Patent ID: 6099108
Filing Date: 2000-08-08
Classification: B41J

Abstract:
An ink-jet pen, comprising:a housing;at least one on-board ink reservoir within said housing, the reservoir containing at least one supply of ink of a predetermined chemical formulation;a print head fluidically coupled to said reservoir to receive a flow of ink therefrom;electrical contacts for electrically connecting said print head to a hard copy apparatus;the print head having a plurality of drop generators oriented in an array;at least one drop generator of the array having a plurality of nozzles arrayed about a geometric center point of the drop generator;said at least one drop generator having at least one heating element connected to said electrical contacts;each of said nozzles having an ink entrance port proximate said heating element, said entrance port having an entrance port areal dimension;each of said nozzles having an exit orifice distal from the heating element for emitting ink droplets onto an adjacently positioned print medium, the exit orifice having a predetermined exit orifice areal dimension less than an areal dimension of a pixel to be printed and less than the entrance port areal dimension; andwherein each exit orifice has an exit orifice areal dimension less than or equal to an area calculated in accordance with a formula: the product of the dividend of 1 divided by the number of orifices per drop generator and the areal dimension of a pixel (A.sub.eo .ltoreq.(1/n)*P.sub.a, where A.sub.eo is the exit orifice area, n is the number of orifices per drop generator and P.sub.a is the area of a pixel to be printed) such that the sum of the areal dimensions of the exit orifices in an array of nozzles is less than the areal dimension of a pixel.