Abstract: A color image forming apparatus for forming a color image on a recording medium, includes: an image carrier; a polygon mirror; a signal forming device for forming a pseudo main scanning reference signal having a fixed cycle; and a controller for controlling image formation on a predetermined surface of the recording medium on the basis of the pseudo main scanning reference signal formed by the signal forming device and a main scanning reference signal which is formed by detecting a light beam that is scanned by the polygon mirror.

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 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 forming apparatus including: a registration section which registers information on a diagnostic mode, where an operation mode to diagnose inside the image forming apparatus based on error information is assumed to be the diagnostic mode; an error detecting section which detects an error in the apparatus and outputs error information; and a control section which, when the error detecting section outputs error information, receives the information on the diagnostic mode corresponding to the error information from the registration section, and executes problem solution and recovery of the apparatus.

Abstract: A laser scanning apparatus includes: a plurality of laser light sources including a first laser light source and a second laser light source; a scanner for scanning laser lights emitted from the plurality of laser light sources in a main scanning direction; a light receiving sensor for receiving the laser lights deflected and scanned by the scanner; and a signal generation unit for generating a first signal which is in synchronization with a pixel clock for the second laser light source based on an output from the light receiving sensor obtained by a laser light emitted from the first laser light source, and for generating a second signal which is in synchronization with a pixel clock for the first laser light source based on an output from the light receiving sensor obtained by a laser light emitted from the second laser light source.

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: An image forming apparatus for forming color images comprising at least two or more colors, having a function of magnification correction of image size by one page unit, the image forming apparatus including: an image carrier; a polygonal mirror rotator independently provided for each color; and a controller which simultaneously conducts first control for changing rotation speed of the polygonal mirror rotator in order for changing image size in a sub-scanning direction perpendicular to a main scanning direction, and second control for correcting a correction amount for color registration error depending on magnification correction of image size, and for adjusting a rotating phase of the polygonal mirror rotator depending on the corrected correction amount for color registration error.

Abstract: A laser scanning apparatus includes: a plurality of laser light sources including a first laser light source and a second laser light source; a scanner for scanning laser lights emitted from the plurality of laser light sources in a main scanning direction; a light receiving sensor for receiving the laser lights deflected and scanned by the scanner; and a signal generation unit for generating a first signal which is in synchronization with a pixel clock for the second laser light source based on an output from the light receiving sensor obtained by a laser light emitted from the first laser light source, and for generating a second signal which is in synchronization with a pixel clock for the first laser light source based on an output from the light receiving sensor obtained by a laser light emitted from the second laser light source.

Abstract: There is provided a controller that controls and drives the polygon mirror to a target speed with keeping a predetermined phase. When the controller controls the speed of the polygon mirror along with the image magnification adjustment, the controller controls the polygon mirror with a waiting time t1 from an end of the speed control of the polygon mirror for stabilizing before the phase control and a waiting time t2 from an end of the phase control of the polygon mirror for stabilizing, the t1 and t2 being set with a relation of t1<t2.

Abstract: There is described a signal controlling circuit particularly used in a printer or copier. The circuit includes a delay chain section to generate a plurality of delayed clock signals, a synchronized signal detecting section to detect a number of delay stages, a total delay time of which is equivalent to a single period of the reference clock signal, based on delayed clock signals synchronized with an index signal and are selected from the plurality of delayed clock signals, an index signal counting section to count index signals inputted into the index signal counting section, a phase shift calculating section to calculate a phase shift amount in respect to the reference clock signal, and a delayed clock selecting section to select a specific delayed clock signal out of the plurality of delayed clock signals in an alternative way, so as to output the specific delayed clock signal to an external section.

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: There is provided a controller that controls and drives the polygon mirror to a target speed with keeping a predetermined phase. When the controller controls the speed of the polygon mirror along with the image magnification adjustment, the controller controls the polygon mirror with a waiting time t1 from an end of the speed control of the polygon mirror for stabilizing before the phase control and a waiting time t2 from an end of the phase control of the polygon mirror for stabilizing, the t1 and t2 being set with a relation of t1<t2.

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: A color image forming apparatus for forming a color image on a recording medium, includes: an image carrier; a polygon mirror; a signal forming device for forming a pseudo main scanning reference signal having a fixed cycle; and a controller for controlling image formation on a predetermined surface of the recording medium on the basis of the pseudo main scanning reference signal formed by the signal forming device and a main scanning reference signal which is formed by detecting a light beam that is scanned by the polygon mirror.

Abstract: An image forming apparatus comprising an image forming apparatus for forming an image on paper, based on image data stored in storage means; a color display section for displaying a thumbnail image, based on said image data stored in storage means; a setting section for setting in such a way that a thumbnail image is displayed on said color display section; and control means for controlling the display on said color display unit; wherein said control means is set by said setting section in such a way that a thumbnail image is displayed, and color depth is switched if the color thumbnail image is to be displayed on said color display unit.

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: 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.