Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is represented by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted.

Abstract: An image forming apparatus including a plurality of image forming sections arranged in tandem for forming an image having a plurality of colors, the image forming apparatus having: an image reading section for reading an image of a document; an exposure unit having each color exposure section for conducting each color exposure for writing the image, a process unit having a plurality of image forming sections for forming a toner image based on the image read by the image reading section; and a casing for accommodating the image reading section, the exposure unit and the process unit, wherein the exposure unit and the process unit are integrated as an image forming unit and the image forming unit is structured so that it can be drawn from the casing.

Abstract: In an image forming apparatus having a process correction mode wherein when a temperature of a fixing device in an image formation system in a power-on state is equal to or less than a predetermined value, the image forming apparatus makes the fixing temperature to increase to the predetermined value. The apparatus sets the process correction mode based on power-on information output from a first detector which detects presence of the power-on state for the fixing device and fixing temperature information output from a second detector which detects a fixing temperature in the fixing device, and sets a priority level for performing the correction processing of the color misregistration to be lower than the correction processing of the process other than the correction processing of color the misregistration.

Abstract: An image printing apparatus includes a control unit which controls a rotational speed of an image carrier; a detecting unit which detects data of the rotational speed; a storage unit which stores the rotational speeds up to n past rotation cycle of said image carrier; and a determining unit which determines whether a rotational speed difference between a latest rotational speed in a current rotation cycle and a rotational speed in n past rotation cycle before the current rotation cycle at a predetermined interval, which includes the same rotational position in respective rotation cycles and its near position, is more than a predetermined reference value, wherein said control unit controls the rotational speed of said image carrier by using the data of rotational speeds at a predetermined interval including the same rotational position in one or n past rotation cycle before the current rotation cycle, and further said control unit controls a rotational speed in a subsequent rotation cycle next to the current r

Abstract: A color image forming apparatus including: an image forming section which forms an image based on image information on an image carrier provided in the image forming section; a detection section which detects a print mark for color misalignment correction formed on the image carrier by the image forming section, and outputs print mark detection information; and a control section for executing color misalignment correction control based on the print mark detection information outputted from the detection section, wherein, the control section obtains a trend of a color misalignment amount of the print mark by statistically processing data of the result of the print mark detection, calculates an execution timing of color misalignment correction base on the obtained trend, and executes the color misalignment correction at the calculated execution timing.

Abstract: When conducting a color-shift-correcting mode using a registration mark formed by the image forming section on an image carrier, the image detecting section outputs the image detection signal representing the line width of the registration mark and the control section calculates the line width of the registration mark from the image detection signal. The control section compares a line width of the registration mark with a predetermined reference value of the line width to discriminate between abnormality and normality. If normality, the control section continues the color-shift-correcting mode and if abnormality the control section conducts the image forming system restoration mode after stopping the execution of the color-shift-correcting mode. Therefore, even in the case where a white spot is generated for some reasons on the registration mark, the color-shift-correcting mode can be conducted on the normal registration mark with the help of the image forming system restoration mode.

Abstract: An image forming apparatus having a rotation body which is used for transferring an image, a drive section which rotates the rotation body, and a control section which sends a control signal to the drive section to control a speed of the rotation body, the image forming apparatus including: a test signal generating section which generates a test signal and adds it to the control signal; an angular velocity detecting section which detects an angular velocity of the rotation body; and a transfer function calculating section which obtains a latest transfer function of a rotation system including the rotation body and drive section, based on the angular velocity detected by the angular velocity detecting section and the test signal generated by the test signal generating section, wherein the control section controls the drive section, based on the latest transfer function obtained by the transfer function calculating section.

Abstract: A tandem type color image forming apparatus which executes color misregistration correction, including: a detecting section which detects a width of a transfer sheet; an image forming section having an image carrier, on which arranged side by side are an image area where formed is an image for transfer and a non-image area where formed is the imprint image; and a control section which selects a complex or a single correction mode based on the transfer sheet width, to execute correction processing; where the complex correction mode is an operation mode of forming in parallel the image for transfer in the image area and the imprint image in the non-image area, and the single correction mode is an operation mode of suspending to form the image for transfer in the image area, and executing only to form the imprint image in the non-image area or in the image area.

Abstract: An image printing apparatus includes a control unit which controls a rotational speed of an image carrier; a detecting unit which detects data of the rotational speed; a storage unit which stores the rotational speeds up to n past rotation cycle of said image carrier; and a determining unit which determines whether a rotational speed difference between a latest rotational speed in a current rotation cycle and a rotational speed in n past rotation cycle before the current rotation cycle at a predetermined interval, which includes the same rotational position in respective rotation cycles and its near position, is more than a predetermined reference value, wherein said control unit controls the rotational speed of said image carrier by using the data of rotational speeds at a predetermined interval including the same rotational position in one or n past rotation cycle before the current rotation cycle, and further said control unit controls a rotational speed in a subsequent rotation cycle next to the current r

Abstract: An image printing apparatus includes a control unit which controls a rotational speed of an image carrier; a detecting unit which detects data of the rotational speed; a storage unit which stores the rotational speeds up to n past rotation cycle of said image carrier; and a determining unit which determines whether a rotational speed difference between a latest rotational speed in a current rotation cycle and a rotational speed in n past rotation cycle before the current rotation cycle at a predetermined interval, which includes the same rotational position in respective rotation cycles and its near position, is more than a predetermined reference value, wherein said control unit controls the rotational speed of said image carrier by using the data of rotational speeds at a predetermined interval including the same rotational position in one or n past rotation cycle before the current rotation cycle, and further said control unit controls a rotational speed in a subsequent rotation cycle next to the current r

Abstract: A signal processing apparatus comprising: an optical sensor for outputting a detection signal by detecting a surface of a recording medium on which a correction image is to be formed; and a control section configured to obtain a detection signal of the surface of the recording medium with the correction image from which a dominant frequency component has been deleted by making reverse frequency analysis of an analysis signal that has been obtained by making a frequency analysis of a detection signal outputted by the optical sensor detecting the surface of the recording medium on which the correction image it formed.

