A new apparatus is disclosed which is useful for high throughput of samples without necessity of interrupting any analysis performed on said apparatus for reloading of disposables. The pattern includes at least one of the predetermined color or a color that is not included in the image. A drive sleeve is disposed within the shaft and is longitudinally translatable relative to the shaft to transition the end effector assembly between a first state and a second state. The peak of the switching noise is diffused in the frequency range by sequential selection of switching frequencies, and noise level is reduced by diffusion of noise energy. The reflector may include a vented portion that is not optically coupled to the LED based illumination module to allow air to pass through the reflector.