The present invention relates to a synchronization system for a facsimile system.
In a reciprocating plane-scanning type facsimile device, in particular, a device for both receiving and sending, main scanning is carried out by reciprocating linear motion of a carrier which carries a read-head and a write head. The U.S. patent application Ser. No. 770,784, now U.S. Pat. No. 4,075,664 is an example of that device. According to said prior art, the movement of the carrier in the receiving station is initiated by a synchronization signal sent from the transmission station, thus the operation of the receiving station is synchronized with the operation of the transmission station. Said synchronization signal is, in said prior art, sent from the transmission station to the receiving station for every one way trip of the carrier. That is to say, the synchronization signal is sent out just when the carrier starts from the left extreme end to the right, and the synchronization signal is sent out again just when the carrier starts from the right extreme end to the left. Thus, a pair of synchronization signals are sent out for every both way trip of the carrier from the transmission station to the receiving station.
However, in said prior synchronization system, there is the disadvantage that the carrier in the receiving station can be initiated at the right extreme end by the synchronization signal from the transmission station when the carrier stays at the left extreme end, and the carrier in the receiving station is initiated to the left extreme end by the right synchronization signal. This kind of synchronization error occurs in particular when the receiving station does not receive some of the synchronization signal due to noise and/or intermittent breakdown in a communication circuit. If such synchronization error occurs, the pattern reproduced in the receiving station is the inversed image of the original pattern in the transmission station.