GB1307778A - Digitally pulsed dielectirc line scan recorder - Google Patents

Abstract

1307778 Facsimile recorder EG & G Inc 19 April 1971 [11 March 1970] 24068/71 Heading H4F In a facsimile recorder three styli 36 mounted at approximately equal intervals on a driven belt loop 24 sequentially traverse successive lines in contact with the dielectric surface of a recording web 12 which has a conductive base and is stepped a line at a time by a metal roll 20 at earth potential, and brushes (104) connected to each stylus run along a metal strip (112) on an insulating bar 110 so that a facsimile signal fed to the strip causes the operative stylus to lay down a corresponding electrostatic pattern on the web 12. As described the facsimile signal consists of 1800 bits/line and clock pulses at that rate are also derived from the belt drive motor 38. The receiver stores the incoming signal, and when a complete line is available, provides a "line ready" pulse which sets a bi-stable. An AND gate receives the output of the bi-stable and the output of a light source-light fibrephoto-cell combination which detects when an oncoming stylus passes a predetermined position adjacent one edge of the web 12, and the resulting pulse, after being delayed to allow the stylus to cross the margin of the web, resets the bi-stable and enables the stored line to be clocked out of the receiver to the metal strip (112). Such an arrangement avoids the need for accurate spacing of the styli on the belt loop, and variations in the belt speed do not affect reproduction. A cam arrangement lifts each stylus as it crosses the edge of the web 12, Fig. 4 (not shown). The end of the web 12 is held by rolls 53 and 54 and forms a festoon 51 while an image is being recorded. An "end of picture'' signal causes a shearing blade 50 to be rotated through a small angle to cut the web on a blade 52, and the rolls 53 and 54 rapidly feed the festoon through a toner unit 60 and thence to a heated roll 154 to fix the image. When a photo-cell 58 senses the trailing edge of the festoon, a bar 70 is pivoted to position 74 to guide the next leading edge of web 12 between rolls 53 and 54 at a slow rate determined by the speed of roll 20 (rolls 53 and 54 are provided with a slip clutch). The cell 58 then detects the leading edge and stops the rolls 53 and 54 to form another festoon. The toner unit described uses a magnetic brush roller 152 and a mixture of toner and iron filings. The roller is formed of corrugated, alternately magnetic and non- magnetic washers and the toner-filing mixture is picked up thereby. Only the toner is held by the web 12 and is continuously replaced during recording.