Abstract: A sheet image scanner of the present invention has plural image sensors to output electric signals by detecting optical image data that are obtained by applying a light from a light source to documents, amplifiers to amplify outputs from the plural image sensors, and a peak detection processing unit to detect a peak value of sensitivity of at least one of the plural image sensors and set a gain value for each of amplifiers for the plural image sensors using the detected peak value.

Abstract: The image reader according to the present invention is able to set the accurate threshold level free of influence of dirt and dust even when the reference “white” level is requested for shading correction during the acceleration while the carriage is being accelerated without increasing the averaging frequency when the reflected light from the white board is read for shading correction. In addition, because the distance between the head end of the transparent glass and the home position as well as the distance between the home position and the reading window are shortened, the size of the image reader is reduced.

Abstract: Disclosed is an image reading apparatus that can change the amounts of light of an exposure lamp at the time of reading a white reference value (shading correction value) and at the time of reading an image, or changing a signal amplification factor of an amplification section for amplifying the output of a CCD line sensor, by using a white-level correction value which has been read at the time of assembling and adjusting the apparatus. This can provide high-quality images without performing complex image processing even if an indicator is placed at such a location where a user is easy to see and use it.

Abstract: In an image-reading apparatus, the size of a document placed at a predetermined position is sensed by a document size sensor, an image is read from the document in the document size sensed, and image data indicative of the read image is subjected to certain processing executed by an image processing section. A power supply section is provided which includes a first power supply which supplies power to the image processing section, and a second power supply which supplies power to the document size sensor. The second power supply is supplied with power from the first power supply and can be turned on and off independently of turn-on and turn-off of the first power supply. A power supply control section is also provided which controls turn-on and turn-off of the second power supply.

Abstract: An image reading device reads an image of an original mounted on an original mounting base by using an optical scanning unit which is subjected to acceleration drive along the original mounting base until a velocity according to a reading magnification is obtained and then scanned by uniform velocity drive. A stepping motor moves the optical scanning unit. A reading magnification acceptance portion accepts a reading magnification of an image of the original mounted on the original mounting base.

Abstract: An image reader of the present invention comprises a fluctuation detector that can be connected to the external equipment by means of an image data input-output section, and can subject image data, continuous in a first direction and outputted as image information on a test chart is photoelectrically converted by means of a CCD sensor when a mirror set or the test chart is moved in the first direction, to Fourier conversion, thereby obtaining the frequency of a fluctuation of the obtained image data and a maximum value of the amplitude thereof. If the obtained maximum value of the fluctuation amplitude is greater than a given value, the fluctuation detector is used to compare the frequency of the fluctuation and the natural frequency of a drive motor for generating driving force for moving the mirror set or the image. If the fluctuation frequency and the natural frequency are not equal, the value of current supplied to the drive motor is increased.

Abstract: The image reader according to the present invention is able to set the accurate threshold level free of influence of dirt and dust even when the reference “white” level is requested for shading correction during the acceleration while the carriage is being accelerated without increasing the averaging frequency when the reflected light from the white board is read for shading correction.

Abstract: The image scanning apparatus capable of reading an image by scanning a carriage equipped with a light source, mirrors and the like in a sub-scanning direction of an original document O, is provided, and in this apparatus, the stepping motor is used to drive the carriage, and an open loop control and switching of the exciter are carried out. With this structure, the scanning speed of the carriage can be increased to be higher than the set speed once, and then reduced to the set speed, thus making it possible to shorten the time for the carriage to move from the home position to the top of the document to be scanned, while suppressing the load on the CPU.