Browse Prior Art Database

Facsimile Equipment and Document I/O Device

IP.com Disclosure Number: IPCOM000077938D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Bachtold, W: AUTHOR [+3]

Abstract

In a facsimile system, the picture area is partitioned into N equal subsections which are simultaneously scanned by a multiple-beam array, and the N parallel scan signals are dynamically multiplexed for transmission. Thus scanning time is reduced and utilization of the transmission channel optimized.

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Facsimile Equipment and Document I/O Device

In a facsimile system, the picture area is partitioned into N equal subsections which are simultaneously scanned by a multiple-beam array, and the N parallel scan signals are dynamically multiplexed for transmission. Thus scanning time is reduced and utilization of the transmission channel optimized.

The principle is shown in Fig. 1 in which transmitter and receiver are combined to simplify representation, though they are often separate units. The drum rotates, and also makes a slow continuous or a stepwise motion in an axial direction.

For transmitting, the document is scanned by N parallel light beams and the reflected light detected by N parallel photosensors. Beams may be guided by glass fibers. Output signals from photosensors are sampled at regular intervals and converted to binary signals by a threshold decision. A multiplexing stage follows to interleave the N binary signals for transmission. Instantaneous Priority Multiplexing as described in U. S. Patent 3,647,949 is used to allow optimum utilization of channel capacity. In this method, only 1-bits are transmitted by providing the address of the respective sensor, and simultaneous occurrence of two or more 1-bits is resolved by a priority scheme.

When receiving, signals are demultiplexed by address decoding and accordingly distributing 1-bits to N lines, which control switches for N parallel light sources. Thus, on a photosensitive material carried by a moving drum, the transmitted picture is reproduced in N parallel subsections.

The photosensors can be implemented as a linear array of p...