An inkjet printer forms ink dots of a first ink and ink dots of a second ink on a recording medium. The inkjet printer performs first screen processing on image data of the second ink to generate a first dot group including the ink dots of the second ink, and performs second screen processing on image data of the second ink to generate a second dot group including the ink dots of the second ink. The inkjet printer forms a first printing layer, on the recording medium, of the ink dots of the first ink and the ink dots of the first dot group, and forms a second printing layer of the ink dots of the second ink, above or below the first printing layer.

An example embodiment may involve obtaining a digital image containing a pixel block. An AM halftone may be configured to be applied to the digital image by default. The example embodiment may also involve deriving, from the pixel block, a bitmap defining foreground and non-foreground pixels of the pixel block. The example embodiment may also involve sequentially scanning horizontal lines of the bitmap to identify clusters of foreground pixels. Each pixel in a particular cluster of the clusters of foreground pixels may be either (i) the only pixel in the particular cluster, or (ii) vertically or horizontally adjacent to another pixel in the particular cluster. The example embodiment may also involve, possibly based on the clusters of foreground pixels identified in the bitmap, applying an FM halftone to the digital image, and causing the digital image to be printed with the applied FM halftone.

There are provided a printing system, a method of generating a halftone processing rule, a method of acquiring a characteristic parameter, image processing device and method, a halftone processing rule, a halftone image, a method of manufacturing a printed material, an ink jet printing system, and a program which are capable of reducing an operation load of a user and acquiring a halftone processing rule appropriate for the printing system. A characteristic parameter acquisition chart (100) including a pattern for acquiring characteristic parameters related to characteristics of the printing system is output, and the output characteristic parameter acquisition chart (100) is read by image reading means. The characteristic parameters are acquired by analyzing the read image of the characteristic parameter acquisition chart (100), and halftone processing rules that define the processing contents of halftone processes used in the printing system are generated based on the acquired characteristic parameters.

An image processing apparatus includes a storage and processing circuitry. The storage is configured to store a dither table in which a plurality of dither patterns are recorded, each of the dither patterns being formed with a halftone dot screen in which an output area ratio that is a proportion of void halftone dots per unit area corresponds to any one of gradation values of image data. The processing circuitry is configured to read a gradation value for each region in image data input for each toner color, decide a dither pattern to be applied to the read gradation value, read out the decided dither pattern from the dither table, and perform dither processing of applying the read dither pattern to the region in the image data.

An image forming system that classifies a block formed by Nb pixels included in image data into Nt groups including a group including a pixel of a highest gradation value and a group including a pixel of a lowest gradation value, generates, for at least one of the Nt groups, positional information that is information indicating positions of pixels that form the corresponding group, determines a block gradation value in accordance with a data amount that is smaller than a data amount that is used for expressing gradation values of the Nb pixels for each of the Nt groups as a target, based on a gradation value for each of pixels that form each group, tentatively determines, determines, for the block as a target, the dot arrangement using the tentatively determined dot arrangement and the positional information, and forms an image using the determined dot arrangement.

Sharpness of image data in a low-frequency component, which is deceased by an image forming apparatus, is recovered and the recovered image data is converted into halftone image data. Halftone processing includes calculating edge intensity in a local region, dividing the local region into a first pixel group and a second pixel group based on a pixel value of each pixel, determining a distribution order of dots based on a pixel value of each pixel, a threshold value, and the edge intensity such that dots are likely to be distributed to the first pixel group and dots are unlikely to be distributed to the second pixel group, and determining an output value for each pixel in the local region by distributing dots to some pixels included in the local region as much as a number of dots to be output to the local region while referring to the distribution order.

The dither mask generation method includes: a process of setting a nozzle relative ejection rate which is a control target of the nozzle ejection rate and stipulates a relative using ratio of the individual nozzles; a process of setting a nozzle pattern indicating correspondence relation between individual pixels of the dither mask and the nozzles in charge of recording at respective pixel positions; a process of setting an upper limit to the nozzle ejection rates of the individual nozzles for each raster in a main scanning direction, regarding at least some thresholds; and a process of setting the thresholds to the pixels of the dither mask based on the nozzle relative ejection rate, the nozzle pattern and a limitation by the upper limit.

A method for generating a data-bearing image is implemented by an encoding system including a halftoning module and an encoding module that stores encoding rules associated with respective codes. In the method, the halftoning module converts a grayscale image into a halftone image having a plurality of image cells each consisting of a plurality of dots, at least one of which is a first-tone dot and each of the rest of which is a second-tone dot. Afterward, the encoding module generates a data-bearing halftone image encoded with at least one of the codes by maintaining or changing the number of the first-tone dots in one of the image cells based on one of the encoding rules associated with the at least one of the codes.

A method of printing includes identifying vertical edges in a halftone image. The method also includes determining whether a lightness of color of a first predetermined area to a left side of a respective vertical edge is substantially equal to, less than, or greater than the lightness of color of a second predetermined area to a right side of the respective vertical edge. The method also includes categorizing respective vertical edges left vertical edges, right vertical edges, and neutral vertical edges to prioritize a print direction thereof.

An example method for forming a data-bearing medium in accordance with aspects of the present disclosure includes setting variables associated with the data-bearing medium, the variables comprising a bit length of a codeword, identifying a phase-invariant codeword based on the variables, and arranging rows of the data-bearing medium with the phase-invariant codewords.