Brother International MFC-7050C Service Manual - Page 22

2.3 Sensors and Actuators This equipment has the following sensors: Sensor name Type Located on Hook switch sensor Mechanical switch Hook switch PCB in the handset mount Cover sensor Mechanical switch Cover sensor PCB Registration sensor Photosensor Main PCB Document front sensor Document rear sensor Photosensor Photosensor Document sensor PCB of the control panel PCB ASSY Document sensor PCB of the control panel PCB ASSY Ink empty sensor Photosensor Ink empty sensor PCB Carrier home position sensor Photosensor Sensor FPC • Hook switch sensor which detects whether the handset is placed on the handset mount. • Cover sensor which detects whether the top cover is closed. • Registration sensor which detects the leading and trailing edges of paper, which allows the controller to determine the registration timing and check paper jam. • Document front sensor which detects the presence of documents. • Document rear sensor which detects the leading and trailing edges of pages to tell the control circuitry when the leading edge of a new page has reached the starting position and when the scan for that page is over. • Ink empty sensor which detects the density of a printed ink-empty mark. • Carrier home position sensor which detects whether the carrier is in the home position. Each of the above photosensors consists of a light-emitting diode and a light-sensitive transistor. The ink empty sensor is a reflection type. Other photosensors are a photointerrupter having an actuator separately arranged as shown on the next page.