'Ink' jet droplet measurement

During the development of the first ink jet printers the printed droplet was measured when the droplet landed on a sheet of paper or test material. The next step was creating a droplet measuring device which was capable to measure the droplet after it was leaving the print head.
JAIMS_image_small_sequence Important to know was the volume and speed of the droplet,but also the way how a droplet is created including the satellites and the path the droplet follows after it's left the print head.

This ink jet technology is not only used for dosing ink but also for dosing other fluids. Nowadays they are also used for production of solar cells, displays, chips and in pharmaceutical industry etcetera.

JAIMS_Inkjet_Sequence For further improvement of 'ink' jet printers, it is still important to perform very accurate and reliable measurements of the droplet and its behavior in an air or gas environment.
Fore this a good sharp image of the droplet is necessary.
The measurement configuration is based on a flashed backlight and a camera with a suitable lens. It is very simple to create an image of a droplet but to create a good and sharp image the backlight, the optics and the flash has to be optimized.
In a lot of commercially available 'ink' jet equipment the quality of the created image is (very) bad.

Commercially available and by JAIMS improved droplet image quality

The first image on the left is a drop (sub) image of a commercially available 'ink' jet printer for the professional market.
The second image is a drop (sub) image of a professional printer used for printing displays.
The third (sub) image is the result of the by JAIMS improved vision setup of the same professional printer.
Comm_Available_Droplet_Line_Profile_subim PDP_Droplet_Line_Profile_subim JAIMS_ImpPDP_Droplet_Line_Profile_subim JAIMS_CAP_Droplet_Line_Profile JAIMS_PDP_Droplet_Line_Profile JAIMS_ImpPDP_Droplet_Line_Profile Comm_Available_Edge_Strength_Profile PDP_Edge_Strength_Profile JAIMS_PDP_Droplet_Edge_Strength
The (sub)images show the intensity profile of these droplets measured over the horizontal green line.
The graphs show the 'edge strengths' (derivative of edge intensity) measured over the same image line.

The measured 'edge strengths'
Commercially available printer: left 39; right 42.
Professional display printer: left 82; right 83.
By JAIMS improved professional display printer: left 96; right 101.

The left image shows the droplets of the professional display printer and the centre image the results of the by JAIMS improved droplet measurement setup. The right image displays a droplet at a larger magnification.

JAIMS_PDP_Droplet_Image JAIMS_ImpPDP_Droplet_Image JAIMS_Zoom image

Only when a good and sharp image is created a reliable and accurate measurement can be performed.
Though the results of these measurements are not shown in this overview.