Developing unit with light-barrier scanning

摘要

The developing unit (20) has dosing pumps (58.1, 58.2) for regenerating the developing bath (27.1) and fixing bath (27.2). They are controlled by means of a circuit (40). Control is performed as a function of the traversing width (101) and traversing length of the photosensitive material (24). A light-barrier arrangement (43) with a single scanning beam (56) is used to determine the area thereby produced. A light-barrier carriage (44) is moved to and from over the operating width (100). Its infrared transmitter (55.1) emits a pulsed transmission beam (56.1) which is reflected by the traversing photosensitive material (24) and received by the receiver (55.2). The pulses are fed to the circuit (40) for evaluation. The photosensitive material (24) is guided by a low-reflection material-guiding roller (46) which is situated opposite the transmitter (55.1) and receiver (55.2) at a short distance (102). <IMAGE>