Abstract: An image forming apparatus includes: an obtaining unit that radiates light from a light-emitting unit onto the image carrier and that obtains an output value of a light-receiving unit having received the light reflected from the image carrier; a light amount setting unit that calculates a required light amount value and that sets a light amount adjusting value; a detecting unit that detects a pattern image on the image carrier and by judging whether an output value obtained by radiating light of the light amount adjusting value exceeds a predetermined threshold; and a controller that controls image formation on the image carrier based on a detected result, wherein the detecting unit reduces the threshold when the required light amount value exceeds the limiting value depending on degree of the excess.

Abstract: A light amount detector includes a light emitter, a light receiver, and a light amount detection unit. The light emitter emits light on a detection pattern formed on a detection surface of an image carrier. The light receiver detects diffused light reflected from the detection pattern. The light amount detection unit detects an amount of light received by the light receiver based on detection output of the light receiver. One of the light emitter and the light receiver is provided at a position directly opposite to the detection surface, such that a distribution of sensitivity of the light receiver detecting the diffused light is substantially symmetrical with respect to a detection output peak when the detection surface is substantially parallel to a hypothetical line connecting the light emitter with the light receiver.

Abstract: A pattern forming unit forms a color-misalignment detection pattern on an image carrier. A light-intensity detecting unit detects the color-misalignment detection pattern formed on the image carrier by irradiating the image carrier with a light and detecting light intensity of a reflected light from the image carrier. A color-misalignment-amount detecting unit detects an amount of a color misalignment of an image based on the light intensity of the reflected light detected by the light-intensity detecting unit. A spot of the light on the image carrier is elongated in a main-scanning direction.

Abstract: An image forming apparatus includes: an obtaining unit that radiates light from a light-emitting unit onto the image carrier and that obtains an output value of a light-receiving unit having received the light reflected from the image carrier; a light amount setting unit that calculates a required light amount value and that sets a light amount adjusting value; a detecting unit that detects a pattern image on the image carrier and by judging whether an output value obtained by radiating light of the light amount adjusting value exceeds a predetermined threshold; and a controller that controls image formation on the image carrier based on a detected result, wherein the detecting unit reduces the threshold when the required light amount value exceeds the limiting value depending on degree of the excess.

Abstract: A color shift detection pattern forming part forms a color shift detection pattern. A sensor detects color shift in the color shift detection pattern. A color shift amount computing part calculates an amount of color shift. A color shift correcting part corrects the calculated amount of color shift. A correction amount computing part computes an amount of correction to correct the computed amount of color shift. A correcting part corrects the computed amount of color shift based on the computed amount of correction based on a setting value for controlling a color shift state. A determining part determines whether an abnormality is detected in the computed amount of color shift or in the computed amount of correction of color shift based on a result of computation of the amount of color shift or a result of computation of the amount of correction. A fixed value setting part sets a specific fixed value to the setting value of the correcting part.

Abstract: Light quantity is adjusted in an image forming apparatus including an image carrier by forming a pattern on the image carrier, detecting a light quantity of a reflecting light from the pattern and outputting a voltage, reading the light quantity of the reflecting light from the pattern detected once based on a present light quantity set, calculating from the light quantity read, a set light quantity corresponding to a target output voltage for printing, and setting the set light quantity calculated.

Abstract: A light amount detector includes a light emitter, a light receiver, and a light amount detection unit. The light emitter emits light on a detection pattern formed on a detection surface of an image carrier. The light receiver detects diffused light reflected from the detection pattern. The light amount detection unit detects an amount of light received by the light receiver based on detection output of the light receiver. One of the light emitter and the light receiver is provided at a position directly opposite to the detection surface, such that a distribution of sensitivity of the light receiver detecting the diffused light is substantially symmetrical with respect to a detection output peak when the detection surface is substantially parallel to a hypothetical line connecting the light emitter with the light receiver.

Abstract: A pattern forming unit forms a color-misalignment detection pattern on an image carrier. A light-intensity detecting unit detects the color-misalignment detection pattern formed on the image carrier by irradiating the image carrier with a light and detecting light intensity of a reflected light from the image carrier. A color-misalignment-amount detecting unit detects an amount of a color misalignment of an image based on the light intensity of the reflected light detected by the light-intensity detecting unit. A spot of the light on the image carrier is elongated in a main-scanning direction.

