At 3:15 in the video, if you "listen carefully", the narrator describes two
separate light sources. He says, "Infra-Red
lamps dry the ink in a split second......A
strobe light allows the operator to do spot checks". So there is no infra-red strobe being used here, only a typical white light xenon strobe light in addition to a heat lamp.
Infra-red strobe lamps do exist but good ones with enough power are expensive. (like
THIS one) In theory I think an idea like this could work though. You would want an IR light source of 940nm so that it would be 100% invisible to oncoming cars and pedestrians. The problem would be that you would need a specialized camera with the proper sensor and specific IR-
pass filters on the lens with additional filters to block other parts of the spectrum. In other words you would want to
block almost all visible light wavelengths and have a camera that can
ONLY see the IR wavelengths. Removing the IR-
cut filter from a dash cam will increase the sensitivity to infra-red to some degree but the sensor would still see other visible wavelengths and as
@niko points out, a car's headlights will blow out and overwhelm the camera with too much light for a typical dash cam to handle.