This article aims to provide an overview of the main inkjet printing technologies.
Below is a brief summary:
- The main industrial inkjet technologies
- Operation of a classic two-pump ink-jet system
- Fluid-o-Tech continuous inkjet pumps
Industrial inkjet printers are used for speed marking or printing on commercial items without the need for contact. The marking is used to print simple item numbers to product traceability IDs.
Two main technologies are currently used in industrial inkjet:
1. Drop on Demand - Ink only moved when needed, print mostly on flat surfaces, the print heads eject droplets discontinuously, "on demand". Operation is very simple and the marking very legible. Usually used for macro-characters.
2. CIJ (Continuous Ink Jet) – The ink is continuously circulating through the printhead and around the ink circuit. The ink droplets are electrically charged and are deflected as required by high voltage plates. This technology is characterized by very high speeds (up to 100,000 drops/second) and low operating costs. It is best for small character marking and barcoding on very fast-moving goods on production lines, e.g. cables, tubing and consumer goods.
Continuous ink jet printers include analogue and digital printers. The main features of each are listed below.
Characteristics of "analogue" printers:
- The most common type of machine
- They usually have a single ink jet
- Droplets are deflected on an axis, the product moves to create a 2D shape
- Typically used for date coding, batch marking on production lines
- 1 or 2 pumps per machine
Characteristics of "digital" printers
- Multiple jets per mm, used in 4" (100 mm) wide blocks, often stacked to create 4-colour images
- Deflection is on or off - no variable elements
- Allows very high printing speed
- Up to 36 pumps per machine
Many CIJ systems use gear pumps. Diaphragm pumps are also used. In the past, most systems used two pumps. One for pressure and one for suction (ink return from the printhead). Now most manufacturers have developed single pump systems, with one pressure pump, and a venturi to create suction for the ink return. Alternatively, the diaphragm pump is used as an option.
- Ink is pressured by the Ink Supply Pump and flows from the main Ink bottle to the nozzle parts.
- The nozzle uses ultrasonic vibration to separate a solid pressurized ink stream into small ink droplets as it exits the nozzle orifice.
- The droplets ejected from the nozzle orifice pass through the charge electrode tunnel, and then between the deflection electrodes.
- Each droplet passing through the charged electrode receives a deflection voltage charge where deflection voltage varies between droplets. These charged droplets deflect in a predetermined array pattern depending on the deflection voltage charge.
- After the droplets pass through the deflection electrodes, they continue to travel in their predetermined array pattern out of the printhead and onto the substrate.
- Droplets that are not required for printing are retrieved by the gutter and recycled back into the main ink reservoir for reuse.
Fluid-o-Tech offers a range of continuous inkjet pumps for the paints and inks market capable of maintaining a stable pressure and flow on a variety of dye and pigmented inks and paints, enabling the delivery of an accurate supply on demand.
Our magnetic drive provides a complete leak-free solution and exceptionally long service life.
A wide range of motor options enables us to tailor your product. If required, our pumps can be customized to customers’ requirements and are innovatively designed and developed using the best material selection to ensure protection from chemical attack and long maintenance-free life.
Our team of engineers, with in-depth knowledge of this market, have been designing continuous inkjet pumps for over 70 years and have seen it all. Contact our experts to find out what we can do for you.
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