Hey a little ranting can be good for everybody, keeps all of us on our toes.
I understand your frustration, it must be similar to ours and being unable to recreate it in a controlled setting.
I HIGHLY recommend keeping a printer log for those having any kind of issues.
For mechanical printing issues, log the date and time.
It can be very helpful to narrow down the cause, or at least eliminate some options.
I.e. if you find you have printer lock ups or corrupted prints, and it happens every Friday at 2 o'clock, it is less likely to be your printer and more likely something that happens on Friday at 2.
Chilled, If you would, log your cleaning and cleaning solutions used, and any proceedure that you are using that is not in the manual.
If you have the means, log your room temp and humidity from time to time.