A method of printing an image using a printing system having first and second printheads supplied with a same ink. The method includes the steps of: allocating first lines of the image to the first printhead; allocating second lines of the image to the second printhead; dithering the first lines of the image using a selected first dither mask; dithering the second lines of the image using a selected second dither mask; printing the dithered first lines of the image using the first printhead; and printing the dithered second lines of the image using the second printhead. The first and second dither masks are selected based on a relative alignment of the first and second printheads.

In an image forming device, a controller converts continuous-tone image data to raster image data using a dither matrix. The continuous-tone image data includes pixels each has a tone value. The raster image data is binary image data corresponding to exposure areas. The dither matrix includes threshold values. The dither matrix is configured so that as an exposure area percentage of the raster image data increases, growth of the exposure area progresses according to a growth process including: a stage at which an exposure area extends in a predetermined screen direction from an isolated exposure area to connect with another isolated exposure area; and a stage at which after the isolated exposure area connects with another isolated exposure area, the exposure area extends in a crossing direction crossing the predetermined screen direction. The controller controls the exposure device to expose the photosensitive drum based on the raster image data.

An image forming apparatus includes: a correction unit configured to correct a tone of each pixel in first image data in accordance with an image height on a photosensitive member, and output second image data; a halftone processing unit configured to determine exposed regions of pixels in an image by applying halftone processing to the second image data; and a scanning unit configured to form a latent image by scanning the photosensitive member with light that changes in scanning speed in accordance with an image height based on the exposed regions of the pixels. The scanning unit is further configured to perform partial exposure with respect to the pixels based on the exposed regions of the pixels, the partial exposure exposing partial regions of the pixels to light unlike entire exposure that exposes entire regions of the pixels to light.

A method of screening a continuous-tone image is configured to produce an output image to be printed on a surface. The continuous-tone image comprises a plurality of pixels having respective corresponding intended print locations. The method includes selecting a first sequence comprising a subset of the plurality of intended print locations, the first sequence being selected based on properties of the plurality of intended print locations.

For each intended print location in the first sequence, the method also includes identifying the corresponding pixel in the continuous-tone image to obtain a second sequence for an error diffusion process comprising the identified corresponding pixels in the continuous-tone image.

A printing apparatus that is capable of executing, based on printing data, printing onto a first side of a printing medium and printing onto a second side, which is the back side of the first side, after the printing onto the first side is provided. A print density of a predetermined region at a rear end of the printing medium in a transporting direction at a time of printing of the first side is identified based on the printing data. Conversion data, which is a conversion coefficient to make the identified print density equal to or lower than a predetermined density, is acquired. The printing data is converted by means of the conversion data. Printing onto the first side is executed based on the converted printing data.

There is provided an ink-deposition device suitable for depositing ink on a target surface and a printing system comprising the same. In operation in a printing system, the ink-deposition device can convert digital images into ink images on the target surface using pixel-masks and methods as disclosed herein. Advantageously, the ink-deposition device, the printing system comprising it and the methods of using the same can reduce or prevent the occurrence of some undesired ink-formations typically governed by the respective physical and/or chemical properties of the surface and ink being used or mitigate their effect on print quality. Application of the pixel-image mask yields a binary image that exhibits pixel-clusters with stochastically distributed centroids.

The invention provides an image forming device, which can generate a multi-valued image based on a binary image. An image forming device includes: an image acquisition part for acquiring a binary image; and a multi-valued image generation part generating a multi-valued image including a specific pixel based on pixel values of pixels within a first image region with a first size including the specific pixel and pixel values of pixels within a second image region with a second size different from the first size including the specific pixel in the binary image.

An image processing device includes a dithering circuit, a gradation correction pattern generating circuit, and a gradation correction pattern correcting circuit. The dithering circuit performs a dithering process on image data to generate dithered image data. The gradation correction pattern generating circuit sets, in multi-valued data, gradation information of each of pixels of the generated dithered image data, and generates a gradation correction pattern imitating the dithered image data. The gradation correction pattern correcting circuit performs pattern matching on the generated gradation correction pattern, and corrects the generated gradation correction pattern in accordance with a result of the pattern matching.

A printing system and a printing method are provided. The user terminal includes a print content processing unit and a sliding print content conversion unit, and the handheld printer includes an inkjet printing unit that performs inkjet printing at a predetermined inkjet width in a sliding direction when performing sliding print. The print content processing unit determines the number of sliding print motions and sequentially generates bitmaps corresponding to the respective sliding print motions based on the respective print content mode and the inkjet width, and generates bitmap format instructions corresponding to the respective bitmaps. The sliding print content conversion unit converts pixels in the bitmaps into binary data to form sliding print content. The handheld printer sequentially prints the respective sliding print content based on the respective bitmap format instructions and the print content mode.

Formed is a dither pattern that makes it possible to output an image with excellent dot dispersibility and reduced graininess regardless of controls after quantization processing. To this end, an extended pattern in which multiple divided pixels correspond to each of multiple pixels included in quantization data and one or more of the multiple divided pixels are determined as dot-arrangeable-pixels in which dots can be printed is generated. Thereafter, the thresholds of the dither pattern are set based on the extended pattern in which the dots are arranged to obtain predetermined dispersibility.