Abstract: In a document reading apparatus having a scanning exposure reading system by which a document placed on a platen is scanning exposed by an optical system and a document image is read out, or a document reading system by which a moving document is read out by an optical system, at the first collection position and the second collection position which are different in the sub-scanning direction of the scanning expose on a reference density plate, the first shading correction data and the second shading correction data are respectively read in the main scanning direction, and the shading position is corrected on the basis of the read first and second shading correction data.

Abstract: An image printing apparatus includes a control unit which controls a rotational speed of an image carrier; a detecting unit which detects data of the rotational speed; a storage unit which stores the rotational speeds up to n past rotation cycle of said image carrier; and a determining unit which determines whether a rotational speed difference between a latest rotational speed in a current rotation cycle and a rotational speed in n past rotation cycle before the current rotation cycle at a predetermined interval, which includes the same rotational position in respective rotation cycles and its near position, is more than a predetermined reference value, wherein said control unit controls the rotational speed of said image carrier by using the data of rotational speeds at a predetermined interval including the same rotational position in one or n past rotation cycle before the current rotation cycle, and further said control unit controls a rotational speed in a subsequent rotation cycle next to the current r

Abstract: The invention concerns an image-forming apparatus employing a clock-generating circuit, which generates dot clock pulses utilized for an image-writing section of the image-forming apparatus. The clock-generating circuit includes a digital-delay dot clock adjusting section to generate first dot clock pulses having a predetermined number of pulses within a predetermined time interval at a constant exposing range of the image-writing section, wherein each period of the first dot clock pulses is slightly increased or reduced by changing a selection for a plurality of delayed clock pulses, which are generated by delaying clock-pulses, outputted from a reference oscillator, in slightly different delay times; and a jitter suppressing section to suppress a jitter component included in the first dot clock pulses, wherein the jitter suppressing section divides the first dot clock pulses to generate second dot clock pulses, and then, multiplies the second dot clock pulses to generate the dot clock pulses.

Abstract: When conducting a color-shift-correcting mode using a registration mark formed by the image forming means on an image carrier, the image detecting means outputs the image detection signal representing the line width of the registration mark and the control section calculates the line width of the registration from the image detection signal. The control means compares a line width of the registration mark with a predetermined reference value of the line width to discriminate between abnormality and normality. If normality, the control means continues the color-shift-correcting mode and if abnormality the control means conducts the image forming system restoration mode after stopping the execution of the color-shift-correcting mode. Therefore, even in the case where a white spot is generated for some reasons on the registration mark, the color-shift-correcting mode can be conducted on the normal registration mark with the help of the image forming system restoration mode.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is representing by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is represented by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted.

Abstract: There is described an image-forming apparatus having a rotation system constituted by a driving roller, a driven roller and a transfer belt, threaded on both the driving roller and the driven roller. The apparatus includes: a motor to drive the rotation system, a rotational axis of the motor being coupled to the driving roller directly or through a power transmission element disposed between them; a first rotational-velocity controlling section to control a first rotational velocity of the motor; a velocity detecting section to detect a second rotational velocity of the driving roller or the driven roller; and a second rotational-velocity controlling section to also control the first rotational velocity of the motor, based on a detected signal detected by the velocity detecting section. The second rotational-velocity controlling section employs either a feedback controlling method or a feed-forward controlling method to control the first rotational velocity.

Abstract: In an image forming apparatus for forming a color image by superposing component color images, a control device obtains position data representing a forming position of each of plural registration mark images for the component color images with respect to a positional reference value arbitrarily determined, divides the position data into each of a unit reference range representing a range in which one mark image is formed, converts the position data divided for each unit reference range into those based on respective reference values representing the front edge of the unit reference ranges, extracts the position data representing ranges common to the mutually overlapping ranges each of which is represented by a couple of position data corresponding to the rising and falling edges of a passage timing pulse as read position data of the mark image of the component color, and calculates the amounts of positional deviations of the component color images from one another on the basis of the position data extracted.

Abstract: There is described an image-forming apparatus having a rotation system constituted by a driving roller, a driven roller and a transfer belt, threaded on both the driving roller and the driven roller. The apparatus includes: a motor to drive the rotation system, a rotational axis of the motor being coupled to the driving roller directly or through a power transmission element disposed between them; a first rotational-velocity controlling section to control a first rotational velocity of the motor; a velocity detecting section to detect a second rotational velocity of the driving roller or the driven roller; and a second rotational-velocity controlling section to also control the first rotational velocity of the motor, based on a detected signal detected by the velocity detecting section. The second rotational-velocity controlling section employs either a feedback controlling method or a feed-forward controlling method to control the first rotational velocity.