Abstract: A line-head control device that controls a line head includes: a calculation unit that divides image data into a plurality of areas in sub-scanning direction and calculates a printing percentage for each of the areas; an allocation unit that allocates a total correction amount, for correcting magnification of the image data in the sub-scanning direction, to the areas according to the printing percentage for each of the areas calculated by the calculation unit; and a control unit that changes an emission period of the light emitted from the line head so as to satisfy a partial correction amount that is an allocation of the total correction amount to each of the areas, exposes the image carrier to the light emitted from the line head with the changed light emission period, thereby causing a latent image to be formed on the image carrier based on the image data.

Abstract: An image processing apparatus includes a reading part configured to optically read skew amount measurement patterns and opposite ends of a paper sheet; an image skew amount detecting part configured to detect skew amounts on a color basis based on the skew amount measurement patterns; a paper sheet skew amount detecting part configured to detect a skew amount of the paper sheet based on a displacement between the opposite ends of the paper sheet; a skew correction amount calculating part configured to calculate skew correction amounts of the respective colors based on the skew amounts; and a skew correcting part configured to shift the images to correct the skews by recording input image data in plural lines of a line memory, dividing the input image data into plural areas in a main scanning direction, and setting line delay amounts on an area basis based on the skew correction amounts.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.

Abstract: An embodiment of the image processing apparatus for controlling the lighting of a line head that is driven with binary data and performs exposure with subline lighting to thereby form images, includes: a subline generating unit that generates a plurality of sublines from a same image data; an inclination correcting unit that exposes the generated sublines so as to generate correction image data used to correct an inclination of an exposure position; a gradation control unit that controls the lighting of sublines based on the correction image data generated by the inclination correcting unit to express gradation; and a light intensity correction unit that corrects and controls the light intensity based on the correction image data generated by the inclination correcting unit, wherein an output of the gradation control unit and an output of the light intensity correction unit are input into the line head in parallel.

Abstract: An image forming apparatus performs pseudo gradation processing using dithering, and includes an image carrier; a plurality of light-emitting element arrays arranged in a main-scanning direction and including a plurality of light-emitting elements; an image forming unit performing lighting control of the arrays and forming a pattern image on the image carrier; a detecting unit detecting a density of the pattern image; a position detecting unit detecting a position in the main-scanning direction of the detecting unit with respect to the light-emitting element arrays; a determining unit that, based on the detected position, determines whether the detecting unit is positioned at a proper detection position with respect to the pattern image on which noise has no effect; and an operation control unit that, when the detecting unit is positioned at the proper detection position, performs an image density detection operation on the pattern image using the detecting unit.

Abstract: An image forming apparatus includes plural image forming units of plural colors, each including a print head including plural LED chips aligned in a main scanning direction; a screen angle selecting unit that selects screen angles for the plural colors respectively based on the amounts of skew of the plural image forming units; an image processing unit that performs image processing on input data to be expressed by pixels of the plural colors such that the pixels of the colors have the corresponding screen angles selected by the screen angle selecting unit; a correction amount determining unit that determines a total amount of skew correction based on the amount of skew detected by the skew detection unit, and determines the amounts of skew correction in the sub-scanning direction for predetermined groups of the pixels, based on the total amount of skew correction, for each of the colors.

Abstract: A light source control circuit of an optical writing device, admitting connection of light sources and forming an electrostatic latent image on a photosensitive element by controlling a connected light source, includes: a skew correction unit that corrects a skew of a main scanning line of an electrostatic latent image formed by the light source relative to the photosensitive element; a pattern generating unit that outputs image data for forming a predetermined pattern in an electrostatic latent image; a local deviation correction unit that corrects a local deviation of an electrostatic latent image formed by the light source on the main scanning line by acquiring image data processed to form the pattern and by performing a predetermined process; a light source control unit that causes the light source to emit light based on image data in which the local deviation has been corrected; and a setting value input unit.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.

Abstract: An optical writing device stores pieces of dithering information indicating dithering patterns whose densities are different, each piece of dithering information including pieces of identification information associated with pixels of the corresponding dithering pattern, and stores pieces of pixel setting information in which pieces of colored/colorless information indicating each of the pixels is colored or colorless are associated with the pieces of identification information, the pieces of colored/colorless information being set based on a resolution of a light source for forming an electrostatic latent image. The optical writing device also includes a control unit configured to arrange the same dithering patterns in a way that the dithering patterns form a pattern with a given size, and cause the light source to emit light based on information generated by setting the pixels of each of the same dithering patterns to be colored or colorless in accordance with the pixel setting information.

Abstract: A light emission control device images an electrostatic latent image on a photosensitive element by a plurality of light emitting elements corresponding to a line in a second direction perpendicular to a first direction which is a rotational direction the photosensitive element. The light emission control device includes: a detecting unit that detects a rotational position of the photosensitive element, in the first direction, corresponding to a line in the second direction; an acquiring unit that acquires a distance between the light emitting elements and the rotational position of the photosensitive element in the first direction detected by the detecting unit; and a control unit that controls light emission by the light emitting elements according to the distance acquired by the acquiring unit and corrects a fluctuation in a density of a visible image converted from the electrostatic latent image.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.

