The printhead is the heart of any inkjet printer, and the design and construction of the printheads determine a number of key properties including spatial resolution, print speed and ink deposit. Fujifilm industrial printheads are designed for a range of applications, and versions are available that are compatible with most common ink types including UV, water based, hybrid and oil based systems.
Once the printhead has been integrated into a suitable system, it receives ink at the correct temperature and flow rate from the ink delivery system.
The printhead is also fed with image data that tells the head when to fire a droplet, and a waveform that tells it how to fire the droplet. Finally, the environment including temperature and pressure is regulated to ensure optimum performance.
The fluid characteristics of the ink itself are carefully matched to the printhead in order to optimize drop formation. These fluid characteristics are what makes the droplet round, and keep it moving in the right direction without breaking up, ensuring that satellite or mist formation is minimized.
The ability to match printheads and inks for a particular application and to tune waveforms to optimize jetting performance is a key Fujifilm technology, and this is illustrated below. This, together with the ability to tune the fluid characteristics of the inks mean that Fujifilm is able to optimize jetting performance and ensure maximum performance and reliability.
A waveform is a series of electronic signals that is used to fire an ink droplet from a drop-on-demand piezo printhead. It determines everything from the size and velocity of an inkjet droplet to the speed of printing and is a major contributor to overall system reliability.
This diagram shows a series of waveforms that would be used to produce droplets in a greyscale printhead. Each of the larger pulses starts to eject a droplet that combine on the nozzle plate to form a large droplet. A 'cancel pulse' can be included to break the droplet off cleanly, minimising satellite and mist formation.
Waveforms have to be precisely tuned to the dynamic response between the ink and the printhead itself, and Fujifilm is able to create highly optimized waveforms due to its in depth knowledge of printheads and inks.
A typical three pulse waveform in a greyscale printhead
Typical multi-pulse waveforms in a greyscale printhead
Fujifilm Dimatix produce a range of inkjet printheads for industrial and package printing applications as well as established wide format graphic printing. These class leading printheads employ a range of proprietary Fujifilm technologies and combine these properties to produce some of the best and most reliable printheads available today. These technologies include:
- Redijet technology incorporating ink recirculation past the nozzle for quick start up, long standby times and reliable operation
- Fujifilm non-wetting nozzle plate coating, reducing contamination and helping to maximize up time with high duty cycles
- Silicon MEMS architecture allowing 'printhead on a chip' construction, maximizing nozzle density and minimizing drop size
- Versadrop variable drop management, allowing greyscale printing to enhance visual print quality
- High frequency operation providing high speed printing
- Compatibility with most inkjet ink technologies including water based, UV, hybrid, oil based ceramic and the associated maintenance fluids
- Unique Fujifilm piezo ceramic with superior piezoelectric performance