Abstract: An exposure head includes a light emitting board group, a first lens array, and a second lens array. The light emitting board group disposes a plurality of light emitting boards each including a plurality of light emitting elements disposed side by side in a second direction intersecting with the first direction. The plurality of light emitting boards are disposed along the second direction and alternately in the first direction. The light emitting board group includes a first light emitting board group and a second light emitting board group. The first lens array condenses light emitted from the plurality of light emitting elements disposed on the first light emitting board group onto the surface of the image bearing member. The second lens array condenses light emitted from the plurality of light emitting elements disposed on the second light emitting board group onto the surface of the image b earing member.

Abstract: An image forming apparatus includes a main assembly and a drawer unit. The drawer unit includes a photosensitive drum, an optical print head, first to third wall portions and a relay substrate. The main assembly includes a first facing portion, a second facing portion and a main assembly substrate. The relay substrate and the main assembly substrate are connected by a cable folded back at the rear of the third wall portion. A distance between a portion of the cable before being folded back and a portion of the cable after being folded back is longer than a distance, with respect to a longitudinal direction of the optical print head, between the first or second wall portion on which the relay substrate is provided and the first or second facing portion facing the first or second wall portion on which the relay substrate is provided.

Abstract: An image forming apparatus includes a main assembly and a drawer unit. The drawer unit includes a photosensitive drum, an optical print head, first to third wall portions and a relay substrate. The main assembly includes a first facing portion, a second facing portion and a main assembly substrate. The relay substrate and the main assembly substrate are connected by a cable folded back at the rear of the third wall portion. A distance between a portion of the cable before being folded back and a portion of said cable after being folded back is larger than a distance, with respect to a longitudinal direction of the optical print head, between the first or second wall portion on which the relay substrate is provided and the first or second facing portion facing the first or second wall portion on which the relay substrate is provided.

Abstract: A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.

Abstract: A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.

Abstract: An image forming apparatus capable of correcting relative position in exposure position between laser beams that scan a photosensitive drum in a scanning direction of the laser beams. A semiconductor laser includes first and second light emitting elements for emitting first and second laser beams. These elements are arranged such that the laser beams expose positions on the photosensitive drum different in the sub scanning direction. A polygon mirror deflects the laser beams to scan the photosensitive drum. Relative position in the scanning direction between images to be formed on the photosensitive drum by exposure by the first and second laser beams is corrected based on correction data. An image data generation section generates drive signals associated with the respective light emitting elements. A semiconductor laser drive circuit causes the semiconductor laser to emit the first and second laser beams, based on the drive signals.

Abstract: An image forming apparatus is provided for controlling current(s) supplied to a semiconductor laser. In one or more embodiments, an image forming apparatus corrects a value of the driving current and a value of at least one correction current (e.g., first and/or second correction current(s)) supplied in synchronization with the supply start of the driving current based on a reception result of a light receiving unit. In one or more embodiments, an image forming apparatus includes a correction current supply unit including a first correction current generation unit for generating a first correction current that attenuates over time and a second correction current generation unit for generating a second correction current that attenuates over time and of which an attenuation speed is lower than that of the first correction current, and configured to supply the first correction current and the second correction current to the semiconductor laser.

Abstract: In an optical scanning apparatus, a light source includes a plurality of light emitting elements. A light beam output from the source is scanned and deflected by a polygon mirror so as to form an electrostatic latent image on a surface of a light sensitive member. A control unit controls the source so that the source outputs the light beam in a first period before a second period in which the light beam deflected by the mirror forms the image. During the first period for outputting the light beam from the source a period for scanning a non-image region of the member in a state in which the rotation speed of the mirror is being accelerated or decelerated is made longer than a period for scanning the non-image region of the member in a state in which the rotation speed of the mirror is controlled at a constant speed.

Abstract: An image forming apparatus according to an aspect of the present invention uses a BD sensor to measure a time interval between light beams emitted from two light emitting elements in a period during which constant speed control for maintaining the rotation speed of a polygon mirror at a target speed is performed and speed change control for accelerating or decelerating the rotation speed toward the target speed is not performed. Based on the time interval between BD signals generated according to the two light beams that are incident on the BD sensor while the constant speed control is being executed, the image forming apparatus controls the emission timings of the light beams that are based on the image data for the light emitting elements.

Abstract: An image forming apparatus corrects a value of the driving current and a value of a correction current supplied in synchronization with the supply start of the driving current based on a reception result of a light receiving unit.

Abstract: A light source control apparatus that do not always require calculations for the upper limit of driving current when characteristic of a light source varies. The light source control apparatus controls a light source that exhibits a characteristic including an uptrend region where the light amount increases with increasing driving current and a downtrend region where the light amount decreases with increasing driving current. A determination unit determines whether the light source is in the uptrend or downtrend region based on signals from a light variation detection unit and a current variation detection unit. A control unit matches the light amount (L) with target light amount (T), by increasing the driving current when L<T in the uptrend region or when L>T in the downtrend region, and by decreasing the driving current when L>T in the uptrend region and when L<T in the downtrend region.

