Abstract: Provided is an image forming apparatus to form an image by scanning with a light beam through a polygon mirror, having a motor drive section to rotate and drive the polygon mirror based on a polygon drive clock pulse and an image processing section capable of adjusting image magnification through image processing, and a control section to control that at least image magnification adjustment by changing revolution of the polygon mirror or image magnification adjustment through the image processing in the image processing section is selected in accordance with an output form of the image when the image magnification is adjusted.

Abstract: Disclosed is an image forming apparatus, which makes it possible to appropriately conduct a controlling operation for eliminating the velocity fluctuation of the photoreceptor drum without generating any malfunction. The apparatus includes a photoreceptor member driven by a motor and a control section that is provided with a feed forward controlling section that stores parameters derived from driving errors for one revolution of the photoreceptor member to create a reverse-phase instruction value based on the parameters and a feedback controlling section that controls a velocity of the photoreceptor member, so as to keep the velocity of the photoreceptor member constant. During an initial operating time, the control section deactivates the feed forward controlling section, while only activates the feedback controlling section to drive the photoreceptor member so as to measure a driving toque of the driving motor, and selects a parameter from the parameters, corresponding to the driving toque measured.

Abstract: An image forming apparatus including: a photoreceptor for bearing a toner image; a transfer body onto which the toner image borne by the photoreceptor is transferred; a drive section for driving the photoreceptor and transfer body respectively, and a control section for controlling the drive section so as to drive the photoreceptor and transfer body at a predetermined driving speed, wherein the control section, under a state in which the control section controls to drive the transfer body at the predetermined driving speed, controls to: a) drive the photoreceptor while changing the driving speed of the photoreceptor within a range of driving speeds between low speed and high speed, including the predetermined driving speed, b) extract torque characteristics under the control which includes the change of driving speed of the photoreceptor, and c) determine the driving speed of the photoreceptor based on the extracted torque characteristics.

Abstract: An image forming apparatus having a color mode and a monochromatic mode, which includes: a transmission member, which can be switched between a transmitted state where a motor transfers a drive force to a single photoreceptor drum and a non-transmitted state where the motor does not transfer the drive force to the single photoreceptor drum; and a controller which switches to the non-transmitted state while executing an image formation in the monochromatic mode, and when a command to execute a next image formation is not instructed, switches to the transmitted state after a phase adjustment of each photoreceptor drum after the image formation in the monochromatic mode, and controls the motor to execute a slight rotation operation at every prescribed period of time by synchronizing plural drums including the single photoreceptor drum with each other through the transmission member.

Abstract: A fixing device includes: a fixing section which passes a sheet through a fixing nip portion formed by a pair of fixing members and thereby fixes a toner image on the sheet by heating; a blowing section which separates the sheet from the fixing members by blowing separation wind from a sheet discharge side of the fixing nip portion to the fixing members; an opening setting section which is provided with an opening region in which an opening width in a sheet width direction is adjustable, and adjusts a blowing range in the sheet width direction of the separation wind blown through the opening range from the blowing section to the fixing members; a temperature detection sensor for detecting temperature of the fixing members; and a control section which controls the opening width of the opening setting section based on the temperature detected of the fixing members.

Abstract: In order that the air surrounding a fixing member is prevented from entering a blowing section for blowing separation air, a wind speed setting section is provided with switchable control modes, namely, a first control mode (control mode for operating the blower fan at a wind speed for separation) and a second control mode (control mode for operating the blower fan at a low speed). This structure allows the blower fan to be controlled in conformity to any one of these first and second control modes.

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: Disclosed is a fixing device, which makes it possible to prevent the air blasting section from deterioration, caused by heat transferred from the duct to the air blasting section. The fixing device includes a fixing section to fix the toner image onto the paper sheet; a heat source; and a separating section to separate the paper sheet from the pair of fixing members. On the other hand, the separating section includes: a gas blasting section to blast a gas; and a duct to guide the gas towards the pair of fixing members, and that is provided with a duct wall serving as a heat receiving surface to receive radiation heat irradiated from the fixing section, and at least one of the gas blasting section and the duct is provided with such a connection structure that suppresses heat transferring action from the duct to the gas blasting section.

Abstract: 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 increases the fixing temperature 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 a correction processing of the color misregistration to be lower than a correction processing comprising an image density adjustment.

