A printing system with a pre-determined printing rate, in which a modular print media sheets feeding system feeds unprinted sheets to the printing system from at least two separate sheet separator/feeders and sheet stacks under the control of a programmed sheet feeding algorithm which alternately feeds the sheets into at least two separate fed sheet streams at a sheet feeding cycle time for each separator/feeder of approximately one-half or less of the printing system printing rate and with sheet feeding commands such that the separate sheet separator/feeders feed their respective sheets into their respective fed sheet streams at programmed times which allow the fed sheet streams to interleave into a single fed sheet stream at a sheet merging position at the full pre-determined printing rate of the printing system before being fed to the printing system.