Browse Prior Art Database

Optical Means For End of Ribbon Sensing

IP.com Disclosure Number: IPCOM000051490D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Bullock, RL: AUTHOR [+3]

Abstract

In accordance with the present structure, the end of the ribbon passes between an optical detector and a reflective surface formed on a card holder. At the end of the ribbon, there is a transparent opening which permits light to be projected from the optical detector to be reflected off the reflective surface and back through the transparent area on the ribbon to the photosensor means contained in the optical detector. Thus, we have reflective sensing through an aperture at the end of the ribbon. This approach has an advantage over a direct optical transmission system through an aperture at the end of the ribbon because the relatively close distances required between the platen and the ribbon of present day high-speed printers leave little room for any kind of a photosensor on the platen side of the ribbon.

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Optical Means For End of Ribbon Sensing

In accordance with the present structure, the end of the ribbon passes between an optical detector and a reflective surface formed on a card holder. At the end of the ribbon, there is a transparent opening which permits light to be projected from the optical detector to be reflected off the reflective surface and back through the transparent area on the ribbon to the photosensor means contained in the optical detector. Thus, we have reflective sensing through an aperture at the end of the ribbon. This approach has an advantage over a direct optical transmission system through an aperture at the end of the ribbon because the relatively close distances required between the platen and the ribbon of present day high-speed printers leave little room for any kind of a photosensor on the platen side of the ribbon. The present apparatus has the advantage over using reflected areas directly on the end of the ribbon in that a reflective area on the ribbon would not remain stationary, i.e., in a fixed plane, but would flex as the ribbon moved to thereby interfere with reflection. The reflected area on the cardholder is, of course, fixed in its plane.

With reference to Figs. 1, 2 and 3, we will consider the advantages of the present method diagrammatically shown in Fig. 3 with some previous methods diagrammatically shown in Figs. 1 and 2. In Fig. 1, the conventional method is shown wherein light transmitted from emitter 10 is reflected...