Image forming apparatus which excels in reproducibility of colors, fine lines and gradations even in a copy made from a copied image

A method of forming an image with an image forming apparatus, comprising the steps of:

• obtaining image data by reading a document with a document reading unit;
• detecting a standard pattern from said image data;
• detecting whether the detected standard pattern includes data corresponds to one of a plurality of machine codes stored in a table, each machine code have gradation correction conditions stored corresponding thereto;
• reading gradation correction conditions stored corresponding to said one of the plurality of machine codes, and setting said one of the plurality of machine codes and said corresponding gradation correction conditions in said correction unit;
• and
• performing gradation correction on said image data by a correction unit, and printing an image on a copying paper.

An image forming apparatus comprising:

• a machine code storage unit for storing a plurality of machine codes, each machine code having image correction conditions stored corresponding thereto;
• an image reading unit for reading a pattern image formed on a document and detecting whether the read pattern image includes data corresponding to one of the plurality of machine codes stored in the machine code storage unit;
• a machine code fetch unit for fetching said one of the plurality of machine codes and the image correction conditions corresponding thereto when data corresponding to said one of the plurality of machine codes stored in the machine code storage unit is detected in the read pattern image;
• an image correction condition modifying unit for modifying image correction conditions in accordance with the fetched image correction conditions;
• and
• an image correcting unit for correcting image data in accordance with the modified image correction conditions, the image data being obtained by reading the document.