Abstract: A coil spring includes a wire rod and an elastic coat provided on the wire rod. The coil spring includes a coil section including a plurality of coil portions. The wire rod includes a round cross-sectional portion, a cross-section varying portion, and a rectangular cross-sectional portion along the longitudinal direction of the wire rod. The cross section of the rectangular cross-sectional portion is substantially square and has a first plane and a second plane. The first plane and the second plane oppose each other in the coil section. The elastic coat is provided on at least one of the first plane and the second plane. The elastic coat is continuous from the round cross-sectional portion to the cross-sectional variation portion and the rectangular cross-sectional portion.

Abstract: The inkjet printing apparatus is configured to be able to execute a batch adjustment process of performing a plurality of times of adjustment processes related to printing in succession based on one instruction from an outside. The conveyance control unit maintains the conveyance speed at a first speed in a period when a chart printing process is performed and a period when a chart imaging process is performed. The conveyance control unit decreases the conveyance speed from the first speed to the second speed after the end of the chart imaging process in an adjustment process except for an adjustment process that is performed last in the batch adjustment process, and increases the conveyance speed from the second speed to the first speed before the start of the chart printing process in an adjustment process that is performed next.

Abstract: The ratios (Wp1/Wm1, Wp2/Wm2) of the pattern widths Wp1, Wp2 to the paper widths Wm1, Wm2 are obtained, respectively, after the first drying and after the second drying (Step S109). Then, in accordance with these ratios, a range (in other words, the width) in which the back print image G2 is to be printed is adjusted in the width direction Aw (Step S204). As a result, when the double-sided printing is performed on the continuous form paper M by performing drying every time when the image is printed on each of the surfaces Ma, Mb of the continuous form paper M, it is possible to suppress the difference in the ratios of the widths of the images G1, G2 to the width of the continuous form paper M between the surfaces Ma and Mb of the continuous form paper M.

Abstract: A printing apparatus for printing on a front surface of a printing medium, and thereafter printing on a back surface of the printing medium. The apparatus includes the following elements: a front surface print head for printing a front surface image based on front surface image data, over a surface page length on the front surface of the printing medium; a back surface print head for printing a back surface image based on back surface image data, on the back surface of the printing medium; a data corrector for creating corrected front surface image data by correcting an image size of the front surface image data based on elasticity information in the transport direction; and a printing controller for causing printing based on the corrected front surface image data, and controlling the back surface print head to perform printing on the back surface.

Abstract: A printing apparatus for printing on a front surface of a printing medium, and thereafter printing on a back surface of the printing medium. The apparatus includes the following elements: a front surface print head for printing a front surface image based on front surface image data, over a surface page length on the front surface of the printing medium; a back surface print head for printing a back surface image based on back surface image data, on the back surface of the printing medium; a data corrector for creating corrected front surface image data by correcting an image size of the front surface image data based on elasticity information in the transport direction; and a printing controller for causing printing based on the corrected front surface image data, and controlling the back surface print head to perform printing on the back surface.

Abstract: A printing apparatus of this invention scans with a tester a testing chart printed by a printing controller to acquire testing image data. A total amount of displacement calculator calculates an amount of displacement of a recording position including a direction of misregister as a total amount of displacement, based on a large amount of displacement determined by a large amount of displacement determiner, a direction of displacement detected by a direction of displacement detector, a shift amount corresponding to an amount of displacement detecting chart determined by an amount of displacement detecting chart determiner, and a peak position of the amount of displacement detecting chart determined by the amount of displacement detecting chart determining unit. Thus, since a total amount of displacement of the misregister can be calculated only by printing the testing chart on web paper WP, an amount of displacement of the misregister in the transport direction can be obtained easily in a short time.

