Patent GB-289895-A (GB)
Title: Process for producing photo-prints and photo-copies
IPC: G03C1/73
Filed: 1928-05-04
Abstract: 289,895. I. G. Farbenindustrie Akt.- Ges. May 6, 1927, [Convention date]. Addition to 286,233, Z86,736, and 289,386. Processes employing light-sensitive dye components.-The processes of the parent Specifications are modified by employing as the sensitive medium instead of a salt of 1 : 2-naphthoquinone- 4-sulphonic acid or substitution products thereof, a salt of any other sulphonic acid of 1 :2- naphthoquinone, such as 1 : 2-naphthoquinone-6- sulphonic acid, 1: 2-naphthoquinone-3 : 7-disulphonic acid, or a halogen-, oxy- or other substitution product thereof, such as 8-oxy-1 : 2-naphthoquinone-3 : 6-disulphonic acid. In au example, paper provided with a layer of sodium 1 :2-naphthoquinone-3: 6-disulphonate and resorcinol is exposed to light and developed with vapour containing ammonia, yielding a violet positive which turns bordeaux on exposure to air. Contact printing frames.-Relates to registering-devices for adjusting sets of printing-plates on mounting-blocks in multi-colour printing, or sets of photographic plates or transparencies on the glass plate of a photographic printing-apparatus, or for other purposes, and particularly to devices of the kind having lateral guide-members over which can move a longitudinal guide-member having a straight-edge or locating-bar adjustable along it. According to the invention, adjustable locking-members are provided for holding the longitudinal guide-member and the locating-bar in adjusted position, and independent means is provided for effecting a fine adjustment of these parts. In a construction adapted for registering printing-plates, a mounting board or plate a is provided with parallel guide-members b and with a transverse bar c, to form a three-sided frame, within which mounts for the printing-plates are secured by the aid of locking-bars g, which can be set in various positions by means of pins engaging holes a<1>, the mounts being fixed by means of wedges or printer's quoins. A longitudinal guide-member d is adapted to slide over the lateral guide-members b, and carries a sliding-shoe c, to which is hinged a locating-bar f. Two locating-pins f<1>, f<2>, one of which is adjustable, are carried by the locating-bar, and are adapted to engage holes in the bevelled margins of the printing-plates. The pins are movable vertically in the locating-bar to effect their engagement and disengagement, or two pins may be mounted in a crosshead carried by a sliding rod. The pins may be carried by an adjustable extension of the locating-bar. The guide-members b are recessed to receive racks b<2>, which are engaged by toothed locking-blocks d<1>, d<2> at opposite ends of the longitudinal guide-member d, one of the locking-blocks being retractable by means such as an eccentric. The racks b<2> can be adjusted endwise by means of micrometer devices b<5>, so as to give a fine adjustment to the guide-member d. The member d also carries a rack d<3>, which is engaged by a movable toothed block c<1> on the sliding shoe c, that carries the locating-bar. The rack d<3> can be finely adjusted by means of a micrometer device d<5>. Scales are provided on the guidemembers b, d. The units to be adjusted may have registration marks instead of holes, and other co-operating means than the locating-pins may then be used. The mounting-frame may be dispensed with, or replaced by a frame separate from the guide-members. The toothed racks may be replaced by plain bars, and friction or other locking-devices may be employed.