An image forming apparatus includes a light scanning device, a developing portion, a control portion and a storage portion. The storage portion stores an evaluation chart. The evaluation chart includes a first evaluation pattern and a second evaluation pattern. The first evaluation pattern includes a first patch row. The first patch row is formed by arranging a plurality of first evaluation patches. The first evaluation patch includes a first dot row, a second dot row and an auxiliary dot row. The second evaluation pattern includes a second patch row. The second patch row is formed by arranging a plurality of second evaluation patches.

An image forming apparatus includes a light scanning device, a developing portion, a control portion and a storage portion. The storage portion stores an evaluation chart. The evaluation chart includes a first evaluation pattern and a second evaluation pattern. The first evaluation pattern includes a first patch row. The first patch row is formed by arranging a plurality of first evaluation patches. The first evaluation patch includes a first dot row, a second dot row and an auxiliary dot row. The second evaluation pattern includes a second patch row. The second patch row is formed by arranging a plurality of second evaluation patches.

A plurality of light sources, an optical deflector including a rotational member configured to be rotational about an axis of rotation thereof, and a plurality of reflective members, are provided in a light scanning unit for an image forming apparatus. The optical deflector is arranged to deflect light incident obliquely from the plurality of light sources and the plurality of reflective members are arranged to reflect the light deflected by the optical deflector to a plurality of surfaces, which are to be scanned and correspond to the plurality of light sources, and arranged such that scan lines on opposite surfaces with respect to the axis of rotation of the optical deflector among the plurality of surfaces to be scanned are bent in the same direction.

A plurality of light sources, an optical deflector including a rotational member configured to be rotational about an axis of rotation thereof, and a plurality of reflective members, are provided in a light scanning unit for an image forming apparatus. The optical deflector is arranged to deflect light incident obliquely from the plurality of light sources and the plurality of reflective members are arranged to reflect the light deflected by the optical deflector to a plurality of surfaces, which are to be scanned and correspond to the plurality of light sources, and arranged such that scan lines on opposite surfaces with respect to the axis of rotation of the optical deflector among the plurality of surfaces to be scanned are bent in the same direction.

A print engine includes a printer module for printing image data in a plurality of different print modes, wherein each print mode has an associated line print time. A data interface receives image data and associated metadata for a print job from a pre-processing system, the metadata including print mode metadata. A digital memory stores a plurality of pulse timing functions, each pulse timing function corresponding to one of the line print times associated with the plurality of print modes. A metadata interpreter interprets the metadata and determines the print mode to be used to print the image data. A printer module controller controls the printer module to print the image data using the pulse timing function corresponding to the line print time associated with the print mode, wherein each light source is activated for a pulse count corresponding to a pixel code value of an associated image pixel.

A print engine includes a printer module for printing image data in a plurality of different print modes, wherein each print mode has an associated line print time. A data interface receives image data and associated metadata for a print job from a pre-processing system, the metadata including print mode metadata. A digital memory stores a plurality of pulse timing functions, each pulse timing function corresponding to one of the line print times associated with the plurality of print modes. A metadata interpreter interprets the metadata and determines the print mode to be used to print the image data. A printer module controller controls the printer module to print the image data using the pulse timing function corresponding to the line print time associated with the print mode, wherein each light source is activated for a pulse count corresponding to a pixel code value of an associated image pixel.

An image forming apparatus, based on print target image data, obtains a video count of a developer unit that forms an image on a photoconductor for each of regions divided in a scanning direction of a laser that exposes the photoconductor. Also after obtaining the video count, halftone processing is performed on the image data. Based on the obtained video count, patch data for cleaning the photoconductor corresponding to each region is generated. The developer unit is controlled to execute image formation based on image data for which the halftone processing is performed, and to execute image formation based on the generated patch data.

An image forming apparatus of the present invention acquires first correction characteristics representing an output density for an input gradation value at a reference position in a main scanning direction and second correction characteristics representing a relative relationship of an output density at a predetermined position in the main scanning direction with the output density at the reference position in the main scanning direction. Then, the image forming apparatus corrects image data corresponding to the predetermined position in the main scanning direction based on the first correction characteristics and the second correction characteristics.

In an image forming apparatus that employs a laser scanning optical system that does not use an f 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 print engine includes a printer module for printing image data in a plurality of different print modes, wherein each print mode has an associated line print time. A data interface receives image data and associated metadata for a print job from a pre-processing system, the metadata including print mode metadata. A digital memory stores a plurality of pulse timing functions, each pulse timing function corresponding to one of the line print times associated with the plurality of print modes. A metadata interpreter interprets the metadata and determines the print mode to be used to print the image data. A printer module controller controls the printer module to print the image data using the pulse timing function corresponding to the line print time associated with the print mode, wherein each light source is activated for a pulse count corresponding to a pixel code value of an associated image pixel.