Mark reader with improved mark sensing heads
AssigneeBourns, Inc.
InventorLoren Roger Davis
Life of this patent
Estimating the term…
Abstract
A document reader having a pair of improved sensing heads for reading marks on both sides of a document. Each head comprises a body portion equipped to transmit radiation onto a document and sense radiation reflected back from marks on the document. A substantially transparent, ultra high molecular weight polyethylene film secured to the body portion over the transmitting and receiving apparatus shields the body portion from wear by passing documents. With the film in place it is possible to avoid wrapping the documents about the sensing heads, a procedure that is otherwise desirable for accurate mark reading, and thereby further reduce wear.
Claims18
In a document reader having a radiation source, a sensing head for directing radiation from said source onto a document and sensing radiation reflected back from the document, a readout means for producing a readout corresponding to the sensed radiation, and means for driving a document past said sensing head, wherein the improvement comprises a sensing head comprising:
- a body portion,
- transmitting means lodged in said body portion for transmitting radiation from said source onto a passing document,
- receiving means lodged in said body portion for receiving radiation reflected by a document and direction said radiation to said readout means, and
- a substantially transparent, ultra high molecular weight polyethylene film secured to said body portion and overlying said transmitting and receiving means to separate a document being read from said body portion by substantially the film thickness.
A sensing head suitable for use in a document reader, said head comprising a body portion, transmitting means lodged in said body portion for transmitting radiation from a radiation source onto a document passed by the sensing head, receiving means lodged in said body portion for receiving radiation reflected off the document, and a substantially transparent, ultra high molecular weight polyethylene film secured to said body portion and overlying said transmitting and receiving means.
Apparatus for reading marks on both sides of a document, comprising:
- a radiation source,
- a pair of mark sensing heads oriented in mutually opposite directions to read opposite sides of a document transported between them, each of said heads comprising a body portion, at least one pair of transmitting and receiving means for respectively transmitting radiation from said source onto a document transported between the heads, receiving radiation reflected off a document, and directing, said radiation to said readout means, and a substantially transparent, ultra high molecular weight film secured to said body portion and overlying said transmitting and receiving means pairs,
- a readout means for producing a readout corresponding to the received radiation, and
- means for transporting a document between said sensing heads.
Dependencies are inferred from the claim text.