1. A color image forming apparatus comprising: a standard pattern data storage unit for storing standard pattern data for color correction; a standard pattern forming unit for forming a standard pattern for color correction on a copying paper in accordance with said standard pattern data; a standard pattern reading unit for reading a standard pattern formed on a document being read; a color correction condition modification unit for modifying color correction conditions in accordance with standard pattern data obtained by reading said standard pattern formed on said document and said standard pattern data stored in said standard pattern data storage unit in advance; and a correction unit for performing color correction on read data of the entire image of said document in accordance with said modified color correction conditions.