Chapter 3 Theory Of Operation - Brother mfc-3420c Service Manual

CHAPTER 3 THEORY OF OPERATION

This chapter summarizes the scanner and printing mechanisms and control electronics. It also
provides information about sensors and their actuators. This chapter helps you to understand the
operating principles and isolate the source of a problem (troubleshooting).
3.1 OVERVIEW .................................................................................................................3-1
3.2 MECHANISMS ............................................................................................................3-2
3.2.1 Scanner Mechanism.........................................................................................3-3
3.2.2 Ink Jet Printing Mechanism ..............................................................................3-5
3.2.2.1 Paper pulling-in, registration, feeding, and ejecting mechanisms ..............3-5
3.2.2.2 Ink jet printing and capping mechanisms ..................................................3-8
3.2.2.3 Purging mechanism................................................................................3-11
3.2.2.4 Carriage drive mechanism .....................................................................3-16
3.2.3 Sensors and Actuators ...................................................................................3-17
3.3 CONTROL ELECTRONICS.......................................................................................3-20
3.3.1 Configuration..................................................................................................3-20
CONTENTS