1. An image forming apparatus, comprising: a document image acquiring portion that acquires a document image; an integration pattern determining portion that makes settings relating to integration for each integrated document image when plural document images are integrated into a recording sheet as integrated document images and thereby determines an integration pattern of the integrated document images for the recording sheet; an integrated document image generating portion that generates the integrated document images corresponding to the integration pattern from the document images acquired by the document image acquiring portion according to the integration pattern determined by the integration pattern determining portion; and a print portion that prints the integrated document images generated by the integrated document generating portion onto the recording sheet in the integration pattern.