Patent GB-1224752-A (GB)
Title: Facsimile reproducing method and apparatus
IPC: G03F3/08
Filed: 1968-03-13
Abstract: 1,224,752. Facsimile systems. PRINTING DEVELOPMENTS INTERNATIONAL S.A. 13 March, 1968 [15 March, 1967], No. 12165/68. Heading H4F. In a system in which an image on a sheet is scanned point-by-point to convert the tonal values into at least one image signal fed to a second scanning unit which synchronously scans image-receptive material to reproduce the image in response to said signal, a multiple tone mask is mounted in separated relationship from the sheet and synchronously scanned to convert different tones on the mask into at least one mask signal which controls the flow of said image signal to the second scanning unit. By this means a second image is superimposed on the image reproduced from the copy sheet, the sheet being scanned by a mechanical linkage which enables the reproduced image to be of a different size to the original. As shown in Fig. 1, a sheet 137 such as a colour transparency is mounted on a frame 136 carried by a carriage 134, and is scanned by a light 15, interrupted by an electro-optical shutter 16, which is focused by a lens 19 into a spot 18. The light beam transmitted through the transparency is transmitted via optical system 21 to 26 to mirrors 27, 28, 29 which direct separate light beams through blue, red and green filters 34, 35, 36 to conventional colour correction and black printer circuits 38. The signals from circuits 38 are supplied to magenta, cyan, yellow and black glow lamps 40 to 43, respectively, which co-operate via projectors 114 with corresponding photo-sensitive films 110 on a rotatable drum 106 driven by a motor 100. The projectors 114 are mounted on a carriage 116 slidable on ways 118 which is given a step-by-step displacement by a drive unit 120, the carriage 134 being mounted for similar movement on ways 118. A cam 107 is rotated by the motor 100 and co-operates with a follower 125 to reciprocate a member 132 linked to the carriage 134 to correspondingly move the sheet 137 about an axis parallel to the axes of the ways 118. A bracket 140 on the carriage 116 and linkage 142, 145, 149 pivoted at 146 to the base-plate 101 are arranged to move the carriage 134 at a rate directly proportional to but smaller than that of the carriage 116, the linkage between cam 107 and frame 136 being similarly arranged to reduce the rate of reciprocation proportionally with respect to the rate of scanning of the films 110. A mask 170 bearing information to be superimposed on the colour separation images is mounted on a transparent drum 155 on the carriage 116 which is rotated synchronously with the drum 106 through gears 161, 162, a spline shaft 163 allowing the drum to be axially displaced by the drive 120. The mask 170 is scanned by light from a source 52. and the light transmitted through the mask is directed by lenses 61, 62, 63 to a photo-cell 60. Photo-cell 60 drives an amplifier 70 including a threshold stage to eliminate noise, which in turn operates a trigger 72, Fig. 2, which produces a pulse each time an information element on the mask is scanned. The pulses from trigger 72 disable the gates 74 to 77 in the outputs of circuits 38 and enable gates 82 to 85 so that predetermined colour information signals as determined by the setting of potentiometers 92, are supplied to the glow lamps 40 to 43.