Image forming apparatus and image forming method

Abstract

An image forming apparatus includes an intermediate transfer body; a generating unit generating test pattern data; a storage unit storing a color displacement amount; a correcting unit correcting the test pattern data and image data based on the color displacement amount currently stored in the storage unit; a forming unit forming a test pattern based on the test pattern data corrected by the correcting unit on the intermediate transfer body at predetermined intervals, and forming an image based on the image data corrected by the correcting unit on the intermediate transfer body; a detecting unit detecting the test pattern formed on the intermediate transfer body; an updating unit determining an amount of change of the color displacement amount from a result of detection by the detecting unit, and updating the color displacement amount stored in the storage unit by using the amount of change of the color displacement amount.

Description

technical field [0001] The present invention relates to an imaging device, and more particularly, to an imaging device in which a plurality of images having different colors are superimposed on each other to form an output image. Background technique [0002] In color image forming devices using electrophotographic technology, a tandem-type is the mainstream. In such a color imaging device, a plurality of image forming units are arranged in series to form a full-color image in a single path. Generally, images formed by a plurality of image forming units corresponding to colors such as yellow, magenta, cyan, and black are transferred to an intermediate transfer belt (intermediate transfer body) for primary transfer. Subsequently, a plurality of images in various colors on the intermediate transfer belt are taken at once to a recording sheet (recording medium) for secondary transfer, and an output pattern is formed thereon. The output image is then fused on the recording she...

AI Technical Summary

Problems solved by technology

This operation requires high precision and low moving components, which results in increased cost

And it takes a long time until the correction is completed, and therefore the correction operation cannot be performed frequently

[0006] (2) The amount of color shift (amount of registration error) may change over time due to deformation of the optical system or support members as a result of temperature changes in the device, thus making it difficult to maintain the color shift in the immediate High image quality available after control

Also, as a non-linear color shift factor mainly due to precision error in the f-θ lens, there may be a magnification shift where the scanning speed in the main scanning direction of the photosensitive drum (image carrier) is not constant (uniform) When the local magnification of the main scan magnification of the formed image changes, resulting in a position dependent velocity shift of the drum in the main scan direction

[0016] This non-linear component of the color shift amount cannot be corrected by the color shift control method according to the prior art

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