Patent ID: 6307579
Filing Date: 2001-10-23
Classification: G02B,H04N

Abstract:
A magnification error correction method for an image forming apparatus including:a printer unit which includes: a photosensitive drum motor which rotates a photosensitive drum having scanned surface and which is capable of correcting its rotational speed; and a polygonal motor which rotates a polygonal mirror scanning on the scanned surface of the photosensitive drum along a main scanning direction by a light beam, and which forms an image corresponding to an input image data;a scanner unit which provides an image data corresponding to a document image and which includes: a line sensor scanning a document along a main scanning direction; and a carriage motor which drives a carriage that scans the document along a feed direction and which is capable of correcting its speed;a control unit for inputting a motor correction value and displaying the motor correction value;a reference pattern generating unit for generating a reference pattern data; anda memory for storing a correction value input by the control unit, comprising the steps of:a first correction step of providing a first polygonal motor correction value and a first drum motor correction value to the polygonal motor and the photosensitive drum motor so that an image formed by the printer unit has a desired magnification, on the basis of the reference pattern data provided from the reference pattern generating unit, and storing these correction values in the memory;a second correction step of scanning a document, on which a predetermined pattern is printed, by the scanner unit, providing a second polygonal motor correction value and a carriage motor correction value to the polygonal motor and the carriage motor so that an image printed using the printer unit has a desired magnification, storing these correction values in the memory, and providing the first drum motor correction value to the photosensitive drum motor; anda step of forming an image using the first polygonal motor correction value, the carriage motor correction value and a second drum motor correction value calculated from the first and second polygonal motor correction values and the first drum motor correction value in the case of scanning a document by the scanner unit, and forming an image by the printer unit in a state that a main scanning/feed direction of the image is inverted.