GB659187A - Improvements in or relating to apparatus for developing photographic printing papers - Google Patents

Abstract

659,187. Photographic developing apparatus. CELLOPHANE SOC. ANON. Feb. 16, 1949, No. 4289. Convention date, March 5, 1948. [Class 98 (ii)] Apparatus for the gaseous development of photographic printing papers comprises a fluidtight casing having a pair of lips defining a slot permitting ingress and egress of the sheets of paper, or two pairs of lips defining two slots respectively serving as ingress and egress slots, the said slot or each of said slots giving immediate access to a drive roller within the casing which co-operates with another roller or with a fixed element in the casing and is adapted to drive the sheets forward, the drive-roller being rubber-covered, and resilient material being provided between the drive roller, and a co-operating roller if any, and the associated lips, to render the casing fiuid-tight, the said casing being internally divided into at least two compartments, one of which communicates with the aforesaid slot or slots, while the other or each of the other compartments contains a source of developing gas, the wall or walls which separate the compartments being perforated to permit the passage of the developing gas therethrough. As shown, the casing 1 is slotted at 4, 5 and printing paper to be developed is fed through slot 4 and engaged in the nip of rollers 7, 8 which are rotated by a crank 9 on roller 7 to feed the sheet into a compartment 15 defined by perforated walls 13, 14 through which passes ammonia vapour from a vat 18, 19 in each chamber 16, 17. When the paper has been subjected to the gas for the required time, rollers 10, 11 are rotated by a crank 12 so that the sheet is fed out of the casing through slot 5. The drive rollers 7, 10 are rubber-covered and resilient packing material 23 is provided to prevent leakage of gas. The casing may be so shaped and the rollers 7, 8 and 10, 11 may be so arranged that the printing paper leaves the casing in a direction normal to the direction of entry. Another form is described in which the drive rollers co-operate with a wall of the casing to feed the printing paper; a modification is also described wherein a single drive roller co-operates with another roller or with a wall of the casing to feed the printing paper into and out of the casing. Specification 445,235 is referred to.