Abstract: An image shifter creates plural pairs of shift image data. A shading corrector and a halftone dot processor create halftone shift image data from shift images. Further, a difference image creator creates halftone common image data which is a common part of a pair of halftone shift image data, and creates halftone positive difference image data and halftone negative difference image data each of which is a difference between the halftone common image data and one of a pair of halftone shift image data. A composite image creator synthesizes the halftone common image data corresponding to an amount of positional deviation, and the halftone positive difference image data or halftone negative difference image data. A controller executes printing on web paper. Since the image data is only synthesized, processing load can be lightened even if printing is performed to restrain positional deviations.

Abstract: An image shifter creates plural pairs of shift image data. A shading corrector and a halftone dot processor create halftone shift image data from shift images. Further, a difference image creator creates halftone common image data which is a common part of a pair of halftone shift image data, and creates halftone positive difference image data and halftone negative difference image data each of which is a difference between the halftone common image data and one of a pair of halftone shift image data. A composite image creator synthesizes the halftone common image data corresponding to an amount of positional deviation, and the halftone positive difference image data or halftone negative difference image data. A controller executes printing on web paper. Since the image data is only synthesized, processing load can be lightened even if printing is performed to restrain positional deviations.

Abstract: A head voltage correcting method for inkjet printing apparatus which perform printing by dispensing ink droplets from a head to a printing medium. The method includes the following steps: a step of printing testing charts; a step of acquiring images of the testing charts; a step of determining presence or absence of satellite droplets for each drive voltage; a step of obtaining distances between the main droplets and the satellite droplets for each drive voltage; a step of obtaining a distance reference drive voltage from a relationship of the distances for each drive voltage and a distance threshold; a step of obtaining ink droplet sizes for each drive voltage; a step of obtaining a size reference drive voltage; and a step of comparing the distance reference drive voltage and the size reference drive voltage, and making correction by adopting a larger one as the reference voltage.

Abstract: An image processing apparatus for a printing apparatus. The image processing apparatus includes a recording position acquiring device for acquiring recording positions of a reference image printed by a reference print head and a target image printed by a target print head, a positional deviation amount calculating device for calculating a deviation amount due to a skew with respect to the recording positions of the reference image and the target image, and a positional deviation interpolation image converting device, when there is a remainder of the deviation amount and the predetermined intervals, for adding a weight based on the remainder, and adding a smaller weight than the weight to the reference image or the target image without a remainder and adjoining the reference image or the target image with the remainder, thereby converting the image into a width direction positional deviation interpolation image.

Abstract: A head voltage correcting method for inkjet printing apparatus which perform printing by dispensing ink droplets from a head to a printing medium. The method includes the following steps: a step of printing testing charts; a step of acquiring images of the testing charts; a step of determining presence or absence of satellite droplets for each drive voltage; a step of obtaining distances between the main droplets and the satellite droplets for each drive voltage; a step of obtaining a distance reference drive voltage from a relationship of the distances for each drive voltage and a distance threshold; a step of obtaining ink droplet sizes for each drive voltage; a step of obtaining a size reference drive voltage; and a step of comparing the distance reference drive voltage and the size reference drive voltage, and making correction by adopting a larger one as the reference voltage.

Abstract: A correction value acquiring method for inkjet printing apparatus includes the following steps: a testing chart forming step for forming a testing chart in one printing job, the testing chart including a first line segment group having a plurality of first line segments formed by causing a drive circuit of a head module acting as reference to output a reference drive signal for obtaining a reference density, and a second line segment group having a plurality of second line segments formed by causing drive circuits of head modules other than the head module acting as reference to output the reference drive signal and drive signals with a plurality of different correction values added to the reference drive signal; an identifying step for identifying from the testing chart a second line segment having a density matching with that of a first line segment; and a correction value acquiring step for acquiring a correction value corresponding to the second line segment identified.

