Canon Kabushiki Kaisha

Canon Kabushiki Kaisah

Izuru Horiuchi

Yasutomo Furuta

Taku Yamagami

Shigeru Jinnai

Jun Hirabayashi

Keizo Isemura

Kenji Hiromatsu

Takahiro Ushiro

Yoichi Takikawa

Tomohiro Tamaoki

Ryuichi Araki

Shunichi Komatsu

Atsushi Inoue

Yuji Sakaegi

Satoru Kutsuwada

Koji Okabe

Saijiro Endo

Masashi Hori

Kazuyoshi Suzuki

Saburo Nakazato

Fusang Chou

An exposure head includes a substrate on which light sources are mounted, and a condensing optical system. A memory stores a profile indicating correction gains for exposure amounts. A sensor detects a temperature. A processor acquires a correction gain that corresponds to a position of a light source that reached an exposure timing, corrects, for each of the light sources, an exposure amount of the light source with the correction gain corresponding to the position of the light source, and adjusts, for each of the light sources, a reference position of the corresponding correction gain in the profile in accordance with the temperature detected by the sensor.

Controlling exposure apparatus used in image forming apparatus

An image forming apparatus includes a photoreceptor; an image signal generating unit configured to generate an image signal based on input image data; a light emitting portion configured to emit light based on the image signal and expose the photoreceptor; a driving unit configured to drive the light emitting portion; a first substrate in which the driving unit is provided and a plurality of the light emitting portions is provided in a direction parallel to a rotational axis direction of the photoreceptor; an exposure head including the first substrate; a reference clock signal generating unit configured to generate a reference clock signal that is a clock signal of a constant frequency; a modulated clock signal generating unit configured to generate a modulated clock signal by performing spread spectrum on the reference clock signal, the modulated clock signal being a composite wave in which odd-order harmonics are combined with a fundamental wave when a triangular wave is subjected to Fourier series expansion; a transmission unit configured to superimpose the modulated clock signal on the image signal and transmit the superimposed signal to the first substrate; a second substrate on which the image signal generating unit, the modulated clock signal generating unit, and the transmission unit are provided; and an extraction circuit that is mounted on the first substrate and extracts the modulated clock signal from the superimposed signal transmitted from the transmission unit.

Image forming apparatus

An image forming apparatus includes a photosensitive member, an exposure portion including surface light emitting element arrays each including light emitting elements, and a clock generating portion. The clock generating portion generates a reference clock signal and a spread spectrum modulation clock signal. The exposure portion exposes the photosensitive member to light by sequentially subjecting a predetermined number of the light emitting elements to light emission control on the basis of a signal obtained by subjecting the modulation clock signal to modulation with image data. A modulation cycle in which a frequency of the modulation clock signal is modulated is n times (n: integer of n&#x3e;1) an exposure cycle which is a time in which the light emitting elements are subjected to the light emission control on the basis of the reference clock signal.

An image forming apparatus, including: a light source configured to emit a light beam; a rotary polygon mirror having a plurality of reflection surfaces configured to deflect the light beam; a beam detector configured to receive the light beam to output a pulse; a pulse interval measurement unit configured to measure a pulse interval of pulses output from the beam detector; a reflection surface identification unit configured to identify each of the plurality of reflection surfaces; a storage portion configured to store a reference pulse interval of each of the plurality of reflection surfaces; a correction amount calculation unit configured to calculate a correction amount based on the pulse interval and the reference pulse interval for each of the plurality of reflection surfaces; and a light source control unit configured to control the light source based on the correction amount.

An image forming apparatus including: a photosensitive member rotatable in a first direction; an exposure unit configured to scan the photosensitive member with a light beam in a second direction substantially orthogonal to the first direction to form a latent image; a generation unit configured to generate data corresponding to a gradation of a predetermined pixel of input image data by dividing the predetermined pixel by a predetermined division number; a calculation unit configured to calculate an ideal division number depending on a position of the predetermined pixel in the second direction; and a determination unit configured to determine the predetermined division number based on the ideal division number, wherein the determination unit feeds back an error between an ideal division number and a division number for a pixel at a position preceding the predetermined pixel in determining the predetermined division number for the predetermined pixel.

