Continuous inkjet (CIJ) printers

Continuous inkjet printers discharge ink to print directly on a target. This is a non-contact method which can print on any type of target without blurring, printing flaws or damaging the target.
The compact head size and the ability to print in any direction ensure easy installation in a wide range of applications from conveyors to packaging machines.

KEYENCE Product Information

Continuous Inkjet Printer
MK-G Series

MK-G Series is the world's first self-troubleshooting continuous inkjet printer that completely eliminates the guesswork of inkjet maintenace and can be operated without any specialized product knowledge or skills.

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Operating Principles of Continuous Inkjet Printers

Printing principle
  • Pressurized ink is supplied to the print head from the controller.
  • Ink is fed to the nozzle which has the piezoelectric oscillator and discharge hole.
  • The ink is discharged while being oscillated by the piezoelectric oscillator, and it is simultaneously given a negative electrostatic charge. The ink is formed into an ink column, but when saturated with the negative charge, the ink becomes particles, and those particles separate from the ink column.
  • The electrostatic detection sensor monitors the ink particles to ensure they receive the appropriate electrostatic charge to prevent malfunction.
  • The ink particles that discharge from the nozzle pass between two deflecting electrodes where an electrical field is generated by a voltage of around 7000 V. At this time, a bending force acts on the ink particles according to their electrostatic charge to change the direction they travel. Synchronously, the target or print head is moved perpendicular to the ink particle travel direction to print the desired content.
  • Ink not used for printing is collected in a pipe called the gutter and reused.

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Internal Structure of Continuous Inkjet Printers

This section explains the internal path and ink circulation principle of continuous inkjet printers.



Circulation principle

  • 1Main tank

    Stores the ink used in printing. Ink recovered from the gutter is also returned here.

  • 2Pump

    Pressurizes and feeds the ink from the main tank to the print head.

  • 3Pressure reducing valve

    Adjusts the ink pressure.

  • 4Piezoelectric element

    Oscillates the ink stream discharged from the nozzle to separate into ink particles.

  • 5Nozzle

    Discharges the ink.

  • 6Electrostatic electrode plates

    Applies a negative electric charge to the ink particles created from the ink stream.

  • 7Electrostatic sensor

    Monitors whether the ink particles have the proper electrostatic charge in them.

  • 8Deflecting electrode plates

    Generates a magnetic field between the electrode plates to deflect ink particles according to their charge. This directs ink particles onto the print target.

  • 9Gutter

    Collects the ink particles that are not used in printing.

  • 10Pump

    Retrieves the ink particles from the gutter and feeds them to the main tank.

  • 1Main tank

    Repeats the ink circulation.

Solvent tank
Supplies solvent to control viscosity when the ink in the main tank becomes too thick.
Ink tank
Supplies ink to the main tank when it is empty or when the ink is too thin.

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Continuous Inkjet Printer Applications

Continuous inkjet printers

This method is commonly used with industrial-use printers.
Continuous inkjet printers are capable of printing on a wide variety of targets such as metals, resins, and glasses. In addition to being able to print on materials such as paper and cardboard, the quick-drying ink enables printing on materials that do not absorb ink well. Continuous inkjet printers are used in a wide range of industries such as food, medicine, cosmetics, electronics, semiconductor, automotive, and metals.

Food, medicine, and cosmetics

For food safety, it is necessary to accurately print manufacturing dates and best before dates.
To prevent printing mistakes and non-printed sections, there has been an increase in the installation of inspection systems using image sensors and the implementation of similar countermeasures.

  • Pet Bottle

    Pet Bottle
  • Packing film

    Packing film
  • Resin bottle

    Resin bottle
  • Glass


Electrical and electronic components

The non-contact method is optimal because the parts are easily damaged by contact. Also, continuous types can print lot numbers, which helpful in the consumer electronics industry in order to track a component’s manufacturing history.

  • LED

  • Dry battery

    Dry battery
  • Circuit board

    Circuit board
  • Capacitor


Automotive, metal, etc.

The need for traceability is well recognized in the automotive industry. Due to recent progress in the common use of components, this printing method is seeing increased use in applications where the printing of identification numbers is necessary to prevent assembly errors.

  • Aluminum material

    Aluminum material
  • Wood

  • Metal component

    Metal component
  • Cable


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