Abstract: An image forming apparatus includes a body, a toner container that is removably set in the body and contains toner, a toner supplier to supply the toner from the toner container to the body, a memory that stores container information that is information of the toner container, and circuitry. The circuitry is to determine, after the toner container is set in the body, based on the container information acquired from the memory, whether the toner container set in the body is same as a toner container set in the body in a past and the container information satisfies a predetermined condition, and to drive the toner supplier in a case where the toner container set in the body is determined to be same as the toner container set in the body in the past and the container information satisfies the predetermined condition.

Abstract: A characteristic detector includes two electrodes facing each other to form a passage through which a medium passes, a cover disposed between the two electrodes, a current generator to supply a current between the two electrodes, a capacitance gauge to measure a capacitance generated between the two electrodes, and circuitry. The two electrodes have a shape or an arrangement in which at least two points on a leading end of the medium enter the passage with a time lag. The cover covers one of the two electrodes in connection with a size of the medium. The capacitance gauge detects the size of the medium based on the measured capacitance. The circuitry calculates a characteristic of the medium based on the capacitance measured by the capacitance gauge and the size of the medium detected by the capacitance gauge.

Abstract: Switch units control ON and OFF of communication between a master device and slave devices. Signal levels of communication lines between switch units and slave devices are maintained at a predetermined level. A switch unit in a first stage is turned on and off by a first switch control signal. A switch unit in a second stage is turned on and off by a switch control signal generated based on a level of a communication line in the first stage and the first switch control signal. A switch unit in each of subsequent stages is turned on and off by a switch control signal generated based on a level of a communication line in a preceding stage and a switch control signal in a second preceding stage. A portion of ground short circuit is identified based on states of communication between the master device and the slave devices.

Abstract: A characteristic detector includes two electrodes facing each other to form a passage through which a medium passes, a cover disposed between the two electrodes, a current generator to supply a current between the two electrodes, a capacitance gauge to measure a capacitance generated between the two electrodes, and circuitry. The two electrodes have a shape or an arrangement in which at least two points on a leading end of the medium enter the passage with a time lag. The cover covers one of the two electrodes in connection with a size of the medium. The capacitance gauge detects the size of the medium based on the measured capacitance. The circuitry calculates a characteristic of the medium based on the capacitance measured by the capacitance gauge and the size of the medium detected by the capacitance gauge.

Abstract: A motor connection detecting device includes: a bipolar stepping motor; a motor driver adapted to control current to be supplied to the bipolar stepping motor; and a controller connected to the bipolar stepping motor and the motor driver. The controller detects voltage of regenerative current generated during motor ON time in which current flows in the bipolar stepping motor, and determines abnormal connection of the bipolar stepping motor. The detected voltage is voltage generated during a fast decay period according to a current attenuation method of the regenerative current.

Abstract: Switch units control ON and OFF of communication between a master device and slave devices. Signal levels of communication lines between switch units and slave devices are maintained at a predetermined level. A switch unit in a first stage is turned on and off by a first switch control signal. A switch unit in a second stage is turned on and off by a switch control signal generated based on a level of a communication line in the first stage and the first switch control signal. A switch unit in each of subsequent stages is turned on and off by a switch control signal generated based on a level of a communication line in a preceding stage and a switch control signal in a second preceding stage. A portion of ground short circuit is identified based on states of communication between the master device and the slave devices.

Abstract: A motor connection detecting device includes: a bipolar stepping motor; a motor driver adapted to control current to be supplied to the bipolar stepping motor; and a controller connected to the bipolar stepping motor and the motor driver. The controller detects voltage of regenerative current generated during motor ON time in which current flows in the bipolar stepping motor, and determines abnormal connection of the bipolar stepping motor. The detected voltage is voltage generated during a fast decay period according to a current attenuation method of the regenerative current.

Abstract: A sheet thickness detector incorporated in an image forming apparatus includes a sheet conveying member to rotate and convey a sheet in a sheet conveyance direction, a driven sheet conveying member to contact the sheet conveying member and form at least one first transfer nip therebetween in a lateral direction and to displace by an amount equivalent to a thickness of the sheet passing through the first transfer nip and rotated with the sheet conveying member in the sheet conveyance direction, a displacement member to contact the sheet conveying member and form a second transfer nip smaller than the first transfer nip in the lateral direction and to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip and supported at a support member, and a displacement amount detector to detect an amount of displacement of the displacement member.

Abstract: A sheet thickness detector incorporated in an image forming apparatus includes a sheet conveying member to rotate and convey a sheet in a sheet conveyance direction, a driven sheet conveying member to contact the sheet conveying member and form at least one first transfer nip therebetween in a lateral direction and to displace by an amount equivalent to a thickness of the sheet passing through the first transfer nip and rotated with the sheet conveying member in the sheet conveyance direction, a displacement member to contact the sheet conveying member and form a second transfer nip smaller than the first transfer nip in the lateral direction and to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip and supported at a support member, and a displacement amount detector to detect an amount of displacement of the displacement member.

Abstract: A sheet thickness detector incorporated in an image forming apparatus includes a sheet conveying member to rotate and convey a sheet in a sheet conveyance direction, a driven sheet conveying member to contact the sheet conveying member and form at least one first transfer nip therebetween in a lateral direction and to displace by an amount equivalent to a thickness of the sheet passing through the first transfer nip and rotated with the sheet conveying member in the sheet conveyance direction, a displacement member to contact the sheet conveying member and form a second transfer nip smaller than the first transfer nip in the lateral direction and to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip and supported at a support member, and a displacement amount detector to detect an amount of displacement of the displacement member.

