What Chan said. At the lab I worked at we had a number of such easels, which were used under normal enlargers for quantity printing. You print the batch and then feed that whole portion of the roll into the processor. Prints then would be cut up after they were developed and dry. It might take some looking, but I bet you could find a used one cheap from one of the many labs that have shut down their darkrooms. Hopefully not everything related has been trashed.