| 摘要 |
A vacuum take-off conveyor is used to transfer a printed sheet from a delivery conveyor to a sheet stacking apparatus. The vacuum conveyor has a vacuum chamber structure with an inner chamber. A vacuum source is connected to the chamber structure, near a first end thereof, and operates to create a pressure differential between the chamber and the surrounding atmosphere. The chamber structure is provided with longitudinal slots in a bottom wall to provide air communication from the atmosphere into the chamber. An endless foraminous belt is received onto the chamber structure to form a continuous loop from the first end to a second end thereof, and is rotated by a drive pulley. A damper, such as an adjustable damper plate, is situated within the chamber so as to produce a high vacuum region near the vacuum source between the damper plate and the first end of the chamber structure, and a low vacuum region between the damper plate and the chamber structure second end. Additionally, side walls of the chamber structure have a plurality of orifices therethrough, which apertures can be selectively closed or opened to affect the relative pressure differential between the high and low vacuum regions and the surrounding atmosphere.
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