Homebrew PCBs

Stefan Trethan wrote:

   Had a thought that we probably need a very high value resistor between the 
corona wire and the metal surface.  While the voltage is reasonably high, the 
capacity of a sheet of paper would be almost nil, it's almost purely a static 
charge with almost no current.  I can just see a sheet of metal hitting the drum 
and not only the contact line transferring but 1/4" up the drum discharging and 
a ton of toner falling off.  May still work ok really since the drum coating has 
to be high resistance to hold the image.  But it'd cost almost nothing to use a 
good resistor and not depend solely on the drum coating, and it may be necessary 
for reliable operation.  Maybe even megaohms since the voltage is high and the 
current should be very low.  Corona wire supply is probably very light to begin 
with, but I would still bet it is many times what would possibly come off of the 
sheet of paper after passing it.

Alan