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: A display management system including an apparatus executing specified functions; and a server connected communicatably with the apparatus, wherein the apparatus including: a display section; and a detecting section detecting a depressed position on a screen of the display section, wherein the server sends to the apparatus a display data of an operation screen for displaying; the apparatus receives the display data, displays the operation screen in conformance to the display data on the display section, and sends to the server a coordinate information indicating the depressed position detected by the detecting section during the display of the operation screen; the server receives the coordinate information, specifies an operation button corresponding to the coordinate information, and sends an instruction to execute the function assigned to the operation button to the apparatus; and the apparatus receives an execution instruction and executes the function specified by the execution instruction.

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: 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: 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: In a fixing device of an image forming apparatus including a heating roller and a temperature detecting device spaced apart from the roller, having a first sensor for detecting the surface temperature of the roller, and a second sensor for detecting the ambient temperature, the first sensor being placed at a first position in a casing having an opening through which the heat radiation of the roller is directly incident and the second sensor being enclosed by the casing and placed at a second position to which the heat radiation of the roller is not directly incident, the temperature is calculated on the basis of the outputs of the two sensors, and the opening is disposed so as not to enter a region between the vertical plane containing the central axis of the roller and a tangential plane to the circumferential surface of the roller parallel to the vertical plane.

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: 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 a duplex image-forming apparatus having a function of forming images onto both sides of a transfer material. The apparatus includes an image-forming section to respectively form an obverse-side image and a reverse-side image on a photoreceptor element by scanning a light beam, modulated with image signals based on pixel-clock signals and reflected from a polygon mirror rotating at an operating velocity based on polygon-clock signals; a transferring section to transfer said obverse-side image and said reverse-side image onto both surfaces of said recording sheet; a fixing section to fix the images onto both surfaces of said recording sheet; and a clock-frequency changing section to change a pixel-clock frequency, and a polygon-clock frequency, corresponding to a degree of shrinkage of said recording sheet caused by a fixing operation performed in said fixing section, at a transition time of an image-forming operation from one side to another side.

Abstract: An image forming apparatus includes: a photosensitive member; an intermediate transferring member to which an image formed on the photosensitive member is transferred; a press/release operation controlling section for controlling a pressing of the intermediate transferring member to the photosensitive member and for controlling a release of the pressing; a rotational actuation controlling section for controlling a rotational actuation of the photosensitive member; a judging section for judging a finish of a pressing operation carried out by the press/release operation controlling section; and a start timing controlling section for starting a control for the rotational actuation of the photosensitive member when the judging section judges the finish of the pressing operation by the rotational actuation controlling section.

Abstract: In a fixing device of an image forming apparatus including a heating roller and a temperature detecting device spaced apart from the roller, having a first sensor for detecting the surface temperature of the roller, and a second sensor for detecting the ambient temperature, the first sensor being placed at a first position in a casing having an opening through which the heat radiation of the roller is directly incident and the second sensor being enclosed by the casing and placed at a second position to which the heat radiation of the roller is not directly incident, the temperature is calculated on the basis of the outputs of the two sensors, and the opening is disposed so as not to enter a region between the vertical plane containing the central axis of the roller and a tangential plane to the circumferential surface of the roller parallel to the vertical plane.

Abstract: The invention concerns an improvement of a drive system of a color image forming apparatus. The color image-forming apparatus includes a plurality of image-forming elements; a plurality of first driving motors, each of which corresponds to each of the image-forming elements, to drive the plurality of image-forming elements; an intermediate transfer element that is disposed opposite the plurality of image-forming elements; a second driving motor to drive the intermediate transfer element; and a controlling section to control the plurality of first driving motors and the second driving motor. In the color image-forming apparatus, the controlling section controls the plurality of first driving motors and the second driving motor independently of each other, so that a first peripheral speed of each of the image-forming elements coincides with a second peripheral speed of the intermediate transfer element.

Abstract: There is described a method of controlling the rotational peripheral speed of the rotating photoreceptor drum to make it constant. The method includes the steps of: detecting angular velocity signals by means of angular velocity detecting device disposed on an axis of the photoreceptor drum; finding deviations from a reference angular velocity, based on the angular velocity signals; storing a profile of the deviations within a one-revolution of the photoreceptor drum in a storage section, while revising the profile in real-time base; applying an arithmetic processing to an angular velocity signal detected at a current rotational-position of the photoreceptor drum by referring data included in the profile obtained in a preceding one-revolution of the photoreceptor drum; and controlling the motor, based on results of the arithmetic processing for the angular velocity signals, so as to compress the deviations from the reference angular velocity as small as possible.

Abstract: An image forming apparatus comprises: a photosensitive member; an intermediate transferring member to which an image formed on the photosensitive member is transferred; a press/release operation controlling section for controlling a pressing of the intermediate transferring member to the photosensitive member and for controlling a release of the pressing; a rotational actuation controlling section for controlling a rotational actuation of the photosensitive member; a judging section for judging a finish of a pressing operation carried out by the press/release operation controlling section; and a start timing controlling section for starting a control for the rotational actuation of the photosensitive member when the judging section judges the finish of the pressing operation by the rotational actuation controlling section.

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 a duplex image-forming apparatus having a function of forming images onto both sides of a transfer material. The apparatus includes an image-forming section to respectively form an obverse-side image and a reverse-side image on a photoreceptor element by scanning a light beam, modulated with image signals based on pixel-clock signals and reflected from a polygon mirror rotating at an operating velocity based on polygon-clock signals; a transferring section to transfer said obverse-side image and said reverse-side image onto both surfaces of said recording sheet; a fixing section to fix the images onto both surfaces of said recording sheet; and a clock-frequency changing section to change a pixel-clock frequency, and a polygon-clock frequency, corresponding to a degree of shrinkage of said recording sheet caused by a fixing operation performed in said fixing section, at a transition time of an image-forming operation from one side to another side.

Abstract: There is described a method of controlling the rotational peripheral speed of the rotating photoreceptor drum to make it constant. The method includes the steps of: detecting angular velocity signals by means of angular velocity detecting device disposed on an axis of the photoreceptor drum; finding deviations from a reference angular velocity, based on the angular velocity signals; storing a profile of the deviations within a one-revolution of the photoreceptor drum in a storage section, while revising the profile in real-time base; applying an arithmetic processing to an angular velocity signal detected at a current rotational-position of the photoreceptor drum by referring data included in the profile obtained in a preceding one-revolution of the photoreceptor drum; and controlling the motor, based on results of the arithmetic processing for the angular velocity signals, so as to compress the deviations from the reference angular velocity as small as possible.

Abstract: The invention concerns an improvement of a drive system of a color image forming apparatus. The color image-forming apparatus includes a plurality of image-forming elements; a plurality of first driving motors, each of which corresponds to each of the image-forming elements, to drive the plurality of image-forming elements; an intermediate transfer element that is disposed opposite the plurality of image-forming elements; a second driving motor to drive the intermediate transfer element; and a controlling section to control the plurality of first driving motors and the second driving motor. In the color image-forming apparatus, the controlling section controls the plurality of first driving motors and the second driving motor independently of each other, so that a first peripheral speed of each of the image-forming elements coincides with a second peripheral speed of the intermediate transfer element.