Abstract: An image forming apparatus for forming images on a recording medium on the basis of an electrophotography system includes a calculator for determining the quantities of state and quantities of control using fuzzy sets and for calculating, for each color, quantities of control. Each quantity of control corresponds to one of the detected quantities of state from a degree to which the quantity of state belongs to each fuzzy set. An extractor for extracting, in accordance with predetermined rules, a main quantity of control for each color in a specific position within the area represented by each quantity of control calculated by the calculator.

Abstract: An image processing apparatus for processing a half tone image comprises: an input device to input an image signal; an image forming circuit to form an image onto a recording medium such as a photosensitive drum on the basis of the image signal supplied by the input device; a generator to generate a plurality of image data having different densities; a density detector to detect a density of the image formed on the recording medium by the image forming circuit on the basis of the image data generated from the generator; and a forming circuit to form a plurality of density conversion coefficients to convert the density of the image signal supplied by the input device on the basis of the densities of the plurality of images which are detected by the density detector.

Abstract: An image forming apparatus is disclosed which is capable of controlling the quality of the images formed in accordance with detected environmental conditions. This is accomplished in the invention through the use and control of predetermined values which are dependent upon the detected environmental state. A correcting device corrects the predetermined value based on results detected by an image density detecting sensor, whereby the correcting amounts are varied in accordance with the detected environmental state. A constant image density is always obtained regardless of variations in the inner environment of the image formation system.

Abstract: The present invention provides an image forming apparatus for reproducing an image from an original, wherein a character portion and an intermediate contrast portion of an original are discriminated and different density converting tables are used for the character portion and for the intermediate contrast portion. When a original includes both a character portion and the intermediate contrast portion, the density converting table for a character portion is applied to the character portions and the density converting table for intermediate contrast portion is applied to the intermediate contrast portions to form the image.