Printing

A method according to any preceding claim, wherein a print ribbon is located between the printhead and the substrate such that ink is selectively transferred from the ribbon to the substrate as a result of energisation of the printing elements, the speed of displacement of the ribbon relative to the printhead being less than the speed of displacement of the substrate relative to the printhead such that slip occurs between the ribbon and substrate.

A method according to any preceding claim, wherein the operational characteristics are determined as including a range of operational values, the resolution of the image is selected to ensure that all the rows of pixels in the rendered image can be printed for all of the possible range of operational values, and the selected resolution is maintained regardless of variations over time of the operational values.

A method for generating a printed image by printing or not printing a pixel of the image in each of a matrix of rows and columns of pixel areas, wherein alternate rows of the image are printed on the basis of stored pixel data read from an image memory, and the intervening rows of the image are printed on the basis of calculated pixel data, the calculated pixel data for any one pixel area being calculated as a function of the stored pixel data related to adjacent pixel areas is the two rows adjacent to the row of the said one pixel area.

An apparatus for transferring an image of predetermined length onto a substrate, comprising a printhead incorporating a row of printing elements which may be selectively energised, a memory in which an image may be stored, the image being rendered as a series of rows of pixels, and means for controlling the download of the rendered rows of pixels to the printhead, the control means comprising means for controlling the spacing between printed rows of pixels resulting from relative displacement between the print head and the substrate by controlling the delay between successive energisations of the printing elements, wherein means are provided for selecting the resolution of the rendered image such that the number of rows of pixels in the rendered image is no greater than the magnum number of rows of pixels which can be printed in the image given the operational characteristics of the apparatus.

An apparatus for generating a printed image, comprising a memory for storing pixel data corresponding to rows of pixels in an image to be printed, means for printing out the stored pixel data so as to produce spaced rows of pixels with each row of pixels in the printed image corresponding to a row of the stored pixel data, and means for printing out additional rows of pixel data between each pair of rows of pixel data which correspond to adjacent rows of pixel data in the stored image, the additional rows of pixel data being printed on the basis of the calculation of pixel data from the stored pixel data related to the two adjacent rows of pixels.