An exposure apparatus includes light-emitting elements arranged along a direction of a rotation axis of a photosensitive member and at least one processor. The at least one processor is configured to controls driving of the light-emitting elements, generate correction data for use in increasing or decreasing the number of the light-emitting elements to be turned on based on a correction amount for correcting unevenness in light amount, and correct image data in accordance with a value indicated by the correction data. For a pixel for which the correction amount indicates a value exceeding a predetermined limit value, the correction data indicates a value that is equal to or smaller than the limit value.

An image processing method is for generating print data to cause a printing apparatus that prints a print image based on image data to execute printing, by repeating a pass operation in which a nozzle set forms dots on a printing medium while moving in a main scanning direction, and a feed operation in which the nozzle set and the printing medium are moved in a sub-scanning direction. The image processing method includes: performing a first and second halftone processes for a same region of the image data to respectively generate a first halftone data to determine a formation state of first dots and a second halftone data to determine a formation state of second dots, the first and second dots being formed by the nozzle set that ejects a same color of ink; and allocating the first halftone data and the second halftone data to pass operations.

Under-color removal of show-through background from a scanned original, so as to retain chromatic highlights of the scanned image of the original. An under-color level defines a value at which signals having a higher luminance than a luminance of the under-color level are converted into white. Before under-color removal, and based on the scanned image of the original, an achromatic color is converted into a color closer to white than the under-color level for an achromatic color closer whose luminance falls in a specified range lower than the luminance of the under-color level; and a chromatic color is converted into a chromatic color having a lower luminance than the luminance of the under-color level for a chromatic color in the specified range. Under-color removal of the converted achromatic and chromatic colors is thereafter applied using the under-color level, by which signal values having a higher luminance than a luminance of the under-color level are converted into white.

An image forming apparatus includes a forming unit, a storage unit, a correction unit, a measurement unit, and a changing unit. The forming unit forms an image. The storage unit stores correction data for correcting density irregularity in each of a plurality of regions obtained through division in a main scanning direction of the image formed by the forming unit. The correction unit corrects a density of the image formed by the forming unit for each of the plurality of regions based on the correction data stored in the storage unit. The measurement unit measures an image formation density by the forming unit in association with the correction by the correction unit. The changing unit changes the image formation density by the forming unit with a uniform change amount in the plurality of regions so that the image formation density measured by the measurement unit approaches a predetermined target density.

A printing system includes a machine readable storage medium storing instructions and a processor to execute the instructions. The processor is to execute the instructions to receive a source image comprising a plurality of regions and analyze each region of the plurality of regions to determine an ink density of each region. The processor is to execute the instructions to further in response to the ink density for a region exceeding a threshold, deplete the ink density for the region; and in response to the ink density for a region not exceeding the threshold, maintain the ink density for the region. The processor is to execute the instructions to further combine the depleted regions and the maintained regions to generate an optimized image.

An image processing apparatus includes a data input unit, an operation panel, a storage unit, and a control unit. The operation panel accepts a registration of a margin image and a setting of an emphasis region within the margin image. The storage unit stores data for emphasis including a registered margin image and positional data. The registered margin image is the margin image that has been registered, and the positional data indicates a position of the emphasis region in the registered margin image. When the control unit determines that the registered margin image is included in the page image data, the control unit performs an emphasis process on an image of a corresponding region whose position at the registered margin image included in the page image data is identical to a position of the emphasis region in the registered margin image included in the stored data for emphasis.

An image processing apparatus sets a threshold value matrix for each of multiple color materials, and uses the set threshold value matrix to acquire a first threshold value. On the other hand, the image processing apparatus sets reference data on the basis of multivalued data of that color material. Then, the image processing apparatus calculates a second threshold value matrix by performing a predetermined process on the first threshold value on the basis of the reference data for that color material. Further, by comparing the second threshold value with the multivalued data, quantization data for printing a dot is generated. When doing this, the threshold value matrix and the reference data for that color material are set so as to make the graininess of a dot pattern of that color material lower than the graininess of a mixed color dot pattern obtained by mixing dot patterns of the respective multiple color materials.

An image processing device includes circuitry to segment an image corresponding to input image data into a black text area including black text and a non-black text area of the image data other than the black text area, perform a first type of color correction on pixel data items in the black text area and a second type of color correction on pixel data items in the non-black text area to generate a processed image, and determine whether or not the image is a color image using the processed image. The second type of color correction is different from the first type of color correction.

An image forming system includes: an image forming unit configured to form an image on a sheet. The image forming unit forms a first image inside a trimming region of a sheet, and forms a second image and an adjustment pattern outside the trimming region of the sheet, the adjustment pattern being for adjusting an image forming condition. Execution of instructions causes one or more processors to adjust the image forming condition at a time of image formation by the image forming unit, and, in a case where a formation region of the second image and at least a part of a formation region of the adjustment pattern overlap, control a display to display information indicating that the formation region of the second image and the formation region of the adjustment pattern overlap.

A liquid discharge apparatus includes a conveyor, a liquid discharge unit, a reader, and circuitry. The conveyor conveys a recording medium in a conveyance direction. The liquid discharge unit forms an image on the recording medium. The reader reads the image. The circuitry causes the liquid discharge unit to form a mark image on the recording medium, causes the reader to read the mark image to obtain read information, corrects an image to be formed based on the read information, and causes the liquid discharge unit to form the image, corrected based on the read information, on the recording medium. The mark image includes a first mark image including two or more vertical lines extending in the conveyance direction and two or more horizontal lines extending in a width direction. Each of the two or more vertical lines intersects or contacts each of the two or more horizontal lines.