GB450528A - Improvements in and relating to methods and means for the control of one movable member in respect of other movable members - Google Patents

Abstract

450,528. Automatic control systems. SOC. ANON. DE PUBLICATIONS PERIODIQUES (IMPRIMERIE E. DESFOSSES), 13, Quai Voltaire, Paris. Oct. 16, 1934, Nos. 29642 and 29643. Void [Abridged as open to inspection under Sect. 91 of the Acts, April 17, 1935]. [Class 38 (iv)] [See also Group XVI] Registration.-Apparatus for determining the relative positioning of several prints or the like on the same support, for example multicolour prints on a web in a rotary printing- machine, comprises means on some of the printing-rollers or the like for producing register marks on the prints or the like, and means comprising photo-electric cells and relays for automatically controlling register. For multicolour printing of a web b, the web passes over adjustable registering-rollers a<20>, slidably supported in guides a<30>, which are arranged between the printing-rollers a<1>. For each or some of the latter there are provided marking means, either formed on the edge of the cylinder or on a separate member attached thereto, which print on the web, so that when all the cylinders are in the correct relative position, the marks A partly overlap or are situated at definite distances from one another. The marks may be in the form of dots, circles, &c., and may serve for transverse as well as longitudinal registration. Alternatively other marks m in the form of a straight line printed by each cylinder, and all overlapping when in register, or of a number of broken straight lines printed by each cylinder but forming one straight line when in register, may be used. A number of intermittent light sources illuminate a number of photo-electric cells, there being as many light sources as cylinders, but two cells to each light source which are displaced somewhat to one another along the path of the web, so that if a mark arrives early or late a cell is energized and operates a relay to adjust appropriately the position of a registering-roller a<20>, while if the particular printing cylinder is in its correct position the appropriate mark obscures both cells at the moment of illumination ; in this case the marks are in groups, those forming a group being equidistant from one another. A continuouslyilluminated light source may be used, and in this case the registration marks are in the form of transparent strips crossing opaque bands printed by each cylinder along the edge of the web. When the cylinders (two only being used in this system) are in register, the two transparent strips form a straight line and, upon reaching two photo - electric cells arranged side by side beneath the path of the bands printed on the web, have no effect thereon. If there is lack of register, one strip arrives before the other and energizes its cell to initiate a correction, which ceases when the second strip arrives at the second cell. The device may be applied to printing on both sides of a web.