Abstract: An image forming apparatus capable of correcting relative position in exposure position between laser beams that scan a photosensitive drum in a scanning direction of the laser beams. A semiconductor laser includes first and second light emitting elements for emitting first and second laser beams. These elements are arranged such that the laser beams expose positions on the photosensitive drum different in the sub scanning direction. A polygon mirror deflects the laser beams to scan the photosensitive drum. Relative position in the scanning direction between images to be formed on the photosensitive drum by exposure by the first and second laser beams is corrected based on correction data. An image data generation section generates drive signals associated with the respective light emitting elements. A semiconductor laser drive circuit causes the semiconductor laser to emit the first and second laser beams, based on the drive signals.

Abstract: A frequency adjusting unit adjusts a frequency of the clock signal to be supplied to a drive unit when an image is to be formed on the second face in response to a contraction ratio of the printing material on which an image has been formed on the first face. The phase difference determining unit determines a phase difference between the clock signal corresponding to the first face and the clock signal corresponding to the second face in response to a frequency difference and a sign thereof between the clock signal corresponding to the first face and the clock signal corresponding to the second face. The change control unit changes from the clock signal corresponding to the first face to the clock signal corresponding to the second face.

Abstract: A frequency adjusting unit adjusts a frequency of the clock signal to be supplied to a drive unit when an image is to be formed on the second face in response to a contraction ratio of the printing material on which an image has been formed on the first face. The phase difference determining unit determines a phase difference between the clock signal corresponding to the first face and the clock signal corresponding to the second face in response to a frequency difference and a sign thereof between the clock signal corresponding to the first face and the clock signal corresponding to the second face. The change control unit changes from the clock signal corresponding to the first face to the clock signal corresponding to the second face.

Abstract: A frequency adjusting unit adjusts a frequency of the clock signal to be supplied to a drive unit when an image is to be formed on the second face in response to a contraction ratio of the printing material on which an image has been formed on the first face. The phase difference determining unit determines a phase difference between the clock signal corresponding to the first face and the clock signal corresponding to the second face in response to a frequency difference and a sign thereof between the clock signal corresponding to the first face and the clock signal corresponding to the second face. The change control unit changes from the clock signal corresponding to the first face to the clock signal corresponding to the second face.

Abstract: In an optical scanning apparatus, a light source includes a plurality of light emitting elements. A light beam output from the source is scanned and deflected by a polygon mirror so as to form an electrostatic latent image on a surface of a light sensitive member. A control unit controls the source so that the source outputs the light beam in a first period before a second period in which the light beam deflected by the mirror forms the image. During the first period for outputting the light beam from the source a period for scanning a non-image region of the member in a state in which the rotation speed of the mirror is being accelerated or decelerated is made longer than a period for scanning the non-image region of the member in a state in which the rotation speed of the mirror is controlled at a constant speed.

Abstract: A frequency adjusting unit adjusts a frequency of the clock signal to be supplied to a drive unit when an image is to be formed on the second face in response to a contraction ratio of the printing material on which an image has been formed on the first face. The phase difference determining unit determines a phase difference between the clock signal corresponding to the first face and the clock signal corresponding to the second face in response to a frequency difference and a sign thereof between the clock signal corresponding to the first face and the clock signal corresponding to the second face. The change control unit changes from the clock signal corresponding to the first face to the clock signal corresponding to the second face.

Abstract: Image forming apparatus in which surface electric potentials of a plurality of surface areas are detected by charging a photoconductor with a different applied bias for each predetermined timing and exposing a plurality of surface areas of the photoconductor by scanning the photoconductor with an optical beam, while changing an exposure intensity of the optical beam for each of the surface areas of the photoconductor. Then, the applied bias necessary for obtaining a predetermined electric potential of a dark section and the exposure intensity of the optical beam necessary for obtaining a predetermined electric potential of a bright section are controlled, on the basis of the surface electric potentials that are detected respectively from the different applied biases and the different exposure intensities. Thereby, the adjustment time can be made shorter than the conventional case.

Abstract: An image forming apparatus including an adjustment unit adapted to adjust an image to be formed by an image forming unit advises the next adjustment execution timing on the basis of cumulative use information obtained by the image forming unit, and changes the advised adjustment timing on the basis of selection input.

Abstract: Image forming apparatus in which surface electric potentials of a plurality of surface areas are detected by charging a photoconductor with a different applied bias for each predetermined timing and exposing a plurality of surface areas of the photoconductor by scanning the photoconductor with an optical beam, while changing an exposure intensity of the optical beam for each of the surface areas of the photoconductor. Then, the applied bias necessary for obtaining a predetermined electric potential of a dark section and the exposure intensity of the optical beam necessary for obtaining a predetermined electric potential of a bright section are controlled, on the basis of the surface electric potentials that are detected respectively from the different applied biases and the different exposure intensities. Thereby, the adjustment time can be made shorter than the conventional case.