Canon Kabushiki Kaisha

Sono Gu

Yoshito Mizoguchi

Satoru Fukushima

Takashi Hasegawa

Hisashi Fukushima

Yukio Nagase

Kazuhisa Kemmochi

Toshinori Ando

Yoshinori Nagao

Digital image data corresponding to an original read in by a CCD is stored in a page memory in pixel units, and a CPU reads the stored image data and creates a histogram. For an original having many high-density portions, an image is formed using a LOG conversion table which generates density data that enables reproduction of the tonality of the high-density portions. For an original which is comparatively faint, an image is formed using a LOG conversion table which generates density data that assures tone reproduction up to the maximum density of the original even if high-density portions cannot be reproduced. As a result, tone reproduction suited to the original image can be realized at all times.

Image processing method and apparatus for achieving tone reproduction suited to the image

An image processing apparatus comprises image signal input means, tone means for toning the input image signal to produce a pulse width modulated signal, beam generation means for generating a beam modulated by the pulse width modulated signal, and detection means for detecting an output power of the beam generated by the beam generation means. The tone means switches an output mode of the pulse width modulated signal in accordance with the detection output of the detection means.

Image processing apparatus

An image forming apparatus including an electrophotographic photosensitive member; a latent image forming device for forming an electrostatic latent image by charging the photosensitive member and exposing it to light information; a controller for controlling the latent image forming means to control tone reproducibility of the electrostatic latent image; an image forming device for forming an image having light, halftone and dark portions, for tone controls, a detector for detecting a state of the tone control image, and wherein the controller controls the electrostatic latent image forming device on the basis of a datum from the detector and predetermined tone correcting information.

Image forming apparatus having tone correcting function

When forming an image in which a half-tone image area such as photograph, screen, or the like and characters and fine lines exist the half-tone image area and the character and fine line portion are stably reproduced without deteriorating the picture qualities of both of them and, particularly, the character and fine line portion can be clearly reproduced. A digital image signal generated from an image reader is stored into an image memory on a pixel unit basis. A CPU subsequently reads the stored digital image signal and forms a frequency distribution function (density histogram) as a detection frequency of corresponding density values every pixel. The density level value of the portion in which the detection frequency is locally high is detected from the formed density histogram. The density level values are converted into at least one density value by a gradation correction circuit. An image having an excellent gradation reproducibility in a range from a low density portion to a high density portion can be formed by the converted density value.

Image forming apparatus which forms halftone images mixed with

A multi-image forming apparatus for forming a multi-image by sequentially transferring images formed at a plurality of image forming stations including image bearing members onto a transfer sheet and aims to prevent the damage due to the friction thereof. The apparatus is so designed that, while a transfer sheet conveying means is being engaged by the image bearing members of the plural image forming stations arranged along a transfer sheet feeding direction, the transfer sheet conveying means and the image bearing members are driven without stopping one of these elements (i.e., image bearing members or transfer sheet conveying means) alone.

Multi-image forming apparatus

A color image forming apparatus includes an electrophotographic photosensitive member; a device for forming latent images by optical scanner with light information corresponding to colors; plural developing devices for developing in different colors; a detector for an ambient condition; and a device for changing a tone reproducing property of the latent image forming device using one of stored tables in accordance with an output of the detector.

Image forming apparatus which changes its tone reproducing property in

There are provided an image forming apparatus and method and apparatus for processing an image for the image forming apparatus, comprising: gradation reproducing means having different gradation reproducing characteristics; a color processing circuit for color processing in accordance with the gradation reproducing characteristic; and a process selecting circuit for selecting signal processes in the color processing circuit and the gradation reproducing means in accordance with an image region. Further, the color processing circuit has a masking coefficient train or UCR coefficients which are determined in accordance with the gradation reproducing characteristic. The process selecting circuit selects the signal processes in the color processing circuit and the gradation reproducing means in accordance with the image region.

Color image forming apparatus and method and apparatus for processing

An image forming apparatus has exposure unit for emitting light modified in accordance with image information, the light quantity of said exposure unit being variable, image forming unit for forming image on a photosensitive medium in accordance with light emitted from the exposure unit, detector for detecting the surface state of the photosensitive medium, and controller for optimizing the light quantity of the exposure unit in accordance with the output of the detecting unit. The control unit obtains a potential versus image information variation characteristic of the photosensitive medium based on the output of the detecting unit and sets the light quantity of the exposure unit such that the characteristic approximate a straight line.

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Ohmiya, Japan

Sono Gu