So since I know nothing about this I found:
http://www.youtube.com/watch?v=jtMnWTMRxd4
Does the pad need to be cleaned often? Is there a squeegee that wipes the plate at each pass?
Also how does white ink work? and why can't we put it in printers.
We have mixing white ink at work, but have not used it since I've been there.
Our press is an "offset press" so the plate is inked up, then transfered to a rubber coated blanket cylinder, then transfered to the paper. Kind of seems like what you are doing, your pad is our blanket. We wash the paper lint off the blankets at the end of the run each day.
This isn't ours, but it is the same brand:
http://www.youtube.com/watch?v=cMYb9zhmq-Q
I used to manage an offset print shop, and I serviced offset presses for a while. The two processes seem similar, but they're very different from the standpoint of how much ink is applied.
Pad printing starts with images that are physically etched into the metal plate. These wells hold quite a lot of ink, comparatively*, which is smeared on, and the excess is literally scraped away with a steel blade (some use a special pad to wipe away the excess). The ink left in the wells is then transferred via the pad to the object. There may be other pad printing techniques; this is what I am familiar with.
In offset printing, the ink is deposited on the rubber blanket through a process that takes advantage of the fact that oil and water don't mix. The image on the plate is water-resistant, so it is ink-receptive; the rest of the plate is water-receptive, so the ink won't stick. (That's why you apply both ink and water to the plate.) The blanket is used to transfer the ink from the plate to the paper because the paper would quickly destroy the plate if they came into direct contact. The layer of ink delivered to the paper is microscopic compared to the amount stored in the physically-etched image on a pad printer plate, and so offset printers simply cannot apply enough ink to be opaque.
Most inks used in offset printing are semi-translucent as it is. Four-color process printing uses yellow, cyan and magenta inks as subtractive primaries to produce full color, and black is added because the colored inks are not dense enough to create convincing dark tones. White ink in offset printing is used mostly to adjust the color of inks for custom spot matches, as opposed to applying a white image on a dark background.
*Even then, for a good solid white or light color, it may require multiple hits.