Abstract: In a position deviation detecting method for an image forming device, first and second patterns formed in different colors on image supporting mediums are transferred to an intermediate transfer medium in an overlapping manner, the first patterns formed in a color with high sensor sensitivity and the second patterns formed in a color with low sensor sensitivity. The first and second patterns on the transfer medium are read using a light-receiving unit of a pattern detection sensor. An amount of position deviation in a main scanning direction between two of a plurality of colors is detected. The first patterns are set in a fixed position in the main scanning direction and the second patterns are shifted. Output values of the light-receiving unit are measured from the first and second patterns, and the amount of position deviation in the main scanning direction is computed based the measured output values.

Abstract: A color shift detection pattern forming part forms a color shift detection pattern. A sensor detects color shift in the color shift detection pattern. A color shift amount computing part calculates an amount of color shift. A color shift correcting part corrects the calculated amount of color shift. A correction amount computing part computes an amount of correction to correct the computed amount of color shift. A correcting part corrects the computed amount of color shift based on the computed amount of correction based on a setting value for controlling a color shift state. A determining part determines whether an abnormality is detected in the computed amount of color shift or in the computed amount of correction of color shift based on a result of computation of the amount of color shift or a result of computation of the amount of correction. A fixed value setting part sets a specific fixed value to the setting value of the correcting part.

Abstract: An image forming apparatus includes a light receiving unit that irradiates light and receives a light reflected from patterns on a transfer member. The patterns include an upper layer as a reference color with low lightness overlapping a lower layer serving as a non-reference color with high lightness. At least the lower layer is halftone. A deviation amount detector in the image forming apparatus detects a deviation amount of the lower layer relative to the upper layer according to density information of the patterns based on the light received by the light receiving unit.

Abstract: Light quantity is adjusted in an image forming apparatus including an image carrier by forming a pattern on the image carrier, detecting a light quantity of a reflecting light from the pattern and outputting a voltage, reading the light quantity of the reflecting light from the pattern detected once based on a present light quantity set, calculating from the light quantity read, a set light quantity corresponding to a target output voltage for printing, and setting the set light quantity calculated.

Abstract: In a position deviation detecting method for an image forming device, first and second patterns formed in different colors on image supporting mediums are transferred to an intermediate transfer medium in an overlapping manner, the first patterns formed in a color with high sensor sensitivity and the second patterns formed in a color with low sensor sensitivity. The first and second patterns on the transfer medium are read using a light-receiving unit of a pattern detection sensor. An amount of position deviation in a main scanning direction between two of a plurality of colors is detected. The first patterns are set in a fixed position in the main scanning direction and the second patterns are shifted. Output values of the light-receiving unit are measured from the first and second patterns, and the amount of position deviation in the main scanning direction is computed based the measured output values.

Abstract: An image forming apparatus includes a light emitting array composed of a plurality of light emitting elements that emits light fluxes. An imaging element array may be provided so as to perform imaging with the light fluxes on a prescribed plane. A three dimensional exposure intensity distribution of the light flux is obtained per each light emitting element. A prescribed attribute is obtained from each of the exposure intensity distributions. A plurality of comparison values for the entire exposure valid region may be obtained from different units which consist of two or more successive attributes. Prescribed light emitting quantities enabling all of the comparison values to fall within a prescribed range may be determined and set to respective light emitting elements.

Abstract: An image forming apparatus includes a light emitting array composed of a plurality of light emitting elements that emits light fluxes. An imaging element array may be provided so as to perform imaging with the light fluxes on a prescribed plane. A three dimensional exposure intensity distribution of the light flux is obtained per each light emitting element. A prescribed attribute is obtained from each of the exposure intensity distributions. A plurality of comparison values for the entire exposure valid region may be obtained from different units which consist of two or more successive attributes. Prescribed light emitting quantities enabling all of the comparison values to fall within a prescribed range may be determined and set to respective light emitting elements.