Canon Kabushiki Kaisha

Hitoshi Arai

Kimiyoshi Hayashi

Kazuhiko Hirooka

Kenichi Takeda

Toshio Honma

Yoshihiko Hirose

In an image forming apparatus for forming an ordinary copy or a tonality image for an original image for a printing master, original image data is divided into a predetermined area, and pixel density within the area is subjected to a density conversion in accordance with screen half-toning information which will increase density information toward the approximate center of these pixels, by way of example. The original image data or the density-converted image data is converted into a binary-coded signal conforming to the density, and an output image is formed in accordance therewith. Preferably, a specific mark is supperimposed on the output image.

Image forming apparatus

A scanning optical apparatus according to the present invention comprises a light source, a modulator for modulating a light flux emitted from the light source, an image forming device for forming an image of the light flux from the light source to a predetermined position, a deflector for deflecting the light flux from the light source in a predetermined position, a photosensitive device for sensing the light flux deflected by the deflector, an adjusting device for adjusting an image forming position of the light flux by the image forming device in correspondence to a signal obtained by the photosensitive device and an inhibiting device when the light flux emitted from the light source is being modulated by the modulator in correspondence to a predetermined signal. By the scanning optical apparatus of the invention, the focal deviation can be always stably corrected and a stable image with high density can be obtained.

Scanning optical apparatus having focal position deviation detecting and

In an image forming apparatus for forming an ordinary copy or a tonality image for an original image for a printing press, original image data is divided into data within a predetermined area and that outside the area, and pixel density within the area is subjected to a density conversion in accordance with screen half-toning information which will increase density information toward the approximate center of these pixels, by way of example. The original image data or the density-converted image data is converted into a binary-coded signal conforming to the density, and an output image is formed in accordance therewith. Preferably, plural types of non-linear correction tables are provided and a tone-conversion is performed selecting an appropriate correction table for each pixel, or for each line, of the density-converted image data. Preferably, the original image data is binary coded by a pattern signal having a long period, and the density-converted image data is binary coded by a pattern signal having a short period. The foregoing is applied to color-separated image data of each color. Preferably, the image data is divided, in accordance with color, into predetermined areas having the same or a different number of pixels, or into predetermined areas having a planar phase which differs for each color, and a screen angle is applied thereto.

An image processing apparatus comprises a pulse-width-modulation signal generator for processing an image signal generated by an image signal generator by using a pattern signal to produce a pulse-width modulation signal. The pulse-width modulation signal generator generates first and second pattern signals of different periods, selects one of the pattern signals in accordance with a property of an image to be processed, and inhibits the generation of the non-selected pattern signal.

Image processing apparatus with interference suppression

An image processing apparatus in which a digital image signal is produced and characteristics thereof are converted, e.g., gradation-processed. The result of this processing is used to produce a pulse-width-modulated signal, which is used for image formation. Image forming conditions are detected and the processing is controlled in accordance with the result of such detection.

Image processing apparatus with image formation condition detection for

An image processing apparatus includes a D/A converter for generating an analog image signal, a variable resistor for changing an output range of the analog image signal generated by the D/A converter, and a comparator for processing the analog image signal generated by the variable resistor by using an analog pattern signal and for outputting a pulse width modulated signal. The analog pattern signal may be a triangular wave signal, a saw-tooth wave signal, a sine wave signal, or a trapezoidal wave signal. In another version, selection is performed between predetermined data and a generated image signal and the selected signal is processed using an analog pattern signal (e.g., a triangle wave) to output a pulse width modulated signal. A D/A converter may be used to convert the output of the selection. The output range of the DAC may be variable.

Image processing apparatus in which the minimum and maximum widths of a

An image processing apparatus has a semiconductor laser for modulating a light beam, a beam detector for detecting the beam, a selector for selecting an output from a digital data input unit or a black signal generator circuit, a comparator for pulse-width modulating an output from the selector received through a D/A converter, and a video enable (VE) signal generator circuit for generating a VE signal for switching the selector.

Image processing apparatus

An image reading apparatus has a CCD, a reference point on a reference plate, an image signal reading circuit, an image signal control circuit, and a CPU. When an optical element is shifted from its normal position, such a positional error can be automatically corrected without requiring readjustment of the optical element.

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Yokohama, Japan

Hitoshi Arai