Abstract: An inkjet printing apparatus includes a plurality of nozzles for discharging ink, a CIS (Contact Image Sensor) type scanner for reading, as image data, charts for correction printed in the ink discharged from the nozzles, light emitters for emitting light to the charts for correction, a scanner controller for causing the scanner to scan the charts for correction with a plurality of read conditions, a correction table creator for creating nozzle shading correction tables based on the image data read, and a shading corrector for carrying out shading correction for the nozzles based on the correction tables.

Abstract: A white reference value and a corresponding transport speed are stored in memory. A black reference value and a corresponding imaging speed are also stored. Next, a printing operation is started and color values and a corresponding transport speed are stored. Accurately corrected color values are derived from the stored white reference value, transport speed, black reference value, imaging speed, color values and transport speed.

Abstract: A printed tone control method for adjusting a printed color tone by comparing image data serving as a reference and image data obtained by reading an image from a print actually made by a printing machine. The method includes a representative point setting step for setting a representative point for use in control of the color tone based on image data, an alternative representative point setting step for setting an alternative representative point that satisfies a predetermined condition when a point inappropriate for tone measurement is selected as the representative point, and a tone adjusting step for adjusting the color tone by using the alternative representative point.

Abstract: A printing machine control method according to this invention includes a platemaking step for making a printing plate having, formed thereon, a test pattern with different dot percentages for areas corresponding to ink keys, a first printing step for making prints by using the printing plate; a first density measuring step for measuring and storing, at intervals of time, density of the test pattern on printing paper, a second printing step for making prints after changing opening of the ink keys, a second density measuring step for measuring and storing, at intervals of time, density of the test pattern on printing paper, and a control step for correcting an amount of change in the opening of the ink keys based on the density measured in the first density measuring step and the density measured in the second density measuring step, and correcting an interval between changes in the opening of the ink keys based on a time taken until stabilization of the density measured in the second density measuring step.

Abstract: The disclosed method and apparatus execute a printing step for setting a printing condition concerning at least one of a printing machine, a dot pattern, printing paper and ink, and printing an image having a plurality of different dot percentages with the printing condition set; a profile creating step for creating a profile showing printing stability in form of a relationship between the printing condition and each of the dot percentages by measuring a print image obtained in the printing step; a calculating step for deriving printing stability for each color area of an image to be printed, from image data of the image to be printed, the printing condition in time of printing and the profile; and a displaying step for displaying the printing stability of each color area, obtained in the calculating step, of the image to be printed.

Abstract: A printed tone control method for adjusting a printed color tone by comparing image data serving as a reference and image data obtained by reading an image from a print actually made by a printing machine. The method includes a representative point setting step for setting a representative point for use in control of the color tone based on image data, an alternative representative point setting step for setting an alternative representative point that satisfies a predetermined condition when a point inappropriate for tone measurement is selected as the representative point, and a tone adjusting step for adjusting the color tone by using the alternative representative point.

Abstract: A printing plate developing method includes an image recording step for recording an image on a printing plate with an image recorder, an ink key opening degree setting step for setting opening degrees of ink keys in an ink feeder such that the larger opening degree is set for the smaller image percentage in regions, corresponding to the respective ink keys, on the printing plate having the image recorded thereon, a preliminary ink feeding step for feeding the ink to the ink rollers, an ink transfer step for transferring the ink from the ink rollers to the dampening water rollers, a dampening water feeding step for feeding the dampening water to the printing plate with the dampening water rollers, an ink feeding step for feeding the ink to the printing plate with the ink rollers, and a transfer step for transferring the ink from the printing plate to printing paper.

Abstract: An ink feeding rate control method for a printing machine includes a step of determining, from image data used in recording images, an average of image area ratios of images in areas on prints corresponding to ink keys, a step of determining, from the image data, an average of image area ratios of images in positions aligned in a printing direction with the detecting patches (i.e. rectangular areas having substantially the same width as the detecting patches and extending in the printing direction) printed in the areas on the prints corresponding to the ink keys, and a step of correcting the reference information based on the average of image area ratios of the images in the areas on the prints corresponding to the ink keys, and the average of image area ratios of the images in the positions aligned in the printing direction with the detecting patches printed on the prints.

Abstract: There is provided a patch measurement device which, even if the position of a patch in a control strip printed on a printed material is incorrectly detected, does not affect the controlling of the printing apparatus. A data storage section 271 in a patch measurement device 27 stores printed-image data Dpd. A reference mark detection section 272 detects a reference mark rm in the printed-image data Dpd, and generates position data thereof. A reference mark position data comparison section 273 compares the position data against past position data stored in a reference mark position data storage section 274 to determine the validity of the position data. If the position data is valid, a patch position detection section 275 detects a patch whose color density is to be measured. A color density measurement section 276 generates color density measurement data of the printed patch.

Abstract: A printing control scale for use in printing in two or three color inks with a printing machine capable of multicolor printing using four color inks. The printing control scale includes two or three types of detecting patches printed in the two or three color inks. These detecting patches are arranged in positions respectively corresponding to four types of detecting patches printed when the four color inks are used. Regions printed in a combination of the two or three color inks are formed in positions corresponding to other detecting patches.

