Patent ID: 8786885

Claim:
An image forming apparatus comprising: an image data memory configured to store image data to be printed on a back of a body of an envelope and image data to be printed on a face of a flap of the envelope, as backside image data of the envelope in a closed state having the flap folded on the back of the body; an image data mapper configured to generate print data of first backside image data to be printed on the back of the envelope body and print data of second backside image data to be printed on the face of the flap, based on the backside image data stored in the image data memory; and a printer configured to perform double sided printing, wherein first backside image data is printed on the back of the envelope body, based on the print data of the first backside image data generated at the image data mapper, and a second backside image data is printed on the face of the flap, based on the print data of the second backside image data generated at the image data mapper, wherein the flap of the envelop is an open state during printing and a single image is reconstructed as a combination of the image printed on the back of the envelop body and the image printed on the face of the flap, and a suction device configured to draw air and suction the envelop fed to the printer, a medium transfer system configured to transfer the envelop being suctioned by the suction device, wherein the printer configured to make a print on the envelop being transferred by the medium transfer system, wherein the image data mapper is configured to eliminate image data in a region at an edge of the flap in the second backside image data, the region is in a leading position in a transfer direction to generate print data provided with a margin in the eliminated region, as the print data of the second backside image data.