Abstract: An image reader includes a first image reading unit that reads first image data by scanning one surface of a document at a first resolution corresponding to a magnification ratio and a predetermined first scan cycle; and a second image reading unit that accumulates light radiated from a light source and reads second image data by scanning other surface of the document at a fixed second resolution and a second scan cycle corresponding to the magnification ratio, wherein the second image reading unit controls light accumulation time of the light radiated from the light source to be constant.

Abstract: An image reader capable of entering a power save mode for saving power consumption during standby includes: a gain amplifier; a reference white plate that is to be scanned when gain control of the gain amplifier is performed to obtain a controlled gain value; a carriage that moves to an stops at an area corresponding to the reference white plate when the image reader enters the power save mode; a gain storage section that stores the controlled gain value as a recovery parameter when the image reader enters the power save mode; and a gain setting section that sets the recovery parameter as the controlled gain value when the image reader exits the power save mode.

Abstract: An image reader capable of entering a power save mode for saving power consumption during standby includes: a gain amplifier; a reference white plate that is to be scanned when gain control of the gain amplifier is performed to obtain a controlled gain value; a carriage that moves to an stops at an area corresponding to the reference white plate when the image reader enters the power save mode; a gain storage section that stores the controlled gain value as a recovery parameter when the image reader enters the power save mode; and a gain setting section that sets the recovery parameter as the controlled gain value when the image reader exits the power save mode.

Abstract: An image reader includes a first image reading unit that reads first image data by scanning one surface of a document at a first resolution corresponding to a magnification ratio and a predetermined first scan cycle; and a second image reading unit that accumulates light radiated from a light source and reads second image data by scanning other surface of the document at a fixed second resolution and a second scan cycle corresponding to the magnification ratio, wherein the second image reading unit controls light accumulation time of the light radiated from the light source to be constant.

Abstract: A level detecting part detects image data levels for the respective output directions of the first half and the second half to be used for the linearity correction, which image data levels correspond to image data around a connection point between the first half and the second half and are obtained from respective combinations for the respective output directions of the first half and the second half. A calculating part calculates linearity correction values or correction value calculating parameters from the detected image data levels for any one of the first half and the second half; and a defect detection part detecting a defect in the image data levels thus detected around the connection point are provided.

Abstract: An offset adjusting device includes a sample-hold unit that sample-holds an analog image signal obtained by converting reflected light from an original into an electric signal with a photoelectric conversion device to thereby obtain a sample-hold signal; an amplifying unit that amplifies the sample-hold signal to obtain an amplified signal; an analog-digital converter that digitizes the amplified signal to obtain a digital signal; a difference detecting unit that detects a difference between a black-level detection value of the digital signal and a black-level target value; an selecting unit that selects an adjustment coefficient among a plurality of adjustment coefficients based on comparison of the difference and a reference value; and a feedback unit that subjects an offset adjustment value based on the adjustment coefficient selected by the selecting unit to feedback processing.

Abstract: An image reading apparatus, including an image sensor configured to receive light and output an image signal in accordance with image data carried in the light, an A/D converter configure to convert the image signal into a digital signal with reference to a reference voltage, and a reference white plate configured to be read so as to generate density data. Also included is a correction device configured to correct the digital signal in accordance with shading data, a reference member configured to define a readable density limit, and a detection device configured to detect a ratio of density of the reference white plate to that of the reference member as density adjustment data. The density is obtained by reading the respective reference member and reference white plate in substantially a same exposure condition. Further included is a control device configured to control the correction device to adjust the digital signal in accordance with the density adjustment data.

Abstract: An image reading device includes a photoelectric device provided with an empty transfer part. An A-D converter performing A-D conversion on an output signal for each pixel of the photoelectric device. A reference voltage varying part varies a reference voltage of the A-D converter. A detecting part detects a black correction reference data output from each pixel of the photoelectric device. A black shading correcting part subtracts the black correction reference data from digital image data obtained from the output signal for each pixel of the photoelectric device when an image is read by the A-D converter having the reference voltage set therein. And, a correcting part corrects the black correction reference data by a ratio of an output level of the empty transfer part obtained through the A-D converter when the black correction reference data is detected and an output level of the empty transfer part obtained through the A-D converter when the image is read.

Abstract: An offset adjusting device includes a sample-hold unit that sample-holds an analog image signal obtained by converting reflected light from an original into an electric signal with a photoelectric conversion device to thereby obtain a sample-hold signal; an amplifying unit that amplifies the sample-hold signal to obtain an amplified signal; an analog-digital converter that digitizes the amplified signal to obtain a digital signal; a difference detecting unit that detects a difference between a black-level detection value of the digital signal and a black-level target value; an selecting unit that selects an adjustment coefficient among a plurality of adjustment coefficients based on comparison of the difference and a reference value; and a feedback unit that subjects an offset adjustment value based on the adjustment coefficient selected by the selecting unit to feedback processing.

Abstract: A level detecting part detects image data levels for the respective output directions of the first half and the second half to be used for the linearity correction, which image data levels correspond to image data around a connection point between the first half and the second half and are obtained from respective combinations for the respective output directions of the first half and the second half. A calculating part calculates linearity correction values or correction value calculating parameters from the detected image data levels for any one of the first half and the second half; and a defect detection part detecting a defect in the image data levels thus detected around the connection point are provided.

Abstract: A method of correcting information scanned by an image scanner includes scanning a first number of positions of a first portion of a correction member having different reflectances to obtain first data. A second number of positions of a second portion of the correction member having different reflectances are scanned to obtain second data. The first data is transformed to obtain transformed first data. The second data is transformed to obtain transformed second data. A table that includes relationships between reflectances and differences of the transformed first data and the transformed second data is generated for a third number of positions greater than each of the first number of positions and the second number of positions.

Abstract: An image reading apparatus, including an image sensor configured to receive light and output an image signal in accordance with image data carried in the light, an A/D converter configure to convert the image signal into a digital signal with reference to a reference voltage, and a reference white plate configured to be read so as to generate density data. Also included is a correction device configured to correct the digital signal in accordance with shading data, a reference member configured to define a readable density limit, and a detection device configured to detect a ratio of density of the reference white plate to that of the reference member as density adjustment data. The density is obtained by reading the respective reference member and reference white plate in substantially a same exposure condition. Further included is a control device configured to control the correction device to adjust the digital signal in accordance with the density adjustment data.

Abstract: An image reading device includes a photoelectric device provided with an empty transfer part; an A-D converter performing A-D conversion on an output signal for each pixel of the photoelectric device; a reference voltage varying part varying a reference voltage of the A-D converter; a detecting part detecting a black correction reference data from output for each pixel of the photoelectric device; a black shading correcting part subtracting the black correction reference data from digital image data obtained from the output signal for each pixel of the photoelectric device when an image is read by the A-D converter having the reference voltage set therein; and a correcting part correcting the black correction reference data by a ratio of an output level of the empty transfer part obtained through the A-D converter when the black correction reference data is detected and an output level of the empty transfer part obtained through the A-D converter when the image is read.