Abstract: A liquid crystal driving device includes: a power supply unit for monitoring, using a first power supply voltage as a drive voltage, a second power supply voltage higher than the first power supply voltage to generate a monitor signal indicating whether or not the first power supply voltage is below a predetermined threshold; a logic unit for generating, using the first power supply voltage as a drive voltage, a reset request signal according to the monitor signal; a reset signal generation unit for generating, using a second power supply voltage as a drive voltage, a reset signal according to the reset request signal; and a driver unit for discharging, using the second power supply voltage as a drive voltage, liquid crystal cells according to the reset signal.

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 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: Proper correction data is set by scanning a test chart even if the test chart has pixel lines formed thereon as inclined with respect to a secondary scanning direction. A virtual line CL is determined in a middle position in a primary scanning direction on the test chart, which extends between center indices 43C and 44C at opposite ends in the secondary scanning direction of the test chart. A scanning lines SL extending parallel to the virtual line CL is set to each pixel line Q. Sampling areas SQ are set on the scanning line SL. Density data is acquired from a plurality of sampling points formed in each sampling area SQ.

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 method is disclosed for testing a light emission condition of an exposing head of a type including a plurality of luminous elements arranged along a main scanning direction for forming a linear dot pattern on a print paper. The exposing head is movable relative to the print paper in a sub scanning direction. The emission amounts of the respective luminous elements are compared to each other, based on the densities of respective dots obtained by exposure on the print paper. For allowing more accurate grasping of the light emission of each luminous element, testing target dots are formed by driving luminous elements selected as target elements which are not adjacent each other in the main scanning direction. Further, background dots are formed in the peripheries of the target dots so that the peripheries are completely filled with the background dots having a density higher than that of the target dots.