| 摘要 |
An improved marking gun for printing and applying adhesive price labels and the like, carried by a tape backing, the gun being of the type having a printing head connected to an operating trigger for imprinting the labels and wherein the improvements include a drive drum having radially projecting teeth for engagement with perforations in the label backing tape together with a pressure roller geared to rotate with the drive drum and exert a sufficient pressure on the backing tape to hold it against the drive wheel such that when the drive drum and pressure roller are initially rotated by the action of squeezing the marking gun trigger, the pulling force thereby exerted on the backing tape is less than the frictional force exerted by the printer which must necessarily be overcome to pull the backing tape and the labels through the printer. In this way, self-indexing is thereby accomplished because the initial rotation of the drive drum and the pressure roller cause the backing tape to slip until the projecting teeth of the drive drum mate with the spaced apart perforations in the backing tape. In the preferred embodiment, the printing head is also spring-coupled to the trigger to provide a constant printing force against the labels to be impressed.
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