An image forming apparatus includes: a controller configured to: control first and second image forming units to form a plurality of groups of detection images, the plurality of groups of detection images being scaled based on a scaling factor, determine a plurality of detection start timings that respectively correspond to the plurality of groups based on the scaling factor, control a detection unit to detect the plurality of groups based on the determined detection start timings, and control the detected misregistration of a first image to be formed by the first image forming unit and a second image to be formed by the second image forming unit.

A scanning optical apparatus includes a light source, a deflector and an imaging optical system. The deflector deflects a beam emitted from the light source to scan a scanning surface with the beam in a main scanning direction. The imaging optical system focuses the beam on the scanning surface. The imaging optical system includes a first lens having negative power in a sub scanning direction and a second lens having positive power in the sub scanning direction, in which the sub scanning direction is parallel to the scanning surface and perpendicular to the main scanning direction. The power 1 of the first lens, the power 2 of the second lens and a magnification in the sub scanning direction of the imaging optical system satisfy the conditions 1.21/20.9 and 1.30.8.

An image forming apparatus including: a light source configured to emit a light beam based on an image signal; a deflector configured to deflect the light beam so that the light beam emitted from the light source is scanned on a surface of a photosensitive member in a main scanning direction; a storage portion configured to store a first magnification of an image with respect to a scanning position in the main scanning direction; and a controller configured to generate a second magnification of the image with respect to a reference color image, wherein the controller generates a third magnification based on the first magnification corrected based on the second magnification and the second magnification to correct the image signal based on the third magnification.

An image forming apparatus includes an exposure unit that reflects a laser beam emitted from a light source by a polygon mirror having a plurality of reflection surfaces to form a latent image on a photosensitive member, and a control unit that controls the image forming apparatus in a plurality of operation modes including a normal mode and a low speed mode having a slower process speed than the normal mode. The control unit controls the polygon mirror to use all of the plurality of reflection surfaces to reflect the laser beam when in the normal mode. When in the low speed mode, the control unit makes the process speed faster than 0.5 times that of the normal mode, rotates the polygon mirror faster than in the normal mode, and controls the polygon mirror to use only some of the plurality of reflection surfaces to reflect the laser beam.

A method of operating a printing system includes determining whether ghosting is expected on a photoreceptor and applying power to a laser applied to the photoreceptor based on whether the ghosting is expected.

A scanning optical apparatus includes a light source, a deflector and an imaging optical system. The deflector deflects a beam emitted from the light source to scan a scanning surface with the beam in a main scanning direction. The imaging optical system focuses the beam on the scanning surface. The imaging optical system includes a first lens having negative power in a sub scanning direction and a second lens having positive power in the sub scanning direction, in which the sub scanning direction is parallel to the scanning surface and perpendicular to the main scanning direction. The power 1 of the first lens, the power 2 of the second lens and a magnification in the sub scanning direction of the imaging optical system satisfy the conditions 1.21/20.9 and 1.30.8.

An image forming apparatus, including: a light source; a deflection device; a lens configured to image a light beam emitted from the light source based on an image signal and deflected by the deflection device on a surface of a photosensitive member; and a controller configured to execute partial magnification correction for correcting a partial magnification as a deviation amount of a scanning speed of the light beam at a position different from a reference position in a main scanning direction with respect to a scanning speed at the reference position, wherein the controller is configured to: execute, when an image type of the image is a line image, the partial magnification correction on the image signal at a resolution less than one pixel; and execute, when the image type is a graphic image, the partial magnification correction on the image signal at a resolution in unit of one pixel.

A light source includes a light emitting element, and an optical system that directs light output from the light emitting element to a surface of a photosensitive member. An irradiation amount of light for forming a second electrostatic latent image is larger than an irradiation amount of light for forming a first electrostatic latent image. A position at which a propagation efficiency of light peaks in a scanning direction of the light is located between a center of an image height of the optical system and a surface area in which the second electrostatic latent image is formed out of the surface of the photosensitive member.

An image forming apparatus includes a photosensitive member; an exposure portion configured to expose the photosensitive member to light depending on image information to form a latent image on the photosensitive member; a developing portion configured to develop the latent image into a toner image with toner; and a transfer portion configured to transfer the toner image from the photosensitive member onto a recording material. The image forming apparatus changes a surface movement speed of the photosensitive member at timing prior to predetermined timing, when a moving speed of a recording material at the transfer portion changes, by a predetermined time.

In an image forming apparatus, a correction control unit of an image clock control unit controls the frequency of an image clock, so that the partial magnification of each position in an image region in which an image is formed is corrected in a main scanning direction that is a direction in which a laser beam scans a scanning region of one line. When controlling the frequency of the image clock, the correction control unit makes the change rate (the slope) that is a change amount of the image clock per unit time, be smaller in a non-image region being a region other than the image region, than the change rate in the image region.