Abstract: A method for printing an object using a color image printer is provided. The printer applies colorant dots having a flat shape. The object has an apparent surface with a locally varying color for representing a color image on the surface. The printer comprises a white colorant, that is applied as a background underneath a surface colorant for begetting a local color of the apparent surface. The invented method comprises the steps of: generating two-dimensional image data for composing the object in slices; determining a local surface orientation of the apparent surface of the object; and applying colorant material in accordance with the two-dimensional image data, wherein, in dependence on the local surface orientation, white colorant dots are deposited between other colorant dots to compensate a color effect of an orientation of a surface colorant dot relative to the local surface orientation.

Abstract: A method for printing an object using a color image printer is provided. The printer applies colorant dots having a flat shape. The object has an apparent surface with a locally varying color for representing a color image on the surface. The printer comprises a white colorant, that is applied as a background underneath a surface colorant for begetting a local color of the apparent surface. The invented method comprises the steps of: generating two-dimensional image data for composing the object in slices; determining a local surface orientation of the apparent surface of the object; and applying colorant material in accordance with the two-dimensional image data, wherein, in dependence on the local surface orientation, white colorant dots are deposited between other colorant dots to compensate a color effect of an orientation of a surface colorant dot relative to the local surface orientation.

Abstract: A method for generating a halftone image includes the steps of, for each input pixel, adding a previously determined error term to the input pixel value to obtain a modified input pixel value; determining an error diffusion threshold level based on the input pixel value; applying a quantization operation to the modified input pixel value using the determined error diffusion threshold level for obtaining an output pixel value; and determining an error contribution. The error diffusion threshold level depends on a result of a comparison operation performed between the input pixel value and a threshold value selected from a set of threshold values, the selection of the threshold value being based on the position of the input pixel in the input image.

Abstract: The structural base unit of the machine is made of a one-piece shaped beam (40) which extends along a first direction (Y) with a first portion (41) which, due to its own stiffness, supports and guides the carriage (12) carrying the writing head (11) along its translational motion in the first direction (Y), and with second and third portions (45) which defines supporting surfaces for the drum (20) driving the printing medium in a second direction (X) perpendicular to the first direction (Y). Guiding of the carriage (12) is ensured by rails (43, 44) formed integral with the beam or attached to it, and a slot (50) cut in the shaped beam (40) along the action area of the writing head for providing a passage for the printing medium and its engagement with the drum (20).