In an image forming apparatus that employs a laser scanning optical system that does not use an fθ lens, in the case where magnification correction by insertion/removal of an auxiliary pixel is performed based on the premise of digital PWM, an insertion/removal position of an auxiliary pixel is controlled in accordance with a purpose of each piece of image processing.

A light source adjustment apparatus is disclosed. The light source adjustment apparatus includes processing apparatus to receive a scanned image of a pattern printed by a print apparatus onto a printable medium, the pattern including a plurality of blocks of print agent of a first colour printed during a printing operation in which light sources of a light source array irradiate a photoconductive surface; analyse the scanned image to identify a region of non-uniformity within the plurality of blocks of print agent; correlate a location of the identified region of non-uniformity with a corresponding light source in the light source array; determine, based on the identified region of non-uniformity, an adjustment to be made to a parameter of the corresponding light source; and generate a signal to effect the determined parameter adjustment with regard to the corresponding light source. A method and a print apparatus are also disclosed.

An optical writing device and an image forming apparatus incorporating the optical writing device. The optical writing device includes two or more light sources, a pixel clock generator to measure a scanning speed of one of the two or more light sources and generate a pixel clock of a cycle corrected according to the measured scanning speed, a pulse data generation and output unit to generate pulse width data and shift data for the pixel clock generated by the pixel clock generator to output the generated pulse width data and the generated shift data for each one of the two or more light sources, and a plurality of image pulse generation and output units to generate an image pulse. In the optical writing device, the plurality of image pulse generation and output units are supplied with the pixel clock in common.

A method for reducing image burn-in artifacts in an electrophotographic printing system, includes receiving a print job including image data for a set of pages to be printed. The pages are analyzed to determine that the image data for a sequence of pages in the print job are similar. The similar pages are printed using a pattern of lateral translations wherein the image data is laterally translated such that it is printed at a different lateral position on the printed page.

A semiconductor laser driver and an image forming apparatus incorporating the semiconductor laser driver. The semiconductor laser driver includes a light source including a plurality of laser-beam source units disposed in a sub-scanning direction that serves as a group direction, the laser-beam source units having a plurality of groups arranged in a main scanning direction, each of the laser-beam source units emitting a laser beam of a light quantity dependent upon a driving current, a shading corrector to correct, according to at least one shading correction value, the driving current given to the laser-beam source units for each of the groups, and a light quantity adjuster to adjust the driving current according to a light-quantity adjustment value for the laser-beam source units. The image forming apparatus includes a semiconductor laser drive circuit, and the semiconductor laser driver that serves as the semiconductor laser driver.

An image forming apparatus, including: a light source including a plurality of light emitting points and configured to emit light beams; a photosensitive member configured to rotate in a rotation direction so that a latent image is formed thereon with the light beams; a rotary polygon mirror configured to rotate around a rotation axis and having a plurality of mirror faces each configured to deflect the light beams so that the photosensitive member is scanned with the light beams; a detector configured to detect temperature; and a correction unit configured to correct image data of an input image by using a deviation amount, in the rotation direction of the photosensitive member, of the light beams deflected by each of the plurality of mirror faces, wherein the correction unit obtains the deviation amount according to the temperature detected by the detector.

Separately providing a shift register for performing serial-to-parallel conversion on a BD signal and a shift register for performing parallel-to-serial conversion on a bit pattern to generate a PWM signal increases the scale of a circuit for adjusting a writing start position in the scanning direction of a light beam. Therefore, the shift register for performing serial-to-parallel conversion on a BD signal and the shift register for performing parallel-to-serial conversion on a bit pattern to generate a PWM signal are configured as a common register.

An image forming apparatus includes: a scanning unit configured to form an electrostatic latent image on a photoconductor by scanning the photoconductor with one or more scanning beams in a main scanning direction based on an image signal, repetitively in a sub-scanning direction perpendicular to the main scanning direction; a generating unit configured to perform halftone processing on image data to generate the image signal; and a storage unit configured to store correction information. The correction information is set such that start positions of a plurality of scanning lines are linearly displaced to either a negative side or a positive side of the main scanning direction along the sub-scanning direction, in accordance with a direction of a first vector forming a smaller angle with the sub-scanning direction among two vectors in the halftone processing.

A light emitting device includes a light-emitting element row that includes light emitting elements arranged in a row in a main scanning direction, an optical element that is used for forming an electrostatic latent image by focusing light outputs of the light emitting elements and exposing a photoconductor to light and a control unit that controls light emission of the light-emitting element row. The light-emitting element row is divided into groups, and the control unit uniformly corrects a light intensity of each of the light emitting elements included in the groups on a group-by-group basis by a first correction method so as to correct density unevenness in the main scanning direction.

A method for reducing image burn-in artifacts in an electrophotographic printing system, includes receiving a print job including image data for a set of pages to be printed. The pages are analyzed to determine that the image data for a sequence of pages in the print job are similar. The similar pages are printed using a pattern of lateral translations wherein the image data is laterally translated such that it is printed at a different lateral position on the printed page. The similar pages can also be printed using a pattern of page orientations including a first page orientation and a second page orientation, wherein the image data for the second page orientation is rotated 180 degrees relative to the image data for the first page orientation.