I'm thinking that a roller gives me the most conceptual freedom to pivot to multiple new plans should initial ones fail. 

The maximum time the cleaning procedure can take is 10 seconds for a solution to pass. The fastest method is to roll across the shorter axis, which is 143mm. 143mm is short enough that the circumference of a 50mm roller is longer (157mm). Considering that the roller would cover the 360mm span, I think this would be a required minimum diameter anyway for stiffness. 

Additionally, I'm thinking about part curing and that the UV LEDs I have planned for the side walls may not be able to evenly cure the part. By putting a high powered led bar facing down on the roller bar (or a seperate bar, similar to the X axes in the #SecSavr Sublime [gd0036] ) I could obtain these benefits:

1. The UV light can fully cure the part more evenly than a traditional cure station that rotates the part.
2. By using black, light absorbing wall coatings for the build area instead of reflective ones, the UV light can cure the part whilst the uncured resin on the lamination film is being swapped or replenished.
3. Less UV light sources will be needed, reducing costs and improving energy efficiency.
4. A 2-20 minute cure will not be needed.
5. A door with a window can be used, meaning that a camera will not be required to check on parts while printing.

This UV LED bar will only be turned on after all exposures have been completed for the layer. Since the layer is assumed to be devoid of uncured resin, I can't imagine any overexposure issues arising from different resins with different curing times, such as opaque and transparent materials.

For the roller, the plans I've come up with to try are:

1. The roller does N number of passes and cleans itself when docked on something like a continuous roll of paper towel. A UV LED then cures the resin on the paper towel. Ideally, N = 1 or 2 and the roller speed is 150mm/s.
2. A layer of cleaning fluid is depositied over the roller on the first pass. Then, the uncured resin and cleaning fluid is removed on subsequent passes. 2 rollers might be needed.