Abstract: A luminance nonuniformity adjustment module for eliminating luminance nonuniformities in light emitting elements determines a luminance correction coefficient for each light-emitting element through a test print. The luminance nonuniformity adjustment module comprises a provisional luminance correction coefficient calculation unit, an improper coloring degree calculation unit and a luminance correction coefficient determination unit. The provisional luminance correction coefficient calculation unit calculates a provisional luminance correction coefficient by comparing a measured density value for a grayscale chart and a predetermined target density value. The improper coloring degree calculation unit calculates an improper coloring degree, which is the degree of improper coloring that occurs when other colors are expressed when developing a specific color, from the measured density values for the grayscale chart and an unbalanced chart in which the gray balance has been altered.

Abstract: A printing apparatus for measuring proper density and generating correction data with high accuracy by eliminating influences of adjoining areas. A plurality of scanning coordinates SAx are set to a middle position in a primary scanning direction of each of pixel lines Q on a test chart. Scanning areas SA are set to positions where the scanning coordinates SAx intersect scanning coordinates SAy indicating numerous positions in a secondary scanning direction of the pixel lines Q. Density data of the scanning areas SA is averaged to generate correction data for updating a correction table.

Abstract: A printing apparatus for generating a test chart using a plurality of sheets of printing paper and correction data having high accuracy according to the test chart. Overlapping regions G are extracted from scanning data D1 and D2 of two test charts. Tendency in variation (inclination) of the density is obtained for one set of the scanning data in the overlapping regions G and such tendency in variation is reduced. The scanning data D1 and D2 are then combined together to eliminate the density difference, thereby obtaining a single set of combined scanning data D3. A correction data generation means updates a correction table based on density data of the scanning data D3.

Abstract: A method of gradation correction for laser scanning exposure is effected, based on measured density values of a test print (TP) including a horizontal stripe test pattern comprised of a plurality of horizontal lines extending in the main scanning direction and a vertical stripe pattern comprised of a plurality of vertical lines extending in the sub scanning direction. The includes the steps of calculating, based on the measured density values, a rising correction amount for main scanning rising correction of adding a rising correction component to one dot after rising of a modulated laser in order to reduce density difference between the horizontal line and the vertical line and calculating, based on the measured density values, a falling correction amount for main scanning falling correction of adding a falling correction component to one dot after rising of the modulated laser in order to reduce the density difference between the horizontal line and the vertical line.

Abstract: A color image printer includes a print engine (13) for effecting a laser scanning exposure and a test print managing section (51) for managing control for outputting a test print through the print engine for use in image quality adjustment. The test print (TP) includes a plurality of sets of horizontal stripe test patterns having a plurality of horizontal lines extending in the main scanning direction and a plurality of sets of vertical stripe test patterns having a plurality of vertical lines extending in the sub scanning direction. The horizontal stripe test patterns and the vertical stripe test patterns are arranged in alternation. And, the horizontal lines are formed with a gradation value set in advance for each horizontal stripe test pattern. The vertical lines are formed with a gradation value set in advance for each vertical stripe test pattern.

Abstract: A color chart and a grayscale chart are output, and a calibration task of calculating a correction amount based on the grayscale chart by comparing a measured density value that is obtained by measuring a density of the grayscale chart and a target density value that has been found in advance, is repeated until the correction amount based on the grayscale chart is equal to or less than a first tolerance value, and at this time, as long as the correction amount based on the grayscale chart is equal to or greater than a second tolerance value that is larger than the first tolerance value, a correction amount based on the color chart is additionally calculated by comparing a measured density value that is obtained by measuring a density of the color chart and a target density value that has been found in advance, and this correction amount is used in place of the correction amount based on the grayscale chart.

Abstract: An exposure apparatus of the invention has a dot array head of a fluorescent type having light-emitting units UR, UG, UB of three primary colors. A controller E is provided with an area dividing unit that divides the dot array head into an image area, in which control of light emission based on image data is performed, and the other non-image areas. In addition, a dot array head control unit in the controller E comprises a light emission control unit that controls the dot array head such that light is emitted based on the image data in the image area and dummy light emission takes place in the non-image area when exposing photographic paper. The dummy light emission data is created by the dummy light emission data creating unit, based on image data corresponding to a single dot D1 adjacent to a boundary of the image area and the non-image area.

Abstract: A luminance nonuniformity adjustment module for eliminating luminance nonuniformities in light emitting elements determines a luminance correction coefficient for each light-emitting element through a test print. The luminance nonuniformity adjustment module comprises a provisional luminance correction coefficient calculation unit, an improper coloring degree calculation unit and a luminance correction coefficient determination unit. The provisional luminance correction coefficient calculation unit calculates a provisional luminance correction coefficient by comparing a measured density value for a grayscale chart and a predetermined target density value. The improper coloring degree calculation unit calculates an improper coloring degree, which is the degree of improper coloring that occurs when other colors are expressed when developing a specific color, from the measured density values for the grayscale chart and an unbalanced chart in which the gray balance has been altered.

Abstract: A printing apparatus for generating a test chart using a plurality of sheets of printing paper and correction data having high accuracy according to the test chart. Overlapping regions G are extracted from scanning data D1 and D2 of two test charts. Tendency in variation (inclination) of the density is obtained for one set of the scanning data in the overlapping regions G and such tendency in variation is reduced. The scanning data D1 and D2 are then combined together to eliminate the density difference, thereby obtaining a single set of combined scanning data D3. A correction data generation means updates a correction table based on density data of the scanning data D3.

Abstract: A printing apparatus for measuring proper density and generating correction data with high accuracy by eliminating influences of adjoining areas. A plurality of scanning coordinates SAx are set to a middle position in a primary scanning direction of each of pixel lines Q on a test chart. Scanning areas SA are set to positions where the scanning coordinates SAx intersect scanning coordinates SAy indicating numerous positions in a secondary scanning direction of the pixel lines Q. Density data of the scanning areas SA is averaged to generate correction data for updating a correction table.

Abstract: A color chart and a grayscale chart are output, and a calibration task of calculating a correction amount based on the grayscale chart by comparing a measured density value that is obtained by measuring a density of the grayscale chart and a target density value that has been found in advance, is repeated until the correction amount based on the grayscale chart is equal to or less than a first tolerance value, and at this time, as long as the correction amount based on the grayscale chart is equal to or greater than a second tolerance value that is larger than the first tolerance value, a correction amount based on the color chart is additionally calculated by comparing a measured density value that is obtained by measuring a density of the color chart and a target density value that has been found in advance, and this correction amount is used in place of the correction amount based on the grayscale chart.

Abstract: A pneumatic tire pressure determining system on a motor vehicle detects an actual rotational speed difference between rotational speeds of front or rear left and right road wheels of the motor vehicle, detects an operating condition of the motor vehicle, and calculates an adequate rotational speed difference between rotational speeds of the front or rear left and right road wheels based on the detected operating condition of the motor vehicle. The system compares the adequate rotational speed difference and the actual rotational speed difference, and when the difference between the compared actual and adequate rotational speed differences exceeds a predetermined value, the system determines a pneumatic tire pressure reduction.