Abstract: The residual potential and charging potential of the surface of a photosensitive drum 20, or the charging potential and exposure potential of the surface of the photosensitive drum 20 are detected by an exposure sensor 28. The lifetime of the photosensitive drum 20 is judged in accordance with the difference between the detected charging potential and residual potential, or the difference between the detected charging potential and exposure potential.

Abstract: The residual potential and charging potential of the surface of a photosensitive drum 20, or the charging potential and exposure potential of the surface of the photosensitive drum 20 are detected by an exposure sensor 28. The lifetime of the photosensitive drum 20 is judged in accordance with the difference between the detected charging potential and residual potential, or the difference between the detected charging potential and exposure potential.

Abstract: Methods and apparatus for color signal compensation are disclosed. A quality of one type of signal is enhanced using a second type of signal, wherein the second type of signal has a higher quality than that of the unenhanced first type of signal. This may be used in an image forming apparatus for scanning a color image, and using higher-resolution monochrome signals to enhance the resolution of lower-resolution color signals.

Abstract: There is disclosed an image reading apparatus having an image sensor unit. The image sensor unit may include a number of photodiode arrays. The photodiode arrays may have different qualities and the output of the photodiode arrays may be processed differently. Output of the photodiode arrays may be mixed to improve image qualities.

Abstract: An apparatus and method for processing image data includes generating color image data and monochrome image data from an original image, the color image data and the monochrome image data having a first resolution, the color image data including RGB data. Multiples of pixels of the color image data are averaged such that the averaged pixel data has a second resolution lower than the first resolution based on the multiples. Color difference data is generated using the averaged pixel data, and compensated color image data is generated having the first resolution based on the color difference data and the monochrome image data.

Abstract: Periodically, the dark attenuation characteristic of the electric potential on the surface of the photo conductor drum 20 is detected. Then, the target value ?Vgt of the grid bias voltage ?Vg of the charging unit 24 necessary for maintaining the charged electric potential ?Vod of the developing position of the surface of the photo conductor drum 20 at the set value ?Vods is detected from the above detected dark attenuation characteristic. At image formation where the developing unit 24 works, the value of the grid bias voltage ?Vg of the charging unit 24 is set at the above detected target value ?Vgt.

Abstract: The residual potential and charging potential of the surface of a photosensitive drum 20, or the charging potential and exposure potential of the surface of the photosensitive drum 20 are detected by an exposure sensor 28. The lifetime of the photosensitive drum 20 is judged in accordance with the difference between the detected charging potential and residual potential, or the difference between the detected charging potential and exposure potential.

Abstract: Methods and apparatus for color signal compensation are disclosed. A quality of one type of signal is enhanced using a second type of signal, wherein the second type of signal has a higher quality than that of the unenhanced first type of signal. This may be used in an image forming apparatus for scanning a color image, and using higher-resolution monochrome signals to enhance the resolution of lower-resolution color signals.

Abstract: A data transmission apparatus and the like are provided which, in sending data of a large capacity such as still image data, can significantly reduce an amount of transmission data while suppressing deterioration of the data. The transmission apparatus of the present invention include: a differential data calculation section for, assuming that data to be a reference is reference data and data to be compared with the reference data is object data, comparing the reference data and the object data to calculate a difference between both the data as differential data; a differential data amount reduction section for reducing a transmission data amount of the differential data obtained by the differential data calculation section such that the differential data can be restored; and a data transmission section for sending the differential data with its data amount reduced by the differential data amount reduction section.

Abstract: There is disclosed an image reading apparatus having an image sensor unit. The image sensor unit may include a number of photodiode arrays. The photodiode arrays may have different qualities and the output of the photodiode arrays may be processed differently. Output of the photodiode arrays may be mixed to improve image qualities.

Abstract: There is disclosed an image reading apparatus having an image sensor unit. The image sensor unit may include a number of photodiode arrays. The photodiode arrays may have different qualities and the output of the photodiode arrays may be processed differently. Output of the photodiode arrays may be mixed to improve image qualities.

Abstract: A data transmission apparatus and the like are provided which, in sending data of a large capacity such as still image data, can significantly reduce an amount of transmission data while suppressing deterioration of the data. The transmission apparatus of the present invention include: a differential data calculation section for, assuming that data to be a reference is reference data and data to be compared with the reference data is object data, comparing the reference data and the object data to calculate a difference between both the data as differential data; a differential data amount reduction section for reducing a transmission data amount of the differential data obtained by the differential data calculation section such that the differential data can be restored; and a data transmission section for sending the differential data with its data amount reduced by the differential data amount reduction section.

Abstract: Methods and apparatus for color signal compensation are disclosed. A quality of one type of signal is enhanced using a second type of signal, wherein the second type of signal has a higher quality than that of the unenhanced first type of signal. This may be used in an image forming apparatus for scanning a color image, and using higher-resolution monochrome signals to enhance the resolution of lower-resolution color signals.

Abstract: A color image reader according to the present invention has a reading object holder which is plate shape and which can transmit light and holds the subject to be read, a lighting device for illuminating the subject to be read on the reading object holder a reducing lens for providing convergence to the image light from the reading object, a 3-line CCD sensor for receiving the image light with convergence given by the reducing lens and outputting three electrical signals corresponding to the image light, and a lateral chromatic aberration correction circuit for designating one output signal of the three output signals outputted from the 3-line CCD sensor to the reference, comparing the two remaining output signals with the output signal used for the reference, and providing a predetermined correction to the two remaining output signals, and can suppress generation of image color deviation which depends on the distance between the 3-line CCD sensor and the optical axis of the reducing lens.

Abstract: In a method for diagnosing an optical device, the positions of intersections between a scanning line and the line segments of an adjustment mark provided in a predetermined position, and output levels at the intersections are detected on the basis of the output characteristic of an output level corresponding to each pixel position and obtained by reading the adjustment mark along the scanning line. The detected output levels are compared with a predetermined value to detect an error due to the attachment position of the optical device.

Abstract: A reference chart including a plurality of patterns for sampling each of characteristic quantities indicating characteristics of a defective image is read by an image scanner targeted for checking, and image data is stored in a memory. An image analyzing section samples the characteristic quantity of each of the plurality of patterns expressed in the image data. Sampling of the characteristic quantities is hardly affected by a displacement between ideal image data and the above stored image data. A correlation table holding section holds a correlation table which associates each phenomenon name for classifying defective image and at lest one of the characteristics quantities corresponding to the phenomenon name. Referring to the correlation table, a phenomenon name specifying section specifies a phenomenon name of a pattern region in which the characteristic quantity is sampled by the characteristic quantity sampling section from among the plurality of patterns expressed in the image data.

Abstract: A scanner unit as an image read-out apparatus has a document glass on which a document is placed, an exposure lamp for illuminating the document with light, a CCD line sensor for receiving reflected flight from the document and converting the light to electric signal, first to third mirrors for conducing the reflected light from the document to the CCD sensor and a light condensing lens for allowing the reflected light which is conducted through the first to the third mirrors to condense on the CCD line sensor. In a position away from a document effective area at which the document is set on a document glass a chart is printed or attached to allow diagnosis to be made for the “displacements” of scanner unit's respective constituent elements, that is, optical members such as the exposure lamp, first to third mirrors, lens and CCD line sensor.