Abstract: An image processing apparatus for a printing apparatus. The image processing apparatus includes a recording position acquiring device for acquiring recording positions of a reference image printed by a reference print head and a target image printed by a target print head, a positional deviation amount calculating device for calculating a deviation amount due to a skew with respect to the recording positions of the reference image and the target image, and a positional deviation interpolation image converting device, when there is a remainder of the deviation amount and the predetermined intervals, for adding a weight based on the remainder, and adding a smaller weight than the weight to the reference image or the target image without a remainder and adjoining the reference image or the target image with the remainder, thereby converting the image into a width direction positional deviation interpolation image.

Abstract: A correction value acquiring method for inkjet printing apparatus includes the following steps: a testing chart forming step for forming a testing chart in one printing job, the testing chart including a first line segment group having a plurality of first line segments formed by causing a drive circuit of a head module acting as reference to output a reference drive signal for obtaining a reference density, and a second line segment group having a plurality of second line segments formed by causing drive circuits of head modules other than the head module acting as reference to output the reference drive signal and drive signals with a plurality of different correction values added to the reference drive signal; an identifying step for identifying from the testing chart a second line segment having a density matching with that of a first line segment; and a correction value acquiring step for acquiring a correction value corresponding to the second line segment identified.

Abstract: An image processing apparatus for a printing apparatus. The image processing apparatus includes a recording position acquiring device for acquiring recording positions of a reference image printed by a reference print head and a target image printed by a target print head, a positional deviation amount calculating device for calculating a deviation amount due to a skew with respect to the recording positions of the reference image and the target image, and a positional deviation interpolation image converting device, when there is a remainder of the deviation amount and the predetermined intervals, for adding a weight based on the remainder, and adding a smaller weight than the weight to the reference image or the target image without a remainder and adjoining the reference image or the target image with the remainder, thereby converting the image into a width direction positional deviation interpolation image.

Abstract: Image data is accurately resized in real time by downscaling. An image signal generating apparatus includes a parameter generator that dynamically generates a parameter PM and an image signal generator that repeats processing of generating an output image signal Q in response to each sampling signal B. Each parameter includes a division ratio parameter DP. The division ratio parameter DP corresponds to a ratio of a second time period Tb and a third time period Tc other than the second time period Tb. The second time period Tb is a time interval until the generation of a sampling signal Bn in a first time period Ta until input of an immediate timing signal Ak+1 since input of a last timing signal Ak. The image signal generator repeatedly generates a first weighted signal and a second weighted signal of the image signal in response to each sampling signal Bn.

Abstract: A drive circuit for driving a plurality of nozzles to discharge ink droplets. The testing chart comprises a contrast chart including a first line segment group having first line segments formed by causing the drive circuit to output a reference drive signal for a density serving as reference, thereby to make discharge from a first number of driven nozzles, the first line segments extending in a direction perpendicular to a transport direction and arranged at predetermined intervals, and a second line segment group having second line segments formed by causing the drive circuit to output a drive signal for driving only a selected number of nozzles as target of correction less than the first number of driven nozzles, the second line segments being formed between the first line segments while changing the correction values for correcting the drive signal of the drive circuit.

Abstract: An image processing apparatus for a printing apparatus. The image processing apparatus includes a recording position acquiring device for acquiring recording positions of a reference image printed by a reference print head and a target image printed by a target print head, a positional deviation amount calculating device for calculating a deviation amount due to a skew with respect to the recording positions of the reference image and the target image, and a positional deviation interpolation image converting device, when there is a remainder of the deviation amount and the predetermined intervals, for adding a weight based on the remainder, and adding a smaller weight than the weight to the reference image or the target image without a remainder and adjoining the reference image or the target image with the remainder, thereby converting the image into a width direction positional deviation interpolation image.

Abstract: Disclosed is an inspecting chart including a reference pattern containing a first line segment group and a second line segment group, a first-side deviation pattern, and a second-side deviation pattern. The first line segment group is formed by a plurality of first line segments printed by a reference printing head at a first given interval. The second line segment is formed by second line segments printed by a printing head on a center between two adjacent first line segments or a center of each of the first line segments, the printing head being spaced away from the reference printing head in the transportation direction of a print medium. The first-side deviation pattern and the second-side deviation pattern are printed with various deviations.

