Abstract: An image scanning apparatus includes plural light sources, an image sensor, a driving circuit, and a controller. The plural light sources are configured to emit light of plural colors. The image sensor is configured to scan an image on the basis of the light sequentially emitted by the plural light sources. The driving circuit is configured to drive the plural light sources. The controller is configured to supply to the driving circuit an instruction of light-emitting pulse widths of the light sources. Further, the controller corrects the light-emitting pulse widths in monochrome scanning on the basis of a rising time and a falling time of driving currents conducted through the light sources by the driving circuit so as to cause the light-emitting pulse widths to agree with light-emitting pulse widths based on predetermined color balance ratios of the plural colors, respectively.

Abstract: An image scanning apparatus includes plural light sources, an image sensor, a driving circuit, and a controller. The plural light sources are configured to emit light of plural colors. The image sensor is configured to scan an image on the basis of the light sequentially emitted by the plural light sources. The driving circuit is configured to drive the plural light sources. The controller is configured to supply to the driving circuit an instruction of light-emitting pulse widths of the light sources. Further, the controller corrects the light-emitting pulse widths in monochrome scanning on the basis of a rising time and a falling time of driving currents conducted through the light sources by the driving circuit so as to cause the light-emitting pulse widths to agree with light-emitting pulse widths based on predetermined color balance ratios of the plural colors, respectively.

Abstract: In the image processing apparatus according to the present disclosure, a data processing unit derives a density variation component for at least one modulation period from a difference between a reference plate reading value when the illumination is turned off, a reference plate reading value when the illumination is turned on, and black reference data and white reference data in synchronization with modulation of the SS clock, and corrects the image data with the density variation component. The white reference data indicates the light distribution of the illumination in the main scanning direction, and the data processing unit corrects the density variation component on the basis of the difference between the white reference data and the black reference data, and corrects the image data with the corrected density variation component.

Abstract: In image processing apparatus, a sample hold unit samples and holds an output signal of the image sensor. A timing signal generating circuit generates a sampling clock to specify a sampling timing of the sample hold unit. A controller sets a phase of the sampling clock to the timing signal generating circuit. In an adjustment process that adjusts the phase of the sampling clock, the controller (a) causes the image sensor to scan a reference board, (b) sets predetermined plural phases to the timing signal generating circuit in turn, (c) calculates average values of image data obtained correspondingly to the plural phases and calculates a value of a parameter that indicates a fluctuation width of the average values, and (d) sets the phase of the sampling clock as a phase corresponding to the smallest value of the parameter.

Abstract: In the image processing apparatus according to the present disclosure, a data processing unit derives a density variation component for at least one modulation period from a difference between a reference plate reading value when the illumination is turned off, a reference plate reading value when the illumination is turned on, and black reference data and white reference data in synchronization with modulation of the SS clock, and corrects the image data with the density variation component. The white reference data indicates the light distribution of the illumination in the main scanning direction, and the data processing unit corrects the density variation component on the basis of the difference between the white reference data and the black reference data, and corrects the image data with the corrected density variation component.

Abstract: In image processing apparatus, a sample hold unit samples and holds an output signal of the image sensor. A timing signal generating circuit generates a sampling clock to specify a sampling timing of the sample hold unit. A controller sets a phase of the sampling clock to the timing signal generating circuit. In an adjustment process that adjusts the phase of the sampling clock, the controller (a) causes the image sensor to scan a reference board, (b) sets predetermined plural phases to the timing signal generating circuit in turn, (c) calculates average values of image data obtained correspondingly to the plural phases and calculates a value of a parameter that indicates a fluctuation width of the average values, and (d) sets the phase of the sampling clock as a phase corresponding to the smallest value of the parameter.

Abstract: In an image processing device, a sampling portion selects, as a target line, each of four reference lines that pass through a pixel of interest in a 3×3 target pixel group. When a difference between data among a pair of neighboring pixels, positioned along the target line, is within a predetermined first selection reference range, and with respect to at least one of two areas on both sides of the target line, all differences among data of three neighboring pixels that exist in the area are within a predetermined second selection reference range, the sampling portion selects the pair of neighboring pixels as the sample pixels. When a difference between data of the pixel of interest and an average value of the sample pixels exceeds a predetermined correction reference range, the device corrects the data of the pixel of interest to a value based on the sample average value.

Abstract: In an image processing device, a sampling portion selects, as a target line, each of four reference lines that pass through a pixel of interest in a 3×3 target pixel group. When a difference between data among a pair of neighboring pixels, positioned along the target line, is within a predetermined first selection reference range, and with respect to at least one of two areas on both sides of the target line, all differences among data of three neighboring pixels that exist in the area are within a predetermined second selection reference range, the sampling portion selects the pair of neighboring pixels as the sample pixels. When a difference between data of the pixel of interest and an average value of the sample pixels exceeds a predetermined correction reference range, the device corrects the data of the pixel of interest to a value based on the sample average value.

Abstract: First representative pixel data is a maximum amount of light, when a light source is turned off. Second representative pixel data and third representative pixel data respectively represent a minimum amount of light and a maximum amount of light for a conspicuous channel to which a piece of data representing an amount of light smaller than an amount of light corresponding to a first threshold belongs. In an image reading device, a determination device, when the third representative pixel data represents an amount of light that is equal to or larger than an amount of light corresponding to at least a second threshold corresponding to the first representative pixel data, or a third threshold corresponding to the second representative pixel data and the first representative pixel data, determines that a device state is defective.

