CONTINUOUS INKJET PRINTER
Technology Overview
The continuous ink jet (CIJ) method is used commercially for marking and coding of products and packages. In CIJ technology, a high-pressure pump directs liquid ink from a reservoir through a gun body and a microscopic nozzle, creating a continuous stream of ink droplets. A piezoelectric crystal creates an acoustic wave as it vibrates within the gun body and causes the stream of liquid to break into droplets at regular intervals: 64,000 to 165,000 droplets per second may be achieved. The ink droplets are subjected to an electrostatic field created by a charging electrode as they form; the field varies according to the degree of drop deflection desired. This results in a controlled, variable electrostatic charge on each droplet. Charged droplets are separated by one or more uncharged “guard droplets” to minimize electrostatic repulsion between neighboring droplets.
The charged droplets pass through an electrostatic field and are directed (deflected) by electrostatic deflection plates to print on the substrate, or allowed to continue on un-deflected to a collection gutter for re-use. The more highly charged droplets are deflected to a greater degree. Only a small fraction of the droplets is used to print, the majority being recycled.
The major advantages are the very high velocity (~50 m/s) of the ink droplets, which allows for a relatively long distance between print head and substrate, and the very high drop ejection frequency, allowing for very high-speed printing. Another advantage is freedom from nozzle clogging as the jet is always in use, therefore allowing solvents such as ketones and alcohols to be employed, giving the ink the ability to “bite” into the substrate and dry quickly.
CIJ Key Benefits
- A most affordable and reliable method to print real-time lot/date codes.
- Print on virtually any surface or substrate.
- High-Speed Printing in any direction or angle.
- Non-contact printing, print distance is ½” (12mm) plus.
- Variety of ink types and colors for immediate dry times on porous and non-porous products.
