Browse Prior Art Database

Character Reader

IP.com Disclosure Number: IPCOM000082056D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Fan, GJ: AUTHOR [+2]

Abstract

A system has been provided for reading characters printed by a magnetic jet ink process wherein the characters have high-magnetic permeability.

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Character Reader

A system has been provided for reading characters printed by a magnetic jet ink process wherein the characters have high-magnetic permeability.

Conventional magnetic ink jet printing employs an ink that comprises a colloidal suspension of superparamagnetic Fe(3)O(4), and the latter displays little, if any, magnetic remanence that can serve as a detectable source of flux to be sensed by a reading head.

In Fig. 1 is shown a cross section of a system for sensing such ink, which consists of regions (inked portions) having high permeability and uninked regions having only unity permeability. The magnetic inked lettering 2 is shown, in exaggerated form, on paper 4. The lettering or inked character 2 is shown in Fig. la and consists of inked regions of high permeability surrounded by white or uninked regions of unity permeability.

The sensor for the lettering or character 2 comprises a nonmagnetic substrate 6 upon which is deposited a conductive film 8, insulated film 10, a magnetoresistive (MR) sensing element 12, embedded in the insulation 10, and a second conductor 14. Electrical currents flowing through conductors 8 and 14, normal to the plane of the drawing, are opposite to each other and the currents in each can be adjusted so that the net magnetic field being sensed by the magnetoresistive strip 12 is zero.

However, where the MR strip 12 is over the inked portion of a character 2, two images or virtual conductors appear under the character so that the MR sensor 12 now "sees"...