Patent GB-1045304-A (GB)
Title: Improvements in or relating to photographic type composition
Inventor: MOYROUD LOUIS MARIUS
IPC: B41B17/10
Filed: 1963-04-01
Abstract: 1,045,304. Photographic type - setting. INTERNATIONAL PHOTON CORPORATION. April 1, 1964 [April 1. 1963], No. 12910/63. Heading B6W. In a method of photographically composing a line of characters by projecting images of the characters on to a light-sensitive surface from a continuously rotating matrix disc, the character images are projected by optical projection units, each associated with a specific group of character image positions forming an element of a line to be composed and each projecting an image to the associated line element when a matrix character of corresponding identity is momentarily illuminated in a projection position unique to the unit. Fig. 1 illustrates schematically apparatus where a film 2 has a line of characters projected on to it, the line being split up into a number of groups K 1 , K 2  &c., each group or element K being split up into character positions C 1 , C 2 , C 3  &c. The projection units 23 are positioned between the film 2 and a continuously rotating matrix disc 4 and each are associated with a projecting position L such as L 1 , L 2 , L 3  &C Each projection unit has associated therewith a flash lamp 13 whose flash timing is obtained by a circuit involving photo-electric pulses generated by a ring of transparent controlling slits 124, Fig. 5, provided around the disc 4 and operating as a pulse generator as explained in Specification 733,614. Fig. 5 illustrates a type of matrix disc which can be used. The disc 4 is split into four segments and each segment has four arcuately disposed character fonts, each character font at a different radius. In apparatus with a disc as illustrated in Fig. 5, one revolution of the disc will produce one complete line on the film 2. Assuming each element of the line has four characters, during the first quarter rotation of the disc a particular projection unit will project the first character in the element, that is C 1 . The next quarter rotation of the disc will project the second character of the element, the third and fourth segments of the disc as they pass the projection unit will similarly project the third and fourth characters on to the paper film 4 and thereby completing the element. Since each projection unit is associated with an element of the line, each element of the line will be completed for the one rotation of the disc. Various corrections are necessary to the projected image so that the projected image on the film is correctly aligned. Fig. 3 (not shown), illustrates a projection unit such as 23, which comprises a lens 52, an orientating device such as a dove prism 54 and a collimating lens 50 for defining a sharp image on the film 2. When the apparatus is set up the dove prism is adjusted so that the character image is correctly orientated on the paper film 2. All projection units, such as 23, are mounted on a machine frame 100, Fig. 7 (not shown): a plan view. Each projection unit such as 23, is provided with a tube 104, Fig. 6 (not shown) to control the passage of light emitting from the flashing unit 13. No problem arises about projecting a line onto the film 2 when the film is stationary. However, it is envisaged that the film will be moving continuously in the vertical direction. It is therefore necessary to allow for this movement so that all the characters of a line are situated on a common base line. Fig. 13 (not shown), illustrates what will happen if no corrections are made during one rotation of the disc. Consider Fig. 4 (not shown): assume the matrix 68 is moving in the direction of the arrow 90 and that a photo-sensitive film is moving in the direction of the arrow 92. Three light flashes from a flasher 66 gives three images 82, 84, 86. The film motion can thus be compensated for by timing the flash so that an early character is flashed late and a late character of the sequence is flashed early. The proper amount of timing compensation may be obtained by properly spacing the slits 124 of Fig. 5, illustrated in more detail in Fig. 9 (not shown). In this Figure the flash controlling slits are shown at 152 and the alphabet at 153. The controlling slits are spaced at distance s and the letters of the alphabet are spaced at distance d. Compensation for the film motion is automatically obtained by making distance s slightly larger than distance d, the difference depending on several factors, amongst which are the rotational speed of the disc and the speed of the film. The slit for A is shown at 152a, the slit for character B at 152b and so forth. It can be seen that there is a gradual decreasing of the distance between the base line of succeeding characters and their controlling slits. For example, the last character of the alphabet Z is, in this example, shown at the same level as its controlling slit 152z. Therefore as the alphabet and slits move in the direction of the arrow 154, the character A will be flashed relatively early with reference to a fixed location than the last character of the sequence Z, the difference in flash timing between A and Z being represented by the time the disc takes to travel the distance between the slit 152z and the location of the slit 152z if the spacing between the slits and the characters was the same, that is slit 150. Fig. 8 (not shown), illustrates the layout of a character for different fonts, the dimension W representing the maximum character height plus the image displacement during approximately one quarter of a revolution of the matrix disc. The dimension CS is proportional to the column widths or character spacing on the film. Fig. 14 (not shown), illustrates a modification of the matrix disc. In this disc the four fonts are very nearly circular. The segment, the same as the segment 122 in Fig. 5 is provided so that there is sufficient time for the flash lamp to recharge if the last character of a font is to be immediately followed by the first character of the font. A plurality of projection units are provided as in the above embodiment. However, with this disc, to complete one line of text, the disc has to rotate four times. With this arrangement a shutter mechanism is required and this is illustrated in Fig. 15 (not shown). For each revolution of the disc a cam 180 rotates through 90 degrees. As the segment 122 passes the reference position the cam follower 178 of the shutter 170 rides up the steepest part of the cam to shift the shutter one column or character width. Therefore, for four rotations of the disc, the shutter is displaced four times to provide four columns forming an element of the line to be composed. Fig. 17 (not shown), illustrates type composing where the letters or characters each have different widths. In this case the elements of a line are not split up into individual character columns but are split up into width units. Figs. 16 and 18 (not shown), both illustrate circuits which may be used for timing the flashes. The embodiment shown in Fig. 16 is similar to the flash control system described in Specification 733,614. In the circuit of Fig. 18, a magnetic or punched tape input is decoded in the converter 214 and signals obtaining to each character are passed along line 218 into the delay circuit 222 before passing on to lines 220 where the character identity codes are then loaded into the gates G 1 , G 2 , G 3  &c. and the - storage units 17-1, 17-2, 17-3 &c. A character width determining unit 210, such as described in Specification 741,209, is provided and the character widths are added into a width accumulator 216. Each accumulated width is fed into a storage unit with the associated character identity code. Separate adder units AR 1 , AR 2  &c., each associated with its particular storage unit, adds the correct amount of width units for justification purposes. The counter 224 is fed by pulses from a pulse generator of the type described above. As the disc 4 rotates and the number of character width units accumulate in a counter 224, this accumulation is compared in comparison circuits CC17-1, CC17-2 &c. and as identity occurs with each storage unit together with the amount of units added in the adders, a signal is sent to the flash unit associated with each storage unit.