Hello, I own a 850. It's about 4 years old, still running good. It's far from a perfect printer but If you have the volumen it can be a good investment.
We have a few small latex printers also so we only use the 850 for big runs. we have let our printer up to 4 weeks without use a few times and didn't have a problem with heads or ink going bad.
I really recommend a HP full parts contract with this printer. Parts are really expensive, and they do go bad often. It's better to have it on the budget than having those surprise hits. And I'm not a service contract fan, this is our only printer in the shop that we justify having on a full Parts service contract. All bad thing aside, the printer has paid itself many times over.
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