Abstract: A drive circuit for driving a plurality of nozzles to discharge ink droplets. The testing chart comprises a contrast chart including a first line segment group having first line segments formed by causing the drive circuit to output a reference drive signal for a density serving as reference, thereby to make discharge from a first number of driven nozzles, the first line segments extending in a direction perpendicular to a transport direction and arranged at predetermined intervals, and a second line segment group having second line segments formed by causing the drive circuit to output a drive signal for driving only a selected number of nozzles as target of correction less than the first number of driven nozzles, the second line segments being formed between the first line segments while changing the correction values for correcting the drive signal of the drive circuit.

Abstract: An image processor of a printing apparatus including a first printing head having recording units spaced at a given interval orthogonal to a transportation direction of a print medium and spaced along the transportation direction of the print medium, a second printing head disposed downstream of the first printing head, a device for obtaining recording positions of first and second images printed with the first and second printing heads, a device for calculating a positional shift amount between the recording positions of the first and second images, and a positional shift interpolating image converter performing weighting, if a remainder is generated through division of the positional shift amount by the given interval, to the first or second image depending on the remainder to convert the first or second image into a positional shift interpolating image having been shifted in accordance with skew of the print medium.

Abstract: Provided is a printing method of performing printing onto a recording medium to be transported with a plurality of recording element arrays. The printing method includes a storing step of storing a perimeter of a timing roller upon acquiring correction data in association with the correction data, an obtaining step of obtaining the perimeter during printing after the storing step of storing the perimeter upon acquiring the correction data, and a modifying step of modifying the correction data during the printing in accordance with the perimeter upon acquiring the correction data and the perimeter during the printing.

Abstract: Disclosed is an inspecting chart including a reference pattern containing a first line segment group and a second line segment group, a first-side deviation pattern, and a second-side deviation pattern. The first line segment group is formed by a plurality of first line segments printed by a reference printing head at a first given interval. The second line segment is formed by second line segments printed by a printing head on a center between two adjacent first line segments or a center of each of the first line segments, the printing head being spaced away from the reference printing head in the transportation direction of a print medium. The first-side deviation pattern and the second-side deviation pattern are printed with various deviations.

Abstract: Disclosed is a printing apparatus that performs printing onto a print medium including a transporting device that transports a print medium, a plurality of printing heads, a photographing unit that photographs the print medium, a shift detecting chart forming device, and a correcting device. The shift detecting chart forming device forms a shift detecting chart having a first line segment group consisting of first line segments that are printed onto the print medium at given intervals in an orthogonal direction with respect to the transportation direction with a reference printing head, and a second line segment group formed along the first line segment group, and consisting of second line segments that are printed with a subsequent printing head. The correcting device corrects a printing timing with the subsequent printing head relative to the reference printing head in accordance with a density variation of the photographed shift detecting chart.

Abstract: Disclosed is a printing apparatus that performs printing onto a print medium including a transporting device that transports a print medium, a plurality of printing heads, a photographing unit that photographs the print medium, a shift detecting chart forming device, and a correcting device. The shift detecting chart forming device forms a shift detecting chart having a first line segment group consisting of first line segments that are printed onto the print medium at given intervals in an orthogonal direction with respect to the transportation direction with a reference printing head, and a second line segment group formed along the first line segment group, and consisting of second line segments that are printed with a subsequent printing head. The correcting device corrects a printing timing with the subsequent printing head relative to the reference printing head in accordance with a density variation of the photographed shift detecting chart.

Abstract: A screening output density corrector of an image processor corrects output densities of a plurality of types of dotted pattern data stored in a screening data storage upon printing. A dotted image data generator uses a plurality of types of the dotted pattern data subjected to the output density correction for performing screening processing to each of images, the images being represented by the continuous tone image data. Consequently, the dotted image data generator generates dotted image data of the images with the corrected output density. Accordingly, output density correction is made not to the continuous tone image data but to the dotted pattern data. Consequently, uniformity of the discharge characteristic (the number of ink droplets) is obtainable upon printing with different types of dotted pattern data. This allows prevention of unevenness in printing through the screening processing based on a plurality of types of dotted pattern data.