The Basics of Inkjet Printing Explained

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Inkjet printing is essentially the same process whether it’s used for standard printing at home or in complex applications in industrial applications. The biggest difference is in the industrial ink types, the printheads, and the programming for industrial applications. For instance, you can’t print on a curved object in a standard personal home printer, but there are special printheads for industrial use.

To start with, inkjet printing happens via uniform droplets of printed on a substrate. Some of the reasons it’s so popular include:

  • Low-cost printing
  • Non-contact printing
  • Low material waste that conserves resources
  • A Maskless process
  • Additive patterning

The two categories in which this process is used are known as continuous inkjet (CIJ) and drop-on-demand (DOD) printers.

  • CIJ – Continuous inkjet printers eject ink at high pressure and is projected into uniform droplets through electromechanical components. As the droplets are being charged by these components they are also being directed to the proper placement.
  • DOD – Drop-on-demand printers use piezoelectric technology to drop uniform droplets of ink on the substrate. It starts with voltage being applied to a channel, then the piezoelectric effect takes place. From there, the channel becomes enlarged and is filled with industrial ink. The voltage is applied to the next channel, which also enlarges at the same time the other channel shrinks as it drops the ink.

Another type of DOD printing is thermal printing where heat produces a bubble that forces the ink out of the jet and forms a droplet.

How droplets create images

When the ink is drop onto a substrate, continuous inkjet printers deflect the droplets so they land in the programmed areas of the substrate. DOD printers move the substrate around to create the image as droplets are ejected onto the substrate on demand as needed.

Factors that influence print quality

The three factors that affect the quality of the printing include the porosity of a substrate (how wet it can get), the drop volume, and the drop speed. The main thing that affects quality is in the kind of printhead used for printing. The piezo printhead are known to provide the best quality image printing.

Types of printheads

 

  • Satellite printheads shot out droplets with ‘tails’, which are split into smaller droplets then ejected onto a substrate.
  • Angle deviation printheads can change the direction of the droplets
  • Crosstalk printheads influence the channels via common walks affecting the speed and volume of the droplets, which influences print quality

Industrial ink factors

Things that affect image quality in inkjet printing include:

  • Viscosity, which affects the speed at which the droplets are ejected
  • Velocity, which influences the density and filling the printhead

Industrial ink applications

Industrial inkjet printers are used across multiple industries and for several applications.

  • Personalization
  • Biological and pharmaceutical applications
  • Image printing
  • Marking and coding
  • Food and grocery
  • Health and beauty

There are even special curving mechanisms used to improve the adhesive effect on various substrates for inkjet printing.

The uses for inkjet printing and industrial inks are virtually unlimited across industries. CIJ and DOD are two of the most popular inks&printing technologies used because they are efficient, effective, low-cost, and low-maintenance.