Digital BW, The Print

On 04/14/2003, Paul Roark wrote:

>What MIS has found is that if Eboni black (a very "high load" pigment ink)
>is mixed with dye ink, the viscosity goes way up -- it will not print.  I
>think if there was some Gen 4 Enhanced black (25% dye) in a CIS/CFS before
>the Eboni was added, the system would clog.
>
>So, when switching to Ultra Tone B&W ink with Eboni black, one must use a
>new CIS/CFS cartridge.  In large format printers that have had any dye in
>the black, the system must be flushed.

Paul,

That mixing Eboni-K with some dye ink can likely result in clogs 
seems a very important finding. Do you feel MIS has checked out 
this connection sufficiently so that we can reliably expect large 
viscosty increases whenever these 2 kinds of ink are mixed? For 
instance, if someone using Gen4 enhanced-K in pre-filled carts 
switched over to Eboni in pre-filled carts (just as they would 
have when starting up with MIS FS-K after having used EPS OEM-K 
in their printer), would the extra-viscosity effect be likely to 
occur? 

If the answer is "Yes" (and, hopefully, it isn't), then the 
clog-clearing trick of sticking in EPS OEM dye carts might not work 
with Eboni; it might, indeed, make things worse. (Would running 
purge cycles with cleaning carts, then, be the only way to keep 
Eboni-K and dyes separate?)
 
If you think the switch-over from Gen4 enh-K to Eboni could be 
done without risk of clogging when only pre-filled carts (no CIS/CFS)
are involved, would it be because the amount of Gen4 dye left in 
the path from cart to printhead is just not large enough to trigger 
the super-viscosity effect?

I look forward to getting your take on such questions.

Regards,
John               




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