US Patent 7280244 Printer simultaneously printing on both surfaces of a sheet

A method of manipulating print data in a printer capable of simultaneously printing on both surfaces of a sheet of print media, the method including the steps of: receiving first data relating to a first page to be printed in a first memory; transferring the first data from the first memory to a second memory; receiving second data relating to a second page to be printed in the first memory; and simultaneously accessing the first and second data to simultaneously print the first and second pages on both surfaces of the print media.