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Technology

How industrial inkjet works.

Every inkjet mark is built from individual droplets. Here is how continuous inkjet and drop-on-demand printers form, direct and place them.

From drop to mark

From a Single Drop to a Production Line.

Industrial inkjet printing builds every mark from individual droplets of ink. Each droplet has to be formed, directed and placed at the right moment — while the product keeps moving.

  1. DropletA single droplet, formed at the nozzle.

  2. StreamDroplets at even spacing, directed in flight.

  3. MatrixDroplets placed on a grid to form a character.

  4. CodeCharacters in sequence: a readable mark on the product.

How it works

Inside the printhead.

Continuous inkjet. A pump feeds pressurised ink from the tank to the printhead. A piezo modulator breaks the jet into uniform droplets. Droplets pass a charge electrode; charged droplets are bent by the deflection plates onto the product, uncharged droplets fall into the gutter and return to the tank. INK SYSTEM PRINTHEAD Ink tank Pump pressurised ink + HV0 V unused ink returns to the tank travel Piezo modulator Charge electrode Deflection plates Gutter Product FRONT VIEW 12345 Valve-based drop-on-demand, as used in large-character printers. A pump feeds ink to a manifold behind a row of nozzles. Each nozzle has its own valve, which opens only when the print signal calls for a droplet in that row, so the character is built column by column as the product passes. INK SYSTEM PRINTHEAD Ink tank Pump travel Ink manifold Valve per nozzle Nozzle plate Valve opens → one droplet Product FRONT VIEW 12345
Continuous inkjet — as in the DV-C500. Simplified, not to scale.Valve-based drop-on-demand — as in the DV-L500 large-character printer. Simplified, not to scale.
  1. 1

    Ink supply

    A pump keeps ink under pressure and feeds it to the printhead.

    A pump feeds ink to a manifold behind the nozzles.

  2. 2

    Droplet generation

    A piezo modulator breaks the jet into a continuous stream of uniform droplets.

    Each nozzle has its own valve; a droplet forms only when it opens.

  3. 3

    Droplet control

    Droplets are charged; the deflection plates bend each one to its height. Uncharged drops return via the gutter.

    The print signal decides which valves open, column by column.

  4. 4

    Deposition

    Charged droplets fly to the product without touching it.

    Droplets cross a short gap from the nozzle plate to the product.

  5. 5

    Mark

    Columns of dots build characters as the product moves past.

    Large dot-matrix characters build up as the product moves past.

Precision

What precision means in inkjet.

  1. Form

    A droplet of consistent size and shape, every time one is formed.

  2. Direct

    Placed where the character needs it, at the speed of the line.

  3. Repeat

    The same result on the first product of a shift and the last.

Glossary

Terms you’ll meet.

Continuous inkjet (CIJ)
A continuous stream of droplets is generated; selected droplets are deflected onto the product and the rest are recirculated.
Drop-on-demand (DOD)
Droplets are ejected only when the print signal requires them.
Large-character printer
A DOD printer with a column of valve-controlled nozzles, used for big text, codes and logos.
Character height
The height of the printed characters, set by the number of dots and their spacing.
Throw distance
The gap between the printhead and the product surface.
Charge electrode
In CIJ, the electrode that places a controlled charge on each droplet as it forms.
Deflection plates
In CIJ, plates at high voltage that bend the path of charged droplets.
Gutter
In CIJ, the catcher that collects unused droplets and returns them to the ink system.
Dot matrix
A grid of droplet positions from which characters are built.
Substrate
The surface being printed on.

Let’s Talk About Your Production Line.

Tell us what you need to mark, what you’re marking on and how your line runs — or write to info@davincitechinc.com.

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