HP Color LaserJet Pro M452 And HP Color LaserJet Pro MFP .

Color LaserJet Pro M452Color LaserJet Pro MFP M477Troubleshooting 477MFPFor printer part removal and part numberinformation, see the Repair Manual.

HP Color LaserJet Pro M452 and HP ColorLaserJet Pro MFP M477Troubleshooting Manual

Copyright and LicenseTrademark Credits Copyright 2015 HP Development Company,L.P.Microsoft , Windows , Windows XP, andWindows Vista are U.S. registered trademarksof Microsoft Corporation.Reproduction, adaptation, or translationwithout prior written permission is prohibited,except as allowed under the copyright laws.The information contained herein is subject tochange without notice.The only warranties for HP products andservices are set forth in the express warrantystatements accompanying such products andservices. Nothing herein should be construedas constituting an additional warranty. HP shallnot be liable for technical or editorial errors oromissions contained herein.Edition 1, 10/2015

Conventions used in this guideTIP:NOTE:Helpful hints or shortcuts.Information that explains a concept or how to complete a task.Reinstallation tip: Reinstallation helpful hints, shortcuts, or considerations.IMPORTANT:CAUTION:Information that help the user to avoid potential printer error conditions.Procedures that the user must follow to avoid losing data or damaging the printer.WARNING! Procedures that the user must follow to avoid personal injury, catastrophic loss of data, orextensive damage to the printer.ENWWiii

ivConventions used in this guideENWW

For additional service and support informationHP service personnel, go to the Service Access Work Bench (SAW) at http://h41302.www4.hp.com/km/saw/home.do.Channel partners, go to HP Channel Services Network (CNS) at https://h30125.www3.hp.com/hpcsn.At these locations, find information on the following topics: Install and configure Printer specifications Up-to-date control panel message (CPMD) troubleshooting Solutions for printer issues and emerging issues Remove and replace part instructions and videos Service advisories Warranty and regulatory informationTo access HP PartSurfer information from any mobile device, go to http://partsurfermobile.hp.com/ or scanthe Quick Response (QR) code below.ENWWv

viFor additional service and support informationENWW

Table of contents1 Theory of operation . 1For additional service and support . 2Basic operation . 3Sequence of operation . 4Formatter-control system . 6Sleep delay . 6Auto On / Auto Off mode . 6Printer job language (PJL) . 7Printer management language (PML) . 7Control panel . 7Walk-up USB . 8Wireless . 8Low end data model (LEDM) overview . 8Advanced control language (ACL) overview . 8NFC . 9CPU . 9Input/output (I/O) . 9USB . 9USB hosts . 910/100/1000 networking . 9Fax . 9Memory . 9Firmware . 9Nonvolatile random access memory (NVRAM) . 9Flash memory . 10Random access memory . 10HP Memory Enhancement technology (MEt) . 10Engine-control system . 11Engine-control unit . 11DC controller . 13High-voltage power supply . 14Motors . 16ENWWvii

Fans . 17Low-voltage power supply . 18Over-current/over-voltage protection . 18Fuser control . 20Fuser heater protection . 21DC controller . 22Fuser heater safety circuit . 22Temperature fuse . 22Fuser control functions . 22Engine laser/scanner system . 23Laser/scanner failure detection . 24Image-formation system . 25Image-formation process . 28Step 1: Primary charging . 29Step 2: Laser-beam exposure . 31Step 3: Development . 31Step 4: Primary transfer . 32Step 5: Secondary transfer . 32Step 6: Separation . 33Step 7: Fusing . 33Step 8: Drum cleaning . 33Toner cartridges . 35Design . 35HP Cartridges with JetIntelligence . 36HP Cartridge Policy . 36Anti-theft or cartridge protection . 36Memory chip . 37Toner seal . 37Toner cartridge life detection . 37Developing unit engagement and disengagement control . 37Intermediate transfer belt (ITB) unit . 38Secondary transfer roller functions . 38Color self calibration . 40Engine pickup, feed, and delivery system . 41Photo sensors and switches . 41Motors, clutches, and solenoids . 43Feed speed control . 44Pickup and feed delivery features . 44Tray 1 (multipurpose)/Tray 2 (base printer) . 45Duplexing unit . 45Duplexing reverse and duplex feed control . 46viiiENWW

Duplex pickup operation . 46Jam detection/prevention . 46Input accessories . 48Tray 3 . 48Tray 3 paper feeder controller . 48Tray 3 motor control . 49Tray 3 paper pickup . 49Tray 3 pickup and feed functions . 50Tray 3 jam detection . 50Scanning and image capture system . 52Document feeder system . 53Document feeder simplex operation . 53Fax functions and operation (fax models only) . 54Computer and network security features . 54PSTN operation .

HP Color LaserJet Pro M452 and HP Color LaserJet Pro MFP M477 Troubleshooting Manual