Apparatus and process for in-mold labeling

摘要

A process for use in an in-mold labeling application utilizes a rolled label sheet having a multiplicity of pre-printed non-adhesive labels and a pre-printed registration mark associated with each of the labels, the process detecting each of the registration marks to alignment the label sheet in a predetermined longitudinal position before labels are cut therefrom, conveying the rolled label sheet forward or backward, cutting one or more labels from the label sheet, forming a controlled loop in the label sheet, detecting each of the registration marks for aligning the label sheet in a position of registration, providing a hold down vacuum for maintaining the label sheet in a position of registration during conveyance to a predetermined label removal position, and releasing the hold down vacuum to permit removal, by an external pick and place device, of one or more of the previously-cut labels.

主权项

1. A process for supplying labels for use in an in-mold labeling apparatus, comprising:
providing a label stock roll containing a continuous rolled label sheet having a multiplicity of non-adhesive labels pre-printed thereon and having a registration mark associated with each of said labels also pre-printed thereon; controllably unwinding a free end of said label sheet from said label stock roll; maintaining a constant tension in said label sheet as it is being unwound from said label stock roll; detecting one or more distinguishing features on said label sheet; laterally justifying said label sheet based upon detection of said one or more distinguishing features; detecting each of said registration marks pre-printed on said label sheet; providing a set of driven pinch rolls for clamping said free end of said label sheet therebetween and for moving said label sheet in a forward direction to a predetermined longitudinal position of registration with respect to said detected registration marks; providing a circumferential die cutter positioned to receive said free end of said label sheet from said set of driven pinch rolls; rotating said die cutter in a forward direction to a calibration position thereof for cutting one or more of said labels from said label sheet; providing a passive float roll under which said free end of said label sheet is received from said die cutter; applying a downward force on said passive float roll sufficient to create a controlled loop in said label sheet for maintaining a desired tension therein as it exits said die cutter; providing a driven vacuum conveyor positioned horizontally for receiving said label sheet from said passive float roll and for conveying said label sheet along said vacuum conveyor; detecting one of said registration marks on said label sheet after said label sheet has entered said vacuum conveyor; moving said label sheet in a forward direction on said vacuum conveyor to a predetermined longitudinal position of registration with respect to said registration mark detected after said label sheet has entered said vacuum conveyor; applying vacuum to said vacuum conveyor to maintain said label sheet in said position of registration on said vacuum conveyor; conveying said label sheet, maintained in said position of registration, to a predetermined label removal position on said vacuum conveyor; releasing vacuum to said vacuum conveyor after said label sheet has been conveyed to said label removal position to permit removal, by an external pick and place device, of one or more of said labels previously cut from said label sheet by said die cutter; and rotating said set of pinch rolls in a reverse direction to move said label sheet backward to a position of detection of a nearest one of said registration marks to thereby verify the longitudinal position of said label sheet and to eliminate any slack in said label sheet.