Homebrew PCBs

Andrew Thornber wrote:
> Hi,
> 
> I have been lurking on this site for a while now, and thought I might throw
> in a few of my experiences.
> 
> I used to be a printer/proofer engineer and worked on many similar machines
> if not a bit larger than your acerage home machine.
> 
> All of the DOD style printer I worked with were made by the company that
> also manufacture Epson print heads.
> 
> The way that has always worked for me was to get a good look at the nozzles
> and use either a lint free cloth soaked in Isopropyl alcohol and just press
> it gently against the underside of the head.  This almost always worked.  It
> may take a little time but will get there.
> 
> The other way was to use a cotton bud dipped in isopropyl alcohol and clean
> the nozzles.  Then wipe the head with a lint free cloth to get rid of all
> the bits of cotton.
> 
> Running cleaning cycles is about a much use as shouting at it if you have
> some subborn nozzles.  When the head is clamped into the cleaning station
> then it is sucking on all nozzles at the same time.  If one is blocked and
> the others are clear all it will do is suck the ink from the clean nozzle!

With small holes, there is extremely high surface tension, so a large vacuum
can still be exerted even if 90% of the holes are clear. It is more likely that
the ink only flows due to the pressure of the piezo drivers, than any external
applied vacuum.

> Isopropyl alcohol is a standard solvent available from most places.  In the
> UK we used to by it from RS Components but I think if you have a chat with a
> chemist they can get it for you.  It is, if memory serves me correctly, very
> similar chemically to the solvent used in epson inks.  (Which is why we used
> it!)
> 
> Any way, enough of me.  Sorry if I have been teaching any one to 'suck eggs'
> I just thought I might help out a little.