Document reading device and image forming apparatus

An image forming apparatus comprising:

• a document reading device that reads a document;
• and
• an image forming unit that forms an image based on an output from the document reading device,
• the document reading device having:
• a document image acquisition unit that scans a document and obtains a document image;
• a document image storage unit that stores the document image obtained by the document image acquisition unit;
• a compression unit that compresses the document image stored in the document image storage unit;
• a determination unit that determines whether or not a document image file compressed by the compression unit has normally been produced;
• and
• a setting change unit that, in the case where it is determined that the document image file compressed has not been produced normally, changes a setting so as to recompress the document image stored in the document image storage unit with another setting.