US 9,146,514 B2 · Image forming apparatus and image forming method for correcting registration deviation

Abstract

There exists a problem that, for registration correction, carrying out less-than-one-pixel-basis correction and one-pixel-basis correction for an image after half toning using screen processing causes unevenness in density when it is hard for linearity of image density against a PWM to come out. Processing of interpolation is carried out so that the way how a halfdot is formed may always becomes the same after the interpolation processing. By applying a matrix in consideration of a dot direction which may be broken by the interpolation processing at the time of the screen processing, conversion in which a way of locating the half dot maintains relation of vertical inversion in a subscanning direction is carried out, and less-than-one-pixel-basis correction is carried out.

Claims22

Dependent claims

An image processing apparatus transmitting image data to an image forming unit which forms an image by modulating a pulse width on the basis of the image data, comprising:

a storing unit constructed to store a deviation amount in a subscanning direction of an image formed by the image forming unit;
an obtaining unit constructed to obtain multivalued image data having a first resolution;
a screen processing unit constructed to generate, by performing a screen processing of a 1-bit-binary on the obtained multivalued image data, binary image data having the first resolution, the binary image data being a 1-bit-per-pixel image data;
a converting unit constructed to convert the generated binary image data into multivalued image data having a second resolution corrected on the basis of the stored deviation amount, the second resolution being less than the first resolution, wherein a number of tones per pixel of the converted image data having the second resolution is less than a number of tones per pixel of the obtained image data having the first resolution;
and
a transmitting unit constructed to transmit the converted image data having the second resolution to the image forming unit, wherein the image forming unit modulates a pulse width on the basis of the transmitted converted image data having the second resolution.

3 more elements

An image processing method of transmitting image data to an image forming unit which forms an image by modulating a pulse width on the basis of the image data, the method comprising:

storing into a storage a deviation amount in a subscanning direction of an image formed by the image forming unit;
obtaining multivalued image data having a first resolution;
generating, by performing a screen processing of a 1-bit-binary on the obtained multivalued image data, binary image data having the first resolution, the binary image data being a 1-bit-per-pixel image data;
converting the generated binary image data into multivalued image data having a second resolution corrected on the basis of the stored deviation amount, the second resolution being less than the first resolution, wherein a number of tones per pixel of the converted image data having the second resolution is less than a number of tones per pixel of the obtained image data having the first resolution;
and
transmitting the converted image data having the second resolution to the image forming unit, wherein the image forming unit modulates a pulse width on the basis of the transmitted converted image data having the second resolution.

3 more elements

Dependencies are inferred from the claim text.

Image forming apparatus and image forming method for correcting registration deviation

Life of this patent

Image forming apparatus and image forming method for correcting registration deviation

Life of this patent

Abstract

Claims22