Patent ID: 8764161

Claim:
A method of continuous inkjet printing comprising: A) providing a main fluid supply of a continuous inkjet printer with a printing fluid comprising water, a soluble or dispersed polymeric component, and less than a total of 10 wt % of low-volatile water soluble humectant having a boiling point of greater than 170C; B) delivering the printing fluid from the main fluid supply to a printhead and ejecting a continuous stream of the printing fluid from the printhead which continuous stream is broken into spaced droplets; C) in response to electrical signals received from a control mechanism, controlling the spaced droplets to select between printing droplets for marking a substrate and nonprinting droplets that are collected and returned to the main fluid supply; D) stopping delivery of the printing fluid to the printhead upon completion of a printing procedure; E) providing a maintenance fluid supply with a maintenance fluid comprising water and at least 5 wt % low-volatile water soluble humectant having a boiling point of greater than 170C, wherein the concentration of low-volatile water soluble humectant in the maintenance fluid is greater than that in the printing fluid; and F) delivering the maintenance fluid from the maintenance fluid supply to the printhead after use of the printing fluid in the printhead and ejecting the maintenance fluid from the printhead to purge the printing fluid from the printhead.