Browse Prior Art Database

PRINTHEAD DESIGN FOR THERMAL MAGNETIC RECORDING

IP.com Disclosure Number: IPCOM000025431D
Original Publication Date: 1985-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 112K

Publishing Venue

Xerox Disclosure Journal

Abstract

In Figure I, it is illustrated that magnetic latent images have maximum magnetic developer or toner holding force when they are recorded by a linear array of transducers, if the latent. image comprises continuous bars 12 rather than discrete pixels 14 and if these bars are aligned perpendicular to the direction of the DC magnetic field (indicated by arrow 13) with which the magnetizable layer of the magnetic recording medium 16 is pre-recorded. For clarity, a portion of one bar 12 is shown enlarged as bar portion 15 and one pixel 14 is shown enlarged as pixel

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XEROX DISCLOSURE JOURNAL

PRINTHEAD DESIGN FOR THERMAL MAGNETIC RECORDING
Robert N. Goren

Proposed Classification
U.S. CI. 346/74.1 Int. CI. Gold 15/06

II - I- a4 FIG. 2 FIG 3

FIG. 4

Volume 10 Number 3 May/June 1985 I27

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PRINTHEAD DESIGN FOR THERMAL MAGNETIC RECORDING (Cont'd)

In Figure I, it is illustrated that magnetic latent images have maximum magnetic developer or toner holding force when they are recorded by a linear array of transducers, if the latent. image comprises continuous bars 12 rather than discrete pixels 14 and if these bars are aligned perpendicular to the direction of the DC magnetic field (indicated by arrow 13) with which the magnetizable layer of the magnetic recording medium 16 is pre-recorded. For clarity, a portion of one bar 12 is shown enlarged as bar portion 15 and one pixel 14 is shown enlarged as pixel

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In a typical thermal magnetic recording process, the magnetic recording tape is normally DC pre-recorded in the same direction as the tape motion. Recording solid bars orthogonal to this direction would be extremely difficult, because the recording head gap would have to be page width rather than a nominal length of a fraction of 1 mm. For thermomagnetic latent image recording, the pre- magnetized tape would be passed over thermal heating transducers or elements in the presence of a reverse DC field to that of the pre-magnetization, so that in an imagewise fashion, some portions of the pre-magnetization have their polarity or magnetization direction reversed. The fringe fields between the different magnetic polarities produce the toner holding forces. Generally, the pattern of isolated pixels 14 in Figure 1 is undesirable in terms of toner holding force and thus, the developable image density. However, this is the pattern which is normally produced by conventional thin and thick film thermal recording heads, except at unacceptably high power levels.

Figure 2 shows the geometrical design of a con...