Abstract: A sheet thickness detector incorporated in an image forming apparatus includes a sheet conveying member to rotate and convey a sheet in a sheet conveyance direction, a driven sheet conveying member to contact the sheet conveying member and form at least one first transfer nip therebetween in a lateral direction and to displace by an amount equivalent to a thickness of the sheet passing through the first transfer nip and rotated with the sheet conveying member in the sheet conveyance direction, a displacement member to contact the sheet conveying member and form a second transfer nip smaller than the first transfer nip in the lateral direction and to displace by an amount equivalent to the thickness of the sheet passing through the second transfer nip and supported at a support member, and a displacement amount detector to detect an amount of displacement of the displacement member.

Abstract: An image forming apparatus includes a skew correcting unit that performs skew correction by dividing an input image that has undergone a halftone process into image data in a predetermined skew correction area in a main scanning direction and by shifting the image data in the skew correction area in a sub-scanning direction; an edge detecting unit that detects whether a pixel at a division position is an edge pixel based on concentrations of a set of pixels including the pixel at the division position; a correction area determining unit that, if detected that the pixel at the division position is the edge pixel, determines a correction area that is an area of pixels including the edge pixel to be subjected to concentration correction within the skew correction area; and an edge correcting unit that corrects concentrations of the pixels within the correction area.

Abstract: A density detector detects a first density of a first pattern and a second density of a second pattern from a density-correction determination patch. A density-correction-value calculator calculates a density correction value from the first and the second densities. A noise-occurrence determination unit determines whether a target pixel is a noise generating pixel that causes a change of a local density due to a change in a relation with a nearby pixel. A density correction processor performs a density correction process on the target pixel by adding or subtracting the density correction value to or from the target pixel or the nearby pixel.

Abstract: An image forming apparatus capable of minimizing degradation in density correction as a part of skew correction includes a noise-occurrence determining unit, a correction-target-pixel selecting unit, a density correcting unit, and a phase correcting unit. When the noise-occurrence determining unit determines that noise would appear, the density correcting unit performs density correction on a correction target pixel that is determined by the correction-target-pixel selecting unit. The phase correcting unit corrects an output point in time of image data of the density-corrected correction target pixel in a pixel period during which the image data can be output so as to output the image data at a position displaced away from a shift position or toward a shift position.

Abstract: An image forming apparatus capable of accurately compensating an increase or decrease of a toner area coverage resulting from shifting that is performed to correct skew is provided. A color density of image data represented by a correction target pixel is corrected such that the increase or decrease in the toner area coverage on the correction target pixel is compensated excluding a toner area coverage on the correction target pixel covered by a toner image that would be formed based on a color density of image data to be represented by a neighboring pixel of the correction target pixel. This effectively reduces banding noise on an output of the image data and prevents degradation in image quality.

Abstract: A pattern generating unit generates correction patterns on a transfer belt. Detection sensors detect the correction patterns, and amounts of magnification correction, amounts of misregistration in the main- and the sub-scanning direction are calculated. The amount of skew between each of colors is then calculated, and a position where an image is divided and a direction for shifting a divided image are determined. Possible dividing-positions are also determined, and a calculated dividing position and each of the possible dividing positions are compared with one another. Then, a possible dividing position closest to the calculated dividing position is set as an actual dividing position.

Abstract: An image forming apparatus includes a skew correcting unit that performs skew correction by dividing an input image that has undergone a halftone process into image data in a predetermined skew correction area in a main scanning direction and by shifting the image data in the skew correction area in a sub-scanning direction; an edge detecting unit that detects whether a pixel at a division position is an edge pixel based on concentrations of a set of pixels including the pixel at the division position; a correction area determining unit that, if detected that the pixel at the division position is the edge pixel, determines a correction area that is an area of pixels including the edge pixel to be subjected to concentration correction within the skew correction area; and an edge correcting unit that corrects concentrations of the pixels within the correction area.

Abstract: A density detector detects a first density of a first pattern and a second density of a second pattern from a density-correction determination patch. A density-correction-value calculator calculates a density correction value from the first and the second densities. A noise-occurrence determination unit determines whether a target pixel is a noise generating pixel that causes a change of a local density due to a change in a relation with a nearby pixel. A density correction processor performs a density correction process on the target pixel by adding or subtracting the density correction value to or from the target pixel or the nearby pixel.

Abstract: An image forming apparatus capable of minimizing degradation in density correction as a part of skew correction includes a noise-occurrence determining unit, a correction-target-pixel selecting unit, a density correcting unit, and a phase correcting unit. When the noise-occurrence determining unit determines that noise would appear, the density correcting unit performs density correction on a correction target pixel that is determined by the correction-target-pixel selecting unit. The phase correcting unit corrects an output point in time of image data of the density-corrected correction target pixel in a pixel period during which the image data can be output so as to output the image data at a position displaced away from a shift position or toward a shift position.

Abstract: An image forming apparatus capable of accurately compensating an increase or decrease of a toner area coverage resulting from shifting that is performed to correct skew is provided. A color density of image data represented by a correction target pixel is corrected such that the increase or decrease in the toner area coverage on the correction target pixel is compensated excluding a toner area coverage on the correction target pixel covered by a toner image that would be formed based on a color density of image data to be represented by a neighboring pixel of the correction target pixel. This effectively reduces banding noise on an output of the image data and prevents degradation in image quality.