Abstract: An image forming apparatus having a plurality of light sources and printing an image carrier by collectively scanning an image carrier with beams from the plurality of light sources includes a screen processing unit for performing a screen process on input image data and a registration correction processing unit for performing skew correction on the image data on which the screen process has been performed and for performing an image shift process in the sub-scanning direction, which is a moving direction of the image carrier, based on a periodic characteristic of exposure by the collective scanning and the period of the screen by the screen process.

Abstract: An electrophotographic printing apparatus comprises a paper-conveying device conveying a continuous paper sheet in a definite conveyance direction, a plurality of photoreceptors disposed downstream from the paper-conveying device at regular intervals in the conveyance direction of the continuous paper sheet, and one or more idler rollers that are disposed between the paper-conveying device and the most upstream photoreceptor and that rotate passively while contacting the continuous paper sheet wrapping around the rollers. The idler roller that the continuous paper sheet is in contact with at the largest wrap angle has a circumference that is equal to the whole or a fractional length of the interval between the axes of two adjacent photoreceptors.

Abstract: An image forming apparatus has: a recording head having plural unit recording heads divided in a direction orthogonal to a moving direction of a recording medium; a detecting section detecting at least offset of an image recorded by a vicinity of an end portion, in the direction orthogonal to the moving direction of the recording medium, of the plural unit recording heads; and a correcting section correcting recording offset of the recording head on the basis of results of detection of the detecting section.

Abstract: Provided is an inkjet recording device that has a conveying unit for conveying a recording medium, plural recording head groups each structured by plural unit heads disposed along the conveying direction, and an ink receiving unit for receiving ink discharged from the unit heads. The recording head groups, correspond respectively to plural individual recording regions which are sectioned off in the recording medium transverse direction which is orthogonal to the conveying direction, are disposed so as to be at respectively different positions at adjacent individual recording regions along the conveying direction. The ink receiving unit is disposed so as to face ink drop discharging surfaces of the unit heads. The conveying unit is plural conveying belts disposed at positions evading trajectories of the ink drops from the unit heads as seen in a direction of a line normal to the recording medium so as to be divided in the conveying direction.

Abstract: An image forming apparatus has a plurality of image forming units for forming images in various colors, and transfers images formed by these image forming units onto a transfer belt an overlapping manner. The image forming apparatus includes a control unit for outputting a predetermined control signal in order to form a color-shift detecting pattern with respect to the transfer belt by employing a plurality of these image forming units, and a pattern detecting sensor for reading the color-shift detecting pattern formed on the transfer belt by this control unit. Under normal operation, the control unit controls forming operation of color-shift detecting patterns by using only commonly-used color image forming units, while the control unit does not form a color-shift detecting pattern by using a specific-color image forming unit.

Abstract: An image forming apparatus has a plurality of image forming units for forming images in various colors, and transfers images formed by these image forming units onto a transfer belt an overlapping manner. The image forming apparatus includes a control unit for outputting a predetermined control signal in order to form a color-shift detecting pattern with respect to the transfer belt by employing a plurality of these image forming units, and a pattern detecting sensor for reading the color-shift detecting pattern formed on the transfer belt by this control unit. Under normal operation, the control unit controls forming operation of color-shift detecting patterns by using only commonly-used color image forming units, while the control unit does not form a color-shift detecting pattern by using a specific-color image forming unit.

Abstract: An image-forming apparatus adjusts the running state of a belt by displacing one of the rolls supporting an endless belt, wherein the roll is displaced to prevent the belt from being twisted by a change in the tension of the endless belt that stems from the operation for displacing the roll. When the image-forming apparatus is provided with a belt running adjusting mechanism 20 which adjusts the running state of the endless belt 21 by displacing one (drive roll 22) of plural rolls supporting the belt 21 in the adjusting directions J, K, there is provided a tension correction mechanism 60 which corrects a change in the tension of the endless belt 21 that is caused by the operation of the belt running adjusting mechanism 20 for displacing the roll 22, by displacing, in the correction directions L, M, a contact member (tension roll 25) which is in contact with the belt 21 along the direction of width thereof.

Abstract: A registration pattern is formed on an intermediate transfer belt by using one photosensitive body. Pattern parts transferred onto the intermediate transfer belt vary in spacing due to speed variation occurring at the transfer time. The passing timing of the registration pattern is read through a read section placed downstream from the photosensitive body and speed (position) variation is sensed. The sense data is gotten over several cycles of the intermediate transfer belt and a low-frequency component caused by thickness unevenness of the intermediate transfer belt is extracted. The extracted data is subjected to the effects of variations at both the formation time and read time of the registration pattern and thus is corrected of calculating true speed (position) variation data. For example, a drive roll is controlled based on the data and an image is formed.

Abstract: An imperfect register correcting method is applied to correcting the incorrect disposition and functions of the components of a multicolor image forming apparatus which forms a multicolor image by sequentially superposing color images formed by a plurality of image forming units thereof, causing imperfect register of the color images formed by the plurality of image forming units. The imperfect register correcting method comprises a first imperfect register correcting cycle in which skews of the image forming units are corrected, and a second imperfect register correcting cycle in which factors of imperfect register other than the skews are corrected. The second imperfect correcting cycle is carried out subsequent to the first imperfect register correcting cycle to obviate the introduction of errors into data for correcting the factors of imperfect register by the correction of the skew of the image forming units.