Patent ID: 7967408

Claim:
A printer for printing on one surface and the other surface of a sheet-like printing medium fed in a predetermined feed direction, comprising: a first printing part provided in the feed direction, for printing on the one surface; a second printing part provided on the upstream side of the first printing part in the feed direction, driven simultaneously with the first printing part, for printing on the other surface; a storage area, in which first image data corresponding to the first printing part and second image data corresponding to the second printing part are stored; and an adjustment part for adjusting printing start positions of printing operations performed by the first and second printing parts by shifting the readout order of the first image data to be stored in the storage area toward the end side by adding blank data or a space area to a leading head part of the first image data in accordance with a positional difference between the first printing part and the second printing part in the feed direction so as to cause the first printing part and the second printing part to start printing simultaneously.