US 4,965,593 A · Print quality of dot printers

Abstract

The quality of the images of dot printers such as ink jet printers (20) is improved by spacing the ink jet nozzles (52) of the print head (50) by an amount greater than the pixel spacing of the printing medium (22), and operating the sources in a manner such that adjacent pixels are not printed until the deposited colorant has time to dry. In the traversing direction (39), neighboring pixels are not printed on the same traversing pass. In the advance direction (32), by making the spacing of the ink jet nozzles (52) an integer multiple of the pixel spacing and advancing the print head (50) by a different integer multiple of the pixel spacing, the pixel patterns can be readily printed with high printing volume and with a constant incremental advance of the print head. The present approach is applicable to both color and black-and-white printing, but particular improvement is found for color printing.

Claims9

Dependent claims

A dot printer with the capability to print dots in a pixel array on a printing medium, said pixel array having a first fixed spacing in an advance direction and a second fixed spacing in a traverse direction, comprising:

a printhead having at least two pixel dot sources, the spacing between adjacent pixel dot sources in the direction parallel to the advance direction being equal to the first fixed pixel spacing times a first multiple that is an integer greater than one;
advance control means for moving the printing medium relative to the printhead in the advance direction by the first fixed spacing times a second multiple that is an integer greater than one and selected such that the ratio of the first multiple to the second multiple is an irreducible fraction;
traverse control means for moving the printhead relative to the printing medium in the traverse direction, and
a printing controller that directs the pixel dot sources to operate at pixel row locations that are displaced in the traverse direction from those in the adjacent row by the second fixed spacing times a third multiple that is an integer greater than one.

1 more element

In a printer having a printhead movable in a traverse direction for printing droplets of a colorant onto an array of fixed pixel locations on a printing medium movable in an advance direction, the pixel locations being spaced from each other by a fixed amount in the traverse direction and a fixed amount in the advance direction, said printhead having at least two colorant sources, the spacing between adjacent colorant sources in the advance direction being an integer multiple greater than one of the spacings between fixed pixel locations, the process for depositing droplets of the colorant onto pixels in said array of pixel locations on said printing medium, comprising the steps of:

traversing the printhead across the face of the printing medium in a traverse direction perpendicular to the advance direction;
simultaneously depositing droplets of the colorant onto traversely non-adjacent pixels in the traverse direction by the colorant sources;
advancing the printing medium by a multiple of said fixed amount in the advance direction which multiple of said fixed amount is an amount different from the advance direction spacing of the colorant sources;
and
executing a second traverse movement for depositing droplets of the colorant onto pixels which are non-adjacent in the traverse direction and non-adjacent in the advance direction.

2 more elements

Dependencies are inferred from the claim text.

Print quality of dot printers

Life of this patent

Print quality of dot printers

Life of this patent

Abstract

Claims9