Hi fuse F4-F5 ARE FOR protecting coil of contactor k1 k2 ,etc and limit switch
in the paper cutter.
Look carefully if there some loose cable, or broken contact from limit switch or for contactor, and doing short circuit, and that way porducing blown fuses. of course the main switch, can be in short circuit too, since they have contacts inside, and can be broken producing the short circuit for bown the FUse f4
Let me know, sincerely
Blessing