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Photo Cell Patent for Page Turner
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A patent for a photocell and control circuit for an automatic page turner developed
by Robert J. Varson and Robert I. Johnson awarded on August 4, 1970. The technology
was designed to be used to coordinate the operation of a camera and an automatic
page turner.

The U.S. Census Bureau and its employees have a long history of developing and patenting new technologies to improve census taking, data processing, and tabulation. Some of these technologies—like Herman Hollerith's tabulator—revolutionized data processing and computing. Other technologies played a less visible, but vital role in enumerating our nation's population, businesses, farms, and governments. Some of these patents include:

Camera used in conjunction with the Automatic Camera and Loose Sheet Turner Using Vacuum Conveyor Belts. The camera automatically photographed multiple sheets in sequence.

Floating-Point Keypunch Machine. A keypunch machine to record a floating-point count in a card.

Automatic or Multiple Programmer. Used in conjunction with the Automatic and Loose Sheet Turner Using Vacuum Conveyor Belts to automatically arrange, flatten, and photograph sheets of paper in sequence.

Automatic Sheet Turner Using A Rotating Vacuum Head. An invention used to automatically turn and flatten the sheets of a booklet when the pages of the booklet are to be photographed on microfilm.

Automatic Stencil Cutter. An invention related to an automatic stencil cutter for inscribing intelligence in response to sensed coded information, like that found on a punch card used by data processing machines.

Apparatus for Measuring Area. An apparatus for measuring area, particularly areas of irregularly-shaped pieces of sheet material, such as pieces or cut-out portions of maps, graphs, aerial photographs, etc.

Photocell and Control Circuit for an Automatic Page Turner. An invention used to coordinate the operation of a camera and an automatic page turner, and to test and control the operation of the turner, whereby the pages in a bound volume can be automatically turned, flattened, and photographed in sequence.

Automatic Camera and Loose Sheet Turner Using Vacuum Conveyor Belts. An invention used to photograph multiple loose sheets, feeding each sheet in sequence using a moving conveyor belt and automatically positioning each to be photographed. A second conveyor automatically turns the sheet so the reverse side can be photographed.

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Source: U.S. Census Bureau | Census History Staff | Last Revised: December 08, 2021