Browse Prior Art Database

METHOD FOR DUPLEX PRINTING ON CONTINUOUS WEB PAPER

IP.com Disclosure Number: IPCOM000025286D
Original Publication Date: 1984-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 213K

Publishing Venue

Xerox Disclosure Journal

Abstract

In devices for copying, duplicating and printing, an architectural choice is the selection of paper type, either sheet or continuous web fed. Cut sheet has advantages in ease of loading, flexibility for changing paper weights and types, and ability to use formatted paper, i.e., letterhead, prepunched forms. However, the inherent paper path reliability is not as good as that of web-fed paper. Web-fed paper is generally either roll fed or fanfold. Both, however, carry with them a disadvantage of wasting paper in leaders (and/or trailer) when used for short jobs or intermittently. Roll fed paper is also awkward to load, with heavy paper rolls and requires guillotine cutting on the output. Fanfold paper normally uses sprocket feed, and requires bursting and decollation. However, the registration capability provided by the sprockets allows forms printing. For a combination of these and other reasons, cut sheet is currently used on most copiers and duplicators, and short run lithographic printers. Fanfold supplies, which allow asynchronous operation, have become the choice for impact electronic printers. Roll fed paper is used for high volume lithographic presses and for some electronic printers.

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KEROX DISCLOSURE JOURNAL

METHOD FOR DUPLEX PRINTING ON CONTINUOUS WEB PAPER
Edward C. McIrvine

Proposed Classification
U.5. C1. 355/3SH

Int. C1. G03g 15/00

BOTTOM VIEW

NG. 2

FIG: 3

TOP VIEW

20 Volume 9 Number 3 May/June 1984 1

[This page contains 1 picture or other non-text object]

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METHOD FOR DUPLEX PRINTING ON CONTINUOUS WEB PAPER (Con'td)

In devices for copying, duplicating and printing, an architectural choice is the selection of paper type, either sheet or continuous web fed. Cut sheet has advantages in ease of loading, flexibility for changing paper weights and types, and ability to use formatted paper, i.e., letterhead, prepunched forms. However, the inherent paper path reliability is not as good as that of web-fed paper. Web-fed paper is generally either roll fed or fanfold. Both, however, carry with them a disadvantage of wasting paper in leaders (and/or trailer) when used for short jobs or intermittently. Roll fed paper is also awkward to load, with heavy paper rolls and requires guillotine cutting on the output. Fanfold paper normally uses sprocket feed, and requires bursting and decollation. However, the registration capability provided by the sprockets allows forms printing. For a combination of these and other reasons, cut sheet is currently used on most copiers and duplicators, and short run lithographic printers. Fanfold supplies, which allow asynchronous operation, have become the choice for impact electronic printers. Roll fed paper is used for high volume lithographic presses and for some electronic printers.

One area of functional difference between cut sheet and continuous web printers lies in the ability to provide two-sided (duplex) printing. Through well known techniques, such as "automatic duplex", xerographic copiers and duplicators provide indicia on both sides of the copy sheets in a controlled fashion. Most sheet-fed copiers, duplicators, and printers can also provide two-sided output via "manual duplex" wherein the output of pass 1 is inverted and refed from the supply tray to print side 2. Other techniques, such as "immediate duplex" can be used. None of these techniques are directly useful for web-fed paper, however.

High speed web-fed lithographic printers provide duplex capability. They do so through a serial set of printing stations, with a paper inverter such as a tri-roller interposed. The tri-roller layout is used instead of a single roller so as to allow the inverted web to continue in the same direction (or exact direction) after inversion. Paper path direction changes follow the well known angular relations of mirrors in optics (angle of incidence = angle of reflection). Choice of the angles for the roller axes and of the distances between rollers provides the desired direction and lateral position of the outgoing paper web, and the required relative positions of the inverting rolls.

Due to the uniqueness of a laser xerographic printer operating from the electronic data, a number...