Continuous ink-jet printer and method of operation

A continuous ink-jet printer comprising

• means for providing a stream of droplets from a nozzle of a continuous ink-jet printhead;
• means for applying a charge to individual ones of the droplets;
• a pair of deflection electrodes for deflecting individual charged droplets from the stream of droplets to a required print position on a substrate moving past the printhead, said deflection electrodes being disposed at a preselected angle relative to the path of movement of said substrate;
• means for determining, in accordance with the deflection electrode angle, for each of a series of droplets to be printed on the substrate to form an image, the value of the charge to be applied to the droplet and including one or more memories containing values representative of the vector position of each droplet of each printable character, whereby the value of the charge to be applied to each droplet to be printed is determined;
• means for setting a predetermined substrate speed into said printer;
• means for sensing the actual movement of the substrate;
• means for determining the speed of movement of the print substrate relative to the printhead;
• and
• means for correcting the values of the charges to be applied to the droplets in the stream immediately prior to the charging signals being fed to the printhead and after they are read from the memory or memories and adjusting the number of uncharged droplets between printable droplets in accordance with the determined speed of the substrate.

A continuous ink-jet printer comprising

• a continuous ink-jet printhead having a nozzle for providing a stream of droplets;
• a drop charger to apply a charge to individual droplets
• a pair of deflection electrodes for deflecting individual charged droplets from the stream of droplets to a required print position on a substrate moving past the printhead,
• said deflection electrodes being disposed at a non-perpendicular angle relative to the path of movement of said substrate,
• a drop charger controller connected to said drop charger to have said drop charger apply a charge to selected printable droplets and no charge to other preselected droplets to provide uncharged droplets,
• a speed detector to detect the speed of substrate relative to the printhead,
• said speed detector connected to said drop charger controller,
• said drop charge controller determining, in accordance with the deflection electrode angle, for each of a series of droplets to be printed on the substrate, the value of the charge to be applied to the droplet, and
• said drop charge controller adjusting the number of uncharged droplets between printable droplets in accordance with the determined speed of the substrate.