Abstract: A computer is used to calculate the location of a target, customize the target to conform to the lens, frame and patient characteristics of each individual job and automatically compensate for parallax in the apparatus. A convenient open work surface is provided for the operator to position the lens blank on a non-skid surface. The block is applied at a constant limited force in a manual or automatic mode of operation on either frame or optical center. The offsets for positioning the lens blank are calculated within the blocker based upon frame and patient data. This data can be input directly or can be downloaded from a database. These offsets determine the location of the target relative to the optical markings on the lens blank. The amount the target is offset is scaled automatically to compensate for the fact that the lens blanks are on a work surface above the electronic display. A customized target is displayed.

Abstract: A tape deck providing means to drive and control a file reel and a machine reel including a vacuum source and a capstan drive means, the tape deck including a first vacuum column of relatively wide width and short length extending upwardly and at an acute angle to the vertical plane encompassing the axis of the file reel and machine reel, and a second relatively wide, short length vacuum column below the first vacuum column and having an axis intersecting the axis of the first vacuum column at an acute angle, the second vacuum column having a transverse end wall at an angle to the second vacuum column outer wall, the sources of vacuum being applied to the vacuum columns, the capstan being positioned at the entrance to the second vacuum column so that a short length of tape extends from the capstan to the exit of the first vacuum column, the tape being wrapped 180.degree.