This invention relates to a rack for feeding photosensitive material to be developed in an automatic developing device.
An automatic developing device has a plurality of tanks arranged in one direction and filled with developing, bleaching, fixing, stabilizing and other solutions. Photosensitive material is developed by being immersed in these tanks one after another. A rack is mounted in each tank and photosensitive material is fed through the rack.
Such a rack has a guide path for guiding photosensitive material, and a feed device for feeding photosensitive material through the guide path.
To save natural resourses and protect the environment, the amount of treating solution used in an automatic developing device should be limited to a minimum. For this purpose, there has been proposed a hollow rack having a body formed with a slit-shaped feed path, and rack plates provided on both sides of the rack body to define the feed paths. The rack plates are formed with a plurality of treating solution passages elongated in a width direction of the plates and arranged in a vertical direction. A slit-shaped nozzle is connected to each treating solution passage. Treating solution is blown from the nozzles against the photosensitive material which is being fed through the feed path.
When this slit type rack is immersed in the treating solution of each tank, air is inevitably trapped and remains in the treating solution passages. Such air is mostly expelled from the passages together with treating solution flowing through the passages. But it is difficult to completely expel air in the passages. Any remaining air tends to disturb the flow of treating solution discharged from the slit, making difficult uniform spraying of developing solution on photosensitive material. Thus, photosensitive material is developed partially quickly and partially slowly, so that the quality of the developed material tends to be unstable.
Also, by contact with the remaining air, treating solution tends to deteriorate.
In such an automatic developing machine, treating solution is circulated between the treating solution tank and a sub-tank communicating with the top of the treating solution tank to keep the solution temperature uniform. A heater is provided in the sub-tank to keep the solution temperature at a predetermined level.
A conventional slit type rack has its feed paths open at the bottom of the rack body. Treating solution in the rack body is discharged through the bottom openings into the treating solution tank. Thus, treating solution in the rack body cannot flow smoothly into a gap between the treating solution tank and the rack body. Due to poor circulation of treating solution in the rack body, it was difficult to uniformly develop photosensitive material with stable quality.
An object of this invention is to provide a slit type rack which can completely expel air remaining in the treating solution passages, thereby stabilizing the quality of developed material.
Another object of this invention is to provide a slit type rack which can smoothly circulate treating solution in the rack body, thereby improving the quality of developed material.