Browse Prior Art Database

PAPER STACK HEIGHT AND MOTION SENSOR

IP.com Disclosure Number: IPCOM000025283D
Original Publication Date: 1984-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 69K

Publishing Venue

Xerox Disclosure Journal

Abstract

With reference to the figures, there is shown a sensor that will measure small displacements of a paper stack and the stack height. This invention proposal describes a single optical sensor which performs both functions.

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CEROX DISCLOSURE JOURNAL

2 I- 3

PAPER STACK HEIGHT AND MOTION SENSOR
Raymond
W. Huggins

Proposed Classification
U.S.
c1. 355/3
Int. C1. G03g 15/08

POINT SOURCE (LED)

FIG. I

POINT DETECTOR (b)

0 MOTIONAL

i

STACK HEIGHT

FIG. 2

FIG. 3

195 Volume 9 Number 3 May/June 1984

[This page contains 1 picture or other non-text object]

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PAPER STACK HEIGHT AND MOTION SENSOR (Cont'd)

With reference to the figures, there is shown a sensor that will measure small displacements of a paper stack and the stack height. This invention proposal describes a single optical sensor which performs both functions.

The sensor operating principle is shown in Figure la. Optical radiation from a point source is collimated by lens L2, and then focused onto a point detector by lens L1. It is obvious that an opaque object introduced into the collimated beam will reduce the energy incident upon the detector, and if a suitable field stop is placed in the beam, (Figure lb), the detector output will be approximately linear with the displacement of the occluding object.

If a stack of paper with the edge slightly raked is introduced between the lenses as shown in Figure 2, the collimated beam is occluded by the top sheet of the stack. Since the stack is raked, it follows that the degree of occlusion increases with the stack height, and the DC level of the detector output will therefore be inversely proportional to the stack height. Any small periodic displacement or motion of the stack will app...