Browse Prior Art Database

Multiple Vacuum Duplexer Roll

IP.com Disclosure Number: IPCOM000045319D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Karol, KN: AUTHOR

Abstract

A multiple vacuum port is illustrated in the figure which eliminates the need for a high-capacity, high-vacuum blower to vacuum transfer or duplex paper at high handling rates.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 94% of the total text.

Page 1 of 2

Multiple Vacuum Duplexer Roll

A multiple vacuum port is illustrated in the figure which eliminates the need for a high-capacity, high-vacuum blower to vacuum transfer or duplex paper at high handling rates.

Previous research has documented the substantial difference in vacuum pressure required to hold a sheet of cut paper on a rotating drum, as opposed to the pressure required to retain the paper on a flat belt. Thus, it has been found that about 20 inches of water vacuum is a boundary condition for having sheets remain upon a rotating drum operating at speeds of handling up to 2500 rpm. The stipulated blower requirement is 35 inches of water at 35.3 cfm for such operation. On the other hand, cut paper usually requires only one-half to one and one-half inches of water for retention upon a flat belt.

With respect to retention of cut sheets upon a rotating drum, the most critical section of the paper is the leading edge due to its cantilever configuration with respect to the round surface of the drum. The vacuum drum illustrated in the figure alleviates the paper-retention problem by providing a small high vacuum manifold 15 for the leading edge (the trailing edge can also be handled by a similar manifold). This enables the provision of the required high vacuum within a small volume supplied at a much lower flow rate by a smaller pump or blower. The larger manifold area 16 can be provided at a lower manifold pressure without sacrificing retention of the sheet surfa...