| 摘要 |
PROBLEM TO BE SOLVED: To improve a hold down-device for eliminating influence of cockles in a printing zone. SOLUTION: A hold-down device for a medium is provided for a medium on a platen 11. The hold-down device comprises a first cockle controlling means for controlling expansion of a medium 6 into a wave-like shape defined by a plurality of bubbles in a medium outputting zone 9 on the downstream side of a printing zone 8, with a frequency substantially matching the ridge frequency on the ridged surface of a supporting platen 11. Moreover, a second cockle controlling means may be included for controlling expansion of the medium 8 in the printing zone 8 into at least two parallel wave-like shapes defined by a plurality of bubbles, with a downward bubble of the wave disposed adjacently with an upward bubble in the medium 6 moving direction or disposed alternately without any bubble disposed adjacently. Influence of cockles can be eliminated preferably without pulling the medium from the printing zone to the downstream side so that generation of vertical banding can be prevented.
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