# Scanner Mechanism

The scanner mechanism of WF-C878Ra/WF-C878R is composed of the CIS Modules and the Scanner Motor*¹ for driving the Scanner Carriage. As the light source for scanning, an LED is used for its long life and less power consumption.
To support document scanning of up to A3, seven reflective photo-interrupters are mounted for document size detection.

*1: Because the scanner motor is a DC motor, there are an encoder and scale to control the motor installed.