A Chip Off the Old Block

Last night I completed work refurbishing the last of the six ink drums for my Risograph ME 9450U duplicator following a marathon afternoon session on Sunday essentially rebuilding nearly all the other drums to re-check and replace the light absorbing strips on each. The aftermarket versions proved to be incompatible with this particular machine. The ones used on drums for the EZ391U machine worked fine though.

These light absorbing strips are used by the machine to detect when a master (stencil) is present on a drum. In the case of the aftermarket parts, they don’t absorb enough light for this to work as expected which is kind of a bummer. One solution was to use a black Sharpie and draw all over them to increase their opaqueness, but it felt very tacky and potentially unpredictable. The Riso on a good day is unpredictable enough thank you very much. And so I luckily was able to call on an old friend who helped hook me up with real replacement parts.

After all this work to tear apart, deep clean, and rebuild these drums, I was reminded of where this all started — which was repairing one of the EZ drums which triggered an ink overflow error from the PCB sensors inside the drum. The two wires sticking out from the PCB in the photo above are used to detect ink levels through a low voltage electrical signal.

And now, I hope to not have to touch the inside of a Riso drum again for a long, long time.