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Handling Paper Overview Paper Path Paper Feed Registration Paper Transport Duplexing Misfeed Detection Handling Originals Handling Finished Copies/Prints Overview For most machines, paper handling can be broken into six main procedures: feed, registration, transport, duplexing, misfeed detection and finishing. Originals are handled in a similar, though separate, fashion. Paper handling begins at the paper source--this could be a paper tray, cassette, roll, or a single, hand-fed sheet in the by-pass tray. The paper feed process ensures that the paper is positioned and ready for use. It also feeds the paper into the main unit, and separates sheets of paper so that only one sheet is fed at a time. Registration ensures that each sheet is positioned properly for printing. Registration typically addresses two issues: timing and skew. For timing, it synchronizes the image on the photoconductor with the paper. It ensures that the leading edge of the paper matches the leading edge of the developed image. Meanwhile, skew control ensures that the paper is lined up straight. It compensates for slight rotations to the paper during paper feed. 1 April 2001 Page 5 Handling Paper Paper Path Paper transport is merely moving the paper. Paper is usually transported from paper feed to registration, from paper separation to fusing, and from fusing to the finisher or output tray. Not all machines are capable of double-sided printing; however, those that are must have some type of duplex unit. The duplex process redirects the paper, allowing information to be printed on both sides of a single sheet. For duplexing, paper can be handled either inside the main unit or using external duplex units. Misfeed detection uses a combination of sensors along the paper path to track the progress of each sheet of paper. These sensors help detect paper jams, determining when and where a jam takes place Finally, after they are printed, the sheets can be stacked, sorted, directed to various output trays or bins, stapled, punched, or otherwise processed. Finishing processes can take place inside the main unit itself or can be handled by a finishing unit. Paper Path The paper path is, basically, the path that the paper travels from the paper source to the output tray. Most machines have a branching paper path--the paper can come from more than one source, and can be directed to more than one finishing process or output tray. Most paper paths can run through all six processes. There are two basic designs for the paper path. Most machines use a variation of these. 1 April 2001 Page 6 Handling Paper Paper Path Vertical Path Here, the paper is stored in the lower portion of the machine. Each sheet is fed from the paper source, transported vertically up the machine, then fed to the registration rollers and development section. Sometimes a shorter, straight path runs from the by-pass tray, this can be used to handle paper stocks that cannot run through the main paper path. Duplexi