Abstract: First representative pixel data is a maximum amount of light, when a light source is turned off. Second representative pixel data and third representative pixel data respectively represent a minimum amount of light and a maximum amount of light for a conspicuous channel to which a piece of data representing an amount of light smaller than an amount of light corresponding to a first threshold belongs. In an image reading device, a determination device, when the third representative pixel data represents an amount of light that is equal to or larger than an amount of light corresponding to at least a second threshold corresponding to the first representative pixel data, or a third threshold corresponding to the second representative pixel data and the first representative pixel data, determines that a device state is defective.

Abstract: This image reading device includes an image sensor module, an environment maintaining portion, and a level correction portion. The image sensor module includes a light emitting portion and a plurality of single-channel light amount sensors. The environment maintaining portion maintains, at a constant state, a light receiving environment for a reference portion forming an end portion, of a single-channel light amount sensor, which corresponds to an end portion of the main scanning region. The level correction portion corrects, each time the image sensor module outputs detection data that corresponds to the main scanning region, a level of the detection data from each of all the single-channel light amount sensors in accordance with a deviation between a level of the detection data regarding the reference portion and a reference level set in advance.

Abstract: An image reading device includes an image sensor, a color reference portion, a test control portion, a standard distribution information storage portion, a type determination portion, and an abnormality notification portion. The image sensor is capable of outputting detection data of an amount of received light from each of a plurality of partial scanning areas, each at an individual channel. The test control portion is configured to cause the image sensor to operate under a plurality of test operation conditions different in resolution, when a document is not present. If a distribution state of the detection data at each channel acquired under each test operation condition does not match any of standard distribution information, the abnormality notification portion notifies an abnormality of another device related to the image sensor. The standard distribution information represents a standard distribution state of data at each channel under each test operation condition.

Abstract: This image reading device includes an image sensor module, an environment maintaining portion, and a level correction portion. The image sensor module includes a light emitting portion and a plurality of single-channel light amount sensors. The environment maintaining portion maintains, at a constant state, a light receiving environment for a reference portion forming an end portion, of a single-channel light amount sensor, which corresponds to an end portion of the main scanning region. The level correction portion corrects, each time the image sensor module outputs detection data that corresponds to the main scanning region, a level of the detection data from each of all the single-channel light amount sensors in accordance with a deviation between a level of the detection data regarding the reference portion and a reference level set in advance.

Abstract: An image reading device includes an image sensor, a color reference portion, a test control portion, a standard distribution information storage portion, a type determination portion, and an abnormality notification portion. The image sensor is capable of outputting detection data of an amount of received light from each of a plurality of partial scanning areas, each at an individual channel. The test control portion is configured to cause the image sensor to operate under a plurality of test operation conditions different in resolution, when a document is not present. If a distribution state of the detection data at each channel acquired under each test operation condition does not match any of standard distribution information, the abnormality notification portion notifies an abnormality of another device related to the image sensor. The standard distribution information represents a standard distribution state of data at each channel under each test operation condition.

Abstract: An image reading device includes a light source, an image sensor, a transport unit, and a control unit. While, during reading of a target to be read by the image sensor, the control unit causes the transport unit to accelerate the read rate of the image sensor to a reference read rate or to decelerate the read rate thereof from the reference read rate, the control unit causes the light source to light up, within the read time, with timing brought close to a read section from a lighting start point to a lighting end point in the case of reading one line in the reference read time.

Abstract: An image reading device includes a changed-pixel detection unit and a determination unit. The changed-pixel detection unit detects, from image data read by the image reading unit, a changed pixel having a pixel value that differs from that of an adjacent pixel in the main scanning direction. The pixel value may differ by more than a predetermined value. The changed-pixel detection unit detects the position of the changed pixel in the main scanning direction. The determination unit determines that image data corresponding to positions of the changed pixel for the image data obtained by reading the document corresponds to a foreign image. The positions are consecutive in the sub-scanning direction. The positions of the changed pixel are detected for the image data obtained by reading the document and the image data obtained by reading the white guide member.

Abstract: The present disclosure relates to an image scanner and an image forming apparatus equipped with the image scanner, and more particularly to a technique of detecting that dew condensation occurs on a transparent member for placing a document thereon.

Abstract: Acquiring image data for each color component by guiding the reflected light from a read position on a contact glass, to a line sensor for each color component, detecting a provisional foreign matter region in one image data, determining a first condition on the basis of the number of pixels constituting the provisional foreign matter region, determining a second condition on the basis of the average value of the density values of all of the pixels within the provisional foreign matter region when the first condition is satisfied, and determining whether or not foreign matter is present at a read position corresponding to the one color component when the second condition is satisfied on the basis of the density value of the pixel corresponding to the provisional foreign matter region in one other image data and the fourth reference value that has been set in advance.

Abstract: An image reading device includes a changed-pixel detection unit and a determination unit. The changed-pixel detection unit detects, from image data read by the image reading unit, a changed pixel having a pixel value that differs from that of an adjacent pixel in the main scanning direction. The pixel value may differ by more than a predetermined value. The changed-pixel detection unit detects the position of the changed pixel in the main scanning direction. The determination unit determines that image data corresponding to positions of the changed pixel for the image data obtained by reading the document corresponds to a foreign image. The positions are consecutive in the sub-scanning direction. The positions of the changed pixel are detected for the image data obtained by reading the document and the image data obtained by reading the white guide member.

Abstract: An image scanning device comprises a white reference board having a uniform white color; an irradiation device including a light source unit having a light source, the light source unit configured to irradiate a reflection side of the white reference board from only one oblique direction; an image sensor configured to detect reflected light from the white reference board; and a determination device configured to determine if an attached substance exists on the white reference board based on the reflected light detected by the image sensor. The irradiation device includes a reflection board configured to rotate and to focus the light from the light source by its rotation and reflect the focused light onto a manuscript.