Abstract: An optical writing device that forms an electrostatic latent image on a photoreceptor. The device includes a pixel-information acquiring unit, a line-pixel-information storage unit that stores the acquired pixel information corresponding to a plurality of lines for each main scanning line, a light source device that exposes the photoreceptor with a period corresponding to an N-fold sub-scanning direction resolution of the pixel information, a positional-shift-information storage unit that stores a positional shift information, a sub-line counting unit that counts a sub-line period, a reading-line selecting unit that performs N times of selection that determines which main scanning line is selected as the line from which the pixel information is read out, on the basis of a calculated value from the counted value of the sub-line period and the positional shift information, and a pixel-information reading unit.

Abstract: A pixel information acquiring unit acquires multilevel pixel information in which one pixel is expressed in multilevel scales. A line pixel information storing unit stores the multilevel pixel information for each main scanning line. A light emission control unit optically exposes a photosensitive element by controlling a binary light source on the basis of the multilevel pixel information. The photosensitive element is exposed to the binary light source with a period corresponding to N-fold in a sub scanning direction resolution of the multilevel pixel information, wherein N is a positive integer, so that the N times exposures corresponds to an exposure for one pixel in an original resolution. The switch on/off statuses of the binary light source are controlled in the N times exposures for each pixel, on the basis of lighting rate information for converting the multilevel scales into a lighting rate in the N times exposures.

Abstract: An optical writing device stores pieces of dithering information indicating dithering patterns whose densities are different, each piece of dithering information including pieces of identification information associated with pixels of the corresponding dithering pattern, and stores pieces of pixel setting information in which pieces of colored/colorless information indicating each of the pixels is colored or colorless are associated with the pieces of identification information, the pieces of colored/colorless information being set based on a resolution of a light source for forming an electrostatic latent image. The optical writing device also includes a control unit configured to arrange the same dithering patterns in a way that the dithering patterns form a pattern with a given size, and cause the light source to emit light based on information generated by setting the pixels of each of the same dithering patterns to be colored or colorless in accordance with the pixel setting information.

Abstract: An optical writing device includes: a light source including arrays arranged in a main scanning direction, each array including light-emitting elements arranged in the main scanning direction; a correction-value holding unit to hold, correspondingly with a light-emitting element, a correction value for changing timing to read out pixel data stored in an image storage unit; and a light-source drive unit to drive the light source by reading out the stored pixel data stored, according to the correction value. The correction-value holding unit includes a first area for holding a first correction value corresponding to a first light-emitting element located at an end of an array and a second area for holding a second correction value corresponding to a second light-emitting element other than the first light-emitting element, the first holding area being larger than the second holding area.

Abstract: An image forming apparatus includes plural image forming units of plural colors, each including a print head including plural LED chips aligned in a main scanning direction; a screen angle selecting unit that selects screen angles for the plural colors respectively based on the amounts of skew of the plural image forming units; an image processing unit that performs image processing on input data to be expressed by pixels of the plural colors such that the pixels of the colors have the corresponding screen angles selected by the screen angle selecting unit; a correction amount determining unit that determines a total amount of skew correction based on the amount of skew detected by the skew detection unit, and determines the amounts of skew correction in the sub-scanning direction for predetermined groups of the pixels, based on the total amount of skew correction, for each of the colors.

Abstract: An image forming apparatus performs pseudo gradation processing using dithering, and includes an image carrier; a plurality of light-emitting element arrays arranged in a main-scanning direction and including a plurality of light-emitting elements; an image forming unit performing lighting control of the arrays and forming a pattern image on the image carrier; a detecting unit detecting a density of the pattern image; a position detecting unit detecting a position in the main-scanning direction of the detecting unit with respect to the light-emitting element arrays; a determining unit that, based on the detected position, determines whether the detecting unit is positioned at a proper detection position with respect to the pattern image on which noise has no effect; and an operation control unit that, when the detecting unit is positioned at the proper detection position, performs an image density detection operation on the pattern image using the detecting unit.

Abstract: An image forming apparatus includes a light source, a polygon mirror, and a plurality of photosensitive elements. The polygon mirror has a plurality of reflection surfaces that reflect a light beam at different angles. The light beams deflected by the reflection surfaces travel along different optical paths and impinge on different photosensitive elements. A light-beam control unit controls emission of the light beam from the light source depending on a distance between the deflecting unit and the photosensitive elements thereby performing an f? correction of the light beam.

Abstract: A line-head control device that controls a line head includes: a calculation unit that divides image data into a plurality of areas in sub-scanning direction and calculates a printing percentage for each of the areas; an allocation unit that allocates a total correction amount, for correcting magnification of the image data in the sub-scanning direction, to the areas according to the printing percentage for each of the areas calculated by the calculation unit; and a control unit that changes an emission period of the light emitted from the line head so as to satisfy a partial correction amount that is an allocation of the total correction amount to each of the areas, exposes the image carrier to the light emitted from the line head with the changed light emission period, thereby causing a latent image to be formed on the image carrier based on the image data.

Abstract: An optical writing device forms an electrostatic latent image on a photosensitive element by a connected light source controlled by a light source control circuit that includes: a pixel data output unit; a pixel data correcting unit that corrects a skew between main scanning line of electrostatic latent image and photosensitive element and a local deviation of the electrostatic latent image on the main scanning line, and outputs pixel data; a pattern generating unit that outputs pixel data for forming a predetermined pattern in an electrostatic latent image; a first light source control unit for causing a first light source, that needs correction of the local deviation, to emit light; a second light source control unit for causing a second light source, that does not need correction of the local deviation, to emit light; and a switch that switches between a first transmission status and a second transmission status.