The present invention relates to a metal cathode sheet assembly for use in the electrolytic recovery of pure metals, especially copper, in an electrolysis tank. According to the stored programs, the at least one processor transports sample containers through a conveying path along which there are arranged at least one first module for testing of samples and at least one second module for processing of samples which have been tested by the at least one first module. The second controller controls ejection of the ink drops from a second inkjet head for ejecting a second ink for which coverage over a recording surface of the recording medium is required, in a manner that a number of ink dots formed in the main scanning direction is small, and that the number of ink drops ejected for each of the ink dots is great.