When an HP LaserJet M436 series multifunction printer displays Prepare TR. Roller or Replace TR. Roller, its internal maintenance counter has reached the 100,000-page threshold assigned to the transfer roller assembly. Performing an HP M436 TR roller reset through the printer’s hidden Tech Menu (Menu > # > 10043616 > Menu) zeros out the Transfer Roller page register and clears the warning from the control panel.
Because the transfer roller (HP Part Number W7U01-67901) does not contain an electronic chip or auto-reset fuse, the printer cannot detect when a new roller is installed. You must manually reset the counter after replacing the roller. Conversely, resetting the counter without inspecting or replacing a worn roller only silences the alert—it will not fix faded printouts, background graying, or an active C9-2220 transfer circuit fault.
Supported Printer Models and Part Specifications
The HP LaserJet M436 series uses an A3 monochrome laser engine originally developed on Samsung’s copier architecture. Because several HP A3 models share this mechanical platform and firmware structure, the same transfer roller replacement and Tech Menu reset procedure applies across the engine family:
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HP LaserJet MFP M436 Series: M436n, M436dn, M436nda
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Shared Engine Family: HP LaserJet MFP M433a, M437n, M437dn, M437nda, M438n, M438dn, M438nda, M439n, M439dn, M439nda, M440n, M440dn, M440nda, M442dn, and M443nda
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Replacement Component: HP Transfer Roller Kit, part number W7U01-67901 (note that some HP service manual error tables contain a typographical misprint listing
W7401-67901, whereas the official parts catalog specifiesW7U01-67901) -
Rated Maintenance Yield: Approximately 100,000 simplex pages
Understanding Transfer Roller Warnings vs. Hardware Error Codes
Before clearing the counter, verify which code or message appears on the 4-line LCD screen or system status report. The printer distinguishes between routine life-cycle warnings and electrical transfer failures:
| Control Panel Message | Status / Error Code | Root Cause | Required Action |
| Prepare TR. Roller / Prepare with new transfer roller | C9-2110 / C9-2120 |
The transfer roller counter is approaching or has reached its 100,000-page rated life. | Inspect or replace the transfer roller (W7U01-67901), then clear the Transfer Roller count in Tech Mode. |
| Replace TR. Roller | C9-2120 / C9-2210 |
The maintenance counter has exceeded the rated threshold, triggering an amber status light. | Replace the worn transfer roller if print quality has degraded, then run the Tech Menu counter reset. |
| TR Failure: #C9-2220. Install TR roller again | C9-2220 |
The transfer roller is unseated, its conductive bearing contact is dirty, or the High Voltage Power Supply (HVPS) board is failing. | Reseat or replace the transfer roller and inspect the metal bias springs. If the fault remains, diagnose the HVPS board (SAM-JC44-00229A). |
Clearing the maintenance counter removes life warnings (C9-2110, C9-2120, and C9-2210), but it cannot override an active electrical fault (C9-2220) if the bias circuit fails its self-test at startup.
How to Inspect and Replace the HP M436 Transfer Roller
The transfer roller sits inside the right-side door directly opposite the imaging unit’s organic photoconductor (OPC) drum. During printing, the High Voltage Power Supply applies a positive DC charge to the roller to pull negatively charged toner off the drum and onto the paper passing between them.
When an HP M436 replace TR roller alert appears, inspect the roller’s foam surface before deciding whether to reset the existing part or install a new kit:
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Power off and unplug the printer: Turn off the main power switch and disconnect the AC power cord. High-voltage bias contacts sit directly beneath the transfer roller mounts.
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Open the right-side access cover: Pull the latch on the right side of the machine (
side cover) and swing the door down to expose the vertical paper path. -
Inspect the black foam roller: Locate the black conductive foam cylinder running horizontally across the inside of the right door assembly. Look for flattened spots, surface pitting, tears, or heavy toner caking.
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Handling precaution: Never touch the black sponge surface with bare fingers. Skin oils alter the electrical conductivity of the foam and leave repeating light bands or blank voids on printed pages. Do not vacuum the roller with a standard ungrounded shop vacuum, as static discharge can damage the HVPS circuit.
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Remove the old transfer roller: If the roller is worn or has reached 100,000 pages with declining print density, pinch or release the plastic retaining clips at both ends of the transfer roller shaft and lift the roller out of its spring-loaded brackets.
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Install the new transfer roller (
W7U01-67901): Hold the replacement roller strictly by its end bushings or shaft stubs. Align the keyed drive gear end with the matching side of the mount, press both shaft ends down into the left and right spring-loaded holders until they click into place, and verify that the roller spins and compresses smoothly against its springs. -
Close the right-side cover: Swing the side door shut until both latches lock, then reconnect the power cord and turn the printer on.
