FujiXerox VCSEL and resolution
FujiXerox VCSEL and resolution
VCSEL - Vertical Cavity Surface Emitting Laser - is indeed part of the solution - the more important part is the ROS (raster output scanner) - this is a FujiXerox technology -
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While this is part of the 2400 story - it is the LED print head that does the 'marking'
Electro-photography printers and photocopiers form latent images by exposing a charged photoreceptor drum to dots of light. This is a two part two image-writing system and is generally used to form latent images: a raster output scanner (ROS), which uses a laser and rotating polygon mirror, or an LED printhead, which incorporates a light-emitting diode (LED) as a light source.
Since LED printheads do not require a scanning optical system, they offer certain advantages over the conventional and widely deployed ROS system, including smaller dimensions and essentially noise-free operation. However, LED printheads also feature certain disadvantages, including the difficulty of maintaining uniform exposure due to the LED printhead’s many light sources. There are also additional difficulties in maintaining uniform print density.
My read of the technology here is that while they can claim a point of light of 2400 - there is a 1200 interval between these point - so, to me, that means that the smallest space between to 'spots' would be 21 microns - so - 1200 would be the best they could do in one direction.
I am not an engineer, nor cerainly DO NOT have anything bad to say about Xerox here - it is an amzaing feat in engineering !
That being said - just because a light valve can show that I could indeed make a spot of light even as small at a 2400th of an inch - in the Xerox device, even if the tone particle(s) is very small - you must then realize that the process includes a technology for belt fusing/melting adhesion and cooling before stripping (MACS technology) - so, you are tossing some stuff onto a surface, melting that and then fusinging that (heat, roller type of fusing). Besides that - This system has a very tricky problem related to registration - this required Fuji Xerox to develop a digital image registration control technology IReCT (Image Registration Control Technology)
but in almost all cases, the path between a 2400th of inch in a PDF and a spot that is 2400th of an inch on a piece of paper is very complex and hard to really describe - as it involves thousands of technologies - not just one 'makes' this happen. In the end, just like that old "Square Spot" Creo argument, it matters little as to what the laser can do - it is all about how the mark (or spot) of ink, pigment or toner is "applied" to that very rough textured surface - paper - I mean, take a look at a photomicrograh of paper - it is like trying to draw on burlap !
http://chempatec-auhorn.com/images/coatpapersurface_480.jpg