Casio UP-250 Technical Manual page 67

CAUTION:
Never turn the ribbon cassette's feed knob in the opposite direction of the arrow
marked on the cassette; otherwise the ribbon cassette may be damaged.
5. Insert the ribbon in the position shown in the illustration below and push the ribbon cassette
until it clicks.
Note:
Make sure that the ribbon is installed between the print head and the platen without wrinkles or
creases.
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