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.

An example operating method of an image forming apparatus includes detecting a position change of a beam with respect to a certain color in a main scanning direction, based on a change in a detection time at which the beam with respect to the certain color is detected by a beam detecting apparatus in the main scanning direction, detecting a position change of the beam with In respect to the certain color in a sub-scanning direction, based on a change in a detection time at which the beam with respect to the certain color is detected by the beam detecting apparatus in the sub-scanning direction, and correcting a value of at least one parameter used for alignment between an image of a reference color and an image of the certain color, based on the position changes of the beam in the main scanning direction and the sub-scanning direction.

An image forming apparatus includes a rotatable image bearer, a transfer rotator, a detector, and circuitry. The image bearer bears an image. The transfer rotator transfers the image from the image bearer onto a recording medium sandwiched and conveyed between the image bearer and the transfer rotator. The detector detects length information indicating a length, in a direction of conveyance of the recording medium, of the image on the recording medium. The circuitry corrects a correction value, based on the length information detected by the detector and a target value of the length information, to correct an image magnification, in the direction of conveyance of the recording medium, of the image to be formed on the recording medium. The circuitry controls an image forming operation of forming the image on the recording medium with the correction value.

Methods of controlling an inkjet printer are disclosed. The methods include defining shape information using a design graphics system. The shape information includes fill colors for shapes, and may include colors for edges. The colors are interpreted as one or more attributes, such as film thickness or material, for a film to be formed on a substrate.

There is provided an image forming apparatus that forms an image with a plurality of coloring materials on a recording medium, and the image forming apparatus includes: a hardware processor that calculates a chromaticity range having a color difference not less than a setting value to respective chromaticities of the plurality of coloring materials for use in formation of the image, as a base color range common between the plurality of coloring materials.

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.

In an example, there is provided a method and apparatus for controlling spit on page operation, the method comprising receiving at least one image to be printed, for each row of a plurality of rows of the image: identifying two or more pixels of the row of the image to be printed by a nozzle of a printhead, determining if a spacing between two consecutive pixels of the two or more pixels is greater than a threshold distance, and in response to a determination that the spacing between the two consecutive pixels is greater than the threshold distance, providing an indication that spit on page dots should be provided when printing the image.

An object of the present invention is to efficiently perform a reading operation for printing position adjustment with high accuracy. A printing apparatus prints, on a print medium, adjustment patterns for adjusting a printing position on the print medium and corresponding respectively to printing position adjustment items. In this printing, the printing apparatus prints the adjustment patterns while conveying the print medium in a forward direction with a conveying unit. Then, the conveying unit conveys the print medium in a backward direction until the adjustment patterns are moved beyond a reading position of a reading unit in the backward direction. Thereafter, the conveying unit conveys the print medium in the forward direction again to cause the adjustment patterns to reach the reading position. Thereafter, the reading unit reads the adjustment patterns continuously at the reading position while the conveying unit conveys the print medium in the forward direction.

An image forming device which forms an image for color correction in the margin of a continuous recording medium such as continuous paper as appropriate without causing erroneous detection by a mark sensor at a post-processing stage. In the image forming device, a printing data generator (control section) performs: acquiring a detection criterion to detect a post-processing image for use at the post-processing stage; creating a color correction image to be used for color correction of an original image according to the detection criterion; and arranging the color correction image as an outer area image in an area other than an original image formation area in printing data.

A printing apparatus includes a print execution section and a controller. The print execution section includes: a printing head having nozzles from which ink is discharged; a main-scan section configured to execute main-scan in which the printing head moves along a main-scan direction relative to a printing medium; and a sub-scan section configured to execute sub-scan in which the printing medium moves along a sub-scan direction relative to the printing head. The controller obtains object image data indicating an object image formed by pixels, generates pieces of partial printing data by processing the object image data in an order from a downstream side toward an upstream side in the sub-scan direction, and causes the print execution section to execute, a plurality of times, the sub-scan and partial printing in which ink is discharged from the printing head during the main-scan by use of the pieces of partial printing data.