An image forming apparatus, including: a light source; a photosensitive member rotatable in a first direction; a deflecting unit configured to deflect the light beam in a second direction orthogonal to the first direction; a conversion unit configured to convert image data into a plurality of bit data corresponding to a density on a pixel-by-pixel basis; a specifying unit configured to specify a pixel size that is a number of divided pixels forming a pixel according to a position of the pixel in the second direction; and a correction unit configured to correct the plurality of bit data according to the pixel size, wherein the specifying unit specifies pixel sizes of pixels after an arrangement of the pixels in the second direction is replaced for each pixel group, the pixel group being obtained by dividing, with respect to each predetermined number of pixels, pixels arranged in the second direction.

Image forming apparatus and correction method therefor

Provided is an image forming apparatus including: an exposure unit scanning a photosensitive member with a light beam radiated by a light source which is driven by a driving unit; a determination unit determining a number of bit data per pixel for a predetermined pixel of image data; a selection unit having conversion conditions for converting the image data into a bit pattern for the driving, and selecting a predetermined conversion condition depending on the determined number of bit data, the conversion conditions set such that numbers of bit data included in the obtained bit pattern for the radiating are different, and that the numbers of bit data are different depending on the image data; and a generation unit generating, based on the selected predetermined conversion condition and a density value of the predetermined pixel, the bit pattern for generating a PWM signal for the driving for the predetermined pixel.

A correction method for an image forming apparatus including a light source including a plurality of light emitting points, a photosensitive member configured to rotate in a first direction, and a deflection unit configured to deflect light beams emitted from the light source in a second direction orthogonal to the first direction to form scanning lines, the correction method including: a storing step of storing information on positional deviation of the scanning lines in the first direction; a conversion step of converting positions of pixels of an input image by performing coordinate transformation based on the information so that an interval of the scanning lines becomes a predetermined interval; and a filtering step of determining pixel values of pixels of an output image by subjecting pixel values of the pixels of the input image after the coordinate transformation to a convolution operation.

Correction method for image forming apparatus

An incidence angle of laser light with respect to a photosensitive member in a main-scanning direction is different depending on an exposure position. Hence, the spot shape of the laser light on the photosensitive member is different in the main-scanning direction. A filter coefficient is changed in the main-scanning direction, and image data is corrected with the filter coefficient.

A correction method for an image forming apparatus including a light source including a plurality of light emitting points, a photosensitive member configured to rotate in a first direction so that a latent image is formed thereon with light beams emitted from the light source, and a deflecting unit configured to deflect the light beams emitted from the light source in a second direction orthogonal to the first direction to form scanning lines, the correction method including a correction step of correcting sparseness and denseness of density in the first direction caused by deviation of the scanning lines in the first direction by moving a predetermined pixel in the first direction in accordance with the deviation of the scanning lines and causing a pixel value of the predetermined pixel to be output in accordance with a movement of the predetermined pixel.

An image forming apparatus includes a laser light source configured to emit a light beam, a photoconductor drum configured to be driven for rotation on which a latent image is formed by the light beam, a rotatable polygonal mirror configured to rotate about a rotation axis and have a plurality of mirror planes which deflect the light beam so that the light beam scans the photoconductor drum, and a CPU configured to perform a dither process on input image data and correct image data which has been subjected to the dither process using correction amounts based on inclinations of the plurality of mirror planes relative to the rotation axis of the rotatable polygonal mirror.

By dispersing within an image magnified pixels subjected to magnification correction with the use of pseudorandom numbers, an occurrence of a moire pattern in an image is suppressed.

Image forming apparatus having image magnification correction

A correction method for an image forming apparatus including a light source including light emitting points, a photosensitive member configured to rotate in a first direction, and a deflecting unit configured to deflect light beams emitted from the light source in a second direction orthogonal to the first direction, the correction method includes: a first correction step of correcting sparseness and denseness of density in the first direction by moving a predetermined pixel in the first direction, and causing a pixel value of the predetermined pixel to be output or not to be output in accordance with movement of the predetermined pixel; and a second correction step of correcting the pixel value of the predetermined pixel by moving the pixel value of the predetermined pixel in the second direction so that a pixel value is caused to be output or not to be output with a plurality of continuous pixels.

An image forming apparatus including: a first processing unit configured to subject input image data to tone correction with use of a tone correction table; a second processing unit configured to subject the image data to dither processing; a correction unit configured to correct the image data with use of a correction amount based on positional deviation of scanning lines caused by a mirror face tangle error; a deflection unit configured to deflect light beams emitted from the light source with a mirror face to form the scanning lines; an extraction unit configured to extract a feature amount of the tone correction table; and an adjustment unit configured to adjust a change in tone characteristics in a case where the feature amount extracted by the extraction unit exceeds a predetermined range.

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Tokyo, Japan

Izuru Horiuchi