Abstract: An ink feeding method includes a density reading step for reading density data obtained by measuring densities of detecting patches on a first image, before an end of a printing operation, a first computing step for computing, from the density data, an ink feed film thickness remaining after prints having the first image are made, a second computing step for computing an ink feed film thickness required for making prints having a second image, from a target density for the prints having the second image, a third computing step for computing a preset ink feeding rate from the ink feed film thickness remaining after the prints having the first image are made, computed in the first computing step, and the ink feed film thickness required for making the prints having the second image, computed in the second computing step, and an ink feeding step for feeding the preset ink based on the preset ink feeding rate computed in the third computing step.

Abstract: Densities of detecting patches also called control scales printed on prints in a first print job are used to control the feed rate of dampening water in a second print job following the first print job. Specifically, densities of detecting patches on the prints obtained from the first print job are measured, and a feed rate of dampening water is calculated from the densities of the detecting patches. A base feed rate of dampening water is calculated based on the feed rate calculated and a humidity and temperature occurring when the first print job is performed. A proper feed rate of dampening water is calculated based on the base feed rate and a humidity and temperature occurring when the second print job is performed.

Abstract: A white reference value and a corresponding transport speed are stored in memory. A black reference value and a corresponding imaging speed are also stored. Next, a printing operation is started and color values and a corresponding transport speed are stored. Accurately corrected color values are derived from the stored white reference value, transport speed, black reference value, imaging speed, color values and transport speed.

Abstract: A print defect displaying method for displaying a defect on prints based on image data obtained by successively reading images from the prints. The method includes a first imaging step for obtaining first image data having a first resolution by reading an image from a first print, a defect detecting step for detecting a defect on the prints by comparing the image data obtained in the first imaging step and reference image data, a second imaging step for obtaining second image data having a second resolution higher than the first resolution, by reading an image from an area, including the defect detected in the defect detecting step, on a second print produced after the first print, and an enlarged image displaying step for displaying in enlargement the area including the defect based on the second image data.

Abstract: First, densities are measured of a set of detecting patches having an equal number of lines and different area ratios between a printing area and a non-printing area, a set of detecting patches having an equal area ratio between a printing area and a non-printing area and different numbers of lines, and solid patches. Next, area ratios S relating to quantities of dampening water are calculated by using density of the set of detecting patches having the equal number of lines and different area ratios between the printing area and non-printing area, and density of the solid patches. Then, coefficients N relating to emulsification rates of ink are calculated by using density of the set of detecting patches having the equal area ratio between the printing area and non-printing area and different numbers of lines, and the density of the solid patches. Finally, a feed rate of dampening water is adjusted by using the area ratios S and coefficients N.

Abstract: Densities of detecting patches also called control scales printed on prints in a first print job are used to control the feed rate of dampening water in a second print job following the first print job. Specifically, densities of detecting patches on the prints obtained from the first print job are measured, and a feed rate of dampening water is calculated from the densities of the detecting patches. A base feed rate of dampening water is calculated based on the feed rate calculated and a humidity and temperature occurring when the first print job is performed. A proper feed rate of dampening water is calculated based on the base feed rate and a humidity and temperature occurring when the second print job is performed.

Abstract: An ink feeding method includes a density reading step for reading density data obtained by measuring densities of detecting patches on a first image, before an end of a printing operation, a first computing step for computing, from the density data, an ink feed film thickness remaining after prints having the first image are made, a second computing step for computing an ink feed film thickness required for making prints having a second image, from a target density for the prints having the second image, a third computing step for computing a preset ink feeding rate from the ink feed film thickness remaining after the prints having the first image are made, computed in the first computing step, and the ink feed film thickness required for making the prints having the second image, computed in the second computing step, and an ink feeding step for feeding the preset ink based on the preset ink feeding rate computed in the third computing step.

Abstract: First, densities are measured of a set of detecting patches having an equal number of lines and different area ratios between a printing area and a non-printing area, a set of detecting patches having an equal area ratio between a printing area and a non-printing area and different numbers of lines, and solid patches. Next, area ratios S relating to quantities of dampening water are calculated by using density of the set of detecting patches having the equal number of lines and different area ratios between the printing area and non-printing area, and density of the solid patches. Then, coefficients N relating to emulsification rates of ink are calculated by using density of the set of detecting patches having the equal area ratio between the printing area and non-printing area and different numbers of lines, and the density of the solid patches. Finally, a feed rate of dampening water is adjusted by using the area ratios S and coefficients N.

Abstract: A color density measuring step is executed for measuring color densities of unprinted areas on prints. Then, a determining step is executed for determining from the color densities of the unprinted areas on the prints whether ink tinting has occurred. When the determining step determines that ink tinting has occurred, a dampening water adjusting step is executed for adjusting a dampening water feeding rate after feeding dampening water in an increased rate once. A variation in the ink feeding rate is prohibited for a predetermined waiting time after feeding dampening water in the increased rate once in the dampening water adjusting step.

Abstract: An ink feeding rate control method for a printing machine includes a step of determining, from image data used in recording images, an average of image area ratios of images in areas on prints corresponding to ink keys, a step of determining, from the image data, an average of image area ratios of images in positions aligned in a printing direction with the detecting patches (i.e. rectangular areas having substantially the same width as the detecting patches and extending in the printing direction) printed in the areas on the prints corresponding to the ink keys, and a step of correcting the reference information based on the average of image area ratios of the images in the areas on the prints corresponding to the ink keys, and the average of image area ratios of the images in the positions aligned in the printing direction with the detecting patches printed on the prints.