Ink Jet Technology Overview

There are three main ink jet technologies used in the addressing market today. These are binary array, drop-on-demand (including piezoelectric and thermal) and continuous (CIJ). While binary array is a CIJ "relative," its features and capabilities warrant a separate, distinct discussion.

Binary Array

Binary array technology features a band, or array, of continuous ink jets. These printheads provide a two-inch print band, with better resolution (256 x 128) than single-nozzle CIJ, at speeds up to 1,000 feet per minute (over 50,000 mailpieces per hour).

A complete printing system can be configured with multiple print bands to provide ultra-high-speed printing, electronic stitching and a print area of up to 191/2 inches by 18 inches. This technology represents the top-of-the-line in digital imaging systems, with higher print quality than single nozzle CIJ, fewer limitations on print speed and broader font and graphics capability including TrueType fonts and downloadable bitmaps. Add to this the ability to print on nearly all substrates including plastics, aqueous coated paper stocks, varnished surfaces, shrink film and clay-coated corrugated without ink drying assistance. A variety of ink types and colors are available for this technology, including MEK-free, organic, solvent-based fluids. These inks were designed to dry quickly (one to two seconds unassisted) and remain smear proof. This technology is ideal for printing text, graphics, logos and barcodes, on consumer-targeted direct marketing literature, catalogs, magazines, business forms, tickets, tags, labels, consumer loyalty cards, etc.

Utilizing a Windows interface with WYSIWYG image layout, job set up and operation are simplified. Printers can be integrated with a variety of production equipment Web presses, bindery and production lines because of the compact design of the printhead, a 20-foot umbilical and the ability to print in any angle (360° rotation) even up means you can produce a digital image on just about any substrate, in just about every in-line application imaginable. For bindery applications, position one printhead upside down underneath the plow station, and add a second printhead printing at a 90° angle on the same plow station.

The I/O capabilities of these printers enable the operator to specify automatic gaps in the production process. This allows for applications including bundling of ZIP Code sorted mailpieces so you can meet U.S. Postal Service requirements for discounts. Additionally, printed items can be separated according to product-specific designation to reduce quantities of pre-printed packaging. The design layout software simplifies your message creation. You can use TrueType scaleable fonts, along with graphics and barcodes (including Postnet, Planet Code, UCC-12, UCC-13, ITF and Datamatrix), to produce whatever image your application demands. These systems typically feature time and date inserts and sequential count. Additionally, you can download information from your network or a CD-ROM. These printers also feature the capability to tie into third-party line controllers, providing the ability to synchronize data in a bindery operation.

Drop-on-Demand Piezoelectric

Drop-on-Demand (DOD) piezoelectric technology utilizes a capillary-fed ink system (the ink is not pressurized). Ink is drawn into the printhead through capillary action and gravity. Piezoelectric transducers "move," either bending or decreasing in length, when a voltage is applied, causing ink to move into the vacated chamber. When the voltage is removed, the piezo returns to its previous position, ejecting the ink from the printhead. Print bands range from half an inch to 21/2 inches, with print resolutions from 90 dpi to 660 dpi. DOD piezoelectric technology provides good print quality for basic addressing functionality, including TrueType fonts, graphic images and barcodes. The most common inks are glycol-based, which perform well on porous and some semi-gloss substrates. Typically, drying assistance is required. Printing speed can be up to 250 feet per minute. These systems also jet UV-curable inks, which provide fast-drying, permanent marks, when cured with a UV lamp. This DOD technology contains no moving parts, so it requires minimal maintenance and provides solid reliability.

Thermal Ink Jet

Thermal ink jet technology employs ink cartridge systems for high print quality (up to 600 by 600 dpi) at a mid-range price. This technology utilizes heat to generate vapor bubbles, ejecting tiny droplets of ink through nozzles. It features small drop sizes, high printhead operating frequency, solid system reliability and highly controlled ink drop placement. Throw distance is limited compared with other technologies. Font and graphics capability includes TrueType fonts and downloadable bitmaps. Print quality is variable and directly correlates to print speed, ranging up to 225 feet per minute at 600 by 300 dpi. Lower print resolution delivers higher · line speed. The water-based inks for this product include black as well as various colors. For many substrates, drying assistance is necessary. This technology was originally developed for desktop printers.

Continuous Ink Jet Single Nozzle

One of the first technologies employed for addressing, CIJ still maintains a strong presence in the industry, although its numbers are dwindling. The technology is very robust and forgiving in just about any standard operating environment. Maximum printing speed of the printer is more than 900 feet per minute. Typical addressing applications run at speeds from 250 feet to nearly 600 feet per minute. Many inks, including color and special purpose, are available. The inks, ranging from MEK- to water-based, provide fast-drying results on most substrates. Opaque inks in bright, vibrant colors produce highly legible marks on dark or even shiny surfaces. CIJ technology can print on nearly all substrates, usually without drying assistance. The print quality is dot matrix, typically five by seven or seven by nine dot characters.

CIJ technology works by applying an electrical charge to a droplet of ink. The drops are then deflected accordingly to create various alphanumeric characters, graphics and barcodes. Continuous ink jet printers provide high-speed, consistent, legible coding, including alphanumeric characters and Postnet barcodes.

Typically, CIJ technology is suited for higher line speeds, where fast-drying marks are required. The character size is small, generally 1/16 inch to half an inch tall. While it is possible to generate characters as tall as half an inch or more, line speed performance is greatly reduced. Single line half inch characters can be printed at speeds over 1,000 feet per minute. Increasing the character height to 1/2 inch or more can reduce the line speed capability to 100 feet per minute or less. For addressing applications, the printer cabinet consists of two printheads that can be positioned independently on the mailpiece. Two, three or four printer cabinets can be configured into a printing system with a single controller. By adding printers, you increase the amount of information you can print without sacrificing line speed.

An ink jet printer is but one tool in the chain of value-added addressing. Along with the printer, a complete system includes the data preparation software, feeder, base, conveyor, tray management, tabber and, possibly, a dryer. These systems are easily tailored to your business to meet the needs of your customers. And as ink jet technology continues to advance, so will your opportunities particularly if you are utilizing ink jet technology.

Scott Liniger has over 14 years of experience in the coding and marking industry. He has held various positions for Videojet Technologies Inc. including product manager, business development manager and market development manager. He currently is a product manager and is a member of UCC/EAN's Global Symbology Committee. For additional information, please contact Videojet Technologies Inc. at 800-843-3610 or visit www.videojet.com.