An image processing unit includes a region separation device and a spatial filtering device. The region separation device detects line widths of a manuscript image in which the line widths are different between a vertical line and a horizontal line and determines which of the vertical line or the horizontal line is thinner. The spatial filtering device executes an emphasizing process to make a widening ratio of a thinner line of the vertical line or the horizontal line higher than a widening ratio of the other line.

In accordance with an embodiment, an image forming apparatus comprises a deflector, a photoconductor, a mirror, a displacement mechanism and a control section. The deflector deflects laser light emitted from a light source to an optical path of each color in a horizontal scanning direction. The photoconductor is located in each optical path and forms an image of each color through development of an electrostatic latent image formed by being exposed by the laser light. The mirror is located in each optical path and reflects the laser light to each corresponding photoconductor. The displacement mechanism is arranged on each mirror and displaces the mirror in order to correct an inclination shift between images of respective colors. The control section corrects a magnification of the image of each color in the horizontal scanning direction according to an inclination correction amount of the image of each color.

Disclosed are methods and systems for compensating for process direction banding associated with a document processing system including a ROS. According to one exemplary embodiment, a ROS driver uses a plurality of beam delay/advance values to compensate for banding caused by an interaction of a halftone pattern and process direction density variations associated with the ROS.

Disclosed are methods and systems for compensating for process direction banding associated with a document processing system including a ROS. According to one exemplary embodiment, a ROS driver uses a plurality of beam delay/advance values to compensate for banding caused by an interaction of a halftone pattern and process direction density variations associated with the ROS.

An image forming apparatus includes a reading unit for sequentially reading, from image data, pieces of pixel data of target pixels along a predetermined direction, a cumulative sum calculation unit for calculating a cumulative sum of gradation values represented by pieces of pixel data of target pixels in a significant image portion read by the reading unit, a determination unit for determining whether the target pixel read by the reading unit is located at a boundary between the significant image portion and a background portion that is a non-significant image portion, and a correction unit for correcting, if the determination unit determines that the target pixel is located at the boundary, a gradation value represented by pixel data of the target pixel by adding a correction amount based on the cumulative sum up to the target pixel calculated by the cumulative sum calculation unit to the gradation value.

An image forming apparatus includes a reading unit for sequentially reading, from image data, pieces of pixel data of target pixels along a predetermined direction, a cumulative sum calculation unit for calculating a cumulative sum of gradation values represented by pieces of pixel data of target pixels in a significant image portion read by the reading unit, a determination unit for determining whether the target pixel read by the reading unit is located at a boundary between the significant image portion and a background portion that is a non-significant image portion, and a correction unit for correcting, if the determination unit determines that the target pixel is located at the boundary, a gradation value represented by pixel data of the target pixel by adding a correction amount based on the cumulative sum up to the target pixel calculated by the cumulative sum calculation unit to the gradation value.

An image processing device includes a dithering circuit, a gradation correction pattern generating circuit, and a gradation correction pattern correcting circuit. The dithering circuit performs a dithering process on image data to generate dithered image data. The gradation correction pattern generating circuit sets, in multi-valued data, gradation information of each of pixels of the generated dithered image data, and generates a gradation correction pattern imitating the dithered image data. The gradation correction pattern correcting circuit performs pattern matching on the generated gradation correction pattern, and corrects the generated gradation correction pattern in accordance with a result of the pattern matching.

An image processing device includes a dithering circuit, a gradation correction pattern generating circuit, and a gradation correction pattern correcting circuit. The dithering circuit performs a dithering process on image data to generate dithered image data. The gradation correction pattern generating circuit sets, in multi-valued data, gradation information of each of pixels of the generated dithered image data, and generates a gradation correction pattern imitating the dithered image data. The gradation correction pattern correcting circuit performs pattern matching on the generated gradation correction pattern, and corrects the generated gradation correction pattern in accordance with a result of the pattern matching.

An optical scanning apparatus includes a light source, a deflector configured to deflect a light flux from this light source to scan a surface to be scanned in a main-scanning direction, an incident optical system configured to guide the light flux from the light source to a deflection surface of the deflector, and an imaging optical system configured to guide the light flux deflected by the deflector to the surface to be scanned. The optical scanning apparatus satisfies the following conditions: 0.5<|si|<2.2, 3.0<|so|<10.0, and 0.2<Li/Lo<0.4.

An optical scanning apparatus includes a light source, a deflector configured to deflect a light flux from this light source to scan a surface to be scanned in a main-scanning direction, an incident optical system configured to guide the light flux from the light source to a deflection surface of the deflector, and an imaging optical system configured to guide the light flux deflected by the deflector to the surface to be scanned. The optical scanning apparatus satisfies the following conditions: 0.5<|si|<2.2, 3.0<|so|<10.0, and 0.2<Li/Lo<0.4.