In a computer output microfilmer (COM) comprising a computer output read out device having a magnetic recording tape, a central processor unit, and a recording unit, the computer output read-out device is provided with a buffer storage and a data processing device. The data read out from the magnetic recording tape are stored in the buffer storage and read out therefrom under the control of the data processing device. Thereby, the steps of reading out the data of page (N+2) from the magnetic recording tape, processing the data of page (N+1) in the central processor unit, and recording the data of page (N) in the recording unit are conducted in parallel.
