Patent GB-1012687-A (GB)
Title: Photographic printing apparatus
IPC: G03B27/22
Filed: 1962-10-09
Abstract: 1,012,687. Photographic printing apparatus. PAKO CORPORATION. Oct 9, 1962 [Oct 9, 1961], No. 38274/62. Heading G2A. A contact printing apparatus comprises a negative support shaped as a convexly curved surface, through which the light passes, and a strip of light-sensitive material along which the negative is to be printed repetitively, the strip being flexed away from the support while it is moved along from one printing position to the next, and then drawn taut against the negative on the support surface when the exposure is to be made. The apparatus is intended for the printing of additional indicia, e.g. a greetings message, adjacent the normal exposed image area on a light-sensitive film strip. The apparatus as shown in Fig. 1 is formed in three sections, the left hand section 10 in which the latent image is printed on to the film, the central section A in which the auxiliary indicia is printed, and the right hand section 138 which is a magazine housing a take-up spool 140. The film strip 12, in passing from one section to the other, is taken through lightlocks 28, 130 and 142. During its passage, it is conveyed by various rollers. Rollers 16 and 122 are mounted on pivoted arms 18, 124 respectively biased by springs 19, 128. Rollers 62, 88 are compound rollers driven by friction clutches, so that as the movement of the film strip stops, the drive roller part of each roller also stops. The lamp housing and support E for the indicia negative, which is mounted in the central section A is shown in more detail in Fig. 8. This has a front wall 188, rear wall 190, a base plate 174, and the upper edges 192, 194 are shaped to an arcuate curve. On this is fixed a curved transparent plastics sheet 173 which forms the support for the actual negative C, which is secured in position by tape strips, and located by marginally placed pins 206, 208. The exposure lamp 242 is positioned so as to be substantially at the centre of the arcuate curve formed by the negative support, and extends into a lower part 244 of the housing which also contains a timing mechanism. Mounted adjacent one end of the support 173 is a roller 216 carried by a pair of spring loaded brackets such as 210, pivoted as at 185, and mounted adjacent the other end is another roller 238 carried by a pair of spring-loaded brackets such as 226, pivoted as at 228. This housing E can be removed bodily from the apparatus, to facilitate threading the photographic paper 12 through from exposure chamber 10 to take-up magazine 138, the part in the central chamber A being as shown by the dotted lines P. The housing E is attached to the main body of the apparatus by trunnions 180 which can slide into slots 254 in flanges 250 depending from the main body. Pivoting on these trunnions, the housing E hangs downwards in the position shown in broken lines in Fig. 1. It is then swung upwards into chamber A, a catch 264 engaging a hook 268 to lock it into position. As it enters chamber A, the curved negative support 173 engages against the paper 12, drawing it upwardly from position P. At the same time, roller 216 engages against friction roller 62, with the paper 12 between them, and also roller 238 engages against the other friction roller 88, also with the paper between them, and laid along the mask C on support 173 ready for printing. Thus a single upward pivoting movement positions housing E properly within chamber A, and a single downward pivoting movement brings it out of the chamber, leaving the latter free for adjustment or threading of the paper, or changing the mask. The diameter of roller 62 is larger than that of roller 88, so that the difference in the rate of linear travel of the paper under these tow rollers causes it to take up the looped formation shown by the broken lines D. Thus when the paper is actually moving, it is flexed as at D, and so is out of direct contact with the negative C, thereby preventing abrasion of one by the other. The print paper 12 is fed intermittently from the printing section 10. When transport from section 10 stops, roller 62 stops. Roller 88 continues until the slack in loop D is taken up, and the paper is drawn taut against negative C, then roller 88 stops also. A control mechanism now simultaneously energizes lamp 242 and the timer mechanism 244 which controls the exposure period. The message of indicia on the negative mask C is thus printed on the sensitive paper 12 adjacent the photographic image previously printed thereon in section 10. The position on paper 12 at which the indicia on the negative mask is printed can be varied in the following manner. Roller 21, over which the paper passes, is at the end of a pivotable arm 18, and is also held in a U-shaped clamp 21 slidable on a graduated arm 23. The clamp can be secured in any position by screws 25. Suppose that the indicia is being printed at point X. Assuming the paper to the left of roller 14 to be stationary, if clamp 21 and hence roller 16 are moved downwards along arm 23, when the excess of paper is taken up, point Y on the paper is now at the previous position of point X. Thus the indicia will now be printed at point Y.