c. The rollers of the crossovers and racks move by means of a main drive shaft
run by a drive motor. Through a series of cogwheels and gears, the energy is
transferred to the rollers from this drive shaft.
d. No attempt will be made to cover all the mechanics of the crossovers and
racks because of the great variation between models. If a breakdown occurs,
maintenance personnel or the manufacturer will repair the processor.
The roller-transport system squeezes the chemicals into and out of film emulsion,
providing an agitating action, which promotes even processing and increases the speed
of reactions. A circulation-filtration system is used to boost this action. The circulation
pump recirculates the solutions through filters, keeping the chemicals properly mixed
and clean as well as in a state of agitation.
a. As each film passes through the automatic processor, the chemicals are
changed slightly. To offset the resulting deficiencies, new developer and fixer in
measured amounts are pumped into the solutions. This is called replenishment.
b. There are two tasks, called replenisher tasks, in which fixer and developer are
stored. The tanks are protected by dust covers and a floating lid in the developer tank
helps to reduce oxidation.
c. When a film is initially fed into the processor, it activates the micro switch
previously mentioned. The micro switch turns on the replenisher pumps and new
solutions are pumped into the system, which filter out dirt from the replenisher solutions.
d. Replenishment tanks should be checked weekly and refilled periodically.
Care should be exercised to ensure that the solutions are not contaminated.
a. The chemistry of the automatic processor is regulated and controlled by the
tempering system. As in manual processing, there is a time-temperature relationship.
(For example, more active chemicals and/or higher temperatures require less
developing time.) To maintain the desired temperature of the developer and fixer, a
heating device and automatic thermostat are used. Water is passed through a mixing
valve, so that it is 4 or 5 below the desired temperature, and then heated to the
desired temperature by the heating element in the machine. The required temperature
will vary from machine to machine. Use the manufacturer's recommended temperature
depending on the type of chemicals and the time needed for processing. The
temperature will usually be higher in faster machines. Through heat exchange, the
solutions are kept at similar temperatures. Temperature variation should not exceed 2.