Abstract: An image forming apparatus including, a photosensitive body for carrying toner images, a transfer section for nipping the recording sheet at a position facing the photosensitive body and transferring the toner images carried on the photosensitive body onto a recording sheet, a driving section for driving the photosensitive body, and a control section for giving instructions to the driving section to conduct a velocity control to rotate the photosensitive body at a predetermined velocity, wherein the control section sets a gain of velocity control to be greater than normal condition, at a time which is at least one of a time when the recording sheet enters the transfer section, or a time when the recording sheet separates from the transfer section.

Abstract: In an image forming apparatus that forms a color image by transferring toner images for respective colors formed on plural rotary photoreceptor drums onto a sheet through an intermediate transfer member, when a controller judges that magnification deviation is generated in a main-scanning direction in superposition of the toner images for respective colors, the controller forms a first color registration deviation detecting mark for detecting at least an amount of deviation in the main scanning direction on the intermediate transfer member, and when the controller judges that the magnification deviation is not generated in the main-scanning direction in the superposition of toner images for respective colors, the controller forms a second color registration deviation detecting mark for detecting only an amount of deviation in a sub scanning direction perpendicular to the main-scanning direction on the intermediate transfer member.

Abstract: Disclosed is an image forming apparatus, which makes it possible to appropriately conduct a controlling operation for eliminating the velocity fluctuation of the photoreceptor drum without generating any malfunction. The apparatus includes a photoreceptor member driven by a motor and a control section that is provided with a feed forward controlling section that stores parameters derived from driving errors for one revolution of the photoreceptor member to create a reverse-phase instruction value based on the parameters and a feedback controlling section that controls a velocity of the photoreceptor member, so as to keep the velocity of the photoreceptor member constant. During an initial operating time, the control section deactivates the feed forward controlling section, while only activates the feedback controlling section to drive the photoreceptor member so as to measure a driving toque of the driving motor, and selects a parameter from the parameters, corresponding to the driving toque measured.

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 an 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: 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: An image forming apparatus has a transfer attitude correcting section for correcting a transfer attitude of the transfer sheet to receive the toner image and for conveying the corrected transfer sheet to the transfer section with a timing to match with the movement of the toner image. The transfer attitude correcting section includes a roller unit including a base board rotatable around a center of rotation and a registration roller mounted on the base board, a detecting section for detecting a position of the transfer sheet being conveyed by the registration roller; and a control section for control the roller unit based on detection data detected by the detecting section so as to correct a skew of the transfer sheet by rotating the base board and to correct a deviation of a transfer position of the transfer sheet by shifting the registration roller on the base board.

Abstract: A color image forming apparatus for forming toner images by carrying out charging, exposure, and development on at least one photoreceptor drum, and forming color images by transferring the toner images onto sheets, the color image forming apparatus including: a photoreceptor drum which rotates around an axis; an exposure section which intermittently emits a light beam onto the cylindrical surface of the rotating photoreceptor drum along scanning lines parallel to the axis of the photoreceptor drum; a calculation section which calculates a printing ratio of a color image to be formed on one sheet, wherein the printing ratio is the ratio of the area covered by toner in the color image; and a timing control section which controls a timing when the exposure section emits the light beam in a direction of rotation of the photoreceptor drum based on the printing ratio calculated by the calculation section.

Abstract: An image forming apparatus having a color mode and a monochromatic mode, which includes: a transmission member, which can be switched between a transmitted state where a motor transfers a drive force to a single photoreceptor drum and a non-transmitted state where the motor does not transfer the drive force to the single photoreceptor drum; and a controller which switches to the non-transmitted state while executing an image formation in the monochromatic mode, and when a command to execute a next image formation is not instructed, switches to the transmitted state after a phase adjustment of each photoreceptor drum after the image formation in the monochromatic mode, and controls the motor to execute a slight rotation operation at every prescribed period of time by synchronizing plural drums including the single photoreceptor drum with each other through the transmission member.

Abstract: An image forming apparatus including photoconductor drums corresponding to colors, motors, gears to transmit each rotation of the motors to each of the photoconductor drums, each of two gears comprising a portion to be detected intermittently continuing in a circumferential direction at a position having same radius centering around a rotary shaft of the gears, a pair of phase sensors to output detection signals of signal logics according to an existence or a non-existence of the portion to be detected at a point symmetric position centering around the rotary shaft of each of two gears and a control unit to calculate a rotation phase difference between each of the gears based on a logical combination of the detection signals which are output from the pair of phase sensors and to control the motors so as to synchronize rotation of each of the gears based on the calculated rotation phase difference.

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: 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.