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Start Stop Technique for Ink Jet Systems

IP.com Disclosure Number: IPCOM000088560D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Mitchell, JW: AUTHOR [+2]

Abstract

In ink jet systems, particularly when the ink is made of a high concentration of particulate materials (such as magnetic ink or carbon black inks), aim changes result when carrying out start-stop sequences without protecting the nozzle exit. The main reason for this problem is that the fluid tends to leave solid residues upon evaporation or oxidation, and these residues build up with time, thereby affecting directionality of the stream.

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Start Stop Technique for Ink Jet Systems

In ink jet systems, particularly when the ink is made of a high concentration of particulate materials (such as magnetic ink or carbon black inks), aim changes result when carrying out start-stop sequences without protecting the nozzle exit. The main reason for this problem is that the fluid tends to leave solid residues upon evaporation or oxidation, and these residues build up with time, thereby affecting directionality of the stream.

This problem may be alleviated by capping the nozzle in pure ink every time the jet is stopped. Then upon start-up, the outside of the nozzle is rinsed clean with a suitable flush fluid to prevent solid buildup on the nozzle orifice.

The system described above works fairly well as far as aim constancy is concerned during a few start-stop cycles. However, microscopic deposits, which are termed "beads," form on the nozzle periphery. These "beads," or shiny microparticles, once they form, keep growing with time because they are insoluble in the fluid.

The prevention of the formation of these "beads" is a crucial problem in solving the start-stop directionality changes in a magnetic ink jet system.

This problem is solved by the use of a gas stream in conjunction with a flush fluid. There must be accurate timing between the starting of the ink jet stream and injection of the flush fluid, including the use of a gas stream impinging on the nozzle in synchronization with the flush fluid application...