Abstract: The present application discloses an inkjet printing device in which a nozzle that caused a print defect, such as an ejection failure, is reliably identified by a simple process even when an end of a test pattern is not recorded. In a configuration example of the inkjet printing device, a test pattern TPat to be printed for identifying a recording head nozzle that caused a print defect consists of an ejection failure detection pattern DPat and a position detection pattern PPat. The position detection pattern PPat consists of a position mark PM4 and pairs of position marks (PM1 and PM1; PM2 and PM2; and PM3 and PM3) symmetrically arranged with respect to the position mark PM4 in a sheet width direction. Each position mark consists of three linear patterns having the same length and disposed at equal intervals. Moreover, the position detection pattern PPat is configured such that linear pattern length decreases with increasing distance from a center position mark.

Abstract: A nozzle operating situation checking method for inkjet printing apparatus which perform printing by dispensing ink droplets from a printing head having a plurality of nozzles arranged in a transverse direction of a printing medium. The method includes the following steps: a step of printing a testing chart; a step of reading the testing chart downstream of the printing head; a step of extracting grid boxes; a step of deriving a standard width from width sizes; a step of detecting a box having a width size equal to or larger than a corrected standard width by comparing the width sizes of the respective boxes with the corrected standard width; and a step of determining that a missing nozzle exists upon detection of the box having a width size equal to or larger than the corrected standard width.

Abstract: The present application discloses an inkjet printing device in which a nozzle that caused a print defect, such as an ejection failure, is reliably identified by a simple process even when an end of a test pattern is not recorded. In a configuration example of the inkjet printing device, a test pattern TPat to be printed for identifying a recording head nozzle that caused a print defect consists of an ejection failure detection pattern DPat and a position detection pattern PPat. The position detection pattern PPat consists of a position mark PM4 and pairs of position marks (PM1 and PM1; PM2 and PM2; and PM3 and PM3) symmetrically arranged with respect to the position mark PM4 in a sheet width direction. Each position mark consists of three linear patterns having the same length and disposed at equal intervals. Moreover, the position detection pattern PPat is configured such that linear pattern length decreases with increasing distance from a center position mark.

Abstract: A head voltage correcting method for inkjet printing apparatus which perform printing with a head having a plurality of head modules includes the following steps: a testing chart printing step for printing testing charts which includes a lowest density head module check pattern, satellite check patterns, band-by-band density variable patterns, and in-band density variable patterns; a lowest density head module determining step for determining a lowest density head module; a satellite-free drive voltage determining step; and a new reference voltage determining step for determining a drive voltage of the band-by-band density variable patterns of the adjacent head module to be a new reference voltage for the adjacent head module.

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 nozzle operating situation checking method for inkjet printing apparatus which perform printing by dispensing ink droplets from a printing head having a plurality of nozzles arranged in a transverse direction of a printing medium. The method includes the following steps: a step of printing a testing chart; a step of reading the testing chart downstream of the printing head; a step of extracting grid boxes; a step of deriving a standard width from width sizes; a step of detecting a box having a width size equal to or larger than a corrected standard width by comparing the width sizes of the respective boxes with the corrected standard width; and a step of determining that a missing nozzle exists upon detection of the box having a width size equal to or larger than the corrected standard width.

Abstract: A head voltage correcting method for inkjet printing apparatus which perform printing with a head having a plurality of head modules includes the following steps: a testing chart printing step for printing testing charts which includes a lowest density head module check pattern, satellite check patterns, band-by-band density variable patterns, and in-band density variable patterns; a lowest density head module determining step for determining a lowest density head module; a satellite-free drive voltage determining step; and a new reference voltage determining step for determining a drive voltage of the band-by-band density variable patterns of the adjacent head module to be a new reference voltage for the adjacent head module.

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 printing apparatus of this invention scans with a tester a testing chart printed by a printing controller to acquire testing image data. A total amount of displacement calculator calculates an amount of displacement of a recording position including a direction of misregister as a total amount of displacement, based on a large amount of displacement determined by a large amount of displacement determiner, a direction of displacement detected by a direction of displacement detector, a shift amount corresponding to an amount of displacement detecting chart determined by an amount of displacement detecting chart determiner, and a peak position of the amount of displacement detecting chart determined by the amount of displacement detecting chart determining unit. Thus, since a total amount of displacement of the misregister can be calculated only by printing the testing chart on web paper WP, an amount of displacement of the misregister in the transport direction can be obtained easily in a short time.