Hitachi continuous inkjet printer seldom goes wrong, so when there is something wrong with it, we normally just replace a whole part instead of trying to repair it.
The most often repairable Hitachi CIJ printer part is the pump. When it leaks, we usually replace a new pump, but we could try a cost-wise way to repair it first, by replacing the pump membrane.
Please feel free to contact if you have further question.
L&S CIJ Codification Parts 