| 摘要 |
<p>1388897 Contact printing HOECHST AG 20 March 1972 [27 Aug 1971] 12804/72 Heading G2A A copying machine including a feeding and cutting device for reproduction material in web form also includes a device for sensing the length of an original to control said devices in order to supply from a travelling web of said material a portion of a suitable length in relation to the length of the original, said sensing device including at least one control element for sensing the leading edge of the original and one for sensing the trailing edge, said elements co-operating with an electronic computer whose output is dependent on the rate of travel of the original. In the described embodiment there are two rolls 1, 2 of reproduction paper of differ- ent widths and two sets of control elements 21a, 21b, (21a' 21b') one or the other set controlling its related web according to whether the original 13 is fed to the machine on one side of the table 18 or the other. More than two webs may be incorporated with corresponding control sets. The control elements are adjustably mounted, Fig.3, on a lever 26 whose end passes over a scale 28, so that their positions may be varied to allow for originals having margins and hanging strips which are not required to be copied. Each web 3 or 4 passes through draw off rollers 5,6, reserve loops 16, 17, feed rollers 7, 8, cutting device 9, moveable guide means 10 and rollers 11 to roller 12 where it is associated with the original 13 and passed to a copying station. The sensing of the leading edge of the original, being fed by rollers 19 at a predetermined speed gives an impulse to the time computer which calculates a time delay dependent on the selected speed and also the characteristics of the feeding device. After this delay and considering the web 3 to be selected the feed roller 7 causes the web of material 3 to be fed to rollers 11 at the same speed of travel as the original, taking up the loop 16 actuating a switch 49 causing the draw off rollers 5 to operate to withdraw material at a speed greater than the speed of the original and restore the loop, this process being repeated several times depending on the length of the original. When the trailing edge is sensed an impulse to the computer causes it to calculate another delay after which the feed rollers are braked to standstill. After a further time delay the cutter is actuated. Voltage adjustment may be made by knobs 57, 58 for copying originals with hanging strips and to set the machine up for manual operation or to cut test strips from the webs to check exposure times.</p> |
