This maintenance manual contains the basic knowledge required for after-sales service of the LF6012MFP laser printer. It covers the features and technical specifications of the printer, installation and basic operations, operating principles, disassembly and reassembly, routine maintenance, maintenance mode, and repair and troubleshooting. The appendix provides information on product serial numbers, roller diameters/circumferences, drum life and print quantities, self-check methods, connection diagrams, and circuit diagrams.