Drop-on-demand (DOD) ink jet printers and continuous ink jet (CIJ) printers are used for printing data on products while they are on the production line. While both types of printers can print at high rates of speed in demanding environments, they are suited to very different applications.
Continuous Ink Jet (CIJ)
|Simple drop-on-demand (DOD) technology developed for more harsh manufacturing environments. Ink supply is connected to print head reservoir whereby droplets are discharged by removing a plunger from the orifice. Inkjet heads are comprised of 7, 16 or 32 orifices.
|Sophisticated technology initially developed for high-speed packaging applications (bottling, etc.). Electronic charge is applied to ink as it is circulating within a continuous loop (ink supply to heads). Charged droplets are attracted to the substrate through a single orifice in the print head. Continuous circulation of the ink causes evaporation of solvents into the working environment.
Dot matrix array produces very legible characters and logos, but not the high-resolution marks that can be produced by CIJ printers. Quality depends on character height and print speed.
Varies (depending on application) from exceptionally high quality to small dots.
|7-dot head: up to 1-1/16”
16-dot head: up to 2-5/8”
32-dot head: up to 5-1/4”
|Character sizes range from .04” to .75”
|DOD prints large dots.
|CIJ prints very small dots.
|DOD prints at very fast speed. Multiple jets fire simultaneously.
|CIJ prints small fonts very fast. There is only one ink nozzle to make all dots, so when font with more dots is used, max print speed is lower.
|DOD has excellent throw distance. Printhead can be placed farther away from the product. The code gets less precise as you print from farther away.
|CIJ has good throw distance. The code gets larger and less precise as you print from farther away.
|DOD printer requires solvents for clean-up.
|CIJ printer requires solvents for clean-up.
|Recovery from Downtime
|DOD printers are modular and designed for easy self-maintenance.
|When CIJ printers go down, they go down hard. Often a service technician must be called in.
|DOD printers are modular. If there is an issue with printhead – you can swap-it-out. There is no umbilical – just a printhead cable, ink lines and a simple pumping system.
|CIJ printers are closed-loop systems. When something goes wrong, the entire printer must be removed for service. Components are thus difficult and expensive to repair or replace – the “umbilical” is the best example and can cost $1,000’s to replace.
|DOD printers are designed to be easy to self-maintain so no service contract is required.
|CIJ printers usually require a monthly service contract because of expected downtime and the complexity of the system.
Continuous Ink Jet (CIJ)
|Ink Drying Time
|DOD has a wide variety of inks for industrial applications with fast dry time.
|CIJ has a wide variety of inks for industrial applications with fast dry time.
|Dye-based vs. Pigmented Ink
|DOD printers can be configured for dye-based or pigmented ink. DOD printers are particularly well-suited for use with pigmented ink.
|CIJ works best with dye-based ink. CIJ units are notorious for running poorly with pigmented ink.
|DOD printers only use ink – make-up fluid not required.
|CIJ printers continuously consume make-up fluid.