Image reading apparatus, image forming apparatus, and image reading method

An image forming apparatus, comprising:

• a printer unit configured to form images on a recording medium;
• a reading unit configured to read a plurality of documents on a document table and generate an overall scan image as color image data including images of all the documents in the plurality of documents;
• and
• a controller configured to:
• isolate an image of each document from the overall scan image,
• perform a color determination on each of the isolated images to determine if the document corresponding to the isolated image is a color document or a non-color document, and
• encode each of the isolated images with an image encoding method selected based on the color determination for the isolated image.

An image reading method, comprising:

• reading a plurality of documents on a document table and generating an overall scan image as color image data including images of all the documents in the plurality of documents;
• isolating an image of each document from the overall scan image;
• performing a color determination on each of the isolated images to determine if the document corresponding to the isolated image is a color document or a non-color document;
• and
• encoding each of the isolated images with an image encoding method selected based on the color determination for the isolated image.