| 摘要 |
PURPOSE:To increase a variable magnification rate by providing the 1st projection optical means which varies magnification individually within a specific magnification variation rate range and the 2nd projection optical means which varies magnification beyond the magnification variation range of the 1st projection optical means in cooperation with the 1st projection optical means. CONSTITUTION:A zoom lens 4 as the 1st projection optical system moves to a position 4c during x6 power enlargement while maintaining a specific lens group gap near a normal magnification variation rate range. Therefore, the distance between an original O and a drum 6 varies. For the purpose, an addi tional lens 14 as the 2nd projection optical means is interposed in front of or behind the zoom lens position 4c to hold the original O and drum 6 at con stant distance. Consequently, the zoom lens as the 1st projection optical means has an optional magnification variation rate within the normal range and is combined with the addition lens as the 2nd projection optical means to easily the x6 power magnification rate which is hardly obtained by the 1st projection optical means.
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