GB905057A - Photo-electric reading device for an information bearer with marking-grid areas - Google Patents

Abstract

905,057. Sensing record-cards. DE STAAT DER NEDERLANDEN TEN DEZE VERTEGENWOORDIGD DOOR DE DIRECTEUR - GENERAAL DER POSTERIJEN, TELEGRAPHIE EN TELEFONIE. Jan. 24, 1961 [Feb. 3, 1960], No. 2749/61. Class 106 (1). A record card as described in Specification 845,050, having a number of columns of marking spaces each being in a light colour on a different coloured background, one of the spaces being filled in to indicate the data and each column having a synchronizing mark, is sensed by two identical sensing stations A, B, Fig. 1, each consisting of a row of photo-cells a-u equal in size to a marking space or the distance between them, the synchronizing marks being sensed by a group of three smaller photocells x, y, z and their outputs determine which of the photo-cells a-u shall be connected to storage means, the data stored from the two sensing stations A, B being compared. The transverse registry of the record is determined by the combination of photo-cells x, y and z which detect the synchronizing mark. The three signals are combined in circuit PS, Fig. 2, to produce an output on one of five lines 11-15, enabling one of five groups of gates. These correspond to normal registry (N) and displacements left (L), right (R), extreme left (UL) and extreme right (UR). To each of these groups of ten gates are connetted the appropriate ten of the data-sensing photo-cells a-u and there are ten output leads of which one will be marked according to the position of the filled-in space in the column being sensed to set one of ten triggers I-X. Stations A and B set the two groups of triggers I-X and Ia-Xa and these are compared at VG. A checking circuit C checks the one and only one of the triggers Ia-Xa is set. The background colour, e.g. a partially saturated red is such that it produces the same response in the photo-cell as an unfilled space. A filled space therefore produces a distinguishable signal.