible alert to inform the operator that a processed slide carrier assembly is available for retrieval. If no more slide carrier assemblies20are positioned on transport member26, ECU25is configured to deactivate motor70. The operator physically removes one or more processed slide carrier assemblies and enters a command into the keypad of user interface27to inform ECU25that one or more processed slide carrier assemblies have been removed from storage vessel16. ECU25then adjusts its count of slide carrier assemblies contained within storage vessel16accordingly.

According to the exemplary embodiment, storage vessel16is sized to hold four processed slide carrier assemblies20. In operation, once three (3) processed slide carrier assemblies20are contained within storage vessel16, ECU25is configured to issue a distinctive audible warning (such as three beeps) alerting the operator to the near-filled condition. After the fourth processed slide carrier assembly20is inserted into storage vessel16, storage vessel16is completely filled with processed slide carrier assemblies. Accordingly, once the fourth processed slide carrier assembly20is inserted into storage vessel16, ECU25is configured to deactivate slide stainer10to prevent further processed slide carrier assemblies from being placed into the filled storage vessel16. Alternatively, although not shown, a sensor may be positioned within storage vessel16to detect when three or more processed slide carrier assemblies20are contained within storage vessel16. In operation, the sensor would transmit a signal to ECU25, which would issue a distinctive audible warning (such as three beeps) to alert the operator to the condition and/or deactivate motor70.

ECU25includes a programmable start position feature for staining protocols that do not require the use of all fourteen stations12a-12n. Using the start position feature, an end-user can specify which station12athrough12nis being used as the starting position. For example, for a protocol requiring only ten stations, the end-user would place a slide carrier assembly in station12e. By specifying that station12eis the starting position, ECU25can issue an audible warning once the slides that were originally positioned in station12ereach storage vessel16.

ECU25of slide stainer10is also configured to detect certain motion failures. When a motion error is detected, ECU25is configured to perform the following steps: deactivate motor70, briefly activate motor70in a reverse direction, deactivate motor70again, re-activate motor70in a forward direction in a second attempt to reach the desired position. If after the second attempt ECU25detects another motion failure, ECU25deactivates motor70and issues an audible alert and/or a visual alert on the display screen of user interface27.

ECU25includes other features for adjusting the operation of slide stainer10via the keypad of user interface27. For example, the number of times a slide carrier assembly is immersed in a single station may be adjusted via the keypad of user interface27. If the operator commands ECU25to immerse a slide carrier assembly more than once, ECU25would perform the following steps: activate motor70in a forward direction to immerse the slides in a station for a first time, deactivate motor70, activate motor70in a reverse direction to remove the slides from that station, deactivate motor70, re-activate motor70in a forward to immerse the slides in that same station for a second time, and so forth. As another example, if the stopping position of transport member26is sub-optimal, the position at which transport member26stops for processing may be adjusted by the operator via the keypad of user interface27. Those skilled in the automated slide staining art will recognize other functionalities for ECU25from the description herein.