Tuesday, November 9, 2010

Label Sheet Feeding

Sheets of labels can be troublesome for pickup rollers because of their relatively slick surface on the back. Even new pickup rollers can experience traction failures on them. There is some traction force adjustability in Lexmark's autocompensator arms that may help. Here's a view of it in a T640 add-on tray.

The light spring that extends down the upper side of the autocompensator arm is a counterbalance spring. It's there to limit the pressure the pickup tires can exert when they're turning, so that multiple pickups don't occur.

Note the clip that anchors the end of the spring -- that clip's position is the adjustment. The clip in the photo is set at design centre.

For trays that feed label sheets, move the anchor clip to its uppermost/rearmost position, as in the following photo.

That minimizes the spring's counterbalancing effect, maximizing traction. (On the T640 and T650 integral trays, the clip has been deleted; there's a series of holes along the top of the arm that provide the same adjustability.)

I ran the pictured tray with ordinary paper after adjusting it for maximum traction, and had no double-feeding occur.

For label sheets, it's also wise to avoid third-party pickup rollers. From what I've seen of them, they just don't have the traction of the OEM parts -- either 40X0070 or 40X4308.

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