Browse Prior Art Database

CRT Printer Copier

IP.com Disclosure Number: IPCOM000075609D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Heard, RS: AUTHOR

Abstract

A dual-beam CRT is utilized to effect both the printing of digital information and the duplication of printed information from an original document onto a photosensitive copy drum.

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CRT Printer Copier

A dual-beam CRT is utilized to effect both the printing of digital information and the duplication of printed information from an original document onto a photosensitive copy drum.

Flat-faced dual-beam CRT 11 is placed so that both beams 13, 15, sweep a horizontal line. Upper beam 13 is projected onto the face of original document 17 through moving document glass 19. Light scattered from document 17 is detected by a linear array of sensors 21, located parallel to the line scanned by the beam. The signals from sensors 21 are electronically summed and amplified by unit 23, which produces an electronic signal whose amplitude at any given time is proportional to the light scattered from the point on the document 17 where the beam 13 is projected at that time.

This signal is inverted by inverter 25 and converted to a digital signal by A/D converter 27. A/D converter 27 sets a threshold level thereby providing a binary output signal to system control, storage, and character generator unit 29. Unit 29 provides a digital output signal corresponding to the signal supplied it by A/D converter 27 to video amplifier 31 which, in turn, provides an output signal whose intensity modulates the lower beam 15 of the CRT 11. Unit 29 also provides deflection signals to ramp generator 33, to effect proper vertical deflection of the lower beam 15 for each horizontal scan. Lower beam 15 is reflected onto photoconductive copy drum 35 to form a latent electrostatic ima...